IN MEMORIAM 
 FLOR1AN CAJOR1 
 
 . 
 

 
 

 

 NEW THEORY 
 
 i 
 
 jf 
 '* TERRESTRIAL MAGNETISM. 
 
 (READ BEFOEE THE NEW- YORK LYCEUM OP NATURAL HISTORY.) 
 
 BY SAMUEL L. METCALF, M. D., 
 
 MEMBER OF THE NEW- YORK LYCEUM OF NATDRAL HISTORf- 
 
 
 " Omnes artes, quae ad humanitatem pertinent, habent quoddam commune 
 vinculum, et quasi cognatione quadam inter se continenter. "CICERO. 
 
 
 NEW YORK* 
 G. & C. & H. CARVILL 
 
 M DOCC XXXIII 
 
 

 Entered according to the Act of Congress, in the year 1833, by 
 
 SAMUEL L. METCALF, M. D., 
 
 in the Clerk's office of the District Court of the United States, for the Southern District 
 of New York. 
 
 
 SLEIGHT & VAN NORDEN, PRINT. 
 
 

 PREFACE. 
 
 No subject, perhaps, has more engrossed the at- 
 tention of philosophers, for the last two centuries, 
 than that of magnetic polarity. The cause of this 
 interesting phenomenon has, hitherto, evaded their 
 researches and baffled their ingenuity, until many 
 have abandoned the problem in despair, as an in- 
 scrutable mystery. Such despondency is inconsist- 
 ent with the progress of knowledge, and the spirit 
 of genuine philosophy. Had such men as Colum- 
 bus, Watt, and Fulton, been discouraged by the 
 narrow and sceptical views of those who could not 
 comprehend their reasoning, the advancement of 
 civilization would probably have been retarded 
 for centuries. Had Galileo, Newton, and other 
 exalted spirits, been deterred from their inquiries, 
 by the scoffs of their bigoted contemporaries, we 
 might still have been ignorant of the laws of gravi- 
 tation, and frightened, like savages, by the appear- 
 
 M3048G5 
 
ir PREFACE. 
 
 ance of every new comet, that approached the 
 orbit of our planet. 
 
 We cannot assign limits to the scope of the hu- 
 man mind in discovering the causes and relations 
 of things, when fully exerting its native freedom, 
 unfettered by the trammels of prejudice and the 
 routine of authority. It is by many persons con- 
 sidered presumptuous and disrespectful to question 
 the opinions of men, whose discoveries in science 
 have placed them high on the rolls of fame above 
 their contemporaries. Such a spirit is detrimental 
 to the progress of true knowledge. There should 
 be no standards of infallibility in science, but de- 
 monstrated truths. 
 
 We have been created with an unquenchable 
 desire to penetrate the veil with which Nature 
 conceals her mysterious operations: nor was it 
 intended that this desire should be disappointed. 
 With patient thought and persevering application, 
 it is impossible to limit the results which may flow 
 from the discovery of a single truth : for it is the 
 essential nature of truth to impart a divine illumi- 
 nation to the soul, by which it is strengthened and 
 prepared for still higher attainments. A brilliant 
 train of new ideas spring up from every quarter, 
 and the labor of years is accomplished in as many 
 
PREFACE. 
 
 months. Like the sun, it sheds light and beauty 
 over every object which it touches, irradiating the 
 path of future research. 
 
 The most important acquisition ever made to the 
 stock of human knowledge, was the discovery of 
 the directive power of the magnetic needle. Du- 
 ring the most enlightened periods of Greece and 
 Rome, commerce was restricted to a coasting navi- 
 gation. With no other guide than the stars, it was 
 impossible to explore distant regions, across wide 
 and trackless seas ; but since the discovery that a 
 piece of metal horizontally balanced, is constantly 
 directed to certain points in the polar regions, the 
 nations of the earth have become one great family 
 civilization and Christianity have been carried to 
 the most distant islands of the ocean ; and man 
 has extended his dominion over the whole habita- 
 ble globe. 
 
 

 
 . o 9rno!>^ 
 
 icftf 
 I' "fcr'-i 
 
A NEW THEORY 
 
 TERRESTRIAL MAGNETISM 
 
 PAR T I. 
 
 1. THE principal difficulties which have attended all inqui- 
 ries in relation to Magnetism, have arisen from our vague and 
 imperfect knowledge of the cause of attractions generally. 
 Simple as it really is, we have never had a satisfactory solu- 
 tion of the cause of capillary and cohesive attraction. The 
 most brilliant and original discovery of Sir Humphrey Davy, 
 was the supposed cause of chemical attraction, which he re- 
 ferred to the agency of opposite electricities in different ele- 
 ments. It must be acknowledged at the same time, that his 
 definition of electricity is vague and obscure, if not entirely 
 erroneous. He says, that " electricity appears to result from 
 the general powers or agencies of matter." He also denies 
 the materiality of caloric. 
 
 2. It will be our first object in this Essay, to trace some of the 
 most striking analogies of caloric -and electricity to show that 
 they are radically the same subtle, imponderable, and all-per- 
 vading element ; and that its unequal distribution throughout 
 Nature, is the cause of all the various powers and attractions 
 of ponderable matter with which we are acquainted. 
 
8 A NEW THEORY OF 
 
 3. A complete history of caloric would embrace an account 
 of all the changes and transmutations perpetually going on 
 throughout matter. It is the grand instrument of the Al- 
 mighty by which He executes the laws of nature. It is calo- 
 ric that thunders in the Heavens, as the voice of Omnipotence ; 
 which raises mountains from the ocean, and piles them like 
 turrets in the sky. It expands in the deeps below, and the 
 earth trembles; rocks are melted, and pyramids of flame 
 ascend above the clouds. 
 
 4. But in all its operations, its general agency is conserva- 
 tive. It is the source of life and motion throughout creation. 
 Its entire absence would mark the reign of everlasting silence 
 and death. It preserves the ocean in a fluid state, and imper- 
 ceptilby raises its waters into the atmosphere, to be distributed 
 over the dry land. The atmosphere itself would be a motion- 
 less mass of inert and chaotic matter, were it not for caloric. 
 
 5. It seems to be a general law of this subtle element, that 
 it repels its own particles, and is attracted, though un- 
 equally, by all other matter, with an increased ratio as the 
 squares of the distance diminish. 
 
 6. From which it follows, that when caloric is withdrawn 
 from a body, that body has a stronger affinity for caloric, than 
 one which is filled with it ; and that two bodies charged with 
 caloric, one plus and the other minus, will attract each other 
 with a force proportioned to the different quantities of caloric 
 which they contain, and to the rapidity of its conduction from 
 one to the other. 
 
 7. An experiment, which I inadvertently made when a 
 child, strikingly illustrates this principle. On the morning of 
 "cold Friday," as it was called throughout the Western 
 
TERRESTRIAL MAGNETISM. 9 
 
 Country, I applied my tongue to a plate of cold iron, while 
 the mercury was about 15 below zero, when it adhered with 
 such force that the skin was removed on separating it. Cap- 
 tain Scoresby relates, that frequently such was the intensity 
 of cold in the Arctic seas, that the hands of the sailors ad- 
 hered fast to whatever metals they touched. 
 
 8. In all such cases the temperature of the living body is 
 from 115 to 140 degrees higher than that of the metals : in 
 other words, the living body is charged plus, while they are 
 minus ; and the attraction continues until the equilibrium is 
 restored, when it ceases. 
 
 9. The same attraction takes place when the hand is ap- 
 plied to metals heated greatly above the temperature of the 
 living body ; and for the same reason, one of the two bodies 
 being charged plus and the other minus, 
 
 10. When the temperature of metals is greatly reduced, 
 they become brittle, so that a slight blow will fracture them : 
 the same effect is produced on iron by hammering, which 
 presses out, and expels from it that portion of caloric, which is 
 necessary to its' cohesion and malleability. Hence it follows, 
 that a certain amount of caloric between the particles of matter 
 is requisite to maintain their cohesion ; but when the amount 
 of caloric is increased beyond a certain extent, it separates the 
 particles, and thus diminishes, or overcomes, the power of 
 cohesion. 
 
 11. A great variety of facts may be adduced to show, that 
 capillary attraction is owing to the operation of the same 
 law. For example ; if a piece of sugar be put into a glass 
 of water, a portion of the caloric of fluidity leaves the water, 
 enters among the particles of sugar, and diffuses itself equally 
 
10 A NEW THEORY OF 
 
 throughout tbe whole. During this absorption of caloric by 
 the sugar, the temperature of the resulting mixture is some- 
 what reduced, proving that, in relation to the water, the sugar 
 is minus or negative, and. the water is plus or positive. 
 
 12. If the piece of sugar be cut into a cylindrical form, of 
 one or two inches diameter and five or six inches long, and 
 one end of it only be inserted into a glass of water, the caloric 
 of the positive fluid being strongly attracted by the negative 
 sugar, pervades it rapidly throughout, until the equilibrium is 
 restored, when the entire mass is dissolved. 
 
 13. M. Lehot found by experiment, that under the same 
 pressure, water rises higher in vertical capillary tubes as its 
 temperature is elevated. (Bibl. Univers. Mars. 1820, p. 225.) 
 
 14. The phenomena of a burning candle illustrate the 
 agency of caloric in producing capillary attraction in a very 
 striking manner. The wick is ignited, the tallow rendered 
 fluid, and attracted by caloric so as to furnish a continual sup- 
 ply of combustible matter to the wick, which is decomposed 
 and expanded into flame or light. The force and rapidity of 
 capillary attraction, all other things being equal, are in 
 proportion to the amount of heat given out in the wick. 
 
 15. Capillary and cohesive attractions are only modified 
 effects of the same cause. It is the attraction of caloric for the 
 particles of water, that holds them together; that gives its 
 drops their globular form ; as it is the attraction of caloric 
 for porous solids, and capillary tubes, that raises the water 
 above its ordinary level. 
 
 16. The same reasoning applies to every solution of crystal- 
 lized salts, ice, <fcc. and to every case of capillary attraction'. 
 Though this principle has never been fully understood, it has 
 
TERRESTRIAL MAGNETISM. 11 
 
 long been applied for the production of artificial cold. The 
 solution of muriate of ammonia in water greatly reduces its 
 temperature ; and if five parts of muriate of ammonia and 
 five of nitre be dissolved together in sixteen parts of water, 
 the temperature of the mixture will be lowered forty degrees, 
 the negative salts attracting and absorbing the caloric of the 
 positive water. 
 
 17. Another proof that salts, &c., are dissolved by caloric is, 
 that they again become crystals on the abstraction of caloric, 
 or as the solution cools down. Moreover, the solvent power 
 of water is increased as its temperature is increased. Some 
 salts are soluble in alcohol, that are insoluble in water '; and 
 it is obvious, that the specific heat of alcohol exceeds that of 
 water, from the following experiment. We put half an ounce 
 of ice by weight, into an ounce of alcohol ; and the same 
 quantity in an ounce of water, at the same temperature, when 
 the ice in the alcohol dissolved in twenty-four minutes ; while 
 that in the water dissolved in twenty-eight minutes. In ten 
 minutes after the ice was put in each vessel, the temperature 
 fell to thirty-two degrees in the alcohol, and to forty-one 
 degrees in the water, showing that the ice abstracted caloric 
 from the alcohol faster than from the water. 
 
 18. The greater quantity of latent caloric in alcohol than in 
 
 water, explains why it evaporates at a lower temperature than 
 >>ot ; 
 
 water and why it is not congealed by cold. The greater 
 
 quantity of caloric between its particles, prevents their coher- 
 ing into a solid state, and carries them off in the form of 
 vapor, when in open vessels. For the same reason, gaseous 
 bodies cannot be congealed, except by great pressure, which 
 evolves an enormous quantity of heat. All bodies exist in a 
 
1? A NEW THEORY OF 
 
 solid, fluid, or gaseous state, according as they contain more 
 or less caloric. 
 
 19. Philosophers have generally attributed the coldness pro- 
 duced by solution, to a change of volume ; but this is mistak- 
 ing the effect for the cause. A portion of the sensible caloric 
 of fluidity leaves the water, enters among the particles of the 
 solid crystal, converts it into a liquid, and thus becomes latent, 
 which causes the coldness. 
 
 20. Solution is merely the diffusion of caloric among the 
 particles of bodies, in search of an equilibrium. The cause 
 'of all the motions of caloric is its repulsion of its own particles, 
 and attraction for other matter. 
 
 21. Philosophers have never explained to us why oxidation 
 or combustion, goes on more rapidly at a high than at a low 
 temperature. They say, that caloric expands the combustible 
 materials, produces a vacuum, and thus affords free access to 
 the atmospheric oxygen ; but this is not satisfactory. It is 
 extremely probable, that the attraction of caloric for oxygen is 
 the cause of its rapid combination with the combustible 
 materials. 
 
 22. The attraction of caloric for ponderable matter is not 
 limited to small spaces. In the great laboratory of nature, it 
 acts on a large scale, where.it is the cause of evaporation. Its 
 attraction for water causes it to enter into, and expand its par- 
 ticles, by which it is carried into the atmosphere, in the form 
 of vapor which is thus charged positively with caloric ; 
 while the attraction of the same caloric for bodies charged 
 negatively, draws the vapor towards them. Thus mountains 
 which are colder than the atmosphere at the same elevations, 
 and therefore negative, attract distant masses of vapor which 
 are positive, abstract their caloric, and so cause them to descend 
 
TERRESTRIAL MAGNETISM. 13 
 
 in showers of rain, snow, and hail. It was observed long ago 
 by Dr. Franklin, that masses of vapor in different states of 
 electricity, attracted each other far beyond what he called the 
 striking distance. 
 
 23. It has probably been remarked by every person of 
 observation, that light masses of vapor from the ocean, on 
 approaching a mass of colder vapor from the northern points 
 of the compass, approximate each other with accelerated velo- 
 city, when the colder current of vapor attracts caloric from the 
 warmer ; and it is condensed into a hazy mist or cloud. 
 
 24. This is the rationale of all aerial condensations. When a 
 cloud is once formed, having parted with a portion of its calo- 
 ric, it is minus in relation to all uncondensed or transparent 
 vapor, which is plus. So that it becomes a centre of attrac- 
 tion, drawing to it successive masses of vapor, and abstracting 
 their caloric, by which a perpetual condensation or nimbifica- 
 tion is kept up, until an equilibrium is- restored.* 
 
 25. So decided is the attraction of caloric for ponderable 
 matter, and its repulsion of its own particles, that it passes with 
 greatest facility through the densest bodies, which are therefore 
 called conductors but with difficulty through those which are 
 light, such as gases, furs, silks, woolens, resins, &c., whose 
 pores are filled with caloric. 
 
 * After finishing- this essay, we witnessed on Sunday evening, June 2, 1833, the 
 most beautiful display of aerial condensations, that we remember ever to have 
 seen. The wind was brisk from the south, and brought from the ocean successive 
 masses of semi-transparent vapor of a red brassy hue, which allowed the rays of 
 the setting sun to pass partially through them, until as they advanced over the 
 city, vivid streaks of lightning- darted from them, when they were suddenly con- 
 densed into black clouds, which entirely intercepted the solar rays, and were 
 attended by rapid precipitations of rain. The showers intermitted and increased 
 several times in the course of half an hour, between the successive flashes of light- 
 ningand during the intermissions, the atmospheric vapor assumed the same 
 brassy color as at first. It will be seen presently, that these remarkable conden- 
 sations, resulted 1 simply from the giving out in the form of lightning, that portion 
 of caloric which is necessary to hold water in a state of vapor. 
 
14 A NEW THEORY OF 
 
 26. In tracing the relations of caloric and electricity, it be- 
 comes necessary to examine the source from which they are 
 derived, as well as the effects which they produce on common 
 matter. What then is the agent by which water is converted 
 into vapor and raised into the atmosphere ? Is it caloric or 
 electricity ? Almost all philosophers agree in the answer to 
 this question. 
 
 y, 27. It would seem obvious to the most superficial observer. 
 
 that caloric is the cause of evaporation, inasmuch as the great- 
 est amount of evaporation takes place in regions which receive 
 most of the sun's heat. We may form some idea of the vast 
 amount of caloric contained in atmospheric vapor, when we 
 reflect, that a pound of vapor will raise the temperature of a 
 pound of water nearly 1000 degrees* that its bulk is increased 
 about 1800 times in passing from a state of water to that of 
 vapor, and that all the rivers of the earth are supplied by its 
 precipitation. 
 
 28. What then becomes of all the caloric which must be 
 given out during the condensation of this vapor ? We know 
 that thunder and lightning are most abundant in the tropical 
 regions, and during hot, sultry weather in the middle latitudes. 
 Hence we infer, that the caloric of vapor, when greatly accu- 
 mulated^ is given out rapidly, in the form of electricity, on 
 approaching a colder mass of vapor, which is negatively 
 charged with caloric. 
 
 29. Does it not involve a striking contradiction to say, that 
 vapor is raised into the atmosphere by caloric, and that it is 
 condensed by the evolution of another distinct fluid, called 
 electricity ? If so, whence originated the electricity ? Are we 
 
 * Dr. Hare says, that there is twice the quantity of caloric " given out during 
 a snow storm, that would be given out by an equal quantity of re,d hot powdered 
 glass." 
 
TERRESTRIAL MAGNETISM. 15 
 
 to suppose with Dr. Thomson, " that when two currents of 
 dry air are moving different ways, the friction of the two sur- 
 faces may evolve electricity?" Absurd as this hypothesis 
 may appear, it forcibly illustrates the difficulty of accounting 
 for its origin and existence, when considered as a distinct ele- 
 mentary fluid from caloric. 
 
 30. We are not authorized to predicate a primary distinc- 
 tion, until fully acquainted with all the different states and 
 affections of caloric, under different circumstances for exam- 
 ple, in its combinations with different substances, in a solid, 
 fluid, gaseous, or imponderable state as with the matter of 
 light its diffusi6n, concentration, compression, &c. 
 
 31. Moreover, we are not philosophically warranted in 
 assigning more causes than are sufficient to explain the phe- 
 nomena. Now the expansion of fluids by caloric explains 
 satisfactorily the process of evaporation ; and the passage of 
 the same caloric out of the vapor is sufficient to account for 
 its condensation : whether it pass out slowly and insensibly, 
 or with rapid and explosive violence. 
 
 32. We know that condensation and precipitation of ^apor, 
 often take place, when two currents of vapor of different 
 temperatures unite, without any visible display of electricity. 
 We also know that caloric is given out during all aerial con- 
 densations. It is a matter of common observation, that the 
 weather is more hot and sultry in summer during the forma- 
 tion of clouds, than when the air is clear ; and that in winter, 
 it becomes warmer during a fall of rain or snow, unless ac- 
 companied by a northern wind. 
 
 33. There is not a greater apparent difference between any 
 of the forms of caloric and electricity, than between the elec- 
 
16 A NEW THEORY OP 
 
 tricity in the atmosphere, and in an exhausted receiver. The 
 explosion of gun-powder, resembles an electric explosion much 
 more nearly, than it does the combustion of ordinary fuel. 
 We often see the heavens filled with sheets of flame, produced 
 by the evolution of caloric from atmospheric vapor. 
 
 34. The spark from steel resembles the electric spark, except 
 that it will not pass through conductors : perhaps, because the 
 ignited matter with which it is combined is less subtle. 
 
 35. In subtlety, the electric and galvanic sparks are equaled 
 only by the solar rays. What can be more different, than ca- 
 loric in its free, and in its latent state ? When we shall under- 
 stand more thoroughly how caloric assumes so many different 
 states and appearances, we may discover how it exhibits elec- 
 trical phenomena. 
 
 36. Before caloric combines with, aid expands water into 
 atmospheric vapor, it is universally acknowledged to be sensi- 
 ble heat ; after it enters into the water and converts it into 
 transparent invisible vapor, its state is changed ; and, when 
 greatly accumulated in this state, it exhibits electrical pheno- 
 mena. To say, however, that its elementary nature is changed, 
 would be as unphilosophical, as to contend, that the latent ca- 
 loric of water is specifically different in its nature from the 
 same caloric, when set at liberty by pouring water on calcined 
 lime ; or that it is distinct from the caloric which moves a 
 steam engine by its expansion ; or that the galvanic fluid is 
 distinct from the electricity of a Leyden jar, because it moves 
 with less velocity. But it is universally acknowledged that 
 galvanism and electricity are essentially the same fluid ; and 
 we shall show hereafter, that galvanism is developed by the 
 combustion of metals in acids, alkalies, or atmospheric air. 
 
TERRESTRIAL MAGNETISM. 17 
 
 37. Had philosophers attended more carefully to the great 
 changes which take place in the states of caloric, produced by 
 its various modes of combination with other matter in different 
 forms, they would probably have been led to discover more 
 clearly, if not the identity of caloric and electricity, at least 
 that they are inseparable, and that without caloric there 
 could be no electricity. 
 
 38. We know that a Leyden battery may be filled with the 
 electric fluid drawn from a living man ; and that a living man 
 may be charged with the electric fluid until it runs over, pro- 
 ducing palpable currents.* 
 
 39. Many experiments have been made by M. Pouillet and 
 M. Becquerel in France, since the publication of Sir Hum- 
 phrey Davy's Chemical Philosophy, to prove that chemical 
 affinities are owing to electrical attractions. 
 
 40. Becquerel obtained the following results : " When an 
 acid combines with an alkali, a current in one uniform direc- 
 tion is established. The acid furnishes the positive, and the 
 alkali the negative electricity. When nitro-muriatic acid acts 
 upon gold, the acid is positive and the gold negative. In ge- 
 neral, an acid, during its action on a metal, is either negative 
 or positive, according to its concentration or dilution." 
 
 41. "A mixture of a concentrated solution of an acid with a 
 dilute solution of the same acid, produces electrical effects ; the 
 concentrated acid liberates the positive, and the dilute acid the 
 negative electricities." 
 
 42. " If into a filtered solution of the nitrate of iron, two 
 leaves of platinum foil be immersed, these leaves at the same 
 time communicating with the two ends of a multiplying wire, 
 
 * It is this fluid united with organic matter which produces animal heat. 
 3 
 
18 A NEW THEORY OF 
 
 if one of the leaves be suffered to remain in the solution, and 
 the other ' I?e withdrawn, and again immersed, a current of 
 electricity is produced, and the leaf which is re-immersed will 
 always liberate the positive electricity." 
 
 43. In all the above experiments, what is the electricity de- 
 veloped, but the liberation of the latent caloric of the different 
 substances employed, as their states are changed 1 
 
 44. " We have been the more particular," says Dr. Green, 
 to whom we are indebted for the account of these experiments, 
 " because they appear to us to throw considerable light on the 
 mutual relations which subsist between chemical and electrical 
 attractions relations which seem to govern the union and 
 combination of all material substances." 
 
 45. M. Pouillet found by experiment, that electricity was 
 evolved by the combustion of charcoal ; and that whenever 
 two gaseous bodies unite with each other, or a gaseous with a 
 solid body, one of them gives out positive, and the other nega- 
 tive electricity. It is susceptible of demonstration, that all 
 elements in a gaseous state contain caloric in proportion to 
 their specific gravity. The most dense contain it minus ; 
 while the lightest contain it plus. ( Ann. de Chem. et Phys. 
 XXXV. 401., and Thomson on Caloric and Electricity, 
 p. 497.) In reality, it is difficult to imagine any other cause 
 of specific gravity than caloric. M. Pouillet also proved, that 
 during the combustion of hydrogen, ether, alcohol, wax, fat, 
 and many vegetable substances, a zone of air surrounding the 
 flame was electrified plus, while the interior of the flame was 
 electrified minus. His inference was, that during the combus- 
 tion, the atmospheric oxygen gives out positive electricity. 
 
TERRESTRIAL MAGNETISM. 19 
 
 while the carbon and hydrogen of the combustible bodies give 
 out negative electricity. 
 
 46. If M. Pouillet's experiments are to be relied on, electri- 
 city is evolved during every combustion which takes place ; 
 also during the respiration of all plants. So much for the 
 agency of caloric in producing chemical affinities. We hope 
 to resume this interesting- subject on another occasion, when 
 we shall have more leisure to pursue it. 
 
 47. One of the most decisive proofs that caloric and electri- Y 
 city are convertible into each other is, thajt during all conden- 
 sations of aerial vapor, whether into rain or snow, during 
 
 
 winter or summer, caloric is given out in very large quantities. 
 
 It is notorious among the vulgar, that the air is rendered hot 
 and sultry, during summer, before showers, which is owing to 
 the heat given out by the transparent vapor as it condenses 
 into clouds, as before stated; also, that the temperature is 
 greatly moderated by a fall of rain or snow during winter. 
 In the above examples we perceive,, that the same fluid, 
 which, when greatly accumulated in the atmosphere, and sud- 
 denly given out, causes lightning and thunder ; under ordi- 
 nary circumstances of condensation, is given out silently, 
 producing no other sensible effect, than to raise the tempe- 
 rature. 
 
 48. Dr. Franklin was greatly puzzled to account for the 
 origin of atmospheric electricity. At one time he supposed that 
 it was produced in the ocean, by the friction of salt and 
 water ; but afterwards, finding this hypothesis unsatisfactory, 
 because he ascertained that clouds were negatively electrified, 
 and that all bodies were more or less filled with electricity, he " 
 imagined that the electric stroke passed from the earth to the 
 
20 A NEW THEORY OF 
 
 clouds, and not from the clouds to the earth : an hypothesis 
 still less tenable than his former one. 
 
 49. Mr. Daniell closes his late excellent work on Meteor- 
 ology, by stating, " that the interesting subject of atmospheric 
 electricity has been almost totally neglected ;" and " that at 
 present, he had nothing to ofTer on this most important branch 
 of physical science." 
 
 50. Dr. Thomson says, "that the formation of vapor- 
 seems to be connected with electricity, though in what way 
 the vescicular form is induced by electricity we have no con- 
 ception." It is indeed very difficult, if not impossible, to con- 
 ceive how and whence the electricity originated, if it be not 
 caloric. He adds further, " the formation of rain is still in- 
 volved in impenetrable obscurity." 
 
 51. With due deference to the opinion of Dr. Thomson, 
 the rationale appears very simple, if we admit that caloric and 
 electricity are convertible into each other. Water is expanded 
 by heat into transparent vapor raised into the atmosphere, 
 where it remains suspended, until it approaches the vicinity of 
 a mountain, or a mass of vapor, at a lower temperature, when 
 the attraction of caloric for those bodies which contain less of 
 it, causes it to leave the transparent vapor, and it coalesces 
 into mist, clouds, rain, snow, or hail. If the difference of 
 temperature be great between the masses of meeting vapor, 
 the equilibrium is restored suddenly by a violent explosion, in 
 the form of the electric spark or lightning. During winter, 
 the difference of temperature between different masses of vapor 
 is usually small in the middle latitudes, so that the equilibrium 
 is restored gradually and without explosion. During spring, 
 and especially in April, when masses of warm and cold vapor 
 
TERRESTRIAL MAGNETISM. 21 
 
 frequently meet, light showers are precipitated, by the sudden 
 passage of caloric from one to the other still without much 
 thunder and lightning. 
 
 52. But in summer when the atmosphere is saturated with 
 transparent aqueous vapor, which is full of caloric, its approach 
 to a mountain or a mass of vapor charged minus, is attended 
 with rapid and sudden transitions of caloric from the plus to 
 the minus body, causing terrific explosions of thunder and 
 lightning. 
 
 53. A large body of vapor from the tropics resembles an im- 
 mense Leyden jar, charged with caloric or lightning. The 
 globe itself is but the grand laboratory of nature, which the 
 art of 'man has imitated on a Lilliputian scale. 
 
 
 
 " Neque aliud est natura quam ars quaedam mag-na." 
 
 LEIBNITZ. 
 
 54. Dr. Arnott has given substantially the following expla- 
 nation of rain, in the first volume of his work on Nat. Phil, 
 p. 348. The production of rain and snow, he attributes to 
 the elevation of watery vapor into the higher regions of the at- 
 mosphere, where, from the greater dilatation of the atmosphere, 
 it becomes colder, and thus condenses the atmospheric vapor. 
 He takes no account of the diminished quantity of caloric 
 in clouds already formed, and in mountains, high plains, 
 &c., which abstract caloric from invisible vapor, and cause it 
 to descend in rain. 
 
 55. It is notorious that when the wind blows steadily in 
 one direction, for some time, over a level country, very lit- 
 tle rain falls. In the great desert of Sahara, there is scarcely 
 any rain, because the vapor transported over it by the west 
 wind is still further rarified by the heat of the scorching sand, 
 
22 A NEW THEORY OF 
 
 where there are no mountains to condense it. For a similar 
 reason, we often have long droughts in the level parts of the 
 United States during summer. Owing to the great heat of 
 the atmosphere, the vapor brought from the Atlantic ocean 
 by southern and eastern breezes, is not condensed, but still 
 further expanded, until it meets with a current from the north- 
 ern points of the compass a descent of cold air from the 
 higher regions* or with mountains and highlands of a lower 
 temperature, when thunder gusts follow. 
 
 56. After a long drought, the first precipitations take place 
 over moist ground, river courses, &c. which are colder or ne- 
 gative, and therefore attract the electric fluid from the positive 
 atmospheric vapor. Hence it frequently occurs, that such 
 situations receive two or three showers, before the rain becomes 
 general. 
 
 57. When the aerial vapor is condensed into a cloud, by 
 giving out a portion of its caloric, it becomes negative in rela- 
 tion to the surrounding vapor, and attracts caloric from it ; 
 which also becomes negative, and acts on the neighboring 
 vapor in the same way, until it is successively condensed for 
 several hundred miles, and the rain becomes general. When 
 the equilibrium is restored, the storm ceases, and the sky 
 becomes serene. 
 
 58. Our equinoctial storms are produced by the meeting of 
 extensive masses of vapor, from opposite quarters, of different 
 
 * Dr. Thomson has asserted that air cannot descend without giving out its caloric 
 as it falls, which he thinks would prevent it from cooling the temperature of the 
 lower atmosphere. He seems not to have been aware, that the upper air may be 
 more condensed by cold than the lower air by pressure, in which case its descent 
 would be attended by a reduction of temperature, in proportion to the mass which 
 descends from above. The sea and the air over it are less heated, because the water 
 on its surface rises in the form of vapor, carrying off a great portion of its caloric. 
 
TERRESTRIAL MAGNETISM, 23 
 
 temperatures. The vast amount of condensation, caused by 
 the meeting of opposite currents, while the sun is passing the 
 line, occasions extensive vacuums a violent rush of elastic 
 vapor from different quarters is the consequence, constituting 
 whirlwinds, hurricanes, and tornadoes. 
 
 59. In the United States, the difference of temperature be- 
 tween northern and southern winds, is much greater than in 
 Europe, which has a maritime climate, and on the ocean ge- 
 nerally, where the temperature is more uniform ; for this rea- 
 son, we have more intense lightning than in Europe and 
 on the ocean, and not as M. Volney supposes, " because of 
 the greater dryness of our atmosphere." The most violent 
 thunder storms on the American continent occur in July and 
 August, when the air in the middle latitudes is greatly rare- 
 fied, so as to favor a descent of the cold upper current from 
 the equator. 
 
 60. Dr Franklin believed, that vapor was held in a state of 
 solution by electricity, but it is evident that caloric is the vapor- 
 izing agent all over the world. It would seem a waste of time 
 to say more in proof of the identity of caloric and atmospheric 
 electricity. There is no thunder and lightning in the polar 
 regions. 
 
 61. Before leaving this interesting subject, it may be proper 
 to take a cursory view of the agency of caloric in producing 
 atmospheric currents generally. 
 
 62. There are three great currents of the aerial ocean, by 
 which it is kept in perpetual circulation : one from the polar 
 regions towards the equator, which is an under current : another 
 from the equator to the poles ; which is an upper current : 
 arid a third, called the equatorial current, or trade wind; which 
 
24 A NEW THEORY OF 
 
 blows from east to west, around the globe, for about thirty 
 degrees on each side of the equator.* 
 
 63. There is another general wind which blows from west 
 to east, in the middle and higher latitudes ; in the northern 
 hemisphere about two thirds of the year : while in the southern 
 hemisphere, it is nearly as uniform as the trade wind, where 
 there is no land. 
 
 64. Dr. Hadley, and after him, Dr. Franklin, attributed 
 these currents to the following causes. " The air under the 
 equator and between the tropics, being constantly heated and 
 rarefied by the sun, rises : its place is supplied by air from the 
 higher and polar latitudes, which, coming from parts of the 
 earth, that had less motion, and not suddenly acquiring the 
 quicker motion of the equatorial earth, becomes an east wind 
 blowing westward ; the earth moving from west to east and 
 slipping under the air." Mr. Daniell has shown conclusively, 
 that, from the greater density of the .polar atmosphere than 
 the equatorial, its height is proportionally less : so that the air 
 rarefied between the tropics, and rising, must flow toward the 
 poles. Before it rose, it had acquired the greatest motion the 
 earth's rotation could give it : It retains some degree of this 
 motion, and descending in higher latitudes, where the earth's 
 
 * Our north east winds are often produced by a deflection of the polar current 
 on its passage to the equator, by the more rapid motion of the lower latitudes, 
 in a mode similar to the production of the trade wind. 
 
 Variable winds are caused by temporary and local rarefactions all atmo- 
 spheric currents, however, are governed by the same general laws. 
 
 In the United States, in India, and in southern China, the land becomes 
 greatly heated during summer, while the sun is on this side of the line, which 
 causes a predominance of wind from the ocean, which is then,cooler; but when 
 the sun leaves our hemisphere, as in winter, the prevalent wind is from the north- 
 ern points of the compass modified, however, in all cases by the revolution of 
 the earth on its axis, by the height and direction of mountains, and by local 
 rarefactions. The semi-annual periodic movements of the atmosphere, caused 
 by the alternate heating and cooling of the land and sea, have been styled mon- 
 soonsand by some writers, periodical trade winds. 
 
TERRESTRIAL MAGNETISM. 25 
 
 motion is less, becomes a westerly wind. (See Franklin 1 s 
 Works, vol. 3. p. 236. and Mr. Daniell on the Atmosphere.) 
 
 65. It was thus Dr. Franklin accounted for the coldness of our 
 north west winds, and of our summer gusts, which are gene- 
 rally from the same quarter. That this is the true mode of 
 accounting for our cold summer gusts, is obvious from the fol- 
 lowing considerations. The land being greatly heated, rare- 
 fies the atmosphere over it, until the superincumbent air sinks 
 down, and mixes with it. , 
 
 66. At the same time it communicates its tropical motion 
 from west to east ; condenses the vapor of the lower atmos- 
 phere by absorbing its caloric, and thus produces our western 
 thunder-gusts, which are often attended with hail, and almost 
 always with a great reduction of temperature. In this way 
 clouds are sometimes formed suddenly, the whole sky becom- 
 ing obscured by dense black vapor. It is a remarkable fact, 
 that thunderstorms almost always occur between mid-day and 
 sunset, when the air is most heated and rarefied, so as to favor 
 a descent of the upper current from the equator. 
 
 67. The difference between the temperature of the ocean 
 and atmosphere over it being small, there is little or no dew 
 at sea, and very little thunder and lightning. The unceasing 
 motion of its particles preserves a uniform temperature, being 
 only two or three degrees colder during night, than during 
 day : while on land the difference is often ten times as great. 
 
 68. Air considerably rarefied by heat, receives into it a much 
 greater quantity of vapor before it is saturated than cold air, be- 
 cause it affords much more room between its particles for the 
 expanded vapor to pass through it, and because it does not con- 
 dense the vapor, but allows it to accumulate in larger quantities 
 
26 A NEW THEORY OF 
 
 before precipitation. Hence, though there be more invisible 
 water in the atmosphere during summer than winter, there is 
 less visible vapor : more rain in summer, but more fog in winter. 
 In this latter state, the atmosphere is a better conductor of caloric 
 than during summer, which thus passes freely from place to 
 place, without being accumulated, and therefore without explo- 
 sion. This, together with the diminished quantity of caloric in 
 the atmosphere, is the reason there is no thunder and lightning 
 in the polar regions, nor in our own climate during winter. In 
 the production of dew and frost, the earth is first cooled down by 
 radiation, when it attracts caloric from the stratum of transpa- 
 rent atmospheric vapor immediately over it, by which it coa- 
 lesces into dew or frost, according to the temperature of the 
 surface. 
 
 69. When we examine the mode in which galvanic electricity 
 is produced, we discover a still more intimate relation to caloric 
 than in any of its other forms. We shall find that in every 
 case, it is produced by the combustion of metallic plates differ- 
 ently oxidizable, and that the energy of the pile is proportional 
 to the rapidity with which the intervening acid is decomposed. 
 The oxygen of the acid combines with the metal, and electri- 
 city is evolved, in the same way that caloric is given out 
 during common combustion. 
 
 70. The principal difference is, that in common combustion, 
 a great portion of the caloric evolved, is carried off in the 
 vapor of the combustible materials in the stale of flame, &c., 
 while in the combustion or oxidation of metals by the pile, the 
 caloric is not carried off, owing to the less evaporable nature 
 of the metals ; so that it is concentrated and conveyed by the 
 conducting wires to the extremities of the battery. We shall 
 
TERRESTRIAL MAGNETISM. 27 
 
 also find, that the energy of the battery is proportional to the 
 extent of the metallic surfaces, as well as to the decomposibility 
 of the fluid which supplies the oxygen. When the decompo- 
 sition of the fluid ceases, the pile loses its energy, and the 
 galvanic current is at an end. 
 
 71. We are informed by writers on galvanism, that a few 
 large plates disengage more of the galvanic fluid than a 
 great number of small plates; but that the intensity 
 of its action is in proportion to the number of plates. They 
 have not given any reason for this difference, which is pro- 
 bably owing to the fact, that the oxidation of large plates, 
 resembles more nearly the process of ordinary combustion, and 
 the calorific or electric currents are combined with a larger pro- 
 portion of metalic matter and hence cannot be conducted off 
 by the connecting wires with the same velocity that it is when 
 in a more subtle state. Caloric, electricity, and galvanism, 
 have hitherto constituted a separate and distinct triad of im- 
 ponderables, perfectly incomprehensible ; all the phenomena of 
 which are quite intelligible, if we refer them to the agency of 
 one grand, primary, universal element. Will any philosopher 
 contend, that during the oxidation of metals by a galvanic 
 pile, there are two distinct fluids disengaged, caloric and elec- 
 tricity ? or that during the evaporation of water, two distinct 
 imponderable fluids become latent in its vapor ? The idea is 
 absurd. 
 
 72. The earth may be considered as a huge galvanic pile, 
 and the various combinations and decompositions which mark 
 all its chemical changes, are effected by the agency of caloric 
 in some of its forms. 
 
 73. Thus we perceive, that the galvanic fluid is produced in 
 
26 A NEW THEORY OF 
 
 the same way .that caloric is produced, viz., by combustion, or 
 by the union of oxygen with combustibles. M. Pouillet 
 found, as we beforeobserved,that whenever two bodies united by 
 combustion, the supporter gave out positive, and the combus- 
 tible, negative electricity. 
 
 74. We know, that during every combination of oxygen 
 with combustible matter, caloric is given out. There can be 
 no doubt, that all earthquakes, volcanoes, and thermal waters, 
 owe their existence to the caloric given out in the lower parts 
 of the earth, in a mode similar to its evolution from a galvanic 
 pile. It is certainly given out during all oxidations of 
 the earths and metals and we know that oxidation is per- 
 petually going on throughout all matter, as far as we are ac- 
 quainted with it. In treating of atmospheric electricity, we 
 endeavored to show, that it resulted from the accumulation of 
 solar heat in aqueous vapor, and from its rapid passage out of 
 this vapor into bodies charged negatively with caloric from 
 which it follows, that the sun is the great fountain of atmo- 
 spheric electricity. We have seen, that caloric is universally 
 diffused throughout terrestrial matter in a latent state. It can 
 be disengaged from all bodies by pressure, friction, and by 
 chemical decomposition : electricity is produced in the same 
 way. 
 
