os oI iy ind ie Ae, iid L&E. Phit.Mag. Voi 9. Pla.) > ART CE AT =» EE ANE ws: NCIS TAAV UE Res BARON VON ZAC I, Lirector Of Feedlbs07r ALOL'Y Of ICECELG. E iF, o Litter of the \stronomical Correspondence.” Printed. by Graf he Saree — THE LONDON anv EDINBURGH PHILOSOPHICAL MAGAZINE AND : JOURNAL OF SCIENCE. CONDUCTED BY SIR, DAVID BREWSTER, K.H. LL.D.F.R.S. L. & EB. &e. RICHARD TAYLOR, F.L.S.G.S. Astr.S. Nat.H. Mose.&c. AND RICHARD PHILLIPS, F.R.S. L. & E. F.G.S. &c. “Nec aranearum sane textus ideo melior quia ex se fila gignunt, nec noster vilior quia ex alienis libamus ut apes.” Just. Lrrs. Monit. Polit. lib. i. cap. 1. VOL. 1x: NEW AND UNITED SERIES OF THE PHILOSOPHICAL MAGAZINE, ANNALS OF PHILOSOPHY, AND JOURNAL OF SCIENCE. JULY—DECEMBER, 1836. LONDON: PRINTED BY RICHARD TAYLOR, RED LION COURT, FLEET STREET, Printer to the University of London. SOLD BY LONGMAN, REES, ORME, BROWN, GREEN, AND LONGMAN; CADELL; BALDWIM AND CRADOCK; SHERWOOD, GILBERT, AND PIPER 5 SIMPKIN AND MARSHALL; WHITTAKER AND CO.; AND S. HIGHLEY, LONDON:— BY THOMAS CLARK, AND ADAM AND CHARLES BLACK, EDINBURGH; SMITH AND SON, GLASGOW ; HODGES AND M ARTHUR, DUB- LIN; AND G, W.M. REYNOLDS, PARIS, Tuer Conduetors of the London and Edinburgh Philosophical Magazine and Journal of Science beg to acknowledge the editorial assistance rendered them in the publication of the present volume by their friend Mr. Epwarp Wittram Bray ey, F.LS., F.G.S., Librarian to the London Institution. December \st, 1836. CONTENTS. NUMBER LI.—JULY, 1836. Mr. H.F. Talbot’s Facts relating to Optical Science. No.III. 1 Dr. H.S. Boase’s Remarks on Mr. Hopkins’s “‘ Researches in Bivgsical Geglosy”. 130.) ssa a eat Mea ss elo 06 4 Rev. E. Craig’s Remarks on Microscopic Chemistry ........ 10 Mance’ot the Parvest-biss 220). 3u 20 ae FANS ea 15 Dr. H. Johnson on the Divergence of Plants, and its Analogy to the lrritability of Animalsso36U8 26 05.05. Seok ES 17 Mr.W. 8. B. Woolhouse on the Theory of Vanishing Fractions, ia eply toi brofessor Young's. yalis agoe sit al) isl Ue 18 Prot. T. Graham on the Water of Crystallization of Soda-alum 26 Prof. Sir W. R. Hamilton’s Second Theorem of Algebraic Eli- mination, connected with the Question of the Possibility of resolving, in finite Terms, Equations of the Fifth-Degree .. 28 Dr. D. E. Riippell’s Observations on the FossilGenera Pseudam- monites and Ichthyosiagonites of the Solenhofen Limestone, contained in a Letter to R.I. Murchison, Esq............. 32 Mr. C. T. Beke on the former Extent of the Persian Gulf, and on the Non-identity of Babylon and Babel ; in Reply to Mr. Macter (ennLmaemy is \. ee Oi es co OL oT) POU POR 34 Letter from Baron von Humboldt to His Royal Highness the Duke of Sussex, K.G., President of the Royal Society of London, on the Advancement of the Knowledge of Terre- strial Magnetism, by the Establishment of Magnetic Sta- tions and corresponding Observations ................ + 42 Prof. Schoenbein of Hale on a peculiar Voltaic Condition of Iron; ina Letter to Mr. Faraday: with further Experi- ments on the same Subject, by Mr. Faraday ; communicated faa wetterito Mr Phillips)... 6.40.5 hte Aes: 53 Notice of the Magnetic Action of Manganese at low Tempera- tures, as stated by M. Berthier ; in a Letter from Mr. Fara- Re ee hays RNa inn sind WAIN Sako Mee So, ele UA a bie 65 Proceedings of the Zoological Society .................. 66 — at the Meetings of the Royal Institution .,...... 71 + Cambridge Philosophical Society ...... 71 On the feeble Attraction of the Electro-magnet for small Par- ficles of Iran.at short Distances «2. 0062..000. oes 006. cle. 72 Observations on the Solar Eclipse of May 15, 1836; and on the Aurora. Borealis of April 22 (2000.00.02 0..0%600 0080 73 British Association for the Advancement of Science........ 74 Meteors observed in Indiain 1832. .........00.0e ui ceees 74 M. Dufresnoy’s Analysis of Plombgomme ................ 75 On the Action of lodine on Organic Salifiable Bases........ 76 Ona New Mode of Analysis of closely aggregated Minerals... 76 On some New Combinations of Carbohydrogen or Methylene 77 pa the Periodide of Irom +. ny sag denial above Mee 4 79 iv CONTENTS. Page Meteorological Observations made at the Apartments of the Royal Society by the Assistant Secretary; by Mr. Thomp- son at the Garden cf the Horticultural Society at Chiswick, near London; and by Mr. Veall at Boston..........+--- 80 NUMBER LII.—AUGUST. Rev. W. Ritchie on the Cause of the remarkable Difference between the Attractions of a Permanent and of an Electro- magnet on Soft Iron at a Distance ...............---+- 81 Remarks on the Rev. J. H. Pratt’s Demonstration of a Propo- sition in the Mécanique Céleste .....2..5. 0 ee ask 84: Mr. J.D. Smith on the Hydrates of Barytes and Strontia.... 87 Mr. J. G. Children’s Notice respecting Dr. Ehrenberg’s Collec- tions of dried Infusoria, and other microscopic Objects.... 90 Prof. J. R. Young's concluding Remarks on the Theory of Vanishing, Fractions) 252.2) (9. GN es Us 92 Mr. J. Nixon’s Heights of Whernside, Great Whernside, Rum- ble’s Moor, Pendle Hill, and Boulsworth,............... 96 Mr. J.W. Lubbock on a Property of the Parabola...... ... 100 Mr. E. Rudge on the Position of the South Magnetic Pole .. 104 Mr. G. J. Knox and the Rev. T. Knox on Fluorine ........ 107 Mr. G. Bird on certain new Combinations uf Albumen, with an Account of some curious Properties peculiar to that Sub- Stanners) ty; ae) Se tS Ie Sas ids Se ee 109 Rev. Baden Powell’s Remarks on the Formula for the Disper- sion. of Light. (concluded. sini utr ee. Reuss Agra ee 116 Mr. F. W. Mullins on certain Improvements in the Construc- tion of Magneto-electrical Machines, and on the Use of Caoutchouc for Insulation in Voltaic Batteries .......... 120 Letter from Mr. Faraday to Mr. Brayley on some former Re- searches relative to the peculiar Voltaic Condition of Iron re- observed by Professor Schoenbein, supplementary to a Letter to Mr. Phillips,,in the last: Numbetie. ab. wee eeeseceeenes eee (81.) This relation c = ab reduces the expressions (76.)...(79.) to the following, f = —a', ] er te We an 82 gh+i= ab+a@b’—4a'd, ( a) Zi = Ad; orseceeeeee J and thereby reduces the condition (75.), that is, the product of the three conditions (66.) (67.) (68.), to the form —a’—3a b—a@?+5a°d=0, woe (83.) which gives either or else G4+3.4° 4-0? = Sidy sceserscrsceeees (85.) and therefore, by (80.), either BE =O), Ceotawes RIAL veo (601) or else 5D = B?. A CCONDOSCOC ACC: (61.) Thus, when we set aside these two particular cases, we see by (45.), that under the circumstances supposed in the enun- ciation of the theorem, the function /(x)—gq # vanishes, for every value of « which makes the polynome 2° + Ba? + Dx+E vanish; and that therefore if we set aside the third and only remaining case of exception, namely, the case in which the 32 Dr. Ruppell on the Fossil Genera Pseudammonites proposed equation of the fifth degree has two equal roots, and in which consequently the condition (62.) is satisfied, the function f(a) must be of the form (59.); which was the thing to be proved. — Corollary.—Setting aside the three excepted cases (60.) (61.) (62.), the coefficients of the equation (50.) of the fifth degree in y will be expressed as follows, B= -Q'2.B,.. Di 'Q’? D,;, «EL = Qe oat(GG.) and if we attempt to reduce it to De Moivre’s solvible form, by making DPBS 6. Ses Smee ee we find ‘ QAO Ra oa that is, QU Say ometey cs cheras eal ee ee so that the relation between y and 2 reduces itself to the form Wee eER SED ae LE Oa), uel... ate) which can give no assistance towards resolving the proposed equation (58.) of the fifth degree in z. Observatory, Dublin, June 11, 1836. IX. Observations on the Fossil Genera Pseudammonites and Ichthyosiagonites of the Solenhofen Limestone, contained in a Letter to R. 1. Murchison, Esq., V.P.R.S., §c. By D.E. Rouere.t, M.D., of Frankfort.* Dear Sir, I SEND you herewith the few words you requested me to draw up concerning the fossils I wish to exhibit at the Geological Society. In a paper which I published in 1829, I ventured to ex- press my opinion upon the generic character of two fossils, fragments of which are commonly met with at Solenhofen, and in other calcareous strata of formations of similar age. Having met with some of these fossils in what I considered to be a more than usually perfect condition, I was led to adopt * Communicated on the part of the Author by Mr. Murchison, who takes this method of laying before the public the notice, which would have been read before the Geological Society, at its last meeting of this ses- sion, had not the letter of Dr. Riippell been missent. The fossils alluded to were exhibited. Mr. Murchison is convinced that this small fragment will be read with interest as coming from the pen of the distinguished traveller whose researches have thrown so much light on the physical geo- graphy and natural history of Nubia and Abyssinia, and Ichthyosiagonites of the Solenhofen Limestone. 33 my present ideas of the animals to which they belonged. I perceived that the forms which naturalists had united in one genus under the name of Trigonellites, Tellinites, Ichthyosia- gonites, and Lepadites, (words which are all synonymous,) be- longed really to two distinct genera. One of these fossils is not unfrequently found with an Ammonite-like shell, but which has only an apparent likeness to the true Ammonite, for it has no internal septa. In many of these Ammonite-like shells there are found, near to their opening, two calcareous plates resembling in appearance a bivalve shell. These must in my opinion have belonged to the anima] which inhabited the Ammonite-like shell, and may have served as a kind of operculum to it, or perhaps as an organ for mastication, I formed this opinion by observing that whenever these two fossils, apparently so dissimilar, are found near one another, the right-hand side of the bivalve-like shell is uniformly of the same length as the largest diameter of the external whorl of the Ammonite-shaped fossil. Besides, I perceived that the two parts which form this kind of operculum are in some other points perfectly distinct in structure from any living bi- valve shells, namely, the valves are not connected with liga- ments, and have a sharp edge on the side where they unite; the other margin, opposite to this sharp edge, is a thick cal- careous mass. The laminz which are on the convex side of these opercula have not, like other bivalves, a central point round which they increase, but are placed somewhat in a dia- gonal position, a circumstance which is never met with in a real bivalve shell. Since I wrote the paper alluded to, I have observed a con- siderable number of these fossils, all of which confirmed the constant proportion of the diameters of the bivalve and ammonite-like shell when found together. I remain, there- fore, confident that they belonged to one animal, forming quite a new type in the series of Mollusca, for which I have proposed the name of Pseudammonites. Some naturalists have expressed the idea that the finding both these fossils so frequently together was a consequence of the animal of the Ammonite-like shell having eaten the other. But if so, how does it happen that there is so con- stantly a fixed proportion in their relative sizes, and why are more than one pair never found in each shell? Besides, had the one served as food for the other, why are the apparent bivalve shells always in a fine state of preservation, lying parallel to each other? The other fossil, in shape somewhat similar to these oper- cula, I consider to be an internal shell met with in a large Third Series. Vol.9. No. 51. July 1836. ¥F 34 Mr. Beke on the former Extent of the Persian Gulf, elliptic muscular mass. 1 have exhibited before the Geological Society one of the specimens which suggested to me this idea, and the sight of it illustrates those facts which I have ex- plained in my work better than a more lengthened descrip- tion. That a bivalve may have been an interior shell is rather an unexpected exception to all known rules of conchology. It is, however, not a theory of mine, but is borne out by plain facts. Tothis singular genus I gave the name of Ichthyosia- gones (1829). It has been changed since to Aptychus, I know not why; and again, both the types of Pseuwdammonites and Ichythyosiagones have been mixed together as species belong- ing to the same genus, more particularly in a paper printed last year in the memoirs of the Linnzean Society of Normandy, by Mr. Eudes de Longchamp, who proposed a new name for the genus “ Munsteria” | The object I have had in presenting to the meeting of the Geological Society some of the fossils I have spoken of, is to call the attention of English geologists to these shells, that a new investigation may be made by some conchologist, in order to reexamine the question whether these fossils are to form the types of two distinct genera, according to my observations; or if they are to be considered as of one genus, but specifically differing from each other, which seems to be the opinion of those persons, who are influenced in drawing their conclusion from the apparent similarity of the external form of these shells. Yours very truly, D. E. Ruppet. X. On the former Extent of the Persian Gulf, and on the Non- identity of Babylon and Babel; in Reply to Mr. Carter. By C. T. Bexe, Esg., F.S.A. [Continued from page 515, and concluded.] ON the subject of the unlikelihood that Babel would, in the earliest post-diluvian ages, have been built in the lowlands of the Euphrates (supposing them to have existed), Mr. Car- ter observes that ‘no allusion is made to his answer that the cities and settlements of a hot climate, and more particularly those of an early people, are of necessity fixed in such places.” In a former paper of mine* I stated that a portion of Mr. Carter’s arguments, which I then combated, was ‘founded upon the assumption that society in the time of Noah existed in a state of infancy as regarded its culture and knowledge;” he having remarked in the paper to which that was a reply +, * Lond, and Edinb. Phil. Mag., vol. iv, p. 28). + Ibid., p. 182. and on the Non-identity of Babylon and Babel. 35 that “navigation zn early society is usually performed in boats made of a single tree.” In his answer*, however, that gen- tleman says, ‘“* Mr. Beke has here mistaken my meaning. I have not expressed any opinion respecting the general culture and knowledge of mankind at that period. My remark was confined to their navigation only.” Under these circumstances I was desirous of avoiding, if possible, anything which might bring us into discussion respecting the state of “early society ;” especially as it was manifest, from more than one expression in Mr. Carter’s second paper, that his opinion and mine were not at all likely to coincide. But as it is necessary that I should refer to the subject, I must be permitted to say that I do not consider the instance adduced from the evidence of Col. Chesney of the villages of the half-savage residents on the banks of the Euphrates, which are frequently washed away by the stream, as at all analogous to the cztzes—not merely ‘inclosed lands,” or ‘small villages,” or “little settlements,” —of mankind in the post-diluvian ages. As I have in the third chapter of my Origines Biblice explained at length my views in connexion with this point}, I will merely remark that the nearest analogy to the earliest post-diluvians is pro- bably to be found in the European settlers in the New World, both people having sprung from a previous civilized and arti- ficial state of society. Now we see that even in the tropical portions of the Americas, where they have quite as great a ‘‘notion of the value of water” as the inhabitants of the East can possibly have, although for the purposes of foreign com- merce (which the earliest post-diluvians had not,) they have in some cases fixed upon situations like that of the deadly New Orleans, yet these offsets from the Old World have not, “‘ heedless of all the good reasons to the contrary, chosen for their settlements every such impracticable spot they could find.” But is there not an entire fallacy in the argument as to the alleged value of water in hot climates? The value of water in such climates is, properly speaking, principally of an artificial character, arising from the scarcity of that element. In those cases in which it is to be procured in plenty, the general habits of the people show that the real value is not so great as it is in more temperate regions. Of course it is not intended to be denied that water has a considerable real value in the former countries also; but if it be on account of that value (for so I un- derstand Mr. Carter’s argument, ) that the people dwelling near * Lond. and Edinb. Phil. Mag., vol. v. p. 244. + See also a paper entitled “ Views in Ethnography,” &c., published in Jameson’s New Edinburgh Enionon nent Journal, vol. xviii. pp. 285—296, in which some of my opinions on this topic are yet further elucidated. 