*THE ENGINEER" SERIES 
 
 WHAT INDUSTRY OWES 
 TO CHEMICAL SCIENCE 
 
 RICHARD B.PILCHER 
 
 AND 
 
 FRANK BUTLER-JONES 
 
 WITH AN INTRODUCTION BY 
 SIR GEORGE BEILBY 
 
" THE ENGINEER " SERIES. 
 
 WHAT INDUSTRY OWES 
 TO CHEMICAL SCIENCE. 
 
 By 
 
 RICHARD B. PILCHER, 
 
 Registrar and Secretary of the Institute of 
 Chemistry of Great Britain and Ireland; 
 
 AND 
 
 FRANK BUTLER-JONES, B.A. (Cantab.), A.I.C., 
 
 Assistant, Laboratory of the Department of 
 Explosives Supplies, Ministry of Munitions. 
 
 With an Introduction by 
 Sir GEORGE BEILBY, LL.D., F.R.S., 
 
 Past President of the Inttitute of Chemistry 
 and of the Society of Cktmieal Industry. 
 
 New York : 
 
 D. VAN NOSTRAND COMPANY, 
 25, Park Place. 
 
 1918. 
 
PRINTED IN GREAT BRITAIN. 
 
CONTENTS. 
 
 INTRODUCTION vii 
 
 PREFACE xiii 
 
 Chap. I. MINERALS AND METALS 1 
 
 II. HEAVY CHEMICALS AND ALKALI 22 
 
 III. COAL AND COAL GAS 34 
 
 IV. DYES, EXPLOSIVES, AND CELLULOSE ... 41 
 V. OILS, FATS, AND WAXES 53 
 
 VI. LEATHER 59 
 
 VII. RUBBER 63 
 
 VIII. MORTAR AND CEMENT 65 
 
 IX. REFRACTORY MATERIALS 68 
 
 X. GLASS AND ENAMELS 70 
 
 XI. POTTERY AND PORCELAIN 77 
 
 XII. CHEMICAL PRODUCTS' 80 
 
 XIII. PHOTOGRAPHY 90 
 
 XIV. AGRICULTURE AND FOOD 95 
 
 XV. BREWING 104 
 
 XVI. ALCOHOL, WINES AND SPIRITS 109 
 
 XVII. TOBACCO, INKS, PENCILS, ETC. ... ... 115 
 
 XVIII. GASES 122 
 
 XIX. GOVERNMENT CHEMISTRY 133 
 
 CONCLUSION 138 
 
 BIBLIOGRAPHY 141 
 
 INDEX 144 
 
 387485 
 
INTRODUCTION. 
 
 AMIDST the flood of opinions and advice on the 
 relations of science to education and industrial 
 prosperity with which we have been deluged 
 during the past two or three years, we may turn 
 with welcome relief to the unembellished records 
 of work done and of ends accomplished which the 
 authors have here presented for our enlightenment 
 and encouragement. The majority among us 
 stood much in need of enlightenment on this 
 subject, and many of us will feel grateful for the 
 encouragement which is to he derived from these 
 records of past achievement. These records supply 
 a complete answer to a question with which most 
 chemists have had to deal at one time or another 
 during their career : what is the place of the 
 chemist in practical life, and what part has he 
 taken in industrial and social development ? 
 
 The engineer ministers to the comfort and 
 convenience of the community in ways which 
 can hardly escape the notice even of the man in 
 the street. The Forth Bridge, the ocean grey- 
 hound, the motor car and the aeroplane are at 
 once recognised as the fruits of his skill and energy, 
 
viii WHAT INDUSTRY OWES 
 
 but for the most part, the work of the chemist is 
 inobvious, and is little, if at all, understood. But 
 the chemist and his half-brother, the metallurgist, 
 have all the time been hard at work in the back- 
 ground, helping to provide the engineer with 
 metals and other ^materials of new and improved 
 qualities, without which he could not have produced 
 the machines and structures which represent the 
 triumphs of his art. 
 
 In many other directions chemistry has been 
 the handmaid of arts and crafts, which make 
 their appeal to the public on far other grounds 
 than those of the chemical and other scientific 
 help they have laid under contribution. 
 
 But chemistry also has its own triumphs, and 
 those who will take the trouble to study this work 
 will be rewarded with visions of achievement in 
 this field which they had not hitherto dreamt of. 
 
 These records ought to prove stimulating and 
 suggestive to those whose sons and daughters 
 have not yet selected a calling or profession. The 
 place of chemistry in the national life has been 
 far more important than the majority of educated 
 people have imagined, and this place bids fair to 
 become of vastly increased importance in the near 
 future. The special message for parents and 
 teachers is, therefore, that trained chemists will, 
 in the near future, be in increased demand for 
 industrial and official positions. 
 
TO CHEMICAL SCIENCE ix 
 
 For the responsible teachers of chemistry there 
 are other messages also, if they care to seek for 
 them ; for from these records of achievement 
 much may be learned as to the actual needs of 
 industry on its scientific side, and as to the types 
 of workers who will have to be trained if these 
 needs are to be properly met. 
 
 The great body of teachers of science on the one 
 hand, and the still greater body of manufacturers 
 on the other hand, have been equally at sea as to 
 how (a) the results of scientific discovery, and 
 (6) the young graduates in science who are prepared 
 at our universities and colleges, can best be utilised 
 in industry. Speaking broadly, the teachers of 
 science do not know the needs of industry, either 
 in regard to the nature of the problems which 
 await solution, or to the kinds of trained experts 
 who will be required to take part in the more 
 highly organised industries of the future. Again, 
 speaking broadly, manufacturers and leaders of 
 industry are equally at a loss as to the means 
 whereby scientific discovery, scientific methods and 
 scientifically trained men can be used most 
 effectively in the development of the industries 
 for which they are responsible. 
 
 Fortunately, there are already lines of communi- 
 cation open between these two important bodies, 
 and the hope for the future is that these lines may 
 be broadened out into a common ground on which 
 
WHAT INDUSTRY OWES 
 
 mutual understanding will be reached and where 
 practical schemes of development will be developed. 
 Much can, undoubtedly, be done to improve 
 the training of chemists for practical life. It is in 
 the laboratory that the foundations of this training 
 must be well and truly laid by sound training and 
 ample practice in manipulation and methods. Not 
 only manipulative skill, but resourcefulness and the 
 power of organising routine work ought to be 
 acquired in the laboratory, if the training is on the 
 right lines. On the foundations thus laid, a super- 
 structure of knowledge of physical, mechanical, and 
 chemical laws can be securely built. But a 
 scientific equipment, however sound, is not in 
 itself sufficient ; it is of equal importance that the 
 young chemist throughout his training should be 
 thoroughly imbued with the spirit and aims of the 
 successful leaders of industry. Nothing will so 
 surely awaken in the student an appreciation of 
 practical aims as a wisely directed study of the 
 achievements of science in industry. The present 
 work will supply teachers of chemistry with 
 abundant material for the purposes of this study. 
 This study ought not, however, to displace the 
 parallel study of the steps by which chemical 
 theory has been evolved by the deep insight and 
 the patient observation and experiment of the 
 great leaders in chemical science. It ought to be 
 made clear to the student that, though in one sense 
 
TO CHEMICAL SCIENCE 
 
 the two aims, the attainment of knowledge for its 
 own sake, and its attainment as a means to practical 
 ends, are at opposite poles, yet that there is no 
 real antagonism between them, each is com- 
 plementary to the other. There are intellectual 
 triumphs to be won in the application of science 
 as well as in its pursuit for its own sake. 
 
 The deeper and more prolonged search into the 
 phenomena and laws of Nature must, of necessity, 
 be left to those who by natural endowment and by 
 opportunity can pursue this search apart from 
 the distractions of the work-a-day world. The 
 workers on the applications of science may well 
 realise their debt to these seekers after knowledge, 
 for the seeds of achievement on the practical side 
 must, in many cases, be planted and watered under 
 their fostering care. 
 
 During the past three years the scientific 
 developments of modern warfare have been the 
 means of bringing the workers in pure and in 
 applied science into touch to an extent which 
 would have appeared almost impossible in pre-war 
 times. There are encouraging evidences that this 
 new co-operation has been appreciated on both 
 sides, and that a return to the former condition of 
 isolation would be regarded as most unfortunate. 
 
 The authors have wisely disclaimed any attempt 
 in this work to present the extraordinary wealth of 
 material at their disposal in anything like its true 
 
xii WHAT INDUSTRY OWES 
 
 proportions and perspective. The precious stones 
 in the necklace have been strung together rather 
 with an eye to their collective preservation than 
 to their artistic effect as a whole. Apart from the 
 reasons for this, which the authors themselves 
 have given, I am inclined to think that for the 
 serious purpose they had in view, the method has 
 much to commend it. The central object was not 
 to present a pleasing and finished literary work 
 which would gently stimulate the imagination of 
 the general reader, but to set forth in their bare 
 simplicity the broad facts of achievement, leaving 
 each case to make its own appeal. 
 
 In conclusion, I would express the hope that 
 this work will not only be widely read by the 
 general public, but that it will be cordially welcomed 
 by those who are most deeply concerned in the 
 future of British industry. 
 
 GEORGE BEILBY. 
 
TO CHEMICAL SCIENCE xiii 
 
 PREFACE. 
 
 IN recent times, and especially during the war, 
 a great deal has been written and said on the 
 benefits derived from the applications of science 
 to industry ; the subject has been discussed in the 
 technical and daily Press, and in monographs 
 devoted to particular industries ; but, for the most 
 part, it has been dealt with in the abstract or with 
 very limited reference to the actual results achieved. 
 
 The contents of this volume appeared as a 
 series of articles published in The Engineer during 
 the seven months December, 1916, to July, 1917, 
 inclusive, under the title of " What Industry Owes 
 to Science." The articles were not intended to 
 embrace subjects of common knowledge to the 
 engineer, in which the influence of physical and 
 mechanical science would have claimed greater 
 attention, but dealt mainly with chemical science. 
 For that reason the title of the work has been 
 modified ; the text, however, remains piactically 
 the same. 
 
 The object was to take each industry in turn, 
 and to show by examples how science had 
 advanced the methods and processes of production 
 
xiv WHAT INDUSTRY OWES 
 
 and had laid the foundation for the establishment 
 of new manufactures. 
 
 The work covers a survey of many important 
 industries, presented in such a manner that the 
 substance is not altogether out of the depth nor 
 beyond the interest of the educated public. We 
 hope that it may be especially useful to students of 
 chemistry and engineering, as affording them an 
 indication of the vast field open to them in their 
 professional careers, work in which it may be 
 anticipated that there will be increasing activity 
 and boundless scope in the near future ; and that 
 it will find a place in the offices of men of business 
 in many branches of commerce, and of public 
 companies concerned with productive industries, 
 as well as in the libraries of Chambers of Commerce 
 and Trade Associations. 
 
 A bibliography is provided, including many 
 useful books referred to during the preparation 
 of the work. 
 
 The authors desire to express their deep indebted- 
 ness to Sir George Beilby for his kindness in 
 contributing an introduction, which they feel has 
 very greatly enhanced the value of the volume. 
 
 R. B.P. 
 F. B.-J. 
 London, 1917. 
 
TO CHEMICAL 
 
 WHAT INDUSTRY OWES TO 
 CHEMICAL SCIENCE. 
 
 CHAPTER I. 
 MINERALS AND METALS. 
 
 WE have heard a good deal lately of our neglect 
 of science, particularly of applied science and we 
 are prepared to admit that this country has been 
 behind other countries in realising the importance of 
 scientific principles in industry. The fact remains, 
 however, that though we have been so remiss, we can- 
 not have ignored science entirely, or surely the 
 position of our industries those that are left to us 
 to-day would not be what it is. Instead of pursuing 
 the subject in the abstract, we propose in a few brief 
 chapters to deal with accomplished facts ; to show by 
 illustrative examples the extraordinary developments 
 directly attributable to scientific thought and method 
 and the benefits derived therefrom by the community. 
 The whole art of engineering is based on physical 
 and mechanical science, and the materials employed 
 in this art are dependent in some degree on the 
 science of chemistry. This country has never lacked 
 engineers of the first order, and, therefore, if we may 
 judge by their works, we must conclude that their 
 science has been as truly founded as their structures, 
 and their materials must likewise have been suitable 
 for their purpose. Clearly, then, we have not been 
 lacking the aid of physicists, mathematicians, and 
 chemists in the art of engineering and all that the 
 term denotes. The materials of construction cannot 
 be used intelligently unless the engineer has a proper 
 
'WHAT INDUSTRY OWES 
 
 knowledge of their physical powers of withstanding 
 stress and strain, as well as of their chemical proper- 
 ties, including their internal structure and power of 
 resistance to air, fire, water, and other agencies. 
 
 The subject is so vast and its ramifications so diverse 
 that it is difficult to deal with it without being drawn 
 into the production of a text-book, but we will 
 endeavour to keep to the principal aim of showing the 
 influence of science in industrial progress. 
 
 Our methods of utilising science may be wrong, 
 and there may be room for great improvement, 
 but the impression is gaining ground that in the 
 habit of decrying ourselves and our doings we have 
 overshot the mark. We have used science more 
 than we realise, but have not talked about it as much 
 as some other people. We know, for instance, 
 several Sheffield steel firms who employ thirty to forty 
 chemists and are in constant touch with the most 
 experienced men of science interested in this branch 
 of industry. We know also that both in the direc- 
 torate and in the control of the actual processes 
 of manufacture in the works the industry is coming 
 more and more under the personal supervision of 
 scientific men, that new laboratories are being 
 equipped, and that science in the steel industry is 
 now very much to the fore. 
 
 STEEL. 
 
 German delegates to the meeting of the Iron and 
 Steel Institute held at Sheffield in 1905, freely 
 admitted that Germany had much to learn from that 
 centre and no doubt derived benefit from the hos- 
 pitality then extended to them. The reputation of 
 Sheffield in steel production dates from 1740, 
 when Huntsman discovered the process of casting 
 completely fused rnetal from crucibles. Sixty 
 years ago steel was obtained by decarburising pig 
 iron to malleable iron in a puddling furnace and 
 subsequently introducing the requisite amount of 
 carbon by the cementation process. These operations 
 were protracted, required exhausting labour, and 
 involved the use of large and expensive furnaces 
 
TO CHEMICAL SCIENCE 3 
 
 subjected to considerable wear and tear and consuming 
 large quantities of fuel. 
 
 In 1856, Bessemer a scientific man as the result 
 of experiments deliberately directed to a definite 
 object, introduced his process for *' The Preparation 
 of Steel without Fuel." He found that by forcing 
 a blast of atmospheric air through molten cast iron, 
 contained in a suitable vessel lined with ganister, 
 a siliceous material, the oxidisable impurities in the 
 iron could be removed without the external applica- 
 tion of heat, since the heat produced by oxidation 
 was sufficient to keep the mass in a molten state. 
 Manual or mechanical stirring was unnecessary. The 
 pig was melted in a cupola, and transferred to a mixer 
 of up to 600 tons capacity. From the mixer a charge 
 was conveyed by a ladle to the converter, the latter 
 being swung into position after the " blow " had been 
 started. In twenty minutes the operation was 
 completed ; the blast was stopped for a few seconds 
 while a workman threw in from a shovel sufficient 
 spiegel or ferro-manganese to introduce the proper 
 proportions of carbon ; the blast was started again 
 for a short time to mix the metal and the charge was 
 immediately poured into moulds. 
 
 Contrast the rapidity and simplicity of this method 
 with the time and labour expended in the other. 
 Cementation alone required seven to ten days ; the 
 equivalent effect, after Bessemerisation, occupies only 
 the time required to add the spiegel and re -mix the 
 charge. The fuel expended is only that used in the 
 cupolas, and even that is obviated in some cases where 
 the constancy of grade of pig from the blast-furnaces 
 can be relied on, when the pig is taken direct from the 
 blast-furnace to the converter. 
 
 The original or acid Bessemer process had, however, 
 two disadvantages: (1) phosphorus and sulphur 
 could not be removed owing to the reduction of their 
 oxides by iron and, therefore, only special " Bessemer 
 pigs," free from phosphorus and very low in sulphur, 
 could be used ; (2) the ingots produced contained 
 blow-holes. Science overcame the first of these 
 disadvantages. In 1879 Thomas and Gilchrist found 
 
 B 
 
WHAT INDUSTRY OWES 
 
 that by lining a converter with burnt dolomite or 
 magnesite, instead of ganister, and by adding a 
 quantity of lime to the charge, the whole of the 
 phosphorus and some of the sulphur could be removed. 
 This was the result not only of scientific methods 
 of research but of the direct application of a scientific 
 principle, viz., that of using a basic lining and adding 
 lime, a basic material, to retain the acidic substances 
 produced by the oxidation of phosphorus and sulphur. 
 The second problem, however, was solved by the 
 empirical discovery that the addition of a very small 
 quantity 5 to 8 oz. per ton of aluminium to the 
 molten metal minimised the formation of blow -holes. 
 The only important rival to the Bessemer method is 
 the open-hearth process, perfected about twelve years 
 later by Sir William Siemens and his brother both 
 scientific men. After great initial difficulties, they 
 succeeded in decarburising iron without contact with 
 solid fuel. In this process an exceedingly high 
 temperature is produced in an oxidising atmosphere 
 by the combustion of a mixture of producer gas and 
 air fed into the furnace. Changes take place of the 
 same character as in the Bessemer process. Both 
 acid and basic hearths are used, and the principle of 
 regenerative heating is utilised. 
 
 To Dr. Sorby, of Sheffield, we owe the introduction 
 of metallography, and in this connection the names 
 of Osmond, Martens, Stead, Roberts-Austen, Sauveur, 
 and Le Chatelier, all men of science, must be remem- 
 bered. Up to the present day, and for some years past, 
 the miscroscopic examination of the etched surfaces of 
 metal has been common practice in steel works labora- 
 tories. Researches on the cause of recalescence, com- 
 bined with the intimate knowledge of the structure of 
 steels afforded by miscroscopic examination, have 
 placed in the clear light the equilibrium relations of 
 iron and carbon, and have thus changed rule-of -thumb 
 experience into sound scientific principle. Our views 
 on the physical and chemical nature of these equili- 
 brium relations have been changed by the progress of 
 research. Explanation by means of the solution theory 
 has replaced that based on the theory of the allotropy 
 
TO CHEMICAL SCIENCE 
 
 of iron, and our knowledge of the subject is thus be- 
 coming more definitely established. To be able to ex- 
 plain a phenomenon is second only to knowing that 
 the phenomenon will occur. Whereas rule -of -thumb 
 or empirical discoveries may occasionally give us good 
 results, science, organised knowledge, enables us to 
 proceed on definite lines. 
 
 The discovery of rarer metals has led to the manu- 
 facture of many varieties of steel, including alloys of 
 special hardness. The properties of special steels 
 and their behaviour under varying conditions, the 
 bearing of the character of their internal structure 
 and similar questions have formed the basis of 
 numerous researches which have rendered the in- 
 dustry in an increasing degree more exact and 
 scientific. The researches of Sir Robert Hadfield 
 have resulted in supplying us with special steels 
 differing from ordinary steels, through the addition 
 of various elements other than those commonly 
 present, whereby they acquire properties of enhanced 
 hardness, toughness, elasticity, &c. 
 
 Thus, by adding 7 to 20 per cent, of manganese we 
 ensure great strength and toughness, the well-known 
 Hadfield steel ordinarily containing about 13' per cent, 
 of manganese and 1 per cent, of carbon ; the addition 
 of about 3 per cent, of nickel and 0.2 per cent, carbon 
 gives us a steel of tensile strength and elasticity suit- 
 able for the manufacture of gun barrels ; and the 
 addition of 2 to 3 per cent, of chromium with about 
 1 per cent, of combined carbon gives a remarkable 
 steel which, when hardened and tempered, is employed 
 in the manufacture of locomotive tires and springs, 
 armour plates, armour-piercing projectiles, and certain 
 qualities of files. Similarly, the introduction of 
 titanium, molybdenum, tungsten, aluminium, vana- 
 dium, and boron gives varying effects now easily 
 obtainable by the scientific steel maker. 
 
 These examples serve to illustrate clearly the 
 advantages gained by the application of scientific 
 knowledge in the production of one of our chief 
 materials ; but the function of the chemists in a steel 
 works or any works is not confined to devising pro- 
 
 B 2 
 
6 WHAT INDUSTRY OWES 
 
 cesses or producing varieties of the products. They 
 are concerned with problems of many kinds, and 
 among these the question of fuel and fuel economy 
 both in raising power and in smelting operations are 
 of primary importance. Science determines the 
 suitability and value of the coal employed. Tests are 
 made to determine the calorific power and to estimate 
 the sulphur, ash, and the volatile matter, including 
 moisture, all important factors from the point of view 
 of economy. The manufacturer who ignores these 
 questions must suffer through the employment of coal 
 containing sulphur which attacks his fire-boxes, and 
 the purchase of water and useless mineral matter. 
 Next, the treatment of boiler-feed water where the 
 supply is not naturally soft must not be neglected, or 
 the accumulation of scale will result in waste of heat, 
 inefficient working, and other deplorable conditions. 
 The method of water softening, by the addition of 
 lime, was established by Dr. Thomas Clark, Professor 
 of Chemistry at Aberdeen University, from 1833-39, 
 and its importance in every industry involving the use 
 of boilers, or requiring the use of soft water, must 
 have been and still is inestimable. 
 
 NON-FERROUS METALS. 
 
 Mining and metallurgical industries are essentially 
 scientific, calling for the services of chemists (1) on 
 the mines, to examine ores, to advise on their concen- 
 tration and generally to specify the methods to be 
 adopted for the extraction of metals, and (2) in the 
 actual working of the metal. 
 
 The production of non-ferrous metals, such as 
 copper, lead, zinc and aluminium, needs the help of 
 trained technologists whose labours are constantly 
 directed to the discovery of improved processes and of 
 new varieties of alloys adapted to special purposes, 
 particularly those demanded by the trend of engineer- 
 ing development. 
 
 In surveying the history of non-ferrous metallurgy, 
 the most striking feature is the extent of comparatively 
 recent scientific advancement. In many cases the 
 methods of treating ores to obtain crude metal 
 
TO CHEMICAL SCIENCE 
 
 remain fundamentally the same as when they were 
 originally discovered for the most part empirically ; 
 but they have been explained, modified, and improved 
 by science ; while in other cases, new and better 
 methods, due solely to science, have been substituted 
 for old ones. 
 
 The Separation of Minerals. The ores of heavy 
 metals are frequently of such low grade that the 
 metal cannot be won economically. Thousands 
 of tons of valuable minerals would still remain 
 unworked except for the scientific methods of con- 
 centration now employed. An ore containing only 
 one per cent, of tin will repay treatment. 
 It cannot be smelted, but a complex process 
 of table washing, roasting, and washing again con- 
 centrates it to 60 to 70 per cent, ready for the 
 smelter. Low grade sulphide ores and graphite 
 ores are concentrated by one or other of various 
 methods of oil separation and flotation which afford 
 interesting examples of discovery originated in 
 empiricism, developed by chance discovery and 
 mechanical ingenuity and further improved by the 
 direct application of scientific thought, whereby their 
 utility has become widely extended so as to effect 
 invaluable economies in the mineral industries. 
 Although various theories have been advanced to 
 explain the phenomena of flotation, the true mechan- 
 ism remains as yet obscure. It is instructive to 
 follow the stages of the advances made in this direc- 
 tion, and to indicate the present views on the subject. 
 
 In 1886 Carrie J. Everson found that sulphide 
 mineral particles could be separated from the gangue 
 in ores by kneading the finely crushed ore with a paste 
 formed by the action of sulphuric acid on certain 
 oils, e.g., linseed or cotton seed. The oil adhered to 
 the particles of sulphide mineral and bound the whole 
 into a coherent mass. The gangue was then washed 
 away by water. The process was very little used, its 
 application being limited to rich pyritic gold ores, 
 the treatment of which was profitable. 
 
 The next development, patented by Elmore in 1898, 
 was an oil separation process wherein the finely 
 
8 WHAT INDUSTRY OWES 
 
 crushed sulphide ore made into a pulp with water 
 was well mixed with 3 to 6 per cent, of its weight 
 of residuum oil. The oil floated to the top and 
 formed a layer carrying the sulphides, leaving behind 
 the gangue. The top layer was separated by means 
 of a spitzkasten and the oil run into a centifrugal 
 machine containing warm water, where some of the 
 oil was separated to be used over again. The partially 
 de -oiled concentrates were further treated in a smaller 
 centifrugal to effect a further separation of oil, and 
 were then ready for the smelter. In 1901 Elmore 
 patented the use of sulphuric acid in the process, as 
 an aid to the production of cleaner concentrates. 
 The process was not generally adopted because the 
 losses of oil due to entanglement in the gangue pulp 
 were very high. 
 
 The Elmore vacuum method was an outcome of 
 the above. This is an oil flotation process, as distinct 
 from an oil separation process. The pulp of ore and 
 water, mixed with a very small quantity of oil and 
 enough sulphuric acid to make the mixture slightly 
 acid, is exposed to a partial vacuum ; the air 
 dissolved in the water rises up through it in the form 
 of bubbles, floating the oiled sulphides to the top, 
 whence they are drawn off. From a 2 to 3 per cent, 
 copper ore, concentrates of up to 20 per cent, can 
 be produced. 
 
 In 1901 C. V. Potter, working on Broken Hill ore, 
 heated the crushed ore in an acid water pulp. The 
 action of the acid upon carbonates in the ore generated 
 carbonic acid gas, which, rising to the top, carried 
 sulphide mineral with it. In 1902, in connection with 
 this process, G. D. Delprat used salt cake instead of 
 sulphuric acid. 
 
 In 1903 Cattermole, by adding 4 to 6 per cent, 
 of oleic acid to the ore -water pulp and applying slow 
 agitation, caused the sulphide particles to aggregate 
 into large granules with the oil. The gangue which 
 remained in the pulp was then separated by means 
 of an up -cast. The principle of the method was good, 
 but the expense in oil was large. It was in connection 
 with the work on this process, however, that the froth 
 
TO CHEMICAL SCIENCE 9 
 
 flotation process was discovered. By using small quan- 
 tities of oil up to 0. 1 per cent, calculated on the ore, 
 though less generally and churning up the pulp with 
 air by rapid agitation with a special paddle, the oiled 
 sulphide particles are caused to rise to the top as a 
 strong froth which is floated off by a spitzkasten. This 
 process especially has been developed by scientific re- 
 search, and the efficiency and the economy of ore con- 
 centration have been thereby greatly improved. Sul- 
 phide ores of zinc, copper, lead, iron, antimony, 
 molybdenum, and of other metals are very efficiently 
 treated. Tin -stone -pyrites table concentrates are 
 separated, the pyrites being floated off ; and graphite 
 is easily concentrated to an exceedingly clean product. 
 The grade of the concentrates is high and the recovery 
 excellent. The use of acid is sometimes necessary 
 to produce clean concentrates, enough being added 
 to ensure an acid reaction in the pulp. Curves can be 
 plotted showing the variations hi grade of concen- 
 trates and recovery with variation in the amounts of 
 oil and acid used. The testing of ores is scientifically 
 carried out in special apparatus. The experimenter 
 not only finds the best method for treating the ore, 
 but also observes and records any peculiarities ex- 
 hibited that may be of use in furthering the aims of 
 the process or may serve to throw light on the 
 ultimate causes of the principles underlying the 
 method. Wood's modification of the above process 
 renders it possible to concentrate certain ores without 
 the use of oil. 
 
 These concentration processes are of comparatively 
 recent invention, and are increasingly applied to the 
 treatment of low grade sulphide ores and the tailings 
 from table concentrations. 
 
 Experiments on the flotation of other minerals, 
 such as native copper, gold, and Scheelite, an ore of 
 tungsten, have met with success, and will probably 
 be greatly developed during the next few years. The 
 flotation of carbonate and other oxidised ores has 
 been attempted with positive results, but this exten- 
 sion also is as yet in the experimental stage. The 
 general opinion of men of science at the present day 
 
10 WHAT INDUSTRY OWES 
 
 is that flotation, is an effect of surface tension, though 
 some favour the view that the mineral particles must 
 also carry an electric charge. The ultimate causes 
 can only be established by further research. 
 
 In dealing with the separation of minerals we should 
 mention also the important work of electrical and 
 mechanical engineers, to whom much credit is due for 
 the invention of magnetic separators. Many ores 
 containing magnetic minerals are now efficiently 
 treated by these machines, involving both wet and dry 
 methods. As instances may be taken the magnetic 
 concentration of magnetite ores, and the separation 
 of this mineral from pyrites. Magnetic separation 
 has also been applied in the treatment of monazite 
 sands for the concentration of thorium, to which we 
 will refer later. 
 
 Copper. Scientific knowledge has come to the aid 
 of the copper smelter and refiner in various ways. The 
 introduction of water -jacketed blast furnaces such 
 as are used in lead smelting in the fusion for regulus, 
 has reduced wear and tear to the minimum. These 
 furnaces are made of iron and are double walled, with 
 water circulating through the space between the 
 walls, producing a cooling effect inside the furnace in 
 the immediate vicinity of the wall. The result is 
 that some of the molten slag solidifies on the wall, 
 forming a protective coating which is not further 
 attacked, since the liquid does not corrode it, and 
 thus the iron walls of the furnace scarcely come into 
 contact with the liquid. 
 
 A method of smelting pyritic copper, silver, or gold 
 ores by the heat of oxidation of the pyrites, without 
 the aid of any other fuel was introduced as recently 
 as 1905 ; in actual practice, however, up to 5 per cent, 
 of carbonaceous fuel is now added. Water-jacketed 
 blast furnaces are used, and air pre-heated in some 
 cases is liberally supplied through a large number 
 of tuyeres. 
 
 Copper intended for use as an electrical conductor 
 must be of high quality, the presence of very small 
 quantities of certain other bodies causing a marked 
 diminution in its efficiency. The necessary degree of 
 
TO CHEMICAL SCIENCE 11 
 
 purity can now easily be obtained by the methods of 
 electrolytic refining. A thin sheet of electrolytic 
 copper forms the cathode, a slab of blister copper 
 the anode, and the electrolyte is an acidified solution 
 of copper sulphate. 
 
 Pure copper is deposited on the cathode, the anode 
 being gradually dissolved. Impurities in the copper, 
 such as iron, zinc, nickel, &c., of which the sulphates 
 are soluble, are allowed to accumulate in the solution 
 until their quantity renders the liquor inconvenient 
 to deal with. At this stage the copper in the liquor 
 is precipitated with metallic iron and fresh solution 
 substituted. Other metals present, such as platinum, 
 gold, silver, lead, and arsenic, form a fine mud in the 
 bath, and this mud is afterwards treated for recovery 
 of the precious metals. Thus, by this scientific 
 method, not only is copper obtained in a very pure 
 state, but the gold, silver, and platinum also can be 
 extracted profitably. 
 
 Lead. A remarkable instance of the application of 
 pure science to the solution of a technical problem is 
 provided in the methods employed in the desilverisa- 
 tion of lead by the Pattinson and the Parkes methods. 
 Before 1833 the only available process was cupellation, 
 and this could only be effected economically if the lead 
 contained 8 oz. per ton or more of silver. Therefore 
 much silver remained in the lead, of which, in the 
 aggregate, large quantities contained less than this 
 amount. The method patented by Hugh Lee 
 Pattinson in 1833 depended on the fact that when 
 a solution is partially frozen some of the solvent 
 separates in the solid form, leaving a solution richer 
 in the dissolved substance. For instance, when salt 
 water is frozen, pure ice separates and the remaining 
 solution Is stronger in salt. Molten lead containing 
 silver may be regarded as a solution of silver in lead, 
 and if this solution is allowed to solidify partially, 
 almost pure lead separates out in crystals. Two 
 methods are adopted, that of thirds and that of 
 eighths. Usually, sixteen kettles, lined with lime to 
 prevent attack by litharge and holding about 12 tons 
 each, are employed. For lead comparatively rich in 
 
12 WHAT INDUSTRY OWES 
 
 silver, two-thirds of the contents of each pot are 
 removed as lead crystals ; and for lead which is 
 poorer in silver, seven-eighths of the contents is 
 removed from each pot. In the latter case fewer 
 pots are required. By these means, respectively, 
 starting from a lead containing up to 3 oz. of silver 
 per ton, a silvery lead containing 700 oz. per ton, 
 and a " pure " lead containing only oz. to oz. of 
 silver per ton can be obtained. The process in each 
 case is stopped when the silver reaches about 700 oz. 
 per ton, as this is approaching the eutectic.* A 
 modification of the method nas been introduced 
 whereby the lead is cooled more quickly by blowing 
 in steam and spraying the top of the lead with cold 
 water, the rich silvery lead being poured off from the 
 crystals instead of the latter being baled out. 
 
 The silvery lead obtained by either process is 
 cupelled on a hearth made partially of bone ash, 
 which absorbs most of the lead oxide. Some of the 
 litharge produced is blown over the side of the cupel 
 by the blast of air, and is used in the manufacture of 
 paint. 
 
 The Parkes process depends upon the fact that 
 silver is much more soluble in zinc than it is in lead, 
 whilst lead and zinc are mutually soluble only to a 
 small extent. A saturated solution of zinc in lead 
 contains only about 1 per cent, of zinc whilst a 
 saturated solution of lead in zinc contains 2 to 3 per 
 cent, of lead. If, therefore, molten argentiferous lead 
 is stirred up with molten zinc the latter extracts most 
 of the silver from the lead and when the stirring is 
 discontinued rises to the top, forming a separate layer. 
 An exactly parallel operation frequently used in the 
 laboratory is the method of extraction by ether. 
 On shaking ether and water together each dissolves a 
 little of the other. When the shaking is stopped the 
 liquids separate into two layers, the ether being the 
 uppermost. Suppose we are dealing with the aqueous 
 solution of a substance that is more soluble in ether 
 than in water, and that the solution in water is 
 inconvenient to work with, the substance can be 
 
 * See note on p. 21. 
 
TO CHEMICAL SCIENCE 13 
 
 almost completely removed as a solution in ether by 
 shaking the solution repeatedly with small quantities 
 of ether, which can then be removed by distillation. 
 
 In practice, the work lead is purified by remelting, 
 to effect the removal of copper, arsenic, antimony, &c. 
 The lead, so far purified, is then melted in a pot 
 and heated to about 500 deg. C., lumps of zinc are 
 added and the liquid is well stirred with iron paddles. 
 The quantity of zinc added depends on the richness 
 of the lead in silver, but in any case is very small and 
 rarely exceeds 2 per cent, of the weight of the lead. 
 When the agitation is stopped, the liquid is allowed to 
 cool and a crust of zinc containing the silver solidifies 
 on top of the still molten lead, is removed by ladles 
 and liquated to separate some of the zinc. The 
 remainder of the zinc -silver mixture is then transferred 
 to graphite retorts and the zinc is distilled off. It is 
 found to be advantageous in extraction by zinc as in 
 the case of ether to add the zinc in three instalments, 
 and not all at once. When the lead contains gold, 
 about one-tenth of the zinc is put in at first, when the 
 scum of zinc separated contains all the gold. The 
 silver is then extracted by continuing the process. 
 The remaining lead contains about 1 per cent, of 
 zinc, which is removed by blowing air and steam 
 through the molten metal, the zinc being blown away 
 as oxide, leaving the lead in a very pure state. The 
 Parkes process, now used extensively, has been 
 rendered more efficient by the recent discovery that 
 graphite retorts can be used for the distillation of the 
 zinc. 
 
 These processes for desilverisation not only yield 
 valuable quantities of silver but also produce lead 
 in a high state of purity. In fact, lead as now pro- 
 duced is one of the purest of the commercial metals. 
 It would probably not be so if no precious metal 
 could be extracted from it, because in order to win 
 the silver all other impurities must also be removed. 
 Whereas work lead is hard, pure lead is soft and can 
 be easily manipulated, purity being, moreover, very 
 important in the starting material for the manufac- 
 ture of white lead for making paint. 
 