 75. Caloric in its latent state, does not differ more from its 
 active state, than does sulphuric acid in its separate state, from 
 that of its combination with soda or magnesia. Nor does it 
 differ more from electricity, than does electricity from itself, in 
 an exhausted receiver, and under the pressure of the atmo- 
 sphere. 
 
 76. Dr. Franklin denominated the fusion of metals by 
 
TERRESTRIAL MAGNETISM. 20 
 
 electricity, a cold fusion. He adds, " I do not mean fusion by 
 the force of cold, but a fusion without heat, because, it ex- 
 pands and separates their particles instantaneously, without 
 producing combustion." (See his Works^ vol. 3. p. 51.) But 
 we know, that if an electric or galvanic current is continued 
 through the metals, combustion occurs with sensible heat 
 and if retarded or obstructed in its passage, it produces an ex- 
 plosion. If it be asked why the electric spark does not pro- 
 duce the sensation of heat, we answer, because of its velocity, 
 and the subtlety of the combustible matter with which it is 
 combined. The hand may be held in a shower of sparks 
 produced by the friction of steel with emery, without a sensa- 
 tion of heat, for the same reason, unless the sparks be very 
 large. 
 
 77. Dr Hare acknowledges himself obliged to believe, " that 
 caloric and electricity are closely combined," by what he calls 
 " the reciprocal attraction of imponderables." (See his Con- 
 troversy with Prof. tSilliman on the Nature of Caloric 
 developed by his Calorimotor.) % 
 
 78. With sentiments of great respect for the acknowledged 
 talents of so distinguished a chemist as Dr. Hare, we h'ave 
 not been able to find the slightest evidence, that any such affi- 
 nity exists between caloric and electricity, admitting them to 
 be distinct elementary fluids. On the contrary, I found by 
 experiment, that the end of a metallic rod at a white heat is 
 a bad conductor of electricity ; which is probably the reason 
 why the boilers of steam-boats are never struck by lightning 
 when heated. 
 
 79. Caloric, which is imponderable, has an undoubted at- 
 traction for ponderable matter, which is the reason it cannot 
 
30 A NEW THEORY OF 
 
 be kept in a separate state, unless insulated by non-conduc- 
 tors, and then only for a limited time ; whether in the form of 
 domestic heat, galvanic, or common electric heat, but univer- 
 sally seeks a latent state, by entering into other matter, and 
 thus becoming a constituent portion of it. 
 
 80. The attraction of oxygen for combustibles, which is 
 owing to their being in different states of caloric, causes a per- 
 petual combustion throughout nature. Perhaps there is no 
 such thing as total quiescence in matter. Hence bituminous 
 coal is continually changing by oxidation, and passing into a 
 state of anthracite or hard coal. Hence also the accumulation 
 of caloric, given out by combustion in the bosom of the earth, 
 which is restrained for centuries by superincumbent pressure, 
 until its elastic force overcomes all resistance, and raises 
 mountains, or bursts forth into volcanoes. 
 
 81. It is this tendency of oxygen to combine with other ele- 
 ments which causes the various decompositions of organic 
 matter. Its combination with the nitrogen of animal matter 
 in a state of decay, supplies the waste occasioned by the con- 
 sumption of common air in the respiration of animals and 
 plants. A portion of atmospheric oxygen unites with the hy- 
 drogen of animal matter, and produces water; so that every 
 source of putrefaction, is, to a certain extent, a perpetual spring 
 of regeneration and compensation. In the decomposition of 
 vegetable matter, we perceive the same beneficial results. 
 The oxygen of the air unites with the carbon of vegetable 
 matter, making carbonic acid gas, the appropriate food of liv- 
 ing vegetation. And so on through all the endless ramifica- 
 tions of nature, we perceive, that death is only a transmuta- 
 

 TERRESTRIAL MAGNETISM. 31 
 
 tion of matter, by which it is prepared for entering into new 
 forms of life and beauty.* 
 
 82. Decomposition is merely the separation of the element- 
 ary particles of matter by caloric, by which they are prepared 
 for entering into new combinations. How beautiful are the 
 ordinances of nature ! It would be interesting, if this were 
 the proper place, to show how far the attraction of vitality 
 resists chemical decomposition. 
 
 83. We have seen that caloric is not only the cause of chemi- 
 cal and cohesive attraction, but, that when accumulated, it is the 
 agent by which the molecular attractions of matter are dissolved. 
 In short, that it is the cause of all the changes which take 
 place throughout the globe. If rocks and salts are dissolved 
 in water, it is caloric which effects it. If rocks and hills are 
 carried down by running water into the plains and seas, calo- 
 ric is the cause of fluidity. The purification of all metals is 
 effected by caloric, which vaporizes and carries off their drossy 
 combinations. 
 
 84. We cannot pass over in silence, what we consider a 
 fundamental error on electricity, which has been embraced 
 by many modern writers in France and England. We 
 allude to the doctrine of two distinct electricities a doctrine 
 which has no foundation in truth which is contrary to the 
 simplieity that characterizes all the operations of nature and 
 which will not bear the test of philosophical analysis. It has 
 arisen from the fact, that vitreous substances are electrified 
 positively, while resinous substances are negative. 
 
 85. It is stated by different authors, that whenever a body is 
 charged with positive electricity, it tends to produce nega- 
 
 * This is what Pythagoras must have intended to inculcate in his Metempsy- 
 chosis. 
 
3 A NEW THEORY OP 
 
 live electricity, in all the bodies in its vicinity. (Lib. of U. 
 Knowledge, Article Electricity.) T his fact alone is sufficient 
 to refute the doctrine of two distinct fluids. How is it possi- 
 ble to conceive that a body charged with vitreous or positive 
 electricity, can communicate electricity of another species to a 
 body in its vicinity ? The difference is only in degree. The 
 communicating body being charged plus, imparts a portion of 
 its electricity to bodies near it, which become minus or nega- 
 tive. Every attempt to improve this simple and beautiful 
 theory of our countryman, Dr. Franklin, has only rendered the 
 subjectof electricity more complicated and obscure. A distinction 
 has been inferred from the difference of form and color of elec- 
 tric sparks produced by positive and negative electricity. As 
 well might we say that there are different species of caloric, 
 modifying the numerous colors of flame in ordinary combus- 
 tion. The color and form of the electric spark depends on 
 its size, and on the nature of the conductor through which it 
 
 86. It is stated, that if a plate of glass with a polished sur- 
 face be rubbed against one which is roughened, the former 
 always acquires the vitreous, and the latter the resinous elec- 
 tricity. (See Lib. U. K.) What better proof could be re- 
 quired, that in the above cases there are not two distinct elec- 
 tricities developed ; but that in one case it is plus, while in 
 the other it is minus. 
 
 87. It is difficult to conceive how Sir Humphrey Davy mis- 
 took the attraction between electricity and ponderable matter, 
 for an attraction between two electricities. When the ponde- 
 rable elements attract each other, he supposed that it was 
 owing to the attraction of positive for negative electricity. 
 
TERRESTRIAL MAGNETISM. 33 
 
 88. Now it is demonstrable, that when two bodies are 
 charged with the same electricity, one plus and the other mi- 
 nus, whether positive or negative, they attract each other 
 so that it is owing to the attraction of electricity for ponderable 
 matter, and its repulsion of its own particles, that causes 
 bodies which contain different quantities of electricity to com- 
 bine. Will it be said that the attraction of my hand for frozen 
 mercury is owing to its being filled with positive electricity, 
 and the mercury with a different, species of electricity, which 
 is called resinous ? and that it is the attraction of the two elec- 
 tricities for each other which causes the effect ? The idea is 
 preposterous. The hand is plus and the mercury is minus 
 and caloric is attracted from the plus to the minus body. 
 The above mistake has been a perpetual barrier to a clear 
 understanding of electrical attraction. 
 
 89. To enumerate all the effects of caloric would be to give 
 a history of universal nature. 
 
 90. It is conceded by nearly all those who have investigated 
 the nature of latent caloric, that it is universally diffused 
 throughout matter ; that the form and bulk of all bodies are 
 owing to the existence of caloric between their molecules. 
 For example, the specific gravity of all the gases is the inverse 
 measure of their specific caloric. That of hydrogen being least, 
 it contains the largest amount of specific heat. The specific 
 gravity of aqueous vapor, is less than that of atmospheric air, 
 but its specific heat is greater ; and so of all the gases : their 
 specific heat is inversely as their specific gravities. 
 
 91. It has been rendered extremely probable by the experi- 
 ments of Du Long and Petit, "that the specific caloric of 
 every body is inversely as its atomic weight." 
 
34 A NEW THEORY OF 
 
 92. From the above facts and observations, it follows, that 
 one of the principal functions of caloric is to give volume to 
 bodies by keeping their particles asunder ; that in reality all 
 light bodies are composed chiefly of caloric in a latent state. 
 Hence, the reason why gases and all light spongy substances 
 are bad conductors of caloric, which repels its own particles ; 
 while the densest bodies, such as gold, platinum, and silver, 
 are good conductors.* It would be interesting to trace the few 
 exceptions to this general law : for example, why melted 
 resins are better conductors than in the solid state, together 
 with a few others. 
 
 93. The small specific gravity of wool, furs, silk, sponge, 
 cork, &c., has been attributed by Dr. Thomson to the diffu- 
 sion of air through their interstices ; but we have shown that 
 the bulk of atmospheric air, and of all other bodies, is owing 
 to caloric, which is easily demonstrated by condensing them 
 by pressure, when light and heat are copiously given out, and 
 in many cases accompanied by electrical phenomena. ^ Ji 
 
 94. The identity of caloric and electricity is strikingly exhi- 
 bited by their analogous effects on ponderable matter. Elec- 
 tricity, as well as caloric, expands atmospheric air, water, &c. 
 Dr. Franklin filled a small glass tube with water, and sent a 
 charge of electricity through it, by which it was shattered to 
 pieces, thrown all over the room, and the water evaporated. 
 The same effect is still more obvious with oil. Electricity 
 inflames ether, alcohol, and gunpowder, renders wine red-hot, 
 singes the hair of animals, sets houses, trees, &c., on fire. 
 
 * That it is the expansive power of caloric which raises water into the amo- 
 sphere, and not its affinity for air, is evident from the experiments of Mr. Dalton, 
 who proved that evaporation goes on much more rapidly in an exhausted receiver 
 than under common atmospheric pressure. 
 
TERRESTRIAL MAGNETISM. 35 
 
 95. The calorific effect of lightning is so intense, that, when 
 it passes down a metallic chain, instead of a rod, it often fuses 
 the chain so as to part it, doubtless owing to the retardation of 
 the electric fluid, by the air between the links, which is a bad 
 conductor. The damage which is usually produced on 
 houses, ships, trees, <fcc., by lightning, is owing to their being 
 imperfect conductors ; and consequently arresting or retarding 
 the fluid, until it tears, burns, and fuses them. Caloric repels 
 its own particles, and is attracted by ponderable matter ; the 
 same is true of electricity. They are also both conducted by 
 the same materials. Caloric and electricity are both attracted 
 by points. Caloric enters slowly into a smooth metallic body, 
 but rapidly into one which presents a great many points. 
 They are both produced by friction and by pressure. 
 
 96. That caloric, or electricity, is greatly concentrated on 
 quitting a mass of vapor in the form of lightning, is proved 
 by the fact, that a single spark or streak causes a general pre- 
 cipitation of rain ; from which we are authorized to infer, that 
 its force and velocity are owing to its condensation. When 
 greatly compressed in the form of steam, the velocity of its 
 explosion is instantaneous. 
 
 97. Flannel, worn next the skin, apquires electrical proper- 
 ties, and gives out sparks freely on rubbing it. Signor Ma- 
 tracci, of Forli, found by experiment, that when glass plates 
 were exposed to the solar rays, they became electric if no 
 clouds intervened. If a Leyden jar could be charged with 
 electricity by the solar rays, with a prism, or a burning glass, 
 the experiment would be still more conclusive. 
 
 98. The rapid motion of electricity has been considered as 
 an argument against its identity with caloric : but we have 
 
 /- 
 
 *vt'f -**- '~L--C 
 
 j-^3- **, 
 
 ^ 4 A./a^Ut.- ' s 
 
36 A NEW THEORY OF 
 
 proved that the rapidity of its motion, is owing to its accumu- 
 lation. When caloric is greatly accumulated in iron, as when 
 it is brought to a white heat, it is radiated with great velocity, 
 carrying off with it portions of the metal in a state of incan- 
 descence, or sparks, with a rapidity resembling the electric 
 spark. The spark from flint and steel is produced by the 
 percussion of hard bodies, and moves with great rapidity. 
 
 99. Electricity can be drawn from a prime conductor 
 gradually, by means of a sharp metallic point, without pro- 
 ducing a spark, when it becomes a constant current while the 
 cylinder is turning : and if directed on the forehead it pro- 
 duces the sensation of a pleasant breeze. If the human body 
 be insulated while the current is passing into it from the 
 prime conductor, it is very soon saturated, when the fluid runs 
 over the hair stands erect, until the body is brought near to 
 a conductor, when it passes off, and the equilibrium is restored. 
 
 100. It cannot be contended, that the velocity of the electric 
 fluid is greater than that of the solar rays. Caloric, like elec- 
 tricity, moves with a velocity proportioned to its intensity at 
 its source. Caloric and electricity, in all their forms, produce 
 the same light. The combustion of charcoal by a current of 
 galvanic electricity, causes the most vivid light in nature, 
 except that of the solar beams, When decomposed with a 
 prism, they present the same elements. 
 
 101. We have been thus particular in elucidating the 
 subject of electricity, in connection with caloric, from a 
 deep conviction of its importance and because we believe 
 that it is not rightly understood. It is contrary to that sim- 
 plicity which characterizes all the operations of nature, to 
 make a primary distinction between them : consequently it is 
 
TERRESTRIAL MAGNETISM. 7 
 
 unphilosophical to consider them as separate branches of pneu- 
 matology. Though we do not pretend to understand how it 
 is, that caloric in all cases exhibits electrical phenomena, we 
 have proved, that, independent of caloric, electricity has no 
 existence. 
 
 102. We have no evidence that either caloric or electricity is 
 ever visible, unless when combined with other matter in a 
 state of expansion. There is no matter which does not be- 
 come luminous when greatly expanded by this subtle element. 
 The light of a candle is produced by the expansion of its com- 
 bustible materials by caloric; from which it follows, that 
 light is composed of ponderable matter in a state of extreme 
 diffusion. 
 
 103. Dr. Fusinieri found by experiment, that the electric 
 spark drawn from metallic conductors, carries off with it a 
 portion of the metal, in a state of fusion, or of incandescent 
 molecules, whatever be the nature of the metal. Are we not 
 authorized to infer from the above facts, that solar light is 
 composed of the matter of the sun, so exceedingly expanded 
 by caloric, as to become phosphorescent and imponderable ? 
 The expansion of solid matter into light by caloric, is, perhaps, 
 the nearest approach to the ultimate division of matter, that 
 we can conceive. 
 
 104. In so large a body of matter as the sun, is there not 
 caloric enough constantly evolved, to bear off a portion of its 
 matter through all the illimitable fields of space? It is not a 
 little surprising, that the production of light by common com- 
 bustion, did not long ago lead philosophers to this conclusion. 
 They generally agree, that in light, caloric is combined with 
 
38 A NEW THEORY OF 
 
 some other material. In the case of a burning candle, what 
 is it, but the diffusion of its combustible matter !* 
 
 105. What shall we say of those theorists, who deny the 
 materiality of both light and heat ? who reject the evidence of 
 their senses : and who will not believe in the existence of any 
 thing which cannot be weighed with our imperfect balances, like 
 a loaf of bread. They know that caloric increases the volume of 
 matter : they also know that light is decomposable, and that 
 it produces chemical changes on other matter ; yet they main- 
 tain, that they are merely the result of motion among the 
 particles of bodies. If asked what causes this motion among 
 the atoms of ponderable matter, they are silent. If they are 
 referred to the elastic power of caloric in a steam engine, they 
 are equally at a loss. Admitting that caloric is the effect of 
 motion among the particles of water in the boiler, what causes 
 the motion ? It is something which produces palpable and 
 visible expansion ; therefore, must be matter. 
 
 106. Dr. Young, and Mr. Herschel, jun., tell us, that 
 light consists of the periodic movements of an elastic medium 
 which pervades all space regularly recurring at equal inter- 
 vals, no less than five hundred millions of millions of times in 
 a single second. That it is by such movements communi- 
 cated to the nerves of our eyes, that we see : nay, more, that 
 it is the frequency of their recurrence which affects us with 
 the sense of the diversity of colors ; that, for instance, in ac- 
 quiring the sensation of redness, our eyes are affected four 
 hundred and eighty-two millions of millions of times ; of yel- 
 
 * It has been ascertained by the experiments of M. M. Nobili and Melloni, 
 that phosphorescent matter is always accompanied by caloric, though in small pro- 
 portion. (See Annales de Chim. et de Phys.for October, 1831.) 
 
TERRESTRIAL MAGNETISM. 39 
 
 lowness, five hundred and forty millions of millions of times ; 
 and of violet, seven hundred and seven millions of millions of 
 times per second.* 
 
 107. The question naturally arises, what is the elastic me- 
 dium to which these distinguished philosophers refer, if it be 
 not caloric? and what is the cause of the rapid periodic 
 movements, to which they attribute the sensation of different 
 colors, admitting that such periodic movements do exist ? We 
 doubt Very much whether the above theory will stand the test 
 of rigid analysis. It reminds us of Mr. Herschel's definition 
 of abstract science, contained in the second chapter of his really 
 beautiful Discourse on Natural Philosophy. He says, " that 
 abstract science is independent of a state of nature of crea- 
 tion of every thing in short, except memory, thought, and 
 reason." We confess ourselves unable to comprehend the 
 meaning of such definitions. 
 
 108. Nothing is more surprising than that such men as 
 Count Rumford and Sir Humphrey Davy, should have 
 doubted the material and independent existence of caloric. 
 Sir Humphrey Davy supposed, that caloric was often pro- 
 duced by the combination of vitreous and resinous electricity 
 in wlrlch opinion he has been followed by Winter! and 
 Oerstedt. 
 
 109. That the reader may fully understand the views of 
 Sir Humphrey Davy in regard to the nature of caloric, we 
 shall present the following quotation from his Chemical Phi- 
 losophy, page 52 ; observing at the same time, that we think 
 
 * See a Discourse on the Study of Natural Philosophy, by J. F. W. Herschel, 
 Esq., F.R.S., and Young'a Lectures on Natural Philosophy, Vol. 2, p. 627. 
 
40 A NEW THEORY OF 
 
 it the most inconclusive reasoning contained in his valuable 
 work, and altogether unworthy of so great a man. 
 
 110. "When the temperature of bodies is raised by friction, 
 there seems to be no diminution of their capacities, using the 
 word in its common sense ; and in many chemical changes 
 connected with an increase of temperature, there appears to be 
 likewise an increase of capacity. A piece of iron made red hot 
 by hammering, cannot be strongly heated a second time by the 
 same means, unless it has been previously introduced into a 
 fire. This fact has been explained by supposing that the fluid 
 of heat has been pressed out of it by the percussion, which 
 is recovered in the fire ; but this is a very rude mechanical idea. 
 The arrangements of its parts are altered by hammering in 
 this way, and it is rendered brittle. By a moderate degree of 
 friction, as it would appear from Rumford's experiments, the 
 same piece of metal may be kept hot for any length of time ; 
 so that if heat be pressed out, the quantity must be inexhaust- 
 ible.* When any body is codled, it occupies a smaller volume 
 than before : it is evident, therefore, that its parts must have 
 approached towards each other. When the body is expanded 
 by heat, it is equally evident, that its parts must have sepa- 
 rated from each other. The immediate cause, then, of heat, 
 is motion, and the laws of its communication are precisely the 
 same as the laws of the communication of motion." 
 
 111. "Since all matter may be made to fill a smaller vo- 
 lume by cooling, it is evident that the particles of matter must 
 have space between them ; and since every body can communi- 
 cate the power of expansion to a body of a lower temperature ; 
 
 * It is certainly inexhaustible while any of the metal remains to be condensed 
 by the pressure and friction. 
 
 . I - <h^ CM 
 
 ' 
 
TERRESTRIAL MAGNETISM. 41 
 
 that is, can give an expansive motion to its particles, it is a pro- 
 bable inference, that its own particles are possessed of motion ; 
 but as there is no change in the position of its parts as long 
 as its temperature is uniform, the motion, if it exist, must be 
 a vibratory or undulatory motion, or a motion of particles 
 round each other." 
 
 112. We have called the attention of the reader to this 
 passage, because it has influenced the opinions of many other 
 writers both in England and in this country ; and because 
 we think it fundamentally erroneous. 
 
 113. A remarkable proof of the mechanical force of calo- 
 ric was exhibited the other evening in this city, while we 
 were writing about it. On the 7th of May, about eight 
 o'clock in the evening, the porter and victualling house of 
 Mr. Woodward, 553 Grand Street, was struck by lightning, 
 and considerable injury done to the wall and property. 
 Thence it passed off across the street in an oblique direction, 
 and struck the house of Mr. Sweesey, corner of Mangin and 
 Grand Streets, entering near the eaves under a dormant win- 
 dow, which was shivered to atoms ; while a lady who sat 
 near it happily escaped unhurt. In its passage through the 
 house, it overturned a bedstead and bed completely upside 
 down, injured the furniture, and upset a barrel of pickles in 
 the lower part of the house. The hole which it made in en- 
 tering was nearly as large as a barrel. ( Vide New - York 
 Courier and Enquirer.) 
 
 114. We have taken this general view of caloric, for the pur- 
 pose of showing the various appearances which it exhibits, 
 under different circumstances. There are strong reasons for 
 believing, that the aurora borealis and australis, is one of the 
 
42 A NEW THEORY OP 
 
 forms of caloric, which is given out by the upper current of the 
 atmosphere, as it passes to the poles. 
 
 115. It is a well known law, that all matter gives out caloric, 
 in passing from a rarer to a denser state ; and we know that 
 the density of the atmosphere greatly increases as we advance 
 from the lower to the higher latitudes. We also know that 
 the atmosphere, like all other bodies, owes its bulk to caloric. 
 Hence it follows, that caloric must be given out, by the atmos- 
 phere, as it passes from a rarer to a denser state. M. Hansteen 
 says "that it is a matter of common observation, in the arctic 
 regions, confirmed by long experience, that the aurora borealis 
 is accompanied by intense cold, especially after a mild day. 
 He adds further, that while the aurorse are streaming, the sky 
 becomes opaque or misty. He thinks that the aurora takes 
 from the transparent aqueous vapor a portion of its caloric, and 
 that it first becomes luminous on passing out of the atmo- 
 sphere." M. Hansteen also states, that the aurorae are accom- 
 panied by an increase of magnetic intensity that, when they 
 are vivid, the horizontal needle is restless, quivers, and varies 
 from three to five degrees from its ordinary place. (See 
 Edinburgh Philosophical Journal, Vol. 12, p. 89.) 
 
 116. It is not a little surprising that M. Hansteen was not 
 led by these facts to the theory above suggested. He considers 
 the aurora as " probably the result of a struggle of powers put 
 in activity by the variously constituted substances composing 
 the mass of the earth, which we may one day, perhaps, learn 
 to know," " That it decomposes the aqueous vapor of the 
 polar atmosphere, thus producing the polar fogs" from which 
 it is evident that M. Hansteen's views of this singular pheno- 
 menon were vague and indefinite. 
 
TERRESTRIAL MAGNETISM. 43 
 
 117. Notwithstanding the amount of caloric given out by 
 the upper equatorial currents as they pass to the poles, very 
 little effect is produced by it in moderating the climate, as it 
 escapes into the vacant regions above where not being com- 
 pressed by the atmosphere, it expands like the electric spark in 
 an exhausted tube, into broad bands or zones and columns 
 filling the sky with halos, or crowns of lambent light or 
 undulating coruscations. 
 
 118. It is highly probable that the aurorse are formed in the 
 upper and rarefied regions of the atmosphere and that the dif- 
 ferent apparent heights of the columns are owing to their 
 different distances from the point of observation. 
 
 119. It is worthy of notice, that the northern lights are most 
 numerous and vivid during the long polar night, while the 
 cold is most intense, when the upper current from the equator 
 in its passage to the pole is greatly condensed ; and that 
 they are then exhibited in much lower latitudes than during 
 summer. 
 
 120. It is stated by Sir W. E. Parry and by Captain Scores- 
 by, that during winter in the high latitudes, the aurorse were 
 discovered more frequently south than north of Spitzbergen 
 and Melville Island from which we may conclude, that they 
 are rarely formed beyond the latitudes of greatest cold ; be- 
 cause the atmosphere arrives at its maximum density at the 
 limits of greatest cold. 
 
 121. It is also an important fact corroborating this view of 
 the subject, that they are seen in lower latitudes in the middle 
 and eastern portions of America, than on the western ; which 
 are known to be considerably colder than the western, in the 
 same latitudes, which is owing to the greater amount of atmo- 
 
44 A NEW THEORY OP 
 
 spheric vapor which is brought from the Pacific and Atlantic 
 oceans by the prevalent west winds of the middle latitudes, 
 and which gives out caloric during its condensation and preci- 
 pitation on the western coasts. Hence, the greater amount of 
 rain which falls on the western coasts of America and Europe, 
 than on the middle and interior portions hence, also the 
 dryness of our west winds in the United States, east of the 
 Rocky Mountains ; having deposited their vapor on the western 
 side before reaching the interior. These facts enable us to 
 understand why our west winds are dry while in England 
 and France they are wet, and east winds dry. 
 
 122. The aurora is seen much oftener in Vermont (between 
 latitude forty-two and forty-four degrees N.) which is a cold 
 mountainous state, than in France or England, though they 
 are much farther north. General Martin Field has recorded 
 in the American Journal of Science, that during the year 
 1830-31, the aurora was perceived on fifty-six nights; and 
 that during' ten years previously it was observed eighteen 
 nights on an average, annually, at Fayetteville, Vt. 
 
 123. We have been asked why the aurorae are not continu- 
 ally formed, as the atmosphere is perpetually flowing from the 
 tropical to the higher latitudes ? We might as well be asked 
 why there is not perpetual thunder and lightning while the 
 atmosphere is charged with vapors moving from the sea over 
 the land ? The condensations which occur in both cases are 
 temporary and unequal, and depend on the relative tempera- 
 tures of different aerial masses. When the upper current of 
 warm atmosphere charged with vapor, comes in contact with 
 the cold air of the polar regions, it gives out a large portion of 
 
TERRESTRIAL MAGNETISM. 45 
 
 caloric, and the aurorse are vivid ; but when the condensation 
 is less considerable, the caloric is given out imperceptibly. 
 
 124. The aurora is probably given off during the condensation 
 of the upper equatorial current, with the vapor which it con- 
 tains, in a mode similar to the evolution of silent lightning of 
 a summer evening, which produces a lambent light, much 
 more like the aurora than common lightning. It is highly 
 probable, that the electric fluid is nearly all given out before 
 the upper current reaches the centre of maximum cold, which 
 explains why the aurora is less brilliant at Melville Island, 
 than at Bear Lake, the Shetlands, Orkneys, &c. It also 
 explains why in the coldest regions as at Port Bowen, Winter 
 Island, &c., the magnetic needle was not sensibly affected by 
 it, as in the United States, and in the north of Europe ; and 
 why in the former places it was almost always seen by the 
 British navigators southward of them. 
 
 125. Siberia, Lapland, and the Norwegian Alps, are distin- 
 guished by the frequent display of this beautiful meteor. It is 
 said by Bergman " that persons travelling over the high 
 mountains of Norway have been enveloped in it." It is also 
 stated by Captain Cook and other voyagers, that it is frequently 
 seen in the southern hemisphere, south of Van Diemen's land, 
 and off Cape Horn, where the cold is excessive. 
 
 126. We have said that caloric is the source of life and mo- 
 tion in organized beings. Whether this opinion be well or ill 
 founded, it has been maintained by many of the most wise 
 and distinguished philosophers of both ancient and modern 
 times. Heraclitus taught that " fire was the primordial princi- 
 ple of the generation of all things." It was the opinion of the 
 Pythagoreans "that heat or fire was the principle of life, 
 
46 A NEW THEORY OF 
 
 animating the whole system of nature, and penetrating all 
 the elements." 
 
 127. " The Platonists likewise held fire to be the immediate 
 natural agent, or animal spirit; to cherish, to warm, to enlight- 
 en, to vegetate, to produce the digestions, circulations, secretions, 
 and organic motions in all living bodies, animal and vegetable." 
 
 128. " Hippocrates, in his treatise on diet, speaks of a strong 
 but invisible fire, which rules all things without noise, and is 
 never in repose ; which is the cause of motion, change, growth, 
 diminution, &c., which actuates and animates the whole 
 world." (See Bishop Berkley's Siris.) 
 
 129. That there is a subtle vivifying principle disseminated 
 throughout nature, and which is intimately connected with 
 caloric, would appear from the effect of cold on the various 
 tribes of animal and vegetable existence. 
 
 130. Who has not rejoiced, after a long and dreary winter, 
 at the return of warm and genial spring, when all nature 
 seems regenerated, and bursts forth into a new existence, 
 under the enlivening influence of the solar rays ? Rich ver- 
 dure clothes the fields and forests. Sweet scented flowers 
 spring up on every side, filling the air with delicious odors. 
 The birds break forth into song, and all nature resounds with 
 gladness and melody. But in the dreary regions of perpetual 
 congelation, no sounds of life are heard ; an awful stillness 
 reigns and nature seems to have lost the power of pro- 
 duction. 
 
 131. We know that life cannot exist without a continual 
 supply of atmospheric oxygen. We also know that oxygen 
 undergoes a chemical change in the lungs by respiration 
 that it unites with carbon and that caloric is developed 
 
TERRESTRIAL MAGNETISM. 47 
 
 during all its combinations with other matter. We are 
 not to suppose, however, that atmospheric oxygen is absorbed 
 by the lungs, and conveyed into the circulation by respira- 
 tion. It is the latent caloric of oxygen which warms the 
 heart, and stimulates it to send the blood throughout the 
 system. 
 
 132. When treating of galvanic heat, we observed, that its 
 energy was proportional to the extent of oxidation of the me- 
 tallic plates ; so, in living beings, the animal heat imparted to 
 them by respiration, is proportional to the amount of oxygen 
 consumed: which must depend on the size and activity of the 
 respirable organs. From the lungs it is conveyed with the 
 blood to all parts of the system by secretory action. The ca- 
 pillary vessels themselves, being vivified by this element, mo- 
 dify the blood into different substances, according to their 
 structure, health, disease, &c. 
 
 133. In birds the animal heat is higher than in man arid 
 quadrupeds ; while in cold blooded animals the temperature is 
 low in proportion to the diminished size and activity of their 
 respirable organs. In vegetables, whose respiration and cir- 
 culation are irregular, the temperature varies with the season 
 of the year, and the state of their foliage or lungs. 
 
 134. Dr. Wilson Philip performed the following experi- 
 ments some years ago, for the purpose of ascertaining whether 
 galvanism and the nervous fluid were identical. He divided 
 the eighth pair of nerves, which are distributed to the stomach 
 and lungs, by incisions in the necks of several living rabbits. 
 After the operation, the parsley which they ate remained with- 
 out alteration in their stomachs ; and the animals, after 
 evincing much difficulty of breathing, seemed to die of suffo- 
 
48 A NEW THEORY OF 
 
 cation. But when in other rabbits similarly treated, a mode- 
 rate current of galvanic electricity was transmitted along the 
 nerve, below its section, to a disc of silver, placed closely in 
 contact with the skin of the animal, opposite to its stomach, 
 no difficulty of breathing occurred. The voltaic action being 
 kept up for twenty-six hours, the rabbits were then killed, and 
 the parsley was found in as perfectly digested a state as that 
 in healthy rabbits fed at the same time ; and their stomachs 
 evolved the smell peculiar to that of a rabbit during digestion. 
 The experiments were several times repeated, with similar 
 results. (See Philip's Inquiries into the Laws of Organic 
 Life.) 
 
 135. He also proved,* that, whatever the nervous fluid may 
 be, it is received into the system by respiration. He rendered 
 rabbits insensible by a blow on the occiput ; the spinal marrow 
 and brain were then removed, and the respiration kept up by 
 artificial means when the motion of the heart, and the circu- 
 lation, were carried on as usual showing, that while caloric 
 was imparted to the system by respiration, the mutilation and 
 destruction of the most important organs, did not destroy life. 
 
 136. One thing is certain : that innumerable forms of life 
 spring from, or at least accompany the presence of caloric ; 
 while its absence is always attended by the entire extinction 
 of life. Hence it would appear unphilosophical, to call in the 
 aid of some other unknown imponderable aura as a vital 
 principle, when the agency of caloric, united (though we 
 know not precisely in what manner,) to the various forms and 
 combinations of matter, explains the phenomena quite as 
 well. 
 
 * If his experiment was fairly performed. 
 
TERRESTRIAL MAGNETISM. 49 
 
 137. There can be no doubt, whatever the vital principle 
 may be, that it is united with oxygen and imparted to the 
 organism by respiration. Now if it be contended that it is 
 not caloric, but some other imponderable essence, united with 
 oxygen, the difficulty is still the same, inasmuch as it fails to 
 reanimate the dead body, though oxygen be poured into the 
 lungs by artificial respiration : owing to the cessation of those 
 actions by which atmospheric air is decomposed in the lungs, 
 and the caloric of its oxygen given out and distributed 
 through the system. I would ask any physiologist this sim- 
 ple question, could life be supported by respiration, if it 
 were possible to respire oxygen without caloric ? It is obvi- 
 ously necessary to the existence of atmospheric air. 
 
 138. My friend, Dr. Caldwell, objects to caloric as the 
 primordial principle of life, because its application to a dead 
 body, will not restore irritability and sensibility. The reason 
 is, that after the organic relations have been deranged, the 
 blood coagulated, and the heart paralized, caloric cannot be 
 circulated through, and combined with the organism in the 
 same state and proportion it was by respiration, secretion, &c. 
 
 139. The states and affections of caloric are infinitely di- 
 versified by the various modes of its combination with ponde- 
 rable matter. That the lower orders of life are often instituted 
 by its union with dead animal and vegetable matter in a state 
 of decomposition, can scarcely be controverted. It is notorious 
 that thousands of species of animalcules, insects, and cryptoga- 
 mous vegetables, such as molds, confervse, &c., spring from 
 the putrefactive process, under the vivifying influence of solar 
 heat : so that irritability, the fundamental property of life, 
 
50 A NEW THEORY OF 
 
 seems to result from the union of this subtle element with 
 ponderable matter in a state of decay. 
 
 140. He who wishes to behold the simplest gradations of 
 life, as they emerge from a state of inanimate existence, has 
 only to enter some deep mine, where unmolested by winds 
 and changing temperature, molds and mosses cover the damp 
 walls. Their fragile and gossamer filaments seem to be com- 
 posed chiefly of water : a breath will destroy them. Now it is an 
 interesting query, whether these synple and evanescent forms 
 of life have any other origin than spontaneous production. If 
 they have, the evidence is beyond our scrutiny. How stupen- 
 dous that Wisdom which has so ordained the laws of nature, 
 that teeming life, springs from death ! 
 
 "Throughout the air, the ocean, and the earth, 
 See matter quick, and bursting into birth." 
 
 POPE'S ESSAY NO MAN. 
 
 141. The truth is, that we live, move, and breathe con- 
 stantly, in an atmosphere of unseen, but living fire. It is that 
 which gives beauty and lustre to the blue empyrean dome 
 which dissolves and suspends the waters of the ocean on 
 high and which lets them fall in " fruitful showers to cheer 
 the plains below." It is the active spirit of the storm and 
 tempest while it clothes the fields with living green, and 
 causes all nature to rejoice. 
 
 142. Whoever unfolds aright, the grandeur and harmony of 
 these manifestations of Infinite Wisdom, may be said, in the 
 language of the eloquent Galen, " to chaunt a solemn hymn 
 of lofty adoration to the great Author of the universe." 
 
 143. Observations were made with the microscope some 
 years ago in France, which led some philosophers to adopt 
 
TERRESTRIAL MAGNETISM. 51 
 
 the ancient doctrine, that .ill the elementary atoms of matter 
 were alive that they were composed each of separate, moving 
 animalcules, In short, that all nature was alive. Now there 
 can be no doubt that the atoms of all matter are more or less 
 in perpetual motion, caused by the transitions of caloric from 
 one portion, to another. These chemical motions were proba- 
 bly mistaken for animalcular movements. 
 
 144. It is self evident that oxygen which supports combus- 
 tion by giving out caloric, is also the supporter of animal life. 
 When the oxygen of the atmosphere is inspired, it is charged 
 with caloric positively when expired, in combination with 
 carbon, it is negative ; having imparted a portion of its caloric 
 to the blood. The same thing is true in every case of oxida- 
 tion or combustion, respiration of plants, &c. This is a law of 
 vast importance, and explains almost every chemical combina- 
 tion which takes place throughout matter. 
 
 145. How is it that carbonic acid gas, when inhaled, de- 
 stroys animal life ? Is it owing to the insufficient supply of 
 caloric it affords ? It cannot be by a poisonous operation, be- 
 cause it is formed continually in the lungs, and is therefore in 
 perpetual contact with them. It must be owing to the fact 
 of its having lost that portion of latent caloric, which is neces- 
 sary to vital action. 
 
 146. We have endeavored to prove that caloric is the cause 
 of capillary and cohesive attraction that its existing in dif- 
 ferent states in different elements, is the cause of chemical 
 attraction, and that its unequal distribution in different bodies, 
 causes an attraction between distant, as well as proximate 
 masses. 
 
 147. To say that it is the bond of union between the hea- 
 
52 A NEW THEORY OF 
 
 venly bodies, might be considered too bold a stretch of gene- 
 ralization. It must be acknowledged, however, that the sun 
 is one million times larger than the earth. If then, the sun 
 contains one million times as much caloric as the earth, he 
 must be positive in relation to all the planets and comets- 
 while they are negative in relation to him. Sir Isaac Newton 
 maintained, that there must be some connecting medium be- 
 tween the celestial bodies by which they are retained in their 
 orbits, which he called " ether," and which he supposed was 
 more subtle than light. Does not caloric answer to this subtle 
 medium ?* Does it not extend from the centre, to the circum- 
 ference of the universe ? Is it not the cause of all the mo- 
 tions and transmutations of terrestrial matter ? of decompo- 
 sition and re-combination of secretion, nutrition, growth, 
 &c ? Is it not the semperviving energy of universal nature ? 
 148. Jf the facts and principles which we have thus endea- 
 vored to unfold, be founded in truth, we can perceive no limits 
 to their application. They are intimately connected with all 
 the phenomena of living and dead matter, and therefore with 
 every department of human knowledge. The philosophy of 
 chemical affinity is still in its infancy, and presents a far more 
 extensive field for discovery, than has ever yet been explored, 
 He who enters upon it with enlarged views, and cultivates it 
 with unwearied application, will greatly extend the bounda- 
 ries of science, and will derive from his labors more imperish- 
 able renown, than that of the conqueror who wades to a dia- 
 dem, through the blood and tears of suffering humanity. To 
 
 * If we suppose caloric to be the cause of gravity, we must also suppose, that 
 it is itself without gravity otherwise we shall only explain the phendlnena of 
 gravity by itself, which would be absurd. 
 