4 F2 36 Mr. Beke on the former Extent of the Persian Gulf, the Euphrates are induced to erect their habitations in “ im- practicable spots,” where they are constantly liable to be washed away, should we not find the inhabitants of Mesopo- tamia generally settled on the banks of the two rivers instead of being dispersed over the interior, and ought we not likewise to see the people of Arabia flocking to the shores of the Euphra- tes, and employed in “ following their villages afloat to arrest the materials of their dwellings,” instead of remaining in their unwatered deserts? As to the mere erection of cities in plains, by the sides of rivers, and even in marshy situations, this is no peculiarity whatever of hot climates, but is equally preva- lent even in the coldest. When opportunities occur, settle- ments are, in all countries, usually made on the banks of ri- vers; but then they are not in the first instance founded from choice in impracticable spots, but are placed on the higher grounds, where they can enjoy all the benefits of the supply of water without being liable to the tides and ordinary floods; it being afterwards only, as population increases, that the buildings are extended over the lower lands, from which the waters have been banked out. Mr. Carter asserts, however, that “ the earliest settlements on record were, in fact, fixed in such places ;” and he in- stances the cities of Egypt, those of the vale of Siddim, and also Nineveh in particular; which last city, he says, was built “in the lowlands of the Tigris, a valley eight or ten miles broad, and where the floods were .so great that of old it was like a pool of water,” referring to Nahum, ii. 8. as an authority for the fact. I regret to be obliged to observe that he has altogether mistaken the meaning of this text. In our authorized version (which alone he would seem to have consulted,) it is unquestionably said, ‘ But Nineveh is of old like a pool of water;” but by this expression our venerable translators evidently intended, not a natural, but an artificial pool, as in 2 Kings, xx. 20. Neh. iii. 15. Eccl. ii. 6. and many other places, where the same expression occurs: and this, in fact,—or a fish-pond in particular, as in Cant. vii. 4.—is the real meaning of the word MD7A*, which is used by the prophet with reference to the immense popu- lation of Nineveh :—“ that great city, wherein were more than six score thousand persons that could not discern between their right hand and their left hand}.” ‘The comparison of tos 7t oe > . S| Shed . * The Arabic ;¢ , has the same signification. Jn its primitive meaning ? ae 5 it is, a reservoir of water at which the camels kneel (TD. badach, to wre drink : literally, therefore, a kneeling-place. + Jonah iy. 11. and on the Non-identity of Babylon and Babel. 37 the city may be either to a pool (reservoir) full of water, or to a fish-pond swarming with fish: the context shows that the general idea of fulness cannot be mistaken :—“ But Nineveh is of old [full or swarming] like a pool of water ; yet they shall flee away: stand, stand; but none shall look back......she és empty, and void, and waste*.” As regards the “cities of the plain,” it may be perfectly true that Jordan “ overflowed all his banks in the time of harvest,” without its thence following that those cities were affected by the inundation any more than Jericho, and the other cities which were, and still are, erected along the valley of that river. On the subject of Egypt, the opinion is already expressed at length in my Origines Biblice, that the Mitzraim of Scrip- ture was nowhere within the valley of,the Nile: it becomes unnecessary, therefore, that I should here say anything upon this particular point. But leaving this quite out of the ques- tion, we find from the earliest writer of profane history, that even within Egypt itself, the natives—a totally distinct people (I may just remark,) from the Mitzrites of the north, in the neighbourhood of Canaan,—came originally from the higher lands of the south, and that it was only “ as their country be- came more extensive that some remained in their primitive places of residence, whilst others migrated to a lower situation ; whence it was that the Thebaid went formerly under the name of Egypt t.” Independently therefore of “all the good reasons to the contrary”, the opinion is unfounded,—for what evidence we have is directly opposed to such an opinion,—that “ the earliest people on record chose for their settlements every such impracticable spot they could find.” On separate grounds it is yet contended, that the Babel of Genesis was actually built in the lowlands of the Euphrates, for that “Isaiah xxiii. 13. seems distinctly to identify Nim- rod’s Babel and Babylon,” from which text it is inferred that ‘‘ the Assyrian Nimrod founded Babel, formed into a social community the remnant of the people scattered and broken at the Dispersion, and the Assyrian of later days set up the towers and raised up the palaces thereof;” and it is subsequently argued as follows: ‘ As Shinar must have embraced no ver extensive range, and Nimrod’s Babel (or Babylon) and the * Diodati’s Italian translation represents the idea of the original far bet- ter than our English version : “ Or Nineve é stata, dal tempo che ¢ in essere, come un vivaio d’ acque : ora fuggono essi : fermatevi, fermatevi; ma niuno si rivolge..... Ella é votata, e spogliata, e desolata.” + Euterpe 15. 38 Mr. Beke on the former Extent of the Persian Gulf, Babylon of the prophets were in it, that we have here two places of the same name,—both moreover built in the very infancy of society, and both by ‘the Assyrian,’ is an inference not sanctioned by true historical construction.” But upon what construction, I would venture to inquire, is the former part of this text of Isaiah, “ the Assyrian founded it,” to be referred to “the Assyrian Nimrod,” and the latter portion of the same text, “ they set up the towers thereof,” to be ap- plied to “the Assyrian of later days”? And again, upon what construction is the epithet the Assyrian” given to Nimrod, who, according to Mr. Carter’s own interpretation of Gen. x. 10, was no Assyrian at all, but a foreigner who founded an intrusive monarchy in the land of Asshur ? In citing this text, * Behold the land of the Chaldeans: this people was not, till the Assyrian founded it for them that dwell in the wilderness: they set up the towers thereof, they raised the palaces thereof, and he brought it to ruin,” (This last portion of the verse is omitted to be quoted,) Mr. Carter says, “ No one can doubt that this refers to the celebrated Babylon.” Unfortunately, it happens that a very great many do doubt it, among whom it will be sufficient to name R. Jonathan ben Uzriel, the translator of the Peshito, Jerome, Theodosion, Saadias, Jarchi, and Kimchi, without enumera- ting a whole host of modern translators and commentators. In fact, Gesenius says that the last three portions of this verse are, almost unanimously, referred zo the destruction of Tyre by the Chaldeans*. As rendered in our authorized version (agreeing with Diodati) the meaning is not all obvious; but our translators could certainly never have intended to refer it (as Mr. Carter reads their words,) merely to the foundation of Babylon, or else what is the meaning of the last portion of it, ‘and he brought it to ruin” ? Mr. Carter does not, indeed, cite these words, but it is impossible to detach them from those which precede them; and I apprehend that gentleman would find a difficulty in showing their applicability to the founder of Babylon, whether that founder were Nimrod “in the in- fancy of society,” or “ the Assyrian of later days +.” * “ Die drei letzten Versglieder beziehen sich fast ohne Widerspruch auf die Zerstorung von Tyrus durch die Chaldier.”— Commentar. u. d. Jesaias; in loc. + In explanation of this passage it may be allowed me to remark, that the “towers” have generally been understood to be the war-towers of the be- sieging Chaldeans, and the “ palaces” to be those of Tyre which were, either (according to Saadias and Theodosion,) “raised (or roused) up” with affright or tumult through the siege, or (according to the Targum of Jonathan, the Vulgate, Jarchi, and Kimchi,) demolished by the enemy. I have for several years past had this very difficult and still unintelligible text and on the Non-identity of Babylon and Babel. 39 The greatest weight of authority unquestionably is for re- ferring the former half of this verse to the foundation of the Chaldean Babel or Babylon by the Assyrians ;—not, however, by any one individual, “the Assyrian,” but VW (Asshir), that is, the people of Asshur, or the Assyrian nation generally. Yet this is so far from aiding Mr. Carter’s opinion as to that city’s having been “a settlement of the earliest antiquity,” ‘made in the very infancy of society,” that it proves directly the contrary; for if the Babel of Genesis “ was not till the Assyrians founded it,” it is manifest that the Assyrians must already have existed as a nation, and that some time—pro- bably a considerable time: ‘*...this people was not till the Assy- rians founded it,’—had first elapsed. And not merely so, but it would also seem completely to establish the non-identity of Babel and Babylon; for (as Mr. Carter himself observes, ) “why was Babel” said in Gen. x. 10. to be “only the begin- ning of his kingdom, if we are not to understand that it was Nimrod who also builded Nineveh”? But if $0, it follows that Babel must have been erected before he “ went out into Assyria” ; whilst, on the other hand, the prophet tells us that the Chaldean Babel “ was not till the Assyrians founded it”— in other words, that it did not exist until after the establish- ment of the Assyrian Empire by Nimrod. Without however placing entire dependence upon this argument, on account of the darkness of the text of Isaiah, I must most distinctly assert, that this text does not (nor indeed does any other throughout the sacred volume,) in the slightest manner connect the two cities: the whole that can be inferred from it with respect to the age of Babylon is, that that capital was already in the prophet’s time a great flourishing city. It is from the Jews of the Captivity alone that we derive the pre- valent erroneous notion with respect to the identity of the Babel of Genesis with the far more recent Babylon (Babel). From the similarity of the names of the two cities and the existence in the latter of the famed tower of Belus, they (per- haps not unnaturally,) fell into the error of imagining them to be the same; and hence arose all the fables respecting the tower of Babel, for which not the slightest ground exists in the pages of Scripture. But that Babylon could not have been founded near the time of Nimrod—that in fact it did not exist until a comparatively late period, must assuredly be the only under my consideration, and I am willing to regard it, on the whole, as an authority in favour of my hypothesis as to the late foundation of Babylon, although I must, at the same time, confess thatI am far from being satisfied with any particular interpretation of it which has yet been given. 40 Mr. Beke on the former Extent of the Persian Gulf, inference which is to be drawn from the circumstance that— whilst Assyria (Asshur) is mentioned in the very earliest por- tions of the particular history of the Israelites and their imme- diate progenitors*, and is brought into direct connexion with the history of the kingdom of Israel.in or before the time of Jeroboam II.+, when Nineveh had “ of old” been a great and populous city,—Babylon itself, a city nearer to Canaan than Nineveh, and indeed almost in the road between them, is not even mentioned until some time afterwards, although Shinar was known to the Israelites from the earliest period {. And it is most worthy of remark that even when Babylon is first referred to in the scriptural history, it is merely as one of the places from which the king of Assyria brought inhabitants to repeople the country of the captive Israelites §, and as the city where the same monarch carried Manasseh king of Judah into captivity ||. It is true that Babylon is men- tioned a short time previously to the latter of these two events, in the time of Manasseh’s father 4, as having had its own ru- ler; but the comparison of the whole scriptural history evinces that the kings of Babylon were Assyrian viceroys, and not in- dependent sovereigns :—that this was actually the case is ex- pressly recorded by Alexander Polyhistor **. Upon the hypothesis of the distinction between Babel and Babylon, and of the late foundation of the latter city, the scriptural history, as connected therewith, becomes quite in- telligible; which otherwise it certainly is not. We can also fully understand how Herodotus, in mentioning the Assyrian empire, should describe Babylon merely as one of its great cities, which only “became the royal residence after the de- struction of Nineveh ++.” In entire accordance with the same hypothesis is that historian’s statement that the Assyrian Se- miramis (whom he makes to have preceded Nitocris only five generations, ) ‘ raised certain mounds [at Babylon]...éz// when the whole plain was subject to inundations from the river tf ;” and yet more particularly so is that of Megasthenes, who tells us that ‘from the beginning all things were water, called the * See Gen. xxv. 18. Numb. xxiv. 22, + Compare Jonah iii. 2. et seq., and 2 Kings xiv. 25. t See Josh. vii. 21: the expression, which in our authorized version is rendered “a Babylonish garment,” is in the original qWaw VAS (ad- déreth Shinhér), “a garment (mantle) of Shinar.” § See 2 Kings xvii. 24. || 2 Chr. xxxiii. 11. q Isa. xxxix. 1. ** Euseb. Arm. Chron. 42, in Cory’s Ancient Fragments, 2nd Edit. pp- 61, 62. tt Clio, 178. tt Clio, 184. and on the Non-identity of Babylon and Babel. 41 sea, and that Belus caused this state of things to cease, and appointed to each its proper place, and surrounded Babylon with a wall *.” - As to the supposition that “‘ Shinar must have embraced no very extensive range,” there is not the slightest ground for it. Like Asta—which name was gradually extended from a small portion of Lydia, first to Asia Minor, and then to an entire quarter of the globe,—and many other names of coun- tries, it may well have had very different applications at dif- ferent times; and in the latter portions of the Scriptural hi- story the same name was probably given to the whole country beyond the Euphrates, of the north-western portion of which the early Shinar was only a small division. I have at present to add but little on the geological portion of the subject}. Were the “power of the Euphrates, Tigris, and neighbouring streams to form new lands and expel the ocean,” a solitary case and opposed to the-usual course of nature, Mr. Carter might justly characterize it as “ extraor- dinary,” and might even be excused for imagining it to be “supposed”; but seeing that all rivers on the face of the earth under similar, or even yet less advantageous circum- stances, do actually possess this power{, it would indeed be extraordinary if these rivers alone were to be excepted from the rule. Even an instance of the formation of rock within the limits of the most recent fluviatiie deposits is furnished us * Tlevrae psy c& choyijs vowe sivas, IcAccoey xeAcomevyv. Byrov 0 oQex wadoul, xoony suadotw amroveiuavta, xal BaBvawve relyer repicarciv. Euseb. Prep. Evan. lib. 10. in Cory’s Ane. Frag. p.45. It is deserving of attention that Megasthenes further states that when Nebuchadnezzar re- built Babylon “ he constructed dykes against the irruptions of the Persian Gulf :” éxereixuos 02 noel ras Epvdpgs Sarcoons ray éxixavary. (ibid.),—a pre- caution which would seem to have been rather needless and extraordinary, unless the sea then approached much nearer to the city than it does at present. The lakes and marshes of the Euphrates would, doubtless, at that period have extended very far northward, and might well have been “ called the sea.” + I must remark that my paper in the Number of your Journal for July last, (1835,) was (as, indeed, you are well aware, ) not written for the pages of this Journal, it having been destined by me for an entirely different purpose ; and it was consequently not meant as an answer to Mr. Carter’s arguments. In consequence, however, of my subsequently requesting you to give it in- sertion “as a continuation of my former paper,” that gentleman was, I allow, entirely warranted in regarding it in the light of a further answer. This explanation will account for the want of connexion which exists be- tween that paper and my former communications,—a want of connexion which is commented upon by my opponent. { See the many instances adduced by Mr.Lyell in his Principles of Geo- logy, vol. i. ch. 13, 14. Third Series. Vol.9. No. 51. July 1836. G 42 Baron Humboldt on advancing the Knowledge by Mr. Lyell*; so that the discovery even of rock by Alex~ ander, would prove literally nothing against the fact of the increase of land in the locality in dispute. Far as it is from being my wish to dogmatize upon a sub- ject which is unquestionably attended with many difficulties ; I am even willing to admit that the gain of land to the ex- tent originally contended for by me, although far from being disproved by Mr. Carter, is also far from being proved by me. But this is not the point principally in dispute, which (inde- pendently of the grounds upon which the identity of Babel and Babylon is denied by me,) must, in the first instance at least, confine itself to the question,— Has or has not a change of such importance taken place as materially to affect the geo- graphy of the localities in question, and such, therefore, as to render the descriptions of ancient writers inapplicable to the present state of the country? Iam willing to believe that, upon further consideration, Mr. Carter himself will see reason to admit this to be the case. For myself I only wait for suffi- cient evidence, or even reasonable arguments, to relinquish any portion of my hypothesis: —which hypothesis I am wedded to in as much only as I believe it to approach the truth, and which, therefore, I shall most cheerfully abandon so far as it can be shown to be incorrect. I am, Gentlemen, yours, &c. Bremen, Feb. 3, 1836. CuHarwes T. Brxe. XI. Letter from Baron von Humboldt to His Royal Highness the Duke of Sussex, K.G., President of the Royal Society of London, on the Advancement of the Knowledge of Terrestrial Magnetism, by the Establishment of Magnetic Stations and corresponding Observations.t Sir, ue generous interest taken by Your Royal Highness in the advancement of human knowledge, encourages me to hope for the favourable reception of the request which with re- spectful confidence, I now venture to address to you. I take the liberty of soliciting your attention to the labours requisite for the investigation, by precise means, almost constantly em- ployed, of the variations of terrestrial magnetism. By obtaining the cooperation of a great number of zealous observers, pro- vided with instruments of similar construction, M. Arago, * “That a great proportion, at least, of the new deposit in the delta of the Rhone consists of rock, and not of loose incoherent matter, is perfectly ascertained. In the museum at Montpellier is a cannon taken up from the sea near the mouth of the river, imbedded in a crystalline calcareous rock.”” — Principles of Geology, vol. i. p. 234, 1st edit. + We translate this letter from Schumacher’s Astronomische Nachrichten, No. 306, which has been kindly communicated to us for the purpose. of Terrestrial Magnetism. 