' 
 
AUTOBIOGRAPHY 
 
 OF 
 
 SIR GEORGE BIDDELL AIRY, K.C.B. 
 
I 
 
 SonDon: c. J. CLAY AND SONS, 
 
 CAMBRIDGE UNIVERSITY PRESS WAREHOUSE, 
 
 AVE MARIA LANE. 
 
 263, ARGYLE STREET. 
 
 : F. A. BROCKHAUS. 
 Sorfe: THE MACMILLAN CO. 
 
AUTOBIOGRAPHY 
 
 OF 
 
 SIR GEORGE BIDDELL AIRY, K.C.B., 
 
 M.A., LL.D., D.C.L., F.R.S, F.R.A.S., 
 
 HONORARY FELLOW OF TRINITY COLLEGE, CAMBRIDGE, 
 ASTRONOMER ROYAL FROM 1836 TO l88l. 
 
 EDITED BY 
 
 WILFRID AIRY, B.A., M.lNST.CE, 
 
 CAMBRIDGE: 
 
 AT THE UNIVERSITY PRESS. 
 1896 
 
 [All Rights reserved] 
 

 Cambridge : 
 
 PRINTED BY J. AND C. F. CLAY, 
 AT THE UNIVERSITY PRESS. 
 

 PREFACE. 
 
 THE life of Airy was essentially that of a hard-working, 
 business man, and differed from that of other hard-working 
 people only in the quality and variety of his work. It was 
 not an exciting life, but it was full of interest, and his work 
 brought him into close relations with many scientific men, 
 and with many men high in the State. His real business 
 life commenced after he became Astronomer Royal, and 
 from that time forward, during the 46 years that he remained 
 in office, he was so entirely wrapped up in the duties of his 
 post that the history of the Observatory is the history of his 
 life. For writing his business life there is abundant material, 
 for he preserved all his correspondence, and the chief sources 
 of information are as follows : 
 
 (1) His Autobiography. 
 
 (2) His Annual Reports to the Board of Visitors. 
 
 (3) His printed Papers entitled Papers by G. B. Airy." 
 
 (4) His miscellaneous private correspondence. 
 
 (5) His letters to his wife. 
 
 (6) His business correspondence. 
 
 (i) His Autobiography, after the time that he became 
 Astronomer Royal, is, as might be expected, mainly a record 
 of the scientific work carried on at the Greenwich Obser- 
 vatory : but by no means exclusively so. About the time 
 when he took charge of the Observatory there was an 
 immense development of astronomical enterprise : observa- 
 tories were springing up in all directions, and the Astronomer 
 
 A B. 239026 *. 
 
 .*"' 
 
Vi PREFACE. 
 
 Royal was expected to advise upon all of the British and 
 Colonial Observatories. It was 'necessary also for him to 
 keep in touch with the Continental Observatories and their 
 work, and this he did very diligently and successfully, both 
 by correspondence and personal intercourse with the foreign 
 astronomers. There was also much work on important 
 subjects more or less connected with his official duties such 
 as geodetical survey work, the establishment of time-balls 
 at different places, longitude determinations, observation of 
 eclipses, and the determination of the density of the Earth. 
 Lastly, there was a great deal of time and work given 
 to questions not very immediately connected with his office, 
 but on which the Government asked his assistance in the 
 capacity of general scientific adviser : such were the Cor- 
 rection of the Compass in iron ships, the Railway Gauge 
 Commission, the Commission for the Restoration of the 
 Standards of Length and Weight, the Maine Boundary, Light- 
 houses, the Westminster Clock, the London University, and 
 many other questions. 
 
 Besides those above-mentioned there were a great many 
 subjects which he took up out of sheer interest in the 
 investigations. For it may fairly be said that every subject 
 of a distinctly practical nature, which could be advanced by 
 mathematical knowledge, had an interest for him : and his 
 incessant industry enabled him to find time for many of 
 them. Amongst such subjects were Tides and Tidal Obser- 
 vations, Clockwork, and the Strains in Beams and Bridges. 
 A certain portion of his time was also given to Lectures, 
 generally on current astronomical questions, for he held it as 
 his duty to popularize the science as far as lay in his power. 
 And he attended the meetings of the Royal Astronomical 
 Society with great regularity, and took a very active part in 
 the discussions and business of the Society. He also did 
 much work for the Royal Society, and (up to a certain date) 
 for the British Association. 
 
PREFACE. vii 
 
 All of the foregoing matters are recorded pretty fully in 
 his Autobiography up to the year 1861. After that date the 
 Autobiography is given in a much more abbreviated form, 
 and might rather be regarded as a collection of notes for his 
 Biography. His private history is given very fully for the 
 first part of his life, but is very lightly touched upon during 
 his residence at Greenwich. A great part of the Auto- 
 biography is in a somewhat disjointed state, and appears to 
 have been formed by extracts from a number of different 
 sources, such as Official Journals, Official Correspondence, 
 and Reports. In editing the Autobiography it has been 
 thought advisable to omit a large number of short notes 
 relating to the routine work of the Observatory, to technical 
 and scientific correspondence, to Papers communicated to 
 various Societies and official business connected with them, 
 and to miscellaneous matters of minor importance. These in 
 the aggregate occupied a great deal of time and attention. 
 But, from their detached nature, they would have but little 
 general interest. At various places will be found short 
 Memoirs and other matter by the Editor. 
 
 (2) All of his Annual Reports to the Board of Visitors are 
 attached to his Autobiography and were evidently intended 
 to be read with it and to form part of it. These Reports 
 are so carefully compiled and are so copious that they form 
 a very complete history of the Greenwich Observatory and 
 of the work carried on there during the time that he was 
 Astronomer Royal. The first Report contained only four 
 pages, but with the constantly increasing amount and range 
 of work the Reports constantly increased in volume till the 
 later Reports contained 21 pages. Extracts from these 
 Reports relating to matters of novelty and importance, and 
 illustrating the principles which guided him in his conduct 
 of the Observatory, have been incorporated with the Auto- 
 biography. 
 
 (3) The printed " Papers by G. B. Airy " are bound in 
 
Vlll PREFACE. 
 
 14 large quarto volumes. There are 518 of these Papers, 
 on a great variety of subjects : a list of them is appended 
 to this history, as also is a list of the books that he wrote, 
 and one or two of the Papers which were separately printed. 
 They form a very important part of his life's work, and are 
 frequently referred to in the present history. They are 
 almost all to be found in the Transactions of Societies or 
 in newspapers, and extend over a period of 63 years (1822 
 to 1885). The progress made in certain branches of science 
 during this long period can very fairly be traced by these 
 Papers. 
 
 (4) His private correspondence was large, and like his 
 other papers it was carefully arranged. No business letters 
 of any kind are included under this head. In this corre- 
 spondence letters are occasionally found either dealing with 
 matters of importance or in some way characteristic, and 
 these have been inserted in this biography. As already 
 stated the Autobiography left by Airy is confined almost 
 entirely to science and business, and touches very lightly on 
 private matters or correspondence. 
 
 (5) The letters to his wife are very numerous. They 
 were written during his occasional absences from home on 
 business or for relaxation. On these occasions he rarely let 
 a day pass without writing to his wife, and sometimes he 
 wrote twice on the same day. They are full of energy and 
 interest and many extracts from them are inserted in this 
 history. A great deal of the personal history is taken from 
 them. 
 
 (6) All correspondence in any way connected with 
 business during the time that he was Astronomer Royal 
 is to be found at the Royal Observatory. It is all bound 
 and arranged in the most perfect order, and any letter 
 throughout this time can be found with the greatest ease. 
 It is very bulky, and much of it is, in a historical sense, very 
 interesting. It was no doubt mainly from this correspondence 
 
PREFACE. IX 
 
 that the Autobiography, which so far as related to the 
 Greenwich part of it was almost entirely a business history, 
 was compiled. 
 
 The history of the early part of his life was written in 
 great detail and contained a large quantity of family matter 
 which was evidently not intended for publication. This part 
 of the Autobiography has been compressed. The history of 
 the latter part of his life was not written by himself at all, 
 and has been compiled from his Journal and other sources. 
 In both these cases, and occasionally in short paragraphs 
 throughout the narrative, it has been found convenient to 
 write the history in the third person. 
 
 2, THE CIRCUS, 
 
 GREENWICH. 
 
 NOTE. 
 
 The Syndics of the Cambridge University Press desire to express 
 their thanks to Messrs Macmillan & Co. for their courteous per- 
 mission to use in this work the steel engraving of Sir George Biddell 
 Airy published in Nature on October 31, 1878. 
 
' 
 
TABLE OF CONTENTS. 
 
 CHAPTER I. 
 
 PAGES 
 
 Personal Sketch of George Biddell Airy . . . . i 13 
 
 CHAPTER II. 
 
 From his birth to his taking his B.A. Degree at Cam- 
 bridge . . . . . .... 14 48 
 
 CHAPTER III. 
 
 At Trinity College, Cambridge, from his taking his B.A. 
 Degree to his taking charge of the Cambridge 
 Observatory as Plumian Professor. . . . 49 81 
 
 CHAPTER IV. 
 
 At Cambridge Observatory, from his taking charge of 
 the Cambridge Observatory to his residence at 
 Greenwich Observatory as Astronomer Royal . 82 122 
 
 CHAPTER V. 
 At Greenwich Observatory, 1836 1846 . . . 123 177 
 
 CHAPTER VI. 
 
 At Greenwich Observatory, 1846 1856 . - . . 178 225 
 
 CHAPTER VII. 
 At Greenwich Observatory, 1856 1866 . . ; 226 261 
 
 CHAPTER VIII. 
 
 At Greenwich Observatory, 1866 1876 . . . 262 314 
 
Xll TABLE OF CONTENTS. 
 
 CHAPTER IX. 
 
 PAGES 
 
 At Greenwich Observatory, from January ist, 1876, to 
 
 his resignation of office on August i5th, 1881 . 315 345 
 
 CHAPTER X. 
 
 At the White House, Greenwich, from his resignation of 
 office on August i5th, 1881, to his death on 
 January 2nd, 1892 ...... 346 368 
 
 APPENDIX. 
 
 List of Printed Papers by G. B. Airy, and List of Books 
 
 written by G.-B. Airy ...... 369 404 
 
 INDEX ... 405 414 
 
CHAPTER I. 
 
 PERSONAL SKETCH OF GEORGE BIDDELL AIRY. 
 
 THE history of Airy's life, and especially the history of his 
 life's work, is given in the chapters that follow. But it is felt 
 that the present Memoir would be incomplete without a 
 reference to those personal characteristics upon which the 
 work of his life hinged and which can only be very faintly 
 gathered from his Autobiography. 
 
 He was of medium stature and not powerfully built : as 
 he advanced in years he stooped a good deal. His hands 
 were large-boned and well-formed. His constitution was 
 remarkably sound. At no period in his life does he seem to 
 have taken the least interest in athletic sports or competitions, 
 but he was a very active pedestrian and could endure a 
 great deal of fatigue. He was by no means wanting in 
 physical courage, and on various occasions, especially in 
 boating expeditions, he ran considerable risks. In debate 
 and controversy he had great self-reliance, and was abso- 
 lutely fearless. His eye-sight was peculiar, and required 
 correction by spectacles the lenses of which were ground to 
 peculiar curves according to formulae which he himself in- 
 vestigated : with these spectacles he saw extremely well, and 
 he commonly carried three pairs, adapted to different 
 distances : he took great interest in the changes that took 
 place in his eye-sight, and wrote several Papers on the 
 subject. In his later years he became somewhat deaf, but 
 not to the extent of serious personal inconvenience. 
 
 A. B. i 
 
GEORGE BIDDELL AIRY. 
 
 The ruling feature of his character was undoubtedly Order. 
 From the time that he went up to Cambridge to the end of 
 his life his system of order was strictly maintained. He 
 wrote his autobiography up to date soon after he had taken 
 his degree, and made his first will as soon as he had any 
 money to leave. His accounts were perfectly kept by double 
 entry throughout his life, and he valued extremely the order 
 of book-keeping: this facility of keeping accounts was very 
 useful to him. He seems not to have destroyed a document 
 of any kind whatever : counterfoils of old cheque-books, notes 
 for tradesmen, circulars, bills, and correspondence of all sorts 
 were carefully preserved in the most complete order from the 
 time that he went to Cambridge ; and a huge mass they 
 formed. To a high appreciation of order he attributed in a 
 great degree his command of mathematics, and sometimes 
 spoke of mathematics as nothing more than a system of order 
 carried to a considerable extent. In everything he was 
 methodical and orderly, and he had the greatest dread of 
 disorder creeping into the routine work of the Observatory, 
 even in the smallest matters. As an example, he spent a 
 whole afternoon in writing the word " Empty " on large cards, 
 to be nailed upon a great number of empty packing boxes, 
 because he noticed a little confusion arising from their getting 
 mixed with other boxes containing different articles ; and an 
 assistant could not be spared for this work without with- 
 drawing him from his appointed duties. His arrangement of 
 the Observatory correspondence was excellent and elaborate : 
 probably no papers are more easy of reference than those 
 arranged on his system. His strict habits of order made him 
 insist very much upon detail in his business with others, and 
 the rigid discipline arising out of his system of order made 
 his rule irksome to such of his subordinates as did not 
 conform readily to it : but the efficiency of the Observatory 
 unquestionably depended mainly upon it. As his powers 
 failed with age the ruling passion for order assumed a greater 
 prominence; and in his last days he seemed to be more 
 
PERSONAL SKETCH. 
 
 anxious to put letters which he received into their proper 
 place for reference than even to master their contents. 
 
 His nature was eminently practical, and any subject which 
 had a distinctly practical object, and could be advanced by 
 mathematical investigation, possessed interest for him. And 
 his dislike of mere theoretical problems and investigations 
 was proportionately great. He was continually at war with 
 some of the resident Cambridge mathematicians on this 
 subject. Year after year he criticised the Senate House 
 Papers and the Smith's Prize Papers question by question 
 very severely : and conducted an interesting and acrimonious 
 private correspondence with Professor Cayley on the same 
 subject. His great mathematical powers and his command 
 of mathematics are sufficiently evidenced by the numerous 
 mathematical treatises of the highest order which he published, 
 a list of which is appended to this biography. But a very 
 important feature of his investigations was the thoroughness 
 of them. He was never satisfied with leaving a result as 
 a barren mathematical expression. He would reduce it, if 
 possible, to a practical and numerical form, at any cost of 
 labour : and would use any approximations which would 
 conduce to this result, rather than leave the result in an un- 
 fruitful condition. He never shirked arithmetical work : the 
 longest and most laborious reductions had no terrors for him, 
 and he was remarkably skilful with the various mathematical 
 expedients for shortening and facilitating arithmetical work 
 of a complex character. This power of handling arithmetic 
 was of great value to him in the Observatory reductions and 
 in the Observatory work generally. He regarded it as a duty 
 to finish off his work, whatever it was, and the writer well 
 remembers his comment on the mathematics of one of his old 
 friends, to the effect that " he was too fond of leaving a result 
 in the form of three complex equations with three unknown 
 quantities." To one who had known, in some degree, of the 
 enormous quantity of arithmetical work which he had turned 
 out, and the unsparing manner in which he had devoted 
 
 I 2 
 
GEORGE BIDDELL AIRY. 
 
 himself to it, there was something very pathetic in his 
 discovery, towards the close of his long life, "that the figures' 
 would not add up." 
 
 His energy and business capacity were remarkable. He 
 was made for work and could not long be happy without it. 
 Whatever subject he was engaged upon, he kept his object 
 clearly in view, and made straight for it, aiming far more 
 at clearness and directness than at elegance of periods or 
 symmetry of arrangement. He wrote his letters with great 
 ease and rapidity: and having written them he very rarely 
 had occasion to re-write them, though he often added inser- 
 tions and interlineations, even in the most important official 
 letters. Without this it would have been impossible for him 
 to have turned out the enormous quantity of correspondence 
 that he did. He never dictated letters, and only availed him- 
 self of clerical assistance in matters of the most ordinary 
 routine. In his excursions, as in his work, he was always 
 energetic, and could not endure inaction. Whatever there 
 was of interest in the places that he visited he examined 
 thoroughly and without delay, and then passed on. And he 
 thus accomplished a great deal in a short vacation. His 
 letters written to his wife, while he was on his excursions, are 
 very numerous and characteristic, and afford ample proofs of 
 his incessant energy and activity both of body and mind. 
 They are not brilliantly written, for it was not in his nature 
 to write for effect, and he would never give himself the 
 trouble to study the composition of his letters, but they are 
 straight-forward, clear, and concise, and he was never at a 
 loss for suitable language to express his ideas. He had a 
 wonderful capacity for enjoyment : the subjects that chiefly 
 interested him were scenery, architecture, and antiquities, but 
 everything novel or curious had an interest for him. He 
 made several journeys to the Continent, but by far the 
 greater number of his excursions were made in England and 
 Scotland, and there were few parts of the country which he 
 had not visited. He was very fond of the Lake District of 
 
PERSONAL SKETCH. 5 
 
 Cumberland, and visited it very frequently, and each time 
 that he went there the same set of views had an eternal 
 freshness for him, and he wrote long descriptions of the 
 scenery and effects with the same raptures as if he had seen 
 it for the first time. Many of his letters were written from 
 Playford, a village in a beautiful part of Suffolk, a few miles 
 from Ipswich. Here he had a small property, and generally 
 stayed there for a short time once or twice a year. He was 
 extremely fond of this country, and was never tired of 
 repeating his walks by the well-known lanes and footpaths. 
 And, as in Cumberland, the Suffolk country had an eternal 
 freshness and novelty for him. Wherever he went he was 
 indefatigable in keeping up his acquaintance with his nu- 
 merous friends and his letters abound in social reminiscences. 
 
 His memory was singularly retentive. It was much 
 remarked at school in his early days, and in the course 
 of his life he had stored up in his memory an incredible 
 quantity of poetry, ballads, and miscellaneous facts and 
 information of all sorts, which was all constantly ready 
 and at his service. It is almost needless to add that his 
 memory was equally accurate and extensive in matters 
 connected with science or business. 
 
 His independence of character was no doubt due to and 
 inseparable from his great powers. The value of his scientific 
 work greatly depended upon his self-reliance and indepen- 
 dence of thought. And in the heavy work of remodelling 
 the Observatory it was a very valuable quality. This same 
 self-reliance made him in his latter years apt to draw 
 conclusions too confidently and hastily on subjects which 
 he had taken up more as a pastime than as work. But 
 whatever he touched he dealt with ably and in the most 
 fearless truthseeking manner, and left original and vigorous 
 opinions. 
 
 He had a remarkably well-balanced mind, and a simplicity 
 of nature that appeared invulnerable. No amount of hero- 
 worship seemed to have the least effect upon him. And 
 
GEORGE BIDDELL AIRY. 
 
 from a very early time he was exposed to a great deal 
 of it. His mind was incessantly engaged on investigations 
 of Nature, and this seems to have been with him, as has 
 been the case with others, a preserving influence. This 
 simplicity of character he retained throughout his life. At 
 the same time he was sensible and shrewd in his money 
 matters and attentive to his personal interests. And his 
 practical good sense in the general affairs of life, combined 
 with his calm and steady consideration of points submitted 
 to him, made his advice very valuable. This was especially 
 recognized by his own and his wife's relations, who consulted 
 him on many occasions and placed the fullest confidence in 
 his absolute sense of justice as well as in his wise counsel. 
 He was extremely liberal in proportion to his means, and 
 gave away money to a large extent to all who had any claim 
 upon him. But he was not in any sense reckless, and kept a 
 most cautious eye on his expenses. He was not indifferent 
 to the honours which he received in the scientific world, but 
 he does not appear to have sought them in any way, and he 
 certainly did not trouble himself about them. 
 
 His courtesy was unfailing : no amount of trouble could 
 shake it. Whether it was the Secretary of the Admiralty, or 
 a servant girl wanting her fortune told : whether a begging- 
 letter for money, or miscellaneous invitations : all had their 
 answer in the most clear and courteous language. But he 
 would not grant personal interviews when he could avoid it : 
 they took up too much of his time. His head was so clear 
 that he never seemed to want for the clearest and most direct 
 language in expressing his meaning, and his letters are 
 models of terseness. 
 
 In all his views and opinions he was strongly liberal. At 
 Cambridge at an early date he was one of the 83 members of 
 the Senate who supported the application to permit the 
 granting of medical degrees without requiring an expression 
 of assent to the religious doctrines of the Church of England. 
 And in 1868 he declined to sign a petition against the abo- 
 
PERSONAL SKETCH. 
 
 lition of religious declarations required of persons admitted 
 to Fellowships or proceeding to the degree of M.A. And he 
 was opposed to every kind of narrowness and exclusiveness. 
 When he was appointed to the post of Astronomer Royal, he 
 stipulated that he should not be asked to vote in any political 
 election. But all his views were in the liberal direction. He 
 was a great reader of theology and church history, and as 
 regarded forms of worship and the interpretation of the 
 Scriptures, he treated them with great respect, but from 
 the point of view of a freethinking layman. In the Preface 
 to his " Notes on the Earlier Hebrew Scriptures " he says, 
 "In regard to the general tone of these notes, I will first 
 remark that I have nothing to say on the subject of verbal 
 inspiration. With those who entertain that doctrine, I can 
 have nothing in common. Nor do I recognize, in the pro- 
 fessedly historical accounts, any other inspiration which can 
 exempt them from the severest criticism that would be 
 applicable to so-called profane accounts, written under the 
 same general circumstances, and in the same countries." And 
 his treatment of the subject in the " Notes " shews how 
 entirely he took a rationalistic view of the whole question. 
 He also strongly sided with Bishop Colenso in his fearless 
 criticism of the Pentateuch, though he dissented from some 
 of his conclusions. But he was deeply imbued with the spirit 
 of religion and reflected much upon it. His whole correspond- 
 ence conveys the impression of the most sterling integrity 
 and high-mindedness, without a trace of affectation. In no 
 letter does there appear a shadow of wavering on matters of 
 principle, whether in public or private matters, and he was 
 very clear and positive in his convictions. 
 
 The great secret of his long and successful official career 
 was that he was a good servant and thoroughly understood 
 his position. He never set himself in opposition to his 
 masters, the Admiralty. He never hesitated to ask the 
 Admiralty for what he thought right, whether in the way 
 of money grants for various objects, or for occasional 
 
GEORGE BIDDELL AIRY. 
 
 permission to give his services to scientific matters not 
 immediately connected with the Observatory. Sometimes 
 the Admiralty refused his requests, and he felt this very 
 keenly, but he was far too busy and energetic to trouble 
 himself about such little slights, and cheerfully accepted 
 the situation. What was refused by one Administration 
 was frequently granted by another; and in the meantime 
 he was always ready to give his most zealous assistance 
 in any matter that was officially brought before him. This 
 cheerful readiness to help, combined with his great ability 
 and punctuality in business matters, made him a very 
 valuable servant, and speaking generally he had the con- 
 fidence of the Admiralty in a remarkable degree. In many 
 of his Reports to the Board of Visitors he speaks gratefully 
 of the liberality of the Admiralty in forwarding scientific 
 progress and research. In matters too which are perhaps 
 of minor importance from the high stand-point of science, 
 but which are invaluable in the conduct of an important 
 business office, such for example as estimates and official 
 correspondence, he was orderly and punctual in the highest 
 degree. And, what is by no means unimportant, he possessed 
 an excellent official style in correspondence, combined with 
 great clearness of expression. His entire honesty of purpose, 
 and the high respect in which he was held both at home and 
 abroad, gave great weight to his recommendations. 
 
 With regard to his habits while he resided at the 
 Observatory, his custom was to work in his official room 
 from 9 to about 2.30, though in summer he was frequently 
 at work before breakfast. He then took a brisk walk, and 
 dined at about 3.30. This early hour had been prescribed 
 and insisted upon by his physician, Dr Haviland of Cam- 
 bridge, in whom he had great confidence. He ate heartily, 
 though simply and moderately, and slept for about an hour 
 after dinner. He then had tea, and from about 7 to 10 he 
 worked in the same room with his family. He would never 
 retire to a private room, and regarded the society of his family 
 
PERSONAL SKETCH. 
 
 as highly beneficial in " taking the edge off his work." His 
 powers of abstraction were remarkable : nothing seemed to 
 disturb him ; neither music, singing, nor miscellaneous con- 
 versation. He would then play a game or two at cards, 
 read a few pages of a classical or historical book, and retire 
 at ii. On Sundays he attended morning service at church, 
 and in the evening read a few prayers very carefully and 
 impressively to his whole household. He was very hospitable, 
 and delighted to receive his friends in a simple ^and natural 
 way at his house. In this he was most admirably aided by 
 his wife, whose grace and skill made everything pleasant to 
 their guests. But he avoided dinner-parties as much as 
 possible they interfered too much with his work and with 
 the exception of scientific and official dinners he seldom 
 dined away from home. His tastes were entirely domestic, 
 and he was very happy in his family. With his natural love 
 of work, and with the incessant calls upon him, he would 
 soon have broken down, had it not been for his system of 
 regular relaxation. Two or three times a year he took a 
 holiday: generally a short run of a week or ten days in 
 the spring, a trip of a month or thereabouts in the early 
 autumn, and about three weeks at Playford in the winter. 
 These trips were always conducted in the most active 
 manner, either in constant motion from place to place, or 
 in daily active excursions. This system he maintained with 
 great regularity, and from the exceeding interest and enjoy- 
 ment that he took in these trips his mind was so much 
 refreshed and steadied that he always kept himself equal 
 to his work. 
 
 Airy seems to have had a strong bent in the direction of 
 astronomy from his youth, and it is curious to note how well 
 furnished he was, by the time that he became Astronomer 
 Royal, both with astronomy in all its branches, and with the 
 kindred sciences so necessary for the practical working and 
 improvement of it. At the time that he went to Cambridge 
 Physical Astronomy was greatly studied there and formed a 
 
IO GEORGE BIDDELL AIRY. 
 
 most important part of the University course. He eagerly 
 availed himself of this, and mastered the Physical Astronomy 
 in the most thorough manner, as was evidenced by his Papers 
 collected in his " Mathematical Tracts," his investigation of 
 the Long Inequality of the Earth and Venus, and many 
 other works. As Plumian Professor he had charge of the 
 small Observatory at Cambridge, where he did a great deal 
 of the observing and reduction work himself, and became 
 thoroughly versed in the practical working of an Observatory. 
 The result of this was immediately seen in the improved 
 methods which he introduced at Greenwich, and which were 
 speedily imitated at other Observatories. Optics and the 
 Undulatory Theory of Light had been very favourite subjects 
 with him, and he had written and lectured frequently upon 
 them. In the construction of the new and powerful telescopes 
 and other optical instruments required from time to time 
 this knowledge was very essential, for in its instrumental 
 equipment the Greenwich Observatory was entirely re- 
 modelled during his tenure of office. And in many of the 
 matters referred to him, as for instance that of the Light- 
 houses, a thorough knowledge of Optics was most valuable. 
 He had made a great study of the theory and construction 
 of clocks, and this knowledge was invaluable to him at 
 Greenwich in the establishment of new and more accurate 
 astronomical clocks, and especially in the improvement of 
 chronometers. He had carefully studied the theory of 
 pendulums, and had learned how to use them in his ex- 
 periments in the Cornish mines. This knowledge he after- 
 wards utilized very effectively at the Harton Pit in comparing 
 the density of the Earth's crust with its mean density ; and 
 it was very useful to him in connection with geodetic surveys 
 and experiments on which he was consulted. And his 
 mechanical knowledge was useful in almost everything. 
 
 The subjects (outside those required for his professional 
 work) in which he took most interest were Poetry, History, 
 Theology, Antiquities, Architecture, and Engineering. He 
 
PERSONAL SKETCH. II 
 
 was well acquainted with standard English poetry, and had 
 committed large quantities to memory, which he frequently 
 referred to as a most valuable acquisition and an ever-present 
 relief and comfort to his mind. History and Theology he 
 had studied as opportunity offered, and without being widely 
 read in them he was much at home with them, and his 
 powerful memory made the most of what he did read. An- 
 tiquities and Architecture were very favourite subjects with 
 him. He had visited most of the camps and castles in the 
 United Kingdom and was never tired of tracing their con- 
 nection with ancient military events : and he wrote several 
 Papers on this subject, especially those relating to the Roman 
 Invasions of Britain. Ecclesiastical Architecture he was very 
 fond of: he had visited nearly all the cathedrals and principal 
 churches in England, and many on the Continent, and was 
 most enthusiastic on their different styles and merits : his 
 letters abound in critical remarks on them. He was ex- 
 tremely well versed in mechanics, and in the principles and 
 theory of construction, and took the greatest interest in large 
 engineering works. This led to much communication with 
 Stephenson, Brunei, and other Engineers, who consulted him 
 freely on the subject of great works on which they were 
 engaged : in particular he rendered much assistance in con- 
 nection with the construction of the Britannia Bridge over 
 the Menai Straits. There were various other subjects which 
 he read with much interest (Geology in particular), but he 
 made no study of Natural History, and knew very little about 
 it beyond detached facts. His industry was untiring, and in 
 going over his books one by one it was very noticeable how 
 large a number of them were feathered with his paper 
 "marks," shewing how carefully he had read them and 
 referred to them. His nature was essentially cheerful, and 
 literature of a witty and humourous character had a great 
 charm for him. He was very fond of music and knew a 
 great number of songs; and he was well acquainted with the 
 
12 GEORGE BIDDELL AIRY. 
 
 theory of music: but he was no performer. He did not 
 sketch freehand but made excellent drawings with his Camera 
 Lucida. 
 
 At the time when he took his degree (1823) and for many 
 years afterwards there was very great activity of scientific 
 investigation and astronomical enterprise in England. And, 
 as in the times of Flamsteed and Halley, the earnest zeal of 
 men of science occasionally led to much controversy and 
 bitterness amongst them. Airy was by no means exempt 
 from such controversies. He was a man of keen sensitive- 
 ness, though it was combined with great steadiness of temper, 
 and he never hesitated to attack theories and methods that 
 he considered to be scientifically wrong. This led to dif- 
 ferences with Ivory, Challis, South, Cayley, Archibald Smith, 
 and others ; but however much he might differ from them he 
 was always personally courteous, and the disputes generally 
 went no farther than as regarded the special matter in 
 question. Almost all these controversial discussions were 
 carried on openly, and were published in the Athenaeum, the 
 Philosophical Magazine, or elsewhere ; for he printed nearly 
 everything that he wrote, and was very careful in the selection 
 of the most suitable channels for publication. He regarded it 
 as a duty to popularize as much as possible the work done at 
 the Observatory, and to take the public into his confidence. 
 And this he effected by articles communicated to newspapers, 
 lectures, numerous Papers written for scientific societies, 
 reports, debates, and critiques. 
 
 His strong constitution and his regular habits, both of 
 work and exercise, are sufficient explanation of the good 
 health which in general he enjoyed. Not but what he had 
 sharp touches of illness from time to time. At one period he 
 suffered a good deal from an attack of eczema, and at another 
 from a varicose vein in his leg, and he was occasionally 
 troubled with severe colds. But he bore these ailments with 
 great patience and threw them off in course of time. He was 
 
PERSONAL SKETCH. 13 
 
 happy in his marriage and in his family, and such troubles 
 and distresses as were inevitable he accepted calmly and 
 quietly. In his death, as in his life, he was fortunate : he had 
 no long or painful illness, and he was spared the calamity of 
 aberration of intellect, the saddest of all visitations. 
 
CHAPTER II. 
 
 FROM HIS BIRTH TO HIS TAKING HIS B.A. DEGREE 
 AT CAMBRIDGE. 
 
 FROM JULY 2/TH 1801 TO JANUARY ISTH 1823. 
 
 GEORGE BIDDELL AIRY was born at Alnwick in North- 
 umberland on July 27th 1801. His father was William Airy 
 of Luddington in Lincolnshire, the descendant of a long line 
 of Airys who have been traced back with a very high degree 
 of probability to a family of that name which was settled at 
 Kentmere in Westmorland in the I4th century. A branch of 
 this family migrated to Pontefract in Yorkshire, where they 
 seem to have prospered for many years, but they were involved 
 in the consequences of the Civil Wars, and one member of 
 the family retired to Ousefleet in Yorkshire. His grandson 
 removed to Luddington in Lincolnshire, where his descendants 
 for several generations pursued the calling of small farmers. 
 George Biddell Airy's mother, Ann Airy, was the daughter of 
 George Biddell, a well-to-do farmer in Suffolk. 
 
 William Airy, the father of George Biddell Airy, was a 
 man of great activity and strength, and of prudent and steady 
 character. When a young man he became foreman on a 
 farm in the neighbourhood of Luddington, and laid by his 
 earnings in summer in order to educate himself in winter. 
 For a person in his rank, his education was unusually good, 
 in matters of science and in English literature. But at the 
 age of 24 he grew tired of country labour, and obtained a 
 post in the Excise. After serving in various Collections he 
 was appointed Collector of the Northumberland Collection 
 
FROM BIRTH TO B.A. DEGREE. 15 
 
 on the 1 5th August 1800, and during his service there his 
 eldest son George Biddell Airy was born. The time over 
 which his service as Officer and Supervisor extended was 
 that in which smuggling rose to a very high pitch, and 
 in which the position of Excise Officer was sometimes 
 dangerous. He was remarkable for his activity and boldness 
 in contests with smugglers, and made many seizures. Ann 
 Airy, the mother of George Biddell Airy, was a woman of 
 great natural abilities both speculative and practical, kind as 
 a neighbour and as head of a family, and was deeply loved 
 and respected. The family consisted of George Biddell, 
 Elizabeth, William, and Arthur who died young. 
 
 William Airy was appointed to Hereford Collection on 
 22nd October 1802, and removed thither shortly after. He 
 stayed at Hereford till he was appointed to Essex Collection 
 on 28th February 1810, and during this time George Biddell 
 was educated at elementary schools in writing, arithmetic, 
 and a little Latin. He records of himself that he was not a 
 favourite with the schoolboys, for he had very little animal 
 vivacity and seldom joined in active play with his school- 
 fellows. But in the proceedings of the school he was suc- 
 cessful, and was a favourite with his master. 
 
 On the appointment of William Airy to Essex Collection, 
 the family removed to Colchester on April 5th 1810. Here 
 George Biddell was first sent to a large school in Sir Isaac's 
 Walk, then kept by Mr Byatt Walker, and was soon noted for 
 his correctness in orthography, geography, and arithmetic. 
 He evidently made rapid progress, for on one occasion Mr 
 Walker said openly in the schoolroom how remarkable it was 
 that a boy 10 years old should be the first in the school. At 
 this school he stayed till the end of 1813 and thoroughly 
 learned arithmetic (from Walkingame's book), book-keeping 
 by double entry (on which knowledge throughout his life 
 he set a special value), the use of the sliding rule (which 
 knowledge also was specially useful to him in after life), 
 mensuration and algebra (from Bonnycastle's books). He 
 
1 6 GEORGE BIDDELL AIRY. 
 
 also studied grammar in all its branches, and geography, 
 and acquired some knowledge of English literature, beginning 
 with that admirable book The Speaker, but it does not appear 
 that Latin and Greek were attended to at this school. He 
 records that at this time he learned an infinity of snatches 
 of songs, small romances, &c., which his powerful memory 
 retained most accurately throughout his life. He was no 
 hand at active play: but was notorious for his skill in con- 
 structing guns for shooting peas and arrows, and other 
 mechanical contrivances. At home he relates that he picked 
 up a wonderful quantity of learning from his father's books. 
 He read and remembered much poetry from such standard 
 authors as Milton, Pope, Gay, Gray, Swift, &c., which was 
 destined to prove in after life an invaluable relaxation for his 
 mind. But he also studied deeply an excellent Cyclopaedia 
 called a Dictionary of Arts and Sciences in three volumes 
 folio, and learned from it much about ship-building, naviga- 
 tion, fortification, and many other subjects. 
 
 During this period his valuable friendship with his uncle 
 Arthur Biddell commenced. Arthur Biddell was a prosperous 
 farmer and valuer at Playford near Ipswich. He was a well- 
 informed and able man, of powerful and original mind, 
 extremely kind and good-natured, and greatly respected 
 throughout the county. In the Autobiography of George 
 Biddell Airy he states as follows : 
 
 " I do not remember precisely when it was that I first 
 visited my uncle Arthur Biddell. I think it was in a winter : 
 certainly as early as the winter of 1812 13. Here I found a 
 friend whose society I could enjoy, and I entirely appreciated 
 and enjoyed the practical, mechanical, and at the same time 
 speculative and enquiring talents of Arthur Biddell. He had 
 a library which, for a person in middle life, may be called 
 excellent, and his historical and antiquarian knowledge was 
 not small. After spending one winter holiday with him, it 
 easily came to pass that I spent the next summer holiday 
 with him : and at the next winter holiday, finding that there 
 
FROM BIRTH TO B.A. DEGREE. 17 
 
 was no precise arrangement for my movements, I secretly 
 wrote him a letter begging him to come with a gig to fetch 
 me home with him : he complied with my request, giving no 
 hint to my father or mother of my letter : and from that 
 time, one-third of every year was regularly spent with him 
 till I went to College. How great was the influence of this 
 on my character and education I cannot tell. It was with 
 him that I became acquainted with the Messrs Ransome, 
 W. Cubitt the civil engineer (afterwards Sir W. Cubitt), 
 Bernard Barton, Thomas Clarkson (the slave-trade aboli- 
 tionist), and other persons whose acquaintance I have valued 
 highly. It was also with him that I became acquainted with 
 the works of the best modern poets, Scott, Byron, Campbell, 
 Hogg, and others : as also with the Waverley Novels and 
 other works of merit." 
 
 In 1813 William Airy lost his appointment of Collector 
 of Excise and was in consequence very much straitened 
 in his circumstances. But there was no relaxation in the 
 education of his children, and at the beginning of 1814 
 George Biddell was sent to the endowed Grammar School 
 at Colchester, then kept by the Rev. E. Crosse, and remained 
 there till the summer of 1819, when he went to College. 
 The Autobiography proceeds as follows : 
 
 " I became here a respectable scholar in Latin and Greek, 
 to the extent of accurate translation, and composition of 
 prose Latin : in regard to Latin verses I was I think more 
 defective than most scholars who take the same pains, but 
 I am not much ashamed of this, for I entirely despise the 
 system of instruction in verse composition. 
 
 " My father on some occasion had to go to London and 
 brought back for me a pair of 1 2-inch globes. They were 
 invaluable to me. The first stars which I learnt from the 
 celestial globe were a Lyrae, a Aquilae, a Cygni : and to this 
 time I involuntarily regard these stars as the birth-stars of 
 my astronomical knowledge. Having somewhere seen a 
 description of a Gunter's quadrant, I perceived that I could 
 
 A. B. 2 
 
1 8 GEORGE BIDDELL AIRY. 
 
 construct one by means of the globe : my father procured 
 for me a board of the proper shape with paper pasted on 
 it, and on this I traced the lines of the quadrant. 
 
 " My command of geometry was tolerably complete, and 
 one way in which I frequently amused myself was by making 
 paper models (most carefully drawn in outline) which were 
 buttoned together without any cement or sewing. Thus I 
 made models, not only of regular solids, regularly irregular 
 solids, cones cut in all directions so as to shew the conic 
 sections, and the like, but also of six-gun batteries, intrench- 
 ments and fortresses of various kinds &c. 
 
 " From various books I had learnt the construction of the 
 steam-engine : the older forms from the Dictionary of Arts 
 and Sciences ; newer forms from modern books. The newest 
 form however (with the sliding steam valve) I learnt from a 
 6-horse engine at Bawtrey's brewery (in which Mr Keeling 
 the father of my schoolfellow had acquired a partnership). I 
 frequently went to look at this engine, and on one occasion 
 had the extreme felicity of examining some of its parts when 
 it was opened for repair. 
 
 " In the mean time my education was advancing at 
 Playford. The first record, I believe, which I have of my 
 attention to mechanics there is the plan of a threshing- 
 machine which I drew. But I was acquiring valuable infor- 
 mation of all kinds from the Encyclopaedia Londinensis, a 
 work which without being high in any respect is one of the 
 most generally useful that I have seen. But I well remember 
 one of the most important steps that I ever made. I had 
 tried experiments with the object-glass of an opera-glass and 
 was greatly astonished at the appearance of the images of 
 objects seen through the glass under different conditions. 
 By these things my thoughts were turned to accurate optics, 
 and I read with care Rutherford's Lectures, which my uncle 
 possessed. The acquisition of an accurate knowledge of the 
 effect of optical constructions was one of the most charming 
 attainments that I ever reached. Long before I went to 
 
FROM BIRTH TO B.A. DEGREE. 19 
 
 College I understood the action of the lenses of a telescope 
 better than most opticians. I also read with great zeal 
 Nicholson's Dictionary of Chemistry, and occasionally made 
 chemical experiments of an inexpensive kind : indeed I grew 
 so fond of this subject that there was some thought of 
 apprenticing me to a chemist. I also attended to surveying 
 and made a tolerable survey and map of my uncle's farm. 
 
 " At school I was going on successfully, and distinguished 
 myself particularly by my memory. It was the custom for 
 each boy once a week to repeat a number of lines of Latin or 
 Greek poetry, the number depending very much on his own 
 choice. I determined on repeating 100 every week, and I 
 never once fell below that number and was sometimes much 
 above it. It was no distress to me, and great enjoyment. 
 At Michaelmas 1816 I repeated 2394 lines, probably without 
 missing a word. I do not think that I was a favourite with 
 Mr Crosse, but he certainly had a high opinion of my powers 
 and expressed this to my father. My father entertained the 
 idea of sending me to College, which Mr Crosse recom- 
 mended : but he heard from some college man that the 
 expense would be 200 a year, and he laid aside all thoughts 
 of it. 
 
 "The farm of Playford Hall was in 1813 or 1814 hired by 
 Thomas Clarkson, the slave-trade abolitionist. My uncle 
 transacted much business for him (as a neighbour and friend) 
 in the management of the farm &c. for a time, and they 
 became very intimate. My uncle begged him to examine 
 me in Classical knowledge, and he did so, I think, twice. He 
 also gave some better information about the probable ex- 
 penses &c. at College. The result was a strong recommen- 
 dation by my uncle or through my uncle that I should be 
 sent to Cambridge, and this was adopted by my father. I 
 think it likely that this was in 1816. 
 
 "In December 1816, Dealtry's Fluxions was bought for me, 
 and I read it and understood it well. I borrowed Hutton's 
 Course of Mathematics of old Mr Ransome, who had come to 
 
 2 2 
 
2O GEORGE BIDDELL AIRY. 
 
 reside at Greenstead near Colchester, and read a good deal 
 of it. 
 
 "About Ladyday 1817 I began to read mathematics with 
 Mr Rogers (formerly, I think, a Fellow of Sidney College, and 
 an indifferent mathematician of the Cambridge school), who 
 had succeeded a Mr Tweed as assistant to Mr Crosse in the 
 school. I went to his house twice a week, on holiday after- 
 noons. I do not remember how long I received lessons from 
 him, but I think to June 1818. This course was extremely 
 valuable to me, not on account of Mr Rogers's abilities (for I 
 understood many things better than he did) but for its train- 
 ing me both in Cambridge subjects and in the Cambridge 
 accurate methods of treating them. I went through Euclid 
 (as far as usually read), Wood's Algebra, Wood's Mechanics, 
 .Vince's Hydrostatics, Wood's Optics, Trigonometry (in a 
 geometrical treatise and also in Woodhouse's algebraical 
 form), Fluxions to a good extent, Newton's Principia to the 
 end of the 9th section. This was a large quantity, but I 
 read it accurately and understood it perfectly, and could 
 write out any one of the propositions which I had read in 
 the most exact form. My connexion with Mr Rogers was 
 terminated by his giving me notice that he could not under- 
 take to receive me any longer : in fact I was too much for 
 him. I generally read these books in a garret in our house 
 in George Lane, which was indefinitely appropriated to my 
 brother and myself. I find that I copied out Vince's Conic 
 Sections in February 1819. The first book that I copied was 
 the small geometrical treatise on Trigonometry, in May 
 1817: to this I was urged by old Mr Ransome, upon my 
 complaining that I could not purchase the book : and it was 
 no bad lesson of independence to me." 
 
 During the same period 1817 1819 he was occupied 
 at school on translations into blank verse from the ^neid 
 and Iliad, and read through the whole of Sophocles very 
 carefully. 
 
 The Classical knowledge which he thus gained at school 
 
FROM BIRTH TO B.A. DEGREE. 21 
 
 and subsequently at Cambridge was sound, and he took 
 great pleasure in it : throughout his life he made a practice 
 of keeping one or other of the Classical Authors at hand for 
 occasional relaxation. He terminated his schooling in June 
 1819. Shortly afterwards his father left Colchester and went 
 to reside at Bury St Edmund's. The Autobiography pro- 
 ceeds as follows : 
 
 " Mr Clarkson was at one time inclined to recommend me 
 to go to St Peter's College (which had been much enriched 
 by a bequest from a Mr Gisborne). But on giving some 
 account of me to his friend Mr James D. Hustler, tutor of 
 Trinity College, Mr Hustler urged upon him that I was 
 exactly the proper sort of person to go to Trinity College. 
 And thus it was settled (mainly by Mr Clarkson) that I 
 should be entered at Trinity College. I think that I was 
 sent for purposely from Colchester to Playford, and on 
 March 6th, 1819, I rode in company with Mr Clarkson from 
 Playford to Sproughton near Ipswich to be examined by the 
 Rev. Mr Rogers, incumbent of Sproughton, an old M.A. of 
 Trinity College : and was examined, and my certificate duly 
 sent to Mr Hustler : and I was entered on Mr Hustler's side 
 as Sizar of Trinity College. 
 
 "In the summer of 1819 I spent some time at Playford. 
 On July 27th, 1819 (my birthday, 18 years old), Mr Clarkson 
 invited me to dinner, to meet Mr Charles Musgrave, Fellow 
 of Trinity College, who was residing for a short time at 
 Grundisburgh, taking the church duty there for Dr Ramsden, 
 the Rector. It was arranged that I should go to Grun- 
 disburgh the next day (I think) to be examined in mathe- 
 matics by Mr Musgrave. I went accordingly, and Mr 
 Musgrave set before me a paper of questions in geometry, 
 algebra, mechanics, optics, &c. ending with the first proposi- 
 tion of the Principia. I knew nothing more about my 
 answers at the time : but I found long after that they excited 
 so much admiration that they were transmitted to Cam- 
 bridge (I forget whether to Mr Musgrave's brother, a Fellow 
 
22 GEORGE BIDDELL AIRY. 
 
 of Trinity College and afterwards Archbishop of York, or 
 to Mr Peacock, afterwards Dean of Ely) and were long 
 preserved. 
 
 " The list of the Classical subjects for ,the first year in 
 Trinity College was transmitted to me, as usual, by Mr 
 Hustler. They were The Hippolytus of Euripides, the 
 3rd Book of Thucydides, and the 2nd Philippic of Cicero. 
 These I read carefully and noted before going up. Mr 
 Hustler's family lived in Bury; and I called on him and 
 saw him in October, introduced by Mr Clarkson. On the 
 morning of October i8th, 1819, 1 went on the top of the coach 
 to Cambridge, knowing nobody there but Mr Hustler, but 
 having letters of introduction from Mr Charles Musgrave to 
 Professor Sedgwick, Mr Thomas Musgrave, and Mr George 
 Peacock, all Fellows of Trinity College. 
 
 " I was set down at the Hoop, saw Trinity College for the 
 first time, found Mr Hustler, was conducted by his servant to 
 the robe-maker's, where I was invested in the cap and blue 
 gown, and after some further waiting was installed into 
 lodgings in Bridge Street. At 4 o'clock I went to the 
 College Hall and was introduced by Mr Hustler to several 
 undergraduates, generally clever men, and in the evening I 
 attended Chapel in my surplice (it being St Luke's day) 
 and witnessed that splendid service of which the occasional 
 exhibition well befits the place. 
 
 " As soon as possible, I called on Mr Peacock, Mr Mus- 
 grave, and Professor Sedgwick. By all I was received with 
 great kindness: my examination papers had been sent to them, 
 and a considerable reputation preceded me. Mr Peacock at 
 once desired that I would not consider Mr C. Musgrave's 
 letter as an ordinary introduction, but that I would refer to 
 him on all occasions. And I did so for several years, and 
 always received from him the greatest assistance that he 
 could give. I think that I did not become acquainted with 
 Mr Whewell till the next term, when I met him at a break- 
 fast party at Mr Peacock's. Mr Peacock at once warned me 
 
FROM BIRTH TO B.A. DEGREE. 23 
 
 to arrange for taking regular exercise, and prescribed a walk 
 of two hours every day before dinner : a rule to which I 
 attended regularly, and to which I ascribe the continuance of 
 good general health. 
 
 "I shewed Mr Peacock a manuscript book which contained 
 a number of original Propositions which I had investigated. 
 These much increased my reputation (I really had sense 
 enough to set no particular value on it) and I was soon 
 known by sight to almost everybody in the University. A 
 ridiculous little circumstance aided in this. The former rule 
 of the University (strictly enforced) had been that all 
 students should wear drab knee-breeches : and I, at Mr 
 Clarkson's recommendation, was so fitted up. The struggle 
 between the old dress and the trowsers customary in society 
 was still going on but almost terminated, and I was one of 
 the very few freshmen who retained the old habiliments. 
 This made me in some measure distinguishable : however at 
 the end of my first three terms I laid these aside. 
 
 " The College Lectures began on Oct. 22 : Mr Evans at 9 
 on the Hippolytus, and Mr Peacock at 10 on Euclid (these 
 being the Assistant Tutors on Mr Hustler's side) : and then I 
 felt myself established. 
 
 " I wrote in a day or two to my uncle Arthur Biddell, and 
 I received from him a letter of the utmost kindness. He 
 entered gravely on the consideration of my prospects, my 
 wants, &c. : and offered at all times to furnish me with 
 money, which he thought my father's parsimonious habits 
 might make him unwilling to do. I never had occasion to 
 avail myself of this offer: but it was made in a way which 
 in no small degree strengthened the kindly feelings that had 
 long existed between us. 
 
 "I carefully attended the lectures, taking notes as appeared 
 necessary. In Mathematics there were geometrical problems, 
 algebra, trigonometry (which latter subjects the lectures did 
 not reach till the terms of 1820). Mr Peacock gave me a copy 
 of Lacroix's Differential Calculus as translated by himself 
 
24 GEORGE BIDDELL AIRY. 
 
 and Herschel arid Babbage, and also a copy of their Ex- 
 amples. At this time, the usfe of Differential Calculus was 
 just prevailing over that of Fluxions (which I had learnt). I 
 betook myself to it with great industry. I also made myself 
 master of the theories of rectangular coordinates and some of 
 the differential processes applying to them, which only a few 
 of the best of the university mathematicians then wholly 
 possessed. In Classical subjects I read the Latin (Seneca's) 
 and English Hippolytus, Racine's Phedre (which my sister 
 translated for me), and all other books to which I was 
 referred, Aristotle, Longinus, Horace, Bentley, Dawes &c., 
 made verse translations of the Greek Hippolytus, and was 
 constantly on the watch to read what might be advan- 
 tageous. 
 
 " Early in December Mr Hustler sent for me to say that 
 one of the Company of Fishmongers, Mr R. Sharp, had given 
 to Mr John H. Smyth, M.P. for Norwich, the presentation to a 
 small exhibition of 20 a year, which Mr Smyth had placed 
 in Mr Hustler's hands, and which Mr Hustler immediately 
 conferred on me. This was my first step towards pecuniary 
 independence. I retained this exhibition till I became a 
 Fellow of the College. 
 
 "I stayed at Cambridge during part of the winter vacation, 
 and to avoid expense I quitted my lodgings and went for a 
 time into somebody's rooms in the Bishop's Hostel. (It is 
 customary for the tutors to place students in rooms when 
 their right owners are absent.) I took with me Thucydides 
 and all relating to it, and read the book, upon which the next 
 term's lectures were to be founded, very carefully. The latter 
 part of the vacation I spent at Bury, where I began with the 
 assistance of my sister to pick up a little French : as I per- 
 ceived that it was absolutely necessary for enabling me to 
 read modern mathematics. 
 
 " During a part of the time I employed myself in writing 
 out a paper on the geometrical interpretation of the alge- 
 braical expression V i. I think that the original suggestion 
 
FROM BIRTH TO B.A. DEGREE. 2$ 
 
 of perpendicular line came from some book (I do not re- 
 member clearly), and I worked it out in several instances 
 pretty well, especially in De Moivre's Theorem. I had 
 spoken of it in the preceding term to Mr Peacock and he 
 encouraged me to work it out. The date at the end is 1820, 
 January 21. When some time afterwards I spoke of it to 
 Mr Hustler, he disapproved of my employing my time on 
 such speculations. About the last day of January I returned 
 to Cambridge, taking up my abode in my former lodgings. I 
 shewed my paper on V I to Mr Peacock, who was much 
 pleased with it and shewed it to Mr Whewell and others. 
 
 " On February I I commenced two excellent customs. 
 The first was that I always had upon my table a quire of 
 large-sized scribbling-paper sewn together : and upon this 
 paper everything was entered : translations into Latin and 
 out of Greek, mathematical problems, memoranda of every 
 kind (the latter transferred when necessary to the subsequent 
 pages), and generally with the date of the day. This is a 
 most valuable custom. The other was this : as I perceived 
 that to write Latin prose well would be useful to me, I wrote 
 a translation of English into Latin every day. However 
 much pressed I might be with other business, I endeavoured 
 to write at least three or four words, but if possible I wrote a 
 good many sentences. 
 
 " I may fix upon this as the time when my daily habits 
 were settled in the form in which they continued for several 
 years. I rose in time for the chapel service at 7. It was the 
 College regulation that every student should attend Chapel 
 four mornings and four evenings (Sunday being one of each) 
 in every week : and in this I never failed. After chapel 
 service I came to my lodgings and breakfasted. At 9 I went 
 to College lectures, which lasted to n. Most of my con- 
 temporaries, being intended for the Church, attended also 
 divinity lectures : but I never did. I then returned, put my 
 lecture notes in order, wrote my piece of Latin prose, and 
 then employed myself on the subject which I was reading for 
 
26 GEORGE BIDDELL AIRY. 
 
 the time : usually taking mathematics at this hour. At 2 or 
 a little sooner I went out for a long walk, usually 4 or 5 
 miles into the country: sometimes if I found companions I 
 rowed on the Cam (a practice acquired rather later). A little 
 before 4 I returned, and at 4 went to College Hall. After 
 dinner I lounged till evening chapel time, ^ past 5, and 
 returning about 6 I then had tea. Then I read quietly, 
 usually a classical subject, till 1 1 ; and I never, even in the 
 times when I might seem most severely pressed, sat up later. 
 " From this time to the close of the annual examination 
 (beginning of June) I remained at Cambridge, stopping there 
 through the Easter Vacation. The subjects of the mathe- 
 matical lectures were ordinary algebra and trigonometry : but 
 Mr Peacock always had some private problems of a higher 
 class for me, and saw me I believe every day. The subjects 
 of the Classical lectures were, the termination of Hippolytus, 
 the book of Thucydides and the oration of Cicero. In 
 mathematics I read Whewell's Mechanics, then just published 
 (the first innovation made in the Cambridge system of 
 Physical Sciences for many years) : and I find in my scrib- 
 bling-paper notes, integrals, central forces, Finite Differences, 
 steam-engine constructions and powers, plans of bridges, 
 spherical trigonometry, optical calculations relating to the 
 achromatism of eye-pieces and achromatic object-glasses with 
 lenses separated, mechanical problems, Transit of Venus, 
 various problems in geometrical astronomy (I think it was at 
 this time that Mr Peacock had given me a copy of Wood- 
 house's Astronomy 1st Edition), the rainbow, plans for anemo- 
 meter and for a wind-pumping machine, clearing lunars, &c., 
 with a great number of geometrical problems. I remark that 
 my ideas on the Differential Calculus had not acquired on 
 some important points the severe accuracy which they acquired 
 in a few months. In Classics I read the Persae of ^Eschylus, 
 Greek and Roman history very much (Mitford, Hooke, 
 Ferguson) and the books of Thucydides introductory to that 
 of the lecture subject (the 3rd): and attended to Chronology. 
 
FROM BIRTH TO B.A. DEGREE. 27 
 
 On the scribbling-paper are verse-translations from Euripides, 
 careful prose-translations from Thucydides, maps, notes on 
 points of grammar &c. I have also little MS. books with 
 abundant notes on all these subjects: I usually made a little 
 book when I pursued any subject in a regular way. 
 
 " On May 1st Mr Dobree, the head lecturer, sent for me to 
 say that he appointed me head-lecturer's Sizar for the next 
 year. The stipend of this office was 10, a sum upon which 
 I set considerable value in my anxiety for pecuniary inde- 
 pendence: but it was also gratifying to me as shewing the 
 way in which I was regarded by the College authorities. 
 
 "On Wednesday, May 24th, 1820, the examination began. 
 I was anxious about the result of the examination, but only 
 in such a degree as to make my conduct perfectly steady and 
 calm, and to prevent me from attempting any extraordinary 
 exertion. 
 
 " When the Classes were published the first Class of the 
 Freshman's Year (alphabetically arranged, as is the custom) 
 stood thus: Airy, Boileau, Childers, Drinkwater, Field, Iliff, 
 Malkin, Myers, Romilly, Strutt, Tate, Winning. It was soon 
 known however that I was first of the Class. It was 
 generally expected (and certainly by me) that, considering 
 how great a' preponderance the Classics were understood, in 
 the known system of the College, to have in determining the 
 order of merit, Field would be first. However the number of 
 marks which Field obtained was about 1700, and that which 
 I obtained about 1900. No other competitor, I believe, was 
 near us." In a letter to Airy from his College Tutor, 
 Mr J. D. Hustler, there is the following passage : " It is a 
 matter of extreme satisfaction to me that in the late exami- 
 nation you stood not only in the First Class but first of the 
 first. I trust that your future exertions and success will be 
 commensurate with this honourable beginning." 
 
 " Of the men whom I have named, Drinkwater (Bethune) 
 was afterwards Legal Member of the Supreme Court of 
 India, Field was afterwards Rector of Reepham, Romilly 
 
28 GEORGE BIDDELL AIRY. 
 
 (afterwards Lord Rorpilly) became Solicitor-General, Strutt 
 (afterwards Lord Belper) became M.P. for Derby and First 
 Commissioner of Railways, Tate was afterwards master of 
 Richmond Endowed School, Childers was the father of 
 Childers who was subsequently First Lord of the Admiralty. 
 
 " I returned to Bury immediately. While there, some 
 students (some of them men about to take their B.A. degree 
 at the next January) applied to me to take them as pupils, 
 but I declined. This year of my life enabled me to under- 
 stand how I stood among men. I returned to Cambridge 
 about July nth. As a general rule, undergraduates are not 
 allowed to reside in the University during the Long Vacation. 
 I believe that before I left, after the examination, I had made 
 out that I should be permitted to reside: or I wrote to Mr 
 Hustler. I applied to Mr Hustler to be lodged in rooms in 
 College : and was put, first into rooms in Bishop's Hostel, 
 and subsequently into rooms in the Great Court. 
 
 "The first affair that I had in College was one of disap- 
 pointment by no means deserving the importance which it 
 assumed in my thoughts. I had been entered a Sizar, but as 
 the list of Foundation Sizars was full, my dinners in Hall 
 were paid for. Some vacancies had arisen : and as these 
 were to be filled up in order of merit, I expected one : and in 
 my desire for pecuniary independence I wished for it very 
 earnestly. However, as in theory all of the first class were 
 equal, and as there were some Sizars in it senior in entrance 
 to me, they obtained places first : and I was not actually 
 appointed till after the next scholarship examination (Easter 
 1821). However a special arrangement was made, allowing 
 me (I forget whether others) to sit at the Foundation-Sizars' 
 table whenever any of the number was absent : and in conse- 
 quence I received practically nearly the full benefits. 
 
 " Mr Peacock, who was going out for the Vacation, allowed 
 me access to his books. I had also (by the assistance of 
 various Fellows, who all treated me with great kindness, 
 almost to a degree of respect) command of the University 
 
FROM BIRTH TO B.A. DEGREE. 29 
 
 Library and Trinity Library : and spent this Long Vacation, 
 like several others, very happily indeed. 
 
 "The only non-mathematical subjects of the next exami- 
 nation were The Gospel of St Luke 3 Paley's Evidences, and 
 Paley's Moral and Political Philosophy. Thus my time was 
 left more free to mathematics and to general classics than 
 last year. I now began a custom which I maintained for 
 some years. Generally I read mathematics in the morning, 
 and classics for lectures in the afternoon : but invariably I 
 began at to o'clock in the evening to read with the utmost 
 severity some standard classics (unconnected with the lec- 
 tures) and at 1 1 precisely I left off and went to bed. I con- 
 tinued my daily translations into Latin prose as before. 
 
 "On August 24th, 1820, Rosser, a man of my own year, 
 engaged me as private tutor, paying at the usual rate (14 
 for a part of the Vacation, and 14 for a term): and immedi- 
 ately afterwards his friend Bedingfield did the same. This 
 occupied two hours every day, and I felt that I was now com- 
 pletely earning my own living. I never received a penny 
 from my friends after this time. 
 
 " I find on my scribbling-paper various words which shew 
 that in reading Poisson I was struggling with French words. 
 There are also Finite Differences and their Calculus, Figure 
 of the Earth (force to the center), various Attractions (some 
 evidently referring to Maclaurin's), Integrals, Conic Sections, 
 Kepler's Problem, Analytical Geometry, D'Alembert's 
 Theorem, Spherical Aberration, Rotations round three axes 
 (apparently I had been reading Euler), Floating bodies, 
 Evolute of Ellipse, Newton's treatment of the Moon's Varia- 
 tion. I attempted to extract something from Vince's Astro- 
 nomy on the physical explanation of Precession : but in 
 despair of understanding it, and having made out an expla- 
 nation for myself by the motion round three axes, I put 
 together a little treatise (Sept. 10, 1820) which with some 
 corrections and additions was afterwards printed in my 
 Mathematical Tracts. On Sept. I4th I bought Woodhouse's 
 
30 GEORGE BIDDELL AIRY. 
 
 Physical Astronomy, .and this, was quite an epoch in my 
 mathematical knowledge. First, I was compelled by the 
 process of " changing the independent variable " to examine 
 severely the logic of the Differential Calculus. Secondly, I 
 was now able to enter on the Theory of Perturbations, which 
 for several years had been the desired land to me. 
 
 "At the Fellowship Election of Oct. ist, Sydney Walker 
 (among other persons) was elected Fellow. He then quitted 
 the rooms in which he had lived (almost the worst in the 
 College), and I immediately took them. They suited me 
 well and I lived very happily in them till I was elected 
 Scholar. They are small rooms above the middle staircase 
 on the south side of Neville's Court. (Mr Peacock's rooms 
 were on the same staircase.) I had access to the leads on 
 the roof of the building from one of my windows. This was 
 before the New Court was built : my best window looked 
 upon the garden of the College butler. 
 
 " I had brought to Cambridge the telescope which I had 
 made at Colchester, and about this time I had a stand made 
 by a carpenter at Cambridge : and I find repeated observa- 
 tions of Jupiter and Saturn made in this October term. 
 
 "Other mathematical subjects on my scribbling-paper are: 
 Geometrical Astronomy, Barometers (for elevations), Mac- 
 laurin's Figure of the Earth, Lagrange's Theorem, Integrals, 
 Differential Equations of the second order, Particular Solu- 
 tions. In general mathematics I had much discussion with 
 Atkinson (who was Senior Wrangler, January 1821), and in 
 Physics with Rosser, who was a friend of Sir Richard Phillips, 
 a vain objector to gravitation. In Classics I read ^Eschylus 
 and Herodotus. 
 
 "On October 5th I received notice from the Head Lecturer 
 to declaim in English with Winning. (This exercise consists 
 in preparing a controversial essay, learning it by heart, and 
 speaking it in Chapel after the Thursday evening's service.) 
 On October 6th we agreed on the subject, " Is natural differ- 
 ence to be ascribed to moral or to physical causes ? " I taking 
 
FROM BIRTH TO B.A. DEGREE. 31 
 
 the latter side. I spoke the declamation (reciting it without 
 missing a word) on October 25th. On October 26th I 
 received notice of Latin declamation with Myers : subject 
 agreed on, " Utrum civitati plus utilitatis an incommodi affe- 
 rant leges quae ad vitas privatorum hominum ordinandas 
 pertinent " ; I took the former. The declamation was recited 
 on November II, when a curious circumstance occurred. My 
 declamation was rather long : it was the first Saturday of 
 the term on which a declamation had been spoken : and it 
 was the day on which arrived the news of the withdrawal of 
 the Bill of Pains and Penalties against Queen Caroline. 
 (This trial had been going on through the summer, but I 
 knew little about it.) In consequence the impatience of the 
 undergraduates was very great, and there was such an uproar 
 of coughing &c. in the Chapel as probably was never known. 
 The Master (Dr Wordsworth, appointed in the beginning of 
 the summer on the death of Dr Mansell, and to whom I had 
 been indirectly introduced by Mrs Clarkson) and Tutors and 
 Deans tried in vain to stop the hubbub. However I went 
 on steadily to the end, not at all frightened. On the Monday 
 the Master sent for me to make a sort of apology in the 
 name of the authorities, and letters to the Tutors were read 
 at the Lectures, and on the whole the transaction was nowise 
 disagreeable to me. 
 
 "On the Commemoration Day, December I5th, I received 
 my Prize (Mitford's Greece) as First-Class man, after dinner 
 in the College Hall. After a short vacation spent at Bury 
 and Playford I returned to Cambridge, walking from Bury 
 on Jan. 22nd, 1821. During the next term I find in Mathe- 
 matics Partial Differential Equations, Tides, Sound, Calculus 
 of Variations, Composition of rotary motions, Motion in resist- 
 ing medium, Lhuillier's theorem, Brightness of an object as 
 seen through a medium with any possible law of refraction 
 (a good investigation), star-reductions, numerical calculations 
 connected with them, equilibrium of chain under centripetal 
 force (geometrically treated, as an improvement upon Whe- 
 
32 GEORGE BIDDELL AIRY. 
 
 well's algebraical method), investigation of the magnitude of 
 attractive forces of glass, &c., -required to produce refraction. 
 I forget about Mathematical Lectures ; but I have an impres- 
 sion that I regularly attended Mr Peacock's lectures, and 
 that he always set me some private problems. 
 
 " I attended Mr Evans's lectures on St Luke : and I find 
 many notes about the history of the Jews, Cerinthus and 
 various heresies, Paley's Moral Philosophy, Paley's Evidences, 
 and Biblical Maps : also speculations about ancient pronun- 
 ciations. 
 
 "For a week or more before the annual examination I was 
 perfectly lazy. The Classes of my year (Junior Sophs) were 
 not published till June 11. It was soon known that I was 
 first with 2000 marks, the next being Drinkwater with 1200 
 marks. After a short holiday at Bury and Playford I 
 returned to Cambridge on July i8th, 1821. My daily life 
 went on as usual. I find that in writing Latin I began 
 Cicero De Senectute (retranslating Melmoth's translation, 
 and comparing). Some time in the Long Vacation the names 
 of the Prizemen for Declamations were published : I was 
 disappointed that not one, English or Latin, was assigned 
 to me: but it was foolish, for my declamations were rather 
 trumpery. 
 
 "My former pupil, Rosser, came again on August I4th. 
 On August 29th Dr Blomfield (afterwards Bishop of London) 
 called, to engage me as Tutor to his brother George Beecher 
 Blomfield, and he commenced attendance on Sept. ist. With 
 these two pupils I finished at the end of the Long Vacation : 
 for the next three terms I had one pupil, Gibson, a New- 
 castle man, recommended by Mr Peacock, I believe, as a 
 personal friend (Mr Peacock being of Durham). 
 
 " The only classical subject appointed for the next exami- 
 nation was the 5th, 6th and /th Books of the Odyssey : the 
 mathematical subjects all the Applied Mathematics and New- 
 ton. There was to be however the Scholarship Examination 
 (Sizars being allowed to sit for Scholarships only in their 
 
FROM BIRTH TO B.A. DEGREE. 33 
 
 3rd year : and the Scholarship being a kind of little Fellow- 
 ship necessary to qualify for being a candidate for the real 
 Fellowship). 
 
 " When the October term began Mr Hustler, who usually 
 gave lectures in mathematics to his third-year pupils, said to 
 me that it was not worth my while to attend his lectures, and 
 he or Mr Peacock suggested that Drinkwater, Myers, and I 
 should attend the Questionists' examinations. The Ques- 
 tionists are those who are to take the degree of B.A. in the 
 next January : and it was customary, not to give them 
 lectures, but three times a week to examine them by setting 
 mathematical questions, as the best method of preparing for 
 the B.A. examination. Accordingly it was arranged that we 
 should attend the said examinations : but when we went the 
 Questionists of that year refused to attend. They were 
 reported to be a weak year, and we to be a strong one : and 
 they were disposed to take offence at us on any occasion. 
 From some of the scholars of our year who sat at table with 
 scholars of that year I heard that they distinguished us as 
 ' the impudent year,' ' the annus mirabilis,' &c. On this 
 occasion they pretended to believe that the plan of our 
 attendance at the Questionists' examinations had been sug- 
 gested by an undergraduate, and no explanation was of the 
 least use. So the Tutors agreed not to press the matter on 
 them : and instead of it, Drinkwater, Myers, and I went 
 three times a week to Mr Peacock's rooms, and he set us 
 questions. I think that this system was also continued during 
 the next two terms (ending in June 1822) or part of them, 
 but I am not certain. 
 
 "In August 1821 I copied out a MS. on Optics, I think 
 from Mr Whewell : on August 24th one on the Figure of the 
 Earth and Tides ; and at some other time one on the motion 
 of a body round two centers of force; both from Mr Whewell. 
 On my scribbling paper I find A problem on the vibrations 
 of a gig as depending on the horse's step (like that of a 
 pendulum whose support is disturbed), Maclaurin's Attrac- 
 
 A. B, 3 
 
34 GEORGE BIDDELL AIRY. 
 
 tions, Effect of separating the lenses of an achromatic object- 
 glass (suggested by my old ; "telescope), Barlow's theory of 
 numbers, and division of the circle into 17 parts, partial 
 differentials, theory of eye-pieces, epicycloids, Figure of 
 the Earth, Time of body in arc of parabola, Problem of 
 Sound, Tides, Refraction of Lens, including thickness, &c., 
 Ivory's paper on Equations, Achromatism of microscope, 
 Capillary Attraction, Motions of Fluids, Euler's principal 
 
 axes, Spherical pendulum, Equation fr -^ = -^ , barometer, 
 
 Lunar Theory well worked out, ordinary differential equa- 
 tions, Calculus of Variations, Interpolations like Laplace's 
 for Comets, Kepler's theorem. In September I had my old 
 telescope mounted on a short tripod stand, and made experi- 
 ments on its adjustments. I was possessed of White's Ephe- 
 meris, and I find observations of Jupiter and Saturn in 
 October. I planned an engine for describing ellipses by the 
 
 A 
 
 polar equation ~ , and tried to make a micrometer 
 
 I + e cos 
 
 with silk threads converging to a point. Mr Cubitt called 
 on Oct. 4 and Nov. I ; he was engaged in erecting a tread- 
 mill at Cambridge Gaol, and had some thoughts of sending 
 plans for the Cambridge Observatory, the erection of which 
 was then proposed. On Nov. 19 I find that I had received 
 from Cubitt a Nautical Almanac, the first that I had. On 
 Dec. ill made some experiments with Drinkwater : I think 
 it was whirling a glass containing oil on water. In Classics 
 I was chiefly engaged upon Thucydides and Homer. On 
 October 6th I had a letter from Charles Musgrave, intro- 
 ducing Challis, who succeeded me in the Cambridge Obser- 
 vatory in 1836. 
 
 " At this time my poor afflicted father was suffering much 
 from a severe form of rheumatism or pain in the legs which 
 sometimes prevented him from going to bed for weeks 
 together. 
 
 "On the Commemoration Day, Dec. i8th, I received my 
 
FROM BIRTH TO B.A. DEGREE. 35 
 
 prize as first-class man in Hall again. The next day I 
 walked to Bury, and passed the winter vacation there and at 
 Playford. 
 
 "I returned to Cambridge on Jan. 24th, 1822. On Feb. 
 1 2th I kept my first Act, with great compliments from the 
 Moderator, and with a most unusually large attendance of 
 auditors. These disputations on mathematics, in Latin, are 
 now discontinued. On March 2Oth I kept a first Opponency 
 against Sandys. About this time I received Buckle, a Trinity 
 man of my own year, who was generally supposed to come 
 next after Drinkwater, as pupil. On my sheets I find inte- 
 grals and differential equations of every kind, astronomical 
 corrections (of which I prepared a book), chances, Englefield's 
 comets, investigation of the brightness within a rainbow, 
 proof of Clairaut's theorem in one case, metacentres, change 
 of independent variable applied to a complicated case, gene- 
 rating functions, principal axes. On Apr. 8th I intended to 
 write an account of my eye : I was then tormented with a 
 double image, I suppose from some disease of the stomach : 
 and on May 28th I find by a drawing of the appearance of a 
 lamp that the disease of my eye continued. 
 
 " On Feb. i ith I gave Mr Peacock a paper on the alteration 
 of the focal length of a telescope as directed with or against 
 the Earth's orbital motion (on the theory of emissions) which 
 was written out for reading to the Cambridge Philosophical 
 Society on Feb. 24th and 25th. [This Society I think was 
 then about a year old.] On Feb. I my MS. on Precession, 
 Solar Inequality, and Nutation, was made complete. 
 
 " The important examination for Scholarships was now 
 approaching. As I have said, this one opportunity only was 
 given to Sizars (Pensioners having always two opportunities 
 and sometimes three), and it is necessary to be a Scholar in 
 order to be competent to be a candidate for a Fellowship. 
 On Apr. loth I addressed my formal Latin letter to the 
 Seniors. There were 13 vacancies and 37 candidates. The 
 election took place on Apr. i8th, 1822. I was by much 
 
 32 
 
36 GEORGE BIDDELL AIRY. 
 
 the first (which I hardly expected) and was complimented by 
 the Master and others. Wrote ; the formal letter of thanks as 
 usual. I was now entitled to claim better rooms, and I took 
 the rooms on the ground floor on the East sicje of the Queen's 
 Gate of the Great Court. Even now I think of my quiet 
 residence in the little rooms above the staircase in Neville's 
 Court with great pleasure. I took possession of my new 
 rooms on May 27th. 
 
 "The Annual Examination began on May 3<Dth. The 
 Classes were published on June 5th, when my name was sepa- 
 rated from the rest by two lines. It was understood that the 
 second man was Drinkwater, and that my number of marks 
 was very nearly double of his. Having at this time been disap- 
 pointed of a proposed walking excursion into Derbyshire with 
 a college friend, who failed me at the last moment, I walked 
 to Bury and spent a short holiday there and at Playford. 
 
 "I returned to Cambridge on July I2th, 1822. I was 
 steadily busy during this Long Vacation, but by no means 
 oppressively so : indeed my time passed very happily. The 
 Scholars' Table is the only one in College at which the 
 regular possessors of the table are sure never to see a stranger, 
 and thus a sort of family intimacy grows up among the Scho- 
 lars. Moreover the Scholars feel themselves to be a privileged 
 class ' on the foundation/ and this feeling gives them a sort 
 of conceited happiness. It was the duty of Scholars by turns 
 to read Grace after the Fellows' dinner and supper, and at 
 this time (1848) I know it by heart. They also read the 
 Lessons in Chapel on week days : but as there was no daily 
 chapel-service during the summer vacation, I had not much 
 of this. In the intimacy of which I speak I became much 
 acquainted with Drinkwater, Buckle, Rothman, and Sutcliffe : 
 and we formed a knot at the table (first the Undergraduate 
 Scholars' table, and afterwards the Bachelor Scholars' table) 
 for several years. During this Vacation I had for pupils 
 Buckle and Gibson. 
 
 " I wrote my daily Latin as usual, beginning with the 
 
FROM BIRTH TO B.A. DEGREE. 37 
 
 retranslation of Cicero's Epistles, but I interrupted it from 
 Sept. 27th to Feb. 8th. I believe it was in this Vacation, or 
 in the October term, that I began every evening to read 
 Thucydides very carefully, as my notes are marked 1822 and 
 1823. On August 27 I find that I was reading Ovid's Fasti. 
 
 "In Mathematics I find the equation x+y=a, x? +y? = b y 
 Caustics, Calculus of Variations, Partial Differentials, Aberra- 
 tion of Light, Motions of Comets, various Optical construc- 
 tions computed with spherical aberrations, Particular Solu- 
 tions, Mechanics of Solid Bodies, Attractions of Shells, 
 Chances, Ivory's attraction-theorem, Lunar Theory (alge- 
 braical), Degrees across meridian, theoretical refraction, 
 Newton's 3rd Book, Investigation of the tides in a shallow 
 equatoreal canal, from which I found that there would be 
 low-water under the moon, metacentres, rotation of a solid 
 body round three axes, Attractions of Spheroids of variable 
 density, finite differences, and complete Figure of the Earth. 
 There is also a good deal of investigation of a mathematical 
 nature not connected with College studies, as musical chords, 
 organ-pipes, sketch for a computing machine (suggested by 
 the publications relating to Babbage's), sketch of machine for 
 solving equations. In August there is a plan of a MS. on the 
 Differential Calculus, which it appears I wrote then : one on 
 the Figure of the Earth written about August I5th; one on 
 Tides, Sept. 25th ; one on Newton's Principia with algebraical 
 additions, Nov. 1st. On Sept. 6th and loth there are Lunar 
 Distances observed with Rothman's Sextant and completely 
 worked out ; for these I prepared a printed skeleton form, I 
 believe my first. On December I3th there are references to 
 books on Geology (Conybeare and Phillips, and Parkinson) 
 which I was beginning to study. On July 27th, being the day 
 on which I completed my 2ist year, I carefully did nothing. 
 
 " Another subject partly occupied my thoughts, which, 
 though not (with reference to practical science) very wise, 
 yet gave me some Cambridge celebrity. In July 1819 I 
 had (as before mentioned) sketched a plan for constructing 
 
38 GEORGE BIDDELL AIRY. 
 
 reflecting telescopes with silvered glass, and had shewn it 
 afterwards to Mr Peacock. I "now completed the theory of 
 this construction by correcting the aberrations, spherical as 
 well as chromatic. On July I3th, 1822, I drew up a paper 
 about it for Mr Peacock. He approved it much, and in some 
 way communicated it to Mr (afterwards Sir John) Herschel. 
 I was soon after introduced to Herschel at a breakfast with 
 Mr Peacock : and he approved of the scheme generally. On 
 August 5th I drew up a complete mathematical paper for the 
 Cambridge Philosophical Society, which I entrusted to Mr 
 Peacock. The aberrations, both spherical and chromatic, are 
 here worked out very well. On Nov. 25th it was read at the 
 meeting of the Philosophical Society, and was afterwards 
 printed in their Transactions: this was my first printed 
 Memoir. Before this time however I had arranged to try 
 the scheme practically. Mr Peacock had engaged to bear 
 the expense, but I had no occasion to ask him. Partly (I 
 think) through Drinkwater, I communicated with an optician 
 named Bancks, in the Strand, who constructed the optical 
 part. I subsequently tried my telescope, but it would not 
 do. The fault, as I had not and have not the smallest doubt, 
 depends in some way on the crystallization of the mercury 
 silvering. It must have been about this time that I was 
 introduced to Mr (afterwards Sir James) South, at a party at 
 Mr Peacock's rooms. He advised me to write to Tulley, a 
 well-known practical optician, who made me some new 
 reflectors, &c. (so that I had two specimens, one Gregorian, 
 the other Cassegrainian). However the thing failed practi- 
 cally, and I was too busy ever after to try it again. 
 
 " During the October term I had no pupils. I kept my 
 second Act on Nov. 6 (opponents Hamilton, Rusby, Field), 
 and an Opponency against Jeffries on Nov. 7. I attended 
 the Questionists' Examinations. I seem to have lived a very 
 comfortable idle life. The Commemoration Day was Dec. 
 1 8th, when I received a Prize, and the next day I walked to 
 Bury. On Jan. 4th, 1823, I returned to Cambridge, and 
 
FROM BIRTH TO B.A. DEGREE. 39 
 
 until the B.A. Examination I read novels and played cards 
 more than at any other time in College. 
 
 "On Thursday, Jan. 9th, 1823, the preliminary classes, for 
 arrangement of details of the B.A. Examination, were pub- 
 lished. The first class, Airy, Drinkwater, Jeffries, Mason. 
 As far as I remember, the rule was then, that on certain days 
 the classes were grouped (in regard to identity of questions 
 
 given to each group) thus: ist, \ -r> , -j^-rl , &c., and on 
 
 certain other days thus: \ . 
 ' 2nd 
 
 ist 
 
 3rd 
 
 &c. On Saturday, 
 
 Jan. i ith, I paid fees. On Monday, Jan. I3th, the proceedings 
 of examination began by a breakfast in the Combination Room. 
 After this, Gibson gave me breakfast every day, and Buckle 
 gave me and some others a glass of wine after dinner. The 
 hours were sharp, the season a cold one, and no fire was 
 allowed in the Senate House where the Examination was 
 carried on (my place was in the East gallery), and altogether 
 it was a severe time. 
 
 " The course of Examination was as follows : 
 
 "Monday, Jan. I3th. 8 to 9, printed paper of questions 
 by Mr Hind (moderator); half-past 9 to II, questions given 
 orally ; I to 3, ditto ; 6 to 9, paper of problems at Mr Hig- 
 man's rooms. 
 
 " Tuesday, Jan. I4th. 8 to 9, Higman's paper; half-past 
 9 to n, questions given orally ; I to 3, ditto ; 6 to 9, paper of 
 problems in Sidney College Hall. 
 
 "Wednesday, Jan. I5th. Questions given orally 8 to 9 
 and I to 3, with paper of questions on Paley and Locke (one 
 question only in each was answered). 
 
 "Thursday, Jan. i6th. We went in at 9 and I, but there 
 seems to have been little serious examination. 
 
 " Friday, Jan. i/th. On this day the brackets or classes as 
 resulting from the examination were published, ist bracket 
 Airy, 2nd bracket Jeffries, 3rd bracket Drinkwater, Fisher, 
 Foley, Mason, Myers. 
 
40 GEORGE BIDDELL AIRY. 
 
 " On Saturday, Jan. i8th, the degrees were conferred in the 
 usual way. It had been arranged that my brother and sister 
 should come to see me take my degree of B.A., and I had 
 asked Gibson to conduct them to the Senate House Gallery : 
 but Mr Hawkes (a Trinity Fellow) found them and stationed 
 them at the upper end of the Senate House. After the 
 preliminary arrangements of papers at the Vice-Chancellor's 
 table, I, as Senior Wrangler, was led up first to receive the 
 degree, and rarely has the Senate House rung with such 
 applause as then filled it. For many minutes, after I was 
 brought in front of the Vice-Chancellor, it was impossible to 
 proceed with the ceremony on account of the uproar. I gave 
 notice to the Smith's Prize Electors of my intention to ' sit ' 
 for that prize, and dined at Rothman's rooms with Drink- 
 water, Buckle, and others. On Monday, Jan. 2Oth, I was 
 examined by Professor Woodhouse, for Smith's Prize, from 
 10 to i. I think that the only competitor was Jeffries. On 
 Tuesday I was examined by Prof. Turton, 10 to i, and on 
 Wednesday by Prof. Lax, 10 to I. On Thursday, Jan. 23rd, 
 I went to Bury by coach, on one of the coldest evenings that 
 I ever felt. 
 
 " Mr Peacock had once recommended me to sit for the 
 Chancellor's medal (Classical Prize). But he now seemed to 
 be cool in his advice, and I laid aside all thought of it." 
 
 It seems not out of place to insert here a copy of some 
 "Cambridge Reminiscences" written by Airy, which will 
 serve to explain the Acts and Opponencies referred to in 
 the previous narrative, and other matters. 
 
 THE ACTS. 
 
 The examination for B.A. degrees was preceded, in my 
 time, by keeping two Acts, in the Schools under the Univer- 
 sity Library: the second of them in the October term imme- 
 
FROM BIRTH TO B.A. DEGREE. 41 
 
 diately before the examination ; the first (I think) in the 
 October term of the preceding year. 
 
 These Acts were reliques of the Disputations of the 
 Middle Ages, which probably held a very important place 
 in the discipline of the University. (There seems to be 
 something like them in some of the Continental Universities.) 
 The presiding authority was one of the Moderators. I appre- 
 hend that the word " Moderator " signified " President," in 
 which sense it is still used in the Kirk of Scotland ; and that 
 it was peculiarly applied to the Presidency of the Disputa- 
 tions, the most important educational arrangement in the 
 University. The Moderator sent a summons to the " Re- 
 spondent" to submit three subjects for argument, and to 
 prepare to defend them on a given day : he also named three 
 Opponents. This and all the following proceedings were 
 conducted in Latin. For my Act of 1822, Nov. 6, I sub- 
 mitted the following subjects : 
 
 " Recte statuit Newtonus in Principiis suis Mathematicis, 
 libro primo, sectione undecima." 
 
 " Recte statuit Woodius de Iride." 
 
 " Recte statuit Paleius de Obligationibus." 
 
 The Opponents named to attack these assertions were 
 Hamilton of St John's, Rusby of St Catharine's, Field of 
 Trinity. It was customary for the Opponents to meet at tea 
 at the rooms of the Senior Opponent, in order to discuss and 
 arrange their arguments ; the Respondent was also invited, 
 but he was warned that he must depart as soon as tea would 
 be finished : then the three Opponents proceeded with their 
 occupation. As I have acted in both capacities, I am able to 
 say that the matter was transacted in an earnest and business- 
 like way. Indeed in the time preceding my own (I know not 
 whether in my own time) the assistance of a private tutor was 
 frequently engaged, and I remember hearing a senior M.A. 
 remark that my College Tutor (James D. Hustler) was the 
 best crammer for an Act in the University. 
 
 At the appointed time, the parties met in the Schools : 
 
42 GEORGE BIDDELL AIRY. 
 
 the Respondent first read a Latin Thesis on any subject (I 
 think I took some metaphysical subject), but nobody paid 
 any attention to it: then the Respondent read his first Dogma, 
 and the first Opponent produced an argument against it, in 
 Latin. After this there were repeated replies and rejoinders, 
 all in viva voce Latin, the Moderator sometimes interposing 
 a remark in Latin. When he considered that one argument 
 was disposed of, he called for another by the words " Probes 
 aliter." The arguments were sometimes shaped with con- 
 siderable ingenuity, and required a clear head in the Respon- 
 dent. When all was finished, the Moderator made a compli- 
 mentary remark to the Respondent and one to the first 
 Opponent (I forget whether to the second and third). In my 
 Respondency of 1822, November 6, the compliment was, 
 " Quaestiones tuas summo ingenio et acumine defendisti, et in 
 rebus mathematicis scientiam plane mirabilem ostendisti.' 
 In an Opponency (I forget when) the compliment was, 
 " Magno ingenio argumenta tua et construxisti et defen- 
 disti." 
 
 The Acts of the high men excited much interest among 
 the students. At my Acts the room was crowded with 
 undergraduates. 
 
 I imagine that, at a time somewhat distant, the mainte- 
 nance of the Acts was the only regulation by which the 
 University acted on the studies of the place. When the 
 Acts had been properly kept, license was given to the Father 
 of the College to present the undergraduate to the Vice- 
 Chancellor, who then solemnly admitted him "ad respon- 
 dendum Quaestioni." There is no appearance of collective 
 examination before this presentation : what the " Quaestio " 
 might be, I do not know. Still the undergraduate was not 
 B.A. The Quaestio however was finished and approved 
 before the day of a certain Congregation, and then the under- 
 graduate was declared to be "actualiter in artibus Bacca- 
 laureum." 
 
 Probably these regulations were found to be insufficient 
 
FROM BIRTH TO B.A. DEGREE. 43 
 
 for the control of education, and the January examination 
 was instituted. I conjecture this to have been at or shortly 
 before the date of the earliest Triposes recorded in the 
 Cambridge Calendar, 1748. 
 
 The increasing importance of the January examination 
 naturally diminished the value of the Acts in the eyes of the 
 undergraduates ; and, a few years after my M.A. degree, it 
 was found that the Opponents met, not for the purpose of 
 concealing their arguments from the Respondent, but for the 
 purpose of revealing them to him. This led to the entire 
 suppression of the system. The most active man in this 
 suppression was Mr Whewell : its date must have been near 
 to 1830. 
 
 The shape in which the arguments were delivered by an 
 Opponent, reading from a written paper, was, " Si (quoting 
 something from the Respondent's challenge), &c., &c. Cadit 
 Quaestio ; Sed (citing something else bearing on the subject 
 of discussion), Valet Consequentia ; Ergo (combining these 
 to prove some inaccuracy in the Respondent's challenge), 
 Valent Consequentia et Argumentum." Nobody pretended 
 to understand these mystical terminations. 
 
 Apparently the original idea was that several Acts should 
 be kept by each undergraduate ; for, to keep up the number 
 (as it seemed), each student had to gabble through a ridicu- 
 lous form " Si quaestiones tuae falsae sint, Cadit Quaestio : sed 
 quaestiones tuae falsae sunt, Ergo valent Consequentia et Argu- 
 mentum." I have forgotten time and place when this was 
 uttered. 
 
 THE SENATE-HOUSE EXAMINATION. 
 
 The Questionists, as the undergraduates preparing for 
 B.A. were called in the October term, were considered as a 
 separate body; collected at a separate table in Hall, attending 
 no lectures, but invited to attend a system of trial examina- 
 tions conducted by one of the Tutors or Assistant-Tutors. 
 
44 GEORGE BIDDELL AIRY. 
 
 From the Acts, from the annual College examinations, 
 and (I suppose) from enquiries' in the separate Colleges, the 
 Moderators acquired a general idea of the relative merits of 
 the candidates for honours. Guided by this, the candidates 
 were divided into six classes. The Moderators and Assistant 
 Examiners were provided each with a set of questions in 
 manuscript (no printed papers were used for Honours in the 
 Senate House ; in regard to the ol TroXXol I cannot say). On 
 the Monday on which the examination began, the Father of 
 the College received all the Questionists (I believe), at any 
 rate all the candidates for honours, at breakfast in the Combi- 
 nation Room at 8 o'clock, and marched them to the Senate 
 House. My place with other honour-men was in the East 
 Gallery. There one Examiner took charge of the 1st and 
 2nd classes united, another Examiner took the 3rd and 4th 
 classes united, and a third took the 5th and 6th united. On 
 Tuesday, one Examiner took the ist class alone, a second 
 took the 2nd and 3rd classes united, a third took the 4th and 
 5th classes united, and a fourth took the 6th class alone. On 
 Wednesday, Thursday, and Friday the changes were similar. 
 And, in all, the questioning was thus conducted. The 
 Examiner read from his manuscript the first question. 
 Those who could answer it proceeded to write out their 
 answers, and as soon as one had finished he gave the word 
 "Done"; then the Examiner read out his second question, 
 repeating it when necessary for the understanding by those 
 who took it up more lately. And so on. I think that the 
 same process was repeated in the afternoon ; but I do not 
 remember precisely. In this manner the Examination was 
 conducted through five days (Monday to Friday) with no 
 interruption except on Friday afternoon. It was principally, 
 perhaps entirely, bookwork. 
 
 But on two evenings there were printed papers of prob- 
 lems: and the examination in these was conducted just as 
 in the printed papers of the present day : but in the private 
 College Rooms of the Moderators. And there, wine and 
 
FROM BIRTH TO B.A. DEGREE. 45 
 
 other refreshments were offered to the Examinees. How 
 this singular custom began, I know not. 
 
 The order of merit was worked out on Friday afternoon 
 and evening, and was in some measure known through the 
 University late in the evening. I remember Mr Peacock 
 coming to a party of Examinees and giving information on 
 several places. I do not remember his mentioning mine 
 (though undoubtedly he did) but I distinctly remember his 
 giving the Wooden Spoon. On the Saturday morning at 
 8 o'clock the manuscript list was nailed to the door of the 
 Senate-House. The form of further proceedings in the pre- 
 sentation for degree (ad respondendum quaestioni) I imagine 
 has not been much altered. The kneeling before the Vice- 
 Chancellor and placing hands in the Vice-Chancellor's hands 
 were those of the old form of doing homage. 
 
 The form of examination which I have described was 
 complicated and perhaps troublesome, but I believe that it 
 was very efficient, possibly more so than the modern form 
 (established I suppose at the same time as the abolition of 
 the Acts). The proportion of questions now answered to the 
 whole number set is ridiculously small, and no accurate idea 
 of relative merit can be formed from them. 
 
 THE COLLEGE HALL. 
 
 When I went up in 1819, and for several years later, the 
 dinner was at J past 3. There was no supplementary dinner 
 for special demands. Boat-clubs I think were not invented, 
 even in a plain social way, till about 1824 or 1825; and not 
 in connection with the College till some years later. Some 
 of the senior Fellows spoke of the time when dinner was at 2, 
 and regretted the change. 
 
 There was supper in Hall at 9 o'clock : I have known it 
 to be attended by a few undergraduates when tired by ex- 
 aminations or by evening walks; and there were always some 
 seniors at the upper table: I have occasionally joined them, 
 
46 GEORGE BIDDELL AIRY. 
 
 and have had some very interesting conversations. The 
 supper was cold, but hot additions were made when re- 
 quired. 
 
 One little arrangement amused me, as shewing the 
 ecclesiastical character of the College. The Fasts of the 
 Church were to be strictly kept, and there was to be no 
 dinner in Hall. It was thus arranged. The evening chapel 
 service, which was usually at 5^ (I think), was held at 3; and 
 at 4 the ordinary full meal was served in Hall, but as it 
 followed the chapel attendance it was held to be supper; and 
 there was no subsequent meal. 
 
 There were no chairs whatever in Hall, except the single 
 chair of the vice-master at the head of the table on the dais 
 and that of the senior dean at the table next the East wall. 
 All others sat on benches. And I have heard allusions to a 
 ludicrous difficulty which occurred when some princesses (of 
 the Royal Family) dined in the Hall, and it was a great 
 puzzle how to get them to the right side of the benches. 
 
 The Sizars dined after all the rest; their dinner usually 
 began soon after 4. For the non-foundationists a separate 
 dinner was provided, as for pensioners. But for the founda- 
 tionists, the remains of the Fellows' dinner were brought 
 down ; and I think that this provision was generally preferred 
 to the other. 
 
 The dishes at all the tables of undergraduates were of 
 pewter, till a certain day when they were changed for porce- 
 lain. I cannot remember whether this was at the time when 
 they became Questionists (in the October Term), or at the 
 time when they were declared "actualiter esse in artibus 
 Baccalaureos " (in the Lent Term). 
 
 Up to the Questionist time the undergraduate Scholars 
 had no mixture whatever; they were the only pure table in 
 the Hall : and I looked on this as a matter very valuable for 
 the ultimate state of the College society. But in the October 
 term, those who were to proceed to B.A. were drafted into 
 the mixed body of Questionists : and they greatly disliked 
 
FROM BIRTH TO B.A. DEGREE. 47 
 
 the change. They continued so till the Lent Term, when 
 they, were formally invited by the Bachelor Scholars to join 
 the upper table. 
 
 MATHEMATICAL SUBJECTS OF STUDY AND EXAMINATION. 
 
 In the October Term 1819, the only books on Pure 
 Mathematics were: Euclid generally, Algebra by Dr Wood 
 (formerly Tutor, but in 1819 Master, of St John's College), 
 Vince's Fluxions and Dealtry's Fluxions, Woodhouse's and 
 other Trigonometries. Not a whisper passed through the 
 University generally on the subject of Differential Calculus ; 
 although some papers (subsequently much valued) on that 
 subject had been written by Mr Woodhouse, fellow of Caius 
 College ; but their style was repulsive, and they never took 
 hold of the University. Whewell's Mechanics (1819) contains 
 a few and easy applications of the Differential Calculus. 
 The books on applied Mathematics were Wood's Mechanics, 
 Whewell's Mechanics, Wood's Optics, Vince's Hydrostatics, 
 Vince's Astronomy, Woodhouse's Plane Astronomy (perhaps 
 rather later), The First Book of Newton's Principia: I do not 
 remember any others. These works were undoubtedly able; 
 and for the great proportion of University students going 
 into active life, I do not conceal my opinion that books con- 
 structed on the principles of those which I have cited were 
 more useful than those exclusively founded on the more 
 modern system. For those students who aimed at the 
 mastery of results more difficult and (in the intellectual sense) 
 more important, the older books were quite insufficient. 
 More aspiring students read, and generally with much care, 
 several parts of Newton's Principia, Book I., and also Book III. 
 (perhaps the noblest example of geometrical form of cosmical 
 theory that the world has seen). I remember some questions 
 from Book III. proposed in the Senate-House Examination 
 1823. 
 
48 GEORGE BIDDELL AIRY. 
 
 In the October term 1819, I went up to the University. 
 The works of Wood and Vince* which I have mentioned, still 
 occupied the lecture-rooms. But a great change was in 
 preparation for the University Course of Mathematics. 
 During the great Continental war, the intercourse between 
 men of science in England and in France had been most 
 insignificant. But in the autumn of 1819, three members of 
 the Senate (John Herschel, George Peacock, and Charles 
 Babbage) had entered into the mathematical society of Paris, 
 and brought away some of the works on Pure Mathematics 
 (especially those of Lacroix) and on Mechanics (principally 
 Poisson's). In 1820 they made a translation of Lacroix's 
 Differential Calculus ; and they prepared a volume of Ex- 
 amples of the Differential and Integral Calculus. These 
 were extensively studied : but the form of the College Ex- 
 aminations or the University Examinations was not, I think, 
 influenced by them in the winter 1820 1821 or the two 
 following terms. But in the winter 1821 1822 Peacock was 
 one of the Moderators ; and in the Senate-House Examina- 
 tion, January 1822, he boldly proposed a Paper of important 
 questions entirely in the Differential Calculus. This was 
 considered as establishing the new system in the University. 
 In January 1823, I think the two systems were mingled. 
 Though I was myself subject to that examination, I grieve to 
 say that I have forgotten much of the details, except that I 
 well remember that some of the questions referred to Newton, 
 Book III. on the Lunar Theory. To these I have already 
 alluded. 
 
 No other work occurs to me as worthy of mention, except 
 Woodhouse's Lunar Theory, entirely founded on the Dif- 
 ferential Calculus. The style of this book was not attractive, 
 and it was very little read. 
 
CHAPTER III. 
 
 AT TRINITY COLLEGE, CAMBRIDGE, FROM HIS TAKING 
 HIS B.A. DEGREE TO HIS TAKING CHARGE OF THE 
 CAMBRIDGE OBSERVATORY AS PLUMIAN PROFESSOR. 
 
 FROM JANUARY ISTH, 1823, TO MARCH ISTH, 1828. 
 
 "ON Jan. 3<Dth, 1823, I returned to Cambridge. I had 
 already heard that I had gained the 1st Smith's Prize, and 
 one of the first notifications to me on my return was that the 
 Walker's good-conduct prize of 10 was awarded to me. 
 
 " I remember that my return was not very pleasant, for our 
 table in hall was half occupied by a set of irregular men who 
 had lost terms and were obliged to reside somewhat longer in 
 order to receive the B.A. degree. But at the time of my 
 completing the B.A. degree (which is not till some weeks 
 after the examination and admission) I with the other com- 
 plete bachelors was duly invited to the table of the B.A. 
 scholars, and that annoyance ended. 
 
 "The liberation from undergraduate study left me at liberty 
 generally to pursue my own course (except so far as it was 
 influenced by the preparation for fellowship examination), 
 and also left me at liberty to earn more money, in the way 
 usual with the graduates, by taking undergraduate pupils. Mr 
 Peacock recommended me to take only four, which occupied 
 me four hours every day, and for each of them I received 
 20 guineas each term. My first pupils, for the Lent and 
 Easter terms, were Williamson (afterwards Head Master of 
 Westminster School), James Parker (afterwards Q.C. and 
 A. B. 4 
 
50 GEORGE BIDDELL AIRY. 
 
 Vice-Chancellor), Bissett, and Clinton of Caius. To all these 
 I had been engaged before taking my B.A. degree. 
 
 " I kept up classical subjects. I have a set of notes on the 
 nXouro? and Ne<e\a* of Aristophanes, finished on Mar. 1 5th, 
 1823, and I began my daily writing of Latin as usual on 
 Feb. 8th. In mathematics I worked very hard at Lunar and 
 Planetary Theories. I have two MS. books of Lunar Theory 
 to the 5th order of small quantities, which however answered 
 no purpose except that of making me perfectly familiar with 
 that subject. I worked well, upon my quires, the figure of 
 Saturn supposed homogeneous as affected by the attraction 
 of his ring, and the figure of the Earth as heterogeneous, and 
 the Calculus of Variations. I think it was now that I wrote 
 a MS. on constrained motion. 
 
 "On Mar. i;th, 1823, I was elected Fellow of the Cam- 
 bridge Philosophical Society. On May Qth a cast of my head 
 was taken for Dr Elliotson, an active phrenologist, by Deville, 
 a tradesman in the Strand. 
 
 " I had long thought that I should like to visit Scotland, 
 and on my once saying so to my mother, she (who had a 
 most kindly recollection of Alnwick) said in a few words that 
 she thought I could not do better. I had therefore for some 
 time past fully determined that as soon as I had sufficient 
 spare time and money enough I would go to Scotland. The 
 interval between the end of Easter Term and the usual 
 beginning with pupils in the Long Vacation offered sufficient 
 time, and I had now earned a little money, and I therefore 
 determined to go, and invited my sister to accompany me. 
 I had no private introductions, except one from James Parker 
 to Mr Reach, a writer of Inverness : some which Drinkwater 
 sent being too late. On May 2Oth we went by coach to 
 Stamford ; thence by Pontefract and Oulton to York, where 
 I saw the Cathedral, which then disappointed me, but I suppose 
 that we were tired with the night journey. Then by Newcastle 
 to Alnwick, where we stopped for the day to see my birth- 
 place. On May 24th to Edinburgh. On this journey I 
 
FROM B.A. DEGREE TO PLUMIAN PROFESSORSHIP. 51 
 
 remember well the stone walls between the fields, the place 
 (in Yorkshire) where for the first time in my life I saw rock, 
 the Hambleton, Kyloe, Cheviot and Pentland Hills, Arthur's 
 Seat, but still more strikingly the revolving Inch Keith Light. 
 At Edinburgh I hired a horse and gig for our journey in 
 Scotland, and we drove by Queensferry to Kinross (where for 
 the first time in my life I saw clouds on the hills, viz. on the 
 Lomond Hills), and so to Perth. Thence by Dunkeld and 
 Killicrankie to Blair Athol (the dreariness of the Drumochter 
 Pass made a strong impression on me), and by Aviemore 
 (where I saw snow on the mountains) to Inverness. Here we 
 received much kindness and attention from Mr Reach, and 
 after visiting the Falls of Foyers and other sights we went to 
 Fort Augustus and Fort William. We ascended Ben Nevis, 
 on which there was a great deal of snow, and visited the 
 vitrified fort in Glen Nevis. Then by Inverary to Tarbet, 
 and ascended Ben Lomond, from whence we had a magnifi- 
 cent view. We then passed by Loch Achray to Glasgow, 
 where we found James Parker's brother (his father, of the 
 house of Macinroy and Parker, being a wealthy merchant of 
 Glasgow). On June I5th to Mr Parker's house at Blochairn, 
 near Glasgow (on this day I heard Dr Chalmers preach), and 
 on the i /th went with the family by steamer (the first that I 
 had seen) to Fairly, near Largs. I returned the gig to Edin- 
 burgh, visited Arran and Bute, and we then went by coach to 
 Carlisle, and by Penrith to Keswick (by the old road : never 
 shall I forget the beauty of the approach to Keswick). After 
 visiting Ambleside and Kendal we returned to Cambridge by 
 way of Leeds, and posted to Bury on the 28th June. The 
 expense of this expedition was about 81. It opened a com- 
 pletely new world to me. 
 
 " I had little time to rest at Bury. In the preceding term 
 Drinkwater, Buckle, and myself, had engaged to go some- 
 where into the country with pupils during the Long Vacation 
 (as was customary with Cambridge men). Buckle however 
 changed his mind. Drinkwater went to look for a place, 
 
 42 
 
52 GEORGE BIDDELL AIRY. 
 
 fixed on Swansea, and engaged a house (called the Cambrian 
 Hotel, kept by a Captain Jenkins). On the morning of 
 July 2nd I left Bury for London and by mail coach to 
 Bristol. On the morning of July 3rd by steamer to Swansea, 
 and arrived late at night. I had then five pupils: Parker, 
 Harman Lewis (afterwards Professor in King's College, Lon- 
 don), Pierce Morton, Gibson, and Guest of Caius (afterwards 
 Master of the College). Drinkwater had four, viz. two 
 Malkins (from Bury), Elphinstone (afterwards M.P.), and 
 Parish (son of Professor Parish). We lived a hard-working 
 strange life. My pupils began with me at six in the morning : 
 I was myself reading busily. We lived completely enfamille, 
 with two men-servants besides the house establishment. One 
 of our first acts was to order a four-oared boat to be built, 
 fitted with a lug-sail : she was called the Granta of Swansea. 
 In the meantime we made sea excursions with boats borrowed 
 from ships in the port. On July 23rd, with a borrowed boat, 
 we went out when the sea was high, but soon found our boat 
 unmanageable, and at last got into a place where the sea was 
 breaking heavily over a shoal, and the two of the crew who 
 were nearest to me (A. Malkin and Lewis), one on each side, 
 were carried out : they were good swimmers and we recovered 
 them, though with some trouble : the breaker had passed 
 quite over my head : we gained the shore and the boat was 
 taken home by land. When our own boat was finished, we 
 had some most picturesque adventures at the Mumbles, 
 Aberavon, Caswell Bay, Ilfracombe, and Tenby. From all 
 this I learnt navigation pretty well. The mixture of hard 
 study and open-air exertion seemed to affect the health of 
 several of us (I was one) : we were covered with painful boils. 
 " My Latin-writing began again on July 25th : I have notes 
 on Demosthenes, Lucretius, and Greek History. In mathe- 
 matics I find Chances, Figure of the Earth with variable 
 density, Differential Equations, Partial Differentials, sketch 
 for an instrument for shewing refraction, and Optical instru- 
 ments with effects of chromatic aberration. In August there 
 
FROM B.A. DEGREE TO PLUMIAN PROFESSORSHIP. 53 
 
 occurred an absurd quarrel between the Fellows of Trinity 
 and the undergraduates, on the occasion of commencing the 
 building of King's Court, when the undergraduates were not 
 invited to wine, and absented themselves from the hall. 
 