14 WHAT INDUSTRY OWES 
 
 Nickel was discovered by Cronstedt in 1750- 
 During recent years it has assumed an important 
 position in the civilised world. It is malleable, 
 ductile, hard, takes a high polish, and is very 
 resistant to atmospheric oxidation. To these 
 valuable properties nickel owes its use in the electro- 
 plating of small iron and steel articles to prevent 
 rusting, in the manufacture of rifle bullets, which are 
 covered with a layer of nickel to give a hard clean 
 surface that will not foul the barrel, and also in the 
 preparation of nickel steels and of certain alloys 
 with copper and zinc, such as nickel silver, which 
 are used in the manufacture of forks and spools, 
 ornamental articles, wire, medals, and coins. Nickel 
 is also used in the finely divided state as a catalyst, 
 in the hydrogenation of certain oils and fats. By the 
 action of hydrogen in the presence of finely divided 
 nickel, liquid oils such as fish oil, linseed oil, olive oil, 
 can be " hardened " into solid fats suitable for the 
 starting materials in the manufacture of foodstuffs, 
 candles, and soap. For these purposes the nickel 
 used must be very pure. The older methods of pro- 
 duction were difficult and expensive, but in 1895 
 Ludwig Mond introduced a method by which the 
 pure metal can be obtained at a comparatively low 
 cost from the matte produced by the first smelting 
 operation. Mond discovered that metallic nickel 
 combines with carbon monoxide when heated to 
 80 deg. C. in an atmosphere of that gas, yielding 
 a volatile compound, nickel carbonyl. The matte is 
 roasted and then reduced at 400 deg. C. by 
 producer gas. The reduced metal is then exposed 
 at 80 deg. C. in a " volatiliser " to the action of 
 carbon monoxide. The gas issuing from the volatiliser 
 containing the nickel carbonyl is passed through 
 vessels heated to 180 deg. C., where the nickel is 
 deposited in the pure state. The carbon monoxide 
 is obtained from flue gases by passing first through 
 boiling potassium carbonate solution and then over 
 hot coke. The carbon monoxide obtained by the 
 decomposition of the nickel carbonyl at 180 deg. C. 
 is also used over again. This brief survey shows how 
 
TO CHEMICAL SCIENCE 15 
 
 Mond's scientific discovery and its exploitation has 
 had its effect on very diverse industries. 
 
 Sodium. Metallic sodium was first obtained by Sir 
 Humphry Davy, in 1807, by the electrolysis of caustic 
 soda, but no attempt was then made to manufacture 
 sodium on the large scale by that process. Up to 1891 
 it was produced by carbon reduction methods. The 
 method of Brunner, improved by Deville, consisted in 
 igniting a mixture of sodium carbonate and charcoal ; 
 but this process was very wasteful and expensive, 
 and the price of sodium was consequently high. 
 In 1886 Castner employed caustic soda instead of 
 sodium carbonate, and this improvement, the outcome 
 of scientific research, effected substantial decrease in 
 the cost of production. In 1891 the old process was 
 entirely abandoned and replaced by Castner's electro- 
 lytic method, founded on Davy's discovery and 
 developed in the laboratory, by which fused caustic 
 soda was electrolysed in an iron vessel under special 
 precautions for even heating and the maintenance of 
 a constant temperature. The method was cleaner 
 and more efficient, and as a result sodium became really 
 a commercial product, thousands of tons being ren- 
 dered available annually for the preparation of sodium 
 cyanide for gold extraction, under the MacArthur- 
 Forrest process for dealing with low grade ores and 
 sand and slime tailings. 
 
 Aluminium so much valued for its lightness, 
 strength, and unalterability in air has a history 
 resembling that of sodium. It was first isolated in the 
 pure state in 1827 by Wohler by fusing the chloride 
 of the metal with potassium in a closed crucible, and 
 again by the same chemist by passing the vapour of 
 aluminium chloride over potassium. In 1854 Bunsen 
 used the method of electrolysis of the fused chloride, 
 and Deville applied the method of Wohler in attempts 
 to manufacture the metal on a large scale using 
 sodium instead of potassium. Samples of Deville's pro- 
 ducts were shown in ingots at the Paris Exhibition of 
 1855, where they occupied a prominent position, care- 
 fully guarded by gendarmes, only a few visitors being 
 allowed to handle the exhibit, which was regarded as 
 
16 WHAT INDUSTRY OWES 
 
 a great curiosity. This was an incentive to further 
 research, with the result that a short time later the 
 large scale manufacture was established at Alais on 
 the Loire. The use of sodium, then itself a costly 
 metal, was only one item in the heavy expense 
 involved. The method held its own for some years, 
 but in 1887 Bernard Freres, of Paris, reverting 
 to the method of Bunsen, founded their electro- 
 lytic process, using a mixture of cryolite and 
 common salt as the electrolyte. Before 1887 
 aluminum was sold at 3 per pound. Now it can be made 
 at very low cost, where power is cheap, to be sold at 
 little more than a shilling per pound. The method 
 whereby a solution of oxide of aluminium in fused 
 cryolite is kept in the molten state, and decomposed, 
 by an electric current, yields a metal of over 99 per 
 cent, purity compared with the' 97 to 98 per cent, 
 metal from the older process. The expenditure of 
 electrical energy is high, and in the light of our 
 present knowledge it appears futile to endea- 
 vour to reduce it. When aluminium is used in 
 the thermite process, an enormous quantity of energy 
 is evolved in the form of heat, producing a very high 
 temperature, the aluminium being converted into the 
 oxide. To win back the metal from the oxide an 
 equal amount of energy has to be put back, thus 
 accounting for the quantity of energy absorbed in 
 the preparation of the metal. 
 
 Magnesium was first isolated by Davy. Ib owes its 
 method of preparation and present-day uses solely to 
 scientific investigation. It is manufactured by a pro- 
 cess similar to that used for aluminium, by the electro- 
 lysis of fused anhydrous carnallite, a double chloride of 
 magnesium and potassium. The " magnalium " 
 alloys of aluminium and magnesium are lighter than 
 the former metal, give very good castings, and are 
 as strong as brass and bronze. The use of magnesium 
 in flashlight photography is well known. 
 
 Molybdenum and Tungsten, like aluminium and 
 magnesium, are children of science. Both are used 
 for making special steels, and tungsten is also formed 
 
TO CHEMICAL SCIENCE 17 
 
 into filaments for incandescent electric lamps, its 
 efficiency in this role being very great. 
 
 Chromium, which was discovered by Vauquelin in 
 1797, and is much used in the manufacture of special 
 steels, has a very high melting point, and on that 
 account cannot be prepared in a fused state by 
 ordinary methods. The metal was isolated by 
 Deville by heating chromium oxide and sugar char- 
 coal in a lime crucible ; and by Wohler by heating 
 the chloride with metallic zinc under a layer of 
 sodium chloride, and subsequently removing the 
 zinc by treatment with nitric acid, the chromium 
 being thereby obtained in the form of a grey powder ; 
 but these and similar methods could not be adopted 
 economically on a commercial scale. In 1893 
 Moissan published the method whereby a mixture 
 of chromium oxide and carbon is heated to the high 
 temperature of the electric furnace, giving a product 
 containing large quantities of carbon from which it 
 can be freed only by difficult and expensive processes. 
 Ferrochrome, however, an alloy of iron containing 60 
 to 70 per cent, of chromium, is manufactured on a 
 large scale by the thermite process. Chromite, an 
 ore of chromium and iron, is finely crushed and well 
 mixed with aluminium dust. The mixture is ignited 
 with the aid of burning magnesium. The aluminium 
 reduces the oxides of iron and chromium with evolu- 
 tion of great heat, and consequent production of a 
 temperature sufficiently high to fuse the ferrochrome, 
 the alloy being thus produced in a compact and 
 homogeneous condition. Chromium metal of over 
 99 . 5 per cent, purity can be obtained by the thermite 
 process, the principal impurities being small quanti- 
 ties of iron and silicon. The thermite process is used 
 when freedom from carbon is desired, that of Moissan 
 being applicable when the presence of a certain 
 quantity of carbon is not objectionable. 
 
 Thorium, discovered by Berzelius in 1828, is 
 interesting scientifically by reason of its radioactivity. 
 It has found no useful application as a metal, but its 
 oxide, thoria, has proved invaluable to the gas 
 industry, being used for the manufacture of incan- 
 
18 WHAT INDUSTRY OWES 
 
 descent mantles, of which the world's production is 
 estimated at over 400,000,000 annually. Thoria, 
 when heated directly in a flame, possesses the property 
 of converting heat energy into light. Research was 
 therefore directed to the utilisation of this property, 
 the evolution of the modern gas mantle being the 
 result of purely scientific investigations, requiring 
 great skill and patience. Not the least difficult pro- 
 blem to be solved was the production of thoria in 
 the necessary state of purity. In the early history 
 of the manufacture of the mantles, the known sources 
 of thoria were not numerous, although the available 
 ores were rich, and presented little difficulty in treat- 
 ment, but the discovery of large deposits of monazite 
 sand in South America stimulated the industry by 
 considerably diminishing the cost of the materials 
 employed. For a time, while the value of the sand 
 remained unrecognised by the States wherein it was 
 found, the sand was shipped to Europe as ballast an 
 illustration of the advantages to be gained from 
 scientific investigation into natural resources. How- 
 ever, that is another story ! Monazite is a complex 
 mineral consisting of the phosphates of thorium and 
 the metals of the rare earths, occurring mixed with 
 other minerals as a sand. To obtain pure thoria 
 from this ore a protracted treatment . is necessary, 
 involving concentration by tables and by magnetic 
 separation, followed by fractional precipitation of 
 the oxides from solution. The thoria appears on the 
 market as nitrate. In the manufacture of mantles 
 a cotton framework, supported on an asbestos collar, 
 is soaked with a solution of the nitrate and dried ; the 
 cotton is burned away, and the resultant oxide is 
 hardened by further heating, and stiffened by dipping 
 into collodion, which in turn is removed by burning 
 when the mantle is placed in position ready for use. 
 It was found that the presence of about one per cent, of 
 cerium oxide in the mantle increased to a maximum 
 the transformation of heat energy into light, whereas 
 a marked diminution of luminosity was observed 
 when the quantity of cerium oxide was increased or 
 diminished. For this reason the equivalent of one 
 
TO CHEMICAL SCIENCE 19 
 
 per cent, of cerium oxide is added to the solution of 
 thorium nitrate. The credit for practically the whole 
 of the scientific work underlying the industry is due 
 to Auer von Welsbach. 
 
 Vanadium, discovered in 1830 by Sefstrom, in the 
 refinery slag of the iron ore of Taberg, in Sweden, is 
 of increasing service to the maker of special steels. 
 In effect . 2 per cent, is equivalent to 3 to 4 per cent, 
 of nickel, and experience tends to show that it imparts 
 to steel the power of resisting changes caused by 
 vibration, a most valuable property from the engi- 
 neer's point of view. It is mainly used as an alloy, 
 ferrovanadium, prepared by the thermite process. 
 It is worthy of note, as affording an instance of the 
 utilisation of " waste," that the mixture of metals 
 obtained by reducing the rare earth oxides forming 
 the residue of monazite after the extraction of thoria 
 is employed, in the place of aluminium, to produce 
 pure vanadium by a method resembling the thermite 
 process. 
 
 THE NOBLE METALS. 
 
 Gold. In the recovery of gold large quantities 
 of metal were previously thrown away in tailings, 
 owing to the fact that amalgamation left a certain 
 amount unextracted from the ore. The Plattner 
 chlorine method and the Mac Arthur -Forrest cyanide 
 process have now rendered the tailing metal 
 available. The Plattner method, which is also used 
 in the treatment of auriferous pyrites, depends on the 
 action of chlorine gas on the roasted ore, the chloride 
 produced being subsequently leached out with water. 
 The gold is then precipitated by treating the solution 
 with some suitable material, such as ferrous sulphate, 
 charcoal, sulphuretted hydrogen, sulphide of iron, or 
 sulphide of copper. The MacArthur-Forrest pro- 
 cess, also founded on the study of the chemical 
 properties of gold, consists in the treatment of the 
 sand or slime tailings from the amalgamation 
 process, or, in some cases, a very low grade ore, 
 with a dilute solution, not more than 0.3 per cent., 
 of potassium or sodium cyanide, and the subsequent 
 
20 WHAT INDUSTRY OWES 
 
 precipitation of the dissolved gold by means of zinc 
 shavings. The zinc is removed by distillation from 
 graphite retorts, or sometimes by dissolution in 
 sulphuric acid, the latter method yielding a somewhat 
 richer bullion. In a method introduced by Tavener, 
 the zinc -gold precipitate is mixed with litharge, saw- 
 dust and assay slags, and melted in a reverberatory, 
 the resultant lead bullion being subsequently cupelled 
 for recovery of the gold. In another method, 
 devised by Siemens and Halske, the gold is precipi- 
 tated from the cyanide solution by electrolysis, using 
 iron anodes and lead cathodes and recovering the 
 gold by cupelling the cathodes. 
 
 In the separation of gold from silver, nitric acid 
 was at one time universally employed, but in 1802 
 D'Arcet utilised the fact, discovered in 1753 by 
 Scheele, that concentrated sulphuric acid was equally 
 suitable for the purpose. This constituted an improve- 
 ment of considerable value, effecting a saving both of 
 cost and time, and it must be remembered that in this 
 connection " time is money," for gold brings interest. 
 The Platinum Group. The metals of the plati- 
 num group are among the most valuable acqui- 
 sitions of civilised man, and their availability is 
 entirely due to chemists, among whom may be 
 mentioned Achard, Janetty, Knight, Wollaston, 
 Deville, and the firm of Johnson, Matthey and Co. 
 Platinum itself is easily worked by the oxy -hydrogen 
 flame method of Hare, modified and improved by 
 Deville and Debray, and is useful for many purposes 
 in which special resistant properties are essential, 
 such as for vessels employed in analytical chemistry, 
 for stills for the concentration of chamber acid, 
 for standard weights and measures, for electrical 
 leads fused into glass, as a catalyst in the contact 
 process for making sulphuric acid, as a photographic 
 medium, and for mounting jewellery. 
 
 Other members of the group are iridium, discovered 
 by Tennant in 1804, used in combination with plati- 
 num in the construction of pyrometers, and as pure 
 metal for tipping gold pens ; osmium, discovered by 
 Descotils in 1803, and by Tennant in 1804, used in the 
 
TO CHEMICAL SCIENCE 21 
 
 preparation of metallic filaments of electric lamps, 
 and combined with iridium for tipping gold pens and 
 for the bearings of the mariner's compass ; palladium 
 discovered by Wollaston in 1803, employed by 
 dentists and jewellers ; and rhodium, discovered by 
 Wollaston in 1804, used in the manufacture of certain 
 forms of chemical apparatus. 
 
 NOTE (p. 12). An alloy is termed eutectic when it is the 
 most fusible of the alloys of two metals, the melting 
 point being lower than that of either of the two 
 metals of which it is composed. On cooling from the 
 molten state it deposits a solid having the same com- 
 position as that of the molten mixture. For example, 
 the melting points of lead and tin are 328 and 232 deg. 
 Cent, respectively, but an alloy of these metals containing 
 31 per cent, of lead melts at 180 deg. Cent., any variation 
 from this composition entailing a rise in the melting point. 
 If an alloy richer in either constituent be slowly cooled, the 
 metal present in excess of the above composition separates 
 in the solid state as cooling progresses, until the composi- 
 tion of the remaining fluid is that of the eutectic, which 
 then separates in the solid state. In the case of alloys of 
 gold and silver there is no eutectic, the melting points 
 rising regularly from that of silver to that of gold. 
 
 c 2 
 
22 WHAT INDUSTRY OWES 
 
 CHAPTER II. 
 HEAVY CHEMICALS AND ALKALI. 
 
 IN reviewing the progress made in chemical 
 industries proper, we are met with such a condition 
 of interdependence that it is impossible to avoid over- 
 lapping of the subjects to be treated. Moreover, 
 the steps made in the improvement and development 
 of processes, and in the evolution of new products, 
 are so numerous that space will not allow of a com- 
 prehensive scheme. Indeed, the library of the Patent- 
 office, one of the best for technological literature, 
 cannot contain all that is due to chemists, nor disclose 
 to which chemists the credit should be given for many 
 important advances. We must, perforce, recognise, 
 however, that science is the basis of all substantial 
 development in the industrial arts, and that the rule 
 of thumb is dead. 
 
 It has often been said that the prosperity of a 
 country might be gauged by its output of sul- 
 phuric acid ; yet it is remarkable how little 
 the man in the street realises the importance of 
 this substance. He has a vague idea that it is 
 the same thing as, or in some way akin to, vitriol, 
 which he knows is destructive to clothing, and is 
 associated with charges of criminal assault wherein 
 some evil-minded wretch has employed it as the 
 agency for disfiguring the features of a fellow-being. 
 If he were told that, even in normal times, the world's 
 output exceeded 5,000,000 tons he would marvel 
 how it is that he never sees, and probably never 
 has seen, the substance. The reason for this is, 
 that the consumer of large quantities of the acid 
 generally finds it convenient and economical to make 
 it himself. Thus, although large quantities are 
 produced and consumed there is only a comparatively 
 
TO CHEMICAL SCIENCE 23 
 
 small quantity on the market. When we come 
 to consider its technical applications we find there 
 is scarcely an industry that does not depend directly 
 or indirectly on its use. It is employed in the 
 manufacture of superphosphate fertiliser, as a solvent 
 for metals for example, in the parting of gold 
 and silver as a constituent of dipping baths for 
 cleansing brass and bronze castings, and is used 
 in the electrolytic refining of copper. Ammonia 
 from the coal -tar and shale oil industries is absorbed 
 in sulphuric acid, the resultant sulphate being exten- 
 sively employed as a fertiliser. (The world's 
 production of ammonium sulphate probably exceeds 
 1,500,000 tons.) The refining of oils, fats, and waxes, 
 and of tar and petroleum products is also carried out 
 with the aid of sulphuric acid, and it is extensively 
 used in the manufacture and sulphonation of dyestuffs. 
 Nitric acid, guncotton and therefore, cordite, collo- 
 dion and celluloid nitroglycerine for dynamite, 
 phenol, picric acid, T.N.T., ether, saccharine, many 
 drugs, liquid glue, alum, persulphates, and a host 
 of other useful substances are produced by processes 
 in which sulphuric acid is an essential factor. It 
 must be remembered, moreover, that many such 
 substances are but the starting materials for the 
 manufacture of other products ; so that regarded 
 as a mediaeval ancestor, sulphuric acid can boast 
 a genealogical tree of no mean order with many 
 a noble family and innumerable progeny. Nor 
 must we forget that not the least important of its uses 
 is in the laboratory, where also many of its relations 
 are to be found among the reagents required by 
 the chemist. Discovered in the fifteenth century 
 by the alchemists, it was made until about 1770 
 by two methods : (i. ) by the distillation of crystallised 
 sulphate of iron prepared by roasting iron pyrites ; 
 and (ii.) by the combustion of sulphur in a bell jar 
 over water. Of these methods, the first survived 
 until recently, being the only method available 
 for making fuming acid, the second being the fore- 
 runner of the modern lead chamber process. Both 
 are attributed to Basil Valentine (15th century), 
 
24 WHAT INDUSTRY OWES 
 
 who next discovered that by the addition of antimony 
 sulphide and nitre, the yield could be substantially 
 increased. Up to about the middle of the eighteenth 
 century the principal workers at the problem had 
 been alchemists monks and others the pioneers 
 of modern science ; and the only process that could 
 be called a manufacture was that with sulphate of 
 iron as starting material. At about that time, 
 however, two French chemists, Lefevre and Lemery, 
 produced a method, used on a small manufacturing 
 scale, wherein a mixture of sulphur and nitre, without 
 antimony sulphide, was burned under a bell-jar 
 over water. About 1770 Dr. Roebuck, of Birmingham, 
 first employed lead chambers containing water, 
 instead of glass bell- jars, thus considerably enlarging 
 the scale of operations. The procedure was the same 
 as in the bell-jar method. The floor of the lead 
 chamber was covered with a few inches of water, and 
 a kind of stand in the middle of the floor carried the 
 charge of sulphur and nitre. The charge was ignited 
 aid the door was immediately closed and luted 
 securely. The operations of charging, burning, and 
 discharging were repeated until the acid attained 
 the maximum strength compatible with the safety 
 of the lead, when the liquid was drawn off and concen- 
 trated. This was a discontinuous process, but in 
 principle it was the modern continuous method 
 in a primitive state. The transition from the one 
 to the other was gradual, the outcome of much 
 thought and research. A step towards continuity 
 of working was obtained by burning the sulphur 
 in a separate vessel, and leading into the lead chamber 
 the products of combustion, mixed with excess of 
 air, and the fumes evolved on treating nitre with 
 sulphuric acid. Complete continuity and greater 
 speed of working was obtained when Kestner intro- 
 duced the injection of steam into the chamber. 
 The rationale of the process was explained by chemists 
 by the aid of various theories, but a fact of great 
 importance was clearly recognised, viz., that the 
 nitric acid was merely a carrier of the atmospheric 
 oxygen, and needed to be used only in small quantity. 
 
TO CHEMICAL SCIENCE 25 
 
 Next it was found that the spent gas issuing from 
 the chamber gave rise, in contact with atmospheric 
 air, to oxidised nitrogen compounds that could be 
 used again in the chamber. Nitre being the most 
 expensive raw material, many efforts were directed 
 towards the recovery of these gases and their return 
 to the circuit. The most successful of these and 
 the one universally adopted was due to the great 
 French chemist, Gay-Lussac, the friendly rival 
 in many fields of work of our own Sir Humphry 
 Davy. The gases issuing from the chamber were 
 conducted up a tower of lead or stone, packed with 
 coke, down which a slow stream of strong sulphuric 
 acid was caused to trickle. The acid issuing from 
 the foot of the tower contained all the oxides of 
 nitrogen present in the chamber gas. This acid 
 was then conveyed to the top of another tower, 
 invented by Glover, and in penetrating the length 
 of the tower was met by the hot gases from the sulphur 
 burners and deprived of its nitrogen oxides which 
 were returned to the chamber with the ingoing gases, 
 to play again their part in the transformation. The 
 acid drawn from the chamber was concentrated 
 in glass retorts, platinum being afterwards substituted 
 for glass. Although the initial outlay on platinum 
 was very considerable, the loss by breakage was 
 avoided. 
 
 This short history of sulphuric acid manufacture 
 should serve to illustrate how science has been the 
 primary factor in its evolution. The subject of the 
 use of iron pyrites as a source of sulphur will be 
 deferred until we consider the alkali industry. 
 
 We must digress for a moment to refer to another 
 industry in order to indicate the origin of the contact 
 process. About thirty-six years ago, various methods 
 were discovered for the preparation of artificial 
 indigo, and endeavours were made to apply the best 
 of these on a commercial scale to compete with 
 the natural product. The starting material in the 
 most successful processes was naphthalene, at one 
 time regarded by the tar distiller as a nuisance 
 but now recognised as a valuable product. In the 
 
26 WHAT INDUSTRY OWES 
 
 first stage of the synthesis of indigo, naphthalene 
 is converted by oxidation into phthalic acid. This 
 was originally effected by chlorination and subsequent 
 oxidation with nitric acid ; but the process was too 
 expensive for successful application on the large 
 scale. Next the discovery was made that the direct 
 oxidation of naphthalene could easily be effected 
 by fuming sulphuric acid in the presence of mercuric 
 sulphate. At that time, however, the only method 
 of preparing the fuming acid was the Nordhausen 
 process, by heating sulphate of iron, and the product 
 was too highly priced for the prospective indigo 
 manufacturer. Cheap fuming acid was, therefore, 
 a necessity. It had been known to chemists for 
 a half a century or more that sulphuric acid anhydride 
 could be made from sulphur dioxide and oxygen 
 by passing the mixed gases over heated finely divided 
 platinum, and it was found that by absorbing the 
 anhydride in concentrated sulphuric acid the product 
 was the fuming acid. In the laboratory, where 
 the materials employed were comparatively pure, 
 the method left nothing to be desired, but on the 
 works where, for reasons of economy, materials of 
 a crude nature, such as pyrites, had to be used, 
 further obstacles were encountered. The process 
 would go briskly for a time and then it would slow 
 up and finally stop altogether. The platinum had 
 lost its efficiency and the chemists were confronted 
 with another difficulty. They are accustomed to 
 this sort of thing and enjoy it. Indeed, some are 
 almost disappointed when results come too easily 
 and there is a lull in the chase. They found that 
 the platinum had been " poisoned " by arsenic, 
 antimony and mercury from the pyrites ; they there- 
 fore devised the means for washing these oxides 
 out of the sulphur dioxide, and with this purified 
 material their labours were crowned with success. 
 The manufacture of fuming acid and ordinary con- 
 centrated sulphuric acid by the " contact process " 
 is a fast growing industry, and will doubtless in 
 time largely replace the lead chamber process by 
 reason of its efficiency and cleanliness, and the 
 
TO CHEMICAL SCIENCE 27 
 
 compactness of the plant required. Moreover, it 
 is convenient and economical to be able to produce 
 acid of any strength without the expense involved 
 in the concentration necessary in the older process. 
 On account of the diversity of its uses sulphuric 
 acid is required in varying conditions of purity and 
 concentration, from the chamber acid and B.O.V. 
 of commerce to the redistilled acid required in 
 analytical operations. Researches have been con- 
 ducted with a view to the elimination of impurities, 
 and especially of arsenic. The contact process 
 satisfies this requirement, but acid from the chamber 
 process may contain this impurity in considerable 
 quantity. The use of sulphur instead of pyrites 
 results in the production of arsenic free acid, 
 but chamber acid already containing arsenic can 
 be freed from this impurity by precipitating it as 
 sulphide with sulphuretted hydrogen before con- 
 centrating the acid. Another method has been 
 suggested whereby dry hydrogen chloride is passed 
 through strong sulphuric acid heated above 150 deg. 
 Cent., when the arsenic is entirely removed as 
 trichloride, but this has not received extensive 
 application. Both these methods are founded on 
 everyday laboratory experience. 
 
 One hundred and thirty years ago, as a result 
 of the French revolutionary wars, France was cut 
 off from the supply of alkali and an appeal was 
 made to chemists *' to render vain the efforts 
 and hatred of despots," and, incidentally, to win 
 a prize by producing a process for making alkali. 
 This offer resulted, in 1794, in the submission to the 
 Convention of more than a dozen processes, some of 
 which had already been in operation, including that 
 of the apothecary Leblanc, which was accepted. In 
 1814 it was introduced into England, and in 1823 the 
 first works of importance were established near Liver- 
 pool by James Muspratt. In the Leblanc ^process 
 sulphuric acid is employed for the decomposition of 
 common salt. The resulting sulphate is heated with 
 chalk and small coal in a reverberatory furnace ; the 
 mass is lixiviated with cold or tepid water; the 
 
28 WHAT INDUSTRY OWES 
 
 solution is evaporated to dryness and the product 
 is calcined with sawdust in a suitable furnace. The 
 soda-ash or crude sodium carbonate thus obtained 
 is dissolved in hot water, treated with lime, to obtain 
 caustic soda, to be used by the soap and candlemakers, 
 or the solution of the carbonate in water is filtered 
 and crystallised to give washing soda. We have 
 indicated that the substances required for the 
 process were salt, coal, chalk, and sulphuric acid. 
 The first three were to be found in abundance in 
 Nature, but up to that time sulphuric acid was 
 comparatively expensive, and the demand for it 
 was not such as to warrant its extensive manufacture. 
 It was to meet the requirements of the Leblanc 
 process that the output of the acid was enormously 
 increased, and although the process has now been 
 superseded by that of Solvay, as far as carbonate is 
 concerned, and is being replaced by electrolytic 
 methods for making caustic soda, it must not be over- 
 looked that we owe to Leblanc, indirectly, our cheap 
 sulphuric acid, and therefore a thousand and one 
 other cheap commodities. 
 
 To return to the sodium carbonate, we may well 
 ask how many good citizens and washerwomen 
 who use it have any idea that a chemist has anything 
 to do with its production ? Possibly they think 
 it exists naturally in the condition supplied ; more 
 probably still, they think nothing at all about it 
 so long as it serves its purpose. 
 
 If the crystals are re -dissolved in water, filtered 
 and re -crystallised, we have the pure sodium carbonate 
 used in pharmacy. By passing carbonic acid gas 
 into a cold solution of the carbonate, and by placing 
 the crystals in an atmosphere of the gas, we obtain 
 the bi-carbonate which is also employed in pharmacy, 
 and as an ingredient of baking powders. 
 
 The aim of the technologist is to avoid waste 
 of any kind, either of matter or energy, the cost 
 of a product to the consumer being in a great degree 
 dependent on the efficient utilisation both of raw 
 material and of by-products. The alkali industry 
 furnishes many examples. In the Leblanc process, 
 
TO CHEMICAL SCIENCE 29 
 
 among the main products are soda ash, which we have 
 shown is purified to obtain soda crystals, and " alkali 
 waste," of which about 30 per cent, is calcium sulphide 
 containing the sulphur from the original sulphuric 
 acid. The waste was long regarded as useless, but is 
 now treated for the recovery of the sulphur. Many 
 attempts have been made to recover this sulphur in 
 a useful form, but it was only comparatively recently 
 that the Chance-Glaus method was introduced, 
 whereby the alkali waste is made into a paste with 
 water, and acted on by carbonic acid gas lime -kiln 
 gas and furnace gas being used for the purpose. 
 The sulphur of the calcium sulphide is converted 
 thereby into sulphuretted hydrogen, which is mixed 
 with a carefully regulated supply of air and burned 
 in contact with hot ferric oxide in Claus kilns. The 
 hydrogen burns off and the sulphur is deposited 
 in a practically pure state a very valuable product. 
 When, in 1839, an export embargo was placed 
 on Sicilian sulphur, the alkali manufacturers, having 
 to look elsewhere for their supply, found it in iron 
 pyrites. The residue of oxide of iron from the pyrites 
 burners was not used as a source of iron, as it retained 
 enough sulphur to render it unfit for this purpose. 
 The pyrites used also contained a certain amount 
 of copper, averaging 3 per cent., as well as small 
 quantities of gold and silver. Until 1865 these 
 residues were dumped as useless, but in that year 
 Henderson introduced a method whereby the whole 
 of the copper could be recovered by roasting the 
 residues with common salt, lixiviating the mass 
 with water, and precipitating the copper from the 
 resultant solution by means of scrap iron. In 1870, 
 a method was devised by Claudet to recover the gold 
 and silver occurring in the residues. The copper 
 solution formed on lixiviation in Henderson's process 
 contains the gold and silver as chlorides dissolved 
 in the excess of common salt. By Claudet' s method 
 the gold and silver are precipitated by the addition 
 of zinc iodide to this solution, the precipitated 
 iodides being subsequently reduced with metallic 
 zinc in the presence of hydrochloric acid. 
 
30 WHAT INDUSTRY OWES 
 
 Thus by the application of science the revenue 
 of the sulphuric acid and alkali maker increased, 
 the price of his products is lowered, and valuable 
 materials are rescued from the dump. More 
 than 500,000 tons of pyrites are burned annually 
 in England for the sake of the sulphur. The residue 
 from this yields on extraction about 15,000 tons of 
 copper, 400,000 ounces of silver, and 2000 ounces 
 of gold, the final residue being transformed into a 
 valuable source of iron. 
 
 In connection with this subject can be related one 
 of the most interesting episodes in indurstrial history. 
 For some time after the inception of the Leblanc 
 process, the hydrochloric acid produced was allowed 
 to escape into the air, as no use had been found for 
 it. Metal ware was corroded, and vegetable growth 
 destroyed for miles around the works and the nuisance 
 gave rise to much litigation. The obvious remedy 
 was to absorb the noxious gas, and to effect this 
 many of the larger works adopted in 1836 a method 
 devised by Gossage. It was not until 1863, however, 
 that the Alkali Act was passed, enacting that not 
 less than 95 per cent, of the hydrochloric acid gas 
 produced should be absorbed, a regulation rendered 
 more stringent by subsequent legislation. Some idea 
 of the quantity concerned may be gathered from the 
 fact that at that time about 3000 tons of the gas 
 were produced annually in England. To hark 
 back to the earlier days when the makers first laid 
 out capital to provide means for the absorption 
 of the gas, they naturally wondered what return 
 they could get for it. This was forthcoming in the 
 increased demand for chlorine to make bleaching 
 powder to be used for bleaching raw cotton and 
 materials for paper making. Chlorine, set free from 
 the hydrochloric acid by the action of manganese 
 dioxide, was led over slaked lime, and the product 
 was bleaching powder. The same gas passed into 
 cold solutions of caustic soda and potash formed 
 useful bleaching solutions, while if boiling potash was 
 used the product was chlorate of potash, a valuable 
 substance in pyrotechny, in the manufacture of 
 
TO CHEMICAL SCIENCE 31 
 
 certain explosives, and in medicine. The manganese 
 dioxide employed to liberate the chlorine was 
 converted into a useless product, which was a loss 
 to the manufacturer. Science again came to his 
 aid in the discovery of Weldon, that the action of 
 lime and air on the manganese waste resulted in 
 the regeneration of an oxygenated body which might 
 be used in exactly the same way as the original 
 dioxide. Thus, by this process the dioxide acts 
 merely as an agent in liberating the chlorine, and 
 can be used over and over again, atmospheric oxygen 
 being the real factor concerned in the change. 
 
 The Deacon process for the manufacture of chlorine 
 from hydrochloric acid is a scientific method, whereby 
 hydrochloric acid gas and air are passed over hot 
 brick-work impregnated with copper salts. The 
 products are chlorine gas and water, the copper 
 salts acting merely as carriers of oxygen. The only 
 losses are that of the hydrogen of the hydrochloric 
 acid and the oxygen of the air. 
 
 The two processes last considered, together with 
 the lead chamber sulphuric acid process, being among 
 the earliest of this type to be employed, serve to 
 show how the chemist is teaching the manufacturer 
 to use catalytic* and contact agents to effect certain 
 chemical changes more especially those involving 
 oxidation. Such processes are numerous and success- 
 ful at the present day, effecting wonderful economies, 
 needing only simple and compact plant, and bringing 
 about the required changes in the cleanest and least 
 wasteful manner. 
 
 The Ammonia-Soda or Solvay Process. In this 
 process sodium bicarbonate is produced by the action 
 of carbon dioxide on an ammoniacal solution of 
 common salt. The bicarbonate crystallises out, 
 leaving ammonium chloride in solution, the ammonia 
 being recovered by heating the solution with lime, 
 and used over again. The lime employed is burnt at 
 the works, the lime-kiln gas being the source of some 
 of the carbon dioxide, while the gas expelled from 
 the bicarbonate by calcination to make normal 
 carbonate provides the remainder. The salt solution 
 
32 WHAT INDUSTRY OWES 
 
 used brine pumped up from brine pits is subjected 
 to preliminary purification. Magnesium salts are 
 precipitated by the addition of lime, the lime salts 
 being afterwards removed by adding the necessary 
 quantity of sodium carbonate or ammonia liquor 
 containing ammonium carbonate. After settling the 
 solution is drawn off and is then ready for use. 
 
 This process, which was patented by Dyer and 
 Hemming in 1838, though simple from the chemists' 
 point of view, presented considerable mechanical 
 difficulties. The first attempt to utilise the reaction 
 on the large scale was made by Schloessing and 
 Holland in 1855, at a works near Paris. At the end 
 of two years, however, the difficulties remained 
 unsolved and the project was abandoned. In 1863, 
 Solvay, who had taken out a patent two years earlier, 
 erected an experimental factory near Brussels ; as the 
 result of perseverance, he secured the success of the 
 process, and in 1872 established a far larger works 
 near Nancy. Two years later the process was intro- 
 duced into this country, under the Solvay patents, by 
 Mond, continued by Brunner, Mond and Co., Limited, 
 at Northwich, where for the first time natural brine 
 was employed and other improvements were adopted. 
 In 1895 the production by the Solvay process exceeded 
 that by the Leblanc process, over which it has several 
 incontestable advantages. The use of brine from the 
 pits effected a great economy that could not be 
 shared by the older process. The Solvay process is 
 cleaner and the product purer. There is, of course, 
 no sulphur to be recovered, but the chlorine from the 
 salt is frequently wasted as calcium chloride. As an 
 improvement in the process, magnesia is now used in 
 some cases to liberate the ammonia from the mother 
 liquor, the resulting magnesium chloride being 
 subsequently decomposed by heat into magnesia (to 
 be used over again) and hydrochloric acid. 
 