43 Mr. Kupffer, and myself have succeeded in the last eight years in extending these researches over a very considerable part of the northern hemisphere. Permanent magnetic stations be- ing now established from Paris to China, following towards the east the parallels from 40° to 60°, I feel myself justified insoliciting, through the intervention of Your Royal Highness, the powerful cooperation of the Royal Society of London, to sanction this enterprise, and also to promote its success by the establishment of new stations, as well in the vicinity of the magnetic equator as in the temperate part of the southern hemisphere. f An object which is equally important whether it be consi- dered in connexion with the physics of the earth or the im- provement of nautical science, has a double claim upon the attention of a Society, which has from its commencement, with constantly increasing success, cultivated the vast field of the exact sciences. Our information respecting the progressive development of the knowledge which we possess of ¢errestrzal magnetism must be indeed imperfect, if we are ignorant of the numerous valuable observations which have been made at dif- ferent epochs, and arestill being made, in the British isles, and in various parts of the equinoctial zone subject to the same empire. Our present object is to render these observa- tions more useful, that is, better adapted to manifest great physical laws, by coordinating them according to a uniform plan, and connecting them with the observations now in pro- gress upon the continent of Europe and Northern Asia. Having been much occupied during my travels in the equi- noctial regions of America, during the years 1799— 1804, with the phznomena of the intensity of the magnetic forces, and the inclination and declination of the magnetic needle, on my re- turn to my own country I conceived the design of examining the progress of the horary variations of the declination, and the perturbations to which it is liable, by employing a method which, I believe, has never yet been followed upon an exten- sive scale. In a large garden at Berlin, during the years 1806 and 1807, particularly at the period of the equinoxes and solstices, I measured the angular alterations of the mag- netic meridian, at intervals of an hour, often of half an hour, without interruption during four, five, and six days, and as many nights. Mr. Oltmanns, whose numerous calculations of geographical positions have recommended him to the notice of astronomers, kindly shared with me the fatigues of these labours. The instrument which we employed was a magnetic telescope (unette aimantée) of Prony, capable of being reversed upon its axis, suspended according to the method of Coulomb, G2 44 Baron Humboldt on advancing the Knowledge placed in a glass frame, and directed towards a very distant meridian mark, the divisions of which, illuminated during the night, indicated even six or seven seconds of horary variation. In verifying the habitual regularity of a nocturnal period, I was struck with the frequency of the perturbations, espe- cially of oscillations the amplitude of which extended beyond all the divisions of the scale, and which occurred repeatedly at the same hours before sunrise, and the violent and ac- celerated movements of which could not be attributed to any accidental mechanical cause. These vagaries of the needle, the almost periodical return of which has recently been confirmed by Mr. Kupffer in the narration of his Travels in the Caucasus, appeared to me the effect of a reaction of the interior of the earth towards the surface; I should venture to say, of magnetic storms, which indicate a rapid change of tension. From that time it has been my desire to establish on the east and west of the meridian of Berlin apparatus similar to my own, in order to obtain corresponding observations made at great di- stances and at the same hours; but the political tempest of Germany, and my hasty departure for France, whither I was sent by the Government, delayed for a length of time the ex- ecution of this project. Fortunately my illustrious friend M. Arago, after his return from the coasts of Africa and the prisons of Spain, undertook, I think about the year 1818, a series of observations upon magnetic declinations at the Ob- servatory of Paris, which, made daily at intervals uniformly fixed, and continued upon the same plan to the present day, are considered, with regard to their number and mutual con- nexion, superior to everything that has been attempted in this kind of physical investigations. Gambey’s apparatus, which is employed, is of perfect execution. Provided with micrometers and microscopes, it may be employed with more certainty and convenience than Prony’s instrument, which is attached to a strong magnetized bar of 20} inches in length. During the progress of these observations M. Arago has discovered, and proved by numerous examples, a phenomenon which differs essentially from the observation made by Prof. Hiorter at Upsal in 1741. He has discovered not only that the Aurore boreales disturb the regular progress of the horary declinations there when they are not visible, but also that early in the morning, often ten or twelve hours before the lu- minous pheenomenon is developed in a very distant place, its appearance is announced by the particular form presented by the curve of the diurnal variations, that is, by the value of the maxima of elongation of the morning and night. Another new fact was manifested in the perturbations. Mr. Kupffer having of Terrestrial Magnetism. 45 established at Cazan, nearly the eastern limit of Europe, one of Gambey’s compasses, exactly similar to that employed by M. Arago at Paris, the two observers were convinced by a certain number of corresponding measures of horary declina- tion, that, notwithstanding a difference of longitude of more than 47°, the perturbations were isochronous. They were like signals which from the interior of the earth simultaneously arrived at its surface on the jborders of the Seine and the Wolga. When in 1827 I again fixed my residence at Berlin, my first care was to renew the series of observations which I had made at short intervals during the days and nights of the years 1806 and 1807. I endeavoured at the same time to generalize the means of simultaneous observations, the acci- dental employment of which had just produced results so im- portant. One of Gambey’s compasses was placed in the mag- netic pavilion, in which no portion of iron was introduced, which had been erected in the middle of agarden. Regular observations could not commence till the autumn of 1828. Being called, in the spring of 1829, by His Majesty the Km- peror of Russia, to undertake a mineralogical tour in the North of Asia and on the Caspian Sea, I had an opportunity rapidly to extend the line of stations towards the east. At my request the Imperial Academy and the Curator of the University of Cazan erected magnetic houses at St. Petersburgh and Cazan. In a committee of the Imperial Academy, at which I had the honour of presiding, a discussion took place on the immense advantages, with regard to our knowledge of the laws of terrestrial magnetism, presented by the vast extent of country limited on one side by the curve without declina- tion of Doskino, (between Moscow and Cazan, or with more precision, according to M. Adolphe Erman, between Osabli- kowo and Doskino, in lat. 56° 0', and long. 40° 36’ east of Paris,) and on the other, by the curve without declina- tion of Arsentchewa near Lake Baikal, which is believed to be identical with that of Doskino, with a difference of meri- dians of 63° 21'. The Imperial department for Mines having generously concurred in the same object, magnetic stations have been successively established at Moscow, Barnaoul, the astronomical position of which I find to be at the foot of Altai, in lat. 53° 19! 21", long. 5" 27! 20" east of Paris, and at Nertschinsk. The Academy of St. Petersburgh has done still more, and has sent a courageous and clever astronomer, M. George Fuss, the brother of its perpetual secretary, to Pekin, and has procured the erection there of a magnetic pavilion, in the convent garden of the monks of the Creal 46 Baron Humboldt on advancing the Knowledge church. This undertaking cannot be mentioned without re- calling the fact, that, according to the Penthsaoyani, a me- dical natural history composed under the Soung dynasty, nearly four hundred years before Christopher Columbus and the natives of Europe had the least idea of magnetic declina- tion, the Chinese suspended the needle by means of a thread, to allow it perfect freedom of motion; and that they knew that when thus suspended, according to the method of Coulomb, (as in the Jesuit Lana’s apparatus in the seventeenth century, ) the needle declined to the south-east, and never rested at the true south point. Since the return of M. Fuss, M. Kowanko, a young officer of mines, whom I had the pleasure to meet in the Oural, continues the observations of horary declination, corresponding to those of Germany, St. Petersburgh, Cazan, and Nicolajeff in the Crimea, where Admiral Greigh has esta- blished one of Gambey’s compasses, the care of which is con- fided to the director of the Observatory, Mr. Knorre. I have also obtained the establishment of a magnetic apparatus at the depth of thirty-five fathoms in an adit in the mines of Freiberg in Saxony, where Mr. Reich to whom we are indebted for his valuable labours upon the mean temperature of the earth at dif- ferent depths, is assiduously engaged in making observations at regulated intervals. M. Boussingault, who neglects nothing which is calculated to advance the progress of the physics of the earth, has sent us from South America observations of horary declination made at Marmato, in the province of Antioquia, in north lat. 5° 27’, in a place where the declination is eastern, as at Cazan and Barnaoul in Asia; while on the north-western coasts of the new continent, at Sitka in the Russian settle- ments, Baron von Wrangel, also provided with one of Gam- bey’s compasses, has taken part in the simultaneous observa- tions made at the time of the solstices and equinoxes. A Spanish admiral, M. de Laborde, having been informed of a request that I had made to the Patriotic Society of the Havannah, had the kindness, unsolicited, to desire me to send him instruments proper for determining with precision the inclination, the ab- solute declination, and the horary variation of declination and intensity of the magnetic forces. ‘The valuable instruments desired, exactly similar to those in the possession of the Obser- vatoryof Paris, arrived in safety in the island of Cuba; but the alteration in the maritime command at the Havannah, and other local circumstances, have hitherto prevented the employment of them, and the establishment of a magnetic station under the tropic of Cancer. The same has also occurred up to the present time with regard to one of Gambey’s compasses which M. Arago had caused to be erected, at his own expense, to of Terrestrial Magnetism. 4:7 obtain observations in the interior of Mexico, where the soil is elevated six thousand feet above the level of the sea. Lastly, during my last residence in Paris, I had the honour of pro- posing to Admiral Duperré, Minister for marine affairs, the establishment of a magnetic station in Iceland. The pro- posal was received with the utmost eagerness, and the instru- ment, which is already ordered, will be deposited during the present summer at the port of Reikiawig, when the expedi- tion which has been sent to the north in search of M. de Blosse- ville and kis companions in misfortune returns to Iceland to continue its scientific labours. There cannot be any doubt that the Danish Government, which protects with generous ardour astronomy and the advancement of nautical science, will favour the establishment of a magnetic station in one of its provinces bordering on the polar circle. At Chili also M. Gay has made a great number of corresponding horary observations, according to the instructions of M. Arago. I have entered upon this long and minute historical detail, to show how far I have hitherto succeeded, in conjunction with my friends, in extending the number of simultaneous observa- tions. After my return from Siberia, Mr. Dove and I pub- lished, in 1830, a graphic delineation of the curves of horary declination of Berlin, Freiberg, Petersburgh, and Nicolajeff in the Crimea, to show the parallelism of these lines, notwith- standing the distance of the stations and the influence of ex- traordinary perturbations. In the comparison of the observa- tions of St. Petersburgh and Nicolajeff, use has been made of observations taken at the very small intervals of twenty mi- nutes. It must not, however, be imagined that this parallelism of inflections always exists in the horary curves. We have found that even in places very near to each other,—for instance, at Berlin and in the mines of Freiberg,—the magnetic reac- tions from the interior to the surface of the earth are not al- ways simultaneous ; that one of the needles presents consider- able perturbations, while the other preserves that regularity, which under each meridian is the function of the true time of the place. In the memoir published in 1830, I proposed the fol- lowing periods for simultaneous observations at all the stations, March 20th and 21st. ) From four o’clock in the morning of May 4th and 5th. the first day, to midnight of the se- June 21st and 22nd. cond day. The observations to be Aug. 6th and 7th. continued at each magnetic station Sept. 23rd and 24th. during the day and night, at inter- Nov. 5th and 6th. vals not exceeding one hour. Dec. 21stand 22nd. J As several observers situated upon the line of the stations 48 Baron Humboldt on advancing the Knowledge have found these periods too near to each other, it has been thought advisable to insist in preference upon the time of the solstices and equinoxes. England, from the time of William Gilbert, Graham, and Halley to that of the more recent exertions of Messrs. Gilpin, Beauloy (at Bushy), Barlow, and Christie, has produced a rich collection of materials applicable to the discovery of the physical laws which regulate the variation of the magnetic de- clination, either in one place according to the different hours and seasons, or at various distances from the magnetic equator and the lines without declination. Mr.Gilpin made observations during twelve hours every day for more than seven months. The numerous observations of Colonel Beaufoy were regularly published in Thomson’s Annals. The memorable expedi- tions to the most inhospitable regions of the North have fur- nished Messrs. Sabine, Franklin, Hood, Parry, Henry Foster, Beechey, and James Clarke Ross with a rich harvest of im- portant observations. Physical geography is indebted for a considerable increase of knowledge respecting terrestrial mag- netism and meteorology to the attempts which have recently been made to determine the form of the north-west passage or strait; and to the perilous explorations of the frozen coasts of Asia by Captains Wrangel, Lutke, and Anjou. During the progress of these noble efforts, an unexpected impulse has been given to the physical sciences by the light thrown upon them by a branch of natural philosophy the theoretical pro- gress of which for two centuries had been extremely slow. Such has been the effect of the grand discoveries of Oersted, Arago, Ampére, Seebeck, and Faraday upon the nature of electro-magnetic forces. Excited by the talents and ingenious exertions of learned travellers cooperating for the promotion of one object,’ Messrs. Hansteen, Due, and Adolphus Erman, by the fortunate union of very precise astronomical and phy- sical means, have explored, throughout the immense extent of Northern Asia, the isoclinal, isogonal, and isodynamic curves for very nearly the same epoch. When speaking of this great project, long since conceived and proposed by Mr, Hansteen, I ought, perhaps, to pass over in silence the obser- vations upon magnetic inclination which I made upon the rarely-visited frontier of Chinese Dzoungarie and on the coasts of the Caspian Sea, published in the second vo- lume of my Fragmens Asiatiques. My learned countryman Mr, Adolphus Erman, who embarked at Kamtschatka and re- turned to Europe by Cape Horn, had the rare advantage of continuing throughout a long voyage the measure of the three manifestations of terrestrial magnetism at the surface of the of Terrestrial Magnetism. 