 "There were vacant this year (1823) five fellowships in 
 Trinity College. In general, the B.A.'s of the first year are 
 not allowed to sit for fellowships : but this year it was 
 thought so probable that permission would be given, that on 
 Sept. 2nd Mr Higman, then appointed as Tutor to a third 
 ' side ' of the College, wrote to me to engage me as Assistant 
 Mathematical Tutor in the event of my being elected a 
 Fellow on Oct. ist, and I provisionally engaged myself. 
 About the same time I had written to Mr Peacock, who 
 recommended me to sit, and to Mr Whewell, who after con- 
 sultation with the Master (Dr Wordsworth), discouraged it. 
 As there was no absolute prohibition, I left Swansea on Sept. 
 nth (before my engagement to my pupils was quite finished) 
 and returned to Cambridge by Gloucester, Oxford, and 
 London. I gave in my name at the butteries as candidate for 
 fellowship, but was informed in a day or two that I should 
 not be allowed to sit. On Sept. ipth I walked to Bury. 
 
 " I walked back to Cambridge on Oct. i/th, 1823. During 
 this October term I had four pupils : Neate, Cankrein, Turner 
 (afterwards 2nd wrangler and Treasurer of Guy's Hospital), 
 and William Hervey (son of the Marquis of Bristol). In the 
 Lent term I had four (Neate, Cankrein, Turner, Clinton). 
 In the Easter term I had three (Neate, Cankrein, Turner). 
 
 " My daily writing of Latin commenced on Oct. 27th. In 
 November I began re-reading Sophocles with my usual care. 
 In mathematics I find investigations of Motion in a resisting 
 medium, Form of Saturn, Draft of a Paper about an instru- 
 ment for exhibiting the fundamental law of refraction (read 
 at the Philosophical Society by Mr Peacock on Nov. loth, 
 1823), Optics, Solid Geometry, Figure of the Earth with 
 variable density, and much about attractions. I also in this 
 term wrote a MS. on the Calculus of Variations, and one on 
 
54 GEORGE BIDDELL AIRY. 
 
 Wood's Algebra, 2nd and 4th parts. I have also notes of the 
 temperature of mines in Cornwall, something on the light of 
 oil-gas, and reminiscences of Swansea in a view of Oswick 
 Bay. In November I attended Professor Sedgwick's geo- 
 logical lectures. 
 
 "At some time in this term I had a letter from Mr South 
 (to whom I suppose I had written) regarding the difficulty of 
 my telescope : he was intimately acquainted with Tulley, and 
 I suppose that thus the matter had become more fully known 
 to him. He then enquired if I could visit him in the winter 
 vacation. I accordingly went from Bury, and was received 
 by him at his house in Blackman Street for a week or more 
 with great kindness. He introduced me to Sir Humphrey 
 Davy and many other London savans, and shewed me many 
 London sights and the Greenwich Observatory. I also had 
 a little practice with his own instruments. He was then on 
 intimate terms with Mr Herschel (afterwards Sir John Her- 
 schel), then living in London, who came occasionally to 
 observe double stars. This was the first time that I saw 
 practical astronomy. It seems that I borrowed his mountain 
 barometer. In the Lent term I wrote to him regarding the 
 deduction of the parallax of Mars, from a comparison of the 
 relative positions of Mars and 46 Leonis, as observed by him 
 and by Rumker at Paramatta. My working is on loose 
 papers. I see that I have worked out perfectly the interpo- 
 lations, the effects of uncertainty of longitude, &c., but I do 
 not see whether I have a final result. 
 
 " In Jan. 1824, at Playford, I was working on the effects of 
 separating the two lenses of an object-glass, and on the kind 
 of eye-piece which would be necessary : also on spherical 
 aberrations and Saturn's figure. On my quires at Cambridge 
 I was working on the effects of separating the object-glass 
 lenses, with the view of correcting the secondary spectrum : and 
 on Jan. 3ist I received some numbers (indices of refraction) 
 from Mr Herschel, and reference to Fraunhofer's numbers. 
 
 " About this time it was contemplated to add to the Royal 
 
FROM B.A. DEGREE TO PLUMIAN PROFESSORSHIP. 55 
 
 Observatory of Greenwich two assistants of superior educa- 
 tion. Whether this scheme was entertained by the Admiralty, 
 the Board of Longitude, or the Royal Society, I do not know. 
 Somehow (I think through Mr Peacock) a message from Mr 
 Herschel was conveyed to me, acquainting me of this, and 
 suggesting that I should be an excellent person for the prin- 
 cipal place. To procure information, I went to London on 
 Saturday, Feb. 7th, sleeping at Mr South's, to be present at 
 one of Sir Humphrey Davy's Saturday evening soirees (they 
 were then held every Saturday), and to enquire of Sir H. 
 Davy and Dr Young. When I found that succession to the 
 post of Astronomer Royal was not considered as distinctly a 
 consequence of it, I took it coolly, and returned the next 
 night. The whole proposal came to nothing. 
 
 " At this time I was engaged upon differential equations, 
 mountain barometer problem and determination of the height 
 of the Gogmagogs and several other points, investigations 
 connected with Laplace's calculus, spherical aberration in 
 different planes, geology (especially regarding Derbyshire, 
 which I proposed to visit), and much of optics. I wrote a 
 draft of my Paper on the figure of Saturn, and on Mar. I5th, 
 1824, it was read at the Philosophical Society under the title 
 of ' On the figure assumed by a fluid homogeneous mass, 
 whose particles are acted on by their mutual attraction, and 
 by small extraneous forces,' and is printed in their Memoirs. 
 I also wrote a draft of my Paper on Achromatic Eye-pieces, 
 and on May i^th, 1824, it was read at the Philosophical 
 Society under the title of 'On the Principles and Construc- 
 tion of the Achromatic Eye-pieces of Telescopes, and on the 
 Achromatism of Microscopes,' including also the effects of 
 separating the lenses of the object-glass. It is printed in 
 their Memoirs. 
 
 "Amongst miscellaneous matters I find that on Mar. 22nd 
 of this year I began regularly making extracts from the 
 books of the Book Society, a practice which I continued to 
 March 1826. On Mar. 27th, a very rainy day, I walked to 
 
56 GEORGE BIDDELL AIRY. 
 
 Bury to attend the funeral of my uncle William Biddell, near 
 Diss, and on Mar. 3Oth I walked back in rain and snow. On 
 Feb. 24th I dined with Cubitt in Cambridge. On May 2ist 
 I gave a certificate to Rogers (the assistant in Crosse's school, 
 and my instructor in mathematics), which my mother ampli- 
 fied much, and which I believe procured his election as 
 master of Walsall School. On June 23rd I went to Bury. 
 The speeches at Bury School, which I wished to attend, took 
 place next day." 
 
 At this point of his Autobiography the writer continues, 
 " Now came one of the most important occurrences in my 
 life." The important event in question was his acquaintance 
 with Richarda Smith, the lady who afterwards became his 
 wife. The courtship was a long one, and in the Auto- 
 biography there are various passages relating to it, all written 
 in the most natural and unaffected manner, but of somewhat 
 too private a nature for publication. It will therefore be 
 convenient to digress from the straight path of the narrative 
 in order to insert a short memoir of the lady who was destined 
 to influence his life and happiness in a most important degree. 
 
 Richarda Smith was the eldest daughter of the Rev. 
 Richard Smith, who had been a Fellow of Trinity College, 
 Cambridge, but was at this time Private Chaplain to the 
 Duke of Devonshire, and held the small living of Edensor, 
 near Chatsworth, in Derbyshire. He had a family of two 
 sons and seven daughters, whom he had brought up and 
 educated very carefully. Several of his daughters were 
 remarkable both for their beauty and accomplishments. 
 Richarda Smith was now in her 2Oth year, and the writer 
 of the Autobiography records that "at Matlock we received 
 great attention from Mr Chenery : in speaking of Mr Smith 
 I remember his saying that Mr Smith had a daughter whom 
 the Duke of Devonshire declared to be the most beautiful 
 girl he ever saw." This was before he had made the acquaint- 
 ance of the family. Airy was at this time on a walking 
 
FROM B.A. DEGREE TO PLUMIAN PROFESSORSHIP. 57 
 
 tour in Derbyshire with his brother William, and they were 
 received at Edensor by Mr Smith, to whom he had letters 
 of introduction. He seems to have fallen in love with Miss 
 Smith " at first sight," and within two days of first seeing her 
 he made her an offer of marriage. Neither his means nor his 
 prospects at that time permitted the least idea of an imme- 
 diate marriage, and Mr Smith would not hear of any engage- 
 ment. But he never had the least doubt as to the wisdom of 
 the choice that he had made : he worked steadily on, winning 
 fame and position, and recommending his suit from time to 
 time to Miss Smith as opportunity offered, and finally mar- 
 ried her, nearly six years after his first proposal. His con- 
 stancy had its reward, for he gained a most charming and 
 affectionate wife. As he records at the time of his marriage, 
 "My wife was aged between 25 and 26, but she scarcely 
 appeared more than 18 or 20. Her beauty and accomplish- 
 ments, her skill and fidelity in sketching, and above all her 
 exquisite singing of ballads, made a great sensation in Cam- 
 bridge." 
 
 Their married life lasted 45 years, but the last six years 
 were saddened by the partial paralysis and serious illness of 
 Lady Airy. The entire correspondence between them was 
 most carefully preserved, and is a record of a most happy 
 union. The letters were written during his numerous journeys 
 and excursions on business or pleasure, and it is evident that 
 his thoughts were with her from the moment of their parting. 
 Every opportunity of writing was seized with an energy and 
 avidity that shewed how much his heart was in the corre- 
 spondence. Nothing was too trivial or too important to 
 communicate to his wife, whether relating to family or business 
 matters. The letters on both sides are always full of affection 
 and sympathy, and are written in that spirit of confidence 
 which arises from a deep sense of the value and necessity of 
 mutual support in the troubles of life. And with his active 
 and varied employments and his numerous family there was 
 no lack of troubles. They were both of them simple-minded, 
 
58 GEORGE BIDDELL AIRY. 
 
 sensible, and practical people, and were very grateful for such 
 comforts and advantages as they were able to command, but 
 for nothing in comparison with their deep respect and affec- 
 tion for one another. 
 
 Both by natural ability and ' education she was well 
 qualified to enter into the pursuits of her husband, and in 
 many cases to assist him. She always welcomed her hus- 
 band's friends, and by her skill and attractive courtesy kept 
 them well together. She was an admirable letter-writer, and 
 in the midst of her numerous domestic distractions always 
 found time for the duties of correspondence. In conversation 
 she was very attractive, not so much from the wit or brilliancy 
 of her remarks as from the brightness and interest with which 
 she entered into the topics under discussion, and from the 
 unfailing grace and courtesy with which she attended to the 
 views of others. This was especially recognized by the 
 foreign astronomers and men of science who from time to 
 time stayed as guests at the Observatory and to whom she 
 acted as hostess. Although she was not an accomplished 
 linguist yet she was well able to express herself in French 
 and German, and her natural good sense and kindliness 
 placed her guests at their ease, and made them feel them- 
 selves (as indeed they were) welcomed and at home. 
 
 Her father, the Rev. Richard Smith, was a man of most 
 cultivated mind, and of the highest principles, with a keen 
 enjoyment of good society, which the confidence and friend- 
 ship of his patron the Duke of Devonshire amply secured to 
 him, both at Chatsworth and in London. He had a deep 
 attachment to his Alma Mater of Cambridge, and though not 
 himself a mathematician he had a great respect for the 
 science of mathematics and for eminent mathematicians. 
 During the long courtship already related Mr Smith con- 
 ceived the highest respect for Airy's character, as well as 
 for his great repute and attainments, and expressed his lively 
 satisfaction at his daughter's marriage. Thus on January 2Oth, 
 1830, he wrote to his intended son-in-law as follows : " I have 
 
FROM B.A. DEGREE TO PLUMIAN PROFESSORSHIP. 59 
 
 little else to say to you than that I continue with heartfelt 
 satisfaction to reflect on the important change about to take 
 place in my dear daughter's situation. A father must not 
 allow himself to dilate on such a subject : of course I feel 
 confident that you will have no reason to repent the irre- 
 vocable step you have taken, but from the manner in which 
 Richarda has been brought up, you will find such a helpmate 
 in her as a man of sense and affection would wish to have, 
 and that she is well prepared to meet the duties and trials 
 (for such must be met with) of domestic life with a firm and 
 cultivated mind, and the warm feelings of a kind heart. Her 
 habits are such as by no means to lead her to expensive 
 wishes, nor will you I trust ever find it necessary to neglect 
 those studies and pursuits upon which your reputation and 
 subsistence are chiefly founded, to seek for idle amusements 
 for your companion. I must indulge no further in speaking 
 of her, and have only at present to add that I commit in full 
 confidence into your hands the guardianship of my daughter's 
 happiness." And on April 5th, 1830, shortly after their 
 marriage, he wrote to his daughter thus : " If thinking of you 
 could supply your place amongst us you would have been 
 with us unceasingly, for we have all of us made you the 
 principal object of our thoughts and our talk since you left 
 us, and I travelled with you all your journey to your present 
 delightful home. We had all but one feeling of the purest 
 pleasure in the prospect of the true domestic comfort to 
 which we fully believe you to be now gone, and we rejoice 
 that all your endearing qualities will now be employed to 
 promote the happiness of one whom we think so worthy of 
 them as your dear husband, who has left us in the best 
 opinion of his good heart, as well as his enlightened and 
 sound understanding. His late stay with us has endeared 
 him to us all. Never did man enter into the married state 
 from more honourable motives, or from a heart more truly 
 seeking the genuine happiness of that state than Mr Airy, 
 and he will, I trust, find his reward in you from all that a 
 
60 GEORGE BIDDELL AIRY. 
 
 good wife can render to the best of husbands, and his hap- 
 piness be reflected on yourself." It would be difficult to find 
 letters of more genuine feeling and satisfaction, or more 
 eloquently expressed, than these. 
 
 The narrative of the Autobiography will now be resumed. 
 
 " I had been disappointed two years before of an expe- 
 dition to Derbyshire. I had wished still to make it, and my 
 brother wished to go : and we determined to make it this 
 year (1824). We were prepared with walking dresses and 
 knapsacks. I had well considered every detail of our route, 
 and was well provided with letters of introduction, including 
 one to the Rev. R. Smith of Edensor. On June 29th we 
 started by coach to Newmarket and walked through the Fens 
 by Ramsay to Peterborough. Then by Stamford and Ketton 
 quarries to Leicester and Derby. Here we were recognized 
 by a Mr Calvert, who had seen me take my degree, and he 
 invited us to breakfast, and employed himself in shewing us 
 several manufactories, &c. to which we had been denied 
 access when presenting ourselves unsupported. We then 
 went to Belper with an introduction from Mr Calvert to 
 Jedediah Strutt: saw the great cotton mills, and in the 
 evening walked to Matlock. Up to this time the country of 
 greatest interest was the region of the fens about Ramsay (a 
 most remarkable district), but now began beauty of scenery. 
 On July pth we walked by Rowsley and Haddon Hall over 
 the hills to Edensor, where we stayed till the I2th with 
 Mr Smith. We next visited Hathersage, Castleton, and 
 Marple (where I wished to see the canal aqueduct), and 
 went by coach to Manchester, and afterwards to Liverpool. 
 Here Dr Traill recommended us to -see the Pontycyssylte 
 Aqueduct, and we went by Chester and -Wrexham to 
 Rhuabon, saw the magnificent work, and proceeded to 
 Llangollen. Thence by Chester and Northwich (where we 
 descended a salt-mine) to Macclesfield. Then to the Ecton 
 mine (of which we saw but little) through Dovedale to 
 
FROM B.A. DEGREE TO PLUMIAN PROFESSORSHIP. 6 1 
 
 Ashbourn, and by coach to Derby. On July 24th to 
 Birmingham, where we found Mr Guest, lodged in his house, 
 and were joined by my pupil Guest. Here we were fully 
 employed in visiting the manufactures, and then went into 
 the iron country, where I descended a pit in the Staffordshire 
 Main. Thence by coach to Cambridge, where I stopped to 
 prepare for the Fellowship Examination. 
 
 " I had two pupils in this portion of the Long Vacation, 
 Turner and Dobbs. On August 2nd my writing of Latin 
 began regularly as before. My principal mathematics on the 
 quires are Optics. On August 25th I made experiments on 
 my left eye, with good measures, and on Aug. 26th ordered 
 a cylindrical lens of Peters, a silversmith in the town, which 
 I believe was never made. Subsequently, while at Playford, 
 I ordered cylindrical lenses of an artist named Fuller, living 
 at Ipswich, and these were completed in November, 1824. 
 
 " My letter to the Examiners, announcing my intention of 
 sitting for Fellowship (which like all other such documents is 
 preserved on my quires) was delivered on Sept. 2ist. The 
 Examination took place on Sept. 22nd and the two following 
 days. On Oct. 1st, 1824, at the usual hour of the morning, I 
 was elected Fellow. There were elected at the same time 
 T. B. Macaulay (afterwards Lord Macaulay), who was a year 
 senior to me in College, and I think Field of my own year. 
 I drew up my letter of acknowledgment to the Electors. On 
 Oct. 2nd at 9 in the morning I was admitted Fellow with 
 the usual ceremonies, and at 10 I called on the Electors with 
 my letter of acknowledgment. I immediately journeyed to 
 Derbyshire, paid a visit at Edensor, and returned by Sheffield. 
 
 "On Oct. nth (it having been understood with Mr 
 Higman that my engagement as Assistant Mathematical 
 Tutor stood) the Master sent for me to appoint me and to 
 say what was expected as duty of the office. He held out to 
 me the prospect of ultimately succeeding to the Tutorship, 
 and I told him that I hoped to be out of College before that 
 time. 
 
62 GEORGE BIDDELL AIRY. 
 
 " About this time the ' Athenaeum,' a club of a scientific 
 character, was established in London, and I was nominated 
 on it, but I declined . (Oct. I4th). In this year (1824) I 
 commenced account with a banker by placing 110 in the 
 hands of Messrs Mortlock and Co". On Oct. i6th I walked 
 to Bury, and after a single day's stay there returned to 
 Cambridge. 
 
 "On Oct. 23rd, 1824, 1 began my lectures as Mathematical 
 Assistant Tutor. I lectured the Senior Sophs and Junior 
 Sophs on Higman's side. The number of Senior Sophs was 
 21. Besides this I took part in the 'Examinations of the 
 Questionists,' a series of exercises for those who were to take 
 the Bachelor's degree in the next January. I examined in 
 Mechanics, Newton, and Optics. I had also as private 
 pupils Turner, Dobbs, and Cooper. I now ceased from the 
 exercise which I had followed with such regularity for 
 five years, namely that of daily writing Latin. In its stead 
 I engaged a French Master (Goussel) with whom I studied 
 French with reasonable assiduity for the three terms to 
 June, 1825. 
 
 " Among mathematical investigations I find : Theory of 
 the Moon's brightness, Motion of a body in an ellipse round 
 two centres of force, Various differential equations, Numerical 
 computation of sin TT from series, Numerical computation of 
 sines of various arcs to 18 decimals, Curvature of surfaces in 
 various directions, Generating functions, Problem of sound. 
 I began in the winter a Latin Essay as competing for the 
 Middle Bachelors' Prize, but did not proceed with it. I 
 afterwards wished that I had followed it up : but my time 
 was fully occupied. 
 
 "On Jan. 28th, 1825, I started for Edensor, where I paid 
 a visit, and returned on Feb. 2nd. On Feb. 4th I wrote to 
 Mr Clarkson, asking his advice about a profession or mode 
 of life (the cares of life were now beginning to press me 
 heavily, and continued to do so for several years). He re- 
 plied very kindly, but his answer amounted to nothing. 
 
FROM B.A. DEGREE TO PLUMIAN PROFESSORSHIP. 63 
 
 About the same time I had some conversation of the same 
 kind with Mr Peacock, which was equally fruitless. 
 
 " On Feb. 4th I have investigations of the density of light 
 near a caustic (on the theory of emissions). On Feb. 5th I 
 finished a Paper about the defect in my eye, which was com- 
 municated to the Cambridge Philosophical Society on Feb. 
 2 1 st. Mr Peacock or Mr Whewell had some time previously 
 applied to me to write a Paper on Trigonometry for the 
 Encyclopaedia Metropolitana, and I had been collecting some 
 materials (especially in regard to its history) at every visit to 
 London, where I read sometimes at the British Museum: 
 also in the Cambridge libraries. I began this Paper (roughly) 
 on Feb. 8th, and finished it on Mar. 3rd. The history of 
 which I speak, by some odd management of the Editors of 
 the Encyclopaedia, was never published. The MS. is now 
 amongst the MSS. of the Royal Observatory, Greenwich. 
 Other subjects on my quires are : Theory of musical con- 
 cords, many things relating to trigonometry and trigono- 
 metrical tables, achromatic eye-pieces, equation to the surface 
 bounding the rays that enter my left eye, experiments on 
 percussion. Also notes on Cumberland and Wales (I had 
 already proposed to myself to take a party of pupils in 
 the Long Vacation to Keswick), and notes on history and 
 geology. 
 
 "I had been in correspondence with Dr Malkin (master 
 of Bury School), who on Feb. 8th sent a certificate for my 
 brother William, whom I entered at Trinity on Peacock's 
 side. On Mar. 25th I changed my rooms, quitting those on 
 the ground-floor east side of Queen Mary's Gate for first- 
 floor rooms in Neville's Court, south side, the easternmost 
 rooms. In this term my lectures lasted from Apr. i8th to 
 May I4th. Apparently I had only the Senior Sophs, 19 in 
 number, and the same four pupils (Turner, Dobbs, Cooper, 
 Hovenden) as in the preceding term. The only scientific 
 subjects on which I find notes are, a Paper on the forms of 
 the Teeth of Wheels, communicated to the Philosophical 
 
64 GEORGE BIDDELL AIRY. 
 
 Society on May 2nd ; some notes about Musical Concords, 
 and some examination of a strange piece of Iceland Spar. 
 On Apr. 29th I was elected to the Northern Institution (of 
 Inverness) ; the first compliment that I received from an 
 extraneous body. 
 
 "On May I4th I have a most careful examination of my 
 money accounts, to see whether I can make an expedition 
 with my sister into Wales. My sister came to Cambridge, 
 and on Monday, May 23rd, 1825, we started for Wales, 
 equipped in the lightest way for a walking expedition. We 
 went by Birmingham to Shrewsbury : then to the Pontycys- 
 sylte Aqueduct and by various places to Bala, and thence by 
 Llanrwst to Conway. Here the suspension bridge was under 
 construction : the mole was made and the piers, but nothing 
 else. Then on to Bangor, where nine chains of the suspen- 
 sion bridge were in place, and so to Holyhead. Then by 
 Carnarvon to Bethgelert, ascending Snowdon by the way, 
 and in succession by Festiniog, Dolgelly, and Aberystwyth 
 to Hereford (the first time that I had visited it since my 
 father left it). From thence we went by coach to London, 
 and I went on to Cambridge on the 23rd of June. 
 
 " I had arranged to take a party of pupils to Keswick, 
 and to take my brother there. Mr Clarkson had provided 
 me with introductions to Mr Southey and Mr Wordsworth. 
 On Wednesday, June 29th, 1825, we started, and went by 
 Leicester, Sheffield, Leeds, and Kendal, to Keswick, calling 
 at Edensor on the way. My pupils were Cleasby, Marshman, 
 Clinton, Wigram, Tottenham, and M. Smith. At Keswick I 
 passed three months very happily. I saw Mr Southey's 
 family frequently, and Mr Wordsworth's occasionally. By 
 continual excursions in the neighbourhood, and by a few 
 excursions to places as distant as Bowness, Calder Bridge, 
 &c. (always climbing the intermediate mountains), I became 
 well acquainted with almost the whole of that beautiful 
 country, excepting some of the S. W. dales. A geological 
 hammer and a mountain barometer were very interesting 
 
FROM B.A. DEGREE TO PLUMIAN PROFESSORSHIP. 65 
 
 companions. I had plenty of work with my pupils : I worked 
 a little Lunar Theory, a little of Laplace's Equations, some- 
 thing of the Figure of the Earth, and I wrote out very care- 
 fully my Trigonometry for the Encyclopaedia Metropolitana. 
 I read a little of Machiavelli, and various books which I bor- 
 rowed of Mr Southey. On Friday, Sept 3Oth, my brother and 
 I left for Kendal, and after a stay of a few days at Edensor, 
 arrived at Cambridge on Oct. nth. 
 
 "On Oct. 2 1st my Lectures to the Junior Sophs began, 
 39 names, lasting to Dec. I3th. Those to the Senior Sophs, 
 16 names, Oct 2Qth to Dec. loth. I also examined Ques- 
 tionists as last year. I have notes about a Paper on the con- 
 nection of impact and pressure, read at the Philosophical 
 Society on Nov. I4th, but not printed, dipping-needle prob- 
 lems, curve described round three centres of force, barometer 
 observations, theory of the Figure of the Earth with variable 
 density, and effect on the Moon, correction to the Madras 
 pendulum, wedge with friction, spots seen in my eyes, density 
 of rays near a caustic. In this term I accomplished the pre- 
 paration of a volume of Mathematical Tracts on subjects 
 which, either from their absolute deficiency in the University 
 or from the unreadable form in which they had been pre- 
 sented, appeared to be wanted. The subjects of my Tracts 
 were, Lunar Theory (begun Oct. 26th, finished Nov. 1st), 
 Figure of the Earth (ist part finished Nov. i8th), Precession 
 and Nutation (my old MS. put in order), and the Calculus of 
 Variations. I applied, as is frequently done, to the Syndicate 
 of the University Press for assistance in publishing the work ; 
 and they agreed to give me paper and printing for 500 copies. 
 This notice was received from Professor Turton on Nov. 29th, 
 1825. It was probably also in this year that I drew up an 
 imperfect 'Review' of Coddington's Optics, a work which 
 deserved severe censure : my review was never finished. 
 
 " In the Long Vacation at Keswick I had six pupils at 
 42 each. In the October term I had Marshman and 
 Ogilby at 105 for three terms, and Dobbs at 75 for three 
 A. B. 5 
 
66 GEORGE BIDDELL AIRY. 
 
 terms. I had, at Mr Peacock's suggestion, raised my rate 
 from 60 to 100 guineas for three terms: this prevented some 
 from applying to me, and induced some to withdraw who had 
 been connected with me : but it .did me no real hurt, for 
 engrossment by pupils is the w6rst of all things that can 
 happen to a man who hopes to distinguish himself. On Dec. 
 1 7th I went to Bury, and returned to Cambridge on Jan. 
 30th, 1826. 
 
 "I have the attendance-bills of my Lectures to Senior 
 Sophs (16) from Feb. 3rd to Feb. 23rd, and to Freshmen (40) 
 from Feb. 2;th to Mar. 15. It would appear that I gave but 
 one college-lecture per day (my belief was that I always had 
 two). The tutor's stipend per term was 50. On my quires 
 I find, Investigations for the ellipticity of a heterogeneous 
 
 spheroid when the density is expressed by - (the remark- 
 able properties of which I believe I discovered entirely myself, 
 although they had been discovered by other persons), Theo- 
 retical Numbers for precession, nutation, &c., some investiga- 
 tions using Laplace's Y, hard work on the Figure of the 
 Earth to the 2nd order, ' Woodhouse's remaining apparatus/ 
 Notes about Lambton's and Kater's errors, Depolarization, 
 Notes of Papers on depolarization in the Phil. Trans., Mag- 
 netic Investigations for Lieut. Foster, Isochronous Oscilla- 
 tions in a resisting medium, Observations on a strange piece 
 of Iceland Spar. On Mar. /th forwarded Preface and Title 
 Page for my Mathematical Tracts. 
 
 " Some time in this term I began to think of the possi- 
 bility of observing the diminution of gravity in a deep mine, 
 and communicated with Whewell, who was disposed to join 
 in experiments. My first notion was simply to try the rate 
 of a clock, and the Ecton mine was first thought of. I made 
 enquiries about the Ecton mine through Mr Smith (of Eden- 
 sor), and visited the mine, but in the meantime Whewell had 
 made enquiries in London and found (principally from Dr 
 Paris) that the mine of Dolcoath near Camborne in Cornwall 
 
FROM B.A. DEGREE TO PLUMIAN PROFESSORSHIP. 67 
 
 would be a better place for the experiment. Dr Paris wrote 
 to me repeatedly, and ultimately we resolved on trying it 
 there. In my papers on Mar. 2ist are various investigations 
 about attractions in both mines. On Apr. 3rd I went to 
 London, principally to arrange about Dolcoath, and during 
 April and May I was engaged in correspondence with Sir H. 
 Davy (President of the Royal Society), Mr Herschel, and Dr 
 Young (Secretary of the Board of Longitude) about the loan 
 of instruments and pendulums. On Apr. 23rd I was prac- 
 tising pendulum-observations (by coincidence); and about 
 this time repeatedly practised transits with a small instru- 
 ment lent by Mr Sheepshanks (with whom my acquaintance 
 must have begun no long time before) which was erected 
 under a tent in the Fellows' Walks. On my quires I find 
 various schemes for graduating thermometers for pendulum 
 experiments. 
 
 " I find also Notes of examination of my brother William, 
 who had come to College last October ; and a great deal of 
 correspondence with my mother and sister and Mr Case, a 
 lawyer, about a troublesome business with Mr Cropley, an 
 old friend of G. Biddell, to whom my father had lent ^"500 
 and whose affairs were in Chancery. 
 
 " My lectures in this term were to the Junior Sophs from 
 Apr. loth to May I3th : they were six in number and not 
 very regular. On Apr. 28th I sent to Mawman the copy of 
 my Trigonometry for the Encyclopaedia Metropolitana, for 
 which I received 42. I received notice from the Press Syn- 
 dicate that the price of my Mathematical Tracts was fixed at 
 6s. 6d. : I sold the edition to Deighton for 70, and it was 
 immediately published. About this time I have letters from 
 Mr Herschel and Sir H. Davy about a Paper to be presented 
 to the Royal Society I suppose about the Figure of the 
 Earth to the 2nd order of ellipticity, which was read to the 
 Royal Society on June I5th. 
 
 "On Saturday, May I3th, 1826, I went to London on the 
 way to Dolcoath, and received four chronometers from the 
 
 52 
 
68 GEORGE BIDDELL AIRY. 
 
 Royal Observatory, Greenwich. I travelled by Devonport 
 and Falmouth to Camborne, where I arrived on May 2Oth 
 and dined at the count-house dinner at the mine. I was 
 accompanied by Ibbotson, who was engaged as a pupil, and 
 intended for an engineer. On May 24th Whewell arrived, 
 and we took a pendulum and clock down, and on the 3<Dth 
 commenced the observation of coincidences in earnest. This 
 work, with the changing of the pendulums, and sundry short 
 expeditions, occupied nearly three weeks. We had continued 
 the computation of our observations at every possible interval. 
 It is to be understood that we had one detached pendulum 
 swinging in front of a clock pendulum above, and another 
 similarly mounted below ; and that the clocks were compared 
 by chronometers compared above, carried down and com- 
 pared, compared before leaving, and brought up and com- 
 pared. The upper and lower pendulums had been inter- 
 changed. It was found now that the reliance on the steadi- 
 ness of the chronometers was too great ; and a new method 
 was devised, in which for each series the chronometers should 
 make four journeys and have four comparisons above and 
 two below. This arrangement commenced on the ipth June 
 and continued till the 26th. On the 26th we packed the lower 
 instruments, intending to compare the pendulum directly 
 with the upper one, and sent them up the shaft: when an 
 inexplicable occurrence stopped all proceedings. The basket 
 containing all the important instruments was brought up to 
 the surface (in my presence) on fire ; some of the instruments 
 had fallen out with their cases burning. Whether a super- 
 stitious miner had intentionally fired it, or whether the snuff 
 of a candle had been thrown into it, is not known. Our 
 labour was now rendered useless. On the 28th I packed up 
 what remained of instruments, left for Truro, and arrived at 
 Bury on July 1st. During our stay in Cornwall I had 
 attended a 'ticketing' or sale of ore at Camborne, and we 
 had made expeditions to the N. W. Coast, to Portreath and 
 Illogan, to Marazion and St Michael's Mount, and to Pen- 
 
FROM B.A. DEGREE TO PLUMIAN PROFESSORSHIP. 69 
 
 zance and the Land's End. On July 3rd I saw Mr Cropley 
 in Bury gaol, and went to Cambridge. On the 4th I was 
 admitted A.M., and on the 5th was admitted Major Fellow. 
 
 " I had engaged with four pupils to go to Orleans in this 
 Long Vacation : my brother William was also to go. One of 
 my pupils, Dobbs, did not join : the other three were Tinkler, 
 Ogilby, and Ibbotson. We left London on July 9th, and 
 travelled by Brighton, Dieppe, Rouen, and Paris to Orleans. 
 At Paris I saw Bouvard, Pouillet, Laplace and Arago. I had 
 introductions from Mr Peacock, Mr South, Mr Herschel, Dr 
 Young ; and from Professor Sedgwick to an English resi- 
 dent, Mr Underwood. On the I9th I was established in the 
 house of M. Lagarde, Protestant Minister. Here I received 
 my pupils. On the 28th I commenced Italian with an Italian 
 master : perhaps I might have done more prudently in adher- 
 ing to French, for I made no great progress. On Aug. 2nd 
 I saw a murderer guillotined in the Place Martroi. The 
 principal investigations on my quires are Investigations 
 about pendulums, Calculus of Variations, Notes for the 
 Figure of the Earth (Encyc. Metrop.) and commencement 
 of the article, steam-engine machinery, &c. I picked up 
 various French ballads, read various books, got copies of 
 the Marseillaise (this I was obliged to obtain rather secretly, 
 as the legitimist power under Charles X. was then at its 
 height) and other music, and particulars of farm wages for 
 Whewell and R. Jones. The summer was intensely hot, and 
 I believe that the heat and the work in Dolcoath had weak- 
 ened me a good deal. The family was the old clergyman, 
 his wife, his daughter, and finally his son. We lived together 
 very amicably. My brother lodged in a Cafe in the Place 
 Martroi ; the others in different families. I left Orleans on 
 Sept. 30th for Paris. Here I attended the Institut, and was 
 present at one of Ampere's Lectures. I arrived at Cambridge 
 on Oct. 1 4th. 
 
 "On Oct. i6th Whewell mentioned to me that the Lu- 
 casian Professorship would be immediately vacated by 
 
70 GEORGE BIDDELL AIRY. 
 
 Turton, and encouraged me to compete for it. Shortly after- 
 wards Mr Higman mentioned the Professorship, and Joshua 
 King (of Queens') spoke on the restriction which prevented 
 College tutors or Assistant tutors from holding the office. 
 About this time Mr Peacock rendered me a very important 
 service. As the emolument of the Lucasian Professorship 
 was only 99, and that of the Assistant Tutorship 150, I 
 had determined to withdraw from the candidature. But Mr 
 Peacock represented to me the advantage of position which 
 would be gained by obtaining the Professorship (which I then 
 instantly saw), and I continued to be a candidate. I wrote 
 letters to the Heads of Colleges (the electors) and canvassed 
 them personally. Only Dr Davy, the Master of Caius 
 College, at once promised me his vote. Dr French, Master 
 of Jesus College, was a candidate ; and several of the Heads 
 had promised him their votes. Mr Babbage, the third candi- 
 date, threatened legal proceedings, and Dr French withdrew. 
 The course was now open for Mr Babbage and me. 
 
 "In the meetings of the Philosophical Society a new 
 mode of proceeding was introduced this term. To enliven 
 the meetings, private members were requested to give oral 
 lectures. Mine was the second, I think, and I took for 
 subject The Machinery of the Steam Engines in the Cornish 
 mines, and especially of the Pumping Engines and Pumps. 
 It made an excellent lecture : the subjects were at that time 
 undescribed in books, and unknown to engineers in general 
 out of Cornwall. 
 
 "My College lectures seem to have been, Oct. 2ist to 
 Dec. I4th to 31 Junior Sophs, Dec. 4th to I2th to 12 Senior 
 Sophs. I assisted at the examinations of the Questionists. 
 I had no private pupils. On Nov. 26th I communicated to 
 the Cambridge Philosophical Society a Paper on the Theory 
 of Pendulums, Balances, and Escapements : and I find appli- 
 cations of Babbage's symbolism to an escapement which I 
 proposed. I have various investigations about the Earth, 
 supposed to project at middle latitudes above the elliptical 
 
FROM B.A. DEGREE TO PLUMIAN PROFESSORSHIP. 71 
 
 form. In November an account of the Dolcoath failure (by 
 Whewell) was given to the Royal Society. 
 
 "At length on Dec. 7th, 1826, the election to the Lucasian 
 Professorship took place: I was elected (I think unanimously) 
 and admitted. I believe that this gave great satisfaction to 
 the University in general. My uncle, Arthur Biddell, was in 
 Cambridge on that evening, and was the first of my friends 
 who heard of it. On the same page of my quires on which 
 this is mentioned, there is a great list of apparatus to be con- 
 structed for Lucasian Lectures, notes of experiments with 
 Atwood's Machine, &c. In December, correspondence with 
 Dollond about prisms. I immediately issued a printed notice 
 that I would give professorial lectures in the next Term. 
 
 "On Dec. I3th I have a letter from Mr Smith informing 
 me of the dangerous illness (fever) which had attacked nearly 
 every member of his family, Richarda worst of all. On Dec. 
 23rd I went to Bury. The affairs with Cropley had been 
 settled by the sale of his property under execution, and my 
 father did not lose much of his debt. But he had declined 
 much in body and mind, and now had strange hallucinations. 
 
 "The commencement of 1827 found me in a better posi- 
 tion (not in money but in prospects) than I had before stood 
 in: yet it was far from satisfactory. I had resigned my 
 Assistant Tutorship of 150 per annum together with the 
 prospect of succeeding to a Tutorship, and gained only the 
 Lucasian Professorship of 99 per annum. I had a great 
 aversion to entering the Church : and my lay fellowship 
 would expire in 7 years. My prospects in the law or other 
 professions might have been good if I could have waited : 
 but then I must have been in a state of starvation probably 
 for many years, and marriage would have been out of the 
 question : I much preferred a moderate income in no long 
 time, and I am sure that in this I judged rightly for my happi- 
 ness. I had now in some measure taken science as my line 
 (though not irrevocably), and I thought it best to work it 
 well, for a time at least, and wait for accidents. 
 
72 GEORGE BIDDELL AIRY. 
 
 " The acceptance of the Lucasian Professorship prevented 
 me from being pressed by Sedgwick (who was Proctor this 
 year) to take the office of moderator : which was a great 
 relief to me. As Lucasian Professor I was ipso facto 
 Member of the Board of Longittfde. A stipend of 100 a 
 year was attached to this, on condition of attending four 
 meetings : but I had good reason (from intimations by South 
 and other persons in London) for believing that this would 
 not last long. The fortnightly notices of the meetings of 
 the Board were given on Jan. i8th, Mar. 22nd, May 24th 
 and Oct. i8th. 
 
 "On Jan. 2nd, 1827, I came from London to Bury. I 
 found my father in a very declining state (the painful 
 rheumatism of some years had changed to ulcerations of the 
 legs, and he was otherwise helpless and had distressing hal- 
 lucinations). On Jan. 8th I walked to Cambridge. At both 
 places I was occupied in preparations for the Smith's Prize 
 Examination and for lectures (for the latter I obtained at 
 Bury gaol some numerical results about tread-mills). 
 
 " Of the Smith's Prize I was officially an Examiner : and 
 I determined to begin with what had never been done 
 before making the examination public, by printing the 
 papers of questions. The Prize is the highest Mathematical 
 honour in the University : the competitors are incepting 
 Bachelors of Arts after the examination for that Degree. 
 My day of examination (apparently) was Jan. 2ist. The 
 candidates were Turner, Cankrein, Cleasby, and Mr Gordon. 
 The first three had been my private pupils : Mr Gordon was 
 a Fellow-commoner of St Peter's College, and had just passed 
 the B.A. examination as Senior Wrangler, Turner being 
 second. My situation as Examiner was rather a delicate 
 one, and the more so as, when I came to examine the papers 
 of answers, Turner appeared distinctly the first. Late at 
 night I carried the papers to Whewell's rooms, and he on 
 inspection agreed with me. The other examiners (Professors 
 Lax and Woodhouse, Lowndean and Plumian Professors) 
 
FROM B.A. DEGREE TO PLUMIAN PROFESSORSHIP. 73 
 
 generally supported me : and Turner had the honour of First 
 Smith's Prize. 
 
 " On Jan. 3Oth my mother wrote, asking if I could see 
 Cropley in London, where he was imprisoned for contempt 
 of Chancery. I attended the meeting of the Board of 
 Longitude on Feb. ist, and afterwards visited Cropley in the 
 Fleet Prison. He died there, some time later. It was by 
 the sale of his effects under execution that my father's debt 
 was paid. 
 
 "On Feb. i$th I communicated to the Royal Society a 
 Paper on the correction of the Solar Tables from South's 
 observations. I believe that I had alluded to this at the 
 February meeting of the Board of Longitude, and that in 
 consequence Mr Pond, the Astronomer Royal, had been re- 
 quested to prepare the errors of the Sun's place from the 
 Greenwich observations : which were supplied some months 
 later. With the exception of South's Solar Errors, and 
 some investigations about dipping-needles, I do not find 
 anything going on but matters connected with my ap- 
 proaching lectures. There are bridges, trusses, and other 
 mechanical matters, theoretical and practical, without end. 
 Several tradesmen in Cambridge and London were well em- 
 ployed. On Feb. I3th I have a letter from Cubitt about 
 groins : I remember studying those of the Custom-house and 
 other places. On Feb. 2Oth my Syllabus of Lectures was 
 finished : this in subsequent years was greatly improved. I 
 applied to the Royal Society for the loan of Huyghens's 
 object-glass, but they declined to lend it. About this time I 
 find observations of the spectrum of Sirius. 
 
 " There had been no lectures on Experimental Philosophy 
 (Mechanics, Hydrostatics, Optics) for many years. The 
 University in general, I believe, looked with great satisfac- 
 tion to my vigorous beginning : still there was considerable 
 difficulty about it. There was no understood term for the 
 Lectures : no understood hour of the day : no understood 
 lecture room. I began this year in the Lent Term, but in 
 
74 GEORGE BIDDELL AIRY. 
 
 all subsequent years I took the Easter Term, mainly for the 
 chance of sunlight for the optical experiments, which I soon 
 made important. I could get no room but a private or 
 retiring room (not a regular lecture room) in the buildings at 
 the old Botanic Garden : in following years I had the room 
 under the University Library. The Lectures commenced on 
 some day in February 1827: I think that the number who 
 attended them was about 64. I remember very well that the 
 matter which I had prepared as an Introductory Lecture did 
 not last above half the time that I had expected, but I 
 managed very well to fill up the hour. On another occasion 
 I was so ill-prepared that I had contemplated giving notice 
 that I was unable to complete the hour's lecture, but I saw in 
 the front row some strangers, introduced by some of my 
 regular attendants, very busy in taking notes, and as it was 
 evident that a break-down now would not do, I silently 
 exerted myself to think of something, and made a very good 
 lecture. 
 
 "On Mar. ist, as official examiner, I received notices 
 from 14 candidates for Bell's Scholarships, and prepared my 
 Paper of questions. I do not remember my day of examina- 
 tion ; but I had all the answers to all the examiners' ques- 
 tions in my hands, when on Mar. 2/th I received notice that 
 my father had died the preceding evening. This stopped my 
 Lectures : they were concluded in the next term. I think 
 that I had only Mechanics and imperfect Optics this term, 
 no Hydrostatics; and that the resumed Lectures were princi- 
 pally Optical. They terminated about May I4th. 
 
 " With my brother I at once went to Bury to attend my 
 father's funeral. He was buried on Mar. 3ist, 1827, in the 
 churchyard of Little Whelnetham, on the north side of the 
 church. Shortly afterwards I went to London, and on Apr. 
 5th I attended a meeting of the Board of Longitude, at which 
 Herschel produced a Paper regarding improvements of the 
 Nautical Almanac. Herschel and I were in fact the leaders 
 of the reforming party in the Board of Longitude : Dr Young 
 
FROM B.A. DEGREE TO PLUMIAN PROFESSORSHIP. 75 
 
 the Secretary resisted change as much as possible. After the 
 meeting I went to Cambridge. I find then calculations of 
 achromatic eye-pieces for a very nice model with silk threads 
 of various colours which I made with my own hands for my 
 optical lectures. 
 
 " On Apr. 7th Herschel wrote to me that the Professor- 
 ship held by Dr Brinkley (then appointed Bishop of Cloyne) 
 at Dublin would be vacant, and recommended it to my 
 notice, and sent me some introductions. I reached Dublin 
 on Apr. 1 5th, where I was received with great kindness by 
 Dr Brinkley and Dr MacDonnell (afterwards Provost). I 
 there met the then Provost Dr Bartholomew Lloyd, Dr 
 Lardner, Mr Hamilton (afterwards Sir W. R. Hamilton) and 
 others. In a few days I found that they greatly desired to 
 appoint Hamilton if possible (they did in fact overcome some 
 difficulties and appoint him in a few months), and that they 
 would not make such an augmentation as would induce me 
 to offer myself as a candidate, and I withdrew. I have 
 always remembered with gratitude Dr MacDonnell's conduct, 
 in carefully putting me on a fair footing in this matter. I 
 returned by Holyhead, and arrived at Birmingham on Apr. 
 23rd. While waiting there and looking over some papers 
 relating to the spherical aberration of eye-pieces, in which I 
 had been stopped some time by a geometrical difficulty, I did 
 in the coffee-room of a hotel overcome the difficulty; and 
 this was the foundation of a capital paper on the Spherical 
 Aberration of Eye-pieces. This paper was afterwards pre- 
 sented to the Cambridge Philosophical Society. 
 
 " About this time a circumstance occurred of a disagree- 
 able nature, which however did not much disconcert me. 
 Mr Ivory, who had a good many years before made himself 
 favourably known as a mathematician, especially by his 
 acquaintance with Laplace's peculiar analysis, had adopted 
 (as not unfrequently happens) some singular hydrostatical 
 theories. In my last Paper on the Figure of the Earth, I 
 had said that I could not receive one of his equations. In 
 
76 GEORGE BIDDELL AIRY. 
 
 the Philosophical Magazine of May he attacked me for this 
 with great heat. On May 8th I wrote an answer, and I 
 think it soon became known that I was not to be attacked 
 with impunity. 
 
 " Long before this time there 1 had been some proposal 
 about an excursion to the Lake District with my sister, and 
 I now arranged to carry it out. On May 23rd I went to 
 Bury and on to Playford : while there I sketched the Cum- 
 berland excursion. On June 5th I went to London, I believe 
 to the Visitation of the Greenwich Observatory to which I 
 was invited. I also attended the meeting of the Board of 
 Longitude. I think it was here that Pond's Errors of the 
 Sun's place in the Nautical Almanac from Greenwich Obser- 
 vations were produced. On June /th I went by coach to 
 Rugby, where I met my sister, and we travelled to Edensor. 
 We made a number of excursions in Derbyshire, and then 
 passed on by Penrith to Keswick, where we arrived on June 
 22nd. From Keswick we made many excursions in the 
 Lake District, visited Mr Sou they and Mr Wordsworth, 
 descended a coal mine at Whitehaven, and returned to 
 Edensor by the way of Ambleside, Kendal, and Manchester. 
 With sundry excursions in Derbyshire our trip ended, and 
 we returned to Cambridge on the 2ist July. 
 
 " During this Long Vacation I had one private pupil, 
 Crawford, the only pupil this year, and the last that I ever 
 had. At this time there is on my papers an infinity of opti- 
 cal investigations : also a plan of an eye-piece with a concave 
 lens to destroy certain aberrations. On Aug. 2Oth I went to 
 Woodford to see Meosrs Gilbert's optical works. From Aug. 
 1 3th I had been preparing for the discussion of the Green- 
 wich Solar Errors, and I had a man at work in my rooms, 
 engaged on the calculation of the Errors. I wrote to Bouvard 
 at Paris for observations of the sun, but he recommended me 
 to wait for the Tables which Bessel was preparing. I was 
 busy too about my Lectures : on Sept. 2Qth I have a set of 
 plans of printing presses from Hansard the printer (who in a 
 
FROM B.A. DEGREE TO PLUMIAN PROFESSORSHIP. 77 
 
 visit to Cambridge had found me making enquiries about 
 them), and I corresponded with Messrs Gilbert about optical 
 constructions, and with W. and S. Jones, Eastons, and others 
 about pumps, hydraulic rams, &c. On Sept. 25th occurred 
 a very magnificent Aurora Borealis. 
 
 " I do not find when the investigation of Corrections of 
 Solar Elements was finished, or when my Extracts from 
 Burckhardt, Connaissance des Temps 1816, were made. But 
 these led me to suspect an unknown inequality in the Sun's 
 motion. On Sept. 27th and 28th I find the first suspicions of 
 an inequality depending on 8 x mean longitude of Venus 
 13 x mean longitude of Earth. The thing appeared so 
 promising that I commenced the investigation of the pertur- 
 bation related to this term, and continued it (a very laborious 
 work) as fast as I was able, though with various interruptions, 
 which in fact were necessary to keep up my spirits. On 
 Oct. 3<Dth I went to London for the Board of Longitude 
 meeting. Here I exhibited the results of my Sun investiga- 
 tions, and urged the correction of the elements used in the 
 Nautical Almanac. Dr Young objected, and proposed that 
 Bouvard should be consulted. Professor Woodhouse, the 
 Plumian Professor, was present, and behaved so captiously 
 that some members met afterwards to consider how order 
 could be maintained. I believe it was during this visit to 
 London that I took measures of Hammersmith Suspension 
 Bridge for an intended Lecture-model. Frequently, but not 
 always, when in London, I resided at the house of Mr Sheep- 
 shanks and his sister Miss Sheepshanks, 30 Woburn Place. 
 My quires, at this time, abound with suggestions for lectures 
 and examinations. 
 
 " On some day about the end of November or beginning 
 of December 1827, when I was walking with Mr Peacock 
 near the outside gate of the Trinity Walks, on some mention 
 of Woodhouse, the Plumian Professor, Mr Peacock said that 
 he was never likely to rise into activity again (or using some 
 expression importing mortal illness). Instantly there had 
 
78 GEORGE BIDDELL AIRY. 
 
 passed through my mind the certainty of my succeeding him, 
 the good position in which I stood towards the University, 
 the probability of that position being improved by improved 
 lectures, &c., &c., and J>y increased reputation from the 
 matters in which I was now engaged, the power of thus 
 commanding an increase of income. I should then have, 
 independent of my Fellowship, some competent, income, and 
 a house over my head. I was quite aware that some time 
 might elapse, but now for the first time I saw my way clearly. 
 The care of the Observatory had been for two or three years 
 attached to the Plumian Professorship. A Grace was imme- 
 diately prepared, entrusting the temporary care of the Obser- 
 vatory to Dr French, to me, Mr Catton, Mr Sheepshanks, 
 and Mr King (afterwards Master of Queens' College). On 
 Dec. 6th I have a note from Mr King about going to the 
 Observatory. 
 
 " On Dec. 6th my Paper on corrections of the elements of 
 the Solar Tables was presented to the Royal Society. On 
 Dec. Qth, at I h. 4 m. a.m. (Sunday morning), I arrived at the 
 result of my calculations of the new inequality. I had gone 
 through some fluctuations of feeling. Usually the important 
 part of an inequality of this kind depends entirely on the 
 eccentricities of the orbits, but it so happened that from the 
 positions of the axes of the orbits, &c., these terms very 
 nearly destroyed each other. After this came the considera- 
 tion of inclinations of orbits ; and here were sensible terms 
 which were not destroyed. Finally I arrived at the result 
 that the inequality would be about 3"; just such a magnitude 
 as was required. I slipped this into Whewell's door. This 
 is, to the time of writing (1853), the last improvement of any 
 importance in the Solar Theory. Some little remaining work 
 went on to Dec. I4th, and then, being thoroughly tired, I laid 
 by the work for revision at some future time. I however 
 added a Postscript to my Royal Society Paper on Solar 
 Errors, notifying this result. 
 
 " On Dec. iQth I went to Bury. While there I heard from 
 
FROM B.A. DEGREE TO PLUMIAN PROFESSORSHIP. 79 
 
 Whewell that Woodhouse was dead. I returned to Cam- 
 bridge and immediately made known that I was a candidate 
 for the now vacant Plumian Professorship. Of miscellaneous 
 scientific business, I find that on Oct. I3th Professor Barlow 
 of Woolwich prepared a memorial to the Board of Longitude 
 concerning his fluid telescope (which I had seen at Woodford), 
 which was considered on Nov. 1st, and I had some corre- 
 spondence with him in December. In June and August my 
 Trigonometry was printing. 
 
 "On Jan. 5th, 1828, I came from London. It seems that 
 I had been speculating truly ' without book ' on perturba- 
 tions of planetary elements, for on Jan. i/th and i8th I wrote 
 a Paper on a supposed error of Laplace, and just at the end 
 I discovered that he was quite right : I folded up the Paper 
 and marked it 'A Lesson/ I set two papers of questions 
 for Smith's Prizes (there being a deficiency of one Examiner, 
 viz. the Plumian Professor). 
 
 "Before the beginning of 1828 Whewell and I had deter- 
 mined on repeating the Dolcoath experiments. On Jan. 8th 
 I have a letter from Davies Gilbert (then President of the 
 Royal Society) congratulating me upon the Solar Theory, 
 and alluding to our intended summer's visit to Cornwall. 
 We had somehow applied to the Board of Longitude for 
 pendulums, but Dr Young wished to delay them, having with 
 Capt. Basil Hall concocted a scheme for making Lieut. 
 Foster do all the work : Whewell and I were indignant at 
 this, and no more was said about it. On Jan. 24th Dr Young, 
 in giving notice of the Board of Longitude meeting, informs 
 me that the clocks and pendulums are ready. 
 
 " I had made known that I was a candidate for the 
 Plumian Professorship, and nobody thought it worth while 
 to oppose me. One person at least (Earnshaw) had intended 
 to compete, but he called on me to make certain that I was a 
 candidate, and immediately withdrew. I went on in quality 
 of Syndic for the care of the Observatory, ingrafting myself 
 into it. But meantime I told everybody that the salary 
 
80 GEORGE BIDDELL AIRY. 
 
 (about ^"300) was not sufficient for me ; and on Jan. 2Oth I 
 drafted a manifesto or application to the University for an 
 increase of salary. The day of election to the Professorship 
 was Feb. 6th. As I was officially (as Lucasian Professor) an 
 elector, I was present, and T explained to the electors that I 
 could not undertake the responsibility of the Observatory 
 without augmentation of income, and that I requested their 
 express sanction to my application to the University for that 
 purpose. They agreed to this generally, and I was elected. 
 I went to London immediately to attend a meeting of the 
 Board of Longitude and returned on Feb. 8th. On Feb. I5th 
 I began my Lectures (which, this year, included Mechanics, 
 Optics, Pneumatics, and Hydrostatics) in the room below the 
 University Library. The number of names was 26. The 
 Lectures terminated on Mar. 22nd. 
 
 "On Feb. 25th I received from Mr Pond information on 
 the emoluments at Greenwich Observatory. I drew up a 
 second manifesto, and on Feb. 26th I wrote and signed a 
 formal copy for the Plumian electors. On Feb. 27th I met 
 them at Caius Lodge (the Master, Dr Davy, being Vice- 
 Chancellor). I read my Paper, which was approved, and 
 their sanction was given in the form of a request to the Vice- 
 Chancellor to permit the paper to be printed and circulated. 
 My paper, with this request at the head, was immediately 
 printed, and a copy was sent to every resident M.A. (more 
 than 200 went out in one day). The statement and composi- 
 tion of the paper were generally approved, but the University 
 had never before been taken by storm in such a manner, and 
 there was some commotion about it. I believe that very few 
 persons would have taken the same step. Mr Sheepshanks 
 wrote to me on Mar. 7th, intimating that it was desperate. 
 I had no doubt of success. Whewell told me that some 
 people accused me of bad faith, in omitting allusion to the 
 100 a year received as Member of the Board of Longitude, 
 and to the profits of Lectures. I wrote him a note, telling 
 him that I had most certain information of the intention to 
 
FROM B.A. DEGREE TO PLUMIAN PROFESSORSHIP. 8 1 
 
 dissolve the Board of Longitude (which was done in less than 
 six months), and that by two years' Lectures I had gained 
 4$ (the expenses being 200, receipts 245). This letter 
 was sent to the complaining people, and no more was said. 
 By the activity of Sheepshanks and the kindness of Dr Davy 
 the business gradually grew into shape, and on Mar. 2ist a 
 Grace passed the Senate for appointing a Syndicate to con- 
 sider of augmentation. Sheepshanks was one of the Syndi- 
 cate, and was understood to represent, in some measure, my 
 interests. The progress of the Syndicate however was by no 
 means a straightforward one. Members of the Senate soon 
 began to remark that before giving anything they ought to 
 know the amount of the University revenue, and another 
 Syndicate was then appointed to enquire and report upon it. 
 It was more than a year before my Syndicate could make 
 their recommendation : however, in fact, I lost nothing by 
 that delay, as I was rising in the estimation of the University. 
 "The Observatory house was furnished, partly from Wood- 
 house's sale, and partly from new furniture. My mother and 
 sister came to live with me there. On Mar. I5th 1828 I 
 began the Observatory Journal ; on Mar. 2/th I slept at 
 the Observatory for the first time, and on Apr. i5th I came 
 to reside there permanently, and gave up my college rooms." 
 
 A. B. 
 
CHAPTER IV. 
 
 AT CAMBRIDGE OBSERVATORY. FROM HIS TAKING 
 CHARGE OF THE CAMBRIDGE OBSERVATORY TO HIS 
 
 RESIDENCE AT GREENWICH OBSERVATORY AS AS- 
 
 TRONOMER ROYAL. 
 
 FROM MARCH ISTH 1828 TO JAN. IST 1836. 
 
 1828 
 
 " I attended a meeting of the Board of Longitude on Apr. 
 3rd. And again on June 4th ; this was the last meeting : 
 Sheepshanks had previously given me private information of 
 the certainty of its dissolution. On Apr. 4th I visited Mr 
 Herschel at Slough, where one evening I saw Saturn with 
 his 2O-foot telescope, the best view of it that I have ever 
 had. In June I attended the Greenwich Observatory Visi- 
 tation. Before my election (as Plumian Professor) there are 
 various schemes on my quires for computation of transit 
 corrections, &c. After Apr. I5th there are corrections for 
 deficient wires, inequality of pivots, &c. And I began a 
 book of proposed regulations for observations. In this are 
 plans for groups of stars for R.A. (the Transit Instrument 
 being the only one finished): order of preference of classes of 
 observations: no reductions to be made after dinner, or on 
 Sunday : no loose papers : observations to be stopped if 
 reductions are two months in arrear: stars selected for 
 parallax. The reduction of transits begins on Apr. I5th. 
 On May I5th Mr Pond sent me some moon-transits to aid in 
 determining my longitude. Dr Young, in a letter to me of 
 
AT CAMBRIDGE OBSERVATORY. 83 
 
 May /th, enquires whether I will accept a free admission to 
 the Royal Society, which I declined. On May pth I was 
 elected to the Astronomical Society. Towards the end of 
 the year I observed Encke's Comet: and determined the 
 latitude of the Observatory with Sheepshanks's repeating 
 circle. On my papers I find a sketch of an Article on the 
 Figure of the Earth for the Encyclopaedia Metropolitana. 
 
 "As early as Feb. 23rd I had been in correspondence 
 with T. Jones, the instrument-maker, about pendulums for a 
 repetition of the Dolcoath Experiments. Invitations had 
 been received, and everything was arranged with Whewell. 
 Sheepshanks, my brother, and Mr Jackson of Ipswich (Caius 
 Coll.) were to go. and we were subsequently joined by 
 Sedgwick, and Lodge (Magdalene Coll.). On July 3rd Sheep- 
 shanks and I started by Salisbury, taking Sherborne on our 
 way to look at the church, which had alarmed the people by 
 signs of a crack, and arrived at Camborne on July 8th. On 
 the I4th we set up the pendulums, and at once commenced 
 observations, our plan being, to have no intermission in the 
 pendulum observations, so that as soon as the arc became too 
 small a fresh series was started. On July 2Qth we raised the 
 instruments, and Sheepshanks, who managed much of the 
 upper operations, both astronomical and of pendulums, 
 mounted the pendulums together in his observatory. We 
 went on with our calculations, and on August 8th, on return- 
 ing from a visit to John Williams at Barncoose, we heard that 
 there was a * run ' in Dolcoath, that is a sinking of the whole 
 mass of rock where it had been set free by the mine excava- 
 tions: probably only a few inches, but enough to break the 
 rock much and to stop the pumps. On Aug. loth the calcu- 
 lations of our observations shewed that there was something 
 wrong, and on the I3th I perceived an anomaly in the 
 form of the knife edge of one pendulum, and of its agate 
 planes, and suggested cautions for repeating the observations. 
 We determined at once to repeat them : and as the water 
 was rising in the mine there was no time to be lost. We 
 
 62 
 
84 GEORGE BIDDELL AIRY. 
 
 again sent the instruments down, and made observations on 
 the 1 6th, 1 7th and i8th. On the igth I sent the instruments 
 up, for the water was near our station, and Sedgwick, Whewell, 
 and I went on a geological expedition to the Lizard. On 
 our return we met Sheepshanks and the others, and found 
 the results of the last observations unsatisfactory. The 
 results of comparing the pendulums were discordant, and the 
 knife edge of the faulty pendulum had very sensibly altered. 
 We now gave up observations, with the feeling that our 
 time had been totally lost, mainly through the fault of the 
 maker of the pendulum (T. Jones). On the 28th we made 
 an expedition to Penzance and other places, and arrived at 
 Cambridge on the i/th of September. 
 
 " In the course of the work at Dolcoath we made various 
 expeditions as opportunity offered. Thus we walked to 
 Carn Brea and witnessed the wrestling, the common game 
 of the country. On another occasion Sedgwick, Whewell, 
 and I had a capital geological expedition to Trewavas Head 
 to examine granite veins. We visited at Pendarves and 
 Trevince, and made the expedition to the Lizard already 
 referred to, and saw many of the sights in the neighbourhood. 
 After visiting Penzance on the conclusion of our work we 
 saw Cape Cornwall (where Whewell overturned me in a gig), 
 and returned homewards by way of Truro, Plymouth (where 
 we saw the watering-place and breakwater: also the Dock- 
 yard, and descended in one of the working diving-bells), 
 Exeter, Salisbury, and Portsmouth. In returning from 
 Camborne in 1826 I lost the principal of our papers. It 
 was an odd thing that, in going through Exeter on our way 
 to Camborne in 1828, I found them complete at Exeter, 
 identified to the custodian by the dropping out of a letter 
 with my address. 
 
 " On my return to Cambridge I was immediately im- 
 mersed in the work of the Observatory. The only instru- 
 ment then mounted at the Observatory was the Transit. I 
 had no Assistant whatever. A Mr Galbraith of Edinburgh 
 
AT CAMBRIDGE OBSERVATORY. 85 
 
 had questioned something in one of my Papers about the 
 Figure of the Earth. I drew up a rather formal answer to it: 
 Whewell saw my draft and drew up a much more pithy one, 
 which I adopted and sent to the Philosophical Magazine. 
 For comparing our clocks at the upper and lower stations of 
 Dolcoath we had borrowed from the Royal Observatory, 
 Greenwich, six good pocket chronometers : they were still in 
 the care of Mr Sheepshanks. I arranged with him that they 
 should be sent backwards and forwards a few times for 
 determining the longitude of Cambridge Observatory. This 
 was done on Oct. 2ist, 22nd, 23rd: the result was 23 S *54, and 
 this has been used to the present time (1853). It evinced 
 an error in the Trigonometrical Survey, the origin of which 
 was found, I think, afterwards (Dr Pearson in a letter of Dec. 
 1 7th spoke of the mistake of a may-pole for a signal-staff). 
 I drew up a Paper on this, and gave it to the Cambridge 
 Philosophical Society on Nov. 24th. (My only academical 
 Paper this year.) I had several letters from Dr Young, 
 partly supplying me with calculations that I wanted, partly 
 on reform or extension of the Nautical Almanac (which Dr 
 Young resisted as much as possible). He considered me 
 very unfairly treated in the dissolution of the Board of 
 Longitude : Professor Lax wished me to join in some effort 
 for its restoration, but I declined. 
 
 " As my reduction of observations was kept quite close, I 
 now began to think of printing. In regard to the form I 
 determined to adopt a plan totally different from that of any 
 other observations which I had seen. The results were to be 
 the important things : I was desirous of suppressing the 
 separate wires of transits. But upon consulting Herschel 
 and other persons they would not agree to it, and I assented 
 to keeping them. I applied to the Press Syndicate to print 
 the work, and on Nov. loth at the request of T. Musgrave 
 (afterwards Archbishop of York) I sent a specimen of my 
 MS.: on Nov. nth they granted 250 copies, and the printing 
 soon commenced." 
 
86 GEORGE BIDDELL AIRY. 
 
 1829 
 
 " During a winter holiday at Playford I wrote out some 
 investigations about the 'orbits 0T comets, and on Jan. 23rd 
 1829 I returned to Cambridge. The Smith's Prize Exami- 
 nation soon followed, in which I set a Paper of questions as 
 usual. On Feb. i8th I made notes on Liesganig's geodetic 
 work at the British Museum. 
 
 " I was naturally anxious now about the settlement of my 
 salary and of the Observatory establishment. I do not 
 know when the Syndicate made their Report, but it must 
 have been in the last term of 1828. It recommended that 
 the salary should be annually made up (by Grace) to 500 : 
 that an Assistant should be appointed with the assent of the 
 Vice-Chancellor- and dismissable by the Plumian Professor: 
 and that a Visiting Syndicate should be appointed, partly 
 official and partly of persons to be named every year by 
 Grace. The Grace for adopting this Report was to be 
 offered to the Senate on Feb. 27th. The passing of the 
 Grace was exposed to two considerable perils. First, I 
 found out (just in time) that a Senior Fellow of Trinity 
 (G. A. Browne) was determined to oppose the whole, on ac- 
 count of the insignificant clause regarding dismissal of Assist- 
 ants, which he regarded as tyrannical. I at once undertook 
 that that clause should be rejected. Secondly, by the absurd 
 constitution of the ' Caput ' at Cambridge, a single M. A. had 
 the power of stopping any business whatever, and an M.A. 
 actually came to the Senate House with the intention of 
 throwing out all the Graces on various business that day 
 presented to the Senate. Luckily he mistook the hour, and 
 came at 1 1 instead of 10, and found that all were dispatched. 
 The important parts of the Grace passed without any opposi- 
 tion : but I mustered some friends who negatived that part 
 which had alarmed G. A. Browne, and it was corrected to his 
 satisfaction by a new Grace on Mar. i8th. I was now almost 
 
AT CAMBRIDGE OBSERVATORY. 87 
 
 set at rest on one of the great objects of my life: but not 
 quite. I did not regard, and I determined not to regard, the 
 addition to my salary as absolutely certain until a payment 
 had been actually made to me : and I carefully abstained, 
 for the present, from taking any steps based upon it. I found 
 for Assistant at the Observatory an old Lieutenant of the 
 Royal Navy, Mr Baldrey, who came on Mar. 16. 
 
 " On May 4th I began lectures : there were 32 names. 
 The Lectures were improving, especially in the optical part. 
 I do not find note of the day of termination. I do not know 
 the actual day of publication of my first small volume of 
 Cambridge Observations, 1828, and of circulation. The date 
 of the preface is Apr. 2/th 1829. I have letters of approval 
 of it from Davies Gilbert, Rigaud, and Lax. The system 
 which I endeavoured to introduce into printed astronomical 
 observations was partially introduced into this volume, and 
 was steadily improved in subsequent volumes. I think that I 
 am justified, by letters and other remarks, in believing that 
 this introduction of an orderly system of exhibition, not 
 merely of observations but of the steps for bringing them to 
 a practical result quite a novelty in astronomical publica- 
 tions had a markedly good effect on European astronomy 
 in general. In Feb. and March I have letters from Young 
 about the Nautical Almanac : he was unwilling to make any 
 great change, but glad to receive any small assistance. South, 
 who had been keeping up a series of attacks on Young, wrote 
 to me to enquire how I stood in engagements of assistance to 
 Young : I replied that I should assist Young whenever he 
 asked me, and that I disapproved of South's course. The 
 date of the first visitation of the (Cambridge) Observatory 
 must have been near May nth: I invited South and Baily 
 to my house ; South and I were very near quarrelling about 
 the treatment of Young. In a few days after Dr Young 
 died : I applied to Lord Melville for the superintendence of 
 the Nautical Almanac: Mr Croker replied that it devolved 
 legally upon the Astronomer Royal, and on May 3<Dth Pond 
 
88 GEORGE BIDDELL AIRY. 
 
 wrote to ask my assistance when I could give any. On June 
 6th I was invited to the Greenwich Visitation, to which I 
 believe I went on the loth. 
 
 " I had long desired to see Switzerland, and I wished now 
 to see some of the Continental /Observatories. I was there- 
 fore glad to arrange with Mr Lodge, of Magdalene College 
 (perhaps 10 years senior to myself), to make a little tour. 
 Capt. W. H. Smyth and others gave me introductions. I met 
 Lodge in London, and we started for Calais on July 2;th 
 1829. We visited a number of towns in Belgium (at Brussels 
 I saw the beginning of the Observatory with Quetelet), and 
 passed by Cologne, Frankfort, Fribourg, and Basle to Zurich. 
 Thus far we had travelled by diligence or posting : we now 
 procured a guide, and travelled generally on foot. From the 
 1 3th to the 3 ist August we travelled diligently through the 
 well-known mountainous parts of Switzerland and arrived at 
 Geneva on the 3ist August. Here I saw M. Gautier, M. 
 Gambard, and the beginning of the Observatory. Mr Lodge 
 was now compelled to return to Cambridge, and I proceeded 
 alone by Chambery to Turin, where I made the acquaintance 
 of M. Plana and saw the Observatory. I then made a tour 
 through north Italy, looking over the Observatories at Milan, 
 Padua, Bologna, and Florence. At Leghorn I took a passage 
 for Marseille in a xebeque, but after sailing for three days 
 the weather proved very unfavourable, and I landed at Spezia 
 and proceeded by Genoa and the Cornici Road to Marseille. 
 At Marseille I saw M. Gambart and the Observatory, and 
 passed by Avignon, Lyons, and Nevers to Orleans, where I 
 visited my old host M. Legarde. Thence by Paris, Beauvais, 
 and Calais to London and Cambridge, where I arrived on 
 the 30th October. I had started with more than 140 and 
 returned with 2s. 6d. The expedition was in many ways 
 invaluable to me. 
 
 " On my return I found various letters from scientific 
 men : some approving of my method for the mass of the 
 Moon : some approving highly of my printed observations, 
 
AT CAMBRIDGE OBSERVATORY. 89 
 
 especially D. Gilbert, who informed me that they had pro- 
 duced good effect (I believe at Greenwich), and Herschel. 
 On Nov. 1 3th I gave the Royal Astronomical Society a 
 Paper about deducing the mass of the Moon from observa- 
 tions of Venus : on Nov. i6th a Paper to the Cambridge 
 Philosophical Society on a correction to the length of a ball- 
 pendulum : and on Dec. I4th a Paper on certain conditions 
 under which perpetual motion is possible. The engravings 
 for my Figure of the Earth in the Encyclopaedia Metropoli- 
 tana were dispatched at the end of the year. Some of the 
 Paper (perhaps much) was written after my return from the 
 Continent. I began, but never finished, a Paper on the form 
 of the Earth supposed to be projecting at middle latitudes. 
 In this I refer to the printed Paper which Nicollet gave me at 
 Paris. I believe that the investigations for my Paper in the 
 Encyclopaedia Metropolitana led me to think the supposition 
 unnecessary. On Nov. 6th I was elected member of the 
 Geological Society. 
 
 "On Nov. 1 6th 1829 notice was given of a Grace to 
 authorize payment to me of 157. gs. id., in conformity with 
 the regulations adopted on Feb. 27th, and on Nov. i8th the 
 Grace passed the Senate. On Nov. I9th the Vice-Chancellor 
 wrote me a note enclosing the cheque. On Nov. 23rd (prac- 
 tically the first day on which I could go) I went to London 
 and travelled to Edensor, where I arrived on the 26th. Here 
 I found Richarda Smith, proposed to her, and was accepted. 
 I stayed there a few days, and returned to Cambridge." 
 
 1830 
 
 "On Jan. 25th 1830 the Smith's Prize Paper was prepared. 
 I was (with my Assistant, Mr Baldrey) vigorously working 
 the Transit Instrument and its reductions, and gradually 
 forming a course of proceeding which has had a good effect 
 on European Astronomy. And I was preparing for my 
 marriage. 
 
GEORGE BIDDELL AIRY. 
 
 "On Mar. nth I started with my sister to London, and 
 arrived at Edensor on the afternoon of the I4th. On the 
 1 7th I started alone for Manchester and Liverpool. Through 
 Mr Mason, a cotton-spinner at Calver, near Edensor, I had 
 become acquainted with Mr Johft Kennedy of Manchester, 
 and I had since 1824 been acquainted with Dr Traill of 
 Liverpool. Amongst other things, I saw the works of the 
 Manchester and Liverpool Railway, then advancing and 
 exciting great interest, and saw George Stephenson and his 
 son. On Mar. 24th I was married to Richarda Smith by her 
 father in Edensor. We stopped at Edensor till Apr. 1st, and 
 then started in chaises by way of Newark and Kettering 
 (where we were in danger of being stopped by the snow), and 
 arrived at Cambridge on Apr. 3rd. 
 
 " I was now busy in preparing for lectures, especially the 
 part of the optical lectures which related to the theory of 
 interferences and polarization. I think it was now that my 
 wife drew some of my lecture pictures, exhibiting interference 
 phenomena. My lectures began on Apr. 26th and finished 
 on May 24th. The number of names was 50- They were 
 considered an excellent course of lectures. 
 
 " May Qth is the date of my Preface to the 1829 Observa- 
 tions : all was then printed. Apparently I did not go to the 
 Visitation of the Greenwich Observatory this year. I was at 
 this time pressing Tulley, the optician, about an object-glass 
 for the Mural Circle. A new edition of my ' Tracts ' was 
 wanted, and I prepared to add a Tract on the Undulatory 
 Theory of Light in its utmost extent. The Syndicate of the 
 University Press intimated through Dr Turton that they 
 could not assist me (regarding the book as a second edition). 
 On July loth I have some negociation about it with Deighton 
 the bookseller. On May i8th I have a note from Whewell 
 about a number of crystals of plagiedral quartz, in which he 
 was to observe the crystalline indication, and I the optical 
 phenomena. The Report of the Syndicate for visiting the 
 Observatory is dated June i8th : it is highly laudatory. The 
 
AT CAMBRIDGE OBSERVATORY. 91 
 
 Proctor (Barnard of King's College) requested me to name 
 the Moderator for the next B.A. Examination : I named Mr 
 Challis. 
 
 " On June I4th my wife and I went, in company with Pro- 
 fessor and Mrs Henslow, to London and Oxford ; at Oxford 
 we were received in Christchurch College by Dr and Mrs 
 Buckland. My wife and I then went to Bedford to visit 
 Capt. and Mrs Smyth, and returned to Cambridge on the 
 23rd. On July 5th we went on a visit to my mother and 
 uncle at Playford. While there I took a drive with my uncle 
 into some parts near the valley of the Gipping, in which I 
 thought that the extent of the chalk was inadequately 
 exhibited on Greenough's map, and communicated my re- 
 marks to Buckland. 
 
 " I find letters from Dr Robinson and Col. Colby about 
 determining longitudes of certain observatories by fire signals : 
 I proposed chronometers as preferable. Also from Herschel, 
 approving of my second volume of observations : and from 
 F. Baily, disclaiming the origination of the attack on the old 
 Nautical Almanac (with which I suppose I had reproached 
 him). On July 3Oth I received a summons from South to a 
 committee for improving the Nautical Almanac ; and subse- 
 quently a letter from Baily about Schumacher's taking 
 offence at a passage of mine in the Cambridge Observations, 
 on the comparative merits of Ephemerides, which I after- : 
 wards explained to his satisfaction. 
 
 " On Aug. 24th my wife and I started for Edensor, and 
 after a short stay there proceeded by Manchester to Cumber- 
 land, where we made many excursions. We returned by 
 Edensor, and reached Cambridge on Oct. 6th, bringing my 
 wife's sister Susanna on a visit. My mother had determined, 
 as soon as my intention of marriage was known to her, to 
 quit the house, although always (even to her death) enter- 
 taining the most friendly feelings and fondness for my wife. 
 It was also judged best by us all that my sister should not 
 reside with us as a settled inhabitant of the house. They 
 
92 GEORGE BIDDELL AIRY. 
 
 fixed themselves therefore at Playford in the farm-house of 
 the Luck's Farm, then in the occupation of my uncle Arthur 
 Biddell. On Oct. 2ist I have a letter from my sister saying 
 that they were comfortably settled there. 
 
 " In this month of October (principally, I believe) I made 
 some capital Experiments on Quartz, which were treated 
 mathematically in a Paper communicated in the next year to 
 the Cambridge Philosophical Society. In some of these my 
 wife assisted me, and also drew pictures. On Nov. I5th the 
 Grace for paying me 198. i$s. %d. to make my income up to 
 500 passed the Senate. I made three journeys to London 
 to attend committees, one a committee on the Nautical 
 Almanac, and one a Royal Society Committee about two 
 southern observatories. On Dec. 3ist I have a letter from 
 Maclear (medical practitioner and astronomer at Biggies- 
 wade) about occultations. In this December I had a quartz 
 object-glass by Cauchaix mounted by Dollond, and presented 
 it to the Observatory. In this December occurred the alarm 
 from agrarian fires. There was a very large fire at Coton, 
 about a mile from the Observatory. This created the most 
 extraordinary panic that I ever saw. I do not think it is 
 possible, without having witnessed it, to conceive the state of 
 men's minds. The gownsmen were all armed with bludgeons, 
 and put under a rude discipline for a few days." 
 
 1831 
 
 " On Jan. 4th I went with my wife, first to Miss Sheep- 
 shanks in London, at 30, Woburn Place, and next to the 
 house of my wife's old friend, the Rev. John Courtney, at 
 Sanderstead, near Croydon. I came to London on one day 
 to attend a meeting of the new Board of Visitors of the 
 Greenwich Observatory. Formerly the Board of Visitors 
 consisted of the Council of the Royal Society with persons 
 invited by them (in which capacity I had often attended). 
 But a reforming party, of which South, Babbage, Baily and 
 
AT CAMBRIDGE OBSERVATORY. 93 
 
 Beaufort were prominent members, had induced the Admi- 
 ralty to constitute a new Board, of which the Plumian Pro- 
 fessor was a member. Mr Pond, the Astronomer Royal, was 
 in a rather feeble state, and South seemed determined to 
 bear him down : Sheepshanks and I did our best to support 
 him. (I have various letters from Sheepshanks to this pur- 
 pose.) On Jan. 22nd we returned to Cambridge, and I set 
 an Examination Paper for Smith's Prizes as usual. On Jan. 
 30th I have a letter from Herschel about improving the 
 arrangement of Pond's Observations. I believe that much of 
 this zeal arose from the example of the Cambridge Observa- 
 tions. 
 
 "On Feb. 2ist my Paper ' On the nature of the light in 
 the two rays of Quartz' was communicated to the Philoso- 
 phical Society : a capital piece of deductive optics. On Mar. 
 2nd I went to London, I suppose to attend the Board of 
 Visitors (which met frequently, for the proposed reform of 
 Pond's Observations, &c.). As I returned on the outside of 
 the coach there occurred to me a very remarkable deduction 
 from my ideas about the rays of Quartz, which I soon tried 
 with success, and it is printed as an Appendix to the Paper 
 above mentioned. On Mar. 6th my son George Richard was 
 born." 
 
 Miscellaneous matters in the first half of this year are as 
 follows : 
 
 " Faraday sends me a piece of glass for Amici (he had 
 sent me a piece before). On Apr. 9th I dispatched the Pre- 
 face of my 1830 Observations: this implies that all was 
 printed. On Apr. i8th I began my Lectures and finished on 
 May 24th. There were 49 names. A very good series of 
 lectures. I think it was immediately after this, at the Visita- 
 tion of the Cambridge Observatory, that F. Baily and Lieut. 
 Stratford were present, and that Sheepshanks went to Thar- 
 field on the Royston Downs to fire powder signals to be seen 
 at Biggies wade (by Maclear) and at Bedford (by Capt. Smyth) 
 as well as by us at Cambridge. On May I4th I received 
 
94 GEORGE BIDDELL AIRY. 
 
 100 for my article on the Figure of the Earth from Baldwin 
 the publisher of the Encyclopaedia Metropolitana. I attended 
 the Greenwich Visitation on June 3rd. On June 3Oth the 
 Observatory Syndicate made their report : satisfactory. 
 
 "On July 6th 1831 I started with my wife and infant son 
 for Edensor, and went on alone to Liverpool. I left for 
 Dublin on the day on which the loss of the ' Rothsay Castle ' 
 was telegraphed, and had a bad voyage, which made me ill 
 during my whole absence. After a little stay in Dublin I 
 went to Armagh to visit Dr Robinson, and thence to Cole- 
 raine and the Giant's Causeway, returning by Belfast and 
 Dublin to Edensor. We returned to Cambridge on Sept. Qth. 
 
 " Up to this time the Observatory was furnished with 
 only one large instrument, namely the lo-foot Transit. On 
 Feb. 24th of this year I had received from Thomas Jones 
 (62, Charing Cross) a sketch of the stone pier for mounting 
 the Equatoreal which he was commissioned to make: and the 
 pier was prepared in the spring or summer. On Sept. 2Oth 
 part of the instrument was sent to the Observatory ; other 
 parts followed, and Jones himself came to mount it. On 
 Sept. 1 6th I received Simms's assurance that he was hasten- 
 ing the Mural Circle. In this autumn I seriously took up 
 the recalculation of my Long Inequality of Venus and the 
 Earth, and worked through it independently ; thus correcting 
 two errors. On Nov. roth I went to Slough, to put my 
 Paper in the hands of Mr Herschel for communication to the 
 Royal Society. The Paper was read on Nov. 24th. This 
 was the year of the first Meeting of the British Association at 
 York. The next year's meeting was to be at Oxford, and on 
 Oct. 1 7th I received from the Rev. W. Vernon Harcourt an 
 invitation to supply a Report on Astronomy, which I under- 
 took : it employed me much of the winter, and the succeeding 
 spring and summer. The second edition of my Tracts was 
 ready in October. It contained, besides what was in the first 
 edition, the Planetary Theory, and the Undulatory Theory of 
 Light. The Profit was 80. On Nov. I4th I presented to 
 
AT CAMBRIDGE OBSERVATORY. 95 
 
 the Cambridge Philosophical Society a Paper ' On a remark- 
 able modification of Newton's Rings ' : a pretty good Paper. 
 In November the Copley Medal was awarded to me by the 
 Royal Society for my advances in Optics. Amongst miscel- 
 laneous matters I was engaged in correspondence with Col. 
 Colby and Capt. Portlock about the Irish Triangulation and 
 its calculation. Also with the Admiralty on the form of 
 publication of the Greenwich and Cape Observations." 
 
 1832 
 
 " In January my Examination Paper for Smith's Prizes 
 was prepared as usual. Two matters (in addition to the 
 daily routine of Observatory work) occupied me at the begin- 
 ning of this year. One was the translation of Encke's Paper 
 in successive numbers of the Astronomische Nachrichten 
 concerning Encke's Comet ; the University Press printed this 
 gratuitously, and I distributed copies, partly by the aid of 
 Capt. Beaufort. The other was the Report on Astronomy 
 for the British Association, which required much labour. 
 My reading for it was principally in the University Library 
 (possibly some in London), but I borrowed some books from 
 F. Baily, and I wrote to Capt. Beaufort about the possible 
 repetition of Lacaille's Meridian Arc at the Cape of Good 
 Hope. The Report appears to have been finished on May 
 2nd. At this time the Reform Bill was under discussion, 
 and one letter written by me (probably at Sheepshanks's 
 request) addressed I think to Mr Drummond, Lord Althorp's 
 secretary, was read in the House of Commons. 
 
 " Optics were not neglected. I have some correspondence 
 with Brewster and Faraday. On Mar. 5th I gave the Cam- 
 bridge Philosophical Society a Paper ' On a new Analyzer/ 
 and on Mar. ipth. one 'On Newton's Rings between two sub- 
 stances of different refractive powers,' both Papers satisfac- 
 tory to myself. On the death of Mr F. Fallows, astronomer 
 at the Cape of Good Hope Observatory, the Admiralty 
 
96 GEORGE BIDDELL AIRY. 
 
 appointed Mr Henderson, an Edinburgh lawyer, who had 
 done some little things in astronomical calculation. On Jan. 
 loth I discussed with him observations to be made, and drew 
 up his Official Instructions whigh were sent on Jan. i6th. 
 On Feb. i6th Sir James South Writes that Encke's Comet is 
 seen : also that with his 1 2-inch achromatic, purchased at 
 Paris, and which he was preparing to mount equatoreally, he 
 had seen the disk of Aldebaran apparently bisected by the 
 Moon's limb. Capt. Beaufort and D. Gilbert write in March 
 about instructions to Dunlop, the astronomer at Paramatta. 
 I sent a draft to Capt. Beaufort on Apr. 27th. 
 
 " The Preface to my 1831 Observations is dated Mar. 2Oth. 
 The distribution of the book would be a few weeks later. 
 On May 7th I began my Lectures : 5 1 names : I finished on 
 May 29th. The mounting of the Equatoreal was finished 
 some time before the Syndicate Visitation at the end of May, 
 but Jones's charge appeared to be exorbitant : I believe it 
 was paid at last, but it was considered unfair. On June 2nd 
 I went to London : I presume to the Greenwich Visitation. 
 I went to Oxford to the meeting of the British Association 
 (lodging I think with Prof. Rigaud at the Observatory) on 
 June 1 6th, and read part of my Report on Astronomy in the 
 Theatre. 
 
 "On June 26th I started with my wife for the Highlands of 
 Scotland. After a short stay at Edensor, we went by Carlisle 
 to Glasgow, and through the Lake District to Inverness. 
 Thence by Auchnanault to Balmacarra, where we were 
 received by Mr Lillingstone. After an expedition in Skye, 
 we returned to Balmacarra, and passed on to Invermoriston, 
 where we were received by Grant of Glenmoriston. We then 
 went to Fort William and Oban, and crossed over to Mull, 
 where we were received by Maclean of Loch Buy. We 
 returned to Oban and on to Edinburgh, where we made a 
 short stay. Then to Melrose, where we were received by 
 Sir D. Brewster, and by Edensor to Cambridge, where we 
 arrived on Sept. I7th. 
 
AT CAMBRIDGE OBSERVATORY. 97 
 
 " I received (at Edinburgh I believe) a letter from Arago, 
 writing for the plans of our observing-room shutters. Mr 
 Vernon Harcourt wrote deprecating the tone of my Report 
 on Astronomy as related to English Astronomers, but I 
 refused to alter a word. Sheepshanks wrote in September in 
 great anxiety about the Cambridge Circle, for which he 
 thought the pier ought to be raised : I would have no such 
 thing, and arranged it much more conveniently by means of 
 a pit. On Oct. gth Simms says that he will come with the 
 circle immediately, and Jones on Sept. 29th says that he will 
 make some alteration in the equatoreal : thus there was at 
 last a prospect of furnishing the Observatory properly. On 
 Oct. 9th, I have Encke's thanks for the translation of the 
 Comet Paper. One of the desiderata which I had pointed 
 out in my Report on Astronomy was the determination of 
 the mass of Jupiter by elongations of the 4th satellite : and 
 as the Equatoreal of the Cambridge Observatory was on the 
 point of coming into use, I determined to employ it for this 
 purpose. It was necessary for the reduction of the observa- 
 tions that I should prepare Tables of the motion of Jupiter's 
 4th Satellite in a form applicable to computations of dif- 
 ferences of right-ascension. The date of my Tables is Oct. 
 3rd, 1832. In October the Observatory Syndicate made their 
 Report : quite satisfactory. 
 
 " On Oct. 2Oth Sheepshanks wrote asking my assistance in 
 the Penny Cyclopaedia : I did afterwards write * Gravitation ' 
 and ' Greenwich.' Capt. Beaufort wrote in November to ask 
 my opinion on the Preface to an edition of Groombridge's 
 Catalogue which had been prepared by H. Taylor: Sheep- 
 shanks also wrote; he had objected to it. This was the 
 beginning of an affair which afterwards gave me great 
 labour. Vernon Harcourt writes, much offended at some 
 terms which I had used in reference to an office in the British 
 Association. 
 
 " The Equatoreal mounting which Troughton and Simms 
 had been preparing for Sir James South's large telescope 
 A. B. 7 
 
98 GEORGE BIDDELL AIRY. 
 
 had not entirely succeeded. I have various letters at this 
 time from Sheepshanks and Simms, relating to the disposi- 
 tion which Sir James South shewed to resist every claim till 
 compelled by law to pay it. A .general election of Members 
 of Parliament was now coming on : Mr Lubbock was candi- 
 date for the University. On Nov. 27th I had a letter from 
 Sedgwick requesting me to write a letter in the newspapers 
 in favour of Lubbock; which I did. On Dec. 7th I have 
 notice of the County voting at Newmarket on Dec. i8th and 
 1 9th : I walked there to vote for Townley ; he lost the 
 election by two or three votes in several thousands. 
 
 " The Mural Circle was now nearly ready in all respects, 
 and it was known that another Assistant would be required. 
 Mr Richardson (one of the Assistants of Greenwich Ob- 
 servatory) and Mr Simms recommended to me Mr Glaisher, 
 who was soon after appointed, and subsequently became an 
 Assistant at Greenwich. On Dec. 24th I have a letter from 
 Bessel (the first I believe). I think that I had written to him 
 about a general reduction of the Greenwich Planetary Ob- 
 servations, using his Tabulae Regiomontanae as basis, and 
 that this was his reply approving of it. 
 
 1833 
 
 "On Jan. 4th 1833 my daughter Elizabeth was born. I 
 prepared an examination paper for Smith's Prizes as usual. 
 On Jan. 5th I received notice from Simms that he had 
 received payment (1050) for the Mural Circle from the 
 Vice-Chancellor. About this time the Circle was completely 
 made serviceable, and I (with Mr Glaisher as Assistant) im- 
 mediately began its use. A puzzling apparent defect in the 
 circle (exhibiting itself by the discordance of zenith points 
 obtained by reflection observations on opposite sides of the 
 zenith) shewed itself very early. On Feb. 4th I have letters 
 about it from Sheepshanks and Simms. On Jan. I7th I 
 received notice from F. Baily that the Astronomical Society 
 had awarded me their Medal for my long inequality of 
 
AT CAMBRIDGE OBSERVATORY. 99 
 
 Venus and the Earth : on Feb. 7th I went to London, I 
 suppose to receive the Medal. I also inspected Sir J. South's 
 telescope, then becoming a matter of litigation, and visited 
 Mr Herschel at Slough: on Feb. I2th I wrote to Sir J. 
 South about the support of the instrument, hoping to remove 
 one of the difficulties in the litigation ; but it produced no 
 effect. Herschel wrote to me, from Poisson, that Ponte- 
 coulant had verified my Long Inequality. 
 
 "Mar. I2th is the date of the Preface to my 1832 volume 
 of Observations: it was of course distributed a few weeks 
 later. In my Report on Astronomy I had indicated the 
 Mass of Jupiter as a subject requiring fresh investigation. 
 During the last winter I had well employed the Equatoreal 
 in observing elongations in R.A. of the 4th Satellite. To 
 make these available it was necessary to work up the theory 
 carefully, in which I discovered some remarkable errors of 
 Laplace. Some of these, for verification, I submitted to Mr 
 Lubbock, who entirely agreed with me. The date of my 
 first calculations of the Mass of Jupiter is Mar. 1st : and 
 shortly after that I gave an oral account of them to the 
 Cambridge Philosophical Society. The date of my Paper for 
 the Astronomical Society is April I2th. The result of my 
 investigations (which was subsequently confirmed by Bessel) 
 entirely removed the difficulty among Astronomers ; and the 
 mass which I obtained has ever since been received as the 
 true one. 
 
 "On Apr. 9th my wife's two sisters, Elizabeth and 
 Georgiana Smith, came to stay with me. On Apr. 22nd I 
 began lectures, and finished on May 2ist: there were 54 
 names. During the course of the lectures I communicated a 
 Paper to the Philosophical Society ' On the calculation of 
 Newton's experiments on Diffraction.' I went to London on 
 the Visitation of the Greenwich Observatory : the dinner had 
 been much restricted, but was now made more open. It had 
 been arranged that the meeting of the British Association 
 was to be held this year at Cambridge. I invited Sir David 
 
 72 
 
100 GEORGE BIDDELL AIRY. 
 
 Brewster and Mr Herschel to lodge at the Observatory. 
 The meeting lasted from June 24th to 3Oth. We gave one 
 dinner, but had a breakfast party every day. I did not enter 
 much into the scientific business of the meeting, except that 
 I brought before the Committee the expediency of reducing 
 the Greenwich Planetary Observations from 1750. They 
 agreed to represent it to the Government, and a deputation 
 was appointed (I among them) who were received by Lord 
 Althorp on July 25th. On Aug. 3rd Herschel announced to 
 me that 500 was granted. 
 
 " On Aug. 7th I started with my wife for Edensor. At 
 Leicester we met Sedgwick and Whewell : my wife went on 
 to Edensor, and I joined Sedgwick and Whewell in a 
 geological expedition to Mount Sorrel and various parts of 
 Charnwood Forest. We were received by Mr Allsop of 
 Woodlands, who proved an estimable acquaintance. This 
 lasted four or five days, and we then went on to Edensor. 
 On Aug. 1 5th Herschel wrote to me, communicating an offer 
 of the Duke of Northumberland to present to the Cambridge 
 Observatory an object-glass of about 12 inches aperture by 
 Cauchaix. I wrote therefore to the Duke, accepting gene- 
 rally. The Duke wrote to me from Buxton on Aug. 23rd 
 (his letter, such was the wretched arrangement of postage, 
 reaching Bakewell and Edensor on the 25th) and on the 26th 
 I drove before breakfast to Buxton and had an interview 
 with him. On Sept. ist the Duke wrote, authorizing me to 
 mount the telescope entirely, and he subsequently approved 
 of Cauchaix's terms : there was much correspondence, but 
 on Dec. 28th I instructed Cauchaix how to send the tele- 
 scope. On our return we paid a visit to Dr Davy, Master 
 of Caius College, at Heacham, and reached Cambridge on 
 Oct. 8th. 
 
 " Groombridge's Catalogue, of which the editing was for- 
 mally entrusted to Mr Henry Taylor (son of Taylor the first- 
 assistant of the Greenwich Observatory), had been in some 
 measure referred to Sheepshanks: and he, in investigating 
 
AT CAMBRIDGE OBSERVATORY. 
 
 the work, found reason for thinking the whole discreditable. 
 About May he first wrote to me on his rising quarrel with H. 
 Taylor, but on Sept. /th he found things coming to a crisis, 
 and denounced the whole. Capt. Beaufort the Hydro- 
 grapher (in whose office this matter rested) begged me with 
 Baily to decide upon it. We did not at first quite agree upon 
 the terms of investigation &c., but after a time all was settled, 
 and on Oct. 4th the Admiralty formally applied, and I for- 
 mally 7 accepted. Little or nothing had been done by Mr 
 Baily and myself, when my work was interrupted by illness. 
 
 " Sheepshanks had thought that something might be done 
 to advance the interests of myself or the Observatory by the 
 favour of Lord Brougham (then Lord Chancellor), and had 
 urged me to write an article in the Penny Cyclopaedia, in 
 which Lord Brougham took great interest. I chose the 
 subject ' Gravitation,' and as I think wrote a good deal of it 
 in this Autumn : when it was interrupted by my illness. 
 
 "On Dec. 9th 1833, having at first intended to attend 
 the meeting of the Philosophical Society and then having 
 changed my mind, I was engaged in the evening on the 
 formulae for effects of small errors on the computation of 
 the Solar Eclipse of 1833. A dizziness in my head came 
 on. I left off work, became worse, and went to bed, and in 
 the night was in high fever with a fierce attack of scarlet 
 fever. My wife was also attacked but very slightly. The 
 first day of quitting my bedroom was Dec. 3ist. Some- 
 where about the time of my illness my wife's sister, Susanna 
 Smith, who was much reduced in the summer, died of con- 
 sumption. 
 
 " Miscellaneous notes in 1833 are as follows: Henderson 
 (at the Cape) could not endure it much longer, and on 
 Oct. 1 4th Stratford writes that Maclear had just sailed to 
 take his place : Henderson is candidate for the Edinburgh 
 Observatory. Stratford writes on Dec. 2nd that the Madras 
 observations have come to England, the first whose arrange- 
 ment imitates mine. On Nov. 3rd Herschel, just going to 
 
GEORGE BIDDELL AIRY. 
 
 the Cape, entrusted to me the revisal of some proof sheets, if 
 necessary : however it was never needed. In November I 
 sat for my portrait to a painter named Purdon (I think): he 
 came to the house and made a good likeness. A pencil 
 portrait was taken for a print-seller (Mason) in Cambridge : 
 it was begun before my illness and finished after it. I 
 applied through Sheepshanks for a copy of Maskelyne's 
 Observations, to be used in the Reduction of the Planetary 
 Observations : and on Dec. 24th (from my bedroom) I ap- 
 plied through Prof. Rigaud to the Delegates of the Clarendon 
 Press for a copy of Bradley's Observations for the same. 
 The latter request was refused. In October I applied to the 
 Syndics of the University Press for printed forms for these 
 Reductions : the Syndics agreed to grant me 12,000 copies. 
 
 1834 
 
 "On Jan. nth 1834 I went with my wife to London for 
 the recruiting of my strength. We stayed at the house of 
 our friend Miss Sheepshanks, and returned on Feb. I3th. 
 I drew up a Paper of Questions for Smith's Prizes, but left 
 the whole trouble of examination and adjudication to Pro- 
 fessor Miller, who at my request acted for me. While I was 
 in London I began to look at the papers relating to Groom- 
 bridge's Catalogue : and I believe that it was while in London 
 that I agreed with Mr Baily on a Report condemnatory of 
 H. Taylor's edition, and sent the Report to the Admiralty. 
 The Admiralty asked for further advice, and on Feb. 28th I 
 replied, undertaking to put the Catalogue in order. On Mar. 
 1 7th Capt. Beaufort sent me all the papers. Some time how- 
 ever elapsed before I could proceed with it. 
 
 " There was in this spring a furious discussion about the 
 admission of Dissenters into the University : I took the 
 Liberal side. On Apr. 3Oth there was a letter of mine in 
 the Cambridge newspaper. On Apr. I4th I began lectures, 
 and finished on May 2Oth : there were 87 names. My 'Gravi- 
 
AT CAMBRIDGE OBSERVATORY. IO3 
 
 tation ' was either finished or so nearly finished that on Jan. 
 24th I had some conversation with Knight the publisher 
 about printing it. It was printed in the spring, and on Apr. 
 27th Sheepshanks sent a copy of it to Lord Brougham. I 
 received from Knight 83. i?s. id. for this Paper. On May 
 loth I went to London, I believe to attend one of the Soirees 
 which the Duke of Sussex gave as President of the Royal 
 Society. The Duke invited me to breakfast privately with 
 him the next morning. He then spoke to me, on the part of 
 the Government, about my taking the office of Astronomer 
 Royal. On May ipth I wrote him a semi-official letter, to 
 which reference was made in subsequent correspondence on 
 that subject. 
 
 "On May I2th my son Arthur was born. In June the 
 Observatory Syndicate made a satisfied Report On June 
 7th I went to the Greenwich Visitation, and again on June 
 1 4th I went to London, I believe for the purpose of trying 
 the mounting of South's telescope, as it had been strengthened 
 by Mr Simms by Sheepshanks's suggestions. I was sub- 
 sequently in correspondence with Sheepshanks on the subject 
 of the Arbitration on South's telescope, and my giving evi- 
 dence on it. On July 29th, as I was shortly going away, I 
 wrote him a Report on the Telescope, to be used in case of 
 my absence. The award, which was given in December, was 
 entirely in favour of Simms. On July 23rd I went out, I 
 think to my brother's marriage at Ixworth in Suffolk. On 
 Aug. ist I started for Edensor and Cumberland, with my 
 wife, sister, and three children : Georgiana Smith joined us 
 at Edensor. We went by Otley, Harrogate, Ripon, and 
 Stanmoor to Keswick, from whence we made many excur- 
 sions. On Aug. nth I went with Whewell to the clouds on 
 Skiddaw, to try hygrometers. Mr Baily called on his way to 
 the British Association at Edinburgh. On Sept. loth we 
 transferred our quarters to Ambleside, and after various 
 excursions we returned to Edensor by Skipton and Bolton. 
 On Sept. ipth I went to Doncaster and Finningley Park to 
 
104 GEORGE BIDDELL AIRY. 
 
 see Mr Beaumont's Observatory. On Sept. 25th we posted 
 in one day from Edensor to Cambridge. 
 
 " On Aug. 25th Mr Spring Rice (Lord Monteagle) wrote 
 to me to enquire whether I would; accept the office of Astro- 
 nomer Royal if it were vacant. 'I replied (from Keswick) on 
 Aug. 3Oth, expressing my general willingness, stipulating for 
 my freedom of vote, &c., and referring to my letter to the 
 Duke of Sussex. On Oct. 8th Lord Auckland, First Lord of 
 the Admiralty, wrote : and on Oct. loth I provisionally ac- 
 cepted the office. On Oct. 3<Dth I wrote to ask for leave to give 
 a course of lectures at Cambridge in case that my successor 
 at Cambridge should find difficulty in doing it in the first 
 year : and to this Lord Auckland assented on Oct. 3ist. All 
 this arrangement was for a time upset by the change of 
 Ministry which shortly followed. 
 
 "Amongst miscellaneous matters, in March I had some 
 correspondence with the Duke of Northumberland about the 
 Cauchaix Telescope. In August I had to announce to him 
 that the flint-lens had been a little shattered in Cauchaix's 
 shop and required regrinding : finally on Dec. i/th I an- 
 nounced its arrival at Cambridge. In the Planetary Reduc- 
 tions. I find that I employed one computer (Glaisher) for 34 
 weeks. In November the Lalande Medal was awarded to me 
 by the French Institut, and Mr Pentland conveyed it to me 
 in December. On March I4th I gave the Cambridge Philo- 
 sophical Society a Paper, ' Continuation of researches into 
 the value of Jupiter's Mass.' On Apr. I4th, 'On the Lati- 
 tude of Cambridge Observatory.' On June I3th, 'On the 
 position of the Ecliptic,' and ' On the Solar Eclipse of 1833,' 
 to the Royal Astronomical Society. On Nov. 24th, 'On 
 Computing the Diffraction of an Object Glass,' to the Cam- 
 bridge Society. And on Dec. 3rd, ' On the Calculation of 
 Perturbations,' to the Nautical Almanac : this Paper was 
 written at Keswick between Aug. 22nd and 29th. I also 
 furnished Mr Sheepshanks with investigations regarding the 
 form of the pivots of the Cape Circle. 
 
AT CAMBRIDGE OBSERVATORY. 1 05 
 
 1835 
 
 "On Jan. Qth 1835 I was elected correspondent of the 
 French Academy; and on Jan. 26th Mr Pentland sent me 
 12. 6s., the balance of the proceeds of the Lalande Medal 
 Fund. I prepared my Paper for Smith's Prizes, and joined 
 in the Examination as usual. 
 
 "There had been a very sudden change of Administra- 
 tion, and Sir R. Peel was now Prime Minister as First Lord 
 of the Treasury, and Lord Lyndhurst was Lord Chancellor. 
 On Jan. I9th I wrote to Lord Lyndhurst, asking him for a 
 Suffolk living for my brother William, which he declined to 
 give, though he remembered my application some years later. 
 Whether my application led to the favour which I shortly 
 received from the Government, I do not know. But, in 
 dining with the Duke of Sussex in the last year, I had been 
 introduced to Sir R. Peel, and he had conversed with me a 
 long time, and appeared to have heard favourably of me. 
 On Feb. i;th he wrote to me an autograph letter offering a 
 pension of 300 per annum, with no terms of any kind, and 
 allowing it to be settled if I should think fit on my wife. 
 I wrote on Feb. i8th accepting it for my wife. In a few 
 days the matter went through the formal steps, and Mr 
 Whewell and Mr Sheepshanks were nominated trustees for 
 my wife. The subject came before Parliament, by the Whig 
 Party vindicating their own propriety in having offered me 
 the office of Astronomer Royal in the preceding year ; and 
 Spring Rice's letter then written to me was published in the 
 Times, &c." 
 