 Before leaving the subject of alkali we must note 
 that electrolytic methods of manufacture form an 
 increasingly important branch of the industry. 
 Solutions of common salt are electrolysed in a special 
 vessel, of which the Castner rocking cell is a type, 
 
TO CHEMICAL SCIENCE 33 
 
 and caustic soda and chlorine, both marketable 
 products, are obtained in separate compartments. 
 When the process is modified so that the chlorine 
 is allowed to come into contact with the soda solution, 
 chlorate or hypochlorite may be produced by 
 employing hot or cold solutions respectively. The 
 value of chlorates has already been indicated ; 
 sodium hypochlorite is used as a bleaching agent and 
 as an ingredient in one step of the manufacture 
 of indigo. 
 
34 WHAT INDUSTRY OWES 
 
 CHAPTER III. 
 COAL AND COAL GAS. 
 
 WE live in an age of coal and iron. The great war 
 is waged very much with coal or rather, what we 
 get from it and iron ; on the manipulation of these 
 substances by engineers and chemists the produc- 
 tion of munitions of war largely depends. Some of 
 the coal we use to smelt the iron ore and to fashion 
 the metal into convenient form for our use. When 
 we have won the iron we can use it, scrap it, and use 
 it again many times, but the coal once used is 
 destroyed for all time. The world's annual production 
 of this valuable mineral probably exceeds 1 ,335,000,000 
 short tons, and it is utilised (1) as a domestic fuel, 
 with which we are all familiar ; (2) as a source of 
 mechanical and electrical power through the agency 
 of steam ; . (3) as a reducing agent in certain chemical 
 and metallurgical operations ; (4) for the production 
 of coke in ovens ; (5) as a source of gas for illumi- 
 nating and heating purposes and of many other 
 valuable products. 
 
 The influence of scientific thought on the second of 
 these uses is well known, though perhaps its extent 
 is not always clearly recognised. For more than 
 half-a-century, steam engines were designed to meet 
 the requirements of coal as a fuel. It was the bed- 
 rock of the art of engineering. The abundance of 
 coal gave impetus to invention and the modern steam 
 engine is the result of the co-operation of physicists, 
 chemists and mathematicians, with the practical engi- 
 neer. As a reducing agent in applied chemistry and 
 metallurgy coal itself is less used than coke. The 
 ironmaster is a great consumer of coke-oven coke as 
 a reducing agent, and it has found an important use 
 in the manufacture of water gas and producer gas. 
 
TO CHEMICAL SCIENCE 35 
 
 The first, a mixture rich in hydrogen and carbon 
 monoxide, is obtained by passing steam through red 
 hot coke ; the second, a mixture of carbon monoxide 
 and atmospheric nitrogen is formed by the similar 
 treatment of carbon dioxide produced by the com- 
 bustion of coke. Although water gas has a much 
 greater calorific power than producer gas, it is not 
 economical to make it alone, because the reaction 
 between the coke and the steam is endothermic and 
 the coke chamber must be heated externally to main- 
 tain the requisite temperature. Dowson gas and 
 Mond gas are mixtures intermediate between water 
 gas and producer gas, made by combining the two 
 processes and passing a mixture of steam and air over 
 the red hot coke. When the coke cools during the 
 operation the temperature is raised again by cutting 
 off the steam and allowing air alone to pass through. 
 The use of these gases for heating purposes is very 
 economical and finds extensive application. 
 
 As one of the most striking examples of the influence 
 of science in industry, coal gas manufacture demands 
 consideration in somewhat fuller detail, treating of 
 the distillation of a highly complex body from which 
 the chemist has obtained a vast variety of useful 
 substances. The history is interesting also as an 
 illustration of a development of philosophical experi- 
 ment. In the seventeenth century the pursuit of 
 science was the hobby of many men of learning and 
 particularly of the clergy. The Rev. Dr. Clayton, 
 rector of Crofton, distilled gas from coal and collected 
 it in a bladder ; the fact being communicated, in 
 1688, to the Royal Society by Boyle. In 1750, Dr. 
 Watson, Bishop of Llandaff, not only distilled gas 
 but conveyed it in pipes from one place to another. 
 The credit, however, is given to an engineer, William 
 Murdock, for the first suggestion that coal gas should 
 be generally employed for lighting purposes. In 
 1792 he conveyed it from iron retorts through tinned 
 iron and copper pipes, tapped at intervals, a distance 
 of 70ft., lighting his house and offices. His early 
 experiments were carried out at Redruth, and six 
 years later he lighted the Soho foundry of Boulton and 
 
36 WHAT INDUSTRY OWES 
 
 Watt, at Birmingham. In 1799, Le Bon commenced 
 similar experiments in France. In 1807, after one 
 side of Pall Mall had been lighted by Winsor, a Bill 
 was promoted in Parliament to authorise a company 
 for the supply of gas in London ; in 1810 an Act was 
 passed for this purpose, and two years later a charter of 
 incorporation was granted to the Gas Light and Coke 
 Company, still by far the largest gas undertaking in 
 the world. Westminster Bridge and the Houses of 
 Parliament were lighted in 1813, and from that time 
 the practice of gas lighting spread rapidly in all 
 civilised countries. 
 
 The gas industry is essentially chemical, though it 
 was formerly entirely controlled by engineers. There 
 was a time when gas engineers were disinclined to 
 show much appreciation of the chemical aspects of 
 the industry. In some works the chemists, if any 
 were employed, were exclusively relegated to the 
 laboratory for routine testing without any opportunity 
 of acquiring experience in large scale operations. The 
 remuneration and prospects of such chemists were so 
 poor that few worthy of the name could be induced 
 to remain long in such employment. In many 
 important works, however, chemists acquired the 
 essential knowledge of the engineering side of the 
 industry, led the way in the introduction of improved 
 methods and effected developments of a far-reaching 
 character, especially in the profitable utilisation of 
 material hitherto regarded as waste and the manu- 
 facture of new products. 
 
 Enormous quantities of coal are subjected to 
 destructive distillation to obtain its numerous and 
 valuable decomposition products, of which gas, tar, 
 ammonia and its salts, coke, and gas carbon are made 
 on a huge scale and all consumed. The gas provides 
 light and heat, whilst the tar, useful in many ways in 
 the crude state, gives, when distilled, benzene, toluene, 
 solvent naphtha, carbolic acids, naphathalene, anthra- 
 cene, and many other substances, which in their turn 
 yield, in the hands of the technologist, a host of further 
 useful bodies, including explosives, dyes, disinfectants, 
 and drugs. Pitch, the residue of tar distillation, is 
 
TO CHEMICAL SCIENCE 37 
 
 used largely in the manufacture of patent fuel and 
 provides excellent material in road making. Ammo- 
 nia is employed in medicine, in the laboratory, and in 
 cleaning cloth, and there are many uses for its salts, 
 especially the sulphate, a valuable fertiliser. Gas 
 carbon, a hard, compact substance, is used by electrical 
 engineers in the operation of arc lamps and fur- 
 naces, and as a fuel in making producer gas. 
 
 The purified coal-gas of commerce roughly consists 
 of hydrogen about 50 per cent, by volume, and 
 marsh gas or carburetted hydrogen about 35 per cent., 
 carbon monoxide 5 per cent., heavy hydrocarbons 
 5 per cent., and nitrogen 5 per cent. As it issues 
 from the hydraulic mains, which receive the vapour 
 from the ascension pipes from the retorts, it is not 
 at once ready for delivery to the consumer. Besides 
 its essential constituents, it contains substances 
 such as condensable hydrocarbons, ammonia, carbon 
 dioxide, carbon bisulphide, sulphuretted hydrogen, 
 cyanogen, and cyanides, some of which are of sufficient 
 value to pay for their extraction, all being undesirable 
 impurities on account of their reducing the heating 
 power of the gas or of the objectionable character 
 of the products of their combustion. These bodies 
 are therefore removed by condensation by cooling, 
 " scrubbing " with water, and by passing the gas 
 over suitable materials. The operation of scrubbing 
 with water or with aqueous liquors from the hydraulic 
 mains removes the ammonia and part of the carbon 
 dioxide. The gas then passes into a chamber 
 containing moist slaked lime, where cyanogen com- 
 pounds and the remainder of the carbon dioxide 
 are removed, the former in a state from which they 
 cannot be recovered. Their recovery from the gas, 
 however, can be effected, when desired, by a pre- 
 liminary treatment with oxide of iron before the 
 gas passes through the lime chambers. 
 
 After the lime treatment the gas is led over moist 
 oxide of iron, or Weldon mud, for absorption of 
 the sulphuretted hydrogen, the material when 
 spent being revivified by action of the air. The 
 gas next passes over sulphided lime the substance 
 
 D 2 
 
38 WHAT INDUSTRY OWES 
 
 formed by the action of sulphuretted hydrogen on 
 slaked lime to eliminate carbon bisulphide, and, 
 finally, undergoes an extra check treatment with 
 oxide of iron, or Weldon mud, to remove any traces 
 of sulphuretted hydrogen taken up from the sulphided 
 lime. Subject to passing the prescribed tests for 
 illuminating and heating power, the gas now passes 
 to the holder in ordinary parlance the gasometer 
 and is ready for the public supply. 
 
 It is obvious that science is responsible for such 
 a process of purification. There is scope for chemistry, 
 physics, and mechanics in every step. 
 
 We have stated that the pipes from the retorts 
 convey the vapour to the hydraulic main, where it 
 is partially condensed, and the liquid thus condensing 
 forms two layers, coal tar and aqueous liquor. The 
 latter is uppermost, and contains ammonia and other 
 soluble bodies. The tar was for long the bugbear 
 of gas manufacture, its disposal being a difficult 
 problem, but now it is of such value that the industry 
 of tar distillation has grown to be of great importance. 
 It is distilled in large iron stills, the vapours evolved 
 from which are condensed, the distillate being 
 separated into fractions as follows : First runnings 
 up to 105 deg. Cent. ; light oil from 105 to 210 deg. 
 Cent. ; carbolic oil from 210 to 240 deg. Cent. ; creosote 
 oil from 240 to 270 deg. Cent. ; anthracene oil from 
 270 up to the pitching point, this last temperature 
 being determined by the quality of pitch desired. 
 The first runnings form two layers in the receiver, 
 consisting of ammoniacal liquor and crude naphtha. 
 These are separated, the former being added to the 
 bulk of ammoniacal liquor, the latter being reserved 
 for subsequent treatment. The second or light oil 
 fraction, consisting mainly of hydrocarbons of the 
 benzene series, is first re-distilled, yielding first 
 runnings, which are added to the crude naphtha 
 from the original tar first runnings, and last runnings 
 which are worked up with the carbolic oil. 
 
 The crude naphtha is washed with caustic soda 
 solution to remove phenols in an easily recoverable 
 fonn ; then with strong sulphuric acid, which dis- 
 
TO CHEMICAL SCIENCE 39 
 
 solves bases and unsaturated bodies, and carbonises 
 other impurities, forming substances of a heavy, 
 tarry nature, and finally another soda washing is 
 given to remove the residual sulphuric acid. The 
 spent sulphuric acid Is used in the ammonia plant 
 for the production of sulphate of ammonia. The 
 naphtha so far purified is next redistilled from an 
 iron still. Two fractions are collected crude benzol 
 up to 140 deg. Cent., and solvent naphtha from 140 
 to 170 deg. Cent., the residue in the still being reserved 
 for addition to the carbolic oil. From the crude 
 benzol are obtained by further acid and alkali washing 
 and careful fractionation, forerunnings of benzol, 
 containing benzene, toluene, carbon bisulphide and 
 thiophenes, commercial and pure benzol and toluol, 
 and solvent naphtha. Benzols and toluols are used 
 by the dye manufacturers, and at the present day in 
 enormous quantities in the manufacture of explosives, 
 benzene being the starting point in one process 
 for making picric acid, toluene being the material 
 from which T.N.T. is made. Solvent naphtha is 
 used as a solvent for india-rubber, the higher boiling 
 portions containing naphthalene, forming a fuel for 
 naphtha lamps. 
 
 The carbolic oil is treated by cooling to separate 
 naphthalene, and subsequently washing with a 
 solution of caustic soda, which dissolves the carbolic 
 and cresylic acids. These acids are recovered by 
 neutralising the solution with sulphuric acid, when 
 crude carbolic acid and sodium sulphate are formed, 
 the former being subsequently worked up for pure 
 carbolic acid and cresylic acid, both used in the 
 manufacture of dyes, disinfectants, and explosives. 
 A modification of the above method is that known as 
 the West-Knight and Gall process, whereby the 
 oil is treated with a mixture of sodium sulphate 
 solution and lime for the production of sodium 
 " carbolate " and sulphate of lime. The solution 
 is worked up as before, the sodium sulphate being 
 utilised again for mixing with more lime. The 
 insoluble oil is either mixed with the light oil or is 
 worked up for naphthalene. 
 
40 WHAT INDUSTRY OWES 
 
 Creosote oil is of value as a source of naphthalene, 
 and for preserving wood from the action of the 
 weather and destructive insects. Naphthalene, once 
 a waste product, is now used largely in the manufac- 
 ture of dyes, being the parent substance of artificial 
 indigo, as an insecticide, and in other minor roles. 
 Anthracene oil is the source of anthracene, a condensed 
 hydrocarbon of the benzene series, from which the 
 alizarin dyes are made. 
 
TO CHEMICAL SCIENCE 41 
 
 CHAPTER IV. 
 DYES, EXPLOSIVES AND CELLULOSE. 
 
 THE invention of dyeing has been attributed to the 
 Phoenicians, probably because it is chronicled that 
 Solomon sent to Hiram of Tyre for " a man cunning 
 to work " inter alia " in purple and crimson and blue." 
 The Tyrian purple was derived from the throats of a 
 species of murex, a molluscous animal, a single drop 
 from each. Other dyes from animal substances 
 include sepia derived from the black secretion of the 
 cuttlefish, and cochineal which consists of dried female 
 cochineal insects, discovered by the Spaniards in 
 1518. 
 
 The importance of the dye industry is not so much 
 in the value of the dyes as in the vast interests of the 
 textile industry with which it is so intimately 
 associated. At a high estimate this country does not 
 use annually dyes to the value of 2,000,000, or, say, 
 less than Is. per head, presuming the use to be 
 confined to the British Isles ; but the various industries 
 affected exceed in annual value a sum of 200,000,000, 
 and the labour involved in dyeing and printing 
 processes is not far short of 2,000,000. Clearly then 
 we cannot afford to be dependent on other countries 
 for supplies of materials of this kind so long as we have 
 the power to produce them ourselves. It is well 
 known that the Government has now given active sup- 
 port to the industry ; and we may rejoice that British 
 Dyes, Limited, and other British dye concerns are 
 making good progress towards its firmer establishment. 
 Even before the outbreak of war, progress had been 
 made in certain directions towards successful com- 
 petition with the Germans, and since the war, by the 
 aid of science, discoveries have been made which, in 
 the view of the enemy producers, were calculated to 
 
42 WHAT INDUSTRY OWES 
 
 defy our chemists for at least ten years. Compared 
 with the period occupied by the Germans in dis- 
 covering artificial indigo about thirty-five years and 
 an expenditure of over 1,000,000 the taunt may be 
 taken as a compliment ; but in two years from the 
 discovery of artificial indigo 426,100 out of 755,900 
 acres of plantations went out of cultivation. It was 
 first sold in 1897 and in the course of a few years drove 
 the natural dyestuff out of the markets of the world, 
 being only about one-third of the price, and the busi- 
 ness passed from India to Germany. 
 
 The history of the subject covering the consideration 
 of all the dyes known would fill volumes exceeding in 
 bulk the " Encyclopaedia Britannica." The number of 
 dyes revealed by science and the substances which 
 science can foretell with certainty would form dyes, 
 and the myriad derivatives of known colouring 
 matters, would run into many thousands, though 
 800 to 1000 should be more than sufficient for all 
 practical purposes. 
 
 The artificial dyes have several advantages over 
 natural products. The range of shade for any colour 
 can be extended and graded by the employment of 
 suitable materials in a manner that cannot be attained 
 by using the natural dyes ; the purity of artificial 
 dyes is much greater, and the total cost of production is 
 considerably less. On account of this superiority of 
 synthetic dyes, the cultivation of indigo and madder, 
 and the trade in cochineal have been almost completely 
 overshadowed. Both indigo and madder have been 
 investigated by scientific men, and the composition 
 and nature of the dyestuffs determined. Further 
 researches have led to the discovery of methods of 
 synthesis of these substances, not only interesting 
 from an academic point of view, but capable of holding 
 their own and beating their natural prototypes in 
 commercial competition. The use of cochineal has 
 been largely replaced by the discovery and utilisation 
 of azo-red dyes which imitate the colour very closely, 
 such, for example, as Bieberich scarlet. The most 
 important material used in the economical manu- 
 facture of indigo is naphthalene obtained from the 
 
TO CHEMICAL SCIENCE 43 
 
 creosote oil fraction of the tar distiller by cooling, 
 washing the crystals produced with alkali and with 
 acid, and distilling or subliming the product. Other 
 ingredients are chloracetic acid and sodium hypo- 
 chlorite, the preparation of which provides one of the 
 numerous outlets for the elementary chlorine of the 
 alkali manufacturer. A short sketch of the method 
 of Heumann will not be out of place. 
 
 Naphthalene is converted into phthalic anhydride 
 by heating with sulphuric acid and mercuric sulphate. 
 The phthalic anhydride in turn is transformed into 
 phthalimide by heating under pressure with ammonia. 
 By the action of sodium hypochlorite on phthalimide, 
 anthranilic acid is produced and this substance, when 
 treated with chloracetic acid, yields phenyl glycine- 
 carboxylic acid, which by fusing with alkali, dissolving 
 the melt in water and passing a stream of air through 
 the solution, yields indigo blue. This complex series of 
 operations has met with complete commercial success. 
 
 Alizarin, the dyestuff contained in madder, is made 
 from anthracene, another coal tar product, by the 
 action of sodium bichromate and sulphuric acid to 
 form anthraquinone ; this is transformed by the action 
 of sulphuric acid into anthraquinone sulphonic acid, 
 the sodium salt of which when fused with soda and 
 a little potassium chlorate yields a compound of 
 alizarin containing sodium, from which alizarin itself 
 is made by the action of acid. 
 
 Bieberich scarlet, one of the naphthol azo dyes, 
 a very important group, is, like indigo, prepared from 
 naphthalene as starting material. 
 
 These three examples serve to show how the 
 laboratory and the factory have replaced the cultiva- 
 tion field. There are also thousands of new dyes 
 prepared from benzene, toluene, and carbolic acid, as 
 well as many others from naphthalene. The name 
 " coal tar dyes," however, is rather misleading to the 
 uninitiated, for it seems to imply that the dyes exist as 
 such in the tar and only need extraction. What is 
 meant, is that the raw materials are found in the tar 
 and need to be transformed before anything of the 
 nature of a dye can be produced. 
 
44 WHAT INDUSTRY OWES 
 
 The recovery and utilisation of these tar products 
 in the manner indicated is a great achievement. The 
 first known coal tar colour mauveine was made from 
 aniline by Perkin in 1856, aniline having been 
 discovered by Unverdorben, thirty years earlier, by 
 distilling indigo. 
 
 Dyeing. The processes of dyeing and calico 
 printing are definitely chemical and depend entirely 
 on scientific control. Dyes are transparent and the 
 effects they produce vary according to the light 
 reflected by the fibres of materials before they are 
 dyed. Obviously, therefore, black cannot be dyed, 
 and such colours as red, blue, and yellow can only 
 be dyed in the same hues, unless the material, as is 
 possible in the case of velvets and velveteens, be 
 previously bleached. White reflects all rays and 
 is essential as the basis for bright dyes. There must 
 be chemical combination between the colouring 
 matter and the cloth, and the dye must be dissolved 
 in a solution having a weaker affinity for the colour 
 than the cloth, while for economical working there 
 must be accurate adjustment between these relations. 
 Wool has a stronger affinity for dyes than silk, cotton, 
 or linen. The solutions used must be varied as 
 occasion requires. The choice of dyes for a given 
 material involves the consideration of fastness to 
 washing, and the action of light. Certain dyes will 
 fix themselves directly to certain fibres but not to 
 others without the use of mordants. The mordants 
 commonly employed, such as tannin, and the oxides of 
 iron and aluminium, were discovered empirically, 
 but science has explained their action, while research 
 has contributed to the discovery of many new kinds 
 of colouring matter. In the art of dyeing the neglect 
 of science is mainly responsible for the loss incurred 
 by spoiled and impoverished material. 
 
 EXPLOSIVES. 
 
 From a brief review of one of the most interesting 
 arts of peace we will pass to one of the principal 
 industries of war. The methods of production of 
 explosives are so closely allied to those of the coal 
 
TO CHEMICAL SCIENCE 45 
 
 tar dyes that without much modification of plant 
 the dye maker can turn his attention to the war 
 industry. We will not go so far as to suggest that 
 the development of the dye industry of the Germans 
 was part of their plan of preparations for war, 
 but they have undoubtedly been able to take 
 advantage of the existence of their great factories 
 for fine chemicals and dyes in this connection. From 
 the discovery of pulvis fulminans by Roger Bacon 
 in the thirteenth century, the invention of gunpowder 
 and guns by Swartz, the monk of Cologne, in the 
 fourteenth, and the first use of cannon in ships in 
 the sixteenth century, there was little development 
 in the science or industry of explosives until the 
 nineteenth century; then, of course, the need for 
 explosives in mining and engineering was far in excess 
 of that for war. Our present business is not to 
 moralise, but to indicate with caution what science 
 has done for an industry, the foundation of which 
 lies in the realisation, by scientific men, of the causes 
 of explosion. An explosive compound or mixture 
 is one that can be converted exothermically and with 
 great rapidity into gaseous products which at the 
 high temperature attained would occupy at ordinary 
 pressure a much greater space than that occupied 
 by the original compound or mixture. The enormous 
 pressure generated by sudden expansion constitutes 
 the explosive force, and the principle involved has 
 led to the utilisation of the explosive nature of a 
 number of substances possessing this property which 
 might otherwise have been overlooked. For instance, 
 it is not at all easy to bring about the explosion of 
 trinitrotoluene, or T.N.T. It is a relatively stable 
 substance ; but a study of its nature and comparison 
 with picric acid, a similarly constituted body of 
 known explosive properties, would lead one to suppose 
 that it could be detonated by percussion. 
 
 In 1832, Braconnot demonstrated the formation 
 of an explosive substance by the action of nitric 
 acid on wood fibre, and in 1845 Schonbein obtained 
 gun-cotton by treating cotton with a mixture of 
 sulphuric and nitric acids. Its manufacture, however, 
 
46 WHAT INDUSTRY OWES 
 
 though started in several foreign countries, was not 
 successful, the production being unstable and 
 dangerous, owing to lack of care in the details of 
 the operations involved. Sir Frederick Abel showed 
 not only that must the starting material, cotton 
 waste, be carefully selected, but that thorough water 
 washing after nitration was an important factor. 
 The instability of the Schonbein material was due 
 to the presence of free acids. The introduction of 
 centrifugal driers and of paper pulping machines for 
 breaking up the cotton fibre facilitated the wash- 
 ing process, and reduced the risk of manufac- 
 ture. 
 
 Gun-cotton is used for a variety of military 
 purposes, such as filling subterranean and submarine 
 mines and torpedoes, and it possesses the great 
 advantage that it can be exploded when wet, although 
 the wet substance is safe for handling, transportation, 
 and storage. When dry, it is exploded by a primer 
 of fulminate of mercury ; when wet, a primer of 
 dry gun-cotton is used. The explosive power of 
 gun-cotton led to attempts being made to use it as 
 a propellant, but gun-cotton, as such, is not suitable 
 for the purpose because its explosion is very rapid, 
 violent, and uncertain. Attempts to " tame " it by 
 gelatinisation with certain organic liquids met with 
 success in the smokeless powders of Walter F. Reid 
 and Vieille. The most remarkable result in this 
 direction, however, was achieved by Alfred Nobel, 
 who produced a homogeneous mixture of gun-cotton 
 and nitroglycerine by the evaporation of a solution 
 of those substances in acetone. By the modern 
 development of this method, gun-cotton, nitro- 
 glycerine, and a small quantity of mineral jelly are 
 mixed well with acetone, and the resulting paste 
 is squeezed through jets to form continuous cords, 
 which, when dry, have the appearance of catgut. 
 This is cordite, the propellant explosive used in 
 firearms of many sorts and sizes. 
 
 Nitroglycerine, mentioned above, was discovered 
 by Sobrero, in 1847, but its explosive properties 
 were not utilised until its value was recognised by 
 
TO CHEMICAL SCIENCE 47 
 
 Nobel. It is a fairly heavy oily liquid, detonating 
 violently by percussion, when struck a sharp blow, 
 or suddenly heated. On account of these propensities 
 the substance, as such, is seldom, if ever, employed 
 at the present time, but is converted into a safer 
 form by incorporation with some inert material, as, 
 for example, magnesia alba, or kieselghur, the 
 product in the latter case being dynamite. In this 
 form, although a certain amount of danger still 
 attends its use, it is much safer than in the free state. 
 Sometimes nitroglycerine is incorporated with an 
 explosive diluent, as with collodion cotton, to 
 produce blasting gelatine, a body with explosive 
 power exceeding that of nitroglycerine ; while a 
 mixture of thinly gelatinised nitroglycerine with nitre, 
 woodmeal, and a trace of soda, gives us gelatine 
 dynamite, another useful blasting agent. Explosives 
 of this class, used largely in mining, quarrying, and 
 civil engineering operations, have been specially 
 developed by Nobel's Explosives Company. 
 
 When we come to consider the class of substances 
 used for the bursting charge of shells, it is difficult 
 to give any individual the credit for their first applica- 
 tion, or, shall we say, " give the devil his due." 
 Picric acid, the oldest of these, was discovered in 
 1799 by Welter, and its nature as a derivative of 
 phenol was elucidated by Laurent in 1 842. Preparations 
 of picric acid are used by various countries, as a military 
 high explosive under such names as lyddite, shimose, 
 and melinite. Its great disadvantage is that it forma 
 very sensitive and highly explosive salts when left 
 in contact with metals for any length of time. This 
 drawback is not shared by T.N.T., which has come so 
 much into use during the war. The substitution 
 of T.N.T. involves a loss of explosive power, but this 
 is more than counterbalanced by the advantages 
 gained. It is used both alone and in conjunction 
 with other substances such as aluminium powder and 
 ammonium nitrate. Such a mixture is ammonal, 
 a safe but very powerful explosive employed by the 
 Austrians. Another very violent explosive is tetra- 
 nitroaniline, discovered by Fleurscheim. It is not 
 
48 WHAT INDUSTRY OWES 
 
 very largely used, as the materials required for its 
 manufacture are comparatively expensive. 
 
 The whole industry is based on science, and should 
 be controlled by trained men of science in every 
 department. It has demanded its toll of human life, 
 in spite of extraordinary precautions ; but without 
 science that toll would have been far greater, and 
 certain it is that without the search for knowledge, 
 the desire to experiment, and the power to apply 
 the knowledge gained, such an industry could not 
 exist. 
 
 CELLULOSE. 
 
 Cellulose. Cellulose belongs to the class of sub- 
 stances known chemically as carbohydrates. All 
 carbohydrates consist of carbon, hydrogen, and 
 oxygen, the second and last occurring in the same 
 proportions as in water. 
 
 Cellulose is not affected by ordinary solvents, but 
 is attacked by strong sulphuric acid, yielding a 
 starch-like body called amyloid, and is dissolved by 
 ammoniacal solutions of copper salts, from which 
 it can be precipitated in an amorphous form by the 
 addition of acids. This property constitutes the basis 
 of one method of making artificial silk. It may be 
 mentioned, incidentally, that when heated to 200- 
 220 deg. Cent, with caustic potash, cellulose is broken 
 down into oxalic acid, and large quantities of that 
 acid are made in this way. Sawdust is fused with 
 potash in iron pans ; the melt when cold is extracted 
 with water, and the oxalic acid is precipitated as the 
 insoluble calcium salt from which it is subsequently 
 liberated by the action of sulphuric acid. This 
 process, which was discovered by Gay-Lussac in 1829, 
 and was first employed on the manufacturing scale 
 by Dale in 1856, is far cheaper than the older method 
 of oxidising sugar or starch with nitric acid. 
 
 The cellulose industry is held to include the manu- 
 facture of cotton, linen, paper and pasteboard, and 
 hemp and jute articles. We do not claim much in 
 the way of debts to science in connection with the 
 
TO CHEMICAL SCIENCE 49 
 
 manufacture of cotton and linen, but will choose 
 paper and pasteboard for our purpose, and then refer 
 briefly to artificial silk and celluloid. 
 
 Paper may be regarded as one of the civili- 
 sing agents in the existence of man. It is diffi- 
 cult to imagine what progress the world would 
 have made without it. The early history of paper 
 is obscured by conflicting records. It is believed 
 to have been used in China long before the Greeks 
 and Romans ceased to use papyrus, but according 
 to M. Terentius Varro, a voluminous writer contem- 
 porary with Cicero, the invention was devised at 
 Alexandria on the conquest of Egypt by Alexander 
 the Great (B.C. 331). It was in use in Arabia over 
 1000 years ago, and the Crusaders are said to have 
 brought the industry to Europe. The earliest MS. 
 on cotton paper in the Bodleian Collection in the 
 British Museum is dated 1049, while one on the same 
 material in the Library of Paris is dated 1050. Paper 
 made of linen rags was in use here in 1170. The 
 Moors are credited with having introduced the 
 industry into Spain, where 12th century specimens 
 still exist. The first paper mill in this country was 
 established by Tate, in Hertfordshire, in the reign 
 of Henry VII., who visited it, and the first important 
 one was started at Dartford, in Kent, in 1588, or 
 thereabouts, when Queen Elizabeth granted a 
 monopoly, for gathering rags and making paper, 
 to Spielmann, the Court Jeweller. 
 
 Until the end of the 18th century paper was made 
 by tearing and beating rags to pulp in a machine, 
 dipping a wire sieve into the pulp, transferring the 
 mass to a felt and pressing it in moulds of various 
 sizes. About 1800 a Frenchman devised a method 
 of making it in a continuous web, which he introduced 
 into England, where it was steadily improved until 
 about 1860, by which time, for all ordinary purposes, 
 it had superseded the old hand-made method, 
 although the latter is still employed for bank notes, 
 bonds, ledgers, and important documents. 
 
 With the introduction of machine-made papers 
 
50 WHAT INDUSTRY OWES 
 
 the output has been vastly increased, the cost reduced, 
 and the variety extended to such a degree that there 
 are now probably more than 20,000 kinds. In 1820 
 the machines produced paper at the rate of about 
 40ft. per minute ; the most modern can now exceed 
 500ft. per minute. Before 1860, paper consisted 
 almost entirely of rags, but about that time an 
 Englishman introduced the use of esparto, Macrochloa 
 (or Stipa) tenacissima, a grass also employed for making 
 mats, nets, baskets, &c., of which the consumption in 
 paper-making is normally about 200,000 tons a year, 
 at 4 to 4 10s. per ton, almost all of it coming to this 
 country for the production of fine printing papers. 
 Over 400 different materials have been tried in the 
 industry, but rags and esparto are the chief for good 
 papers. Since the year 1880, chemical wood pulp 
 has been used as the chief material for middling 
 kinds, and more recently mechanical wood made by 
 crushing wood between rollers or by pressing it 
 against a grindstone mixed with varying quantities 
 of chemical wood pulp, has been employed for the 
 cheapest newspapers and common printings. 
 
 Science has played an important part in the 
 development of the paper industry. The introduction 
 of cheap bleaching agents such as chloride of lime 
 to which, as a by-product of the Leblanc process 
 we have already referred, has effected considerable 
 improvements and economies, while the utilisation of 
 esparto and wood has been made practicable only 
 by scientific research, the processes evolved from which 
 we will now outline. 
 
 Wood fibre is a lignocellulose, a compound of 
 cellulose and a complex substance called lignone, 
 which acts apparently as a binding material. The 
 forest wood is deprived of its bark and cut across the 
 grain into small chips, which are cleaned and then 
 boiled at high temperature, under pressure, in a 
 solution of caustic soda. From coniferous wood the 
 yield of cellulose is about one-third of the weight 
 of the prepared wood treated, the other two-thirds 
 being taken up by the alkaline solution. The caustic 
 soda required, amounting to about 20 per cent, of 
 
TO CHEMICAL SCIENCE 51 
 
 the weight of the wood, is recovered by evaporating 
 the spent liquor, incinerating the residue and treating 
 a solution of the ash with lime. The organic matter 
 in the residue, on burning, provides a good deal of 
 the heat necessary for evaporating the solution. 
 The process, however, has one disadvantage in the 
 fact that a proportion of the cellulose is destroyed 
 by the action of the strong alkali. In order to obtain 
 better yields two modifications have been introduced 
 comparatively recently. One consists in the sub- 
 stitution of sodium sulphide for the caustic soda, 
 the sulphide being prepared on the spot by the reduc- 
 tion of sulphate of soda with the residue obtained 
 by evaporating the spent alkali. The cycle of 
 operations is then completed by making up the 
 working loss of sodium sulphide by the addition of 
 sulphate of soda to the residue before incineration. 
 The other modification consists in the application 
 of an acid hydrolysing agent instead of the alkali. 
 The acid substance employed is a solution of calcium 
 or magnesium bisulphite containing approximately 
 4 per cent, of sulphur dioxide. This solution is 
 prepared by passing pyrites gases up a tower filled 
 with calcite or dolomite down which water is trickling. 
 The cost of the process is slightly higher, but not out- 
 of proportion to the increased yield of cellulose. 
 
 The cellulose obtained by either of the methods 
 is mashed to a pulp, washed free from adhering liquor, 
 and bleached with chloride of lime and sulphuric 
 acid, before being utilised in the manufacture of 
 paper. Those who are interested in this subject may 
 be invited to study the series of articles on " Paper 
 Making," which appeared in Vol. CXX. of THE 
 ENGINEER. 
 
 " Artificial Silk" The production from cellulose 
 of materials resembling silk is the result of many 
 years of scientific research and costly experiment. 
 In 1889 the Comte de Chardonnet produced the 
 first artificial silk by nitrating cellulose and dissolving 
 the resulting product in a mixture of alcohol and 
 ether, thereby obtaining a viscous liquid which he 
 forced through holes of very small diameter into water. 
 
52 WHAT INDUSTRY OWES 
 
 The threads thus produced were then subjected to 
 the reducing action of ammonium sulphide and con- 
 verted into an amorphous cellulose having the 
 appearance of silk. 
 
 The method now extensively used is that devised 
 by Cross and Bevan, who have contributed largely 
 to the existing knowledge of the chemistry and 
 technology of cellulose. The starting material, 
 wood pulp, is treated successively with caustic soda 
 solution and carbon bisulphide, the viscous mass 
 thus obtained being forced through small apertures, 
 from which are produced filaments which are spun 
 into a fine material also closely resembling silk. 
 
 Celluloid a very useful substitute for horn, 
 tortoiseshell, ivory, &c. was first made in 1869 
 by treating nitrocellulose with camphor and alcohol. 
 Its inflammability, however, has proved to be a 
 very serious drawback, attempts to overcome which 
 have met with some success. By the substitution 
 of acetate of cellulose for cellulose itself in the process, 
 a non-inflammable product sicoid or cellon is 
 formed which for some purposes is more useful 
 than celluloid. 
 
TO CHEMICAL SCIENCE 53 
 
 CHAPTER V. 
 OILS, FATS AND WAXES. 
 
 OILS may be divided into : (a) animal, including 
 whale and fish oils, stearin, which is mainly obtained 
 from beef and mutton suet, and neats-foot oil from 
 the feet of cattle ; (ft) vegetable, such as olive, linseed, 
 cotton seed, maize, palm, rape, castor, and turpentine, 
 and essential oils ; and (c) mineral oils, so-called, such 
 as petroleum, ozokerite, and shale. It is difficult to 
 make a sharp division, however, for the reason that 
 some are obtained from more than one of these sources ; 
 for instance, stearin exists in the vegetable kingdom, 
 and petroleum is certainly derived from the products 
 of long submerged fish life. The tar oils we have 
 already noticed in dealing with coal and coal gas. 
 Among the most useful substances at our disposal 
 oils are employed as fuel, illuminants and lubricants, 
 and provide us with material for food and medicine, 
 as well as for the manufacture of paints and varnishes, 
 polishes and perfumes. 
 