49 slobe. He employed the same instruments and the same me- thods which he had made use of from Berlin to the mouth of the Oby, and thence to the Sea of Okhotsk. That which characterizes our epoch, at a time distinguished by grand discoveries in optics, electricity, and magnetism, is the possibility of connecting pheenomena by the generalization of empirical Jaws, and the mutual aid afforded by sciences which had long remained isolated. At the present day simple observations upon horary declination or magnetic intensity, made simultaneously in situations very distant from each other, reveal, so to speak, what passes at profound depths in the interior of our planet, and in the superior regions of the at- mosphere. The luminous emanations, the polar explosions which accompany the magnetic storm, appear to follow great changes in the habitual or mean tension of terrestrial mag- netism. It would tend greatly to promote the advancement of the mathematical and physical sciences if, under the Presidency and auspices of Your Royal Highness, the Royal Society of London, to which I make it my boast to have belonged for twenty years, would exert its powerful influence to extend the line of simultaneous observations, and to establish permanent magnetic stations, either in the region of the tropics, on each side of the magnetic equator, the proximity of which neces- sarily diminishes the amplitude of the horary declinations, or in the high latitudes of the southern hemisphere and in Ca- nada. I venture to propose this latter point, because obser- vations upon horary declination made in the vast extent of the United States are still very rare. ‘Those, however, of Salem, in 1810, calculated by Mr. Bowditch, and compared by Arago with the observations of Cassini, Gilpin, and Beaufoy, merit great praise, and might serve as a guide to observers in Ca- nada in investigating whether the declination there does not diminish between the vernal equinox and the summer solstice, contrary to what occurs in Western Europe. In a memoir that I published five years ago, I suggested as magnetic sta- tions extremely favourable to the progress of our knowledge, New Holland, Ceylon, the Mauritius, the Cape of Good Hope (rendered illustrious by the labours of Sir John Her- schel), St. Helena, and some point on the eastern coast of America to the south of Quebec. In the last century, in the years 1794 and 1796, an English traveller, Mr. Macdonald, made some new and important observations upon the diurnal motion of the needle at Sumatra and St. Helena, which have since been confirmed and extended upon a large scale in the scientific expeditions of Captains Freycinet and Duperrey ; Third Series. Vol. 9. No. 51. July 1836. 50 Baron Humboldt on advancing the Knowledge the former having the command of the sloop Uranie from 1817 to 1820, and the latter, who has six times crossed the magnetic equator, commanding the sloop Coquille from 1822 to 1825. To promote the rapid advancement of the theory of terrestrial magnetism, or at least to establish with more precision empirical laws, it is necessary at the same time to prolong and to vary the lines of corresponding observations; also to distinguish in observations of horary variations, what arises from the influence of the seasons, of serene and cloudy weather and of abundant rains, of the hours of day and night, and of the true time at each place, that is, from the influence of the sun, and of all isochronous influences at the different meridians. ‘To these observations of horary declination must be united those of the annual movement of the absolute declina- tion, of the inclination of the needle, and of the intensity of the magnetic forces, the increase of which from the magnetic equator to the poles is unequal in the Western American and the Eastern Asiatic hemispheres. All these data, indispensa- ble bases for the future theory, can only acquire certainty and importance by the means of establishments which shall remain permanent for a great number of years, of Physical Obser- vatories in which the investigation of numerical elements may be repeated at settled intervals of time, and with similar in- struments. Travellers who cross a country in but one direc- tion and at one epoch merely prepare the way for an under- taking which should embrace the complete delineation of the lines without declination at intervals equally distant; the pro- gressive removal of the points of intersection of the terrestrial and magnetic equators; the changes of form in the isogonal and isodynamic lines; and the influence upon the slow or ac- celerated movement of the curves, which indubitably arises from the configuration and articulation of the continents. It must be considered fortunate if the isolated labours of tra- vellers, whose cause it is my office to plead, have contributed to give animation to a species of investigation which is the work of centuries, and which requiries the concurrence of numerous observers, distributed according to a plan arranged after mature consideration, under the direction of several of the great scientific centres of Europe. The directors should not always confine themselves to the narrow limits of the same instructions, but they should vary them freely in adapta- tion to the progressive state of physical science, and the im- provement of instruments and methods of observation. When soliciting Your Royal Highness to condescend to communicate this letter to the illustrious Society over which you preside, it is not in any degree my office to inquire, which of Terrestrial Magnetism. 51 are the magnetic stations that merit preference at the present time, or that local circumstances may admit of establishing. To have solicited the concurrence of the Royal Society of London will be sufficient to give new life to a useful enter- prise in which I have been engaged for very many years. I venture simply to express the wish that, should my proposi- tion be received with indulgence, the Royal Society would enter into direct communication with the Royal Society of Gottingen, the Royal Institute of France, and the Imperial Academy of Russia, in order to adopt measures the best adapted for the combination of what it may be proposed to establish with what already exists upon a very considerable extent of surface. Perhaps also measures might be previously concerted for the publication of partial observations, and also (if the calculation would not require too much time, and too much retard the communications, ) of the mean results. One of the happy effects of civilization and the progress of reason is, that when addressing learned societies, their willing concur- rence may be relied upon if the object for which it is solicited tends to promote the advancement of the sciences or the intel- lectual development of humanity. Labours of astonishing precision have been performed, within the last few years, with instruments of extraordinary power, in a magnetic pavilion of the Observatory of Gottin- gen, which are well worthy of the attention of philosophers, as they offer a more precise method of measuring the horary variations. The magnetized bar is of much larger dimensions than even the bar of Prony’s magnetic telescope; and the ex- tremity is furnished with a mirror, in which are reflected the divisions of a scale which is more or less distant, according to the angular value desired to be given to these divisions. By the employment of this improved method the necessity for the observer’s approaching the magnetized bar is obviated, and by preventing the currents of air produced by the proximity of the human body, or during the night, of a lamp, observa- tions may be made in the smallest intervals of time. The great geometrician Mr. Gauss,—to whom we owe this mode of making observations, as well as the means of reducing the in- tensity of the magnetic force in any part of the earth to an absolute proportion, and the ingenious invention of a magneto- meter put into motion by a multiplier of induction,—pub- lished in the Years 1834 and 1835 several series of simulta- neous observations made with similar apparatus, and at inter- vals of five or ten minutes, at Gottingen, Copenhagen, Altona, Brunswick, Leipzig, Berlin (where Mr. Encke has already established a very spacious magnetic house, near the New Royal Observatory), Milan, and Rome. Mr. Schumacher’s H2 52 Baron Humboldt on Terrestrial Magnetism. German Ephemeris (Jahrbuch fiir 1836) proves graphically, and by the parallelism of the smallest inflections of the horary curves, the simultaneity of the perturbations at Milan and Copenhagen, two cities having a difference oflatitude of 10° 13!. Mr. Gauss first made observations at the times which I pro- posed in 1830, but with the intention. of referring the angular dimensions of magnetic declination to the smallest intervals of time. (Onthe 7th of February 1834, alterations of six minutes of the arc corresponded toa single minute of time.) Mr. Gauss reduced the forty-four hours of simultaneous observations to twenty-four hours; and appointed six [seven ?] periods of the year, viz. the last Saturday of each month consisting of an uneven number of days, for the stations which are provided with his new apparatus. The small magnetized bars which he employs as magnetometers are of four pounds weight, and the large ones of twenty-five pounds. The curious apparatus of induction proper to render sensible and measurable the oscillatory movements predicted by a theory founded upon Mr. Faraday’s admirable discovery, consists of two bars fast- ened together, each of twenty-five pounds weight. I thought it proper to mention the valuable labours of Mr. Gauss, in order that those members of the Royal Society of London who have rendered most service to the study of terrestrial magnetism, and who know the localities of the colonial esta- blishments, may take into consideration whether bars of great weight, provided with a mirror, and suspended in a pavilion carefully closed, should be employed in the new stations to be established ; or whether Gambey’s compass, hitherto uniformly used in our present stations in Europe and Asia, should still be employed. In discussing this question the advantages will undoubtedly be estimated which, in the apparatus of Mr. Gauss, arise from the smaller mobility of the bars by currents of air, as well as from the facility and rapidity with which the angular divisions may be read in very short intervals of time. My desire is only to see the line of magnetic stations extended, whatever be the means by which the precision of the corre- sponding observations may be attained. I ought also to men- tion that two accomplished travellers, Messrs.Sartorius and Listing, provided with very portable instruments of small di- mensions, have very successfully employed the method of the great geometrician of Gottingen in their excursions to Na- ples and in Sicily.* Your Royal Highness will, I hope, excuse the length of this * An abstract of a memoir by Prof. Gauss in which his apparatus and me- thod of observation are fully described will be found in Lond. & Edinb. Phil. Mag., vol. il. p. 291, et seg. —Enit. Prof. Schoenbein on a peculiar Voltaic Condition of Iron. 53 communication; but I thought that it would be useful to unite under one point of view what has been done or proposed in different countries towards the attainment of extensive simul- taneous observations upon the laws of terrestrial magnetism. Accept, Sir, the acknowledgement of the profound respect with which I have the honour of being, Your Royal Highness’s, &c. &c., Berlin, April, 1836. ALEXANDER VON HuMmBo.LptT. XII. On a peculiar Voltaic Condition of Iron, by Professor ScHoENBEIN, of Bale; in a Letter to Mr. Faraday: with further Experiments on the same Subject, by Mr. Farapay, communicated in a Letter to Mr. Phillips. To Michael Faraday, Esq., D.C.L., F.R.S., &c. Sir, AS our Continental and particularly German periodicals are rather slow in publishing scientific papers, and as I am anxious to make you as soon as possible acquainted with some new electro-chemical phenomena lately observed by me, I take the liberty to state them to you by writing. Being tempted to do so only by scientific motives, I entertain the flattering hope that the contents of my letter will be received by you with kindness. The facts I am about laying before you seem to me not only to be new, but at the same time deserving the attention of chemical philosophers. Les voici. If one of the ends of an iron wire be made red hot, and at ter cooling be immersed in nitric acid, sp. gr. 1°35, neither the end in question nor any other part of the wire will be affected, whilst the acid of the said strength is well known to act rather violently upon common iron. ‘To see how far the influence of the oxidized end of the wire goes, I took an iron wire of 50 in length and 0"""5 in thickness, heated one of its ends about 3" in length, immersed it in the acid of the strength above men tioned, and afterwards put the other end into the same fluid. No action of the acid upon the iron took place. From a si- milar experiment made upon a cylindrical iron bar of 16! in length and 4!" diameter the same result was obtained. The limits of this protecting influence of oxide of iron with regard to quantities I have not yet ascertained; but as to the influ- ence of heat, I found that above the temperature of about 75° the acid acts in the common way upon iron, and in the same manner also, at common temperatures, when the said acid con- tains water beyond acertain quantity, for instance, 1, 10, 100, and even 1000 times its volume. By immersing an iron wire in nitric acid of sp. gr. 1°5 it becomes likewise indifferent to the same acid of 1°35. 54 Prof. Schoenbein on a peculiar Voltaic Condition of Iron, But by far the most curious fact observed by me is, that any number of iron wires may be made indifferent to nitric acid by the following means. An iron wire with one of its ends oxidized is made to touch another common iron wire ; both are then introduced into nitric acid of sp. gr. 1°35, so as to immerse the oxidized end of the one wire first into the fluid, and to have part of both wires above the level of the acid. Under these circumstances no chemical action upon the wires will take place, for the second wire is, of course, but a continuation of that provided with an oxidized end. But no action occurs, even after the wires have been separated from each other. If the second wire having become indif- ferent be now taken out of the acid and made to touch at any of its parts not having been immersed a third wire, and both again introduced into the acid so as to make that part of the second wire which had previously been in the fluid enter first, either of the wires will be acted upon either during their contact or after their separation. In this manner the third wire can make indifferent or passive a fourth one, and so on. Another fact, which has as yet, as far as I know, not been observed, is the following one. A wire made indifferent by any of the means before mentioned is immersed in nitric acid of sp. gr. 1°35, so as to have a considerable part of it remaining out of the fluid; another common wire is put into the same acid, likewise having one of its ends rising above the level of the fluid. The part immersed of this wire will, of course, be acted upon in a lively manner. Ifthe ends of the wires which are out of the acid be now made to touch one another, the indifferent wire will instantly be turned into an active one, whatever may be the lengths of the parts of the wires not im- mersed. (If there is any instance of chemical affinity being transmitted in the form of a current by medns of conducting bodies, I think the fact just stated may be considered as such.) It is a matter of course that direct contact between the two wires in question is not an indispensably necessary condition for communicating chemical activity from the active wire to the passive one; for any metal connecting the two ends of the wires renders the same service. Before passing to another subject, I must mention a fact, which seems to be one of some importance. An iron wire curved into a fork is made to touch at its bend, a wire pro- vided with an oxidized end; in this state of contact both are introduced into nitric acid of sp. gr. 1°35 and 30°, so as first to immerse in the acid the oxidized end; the fork will, of course, not be affected. If now a common iron wire be put into the acid, and one of the ends of the fork touched by it, this end will immediately be acted upon, whilst the other in a Letter to Mr. Faraday. 