 The correspondence relating to the pension above-men- 
 tioned is given below, and appears to be of interest, both as 
 conveying in very felicitous terms the opinion of a very 
 eminent statesman on the general subject of such pensions, 
 and as a most convincing proof of the lofty position in Science 
 which the subject of this Memoir had then attained. 
 
106 GEORGE BIDDELL AIRY. 
 
 WHITEHALL GARDENS, 
 Feb. 17 1835. 
 
 SIR, 
 
 You probably are aware that in a Resolution voted by the 
 House of Commons in the last Session of Parliament, an opinion 
 was expressed, that Pensions on the Civil List, ought not thereafter 
 to be granted by the Crown excepting for the satisfaction of certain 
 public claims, among which those resting on Scientific or Literary 
 Eminence were especially mentioned. 
 
 I trust that no such Resolution would have been necessary to 
 induce me as Minister of the Crown fully to recognize the justice of 
 such claims, but I refer to the Resolution, as removing every im- 
 pediment to a Communication of the nature of that which I am 
 about to make to you. 
 
 In acting upon the Principle of the Resolution in so far as the 
 Claims of Science are concerned, my first address is made to you, 
 and made directly, and without previous communication with any 
 other person, because it is dictated exclusively by public considera- 
 tions, and because there can be no advantage in or any motive for 
 indirect communication. 
 
 I consider you to have the first claim on the Royal Favour which 
 Eminence in those high Pursuits to which your life is devoted, can 
 give, and I fear that the Emoluments attached to your appointment 
 in the University of Cambridge are hardly sufficient to relieve you 
 from anxiety as to the Future on account of those in whose welfare 
 you are deeply interested. 
 
 The state of the Civil List would enable me to advise the King 
 to grant a pension of three hundred pounds per annum, and if the 
 offer be acceptable to you the Pension shall be granted either to 
 Mrs Airy or yourself as you may prefer. 
 
 I beg you distinctly to understand that your acquiescence in this 
 Proposal, will impose upon you no obligation personal or political in 
 the slightest degree. I make it solely upon public grounds, and I ask 
 you, by the acceptance of it, to permit the King to give some slight 
 encouragement to Science, by proving to those who may be disposed 
 to follow your bright Example, that Devotion to the highest Branches 
 of Mathematical and Astronomical Knowledge shall not necessarily 
 
AT CAMBRIDGE OBSERVATORY. 
 
 involve them in constant solicitude as to the future condition of 
 those, for whom the application of the same Talents to more lucra- 
 tive Pursuits would have ensured an ample Provision. 
 
 I have the honor to be, Sir, 
 
 With true Respect and Esteem, 
 Your faithful Servant, 
 
 ROBERT PEEL. 
 
 Mr Professor Airy, 
 
 &>, 6<T., 
 
 Cambridge. 
 
 OBSERVATORY, CAMBRIDGE, 
 1835, Feb. 1 8. 
 
 SIR, 
 
 I have the honor to acknowledge your letter of the 
 acquainting me with your intention of advising the King to grant a 
 pension of ^300 per annum from the Civil List to me or Mrs Airy. 
 
 I trust you will believe that I am sensible of the flattering terms 
 in which this offer is made, and deeply grateful for the considerate 
 manner in which the principal arrangement is left to my choice, as 
 well as for the freedom from engagement in which your offer leaves 
 me. I beg to state that I most willingly accept the offer. I should 
 prefer that the pension be settled on Mrs Airy (by which I under- 
 stand that in case of her surviving me the pension would be con- 
 tinued to her during her life, or in the contrary event would cease 
 with her life). 
 
 I wish that I may have the good fortune to prove to the world 
 that I do not accept this offer without an implied engagement on 
 my part. I beg leave again to thank you for your attention, and to 
 assure you that the form in which it is conveyed makes it doubly 
 acceptable. 
 
 With sincere respect I have the honor to be, Sir, 
 Your very faithful Servant, 
 
 G. B. AIRY. 
 
 The Right Hon. Sir Robert Peel, Bart., 
 First Lord of the Treasury, 6<r., &>c. 
 
108 GEORGE BIDDELL AIRY. 
 
 WHITEHALL, 
 
 Feb. igth 1835. 
 SIR, 
 
 I will give immediate directions for the preparation of 
 the Warrant settling the Pension on^Mrs Airy the effect of which 
 will be, as you suppose, to grant the' Pension to her for her life. I 
 assure you I never gave an official order, which was accompanied 
 with more satisfaction to myself than this. 
 
 I have the honor to be, Sir. 
 
 Your faithful Servant, 
 
 ROBERT PEEL. 
 Mr Professor Airy, 
 
 6<r., 6<r., 
 
 Cambridge. 
 
 "On March i8th 1835 I started (meeting Sheepshanks at 
 Kingstown) for Ireland. We visited Dublin Observatory, 
 and then went direct to Markree near Sligo, to see Mr 
 Cooper's telescope (our principal object). We passed on our 
 return by Enniskillen and BallyjamesdurT, where my former 
 pupil P. Morton was living, and returned on Apr. 3rd. On 
 Apr. 2Oth I was elected to the Royal Society, Edinburgh. 
 Apr. 22nd my wife wrote me from Edensor that her sister 
 Florence was very ill : she died shortly after. On May 4th I 
 began lectures and finished on May 2Qth : there were 58 
 names. My former pupil Guest asks my interest for the 
 Recordership of Birmingham. In June was circulated the 
 Syndicate Report on the Observatory. The date of the 
 Preface to the 1834 Observations is June i6th. 
 
 " The Ministry had been again changed in the spring, and 
 the Whigs were again in power. On June nth Lord Auck- 
 land, who was again First Lord of the Admiralty (as last 
 year), again wrote to me to offer me the office of Astronomer 
 Royal, or to request my suggestions on the filling up of the 
 office. On June i5th I wrote my first reply, and on June 
 I /th wrote to accept it. On June i8th Lord Auckland 
 acknowledges, and on June 22nd the King approved. Lord 
 
AT CAMBRIDGE OBSERVATORY, log 
 
 Auckland appointed to see me on Friday, June 23rd, but I 
 was unwell. I had various correspondence with Lord Auck- 
 land, principally about buildings, and had an appointment 
 with him for August I3th. As Lord Auckland was just 
 quitting office, to go to India, I was introduced to Mr Charles 
 Wood, the Secretary of the Admiralty, with whom principally 
 the subsequent business was transacted. At this meeting 
 Lord Auckland and Mr Wood expressed their feeling, that 
 the Observatory had fallen into such a state of disrepute that 
 the whole establishment ought to be cleared out. I repre- 
 sented that I could make it efficient with a good First Assis- 
 tant ; and the other Assistants were kept. But the establish- 
 ment was in a queer state. The Royal Warrant under the 
 Sign Manual was sent on August nth. It was understood 
 that my occupation of office would commence on October 1st, 
 but repairs and alterations of buildings would make it impos- 
 sible for me to reside at Greenwich before the end of the 
 year. On Oct. ist I went to the Observatory, and entered 
 formally upon the office (though not residing for some time). 
 Oct. /th is the date of my Official Instructions. 
 
 " I had made it a condition of accepting the office that 
 the then First Assistant should be removed, and accordingly 
 I had the charge of seeking another. I determined to have a 
 man who had taken a respectable Cambridge degree. I 
 made enquiry first of Mr Bowstead (brother to the bishop) 
 and Mr Steventon : at length, consulting Mr Hopkins (a 
 well-known private tutor at Cambridge), he recommended to 
 me Mr Robert Main, of Queens' College, with whom I corre- 
 sponded in the month (principally) of August, and whom on 
 August 30th I nominated to the Admiralty. On Oct. 2ist 
 F. W. Simms, one of the Assistants (who apparently had 
 hoped for the office of First Assistant, for which he was 
 quite incompetent) resigned ; and on Dec. 4th I appointed 
 in his place Mr James Glaisher, who had been at Cambridge 
 from the beginning of 1833, an< ^ on Dec. loth the Admiralty 
 approved. 
 
HO GEORGE BIDDELL AIRY. 
 
 " During this quarter of a year I was residing at Cam- 
 bridge Observatory, visiting Greenwich once a week (at least 
 for some time), the immediate superintendence of the Obser- 
 vatory being placed with Mr Main. I was however engaged 
 in reforming the system of the Greenwich Observatory, and 
 prepared and printed 30 skeleton forms for reductions of 
 observations and other business. On Dec. I4th I resigned 
 my Professorship to the Vice-Chancellor. But I continued 
 the reduction of the observations, so that not a single figure 
 was left to my successor : the last observations were those of 
 Halley's Comet. The Preface to my 1835 Cambridge Obser- 
 vations is dated Aug. 22nd, 1836. 
 
 "In regard to the Northumberland Telescope, I had 
 for some time been speculating on plans of mounting and 
 enclosing the instrument, and had corresponded with Simms, 
 A. Biddell, Cubitt, and others on the subject. On Apr. 24th 
 Tulley the younger was endeavouring to adjust the object- 
 glass. On May 3ist I plainly asked the Duke of Northum- 
 berland whether he would defray the expense of the mount- 
 ing and building. On June 4th he assented, and money was 
 placed at a banker's to my order. I then proceeded in 
 earnest: in the autumn the building was erected, and the 
 dome was covered before the depth of winter. I continued 
 in 1836 to superintend the mounting of the instrument. 
 
 "In regard to the Planetary Reductions: to July nth 
 J. Glaisher had been employed 27 weeks, and from July I ith to 
 Jan. i6th, 1836, 25 weeks. Mr Spring Rice, when Chancellor 
 of the Exchequer, had promised money, but no official minute 
 had been made, and no money had been granted. On Aug. 
 2 ist I applied to Mr Baring (Secretary of the Treasury). 
 After another letter he answered on Oct. I5th that he found 
 no official minute. After writing to Vernon Harcourt and to 
 Spring Rice, the matter was arranged : my outlay was re- 
 funded, and another sum granted. In regard to Groom- 
 bridge's Observations, I find that on Dec. i6th certain 
 trial reductions had been made under my direction by 
 
AT CAMBRIDGE OBSERVATORY. Ill 
 
 J. Glaisher. I had attempted some optical experiments in 
 the summer, especially on the polarization of sky-light ; but 
 had been too busy with the Observatory to continue them. 
 
 " In August my wife was in a critical state of health. In 
 December I received information regarding merchant ships' 
 chronometers, for which I had applied to Mr Charles Parker 
 of Liverpool. On Dec. 8th Mr Spring Rice and Lord John 
 Russell offered me knighthood, but I declined it. On July 
 23rd I went into Suffolk with my wife's sisters Elizabeth and 
 Georgiana, and returned on August 3rd : this was all the 
 holiday that I got in this year. On the I4th of August I 
 saw Mr Taylor, the Admiralty Civil Architect in London, 
 and the extension of buildings at Greenwich Observatory 
 was arranged. I made various journeys to Greenwich, and 
 on Dec. i;th, having sent off our furniture, we all quitted the 
 Cambridge Observatory, and stayed for some days at the 
 house of Miss Sheepshanks. 
 
 " Thus ended a busy and anxious year." 
 
 With reference to the offer of knighthood above-men- 
 tioned, Airy's reply is characteristic, and the short corre- 
 spondence relating to it is therefore inserted. The offer 
 itself is an additional proof of the high estimation in which 
 he stood at this time. 
 
 DOWNING STREET, 
 
 Dec. 8tti 1835. 
 MY DEAR SIR, 
 
 I have been in communication with my colleague Lord 
 John Russell which has made me feel rather anxious to have the 
 pleasure of seeing you, but on second thoughts it has occurred to me 
 that the subject of my communication would render it more satisfac- 
 tory to you to receive a letter than to pay a visit. 
 
 In testimony of the respect which is felt for your character and 
 acquirements, there would be every disposition to recommend you to 
 His Majesty to receive the distinction of Knighthood. I am quite 
 aware that to you individually this may be a matter of small concern, 
 
112 GEORGE BIDDELL AIRY. 
 
 but to the scientific world in general it will not be indifferent, and to 
 foreign countries it will mark the consideration felt for you personally 
 as well as for the position which you occupy among your learned 
 contemporaries. 
 
 From a knowledge of the respecfand esteem which I feel for you 
 Lord John Russell has wished that the communication should be 
 made through me rather than through any person who had not the 
 pleasure of your acquaintance. K 
 
 Pray let me hear from you and believe me my dear Sir, with 
 compliments to Mrs Airy, 
 
 Very truly yours, 
 
 T. SPRING RICE. 
 
 P.S. It may be right to add that when a title of honor is con- 
 ferred on grounds like those which apply to your case, no fees or 
 charges of any kind would be payable. 
 
 OBSERVATORY, CAMBRIDGE, 
 1835, Dec. loth. 
 
 MY DEAR SIR, 
 
 I beg to acknowledge your letter of the 8th, which I have 
 received at this place, conveying to me an intimation of the wish of 
 His Majesty's Ministers to recommend me to the King for the honor 
 of Knighthood. 
 
 I beg to assure you that I am most sensible to the liberality 
 which I have experienced from the Government in other as well as 
 in pecuniary matters, and that I am very highly gratified by the con- 
 sideration (undeserved by me, I fear) which they have displayed in 
 the present instance. And if I now request permission to decline 
 the honor offered to me, I trust I may make it fully understood that 
 it is not because I value it lightly or because I am not anxious to 
 receive honors from such a source. 
 
 The unalterable custom of this country has attached a certain 
 degree of light consideration to titles of honor which are not sup- 
 ported by considerable fortune ; or at least, it calls for the display of 
 such an establishment as may not be conveniently supported by 
 even a comfortable income. The provision attached to my official 
 situation, and the liberality of the King towards one of the members 
 of my family, have placed me in a position of great comfort. These 
 circumstances however have bound me to consider myself as the 
 devoted servant of the country, and to debar myself from efforts to 
 
AT CAMBRIDGE OBSERVATORY. 113 
 
 increase my fortune which might otherwise have been open to me. 
 I do not look forward therefore to any material increase of income, 
 and that which I enjoy at present is hardly sufficient, in my opinion, 
 to support respectably the honor which you and Lord John Russell 
 have proposed to confer upon me. For this reason only I beg leave 
 most respectfully to decline the honor of Knighthood at the present 
 time. 
 
 I have only to add that my services will always be at the com- 
 mand of the Government in any scientific subject in which I can be 
 of the smallest use. 
 
 I am, my dear Sir, 
 
 Your very faithful Servant, 
 
 G. B. AIRY. 
 The Right Honorable T. Spring Rice. 
 
 "In brief revision of the years from 1827 to 1835 I may 
 confine myself to the two principal subjects my Professorial 
 Lectures, and my Conduct of the Cambridge Observatory. 
 
 "The Lectures as begun in 1827 included ordinary 
 Mechanics, ordinary Hydrostatics and Pneumatics (I think 
 that I did not touch, or touched very lightly, on the subjects 
 connected with the Hydraulic Ram), and ordinary Optics 
 (with a very few words on Polarization and Depolarization). 
 In 1828 the two first were generally improved, and for the 
 third (Optics) I introduced a few words on Circular Polariza- 
 tion. I believe that it was in 1829 that I made an addition 
 to the Syllabus with a small engraving, shewing the inter- 
 ference of light in the best practical experiment (that of the 
 flat prism) ; and I went thoroughly into the main points of 
 the Undulatory Theory, interference, diffraction, &c. In 1830 
 I believe I went (in addition to what is mentioned above) into 
 Polarization and Depolarization of all kinds. My best lec- 
 ture diagrams were drawn and painted by my wife. The 
 Lectures were universally pronounced to be valuable. The 
 subjects underwent no material change in 1831, 2, 3, 4, 5; 
 and I believe it was a matter of sincere regret to many 
 
 A. B. 8 
 
114 GEORGE BIDDELL AIRY. 
 
 persons that my removal to Greenwich terminated the series. 
 Each lecture nominally occupied an hour. But I always 
 encouraged students to stop and talk with me; and this 
 supplement was usually considered a valuable part of the 
 lecture. Practically the lecture 7 , on most days, occupied two 
 hours. I enjoyed the Lectures much : yet I felt that the 
 labour (in addition to other work) made an impression on my 
 strength, and I became at length desirous of terminating 
 them. 
 
 " The Observatory, when I took charge of it, had only one 
 instrument the Transit-Instrument. The principles how- 
 ever which I laid down for my own direction were adapted 
 to the expected complete equipment. Planets (totally neg- 
 lected at Greenwich) were to be observed. Observations 
 were to be reduced completely, and the reductions were to be 
 exhibited in an orderly way : this was a novelty in Astro- 
 nomy. I considered it so important that I actually proposed 
 to omit in my publication the original observations, but was 
 dissuaded by Herschel and others. I sometimes suspended 
 observations for a short time, in order to obtain leisure for 
 the reductions. I had at first no intention of correcting the 
 places of the fundamental stars as settled at Greenwich. But 
 I found myself compelled to do so, because they were not 
 sufficiently accurate ; and then I took the course of observing 
 and reducing as an independent observer, without reference 
 to any other observatory. I introduced the principle of not 
 correcting instrumental errors, but measuring them and apply- 
 ing numerical corrections. I determined my longitude by 
 chronometers, and my latitude by a repeating circle borrowed 
 from Mr Sheepshanks, which I used so well that the result 
 was only half a second in error. The form of my reductions 
 in the published volume for 1828 is rather irregular, but the 
 matter is good : it soon attracted attention. In 1829 the 
 process was much the same : I had an assistant, Mr Baldrey. 
 In 1830 still the same, with the additions: that I formally 
 gave the corrections of relative right-ascension of fundamental 
 
AT CAMBRIDGE OBSERVATORY. 1 15 
 
 stars (without alteration of equinox, which I had not the 
 means of obtaining) to be used in the year 1831 ; and that I 
 reduced completely the observed occultations (with a small 
 error, subsequently corrected). In 1831 the system of correc- 
 tion of broken transits was improved : the errors of assumed 
 R. A. of Fundamental Stars were exhibited : Mean Solar 
 Time was obtained from Sidereal Time by time of Transit 
 of T (computed by myself) : the method of computing occul- 
 tations was improved. In 1832 the small Equatoreal was 
 erected, and was soon employed in observations of the elon- 
 gation of the 4th Satellite of Jupiter for determining the 
 mass of Jupiter. The Mural Circle was erected at the end of 
 the year, but not used. The calculation of R. A. of Funda- 
 mental Stars was made homogeneously with the others : 
 separate results of all were included in ledgers : a star-cata- 
 logue was formed: all as to the present time (1871). With 
 the Equatoreal the difference of N. P. D. of Mars and stars 
 was observed. 
 
 "With the beginning of 1833 the Mural Circle was estab- 
 lished at work, a second assistant (Mr Glaisher) was appointed, 
 and the Observatory might be considered complete. I made 
 experiments on the graduations of the Circle. I detected 
 and was annoyed by the R D. I determined the latitude. 
 I exhibited the separate results for N. P. D. of stars in ledger, 
 and their means in Catalogue. I investigated from my obser- 
 vations the place of equinox and the obliquity of the ecliptic. 
 I made another series of observations of Jupiter's 4th Satel- 
 lite, for the mass of Jupiter. I observed the solar eclipse 
 with the Equatoreal, by a method then first introduced, 
 which I have since used several times at Cambridge and 
 Greenwich with excellent effect. The Moon and the Planets 
 were usually observed till near two in the morning. Correc- 
 tion for defective illumination applied when necessary. The 
 volume is very complete, the only deficiency being in the 
 observation of Moon and Planets through the severe morning 
 hours. In 1834 the only novelties are examination of the 
 
 82 
 
Il6 GEORGE BIDDELL AIRY. 
 
 graduations of the declination circle of the Equatoreal (exces- 
 sively bad): observations of a spot on Jupiter for rotation, 
 and of Mars and stars. In 1835 (including January 1836) 
 there is a more complete examination of the Equatoreal 
 graduations : parallax and refraction for Equatoreal observa- 
 tions : a spot on Jupiter : a series of observations on Jupiter's 
 4th Satellite for the mass of Jupiter: Mars, and stars: Hal- 
 ley's Comet (the best series of observations which could be 
 made in the season) : and a short series of meteorological 
 observations, on a plan suggested by Sir John Herschel then 
 at the Cape of Good Hope. 
 
 " I cannot tell precisely in which year I introduced the 
 following useful custom. Towards the end of each year I 
 procured a pocket-book for the following year with a space 
 for every day, and carefully examining all the sources of 
 elements of observations, and determining the observations 
 to be made every day, I inserted them in the pocket-book. 
 This system gave wonderful steadiness to the plan of obser- 
 vations for the next year. The system has been maintained 
 in great perfection at the Observatory of Greenwich. (The 
 first of these pocket-books which Prof. Adams has found is 
 that for 1833.) Printed skeleton forms were introduced for 
 all calculations from 1828. In the Greenwich Observatory 
 Library there is a collection, I believe complete, of printed 
 papers commencing with my manifesto, and containing all 
 Syndicate Reports except for 1833 (when perhaps there was 
 none). It seems from these that my first written Report on 
 Observations, &c., was on May 3Oth, 1834. The first Syndi- 
 cate Report is on May 25th, 1829." 
 
 A few remarks on Airy's private life and friends during 
 his residence at Cambridge Observatory may be here appro- 
 priately inserted. 
 
 Amid the laborious occupations recorded in the foregoing 
 pages, his social life and surroundings appear to have been 
 
AT CAMBRIDGE OBSERVATORY. 1 I? 
 
 most pleasant and congenial. At that period there were in 
 residence in Cambridge, and particularly at Trinity, a large 
 number of very brilliant men. Airy was essentially a Cam- 
 bridge man. He had come up poor and friendless : he had 
 gained friends and fame at the University, and his whole 
 work had been done there. From the frequent references in 
 after times both by him and his wife to their life at Cam- 
 bridge, it is clear that they had a very pleasant recollection 
 of it, and that the social gatherings there were remarkably 
 attractive. He has himself recorded that with Whewell and 
 Sedgwick, and his accomplished sisters-in-law, who were 
 frequently on long visits at the Observatory, they formed 
 pretty nearly one family. 
 
 His friendship with Whewell was very close. Although 
 Whewell was at times hasty, and rough-mannered, and even 
 extremely rude, yet he was generous and large-minded, and 
 thoroughly upright 1 . In power of mind, in pursuits, and 
 interests, Airy had more in common with Whewell than with 
 any other of his friends. It was with Whewell that he under- 
 took the experiments at Dolcoath : it was to Whewell that 
 he first communicated the result of his remarkable investiga- 
 tion of the Long Inequality of Venus and the Earth; and 
 some of his Optical researches were conducted jointly with 
 Whewell. Whewell took his degree in 1816, seven years 
 before Airy, and his reputation, both for mathematical and 
 all-round knowledge, was extremely and deservedly great, 
 but he was always most generous in his recognition of Airy's 
 powers. Thus in a letter of Mar. i6th, 1823 (Life of William 
 Whewell by Mrs Stair Douglas), he says, "Airy is certainly a 
 most extraordinary man, and deserves everything that can 
 
 1 The following passage occurs in a letter from Airy to his wife, dated 1845, 
 Sept. lyth: 
 
 " I am sorry that * * * * speaks in such terms of the ' Grand Master,' as she 
 used to be so proud of him : it is only those who have well gone through the 
 ordeal of quarrels with him and almost insults from him, like Sheepshanks and 
 me, that thoroughly appreciate the good that is in him : I am sure he will never 
 want a good word from me." 
 
Il8 GEORGE BIDDELL AIRY. 
 
 be said of him" ; and again in the autumn of 1826 he writes 
 to his aunt, "You mentioned a difficulty which had occurred 
 to you in one of your late letters ; how Airy should be made 
 Professor while I was here, who," being your nephew, must of 
 course, on that account, deserve it better than he could. 
 Now it is a thing which you will think odd, but it is never- 
 theless true, that Airy is a better mathematician than your 
 nephew, and has moreover been much more employed of late 
 
 in such studies Seriously speaking, Airy is by very 
 
 much the best person they could have chosen for the situa- 
 tion, and few things have given me so much pleasure as his 
 election." How much Whewell depended upon his friends 
 at the Observatory may be gathered from a letter which he 
 wrote to his sister on Dec. 2ist, 1833. " We have lately been 
 in alarm here on the subject of illness. Two very near friends 
 of mine, Prof, and Mrs Airy, have had the scarlet fever at 
 the same time ; she more slightly, he very severely. They 
 are now, I am thankful to say, doing well and recovering 
 rapidly. You will recollect that I was staying with them at 
 her father's in Derbyshire in the summer. They are, I think, 
 two of the most admirable and delightful persons that the 
 world contains." And again on Dec. 2Oth, 1835, he wrote to 
 his sister Ann, " My friends I may almost say my dearest 
 friends Professor Airy and his family have left Cambridge, 
 he being appointed Astronomer Royal at Greenwich to me 
 an irreparable loss ; but I shall probably go and see how 
 they look in their new abode." Their close intercourse was 
 naturally interrupted by Airy's removal to Greenwich, but 
 their friendly feelings and mutual respect continued without 
 material break till Whewell's death. There was frequent 
 correspondence between them, especially on matters con- 
 nected with the conduct and teaching of the University, in 
 which they both took a keen interest, and a warm welcome 
 at Trinity Lodge always awaited Mr and Mrs Airy when 
 they visited Cambridge. In a letter written to Mrs Stair 
 Douglas on Feb. nth, 1882, enclosing some of Whewell's 
 
AT CAMBRIDGE OBSERVATORY. 119 
 
 letters, there occurs the following passage : " After the decease 
 of Mrs Whewell, Whewell wrote to my wife a mournful letter, 
 telling her of his melancholy state, and asking her to visit 
 him at the Lodge for a few days. And she did go, and did 
 the honours of the house for several days. You will gather 
 from this the relation in which the families stood." Whewell 
 died on Mar. 6th, 1866, from the effects of a fall from his 
 horse, and the following extract is from a letter written by 
 Airy to Whewell's niece, Mrs Sumner Gibson, on hearing of 
 the death of his old friend : 
 
 " The Master was, I believe, my oldest surviving friend 
 (beyond my own family), and, after an acquaintance of 46 
 years, I must have been one of his oldest friends. We have 
 during that time been connected privately and officially : we 
 travelled together and experimented together : and as oppor- 
 tunity served (but I need not say in very different degrees) 
 we both laboured for our College and University. A terrible 
 blank is left on my mind." 
 
 Sedgwick was probably 1 5 years older than Airy : he 
 took his degree in 1808. But the astonishing buoyancy of 
 spirits and bonhomie of Sedgwick fitted him for all ages 
 alike. He was undoubtedly the most popular man in Cam- 
 bridge in modern times. His ability, his brightness and wit, 
 his fearless honesty and uprightness, his plain-speaking and 
 good humour, rendered him a universal favourite. His close 
 alliance with Airy was much more social than scientific. It 
 is true that they made some geological excursions together, 
 but, at any rate with Airy, it was far more by way of recrea- 
 tion than of serious study, and Sedgwick's science was entirely 
 geological. Their friendship continued till Sedgwick's death, 
 though it was once or twice imperilled by Sedgwick's impul- 
 sive and hasty nature. 
 
 Peacock took his degree in 1813 (Herschel's year), and 
 was therefore probably 10 years older than Airy. He was 
 the earliest and staunchest friend of Airy in his undergraduate 
 years, encouraged him in every possible way, lent him books, 
 
I2O GEORGE BIDDELL AIRY. 
 
 assisted him in his studies, helped him with wise advice on 
 many occasions, and took the greatest interest in his success. 
 He was a good and advanced mathematician, and with a 
 great deal of shrewdness and Common-sense he united a 
 singular kindness and gentleness of manner. It is therefore 
 not to be wondered at that he was regarded by Airy with the 
 greatest esteem and affection, and though they were after- 
 wards separated, by Peacock becoming Dean of Ely and 
 Airy Astronomer Royal, yet their warm friendship was never 
 broken. The following letter, written by Airy to Mrs Pea- 
 cock on receiving the news of the death of the Dean, well 
 expresses his feelings towards his old friend : 
 
 TRINITY LODGE, CAMBRIDGE, 
 1858, Dec. 4. 
 
 MY DEAR MADAM, 
 
 I have desired for some time to express to you my 
 sympathies on occasion of the sad bereavement which has come 
 upon me perhaps as strongly as upon any one not connected by 
 family ties with my late friend. But I can scarcely give you an idea 
 how every disposable moment of my time has been occupied. I am 
 now called to Cambridge on business, and I seize the first free time 
 to write to you. 
 
 My late friend was the first person whom I knew in College (I 
 had an introduction to him when I went up as freshman). From 
 the first, he desired me to consider the introduction not as entitling 
 me to a mere formal recognition from him, but as authorizing me at 
 all times to call on him for any assistance which I might require. 
 And this was fully carried out : I referred to him in every difficulty : 
 I had the entire command of his rooms and library (a very important 
 aid in following the new course of mathematics which he had been 
 so instrumental in introducing into the University) in his occasional 
 absences : and in all respects I looked to him as to a parent. All my 
 debts to other friends in the University added together are not com- 
 parable to what I owe to the late Dean. 
 
 Latterly I need not say that I owed much to him and that I owe 
 much to you for your kind notice of my two sons, even since the sad 
 event which has put it out of his power to do more. 
 
AT CAMBRIDGE OBSERVATORY. 121 
 
 In the past summer, looking to my custom of making a visit to 
 Cambridge in some part of the October Term, I had determined that 
 a visit to Ely this year should not depend on the chance of being 
 free to leave Cambridge, but that, if it should be found convenient 
 to yourself and the Dean, the first journey should be made to Ely. 
 I wish that I had formed the same resolution one or two years ago. 
 
 With many thanks for your kindness, and with deep sympathy on 
 this occasion, 
 
 I am, 
 My dear Madam, 
 
 Yours very faithfully, 
 
 G. B. AIRY. 
 
 Sheepshanks was a Fellow of Trinity, in orders : he was 
 probably seven years older than Airy (he took his degree in 
 1816). He was not one of Airy's earliest friends, but he had 
 a great taste and liking for astronomy, and the friendship 
 between them when once established became very close. He 
 was a very staunch and fearless friend, an able and incisive 
 writer, and remarkably energetic and diligent in astronomical 
 investigations. He, or his sister, Miss Sheepshanks, had a 
 house in London, and Sheepshanks was very much in London, 
 and busied himself extremely with the work of the Royal 
 Observatory, that of the Board of Longitude, and miscella- 
 neous astronomical matters. He was most hospitable to his 
 friends, and while Airy resided at Cambridge his house was 
 always open to receive him on his frequent visits to town. 
 In the various polemical discussions on scientific matters in 
 which Airy was engaged, Sheepshanks was an invaluable 
 ally, and after Airy's removal to Greenwich had more or less 
 separated him from his Cambridge friends, Sheepshanks was 
 still associated with him and took a keen interest in his 
 Greenwich work. And this continued till Sheepshanks's 
 death. The warmest friendship always subsisted between 
 the family at the Observatory and Mr and Miss Sheep- 
 shanks. 
 
122 GEORGE BIDDELL AIRY. 
 
 There were many other friends, able and talented men, 
 but these four were the chief, and it is curious to note that 
 they were all much older than Airy. It would seem as if 
 Airy's knowledge had matured in* so remarkable a manner, 
 and the original work that he produced was so brilliant and 
 copious, that by common consent he ranked with men who 
 were much his seniors : and the natural gravity and decorum 
 of his manners when quite a young man well supported the 
 idea of an age considerably greater than was actually the 
 case. 
 
CHAPTER V. 
 
 AT GREENWICH OBSERVATORY 1836 TO 1846. 
 
 1S36 
 
 " THROUGH the last quarter of 1835 I had kept everything 
 going on at the Greenwich Observatory in the same manner 
 in which Mr Pond had carried it on. With the beginning of 
 1836 my new system began. I had already prepared 30 
 printed skeleton forms (a system totally unknown to Mr 
 Pond) which were now brought into use. And, having seen 
 the utility of the Copying Press in merchants' offices, I 
 procured one. From this time my correspondence, public 
 and private, is exceedingly perfect. 
 
 "At this time the dwelling house was still unconnected 
 with the Observatory. It had no staircase to the Octagon 
 Room. Four new rooms had been built for me on the 
 western side of the dwelling house, but they were not yet 
 habitable. The North-east Dome ground floor was still a 
 passage room. The North Terrace was the official passage 
 to the North-west Dome, where there was a miserable 
 Equatoreal, and to the 25 -foot Zenith Tube (in a square 
 tower like a steeple, which connected the N.W. Dome with 
 Flamsteed's house). The southern boundary of the garden 
 ran down a hollow which divides the peninsula from the site 
 of the present Magnetic Observatory, in such a manner that 
 the principal part of the garden was fully exposed to the 
 public. The Computing Room was a most pitiful little room. 
 There was so little room for me that I transported the 
 principal table to a room in my house, where I conducted 
 
124 GEORGE BIDDELL AIRY. 
 
 much of my own official business. A large useless reflecting 
 telescope (Ramage's), on the plan and nearly of the size of 
 Sir W. Herschel's principal telescope, encumbered the centre 
 of the Front Court. 
 
 " On Jan. I ith I addressed Mr Buck, agent of the Princess 
 Sophia of Gloucester, Ranger of Greenwich Park, for leave to 
 enclose a portion of the ground overlooking "my garden. 
 This was soon granted, and I was partially delivered from 
 the inconvenience of the public gaze. The liberation was not 
 complete till the Magnetic ground was enclosed in 1837. 
 
 " In the inferior departments of the Admiralty, especially 
 in the Hydrographic Office (then represented by Captain 
 Beaufort) with which I was principally connected, the Ob- 
 servatory was considered rather as a place for managing 
 Government chronometers than as a place of science. The 
 preceding First Assistant (Taylor) had kept a book of letter 
 references, and I found that out of 840 letters, 820 related to 
 Government chronometers only. On Jan. I7th I mentally 
 sketched my regulations for my own share in chronometer 
 business. I had some correspondence with Captain Beaufort, 
 but we could not agree, and the matter was referred to the 
 Admiralty. Finally arrangements were made which put the 
 chronometer business in proper subordination to the scientific 
 charge of the Observatory. 
 
 " In my first negociations with the Admiralty referring to 
 acceptance of the office of Astronomer Royal, in 1834, Lord 
 Auckland being then First Lord of the Admiralty, I had stipu- 
 lated that, as my successor at Cambridge would be unprepared 
 to carry on my Lectures, I should have permission to give a 
 final course of Lectures there. At the end of 1835 Lord 
 Auckland was succeeded by Lord Minto : I claimed the 
 permission from him and he refused it. When this was 
 known in Cambridge a petition was presented by many 
 Cambridge residents, and Lord Minto yielded. On April 
 1 8th I went to Cambridge with my wife, residing at the Bull 
 Inn, and began Lectures on April 2ist: they continued 
 
AT GREENWICH OBSERVATORY. 125 
 
 (apparently) to May 27th. My lecture-room was crowded 
 (the number of names was no) and the lectures gave great 
 satisfaction. I offered to the Admiralty to put all the profits 
 in their hands, and transmitted a cheque to the Accountant 
 General of the Navy : but the Admiralty declined to receive 
 them. 
 
 " On June 4th the Annual Visitation of the Observatory 
 was held, Mr F. Baily in the Chair. I presented a written 
 Report on the Observatory (a custom which I had introduced 
 at Cambridge) in which I did not suppress the expression of 
 my feelings about chronometer business. The Hydrographer, 
 Captain Beaufort, who was one of the Official Visitors, was 
 irritated : and by his influence the Report was not printed. 
 I kept it and succeeding Reports safe for three years, and 
 then the Board of Visitors agreed to print them ; and four 
 Reports were printed together, and bound with the Greenwich 
 Observations of 1838. 
 
 " In the course of this year I completed the volume of 
 Observations made at Cambridge Observatory in 1835 and 
 on Nov. loth the printed copies were distributed. About the 
 end of 1835 the Dome for the Northumberland Telescope was 
 erected : but apparently the polar frame was not erected." 
 
 The following account of an accident which occurred 
 during the construction of the dome is extracted from a 
 letter by Airy to his wife dated 1836 Jan. 3ist. "The 
 workmen's account of the dome blowing off is very curi- 
 ous : it must have been a strange gust. It started suddenly 
 when the men were all inside and Beaumont was looking 
 up at it : the cannon balls were thrown in with great violence 
 (one of them going between the spokes of Ransomes' large 
 casting), and instantly after the dome had started, the boards 
 of the outside scaffolding which had been tossed up by the 
 same gust dropped down into the gap which the dome had 
 left. It is a wonder that none of the men were hurt and that 
 the iron was not broken. The dome is quite covered and I 
 think does not look so well as when the hooping was visible." 
 
126 GEORGE BIDDELL AIRY. 
 
 " Previous to 1836 I had begun to contemplate the attach- 
 ment of Magnetic Observations to the Observatory, and had 
 corresponded with Prof. Christie, Prof. Lloyd, Prof. J. D. 
 Forbes, and Mr Gauss on the subject. On Jan. I2th 1836 I 
 addressed a formal letter to the Admiralty, and on Jan. i8th 
 received their answer that they had referred it to the Board 
 of Visitors. On March 25th I received authority for the 
 expenditure of 30, and I believe that I then ordered Merz's 
 2-foot magnet. The Visitors met on Feb. 26th and after 
 some discussion the site was chosen and the extent of ground 
 generally defined, and on Dec. 22nd Mr Spring Rice (Lord 
 Monteagle) as Chancellor of the Exchequer virtually effected 
 the transfer of the ground. But no further steps were taken 
 in 1836. A letter on a systematic course of magnetic obser- 
 vations in various parts of the world was addressed by Baron 
 Alexander Humboldt to the Duke of Sussex, President of the 
 Royal Society: and was referred to Prof. Christie and me. 
 We reported on it on June gth 1836, strongly recommending 
 the adoption of the scheme. 
 
 "A plan had been proposed by the Promoters of the 
 London and Gravesend Railway (Col. Landman, Engineer) 
 for carrying a railway at high level across the bottom of the 
 Park. On Jan. Qth I received orders from the Admiralty to 
 examine into its possible effect in producing vibrations in the 
 Observatory. After much correspondence, examination of 
 ground, &c., I fixed upon a part of the Greenwich Railway 
 (not yet opened for traffic) near the place where the Croydon 
 trunk line now joins it, as the place for trains to run upon, 
 while I made observations with a telescope viewing a col- 
 limator by reflection in mercury at the distance of 500 feet. 
 The experiments were made on Jan. 25th, and I reported on 
 Feb. 4th. It was shewn that there would be some danger to 
 the Observatory. On Nov. 2nd Mr James Walker, Engineer, 
 brought a model of a railway to pass by tunnel under the 
 lower part of the Park : apparently this scheme was not 
 pressed. 
 
AT GREENWICH OBSERVATORY. 
 
 " In addition to the routine work of the Observatory, a 
 special set of observations were made to determine the mass 
 of Jupiter. Also the Solar Eclipse of May I5th was observed 
 at Greenwich in the manner which I had introduced at Cam- 
 bridge. The Ordnance Zenith Sector, and the instruments for 
 the St Helena Observatory were brought for examination. 
 Much attention was given to chronometers, and various steps 
 were taken for their improvement. I had some important 
 correspondence with Mr (Sir John) Lubbock, upon the Lunar 
 Theory generally and his proposed empirical lunar tables. 
 This was the first germ of the great reduction of Lunar 
 Observations which I subsequently carried out. In October 
 I was nominated on the Council of the Royal Society, having 
 been admitted a Fellow on Feb. i8th 1836. I was President 
 of the Astronomical Society during this and the preceding 
 year (1836 and 1835). 
 
 " My connection with Groombridge's Catalogue of Stars 
 began in 1832, and the examination, in concert with Mr 
 Baily, of the edition printed by Mr Henry Taylor, resulted in 
 its condemnation. In 1834 I volunteered to the Admiralty 
 to prepare a new edition, and received their thanks and their 
 authority for proceeding. It required a great deal of ex- 
 amination of details, and much time was spent on it in 
 1836: but it was not brought to the state of readiness for 
 press. 
 
 "My predecessor, Mr Pond, died on Sept. 7th 1836, and 
 was interred in Halley's tomb in Lee churchyard." 
 
 The following letter was written by Airy in support of 
 the application for a pension to Mrs Pond, who had been left 
 in great distress : 
 
 To HENRY WARBURTON, ESQ. 
 
 " The points upon which in my opinion Mr Pond's claims to the 
 gratitude of Astronomers are founded, are principally the following. 
 First and chief, the accuracy which he introduced into all the princi- 
 
128 GEORGE BIDDELL AIRY. 
 
 pal observations. This is a thing which from its nature it is extremely 
 difficult to estimate now, so long after the change has been made, 
 and I can only say that so far as I can ascertain from books the 
 change is one of very great extent j for certainty and accuracy, 
 Astronomy is quite a different thing- from what it was, and this is 
 mainly due to Mr Pond. The most striking exemplification of this 
 is in his laborious working out of every conceivable cause or indica- 
 tion of error in the Circle and the two Circles : but very great praise 
 is also due for the new system which he introduced in working the 
 Transit. In comparing Mr Pond's systems of observation with Dr 
 Maskelyne's, no one can avoid being impressed with the inferiority 
 of Dr Maskelyne's. It is very important to notice that the conti- 
 nental observatories which have since attracted so much attention did 
 not at that time exist or did not exist in vigour. Secondly ', the atten- 
 tion bestowed by Mr Pond on those points (chiefly of sidereal astro- 
 nomy) which he regarded as fundamental : to which such masses of 
 observations were directed as entirely to remove the doubts from 
 probable error of individual observations or chance circumstances 
 which have injured many other determinations. Thirdly ', the regu- 
 larity of observation. The effect of all these has been that, since the 
 commencement of Mr Pond's residence at Greenwich, Astronomy 
 considered as an accurate representation of the state of the heavens 
 in the most material points has acquired a certainty and an extent 
 which it never had before. There is no period in the history of the 
 science so clean. On some matters (in regard to the choice of 
 observations) I might say that my own judgment would have differed 
 in some degree from Mr Pond's, but one thing could have been 
 gained only by giving up another, and upon the general accuracy no 
 improvement could have been made. Mr Pond understood nothing 
 of physical astronomy ; but neither did anybody else, in England. 
 
 The supposed decrease of general efficiency in the last few years 
 is to be ascribed to the following causes : 
 
 1. Mr Pond's ill health. 
 
 2. The inefficiency of his first assistant. 
 
 3. The oppression of business connected with chronometers. 
 The last of these, as I have reason to think, operated very far. 
 
 Business of this nature which (necessarily) is daily and peremptory 
 will always prevail over that which is general and confidential. I will 
 not trouble you with an account of the various ways in which the 
 chronometer business teazed the Astronomer Royal (several altera- 
 tions having been made at my representation), but shall merely 
 
AT GREENWICH OBSERVATORY. 129 
 
 remark that much of the business had no connection whatever with 
 astronomy. 
 
 " I beg to submit these remarks to your perusal, requesting you to 
 point out to me what part of them should be laid before any of the 
 King's Ministers, at what time, in what shape, and to whom addressed. 
 I am quite sure that Mrs Pond's claims require nothing to ensure 
 favourable consideration but the impression of such a feeling of Mr 
 Pond's astronomical merits as must be entertained by any reasonable 
 astronomer; and I am most anxious to assist in conveying this 
 impression." 
 
 " Of private history : I went to Suffolk for a week on Mar. 
 25th. On Sept. igth my son Wilfrid (my fourth child) was 
 born. In October I made an excursion for a week round the 
 coast of Kent. In November I went to my brother's house 
 at Keysoe in Bedfordshire : I was much exposed to cold on 
 the return-journey, which probably aggravated the illness 
 that soon followed. From Nov. 2/th I was ill ; made the 
 last journal entry of the year on Dec. 6th ; the next was on 
 Jan. I4th, 1837. I find that in this year I had introduced 
 Arthur Biddell to the Tithe Commutation Office, where he 
 was soon favourably received, and from which connection he 
 obtained very profitable employment as a valuer/' 
 
 1837 
 
 " My connection with Cambridge Observatory was not yet 
 finished. I had determined that I would not leave a figure 
 to be computed by my successor. In October I had (at my 
 private expense) set Mr Glaisher to work on reducing the 
 observations of Sun, Moon, and Planets made in 1833, 1834, 
 1835; and subsequently had the calculations examined by 
 Mr Hartnup. This employed me at times through 1837. I 
 state here, once for all, that every calculation or other work 
 in reference to the Cambridge Observatory, in this and sub- 
 sequent years, was done at my private expense. The work 
 of the Northumberland Telescope was going on through the 
 year : from Nov. 24th to 29th I was at Cambridge on these 
 works. 
 
 A. B. g 
 
130 GEORGE BIDDELL AIRY. 
 
 "An object-glass of 6f inches aperture (a most unusual 
 size at this time, when it was difficult to find a 4-inch or 
 5 -inch glass) had been presented to the Greenwich Observa- 
 tory by my friend Mr Sheepshanks, and on Mar. 2Qth I 
 received from the Admiralty authority for mounting it equa- 
 toreally in the empty South Dome, which had been intended 
 for a copy of the Palermo Circle. In the month of July the 
 Admiralty wished for my political assistance in a Greenwich 
 election, but I refused to give any. On Jan. 3rd I gave 
 notice to the Admiralty that I had finished the computations 
 of Groombridge's Catalogue, and was ready to print. The 
 printing was authorized and proceeded (the introduction 
 was finished on Nov. 22nd), but the book was not quite ready 
 till the beginning of 1838. In connection with the Cavendish 
 experiment: on June loth I wrote to Spring Rice (Chan- 
 cellor of the Exchequer) for 500, which was soon granted : 
 and from this time there is a great deal of correspondence 
 (mainly with Mr Baily) upon the details of the experiment 
 and the theory of the calculation. On July 24th I saw the 
 descent of the parachute by which Mr Cocking was killed. 
 I attended the coroner's inquest and gave evidence a few 
 days later. 
 
 "The Planetary Reductions from 1750 to 1830 had been 
 going on : the computers (Glaisher, Hartnup, and Thomas) 
 worked in the Octagon Room, and considerable advance was 
 made. In consequence of the agitation of the proposal by 
 Mr Lubbock to form empirical tables of the Moon, for which 
 I proposed to substitute complete reduction of the observa- 
 tions of the Moon from 1750, the British Association at York 
 (Oct. 23rd, 1837) appointed a deputation (including myself) 
 to place the matter before the Government. I wrote on the 
 matter to Mr Wood (Lord Halifax) stating that it would be 
 proper to raise the First Assistant's salary, and to give me 
 more indefinite power about employing computers. In all 
 these things I received cordial assistance from Mr Wood. 
 The Chancellor of the Exchequer (Mr Spring Rice) received 
 
AT GREENWICH OBSERVATORY. 131 
 
 us on Dec. 2Oth : statements were furnished by me, and the 
 business was sanctioned immediately. During this year I 
 was very much engaged in correspondence with Lubbock 
 and others on improvements of the Lunar Theory. 
 
 "In the operations of 1836 and 1837 a great quantity of 
 papers had been accumulated. I had kept them in reason- 
 ably good order, tied up in bundles : but this method began 
 to fail in convenience, as the number increased. The great 
 lines of classification were however now well understood. I 
 believe it was in the latter part of the year 1837 that I 
 finally settled on the principle of arranging papers in packets 
 and subordinate packets, every paper being flat, by the use 
 of four punched holes in every paper. I have never seen any 
 principle of arrangement comparable to this. It has been 
 adopted with the greatest ease by every assistant, and is used 
 to the present time (1871) without alteration. 
 
 " On Jan. 3rd I was informed unofficially by Mr Wood 
 (Admiralty Secretary) that the addition of the Magnetic 
 Ground was sanctioned. On Feb. 1 6th Mr Rhodes (an 
 officer of the Department of Woods and Works) came to put 
 me formally in possession of the ground. Between Apr. 26th 
 and May I3th the ground was enclosed, and my garden was 
 completely protected from the public. The plan of the build- 
 ing was settled, and numerous experiments were made on 
 various kinds of concrete : at last it was decided to build 
 with wood. 
 
 "After a dinner given by Lord Burlington, Chancellor, 
 the first meeting of the London University was held on 
 Mar. 4th, and others followed. On Apr. i8th I handed to 
 the Chancellor a written protest against a vote of a salary of 
 1000 to the Registrar: which salary, in fact, the Govern- 
 ment refused to sanction. Dissensions on the question of 
 religious examination were already beginning, but I took 
 little part in them. 
 
 " In 1833 Mr Henderson had resigned the superintendance 
 of the Cape of Good Hope Observatory, and Mr Maclear 
 
 92 
 
132 GEORGE BIDDELL AIRY. 
 
 was appointed. I recommended the same Official Instruc- 
 tions for him (they had included an allusion to La Caille's 
 Arc of Meridian) with an addition on the probability of 
 Trigonometrical Survey, on Aug*. 8th, 1837. On Feb. 24th, 
 1837, I wrote to Beaufort suggesting that Bradley's Sector 
 should be used for verifying the astronomical determinations, 
 and subsequently received the approval of the Admiralty. 
 In June Sir J. Herschel and I had an interview with Mr 
 Wood on the Cape equipment generally. The Sector was 
 erected with its new mounting, careful drawings were made 
 of every part, instructions were prepared for its use, and on 
 Aug. loth it was sent to Woolwich Dockyard and shipped 
 for the Cape. 
 
 "Of private history: On Aug. 23rd I started with my 
 wife for an excursion in South Wales, &c. On Sept. Qth I 
 gave a lecture in the Town Hall of Neath. While at Swansea 
 we received news of the death of my wife's father, the Rev. 
 Richard Smith, and returned at once. In this year Arthur 
 Biddell bought the little Eye estate for me." 
 
 1838 
 
 "Cambridge Observatory : On Dec. 29th, 1837, I had set 
 Mr Glaisher to work in collecting the annual results for 
 star-places from the Cambridge Observations, to form one 
 catalogue: I examined the calculations and the deduced 
 catalogue, and on Dec. 14, 1838, presented it to the Royal 
 Astronomical Society, under the title of 'The First Cam- 
 bridge Catalogue.' For the Northumberland telescope I was 
 engaged with Simms about the clockwork from time to time 
 up to Apr. 3Oth, and went to Cambridge about it. The 
 instrument was brought to a useable state, but some small 
 parts were still wanting. 
 
 " At Greenwich : In April I drew up a little history of 
 the Observatory for the Penny Cyclopaedia. On June 3Oth 
 the Lords of the Admiralty paid a short visit to the Observa- 
 
AT GREENWICH OBSERVATORY. 133 
 
 tory : on this occasion Mr Wood suggested a passage con- 
 necting the Observatory with the dwelling-house, and I 
 subsequently prepared sketches for it; it was made in the 
 next year. In the course of the year the Sheepshanks 
 Equatoreal was mounted, and Encke's Comet was observed 
 with it from Oct. 26th to Nov. 1 3th. On Mar. 3ist, &c. I 
 reported to the Admiralty on the selection of chronometers 
 for purchase, from a long list : this was an important begin- 
 ning of a new system. The Magnetic Observatory was built, 
 in the form originally planned for it (a four-armed cross with 
 equal arms, one axis being in the magnetic meridian) in the 
 beginning of this year. (No alteration has since been made in 
 form up to the present time, 1871, except that the north arm 
 has been lengthened 8 feet a few years ago.) On May 2ist a 
 magnet was suspended for the first time, Mr Baily and Lieut, 
 (afterwards Sir William) Denison being present. Groom- 
 bridge's Catalogue was finished, and on Mar. 3rd I arranged 
 for sending out copies. The Planetary Reductions were 
 carried on vigorously. On May 3 1st, 1838, the Treasury 
 assented to the undertaking of the Lunar Reductions and 
 allotted 2,000 for it : preparations were made, and in the 
 autumn 7 computers were employed upon it. It will easily 
 be seen that this undertaking added much to my labours and 
 cares. The geodetic afifairs of the Cape of Good Hope began 
 to be actively pressed, and in February Beaufort wrote to me 
 in consequence of an application from Maclear, asking about 
 a standard of length for Maclear (as foundation for a geodetic 
 survey). I made enquiries, and on Mar. I3th wrote to Mr 
 Wood, alluding also generally to the want of a National 
 English standard after the destruction of the Houses of 
 Parliament. On Apr. 24th the Admiralty sanctioned my 
 procuring proper Standard Bars. In connection with the 
 Cavendish Experiment, I have an immense quantity of corre- 
 spondence with Mr Baily, and all the mathematics were 
 furnished by me: the experiment was not finished at the end 
 of the year. The Perturbations of Uranus were now attract- 
 
134 GEORGE BIDDELL AIRY. 
 
 ing attention. I had had some correspondence on this subject 
 with Dr Hussey in 1834, and in 1837 with Eugene Bouvard. 
 On Feb. 24th, of 1838, I wrote to Schumacher regarding the 
 error in the tabular radius-vector;"of Uranus, which my mode 
 of reducing the observations enabled me to see. 
 
 " The National Standards of Length and Weight had been 
 destroyed in the fire of the Houses of Parliament. On May 
 nth I received a letter from Mr Spring Rice, requesting me 
 to act (as chairman) with a committee consisting of F. Baily, 
 J. E. Drinkwater Bethune, Davies Gilbert, J. G. S. Lefevre, 
 J. W. Lubbock, G. Peacock, and R. Sheepshanks, to report 
 on the steps now to be taken. I accepted the charge, and the 
 first meeting was held at the Observatory on May 22nd ; all 
 subsequent meetings in London, usually in the apartments of 
 the Royal Astronomical Society. I acted both as chairman 
 and as working secretary. Our enquiries went into a very 
 wide field, and I had much correspondence. 
 
 "On Jan. 4th Mr Wood wrote to me, mentioning that 
 Capt. Johnson had made some observations on the magnetism 
 of iron ships, and asking whether they ought to be continued ; 
 a steamer being offered at 50 per week. I applied to Beau- 
 fort for a copy of Johnson's Observations, and on Jan. 7th 
 replied very fully, discouraging such observations ; but recom- 
 mending a train of observations expressly directed to theo- 
 retical points. On Feb. I7th I reported that I had examined 
 the Deptford Basin, and found that it would do fairly well for 
 experiments. On July I4th, 1838, Capt. Beaufort wrote to me 
 that the Admiralty wished for experiments on the ship, the 
 ' Rainbow,' then in the river, and enquired whether I would 
 undertake them and what assistance I desired, as for instance 
 that of Christie or Barlow. I replied that one person should 
 undertake it, either Christie, Barlow, or myself, and that a 
 basin was desirable. On July i6th and I7th I looked at the 
 basins of Woolwich and Deptford, approving the latter. On 
 July 2 ist the Admiralty gave me full powers. From July 23rd 
 I was almost entirely employed on preparations. The course 
 
AT GREENWICH OBSERVATORY. 135 
 
 of operations is described in my printed Paper : the original 
 maps, curves, and graphical projections, are in the bound 
 MSS. : ' Correction of Compass in Iron Ships " Rainbow," ' at 
 the Greenwich Observatory. The angular disturbances were 
 found on July 26th and 3Oth, requiring some further work on 
 a raft, so that they were finally worked out on Aug. nth. I 
 struggled hard with the numbers, but should not have suc- 
 ceeded if it had not occurred to me to examine the horizontal 
 magnetic intensities. This was done on Aug. I4th, and the 
 explanation of the whole was suggested at once : graphical 
 projections were made on Aug. i6th and I7th for comparison 
 of my explanation with observations, and the business was 
 complete. On Aug. I7th and i8th I measured the intensity 
 of some magnets, to be used in the ship for correction. It is 
 to be remarked that, besides the effect of polar magnetism, 
 there was no doubt of the existence of an effect of induced 
 magnetism requiring correction by other induced magnetism : 
 and experiments for this were made in the Magnetic Obser- 
 vatory. All was ready for trial : and on Aug. 2oth I carried 
 my magnets and iron correctors to Deptford, mounted them 
 in the proper places, tried the ship, and the compass, which 
 had been disturbed 50 degrees to the right and 50 degrees to 
 the left, was now sensibly correct. On Aug. 2ist I reported 
 this to the Admiralty, and on Aug. 24th I tried the ship to 
 Gravesend. On Aug. 3Oth I had the loan of her for an ex- 
 pedition with a party of friends to Sheerness, and on Sept. 9th 
 I accompanied her to Gravesend, on her first voyage to Ant- 
 werp. On Oct. 5th application was made to me by the owner 
 of the * Ironsides ' to correct her compasses. In consequence 
 of this I went to Liverpool on Oct. 25th, and on this occasion 
 made a very important improvement in the practical mode of 
 performing the correction. On Nov. i6th I reported to the 
 Admiralty in considerable detail. On Dec. 4th I had an 
 interview with Lord Minto (First Lord of the Admiralty) and 
 Mr Wood. They refused to sanction any reward to me. 
 The following is a copy of the report of the Captain of the 
 
136 GEORGE BIDDELL AIRY. 
 
 ' Rainbow ' after her voyage to Antwerp : ' Having had the 
 command of the Rainbow steamer the two voyages between 
 London and Antwerp, I have the pleasure to inform you that 
 I am perfectly satisfied as to the Correctness of the compasses, 
 and feel quite certain they will continue so. I took particular 
 notice from land to land from our departure and found the 
 bearings by compass to be exact.'" The following extracts 
 from letters to his wife refer to the " Ironsides " : on Oct. 28th 
 1838 he writes, " I worked up the observations so much as to 
 see that the compass disturbance is not so great as in the 
 'Rainbow' (35 instead of 50), but quite enough to make 
 the vessel worthless ; and that it is quite different in direction 
 from that in the ' Rainbow ' so that if they had stolen one 
 of the ' Rainbow ' correctors and put it into this ship it would 
 have been much worse than before." And on Nov. ist he 
 writes, " On Wednesday I again went to the ship and tried 
 small alterations in the correctors : I am confident now that 
 the thing is very near, but we were most abominably baffled 
 by the sluggishness of the compass." 
 
 " The University of London : On Jan. 6th I attended a 
 sub-committee meeting on the minimum of acquirements for 
 B.A. degree, and various meetings of the Senate. On July 
 1 4th I intimated to Mr Spring Rice my wish to resign. I 
 had various correspondence, especially with Mr Lubbock, and 
 on Dec. I3th I wrote to him on the necessity of stipends to 
 Members of Senate. The dissensions on religious examina- 
 tion became very strong. I took a middle course, demanding 
 examination in the languages and books, but absolutely re- 
 fusing to claim any religious assent. I expressed this to Dr 
 Jerrard, the principal representative on the religious side, by 
 calling on him to substitute the words ' Recognition of Chris- 
 tian Literature ' for ' Recognition of Christian Religion ' : I 
 addressed a printed letter to Lord Burlington (Chancellor) 
 and the Members of the Senate, on this subject. 
 
 " Of private history : In January I made a short excur- 
 sion in Norfolk and Suffolk, and visited Prof. Sedgwick at 
 
AT GREENWICH OBSERVATORY. 137 
 
 Norwich. In April I paid a short visit to Mr Courtney at 
 Sanderstead, with my wife. On June I4th my son Hubert 
 was born. In September I went with my sister by Cam- 
 bridge, &c., to Luddington, where I made much enquiry 
 concerning my father and the family of Airy who had long 
 been settled there. We then visited various places in York- 
 shire, and arrived at Brampton, near Chesterfield, where Mrs 
 Smith, my wife's mother, now resided. And returned by 
 Rugby. I had much correspondence with my brother and 
 for him about private pupils and a better church living. 
 I complained to the Bishop of Norwich about the mutilation 
 of a celebrated monument in Playford Church by the incum- 
 bent and curate." 
 
 The following extracts are from letters to his wife relating 
 to the above-mentioned journeys : 
 
 CLOSE, NORWICH. 
 
 1838, Jan. 21. 
 
 I do not know what degree of cold you may have had last night, 
 but here it was (I believe) colder than before thermometer close to 
 the house at 3. I have not suffered at all. However I do not 
 intend to go to Lowestoft. 
 
 BRAMPTON. 
 
 1838, Sept. 30th. 
 
 We began to think that we had seen enough of Scarborough, so 
 we took a chaise in the afternoon to Pickering, a small agricultural 
 town, and lodged in a comfortable inn there. On Wednesday morn- 
 ing at 8 we started by the railroad for Whitby, in a huge carriage 
 denominated the Lady Hilda capable of containing 40 persons or 
 more drawn by one horse, or in the steep parts of the railway by two 
 horses. The road goes through a set of defiles of the eastern moor- 
 lands of Yorkshire which are extremely pretty : at first woody and 
 rich, then gradually poorer, and at last opening on a black moor with 
 higher moors in sight : descending in one part by a long crooked 
 inclined plane, the carriage drawing up another load by its weight : 
 through a little tunnel : and then along a valley to Whitby. The 
 rate of travelling was about 10 miles an hour. Betsy declares that it 
 was the most agreeable travelling that she ever had. 
 
138 GEORGE BIDDELL AIRY. 
 
 Yesterday (Saturday) Caroline drove Betsy and Miss Barnes 
 drove me to Clay Cross to see the works at the great railroad tunnel 
 there. Coming from the north, the railroad passes up the Chester- 
 field valley close by the town, and continues up the same valley, till 
 it is necessary for it to enter the valley which runs the opposite way 
 towards Buttersley : the tunnel passes under the high ground between 
 these two vallies : so that it is in reality at the water-shed : it is to be 
 I think more than a mile long, and when finished 27 feet clear in 
 height, so it is a grand place. We saw the preparations for a blast, 
 and heard it fired : the ladies stopping their ears in due form. 
 
 1839 
 
 " Cambridge Observatory : On Mar. 7th I went to Cam- 
 bridge on the business of the Northumberland Telescope : I 
 was subsequently engaged on the accounts, and on Aug. i6th 
 I finally resigned it to Prof. Challis, who accepted it on 
 Aug. i pth. On Sept. nth I communicated its completion 
 and the settlement of accounts to the Duke of Northumber- 
 land. The total expense was 1938. gs. 2d.+ 15000 francs 
 for the object-glass. 
 
 " At Greenwich Observatory : On Jan. 3rd I received the 
 last revise of the 1837 Observations, and on Jan. 8th the first 
 sheet for 1838. In July I report on selection from a long list 
 of chronometers which had been on trial, and on Sept. 2nd I 
 pointed out to Capt Beaufort that the system of offering only 
 one price would be ruinous to the manufacture of chrono- 
 meters, and to the character of those supplied to the Admir- 
 alty : and that I would undertake any trouble of classifying 
 the chronometers tried. This letter introduced the system 
 still in use (1871), which has been most beneficial to the 
 manufacture. On Sept. nth I proposed that all trials begin 
 in the first week of January: this also has been in use as an 
 established system to the present time. It was pointed out 
 to me that a certain chronometer was affected by external 
 magnetic power. I remedied this by placing under it a free 
 compass magnet : a stand was specially prepared for it. I 
 
AT GREENWICH OBSERVATORY. 139 
 
 have never found another chronometer sensibly affected 
 by magnetism. In November and December I tried my new 
 double-image micrometer. Between May i6th and Oct. I3th 
 a fireproof room was constructed in the southern part of the 
 quadrant room ; and in November a small shed was erected 
 over the entrance to the North Terrace. The position of the 
 free Meridional Magnet (now mounted in the Magnetic 
 Observatory) was observed at every 5 m. through 24 hours 
 on Feb. 22nd and 23rd, May 24th and 25th, Aug. 3<Dth 
 and 3 ist, and Nov. 29th and 3Oth. This was done in co- 
 operation with the system of the Magnetic Union estab- 
 lished by Gauss in Germany. The Reduction of the 
 Greenwich Planetary and Lunar Observations, 1750 to 
 1830, went on steadily. I had six and sometimes seven 
 computers constantly at work, in the Octagon Room. As 
 in 1838 I had a great amount of correspondence with Mr 
 Baily on the Cavendish Experiment. I attended as regu- 
 larly as I could to the business of the University of London. 
 The religious question did not rise very prominently. I took 
 a very active part, and have a great deal of correspondence, 
 on the nature of the intended examinations in Hydrography 
 and Civil Engineering. On the Standards Commission the 
 chief work was in external enquiries. On June 6th I had 
 enquiries from John Quincey Adams (U. S. A.) on the 
 expense, &c., of observatories : an observatory was contem- 
 plated in America. I had correspondence about the proposed 
 establishment of observatories at Durham, Glasgow, and Liver- 
 pool. 
 
 " I had in this year a great deal of troublesome and on the 
 whole unpleasant correspondence with the Admiralty about 
 the correction of the compass in iron ships. I naturally ex- 
 pected some acknowledgment of an important service rendered 
 to Navigation : but the Admiralty peremptorily refused it. 
 My account of the Experiments &c. for the Royal Society 
 is dated April 9th. The general success of the undertaking 
 soon became notorious, and (as I understood) led immediately 
 
140 GEORGE BIDDELL AIRY. 
 
 to extensive building of iron ships : and it led also to applica- 
 tions to me for correction of compasses. On Jan. Qth I was 
 addressed in reference to the Royal Sovereign and Royal 
 George at Liverpool; July i8th tfee Orwell; May nth two 
 Russian ships built on the Thames ; Sept. 4th the ships of 
 the Lancaster Company. 
 
 "I had much work in connection with the Cape of Good 
 Hope Observatory, chiefly relating to the instrumental equip- 
 ment and to the geodetical work. As it was considered advis- 
 able that any base measured in the Cape Colony should be 
 measured with compensation bars, I applied to Major Jervis 
 for the loan of those belonging to the East Indian Survey, 
 but he positively refused to lend them. On Jan. 2Oth I 
 applied to Col. Colby for the compensation bars of the 
 British Survey, and he immediately assented to lending 
 them. Col. Colby had suggested to the Ordnance Depart- 
 ment that Capt. Henderson and several sappers should be 
 sent to use the measuring bars, and it was so arranged. 
 It still appeared desirable to have the command of some 
 soldiers from the Garrison of Cape Town, and this matter 
 was soon arranged with the military authorities by the 
 Admiralty. 
 
 " The following are the principal points of my private 
 history : it was a very sad year. On Jan. 24th I went with 
 my wife to Norwich, on a visit to Prof. Sedgwick, and in 
 June I visited Sir J. Herschel at Slough. On June I3th my 
 dear boy Arthur was taken ill : his malady soon proved to be 
 scarlet fever, of which hexiied on June 24th at 7 in the morn-- 
 ing. It was arranged that he should be buried in Playford 
 churchyard on the 28th, and on that day I proceeded to 
 Playford with my wife and my eldest son George Richard. 
 At Chelmsford my son was attacked with slight sickness, and 
 being a little unwell did not attend his brother's funeral. On 
 July ist at 4h. 15 m. in the morning he also died : he had 
 some time before suffered severely from an attack of measles, 
 and it seemed probable that his brain had suffered. On July 
 
AT GREENWICH OBSERVATORY. 141 
 
 5th he was buried by the side of his brother Arthur in Play- 
 ford churchyard. On July 23rd I went to Colchester on my 
 way to Walton-on-the-Naze, with my wife and all my family ; 
 all my children had been touched, though very lightly, with 
 the scarlet fever. It was near the end of this year that my 
 mother quitted the house (Luck's) at Playford, and came to 
 live with me at Greenwich Observatory, where she lived till 
 her death ; having her own attendant, and living in perfect 
 confidence with my wife and myself, and being I trust as 
 happy as her years and widowhood permitted. My sister 
 also lived with me at the Observatory." 
 
 1840 
 
 " In the latter part of 1839, and through 1840, I had much 
 correspondence with the Admiralty, in which I obtained a 
 complete account of the transfer of the Observatory from the 
 Ordnance Department to the Admiralty, and the transfer of 
 the Visitation of the Observatory from the Royal Society to 
 the present Board of Visitors. In 1840 I found that the 
 papers of the Board of Longitude were divided between the 
 Royal Society and the Admiralty : I obtained the consent of 
 both to bring them to the Observatory. 
 
 " In this year I began to arrange about an annual dinner 
 to be held at the Visitation. My double-image micrometer 
 was much used for observations of circumpolar double stars. 
 In Magnetism and Meteorology, certain quarterly observa- 
 tions were kept up ; but in November the system of incessant 
 eye-observations was commenced. I refused to commence 
 this until I had secured a ' Watchman's Clock ' for mechan- 
 ical verification of the regular attendance of the Assistants. 
 With regard to chronometers : In this year, for the first time, 
 I took the very important step of publishing the rates ob- 
 tained by comparisons at the Observatory. I confined myself 
 on this occasion to the chronometers purchased by the 
 Admiralty. In March a pigeon-house was made for expo- 
 
142 GEORGE BIDDELL AIRY. 
 
 sure of chronometers to cold. The Lunar and Planetary 
 Reductions were going on steadily. I was consulted about 
 an Observatory at Oxford, where I supported the introduc- 
 tion of the Heliometer. -The stipend of the Bakerian Lec- 
 ture was paid to me for my explanation of Brewster's new 
 prismatic fringes. The business of the Cape Observatory 
 and Survey occupied much of my time. In 1838 the Rev. 
 H. J. Rose (Editor of the Encyclopaedia Metropolitana) had 
 proposed my writing a Paper on Tides, &c. ; in Oct. 1840 I 
 gave him notice that I must connect Tides with Waves, and 
 in that way I will take up the subject. Much correspondence 
 on Tides, &c., with Whewell and others followed. 
 
 "With regard to the Magnetical and Meteorological Es- 
 tablishment. On June i8th Mr Lubbock reported from the 
 Committee of Physics of the Royal Society to the Council in 
 favour of a Magnetic and Meteorological Observatory near 
 London. After correspondence with Sheepshanks, Lord 
 Northampton, and Herschel, I wrote to the Council on July 
 9th, pointing out what the Admiralty had done at Greenwich, 
 and offering to cooperate. In a letter to Lord Minto I stated 
 that my estimate was 550, including ;ioo to the First 
 Assistant: Lubbock's was ^"3,000. On Aug. nth the Treasury 
 assented, limiting it to the duration of Ross's voyage. On 
 Aug. 1 7th Wheatstone looked at our buildings and was satis- 
 fied. My estimate was sent to the Admiralty, viz. 150 
 outfit, 520 annual expense ; and Glaisher to be Superin- 
 tendent. I believe this was allowed for the present ; for the 
 following year it was placed on the Estimates. Most of the 
 contemplated observations were begun before the end of 
 1840: as much as possible in conformity with the Royal 
 Society's plan. Mr Hind (subsequently the Superintendent 
 of the Nautical Almanac) and Mr Paul were the first extra 
 assistants. 
 
 " Of private history. On Feb. 2Qth I went to Cambridge 
 with my Paper on the Going Fusee. On Mar. 27th I went 
 to visit Mrs Smith, my wife's mother, at Brampton near 
 
AT GREENWICH OBSERVATORY. 143 
 
 Chesterfield. I made a short visit to Playford in April and 
 a short expedition to Winchester, Portsmouth, &c., in June. 
 From Sept. 5th to Oct. 3rd I was travelling in the North of 
 England and South of Scotland." [This was an extremely 
 active and interesting journey, in the course of which a great 
 number of places were visited by Airy, especially places on 
 the Border mentioned in Scott's Poems, which always had a 
 great attraction for him. He also attended a Meeting of the 
 British Association at Glasgow and made a statement regard- 
 ing the Planetary and Lunar Reductions : and looked at a site 
 for the Glasgow Observatory.] " In November I went for a 
 short time to Cambridge and to Keysoe (my brother's resi- 
 dence). On Dec. 26th my daughter Hilda was born (subse- 
 quently married to E. J. Routh). In this year I had a Ipss of 
 3 5 by a fi fe on mv Eye estate." 
 
 The following extracts are from letters to his wife. Some 
 of them relate to matters of general interest. They are all 
 of them characteristic, and serve to shew the keen interest 
 which he took in matters around him, and especially in archi- 
 tecture and scenery. The first letter relates to his journey 
 from Chesterfield on the previous day. 
 
 FLAMSTEED HOUSE, 
 
 1840, April 2. 
 
 I was obliged to put up with an outside place to Derby yester- 
 day, much against my will, for I was apprehensive that the cold 
 would bring on the pain in my face. Of that I had not much ; but 
 I have caught something of sore throat and catarrh. The coach 
 came up at about 22 minutes past 8. It arrived in Derby at 20 minutes 
 or less past u (same guard and coachman who brought us), and 
 drew up in the street opposite the inn at which we got no dinner, 
 abreast of an omnibus. I had to go to a coach office opposite the 
 inn to pay and be booked for London, and was duly set down in a 
 way-bill with name; and then entered the omnibus: was transferred 
 to the Railway Station, and then received the Railway Ticket by 
 shouting out my name. If you should come the same way, you 
 
144 GEORGE BIDDELL AIRY. 
 
 would find it convenient to book your place at Chesterfield to 
 London by your name (paying for the whole, namely, coach fare, 
 omnibus fare -/6, and railway fare i. 15^. od. first class). Then 
 you will only have to step out .of the co,ach into the omnibus, and to 
 scream out once or twice to the guard to make sure that you are 
 entered in the way-bill and that your luggage is put on the omnibus. 
 
 FLAMSTEED HOUSE, GREENWICH, 
 1840, April 15. 
 
 I forgot to tell you that at Lord Northampton's I saw some 
 specimens of the Daguerrotype, pictures made by the Camera 
 Obscura, and they surpass in beauty of execution anything that I 
 could have imagined. Baily who has two or three has promised to 
 lend them for your inspection when you return. Also I saw some 
 post-office stamps and stamped envelopes : I do not much admire 
 the latter. 
 
 The following relates to the fire on his Eye farm, referred 
 to above : 
 
 PLAYFORD, 
 
 1840, April 23. 
 
 On Wednesday (yesterday) went with my uncle to the Eye 
 Estate, to see the effects of the fire. The farming buildings of every 
 kind are as completely cleared -away as if they had been mown down: 
 not a bit of anything but one or two short brick walls and the brick 
 foundations of the barns and stacks. The aspect of the place is 
 much changed, because in approaching the house you do not see it 
 upon a back-ground of barns, &c., but standing alone. The house 
 is in particularly neat and good order. I did not think it at all 
 worth while to make troublesome enquiries of the people who reside 
 there, but took Mr Case's account. There seems no doubt that the 
 fire was caused by the maid-servant throwing cinders into a sort of 
 muck-place into which they had been commonly thrown. I suppose 
 there was after all this dry weather straw or muck drier than usual, 
 and the cinders were hotter than usual. The whole was on fire in 
 an exceedingly short time ; and everything was down in less than an 
 hour. Two engines came from Eye, and all the population of the 
 
AT GREENWICH OBSERVATORY. 145 
 
 town (as the fire began shortly after two o'clock in the afternoon). 
 It is entirely owing to these that my house, and the farm (SewelPs) 
 on the opposite side of the road, were not burned down. At the 
 beginning of the fire the wind was N.E. which blew directly towards 
 the opposite farm (Sewell's) : although the nearest part of it (tiled 
 dwelling house) was 100 yards off or near it, and the great barn 
 (thatched roof) considerably further, yet both were set on fire several 
 times. All this while, the tail of my house was growing very hot : 
 and shortly after the buildings fell in burning ruins, the wind changed 
 to N.W., blowing directly to my house. If this change had happened 
 while the buildings were standing and burning, there would have 
 been no possibility of saving the house. As it was, the solder is 
 melted from the window next the farm-yard, and the roof was set on 
 fire in three or four places. One engine was kept working on my 
 house and one on the opposite farm. A large pond was pretty 
 nearly emptied. Mr Case's horses and bullocks were got out, not 
 without great difficulty, as the progress of the fire was fearfully rapid. 
 A sow and nine pigs were burnt, and a large hog ran out burnt so 
 much that the people killed it immediately. 
 
 GEORGE INN, WINCHESTER, 
 1840, June 21. 
 
 At Winchester we established ourselves at the George and then 
 without delay proceeded to St Cross. I did not know before the 
 nature of its hospital establishment, but I find that it is a veritable 
 set of alms-houses. The church is a most curious specimen of the 
 latest Norman. I never saw one so well marked before Norman 
 ornaments on pointed arches, pilasters detached with cushion capitals, 
 and various signs : and it is clearly an instance of that state of the 
 style when people had been forced by the difficulties and inelegan- 
 cies of the round arch in groining to adopt pointed arches for groin- 
 ing but had not learnt to use them for windows This morning 
 
 after breakfast went to the Cathedral (looking by the way at a 
 curious old cross in the street). I thought that its inside was wholly 
 Norman, and was most agreeably surprised by finding the whole 
 inside groined in every part with excellent late decorated or perpen- 
 dicular work. Yet there are several signs about it which lead me to 
 think that the whole inside has been Norman, and even that the 
 pilasters now worked up into the perpendicular are Norman. The 
 transepts are most massive old Norman, with side-aisles running 
 
 A. B. 10 
 
146 GEORGE BIDDELL AIRY. 
 
 round their ends (which I never saw before). The groining of the 
 side aisles of the nave very effective from the strength of the cross 
 ribs. The clerestory windows of the quire very large. The organ is 
 on one side. But the best thing ..&bout the quire is the wooden 
 stall-work, of early decorated, very beautiful. A superb Lady Chapel, 
 of early English. 
 
 PORTSMOUTH, 
 
 1840, June 23. 
 
 We left Winchester by evening train to the Dolphin, Southamp- 
 ton, and slept there. At nine in the morning we went by steamboat 
 down the river to Ryde in the Isle of Wight : our steamer was going 
 on to Portsmouth, but we thought it better to land at Ryde and take 
 a boat for ourselves. We then sailed out (rather a blowing day) to 
 the vessel attending Col. Pasley's operations, and after a good deal 
 of going from one boat to another (the sea being so rough that our 
 boat could not be got up to the ships) and a good deal of waiting, 
 we got on board the barge or lump in which Col. Pasley was. Here 
 we had the satisfaction of seeing the barrel of gunpowder lowered 
 (there was more than a ton of gunpowder), and seeing the divers go 
 down to fix it, dressed in their diving helmets and supplied with air 
 from the great air-pump above. When all was ready and the divers 
 had ascended again, the barge in which we were was warped away, 
 and by a galvanic battery in another barge (which we had seen 
 carried there, and whose connection with the barrel we had seen), 
 upon signal given by sound of trumpet, the gunpowder was fired. 
 The effect was most wonderful. The firing followed the signal 
 instantaneously. We were at between 100 and 200 yards from the 
 place (as I judge), and the effects were as follows. As soon as the 
 signal was given, there was a report, louder than a musket but not so 
 loud as a small cannon, and a severe shock was felt at our feet, just 
 as if our barge had struck on a rock. Almost immediately, a very 
 slight swell was perceived over the place of the explosion, and the 
 water looked rather foamy : then in about a second it began to rise, 
 and there was the most enormous outbreak of spray that you can 
 conceive. It rose in one column of 60 or 70 feet high, and broad 
 at the base, resembling a stumpy sheaf with jagged masses of spray 
 spreading out at the sides, and seemed to grow outwards till I almost 
 feared that it was coming to us. It sunk, I suppose, in separate 
 
AT GREENWICH OBSERVATORY. 147 
 
 parts, for it did not make any grand squash down, and then there 
 were seen logs of wood rising, and a dense mass of black mud, which 
 spread gradually round till it occupied a very large space. Fish 
 were stunned by it : our boatmen picked up some. It was said by 
 all present that this was the best explosion which had been seen : it 
 was truly wonderful. Then we sailed to Portsmouth The explo- 
 sion was a thing worth going many miles to see. There were many 
 yachts and sailing boats out to see it (I counted 26 before they were 
 at the fullest), so that the scene was very gay. 
 
 Here are some notes on York Cathedral after the fire : 
 
 RED LION HOTEL, REDCAR, 
 1840, Sept. 7. 
 
 My first letter was closed after service at York Cathedral. As 
 soon as I had posted it, I walked sedately twice round the cathedral, 
 and then I found the sexton at the door, who commiserating me of 
 my former vain applications, and having the hope of lucre before his 
 eyes, let me in. I saw the burnt part, which looks not melancholy 
 but unfinished. Every bit of wood is carried away clean, with 
 scarcely a smoke-daub to mark where it has been : the building 
 looks as if the walls were just prepared for a roof, but there are 
 some deep dints in the pavement, shewing where large masses have 
 fallen. The lower parts of some of the columns (to the height of 
 8 or 10 feet) are much scaled and cracked. The windows are 
 scarcely touched. I also refreshed my memory of the chapter-house, 
 which is most beautiful, and which has much of its old gilding 
 reasonably bright, and some of its old paint quite conspicuous. And 
 I looked again at the old crypt with its late Norman work, and at 
 the still older crypt of the pre-existing church. 
 
 1841 
 
 " The routine work of the Observatory in its several 
 departments was carried on steadily during this year. The 
 Camera Obscura was removed from the N.W. Turret of the 
 Great Room, to make way for the Anemometer. In Mag- 
 
 10 2 
 
148 GEORGE BIDDELL AIRY. 
 
 netism and Meteorology the most important thing was the 
 great magnetic storm of Sept. 25th, which revealed a new 
 class of magnetic phenomena. It was very well observed by 
 Mr Glaisher, and I immediately printed and circulated an 
 account of it. In April I reported that the Planetary Reduc- 
 tions were completed, and furnished estimates for the print- 
 ing. In August I applied for 18,000 copies of the great 
 skeleton form for computing Lunar Tabular Places, which 
 were granted. I reported, as usual, on various Papers for 
 the Royal Society, and was still engaged on the Cavendish 
 Experiment. In the University of London I attended the 
 meeting of Dec. 8th, on the reduction of Examiners' salaries, 
 which were extravagant. I furnished Col. Colby with a plan 
 of a new Sector, still used in the British Survey. I appealed 
 to Colby about the injury to the cistern on the Great Gable 
 in Cumberland, by the pile raised for the Survey Signal. 
 On Jan. 3rd occurred a most remarkable tidal disturbance : 
 the tide in the Thames was 5 feet too low. I endeavoured 
 to trace it on the coasts, and had a vast amount of corre- 
 spondence: but it elicited little. 
 
 " Of private history : I was a short time in Suffolk in 
 March. On Mar. 3 1st I started with my wife (whose health 
 had suffered much) for a trip to Bath, Bristol, Cardiff, Swan- 
 sea, &c. While at Swansea we received news on Apr. 24th 
 of the deadly illness of my dear mother. We travelled by 
 Neath and Cardiff to Bath, where I solicited a rest for my 
 wife from my kind friend Miss Sutcliffe, and returned alone 
 to Greenwich. My dear mother had died on the morning of 
 the 24th. The funeral took place at Little Whelnetham 
 (near Bury) on May 1st, where my mother was buried by the 
 side of my father. We went to Cambridge, where my wife 
 consulted Dr Haviland to her great advantage, and returned 
 to Greenwich on May 7th. On May I4th to i6th I was at 
 Sanderstead (Rev. J. Courtney) with Whewell as one sponsor, 
 at the christening of my daughter Hilda. In September I 
 went for a trip with my sister to Yorkshire and Cumberland, 
 
AT GREENWICH OBSERVATORY. 149 
 
 in the course of which we visited Dent (Sedgwick's birth- 
 place), and paid visits to Mr Wordsworth, Miss Southey, and 
 Miss Bristow, returning to Greenwich on the 3Oth Sept. 
 From June I5th to iQth I visited my brother at Keysoe." 
 
 The following extracts are from letters written to his wife 
 while on the above trip in Yorkshire and Cumberland : 
 
 RED LION INN, REDCAR, 
 1841, Sept. ii. 
 
 We stopped at York : went to the Tavern Hotel. In the morn- 
 ing (Friday) went into the Cathedral. I think that it improves on 
 acquaintance. The nave is now almost filled with scaffolding for 
 the repair of the roof, so that it has not the bare unfinished appear- 
 ance that it had when I was there last year. The tower in which 
 the fire began seems to be a good deal repaired : there are new mul- 
 lions in its windows, &c. We stopped to hear part of the service, 
 which was not very effective. 
 
 Here are notes of his visit to Dentdale in Yorkshire, the 
 birthplace of his friend Sedgwick : 
 
 KING'S HEAD, KENDAL, 
 1841, Sept. 15. 
 
 The day was quite fine, and the hills quite clear. The ascent 
 out of Hawes is dull ; the little branch dale is simple and monoto- 
 nous, and so are the hills about the great dale which are in sight. 
 The only thing which interested us was the sort of bird's-eye view of 
 Hardraw dell, which appeared a most petty and insignificant opening 
 in the great hill side. But when we got to the top of the pass there 
 was a magnificent view of Ingleborough. The dale which was most 
 nearly in front of us is that which goes down to Ingleton, past the 
 side of Ingleborough. The mountain was about nine miles distant. 
 We turned to the right and immediately descended Dent-dale. The 
 three dales (to Hawes, to Ingleton, and to Dent) lay their heads 
 together in a most amicable way, so that, when at the top, it is 
 equally easy to descend down either of them. We found very soon 
 that Dent-dale is much more beautiful than that by which we had 
 ascended. The sides of the hills are steeper, and perhaps higher : 
 the bottom is richer. The road is also better. The river is a con- 
 
150 GEORGE BIDDELL AIRY. 
 
 tinued succession of very pretty falls, almost all of which have 
 scooped out the lower strata of the rock, so that the water shoots 
 clear over. For several miles (perhaps 10) it runs upon bare lime- 
 stone without a particle of earth. From the head of the dale to the 
 village of Dent is eight miles. At ;about half-way is a new chapel, 
 very neat, with a transept at its west end. The village of Dent is 
 one of the strangest places that I ever saw. Narrow street, up and 
 down, with no possibility of two carriages bigger'- than children's 
 carts passing each other. We stopped, at the head inn and enquired 
 about the Geolog: but he is not in the country. We then called 
 on his brother, who was much surprised and pleased to see us. His 
 wife came in soon after (his daughter having gone with a party to see 
 some waterfall) and they urged us to stop and dine with them. So 
 we walked about and saw every place about the house, church, and 
 school, connected with the history of the Geolog: and then dined. 
 I promised that you should call there some time when we are in the 
 north together and spend a day or two with them. Mr Sedgwick 
 says it is reported that Whewell will take Sedbergh living (which is 
 now vacant : Trinity College is patron). Then we had our chaise 
 and went to Sedbergh. The very mouth of Dent-dale is more con- 
 tracted than its higher parts. Sedbergh is embosomed among lump- 
 ing hills. Then we had another carriage to drive to Kendal. 
 
 Here is a recollection of Wordsworth : 
 
 SALUTATION, AMBLESIDE, 
 1841, Sept. 19. 
 
 We then got our dinner at Lowwood, and walked straight to 
 Ambleside, changed our shoes, and walked on to Rydal to catch 
 Wordsworth at tea. Miss Wordsworth was being drawn about in a 
 chair just as she was seven years ago. I do not recollect her appear- 
 ance then so as to say whether she is much altered, but I think not. 
 Mr Wordsworth is as full of good talk as ever, and seems quite 
 strong and well. Mrs Wordsworth looks older. Their son William 
 was at tea, but he had come over only for the day or evening. 
 There was also a little girl, who I think is Mrs Wordsworth's niece. 
 
AT GREENWICH OBSERVATORY. 151 
 
 1842 
 
 " In this year I commenced a troublesome work, the 
 Description of the Northumberland Telescope. On Sept. 
 9th I wrote to the Duke of Northumberland suggesting this, 
 sending him a list of Plates, and submitting an estimate of 
 expense 120. On Sept. iQth I received the Duke's assent. 
 I applied to Prof. Challis (at the Cambridge Observatory) 
 requesting him to receive the draughtsman, Sly, in his house, 
 which he kindly consented to do. 
 
 " With regard to Estimates. I now began to point out to 
 the Admiralty the inconvenience of furnishing separate esti- 
 mates, viz. to the Admiralty for the Astronomical Establish- 
 ment, and to the Treasury for the Magnetical and Meteoro- 
 logical Establishment. The great work of the Lunar 
 Reductions proceeded steadily : 14 computers were employed 
 on them. With regard to the Magnetical and Meteorological 
 Establishment : I suppose that James Ross's expedition had 
 returned : and with this, according to the terms of the original 
 grant, the Magnetical and Meteorological Establishments 
 expired. There was much correspondence with the Royal 
 Society and the Treasury, and ultimately Sir R. Peel con- 
 sented to the continuation of the establishments to the end 
 of 1845. In this year began my correspondence with Mr 
 Mitchell about the Cincinnati Observatory. On Aug. 25 Mr 
 Mitchell settled himself at Greenwich, and worked for a long 
 time in the Computing Room. And in this year Mr Aiken of 
 Liverpool first wrote to me about the Liverpool Observatory, 
 and a great deal of correspondence followed : the plans were 
 in fact entirely entrusted to me. July 7th was the day of the 
 Total Eclipse of the Sun, which I observed with my wife at 
 the Superga, near Turin. I wrote an account of my observa- 
 tions for the Royal Astronomical Society. On Jan. loth I 
 notified to Mr Goulburn that our Report on the Restoration 
 of the Standards was ready, and on Jan. I2th I presented it. 
 
152 GEORGE BIDDELL AIRY. 
 
 After this followed a great deal of correspondence, principally 
 concerning the collection of authenticated copies of the Old 
 Standards from all sides. In some discussions with Capt. 
 Shirreff, then Captain Superintendent of the Chatham Dock- 
 yard, I suggested that machinery might be made which 
 would saw ship-timbers to their proper form, and I sent him 
 some plans on Nov. 8th. This was the beginning of a corre- 
 spondence which lasted long, but which led to nothing, as 
 will appear hereafter. On Dec. I5th, being on a visit to 
 Dean Peacock at Ely, I examined the Drainage Scoop Wheel 
 at Prickwillow, and made a Report to him by letter, which 
 obtained circulation and was well known. On May 26th the 
 manuscript of my article, ' Tides and Waves,' for the Ency- 
 clopaedia Metropolitana was sent to the printer. I had exten- 
 sive correspondence, principally on local tides, with Whewell 
 and others. Tides were observed for me by Colby's officers 
 at Southampton, by myself at Christchurch and Poole, at 
 Ipswich by Ransome's man ; and a great series of observa- 
 tions of Irish Tides were made on my plan under Colby's 
 direction in June, July and August. On Sept. I5th Mr 
 Goulburn, Chancellor of the Exchequer, asked my opinion on 
 the utility of Babbage's calculating machine, and the pro- 
 priety of expending further sums of money on it. I replied, 
 entering fully into the matter, and giving my opinion that it 
 was worthless. I was elected an Honorary Member of the 
 Institution of Civil Engineers, London. 
 
 " The reduction and printing of the astronomical observa- 
 tions had been getting into arrear : the last revise of the 1840 
 observations went to press on May i8th, 1842. On Aug. 
 1 8th came into operation a new organization of Assistants' 
 hours of attendance, &c., required for bringing up reductions. 
 I worked hard myself and my example had good effect." His 
 reference to this subject in his Report to the Visitors is as 
 follows : " I have in one of the preceding articles alluded to 
 the backwardness of our reductions. In those which follow 
 it I trust that I have sufficiently explained it. To say nothing 
 
AT GREENWICH OBSERVATORY. 153 
 
 of the loss, from ill health, of the services of most efficient 
 assistants, I am certain that the quantity of current work will 
 amply explain any backwardness. Perhaps I may particu- 
 larly mention that in the observations of 1840 there was an 
 unusual quantity of equatoreal observations, and the reduc- 
 tions attending these occupied a very great time. But, as 
 regards myself, there has been another cause. The reduction 
 of the Ancient Lunar and Planetary Observations, the atten- 
 tion to chronometer constructions, the proposed management 
 of the printing of papers relating to important operations at 
 the Cape of Good Hope ; these and similar operations have 
 taken up much of my time. I trust that I am doing well in 
 rendering Greenwich, even more distinctly than it has been 
 heretofore, the place of reference to all the world for the 
 important observations, and results of observations, on which 
 the system of the universe is founded. As regards myself, I 
 have been accustomed, in these matters, to lay aside private 
 considerations ; to consider that I am not a mere Superin- 
 tendent of current observations, but a Trustee for the honour 
 of Greenwich Observatory generally, and for its utility gene- 
 rally to the world ; nay, to consider myself not as mere 
 Director of Greenwich Observatory, but (however unworthy 
 personally) as British Astronomer, required sometimes by my 
 office to interfere (when no personal offence is given) in the 
 concerns of other establishments of the State. If the Board 
 supports me in this view there can be little doubt that the 
 present delay of computations, relating to current observa- 
 tions, will be considered by them as a very small sacrifice to 
 the important advantage that may be gained by proper atten- 
 tion to the observations of other times and other places." 
 
 " Of private history : In February I went for a week to 
 Playford and Norwich, visiting Prof. Sedgwick at the latter 
 place. On Mar. ist my third daughter Christabel was born. 
 In March I paid a short visit to Sir John Herschel at Hawk- 
 hurst. From June I2th to Aug. nth I was travelling with 
 my wife on the Continent, being partly occupied with the 
 
154 GEORGE BIDDELL AIRY. 
 
 observation of the Total Eclipse of the Sun on July 7th. 
 The journey was in Switzerland and North Italy. In Decem- 
 ber I went to Cambridge and Ely, visiting Dr Peacock at the 
 latter place." . 
 
 From Feb. 23rd to 28th Airy was engaged on Observa- 
 tions of Tides at Southampton, Christchurch, Poole, and 
 Weymouth. During this expedition he wrote frequently (as 
 he always did) to his wife on the incidents of his journey, 
 and the following letters appear characteristic : 
 
 KING'S ARMS, CHRISTCHURCH, 
 OR XCHURCH, 
 
 1842, Feb. 24. 
 
 The lower of the above descriptions of my present place of 
 abode is the correct one, as I fearlessly assert on the authority of 
 divers direction-posts on the roads leading to it (by the bye this 
 supports my doctrine that x in Latin was not pronounced eks but 
 khi, because the latter is the first letter of Christ, for which x is here 
 traditionally put). Finding this morning that Yolland (who called 
 on me as soon as I had closed the letter to you) was perfectly 
 inclined to go on with the tide observations at Southampton, and 
 that his corporals of sappers were conducting them in the most 
 exemplary manner, I determined on starting at once. However we 
 first went to look at the New Docks (mud up to the knees) and truly 
 it is a very great work. There is to be enclosed a good number of 
 acres of water 22 feet deep: one dock locked in, the other a tidal 
 dock or basin with that depth at low water. They are surrounded 
 by brick walls eight feet thick at top, 10 or more at bottom ; and all 
 the parts that ever can be exposed are faced with granite. The 
 people reckon that this work when finished will attract a good deal 
 of the London commerce, and I should not be surprised at it. For 
 it is very much easier for ships to get into Southampton than into 
 London, and the railway carriage will make them almost one. A 
 very large steamer is lying in Southampton Water : the Oriental, 
 which goes to Alexandria. The Lady Mary Wood, a large steamer 
 for Lisbon and Gibraltar, was lying at the pier. The said pier is a 
 very pleasant place of promenade, the water and banks are so pretty, 
 and there is so much liveliness of ships about it. Well I started in 
 a gig, in a swashing rain, which continued off and on for a good 
 while. Of the 21 miles, I should think that 15 were across the New 
 
AT GREENWICH OBSERVATORY. 155 
 
 Forest. I do not much admire it. As for Norman William's destruc- 
 tion of houses and churches to make it hunting ground, that is utter 
 nonsense which never could have been written by anybody that ever 
 saw it: but as to hunting, except his horses wore something like 
 mud-pattens or snow-shoes, it is difficult to conceive it. Almost 
 the whole Forest is like a great sponge, water standing in every part. 
 In the part nearer to Xchurch forest trees, especially beeches, seem 
 to grow well. We stopped to bait at Lyndhurst, a small place high 
 up in the Forest : a good view, such as it is, from the churchyard. 
 The hills of the Isle of Wight occasionally in sight. On approaching 
 Xchurch the chalk cliffs of the west end of the Isle of Wight (leading 
 to the Needles) were partly visible ; and, as the sun was shining on 
 them, they fairly blazed. Xchurch is a small place with a magnifi- 
 cent-looking church (with lofty clerestory, double transept, &c., but 
 with much irregularity) which I propose to visit to-morrow. Also a 
 ruin which looks like an abbey, but the people call it a castle. There 
 is a good deal of low land about it, and the part between the town 
 and the sea reminded me a good deal of the estuary above Cardigan, 
 flat ill-looking bogs (generally islands) among the water. I walked 
 to the mouth of the river (more than two miles) passing a nice little 
 place called Sandford, with a hotel and a lot of lodgings for summer 
 sea-people. At the entrance of the river is a coastguard station, and 
 this I find is the place to which I must go in the morning to observe 
 the tide. I had some talk with the coastguard people, and they 
 assure me that the tide is really double as reported. As I came 
 away the great full moon was rising, and I could read in her unusu- 
 ally broad face (indicating her nearness to the earth) that there will 
 be a powerful tide. I came in and have had dinner and tea, and am 
 now going to bed, endeavouring to negociate for a breakfast at six 
 o'clock to-morrow morning. It is raining cats and dogs. 
 
 LUCE'S HOTEL, WEYMOUTH, 
 1842, Feb. 27. 
 
 This morning when I got up I found that it was blowing fresh 
 from S.W. and the sea was bursting over the wall of the eastern 
 extremity of the Esplanade very magnanimously. So (the swell not 
 being favourable for tide-observations) I gave them up and deter- 
 mined to go to see the surf on the Chesil Bank. I started with my 
 great-coat on, more for defence against the wind than against rain ; 
 
156 GEORGE BIDDELL AIRY. 
 
 but in a short time it began to rain, and just when I was approaching 
 the bridge which connects the mainland with the point where the 
 Chesil Bank ends at Portland (there being an arm of the sea behind 
 the Chesil Bank) it rained. and blew most dreadfully. However I 
 kept on and mounted the bank and ^descended a little way towards 
 the sea, and there was the surf in all its glory. I cannot give you 
 an idea of its majestic appearance. It was evidently very high, but 
 that was not the most striking part of it, for there was no such thing 
 as going within a considerable distance of it (the occasional outbreaks 
 of the water advancing so far) so that its magnitude could not be 
 well seen. My impression is that the height of the surf was from 10 
 to 20 feet. But the striking part was the clouds of solid spray which 
 formed immediately and which completely concealed all the other 
 operations of the water. They rose a good deal higher than the top 
 of the surf, so the state of things was this. A great swell is seen 
 coming, growing steeper and steeper ; then it all turns over and you 
 see a face just like the pictures of falls of Niagara; but in a little 
 more than one second this is totally lost and there is nothing before 
 you but an enormous impenetrable cloud of white spray. In about 
 another second there comes from the bottom of this cloud the foam- 
 ing current of water up the bank, and it returns grating the pebbles 
 together till their jar penetrates the very brain. I stood in the face 
 of the wind and rain watching this a good while, and should have 
 stood longer but that I was so miserably wet. It appeared to me 
 that the surf was higher farther along the bank, but the air was so 
 thickened by the rain and the spray that I could not tell. When I 
 returned the bad weather abated. I have now borrowed somebody 
 else's trowsers while mine are drying (having got little wet in other 
 parts, thanks to my great-coat, which successfully brought home a 
 hundredweight of water), and do not intend to stir out again except 
 perhaps to post this letter. 
 
 FLAMST-EED HOUSE, 
 
 1842, May 15. 
 
 Yesterday after posting the letter for you I went per steamboat 
 to Hungerford. I then found Mr Vignoles, and we trundled off 
 together, with another engineer named Smith, picking up Stratford 
 by the way, to Wormwood Scrubs. There was a party to see the 
 Atmospheric Railway in action : including (among others) Sir John 
 
AT GREENWICH OBSERVATORY. 157 
 
 Burgoyne, whom I met in Ireland several years ago, and Mr Pym, 
 the Engineer of the Dublin and Kingstown Railway, whom I have 
 seen several times, and who is very sanguine about this construction ; 
 and Mr Clegg, the proposer of the scheme (the man that invented 
 gas in its present arrangements), and Messrs Samuda, two Jews who 
 are the owners of the experiment now going on ; and Sir James 
 South ! With the latter hero and mechanician we did not come in 
 contact. Unfortunately the stationary engine (for working the air- 
 pump which draws the air out of the pipes and thus sucks the 
 carriages along) broke down during the experiment, but not till we 
 had seen the carriage have one right good run. And to be sure it is 
 very funny to see a carriage running all alone " as if the Devil drove 
 it " without any visible cause whatever. The mechanical arrange- 
 ments we were able to examine as well after the engine had broken 
 down as at any time. And they are very simple and apparently 
 very satisfactory, and there is no doubt of the mechanical practica- 
 bility of the thing even in places where locomotives can hardly be 
 used : whether it will pay or not is doubtful. I dare say that the 
 Commissioners' Report has taken a very good line of discrimination . 
 
 1843 
 
 " In March I wrote to Dr Wynter (Vice-Chancellor) at 
 Oxford, requesting permission to see Bradley's and Bliss's 
 manuscript Observations, with the view of taking a copy of 
 them. This was granted, and the books of Transits were 
 subsequently copied under Mr Breen's superintendence. 
 The following paragraph is extracted from the Report to the 
 Visitors : ' In the Report of last year, I stated that our reduc- 
 tions had dropped considerably in arrear. I have the satis- 
 faction now of stating that this arrear and very much more 
 have been completely recovered, and that the reductions are 
 now in as forward a state as at any time since my connection 
 with the Observatory.' In fact the observations of 1842 were 
 sent to press on Mar. 1st, 1843. About this year the Annual 
 Dinner at the Visitation began to be more important, princi- 
 pally under the management of Capt. W. H. Smyth, R.N. 
 In November I was enquiring about an 8-inch object-glass. 
 
158 GEORGE BIDDELL AIRY. 
 
 I had already in mind the furnishing of our meridional instru- 
 ments with greater optical powers. On July I4th the Admi- 
 ralty referred to me a Memorial of Mr J. G. Ulrich, a chrono- 
 meter maker, claiming a reward ftfr improvements in chrono- 
 meters. I took a great deal of trouble in the investigation of 
 this matter, by books, witnesses, Sec., and finally reported on 
 Nov. 4th that there was no ground for claim. In April I 
 received the first application of the Royal Exchange Com- 
 mittee, for assistance in the construction of the Clock : this 
 led to a great deal of correspondence, especially with Dent. 
 The Lunar Reductions were going on in full vigour. I had 
 much work in connection with the Cape Observatory : partly 
 about an equatoreal required for the Observatory, but chiefly 
 in getting Maclear's work through the press. In this year I 
 began to think seriously of determining the longitude of 
 Valencia in Ireland, as a most important basis for the scale 
 of longitude in these latitudes, by the transmission of chrono- 
 meters ; and in August I went to Valencia and examined the 
 localities. In September I submitted a plan to the Admi- 
 ralty, but it was deferred. The new Commission for restoring 
 the Standards was appointed on June 2Oth, I being Chair- 
 man. The work of collecting standards and arranging plans 
 was going on ; Mr Baily attending to Standards of Length, 
 and Prof. W. H. Miller to Standards of Weight. We held 
 two meetings. A small assistance was rendered to me by 
 Mr Charles May (of the firm of Ransomes and May), which 
 has contributed much to the good order of papers in the 
 Observatory. Mr Robert Ransome had remarked my method 
 of punching holes in the paper by a hand-punch, the places 
 of the holes being guided by holes in a piece of card, and 
 said that they could furnish me with something better. Ac- 
 cordingly, on Aug. 28th Mr May sent me the punching 
 machine, the prototype of all now used in the Observatory. 
 
 " On Sept. 25th was made my proposal for an Altazimuth 
 Instrument for making observations of the Moon's place 
 more frequently and through parts of her orbit where she 
 
AT GREENWICH OBSERVATORY, 159 
 
 could never be observed with meridional instruments ; the 
 most important addition to the Observatory since its founda- 
 tion. The Board of Visitors recommended it to the Admi- 
 ralty, and the Admiralty sanctioned the construction of the 
 instrument and the building to contain it." The following 
 passage is quoted from the Address of the Astronomer Royal 
 to the Board of Visitors at the Special Meeting of Nov. loth, 
 1843: "The most important object in the institution and 
 maintenance of the Royal Observatory has always been the 
 Observations of the Moon. In this term I include the deter- 
 mination of the places of fixed stars which are necessary for 
 ascertaining the instrumental errors applicable to the instru- 
 mental observations of the Moon. These, as regards the 
 objects of the institution, were merely auxiliaries : the history 
 of the circumstances which led the Government of the day to 
 supply the funds for the construction of the Observatory 
 shews that, but for the demands of accurate Lunar Determi- 
 nations as aids to navigation, the erection of a National 
 Observatory would never have been thought of. And this 
 object has been steadily kept in view when others (necessary 
 as fundamental auxiliaries) were passed by. Thus, during 
 the latter part of Bradley 's time, and Bliss's time (which two 
 periods are the least efficient in the modern history of the 
 Observatory), and during the latter part of Maskelyne's 
 presidency (when, for years together, there is scarcely a 
 single observation of the declination of a star), the Observa- 
 tions of the Moon were kept up with the utmost regularity. 
 And the effect of this regularity, as regards its peculiar object, 
 has been most honourable to the institution. The existing 
 Theories and Tables of the Moon are founded entirely upon 
 the Greenwich Observations ; the Observatory of Greenwich 
 has been looked to as that from which alone adequate obser- 
 vations can be expected, and from which they will not be 
 expected in vain : and it is not perhaps venturing too much 
 to predict that, unless some gross dereliction of duty by the 
 managers of the Observatory should occur, the Lunar Tables 
 
l6o GEORGE BIDDELL AIRY. 
 
 will always be founded on Greenwich Observations. With 
 this impression it has long been to me a matter of considera- 
 tion whether means should not be taken for rendering the 
 series of Observations of the Mbon more complete than it 
 can be made by the means at present recognized in our 
 observatories." In illustration of the foregoing remarks, the 
 original inscription still remaining on the outside of the wall 
 of the Octagon Room of the Observatory may be quoted. 
 It runs thus: ' Carolus II s Rex Optimus Astronomiae et 
 Nauticae Artis Patronus Maximus Speculam hanc in utri- 
 usque commodum fecit Anno D ni MDCLXXVI Regni sui 
 XXVIII curante lona Moore milite RTSG.' 
 