 Oil has been defined as a neutral fatty substance, 
 liquid at ordinary temperatures ; but although we are 
 not satisfied with the definition, we will not attempt 
 to improve upon it, preferring rather to proceed with 
 our task of indicating th influence of science in the 
 vast field of industry involved. That influence has 
 been more marked in the direction of improvement 
 and adaptation rather than of new and striking dis- 
 covery. In some cases, however, scientific principles 
 have been applied to the fundamental processes of 
 oil production, with the result that substances at one 
 time ignored as valueless have become the source of 
 products now regarded as indispensable, while the 
 science of geology has rendered inestimable service in 
 locating and surveying sources of mineral oil ; indeed, 
 
 E 2 
 
I 
 
 54 WHAT INDUSTRY OWES 
 
 a knowledge of economic geology is essential to all 
 mining engineers. 
 
 The world's output of petroleum before the war was 
 probably not far short of 350,000,000 barrels of 42 
 gallons, of which about two-thirds were produced in 
 the United States. Dame Nature seems anxious to 
 get rid of it as if it were the offensive exudation of a 
 deep-seated abscess. If nothing could be profitably 
 extracted from it we might well wish it to remain in 
 the bowels of the earth, counting it nothing but a 
 nuisance when it came to the surface. Science can 
 at least claim to have made it useful, seeing that by 
 the process of fractional distillation this disagreeable 
 natural substance can be made to yield in enormous 
 quantities such valuable products as illuminating gas, 
 motor spirit, cleaning spirit, kerosene or lamp oil, 
 paraffin wax, vaseline, and a viscid residue used as 
 fuel. The crude petroleum itself would be useless for 
 any of the purposes to which its derivatives are 
 applied, mainly on account of its highly volatile 
 constituents, which are a source of danger in transport 
 and storage, owing to the inflammable nature of the 
 vapour arising from it. The crude oil is conveyed by 
 pipe lines, in some cases over a distance of several 
 hundred miles, to the refinery, where it is distilled into 
 temperature fractions. The lighter fractions are 
 purified by washing with sulphuric acid, alkali and 
 water ; while sulphur, when it occurs in objectionable 
 quantity, must be removed by means of copper oxide. 
 Among the higher fractions lubricating oil is purified 
 by nitration through animal charcoal. 
 
 The lightest fraction, cymogene, which requires 
 special cooling and pressure for its condensation, is 
 used in ice-making machines. Other fractions 
 obtained are rhigolene, the illuminant used in the pen- 
 tane standard lamp, and as a local anaesthetic in surgery; 
 gasolene, employed for the carburation of water gas 
 for illuminating purposes, for making " air gas," and 
 as a solvent ; ligroin, also a solvent ; benzine or petrol, 
 which supplies us with motor spirit ; and kerosene or 
 lamp oil. Among other products may be mentioned 
 paraffin wax, which, with an admixture of stearic 
 
TO CHEMICAL SCIENCE 55 
 
 acid, is used for the manufacture of candles, solar oils, 
 various grades of lubricants, and vaseline. The 
 quantity of lighter fractions can be increased if 
 desired by the " cracking " of the more complex 
 bodies. 
 
 Astatki, the residue from the distillation of Russian 
 petroleum, yields, on distillation, an excellent illumi- 
 nating gas, besides quantities of benzol, toluol, 
 naphthalene, anthracene, and pitch. 
 
 The shale oil industry, founded by James Young, 
 of Kelly, in 1851, which produces valuable quantities 
 of niuminating and lubricating oils, ammonia, and 
 paraffin wax, depends in a similar manner on scientific 
 operations. 
 
 We claim less for science in the extraction of 
 animal and vegetable oils, which has been 
 practised since time immemorial, but must place to 
 the credit side of the account the responsibility for the 
 differentiation and classification of such oils, the 
 selection of then* most useful applications, with 
 methods of purification and of analysis and valuation. 
 
 Vegetable oils, such as linseed oil a so-called 
 drying oil and turpentine are used as vehicles in the 
 manufacture of paints and oil varnishes. The paint 
 industry has derived great benefit from science in the 
 discovery and application of new pigments, and in the 
 improvement of the older methods of making pig- 
 ments. Turpentine is the starting material for the 
 manufacture of artificial camphor, a synthesis that is 
 a credit to organic chemistry, and although the 
 artificial product cannot as yet be made to compete 
 with the natural substance, it renders good service 
 in keeping down the price of natural camphor, of which 
 the production is practically monopolised by the 
 Japanese. Other vegetable oils, such as olive oil, 
 rape oil, maize oil, and castor oil, are employed as 
 lubricants, whilst some are good illuminating oils. 
 
 The essential oils, of which oil of turpentine is an 
 example, are vegetable oils used in many cases as 
 perfumes. There are three methods of winning the 
 essential oils : (1) by distillation with steam ; (2) by 
 pressure of the plant substance and (3) by extraction 
 
56 WHAT INDUSTRY OWES 
 
 with suitable solvents. Science has entered largely 
 into the essential oil industry by finding the con- 
 stitution of many of the odoriferous principles, which 
 have afterwards been successfully made in the labora- 
 tory from simple materials. In some cases, where the 
 actual substances have not been made, very close 
 imitations have successfully competed with the 
 natural products. Examples of the first are terpiriol, 
 which is the important constituent of Lily of the Valley, 
 and coumarin, New Mown Hay and Jockey Club ; 
 whilst in the second class we have such substances as 
 ionone and nitrobenzene substitutes for essence of 
 violets and oil of bitter almonds respectively. 
 
 SOAP AND CANDLES. 
 
 The soap and candle industries must now be 
 regarded as offshoots of the oil industries. Their origin 
 is remote, but it was not until 1813, when Chevreul 
 published his remarkable researches on the composi- 
 tion of oils and fats, that anything was known of the 
 true nature of the processes involved in their manu- 
 facture. Nowadays the chemist should be in para- 
 mount control of their production. The recovery of 
 glycerine, which at one time flowed into our rivers 
 and streams as a waste product, was a scientific 
 achievement of far-reaching importance, as we have 
 indicated in our remarks on explosives, while its use 
 in medicine is considerable. Incidentally we may 
 mention also that glycerine, mixed with water, 
 prevents evaporation and freezing, and this property 
 finds application in the mechanism of gas meters. 
 
 Both animal and vegetable oils are used in the 
 manufacture of soap and candles. When fats and oils 
 such as tallow, palm oil, olive oil are boiled in large 
 cast iron pans with caustic alkali, they become decom-' 
 posed and yield an alkaline salt of the fatty acid soap 
 and glycerine. The excess of alkali and the glycerine 
 are separated by the addition of a solution of common 
 salt ; the soap, being insoluble in the brine, rises to the 
 top, and is ladled out as a granular curdy mass, run 
 off into frames boxes to cool and solidify. Hard 
 soaps, such as curd and yellow soap, are compounds 
 
TO CHEMICAL SCIENCE 57 
 
 with soda, consisting of about 26 per cent, of water, 
 7 per cent, of soda, and 66 per cent, of fatty acids, 
 with, in the case of yellow soap, a small percentage 
 of resin. Soft soaps are compounds with potash, or 
 potash and soda, with fatty acids derived from drying 
 oils, such as whale and seal oils, linseed, &c. With 
 regard to the water content of hard soap it has been 
 rumoured that, since soaps containing as much as 
 90 per cent, of water have been encountered, it 
 appears to be the aim of some soap makers to cause 
 water to stand upright. 
 
 CANDLES. 
 
 The old tallow dips, prepared by dipping a wick 
 repeatedly into melted tallow, gave rise, on burning, 
 to a pungent substance called acrolein, produced by 
 the decomposition of the glycerine combined in the 
 tallow. Modern candles are without this disadvan- 
 tage, as they contain no glycerine, the free fatty acids 
 from which they are made being liberated from the 
 fat either by the hydrolytic action of sulphuric acid, 
 or by precipitation of the lime salt and its subsequent 
 decomposition with sulphuric acid. The fatty acid 
 e.g., stearic or palmitic acid so prepared is melted and 
 cast round about wicks in moulds of pewter or tin, or 
 sometimes of glass, supported in a wooden frame, the 
 upper part forming a trough. The wicks are arranged 
 taut, the wax is poured in, cooled with water to solidi- 
 fication, and removed as candles. All sorts of waste 
 fats, such as those from wool washing and glue making, 
 are used for making candles, the free acid being 
 extracted by treating the fat with sulphuric acid. 
 
 These industries furnish examples of the utilisation 
 of waste products. The soap used for cleansing 
 purposes in yarn mills is recovered by precipitating 
 the soap from waste liquids with lime, and pressing 
 the precipitate into briquettes, from which sufficient 
 gas can be obtained by distillation to light the mills. 
 Efforts are at the present time being made to recover 
 fat from sewage, mainly for the sake of the glycerine 
 content. 
 
58 WHAT INDUSTRY OWES 
 
 EDIBLE FATS. 
 
 The invention of butter substitutes, now popularised 
 by prevailing conditions and the need for the exercise 
 of economy, is due to the chemist. These substances 
 are commonly made by mixing intimately a solid 
 animal fat, such as stearin, with some vegetable oil, 
 such as cotton seed or cocoanut oil, and milk. The 
 use of solid animal oil for this purpose absorbs some 
 of the raw material formerly available to the soap 
 maker, but the deficiency has been made good by the 
 conversion of the plentiful supply of vegetable oils, 
 such as olive oil, into solid fats by hydrogenation in 
 the presence of finely divided nickel, to which we 
 referred in dealing with that metal. 
 
TO CHEMICAL SCIENCE 59 
 
 CHAPTEB VI. 
 LEATHER, 
 
 UP to the close of the eighteenth century the 
 progress of industry was slow but sure, much of it 
 based undoubtedly 011 the workings of great minds 
 and patient inventive genius, and much again on 
 chance discovery ; but the nineteenth century 
 marked an epoch of development, definitely hastened 
 by the advance made simultaneously in mechanical, 
 physical, chemical, and biological science. Yet when 
 we consider all that was done in ancient times, for 
 example, in the winning of metals, in the dyeing of 
 fabrics, in agriculture and the domestic arts, we 
 are forced to marvel at the vast amount of knowledge 
 and experience, commonly referred to as empiricism, 
 accumulated for centuries before the advent of 
 modern science. We are also convinced that there 
 is no finality in the matter, and that what appears 
 to be ideal to-day will be improved upon to-morrow 
 or the day after. 
 
 An ancient industry is the manufacture of leather, 
 which had seemingly reached the highest degree 
 of efficiency centuries ago if one may judge by exist- 
 ing specimens. To the modern chemist, however, the 
 subject is open to further investigation, involving 
 problems directed to the speeding up of production 
 and decrease of cost without diminishing the quality 
 aims not easily attained, as many have learned from 
 personal experience. In fact, one of our leading 
 authorities has recently expressed the opinion that 
 the science of this important industry is but in its 
 infamy. We are reassured, however, by the statement 
 that the work of Professor H. R. Procter and the 
 Leather Department of the University of Leeds, was 
 largely the factor which rendered it possible for the 
 
60 WHAT INDUSTRY OWES 
 
 nation to supply the enormously increased demand 
 for the military equipment of the Allied Armies, 
 including boots, belts, leggings, saddlery, traces, 
 dressed sheep skins, and numerous minor require- 
 ments, besides the driving belts of the munition 
 factories. With such a demand to meet, the price 
 for the time being of leather for furniture, port- 
 manteaux, gloves, book-binding, and parchment is 
 naturally high. 
 
 The processes whereby raw hides are converted 
 into useful and durable material by treatment with 
 various solutions of substances of animal, vegetable 
 and sometimes mineral origin, are distinctly chemical 
 and biological. They are investigated and explained 
 by research, and modified and superseded by better 
 processes, so far as the increase of knowledge admits, 
 while accidental impurities of a harmful nature in 
 the liquors employed can be traced and their presence 
 avoided. 
 
 The hydrochloric acid washing given to hides 
 that have been unhaired by lime, to free them from 
 that substance, is clearly an operation of a scientific 
 nature, and is also the chemical investigation of the 
 water supply, the quality of the water being important. 
 The science of bacteriology has rendered invaluable 
 assistance in furthering our knowledge of puering 
 the process of softening hides prior to tanning. 
 The changes involved in the old process of treating 
 the unhaired and washed hides with an infusion of 
 dog -dung have been investigated very thoroughly by 
 scientific methods, and have been shown to be the 
 result of bacterial action. Patents, founded on this 
 knowledge, have been taken out for the use of 
 artificial cultures of bacteria instead of the obnoxious 
 infusion referred to. Some of these methods give 
 excellent results, and would doubtless be more gener- 
 ally adopted were it not for the conservatism of the 
 workman and his dislike of the trouble necessitated 
 by a change of procedure. 
 
 The oldest method of treating skin and hide for 
 the purpose of preservation in a flexible state, which 
 consisted in kneading with fatty substances, is of 
 
TO CHEMICAL SCIENCE 61 
 
 historic interest only, though chamois leather is 
 still prepared with oil. Next in chronological order 
 conies vegetable tanning, still very extensively used, 
 the tanning liquor being an infusion of some bark. 
 e.g., of oak or willow. Up to the end of the eighteenth 
 century the prepared hides were simply soaked in a 
 strong infusion of the tan, but about that time Seguin, 
 a Frenchman, introduced a method for soaking the 
 hides successively in tan liquor, or ooze, of increasing 
 strength, the untanned hide going first into the 
 weakest, the completely tanned material being taken 
 from the strongest liquor. By this means thorough 
 permeation by the tan liquor was ensured, and the 
 quality of leather considerably improved. This 
 method was patented in England by William Desmond 
 in 1795. 
 
 Sir Humphry Davy investigated the process of 
 tanning with useful results, indicating the nature 
 of the action between the hide and the tanning 
 material, but only recently has science obtained a 
 hearing in the industry. The reason for this is not 
 far to seek ; the changes involved in tanning are 
 exceedingly complex in character, and depend to a 
 large extent upon the properties of substances in a 
 colloidal condition. Examples of this state are to 
 be found in solutions of gelatine and starch having 
 properties different from ordinary solutions, such 
 as that of setting with the formation of a jelly. 
 The scientific study of the colloidal state is now being 
 more vigorously pursued, and as our knowledge 
 of it increases we may expect further advances in 
 the leather industry. 
 
 Mineral tannages, of which alum was the first 
 known, are also of interest. The " tawing " solution 
 contains alum and common salt, the latter serving to 
 counteract the swelling of the hide produced by the 
 free acid in the alum solution. Salts of the metals 
 iron and chromium, chemically similar to aluminium, 
 have been used for tanning, and although iron salts 
 have no application as tannages at the present time, 
 chrome tanning is a very important industry, founded 
 and reared upon scientific knowledge. Many patents 
 
62 WHAT INDUSTRY OWES 
 
 have been taken out, inchiding those by Knapp in 
 1858, by J. W. later Sir J. W. Swan, by Hein- 
 zerling in 1879 (the first commercially successful 
 process introduced into England) and that by 
 Augustus Schultz, a New York dye works chemist, in 
 1884. Valuable scientific work has also been done in 
 this branch by Eitner and by Procter. A soft and 
 durable leather can be produced which will fix an acid 
 dye without a mordant. 
 
 Leather cloth substitutes for leather, used for 
 covering furniture, for bookbinding, stationery cases, 
 pocket books, and many other useful articles, are 
 also produced under scientific supervision. This 
 industry, however, with that of linoleum and similar 
 material, might have been dealt with as branches of 
 the oil industry had we attempted to deal more 
 comprehensively with that subject. 
 
 Apart from skins and hides there are other products 
 of the slaughter-house, such as horn, blood, hair and 
 bristles, waste wool and the like, from which valuable 
 chemicals such as cyanide are produced. Glue, too, 
 is made from the chippings of hides, horns and hoofs, 
 which are washed in lime-water, boiled, skimmed, 
 strained, evaporated, cooled in moulds, cut into 
 convenient pieces and dried on nets. The processes 
 are nowadays supervised by trained chemists. 
 
TO CHEMICAL SCIENCE 63 
 
 CHAPTER VII. 
 RUBBER. 
 
 RUBBER, formerly commonly called caoutchouc, 
 was originally imported from French Guiana. It 
 was obtained from the Siphonia elastica, and 
 from Brazil, from the Siphonia or Hevea Brazilien- 
 sis, lutea and brevifolia, through the port of Para, 
 and later from the ficus elastica, or india-rubber 
 tree. It was first brought to Europe in the early 
 part of the eighteenth century, but it was many 
 years before its usefulness was realissd. Priestley, 
 the discoverer of oxygen, suggested its use for re- 
 moving pencil marks and, in 1791, Samuel Piat 
 obtained a patent for making waterproof fabrics by 
 dissolving caoutchouc in spirits of turpentine. 
 Hancock, in 1823, and Macintosh followed on similar 
 lines, but the invention of the vulcanising process by 
 Charles Goodyear, whereby the addition of sulphur 
 gave it the consistency of horn, marked the starting 
 point of still greater developments. 
 
 The rubber industry has recognised the importance 
 of scientific control, by botanists and chemists, in 
 planting, cultivation and tapping, with consequent 
 increased yields. Chemists examine the latex, and 
 supervise its drying and preparation for use. The 
 variability of tensile strength is largely dependent on 
 the size of the globules in the latex, which is valued 
 accordingly. No standards of purity have been 
 established, but fine Para is generally considered 
 superior to other varieties. 
 
 For nearly sixty years chemists of all countries 
 have devoted much time and labour to its synthetic 
 production in the laboratory. In 1860 Greville 
 Williams isolated a compound, which he called 
 isoprene, from the products of the distillation o 
 
64 WHAT INDUSTRY OWES 
 
 natural rubber. Nineteen years later, Bouchardat 
 showed that a substance very closely resembling 
 rubber could be reproduced from isoprene by the 
 action of strong hydrochloric acid, and that by the 
 action of heat alone isoprene yielded turpentine. 
 The work of the French chemist was confirmed, in 
 1884, by Professor now SirWilliam Tilden, who 
 suggested a formula for isoprene, which subsequently 
 proved to be correct, and also obtained isoprene from 
 turpentine. Later, these researches formed the basis 
 on which the synthetic rubber industry was founded, 
 though German chemists, who have also done good 
 work in this field of investigation, lay claim to having 
 established principles the credit for which was clearly 
 not due to them. Among other British chemists who 
 have contributed to the investigations on the subject 
 may be mentioned Professor W. H. Perkin, Dr. 
 Strange, and Dr. F. E. Matthews. Two chemically 
 different rubbers are produced : isoprene -caoutchouc 
 and butadiene -caoutchouc. The raw materials, 
 isoprene and butadiene, are obtained from a variety 
 of substances, including turpentine, isopentane (from 
 the rhigolene fraction of American petroleum), coal 
 tar (the material from this source being para-cresol, 
 one of the homologues of carbolic acid), starch and 
 cellulose. The raw material is converted into 
 caoutchouc by methods, involving (i.) polymerisation, 
 by heating under pressure with a suitable substance 
 such as acetic acid, and (ii.) polymerisation, by the 
 action of sodium. The latter method, discovered 
 almost simultaneously by F. E. Matthews in England 
 and Harries in Germany, is the more convenient 
 and gives the greater yield, although the resulting 
 product does not vulcanise so well as that from the 
 former method. All this is progress. As in the case 
 of indigo, science, if successful, will help one form of 
 industry to the detriment of another ; the scientific 
 work on the plantations tends constantly to increased 
 yields and economical working, and the artificial 
 rubber has not as yet displaced the natural either in 
 its properties or in cost of production. 
 
TO CHEMICAL SCIENCE 65 
 
 CHAPTER VIII. 
 MORTAR AND CEMENT. 
 
 THE simplest and most ancient cementitious 
 material is mud, which is still used, reinforced by 
 sticks and grass, by African natives in the construc- 
 tion of their huts. Ordinary mortar is made of 
 water, lime, and sand intimately mixed together. 
 Science has shown that there is no chemical union 
 between the lime and sand ; that the sand acts 
 simply as a diluent, preventing undue shrinkage, 
 which occurs when lime is used alone ; that the setting 
 is due to loss of water, and that the hardening is 
 caused by the gradual formation of interlacing 
 crystals of calcium carbonate, which effectively bind 
 the material into a coherent mass. 
 
 Long before these facts had been established, 
 experience had proved that a pure or " fat " lime 
 produced a better mortar than an impure lime. In 
 the case of hydraulic mortars and cements, however, 
 the knowledge of their structure and action was 
 indefinite until 1887, when the researches of Le 
 Chatelier were published, though a fairly systematic 
 investigation of the nature of hydraulic mortar or 
 rather of the hydraulic limestones employed in its 
 manufacture, was made about the year 1756 by 
 Smeaton, whilst searching for the most suitable 
 binding material for the foundations of the Eddystone 
 Lighthouse, which he had been commissioned to 
 rebuild. He consulted his friend Cookworthy, a 
 chemist, who instructed him in the analysis of lime- 
 stones, and he found that clay was an essential 
 constituent of a hydraulic limestone, the poor lime 
 obtained on burning it being far superior to fat lime 
 for making mortar intended to withstand exposure 
 to water. 
 
66 WHAT INDUSTRY OWES 
 
 Cements are made by heating in a furnace an 
 intimate mixture of limestone or chalk and clay to a 
 temperature at which clinkering takes place. The 
 product is broken up, finely ground, and put upon the 
 market as cement. " Roman " cement was first made 
 by James Parker in 1796, by heating argillaceous lime- 
 stone containing, already mixed, the two necessary 
 ingredients. The manufacture of Portland cement 
 was founded on attempts to imitate Roman cement, 
 using a mixture of lime and clay instead of the 
 argillaceous limestone. Nothing was understood 
 of the why and the wherefore of the process, and 
 often the best part of the product was rejected in 
 the unslakeable portions. Chemical action in the 
 furnace was unthought of, and even when it was 
 evident to scientific men and duly published, con- 
 siderable time elapsed before the manufacturers 
 took advantage of the efforts of science towards the 
 furtherance of their industry. It is now known 
 that chemical action between the lime and the clay 
 in the furnace effects the formation of silicate and 
 aluminate of calcium. When the cement is treated 
 with water, these compounds are decomposed with 
 the production of slaked lime, and the acids derived 
 from silica and alumina. These substances again 
 interact, with the formation of the hydrated silicates 
 and aluminates as interlacing crystals, giving tenacity 
 to the preparation, with the result that first setting 
 and subsequently hardening take place, these 
 phenomena being merely stages in one process. 
 Thus the researches of chemists have established 
 facts which have been most serviceable to the cement 
 maker in increasing the efficiency of his product 
 through the choice and treatment of the best 
 materials. 
 
 We owe more than this, however, to the study 
 of the chemistry of cement. It remained for chemists 
 to show the dangerous effect of certain impurities, 
 such as magnesia, in excess, and sulphates, on the 
 resistance of cement to the attack of water. Such 
 substances must be carefully excluded within well- 
 defined limits. When cement is used to make 
 
TO CHEMICAL SCIENCE 67 
 
 concrete foundations exposed to sea, water, the mass 
 must be either very compact and impervious, or 
 be covered with an impenetrable stone facing, for 
 the reason that sea water contains sulphates and 
 salts of magnesium in plenty, and, consequently, 
 if penetration by the water takes place, the cement 
 decomposes and the life of the structure is corres- 
 pondingly shortened. 
 
 It is obvious that for such a substance, on which 
 the stability of costly buildings and structures so 
 largely depends, the provision of a definite standard 
 specification became a necessity. The British 
 Standard Specification was formulated in 1904 by a 
 sub -committee, appointed by the Engineering 
 Standards Committee, including engineers and con- 
 tractors, chemists, architects, manufacturers, and 
 representatives of official bodies using large quan- 
 tities of Portland cement for public works. The 
 specification provided for both chemical and mechani- 
 cal tests, and, although subsequently modified in 
 the direction of improving the quality of the cement 
 supplied under the specification, remains essentially 
 the same to-day a definitely scientific safeguard 
 accepted alike by producers and users. 
 
 We have indicated how the explanation of scientific 
 phenomena tends to improvement in manufacture, 
 and it is interesting to note that a reason has been 
 advanced for the use of straw in the making of bricks 
 by the Israelites. It is not a suitable binding material, 
 but Acheson has shown that clay is rendered more 
 plastic by the addition of tannin, and that an extract 
 obtained by soaking straw in water produces the 
 same effect. The Israelites complained, therefore, 
 of the hardship of working with less suitable materials, 
 while they had to produce the same tale of bricks. 
 Possibly the use of grass assists in the same way the 
 African natives in making their mud huts. 
 
68 WHAT INDUSTRY OWES 
 
 CHAPTER IX. 
 REFRACTORY MATERIALS. 
 
 A MATERIAL ia termed refractory when it resists 
 the ordinary treatment to which materials of its 
 class are subjected ; it may be a mineral which does 
 not yield readily to the hammer, or an ore not easily 
 reduced. In recent times, however, the term has 
 become specially associated with substances that will 
 resist economically the temperature of a furnace, and 
 the corrosive action of other substances with which 
 they come into contact. Refractoriness may, there- 
 fore, be a vice or a virtue, according to circumstances, 
 and a given material may be refractory in one process, 
 but break down easily if employed in another. 
 
 The increased demand for refractory materials during 
 the war, particularly in the manufacture of steel and 
 glass, has shown the need for further scientific investi- 
 gation. Experiment on the large scale is costly, 
 especially if carried out in an unscientific manner. 
 The help of chemists is therefore essential in deter- 
 mining the composition and the chemical and physical 
 properties of such substances, having in view the 
 purposes to which they are to be applied. The 
 work is not confined to the investigation of known 
 refractories, but is extended to the discovery and 
 utilisation of new refractories to cope with the con- 
 ditions created by their employment in high tempera- 
 ture furnaces. 
 
 Having selected a suitable material, from the 
 chemical point of view, it is necessary to ascertain 
 whether it will withstand, without shrinkage, fusion 
 or softening and consequent deformation the 
 temperature required for the desired reaction. The 
 refractory that will last for ever has yet to be found, 
 but that with the longest life is the most economical, 
 
TO CHEMICAL SCIENCE 69 
 
 provided the saving effected by the increased length 
 of life renewals being less frequently required 
 plus the saving of time and labour, in more continuous 
 running of the furnace, is proportionate to any 
 additional cost. The subject has long been treated 
 more or less scientifically, the older refractories 
 being classified into acid, basic, and neutral materials^ 
 As examples of the acid class we have fire-clays, such 
 as ganister, the highly siliceous material used for 
 lining acid Bessemer converters ; in the basic class, 
 such substances as lime, magnesia, and calcined 
 dolomite ; while among the neutral refractories we 
 may include gas carbon and graphite. These mate- 
 rials have proved eminently suitable for some pur- 
 poses, but with the use of the electric furnace we 
 require substances still more refractory, and in recent 
 years science has provided a number of them. 
 
 Carborundum, the extremely hard and refractory 
 carbide of silicon, was first made in 1891 by Acheson, 
 who obtained it by heating graphite with sand in the 
 electric furnace, and it is now employed as a refractory 
 lining for such furnaces, besides being useful as an 
 abrasive. It has also been incorporated with cement 
 to give grip to surfaces, as on staircases subjected to 
 considerable wear. Other modern refractories are 
 alundum fused aluminium oxide silicon, fused 
 silica, zirconia, and artificially made graphite. Cru- 
 cibles of graphite, intimately mixed with sufficient 
 clay to give the mixture coherence, are far preferable 
 for many purposes, and much more durable than those 
 made of clay alone. 
 
 F 2 
 
70 WHAT INDUSTRY OWES 
 
 CHAPTEB X. 
 GLASS AND ENAMELS. 
 
 THE manufacture of glass dates from the first 
 period of Egyptian history. Egypt, the instructor 
 of the world in so many arts, possessed in very early 
 times craftsmen skilled in making, blowing, colour- 
 ing and cutting this most remarkable and useful 
 material. The industry survived through the vicis- 
 situdes of the country until the time of Tiberius 
 (A.D. 14-41), who brought Egyptian glass workers to 
 Rome, where the art nourished until the decline of the 
 empire, during which the principal centre of manu- 
 facture was transferred to Byzantium. The value 
 attached to glass by the ancients is indicated by the 
 circumstance that the industry was always supported 
 and encouraged by the most powerful and influential 
 rulers, migrating with their power from one country 
 to another. However, at the time of the fall of 
 Constantinople it had become established in various 
 centres, of which the chief was Venice, where it soon 
 attained such proportions as to give occupation to 
 over 8000 persons. 
 
 In the Middle Ages the industry was developed in 
 Germany and Bohemia, especially in the latter country , 
 which, owing to the native supply of pure quartz, 
 ultimately superseded Venice as the source of the finest 
 glass. Inl870 glass making gave employment to 30,000 
 workers in Bohemia. The invention of glass mirrors 
 has been attributed to the Germans, the original 
 method being to back the glass with polished metal. 
 Glass was first used for windows in England about 
 the end of the eleventh century, and was made here 
 in the fifteenth, but with little success until about 
 1557, when French artisans were employed in London. 
 In 1670 Venetian workers were brought over to make 
 
TO CHEMICAL SCIENCE 71 
 
 the heavier and finer kinds, and in 1771 the industry 
 became more firmly established by the formation of 
 the British Plate Glass Company, whose successors 
 are still in existence at St. Helens. 
 
 The scientific study of glass was first made on the 
 physical side, its transparency, permanence, and the 
 absence of crystalline structure with consequent 
 birefringence, combining to render it an almost ideal 
 material for the construction of the essential parts of 
 optical instruments. In fact, the science of optics, 
 with its manifold applications to spectacles, micro- 
 scopes, telescopes and spectroscopes, owes its exist- 
 ence to our possession of glass. The first investiga- 
 tions in the chemistry of the subject were made with 
 a view to the improvement and better adaptation of 
 glass to optical purposes. Up to 1829 the only 
 varieties of optical glass were soda-lime or crown 
 glass, potash-lime or Bohemian glass, and potash-lead 
 or flint glass, also known as crystal or strass, these 
 being made from mixtures of the silicates of the 
 metals indicated. Before that year Fraunhofer and 
 Guinand had made experiments modifying the com- 
 position of crown and flint glasses, and had produced 
 compound lenses with a fair approach to achro- 
 matism. In 1829, however, Dobereiner produced 
 glasses containing barium and strontium, metals 
 closely allied to calcium, the metal contained in lime, 
 and in 1834 Harcourt, in England, commenced a long 
 series of researches on the production of new glasses, 
 which although the positive results obtained were 
 of small value established principles subsequently 
 turned to good account in the manufacture of special 
 kinds for thermometers, laboratory apparatus, lamp 
 chimneys, optical instruments, and many other 
 important articles. The next advance, an epoch- 
 making one, was begun about 1880, when Schott, a 
 trained chemist, the son of a Westphalian glass maker, 
 was encouraged by Abbe to search for new and 
 better optical glass. His knowledge of mineralogy 
 served him well, for instead of proceeding laboriously 
 along the lines of methodical research, he took almost 
 a direct road to the desired goal, producing glass con- 
 
72 WHAT INDUSTRY OWES 
 
 taining boric and phosphoric oxides with alumina and 
 baryta. Microscopes designed for these new glasses 
 proved perfectly achromatic, and in every way 
 superior to the older kinds ; and this striking advance 
 has doubtless contributed enormously to the useful- 
 ness of the microscope, and of the microscope to 
 industry generally. 
 
 Schott next turned his attention to the solution of 
 the problems of thermal expansion and volume tem- 
 perature hysteresis of glass. Owing to its low thermal 
 conductivity it is important that glass intended to 
 withstand sudden changes of temperature should 
 have a thermal expansion as slight as possible, in 
 order to hold against the strain set up by unequal 
 temperature changes, and so that the risk of cracking 
 may be minimised within reasonable limits ; the 
 range of temperature change varying inversely as the 
 thermal expansion. Pursuing his investigations, 
 Schott produced borosilicate glasses with exceed- 
 ingly low coefficients of expansion, and capable of 
 resisting a sudden temperature change of over 190 
 deg. Cent., whereas the ordinary Bohemian glass 
 would scarcely withstand a change of much over 90 
 deg. The borosilicate glasses have therefore been of 
 service for the construction of incandescence gas 
 chimneys, and also of apparatus for laboratory use ; 
 their slight solubility in chemical reagents constitut- 
 ing an additional advantage. 
 
 When a thermometer made of ordinary glass is heated 
 to a temperature much above that of the air the glass 
 bulb, on cooling, does not return immediately to its 
 original volume, and may take months or even years 
 to do so. Consequently if the bulb, before it has re- 
 gained its original volume, is surrounded by melting 
 ice, the thermometer will not register the true melting 
 point, but a point, varying with the thermometer, from 
 0.5 to 1 deg. Cent, below the correct temperature ; 
 and lower temperatures in general will not be regis- 
 tered correctly until the bulb has regained its original 
 volume. This defect was largely overcome by the 
 results obtained by Schott, whose Jena normal glass 
 16 111 and Jena borosilicate glass 59 111 , when used for 
 
TO CHEMICAL SCIENCE 73 
 
 thermometers, show a zero depression of only about 
 0. 05 deg. Cent, after heating to 100 deg. Cent. Owing 
 to their infusibility, glasses of this type can also be 
 used for nitrogen-filled thermometers, registering up 
 to about 575 deg. Cent. 
 
 The list of new and useful scientific products might 
 be much further extended if we were to deal with the 
 subject more thoroughly, but it would be regarded as 
 an oversight if we omitted to mention fused silica 
 glass, a comparatively recent invention. From pure 
 quartz worked in the oxy-hydrogen flame excellent 
 glass is produced, having the property of withstanding 
 a sudden change of temperature of over 1000 deg. 
 Cent. Being highly resistant to chemical action, it 
 useful in the laboratory for many purposes for 
 which platinum was formerly employed. 
 
 Until the outbreak of war the production of glass- 
 ware for use in chemical investigations was almost 
 exclusively in the hands of Germany and Austria. 
 Stocks were becoming speedily exhausted and the 
 position would have become serious for many impor- 
 tant industries if British chemists had not promptly 
 taken the matter in hand. They had not merely to 
 imitate glasses previously imported, but to find 
 substitutes for certain ingredients of batch mixtures, 
 notably potash, for which also we had hitherto been 
 dependent on Germany and of which supplies were 
 running low. The work of Professor Herbert Jackson*, 
 in conjunction with the Glass Research Committee of 
 the Institute of Chemistry, was especially successful, 
 and, with the co-operation of a number of well-known 
 firms, laboratory vessels, such as beakers and flasks, 
 and all ordinary forms of apparatus are now produced 
 in this country, having qualities in some respects 
 superior to those of enemy origin. In some cases, 
 perhaps, the products have not quite the same finish 
 as those of the experienced German workers, but we 
 are convinced that the defects are not radical, and 
 that given time, the British makers will not only equal, 
 but excel the German in both quality and technique. 
 
 * Now Sir Herbert Jackson, K.B.E. 
 
74 WHAT INDUSTRY OWES 
 
 In addition to the needs of the laboratory, many other 
 kinds of glass were required, and the work was 
 extended to the investigation of over forty varieties 
 for which formulas have been supplied to approved 
 firms. With shortage of labour and other economic 
 difficulties, firms have undertaken with remarkable 
 energy new branches of work which it is hoped they 
 will be able to retain, in the future, in the face of 
 competition from our quondam enemies. 
 
 Yet another problem has been successfully tackled 
 by Professor Jackson for the Ministry of Munitions, 
 viz., the treatment of clay used for making vessels 
 employed in glass production. 
 
 For the production of optical glass essential to the 
 services, we, fortunately, had well-established manu- 
 facturers, by whose praiseworthy endeavours the 
 output has been sufficient to cope with the greatly 
 increased demand. Professor Jackson has supplied 
 formulas for batch mixtures for several important 
 varieties not hitherto made in this country. The 
 difficulty of securing supplies of suitable sand had 
 also to be faced, and our mineralogists and chemists 
 devoted attention to this question, with satisfactory 
 results, the report of Dr. Boswell, of the Imperial 
 College of Science and Technology, indicates that we 
 possess natural resources which can be utilised by our 
 manufacturers to their advantage. Research work 
 on refractories and electric furnace methods is also 
 in progress at the National Physical Laboratory. 
 