55 end remains passive; but as soon as the iron wire with the oxidized end is put out of contact with the bend of the fork, its second end is also turned active. If the parts of the fork rising above the level of the acid be touched by an iron wire, part of which is immersed and active in the acid, no commu- nication of chemical activity will take place, and both ends of the fork remain passive; but by the removal of the iron wire (with the oxidized end) from the bend of the fork this will be thrown into chemical action. As all the phenomena spoken of in the preceding lines are, no doubt, in some way or other dependent upon a peculiar electrical state of the wires, I was very curious to see in what manner iron would be acted upon by nitric acid when used as an electrode. For this purpose I made use of that form of the pile called the couronne des tasses, consisting of fifteen pairs of zinc and copper. A platina wire was connected with (what we call) the negative pole of the pile, an-iron wire with the positive one. The free end of the platina wire was first plunged into nitric acid sp. gr. 1°35, and by the free end of the iron wire the circuit closed. Under these circumstances the iron was not in the least affected by the acid; and it re- mained indifferent to the fluid not only as long as the cur- rent was passing through it, but even after it had ceased to perform the function of the positive electrode. The iron wire proved, in fact, to be possessed of all the properties of what we have called a passive one. If such a wire is made to touch the negative electrode, it instantaneously becomes an active one and a nitrate of iron is formed ; whether it be sepa- rate from the positive pole or still connected with it, and the acid be strong or weak. But another phenomenon is dependent upon the passive state of the iron, which phenomenon is in direct contradiction with all the assertions hitherto made by philosophical experi- menters. The oxygen at the anode arising from the decom- position of water contained in the acid, does not combine with the iron serving as the electrode, but is evolved at it, just in the same manner as if it were platina, and to such a volume as to bear the ratio of 1:2 to the quantity of hydrogen evolved at the cathode. To obtain this result I made use of an acid containing 20 times its volume of water; I found, however, that an acid containing 400 times its volume of water still shows the phanomenon in a very obvious manner. But I must repeat it, the indispensable condition for causing the evolution of the oxygen at the iron wire is to close the circuit exactly in the same manner as above mentioned. For if, ex- empli gratia, the circuit be closed with the negative platina wire, not one single bubble of oxygen gas makes its appear- 56 Prof. Schoenbein on a peculiar Voltaic Condition of Iron. ance at the positive iron; neither is oxygen given out at it, when the circuit is closed, by plunging first one end of the iron wire into the nitric acid, and by afterward sputting its other end in connexion with the positive pole of the pile. In both cases a nitrate of iron is formed, even in an acid con- taining 400 times its volume of water; which salt may be easily observed descending from the iron wire in the shape of brownish-yellow-coloured streaks. I have still to state the remarkable fact, that if the evolution of oxygen at the anode be ever so rapidly going on, and the iron wire made to touch the negative electrode within the acid, the disengagement of oxygen is discontinued, not only du- ring the time of contact of the wires, but after the electrodes have been separated from each other. A few moments hold- ing the iron wire out of the acid is, however, sufficient to re- communicate to it the property of letting oxygen gas evolve at its surface. By the same method the wire acquires its evolv- ing power again, whatever may have been the cause of its loss. ‘The evolution of oxygen also takes place in dilute sul- phuric and phosphoric acids, provided, however, the circuit be closed in the manner above described. It is worthy of remark, that the disengagement of oxygen at the iron in the last-named acids is much easier stopt, and much more difficult to be caused again, than is the case in nitric acid. In an aqueous solution of caustic potash, oxygen is evolved at the positive iron, in whatever manner the circuit may be closed, but no such disengagement takes place in aqueous solutions of hydracids, chlorides, bromides, iodides, fluorides. The oxy- gen, resulting in these cases from the decomposition of water, and the anion (chlorine, bromine, &c.) of the other electrolyte decomposed combine at the same time with the iron. To generalize these facts, it may be said, that independently of the manner of closing the circuit, oxygen is always dis- engaged at the positive iron, provided the aqueous fluid in which it is immersed do not (in a sensible manner) chemically act upon it; and that no evolution of oxygen at the anode in contact with iron under any circumstances takes place, if besides oxygen another anion is set free possessed of a strong affinity for iron. This metal having once had oxygen evolved at itself, proves always to be indifferent to nitric acid of a cer- tain strength, whatever may be the chemical nature of the fluid in which the phenomenon has taken place. IT have made a series of experiments upon silver, copper, tin, lead, cadmium, bismuth, zinc, mercury, but none showed any resemblance to iron, for all of them were oxidized when serving as positive electrodes. Having at this present mo- ment neither cobalt nor nickel at my command, I could not Mr. Faraday on a peculiar Voltaic Condition of Iron. 57 try these magnetic metals, which I strongly suspect to act in the same manner as iron does. It appears from what I have just stated that the anomalous bearing of the iron has nothing to do with its degree of affi- nity for oxygen, but must be founded upon something else. Your sagacity, which has already penetrated into so many mysteries of nature, will easily put away the veil which as yet covers the phznomenon stated in my letter, in case you should think it worth while to make it the object of your re- searches. Before I finish I must beg of you the favour of overlooking with indulgence the many faults I have, no doubt, committed in my letter. Formerly I was tolerably well acquainted with your native tongue; but now, having been out of practice in writing or speaking it, it is rather hard work to me to express myself in English. It is hardly necessary to say that you may privately or publicly make any use of the contents of this letter. I am, Sir, your most obedient Servant, C. T. ScHOENBEIN, Bale, May 17, 1836. Prof. of Chem. in the University of Bale. Dear PHIL.irs, The preceding letter from Professor Schoenbein, which I received a week or two ago, contains facts of such interest in relation to the first principles of chemical electricity, that I think you will be glad to publish it in your Philosophical Ma- gazine. I send it to you unaltered, except in a word or two here and there; but am encouraged by what I consider the Professor’s permission (or rather the request with which he has honoured me,) to add a few results in confirmation of the effects described, and illustrative of some conclusions that may be drawn from the facts. The influence of the oxidized iron wire, the transference of the inactive state from wire to wire, and the destruction of that state, are the facts I have principally verified ; but they are so well described by Professor Schoenbein that I will not add a word to what he has said on these points, but go at once to other results. Iron wire, as M. Schoenbein has stated, when put alone in- to strong nitric acid, either wholly or partly immersed, ac- quires the peculiar inactive state. This I find takes place best in a long narrow close vessel, such as a tube, rather than in a flat broad open one like a dish. When thus rendered qui- 58 Mr. Faraday on a peculiar Voltaic Condition of Iron. escent by itself, it has the same properties and relations as that to which the power has been communicated from other wires. If a piece of ordinary iron wire be plunged wholly or in part into nitric acid of about specific gravity 1°3 or 1°35, and after action has commenced it be touched by a piece of platina wire, also dipping into the acid, the action between the acid and the iron wire is instantly stopped. The immersed portion of the iron becomes quite bright, and remazns so, and is in fact in the same state, and can be used in the same manner as the iron rendered inactive by the means already described. This pro- tecting power of platina with respect to iron is very constant and distinct, and is the more striking as being an effect the very reverse of that which might have been anticipated prior to the knowledge of M. Schoenbein’s results. It is equally exerted if the communication between it and the iron is not immediate, but made by other metals; as, for instance, the wire of a galvanometer ; and if circumstances be favourable, a small surface of platina will reduce and nullify the action of the acid upon a large surface of iron. This effect is the more striking if it be contrasted with that produced by zinc; for the latter metal, instead of protecting the iron, throws it into violent action with the nitric acid, and determines its quick and complete solution. The phenomena are well observed by putting the iron wire into nitric acid of the given strength, and touching it in the acid alternately by pieces of platina and zinc: it becomes active or inactive ac- cordingly; being preserved by association with the platina, and corroded by association with the zinc. So also, as M. Schoenbein has stated, if iron be made the negative electrode of a battery containing from two to ten or more pairs of plates in such acid, it is violently acted upon; but when rendered the positive electrode, although oxidized and dissolved, the process, comparatively, is extremely slow. Gold has the same power over iron immersed in the nitric acid that platina has. Even silver has a similar action; but from its relation to the acid, the effect is attended with pecu- liar and changeable results, which I will refer to hereafter. A piece of box-wood charcoal, and also charcoal from other sources, has this power of preserving iron, and bringing it into the inactive state. Plumbago, as might be expected, has the same power. When apiece of bright steel was first connected with a piece of platina, then the platina dipped into the acid, and lastly the steel immersed, according to the order directed in the former cases by Professor Schoenbein, the steel was preserved by the platina, and remained clear and bright in the acid, even after Mr. Faraday on a peculiar Voltaic Condition of Iron. 59 the platina was separated from it, having, in fact, the proper- ties of the inactive iron. When immersed of itself, there was at first action of the usual kind, which, being followed by the appearance of the black carbonaceous crust, known so well in the common process of examining steel, the action immediately ceased, and the steel was preserved, not only at the part im- mersed, but upon introducing a further portion, it also remained clean and bright, being actually protected by association with the carbon evolved on the part first immersed. When the iron is in this peculiar inactive state, as M. Schoen- bein has stated, there is not the least action between it and the nitric acid. I have retained such iron in nitric acid, both alone and in association with platina wire for 30 days, without change; the metal has remained perfectly bright, and not a particle has been dissolved. A piece of iron wire in connexion with platina wire was entirely immersed in nitric acid of the given strength, and the latter gradually heated. No change took place until the acid was nearly at the boiling-point, when it and the iron suddenly entered into action, and the latter was instantly dissolved. As an illustration of the extent and influence of this state, I may mention, that with a little management it can be shown that the iron has lost, when in the peculiar state, even its power of precipitating copper and other metals. A mixture of about equal parts of a solution of nitrate of copper and nitric acid was made. Iron in the ordinary, or even in the peculiar state, when put into this solution, acted, and copper was precipitated ; but if the inactive iron was first connected with a piece of pla- tina dipping into the solution, and then its own prepared sur- face immersed, after a few seconds the platina might be re- moved, and the iron would remain pure and bright for some time. At last it usually started into activity, and began to pre- cipitate copper, being itself rapidly corroded. When silver is the metal in solution, the effect is still more striking, and will be referred to immediately. I then used a galvanometer as the means of connexion be- tween the iron and other metals thus associated together in nitric acid, for the purpose of ascertaining, by the electric cur- rents produced, in what relative condition the metals stood to each other; and I will,in the few results I may have to describe, use the relations of platina and zinc to each other as the terms under of comparison by which to indicate the states of these metals various circumstances. The oxidized iron wire of Professor Schoenbein is, when in association with platina, exactly as another piece of platina would be. There is no chemical action, nor any electric cur- 60 Mr. Faraday on a peculiar Voltaic Condition of Iron. rent. The iron wire rendered inactive either by association with the oxidized wire or in any other way, is also as platina to the platina, and produces no current. When ordinary iron and platina in connexion by means of the galvanometer are dipped into the acid, (it matters not which first,) there is action at the first moment on the iron, and a very strong electric current, the iron being as zinc to the pla- tina. The action on the iron is, however, soon stopped by the influence of the platina, and then the current instantly ceases, the iron now acting as platina to the platina. If the iron be lifted into the air for a moment until action recom- mences on it, and be then reimmersed, it again produces a current, acting as zinc to the platina; but as before, the mo- ment the action stops, the current is stopt also. If an active or ordinary, and an inactive or peculiar iron wire be both immersed in the nitric acid separately, and then connected either directly or through the galvanometer, the se- cond does not render the first inactive, but is itself thrown into action by it. At the first moment of contact, however, a strong electric current is formed, the first iron acting as zinc, and the second as platina. Immediately that the chemical action is reestablished at the second as well as the first, all current ceases, and both pieces act like zinc. On touching either of them in the acid with a piece of platina, both are protected, and cease to act; but there is no current through the galva- nometer, for both change together. When iron was associated with gold or charcoal, the phe- nomena were the same. Using steel instead of iron, like ef- fects ensued. One of the most valuable results in the'present state of this branch of science which these experiments afford, is the addi- tional proof that voltaic electricity is due to chemical action, and not to contact. The proof is equally striking and decisive with that which I was able to give in the Eighth Series of my Ex- perimental Researches (par. 880)*. What indeed can show more evidently that the current of electricity is due to chemi- cal action rather than to contact, than the fact, that though the contact is continued, yet when the chemical action ceases, the current ceases also ? It might at first be supposed, that in consequence of the peculiar state of the iron, there was some obstacle, not merely to the formation of a current, but to the passage of one; and that, therefore, the current which metallic contact tended to produce could not circulate in the system. This supposition was, however, negatived by removing the platina wire into a * See Lond. and Edinb. Phil. Mag,, vol. vi. p. 36.