 " The Ashburton Treaty had been settled with the United 
 States, for the boundary between Canada and the State of 
 Maine, and one of its conditions was, that a straight line 
 about 65 miles in length should be drawn through dense 
 woods, connecting definite points. It soon appeared that 
 this could scarcely be done except by astronomical opera- 
 tions. Lord Canning, Under Secretary of the Foreign Office, 
 requested me to nominate two astronomers to undertake the 
 work. I strongly recommended that Military Officers should 
 carry out the work, and Capt. Robinson and Lieut. Pipon 
 were detached for this service. On Mar. ist they took 
 lodgings at Greenwich, and worked at the Observatory every 
 day and night through the month. My detailed astronomical 
 instructions to them were drawn out on Mar. 29th. I pre- 
 pared all the necessary skeleton forms, &c., and looked to 
 their scientific equipment in every way. The result will be 
 given in 1844. 
 
 " Of private history : In January I went to Dover with 
 my wife to see the blasting of a cliff there : we also visited 
 Sir J. Herschel at Hawkhurst. In April I was at Playford, 
 on a visit to Arthur Biddell. On Apr. 9th my daughter 
 Annot was born. From July 22nd to August 25th I was 
 travelling in the South of Ireland, chiefly to see Valencia 
 and consider the question of determining its longitude: 
 
AT GREENWICH OBSERVATORY. l6l 
 
 during this journey I visited Lord Rosse at Birr Castle, and 
 returned to Weymouth, where my family were staying at the 
 time. In October I visited Cambridge, and in December I 
 was again at Playford." 
 
 The journey to Cambridge (Oct. 24th to 27th) was ap- 
 parently in order to be present on the occasion of the Queen's 
 visit there on the 25th : the following letter relating to it 
 was written to his wife: 
 
 SEDGWICK'S ROOMS, 
 TRINITY COLLEGE, CAMBRIDGE. 
 
 1843, Oct. 26, Thursday. 
 
 I have this morning received your letter : I had no time to write 
 yesterday. There are more things to tell of than I can possibly 
 remember. The Dean of Ely yesterday was in a most ludicrous 
 state of misery because his servant had sent his portmanteau (con- 
 taining his scarlet academicals as well as everything else) to London, 
 and it went to Watford before it was recovered : but he got it in time 
 to shew himself to-day. Yesterday morning I came early to break- 
 fast with Sedgwick. Then I walked about the streets to look at the 
 flags. Cambridge never had such an appearance before. In looking 
 along Trinity Street or Trumpington Street there were arches and 
 flags as close as they could stand, and a cord stretched from King's 
 Entrance to Mr Deck's or the next house with flags on all its length : 
 a flag on St Mary's, and a huge royal standard ready to hoist on 
 Trinity Gateway : laurels without end. I applied at the Registrar's 
 office for a ticket which was to admit me to Trinity Court, the Senate 
 House, &c., and received from Peacock one for King's Chapel. 
 Then there was an infinity of standing about, and very much I was 
 fatigued, till I got some luncheon at Blakesley's rooms at i o'clock. 
 This was necessary because there was to be no dinner in hall on 
 account of the Address presentation. The Queen was expected at 2, 
 and arrived about 10 minutes after 2. When she drove up to Trinity 
 Gate, the Vice-Chancellor, masters, and beadles went to meet her, 
 and the beadles laid down their staves, which she desired them to 
 take again. Then she came towards the Lodge as far as the Sun- 
 dial, where Whewell as master took the college keys (a bundle of 
 rusty keys tied together by a particularly greasy strap) from the 
 bursar Martin, and handed them to the Queen, who returned them. 
 Then she drove round by the turret-corner of the court to the Lodge 
 
 A. B, II 
 
162 GEORGE BIDDELL AIRY. 
 
 door. Almost every member of the University was in the court, and 
 there was a great hurraing except when the ceremonies were going 
 forward. Presently the Queen appeared at a window and bowed, 
 and was loudly cheered. .Then notice was given that the Queen and 
 Prince would receive the Addresses ;"pf the University in Trinity hall, 
 and a procession was formed, in which I had a good place, as I 
 claimed rank with the Professors. A throne and canopy were 
 erected at the top of the hall, but the Queen did riot sit, which was 
 her own determination, because if she had sat it would have been 
 proper that everybody should back out before presenting the Address 
 to the Prince : which operation would have suffocated at least 100 
 people. The Queen wore a blue gown and a brown shawl with an 
 immense quantity of gold embroidery, and a bonnet. Then it was 
 known that the Queen was going to service at King's Chapel at half 
 past three : so everybody went there. I saw the Queen walk up the 
 antechapel and she looked at nothing but the roof. I was not able 
 to see her in chapel or to see the throne erected for her with its back 
 to the Table, which has given great offence to many people. (I 
 should have said that before the Queen came I called on Dr Havi- 
 land, also on Scholefield, also on the Master of Christ's.) After this 
 she returned to Trinity, and took into her head to look at the chapel. 
 The cloth laid on the pavement was not long enough and the under- 
 graduates laid down their gowns. Several of the undergraduate 
 noblemen carried candles to illuminate Newton's statue. After this 
 the Prince went by torchlight to the library. Then I suppose came 
 dinner, and then it was made known that at half-past nine the Queen 
 would receive some Members of the University. So I rigged myself 
 up and went to the leve'e at the Lodge and was presented in my turn 
 by the Vice-Chancellor as " Ex-Professor Airy, your Majesty's As- 
 tronomer Royal." The Queen and the Prince stood together, and a 
 bow was made to and received from each. The Prince recognised 
 me and said " I am glad to see you," or something like that. Next 
 to him stood Goulburn, and next Lord Lyndhurst, who to my great 
 surprise spoke very civilly to me (as I will tell you afterwards). The 
 Queen had her head bare and a sort of French white gown and 
 looked very well. She had the ribbon of the Garter on her breast ; 
 but like a ninny I forgot to look whether she had the Garter upon 
 her arm. The Prince wore his Garter. I went to bed dead tired and 
 got up with a headache. About the degree to the Prince and the 
 other movements I will write again. 
 
AT GREENWICH OBSERVATORY. 163 
 
 Here is a note from Cubitt relating to the blasting of the 
 Round Down Cliff at Dover referred to above : 
 
 GREAT GEORGE STREET, 
 
 Jan. 2oth, 1843. 
 MY DEAR SIR, 
 
 Thursday next the 26th at 12 is the time fixed for the 
 attempt to blow out the foot of the " Round Down " Cliff near 
 Dover. 
 
 The Galvanic apparatus has been repeatedly tried in place that 
 is by exploding cartridges in the very chambers of the rock prepared 
 for the powder with the batteries at 1200 feet distance they are in 
 full form and act admirably so that I see but little fear of failure on 
 that head. 
 
 They have been rehearsing the explosions on the plan I most 
 strongly recommended, that is to fire each chamber by an indepen- 
 dent battery and circuit and to discharge the three batteries simul- 
 taneously by signal or word of command which answers well and " no 
 mistake." 
 
 I shall write to Sir John Herschel to-day, and remain 
 
 My dear Sir, 
 
 Very truly yours, 
 
 W. CUBITT. 
 G. B. Airy, Esq. 
 
 The following extracts are from letters to his wife 
 written in Ireland when on his journey to consider the 
 determination of the longitude of Valencia. 
 
 SKIBBEREEN, 
 
 1843, July 28. 
 
 By the bye, to shew the quiet of Ireland now, I saw in a news- 
 paper at Cork this account. At some place through which a repeal- 
 association was to pass (I forget its name) the repealers of the place 
 set up a triumphal arch. The police pulled it down, and were pelted 
 by the repealers, and one of the policemen was much bruised. 
 O'Connell has denounced this place as a disgrace to the cause of 
 repeal, and has moved in the full meeting that the inhabitants of this 
 place be struck off the repeal list, with no exception but that of the 
 
 II 2 
 
164 GEORGE BIDDELL AIRY. 
 
 parish priest who was proved to be absent. And O'Connell declares 
 that he will not pass through this place. Now for my journey. It 
 is a sort of half-mountain country all the way, with some bogs to 
 refresh my eyes. . 
 
 VALENCIA HOTEL, 
 
 1843, August 6. 
 
 It seems that my coming here has caused infinite alarm. The 
 common people do not know what to conjecture, but have some 
 notion that the " sappers and miners " are to build a bridge to admit 
 the charge of cavalry into the island. An attendant of Mrs Fitz- 
 gerald expressed how strange it was that a man looking so mild and 
 gentle could meditate such things " but never fear, Maam, those that 
 look so mild are always the worst " : then she narrated how that her 
 husband was building some stables, but that she was demanding of 
 him " Pat, you broth of a boy, what is the use of your building stables 
 when these people are coming to destroy everything." I suspect that 
 the people who saw me walking up through the storm yesterday must 
 have thought me the prince of the powers of the air at least. 
 
 HIBERNIAN HOTEL, TRALEE, 
 
 1843, August 7. 
 
 I sailed from Valencia to Cahersiveen town in a sail-boat up the 
 water (not crossing at the ferry). I had accommodated my time to 
 the wish of the boatman, who desired to be there in time for prayers : 
 so that I had a long waiting at Cahersiveen for the mail car. In 
 walking through the little town, I passed the chapel (a convent 
 chapel) to which the people were going : and really the scene was 
 very curious. The chapel appeared to be overflowing full, and the 
 court in front of it was full of people, some sitting on the ground, 
 some kneeling, and some prostrate. There were also people in the 
 street, kneeling with their faces towards the gate pillars, &c. It 
 seemed to me that the priest and the chapel were of less use here 
 than even in the continental churches, and I do not see why both 
 parties should not have stopped at home. When the chapel broke 
 up, it seemed as if the streets were crammed with people. The turn- 
 out that even a small village in Ireland produces is perfectly amazing. 
 
AT GREENWICH OBSERVATORY. 165 
 
 1844 
 
 "In the course of 1843 I had put in hand the engraving 
 of the drawings of the Northumberland Telescope at Cam- 
 bridge Observatory, and wrote the description for letter- 
 press. In the course of 1844 the work was completed, and 
 the books were bound and distributed. 
 
 " The building to receive the Altazimuth Instrument was 
 erected in the course of the year; during the construction a 
 foreman fell into the foundation pit and broke his leg, of 
 which accident he died. This is the only accident that I 
 have known at the Observatory. The Electrometer Mast 
 and sliding frame were erected near the Magnetic Observa- 
 tory. The six-year Catalogue of 1439 stars was finished ; 
 this work had been in progress during the last few years. In 
 May I went to Woolwich to correct the compasses of the 
 ' Dover/ a small iron steamer carrying mails between Dover 
 and Ostend : this I believe was the first iron ship possessed 
 by the Admiralty. The Lunar Reductions were making 
 good progress; 16 computers were employed upon them. 
 I made application for printing them and the required sum 
 (;iooo) was granted by the Treasury. In this year com- 
 menced that remarkable movement which led to the dis- 
 covery of Neptune. On Feb. I3th Prof. Challis introduced 
 Mr Adams to me by letter. On Feb. i$th I sent my ob- 
 served places of Uranus, which were wanted. On June 
 1 9th I also sent places to Mr E. Bouvard. As regards 
 the National Standards, Mr Baily (who undertook the com- 
 parisons relating to standards of length) died soon, and 
 Mr Sheepshanks then undertook the work. I attended the 
 meeting of the British Association held at York (principally 
 in compliment to the President, Dr Peacock), and gave an 
 oral account of my work on Irish Tides. At the Oxford 
 Commemoration in June, the honorary degree of D.C.L. was 
 conferred on M. Struve and on me, and then a demand was 
 
1 66 GEORGE BIDDELL AIRY. 
 
 made on each of us for 6. 6s. for fees. We were much 
 disgusted and refused to pay it, and 1 wrote angrily to 
 Dr Wynter, the Vice-Chancellor. The fees were ultimately 
 paid out of the University Chest:- 
 
 " In this year the longitude of Altona was determined -by 
 M. Struve for the Russian Government. For this purpose 
 it was essential that facilities should be given for landing 
 chronometers at Greenwich. But the consent of the custom- 
 house authorities had first to be obtained, and this required 
 a good deal of negotiation. Ultimately the determination 
 was completed in the most satisfactory manner. The chro- 
 nometers, forty-two in number, crossed the German Sea six- 
 teen times. The transit observers were twice interchanged, 
 in order to eliminate not only their Personal Equation, but 
 also the gradual change of Personal Equation. On Sept. 
 3Oth Otto Struve formally wrote his thanks for assistance 
 rendered. 
 
 "For the determination of the longitude of Valencia, which 
 was carried out in this year, various methods were discussed, 
 but the plan of sending chronometers by mail conveyance 
 was finally approved. From London to Liverpool the chro- 
 nometers were conveyed by the railways, from Liverpool to 
 Kingstown by steamer, from Dublin to Tralee by the Mail 
 Coaches, from Tralee to Cahersiveen by car, from Cahersi- 
 veen to Knightstown by boat, and from Knightstown to the 
 station on the hill the box was carried like a sedan-chair. 
 There were numerous other arrangements, and all succeeded 
 perfectly without a failure of any kind. Thirty pocket chro- 
 nometers traversed the line between Greenwich and Kings- 
 town about twenty-two times, and that between Kingstown 
 and Valencia twenty times. The chronometrical longitudes 
 of Liverpool Observatory, Kingstown Station, and Valencia 
 Station are I2 m ox>5 s , 24 3i'i7 s , 41 23-25*; the geodetic 
 longitudes, computed from elements which I published 
 long ago in the Encyclopaedia Metropolitana, are I2 m O'34 S , 
 24 m 3 1 '47 s , 4i m 23'o6 s . It appears from this that the ele- 
 
AT GREENWICH OBSERVATORY. 167 
 
 ments to which I have alluded represent the form of the 
 Earth here as nearly as is possible. On the whole, I think 
 it probable that this is the best arc of parallel that has ever 
 been measured. 
 
 "With regard to the Maine Boundary: on May 7th 
 Col. Estcourt, the British Commissioner, wrote to me de- 
 scribing the perfect success of following out my plan : the 
 line of 64 miles was cut by directions laid out at the two 
 ends, and the cuttings met within 341 feet. The country 
 through which this line was to pass is described as sur- 
 passing in its difficulties the conception of any European. 
 It consists of impervious forests, steep ravines, and dismal 
 swamps. A survey for the line was impossible, and a tenta- 
 tive process would have broken the spirit of the best men. 
 I therefore arranged a plan of operations founded on a 
 determination of the absolute latitudes and the difference 
 of longitudes of the two extremities. The difference of 
 longitudes was determined by the transfer of chronometers 
 by the very circuitous route from one extremity to the 
 other; and it was necessary to divide the whole arc into 
 four parts, and to add a small part by measure and bearing. 
 When this was finished, the azimuths of the line for the two 
 ends were computed, and marks were laid off for starting 
 with the line from both ends. One party, after cutting more 
 than forty-two miles through the woods, were agreeably sur- 
 prised, on the brow of a hill, at seeing directly before them 
 a gap in the woods on the next line of hill ; it opened 
 gradually, and proved to be the line of the opposite party. 
 On continuing the lines till they passed abreast of each 
 other, their distance was found to be 341 feet. To form 
 an estimate of the magnitude of this error, it is to be 
 observed that it implies an error of only a quarter of a 
 second of time in the difference of longitudes ; and that it 
 is only one-third (or nearly so) of the error which would 
 have been committed if the spheroidal form of the Earth 
 had been neglected. I must point out the extraordinary 
 
1 68 GEORGE BIDDELL AIRY. 
 
 merit of the officers who effected this operation. Transits 
 were observed and chronometers were interchanged when 
 the temperature was lower than 19 below zero : and when 
 the native assistants, though paid highly, deserted on ac- 
 count of the severity of the weather, the British officers still 
 continued the observations upon whose delicacy everything 
 depended. 
 
 "Of private history: From July 3rd to Aug. I3th I was in 
 Ireland with my wife. This was partly a business journey 
 in connection with the determination of the longitude of 
 Valencia. On Jan. 4th I asked Lord Lyndhurst (Lord 
 Chancellor) to present my brother to the living of Hel- 
 mingham, which he declined to do: but on Dec. I2th he 
 offered Binbrooke, which I accepted for my brother." 
 
 1845 
 
 " A map of the Buildings and Grounds of the Observatory 
 was commenced in 1844, and was still in progress. On 
 Mar. i gth I was employed on a matter which had for some 
 time occupied my thoughts, viz., the re-arrangement of 
 current manuscripts. I had prepared a sloping box (still in 
 use) to hold 24 portfolios : and at this time I arranged papers 
 A, and went on with B, C, &c. Very little change has been 
 made in these. In reference to the time given to the weekly 
 report on Meteorology to the Registrar General, the Report 
 to the Board of Visitors contains the following paragraph : 
 ' The devotion of some of my assistants' time and labour to 
 the preparation of the Meteorological Report attached to the 
 weekly report of the Registrar General, is, in my opinion, 
 justified by the bearing of the meteorological facts upon the 
 medical facts, and by the attention which I understand that 
 Report to have excited.' On Dec. I3th the sleep of Astronomy 
 was broken by the announcement that a new planet, Astraea, 
 was discovered by Mr Hencke. I immediately circulated 
 notices. But in this year began a more remarkable planetary 
 
AT GREENWICH OBSERVATORY. 169 
 
 discussion. On Sept. 22nd Challis wrote to me to say that 
 Mr Adams would leave with me his results on the explanation 
 of the irregularities of Uranus by the action of an exterior 
 planet. In October Adams called, in my absence. On 
 Nov. 5th I wrote to him, enquiring whether his theory ex- 
 plained the irregularity of radius-vector (as well as that of 
 longitude). I waited for an answer, but received none. 
 (See the Papers printed in the Royal Astronomical Society's 
 Memoirs and Monthly Notices). In the Royal Society, the 
 Royal Medal was awarded to me for my Paper on the Irish 
 Tides. In the Royal Astronomical Society I was President ; 
 and, with a speech, delivered the Medal to Capt. Smyth for 
 the Bedford Catalogue of Double Stars. On Jan. 2ist I was 
 appointed (with Schumacher) one of the Referees for the King 
 of Denmark's Comet Medal : I have the King's Warrant under 
 his sign manual. The Tidal Harbour Commission com- 
 menced on Apr. 5th: on July 2 1st my Report on Wexford 
 Harbour (in which I think I introduced important principles) 
 was communicated. One Report was made this year to the 
 Government. In the matter of Saw Mills (which had begun 
 in 1842), I had prepared a second set of plans in 1844, and in 
 this year Mr Nasmyth made a very favourable report on my 
 plan. A machinist of the Chatham Dock Yard, Sylvester, 
 was set to work (but not under my immediate command) to 
 make a model : and this produced so much delay as ulti- 
 mately to ruin the design. On Jan. 1st I was engaged on my 
 Paper ' On the flexure of a uniform bar, supported by equal 
 pressures at equidistant points.' " (This was probably in con- 
 nection with the support of Standards of Length, for the 
 Commission. Ed.). In June I attended the Meeting of the 
 British Association at Cambridge, and on the 2Oth I gave a 
 Lecture on Magnetism in the Senate House. The following 
 quotation relating to this Lecture is taken from a letter by 
 Whewell to his wife (see Life of William Whewell by Mrs 
 Stair Douglas) : " I did not go to the Senate House yester- 
 day evening. Airy was the performer, and appears to have 
 
L7O GEORGE BIDDELL AIRY. 
 
 outdone himself in his art of giving clearness and simplicity 
 to the hardest and most complex subjects. He kept the 
 attention of his audience quite enchained for above two 
 hours, talking about terrestrial magnetism." On Nov. 29th 
 I gave evidence before a Committee of the House of Com- 
 mons on Dover Harbour Pier. 
 
 " With respect to the Magnetical and Meteorological Estab- 
 lishment, the transactions in this year were most important. 
 It had been understood that the Government establishments 
 had been sanctioned twice for three-year periods, of which the 
 second would expire at the end of 1845 : ano ^ it was a ques- 
 tion with the scientific public whether they should be con- 
 tinued. My own opinion was in favour of stopping the 
 observations and carefully discussing them. And I am 
 convinced that this would have been best, except for the 
 subsequent introduction of self-registering systems, in which 
 I had so large a share. There was much discussion and cor- 
 respondence, and on June /th the Board of Visitors resolved 
 that ' In the opinion of the Visitors it is of the utmost im- 
 portance that these observations should continue to be made 
 on the most extensive scale which the interests of those 
 sciences may require.' The meeting of the British Associa- 
 tion was held at Cambridge in June : and one of the most 
 important matters there was the Congress of Magnetic 
 Philosophers, many of them foreigners. It was resolved 
 that the Magnetic Observatory at Greenwich be continued 
 permanently. At this meeting I proposed a resolution which 
 has proved to be exceedingly important. I had remarked 
 the distress which the continuous two-hourly observations 
 through the night produced to my Assistants, and determined 
 if possible to remove it. I therefore proposed * That it is 
 highly desirable to encourage by specific pecuniary reward 
 the improvement of self-recording rnagnetical and meteoro- 
 logical apparatus : and that the President of the British 
 Association and the President of the Royal Society be 
 requested to solicit the favourable consideration of Her 
 
AT GREENWICH OBSERVATORY. 171 
 
 Majesty's Government to this subject/ which was adopted. 
 In October the Admiralty expressed their willingness to 
 grant a reward up to 500. Mr Charles Brooke had written 
 to me proposing a plan on Sept. 23rd, and he sent me his 
 first register on Nov. 24th. On Nov. 1st the Treasury in- 
 formed the Admiralty that the Magnetic Observatories will 
 be continued for a further period. 
 
 " The Railway Gauge Commission in this year was an 
 important employment. The Railways, which had begun 
 with the Manchester and Liverpool Railway (followed by the 
 London and Birmingham) had advanced over the country 
 with some variation in their breadth of gauge. The gauge of 
 the Colchester Railway had been altered to suit that of the 
 Cambridge Railway. And finally there remained but two 
 gauges : the broad gauge (principally in the system allied 
 with the Great Western Railway); and the narrow gauge 
 (through the rest of England). These came in contact at 
 Gloucester, and were likely to come in contact at many other 
 points to the enormous inconvenience of the public. The 
 Government determined to interfere, beginning with a Com- 
 mission. On July 3rd Mr Laing (then on the Board of 
 Trade) rode to Greenwich, bearing a letter of introduction 
 from Sir John Lefevre and a request from Lord Dalhousie 
 (President of the Board of Trade) that I would act as second 
 of a Royal Commission (Col. Sir Frederick Smith, Airy, Prof. 
 Barlow). I assented to this : and very soon began a vigorous 
 course of business. On July 23rd and 24th I went with Prof. 
 Barlow and our Secretary to Bristol, Gloucester, and Birming- 
 ham : on Dec. I7th I went on railway experiments to Didcot : 
 and on Dec. 2pth to Jan. 2nd I went to York, with Prof. 
 Barlow and George Arthur Biddell, for railway experiments. 
 On Nov. 2 ist I finished a draft Report of the Railway Gauge 
 Commission, which served in great measure as a basis for that 
 adopted next year. 
 
 " Of private history : I wrote to Lord Lyndhurst on Feb. 
 2Oth, requesting an exchange of the living to which he had 
 
1/2 GEORGE BIDDELL AIRY. 
 
 presented my brother in Dec. 1844 for that of Swineshead : to 
 which he consented. On Jan. 2Qth I went with my wife on a 
 visit to my uncle George Biddell, at Bradfield St George, near 
 Bury. On June Qth I went into th& mining district of Cornwall 
 with George Arthur Biddell. From Aug. 25th to Sept. 26th 
 I was travelling in France with my sister and my wife's sister, 
 Georgiana Smith. I was well introduced, arid the journey 
 was interesting. On Oct. 2Qth my son Osmund was born. 
 Mr F. Baily bequeathed to me 500, which realized 450." 
 
 Here are some extracts from letters written to his wife 
 relating to the visit to the Cornish mines, &c. 
 
 PEARCE'S HOTEL, FALMOUTH, 
 1845, June I2//&, Thursday. 
 
 Then we walked to the United Mines in Gwennap. The day 
 was very fine and now it was perfectly broiling : and the hills here 
 are long and steep. At the United Mines we found the Captain, 
 and he invited us to join in a rough dinner, to which he and the 
 other captains were going to sit down. Then we examined one of 
 the great pumping engines, which is considered the best in the 
 country: and some other engines. Between 3 and 4 there was to 
 be a setting out of some work to the men by a sort of Dutch Auction 
 (the usual way of setting out the work here) : some refuse ores were 
 to be broken up and made marketable, and the subject of competi- 
 tion was, for how little in the pound on the gross produce the men 
 would work them up. While we were here a man was brought up 
 who was hurt in blasting : a piece of rock had fallen on him. At this 
 mine besides the ladder ways, they have buckets sliding in guides by 
 which the men are brought up: and they are just preparing for work 
 another apparatus which they say is tried successfully at another 
 mine (Tresavean) : there are two wooden rods A and B reaching from 
 the top to the bottom, moved by cranks from the same wheel, so that 
 one goes up when the other goes down, and vice versa: each of 
 these rods has small stages, at such a distance that when the rod A 
 is down and the rod B is up, the first stage of A is level with the 
 first stage of B\ but when the rod A is up and the rod B is down, 
 the second stage of A is level with the first stage of B : so a man 
 who wants to descend steps on the first stage of A and waits till it 
 goes down: then he steps sideways on the first stage of B and waits 
 
AT GREENWICH OBSERVATORY. 173 
 
 till it goes down : then he steps sideways to the second stage of A 
 and waits till it goes down, and so on : or if a man is coming up he 
 does just the same. While we were here Mr R. Taylor came. We 
 walked home (a long step, perhaps seven miles) in a very hot sun. 
 Went to tea to Mr Alfred Fox, who has a house in a beautiful 
 position looking to the outside of Falmouth Harbour. 
 
 PENZANCE, 
 1845, June 14, Satitrday. 
 
 Yesterday morning we breakfasted early at Falmouth, and before 
 9 started towards Gwennap. I had ascertained on Thursday that 
 John Williams (the senior of a very wealthy and influential family in 
 this country) was probably returned from London. So we drove first 
 to his house Burntcoose or Barncoose, and found him and his wife 
 at home. (They are Quakers, the rest of the family are not.) Sedg- 
 wick, and Whewell, and I, or some of our party including me, had slept 
 once at their house. They received George and me most cordially, and 
 pressed us to come and dine with them after our visit to Tresavean 
 mine, of which intention I spoke in my last letter: so I named 
 4 o'clock as hour for dinner. After a little stay we drove to 
 Tresavean, where I found the Captain of the mine prepared to send 
 an Underground Captain and a Pit-man to descend with us. So we 
 changed our clothes and descended by the ladders in the pumpshaft. 
 Pretty work to descend with the huge pump-rods (garnished with 
 large iron bolts) working violently, making strokes of 12 feet, close to 
 our elbows; and with a nearly bottomless pit at the foot of every 
 ladder, where we had to turn round the foot of the ladder walking 
 on only a narrow board. However we got down to the bottom of 
 the mine with great safety and credit, seeing all the mighty 
 machinery on the way, to a greater depth than I ever reached 
 before, namely 1900 feet. From the bottom of the pump we went 
 aside a short distance into the lowest workings where two men 
 nearly naked were driving a level towards the lode or vein of ore. 
 Here I felt a most intolerable heat : and upon moving to get out of 
 the place, I had a dreadful feeling of feebleness and fainting, such 
 as I never had in my life before. The men urged me to climb the 
 ladders to a level where the air was better, but they might as well 
 have urged me to lift up the rock. I could do nothing but sit down 
 and lean fainting against the rocks. This arose entirely from the 
 
174 GEORGE BIDDELL AIRY. 
 
 badness of the air. After a time I felt a trifle better, and then I 
 climbed one short ladder, and sat down very faint again. When I 
 recovered, two men tied a rope round me, and went up the ladder 
 before me, supporting a .part of my weight, and in this way I 
 ascended four or five ladders (with lorig rests between) till we came 
 to a level, 260 fathoms below the adit or nearly 300 fathoms below 
 the surface, where there was a tolerable current of pretty good air. 
 Here I speedily recovered, though I was a little weak for a short 
 time afterwards. George also felt the bad air a good deal, but not 
 so much as I. He descended to some workings equally low in 
 another place (towards which the party that I spoke of were directing 
 their works), but said that the air there was by no means so bad. 
 We all met at the bottom of the man-engine 260 fathoms below the 
 adit. We sat still a little while, and I acquired sufficient strength 
 and nerve, so that I did not feel the slightest alarm in the operation 
 of ascending by the man-engine. This is the funniest operation that I 
 ever saw : it is the only absolute novelty that I have seen since I was 
 in the country before : it has been introduced 2 J years in Tresavean, 
 and one day in the United Mines. In my last letter I described 
 the principle. In the actual use there is no other motion to be made 
 by the person who is ascending or descending than that of stepping 
 sideways each time (there being proper hand-holds) with no exertion 
 at all, except that of stepping exactly at the proper instant : and not 
 the shadow of unpleasant feeling in the motion. Any woman may 
 go with the most perfect comfort, if she will but attend to the rules 
 of stepping, and forget that there is an open pit down to the very 
 bottom of the mine. In this way we were pumped up to the surface, 
 and came up as cool as cucumbers, instead of being drenched with 
 perspiration. In my description in last letter I forgot to mention 
 that between the stages on the moving rods which I have there 
 described there are intermediate stages on the moving rods (for 
 which there is ample room, inasmuch as the interval between the 
 stages on each rod used by one person is 24 feet), and these inter- 
 mediate stages are used by persons descending-, so that there are 
 persons ascending and persons descending at the same time, who never 
 interfere with each other and never step on the same stages, but merely 
 see each other passing on the other rods. It is a most valuable in- 
 vention. We then changed our clothes and washed, and drove to 
 Barncoose, arriving in good time for the dinner. I found myself much 
 restored by some superb Sauterne with water. When we were pro- 
 posing to go on to Camborne, Mr and Mrs Williams pressed us so 
 
AT GREENWICH OBSERVATORY. 175 
 
 affectionately to stop that we at length decided on stopping for the 
 night, only bargaining for an early breakfast this morning. This 
 morning after breakfast, we started for Redruth and Camborne. The 
 population between them has increased immensely since I was here 
 before. &c. &c. 
 
 Here is a letter written to his wife while he was engaged 
 on the business of the Railway Gauge Commission. It con- 
 tains reminiscences of some people who made a great figure 
 in the railway world at that time, and was preceded by a 
 letter which was playfully addressed " From the Palace of 
 King Hudson, York." 
 
 GEORGE INN, YORK, 
 
 1845, Dec. 30. 
 
 I wrote yesterday from Mr Hudson's in time for the late post, 
 and hope that my letter might be posted by the servant to whom it 
 was given. Our affairs yesterday were simple : we reached Euston 
 Station properly, found Watson there, found a carriage reserved for 
 us, eat pork-pie at Wolverton (not so good as formerly), dined at 
 Derby, and arrived in York at 5.20. On the way Watson informed 
 me that the Government have awarded us .500 each. Sir F. Smith 
 had talked over the matter with us, and I laid it down as a principle 
 that we considered the business as an important one and one of very 
 great responsibility, and that we wished either that the Government 
 should treat us handsomely or should consider us as servants of the 
 State acting gratuitously, to which they assented. I think the 
 Government have done very well. Mr Hudson, as I have said, met 
 us on the platform and pressed us to dine with him (though I had 
 dined twice). Then we found the rival parties quarrelling, and had 
 to arrange between them. This prevented me from writing for the 
 early post. (I forgot to mention that Saunders, the Great Western 
 Secretary, rode with us all the way). At Hudson's we had really a 
 very pleasant dinner: I sat between Vernon Harcourt and Mrs 
 Malcolm (his sister Georgiana) and near to Mr Hudson. This morn- 
 ing we were prepared at 9 at the Station for some runs. Brunei and 
 other people had arrived in the night. And we have been to 
 Darlington and back, with a large party in our experimental train. 
 George Arthur Biddell rode on the engine as representing me. But 
 the side wind was so dreadfully heavy that, as regards the wants of the 
 
176 GEORGE BIDDELL AIRY. 
 
 case, this day is quite thrown away. We have since been to lunch 
 with Vernon Harcourt (Mrs Harcourt not at home) and then went 
 with him to look at the Cathedral. The Chapter-house, which was a 
 little injured, has been pretty well restored : all other things in good 
 order. The Cathedral looks smaller and lower than French 
 cathedrals. Now that we have come in, the Lord Mayor of York 
 has just called to invite us to dinner to-morrow. I propose to 
 George Arthur Biddell that he go to Newcastle this evening, in order 
 to see glass works and other things there to-morrow, and to return 
 when he can. 
 
 I think that I can persuade Barlow to stop to see the experiments 
 out, and if so I shall endeavour to return as soon as possible. The 
 earliest day would be the day after to-morrow. 
 
 The following extract is from a letter written to Mr 
 Murray for insertion in his Handbook of France, relating to 
 the Breakwater at Cherbourg, which Airy had visited during 
 his journey in France in the autumn of this year. 
 
 ROYAL OBSERVATORY, GREENWICH, 
 
 1845, Oct. %th. 
 
 My opinion on the construction I need not say ought not to be 
 quoted : but you are quite welcome to found any general statement 
 on it ; or perhaps it may guide you in further enquiries. To make it 
 clear, I must speak rather generally upon the subject. There are 
 three ways in which a breakwater may be constructed. i. By 
 building a strong wall with perpendicular face from the bottom of 
 the sea. 2. By making a bank with nothing but slopes towards the 
 sea. 3. By making a sloping bank to a certain height and then 
 building a perpendicular wall upon it. Now if the ist of these con- 
 structions could be arranged, I have no doubt that it would be the 
 best of all, because a sea does not break against a perpendicular face, 
 but recoils in an unbroken swell, merely making a slow quiet push at 
 the wall, and not making a violent impact. But practically it is nearly 
 impossible. The 2nd construction makes the sea to break tremen- 
 dously, but if the sloping surface be made of square stone put together 
 with reasonable care there is not the smallest tendency to unseat 
 these stones. This is the principle of construction of Plymouth 
 Breakwater. In the 3rd construction, the slope makes the sea 
 to break tremendously, and then it strikes the perpendicular face 
 
AT GREENWICH OBSERVATORY. 177 
 
 with the force of a battering ram : and therefore in my opinion this 
 is the worst construction of all. A few face-stones may easily be 
 dislodged, and then the sea entering with this enormous force will 
 speedily destroy the whole. This is the form of the Cherbourg 
 Digue. 
 
 From this you will gather that I have a full belief that Plymouth 
 Breakwater will last very long, and that the Digue of Cherbourg, at 
 least its upper wall, will not last long. The great bank will last a 
 good while, gradually suffering degradation, but still protecting the 
 Road pretty well. 
 
 I was assured by the officers residing on the Digue that the sea 
 which on breaking is thrown vertically upwards and then falls down 
 upon the pavement does sometimes push the stones about which are 
 lying there and which weigh three or four tons. 
 
 I saw some preparations for the foundations of the fort at the 
 eastern extremity of the Digue. One artificial stone of concrete 
 measured 12''$" x 6''7" x $''?", and was estimated to weigh 25000 
 kilogrammes. 
 
 A. B. 12 
 
CHAPTER VI. 
 AT GREENWICH OBSERVATORY 1846 TO 1856. 
 
 1846 
 
 " ON Nov. /th I proposed a change in the form of 
 Estimates for the Observatory. The original astronomical 
 part was provided by the Admiralty, and the new mag- 
 netical and meteorological part was provided by the 
 Treasury : and the whole Estimates and Accounts of the 
 Observatory never appeared in one public paper. I pro- 
 posed that the whole should be placed on the Navy Esti- 
 mates, but the Admiralty refused. I repeated this in sub- 
 sequent years, with no success. Meantime I always sent to 
 the Admiralty a duplicate of my Treasury Estimate with the 
 proper Admiralty Estimate. Stephenson's Railway through 
 the lower part of the Park, in tunnel about 850 feet from the 
 Observatory, was again brought forward. On Feb. 2Oth it 
 was put before me by the Government, and on March 9th I 
 made experiments at Kensal Green, specially on the effect of 
 a tunnel : which I found to be considerable in suppressing the 
 tremors. On May 6th I made my Report, generally favour- 
 able, supposing the railway to be in tunnel. On May I3th I, 
 with Mr Stephenson, had an interview at the Admiralty with 
 Lord Ellenborough and Sir George Cockburn. The Earl 
 appeared willing to relax in his scruples about allowing a 
 railway through the Park, when Sir George Cockburn made a 
 most solemn protest against it, on the ground of danger to an 
 institution of such importance as the Observatory. I have no 
 doubt that this protest of Sir George Cockburn's really deter- 
 
AT GREENWICH OBSERVATORY 1846 TO 1856. 179 
 
 mined the Government. On June zoth I was informed that 
 the Government refused their consent. After this the South 
 Eastern Railway Company adopted the line through Tranquil 
 Vale. In consequence of the defective state of Paramatta 
 Observatory I had written to Sir Robert Peel on April i6th 
 raising the question of a General Superintending Board for 
 Colonial Observatories : and on June 27th I saw Mr Gladstone 
 at the Colonial Office to enquire about the possibility of estab- 
 lishing local Boards. On June 2pth a general plan was 
 settled, but it never came to anything. Forty volumes of the 
 Observatory MSS. were bound an important beginning. 
 Deep-sunk thermometers were prepared by Prof. Forbes. 
 On June 22nd Sir Robert Inglis procured an Order of the 
 House of Commons for printing a paper of Sir James South's, 
 ostensibly on the effects of a railway passing through Green- 
 wich Park, but really attacking almost everything that I did 
 in the Observatory. I replied to this on July 2ist by a letter 
 in the Athenaeum addressed to Sir Robert Inglis, in terms so 
 strong and so well supported that Sir James South was 
 effectually silenced." The following extract from a letter of 
 Airy's to the Earl of Rosse, dated Dec. I5th 1846, will shew 
 how pronounced the quarrel between Airy and South had 
 become in consequence of the above-mentioned attack and 
 previous differences : " After the public exposure which his 
 conduct in the last summer compelled me to make, I certainly 
 cannot meet him on equal terms, and desire not to meet him 
 at all." (Ed.)." In the Mag. and Met. Department, I was 
 constantly engaged with Mr Charles Brooke in the prepara- 
 tion and mounting of the self-registering instruments, and the 
 chemical arrangements for their use, to the end of the year. 
 With Mr Ronalds I was similarly engaged : but I had the 
 greatest difficulty in transacting business with him, from his 
 unpractical habits. The equipment of the Liverpool Obser- 
 vatory, under me, was still going on : I introduced the use of 
 Siemens's Chronometric Governor for giving horary motion to 
 an Equatoreal there. I have since introduced the same prin- 
 
 12 2 
 
180 GEORGE BIDDELL AIRY. 
 
 ciple in the Chronograph Barrel and the Great Equatoreal at 
 Greenwich : I consider it important. On Feb. I3th I received 
 the Astronomical Society's Medal for the Planetary Reduc- 
 tions. In the University of London : At this time seriously 
 began the discussion whether there should be a compulsory 
 examination in matters bearing on religious subjects. After 
 this there was no peace. For discovery of "Comets three 
 medals were awarded by Schumacher and me : one to 
 Peters, two to De Vico. A comet was seen by Hind, and 
 by no other observer : after correspondence, principally in 
 1848, the medal was refused to him. With respect to the 
 Railway Gauge Commission : On Jan. 1st, in our experi- 
 ments near York, the engine ran off the rails. On Jan. 2pth 
 the Commissioners signed the Report, and the business was 
 concluded by the end of April. Our recommendation was 
 that the narrow gauge should be carried throughout. This 
 was opposed most violently by partisans of the broad gauge, 
 and they had sufficient influence in Parliament to prevent our 
 recommendation from being carried into effect. But the 
 policy, even of the Great Western Railway (in which the 
 broad gauge originated), has supported our views : the narrow 
 gauge has been gradually substituted for the broad : and the 
 broad now (1872) scarcely exists. On June 2Oth Lord Can- 
 ning enquired of me about makers for the clock in the Clock 
 Tower of Westminster Palace. I suggested Vulliamy, Dent, 
 Whitehurst ; and made other suggestions : I had some cor- 
 respondence with E. B. Denison, about clocks. I had much 
 correspondence with Stephenson about the Tubular Bridge 
 over the Menai Straits. Stephenson afterwards spoke of my 
 assistance as having much supported him in this anxious 
 work: on Dec. nth I was requested to make a Report, and 
 to charge a fee as a Civil Engineer ; but I declined to do so. 
 In January I went, with George Arthur Biddell, to Portsmouth, 
 to examine Lord Dundonald's rotary engine as mounted in the 
 'Janus,' and made a Report on the same to the Admiralty: 
 and I made several subsequent Reports on the same matter. 
 
AT GREENWICH OBSERVATORY 1846 TO 1856. l8l 
 
 The scheme was abandoned in the course of next year ; the 
 real cause of failure, as I believe, was in the bad mounting in 
 the ship. 
 
 " The engrossing subject of this year was the discovery of 
 Neptune. As I have said (1845) I obtained no answer from 
 Adams to a letter of enquiry. Beginning with June 26th of 
 1846 I had correspondence of a satisfactory character with 
 Le Verrier, who had taken up the subject of the disturbance 
 of Uranus, and arrived at conclusions not very different from 
 those of Adams. I wrote from Ely on July gth to Challis, 
 begging him, as in possession of the largest telescope in Eng- 
 land, to sweep for the planet, and suggesting a plan. I 
 received information of its recognition by Galle, when I was 
 visiting Hansen at Gotha. For further official history, see my 
 communications to the Royal Astronomical Society, and for 
 private history see the papers in the Royal Observatory. I 
 was abused most savagely both by English and French." 
 
 The Report to the Visitors contains an interesting account 
 of the Great Lunar Reductions, from which the following 
 passage is extracted : " Of the Third Section, containing the 
 comparison of Observed Places with Tabular Places, three 
 sheets are printed, from 1750 to 1756. This comparison, it is 
 to be observed, does not contain a simple comparison of 
 places, but contains also the coefficients of the various 
 changes in the moon's place depending on changes in the 
 elements. . . . The process for the correction of the elements 
 by means of these comparisons is now going on : and the 
 extent of this work, even after so much has been prepared, 
 almost exceeds belief. For the longitude, ten columns are 
 added in groups, formed in thirteen different ways, each 
 different way having on the average about nine hundred 
 groups. For the ecliptic polar distance, five columns are 
 added in groups, formed in seven different ways, each 
 different way having on the average about nine hundred 
 groups. Thus it will appear that there are not fewer than 
 150,000 additions of columns of figures. This part of the 
 
1 82 GEORGE BIDDELL AIRY. 
 
 work is not only completed but is verified, so that the 
 books of comparison of Observed and Tabular Places are, 
 as regards this work, completely cleared out. The next step 
 is to take the means of these groiips, a process which is now 
 in hand : it will be followed by the formation and solution of 
 the equations on which the corrections of the elements 
 depend." 
 
 The following remarks, extracted from the Report to the 
 Visitors, with respect to the instrumental equipment of the 
 Observatory, embody the views of the Astronomer Royal at 
 this time : " The utmost change, which I contemplate as 
 likely to occur in many years, in regard to our meridional 
 instruments, is the substitution of instruments of the same 
 class carrying telescopes of larger aperture. The only in- 
 strument which,. as I think, may possibly be called for by the 
 demands of the astronomer or the astronomical public, is a 
 telescope of the largest size, for the observation of faint 
 nebulae and minute double stars. Whether the addition of 
 such an instrument to our apparatus would be an advantage, 
 is, in my opinion, not free from doubt. The line of conduct 
 for the Observatory is sufficiently well traced ; there can be 
 no doubt that our primary objects ought to be the accurate 
 determination of places of the fundamental Stars, the Sun, 
 the Planets, and, above all, the Moon. Any addition what- 
 ever to our powers or our instrumental luxuries, which should 
 tend to withdraw our energies from these objects, would be a 
 misfortune to the Observatory." 
 
 Of private history : " In March I visited Prof. Sedgwick at 
 Norwich. On Mar. 28th the ' Sir Henry Pottinger ' was 
 launched from Fairbairn's Yard on the Isle of Dogs, where I 
 was thrown down and dislocated my right thumb. From 
 Apr. 10th to 1 5th I was at Playford. On June loth Prof. 
 Hansen arrived, and stayed with me to July 4th. From 
 July 6th to loth I was visiting Dean Peacock at Ely. From 
 July 23rd to 29th I was at Playford, where for the first time 
 I lodged in my own cottage. I had bought it some time 
 
AT GREENWICH OBSERVATORY 1846 TO 1856. 183 
 
 before, and my sister had superintended alterations and the 
 addition of a room. I was much pleased thus to be connected 
 with the happy scenes of my youth. From Aug. loth to Oct. 
 nth I was with my wife and her sister Elizabeth Smith on 
 the Continent. We stayed for some time at Wiesbaden, as 
 my nerves were shaken by the work on the Railway Gauge 
 Commission, and I wanted the Wiesbaden waters. We 
 visited various places in Germany, and made a lo-days' 
 excursion among the Swiss Mountains. At Gotha we 
 lodged with Prof. Hansen for three days; and it was while 
 staying here that I heard from Prof. Encke (on Sept. 29th) 
 that Galle had discovered the expected planet. We visited 
 Gauss at Gottingen and Miss Caroline Herschel at Hannover. 
 We had a very bad passage from Hamburgh to London, last- 
 ing five days : a crank-pin broke and had to be repaired : 
 after four days our sea-sickness had gone off, during the 
 gale a valuable discovery for me, as I never afterwards 
 feared sea-sickness. On Dec. 22nd I attended the cele- 
 bration of the 3OOth anniversary of Trinity College." 
 
 The following extracts relating to the engines of the 
 " Janus " are taken from letters to his wife dated from Ports- 
 mouth, Jan. 6th and /th, 1846 : 
 
 As soon as possible we repaired to the Dock Yard and presented 
 ourselves to the Admiral Superintendant Admiral Hyde Parker (not 
 Sir Hyde Parker). Found that the " Janus " had not arrived : the 
 Admiral Superintendant (who does not spare a hard word) expressing 
 himself curiously thereon. But he had got the proper orders from 
 the Admiralty relating to me : so he immediately sent for Mr Taplin, 
 the Superintendant of machinery : and we went off to see the small 
 engine of Lord D d's construction which is working some pumps and 
 other machinery in the yard. It was kept at work a little longer than 
 usual for us to see it. And I have no hesitation in saying that it was 
 working extremely well. It had not been opened in any way for 
 half a year, and not for repair or packing for a much longer time. . . . 
 This morning we went to the Dock Yard, and on entering the 
 engine house there was Shirreff, and Lord D d soon appeared. The 
 
1 84 GEORGE BIDDELL AIRY. 
 
 " Janus" had come to anchor at Spithead late last night, and had 
 entered the harbour this morning. Blowing weather on Saturday 
 night. We had the engine pretty well pulled to pieces, and sat con- 
 templating her a long time., Before- this Denison had come to us. 
 We then went on board the "Janus * with Shirreff but not with Lord 
 D d. The engines were still hot, and so they were turned back- 
 wards a little for my edification. (This was convenient because, the 
 vessel being moored by her head, she could thus strain backwards 
 without doing mischief.) The vacuum not good. Then, after a 
 luncheon on board, it was agreed to run out a little way. But the 
 engines absolutely stuck fast, and would not stir a bit. This I con- 
 sidered a perfect Godsend. So the paddle-wheels (at my desire) 
 were lashed fast, and we are to see her opened to-morrow morning. 
 
 This morning (Jan. yth) we all went off to the " Janus," where we 
 expected to find the end of the cylinder (where we believe yesterday's 
 block to have taken place) withdrawn. But it was not near it. After 
 a great many bolts were drawn, it was discovered that one bolt could 
 not be drawn, and in order to get room for working at it, it was 
 necessary to take off the end of the other cylinder. And such a job ! 
 Three pulley hooks were broken in my sight, and I believe some out 
 of my sight. However this auxiliary end was at last got off : and the 
 people began to act on the refractory bolt. But by this time it was 
 getting dark and the men were leaving the dockyard, so I left, 
 arranging that what they could do in preparation for me might be 
 done in good time to-morrow morning. 
 
 1847 
 
 "On Nov. 1 3th I circulated an Address, proposing to 
 discontinue the use of the Zenith Tube, because it had been 
 found by a long course of comparative trials that the Zenith 
 Tube was not more accurate than the Mural Circle. The 
 Address stated that ' This want of superior efficiency of the 
 Zenith Tube (which, considered in reference to the expecta- 
 tions that had been formed of its accuracy, must be estimated 
 as a positive failure) is probably due to two circumstances. 
 One is, the use of a plumb-line ; which appears to be affected 
 with various ill-understood causes of unsteadiness. The 
 other is, the insuperable difficulty of ventilating the room in 
 
AT GREENWICH OBSERVATORY 1846 TO 1856. 185 
 
 which the instrument is mounted.' On December 2Oth I 
 circulated an Address, proposing a Transit Circle, with 
 telescope of 8 inches aperture. The Address states as 
 follows : ' The clear aperture of the Object-Glass of our 
 Transit Instrument is very nearly 5 inches, that of our Mural 
 Circle is very nearly 4 inches.' I had been requested by the 
 Master-General of Ordnance (I think) to examine Candidates 
 for a Mastership in Woolwich Academy, and I was employed 
 on it in February and March, in conjunction with Prof. 
 Christie. In January I applied to Lord Auckland for 
 money-assistance to make an astronomical journey on the 
 Continent, but he refused. On Mar. igth Sir James South 
 addressed to the Admiralty a formal complaint against me 
 for not observing with the astronomical instruments : on 
 Mar. 3 ist I was triumphantly acquitted by the Admiralty. 
 In June I was requested by the Commissioners of Railways 
 to act as President of a Commission on Iron Bridges 
 (suggested by the fall of the bridge at Chester). Lord 
 Auckland objected to it, and I was not sorry to be spared 
 the trouble of it. In December I was requested, and under- 
 took to prepare the Astronomical part of the Scientific 
 Manual for Naval Officers. On Sept. 24th occurred a very 
 remarkable Magnetic Storm, to which there had been nothing 
 comparable before. Mr Glaisher had it observed by eye 
 extremely well, and I printed and circulated a paper con- 
 cerning it. Hansen, stimulated by the Lunar Reductions, 
 discovered two long inequalities in the motion of the Moon, 
 produced by the action of Venus. In the Report to the 
 Visitors this matter is thus referred to : 'In the last summer 
 I had the pleasure of visiting Prof. Hansen at Gotha, and I 
 was so fortunate as to exhibit to him the corrections of the 
 elements from these Reductions, and strongly to call his 
 attention to their certainty, the peculiarity of their fluctua- 
 tions, and the necessity of seeking for some physical explana- 
 tion. I have much pleasure in indulging in the thought, that 
 it was mainly owing to this representation that Prof. Hansen 
 
1 86 GEORGE BIDDELL AIRY. 
 
 undertook that quest, which has terminated in the discovery 
 of his two new lunar inequalities, the most remarkable 
 discovery, I think, in Physical Astronomy.' In discussing 
 points relating to the discovery 0f Neptune, I made an un- 
 fortunate blunder. In a paper hastily sent to the Athenaeum 
 (Feb. 1 8th) I said that Arago's conduct had been indelicate. 
 I perceived instantly that I had used a wrong expression, 
 and by the very next post I sent an altered expression. 
 This altered expression was not received in time, and the 
 original expression was printed, to my great sorrow. I 
 could not then apologize. But at what appeared to be the 
 first opportunity, in December, I did apologize; and my 
 apology was accepted. But I think that Arago was never 
 again so cordial as before. On July 4th Hebe was discovered. 
 After this Iris and Flora. Now commenced that train of 
 discoveries which has added more than 100 planets to the 
 Solar System. On Oct. 8th was an Annular Eclipse of the 
 Sun, of which the limit of annularity passed near to Green- 
 wich. To determine the exact place, I equipped obser- 
 vatories at Hayes, Lewisham South End, Lewisham Village, 
 Blackwall, Stratford, Walthamstow, and Chingford. The 
 weather was bad and no observation was obtained. In the 
 Royal Astronomical Society: In 1846, the dispute between 
 the partisans of Adams and Le Verrier was so violent that no 
 medal could be awarded to either. In 1847 I (with other 
 Fellows of the Society) promoted a special Meeting for con- 
 sidering such a modification of the bye-laws that for this 
 occasion only it might be permissible to give two medals. 
 After two days' stormy discussion, it was rejected. In the 
 University of London : At a meeting in July, where the 
 religious question was discussed, it was proposed to receive 
 some testimonial from affiliated bodies, or to consider that or 
 some other plan for introducing religious literature. As the 
 propriety of this was doubtful, there was a general feeling for 
 taking legal advice: and it was set aside solely on purpose to 
 raise the question about legal consultation. That was nega- 
 
AT GREENWICH OBSERVATORY 1846 TO 1856. 1 87 
 
 tived by vote : and I then claimed the consideration of the 
 question which we had put aside for it. By the influence of 
 H. Warburton, M.P., this was denied. I wrote a letter to be 
 laid before the Meeting on July 28th, when I was necessarily 
 absent, urging my claim : my letter was put aside. I 
 determined never to sit with Warburton again : on Aug. 2nd 
 I intimated to Lord Burlington my wish to retire, and on 
 Aug. 2Qth he transmitted to the Home Secretary my resig- 
 nation. He (Lord Burlington) fully expressed his opinion 
 that my claim ought to have been allowed. On June Qth, on 
 the occasion of Prince Albert's state visit to Cambridge, 
 knighthood was offered to me through his Secretary, Prof. 
 Sedgwick, but I declined it. In September, the Russian 
 Order of St Stanislas was offered to me, Mr De Berg, the 
 Secretary of Embassy, coming to Greenwich personally to 
 announce it: but I was compelled by our Government 
 Rules to decline it. I invited Le Verrier to England, and 
 escorted him to the Meeting of the British Association at 
 Oxford in June. As regards the Westminster Clock on the 
 Parliamentary Building: in May I examined and re- 
 ported on Dent's and Whitehurst's clock factories. Vulliamy 
 was excessively angry with me. On May 3ist a great 
 Parliamentary Paper was prepared in return to an Order of 
 the House of Lords for correspondence relating to the Clock. 
 With respect to the Saw Mills for Ship Timber: work 
 was going on under the direction of Sylvester to Mar. i8th. 
 It was, I believe, at that time, that the fire occurred in 
 Chatham Dock Yard which burnt the whole of the saw- 
 machinery. I was tired of my machinery : and, from the 
 extending use of iron ships, the probable value of it was 
 much diminished ; and I made no effort to restore it." 
 
 Of private history : " In February I went to Derby to see 
 Whitehurst's clock factory ; and went on with my wife to 
 Brampton near Chesterfield, where her mother was living. 
 From Apr. 1st to 5th I was at Playford. On Holy Thursday, 
 I walked the Parish Bounds (of Greenwich) with the Parish 
 
1 88 GEORGE BIDDELL AIRY. 
 
 officers and others. From Apr. igth to 24th I was at Birming- 
 ham (on a visit to Guest, my former pupil, and afterwards 
 Master of Caius College) and its neighbourhood, with George 
 Arthur Biddell. From June 23^ to 28th I was at Oxford 
 and Malvern : my sister was at Malvern, for water-cure : the 
 meeting of the British Association was at Oxford and I 
 escorted Le Verrier thither. July 28th to 3Oth I was at 
 Brampton. From August loth to September i8th I was 
 engaged on an expedition to St Petersburg, chiefly with the 
 object of inspecting the Pulkowa Observatory. I went by 
 Hamburg to Altona, where I met Struve, and started with 
 him in an open waggon for Liibeck, where we arrived on 
 Aug. 1 4th. We proceeded by steamer to Cronstadt and 
 Petersburg, and so to Pulkowa, where I lodged with O. 
 Struve. I was -here engaged till Sept. 4th, in the Obser- 
 vatory, in expeditions in the neighbourhood and at St 
 Petersburg, and at dinner-parties, &c. I met Count 
 Colloredo, Count Ouvaroff, Count StroganofF, Lord Bloom- 
 field (British Ambassador), and others. On Sept. 4th I went 
 in a small steamer to Cronstadt, and then in the Vladimir 
 to Swinemiinde: we were then towed in a passage boat to 
 Stettin, and I proceeded by railway to Berlin. On Sept. 
 9th I found Galle and saw the Observatory. On Sept. loth 
 I went to Potzdam and saw Humboldt. On the I2th I went 
 to Hamburg and lodged with Schumacher : I here visited 
 Repsold and Rumker. On Sept. I4th I embarked in the 
 John Bull for London, and arrived there on the evening of 
 the 1 8th: on the i6th it was blowing 'a whole gale,' 
 reported to be the heaviest gale known for so many hours ; 
 4 bullocks and 24 sheep were thrown overboard. From Dec. 
 3rd to 8th I was at Cambridge, and from the 22nd to 3ist at 
 Playford." 
 
 Here is a letter to his wife written from Birmingham, 
 containing a note of the progress of the ironwork for the 
 Menai Bridge : 
 
AT GREENWICH OBSERVATORY 1846 TO 1856. 189 
 
 EDGBASTON, BIRMINGHAM, 
 1847, Apr. 22. 
 
 Yesterday morning we started between 10 and n for Stourbridge, 
 first to see some clay which is celebrated all over the world as the 
 only clay which is fit to make pots for melting glass, &c. You know 
 that in all these fiery regions, fire-clay is a thing of very great im- 
 portance, as no furnace will stand if made of any ordinary bricks 
 (and even with the fire-clay, the small furnaces are examined every 
 week), but this Stourbridge clay is as superior to fire-clay as fire-clay 
 is to common brick-earth. Then we went to Fosters' puddling and 
 rolling works near Stourbridge. These are on a very large scale : of 
 course much that we saw was a repetition of what we had seen before, 
 but there were slitting mills, machines for rolling the puddled blooms 
 instead of hammering them, &c., and we had the satisfaction of 
 handling the puddling irons ourselves. Then we went to another 
 work of the Fosters not far from Dudley, where part of the work of 
 the Tube Bridge for the Menai is going on. The Fosters are, I 
 believe, the largest iron masters in the country, and the two principal 
 partners, the elder Mr Foster and his Nephew, accompanied us in 
 all our inspections and steppings from one set of works to another. 
 The length of Tube Bridge which they have in hand here is only 
 1 20 feet, about \ of the whole length: and at present they are only 
 busy on the bottom part of it : but it is a prodigious thing. I shall 
 be anxious about it. Then we went to other works of the Fosters' 
 at King's Wynford, where they have blast furnaces: and here after 
 seeing all other usual things we saw the furnaces tapped. In this 
 district the Fosters work the lo-yard coal in a way different from 
 any body else: they work out the upper half of its thickness and 
 then leave the ground to fall in: after a year or two this ground 
 becomes so hard as to make a good safe roof, and then they work 
 away the other half: thus they avoid much of the danger and diffi- 
 culty of working the thick bed all at once. The ventilation of these 
 mines scarcely ever requires fires, and then only what they call 
 "lamps," those little fire-places which are used for giving light at 
 night. (In the Northumberland and Durham pits, they constantly 
 have immense roaring fires to make a draught.) Then we came 
 home through Dudley. 
 
190 GEORGE BIDDELL AIRY. 
 
 During his stay in Russia, there was a great desire 
 manifested by the astronomers and scientific men of Russia 
 that he should be presented to the Emperor. This would no 
 doubt have taken place had not tj*e movements of the Court 
 and his own want of time prevented it. The following 
 letter to the British Ambassador, Lord Bloomfield, relates to 
 this matter : 
 
 PULKOWA, 
 1847, August 2$th. 
 Wednesday evening. 
 MY LORD, 
 
 I had the honour yesterday to receive your Lordship's 
 note of Sunday last, which by some irregularity in the communi- 
 cations with this place reached me, I believe, later than it ought. 
 From this circumstance, and also from my being made acquainted 
 only this afternoon with some official arrangements, I am compelled 
 to trouble you at a time which I fear is less convenient than I could 
 have desired. 
 
 The object of my present communication is, to ask whether (if 
 the movements of the Court permit it) it would be agreeable to your 
 Lordship to present me to the Emperor. In explanation of this 
 enquiry, I beg leave to state that this is an honour to which, 
 personally, I could not think of aspiring. My presence however at 
 Pulkowa at this time is in an official character. As Astronomer 
 Royal of England, I have thought it my duty to make myself 
 perfectly acquainted with the Observatory of Pulkowa, and this is 
 the sole object of my journey to Russia. It is understood that the 
 Emperor takes great interest in the reputation of the Observatory, 
 and I am confident that the remarks upon it which I am able to 
 make would be agreeable to him. 
 
 I place these reasons before you, awaiting entirely Your Lord- 
 ship's decision on the propriety of the step to which I have alluded. 
 I am to leave St Petersburg on Saturday the 4th of Septeoiber. 
 
 I have the honor to be 
 
 My Lord, 
 Your Lordship's very faithful servant, 
 
 G. B. AIRY. 
 
 Lord Bloomfield, 6^., 6<r. 
 
AT GREENWICH OBSERVATORY 1846 TO 1856. 191 
 
 It was probably in acknowledgment of this letter that in 
 due time he received the following letter with the offer of the 
 Russian Order of St Stanislas : 
 
 MONSIEUR L'ASTRONOME ROYAL, 
 
 Sa Majeste 1'Empereur en appre'ciant les travaux assidus 
 qui vous ont donn une place distinguee au rang des plus illustres 
 Astronomes de 1'Europe, et la cooperation bienveillante, que vous 
 n'avez cesse de temoigner aux Astronomes Russes dans les expe- 
 ditions, dont ils etaient charge's, et en dernier lieu par votre visite a 
 1'Observatoire central de Poulkova, a daigne sur mon rapport, vous 
 nommer Chevalier de la seconde classe de POrdre Imperial et 
 Royal de St Stanislas. Je ne manquerai pas de vous faire parvenir 
 par 1'entremise de Lord Bloomfield les insignes et la patente de 
 1'ordre. 
 
 Veuillez en attendant, Monsieur, recevoir mes sinceres felici- 
 tations et 1'assurance de ma parfaite consideration. 
 
 Le Ministre de 1'instruction publique, 
 
 CTE OUVAROFF. 
 ST PETERSBOURG, 
 24 A out 
 
 a Mr G. B. Airy, Esq., 
 Astronome Royal de S. M. Britannique a 
 
 Greenwich. 
 
 Airy provisionally accepted the Order, but wrote at once 
 to Lord John Russell the following letter of enquiry : 
 
 ROYAL OBSERVATORY, GREENWICH, 
 
 1847, Oct. 15. 
 MY LORD, 
 
 In respect of the office of Astronomer Royal, I refer 
 to the first Lord of the Treasury as Official Patron. In virtue of this 
 relation I have the honour to lay before your Lordship the following 
 statement, and to solicit your instructions thereon. 
 
 For conducting with efficiency and with credit to the nation the 
 institution which is entrusted to me, I have judged it proper to 
 cultivate intimate relations with the principal Observatories of 
 
IQ2 GEORGE BIDDELL ATRY. 
 
 Europe, and in particular with the great Observatory founded by the 
 Emperor of Russia at Pulkowa near St Petersburg. I have several 
 times received Mr Struve, the Director of that Observatory, at 
 Greenwich: and in the past summer I made a journey to St 
 Petersburg for the purpose of seeing the Observatory of Pulkowa. 
 
 Since my return from Russia, I have received a communication 
 from Count Ouvaroff, Minister of Public Instruction in the Russian 
 Empire, informing me that the Emperor of Russia desires to confer 
 on me the decoration of Knight Commander in the second rank of 
 the Order of St Stanislas. 
 
 And I have the honour now to enquire of your Lordship whether 
 it is permitted to me to accept from the Emperor of Russia this 
 decoration. 
 
 I have the honour to be, 
 
 My Lord, 
 Your Lordship's very obedient servant, 
 
 G. B. AIRY. 
 The Rt Honble Lord John Russell, 
 
 &c. &c. &*c. 
 First Lord of the Treasury. 
 
 The answer was as follows : 
 
 DOWNING STREET, 
 October 19, 1847. 
 SIR, 
 
 I am desired by Lord John Russell to acknowledge the 
 receipt of your letter, of the i4th inst. and to transmit to you the 
 enclosed paper respecting Foreign Orders by which you will per- 
 ceive that it would be contrary to the regulations to grant you the 
 permission you desire. 
 
 I am, Sir, 
 Your obedient servant, 
 
 C. A. GREY. 
 G. B. Airy, Esq. 
 
 The passage in the Regulations referred to above is 
 quoted in the following letter to Count Ouvaroff: 
 
AT GREENWICH OBSERVATORY 1846 TO 1856. 193 
 
 ROYAL OBSERVATORY, GREENWICH, 
 
 1847, Oct. 22. 
 SIR, 
 
 Referring to your Excellency's letter of the ^ \JT > 
 
 to my answer of the 25th September, in which I expressed my sense 
 of the high honor conferred on me by His Majesty the Emperor of 
 Russia in offering me, through your Excellency, the Order of St 
 Stanislas, and my pride in accepting it: I beg leave further to 
 acquaint you that I have thought it necessary to make enquiry of 
 Lord John Russell, First Lord of Her Majesty's Treasury, as to my 
 competency to accept this decoration from His Majesty the Emperor 
 of Russia: and that his Lordship in reply has referred me to the 
 following Regulation of the British Court; 
 
 "5th. That no Subject of Her Majesty could be allowed to 
 accept the Insignia of a Foreign Order from any Sovereign of a 
 Foreign State, except they shall be so conferred in consequence of 
 active and distinguished services before the Enemy, either at Sea, or 
 in the Field ; or unless he shall have been actually employed in the 
 Service of the Foreign Sovereign." 
 
 In consequence of the stringency of this Regulation, it is my 
 duty now to state to your Excellency that I am unable to accept the 
 decoration which His Majesty the Emperor of Russia was pleased, 
 through your Excellency, to offer to me. 
 
 I beg leave to repeat the expression of my profound reverence 
 to His Majesty and of my deep sense of the honor which he has 
 done me. 
 
 I have the honor to be, 
 
 Sir, 
 Your Excellency's very faithful 
 
 and obedient servant, 
 
 G. B. AIRY. 
 To His Excellency 
 Count Ouvaroff) 
 
 In the course of the following year a very handsome gold 
 medal, specially struck, was transmitted by Count Ouvaroff 
 on the part of the Emperor of Russia, to Mr Airy. 
 
 A. B. 13 
 
194 GEORGE BIDDELL AIRY. 
 
 1848 
 
 " In April I received Authority to purchase of Simms an 
 8-inch object-glass for the new Transit Circle for 300. The 
 glass was tested and found satisfactory. While at Playford 
 in January I drew the first plans of the Transit Circle : and 
 C. May sketched some parts. Definite plans were soon sent to 
 Ransomes and May, and to Simms in March. The instru- 
 ment and the building were proceeded with during the year. 
 The New Transit Circle was to be erected in the Circle 
 Room, and considerable arrangement was necessary for 
 continuing the Circle Observations with the existing instru- 
 ments, whilst the new instrument was under erection. When 
 the new Transit is completely mounted, the old Transit 
 Instrument may be removed, and the Transit Room will 
 be free for any other purpose. I propose to take it as 
 Private Room for the Astronomer Royal. On May I2th I 
 made my first proposal of the Reflex Zenith Tube. The 
 principle of it is as follows : Let the micrometer be placed 
 close to the object-glass, the frame of the micrometer being 
 firmly connected with the object-glass cell, and a reflecting 
 eye-piece being used with no material tube passing over the 
 object-glass : and let a basin of quicksilver be placed below 
 the object-glass, but in no mechanical connection with it, at a 
 distance equal to half the focal length of the object-glass. 
 Such an instrument would at least be free from all uncertain- 
 ties of twist of plumb-line, viscosity of water, attachment of 
 upper plumb-line microscope, attachment of lower plumb-line 
 microscope, and the observations connected with them : and 
 might be expected, as a result of this extreme simplicity, to 
 give accurate results. A considerable error was discovered 
 in the graduation of Troughton's Circle, amounting in one 
 part to six seconds, which is referred to as follows : ' This 
 instance has strongly confirmed me in an opinion which I 
 have long held that no independent division is comparable 
 
AT GREENWICH OBSERVATORY 1846 TO 1856. 195 
 
 in general accuracy to engine-division, where the fundamental 
 divisions of the engine have been made by Troughton's 
 method, and where in any case the determination by the 
 astronomer of errors of a few divisions will suffice, in conse- 
 quence of the uniformity of law of error, to give the errors of 
 the intermediate divisions.' The method of observing with 
 the Altazimuth is carefully described, and the effect of it, in 
 increasing the number of observations of the Moon, is thus 
 given for the thirteen lunations between 1847, May 15, and 
 1848, May 30. 'Number of days of complete observations 
 with the Meridional Instruments, in ; number of days of 
 complete observations with Altitude and Azimuth Instru- 
 ment, 203. The results of the observations appear very good ; 
 perhaps a little, and but a little, inferior to those of the 
 Meridional Instruments. I consider that the object for 
 which this instrument was erected is successfully attained.' 
 Being satisfied with the general efficiency of the system 
 arranged by Mr Brooke for our photographic records (of 
 magnetical observations) I wrote to the Admiralty in his 
 favour, and on Aug. 25th the Admiralty ordered the pay- 
 ment of ^500 to him. A Committee of the Royal Society 
 also recommended a reward of 250 to Mr Ronalds, which I 
 believe was paid to him. On May 1st the last revise of the 
 Lunar Reductions was passed, and on May 5th, 500 copies 
 were sent for binding. In this year Schumacher and I 
 refused a medal to Miss Mitchell for a Comet discovered, 
 because the rules of correspondence had not been strictly 
 followed : the King of Denmark gave one by special favour. 
 In this year occurred the discovery of Saturn's 8th Satellite 
 by Mr Lassell : upon which I have various correspondence. 
 On the 1 8th of December the degree of LL.D. was conferred 
 upon me by the University of Edinburgh. The Ipswich 
 Lectures: A wish had been expressed that I would give a 
 series of Astronomical Lectures to the people of Ipswich. I 
 therefore arranged with great care the necessary apparatus, 
 and lectured six evenings in a room (I forget its name it 
 
 132 
 
196 GEORGE BIDDELL AIRY. 
 
 might be Temperance Hall high above St Matthew's 
 Street), from Mar. 1 3th to the end of the week. A short- 
 hand writer took them down : and these formed the ' Ipswich 
 Lectures,' which were afterwards published by the Ipswich 
 Museum (for whose benefit the lectures were given) and by 
 myself, in several editions, and afterwards by Messrs Macmillan 
 in repeated editions under the title of ' Airy's Popular As- 
 tronomy.' It had been found necessary to include under 
 one body all the unconnected Commissions of Sewers for 
 the Metropolis, and Lord Morpeth requested me to be a 
 member. Its operations began on Oct. 28th. In constitu- 
 tion it was the most foolish that I ever knew : consisting of, 
 I think, some 200 persons, who could not possibly attend to 
 it. It came to an end in the next year." 
 
 Of private history : " I was at Playford from Jan. 1st to 
 nth, and again from Jan. i/th to 25th: also at Playford from 
 June 2 ist to July I2th. From Aug. 23rd to Sept. I2th I was 
 in Ireland on a visit to Lord Rosse at Parsonstown, chiefly 
 engaged on trials of his large telescope. I returned by Liver- 
 pool, where I inspected the Liverpool Equatoreal and Clock- 
 work, and examined Mr Lassell's telescopes and grinding 
 apparatus. From Dec. 6th to 2Oth I was at Edinburgh with 
 my wife, on a visit to Prof. J. D. Forbes. We made various 
 excursions, and I attended lectures by Prof. Wilson and Sir 
 W. Hamilton : on the i8th I gave a lecture in Prof. Forbes's 
 room. I received the Honorary Degree of LL.D., and made 
 a statement on the Telescopes of Lord Rosse and Mr Lassell 
 to the Royal Society of Edinburgh. Returned to Greenwich 
 by Brampton." 
 
 Here is a reminiscence of the " Ipswich Lectures," in a 
 letter to his wife, dated Playford, 1848 Mar. 14, "At the 
 proper time I went to the hall : found a chairman installed 
 (Mr Western) : was presented to him, and by him presented 
 to the audience : made my bow and commenced. The room 
 
AT GREENWICH OBSERVATORY 1846 TO 1856, 197 
 
 was quite full : I have rarely seen such a sea of faces ; about 
 700 I believe. Everything went off extremely well, except 
 that the rollers of the moving piece of sky would squeak : 
 but people did not mind it : and when first a star passed the 
 meridian, then Jupiter, then some stars, and then Saturn, he 
 was much applauded. Before beginning I gave notice that I 
 should wait to answer questions : and as soon as the lecture 
 was finished the Chairman repeated this and begged people 
 to ask. So several people did ask very pertinent questions 
 (from the benches) shewing that they had attended well. 
 Others came up and asked questions." 
 
 The following extracts are from letters written to his 
 wife while on his visit to Lord Rosse at Parsonstown in 
 Ireland. On the way he stopped at Bangor and looked at 
 the Tubular Bridge Works, which are thus referred to: 
 " Stopped at Bangor, settled pro tern, at the Castle, and then 
 walked past the Suspension Bridge towards the Tube Works, 
 which are about ij mile south-west of the Suspension Bridge. 
 The way was by a path through fields near the water side : 
 and from one or two points in this, the appearance of the 
 Suspension Bridge was most majestic. The Tube Bridge 
 consists of four spans, two over water and two over sloping 
 land. The parts for the double tube over the water spans 
 (four lengths of tube) are building on a platform as at Con- 
 way, to be floated by barges as there : the parts over the 
 sloping banks are to be built in their place, on an immense 
 scaffolding. I suspect that, in regard to these parts, Stephen- 
 son is sacrificing a great deal of money to uniformity of plan : 
 and that it would have been much cheaper to build out stone 
 
 arches to the piers touching the water The Tube Works 
 
 are evidently the grand promenade of the idlers about Bangor : 
 I saw many scores of ladies and gentlemen walking that way 
 with their baskets of provision, evidently going to gipsy in 
 the fields close by." 
 
198 GEORGE BIDDELL AIRY. 
 
 THE CASTLE, PARSONSTOWN, 
 
 1848, Aug. 29. 
 
 After tea it was voted that the night was likely to be fine, so we 
 all turned out. The night was uncertain : sometimes entirely clouded, 
 sometimes partially, but objects were pretty well seen when the sky 
 was clear : the latter part was much steadier. From the interruption 
 by clouds, the slowness of finding with and managing a large instru- 
 ment (especially as their finding apparatus is not perfectly arranged) 
 and the desire of looking well at an object when we had got it, we 
 did not look at many objects. The principal were, Saturn and the 
 Annular Nebula of Lyra with the 3-feet ; Saturn, a remarkable cluster 
 of stars, and a remarkable planetary nebula, with the 6-feet. With 
 the large telescope, the evidence of the quantity of light is prodigious. 
 And the light of an object is seen in the field without any colour or 
 any spreading of stray light : and it is easy to see that the vision 
 with a reflecting telescope may be much more perfect than with 
 a refractor. With these large apertures, the rings round the stars 
 are insensible. The planetary nebula looked a mass of living and 
 intensely brilliant light : this is an object which I do not suppose 
 can be seen at all in our ordinary telescopes. The definition of the 
 stars near the zenith is extremely good : with a high power (as 800) 
 they are points or very nearly so indeed I believe quite so so that 
 it is clear that the whole light from the great 6-feet mirror is collected 
 into a space not bigger than the point of a needle. But in other 
 positions of the telescope the definition is not good : and we must 
 look to-day to see what is the cause of this fault. It is not a fault in 
 the telescope, properly so-called, but it is either a tilt of the mirror, 
 or an edge-pressure upon the mirror when the telescope points lower 
 down which distorts its figure, or something of that kind. So I could 
 not see Saturn at all well, for which I was sorry, as I could so well 
 have compared his appearance with what I have seen before. I shall 
 be very much pleased if we can make out what is the fault of ad- 
 justment, and so correct it as to get good images everywhere. It is 
 evident that the figuring of the mirror, the polishing, and the general 
 arrangement, are perfectly managed. 
 
AT GREENWICH OBSERVATORY 1846 TO 1856. 199 
 
 THE CASTLE, PARSONSTOWN, 
 
 1848, Aug. 30. 
 
 Yesterday we were employed entirely about the Great Telescope, 
 beginning rather late. The principal objects had relation to the 
 fault of definition when the telescope is pointed low (which I had 
 remarked on the preceding night), and were, to make ourselves 
 acquainted with the mechanism of the mirror's mounting generally, 
 and to measure in various ways whether the mirror actually does shift 
 its place when the telescope is set to different angles of elevation. 
 For the latter we found that the mirror actually does tilt \ of an inch 
 when the tube points low. This of itself will not account for the 
 fault but it indicates that the lower part is held fast in a way that may 
 cause a strain which would produce the fault. These operations and 
 reasonings took a good deal of time. Lord Rosse is disposed to 
 make an alteration in the mounting for the purpose of correcting 
 this possible strain. 
 
 THE CASTLE, PARSONSTOWN, 
 
 1848, Aug. 31. 
 
 The weather here is still vexatious : but not absolutely repulsive. 
 Yesterday morning Lord Rosse arranged a new method of suspend- 
 ing the great mirror, so as to take its edgewise pressure in a manner 
 that allowed the springy supports of its flat back to act. This em- 
 ployed his workmen all day, so that the proposed finish of polishing 
 the new mirror could not go on. I took one Camera Lucida sketch 
 of the instrument in the morning, dodging the heavy showers as well 
 as I could; then, as the afternoon was extremely fine, I took 
 another, with my head almost roasted by the sun. This last view is 
 extremely pretty and characteristic, embracing parts of the mounting 
 not shewn well in the others, and also shewing the Castle, the 
 Observatory, and the 3 -feet telescope. The night promised exceed- 
 ingly well : but when we got actually to the telescope it began to 
 cloud and at length became hopeless. However I saw that the fault 
 which I had remarked on the two preceding nights was gone. There 
 is now a slight exhibition of another fault to a much smaller extent. 
 We shall probably be looking at the telescope to-day in reference 
 to it. 
 
200 GEORGE BIDDELL AIRY. 
 
 THE CASTLE, PARSONSTOWN, 
 
 1848, Sept. i. 
 
 A 
 
 Yesterday we made some alterations in the mounting of the great 
 mirror. We found that sundry levers were loose which ought to be 
 firm, and we conjectured with great probability the cause of this, for 
 correction of which a change in other parts was necessary. The 
 mirror was then found to preserve its position much more fixedly 
 than before. ... . At night, upon trying the telescope, we found it 
 very faulty for stars near the zenith, where it had been free from fault 
 before. The screws which we had driven hard were then loosened, 
 and immediately it was made very good. Then we tried with some 
 lower objects, and it was good, almost equally good, there. For 
 Saturn it was very greatly superior to what it had been before. Still 
 it is not satisfactory to us, and at this time a strong chain is in pre- 
 paration, to support the mirror edgeways instead of the posts that 
 there were at first or the iron hoop which we had on it yesterday. 
 
 Nobody would have conceived that an edgewise gripe of such a 
 mass of metal could derange its form in this way. 
 
 Last night was the finest night we have had as regards clouds, 
 though perhaps not the best for definition of objects. 
 
 THE CASTLE, PARSONSTOWN, 
 
 1848, Sept. 2. 
 
 I cannot learn that the fault in the mirror had been noticed 
 before, but I fancy that the observations had been very much con- 
 fined to the Zenith and its neighbourhood. 
 
 1849 
 
 " In July the new constant-service water-pipes to the 
 Observatory were laid from Blackheath. Before this time 
 the supply of water to the Observatory had been made by a 
 pipe leading up from the lower part of the Park, and was not 
 constant. In May the new staircase from my dwelling-house 
 to the Octagon Room was commenced. In the Report to 
 the Visitors there is a curious account of Mr Breen's (one of 
 
AT GREENWICH OBSERVATORY 1846 TO 1856. 2OI 
 
 the Assistants) personal equation, which was found to be 
 different in quantity for observations of the Moon and obser- 
 vations of the Stars. The most important set of observations 
 (of planets) was a series of measures of Saturn in four direc- 
 tions, at the time when his ring had disappeared. They 
 appear completely to negative the idea that Saturn's form 
 differs sensibly from an ellipsoid. Among the General 
 Remarks of the Report the following appears : ' Another 
 change (in prospect) will depend on the use of galvanism ; 
 and as a probable instance of the application of this agent, I 
 may mention that, although no positive step has hitherto 
 been taken, I fully expect in no long time to make the going 
 of all the clocks in the Observatory depend on one original 
 regulator. The same means will probably be employed to 
 increase the general utility of the Observatory, by the exten- 
 sive dissemination throughout the kingdom of accurate time- 
 signals, moved by an original clock at the Royal Observa- 
 tory; and I have already entered into correspondence with 
 the authorities of the South Eastern Railway (whose line of 
 galvanic communication will shortly pass within nine furlongs 
 of the Observatory) in reference to this subject.' I agreed 
 with Schumacher in giving no medal to Mr G. P. Bond ; his 
 comet was found to be Petersen's. Five medals were awarded 
 for comets in 1847 (Hind, Colla, Mauvais, Brorsen, Schweizer). 
 The Liverpool Observatory was finished this year : and the 
 thanks of the Town Council were presented to me. Respect- 
 ing Fallows's Observations at the Cape of Good Hope : I 
 had received the Admiralty sanction for proceeding with 
 calculations in 1846, and I employed computers as was con- 
 venient. On July 20th of this year 1 was ready with final 
 results, and began to make enquiries about Fallows's personal 
 history, and the early history of the Cape Observatory. On 
 Oct. 23rd I applied for sanction for printing, which was given, 
 and the work was soon finished off, in the Astronomical 
 Society's Memoirs. In the month of March I had com- 
 menced correspondence with various persons on the imperfect 
 
202 GEORGE BIDDELL AIRY. 
 
 state of publication of the British Survey. Sheets of the 
 Map were issued by scores, but not one of them had an indi- 
 cation of latitude or longitude engraved. I knew that great 
 pains had been taken in giving to* the principal triangulation 
 a degree of accuracy never before reached, and in fixing the 
 astronomical latitudes of many stations with unequalled pre- 
 cision. Finally 1 prepared for the Council "of the Royal 
 Society a very strong representation on these subjects, which 
 was adopted and presented to the Government. It was 
 entirely successful, and the Maps were in future furnished 
 with latitude and longitude lines. I was elected President 
 of the Royal Astronomical Society on Feb. gih. In June I 
 went with Sheepshanks to see some of the operation of 
 measuring a Base on Salisbury Plain. The following extract 
 from a letter to his wife dated 1849, June 2/th, relates to this 
 expedition : ' In the morning we started before eight in an 
 open carriage to the Plain : looking into Old Sarum on our 
 way. The Base is measured on what I should think a most 
 unfavourable line, its north end (from which they have begun 
 now, in verification of the old measure) being the very highest 
 point in the whole plain, called Beacon Hill. The soldiers 
 measure only 252 feet in a day, so it will take them a good 
 while to measure the whole seven miles. While we were 
 there Col. Hall (Colby's successor) and Yolland and Cosset 
 came.'" 
 
 Of private history : " I made short visits to Playford in 
 January, April and July. From July 28th to Sept. I2th I 
 made an expedition with my wife to Orkney and Shetland. 
 From Dec. 24th to 26th I was at Hawkhurst, on a visit to 
 Sir John Herschel." 
 
 1850 
 
 "The Report to the Board of Visitors opens with the 
 following paragraph : ' In recording the proceedings at the 
 Royal Observatory during the last year, I have less of novelty 
 
AT GREENWICH OBSERVATORY 1846 TO 1856. 203 
 
 to communicate to the Visitors than in the Reports of several 
 years past. Still I trust that the present Report will not be 
 uninteresting ; as exhibiting, I hope, a steady and vigorous 
 adherence to a general plan long since matured, accompanied 
 with a reasonable watchfulness for the introduction of new 
 instruments and new methods when they may seem desirable.' 
 Since the introduction of the self-registering instruments a 
 good many experiments had been made to obtain the most 
 suitable light, and the Report states that ' No change what- 
 ever has been made in these instruments, except by the 
 introduction of the light of coal-gas charged with the vapour 
 of coal-naptha, for photographic self-registration both of the 
 magnetic and of the meteorological instruments.... The chemi- 
 cal treatment of the paper is now so well understood by the 
 Assistants that a failure is almost unknown. And, generally 
 speaking, the photographs are most beautiful, and give con- 
 ceptions of the continual disturbances in terrestrial magnetism 
 which it would be impossible to acquire from eye-observa- 
 tion.' Amongst the General Remarks of the Report it is 
 stated that ' There are two points which have distinctly 
 engaged my attention. The first of these is, the introduction 
 of the American method of observing transits, by completing 
 a galvanic circuit by means of a touch of the finger at the 
 instant of appulse of the transiting body to the wire of the 
 instrument, which circuit will then animate a magnet that 
 will make an impression upon a moving paper. After careful 
 consideration of this method, I am inclined to believe that, in 
 Prof. Mitchell's form, it does possess the advantages which 
 have been ascribed to it, and that it may possess peculiar 
 advantages in this Observatory, where the time-connection of 
 transits made with two different instruments (the Transit and 
 the Altazimuth) is of the highest importance.... The second 
 point is, the connection of the Observatory with the galvanic 
 telegraph of the South Eastern Railway, and with other lines 
 of galvanic wire with which that telegraph communicates. I 
 had formerly in mind only the connection of this Observatory 
 
204 GEORGE BIDDELL AIRY. 
 
 with different parts of the great British island : but I now 
 think it possible that our communications may be extended 
 far beyond its shores. The promoters of the submarine tele- 
 graph are very confident of the practicability of completing a 
 galvanic connection between England and France : and I 
 now begin to think it more than possible that, within a few 
 years, observations at Paris and Brussels may be registered 
 on the recording surfaces at Greenwich, and vice versa.' 
 Prof. Hansen was engaged in forming Lunar Tables from his 
 Lunar Theory, but was stopped for want of money. On 
 Mar. /th I represented this privately to Mr Baring, First 
 Lord of the Admiralty ; and on Mar. 3Oth I wrote officially 
 to the Admiralty, soliciting 150 with the prospect, if neces- 
 sary, of making it 200. On Apr. loth the Admiralty gave 
 their assent. The existence of Hansen's Lunar Tables is due 
 to this grant. The King of Denmark's Medal for Comets 
 was discontinued, owing to the difficulties produced by the 
 hostility of Prussia. On Aug. ist I gave to the Treasury my 
 opinion on the first proposal for a large reflector in Australia : 
 it was not strongly favourable. In August, being (with my 
 wife and Otto Struve) on a visit to Lady Breadalbane at 
 Taymouth Castle, I examined the mountain Schehallien. 
 As in other years, I reported on several Papers for the Royal 
 Society, and took part in various business for them. In the 
 Royal Astronomical Society I had much official business, as 
 President. In March I communicated to the Athenaeum my 
 views on the Exodus of the Israelites : this brought me into 
 correspondence with Miss Corbaux, Robert Stephenson, 
 Capt. Vetch, and Prof. J. D. Forbes. In December I went 
 to the London Custom House, to see Sir T. Freemantle 
 (Chairman of Customs), and to see how far decimal sub- 
 divisions were used in the Custom House." 
 
 Of private history: "From Mar. iQth to 22nd I was on 
 an expedition to Folkestone, Dover, Dungeness, &c. From 
 Apr. 3rd to 8th at Playford, and again for short periods in 
 June and July. From Aug. ist to Sept 5th I was travelling 
 
AT GREENWICH OBSERVATORY 1846 TO 1856. 2O5 
 
 in Scotland with my wife and Otto Struve (for part of the 
 time). At Edinburgh I attended the Meeting of the British 
 Association, and spoke a little in Section A. I was nomi- 
 nated President for 1851 at Ipswich. We travelled to Cape 
 Wrath and returned by Inverness and the Caledonian Canal. 
 I was at Play ford for a short time in October and Decem- 
 ber." 
 
 1851 
 
 " In this year the great shed was built (first erected on the 
 Magnetic Ground, and about the year 1868 transferred to the 
 South Ground). The chronometers were taken from the old 
 Chronometer Room (a room on the upper story fronting the 
 south, now, 1872, called Library 2) and were put in the room 
 above the Computing Room (where they remained for 10 or 
 12 years, I think) : it had a chronometer-oven with gas-heat, 
 erected in 1850. The following passage is quoted from the 
 Report to the Visitors : ' As regards Meridional Astronomy 
 our equipment may now be considered complete. As I have 
 stated above, an improvement might yet be made in our 
 Transit Circle ; nevertheless I do not hesitate to express my 
 belief that no other existing meridional instrument can be 
 compared with it. This presumed excellence has not been 
 obtained without much thought on my part and much anxiety 
 on the part of the constructors of the instrument (Messrs 
 Ransomes and May, and Mr Simms). But it would be very 
 unjust to omit the further statement that the expense of the 
 construction has considerably exceeded the original estimate, 
 and that this excess has been most liberally defrayed by the 
 Government.' In December Sir John Herschel gave his 
 opinion (to the Admiralty, I believe) in favour of procuring 
 for the Cape Observatory a Transit Circle similar to that at 
 Greenwich. I had much correspondence about sending Pierce 
 Morton (formerly a pupil of mine at Cambridge, a clever 
 gentlemanly man, and a high wrangler, but somewhat flighty) 
 
206 GEORGE BIDDELL AIRY. 
 
 as Magnetic Assistant to the Cape Observatory : he was with 
 me from May to October, and arrived at the Cape on 
 Nov. 27th. I was much engaged with the clock with conical 
 motion of pendulum, for 'uniforrrf movement of the Chrono- 
 graphic Barrel. Regarding galvanic communications : On 
 Sept. iQth I had prepared a Draft of Agreement with the 
 South Eastern Railway Company, to which they agreed. In 
 November I wrote to Sir T. Baring (First Lord of the Ad- 
 miralty) and to the Admiralty for sanction, which was given 
 on Dec. i8th. In December I had various communications 
 about laying wires through the Park, &c., &c., and correspon- 
 dence about the possibility of using sympathetic clocks : in 
 June, apparently, I had seen Shepherd's sympathetic clock at 
 the Great Exhibition, and had seen the system of sympathetic 
 clocks at Pawson's, St Paul's Churchyard. In the last quarter 
 of this year I was engaged in a series of calculations of chrono- 
 logical eclipses. On Sept. 3<Dth Mr Bosanquet wrote to me 
 about the Eclipse of Thales, and I urged on the computations 
 related to it, through Mr Breen. In October the eclipse of 
 Agathocles (the critical eclipse for the motion of the Moon's 
 node) was going on. In October Hansteen referred me to 
 the darkness at Stiklastad. I went to Sweden to observe the 
 total eclipse of July 28th, having received assistance from the 
 Admiralty for the journeys of myself, Mr Dunkin, Mr Hum- 
 phreys and his friend, and Capt. Blackwood. I had prepared 
 a map of its track, in which an important error of the Berliner 
 Jahrbuch (arising from neglect of the earth's oblateness) was 
 corrected. I gave a lecture at the Royal Institution, in 
 preparation for the eclipse, and drew up suggestions for 
 observations, and I prepared a scheme of observations for 
 Greenwich, but the weather was bad. The official account 
 of the Observations of the Eclipse, with diagrams and con- 
 clusions, is given in full in a paper published in the Royal 
 Astr. Society's Memoirs. This year I was President of the 
 British Association, at the Ipswich Meeting : it necessarily 
 produced a great deal of business. I lectured one evening 
 
AT GREENWICH OBSERVATORY 1846 TO 1856. 2O/ 
 
 on the coming eclipse. Prince Albert was present, as guest 
 of Sir William Middleton : I was engaged to meet him at 
 dinner, but when I found that the dinner day was one of the 
 principal soiree days, I broke off the engagement. On May 
 26th I had the first letter from E. Hamilton (whom I had 
 known at Cambridge) regarding the selection of professors 
 for the University of Sydney. Herschel, Maldon, and H. 
 Denison were named as my coadjutors. Plenty of work was 
 done, but it was not finished till 1852. In connection with 
 the clock for Westminster Palace, in February there were 
 considerations about providing other clocks for the various 
 buildings ; and this probably was one reason for my examining 
 Shepherd's Clocks at the Great Exhibition and at Pawson's. 
 In November I first proposed that Mr E. B. Denison should 
 be associated with me. About the end of the year, the 
 plan of the tower was supplied to me, with reference to the 
 suspension of the weights and other particulars. In 1850 
 Admiral Dundas (M.P. for Greenwich and one of the Board 
 of Admiralty) had requested me to aid the Trustees of the 
 Dee Navigation against an attack; and on Mar. iQth 1851 I 
 went to Chester to see the state of the river. On Jan. 1st 
 1852 I went to give evidence at the Official Enquiry. At a 
 discussion on the construction of the Great Exhibition build- 
 ing in the Institution of Civil Engineers, I expressed myself 
 strongly on the faulty principles of its construction. In this 
 year I wrote my first Paper on the landing of Julius Csesar in 
 Britain, and was engaged in investigations of the geography, 
 tides, sands, &c., relating to the subject." 
 
 Of private history : " I was several times at Playford during 
 January, and went there again on Dec. 23rd. In this year a 
 very heavy misfortune fell on us. My daughter, Elizabeth, 
 had been on a visit to Lady Herschel at Hawkhurst, and on 
 Apr. 2nd Sir J. Herschel wrote to me, saying that she was so 
 well in health. She returned a few days later, and from her 
 appearance I was sure that she was suffering under deadly 
 disease. After some time, an able physician was consulted, 
 
208 GEORGE BIDDELL AIRY. 
 
 who at once pronounced it to be pulmonary. A sea voyage 
 was thought desirable, and my wife took her to Shetland, 
 where there was again a kind welcome from Mr Edmonston. 
 But this, and the care taken on her return, availed nothing : 
 and it was determined to take her to Madeira. My wife and 
 daughter sailed in the brig ' Eclipse ' from Southampton on 
 Dec. nth. The termination came in 1852. Oh Nov. 23rd I 
 went to Bradfield, near Bury : my uncle, George Biddell, died, 
 and I attended the funeral on Nov. 29th. From July i8th to 
 Aug. 24th I was in Sweden for the Observation of the 
 Eclipse, and returned through Holland. In October I was 
 about a week at Ventnor and Torquay, and from Dec. 7th 
 to nth at Southampton, on matters connected with my 
 daughter's illness." 
 
 The following extracts are from letters to his wife, relating 
 to the Observation of the eclipse, his interview with the King 
 of Sweden, &c., and his visit to the pumping engines at 
 Haarlem : 
 
 July 28, half-past 10, morning. 
 
 The weather is at present most perfectly doubtful. Nearly the 
 whole sky is closely covered, yet there is now and then a momentary 
 gleam of sun. The chances are greatly against much of the eclipse 
 being seen. All is arranged to carry off the telescope, &c., at 1 1 : 
 they can be carted to the foot of the hill, and we have made out a 
 walking-pass then to the top. We are to dine with Mr Dickson 
 afterwards. 
 
 July 28, 10 at night. 
 
 Well we have had a glorious day. As soon as we started, the 
 weather began to look better. We went up the hill and planted my 
 telescope, and the sky shewed a large proportion of blue. At first I 
 placed the telescope on the highest rock, but the wind blew almost 
 a gale, and shook it slightly : so I descended about 8 feet to one 
 side. (The power of doing this was one of the elements in my 
 choice of this station, which made me prefer it to the high hill 
 beyond the river.) The view of scenery was inexpressibly beautiful. 
 
AT GREENWICH OBSERVATORY 1846 TO 1856. 2OQ 
 
 The beginning of eclipse was well seen. The sky gradually thickened 
 from that time, so that the sun was in whitish cloud at the totality, 
 and barely visible in dense cloud at the end of the eclipse. The 
 progress of the eclipse brought on the wonderful changes that you 
 know : just before the totality I saw a large piece of blue sky become 
 pitch black ; the horror of totality was very great ; and then flashed 
 into existence (I do not know how) a broad irregular corona with 
 red flames instantly seen of the most fantastic kind. The darkness 
 was such that my assistant had very great trouble in reading his box 
 chronometer. (A free-hand explanatory diagram is here given.) 
 Some important points are made out from this, ist the red flames 
 certainly belong to the sun. 2nd they certainly are in some instances 
 detached. 3rd they are sometimes quite crooked. 4th they seem 
 to be connected with spots. The corona was brilliant white. One 
 star brilliant : I believe Venus. I had no time to make observations 
 of polarization, &c., although prepared. When the totality was more 
 than half over I looked to N. and N.W., and in these regions there 
 was the fullest rosy day-break light. After the sun-light reappeared, 
 the black shadow went travelling away to the S.E. exactly like the 
 thunder-storm from the Main. The day then grew worse, and we 
 came home here (after dinner) in pouring rain. 
 
 STOCKHOLM, 
 
 1851, Aug. 5- 
 
 I then by appointment with Sir Edmund Lyons went with him to 
 the Minister for Foreign Affairs, Baron Stjerneld, who received me 
 most civilly. My business was to thank him for the orders which 
 had been given to facilitate the landing of our telescopes, &c., &c. 
 He was quite familiar with the names of my party, Humphreys 
 Milaud, &c., so that I trust they have been well received (I have 
 had no letter). He intimated, I suppose at Sir E. Lyons's suggestion, 
 that perhaps King Oscar might wish to see me, but that it would 
 not be on Tuesday. So I replied that I was infinitely flattered and 
 he said that he would send a message to Sir E. Lyons by Tuesday 
 evening. Now all this put me in a quandary : because I wanted to 
 see Upsala, 47 miles off : and the steamboats on the Malar only go 
 in the morning and return in the morning : and this was irreconcile- 
 able with waiting for his Majesty's appointment which might be for 
 Wednesday morning. So after consultation Sir E. Lyons put me in 
 the hands of a sort of courier attached to the Embassy, and he pro- 
 A. B. 14 
 
210 GEORGE BIDDELL AIRY. 
 
 cured a caleche, and I posted to Upsala yesterday afternoon (knock- 
 ing the people up at n at night) and posted back this afternoon. 
 And sure enough a message has come that the king expects me at 
 ii to-morrow morning. -Posting of course is much dearer than 
 steam-boat travelling, but it is cheap in comparison with England : 
 two horses cost is. for nearly 7 miles. At Upsala there is a very 
 good old cathedral, I suppose the only one in Sweden : and many 
 things about the University which interested me. I sent my card to 
 Professor Fries, and he entirely devoted himself to me : but imagine 
 our conversation he spoke in Latin and I in French : however we 
 understood each other very well. It is on the whole a dreary 
 country except where enlivened by lakes : some parts are pine forests 
 and birch forests, but others are featureless ground with boulder 
 stones, like the worst part of the Highlands. 
 
 August 6, Wednesday, 3 o'clock. 
 
 I rigged myself in black trowsers and white waistcoat and neck- 
 cloth this morning. Sir Edmund Lyons called. Baron Wrede called 
 on me : he had observed the Eclipse at Calmar and brought his 
 drawing, much like mine. He conducted me to the Palace. The 
 Minister for Foreign Affairs came to me. In the waiting-room I was 
 introduced to the Lieutenant-Governor of Christianstad, who had had 
 the charge of Humphreys and Milaud. He had placed a guard of 
 soldiers round them while they were observing. They saw the 
 eclipse well. Captain Blackwood went to Helsingborg instead of 
 Bornholm, and saw well. I am sorry to hear that it was cloudy at 
 Christiania, Mr Dunkin's station. I heard some days ago that Hind 
 had lost his telescope, but I now heard a very different story : that 
 he landed at Ystad, and found a very bad hotel there : that he learnt 
 from Murray that the hotels at Carlscrona (or wherever he meant to 
 go) were much worse ; and so he grew faint at heart and turned back. 
 I was summoned in to the King and presented by the Minister 
 (Stjerneld), and had a long conversation with him : on the eclipse, 
 the arc of meridian, the languages, and the Universities. We spoke 
 in French. Then Baron Wrede went with me to the Rittershus 
 (House of Lords or Nobles) in Session, and to the Gallery ot 
 Scandinavian Antiquities, which is very remarkable : the collection 
 of stone axes and chisels, bronze do., iron do., ornaments, &c. is 
 quite amazing. I was struck with seeing specimens from a very 
 
AT GREENWICH OBSERVATORY 1846 TO 1856. 211 
 
 distant age of the Maid of Norway's brooch : the use of which I 
 explained to the Director. 
 
 I dined and drove out with Sir E. Lyons, and called at the 
 houses of the Baron Stjerneld and of the Norwegian Minister Baron 
 Due, and had tea at the latter. Most of these people speak English 
 well, and they seem to live in a very domestic family style. I should 
 soon be quite at home here: for I perceive that my reception at 
 Court, &c., make people think that I am a very proper sort of 
 person. 
 
 The extract concerning his visit to the Pumping-Engines 
 at Haarlem is as follows : 
 
 LEYDEN, 
 1851, August 20, Wednesday. 
 
 I went to see the great North Holland Canal, and went a mile 
 or two in a horse-drawn-boat upon it : a very comfortable convey- 
 ance. Saw windmills used for sawing timber and other purposes, as 
 well as some for grinding and many for draining. Yesterday at half- 
 past one I went by railway to Haarlem. I did not look at anything 
 in the town except going through it and seeing that it is a curious 
 fantastic place, but I drove at once to the burgomaster to ask per- 
 mission to visit one of the three great pumping engines for draining 
 the immense Haarlem lake, and then drove to it. Imagine a round 
 tower with a steam-cylinder in its center; and the piston which 
 works up-and-down, instead of working one great beam as they 
 usually do, works eight, poking out on different sides of the round 
 tower, and each driving a pump 6 feet in diameter. I am glad to 
 have seen it. Then by railway here. 
 
 1852 
 
 " Galvanic communication was now established with 
 Lewisham station (thus giving power of communicating with 
 London, Deal, &c.). From the Report to the Board of 
 Visitors it appears that, in the case of the Transit Circle, 
 the azimuth of the Instrument as determined by opposite 
 
 142 
 
212 GEORGE BIDDELL AIRY. 
 
 passages of the Pole Star had varied four seconds; and in 
 the case of the Altazimuth, there was a discordance in the 
 azimuthal zeros of the Instrument, as determined from obser- 
 vations of stars. In both cases it was concluded that the 
 discordances arose from small movements of the ground. 
 Under the head of 'General Remarks' in the Report, the 
 following paragraph occurs : * It will be perceived that the 
 number of equatoreal observations made here at present is 
 small : and that they are rarely directed to new comets and 
 similar objects which sometimes excite considerable interest. 
 This omission is intentional. It is not because the instru- 
 mental means are wanting (for our Equatoreals, though not 
 comparable to those of either Cambridge, or of Pulkowa, are 
 fully equal to those usually directed to such objects), but it 
 is because these observations are most abundantly supplied 
 from other observatories, public and private, and because the 
 gain to those observations from our taking a part in them 
 would, probably, be far less than the loss to the important 
 class of observations which we can otherwise follow so well. 
 Moreover, I am unwilling to take any step which could be 
 interpreted as attempting to deprive the local and private 
 observatories of honours which they have so nobly earned. 
 And, finally, in this act of abstinence, I am desirous of giving 
 an example of adhesion to one principle which, I am con- 
 fident, might be extensively followed with great advantage 
 to astronomy : the principle of division of labour.' Dis- 
 coveries of small planets were now not infrequent : but the 
 only one of interest to me is Melpomene, for the following 
 reason. On 1852 June 24 I lost my most dear, amiable, 
 clever daughter Elizabeth : she died at Southampton, two 
 days after landing from Madeira. On that evening Mr Hind 
 discovered the planet ; and he requested me to give a name. 
 I remembered Horace's ' Praecipe lugubres cantus, Mel- 
 pomene,' and Cowley's ' I called the buskin'd muse Mel- 
 pomene and told her what sad story I would write,' and 
 suggested Melpomene, or Penthos : Melpomene was adopted. 
 
AT GREENWICH OBSERVATORY 1846 TO 1856. 213 
 
 The first move about the Deal Time Ball was in a letter 
 from Commander Baldock to the Admiralty, suggesting that 
 a Time Ball, dropped by galvanic current from Greenwich, 
 should be attached to one of the South Foreland Lighthouses. 
 The Admiralty sent this for my Report. I went to the place, 
 and I suggested in reply (Nov. 15th) that a better place 
 would be at an old signal station on the chalk downs. The 
 decisive change from this was made in 1853. As the result 
 of my examination and enquiries into the subject of sym- 
 pathetic clocks, I established 8 sympathetic clocks in the 
 Royal Observatory, one of which outside the entrance gate 
 had a large dial with Shepherd's name as Patentee. Ex- 
 ception was taken to this by the solicitor of a Mr Bain who 
 had busied himself about galvanic clocks. After much cor- 
 respondence I agreed to remove Shepherd's name till Bain 
 had legally established his claim. This however was never 
 done: and in 1853 Shepherd's name was restored. In Nov. 
 1851, Denison had consented to join me in the preparation 
 of the Westminster Clock. In Feb. 1852 we began to have 
 little disagreements. However on Apr. 6th I was going to 
 Madeira, and requested him to act with full powers from me. 
 I communicated to the Royal Society my Paper on the 
 Eclipses of Agathocles, Thales, and Xerxes. In the British 
 Association, I had presided at the Ipswich Meeting in 1851, 
 and according to custom I ought to attend at the 1852 
 Meeting (held at Belfast) to resign my office. But I was 
 broken in spirit by the death of my daughter, and the thing 
 generally was beyond my willing enterprise. I requested 
 Sir Roderick Murchison to act generally for me: which he 
 did, as I understood, very gracefully. In this year a proposal 
 was made by the Government for shifting all the Meeting 
 Rooms of the Scientific Societies to Kensington Gore, which 
 was stoutly resisted by all, and was finally abandoned." 
 