 In the course of time an enterprising firm, with the 
 aid of chemists and from indigenous sources, produced 
 supplies of potash of high quality in sufficient bulk 
 for the imperative requirements of glass makers, and 
 this factor was of no small consequence, since it is 
 admitted that for certain glasses potash is practically 
 indispensable. 
 
 From the foregoing, it is evident that in spite of 
 the antiquity of the industry, and the fact that good 
 glasses for ordinary and ornamental purposes were 
 produced independently of modern science, many 
 special glasses owe their origin entirely to scientific 
 investigation. It is not too much to say that on the 
 
TO CHEMICAL SCIENCE 75 
 
 possession of such glasses in time of war may depend 
 the fate of many a good ship and many a good man. 
 Who can say, then, how great is the debt of the 
 industry to science and of the country to both ? 
 
 ENAMELS. 
 
 The art of enamelling is of remote origin. We 
 have already referred to its application to pottery by 
 the Chinese. It was practised also by the Egyptians 
 and Etruscans, passing in the course of time to the 
 Greeks and Romans ; but we propose to deal more 
 particularly with the enamelling of metals, which 
 appears to have been invented in Western Asia 
 and to have traversed Europe in the early centuries 
 of the Christian era. The history of the subject is 
 of absorbing interest to those who regard it as an art, 
 and much may be gleaned from BushelFs work on 
 " Chinese Art," published by the Board of Education. 
 The Chinese give the credit for its discovery to 
 Constantinople ; the similarity between the methods 
 of the Chinese and the Byzantine enamellers is held 
 to support this opinion. We are concerned here, how- 
 ever, with the utilitarian rather than the artistic 
 applications of enamels. We use them in the manu- 
 facture of badges, watch and clock faces, and on 
 surfaces exposed to weather (advertisements), on th 
 blades of exhaust fans, on baths and domestic utensils, 
 and on vessels employed in chemical industry. 
 
 An ordinary enamel may be prepared from common 
 glass fused with lead oxide, and rendered opaque by the 
 addition of oxide of tin. Colours may be produced 
 by the addition of other metallic oxides. Thus, from 
 copper we obtain green ; from iron or gold, red, and 
 from cobalt, blue. Small quantities of manganese 
 dioxide give us a fine violet colour and larger quantities 
 black. For the production of good colours, the 
 purity of the raw materials is of the first importance, 
 and the enamel maker looks, therefore, to the help 
 of the chemist to ensure satisfactory results. If an 
 enamel is to be pigmented with copper, the presence 
 of this metal in the raw material will not be objection- 
 able if its degree of oxidation is the same as that of the 
 
76 WHAT INDUSTRY OWES 
 
 pigment used. If the enamel is to be coloured green 
 with cupric oxide and that substance is present in the 
 lead oxide used, the impurity is of small consequence ; 
 but if the enamel is to be coloured yellow with anti- 
 mony oxide, the green produced by the copper 
 impurity will spoil the effect. The presence of small 
 quantities of ferric oxide in the lime will modify the 
 green produced by copper oxide, and is undesirable 
 unless it be required to tone the green colour, when 
 it can be added to materials originally free from this 
 substance. In any case, the quantity of impurity 
 should be estimated and due allowance made for 
 its effect. Much may depend on the method of 
 preparation of the pigment. For instance, cupric 
 oxide may be prepared by roasting copper filings in 
 air, but the product will not yield nearly such good 
 colours as the oxide chemically prepared from pure 
 copper ; and again, the blue colour produced from 
 commercial cobalt compounds is greatly inferior to 
 that obtained from chemically prepared cobaltous 
 silicate. 
 
 Of the methods of preparing chemical and heat resist- 
 ing enamel for industrial plant little is common know- 
 ledge. In some cases the coating consists of two 
 layers, the first being devised to bind with the metal 
 and act as intermediary between the metal and the 
 finishing enamel. Having in view the uses to which 
 such vessels are put, there is plenty of room for 
 further investigation, particularly on the coefficients 
 of expansion of various metals and alloys and the 
 relation of such physical considerations to the 
 composition of the enamels employed. The surface 
 remains good until a craze appears, but once liquid 
 gets to the metal the vessel begins to lose its coating. 
 It is reassuring to know that chemical firms of long 
 standing find British enamel ware, such as evaporating 
 pans, at least as satisfactory as that from Germany, 
 though our manufacturers, as is often the case with 
 other commodities, have been less inclined to put 
 themselves about to supply special requirements, for 
 instance, with regard to the shapes and sizes of the 
 vessels required. 
 
TO CHEMICAL SCIENCE 77 
 
 CHAPTER XI. 
 POTTERY AND PORCELAIN. 
 
 THE manufacture of pottery is yet another industry 
 which has been handed down from veiy early times. 
 Pliny attributed the craft, in which the Greeks and 
 Etruscans excelled, to Coraebus, an Athenian, but 
 obviously it was of far greater antiquity, the potter 
 being frequently referred to in ancient Egyptian 
 records to symbolise the Creator of man. The 
 earthenware of the Greeks and Romans was unglazed 
 and porous, but they rendered their vessels impervious 
 by covering them with wax, tallow and bitumen. 
 The invention of porcelain is generally credited to 
 the Chinese. It is mentioned in books of the Han 
 dynasty, the earliest date suggested being about 
 185 B.C. Its origin has been attributed to attempts 
 made to imitate glass imported from Syria and 
 Egypt, and by some it is supposed to have been 
 discovered accidentally by alchemists in their 
 search for the philosopher's stone. The industry 
 was started in Japan before 27 B.C., and found 
 its way from the Far East to Persia, where it is 
 known as chini, coming to us, in the course of time, 
 through Arabia, Spain, Italy and Holland, the 
 potteries of Lambeth being founded by men from 
 Holland about 1 640. Porcelain was made in France, at 
 St. Cloud, towards the end of the seventeenth 
 century, and in nearly all European countries in 
 the eighteenth century. 
 
 We can only marvel that such porcelain as, say, 
 that of the Ming Dynasty (1368-1643), with all 
 the technique involved in the selection of materials 
 and its treatment, the craftsmanship, colouring and 
 glazing, was produced before science, as we now use 
 the term, had any voice in such matters. The 
 
78 WHAT INDUSTRY OWES 
 
 Chinese hard paste porcelain consisted of kaolin 
 in a pure and very finely divided state, and petuntzo 
 (finely ground felspathic stone) ; and the glaze was 
 made from selected petuntze mixed with specially- 
 prepared lime. 
 
 One of the first European makers of fine porcelain 
 of whom we have records was Botticher, a Saxon 
 chemist who was placed in charge of the Meissen 
 factory, established in 1710, the methods employed 
 being kept secret. Pott, a Prussian chemist, en- 
 deavoured to compete with him, and although his 
 efforts were not successful, his researches on materials 
 likely to be useful in porcelain manufacture gained 
 for the industry some helpful knowledge. About 
 the middle of the eighteenth century 700 men were 
 employed at Meissen, but in the meantime Stolzel, 
 who escaped from the factory about 1720, founded 
 the Austrian industry at Vienna, where 500 men 
 were employed in 1785. Mention should also be 
 made of the circumstance that William Cookworthy, 
 chemist of Plymouth, to whom we have already 
 referred in connection with cement, found kaolin 
 at Tregonning, near Helston, and took out a patent 
 in 1768, which he worked at Plymouth for two or 
 three years before establishing a factory at Bristol. 
 We must admit that the claims of science so far were 
 slender, and we do not propose to pursue the history 
 of the subject further ; but science required for her 
 own purposes porcelain resistant to chemical action, 
 heat, and variations of temperature. The production 
 of Royal Berlin basins and crucibles for the laboratory 
 could only be secured by careful selection and 
 utilisation of the most suitable materials and much 
 painstaking experiment. Science examined the pro- 
 cesses employed and explained the changes involved, 
 while one notable achievement, viz., the discovery 
 of means for measuring high temperatures, found 
 direct application in the industry. The temperature 
 of kilns is a factor of no little importance, and is 
 usually determined by cones made of oxides of iron, 
 aluminium, and silicon. The softening points of 
 the cones are known with reasonable accuracy a 
 
TO CHEMICAL SCIENCE 
 
 series of thirty-six allowing for the observation of 
 sufficient range of temperature in porcelain burning. 
 As the temperatures exceed 1000 deg. Cent, ordinary 
 thermometric methods are not applicable. The 
 series of cones could only be constructed and stan- 
 dardised with the aid of physical science, which has 
 provided Le Chatelier's thermo-electric pyrometer, 
 Callendar's platinum resistance thermometer and the 
 Fery radiation pyrometer. Their use in the stan- 
 dardisation of the cones, however, is, of course, 
 insignificant compared with their use in metal- 
 lurgical operations. 
 
 For supplies of porcelain for laboratory pur- 
 poses this country has hitherto been mainly de- 
 pendent, as in the case of glass, on Germany. Our 
 chemists have taken the matter in hand, however, 
 and remarkable progress has been made by several 
 British manufacturers. Research on the subject of 
 hard porcelain is progressing, and there is good ground 
 for hoping that this branch of the industry will be 
 retained here in the future. 
 
 The danger to workers of lead oxide as a constituent 
 of glazes for earthenware has also provided a problem 
 for chemists. The employment of lead silicates 
 instead of oxide, as suggested by Thorpe and Sim- 
 monds, is less harmful ; and the lead glazes have 
 been largely superseded in recent years by mixtures 
 containing silica, alumina, potash, and soda, with 
 about 10 per cent, of boric acid to increase the 
 fusibility. Where lead is an essential constituent 
 it is applied in the form of silicate. 
 
80 WHAT INDUSTRY OWES 
 
 CHAPTEB XII. 
 CHEMICAL PRODUCTS. 
 
 IN our second chapter we have dealt with the 
 heavy chemicals and alkalies, and we will proceed 
 now to consider the production of other chemical 
 substances of value in industry, or useful for 
 domestic, medicinal, scientific, or other purposes. 
 The importance of this branch is so wide and 
 fundamental that it is not too much to say that 
 industry as a whole is largely dependent on an 
 adequate supply of chemical products. The field 
 is so great that we cannot attempt to indicate all 
 or nearly all the substances coming under this head, 
 but we will choose a few examples of different types, 
 all rendered available by scientific methods. 
 
 Acids. Certain acids, such as tartaric, citric, 
 lactic, oxalic, formic, salicylic, benzoic, acetic, 
 hydrofluoric, boric, and arsenic acids are not prepared 
 on a scale comparable with that of sulphuric, hydro- 
 chloric, and nitric, but their value in technical 
 operations and for other purposes warrants their 
 industrial production in a condition more or less 
 pure, according to circumstances. Tartaric and 
 citric acids, from vegetable sources, and lactic acid 
 of animal origin, are used in calico printing. The 
 first is an ingredient of baking powders and effer- 
 vescing medicines, such as seidlitz powders, and 
 the second is used in the production of summer 
 beverages. Oxalic acid, -which is prepared by heating 
 sawdust with a mixture of caustic potash and soda 
 in the presence of air, is also used in calico printing, 
 and its acid salts are valuable as detergents, under 
 the name of salts of sorrel or salts of lemon. Formic 
 acid is useful in dyeing and tanning, and it is interest- 
 ing to note that it was formerly obtained by distilling 
 
TO CHEMICAL SCIENCE 81 
 
 red ants, but is now made by heating caustic soda 
 with carbon monoxide under pressure. Salicylic 
 acid, which is prepared from phenol, is used in the 
 production of various drugs, of which aspirin is an 
 example, and is employed as an antiseptic. Benzoic 
 acid, from toluene, finds application in the manu- 
 facture of dyes and as a preservative ; acetic acid 
 in bleaching, dyeing, and calico printing, and in 
 the manufacture of artificial vinegar. Hydrofluoric 
 acid, which is obtained by the action of sulphuric 
 acid on fluorspar, comes on the market as an aqueous 
 solution in gutta-percha bottles, and is used for 
 etching glass as well as for antiseptic purposes. 
 Boric acid, from mineral sources, is valuable as a 
 constituent of various kinds of glass, and is used as 
 an antiseptic and a food preservative. Arsenic 
 acid is employed in dyeing and in the preparation 
 of certain aniline colours. 
 
 Bases. Among the common bases we have caustic 
 potash, caustic soda with which we have already 
 dealt strontium hydroxide, and magnesia, alkaline 
 metallic oxides capable of neutralising acids with the 
 production, by double decomposition, of salts and 
 water, the metals replacing the hydrogen in the 
 acids. Caustic potash is prepared either by electro- 
 lysis of the chloride or by the action of lime on a- 
 solution of potassium carbonate, that salt being 
 obtained from the chloride by a modification of the 
 Leblanc process or by a method identical in principle 
 with the ammonia-soda process, in which trimethyl- 
 amine of which something will be said later 
 takes the place of ammonia. For some purposes 
 the cheaper base, caustic soda, is equal in efficiency 
 to the more expensive but more powerful potash ; 
 but for others the latter is more economical for 
 instance, in the production of oxalic acid from saw- 
 dust on the large scale. When caustic soda alone 
 is used, the yield of acid is not more than a third of 
 that obtained by the use of caustic potash or of a 
 mixture of potash and soda. On the other hand, 
 in the analysis of flue gases, a valuable check on 
 fuel economy, a soda solution of pyrogallic acid is 
 
82 WHAT INDUSTRY OWES 
 
 a very much more rapid and efficient absorbing 
 reagent for oxygen than a potash solution of the 
 same. Caustic potash decomposes most metallic 
 salts, and at a high temperature acts with energy 
 on many substances. It is employed in numerous 
 industrial operations, and is ordinarily used for the 
 manufacture of soft soap, in which it is combined 
 with the fatty acids derived from the drying oils, 
 such as linseed, whale, and seal oils. 
 
 Strontium hydroxide, prepared mainly from the 
 mineral sulphate, is largely used in the extraction 
 of the uncrystallisable sugar from molasses. The 
 native carbonate requires a higher temperature for 
 calcination to oxide than does calcium carbonate to 
 lime. However, in certain sugar works, where fuel, 
 including exhausted cane, is cheap, this process is 
 used for the production of the material. 
 
 The use of magnesia in the ammonia-soda process, 
 and also as a refractory material, has already been 
 mentioned. Considerable quantities are consumed 
 in medicine as an anti-acid. 
 
 Salts. The salts of technical importance are very 
 numerous. Those of sodium, on account of their 
 cheapness, easy solubility in water, and comparative 
 harmlessness, are in constant use in many in- 
 dustries, and are often interchangeable with 
 potassium salts ; but in some cases the special 
 properties of the latter yield better products for 
 manufacturing purposes. Potassium permanga- 
 nate and chlorate can be crystallised better 
 than the corresponding sodium salts, and are 
 therefore obtainable in a higher state of purity. 
 Potassium nitrate is used in the manufacture of 
 ordinary gunpowder, whereas the use of sodium 
 nitrate would be impracticable on account of its 
 ready absorption of atmospheric moisture. Potassium 
 sulphate, a constituent of ordinary alum, occurs as 
 the mineral kainite, and is valuable as a fertiliser. 
 Potassium f errocyanide and bichromate are ingredients 
 in the production of certain pigments, and the latter 
 finds employment in tanning and photography, as 
 well as in the cells of bichromate electric batteries. 
 
TO CHEMICAL SCIENCE 83 
 
 Both these salts are now largely replaced by the 
 cheaper sodium compounds, owing to the stoppage 
 of supplies from Germany. A mixture of sodium 
 and potassium cyanides obtained by heating potassium 
 ferrocyanide with metallic sodium is used in the 
 Mac Arthur -Forrest gold extraction process. Sodium 
 nitrite and hypochlorite are largely used in the pro- 
 duction of dyestuffs, and, indeed, the fact that the 
 former was hitherto obtained almost exclusively 
 from Germany formed no small obstacle to the 
 manufacture of certain important dyes in this country. 
 Sodium thiosulphate hypo is used in bleaching 
 as an antichlor and in photography as a solvent for 
 silver halides. Sodium silicate water glass is used 
 for preserving eggs and also for protecting carbonate 
 stone buildings from the action of weathering. 
 
 Ammonium sulphate we have already mentioned 
 as an artificial manure. The chloride is used in 
 soldering, and its solution forms the electrolyte in 
 Leclanche cells. The nitrate is the source of ** laugh- 
 ing gas," and the commercial carbonate is commonly 
 the principal constituent of " smelling salts." 
 
 Mention must also be made of certain peroxy 
 compounds, some of which have attained considerable 
 technical importance in comparatively recent times. 
 Sodium peroxide is obtained by the action of hot air on 
 sodium contained in aluminium trays. The per- 
 carbonates and persulphates of sodium, potassium, 
 and ammonium are prepared by methods of electro- 
 lysis. Barium peroxide is made by heating the 
 oxide to a dull redness in dry air, free from carbon- 
 dioxide, and is used in the manufacture of hydrogen 
 peroxide, which, as are other peroxy compounds, is 
 largely applied as a bleaching agent for cellulose 
 materials. 
 
 The salts of barium and strontium are very useful 
 in pyrotechny, the former for producing green and 
 the latter red light. Magnesium sulphate is Epsom 
 salts. Mercury salts, including calomel, are also em- 
 ployed in medicine. Mercuric chloride or corrosive 
 sublimate is an excellent antiseptic, and the fulminate 
 is a useful explosive. Zinc chloride is used for the 
 
 Q 
 
84 WHAT INDUSTRY OWES 
 
 destruction of insects and parasites, and other zinc 
 compounds are of medicinal value. Gold, silver, 
 and platinum salts are extensively used in photo- 
 graphy, and copper, tin, and antimony salts in 
 dyeing and calico printing. Copper salts are also 
 important in the Deacon chlorine process, in electro - 
 typing, in the manufacture of pigments, and the 
 protection of wheat from smut. Lead carbonate, 
 or white lead, is used in large quantities in paint 
 manufacture, and the azide is an explosive body, 
 which may be employed in percussion caps. Bismuth 
 and iron salts find good use in medicine, the sulphate 
 of iron being also useful in gold extraction. 
 
 Solvents. Water, the commonest and most useful 
 solvent, cannot be discussed here for the obvious 
 reason that under ordinary conditions it is not a 
 chemical product from our point of view. Water 
 purified by distillation, however, is a commercial 
 article, and might perhaps be included. Among 
 inorganic solvents, mention must be made of ammo- 
 niacal copper solution for cellulose, and sulphur 
 chloride, which is prepared by the direct union of 
 the elements and is a valuable solvent for sulphur, 
 being largely employed in vulcanising rubber. The 
 common acids, such as nitric, sulphuric, and hydro- 
 chloric, are excellent solvents for metals and oxides, 
 but the solutions so obtained are not simple, the 
 original metal or oxide not being recoverable by 
 merely evaporating the solvent. Alcohol, or spirits 
 of wine, prepared by the rectification of fermented 
 liquor, is a valuable solvent in many ways, such as, 
 for instance, the purification of certain organic pro- 
 ducts by crystallisation from alcoholic solution. 
 
 In manufacturing processes, substances, such as 
 fatty oils, rubber, and sulphur, which are insoluble 
 in water, are frequently required in the form 
 of a solution, and it rests with the chemist to 
 discover the best solvents for such substances and 
 the methods of preparing and applying them. 
 Carbon disulphide, a volatile, poisonous, highly 
 refracting liquid, heavier than water, was discovered 
 in 1796 by Lampadius, who obtained it by distilling 
 
TO CHEMICAL SCIENCE 85 
 
 iron pyrites with carbon. As ordinarily met with 
 it has a most obnoxious smell, but when pure the 
 odour is ethereal and not unpleasant. It occurs 
 in the products of the destructive distillation of coal, 
 but is manufactured mainly by the direct union of 
 charcoal or coke with sulphur in retorts or in the 
 electric furnace. Its uses are many ; it dissolves 
 sulphur, gums, rubber, phosphorus, resins, essential 
 oils, iodine, and alkaloids. It is used sometimes for 
 the extraction of fatty oils remaining in the residue 
 after crushing seeds, being subsequently removed by 
 distillation and used again. A solution of sulphur 
 in carbon disulphide is used for the vulcanisa- 
 tion of rubber. Its poisonous action has been 
 utilised for destroying blight in grain without ill 
 effects except to the blight ; and potassium thio- 
 carbonate a compound of carbon bisulphide and 
 potassium sulphide is destructive to insects which 
 infest vines. On account of its high index of refrac' 
 tion, hollow glass prisms filled with carbon disulphide 
 are employed in spectroscopy. A solution of iodine 
 in carbon disulphide is of use in certain physical 
 experiments, for the reason that such a solution is 
 opaque to rays of light, while it transmits heat rays 
 freely. Lastly, we may mention that from carbon 
 disulphide and chlorine is obtained carbon tetra- 
 chloride, a solvent for fats, which is also employed 
 in the production of certain dyes, and being non- 
 inflammable, serves a useful purpose in fire -extinguish- 
 ing apparatus. 
 
 Among the organic solvents are several that are also 
 anaesthetics. Chloroform was discovered simultane- 
 ously by Guthrie, an American, and Souberain, a 
 Frenchman, in 1831, and was first employed as an anae- 
 sthetic by Lawrence in London, and Simpson in Edin- 
 burgh, in 1847. Itis prepared on the large scale by the 
 action of chloride of lime on alcohol or acetone, the 
 product being a valuable solvent for fatty oils, india- 
 rubber, alkaloids, resins, and other substances. 
 Prepared by the above process, however, it contains 
 highly poisonous impurities, which are gravely 
 detrimental to its use as an anaesthetic, for which 
 
 G 2 
 
86 WHAT INDUSTRY OWES 
 
 purpose it is obtained by distilling chloral resulting 
 from the action of chlorine on alcohol or its hydrate 
 with caustic soda, the final product being sufficiently 
 pure. 
 
 Ether, another solvent, also an anaesthetic, was 
 known in the sixteenth century, and described by 
 Valerius Cordus, a German physician. It was 
 prepared by the action of sulphuric acid on alcohol, 
 and in the early part of the eighteenth century was 
 employed as a mixture with alcohol, under the 
 name of Hoffmann's Anodyne, to allay pain. Its 
 use as an anaesthetic was discovered by Charles 
 Jackson, of Boston, in 1842. The most economical 
 method of manufacture is the continuous process, 
 devised by Boullay. 
 
 Acetone, a valuable solvent for oils, and employed 
 largely in the manufacture of explosives, is found 
 in the free state in the products of the destructive 
 distillation of wood, and is obtained by the dry 
 distillation of acetate of lime, which substance is 
 also produced from pyroligneous acid. 
 
 Fine Chemicals. The many substances we have 
 mentioned under the heading of chemical products, 
 represent only a very small proportion of those in 
 common use, and do not include all that are employed 
 in the laboratory, or those at present of purely 
 scientific interest, which are very numerous. We say 
 " at present " purposely, for no one can tell how soon 
 they may find practical application. The value of 
 " research for its own sake " has already been shown 
 in the many examples we have cited of the discovery 
 of elements and compounds, at first merely regarded 
 a,s scientific curiosities, but sooner or later proved to 
 be of incalculable importance to industry and to the 
 world. So much depends on the accuracy of 
 analytical results, that an adequate supply of 
 chemicals in a sufficiently pure state to be used as 
 reagents is an essential requirement in all laboratories. 
 The statement should be too obvious to mention, but 
 it must be remembered that we buy and sell on 
 analytical data ; we check and control vast technical 
 operations on such data, and must be able to rely on 
 
TO CHEMICAL SCIENCE 37 
 
 sound reagents in most chemical investigations. 
 German fine chemicals have enjoyed a reputation for 
 purity, but of chemicals generally, apart from dye- 
 stuffs, we produce the bulk of our own requirements ; 
 our export trade has been greater than that of our 
 continental competitors, and there is no doubt that, 
 with increased scientific control and care, we can 
 manufacture products of equally high standard. 
 
 A number of concerns of established repute are now 
 energetically developing the fine chemical industry. 
 The processes of manufacture and purification call 
 for the services of highly trained chemists, of whom 
 the supply will certainly be forthcoming as the demand 
 for them increases. 
 
 A pamphlet prepared by a special committee 
 appointed by the Councils of the Institute of 
 Chemistry and of the Society of Public Analysts, was 
 issued early in 1915, giving details of the tests for 
 purity of a number of important analytical reagents. 
 This provides a standard for the manufacturers who 
 will still continue to make products of other grades 
 for various uses, while producing the fine chemicals 
 up to the specification standard at a higher cost, 
 which the consumer is always willing to pay. For 
 one example out of many, sulphuric acid for many 
 technical purposes is highly impure. In some cases 
 the impurities are substances which do not affect the 
 behaviour of the acid and its suitability for the purposes 
 for which it is required. A purer acid is made for 
 general laboratory use ; but for good analytical work 
 the acid must be free from lead, calcium and other 
 metals, from arsenic, selenium, nitrogen and halogen 
 ompounds, and from reducing substances, and should 
 leave no solid residue on evaporation to dryness. 
 Tests are prescribed whereby such impurities may 
 be detected, but it is most advantageous to be able 
 to secure reliable supplies without the necessity of 
 applying them, and possibly being obliged to purify 
 the substances in the laboratory before using them. 
 The purification of sulphuric acid on the small scale 
 is an expensive, difficult, and tedious operation. It 
 is a hopeful sign therefore that a number of our well- 
 
88 WHAT INDUSTRY OWES 
 
 known manufacturers are now producing guaranteed 
 analytical reagents of recognised standard degrees 
 of purity. 
 
 Drugs. After all the references we have made to 
 the work of the chemist in industry, we do not need 
 to labour the distinction between the man who 
 practises chemistry and the man who practises 
 pharmacy. The latter has to depend on the former 
 for many of the materials he employs in dispensing, 
 or the physician may prescribe with very uncertain 
 results, and the patient perish, or, in any case, pay to 
 no purpose. The subject of drugs and pharma- 
 ceuticals, with all its ramifications into the substances 
 compounded into medicines of all kinds, pills, powders, 
 ointments, lotions, tinctures, and so forth, is too 
 extensive for us to treat adequately, and we can only 
 deal with the subject by indicating a few develop- 
 ments in this important branch of industry. 
 
 Many of the drugs used in medicine are of vegetable 
 origin. Quinine, for instance discovered in 1820 by 
 Pelletier and Caventou is extracted from the bark 
 of trees of the Cinchona species. Strychnine is 
 obtained from the seeds of various plants such as 
 Strychnos mix vomica. Atropine is prepared from 
 deadly nightshade juice, which contains two alkaloids, 
 hyoscyamine and hyoscine. The juice is treated with 
 caustic potash, the hyoscyamine being thereby con- 
 verted into atropine. The mixture is shaken with 
 chloroform and the solvent evaporated, the atropine 
 being extracted with dilute sulphuric acid, precipi- 
 tated by potassium carbonate, and re-crystallised from 
 alcohol. A solution of the alkaloid has the property, 
 when placed in the eye, of dilating the pupil, a most 
 useful aid to the ophthalmic surgeon. 
 
 An increasing number of useful organic drugs, 
 including alkaloids, is now made synthetically from 
 other chemical substances. Many of these are 
 unknown in Nature, their production and utilisation 
 being solely due to science. Salicylic acid and its 
 derivatives, including aspirin, are made from phenol, 
 and used extensively in the treatment of rheumatic 
 and nervous disorders. On account of certain objec- 
 
TO CHEMICAL SCIENCE 89 
 
 tionable physiological properties, attempts have been, 
 and are being, made to obtain other derivatives that 
 have no such disadvantages, and good results have 
 been obtained with acetylsahcylic anhydride and 
 cinnamoylsalicylic anhydride. The antipyretics, 
 phenacetin and antifebrin, are made from phenol; 
 antipyrene, which is put to similar uses, being the 
 product obtained by methylating the pyrazolon 
 derivative formed by the condensation of acetoacetic 
 ester with phenylhydrazine. Derivatives of antipyrene 
 include salipyrene and tolypyrene. Veronal is 
 another synthetic drug. 
 
 The use of metallic compounds, as bactericidal 
 agents, has long been known. Compounds of mercury 
 have long been used in the treatment of certain dis- 
 eases. Recently the researches of Ehrlich on the 
 organic compounds of arsenic have done much to 
 alleviate suffering, such complex bodies being much 
 less poisonous to human beings than are the simpler 
 compounds of arsenic. Salvarsan and neosalvarsan 
 have met with success. One of the simplest of such 
 derivatives, atoxyl, has been used in the treatment of 
 sleeping sickness. 
 
 Local anaesthetics, administered hypodermically, 
 include cocaine, novacaine, and stoveine, the first 
 being extracted from the coca plant by alcohol acidi- 
 fied with a small quantity of sulphuric acid, and the 
 two latter being synthetic products. 
 
 Among antiseptics we must again mention phenol 
 (now being manufactured from benzene in large quan- 
 tities for making explosives), cresols, formaldehyde, 
 mercuric chloride corrosive sublimate and boric 
 acid ; while as disinfectants and insecticides, bleaching 
 powder, carbolic acid, potassium permanganate, 
 naphthalene, and zinc chloride all chemical products 
 are now largely used. 
 
90 WHAT INDUSTRY OWES 
 
 CHAPTER XIII. 
 PHOTOGRAPHY. 
 
 THIS beautiful and now almost essential art is 
 dependent upon the action of light on various 
 chemical compounds, principally the salts of silver. 
 It was first observed by Boyle about the middle of 
 the seventeenth century, that luna cornea silver 
 chloride darkens on exposure to light, and this 
 phenomenon was further investigated by the Swedish 
 chemist, Scheele, in 1784. No attempt, however, 
 was made to utilise this property for the production 
 of pictures until 1802, when Thomas Wedgwood 
 obtained prints of leaves and other flat bodies on 
 sensitive surfaces prepared by moistening white 
 leather or paper with silver nitrate solution. Similar 
 experiments were carried out by Sir Humphry Davy, 
 but the pictures produced lacked one important 
 advantage ; they were not permanent in daylight, and 
 therefore had to be kept in the dark and examined 
 only in weak, artificial light. The next workers of 
 note were Niepce and Daguerre, a great advance 
 being made by the latter, when, in 1839, he introduced 
 a new departure, well-known as the daguerrotyp 
 process. This was long ago superseded by other and 
 better methods, but it served the purpose of indicating 
 the right road to success. A plate of polished silver 
 was exposed to the action of iodine vapour, being 
 thereby covered with a film of silver iodide. On 
 exposure in a camera no apparent change took place 
 until development, as is the case with modern 
 photographic plates. The method of development 
 of the Daguerre plates was an accidental discovery. 
 Daguerre, while experimenting, was called away just 
 after he had removed a plate from his camera. For 
 safety, he put the plate in the first dark place that 
 
TO CHEMICAL SCIENCE 91 
 
 caught his eye a box containing odd pieces of 
 apparatus and when he returned to continue the 
 work, he was surprised to find that during his absence 
 the image on the plate had developed. Investiga- 
 tion of the contents of the box led to the final con- 
 clusion that the agent was some metallic mercury 
 loose in the bottom of the box. This provided the 
 means of development, the plates after exposure to 
 light being acted upon by the vapour of mercury. 
 The image was made permanent by dissolving the 
 unaltered silver iodide in the parts less affected by 
 light with a hot solution of common salt, an improve- 
 ment being almost immediately effected by the 
 suggestion of Herschel, that sodium thiosulphate 
 " hypo " was a more suitable fixing agent. 
 
 Meanwhile, other investigators had not been idle. 
 In the Calotype or Talbotype process, elaborated by 
 Fox Talbot, and introduced in 1841, we find the 
 principle of modern photography showing signs of 
 active germination. The method depended entirely 
 on the use of papers sensitised with chloride and 
 iodide of silver. In his earlier researches, a piece of 
 paper was covered with silver chloride by immersion, 
 successively in solutions of common salt and silver 
 nitrate. Prolonged exposure in the camera resulted 
 in the production of a negative image, which could be 
 fixed by common salt solution. This method wa 
 soon afterwards greatly modified in the following way. 
 The image formed by the camera lens was received 
 on a sheet of paper covered with silver iodide, and was 
 subsequently developed by a mixture of silver nitrate, 
 acetic acid, and gallie acid. When the resulting 
 negative was made transparent by means of wax, 
 positive prints could be obtained by allowing sunlight 
 to pass through the negative on to a piece of the sensi- 
 tive silver cKloride paper. The first use of glass 
 plates was made by Archer in 1851, the glass being 
 covered with a film of collodion in which cadmium 
 or zinc bromide or iodide had been dissolved. The 
 plate was sensitised by dipping into a solution of 
 silver nitrate and it was exposed in the wet state in the 
 camera, the image being developed by washing with 
 
92 WHAT INDUSTRY OWES 
 
 some reducing agent, such as ferrous sulphate. The 
 image being fixed by a solution of sodium thiosulphate 
 or potassium cyanide provided, when dried, a negative 
 from which any number of positive prints could be 
 taken. By this means the detail of the pictures was 
 better than that given by the older processes, and other 
 advantages were obtained, including the shortened 
 time of exposure of the more sensitive collodion film. 
 By this time very many workers had entered the 
 field, and the art made rapid strides. A further 
 improvement was the introduction of dry plates, the 
 sensitive surface being composed of gelatine impreg- 
 nated with silver bromide ; but to give a detailed 
 history of the development of modern photography 
 would be beyond the scope of this article. 
 
 The modern dry plates consist of sheets of glasa 
 cut to standard size and covered with a gelatine 
 emulsion of silver bromide. The emulsion is prepared 
 by the inter-action of ammoniacal silver nitrate with 
 excess of potassium bromide containing a little iodide 
 in hot gelatine solution, the emulsion, formed being 
 kept at a temperature of 45 deg. Cent, for some time 
 an operation which increases the sensitiveness. The 
 emulsion is then washed free from soluble salts, run 
 in an even coating on to the plates, and dried. After 
 exposure, the plates are developed by the reducing 
 action of certain compounds, such as pyrogallic acid, 
 hydroquinone, metol, ferrous oxalate, and others, with 
 various substances added to modify favourably the 
 course of development. The developed plates are 
 fixed by means of a solution of sodium thiosulphate, 
 well washed and dried. The introduction of celluloid 
 films has lessened the inconvenience attached to the 
 bulkiness and rigidity of plates, films being invariably 
 used when compactness and lightness of outfit are 
 required. 
 
 Many kinds of printing paper are available at 
 the present time. Silver chloride papers, both 
 in gelatine and collodion, are used for daylight 
 printing, ordinary P.O. P. being toned with a solution 
 containing gold chloride before fixing with hypo. 
 Self-toning papers require washing and fixing only, 
 
TO CHEMICAL SCIENCE 93 
 
 the paper already containing the necessary gold, but 
 modifications of tone may be obtained by washing 
 the prints in a solution of common salt before fixing. 
 Silver bromide and silver iodide are the sensitive 
 bodies in bromide and gaslight papers, of which many 
 varieties are on the market, these papers requiring 
 development, as in the case of plates. Beautiful 
 tones may be obtained by platinotype papers. 
 
 Other methods of printing include the carbon 
 process, depending upon the fact that when a gelatine 
 solution of potassium bichromate is exposed to light, 
 the gelatine becomes insoluble in water. Brilliant 
 black and white prints may be obtained by the 
 adhesion, after washing, of finely divided carbon to 
 the insoluble gelatine surface. The paper for the 
 blue prints familiar to engineers is prepared by immer- 
 sion in a solution containing potassium ferrocyanide 
 and ferrous ammonium citrate, the prints merely 
 requiring to be washed in water and dried. Other 
 methods have been devised to obtain engineers' 
 prints in various colours on a white ground, but for 
 most purposes the blue print method is adequate. 
 