TERRESTRIAL MAGNETISM. 53 
 
 control the operations of nature, and render her elements sub- 
 servient to the happiness of millions, is the most noble prero- 
 gative of enlightened and philanthropic man ; and raises him 
 to communion with the ever blessed SPIRIT OF ETERNAL 
 TRUTH, to whom be ascribed all glory and dominion, for ever. 
 
 NOTE. The ensuing paragraph should have followed section 18 ; but we had not 
 examined Doctor Turner's Chemistry until part I. was printed off. 
 
 Dr. Turner says " that the specific gravity of spermaceti oil, is less than that of 
 water, but that its capacity for caloric is only half that of water ; because, the same 
 quantity of caloric which heats a pound of water one degree, will heat an equal 
 quantity of spermaceti oil two degrees." This experiment clearly proves, that the 
 oil had previously more specific caloric in it than the waterj and not that its capacity is 
 less : therefore required less caloric to raise its sensible temperature than the water. 
 He states in another part of his work, " that it is difficult to determine whether the 
 increased specific caloric of solids and liquids at high temperatures, is owing to the 
 accumulation of heat within them, or to dilatation^ but, he believes " to dilatation." 
 He has not informed us what causes the dilatation, which is evidently the effect of ca- 
 loric between the molecules of ponderable matter, whether solid, fluid, or aerial. To 
 complete the climax of our astonishment, Dr. Turner adds, it is probable that the 
 capacity of elastic fluids in general for caloric, is inferior to that of the liquids from 
 which they are derived." Is it'not high time that errors so palpable and fundamental, 
 should be exploded'? The great principles of chemical science, seem to be less clearly 
 understood by many of our present writers, than by Dr. Black, Dr. Crawford, and 
 M. Lavosier. On the subject of caloric and electricity, they contain a heteroge- 
 neous combination of truth and error, which it is impossible for the student to dis- 
 tinguish, or comprehend. 
 

 
 

 
 A NEW THEORY 
 
 TERRESTRIAL MAGNETISM. 
 
 PART II. 
 
 IN the preceding part of this Essay, we endeavored to 
 show that capillary and cohesive attraction are owing to the 
 unequal distribution of caloric, and to its attraction for pon- 
 derable matter that the attraction of distant masses of vapor 
 by mountains, clouds, &c. ; is owing to the same cause, ope- 
 rating on a large scale. 
 
 We also endeavored to trace the origin of atmospheric 
 electricity, and to prove, that it was only one of the numerous 
 forms of caloric that it combined with water as caloric, and 
 converted it into atmospheric vapor ; but that when greatly 
 accumulated, and given out rapidly, it exhibited electrical 
 phenomena. 
 
 We further stated, that galvanic electricity was an- 
 other modification of caloric that it was evolved by the com- 
 bustion or oxidation of metals in acids or alkalies that ac- 
 cording to the experiments of M. Pouillet, electricity is given 
 out during all combustions and that it is developed like ca- 
 loric, by friction, by pressure, and by chemical decomposition 
 
 
56 A NEW THEORY OF 
 
 that they both produce the same effects on ponderable mat- 
 ter that they expand solids and convert them into fluids 
 that they convert fluids into gases and finally, that by a still 
 farther expansion of ponderable matter, they produce light of 
 every description, from that of a candle, to the solar beams 
 and even that of the aurora borealis. 
 
 We also stated, in a hypothetical way, for the purpose 
 of showing the universality of caloric, that it seemed to be 
 intimately connected with the vital principle and that it was 
 probably the bond of union among the heavenly bodies. In 
 short, that it was the cause of all the motions and changes 
 which take place throughout matter. 
 
 We shall in the next place, endeavor to point out the 
 connection between caloric and terrestrial magnetism. That 
 our object may be distinctly understood at the outset, we shall 
 lay down the following positions as the basis of our reasonings. 
 
 1. That there is an unequal distribution of temperature in 
 the tropical and polar latitudes. 
 
 2. That the unequal distribution of land and water over 
 the globe, causes unequal temperatures in given latitudes. 
 
 3. That % line passing round the globe from east to west, 
 which divides its temperature into two equal portions, is the 
 magnetic equator. 
 
 4. That the centres of greatest cold are the centres of mag- 
 netic attraction ; and that the force of attraction is proportional 
 to the intensity of cold. 
 
 5. That the prevalence of land in the tropical latitudes, 
 produces a general elevation of temperature ; while its predo- 
 minance in the higher latitudes, causes a corresponding 
 reduction of temperature. 
 
 
 
TERRESTRIAL MAGNETISM. 57 
 
 6. That the magnetic needle is apparently operated on by 
 two forces one vertical, and the other horizontal ; and that 
 the horizontal, is exclusively the directive force. 
 
 7. That the vertical force, which causes the needle to dip, 
 is probably equal on every part of the globe, when the hori- 
 zontal force is quiescent. 
 
 8. That at the magnetic equator the dipping needle is ho- 
 rizontal and that it dips gradually more and more, until we 
 approach the magnetic poles, where it becomes vertical. 
 
 9. That the horizontal intensity decreases, as the dip in- 
 creases, until we approach the regions of lowest mean tempe- 
 rature, where it vanishes, and the compass needle will not 
 traverse, but remains in whatever position it is placed. 
 
 10. That there is more than three times as much land in 
 Arctic America, as in Arctic Asia and Europe, attended by a 
 corresponding reduction of temperature, and increase of mag- 
 netic intensity. 
 
 11. That there are at least two magnetic poles in each 
 hemisphere of unequal intensities, and at unequal distances 
 from the geographical poles. 
 
 12. That these poles are not stationary, but shift from east 
 to west, and from west to east also, from north to south, and 
 from south to north. 
 
 13. That the unequal distribution of caloric in the tropical 
 and polar latitudes, is the cause of magnetic polarity. 
 
 14. That the unequal distribution of land and water, 
 causes an unequal distribution of temperature in given lati- 
 tudes, is most clearly exemplified in the different zones of the 
 American continent. Between^ the equator and the fortieth 
 degree of south latitude, there is more- than double the quantity 
 
 8 
 
58 A NEW THEORY OF 
 
 of land that there is between the equator and fortieth degree 
 of north latitude, which causes an increase of temperature of 
 several degrees in the southern hemisphere. Besides, there is 
 more than six times as much land in JNorth America between 
 latitude 40 and 80, than there is between latitude 40 and the 
 equator, which is a powerful additional cause of diminished 
 temperature in the northern portion of the western continent. 
 
 15. In conformity with this difference of temperature be- 
 tween the northern and southern portions of the American 
 continent, we find the magnetic equator in latitude 7 south of 
 the geographical equator, in Peru. 
 
 16. In the Pacific Ocean, two thousand miles farther 
 west, in longitude 126 from Greenwich, where there is no 
 land on either side of the equinoctial line, the magnetic equa- 
 tor coincides with it; but forty degrees farther west, where 
 there are a great many islands south of the equator, the iso- 
 thermal division of the two hemispheres is three degrees south 
 of it. 
 
 17. When we turn to the eastern division of the globe, 
 we perceive a striking illustration of the general fact, that 
 large bodies of land in the lower latitudes greatly increase the 
 aggregate temperature, and cause a deflection of the line of 
 greatest heat to that side of the equator where the land is 
 situated. For example; Arabia, Hindostan, and Southern 
 China, are situated in the northern hemisphere, near the 
 equator : while there is no land opposite to them in the other 
 hemisphere, except New Holland and a few small islands, 
 which causes the line of maximum heat to pass several de- 
 grees north of the equator, at unequal distances from east 
 longitude 25 to 180. 
 

 TERRESTRIAL MAGNETISM. 59 
 
 18. In Africa which extends far on both sides of the 
 equator, they come together in 25 east longitude from Green- 
 wich. Hence it appears, that the geographical equator is not 
 the true isothermal division of the globe, which would be the 
 case, if the whole planet were of uniform surface and 
 elevation. 
 
 19. The centres of greatest cold are the centres of mag- 
 netic attraction. It has been clearly demonstrated, that there 
 are^at least two great centres of magnetic attraction in the 
 northern hemisphere : one in the north of the American con- 
 tinent and the other in the north of Asia ; and that the 
 attraction of the American pole is much stronger than that of 
 the Asiatic pole. For example ; the needle obeys the Ameri- 
 can pole over two thirds of the northern hemisphere, embra- 
 cing the whole of North America, the middle and northern 
 Atlantic, nearly all Europe, North Africa, and throughout the 
 North Pacific to the West. 
 
 20. Let us now examine how far this polar attraction cor- 
 responds with the climate of North America. From the 
 thermometrical observations of Captain Franklin, Sir W, E. 
 Parry, and Captain Ross, when in quest of a north-west pas- 
 sage, we learn, that the northern portions of the American 
 continent are the coldest regions of the known world* that 
 the mean annual temperature at Melville Island, in latitude 
 74 30' is below zero ; or, from twenty to thirty degrees lower 
 than what had been assigned to the geographical pole, accord- 
 ing to the formulas of Mayer and Kirwin. 
 
 21^ When we reflect that large bodies of land are both 
 heated and cooled down much more rapidly than bodies of 
 
 * Except, perhaps, New South Greenland. 
 
60 A NEW THEORY OF 
 
 deep water, we shall not be surprised at the burning heats of 
 Africa, India, and South America ; nor at the intense cold of 
 Arctic America and Asia. Captain Scoresby estimates the 
 mean annual temperature of the Greenland Sea, in latitude 
 76, at about 18, which is nearly two degrees north of Mel- 
 ville Island. This island is almost always connected with the 
 continent by ice so that its climate is really continental. 
 
 22. The difference between the temperature of land and 
 sea is obvious from the following facts. The sun's ^ays 
 penetrate the ocean for several hundred feet, by which heat is 
 diffused through an extensive mass, while they penetrate thesur- 
 faceof the solid land only a few feet, which thus becomes greatly 
 heated during summer, and as rapidly cooled down by radia- 
 tion during winter. For the same reason, the land is hotter 
 than the ocean by day, and colder by night. The perpetual 
 motion of the sea, preserves a uniform temperature. Thus, 
 when its surface is cooled down to the temperature of 39 
 of Fareriheit, the water is condensed, sinks down, .and 
 gives place to the warmer and lighter particles, which rise 
 and take their place. Hence we perceive why in tropical lati- 
 tudes the ocean is cooler than the land, and in high latitudes 
 warmer than the land, especially during winter. When the 
 ocean is covered with ice, which is a bad conductor, it cannot 
 give out caloric to the atmosphere above it, which therefore 
 assumes the character of a cold continental wind. 
 
 23. The vicinity of Greenland and Spitzbergen, which are 
 islands of great extent, and very mountainous, must have a 
 sensible influence in lowering the temperature of the Green- 
 land Sea from which we conclude, that if the terrestrial 
 pole be surrounded with water, its temperature may be only a 
 
TERRESTRIAL MAGNETISM. 61 
 
 few degrees lower, and perhaps not even as 'low, as that of 
 Greenland and Spitzbergen or Hudson's Bay. Captain 
 Scoresby has estimated the temperature of the pole at about 
 10 ; while at Melville Island it is below zero, as already 
 stated. 
 
 24. Were it not for the existence of Greenland and Spitz- 
 bergen, the temperature of the northern Atlantic would be 
 still higher and perhaps open every summer to the geograph- 
 ical pole. Notwithstanding the immense number of icebergs 
 annually formed in the valleys of Greenland and Spitzbergen, 
 which descend into the surrounding ocean during summer, and 
 thus lower its temperature, we find that the cold is much less 
 severe in latitude 80, than in the interior of the continent in 
 latitude 65 and 70, from Hudson's Bay to Regent's Inlet. 
 
 25 .( Passing over as Professor Jameson has done, the pre- 
 tensions of the Dutch whalers, who alledged that they had 
 been carried by winds and currents as far north as the latitude 
 of 88, or even 89 40', we cannot reasonably doubt the well 
 authenticated accounts of Wilson and Guy, who respectively 
 advanced to the latitude of 83, during the year 1754, and of 
 Stephens, who advanced to latitude 84 30' about the same 
 period. They all state, that the sea was open as far north of 
 them as they could descry, and that the cold was by no means 
 excessive. 
 
 26. " From all the above facts taken together, we are 
 authorized to believe, that the mean temperature of the terres- 
 trial north pole is considerably higher, than at the magnetic pole ; 
 because surrounded by water while the magnetic pole occu- 
 pies an interior continental position. It is worthy of notice, 
 that the longer exposure of the terrestrial pole to the sun du- 
 
62 A NEW THEORY OF 
 
 ring summer, 1ms a tendency to raise the temperature higher 
 during summer than in lower latitudes so as to dissolve the 
 ice which had accumulated during the polar winter. 
 
 27. There are two interesting facts by which we are en- 
 abled to determine the position of the magnetic poles one 
 is, that over the magnetic poles, the dipping needle becomes 
 vertical ; and the other is, that the horizontal needle loses its 
 directive power. 
 
 28. That there are two great centres of magnetic attraction 
 in the northern hemisphere } was known upwards of two centu- 
 ries ago. Their position and relative intensity, are of recent 
 discovery. Sir W. E. Parry wintered a few degrees north- 
 west of the American pole in 1819-20, and sailed nearly 
 over it in Prince Regent's Inlet the following summer in latitude 
 72, where his compass needles became useless. We shall 
 presently see, that this is never the case, except about the 
 centres of maximum cold. 
 
 29. Professor Hansteen, of Norway, has made and collected 
 a vast number of observations in the north of Europe and 
 Asia, for the purpose of ascertaining the variation, dip, and 
 intensity of the needle, in those portions of the eastern conti- 
 nent from which he conjectures, that the Asiatic pole is in 
 latitude 85 north, and longitude 102 east of Greenwich. 
 
 30. Having thus ascertained with considerable accu- 
 racy, the positions of the two great centres of magnetic attrac- 
 tion in the northern hemisphere, we shall now endeavor to ex- 
 plain the cause of magnetic polarity. We have shown, that 
 the magnetic equator is a line dividing the temperature of the 
 globe into two equal parts. We shall next proceed to state 
 the different positions assumed by the needle in different lati- 
 
TERRESTRIAL MAGNETISM. 63 
 
 tudes. At New York, in latitude 40 Q 42' and longitude 74, 
 west, a needle well balanced on its centre, having free motion, 
 in a vertical plane, and afterwards magnetized, has an inclina- 
 tion or dip of its north end towards the centre of the earth 
 about 73, while at the magnetic equator, it is perfectly hori- 
 zontal. In the southern hemisphere, the south end dips. 
 
 31. In assuming this position, it would appear that the 
 needle is operated on by two forces ; the one vertical, and the 
 other horizontal the former caused by the attraction of the 
 earth, the latter by the unequal distribution of caloric in the 
 tropical and polar latitudes. That the north end of the nee- 
 dle is attracted by the earth in this hemisphere, is evident from 
 the fact, that when placed at right angles with the magnetic 
 meridian, it assumes a vertical position ; but when turned in 
 the direction of the magnetic force, it rises. Now, whatever 
 the cause may be, which raises the magnetic needle from a 
 vertical to an inclined or horizontal position, must be the cause 
 of polarity ; and the angle of inclination must be the inverse 
 measure of its horizontal intensity. 
 
 32. At the magnetic equator, both these forces act equally 
 on both ends of the needle ; the consequence of which is, that 
 the needle assumes the horizontal position. When it is re- 
 moved to the magnetic pole, or centre of maximum cold, there is 
 no horizontal force exerted on it to raise it from the vertical 
 position : from which it is obvious, that if there were no other 
 force exerted on the needle than that of the earth's central 
 attraction, it could never polarize. 
 
 33. It is admitted by nearly all writers on magnetism, that 
 in the northern hemisphere, the north end of the needle is 
 positive, while the south end is negative. In the southern 
 
64 A NEW THEORY OF 
 
 hemisphere, the south end is positive in the same way, while 
 the end which points to the equator is negative in relation to 
 it. We before stated, that in both hemispheres, the polar ends 
 of the needle inclined towards the earth in proportion as we ad- 
 vance towards the magnetic poles. Now if the earth be negative 
 in relation to the polar ends of the needle, they must be at- 
 tracted by it, for the same reason that the opposite poles of a 
 magnet attract each other, which, together with the diminished 
 horizontal intensity, must cause the polar ends of the needle 
 to dip. 
 
 34. Mr. Read, of Knightsbridge, observed, that when the 
 atmosphere was transparent, lightning rods were charged with 
 electricity by induction, the upper ends being negative, and the 
 lower ends positive ; while a portion of the rod towards the 
 middle was neutral. (See Thomson on Caloric and Elec- 
 Iricity, p. 446.) 
 
 35. However inexplicable this may appear, it is precisely 
 analogous to what we find in the magnetic needle, and the 
 analogy is a curious subject of inquiry. A dry atmosphere 
 electrifies negatively, that end of the rod which is nearest to it, 
 and positively the end which is furthest off. So likewise, the 
 equatorial zone is certainly positive, yet those ends of the 
 needle in both hemispheres, which are directed towards the 
 magnetic equator are negative, while the polar ends are 
 positive. Who is able to explain this 1 
 
 36. In the preceding part of this essay, we proved that it 
 was the universal tendency of caloric to pass from where it 
 is plus to where it is minus, that distant masses of vapor, un- 
 equally charged with caloric, attract each other, and are at- 
 tracted by mountains, &c. 5 until the equilibrium is restored. 
 
TERRESTRIAL MAGNETISM. 65 
 
 when the attraction ceases. Now we know, that caloric is 
 greatly accumulated in the tropical regions, and that it exists 
 in comparatively small quantities in the polar regions con- 
 sequently, that there must be a perpetual flow of caloric in 
 those directions in search of an equilibrium : from which we 
 infer, that if the temperature of the equatorial and polar regions 
 could be equalized, the horizontal or directive power of the 
 needle would also cease. 
 
 37. It may be contended, that the passage of caloric from 
 the tropics to the poles is not the cause of magnetic polarity, 
 because during summer, the interior of the United States is 
 frequently warmer than the tropical ocean, while the sun is 
 above the horizon and that, therefore, the calorific currents 
 would be towards the tropics. It is true, that while the diur- 
 nal temperature of the magnetic equator, on the ocean, is about 
 83, the thermometer often rises to 90, and sometimes higher, 
 at New York, Boston, and Philadelphia, in latitude 40, 41, 
 and 42. We should not forget, however, that during this period 
 of high summer temperature at New York, it is about 32 at 
 the magnetic pole ; so that there is a much greater flow of 
 caloric from New York to Melville Island, than from New 
 York to the magnetic equator. 
 
 38. In accordance with this condition of things, we find, 
 that the magnetic intensity is weaker during summer than 
 winter, when the difference between the temperature of the 
 equator and the magnetic poles is considerably increased ; 
 being from about 85 above, to 40, or 50, and even 58 
 below zero. 
 
 39. That invisible force which directs the needle, whatever 
 it be, must be a material agent, every where present on the 
 
66 A NEW THEORY' OF 
 
 globe ; but we have proved that caloric is every where present, 
 and that it is unequally distributed in the lower and higher 
 latitudes. It was demonstrated by Scheele fifty years ago, 
 " that radiant heat passes through the air without heating it, 
 and that no aerial currents, however strong, have any tendency 
 to intercept it." (See Thomson on Caloric and Electricity, 
 p. 131.) 
 
 40. It is highly probable, that a great portion of the earth's 
 radiant heat passes upwards into the higher regions : it can- 
 not be maintained, however, that caloric is radiated upwards 
 only. A horizontal radiation was clearly demonstrated the 
 other day, when the City Hotel was on fire, as it is in every 
 case of combustion. 
 
 41. Perhaps it may be safe to state in general terms, that 
 one half of the caloric received by the earth from the sun, 
 escapes by radiation ; and that the remainder combines 
 with surrounding bodies, and thus becomes latent. We 
 know that a large proportion of solar heat is continually 
 entering into solids and converting them into fluids and 
 gases ; and that the balance passes off by radiation to those 
 bodies which contain less of it. That portion of the matter of 
 light which is not caloric, probably combines with the ponder- 
 able matter of the earth, and thus loses its phosphorescent pro- 
 perties, becoming a portion of common matter. Sir Isaac 
 Newton asks the question, " are not light and common matter 
 convertible into each other." 
 
 42. We have already stated, that the northern parts of our 
 own continent are the coldest portions of the known world. 
 That they are greatly colder than the north of Asia and 
 Europe is demonstrable from the fact, that it contains more 
 than three times as much land within the arctic circle, as Asia 
 
TERRESTRIAL MAGNETISM. 67 
 
 and Europe. This fact, according to our theory, explains 
 why the magnetic needle obeys the American pole over 240 
 of longitude, which embraces two-thirds of the northern hem- 
 isphere while it points to the Asiatic pole over only 120 of 
 longitude. 
 
 43. If the whole northern hemisphere were of uniform sur- 
 face and elevation, its temperature would be also uniform in 
 given latitudes ; and its point of greatest cold would be at the 
 terrestrial pole : but as the surface of the earth is diversified by 
 land and water by elevated mountains and deep valleys by 
 rocky hills and verdant meadows by desert plains and by 
 dense forests, its temperature varies greatly in the same lati- 
 tudes, hence, in the northern interior of America, the mercury 
 falls to 50 and 58 of Farenheit below zero during winter ; 
 while on meridians surrounded with water, we find the tem- 
 perature from fifteen to twenty degrees warmer in the same 
 latitudes. 
 
 44. The existence of different magnetic poles or centres of 
 cold in each hemisphere, situated at unequal distances from 
 each other, and from the poles of the earth's axis, produce all 
 the phenomena of magnetic variation, which it must be ac- 
 knowledged, has hitherto been involved in the deepest obscurity. 
 If the' whole northern hemisphere were level and of uniform 
 surface, there could be but one magnetic pole or centre of 
 maximum cold, which would be at the geographical pole : 
 consequently, the needle would always point in the direction 
 of the geographical meridians, and there would be no variation 
 of the compass. We should not be perplexed as we now are, 
 with the oblique and devious character of the lines of no varia- 
 tion. The whole would be perfectly simple and intelligible 
 
68 A NEW THEORY OF 
 
 to the meanest capacity. The dip and intensity of the needle 
 would be the same in given latitudes and we should only 
 have to account for the cause of its polar direction. 
 
 45. Perhaps no subject has more puzzled philosophers, 
 than the unequal temperature of climates at different periods. 
 Some few have doubted the fact, while others have endea- 
 vored to account for it in various ways. Dr. Brewster sup- 
 posed that the centres of greatest cold, have a periodic revo- 
 lutionary movement round the geographical poles and that 
 " the cold meridians which now pass through Canada and 
 Siberia, formerly passed through Europe, causing the coldness 
 of ancient Italy, as described by several Roman writers ; who 
 relate that the Tyber had been frequently frozen over that 
 snow lay on the ground for forty days at Rome that the 
 Euxine sea was frozen over every winter in the time of 
 Augustus that the Rhine and Rhone sustained loaded 
 waggons, &c." (Edin. Ency.> Art. Polar Regions.} 
 
 46. In accordance with the facts which we have stated 
 in relation to the cause of unequal temperature in given lati- 
 tudes, it is difficult to understand with Dr. Brewster, how the 
 " meridians of greatest cold," which now pass through Ame- 
 rica and Asia, can revolve round the terrestrial pole, though 
 we may conceive, without any violent hypothesis, that in 
 former times, there was a third minor centre of cold in the 
 neighborhood of Greenland and Spitzbergen and that its 
 influence extended for limited periods, over a large portion of 
 western Europe. This appears to have been the case in mo- 
 dern times. The Greenland Sea, which was quite open and 
 navigable from the eighth to the fourteenth century, became 
 afterwards filled with ice, and so remained, according to dif- 
 
TERRESTRIAL MAGNETISM. 69 
 
 ferent liistorians of Greenland, for nearly three centuries, so 
 as to cut off all communication with Iceland and Norway, 
 during the above period. An explanation of this singular 
 phenomenon will throw much light on the difficult and 
 important subject of terrestrial temperature. 
 
 47. It is not our present purpose to inquire how far the 
 temperature of the globe has been altered during ancient 
 epochs, by geological revolutions of its surface. Suffice it to 
 say, that the fossil remains found imbedded in the transition 
 and secondary formations throughout the American continent, 
 from Alabama to Melville Island, demonstrate, that they were 
 deposited on the floor of an ancient sea and that its tem- 
 perature was then much higher in northern latitudes, than at 
 the present time. It is easy to conceive that a predominance 
 of land in the tropical latitudes, and of water in the higher 
 latitudes, would totally alter the distribution of heat through- 
 out the globe and that under such circumstances, a tropical 
 temperature would extend to the arctic circle. 
 
 48. This view of the subject enables us -to understand the 
 diffusion of animals and plants in the older formations, whose 
 analogues are now found only in the tropical regions. Mr. 
 Lyell has termed this ancient condition of the globe, " a sum- 
 mer of the great geological year" He also maintains that 
 the elevation of the western and eastern continents above 
 that ancient sea, has produced a complete change of climate 
 throughout the globe, and an entire extinction of numerous 
 tribes of animals and vegetables, whose history is known 
 only by their fossil remains. 
 
 49. To illustrate this subject still further, Mr. Lyell has 
 supposed, that if in the progress of geological revolutions, the 
 
70 A NEW THEORY OF 
 
 dry land of the tropical regions should disappear, and high 
 mountains, such as the Himmalehs and the Andes, should rise 
 in the polar regions, (and he thinks it evident, that changes 
 equally great have taken place,) the cold would be such as to 
 destroy numerous tribes of animals and plants which now 
 exist and that we should then have what he terms, " the 
 winter of the great geological cycle" (See Principles of 
 Geology, by Charles Lyell, F. R. &,) where this subject is 
 treated in a masterly manner. However fanciful and strange 
 the above speculations may appear to those unacquainted with 
 Geology, they are founded on a series of demonstrated facts, 
 by a course of the most rigid philosophical induction. 
 
 50. We shall now return to the vicissitudes of climate which 
 have marked the more recent periods of the earth's history. 
 
 51. It is highly probable that there is usually a greater 
 barrier of ice accumulated in the latitudes of 80 and 81? 
 around Greenland and Spitzbergen, than in the ocean farther 
 north ; for this reason, that the field ice which is broken up 
 during spring in the Arctic .Sea, and floated by currents 
 towards the south, is obstructed in its passage by the northern 
 coasts of Greenland and Spitzbergen, where it accumulates, 
 forming impassable walls of ice. This is rendered the more pro- 
 bable from the numerous accounts of Dutch and English navi- 
 gators, engaged in the whale fishery, having advanced as high 
 as 842, and some still farther, who all agree, that the sea 
 was open as far as they could see from the mast head. 
 Danes Harrington, Esq., a member of the Royal Society of 
 London, has collected a mass of testimony on this subject, 
 which it is impossible to disregard. When Captain M'Callam 
 advanced as far as 83 J in the year 1751, he found the sea 
 
TERRESTRIAL MAGNETISM. 71 
 
 open, and would have proceeded farther but for the mate, who 
 complained that the compass was not steady, when the 
 captain reluctantly returned. 
 
 52. There can be no doubt, that there is more ice in Baf- 
 fin's Bay, in latitude 73 ; or in any other portion of the sea, 
 bordering on the continent, than there is farther north, where 
 there is no land. Such is my conviction, that it is the land, 
 and the icebergs formed in mountain valleys, which lowers 
 the temperature of the sea, that I am strongly inclined to 
 credit the accounts given by Barrington, of two Dutch whalers 
 having proceeded as high as latitude 89, where they found 
 the sea quite open. It is much to be regretted that they 
 made no observations with a dipping needle while in those 
 high latitudes. They state, however, that the compass 
 needle pointed to the south-west ; as with Captain Parry in 
 latitude 74, and longitude 110 west, it pointed south-east to 
 the magnetic pole. 
 
 53. It is impossible to assign any rational cause why 
 during one period the northern seas should be open, and 
 during other periods closed, without admitting the obstruction 
 of field ice by the frozen coasts and by icebergs, on its passage 
 to lower latitudes ; by which the climate of the surrounding 
 ocean acquires for a time a continental character. Captain 
 Franklin saw icebergs aground in Baffin's Bay, in fifteen 
 hundred feet water. If then we admit the occasional descent 
 into the surrounding sea of a large number of icebergs, from 
 the rivers and valleys of Greenland and the northern conti- 
 nent, we may easily comprehend how they would lower the 
 temperature of the ocean, obstruct the field ice, and cause it to 
 accumulate for thousands of square miles. When once the 
 
72 A NEW THEORY OF 
 
 mass became cemented, it would augment by every fall of 
 snow and rain, until it became sufficiently strong to resist the 
 power of the waves. During this condition of the Arctic seas, 
 the polar winds would pass over them without receiving any 
 warmth and hyperborean rigors would extend to the middle 
 latitudes. 
 
 54. Coinciding with this period of diminished temperature 
 in the Greenland Sea, we find the most satisfactory evidence 
 of a corresponding change of climate in England. 
 
 55. William Prince, Esq., of Long Island, who has pub- 
 lished an exceedingly interesting History of the Vine, states, 
 on the authority of several Roman and English writers, that it 
 was introduced into England from Italy, at least as early as 
 the year 280 of the Christian era, during the reign of Probus, 
 if not earlier, as some historians have maintained. It con- 
 tinued to flourish in all the southern counties of England, until 
 the reign of Henry the Eighth, when it began to decline ; 
 and about the year 1560, during the reign of Elizabeth, it had 
 entirely ceased to mature its fruit, without artificial warmth. 
 It is now the opinion of some horticulturists in England, 
 that the climate is becoming adapted to its growth, and that it 
 will again flourish as formerly.* 
 
 56. Corresponding with this opinion, there is an almost 
 universal impression throughout the United States, that the 
 winters are shorter and less severe than formerly. Mr. Jeffer- 
 son, Dr. Rush, and Williams, the historian of Vermont, all 
 relate, that in their respective states, the falls were later the 
 rivers froze later, and broke up earlier in the spring that 
 
 * We are informed, that in the time of Strabo, it was impossible to mature 
 the fruit of the vine in France, north of the Cevennes. 
 
TERRESTRIAL MAGNETISM. . 7S 
 
 snows were neither so heavy nor so frequent as they were 
 from the first settlement of the country to within seventy years 
 ago. Volney says, it was a general opinion throughout the 
 United States and Canada when he was here, that n the sum- 
 mers were longer, the winters shorter, snows lighter, and 
 cold less violent, than in former times." Jefferson, Wil- 
 liams, and Volney, attributed this change to the clearing 
 of the country, and to the general progress of cultivation. 
 There can be no doubt that a cleared country is hotter during 
 summer, than one covered with forests ; buMt is also colder 
 during winter. 
 
 57. Corresponding with the milder character of the Ame- 
 rican climate for the last sixty or seventy years, we learn from 
 Captain Scoresby, that the Greenland Sea is so far open at 
 present, that he thinks the eastern coast might be approached 
 every summer. It' is easy to conceive, that while the Green- 
 land Sea (which is only an immense strait, about 1000 miles 
 wide, connecting the Atlantic with the Arctic Ocean,) was 
 closed, it obstructed the annual passage of ice from the polar sea 
 into the Atlantic, so that the Arctic Sea must have remained 
 covered with ice for ages, giving a continental climate to a 
 great portion of the polar ocean and thus permanently low- 
 ering its temperature many degrees, by which the climate of 
 Canada and the United States, must also have been rendered 
 colder. 
 
 58. During the period of accumulated ice in the Green- 
 land Sea, the winters were extremely cold in England. 
 Dr. Webster states, in his History of Epidemics, that during 
 
 the winter of 1683-4, trees of large size split open with the 
 
 10 
 
74 A NEW THEORY OF 
 
 frost and that the same winter was excessively severe in 
 America. (See vol. 1, p. 204.) 
 
 59. " The winter of 1779-80, was more severe in America 
 than had- been experienced for a great many preceding 
 years. The mercury fell to twenty-six degrees below zero, 
 on the llth of January, at Hartford, Connecticut, in latitude 
 41 44'." Dr. Webster also states, (the authority not given,) 
 that " during the same winter,, which was excessively cold in 
 Britain, the mercury fell to forty-six degrees below zero at 
 Glasgow;" which we think very doubtful. It is highly 
 probable, that the winters of 1830-1, and 1831-2, were the 
 coldest that have been experienced in North America, since 
 1779-80. 
 
 60. Mr. Darby* has collected from the writings of the Abbe 
 Rosier, M. Mezerai, and other authentic sources, a vast num- 
 ber of facts, which prove an increased severity of the climate 
 of Europe, especially that of France, during the last three 
 centuries. He gives examples of excessive winters, from the 
 commencement of the Christian era to the fourteenth century 
 when the rivers and inland seas of Europe were covered with 
 ice ; but they were much less frequent and severe in the mid- 
 dle ages, than during the last three centuries, as the following 
 statements, considered in connection with the state of the 
 vine, renders extremely probable. 
 
 61. " A. D. 1433, frost commenced at Paris, the last of De- 
 cember, and continued during three months, less nine days 
 recommenced towards the end of March, and continued until 
 
 * See his View of the United States. 
 
I 
 
 TERRESTRIAL MAGNETISM. 75 
 
 the 17th of April. The same year it snowed in Holland forty 
 consecutive days. 
 
 "A. D. 1460, the Danube and the Rhone frozen." 
 
 " In 1468. wine was reduced to ice in France, and cut with 
 an axe. In 1544, a similar severity of cold occurred. 
 
 " A. D. 1493, the port of Genoa frozen. 
 
 " A. D. 1507, the port of Marseilles frozen in all its extent. 
 Three feet of snow fell at the same city on the day of 
 Epiphany. 
 
 " A. D. 1565, the Rhone was frozen to Aries. 
 
 "A. D. 1568, from the llth to the 21st of December, the 
 Rhone passed on the ice. 
 
 "The winter of 1570-1, from the end of November to 
 the end of February, was so severe, that all the rivers, even 
 those of Languedoc and Provence, were so completely frozen, 
 that they were passed with loaded carriages. 
 
 " A. D. 1594, the sea at Marseilles and Venice frozen. 
 
 " A. D. 1603, loaded carriages passed the Rhone on 
 the ice. 
 
 " The winter of 1621-2, the Venetian fleet arrested by 
 the ice in the lagoons of Venice ; in 1638, a similar event 
 with the French gallies at Marseilles. 
 
 " A. D. 1645, the Swedish army passed from Holstein into 
 Zealand on the ice. 
 
 "In the winter of 1655-6, the Seine was closed from 
 the 8th to the 18th of December. It was again frozen, 
 without interruption, from the 29th of December to the 28th 
 of January. A new frost recurred a few days after, and 
 continued until in March. (Bouillaud.) The ensuing win- 
 ter, 1657-8, an uninterrupted frost from the 24th of Decem- 
 
76 A NEW THEORY OF 
 
 her, to the 8th of February. Between the 24th of Decem- 
 ber and the 20th of January, the cold was moderate, but 
 afterwards acquired an extreme intensity. The Seine was 
 entirely closed. A Alight thaw took place on the 8th of 
 February, but the frost again recurred and continued to 
 18th. It was in 1658, that Charles X., king of Sweden, 
 traversed the Little Belt with his army, artillery, caissons, 
 baggage, &c. 
 
 "A. D. 1662-3. Intense frost at Paris, from the 5th 
 of December to the 8th of March. 
 
 "A. D. 1676-7, continued and very intense frost from 
 the 2d of December to the 13th of January ; the Seine was 
 closed thirty-five consecutive days.* 
 
 "A. D. 1684, the Thames, at London, frozen eleven inches 
 thick, and traversed by loaded waggoqs. 
 
 " A. D. 1709, (perhaps the most intense season which has 
 ever occurred within the range of history,) the Adriatic Sea, and 
 the Mediterranean from Genoa by Marseilles to Cette, frozen. 
 All the rivers and narrow seas of Europe frozen. 
 
 " A. D. 1716, booths erected on the Thames at London. 
 
 "A. D. 1726, sledges passed from Copenhagen to Sweden. 
 
 "A. D. 1740, the Thames, at London, again frozen." 
 
 62. ^The obstruction of the Greenland Sea by ice during 
 the fifteenth, sixteenth, and part of the seventeenth century, by 
 which the Greenland colonies from Norway and Iceland were 
 
 i * It was from about the year 1560, until early in the seventeenth century, tha 
 a distinct centre of magnetic attraction existed between Greenland and Nova 
 Zembla, which shifted irregularly, from east to west, about twenty-five degrees, 
 in the course of one hundred arid sixty years. During the above period, th< 
 needle pointed to Spit zber gen and the .Greenland Sea t throughout the west o 
 Europe, and not to the American pole, aa within the last hundred and twent; 
 
 ; years. 
 
 
TERRESTRIAL MAGNETISM. 77 
 
 cut off from all communication with Europe, presents the long- 
 est period on record of ice accumulated in the Greenland Sea, It 
 is quite probable, that during the age of the Caesars, a similar 
 accumulation existed between Spitzbergen and Nova Zembla, 
 by which the climate of Italy, and perhaps of Europe gene- 
 rally, was rendered colder than usual, as before suggested. (See 
 note, section 55.) 
 
 63. Captain Fisher, whose testimony is recorded by Bar- 
 rington, says, that it has been generally found by able and 
 experienced seamen, that there is not near the quantity of 
 fixed ice north of Spitzbergen, that there is south of latitude 
 80 as far as 74 ; which, he adds, is owing to its confinement 
 in the strait between Greenland and Spitzbergen, and to the 
 icebergs which descend from the valleys. From all the circum- 
 stances taken together, does it not appear obvious, that the Eng- 
 lish navigators in Search of a north-west passage, would have 
 had much better chances of success by proceeding round the 
 American continent, than by attempting to force a passage 
 through Lancaster Sound and Barrows' Strait, which are the 
 coldest portions of the Arctic circle ? * 
 
 64. It is highly probable, that the average temperature of 
 the northern and southern hemispheres is nearly the same ; 
 the difference being, that in the northern hemisphere, the 
 extremes are more general, owing to the larger amount of 
 land, in the tropical and middle latitudes. 
 
 65. It is worthy of notice, that the prevalent and coldest wind 
 during winter, in the middle and eastern parts of America, is 
 from the north and north-west right from the magnetic pole. 
 Such is the severity of this wind, that it has on two or three 
 occasions, reduced the temperature down to forty degrees 
 

 78 A NEW THEORY OF 
 
 below zero, in the north of this state, latitude 44, only fifteen 
 or eighteen degrees higher than the maximum cold at the 
 magnetic pole* and even as far south as Nashville, three hun- 
 dred and fifty feet above the ocean, in latitude 36 04', has 
 reduced the mercury to twenty degrees below zero, during the 
 winter of 1831-2. 
 
 66. Two opposite opinions have been advanced by two very 
 able writers on the climate of the United States, both of which 
 are true in part. M. Volney, who resided three years in the 
 United States, maintained that the climate west of the Alle- 
 ghany mountains was milder than that of the Atlantic states. 
 He seems to have been led to this conclusion from the general 
 mildness of the south and south-west winds, which prevail 
 throughout the Mississippi valley nearly three-fourths of the 
 year, while in the Atlantic states, the north-east wind prevails 
 a considerable portion of the year.t 
 
 67. M. Volney explains the prevalence of the south-west 
 wind which blows from the Gulf of Mexico, in the follow- 
 ing manner. He supposes that the tropical trade wind is 
 
 * It is not often that the mercury falls so low in the United States ; frequently 
 it does not fall as low as zero in the middle states so that we have presented 
 rather the extreme range of temperature, than the general character of the 
 climate. 
 
 t The cold damp atmosphere which often prevails during- spring and summer 
 in the Atlantic states of America, accompanied by north-easterly winds, is doubt- 
 less attributable to the influence of an unusual quantity of floating ice, off the 
 coast of Labrador and Newfoundland, which condenses the vapor of the ocean, 
 producing mist and fog on the north-eastern coast. During its continuance, it 
 checks perspiration, and causes a general sensation of oppression, head-ache, and 
 torpor of the system, physical and intellectual. In advancing south-westward, 
 it deposits its moisture, and becomes comparatively dry and pleasant, in the 
 valleys of Ohio and the Mississippi, which are screened by the Alleghany moun 
 tains, except during the winter months, when, from its greater strength, it 
 advances across the mountains, and "covers the western country with snow," 01 
 deluges it with rain, for one, two, or three days in succession, reaching as fai 
 as Mississippi, and Louisiana. 
 