 Of private history : " I was at Playford in January, and 
 went thence to Chester on the enquiry about the tides of 
 the Dee; and made excursions to Halton Castle and to 
 
214 GEORGE BIDDELL AIRY. 
 
 Holyhead. From Apr. 8th to May I4th I was on the 
 voyage to and from Madeira, and on a short visit to my wife 
 and daughter there. On June 23rd I went to Southampton 
 to meet my wife and daughter just landed from Madeira : on 
 June 24th my dear daughter Elizabeth died : she was buried 
 at Playford on June 29th. I was at Playford also in July 
 and December. From Sept. i6th to 24th I went to Cumber- 
 land, via Fleetwood and Peel." 
 
 1853 
 
 "On May 3rd 1853 I issued an address to the individual 
 Members of the Board of Visitors, proposing the extension of 
 the Lunar Reductions from 1830. From this it appears that 
 'Through the whole period (from 1830 to 1853), tne places of 
 the Moon, deduced from the observations, are compared with 
 the places computed in the Nautical Almanac : that is, with 
 Burckhardt's tables, which have been used for many years in 
 
 computing the places of the Nautical Almanac Very 
 
 lately, however, Mr Adams has shewn that Burckhardt's 
 Parallax is erroneous in formula and is numerically incorrect, 
 sometimes to the amount of seven seconds. In consequence 
 of this, every reduction of the Observations of the Moon, 
 from 1830 to the present time, is sensibly erroneous. And 
 the error is of such a nature that it is not easy, in general, to 
 introduce its correction by any simple process.... The number 
 of observations to the end of 1851 (after which time the 
 parallax will be corrected in the current reductions) is about 
 2560. An expense approaching to 400 might be incurred 
 in their reduction.' Subsequently I made application to the 
 Admiralty, and the ^"400 was granted on Dec. I2th. In the 
 Report to the Visitors it is stated that with regard to the 
 Transit Circle, changes are under contemplation in its re- 
 flection-apparatus : one of these changes relates to the ma- 
 terial of the trough. ' Several years ago, when I was at 
 Hamburgh, my revered friend Prof. Schumacher exhibited to 
 
AT GREENWICH OBSERVATORY 1846 TO 1856. 215 
 
 me the pacifying effect of a copper dish whose surface had 
 
 been previously amalgamated with quicksilver The Rev. 
 
 Charles Pritchard has lately given much attention to this 
 curious property of the metals, and has brought the practical 
 operation of amalgamation to great perfection. Still it is 
 not without difficulty, on account of a singular crystallization 
 of the amalgam.' With regard to the Chronograph, the 
 Report states : ' The Barrel Apparatus for the American 
 
 method of observing transits is not yet brought into use I 
 
 have, however, brought it to such a state that I am beginning 
 to try whether the Barrel moves with sufficient uniformity to 
 be itself used as the Transit Clock. This, if perfectly se- 
 cured, would be a very great convenience, but I am not very 
 sanguine on that point.' A change had been made in the 
 Electrometer-apparatus : ' A wire for the collection of atmo- 
 spheric electricity is now stretched from a chimney on the 
 north-west angle of the leads of the Octagon Room to the 
 Electrometer pole.... There appears to be no doubt that a 
 greater amount of electricity is collected by this apparatus 
 than by that formerly in use.' As regards the Magnetical 
 Observations : ' The Visitors at their last Meeting, expressed 
 a wish that some attempt should be made to proceed further 
 in the reduction or digest of the magnetical results, if any 
 satisfactory plan could be devised. I cannot say that I have 
 yet satisfied myself on the propriety of any special plan 
 that I have examined....! must, however, confess that, in 
 viewing the capricious forms of the photographic curves, my 
 mind is entirely bewildered, and I sometimes doubt the 
 possibility of extracting from them anything whatever which 
 can be considered trustworthy.' Great progress had been 
 made with the distribution of time. 'The same Normal 
 Clock maintains in sympathetic movement the large clock at 
 the entrance gate, two other clocks in the Observatory, and a 
 clock at the London Bridge Terminus of the South-Eastern 
 Railway.... It sends galvanic signals every day along all the 
 principal railways diverging from London. It drops the 
 
2l6 GEORGE BUJDELL AIRY. 
 
 Greenwich Ball, and the Ball on the Offices of the Electric 
 Telegraph Company in the Strand;... All these various effects 
 are produced without sensible error of time; and I cannot 
 but feel a satisfaction in thinking^that the Royal Observatory 
 is thus quietly contributing to the punctuality of business 
 through a large portion of this busy country. I have the 
 satisfaction of stating to the Visitors that the Lords Com- 
 missioners of the Admiralty have decided on the erection of 
 a Time-Signal Ball at Deal, for the use of the shipping in the 
 Downs, to be dropped every day by a galvanic current from 
 the Royal Observatory. The construction of the apparatus 
 is entrusted to me. Probably there is no roadstead in the 
 world in which the knowledge of true time is so important.' 
 The Report includes an account of the determination of 
 the Longitude of Cambridge Observatory by means of gal- 
 vanic signals, which appear to have been perfectly successful. 
 Under the head of General Remarks the following passage 
 appears : ' The system of combining the labour of unattached 
 computers with that of attached Assistants tends materially 
 to strengthen our powers in everything relating to computa- 
 tion. We find also, among the young persons who are 
 engaged merely to serve as computers, a most laudable 
 ambition to distinguish themselves as observers ; and thus 
 we are always prepared to undertake any observations which 
 may be required, although necessarily by an expenditure of 
 strength which would usually be employed on some other 
 work.' Considerable work was undertaken in preparing a 
 new set of maps of our buildings and grounds. On Apr. 23rd 
 there was a small fire in the magnetic observatory, which did 
 little mischief. In December I wrote my description of the 
 Transit Circle. Lieut. Stratford, the Editor of the Nautical 
 Almanac, died, and there was some competition for the office. 
 I was willing to take it at a low rate, for the addition to my 
 salary: Mr Main and I think Mr Glaisher were desirous 
 of exchanging to it : Prof. Adams was anxious for it. The 
 Admiralty made the excellent choice of Mr Hind. In 
 
AT GREENWICH OBSERVATORY 1846 TO 1856. 2i; 
 
 October Faraday and I, at Lothbury, witnessed some re- 
 markable experiments by Mr Latimer Clark on a galvanic 
 current carried four times to and from Manchester by sub- 
 terranean wires (more than 2000 miles) shewing the retarda- 
 tion of visible currents (at their maximum effect) and the 
 concentration of active power. I made investigations of the 
 velocity of the Galvanic Current. I was engaged on the 
 preliminary enquiries and arrangements for the Deal Time 
 Ball. With respect to the Westminster Clock ; an angry 
 paper was issued by Mr Vulliamy. In October I expostu- 
 lated with Denison about his conduct towards Sir Charles 
 Barry: on November 7th I resigned. On Feb. nth I was 
 elected President of the Royal Astronomical Society. In 
 the Royal Institution I lectured on the Ancient Eclipses. 
 On Dec. I5th I was elected to the Academy of Brussels. 
 After preliminary correspondence with Sir W. Molesworth 
 (First Commissioner of Works, &c.) and Sir Charles Barry 
 (Architect of the Westminster Palace), I wrote, on May I4th, 
 to Mr Gladstone about depositing the four Parliamentary 
 Copies of Standards, at the Royal Observatory, the Royal 
 Mint, the Royal Society, and within a wall of Westminster 
 Palace. Mr Gladstone assented on June 23rd. On Mar. 
 26th I wrote to Mr Gladstone, proposing to take advantage 
 of the new copper coinage for introducing the decimal 
 system. I was always strenuous about preserving the 
 Pound Sterling. On May loth I attended the Committee 
 of the House of Commons on decimal coinage : and in May 
 and September I wrote letters to the Athenaeum on decimal 
 coinage. I had always something on hand about Tides. A 
 special subject now was, the cry about intercepting the tidal 
 waters of the Tyne by the formation of the Jarrow Docks, in 
 Jarrow Slake ; which fear I considered to be ridiculous." 
 
 Of private history: "From Jan. i5th to 24th I was at 
 Playford. On Mar. 4th I went to Dover to try time-signals. 
 From June 24th to Aug. 6th I was at Little Braithwaite 
 near Keswick, where I had hired a house, and made expedi- 
 
2l8 GEORGE BIDDELL AIRY. 
 
 tions with members of my family in all directions. On July 
 28th I went, with my son Wilfrid, by Workington and Mary- 
 port to Rose Castle, the residence of Bishop Percy (the 
 Bishop of Carlisle), and on to Carlisle and Newcastle, looking 
 at various works, mines, &c. On Dec. 24th I went to 
 Playford." 
 
 1854 
 
 The chronograph Barrel- Apparatus for the American 
 method of transits had been practically brought into use : 
 " I have only to add that this apparatus is now generally 
 efficient. It is troublesome in use ; consuming much time in 
 the galvanic preparations, the preparation of the paper, and 
 the translation of the puncture-indications into figures. But 
 among the observers who use it there is but one opinion on 
 its astronomical merits that, in freedom from personal 
 equation and in general accuracy, it is very far superior to 
 the observations by eye and ear." The printing and pub- 
 lication of the Observations, which was always regarded by 
 Airy as a matter of the first importance, had fallen into 
 arrear : " I stated in my last Report that the printing of 
 the Observations for 1852 was scarcely commenced at the 
 time of the last meeting of the Visitors. For a long time the 
 printing went on so slowly that I almost despaired of ever 
 again seeing the Observations in a creditable state. After a 
 most harassing correspondence, the printers were at length 
 
 persuaded to move more actively, but the volume is 
 
 still very much behind its usual time of publication." The 
 Deal Time-Ball has now been erected by Messrs Maudslays 
 and Field, and is an admirable specimen of the workmanship 
 of those celebrated engineers. The galvanic connection with 
 the Royal Observatory (through the telegraph wires of the 
 South Eastern Railway) is perfect. The automatic changes 
 of wire-communications are so arranged that, when the Ball 
 at Deal has dropped to its lowest point, it sends a message to 
 
AT GREENWICH OBSERVATORY 1846 TO 1856. 2IQ 
 
 Greenwich to acquaint me, not with the time of the beginning 
 of its fall (which cannot be in error) but with the fact that it 
 has really fallen. The Ball has several times been dropped 
 experimentally with perfect success ; and some small official 
 and subsidiary arrangements alone are wanting for bringing 
 it into constant use." The operations for the galvanic deter- 
 mination of the longitude of Brussels are described, with the 
 following conclusion : " Thus, about 3000 effective signals 
 were made, but only 1000 of these were admissible for the 
 fundamental objects of the operation. The result, I need 
 scarcely remark, claims a degree of accuracy to which no 
 preceding determination of longitude could ever pretend. I 
 apprehend that the probable error in the difference of time 
 corresponds to not more than one or two yards upon the 
 Earth's surface. A careful scheme had been arranged for the 
 determination of the longitude of Lerwick, but ' unfortu- 
 nately, the demand for chronometers caused by our large 
 naval armament has been so considerable that I cannot 
 reckon on having at my disposal a sufficient number to carry 
 on this operation successfully ; and I have, therefore, un- 
 willingly deferred it to a more peaceful time.' The covering 
 stone of Halley's Tomb in Lee Churchyard was much 
 shattered, and I applied to the Admiralty for funds for its 
 complete restoration : these were granted on Feb. 3rd. In 
 this year, under my cognizance, ;ioo was added to the 
 Hansen grant. I had much correspondence and work in 
 connection with the printing of Maclear's work at the Cape 
 of Good Hope. In June, all accounts, &c. about the Transit 
 Circle were closed at the Admiralty, and the instrument was 
 completely mounted at the Cape. Dr Scoresby (who in his 
 own way was very imperious) had attacked my methods of 
 correcting the compass in iron ships : I replied in a letter to 
 the Athenaeum on Oct. i/th. I made enquiries about opera- 
 tions for determining the longitude of Vienna, but was utterly 
 repelled by the foreign telegraph offices. In the Royal 
 Astronomical Society ; I prepared the Address on presenting 
 
220 GEORGE BIDDELL AIRY. 
 
 the Medal to Riimker. In Melbourne University: The first 
 letter received was from the Chancellor of the University 
 dated Jan. 26th, requesting that Sir John Herschel, Prof. 
 Maiden, Mr Lowe (subsequently Chancellor of the Ex- 
 chequer), and I would select professors. We had a great 
 deal of correspondence, meetings, examination of testimonials, 
 &c., and on August I4th we agreed on Wilson, Rowe, McCoy, 
 and Hearn. On Feb. i/th I received the Prussian Order of 
 Merit. I had correspondence with the Treasury on the scale 
 to be adopted for the Maps of the British Survey. I proposed 
 3^0, and for some purposes -^fa. I printed a Paper on the 
 Deluge, in which I shewed (I believe to certainty) that the 
 Deluge of Genesis was merely a Destructive Flood of the 
 Nile. Being well acquainted with the mountains of Cumber- 
 land, I had remarked that a ' man ' or cairn of stones erected 
 by the Ordnance Surveyors on the Great Gable had covered 
 up a curious natural stone trough, known as one of the 
 remarkable singularities of the country. This year, without 
 giving any notice to the Ordnance Surveyors, I sent two 
 wallers from Borrowdale to the mountain top, to remove the 
 'man' about 10 feet and expose the trough. Sir Henry 
 James afterwards approved of my act, and refunded the 
 expense. I investigated the optical condition of an eye with 
 conical cornea. 
 
 " The Harton Colliery Experiment : I had long wished to 
 repeat the experiment which I had attempted unsuccessfully 
 in 1826 and 1828, of determining by pendulum-vibrations the 
 measure of gravity at the bottom of a mine. Residing near 
 Keswick this summer, and having the matter in my mind, I 
 availed myself of an introduction from Dr Leitch to some 
 gentlemen at South Shields, for inspection of the Harton 
 Colliery. .1 judged that it would answer pretty well. I find 
 that on Aug. nth I wrote to Mr Anderson (lessee of the 
 mine), and on the same day to the Admiralty requesting 
 authority to employ a Greenwich Assistant, and requesting 
 ;ioo for part payment of expenses. On August i6th the 
 
AT GREENWICH OBSERVATORY 1846 TO 1856. 221 
 
 Admiralty assent. There were many preparations to be 
 made, both personal and instrumental. My party con- 
 sisted of Dunkin (Superintendant), Ellis, Criswick, Simmons, 
 Pogson, and Riimker: I did not myself attend the detail of 
 observations. The observations began on Oct. 2nd and 
 ended on Oct. 2ist: supplementary observations were sub- 
 sequently made at Greenwich for examining the coefficient 
 of temperature-correction. On Oct. 24th I gave a Lecture 
 at South Shields on the whole operation. In ' Punch ' of 
 Nov. 1 8th there was an excellent semi-comic account of the 
 experiment, which as I afterwards found was written by Mr 
 Percival Leigh." 
 
 Of private history : "On Jan. i8th I returned from Play- 
 ford. From Mar. loth to I3th I was at Deal, and visited Sir 
 John Herschel at Hawkhurst. From June 28th to Aug. 7th 
 I was staying with my family at The Grange, in Borrowdale 
 near Keswick : and also made an expedition to Penrith, 
 Carlisle, Newcastle, Jarrow, &c. ; and descended the Harton 
 Pit. In September and also in October I was at South 
 Shields on the Harton Experiments. From Dec. I4th to i8th 
 I was at Cambridge, and on the 26th I went to Playford." 
 
 The following letter, written in answer to a lady who 
 had asked him to procure permission from Lord Rosse for 
 her to observe with his telescope, is characteristic : 
 
 ROYAL OBSERVATORY, GREENWICH. 
 
 1854, September 20. 
 
 DEAR MADAM, 
 
 The state of things with regard to Lord Rosse's Tele- 
 scope is this. If a night is fine, it is wanted for his use or for the 
 use of professional astronomers. If it is not fine, it is of no use to 
 anybody. Now considering this, and considering that the appropria- 
 tion of the telescope on a fine night to any body but a technical 
 astronomer is a misapplication of an enormous capital of money and 
 intellect which is invested in this unique instrument it is against my 
 conscience to ask Lord Rosse to place it at the service of any person 
 
222 GEORGE BIDDELL AIRY. 
 
 except an experienced astronomer. No introduction, I believe, is 
 necessary for seeing it in the day-time. The instrument stands un- 
 enclosed in the Castle Demesne, to which strangers are admitted 
 without question, I believe... .......... .^. 
 
 Faithfully yours, 
 
 G. B. AIRY. 
 
 1855 
 
 " On May Qth it was notified to me (I think through the 
 Hydrographer) that the Admiralty were not unwilling to 
 increase my salary. I made application therefore ; and on 
 Jan. 2 ist 1856 Sir Charles Wood notified to me that the 
 Admiralty consented to have it raised from ;8oo to .1000. 
 In the Report to the Board of Visitors it appears that * At 
 the instance of the Board of Trade, acting on this occasion 
 through a Committee of the Royal Society, a model of the 
 Transit Circle (with the improvement of perforated cube, &c. 
 introduced in the Cape Transit Circle) has been prepared for 
 the Great Exhibition at Paris.' Under the head of Reduc- 
 tion of Astronomical Observations it is stated that ' During 
 the whole time of which I have spoken, the galvanic-contact 
 method has been employed for transits, with the exception of 
 a few days, when the galvanic apparatus was out of order. 
 From the clock errors, I have deduced the personal equations 
 of the observers in our usual way. . . . The result is that the 
 magnitude of the personal equations in the galvanic-touch 
 method is not above half of that in the eye and ear method.' 
 With regard to the Reduction of the Magnetical Observations, 
 ' I have not yet felt sufficiently satisfied with any pro- 
 posed method of discussing the magnetic results to devote 
 any time to their further treatment.' 'The Time-Signal 
 Ball at Deal was brought into regular use at the beginning of 
 the present year. In a short time, however, its action was 
 interrupted, partly by derangement of the apparatus, and 
 partly by the severity of the weather, which froze the 
 
AT GREENWICH OBSERVATORY 1846 TO 1856. 223 
 
 sulphuric acid to the state of jelly. I sent an assistant and 
 workman to put it in order, and since that time it has 
 generally acted very well. Application has been made to 
 me from one of the important offices of Government (the 
 Post Office) for the galvanic regulation of their clocks. 
 On considering the risks to which various galvanic com- 
 munications are liable, and the financial necessity for 
 occupying wires as little as possible, I perceived that it was 
 necessary to devise constructions which should satisfy the 
 following conditions. First, that a current sent once a day 
 should suffice for adjusting the clock, even if it had gone ten 
 or more seconds wrong. Secondly, that an occasional failure 
 of the current should not stop the clock. I have arranged 
 constructions which possess these characters, and the artist 
 (Mr C. Shepherd) is now engaged in preparing estimates of 
 the expense. I think it likely that this may prove to be the 
 beginning of a very extensive system of clock regulation." 
 With respect to the operations for determining the longitude 
 of Paris, it is stated that, " The whole number of days of 
 signal transmission was eighteen, and the whole number of 
 signals transmitted was 2530. The number of days con- 
 sidered available for longitude, in consequence of transits of 
 stars having been observed at both Observatories, was twelve, 
 and the number of signals was 1703. Very great care was 
 taken on both sides, for the adjustments of the instruments. 
 The resulting difference of longitude, 9- 20-63% is probably 
 very accurate. It is less by nearly i 8 - of time than that 
 determined in 1825 by rocket-signals, under the superintend- 
 ance of Sir John Herschel and Col. Sabine. The time 
 occupied by the passage of the galvanic current appears to 
 be T ^th of a second." With regard to the Pendulum Experi- 
 ments in the Harton Colliery, after mentioning that personal 
 assistance had been sought and obtained from the Observa- 
 tories of Cambridge, Oxford, Durham, and Red Hill, the 
 Report states that " The experiments appear to have been in 
 every point successful, shewing beyond doubt that gravity is 
 
224 GEORGE BIDDELL AIRY. 
 
 increased at the depth of 1260 feet by r^o^th part. I trust 
 that this combination may prove a valuable precedent for 
 future associations of the different Observatories of the 
 kingdom, when objects requiring extensive personal or- 
 ganization shall present themselves." On Oct. i8th the 
 Astronomer Royal printed an Address to the Individual 
 Members of the Board of Visitors on the subject of a large 
 new Equatoreal for the Observatory. After a brief statement 
 of the existing equipment of the Observatory in respect of 
 equatoreal instruments, the Address continues thus : " It is 
 known to the Visitors that I have uniformly objected to any 
 luxury of extrameridional apparatus, which would materially 
 divert us from a steady adherence to the meridional system 
 which both reason and tradition have engrafted on this 
 Observatory. But I feel that our present instruments are 
 insufficient even for my wishes ; and I cannot overlook the 
 consideration that due provision must be made for future 
 interests, and that we are nearer by twenty years to the time 
 when another judgment must decide on the direction which 
 shall be given to the force of the Observatory." " In August 
 I had some correspondence about the Egyptian wooden 
 astronomical tablets with Mr Gresswell and others : they 
 were fully examined by Mr Ellis. In this year I was much 
 engaged on schemes for compasses, and in June I sent my 
 Paper on Discussions of Ships' Magnetism to the Royal 
 Society. On Dec. 6th the mast of the Observatory time-ball 
 broke, and the Ball fell in the Front Court. On Aug. 4th 
 my valued friend Mr Sheepshanks died ; and on Aug. I4th I 
 went to London to see the Standard Bars as left by him. 
 Afterwards, on Oct. 25th I went to Reading to collect the 
 papers about Standards left by Mr Sheepshanks. I made a 
 mechanical construction for Euclid I. 47, with which I was 
 well satisfied. On Apr. I3th I joined a deputation to the 
 Chancellor of the Exchequer (Sir G. Cornewall Lewis) on 
 Decimal Coinage." 
 
 Of private history : " I was at Playford for a large part of 
 
AT GREENWICH OBSERVATORY 1846 TO 1856. 22$ 
 
 January. On Mar. 26th I went to Reading, to visit Mr 
 Sheepshanks, and afterwards to Silchester and Hereford. 
 On June 2ist I went with my wife and two eldest sons to 
 Edinburgh and other places in Scotland, but residing 
 principally at Oban, where I hired a house. Amongst other 
 expeditions, I and my son Wilfrid went with the * Pharos ' 
 (Northern Lights Steamer) to the Skerry Vohr Lighthouse, 
 &c. I also visited Newcastle, &c., and returned to Green- 
 wich on Aug. 2nd. From Oct. I2th to I7th I was at 
 Cambridge. On Dec. 24th I went to Playford." 
 
 A. B. 15 
 
CHAPTER VII. 
 
 AT GREENWICH OBSERVATORY 1856 TO 1866. 
 
 1856 
 
 " IN the Report to the Visitors there is an interesting 
 account of the difficulties experienced with the Reflex Zenith 
 Tube in consequence of the tremors of the quicksilver trans- 
 mitted through the ground. Attempts were made to reduce 
 the tremor by supporting the quicksilver trough on a stage 
 founded at a depth of 10 feet below the surface, but it was 
 not in the smallest degree diminished, and the Report states 
 that 'The experience of this investigation justifies me in 
 believing that no practicable depth of trench prevents the 
 propagation of tremor when the soil is like that of Greenwich 
 Hill, a gravel, in all places very hard, and in some, cemented 
 to the consistency of rock.' With respect to the regulation 
 of the Post Office clocks, ' One of the galvanic clocks in the 
 Post Office Department, Lombard Street, is already placed 
 in connection with the Royal Observatory, and is regulated 
 at noon every day... other clocks at the General Post Office 
 are nearly prepared for the same regulation, and I expect 
 that the complete system will soon be in action.' Under the 
 head of General Remarks a careful summary is given of the 
 work of the Observatory, and the paragraph concludes as 
 follows : ' Lastly there are employments which connect the 
 scientific Observatory with the practical world ; the distribu- 
 tion of accurate time, the improvement of marine time- 
 
AT GREENWICH OBSERVATORY 1856 TO 1 866. 22/ 
 
 keepers, the observations and communications which tend to 
 the advantage of Geography and Navigation, and the study, 
 in a practical sense, of the modifications of Magnetism ; a 
 careful attention to these is likely to prove useful to the 
 world, and conducive to the material prosperity of the Ob- 
 servatory : and these ought not to be banished from our 
 system.' In September I prepared the first specification for 
 the building to carry the S.E. Dome. In September, learning 
 that Hansen's Lunar Tables were finished in manuscript, I 
 applied to Lord Clarendon and they were conveyed to me 
 through the Foreign Office : in October I submitted to the 
 Admiralty the proposal for printing the Tables, and in 
 November I learned that the Treasury had assented to the 
 expense. Lieut. Daynou's eclipses and occultations for 
 longitudes of points in South Africa, observed in 1854 and 
 1855, were calculated here in this year. On Feb. i6th I 
 made my first application to Sir C. Wood (First Lord of the 
 Admiralty) for assistance to C. Piazzi Smyth to carry out 
 the Teneriffe Experiment : grounding it in part on the 
 failure of attempts to see the solar prominences. He gave 
 encouragement, and on Mar. i8th I transmitted Piazzi Smyth's 
 Memorial to the Admiralty : on May 2nd the Admiralty 
 authorized an expense of 500. I drew up suggestions. 
 The Sheepshanks Fund : After the death of my friend 
 Richard Sheepshanks, his sister Miss Anne Sheepshanks 
 wished to bestow some funds in connection with the Uni- 
 versity of Cambridge, Trinity College, and Astronomy, to 
 which his name should be attached. There must have been 
 some conversation with me, but the first letter is one from 
 De Morgan in August. In September I had a conversation 
 with Miss Sheepshanks, and sent her my first draft of a 
 scheme, to which she assented. On Sept. 3Oth I wrote to 
 Whewell (Master of Trinity) who was much trusted by Miss 
 Sheepshanks : he consented to take part, and made some 
 suggestions. There was further correspondence, but the 
 business did not get into shape in this year. In connection 
 
 J 2 
 
228 GEORGE BIDDELL AIRY. 
 
 with the Correction of the Compass in Iron Ships : I dis- 
 cussed the observations made in the voyage of the Royal 
 Charter. On Feb. i^th I proposed to the Admiralty a 
 system of mounting the compasses with adjustable magnets, 
 and it was ordered to be tried in the Trident and Transit. 
 In February I reported to the Admiralty that the Deal Time- 
 Ball had been successful, and I proposed time-balls at Ports- 
 mouth, Plymouth, and Sheerness. There was much corre- 
 spondence in various directions about Portsmouth and 
 Devonport, and in March I went to Devonport and specially 
 examined Mount Wise and the Devonport Column. I had 
 correspondence with Sir Howard Douglas about the sea 
 breaking over the unfinished Dover Pier. I have an idea 
 that this followed evidence given by me to a Harbour Com- 
 mission, in which I expressed as a certainty that the sea will 
 not be made to break by a vertical wall." 
 
 Of private history : " I returned from Playford on Jan. 
 1 8th. From June i6th to August 5th I was, with my son 
 Wilfrid, on an expedition to South Italy and Sicily : on 
 our return from Sicily, we remained for three days ill at 
 Marseilles from a touch of malaria. On Dec. 22nd I went to 
 Playford. In acknowledgment of the pleasure which I had 
 derived from excursions in the Cumberland Passes, I made 
 a foot-bridge over a troublesome stream on the Pass of the 
 Sty Head." 
 
 1857 
 
 " In the Report to the Visitors, when on the subject of 
 the Altazimuth, the following paragraph occurs : ' I alluded 
 in a preceding section to the cutting away of a very small 
 portion of one of the rays of the three-armed pier which 
 carries the Altazimuth. The quality of the brickwork is 
 the best that I have ever seen, and not a single brick was 
 disturbed beyond those actually removed. Yet the effect 
 was to give the Altazimuth an inclination of about 25". 
 
AT GREENWICH OBSERVATORY 1856 TO 1 866. 229 
 
 This inclination evidently depends on the elasticity of the 
 brickwork.' With reference to the new S.E. Equatoreal the 
 Report states that * The support of the north or upper end of 
 the polar axis has been received, and is planted within the 
 walls of the building in a position convenient for raising it to 
 its ultimate destination. It is one piece of cast-iron, and 
 weighs nearly 5 tons.' Small changes as previously men- 
 tioned had been noticed with regard to the Zero of Azimuth 
 of the Transit Circle, and the Report states that * In regard 
 to the Azimuth of the Transit Circle, and the Azimuth of its 
 Co-llimator, Mr Main has brought together the results of 
 several years, and the following law appears to hold. There 
 is a well-marked annual periodical change in the position of 
 the Transit Circle, the southerly movement of the eastern 
 pivot having its minimum value in September, and its maxi- 
 mum in March, the extreme range being about 14 seconds ; 
 and there is a similar change, but of smaller amount, in the 
 position of the Collimator. I cannot conjecture any cause 
 for these changes, except in the motion of the ground. 
 There is also a well-marked connection between the state of 
 level of the axis and the temperature. The eastern pivot 
 always rises when the temperature rises, the extreme range 
 being about 6 seconds. I cannot offer any explanation of 
 this.' Under the head of Extraneous Works the Report 
 states that ' The British Government had for some years past 
 contributed by pecuniary grants to the preparation of Prof. 
 Hansen's Lunar Tables. In the last winter they undertook 
 the entire expense of printing a large impression of the 
 Tables. The reading of the proof-sheets (a very considerable 
 labour) has been effected entirely at the Observatory. I may 
 take this opportunity of stating that the use of these Tables 
 has enabled me, as I think, incontestably to fix the capture 
 of Larissa to the date B.C. 557, May 19. This identification 
 promises to prove valuable, not merely for its chronological 
 utility, but also for its accurate determination of an astro- 
 nomical epoch, the point eclipsed being exactly known, and 
 
230 GEORGE BIDDELL AIRY. 
 
 the shadow having been very small.' In April I gave a 
 lecture to the Royal Astronomical Society on the methods 
 available through the next 25 years for the determination of 
 the Sun's parallax. Dr Livingstone's observations for African 
 longitudes were computed at the Observatory. The Ad- 
 miralty enquire of me about the feasibility of adopting 
 Piazzi Smyth's construction for steadying telescopes on board 
 ship : I gave a Report, of mixed character, on the whole dis- 
 couraging. I had correspondence with G. P. Bond and others 
 about photographing the Stars and Moon. On Feb. i/th 
 Piazzi Smyth's books, &c. relating to the Teneriffe Experi- 
 ment were sent to me : I recommended that an abridged 
 Report should be sent to the Royal Society. Respecting the 
 Sheepshanks Fund : there was correspondence with Miss 
 Sheepshanks and Whewell, but nothing got into shape this 
 year: Miss Sheepshanks transferred to me ^"10,000 lying at 
 Overend and Gurney's. In November experiments were 
 made for the longitude of Edinburgh, which failed totally 
 from the bad state of the telegraph wire between Deptford 
 and the Admiralty. In June the first suggestion was made 
 to me by Capt. Washington for time-signals on the Lizard 
 Point : which in no long time I changed for the Start Point. 
 The Admiralty call for estimates for a time-ball at Ports- 
 mouth : on receiving them they decline further proceeding. 
 I was engaged in speculations and correspondence about the 
 Atlantic Submarine Cable. In the Royal Astronomical 
 Society, I presented Memoirs and gave lectures on the three 
 great chronological eclipses (Agathocles, Thales, Larissa)." 
 On Dec. 5th Airy wrote to the Vice-Chancellor of the Uni- 
 versity of Cambridge, objecting to the proposed changes 
 regarding the Smith's Prizes a subject in which he took 
 much interest, and to which he ascribed great importance. 
 " On Apr. 27th I was in correspondence with G. Herbert of 
 the Trinity House, about floating beacons. In July I re- 
 ported to the Treasury on the Swedish Calculating Engine 
 (I think on the occasion of Mr Farr, of the Registrar- 
 
AT GREENWICH OBSERVATORY 1856 TO 1866. 231 
 
 General's Office, applying for one). In November I had 
 correspondence about the launch of the Great Eastern, and 
 the main drainage of London." 
 
 Of private history : " On Jan. I4th I returned from Play- 
 ford. From June 2/th to Aug. 5th I was travelling in 
 Scotland with my wife and two eldest sons, chiefly in the 
 West Highlands. On our return we visited Mrs Smith (my 
 wife's mother) at Brampton. On -Dec. 26th I went to 
 Playford." 
 
 1858 
 
 " In the Minutes of the Visitors it is noted that the new 
 Queen's Warrant was received. The principal change was the 
 exclusion of the Astronomer Royal and the other Observatory 
 Officers from the Board. In the Report to the Visitors it is 
 stated that ' The Papers of the Board of Longitude are now 
 finally stitched into books. They will probably form one of 
 the most curious collections of the results of scientific enter- 
 prise, both normal and abnormal, which exists.' It appears 
 that the galvanic communications, external to the Observa- 
 tory, had been in a bad state, the four wires to London 
 Bridge having probably been injured by a thunderstorm in 
 the last autumn, and the Report states that ' The state of the 
 wires has not enabled us to drop the Ball at Deal. The 
 feeble current which arrives there has been used for some 
 months merely as giving a signal, by which an attendant is 
 guided in dropping the Ball by hand/ Regarding the new 
 Equatoreal the Report states that 'For the new South-East 
 Equatoreal, the object-glass was furnished by Messrs Merz 
 and Son in the summer of last year, and I made various trials 
 of it in a temporary tube carried by the temporary mounting 
 which I had provided, and finally I was well satisfied with it. 
 I cannot yet say that I have certainly divided the small star 
 of 7 Andromedae ; but, for such a test, a combination of 
 favourable circumstances is required. From what I have 
 
232 GEORGE BIDDELL AIRY. 
 
 seen, I have no doubt of its proving a first-rate object-glass.' 
 On March I5th was an annular eclipse of the Sun, for the 
 observation of which I sent parties fully equipped to Bedford, 
 Wellingborough, and Market Ha-fborough. The observations 
 failed totally in consequence of the bad weather : I myself 
 went to Harrowden near Wellingborough. Respecting the 
 Altazimuth, the Report states that with due caution as to the 
 zero of azimuth 'the results of observation are extremely 
 good, very nearly equal to those of the meridional instru- 
 ment ; perhaps I might say that three observations with the 
 Altazimuth are equivalent to two with the Transit Circle.' 
 Respecting Meteorological Observations the Report states 
 that ' The observations of the maximum and minimum ther- 
 mometers in the Thames, interrupted at the date of the last 
 Report, have been resumed, and are most regularly main- 
 tained. Regarding the Thames as the grand climatic agent 
 on London and its neighbourhood, I should much regret the 
 suppression of these observations.' After much trouble the 
 longitude of Edinburgh had been determined : ' the retard of 
 the current is O'O4 S very nearly, and the difference of longi- 
 tudes I2 m 43'O5 S , subject to personal equations.' The Report 
 concludes thus : ' With regard to the direction of our labours, 
 I trust that I shall always be supported by the Visitors in 
 my desire to maintain the fundamental and meridional system 
 of the Observatory absolutely intact. This, however, does 
 not impede the extension of our system in any way whatever, 
 provided that such means are arranged for carrying out the 
 extension as will render unnecessary the withdrawal of 
 strength from what are now the engrossing objects of the 
 Observatory.' I had much correspondence on Comets, of 
 which Donati's great Comet was one : the tail of this Comet 
 passed over Arcturus on October 5th. Respecting the Sheep- 
 shanks Fund : In September I met Whewell at Leeds, and 
 we settled orally the final plan of the scheme. On Oct. 27th 
 I saw Messrs Sharp, Miss Sheepshanks's solicitors, and drew 
 up a Draft of the Deed of Gift. There was much corre- 
 
AT GREENWICH OBSERVATORY 1856 TO 1 866. 233 
 
 spondence, and on Nov. 2Oth I wrote to the Vice-Chancellor 
 of Cambridge University. A counter-scheme was proposed 
 by Dr Philpott, Master of St Catharine's College. By arrange- 
 ment I attended the Council of the University on Dec. 3rd, 
 and explained my views, to which the Council assented. On 
 Dec. Qth the Senate accepted the gift of Miss Sheepshanks. 
 I had much correspondence throughout this year, with the 
 Treasury, Herschel, Sabine, and the Royal Society, about the 
 continuation of the Magnetic Establishments. The Reduc- 
 tions of the Magnetic Observations 1848-1857 were com- 
 menced in February of this year, under the direction of Mr 
 Lucas, a computer who had been engaged on the Lunar 
 Reductions. In this year I came to a final agreement with 
 the South Eastern Railway Company about defining the 
 terms of our connection with them for the passage of Time 
 Signals. I was authorized by the Admiralty to sign the 
 'protocol' or Memorandum of Agreement, and it was signed 
 by the South Eastern Railway Directors. On Aug. 28th I 
 made my first proposal to Sir John Packington (First Lord 
 of the Admiralty) for hourly time signals on the Start Point, 
 and in September I went to the Start to examine localities, 
 &c. On Dec. 23rd the Admiralty declined to sanction it. I 
 presented to the Royal Society a Paper about drawing a 
 great-circle trace on a Mercator's chart. In October I gave 
 a Lecture on Astronomy in the Assembly Room at Bury. 
 On Jan. 2 5th I was busied with my Mathematical Tracts for 
 republication." In this year Airy published in the Athenaeum 
 very careful and critical remarks on the Commissioners' Draft 
 of Statutes for Trinity College. He was always ready to take 
 action in the interests of his old College. This Paper pro- 
 cured him the warmest gratitude from the Fellows of the 
 College. 
 
 Of private history : " On Jan. 23rd I returned from Play- 
 ford. From July 5th to Aug. 6th I was on an expedition in 
 Switzerland with my two eldest sons. At Paris we visited 
 Le Verrier, and at Geneva we visited Gautier, De La Rive, 
 
234 GEORGE BIDDELL AIRY. 
 
 and Plantamour. We returned by Brussels. On Dec. 23rd I 
 went to Playford." In this year was erected in Play ford 
 Churchyard a granite obelisk in memory of Thomas Clark- 
 son. It was built by subscription amongst a few friends of 
 Clarkson's, and the negociations and arrangements were 
 chiefly carried out by Airy, who zealously exerted himself in 
 the work which was intended to honour the memory of his 
 early friend. It gave him much trouble during the years 
 1856 to 1858. 
 
 Here is a letter to the Editor of the Athenaeum on some 
 other Trinity matters: 
 
 1858, November 22. 
 DEAR SIR, 
 
 In the Athenaeum of November 20, page 650, column 3, 
 paragraph 4, there is an account of the erection of the statue of 
 Barrow in Trinity College Antechapel (Cambridge) conceived in a 
 spirit hostile to the University, and written in great ignorance of the 
 facts. On the latter I can give the writer some information. 
 
 The Marquis of Lansdowne, who was a Trinity man and whose 
 son was of Trinity, intimated to the authorities of the College that 
 he was desirous of placing in the antechapel a statue of Milton. 
 This, regard being had to the customs and the college-feelings of 
 Cambridge, was totally impossible. The antechapel of every college 
 is sacredly reserved for memorials of the men of that college only; 
 and Milton was of Christ's College. The Marquis of Lansdowne, 
 on hearing this objection, left the choice of the person to be com- 
 memorated, to certain persons of the college, one of whom (a literary 
 character of the highest eminence and a profound admirer of Milton) 
 has not resided in Cambridge for many years. Several names were 
 carefully considered, and particularly one (not mentioned by your 
 correspondent) of very great literary celebrity, but in whose writings 
 there is ingrained so much of ribaldry and licentiousness that he was 
 at length given up. Finally the choice rested on Barrow, not as 
 comparable to Milton, but as a person of reputation in his day and 
 as the best who could be found under all the circumstances. 
 
 Cromwell never was mentioned ; he was a member of Sidney 
 
AT GREENWICH OBSERVATORY 1856 TO 1 866. 235 
 
 College: moreover it would have been very wrong to select the 
 exponent of an extreme political party. But Cromwell has I believe 
 many admirers in Cambridge, to which list I attach myself. 
 
 I had no part in the negociations above mentioned, but I saw 
 the original letters, and I answer for the perfect correctness of what 
 I have stated. But as I am not a principal, I decline to appear in 
 public. 
 
 It is much to be desired, both for the Athenaeum and for the 
 public, that such an erroneous statement should not remain uncor- 
 rected. And I would suggest that a correction by the Editor would 
 be just and graceful, and would tend to support the Athenaeum in 
 that high position which it has usually maintained. 
 
 I am, dear Sir, 
 
 Yours very faithfully, 
 
 G. B. AIRY. 
 
 Hepworth Dixon, Esq. 
 
 1859 
 
 "The Report to the Visitors states that 'The Lunar 
 Reductions with amended elements (especially parallax) for 
 correction of Observations from 1831 to 1851 are now com- 
 pleted. It is, I think, matter of congratulation to the Obser- 
 vatory and to Astronomy, that there are now exhibited the 
 results of uninterrupted Lunar Observations extending through 
 more than a century, made at the same place, reduced under 
 the same superintendence and on the same general principles, 
 and compared throughout with the same theoretical Tables.' 
 After reference to the great value of the Greenwich Lunar 
 Observations to Prof. Hansen in constructing his Tables, and 
 to the liberality of the British Government in their grants to 
 Hansen, the Report continues thus : ' A strict comparison of 
 Hansen's Tables with the Greenwich Observations of late 
 years, both meridional and extra-meridional, was commenced. 
 The same observations had, in the daily routine of the Obser- 
 vatory, been compared with the Nautical Almanac or Burck- 
 
236 GEORGE BIDDELL AIRY. 
 
 hardt's Tables. The result for one year only (1852) has yet 
 reached me, but it is most remarkable. The sum of squares 
 of residual errors with Hansen's Tables is only one-eighth 
 part of that with Burckhardt's Cables. When it is remem- 
 bered that in this is included trie entire effect of errors and 
 irregularities of observation, we shall be justified in consider- 
 ing Hansen's Tables as nearly perfect. So great a step, to 
 the best of my knowledge, has never been made in numerical 
 physical theory. I have cited this at length, not only as 
 interesting to the Visitors from the circumstance that we 
 have on our side contributed to this great advance, but also 
 because an innovation, peculiar to this Observatory, has in no 
 small degree aided in giving a decisive character to the com- 
 parison. I have never concealed my opinion that the intro- 
 duction and vigorous use of the Altazimuth for observations 
 of the Moon is the most important addition to the system of 
 the Observatory that has been made for many years. The 
 largest errors of Burckhardt's Tables were put in evidence 
 almost always by the Altazimuth Observations, in portions of 
 the Moon's Orbit which could not be touched by the meri- 
 dional instruments ; they amounted sometimes to nearly 40" 
 of arc, and they naturally became the crucial errors for dis- 
 tinction between Burckhardt's and Hansen's Tables. Those 
 errors are in all cases corrected with great accuracy by Han- 
 sen's Tables.' The Report concludes with the following 
 paragraph : ' With the inauguration of the new Equatoreal 
 will terminate the entire change from the old state of the 
 Observatory. There is not now a single person employed or 
 instrument used in the Observatory which was there in Mr 
 Pond's time, nor a single room in the Observatory which is 
 used as it was used then. In every step of change, however, 
 except this last, the ancient and traditional responsibilities of 
 the Observatory have been most carefully considered : and, 
 in the last, the substitution of a new instrument was so abso- 
 lutely necessary, and the importance of tolerating no instru- 
 ment except of a high class was so obvious, that no other 
 
AT GREENWICH OBSERVATORY 1856 TO 1 866. 237 
 
 course was open to us. I can only trust that, while the use 
 of the Equatoreal within legitimate limits may enlarge the 
 utility and the reputation of the Observatory, it may never 
 be permitted to interfere with that which has always been 
 the staple and standard work here.' Concerning the Sheep- 
 shanks Fund : There was much correspondence about settling 
 the Gift till about Feb. 2ist. I took part in the first exami- 
 nation for the Scholarship in October of this year, and took 
 my place with the Trinity Seniority, as one of their number 
 on this foundation, for some general business of the Fund. 
 With respect to the Correction of the Compass in Iron Ships : 
 I sent Mr Ellis to Liverpool to see some practice there in the 
 correction of the Compass. In September I urged Mr Rundell 
 to make a voyage in the Great Eastern (just floated) for 
 examination of her compasses, and lent him instruments : 
 very valuable results were obtained. Mr Archibald Smith 
 had edited Scoresby's Voyage in the Royal Charter, with an 
 introduction very offensive to me : I replied fully in the 
 Athenaeum of Nov. 7th. The Sale of Gas Act : An Act of 
 Parliament promoted by private members of the House of 
 Commons had been passed, without the knowledge or recol- 
 lection of the Government. It imposed on the Government 
 various duties about the preparation of Standards. Suddenly, 
 at the very expiration of the time allowed this came to the 
 knowledge of Government. On Oct. ist Lord Monteagle 
 applied to me for assistance. On Oct. 15th and 22nd I wrote- 
 to Mr Hamilton, Secretary of the Treasury, and received 
 authority to ask for the assistance of Prof. W. H. Miller. I 
 made an examination of Mr Ball's eyes (long-sighted and 
 short-sighted I think). In February I made an Analysis of 
 the Cambridge Tripos Examination, which I communicated 
 to some Cambridge residents," In a letter on this subject to 
 one of his Cambridge friends Airy gives his opinion as 
 follows : " I have looked very carefully over the Examination 
 Papers, and think them on the whole very bad. They are 
 utterly perverted by the insane love of Problems, and by the 
 
238 GEORGE BIDDELL AIRY. 
 
 foolish importance given to wholly useless parts of Alge- 
 braical Geometry. For the sake of these, every Physical 
 Subject and every useful application of pure mathematics are 
 cut down or not mentioned." T?his led to much discussion at 
 Cambridge. In this year the Smith's Prizes were awarded to 
 the 4th and 6th Wranglers. 
 
 Of private history : " On Apr. 29th Mrs Smith (my wife's 
 mother) died at Brampton. From July 4th to Aug. 2nd I 
 was in France (Auvergne and the Vivarais) with my two 
 eldest sons. Maclear travelled with us to Paris. On Dec. 
 23rd I went to Playford." Antiquities and historical ques- 
 tions connected with military movements had a very great 
 attraction for Airy. On his return from the expedition in 
 France above-mentioned, he engaged in considerable corre- 
 spondence with military authorities regarding points con- 
 nected with the battle of Toulouse. And in this year also 
 he had much correspondence with the Duke of Northumber- 
 land concerning his Map of the Roman Wall, and the military 
 points relating to the same. 
 
 1860 
 
 " In June Mr Main accepted the office of Radcliffe Observer 
 at Oxford (Mr Johnson having died) and resigned the First 
 Assistancy at Greenwich : in October Mr Stone was appointed 
 First Assistant. At an adjourned Meeting of the Visitors on 
 June 1 8th there were very heavy discussions on Hansen's 
 merits, and about the grant to him. Papers were read from 
 Sir J. Lubbock, Babbage, South, Whewell, and me. Finally 
 it was recommended to the Government to grant ;iooo to 
 Hansen, which was paid to him. In the Report to the Board 
 of Visitors the following remark occurs : * The apparent exist- 
 ence of a discordance between the results of Direct Observa- 
 tions and Reflection Observations (after the application of 
 corrections for flexure, founded upon observations of the 
 horizontal collimator wires) to an extent far greater than can 
 
AT GREENWICH OBSERVATORY 1856 TO 1 866. 239 
 
 be explained by any disturbance of the direction of gravity 
 on the quicksilver by its distance from the vertical, or by the 
 attraction of neighbouring masses, perplexes me much.' 
 With respect to the discordance of dips of the dipping-needles, 
 which for years past had been a source of great trouble and 
 puzzle, the Report states that ( The dipping-needles are still a 
 source of anxiety. The form which their anomalies appear 
 to take is that of a special or peculiar value of the dip given 
 by each separate needle. With one of the 9-inch needles, 
 the result always differs about a quarter of a degree from that 
 of the others. I can see nothing in its mechanical construc- 
 tion to explain this. Reference is made to the spontaneous 
 currents through the wires of telegraph companies, which are 
 frequently violent and always occur at the times of magnetic 
 storms, and the Report continues ' It may be worth consider- 
 ing whether it would ever be desirable to establish in two 
 directions at right angles to each other (for instance, along 
 the Brighton Railway and along the North Kent Railway) 
 wires which would photographically register in the Royal 
 Observatory the currents that pass in these directions, exhi- 
 biting their indications by photographic curves in close juxta- 
 position with the registers of the magnetic elements.' In 
 connection with the Reduction of the Greenwich Lunar 
 Observations from 1831 to 1851, the Report states that 'The 
 comparison of Hansen's Lunar Tables with the Greenwich 
 Observations, which at the last Visitation had been completed 
 for one year only, has now been finished for the twelve years 
 1847 to ^58. The results for the whole period agree entirely, 
 in their general spirit, with those for the year 1852 cited in 
 the last Report. The greatest difference between the merits 
 of Burckhardt's and Hansen's Tables appears in the Meri- 
 dional Longitudes 1855, when the proportion of the sum of 
 squares of errors is as 31 (Burckhardt) to 2 (Hansen). The 
 nearest approach is in the Altazimuth Latitudes 1854, when 
 the proportion of the sum of squares of errors is as 12 
 (Burckhardt) to 5 (Hansen).' A special Address to the Mem- 
 
240 GEORGE BIDDELL AIRY. 
 
 bers of the Board of Visitors has reference to the proposals of 
 M. Struve for (amongst other matters) the improved deter- 
 mination of the longitude of Valencia, and the galvanic deter- 
 mination of the extreme Eastern Station of the British 
 triangles. On Sept. I3th I circulated amongst the Visitors 
 my Remarks on a Paper entitled ' On the Polar Distances of 
 the Greenwich Transit-Circle, by A. Marth,' '"printed in the 
 Astronomische Nachrichten ; the Paper by Mr Marth was an 
 elaborate attack on the Greenwich methods of observation, 
 and my Remarks were a detailed refutation of his statements. 
 On Oct. 2Oth I made enquiry of Sabine as to the advan- 
 tage of keeping up magnetic observations. On Oct. 22nd he 
 wrote, avoiding my question in some measure, but saying 
 that our instruments must be changed for such as those at 
 Kew (his observatory) : I replied, generally declining to act 
 on that advice. In March and April I was in correspondence 
 with Mr Cowper (First Commissioner of Works, &c.) about 
 the bells of the Westminster Clock ; also about the smoky 
 chimneys of the various apartments of the Palace. On Apr. 
 2 ist I made my Report on the clock and bells, 20 foolscap 
 pages. I employed a professional musician to examine the 
 tones of the bells. In November I was writing my book on 
 Probable Errors, &c. I was engaged on the Tides of Kurra- 
 chee and Bombay. The first examination of Navy telescopes 
 was made for the Admiralty. Hoch's Paper on Aberration 
 appeared in the Astronomische Nachrichten. This (with 
 others) led to the construction of the water-telescope several 
 years later. In September I wrote in the Athenaeum against 
 a notion of Sir H. James on the effect of an upheaval of a 
 mountain in changing the Earth's axis. In October I had 
 drawn up a list of days for a possible evagation of the Earth's 
 poles : but apparently nothing was done upon them. 
 
 " In this year I was a good deal occupied for the Light- 
 house Commission. On Feb. 2ist Admiral Hamilton (chair- 
 man) applied to me for assistance. In April I went to 
 Chance's Factory in Birmingham on this business. In May 
 
AT GREENWICH OBSERVATORY 1856 TO 1 866. 24! 
 
 I made my report on the Start Lighthouse, after inspection 
 with the Commission. In June, with my son Hubert, I 
 visited the Whitby Lighthouses, and discovered a fault of a 
 singular kind which most materially diminished their power. 
 This discovery led to a general examination of lighthouses 
 by the Trinity Board, to a modification of many, and to a 
 general improvement of system. On June 25th I reported 
 on the Lights at Calais, Cap de Valde, Grisnez, South Fore- 
 land, and North Foreland. In August I had been to the 
 North Foreland again, and in September to Calais and the 
 Cap d'Ailly. In October I went with my son Hubert to 
 Aberdeen to see the Girdleness Lighthouse. On Nov. loth 
 I made a General Report. 
 
 " This was the year of the great total solar eclipse visible 
 in Spain. At my representation, the Admiralty placed at 
 my command the large steamship ' Himalaya ' to carry about 
 60 astronomers, British and Foreign. Some were landed at 
 Santander : I with many at Bilbao. The Eclipse was fairly 
 well observed : 1 personally did not do my part well. The 
 most important were Mr De La Rue's photographic opera- 
 tions. At Greenwich I had arranged a very careful series of 
 observations with the Great Equatoreal, which were fully 
 carried out." 
 
 The eclipse expedition to Spain, shortly referred to 
 above, was most interesting, not merely from the importance 
 of the results obtained (and some of the parties were very 
 fortunate in the weather) but from the character of the expe- 
 dition. It was a wonderful combination of the astronomers 
 of Europe, who were all received on board the ' Himalaya,' 
 and were conveyed together to the coast of Spain. The 
 polyglot of languages was most remarkable, but the utmost 
 harmony and enthusiasm prevailed from first to last, and this 
 had much to do with the general success of the expedition. 
 Those who landed at Bilbao were received in the kindest and 
 most hospitable manner by Mr C. B. Vignoles, the engineer- 
 in-chief of the Bilbao and Tudela Railway, which was then 
 A. B. 16 
 
242 GEORGE BIDDELL AIRY. 
 
 under construction. This gentleman made arrangements for 
 the conveyance of parties to points in the interior of the 
 country which were judged suitable for the observation of the 
 eclipse, and placed all the resources of his staff at the disposal 
 of the expedition in the most liberal manner. The universal 
 opinion was that very great difficulty would have been expe- 
 rienced without the active and generous assistance of Mr 
 Vignoles. It is needless to say that the vote of thanks to 
 Mr Vignoles, proposed by the Astronomer Royal during the 
 return voyage, was passed by acclamation and with a very 
 sincere feeling of gratitude : it was to the effect that ' without 
 the great and liberal aid of Mr C. B. Vignoles, and the dis- 
 interested love of science evinced by him on this occasion, 
 the success of the "Himalaya" eclipse expedition could not 
 have been ensured.' There is a graphic and interesting 
 account of the reception of the party at Bilbao given in the 
 'Life of C. B. Vignoles, F.R.S., Soldier and Civil Engineer/ 
 by O. J. Vignoles, M.A. 
 
 Of private history : " On May 26th my venerable friend 
 Arthur Biddell died. He had been in many respects more 
 than a father to me : I cannot express how much I owed to 
 him, especially in my youth. From June I2th to i$th I 
 visited the Whitby Lighthouses with my son Hubert. From 
 July 6th to 28th I was in Spain, on the ' Himalaya' expedi- 
 tion, to observe the total eclipse : I was accompanied by my 
 wife, my eldest son, and my eldest daughter. From Oct. 5th 
 to 1 8th I went with my son Hubert to Aberdeen to see the 
 Girdleness Lighthouse, making lateral trips to Cumberland 
 in going and returning. On Dec. 2ist I went to Playford." 
 
 1861 
 
 " In the Report to the Visitors there is great complaint of 
 want of room. ' With increase of computations, we want 
 more room for computers ; with our greatly increased busi- 
 ness of Chronometers and Time-Distribution, we are in want 
 
AT GREENWICH OBSERVATORY 1856 TO 1 866. 243 
 
 of a nearly separate series of rooms for the Time-Depart- 
 ment : we want rooms for book-stores ; and we require rooms 
 for the photographic operations and the computations of the 
 Magnetic Department.' The Report gives a curious history 
 of Dr Bradley 's Observations, which in 1776 had been trans- 
 ferred to the University of Oxford, and proceeds thus: 
 1 More lately, I applied (in the first instance through Lord 
 Wrottesley) to the Vice-Chancellor, Dr Jeune, in reference to 
 the possibility of transferring these manuscripts to the Royal 
 Observatory.... Finally, a decree for the transfer of the manu- 
 script observations to the Royal Observatory, without any 
 condition, was proposed to Convocation on May 2nd, and 
 was passed unanimously. And on May 7th my Assistant, 
 Mr Dunkin, was sent to Oxford to receive them. And thus, 
 after a delay of very nearly a century, the great work of 
 justice is at length completed, and the great gap in our 
 manuscript observations is at length filled up/ With ref- 
 erence to the Transit Circle, it had been remarked that the 
 Collimators were slightly disturbed by the proximity of the 
 gas-flames of their illuminators, and after various experi- 
 ments as to the cause of it, the Report proceeds thus : * To 
 my great surprise, I found that the disturbance was entirely 
 due to the radiation of the flame upon a very small corner 
 (about 1 6 square inches) of the large and massive stone on 
 which the collimator is planted. The tin plates were subse- 
 quently shaped in such a manner as to protect the stone as 
 well as the metal ; and the disturbance has entirely ceased.' 
 Regarding the large S.E. Equatoreal, the Report states that 
 * On the character of its object-glass I am now able to speak, 
 first, from the examination of Mr Otto Struve, made in a 
 favourable state of atmosphere ; secondly, from the examina- 
 tions of my Assistants (I have not myself obtained a sight of 
 a test-object on a night of very good definition). It appears 
 to be of the highest order. The small star of y Andromedae 
 is so far separated as to shew a broad dark space between its 
 components. Some blue colour is shewn about the bright 
 
 16 2 
 
244 GEORGE BIDDELL AIRY. 
 
 planets.' It is noted in the Report that 'The Equatoreal 
 observations of the Solar Eclipse are completely reduced ; 
 and the results are valuable. It appears from them that the 
 error in right ascension of Burckhardt's Lunar Tables at the 
 time of the eclipse amounted to about 38" ; while that of 
 Hansen's (ultimately adopted by Mr Hind for. the calculation 
 of the eclipse) did not exceed 3".' With regard to Chrono- 
 meters it is stated that * By use of the Chronometer Oven, to 
 which I have formerly alluded, we have been able to give 
 great attention to the compensation. I have reason to think 
 that we are producing a most beneficial effect on the manu- 
 facture and adjustment of chronometers in general.' With 
 regard to the Cape of Good Hope Observatory and Survey, 
 the Admiralty enquire of me when the Survey work will be 
 completed, and I enquire of Maclear ' How is the printing of 
 your Survey Work?' In 1862 I began to press it strongly, 
 and in 1863 very strongly. I introduced a method (constantly 
 pursued since that time at the Royal Observatory) for com- 
 puting interpolations without changes of sign. I had cor- 
 respondence with Herschel and Faraday, on the possible 
 effect of the Sun's radiant heat on the sea, as explaining the 
 curve of diurnal magnetic inequality. (That diurnal in- 
 equality was inferred from the magnetic reductions 1848 
 1857, which were terminated in 1860.) Regarding the pro- 
 posal of hourly time-signals on the Start Point, I consulted 
 telegraph engineers upon the practical points, and on Dec. 
 2 ist I proposed a formal scheme, in complete detail. (The 
 matter has been repeatedly brought before the Admiralty, but 
 has been uniformly rejected.) I was engaged on the question 
 of the bad ocular vision of two or three persons. The British 
 Association Meeting was held at Manchester: I was President 
 of Section A. I gave a Lecture on the Eclipse of 1860 to an 
 enormous attendance in the Free Trade Hall." The following 
 record of the Lecture is extracted from Dr E. J. Routh's 
 Obituary Notice of Airy written for the Proceedings of the 
 Royal Society. " At the meeting of the British Association 
 
AT GREENWICH OBSERVATORY 1856 TO 1866. 245 
 
 at Manchester in 1861, Mr Airy delivered a Lecture on the 
 Solar Eclipse of 1860 to an assembly of perhaps 3000 
 persons. The writer remembers the great Free Trade Hall 
 crowded to excess with an immense audience whose attention 
 and interest, notwithstanding a weak voice, he was able to 
 retain to the very end of the lecture.... The charm of Pro- 
 fessor Airy's lectures lay in the clearness of his explanations. 
 The subjects also of his lectures were generally those to 
 which his attention had been turned by other causes, so that 
 he had much that was new to tell. His manner was slightly 
 hesitating, and he used frequent repetitions, which perhaps 
 were necessary from the newness of the ideas. As the 
 lecturer proceeded, his hearers forgot these imperfections and 
 found their whole attention rivetted to the subject matter." 
 
 Of private history : " On Jan. 2nd there was a most re- 
 markable crystallization of the ice on the flooded meadows 
 at Playford : the frost was very severe. From June 2Oth to 
 Aug. 1st I was at the Grange near Keswick (where I hired a 
 house) with my wife and most of my family. From Nov. 5th 
 to I4th I was on an expedition in the South of Scotland 
 with my son Wilfrid : we walked with our knapsacks by the 
 Roman Road across the Cheviots to Jedburgh. On Dec. 
 2 ist I went to Playford." 
 
 1862 
 
 " The Report to the Board of Visitors states that ' A new 
 range of wooden buildings (the Magnetic Offices) is in pro- 
 gress at the S.S.E. extremity of the Magnetic Ground. It will 
 include seven rooms.' Also ' I took this opportunity (the 
 relaying of the water-main) of establishing two powerful fire- 
 plugs (one in the Front Court, and one in the Magnetic 
 Ground); a stock of fire-hose adapted to the "Brigade-Screw" 
 having been previously secured in the Observatory.' 'Two 
 wires, intended for the examination of spontaneous earth- 
 currents, have been carried from the Magnetic Observatory 
 
246 GEORGE BIDDELL AIRY. 
 
 to the Railway Station in the town of Greenwich. From 
 this point one wire is to be led to a point in the neighbour- 
 hood of Croydon, the other to a point in the neighbourhood 
 of Dartford. Each wird is to /be connected at its two ex- 
 tremities with the Earth. The angle included between the 
 general directions of these two lines is nearly a right angle.' 
 'The Kew unifilar magnetometer, adapted to the deter- 
 mination of the horizontal part of terrestrial magnetic force 
 in absolute measure, was mounted in the summer of 1861 ; 
 and till 1862 February, occasional observations (14 in all) 
 were taken simultaneously with the old and with the new 
 instrument. The comparison of results shewed a steady but 
 very small difference, not greater probably than may cor- 
 respond to the omission of the inverse seventh powers of 
 distance in the theoretical investigation ; proving that the old 
 instrument had been quite efficient for its purpose.' Great 
 efforts had been made to deduce a law from the Diurnal 
 Inequalities in Declination and Horizontal Force, as shewn 
 by the Magnetic observations ; but without success : the 
 Report states that 'The results are most amazing, for the 
 variation in magnitude as well as in law. What cosmical 
 change can be indicated by them is entirely beyond my 
 power of conjecture.' * I have alluded, in the two last Re- 
 ports, to the steps necessary, on the English side, for com- 
 pleting the great Arc of Parallel from Valencia to the Volga. 
 The Russian portion of the work is far advanced, and will be 
 finished (it is understood) in the coming summer. It ap- 
 peared to me therefore that the repetition of the measure of 
 astronomical longitude between Greenwich and Valencia could 
 be no longer delayed. Two Assistants of the Royal Obser- 
 vatory (Mr Dunkin and Mr Criswick) will at once proceed to 
 Valencia, for the determination of local time and the manage- 
 ment of galvanic signals.' ' I now ask leave to press the sub- 
 ject of Hourly Time Signals at the Start Point on the atten- 
 tion of the Board, and to submit the advantage of their 
 addressing the Board of Admiralty upon it. The great 
 
AT GREENWICH OBSERVATORY 1856 TO 1 866. 247 
 
 majority of outward-bound ships pass within sight of the 
 Start, and, if an hourly signal were exhibited, would have the 
 means of regulating their chronometers at a most critical 
 part of their voyage. The plan of the entire system of opera- 
 tions is completely arranged. The estimated expense of 
 outfit is 2017, and the estimated annual expense is 326 ; 
 both liable to some uncertainty, but sufficiently exact to 
 shew that the outlay is inconsiderable in comparison with 
 the advantages which might be expected from it. I know 
 no direction of the powers of the Observatory which would 
 tend so energetically to carry out the great object of its 
 establishment, viz. "the finding out the so much desired 
 Longitude at Sea." ' The attention of the Visitors is strongly 
 drawn to the pressure on the strength of the Observatory 
 caused by the observation of the numerous small planets, and 
 the paragraph concludes thus: 'I shall, however, again en- 
 deavour to effect a partition of this labour with some other 
 Observatory.' A small fire having occurred in the Magnetic 
 Observatory, a new building of zinc, for the operation of 
 naphthalizing the illuminating gas, is in preparation, external 
 to the Observatory : and thus one of the possible sources of 
 accidental fire will be removed. Miss Sheepshanks added, 
 through me, 2000 to her former gift: I transferred it, i 
 believe, to the Master and Seniors of Trinity College." In 
 this year Airy contributed to the Royal Society two Papers, 
 one " On the Magnetic properties of Hot-Rolled and Cold- 
 Rolled Malleable Iron," the other "On the Strains in the 
 Interior of Beams." He gave evidence before the Select 
 Committee on Weights and Measures, and also before the 
 Public Schools Commission. 
 
 In the latter part of 1862 a difference arose between Airy 
 and Major-General Sabine, in consequence of remarks made 
 by the latter at a meeting of the Committee of Recommen- 
 dations of the British Association. These remarks were to 
 the effect "That it is necessary to maintain the complete 
 system of self-registration of magnetic phaenomena at the 
 
248 GEORGE BIDDELL AIRY. 
 
 Kew Observatory, because no sufficient system of magnetic 
 record is maintained elsewhere in England " ; implying 
 pointedly that the system at the Royal Observatory of 
 Greenwich was insufficient. Ttyis matter was taken up very 
 warmly by Airy, and after a short and acrimonious cor- 
 respondence with Sabine, he issued a private Address to the 
 Visitors, enclosing copies of the correspondence with his 
 remarks, and requesting the Board to take the matter of this 
 attack into their careful consideration. This Address is 
 dated November 1862, and it was followed by another dated 
 January 1863, which contains a careful reply to the various 
 points of General Sabine's attack, and concludes with a 
 distinct statement that he (the Astronomer Royal) can no 
 longer act in confidence with Sabine as a Member of the 
 Board of Visitors. 
 
 Of private history : There were the usual short visits to 
 Playford at the beginning and end of the year. From June 
 28th to Aug. 5th he was in Scotland (chiefly in the Western 
 Highlands) with his wife and his sons Hubert and Osmund. In 
 the course of this journey he visited the Corryvreckan whirl- 
 pool near the island of Scarba, and the following paragraph 
 relating to this expedition is extracted from his journal : 
 "Landed in Black Mile Bay, island of Luing, at 10.30. Here 
 by previous arrangement with Mr A. Brown, agent of the 
 steam-boat company, a 4-oared boat was waiting to take us 
 to Scarba and the Corryvreckan. We were pulled across to 
 the island of Lunga, and rowed along its length, till we came 
 to the first channel opening from the main sea, which the 
 sailors called the Little Gulf. Here the sea was rushing 
 inwards in a manner of which I had no conception. Streams 
 were running with raving speed, sometimes in opposite direc- 
 tions side by side, with high broken-headed billows. Where 
 the streams touched were sometimes great whirls (one not 
 many yards from our boat) that looked as if they would suck 
 anything down. Sometimes among all this were great smooth 
 parts of the sea, still in a whirling trouble, which were sur- 
 
AT GREENWICH OBSERVATORY 1856 TO 1 866. 249 
 
 rounded by the mad currents. We seemed entirely powerless 
 among all these." 
 
 In the beginning of this year (1862) the Duke of Man- 
 chester, in writing to the Rev. W. Airy, had said, " I wish 
 your brother, the Astronomer Royal, could be induced to 
 have investigations made as to whether the aspects of the 
 Planets have any effect on the weather." This enquiry pro- 
 duced the following reply : 
 
 A subject like that of the occult influences of the planets (using 
 the word occult in no bad sense but simply as meaning not 
 thoroughly traced) can be approached in two ways either by the 
 a priori probability of the existence of such influences, or by the a 
 posteriori evidence of their effects. If the two can be combined, 
 the subject may be considered as claiming the dignity of a science. 
 Even if the effects alone are certain, it may be considered that we 
 have a science of inferior degree, wanting however that definiteness of 
 law and that general plausibility which can only be given when true 
 causes, in accordance with antecedent experience in other cases, can 
 be suggested. 
 
 Now in regard to the a priori probability of the existence of 
 planetary influences, I am far from saying that such a thing is im- 
 possible. The discoveries of modern philosophy have all tended to 
 shew that there may be many things about us, unknown even to the 
 scientific world, but which well-followed accidents reveal with the 
 most positive certainty. It is known that every beam of light is 
 accompanied by a beam of chemical agency, totally undiscoverable 
 to the senses of light or warmth, but admitting of separation from 
 the luminous and warm rays; and producing photogenic effects. 
 We know that there are disturbances of magnetism going on about 
 us, affecting whole continents at a time, unknown to men in general, 
 but traceable with facility and certainty, and which doubtless affect 
 even our brains and nerves (which are indisputably subject to the 
 influence of magnetism). 
 
 Now in the face of these things I will not undertake to say that 
 there is any impossibility, or even any want of plausibility in the 
 supposition that bodies external to the earth may affect us. It may 
 well be cited in its favour that it is certain that the sun affects our 
 magnetism (it is doubtful whether it does so /'^mediately, or 
 mediately by giving different degrees of warmth to different parts of 
 
250 GEORGE BIDDELL AIRY. 
 
 the earth), and it is believed on inferior evidence that the moon also 
 affects it. It may therefore seem not impossible or implausible that 
 other celestial bodies may affect perhaps others of the powers of 
 nature about us. But theie I must sj:op. The denial of the impos- 
 sibility is no assertion of the truth br probability, and I absolutely 
 decline to take either side either that the influences are real, or 
 that the influences are unreal till I see evidence of their effects. 
 
 Such evidence it is extremely difficult to extract from ordinary 
 facts of observation. I have alluded to the sun's daily disturbance 
 of the magnet as one of the most certain of influences, yet if you 
 were to observe the magnet for a single day or perhaps for several 
 days, you might see no evidence of that influence, so completely is 
 it involved with other disturbances whose causes and laws are totally 
 unknown. 
 
 I believe that, in addition to the effects ascribable to Newtonian 
 gravitation (as general motion of the earth, precession of the 
 equinoxes, and tides), this magnetic disturbance is the only one yet 
 established as depending on an external body. Men in general, 
 however, do not think so. It appears to be a law of the human 
 mind, to love to trace an effect to a cause, and to be ready to 
 assent to any specious cause. Thus all practical men of the lower 
 classes, even those whose pecuniary interests are concerned in it, 
 believe firmly in the influence of the moon upon the winds and 
 the weather. I believe that every careful examiner of recorded 
 facts (among whom I place myself as regards the winds) has come 
 to the conclusion that the influence of the moon is not discoverable. 
 
 I point out these two things (magnetic disturbances and 
 weather) as tending to shew that notoriety or the assumed consent 
 of practical men, are of no value. The unnotorious matter may be 
 quite certain, the notorious matter may have no foundation. Every- 
 thing must stand on its own evidence, as completely digested and 
 examined. 
 
 Of such evidence the planetary influence has not a particle. 
 
 My intended short note has, in the course of writing, grown up 
 into a discourse of very unreasonable length ; and it is possible that 
 a large portion of it has only increased obscurity. At any rate I can 
 add nothing, I believe, which can help to explain more fully my 
 views on this matter. 
 
AT GREENWICH OBSERVATORY 1856 TO 1 866. 25! 
 
 In this year (1862, June 9th) Airy received the Honorary 
 Degree of LL.D. in the University of Cambridge. He was 
 nominated by the Duke of Devonshire, as appears from the 
 following letter : 
 
 LISMORE CASTLE, IRELAND, 
 April I9//&, 1862. 
 
 MY DEAR SIR, 
 
 It is proposed according to usage to confer a considerable 
 number of Honorary Degrees on the occasion of my first visit to 
 Cambridge as Chancellor of the University. 
 
 I hope that you will allow me to include your name in that 
 portion of the list which I have been invited to draw up. 
 
 The ceremony is fixed for the loth of June. 
 
 I am, my dear Sir, 
 
 Yours very truly, 
 
 DEVONSHIRE. 
 
 The Astronomer Royal 
 
 Airy's reply was as follows : 
 
 ROYAL OBSERVATORY, GREENWICH, 
 LONDON, S.E. 
 
 1862, April 21. 
 
 MY LORD DUKE, 
 
 I am exceedingly gratified by your communication this 
 day received, conveying a proposal which I doubt not is suggested 
 by your Grace's recollection of transactions now many years past. 
 
 I have always been desirous of maintaining my connection with 
 my University, and have in various ways interested myself practically 
 in its concerns. It would give me great pleasure to have the con- 
 nection strengthened in the flattering way which you propose. 
 
252 GEORGE BIDDELL AIRY. 
 
 I had conceived that alumni of the University were not admissible 
 to honorary degrees ; but upon this point the information possessed 
 by your Grace, as Chancellor of the University, cannot be disputed. 
 
 '" -I am, rj0y Lord Duke, 
 Your Grace's very faithful servant, 
 
 G. B. AIRY. 
 His Grace 
 
 The Duke of Devonshire. 
 
 There were in all 19 Honorary Degrees of Doctor of Laws 
 conferred on the 9th of June, including men of such eminence 
 as Armstrong, Faraday, and Fairbairn. 
 
 1863 
 
 In this year there were several schemes for a Railway 
 through the lower part of Greenwich Park, the most 
 important being the scheme of the London, Chatham and 
 Dover Railway Company. In reference to this scheme the 
 Report to the Visitors states " I may say briefly that I 
 believe that it would be possible to render such a railway 
 innocuous to the Observatory ; it would however be under 
 restrictions which might be felt annoying to the authorities 
 of the Railway, but whose relaxation would almost ensure 
 ruin to the Observatory." " The meridional observations of 
 Mars in the Autumn of 1862 have been compared with those 
 made at the Observatory of Williamstown, near Melbourne, 
 Australia, and they give for mean solar parallax the value 
 8'932", exceeding the received value by about Jjth part. (A 
 value nearly identical with this 8*93" has also been found by 
 comparing the Pulkowa and Cape of Good Hope Observa- 
 tions.)" "The results of the new Dip-Instrument in 1861 
 and 1862 appear to give a firm foundation for speculations 
 on the state and change of the dip. As a general result, 
 
AT GREENWICH OBSERVATORY 1856 TO l866. 253 
 
 I may state as probable that the value of dip in the middle 
 of 1843 was about 69 i', and in the middle of 1862 about 
 68 u'. The decrease of dip appears to be more rapid in the 
 second half of this interval than in the first ; the dip at 
 beginning of 1853 being about 6844'." With reference to 
 the re-determination of the longitude of Valencia, it is stated 
 that " The concluded longitude agrees almost exactly with 
 that determined by the transmission of chronometers in 1844; 
 and entitles us to believe that the longitudes of Kingstown 
 and Liverpool, steps in the chronometer conveyance, were 
 determined with equal accuracy." "The computations, for 
 inferring the direction and amount of movement of the Solar 
 System in space from the observed proper motions of 1167 
 stars, have been completed. The result is, that the Sun 
 is moving towards a point, R.A. 264, N.P.D. 65 (not very 
 different from Sir W. HerschePs, but depending much in 
 N.P.D. on the accuracy of Bradley's quadrant observations), 
 and that its annual motion subtends, at the distance of a star 
 of the first magnitude, the angle 0-4". But the comparison, 
 of the sum of squares of apparent proper motions uncorrected, 
 with the sum of squares of apparent proper motions corrected 
 for motion of Sun, shews so small an advance in the explana- 
 tion of the star's apparent movements as to throw great 
 doubt on the certainty of results ; the sum of squares being 
 diminished by only ^th part." " I had been writing strongly 
 to Maclear on the delays in publishing both the geodetic 
 work and the Star Catalogue at the Cape of Good Hope : he 
 resolves to go on with these works. In December I am still 
 very urgent about the geodesy." 
 
 Of private history: There was the usual short visit to 
 Playford at the beginning and end of the year. "From 
 June 2/th to August roth I was travelling in the North and 
 West of Scotland with my wife, my youngest son Osmund, 
 and my daughter Annot." 
 
254 GEORGE BIDDELL AIRY. 
 
 In this year the offer of Knighthood (for the third time) 
 was made to Airy through the Rt Hon. Sir George C. Lewis, 
 Bart. The offer was accepted on Feb. I2th, 1863, but on the 
 same day a second letter was written as follows : 
 
 1863, Feb. 12. 
 DEAR SIR, 
 
 I am extremely ignorant of all matters connected with 
 court ceremonial, and in reference to the proposed Knighthood 
 would ask you : 
 
 1. I trust that there is no expense of fees. To persons like 
 myself of small fortune an honour may sometimes be somewhat dear. 
 
 2. My highest social rank is that given by my Academical 
 Degree of D.C.L. which I hold in the Universities of Oxford and 
 Cambridge. In regard to costume, would it be proper that I should 
 appear in the scarlet gown of that degree ? or in the ordinary Court 
 Dress ? 
 
 I am, Dear Sir, 
 
 Yours very faithfully, 
 
 G. B. AIRY. 
 
 The Right Honourable 
 
 Sir George C. Lewis, Bart., 
 
 To this letter Sir G. C. Lewis replied that the fees would 
 amount to about ,30, an intimation which produced the 
 following letter : 
 
 ROYAL OBSERVATORY, GREENWICH, S.E. 
 
 1863, Fed. \tyh. 
 DEAR SIR, 
 
 I have to acknowledge your letter of yesterday : and I 
 advert to that part of it in which it is stated that the Fees on Knight- 
 hood amount to about ^30. 
 
 Twenty-seven years ago the same rank was offered to me by 
 Lord John Russell and Mr Spring Rice (then Ministers of the 
 Crown), with the express notice that no fees would be payable. I 
 suppose that the usage (whatever it be) on which that notice was 
 founded still subsists. 
 
AT GREENWICH OBSERVATORY 1856 TO 1 866. 255 
 
 To a person whose annual income little more than suffices to 
 meet the annual expenses of a very moderate establishment, an 
 unsought honour may be an incumbrance. It appears, at any rate, 
 opposed to the spirit of such an honour, that it should be loaded 
 with Court Expenses in its very creation. 
 
 I hope that the principle stated in 1835 may serve as precedent 
 on this occasion. 
 
 I am, dear Sir, 
 
 Your very faithful servant, 
 
 G. B. AIRY. 
 
 The Right Honourable 
 
 Sir G. C. Lewis, Bart., 
 
 No intimation however was received that the fees would 
 be remitted on the present occasion, and after consideration 
 the proposed Knighthood was declined in the following 
 letter : 
 
 ROYAL OBSERVATORY, GREENWICH, S.E. 
 
 1863, April 15. 
 DEAR SIR, 
 
 I have frequently reflected on the proposal made by you 
 of the honour of Knighthood to myself. I am very grateful to you 
 for the favourable opinion which you entertain in regard to my 
 supposed claims to notice, and for the kindness with which you pro- 
 posed publicly to express it. But on consideration I am strongly 
 impressed with the feeling that the conditions attached by established 
 regulation to the conferring of such an honour would be unacceptable 
 to me, and that the honour itself would in reality, under the circum- 
 stances of my family-establishment and in my social position, be an 
 incumbrance to me. And finally I have thought it best most 
 respectfully, and with a full sense of the kindness of yourself and of 
 the Queen's Government towards me, to ask that the proposal might 
 be deferred. 
 
 There is another direction in which a step might be made, affect- 
 ing my personal position in a smaller degree, but not tending to 
 incommode me, which I would ask leave to submit to your considera- 
 tion. It is, the definition of the Rank of the Astronomer Royal. 
 The singular character of the office removes it from ordinary rules of 
 
256 GEORGE BIDDELL AIRY. 
 
 rank, and sometimes may produce a disagreeable contest of opinions. 
 The only offices of similar character corresponding in other conditions 
 to that of the British Astronomer Royal are those of the Imperial 
 Astronomers at Pulkowa -(St Petersburg) and Paris. In Russia, 
 where every rank is clearly defined by that of military grade, the 
 Imperial Astronomer has the rank of Major-General. In France, the 
 definition is less precise, but the present Imperial Astronomer has 
 been created (as an attachment of rank to the office) a Senator of 
 the Empire. 
 
 I am, dear Sir, 
 
 Your very faithful servant, 
 
 G. B. AIRY. 
 The Rt Hon. Sir George C. Lewis, Bart., 
 
 Sir G. C. Lewis died before receiving this letter, and the 
 letter was afterwards forwarded to Lord Palmerston. Some 
 correspondence followed between Lord Palmerston and Airy 
 on the subject of attaching a definite rank to the office of 
 Astronomer Royal, as proposed in the above letter. But the 
 Home Office (for various reasons set forth) stated that the 
 suggestion could not be complied with, and the whole subject 
 dropped. 
 
 1864 
 
 The following remarks are extracted from the Report of 
 the Astronomer Royal to the Board of Visitors. " In a very 
 heavy squall which occurred in the gale of December 2 of last 
 year, the stay of the lofty iron pillar ousi^e of the Park Rails, 
 which carried our telegraph wires, gave way, and the pillar 
 and the whole system of wires fell." " An important altera- 
 tion has been made in the Magnetic Observatory. For several 
 years past, various plans have been under consideration for 
 preventing large changes of temperature in the room which 
 contains the magnetic instruments. At length I determined 
 
AT GREENWICH OBSERVATORY 1856 TO l866. 257 
 
 to excavate a subterraneous room or cellar under the original 
 room. The work was begun in the last week in January, and 
 in all important points it is now finished." " In the late 
 spring, some alarm was occasioned by the discovery that the 
 Parliamentary Standard of the Pound Weight had become 
 coated with an extraneous substance produced by the decom- 
 position of the lining of the case in which it was preserved. 
 It was decided immediately to compare it with the three 
 Parliamentary Copies, of which that at the Observatory is 
 one. The National Standard was found to be entirely un- 
 injured." " On November 16 of last year, the Transit Instru- 
 ment narrowly escaped serious injury from an accident. The 
 plate chain which carries the large western counterpoise 
 broke. The counterpoise fell upon the pier, destroying the 
 massive gun-metal wheels of the lifting machinery, but was 
 prevented from falling further by the iron stay of the gas- 
 burner flue." " The Prismatic Spectrum- Apparatus had been 
 completed in 1863. Achromatic object-glasses are placed on 
 both sides of the prism, so that each pencil of light through 
 the prism consists of parallel rays ; and breadth is given to 
 the spectrum by a cylindrical lens. The spectral lines are 
 seen straighter than before, and generally it is believed that 
 their definition is improved." " For observation of the small 
 planets, a convention has been made with M. Le Verrier. 
 From new moon to full moon, all the small planets visible to 
 I3 h are observed at the Royal Observatory of Greenwich. 
 From full moon to new moon, all are observed at the Imperial 
 Observatory of Paris. The relief gained in this way is very 
 considerable." " In determining the variations in the power of 
 the horizontal-force and vertical-force magnets depending on 
 temperature, it was found by experiment that this depended 
 materially on whether the magnet was heated by air or by 
 water, and ' The result of these experiments (with air) is to 
 give a coefficient for temperature correction four or five times 
 as great as that given by the water-heatings.' " " With regard 
 to the discordances of the results of observations of dip- 
 A. B, 17 
 
258 GEORGE BIDDELL AIRY. 
 
 needles, experiments had been made with needles whose 
 breadth was in the plane passing through the axis of rotation, 
 and it appeared that the means of extreme discordances were, 
 for an ordinary needle n' 45'Vand for a flat needle 3' 27"," 
 and the Report continues thus : " After this I need not say 
 that I consider it certain that the small probable errors which 
 have been attributed to ordinary needles are a pure delusion." 
 The Report states that in the various operations connected 
 with the trials and repairs of chronometers, and the system of 
 time-signals transmitted to various time-balls and clocks, 
 about one-fourth of the strength of the Observatory is em- 
 ployed, and it continues thus : " Viewing the close dependence 
 of Nautical Astronomy upon accurate knowledge of time, 
 there is perhaps no department of the Observatory which 
 answers more completely to the original utilitarian intentions 
 of the Founder of the Royal Observatory." " With regard to 
 the proposal of time-signals at the Start Point, it appears that 
 communications referring to this proposal had passed between 
 the Board of Admiralty and the Board of Trade, of which the 
 conclusion was, that the Board of Trade possessed no funds 
 applicable to the defraying of the expenses attending the 
 execution of the scheme. And the Admiralty did not at 
 present contemplate the establishment of these time-signals 
 under their own authority." Amongst other Papers in this 
 year, Airy's Paper entitled "First Analysis of 177 Magnetic 
 Storms," &c., was read before the Royal Society. 
 
 Of private history : " There was the usual visit to Playford 
 in the beginning of the year. From June 8th to 23rd I made 
 an excursion with my son Hubert to the Isle of Man, and the 
 Lake District. From Sept. 7th to I4th I was on a trip to 
 Cornwall with my two eldest sons, chiefly in the mining 
 district. In August of this year my eldest (surviving) daugh- 
 ter, Hilda, was married to Mr E. J. Routh, Fellow of St Peter's 
 College, Cambridge, at Greenwich Parish Church. They after- 
 wards resided at Cambridge." 
 
AT GREENWICH OBSERVATORY 1856 TO 1 866. 259 
 
 1865 
 
 "Our telegraphic communications of every kind were 
 again destroyed by a snow-storm and gale of wind which 
 occurred on Jan. 28th, and which broke down nearly all the 
 posts between the Royal Observatory and the Greenwich 
 Railway Station. The Report to the Visitors states that 
 ' The only change of Buildings which I contemplate as at 
 present required is the erection of a fire-proof Chronometer 
 Room. The pecuniary value of Chronometers stored in the 
 Observatory is sometimes perhaps as much as .8000.' The 
 South Eastern and London Chatham and Dover scheme for 
 a railway through the Park was again brought forward. There 
 was a meeting of Sir J. Hanmer's Committee at the Observa- 
 tory on May 26th. Mr Stone was sent hastily to Dublin to 
 make observations on Earth-disturbance by railways there. 
 I had been before the Committee on May 25th. On Sept. ist 
 I approved of an amended plan. In reference to this matter 
 the Report states that ' It is proper to remark that the shake 
 of the Altazimuth felt in the earthquake of 1863, Oct. 5th, 
 when no such shake was felt with instruments nearer to the 
 ground (an experience which, as I have heard on private 
 authority, is supported by observation of artificial tremors), 
 gives reason to fear that, at distances from a railway which 
 would sufficiently defend the lower instruments, the loftier 
 instruments (as the Altazimuth and the Equatoreals) would 
 be sensibly affected.' Some of the Magnets had been sus- 
 pended by steel wires, instead of silk, of no greater strength 
 than was necessary for safety, and the Report states that 
 1 Under the pressure of business, the determination of various 
 constants of adjustment was deferred to the end of the year. 
 The immediate results of observation, however, began to 
 excite suspicion ; and after a time it was found that, in spite 
 of the length of the suspending wire (about 8 feet) the torsion- 
 coefficient was not much less than J. The wires were promptly 
 
 172 
 
260 GEORGE BIDDELL AIRY. 
 
 dismounted, and silk skeins substituted for them. With these, 
 the torsion-coefficient is about ^f^.' The Dip-Instrument, 
 which had given great trouble by the irregularities of the dip- 
 results, had been compared wifh two dip-instruments from 
 Kew Observatory, which gave very good and accordant 
 results. ' It happened that Mr Simms, by whom our instru- 
 ments now in use were prepared, and who had personally 
 witnessed our former difficulties, was present during some of 
 these experiments. Our own instrument being placed in his 
 hands (Nov. loth to ipth) for another purpose, he sponta- 
 neously re-polished the apparently faultless agate-bearings. 
 To my great astonishment, the inconsistencies of every kind 
 have nearly or entirely vanished. On raising and lowering 
 the needles, they return to the same readings, and the dips 
 with the same needle appear generally consistent.' Some 
 practical details of the polishing process by which this result 
 had been secured are then given. After numerous delays, 
 the apparatus for the self-registration of Spontaneous Earth 
 Currents was brought into a working state in the month of 
 March. A description of the arrangement adopted is given 
 in the Report. ' All Chronometers on trial are rated every 
 day, by comparison with one of the clocks sympathetic with 
 the Motor Clock. Every Chronometer, whether on trial or 
 returned from a chronometer-maker as repaired, is tried at 
 least once in the heat of the Chronometer-Oven, the tempera- 
 ture being usually limited to 90 Fahrenheit ; and, guided by 
 the results of very long experience, we have established it as 
 a rule, that every trial in heat be continued through three 
 weeks/ ' The only employment extraneous to the Observa- 
 tory which has occupied any of my time within the last year 
 is the giving three Lectures on the Magnetism of Iron Ships 
 (at the request of the Lords of the Committee of Council on 
 Education) in the Theatre of the South Kensington Museum. 
 The preparations, however, for these Lectures, to be given in 
 a room ill-adapted to them, occupied a great deal of my own 
 time, and of the time of an Assistant of the Observatory.' 
 
AT GREENWICH OBSERVATORY 1856 TO l866. 26l 
 
 ' Referring to a matter in which the interests of Astronomy 
 are deeply concerned, I think it right to report to the Visitors 
 my late representation to the Government, to the effect that, 
 in reference to possible observation of the Transit of Venus 
 in 1882, it will be necessary in no long time to examine 
 the coasts of the Great Southern Continent."' 
 
 Of private history : " There were the usual visits to Play- 
 ford at the beginning and end of the year. From June i8th 
 to 26th I was on a trip in Wales with my sons Hubert and 
 Osmund. From Sept. 6th to Oct. 2nd I was staying with 
 most of my family at Portinscale near Keswick : we returned 
 by Barnard Castle, Rokeby, &c." 
 
ft 
 
 CHAPTER VIII. 
 
 AT GREENWICH OBSERVATORY 1866 TO 1876. 
 
 1866 
 
 IN this year the cube of the Transit Circle was pierced, 
 to permit reciprocal observations of the Collimators without 
 raising the instrument. This involved the construction of 
 improved Collimators, which formed the subject of a special 
 Address to the Members of the Board of Visitors on Oct. 2ist 
 1865. From the Report to the Visitors it appears that " On 
 May 23rd 1865, a thunderstorm of great violence passed very 
 close to the Observatory. After one flash of lightning, I was 
 convinced that the principal building was struck. Several 
 galvanometers in the Magnetic Basement were destroyed. 
 Lately it has been remarked that one of the old chimneys 
 of the principal building had been dislocated and slightly 
 twisted, at a place where it was surrounded by an iron stay- 
 band led from the Telegraph Pole which was planted upon 
 the leads of the Octagon Room." " On consideration of the 
 serious interruptions to which we have several times been 
 exposed from the destruction of our open-air Park-wires 
 (through snow-storms and gales), I have made an arrange- 
 ment for leading the whole of our wires in underground pipes 
 as far as the Greenwich Railway Station." " The Committee 
 of the House of Commons, to whom the Greenwich and 
 Woolwich Line of the South Eastern Railway was referred, 
 finally assented to the adoption of a line which I indicated, 
 passing between the buildings of the Hospital Schools and 
 
AT GREENWICH OBSERVATORY 1 866 TO 1876. 263 
 
 the public road to Woolwich." "The Galvanic Chro- 
 nometer attached to the S. E. Equatoreal often gave us a 
 great deal of trouble. At last I determined, on the proposal 
 of Mr Ellis, to attempt an extension of Mr R. L. Jones's 
 regulating principle. It is well known that Mr Jones has 
 with great success introduced the system of applying galvanic 
 currents originating in the vibrations of a normal pendulum, 
 not to drive the wheelwork of other clocks, but to regulate to 
 exact agreement the rates of their pendulums which were, 
 independently, nearly in agreement ; each clock being driven 
 by weight-power as before. The same principle is now 
 
 applied to the chronometer The construction is perfectly 
 
 successful ; the chronometer remains in coincidence with the 
 Transit Clock through any length of time, with a small 
 constant error as is required by mechanical theory." "The 
 printed volume of Observations for 1864 has two Appen- 
 dixes; one containing the calculations of the value of the 
 Moon's Semi-diameter deduced from 295 Occupations 
 observed at Cambridge and Greenwich from 1832 to 1860, 
 and shewing that the Occupation Semi-diameter is less 
 than the Telescopic Semi-diameter by 2"; the other con- 
 taining the reduction of the Planetary Observations made at 
 the Royal Observatory in the years 1831 1835 ; filling up 
 the gap, between the Planetary Reductions 1750 1830 made 
 several years ago under my superintendence, and the Reduc- 
 tions contained in the Greenwich Volumes 1836 to the present 
 time : and conducted on the same general principles." " Some 
 trouble had been found in regulating the temperature of the 
 Magnetic Basement, but it was anticipated that in future 
 there would be no difficulty in keeping down the annual vari- 
 ation within about 5 and the diurnal variation within 3. 
 Longitudes in America were determined in this year by way 
 of Valencia and Newfoundland : finished by Nov. I4th." 
 
 Of private history : In April he made a short visit to 
 Ventnor in the Isle of Wight. From June I5th to July 23rd 
 he was on an expedition in Norway with his son Osmund 
 
264 GEORGE BIDDELL AIRY. 
 
 and his nephew Gorell Barnes. There was probably a short 
 stay at Play ford in the winter. 
 
 In this and in the previous year (1865) the free-thinking 
 investigations of Colenso, the Bishop of Natal, had attracted 
 much notice, and had procured him the virulent hostility of a 
 numerous section. His income was withheld from him, and 
 in consequence a subscription fund was raised- for his support 
 by his admirers. Airy, who always took the liberal side in 
 such questions, was a subscriber to the fund, and wrote the 
 following letter to the Bishop : 
 
 ROYAL OBSERVATORY, GREENWICH, S.E., 
 1865, J^y 24- 
 
 MY LORD, 
 
 With many thanks I have to acknowledge your kind 
 recollection of me in sending as a presentation copy the work on 
 Joshua, Judges, and especially on the divided authorship of 
 Genesis ; a work whose investigations, founded in great measure on 
 severe and extensive verbal criticism, will apparently bear com- 
 parison with your Lordship's most remarkable examination of 
 Deuteronomy. I should however not do justice to my own appre- 
 ciation if I did not remark that there are other points considered 
 which have long been matters of interest to me. 
 
 On several matters, some of them important, my present conclu- 
 sions do not absolutely agree with your Lordship's. But I am not 
 the less grateful for the amount of erudition and thought carefully 
 directed to definite points, and above all for the noble example of 
 unwearied research and freedom in stating its consequences, in 
 reference to subjects which scarcely ever occupy the attention of 
 the clergy in our country. 
 
 I am, My Lord, 
 
 Yours very faithfully, 
 
 G. B. AIRY. 
 
 The Lord Bishop of Natal. 
 
 Here also is a letter on the same subject, written to 
 Professor Selwyn, Professor of Divinity at Cambridge : 
 
AT GREENWICH OBSERVATORY 1 866 TO 1 8/6. 265 
 
 ROYAL OBSERVATORY, GREENWICH, 
 LONDON, S.E., 
 
 1866, May 5. 
 
 MY DEAR SIR, 
 
 The MS. concerning Colenso duly arrived. 
 
 I note your remarks on the merits of Colenso. I do not write 
 to tell you that I differ from you, but to tell you why I differ. 
 
 I think that you do not make the proper distinction between a 
 person who invents or introduces a tool, and the person who uses it. 
 
 The most resolute antigravitationist that ever lived might yet 
 acknowledge his debt to Newton for the Method of Prime and 
 Ultimate Ratios and the Principles of Fluxions by which Newton 
 sought to establish gravitation. 
 
 So let it be with Colenso. He has given me a power of tracing 
 out truth to a certain extent which I never could have obtained 
 without him. And for this I am very grateful. 
 
 As to the further employment of this power, you know that he 
 and I use it to totally different purposes. But not the less do I say 
 that I owe to him a new intellectual power. 
 
 I quite agree with you, that the sudden disruption of the old 
 traditional view seems to have unhinged his mind, and to have sent 
 him too far on the other side. I would not give a pin for his 
 judgment. 
 
 Nevertheless, I wish he would go over the three remaining books 
 of the Tetrateuch. 
 
 I know something of Myers, but I should not have thought 
 him likely to produce anything sound on such things as the Hebrew 
 Scriptures. I never saw his " Thoughts." 
 
 I am, my dear Sir, 
 
 Yours very truly, 
 
 G. B. AIRY. 
 
 Professor Selwyn. 
 
 The following letter has reference to Airy's proposal to 
 introduce certain Physico-Mathematical subjects into the 
 Senate-House Examination for B.A. Honors at Cambridge. 
 On various occasions he sharply criticized the Papers set for 
 
266 GEORGE BIDDELL AIRY. 
 
 the Senate-House Examination and the Smith's Prize 
 Examination, and greatly lamented the growing importance 
 of pure mathematics and the comparative exclusion of 
 physical questions in those examinations. His proposal as 
 finally submitted in the letter that follows was somewhat 
 modified (as regards the mode of introducing the subjects) 
 from his original draft, in deference to the opinions of 
 Whewell, Adams, Routh, and other friends to whom he had 
 submitted it. His proposal was favourably received by the 
 Mathematical Board, and recommendations were made in 
 the direction, though not to the extent, that he desired, and 
 he subsequently submitted a Memorandum on those recom- 
 mendations : 
 
 ROYAL OBSERVATORY, GREENWICH, 
 1866, May ii. 
 
 MY DEAR SIR, 
 
 You will perceive, from perusal of the enclosed 
 paper, that I have acted on the permission which you kindly gave 
 me, to transmit to you my proposal for extension of the mathematical 
 education of the University in the Physical direction. 
 
 It is an unavoidable consequence of the structure of the Univer- 
 sity that studies there will have a tendency to take an unpractical 
 form depending much on the personal tastes of special examiners. 
 I trust that, as a person whose long separation from the daily 
 business of the University has enabled him to see in some measure 
 the wants of the external scientific and practical world, I may be 
 forgiven this attempt to bring to the notice of the University my 
 ideas on the points towards which their attention might perhaps 
 be advantageously turned. 
 
 I am, my dear Sir, 
 
 Very faithfully yours, 
 
 G. B. AIRY. 
 
 The Rev. Dr Cartmell, 
 Master of Christ's College 
 and Vice- Chancellor. 
 
AT GREENWICH OBSERVATORY 1 866 TO 1876. 267 
 
 ROYAL OBSERVATORY, GREENWICH, 
 1866, May ii. 
 
 MY DEAR MR VICE-CHANCELLOR, 
 
 About two years ago, by the kindness of the Univer- 
 sity, an opportunity was presented to me of orally stating what I 
 conceived to be deficiencies in the educational course of the 
 University as regards mathematical physics. Since that time, the 
 consideration of those deficiencies, which had long been present to 
 me, has urged itself on my attention with greater force : and finally I 
 have entertained the idea that I might without impropriety com- 
 municate to you my opinion, in a less fugitive form than on the 
 occasion to which I have alluded : with the request that, if you 
 should deem such a course appropriate, you would bring it before 
 the Board of Mathematical Studies, and perhaps ultimately make it 
 known to the Resident Members of the Senate. 
 
 I will first give the list of subjects, which I should wish to see 
 introduced, and to the prosecution of which the generally admirable 
 course of the University is remarkably well adapted : and I will then, 
 without entering into every detail, advert to the process by which I 
 think it probable the introduction of these subjects could be effected. 
 
 In the following list, the first head is purely algebraical, and the 
 second nearly so : but they are closely related to observational 
 science, and to the physical subjects which follow. Some of the 
 subjects which I exhibit on my list are partially, but in my opinion 
 imperfectly, taught at present. I entirely omit from my list Physical 
 Optics, Geometrical Astronomy, and Gravitational Astronomy of 
 Points : because, to the extent to which Academical Education 
 ought to go, I believe that there is no teaching on these sciences 
 comparable to that in the University of Cambridge. (It is, of 
 course, still possible that improvements may be made in the books 
 commonly used.) It might, however, be a question, whether, as 
 regards the time and manner of teaching them, some parts of these 
 subjects might ultimately be associated with the other subjects 
 included in my list. 
 
 I. List of subjects proposed for consideration. 
 
 (i) Partial Differential Equations to the second order, with 
 their arbitrary functions : selected principally with reference to the 
 physical subjects. 
 
268 GEORGE BIDDELL AIRY. 
 
 (2) The Theory of Probabilities as applied to the combination 
 of Observations. 
 
 (3) Mechanics (including Hydraulic Powers) in the state which 
 verges upon practical application, and especially including that part 
 in which the abstract ideas of powe^ and duty occur. 
 
 (4) Attractions. This subject is recognized in the existing 
 course of the University : but, so far as I can infer from examina- 
 tion-papers, it appears to be very lightly passed over. 
 
 (5) The Figure of the Earth, and its consequences, Precession, 
 &c. I believe that the proposal is sanctioned, of adopting some 
 part of this theory in the ordinary course ; but perhaps hardly so far 
 as is desirable. 
 
 (6) The Tides. 
 
 (7) Waves of Water. 
 
 (8) Sound (beginning with Newton's investigation) ; Echoes ; 
 Pipes and Vibrating Strings ; Acoustics ; the Mathematical part of 
 Music. 
 
 (9) Magnetism, terrestrial and experimental, and their 
 connection. 
 
 (I omit for the present Mineralogy and Mathematical Electricity.) 
 This list of subjects appears formidable : but they are in reality 
 
 easy, and would be mastered in a short time by the higher 
 
 Wranglers. 
 
 II. Mode of introducing these subjects into the University. 
 
 After much consideration, and after learning the opinions of 
 several persons whose judgment claims my deepest respect, I 
 propose the gradual introduction of these subjects into the 
 Examination for Honors at admission to the B.A. Degree, as 
 soon as the preparation of Books and the readiness of Examiners 
 shall enable the University to take that step. I conceive that, by a 
 judicious pruning of the somewhat luxuriant growth of Pure Algebra, 
 Analytical Geometry, and Mere Problems, sufficient leisure may be 
 gained for the studies of the undergraduates, and sufficient time for 
 the questions of the examiners. I do not icontemplate that the 
 students could advance very far into the subjects ; but I know the 
 importance of beginning them ; and, judging from the train of 
 thoughts, of reading, and of conversation, among the Bachelors with 
 whom I associated many years ago, I believe that there is quite a 
 sufficient number who will be anxious to go deep into the subjects if 
 they have once entered into them. If six Wranglers annually would 
 
AT GREENWICH OBSERVATORY 1 866 TO 1876. 269 
 
 take them up, my point would be gained. The part which these 
 gentlemen might be expected, in a short time, to take in the govern- 
 ment of the University, would enable them soon to act steadily upon the 
 University course : the efficiency of the University instruction would 
 be increased ; and the external character of the University would be 
 raised. 
 
 The real difficulties, and they are not light ones, would probably 
 be found in providing Examiners and Books. At present, both are 
 wanting within the University. Where there is a great and well- 
 founded objection to intrusting examinations to persons foreign to 
 the University, and where the books have to be created with labour 
 and with absolute outlay of money (for their sale could never be 
 remunerative), the progress must be slow. Still progress would be 
 certain, if the authorities of the University should think the matter 
 deserving of their hearty encouragement. 
 
 Requesting that you and the Members of the University will 
 accept this proposal as an indication of my deep attachment to my 
 University, 
 
 I am, 
 
 My dear Mr Vice- Chancellor, 
 
 Your very faithful servant, 
 
 G. B. AIRY. 
 
 The Rev. Dr Cartmell, 
 &c. &*c. 
 
 Vice- Chancellor of the University of Cambridge. 
 
 1867 
 
 "In this year it was arranged that my Treasury accounts 
 were to be transferred to the Admiralty, making the simplifi- 
 cation which I had so long desired. From the Report to the 
 Visitors it appears that a relic of the Geodetic operations 
 commenced in 1787 for connecting the Observatories of 
 Greenwich and Paris, in the shape of an observing cabin on 
 the roof of the Octagon Room, was shifted and supported in 
 such a manner that the pressure on the flat roof was entirely 
 avoided. With regard to the Transit Circle, the new Colli- 
 mators with telescopes of seven inches aperture had been 
 
2/0 GEORGE BIDDELL AIRY. 
 
 mounted. When the Transit Telescope directed vertically is 
 interposed, the interruptions in the central cube impair the 
 sharpness of definition, still leaving it abundantly good for 
 general use. It had been regarded as probable that the 
 astronomical flexure of the telescope, after cutting away 
 small portions of the central cube, would be found sensibly 
 changed : and this proved to be the case. 1*he difference of 
 flexures of the two ends has been altered more than a second 
 of arc. Referring to a new Portable Altazimuth which had 
 lately been tested, the Report states as follows : ' I may 
 mention that a study of defects in the vertical circle of a 
 small Altazimuth formerly used by me, and an inspection of 
 the operations in the instrument-maker's work-shop, have 
 convinced me that the principal error to be feared in instru- 
 ments of this class is ovality of the graduated limb ; this 
 cannot be eliminated by two microscopes, and such an instru- 
 ment should never be fitted with two only. Our instrument 
 has four.' ' In Osier's Anemometer, a surface of 2 square feet 
 is now exposed to the wind instead of one foot as formerly; 
 and the plate is supported by weak vertical springs instead 
 of rods running on rollers. Its indications are much more 
 delicate than formerly.' 'The Meteors on Nov. I4th were 
 well observed. Eight thousand and three hundred were 
 registered. The variations of frequency at different times 
 were very well noted. The points of divergence were care- 
 fully determined.' Referring to the gradual improvement in 
 the steadiness of chronometers from 1851 to 1866, it appears 
 that from 1851 to 1854 the 'trial number' (which is a com- 
 bination of changes of weekly rate representing the fault of 
 the chronometer) varied from 34-8* to 52'5 S , while from 1862 
 to 1866 it varied from 2T2 S to 2 5 '8 s . The following state- 
 ment will shew the usual steadiness of the Great Clock on 
 the Westminster Palace : On 38 per cent, of days of observa- 
 tion, the clock's error was below I s . On 38 per cent, the 
 error was between I s and 2 s . On 21 per cent, it was between 
 2 s and 3 s . On 2 per cent, between 3 s and 4 s . On i per cent. 
 