 Colour photography, which has attracted much 
 attention during the last few years, has been developed 
 with some success. Many processes have been 
 devised, one of the most striking being the mirror 
 method of Lippmann, which depends upon the 
 interference of direct and reflected rays at different 
 depths in the film, the ultimate deposition of metallic 
 silver produced by development occurring at a distance 
 from the reflecting surface fixed by the wave length 
 of the impinging light. On viewing the developed 
 and fixed plate similar interference phenomena take 
 place with the consequent natural colouring of the 
 image. With the aid of orthochromatic and of pan- 
 chromatic plates, prepared by the use of various 
 dyes, combined with screens or colour filters, excellent 
 coloured photographs may be obtained. Three - 
 plate and single-plate processes are available, the 
 latter type being more convenient. The Lumiere 
 process is a single-plate process, in which the screen 
 consists of a mixture of starch grains, dyed red, 
 
WHAT INDUSTRY OWES 
 
 green, and blue, incorporated in a single layer in the 
 plate. All these colour photography processes, 
 however, are still somewhat expensive. 
 
 Mention could be made of many debts to photo- 
 graphy, including the discovery of radioactivity, 
 which was directly due to the sensitiveness of the 
 photographic plate, the discovery of stars too faint 
 to be observed by the most powerful telescopes, the 
 invention of photo -mechanical processes employed in 
 illustrating books and journals, photomicrography and 
 its numerous applications, and the cinematograph, 
 Apart from its everyday uses in peace and war. 
 
 Photographic Materials. The manufacture of 
 photographic materials is essentially a branch of the 
 fine chemical industry, since the production of good 
 results depends as much on the purity of the materials 
 employed as on the manner of employing them. 
 Developers, such as pyrogallic acid, metol, and hydro - 
 quinone, toning solutions containing gold chloride, 
 and the materials for making and sensitising plates, 
 films, and printing papers must necessarily be pure. 
 In fact, the whole art of photography depends, from 
 start to finish, on a high order of scientific work, both 
 chemical and physical. 
 
TO CHEMICAL SCIENCE 95 
 
 .CHAPTER XIV. 
 AGRICULTURE AND FOOD. 
 
 AGRICULTURE. 
 
 AGRICULTURE, though primarily concerned with the 
 cultivation of the soil tillage, pasturage, and 
 gardening may be regarded as the industry to 
 which we look, not only for food animal and 
 vegetable but, directly or indirectly, for clothing 
 and textiles, timber, drugs, leather, rubber, and a host 
 of other necessaries and comforts. Little reflection 
 is required to show that agriculture is dependent on 
 science, and, although many practical farmers 
 still scout such ideas, the various branches of the 
 industry owe much to geology, biology botany and 
 zoology chemistry, physics and meteorology, as well 
 as to the art of engineering. We propose to refer, 
 briefly, to the work of the chemist, especially in 
 connection with the subject of fertilisers. 
 
 The fear has been expressed from time to time that, 
 even making allowance for the effects of war, the pro- 
 duction of food will fall behind the needs of the 
 increasing population of the earth, unless science can 
 devise measures for coping with the problem. We 
 have shown how, through science, fields devoted to 
 the cultivation of indigo and madder have made way 
 for cereals, and we may confidently expect further 
 changes of the same kind, or even find, in the labora- 
 tory, means for obtaining food independently of the 
 processes of Nature by reproducing something akin 
 to the vital processes of vegetable and animal life. 
 
 Fertilisers. Mother Earth readily repays the kindly 
 attentions of man and offers an illimitable field to 
 science in the development of food supplies for man 
 and beast. The chemist examines the soil, decides 
 the means to be adopted for the restoration of its 
 
96 WHAT INDUSTRY OWES 
 
 fertility, and barren land is thereby reclaimed. 
 Natural manures, through the agency of which the 
 soil regains its creative energy, are supplemented by 
 artificial fertilisers, and the yield of foodstuffs is 
 increased. Thus, sodium nitrate, found in enormous 
 deposits in certain parts of Western South America, is 
 very largely used as a nitrogenous manure, the crude 
 material being purified by crystallisation. Potassium 
 sulphate, in the form of the mineral kierserite, 
 enriches the soil deficient in potash. Ammonium 
 sulphate, from the distillation of coal and shale, is 
 another valuable nitrogenous manure, and super- 
 phosphate of lime, prepared by the action of sulphuric 
 acid on mineral phosphates, provides a fertiliser 
 containing a large proportion of soluble phosphate. 
 The manufacture of this substance, moreover, has 
 been largely instrumental in keeping alive the lead 
 chamber process chamber acid, as such, being suit- 
 able for the purpose. 
 
 The calculation of Vergara that the South American 
 sodium nitrate beds would be exhausted by the 
 year 1923 has been proved to be erroneous. Surveys 
 of the known beds show that the supply from them 
 will be sufficient to meet the increasing demand for 
 the next fifty years or more, while the general character 
 of the country leads to the reasonable supposition 
 that other beds of vast extent exist and will be 
 capable of supplying the needs of the world for a 
 further 200 years. However, the end must come 
 sooner or later, and in view of the importance of this 
 substance, both as a fertiliser and as a starting 
 material in the manufacture of potassium nitrate, 
 nitric acid, and other nitrogen compounds, the 
 prospective shortage has given an impetus to research 
 with the object of utilising the nitrogen in the air. 
 One of the methods employed aims at the preparation 
 of nitrates by heating air in a specially constructed 
 electric furnace in which, by a suitable arrangement 
 of electro -magnets, the arc is caused to assume a 
 discous shape. The oxide of nitrogen produced is 
 led away to an oxidising chamber, where it is converted 
 by atmospheric oxygen into a higher oxide, which is 
 
TO CHEMICAL SCIENCE 97 
 
 absorbed by bases such as lime, soda, potash, or 
 ammonia. The process, primarily discovered by Sir 
 William Crookes, was adapted by McDougall and 
 Howies, in America, and later by Birkeland and Eyde, 
 in Norway, where electric power is cheap, and bases, 
 manufactured in Germany, were sent to Norway and 
 returned as nitrates. 
 
 The cyanamide process, which forms a great 
 German industry, consists in heating calcium carbide 
 with nitrogen in the electric furnace. The nitrogen 
 is obtained from liquid air by boiling off the oxygen, 
 or as residue from water gas or producer gas, which 
 has been used in the manufacture of hydrogen. The 
 cyanamide is applied directly as a manure, and on 
 exposure to water at ordinary temperature slowly 
 evolves ammonia, which, under the action of nitrifying 
 bacteria, is converted into compounds of nitrogen 
 readily absorbed by the plant. It may be noted also 
 that ammonia is easily formed by heating calcium 
 cyanamide with water under pressure. If barium 
 carbide is used instead of the calcium compound, the 
 main yield is barium cyanide, a convenient starting 
 material for the manufacture of other cyanides. 
 
 Nitrides, such as those of magnesium, boron, and 
 silicon, are prepared in the electric furnace, and find 
 application as manures rich in nitrogen and as sources 
 of ammonia, though their cost of production is rather 
 high. Many other processes have been patented and 
 used for the fixation of nitrogen, and British chemists 
 have not been idle, in spite of the difficulty of com- 
 peting against the lower cost of power in other 
 countries. Water power, abundant in Norway, is 
 readily converted into electricity, and is, therefore, 
 a most valuable possession in this connection ; but 
 we are assured that an earnest endeavour is being 
 made to produce nitrates in this country at the present 
 time. Incidentally, we would remark that the 
 fixation of nitrogen is of such importance that it is 
 practically certain that if Germany had not solved 
 the problem before the war, she could not have 
 maintained for so long the supply of munitions to her 
 army. 
 
98 WHAT INDUSTRY OWES 
 
 Basic slag the phosphatic slag from the Thomas 
 and Gilchrist basic Bessemer process when finely 
 ground is a useful manure for certain purposes, grass 
 land especially deriving benefit from its application. 
 Its employment in other directions has not, so far, 
 been extensive, possibly owing to the existence of a 
 somewhat arbitrary standard of valuation. It is 
 desirable that careful experiment should be made 
 with various crops to ascertain if this standard is 
 reasonable for all purposes. In the result it is not 
 unlikely that great dumps of slag, hitherto regarded 
 as waste, both from the basic Bessemer and from the 
 open-hearth processes, may be available for agri- 
 cultural purposes. 
 
 The quality of artificial fertilisers is to some extent 
 safeguarded by the provisions of the Fertilisers and 
 Feeding Stuffs Act, under which the seller of any 
 artificially prepared or imported fertiliser, and any 
 artificially prepared feeding stuff, is required to give a 
 warranty to the purchaser as to the constituents of 
 value in these articles, and an undertaking that the per- 
 centages found in these articles do not differ from those 
 stated in the invoice, beyond certa.in prescribed limits 
 of error. Official agricultural analysts and samplers 
 are appointed to assist in the administration of the 
 Act, and the Board of Agriculture is empowered to 
 make regulations for the purpose of carrying the Act 
 into execution. It is generally agreed, however, that, 
 with few exceptions, the county and borough authori- 
 ties concerned have practically ignored it, and beyond 
 appointing officials as required by the Act have given 
 them little or nothing to do, so that offending traders 
 are rarely brought to justice. 
 
 Feeding Stuffs. Among the principal artificially 
 prepared feeding stuffs for cattle and sheep may be 
 mentioned cotton cake and meal, which are very rich 
 in albuminoids, as are also cake and meal from the 
 ground nut and Chinese soya bean, and linseed and rape 
 cake, prepared from the marc or refuse from crushing 
 for oil. Other industries provide food material, such 
 as brewers' grains, malt dust and yeast, and beet 
 sugar fibrous wastes. 
 
TO CHEMICAL SCIENCE 99 
 
 FOOD. 
 
 While, as we have indicated above, the measures 
 taken to assure the quality of food for cattle are, to 
 a large extent, ineffective, those taken in respect of 
 our own food are certainly more satisfactory, although 
 the Sale of Food and Drugs Acts might, with advan- 
 tage, be more thoroughly administered in some parts 
 of the country. The term " food " includes every 
 article used for food or drink by man, other than 
 drugs or water, and any article which ordinarily 
 enters into, or is used in, the composition or prepara- 
 tion of human food, and also flavouring matters and 
 condiments ; the term " drug " includes medicines 
 for internal or external use. Public analysts are 
 appointed to examine samples chiefly milk and 
 dairy products taken under the Act, and proceedings 
 frequently follow both in the interests of health and of 
 the prevention of fraud. Some may protest that the 
 work of the public analyst is not in the interests of 
 industry, but it must be admitted that the honest 
 vendor is directly protected by the prosecution of the 
 fraudulent, and it should be noted also that many 
 prepared foods, such as biscuits, cocoa, margarine, 
 preserved meat, fish, fruits and vegetables, jams and 
 confectionery, and beverages are produced under 
 scientific supervision. 
 
 The methods of preservation of perishable food 
 products are due to the application of science. The 
 sterilisation by boiling of meat and of fish, followed 
 by immediate hermetic sealing in cans, is the result 
 of a knowledge of the nature of bacterial life, as also 
 is the practice of preserving by the application of 
 cold, the meat or fish being either actually frozen, or 
 maintained at a temperature near the freezing point 
 without actual congelation. We will refer again to 
 the subject of cold storage later. 
 
 The law governing the sale of milk in this 
 country enacts that the content of fat (cream) 
 shall be not less than 3 per cent. The various 
 preservatives available for use are either prohi- 
 bited, or are restricted as to the quantity that 
 
 H 
 
100 WHAT INDUSTRY OWES 
 
 may be added. This is a necessary precaution, as 
 most of the preservatives, such as formalin and boric 
 acid, are not desirable from the point of view of 
 health, especially in the case of milk, which is so 
 important to infants and invalids. The sterilisation 
 of milk by pasteurisation, which consists in prolonged 
 heating at a moderate temperature, is a useful means 
 of safeguarding the public health, the taste, and 
 therefore the palatability, of the milk being very little 
 affected by the treatment. 
 
 Science provides the means of distinguishing 
 between genuine butter and the various substitutes 
 now in common use, such distinction being necessary 
 for the detection of fraud. 
 
 Careful investigation by botanical workers, com- 
 bined with the proper application of manures, has 
 greatly increased the yield of cereals, and the cultiva- 
 tion of many other foodstuffs, such as roots, fruits, 
 tea and coffee, comes more and more under scientific 
 control, with beneficial results. We propose now to 
 consider, as an example, an important foodstuff, in 
 the production of which chemical, botanical and 
 mechanical sciences have played no mean part. 
 
 SUGAR. 
 
 Sugar is contained in the sap of many trees, such as 
 the date, palm, and the maple, and in nearly all fruits. 
 The main sources, however, are the sugar-cane and the 
 beet. The extraction of sugar from cane is said to 
 have been practised in Bengal and in China about 
 800 B.C., and existing records indicate that the Egyp- 
 tians, Arabs, and Persians were acquainted with cane 
 sugar over 1100 years ago. The cane is now culti- 
 vated in the West and East Indies, in the Southern 
 States,'and in South America. 
 
 In the old method of manipulation the cane, which 
 contains up to 18 per cent, of its weight in sugar, was 
 crushed between rollers, the expressed juice treated 
 with milk of lime to neutralise acidity, filtered and 
 evaporated to obtain the crystals. The solid was 
 separated by drainage in perforated casks, and the 
 mother liquor which contains various substances 
 
TO CHEMICAL /^eiESSf 
 
 which prevent complete crystallisation appeared on 
 the market as treacle or molasses, or was fermented to 
 make rum. With modern mechanical and chemical 
 developments the industry has been brought to a 
 state of great efficiency. The introduction of evapo- 
 rating pans and similar plant has effected marked 
 ecofcomy in fuel ; the crystals are separated by 
 centrifuges, resulting in great saving of time, and a 
 leaf has been taken from the book of the beet sugar 
 manufacturers by the employment of a diffusion 
 process to replace the crushing. The cane is shredded 
 and soaked in water, the sugar diffusing through the 
 cell walls of the cane into the water, and the yield 
 is enormously increased. 
 
 The process of refining crude sugar generally 
 consists in dissolving it in hot water blood being 
 added to very crude sugars to carry down impurities 
 in coagulating filtering, decolourising by the action 
 of animal charcoal, and evaporating to crystallisation. 
 The products are separated into various grades 
 according to purity. As an instance of the value 
 of scientific control in sugar-refining processes, we 
 may mention that one concern has for many years 
 past effected a saving of between 75,000 and 100,000 
 a year as a return for an expenditure of 20,000 a 
 yea,r on it laboratories and staffs of chemists. 
 
 Sugar was discovered in beetroot by Marggraf, a 
 German chemist, in 1747, but it was not until 1801 
 that a factory was established for its extraction, 
 the first being erected in Silesia by Achard. In 
 the light of present-day events it is interesting to 
 observe that the German industry received consider- 
 able impetus in its early years through the land 
 blockade of Prussia, enforced by Buonaparte, which 
 made the home production of sugar a necessity. 
 Buonaparte also gave encouragement to the estab- 
 lishment of the industry in France, and it is now 
 carried on in Russia, Holland, and other European 
 countries. The juice of the common beet contains 
 only a low percentage of sugar, but by careful 
 scientific cultivation the yield has been steadily 
 increased, so that some varieties give over 15 Ib. 
 
 H 2 
 
102 WHAT INDUSTRY OWES 
 
 of sugar per 100 Ib. of beet, instead of about 6 Ib. or 
 less. The yield of beetroot from the land has been 
 increased by about 15 per cent., and the coal con- 
 sumption in the process of extraction has been 
 reduced by about 80 per cent. The exhausted sub- 
 stance is utilised for making feeding stuffs for cattle. 
 In the early method of extraction the roots were 
 cleaned and shredded, the shreds placed in woollen 
 bags, and the juice squeezed out by hydraulic 
 pressure. This practice still prevails in some places, 
 but has been replaced in others by the cleaner and 
 more efficient diffusion process. The roots are 
 cut into thin strips which are exposed to the action 
 of water ; the sugar diffuses out into the water, 
 leaving colloidal substances in the cells, the walls 
 of which are impervious to colloids. The treatment 
 of the juice is similar to that employed in the case 
 of cane sugar, the yield of crystallised sugar being 
 about 70 per cent, of the sugar in the root, the other 
 30 per cent, remaining in solution as molasses or 
 treacle, to be sold as such or used to make rum. 
 
 Increased yields of sugar in the crystallised state, 
 from both cane and beet, are largely attributable 
 to the Osmose process, based on Graham's work 
 on dialysis, and the Elution processes elaborated by 
 Steffen and by Scheibler. In the first process the 
 sugar is allowed to diffuse through a parchment 
 membrane into pure water, the substances which 
 prevent crystallisation being unable to pass through 
 the membrane. The solution obtained is then worked 
 up for sugar and for potassium nitrate which accom- 
 panies it, while the remaining liquor goes to the 
 distillery for the manufacture of by-products. 
 
 The Elution processes depend on the formation of 
 the sparingly soluble calcium or strontium salts 
 formed by sugar calcium and strontium saccharates. 
 These salts, obtained by various methods in pure 
 condition from the sugar in molasses, are suspended 
 in water and decomposed into sugar and calcium or 
 strontium carbonate, as the case may be, by the action 
 of carbonic acid gas. 
 
 Other such processes have boen devised, but that 
 
TO CHEMICAL SCIENCE 103 
 
 involving the use of strontium hydroxide is most 
 largely employed. 
 
 COLD STORAGE. 
 
 A valuable by-product of the beet sugar industry 
 is trimethylamine, which is obtained by distillation 
 from the final residue or vinasses of the Osmose 
 process, and also in large quantities from herring-brine 
 by distillation with lime. It is a gas at ordinary 
 temperatures condensing in the cold to a liquid 
 which boils at 3.5 deg. Cent., and is used, as we have 
 noticed before, in the place of ammonia, in the 
 manufacture of potassium bicarbonate by a method 
 analogous to the ammonia soda process. By heating 
 its hydrochloride with hydrochloric acid, methyl 
 chloride, an easily condensable gas, is obtained, and 
 used for making certain dyes, and also as a freezing 
 agent in the technical production of ice. 
 
 The preservation of food by cold storage is of 
 great importance, and depends for its usefulness 
 upon the availability of a large and cheap supply of 
 ice. In the preparation of ice, advantage is taken 
 of the heat absorption of boiling liquids. A gas 
 that can easily be liquefied by pressure can be used 
 as a freezing agent, provided that its other properties 
 are not objectionable. The gas is liquefied by 
 mechanical pressure, and is then allowed to evaporate 
 under low pressure, the only heat available for its 
 vaporisation being that contained by the water it 
 is desired to freeze. The freezing agent is, of course, 
 not destroyed, but can be recondensed and used 
 over again. Gases in common use as freezing agents 
 are methyl chloride, which liquefies t at ordinary 
 temperature under two or three atmospheres pressure, 
 and boils under ordinary pressure at 24 Centigrade 
 degrees below zero, ammonia gas, which liquefies 
 under about six or seven atmospheres and boils under 
 ordinary pressure at 33.5 Centigrade degrees below zero, 
 carbonic acid gas, and cymogene (referred to in 
 Chapter V.). 
 
104 WHAT INDUSTRY OWES 
 
 CHAPTER XV. 
 BREWING. 
 
 THE production of malted liquors was one of the 
 first industries to recognise the value of scientific 
 investigation in the elucidation of technological pro- 
 blems ; but the industry has not alone profited the 
 field of work has proved so rich in discovery that an 
 important domain of chemical science, the chemistry 
 of fermentation, with its applications to the leather, 
 tobacco, food and other industries, as well as to physio- 
 logical science, has been opened up, primarily through 
 the study of the principles underlying the practice 
 of brewing. 
 
 Alcoholic liquors were brewed from grain stuffs in 
 Egypt as early as the 4th Dynasty (B.C. 3000 to 
 4000), the beverages taking the place of wine in 
 countries where the climatic conditions were un- 
 favourable to the cultivation of the vine. Although 
 the Egyptians had vineyards in the Nile Valley, it is 
 probable that this restriction of area gave rise to the 
 brewing of grain liquors in other less favoured parts. 
 The earliest fermented liquor known in Britain was 
 mead, made from honey ; the production of beer 
 from barley, and of cider from apples followed in the 
 order indicated. All three beverages were in use in 
 the South of England at the time of the invasion by 
 the Romans, who are said to have considerably 
 improved the manufacture of beer, which subse- 
 quently became the national drink of the country. 
 In the Middle Ages rents were sometimes paid in malt 
 or beer, and it is not without interest to note that one 
 of the municipal appointments in the time of Queen 
 Elizabeth was that of the ale -taster, a post held 
 by the father of William Shakespeare at Stratford- 
 on-Avon. Ale-tasters were required to examine 
 
TO CHEMICAL SCIENCE 105 
 
 beer and ale to see that they were good and whole- 
 some, and sold at proper prices. Public analysts 
 may now be considered to carry on these duties, 
 the custom of appointing ale -tasters having been 
 discontinued in most places since beer and ale 
 became excisable commodities. 
 
 In normal times about 35 million barrels of 36 gallons 
 are brewed per year in the United Kingdom, involving 
 the consumption of 50 million bushels of malt, over 
 60 million pounds weight of hops, more than a million 
 hundredweights of specially prepared rice and 
 maize, and about three million hundredweights of 
 sugar. 
 
 The question of water supply is of great importance 
 to the brewer, the nature of the impurities in the 
 water used in mashing greatly influencing the quality 
 of the product. The excellence of the pale ales pro- 
 duced at Burton has been traced to the existence in 
 solution of large quantities of calcium and magnesium 
 sulphates in the Burton well water. Stout and porter 
 are better brewed with the softer water of London or 
 Dublin, which does not contain the sulphates above 
 mentioned. Sometimes the water in a locality can be 
 so modified, by the addition of the requisite substances, 
 as to be suitable for the brewing of different classes 
 of beer ; but the industry has been largely established 
 in districts where the natural supply needs no special 
 treatment. 
 
 The production of beer from barley involves three 
 main operations : the conversion of the grain into 
 malt ; the preparation of an infusion of the malt 
 called wort ; and the fermentation of the wort by 
 means of yeast. Malt is obtained by keeping barley 
 in a moist atmosphere until the induced germination 
 has proceeded to the requisite extent determined by 
 examination of the grain. The product is then 
 heated to a temperature above 50 deg. Cent, to stop 
 germination. The infusion known as wort is made by 
 mashing the finely ground malt with water, and 
 keeping it for some time at about 67 deg. Cent. The 
 resulting liquor, after straining through spent wort, 
 is sterilised by boiling, when hops are added to impart 
 
106 WHAT INDUSTRY OWES 
 
 a bitter flavour, and to yield to the liquor certain 
 preservative substances. The liquor is then cleared 
 by settling, drawn off, cooled by " coolers " and 
 refrigerators, and fermented by yeast. 
 
 The chief change taking place in malting barley is 
 the production of an active body called diastase, which 
 has the power to convert starch into sugar. During 
 malting albuminoid substances are broken down into 
 simpler bodies, and the starch undergoes modifica- 
 tions, assuming a form more easily attacked by the 
 diastase. During the mashing operation the starch 
 is converted by the diastase into a sugar, which is fer- 
 mentable by yeast, thereby yielding alcohol. As the 
 finished malt contains much more diastase than is 
 necessary to convert all the starch present into sugar, 
 starch, in the form of flaked rice or flaked maize, is 
 sometimes added to the malt before mashing, the 
 final result being an increased production of alcohol. 
 When desirable the quantity of sugar in the wort can 
 be increased by. the direct addition of invert sugar 
 or of glucose. Invert sugar, which contains nearly 
 equal quantities of two fermentable sugars dextrose 
 and laevulose is produced in large quantities for the 
 use of brewers b^ boiling cane sugar with dilute 
 mineral acids, whilst glucose, containing two sugars 
 dextrose and maltose is made by the hydrolytic 
 action of dilute mineral acids on starch, an inter- 
 mediate product being dextrin (British gum). If 
 the action of the acid were further prolonged dextrose 
 alone would be the main product. Brewers' 
 glucose contains 6070 per cent, of fermentable 
 sugars. 
 
 By boiling, the wort is sterilised and concentrated, 
 certain complex protein bodies are eliminated by 
 precipitation, diastatic action is stopped, and the 
 flavouring and preservative materials are extracted 
 from the hops which are added at this stage. Hops 
 contain a yellow granular powder called lupulin, 
 which is the most valuable constituent from the 
 brewers' point of view. The lupulin in new hops may 
 amount to 15 per cent, or more, and contains resins 
 and bitter principles, which give a flavouring and 
 
TO CHEMICAL ^SCIENCE 107 
 
 exert a preservative action on the beer ; and 
 certain volatile essential oils which also improve the 
 flavour. 
 
 By fermentation with yeast the sugars in the wort 
 are transformed into alcohol and carbonic acid gas. 
 The growth of yeast, when supplied with suitable 
 foods, and its remarkable action on certain sugars, 
 have held the attention of scientific men for years. 
 Liebig, in 1839, advanced the theory that yeast, an 
 unstable nitrogenous compound, possessed the pro- 
 perty of communicating this instability to sugars, 
 causing them to decompose, but the living nature of 
 yeast was not then recognised. About thirty years 
 later Liebig' s views were overthrown by Pasteur after 
 a long controversy, and Liebig was compelled to make 
 certain modifications in his theory. As the result of 
 a series of epoch-making experiments, Pasteur came 
 to the conclusion that yeast was an organism capable, 
 under certain conditions, of maintaining its life with- 
 out the aid of atmospheric oxygen, that element being 
 derived from sugars, the presence of which fulfilled 
 the conditions. The maximum fermentative power 
 of yeast was therefore attained in the absence of 
 atmospheric oxygen. This theory held the field until 
 1892, when the researches of Adrian J. Brown showed 
 it to be untenable. In 1897 Buchner demonstrated 
 that the living yeast cell is not necessary for fermen- 
 tation, but that the clear liquid extracted from the 
 yeast by heavy pressure served the purpose. He 
 proved conclusively that the cause of the fermentation 
 is an enzyme, which he called zymase. Further light 
 has been thrown on the problem by Arthur Harden, 
 who separated the active liquid into two inactive 
 constituents the enzyme and the co -enzyme which, 
 when remixed, became once more active. Harden 
 has also shown the importance of phosphates in 
 accelerating the change. To summarise: the living 
 yeast contains and reproduces an active non-living 
 body which is capable of converting sugars into 
 alcohol and carbonic acid gas. The yeast grows 
 at the expense of certain foods present in the 
 wort. 
 
108 WHAT INDUSTRY OWES 
 
 Utilisation of Waste Products. Dried yeast is used 
 as a cattle food, and as the source of an excellent 
 substitute for meat extract. Carbonic acid gas is 
 compressed and used for the aeration of beer and 
 mineral waters. 
 
TO CHEMICAL SCIENCE 109 
 
 CHAPTEB XVI. 
 ALCOHOL, WINES AND SPIRITS. 
 
 ALCOHOL is one of the most important chemical 
 products. We have already referred to it as a 
 solvent, in which capacity it is of great service to the 
 chemist in the laboratory as well as in industrial 
 operations involved in the manufacture of transparent 
 soap, varnishes, French polish, collodion, and celluloid. 
 It is not only as a solvent, however, that it figures 
 extensively in the arts and manufactures. It is used 
 in the technical preparation of chloroform, iodoform, 
 fulminates, ether, acetic acid, and many other bodies. 
 For certain purposes such as the production of some 
 kinds of whiskey and brandy, and of liqueurs, and in 
 the manufacture of scents, fine chemicals and drugs 
 only alcohol of a considerable degree of purity can 
 be used, and the expense is correspondingly high. 
 
 Alcohol is made from the cheapest starchy materials 
 available, such as potatoes, maize, turnips, molasses. 
 The raw material is mashed with about 5 per cent, 
 of malt, and fermented in the usual way. After 
 distillation in a Coffey still, the spirit is diluted with 
 water, filtered through wood charcoal to remove 
 fusel oil and redistilled through a fractionating 
 column. The products are separated into three 
 grades : first runnings, and first and second quality 
 spirits. The first runnings, containing about 95 per 
 cent, of alcohol with a small quantity of aldehyde, 
 may be used for burning and in manufactures where 
 the impurities give rise to no deleterious effects. 
 The first and second qualities, which are 96 to 97 per 
 cent, in strength and contain only traces of aldehyde 
 the second quality also containing a small quantity 
 of fusel oil are known as silent spirit, because they 
 afford no evidence of their source. These qualities 
 
110 WHAT INDUSTRY OWES 
 
 are used for drinking purposes liqueurs and factitious 
 brandy and whiskey and for pharmaceutical pre- 
 parations. 
 
 Absolute alcohol, containing 99 per cent, or more of 
 alcohol, is obtained by dehydrating the finer spirits 
 by redistilling with about half their weight of quick- 
 lime, whilst 100 per cent, alcohol may be prepared by 
 the addition of a small quantity of metallic sodium 
 to absolute alcohol and further redistillation. 
 
 The denaturing of industrial spirit rectified spirit 
 and first runnings consists in adding to the alcohol, 
 to render it undrinkable, some substance or substances 
 which cannot be profitably separated, and which have 
 the minimum harmful effect in the | processes 
 demanding the use of such spirit. Were it not for 
 the fact that in most countries the Governments per- 
 mit the sale and use of denatured or undrinkable spirit 
 free of duty, the high duty on such spirit would 
 render its use in ordinary manufactures prohibitive 
 from the point of view of economy, and the absence 
 of such facilities would prove a great hindrance to 
 the industries concerned. 
 
 Methylated spirit is duty free, and may be used 
 instead of rectified spirit spirits of wine in the 
 manufacture of chloroform and varnishes, for pre- 
 serving anatomical specimens and for many other 
 purposes. It was originally made by adding about 
 10 per cent, of methyl alcohol wood spirit a product 
 of the destructive distillation of wood, which has a 
 sharp fiery flavour and contains substances dis- 
 agreeable both to taste and smell. The presence of 
 wood spirit, however, has little or no effect on the 
 industrial uses of alcohol, from which, moreover, it 
 cannot be profitably removed. The main use of 
 wood spirit, therefore, is for denaturing purposes ; 
 but it is also employed as a solvent for resins and in 
 the manufacture of dyes, its characteristic component 
 CH S , appearing in this role as a constituent of the 
 intermediate products methylaniline and dimethyl - 
 aniline, bases largely used for the production of basic 
 dyes, such as methyl violet the colouring matter of 
 recording, copying, and typewriting inks malachite 
 
TO CHEMICAL SCIENCE 111 
 
 green, and methylene blue. The processes for the 
 extraction and purification of wood spirit, however, 
 were in the course of time so far improved, that its 
 purity eventually unfitted it for use alone as a de- 
 naturant ; it is still universally used for the purpose, 
 but with the enforced addition of other more dis- 
 agreeable substances, such as in the case of ordinary 
 methylated spirit not less than f per cent, of 
 paraffin of specific gravity 0.800. For some manu- 
 facturing purposes the paraffin is a disturbing factor, 
 causing turbidity on mixing with water, and being 
 unsatisfactory in other respects. To obviate these 
 disadvantages, various denatured spirits are now 
 made, containing from 2 to 10 per cent, of wood 
 spirit with a smaller quantity of other substances of 
 unpleasant taste, the choice being determined 
 according to the purpose for which the spirit is to be 
 employed. Thus, in the manufacture of transparent 
 soap, a spirit denatured with wood spirit, castor oil 
 and caustic soda is useful ; in making mercury 
 fulminate, a mixture of wood spirit with pyridine 
 bases forms a suitable denaturant ; and in making 
 celluloid the spirit may be mixed with wood spirit, 
 camphor, and benzene. Other denaturants include 
 toluol, xylol, wood vinegar, turpentine, animal oil, 
 chloroform, iodoform, and ethyl bromide, according 
 to the needs of the industry for which the spirit is 
 required. 
 
 Wines. The production of wines by the fermen- 
 tation of grapes is an industry of great antiquity. 
 Several words in Hebrew are translated in our Old 
 Testament as wine, and we find it associated with Noah, 
 who, when he began to be an husbandman, planted 
 a vineyard, drank of the wine and was drunken. 
 Fermented grape juice was a beverage of the ancient 
 Egyptians five or six thousand years before our time. 
 
 Wine is made by allowing the juice of grapes 
 to ferment spontaneously, the organism inducing 
 the change occurring plentifully in the air dust of 
 vine-growing countries, and speedily infecting any 
 sugary liquor freely exposed to the air. When white 
 wine is the product desired, all the seeds and husks 
 
112 WHAT INDUSTRY OWES 
 
 of the grapes are carefully excluded, because it is 
 from these that the colouring matter of red wines 
 is extracted by the alcoholic liquid produced by 
 fermentation. The seeds and husks also give up 
 a small quantity of tannin, which acts favourably 
 as a preservative of the red wines, and prevents 
 ropiness. Sparkling wines, such as champagne, are 
 made by dissolving sugar in a still wine and allowing 
 it to undergo secondary fermentation in the bottle. 
 Ordinarily, wine consists of a mixture of alcohol 
 and water, containing from 7 to 17 per cent, of the 
 former, together with smaller quantities of sugar, 
 bitartrate of potash, glycerine, and other bodies, 
 including traces of flavouring matters. If a sugar 
 solution contains much more than 30 per cent, of its 
 weight of sugar it cannot be fermented by yeast. 
 A solution of alcohol of 16-17 per cent, strength 
 also inhibits the action of yeast, and it follows, 
 therefore, that fermented liquor cannot contain more 
 than this percentage. Should a wine of greater 
 strength be desired, it can be obtained only by the 
 addition of stronger distilled spirit. Thus the 
 strongest port wine, as produced by the ordinary 
 fermentation, contains not more than 16 to 17 per 
 cent, of alcohol, but it can be " fortified " if necessary 
 by the addition of absolute alcohol or rectified spirit 
 in the proper proportion. For this purpose it is 
 desirable to use the strongest alcohol obtainable, 
 as if a weaker, e.g., less than 90 per cent., were used, 
 the water necessarily added with it would dilute 
 the other ingredients of the wine to an abnormal 
 extent, and modify unfavourably its original 
 characteristics. 
 
 Spirits may be divided roughly into two classes, ( 1 ) 
 pot-still spirits, including brandy and whiskey ; and (2) 
 gin spirits, made by the suitable treatment of plain 
 rectified spirit or alcohol. The manufacture of 
 spirits was made possible only by the discovery 
 of the process of distillation, and is not, therefore, 
 of such antiquity as the wine and beer industries. 
 The products differ from fermented liquors from which 
 they are produced, mainly in the larger content of 
 
TO CHEMICAL SCIENCE 113 
 
 alcohol, in the absence of non-volatile matter, and 
 in the possession of certain distinct flavouring matters, 
 either occurring naturally or added purposely. 
 Cognac brandy is made by distilling from a pot 
 the fermented juice of a small variety of grape, 
 the alcohol passing over among the first products 
 of the distillation. The spirit contains about 50 per 
 cent, of alcohol, and owes its aroma and flavour 
 to small quantities of capric (cenanthic) ester derived 
 from the wine. The colour of genuine old brandy 
 is due to colouring matter extracted from the wood 
 of the casks in which it is stored, its astringent 
 flavour being due to tannin from the same source. 
 New brandy is coloured to resemble the old by the 
 addition of caramel (sugar generally starch sugar 
 heated to about 190 deg. Cent.), astringency being 
 sometimes imparted by an infusion of tea. 
 
 Whiskey is made from malted barley, or from 
 a mixture of unmalted and malted grain, the mixture 
 being dried over a peat fire, from which the whiskey 
 derives its smoky flavour. By a washing operation 
 similar to that practised by brewers, a wort is produced 
 which is cooled quickly by refrigerators and fermented 
 by purified brewers' yeast, as completely as possible, 
 at a low temperature. These conditions combine 
 to ensure the production of a good liquor free from 
 sourness, and with the minimum of wasteful and 
 objectionable impurities such as fusel oil and 
 aldehyde. When the fermentation stops, the liquor 
 is distilled from a large copper still up to 12,000 
 gallons sometimes with the addition of soap to 
 prevent undue frothing until all the alcohol has 
 passed over. The distillate from this operation 
 known as " low wines " is poor in alcohol and requires 
 a second distillation. The residue remaining in 
 the still contains a small quantity of lactic acid, 
 which is often recovered and used as a substitute 
 for acetic and tartaric acids in processes where a 
 weak acid is required, and where the chemical nature 
 of the acid is not of first importance. The second 
 distillate is collected in three fractions called " fore- 
 shoots," " clean spirits," and " feints." The clean 
 
114 WHAT INDUSTRY OWES 
 
 spirit is a strong whiskey containing about 60 per 
 cent, of alcohol. It is generally diluted with water 
 to about 40 per cent, before being sold to the customer, 
 the minimum being fixed by Act of Parliament (1879) 
 at 37 per cent, by weight. The fore-shoots are 
 highly impure, containing fatty acids and other 
 substances, while the " feints " consist chiefly of 
 fusel oil, a mixture of higher boiling alcohols, used 
 in recent years as a raw material in the production 
 of synthetic rubber, and also as a solvent. The 
 " spent lees " remaining in the still is a waste for 
 which as yet no useful application has been found. 
 