—Enir. Mr. Faraday on a peculiar Voltaic Condition of Iron. 61 second cup of nitric acid, and then connecting the two cups by a compound platina and iron wire, putting the platina into the first vessel, and the iron attached to it into the second. The second wire acted at the first moment, producing its correspond- ing current, which passed through the first cup, and conse- quently through the first and inactive wire, and affected the galvanometer in the usual way. As soon as the second iron was brought into the peculiar condition, the current of course ceased; but that very cessation showed that the electric cur- rent was not stopped by a want of conducting power, or a want of metallic contact, for both remained unchanged, but by the absence of chemical action. These experiments, in which the current ceases whilst contact is continued, combined with those I formerly gave, in which the current is produced though contact does not exist, form together a perfect body of evidence in respect to this elementary principle of voltaic action. With respect to the state of the iron when inactive in the nitric acid, it must not be confounded with the inactive state of amalgamated or pure zinc in dilute sulphuric acid. The distinction is easily made by the contact of platina with either in the respective acids, for with the iron such association does nothing, whereas with the zinc it develops the full force of that metal and generates a powerful electric current. The iron is in fact as if it had no attraction for oxygen, and there- fore could not act on the electrolyte present, and consequently could produce no current. My strong impression is that the surface of the iron is oxidized, or that the superficial particles of the metal are in such relation to the oxygen of the electrolyte as to be equivalent to an oxidation ; and that having thus their affinity for oxygen satisfied, and not being dissolved by the acid under the circumstances, there isno renewal of the metallic sur- face no reiteration of the attraction of successive particles of the iron on the elements of successive portions of the electrolyte, and therefore not those successive chemical actions by which the electric current (which is definite in its production as well as in its action) can be continued. In support of this view I may observe, that in the first ex- periment described by Professor Schoenbein, it cannot be doubted that the formation of a coat of oxide over the iron when heated is the cause of its peculiar and inactive state: the coat of oxide is visible by its colour. In the next place all the forms of experiment by which this iron, or platina, or charcoal, or other voltaic arrangements are used to bring or- dinary iron into the peculiar state, are accompanied by a de- termination of oxygen to the surface of the iron; this is shown 62 Mr. Faraday on a peculiar Voltaic Condition of Iron. by the electric current produced at the first moment, and which in such cases always precedes the change of the iron from the common io the peculiar state. ‘That the coat of oxide produced by common means might be so thin as not to be sensible and yet be effectual, was shown by heating a piece of iron an inch or two from the end, so that though blue at the heated part, the end did not seem in the slightest degree affected, and yet that end was in the peculiar state. Again, whether the iron be oxidized in the flame much or only to the very slight degree just described, or be brought into the pe- culiar state by voltaic association with other pieces or with platina, &c., still if a part of its surface were removed even in the smallest degree and then the new surface put into contact with the nitric acid, that part was at the first moment as com- mon iron; the state being abundantly evident by the electrical current produced at the instant of immersion. Why the superficial film of oxide which I suppose to be formed when the iron is brought into the peculiar state by voltaic association, or occasionally by immersion alone into nitric acid, is not dissolved by the acid, is I presume dependent upon the peculiarities of this oxide and of nitric acid of the strength required for these experiments; but as a matter of fact it is well known that the oxide produced upon the surface of iron by heat, and showing itself by thin films of various colours, is scarcely touched by nitric acid of the given strength though left in contact with it for days together. That this does not depend upon the film having any great thickness, but upon its peculiar condition, is rendered probable from the fact that iron oxidized by heat, only in that slight degree as to offer no difference to the eye, has been left in nitric acid of the given strength for weeks together without any change. And that this mode of superficial oxidation, or this kind of oxide, may occur in the voltaic cases, is rendered probable by the results of the oxidation of iron in nitrate of silver. When nitrate of silver is fused and common iron dipped into it, so as to be thoroughly wetted, being either alone or in associa- tion with platina, the iron does not commence a violent action on the nitrate and throw down silver, but it is gradually oxi- dized on the surface with exactly the same appearances of colour, uniformity of surface, &c., as if it were slowly oxi- dized by heat in the air. Professor Schoenbein has stated the case of iron when acting as the positive electrode of a cowronne des tasses. If that in- strument be in strong action, or if an ordinary battery be used containing from two to ten or more plates, the positive iron in- stantly becomes covered in the nitric acid with a coat of oxide, Mr. Faraday on a peculiar Voltaic Condition of Iron. 63 which though it does not adhere closely still is not readily dis- solved by the acid when the connexion with the battery is broken, but remains for many hours on the iron, which itself is in the peculiar inactive state. If the power of the voltaic apparatus. be very weak, the coat of oxide on the iron in the nitric acid often assumes a blue tint like that of the oxide formed by heat. A part of the iron is however always dis- solved in these cases. If it be allowed that the surface particles of the iron are associated with oxygen, are in fact oxidized, then all the other actions of it in combination with common iron and other metals will be consistent; and the cause of its platina-like action, of its forming a strong voltaic current with common iron in the first instance, and then being thrown into action by it, will be explained by considering it as having the power of determining and disposing of a certain portion of hydrogen from the electrolyte at the first moment and being at the same time brought into a free metallic condition on the surface so as to act afterwards as ordinary iron. I need scarcely refer here to the probable existence of a very close connexion between the phzenomena which Professor Schoenbein has thus pointed out with regard to iron, and those which have been observed by others, as Ritter and Marianini, with regard to secondary piles, and A. De la Rive with respect to peculiar affections of platina surfaces. In my Experimental Researches (par. 4.76.) I have recorded a case of voltaic excitement, which very much surprised me at the time, but which I can now explain. I refer to the fact stated, that when platina and iron wire were connected vol- taically in association with fused nitrate or chloride of silver, there was an electric current produced, but in the reverse di- rection to that expected. On repeating the experiment I found that when iron was associated with platina or silver in fused nitrate or chloride of silver, there was occasionally no current, and when a current did occur it was almost con- stantly as if the iron was as platina, the silver or platina used being as zinc. In all such cases, however, it was a thermo-electric current which existed. The volta-electric current could not be obtained, or lasted only for a moment. When iron in the peculiar inactive state was associated with silver in nitric acid sp. gr. 1°35, there was an electric cur- rent, the iron acting as platina; the silver gradually became tarnished and the current continued for some time. When ordinary iron and silver were used in the nitric acid there was immediate action and a current, the iron being as zinc, to the silver as platina. In a few moments the current was reversed, 64 Mr. Faraday on a peculiar Voltaic Condition of Iron. and the relation of the metals was also reversed, the iron being as platina, to the silver as zinc; then another inversion took place, and then another, and thus the changes went on some- times eight or nine times together, ending at last generally in a current constant in its direction, the iron being as zinc, to the silver as platina: occasionally the reverse was the case, the predominant current being as if the silver acted as zine. This relation of iron to silver, which was before referred to page 58, produces some curious results as to the precipitation of one metal by another. If a piece of clean iron is put into an aqueous solution of nitrate of silver, there is no immediate apparent change of any kind. After several days the iron will become slightly discoloured, and small irregular crystals of sil- ver will appear; but the action is so slow as to require time and care for its observation. When a solution of nitrate of silver to which a little nitric acid had been added was used, there was still no sensible immediate action on the iron. When the solution was rendered very acid, then there was direct imme- diate action on the iron; it became covered with a coat of pre- cipitated silver: the action then suddenly ceased, the silver was immediately redissolved, and the iron left perfectly clear, in the peculiar condition, and unable to cause any further preci- pitation of the silver from the solution. It is a remarkable thing in this experiment to see the silver rapidly dissolve away in a solution which cannot touch the iron, and to see the iron in a clean metallic state unable to precipitate the silver. Iron and platina in an aqueous solution of nitrate of silver produce no electric current; both act as platina. When the solution is rendered a little acid by nitric acid, there is a very feeble current for a moment, the iron being as zinc. When still more acid is added so as to cause the iron to precipitate silver, there is a strong current whilst that action lasts, but when it ceases the current ceases, and then it is that the silver is redissolved. The association of the platina with the iron evidently helps much to stop the action. When iron is associated with mercury, copper, lead, tin, zinc, and some other metals, in an aqueous solution of nitrate of silver, it produces a constant electric current, but always acts the part of platinum. ‘This is perhaps most striking with mercury and copper, because of the marked contrast it affords to the effects produced in dilute sulphuric acid and most or- dinary solutions. The constancy of the current even causes crystals of silver to form on the iron as the negative electrode. It might at first seem surprising that the power which tends to reduce silver on the iron negative electrode did not also bring back the iron from its peculiar state, whether that be a M. Berthier on the Magnetic Action of Manganese. 65 state of oxidation or not. But it must be remembered that the moment a particle of silver is reduced on the iron, it not only tends to keep the iron in the peculiar state according to the facts before described, but also acts as the negative elec- trode, and there is no doubt that the current of electricity which continues to circulate through the solution passes es- sentially between it and the silver, and not between it and the iron, the latter metal being merely the conductor interposed between the silver and the copper extremities of the metallic arrangement. I am afraid you will think I have pursued this matter to a greater length than it deserves; but I have been exceedingly interested by M. Schoenbein’s researches, and cannot help thinking that the peculiar condition of iron which he has pointed out will (whatever it may depend upon) enable us hereafter more closely to examine the surface-action of the metals and electrolytes when they are associated in voltaic combinations, and so give us a just knowledge of the nature of the two modes of action by which particles under the in- fluence of the same power can produce either local effects of combination or current affinity *. I am, my dear Phillips, very truly yours, Royal Institution, June 16, 1836. M. Farapay. XIII. Notice of the Magnetic Action of Manganese at Low Temperatures, asstated by M. Berthier. In a letter from Mr. Faraday. To the Editors of the Philosophical Magazine and Journal. GENTLEMEN, (THE following fact, stated by M. Berthier, has great interest to me, in consequence of the views I have taken of the general magnetic relations and characters of the metals. As you have done me the favour to publish these views in your Magazine}, perhaps you will think the present note also worth a place in the next Number. Berthier in his Traité des Essais par la Voie Séche, tome i. p- 532, has the following passage in his account of the physical properties of the metals. ‘‘ Magnetism.—There are only three metals which are habitually endowed with magnetic force: these are iron, cobalt, and nickel; but manganese also possesses it beneath a certain degree of temperature much below zero.” ‘There is no reference to any account of this experi- * Experimental Researches, Eighth Series, parr. 947. 996. [or Lond. and Edinb. Phil. Mag., vol. vi. pp. 174, 337.—Enzr. ] + See Lond. and Edinb. Phil. Mag., vol. viii. p. 177.—Enir. Third Series. Vol. 9. No. 51, July 1836. 66 Zoological Society. mental result, and it is therefore probable that M. Berthier himself has observed the fact, in which case it cannot be doubted; but the result is so important that any one possess- ing pure manganese who can verify the result and give an ac- count of the degree of temperature at which the change takes place, will be doing a service to science. The great point will be to secure the perfect absence of iron or nickel from the man-=s ganese. With respect to cobalt, I have already stated that when pure, I cannot find it to possess magnetic properties at common or low temperatures. I am, Gentlemen, yours, &c., Royal Institution, June 17, 1836. M. Farapay. XIV. Proceedings of Learned Societies. ZOOLOGICAL SOCIETY. [Continued from vol. viii. page 348.] Dec. 8, te, (eta aac were exhibited of various Birds chiefly from 1835. ™ the Society’s collection, which Mr. Gould regarded as hitherto undescribed. At the request of the Chairman he pointed out the distinguishing peculiarities of the undermentioned species : viz. Phenicura plumbea, Pyrgita cinnamomea, Merula castanea, Sauro- phagus Swainsonii, Brachypus gularis, Merula Nestor, Ianthocincla pectoralis, and Lanth, albogularis ; and also the following new genus. STENORHYNCHUS. Rostrum capite longius, gracile, compressum, subfornicatum ; mandibula superiore leviter emarginata, culmine in frontem de- pressissimum producto. Nares ovales, aperte. - Ale breviuscule, subrotundate ; remige 1ma brevissima, 4ta lon- giore; 5t4 et 6ta 4tam subzequantibus, Cauda mediocris, rotundata ; rectricibus decem ? Pedes xobusti: acrotarsis subscutellatis; halluce ungueque pos- tico fortibus, tarsum longitudine subzquantibus, digito inter- medio brevioribus. Plume molles. Srenoruyncuus ruFicaupa. Sten. supra sordide saturate brun- neus, rufo caudam versus tinctus; caudd, secundariis, scapulari- busque saturate rufo-brunneis ; subtis brunnescenti-cinereus, in rufo-brunneum ad latera vergens. Long. tot. 94 poll.; rostri, 14; ale, 4%; caude@, 34; tarsi, 1. Rostrum nigrum ; pedes brunnei. Hab. As only-one specimen of this bird has yet been seen, itis doubt- ful whether it may not possess twelve tail-feathers; but, after a care- ful examination, Mr. Gould can discover no more than ten. A paper was read, entitled ‘‘ Mémoire sur une Nouvelle Espéce Zoological Society. 