AT .GREENWICH OBSERVATORY 1 866 TO 1 8/6. 271 
 
 between 4 s and 5 s . The Report contains an account of the 
 determination of the longitude of Cambridge U.S. by Dr 
 B. A. Gould, by means of galvanic currents through the 
 Atlantic Cable, in the spring of 1867: and advantage was 
 taken of this opportunity for re-determining the longitude of 
 Feagh Main near Valencia in Ireland. The longitude of 
 Feagh Main, found by different methods is as follows : By 
 chronometers in 1844, 4i m 23'23 S ; by galvanic communi- 
 cation with Knight's Town in 1862, 4i m 23'37 s ; by galvanic 
 communication with Foilhommerum in 1866, 4i m 2^'ig s . 
 The collected results for longitude of Cambridge U.S. from 
 different sources are: By moon-culminators (Walker in 1851, 
 and Newcomb in 1862-3), 4 h 44 28'42 S and 4 h 44 m 29'56 S 
 respectively; by Eclipses (Walker in 1851), 4 h 44 29'64 S ; 
 by occultations of Pleiades (Peirce 1838 1842, and 1856 
 1861), 4 h 44 m 29-9 I s and 4 h 44 3O*9O S respectively; by chro- 
 nometers (W. C. Bond in 1851, and G. P. Bond in 1855), 
 4 h 44 m 30'66 S and 4 h 44 3 1 -89 s respectively ; by Atlantic 
 Cable 1866, 4 h 44 3O'99 S . After noticing that many meteor- 
 ological observatories had suddenly sprung up and had com- 
 menced printing their observations in detail, the Report 
 continues thus : ' Whether the effect of this movement will be 
 that millions of useless observations will be added to the 
 millions that already exist, or whether something may be 
 expected to result which will lead to a meteorological theory, 
 I cannot hazard a conjecture. This only I believe, that it 
 will be useless, at present, to attempt a process of mechanical 
 theory; and that all that can be done must be, to connect 
 phaenomena by laws of induction. But the induction must 
 be carried out by numerous and troublesome trials in 
 different directions, the greater part of which would probably 
 be failures.' There was this year an annular eclipse; I 
 made large preparations at the limits of the annularity; 
 failed entirely from very bad weather." In this year Airy 
 contributed a Paper to the Institution of Civil Engineers ' On 
 the use of the Suspension Bridge with stiffened roadway for 
 
2/2 GEORGE BIDDELL AIRY. 
 
 Railway and other Bridges of Great Span,' for which a 
 Telford Medal was awarded to him by the Council of the 
 Institution. And he communicated several Papers to the 
 Royal Society and the Royal Astronomical Society. 
 
 Of private history : There was the usual visit to Playford 
 in January. In April there was a short run to Alnwick and 
 the neighbourhood, in company with Mr anct Mrs Routh. 
 From June 2/th to July 4th he was in Wales with his two 
 eldest sons, visiting Uriconium, &c. on his return. From 
 August 8th to Sept. ;th he spent a holiday in Scotland 
 and the Lake District of Cumberland with his daughter 
 Christabel, visiting the Langtons at Barrow House, near 
 Keswick, and Isaac Fletcher at Tarn Bank. 
 
 In June of this year (1867) Airy was elected an Honorary 
 Fellow of his eld College of Trinity in company with Connop 
 Thirlwall, the Bishop of St David's. They were the first 
 Honorary Fellows elected by the College. The announce- 
 ment was made in a letter from the Master of Trinity (W. H. 
 Thompson), and Airy's reply was as follows : 
 
 ROYAL OBSERVATORY, GREENWICH, 
 LONDON, S.E. 
 
 1867, June i2th. 
 MY DEAR MASTER, 
 
 I am very much gratified by your kind note received 
 this morning, conveying to me the notice that the Master and 
 Sixteen Senior Fellows had elected me, under their new powers, 
 as Honorary Fellow of the College. 
 
 It has always been my wish to maintain a friendly connection 
 with my College, and I am delighted to receive this response from 
 the College. The peculiar form in which the reference to the 
 Statute enables them to put it renders it doubly pleasing. 
 
 As the Statute is new, I should be obliged by a copy of it. And, 
 at any convenient time, I should be glad to know the name of the 
 person with whom I am so honorably associated. 
 
 I am, My dear Master, 
 
 Very faithfully yours, 
 
 G. B. AIRY. 
 
AT GREENWICH OBSERVATORY 1 866 TO 1876. 273 
 
 Consequent on Airy's proposals in 1866 for the introduc- 
 tion of new physical subjects into the Senate-House Ex- 
 amination and his desire that the large number of questions 
 set in Pure Mathematics, or as he termed it "Useless 
 Algebra," should be curtailed, there was a smart and in- 
 teresting correspondence between him and Prof. Cayley, who 
 was the great exponent and advocate of Pure Mathematics at 
 Cambridge. Both of them were men of the highest mathe- 
 matical powers, but diametrically opposed in their views of 
 the use of Mathematics. Airy regarded mathematics as 
 simply a useful machine for the solution of practical problems 
 and arriving at practical results. He had a great respect for 
 Pure Mathematics and all the processes of algebra, so far as 
 they aided him to solve his problems and to arrive at useful 
 results; but he had a positive aversion to mathematical 
 investigations, however skilful and elaborate, for which no 
 immediate practical value could be claimed. Cayley on the 
 contrary regarded mathematics as a useful exercise for the 
 mind, apart from any immediate practical object, and he 
 considered that the general command of mathematics gained 
 by handling abstruse mathematical investigations (though 
 barren in themselves) would be valuable for whatever pur- 
 pose mathematics might be required : he also thought it 
 likely that his researches and advances in the field of 
 Pure Mathematics might facilitate the solution of physical 
 problems and tend to the progress of the practical sciences. 
 Their different views on this subject will be seen from the 
 letters that follow : 
 
 ROYAL OBSERVATORY, GREENWICH, 
 LONDON, S.E. 
 
 1867, Nov. 8. 
 MY DEAR SIR, 
 
 I think it best to put in writing the purport of what I 
 have said, or have intended to say, in reference to the Mathematical 
 Studies in the University. 
 
 First, I will remark on the study of Partial Differential Equations. 
 I do not know that one branch of Pure Mathematics can be con- 
 
 A. B. 18 
 
274 GEORGE BIDDELL AIRY. 
 
 sidered higher than another, except in the utility of the power which 
 it gives. Measured thus, the Partial Differential Equations are very 
 useful and therefore stand very high, as far as the Second Order. 
 They apply, to that point,- in the Jhost important way, to the great 
 problems of nature concerning //;>/<?, and infinite division of ?natter, 
 and space : and are worthy of the most careful study. Beyond that 
 Order they apply to nothing. It was for the purppse of limiting the 
 study to the Second Order, and at the same time working it care- 
 fully, philosophically, and practically, up to that point, that I drew 
 up my little work. 
 
 On the general question of Mathematical Studies, I will first give 
 my leading ideas on what I may call the moral part. I think that a 
 heavy responsibility rests on the persons who influence most strongly 
 the course of education in the University, to direct that course in 
 the way in which it will be most useful to the students in the two 
 ways, of disciplining their powers and habits, and of giving them 
 scientific knowledge of the highest and most accurate order (applying 
 to the phenomena of nature) such as will be useful to them through 
 life. I do not think that the mere personal taste of a teacher is 
 sufficient justification for a special course, unless it has been adopted 
 under a consideration of that responsibility. Now I can say for 
 myself that I have, for some years, inspected the examination 
 papers, and have considered the bearing of the course which they 
 imply upon the education of the student, and am firmly convinced 
 that as regards men below the very few first say below the ten 
 first there is a prodigious loss of time without any permanent good 
 whatever. For the great majority of men, such subjects as abstract 
 Analytical Geometry perish at once. With men like Adams and 
 Stokes they remain, and are advantageous ; but probably there is 
 not a single man (beside them) of their respective years who 
 remembers a bit, or who if he remembers them has the leisure 
 and other opportunities of applying them. 
 
 I believe on the other hand that a careful selection of physical 
 subjects would enable the University to communicate to its students 
 a vast amount of information ; of accurate kind and requiring the 
 most logical treatment ; but so bearing upon the natural phenomena 
 which are constantly before us that it would be felt by every student 
 to possess a real value, that (from that circumstance) it would dwell 
 in his mind, and that it would enable him to correct a great amount 
 of flimsy education in the country, and, so far, to raise the national 
 character. 
 
AT GREENWICH OBSERVATORY 1 866 TO 1 8/6. 275 
 
 The consideration of the education of the reasoning habits sug- 
 gests ideas far from favourable to the existing course. I am old 
 enough to remember the time of mere geometrical processes, and I 
 do not hesitate to say that for the cultivation of accurate mental 
 discipline they were far superior to the operations in vogue at the 
 present day. There is no subject in the world more favourable to 
 logical habit than the Differential Calculus in all its branches if 
 logically worked in its elements : and I think that its applications to 
 various physical subjects, compelling from time to time an attention 
 to the elementary grounds of the Calculus, would be far more 
 advantageous to that logical habit than the simple applications to 
 Pure Equations and Pure Algebraical Geometry now occupying so 
 much attention. 
 
 I am, my dear Sir, 
 
 Yours very truly, 
 
 G. B. AIRY. 
 
 Professor Cayley. 
 
 DEAR SIR,' 
 
 I have been intending to answer your letter of the 8th 
 November. So far as it is (if at all) personal to myself, I would 
 remark that the statutory duty of the Sadlerian Professor is that he 
 shall explain and teach the principles of Pure Mathematics and 
 apply himself to the advancement of the Science. 
 
 As to Partial Differential Equations, they are "high" as being an 
 inverse problem, and perhaps the most difficult inverse problem that 
 has been dealt with. In regard to the limitation of them to the 
 second order, whatever other reasons exist for it, there is also the 
 reason that the theory to this order is as yet so incomplete that there 
 is no inducement to go beyond it ; there could hardly be a more 
 valuable step than anything which would give a notion of the form 
 of the general integral of a Partial Differential Equation of the 
 second order. 
 
 I cannot but differ from you in toto as to the educational value 
 of Analytical Geometry, or I would rather say of Modern Geometry 
 generally. It appears to me that in the Physical Sciences depending 
 on Partial Differential Equations, there is scarcely anything that a 
 student can do for himself: he finds the integral of the ordinary 
 equation for Sound if he wishes to go a step further and integrate 
 
 1 8 2 
 
2/6 GEORGE BIDDELL AIRY. 
 
 the non-linear equation ( ) ~^- = a 2 -j^, he is simply unable to do 
 \dxj dt* dx* 
 
 so ; and so in other cases there is nothing that he can add to what 
 he finds in his books. 'Whereas Geometry (of course to an intel- 
 ligent student) is a real inductive and deductive science of inex- 
 haustible extent, in which he can experiment for himself the very 
 tracing of a curve from its equation (and still more, the consideration 
 of the cases belonging to different values of the parameters) is the 
 construction of a theory to bind together the facts and the selec- 
 tion of a curve or surface proper for the verification of any general 
 theorem is the selection of an experiment in proof or disproof of a 
 theory. 
 
 I do not quite understand your reference to Stokes and Adams, 
 as types of the men who alone retain their abstract Analytical 
 Geometry. If a man when he takes his degree drops mathematics, 
 he drops geometry but if not I think for the above reasons that he 
 is more likely to go on with it than with almost any other subject 
 and any mathematical journal will shew that a very great amount of 
 attention is in fact given to geometry. And the subject is in a very 
 high degree a progressive one ; quite as much as to Physics, one 
 may apply to it the lines, Yet I doubt not thro' the ages one in- 
 creasing purpose runs, and the thoughts of men are widened with the 
 progress of the suns. 
 
 I remain, dear Sir, 
 
 Yours very sincerely, 
 
 A. CAYLEY. 
 CAMBRIDGE, 
 6 Dec., 1867. 
 
 ROYAL OBSERVATORY, GREENWICH, 
 LONDON, S.E. 
 
 1867, December 9. 
 MY DEAR SIR, 
 
 I have received with much pleasure your letter of Decem- 
 ber 6. In this University discussion, I have acted only in public, 
 and have not made private communication to any person whatever 
 till required to do so by private letter addressed to me. Your few 
 words in Queens' Hall seemed to expect a little reply. 
 
AT GREENWICH OBSERVATORY 1 866 TO 1876. 277 
 
 Now as to the Modern Geometry. With your praises of this 
 science as to the room for extension in induction and deduction, 
 &c. ; and with your facts as to the amount of space which it occu- 
 pies in Mathematical Journals ; I entirely agree. And if men, after 
 leaving Cambridge, were designed to shut themselves up in a cavern, 
 they could have nothing better for their subjective amusement. 
 They might have other things as good ; enormous complication and 
 probably beautiful investigation might be found in varying the game 
 of billiards with novel islands on a newly shaped billiard table. But 
 the persons who devote themselves to these subjects do thereby 
 separate themselves from the world. ( They make no step towards 
 natural science or utilitarian science, the two subjects which the 
 world specially desires. The world could go on as well without 
 these separatists. 
 
 Now if these persons lived only for themselves, no other 
 person would have any title to question or remark on their 
 devotion to this barren subject. But a Cambridge Examiner is 
 not in that position. The University is a national body, for 
 education of young men : and the power of a Cambridge Examiner 
 is omnipotent in directing the education of the young men ; 
 and his responsibility to the cause of education is very distinct 
 and very strong. And the question for him to consider is in the 
 sense in which mathematical education is desired by the best authori- 
 ties in the nation, is the course taken by this national institution 
 satisfactory to the nation? 
 
 I express my belief that it is not. satisfactory. I believe that many 
 of the best men of the nation consider that a great deal of time is 
 lost on subjects which they esteem as puerile, and that much of that 
 time might be employed on noble and useful science. 
 
 You may remember that the Commissions which have visited 
 Cambridge originated in a Memorial addressed to the Government 
 by men of respected scientific character : Sabine was one, and I may 
 take him as the representative. He is a man of extensive know- 
 ledge of the application of mathematics as it has been employed for 
 many years in the science of the world ; but he has no profundity of 
 science. He, as I believe, desired to find persons who could enter 
 accurately into mathematical science, and naturally looked to the 
 Great Mathematical University; but he must have been much dis- 
 appointed. So much time is swallowed up by the forced study of 
 the Pure Mathematics that it is not easy to find anybody who can 
 really enter on these subjects in which men of science want assist- 
 
2/8 GEORGE BIDDELL AIRY. 
 
 ance. And so Sabine thought that the Government ought to inter- 
 fere, probably without any clear idea of what they could do. 
 
 I am, my dear Sir, 
 
 Yours very truly, 
 
 G. B. AIRY. 
 
 Professor Cayley. 
 
 DEAR SIR, 
 
 I have to thank you for your last letter. I do not think 
 everything should be subordinated to the educational element : my 
 idea of a University is that of a place for the cultivation of all 
 science. Therefore among other sciences Pure Mathematics; in- 
 cluding whatever is interesting as part of this science. I am bound 
 therefore to admit that your proposed extension of the problem of 
 billiards, if it were found susceptible of interesting mathematical 
 developments, would be a fit subject of study. But in this case I do 
 not think the problem could fairly be objected to as puerile a more 
 legitimate objection would I conceive be its extreme speciality. But 
 this is not an objection that can be brought against Modern Geome- 
 try as a whole : in regard to any particular parts of it which may 
 appear open to such an objection, the question is whether they are 
 or are not, for their own sakes, or their bearing upon other parts of 
 the science to which they belong, worthy of being entered upon and 
 pursued. 
 
 But admitting (as I do not) that Pure Mathematics are only to 
 be studied with a view to Natural and Physical Science, the question 
 still arises how are they best to be studied in that view. I assume 
 and admit that as to a large part of Modern Geometry and of the 
 Theory of Numbers, there is no present probability that these will 
 find any physical applications. But among the remaining parts of 
 Pure Mathematics we have the theory of Elliptic Functions and of 
 the Jacobian and Abelian Functions, and the theory of Differential 
 Equations, including of course Partial Differential Equations. Now 
 taking for instance the problem of three bodies unless this is to be 
 gone on with by the mere improvement in detail of the present 
 approximate methods it is at least conceivable that the future treat- 
 ment of it will be in the direction of the problem of two fixed centres, 
 by means of elliptic functions, &c. ; and that the discovery will be 
 made not by searching for it directly with the mathematical resources 
 
AT GREENWICH OBSERVATORY 1 866 TO 1876. 279 
 
 now at our command, but by "prospecting" for it in the field of 
 these functions. Even improvements in the existing methods are 
 more likely to arise from a study of differential equations in general 
 than from a special one of the equations of the particular problem : 
 the materials for such improvements which exist in the writings of 
 Hamilton, Jacobi, Bertrand, and Bour, have certainly so arisen. 
 And the like remarks would apply to the physical problems which 
 depend on Partial Differential Equations. 
 
 I think that the course of mathematical study at the University 
 is likely to be a better one if regulated with a view to the cultivation 
 of Science, as if for its own sake, rather than directly upon considera- 
 tions of what is educationally best (I mean that the best educational 
 course will be so obtained), and that we have thus a justification for 
 a thorough study of Pure Mathematics. In my own limited expe- 
 rience of examinations, the fault which I find with the men is a want 
 of analytical power, and that whatever else may have been in defect 
 Pure Mathematics has certainly not been in excess. 
 
 I remain, dear Sir, 
 
 Yours sincerely, 
 
 A. CAYLEY. 
 
 CAMBRIDGE, 
 
 loth Dec., 1867. 
 
 1867, December 17. 
 MY DEAR SIR, 
 
 Since receiving your letter of Qth I positively have not 
 had time to express the single remark which I proposed to make 
 on it. 
 
 You state your idea that the educational element ought not to be 
 the predominating element in the University. " I do not think that 
 every thing should be subordinated to the educational element." I 
 cannot conceal my surprise at this sentiment. Assuredly the founders 
 of the Colleges intended them for education (so far as they apply to 
 persons in statu pupillari), the statutes of the University and the 
 Colleges are framed for education, and fathers send their sons to the 
 University for education. If I had not had your words before me, I 
 should have said that it is impossible to doubt this. 
 
 It is much to be desired that Professors and others who exercise 
 no control by force should take every method, not only of promoting 
 
28O GEORGE BIDDELL AIRY. 
 
 science in themselves, but also of placing the promoted science 
 before students : and it is much to be desired that students who 
 have passed the compulsory curriculum should be encouraged to 
 proceed into the novelties which will be most agreeable to them. 
 But this is a totally different thing -from using the Compulsory Force 
 of Examination to drive students in paths traced only by the taste of 
 the examiner. For them, I conceive the obligation to the nation 
 and the duty to follow the national sense on education (as far as it 
 can be gathered from its best representatives) to be undoubted ; and 
 to be, in the intensity of the obligation and duty, most serious. 
 
 I am, my dear Sir, 
 
 Yours very truly, 
 
 G. B. AIRY. 
 Professor Cayley. 
 
 1868 
 
 "In the South-East Dome, the alteration proposed last 
 year for rendering the building fire-proof had been completely 
 carried out The middle room, which was to be appropriated 
 to Chronometers, was being fitted up accordingly. From the 
 Report it appears that 'our subterranean telegraph wires 
 were all broken by one blow, from an accident in the Metro- 
 politan Drainage Works on Croom's Hill, but were speedily 
 repaired.' In my office as Chairman of successive Commis- 
 sions on Standards, I had collected a number of Standards, 
 some of great historical value (as Ramsden's and Roy's 
 Standards of Length, Kater's Scale-beam for weighing great 
 weights, and others), &c. These have been transferred to the 
 newly-created Standards Department of the Board of Trade." 
 In the Report is given a detailed account of the system of 
 preserving and arranging the manuscripts and correspondence 
 of the Observatory, which was always regarded by Airy as a 
 matter of the first importance. From a careful discussion of 
 j the results of observation Mr Stone had concluded that the 
 refractions ought to be diminished, ' Relying on this, we 
 
AT GREENWICH OBSERVATORY 1 866 TO l8/6. 281 
 
 have now computed our mean refractions by diminishing 
 those of Bessel's Fundamenta in the proportion of I to 
 0-99797.' The Magnetometer-Indications for the period 
 1858 1863 had been reduced and discussed, with remarkable 
 results. It is inferred that magnetic disturbances, both solar 
 and lunar, are produced mediately by the Earth, and that the 
 Earth in periods of several years undergoes changes which fit 
 it and unfit it for exercising a powerful mediate action. The 
 Earth-current records had been reduced, and the magnetic 
 effect which the currents would produce had been computed. 
 The result was, that the agreement between the magnetic 
 effects so computed and the magnetic disturbances really 
 recorded by the magnetometers was such as to leave no 
 doubt on the general validity of the explanation of the great 
 storm-disturbances of the magnets as consequences of the 
 galvanic currents through the earth. Referring to the diffi- 
 culty experienced in making the meteorological observations 
 practically available the Report states thus : ' The want of 
 Meteorology, at the present time, is principally in suggestive 
 theory.' In this year Airy communicated to the Royal 
 Astronomical Society a Paper ' On the Preparatory Arrange- 
 ments for the Observation of the Transits of Venus 1874 and 
 1882' : this subject was now well in hand. The First Report 
 of the Commissioners (of whom he was Chairman) appointed 
 to enquire into the condition of the Exchequer Standards 
 was printed : this business took up much time. He was in 
 this year much engaged on the Coinage Commission. 
 
 Of private history : There was the usual winter visit to 
 Playford, and a short visit to Cambridge in June. From 
 about Aug. ist to Sept. 3rd he was travelling in Switzerland 
 with his youngest son and his two youngest daughters. In 
 the course of this journey they visited Zermatt. There had 
 been much rain, the rivers were greatly flooded, and much 
 mischief was done to the roads. During the journey from 
 Visp to Zermatt, near St Nicholas, in a steep part of the 
 gorge, a large stone rolled from the cliffs and knocked their 
 
282 GEORGE BIDDELL AIRY. 
 
 baggage horse over the lower precipice, a fall of several 
 hundred feet. The packages were all burst, and many things 
 were lost, but a good deal was recovered by men suspended 
 by ropes. 
 
 In this year also Airy was busy with the subject of 
 University Examination, which in previous years had occu- 
 pied so much of his attention, as will be seen from the follow- 
 ing letters : 
 
 ROYAL OBSERVATORY, GREENWICH, 
 LONDON, S.E. 
 
 1868, March 12. 
 MY DEAR MASTER, 
 
 I have had the pleasure of corresponding with you on 
 matters of University Examination so frequently that I at once turn 
 to you as the proper person to whom I may address any remarks on 
 that important subject. 
 
 Circumstances have enabled me lately to obtain private informa- 
 tion of a most accurate kind on the late Mathematical Tripos : and 
 among other things, I have received a statement of every individual 
 question answered or partly answered by five honour-men. I have 
 collected the numbers of these in a small table which I enclose. 
 
 I am struck with the almost nugatory character of the five days' 
 honour examination as applied to Senior Optimes, and I do not 
 doubt that it is totally nugatory as applied to Junior Optimes. It 
 appears to me that, for all that depends on these days, the rank of 
 the Optimes is mere matter of chance. 
 
 In the examinations of the Civil Service, the whole number of 
 marks is published, and also the number of marks gained by each 
 candidate. I have none of their papers at hand, but my impression 
 is that the lowest candidates make about i in 3 ; and the fair candi- 
 dates about 2 in 3, instead of i in 10 or i in 13 as our good Senior 
 Optimes. 
 
 I am, my dear Master, 
 
 Very truly yours, 
 
 G. B. AIRY. 
 The Rev. Dr Cookson, 
 
 Master of St Peter's College, 
 
AT GREENWICH OBSERVATORY 1 866 TO 1 8/6. 283 
 
 The Table referred to in the above letter is as follows : 
 
 Number of Questions, and numbers of Answers to Questions as 
 given by several Wranglers and Senior Optimes, in the Examination 
 of Mathematical Tripos for Honours, 1868, January 13, 14, 15, 
 16, 17. 
 
 Number of Questions and Riders in the Printed Papers. 
 
 Questions. Riders. Aggregate. 
 
 In the 10 Papers of the 5 days 123 101 224 
 
 NUMBER OF QUESTIONS AND RIDERS ANSWERED. 
 
 By a Wrangler, between the ist and 
 7th 
 
 Questions. 
 
 6o4 
 
 Riders. 
 
 2=1 
 
 Aggregate. 
 
 QK 
 
 i in 2*36 
 
 By a Wrangler, between the i2th 
 and 2 2 nd 
 
 4 8i 
 
 12* 
 
 6l 
 
 i in 3*68 
 
 By a Wrangler, between the 2 2nd 
 and 32nd 
 
 36 
 
 12* 
 
 4 8i 
 
 i in 4*62 
 
 By a Sen. Opt. between the ist and 
 loth 
 
 171 
 
 
 22* 
 
 i in Q*o5 
 
 By a Sen. Opt. between the roth and 
 
 2Oth 
 
 14! 
 
 2 
 
 16* 
 
 i in 13*60 
 
 
 
 
 
 
 G. B. AIRY. 
 
 1868, March 12. 
 
 ST PETER'S COLLEGE LODGE, CAMBRIDGE, 
 
 March i$th, 1868. 
 MY DEAR SIR, 
 
 I am much obliged by your letter and enclosed paper. 
 
 Any thing done in the last five days by a Junior Optime only 
 shews (generally) that he has been employing some of his time 
 mischievously , for he must have been working at subjects which he is 
 quite unable to master or cramming them by heart on the chance of 
 meeting with a stray question which he may answer. 
 
 The chief part of the Senior Optimes are in something of the 
 same situation. 
 
 I think that the proposed addition of a day to the first part of 
 the Examination, in which "easy questions in physical subjects" 
 may be set, is, on this account, a great improvement. 
 
 Our new Scheme comes on for discussion on Friday next, 
 March 20, at 2 p.m. in the Arts School. It is much opposed by 
 
284 GEORGE BIDDELL AIRY. 
 
 private tutors, examiners and others, and may possibly be thrown out 
 in the Senate this year, though I hope that with a little patience it 
 may be carried, in an unmutilated form, eventually. 
 
 The enclosed Reporton the Srm'th's Prize Examination will be 
 discussed at the same time. 
 
 I will consider what is best to be done on the subject to which 
 your note refers, without delay. With many thanks, 
 
 I am, 
 
 Very faithfully yours, 
 
 H. W. COOKSON. 
 
 The Astronomer Royal. 
 
 In this year certain Members of the Senate of the Uni- 
 versity of Cambridge petitioned Parliament against the aboli- 
 tion of religious declarations required of persons admitted to 
 Fellowships or proceeding to the degree of M.A. The docu- 
 ment was sent to Airy for his signature, and his reply was as 
 follows : 
 
 ROYAL OBSERVATORY, GREENWICH, 
 LONDON, S.E. 
 
 1868, March 18. 
 MY DEAR SIR, 
 
 Though I sympathize to a great extent with the 
 prayer of the petition to Parliament which you sent to me yesterday, 
 and assent to most of the reasons, I do not attach my signature to 
 it, for the following considerations : 
 
 1. I understand, from the introductory clause, and from the 
 unqualified character of the phrase "any such measures" in the 
 second clause, that the petition objects to granting the M.A. degree 
 without religious declaration. I do not see any adequate necessity 
 for this objection, and I cannot join in it. 
 
 2. It appears to me that the Colleges were intended for two 
 collateral objects : instruction by part of the Fellows, on a re- 
 ligious basis ; and support of certain Fellows for scientific pur- 
 poses, without the same ostentatious connection with religion. I 
 like this spirit well, and should be glad to maintain it. 
 
 3. I therefore think (as I have publicly stated before) that the 
 Master of the College ought to be in holy orders ; and so ought 
 
AT GREENWICH OBSERVATORY 1 866 TO 1876. 285 
 
 those of the Fellows who may be expected to be usually resident 
 and to take continuous part in the instruction. But there are many 
 who, upon taking a fellowship, at once lay aside all thoughts of 
 this : and I think that such persons ought not to be trammelled with 
 declarations. 
 
 4. My modification of existing regulations, if it once got into 
 shape, would I dare say be but a small fraction of that proposed 
 by the " measures in contemplation." Still I do not like to join in 
 unqualified resistance to interference in the affairs of the Established 
 Colleges, with that generality of opposition to interference which the 
 petition seems to intimate. 
 
 I agree with articles 3, 4, and 5 ; and I am pleased with the 
 graceful allusion in article 4 to the assistance which has been ren- 
 dered by the Colleges, and by none perhaps so honourably as 
 Trinity, to the parishes connected with it. And I could much 
 wish that the spirit of 3 and 5 could be carried out, with some 
 concession to my ideas in my paragraph 3, above. 
 
 I am, my dear Sir, 
 
 Yours very truly, 
 
 G. B. AIRY. 
 Rev. Dr Lightfoot. 
 
 1869 
 
 From the Report to the Board of Visitors it appears that 
 application had been made for an extension of the grounds 
 of the Observatory to a distance of 100 feet south of the 
 Magnetic Ground, and that a Warrant for the annexation 
 of this space was signed on 1868, Dec. 8. The new Depot 
 for the Printed Productions of the Observatory had been 
 transferred to its position in the new ground, and the founda- 
 tions for the Great Shed were completed. " The courses of 
 our wires for the registration of spontaneous terrestrial gal- 
 vanic currents have been entirely changed. The lines to 
 Croydon and Deptford are abandoned ; and for these are 
 substituted, a line from Angerstein Wharf to Lady Well 
 Station, and a line from North Kent Junction to Morden 
 
286 GEORGE BIDDELL AIRY. 
 
 College Tunnel. At each of these points the communica- 
 tion with Earth is made by a copper plate 2 feet square. 
 The straight line connecting the extreme points of the first 
 station intersects that connecting the two points of the 
 second station, nearly at right angles, and at little distance 
 from the Observatory. The question of dependence of the 
 measurable amount of sidereal aberration upon the thickness 
 of glass or other transparent material in the telescope (a 
 question which involves, theoretically, one of the most deli- 
 cate points in the Undulatory Theory of Light) has lately 
 been agitated on the Continent with much earnestness. I 
 have calculated the curvatures of the lenses of crown and 
 flint glass (the flint being exterior) for correcting spherical 
 and chromatic aberration in a telescope whose tube is filled 
 with water, and have instructed Mr Simms to proceed with 
 the preparation of an instrument carrying such a telescope. 
 I have not finally decided whether to rely on Zenith-distances 
 of 7 Draconis or on right-ascensions of Polaris. In any form 
 the experiment will probably be troublesome. The transit 
 of Mercury on 1868, Nov. 4th, was observed by six ob- 
 servers. The atmospheric conditions were favourable; and 
 the singular appearances usually presented in a planetary 
 transit were well seen. Mr Stone has attached to the South- 
 East Equatoreal a thermo-multiplier, with the view of ex- 
 amining whether heat radiating from the principal stars can 
 be made sensible in our instruments. The results hitherto 
 obtained are encouraging, but they shew clearly that it is 
 vain to attempt this enquiry except in the most superb 
 weather ; and there has not been a night deserving that 
 epithet for some months past. The preparations for ob- 
 serving the Transits of Venus were now begun in earnest. 
 I had come to the conclusion, that after every reliance was 
 placed on foreign and colonial observatories, it would be 
 necessary for the British Government to undertake the 
 equipment of five or six temporary stations. On Feb. I5th 
 I sent a pamphlet on the subject to Mr Childers (First 
 
AT GREENWICH OBSERVATORY 1 866 TO 1876. 287 
 
 Lord of Admiralty), and in April I wrote to the Secretary, 
 asking authority for the purchase of instruments. On June 
 22nd authority is given to me for the instruments: the 
 Treasury assent to 10,500. On August 9th I had pur- 
 chased 3 equatoreals. I have given a short course of Lec- 
 tures in the University of Cambridge on the subject of 
 Magnetism, with the view of introducing that important 
 physical science into the studies of the University. The 
 want of books available to Students, and the novelty of the 
 subject, made the preparation more laborious than the dura- 
 tion of the lectures would seem to imply." In this year 
 there was much work on the Standards Commission, chiefly 
 regarding the suggested abolition of Troy Weight, and 
 several Papers on the subject were prepared by Airy. 
 He also wrote a long and careful description of the Great 
 Equatoreal at Greenwich. 
 
 Of private history: There was the usual visit to Playford 
 in the winter. Mrs Airy was now becoming feebler, and 
 did not now leave Greenwich : since April of this year her 
 letters were written in pencil, and with difficulty, but she 
 still made great efforts to keep up the accustomed corre- 
 spondence. In April Airy went to Cambridge to deliver 
 his lectures on magnetism to the undergraduates : the fol- 
 lowing passage occurs in one of his letters at this time : 
 " I have a mighty attendance (there were 147 names on 
 my board yesterday), and, though the room is large with 
 plenty of benches, I have been obliged to bring in some 
 chairs. The men are exceedingly attentive, and when I 
 look up I am quite struck to see the number of faces 
 staring into mine. I go at 12, and find men at the room 
 copying from my big papers : I lecture from I to 2, and 
 stop till after 3, and through the last hour some men are 
 talking to me and others are copying from the papers ; 
 and I usually leave some men still at work. The men 
 applaud and shew their respect very gracefully. Tfiere 
 are present some two or three persons who attended my 
 
288 GEORGE BIDDELL AIRY. 
 
 former lectures, and they say that I lecture exactly as I 
 did formerly. One of my attendants is a man that they 
 say cannot, from years and infirmity and habit, be induced 
 to go anywhere else: 'Dr Atffrhdall, the Master of Em- 
 manuel. I find that some of my old lecturing habits come 
 again on me. I drink a great deal of cold water, and am 
 very glad to go to bed early." From June loth 3Oth he 
 was travelling in Scotland, and staying at Barrow House 
 near Keswick (the residence of Mr Langton), with his son 
 Hubert. Subsequently, from Aug. i/th to 3ist, he was 
 again in the Lake District, with his daughter Christabel, 
 and was joined there by his son Hubert on the 24th. The 
 first part of the time was spent at Tarn Bank, near Carlisle, 
 the residence of Mr Isaac Fletcher, M.P. From thence he 
 made several expeditions, especially to Barrow in Furness 
 and Seascale, where he witnessed with great interest the 
 Bessemer process of making steel. From Barrow House he 
 made continual excursions among the Cumberland moun- 
 tains, which he knew so well. 
 
 1870 
 
 "In this year Mr Stone, the First Assistant, was appointed 
 to the Cape of Good Hope Observatory, and resigned his 
 post of First Assistant. Mr Christie was appointed in his 
 place. From the Report to the Visitors it appears that 'A 
 few months since we were annoyed by a failure in the 
 illumination of the field of view of the Transit Circle. The 
 reflector was cleaned, but in vain ; at last it was discovered 
 that one of the lenses (the convex lens) of the combination 
 which forms the object-glass of a Reversed Telescope in the 
 interior of the Transit-axis, and through which all illumi- 
 nating light must pass, had become so corroded as to be 
 almost opaque.' The South-East Equatoreal has been 
 partly occupied with the thermo-multiplier employed by Mr 
 Stone for the measure of heat radiating from the principal 
 
AT GREENWICH OBSERVATORY 1 866 TO 1876. 289 
 
 stars. Mr Stone's results for the radiation from Arcturus and 
 a Lyrae appear to be incontrovertible, and to give bases for 
 distinct numerical estimation of the radiant heat of these 
 stars. In my last Report I alluded to a proposed systematic 
 reduction of the meteorological observations during the whole 
 time of their efficient self-registration. Having received from 
 the Admiralty the funds necessary for immediate operations, 
 I have commenced with the photographic registers of the 
 thermometers, dry-bulb and wet-bulb, from 1848 to 1868. 
 Our chronometer-room contains at present 219 chronometers^ 
 including 37 chronometers which have been placed here by 
 chronometer-makers as competing for the honorary reputation 
 and the pecuniary advantages to be derived from success in 
 the half-year's trial to which they are subjected. I take this 
 opportunity of stating that I have uniformly advocated the 
 policy of offering good prices for the chronometers of great 
 excellence, and that I have given much attention to the 
 decision on their merits ; and I am convinced that this 
 system has greatly contributed to the remarkably steady 
 improvement in the performance of chronometers. In the 
 trial which terminated in August 1869, the best chronometers 
 (taking as usual the average of the first six) were superior in 
 merit to those of any preceding year. With the funds placed 
 at my disposal for the Transit of Venus 1874 I purchased 
 three 6-inch equatoreals, and have ordered two : I have also 
 ordered altazimuths (with accurate vertical circles only), and 
 clocks sufficient, as I expect, to equip five stations. For 
 methods of observation, I rely generally on the simple eye- 
 observation, possibly relieved of some of its uncertainty by the 
 use of my colour-correcting eyepiece. But active discussion 
 has taken place on the feasibility of using photographic and 
 spectroscopic methods ; and it will not be easy for some time 
 to announce that the plan of observations is settled. There 
 can be no doubt, I imagine, that the first and necessary duty 
 of the Royal Observatory is to maintain its place well as an 
 Observing Establishment ; and that this must be secured, at 
 A. B. 19 
 
290 GEORGE BIDDELL AIRY. 
 
 whatever sacrifice, if necessary, of other pursuits. Still the 
 question has not unfrequently presented itself to me, whether 
 the duties to which I allude have not, by force of circum- 
 stances, become too exclusive^ and whether the cause of 
 Science might not gain if, as in the Imperial Observatory of 
 Paris for instance, the higher branches of mathematical 
 physics should not take their place by the side of Obser- 
 vatory routine. I have often felt the desire practically to 
 refresh my acquaintance with what were once favourite 
 subjects : Lunar Theory and Physical Optics. But I do not 
 at present clearly see how I can enter upon them with that 
 degree of freedom of thought which is necessary for success 
 in abstruse investigations." 
 
 Of private history : There was a longer visit than usual 
 to Playford, lasting till Jan. 27th. In April he made a short 
 excursion (of less than a week) with his son Hubert to 
 Monmouth, &c. From June I4th to July 2nd he was staying 
 at Barrow House, near Keswick, with his son Hubert : during 
 this time he was much troubled with a painful skin-irritation 
 of his leg and back, which lasted in some degree for a long 
 time afterwards. From Sept. 25th to Oct. 6th he made an 
 excursion with his daughter Christabel to Scarborough, 
 Whitby, &c., and again spent a few days at Barrow 
 House. 
 
 1871 
 
 " In April 1870 the Assistants had applied for an increase 
 of salary, a request which I had urged strongly upon the 
 Admiralty. On Jan. 27 of this year the Admiralty answered 
 that, on account of Mr Childers's illness, the consideration 
 must be deferred to next year ! The Assistants wrote 
 bitterly to me : and with my sanction they wrote to the 
 First Lord. On Jan. 3ist I requested an interview with Mr 
 Baxter (secretary of the Admiralty), and saw him on 
 Feb. 3rd, when I obtained his consent to an addition of 
 
AT GREENWICH OBSERVATORY 1 866 TO 1876. 291 
 
 ,530. There was still a difficulty with the Treasury, but 
 on June 27th the liberal scale was allowed. Experiments 
 made by Mr Stone shew clearly that a local elevation, like 
 that of the Royal Observatory on the hill of Greenwich Park, 
 has no tendency to diminish the effect of railway tremors. 
 The correction for level error in the Transit Circle having 
 become inconveniently large, a sheet of very thin paper, 
 Y|Q inch in thickness, was placed under the eastern Y, which 
 was raised from its bed for the purpose. The mean annual 
 value of the level-error appears to be now sensibly zero. As 
 the siege and war operations in Paris seriously interfered 
 with the observations of small planets made at the Paris 
 Observatory, observations of them were continued at Green- 
 wich throughout each entire lunation during the investment 
 of the city. The new Water-Telescope has been got into 
 working order, and performs most satisfactorily. Obser- 
 vations of 7 Draconis have been made with it, when the star 
 passed between 2O h - and I7 h -, with some observations for 
 adjustment at a still more advanced time. As the astro- 
 nomical latitude of the place of observation is not known, the 
 bearing of these observations on the question of aberration 
 cannot be certainly pronounced until the autumn observations 
 shall have been made ; but supposing the geodetic latitude 
 to be accordant with the astronomical latitude, the result for 
 aberration appears to be sensibly the same as with ordinary 
 telescopes. Several years since, I prepared a barometer, by 
 which the barometric fluctuations were enlarged, for the 
 information of the public ; its indications are exhibited on the 
 wall, near to the entrance gate of the Observatory. A card 
 is now also exhibited, in a glass case near the public 
 barometer, giving the highest and lowest readings of the 
 thermometer in the preceding twenty-four hours. Those 
 who have given attention to the history of Terrestrial 
 Magnetism are aware that Halley's Magnetic Chart is very 
 frequently cited ; but I could not learn that any person, at 
 least in modern times, had seen it. At last I discovered a 
 
 19 2 
 
2Q2 GEORGE BIDDELL AIRY. 
 
 copy in the library of the British Museum, and have been 
 allowed to take copies by photolithography. These are 
 appended to the Magnetical and Meteorological Volume for 
 1869. The trials and certificates of hand-telescopes for the 
 use of the Royal Navy have lately been so frequent that they 
 almost become a regular part of the work of the Observatory. 
 I may state here that by availing myself of a theory of 
 eyepieces which I published long since in the Cambridge 
 Transactions, I have been able to effect a considerable im- 
 provement in the telescopes furnished to the Admiralty. 
 The occurrence of the Total Eclipse of the Sun in December 
 last has brought much labour upon the Observatory. As 
 regards the assistants and computers, the actual observation 
 on a complicated plan with the Great Equatoreal (a plan for 
 which few equatoreals are sufficiently steady, but which when 
 properly carried out gives a most complete solution of the 
 geometrical problem) has required, in observation and in 
 computation, a large expenditure of time. My preparations 
 for the Transit of Venus have respect only to eye-observation 
 of contact of limbs. With all the liabilities and defects to 
 which it is subject, this method possesses the inestimable 
 advantage of placing no reliance on instrumental scales. I 
 hope that the error of observation may not exceed four 
 seconds of time, corresponding to about ex 13" of arc. I shall 
 be very glad to see, in a detailed form, a plan for making the 
 proper measures by heliometric or photographic apparatus; 
 and should take great interest in combining these with the 
 eye-observations, if my selected stations can be made avail- 
 able. But my present impression is one of doubt on the 
 certainty of equality of parts in the scale employed. An 
 error depending on this cause could not be diminished by 
 any repetition of observations." After referring to the desira- 
 bility of vigorously prosecuting the Meteorological Reductions 
 (already begun) and of discussing the Magnetic Observations, 
 the Report concludes thus : " There is another consideration 
 which very often presents itself to my mind; the waste of 
 
AT GREENWICH OBSERVATORY 1 866 TO 1876. 293 
 
 labour in the repetition of observations at different observa- 
 tories I think that this consideration ought not to be 
 
 put out of sight in planning the courses of different Obser- 
 vatories." In this year De Launay's Lunar Theory was 
 published. This valuable work was of great service to Airy 
 in the preparation of the Numerical Lunar Theory, which he 
 subsequently undertook. In the latter part of this year Airy 
 was elected President of the Royal Society, and held the 
 office during 1872 and 1873. At this time he was much 
 pressed with work, and could ill afford to take up additional 
 duties, as the following quotation from a letter to one of his 
 friends shews : " The election to the Presidency of R. S. is 
 flattering, and has brought to me the friendly remembrances of 
 many persons ; but in its material and laborious connections, 
 I could well have dispensed with it, and should have done so 
 but for the respectful way in which it was pressed on me." 
 
 Of private history : There was the usual winter visit to 
 Playford. In April he made a short trip to Cornwall with 
 his daughter Annot. In June he was appointed a Companion 
 of the Bath, and was presented at Court on his appointment. 
 Mrs Airy was staying with her daughter, Mrs Routh, at 
 Hunstanton, during June, her state of health being somewhat 
 improved. From August 1st to 28th he was chiefly in 
 Cumberland, at Barrow House, and at Grange, Borrowdale, 
 where his son Osmund was staying for a holiday. 
 
 1872 
 
 " From the Report to the Board of Visitors it appears 
 that ' The Normal Sidereal Clock for giving sidereal time by 
 galvanic communication to the Astronomical Observatory 
 was established in the Magnetic Basement in 1871, June; 
 that locality being adapted for it on account of the uniformity 
 of temperature, the daily changes of temperature rarely ex- 
 ceeding i Fahrenheit. Its escapement is one which I sug- 
 
294 GEORGE BIDDELL AIRY. 
 
 gested many years ago in the Cambridge Transactions; a 
 detached escapement, very closely analogous to the ordinary 
 chronometer escapement, the pendulum receiving an impulse 
 only at alternate vibrations... /the steadiness of rate is very 
 far superior to any that we have previously attained.' The 
 aspect of railway enterprise is at present favourable to the 
 Park and to the Observatory. The South-Eastern Railway 
 Company has made an arrangement with the Metropolitan 
 Board of Works for shifting the course of the great Southern 
 Outfall Sewer. This enables the Company to trace a new 
 line for the railway, passing on the north side of London 
 Street, at such a distance from the Observatory as to remove 
 all cause of alarm. I understand that the Bill, which was 
 unopposed, has passed the Committee of the House of 
 Commons. I trust that the contest, which has lasted thirty- 
 seven years, is now terminated. The observations of 7 Dra- 
 conis with the Water-Telescope, made in the autumn of 1871, 
 and the spring of 1872, are reduced, the latter only in their 
 first steps.... Using the values of the level scales as determined 
 by Mr Simms (which I have no reason to believe to be inac- 
 curate) the spring and autumn observations of 1871 abso- 
 lutely negative the idea of any effect being produced on the 
 constant of aberration by the amount of refracting medium 
 traversed by the light. The great Aurora of 1872 Feb. 4 
 was well observed. On this occasion the term Borealis would 
 have been a misnomer, for the phenomenon began in the 
 South and was most conspicuous in the South. Three times 
 in the evening it exhibited that umbrella-like appearance 
 which has been called (perhaps inaccurately) a corona. I 
 have very carefully compared its momentary phenomena 
 with the corresponding movements of the magnetometers. In 
 some of the most critical times, the comparison fails on ac- 
 count of the violent movements and consequent faint traces 
 of the magnetometers. I have not been able to connect the 
 phases of aurora and those of magnetic disturbance very 
 distinctly. The Report contains a detailed account of the 
 
AT GREENWICH OBSERVATORY 1 866 TO 1876. 2Q5 
 
 heavy preparations for the observation of the Transit of 
 Venus 1874, including the portable buildings for the instru- 
 ments, the instruments themselves (being a transit-instru- 
 ment, an altazimuth, and an equatoreal, for each station), 
 and first class and second-class clocks, all sufficient for the 
 equipment of 5 stations, and continues thus: I was made 
 aware of the assent of the Government to the wish of the 
 Board of Visitors, as expressed at their last meeting, that 
 provision should be made for the application of photography 
 to the observation of the Transit of Venus. It is unnecessary 
 for me to remark that our hope of success is founded entirely 
 on our confidence in Mr De La Rue. Under his direction, 
 Mr Dallmeyer has advanced far in the preparation of five 
 photoheliographs....The subject is recognized by many as- 
 tronomers as not wholly free from difficulties, but it is 
 generally believed that these difficulties may be overcome, 
 and Mr De La Rue is giving careful attention to the most 
 important of them. I take this opportunity of reporting to 
 the Board that the Observatory was honoured by a visit of 
 His Majesty the Emperor of Brazil, who minutely examined 
 every part." After referring to various subjects which in his 
 opinion might be usefully pursued systematically at the 
 Observatory, the Report proceeds thus : " ' The character of 
 the Observatory would be somewhat changed by this inno- 
 vation, but not, as I imagine, in a direction to which any 
 objection can be made. It would become, pro tanto, a 
 physical observatory ; and possibly in time its operations 
 might be extended still further in a physical direction.' The 
 consideration of possible changes in the future of the Obser- 
 vatory leads me to the recollection of actual changes in the 
 past. In my Annual Reports to the Visitors I have en- 
 deavoured to chronicle these ; but still there will be many 
 circumstances which at present are known only to myself, 
 but which ought not to be beyond the reach of history. I 
 have therefore lately employed some time in drawing up a 
 series of skeleton annals of the Observatory (which unavoid- 
 
296 GEORGE BIDDELL AIRY. 
 
 ably partakes in some measure of the form of biography), 
 and have carried it through the critical period, 1836 1851. 
 If I should command sufficient leisure to bring it down to 
 1861, 1 think that I might then ytry well stop." (The skeleton 
 annals here referred to are undoubtedly the manuscript notes 
 which form the basis of the present biography. Ed.) " On 
 Feb. 23rd in this year I first (privately) formed the notion of 
 preparing a numerical Lunar Theory by substituting De- 
 launay's numbers in the proper Equations and seeing what 
 would come of it." 
 
 Of private history : There was the usual visit to Playford 
 in this year later than usual from Feb. 4th to Mar. 4th. 
 The letters written during this visit are, as usual, full of 
 freshness and delight at finding himself in his favourite 
 country village. On June 5th he went to Barrow House, 
 near Keswick, to be present at the marriage of his second 
 son Hubert to Miss S. C. Langton, daughter of Z. Langton 
 Esq., of Barrow House. After the wedding he made a trip 
 through the Trossachs district of Scotland with his daughter 
 Annot, and returned to Greenwich on June i/th. 
 
 On the 26th June 1872 Airy was appointed a Knight 
 Commander of the Most Honourable Order of the Bath : he 
 was knighted by the Queen at Osborne on the 3Oth of July. 
 In the course of his official career he had three times been 
 offered Knighthood, and had each time declined it : but it 
 seemed now as if his scruples on the subject were removed, 
 and it is probable that he felt gratified by the public recog- 
 nition of his services. Of course the occasion produced 
 many letters of congratulation from his friends : to one 
 of these he replied as follows : " The real charm of these 
 public compliments seems to be, that they excite the 
 sympathies and elicit the kind expressions of private friends 
 or of official superiors as well as subordinates. In every 
 way I have derived pleasure from these." From the As- 
 sistants of the Royal Observatory he received a hearty letter 
 of congratulation containing the following paragraph. " Our 
 
AT GREENWICH OBSERVATORY 1 866 TO 1876. 297 
 
 position has naturally given us peculiar opportunities for 
 perceiving the high and broad purposes which have charac- 
 terized your many and great undertakings, and of witnessing 
 the untiring zeal and self-denial with which they have been 
 pursued." 
 
 On the 1 8th of March 1872 Airy was nominated a Foreign 
 Associate of the Institut de France, to fill the place vacant 
 by the death of Sir John Herschel. The following letter of 
 acknowledgment shews how much he was gratified by this 
 high scientific honour : 
 
 ROYAL OBSERVATORY, GREENWICH, 
 1872, March 23. 
 
 A Messieurs 
 
 Messieurs ELIE DE BEAUMONT, 
 
 et J. B. DUMAS, 
 Secretaires perpetuels de I'Academie 
 
 des Sciences, Institut de France. 
 
 GENTLEMEN, 
 
 I am honoured with your letter of March 18, communi- 
 cating to me my nomination by the Academy of Sciences to the 
 place rendered vacant in the class of Foreign Associates of the 
 Academy by the decease of Sir John Herschel, and enclosing Copy 
 of the Decree of the President of the French Republic approving the 
 Election. 
 
 It is almost unnecessary for me to attempt to express to you the 
 pride and gratification with which I receive this announcement. By 
 universal consent, the title of Associe Etranger de V Academic des 
 Sciences is recognised as the highest distinction to which any man of 
 science can aspire ; and I can scarcely imagine that, unless by the 
 flattering interpretation of my friends in the Academy, I am entitled 
 to bear it. But in any case, I am delighted to feel that the bands of 
 friendship are drawn closer between myself and the distinguished 
 body whom, partly by personal intercourse, partly by correspondence, 
 and in every instance by reputation, I have known so long. 
 
298 GEORGE BIDDELL AIRY. 
 
 I beg that you will convey to the Academy my long-felt esteem 
 for that body in its scientific capacity, and my deep recognition of 
 its friendship to me and of the honor which it has conferred on me 
 in the late election. ^ 
 
 I have' the honor to be 
 
 Gentlemen, 
 Your very faithful servant, 
 
 G. B. AIRY. 
 
 On the 2Oth November 1872 Airy was nominated a 
 Grand Cross in the Imperial Order of the Rose of Brazil : 
 the insignia of the Order were accompanied by an autograph 
 letter from the Emperor of Brazil, of which the following is a 
 transcript. 
 
 MONSIEUR, 
 
 Vous etes un des doyens de la science, et le President de 
 1'illustre Societe, qui a eu la bienveillance d'inscrire mon nom parmi 
 ceux de ses associe's. La maniere, dont vous m'avez fait les hon- 
 neurs de votre Observatoire m'a impose aussi 1'agreable devoir 
 d'indiquer votre nom a 1'empereur de Bresil pour un temoignage de 
 haute estime, dont je suis fort heureux de vous faire part personelle- 
 ment, en vous envoyant les decorations que vous garderez, au moins, 
 comme un souvenir de ma visite a Greenwich. 
 
 J'espere que vous m'informerez, quand il vous sera aise, des 
 travaux de votre observatoire, et surtout de ce que Ton aura fait 
 pour 1'observation du passage de Venus et la de'termination exacte 
 de la passage. 
 
 J'ai re$u deja les Proceedings de la Royal Society lesquels m'inte- 
 ressent vivement. 
 
 Je voudrais vous e'crire dans votre langue, mais, comme je n'en 
 ai pas 1'habitude, j'ai craigne de ne pas vous exprimer tout-a-fait les 
 sentiments de 
 
 Votre affectionne, 
 
 D. PEDRO D'ALCANTARA. 
 Rio, 
 
 22 Octobre, 1872. 
 
AT GREENWICH OBSERVATORY 1 866 TO 1876. 299 
 
 Airy's reply was as follows : 
 
 ROYAL OBSERVATORY, GREENWICH, 
 
 1872, November 26. 
 SIRE, 
 
 I am honoured with your Imperial Majesty's autograph letter 
 of October 22 informing me that, on considering the attention which 
 the Royal Society of London had been able to offer to your Majesty, 
 as well as the explanation of the various parts of the establishment of 
 this Observatory which I had the honor and the high gratification to 
 communicate, You had been pleased to place my name in the 
 Imperial Order of the Rose, and to present to me the Decorations of 
 Grand Cross of that Order. 
 
 With pride I receive this proof of Your Majesty's recollection of 
 your visit to the scientific institutions of Great Britain. 
 
 The Diploma of the appointment to the Order of the Rose, 
 under the Imperial Sign Manual, together with the Decorations of 
 the Order, have been transmitted to me by his Excellency Don 
 Pereira de Andrada, Your Majesty's Representative at the British 
 Court. 
 
 Your Majesty has been pleased to advert to the approaching 
 Transit of Venus, on the preparations for which you found me 
 engaged. It is unfortunate that the Transit of 1874 will not be 
 visible at Rio de Janeiro. For that of 1882, Rio will be a favourable 
 position, and we reckon on the observations to be made there. Your 
 Majesty may be assured that I shall loyally bear in mind your desire 
 to be informed of any remarkable enterprise of this Observatory, or 
 of any principal step in the preparations for the Transit of Venus 
 and of its results. 
 
 I have the honor to be 
 Sire, 
 Your Imperial Majesty's very faithful servant, 
 
 G. B. AIRY. 
 To His Majesty 
 
 The Emperor of Brazil. 
 
 Airy's old friend, Adam Sedgwick, was now very aged 
 and infirm, but his spirit was still vigorous, and he was warm- 
 hearted as ever. The following letter from him (probably the 
 
300 GEORGE BIDDELL AIRY. 
 
 last of their long correspondence) was written in this year, 
 and appears characteristic : 
 
 TRINITY COLLEGE, CAMBRIDGE, 
 
 May 10, 1872. 
 MY DEAR AIRY, 
 
 I have received your card of invitation for the ist of June, 
 and with great joy should I count upon that day if 1 thought that I 
 should be able to accept your invitation : but alas I have no hope 
 of the kind, for that humiliating malady which now has fastened 
 upon me for a full year and a half has not let go its hold, nor is it 
 likely to do so. A man who is journeying in the 88th year of his 
 pilgrimage is not likely to throw off such a chronic malady. Indeed 
 were I well enough to come I am deaf as a post and half blind, and 
 if I were with you I should only be able to play dummy. Several 
 years have passed away since I was last at your Visitation and I had 
 great joy in seeing Mrs Airy and some lady friends at the Obser- 
 vatory, but I could not then attend the dinner. At that Meeting 
 were many faces that I knew, but strangely altered by the rude 
 handling of old Time, and there were many new faces which I had 
 never seen before at a Royal Society Meeting ; but worse than all, 
 all the old faces were away. In vain I looked round for Wollaston, 
 Davy, Davies Gilbert, Barrow, Troughton, &c. &c. ; and the merry 
 companion Admiral Smyth was also away, so that my last visit had 
 its sorrowful side. But why should I bother you with these old 
 man's mopings. 
 
 I send an old man's blessing and an old man's love to all the 
 members of your family ; especially to Mrs Airy, the oldest and 
 dearest of my lady friends. 
 
 I remain, my dear Airy, 
 
 Your true-hearted old friend, 
 
 his 
 
 ADAM X SEDGWICK. 
 mark 
 
 P.S. Shall I ever again gaze with wonder and delight from the 
 great window of your Observatory, 
 
 The body of the above letter is in the handwriting of an 
 amanuensis, but the signature and Postscript are in Sedgwick's 
 handwriting. (Ed.) 
 
AT GREENWICH OBSERVATORY 1 866 TO 1876. 301 
 
 1873 
 
 " Chronographic registration having been established at 
 the Paris Observatory, Mr Hilgard, principal officer of the 
 American Coast Survey, has made use of it for determining 
 the longitude of Harvard from Greenwich, through Paris, 
 Brest, and St Pierre. For this purpose Mr Hilgard's Transit 
 Instrument was planted in the Magnetic Court. I understand 
 that the result does not sensibly differ from that obtained by 
 Mr Gould, through Valentia and Newfoundland. It was 
 known to the scientific world that several of the original 
 thermometers, constructed by Mr Sheepshanks (in the course 
 of his preparation of the National Standard of Length) by 
 independent calibration of the bores, and independent deter- 
 mination of the freezing and boiling points on arbitrary 
 graduations, were still preserved at the Royal Observatory. 
 It was lately stated to me by M. Tresca, the principal officer 
 of the International Metrical Commission, that, in the late 
 unhappy war in Paris, the French original thermometers were 
 destroyed ; and M. Tresca requested that, if possible, some of 
 the original thermometers made by Mr Sheepshanks might 
 be appropriated to the use of the International Commission. 
 I have therefore transferred to M. Tresca the three ther- 
 mometers A. 6, S. I, S. 2, with the documentary information 
 relating to them, which was found in Mr Sheepshanks's 
 papers ; retaining six thermometers of the same class in the 
 Royal Observatory. The Sidereal Standard Clock continues 
 to give great satisfaction. I am considering (with the aid of 
 Mr Buckney, of the firm of E. Dent and Co.) an arrangement 
 for barometric correction, founded on the principle of action 
 on the pendulum by means of a magnet which can be raised 
 or lowered by the agency of a large barometer. The Altazi- 
 muth has received some important alterations. An examina- 
 tion of the results of observations had made me dissatisfied 
 
302 GEORGE BIDDELL AIRY. 
 
 with the bearings of the horizontal pivots in their Y's. Mr 
 Simms, at my request, changed the bearings in Y's for bearing 
 in segments of circles, a construction which has worked 
 admirably well in the pivots of the Transit Circle." (And in 
 various other respects the instrument appears to have received 
 a thorough overhauling. Ed.) ''With the consent of the Royal 
 Society and of the Kew Committee, the Kew fieliograph has 
 been planted in the new dome looking over the South Ground. 
 It is not yet finally adjusted. Some magnetic observations 
 in the Britannia and Conway tubular bridges were made last 
 autumn. For this purpose I detached an Assistant (Mr Car- 
 penter), who was aided by Capt. Tupman, R.M.A. ; in other 
 respects the enterprise was private and at private expense. 
 The rates of the first six chronometers (in the annual trials) 
 are published, in a form which appears most likely to lead to 
 examination of the causes that influence their merits or 
 demerits. This report is extensively distributed to British 
 and Foreign horologists and instrument-makers. All these 
 artists appear to entertain the conviction that the careful 
 comparisons made at this Observatory, and the orderly form 
 of their publication, have contributed powerfully to the im- 
 provement of chronometers. Very lately, application has 
 been made to me, through the Board of Trade, for plans and 
 other information regarding time-signal-balls, to assist in 
 guiding the authorities of the German Empire in the estab- 
 lishment of time signals at various ports of that State. In 
 other foreign countries the system is extending, and is referred 
 to Greenwich as its origin. The arrangements and prepara- 
 tions for the observation of the Transit of Venus occupied 
 much attention. With regard to the photoheliographs it is 
 proposed to make trial of a plan proposed by M. Janssen, for 
 numerous photographs of Venus when very near to the Sun's 
 limb. On Apr. 26th the engaging of photographic teachers 
 was sanctioned. Observers were selected and engaged. A 
 working model of the Transit was prepared, and the use of 
 De La Rue's Scale was practised. There was some hostile 
 
AT GREENWICH OBSERVATORY 1 866 TO 1 876. 303 
 
 criticism of the stations selected for the observation of the 
 Transit, which necessitated a formal reply. Reference is 
 made to the increase of facilities for making magnetical and 
 meteorological observations. The inevitable result of it. is, 
 that observations are produced in numbers so great that 
 complete reduction becomes almost impossible. The labour 
 of reduction is very great, and it is concluded that, of the 
 enormous number of meteorological observations now made 
 at numerous observatories, very few can ever possess the 
 smallest utility. Referring to my Numerical Lunar Theory : 
 on June 3Oth, 1873, a theory was formed, nearly but not per- 
 fectly complete. Numerical development of powers of a -r r 
 and r -r- a. Factors of corrections to Delaunay first attempted, 
 but entirely in numerical form." In March of this year Airy 
 was consulted by Mr W. H. Barlow, C.E., and Mr Thomas 
 Bouch (the Engineer of the Tay Bridge, which was blown 
 down in 1879, and of a proposed scheme for a Forth Bridge 
 in 1873) on the subject of the wind pressure, &c., that should 
 be allowed for in the construction of the bridge. Airy's 
 report on this question is dated 1873, Apr. Qth: it was subse- 
 quently much referred to at the Official Enquiry into the 
 causes of the failure of the Tay Bridge. At the end of this 
 year Airy resigned the Presidency of the Royal Society. In 
 his Address to the Society on Dec. ist he stated his reasons 
 in full, as follows : " the seventy of official duties, which seem 
 to increase, while vigour to discharge them does not increase ; 
 and the distance of my residence.... Another cause is a diffi- 
 culty of hearing, which unfits me for effective action as Chair- 
 man of Council. " 
 
 Of private history : There was the usual visit to Play- 
 ford in January : also a short visit in May : and a third visit 
 at Christmas. There was a short run in June, of about a 
 week, to Coniston, with one of his daughters. And there was 
 a trip to Weymouth, &c., for about 10 days, with one of his 
 daughters, in the beginning of August. On his return from 
 the last-mentioned trip, Airy found a letter from the Secretary 
 
304 GEORGE BIDDELL AIRY. 
 
 of the Swedish Legation, enclosing the Warrant under the 
 Royal Sign Manual of His Majesty (Oscar), the King of 
 Sweden and Norway, by which he was nominated as a First 
 Class Commander of the Order of the North Star, and accom- 
 panying the Decorations of that Order. 
 
 1874 
 
 "In this year Mr Glaisher resigned his appointment: I 
 placed his Department (Magnetical and Meteorological) 
 under Mr Ellis. A balance of peculiar construction has been 
 made by Mr Oertling, from my instructions, and fixed near 
 the public barometer at the Entrance Gate. This instrument 
 enables the public to test any ordinary pound weight, shewing 
 on a scale the number of grains by which it is too heavy or 
 too light. Fresh counterpoises have been attached to the 
 Great Equatoreal to balance the additional weight of the new 
 Spectroscope, which was finally received from Mr Browning's 
 / hands on May 2nd of the present year. The Spectroscope is 
 specifically adapted to sweeping round the Sun's limb, with a 
 view to mapping out the prominences, and is also available 
 for work on Stars and Nebulae, the dispersive power being 
 very readily varied. An induction-coil, capable of giving a 
 six-inch spark, has been made for this instrument by Mr 
 Browning. Some new classes of reductions of the meteoro- 
 logical observations from 1848 to 1868 have been undertaken 
 and completed in the past year. The general state of this 
 work is as follows : The diurnal changes of the dry-bulb 
 thermometer, as depending on the month, on the temperature 
 waves, on the barometric waves, on the overcast and cloudless 
 states of the sky, and on the direction of the wind, have been 
 computed and examined for the whole period ; and the exhi- 
 bition of the results is ready for press. The similar reductions 
 for the wet-bulb thermometer are rapidly approaching com- 
 pletion. Regarding the preparations for the Transit of Venus 
 
AT GREENWICH OBSERVATORY 1 866 TO 1876. 305 
 
 Expeditions. Originally five stations were selected and fully 
 equipped with equatoreals, transits, altazimuths, photohelio- 
 graphs, and clocks ; but I have since thought it desirable to 
 supplement these by two branch stations in the Sandwich 
 Islands and one in Kerguelen's Island ; and the additional 
 instruments thus required have been borrowed from various 
 sources, so that there is now an abundant supply of instru- 
 mental means.... There will thus be available for observation 
 of the Transit of Venus 23 telescopes, nine of which will be 
 provided with double-image-micrometers ; and five photo- 
 heliographs ; and for determination of local time, and latitude 
 and longitude, there will be nine transits and six altazimuths. 
 ...All the observers have undergone a course of training in 
 photography ; first, under a professional photographer, Mr 
 Reynolds, and subsequently under Capt Abney, R.E., whose 
 new dry-plate process is to be adopted at all the British 
 Stations.... A Janssen slide, capable of taking 50 photographs 
 of Venus and the neighbouring part of the Sun's limb at 
 intervals of one second, has been made by Mr Dallmeyer for 
 each of the five photoheliographs." Attached to the Report 
 to the Visitors is a copy of the Instructions to Observers 
 engaged in the Transit of Venus Expeditions, prepared with 
 great care and in remarkable detail. " In the past spring I 
 published in the Monthly Notices of the Royal Astronomical 
 Society a statement of the fundamental points in a new 
 treatment of the Lunar Theory, by which, availing myself of 
 all that has been done in the best algebraical investigations 
 of that theory, I trust to be able by numerical operations 
 only to give greater accuracy to final results. Considerable 
 progress has been made in the extensive numerical develop- 
 ments, the work being done, at my private expense, entirely 
 by a junior computer; and I hope, at any rate, to put it in 
 such a state that there will be no liability to its entire loss. 
 When this was reported to the Board of Visitors, it was 
 resolved on the motion of Prof. Stokes, that this work, as a 
 public expense, ought to be borne by the Government ; and 
 
 A. B. 2O 
 
306 GEORGE BIDDELL AIRY. 
 
 this was forwarded to the Admiralty. On June 24th I wrote 
 to the Secretary of the Admiralty, asking for 100 for the 
 present year, which after the usual enquiries and explanations 
 was sanctioned on Aug. 29th." f 
 
 Of private history : There were short visits to Playford 
 in January, June, and October, but only for a few days in 
 each case. In March there was a run of two or three days to 
 Newnham (on the Severn) to see the Bore on the Severn, 
 and to Malvern. In July he went to Newcastle to observe 
 with Mr Newall's great telescope, but the weather was un- 
 favourable : he then went on to Barrow House near Keswick, 
 and spent a few days there, with excursions among the 
 mountains. On Aug. I3th he went with his daughter Christ- 
 abel to the Isle of Arran, and then by Glasgow to the 
 Trosachs, where he made several excursions to verify the 
 localities mentioned in the " Lady of the Lake." While in 
 Scotland he heard of the death of his brother, the Rev. 
 William Airy, and travelled to Keysoe in Bedfordshire to 
 attend the funeral ; and returned to Greenwich on Aug. 24th. 
 
 1875 
 
 " In October of this year I wrote to the Admiralty that 
 I had grounds for asking for an increase of my salary: be- 
 cause the pension which had been settled on my wife, and 
 which I had practically recognized as part of my salary, had 
 been terminated by her death ; so that my salary now stood 
 lower by ^200 than that of the Director of Studies of the 
 Royal Naval College. The Admiralty reply favourably, and 
 on Nov. 2/th the Treasury raise my salary to .1,200. For 
 the service of the Clock Movement of the Great Equatoreal, 
 a water-cistern has been established in the highest part of 
 the Ball-Turret, the necessity for which arose from the fol- 
 lowing circumstance : The Water Clock was supplied by a 
 small pipe, about 80 feet in length, connected with the 
 
AT GREENWICH OBSERVATORY 1 866 TO 1876. 307 
 
 3-inch Observatory main (which passes through the Park), 
 at a distance of about 250 feet from any other branch pipe. 
 In spite of this distance I have seen that, on stopping the 
 water-tap in the Battery-Basement under the North-East 
 Turret, the pressure in the gauge of the Water Clock has 
 been instantly increased by more than 40 Ibs. per square 
 inch. The consequent derangement of the Water Clock in 
 its now incessant daily use became intolerable. Since the 
 independent supply was provided, its performance has been 
 most satisfactory. With the Spectroscope the solar pro- 
 minences have been mapped on 28 days only; but the 
 weather of the past winter was exceptionally unfavour- 
 able for this class of observation. After mapping the pro- 
 minences, as seen on the C line, the other lines, especially 
 F and b, have been regularly examined, whenever prac- 
 ticable. Great care has been taken in determining the 
 position, angle, and heights of the prominences in all cases. 
 The spectrum of Coggia's Comet was examined at every 
 available opportunity last July, and compared directly with 
 that of carbon dioxide, the bands of the two spectra being 
 sensibly coincident. Fifty-four measures of the displacement 
 of lines in the spectra of 10 stars, as compared with the 
 corresponding lines in the spectra of terrestrial elements 
 (chiefly hydrogen), have been made, but some of these ap- 
 pear to be affected by a constant error depending on faulty 
 adjustment of the Spectroscope. Photographs of the Sun 
 have been taken with the Kew Photoheliograph on 186 
 days ; and of these 377 have been selected for preservation. 
 The Moon, Jupiter, Saturn, and several stars (including the 
 Pleiades and some double stars) have been photographed 
 with the Great Equatoreal, with fairly satisfactory results, 
 though further practice is required in this class of work. 
 I would mention a supplemental mechanism which I have 
 myself introduced into some chronometers. I have long 
 remarked that, in ordinary good chronometers, the freedom 
 from irregularities depending on mechanical causes is most 
 
 20 2 
 
308 GEORGE BIDDELL AIRY. 
 
 remarkable ; but that, after all the efforts of the most ju- 
 dicious makers, there is in nearly every case a perceptible 
 defect of thermal compensation. There is great difficulty 
 in correcting the residual faulfcf not only because an incon- 
 ceivably small movement of the weights on the balance-curve 
 is required, but also because it endangers the equilibrium 
 of the balance. The mechanism adopted to remedy the 
 defect is described in a Paper in the Horological Journal of 
 July 1875 by Mr W. Ellis, and has received the approval of 
 some able chronometer-makers. With respect to the Transit 
 of Venus Expeditions : The parties from Egypt and Rod- 
 riguez are returned. I am in continual expectation of the 
 arrival of the other parties. I believe the eye-observations 
 and the ordinary photographs to be quite successful ; I 
 doubt the advantage of the Janssen ; one of the double- 
 image-micrometers seems to have failed ; and the Zenith- 
 telescope gives some trouble. At three stations at Rodri- 
 guez, and three at Kerguelen, the observations appear to 
 have been most successful. At the Sandwich Islands, two 
 of the stations appear to have been perfectly successful 
 (except that I fear that the Janssen has failed), and a rich 
 series of lunar observations for longitude is obtained. At 
 New Zealand, I grieve to say, the observations were totally 
 lost, entirely in consequence of bad weather. There has been 
 little annoyance from the dreaded ' black drop.' Greater 
 inconvenience and doubt have been caused by the unex- 
 pected luminous ring round Venus. With regard to the 
 progress of my proposed New Lunar Theory: Three com- 
 puters are now steadily employed on the work. It will be 
 remembered that the detail and mass of this work are 
 purely numerical ; every numerical coefficient being accom- 
 panied with a symbolical correction whose value will some- 
 times depend on the time, but in every case is ultimately 
 to be obtained in a numerical form. Of these coefficients, 
 extracted (for convenience) from Delaunay's results, there 
 are 100 for parallax, 182 for longitude, 142 for latitude; 
 
AT GREENWICH OBSERVATORY 1 866 TO 1876. 309 
 
 the arguments being preserved in the usual form." After 
 reviewing the changes that had taken place at the Ob- 
 servatory during the past forty years, the Report to the 
 Board of Visitors concludes thus : " I much desire to see the 
 system of time-signals extended, by clocks or daily signals, 
 to various parts of our great cities and our dockyards, and 
 above all by hourly signals on the Start Point, which I 
 believe would be the greatest of all benefits to nautical 
 chronometry. Should any extension of our scientific work 
 ever be contemplated, I would remark that the Observatory 
 is not the place for new physical investigations. It is well 
 adapted for following out any which, originating with pri- 
 vate investigators, have been reduced to laws susceptible of 
 verification by daily observation. The National Observa- 
 tory will, I trust, always remain on the site where it was 
 first planted, and which early acquired the name" of 'Flam- 
 steed Hill.' There are some inconveniences in the position, 
 arising principally from the limited extent of the hill, but 
 they are, in my opinion, very far overbalanced by its ad- 
 vantages." In a letter on the subject of the Smith's Prizes 
 Examination at Cambridge, which was always a matter of 
 the greatest interest to him, Airy renewed his objections to 
 the preponderance in the Papers of a class of Pure Mathe- 
 matics, which he considered was never likely under any 
 circumstances to give the slightest assistance to Physics. 
 And, as before, these remarks called forth a rejoinder from 
 Prof. Cayley, who was responsible for many of the ques- 
 tions of the class referred to. In this year Airy completed 
 his " Notes on the Earlier Hebrew Scriptures," which were 
 shortly afterwards published as a book by Messrs Longmans, 
 Green, & Co. In his letter to the publishers introducing the 
 subject, he says, " For many years past I have at times put 
 together a few sentences explanatory as I conceive of the 
 geographical and historical circumstances connected with the 
 principal events recorded in the Hebrew Scriptures. The 
 view which I take is free, but I trust not irreverent. They 
 
310 GEORGE BIDDELL AIRY. 
 
 terminate with a brief review of Colenso's great work. 
 The collection now amounts to a small book." From the 
 references already given in previous years to his Papers 
 and correspondence on the/" geography of Exodus, his 
 correspondence with Colenso, &c. &c., it will be seen 
 that he took a great interest in the early history of the 
 Israelites. On August loth, 1875, Airy celebrated the Bi- 
 centenary of the Royal Observatory by a dinner in the 
 Octagon Room, which was attended by the Presidents of 
 the Royal Society and the R. Astr. Society, and by a large 
 number of Scientific gentlemen interested in Astronomy. 
 In February he was revising his Treatise on " Probabilities." 
 
 Of private history: up to Jan. i6th Airy was at Playford 
 as usual. For about a week in April he was in the Isle 
 of Man with .his daughter Christabel. In June there was 
 a short trip to Salisbury, Blandford, and Wimborne. On 
 August 1 2th he started with his daughter Annot for a holi- 
 day in Cumberland, but on the next day he was recalled 
 by a telegram with the intelligence that a change for the 
 worse had come over his wife's health. Lady Airy died 
 on August 1 3th, 1875. For the last five years of her life 
 she had been very helpless from the effects of a paralytic 
 stroke a very sad ending to a bright and happy life and 
 had been continually nursed throughout this time by her 
 two unmarried daughters with the greatest self-denial and 
 devotion. Her husband had been unremitting in his care 
 and attention. Nothing was wanting that the most thought- 
 ful kindness could supply. And in all his trips and ex- 
 cursions his constant and kind letters shewed how anxious 
 he was that she should participate in all his interests and 
 amusements. From the nature of the case it could hardly 
 be said that her death was unexpected, and he received the 
 shock with the manly steadiness which belonged to him. 
 Lady Airy was buried in Playford churchyard. From Sept. 
 22nd to Oct. 4 he made a short expedition to Wales (Capel 
 Curig, &c.). On Dec. i$th he attended the Commemoration 
 
AT GREENWICH OBSERVATORY 1 866 TO 1876. 311 
 
 at Trinity College, Cambridge. On Dec. 22nd he went as 
 usual to Playford. 
 
 In this year Airy received the high honour of the Free- 
 dom of the City of London, in the following communica- 
 tion : 
 
 STONE, Mayor. A Common Council holden in the Chamber of 
 the Guildhall of the City of London, on Thursday the 2gih day of 
 April 1875. 
 
 Resolved Unanimously 
 
 That the Freedom of this City in a Gold Box 
 of the value of One hundred guineas be presented to Sir George 
 Biddell Airy, K.C.B., D.C.L., LL.D. &c., Astronomer Royal, as a 
 recognition of his indefatigable labours in Astronomy, and of his 
 eminent services in the advancement of practical science, whereby 
 he has so materially benefited the cause of Commerce and Civiliza- 
 tion. 
 
 MONCKTON. 
 
 This Resolution was forwarded with a letter from Ben- 
 jamin Scott, the Chamberlain. Airy's reply was as follows : 
 
 ROYAL OBSERVATORY, GREENWICH, S.E. 
 1875, May i. 
 
 DEAR SIR, 
 
 I have the honour to acknowledge your letter of April 30, 
 accompanied with Copy of the Resolution of the Common Council 
 of the City of London passed at their Meeting of April 29, under 
 signature of the Town Clerk, That the Freedom of the City of 
 London in a valuable Box be presented to me, in recognition of 
 works stated in the Resolution. And I am requested by you to 
 inform you whether it is my intention to accept the compliment 
 proposed by the Corporation. 
 
 In reply, I beg you to convey to the Right Honorable the Lord 
 Mayor and the Corporation that I accept with the greatest pride 
 and pleasure the honour which they propose to offer to me. The 
 Freedom of our Great City, conferred by the spontaneous act of 
 
312 GEORGE BIDDELL AIRY. 
 
 its Municipal Governors, is in my estimation the highest honour 
 which it is possible to receive ; and its presentation at this time is 
 peculiarly grateful to me. 
 
 I have the honour ftb be, 
 Sir, 
 Your very obedienjj servant, 
 
 G. B. AIRY. 
 Benjamin Scott, Esq., 
 
 drv. &c. &c. 
 Chamberlain of the Corporation of the 
 City of London. 
 
 As it was technically necessary that a Freeman of the 
 City of London should belong to one or other of the City 
 Companies, the Worshipful Company of Spectacle Makers 
 through their clerk (with very great appropriateness) en- 
 quired whether it would be agreeable that that Company 
 should have the privilege of conferring their Honorary Free- 
 dom on him, and added: "In soliciting your acquiescence 
 to the proposal I am directed to call attention to the fact 
 that this Guild is permitted to claim all manufacturers of 
 Mathematical and Astronomical Instruments within the City 
 of London, which is now pleaded as an apology for the wish 
 that one so distinguished as yourself in the use of such In- 
 struments should be enrolled as a Member of this Craft." 
 In his reply, accepting the Freedom of the Company, Airy 
 wrote thus : " I shall much value the association with a body 
 whose ostensible title bears so close a relation to the official 
 engagements which have long occupied me. I have had ex- 
 tensive experience both in arranging and in using optical 
 and mathematical instruments, and feel that my own pur- 
 suits are closely connected with the original employments 
 of the Company." The Freedom of the Company was duly 
 presented, and the occasion was celebrated by a banquet at 
 the Albion Tavern on Tuesday, July 6th. 
 
 The Freedom of the City of London was conferred at 
 
AT GREENWICH OBSERVATORY 1 866 TO 1 876. 313 
 
 a Court of Common Council held at the Guildhall on 
 Thursday the 4th of November. In presenting the gold 
 box containing the Freedom, the Chamberlain, in an elo- 
 quent speech, first referred to the fact that this was the 
 first occasion on which the Freedom had been conferred 
 on a person whose name was associated with the sciences 
 other than those of war and statecraft. He then referred 
 to the solid character of his work, in that, while others had 
 turned their attention to the more attractive fields of ex- 
 ploration, the discovery of new worlds or of novel celestial 
 phenomena, he had incessantly devoted himself to the less 
 interesting, less obtrusive, but more valuable walks of prac- 
 tical astronomy. And he instanced as the special grounds 
 of the honour conferred, the compilation of nautical tables 
 of extraordinary accuracy, the improvement of chronometers, 
 the correction of the compasses of iron ships, the restoration 
 of the standards of length and weight, and the Transit of 
 Venus Expeditions. In his reply Airy stated that he re- 
 garded the honour just conferred upon him as the greatest 
 and proudest ever received by him. He referred to the fact 
 that the same honour had been previously conferred on the 
 valued friend of his youth, Thomas Clarkson, and said that 
 the circumstance of his succeeding such a man was to him- 
 self a great honour and pleasure. He alluded to his having 
 received a small exhibition from one of the London Com- 
 panies, when he was a poor undergraduate at Cambridge, 
 and acknowledged the great assistance that it had been to 
 him. With regard to his occupation, he said that he had 
 followed it in a great measure because of its practical use, 
 and thought it fortunate that from the first he was con- 
 nected with an institution in which utility was combined 
 with science. The occasion of this presentation was cele- 
 brated by a Banquet at the Mansion House on Saturday 
 July 3rd, 1875, to Sir George Airy (Astronomer Royal) and 
 the Representatives of Learned Societies. 
 
 There is no doubt that Airy was extremely gratified 
 
314 GEORGE BIDDELL AIRY. 
 
 by the honour that he had received. It was to him the 
 crowning honour of his life, and coming last of all it threw 
 all his other honours into the shade. To his independent 
 and liberal spirit there' was something peculiarly touching 
 in the unsolicited approbation and act of so powerful and 
 disinterested a body as the Corporation of the City of London. 
 
CHAPTER IX. 
 
 AT GREENWICH OBSERVATORY FROM JANUARY IST, 1876, 
 TO HIS RESIGNATION OF OFFICE ON AUGUST ISTH, 
 1881. 
 
 1876 
 
 "AT the door from the Front Court to the staircase of the 
 Octagon Room (the original entrance to the Observatory as 
 erected by Sir Christopher Wren), a small porch-shelter has 
 been often desired. I proposed to fix there a fan-roof of 
 quadrantal form, covering the upper flat stone of the external 
 steps. On a critical examination of the micrometer-screws 
 of the Transit Circle it was found that the corrections, which 
 range from 1*38" to + 076", indicate considerable wear in 
 the screws ; and it was found that as much as one-hundreth 
 part of an inch had been worn away from some of the 
 threads. The old screws were consequently discarded, and 
 new ones were made by Mr Simms. The adjustment of the 
 Spectroscope has occupied a great deal of attention. There 
 was astigmatism of the prisms ; and false light reflected from 
 the base of the prisms, causing loss both of light and of 
 definition. The latter defect was corrected by altering the 
 angles, and then astigmatism was corrected by a cylindrical 
 lens near the slit. The definition in both planes was then 
 found to be perfect. The number of small planets has now 
 become so great, and the interest of establishing the elements 
 of all their orbits so small, while at the same time the light 
 of all those lately discovered is very faint, and the difficulty 
 
3l6 GEORGE BIDDELL AIRY. 
 
 and doubt of observation greatly increased, that I have 
 begun to think seriously of limiting future observations to a 
 small number of these objects. All observations with the 
 Spectroscope have been completely reduced ; the measures of 
 lines in the spectra of elements being converted into corre- 
 sponding wave-lengths, and the observations, of displacement 
 of lines in the spectra of stars being reduced so as to exhibit 
 the concluded motion in miles per second, after applying a 
 correction for the earth's motion. Sixteen measures of the 
 F line in the spectrum of the Moon as compared with 
 hydrogen give a displacement corresponding to a motion of 
 less than two miles a second, which seems to shew that the 
 method of comparison now adopted is free from systematic 
 error ; and this is supported by the manner in which motions 
 of approach and recession are distributed among the stars 
 examined on each night of observation. The results recently 
 obtained appear to be on the whole as consistent as can be 
 expected in such delicate observations, and they support in a 
 remarkable manner the conclusions of Dr Huggins, with 
 regard to the motions of those stars which he examined. 
 Photographs of the sun have been taken with the photo- 
 heliograph on 182 days. On one of the photographs, which 
 was accidentally exposed while the drop slit was being drawn 
 up, there appears to be a faint image of a cloud-like promi- 
 nence close to the sun's limb, though the exposure probably 
 only amounted to a fraction of a second. A prominence of 
 unusual brilliancy was seen with the Spectroscope about the 
 same time and in the same position with reference to the 
 Sun's limb. All groups of Sun-spots and faculae have been 
 numbered, and the dates of their first and last appearances 
 entered up to the present time. Areas of spots have been 
 measured, and the measures have been reduced to millionths 
 of the Sun's visible hemisphere. The examination of the 
 readings of the deep-sunk thermometers from 1846 to 1873 
 has exhibited some laws which had been sufficiently estab- 
 lished before this time, and some which were less known. 
 
AT GREENWICH OBSERVATORY 1876 TO l88l. 317 
 
 Among the former were the successive retardations of seasons 
 in successive descents, amounting to about four months at the 
 depth of 25 feet ; and the successive diminutions of the annual 
 range of temperature. Among the latter is the character of 
 the changes from year to year, which the great length of this 
 series of observations brings well to light. It is found that 
 from year to year the mean temperature of the surface for 
 the year, varying by three or four degrees of Fahrenheit, 
 follows in its changes the mean temperature of the atmosphere 
 for the year, and that the changes of annual temperature are 
 propagated downwards, retarded in phase and diminishing in 
 amount of change, in the same manner (though probably not 
 following the same law) as the season changes. The inference 
 from this is, that changes of temperature come entirely from 
 the exterior and in no discoverable degree from the interior ; 
 an inference which may be important in regard both to solar 
 action and to geology. Referring to the Transit of Venus 
 observations : In the astronomical part of the reductions, 
 there has been great labour and difficulty in the determina- 
 tion of local sidereal times ; some books of observations 
 required extensive transcription ; some instrumental errors 
 are still uncertain ; the latter determinations have perplexed 
 us so much that we are inclined to believe that, in spite of the 
 great facilities of reduction given by the transit instrument, it 
 would be better to rely on the altazimuth for time-determina- 
 tions In the photographic part, I have confined my 
 
 attention entirely to measures of the distance between the 
 centres of the Sun and Planet, a troublesome and complex 
 operation. Referring to the progress of the Numerical Lunar 
 Theory: With a repetition of grant from the Treasury, I have 
 usually maintained four junior computers on this work. The 
 progress, though considerable, has not been so great as I had 
 hoped, by reason of the excessive personal pressure upon me 
 during the whole year. I wrote a letter of congratulation to 
 Le Verrier on the completion of his great work of Planetary 
 Tables. On May I3th the Queen was at South Kensington, 
 
318 GEORGE BIDDELL AIRY. 
 
 and I attended to explain the astronomical instruments, and 
 shewed Her Majesty one of the Transit of Venus photo- 
 graphs." 
 
 Of private history : He returned from his Playford visit 
 on the 1 8th of January. In April there was a two-day trip 
 to Colchester. From June I3th to July 1 2th he was travelling 
 in the North of Scotland and the Orkneys with his daughters, 
 staying for a short time with Mr Webster, M.P., at Aberdeen, 
 and with Mr Newall at Newcastle. In September there was 
 a week's run to Birkenhead and Keswick. In November a 
 week's run to Playford. From the I3th to i$th of December 
 he was at Cambridge, and on the 28th he went to Playford 
 for the usual winter stay there. 
 
 1877 
 
 " In April of this year I was much engaged on the subject 
 of Mr Gill's expedition to Ascension to observe for the deter- 
 mination of the parallax of Mars at the approaching opposition 
 of that planet. A large Direct-vision Spectroscope has been 
 quite recently made by Mr Hilger under Mr Christie's 
 direction on a new plan, in which either great dispersion or 
 great purity of spectrum is obtained by the use of ' Half- 
 prisms/ according as the incident pencil falls first on the 
 perpendicular or on the oblique face. In this Spectroscope 
 either one or two half prisms can be used at pleasure, 
 according to the dispersion required, and there is facility 
 for increasing the train to three or four half-prisms, though 
 the dispersion with two only is nearly double of that given 
 by the large ten-prism Spectroscope. The definition in this 
 form of Spectroscope appears to be very fine. At the end of 
 May 1876, spectroscopic determinations of the Sun's rotation 
 were made by observations of the relative displacement of 
 the Fraunhofer lines at the east and west limbs respectively. 
 The results are in close agreement with the value of the 
 rotation found from observations of Sun-spots. A similar 
 
AT GREENWICH OBSERVATORY 1876 TO 1 88 1. 319 
 
 determination has also been made in the case of Jupiter, with 
 equally satisfactory results. An Electrometer on Sir William 
 Thomson's plan, for continuous photographic registration of 
 atmospheric electricity has been received from Mr White of 
 Glasgow. It was mounted in December. The computation 
 of the photographic records of the barometer from 1854 to 
 1873 has so far advanced that we can assert positively that 
 there is no trace of lunar tide in the atmosphere ; but that 
 there is a strongly marked semi-diurnal solar tide, accom- 
 panied with a smaller diurnal tide. We are at present 
 engaged in comparing the barometric measures with the 
 directions of the wind. Regarding the distribution of the 
 printed observations : There is no extensive wish for separate 
 magnetic observations, but general magnetic results are in 
 great demand, especially for mining operations, and to meet 
 this a map of magnetic declination is furnished in the news- 
 paper called the ' Colliery Guardian.' As regards the opera- 
 tions for the Transit of Venus : The computing staff has by 
 degrees been reduced to two junior computers within the 
 Observatory ; and one or two computers external to the 
 Observatory, who are employed on large groups of systematic 
 calculations. The principal part of the calculations remaining 
 at the date of the last Report was that applying to the deter- 
 mination of the geographical longitudes of fundamental 
 stations. At the moment of my writing, the last of these 
 (the longitude of Observatory Bay, Kerguelen) is not abso- 
 lutely finished: The method of determining the geo- 
 graphical longitude of the principal station in each group by 
 vertical transits of the Moon has been found very successful 
 at Honolulu and Rodriguez. For stations in high south 
 latitude, horizontal transits are preferable. As regards the 
 Numerical Lunar Theory: With the view of preserving, 
 against the ordinary chances of destruction or abandonment, 
 a work which is already one of considerable magnitude, I 
 have prepared and have printed as Appendix to the Green- 
 wich Observations (with additional copies as for a separate 
 
32O GEORGE BIDDELL AIRY. 
 
 work) the ordinary Equations of Lunar Disturbance, the 
 novel theory of Symbolical Variations, and the Numerical 
 Developments of the quantities on the first side of the 
 Equations. At various times from February to May I was 
 engaged on the reduction of Malta Tides, and on a Paper 
 concerning the same. In July I was awarded the Albert 
 Medal for my Compass corrections, and received the same 
 from the Prince of Wales. In February, Campbell's instru- 
 ment for the registration of sunshine was introduced : it was 
 mounted in July." 
 
 Of private history: "I was at Playford until Jan. iQth, in 
 close correspondence as usual with Mr Christie at the Obser- 
 vatory, and attending to my Numerical Lunar Theory. 
 From Mar. 2Qth to Apr. 2nd I went on a short trip to Here- 
 ford, Worcester, &c. From June 8th to 2Oth I was at 
 Playford. From Aug. I3th to Sept. 8th Airy was on an 
 expedition in Ireland, chiefly in the North and West, with 
 his daughters. When at Dublin he visited Grubb's instru- 
 ment factory. On the return journey he stayed for some 
 time in the Lake District of Cumberland, and took soundings 
 in the neighbourhood of the place of the ' floating island ' in 
 Derwentwater." 
 
 Airy took the greatest interest in antiquarian matters, 
 whether military or ecclesiastical, and his feelings on such 
 matters is well illustrated by the following letter : 
 
 ROYAL OBSERVATORY, GREENWICH, S.E. 
 1877, February 27. 
 
 DEAR SIR, 
 
 I venture to ask if you can assist me in the following 
 matter. 
 
 In the Parish Church of Playford, near Ipswich, Suffolk, was a 
 splendid brass tombstone to -Sir Thomas Felbrigg. By an act of 
 folly and barbarism, almost unequalled in the history of the world, 
 the Incumbent and Curate nearly destroyed the brass inscription 
 surrounding the image of the Knight. 
 
AT GREENWICH OBSERVATORY 1876 TO 1 88 1. 321 
 
 This tombstone is figured in Cough's Sepulchral Antiquities, 
 which, I presume, is to be found in the British Museum. 
 
 And I take the liberty to ask if you would kindly look at the 
 engraving, and give me any suggestion as to the way in which some 
 copies of it could be made, in a fairly durable form. I am connected 
 with the parish of Playford, and am anxious to preserve for it this 
 memorial of a family of high rank formerly resident there. 
 
 I am, dear Sir, 
 
 Very faithfully yours, 
 
 G. B. AIRY. 
 T. Winter Jones, Esq. 
 
 To this request Mr Winter Jones immediately acceded, 
 and the engraving was duly photographed, and copies were 
 circulated with a historical notice of Sir George (not Sir 
 Thomas) Felbrigg and a history of the Monument. Sir 
 George Felbrigg was Esquire-at-Arms to Edward III., and 
 Lord of the Manor of Playford : he died in 1400, and was 
 buried in the North wall of Playford Church. 
 
 1878 
 
 The Report to the Board of Visitors has this paragraph : 
 " I continue to remark the approaching necessity for Library 
 extension. Without having absolutely decided on a site, I 
 may suggest that I should wish to erect a brick building, 
 about 50 feet by 20, consisting of two very low stones (or 
 rather of one story with a gallery running round its walls), so 
 low that books can be moved by hand without necessity for a 
 ladder. In the month of December, 1877, the azimuthal 
 error of the Transit Circle had increased to 10". A skilful 
 workman, instructed by Mr Simms, easily reduced the error 
 to about 2" *5 (which would leave its mean error nearly o), 
 the western Y being moved to the north so far as to reduce 
 the reading of the transit micrometer, when pointed to the 
 south, from 3 5 r> 500 to 35 r> ooo. The level error was not sen- 
 sibly affected. The Sidereal Standard Clock preserves a rate 
 
 A. B. 21 
 
322 GEORGE BIDDELL AIRY. 
 
 approaching to perfection, so long as it is left without dis- 
 turbance of the galvanic-contact springs (touched by its pen- 
 dulum), which transmit signals at every second of time to 
 sympathetic clocks and the chronograph. A readjustment 
 of these springs usually disturbs the rate. To facilitate the 
 observations of stars, a new working catalogue has been 
 prepared, in which are included all stars down to the third 
 magnitude, stars down to the fifth magnitude which have not 
 been observed in the last two catalogues, and a list of 258 
 stars of about the sixth magnitude of which the places are 
 required for the United States Coast Survey. The whole 
 number of stars in our new working list is about 2500. It 
 may be here mentioned that an extensive series of observa- 
 tions was made, during the autumn, of about 70 stars, at the 
 request of Mr Gill, for comparison with Mars, Ariadne, and 
 Melpomene. On Apr. loth last, a very heavy fall of rain 
 took place. Between Apr. lod. 5h. and Apr. lid. 2h., 
 2*824 inch. was recorded, and 75 per cent, of this, or 2*12 inch., 
 fell in the eight hours between 13! h. and 21 J h. ; and on 
 May 7, I inch of rain fell in 50 minutes, of which J inch fell 
 in 15 minutes. The supplementary compensation continues 
 to be applied with success to Government chronometers 
 which offer facilities for its introduction, and a marked im- 
 provement in the performance of chronometers returned after 
 repair by the makers appears to have resulted from the 
 increased attention now given to the compensation. Of the 
 29 competitive chronometers, 25 have the supplementary 
 compensation." With regard to the reduction of the observa- 
 tions of the Transit of Venus : After reference to the diffi- 
 culties arising from the errors and the interpretation of the 
 language used by some of the observers, the Report con- 
 tinues thus : "Finally a Report was made to the Government 
 on July 5th, giving as the mean result for Mean Solar 
 Parallax 8" "76"; the results from ingress and from egress, 
 however, differing to the extent of o"*i I.... After further 
 examination and consideration, the result for parallax has 
 
AT GREENWICH OBSERVATORY 1876 TO l88l. 323 
 
 been increased to 8"' 82 or 8"'83. The results from photo- 
 graphy have disappointed me much. The failure has arisen, 
 perhaps sometimes from irregularity of limb, or from atmo- 
 spheric distortion, but more frequently from faintness and 
 from want of clear definition. Many photographs, which to 
 the eye appeared good, lost all strength and sharpness when 
 placed under the measuring microscope. A final result 8"' 17 
 was obtained from Mr Burton's measures, and 8"*o8 from 
 Capt. Tupman's. With regard to the Numerical Lunar 
 Theory : A cursory collection of the terms relating to the 
 Areas (in the Ecliptic) led me to suppose that there might 
 be some error in the computations of the Annual Equation 
 and related terms. A most jealous re-examination has how- 
 ever detected nothing, and has confirmed my belief in the 
 general accuracy of the numerical computations. I dare not 
 yet venture to assume an error in Delaunay's theory; but I 
 remember that the Annual Equation gave great trouble to 
 the late Sir John Lubbock, and that he more than once 
 changed his conclusions as to its true value. In February I 
 was engaged on the drawings and preparations for my 
 intended Lecture at Cockermouth on the probable condition 
 of the interior of the Earth. The Lecture was delivered in 
 April. At different times in the autumn I was engaged on 
 diagrams to illustrate the passage of rays through eye-pieces 
 and double-image micrometers. The miscellaneous scientific 
 correspondence, which was always going on, was in this year 
 unusually varied and heavy." 
 
 Of private history : He was at Playford till Jan. 26th. 
 In April he went to Cockermouth to deliver his Lecture 
 above-mentioned : the journey was by Birmingham, where 
 he stayed for two days (probably with his son Osmund, who 
 resided there), to Tarn Bank (the residence of Isaac Fletcher, 
 M.P.) : the lecture was delivered on the 22nd : he made 
 excursions to Thirlmere and Barrow, and to Edward I.'s 
 Monument, and returned to Greenwich on the 27th. From 
 June 1 7th to 28th he was at Playford. From Aug. igth to 
 
 21 2 
 
324 GEORGE BIDDELL AIRY. 
 
 Sept. 1 7th he was travelling in Scotland, visiting the Tay 
 Bridge, the Loch Katrine Waterworks, &c., and spent the 
 last fortnight of his .trip at Portinscale, near Keswick. On 
 Dec. 23rd he went to Playforct. 
 
 1879 
 
 " The manuscripts of every kind, which are accumulated 
 in the ordinary transactions of the Observatory, are preserved 
 with the same care and arranged on the same system as 
 heretofore. The total number of bound volumes exceeds 
 4000. Besides these there is the great mass of Transit of 
 Venus reductions and manuscripts, which when bound may 
 be expected to form about 200 volumes. With regard to the 
 numerous group of Minor Planets, the Berlin authorities have 
 most kindly given attention to my representation, and we 
 have now a most admirable and comprehensive Ephemeris. 
 But the extreme faintness of the majority of these bodies 
 places them practically beyond the reach of our meridian 
 instrument, and the difficulty of observation is in many cases 
 further increased by the large errors of the predicted places. 
 After a fine autumn, the weather in the past winter and 
 spring has been remarkably bad. More than an entire 
 lunation was lost with the Transit Circle, no observation of 
 the Moon on the meridian having been possible between 
 January 8 and March I, a period of more than seven weeks. 
 Neither Sun nor stars were visible for eleven days, during 
 which period the clock-times were carried on entirely by the 
 preceding rate of the clock. The accumulated error at the 
 end of this time did not exceed o s> 3. Some difficulty was at 
 first experienced with the Thomson Electrometer, which was 
 traced to want of insulation. This has been mastered by the 
 use of glass supporters, which carry some sulphuric acid. 
 The instrument is now in excellent order, and the photo- 
 graphic registers have been perfectly satisfactory since 1879, 
 
AT GREENWICH OBSERVATORY 1876 TO 1 88 1. 325 
 
 February, when the new insulators were applied. From the 
 annual curves of diurnal inequality, deduced from the Mag- 
 netic Reductions, most important inferences may be drawn, 
 as to the connection between magnetic phenomena and sun- 
 spots. These annual curves shew a well-marked change in 
 close correspondence with the number of sun-spots. About 
 the epoch of maximum of sun-spots they are large and nearly 
 circular, having the same character as the curves for the 
 summer months ; whilst about the time of sun-spot minimum 
 they are small and lemniscate-shaped, with a striking resem- 
 blance to the curves for the winter months. The connection 
 between changes of terrestrial magnetism and sun-spots is 
 shewn in a still more striking manner by a comparison which 
 Mr Ellis has made between the monthly means of the diurnal 
 range of declination and horizontal force, and Dr R. Wolf's 
 'relative numbers' for frequency of sun-spots. The records 
 of sunshine with Campbell's Registering Sun-dial are pre- 
 served in a form easily accessible for reference, and the results 
 are communicated weekly to the Agricultural Gazette. Prof. 
 Oppolzer's results for the determination of the longitudes of 
 Vienna and Berlin, made in 1877, have now been made 
 public. They shew a remarkable agreement of the Chrono- 
 metric determination formerly made with the Telegraphic. 
 It may be of interest to recall the fact that a similar agree- 
 ment was found between the Chronometric and Telegraphic 
 determinations of the longitude of Valentia. For observing 
 the Transit of Venus of 1882, the general impression appears 
 to be that it will be best to confine our observations to simple 
 telescopic observations or micrometer observations at Ingress 
 and Egress, if possible at places whose longitudes are known. 
 For the first phenomenon (accelerated ingress) the choice of 
 stations is not good ; but for the other phenomena (retarded 
 ingress, accelerated egress, retarded egress) there appears to 
 be no difficulty. With regard to the Numerical Lunar 
 Theory : Respecting the discordance of Annual Equation, 
 I suspend my judgment I have now discussed the theory 
 
326 GEORGE BIDDELL AIRY. 
 
 completely ; and in going into details of secular changes, I 
 am at this time engaged on that which is the foundation of 
 all, namely, the change of excentricity of the Solar Orbit, 
 and its result in producing Lurfar Acceleration. An import- 
 ant error in the theoretical formulae for Variations of Radius 
 Vector, Longitude, and Latitude, was discovered ; some cal- 
 culations depending on them are cancelled." Referring to the 
 magnitude of the printed volume of "Greenwich Observa- 
 tions," and the practicability of reducing the extent of it, 
 the Report states thus : " The tendency of external scientific 
 movement is to give great attention to the phenomena of the 
 Solar disc (in which this Observatory ought undoubtedly to 
 bear its part). And I personally am most unwilling to recede 
 from the existing course of magnetical and meteorological 
 observations.... The general tendency of these considerations 
 is to increase the annual expenses of the Observatory. And 
 so it has been, almost continuously, for the last 42 years. 
 The annual ordinary expenses are now between 2\ and 3 
 times as great as in my first years at the Royal Observatory. 
 \/ Mr Gill was appointed to the Cape Observatory, and I 
 wrote out instructions for him in March : there was subse- 
 quently much correspondence respecting the equipment and 
 repairs of the Cape Observatory." In the Monthly Notices of 
 the Royal Astronomical Society for January an article had 
 appeared headed " Notes on the late Admiral Smyth's Cycle 
 of Celestial Objects, Vol. II." by Mr Herbert Sadler. In this 
 article Mr Sadler had criticized the work of Admiral Smyth 
 in a manner which Airy regarded as imputing bad faith to 
 Admiral Smyth. He at once took up the defence of his old 
 friend very warmly, and proposed certain Drafts of Resolu- 
 tions to the Council of the Society. These Resolutions were 
 moved, but were amended or negatived, and Airy immediately 
 resigned his office of Vice-President. There was considerable 
 negociation on the subject, and discussion with Lord Lindsay, 
 and on May Qth Airy's Resolutions were accepted by the 
 Council. In October Airy inspected the " Faraday " tele- 
 
AT GREENWICH OBSERVATORY 1 8/6 TO 1 88 1. 327 
 
 graph ship, then lying in the river near Messrs Siemens' 
 works, and broke his finger by a fall on board the vessel. In 
 this year Airy wrote and circulated a letter to the Members 
 of the Senate of the University of Cambridge, on the subject 
 of the Papers set in the Smith's Prizes Examination. In this 
 letter, as on former occasions, he objected much to the large 
 number of questions in " purely idle algebra, arbitrary combi- 
 nations of symbols, applicable to no further purpose." And 
 in particular he singled out for comment the following ques- 
 tion, which was one of those set, " Using the term circle as 
 extending to the case where the radius is a pure imaginary, 
 it is required to construct the common chord of two given 
 circles." This drew forth as usual a rejoinder from Prof. 
 Cayley, who wrote enclosing a solution of his problem, but 
 not at all to Airy's satisfaction, who replied as follows : " I am 
 not so deeply plunged in the mists of impossibles as to appre- 
 ciate fully your explanation in this instance, or to think that 
 it is a good criterion for University candidates." 
 
 Of private history: On Jan. 2ist he returned from Play- 
 ford. On March 22nd he attended the funeral of his sister at 
 Little Welnetham near Bury St Edmunds : Miss Elizabeth 
 Airy had lived with him at the Observatory from shortly 
 after his appointment. For about a week at the end of April 
 he was visiting Matlock, Edensor, and Buxton. From June 
 1 4th to July 1 8th he was staying at Portinscale near 
 Keswick. He was at Playford for two or three days in 
 October, and went there again on Dec. 23rd for his usual 
 winter holiday. 
 