 British brandy and whiskey prepared in a similar 
 way from potato starch need to be freed from a rather 
 larger percentage of fusel oil than does barley spirit. 
 
 Rum, which is made by fermenting treacle or 
 molasses, and twice distilling the product, owes its 
 flavour to formic and butyric esters, and is coloured 
 either by ageing in wood, or artificially by means of 
 caramel. 
 
 The plain spirit, i.e., a mixture containing water 
 and alcohol only, which is used to make gin and 
 liqueurs, is produced by fermenting a mixture of 
 malted and unmalted grain, and distilling the resulting 
 alcoholic liquor or " wash " through a special fraction- 
 ating apparatus such as the Coffey still. W T hen 
 distillation takes place from a pot-still little fraction - 
 ation occurs, and a large proportion of the lower 
 and higher boiling substances pass over with the 
 alcohol, necessitating a second distillation ; but by 
 the use of a contrivance such as the Coffey still, 
 which is too complicated for description here, the 
 greater proportion of the impurities can be eliminated 
 by one distillation. 
 
 Gin is made by adding some substance, such as 
 juniper or liquorice root, to the spirit, and re-dis- 
 tilling from a pot, when the distillate passing over 
 carries with it the flavouring matter extracted 
 from the root. Liqueurs are made by dissolving 
 large quantities of sugar in the alcohol with various 
 flavouring and colouring materials. 
 
TO CHEMICAL SCIENCE 115 
 
 CHAPTER XVII. 
 
 TOBACCO, INKS, PENCILS, &c. 
 
 TOBACCO is cultivated in many countries, especially 
 in Virginia and the Southern States, in Mexico, 
 Cuba, and the West Indies, in Asia Minor and Persia, 
 in India, China, and Borneo, and in South Africa, 
 and affords scope for the botanist, biologist, and 
 chemist, both in the plantations and in the factories. 
 In the days of Columbus the natives of the West 
 Indies smoked the rolled leaf, the Mexicans and 
 North American Indians used pipes, and the Aztecs 
 and Hispaniolan Indians applied forked tubes to 
 the nostrils. Tobacco was introduced into Europe 
 by Hermandez de Toledo in 1559, into England by 
 Sir John Hawkins in 1565, and its use speedily 
 became very general in spite of all forms of opposition. 
 Smoking was the butt of the wits, denounced by 
 the clergy, and condemned by rulers and popes, 
 offenders being subject to severe punishment. In 
 Turkey it was a capital offence, and in the canton 
 of Berne was prohibited as an addition to the deca- 
 logue. In England King James I. issued a " Counter - 
 blaste to Tobacco," in which smoking was described 
 as " a custom loathsome to the eye, hateful to the 
 nose, harmful to the brains, dangerous to the lungs" 
 . . . as " resembling the horrible smoke of the pit 
 that is bottomless ; " but although often the subject 
 of violent diatribes, it remains at the present day 
 a most popular luxury among, both rich and poor, 
 and we may contrast the views of the Stuart King 
 with those of Kingsley indicated in " Westward Ho ! " 
 " When all things were made none was made better 
 than Tobacco ; to be a lone man's Companion, a 
 bachelor's Friend, a hungry man's Food, a sad man's 
 
 r 
 
116 WHAT INDUSTRY OWES 
 
 Cordial, a wakeful man's Sleep, a chilly man's Fire. 
 There's no herb like it under the canopy of Heaven." 
 
 Tobacco is rarely prescribed in medicine or 
 employed in pharmacy ; but it is well known that 
 smoking in moderation acts as a sedative, and is often 
 beneficial in promoting expectoration in cases of 
 asthma. Snuff, which is prepared from the ribs 
 and stems of the tobacco leaf, is occasionally recom- 
 mended to excite the secretion of mucus from the 
 nasal membrane. The absorption of very small 
 quantities of nicotine is stimulating to mind and 
 body, but in excess the effect is depressing, narcotic, 
 and injurious to the sight. Much depends upon 
 the constitution of the smoker, habituation, and other 
 circumstances. But we have digressed from our 
 object. The industry is an important one from the 
 financial standpoint. In normal times we spend 
 between four and five million pounds on imported 
 tobacco more than twice the expenditure on dyes 
 and the smoker pays very heavily to the Exchequer for 
 his luxury. He is protected, however, by the 
 inspection of imported tobacco by the Government 
 laboratory. Many thousand samples are examined 
 annually, in accordance with the legislation for- 
 bidding adulteration or excess of moisture, offenders 
 being liable to heavy penalties. Tobacco was formerly 
 much adulterated with leaves of rhubarb, cabbage, 
 dock and the like, as well as with sugar, starch, 
 and gum ; but although sweetening matters such 
 as sugar, treacle, liquorice, and glycerine are occasion- 
 ally present in imported tobacco, adulterants are 
 now comparatively rarely detected. 
 
 The chemical composition of tobacco is highly 
 complex, the determinable constituents numbering 
 over twenty. The quality of the leaf is attributed 
 to the nature of the soil where it is grown, though the 
 finished product must remain largely a matter of taste. 
 The methods of manufacture depend on the variety 
 of tobacco and the purpose for which it is intended ; 
 and the processes are supervised more and more 
 by men of hcience who can render useful assistance 
 in many ways, such as the prevention of mouldiness 
 
TO CHEMICAL SCIENCE 117 
 
 and the utilisation of waste. The leaves, when 
 harvested, are allowed to wither to a certain extent, 
 and then undergo shed-drying or sweating in moderate 
 heaps covered with matting. The leaf cells transpire 
 carbohydrates, albuminoid matters become con- 
 verted into amides, and the heat generated effects 
 the drying of the leaves, which then undergo fermenta- 
 tion in bundles arranged in large heaps. Tons of 
 tobacco are thus allowed to decompose rapidly at 
 a temperature usually kept below 50 deg. Cent., 
 the bundles being turned about so that all are equally 
 affected. Suchsland is stated to have prepared 
 cultures of the bacteria of the fermentation, and to 
 have transferred them from fine West Indian to 
 German tobacco in the course of fermentation, 
 with remarkable improvement to the latter. 
 
 The leaf as imported to this country is subjected 
 to secondary fermentation after the addition of 
 5 to 25 per cent, of water, and is dried or stoved on 
 heated open trays, or in closed ovens subjected 
 sometimes to injections of steam, different methods 
 of treatment affecting the flavour of the product. 
 The content of nicotine in the leaf varies from 1 to 
 5, though it is sometimes as high as 8 per cent.; a 
 single cigar often contains a deadly dose, but it retreats 
 from the heat as the tobacco burns and accumulates 
 in the stump or butt. By passing a current of steam 
 through a mixture of lime and tobacco dust, neutralis- 
 ing the resulting liquid with sulphuric acid, and adding 
 caustic potash, nicotine is liberated and may be 
 dissolved in ether, the solution yielding almost 
 pure alkaloid, which is employed in the manufacture 
 of insecticides for horticultural purposes. 
 
 We propose now to deal with a few industries under 
 scientific control which employ chemical products, 
 and relate to commodities in everyday use. 
 
 Inks. In early times the thoughts and actions of 
 men were incised on stone, impressed on clay or wax, 
 or carved on ivory, metal or wood ; but with the 
 introduction of papyrus, which we have mentioned in 
 
 i 2 
 
118 WHAT INDUSTRY OWES 
 
 the chapter on cellulose, characters were formed by the 
 application of coloured fluids by means of a brush or 
 reed. The word " ink " is associated more closely 
 with the more ancient methods, being derived from 
 the Greek encaustos (burnt in), and from the Latin 
 encaustum (the purple-red ink used by the later 
 Roman Emperors). The oldest writing material 
 appears to have been composed of very finely divided 
 carbon hi a solution of an adhesive substance, which 
 held the carbon in suspension and fixed it to the 
 papyrus. Ink of this sort has been found on ancient 
 Egyptian papyri, and was no doubt also in use in 
 China at least as early. Carbon inks are permanent 
 and very resistant to chemical action, but there is a 
 tendency for the pigment to sink in the liquid unless 
 it is frequently stirred. Printing inks also consist 
 mainly of carbon with well-boiled drying oils and soap 
 or resinous matter. For ordinary writing purposes, 
 however, carbon inks were superseded centuries ago 
 by iron-tannin inks, prepared from a decoction of 
 galls with copperas and gum arabic, formerly home 
 made, but now produced in common with many other 
 domestic requirements on an industrial scale. The 
 action of the tannin from the decoction of galls on 
 the copperas produced a precipitate, which, being 
 insoluble, formed a deposit, but manufacturers 
 avoided these conditions by excluding air to prevent 
 oxidation, and by adding soluble colouring matter. 
 Good writing ink should remain sweet and fluid when 
 exposed to air, should be permanent to light under 
 ordinary atmospheric conditions, and not contain an 
 excess of free acid which would injure the pen and 
 paper, though the ink is not always to be blamed for 
 these contingencies. In the middle of the eighteenth 
 century logwood was added ; in many cases it replaced 
 the tannin entirely, and still forms the basis of some 
 inks. Coloured inks have also been prepared with 
 cochineal and indigo, and with the introduction of 
 coal tar dyes a large variety of easily running inks, 
 specially suitable for stylographic and fountain pens, 
 have been rendered available, though it should be 
 remarked that they are not regarded as so permanent 
 
TO CHEMICAL SCIENCE 119 
 
 as the iron-gallo-tannates. Many typewriter ribbons 
 are prepared with coal tar dyes, and are therefore open 
 to this objection, the ink being fairly easily removed by 
 chemical means. Inks highly sensitive to tampering 
 are employed for bankers' cheques, and the detection 
 of forgeries often depends on the effects produced by 
 treatment with various chemical reagents. Copying 
 inks are concentrated writing solutions, usually con- 
 taining two or three times the amount of colouring 
 and thickening matter. It is probably no news to 
 engineers that James Watt invented the copying 
 press, the patent for which was granted to him in 1780. 
 He employed an ink prepared from a decoction of 
 Aleppo galls, green copperas and gum arabic, which 
 is much the same as the inks now used for the same 
 purpose, except that they contain soluble dyes, 
 dextrin or sugar, and in some cases glycerine. Iron 
 tannin inks, when exposed to the air, become oxidised 
 and insoluble, so that they cannot be copied. 
 
 The juices of various plants have long been utilised 
 as marking inks, such plants including the ink plant 
 of New Granada and New Zealand, the cashew nut, the 
 Indian marking nut and others. Modern marking 
 inks, which should withstand the action of soap and 
 alkaline and acid liquids, mainly consist of solutions 
 of silver nitrate coloured with lampblack and thick- 
 ened with gum. Salts of gold, platinum, manganese, 
 and of other metals have been used for the same 
 purpose. 
 
 Pencils. We have already noted the use of the 
 brush for applying characters to papyrus. The word 
 " pencil " is derived from the Latin penicillus, a small 
 tail. The use of charcoal and similar materials followed 
 and, at an early date, metallic lead was employed to 
 mark parchment and papers ; hence, the term 
 " blacklead " as applied to pencils, denoted the 
 blacker mark of graphite or plumbago. As a matter 
 of fact, the graphite used for making pencils consists 
 almost entirely of carbon and contains no lead. 
 It has been employed for this purpose since the 
 seventeenth century, and for a long time was obtained 
 almost exclusively from the Borrowdale mines in 
 
120 WHAT INDUSTRY OWES 
 
 Cumberland, being mined in compact grey-black 
 masses, cut into thin plates, then into rectangular 
 sticks and cased in wood. The mine was guarded 
 by an armed force, and, to maintain the monopoly, 
 an Act was passed restricting the working to only 
 six weeks in the year ; for the remainder it was 
 flooded to prevent theft. The best quality was 
 exhausted early in the nineteenth century, and the 
 pencil manufacturers turned their attention to 
 utilising accumulations of waste from cuttings of 
 the original masses, which were crushed and mixed 
 with other materials. 
 
 One of the results of such experiments was the 
 introduction of varying degrees of hardness in which 
 respect the native graphite was never uniform. 
 Conte, of Paris, is credited with the method now 
 generally employed, of making pencils from finely 
 ground graphite mixed with varying proportions of 
 clay, allowing for fourteen degrees of hardness and 
 softness ranging from 6 H to 6 B with HB (hard 
 and black), and F (firm) as the middle degrees. 
 
 Graphite has since been found in many parts of 
 the world. The crystalline variety occurs in Ceylon, 
 but is not sufficiently black for pencil-making ; 
 the massive, which occurs in Bohemia, Bavaria, 
 and Mexico, is much blacker. It is ground very 
 fine, mixed with water, and passed through tanks 
 to allow the heavier particles to fall, the finer particles 
 passing on to five or six successive tanks, when the 
 necessary degree of fineness having been obtained, 
 it is mixed with suitable clay which has been washed 
 in the same manner. The mixture is submitted 
 to further grinding, squeezed in bags to remove 
 superfluous water and forced through tubes to 
 produce strips of the required shapes and sizes, which, 
 when dried and baked, are ready for casing in wood. 
 
 The wood mostly used for making pencils is that 
 of red cedar, not the cedar of Lebanon, but the 
 Juniperus Virginiana which grows in Florida, 
 Alabama, and Tennessee, and lends itself well to 
 the purpose on account of its soft character and 
 straightness of grain. It is usually cut into short thin 
 
TO CHEMICAL SCIENCE 121 
 
 slats of the length of a pencil, though sometimes of 
 several lengths, and sufficiently wide for making 
 from two to six pencils. The slats are grooved to 
 receive the lead and, when glued together, can be 
 cut into the corresponding number of pencils, which 
 are then smoothed by machinery, polished, stamped 
 with the letters indicating the degree of hardness, 
 and the makers' name, tied into bundles, and generally 
 prepared for sale. Coloured pencils are made from 
 special clay finely ground with colour, such as Prussian 
 blue, or vermilion, and mixed with a binding material, 
 pressed into sticks which are toughened by boiling 
 in a mixture of special fats and waxes before they are 
 placed in the slats. For copying-ink and indelible 
 pencils, an aniline dye is used, the colour being 
 soluble in water in order that impressions may be 
 taken on tissue paper. With the demand for pencils 
 steadily increasing and the supply of suitable cedar 
 becoming quickly exhausted, manufacturers will be 
 obliged to use other woods, or users must be content 
 with mechanical pencils. The industry is restricted 
 to comparatively few firms, the majority being of 
 long standing. Details of manufacture are largely 
 kept secret, but enough has been said to indicate that 
 the industry owes much to chemical science, in tho 
 selection, mixing, And general treatment of materials, 
 and to mechanical science in the invention of labour- 
 saving machinery for the processes involved. 
 
 Other domestic requirements, such as blacklead 
 (stove polish), and blacking, for leather, are now pro- 
 duced under scientific control. Black lead for produc- 
 ing a polished black surface on iron is made from the 
 massive graphite. Blacking is made of a variety of 
 materials and consists essentially of some black pig- 
 ment, such as animal charcoal (bone black), incorporated 
 with substances capable of taking a polish by friction. 
 A mixture of bone black, sperm oil, molasses and 
 vinegar forms a typical blacking, while other kinds 
 contain starch as ground material with tannate of 
 iron as colouring agent, and gum arabic as a binding 
 material. 
 
122 WHAT INDUSTRY OWES 
 
 CHAPTEB XVIII. 
 GASES. 
 
 IN the article on coal, we gave a brief description 
 of the manufacture and purification of one of its 
 principal decomposition products coal gas. Before 
 drawing our work to a conclusion, we propose to say 
 something of other gases, little known to those who 
 do not use them, and far simpler in their constitution 
 than coal gas. Discovered by science, their manu- 
 facture is the outcome of scientific investigation, and 
 not the mere retorting of a complex naturally 
 occurring substance. 
 
 The word gas is said to have been introduced by 
 the Flemish chemist, Van Helmont sixteenth cen- 
 tury being associated with the Dutch geest, a spirit 
 or ghost, Danish and German, geist, from the same 
 root as the Anglo-Saxon gaestlic, ghastly. To the 
 mediaeval mind, the air was a mystery, something 
 supernatural : it could not be seen or smelled, but 
 could be felt and heard. Gradually the idea of the 
 material nature of the air was developed by the 
 schools, but owing to the vague nature of the entity 
 concerned and the difficulty of handling it, little 
 progress was made with experimental investigation 
 until the middle of the seventeenth century. No 
 variety was recognised and everything of the nature 
 of air was classed as air, until the advent of methodical 
 experiment and logical deduction laid the foundations 
 of this fundamental department of knowledge. 
 
 A gas is physically the simplest form of matter ; the 
 laws governing its behaviour are less complex than those 
 regulating the conduct of solids and liquids. To the 
 recognition of this fact and the application of the 
 principle of defeating the weakest enemy first, science 
 
TO CHEMICAL SCIENCE 123 
 
 owes many of its most wonderful advances, such, for 
 instance, as we find in the application of the laws of 
 gases to substances in dilute solution. The extreme 
 fluid elasticity of gases and vapours and their high 
 co -efficient of thermal expansion render them 
 invaluable to the engineer. The nature of explosion, 
 the problems encountered in aeronautics, in meteoro- 
 logy, in the study of acoustics, are all closely connected 
 with the properties, both statical and dynamical, of 
 substances in the gaseous state. 
 
 Until the middle of the seventeenth century, the 
 philosophers students of nature affected to despise 
 experiment, their opinions being based on observation. 
 The alchemists seekers after the universal solvent, 
 the philosopher's stone and the elixir of life lovers 
 as they were of theory and mysticism, extolled the 
 experimental method by which they hoped to secure 
 wealth and the extension of life. Modern experi- 
 mental science may be considered as the outcome of 
 one of the controversies between two factions of the 
 former, combined with the overthrow of the methods 
 of the latter. A discussion arose between the plenists, 
 or Cartesians, who denied the possibility of a vacuum, 
 and the Vacuists,who maintained that there was no 
 reason why a vacuum should not exist. Robert 
 Boyle, born in 1626, " son of the Earl of Cork, and 
 the father of modern chemistry," flourished at the 
 time of the plenist controversy, and the problem 
 attracted him to physical science, especially the 
 study of the properties of air. In 1658 he constructed 
 the pneumatical machine ah* pump which was 
 destined to be of primary importance in many of 
 his subsequent experiments. His original aim being 
 to obtain a vacuum, he made with its aid some 
 significant discoveries. He demonstrated air pressure, 
 and elucidated the volume pressure relations of gases. 
 His law viz., that, at a constant temperature, the 
 volume of a given quantity of gas varies inversely as 
 the pressure was rediscovered independently a few 
 years later by Marriotte, a Frenchman. Boyle's 
 speculations on the chemical nature of air, founded on 
 many observations, including the gain in weight of 
 
124 WHAT INDUSTRY OWES 
 
 metals on calcination, contributed to the advance of 
 knowledge in his time, but the difficulty of pioneer 
 work on an invisible and almost intangible medium 
 limited such observations to the phenomena of 
 combustion and respiration. In 1661 appeared, 
 anonymously, " The Sceptical Chemist," a book which 
 criticised the teaching of the alchemists and depre- 
 cated their method of expression and the ambiguity 
 of their doctrines. As the author of this production 
 Boyle did much to sweep away the cobwebs of 
 mysticism. He was an early member of the 
 " Invisible College," a body much attacked in its 
 infancy for encouraging the investigation of Nature 
 then regarded by many as rank heresy which 
 eventually became our premier learned society, the 
 Royal Society of London. His researches were 
 mainly on " air," and there is little doubt that he 
 prepared the gases now known as hydrogen, carbon 
 dioxide, and hydrogen chloride ; but he did not 
 observe their characteristic properties. His work, 
 however, marked the beginning of a new era in 
 natural philosophy, his doctrine showing that scientific 
 advances were made not by theory or practice alone, 
 but by the application of both. 
 
 The discoveries and teachings of a genius have not 
 infrequently been overshadowed by those of a greater 
 and better -known contemporary. This was the case 
 with John Mayow, a medical practitioner of Bath, 
 who, in his experiments on air and his deductions 
 therefrom, was ahead of the workers of his time- He 
 recognised the existence of different kinds of gases in 
 the air, and prepared a gas nitric oxide by the 
 action of nitric acid on iron. He observed its action 
 on air, but failed to see the analytical possibilities of 
 the discovery. Boyle and Newton held the field in 
 natural philosophy, and Mayow received little 
 attention. Stephen Hales (1677-1761) prepared a 
 large number of gases, but regarded them all as 
 modifications of air, and failed to make use of the 
 facts he accumulated. When, however, Joseph 
 Black (1728-1799) discovered carbon dioxide, and 
 Daniel Rutherford (1749-1819) isolated nitrogen, both 
 
TO CHEMICAL SCIENCE 126 
 
 realised that these gases were distinct in their nature 
 from air. 
 
 Then followed the epoch-making discovery of 
 oxygen by Joseph Priestley and Carl Wilhelm 
 Scheele, a Swedish chemist, working independently. 
 Priestley also invented the eudiometer. Henry 
 Cavendish (1731-1810) made the first analysis of air, 
 devised the electric spark method of combining 
 nitrogen and oxygen, thus laying the foundation of 
 a very modern industry, and determined the com- 
 position of nitric acid. Cavendish proved the 
 compound nature of water ; determined its quanti- 
 titative composition, and also examined thoroughly 
 the fixed air carbon dioxide of Black. 
 
 All these eighteenth century investigators expressed 
 their views on the action of air and combustion in 
 terms of the phlogistic theory of Becher and Stahl, 
 and it remained for Antoine-Laurent Lavoisier, the 
 French savant, who fell a victim to the guillotine in 
 1794, to free them from this incubus and to develop 
 the new theory wherein oxygen was assigned its 
 proper rdle as a constituent of air and a supporter of 
 combustion. 
 
 Thus the composition of air as a mixture of oxygen 
 and nitrogen with small quantities of carbon dioxide 
 and water vapour and the explanation of the nature 
 of combustion were gradually established. To these 
 early workers, and especially to Priestley, Cavendish, 
 and Lavoisier, chemical science and industry owe an 
 irredeemable debt. Out of chaos they produced 
 order, and paved the way for the work of Avogadro, 
 Clark Maxwell, and Clausius. No new essential 
 constituents of air were discovered until the last 
 decade of the nineteenth century, when Rayleigh and 
 Ramsay, as an outcome of the measurements, by the 
 former, of the density of nitrogen from various sources, 
 including atmospheric, discovered five new chemically 
 inert gases Argon (without energy), Neon (new), 
 Helium (Sun), Krypton (hidden), and Xenon 
 (stranger) no compounds containing these elements 
 being as yet known. 
 
 Hydrogen. The discovery of hydrogen is usually 
 
126 WHAT INDUSTRY OWES 
 
 attributed to Paracelsus, a Swiss physician and 
 chemist fifteenth to sixteenth century. Its ex- 
 plosive properties were known to Lemery about 1700, 
 but it was not until seventy or eighty years later 
 that Cavendish demonstrated the individuality 
 of the gas, and showed its relation to water. It is 
 prepared in the laboratory by the action of a metal 
 such as zinc or iron on dilute sulphuric acid, this being, 
 in fact, the method by which it was first discovered, 
 and it is obtained in a much purer state, when neces- 
 sary, by the electrolysis of barium hydroxide. Traces 
 of oxygen are removed by passage over hot copper 
 shavings or platinised asbestos, the issuing gas being 
 dried by means of calcium chloride, or of phosphorus 
 pentoxide. 
 
 The properties of hydrogen bear no resemblance 
 to those of any other element. It is colourless, 
 odourless, tasteless, specifically lighter than any other 
 known substance, very sparingly soluble in water, and 
 capable of forming explosive mixtures with air or 
 oxygen, with chlorine and fluorine. It has also 
 the property, in the presence of finely-divided 
 metallic nickel, of combining with certain bodies 
 that are chemically unsaturated. Its density is 
 less than one -fourteenth that of air, and its lightness 
 and buoyancy render it of great value for use in 
 airships and balloons. Provided that it is sufficiently 
 pure, the two main advantages over coal gas for this 
 purpose are superior lifting power and the absence 
 of deleterious effect on the material of the envelope. 
 
 As a constituent of ammonia, hydrogen has in 
 recent years been largely used in Germany in a process 
 for the fixation of nitrogen, whereby the combination 
 of the two gases, under high pressure up to 200 
 atmospheres at a temperature of 500 deg. Gent., 
 is effected by the action of certain catalytic agents, 
 such as osmium, uranium, iron, manganese, or 
 tungsten. The efficiency of the catalysts is enhanced 
 by certain compounds of the alkali or alkaline earth 
 metals ; but catalyst " poisons " also exist, and these 
 are many and various. The gases must be freed 
 from these substances, the most obnoxious of which 
 
TO CHEMICAL SCIENCE 127 
 
 are compounds of sulphur and the hydrides of arsenic 
 and phosphorus. The ammonia is separated by 
 liquefaction, produced by strong cooling, or, in 
 certain cases, by solution in water. This process 
 was devised by Haber, is worked by the Badische 
 Anilin und Soda Fabrik, and promises to become 
 one of the chief methods of producing nitrogen. It 
 need not stop at this stage, however, for through the 
 work of Ostwald a mixture of air and ammonia gas, 
 under proper conditions, with platinum, as catalyst, 
 yields nitric acid, and the process may be developed 
 by proper regulation to yield ammonium nitrate, a 
 substance of high value as a fertiliser. 
 
 The third important use of hydrogen is, as we have 
 observed in a previous article, in the hardening of 
 fats, by direct action in the presence of finely-divided 
 metallic nickel. According to the method of Sabatier 
 and Senderens certain fine chemicals are now made by 
 the nickel method of hydrogenation, and this also 
 is likely to find extended application in industry. 
 
 With these developments it has become necessary 
 to find means of producing hydrogen in large quan- 
 tities at low cost. Owing to the expense of raw 
 materials, and the difficulty of securing a convenient 
 cycle of operations whereby the starting materials 
 may be recovered, production by the action of metals 
 on acids is not to much extent carried out on the 
 works scale, though the method may occasionally 
 be used for military purposes. Many patents have 
 been taken out for the manufacture, and we will 
 refer to some of the more important of them : 
 (1) By the action of steam on red hot iron, iron 
 oxide is formed, and hydrogen is set free. It is 
 then purified from dust, sulphur compounds, carbon 
 dioxide, &c., by suitable scrubbing treatment. 
 The iron oxide is reduced when necessary by replacing 
 the current of steam by one of water-gas, the residue 
 from this reaction being a source of nitrogen 
 Messerschmitt process. (2) By freeing water-gas 
 from carbon dioxide, by means of lime or caustic 
 soda, and subjecting the residue to the extreme cold 
 produced by boiling liquid air, nitrogen and carbon 
 
128 WHAT INDUSTRY OWES 
 
 monoxide are liquefied, leaving the hydrogen in the 
 gaseous state Linde-Frank-Caro process. (3) By 
 the electrolysis of the chloride or hydroxide of an 
 alkali. (4) The decomposition of acetylene prepared 
 from calcium carbide and water by heating 
 electrically. Hydrogen is prepared for Zeppelins 
 by this method, which yields also a valuable by- 
 product in the form of fine lampblack. (5) The gas 
 is also produced by a number of other patent methods, 
 mainly useful for military purposes. Hydrolith is 
 calcium hydride, prepared by the action of hydrogen 
 on calcium in the electric furnace, and on contact 
 with water, yields double the volume of hydrogen 
 originally expended in preparing it. Hydrogenite 
 is a mixture of five parts of ferrosilicon, four parts of 
 slaked lime, and twelve parts of caustic soda. When 
 heated locally a reaction takes place, and spreads 
 throughout the mass with evolution of hydrogen. 
 Both of these processes are due to Jaubert. 
 
 Oxygen, discovered by Priestley and Scheele, and 
 named by Lavoisier, occupies about one-fifth of 
 the volume of the atmosphere, and its properties as 
 a supporter of life and combiistion render it one of 
 the most important of the elements. It is also the 
 most abundant, representing about half the weight 
 of the solid crust of the earth, and roughly eight- 
 ninths of the water. It can be prepared in the labora- 
 tory by heating chlorate of potash either alone or 
 with manganese dioxide, by the action of sulphuric 
 acid on bichromates or permanganates, or by the 
 electrolysis of dilute sulphuric acid, or of solutions 
 of alkalies. On a commercial scale, Brin's process of 
 heating barium monoxide the analogue of lime 
 in dry, purified air to about 700 deg. Cent, under 
 10 Ib. pressure, for long held the field. The oxide 
 takes up oxygen, forming barium peroxide ; the 
 nitrogen is then pumped off, pressure being reduced 
 to about 2 Ib. Under these conditions the peroxide 
 gives up its excess of oxygen, which in turn is pumped 
 off and compressed into cylinders, reforming the 
 monoxide, which is available again for the same cycle 
 of changes. The method, however, has now been 
 
TO CHEMICAL SCIENCE 120 
 
 largely replaced by the liquid air process, which 
 depends for its utility on the ease with which air can 
 bo liquefied by the method of self-intensive cooling 
 introduced on the Continent by Linde and into 
 England by Hampson. Advantage is taken of the 
 fact that a compressed gas cools on expansion. Air 
 is compressed through a spiral, and allowed to escape 
 from a jet. On issuing it is cooled, and in turn 
 cools the air in the spiral by external contact. Thus 
 the issuing gas becomes increasingly colder, until 
 finally it issues from the jet in the liquid form. Liquid 
 oxygen and liquid nitrogen boil at different tempera- 
 tures, so that if the liquid air is fractionated the two 
 gases can be obtained in a fair state of purity. 
 
 Oxygen finds application in medicine, in the 
 chemical laboratory, and in the production of high 
 temperatures, such as are obtained by feeding 
 acetylene, hydrogen, and coal gas flames with the 
 gas. Oxy-acetylene cutting and welding, oxy- 
 hydrogen melting, including platinum working, the 
 autogenous soldering of lead, and the use of lime- 
 light, all depend on the production of an intensely hot 
 oxygen -fed flame. 
 
 Ozone is a colourless gas, condensable in liquid air 
 to a deep blue unstable liquid. Van Marum, in 1785, 
 and Schonbein, in 1840, observed a peculiar smell 
 in the neighbourhood of electrical machines in 
 motion, and the latter found that it was due to a 
 gas, which he named and found other means of 
 producing. Andrews, in 1856, showed that the 
 gas contained oxygen only, and Soret, in 1866, proved 
 its composition, which is represented by the formula 
 O 3 . It is prepared by the action of a silent electric 
 discharge on air or oxygen, a current of which is 
 passed through a special apparatus called an ozoniser. 
 The first of these was devised by Siemens in 1857, 
 and since that date numerous patents, founded 
 much on the same principle, have been recorded. 
 
 The commercial preparation resembles that on 
 the small scale. The pure substance is not obtained 
 in either case ; not more than 25 per cent, of the 
 oxygen is transformed into ozone under the best 
 
130 WHAT INDUSTRY OWES 
 
 conditions. The product is used in the sterilisation 
 of water and to a less extent of certain foods. 
 
 Acetylene was discovered in 1836 by Edmund Davy, 
 Professor at the Royal Dublin Society, during an 
 attempt to isolate potassium by heating calcined 
 tartar with carbon. He obtained a black mass, 
 which in contact with water gave rise to an inflam- 
 mable gas, and he suggested that if a cheap method 
 could be found for preparing it, the gas might well 
 be used as an illuminant. Its development as an 
 industrial commodity was not realised until over fifty 
 years later, but in the meantime several famous 
 names came into the literature of the subject, includ- 
 ing Hare, Berthelot, Wohler, Kekule, Vohl, and Sir 
 James Dewar. Hare unknowingly made calcium 
 carbide, and from it acetylene, by the action of 
 water. Berthelot prepared metallic acetylides, and 
 produced acetylene electrically from methane and 
 also from carbon and hydrogen. Wohler made 
 calcium carbide by heating an alloy of zinc and 
 calcium to a high temperature with carbon. Kekule 
 prepared acetylene by the electrolysis of the salts of 
 dibasic unsaturated organic acids. Vohl obtained 
 the gas by passing oils through red hot tubes, thereby 
 laying the foundation of our modern oil-cracking 
 processes. From American petroleum he obtained 
 a gas containing 20 per cent, of acetylene. Dewar 
 obtained acetylene by passing hydrogen through 
 tubes made of retort carbon heated to whiteness by 
 means of an electric current. 
 
 Acetylene is used, as we have already mentioned, 
 in one of the processes for making hydrogen ; as 
 an illuminant in isolated dwellings, and in motor 
 and bicycle lamps. It is invariably prepared by 
 the action of water on calcium carbide, which comes 
 on the market in the form of grey lumps, the product 
 of heating lime with carbon in the electric furnace. 
 The gas owes its position as an industrial product to 
 the development of the electric furnace by Siemens, 
 Bradbury, Oowles, and Moissan ; but the credit 
 for the realisation of the possibility of producing 
 calcium carbide on a commercial scale belongs to 
 
TO CHEMICAL SCIENCE 131 
 
 Willson, an American. In 1886, Cowles introduced 
 a furnace lining consisting of a mixture of lime and 
 carbon, and produced calcium carbide by the acci- 
 dental overheating of this lining. No attempt was 
 then made to utilise the discovery ; but, in 1892, 
 Willson, while working at Spray, with the object 
 of reducing lime to obtain calcium for the reduction 
 of alumina, prepared large quantities of the carbide, 
 and, realising the potentialities of the substance, set 
 up a works for its production. 
 
 Nitrogen, which forms about four-fifths of the air, 
 is produced by the methods we have already indi- 
 cated,* especially the Linde-Hampson process, and 
 is used in the synthetic preparation of ammonia, and 
 of cyanamido and cyanides, from calcium and 
 barium carbides respectively. 
 
 Chlorine, discovered by Scheele in 1774, and pro- 
 nounced an element by Davy in 1810, is a heavy 
 yellow poisonous gas of an extremely irritating 
 odour. It is largely used in the sterilisation of water 
 and in gold extraction, and has been employed as 
 poison gas during the war. It is prepared by the 
 action of manganese dioxide on hydrochloric acid, 
 the oxide being recovered by the Weldon process. 
 It may be converted into bleaching powder, through 
 its absorption by lime, or liquefied by cold and pres- 
 sure and stored in steel cylinders. 
 
 Carbon Dioxide, or carbonic acid gas, a waste 
 product of the brewery, is used for aerating beer and 
 mineral waters, and is sometimes employed as a 
 freezing agent. 
 
 Carbonyl Chloride, or phosgene, prepared by the 
 interaction of chlorine and carbon monoxide in the 
 presence of animal charcoal, or of antimony penta- 
 chloride, or by the action of fuming sulphuric acid 
 on carbon tetrachloride, is used in the manufacture 
 of dyes, and has also been employed as a poison gas. 
 
 Laughing Gas, or nitrous oxide, is made by heating 
 ammonium nitrate. It was discovered by Priestley 
 in 1772, and is used as an anaesthetic in dentistry. 
 
 * Refer to Agriculture and Hydrogen. 
 
132 WHAT INDUSTRY OWES 
 
 We do not need to dilate on the relation between 
 science and these products which are so obviously 
 scientific in their conception, elucidation and deve- 
 lopment 
 
TO CHEMICAL SCIENCE 133 
 
 CHAPTER XIX. 
 GOVERNMENT CHEMISTRY. 
 
 IN the article dealing with Agriculture and Food, 
 we have referred to the official agricultural analysts 
 and public analysts, who are appointed under statutes 
 to safeguard the quality of supplies of fertilisers and 
 feeding stuffs, food and drugs ; and we will now refer 
 to other official chemists directly or indirectly 
 concerned with industry. 
 