67 de Poisson du Genre Histiophore, de la Mer Rouge: par M. E. Riip- pell, M.D., Memb. Ext. Z.S.” It was accompanied by a drawing of the fish described im it. MM. Cuvier and Valenciennes have described, in their ‘ Histoire Naturelle des Poissons,’ three species of Sword-fishes of the genus Histiophorus ; from all of which Dr. Riippell regards his fish as di- stinct, although it apparently approaches most nearly to Hist. Ame- ricanus : it should seem that its occurrence at Djetta, on the coast of Arabia, was only accidental, as the Arab fishermen knew no name for it. The most striking peculiarity of the new species is the uni- formity of the colour of its dorsal fin: in all those which were pre- viously known the first dorsal fin is varied with spots; in the one obtained by Dr. Riippell, the first dorsal fin is black throughout and destitute of spots, on which account its discoverer proposes for it the name of Histiophorus immaculatus, under which its characters are given in the Society’s ‘‘ Proceedings.” Dr. Riippell describes the fish in considerable detail. He has not, however, examined it anatomically, on account of his possessing only one specimen, which he had deposited in the Frankfort Mu- seum. The following notes by Sir Robert Heron, Bart., were read. “In many books that I have seen some errors are made in the history of the Kangaroos, which my long possession of those animals enables me to correct. “The great Kangaroo does not make use of his tail in leaping. He uses it in walking, and still more in standing. When excited, he stands (the male only) on tip-toe and on his tail; and is then of prodigious height. In fighting he does not stand on the tail and one leg, but balances himself for a moment on the tail only, and strikes forward with both hind legs. “The bush Kangaroo, or Kanguru enfumé of Cuvier, never uses his legs in fighting. He generally contents himself with threatening with his teeth and alow growl; but I have seen him, when attacked by an Lmu, jump up at the bird’s head. Neither of them, however, has persevered in annoyance. «When sitting in a state of repose the great Kangaroo throws the tail behind him: the lesser one before him, between his legs.” The following note by Sir Robert Heron, Bart., was also read, as giving an account of an extraordinary instance of want of sagacity in a Dog. “A large old white female terrier followed me this autumn from Grantham. She remained perfectly satisfied for three weeks, when, on myagain going to attend the petty sessions, she again followed me, I then found that she belonged to one of my colleagues, the Rev. Mr. Ottley ; and that she had long been a great favourite in the family, who were greatly distressed at her loss. It happened that Mr. Ottley and I each rode a chestnut pony with a long tail. This had com- pletely deceived the dog, whose unsentimental friendship did not prompt her to ask any further bree 2 68 Soological Society. Dec. 22.—Specimens were‘ exhibited of several Rodent animals collected during his survey of the Straits of Magalhaens, by Capt. P. P. King, R.N., Corr. Memb. Z. S., and presented by him to the Society. They were accompanied by some notes by Capt. King, which were read. In bringing the animals severally under the notice of the Meeting, Mr. Bennett first directed particular attention to one of them, which constituted, in his estimation, a new species in the genus Ctenomys, Blainv. To elucidate its relations with the nearly allied genera of Herbivorous Rodentia, Octodon, Benn., and Poephagomys, F. Cuv., a specimen of Octodon Cumingii was exhibited and compared with it; and Mr. Bennett stated his intention of entering with some detail into the subject in a paper which he proposed to prepare upon it. In the structure of its molar teeth, Octodon may be regarded as occupying an intermediate station between Poephagomys and Cteno- mys. In Octodon the molars of the upper jaw differ ‘remarkably in form from those of the lower. The upper molars have on their inner side a slight fold of enamel, indicating a groove tending in some measure to separate on this aspect the mass of the tooth into two cylinders: on their outer side a similar fold penetrates more deeply, and behind it the crown of the tooth does not project outwardly to so great an extent as it does in front. Ifeach molar tooth of the upper jaw be regarded as composed of two partially united cylinders, slightly compressed from before backwards, and somewhat oblique in their direction, the anterior of these cylinders might be described as entire, and the posterior as being truncated by the removal of its outer half. Of such teeth there are, in the upper jaw of Octodon, on each side, four; the hindermost being the smallest, and that in which the peculiar form is least strongly marked. In Ctenomys, all the molar teeth, both of the upper and the lower jaw, correspond with the structure that exists in the upper jaw of Octodon, excepting that their crowns are slenderer and more obliquely placed, whence the external emargination becomes less sharply defined; and also excepting that the hinder molar in each jaw is so small as to be almost evanescent: as is generally the case, however, the relative position of the teeth is counterchanged, and the deficiency in the outline of the crown of the tooth, which in the upper jaw is external, is, in the lower jaw, internal. In the lower jaw of Octodon the crowns of the molars assume a figure very different from those of the upper, dependent chiefly on the prolongation of the hinder portion of the tooth to the same lateral extent as its anterior part: each of them consists of two cylinders, not disjoined in the middle where the bony portion of the crown is continuous, but partially separated by a fold of enamel on either side producing a corresponding notch; placed obliquely with respect to the jaw they resemble, in some measure, a figure of 8 with its elements flattened obliquely, pressed towards each other, and not connected by the transverse middle bars. With the lower molars of Octodon those of Poephagomys, as figured by M. F. Cuvier, correspond in structure in both jaws. Octodon thus exhibits, Loological Society. 69 in its dissimilar molars, the types of two genera: the molars of its upper jaw represent those of both jaws of Ctenomys; those of its lower jaw correspond with the molars of both jaws of Poephagomys. The characters distinguishing the new species of Ctenomys are chiefly those of colour. The Cten. Brasiliensis is described by M. de Blainville as being shining rufous above, and reddish white below. The new species may be characterized as the Ctenomys Magellanicus. Captain King states that this “little animal is very timid; feeds upon grass; and is eaten by the Patagonian Indians. It inhabits holes, which it burrows, in the ground: and, from the number of the holes, it would appear to be very abundant.” A second animal exhibited appears, like the preceding, to represent in the more southern latitudes of South America a genus whose type was originally observed in Brasil. Mr. Bennett regarded it as a second species of Kerodon, F. Cuv., chiefly distinguishable from the one discovered by Prince Maximilian of Wied by its more uniform colour. Excepting a slight dash of white behind the ear, and a longer line of the same colour marking the edge of each branch of the lower jaw, the animal is entirely grey; the upper surface being distinguished from the under by a greater depth of tint, and by the in- termixture of a free grizzling of yellow and black. The crowns of the molar teeth, as in the typical species, consist of bone surrounded by two triangles of enamel, the bases of which are connected together by a short line of enamel passing from the one to the other: all the lines being slender and sharply defined. For this species Mr. Bennett proposed the name of Kerodon Kingii. The third animal exhibited was remarked on as constituting a new species of Cavy, distinct from all those that were previously known, including the two which have recently been described by M. Brandt in the ‘ Nouveaux Mémoires de 1 Académie Impériale de St. Peters- bourg.’ Mr. Bennett characterized it as the Cavia Cutleri, King MSS. The general form of the animal is probably similar to that of the restless Cavy, Cavia Cobaya, Gmel., popularly known as the Guinea- pig. It is covered universally by long, smooth, glossy, black hairs, which are slightly tinged with brown. Its ears are rather large, broadly expanded, and hairy ; and between them the hairs are longer than those on the adjoining parts, occasioning a slight appearance of a crest. On the middle of each cheek the hairs radiate as from a centre, almost in a similar manner to that in which they spread from around the crown of the bonneted Monkeys, and the skin is conse- quently left in the middle point almost bare. The dentition is alto- gether that of the restless Cavy, and the incisors, as in it, are white. The skull is rather more expanded laterally, which gives to it an appearance of comparative flatness. «This animal was known, on the survey, by the name of the Pe- ruvian Cavy. The specimen in the Society’s collection was presented to one of the officers of the Beagle by an American sailing-master, 70 Zoological Society. of Stonington, U.S., a very intelligent person, to whom we were much indebted. The trivial name which I have proposed for it is in recollection of the benefit we derived from his experience and. know- ledge of the intricate navigation of the south-western coast of Pata- gonia, which was freely imparted to us on several occasions.””— Pub. kK: The collection also contained specimens of a Mouse, for which Mr. Bennett proposed the name of Mus Magellanicus. Specimens were exhibited of several Marsupialia, on which Mr. Ogilby made the following remarks. «A small collection of Marsupial Quadrupeds, which Mr, Gould lately received from his brother-in-law, Mr, Coxen, contains two or three interesting species, which the usual kindness of Mr. Gould enables me to notice. They were all procured, as I am informed, in the country beyond the Hunter River, about eighty miles north of Sydney in New South Wales. The most remarkable is an unde- scribed species of Phalanger, which I propose to call Phalangista Canina. It is similar in size and general proportions to Phal. Vulpina, and the two allied species described in the ‘ Pro- ceedings’ for 1830-31, page 135, (Phil. Mag. and Annals, N.S., vol. xi. p. 133.) but is easily distinguished ‘from them all by the small size and round form of the ears, as well as by the distribution of the colours. All the upper parts of the body, the head, cheeks, back, sides, and outer face of the arms and thighs are of a uniform grizzled brown; the throat, breast, belly, and interior of the members dirty ashy grey with a slight shade of yellow. The ears are only an inch in length and about the same in breadth, being thus little more than half as long as in Phal. Vulpina. They are naked within, but co- vered with deep coffee-coloured fur on the outside; the nose, and the paws, both before and behind, are dark brown; and the tail is bushy and entirely black to within about 2 inches of its root, which is of the same colour as the back. All these circumstances distin- guish the present species from Phal. Vulpina, with which alone it can possibly be confounded, and in which the backs of the ears, and the cheeks and paws are yellowish white, whilst the black colour oc- cupies only the latter half of the tail. Both these animals have long black vibrisse, and a tuft of similar stiff hair on the cheek, about an inch below and behind the eye. The whole length from the nose to the root of the tail is 2 feet; the length of the tail 133 inches, Phal. Cookii. 1 notice this species merely to observe that the present specimen is the only certain evidence we possess of this animal being an inhabitant of Continental Australia. Cook observed it in Van Diemen’s Land, and I had never been able to ascertain the precise locality from which the various other individuals I had for- merly examined, were obtained. Macropus Eugenii. This specimen agrees with M. Desmarest’s de- scription, and is interesting as coming from a very distant part of the country. Perameles obesula. An adult specimen of the same size as the Cambridge Philosophical Society. 71 full-grown Per. nasuta. I notice it to mention that the teeth are, in all respects, similar to those of Per. nasuta, both in form and number. The collection contains besides, two very fine specimens of Pe- taurus Taguanoides; one of Pet. Sciureus; one of Hydromys chryso- gaster ; and a young Koala.” —W. O. PROCEEDINGS AT THE FRIDAY EVENING MEETINGS OF THE ‘ MEMBERS OF THE KOYAL INSTITUTION. March 25.—Mr. Goadby on Insect Anatomy. April 15.—Sir James South on Astronomical Observations as car- ried on in the fixed Observatory. April 22.—Sir James South. ‘The same (concluded). April 29.—Mr. Faraday on Plumbago and Pencils. May 6.—Mr. Daniell on a new and constant Voltaic Battery. May 13.—Dr. Lardner on Steam communication with India (con- cluded). May 20.—Professor Mayo on some of the uses of Sensation. May 27.—Mr. Pettigrew unrolled an Egyptian Mummy. June 3.—Mr. Beamish on the present state and prospects of the Thames Tunnel. June 10.—Mr. Faraday. Considerations respecting the nature of Chemical Elements. CAMBRIDGE PHILOSOPHICAL SOCIETY, [Continued from vol. viii. p. 431.] A meeting of the Philosophical Society was held on Monday evening, April 18th, Dr. Clark, the President, in the chair. The Astronomer Royal (lately Prof. Airy) read a communication on the intensity of light in the neighbourhood of a caustic. One object of this investigation was to determine what must be the circum- stances of the rainbow on the undulatory theory of light. After- wards Mr. Hopkins gave an account of the agreement between the results of his theory of elevatory geological forces, and the phe- nomena of faults, as observed by him in the strata of Derbyshire. A meeting of this Society was held on Monday evening, May 2nd, Dr. Thackeray, Vice-President, in the chair. A memoir was read by S. Earnshaw, Esq., St. John’s, “ On the Integration of the Equa- tion of Continuity of Fluids in Motion ;” also a memoir by Professor Miller on the Measurements of the Axes of Optical Elasticity of certain Crystals. This memoir contained various determinations, from which it appears that the law concerning the connexion of the crystalline and the optical properties of crystals suggested by Pro- fessor Neumann, namely, that the optical axes are the axes of cry- stalline simplicity, is false; but that it is true, in many of the cases hitherto examined, that one of the optical axes coincides with the axis of a principal crystalline zone. Afterwards Mr.Webster, of Tri- nity College, made some observations on the periodical and occa- 72 | Intelligence and Miscellaneous Articles. sional changes of the height of the barometer, and on their con- nexion with the changes of temperature arising from the seasons and from the condensation of aqueous vapour. A meeting of this Society was "also held on Monday evening, May 16th, Dr. Thackeray, V.P., in the chair. A letter from A. De Morgan, Esq., to the Rev. George Peacock, was read, containing a sketch of a method of introducing discontinuous constants into the arithmetical expressions for infinite series. Also a memoir by P. Kelland, Esq., of Queen’s College, on the mathematical results of a mixture of elastic fluids (as air and vapour in the atmosphere), and on the theory of heat. With regard to the latter subject, the object was to show that there is a translation backwards or forwards of the calorific particles, consequent on and varying in intensity with the transverse vibration. Mr. Hopkins made some statements respecting experiments recently made on the temperature of mines and the doctrine of central heat. Mr. Airy gave an account of ob- servations of temperature made during the great solar eclipse of May 15th. XV. Intelligence and Miscellaneous Articles. ON THE FEEBLE ATTRACTION OF THE ELECTRO-MAGNET FOR SMALL PARTICLES OF IRON AT SHORT DISTANCES. To the Editors of the Philosophical Magazine and Journal. GENTLEMEN, tas enormous sustaining power of the electro-magnet has for some time been exhibited as a matter of great curiosity, but its very feeble attraction for small particles of iron at short distances is not, I believe, very generally known. This fact was first mentioned to me by Mr. Clarke, magnetical instrument-maker, which since then I have frequently noticed myself. Iam not aware that any explanation of this seeming anomaly has as yet been given; I have therefore ventured to offer one, which, if considered satisfactory, and of interest sufficient to deserve a place in your valuable Journal, I shall be obliged by its insertion. It will be necessary first to observe the phenomena which take place when a piece of soft iron is under the influence of the ordinary horseshoe magnet. When the arma- ture s'n' is brought near to the magnet NS, magnetism is induced in s'n'; and according to the law of magnetic induction each extremity of s'n! has its state of polarity opposite to that of the adjacent pole of the magnet NS, anda tendency to approach each other immediately s takes place, and if the force of attraction be AVeamaeme >) sufficient to overcome the inertia of s‘n', con- tact will instantly follow. If the armature be sufficiently massive to receive all the mag- Intelligence and Miscellaneous Articles. 