 The following letter, relating to the life of Thomas Clark- 
 son, was written to Dr Merivale, Dean of Ely, after reading 
 the account in the " Times" of October loth of the unveiling 
 of a statue of Clarkson near Ware : 
 
328 GEORGE BIDDELL AIRY. 
 
 ROYAL OBSERVATORY, GREENWICH, 
 
 LONDON, S.E. 
 4*.^ 1879, October 11. 
 
 DEAR SIR, 
 
 Pardon my intrusion on you, in reference to a transaction 
 which has greatly interested me the honour paid by you to the 
 memory of Thomas Clarkson. With very great pleasure I have heard 
 of this step : and I have also been much satisfied with the remarks 
 on it in the "Times." I well remember, in Clarkson's "History of 
 the Abolition," which I read some 60 years ago, the account of the 
 circumstance, now commemorated by you, which determined the 
 action of his whole subsequent life. 
 
 It is not improbable that, among those who still remember 
 Clarkson, my acquaintance with him began at the earliest time of 
 all. I knew him, intimately, from the beginning of 1815 to his 
 death. The family which he represented must have occupied a very 
 good position in society. I have heard that he sold two good 
 estates to defray the expenses which he incurred in his personal 
 labours for Abolition : and his brother was Governor of Sierra Leone 
 (I know not at what time appointed). Thomas Clarkson was at St 
 John's College; and, as I gather from circumstances which I have 
 heard him mention, must have been a rather gay man. He kept a 
 horse, and at one time kept two. He took Orders in the Church ; 
 and on one occasion, in the course of his Abolition struggle, he 
 preached in a church. But he afterwards resolutely laid aside all 
 pretensions to the title of Minister of the Church, and never would 
 accept any title except as layman. He was, however, a very earnest 
 reader of theology during my acquaintance with him, and appeared 
 to be well acquainted with the Early Fathers. 
 
 The precise words in which was announced the subject for Prize 
 Essay in the University were "Anne liceat invitos in servitutem 
 trahere." 
 
 After the first great victory on the slave trade question, he estab- 
 lished himself in a house on the bank of Ullswater. I have not 
 identified the place : from a view which he once shewed me I sup- 
 posed it to be near the bottom of the lake : but from an account of 
 the storm of wind which he encountered when walking with a lady 
 over a pass, it seemed to be in or near Patterdale. When the 
 remains of a mountaineer, who perished in Helvellyn (as described 
 
AT GREENWICH OBSERVATORY 1876 TO 1 88 1. 329 
 
 in Scott's well-known poem), were discovered by a shepherd, it was 
 to Mr Clarkson that the intelligence was first brought. 
 
 He then lived at Bury St Edmunds. Mrs Clarkson was a lady 
 of Bury. But I cannot assign conjecturally any dates to his removals 
 or his marriage. His only son took his B.A. degree, I think, about 
 1817. 
 
 I think it was in 1814 that he began his occupation of Play ford 
 Hall a moated mansion near Ipswich, formerly of great import- 
 ance where he lived as Gentleman Farmer, managing a farm leased 
 from the Marquis of Bristol, and occupying a good position among 
 the gentry of the county. A relative of mine, with whom I was 
 most intimately acquainted, lived in the same parish (where in 
 defiance of school rules I spent nearly half my time, to my great 
 advantage as I believe, and where I still retain a cottage for occa- 
 sional residence), and I enjoyed much of Mr Clarkson's notice. It 
 was by his strong advice that I was sent to Cambridge, and that 
 Trinity College was selected: he rode with me to Rev. Mr Rogers 
 of Sproughton for introductory examination ; he introduced me to 
 Rev. C. Musgrave (subsequently of Halifax), accidentally doing duty 
 at Grundisburgh, who then introduced me to Sedgwick, Peacock, 
 and T. Musgrave (subsequently of York). In 1825, when I spent the 
 summer at Keswick, he introduced me to Southey and Wordsworth. 
 
 Mr Clarkson lived about thirty years at Playford Hall, and died 
 there, and lies interred with his wife, son, and grandson, in Playford 
 churchyard. I joined several friends in erecting a granite obelisk to 
 his memory in the same churchyard. His family is extinct : but a 
 daughter of his brother is living, first married to T. Clarkson's son, 
 and now Mrs Dickinson, of the Rectory, Wolferton. 
 
 I am, my dear Sir, 
 
 Very faithfully yours, 
 
 G. B. AIRY. 
 
 The Very Reverend, 
 
 The Dean of Ely. 
 
 1880 
 
 " The Admiralty, on final consideration of the estimates, 
 decided not to proceed with the erection of a new Library 
 
33 GEORGE BIDDELL AIRY. 
 
 near the Magnetic Observatory in the present year. In the 
 mean time the space has been cleared for the erection of a 
 building 50 by 20 feet. I have removed the Electrometer 
 Mast (a source of some 'expense* and some danger), the per- 
 fect success of Sir William Thomson's Electrometer rendering 
 all further apparatus for the same purpose unnecessary. 
 Many years ago a double-image micrometer, in which the 
 images were formed by the double refraction of a sphere of 
 quartz, was prepared by Mr Dollond for Capt. Smyth, R.N. 
 Adopting the same principle on a larger scale, I have had 
 constructed by Mr Hilger a micrometer with double refrac- 
 tion of a sphere of Iceland spar. Marks have been prepared 
 for examination of the scale, but I have not yet had oppor- 
 tunity of trying it. The spectroscopic determination of Star- 
 motions has been steadily pursued. The stars are taken 
 from a working list of 150 stars, which may eventually be 
 extended to include all stars down to the fourth magnitude, 
 and it is expected that in the course of time the motions of 
 about 300 stars may be spectroscopically determined. A 
 new pressure-plate with springs has been applied by Mr 
 Browning to Osier's Anemometer, and it is proposed to make 
 such modification as will give a scale extending to 5olbs. 
 pressure on the square foot. Other parts of the instrument 
 have also been renewed. As regards the reduction of the 
 magnetical results since 1863 : In the study of the forms of 
 the individual curves ; their relations to the hour, the month, 
 the year ; their connection with solar or meteorological facts ; 
 the conjectural physico-mechanical causes by which they are 
 produced ; there is much to occupy the mind. I regret that, 
 though in contemplation of these curves I have remarked 
 some singular (but imperfect) laws, I have not been able to 
 pursue them. The mean temperature of the year 1879 was 
 46*1, being 3*3 below the average of the preceding 38 years. 
 The highest temperature was 80*6 on July 30, and the lowest 
 137 on Dec. 7. The mean temperature was below the 
 average in every month of the year ; the months of greatest 
 
AT GREENWICH OBSERVATORY 1876 TO 1 88 1. 331 
 
 deviation being January and December, respectively 6'8 and 
 7*6 below the average ; the months of April, May, July, and 
 November were each between 4 and 5 below the average. 
 The number of hours of bright sunshine, recorded with 
 Campbell's Sunshine Instrument, during 1879, was only 
 983. In the summer of 1879 Commander Green, U.S.N., 
 came over to this country for the purpose of determining 
 telegraphically the longitude of Lisbon, as part of a chain of 
 longitudes extending from South America to Greenwich. A 
 successful interchange of signals was made with Commander 
 Green between Greenwich and Porthcurno on four nights, 
 1879, June 25 to 29. The results communicated by Com- 
 mander Green shew that the longitude of Lisbon Observatory, 
 as adopted in the Nautical Almanac, requires the large 
 correction of + 8'54 8 . With regard to the coming Transit of 
 Venus in 1882 : From the facility with which the requirements 
 for geographical position are satisfied, and from the rapid and 
 accurate communication of time now given by electric tele- 
 graph, the observation of this Transit will be comparatively 
 easy and inexpensive. I have attached greater importance 
 
 than I did formerly to the elevation of the Sun I remark 
 
 that it is highly desirable that steps be taken now for deter- 
 mining by telegraph the longitude of some point of Australia. 
 I have stated as the general opinion that it will be useless 
 to repeat photographic observations. In April Mr Barlow 
 called, in reference to the Enquiry on the Tay Bridge Disaster. 
 (The Bridge had been blown down on Dec. 28th, 1879.) I 
 prepared a memorandum on the subject for the Tay Bridge 
 Commission, and gave evidence in a Committee Room of the 
 House of Lords on Apr. 29th." (Much of the Astronomer 
 Royal's evidence on this occasion had reference to the 
 opinions which he had expressed concerning the wind- 
 pressure which might be expected on the projected Forth 
 Bridge, in 1873.) In May Airy was consulted by the Post- 
 master-General in the matter of a dispute which had arisen 
 between the Post Office and the Telephone Companies, which 
 
332 GEORGE BIDDELL AIRY. 
 
 latter were alleged to have infringed the monopoly of the 
 Post Office in commercial telegraphs : Airy made a declara- 
 tion on the subject. In July Mr Bakhuyzen came to England 
 to determine the longitude of* Leyden, on which he was 
 engaged till Sept. 9th. and carried on his observations at 
 the Observatory. In July Airy was much engaged in 
 perusing the records of Mr Gill's work at the Cape of Good 
 Hope. 
 
 Of private history : On Jan. 24th he returned from Play- 
 ford. From June I4th to July 4th he was again at Playford. 
 From September 2ist to October 2oth he was staying at 
 Portinscale near Keswick. On Dec. 23rd he went again to 
 Playford for his winter holiday. 
 
 Respecting the agitation at Cambridge for granting 
 University degrees to women, the following extract from a 
 letter addressed to a young lady who had forwarded a 
 Memorial on the subject for his consideration, and dated 
 Nov. loth, 1880, contains Airy's views on this matter. 
 
 " I have not signed the Memorial which you sent for my con- 
 sideration: and I will endeavour to tell you why. I entirely approve 
 of education of young women to a higher pitch than they do com- 
 monly reach. I think that they can successfully advance so far as 
 to be able clearly to understand with gratification to themselves 
 and with advantage to those whose education they will superintend 
 much of the results of the highest class of science which have been 
 obtained by men whose lives are in great measure devoted to it. 
 But I do not think that their nature or their employments will 
 permit of their mastering the severe steps of beginning (and indeed 
 all through) and the complicated steps at the end. And I think it 
 well that this their success should be well known as it is sure to be 
 among their relatives, their friends, their visitors, and all in whom 
 they are likely to take interest. Their connection with such a place 
 as Girton College is I think sufficient to lead to this. But I desire 
 above all that all this be done in entire subservience to what I 
 regard as infinitely more valuable than any amount of knowledge, 
 namely the delicacy of woman's character. And here, I think, our 
 views totally separate. I do not imagine that the University Degree 
 would really imply, as regards education, anything more than is 
 
AT GREENWICH OBSERVATORY 1876 TO 1 88 1. 333 
 
 known to all persons (socially concerned in the happiness of the 
 young woman) from the less public testimonial of the able men who 
 have the means of knowing their merits. And thus it appears to me 
 that the admission to University Degree would simply mean a more 
 extended publication of their names. I dread this." 
 
 1881 
 
 " The new line of underground telegraph wires has been 
 completed by the officers of the General Post Office. The 
 new route is down Groom's Hill in Greenwich, and the result 
 of this change, at least as regards the earth-current wires, and 
 probably as regards the other wires, has not been satisfactory. 
 It was soon found that the indications of the earth-current 
 wires were disturbed by a continual series of petty fluctua- 
 tions which almost completely masked the proper features of 
 
 earth currents If this fault cannot be removed, I should 
 
 propose to return to our original system of independent wires 
 (formerly to Croydon and Dartford). The new Azimuth- 
 mark (for the Altazimuth), upon the parapet of the Naval 
 College, is found to be perfectly satisfactory as regards both 
 steadiness and visibility. The observations of a low star for 
 zero of azimuth have been omitted since the beginning of 
 1 88 1 ; the mark, in combination with a high star, appearing 
 to give all that is necessary for this purpose. All the instru- 
 ments have suffered from the congealing of the oil during the 
 severe weather of the past winter, and very thorough cleaning 
 of all the moving parts has been necessary. The Solar 
 Eclipse of 1880, Dec. 31, was well observed. The first contact 
 was observed by four observers and the last contact by two. 
 The computations for the observations have been excep- 
 tionally heavy, from the circumstance that the Sun was very 
 low (86 1 4' Z. D. at the last observation) and that it has 
 therefore been necessary to compute the refraction with great 
 accuracy, involving the calculation of the zenith distance for 
 
334 GEORGE BIDUELL AIRY. 
 
 every observation. And besides this, eighty-six separate 
 computations of the tabular R. A. and N. P. D. of cusps have 
 been required. Amongst other interesting spectroscopic 
 observations of the Sun, a remarkable spectrum of a sun-spot 
 shewing 17 strong black lines or bands, each as broad as b^ 
 in the solar spectrum, was observed on 1880, Nov. 27 and 29. 
 These bands to which there is nothing corresponding in the 
 Solar Spectrum (except some very faint lines) have also been 
 subsequently remarked in the spectrum of several spots. 
 The Police Ship ' Royalist ' (which was injured by a collision 
 in 1879 an d had been laid up in dock) has not been again 
 moored in the river, and the series of observations of the 
 temperature of the Thames is thus terminated. Part of the 
 month of January 1881 was, as regards cold, especially severe. 
 The mean temperature of the period January 12 to 26 (15 
 days) was only 24'2, or 147 below the average ; the 
 temperature fell below 20 on 10 days, and rose above the 
 freezing point only on 3 days. The highest temperature in 
 this period was 35'3, the lowest 127. On January I7th 
 (while staying at Playford) my son Hubert and I noticed an 
 almost imperceptible movement in the upper clouds from the 
 South- East. On that night began the terrible easterly gale, 
 accompanied with much snow, which lasted to the night of 
 the 1 8th. The limiting pressure of 50 Ibs. on the square 
 foot of Osier's Anemometer was twice exceeded during this 
 storm. With respect to the Diurnal Inequalities of Magnetic 
 Horizontal Force : Assuming it to be certain that they 
 originate from the Sun's power, not immediately, but 
 mediately through his action on the Earth, it appears to 
 me (as I suggested long ago) that they are the effects of 
 the attraction of the red end or north end of the needle by the 
 heated portions of our globe, especially by the heated sea, 
 whose effect appears to predominate greatly over that of 
 the land. I do not say that everything is thus made perfectly 
 clear, but I think that the leading phenomena may be thus 
 explained. And this is almost necessarily the way of 
 
AT GREENWICH OBSERVATORY 1 8/6 TO 1 88 1. 335 
 
 beginning a science. In the first few years after the strict 
 and systematic examination of competitive chronometers, 
 beginning with 1856, the accuracy of chronometers was 
 greatly increased. For many years past it has been nearly 
 stationary. I interpret this as shewing that the effects of bad 
 workmanship are almost eliminated, and that future improve- 
 ment must be sought in change of some points of construction. 
 Referring to the Transit of Venus in 1874, the printing of all 
 sections of the Observations, with specimens of the printed 
 forms employed, and remarks on the photographic operations, 
 is very nearly completed. An Introduction is begun in 
 manuscript. I am in correspondence with the Commission 
 which is entrusted with the arrangements for observation of 
 the Transit of 1882. The Numerical Lunar Theory has been 
 much interrupted by the pressure of the Transit of Venus 
 work and other business." In his Report to the Board of 
 Visitors (his 46th and last), Airy remarks that it would be a 
 fitting opportunity for the expression of his views on the 
 general objects of the Observatory, and on the duties which 
 they impose on all who are actively concerned in its conduct. 
 And this he proceeds to do in very considerable detail. On 
 May 5th he wrote to Lord Northbrook (First Lord of the 
 Admiralty) and to Mr Gladstone to resign his post of 
 Astronomer Royal. From time to time he was engaged on 
 the subject of a house for his future residence, and finally 
 took a lease of the White House at the top of Groom's Hill, 
 just outside one of the gates of Greenwich Park. On the 
 1 5th of August he formally resigned his office to Mr W. H. M. 
 Christie, who had been appointed to succeed him as Astrono- 
 mer Royal, and removed to the White House on the next day, 
 August 1 6th. 
 
 His holiday movements in the portion of the year up to 
 August 1 6th consisted in his winter visit to Playford, from 
 which he returned on Jan. 24th : and a subsequent visit to 
 Playford from June 7th to i8th. 
 
336 GEORGE BIDDELL AIRY. 
 
 The following correspondence relating to Airy's retirement 
 from office testifies in a remarkable manner to the estimation 
 in which his services were held, and to the good feeling which 
 subsisted between him and his Official superiors. 
 
 10, DOWNING STREET, WHITEHALL, 
 June 6, iS8i. 
 
 DEAR SIR GEORGE AIRY, 
 
 I cannot receive the announcement of your resig- 
 nation, which you have just conveyed to me, without expressing my 
 strong sense of the distinction you have conferred upon the office of 
 Astronomer Royal, and of the difficulty of supplying your place with 
 a person of equal eminence. Let me add the expression of my best 
 wishes for the full enjoyment of your retirement from responsibility. 
 
 I remain, dear Sir George Airy, 
 Faithfully yours, 
 
 W. E. GLADSTONE. 
 
 ADMIRALTY, 
 June loth, 1881. 
 SIR, 
 
 I am commanded by my Lords Commissioners of the Admi- 
 ralty to acknowledge the receipt of your letter of the 4th instant, 
 intimating your desire to retire on the i5th August next from the 
 office of Astronomer Royal. 
 
 2. In reply I am to acquaint you that your wishes in this 
 matter have been communicated to the Prime Minister, and that the 
 further necessary official intimation will in due course be made to 
 the Treasury. 
 
 3. At the same time I am instructed by their Lordships to 
 convey to you the expression of their high appreciation of the 
 remarkably able and gifted manner, combined with unwearied 
 diligence and devotion to the Public Service (especially as regards 
 the Department of the State over which they preside), in which you 
 have performed the duties of Astronomer Royal throughout the long 
 period of forty-five years. 
 
 4. I am further to add that their Lordships cannot allow the 
 present opportunity to pass without giving expression to their sense 
 
AT GREENWICH OBSERVATORY 1876 TO l88l. 337 
 
 of the loss which the Public Service must sustain by your retirement, 
 and to the hope that you may long enjoy the rest to which you are 
 so justly entitled. 
 
 I am, Sir, 
 
 Your obedient Servant, 
 
 ROBERT HALL. 
 Sir G. B. Airy, K.C.B. 
 
 &>c., &>c., 
 Royal Observatory, Greenwich. 
 
 ADMIRALTY, 
 28/7* June, 1 88 1. 
 SIR, 
 
 My Lords Commissioners of the Admiralty have much 
 pleasure in transmitting copy of a resolution passed by the Board of 
 Visitors of the Royal Observatory on the 4th June last, bearing 
 testimony to the valuable services you have rendered to Astronomy, 
 to Navigation, and the allied Sciences throughout the long period 
 during which you have presided over the Royal Observatory. 
 
 I am, Sir, 
 
 Your obedient Servant, 
 
 ROBERT HALL. 
 Sir George Biddell Airy, K.C.B. 
 
 6<r., &c. y &c., 
 Royal Observatory, Greenwich. 
 
 " The Astronomer Royal (Sir George B. Airy) having an- 
 nounced his intention of shortly retiring from his position at 
 the Royal Observatory, the following resolution proposed by 
 Professor J. C. Adams, and seconded by Professor G. G. 
 Stokes, was then unanimously adopted and ordered to be 
 recorded in the Minutes of the Proceedings. 
 
 "The Board having heard from the Astronomer Royal 
 that he proposes to terminate his connection with the Ob- 
 servatory on the 1 5th of August next, desire to record in the 
 most emphatic manner their sense of the eminent services 
 
 A. B. 22 
 
338 GEORGE BIDDELL AIRY. 
 
 which he has rendered to Astronomy, to Navigation and the 
 allied Sciences, throughout the long period of 45 years during 
 which he has presided over the Royal Observatory. 
 
 "They consider that during that time he has not only 
 maintained but has greatly extended the ancient reputation 
 of the Institution, and they believe that the Astronomical and 
 other work which has been carried on in it under his direction 
 will form an enduring monument of his Scientific insight and 
 his powers of organization. 
 
 " Among his many services to Science, the following are a 
 few which they desire especially to commemorate : 
 
 (a) " The complete re-organization of the Equipment of 
 the Observatory. 
 
 (b) "The designing of instruments of exceptional sta- 
 bility and delicacy suitable for the increased accuracy of ob- 
 servation demanded by the advance of Astronomy. 
 
 (c) " The extension of the means of making observations 
 of the Moon in such portions of her orbit as are not accessible 
 to the Transit Circle. 
 
 (d) " The investigation of the effect of the iron of ships 
 upon compasses and the correction of the errors thence 
 arising. 
 
 (e) "The Establishment at the Observatory and else- 
 where of a System of Time Signals since extensively de- 
 veloped by the Government. 
 
 " The Board feel it their duty to add that Sir George Airy 
 has at all times devoted himself in the most unsparing 
 manner to the business of the Observatory, and has watched 
 over its interests with an assiduity inspired by the strongest 
 personal attachment to the Institution. He has availed him- 
 self zealously of every scientific discovery and invention which 
 was in his judgment capable of adaptation to the work of the 
 Observatory ; and the long series of his annual reports to the 
 Board of Visitors furnish abundant evidence, if such were 
 needed, of the soundness of his judgment in the appreciation 
 of suggested changes,, and of his readiness to introduce im- 
 
AT GREENWICH OBSERVATORY 1 876 TO 1 88 1. 339 
 
 provements when the proper time arrived. While maintain- 
 ing the most remarkable punctuality in the reduction and 
 publication of the observations made under his own superin- 
 tendance, he had reduced, collected, and thus rendered avail- 
 able for use by astronomers, the Lunar and Planetary Obser- 
 vations of his predecessors. Nor can it be forgotten that, 
 notwithstanding his absorbing occupations, his advice and 
 assistance have always been at the disposal of Astronomers 
 for any work of importance. 
 
 " To refer in detail to his labours in departments of 
 Science not directly connected with the Royal Observatory 
 may seem to lie beyond the province of the Board. But it 
 cannot be improper to state that its members are not un- 
 acquainted with the high estimation in which his contribu- 
 tions to the Theory of Tides, to the undulatory theory of 
 Light, and to various abstract branches of Mathematics are 
 held by men of Science throughout the world. 
 
 " In conclusion the Board would express their earnest 
 hope, that in his retirement Sir George Airy may enjoy 
 health and strength and that leisure for which he has often 
 expressed a desire to enable him not only to complete the 
 numerical Lunar Theory on which he has been engaged for 
 some years past, but also to advance Astronomical Science 
 in other directions." 
 
 ADMIRALTY, 
 2-jth October, 1881. 
 SIR, 
 
 I am commanded by my Lords. Commissioners of the Ad- 
 miralty to transmit to you, herewith, a copy of a Treasury Minute, 
 awarding you a Special Pension of ^uoo a year, in consideration 
 of your long and brilliant services as Astronomer Royal. 
 
 I am, Sir, 
 
 Your obedient Servant, 
 
 ROBERT HALL. 
 
 Sir G. B. Airy, K.C.B., RR.S., 6-v., &f. 
 The White House^ Groom's Hill, Greenwich, 
 
 22 2 
 
340 GEORGE BIDDELL AIRY. 
 
 Copy of Treasury Minute, dated loth October, 1881 : 
 
 My Lords have before them a statement of the services of Sir 
 George Biddell Airy, K.-C.B., F.R.S., who has resigned the appoint- 
 ment of Astronomer Royal on th ground of age. 
 
 Sir George Airy has held his office since the year 1835, and 
 has also, during that period, undertaken various laborious works, 
 demanding scientific qualifications of the highest order, and not 
 always such as could strictly be said to be included among the duties 
 of his office. 
 
 The salary of Sir G. Airy as Astronomer Royal is .1200 a year, 
 in addition to which he enjoys an official residence rent free, and, 
 under ordinary circumstances he would be entitled to a pension 
 equal to two-thirds of his salary and emoluments. 
 
 My Lords, however, in order to mark their strong sense of the 
 distinction which, during a long and brilliant career Sir George Airy 
 has conferred upon his office, and of the great services which, in 
 connection with, as well as in the discharge of, his duties, he has 
 rendered to the Crown and the Public, decide to deal with his case 
 under the ixth Section of the Superannuation Act, 1859, which 
 empowers them to grant a special pension for special services. 
 
 Accordingly my Lords are pleased to award to Sir George 
 Biddell Airy, K.C.B., F.R.S., a special Retired Allowance of 
 per annum. 
 
 THE WHITE HOUSE, 
 GROOM'S HILL, GREENWICH, 
 
 1 88 1, October 29. 
 SIR, 
 
 I have the honour to acknowledge your letter of October 27, 
 transmitting to me, by instruction of The Lords Commissioners of 
 Admiralty, copy of a Treasury Minute dated 1881 October 10, in 
 which the Lords Commissioners of Her Majesty's Treasury are 
 pleased to award to me an annual retired allowance of ^"iioo per 
 annum. 
 
 Acknowledging the very liberal award of the Lords Commis- 
 sioners of Treasury, and the honourable and acceptable terms in 
 which it is announced, I take leave at the same time to offer to 
 
AT GREENWICH OBSERVATORY 1876 TO 1 88 1. 341 
 
 Their Lordships of the Admiralty my recognition of Their Lordships' 
 kindness and courtesy in thus handing to me copy of the Treasury 
 Minute. 
 
 I have the honour to be, Sir, 
 
 Your very obedient Servant, 
 
 G. B. AIRY. 
 The Secretary of the Admiralty. 
 
 From the Assistants of the Royal Observatory, with 
 whom he was in daily communication, whose faithful and 
 laborious services he had so often thankfully recognized in 
 his Annual Reports to the Board of Visitors, and to whom so 
 much of the credit and success of the Observatory was due, 
 he received the following address : 
 
 ROYAL OBSERVATORY, GREENWICH, 
 1 88 1, August ii. 
 
 DEAR SIR, 
 
 We cannot allow the official relation which has so long 
 existed between yourself and us to terminate without expressing to 
 you our sense of the admirable manner in whicfr you have, in our 
 opinion, upheld the dignity of the office of Astronomer Royal 
 during the many years that you have occupied that important post. 
 
 Your long continued and varied scientific work has received 
 such universal recognition from astronomers in all lands, that it is 
 unnecessary for us to do more than assure you how heartily we join 
 in their appreciation of your labours. We may however add that 
 our position has given us opportunities of seeing that which others 
 cannot equally well know, the untiring energy and great industry 
 which have been therein displayed throughout a long and laborious 
 career, an energy which leads you in retirement, and at fourscore 
 years of age, to contemplate further scientific work. 
 
 We would ask you to carry with you into private life the best 
 wishes of each one of us for your future happiness, and that of your 
 family, expressing the hope that the days of retirement may not be 
 
342 GEORGE BIDDELL AIRY. 
 
 few, and assuring you that your name will long live in our re- 
 membrance. 
 
 We are, dear. Sir, 
 
 Yours very faithfully, 
 
 W. H. M. CHRISTIE, EDWIN DUNKIN, WILLIAM 
 ELLIS, GEORGE STRICKLAND CRISWICK, W. 
 C. NASH, A. M. W. DOWNING, EDWARD W. 
 MAUNDER, W. G. THACKERAY, THOMAS LEWIS. 
 
 Sir G. B. Airy, K.C.B., &c., &v., 
 Astronomer Royal. 
 
 ROYAL OBSERVATORY, GREENWICH, 
 1 88 1, August 13. 
 
 MY DEAR MR CHRISTIE, 
 
 and Gentlemen of the Royal Observatory, 
 
 With very great pleasure I have received 
 
 your letter of August n. I thank you much for your recognition 
 of the general success of the Observatory, and of a portion of its 
 conduct which as you remark can scarcely be known except to 
 those who are every day engaged in it : but I thank you still more 
 for the kind tone of your letter, which seems to shew that the terms 
 on which we have met are such as leaves, after so many years' 
 intercourse, no shadow of complaint on any side. 
 
 Reciprocating your wishes for a happy life, and in your case a 
 progressive and successful one, 
 
 I am, 
 
 My dear Mr Christie and Gentlemen, 
 Yours faithfully, 
 
 G. B. AIRY. 
 
 Throughout his tenure of office Airy had cultivated and 
 maintained the most friendly relations with foreign astrono- 
 mers, to the great advantage of the Observatory. Probably 
 
AT GREENWICH OBSERVATORY 1876 TO 1 88 1. 343 
 
 all of them, at one time or another, had visited Greenwich, 
 and to most of them he was well known. On his retirement 
 from office he received an illuminated Address from his 
 old friend Otto Struve and the staff of the Pulkowa Observa- 
 tory, an illuminated Address from the Vorstand of the 
 Astronomische Gesellschaft at Berlin signed by Dr Auwers 
 and the Secretaries, a complimentary letter from the 
 Academy of Sciences at Amsterdam, and friendly letters of 
 sympathy from Dr Gould, Prof. Newcombe, Dr Listing, and 
 from many other scientific friends and societies. His replies 
 to the Russian and German Addresses were as follows : 
 
 ROYAL OBSERVATORY, GREENWICH, 
 1 88 1, Augtist 5. 
 
 MY DEAR SIR, 
 
 I received, with feelings which I will not attempt 
 to describe, the Address of yourself and the Astronomers of Pul- 
 kowa generally, on the occasion of my retirement from the office 
 of Astronomer Royal. I can scarcely credit myself with possessing 
 all the varied claims to your scientific regard which you detail. I 
 must be permitted to attribute many of them to the long and 
 warm friendship which has subsisted so long between the Directors 
 of the Pulkowa Observatory and myself, and which has influenced 
 the feelings of the whole body of Astronomers attached to that 
 Institution. On one point, however, I willingly accept your favour- 
 able expressions I have not been sparing of my personal labour 
 and to this I must attribute partial success on some of the subjects 
 to which you allude. 
 
 In glancing over the marginal list of scientific pursuits, I remark 
 with pleasure the reference to Optics. I still recur with delight to 
 the Undulatory Theory, once the branch of science on which I was 
 best known to the world, and which by calculations, writings, and 
 lectures, I supported against the Laplacian School. But the close 
 of your remarks touches me much more the association of the 
 name of W. Struve and my own. I respected deeply the whole 
 character of your Father, and I believe that he had confidence in 
 me. From our first meeting in 1830 (on a Commission for im- 
 provement of the Nautical Almanac) I never ceased to regard him 
 as superior to others. I may be permitted to add that the delivery 
 
344 GEORGE BIDDELL AIRY. 
 
 of his authority to the hands of his son has not weakened the con- 
 nection of myself with the Observatory of Poulkova. 
 
 Acknowledging gratefully your kindness, and that of all the 
 Astronomers of the Observatory?'*of Poulkova, and requesting you 
 to convey to them this expression, 
 
 I am, my dear ^ir, 
 
 Yours most truly, 
 
 G. B. AIRY. 
 
 To M. Otto von Struve, 
 
 Director of the Observatory of Poulkova 
 and the Astronomers of that Observatory. 
 
 ROYAL OBSERVATORY, GREENWICH, 
 1 88 1, August 3. 
 
 MY DEAR SIR, 
 
 With very great pleasure I received the Address of 
 the Astronomische Gesellschaft on occasion of my intended resigna- 
 tion of the Office of Astronomer Royal: dated July 27, and signed 
 by yourself as President and Messrs Schoenfeld and Winnecke as 
 Secretaries of the Astronomische Gesellschaft. I thank you much 
 for the delicacy of your arrangement for the transmission of this 
 document by the hands of our friend Dr Huggins. And I think 
 you will be gratified to learn that it arrived at a moment when I 
 was surrounded by my whole family assembled at my jour-de-fete, 
 and that it added greatly to the happiness of the party. 
 
 I may perhaps permit myself to accept your kind recognition of 
 my devotion of time and thought to the interests of my Science and 
 my Office. It is full reward to me that they are so recognized. 
 As to the success or utility of these efforts, without presuming, 
 myself, to form an opinion, I acknowledge that the connection 
 made by the Astronomische Gesellschaft, between my name and 
 the advance of modern astronomy, is most flattering, and will always 
 be remembered by me with pride. 
 
 It is true, as is suggested in vour Address, that one motive for 
 my resignation of Office was the desire to find myself more free 
 
AT GREENWICH OBSERVATORY 1876 TO 1 88 1. 345 
 
 for the prosecution of further astronomical investigations. Should 
 my health remain unbroken, I hope to enter shortly upon this 
 undertaking. 
 
 Again acknowledging the kindness of yourself and the Vorstand 
 of the Astronomische Gesellschaft, and offering my best wishes for 
 the continued success of that honourable institution, 
 
 I am, my dear Sir, 
 
 Yours very truly, 
 
 G. B. AIRY. 
 To Dr Auwers 
 
 and the Vorstand of the 
 Astronomische Gesellschaft. 
 
CHAPTER X. 
 
 AT THE WHITE HOUSE, GREENWICH. FROM HIS RESIG- 
 NATION OF OFFICE ON AUGUST ISTH, 1881, TO HIS 
 DEATH ON JANUARY 2ND, 1892. 
 
 HISTORY OF HIS LIFE AFTER HIS RESIGNATION OF 
 
 OFFICE. 
 
 ON the i6th of August 1881 Airy left the Observatory 
 which had been his residence for nearly 46 years, and re- 
 moved to the White House. Whatever his feelings may have 
 been at the severing of his old associations he carefully kept 
 them to himself, and entered upon his new life with the 
 cheerful composure and steadiness of temper which he pos- 
 sessed in a remarkable degree. He was now more than 
 80 years old, and the cares of office had begun to weigh 
 heavily upon him : the long-continued drag of the Transit 
 of Venus work had wearied him, and he was anxious to 
 carry on and if possible complete his Numerical Lunar 
 Theory, the great work which for some years had occu- 
 pied much of his time and attention. His mental powers 
 were still vigorous, and his energy but little impaired : his 
 strong constitution, his regular habits of life, the systematic 
 relief which he obtained by short holiday expeditions when- 
 ever he found himself worn with work, and his keen interest 
 in history, poetry, classics, antiquities, engineering, and other 
 subjects not immediately connected with his profession, had 
 combined to produce this result. And in leaving office, he 
 had no idea of leaving off work ; his resignation of office 
 merely meant for him a change of work. It is needless to 
 
AT THE WHITE HOUSE, GREENWICH. 347 
 
 say that his interest in the welfare and progress of the 
 Observatory was as keen as ever ; his advice was always 
 at the service of his successor, and his appointment as 
 Visitor a year or two after his resignation gave him an 
 official position with regard to the Observatory which he 
 much valued. The White House, which was to be his 
 home for the rest of his life, is just outside one of the 
 upper gates of the Park, and about a quarter of a mile 
 from the Observatory. Here he resided with his two un- 
 married daughters. The house suited him well and he was 
 very comfortable there : he preferred to live in the neigh- 
 bourhood with which he was so familiar and in which he 
 was so well known, rather than to remove to a distance. 
 His daily habits of life were but little altered : he worked 
 steadily as formerly, took his daily walk on Blackheath, 
 made frequent visits to Playford, and occasional expedi- 
 tions to the Cumberland Lakes and elsewhere. 
 
 The work to which he chiefly devoted himself in his 
 retirement was the completion of his Numerical Lunar 
 Theory. This was a vast work, involving the subtlest con- 
 siderations of principle, very long and elaborate mathe- 
 matical investigations of a high order, and an enormous 
 amount of arithmetical computation. The issue of it was 
 unfortunate : he concluded that there was an error in some 
 of the early work, which vitiated the results obtained : and 
 although the whole process was published, and was left in 
 such a state that it would be a comparatively simple task 
 for a future astronomer to correct and complete it, yet it 
 was not permitted to the original author of it to do this. 
 To avoid the necessity of frequent reference to this work 
 in the history of Airy's remaining years, it will be con- 
 venient to summarize it here. It was commenced in 1872 : 
 "On Feb. 23rd in this year I first (privately) formed the 
 notion of preparing a Numerical Lunar Theory by substi- 
 tuting Delaunay's numbers in the proper Equations and 
 seeing what would come of it." From this time forward 
 
348 GEORGE BIDDELL AIRY. 
 
 till his power to continue it absolutely failed, he pursued 
 the subject with his usual tenacity of purpose. During his 
 tenure of office every available opportunity was seized for 
 making progress with his Lunar Theory, and in every Report 
 to the Visitors a careful statement was inserted of the state 
 in which it then stood. And, after his resignation of office, 
 it formed the bulk of his occupation. In 1873 the Theory 
 was formed, and by 1874 it was so far advanced that he 
 published in the Monthly Notices of the Royal Astronomical 
 Society a statement of the fundamental points of the Theory. 
 In 1875, the Theory having advanced to a stage where ex- 
 tensive arithmetical computation was required, he obtained 
 a small grant from the Government in aid of the expense 
 of the work, and other grants were made in subsequent 
 years. By 1878 the calculations were so far advanced that 
 an opinion could be formed as to the probable accuracy of 
 the Theory, and the following remark is made: "A cursory 
 collation of the terms relating to the Areas (in the Ecliptic) 
 led me to suppose that there might be some error in the 
 computations of the Annual Equation and related terms;" 
 but no error could be discovered and the work proceeded. 
 The complex character of the Theory, and the extreme care 
 required in the mathematical processes, are well illustrated 
 by the following statement, which occurs in the Report of 
 1879, "An important error in the theoretical formulae for 
 Variations of Radius Vector, Longitude, and Latitude, was 
 discovered ; some calculations depending on them are can- 
 celled." In 1880 and 1881 the work was continued, but was 
 " sadly interrupted by the pressure of the Transit of Venus 
 work and other business." After his resignation of the Office 
 of Astronomer Royal he had no further public assistance, 
 and did much of the computations himself, but a sum of 
 ,100 was contributed by Mr De La Rue in furtherance of 
 the work, and this sum was spent on computers. In his 
 retirement the work made good progress, and on Dec. 3ist, 
 1882, he made the following note: "I finished and put in 
 
AT THE WHITE HOUSE, GREENWICH. 349 
 
 general order the final tables of Equations of Variations. 
 
 This is a definite point in the Lunar Theory I hope 
 
 shortly to take up severely the numerical operations of the 
 Lunar Theory from the very beginning." The work was 
 continued steadily through 1883, and on Mar. 24th, 1884, he 
 made application through the Board of Visitors to the Ad- 
 miralty to print the work : after the usual enquiries as to 
 the expense this was acceded to, and copy was sent to the 
 printers as soon as it was ready. The first printed proofs 
 were received on Feb. 5th, 1885, and the whole book was 
 printed by the end of 1886. From the frequent references 
 in his journal to errors discovered and corrected during the 
 progress of these calculations, it would seem likely that his 
 powers were not what they had been, and that there was 
 a probability that some important errors might escape cor- 
 rection. He was far too honest to blind himself to this pos- 
 sibility, and in the Preface to his Numerical Lunar Theory 
 he says thus : " I have explained above that the principle 
 of operations was, to arrange the fundamental mechanical 
 equations in a form suited for the investigations of Lunar 
 Theory; to substitute in the terms of these equations the 
 numerical values furnished by Delaunay's great work ; and 
 to examine whether the equations are thereby satisfied. 
 With painful alarm, I find that they are not satisfied; and 
 that the discordance, or failure of satisfying the equations, 
 is large. The critical trial depends on the great mass of 
 computations in Section II. These have been made in du- 
 plicate, with all the care for accuracy that anxiety could 
 supply. Still I cannot but fear that the error which is the 
 source of discordance must be on my part. I cannot con- 
 jecture whether I may be able to examine sufficiently into 
 this matter." He resolutely took in hand the revision of his 
 work, and continued it till October 1888. But it is clear 
 from the entries in his journal that his powers were now 
 unequal to the task, and although from time to time he 
 suspected that he had discovered errors, yet it does not 
 
350 GEORGE BIDDELL AIRY. 
 
 appear that he determined anything with certainty. He 
 never doubted that there were important errors in the 
 work, and later on he left the following private note on 
 the subject : 
 
 NUMERICAL LUNAR THEORY. 
 
 '-1890, Sept. 29. 
 
 I had made considerable advance (under official difficulties) in 
 calculations on my favourite Numerical Lunar Theory, when I 
 discovered that, under the heavy pressure of unusual matters (two 
 Transits of Venus and some eclipses) I had committed a grievous 
 error in the first stage of giving numerical value to my Theory. 
 
 My spirit in the work was broken, and I have never heartily 
 proceeded with it since. 
 
 G. B. AIRY. 
 
 Probably the error referred to here is the suspected error 
 mentioned above in his Report of 1878, as to which he sub- 
 sequently became more certain. 
 
 Whatever may be the imperfections of the Numerical 
 Lunar Theory, it is a wonderful work to have been turned out 
 by a man 85 years old. In its idea and inception it embodies 
 the experience of a long life actively spent in practical science. 
 And it may be that it will yet fulfil the objects of its author, 
 and that some younger astronomer may take it up, correct its 
 errors (wherever they may be), and fit it for practical use. 
 And then the labour bestowed upon it will not have been 
 in vain. 
 
 Subject always to the absorbing occupations of the Lunar 
 Theory he amused himself with reading his favourite subjects 
 of History and Antiquities. His movements during the 
 remainder of the year 1881 were as follows: In September he 
 paid a two days' visit to Lady Herschel at Hawkhurst. From 
 Oct. 4th to i /th he was at the Cumberland Lakes and 
 engaged in expeditions in the neighbourhood. From Nov. 
 5th to 8th he was at Cambridge, inspecting Prof. Stuart's 
 workshops, and other scientific institutions. On Dec. I3th 
 
AT THE WHITE HOUSE, GREENWICH. 351 
 
 he went to Playford. Amongst miscellaneous matters : in 
 November he wrote to Mr Rothery on the loss of the 
 ' Teuton ' at some length, with suggestions for the safer 
 construction of such vessels. In October he was asked for 
 suggestions regarding the establishment of a " Standard 
 Time " applicable to the railway traffic in the United 
 States : he replied as follows : 
 
 1881, Oct. 31. 
 SIR, 
 
 I have to acknowledge your letter of October 17, introducing 
 to my notice the difficulty which appears to be arising in America 
 regarding a "Standard Time," for extensive use throughout N. 
 America "applicable to railway traffic only." The subject, as 
 including considerations of convenience in all the matters to which 
 it applies, is one of difficulties probably insuperable. The certainty, 
 however, that objections may be raised to every scheme, renders me 
 less timid in offering my own remarks ; which are much at your 
 service. 
 
 I first comment upon your expression of "Standard Time 
 
 applicable to railway traffic only." But do you mean this as affecting 
 the transactions between one railway and another railway, or as 
 affecting each railway and the local interests (temporal and others) of 
 the towns which it touches ? The difference is so great that I should 
 be disposed to adopt it as marking very strongly the difference to be 
 made between the practices of railways among themselves and the 
 practices of railways towards the public ; and will base a system on 
 that difference. 
 
 As regards the practices of railways among themselves : if the 
 various railways of America are joined and inosculated as they are in 
 England, it appears to me indispensable that they have one common 
 standard among themselves : say Washington Observatory time. But 
 this is only needed for the office-transactions between the railways ; 
 it may be kept perfectly private ; never communicated to the public 
 at all. And I should recommend this as the first step. 
 
 There will then be no difficulty in deducing, from these private 
 Washington times, the accurate local times at those stations (whose 
 longitude is supposed to be fairly well known, as a sailor with a 
 sextant can determine one in a few hours) which the railway authori- 
 ties may deem worthy of that honour; generally the termini of 
 
352 GEORGE BIDDELL AIRY. 
 
 railways. Thus we shall have a series of bases of local time, of 
 authoritative character, through the country. 
 
 Of such bases we have two, Greenwich and Dublin : and they 
 are separated by a sea-voyage. Ijg the U.S. of America there must 
 be a greater number, and probably not so well separated. Still it is 
 indispensable to adopt such a system of local centers. 
 
 No people in this world can be induced to use, a reckoning which 
 does not depend clearly upon the sun. In all civilized countries it 
 depends (approximately) on the sun's meridian passage. Even the 
 sailor on mid-ocean refers to that phenomenon. And the solar 
 passage, with reasonable allowance, 2om. or 3om. one way or 
 another, must be recognized in all time-arrangements as giving the 
 fundamental time. The only practical way of doing this is, to adopt 
 for a whole region the fundamental time of a center of that region. 
 
 And to this fundamental time, the local time of the railway, as 
 now entering into all the concerns of life, must be adapted. A 
 solicitor has an appointment to meet a client by railway ; a physician 
 to a consultation. How is this to be kept if the railway uses one 
 time and every other act of life another ? 
 
 There is one chain of circumstances which is almost peculiar 
 that of the line from New York to San Francisco. Here I would 
 have two clocks at every station : those on the north side all shewing 
 San Francisco time, and those on the south all shewing New York 
 time. Every traveller's watch would then be available to the end of 
 his journey. 
 
 A system, fundamentally such as I have sketched, would give 
 little trouble, and may I think be adopted with advantage. 
 
 I am, Sir, 
 
 Your faithful servant, 
 
 G. B. AIRY. 
 Mr Edward Barrington. 
 
 1882 
 
 He returned from Playford on Jan. 17 : his other move- 
 ments during the year were as follows : from Apr. 2/th to 
 May nth he was at Playford ; and again from August 1st to 
 24th. From Oct. 9th to Nov. 1st he was travelling with his 
 two unmarried daughters in the Lake District of Cumber- 
 
AT THE WHITE HOUSE, GREENWICH. 353 
 
 land : the journey was by Furness and Coniston to Portinscale 
 near Keswick ; on Oct. I3th he fell and sprained his ankle, 
 and his excursions for the rest of the time were mainly con- 
 ducted by driving. Shortly after his return, on Nov. nth, 
 while walking alone on Blackheath, he was seized with a 
 violent attack of illness, and lay helpless for some time before 
 he was found and brought home : he seems however to have 
 recovered to a great extent in the course of a day or two, and 
 continued his Lunar Theory and other work as before. On 
 June 22nd he made the following sad note, " This morning, 
 died after a most painful illness my much-loved daughter-in- 
 law, Anna Airy, daughter of Professor Listing of Gottingen, 
 wife of my eldest son Wilfrid." In February he wrote out 
 his reminiscences of the village of Playford during his boy- 
 hood. 
 
 In June he was much disturbed in mind on hearing of 
 some important alterations made by the Astronomer Royal 
 in the Collimators of the Transit Circle, and some correspon- 
 dence ensued on the subject. During the year he had much 
 correspondence on the subject of the subsidences on Black- 
 heath. 
 
 The following letter was written in reply to a gentleman 
 who had asked whether it could be ascertained by calculation 
 how long it is since the Glacial Period existed : 
 
 1882, July 4. 
 
 SIR, 
 
 I should have much pleasure in fully answering your questions 
 of July 3 if I were able to do so : but the subject really is very 
 obscure. 
 
 (T) Though it is recognized that the glacial period (or periods) 
 is late, I do not think that any one has ventured to fix upon a rude 
 number of years since elapsed. 
 
 (2) We have no reason to think that the mean distance of the 
 earth from the sun has sensibly altered. There have been changes 
 in the eccentricity of the orbit (making the earth's distance from the 
 sun less in one month and greater in the opposite month), but I do 
 not perceive that this would explain glaciers. 
 
 A. B. 23 
 
354 GEORGE BIDDELL AIRY. 
 
 (3) I consider it to be certain that the whole surface of the 
 earth, at a very distant period, was very hot, that it has cooled 
 gradually, and (theoretically and imperceptibly) is cooling still. The 
 glaciers must be later' than thes,0 hot times, and later than our last 
 .consolidated strata : but this is nearly all that I can say. 
 
 I am, Sir, Your obedient Servant, 
 
 *- G. B. AIRY. 
 James Alston, Esq. 
 
 1883 
 
 From May 2nd to 2Qth he was at Play ford. From July 
 loth to 2Oth he was travelling in South Wales with his 
 daughters. From Oct. loth to Nov. loth he was at Play ford. 
 Between Nov. 2Oth of this year and Jan. 4th of the year 
 1884, he sat several times to Mr John Collier for his portrait : 
 the picture was exhibited in the Academy of 1884; it is a 
 most successful and excellent likeness. 
 
 Throughout the year he was very busy with the Numerical 
 Lunar Theory. In March he was officially asked to accept 
 the office of Visitor of the Royal Observatory, which he 
 accepted, and in this capacity attended at the Annual 
 Visitation on June 2nd, and addressed a Memorandum to 
 the Visitors on the progress of his Lunar Theory. On 
 March I2th he published in several newspapers a state- 
 ment in opposition to the proposed Braithwaite and 
 Buttermere Railway, which he considered would be injurious 
 to the Lake District, in which he took so deep an interest. 
 In May he communicated to " The Observatory " a statement 
 of his objections to a Theory advanced by Mr Stone (then 
 President of the Royal Astronomical Society) to account for 
 the recognized inequality in the Mean Motion of the Moon. 
 This Theory, on a subject to which Airy had given his 
 incessant attention for so many years, would naturally receive 
 his careful attention and criticism, and it attracted much 
 general notice at the time. In December he wrote to the 
 
AT THE WHITE HOUSE, GREENWICH. 355 
 
 Secretary of the Royal Astronomical Society his opinion as 
 to the award of the Medal of the Society. In this letter he 
 stated the principles which guided him as follows : " I have 
 always maintained that the award of the Medal ought to be 
 guided mainly by the originality of communications : that one 
 advance in a new direction ought in our decision to outweigh 
 any mass of work in a routine already established : and that, 
 in any case, scientific utility as distinguished from mere 
 elegance is indispensable." In July Lieut. Pinheiro of the 
 Brazilian Navy called with an autograph letter of introduction 
 from the Emperor of Brazil. The Lieutenant desired to make 
 himself acquainted with the English system of Lighthouses 
 and Meteorology, and Airy took much trouble in providing 
 him with introductions through which he received every 
 facility for the thorough accomplishment of his object. On 
 Oct. 8th he forwarded to Prof. Cayley proofs of Euclid's 
 Propositions I. 47 and III. 35 with the following remarks: 
 " I place on the other side the propositions which may be 
 substituted (with knowledge of Euclid's VI. book) for the 
 two celebrated propositions of the geometrical books. They 
 leave on my mind no doubt whatever that they were invented 
 as proofs by ratios, and that they were then violently expanded 
 into cumbrous geometrical proofs." On June 28th he declined 
 to sign a memorial asking for the interment of Mr Spottis- 
 woode in Westminster Abbey, stating as his reason, " I take 
 it, that interment possessing such a public character is a 
 public recognition of benefits, political, literary, or philo- 
 sophical, whose effects will be great and durable. Now I 
 doubt whether it can be stated that Mr Spottiswoode had 
 conferred such benefits on Society." But he adds at length 
 his cordial recognition of Mr Spottiswoode's scientific services. 
 Throughout his life Airy was a regular attendant at church, 
 and took much interest in the conduct of the Church services. 
 In October of this year he wrote a long letter to the Vicar of 
 Greenwich on various points, in which occurs the following 
 paragraph : " But there is one matter in the present form of 
 
 23 2 
 
356 GEORGE BIDDELL AIRY. 
 
 the Church Service, on which my feeling is very strong, 
 namely the (so-called, I believe) Choral Service, in the 
 Confession, the Prayer, and the Creed. I have long listened 
 with veneration to our noble ^Liturgy, and I have always been 
 struck with the deep personally religious feeling which per- 
 vades it, especially those parts of it which are for ' The 
 People.' And an earnest Priest, earnestly pressing these 
 parts by his vocal example on the notice of the People, can 
 scarcely fail to excite a corresponding earnestness in them. 
 All this is totally lost in the choral system. For a venerable 
 persuasion there is substituted a rude irreverential confusion 
 of voices; for an earnest acceptance of the form offered by 
 the Priest there is substituted in my feeling at least a 
 weary waiting for the end of an unmeaning form." He also 
 objected much to singing the responses to the Command- 
 ments. 
 
 1884 
 
 From Apr. 2Qth to May 3Oth he was at Playford, con- 
 cluding his Journal there with the note " So ends a plea- 
 sant Vacation." On June nth he went to Cambridge and 
 attended the Trinity College Commemoration Service, and 
 dined in Hall. From Aug. I4th to Sept. nth he was at 
 Playford. On Sept. 26th he made an expedition to Guild- 
 ford and Farnham. During this year he was closely en- 
 gaged on the Numerical Lunar Theory, and for relaxation 
 was reading theology and sundry books of the Old Testa- 
 ment. 
 
 On June 7th he attended at the Visitation of the Royal 
 Observatory. In a letter written in April to Lt.-Col. Marin- 
 din, R.A., on the subject of wind pressure there occurs the 
 following remark : " When the heavy gusts come on, the 
 wind is blowing in directions changing rapidly, but limited 
 in extent. My conclusion is that in arches of small extent 
 (as in the Tay Bridge) every thing must be calculated for 
 
AT THE WHITE HOUSE, GREENWICH. 357 
 
 full pressure; but in arches of large extent (as in the Forth 
 Bridge) every thing may be calculated for small pressure. 
 And for a suspension bridge the pressure is far less dan- 
 gerous than for a stiff arch," In January he had some 
 correspondence with Professor Tyndall on the Theory of 
 the "White Rainbow," and stated that he thoroughly agreed 
 with Dr Young's explanation of this phenomenon. The 
 following is extracted from a letter on May 1st to his old 
 friend Otto Struve : " I received from you about 3 or 4 
 weeks past a sign of your friendly remembrance, a copy of 
 your paper on the Annual Parallax of Aldebaran. It pleased 
 me much. Especially I was delighted with your noble re- 
 tention of the one equation whose result differed so sensibly 
 from that of the other equations. It is quite possible, even 
 probable, that the mean result is improved by it. I have 
 known such instances. The first, which attracted much at- 
 tention, was Capt. Kater's attempt to establish a scale of 
 longitude in England by reciprocal observations of azimuth 
 between Beachy Head and Dunnose. The result was evi- 
 dently erroneous. But Colonel Colby, on examination of 
 the original papers, found that some observations had been 
 omitted, as suspicious ; and that when these were included the 
 mean agreed well with the scale of observation inferred from 
 other methods." In a letter to the Rev. R. C. M. Rouse, ac- 
 knowledging the receipt of a geometrical book, there occurs 
 the following paragraph: "I do not value Euclid's Elements 
 as a super-excellent book of instruction though some im- 
 portant points are better presented in it than in any other 
 book of geometrical instruction that I have seen. But I 
 value it as a book of strong and distinct reasoning, and of 
 orderly succession of reasonings. I do not think that there 
 is any book in the world which presents so distinctly the ( be- 
 cause therefore ' And this is invaluable for the mental 
 
 education of youth." In May he was in correspondence with 
 Professor Balfour Stewart regarding a projected movement 
 in Terrestrial Magnetism to be submitted to the British 
 
GEORGE BIDDELL AIRY. 
 
 Association. Airy cordially approved of this movement, 
 and supported it to the best of his ability, stating that in 
 his opinion what was mainly wanted was the collation of 
 existing records. In January and February he was much 
 pressed by Prof. Pritchard of Oxford to give his opinion as 
 to the incorrectness of statements made by Dr Kinns in his 
 Lectures on the Scientific Accuracy of "the Bible. Airy 
 refused absolutely to take part in the controversy, but he 
 could not escape from the correspondence which the matter 
 involved : and this led up to other points connected with 
 the early history of the Israelites, a subject in which he took 
 much interest. 
 
 1885 
 
 From May 4th to June 3rd he was at Playford. From 
 July 2nd to 22nd he was in the Lake District. The journey 
 was by Windermere to Kentmere, where he made enquiries 
 concerning the Airy family, as it had been concluded with 
 much probability from investigations made by his nephew, 
 the Rev. Basil R. Airy, that the family was settled there at 
 a very early date. Some persons of the name of Airy were 
 still living there. He then went on by Coniston and Gras- 
 rnere to Portinscale, and spent the rest of his time in expe- 
 ditions amongst the hills and visits to friends. On July 28th 
 he went to Woodbridge in Suffolk and distributed the prizes 
 to the boys of the Grammar School there. From Oct. 9th 
 to Nov. 1 2th he was again at Playford. Throughout the 
 year he was busily engaged on the Numerical Lunar Theory, 
 and found but little time for miscellaneous reading. 
 
 Of printed papers by Airy in this year the most im- 
 portant was one on the " Results deduced from the Mea- 
 sures of Terrestrial Magnetic Force in the Horizontal Plane," 
 &c. This was a long Paper, communicated to the Royal 
 Society, and published in the Phil. Trans., and was the 
 last Scientific Paper of any importance (except the Volume 
 
AT THE WHITE HOUSE, GREENWICH. 359 
 
 of the Numerical Lunar Theory) in the long list of " Papers 
 by G. B. Airy." The preparation of this Paper took much 
 time. Of miscellaneous matters : In May a Committee of 
 the Royal Society had been appointed to advise the India 
 Office as to the publication of Col. J. Herschel's pendulum 
 observations in India ; and Airy was asked to assist the 
 Committee with his advice. He gave very careful and 
 anxious consideration to the subject, and it occupied much 
 time. In the early part of the year he was asked by Sir 
 William Thomson to assist him with an affidavit in a law- 
 suit concerning an alleged infringement of one of his Pa- 
 tents for the improvement of the Compass. Airy declined 
 to make an affidavit or to take sides in the dispute, but he 
 wrote a letter from which the following is extracted : " I 
 cannot have the least difficulty in expressing my opinion 
 that you have made a great advance in the application of 
 my method of correcting the compass in iron ships, by your 
 introduction of the use of short needles for the compass- 
 cards. In my original investigations, when the whole sub- 
 ject was in darkness, I could only use existing means for 
 experiment, namely the long-needle compasses then ex- 
 isting. But when I applied mechanical theory to explana- 
 tion of the results, I felt grievously the deficiency of a theory 
 and the construction which it suggested (necessarily founded 
 on assumption that the proportion of the needle-length to 
 the other elements of measure is small) when the length of 
 the needles was really so great. I should possibly have used 
 some construction like yours, but the Government had not 
 then a single iron vessel, and did not seem disposed to urge 
 the enquiry. You, under happier auspices, have successfully 
 carried it out, and, I fully believe, with much advantage to 
 the science." He wrote a Paper for the Athenaeum and had 
 various correspondence on the subject of the Badbury Rings 
 in Dorsetshire, which he (and others) considered as identical 
 with the " Mons Badonicus " of Gildas, the site of an ancient 
 British battle. In February he was in correspondence with 
 
360 GEORGE BIDDELL AIRY. 
 
 the Astronomer Royal on Uniform Time Reckoning, and on 
 considerations relating to it. On June 6th he attended the 
 Annual Visitation of the Observatory, and brought before 
 the Board his investigations: "of the Diurnal Magnetic In- 
 equalities, and the revises of his Lunar Theory. 
 
 1886 
 
 From June 8th to July i/th he was at Play ford. And 
 again at Playford from Oct. 5th to Nov. 8th. On March 
 2/th he had an attack of gout in his right foot, which con- 
 tinued through April and into May, causing him much incon- 
 venience. He was busy with the Numerical Lunar Theory 
 up to Sept.. 2 5th, when he was reading the last proof-sheet 
 received from the printers: during this period his powers 
 were evidently failing, and there are frequent references to 
 errors discovered and corrected, and to uncertainties con- 
 nected with points of the Theory. But his great work on 
 the Numerical Lunar Theory was printed in this year : 
 and there can be no doubt that he experienced a great 
 feeling of relief when this was accomplished. He was in 
 correspondence with Prof. Adams as to the effect of his 
 reduction of the Coefficient of Lunar Acceleration on the 
 calculation of the ancient historical eclipses. He compiled 
 a Paper "On the establishment of the Roman dominion in 
 England," which was printed in 1887. He wrote a notice con- 
 cerning events in the life of Mr John Jackson of Rosthwaite 
 near Keswick, a well-known guide and much-respected au- 
 thority on matters relating to the Lake District. He also 
 wrote a short account of the connection of the history of 
 Mdlle de Queroualle with that of the Royal Observatory 
 at Greenwich. On June 4th he attended at the Annual 
 Visitation of the Observatory. 
 
AT THE WHITE HOUSE, GREENWICH. 361 
 
 1887 
 
 On May gth to nth he made a short visit to Eastbourne 
 and the neighbourhood. From June 8th to July I3th he was 
 at Play ford. From Aug. 29th to Sept. 5th he was travelling 
 in Dorsetshire and Wiltshire : he went first to Weymouth, a 
 very favourite centre for excursions with him, and afterwards 
 visited Bridport and Lyme Regis : then by Dorchester to 
 Blandford, and visited the Hod Hill, Badbury Rings, &c. : 
 at Wimborne he was much interested in the architecture of 
 the church : lastly he visited Salisbury, Old Sarum, Stone- 
 henge, &c., and returned to Greenwich. From Oct. nth to 
 Nov. 1 2th he was at Playford. During this year he partly 
 occupied himself with arranging his papers and drawings, and 
 with miscellaneous reading. But he could not withdraw his 
 thoughts from his Lunar Theory, and he still continued to 
 struggle with the difficulties of the subject, and was con- 
 stantly scheming improvements. His private accounts also 
 now gave him much trouble. Throughout his life he had 
 been accustomed to keep his accounts by double entry in 
 very perfect order. But he now began to make mistakes and 
 to grow confused, and this distressed him greatly. It never 
 seemed to occur to him to abandon his elaborate system of 
 accounts, and to content himself with simple entries of 
 receipts and expenses. This would have been utterly op- 
 posed to his sense of order, which was now more than ever 
 the ruling principle of his mind. And so he struggled with 
 his accounts as he did with his Lunar Theory till his powers 
 absolutely failed. In his Journal for this year there are 
 various entries of mental attacks of short duration and other 
 ailments ascribable to his advanced age. 
 
 The last printed "Papers by G. B. Airy" belong to this 
 year. One was the Paper before referred to " On the estab- 
 lishment of the Roman dominion in England": another was 
 on the solution of a certain Equation : and there were early 
 reminiscences of the Cambridge Tripos, &c. In February he 
 
362 GEORGE BIDDELL AIRY. 
 
 attended a little to a new edition of his Ipswich Lectures, 
 but soon handed it over to Mr H. H. Turner of the Royal 
 Observatory. On May 23rd he was drawing up suggestions 
 for the arrangement of the S^ckford School, &c., at Wood- 
 bridge. On June 4th he attended the Visitation of the Royal 
 Observatory, when a resolution was passed in favour of 
 complete photography of the star-sky. 
 
 1888 
 
 From the I4th to i6th of May he made a short expedi- 
 tion to Bournemouth, and stopped on the way home to visit 
 Winchester Cathedral. From June 27th to Aug. 3rd he was 
 at Playford ; and again from Oct. I3th to Nov. loth. During 
 the first half of the year he continued his examination of his 
 Lunar Theory, but gradually dropped it. There are several 
 references in his Journal to his feelings of pain and weakness, 
 both mental and bodily : at the end of March he had an 
 attack of gout in the fingers of his right hand. During the 
 latter part of the year he was troubled with his private ac- 
 counts, as before. He does not appear to have been engaged 
 on any miscellaneous matters calling for special notice in this 
 year. But he kept up his astronomical correspondence 
 with Lockyer on the meteorite system of planetary formation ; 
 with Pritchard on the work of the Oxford University Obser- 
 vatory ; with Adams on his Numerical Lunar Theory, &c., 
 and with others. On June 2nd he attended the Visitation of 
 the Royal Observatory. He amused himself occasionally 
 with reading his favourite subjects of history and antiquities, 
 and with looking over some of his early investigations of 
 scientific questions. 
 
 1889 
 
 On June 5th he made a one-day's excursion to Colchester. 
 From July 2nd to 2/th he was in the Cumberland Lake 
 District, chiefly at Portinscale near Keswick. While staying 
 
AT THE WHITE HOUSE, GREENWICH. 363 
 
 at Portinscale he was seized with a sudden giddiness and fell 
 upon the floor: he afterwards wrote a curious account of the 
 visions which oppressed his brain immediately after the 
 accident He returned by Solihull, where his son Osmund 
 was residing. From Oct. 4th to Nov. 8th he was at Playford. 
 While there he drew up a short statement of his general state 
 of health, adverting particularly to the loss of strength in his 
 legs and failure of his walking powers. His health seems to 
 have failed a good deal in this year : on Feb. 4th he had an 
 accidental fall, and there are several entries in his Journal of 
 mental attacks, pains in his limbs, affection of his eye-sight, 
 &c. In the early part of the year he was much engaged on 
 the history of the Airy family, particularly on that of his 
 father. In this year the White House was sold by auction 
 by its owners, and Airy purchased it on May 24th. He was 
 still in difficulties with his private accounts, but was making 
 efforts to abandon his old and elaborate system. For his 
 amusement he was chiefly engaged on Theological Notes 
 which he was compiling: and also on early optical investi- 
 gations, &c. 
 
 On June 1st he attended the Visitation of the Royal 
 Observatory, and moved a resolution that a Committee be 
 appointed to consider whether any reduction can be effected 
 in the amount of matter printed in the Volume of Observa- 
 tions of the Royal Observatory. During his tenure of office 
 he had on various occasions brought this subject before the 
 Board of Visitors, and with his usual tenacity of purpose he 
 now as Visitor pressed it upon their notice. In May he 
 zealously joined with others in an application to get for 
 Dr Huggins a pension on the Civil List. In January he 
 prepared a short Paper illustrated with diagrams to exhibit 
 the Interference of Solar Light, as used by him in his 
 Lectures at Cambridge in 1836: but it does not appear to 
 have been published. In April he received a copy of a 
 Paper by Mr Rundell, referring to the complete adoption of 
 his system of compass correction in iron ships, not only in 
 
364 GEORGE BIDDELL AIRY. 
 
 the merchant service, but also in the Navy. This was a 
 matter of peculiar gratification to Airy, who had always 
 maintained that the method of Tables of Errors, which had 
 been so persistently adhered ;to by the Admiralty, was a 
 mistake, and that sooner or later they would find it necessary 
 to adopt his method of mechanical correction. The passage 
 referred to is as follows : " The name of Sir George Airy, 
 the father of the mechanical compensation of the compass in 
 iron vessels, having just been mentioned, it may not be inap- 
 propriate to remind you that the present year is the fiftieth 
 since Sir George Airy presented to the Royal Society his 
 celebrated paper on this subject with the account of his ex- 
 periments on the ' Rainbow ' and ' Ironsides.' Fifty years is 
 a long period in one man's history, and Sir George Airy may 
 well be proud in looking back over this period to see how 
 complete has been the success of his compass investigation. 
 His mode of compensation has been adopted by all the 
 civilized world. Sir William Thomson, one of the latest and 
 perhaps the most successful of modern compass adjusters, 
 when he exhibited his apparatus in 1878 before a dis- 
 tinguished meeting in London, remarked that within the 
 last ten years the application of Sir George Airy's method 
 had become universal, not only in the merchant service, but 
 in the navies of this and other countries, and added The 
 compass and the binnacles before you are designed to 
 thoroughly carry out in practical navigation the Astronomer 
 Royal's principles." 
 
 1890 
 
 From May i/th to 24th he was on an expedition to 
 North Wales, stopping at Chester, Conway, Carnarvon, Bar- 
 mouth, and Shrewsbury. From June i8th to July 24th he 
 was at Playford ; and again from Oct. nth to Nov. I5th. 
 In this year his powers greatly failed, and he complained 
 frequently of mental attacks, weakness of limbs, lassitude, and 
 
AT THE WHITE HOUSE, GREENWICH. 365 
 
 failure of sleep. He occupied himself as usual with his books, 
 papers, and accounts ; and read Travels, Biblical History, &c., 
 but nothing very persistently. 
 
 On June 7th he attended the Visitation of the Royal 
 Observatory. From a letter addressed to him by Mr J. 
 Hartnup, of Liverpool Observatory, it appears that there had 
 grown up in the mercantile world an impression that very 
 accurate chronometers were not needed for steam ships, 
 because they were rarely running many days out of sight of 
 land : and Airy's opinion was requested on this matter. He 
 replied as follows on Mar. 3rd : " The question proposed in 
 your letter is purely a practical one. (i) If a ship is likely 
 ever to be two days out of sight of land, I think that she 
 ought to be furnished with two good chronometers, properly 
 tested. (2) For the proper testing of the rates of the chrono- 
 meters, a rating of the chronometers for three or four days in 
 a meridional observatory is necessary. A longer testing is 
 desirable." In March he was in correspondence, as one of 
 the Trustees of the Sheepshanks Fund, with the Master of 
 Trinity relative to grants from the Fund for Cambridge 
 Observatory. 
 
 1891 
 
 From June i6th to July I5th he was at Playford. And 
 again from Oct. I2th to Dec. 2nd (his last visit). Throughout 
 the year his weakness, both of brain power and muscular 
 power, had been gradually increasing, and during this stay at 
 Playford, on Nov. i ith, he fell down in his bed-room (probably 
 from failure of nerve action) and was much prostrated by the 
 shock. For several days he remained in a semi-unconscious 
 condition, and although he rallied, yet he continued very 
 weak, and it was not until Dec. 2nd that he could be removed 
 to the White House. Up to the time of his fall he had been 
 able to take frequent drives and even short walks in the 
 
366 GEORGE BIDDELL AIRY. 
 
 neighbourhood that he was so fond of, but he could take but 
 little exercise afterwards, and on or about Nov. iSth he made 
 the following note : " The saddest expedition that I have ever 
 made. We have not left home for several days." 
 
 The rapid failure of his powers during this year is well 
 exemplified by his handwriting in his Journal entries, which, 
 with occasional rallies, becomes broken and in places almost 
 illegible. He makes frequent reference to his decline in 
 strength and brain-power, and to his failing memory, but he 
 continued his ordinary occupations, made frequent drives 
 around Blackheath, and amused himself with his family history 
 researches, arrangement of papers, and miscellaneous reading : 
 and he persisted to the last with his private accounts. His 
 interest in matters around him was still keen. On June I3th 
 he was driving along the Greenwich Marshes in order to 
 track the course of the great sewer; and on August 5th he 
 visited the Crossness Sewage Works and took great interest 
 in the details of the treatment of the sewage. In March he 
 contributed, with great satisfaction, to the Fund for the 
 Portrait of his old friend Sir G. G. Stokes, with whom he had 
 had so much scientific correspondence. On July 25th an after- 
 noon party was arranged to celebrate the poth anniversary of 
 his birthday (the actual anniversary was on July 27th). 
 None of his early friends were there : he had survived them 
 all. But invitations were sent to all his scientific and private 
 friends who could be expected to come, and a large party 
 assembled. The afternoon was very fine, and he sat in the 
 garden and received his friends (many of whom had come 
 from long distances) in good strength and spirits. It was a 
 most successful gathering and was not without its meaning ; 
 for it was felt that, under the circumstances of his failing 
 powers, it was in all probability a final leave-taking. On 
 July 27th he went down to the Greenwich Parish Church 
 at 9 p.m., to be present at the illumination of the church 
 clock face for the first time a matter of local interest 
 which had necessitated a good deal of time and money. 
 
AT THE WHITE HOUSE, GREENWICH. 367 
 
 On this occasion at the request of the company assembled 
 in and around the Vestry he spoke for about a quarter 
 of an hour on Time the value of accurate time, the dis- 
 semination of Greenwich time throughout the country by 
 time-signals from the Observatory, and the exhibition of it 
 by time-balls, &c., &c., the subject to which so large a part 
 of his life had been devoted. It was a pleasant and able 
 speech and gave great satisfaction to the parishioners, 
 amongst whom he had lived for so many years. He received 
 two illuminated addresses one from the Astronomer Royal 
 and Staff of the Royal Observatory ; the other from the 
 Vorstand of the Astronomische Gesellschaft at Berlin and 
 various private letters of congratulation. The address from 
 the Staff of the Observatory was worded thus : " We, the 
 present members of the Staff of the Royal Observatory, 
 Greenwich, beg to offer you our most sincere congratulations 
 on the occasion of your QOth birthday. We cannot but feel 
 how closely associated we are with you, in that our whole 
 energies are directed to the maintenance and development of 
 that practical astronomical work, of which you essentially 
 laid the foundation. It affords us great pleasure to think 
 that after the conclusion of your life's work, you have been 
 spared to live so long under the shadow of the noble Obser- 
 vatory with which your name was identified for half a 
 century, and with which it must ever remain associated." 
 
 After his return from Playford he seemed to rally a little : 
 but he soon fell ill and was found to be suffering from hernia. 
 This necessitated a surgical operation, which was successfully 
 performed on Dec. i/th. This gave him effectual relief, and 
 after recovering from the immediate effects of the operation, 
 he lay for several days quietly and without active pain 
 reciting the English poetry with which his memory was 
 stored. But the shock was too great for his enfeebled con- 
 dition, and he died peacefully in the presence of his six 
 surviving children on Jan. 2nd, 1892. He was buried in 
 Playford churchyard on Jan. /th. The funeral procession 
 
368 GEORGE BIDDELL AIRY. 
 
 was attended at Greenwich by the whole staff of the Royal 
 Observatory, and by other friends, and at his burial there 
 were present two former Fellows of the College to which 
 he had been so deeply attached. 
 
APPENDIX. 
 
 LIST OF PRINTED PAPERS BY G. B. AIRY. 
 LIST OF BOOKS WRITTEN BY G. B. AIRY. 
 
 A. B. 24 
 
PRINTED PAPERS BY G. B. AIRY. 
 
 WITH the instinct of order which formed one of his chief 
 characteristics Airy carefully preserved a copy of every printed Paper 
 of his own composition. These were regularly bound in large quarto 
 volumes, and they are in themselves a striking proof of his wonderful 
 diligence. The bound volumes are 14 in number, and they occupy 
 a space of 2 ft. 6 in. on a shelf. They contain 518 Papers, a list of 
 which is appended, and they form such an important part of his life's 
 work, that his biography would be very incomplete without a refer- 
 ence to them. 
 
 He was very careful in selecting the channels for the publication 
 of his Papers. Most of the early Papers were published in the 
 Transactions of the Cambridge Philosophical Society, but several of 
 the most important, such as his Paper " On an inequality of long 
 period in the motions of the Earth and Venus," were published in 
 the Philosophical Transactions of the Royal Society, and others, 
 such as the articles on " The Figure of the Earth," " Gravitation," 
 " Tides and Waves," &c., were published in Encyclopaedias. After 
 his removal to Greenwich nearly all his Papers on scientific subjects 
 (except astronomy), such as Tides, Magnetism, Correction of the 
 Compass, &c., &c., were communicated to the Royal Society, and 
 were published in the Philosophical Transactions. But everything 
 astronomical was reserved for the Royal Astronomical Society. His 
 connection with that Society was very close : he had joined it in its 
 earliest days (the date of his election was May gth, 1828), and 
 regarded it as the proper medium for the discussion of current 
 astronomical questions, and for recording astronomical progress. 
 He was unremitting in his attendance at the Monthly Meetings of 
 the Society, and was several times President. In the Memoirs of 
 the Society 35 of his Papers are printed, and in addition 129 Papers 
 in the Monthly Notices. In fact a meeting of the Society rarely 
 
PRINTED PAPERS BY G. B. AIRY. 371 
 
 passed without some communication from him, and such was his 
 wealth of matter that sometimes he would communicate as many as 
 3 Papers on a single evening. For the publication of several short 
 mathematical Papers, and especially for correspondence on disputed 
 points of mathematical investigation, he chose as his vehicle the 
 Philosophical Magazine, to which he contributed 32 Papers. 
 Investigations of a more popular character he published in the 
 Athenaeum, which he also used as a vehicle for his replies to attacks 
 on his work, or on the Establishment which he conducted : in all he 
 made 55 communications to that Newspaper. To various Societies, 
 such as the Institution of Civil Engineers, the British Association, 
 the Royal Institution, &c., he presented Papers or made com- 
 munications on subjects specially suited to each ; and in like manner 
 to various Newspapers : there were 58 Papers in this category. In 
 so long an official life there would naturally be a great number of 
 Official Reports, Parliamentary Returns, &c., and these, with other 
 miscellaneous Papers printed for particular objects and for a limited 
 circulation, amounted in all to 141. Under this head come his 
 Annual Reports to the Board of Visitors, which in themselves con- 
 tain an extremely full and accurate history of the Observatory during 
 his tenure of office. There are 46 of these Reports, and they would 
 of themselves form a large volume of about 740 pages. 
 
 242 
 
The following summary of his Printed Papers shews the manner 
 in which they were distributed : 
 
 SUMMARY OF PRINTED PAPERS BY G. B. AIRY. 
 
 Number of 
 
 Papers. 
 
 In the Transactions of the Cambridge Philosophical Society 30 
 
 In the Philosophical Transactions of the Royal Society . .^ ' 29 
 
 In the Proceedings of the Royal Society . . . , 9 
 
 In the Memoirs of the Royal Astronomical Society . . 35 
 
 In the Monthly Notices of the Royal Astronomical Society . 129 
 
 In the Philosophical Magazine and Journal . . . ' ' ! . " 32 
 
 In the Athenaeum . . . . . .' . . 55 
 
 In Encyclopaedias, and in various Newspapers and Trans- 
 actions . . . . . ... .v 58 
 
 In Official Reports, Addresses, Parliamentary Returns, 
 Evidence before Committees, Lectures, Letters, 
 
 Sundry Treatises, and Papers 141 
 
 Total 518 
 
PRINTED PAPERS BY G. B. AIRY. 
 
 Date when read 
 or published. Title of Paper. Where published. 
 
 1822 Nov. 25 On the use of Silvered Glass for the Mirrors Camb. Phil. Soc. 
 
 of Reflecting Telescopes. 
 1824 Mar. 15 On the Figure assumed by a Fluid Homo- Camb. Phil. Soc. 
 
 geneous Mass, whose Particles are acted 
 
 on by their mutual Attraction, and by 
 
 small extraneous Forces. 
 1824 May 17 On the Principles and Construction of the Camb. Phil. Soc. 
 
 Achromatic Eye-Pieces of Telescopes, 
 
 and on the Achromatism of Microscopes. 
 
 1824 Trigonometry. Encycl. Metrop. 
 
 1825 Feb. 21 On a peculiar Defect in the Eye, and a Camb. Phil. Soc. 
 
 mode of correcting it. 
 
 1825 May 2 On the Forms of the Teeth of Wheels. Camb. Phil. Soc. 
 
 1826 May 8 On Laplace's Investigation of the Attraction Camb. Phil. Soc. 
 
 of Spheroids differing little from a Sphere. 
 1826 June 15 On the Figure of the Earth. Phil. Trans. 
 
 1826 Nov. 26 On the Disturbances of Pendulums and Camb. Phil. Soc. 
 
 Balances, and on the Theory of Escape- 
 ments. 
 
 1827 Feb. 15 Remarks on a Correction of the Solar Phil. Trans. 
 
 Tables,, required by Mr South's observa- 
 tions. 
 
 1827 May 9 On some Passages in Mr Ivory's Remarks Phil. Mag. 
 on a Memoir by M. Poisson relating to 
 the Attraction of Spheroids. 
 May 14 On the Spherical Aberration of the Eye- Camb. Phil. Soc. 
 
 pieces of Telescopes. 
 
 On the corrections in the elements of Phil. Trans. 
 Delambre's Solar Tables required by the 
 observations made at the Royal Observa- 
 tory, Greenwich. 
 
 l82 7JMay 21 
 1827 Dec. 6 
 
374 
 
 APPENDIX. 
 
 Date when read 
 or published. 
 
 Title of Paper. 
 
 1828 Feb. 26 Address to the Members of the Senate, on 
 an Improvement in the Position of the 
 Plumian Professor. '. 
 
 1828 Nov. 24 On the Longitude of the Cambridge Ob- 
 
 servatory. 
 
 1829 Nov. 13 On a method of determining the Mass of 
 
 the Moon from Transit Observations of 
 Venus near her inferior conjunction. 
 1829 Nov. 16 On a Correction requisite to be applied to 
 the Length of a Pendulum consisting of 
 a Ball suspended by a fine Wire. 
 
 1829 Dec. 14 On certain Conditions under which a 
 
 Perpetual Motion is possible. 
 
 1830 Aug. 17 Figure of the Earth. 
 
 1831 Feb. 21 On the Nature of the Light in the Two 
 
 Rays produced by the Double Refraction 
 
 of Quartz. 
 
 1831 Apr. 1 8 Addition to the above Paper. 
 1831 Nov. 14 On a remarkable Modification of Newton's 
 
 Rings. 
 
 1831 Nov. 24 On an inequality of long period in the 
 
 motions of the Earth and Venus. 
 
 1832 Jan. 2 Translation of Encke's Dissertation (on 
 
 Encke's Comet) contained in Nos. 210 
 and 2H of the Astronomische Nach- 
 richten. 
 
 1832 Mar. 5 On a new Analyzer, and its use in Experi- 
 ments of Polarization. 
 
 1832 Mar. 19 On the Phenomena of Newton's Rings 
 when formed between two transparent 
 Substances of different refractive Powers. 
 
 1832 May 2 Report on the Progress of Astronomy 
 during the present century. 
 
 1832 Oct. Report of the Syndicate of the Cambridge 
 
 Observatory. 
 
 1833 Feb. 2 Remarks on Mr Potter's Experiment on 
 
 Interference. 
 
 1833 Apr. 12 On the Mass of Jupiter, as determined 
 from the Observation of Elongations of 
 the Fourth Satellite. 
 
 1833 Syllabus of a Course of Experimental 
 
 Lectures. 
 
 1833 May 7 On the Calculation of Newton's Experi- 
 ments on Diffraction. 
 
 Where published. 
 
 Camb. Phil. Soc. 
 
 Astr. Soc. 
 (Memoirs.) 
 
 Camb. Phil. Soc. 
 
 Camb. Phil. Soc. 
 
 Encycl. Metrop. 
 Camb. Phil. Soc. 
 
 Camb. Phil. Soc. 
 Camb. Phil. Soc. 
 
 Phil. Trans. 
 
 Camb. Phil. Soc. 
 Camb. Phil. Soc. 
 
 Trans. Brit. Ass. 
 
 Phil. Mag. 
 
 R. Astr. Soc. 
 (Memoirs.) 
 
 Camb. Phil. Soc. 
 
PRINTED PAPERS BY G. B. AIRY. 
 
 375 
 
 Date when read 
 or published. Title of Paper. 
 
 1833 May 7 Remarks on Sir David Brewster's Paper 
 "On the Absorption of Specific Rays" 
 &c. 
 
 1833 May 1 6 Results of the Repetition of Mr Potter's 
 Experiment of interposing a Prism in 
 the Path of Interfering Light. 
 
 1833 May On a supposed black bar formed by Dif- 
 fraction. 
 
 1833 June 20 Report on Mr Barlow's Fluid- Lens Tele- 
 
 scope. 
 
 1834 Mar. 14 Continuation of Researches into the Value 
 
 of the Mass of Jupiter, by observation of 
 the Elongations of the Fourth Satellite. 
 
 1834 Apr. 14 On the Latitude of Cambridge Obser- 
 vatory. 
 
 1834 June Report of the Syndicate of the Cambridge 
 Observatory. 
 
 1834 June 13 On the Position of the Ecliptic, as inferred 
 from Transit and Circle Observations 
 made at Cambridge Observatory in the 
 year 1833. 
 
 1834 June 13 Observations of the Solar Eclipse of July 
 1 6th, 1833, made at Cambridge Observa- 
 tory, and Calculations of the Observa- 
 tions. 
 
 1834 Nov. 24 On the Diffraction of an Object-Glass with 
 Circular Aperture. 
 
 1834 Dec. 3 On the Calculation of the Perturbations 
 
 of the Small Planets and the Comets of 
 short period. 
 
 1835 May 8 Continuation of Researches into the Value 
 
 of Jupiter's Mass. 
 1835 June Report of the Syndicate of the Cambridge 
 
 Observatory. 
 1835 June 12 On the Position of the Ecliptic, as inferred 
 
 from Observations with the Cambridge 
 
 Transit and Mural Circle, made in the 
 
 year 1834. 
 1835 June 12 On the Time of Rotation of Jupiter. 
 
 1836 Feb. 12 Speech on delivering the Medal of the 
 R. Astr. Soc. to Sir John Herschel. 
 
 1836 June 4 Report of the Astronomer Royal to the 
 Board of Visitors. 
 
 Where published. 
 Phil. Mag. 
 
 Phil. Mag. 
 
 Phil. Mag. 
 
 R. Soc. (Proc.) 
 
 R. Astr. Soc. 
 (Memoirs.) 
 
 Camb. Phil. Soc. 
 
 R. Astr. Soc. 
 (Memoirs.) 
 
 R. Astr. Soc. 
 (Memoirs.) 
 
 Camb. Phil. Soc. 
 
 Naut. Aim. 
 (1837, App.) 
 
 R. Astr. Soc. 
 (Memoirs.) 
 
 R. Astr. Soc. 
 (Memoirs.) 
 
 R. Astr. Soc. 
 
 (Memoirs.) 
 R. Astr. Soc. 
 
 (Proc.) 
 
376 
 
 APPENDIX. 
 
 Date when read 
 or published. 
 
 Title of Paper. 
 
 Where published. 
 
 1836 June 9 Report upon a Letter (on a Systematic R. Soc. (Proc.) 
 
 Course of Magnetic Observations) ad- 
 dressed by M. le Baron de Humboldt to 
 His Royal Highness the President of 
 the Royal Society (by S. Hunter Christie 
 and G. B. Airy). i. 
 
 !$37 Jan. 13 Continuation of Researches into the Value R. Astr. Soc. 
 of Jupiter's Mass. (Memoirs.) 
 
 1837 Feb. 10 Speech on delivering the Medal of the R. Astr. Soc. 
 
 R. Astr. Soc. to Professor Rosenberger. 
 1837 Mar. 10 Results of the Observations of the Sun, 
 Moon, and Planets, made at Cambridge 
 Observatory in the years 1833, 1834, and 
 
 1837 May 12 On the Position of the Ecliptic, as inferred 
 from Observations with the Cambridge 
 Transit and Mural Circle, made in the 
 year 1835. 
 
 1837 June 3 Report of the Astronomer Royal to the 
 Board of Visitors. 
 
 1837 Sept. 9 Address delivered in the Town Hall of 
 Neath. 
 
 1837 Nov. 10 On the Parallax of a Lyrae. 
 
 (Proc.) 
 
 R. Astr. Soc. 
 (Memoirs.) 
 
 R. Astr. Soc. 
 (Memoirs.) 
 
 R. Astr. Soc. 
 (Memoirs.) 
 
 1838 Feb. 10 Address to the Earl of Burlington on 
 
 Religious Examination in the University 
 
 of London. 
 1838 Mar. 26 On the Intensity of Light in the neighbour- Camb. Phil. Soc. 
 
 hood of a Caustic. 
 1838 June 2 Report of the Astronomer Royal to the 
 
 Board of Visitors. 
 
 1838 Dec. 14 A Catalogue of 726 Stars, deduced from R. Astr. Soc. 
 
 the Observations made at the Cambridge (Memoirs.) 
 Observatory, from 1828 to 1835 ; reduced 
 to January I, 1830. 
 
 1839 Apr. 25 Account of Experiments on Iron-built Phil. Trans. 
 
 Ships, instituted for the purpose of dis- 
 covering a correction for the deviation 
 of the Compass produced by the iron of 
 the Ships. 
 
 1839 June i Report of the Astronomer Royal to the 
 Board of Visitors. 
 
 1839 Nov. 8 On the Determination of the Orbits of R. Astr. Soc. 
 Comets, from Observations. (Memoirs.) 
 
PRINTED PAPERS BY G. B. AIRY. 
 
 377 
 
 Date when read 
 or published. Title of Paper. 
 
 1839 Article " Gravitation." 
 
 1839 Article "Greenwich Observatory." 
 
 1840 Mar. 2 On a New Construction of the Going-Fusee. 
 1840 Mar. 13 On the Regulator of the Clock-work for 
 
 effecting uniform Movement of Equa- 
 toreals. 
 
 1840 May 15 On the Correction of the Compass in Iron- 
 built Ships. 
 
 1840 Results of Experiments on the Disturbance 
 
 of the Compass in Iron-built Ships. 
 
 1840 June 6 Report of the Astronomer Royal to the 
 Board of Visitors. 
 
 1840 June 1 8 On the Theoretical Explanation of an ap- 
 parent new Polarity in Light. 
 
 1840 Nov. 19 Supplement to the above Paper. 
 
 1840 Dec. 4 On the Diffraction of an Annular Aperture. 
 
 1840 Dec. 9 Remarks on Professor Challis's Investi- 
 
 gation of the Motion of a Small Sphere 
 vibrating in a Resisting Medium. 
 
 1841 Jan. 20 Correction to the above Paper "On the 
 
 Diffraction," c. 
 
 1841 Mar. 22 Remarks on Professor Challis's Reply to 
 Mr Airy's Objections to the Investi- 
 gation of the Resistance of the Atmo- 
 sphere to an Oscillating Sphere. 
 
 1841 June 5 Report of the Astronomer Royal to the 
 Board of Visitors. 
 
 1841 July 10 Reply to Professor Chain's, on the Investi- 
 gation of the Resistance of the Air to an 
 Oscillating Sphere. 
 
 1841 Oct. 26 Extraordinary Disturbance of the Magnets. 
 
 1841 Nov. 25 On the Laws of the Rise and Fall of the 
 Tide in the River Thames. 
 
 1841 Dec. 21 Report of the Commissioners appointed to 
 
 consider the steps to be taken for Res- 
 toration of the Standards of Weight and 
 Measure. 
 
 1842 Apr. 16 On the IKTIS of Diodorus. 
 
 1842 May 13 Account of the Ordnance Zenith Sector. 
 
 Where published. 
 
 Penny Cyclop. 
 Penny Cyclop. 
 Camb. Phil. Soc. 
 R. Astr. Soc. 
 
 Un. Serv. Journ. 
 
 (Proc.) 
 J. Weale. 
 
 Phil. Trans. 
 
 Phil. Trans. 
 Phil. Mag. 
 Phil. Mag. 
 
 Phil. Mag. 
 Phil. Mag. 
 
 Phil. Mag. 
 
 Phil. Trans. 
 
 1842 June 4 Report of the Astronomer Royal to the 
 
 Board of Visitors. 
 1842 Nov. ii Observations of the Total Solar Eclipse of 
 
 1842 July 7. 
 
 Athenaeum. 
 R. Astr. Soc. 
 (Proc.) 
 
 R. Astr. Soc. 
 (Memoirs.) 
 
378 
 
 APPENDIX. 
 
 Date when read 
 or published. 
 
 Title of Paper. 
 
 1842 Dec. i Remarks on the Present State of HatclifFs 
 Charity (Greenwich).. 
 
 1842 Article on Tides and Waves. 
 
 1843 Mar. 2 On the Laws of Individual Tides at South- 
 
 ampton and at Ipswich. 
 
 1843 Apr. 29 On Monetary and Metrical Systems, i. 
 
 1843 J une 3 Report of the Astronomer Royal to the 
 Board of Visitors. 
 
 1843 Sept. 25 Address to the Individual Members of the 
 Board of Visitors of the Royal Observa- 
 tory (proposing the Altazimuth). 
 
 1843 Oct. 6 Account of the Northumberland Equatoreal 
 and Dome, attached to the Cambridge 
 Observatory. 
 
 1843 Nov. 10 Address and Explanation of the proposed 
 
 Altitude and Azimuth Instrument to the 
 Board of Visitors of the Royal Observa- 
 tory. 
 
 1844 June i Report of the Astronomer Royal to the 
 
 Board of Visitors. 
 
 1844 Dec. 12 On the Laws of the Tides on the Coasts of 
 
 Ireland, as inferred from an extensive 
 series of observations made in connec- 
 tion with the Ordnance Survey of Ireland. 
 
 1845 J an - Io On the Flexure of a Uniform Bar sup- 
 
 ported by a number of equal Pressures 
 
 applied at equidistant points, &c. 
 1845 Feb. 14 Speech on delivering the Medal of the 
 
 R. Astr. Soc. to Capt. Smyth. 
 1845 May 9 On a New Construction of the Divided 
 
 Eye-Glass Double-Image Micrometer. 
 1845 J un e 7 Report of the Astronomer Royal to the 
 
 Board of Visitors. 
 
 1845 July 21 On Wexford Harbour. 
 
 1846 Report of the Gauge Commissioners. And 
 
 letter to Sir E. Ryan. 
 
 1846 May 7 On the Equations applying to Light under 
 the action of Magnetism. 
 
 1846 May 12 Remarks on Dr Faraday's Paper on Ray- 
 vibrations. 
 
 1846 May 25 On a Change in the State of an Eye 
 affected with a Mai-formation. 
 
 1846 June 6 Report of the Astronomer Royal to the 
 Board of Visitors. 
 
 "Where published. 
 Private. 
 
 Encyc. Metrop. 
 Phil. Trans. 
 
 Athenseum. 
 
 Phil. Trans. 
 
 R. Astr. Soc. 
 (Memoirs.) 
 
 R. Astr. Soc. 
 
 (Proc.) 
 R. Astr. Soc. 
 
 (Memoirs.) 
 
 Phil. Mag. 
 Phil. Mag. 
 Camb. Phil. Soc. 
 
PRINTED PAPERS BY G. B. AIRY. 
 
 379 
 
 Date when read 
 or published. 
 
 Title of Paper. 
 
 1846 June Account of the Measurement of an Arc of 
 Longitude between the Royal Observa- 
 tory of Greenwich and the Trigonometri- 
 cal Station of Feagh Main, in the Island 
 of Valentia. 
 
 1846 July 25 Letter to Sir Robert Harry Inglis, Bart., 
 M.P., in answer to Sir James South's 
 attack on the Observations at the Green- 
 wich Observatory. 
 
 1846 Nov. On the Bands formed by the partial Inter- 
 ception of the Prismatic Spectrum. 
 
 1846 Nov. 13 Account of some circumstances historically 
 
 connected with the Discovery of the 
 Planet exterior to Uranus. 
 
 1847 Jan. 8 Reduction of the Observations of H alley's 
 
 Comet made at the Cambridge Obser- 
 vatory in the years 1835 and 1836. 
 
 1847 Jan. 8 On a proposed Alteration of Bessel's Me- 
 thod for the Computation of the Correc- 
 tions by which the Apparent Places of 
 Stars are derived from the Mean Places. 
 
 1847 Feb. On Sir David Brewster's New Analysis of 
 Solar Light. 
 
 1847 Feb. 20 On the Name of the New Planet. 
 
 1847 Feb. 27 Mr Adams and the New Planet. 
 
 1847 Plan of the Buildings and Grounds of the 
 
 Royal Observatory, Greenwich, with Ex- 
 planation and History. 
 
 1847 May 14 Explanation of Hansen's Perturbations of 
 the Moon by Venus. 
 
 1847 June 5 Report of the Astronomer Royal to the 
 Board of Visitors. 
 
 1847 Nov. 30 Address to the Individual Members of the 
 Board of Visitors of the Royal Observa- 
 tory. (Zenith Tube.) 
 
 1847 Dec. 10 Results deduced from the Occultations of 
 
 Stars and Planets by the Moon, ob- 
 served at Cambridge Observatory from 
 1830 to 1835. 
 
 1848 Feb. ii Abstract of Struve's " Etudes d'Astronomie 
 
 Stellaire." 
 
 1848 Mar. 13 Syllabus of Lectures on Astronomy to be 
 delivered at the Temperance Hall, 
 Ipswich. 
 
 Where published. 
 
 R. Astr. Soc. 
 (Month. Not.) 
 
 Athenaeum. 
 
 Phil. Mag. 
 
 R. Astr. Soc. 
 (Memoirs.) 
 
 R. Astr. Soc. 
 (Memoirs.) 
 
 R. Astr. Soc. 
 (Memoirs.) 
 
 Phil. Mag. 
 
 Athenaeum. 
 Athenaeum. 
 
 R. Astr. Soc. 
 (Month. Not.) 
 
 R. Astr. Soc. 
 (Memoirs.) 
 
 R. Astr. Soc. 
 
 (Month. Not.) 
 
380 
 
 APPENDIX. 
 
 Date when read 
 or published. 
 
 Title of Paper. 
 
 1848 Apr. 10 Remarks on Prof. Challis's Theoretical 
 Determination of the Velocity of Sound. 
 
 1848 May 8 Supplement to a Paper on the Intensity of 
 Light in the neighbourhood of a Caustic. 
 
 1848 May 12 Address to Individual Members of the 
 Board of Visitors. (New Transit Circle, 
 Reflex Zenith Tube, c.) 
 
 1848 June 3 Report of the Astronomer Royal to the 
 Board of Visitors. 
 
 1848 June 9 Corrections of the Elements of the Moon's 
 Orbit, deduced from the Lunar Observa- 
 tions made at the Royal Observatory of 
 Greenwich from 1750 to 1830. 
 
 1848 Aug. 9 Explanation of a proposed construction of 
 Zenith Sector : addressed to the Board 
 of Visitors of the Royal Observatory, 
 . Greenwich. 
 
 1848 Oct. 14 On the Construction of Chinese Balls. 
 
 1849 Description of the Instruments and Process 
 
 used in the Photographic self-registra- 
 tion of the Magnetical and Meteorologi- 
 cal Instruments at the Royal Observa- 
 tory, Greenwich. 
 
 1849 Description of the Altitude and Azimuth 
 
 Instrument erected at the Royal Obser- 
 vatory, Greenwich, in the year 1847. 
 
 1849 Astronomy. (Tract written for the Scien- 
 
 tific Manual.) 
 
 1849 Mar. 9 Substance of the Lecture delivered by the 
 Astronomer Royal on the large Reflecting 
 Telescopes of the Earl of Rosse and Mr 
 Lassell. 
 
 1849 J une On a difficulty in the Problem of Sound. 
 
 1849 June 2 Report of the Astronomer Royal to the 
 Board of Visitors. 
 
 1849 June 8 On Instruments adapted to the Measure of 
 small Meridional Zenith Distances. 
 
 1849 Nov. 9 Results of the Observations made by the 
 Rev. Fearon Fallows at the Royal Ob- 
 servatory, Cape of Good Hope, in the 
 years 1829, 1830, 1831. 
 
 1849 Nov. 9 On Bell's Calculating Machine, and on 
 Lord Rosse's Telescope. 
 
 1849 Nov. 10 On the Exodus of the Israelites. 
 
 Where published. 
 Phil. Mag. 
 
 Camb. Phil. Soc. 
 
 R. Astr. Soc. 
 (Memoirs.) 
 
 Athenaeum. 
 
 R. Astr. Soc. 
 (Month. Not.) 
 
 Phil. Mag. 
 
 R. Astr. Soc. 
 
 (Month. Not.) 
 R. Astr. Soc. 
 (Memoirs.) 
 
 R. Astr. Soc. 
 
 (Month. Not.) 
 Athenaeum. 
 
PRINTED PAPERS BY G. B. AIRY. 
 
 381 
 
 Date when read 
 or published. Title of Paper. Where published. 
 
 1849 Dec. 14 On the Method of observing and recording R. Astr. Soc. 
 
 Transits, lately introduced in America, &c. (Month. Not.) 
 
 1850 Jan. 10 On a problem of Geodesy. Phil. Mag. 
 1850 Feb. 8 Address on presenting the Medal of the R. Astr. Soc. . 
 
 R. Astr. Soc. to M. Otto von Struve. (Month. Not.) 
 
 1850 Mar. 15 On the Present State and Prospects of the R. Inst. 
 Science of Terrestrial Magnetism. 
 
 1850 Mar. 16 On the Exodus of the Israelites. Athenaeum. 
 
 1850 Mar. 30 On the Exodus of the Israelites. Athenaeum. 
 
 1850 May 10 Statement concerning Assistance granted R. Astr. Soc. 
 
 by the Admiralty to Hansen Also on (Month. Not.) 
 
 Henderson's numbers for the teeth of 
 
 wheels. 
 
 1850 May 10 On the Weights to be given to the sepa- R. Astr. Soc. 
 rate Results for Terrestrial Longitudes, (Memoirs.) 
 determined by the Observation of Tran- 
 sits of the Moon and Fixed Stars. 
 
 1850 June i Report of the Astronomer Royal to the 
 Board of Visitors. 
 
 1850 June 14 Letter from Hansen on his Lunar Tables. R. Astr. Soc. 
 
 Valz on an arrangement of double-image (Month. Not.) 
 micrometer. On the Computation of 
 Longitude from Lunar Transits. 
 
 1850 Dec. 13 On a Method of regulating the Clock-work R. Astr. Soc. 
 
 for Equatoreals. (Month. Not.) 
 
 1850 Dec. 13 Supplement to a Paper "On the Regulation R. Astr. Soc. 
 of the Clock-work for effecting Uniform (Memoirs.) 
 Movement of Equatoreals." 
 
 1850 Dec. 27 On the Relation of the Direction of the Phil. Trans. 
 
 Wind to the Age of the Moon, as inferred 
 from Observations made at the Royal 
 Observatory, Greenwich, from 1840 Nov. 
 to 1847 Dec. 
 
 1851 Jan. 14 Remarks on Mr Wyatt's Paper on the Con- Inst. C. E. 
 
 struction of the Building for the Exhibi- (Minutes.) 
 tion of the Works of Industry of all Na- 
 tions in 1851. 
 
 1851 Feb. 15 Address on presenting the Medal of the R. Astr. Soc. 
 
 R. Astr. Soc. to Dr Annibale de (Month. Not.) 
 Gasparis. 
 
 1851 Mar. 28 Letter to Professor Challis regarding the 
 Adams Prize. 
 
 1851 Mar. 29 On Caesar's Place of Landing in Britain. Athenaeum. 
 
 1851 Suggestions to Astronomers for the Obser- Brit. Assoc. 
 
382 
 
 APPENDIX. 
 
 Date when read 
 or published. 
 
 Title of Paper. 
 
 vation of the Total Eclipse of the Sun on 
 July 28, 1851. 
 
 1851 Apr. n On the Determination of the probable Sta- 
 bility of an Azimuth al Circle by Observa- 
 tions of Stars and of a permanent Colli- 
 mator. 
 
 1 85 1 May 2 On the Total Solar Eclipse of 1 85 1, July 28. 
 (Lecture.) 
 
 1851 May 9 On the Vibration of a Free Pendulum in an 
 Oval differing little from a Straight Line. 
 
 1851 June 7 Report of the Astronomer Royal to the 
 Board of Visitors. 
 
 185 1 July 2 The President's Address to the Twenty-first 
 Meeting of the British Association for 
 the Advancement of Science, Ipswich. 
 
 1851 Oct. 17 On Julius Caesar's Expedition against Eng- 
 land, in relation to his places of de- 
 parture and landing. 
 
 1851 Nov. 14 Account of the Total Eclipse of the Sun on 
 1851, July 28, as observed at Gottenburg, 
 at Christiania, and at Christianstadt. 
 
 1851 Dec. 13 On the Geography of the Exodus. 
 
 1852 Jan. 9 On the Solar Eclipse of July 28, 1851. 
 
 1852 On the Place of Caesar's Departure from 
 
 Gaul for the Invasion of Britain, and 
 the Place of his Landing in Britain, 
 with an Appendix on the Battle of 
 Hastings. 
 
 1852 On a New Method of computing the Per- 
 
 turbations of Planets, by J. F. Encke 
 translated and illustrated with notes by 
 G. B. Airy. 
 
 1852 June 5 Report of the Astronomer Royal to the 
 
 Board of Visitors. 
 
 1853 Feb. 3 On the Eclipses of Agathocles, Thales, 
 
 and Xerxes. 
 
 1853 Feb. 4 Lecture on the results of recent calcula- 
 tions on the Eclipse of Thales and 
 Eclipses connected with it. 
 
 1853 May 3 Address to the Individual Members of the 
 Board of Visitors of the Royal Observa- 
 tory, Greenwich. (Lunar Reductions.) 
 
 1853 May 14 On Decimal Coinage. 
 
 Where published. 
 
 R. Astr. Soc. 
 (Month. Not.) 
 
 R. Inst. 
 
 R. Astr. Soc. 
 (Memoirs.) 
 
 Athenaeum. 
 Naut. Mag. 
 
 R. Astr. Soc. 
 (Memoirs.) 
 
 Athenaeum. 
 [R. Astr. Soc. 
 I (Month. Not.) 
 
 Soc. of Antiq. 
 (Memoirs.) 
 
 Naut. Aim. 1856, 
 App. 
 
 Phil. Trans. 
 R. Inst. 
 
 Athenaeum. 
 
PRINTED PAPERS BY G. B. AIRY. 
 
 383 
 
 Date when read 
 or published. 
 
 Title of Paper. 
 
 1853 June 4 Report of the Astronomer Royal to the 
 Board of Visitors. 
 
 1853 June Lecture on the Determination of the Lon- 
 gitude of the Observatory of Cambridge 
 by means of Galvanic Signals. 
 
 1853 Sept. 10 On Decimal Coinage. 
 
 1853 Dec. 14 Description of the Transit Circle of the 
 Royal Observatory, Greenwich. (App. 
 Gr. Observ. 1852.) 
 
 1853 Dec. 14 Regulations of the Royal Observatory, 
 
 Greenwich. (App. Gr. Observ. 1852.) 
 
 1854 Jan. 14 On the Telegraphic Longitude of Brussels. 
 1854 Feb. 10 Address on presenting the Gold Medal of 
 
 the R. Astr. Soc. to Mr Charles Riimker. 
 
 1854 Feb. 25 On Reforms in the University of Cam- 
 bridge. 
 
 1854 Apr. 15 Letters relating to "The Late M. Mauvais." 
 
 1854 June 3 Report of the Astronomer Royal to the 
 Board of Visitors. 
 
 1854 Sept. The Deluge. 
 
 1854 Oct. 28 On the Correction of the Compass in Iron 
 Ships. (Scoresby's Experiments.) 
 
 1854 Nov. 10 On the Difference of Longitude between 
 
 the Observatories of Brussels and Green- 
 wich, as determined by Galvanic Signals. 
 
 1855 Jan. i Lecture at S. Shields on the Pendulum 
 
 Experiments in the Harton Pit, and 
 Letter on the Results. 
 
 1855 Feb. 2 Lecture on the Pendulum Experiments 
 lately made in the Harton Colliery for 
 ascertaining the mean Density of the 
 Earth. 
 