 TERRESTRIAL MAGNETISM. 79 
 
 deflected by the Andes of Mexico, and turned from its west- 
 ern course up the valley of the Mississippi that during spring 
 and summer, it advances as far as Montreal and Quebec, and 
 crosses the Alleghanies to the north-east." A circumstance 
 which powerfully contributes to the strength and prevalence of 
 this wind, is the greater rarefaction of the atmosphere over 
 the heated land, than over the ocean during six months of the 
 year, which alone would cause a wind from the ocean during 
 the warm months. It is the meeting of this wind charged 
 with vapor, with the colder north-east current, especially 
 during autumn, which causes vast precipitations of rain, 
 extensive vacuums, water spouts, whirlwinds, and hurricanes, 
 which infest the Gulf of Mexico, and the southern portions 
 of the United States. There can be no doubt, that the meet- 
 ing of these winds, often produces a gyratory or vertiginous 
 motion of the atmosphere, as described by Mr. Redfield.* 
 
 68. We should not overlook the effect of the caloric which 
 is given out during aerial condensations, in producing local 
 rarefactions of the atmosphere, which are always accompa- 
 nied by wind, and a depression of the barometer. Such winds 
 are often attended by precipitation, but not always so that 
 the barometer is not so much an index in regard to rain as to 
 wind. Whenever it sinks low, we may be sure of a gale, 
 though not always of rain. 
 
 69. Are not our hurricanes, which often run in narrow 
 veins, and move with a velocity of from 100 to 120 
 miles per hour, caused by the sudden condensation of a 
 mass of atmospheric vapor, by which a vacuum is produced, 
 as it passes from the aerial to the aqueous state, so that the 
 
 * See American Journal of Science, April, 1831. 
 

 80 A NEW THEORY OF 
 
 surrounding vapor rushes in with great force to restore the 
 equilibrium? It is now generally conceded by those who 
 know any thing about meteorology, that the aqueous vapor 
 which floats above us, constitutes a distinct aerial medium 
 from common atmospheric air that it " percolates the latter 
 mechanically, as water does a sponge :"* from which it may be 
 inferred, that when the volume of aqueous vapor is diminished 
 more than a thousand fold by giving out its caloric, the 
 surrounding vapor rushes in to restore the equilibrium with 
 a force proportioned to its elasticity, causing whirlwinds, 
 tornadoes, &c. 
 
 70. In the valley of Ohio, at Cincinnatti, latitude 39 06', 
 the western winds prevail over eastern, in the proportion of 
 six hundred and thirty-one, to three hundred and twenty-five. 
 At New York, in the proportion of five hundred and eighty, 
 to two hundred and seventy nine. The western winds almost 
 always bring fair weather, if they continue any length of 
 time while the eastern and southern winds, coming from 
 the ocean, generally bring rain. 
 
 71. Mr. Darby has collected a vast number of observations 
 made in different parts of the United States, for the purpose of 
 proving, that the climate is both colder and hotter west, than 
 east of the Alleghany mountains. With the exception of 
 the elevated portions of New York, and the New Eng- 
 land states, which are excessively cold during winter, 
 he has clearly established his position. He has shown that 
 the live oak (quercus semper virens,) grows as far north as 
 34 on the Atlantic slope, while in the central basin of the 
 Mississippi, in Louisiana, it extends only to 30 Q 22' north 
 
 * Daniell on the Atmosphere. 
 
TERRESTRIAL MAGNETISM. 81 
 
 that the same is true of the large and dwarf palms. The sugar 
 cane and orange, which cannot be cultivated to advantage 
 above thirty degrees north in Louisiana, succeed well in South 
 Carolina, Georgia, and Florida, three degrees further north. 
 He also states, that in January 1812, snow fell at Opelousas, 
 latitude 30i, to a depth of eleven inches and that in the latter 
 part of December, 1814, the ponds and lagoons around 
 New Orleans were frozen so as to admit half-grown boys to 
 skate on the ice. ( View of the United States.) 
 
 72. The vicinity of the Atlantic states to the ocean and to 
 the gulf stream, moderates the severity of winter. The 
 Alleghany mountains also protect them from the north and 
 north-west winds. The expectation of many persons that the 
 climate of the United States and of Canada, will be moderated 
 by the removal of forest trees, is entirely fallacious ; which is 
 proved by the intolerable coldness of the western prairies. 
 During winter, and the prevalence of north-west winds from 
 the icy summits of the lofty Chippewayans, and the elevated 
 table land which borders their eastern base, they are exposed to 
 Siberian rigors. Nor have they any mountain barrier to pro- 
 tect them from the northern winds which blow from the mag- 
 netic pole over Hudson's Bay, New Britain, and the Canadas. 
 
 73. After a careful examination of all the facts and argu- 
 ments, we have come to the conclusion, that though the 
 extremes of heat and cold are greater west, than east of the 
 Alleghanies, there is more mild, clear, and agreeable weather 
 in the Mississippi valley than in the Atlantic states. 
 
 74. We have frequently known the south-west winds to 
 prevail in Kentucky, until the middle of December and some- 
 times until Christmas, the weather is bland and delightful. 
 
 11 
 
82 A NEW THEORY OF 
 
 Nothing can exceed the soothing and gorgeous splendor of the 
 autumnal sky, throughout the Mississippi and Ohio valleys. 
 75. We have just received accounts from Captain Nye, com- 
 mander of the Liverpool packet ship York, that, on the 9th of 
 June, 1833, a great number of icebergs were seen in latitude 
 43 N. and from longitude 47 to 49 W. The thermometer 
 has also been unusually low at New York, from the 12th of 
 May until the 12th of June ; averaging about sixty-eight 
 degrees. The same low temperature prevailed the preced- 
 ing May and June; owing to the same cause. A great 
 number of vessels have been lost, at different periods, by being 
 driven against icebergs, on their passage to Quebec, and in 
 going to, and returning from Europe to our own ports. 
 
 76. The cholera first made its appearance at Quebec in 
 May, 1832, and arrived at New York about the 27th of June. 
 It is an important query in relation to this epidemic, how far 
 its character was determined by the thermometric and hygro- 
 metric states of the atmosphere. M. Jannechen, of Moscow, 
 in a work which he published on Cholera, states, " that its in- 
 tensity in Russia was in a direct ratio to the hygrometric state 
 of the atmosphere." This is what we should expect in all 
 gastric and enteritic irritations. Whatever checks cutaneous 
 perspiration, and causes a centripital determination of the 
 fluids, must favor the energy of internal irritations. And 
 whenever a state of the atmosphere exists which favors an 
 unusual flow of cutaneous perspiration, the type of whatever 
 diseases then prevail, must be modified by the general ther- 
 mometric and hygrometric constitution of the season. Does 
 this not explain the prevalence of what has been termed the 
 sweating sickness in England? When the cutaneous exha- 
 
TERRESTRIAL MAGNETISM. 83 
 
 lents have been in a medium state of excitement, fever is pro- 
 duced by exposure to malaria, hot sun, and night air. If the 
 malaria be mild, intermittents and remittents follow ; if viru- 
 lent, malignant, or yellow fever, malignant cholera, or dysen- 
 tery, according to the previous thermometric and hygrometric 
 state of the atmosphere. We hope to be able at some future 
 period, to examine this subject more at large. 
 
 77. We have seen, that the cause of unequal seasons 
 in the middle latitudes, is owing to the greater or less accu- 
 mulation of ice in the northern seas. When they are open, 
 the polar winds are tempered by passing over them, and we 
 have mild winters ; but when they are filled with accumulated 
 icebergs, and covered with field ice to a great extent, the 
 
 ^winds pass to the lower latitudes with slight mitigation of 
 severity, causing excessive winters. This is the true ration- 
 ale of onr unequal winters. They are not owing to the 
 operation of distant planetary and cometary influence, but to 
 the relative position of land and sea in the northern latitudes, 
 and to the occasional obstructions of the Arctic ice in Davis' 
 Straits, Baffin's Bay, and the Greenland Sea, by which it be- 
 comes greatly accumulated, until the unequal expansion of 
 the upper and lower portions of ice, by the sun's rays, causes 
 it to rend in a thousand fragments, when the waves of the 
 ocean complete its final disruption, and it is . carried by cur- 
 rents into lower latitudes and dissolved. Thus, Infinite Wis- 
 dom has provided, that extremes shall never long prevail. 
 The order of nature presents a beautiful 'system of checks 
 and balances, by which every evil incident to her economy, 
 brings with it its own remedy. 
 
 78. We have thus explained in the most simple manner, 
 
84 A NEW THEQRY OF 
 
 the strange variations of the Arctic climate, and shown how 
 they modify the temperature of lower latitudes sometimes 
 causing mild winters, at other times excessive winters. We 
 shall next examine the connection of these changes with the 
 variations of the magnetic needle. 
 
 79. We have already stated, that if the whole earth con- 
 sisted of a uniform surface, there would be but two magnetic 
 poles, and that they would be the poles of the earth's axis : 
 moreover, that the needle would be every where directed to 
 these poles, and that there would be no variation of the com- 
 pass. We stated further, that in the above condition of our 
 planet, a magnetic needle perfectly balanced on its centre, 
 would continue to dtp uniformly, in advancing from the mag- 
 netic equator to the poles, where it would be vertical ; and 
 that the horizontal intensity would decrease uniformly on all 
 meridians, from the magnetic equator, which woultf coincide 
 with the geographical equator, to the poles, where it would be 
 nothing. 
 
 80. If the above positions be correct, we perceive at once, 
 that all the irregularities attending the dip, variation, and 
 intensity of the needle, are occasioned by the unequal distri- 
 bution of terrestrial temperature, which is caused by the une- 
 qual distribution of land and water, and by unequal accumu- 
 lations of ice in the polar seas. 
 
 81. Many strange and improbable hypotheses have been 
 invented by philosophers, to account for the progressive varia- 
 tion of the magnetic needle, the most prominent of which is 
 that of Dr. Halley ; and which has been embraced with some 
 modifications, by M. Hansteen, of Norway. 
 
 82. Dr. Halley supposed the earth we inhabit to be a 
 
TERRESTRIAL MAGNETISM. 85 ! 
 
 mere external shell, enclosing towards its centre, a detached 
 magnetic nucleus of a spherical shape, which he termed a 
 terrella, and which he imagined was about 1150 miles in dia- 
 meter ; that it revolved with the external shell on a simi- 
 lar axis, but with a less velocity. He supposed both these 
 spheres to be magnets, having each two poles ; but the poles 
 of the one, not corresponding in situation with the poles of the 
 other.* The difference of the periods of rotation of the two 
 spheres, he conceived to be very small, yet sufficient to become 
 sensible after the lapse of years, and to occasion a change in 
 the relative situation of the two poles ; hence would arise 
 changes in the directions of their resulting actions, and cor- 
 responding changes in the variation of the magnetic needle. 
 (See Library of Useful Knowledge.) 
 
 83. M. Hansteen's theory coincides 1 with that of Dr. Halley 
 so far as this, that he maintained the existence of two mag- 
 netic poles in each hemisphere, within the earth, and that 
 they revolve round the terrestrial poles, though in unequal 
 periods of time. 
 
 84. We shall endeavor to show that there is no proof of a 
 revolutionary movement of the magnetic poles, except their 
 shifting a few degrees from east to west, or from west to east 
 and that in reality, such a movement is just as impossible as 
 the revolutionary movement of the " cold meridians" of Dr. 
 Brewster. The American pole has been nearly stationary for 
 the last forty-five years ; but with a slight shifting to the west- 
 ward, within the last thirty years. We have no evidence that 
 it has shifted more than five or six degrees within the last 
 hundred and fifty years ; nor that the eastern south pole has 
 shifted to the same extent in the same time. How is it possi- 
 ble that any philosopher should contend, that the centres of 
 
86 A NEW THEORY OP 
 
 maximum cold of the American continent passed over to Eu- 
 rope eighteen or nineteen centuries ago, without a corresponding 
 shifting of the land and sea? But we have no evidence, that 
 any material alteration has taken place, in the relative posi- 
 tion of land and sea for several thousand years. Hence, the 
 cold meridians of the northern hemisphere, must have 
 remained where they now are for indefinite periods of past 
 time; and must continue to occupy their continental posi- 
 tions, until in the progress of geological revolutions, the pre- 
 sent continents shall disappear, and others arise, to restore the 
 balance of nature. 
 
 85. We have shown, that extraordinary accumulations 
 of ice in the outlets of the polar seas, are sufficient to account 
 for the existence of a minor focus of cold, the influence of which 
 might extend throughout a great portion of America and Eu- 
 rope, and lower their temperature as in the epoch of the Caesars. 
 It is a remarkable- coincidence, in perfect accordance with our 
 theory, that at London and Paris, the magnetic needle was 
 directed towards Spitzbergen, about midway between the 
 American and Asiatic poles, during the period of greatest 
 accumulation of ice in the Greenland Sea, when the Norwe- 
 gian and Iceland colonies were cut off from Europe, and 
 when the vine ceased to flourish in England ; while at the 
 same time, over the great continents o'f Asia and America, it 
 pointed to their respective magnetic poles as at present : the 
 plain inference from which, is, that there must have been ano- 
 ther pole at that time, near the meridian of London and Spitz- 
 bergen, which has since disappeared, as the Greenland Sea 
 became open. 
 
 86. There are strong reasons for believing, that there is 
 now more than one magnetic pole in the north of Asia, as M. 
 
TERRESTRIAL MAGNETISM, 87 
 
 Biot describes two lines of no variation on the eastern conti- 
 nent ; one on the meridian of Nova Zembla, and the other 
 passing through the north-east of Siberia. No observations 
 have been made by which we can determine the exact position 
 of any of the magnetic poles, except those of Captain Parry 
 in 1819 and 1820, when he passed a few degrees west of the 
 American pole on the 8th of August, in Prince Regent's In- 
 let, latitude 72, where the directive power of his compass 
 needles ceased, remaining in whatever position they were 
 placed. Captain Parry took no observation of the dipping 
 needle there, but rightly supposes " that the dip would have 
 been greater than at Winter Harbor," where it was 88 Q 43.' 
 
 87. Dr. Gilbert published a very ingenious work on mag- . 
 netism, in the year 1590, in which he maintained, that the 
 earth contained within itself a huge magnet, lying in a direc- 
 tion nearly coinciding with its axis of rotation, and that its 
 power was collected at the poles of the earth. It is said that 
 Kepler ranked this hypothesis among the greatest discoveries 
 in the annals of science. (See Lib. of U. Knowledge, 
 Article Magnetism.} 
 
 88. The progressive and irregular changes which the varia- 
 tion and dip have undergone at different periods, and which 
 had not been much observed at the time of Dr. Gilbert, totally 
 preclude the idea of permanently fixed depots of magnetic 
 attraction. It must be conceded, however, that in some re- 
 spects, the earth acts as a great magnet ; inasmuch as it 
 imparts magnetism to substances placed in the direction of the 
 magnetic meridian ; and because it attracts the dipping needle 
 towards its centre, when placed at right angles to the mag- 
 netic meridian, so as not to be influenced by the horizontal 
 force. Allowing that iron is necessary to the production of 
 

 88 A NEW THEORY OF 
 
 magnetism, which is not the fact, it is distributed in vast 
 quantities throughout the earth as far as we can discover.* 
 But that there are grand depots of magnetic iron in the polar 
 regions, we have not the slightest evidence for believing. Ne- 
 vertheless, this hypothesis has swayed the opinions of philo- 
 sophers from the days of Gilbert to the present time and 
 has been a perpetual source of error among writers on mag- 
 netism, who seem to have taken it for granted, that the inten- 
 sity of magnetic attraction increases from the magnetic equator 
 to the poles. 
 
 89. An amusing example of the general prevalence of this 
 belief among common seamen, is related by Barrington. In 
 the year 1754, Captain Wilson commanded the Sea Nymph, a 
 Greenland whale ship, when at the latter end of June, they 
 sailed through floating ice from 74 to 81 north, but having 
 then proceeded beyond the ice, they pursued the whales to 
 latitude 82 15, where the sea was open as far as they 
 could distinguish. Both Captain Wilson and Mr. Ware, the 
 mate, had a strong desire to push forward towards the pole ; 
 on hearing which, the common sailors remonstrated, saying, 
 " that if they should be able to proceed so far, the ship would 
 fall into pieces, as the pole would draw all the iron work out 
 of her," which caused the captain to relinquish his design. 
 We have adverted to this circumstance for the purpose of 
 showing how the great -mass of mankind, philosophers not 
 excepted, imperceptibly follow the footsteps of their predeces- 
 sors, frequently without knowing why. A slight examination 
 of facts will show, that the above doctrine has no foundation 
 in truth that in reality, the directive power of the magnetic 
 needle diminishes as we approach the poles. 
 
 * Probably one fifteenth of the entire globe consists of iron. 
 
TERRESTRIAL MAGNETISM. 89 
 
 90. It is to be regretted that such men as Count Humboldt 
 and Captain Sabine, should have contributed to the propaga- 
 tion of this error. Humboldt supposed, that the magnetic 
 intensity increased from the magnetic equator to the poles, 
 because his compass needle performed a greater number of 
 oscillations at Paris in a given time than at Peru ;* notwith- 
 standing the same needle performed an equal number of 
 oscillations at Mexico, 7,400 feet above the sea, that it did at 
 Peru ; which ought to have convinced him, that the mag- 
 netic intensity did not increase from the magnetic equator to 
 the poles. 
 
 91. Captain Sabine seems to have concluded that the mag- 
 netic intensity increases in going towards the pole, because 
 the dipping needle performed a greater number of oscillations 
 in Baffin's Bay and Davis' Straits than at London. We be- 
 fore suggested, that this was owing to the diminished inten- 
 sity of the horizontal force, which in lower latitudes, coun- 
 teracts the vertical force. Captain Sabine's experiments are 
 inconclusive, as they were not fairly accompanied by obser- 
 vations in the same latitude with a horizontal needle. 
 
 92. There is. an overwhelming mass of testimony in direct 
 opposition to the conclusions of Humboldt and Sabine, fur- 
 nished by hundreds of seamen arid other individuals, who 
 had no speculative views to sustain ; and established by a 
 long course of experiments by M. Hansteen, Captain Scoresby, 
 and many other accurate observers. The most conclusive 
 series of experiments ever performed to determine the mag- 
 netic intensity, is exhibited by M. Hansteen in the following 
 
 * If the observation was made, on the Cordilleras, ten or twelve thousand feet 
 above the sea, we should expect a considerable diminution of magnetic power. 
 12 
 
90 A NEW THEORY OF , . 
 
 tables ; taken from the Edinburgh Journal of Science, volume 
 IV., 'April, 1826; showing the time required for a compass 
 needle to make 300 oscillations. We have also presented Dr. 
 Brewster's explanation of M. Hansteen's tables, showing the 
 intensity of the magnetic force in different parts of the earth's 
 surface. " In order to determine the intensity of magnetism at 
 different places, and consequently the direction of what he 
 calls the isodynamical magnetic lines, or the magnetic lines 
 of equal intensity, he had a magnetic needle of a cylindrical 
 form, constructed with great care. This needle he entrusted to 
 various philosophers, who counted the time in which three 
 hundred horizontal oscillations were performed, in various 
 parts of Norway, Sweden, Denmark, Prussia, Holland, 
 France, England, and Scotland.. The greater number of 
 these were made by Professor Hansteen himself, many of 
 them by M. Naumann, several by M. Erichsen, and a con- 
 siderable number by Professor Oerstedt, of Copenhagen, when 
 he was travelling in England in 1823. Those which were 
 made by this last philosopher in Edinburgh, on the 4th July, 
 and at which we had the pleasure of assisting, were performed 
 in the field behind Coates Crescent, and nearly at the inter- 
 section of Walker Street and Melville Street. These possess 
 considerable interest, as being the most westerly of all that 
 have yet been made. 
 
 " The following table contains the result of these observa- 
 tions, the first and second columns containing the latitude of 
 the place of observation, and its longitude from Ferroe ; and 
 the third the number of seconds in which 300 oscillations are 
 performed by the suspended needle." 
 
TERRESTRIAL MAGNETISM. 
 
 PLACES. 
 
 Lat. 
 
 Long, 
 from 
 Ferroe. 
 
 Time of 
 300 Oscilla- 
 tions. 
 
 Berlin 
 
 _ 
 
 52 
 
 32' 
 
 31 2' 
 
 760".03 
 
 Paris 
 
 _ 
 
 48 
 
 50 
 
 20 
 
 753.03 
 
 London 
 
 . 
 
 51 
 
 31 
 
 17 34 
 
 775.34 
 
 Edinburgh - 
 
 " 1 
 
 55 
 
 58 
 
 14 29 
 
 820.26 
 
 Liverpool 
 
 .' * 1 
 
 53 
 
 22 
 
 14 43 
 
 801.6 
 
 Oxford 
 
 . 
 
 51 
 
 46 
 
 16 24 
 
 779.8 
 
 Christiansand 
 
 . 
 
 58 
 
 8 
 
 25 43 
 
 820.3 
 
 Mandal 
 
 . 
 
 58 
 
 1 
 
 25 9 
 
 814.3 
 
 Tjos 
 
 - 
 
 
 
 
 816.3 
 
 Carlscrona 
 
 . 
 
 56 
 
 7. 
 
 33 13 
 
 785.3 
 
 Ystad 
 
 _ 
 
 55 
 
 26 
 
 31 28 
 
 779.3 
 
 Szrim 
 
 - 
 
 52 
 
 7 
 
 34 48 
 
 748.1 . 
 
 Glogau 
 
 - 
 
 51 
 
 43 
 
 33 36 
 
 748.8 
 
 Carolath 
 
 _ 
 
 51 
 
 46 
 
 33 37 
 
 752.7 
 
 Zelgos 
 
 - 
 
 53 
 
 11 
 
 32 48 
 
 759.7 
 
 Danzig 
 
 - 
 
 54 
 
 21 
 
 36 18 
 
 770.4 
 
 Marie nburgh 
 
 
 
 54 ' 
 
 2 
 
 36 42 
 
 766.0 * 
 
 Goslina 
 
 . 
 
 52 
 
 34 
 
 34 43 
 
 759.7 
 
 Aiistrin - 
 
 * 
 
 52 
 
 35 
 
 32 40 
 
 762.4 * 
 
 Christiana 
 
 _ 
 
 59 
 
 55 
 
 28 25 
 
 814.76 
 
 Friedrichshall 
 
 1819 
 
 59 
 
 8 
 
 29 4 
 
 821.7 * 
 
 
 1822 
 
 
 
 
 830.3 
 
 Q,uistrum 
 
 1819 
 
 58 
 
 27 
 
 29 25 
 
 816.1 * 
 
 
 1820 
 
 
 
 
 815.4 
 
 Hede 
 
 . 
 
 57 
 
 58 
 
 29 48 
 
 810.8 * 
 
 Gothenburg 
 
 1819 
 
 57 
 
 42 
 
 29 38 
 
 812.2 * 
 
 
 1820 
 
 
 
 
 812.1 
 
 Uuibille 
 
 - 
 
 56 
 
 47 
 
 30 30 
 
 791.6 * 
 
 Helsingburg 
 
 1820 
 
 56 
 
 3 
 
 30 23 
 
 791.1 * 
 
 
 1820 
 
 
 
 
 790.0 * 
 
 Helfingoer 
 
 1820 
 
 56 
 
 2 
 
 30 18 
 
 789.8 * 
 
 
 1820 
 
 
 
 
 784.6 * 
 
 Copenhagen 
 
 - 
 
 55 
 
 41 
 
 30 15 
 
 788.08 
 
 Friedrichsburg 
 
 - 
 
 55 
 
 56 
 
 29 58 
 
 785.9 
 
 Soroe 
 
 1820 
 
 55 
 
 27 
 
 29 14 
 
 790.6 
 
 
 1822 
 
 
 
 
 790.4 
 
 Skieberg 
 
 - 
 
 59 
 
 14 
 
 28 51 
 
 826.7 
 
 Kongsberg 
 
 1820 
 
 59 
 
 40 
 
 27 20 
 
 845.4 
 
 
 1821 
 
 
 
 
 839.3 
 
 
 
 
 
 
 845.1 
 
A NEW THEORY OP 
 
 PLACES. 
 
 Lat. 
 
 Long, 
 from 
 Ferroe. 
 
 Time of 
 300 Oscilla- 
 tions. 
 
 
 
 
 837".8 
 
 1821 
 
 
 
 859.5 
 
 Bolkesjo 
 
 59 43' 
 
 27 OO/ 
 
 834.9 
 
 Vik 
 
 
 
 836.8 
 
 Tindosen 
 
 
 
 834.6 
 
 Oernas 
 
 
 
 829.1 
 
 Ingolfsland - 
 
 59 53 
 
 26 28 
 
 833.4 
 
 Miland 
 
 59 56 
 
 26 36 
 
 833.4 
 
 Tind 
 
 60 00 
 
 
 835.7 
 
 Midboen 
 
 
 
 836.8 
 
 Rogsland 
 
 
 
 838.0 
 
 Norsteboe 
 
 60 20 
 
 26 17 
 
 839.8 
 
 Holmekjarn - 
 
 60 17 
 
 25 24 
 
 832.8 
 
 Maursater 
 
 60 25 
 
 25 3 
 
 829.3 
 
 Eifjord 
 
 
 
 852.6 
 
 Ullensvang - 
 
 60 20 
 
 24 18 
 
 840.7 
 
 Johnnas-Tangen 
 
 
 
 
 843.8 
 
 Gjermundshafen 
 
 60 3 
 
 23 52 
 
 846.2 
 
 Kaarevigen - 
 
 59 45 
 
 23 7 
 
 838.2 
 
 Findaas 
 
 59 45 
 
 22 54 
 
 861.7 
 
 Siggens - 
 
 
 
 824.2 
 
 
 
 
 
 837.4 
 
 Folgeroe 
 
 59 48 
 
 22 56 
 
 835.9 
 
 Engesund 
 
 59 55 
 
 22 53 
 
 840.7 . 
 
 Bekkervig 
 
 60 1 
 
 22 50 
 
 851.0 
 
 Bratholmen - 
 
 60 21 
 
 22 47 
 
 839.5 
 
 Bergen 
 
 
 
 
 Fort Friedrichsberg 
 
 60 24 
 
 22 57 
 
 850.1 
 
 Friedrichsberg 
 Lunggaards. See 
 
 
 
 850.5 
 849.3 
 
 Lyderhoru, 1255 feet 
 
 
 
 843.7 
 
 Lovstakken, 1524 
 
 
 
 
 feet 
 
 
 
 904.7 
 
 Haugs 
 
 60 27 
 
 23 18 
 
 845.2 
 
 Bolstadoren - 
 
 60 32 
 
 23 43 
 
 847.7 
 
 Evanger 
 
 60 33 
 
 23 52 
 
 845.9 
 
 Vossevangen 
 
 60 38 
 
 24 10 
 
 850.6 
 
 Tvinde 
 
 60 42 
 
 24 11 
 
 849.1 
 
 Staleim 
 
 60 52 
 
 24 19 
 
 848.9 
 
 Leirdafeoren 
 
 61 10 
 
 25 29 
 
 856.3 
 
TERRESTRIAL MAGNETISM. 
 
 PLACES. 
 
 Lat. 
 
 Long, 
 from 
 Ferroe. 
 
 Time of 
 300 Oscilla- 
 tions. 
 
 Leirdals 
 
 61 
 
 8' 
 
 25 30' 
 
 852".2 
 
 Maristuen 
 
 61 
 
 2 
 
 25 54 
 
 855.3 
 
 Nyestuen 
 
 61 
 
 8 
 
 25 59 
 
 853.2 
 
 Vangs 
 
 61 
 
 6 
 
 26 23 
 
 845.6 
 
 Slidre 
 
 61 
 
 5 
 
 26 49 
 
 853.9 
 
 Tumlevold 
 
 60 
 
 51 
 
 27 38 
 
 843.7 
 
 Grans 
 
 60 
 
 22 
 
 28 12 
 
 842.3 
 
 Moe 
 
 60 
 
 14 
 
 28 11 
 
 848.3 
 
 Sundvold j- ~ 
 
 60 
 
 4 
 
 28 7 
 
 842.6 
 
 Johnsrud 
 
 59 
 
 57 
 
 28 19 
 
 841.5 
 
 Hurdal 
 
 60 
 
 26 
 
 28 49 
 
 827.3 
 
 Trogstad 
 
 60 
 
 8 
 
 28 56 
 
 823.8 
 
 Sunbye 1822 
 
 59 
 
 36 
 
 28 35 
 
 826.8 
 
 Sooner 
 
 59 
 
 32 
 
 28 25 
 
 827.8 
 
 
 
 
 
 828.1 
 
 Boe 
 
 59 
 
 7 
 
 29 7 
 
 823.2 
 
 Altorp 
 
 58 
 
 53 
 
 29 54 
 
 816.3 
 
 Oedskjolds-Moen 
 
 58 
 
 50 
 
 29 52 
 
 816.0 
 
 Elleoen - - 
 
 59 
 
 19 
 
 28 20 
 
 826.7 
 
 Godtskjar 
 
 57 
 
 26 
 
 29 43 
 
 809.9 
 
 Korset 
 
 58 
 
 49 
 
 27 12 
 
 824.5 
 
 Helgeraae 
 
 58 
 
 59 
 
 27 34 
 
 822.7 
 
 Stubberud t - 
 
 59 
 
 4 
 
 27 55 
 
 818.9 
 
 Solerud 
 
 59 
 
 21 
 
 28 9 
 
 826.5 
 
 Konnerud-Kollen 
 
 
 
 
 
 1823 
 
 
 
 
 875.5 
 
 Auestad 
 
 59 
 
 49 
 
 27 53 
 
 852.1 
 
 Bragernas 
 
 59 
 
 49 
 
 27 53 
 
 848.6 
 
 Ravnsborg - 
 
 59 
 
 52 
 
 28 17 
 
 820.5 * 
 
 Friedrichsvarn 1824 
 
 59 
 
 
 
 27 44 
 
 813.5 
 
 Friedrichshavn 
 
 57 
 
 27 
 
 28 13 
 
 808.1 
 
 Aalborg 
 
 57 
 
 3 
 
 27 36 
 
 806.0 
 
 Sporring 
 
 
 
 
 799.9 
 
 Aarhuns 
 
 56 
 
 10 
 
 27 54 
 
 796.0 
 
 Hovedkrug - 
 
 
 
 
 798.3 
 
 Weile 
 
 55 
 
 43 
 
 27 12 
 
 793.9 
 
 Apenrade 
 
 55 
 
 3 
 
 27 6 
 
 786.4 
 
 Gehlau 
 
 
 
 
 787.9 
 
 Schleswig 
 
 54 
 
 31 
 
 27 15 
 
 783.0 
 
 
 
 
 
 785.5 
 
94 
 
 A NEW THEORY OF 
 
 PLACES. 
 
 Lat. 
 
 Long, 
 from 
 Ferroe. 
 
 Time of 
 300 Oscilla- 
 tions. 
 
 Remmels 
 
 54* r 
 
 27 18/ 
 
 783".0 
 
 Elmshorn 
 
 53 46 
 
 27 18 
 
 779.1 
 
 Altona 
 
 53 33 
 
 27 33 
 
 776.1 
 
 
 
 
 774.9 
 
 Berlin 
 
 52 32 
 
 31 2 
 
 760.4 
 
 
 
 
 759.9 
 
 Liibeck 
 
 53 51 
 
 28 21 
 
 776.2 
 
 Ploen 
 
 54 9 
 
 28 6 
 
 780.5 
 
 Preetz 
 
 54 13 
 
 27 57 
 
 779.0 
 
 Kolding 
 
 55 27 
 
 27 
 
 789.1 
 
 Odense 
 
 55 24 
 
 27 59 
 
 793.7 
 
 Buskerud 
 
 
 
 845.5 
 
 Johnsknuden 
 
 
 
 961.3 
 
 Skrimfjeld 
 
 
 
 891.3 
 
 Rolloug 
 
 59 59 
 
 27 5 
 
 844.0 
 
 Synhovedet - 
 
 
 
 846.3 
 
 Eje 
 
 60 6 
 
 26 53 
 
 838.5 
 
 Ejesfjeld 
 
 
 
 831.2 
 
 Daglio 
 
 60 18 
 
 26 26 
 
 837.4 
 
 Torpe 
 
 60 40 
 
 26 47 
 
 841.5 
 
 Haavi Juni 
 
 61 7 
 
 26 42 
 
 851.2 
 
 Sept. 
 
 
 
 850.4 
 
 Urland 
 
 61 
 
 24 55 
 
 849.2 
 
 Voss Juni 
 
 60 38 
 
 24 10 
 
 856.5 
 
 Sept. 
 
 
 
 845.9 
 
 Age-Nuten - 
 
 
 
 842.7 
 
 Vigor 
 
 60 18 
 
 24 5 
 
 850.7 
 
 Bergen 
 
 60 24 
 
 22 57 
 
 
 Nyegaard - 
 
 
 
 857.1 
 
 Floifjeldet 
 
 
 
 854.7 
 
 Lovstakken 
 
 
 
 844.2 
 
 Friedrichsberg 
 
 
 
 851.7 
 
 Lindaas 
 
 60 43 
 
 23 8 
 
 843.5 
 
 Evenvig 
 
 60 58 
 
 23 8 
 
 850.6 
 
 Yttre-Sulen - 
 
 61 4 
 
 22 45 
 
 852.1 
 
 Stensund 
 
 61 3 
 
 22 52 
 
 852.9 
 
 Pollefjeld - 
 
 
 
 861.8 
 
 Askevold 
 
 61 24 
 
 23 7 
 
 861.1 
 
 Vilnas 
 
 61 22 
 
 22 58 
 
 860.7 
 
 Sougesund 
 
 61 22 
 
 23 11 
 
 861.7 
 
TERRESTRIAL MAGNETISM. 
 
 PLACES. 
 
 Lat. 
 
 Long, 
 from 
 Ferroe. 
 
 Time of 
 300 Oscilla- 
 tions. 
 
 Alden 
 
 61 22' 
 
 22 50' 
 
 850".7 
 
 Bueland 
 
 61 17 
 
 22 44 
 
 851.2 
 
 Sveen 
 
 
 
 856.4 
 
 Q,uamshest - 
 
 
 
 849.8 
 
 Forde Juli 
 
 61 32 
 
 23 48 
 
 858.9 
 
 Aug. 
 
 
 
 858.8 
 
 Jolster 
 
 61 35 
 
 24 10 
 
 848.6 
 
 Gloppen 
 
 61 51 
 
 24 6 
 
 861.9 
 
 Indvig 
 
 61 49 
 
 24 34 
 
 860.4 
 
 Horningdal - 
 
 61 59 
 
 24 33 
 
 862.6 
 
 Halsylta 
 
 62 7 
 
 24 54 
 
 864.8 
 
 Nordal 
 
 62 18 
 
 25 13 
 
 870.3 
 
 Veblungsnas 
 
 62 31 
 
 25 39 
 
 868.3 
 
 Fladmark 
 
 
 
 862.9 
 
 Nyestuen 
 
 
 
 862.7 
 
 Fogstuen 
 
 62 5 
 
 27 9 
 
 856.9 
 
 Jerkin 
 
 62 12 
 
 27 29 
 
 846.5 
 
 Foldal 
 
 62 7 
 
 27 57 
 
 855.5 
 
 Kongsvold 
 
 62 18 
 
 27 36 
 
 860.0 
 
 Drivstuen 
 
 62 26 
 
 27 41 
 
 858.0 
 
 Riise 
 
 62 31 
 
 27 41 
 
 858.1 
 
 
 
 
 859.8 
 
 Naverdal 
 
 62 42 
 
 28 6 
 
 858.7 
 
 Stoa 
 
 62 32 
 
 28 21 
 
 860.4 
 
 Gora 
 
 62 35 
 
 27 2 
 
 862.1 
 
 Tofte 
 
 61 58 
 
 27 10 
 
 859.3 
 
 Vauge 
 
 61 51 
 
 27 4 
 
 860.8 
 
 Vinje 
 
 60 52 
 
 24 22 
 
 848.2 
 
 Nyestuen 
 
 61 8 
 
 25 59 
 
 852.1- 
 
 Skougstad 
 
 61 10 
 
 26 12 
 
 853.7 
 
 Smedshammer 
 
 60 29 
 
 28 14 
 
 841.9 
 
 Sundvold 
 
 60 4 
 
 28 7 
 
 839.2 
 
 93. It will be evident to the reflecting reader, that these 
 tables are incomplete, from the want of another column, 
 giving the elevations above. the sea at the respective places of 
 observation. 
 
96 A NEW THEORY OF 
 
 94. It would have been much more satisfactory, could we 
 have presented similar tables, showing the different intensities 
 of the needle in different latitudes of the American continent. 
 The principle to be illustrated, however, is equally proved, by 
 observations made in any quarter of the globe. 
 
 95. It is a matter of almost universal notoriety among sea- 
 men, that the compass needle becomes sluggish in high lati- 
 tudes that its directive power is so weak, as to be greatly 
 influenced by the local attraction of the ship's iron, which sel- 
 dom occurs to any considerable extent in lower and warmer 
 latitudes ; while at the magnetic pole it is nothing, the needle 
 remaining in whatever direction it is placed, as was proved by 
 Sir William E. Parry in the summer of 1819 and'1820. It is 
 highly probable, that a dipping needle, placed in the direction of 
 the magnetic meridian, would perform a greater number of 
 oscillations in a given time near the pole than at the magnetic 
 equator for the obvious reason, that the horizontal force is 
 greatly diminished and not because the vertical attraction 
 of the earth is increased. I performed an experiment with a 
 dipping needle which convinced me at once, that the vertical 
 attraction of the needle by the earth is nearly the same in every 
 part of the globe (though I tried it only in New York,) when 
 not cou nteracted by the horizontal force. On placing the needle 
 at right angles with the magnetic meridian, it uniformly be- 
 came vertical^ but when placed in the direction of the mag- 
 netic meridian, always rose about 279 towards the horizontal 
 position. Hence, I concluded that the dipping needle would 
 make an equal number of oscillations in a vertical plane yi 
 all latitudes and longitudes, when not influenced by the 
 
TERRESTRIAL MAGNETISM. 97 
 
 horizontal or directive power, which would be at the magnetic 
 poles and in all latitudes when the needle is turned east 
 and west.* 
 
 96. The dip of the needle increases in proportion as the 
 mean temperature decreases and not in proportion to the 
 increase of distance from the magnetic equator. A few facts ' 
 will illustrate this position. 
 