 In 1843 a laboratory was established at Somerset 
 House, in connection with the Inland Revenue 
 Department, to check adulteration of tobacco, and 
 later a second laboratory was established at the 
 Custom House for the examination of wines, spirits, 
 and other imported articles liable to duty. In 1894 
 the control of these laboratories was entrusted to 
 one Principal, and in 1897 the Excise Branch was 
 transferred to a new building at Clement's Inn -passage. 
 In 1911 the Government Laboratory was constituted 
 an independent department under the Treasury, with 
 a separate Parliamentary Vote, entitled " Government 
 Chemist." The Laboratory undertakes investiga- 
 tions for every other Government Department, the 
 greater part being carried out at Clement's Inn- 
 passage, and in the branch laboratory at the Custom 
 House. The Government Chemist also controls 
 eighteen stations in different parts of the United 
 Kingdom, where tests are made for revenue purposes. 
 From a recent report, we gather that the work for the 
 Department of Customs and Excise relates, mainly, 
 to the assessment of duty and drawback, and to regula- 
 tions and licences, in connect/ion with the manufacture 
 and sale of dutiable articles, such as beer, spirits, 
 wine, tobacco, tea, sugar, coffee, cocoa, and prepara- 
 tions advertised for the cure or relief of human 
 
 K 2 
 
134 WHAT INDUSTRY OWES 
 
 ailments commonly called " patent medicines." 
 The work for the Admiralty includes the examination 
 of food substances, the analysis of metals and of 
 contract stores ; that for the Board of Agriculture 
 and Fisheries refers largely to imported dairy produce 
 and margarine, and includes for the Fisheries 
 Division samples of river water believed to have 
 been polluted and to have caused injury to fish, as 
 well as the determination of the salinities of samples 
 of sea water for the Permanent International Council 
 for Exploration of the Sea. Samples of beer and 
 whiskey are examined for the Central Control Board 
 (Liquor Traffic) ; and of drugs, pharmaceuticals 
 and contract supplies for the Ciown Agents for the 
 Colonies. Fire-clay and limestone from various 
 districts are examined for the Geological Survey ; 
 lead glazes and enamels for the Home-office ; drugs 
 for the India-office, and stamps and inks ior the 
 Board of Inland Revenue. Investigations on pre- 
 servatives in food are carried out for the Local 
 Government Board ; and on paper, pigments, gum, 
 engineering and general stores for the Post-office ; 
 ink and typewriter ribbons for the Stationery-office ; 
 lighthouse stores for the Corporation of Trinity 
 House ; lime and lemon juice and ship's stores for the 
 Board of Trade ; food supplies for the Army, drugs 
 and surgical dressings, for the Army Medical Depart- 
 ment, for the War-office ; samples of varied character 
 for the War Trade Department ; samples of water for 
 the Office of Woods and Forests ; of contractors' 
 supplies and of water for the Offices of Works 
 London and Dublin ; and samples referred by the 
 magistrates under the Sale of Food and Drugs Acts, 
 1875 and 1899, and submitted by the Board of 
 Agriculture, under the Fertilisers and Feeding Stuffs 
 Act. The total number of samples examined during 
 the year ended March 31st, 1916, was 383,892. The 
 work has obviously an important bearing on industry 
 and commerce, and entails the employment of a 
 large technical staff, of which many members are 
 required to be highly trained and competent chemists. 
 As illustrating the value of their work, we may refer 
 
TO CHEMICAL SCIENCE 135 
 
 to the examination of food for the armies in the field 
 during the war, work essential in the interests both 
 of the health of the troops and of the Exchequer. 
 The food must be wholesome ; but the findings of the 
 chemists will determine the cash value of the supplies : 
 a deviation of, say, 1 or 2 per cent, of moisture in 
 flour, biscuits or margarine, may involve a reduction 
 of hundreds of pounds on a single contract. 
 
 Although the Government Laboratory constantly 
 advises other departments, some possess their own 
 laboratories for special purposes. The Admiralty has 
 a staff under the Admiralty Chemist, and einploys 
 chemists in connection with the examination of 
 various materials of construction and victualling 
 stores. The Admiralty has also its duly appointed 
 Adviser on Petroleum, as well as officers .possessing 
 special scientific experience, and professors of 
 chemistry in the Royal Naval Colleges. The War- 
 office, too, makes good use of chemists, in many 
 matters arising out of the conditions of modern war- 
 fare, and instruction in chemistry is given m the 
 Royal Ordnance College, the Royal Army Medical 
 College, the Royal Military Academy, and other 
 establishments. Under the Ministry of Munitions, 
 in addition to chemists engaged in an advisory capa- 
 city, there are considerable numbers in charge of the 
 production of explosives in Government and con- 
 trolled factories, and special staffs are appointed 
 for research and inspection work. 
 
 Official analysts are appointed to the Home -office 
 for toxicological work, as well as in connection with 
 the Explosives Department and the Factory Depart- 
 ment. The Local Government Board possesses a 
 Department for the inspection of food and a staff of 
 specially qualified inspectors to assist in the adminis- 
 tration of the Alkali, &c., Works Regulation Act. 
 The Metropolitan Water Board and the Rivers Boards 
 in various parts of the country have their chemical 
 and bacteriological laboratories, and so have the 
 Sewage Boards and Works. The Scottish Office also 
 appoints inspectors under the Alkali Act and Rivers 
 Pollution Prevention Act. 
 
136 WHAT INDUSTRY OWES 
 
 The London County Council controls a consider- 
 able staff for chemical investigations, including gas 
 testing, and the Board of Trade appoints the Gas 
 Referees, in accordance with the Metropolis Gas 
 Acts, to prescribe the apparatus and materials 
 to be employed for testing the illuminating power, 
 calorific power, purity and pressure of the gas, 
 the mode of testing, and, in certain cases, the times 
 of testing, the current prescriptions being published 
 in the " Notification of Gas Referees." Other county 
 and borough authorities make provision for the inspec- 
 tion of water and gas supplies. Chemists are also 
 included in the staff of the Patent-office, and Assayers 
 render responsible service in the Royal Mint and 
 at the Assay Offices, as well as for the Bank of 
 England. 
 
 The Scientific and Technical Department of the 
 Imperial Institute conducts investigations for the 
 Indian and Colonial Government. , chiefly relating to 
 the composition and utilisation of raw materials. 
 The National Physical Laboratory includes a Depart- 
 ment of Metallurgy and Metallurgical Chemistry. 
 Laboratories are attached to many public Institu- 
 tions, such as the Davy-Faraday Research Laboratory 
 of the Royal Institution, and those of the Lister 
 Institute and the Royal Dublin Society. 
 
 The existence of this extent of official organisation 
 in chemistry is little known to the general public, 
 but it is obviously indispensable to the well-being 
 of the community. The personnel of our chemical 
 service includes many men of science of high repute 
 in their professions who deserve well of their country, 
 and it is essential that the conditions attaching to 
 this service should be such that it will continue to 
 attract chemists of the highest competence. We have 
 endeavoured to make this list fairly comprehensive, 
 but have not referred to India and the Overseas 
 Dominions, where many chemists hold appointments 
 analogous to those we have indicated ; nor have we 
 referred to the valuable work carried out by analysts 
 in hospitals and public health laboratories, or the 
 appointments held in the Universities and Technical 
 
TO CHEMICAL SCIENCE 137 
 
 Colleges, to which we look for the continued supply 
 of lieutenants to meet our requirements in the various 
 branches of chemical practice. 
 
138 WHAT INDUSTRY OWES 
 
 CONCLUSION. 
 
 WHILE we have confined our attention mainly to 
 the debts of industry to chemical science, we do not 
 suggest that those due to physical and mechanical 
 science should not be similarly acknowledged. 
 
 The art of engineering has been steadily built up 
 through the ages, but modern developments are, 
 in the main, directly attributable to the advance 
 of science. In chemical industries, however, the 
 processes of manufacture, in many cases, preceded 
 the discovery of the scientific principles on which they 
 were based. The ironmaster, the dyer, the soap 
 and candle maker, the tanner, the potter, and the 
 glass manufacturer, were in existence centuries 
 before serious attention was paid to the science under- 
 lying their work. Conventions die hard, and for 
 a long time there was little enthusiasm to take advan- 
 tage of what science had to offer. It is freely admitted 
 that the state of civilisation attained before the advent 
 of modern science was far removed from the conditions 
 of life of primitive man ; but it is claimed that 
 while science was so little developed, industry had 
 to look to experience as the only basis to work upon. 
 Experience, accumulated slowly and at great cost, 
 had done great things ; but the rate of progress 
 in industry developed in the past century defies 
 comparison with all the centuries combined since 
 time was so far as we know ! Still, let us admit that 
 the inheritance was great, and that even the alchemist 
 preserved much that was good in chemistry, just 
 as the monks of the Middle Ages preserved much 
 that was good in classical literature and architecture. 
 We have endeavoured to indicate the interdependence 
 of science and industry on one another, and to show 
 how frequently science " the nursling of interest 
 and the daughter of curiosity " pursued for her 
 
TO CHEMICAL SCIENCE 139 
 
 own sake, has sooner or later proved her practical 
 utility. Incidentally we have shown that though 
 " Genius is of no country," British men of science, 
 often in the face of small encouragement, have played 
 their part in industrial development. There is 
 no reason to depreciate the value of their work, or to 
 pay much attention to the Jeremiahs who seem to 
 delight in bemoaning the industrial and commercial 
 position of this country but are seldom able to offer 
 any constructive criticism. 
 
 Advancement may be the outcome of the labours of 
 the consultant, the chemist on the works, the official 
 chemist, or the professor ; all have contributed their 
 share to discovery and invention. In any case, it is 
 certain that our industries have utilised their know- 
 ledge, skill and experience to a greater extent than 
 has been generally recognised ; otherwise much that 
 has been done in the last three years would have been 
 impossible, and our position would have been far worse 
 than It is. 
 
 We feel that the apathy towards science prevailing 
 before the war was more imaginary than real and, 
 such as it was, is being overcome ; that the general 
 public is beginning to realise something of the 
 importance of science in the affairs of everyday life, 
 and that the time is at hand when the services of 
 the man of science will be better understood and 
 consequently more substantially rewarded. The 
 men of science themselves are increasing in number 
 and influence ; their work lies more and more in the 
 control of large scale operations, as well as in the 
 laboratory. The time has passed when men feared 
 to probe into the truth as if it were sacrilege, or to 
 imagine things beyond certain knowledge and estab- 
 lished fact, or to explore into realms of not only the 
 improbable but the seemingly impossible, whence so 
 much, with the aid of science, has been and is yet to 
 be derived. 
 
 To-day, the arts and sciences go hand in hand : 
 the engineer and the chemist, each recognising the 
 limits of his own domain, though the line dividing them 
 may often be difficult to define, co-operate with one 
 
140 WHAT INDUSTRY OWES 
 
 another and mutually assist in the solution of indus- 
 trial problems. Now is the time for leaders of indus- 
 try to see to it that the opportunity is taken of making 
 good, wherever possible, the connecting link between 
 science and practice. A thorough overhauling of 
 n ethods and plant should keep our consulting 
 chemists and engineers well employed in preparation 
 for the future. There is no lack of good men, and 
 soon there will be enough and to spare for permanent 
 appointments on the works. 
 
 If in these articles we have been successful in 
 indicating some of the triumphs of science in industry, 
 and if our efforts have in any way conduced to a better 
 realisation of the value of scientific thought and 
 method, we may rest satisfied that our labour has not 
 been in vain. 
 
TO CHEMICAL SCIENCE 141 
 
 BIBLIOGRAPHY. 
 
 BACON and HAMOR. The American Petroleum Industry. 
 New York, 1916. 
 
 BAKER, J. L. The Brewing Industry. London, 1905. 
 
 BLOUNT, B. Cement. Lecture, Institute of Chemistry, 
 London, 1912. 
 
 BLOUNT and BLOXAM. Chemistry for Engineers and 
 Manufacturers. London, 1910-1911. 
 
 BLOXAM, C. L. Chemistry, Inorganic and Organic. 
 Edited by A. G. Bloxam and S. Judd Lewis. London, 1913. 
 
 BORCHERS, W. Electric Smelting and Refining. London, 
 1904. 
 
 BORCHERS, W. Metallurgy. Translated by W. T. 
 Hall and C. R. Hayward. London and New York, 1911. 
 
 BROWN, J. CAMPBELL. History of Chemistry from the 
 Earliest Times to the Present Day. London, 1913. 
 
 BURGESS and LE CHATELIER. The Measurement of 
 High Temperatures. New York, 1912. 
 
 BUTTERFIELD, W. J. A. Chemistry in Gas Works. 
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 BYROM and CHRISTOPHER. Modern Coking Practice. 
 London, 1910. 
 
 CAIN and THORPE. The Synthetic Dyestuffs and the 
 Intermediate Products from which they are derived. London, 
 1917. 
 
 CHAPMAN, A. CH ASTON. Brewing. Cambridge, 1912. 
 
 CROSS, C. F. Cellulose. Lecture, Institute of Chemistry. 
 London, 1912. 
 
 CROSS and BEVAN. Researches on Cellulose, 1895/1910. 
 London, 1901-1912. 
 
 A Text-book of Papermaking. London, 1907. 
 
 DREAPER, W. P. The Research Chemist in the Works 
 with Special Reference to the Textile Industry. Lecture, 
 Institute of Chemistry. London, 1914. 
 
 ENGLER and HOFER. Das Erdol. Leipzig, 1909 -f. 
 
 FINDLAY, ALEXANDER. Chemistry in the Service of 
 Man. London, 1917. 
 
 HARBORD and HALL. The Metallurgy of Steel. London, 
 1916. 
 
142 WHAT INDUSTRY OWES 
 
 HERRICK, R. F. Denatured or Industrial Alcohol. New 
 York, 1907. 
 
 HILDITCH, T. P. A Concise History of Chemistry. 
 London, 1911. 
 
 HILL, C. A. The Function and Scope of the Chemist in 
 a Pharmaceutical Works. Lecture, Institute of Chemistry. 
 London, 1913. 
 
 LAFAR, FRANZ. Technical Mycology. London, 1910. 
 
 LEEDS and BUTTERFIELD. Acetylene. London, 1910. 
 
 LEWKOWITSCH, J. Chemical Technology of Oils, Fats 
 and Waxes London, 1913-1915. 
 
 Loins, HENRY. The Dressing of Minerals. London, 
 1909. 
 
 LUNGE, GEORGE. Coal Tar and Ammonia. London, 
 1916. 
 
 Sulphuric Acid and Alkali. London, 1911. 
 
 MACNAB, WILLIAM. Explosives. Lecture, Institute of 
 Chemistry. London, 1914. 
 
 MCMILLAN, W. G. A Treatise on Electro -Metallurgy. 
 London, 1899. 
 
 MARSHALL, ARTHUR. Explosives. London, 1917. 
 
 MELLOR, J. W. Treatise on Quantitative Inorganic 
 Analysis. London, 1913. 
 
 MEYER, ERNST VON. A History of Chemistry from 
 Earliest Times to the Present Day. Translated by George 
 McGowan. London, 1906. 
 
 MIERS, Sir H. A. Mineralogy. London, 1902. 
 
 NEWLANDS, B. E. R. Sugar. London, 1913. 
 
 PORRITT, B. D. The Chemistry of Rubber. London, 
 1913. 
 
 PRICE, T. SLATER. Per-acids and their Salts. London, 
 1912. 
 
 PROCTER, H. R. The Principles of Leather Manufacture. 
 London, 1903. 
 
 RAMSAY, SIR WILLIAM. The Gases of the Atmosphere, 
 the History of their Discovery. London, 1915. 
 
 REDWOOD, Sir BOVERTON, Bart. Petroleum. London, 
 1913. 
 
 ROBERTS- AUSTEN, Sir W. C. Introduction to the Study of 
 Metallurgy. London, 1910. 
 
 ROSCOE (Sir H. E.) and SCHORLEMMER. Treatise on 
 Chemistry. London, 1911-1913. 
 
 ROSE, Sir T. KIRKE. The Metallurgy of Gold. London, 
 1915. 
 
 STANSFIELD, ALFRED. The Electric Furnace. New 
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TO CHEMICAL SCIENCE 143 
 
 TERRY, HUBERT L. India-rubber and its Manufacture. 
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 THORPE, Sir EDWARD. A Dictionary of Applied 
 Chemistry. London, 1912. 
 History of Chemistry. London, 1909-10. 
 
 TILDEN, Sir WILLIAM A. Chemical Discovery and 
 Invention in the, Twentieth Century. London, 1916. 
 
 TROTMAN, S. R. Leather Trades Chemistry. London, 
 1908. 
 
 TURNER, T. The Metallurgy of Iron. London, 1915. 
 
 WHITE, EDMUND. Thorium. Lecture, Institute of 
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 WOOD, JOSEPH TURNEY. The Puering, Bating, and 
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 WRIGHT, S. B. A Practical Handbook on the Distillation 
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144 
 
 WHAT INDUSTRY OWES 
 
 IN DEX. 
 
 ABBE, 71 
 
 Abel, 46 
 
 Acetic Acid, 81 
 
 Acetone, 86 
 
 Acetylene, 130 
 
 Acetylsalicylic Anhydride, 89 
 
 Achard, 20, 101 
 
 Acheson, 67, 69 
 
 Acids, 80 
 
 Agriculture, 95 
 
 Alcohol, 84, 109 
 
 , Absolute, 110 
 
 , Denaturing of, 110 
 
 Alizarin, 43 
 
 Alkali Act, 30 
 
 Manufacture, 27 
 
 , Manufacture by Elec- 
 trolysis, 32 
 
 Waste, 29 
 
 Alum-tan, 61 
 
 Aluminium, 15 
 
 Alundum, 69 
 
 Ammonal, 47 
 
 Ammonia, 37 
 
 Gas, 103 
 
 Ammonia -soda Process, 31 
 
 Ammoniacal Copper Solution. 
 84 
 
 Ammonium Salts, 83 
 
 Sulphate, 23 
 
 Anaesthetics, 85 
 
 , Local, 89 
 
 Analytical Re-agents, 87 
 
 Andrews, 129 
 
 Aniline, 44 
 
 Anthracene, 40 
 
 Antifebrin, 89 
 
 Antimony Salts, 84 
 
 Antipyretics, 89 
 Antiseptics, 89 
 Archer, 91 
 Arsenic Acid, 81 
 
 , Organic Compounds of, 
 
 89 
 
 Aspirin, 81, 88 
 Astatki, 55 
 Atoxyl, 89 
 Atropine, 88 
 
 BACON, Roger, 45 
 Bactericidal Agents, 89 
 Barium, Peroxide, 83 
 
 Salts, 83 
 
 Bases, 81 
 Basic Slag, 98 
 Beer, 104 
 Benzene, 39 
 Benzine, 54 
 Benzoic Acid, 81 
 Bernard Freres, 16 
 Berthelot, 130 
 Berzelius, 17 
 Bessemer, 3 
 Bevan, 52 
 
 Bieberich Scarlet, 42, 43 
 Birkeland and Eyde, 97 
 Bismuth Salts, 84 
 Black, 124 
 Blacking, 121 
 Black Lead, 121 
 Blast Furnaces, Water- 
 jacketed, 10 
 Blasting Gelatine, 47 
 Bleaching Powder, 30 
 Blue Prints, 93 
 
TO CHEMICAL SCIENCE 
 
 145 
 
 Boric Acid, 81 
 
 Botticher, 78 
 
 Bouchardat, 64 
 
 Boullay, 86 
 
 Boyle, 35, 90, 123 
 
 Braconnot, 45 
 
 Bradbury, 130 
 
 Brandy, 113 
 
 Brewing, 104 
 
 Erin's Process, 128 . 
 
 Brown, A. J., 107 
 
 Brunner, 15 
 
 Brunner, Mond and Co., 32 
 
 Buchner, 107 
 
 Bunsen, 15 
 
 Butadiene, 64 
 
 Butter Substitutes, 58 
 
 CALLENDAR, 79 
 Calomel, 83 
 Calotype Process, 91 
 Camphor, 55 
 Candles, 57 
 Caoutchouc, 63 
 Carbohydrates, 48 
 Carbolic Acid, 39 
 Carbon Bisulphide, 84 
 Carbonic Acid Gas, 103, 108 
 Carbon Printing Process, 93 
 
 Tetrachloride, 85 
 
 Carbonyl Chloride, 131 
 Carborundum, 69 
 Castner, 15, 32 
 Catalyst, Poisoning of, 26 
 Catalytic Agents, 31 
 Cattermole, 8 
 Caustic Potash, 81 
 
 Soda, 28, 81 
 
 Cavendish, 125, 126 
 Caventou, 88 
 Cellon, 52 
 Celluloid, 52 
 Cellulose, 48 
 Cement, 65 
 Cementation, 2, 3 
 
 Chamois Leather, 61 
 Chance-Claus Method, 29 
 de Chardonnet, 51 
 Chevreul, 56 
 Chloral, 86 
 Chlorates, 33 
 Chlorate of Potash, 30, 
 Chlorine, 131 
 
 , Recovery of, 30, 32 
 
 Chloroform, 85 
 Chrome-tan, 61 
 Chromium, 17 
 
 Cinnamoylsalicylic Anhy- 
 dride, 89 
 Citric Acid, 80 
 Clark (Water Treatment), 6 
 Claudet, 29 
 Claus, 29 
 Clayton, 35 
 Cleaning Spirit, 54 
 Coal, 34 
 Coal-gas, 35 
 Coal Tar, 36 
 Cocaine, 89 
 Cochineal, 41 
 Coke, 34 
 
 Cold Storage, 103 
 Colloidal State, 61 
 Colour Photography, 93 
 Contact Agents, 31 
 
 Process, 26 
 
 Conte, 120 
 Cookworthy, 65, 78 
 Copper, 10 
 
 in Pyrites, 29 
 
 , Salts, 84 
 
 Cordite, 46 
 
 Corrosive Sublimate, 83 
 Cowles, 130, 131 
 Cresylic Acid, 39 
 Cronstedt, 14 
 Crookes, 97 
 Cross and Be van, 52 
 Cyanamide Process, 97 
 Cyanamides, 83 
 Cyanides, 62, 83, 97 
 Cymogene, 54, 103 
 
146 
 
 WHAT INDUSTRY OWES 
 
 DAGUERRE, 90 
 
 Dale, 48 
 
 D'Arcet, 20 
 
 Davy, Edmund, 130 
 
 Davy, H., 15, 16, 25, 81, 90, 
 
 131 
 
 Deacon, 31 
 Debray, 20 
 Delprat, 8 
 Descotils, 20 
 Desmond, 61 
 Deville, 15, 17, 20 
 Dewar, 130 
 Diastase, 106 
 
 Diffusion Process, 101, 102 
 Disinfectants, 89 
 Dobereiner, 71 
 Dowson Gas, 35 
 Drugs, 88 
 Dry Plates, 92 
 Dye Industry, 41 
 Dyeing, 44 
 
 Dyer and Hemming, 32 
 Dyes, Artificial ; Advantages 
 
 of, 42 
 Dynamite, 47 
 
 EGGS, Preservation of, 83 
 Ehrlich, 89 
 Eitner, 62 
 Elmore, 7, 8 
 Elution, Process, 102 
 Enamels, 75 
 Epsom Salts, 83 
 Esparto, 50 
 Essential Oils, 55 
 Ether, 86 
 
 , Extraction by, 12 
 
 Everson, 7 
 Explosives, 44 
 
 FATS, 53 
 
 Feeding-stuffs, 98 
 Fermentation, 107 
 Ferrochrome, 17 
 Ferromanganese, 3 
 
 Ferro vanadium, 19 
 
 Fertilisers, 95 
 
 Fertilisers and Feeding Stuffs 
 
 Act, 98 
 F&y, 79 
 
 Filaments, Electric Lamp, 17 
 Fine Chemicals, 86 
 Fire-extinguisher, 85 
 Fleurscheim, 47 
 Flotation of Minerals, 7 
 Food, 95, 99 
 Formic Acid, 80 
 Fox Talbot, 91 
 Fraunhofer, 71 
 Freezing Agents, 103 
 Fuel, Economy of, 6 
 Fusel Oil, 114 
 
 CANISTER, 69 
 Gas Carbon, 37, 69 
 
 , Illuminating, 34, 54 
 
 Gas Light and Coke Co., 36 
 Gasolene, 54 
 Gay-Lussae, 25, 48 
 Gelatine Dynamite, 47 
 Glass, 70 
 
 , Etching of, 81 
 
 , Optical, 71 
 
 , Resistant, 72 
 
 for Thermometers, 72 
 
 Gin, 114 
 Glover, 25 
 Glucose, 106 
 Glue, 62 
 Glycerine, 56 
 Gold, 19 
 
 in Pyrites, 29 
 
 Salts, 84 
 
 Goodyear, 63 
 
 Gossage, 30 
 
 Government Chemistry, 133 
 
 Graham, 102 
 
 Graphite, 69, 119, 120 
 
 Ores, 7 
 
 Guinand, 71 
 Guncotton, 45 
 
TO CHEMICAL SCIENCE 
 
 147 
 
 Gunpowder, 45 
 Guthrie, 85 
 
 HABER'S Process, 126 
 Hadfield, 5 
 Hales, 124 
 Hampson, 129 
 Hancock, 63 
 Harcourt, 71 
 Harden, 107 
 Hardening of Oils, 14 
 Hare, 20, 130 
 Harries, 64 
 Heinzerling, 62 
 Hemming, 32 
 Henderson, 29 
 Herschel, 91 
 Heumann, 43 
 Hides, Treatment of, 60 
 Hops, 106 
 Huntsman, 2 
 Hydrochloric Acid, 30 
 Hydroflouric Acid, 81 
 Hydrogen, 125 
 Hydrogen Peroxide, 83 
 Hydrogenite, 128 
 Hydrolith, 128 
 Hyoscine, 88 
 Hyoscyamine, 88 
 Hypo, 83 
 Hypochlorites, 33 
 
 INDIGO, 42 
 
 , Artificial, 25 
 
 Inks, 117 
 Insecticides, 89 
 Invert Sugar, 106 
 Iridium, 20 
 Iron Sulphate, 84 
 Isoprene, 63 
 
 JACKSON, C., 86 
 Janetty/20 ' 
 
 Jaubert, 128 
 
 Johnson, Matthey and Co., 20 
 
 KAINITE, 82 
 Kekule, 130 
 Kerosene, 54 
 Kestner, 24 
 Knapp, 62 
 Knight, 20 
 
 LACTIC Acid, 80, 113 
 Lamp Oil, 54 
 Lampadius, 84 
 Laughing Gas, 83, 131 
 Laurent, 47 
 Lavoisier, 125 
 Lawrence, 85 
 Lead Azide, 84 
 
 Carbonate, 84 
 
 Chamber Process, 24 
 
 , Desilverisation of. 11 
 
 , Purity of, 13 
 
 Leather, 59 
 
 Leather Cloth, 62 
 
 Leblanc, 27 
 
 Le Bon, 36 
 
 Le Chatelier, 4, 65, 79 
 
 Lefevre, 24 
 
 Lemery, 24, 126 
 
 Liebig, 107 
 
 Lignocellulose, 50 
 
 Ligroin, 54 
 
 Linde, 129 
 
 Linde-Frank-Caro Process, 
 
 128 
 
 Lipmann, 93 
 Liqueurs, 114 
 Liquid Air Process, 129 
 Lumiere, 93 
 Lupulin, 106 
 Lyddite, 47 
 
 MAC ARTHUR-FORREST, 19 
 Macintosh, 63 
 
148 
 
 WHAT INDUSTRY OWES 
 
 Madder, 42 
 Magnalium, 16 
 Magnesia, 82 
 Magnesium, 16 
 
 Sulphate, 83 
 
 Magnetic Separation, 10 
 
 Malt, 105 
 
 Mantles, Gas, 18 
 
 Marggraf, 101 
 
 Marriotte, 123 
 
 Martens, 4 
 
 Matthews, 64 
 
 Mauveine, 44 
 
 Mayow, 124 
 
 McDougall and Howies, 97 
 
 Melinite, 47 
 
 Mercury Fulminate, 83 
 
 Messerschmitt Process, 127 
 
 Metallography, 4 
 
 Methyl Alcohol, 110 
 
 Methyl Chloride, 103 
 
 Mineral Tannages, 61 
 
 Minerals, Separation of, 7 
 
 Moissan, 17, 130 
 
 Molybdenum, 16 
 
 Monazite, 18 
 
 Mond. 14, 32 
 
 Gas, 35 
 
 Mordants, 44 
 Mortar, 65 
 Motor Spirit, 54 
 Murdock, 35 
 31uspratt, 27 
 
 NEOSALVARSAN, 89 
 Nickel, 14 
 Nicotine, 116, 117 
 Niepce, 90 
 Nitrides, 97 
 Nitrogen, 131 
 , Fixation of, 96 
 
 Nitroglycerine, 46 
 
 Nobel, 46 
 
 Nordhausen, 26 
 
 Novocaine, 89 
 
 OILS, Animal, 55 
 
 , Hardening of, 14 
 
 , Vegetable, 55 
 
 Osmium, 20 
 Osmond, 4 
 Osmose Process, 102 
 Ostwald, 127 
 Oxalic Acid, 48, 80 
 Oxygen, 128 
 Ozone, 129 
 
 PALLADIUM, 21 
 
 Paper, 49 
 
 Paracelsus, 126 
 
 Paraffin Wax, 54 
 
 Parker, 66 
 
 Parkes, 11, 12, 13 
 
 Parting of Gold, 20 
 
 Pasteur, 107 
 
 Pattinson, 11 
 
 Pelletier, 88 
 
 Pencils, 119 
 
 Percarbonates, 83 
 
 Perfumes, 56 
 
 Perkin, 44, 64 
 
 Peroxy Compounds, 83 
 
 Persulphates, 83 
 
 Petrol, 54 
 
 Petroleum, Distillation of, 54 
 
 Phenacetin, 89 
 
 Phosgene, 131 
 
 Photographic Materials, 94 
 
 Photography, 90 
 
 Piat, 63 
 
 Picric Acid, 47 
 
 Pitch, 36 
 
 Platinum, 20 
 
 Salts, 84 
 
 Plattner, 19 
 
 Plenist Controversy, 123 
 Plumbago, 119 
 Poison Gases, 131 
 Porcelain, 77 
 Potassium Salts, 81 
 
 Thiocarbonate, 85 
 
 Pott, 78 
 
TO CHEMICAL SCIENCE 
 
 149 
 
 Potter, 8 
 
 Potter's Cones, 78 
 Pottery, 77 
 Priestley, 63, 125, 131 
 Procter, 59, 62 
 Puering, 60 
 Pulvis Fulminans, 45 
 Pyrometer, 79 
 
 QUININE, 88 
 
 RAMSAY, 125 
 Rayleigh, 125 
 Refractory Materials, 68 
 Reid, 46 
 Rhigolene, 54 
 Rhodium, 21 
 Roberts -Austin, 4 
 Roebuck, 24 
 Rolland, 32 
 Rubber, 63 
 
 , Synthetic, 64 
 
 Rum, 114 
 Rutherford, 124 
 
 SABATIEB, 127 
 
 Salicylic Acid, 81, 88 
 
 Salipyrene, 89 
 
 Salts, 82 
 
 Salvarsan, 89 
 
 Sauveur, 4 
 
 Scheele, 20, 90, 125, 131 
 
 Scheibler, 102 
 
 Schloessing, 32 
 
 Schonbein, 45 
 
 Schott, 71 
 
 Schultz, 62 
 
 Sefstrom, 19 
 
 Seguin, 61 
 
 Senderens, 127 
 
 Separation, Magnetic, 10 
 
 Sepia, 41 
 
 Shale Oil, 55 
 
 Shimose, 47 
 
 Sicoid, 52 
 
 Siemens, 4, 129, 130 
 
 and Halske, 20 
 
 Silica, Fused, 69, 73 
 Silicon, 69 
 
 Silk, Artificial, 48, 5 1 
 Silver in Pyrites, 29 
 
 Salts, 84 
 
 Simmonds, 79 
 Simpson, 85 
 Smeaton, 65 
 Smelling Salts, 83 
 Soap, 56 
 Sobrero,.46 
 Soda Ash, 28 
 Sodium, 15 
 
 Bicarbonate, 28, 31 
 
 Carbonate, 28 
 
 Salts, 83 
 
 Peroxide, 83 
 
 Solar Oils, 55 
 
 Solvay, 28, 31, 32 
 
 Solvents, 84 
 
 Sorby, 4 
 
 Soret, 129 
 
 Souberain, 85 
 
 Spiegel, 3 
 
 Spirits, 112 
 
 Stead, 4 
 
 Steel, 2 
 
 Steels, Microscopic Structure 
 
 of, 4 
 
 , Special, 5 
 
 Steffen, 102 
 
 Stolzel, 78 
 
 Stoveine, 89 
 
 Strange, 64 
 
 Strontium Hydroxide, 82 
 
 Salts, 83 
 
 Strychnine, 88 
 
 Suchsland, 117 
 
 Sugar, Beet, 101 
 
 Sugar, Cane, 100 
 
 Sulphide Ores, Concentration 
 
 of, 7 
 Sulphur, Recovery of, from 
 
 Alkali Waste, 29 
 
 , Chloride, 84 
 
 L 2 
 
150 
 
 WHAT INDUSTRY OWES 
 
 Sulphuric Acid, 22 
 
 , Fuming, 26 
 
 , Impurities in, 87 
 
 , Removal of 
 
 Arsenic from, 27 
 Superphosphate of Lime, 96 
 Swan, 62 
 Swartz, 45 
 
 TALBOTYPE Process, 91 
 Tar, Distillation of, 36 
 
 Fractions, 38 
 
 Tartaric Acid, 80 
 
 Tavener, 20 
 
 Tawing, 61 
 
 Tennant, 20 
 
 Tetranitroaniline, 47 
 
 Thermite Process, 17, 19 
 
 Thomas and Gilchrist, 3 
 
 Thorium, 17 
 
 Thorpe, 79 
 
 Tilden, 64 
 
 Tin Ore, Concentration of, 
 
 Salts, 84 
 
 T.N.T., 45 
 Tobacco, 115 
 Toluene, 39 
 Tolypyrene, 89 
 Trimethylamine, 81, 103 
 Trinitrotoluene, 45 
 Tungsten, 16 
 Tyrian Purple, 41 
 
 UNVERDORBEN, 44 
 
 VALENTINE, 23 
 Van Helmont, 122 
 VanMarum, 129 
 Vanadium, 19 
 Vaseline, 54 
 
 Vauquelin, 17 
 Vegetable Tanning, 61 
 Vergara, 96 
 Veronal, 89 
 Vieille, 46 
 Vohl, 130 
 Vulcanising, 63 
 
 WASHING Soda, 28 
 Water, for Brewing, 1 05 
 
 Gas, 34 
 
 Glass, 83 
 
 , Softening of, 6 
 
 Watson, 35 
 
 Watt, 119 
 
 Waxes, 53, 57 
 
 Wedgwood, 90 
 
 Weldon, 31 
 
 Weldon Process, 131 
 
 Welsbach, 19 
 
 Welter, 47 
 
 West-Knight and Gall, 39 
 
 Whiskey, 113 
 
 Williams, 63 
 
 Willson, 131 
 
 Wines, 111 
 
 Winsor, 36 
 
 Wohler, 15, 17, 130 
 
 Wollaston, 20 
 
 Wood, 9 
 
 , Mechanical, 50 
 
 Pulp, 51 
 
 , Chemical, 50 
 
 Spirit, 110 
 
 Wort, 105 
 
 YOUNG, 55 
 
 ZINC Chloride, 83 
 Zirconia, 69 
 
 Printed by GEORGB RKVEIBS, LD., Greystoke Place, Fetter Lane, E.G. 
 
STAMPED BELOW 
 
 AN INITIAL FINE OF 25 CENTS 
 
 WILL BE ASSESSED FOR FAILURE TO RETURM 
 THIS BOOK ON THE DATE DUE. THE PENALTY 
 WILL INCREASE TO SO CENTS ON THE FOURTH 
 DAY AND TO $1.OO ON THE SEVENTH DA\ 
 OVERDUE. 
 
 warm 
 
 
 MAY 17 1937 
 
 
 
 
 " 
 
 
 25Apr'58BB 
 
 
 PEC'O ID 
 
 
 APR 1 1 1958 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 LD 2 1-1 00m- 8 
 
/ 
 
 / 
 
 YB 15476 
 
 387485 
 
 -T~ 
 UNIVERSITY OF CALIFORNIA LIBRARY