 1855 Feb. 3 On the Correction of the Compass in Iron 
 Ships. (Remarks on Dr Scoresby's In- 
 vestigations.) 
 
 1855 Address on presenting the Medal of the 
 
 R. Astr. Soc. to the Rev. William Rutter 
 Dawes. 
 
 1855 Feb. 15 On the Computation of the Effect of the 
 Attraction of Mountain Masses, as dis- 
 turbing the Apparent Astronomical Lati- 
 tude of Stations in Geodetic Surveys. 
 
 1855 June 2 Report of the Astronomer Royal to the 
 Board of Visitors. 
 
 Where published. 
 
 R. Astr. Soc. 
 (Month. Not.) 
 
 Athenaeum. 
 
 Athenaeum. 
 R. Astr. Soc. 
 
 (Month. Not.) 
 Athenaeum. 
 
 Liter. Gaz. 
 
 Private. 
 Athenaeum. 
 
 R. Astr. Soc. 
 (Memoirs.) 
 
 R. Inst. 
 
 Athenaeum. 
 
 R. Astr. Soc. 
 (Month. Not.) 
 
 Phil. Trans. 
 
APPENDIX. 
 
 Date when read 
 or published. 
 
 Title of Paper. 
 
 1855 Oct. 18 Address to the Individual Members of the 
 Board of .Visitors of the Royal Observa- 
 tory, Greenwich. (^Tquatoreal.) 
 
 1855 Nov. 21 Remarks upon certain Cases of Personal 
 Equation which appear to have hitherto 
 escaped notice, accompanied with a Table 
 of Results. 
 
 1855 Nov. 22 Discussion of the Observed Deviations of 
 the Compass in several Ships, Wood- 
 built and Iron-built : with a General 
 Table for facilitating the examination of 
 Compass-Deviations. 
 
 1855 Description of the Reflex Zenith Tube of 
 
 the Royal Observatory, Greenwich. (App. 
 to the Greenwich Obs. for 1854.) 
 
 1856 Jan. 9 On Professor Peirce's Criterion for dis- 
 
 cordant observations. 
 
 1856 Jan. 24 Account of Pendulum Experiments under- 
 taken in the Hartori Colliery, for the 
 purpose of determining the Mean Den- 
 sity of the Earth. 
 
 1856 June 7 Report of the Astronomer Royal to the 
 Board of Visitors. 
 
 1856 Aug. 25 On Scheutz's Calculating Machine. 
 
 1856 Aug. 30 Science and the Government. (Reply to 
 
 statements in the Morning Chronicle 
 about the instrumental equipment of the 
 Royal Observatory.) 
 
 1857 May 8 On the Means which will be available for 
 
 correcting the Measure of the Sun's Dis- 
 tance in the next twenty-five years. 
 1857 May 12 Knowledge expected in Computers and 
 
 Assistants in the Royal Observatory. 
 1857 June 6 Report of the Astronomer Royal to the 
 
 Board of Visitors. 
 1857 June 12 On the Eclipse of Agathocles, the Eclipse 
 
 at Larissa, and the Eclipse of Thales. 
 
 With an Appendix on the Eclipse of 
 
 Stiklastad. 
 1857 June 1 8 Account of the Construction of the New 
 
 National Standard of Length, and of its 
 
 principal copies. 
 1857 Dec. 5 Letter to the Vice-Chancellor of Cambridge 
 
 University regarding Smith's Prizes. 
 
 Where published. 
 
 R. Astr. Soc. 
 (Month. Not.) 
 
 Phil. Trans. 
 
 Astr. Journ. 
 
 (Cambr.) 
 
 Phil. Trans. 
 
 Phil. Mag. 
 Athenaeum. 
 
 R. Astr. Soc. 
 (Month. Not.) 
 
 R. Astr. Soc. 
 (Memoirs.) 
 
 Phil. Trans. 
 
PRINTED PAPERS BY G. B. AIRY. 
 
 385 
 
 Date when read 
 or published. 
 
 1857 Dec. 7 
 
 Title of Paper. 
 
 On the Substitution of Methods founded 
 Ordinary Geometry for Methods 
 
 on 
 
 based on the General Doctrine of Pro- 
 portions, in the treatment of some Geo- 
 metrical Problems. 
 
 1857 Description of the Galvanic Chronographic 
 
 Apparatus of the Royal Observatory, 
 Greenwich. 
 
 1858 Mar. 8 Suggestions for Observation of the Annular 
 
 Eclipse of the Sun on 1858, March 14-15. 
 
 1858 Mar. 12 Note on Oltmann's Calculation of the 
 Eclipse of Thales. Also On a Method 
 of very approximately representing the 
 Projection of a Great Circle upon M cr- 
 eator's Chart. 
 
 1858 May The Atlantic Cable Problem. 
 
 1858 May 20 Report of the Ordnance Survey Commis- 
 sion ; together with Minutes of Evidence 
 and Appendix. 
 
 1858 June 5 Report of the Astronomer Royal to the 
 Board of Visitors. 
 
 1858 June 1 6 On the Mechanical Conditions of the De- 
 posit of a Submarine Cable. 
 
 1858 July Instructions and Chart for Observations of 
 Mars in right ascension at the Opposi- 
 tion of 1 860 for obtaining the Measure of 
 the Sun's Distance. 
 
 1858 Aug. 20 On the Advantageous Employment of 
 Stereoscopic Photographs for the repre- 
 sentation of Scenery. 
 
 1858 Nov. 6 On the "Draft of Proposed New Statutes 
 for Trinity College, Cambridge." 
 
 1858 Nov. 20 Letter to the Vice-Chancellor of the Uni- 
 versity of Cambridge, offering the Sheep- 
 shanks Endowment. 
 
 1858 Dec. 6 Suggestion of a Proof of the Theorem 
 
 that Every Algebraic Equation has a 
 Root. 
 
 1859 Manual of Astronomy for the Admiralty. 
 1859 Feb. i Letter to Lord Monteagle relating to the 
 
 Standards of Weights and Measures. 
 1859 Feb. 4 Remarks on Mr Cayley's Trigonometrical 
 Theorem, and on Prof. Challis's Proof 
 that Equations have Roots. 
 
 A. B. 
 
 Where published. 
 Camb. Phil. Soc. 
 
 Gr. Obs. 1856, 
 App. 
 
 R. Astr. Soc. 
 (Month. Not.) 
 
 Naut. Mag. 
 
 Phil. Mag. 
 
 R. Astr. Soc. 
 (Special.) 
 
 Photog. Notes. 
 Athenaeum. 
 
 Camb. Phil. Soc. 
 
 Parly. Paper. 
 Phil. Mag. 
 
 2 5 
 
3 86 
 
 APPENDIX. 
 
 Date when read 
 or published. 
 
 Title of Paper. 
 
 1859 Mar. ii On the Movement of the Solar System in 
 Space. .. 
 
 1859 Apr. 8 On the Apparent Pr6jection of Stars upon 
 the Moon's Disc in Occultations. Also 
 Comparison of the Lunar Tables of 
 Burckhardt and Hansen with Observa- 
 tions of the Moon made at the Royal 
 Observatory, Greenwich. 
 
 1859 Apr. 8 On the Apparent Projection of Stars upon 
 the Moon's Disc in Occultations. 
 
 1859 June 4 Report of the Astronomer Royal to the 
 Board of Visitors. 
 
 1859 June 10 Abstract of Maxwell's Paper "On the Sta- 
 bility of the Motion of Saturn's Rings." 
 
 1859 July 8 Corrections of the Elements of the Moon's 
 Orbit, deduced from the Lunar Observa- 
 tions made at the Royal Observatory of 
 Greenwich from 1750 to 1851. 
 
 1859 Sept. 10 On the Invasion of Britain by Julius Caesar. 
 (Answer to Mr Lewin.) 
 
 1859 Nov. 12 On Iron Ships The Royal Charter. (An- 
 swer to Archibald Smith's Remarks.) 
 
 1859 Nov. Circular requesting observations of small 
 Planets. 
 
 1859 Dec. 9 Notice of the approaching Total Eclipse of 
 the Sun of July 18, 1860, and suggestions 
 for observation. 
 
 1859 Dec. 12 Supplement to A Proof of the Theorem 
 
 that Every Algebraic Equation has a 
 Root. 
 
 1860 Jan. 13 Description of the New Equatoreal at the 
 
 Royal Observatory, Greenwich. Also 
 Abstract of an Essay by Gen. T. F. de 
 Schubert on the Figure of the Earth. 
 
 1860 Jan. 28 On the Claudian or Plautian Invasion of 
 Britain. 
 
 1860 Feb. 2 Examination of Navy 2-foot Telescopes at 
 the Royal Observatory, Greenwich, 1860, 
 Jan. 31 to Feb. 2. 
 
 1860 Feb. ii Report on the Instrumental Equipments 
 of the Exchequer Office of Weights and 
 Measures, as regards the means for pre- 
 venting Fraud in the Sale of Gas to the 
 Public; and on the Amendments which 
 
 Where published. 
 
 R. Astr. Soc. 
 
 (Memoirs.) 
 R. Astr. Soc. 
 
 (Month. Not.) 
 
 R. Astr. Soc. 
 (Memoirs.) 
 
 R. Astr. Soc. 
 
 (Month. Not.) 
 R. Astr. Soc. 
 
 (Memoirs.) 
 
 Athenaeum. 
 Athenaeum. 
 
 R. Astr. Soc. 
 (Month. Not.) 
 
 Camb. Phil. Soc. 
 
 R. Astr. Soc. 
 (Month. Not.] 
 
 Athenaeum. 
 
 Ho. of Commons. 
 (Parly. Paper.) 
 
PRINTED PAPERS BY G. B. AIRY. 
 
 387 
 
 Date when read 
 or published. Title of Paper. Where published. 
 
 may be required to the existing Legisla- 
 tion on that subject. 
 1860 Mar. 9 Address on the approaching Solar Eclipse R. Astr. Soc. 
 
 of July 1 8, 1860, &c. (Month. Not.) 
 
 1860 May 10 Correspondence between the Lords Com- Ho. of Commons. 
 
 missioners of Her Majesty's Treasury, (Parly. Paper.) 
 
 &c., and the Astronomer Royal, relating 
 
 to Gas Measurement, and the Sale of 
 
 Gas Act. 
 1860 June 2 Report of the Astronomer Royal to the 
 
 Board of Visitors. And Address to the 
 
 Members of the Board in reference to 
 
 Struve's Geodetic suggestions. 
 1860 June 7 Correspondence regarding the Grant of 
 
 ;iooo to Prof. Hansen for his Lunar 
 
 Tables. 
 1860 Sept. 13 Remarks on a Paper entitled "On the 
 
 Polar Distances of the Greenwich Transit 
 
 Circle, by A. Marth." Addressed to 
 
 the Members of the Board of Visitors. 
 1860 Sept. 22 On Change of Climate, in answer to cer- Athenaeum. 
 
 tain speculations by Sir Henry James. 
 1860 Oct. 20 Circular relating to the distribution of 
 
 Greenwich Observations and other pub- 
 lications of the Royal Observatory. 
 1860 Nov. 9 Account of Observations of the Total Solar R. Astr. Soc. 
 
 Eclipse of 1860, July 18, made at Herefia, (Month. Not.) 
 
 near Miranda de Ebro ; &c. &c. 
 
 1860 Nov. 17 On Change of Climate : further discussion. Athenaeum. 
 1860 Letters on Lighthouses, to the Commission 
 
 on Lighthouses. 
 
 1860 Dec. 14 Note on the translation of a passage in a R. Astr. Soc. 
 
 letter of Hansen's relating to coefficients. (Month. Not.) 
 
 1 86 1 Feb. 9 On the Temperature-correction of Syphon Athenaeum. 
 
 Barometers. 
 1861 March Results of Observations of the Solar Eclipse R. Astr. Soc. 
 
 of 1860 July 18 made at the Royal Obser- (Month. Not.) 
 vatory, Greenwich, for determination of 
 the Errors of the Tabular Elements of 
 the Eclipse. Also Suggestion of a new 
 Astronomical Instrument, for which the 
 name "Orbit-Sweeper 'Ms proposed.. Also 
 Theory of the Regulation of a Clock by 
 Galvanic Currents acting on the Pen- 
 dulum. 25 2 
 
3 88 
 
 APPENDIX. 
 
 Date when read 
 or published. 
 
 Title of Paper. 
 
 1 86 1 June i Report of the Astronomer Royal to the 
 
 Board of Visitors. 
 1861 June 5 On a supposed FaiKire of the Calculus of 
 
 Variations. 
 1861 July Report of a Committee of the R. Soc. on 
 
 the advisability of re-measuring, the 
 
 Indian Arc of Meridian. 
 1 86 1 Sept. 21 Lecture at Manchester on the Great Solar 
 
 Eclipse of July 18, 1860. 
 1 86 1 Sept. 21 The same Lecture. 
 1861 Oct. Examination Paper for the Sheepshanks 
 
 Exhibition. 
 1861 Nov. i Translation of Dr Lament's Paper " On the 
 
 most Advantageous Form of Magnets." 
 1 86 1 Nov. 8 Note on a Letter received from Hansen on 
 
 the Lunar Theory. Also Discussion of 
 
 a Result deduced by Mr D'Abbadie from 
 
 Observations of the Total Solar Eclipse 
 
 of 1860, July 1 8. 
 1861 Nov. 16 Instructions for observing the Total Eclipse 
 
 of the Sun on December 31. 
 1 86 1 Dec. On a Projection by Balance of Errors for 
 
 Maps. 
 
 1861 Dec. 28 On the Circularity of the Sun's Disk. Also 
 
 Table of Comparative Number of Obser- 
 vations of Small Planets. 
 
 1862 Jan. On the Direction of the Joints in the 
 
 Faces of Oblique Arches. 
 1862 Mar. 15 Review of "An Historical Survey of the 
 
 Astronomy of the Ancients" by the Rt 
 
 Hon. Sir G. Cornewall Lewis. 
 1862 Apr. 24 Notes for the Committee on Weights and 
 
 Measures, 1862. 
 1862 May 15 On the Magnetic Properties of Hot-Rolled 
 
 and Cold- Rolled Malleable Iron. 
 1862 June 7 Report of the Astronomer Royal to the 
 
 Board of Visitors. 
 
 1862 June 24 Evidence given before the Select Com- 
 mittee on Weights and Measures. 
 1862 Oct. 4 Biography of G. B. Airy (probably in part 
 
 based upon data supplied by himself). 
 1862 Oct. ii Abstract of Paper "On the Strains in the 
 
 Interior of Beams and Tubular Bridges." 
 1862 Oct. ii Translation of a Letter from Prof. Lamont 
 
 on Dalton's Theory of Vapour, &c. 
 
 Where published. 
 
 Phil. Mag. 
 
 R. Soc. (Proc.) 
 
 Athenaeum. 
 London Review. 
 
 Phil. Mag. 
 
 R. Astr. Soc. 
 (Month. Not.) 
 
 Phil. Mag. 
 
 R. Astr. Soc. 
 (Month. Not.) 
 
 Phil. Mag. 
 Athenaeum. 
 
 Phil. Trans. 
 
 London Review. 
 Athenaeum. 
 Phil. Mag. 
 
PRINTED PAPERS BY G. B. AIRY. 
 
 389 
 
 Date when read 
 or published. 
 
 Title of Paper. 
 
 1862 Nov. 6 On the Strains in the Interior of Beams. 
 
 1862 Nov. Correspondence with Sabine concerning 
 his attack on the Greenwich Magnetic 
 Observations. (Confidentially communi- 
 cated to the Board of Visitors.) 
 
 1862 Nov. 21 Evidence given before the Public Schools 
 Commission. 
 
 1862 Nov. Abstract of M. Auwers's Paper on the 
 proper motion of Procyon, and Note on 
 same. 
 
 1862 Dec. Abstract of Mr Safford's Paper on the 
 
 Proper Motion of Sirius. Also on the 
 Forms of Lenses proper for the Negative 
 Eye-pieces of Telescopes. Also on the 
 measurements of the Earth, and the 
 dimensions of the Solar System. Also 
 on Fringes of Light in Solar Eclipses. 
 
 1863 Jan. Address to the Board of Visitors on a fur- 
 
 ther attack by Sabine on the Greenwich 
 Magnetic Observations (confidential). 
 
 1863 Jan. 9 On the Observations of Saturn made at 
 Pulkowa and Greenwich. 
 
 1863 Feb. 24 Report to the Board of Trade on the 
 Proposed Lines of Railway through 
 Greenwich Park. 
 
 1863 Mar. 2 Determination of the Longitude of Valencia 
 in Ireland by Galvanic Signals in the 
 summer of 1862 (App. III. to the Gr. 
 Astr. Obsns. 1862). 
 
 1863 Mar. 13 On the Movement of the Solar System in 
 Space, deduced from the Proper Motions 
 of 1167 Stars. By Edwin Dunkin (for 
 G. B. A.). 
 
 1863 Mar. 13 On the Visibility of Stars in the Pleiades 
 to the unarmed eye. 
 
 1863 Mar. 21 On Marriage Odes. 
 
 1863 Apr. 9 Further Report as to the Probable Effects 
 of the London, Chatham and Dover 
 Railway on the Royal Observatory in 
 Greenwich Park. 
 
 1863 Apr. 10 Determination of the Sun's Parallax from 
 observations of Mars during the Oppo- 
 sition of 1862. By E. J. Stone (for 
 G. B. A.). Also Remarks on Struve's 
 
 Where published. 
 Phil. Trans. 
 
 R. Astr. Soc. 
 (Month. Not.) 
 
 R. Astr. Soc. 
 (Month. Not.) 
 
 R. Astr. Soc. 
 (Month. Not.) 
 
 R. Astr. Soc. 
 (Memoirs.) 
 
 R. Astr. Soc. 
 
 (Month. Not.) 
 Athenaeum. 
 
 R. Astr. Soc. 
 (Month. Not.) 
 
390 
 
 APPENDIX. 
 
 Date when read 
 or published. 
 
 Title of Paper. 
 
 Where published. 
 
 account of a Local deviation in the di- 
 rection of Gravity, near Moscow. Also 
 an Account of ah apparatus for the 
 observation of the spectra of stars, and 
 results obtained. 
 
 1863 Apr. 23 On the Diurnal Inequalities of Terrestrial 
 Magnetism, as deduced from observa- 
 tions made at the Royal Observatory, 
 Greenwich, from 1841 to 1857. 
 
 1863 May 8 On the Discordance between the Results 
 for Zenith-Distances obtained by Direct 
 Observation, and those obtained by 
 Observation by Reflection from the Sur- 
 face of Quicksilver. 
 1863 June 6 Report of the Astronomer Royal to the 
 
 Board of Visitors. 
 
 1863 July 2 On the Amount of Light given by the 
 Moon at the greatest stage in the Ex- 
 centrically-total Eclipse, 1863, June i. 
 1863 Aug. Plan of the Buildings and Grounds of the 
 Royal Observatory, Greenwich, with 
 Explanation and History. 
 
 1863 Sept. 5 On the origin of the apparent luminous 
 band which, in partial eclipses of the 
 Sun, has been seen to surround the 
 visible portion of the Moon's limb. 
 
 fiS63 Sept. 5 On the Invasions of Britain by Julius 
 \i863 Oct. 3 Caesar. 
 
 1863 Oct. 17 The Earthquake as observed from Green- 
 wich. 
 
 1863 Nov. On the Numerical Expression of the De- 
 structive Energy in the Explosions of 
 Steam- Boilers, &c. 
 
 1863 Nov. 13 Convention arranged between M. LeVerrier 
 and the Astronomer Royal for meridi- 
 onal observations of the small Planets, 
 &c. 
 
 1863 Nov. 13 Translation of Hansen's Paper "Calcula- 
 tion of the Sun's Parallax from the 
 Lunar Theory," with Notes by G. B. A. 
 1863 Dec. 17 First Analysis of 177 Magnetic Storms, 
 registered by the Magnetic Instruments 
 in the Royal Observatory, Greenwich, 
 from 1841 to 1857. 
 
 Phil. Trans. 
 
 R. Astr. Soc. 
 (Memoirs.) 
 
 R. Astr. Soc. 
 (Month. Not.) 
 
 R. Astr. Soc. 
 (Month. Not.) 
 
 Athenaeum. 
 Athenaeum. 
 Phil. Mag. 
 
 R. Astr. Soc. 
 (Month. Not.) 
 
 R. Astr. Soc. 
 (Month. Not.) 
 
 Phil. Trans. 
 
PRINTED PAPERS BY G. B. AIRY. 
 
 391 
 
 Date when read 
 or published. 
 
 Title of Paper. 
 
 1864 Jan. 8 Pontecoulant's Paper " Sur le Coefficiant 
 de 1'Equation Parallactique deduit de la 
 Theorie," with Notes by G. B. A. 
 
 1864 Jan. 26 Remarks on Redman's Paper on the East 
 Coast (Chesil Bank, &c.). 
 
 1864 Mar. 10 Note on a Passage in Capt. Jacob's 
 " Measures of Jupiter," &c. 
 
 1864 Mar. ii Notes for the Committee on Weights and 
 Measures, 1862. 
 
 1864 Mar. 17 On a Method of Slewing a Ship without 
 the aid of the Rudder. 
 
 1864 Apr. 5 Comparison of the Chinese Record of Solar 
 Eclipses in the Chun Tsew with the 
 Computations of Modern Theory. 
 
 1864 June 4 Report of the Astronomer Royal to the 
 Board of Visitors. 
 
 1864 June 10 On the Transit of Venus, 1882, Dec. 6. 
 
 1864 June 10 On the bright band bordering the Moon's 
 Limb in Photographs of Eclipses. 
 
 1864 Notes on Methods of Reduction appli- 
 
 cable to the Indian Survey. 
 
 1864 Sept. 3 A Visit to the Corryvreckan. 
 
 1864 Sept. 29 Examination Paper for the Sheepshanks 
 
 Scholarship. 
 
 1865 Jan. 13 Comparison of the Transit-Instrument in 
 
 its ordinary or reversible form with the 
 Transit-Instrument in its non-reversi- 
 ble form, as adopted at Greenwich, the 
 Cape of Good Hope, and other Observa- 
 tories. 
 
 1865 Mar. 9 Syllabus of a course of three Lectures on 
 " Magnetical Errors, &c., with special 
 reference to Iron Ships and their Com- 
 passes," delivered at the South Kensing- 
 ton Museum. 
 
 1865 Apr. i Remarks on Mr Ellis's Lecture on the 
 Greenwich System of Time Signals. 
 
 1865 Apr. i Free Translation of some lines of Virgil, 
 " Cithara crinitus lopas," &c. 
 
 1865 June 3 Report of the Astronomer Royal to the 
 Board of Visitors. 
 
 1865 June 17 Note on my Recommendation (in 1839) 
 of Government Superintendence of the 
 
 Where published. 
 
 R. Astr. Soc. 
 (Month. Not.) 
 
 Inst. C. E. 
 
 (Minutes.) 
 R. Astr. Soc. 
 
 (Month. Not.) 
 Ho. of Comm. 
 
 (Parly. Paper.) 
 Inst. Nav. Arch. 
 
 R. Astr. Soc. 
 (Month. Not.) 
 
 R. Astr. Soc. 
 
 (Month. Not) 
 R. Astr. Soc. 
 
 (Month. Not.) 
 
 Athenaeum. 
 
 R. Astr. Soc. 
 
 (Month. Not.) 
 
 Horolog. Journ. 
 Athenaeum. 
 
 Athenaeum. 
 
392 
 
 APPENDIX. 
 
 Date when read 
 or published. Title of Paper. Where published. 
 
 Compasses of Iron Ships. Also Note on 
 the birthplace of Thomas Clarkson. 
 
 1865 July On Hemiopsy. Phil. Mag. 
 
 1865 Aug. 22 On the Value of the Moon's Semidiameter R. Astr. Soc. 
 
 as obtained by the Investigations of (Month. Not.) 
 Hugh Breen, Esq., from Occultations 
 observed at Cambridge and Greenwich. 
 
 1865 Sept. 16 On "The Land of Goshen" Reply to "A Athenaeum. 
 Suffolk Incumbent." 
 
 1865 Oct. 21 Address of the Astronomer Royal to the in- 
 dividual members of the Board of Visi- 
 tors. (On improved Collimators.) 
 
 1865 Oct. 23 Note on an Error of Expression in two pre- R. Astr. Soc. 
 
 vious Memoirs. Also Description and (Month. Not.) 
 
 History of a Quadrant made by Abraham 
 
 Sharp. 
 
 1865 Nov. ii On the Possible Derivation of the National Athenaeum. 
 Name "Welsh." 
 
 1865 Essays on the Invasion of Britain by Julius Private. 
 
 Caesar; The Invasion of Britain by Plau- 
 tius, and by Claudius Caesar ; The Early 
 Military Policy of the Romans in Britain; 
 The Battle of Hastings. (With corr.) 
 
 1866 Mar. 10 On "The Compass in Iron Ships." Objec- Athenaeum. 
 
 tions to passages in a Lecture by Archi- 
 bald Smith. 
 
 1866 Apr. 13 On the Supposed Possible Effect of Fric- R. Astr. Soc. 
 
 tion in the Tides, in influencing the Ap- (Month. Not.) 
 parent Acceleration of the Moon's Mean 
 Motion in Longitude. Also on a Method 
 of Computing Interpolations to the 
 Second Order without Changes of Alge- 
 braic Sign. 
 
 1866 June 2 Report of the Astronomer Royal to the 
 Board of Visitors. 
 
 1866 July 17 Papers relating to Time Signals on the Ho. of Comm. 
 
 Start Point. (Parly. Paper.) 
 
 1866 Sept. i On the Campaign of Aulus Plautius in Athenaeum. 
 Britain. (Reply to Dr Guest.) 
 
 1866 Nov. 19 On the Continued Change in an Eye af- Camb. Phil. Soc. 
 fected with a peculiar malformation. 
 
 1866 Dec. On the Simultaneous Disappearance of R. Astr. Soc. 
 
 Jupiter's Satellites in the year 1867. Also (Month. Not.) 
 Inference from the observed Movement 
 
PRINTED PAPERS BY G. B. AIRY. 
 
 393 
 
 Date when read 
 or published. 
 
 Title of Paper. 
 
 Where published. 
 
 of the Meteors in the appearance of 1866, 
 
 Nov. 13-14. 
 1867 Jan. i Memorandum for the consideration of the 
 
 Commission on Standards. (Policy of 
 
 introducing Metrical Standards.) 
 1867 Jan. 12 On Decimal Weights and Measures. 
 1867 Feb. 19 On the use of the Suspension Bridge with 
 
 Stiffened Roadway for Railway and other 
 
 Bridges of Great Span. 
 1867 Mar. 21 Computation of the Lengths of the Waves 
 
 of Light corresponding to the Lines in 
 
 the Dispersion Spectrum measured by 
 
 Kirchhoff. 
 1867 Mar. Corresponding Numbers of Elevation in 
 
 English Feet, and of Readings of Ane- 
 roid or Corrected Barometer in English 
 
 Inches. 
 1867 Apr. 1 6 Remarks on Sir W. Denison's Paper on 
 
 "The Suez Canal." 
 1867 May 3 Statement of the History and Position of 
 
 the Blue-coat Girls' School, Greenwich. 
 1867 June i Report of the Astronomer Royal to the 
 
 Board of Visitors. 
 1867 June 14 On Certain Appearances of the Telescopic 
 
 Images of Stars described by the Rev. 
 
 W. R. Dawes. 
 
 1867 Dec. 13 Note on the Total Solar Eclipse of 1868, 
 
 Aug. 17-18. 
 
 1868 Biography of G. B. Airy. (Probably cor- 
 
 rected by himself.) 
 
 1868 Jan. 4 Biography (with portrait) of G. B. Airy. 
 (Probably corrected by himself.) 
 
 1868 Feb. 6 Comparison of Magnetic Disturbances re- 
 corded by the Self-registering Magneto- 
 meters at the Royal Observatory, Green- 
 wich, with Magnetic Disturbances de- 
 duced from the corresponding Terrestrial 
 Galvanic Currents recorded by the Self- 
 registering Galvanometers of the Royal 
 Observatory. 
 
 1868 Mar. 13 Address of the Astronomer Royal to the 
 Individual Members of the Board of Visi- 
 tors. (Number of Copies of Observa- 
 tions.) 
 
 Athenaeum. 
 Inst. C. E. 
 (Minutes.) 
 
 Phil. Trans. 
 
 R. Obs. (Also 
 Meteor. Soc. 
 Apr. 17, 1867.) 
 
 Inst. C. E. 
 
 (Minutes.) 
 Private. 
 
 R. Astr. Soc. 
 (Month. Not.) 
 
 R. Astr. Soc. 
 (Month. Not.) 
 
 111. Lond. News. 
 Phil. Trans. 
 
394 
 
 APPENDIX. 
 
 Date when read 
 or published. 
 
 Title of Paper. 
 
 Where published. 
 
 1868 June 6 Report of the Astronomer Royal to the 
 
 Board of Visitors. 
 1868 July 24 First Report of the "Commissioners ap- Parly. Paper. 
 
 pointed to enquire into The Condition of 
 
 the Exchequer Standards. 
 
 1868 Sept. 19 The Inundation at Visp. j. Athenaeum. 
 
 1868 Nov. 9 On the Factorial Resolution of the Trino- Camb. Phil. Soc. 
 
 mial x n - 2 cos #. a. + -. 
 
 1868 Dec. 10 On the Diurnal and Annual Inequalities Phil. Trans. 
 
 of Terrestrial Magnetism, as deduced 
 
 from Observations made at the Royal 
 
 Observatory from 1858 to 1863, &c. 
 1868 Dec. ii On the Preparatory Arrangements for the R. Astr. Soc. 
 
 Observation of The Transits of Venus (Month. Not.) 
 
 1874 and 1882. 
 
 1868 Dec. 12 On the Migrations of the Welsh Nations. Athenaeum. 
 
 1869 Mar. 8 Memorandum by the Chairman (on the 
 
 use of the Troy Weight) for the con- 
 sideration of the Members of the Stan- 
 dards Commission. 
 1869 Apr. 3 Second Report of the Commissioners ap- Parly. Paper. 
 
 pointed to enquire into the condition of 
 
 the Exchequer (now Board of Trade) 
 
 Standards. The Metric System. 
 1869 April Syllabus of Lectures on Magnetism to be 
 
 delivered in the University of Cambridge. 
 1869 Apr. 27 Remarks on Shelford's Paper "On the Inst. C. E. 
 
 Outfall of the River Humber." (Minutes.) 
 
 1869 June i Memorandum for the consideration of the 
 
 Standards Commission, on the state of 
 
 the Question now before them regarding 
 
 the suggested Abolition of Troy Weight. 
 1869 June 5 Report of the Astronomer Royal to the 
 
 Board of Visitors. 
 
 1869 Supplementary Memorandum by the Astro- 
 
 nomer Royal on the proposed Abolition 
 
 of Troy Weight. 
 1869 July 6 Correspondence between the Treasury, the Ho. of Comm. 
 
 Admiralty, and the Astronomer Royal, (Parly. Paper.) 
 
 respecting the arrangements to be made 
 
 for Observing the Transits of Venus, 
 
 which will take place in the years 1874 
 
 and 1882. 
 
PRINTED PAPERS BY G. B. AIRY. 
 
 395 
 
 Date when read 
 or published. Title of Paper. Where published. 
 
 1869 Aug. 7 Note on Atmospheric Chromatic Disper- R. Astr. Soc. 
 
 sion as affecting Telescopic Observation, (Month. Not.) 
 and on the Mode of Correcting it. 
 
 1869 Oct. 19 Description of the Great Equatoreal of the 
 
 Royal Observatory, Greenwich. Green- 
 wich Observations, 1868. App. 
 
 1870 Feb. 3 Note on an Extension of the Comparison Phil. Trans. 
 
 of Magnetic Disturbances with Magnetic 
 Effects inferred from observed Terres- 
 trial Galvanic Currents ; &c. &c. 
 
 1870 Apr. 8 On the question of a Royal Commission for Journ. Soc. Arts. 
 Science. 
 
 1870 May 2 Letters to the First Lord of the Admiralty 
 enclosing Application of the Assistants 
 for an increase of Salaries. 
 
 1870 May 13 On Decimal and Metrical Systems. Journ. Soc. Arts. 
 
 1870 June 4 Report of the Astronomer Royal to the 
 Board of Visitors. 
 
 1870 Aug. 27 On the meaning of the word " Whippultree." Athenaeum. 
 
 1870 Oct. 22 On the Locality of " Paradise." Athenauim. 
 
 1870 Nov. 12 On the Locality of the Roman Gesoriacum. Athenaeum. 
 
 1870 Nov. 30 Recommendation of Prof. Miller for a R. Soc. (Proc.) 
 Royal Medal of the Royal Society. 
 (Quoted by the President.) 
 
 1870 Revised Edition of " Astronomy." Man. Naut. Sci. 
 
 1871 Jan. 21 The Burial of Sir John Moore. Athenaeum. 
 1871 Mar. 14 Letter to the Hydrographer of the Admiralty 
 
 on the qualifications and claims of the 
 
 Assistants of the Royal Observatory. 
 1871 Apr. 5 Remarks on the Determination of a Ship's R. Soc. (Proc.) 
 
 Place at Sea. 
 1871 May 2 Remarks on Samuelson's Paper " Descrip- Inst. C. E. 
 
 tion of two Blast Furnaces," &c. (Minutes.) 
 
 1871 May 3 Note on Barometric Compensation of the Phil. Mag. 
 
 Pendulum. 
 1871 June 3 Report of the Astronomer Royal to the 
 
 Board of Visitors. 
 1871 June 9 Remarks on Mr Abbott's observations on R. Astr. Soc. 
 
 77 Argus. Also on A. S. Herschel's and (Month. Not.) 
 
 J. Herschel's Mechanism for measuring 
 
 Time automatically in taking Transits. 
 1871 Erratum in Results of Greenwich Obser- R. Astr. Soc. 
 
 vations of the Solar Eclipse of 1860, (Month. Not.) 
 
 July 1 8. Also Observations of the Solar 
 
396 
 
 APPENDIX. 
 
 Date when read 
 or published. Title of Paper. Where published. 
 
 Eclipse of 1870, Dec. 21-22, made at the 
 Royal Observatory, Qreenwich. 
 
 1871 Aug. Investigation of the LELW of the Progress of Phil. Mag. 
 Accuracy in the usual process for Form- 
 ing a Plane Surface. 
 
 1871 Nov. 1 6 Corrections to the Computed Lengths of Phil. Trans. 
 Waves of Light for Kirchhoff 's Spectral 
 Lines. 
 
 1871 On a supposed alteration in the amount of R. Soc. (Proc.) 
 
 Astronomical Aberration of Light, pro- 
 duced by the passage of the Light 
 through a considerable thickness of Re- 
 fracting Medium. 
 
 1871 Nov. 29 Biography of G. B. Airy. (Probably cor- Daily Telegraph, 
 rected by himself.) 
 
 1871 Dec. 8 Note on a special point in the determina- R. Astr. Soc. 
 
 tion of the Elements of the Moon's Orbit (Month. Not.) 
 
 from Meridional Observations of the 
 
 Moon. 
 
 1871 Dec. 26 Proposed devotion of an Observatory to R. Astr. Soc. 
 
 observation of the phenomena of Jupiter's (Month. Not.) 
 Satellites. 
 
 1872 Jan. Address to the Council of the Royal Society 
 
 on the propriety of continuing the Grant 
 to the Kew Observatory for meteorologi- 
 cal observations. 
 
 1872 Feb. 8 Experiments on the Directive Power of Phil. Trans, 
 large Steel Magnets, of Bars of magnet- 
 ized Soft Iron, and of Galvanic Coils, in 
 their Action on external small Magnets 
 with Appendix by James Stuart. 
 
 1872 Feb. 12 Further Observations on the state of an Camb. Phil. Soc. 
 Eye affected with a peculiar malforma- 
 tion. 
 
 1872 Mar. 20 Notes on Scientific Education, submitted 
 to the Royal Commission on Scientific 
 Instruction and the Advancement of 
 Science. 
 
 1872 May 9 On a Supposed Periodicity in the Ele- R. Soc. (Proc.) 
 ments of Terrestrial Magnetism, with a 
 period of 26^ days. 
 
 1872 Nov. 30 Address (as President) delivered at the 
 Anniversary Meeting of the Royal So- 
 ciety. 
 
PRINTED PAPERS BY G. B. AIRY. 
 
 397 
 
 Date when read 
 or published. 
 
 Title of Paper. 
 
 1872 Dec. 19 Magnetical Observations in the Britannia 
 
 and Conway Tubular Iron Bridges. 
 
 1873 Feb. 25 Remarks on Mr Thornton's Paper on "The 
 
 State Railways of India" chiefly in refe- 
 rence to the proposed break of gauge. 
 
 1873 Mar. 12 Note on the want of Observations of 
 Eclipses of Jupiter's First Satellite from 
 1868 to 1872. 
 
 1873 Mar. 14 Letter to the Secretary of the Admiralty 
 on certain Articles which had appeared 
 in the Public Newspapers in regard to 
 the approaching Transit of Venus. 
 
 1873 Additional Note to the Paper on a sup- 
 
 posed Alteration in the Amount of Astro- 
 nomical Aberration of Light produced 
 by the passage of the Light through a 
 considerable thickness of Refracting 
 Medium. 
 
 1873 Apr. 10 List of Candidates for election into the 
 Royal Society classified. 
 
 1873 On tne Topography of the " Lady of the 
 
 Lake." 
 
 1873 June 7 Report of the Astronomer Royal to the 
 Board of Visitors. 
 
 1873 Nov. 14 On the rejection, in the Lunar Theory, of 
 the term of Longitude depending for 
 argument on eight times the mean longi- 
 tude of Venus minus thirteen times the 
 mean longitude of the Earth, introduced 
 by Prof. Hansen ; &c. 
 
 1873 Dec. i Address (as President) delivered at the Anni- 
 
 versary Meeting of the Royal Society. 
 
 1874 Jan. On a Proposed New Method of treating 
 
 the Lunar Theory. 
 1874 May 4 British Expeditions for the Observation of 
 
 the Transit of Venus, 1874, December 8. 
 
 Instructions to Observers. 
 1874 June 6 Report of the Astronomer Royal to the 
 
 Board of Visitors. 
 1874 Aug. 6 Regulations of the Royal Observatory, 
 
 Greenwich. Appendix to the Greenwich 
 
 Observations, 1873. 
 1874 Oct. 3 Science and Art. The Moon as carved on 
 
 Lee church. 
 
 Where published. 
 Phil. Trans. 
 
 Inst. C. E. 
 
 (Minutes.) 
 
 R. Astr. Soc. 
 (Month. Not.) 
 
 R. Astr. Soc. 
 (Month. Not.) 
 
 R. Soc. (Proc.) 
 
 Private. 
 
 R. Astr. Soc. 
 (Month. Not.) 
 
 R. Astr. Soc. 
 (Month. Not.) 
 
 Athenaeum. 
 
398 
 
 APPENDIX. 
 
 Date when read 
 or published. 
 
 Title of Paper. 
 
 1874 Nov. 13 Preparations for the Observation of the 
 Transit of Venus 1874, December 8-9. 
 
 1874 Nov. 17 Remarks on the Paj$er "On the Nagpur 
 Waterworks." 
 
 1874 Dec. Telegrams relating to the Observations of 
 
 the Transit of Venus 1874, Dec. 9. ^ 
 
 1875 Feb. 2 Remarks on Mr Prestwich's Paper on the 
 
 Origin of the Chesil Bank. 
 1875 Feb - 2 5 Letter to the Rev. N. M. Ferrers, on the 
 
 subject of the Smith's Prizes. 
 1875 Mar. 12 On the Method to be used in Reducing 
 
 the Observations of the Transit of Venus 
 
 1874, Dec. 8. 
 
 1875 Mar. Report on the Progress made in the Cal- 
 culations for a New Method of treating 
 
 the Lunar Theory. 
 1875 June 5 Report of the Astronomer Royal to the 
 
 Board of Visitors. 
 1875 J une 7 Apparatus for Final Adjustment of the 
 
 Thermal Compensation of Chronometers, 
 
 by the Astronomer Royal. 
 
 1875 Nov. Chart of the Apparent Path of Mars, 1877, 
 
 with neighbouring Stars. Also Spectro- 
 scopic Observations made at the Royal 
 Observatory, Greenwich. Also Obser- 
 vations of the Solar Eclipse of 1875, 
 September 28-29, made at the Royal 
 Observatory, Greenwich. 
 
 1876 Jan. Report by the Astronomer Royal on the 
 
 present state of the Calculations in his 
 New Lunar Theory. 
 
 1876 Jan. 27 Note on a point in the life of Sir William 
 Herschel. 
 
 1876 Mar. 15 Evidence given before the Government 
 Committee on the Meteorological Com- 
 mittee. 
 
 1876 May 20 On Toasting at Public Dinners. 
 
 1876 June 3 Report of the Astronomer Royal to the 
 Board of Visitors. 
 
 1876 Aug. 7 On a Speech attributed to Nelson. 
 
 1876 Dec. Spectroscopic Results for the Rotation of 
 
 Jupiter and of the Sun, obtained at the 
 Royal Observatory, Greenwich. 
 
 1877 Jan. Stars to be compared in R.A. with Mars, 
 
 Where published. 
 
 R. Astr. Soc. 
 
 (Month. Not.) 
 Inst. C. E. 
 
 (Minutes.) 
 R. Astr. Soc. 
 
 (Month. Not.) 
 Inst. C. E. 
 
 (Minutes.) 
 
 R. Astr. Soc. 
 (Month. Not.) 
 
 R. Astr. Soc. 
 (Month. Not.) 
 
 Horolog. Journ. 
 
 R. Astr. Soc. 
 (Month. Not.) 
 
 R. Astr. Soc. 
 (Month. Not.) 
 
 Athenaeum. 
 
 Public Opinion. 
 
 Athenaeum. 
 R. Astr. Soc. 
 (Month. Not.) 
 
 R. Astr. Soc. 
 
PRINTED PAPERS BY G. B. AIRY. 
 
 399 
 
 Date when read 
 or published. Title of Paper. Where published. 
 
 1877, for Determination of the Parallax (Month. Not) 
 of Mars. 
 1877 Mar. Note by the Astronomer Royal on the R. Astr. Soc. 
 
 Numerical Lunar Theory. Also Remarks (Month. Not.) 
 on Le Verrier's intra-Mercurial Planet. 
 Also on Observations for the Parallax of 
 Mars. 
 1877 Mar. 27 Remarks on a Paper on "The River Inst. C. E. 
 
 Thames." (Minutes.) 
 
 1877 Apr. On observing for Le Verrier's intra-Mer- R. Astr. Soc. 
 
 curial Planet. Also on the Parallax of (Month. Not.) 
 Mars, and Mr Gill's proposed expedition. 
 1877 May On the vulgar notion that the Sun or Moon The Observatory 
 
 is smallest when overhead. (No. 2). 
 
 1877 Ju ne 2 Report of the Astronomer Royal to the 
 
 Board of Visitors. 
 
 1877 July 16 Report on the Telescopic Observations of Ho. of Commons 
 the Transit of Venus 1874, made in the Parly. Paper. 
 Expedition of the British Government, 
 and on the Conclusion derived from 
 those Observations. 
 1877 Sept. 13 On Spurious Discs of Stars produced by The Observatory 
 
 oval object-glasses. (No. 7). 
 
 1877 Sept. 24 Obituary Notice of the work of Le Verrier Daily News. 
 
 died Sept. 23, 1877. 
 
 1877 Nov. 20 On the Value of the Mean Solar Parallax The Observatory 
 &c. from the British telescopic Obscrva- (No. 8). 
 tions of the Transit of Venus 1874. 
 Also Remarks on Prof. Adams's Lunar 
 Theory. 
 1877 Nov. On the Inferences for the Value of Mean R. Astr. Soc. 
 
 Solar Parallax &c. from the Telescopic (Month. Not.) 
 Observations of the Transit of Venus 
 1874, which were made in the British 
 Expedition for the Observation of that 
 Transit. 
 
 1877 Numerical Lunar Theory: Appendix to 
 
 Greenwich Astronomical Observations 
 1875. 
 
 1877 Dec. 6 On the Tides at Malta. Phil. Trans. 
 
 1878 Correspondence with Le Verrier on his The Observatory 
 
 Planetary Tables in 1876. (No. 10). 
 
 1878 On the Proposal of the French Committee The Observatory 
 
 to erect a Statue to Le .Verrier. Also (No. 13). 
 
400 
 
 APPENDIX. 
 
 Date when read 
 or published. Title of Paper. Where published. 
 
 on the Observation of the approaching 
 
 Transit -of Mercury. 
 
 1878 Mar. ii On the Correction of- the Compass in Iron Phil. Mag. 
 
 Ships without use of a Fixed Mark. 
 
 1878 Mar. 30 On the Standards of Length in the Guild- The Times. 
 
 hall, London. 
 
 1878 Apr. 27 Report of Lecture on "The probable con- W. Cumberland 
 
 dition of the Interior of the Earth." Times. 
 
 On the probable condition of the Interior Trans, of the 
 
 of the Earth Revised Edition of above Cumberland 
 
 Lecture. Assoc., &c. 
 
 1878 June i Discussion of the Observations of the The Observatory 
 
 Transit of Mercury on May 6. (No. 14). 
 
 1878 Abstract of Lecture delivered at Cocker- The Observatory 
 
 mouth on " The Interior of the Earth." (No. 14). 
 1878 June i Report of the Astronomer Royal to the 
 
 Board of Visitors. 
 
 1878 July i Remarks on the measurement of the pho- The Observatory 
 
 tographs taken in the Transit of Venus (No. 15). 
 
 Observations. 
 
 1878 July 13 On the Variable Star R. Scuti: distortion The Observatory 
 
 in the Photo-heliograph. (No. 16). 
 
 1878 Remarks on Mr Gill's Heliometric Obser- The Observatory 
 
 vations of Mars. (No. 20). 
 
 1878 Dec. Note on a Determination of the Mass of R. Astr. Soc. 
 
 Mars, and reference to his own deter- (Month. Not.) 
 mination in 1828. Also Note on the Con- 
 junction of Mars and Saturn, 1879, June 30. 
 
 1879 Jan. i On the remarkable conjunction of the The Observatory 
 
 Planets Mars and Saturn which will (No. 21). 
 
 occur on 1879, J une 3- 
 
 1879 Feb. 15 On the names " Cabul" and " Malek." Athenaeum. 
 
 1879 Feb. 25 On Faggot Votes in Cornwall in 1828. Athenaeum. 
 
 1879 Mar. 13 Letter on the Examination Papers for the 
 
 Smith's Prizes. 
 
 1879 Apr. 7 Drafts of Resolutions proposed concern- 
 ing Sadler's Notes on the late Admiral 
 
 Smyth's " Cycle of Celestial Objects." 
 1879 June i Letter to Le Verrier, dated 1875, Feb. 5, in The Observatory 
 
 support of the Method of Least Squares. (No. 26). 
 1879 J une l Remarks in debate on Sadler's "Notes" The Observatory 
 
 above-mentioned. (No. 26). 
 
 1879 June 7 Report of the Astronomer Royal to the 
 
 Board of Visitors. 
 
PRINTED PAPERS BY G. B. AIRY. 
 
 4OI 
 
 Date when read 
 or published. 
 
 Title of Paper. 
 
 1879 J u ty 2 9 Index to the Records of occasional Obser- 
 vations and Calculations made at the 
 Royal Observatory, Greenwich, and to 
 other miscellaneous Papers connected 
 with that Institution. 
 
 1879 Biography of G. B. Airy (perhaps corrected 
 
 by himself) in French, published at 
 Geneva. 
 
 1879 Sept. On the Construction and Use of a Scale 
 
 for Gauging Cylindrical Measures of 
 Capacity. 
 
 1880 On the Theoretical Value of the Accelera- 
 
 tion of the Moon's Mean Motion. 
 
 1880 On the Secular Acceleration of the Moon 
 
 additional note. 
 
 1880 Apr. 27 Memoranda for the Commission appointed 
 to consider the Tay Bridge casualty. 
 
 1880 Apr. On the Theoretical Value of the Accele- 
 ration of the Moon's Mean Motion in 
 Longitude produced by the Change of 
 Eccentricity of the Earth's Orbit. 
 
 1880 May On the Preparations to be made for Obser- 
 vation of the Transit of Venus 1882, 
 Dec. 6. 
 
 1880 On the present Proximity of Jupiter to the 
 
 Earth, and on the Intervals of Recur- 
 rence of the same Phenomena. 
 
 1880 June 5 Report of the Astronomer Royal to the 
 Board of Visitors. 
 
 1880 Sept. 4 On the e muet in French. 
 
 1880 Sept. 4 Excursions in the Keswick District. 
 
 1880 Dec. i Description of Flamsteed's Equatoreal 
 Sextant, and Remarks on Graham. 
 
 1880 Addition to a Paper entitled "On the 
 
 Theoretical Value of the Moon's Mean 
 Motion in Longitude," &c. 
 
 1 88 1 Mar. Effect on the Moon's Movement in Lati- 
 
 tude, produced by the slow change of 
 
 Position of the Plane of the Ecliptic. 
 1 88 1 June 4 Report of the Astronomer Royal to the 
 
 Board of Visitors. 
 1 88 1 Logarithms of the Values of all Vulgar 
 
 Fractions with Numerator and Denomi- 
 
 A. B. 
 
 Where published. 
 
 R. Astr. Soc. 
 
 (Month. Not. 
 supplementary.) 
 
 Phil. Mag. 
 
 The Observatory 
 
 (No. 37). 
 The Observatory 
 
 (No. 37). 
 
 R. Astr. Soc. 
 (Month. Not.) 
 
 R. Astr. Soc. 
 (Month. Not.) 
 
 The Observatory 
 (No. 42). 
 
 Athenaeum. 
 Keswick 
 
 Guardian. 
 The Observatory 
 
 (No. 44). 
 R. Astr. Soc. 
 
 (Month. Not. 
 supplementary. ) 
 R. Astr. Soc. 
 
 (Month. Not.) 
 
 Inst. C. E. 
 (Minutes.) 
 
 26 
 
402 
 
 APPENDIX. 
 
 Date when read 
 or published. 
 
 Title of Paper. 
 
 Where published. 
 
 nator not exceeding 100 : arranged in 
 order of magnitude. 
 
 1 88 1 July 6 A New Method of Clearing the Lunar Dis- 
 tance. Admiralty. 
 
 1 88 1 Aug. 4 On a Systematic Interruption in the order Phil. Mag. 
 
 of numerical values of Vulgar Fractions, 
 when arranged in a series of consecutive 
 magnitudes. 
 
 1882 Sept. 15 Monthly Means of the Highest and R. Soc. (Proc. 
 
 Lowest Diurnal Temperatures of the 
 Water of the Thames, and Comparison 
 with the corresponding Temperatures of 
 the Air at the Royal Observatory, Green- 
 wich. 
 1882 Oct. 19 On the Proposed Forth Bridge. 
 
 1882 Dec. 7 On the Proposed Forth Bridge. 
 
 1883 Jan. 21 On the Ossianic Poems. 
 
 1883 Mar. 12 On the proposed Braithwaite and Butter- 
 mere Railway. 
 
 1883 Apr. 28 Memorandum on the progress of the Nu- 
 merical Lunar Theory, addressed to the 
 Board of Visitors of the Royal Observa- 
 tory, Greenwich. 
 
 1883 Letter on The Apparent Inequality in the 
 
 Mean Motion of the Moon. 
 
 1883 Aug. 1 8 On a Singular Morning Dream. 
 
 1883 Sept. 10 Power of organization of the common 
 mouse. 
 
 1883 Nov. 17 On Chepstow Railway Bridge, with general 
 
 remarks suggested by that Structure. 
 
 1884 Mar. 8 On the Erroneous Usage of the term " arte- 
 
 rial drainage." 
 
 1884 On the Comparison of Reversible and Non- 
 
 reversible Transit Instruments. 
 
 1884 Nov. 10 On an obscure passage in the Koran. 
 
 1885 May 28 An Incident in the History of Trinity Col- 
 
 lege, Cambridge. 
 
 1885 June 8 Incident No. 2 in the History of Trinity 
 College, Cambridge. 
 
 1885 Nov. 26 Results deduced from the Measure of Ter- 
 restrial Magnetic Force in the Horizontal 
 Plane, at the Royal Observatory, Green- 
 wich, from 1841 to 1876. 
 
 Nature. 
 Nature. 
 Athenaeum. 
 
 rDaily News. 
 J Times. 
 
 I Standard. 
 
 The Observatory 
 
 (No. 74)- 
 Nature. 
 Nature. 
 
 Nature. 
 Athenaeum. 
 
 The Observatory 
 
 (No. 85). 
 Nature. (?) 
 Athenaeum. 
 
 Athenaeum. 
 Phil. Trans. 
 
PRINTED PAPERS BY G. B. AIRY. 
 
 403 
 
 Date when read 
 or published. 
 
 1886 Apr. 6 
 
 Where published. 
 Nature. 
 
 Title of Paper. 
 
 Integer Members of the First Centenary 
 
 satisfying the Equation A* = B* + C 2 . 
 1887 Feb. 12 On the earlier Tripos of the University of Nature. (?) 
 
 Cambridge : in MSS. 
 
 1887 Apr. 14 On the Establishment of the Roman Domi- 
 nion in South-East Britain. 
 
 1887 July 23 On a special Algebraic function, and its 
 application to the solution of some Equa- 
 tions : in MSS. 
 
 Nature. 
 
 Camb. Phil Soc. 
 
 262 
 
BOOKS WRITTEN BY G. B. AIRY. 
 
 Mathematical Tracts on Physical Astronomy, the Figure of the Earth, 
 Precession and Nutation, and The Calculus of Variations. This 
 was published in 1826. In a 2nd Edition published in 1831 
 the Undulatory Theory of Optics was added to the above list. 
 Four Editions of this work have been published, the last in 1858. 
 The Undulatory Theory of Optics was published separately in 
 1877. 
 
 Gravitation : an Elementary Explanation of the Principal Perturbations 
 in the Solar System. Written for the Penny Cyclopaedia, and 
 published previously as a book in 1834. There was a 2nd Edition 
 in 1884. 
 
 Trigonometry. This was written for the Encyclopaedia Metropolitana 
 about 1825, and was published as a separate book in 1855 un der 
 the Title of " A Treatise on Trigonometry." 
 
 Six Lectures on Astronomy delivered at the meetings of the friends of 
 the Ipswich Museum at the Temperance Hall, Ipswich, in the 
 month of March 1848. These Lectures under the above Title, 
 and that of " Popular Astronomy, a series of Lectures," have run 
 through twelve editions. 
 
 On the Algebraical and Numerical Theory of Errors of Observations 
 and the Combination of Observations, ist Edition in 1861, 2nd 
 in 1875, 3rd in 1879. 
 
 Essays on the Invasion of Britain by Julius Caesar; The Invasion of 
 Britain by Plautius, and by Claudius Caesar; The Early Military 
 Policy of the Romans in Britain; The Battle of Hastings; with 
 Correspondence. Collected and printed for private distribution in 
 1865. 
 
 An Elementary Treatise on Partial Differential Equations. 1866. 
 
 On Sound and Atmospheric Vibrations, with the Mathematical Elements 
 of Music. The ist Edition in 1868, the 2nd in 1871. 
 
 A Treatise on Magnetism, published in 1870. 
 
 Notes on the Earlier Hebrew Scriptures, published in 1876. 
 
 Numerical Lunar Theory, published in 1886. 
 
INDEX. 
 
 Accidents (see also Illnesses) 125, 165, 
 
 182, 281, 327 
 Accounts 2, 361 363 
 Acts and Opponencies 35, 38, 40 43 
 Adams, Prof. J. C. 116, 165, 169, 181, 
 214, 216, 266, 274, 276, 337, 360, 
 362 
 
 Adams, John Quincey 139 
 Agrarian fires 92 
 Aiken 151 
 Airy, William, father of G. B. A. 14, 
 
 15, 17, 19, 21, 34, 67, 7174 
 Airy, Ann, mother of G. B. A. 14, 15, 
 
 50, 56, 67, 73, 8r, 91, 141, 148 
 Airy, William, brother of G. B. A., 
 and Basil R. Airy, his son 15, 20, 
 40, 60, 6365, 67, 69, 74, 83, 103, 
 105, 129, 137, 143, 149, 168, 172, 
 249, 306, 358 
 
 Airy, Arthur, brother of G. B. A. 15 
 Airy, Elizabeth, sister of G. B. A. 15, 
 24, 40, 50, 51, 64, 76, 81, 90, 91, 
 137, 138, 141, 148, 327 
 Airy, Richarda, wife of G. B. A. 56 
 60, 71, 89, 90 92, 94, 96, loo 
 103, 106 108, in, 113, 119, 124, 
 132, 137, 140, 141, 148, 151, 183, 
 187, 205, 214, 225, 231, 242, 245, 
 248, 253, 287, 293, 310 
 Airy, children of G. B. A. 
 George Richard 93, 140, 141 
 Elizabeth 98, 207, 208, 212, 214 
 Arthur 103, 140 
 Wilfrid 129, 218, 225, 228, 231, 238, 
 
 242, 245, 258, 272, 353 
 Hubert 137, 225, 231, 238, 241, 242, 
 
 248, 258, 261, 272, 288, 290, 296 
 Hilda 143, 148, 242, 258, 272, 293 
 Christabel 153, 272, 281, 288, 290, 
 
 310, 318, 320, 347 
 Annot 160, 253, 281, 293, 296, 310, 
 
 318, 320, 347 
 Osmund 172, 248, 253, 261, 263, 281, 
 
 293, 323, 363 
 Allsop 100 
 Alnwick 14, 50, 272 
 Altazimuth instrument 158, 159, 165, 
 
 195, 212, 228, 232, 236, 270, 301, 
 
 333 
 
 Althorp, Lord 95, 100 
 
 American Observatories 139, 151, 263 
 
 American method of recording Obser- 
 vations (see Galvanic Registration) 
 
 Ampere 69 
 
 Ancient eclipses 206, 213, 217, 229, 
 230, 260 
 
 Anderson, lessee of Harton Colliery 
 220 
 
 Anemometer (see Meteorology) 147, 
 W 330, 334 
 
 Anniversary parties 310, 344, 366 
 
 Antiquarian researches and notes 207, 
 220, 238, 320, 323, 359, 360, 361 
 
 Arago 69, 97, 186 
 
 Architecture (see Cathedrals, &c.) 
 
 Astronomical Society (see Royal Astr. 
 Soc.) 
 
 Astronomische Gesellschaft 343 345, 
 
 367 
 Athenaeum newspaper 179, 204, 217, 
 
 219* 2 33> 234, 237, 240, 359 
 Athenaeum Club 62 
 Atkinson, Senior Wrangler 1821, 30 
 Atlantic cable 230 
 Atmospheric railway (see Railways) 
 Auckland, Lord 104, 108, 109, 124, 
 
 185 
 
 Aurora Borealis 294 
 Australian Observatories (see also Ob- 
 servatories) 204 
 Auwers, Dr 343345 
 Babbage, Charles 24, 37, 48, 70, 92, 
 
 152, 238 
 Baily, Francis 87, 91 93, 95, 98, 101 
 
 103, 125, 127, 130, 133, 134, 
 
 139, 144, 158, 165, 172 
 Bakhuysen, of Leyden 331 
 Balance (Public Balance) 304 
 Baldock, Commander 213 
 Baldrey, assistant 87, 89, 114 
 Banks, optician 38 
 Baring, Sir T. no, 204, 206 
 Barlow, Prof. 79, 134, 171, 176 
 Barlow, W. H. 303, 331 
 Barnard, Proctor 91 
 Barnes, Miss 138 
 Barnes, Gorell 264 
 Barometers 291, 301, 304, 319 
 Barry, Sir C. 217 
 Barton, Bernard 17 
 
 Baxter, secretary to the Admiralty 290 
 Beacons, floating 230 
 
406 
 
 INDEX. 
 
 Beaufort, Captain 93, 95 97, IOT, 
 
 102, 124, 125, 132134, 138 
 Beaumont's Observatory 104 
 Bedingfield, pupil 29 
 Bell Scholarships (see Examinations) 
 Bessell, astronomer 76, 98, 99 
 Biddell, Arthur, uncle of G. B. A. 16, 
 
 i7 *9, 23, 7 1 , 9L 9 2 IIO I2 9 
 
 132, 160, 242 
 Biddell, George, uncle of G. B. A. 67, 
 
 172, 208 
 
 Biddell, William, uncle of G. B. A. 56 
 Biddell, George Arthur, son of Arthur 
 
 Biddell 171176, 180, 188 
 Biographical notes 295, 296 
 Bissett, pupil 50 
 Blackwood, Captain 206, 210 
 Blakesley, Canon 161 
 Blasting 138, 146, 160, 163 
 Bliss's observations 157, 159 
 Blomfield, G. B., pupil 32 
 Bloomfield, Lord 188, 190 
 Board of Longitude 72 74, 76, 77, 
 
 7982, 85, 141, 231 
 Boileau 27 
 Bond, G. P. 230 
 
 Books, written by G. B. A., Appendix 
 Book Society, Cambr. 55 
 Bosanquet 206 
 Bouch, T. Civ. Eng. 303 
 Boundary of Canada (see Canada) 
 Bouvard, E. 69, 76, 77, 134, 165 
 Bowstead, 109 
 Bradley's observations 102, 157, 159, 
 
 243 
 
 Brazil, Emperor of 295, 298, 355 
 Breakwaters (see Harbours) 
 Breen, assistant 157, 206 
 Brewster, Sir D. 95, 96, 100 
 Bridges 64, 77, 180, 185, 189, 197,228, 
 
 271, 3 02 , 3>3 33', 356 
 Brinkley, Dr 75 
 Bristow, Miss 149 
 Britannia Bridge (see Bridges) 
 Brooke, Charles 171, 179, 195 
 British Association 94 97, 99, 103, 
 
 130, 143, 165, 169, 170, 187, 205, 
 
 206, 213, 244, 247, 358 
 Brougham, Lord 101, 103 
 Browne, G. A. 86 
 Brunei, Civ. Eng. 175 
 Buck 124 
 Buckland, Dr 91 
 Buckle, pupil 35, 36, 39, 40, 51 
 Burgoyne, Sir J. 157 
 Burlington, Lord 131, 136, 187 
 Burton 323 
 Busts (see Portraits) 
 Calculating machines 37, 152, 230 
 Calvert 60 
 
 Cambridge Observatory : 
 Assistants 87, 98 
 
 Cambridge Observatory : 
 
 Instruments 84, 89, 90, 92, 94, 96 
 
 98, 100, 104, no, 114 116, 125, 
 
 129, 132, 138, 151, 165 
 Printed observations 85, 87, 88 91, 
 
 93' 96, 99 Io8 ' IIO > "4 " 6 
 
 i*5' T 32 
 General 78 87, 90 94, 97, 103, 
 
 108, in, 114 116, 129, 216, 365 
 Cambridge University 227, 230, 232, 
 
 237, 247, 251, 287, 332 
 Cambridge Observatory, U.S.A. 271 
 Canada boundary 160, 167, 168 
 Cankrein, pupil 53, 72 
 Canning, Lord 160, 180 
 Cape of Good Hope, Observatory and 
 
 Survey 95, 96, 101, 104, 131 133, 
 
 140, 142, 153, 158, 201, 205, 206, 
 
 219, 244, 252, 253, 288, 326, 332 
 Carpenter, assistant 302 
 Cartmell, Dr 266269 
 Case 144, 145 
 
 Catalogues of stars (see Stars) 
 Cathedrals and churches 50, 83, 145, 
 
 147, 149, 155, 176, 210, 361, 362 
 Catton 78 
 Cavendish experiment 130, 133, 139, 
 
 148 
 
 Cayley, Prof. 273280, 309, 327, 355 
 Challis, Prof. 34, 91, 138, 151, 165, 
 
 169, 181 
 
 Chalmers, Dr 51 
 Cherbourg (see Harbours) 
 Chesil Bank 155, 156 
 Childers 27, 28 
 Childers, First Lord of Admiralty 286, 
 
 290 
 
 Christchurch 154, 155 
 Christie, Prof. 126, 134, 185 
 Christie, Astronomer Royal 288, 318, 
 
 3^0, 335, 353' 360 
 Chronographic barrel (see Galvanic 
 
 Registration) 
 Chronometers 67, 68, 85, in, 124, 127, 
 
 i33 ^S, H 1 * J 53, r 58, 205, 219, 
 
 244, 258, 259, 260, 270, 280, 289, 
 
 302, 307* 313' 322, 335, 3^5 
 Churches (see Cathedrals) 
 Church service 355, 356 
 Cincinnati Observatory 151 
 Clarendon, Lord 227 
 Clark, Latimer 217 
 Clarkson, Thomas, and Mrs Clarkson 
 
 17, 1923, 31, 62, 64, 234, 313, 
 
 327329 
 
 Cleasby, pupil 64, 72 
 Clegg 157 
 
 Clinton, pupil 50, 53, 64 
 Clocks, 158, 180, 187, 201, 206, 207, 
 
 213, 215 218, 220, 223, 226,240, 
 
 270, 293, 3 OI 3 6 , 32i, 324, 366 
 Cockburn, Sir G. 178 
 
INDEX. 
 
 407 
 
 Coinage (see Decimal Coinage) 
 Colby, Col. 91, 95, 140, 148, 152, 202, 
 
 357 
 
 Colchester 15 21, 141, 318, 362 
 
 Colenso, Bishop 264, 265, 310 
 
 College Hall 4547 
 
 Collorado, Count 188 
 
 Colonial Observatories (see Observa- 
 tories) 179 
 
 Comets 83, 86, 95 97, no, 133, 169, 
 180, 195, 201, 204, 232, 307 
 
 Commissions 133, 134, 139, 151, 158, 
 165, 169, 171, 175, 176, 180, 196, 
 217, 224, 228, 237, 240242, 247, 
 257, 280, 281, 287, 301, 331, 335 
 
 Compass corrections 134 136, 139, 
 140, 165, 219, 224, 228, 237, 260, 
 3 r 3 3^0, 359, 363, 364 
 
 Cookson, Dr 282 284 
 
 Cooper, pupil 62, 63 
 
 Cooper's telescope (see Telescopes) 108 
 
 Copying press 123 
 
 Corbaux, Miss 204 
 
 Corryvreckan whirlpool 248 
 
 Courtney, Rev. J. 92, 137, 148 
 
 Cowper, First Commissioner of Works 
 240 
 
 Crawford, pupil 76 
 
 Criswick, assistant 221, 246 
 
 Cropley, 67, 69, 71, 73 
 
 Crosse, Rev. E. 17, 19, 20 
 
 Cubitt, Sir W. 17, 34, 56, 73, no, 
 163 
 
 Daguerrotypes 144 
 
 Dalhousie, Lord 171 
 
 Davy, Sir Humphrey 54, 55, 67 
 
 Davy, Dr 70, 80, 81, 100 
 
 Daynou, Lieut. 227 
 
 Deal time ball 213, 216, 217, 218, 222, 
 228, 231 
 
 De Berg 187 
 
 Decimal coinage and decimal sub- 
 dividing 204, 217, 224, 281 
 
 Dee navigation (see Rivers) 
 
 Degrees (see also Orders and Elections 
 to Societies) 40, 61, 69, 165, 195, 
 196, 251, 272, 311 
 
 Deighton, publisher 67, 90 
 
 De La Rive 233 
 
 De La Rue 241, 295, 302, 348 
 
 De Launay 293, 296, 303 
 
 Deluge, The 220 
 
 De Morgan, A. 227 
 
 Denison, E. B. 180, 207, 213, 217 
 
 Denison, Sir W. 133, 184 
 
 Denison, H. 207 
 
 Denmark, King of 169, 195, 204 
 
 Dent, clockmaker 158 
 
 Dent-dale 149, 150 
 
 Devonshire, Duke of 251 
 
 Dobbs, pupil 6 1 63, 65, 69 
 
 Dobree, lecturer 27, 30 
 
 Docks (see Harbours) 
 
 Dolcoath experiments 66 68, 71, 79, 
 
 83, 84 
 
 Dollond, instrument maker 71, 92, 330 
 Drainage 196, 231, 366 
 Drinkwater, Bethune 27, 32 36, 38 
 
 40, 5052, 134 
 
 Double-image micrometer 139, 141, 330 
 Douglas, Sir H. 228 
 Dover (see Harbours) 
 Dublin professorship (see Professorships) 
 Dublin Observatory (see Observatories) 
 
 108 
 
 Due, Baron 211 
 Dundas, Admiral 207 
 Dundonald, Lord 180, 183, 184 
 Dunkin, assistant 206, 210, 221, 243,246 
 Dunlop, astronomer 96 
 Durham observatory 139 
 Earnshaw 79 
 Earth currents 239, 245, 260, 281, 285, 
 
 ^86, 333 
 
 Eastons, manufacturers 77 
 Eclipses (see also Ancient Eclipses) 
 
 104, 115, 127, 151, 154, 186, 206, 
 
 208, 209, 227, 232, 241, 242, 244, 
 
 271, 292, 333 
 
 Edinburgh Observatory 101, 230, 232 
 Edmonston, Dr 208 
 Education (see University Education) 
 Egyptian Astronomical Tablets 224 
 Elections to societies, &c. (see also 
 
 Degrees and Orders) 50, 62, 64, 
 
 83, 89, 108, 127, 217, 297, 311 
 Electricity, atmospheric 165, 215, 319, 
 
 3 2 4 330 
 
 Ellenborough, Lord 178 
 Ellis, W., assistant 221, 224, 237, 304, 
 
 308 
 
 Elphinstone 52 
 Encke and Encke's Comet 83, 95 97, 
 
 i33 !83 
 
 Encyclopaedia Metro politana 63, 65, 
 
 67, 69, 83, 89, 94, 142, 152, 166 
 Engines (see Steam-engines) 
 Equatoreal, large 224, 227, 229, 231, 
 
 236, 241, 243, 263, 287, 288, 292, 
 
 304, 306, 307 
 Estcourt, Col. 167 
 Evans, lecturer 23, 32 
 Examinations 72, 74, 79, 86, 89, 93, 
 
 95, 98, 102, 105, 185, 237 
 Exhibitions and prizes 24, 27, 31, 38, 
 
 49> 313 
 
 Exodus of the Israelites 204 
 Eye, defects of 61, 63, 65, 220, 237, 
 
 244 
 
 Eye, estate at 132, 143 145 
 Fallows, astronomer 95, 201 
 Faraday 93, 95, 2 1 7, 244 
 Farish 52 
 Farr 230 
 
408 
 
 INDEX. 
 
 Fellowship 53, 61, 69 
 
 Field 27, 38, 41, 61 
 
 Fisher 39 
 
 Fishmongers' Company 24 
 
 Fletcher, Isaac, M.P. 272,. 288, 323 
 
 Floating Island, Derwentwater 320 ?' 
 
 Fluid telescope, Barlow's 79 
 
 Foley 39 
 
 Forbes, Prof. J. D. 126, 179, 196, 204 
 
 Foster, Messrs 189 
 
 Fox, Alfred 173 
 
 Freedom of the City of London 311 
 
 3H 
 
 Freemantle, Sir T. 204 
 
 French, Dr 70, 78 
 
 Friends, Personal friends at Cam- 
 bridge 116 122 
 
 Fries, Prof. 210 
 
 Galbraith 84 
 
 Galle 181, 183, 188 
 
 Galvanic communication, Time-signals, 
 Clocks, and Registration (see also 
 Earth currents) 201, 203, 204, 
 206, 211, 213, 215 218, 222, 223, 
 226, 228, 230, 231, 233, 240, 244, 
 256, 258, 259, 262, 263, 280, 302, 
 326, 331, 333 
 
 Gambard 88 
 
 Gas Act 237 
 
 Gauss 126, 139, 183 
 
 Gautier 88, 233 
 
 Geodesy 240, 323, 353 
 
 Geology 55, 84, 91, 100, 353 
 
 Geological Society 89 
 
 Germany 302 
 
 Gibson, pupil 32, 36, 39, 40, 52 
 
 Gilbert, Messrs 77 
 
 Gilbert, Davies 79, 87, 89, 96, 134 
 
 Gill, astronomer 318, 322, 326, 332 
 
 Gladstone, W. E. 179, 217, 336 
 
 Glaisher, assistant 98, 104, 109 nr, 
 115, 129, 130, 132, 142, 148, 185, 
 216, 304 
 
 Glasgow Observatory 139, 143 
 
 Gordon 72 
 
 Gosset 202 
 
 Goulburn, Chancellor of the Exchequer 
 151, 152, 162 
 
 Gould, Dr B. A. 271, 301, 343 
 
 Goussel 62 
 
 Graduation of circles 194 
 
 Grant, of Glenmoriston 96 
 
 Great Circle sailing (see Navigation) 
 
 Great Eastern (see Ships) 
 
 Great Exhibition 206, 207 
 
 Great Gable 148, 220 
 
 Green, Commander U.S.N. 331 
 
 Greenwich 187, 367 
 
 Greenwich Observatory, before his ap- 
 pointment as Astronomer Royal 
 54, 55, 68, 76, 80, 82, 85, 88, 90, 
 9296, 99, 103 
 
 Greenwich Observatory: 
 
 Appointment as Astronomer Royal, 
 and subsequently as Visitor 103 
 105, 108, 109, 222, 306, 335337, 
 339, 340, 346, 354 
 
 Buildings and grounds in, 123, 124, 
 126, 131, 133, 139, 168, 194, 200, 
 205, 216, 224, 242, 245, 259, 262, 
 269, 280, 285, 315, 321, 329 
 
 Instruments j 30, 133, 139, 157 159, 
 180, 182, 184, 185, 194, 205, 214, 
 215, 218, 224, 226, 229, 231, 238, 
 240, 243, 257, 259, 262, 269, 270, 
 287, 286, 288, 291, 293, 301, 302, 
 304, 306, 315, 318, 320, 321, 331, 
 
 333, 353 
 Assistants 109, 129, 130, 157, 201, 
 
 21-6, 238, 290, 296, 304, 341, 342, 
 
 367, 368 
 
 Computations 244, 280 
 Papers and manuscripts (arrange- 
 ment of) 123, 131, 158, 1 68, 179, 
 
 280, 324 
 
 Estimates 151, 178, 269, 290, 326 
 Printed Observations 138, 152, 153, 
 
 157, 165, 195, 218, 263, 319, 324, 
 
 326, 363 
 Visitations and Reports 125, 141, 
 
 i53> 157, !59> l6 , l8l > J 82, 184, 
 185, 203, 205, 212, 215, 216, 224, 
 
 226, 231, 232, 236, 240, 246248, 
 258, 262, 271, 289, 290, 293, 295, 
 
 303, 39, 3 2 6, 335, 337339 35", 
 
 360, 362, 363, 365 
 General 132, 141, 160, 179, 240, 
 
 310, 360 
 Gresswell 224 
 
 Groombridge's Catalogue (see Stars) 
 Guest, Caius College 52, 61, 108, 188 
 Haarlem 211 
 Hall, Col. 202 
 
 Halley and Halley's Comet 1 10, 2 19, 29 1 
 Hamilton 38, 41, 207 
 Hamilton, Sir W. R. 75, 196 
 Hamilton, Admiral 240 
 Hansard 76 
 Hansen, Prof. 181 183, 185, 204, 219, 
 
 227, 229, 235, 236, 238, 239, 244 
 Hansteen 206 
 
 Harbours 169, 170, 176, 177, 217, 228 
 Harcourt, Rev. W. Vernon 94, 97, no, 
 
 175, *7<5 
 
 Hartnup, astronomer 129, 130, 365 
 Harton Colliery experiments 220, 221, 
 
 223 
 
 Haviland, Dr 8, 148, 162 
 Hawkes, Trinity College 40 
 Hebrew Scriptures 204, 220, 309, 358 
 Heliograph 302 
 Hencke 168 
 
 Henderson, astronomer 96, 101, 131 
 Henslow, Prof. 91 
 
INDEX. 
 
 409 
 
 Herbert, G. 230 
 
 Hereford 15, 225, 320 
 
 Herschel, Sir John 24, 38, 48, 54, 55, 
 67, 69, 74, 75, 82, 85, 89, 91, 93, 
 94, 99, 100, 101, 114, 116, 132, 
 140, 142, 153, 160, 163, 207, 220, 
 221, 223, 233, 244, 297 
 
 Herschel, Miss Caroline 183 
 
 Herschel, Col. J. 359 
 
 Hervey, pupil 53 
 
 Higman, Tutor, Trinity College 39, 
 53, 61, 62, 70 
 
 Hilgard, U.S.A. 301 
 
 Himalaya Expedition (see Eclipses) 
 
 Hind, Moderator 39 
 
 Hind, Superintendent Nautical Al- 
 manac 142, 180, 201, 210, 212, 
 216, 244 
 
 Hopkins 109 
 
 Hovenden, pupil 63 
 
 Hudson 175 
 
 Huggins, Dr 316, 344, 363 
 
 Humboldt, Baron A. jt^6j 188 
 
 Humphreys 206, 209, 210 
 
 Hussey, Dr 134 
 
 Hustler, Tutor, Trinity College 21, 22, 
 24, 25, 27, 28, 33, 41 
 
 Hyde Parker, Admiral 183 
 
 Hygrometers 103 
 
 Ibbotson, pupil 69 
 
 Iliff 27 
 
 Illnesses 101, 129, 173, 182, 183, 327, 
 353. 360, 362367 
 
 Inequality, Venus and Earth 77, 78, 
 94, 98, 99 
 
 Inglis, Sir R. 179 
 
 Institut de France 104, 105, 297 
 
 Institution of Civil Engineers 152, 207, 
 271 
 
 Inverness, Northern Institution of 64 
 
 Ipswich Lectures 195 197, 362 
 
 Ireland, notes of 163, 164 
 
 Ivory 75 
 
 Jackson 83 
 
 Jackson, John 360 
 
 James, Sir H. 220, 240 
 
 Janus (see Steam-engines) 
 
 Jarrow (see Harbours) 
 
 Jeffries 3840 
 
 Jerrard, Dr 136 
 
 Jervis, Major 140 
 
 Jeune, Dr, V. C. of Oxford 243 
 
 Johnson, Capt. 134 
 
 Johnson, astronomer 238 
 
 Jones, instrument-makers 77, 83, 84, 
 
 94, 96, 97 
 
 Jones, R. 09 
 
 Journeys : 
 
 Scotland and Cumberland 50; Swan- 
 sea 52 ; Derbyshire, &c. 60 ; Wales 
 64; Keswick, &c. 64; Cornwall, 
 &c. 67, 68 ; Orleans 69 ; Lake 
 
 District, &c. 76; Continent, Ob- 
 servatories, &c. 88 ; Cornwall, &c. 
 83, 84; Derbyshire 90; Oxford 
 &c. 91; Cumberland 91 ; Ireland 
 94; Scotland 96; Derbyshire, &c. 
 100; Cumberland, &c. 103; Ire- 
 land 1 08; Kent 129; S. Wales 
 132; Luddington and Yorkshire 
 137 ; Border of Scotland 143 ; 
 S. Wales 148 ; Cumberland and 
 Yorkshire 148 150; South of Ire- 
 land 1 60 ; Ireland 168 ; France 
 172; Cornwall 172; Germany 183; 
 Petersburg, &c. 188; Ireland 196; 
 Shetland 202 ; Scotland 205 ; 
 Sweden 208 211; Madeira 214; 
 Cumberland 217 ; Cumberland 
 221; Oban, &c. 225; Italy and 
 Sicily 228; West Highlands 231; 
 Switzerland 233; Central France 
 238 ; Spain (eclipse) 242 ; Cumber- 
 land 245 ; West Highlands 248 ; 
 West Highlands 253; Cumberland 
 261 ; Norway 263 ; Cumberland 
 272; Switzerland 281; Cumber- 
 land 288 ; Cumberland 290 ; Cum- 
 berland 293; Scotland 296; Scot- 
 land 306; N. of Scotland 318; 
 Ireland 320; Scotland, &c. 324; 
 Cumberland 327 ; Cumberland 
 332; Cumberland 350; Cumber- 
 land 352; S. Wales 354; Cum- 
 berland 358; Cumberland 362 
 
 Julius Caesar, landing of 207 
 
 Jupiter (see Planets) 97, 99, 104, 115, 
 116, 127, 307, 319 
 
 Keeling 18 
 
 Kennedy 90 
 
 King, Joshua 70, 78 
 
 Kingstown 253 
 
 Knight, publisher 103 
 
 Knighthood, offers of in 113, 187, 
 254 2 56, 296 
 
 Lagarde 69, 88 
 
 Laing 171 
 
 Landman, engineer 126 
 
 Langton 272, 288, 290, 293, 296, 306 
 
 Laplace 69, 79, 99 
 
 Lardner, Dr 75 
 
 Lassell, and Lassell's telescope 195, 
 196 
 
 Latitude determinations 83, 114 
 
 Lax, Prof. 40, 72, 85, 87 
 
 Lectures : 
 
 College 62, 6567, 70 
 Professorial 71 77, So, 87, 90, 93, 96, 
 99, 102, 104, 108, 113, 114, 124, 
 125 
 
 Miscellaneous 70, 132, 142, 169, 195, 
 196, 206, 207, 217, 230, 233, 244, 
 260, 287, 323, 362, 367 
 
 Lefevre, J. G. S. 134, 171 
 
INDEX. 
 
 Leitch, Dr 220 
 
 Le Verrier 181, 187, 233, 257, 317 
 
 Lewis, H. 52 
 
 Lewis, Sir G. C. 224, 254 
 
 Lightfoot, Rev. Dr 285 
 
 Lighthouses 51, 225, 240 242, 355 
 
 Lightning 262 
 
 Lillingstone 96 
 
 Lindsay, Lord 326 
 
 Listing, Prof. 343, 353 
 
 Liverpool Observatory 139, 151, 179, 
 196, 201, 253, 365 
 
 Livingstone, Dr 230 
 
 Lloyd, Dr 75 
 
 Lloyd, Prof. 1 26 
 
 Lockyer 362 
 
 Lodge 83, 88 
 
 London University 131, 136, 139, 148, 
 1 80, 1 86 
 
 London, Freedom of the City 311 314 
 
 Long vacations, with pupils 52, 64, 69 
 
 Longitude determinations 85, 91, 93, 
 158, 160, 166168, 216, 219, 223, 
 227, 230, 232, 240, 246, 253, 263, 
 271, 301, 319, 325, 331, 332 
 
 Longitude, Board of (see Board of Longi- 
 tude) 
 
 Lowe, Chancellor of the Exchequer 220 
 
 Lubbock, Sir John 98, 99, 127, 130, 131, 
 134, 136, 142, 238 
 
 Lucas (computer) 233 
 
 Lucasian Professorship (see Professor- 
 ships) 
 
 Lunar Reductions 127, 130, 133, 139, 
 142, 148, 151, 153, 158, 165, 181, 
 185, 195, 214, 235, 239 
 
 Lunar Theory and Tables (see also 
 Numerical Lunar Theory) 127, 131, 
 185, 204, 227, 229, 235, 236, 239, 
 
 244 313. 354> 36o 
 
 Lyndhurst, Lord 105, 162, 168, 171 
 
 Lyons, Sir E. 209 211 
 
 Macaulay, T. B. 61 
 
 Macdonnell, Dr 75 
 
 Maclean, of Loch Buy 96 
 
 Maclear, Astronomer 92, 93, 101, 131, 
 133' r 5 8 2I 9 238, 2 44. 253 
 
 Madras Observatory 101 
 
 Magnetic Observatory and Magnetism 
 (see also Meteorology, Compass 
 corrections, and Earth currents 124, 
 126, 131, 133, 139, 141, 142, 148, 
 151, 165, 169, 170, 171, 179, 185, 
 I95> 2 >3. 215, 216, 222, 224, 233, 
 239, 240, 244248, 252, 256, 257, 
 259, 260, 263, 281, 287, 291, 292, 
 294, 302, 304, 319, 325, 326, 330, 
 
 334, 357. 358 
 
 Main, Robert 109, no, 216, 238 
 Maine Boundary (see Canada) 
 Maiden, Prof. 207, 220 
 Malkin 27, 52, 63 
 
 Malta 320 
 
 Man-Engines (see Mines) 
 
 Manuscripts (see Papers) 
 
 Mars (see Planets) 116, 252, 318 
 
 Marshman, pupil 64, 65 
 
 Marth, A. 240 
 
 Martin, Trin. Coll. 161 
 
 Maskelyne, astronomer 102, 128, 159 
 
 Mason 39 
 
 Mathematical Investigations (see also 
 
 Appendix "Printed Papers") 224, 
 
 240, 247, 355, 357 
 Mathematical Tracts 65 67, 90, 94, 
 
 233 
 
 Mathematical subjects in 1819, 47, 48 
 Maudslays and Field 218 
 May, Ransomes and May 158, 194 
 Medals 95, 98, 104, 169, 180, 193, 272, 
 
 320 
 
 Melbourne University 220 
 Melville, Lord 87 
 Mercury (see Planets) 286 
 Merivale, Dr 327, 328 
 Meteorology 116, 147, 168, 179, 232, 
 
 270, 271, 281, 289, 291, 292, 301, 
 
 303, 304, 3 l6 3!9> 322, 324, 326, 
 
 330, 33L 334, 355357 
 Meteors 270 
 Middleton, Sir W. 207 
 Milaud 209, 210 
 Military researches 238 
 Miller, Prof. 102, 158, 237 
 Mines 66, 67, 71, 76, 79, 83, 84, 172 
 
 175, 189 
 
 Minto, Lord 124, 135, i f2 
 Mitchell, astronomer 151, 203 
 Mitchell Miss 195 
 Molesworth, Sir W. 217 
 Monteagle, Lore} 237 
 Monument in Playford church 137 
 Moon: 
 
 Observations of 158 160, 195, 214, 
 
 230, 235, 263, 307, 316, 324 
 Theory and Tables of (see Lunar 
 
 Theory and Tables) 
 Reductions of Observations of (see 
 
 Lunar Reductions) 
 Mass of 88, 89 
 Morpeth, Lord 196 
 Morton, Pierce, pupil 52, 108, 205 
 Murchison, Sir R. 213 
 Murray, publisher 176 
 Musgrave, Charles 21, 22, 34 
 Musgrave, T. Archbishop 21, 22, 85 
 Myers 27, 31, 33, 39, 265 
 Nasmyth 169 
 Nautical Almanac 74, 76, 77, 85, 87, 
 
 91, 92, 104, 214, 216, 331 
 Navigation 233, 313, 365 
 Neate, pupil 53 
 Neptune and Uranus 133, 134, 165, 169, 
 
 181, 183, 186 
 
INDEX. 
 
 411 
 
 Newall 306, 318 
 
 Newcombe, Prof. 343 
 
 New Forest 155 
 
 Northampton, Lord 142, 144 
 
 Northumberland Telescope 100, 104, 
 no, 125, 132, 138, 151, 165 
 
 Numerical Lunar Theory 293, 296, 303, 
 305, 308, 317* 3 J 9 3 2 <> 323. 3 2 5, 
 335, 346350. 354 356, 358, 360 
 362 
 
 Observatories: see 
 
 American, Australian, Beaumont's, 
 Cambridge, Cambridge U.S.A., 
 Cape of Good Hope, Cincin- 
 nati, Colonial, Dublin, Durham, 
 Edinburgh, Glasgow, Greenwich, 
 Liverpool, Madras, Oxford, Paris, 
 Paramatta, Pulkowa, St Helena, 
 Williamstown 
 
 Occultations 227 
 
 O'Connell 163, 164 
 
 Ogilby, pupil 65, 69 
 
 Oppolzer, Prof. 325 
 
 Opponencies (see Acts and Opponencies) 
 
 Optics 55, 75 77, 87, 90, 92, 93, 95, 
 in, 220, 323, 336, 363 
 
 Orders (see also Degrees and Elections 
 to Societies) 187, 191 193, 220, 
 256, 293, 296, 298, 304, 311 
 
 OuvarofT, Count 188, 191 193 
 
 Oxford Observatory 142 
 
 Oxford, Miscellaneous 165 
 
 Packington, Sir J. 233 
 
 Palmerston, Lord 256 
 
 Papers (see Appendix " Printed Papers") 
 
 Papers, Arrangement of 123, 131, 158, 
 168, 179, 280 
 
 Parachute, Fall of 1 30 
 
 Parallax (see Sun) 
 
 Paramatta Observatory 96, 179 
 
 Parker, Charles 1 1 1 
 
 Parker, Vice-Chancellor 49 52 
 
 Paris, Dr 66, 67 
 
 Paris Observatory 223, 257, 269, 290, 
 
 291, 301 
 s Exhibition, 222 
 
 Paris 
 
 Parliamentary Elections 98, 104, 130 
 
 Pasley, Col. 146 
 
 Paul 142 
 
 Peacock, George 22, 23, 25, 26, 28, 31 
 
 33, 35, 3 8 > 40, 45, 48, 49 53, 55, 
 63, 66, 69, 70, 77, 119121, 134, 
 152, 154, 161, 165, 182 
 
 Pearson, Dr 85 
 
 Peel, Sir Robert 105 108, 151, 179 
 
 Pendulum Investigations and Experi- 
 ments 66, 67, 71, 79, 83, 84, 220, 
 221, 223,359 
 
 Penny Cyclopaedia 97, 101, 132 
 
 Pension 105 108, 306 
 
 Pentland 104, 105 
 
 Percy, Bishop 218 
 
 Personal sketch i 13 
 
 Philosophical Society, Cambridge 35, 
 
 38, 50, 55, 63, 65, 70, 75, 85, 89, 
 
 92, 93, 95, 99, 101, 104 
 Philpott, Dr 233 
 Photography 230, 239, 241, 247, 295, 
 
 302, 305, 307, 308, 316-319, 323, 
 
 3*4, 33i 
 
 Piers (see Harbours) 
 
 Pinheiro, Lieut. 355 
 
 Pipon, Lieut. 160 
 
 Plana, astronomer 88 
 
 Planetary influences 249, 250 
 
 Planetary Reductions 98, 100, 102, 104, 
 no, 130, 133, 139, 142, 148, 153, 
 180, 263 
 
 Planets (see also Transits of Venus) 77, 
 78, 82, 94, 9799, 104, 115, 116, 
 127, 133, 134, 165, 168, 169, 181, 
 183, 186, 195, 198, 200, 2or, 212, 
 247, 252, 257, 263, 286, 291, 307, 
 315, 318, 319, 322, 324 
 
 Plantamour 234 
 
 Playford 182, 320, 353, and frequently 
 throughout 
 
 Plumian Professorship (see Professor- 
 ships) 
 
 Pocket-books for Observations 116 
 
 Pogson, astronomer 221 
 
 Pond, astronomer 73, 76, 80, 82, 87, 
 
 93, 123, 127129 
 dock, Capt. 95 
 
 Portlock, 
 
 Portraits, busts, &c. 50, 102, 354 
 
 Post Office, (clocks, &c.) 223, 226, 331, 
 
 Post Office, stamps and envelopes 144 
 
 Pouillet 69 
 
 Prince Albert 162, 207 
 
 Pritchard, Rev. C. 215, 358, 362 
 
 Prizes (see Exhibitions) 
 
 Probable errors 240 
 
 Professorships : 
 
 Dublin 75 ; Lucasian 69 71 ; Plu- 
 
 mian 77 81, 86, 89, 92, 93, no 
 Public Schools Commission 247 
 Pulkowa Observatory 188 193, 252, 
 
 Pupils : 
 
 Bedingfield 29; Bissett 50; Blom- 
 field 32 ; Buckle 35, 36, 39, 40, 51; 
 Cankrein 53, 72; Cleasby 64, 72; 
 Clinton 50, 53, 64 ; Cooper 62 ; 
 Crawford 76; Dobbs 61 63, 65, 
 69; Gibson 32, 36, 39, 40, 52; 
 Guest 52, 61, 108; Hervey 53; 
 Hovenden 63 ; Ibbotson 69; Lewis 
 52; Marshman 64, 65 ; Morton 52, 
 108, 205; Neate 53; Ogilby 65, 
 69 ; Parker 49 52 ; Rosser 29, 30, 
 32; Smith 64; Tinkler 69; Tot- 
 tenham 64; Turner 53, 61 63, 
 72,73; Wigram64; Williamson 49 
 
412 
 
 INDEX. 
 
 Pym, Engineer 157 
 
 Queen, H. M. the Queen, 161, 317 
 
 Queroualle, Mdlle de 360 
 
 Quetelet 88 
 
 Railways, near Observatory 126, 178, ^ 
 
 252, 259, 262, 291, 294 
 Railway Gauge Commission 171, 175, 
 
 176, 180 
 Railways, miscellaneous 138, 143, 156, 
 
 . i57t ^L 354 
 Rain (see Meteorology) 
 Rainbows 357 
 Ransomes, also Ransomes and May 17, 
 
 19, 20, 125, 152, 158, 194, 205 
 Reach 50, 51 
 
 Reflex zenith tube 194, 226 
 Religious tests and views 7, 264, 265, 
 
 284, 285, 309 
 Repsold 1 88 
 Rhodes 131 
 
 Richardson, assistant 98 
 Rigaud, Prof. 87, 96, 102 
 Rivers 207, 213, 217, 232, 334 
 Robinson, Dr 91, 94 
 Robinson, Capt. 160 
 Rogers, Rev. 21 
 Rogers, school assistant 20, 56 
 Romilly, Lord 27, 28 
 Ronalds 179, 195 
 Rose, Rev. H. J. 142 
 Rosse, Lord, and Rosse's Telescope 161, 
 
 179, 196, 198 2OO, 221, 222 
 
 Rosser, pupil 29, 32 
 
 Rothery 351 
 
 Rothman 36, 37, 40 
 
 Round Down Cliff, blasting of 163 
 
 Rouse, Rev. R. C M. 357 
 
 Routh, Dr E. J. 143, 244, 258, 266, 
 272, 293 
 
 Royal Astronomical Society (see also 
 Appendix "Printed Papers") 83, 
 89, 98, 99, 104, 127, 134, 169, 180, 
 181, 186, 201, 202, 204, 206, 213, 
 217, 219, 230, 272, 281, 305, 310, 
 326, 348, 355 
 
 Royal Exchange clock 158 
 
 Royal Institution 206, 217 
 
 Royal Society (see also Appendix 
 " Printed Papers ") 67, 73, 78, 83, 
 92, 94, 95, 103, 127, 142, 148, 169, 
 195, 202, 204, 213, 224, 230, 233, 
 244, 247, 258, 272, 293, 303, 310, 
 
 359 
 
 Royal Society of Edinburgh 108 
 Runcker, Paramatta 54 
 Riincker 188, 220, 221 
 Rundell 237, 363 
 Rusby 38, 41 
 
 Russell, Lord John in, 191, 192 
 Sabine, Col. 223, 233, 240, 247, 248 
 Sadler, H. 326 
 Saint Helena Observatory 127 
 
 Samuda 157 
 
 Saturn (see Planets) 82, 307 
 
 Saunders, G. W. Ry 175 
 
 Saw-mills (see Ship timbers) 
 
 Schehallien, mountain 204 
 
 Scholarship 35, 36 
 
 Scholefield 162 
 
 Schumacher 91, 134, 169, 180, 188, 
 
 195, 201, 214 
 Scientific Manual 185 
 Scoop- wheels 152 
 Scoresby, Dr 219, 237 
 Scriptural Researches (see Hebrew 
 
 Scriptures) 
 Sedgwick, Adam 22, 54, 69, 72, 83, 84, 
 
 98, 100, 119, 136, 140, 149, 153, 
 161, 173, 182, 187, 299, 300 
 
 Selvvyn, Prof. 264 
 
 Senate House Examination (see also 
 
 University Education) 39, 43 45, 
 
 237, 265, 266, 273, 282 284 
 Sewers Commission 196 
 Sheepshanks, Rev. Richard, and Miss 
 
 Sheepshanks 67, 77, 78, 80 85, 
 
 9 2 > 93' 95' 97 9 8 > 100105, 108, 
 
 in, 114, 121, 130, 134, 142, 165, 
 
 202, 224, 227, 230, 301 
 Sheepshanks Fund and Scholarship 227, 
 
 230, 232, 237, 247, 365 
 Shepherd, clock-maker 206, 213, 223 
 Ships 231, 237, 260, 351 
 Ship-timbers, Machinery for sawing, 
 
 152, 169, 187 
 Shirreff, Capt. 152, 183 
 Simmons 221 
 Simms, F. W. 109 
 Simms (see Troughton and Simms) 
 Skeleton forms 37, 102, no, 123, 148, 
 
 1 60 
 
 Sly, draughtsman 151 
 Smith, Rev. R. Smith, father-in-law of 
 
 G. B. A., and Mrs Smith, 5660, 
 
 66, 71, 132, 137, 142, 187, 231, 
 
 238 
 Smith, the Misses Smith, sisters of 
 
 Richarda Airy, Susanna 91, 101 ; 
 
 Elizabeth 99, in, 183; Georgiana 
 
 99, 103, in, 172; Florence, 108; 
 Caroline 138 
 
 Smith, Archibald 237 
 
 Smith, Sir Frederick 171, 175 
 
 Smith, M., pupil 64 
 
 Smith, engineer 156 
 
 Smith's Prizes 40, 49, 72, 79, 86, 89, 
 93> 95 98, 102, 105, 230, 238, 260, 
 309, 3 2 7 
 
 Smyth, Capt. W. H. 88, 91, 93, 157, 
 167, 326, 330 
 
 Smyth, Piazzi 227, 230 
 
 Societies, &c., Elections to (see Elec- 
 tions) 
 
 Solar Eclipses (see Eclipses) 
 
INDEX. 
 
 413 
 
 Solar Inequality (see Sun) 
 
 Solar System (see Sun) 253 
 
 Solar Tables (see Sun) 
 
 South, Sir James 38, 54, 55, 69, 73, 87, 
 
 9193,9699, 103, 157, 179, 185, 
 
 238 
 
 South's Telescope 9799, 103 
 South- Eastern Railway 126, 179, 201, 
 
 203, 206, 218, 233, 262, 294 
 Southampton 154 
 Southey (Poet) 64, 65, 76, 149 
 Spectroscopy 257, 304, 307, 315, 316, 
 
 3i8, 330, 334 
 Spottiswoode 355 
 Spring-Rice, Lord Monteagle 104, 105, 
 
 no 112, 126, 130, 134, 136 
 Standards of Length and Weight, and 
 
 Standards Commission 133, 134, 
 
 139, *5' 5 i5 8 > J 65> 169, 217, 224, 
 
 247, 257, 280, 281, 287, 301, 313 
 Stars 97, 100 102, no, 127, 130, 132, 
 
 i33> l6 5> 20I 2 3 2 53 28 "> 28 9> 
 304, 307, 322, 324, 330, 357, 362 
 Start Point 230, 233, 244, 246, 258, 
 
 309 
 Steam-engines 18, 09, 70, 180, 183, 
 
 184, 2ii 
 
 Stephenson, George 90 
 Stephenson, Robert 90, 178, 180, 204 
 Steventon 109 
 Stewart, Prof. Balfour 357 
 Stjerneld, Baron 209, 210, 211 
 Stokes, Prof. 274, 276, 305, 337, 366 
 Stone, Astronomer 238, 259, 280, 288, 
 
 289, 291, 354 
 
 Stratford, Lieut. 93, 101, 156, 216 
 Stroganoff, Count 188 
 Strutt, Lord Helper 27, 28 
 Strutt, Jedediah 60 
 Struve, Otto 165, 166, 188, 204, 205, 
 
 240, 243, 343, 357 
 Stuart, Prof. J. 350 
 Sun: 
 
 Miscellaneous 227, 253, 304, 307, 316, 
 
 318, 320, 324, 325, 326, 331, 334 
 Parallax of (see also Transits of 
 
 Venus) 230, 252, 318, 322, 323 
 Eclipses of (see Eclipses) 
 Inequality, Venus and Earth 77, 78, 
 
 94, 98, 99 
 able 
 
 Tables of 73, 76, 78 
 Surveys (see Trigonometrical Surveys) 
 Sussex, Duke of, 103 105, 126 
 Sutcliffe 36 
 Sutcliffe, Miss 148 
 Sydney University 207 
 Sylvester 169, 187 
 Sweden, King of 209, 210, 304 
 Tate 27, 28 
 Taylor, architect in 
 Taylor, First Assistant to Pond, 100, 
 124 
 
 Taylor, H. 97, 100, 101, 102, 127 
 Telegraphs (see Galvanic communi- 
 cations) 
 
 Telescopes (see also Cambridge Obser- 
 vatory Instruments, and Greenwich 
 Observatory Instruments) 79, 97, 
 98, 99, 103, 108, 196, 198200, 
 221, 230, 240, 286, 291, 292, 294, 
 306 
 
 Teneriffe Experiment 227, 230 
 Thames, the River, 232, 334 
 Theology (see also Hebrew Scriptures 
 
 and Colenso) 356, 358, 363, 365 
 Thermometers 179, 289, 301, 304, 316 
 Thermo-multiplier 286, 288, 289 
 Thirl wall, Bishop 272 
 Thomas, assistant 130 
 Thompson, Master Trin. Coll. 272 
 Thomson, Sir W. 319, 359, 364 
 Tidal Harbour Commission 169 
 Tides, 142, 148, 152, 154, 165, 169, 
 
 207, 213, 217, 240, 320 
 Time-signals and Time (see also Gal- 
 vanic communication, &c.) 201, 
 213, 215, 216, 222, 228, 230, 233, 
 244, 258, 302, 309, 351, 352, 360, 
 
 367 
 
 Time balls (see Time signals) 
 
 Tinkler, pupil 69 
 
 Tottenham, pupil 64 
 
 Traill, Dr 60, 90 
 
 Transit Circle, 8-inch 185, 194, 205, 
 2ii, 214, 216, 222, 229, 232, 238, 
 243, 257, 262, 263, 269, 288, 291, 
 315, 321, 324, 353 
 
 Transits of Venus 261, 281, 286, 289, 
 292, 295, 302, 304, 305, 308, 313, 
 317, 318, 319, 322, 324, 325, 331, 
 
 335, 346, 35 
 Trigonometrical Survey 85, 95, 127, 
 
 i3 2 !33> r 40 J 4 2 > H 8 * 2 2 f 
 
 253, 269 
 Trinity College, Cambridge 183, 227, 
 
 233 234, 247, 272, 285, 311, 356, 
 
 365, 3^8 
 
 Trinity House 230 
 Tripos Examination (see Senate-House 
 
 Examination) 
 Troughton and Simms 94, 97, 98, 103, 
 
 no, 132, 194, 205, 260, 286, 294, 
 
 302. 315 
 
 Tulley, optician 38, 54, 90, no 
 Tupman, Capt. 302, 323 
 Turner, pupil 53, 6163, 72, 73 
 Turton, Prof. 40, 65, 90 
 Tutorship 53, 61, 62, 6567, 70 
 Ulrich, J. G. 158 
 Universities (see Cambridge, Dublin, 
 
 Edinburgh, London, Melbourne, 
 
 Oxford, Sydney) 
 University Education (see also Smith's 
 
 Prizes and Senate-House Examina- 
 
414 
 
 INDEX. 
 
 tion) 39, 4345, 47 4 8 > I ^'2, 265, 
 266269, 273280, 282284, 
 
 39 3^7, 33^, 361 
 
 University Press, 65, 85, 90, 95, 102 
 
 Uranus (see Neptune) 
 
 Valencia (see also Longitude Deter- 
 minations) 158, 160, 240, 246, 253,- 
 263, 271 
 
 Venus (see Planets, and Transits of 
 Venus) 
 
 Venus and Earth inequality (see Ine- 
 quality) 
 
 Vernon Harcourt (see Harcourt) 
 
 Vetch, Capt. 204 
 
 Vibrations of ground 126, 178, 226, 
 259, 291 
 
 Vignoles, C. B., engineer 156, 241, 242 
 
 Vulliamy, clockmaker 187, 217 
 
 Wales, Prince of 320 
 
 Walker, Byatt 15 
 
 Walker, James, engineer 126 
 
 Walker, Sydney, 30 
 
 Warburton, H. 127, 187 
 
 Washington, Capt. 230 
 
 Water telescope (see also Fluid tele- 
 scope) 240, 286, 291, 294 
 
 Watson 175 
 
 Waves (see Tides) 
 
 Webster, M.P. for Aberdeen 318 
 
 Western 196 
 
 Westminster clock (see also Clocks) 
 187, 207, 213, 217, 240, 270 
 
 Wexford harbour (see Harbours) 
 
 Wheatstone 142 
 
 Whewell, William 22, 25, 26, 31, 33, 
 43. 47, 53, 63, 66, 68, 69, 71, 72, 
 7880, 8385, 90, 100, 103, 105, 
 117119, 142, 148, 150, 152, 161, 
 169, 173, 227, 230, 232, 238, 266 
 
 White House, the, 335, 346, 347, 363, 
 
 3 6 5 
 
 Wigram, pupil 64 
 Williams, John 83, 173, 174 
 Williamson, pupil 49 
 Williamstown Observatory 252 
 Wilson, Prof. 196 
 Winchester 145 
 Winds (see Meteorology) 
 Winning 27, 30 
 Wood, Sir Charles 109, 130 135, 222, 
 
 227 
 
 Wood, Dr 47 
 
 Woodbridge, Suffolk 358, 362 
 Woodhouse, Prof. 29, 40, 47, 48, 72, 
 
 77, 79 
 
 Woolwich Academy (see Examinations) 
 Wordsworth, Dr, Master of Trin. Coll. 
 
 3 1 ' 3 6 , 53, 6l 
 
 Wordsworth, poet 64, 76, 149, 150 
 Wrede, Baron 210 
 Wynter, Vice-Chancellor, Oxford 157, 
 
 1 66 
 
 Yolland, Col. 154, 202 
 York Cathedral 50, 147, 149, 176 
 Young, Dr 55, 67, 69, 74, 77, 79, 82, 
 
 85,87 
 
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