 97. In 1818, Captain Sabine found the dip 83 08' on the 
 ice in Davis' Strait, in latitude 68 22'; but in 1819-20, he 
 found .the dip 83 4' in latitude 64 00', nearly four degrees 
 farther south in the same strait from which we infer, that 
 the temperature of latitude 64 00' during 1819-20, was 
 about the same as that of 68 22' in 1818. It is highly pro- 
 bable, that the mean annual temperature is nearly the same, 
 viz., about zero, from latitude 68 or 69 to the northern ex- 
 tremity of the continent and from Baffin's Bay, longitude 82 
 10', to longitude 112 or 115 west and that the magnetic 
 needle would be nearly vertical over the whole extent of that 
 desolate region. Such is the result of all the observations which 
 have been made within the last fifteen years. In longitude 
 25 W. and latitude 76 N., where the mean temperature is 
 fifteen degrees higher, Captain Sabine found the dip only 80. 
 At Spitzbergen, nearly 80 N. latitude, he found the dip only 
 81 10' while we have seen, that at Melville Island, in lati- 
 tude 74 30', it was 88 43' and probably two or three 
 degrees farther south, it is 90. It would be a waste of time 
 to multiply examples in proof of a proposition so plain and 
 
 * It has been a matter of great astonishment to me, tkat no account has 
 been given of this simple experiment, in any of the books on magnetism which 
 I have consulted. 
 13 
 
98 A NEW THEORY OF 
 
 obvious. It is highly probable, that the magnetic poles, as 
 well as the magnetic equator, shift a few degrees north and 
 south, as the sun passes from one side of the equinoctial line 
 to the other. 
 
 98. It may be asked, why the northern portion of our 
 continent, where the Rocky Mountains terminate in the Arc- 
 tic Sea, in latitude 70 N. and longitude 135 W., is not colder 
 than Bear Lake, Melville Island, Winter Island, &c., being 
 more elevated. We answer, because it is much nearer to the 
 western coast of the continent, and because all western, coasts 
 are warmer than eastern coasts in the middle and higher lati- 
 tudes, owing to the greater amount of condensation and preci- 
 pitation, by which caloric is given out, as we before explained.* 
 At the mouth of the Mackenzie, the Arctic Sea is quite open 
 during summer while farther east, from longitude 112 W. 
 to Baffin's Bay, for seven hundred miles, the sea and inlets are 
 never clear of ice. In latitude 70 N., the American continent 
 extends from Icy Cape, longitude 165 W., to Davis' Strait, 
 82 30' W. longitude, two thousand miles in width and if 
 we include Greenland, with Baffin's Bay and Davis' Strait, 
 which are nearly always covered with ice, we have a continent 
 more than three thousand miles wide, and extending nearly 
 half around the polar circle. This single fact solves the 
 problem of our excessive winters and explains why the 
 magnetic needle obeys the American pole over two-thirds of 
 the northern hemisphere. 
 
 99. The mean annual temperature of Labrador, in latitude 
 57 P , is 26 42', the mean temperature of winter being about 
 
 * See Section 121, Part I. and Sections 68 and 69, Part II. 
 
 m 
 
TERRESTRIAL MAGNETISM. 99 
 
 zero, nearly on a level with the sea ; while at Enontikies in 
 Iceland, latitude 68 30', and longitude 20 47', the mean an- 
 nual temperature is about 26, from which it is evident, that 
 after leaving the continent, we must advance upwards of ten 
 degrees of latitude northward to find the same temperature in 
 a maritime or insular situation. At North Cape, in Lapland, 
 latitude 71, we find a higher temperature than at Labrador, in 
 latitude 57, the mean being 32 hence we perceive, that the 
 line of mean annual temperature is fourteen degrees higher 
 on the northern coast of Lapland, than at Labrador, owing to 
 the maritime character of its climate. The lines of equal dip 
 of the needle, invariably follow the same laws which govern 
 the isothermal lines. 
 
 400. Humboldt estimates the mean summer temperature of 
 Cumberland House, in latitude 53 57', the same as that of 
 Central Russia, in latitude 58 30', and longitude 36 east. In 
 latitude 47, at Quebec, the mean annual temperature is nearly 
 as low as that of St. Petersburg, in latitude 60. Such are the 
 differences of temperature caused by the relative extent of land 
 and sea. 
 
 101. A writer in the Edinburgh Philosophical Journal, com- 
 menting on the magnetic theory of M. Hansteen, asks, who 
 has been able to explain the cold of Siberia, Greenland, or 
 Terra del Puego ? Who, the strange variations of the polar 
 climate, or Cook's observations on the different distances to 
 which the polar ice extends from the south pole, in the Pacific 
 and Atlantic Oceans ? We trust that these questions have 
 been satisfactorily answered in this essay ; and that future 
 observations will establish our conclusions on the firm basis of 
 positive demonstration. 
 
100 A NEW THEORY OF 
 
 102. A collection of very important facts in relation to the 
 variation of the needle in the United States, has been recently 
 published in the American Journal of Science, by General 
 Schuyler, Mr. De Witt, Mr. George Gillet, and others, which 
 conclusively demonstrate, that the American pole has shifted 
 from east to west, and from west to east, within the last hundred 
 and fifty years. Mr. Gillet gives the western variation at 
 Philadelphia, on the authority of Mr. Scull, as 8 30' in 1701. 
 In 1793, according to the observations of Mr. Brooks, it was 
 1 30', making a difference of seven degrees in ninety-two 
 years. In 1794, the needle was observed to recede westward, 
 according to the observations of Mr. Brooks and Mr. Hum- 
 phreys at Philadelphia ; and by others in Virginia. 
 
 103. About the year 1810, the late Mr. Spencer, of Lifch- 
 field County, published in the Connecticut Courant, that for a 
 number of years then past, the needle had declined to the west. 
 Mr. Nathaniel Goodwin, of Hartford, who has attended to the 
 variation for several years past, states, that the needle has 
 steadily tended to the west. Mr. Gillet states, from* his own 
 observations, that " since 1805, the needle has declined to the 
 west more than a degree." It is impossible to reconcile the 
 above observations with the hypothesis of a revolutionary 
 movement of the American pole j while they are in perfect 
 accordance with the irregular shifting of the pole, caused by 
 unequal accumulations of ice in the Arctic circle at differ- 
 ent periods, as we shall see hereafter. Dr. Bowditch gives the 
 following results of observations made farther north. 
 
 104. " The variation of the magnetic needle, in the vicinity 
 of Boston, has decreased since the first observations were 
 made in this country, at the rate of a degree in thirty or forty 
 
TERRESTRIAL MAGNETISM. 101 
 
 years ; for by the papers published in the first volume of the 
 Memoirs of the American Academy, it was 9 00' west, in the 
 year 17088 00' in the year 1742 and about 7 west in the 
 year 1782." Within three or four years, it has been mention- 
 ed in several periodical publications, that the variation had 
 ceased to decrease, and was then rapidly increasing. This 
 was stated to be the case, particularly in New York by per- 
 sons, who, from their official situations as public surveyors, 
 were supposed to be most competent to judge of the sub- 
 ject ; and observations were adduced to prove, that this change 
 had taken place between the years 1804 and 1807. Thus, 
 one of the boundary lines of Rensselaer Parish in Albany was 
 found in the year 1800, N. 46 48' W., by compass ; and in 
 the year 1806, N. 46 12' W., the true bearing being N. 51 46' 
 W. Whence it was inferred, that the variation had increased 
 36' during that period. In Herkimer, in New York, the varia- 
 tion was observed in the years 1800, 1804, and in 1807. In 
 the first interval of four years, it had decreased 4', and in the 
 last interval of three years, had .increased 15'. A turnpike 
 road, which was laid out by compass in 1805, had varied in 
 its bearing in 1807, 45', indicating that the variation had 
 increased by that quantity. (See tSillimarts Journal, April, 
 1829.) 
 
 105. From all these facts and observations, it is evident, 
 that the American magnetic pole has an irregular, oscillatory 
 motion from west to east, and from east to west, caused by 
 unequal accumulations of ice in the polar regions. Professor 
 Sewall has stated, in the Memoirs of the American Academy, 
 that the needle varied 47' west in about two or three 
 months, in the year 1782. Dr. Bowditch thinks, that 
 
102 A NEW THEORY OP 
 
 "the above differences of variation are not too great to be 
 accounted for by the diurnal variation alone." There can be 
 no doubt, that the annual, monthly, and diurnal variations are 
 greater in the United States, than in England, owing to the 
 greater variations of temperature. The diurnal variation of 
 the needle in England, according to the observations of Can- 
 ton, are 6 minutes 58 seconds at the winter solstice, and 13 
 minutes, 21 seconds at the summer solstice. In the United 
 States, the daily variation of temperature is frequently 60, 
 while in England, it is rarely half so much.* Moreover, the 
 annual range of temperature in the middle and northern por- 
 tions of the United States, is from 100 to 140, while in 
 England, it is seldqm more than 80. According to observa- 
 tions made by Mr. Reuben Haynes, at Germantown, latitude 
 40 3' near Philadelphia, the mean temperature was 49 6', 
 in 1821 52 4', in 182250. 5', in 1823 and 54 2', in 
 1825. During the years 1826 and 1827, at New York, it 
 was about 54; from all which it appears, that the mean 
 annual temperature of different years varies several degrees 
 doubtless, owing to partial accumulations of ice in the northern 
 seas, which are temporary in their duration. 
 
 106. According to tables of temperature taken from the 
 annals of chemistry and physics, the extremes of temperature 
 in central Europe, are from 5 of Farenheit in winter to 95 
 and 98 in summer. In the year 1795, the mercury fell to 
 1 below zero in France, but it was an extraordinary event, 
 and perhaps may not occur again in a century. It is not very 
 
 * M. Hansteen fancifully observes, that " the variations of the magnetic needle, 
 are a mute language revealing to us the changes perpetually going on in the 
 interior of the earth." If he had said the changes of temperature perpetually 
 taking place on the surface of the earth, we should have agreed with him. 
 
TERRESTRIAL MAGNETISM. 103 
 
 often that the mercury falls below zero in the United States, 
 south of latitude 43 N., except on elevated situations, so that 
 we have presented the extremes of temperature rather than 
 the general character of the climate. 
 
 107. Observations on the variation of the needle, as well 
 as those on the temperature of different climates, must be 
 continued for a considerable time, and the mean of the whole 
 accurately calculated before they can be relied on. Unfortu- 
 nately, the observations from which our magnetic charts are 
 constructedj are not all of this character. There is nothing 
 more wanted at the present time, than a series of well con- 
 ducted experiments and observations on the variation, dip, 
 and intensity of the needle in different parts of the world. 
 The result of M. Hansteen's observations in the north of Eu- 
 rope and Asia, have been a valuable acquisition, as far as they 
 go ; but we are greatly in want of more extensive and precise 
 information from other parts of the globe, especially in the 
 southern hemisphere. We trust that Dr. Breda will supply 
 this defect, during his voyage to the Antarctic circle, as far as 
 possible. 
 
 108. We shall now endeavor to explain why the American 
 centre of greatest cold has shifted several degrees from west 
 to east within the last hundred and fifty years. 
 
 109. We have shown that the Greenland Sea was closed with 
 ice from the fourteenth to the seventeenth century or longer 
 that it was probably obstructed in a similar way, nearly 2000 
 years ago, by which the northern ice was prevented from float- 
 ing southward therefore must have accumulated in, and co- 
 vered the Arctic Sea and lowered its temperature. During such 
 a state of the northern ice, the winds of the polar winter blew 
 
104 A NEW THEORY OF 
 
 over them, without receiving warmth as from a body of deep 
 water by which a change of climate was extended to the 
 lower latitudes. If the climate of Europe were really colder 
 during the greatness of Rome,* and from the fifteenth to the 
 seventeenth century, than from the eighth to the fifteenth 
 century, when the Greenland Sea was annually open, and 
 when the vine flourished in England^ the above causes must 
 account for it. 
 
 110. During a long continued accumulation of ice around 
 the northern coasts, the rivers would be perpetually frozen 
 up in their beds, or accumulated in icy ramparts at their 
 mouths. The valleys would be filled with snow arid ice- 
 bergs and the whole surface of the northern interior would 
 become a theatre of perpetual congelation, from Hudson's Bay 
 to Melville Island. During such a state of things, the centre 
 of greatest cold would be found near the longitude of Melville 
 Island, which is near the northern centre of the continent. 
 Accordingly, we find from observations made at the University 
 of Cambridge, and recorded in Professor Silliman's Journal, 
 volume XVI., that the magnetic pole was several degrees fur- 
 ther west one hundred and fifty years ago, than at present, as 
 the western variation of the needle was then 11 15' at Bos- 
 ton, and is now only about 6 west.t From Captain Parry's 
 
 * Greece, Turkey, Wallachia, Moldavia, and Hungary, where the vine arid 
 olive now flourish, are described by ancient writers, as having 1 a climate similar to 
 that of Russia and Sweden, in our times. In France, also, the rivers were frozen 
 over much more frequently, and for longer periods, in the time of Cajsar's cam- 
 paigns in Gaul, than at present. 
 
 t It is a remarkable fact, that during this period, the western variation was only 
 4 3(X at London, whereas it is now about 24, which clearly demonstrates, that 
 the needle did not then obey either the American or Asiatic pole in the west of 
 Europe, but some other intermediate point of magnetic attraction, which has 
 since disappeared. 
 
TERRESTRIAL MAGNETISM. 105 
 
 observations, the American pole is now about 102 west longi- 
 tude, which is several degrees east of Melville Island. In all 
 this we perceive nothing like a revolutionary movement of the 
 " cold meridians," or magnetic poles, round the geographical 
 poles. The truth is, that such a revolutionary movement is 
 utterly impossible, for this plain reason, that all other things 
 being equal, the greatest cold in the polar circles must always 
 accompany the largest body of fixed surface. It is equally 
 evident, that they cannot remain permanently stationary ; 
 but must shift in obedience to those laws which regulate the 
 temporary accumulations and dissolutions of ice in the northern 
 seas. In 1824, during his third voyage. Captain Parry found 
 the icy barrier in Baffin's Bay one hundred and fifty miles 
 broader, than when he passed it in 1819, proving that the 
 accumulations of ice are greater during some years than 
 others. 
 
 111. Posterity will wonder at the pertinacity of the British 
 government in sending their brave and intrepid navigators 
 repeatedly through Baffin's Bay, in quest of a north-west pas- 
 sage, after .such clear demonstrations of its being near the 
 coldest part of the northern hemisphere. Why did they 
 not explore the north of Greenland by land, and ascertain 
 how far it extends towards the pole? or why did they not 
 make an effort to pass round Greenland and the northern 
 continent ? It is highly probable that they might have failed 
 even then, as the great extent of continent at its northern 
 extremity, acts as a perpetual barrier to the arctic ice, which 
 would otherwise be floated southward during summer, and 
 leave the northern sea open. The failure of Captain Parry in 
 his attempt to approach the pole on the ice, from Spitzbergen, 
 
 14 
 
106 A NEW THEORY OF 
 
 in 1827, furnishes no argument against the possibility of na- 
 vigating the Arctic sea beyond the continent, if undertaken 
 at the proper time. On the contrary, he states that the gene- 
 ral movement of the ice southward, carried them back 
 faster than they were able to advance northward, which 
 proves that the ice does break up during summer. He more- 
 over states, that the temperature was milder, and that more 
 rain fell north of Spitzbergen, while they were on the ice, 
 than they had encountered during the seven summers which 
 they spent in the Arctic regions.* 
 
 112. We have seen that the strongest magnetic pole of the 
 northern hemisphere, is not far from latitude 72 north, longitude 
 102 west, on the American continent and that the weaker 
 north pole is on the Asiatic continent. Hansteen placed it 
 in latitude 85 12' north, and longitude 140 6' east from 
 Greenwich, in the year 1820. We before stated, that a strong 
 probability existed of there being two poles in the north of 
 Asia. The truth is, our information is very imperfect in 
 relation to the exact position of the magnetic poles and still 
 more so, in relation to the lines of no variation. Future 
 and more accurate observations are greatly wanted. 
 
 * We are strongly inclined to believe, with an intelligent writer in the Ameri- 
 can Quarterly Review, vol. vi., that " the north-west passage should be attempted 
 by passing round Icy Cape, and sailing eastward, with the west wind, through the 
 polar sea." We have no doubt, that the passage might be effected in that way, 
 if undertaken in July or August, after the ice in the Arctic Sea is broken up and 
 dissolved, as there is known to be a constant current from west to east, north of the 
 continent. Will this government neglect the opportunity of sending an expedition 
 suitably equipped, for the purpose of achieving this long desired object? Or will 
 it choose rather to suffer our naval vessels to rot in our dock yards, and our 
 officers to remain unemployed ? If so, we shall despair of republics doing any 
 thing towards the advancement of science. 
 
TERRESTRIAL MAGNETISM. 107 
 
 113. The strongest pole* of the southern hemisphere, accord- 
 ing to Professor Hansteen, is situated in south latitude 68 
 52', and 132 35' east, from the meridian of Greenwich, south- 
 west of Van Diemen's Land ; and the weakest pole of the 
 same hemisphere, is situated to the south-west of Terra del 
 Fuego, in latitude 78 16', and longitude 135 59' west from 
 Greenwich. That there is a body of land in that region is 
 proved by the fact which is stated by Captain Fanning, that 
 toward the pole, there are soundings in from fifty to one 
 hundred fathoms of water, between latitudes 66 and 69, and 
 in longitude 140 west. M. Hansteen supposes, that " these 
 four poles revolve around the geographical poles in unequal 
 periods from west to east that the American magnetic pole 
 will perform its circuit round the north pole in 860 years, and 
 the Asiatic pole in 1760 years that the strongest pole in the 
 southern hemisphere accomplishes its revolution round the 
 south pole in 4609 years ; and the weaker one in 1304 
 years." 
 
 114. We shall add but little to what we have already said 
 on this hypothesis. It appears to have no other foundation 
 whatever, than the shifting of the magnetic poles a few de- 
 grees from west to east, within the last two hundred years. 
 Had the movements of the poles been uniform in given pe- 
 riods of time, there would be some ground for supposing a pe- 
 riodic revolutionary progress round the poles of the earth's axis. 
 But we know, from the best authenticated observations, that 
 their movements are irregular, and even retrograde that the 
 
 * It is highly probable, if not demonstrable, as we shall see presently, that the 
 strongest magnetic pole in the southern hemisphere, is situated about midway 
 between the poles south of Terra del Fuego, and of Van Diemen's Land and 
 that the needle obeys it over more than two hundred degrees of longitude. 
 
108 A NEW THEORY OF 
 
 pole south of Van Diemen's Land has been nearly stationary 
 for the last one .hundred and fifty years while the North 
 American pole has been nearly stationary for the last forty- 
 five years, but with a slight retrograde motion within the last 
 thirty years. We also know, that they are perceptibly influ- 
 enced by the annual, monthly, and diurnal changes of tem- 
 perature from which we infer, that all the complicated phe- 
 nomena of magnetic polarity, are resolvable into the operation 
 of those laws which regulate the distribution of temperature 
 throughout the globe ; and not to " the revolutionary move- 
 ments of imaginary axes in the interior of the earth." 
 
 115. In addition to the facts which we have already ad- 
 vanced, to prove the connection of magnetic polarity with the 
 unequal distribution of temperature in the tropical and polar 
 latitudes, we find from the observations of Professor Hansteen, 
 that the maximum intensity of the magnetic force, prevails 
 during winter* when the difference between the temperature 
 of the tropical and polar latitudes is greatly increased and 
 that the minimum intensity of magnetic attraction occurs 
 during summer. This is readily understood when we reflect, 
 that the mean temperature is always the same at the mag- 
 netic equator, while it is from sixty to eighty-five degrees 
 lower at the American magnetic pole during the long winter 
 night, than during the long summer day. M. Hansteen also 
 found, that the dip was about fifteen minutes greater during 
 summer, than during winter, which must be owing to a dimi- 
 nution of horizontal intensity during summer. He also found, 
 that the dip was from four to five minutes greater in the fore- 
 
 * M. Kuppfer, of St. Petersburg-, has recently verified Hansteen's observations 
 -on tho difference between the dip and intensity during- summer and winter. 
 
TERRESTRIAL MAGNETISM. 109 
 
 noon thaivin the afternoon, which is also owing to the dimi- 
 nished horizontal intensity while the sun is on the magnetic 
 meridian. M. Hansteen and Mr. Christie have proved by 
 numerous observations, that the magnetic intensity has a daily 
 variation, the minimum occurring between ten and eleven 
 o'clock in the forenoon, and the maximum between four and 
 five in the afternoon.* Hansteen found the greatest daily 
 variation least in winter, and greatest in summer. 
 
 116. An effort was made in the year 1804, at the desire of 
 the French government, by Guy Lussac and M. Biot, to as- 
 certain whether the magnetic force experiences any perceptible 
 diminution at considerable elevations above the surface of the 
 earth. For this purpose they ascended together in a balloon 
 to the height of 13,124 feet, where they discovered no appre- 
 ciable difference. They state, however, that they found it 
 impossible to keep their balloon steady, which to a consider- 
 able extent, neutralizes the value of their experiments ; espe- 
 cially as other observers, equally accurate, have arrived at 
 different conclusions, under more favorable circumstances. M. 
 Kuppfer found a considerable diminution of magnetic intensity 
 on ascending mount Elbrouz in the Caucasus, in the course 
 of a journey undertaken by order of the emperor of Russia, 
 in 1829 ; and that " the decrease was much more consider- 
 able than is conformable with the commonly received hy- 
 pothesis of a focus of magnetic power situated at the centre 
 of the globe." M. De Saussure had previously inferred, from 
 some experiments which he made on the Col du Geant, near 
 Mont Blanc, at the height of 11,270 feet, that "the magnetic 
 force of the earth was reduced to four fifths of what it was in 
 the plains below." (See Lib. of Useful Knowledge, No, 
 
 * See M. Hansteen's observations in Appendix. 
 
110 A NEW THEORY OP- 
 
 107, part III. Art. Mag.) If the unequal distribution of 
 caloric in the lower and higher latitudes be the cause of mag- 
 netic polarity, there must be a diminution of intensity as we 
 ascend from the surface, because there is less difference of 
 temperature between the upper regions of the atmosphere 
 in the tropical and polar latitudes, than at the earth's surface 
 on a level with the sea. 
 
 117. Professor Hansteen found a striking variation of in- 
 tensity on ascending and descending the Round Tower in 
 Copenhagen, which is one hundred and twenty-six feet high, 
 with a walk of seven turnings which leads to the top. After 
 several experiments below, which showed, that seven hundred 
 and eighty-seven seconds of time were required to make three 
 hundred oscillations, he returned to the tower, and found 
 in the highest part of it, that three hundred oscillations 
 required - 842".37 
 
 One turning below required 836.57 
 
 Two turnings lower, 837.30 
 
 One and a half turnings lower, 834.43 
 
 Two turnings lower, 804.07 
 
 Down below within doors, 813.00 
 
 (See Edinburgh Philosophical Journal, vol. 4, p. 299.) 
 
 118. We have perceived, that the intensity, variation, and 
 dip of the magnetic needle are governed by periodic changes 
 of temperature. The irregular disturbances of the needle 
 are caused by thunder-storms, great falls of snow, violent 
 winds, volcanic eruptions, and the aurora borealis ; all of which 
 phenomena are immediately connected with the agency of 
 caloric. 
 
 119. The variation of the needle increases as we advance 
 
TERRESTRIAL MAGNETISM. Ill 
 
 from the magnetic equator to the poles, in proportion as the 
 distance diminishes viz., the difference between the angles 
 of variation in the lower and higher latitudes, is proportional 
 to the different lengths of the angles. Accordingly we find 
 that at St. Thomas, which is near the magnetic equator, the 
 variation is about 19 west, while at London, which is near 
 the same meridian, the variation is 24 west, and at Iceland it 
 is 40 west. At the latitude of Good Hope in Greenland, it 
 is 51 west, and at the latitude of the magnetic pole, it is 90 
 west, making a right angle, and pointing due west. If we go 
 north of the magnetic pole, it points to the south if to the 
 west of it, it points east varying between all the intermediate 
 points. In 1778, the variation was found by Captain Cook 
 to be 19 51' east, at Nootka Sound, and 35 37' east, at Beh- 
 ring's straits. At the mouth of the Mackenzie River, in latitude 
 69 29', longitude 135 41', Captain Franklin found the varia- 
 tion 51 42'. 
 
 120. It would seem that in the north of Europe, the 
 needle is influenced by some intermediate point of attrac- 
 tion between the American and Asiatic poles, as it varies 
 only 8 west at St. Petersburg which is 30 east from Green- 
 wich. At Stockholm, 18 east longitude, the variation is 15 
 30' west. At Christiana in Norway, in longitude 10 30' east, 
 it is 20 west. At North Cape, in Lapland, in longitude about 
 25 east, the variation is 6 west. In high latitudes, near the 
 magnetic pole, the daily variation is much greater than in 
 lower latitudes. At Port Bowen, Captain Parry and Lieu- 
 tenant Poster found it from three to five degrees, and even as 
 high as seven degrees. 
 
 121. The most mysterious circumstance connected with 
 
112 A NEW THEORY OF 
 
 magnetic variation is, that on many parts of the globe there it? 
 no variation of the compass. For example, there is no variation 
 at Cape Hatterass, latitude 35 15' north, longitude 75 west 
 from Greenwich ; and at several other points in the United 
 States. At Pekin and Canton in China, and in many other 
 parts of Asia, the needle points nearly due north ; also at 
 Archangel in the north of Europe. In the southern hemis- 
 phere, the needle points to the south pole of the earth's axis at 
 the eastern extremity of Borneo, and in the longitudinal centre 
 of New Holland. According to Hansteen's Chart, there is no 
 variation in the Pacific Ocean in latitude 20 south, and longi- 
 tude 120 west. But as we before stated, the observations on 
 which our charts are constructed are too few and imperfect to 
 enable us to present a precise account of magnetic variation in 
 thfe southern hemisphere. 
 
 122. The reason why the needle points to the geographical 
 poles, and not to the magnetic poles at the above places, has 
 never yet been explained ; nor are we prepared to assign any 
 other cause, than that between the points where there, is no 
 variation and the true poles, there must be minor centres of 
 attraction^ which influence the needle more strongly than do 
 the magnetic poles, which are farther off. This influence is 
 obvious in the north of Europe, where the western variation is 
 much less than in England and France on the same meri- 
 dians ; which must be owing to the influence of Greenland and 
 Spitzbergen, which are situated between the meridians of St. 
 Petersburg and the American magnetic pole.. Perhaps the 
 needle may be also influenced by the centres of cold, in the 
 north of Europe and Asia. It is evident that the needle is af- 
 fected by intermediate centres of attraction between the tropics 
 
TERRESTRIAL MAGNETISM. 113 
 
 and the polar circles from the fact, that there is a diurnal varia- 
 tion during winter, while the polar circles are entirely excluded 
 from the sun's influence, which proves, that the daily variation 
 must be owing to the successive heating and cooling of the 
 magnetic meridians in lower latitudes^ caused by the daity revo- 
 lutions of the earth on its axis. The greater daily variation 
 during summer than winter, is probably owing to the sun's 
 sweeping daily round the pole in such a manner as to cause a 
 successive exposure of different meridians of the polar circle to 
 his influence while in winter, his daily heating influence is 
 limited to lower latitudes. 
 
 123. A few degrees west of the meridian of London 
 in the southern hemisphere, there is no variation, which 
 is evidently owing to a large body of land in the direction 
 of the true south pole. Captain Morrell, who has made impor- 
 tant discoveries in the southern hemisphere, informs me that 
 he coasted a continent or large body of land 47 beginning 
 west longitude 47 21', latitude 67 52' S., which he thinks 
 extends westward as far as 120 Q or 130 west longitude. 
 
 124. Judging from the direction of the needle, we are inclined 
 to believe that this continent extends south-east also, per- 
 haps as far as the eastern magnetic pole.* How far it extends 
 towards the south pole, it is impossible to say ; but reasoning 
 from analogy, and from the excessive coldness of New South 
 Greenland as described by Captain Morrell, it is not improba- 
 ble that it extends to near the south pole in the direction of the 
 true meridian from England. Captain Morrell states, that 
 
 * We have just seen in the New York Commercial Advertiser, an extract from an 
 English newspaper, stating, that a certain British whaler had recently discovered 
 land in the South Seas, extending from longitude east 47 3(X to longitude 69 29' 
 W., in high southern latitudes. 
 
 15 
 
114 A NEW THEORY OF 
 
 beyond latitude 60 there is no soil or vegetation on New 
 South Greenland; but a succession of vast mountains, or 
 columns of impenetrable rocks, ice, and snow : from which we 
 infer that it is even colder than Melville Island, as Captain 
 Parry 'found there a few species of stinted vegetation. 
 
 125. Captain Morrell thinks, that New South Greenland 
 is quite as cold in latitude 60, as North America in latitude 
 70 ; and that the mean temperature of the Southern ocean, 
 in latitude 50, is about equal to that of latitude 40 on 
 the North American continent : but as he did not winter on 
 New South Greenland, nor remain any length of time at one 
 place, he could give no thermometric tables. 
 
 126. We had inferred the existence of a third centre of 
 magnetic attraction of great power situated not far from the 
 true south pole, from the direction of the needle, which points 
 due south, a few degrees west of the Cape of Good Hope and 
 from the great number of enormous icebergs frequently met 
 with, south-west of the Cape, which are known to be formed 
 among mountain valleys, and not in the sea ; from which we 
 concluded that there must be a large body of land towards the 
 south pole where these icebergs were formed, and a centre of 
 cold proportional to its extent and elevation. Since completing 
 this essay, we met with Captain Morrell, who confirmed our 
 hypothesis previously founded on analogy, by stating that he 
 had coasted a new continent 47 Q of longitude. 
 
 127. We have seen that the needle is not directed by the 
 pole of the earth in the northern hemisphere, but by the centres 
 of greatest cold, and that these centres of maximum cold are 
 caused by large bodies of land in high latitudes, where icebergs 
 are formed, from which they descend into the sea, and are 
 
TERRESTRIAL MAGNETISM. 115 
 
 carried by the polar currents to lower latitudes. We hesitate 
 not to assert, that there never was, and never will be a centre 
 of magnetic attraction, situated over a large expanse of water, 
 far from land. 
 
 128. Should there be a continuous body of land from the 
 eastern south pole, to the Terra del Fuego pole, it is more 
 than 4000 miles long, and if it extends far towards the true 
 pole, it must be greatly colder than arctic America. That 
 there is a large body of land in the direction of the strongest 
 south pole ; and also in the regions of the weaker magnetic 
 poles, we have no doubt. This land may be divided by Bays 
 or Straits, of greater or less extent ; and it may extend farther 
 south in the neighborhood of the magnetic poles, than in other 
 portions of the antarctic circle. From the extreme coldness of 
 New South Greenland, we venture to predict, that ships will 
 not approach very near the south pole. 
 
 129. It is highly probable, that M. Hansteen has placed the 
 Asiatic pole several degrees too far north, as we have numer- 
 ous accounts from the Greenland whalers of a heavy swell from 
 the north east of Spitzbergen, proving, that the sea is open in 
 that direction : and because persons who have passed the 
 winter at Kola in Lapland relate, that during the severest 
 weather, whenever a northerly wind blows, the cold diminishes 
 instantly, and that if it continues, it always brings on a thaw 
 as long as it lasts. When Captain Parry wintered at Melville 
 Island, he discovered the same effect, but in a less degree. 
 
 130. Barrington says, " it is the invariable tradition of the 
 Samoides and Tartars, who live beyond the Waygat, that the 
 sea is open to the north of Nova Zembla all the year ; and that 
 the most knowing people of Russia are of the same opinion." 
 
116 A NEW THEORY OF 
 
 From all these circumstances taken together, and from the fact 
 that the exact position of the Asiatic pole has never been ascer- 
 tained by finding where the dipping needle would become verti- 
 cal, we are disposed to believe that it is not so far north as eighty- 
 five degrees It is much to be regreted, that we have not at 
 present a sufficient number of accurate observations, on the 
 temperature of northern Asia and Europe, to determine posi- 
 tively whether there be two centres of cold on the eastern 
 continent. The accumulation of ice around the continent, 
 and at the mouths of its great rivers, must greatly influence 
 their position, at different periods.* The absence of a swell 
 from the north-west of Spitzbergen may be owing to the in- 
 termediate position of Greenland ; or to the prevalence of ice 
 in the Arctic Sea, north of the American continent, which is 
 doubtless often the case. 
 
 131. The pointing of the needle to the true north pole at 
 Cape Hatterass, may be owing in part to the coldness of the 
 Appalachian mountains, which trend somewhat toward the 
 north pole, and which may deflect the needle from the direction 
 of the magnetic pole, to that of the true north pple. The lofty 
 mountains of the eastern continent from the Himalayas of 
 thes outh, to the Stavonoys of the north-east, and the Urals 
 stretching north between Europe and Asia also, the cold 
 elevated table lands of central Asia, must produce what Dr. 
 Brewster terms "cold meridians," or centres of cold, which 
 deflect the needle from the distant magnetic pole, and direct it 
 towards other points. Accordingly, we find the variation lines 
 in Asia, very crooked and complicated. 
 
 132. So feeble is the directive power of the needle near the 
 
 * See tables of magnetic variation in the Appendix. 
 
TERRESTRIAL MAGNETISM. 117 
 
 magnetic pole, that in Regent's Inlet, Captain Parry found it 
 overcome by the attraction of the ship's iron.* Captain Scoresby 
 has estimated the force of local attraction caused by the ship's 
 iron, at about one-eleventh of the directive power in England 
 in Greenland where the compass traverses well, he found the 
 number of oscillations of a horizontal needle, fewer in a given 
 time than in England. He also thought that in a low tem- 
 perature, the vibrations performed by the needle before it stop- 
 ped were fewer. Captain Ross concluded from his experi- 
 ments on local attraction, that the deviation appeared to be 
 materially affected by heat and cold, as well as by atmos- 
 pheric humidity and density ; and that the direction of the 
 wind seemed to have an irregular effect on the deviation. 
 
 133. Captain Scoresby says, that the greatest deflection of 
 the needle from the magnetic meridian, occurs when the ship's 
 course is east and west ; because the focus of attraction then 
 operates at right angles to the position of the compass needle ; 
 but the anomaly generally disappears when the course is about 
 north or south, because the focus of attraction is then in a line 
 with, or parallel to the compass needle, and consequently has 
 no power to deflect it from its direct position. (See Arctic 
 Regions, Vol. //., p. 548.) The extraordinary variation of 
 Captain Parry's compasses, in latitude 68, off Igloolik, must 
 have been caused by local attraction of the ship's iron, over- 
 coming the directive power, while the ship's head was east. 
 Captain Scoresby occasionally carried a compass in the crow's 
 nest, fixed at the mast-head, " where it was found to be free 
 from the anomalies \vhich are so sensible in a compass'on deck." 
 ( See Arctic Regions, p. 549.) Captain Scoresby has given 
 
 * See Sections 92 and 95, Part II. ' 
 

 118 A NEW THEORY OF 
 
 numerous examples t>f shipwreck, caused by the deviation of 
 the needle in ships loaded with iron, steel, &c. 
 
 134. It has been an established article of belief among all 
 writers on magnetism, that the needle is influenced simulta- 
 neously by the poles of both hemispheres. For example, that 
 the south end of a compass needle placed on any point of North 
 America, obeys the pole south west of Terra del Fuego, while 
 the north end is directed by the North American pole. We 
 have seen that the South American pole is more than 30 west 
 of the North American pole, from which it is evident, that the 
 needle cannot obey both poles at the same time at New York, 
 London, Paris, &c., because if it did, it could never point to 
 either pole, but would assume an oblique direction. There 
 is another fact which is decisive on this point. At London (in 
 the northern hemisphere) the variation is 24 west, while on 
 the same meridian in the southern hemisphere, the needle 
 varies only two or three degrees from the true meridian, 
 which is proof positive, that the needle does not obey the north 
 and south poles simultaneously. It is probable that at the 
 magnetic equator, it is influenced by both, though unequally, 
 according to their relative power.* 
 
 135. I have no doubt, that for 100 east, and nearly 120 
 west of the meridian of Greenwich in the southern hemisphere, 
 the needle obeys a third centre of magnetic attraction, as before 
 suggested, which is situated not far from the meridian of 
 London, and which has never before been suspected to exist. 
 We can readily understand why the variation is so small on 
 
 * The directive power or intensity of the needle must be in proportion to the 
 amount of/ree, or radiant caloric, which passes from the tropical to the polar 
 regions ; which, probably, acts upon it in a mode somewhat similar to that of an 
 atmospheric current, on the vanes of our church steeples. 
 
TERRESTRIAL MAGNETISM. 119 
 
 the meridian of London in the southern hemisphere, if there 
 be a centre of magnetic attraction in the direction of that 
 meridian. Until the above facts are understood and recog- 
 nized, our magnetic charts will continue, as they have here- 
 tofore been, only stumbling blocks, to those who engage in 
 magnetic inquiries. Without a great deal of patient and inde- 
 pendent research, we should have been discouraged on our first 
 examination of Dr. Halley's chart, corrected and improved by 
 Mountaine and Dodson. It was a perfect enigma, which never 
 could have been solved without a recurrence to first principles. 
 By the way, it is not those who perform the greatest number 
 of experiments, or collect the greatest number of facts and 
 observations who do most to advance knowledge ; but those 
 who reduce a chaos of undigested phenomena to order point 
 out their relations and deduce from them general principles 
 for the direction of other experimenters. Indeed, there is no- 
 thing more fallacious than experiments, when not guided by 
 general principles. 
 
 136. We have seen that there is no necessity for resorting 
 to a central magnet extending through the earth's axis, nor to 
 'accumulations of iron at the poles, to account for magnetic 
 polarity. Every thing in nature is more or less magnetic. 
 When any two substances are brought near to each other, if 
 differently electrified, they attract each other. When two pith 
 balls are differently electrified, they become magnetic. When 
 glass or amber is rubbed, they become magnetic, attracting 
 light bodies to them.* From the few experiments we have 
 made, we believe that every solid .substance in nature may be 
 
 * The same is true of the metals, if insulated when rubbed. 
 
120 A NEW THEORY OF 
 
 rendered magnetic by friction, which developes caloric. In 
 fine, we believe that the earth is magnetized by solar heat, and 
 that all the diversified phenomena of magnetic attraction are 
 resolvable into the subtle, silent agency of caloric in some of its 
 forms. 
 
 137. From numerous experiments of Caulomb, Hansteen, 
 Scoresby, Harris, and many other philosophers of Europe, we 
 learn that almost every species of solid substance, mineral and 
 vegetable, in a greater or less degree is susceptible of magnet- 
 ism. Caulomb proved this by placing needles formed of wood, 
 bone, glass, and many other substances, between steel mag- 
 nets, of opposite polarities, " when they arranged themselves in 
 the direction of the magnetic meridian, and if disturbed from 
 their position, they always returned to it with oscillations." (See 
 Library of Useful Knowledge, on Magnetism.) Captain 
 Scoresby ascertained, that a few blows with a hammer, ren- 
 dered steel magnetic, when held in the direction of the dipping 
 needle, and that magnets could be made at any time in that 
 way. In addition to which, we have ascertained by repeated 
 experiments, that iron and steel may be rendered strongly mag- 
 netic by friction between two plates of unmagnetized iron or 
 steel, without any reference to the position in which they may be 
 placed and that the various species of metal, wood, sealing 
 wax, glass, and even paper, will assume a polar direction, if 
 placed on water, after being warmed by friction. An important 
 fact connected with this part of the subject is, that in the polar 
 regions, compass needles lose their magnetism much sooner 
 than in the lower and warmer latitudes, as was observed by 
 Captain Parry and Lieutenant Foster. 
 
 138. It is highly probable, that nearly all articles manufac- 
 
TERRESTRIAL MAGNETISM. 121 
 
 tured from steel arid iron are rendered more or less magnetic 
 by the friction which they undergo while forming and polish- 
 ing. Mr. Varley examined many dozen balances of time 
 pieces, out of which he could not find one that had not polari- 
 ty." (See .Edinburgh Philosophical Journal, Vol. IX. f p. 
 50.) I placed a dozen fine sewing needles on water in succes- 
 sion, all of which polarized, but some more speedily than 
 others. When rubbed between two metals, until warm to the 
 touch, they traversed briskly, and settled very soon in the di- 
 rection of the magnetic meridian. Soon after communicating 
 our views of the connection between caloric and magnetism 
 to a gentleman of this city, he submitted the blade of his pen- 
 knife to friction on the face of a smoothing iron, with a com- 
 mon poker when it became strongly magnetic. We have 
 performed the experiment in various ways, and always with 
 the same result. Great irregularities in the time of chrono- 
 meters have often resulted from the balance wheel becoming 
 magnetic. Captain Scoresby has suggested a mode of recti- 
 fying the 'errors of chronometers by suspending them in such 
 a way that they will always keep in the same position at sea, 
 with respect to the magnetic meridian. (See Edinburgh 
 Philosophical Journal, Vol. IX., p. 54.) 
 
 139. The production of magnetism in steel and iron by 
 electricity, was known to our countryman, Dr. Franklin, and 
 to the celebrated Beccaria, more than fifty years ago ; but was 
 first demonstrated by a series of well conducted experiments 
 by Dr. Oerstedt of Copenhagen, in 1819- Professor Moll of 
 Utrecht, M. De la Rive of Geneva, M. Arago of Paris, Dr. 
 Wollaston, Sir Humphrey Davy, Mr. Farraday, Mr. Hers- 
 chell, Mr. Christie, and many other philosophers of Europe, 
 
 16 
 
122 A NEW THEORY OF 
 
 
 have repeated and extended the experiments of Oerstedt, until 
 
 electro-magnetism has assumed the character of a separate 
 department of physical science. It Cannot be said, however, 
 that it has yet been reduced to a system of principles, or that 
 its relations to terrestrial magnetism have been satisfactorily 
 pointed out. 
 
 140. We shall present only a brief outline of the most im- 
 portant results -obtained by different experimenters. We would 
 observe at the same time, that the limited scale on which most 
 of these experiments are performed, render them less satisfac- 
 tory than a general survey of the operations of nature 
 throughout the globe, where the leading facts are exhibited on 
 a scale of comprehensive grandeur and certainty, which can- 
 not fail to arrest the attention of every enlightened mind. 
 For example, we are told by seamen, that on approaching ice- 
 bergs, the compass needle is frequently disturbed, as it is by 
 all sudden and great changes of atmospheric temperature. 
 We consider observations of this nature more decisive than a 
 hundred experiments made by ranging a few small pieces of 
 ice around the needle, and noting their effect upon it ; because 
 all such experiments must be partial, and modified by the ge- 
 neral magnetic influence of the earth. What the precise 
 mode may be by which caloric renders metals magnetic, we 
 are not prepared to say* nor is it of any more importance, 
 than that we should know precisely how the vital principle is 
 united with ponderable matter. We know the general fact, 
 that if iron or steel be made red hot, and suddenly cooled in 
 
 * Mr. Abraham of Litchfield, supposed, from a series of experiments, which 
 he performed, that magnetizing a steel needle, rendered it a better conductor of 
 electricity than in its ordinary state. (See PT, Greeris Work on Electro- Magnet- 
 ism, p. 104.) 
 
TERRESTRIAL MAGNETISM. 123 
 
 water, they become magnetic. We also know, that lightning 
 renders article^ of every description manufactured from iron 
 and steel magnetic and that it has often depolarized compass 
 needles, both on land and at sea. 
 
 141. But the most astonishing experiments ever exhibited 
 to the world, proving the agency of galvanic heat in the pro- 
 duction of magnetism^, are those performed by Professor 
 Henry, and Dr. Ten Eyck of Albany, in 1831, They con- 
 structed a horse shoe magnet of Swedish iron, weighing sixty- 
 nine and a half pounds, with an armature weighing twenty- 
 three pounds. Around this magnet they wound twenty-six 
 strands of copper bell wire, each thirty-one feet long, and 
 covered with cotton thread. About eighteen inches of the 
 ends of the wire were left projecting, so that the aggregate 
 length of the coils was seven hundred and twenty-eight feet. 
 On connecting the' wires with a battery of 4lths square 
 feet, the magnet supported 2063 pounds. In one experiment 
 with a smaller battery, the armature continued to support 
 more than one hundred and fifty pounds, three days after the 
 battery had been excited. 
 
 142. Professor Henry observes, that " several small wires 
 conduct more common electricity from the machine than one 
 large wire of equal sectional area ; and that the same is pro- 
 bably the case, though in a less degree, in galvanism." 
 Hence the advantage of multiplying the strands of wire in 
 order to increase the power of the magnet. With a single 
 pair of concentric copper cylinders, with zinc between them, 
 the whole amount of zinc surface exposed to the acid being 
 two-fifths of a square foot, and requiring only half a pint of 
 diluted acid for its submersion, caused a horse shoe magnet 
 
124 A NEW THEORY OP 
 
 weighing twenty-one pounds, and wrapped round with nine 
 strands of copper bell wire, each sixty feet lo^ng, to lift six 
 hundred and fifty pounds. 
 
 143. We consider the attraction of two smooth plates of 
 lead for each other, after being rubbed, of the same description. 
 They adhere with equal force under an exhausted receiver, 
 as under the pressure of the atmosphere : therefore must be 
 held together by some imponderable intermedium and as we 
 know that caloric is developed by friction, and actually does 
 exist between the plates, we infer that it causes their attractive 
 force. 
 
 144. It is stated by Dr. Green, that the heat of the hand 
 will produce a sensible declination in a delicately suspended 
 needle and that Lieutenant Johnson, of the British navy, 
 observed a considerable variation of the compass needle, by 
 simply wiping the dust from the glass cover with a silk hand- 
 kerchief or other soft substance also, that the rays of the 
 sun in their passage through the glass alter its electrical state, 
 and cause it to affect the needle. (See a late work on Electro- 
 Magnetism, by Jacob Green, M. D., Professor of Chemis- 
 try, in Jefferson College.} From the above facts and obser- 
 vations, it is obvious that compass needles should be placed in 
 boxes of wood, or some other imperfect conductor of heat, as 
 recommended by Mr. Fox. The needle should not be too 
 light, and the cylindrical form least exposes it to being 
 disturbed by currents of air. When great accuracy is required, 
 these precautions are indispensable, and the glass covers should 
 be double. Dr. Yelin inferred from his thermo-magnetic ex- 
 periments, "that all metallic bodies acquire magnetic pro- 
 perties, when their various parts are unequally heated, and 
 
TERRESTRIAL MAGNETISM. 125 
 
 that the action is stronger as the difference of temperature is 
 greater." (Bib. Univers. XXIV.) . 
 
 145. Whenever an oblong metal is brought near to a prime 
 conductor, it becomes electrified positively at one end, arid ne- 
 gatively at the other end. If the positive end of a wire thus 
 electrified, "be brought near to the negative end of a similar 
 wire, they attract each other but if either the positive or ne- 
 gative ends be brought together, they repel each other. The 
 same law applies to magnets poles of the same character repel, 
 while opposite poles attract each other. When, however the 
 north pole of a large magnet is brought near to the north pole of 
 a small magnet, they attract each other an exception to the 
 general law, which I ascertained by repeated triate, and which 
 T have not seen noticed by writers on magnetism. 
 
 146. It has been demonstrated mathematically, by ^Spinus 
 and Caulomb, that the attraction and repulsion of electricity 
 and magnetism, like that of gravitation, operate inversely, 
 as the squares of the distance and Mr. Harris has proved, 
 " that every substance susceptible of magnetism by induction, 
 interposed as a screen, tends to arrest the action exerted by a 
 magnet on a third substance. 55 He determined that this 
 interceptive influence is as the mass of intervening substance, 
 and inversely, as its susceptibility of receiving induced mag- 
 netism. He inferred from various experiments with different 
 substances, that this interceptive property is common to all 
 matter, though possessed in various degrees, by different kinds 
 of substances, and that in order to render it sensible, it is only 
 requisite to employ them in masses proportionate to their re- 
 spective magnetic susceptibilities." (Lib. of Useful Know- 
 ledge Article, Magnetism.) It is well known, that a thin 
 
126 A NEW THEORY OP 
 
 coating of wax, which is a bad conductor of electricity, greatly 
 diminishes the power of a magnet ; and Dr. Pascalis informs 
 me, that the cocoons of the silk worm, totally intercept the 
 magnetic influence. 
 
 147. When a metal or other substance, becomes saturated 
 with electro-magnetism, further induction is prevented by the 
 repulsion of the electric particles, which seek to expand them- 
 selves and thus impart electric currents to other substances 
 less electric, rendering them also magnetic. M. Arago, 
 showed in 1824, " that if a plate of copper, or of any other 
 substance, be placed immediately under a magnetic needle, 
 it exerts sufficient influence upon its movements, to diminish 
 sensibly the extent of its oscillations. The needle is brought 
 to rest in a shorter time than happens when no such sub- 
 stances are placed under it." He further ascertained, " that 
 when a circular plate of copper is made to revolve with a cer- 
 tain velocity, under a magnetic needle, supported on its centre, 
 and contained in a vessel closed on all sides, the needle is 
 found to deviate from its natural position in the magnetic me- 
 ridian ; and the deviation is greater in proportion as the rota- 
 tion of the plate is more rapid. If the rapidity of revolution 
 be sufficiently great, the needle will be brought to revolve also, 
 and always in the same direction in which the plate is made 
 to revolve." (See Library of Useful Knowledge, on Mag- 
 netism.) 
 
 148. M. Ampere, who has devoted much attention to the 
 science of magnetism, refers it entirely to electricity ; but he 
 explains all the phenomena of magnetism by " the action of 
 electrical currents, moving at right angles to the magnetic 
 meridians." 
 
TERRESTRIAL MAGNETISM. 127 
 
 149. Experiments, have been recently made in Italy, by 
 two distinguished philosophers, M. M. Nobili, and Antinori, 
 which exhibit more strikingly, the dependence of magnetism 
 on electricity, than any preceding experiments in electro-mag- 
 netism, and by which the electric spark was drawn from the 
 natural or permanent magnet. They have been repeated in 
 England with some modifications, by Faraday, Saxton, Ritchie 
 and Forbes, and in the United States, by Professors Emmet 
 and Silliman. M. Hachette, announced to the French Aca- 
 demy of Sciences, on the third of September, 1832, that Pixii 
 had constructed an electro-magnetic apparatus which produced 
 sparks at the distance of several mille-metres. It is well 
 known, that natural magnets retain their power for indefinite 
 periods of time, without much diminution from which we 
 are authorized to conclude, that they are constantly receiving a 
 supply of electricity from the earth and the atmosphere, by 
 induction. . 
 
 150. We have just learned that Professor Botto of Turin, 
 has repeated and extended these experiments and that 
 he "obtained fi^m a horse-shoe magnet, surrounded in the 
 middle with an electro-magnetic spiral, not only shocks, but a 
 current of electricity sufficient to decompose water, acetate of 
 lead, and other saline solutions." (See American Journal of 
 Science, April, 1833.) We must refer the reader for the par- 
 ticulars of these experiments, and for further information on 
 electro-magnetism in general, to the various scientific journals 
 of the day. 
 
 151. Mr. Boyle ascertained long ago, that if amber be ex- 
 posed to the sun's rays, it attracts light bodies ; and Colonel 
 Gibbs, an intelligent mineralogist of this state, has communi- 
 
128. A NEW THEORY OF 
 
 cated through -the American Journal of Science, the impor- 
 tant discovery, that when magnetic iron ore is first obtained 
 from the earth at considerable depths, it is much less magnetic 
 than after being exposed some time to the sun and air : from 
 which he infers, " that the sun is the source of magnetism." 
 The opinion of Colonel Gibbs is strongly corroborated by the 
 experiments of M. Barlocci and M. Zantesdeschi. Professor 
 Barlocci found that an armed natural loadstone, which would 
 carry one and a half Roman pounds, had its power nearly 
 doubled by twenty-four hours exposure to the strong light of 
 the sun. M, Zantesdeschi found that an artificial horse-shoe 
 loadstone, which carried thirteen and a half ounces, carried 
 three and a half more by three days exposure, and at last 
 supported thirty-one ounces by continuing it in the sun's 
 light. (See Backers American edition of Dr., now Sir 
 David Brewster^s Treatise on Optics.) The truth is, that 
 many distinguished philosophers have been verging towards 
 this opinion for sometime past and had they pursued the 
 subject more at large, uninfluenced by pre-existing theories, 
 they would probably have embraced it fully. , 
 
 152. Professor Moll asks the question, " is there not some 
 analogy between the sun's rays, and that force which so 
 strongly effects the magnetic needle ?" Dr. Brewster notices 
 the coincidence of the isothermal lines with the lines of equal 
 dip, and of the points of maximum cold with the centres of 
 magnetic attraction ; but maintains that they have a revolu- 
 tionary movement round the poles of the earth by which he 
 has involved the whole subject in hypothetical speculation. 
 (See Edinburgh Encyclopedia, Article, Polar Regions.) 
 
TERRESTRIAL MAGNETISM. 129 
 
 153. Professor Hansteen also supposed, that terrestrial 
 magnetism was in some way connected with solar and lunar 
 influence ; but lost himself in a maze of speculation in regard 
 to the manner in which the sun was magnetized whether by 
 a central sun and whether the magnetic power was exerted in 
 a general direction throughout the univers% ; having the milky 
 way for its equator, &c. It has been our object to trace its 
 operations as exhibited on our own planet, and to show that 
 it is owing to the agency of causes perpetually before our 
 eyes. 
 
 154. Embracing, as M. Hansteen has done, the Halleyan 
 hypothesis of two magnetic axes in the interior of the earth, 
 and of their revolutions round the geographical poles, without 
 offering any satisfactory proofs of their existence, it may be 
 said that his theoretical views have shed but little light on 
 this difficult problem. 
 
 155. M. Hansteen says, " as to the origin of those mag- 
 netic axes, we may suppose them to have been created 
 along with the earth itself, or at a later epoch." How 
 unsatisfactory are the results of hypotheses ! Dr. Brewster 
 thinks, that beyond the mere elements, the whole science of 
 magnetism is still involved in obscurity. (Edinburgh Phil. 
 Journal.} 
 
 156. It is impossible to conceive how the sun could mag- 
 netize the interior of the earth, while its influence reaches 
 but a short distance below the surface ; so that this hypothe- 
 sis is obviously inconsistent. The facts, however, which M. 
 Hansteen has collected with so much labor and perseverance, 
 entitle him to the gratitude of all the lovers of science. 
 
 157. The absurdity of supposing a revolutionary move- 
 
 17 
 
130 A NEW THEORY OF 
 
 ment of the magnetic poles, must appear obvious, when we 
 learn, that according to M. Hansteen's theory, the American 
 pole must have been about Behring's Straits two centuries 
 ago ; and that four centuries ago, it must have been in the 
 north Pacific, or east of Asia. 
 
 158. If we adinjt the hypothesis of Halley and Hansteen, 
 that there are two magnetic poles in the interior of the earth 
 in each hemisphere, which revolve in unequal periods of time, 
 will it explain the phenomena of irregular and retrograde shift- 
 ing of the centres of magnetic attraction? Or the annual, 
 monthly, and diurnal variations of the needle 1 Or does it afford 
 any explanation of the mode by which these interior poles 
 affect the needle ? It is acknowledged, that distant objects 
 cannot act upon each other, without some intervening medium. 
 We have shown that such a medium does exist that caloric in 
 different forms, is abundantly distributed throughout nature 
 that it passes through the most ponderable bodies with great 
 facility, from where it is plus to where it is minus and finally, 
 that it is probably the cause of all the motions and changing 
 phenomena of matter. 
 
 159. Philosophers have strangely confounded the gravity 
 of matter with its inertia. There is no such thing as perfect 
 quiescence or inertia of matter. If we could conceive such a 
 thing as the entire annihilation of caloric, we might also con- 
 ceive of a total inertia of matter. The mind becomes bewil- 
 dered in contemplating the reign of eternal darkness and re- 
 pose, which would follow the universal extinction of caloric ; 
 unless it pleased the Almighty to create it anew. 
 
 160. I trust, that the numerous facts and analogies by which 
 I have arrived at the foregoing generalizations, will exempt me 
 
TERRESTRIAL MAGNETISM. 131 
 
 from the imputation of rashness, or of a wish to indulge in 
 hypothetical speculations. I have endeavored as far as possible 
 to confine myself to the inductive method, while the compli- 
 cated character of the subject, and the recondite nature of the 
 phenomena involved in its discussion, have presented many 
 obstacles to its perfect elucidation. 
 
 161. If I have been so fortunate as to shed any new light 
 on this important problem, I shall esteem it as the gift of Hea- 
 ven, for it came to me unsought and unexpected, while pursu- 
 ing another inquiry, without the slightest conception of the 
 great truths to which it gradually led the way. I had no 
 higher object than to ascertain the cause of unequal climates 
 in different parts of the globe, and especially the cause of une- 
 qual winters in our own climate; with an ulterior view of 
 obtaining some knowledge of the cause of epidemics. 
 
 162. The results have afforded me the more satisfaction, 
 as they were obtained before I examined a single theory in 
 relation to magnetism. Indeed, it is highly probable, that if I 
 had commenced the study of magnetism, by a perusal of the 
 various systems, I should have been bewildered in the laby- 
 rinth of contradictory facts and opinions which they contain. 
 
 163. The truth is, that we must revert to first principles^ 
 and study nature, or we shall never succeed in our efforts ta 
 extend the boundaries of truth. Are we forbidden to look 
 boyond the horizon of our predecessors ? What then is to be 
 the progress of science in future times ? Are we to surrender 
 the glorious privilege of free and independent inquiry for the 
 soul-paralyzing slavery of authority ? If so, farewell all those 
 pleasing hopes of human improvement which have been so, 
 
1 32 A NEW THEORY OF 
 
 idently cherished by the loftiest and purest spirits of our 
 race. 
 
 164. Should ignorance and malevolence assail me with 
 abuse, and misrepresent the character and tendency of my 
 labors, I shall regard them only, so far as they may be cal- 
 culated to diminish their usefulness for I hold every other 
 considerafon subordinate to the great business of benefiting 
 mankind and that there is no power on earth which can 
 deprive me the consolation which flows from a sincere desire to 
 promote the cause of truth. 
 
 165. We have conveyed our views in the most plain and 
 simple language, that every man of sense throughout the 
 great republic of science, may judge for himself how far they 
 are conformable to truth and reason. If they are not in ac- 
 cordance with facts, and the established principles of science, 
 they will of course sink into oblivion ; but, if they are fair de- 
 ductions from well-known phenomena, the cavils of pretended 
 philosophers will be in vain, for truth and nature must triumph 
 over all opposition. We have endeavored to interpret the great 
 volume of nature, as its pages are unfolded to the view of every 
 inquiring mind. 
 
 166. It may be said that we have not sufficiently verified 
 our doctrines by experiments ; to which we answer, that nature 
 has performed, and is continually exhibiting the most satisfac- 
 tory experiments on a scale of grandeur and fidelity, which, by 
 our manipulations, we can only imitate in a feeble manner. 
 We have drawn our proofs and illustrations from the most 
 familiar operations around us from the silent combustion of a 
 candle, to the magnificent displays of aerial lightning. 
 
 167. . It is acknowledged by all parties, that no previous 
 
TERRESTRIAL MAGNETISM. 155 
 
 theory has been sufficient to explain the phenomena of mag- 
 netic polarity, to say nothing of the hypothetical character of 
 the data on which they are founded : while it must be con- 
 ceded by every candid individual, that we have assumed no 
 hypothesis as the basis of our theory. 
 
 168. Professor Farrar of Cambridge, in a recent work on 
 Electricity and Magnetism, makes the following observations. 
 " The account which we have given of the present state of our 
 knowledge, respecting the magnetism of the globe, will serve 
 to show our imperfect acquaintance with this subject. And 
 ignorant as we are, of a great many necessary data, especially 
 of such as relate to the magnetic declination, we cannot expect 
 to discover the real cause of these phenomena" 
 
 169. If we have not unfolded all the relations of caloric 
 and electricity, we have at least proved that without caloric, 
 there is no electricity ; so that if the agency of electricity 
 be admitted, we must also admit the agency of caloric. 
 We pretend not to have left nothing yet to be discovered 
 in this immense science. Far from it. Sir Isaac Newton, 
 himself, left much to be done by his successors, before the 
 laws of gravitation were perfectly unfolded. But we have 
 shown, that all the phenomena of magnetic intensity, varia- 
 tion, and dip, are in perfect accordance with our views. 
 What more could be expected from any theory, than that it 
 be founded on facts, and that it should explain the phenome- 
 na ? Moreover, this theory explains a great variety of phe- 
 nomena in meteorology, hitherto involved in mystery. 
 
 170. Mr. Herschell observes, in his late beautiful work on- 
 natural philosophy, in reference to the problem of polarity, that 
 " the numerous experiments in electro-magnetism, show us 
 
t3T A NEW THEORY OF 
 
 that there is light, could only a certain veil be drawn aside." 
 We humbly trust, that we have in some measure, withdrawn 
 this veil, by showing the origin of atmospheric electricity, its 
 relations to caloric, and their unequal distribution in the 
 tropical and polar regions. 
 
 171 . We shall conclude with a quotation from Sir Hum- 
 phrey Davy. " The more the phenomena of the Universe are 
 studied, the more distinct their connection appears, the more 
 simple their causes, the more magnificent their design, and the 
 more wonderful the wisdom and power of their Author." 
 (Elements of Chemical Philosophy.) 
 
 POSTSCRIPT. The intelligent reader must have discovered a striking analogy 
 between the laws of gravitation, and those of cohesive, capillary, chemical, and 
 magnetic attractions. For example, that they all operate with a force inversely, 
 as the squares of the distance ; and that the same law is predicable of caloric and 
 electricity. ' 
 
 Sir Isaac Newton resolved "the action of large masses of matter into the actions 
 of their minutest particles or atoms; considering these particles.as centres of force." 
 Now if cohesive, capillary, chemical and magnetic attractions are owing to the 
 agency of caloric, as we have endeavored to prove and if they are only modifica- 
 tions of the cause of gravitation, it necessarily follows, that caloric is "the bond of 
 union among the heavenly bodies." (See Sec. 147, Part 7.) 
 
 We have shown (Section 6, Part 1.) that the attraction of caloric for pondera- 
 ble matter is inversely as the amount of its caloric. For example, the attraction 
 of caloric for frozen mercury, is greater than for fluid mercury it is also stronger 
 for ice than for water at the same temperature; because water contains 140 
 more latent caloric than ice. M. M. Du Long and Pettit have estimated the 
 specific caloric of all bodies having an equal number of atoms, to be the same 
 whether the atoms be larger or smaller and it has been demonstrated that an atom, 
 of gold, is four times as large as an atom of iron, which explains why the specific 
 gravity of gold, is four times that of iron and as its attraction for caloric is increas- 
 ed in proportion to the diminished quantity of caloric which it contains, its actual 
 gravitating force follows the same ratio. In other words, the gravitating power 
 of gold, is in proportion to the size of its atoms, and to the diminished quantity of 
 
TERRESTRIAL MAGNETISM. 135 
 
 . caloric between them while that of the lighter metals, stones, wood, furs, silks, 
 gasses, and all other bodies, is less in proportion to the increased quantity of speci- 
 fic caloric which fills their pores, and to the diminished size of their atoms. Is 
 this not the rationale of GRAVITATION 1 Does its power not increase at given dis- 
 tances, in proportion to the number and size of the ponderous atoms of different 
 bodies, and to the* diminished quantity of their specific caloric'? And does it not 
 follow from the above facts and reasonings, that the force by which the planets 
 and comets are attracted towards the sun, is proportional to the number and size 
 of their ultimate atoms, and to their respective distances from him ? 
 
 The following paragraph should be read after section 93, part I. : 
 An argument which proves still more conclusively than any we have em- 
 ployed, the identity of caloric and electricity, is deducible from the operations 
 of a common electrical machine. It has been a generally received doctrine, since 
 the days of Franklin, that in charging a Leyden jar, with a common electrical 
 machine, the igneous fluid was drawn from the earth and that a conducting 
 chain, or wire, from the rubber to the ground or floor was necessary. Dr. 
 Franklin thought that electricity was pumped up from the earth, by the revolu- 
 tions of the cylinder. Dr. Hare has recently demonstrated, (See American 
 Journal of Science, July, 1833,) that a battery may be charged as readily 
 when the machine is perfectly insulated, as when connected with the ground 
 by a conductor from which it is obvious, as we had long a^-o suspected, that 
 the electric fluid is obtained from the atmosphere and that it is nothing 
 more nor less, than the latent caloric of the atmosphere, forced out during its 
 condensation between the cylinder and rubber. Dr. Hare seems not to have 
 taken this view of the subject he thinks, that "the effect of the machine is 
 merely to transfer the fluid from one surface of the Leyden battery to another." 
 We are, however, greatly indebted to him, for correcting the above error, which) 
 for a long time, has greatly obscured the subject of electricity. 
 
APPENDIX. 
 
 THE following tables, constructed from the best authenticated 
 observations of different individuals for the last two hundred and 
 fifty years, down to the year 1818, were collected by Christian 
 Hansteen, Professor of Astronomy in the University of Norway, 
 and published a few years ago in his work on the Magnetism of 
 the Earth. We have copied them from the Edinburgh Philoso- 
 phical Journal, and from Sir David Brewster's Journal of Science. 
 
 In addition to what we have already said in the text on the 
 subject of magnetic variation, we shall present the reader with the 
 following observations of Professor Hansteen on the monthly, 
 daily, and hourly variations of the needle. 
 
 " In addition to its annual movement, the needle has likewise a 
 sensible movement from day to day, and even from hour to hour. 
 In Europe, it lies farthest to the east about eight or nine o'clock 
 in the morning, farthest to the west about one or two o'clock in 
 the afternoon ; it next travels back eastward till about eight or 
 nine o'clock in the evening, when it continues stationary for an 
 hour or two, or else makes a slight recoil towards the west; 
 during the night it commonly advances a little eastward, so that 
 about eight in the morning, it is found somewhat more easterly 
 than it was the preceding evening. 
 
 "The common daily movement about the summer solstice, is 
 nearly twice as great as about the winter solstice : at the former 
 season about -J-, at the latter 1 of a degree.* There is likewise a 
 regular monthly movement, such as that from the summer solstice 
 to the vernal equinox, the needle travels westward; eastward from 
 the vernal equinox to the summer solstice. 
 
 * See Section 122, Part II. 
 18 
 
138 APPENDIX. 
 
 " The regular daily movement is smaller near the equator, and 
 increases onward to the pole.* The needle's eastermost or west- 
 ermost position does not happen at the same instant, nor even at 
 the same hour, in places very distant from each other. Its west- 
 ermost position is reached in Iceland and Greenland, at from 
 eight to ten in the evening ; in Europe and the American United 
 States, from two to three in the afternoon ; in Sumatra about seven 
 in the morning, in St. Helena about eight. Its eastermost posi- 
 tion is attained in Europe and North America about seven or 
 eight in the morning, in Iceland and Greenland about nine or ten ; 
 in Sumatra about five in the evening, at St. Helena, about six 
 (or two.) On the north-west coast of America, the westermost 
 position seems to occur in the forenoon, the eastermost in the 
 afternoon." 
 
 " Those daily oscillations, in fine, appear to consist of four 
 movements, two directed eastward,, two westward. During the 
 continuance of the aurora borealis, the intensity of the earth's 
 magnetic force seems to grow -weaker, for which reason the 
 needle recedes from that magnetic pole where the ring of the 
 aurora is displayed." (See Edinburgh Philosophical Journal, 
 vol. IV., p. 119 and 20.) 
 
 From the numerous facts exhibited in these tables, the reader 
 will be prepared to draw his own conclusions. In a subsequent 
 part of this appendix, will be found, other tables, representing the 
 observations of Sir W. E. Parry, from the year 1819, up to tke 
 year 1824, also, tables of the dip or inclination of the needle in 
 different parts of the globe. All which, we offer as a general 
 guide to future observers. The latitudes and longitudes have 
 been omitted as they were in the Edinburgh Philosophical Jour- 
 nal, because of the space which they would occupy ; and as they 
 can be easily ascertained by a reference to Maps, Gazetteers, &c. 
 
 * See Section 119, Part II. 
 
APPENDIX. 
 
 139 
 
 TABLE I. Containing the Variation of the Needle, as observed 
 in Denmark, Norway, and Sweden. 
 
 NAMES o? PLACES. 
 
 Year of 
 Observa- 
 
 Magnetic 
 Variation. 
 
 NAMES OF PLACES. 
 
 Year of 
 Observa- 
 
 Magnetic 
 Variation. 
 
 
 tion. 
 
 
 
 tion. 
 
 
 Arendal, 
 
 1796 
 
 2021'W. 
 
 
 1774 
 
 1627'W. 
 
 Arboga, 
 
 1799 
 
 17 25 
 
 
 1775 
 
 16 37 
 
 Avestad, 
 
 1799 
 
 17 40 
 
 
 1775 
 
 16 20 
 
 ( 
 
 1763 
 
 19 20 
 
 
 1775 
 
 16 33 
 
 Bergen, < 
 
 1791 
 
 24 45 
 
 
 1775 
 
 16 26 
 
 c 
 
 1792 
 
 25 30 
 
 
 1775 
 
 16 27 
 
 Bommel Island, 
 
 1792 
 
 24 52 
 
 
 1776 
 
 16 27 
 
 Bessestcd, 
 
 1780 
 
 34 30 
 
 
 1776 
 
 16 30 
 
 IJhristiansund, 
 
 1768 
 
 16 30 
 
 
 1776 
 
 16 30 
 
 Christiansand, 
 
 1794 
 
 22 
 
 
 1776 
 
 16 28 
 
 
 1761 
 
 15 15 
 
 
 1776 
 
 16 32 
 
 
 1769 
 1816 
 
 16 45 
 20 15 
 
 
 1777 
 1777 
 
 16 20 
 16 39 
 
 . 
 
 1817 
 
 20 3 
 
 
 1779 
 
 17 5 
 
 Carlberg, 
 
 1799 
 
 17 5 
 
 
 1782 
 
 17 41 
 
 Carlscrona, 
 
 1716 
 
 11 15 
 
 
 1783 
 
 17 49 
 
 
 1649 
 
 1 30 E. 
 
 
 1784 
 
 17 42 
 
 
 1672 
 
 3 35 W 
 
 
 1784 
 
 18 
 
 
 1730 
 
 10 37 
 
 
 1785 
 
 18 7 
 
 1 
 
 1731 
 
 11 15 
 
 
 1786 
 
 18 9 
 
 
 1765 
 
 15 5 
 
 Copenhagen, 
 
 1792 
 
 18 23 
 
 
 1765 
 
 15 3 
 
 
 1793 
 
 18 15 
 
 
 1767 
 
 15 7 
 
 
 1806 
 
 18 25 
 
 
 1768 
 
 15 13 
 
 
 1807 
 
 18 21 
 
 
 1768 
 
 15 
 
 
 1808 
 
 18 22 
 
 
 1768 
 
 15 2 
 
 
 1809 
 
 18 22. 
 
 , 
 
 1768 
 
 14 50 
 
 
 1810 
 
 18 16 
 
 
 1768 
 
 14 56 
 
 
 1812 
 
 18 17 
 
 
 1769 
 
 15 30 
 
 
 1813 
 
 18 22 
 
 
 1769 
 
 15 29 
 
 
 1813 
 
 18 11 
 
 
 1769 
 
 15 34 
 
 
 1813 
 
 18 10 
 
 
 1769 
 
 15 22 
 
 
 1813 
 
 18 14 
 
 
 1770 
 
 15 32 
 
 
 1813 
 
 18 8 
 
 Copenhagen, 
 
 1770 
 
 15 32 
 
 
 1814 
 
 17 58i 
 
 
 1770 
 
 15 32 
 
 
 1814 
 
 17 56 
 
 
 1770 
 
 15 32 
 
 
 1814 
 
 17 56 
 
 
 1770 
 
 15 37 
 
 
 1815 
 
 18 6 
 
 
 1771 
 
 15 32 
 
 
 1815 
 
 18 3 
 
 
 1771 
 
 15 42 
 
 
 1815 
 
 18 5| 
 
 
 1771 
 
 16 2 
 
 
 1816 
 
 18 15i 
 
 
 1772 
 
 16 17 
 
 
 1817 
 
 18 5 
 
 
 1772 
 
 16 
 
 
 1817 
 
 17 55 
 
 
 1773 
 
 16 12 
 
 
 1761 
 
 13 50 
 
 
 1770 1 
 
 16 16 
 
 
 1769 
 
 15 25 
 
 
 1 / / O \ 
 
 16 17 
 
 
 1770 
 
 15 30 
 
 
 1773 
 
 16 22 
 
 
 1771 
 
 15 40 
 
 
 1773 
 
 16 9 
 
 Drontheim, 
 
 1772 
 
 16 6 
 
 
 1773 
 
 16 20 
 
 
 1773 
 
 16 40 
 
 
 1774 
 
 16 17 
 
 
 1774 
 
 16 46 
 
 
 1774 
 
 16 20 
 
 
 1775 
 
 16 58 
 
 
 1774 
 
 16 32 
 
 
 1776 
 
 17 30 
 
140 
 
 APPENDIX. 
 
 TABLE I. Continued. 
 
 NAMES or PLACES. 
 
 Year of 
 Observa- 
 tion. 
 
 Magnetic 
 Variation 
 
 NAMES OK PLACES. 
 
 Year of 
 Observa- 
 tion. 
 
 Magnetic 
 Variation. 
 
 f 
 
 1777 
 
 1745'W. 
 
 
 1718 
 
 537'W. 
 
 
 1778 
 
 17 50 
 
 
 1763 
 
 11 48 
 
 
 1779 
 
 18 
 
 
 1764 
 
 11 58 
 
 
 1780 
 
 18 
 
 
 1765 
 
 12 8 
 
 
 1781 
 
 18 24 
 
 
 1766 
 
 12 15 
 
 Drontheim, 
 
 1782 
 
 18 30 
 
 
 1767 
 
 12 21 
 
 
 1783 
 
 18 32 
 
 
 1768 
 
 12 28 
 
 
 1783 
 
 18 30 
 
 
 1769 
 
 12 33 
 
 
 1784 
 
 18 35 
 
 
 1771 
 
 13 4' 
 
 
 1786 
 
 19 
 
 Stockholm, 
 
 1772 
 
 13 4 
 
 Dyrefiords Haven 
 Fahlun, 
 
 1786 
 1799 
 
 42 41 
 18 45 
 
 
 1775 
 1777 
 
 13 20 
 13 56 
 
 Flekkeroe, 
 
 1783 
 
 19 29 
 
 
 1786 
 
 15 34 
 
 Fredericksborg, 
 
 1810 
 1694 
 
 18 50 
 8 30 
 
 
 1787 
 1800 
 
 15 17 
 
 16 20 
 
 Gottenburg, 
 
 1748 
 
 12 40 
 
 
 1811 
 
 15 52 
 
 Havnefiord, 
 
 1786 
 
 35 21 
 
 
 1817 
 
 15 36 
 
 Holmenahavn, 
 
 1786 
 
 43 9 
 
 
 1817 
 
 15 34 
 
 Hammerfest, - 
 
 1765 
 
 6 50 
 
 Salberg, 
 
 1746 
 
 9 
 
 Hustappen Island 
 Hvaloers Church, 
 
 1766 
 1768 
 
 7 
 16 25 
 
 Sala, 
 Soderbarke, 
 
 1790 
 1746 
 
 16 
 9 15 
 
 Hveen Island, 
 
 1672 
 
 2 35 
 
 Salo Bak, 
 
 1804 
 
 18 30 
 
 Helsingoer, 
 Hedmora, 
 
 1761 
 
 1748 
 
 14 
 9 10 
 
 Sadankyla, 
 Skiervoens Ch'ch 
 
 1776 
 1768 
 
 5 30 
 16 30 
 
 Jukasjerwi, 
 Kielvigs Church, 
 Karasjok, 
 Kongs winger - 
 
 1776 
 1766 
 1768 
 1779 
 
 11 30 
 5 30 
 6 50 
 17 30 
 
 Stromstad, 
 Sulen Island, - 
 Talvig, - 
 
 1804 
 1791 
 1766 
 1695 
 
 18 
 27 15 
 6 50 
 
 7 
 
 Kullens, ~ 
 
 1803 
 
 21 
 
 
 1736 
 
 5 5 
 
 K 6 ping, 
 Nya Kopparb'rg't 
 Kongsor, 
 Kusamo Church, 
 
 1799 
 1799 
 1746 
 1776 
 
 17 15 
 17 25 
 9 30 
 5 30 
 
 Tornea, 
 Utsjoki, -, - 
 
 1748 
 1767 
 1777 
 1748 
 
 7 30 
 8 50 
 11 45 
 3 30 
 
 Lindesness. 
 
 1605 
 
 7 10 E. 
 
 C 
 
 1718 
 
 5 37 
 
 Lofoeden Isles, 
 
 1608 
 1609 
 
 
 
 
 Upsal, - j 
 
 1740 
 1746 
 
 8 49 
 8 45 
 
 Lund Pfarrhof, 
 Lyderhorn, 
 Lindesberg, - 
 North Cape, - 
 Nora, 
 
 1785 
 1768 
 1746 
 1769 
 1799 
 
 19 SOW. 
 19 20 
 9 36 
 6 
 18 35 
 
 Uhma Capel, 
 Uranienburg, 
 
 Wardhus, 
 
 1762 
 1672 
 
 1748 | 
 1775 
 
 10 45 
 2 35 
 
 30 
 5 32 
 
 Norrberke, 
 
 1799 
 
 17 35 
 
 f 
 
 1748 J 
 
 30 
 
 Orebroe, 
 
 1799 
 
 17 7 
 
 Vadsoe, - 5 
 
 1 * *4O \ 
 
 1 
 
 Patrixfiord, 
 
 1772 
 
 33 30 
 
 I 
 
 1816 
 
 7 55 v 
 
 Rust Island, - 
 
 1613 
 
 4 8E. 
 
 Vangs Church, 
 
 1793 
 
 19 50 
 
 Stavanger, 
 Skudesness, - 
 
 1794 
 1613 
 
 22 26 W. 
 8 OE. 
 
 Vesteras, 
 Vinga Bak, - 
 
 1799 
 1804 
 
 17 50 
 19 
 
 Stadthuk 
 
 1768 
 
 19 10W. 
 
 
 
 
 
 1790 
 
 25 45 
 
 
 
 
APPENDIX. 
 
 141 
 
 TABLE II. Containing the variation of the Needle in Russia. 
 
 NAMES OF PLACES. 
 
 Year of 
 Observa- 
 tion. 
 
 Magnetic 
 Variation. 
 
 NAMES OF PLACES. 
 
 Year of 
 Observa- 
 tion. 
 
 Magnetic 
 Variation. 
 
 Awatscha Bay, 
 Sarrannoi Kamen 
 
 1805 
 
 1787 
 
 539'E. 
 7 40 ' 
 
 Neschin, - < 
 
 1729 
 
 1782 
 
 O'W. 
 
 
 Barnaul, 
 
 1770 
 1761 
 
 2 45 
 2 25W. 
 
 ^ 
 
 Orenburg, - 
 
 1769$ 
 
 3 30 
 3 20 
 
 Casan, 
 
 1805 
 
 2 2E. 
 
 Orsk, 
 
 1769 
 
 15 
 
 Catharinenburg 
 
 1761 
 
 1805 
 
 50 
 
 5 27 
 
 Orel, 
 
 1781 
 1726 
 
 9 
 3 15 
 
 Carchow, - 
 
 1783 
 1811 
 
 7 27W. 
 5 17 
 
 
 1727 
 1730 
 
 2 30 
 4 4 
 
 Cherson, 
 
 1782 
 
 10 10 
 
 
 1741 
 
 3 56 
 
 Caffa, - 
 
 1772 
 
 7 
 
 
 1755 
 
 4 30 
 
 Dmitrewsk, 
 Druia, 
 
 1771 
 1773 
 1773 
 
 5 49 
 6 30 
 10 40 
 
 Petersburg, - 
 
 1772 
 1774 
 
 1782 
 
 3 30 
 4 50 
 7 30 
 
 St. Elizabeth, - 
 
 1770 
 
 9 45 
 
 
 1784 
 
 8 13 
 
 Gluchow, 
 
 1770 
 
 5 30 
 
 
 1797 
 
 9 12 
 
 G-urief, - 
 
 1769 
 
 3 25 
 
 
 1805 
 
 U 0? 
 
 Gloubouca, 
 
 1615 
 
 18 
 
 
 1806 
 
 7 52 
 
 
 1768 
 
 5 15 
 
 
 1811 
 
 7 36 
 
 Jakutskoi, 
 
 1769 
 
 5 
 
 
 1812 
 
 7 16 
 
 
 1788 
 
 2 
 
 Perm, 
 
 1805 
 
 1 10 E. 
 
 [rkulsk, 
 
 1735 
 1735 
 
 1805 
 
 1 15 
 I 19 
 
 32 E. 
 
 Petropaulowska j 
 Petrosawodsk, 
 
 1779 
 1805 
 
 1785 
 
 6 19 
 5 20 
 5 9W. 
 
 Jarowslawl, - 
 
 1782 
 
 4 OW. 
 
 Ponoi, 
 
 1769 
 
 1 10 E. 
 
 Jenicola, 
 
 1785 
 
 7 15 
 
 Peczora, 
 
 1611 
 
 22 30W. 
 
 ( 
 
 1769 
 
 2 15 
 
 Pustozerskoi, 
 
 1614 
 
 20 
 
 Kola, - \ 
 
 1769 
 
 1 45 
 
 Revel, 
 
 1751 
 
 7 30 
 
 
 1769 
 
 1 45 
 
 Riga, 
 
 1750 
 
 8 
 
 [ 
 
 1769 
 
 1 45 
 
 Samara 
 
 1770 
 
 8 10 
 
 Krementschuk, 
 
 1770 
 
 8 
 
 Sietscha, 
 
 1770 
 
 9 15 
 
 [ 
 
 1735 
 
 2 
 
 Sisran, 
 
 1770 
 
 5 50 
 
 Krasnojarsk, <| 
 
 1735 
 1735 
 
 1 
 1 45 
 
 Selenginsk. - < 
 
 1735 
 1735 
 
 
 30 
 
 I 
 
 1735 
 
 1 30 
 
 ( 
 
 1735 
 
 2 45 
 
 Kiachta, - $ 
 
 1735 
 
 3 
 
 Saratow, 
 
 1773 
 
 3 28 
 
 
 1735 
 
 2 45 
 
 Sewastropol, - 
 
 1785 
 
 11 13 
 
 Kiow, 
 
 1773 
 
 9 15 
 
 Tscherkask, - 
 
 1770 
 
 5 50 
 
 Kaluga, - 
 
 1784 
 
 7 45 
 
 Tara, 
 
 1805 
 
 6 6E. 
 
 Kursk. - 
 
 1784 
 
 5 
 
 Tomsk, , - 
 
 1805 
 
 5 37 
 
 Kostroma, 
 
 1782 
 
 3 45 
 
 ( 
 
 1716 
 
 
 
 Kesloffor Koz- ( 
 lov, 1 
 
 1785 
 
 11 38 
 
 Tobolsk, - J 
 
 1761 
 1805 
 
 3 46 
 7 9 
 
 Lubny, - 
 
 1782 
 
 9 5 
 
 Tanbow, - 
 
 1784 
 
 5 45W. 
 
 Moscow, 
 
 1732 
 
 5 26 
 
 Umba, 
 
 1769 
 
 3 30 
 
 Mosdok, 
 
 1785 
 
 6 40 
 
 Ufa, 
 
 1769 
 
 1 30 E. 
 
 Nezshni Kovima 
 
 1787 
 
 14 40 E. 
 
 Ustkamenogorskoi , 
 
 1770 
 
 2 
 
 Nizni-Udinsk, ! 
 Nertschinsk, - 
 
 1735 
 1805 
 1735 
 
 3 15W 
 2 40 E. 
 3 OW 
 
 Wologda, - 
 Woronetz, - 
 Zarizin, 
 
 1785 
 1783 
 1770 
 
 3 52W. 
 
 8 
 4 50 
 
142 
 
 APPENDIX. 
 
 TABLE III. Containing the Variation of the Needle in Holland, 
 Prussia, the Netherlands, and Sivitzerland. 
 
 NAME* OK PLACKS. 
 
 Year of 
 Observa- 
 tion. 
 
 Magnetic 
 Variation. 
 
 NAMES OF PLACES. 
 
 Year of 
 Observa 
 tion. 
 
 Magnetic 
 Variation. 
 
 Antwerp, - 
 
 1600 
 
 9 0' E. 
 
 1 
 
 1801 
 
 2126'W 
 
 Amsterdam, - 
 Augsburg, - 
 
 1767 
 1772 
 1798 
 
 1> SOW. 
 16 40 
 18 26 
 
 Geneva, - \ 
 
 1802 
 1803 
 1804 
 
 21 27 
 21 18 
 21 13 
 
 " 
 
 1717 
 
 10 42 
 
 Grata, 
 
 1770 
 
 15 50 
 
 
 1717 
 
 10 52 
 
 Gottingen, - 
 
 1777 
 
 16 48 
 
 
 1724 
 
 11 45 
 
 Hague, 
 
 1782 
 
 20 16 
 
 
 1725 
 
 11 56 
 
 Inspruek, 
 
 1787 
 
 22 40 ? 
 
 
 1725 
 
 11 52 
 
 [ 
 
 1600 
 
 
 
 
 1751 
 1764 
 
 14 16 
 14 15 
 
 Konigsberg, - < 
 
 1628 
 1642 
 
 1 
 1 5 
 
 
 1770 
 
 16 9 
 
 I 
 
 1774 
 
 13 30 
 
 
 1773 
 
 16 48 
 
 Leipsic, 
 
 1749 
 
 13 
 
 
 1774 
 
 16 54 
 
 r 
 
 1776 
 
 19 48 
 
 
 1775 
 
 17 li 
 
 
 1785 
 
 19 44 
 
 
 
 16 42 
 
 Manheim, - < 
 
 1786 
 
 19 53 
 
 
 '1777 j 
 
 16 45 
 
 
 1787 
 
 20 2 ' 
 
 Berlin, 
 
 1777 
 
 16 42 
 
 I 
 
 1788 
 
 20 5 
 
 
 1778 
 
 16 45 
 
 Mittau, 
 
 1783 
 
 10 52 
 
 
 1779 
 
 1780 
 
 16 46| 
 16 48 
 
 Middleburg, - 
 
 1786 
 
 1788 
 
 21 14 
 21 56 
 
 
 1782 
 
 17 47 
 
 Nuremberg, - 
 
 1685 
 
 5 5 
 
 
 1783 
 
 17 51 
 
 
 1774 
 
 15 45 
 
 
 1784 
 
 17 57 
 
 
 1775 
 
 16 15 
 
 
 1785 
 1786 
 
 18 3 
 18 20 
 
 Prague, - 
 
 1781 
 
 1782 
 
 16 50 
 17 44 
 
 
 1787 
 
 17 44 
 
 
 A 786 
 
 18 9 
 
 
 1788 
 
 17 5 
 
 
 1787 
 
 17 20 
 
 
 1805 
 
 18 5 
 
 Rotterdam, - 
 
 1767 
 
 19 
 
 
 1805 
 
 17 57 
 
 C 
 
 1784 
 
 17 49 
 
 
 1805 
 
 18 2 
 
 Regensburg, - < 
 
 1785 
 
 19 1 
 
 ( 
 
 1782 
 
 17 20 
 
 ^ 
 
 1786 
 
 19 11 
 
 r> J 
 
 1784 
 
 17 41 
 
 
 1747 
 
 13 34 
 
 Bonne, - < 
 
 1787 . 
 
 18 1 
 
 
 1748 
 
 14 22 
 
 ( 
 
 1788 
 
 18 55 
 
 
 1749 
 
 14 45 
 
 { 
 
 1628 
 
 1 
 
 
 1750 
 
 14 30 
 
 
 1642 
 
 3 15 
 
 
 1752 
 
 14 37 
 
 Dantzic, - 
 
 1670 
 1682 
 1760 
 
 7 20 
 8 48 
 11 
 
 Tankermund, 
 Vienna, 
 
 1814 
 1638 
 1760 
 
 19 
 
 13 
 
 I 
 
 1811 
 
 13 48 
 
 
 1781 
 
 18 40 
 
 Dusseldorf, - 
 
 1783 
 
 20 
 
 
 1782 
 
 18 40 
 
 Dresden, 
 
 1797 
 
 18 30 
 
 
 1783 
 
 18 39 
 
 Freyberg, . - 
 Fr'kf't-on-Mayne, 
 
 1769 
 1774 
 
 15 40 
 16 32 
 
 Wurtzburg, - - 
 
 1784 
 1785 
 
 18 30 
 8 33 
 
 Franeker, 
 
 1771 
 1773 
 
 19 30 
 
 18 30 
 
 
 1786 
 1787 
 
 18 31 
 18 35 
 
 Geneva, 
 
 1797 
 1800 
 
 19 40 
 21 30 
 
 Zurich, 
 
 1762 
 
 15 15 
 
APPENDIX. 
 
 143 
 
 TABLE IV. Containing the Variation of the Needle as observed 
 in France. 
 
 NAMES OF PLACES. 
 
 Year of 
 Observa- 
 tion. 
 
 Magnetic 
 Variation. 
 
 NAMES OF PLACES 
 
 Year of 
 Observa- 
 tion. 
 
 Magnetic 
 Variation. 
 
 Antibes, 
 
 1682 
 
 340'W 
 
 
 1700 
 
 740'W 
 
 Bayonne, 
 
 1680 
 
 1 20 
 
 
 Nov. 
 
 8 12 
 
 Boulogne, 
 
 1767 
 1679 
 
 17 26 
 1 45 
 
 
 1701 
 
 Sept. 
 
 8 25 
 
 8 48 
 
 Brest, 
 
 1771 
 
 20 10 
 
 
 1702 
 
 8 48 
 
 
 1.798 
 
 25 30 
 
 
 Oct. 
 
 8 50 
 
 Calais, 
 
 168T 
 1767 
 
 4 30 
 19 30 
 
 
 1703 
 Dec. 
 
 9 
 9 6 
 
 Dieppe, - 
 
 1619 
 
 6 30 E. 
 
 
 1704 
 
 9 20 
 
 Dunkirk, - 
 
 1767 
 
 18 33W. 
 
 
 1704 
 
 9 20 
 
 Havre de Grace, 
 
 1767 
 
 1782 
 
 19 15 
 22 15 
 
 
 1705 
 July 
 
 9 25 
 9 30 
 
 Marseilles, - 
 
 1761 
 1798 
 
 18 
 20 55 
 
 
 Dec. 
 Dec. 
 
 9 35 
 10 
 
 St. Maloes, - 
 
 1681 
 
 2 
 
 
 1706 
 
 9 48 
 
 Montpellier, 
 Ushant Island, 
 
 1674 
 1776 
 1541 
 
 1 10 
 23 1 
 7 OE. 
 
 
 1707 
 1708 
 Dec. 
 
 10 10 
 10 15 
 10 15 
 
 
 1550 
 
 8 
 
 
 1709 
 
 10 40 
 
 
 1580 
 
 11 30 
 
 
 Dec. 
 
 10 30 
 
 
 1603 
 
 8 45 
 
 
 1710 
 
 10 50 
 
 
 1610 
 
 8 
 
 
 Dec. 
 
 10 50 
 
 
 1630 
 
 4 30 
 
 
 1711 
 
 11 
 
 
 1640 
 
 3 
 
 
 Dec. 
 
 10 50 
 
 
 1642 
 1659 
 
 2 30 
 2 * 
 
 Paris, 
 
 1712 
 Dec. 
 
 11 25 
 11 15 
 
 
 1660 
 
 1 
 
 
 1713 
 
 11 40 
 
 
 1664 
 
 40 
 
 
 Dec. 
 
 11 12 
 
 
 1666 
 
 
 
 
 
 1714 
 
 12 
 
 
 1667 
 
 15W. 
 
 
 Dec. 
 
 11 30 
 
 
 1670 
 
 1 30 
 
 
 1715 
 
 11 10 
 
 
 1680 
 
 2 40 
 
 
 1716 
 
 12 15 
 
 
 1681 
 
 2 30 
 
 
 Oct. 
 
 12 30 
 
 Paris, 
 
 1682 
 1683 
 
 2 30 
 3 50 
 
 
 Dec. 
 1717 
 
 12 30 
 12 45 
 
 , 
 
 1684 
 
 4 10 
 
 
 Dec. 
 
 12 40 
 
 
 1685 
 
 4 10 
 
 
 1718 
 
 12 30 
 
 
 1686 
 
 4 30 
 
 
 Dec. 
 
 12 30 
 
 
 1687 
 
 5 12 
 
 
 1719 
 
 12 30 
 
 
 1688 
 
 4 30 
 
 
 1720 
 
 13 
 
 
 1689 
 
 6 
 
 
 1721 
 
 13 
 
 
 1691 
 
 4 40 
 
 
 Oct. 
 
 13 
 
 
 1692 
 
 5 50 
 
 
 1722 
 
 13 
 
 
 1693 
 
 6 20 
 
 
 Nov. 
 
 13 
 
 
 1695 
 
 6 48 
 
 
 1723 
 
 13 
 
 
 1696 
 
 7 8 
 
 
 Dec. 
 
 13 
 
 
 1697 
 
 7 40 
 
 
 1724 
 
 13 
 
 
 1698 
 
 7 40 
 
 
 1725 
 
 13 
 
 
 1699 
 
 7 50 
 
 
 Oct. 
 
 13 15 
 
 
 Oct. 
 
 8 10 
 
 
 Dec. 
 
 13 15 
 
 
144 
 
 APPENDIX. 
 
 TABLE IV. Continued. 
 
 NAMBS OF PLACES. 
 
 Year of 
 Observa- 
 tion. 
 
 M agnetic 
 Variation 
 
 NAMES OF PLACES. 
 
 1 Year of 
 Observa- 
 tion. 
 
 Magnetic 
 Variation. 
 
 ( 
 
 1726 
 
 1345'W 
 
 
 Dec. 
 
 2041'W 
 
 1 
 
 1727 
 
 14 
 
 
 1779 
 
 20 31 
 
 
 1728 
 
 13 50 
 
 
 June 
 
 20 35 
 
 
 1729 
 
 14 10 
 
 
 July 
 
 20 33 
 
 
 1730 
 
 14 25 
 
 
 Aug. 
 
 20 40 
 
 
 1731 
 
 14 45 
 
 
 Aug. 
 
 20 31 
 
 
 1732 
 
 15 15 
 
 
 Nov. 
 
 20 35 
 
 
 1733 
 
 15 45 
 
 
 1780 
 
 20 35 
 
 
 1734 
 
 15 35 
 
 
 Mar. 27. 
 
 20 45 
 
 I ' 
 
 Dec, 
 
 15 40 
 
 
 May 5. 
 
 20 40 
 
 
 1735 
 
 15 45 
 
 
 16. 
 
 20 42 
 
 
 Oct 
 
 14 55 
 
 
 17. 
 
 20 49 
 
 
 1736 
 
 15 40 
 
 
 18. 
 
 20 42 
 
 
 Dec. 
 
 15 40 
 
 
 19. 
 
 21 4 
 
 
 1737 
 
 14 45 
 
 
 20. 
 
 20 49 
 
 
 1738 
 
 15 10 
 
 
 21. 
 
 20 45 
 
 
 Feb. 
 
 15 20 
 
 ^;" ; 
 
 22. 
 
 20 42 
 
 
 1739 
 
 15 30 
 
 
 23. 
 
 20 57 
 
 
 1740 
 
 15 45 
 
 
 24. 
 
 20 44 
 
 
 Dec. 
 
 15 30 
 
 
 25. 
 
 20 48 
 
 
 1741 
 
 15 40 
 
 
 26. 
 
 20 46 
 
 
 1742 
 
 15 4Q 
 
 
 27. 
 
 20 47 
 
 
 Sept. 
 
 15 10 
 
 
 28. 
 
 20 43 
 
 
 1743 
 
 15 10 
 
 
 29. 
 
 20 47 
 
 
 1744 
 
 16 15 
 
 
 31. 
 
 20 42 
 
 Paris, r -> - 
 
 1745 
 1746 
 
 16 15 
 16 15 
 
 Paris, 
 
 June 1. 
 
 2. 
 
 20 45 
 20 45 
 
 
 1747 
 
 16 30 
 
 
 3. 
 
 20 48 
 
 
 1748 
 
 16 15 
 
 
 4. 
 
 20 39 
 
 
 1749 ' 
 
 16 30 
 
 
 5. 
 
 20 49 
 
 
 1750 
 
 17 15 
 
 
 7. 
 
 20 39 
 
 
 1751 
 
 17 
 
 
 9. 
 
 20 39 
 
 
 1752 
 
 17 15 
 
 
 13. 
 
 20 48 
 
 
 1753 
 
 17 20 
 
 
 16. 
 
 21 4 
 
 
 1754 
 
 17 15 
 
 
 IS. 
 
 20 43 
 
 
 1755 
 
 17 30 
 
 
 19. 
 
 20 45 
 
 
 1757 
 
 18 
 
 
 22. 
 
 20 54 
 
 
 1758 
 
 18 
 
 
 24. 
 
 20 50 
 
 
 1759 
 
 18 10 
 
 
 25. 
 
 20 42 
 
 
 1760 
 
 18 30 
 
 
 26. 
 
 20 39 
 
 
 1765 
 
 19 
 
 
 27. 
 
 20 42 
 
 
 1770 
 
 19 55 
 
 
 28. 
 
 20 38 
 
 
 1771 
 
 19 50 
 
 
 30. 
 
 20 44 
 
 
 1772 
 
 20 12 
 
 
 July 3. 
 
 20 36 
 
 
 Nov. 
 
 20 2 
 
 
 5. 
 
 20 51 
 
 
 1773 
 
 20 4 
 
 
 7. 
 
 20 39 
 
 
 Apl. 
 
 20 
 
 
 8. 
 
 20 44 
 
 
 1774 
 
 20 17 
 
 
 Aug.. 16. 
 
 21 
 
 
 Aug 
 
 20 12 
 
 
 Sept. 19. 
 
 20 45 
 
 
 1777 
 
 20 27 
 
 
 21. 
 
 20 50 
 
 
 1778 
 
 20 37 
 
 I 
 
 22. 
 
 20 42 
 
 
APPENDIX 
 
 145 
 
 TABLE IV. Continued. 
 
 NAMES OF PLACES. 
 
 Year ot 
 Observa- 
 
 Magnetic 
 Variation. 
 
 NAMES OF PLACES. 
 
 Year of 
 Observa- 
 
 Magnetic 
 Variation. 
 
 
 tion. 
 
 
 
 tion. 
 
 
 
 Sept. 23. 
 
 2046'W 
 
 I 
 
 1798 
 
 2217'W 
 
 
 Dec. 19. 
 1781 
 
 20 56 
 20 47 
 
 
 1799$ 
 
 22 49 
 22 
 
 
 Jan. 27. 
 
 20 40 
 
 
 1800 
 
 22 12 
 
 
 Mar. 7. 
 
 20 47 
 
 
 1801 
 
 22 1 
 
 
 April 1. 
 
 20 59 
 
 
 1802 
 
 21 45 
 
 
 17. 
 
 20 50 
 
 
 1802 
 
 22 3 
 
 
 May 8. 
 
 20 51 
 
 
 1802 
 
 21 45 
 
 
 12. & 29. 
 
 20 51 
 
 Paris, 
 
 1803 
 
 21 59 
 
 
 June 23. 
 
 20 57 
 
 
 1804 
 
 22 5 
 
 
 Oct. 8. 
 
 21 3 
 
 
 1804 
 
 22 15 
 
 
 1782 
 
 21 1 
 
 
 1807 
 
 22 34 
 
 
 June 28. 
 
 21 16 
 
 
 1814 
 
 22 34 
 
 
 July 4. 
 
 21 12 
 
 
 1816 
 
 22 25 
 
 Paris, 
 
 1783 
 
 21 12 
 
 
 1817 
 
 22 17 
 
 
 June 23, 
 
 21 22 
 
 
 1818 
 
 22 21,6 
 
 
 Aug. 5. 
 
 21 27 
 
 
 1819 
 
 22 29 
 
 
 1784 
 
 21 27 
 
 Royan, 
 
 1680 
 
 1 20 
 
 
 Feb. 29. 
 
 21 24. 
 
 Toulon, 
 
 1682 
 
 3 45 
 
 
 1785 
 
 21 35 
 
 
 1747 
 
 15 10 
 
 
 1786 
 
 21 37 
 
 
 1748 
 
 15 
 
 
 June 21. 
 
 21 27 
 
 
 1749 
 
 15 10 
 
 
 1789 
 
 21 56 
 
 
 1750 
 
 16 5 
 
 
 1790 
 1790 
 
 22 
 21 52 
 
 Toulouse, - 
 
 1751 
 1752 
 
 16 
 15 45 
 
 
 1791 
 
 22 2 
 
 
 1753 
 
 16 45 
 
 
 1791 
 
 22 4 
 
 
 1754 
 
 16 40 
 
 
 1792 
 
 22 45 
 
 
 1755 
 
 15 
 
 
 1793 
 
 22 49 
 
 
 1756 
 
 15 45 
 
 TABLE V. Containing the Variation of the Needle, as observed 
 in Great Britain and Ireland. 
 
 NAMES OF PLACES. 
 
 Year of 
 Observa 
 tion. 
 
 Magnetic 
 Variation. 
 
 NAMES OF PLACES. 
 
 Year of 
 Observa- 
 tion. 
 
 Magnetic 
 Variation. 
 
 Bristol, - j 
 
 1666 
 1667 
 
 127'W 
 1 33 
 
 
 
 1745 
 1751 
 
 18 0' W. 
 19 
 
 ' 
 
 1813 
 
 24 22 17 
 
 
 
 1772 
 
 23 30 
 
 
 1814 
 
 24 22 48 
 
 Dublin, - < 
 
 
 1786 
 
 26 21 
 
 
 1815 
 
 24 27 18 
 
 
 
 1788 
 
 26 50 
 
 
 1817 
 
 24 42 14 
 
 
 
 1790 
 
 27 15 
 
 Bushey Heath, - 
 
 1818 
 
 24 45 11 
 
 
 
 1791 
 
 27 23 
 
 
 1819 
 
 24 41 41 
 
 r 
 
 1804 
 
 26 30 
 
 
 1820 
 
 24 39 16 
 
 ,-, ,. Oct. 29. 
 
 ( 1808* 
 
 27 31 49" 
 
 - 
 
 1820 
 1822 
 
 24 36 34 
 24 35 26 
 
 lm : \ Nov. 3. 
 bur S h > Sept. 29. 
 
 I 1809* 
 ( 1812* 
 
 27 35 10 
 
 28 8 
 
 
 
 
 [ July 9. 
 
 1 1823f 
 
 27 48 
 
 19 
 
 * According to Mr. James Jardine's observations. 
 f According to Professor Wallace's observations. 
 
146 
 
 APPENDIX. 
 
 TABLE V. Continued, 
 
 NAMES or PLACES. 
 
 Year of 
 Observa- 
 tion. 
 
 Magnetic 
 Variation. 
 
 NAMES OF PLACES. 
 
 Year of 
 Observa- 
 tion. 
 
 Magnetic 
 Variation. 
 
 Hermitage Hill,* 
 
 1823 
 
 27 O'W. 
 
 r 
 
 1795 
 
 2357' W. 
 
 
 1580 
 
 11 15E. 
 
 
 1796 
 
 24 
 
 
 1722 
 
 5 56i 
 
 
 1797 
 
 24 1 
 
 
 1634 
 
 4 6 
 
 
 1798 
 
 24 0,6 
 
 
 1657 
 
 OW. 
 
 
 1799 
 
 24 1,8 
 
 
 1665 
 
 1 22 
 
 
 1800 
 
 24 3,6 
 
 
 1672 
 
 2 30 
 
 
 1801 
 
 24 4,2 
 
 
 1692 
 
 6 
 
 
 1802 
 
 24 6,7 
 
 
 1723 
 
 14 17 
 
 
 1803 
 
 24 8,8 
 
 
 1745 
 
 17 
 
 
 1804 
 
 24 8,4 
 
 
 1745 
 
 17 
 
 
 1805 
 
 24 8,8 
 
 
 1746 
 
 17 10 
 
 
 1809 
 
 24 11,0 
 
 
 Dec. 18. 
 
 17 25 
 
 London, - 
 
 1814 
 
 24 16,7 
 
 
 1747 
 
 17 30 
 
 
 July 
 
 24 17,9 
 
 London - < 
 
 1747 
 
 17 40 
 
 
 Aug. 
 
 24 21,2 
 
 
 1748 
 
 17 40 
 
 
 Sept 
 
 24 20,5 
 
 
 1773 
 
 21 9 
 
 
 1815 
 
 24 17,8 
 
 
 1774 
 
 21 16 
 
 
 1816 
 
 24 17,9 
 
 
 1775 
 
 21 43 
 
 
 1817 
 
 24 17 
 
 
 1786 
 
 23 17 
 
 
 1818 
 
 24 15,7 
 
 
 1787 
 
 23 19 
 
 
 1819 
 
 24 14,8 
 
 
 1788 
 
 23 32 
 
 
 1820 
 
 24 11,7 
 
 
 1789 
 
 23 19 
 
 
 1821 
 
 24 11 18" 
 
 
 1790 
 
 23 39 
 
 
 1822 
 
 24 9 55 
 
 
 1791 
 
 23 36 
 
 
 1823 
 
 24 9 48 
 
 
 1792 
 1793 
 
 23 36 
 23 49 
 
 Plymouth, - j 
 
 unkn'n. 
 1733 
 
 13 24 E. 
 13 27 W. 
 
 
 1794 
 
 23 56 
 
 Stromness Harbor 
 
 1774 
 
 24 
 
 From the preceding tabl'es, it will be perceived that a remark- 
 able shifting of the variation in the North of Europe, has marked 
 different periods. For example, from the year 1718, when the 
 variation was 5 37' W., at Stockholm, until 1800, when it was 
 16 20', the westerly variation increased some years, however, 
 more than others ; but from 1800 until 1817, there was a slight 
 retrograde movement in the variation. The irregular shifting 
 of the variation at St. Petersburg, is still more obvious. In the 
 year 1726, the westerly variation was 3 15', while in 1727 it was 
 2 30', showing a retrograde or easterly movement three years 
 afterwards, it was 4 4' W. and eleven years later, it was 3 56', 
 showing another slight retrograde movement. In 1784, it was 
 8? 13', and in 1805, it was 11, but the next year it had shifted 
 backwards, or easterly, 3 48' from which it is evident, that the 
 
 * Near Leith, according to Mr. Andrew Waddell's observations. 
 
APPENDIX. 
 
 147 
 
 shifting of the Magnetic Variation has not the regularity or uni- 
 formity which belongs to revolutionary movements. 
 
 In the year 1580, the variation was 11 30' E., at Paris; while in 
 1666, it was nothing. From thattime until 1819, it advanced wester- 
 ly, but without much regularity sometimes remaining nearly sta- 
 tionary for many years. For more than a hundred years, while the 
 variation was easterly at Paris, the needle must have obeyed a 
 magnetic pole in the North of Asia, and not the American pole as 
 at present. The same is true in regard to the variation at London 
 during the same period. 
 
 TABLE VI. Containing the Variation of the Needle as observed 
 in Portugal, Spain, and Italy. 
 
 NAMES OP PLACES. 
 
 Year of 
 Observa- 
 tion. 
 
 Magnetic 
 Variation. 
 
 NAMES OF PLACES. 
 
 Year of 
 Observa- 
 tion. 
 
 Magnetic 
 Variation. 
 
 Aranjuez, 
 
 1798 
 
 19025'W. 
 
 r 
 
 1706 
 
 630'W 
 
 Alborne Island, 
 
 1733 
 
 14 12 
 
 
 1762 
 
 17 32 
 
 Braga, 
 
 1761 
 
 16 15 
 
 Lisbon, 
 
 1776 
 
 19 
 
 Brescia, 
 
 1676 
 
 4 OE. 
 
 I 
 
 1782 
 
 19 51 
 
 f 
 
 1724 
 
 5 25 W 
 
 Loretto, 
 
 1756 
 
 15 35 
 
 
 . 1769 
 
 17 15 
 
 Madrid, 
 
 1799 
 
 19 59 
 
 Cadiz, - - | 
 
 1769 
 1771 
 
 18 40 
 18 
 
 Malta, - < 
 
 1694 | 
 
 9 15 
 9 45 
 
 
 1776 
 
 19 42 
 
 ( 
 
 1708 
 
 10 25 
 
 Cape St. Vincent, 
 Cape St. Gatt, Sp. 
 
 1791 
 1733 
 1733 
 
 21 56 
 13 49 
 13 56 
 
 Minorca, C.'Mola, 
 Padua, - ) 
 
 1733 
 1725) 
 1730$ 
 
 14 34 
 13 
 
 CapeSt.Mary's,P. 
 
 1734 
 
 14 20 
 
 | 
 
 1770 
 
 16 20 
 
 f 
 
 Cape Finisterre, } 
 
 1589 
 1768 
 
 7 40 E. 
 21 4 W 
 
 
 
 1670 
 1681 
 
 2 15 
 5 
 
 C'peSt.Antonio,S. 
 
 1792 
 
 19 23 
 
 
 
 1695 
 
 7 30 
 
 Ferrara, 
 
 1677 
 
 2 
 
 
 
 1730 
 
 11 
 
 
 1733 
 
 13 38 
 
 
 
 1782 
 
 16 49 
 
 
 1761 
 
 17 11 
 
 Rome, 
 
 
 1783 
 
 16 49 
 
 
 1792 
 
 22 6 
 
 
 
 1784 
 
 16 54 
 
 f 
 
 1638 
 
 7 39 E. 
 
 
 
 1785 
 
 17 
 
 Lisbon, - | 
 
 1668 
 1683 
 
 SOW 
 3 
 
 
 
 1786 
 
 1787 
 
 17 4 
 
 17 7 
 
 I 
 
 1697 
 
 4 18 
 
 
 
 1788 
 
 17 12 
 
148 
 
 APPENDIX. 
 
 TABLE VII. Containing the Variation of the JYeecWe, as observed 
 in Turkey in Europe. 
 
 NAMES OF PLACES. 
 
 Year oi 
 Observa 
 lion. 
 
 Magnetic 
 Variation. 
 
 NAMES OF PLACES 
 
 Year of 
 Observa- 
 tion. 
 
 Magnetic 
 Variation. 
 
 Akiermann, 
 
 1771 
 
 925'W 
 
 r 
 
 1781 
 
 1645'W 
 
 Bender, 
 
 1772 
 
 9 45 
 
 
 1783 
 
 15 58 
 
 Bucharest, 
 
 1772 
 
 11 36 
 
 
 1782 
 
 15 36 
 
 r 
 
 1600 
 
 
 
 Ofen, - \ 
 
 1784 
 
 15 40 
 
 Constantinople, < 
 
 1625 
 
 2 
 9 
 
 
 1785 
 
 1787 
 
 15 48 
 16 26 
 
 [ 
 
 
 12 
 
 
 1788 
 
 16 36 
 
 TABLE VIII. Containing the Variation of the Needle as observed 
 in Asia and the adjacent Islands. 
 
 NAMES OF PLACES. 
 
 Year of 
 Observa- 
 tion. 
 
 Magnetic 
 Variation 
 
 NAMES OF PLACES. 
 
 Year of 
 Observa- 
 tion. 
 
 Magnetic 
 Variation. 
 
 Al'x'ndretta,Syria, 
 
 1694 
 
 1422'W 
 
 Celebes, Bonthain 
 
 1767 
 
 116'W 
 
 f 
 
 1612 
 
 13 40 
 
 Chaul, India, 
 
 1721 
 
 5 27 
 
 
 1612 
 
 12 40 
 
 
 1601 
 
 16 
 
 Aden, Arabia, \ 
 
 1674 
 
 15 
 
 
 1612 
 
 14 
 
 
 1723 
 
 13 50 
 
 
 1612 
 
 14 30 
 
 [ 
 
 1723 
 
 13 42 
 
 
 1620 
 
 14 20 
 
 Ava, India, 
 Aleppo, Syria, - 
 
 1689 
 1781 
 
 5 
 12 30 
 
 Cape Comorin, 
 India, 
 
 1680 
 
 1688 
 
 8 45 
 7 30 
 
 Alguarda, n'r Goa 
 Anjanga, India, 
 
 1722 
 1724 
 
 5 49 
 
 4 17 
 
 
 1723 
 
 2 51 
 2 48 
 
 3ab-el-Mandeb, 
 
 1723 
 1723 
 
 14 20 
 14 8 
 
 I 
 
 __ 
 
 2 50 
 3 9 
 
 Baixos de Cha- ( 
 gos Island, ( 
 3eit-el-Fakih, - 
 
 1610 
 1762 
 
 19 50 
 11 50 
 
 Ceylon, 
 Friar's Hood, 
 
 1722 
 1722 
 
 2 12 
 2 21 
 
 Bachian Island, 
 Amasane Bay, 
 
 1612 
 
 4 48 E. 
 
 Point de Galle < 
 
 1613 
 1723 
 
 13 24 
 2 46 
 
 
 1676 
 
 12 OW. 
 
 t 
 
 1723 
 
 2 45 
 
 
 1721 
 
 5 12 
 
 
 1731 
 
 3 
 
 Bombay, India, 
 
 1721 
 1722 
 
 5 16 
 5 7 
 
 Chandernagore, 
 
 1735 
 1743 
 
 2 
 1 20 
 
 
 1723 
 
 5 10 
 
 India, 
 
 1745 
 
 1 
 
 Banca Island, - 
 
 1791 
 
 
 
 
 1747 
 
 
 
 Balasore, India, 
 
 1680 
 
 8 20 
 
 
 1750 
 
 
 
 Do.Cape Palmiras 
 
 1722 
 
 3 33 
 
 
 1614 
 
 15 
 
 
 1722 
 
 4 5 
 
 
 1706 
 
 6 20 
 
 Oahcut, 
 
 1772 
 1690 
 
 4 9 
 2 25 
 
 Cochin, India, 
 
 1722 
 1722 
 
 3 34 
 3 53 
 
 Canton, 
 
 1722 
 
 1 30 
 
 
 1724 
 
 3 26 
 
 
 1722 
 
 5 40 
 
 
 1724 
 
 4 16 
 
 Carwar Bay, 
 
 1722 
 
 5 4 
 
 Daman, India, 
 
 1612 
 
 16 30 
 
 India, 
 
 1723 
 1724 
 
 5 8 
 5 32 
 
 Dabal, India, - j 
 
 1610 
 -1611 
 
 15 34 
 16 30 
 
 
APPENDIX. 
 
 149 
 
 TABLE VIII. Continued. 
 
 NAMKS OF PLACES. 
 
 Year of 
 Observa 
 tion. 
 
 Magnetic ' 
 Variation. 
 
 NAMES OF PLACES. 
 
 Year of 
 Observa- 
 tion. 
 
 Magnetic 
 Variation 
 
 ^erbent, Persia, 
 
 1712 
 
 12 O'W. 
 
 Mazeira Is. Arabia, 
 
 1613 
 
 2010'W 
 
 Darsina, Arabia, 
 
 1612 
 
 15 2 
 
 
 1723 
 
 13 34 
 
 Doy or Doa, Mo- 
 lucca Islands, 
 
 1613 
 
 5 20E. 
 
 Mocha, Arabia, 
 
 1769 
 1776 
 
 12 33 
 11 20 
 
 Brando, an Isl'd 
 near Japan, 
 
 1613 
 
 2 50 
 
 Mindanao, Cape 
 
 St. Augustin, 
 
 1767 
 
 1 45 E. 
 
 
 1609 
 
 16 W. 
 
 Nankin, China, 
 
 1685 
 
 OW. 
 
 
 1706 
 
 6 40 
 
 Nicobar, India, 
 
 1605 
 
 7 5 
 
 Goa, India, 
 
 1722 
 1723 
 
 4 57 
 5 13 
 
 Paliacate, India, j 
 
 1611 
 1613 
 
 13 15 
 13 10 
 
 
 1723 
 
 5 3 
 
 ( 
 
 1611 
 
 12 47 
 
 
 1724 
 
 5 41 
 
 Patapilli, India, < 
 
 1611 
 
 12 22 
 
 Gruadal Cape, 
 
 1613 
 
 17 15 
 
 \ 
 
 1613 
 
 13 50 
 
 Persia, 
 
 1616 
 
 18 
 
 Pondicherry, 
 
 1689 
 
 7 
 
 lainan Isl. China,. 1613 
 
 50 
 
 Princes Island, 
 
 1767 
 
 1 
 
 Hyderabad,* < 1fi(U 
 27th June, { | f 
 
 1 16.39E 
 
 near Java, 
 Pulo Condore, 
 
 1760 
 1620 
 
 54 
 1 
 
 f Bantam, 1609 
 
 3 OW. 
 
 Island, 
 
 1780 
 
 14 
 
 ava, < Batavia, \ , CQ 
 
 f 17uO 
 
 1 25 
 25 
 
 Pekin, 
 St. Paul's Island, 
 
 1755 
 1677 
 
 2 
 23 30 
 
 [Palimbano 
 
 1605 
 
 3 20 
 
 Roqucpiz, Island, 
 
 1610 
 
 23 30 
 
 spahan, Persia, 
 
 1787 
 
 7 30 
 
 Rogipore (Raja- ) 
 
 1722 
 
 4 58 
 
 riseh, - 1797 
 
 8 14 
 
 pur,) ) 
 
 
 
 norana Island, 
 
 IS07 
 
 4 13 
 
 Rasalgat Cpe. Arb 
 
 1613 
 
 19 20 
 
 a sic Cape, Per- 
 sia, 
 
 1616 
 
 19 20 
 
 c 
 
 Sually, - ; 
 
 1610 
 1611 
 
 16 40 
 16 30 
 
 tidda, Arabia, 
 
 1769 
 1776 
 
 11 52 
 12 55 
 
 I 
 
 Sunda Strait, 
 
 1612 
 1615 
 
 17 
 3 30 
 
 tasbin, Persia, 
 
 1787 
 
 7 33 
 
 Sinde, 
 
 1613 
 
 16 45 
 
 Cerguelen's Land 
 
 1776 
 
 27 44 
 
 Sinope, 
 
 1797 
 
 10 18 
 
 f 
 
 1685 
 
 4 45 
 
 f 
 
 1611 
 
 16 23 
 
 T Q- 
 
 1685 
 
 30? 
 
 
 1612 
 
 16 50 
 
 jouveau, Siam, <[ ,ggg 
 
 4 45 
 
 Surat, - I 
 
 1722 
 
 5 50 
 
 [ 1688 
 
 4 30 
 
 
 1723 
 
 5 59 
 
 jucepara Island, 1767 
 
 
 
 ( 
 
 1723 
 
 5 22 
 
 i 1616 
 
 1 30 
 
 Singanfu, China, 
 
 1689 
 
 3 17 
 
 Macao - < 1685 
 
 4 0? 
 
 Sumatra, 
 
 
 
 ( 1779 
 
 32 
 
 Achen, 
 
 1610 
 
 6 25 
 
 Madras, India, j 
 
 1722 
 1723 
 
 2 52 
 3 16 
 
 Marlborough ( 
 Fort, \ 
 
 1794 
 
 1 10 E. 
 
 Madura Island, 
 
 
 OOA 
 
 
 1795 
 
 1 8 
 
 near Java, 
 
 176o 
 
 ou 
 
 Priam an, - 
 
 1612 
 
 4 10W. 
 
 
 1722 
 
 5 24 
 
 
 1613 
 
 4 50 
 
 Mangalore, Ind. < 
 
 1722 
 1723 
 
 5 35 
 
 5 5 
 
 Tellicherry, Ind. 
 
 1722 
 1722 
 
 4 21 
 4 4 
 
 Masulipatam, In< 
 
 . 1610 
 
 12 22 
 
 Tiiz, 
 
 1613 
 
 18 30 
 
 Machian Island, ( 
 
 1612 
 
 4 12 E. 
 
 Tecu Island, - 
 
 1612 
 
 4 40 E. 
 
 near Gilolo, \ 
 MaldevischeCa- 
 
 1613 
 1605 
 
 3 28 
 17 W. 
 
 Xin-Yam, China, 
 Ula, China, - 
 
 1682 
 1682 
 
 OW. 
 1 40 E. 
 
 nal, 
 
 1722 
 
 4 16 
 
 
 * This is the mean of two observations made at the Camp near Hussain San- 
 gor, by Lieut. Col. Morison, and communicated to me by John-Robison, Esq. 
 
150 
 
 APPENDIX. 
 
 TABLE IX. Containing the variation of the JYVed/e, as observed 
 in Africa and the adjacent Islands. 
 
 NAMES or PLACES. 
 
 Year ot 
 Observa- 
 tion. 
 
 M agnetic 
 Variation. 
 
 NAMES OF PLACES. 
 
 Observa- 
 tion. 
 
 ?SS. 
 
 Alexandria, S 
 
 1638 
 1761 
 
 545'W 
 11 4 
 
 Comora Islands, 
 
 1611 
 
 13 O'W 
 
 Egypt, ' \ 
 
 1798 
 
 13 6 
 
 Angoxa, on c'st. 
 
 1721 
 
 19 12 
 
 ' 
 
 1678 
 
 1 OE. 
 
 of Africa, 
 
 1721 
 
 19 44 
 
 
 1754 
 
 8 6W. 
 
 
 1721 
 
 20 33 
 
 Ascension Isl'd,- 
 
 1768 
 1775 
 
 9 53 
 
 10 52 
 
 Anjouan, - 
 
 1722 
 1722 
 
 20 39 
 20 33 
 
 Accara, Fort ( 
 
 1806 
 1726 
 
 15 40 
 11,25 
 
 Mayotta, - 
 
 1722 
 1722 
 
 21 12 
 20 24 
 
 Guinea, \ 
 Angoxa, 
 
 1726 
 1611 
 
 11 53 
 12 1 
 
 Molalio, - 
 C ape Verd Islands 
 
 1611 
 
 15 20 
 
 Ab-dal-Curials. ( 
 
 1612 
 
 17 23 
 
 
 1725 
 
 4 5 
 
 W.of Sowtora { 
 Algiers, Barbary, 
 Azores Islands, 
 
 1723 
 1731 
 
 12 43 
 14 
 
 Porto Praya, St. 
 Jago, 
 
 1766 
 1766 
 1772 
 
 8 20 
 8 20 
 10 45 
 
 FayalBay, - j 
 Flores, 
 
 1589 
 1775 
 1600 
 
 3 5E. 
 22 7W. 
 
 
 Mayo, 
 
 1791 
 1725 
 1776 
 
 14 12 
 3 32 
 
 9 32^ 
 
 Marie, 
 
 1610 
 
 1 40 E. 
 
 Sal, 
 
 1610 
 
 3 30 E. 
 
 Bab-el-Mandeb, j 
 
 1723 
 1723 
 
 14 20W. 
 
 14 8 
 
 n~i~~ 
 
 1694 
 1761 
 
 12 15W. 
 12 25 
 
 Jaxos de Chagos, 
 3ourbon Isle of, 
 
 1610 
 
 19 50 
 
 Oairo, - < 
 
 1762 
 
 1798 
 
 11 40 
 12 
 
 Mascarenhas, 
 
 1614 
 
 22 48 
 
 Damietta, Egypt, 
 
 1694 
 
 12 30 
 
 St. Paul's Bay, \ 
 
 * 
 
 1722 
 1722 
 
 19 49 
 19 44 
 
 Doara, Ajan, 
 
 1611 
 1611 
 
 17 36. 
 17 20 
 
 Soobam, 
 
 1616 
 
 13 12 
 
 Prince Ed ward's 
 
 1776 
 
 26 15 
 
 C 
 
 1726 
 
 11 55 
 
 Island, 
 
 
 
 Cape Coast, - 
 Canary Islands, 
 
 1726 
 1726 
 
 1724 
 
 12 10 
 11 46 
 
 5 
 
 France, Isle of, 1 
 (Mauritius,) 1 
 
 1609 
 1722 
 
 21 
 
 18 46 
 18 39 
 19 7 
 
 Ferro, 
 
 1769 
 1802 
 
 17 30 
 19 55 
 
 Cape Good Hope 
 
 
 19 45 
 
 Lanzarote, - 
 
 1610 
 
 6 6E. 
 
 Cape 1' Agu- 
 
 1609 
 
 12 
 
 
 1727 
 
 6 58W. 
 
 illas, 
 
 
 
 Madeira,Fun- 
 chal, - ' 
 
 1766 
 1766 
 1771 
 1783 
 
 14 10 
 16 
 18 
 
 18 22 
 
 SaldanhaBay, j 
 Simon's Bay, j 
 
 1605 
 1614 
 
 1780 
 1791 
 
 30 E. 
 1 SOW. 
 22 16 
 23 40 
 
 
 1802 
 
 20 21 
 
 > .' '..' i 
 
 1614 
 
 1 45 
 
 Grand Canary, 
 
 1610 
 1769 
 
 6 6E. 
 15 43W. 
 
 
 1667 
 1675 
 
 7 15 
 
 8 28 
 
 
 1770 
 
 15 30 
 
 
 1687 
 
 8 30 
 
 Teneriffe, Sta 
 Cruz, 
 
 1776 
 1776 
 1785 
 
 14 41 
 15 55 
 15 52 
 
 Table Bay, 
 
 1699 
 1702 
 1706 
 
 11 
 12 50 
 13 40 
 
 
 1788 
 
 20 1 
 
 
 1708 
 
 14 
 
 
 1792 
 
 16 32 
 
 
 1721 
 
 16 25 
 
 
 1803 
 
 16 1 
 
 
 1724 
 
 16 27 
 
APPENDIX. 
 
 151 
 
 TABLE IX. Continued. 
 
 NAMES OF PLACES. 
 
 Year of 
 Observa 
 tion. 
 
 Vlagnetic 
 'ariation. 
 
 NAMES or PLACES. 
 
 \ ear of 
 Observa 
 tion. 
 
 Magnetic 
 Variation. 
 
 Cape Good Hope, 
 
 
 
 Madagascar, 
 
 
 
 
 1724 
 1752 
 
 618'W 
 9 
 
 Antongill Bay 
 
 1661 
 1761 
 
 230'W 
 8 
 
 Table Bay, 
 
 1768 
 1772 
 1775 
 
 9 30 
 20 26 
 21 14 
 
 Fort Dauphin, 
 Foul Point, - 
 
 1661 
 1761 
 1762 
 
 9 
 22 7i 
 16 45 
 
 
 1788 
 
 23 16 
 
 
 1600 
 
 16 
 
 
 1792 
 
 24 30 
 
 St. Sebastian, 
 
 1610 
 
 16 40 
 
 
 1804 
 
 25 4 
 
 Cape, 
 
 1722 
 
 19 1 
 
 | 
 
 1682 
 
 
 
 
 1722 
 
 18 36 
 
 Goree, - < 
 
 1769 
 
 12 15 
 
 
 1610 
 
 19 50 
 
 \ 
 
 1772 
 
 10 30 
 
 St. Mary's Isl'd. 
 
 1722 
 
 19 53 
 
 ( 
 
 1610 
 
 17 35 
 
 n'r Madagascar, 
 
 
 
 19 52 
 
 Guardafui/Cape < 
 
 1612 
 1721 
 
 17 34 
 11 11 
 
 Nosf-Gombi, an 
 
 z 
 
 19 25 
 20 
 
 1 
 
 1723 
 
 12 34 
 
 island near < 
 
 
 
 19 45 
 
 lermanas Isl'd. 
 
 1610 
 
 18 55 
 
 Madagascar, 
 
 
 
 19 5 
 
 n'rC.Guardafui, 
 
 1612 
 
 17 23 
 
 Salee Roads, - 
 
 1735 
 
 12 19 
 
 
 1600 
 1604 
 
 8 OE. 
 7 45 
 
 Sierra Leone, 
 
 1608 
 1725 
 
 1 50 E. 
 5 12W. 
 
 
 1610 
 1623 
 
 7 13 
 6 
 
 Sunken Rocks, ) 
 S.Lat_3148', $ 
 
 1606 
 
 21 
 
 
 1677 
 
 40 
 
 
 1611 
 
 16 
 
 
 1691 
 
 1 OW. 
 
 
 1612 
 
 17 22 
 
 St. Helena, Isl- 
 
 1724 
 
 7 30 
 
 
 1674 
 
 17 
 
 and of, 
 
 1764 
 
 11 38 
 
 
 1723 
 
 1H25 
 
 
 1768 
 
 12 47 
 
 Socotra, Island 
 
 
 
 11 36 
 
 
 1775 
 
 14 18 
 
 of, 
 
 
 
 11 38 
 
 
 1785 
 
 12 18 
 
 
 
 
 12 4 
 
 
 1789 
 
 15 30 
 
 
 
 
 11 57 
 
 
 1796 
 
 15 48i 
 
 
 
 
 12 20 
 
 
 1806 
 
 17 18 
 
 
 1776 
 
 8 6 
 
 Vladagascar, 
 
 
 
 St. Thomas, Isle C 
 
 1726 
 
 14 48 
 
 
 1607 
 
 15 30 
 
 of, \ 
 
 1726 
 
 14 32 
 
 
 1607 
 
 15 26 
 
 Tripoli, 
 
 1733 
 
 13 22 
 
 Augustin's 
 
 1610 
 
 14 50 
 
 Trinidad, Island C 
 
 
 
 Bay, 
 
 1611 
 
 15 11 
 
 S. Lat. 20 45,' < 
 
 1615 
 
 12OE. 
 
 
 1613 
 
 15 40 
 
 N. Long. 29 30,' ( 
 
 
 
 
 1721 
 
 23 48 
 
 
 
 
152 
 
 APPENDIX, 
 
 Account of the Scientific Observations made during the Expedition 
 
 under Captain Parry. 
 Taken from the Edinburgh Philosophical Journal. 
 
 1. Magnctical Observations. 
 
 As the measures of the variation and dip of the needle could be 
 taken only on icebergs and islands, out of the reach of the ship's 
 attraction, they are not so numerous as might have been expect- 
 ed; but they make up in importance for what they want in 
 quantity, and will be studied with much interest by the philoso- 
 phers of all countries. The following Table contains the whole 
 of the results given in Captain Parry's work, and deduced from 
 observations made principally by Captain Sabine. 
 
 Observations on the Variation of the Needle. 
 
 
 NORTH 
 Latitude. 
 
 West 
 Longitude 
 
 Variation 
 
 West. 
 
 
 1819, 
 
 
 
 
 
 June 19. 
 
 5949' 
 
 48 9' 
 
 4838'21' / 
 
 On ice. 
 
 26. 
 
 27. 
 
 63 58 
 63 44 
 
 61 50 
 61 59 
 
 61 11 31 
 
 60 20 12 
 
 On ice, 220 yards distant from 
 On ice. [ship. 
 
 30. 
 30. 
 
 63 26 
 63 29 
 
 62 9 
 
 62 8 
 
 61 50 12 
 60 55 48 
 
 j On ice, 200 yards distant. 
 
 July 15. 
 17. 
 
 70 29 
 
 72 
 
 59 12 
 59 56 
 
 74 39 
 
 80 55 27 
 
 On an iceberg. 
 On ice, 200 yards distant. 
 
 23. 
 
 73 5 
 
 60 Hi 
 
 82 2 40 
 
 
 23. 
 
 73 3 
 
 60 12i 
 
 82 37 30 
 
 > On ice, 250 yards distant. 
 
 24. 
 
 73 
 
 60 9 
 
 81 34 
 
 J 
 
 31. 
 
 73 31 
 
 77 22| 
 
 108 46 35 
 
 Possession Bay. 
 
 Aug. 3. 
 
 74 25 
 
 80 8 
 
 106 58 5 
 
 Iceberg. 
 
 r: 
 
 13. 
 
 72 45 
 73 11 
 
 89 41 
 
 89 22i 
 
 118 16 27 
 114 16 43 
 
 E. coast of Regent's Inlet. 
 On ice. 
 
 15. 
 
 73 33 
 
 88 18 
 
 115 37 12 
 
 E, coast of Regent's Inlet. 
 
 22. 
 
 74 40 
 
 91 47 
 
 128 58 7 
 
 Beach at Cape Riley. 
 
 
 
 
 EAST. 
 
 
 28. 
 Sept. 1. 
 
 75 9 
 75 3 
 
 103 44i 
 105 54 
 
 165 50 9 
 158 4 13 
 
 SE. point of B. Martin's Island. 
 On ice. 
 
 
 
 74 58 
 
 107 3 
 
 151 30 3 
 
 ' 
 
 6. 
 
 74 47 
 
 110 34 
 
 126 17 18 
 
 
 15. 
 
 74 28 
 
 111 42 
 
 117 52 22 
 
 
 Winter ) 
 
 . , , > 
 
 7447' 13' 
 
 110 49 
 
 127 47 50 
 
 
 Harbor $ 
 
 
 
 
 
 1820, 
 
 
 
 
 
 June 3. 
 7_ 
 
 IK 
 
 75 6 52 
 75 34 47 
 75 12 50 
 
 110 27 40 
 110 35 52 
 111 51 54 
 
 128 30 14 
 135 3 55 
 125 15 22 
 
 OnMelvill* Island, and during 
 an excursion into the inte- 
 rior of* it 
 
 12. 
 
 75 5 18 
 
 111 56 58 
 
 123 47 58 
 
 
 13. 
 
 75 2 37 
 
 111 37 10 
 
 126 1 48 
 
 
 15. 
 
 74 48 33 
 
 111 11 49 
 
 123 5 30 
 
 
 Aug. 5. 
 
 74 24 
 
 112 53 
 
 110 56 11 
 
 
 10. 
 
 74 26 
 
 113 48 
 
 106 6 38 
 
 
 18. 
 
 74 25 
 
 112 41 
 
 111 19 15 
 
 
 25. 
 
 74 27 
 
 112 11 
 
 114 34 45 
 
 
 Sept. 3. 
 
 71 16 
 
 71 18 
 
 91 28 32 
 
 W. coast of Davis' Strait. 
 
 
 70 22 
 
 68 37 
 
 80 59 17 
 
 Inlet called River Clyde. 
 
APPENDIX. 
 
 153 
 
 Observations on the Dip of the Needle. 
 
 j NORTH 
 | Latitude. 
 
 West 
 Longitude 
 
 Dip. 
 
 
 1819, 
 
 
 
 
 
 March 
 
 5131' " 
 
 8' 
 
 7033' 27" 
 
 Regent's Park, London. 
 
 June 26. 
 
 64 
 
 61 50 
 
 83 4 41 
 
 Ice, Davis' Strait. 
 
 July 17. 
 
 72 
 
 60 
 
 84 14 9 
 
 Ice, Baffin's Bay. 
 
 - 31. 
 
 73 31 
 
 77 22 
 
 86 3 7 
 
 Possession Bay. 
 
 Aug. 7. 
 
 72 45 15 
 
 89 41 
 
 88 26 71 
 
 E. coast of Regent's Inlet. 
 
 11. 
 
 72 57 
 
 89 30 
 
 88 25 17 
 
 On ice. 
 
 15. 
 
 73 33 
 
 88 18 
 
 87 35 95 
 
 N. Side of Barrow's Strait. 
 
 28. 
 
 75 10 
 
 103 44 
 
 88 25 58 
 
 B. Martin's Island. 
 
 30. 
 
 Sept. 6. 
 
 74 55 
 
 74 47 
 
 104 12 
 110 34 
 
 88 29 12 
 88 29 91 
 
 Ice, 400 yards distant from ship. 
 Beach, Melville Island. 
 
 11. 
 
 74 27 
 
 111 42 
 
 88 36 95 
 
 Melville Island. 
 
 1820, 
 
 
 
 
 
 July 18. 
 
 74 47 
 
 110 48 
 
 88 43 5 
 
 Observatory, Winter Harbor, 
 
 Sept. 17. 
 
 68 30 
 
 64 21 
 
 84 21 42 
 
 Ice, Davis' Strait. 
 
 - 28. 
 
 51 43 
 
 14 
 
 70 33 5 
 
 Near London. 
 
 " The change in the direction of the variation from Westerly to 
 Easterly, must have taken place about the 102d degree of west 
 longitude, and show.s that the expedition must at that point, which 
 they passed on the 27th of August, have been a few degrees to 
 the north of the Great Magnetic Pole. This conclusion agrees 
 very wonderfully with the position of this pole, as assigned by 
 M. Hansteen, who places it, in 1819, in 69 40' of North Lat., 
 (5 Q 23' to the south of the ships on the 27th August,) and in 90 
 of West Longitude." 
 
 " From the experiments made at Winter Harbor to determine 
 the variation in the magnetic force, it appears that the time of 
 vibration of Mr. Brown's dipping-needle decreased between Lon- 
 don and Winter Harbor in tKe ratio of 481 to 446 ; and conse- 
 quently, the force in the. direction of the dipping-needle appeared 
 to have increased in the ratio of 1.163 to 1." 
 
 " From the increase in the times of vibration of three horizon- 
 tal needles between Sheerness and Winter Harbor, the force 
 acting upon them appeared to have diminished in the ratio of 
 12.93 to 1 ; 13.23 to 1 ; and 13.83 to 1 ; the mean of which i 
 13.33 to 1." 
 
154 
 
 APPENDIX. 
 
 Observations on the Dip of the JVeecMe, made in different parts of 
 the World, 
 
 COLLECTED BY PROFESSOR HANSTEEN. 
 (Taken from the fourth volume of the Edinburgh Journal of Science.) 
 
 PLACES OF OBSERVATIONS. 
 
 Dip. 
 
 PLACES OF OBSERVATIONS. 
 
 Dip. 
 
 
 South. 
 
 
 
 Port du Nord 
 
 75 50' 
 
 St Gotthardt 
 
 66 22' 
 
 Port du Sud 
 
 70 48 
 
 Mont Cenis 
 
 66 22 
 
 Surrobaya in Java 
 Amboina 
 
 25 40 
 20 37 
 
 Ursern - 
 Altorf .... 
 
 66 42 
 66 53 
 
 ijima - - - - 
 
 9 59 
 
 Atlantic > 37 c 14'n.330'0" 
 
 67 30 
 
 Magnetic Equator in Peru 
 
 
 
 North. 
 
 Sea 538 52 3 40 
 Madrid - - - 
 
 67 40 
 67 41 
 
 Tompenda - 
 Loxa - 
 
 3 11 
 5 24 
 
 Tubingen - 
 Atlantic Sea 3852'n.340' 0" 
 
 68 4 
 68 11 
 
 Cuenca - 
 
 8 43 
 
 Ferrol - 
 
 68 32 
 
 ^luito 
 
 13 22 
 
 Paris - - - 
 
 69 12 
 
 St. Antonio 
 
 14 25 
 
 Gottingen ... 
 
 69 29 
 
 St. Carlos - 
 
 20 47 
 
 Berlin 
 
 69 53 
 
 Popayan 
 
 20 53 
 
 Carolath 
 
 68 21 
 
 Santa Fe de Bogata 
 
 24 16 
 
 Berlin . - 
 
 68 50 
 
 Javita - 
 
 24 19 
 
 Danzig 
 
 69 44 
 
 Esmeralda - 
 
 25 58 
 
 London 
 
 69 57 
 
 Carichana - 
 
 30 24 
 
 Ystad - - 
 
 70 13 
 
 St. Thomas 
 
 35 6 
 
 Schleswig 
 
 70 36 
 
 Carthagena 
 Cumana - - ' - 
 
 35 15 
 39 47 
 
 Copenhagen 
 Odense - 
 
 70 36 
 70 50 
 
 Mexico 
 
 42 10 
 
 Helsinburgh 
 
 70 52 
 
 Atlantic Sea 
 
 
 Kolding ... 
 
 *0 53 
 
 B.2046'n.L.41.26'w.F 
 
 41 46 
 
 Soroe - 
 
 70 57 
 
 11 0- 44 32 
 
 41 57 
 
 Friedrichsburg 
 
 70 59 
 
 12 34 33 14 
 
 45 8 
 
 Aarhuus - 
 
 71 13 
 
 1420 28 3 
 
 52 55 
 
 Aalborg - 
 
 71 27 
 
 _20 8 8 34 
 
 56 42 
 
 Odensala ... 
 
 71 39 
 
 21 36- 5 39 
 
 47. 49 
 
 Friedrichshaven 
 
 71 48 
 
 25 15 36 
 
 60 18 
 
 Gothenburg 
 
 71 58 
 
 Portici 
 
 60 5 
 
 Althorp ... 
 
 72 14 
 
 Neapel 
 
 61 35 
 
 Korset 
 
 72 24 
 
 Rome 
 
 61 57 
 
 Gtuistrum ... 
 
 72 27 
 
 Vesuv. Crater 
 
 62 
 
 Skieberg ... 
 
 72 29 
 
 St Cruz, TenerifFe 
 
 62 25 
 
 Elleoen 
 
 72 38 
 
 Valencia - - - 
 
 63 38 
 
 Helgeroae ... 
 
 72 39 
 
 Florence 
 
 63 51 
 
 Sorter - - , ; ;-, : 
 
 72 41 
 
 Atlantic Sea, 32 16' n. 2 
 
 
 Christiana - 
 
 72 34 
 
 52' w< 
 
 64 21 
 
 Ryenberg 
 
 72 45 
 
 Barcellona - 
 
 64 37 
 
 Bogstad 
 
 72 34 
 
 Marseille 
 
 65 10 
 
 Bogstadberg 
 
 73 13 
 
 Nimes 
 
 65 23 
 
 Nasoden 
 
 73 2 
 
 Mailand - 
 
 65 40 
 
 Barum ... 
 
 72 44 
 
 Montpelier 
 
 65 53 
 
 Bolkesjoe 
 
 73 15 
 
 
INDEX. 
 
 Attraction, the cause of, hitherto, not 
 understood, 7 
 
 Affinity, chemical, . philosophy of, still 
 in its infancy, 52 
 
 Aurora Borealis, one of the forms of 
 caloric, 42, &c. 
 
 Arnott, Dr., his theory of aerial con- 
 densation, 21 
 
 Arago, M., on the magnetism of rota- 
 tion, 126 
 
 Ampere, M., attributed magnetism to 
 electricity, 126 
 
 Antinori, Signer, drew sparks from the 
 permanent natural magnet, 127 
 
 Academy, American, memoirs of, re- 
 ferred to, 101 
 
 Barometer, an index of wind, but not 
 always of rain, and why, 79 
 
 Becquerel, M., his experiments on elec- 
 trical attractions, 17 
 
 Biot, M., ascended in a balloon, 109 
 describes two lines of no variation 
 on the eastern continent, 87 
 
 Brewster, Sir D., his doctrine of the 
 revolutionary movement of " cold 
 meridians" 68 untenable, and 
 why, 85 
 
 Barrington, Daines, his account of the 
 nearest approaches made to the 
 north pole, 70-71 anecdote con- 
 cerning the fears of Captain Wil- 
 son's crew, that the pole would 
 draw all the iron work out of the 
 ship, 88 
 
 Bowditch, Dr., on magnetic variation, 
 TOO and 102 
 
 Beccaria, was aware that lightning ren- 
 dered metals magnetic, 121 
 
 Boyle, Mr., found that amber, when 
 exposed to the sun's rays, attract- 
 ed light bodies, 127 
 
 Botto, Professor, of Turin, decomposed 
 water and acids by a current of 
 electricity, drawn from a horse 
 shoe magnet, 127 
 
 Barlocci, M., Increased the power of a 
 magnet, by exposing it to the solar 
 rays, 128 
 
 Brooks, Mr., on magnetic variation, 100 
 
 Caloric, a simple, imponderable ele- 
 ment, which pervades universal 
 nature, 7 the cause of cohesive, 
 capillary, and chemical attractions, 
 7 of evaporation, 12 of specific 
 gravity, 33 and 34 attracted by 
 mountains, clouds, &c., 12 the 
 cause of lightning, thunder, and 
 rain, 8 and 13 of atmospheric 
 currents, hurricanes, tornaddes, 
 whirlwinds, and water spouts, 22 
 and 23 of light, 37 of the auro- 
 ra borealis, 42 of life, 45 of 
 gravitation, 52 and 134 of polarity 
 
 Condensation, th.3 rationale of, 13 
 
 Chemical affinitv, experiments on, by 
 M. M. Becquerel and Pouillet, 17 
 
 C aid well, Dr., on life, 49 
 
 Carbonic acid gas whether a nega- 
 tive or positive poison, 51 
 
 Climate, how modified by glacial accu- 
 mulations in the polar seas, 71 
 and by the unequal distribution of 
 land and water, 60 and 105 not 
 owing to distant planetary and 
 cometary influence, 83 its inti- 
 mate connection with magnetic 
 phenomena, passim, in part II. 
 
 Cholera, its connection with the hygro- 
 metric and thermometric states of 
 the atmosphere, 82 and 83 
 
 Cook, Captain, his observations on the 
 polar ice of the southern hemi- 
 sphere, 97 
 
 Caucasus, Mount, ascended by M. 
 Kuppfer, 109 
 
 Christie, Mr., on magnetic variation, 
 109 
 
 Caulomb, M., his experiments before 
 the National Institute, showing 
 that all solid substances are more 
 or less magnetic, 120 demon- 
 strates mathematically the law 
 that magnetic attraction, like that 
 of gravitation, operates inversely, 
 as*the squares of the distance, 125 
 
 Davy, Sir H., referred chemical affini- 
 ties to the agency of opposite elec- 
 tricities, 7 his definition of elec- 
 
156 
 
 INDEX. 
 
 tricity 7 denies the materiality 
 of caloric, 39 mistook the attrac- 
 tion between electricity and pon- 
 derable matter, for an attraction 
 between opposite electricities, 32 
 
 Du Long and Petit their experiments 
 to determine the specific caloric of 
 different substances, 33 
 
 Daniell, Mr., on the different heights 
 of the tropical and polar atmo- 
 sphere, 24 on atmospheric cur- 
 rents, 25 on atmospheric electri- 
 city, 20 
 
 Darby, Mr., his account of the Euro- 
 pean climate for the last eighteen 
 centuries, 74 his estimate of the 
 comparative temperature east and 
 west of the Alleghany moun- 
 tains, 80 
 
 D6 Witt, Mr., his observations on 
 magnetic variation, 100 
 
 Electricity, atmospheric, one of the 
 forms of caloric, 14 its identity 
 with caloric, a key to unlock the 
 mysteries of nature, passim 
 
 Electro -magnetism, experiments in, by 
 Professors Moll, De la Rive, Ara- 
 go, Wollaston, Davy, Faraday, 
 Berschell, Christie, and other phi- 
 losophers, 121 
 
 Evolved during all combustions, ac- 
 cording to M. Pouillet's experi- 
 ments, 19 is never visible except 
 in a state of combination with 
 ponderable matter, 37 
 
 Emmet, Professor, drew electric sparks 
 from the natural or permanent 
 magnet, 127 
 
 Electricity two electricities, doctrine 
 of, controverted, 32 
 
 Franklin, Benjamin, Dr., observed that 
 different masses of vapor in differ- 
 ent states of electricity, attracted 
 each other, 13 
 
 believed that vapor was held in 
 
 a state of solution by electricity, 23 
 
 that the fusion caused by elec- 
 tricity was a cold fusion, or fusion 
 without heat, 29 
 -that electricity was formed in 
 
 the oceaa by the friction of salt 
 and water, 19 
 
 observed the connection of elec- 
 tricity with magnetism, 121 
 
 Field, General Martin, his observations 
 on the aurora borealis fh Ver- 
 mont, 44 
 
 Fusinieri, Dr., his electrical experi- 
 ments, 37 
 
 Fox, Mr., recommends compass boxes 
 to be made of non-conductors, 124 
 
 Faraday, Mr., drew electric sparks 
 from the natural or permanent 
 magnet, 127 
 
 experiments in electro-magnet- 
 ism, 121 
 
 Farrar, Professor, thinks we cannot 
 expect to discover the real s cause 
 of magnetic phenomena, 133 
 
 Forbes, Mr., drew electric sparks from 
 the natural or permanent mag- 
 net, 127 
 
 Fire, opinions of the Greek philoso- 
 phers concerning, 45 and 46 
 
 Fisher, Captain, on the accumulation 
 of ice in the Arctic Sea, 77 
 
 Galen, his sublime conceptions of 
 Almighty power, as displayed 
 throughout creation, 50 
 
 Gravitation, its cause, what, 52 and 
 its rationale, 134 
 
 Galvanic electricity, its relation to ca- 
 loric, 26, 27, 28 produced in the 
 same way that caloric is develop- 
 ed, 28 
 
 Gilbert, Dr., his theory of magnetism, 
 pronounced by Kepler the great- 
 est discovery in the annals of sci- 
 ence, 87 erroneous how it has 
 swayed the opinions of philoso- 
 phers, 88 
 
 Green, Professor, on electro-magnet- 
 ism, 124 
 
 Gibbs, Colonel, observed that the at- 
 tractive power of magnetic iron 
 ore is increased by exposure to the 
 sun and air, 128 
 
 Galvanism, one of the forms of caloric 
 developed by combustion or ox- 
 idation, 26 the earth a huge gal- 
 vanic pile, 27 
 
 Geology revolutions of the globe, 
 and consequent changes of cli- 
 mate, during ancient epochs, by 
 C. Lyell, 69 
 
 Greenland, New South, its probable 
 extent, and extreme coldness, 114, 
 115 
 
 Captain Morrell's account of it, 
 
 113 
 
 Gillet, Mr., his account of magnetic 
 variation in the United States, 106 
 
 Goodwin, Mr., on magnetic variation, 
 100 
 
 Hare, Dr., on the reciprocal attraction 
 of caloric and electricity, 29 
 
 Henry, Professor, his great magnet, 
 123 
 
INDEX. 
 
 157 
 
 Harris, Mr., on the interceptive influ- 
 ence of different substances in ar- 
 resting the action of a magnet, 
 125 
 
 Herschell, J. F. W., on light, and on 
 abstract science, 38, 39 
 
 Hansteen, Professor, his opinion of the 
 aurora borealis, 42 
 
 his observations on the varia- 
 tion, dip, and intensity of the mag- 
 netic needle, 62 
 
 found the intensity to vary in 
 
 ascending and descending the 
 round tower at Copenhagen, 110 
 
 found the magnetic intensity 
 
 greater during winter than sum- 
 mer, but that the dip was 15' great- 
 er during summer than winter, 
 108 his account of the mag- 
 poles, where situated. 106, 
 107 
 
 Hadley, Dr., his theory of winds, 24 
 
 Hippocrates, his theory in rejation to 
 fire, 46 
 
 Humboldt, Count, his experiments to 
 prove that the magnetic force in- 
 creased from the magnetic equator 
 to the poles ; fallacious, 89 esti- 
 mates the mean annual tempera- 
 ture at Cumberland House, to be 
 the same as that of central Rus- 
 sia, 99 
 
 Halley, Dr., considered the earth a hol- 
 low sphere, inclosing a minor mag- 
 netic globe, or terella, 84, 85 his 
 theory of magnetic variation, 84 
 his magnetic chart, very defective, 
 119 
 
 Inertia of matter, a philosophical ab- 
 surdity, 130 
 
 Jameson, Professor, his skepticism in 
 regard to the Dutch whalers, 61 
 
 Jannechen, M., on Russian cholera 
 observes its connection with the 
 thermometric and hygrometric 
 states of the atmosphere, 82 
 
 Jefferson, Mr., his observations on the 
 greater mildness of the American 
 climate at the present than in for- 
 mer times, 73 
 
 Kirwin, his formulas for estimating 
 polar temperatures erroneous, 59 
 
 Kuppfer, M., his experiments to deter- 
 mine the magnetic intensity on 
 mount Caucasus, 109 
 
 Light composed of common matter, 
 exceedingly expanded by caloric, 
 37 
 
 Lightning, its mechanical force, 41 
 one of the forms of caloric, 42 
 renders metals magnetic, 122 
 
 Lussac and Biot their experiments on 
 magnetic intensity, while ascend- 
 ing in a balloon, 109 
 
 Lyell, Charles, his theory of geological 
 revolutions during ancient epochs, 
 69, 70 
 
 Magnetism, terrestrial, basis of a theory 
 of, 56, 57 magnetic equator, the 
 true isothermal division of the globe 
 59 magnetic intensity, tables of, 
 
 89, &c. magnetic polarity, its 
 
 cause,63, &c. magnetic variation, 
 100, 101, & elsewhere every solid 
 substance more or less susceptible 
 of, 120 its extent as a science, 
 133 its intimate relations to calo- 
 ric, and to the science of universal 
 nature, passim magnetism of ro- 
 tation, M. Arago's experiments 
 on, 126 
 
 Matracci, Signor, electrified glass 
 plates with the solar rays, 35 
 
 Mayer, his estimate of polar tempera- 
 ture, 59 
 
 Morrell, Captain, his account of New 
 South Greenland, 11? 
 
 Mountains, their influence in deflecting 
 the needle from the direction of 
 the magnetic poles, 116 are cold- 
 er than the atmosphere at the 
 same elevation, and better conduc- 
 tors of caloric therefore attract 
 masses of atmospheric vapor 
 charged with caloric, 12 
 
 Needle, magnetic, its directive power 
 diminishes from the magnetic 
 equator to the poles, 87 & 117 not 
 influenced simultaneously by the 
 poles of both hemispheres, 118 
 horizontal at the magnetic equa- 
 tor, and why, 63 dips on advanc- 
 ing toward the poles, until the ho- 
 rizontal force ceases to operate, 
 when it becomes vertical, 62 its 
 polar end positive, and its tropical 
 end negative, 64 its polar end 
 directed to the centres of greatest 
 cold by calorific, or electrical cur- 
 rents, 59 influenced, probably, in 
 a mode analagous to that of the 
 vanes of our church steeples by 
 atmospheric currents, 118 
 
 Newton, Sir Isaac, maintains that there 
 must be some intervening medium 
 between the sun and planets, which 
 
159 
 
 INDEX, 
 
 holds them in their orbits, 52 Turner, Dr., his opinion of specific ca 
 
 
 that light and common matter are 
 convertible into each other, 56 
 
 Nye, Captain, his account of icebergs, 
 between England and the United 
 States, 82 
 
 Oerstedt, his experiments in electro- 
 magnetism, 121 
 
 Philip, Wilson, his experiments on 
 life, 47 
 
 Plato, held fire to be the principle of 
 life, 46 
 
 Pope, on the universal diffusion of the 
 vital principle, 50 
 
 Prince, William, his history of the vine, 
 72 
 
 Pole, north, warmer than the magnetic 
 pole, 61 
 
 magnetic, of great power in the 
 
 southern hemisphere, hitherto un- 
 known, 118 retrograde move- 
 ment of, appendix, temporary 
 
 between the American and Asiatic 
 
 Pythagoras, held fire to be the vivify- 
 ing principle of nature, 15 
 
 Pascalis, Dr., on the interceptive influ- 
 ence of the cocoons of the silk 
 worm, 126 
 
 Pixii, M., his electro-magnetic experi- 
 ments, 127 
 
 Read, Mr. observed that the upper ends 
 of lightning rods are negative, 
 and the lower ends positive, 64 
 
 Redfield, Mr., his theory of the verti- 
 genous motion of atmospheric 
 currents, 79 
 
 Ross, Captain, saw icebergs aground 
 in 1500 feet water, 71 thought 
 that the variation of the needle 
 was materially affected by heat 
 and cold, 117 
 
 Sabine, Captain, his magnetic experi- 
 ments and observations, 97 sup- 
 poses that there is an increase of 
 magnetic force, in passing from 
 the equator to the poles, 89 found 
 that the dip increased as the tem- 
 perature decreased, 97 
 
 Schuyler, General, on magnetic varia- 
 tion in the United States, 100 
 
 Saussure, M., found a decrease of 
 magnetic intensity on the Col du 
 Geant, near Mont Blanc, 109 
 
 Scheele, demonstrates that radiant heat 
 passes through air without heating 
 it, 66 
 
 Thomson, Dr., thinks the cause of 
 rain still involved in the deepest 
 obscurity, 20 
 
 loric, 53 
 
 Thunder, why less of during winter 
 thah summer, 26 
 
 Vapor, atmospheric, its bulk increases 
 1800 times in passing from the 
 fluid to the aerial state, 14 a 
 pound of, raises the temperature of 
 a pound of water, 1000 degrees, 
 14 precipitated in the form of 
 rain, snow, and hail, by the evo- 
 lution of its latent caloric, 13 is 
 attracted by mountains, water- 
 courses, &c., 12 its sudden con- 
 densation causes hurricanes, 
 whhlwinds, and water spouts 
 with a depression of the barome- 
 ter, 79, 80 
 
 Variation, magnetic, owing to different 
 centres of attraction in each hemi- 
 sphere, situated at unequal dis- 
 tances from the poles of the earth's 
 axis, 67 periodical variations 
 caused by annual, monthly, and 
 daily changes of temperature, 1 10 
 variation of magnetic intensity, 
 108 progressive variation, caus- 
 ed by the shifting of centres of cold, 
 100, 101-irregular variations, caus- 
 ed by thunder storms, great falls 
 of snow, violent winds, volcanic 
 eruptions, and the aurora borealis, 
 110 variation increases, as we 
 advance from the magnetic equa- 
 tor to the poles, 111 no variation 
 on many parts of the globe, and 
 why, 112 
 
 Varley, Mr., his observation on the 
 polarity of the balances of time- 
 piece?, 121 
 
 Volney, M., attributed the greater 
 quantity of electricity in the Uni- 
 ted States than in Europe, to the 
 dryness of the American atmo- 
 sphere erroneously, and why, 23 
 supposed that the south-west 
 wind of the Mississippi valley was 
 a portion of the tropical trade wind, 
 deflected by the Andes of Mexico, 
 79 that the climateof the Mis- 
 sissippi valley was milder than 
 that of the Atlantic States, 78 
 
 Western coasts warmer than eastern, 
 44, 98 
 
 Yelin, Dr., his conclusions from ther- 
 mo-magnetic experiments, 124 
 
 Zantesdeschi, M., increases the mag- 
 netic power of the loadstone by 
 exposing it to the sun's rays, 128 
 

 
ERRATA. 
 
 Page 43, ninth line from the bottom, read in, for beyond. 
 
 70* L,th S? t % third A n f e fr T b ttom for Lavosier, read Lavoisier. 
 70, fourth line from bottom, for Danes, read Daines. 
 74, fourth line from bottom, for renders, read render. 
 89, in the note, second line from bottom, for was, read were 
 
 
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