73 netism NS is capable of inducing, the magnet will not be able to sustain any more, and consequently a limit to its inducing power must exist. The reaction of the armature upon the magnet will also strengthen the adhesion between them: probably the effect of this reaction will be influenced by the facility with which magnetism permeates the steel of which the magnet is made, and be greater in the softer kinds of steel. If this view be correct, the sustaining power of a common mag- net cannot be considered as an exact measure of its magnetic in- tensity. When a piece of soft iron is placed at a short distance from the poles of an electro-magnet, under the influence of a galvanic cur- rent, a comparatively trivial effect is produced, showing that the magnet thus induced is but of feeble magnetic intensity. This is owing, probably, to the facility with which soft iron is permeated by magnetism, and consequently any considerable accumulation prevented. But when the iron Is In contact with the poles of the electro-magnet, the magnetism, instead of escaping, will induce in the armature polarity, and the armature reacting powerfully on the soft iron of the electro-magnet, and receiving continuous additions of magnetism from the galvanic current, will be attracted by the magnet with increasing force until the attraction between them be- comes immense. If the galvanic action be discontinued, the keeper will remain applied to the electro-magnet, though less firmly ; and after it has been removed nearly all the magnetism escapes. If this explanation be correct, it will be obvious that the electro- magnet will not be well adapted for the construction of magneto- electrical machines, in which the armature is made to rotate rapidly in front of the poles of the magnet without actual contact. Tam, &c. No. 1, Maze Pond, Borough, May 7, 1836. GeEoRGE RaIney. OBSERVATIONS ON THE SOLAR ECLIPSE OF MAY 15, 18363; AND ON THE AURORA BOREALIS OF APRIL 22, To the Editors of the Philosophical Magazine and Journal of Science. GENTLEMEN, I am well aware that you must have received various accounts of observations made during the late eclipse; nevertheless, I beg to trouble you with one or two made by myself at that time upon the possibility of seeing the lunar mountains on the round or unbroken side of the moon, although it may be presumed that an account of the singular appearance at the time of the annular phase has been transmitted to you. I saw the roughness of the moon’s edge from the beginning of the eclipse ; but at the time of the ring becoming nearly equal on the eastern and western sides its narrowest part was divided directly across in two places, the light of the sun passing between the mountains. This affords an excellent method of cal- culating the heights of the lunar mountains ; for it may be readily 74 Intelligence and Miscellaneous Articles. known of what breadth the narrowest part of the ring appeared at this place (about 54° 53’ 53'" N. and about 1° 24’ W.). The mountains fully covered it, and I believe were higher than it a little. This observation was made with a 42-inch reflector, (New- tonian) with 5°75 inches aperture. As I did not expect so rare a sight, and there was not time to get the wire or divided eye- piece micrometer after it was seen, I regret to say no measures were taken of the heights. I may mention another circumstance which was not overlooked, namely, the appearance of the solar spots during the eclipse, which afforded the most favourable opportunity of examining them to ad- vantage. My observations were made with the view of ascertaining whether any difference in shade could be seen similar to the lunar cavities, or whether anything which indicates a rise above the solar surface ; but not the least could be observed, or even imagined to be visible. ‘Though I have examined the solar spots regularly for ten or twelve years, I never saw them to greater advantage than on that occasion. I will close this letter with an observation upon the aurora bo- realis which was visible at this place on the 22nd of April 1836, at 10" 45" p.m. It appeared directly overhead in the form of a star of great magnitude of not less than 90 degrees diameter, with nu- merous rays shooting every way, those to the north appearing of a deep red colour. With attentive examination I could not dis- cover the least darting or motion of the rays at one time, which if so, is not easily accounted for by the principles of electricity. A very similar appearance is represented by a plate in the Journal of the Royal Institution. Your humble Servant, High Barns, near Sunderland, May 26, 1836. W. Errricx. BRITISH ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE. The next Meeting will be held at Bristol dnring the week com- mencing on Monday, August 22nd; the Members of the General Committee will assemble on the preceding Saturday. METEORS OBSERVED IN INDIA IN 1832. The following notices are derived from “ Extracts from a Journal of a Residence, and during several Journeys, in the Province of Behar, {in the years 1831 to 1834, By Mr. J. Stephenson,” which appear in the Number for December, of the Journal of the Asiatic Society of Bengal, vol. iv. p. 713. Beautiful Meteor observed near Singhea, Tirhut, April \1th, 1832. At 4 hours 45 minutes A.M. and at daybreak, observed a meteor inthe form of a globular ball of fire, which passed through the air, from west to east, in a horizontal direction, and with a motion mo- derately rapid. Its size appeared to be about a foot in diameter, having a fiery train of the most splendid brilliancy apparently many yards long. It illuminated the country as far as the eye could reach, and remained visible for five seconds, after which it exploded Intelligence and Miscellaneous Articles. 75 like a rocket throwing off numerous corruscations of intense light; but without any report or noise of any kind. Its apparent eleva- tion inconsiderable. Another beautiful Meteor observed at the same Village on the 20th of May, 1832. At 6 hours 40 minutes p.m. a large pear-shaped meteor was ob- served shooting very rapidly in a horizontal position, and ina direc. tion from north to south. Nothing could exceed the brilliant mix- ture of green, tinged with blue colours, exhibited during its rapid progress. It left a luminous train of great length behind, and re- mained visible about three seconds, then disappeared in the southern horizon, without exhibiting any signs of exploding. ANALYSIS OF PLOMBGOMME. BY M. DUFRESNOY. The compound of oxide of lead and alumina, called by mineralo- gists plombgomme, on account of its resemblance to drops of gum which exude from trees, has hitherto been found only in Huelgoat mine in Brittany. It has, however, lately occurred in a lead mine near Beaujeu : it is found in small mammillated masses, with slightly varying textures ; some are of a yellowish white colour, externally very shining, and the fracture is both splintery and testaceous, with- out any trace of crystallization ; others are slightly greenish, com- posed of concentric layers, and possess a radiated structure, like wavellite. When observed with a microscope, the fibres appear to be crystalline, with a rhombic fracture, like some arragonites. The hardness of plombgomme is intermediate as to that of carbo- nate and phosphate of lime. Its specific gravity is 4-88 : before the blowpipe it decrepitates ; on charcoal it swells and yields a scoria- ceous white enamel. By analysis it yielded 1 i ea A SE Ee IE 211 Alumina ,...... onic asp ected Deutoxide of lead. ........43°42 Phosphoric acid .......... 1°89 NN ci a oc 16°14 100:00 The specimen subjected to analysis contained phosphate of lead: it is very probable that the phosphoric acid found indicates a certain quantity of phosphate of lead mixed with the plombgomme. On this supposition, the analysis should be thus stated : PUG S cin ales ania nnlqs.eiciste 20h PUTIN fir ).54 we 4760 —_—__—— -- 988:3 Howber Hill .. .. 474:0 —_—___——. we 992-2 Se Ao CABREL) Gt. Almias Cliff .. 10017 shh 2 prints: haan Symon Seat .. .-- 993-2 Rumbles Moor.. .. 481:4(a) — sate dee O924 oo .. 487:3 eee ee —o «- 491°7 (a) Pendle wo fm aeeens O94:3 —-_- .- 492°0 Draughton Moor tx | 9887 ——_—— .. 491°8 ea oo OO ——-— —_— .. 4948 — .. 988°5 Symon Seat .. .. 487°1 Flasby Fell eae. 98G:8 en alter peti tel LILI. Halton Height .. .. 985°4 Pendle .. .. -. 4869 —_—— -- 985°6 Draughton Moor .. 480-0 Ingleborough tere iett ee. ——_... 4868 Mean .. —990°5 — .. 4858 Ht.ofGt.Whernside 2320-8 Flasby Fell .. .. 480°4 —— Rumbles Moor 13303 Kilnsey Moor .. -. ane Becuy iaclchoncipeeys Aeetus. Halton Height « & ie Mans Mean ee ee 1330°5 ip Mars i $5 as 483:°6 Ingleborough above Pendle Hill. ee * : : ae % At Great Whernside .. 538°8 Penygent oy wap Abo —_—_—_—_———_ ..._ 5493 ae Hill 4. 4729 age ee OG) Mea 481-6 Arneliff M x . an Height of Gt. Whernside2320: 8 rncli OGR wes cetpe sre : Settronside os ae POOLE Pendle Hill . .1839°2 ae Moor 3 ~~ eee ae Pendle Hill above Rumbles Moor. — .. 551:4(a) At Great Whernside .. 518°0 — B64 a .. 5088 (a) aes eon eR) 509°7 — -. 5493 _ -- 5090 — a .. 5601 Arncliff Moor .. .. 5063 Symon Seat .. .. 5442 Settronside .. .. 5057 Pendle Hill tern BAO Howber Hill .. .. 5123 Ingleborough .. .. 536°7 oo ee rages owen 5 te BER Oe, ———_—... .. 5107 Penygent .. .. 5453 Rumbles Moor.. .. 5114 Knoutberry Hill -- 5403 —— .. ww S04 Smearsitt Sel cee OAL ——.. .. 5069 Ment) fc Seapm: |) 0 Saeco e Height of Ingleborough 2384°5 sa Lae asd hc a ne — Pendle Hill 1839:0 Symon Seat .. .. 5053 Great Whernside above Pendle Hill. Pendle Hill is ; . ae AtGreat Whernside .. 469°9 Draughton Moor .. 5088 -- 4/96 —_— AS M2227 —_————- ...__ 4766 502-7 ee oy ARB Lippersley Pike.. .. 511-0 Rumbles Moor, Pendle Hill, and Boulsworth. 99 Feet. Feet. AtFlasby Fell oe « 5064 Arncliff Moor .. .. 381:4 Halton Height .. 5045 Howber Hill dd, worsens FE)S4 ga vee | 0:0 —_—__-— Fo 376 Ingleborough .. .. 5193 Rumbles Moor .. .. 369°6 Mean .. +507°3 TD UE ee Heightof Rumbles Moor 1330-5 = pees Rabe tsk ——— Pendle Hill .. 1837-8 The Chevin .. .«. thy Pendle Hill by Inglebro” 1839-0 Symon Seat... sine — Gt.Whernside 1839-2 Pendle te ee ae Rumbles Moor 1837'8 Draughton Moor... Hoe WMeanicocinaatres 1838°7* Lippersley Pike : : 380-8 Hal Height .. .. 3742 Ingleborough above Boulsworth. alton Heigh Sn ot sale AtGreatWhernside .. 6747 Mean.) .. -La768 Arncliff Moor .. -- 667-0 Height of Rumbles Moor1330-5 Rumbles Moor .. .- Hee a (a) Ee eikeodh. Wait Symon Str ur pane Pendle above Boulsworth. Pendle .. «. «+ 665°5 {AtGreatWhernside: .. 126°7 —6765 Arncliff Moor .. .. 125°0 Height of Ingleborough 2384°5 Howber Hill .. .. 129°6 (a) E RAD — _ we ne 1846 Se ee A Rumbles Maog!'s. 1.) 1388 Great Whernside above Boulsworth.| ~~ *"—** ; be AtGreat Whernside .. 6089 Symon Seat .. .. 135°7 Arncliff Moor .. -- 6086 | Pendle , .. .. .. 1245 Howber Hill .. .. 6104(a)) Draughton Moor .. 1343 ir me 611°5 eee BE eS ee 128-0 Rumbles Moor .. .. 621°1 Lippersley Pike .. 130-2 ——-—— .. .. 625-0 Halton Height .. .. 1303 waa toe GLO ee een Symon Seat OLE Mean... —129°3" Pendle .. «- -- Gll'4 | Height of Pendle .. 1838-7 Draughton Moor .. 614-2 Boul bi aed LS Sunn Tee 6148 ——— Boulswort 709°4 Halton Height .. .. ee Boulsworth by Inglebro’ 1708-0 —— Great Whernsidel707:2 Rumbles Moor 1707:3 Pendle... .. 1709°4 Mean .. .. 17080 Mean .. .. 6136 Height of Gt. Whernside 2320-8 Boulsworth 1707-2 Boulsworth above Rumbles Moor, At Great Whernside .. 382:3 It will be seen from the following statement, that Colonel Mudge’s measurements of the above altitudes (above mean low water, spring tides,) are invariably less than mine. * This height is exclusive of the Beacon hillock (about 7 or 8 feet high). M2 100 Mr. Lubbock on a Property of the Parabola. Mudge. | Nixon. Diff. Ingleborough ........+++++eeeee) 2361 | 23845 | + 23°5 Great Whernside ......-++--«| 2263 | 2320°8 | +57°8 Whernside (in Ingleton Fells)| 2384 | 2426-0 | +42°0 Pendle Hill .........cceceesereee] 1824) 1838°7 | 4+14°7 Boulsworth Hill ..... sscocesees| L689 | “170820 | +- ¥9°O Rumbles Moor.....cccccceceseee| 1308.| 1330°5 | +22°5 Ilkley, May 24, 1836. Joun Nixon. XXII. Ona Property of the Parabola. By J. W.Lussocx, Esq.) F.R.S.+ N the 8th volume of Gergonne’s Annales de Mathéma- tiques, p. 9, M. Poncelet has given the following theorem : “ Un triangle étant circonscrit a une parabole, si on lui circonscrit & son tour une circonférence de cercle, elle passera necessairement par le foyer méme de la courbe.” See also a paper by M. Steiner in the 19th volume of the same work. The proofs which have been given of this elegant property of the parabola are indirect, and however ingenious they may be, it seems desirable to show how the theorem in ques- tion may be deduced immediately from the equation to the curve. The general methods of analytical geometry may be deemed incomplete and imperfect while they do not embrace questions of this nature, and their great advantage is liable to be overlooked. Let A B C be a triangle, and let 21, 5 25 Yo. X31 Y3> be the coordinates of the points A, B,C. I propose to prove that if the lines A B, B C, A C touch a parabola the focus of the parabola is in the circumference of the circumscribing circle A B C. ; The equation to any straight line passing through given points (2,5 %)> (72> Yo) is q — yn, = LEH (a.m) | The equation to the tangent passing through the poin (2,, y;) and touching a curve in the point (2, y) is d YY a= ae (x — 2). This equation is generally given for rectangular coordinates * This height is probably inclusive of the Beacon hillock. + Communicated by the Author. Mr. Lubbock on a Property of the Parabola. 101 only, but the reasoning by which it is established is equally applicable to coordinates inclined to each other at any angle. Let y? = 2p be the equation to a parabola referred to any coordinuate axes Oz, Oy oblique or rectangular. y=Vq c=PV, p=2SP. (See Bridge’s Conic Sec- tions, p. 15.) dy a iP Sea ae din | ay 2\—2y if the tangent passes through (2, y,), (725 Yo)- Pp. (%,—2)° Whee SS See ile ATP 2 (Ly Yo—Xoy\) ny Similarly, See pa eg ae Bae (234; —2) Ys) fe Lg—23)* ny = Fad : (3) 2 (%2Y3—23Yo) By making the diameter of the parabola Oz pass through the point A, I may hereafter make y, = 0, without limiting the generality of the question. Subtracting (2.) from (1.); 2 (Y3—Yo) (Yg+ Yo) FM (LiYo— Lo Yi — 2 Ygt L3y1) ie 2 P (#34 XQ) (X13 — Xp) (%3Yo—LoY3— Xi Y3—Xy Yo) = 2Y, (2 Y3— Xs Yo) (®y Yo— LY, —% Ygt+ 23%) (4.) Hence if y, = 0 (22, —x_—3) (x3 — 2g) @gtX2=O0 or «r3—2%, = 0 OF 2X3 Yg—TMg Yg tL Yg—*%) Yo = 0. In the second case y,—y3 = 0; and since x, = 2 Y3 = Yq the points (72, Yo), (43s Y3)y coincide and are identical ; in the third case the points (2,5 Y,), (#5 Yo) (#35 Ys) are in the same straight line ; it is useless therefore to consider these cases, and it is sufficient to take the first case only, namely, when ¥, = 0, and #342, = 0. Let X, Y be the coordinates of the centre and # the ra- . dius of the circumscribing circle passing through the points (415 Y)s (#5 Yo) (#55 Ys), then by the equation to the circle, | (@i—X)P4(yi— YP+2 (4—X) (ys ¥) cos wy = BP (a,—X)? + (yo— Y)?+2 (x2—X) (y.— Y) cosry = R*, 102 Mr. Lubbock on a Property of the Parabola. Subtracting the latter equation from the former, I find an equation which may be written as follows: (v1 +2,—2 X) (a1 —%g+ (¥,—Ye) Cos xy) +(%+Ye—2 Y) (Yi— Yat (H1— 4g) cos wy) = O. Substituting in this equation for y,—y, its value Pp (Yy —2,)? 2 (1 Y.— Te) and dividing by x,—2,, (See p. 101). (x, +2,—2 X) (2) Yo — TY + i (x,—2,) cos xy) + (y,+4¥.—2 Y) (4 (%, —25) + (2, Yo—X_ 41) COS ry) = 0, which equation may be written in the form {ai+2%g+%3+ £ —2X + (Yi +¥2t+Ys—2 Y) cos xy} (2, Y2— Lys) +2 | {(aite,)oosay—2¥—2 Xcosxy}(X, +22) + Xi Y, — 29} (a3 + yg COSEY) (L,Y.—Lyy,) = O. (5.) and also by symmetry, since the three points (2,5 Y;)) (®2» Y.)> (35 y3) are similarly related, {%+234+2,+ £ —2X +(Yot+¥st ¥i:—2 Y) cosxy} (%2 43 —23 Yo) a Ey Meaty) cos xy—2 Y—2 X cos ry} (x,— 43) +m 8.4| —(2,+y, cos Ly) (X2¥3—X3 Yo) = O (6.) { (ata, 4 + £ —2X +(¥s+ ¥+Ye2—2 Y) cos xy} (x34; —21 Ys) +24 ((ayteideos xy—2Y—2X cos xy}(x%3—x, +(#3Y¥3—“y, } — (+ Yq C08 &Y) (%3Y;—2, Ys) = O- Adding together the three last equations, many terms de- stroy each other, and Mr. Lubbock on a Property of the Parabola. 103 {a.ta,tayt £ —2X+ (y¥,+ Yt Ys—2 Y) cos ry} {21 Yo— Bo Yi + X3Y,— 2X Yg+XoYy— U3 Y2} = 0. (7-) Unless the three points (2,4), (a5 Yo) (35 Y3) are in the same straight line 2, +H9+23+ See +(y+y.+y3—2 Y) cosxy = 0. (8.) 2 This equation is general, but simplifications result if y, = 0; (which supposition does not limit the generality of the solu- tion of the problem proposed ;) and in this case by p. 101, line 18, w,+2; = 0, x, = —x3, equation (8.) becomes a + 2 -2X+(y+ys—2Y) cosy = 0. (9.) and by equation (7.), ((z,- £) (Yo+ Ys) + p(¥+Xcosxy) = 0. (10.) If Aa?+ Bey + Cy+ De+HEy+F=0, is the equation to any curve of the second order, the free re- sult generally from the intersection of the lines whose equa- tions are, (B?—4 AC) (2?—y?)+(2 BE—4 DC) «—(2BD—-4EA) y +FP?—-4CF-D’414AF=0. ( B°—4 AC) (2°—y*?)+(B D—-2 AC) x+(BD—2 DC)y +2BF—ED-— {(B—-4dAC) y+ (2BD—-4AE) y + D*—4 A E} cosry = 0. (See Phil. Mag. Aug. 1831.) If the equation to the curve is 7? = 2p 2, in which case m=O, laa 0, C= 1, == og fi = OF '0zit 1s easy to deduce from the equations given above, or to prove otherwise, that the focus results from the intersection of the straight lines whose equations are x = - and y = —p cos xy. & q 9 Y P ¥ Let x,,y, denote the coordinates of the intersection of the circumscribing circle passing through (2, , ¥,), (os Yo)s (3243) with the line Pp D c= a, = se 2? 2 In order to prove that the circle passes through the focus of the parabola it is sufficient to show that y, = —p cos ry. By the equation to the circle 2 (4 _ X) +(y,— Y)+2 (4 —X) (yy— Y)cosry = R* (v,—X)?+ Y¥?—2(2#,—X) Yeosry =F 104 Mr, Rudge on the Position Sincey, = 0. Subtracting the latter equation from the former ( +2 —2X) (7.— f — y,cos xy) +(y,—2 Y) (—y.+ (2, — -) cos xy) = 0, which equation may be written as follows : (1 = F) (x, 4 £ —2X—2 Y cos ry) —pcosxy(Y¥ + X cos ry) —(y,+ poosxy) (y,—-2Y-2 Xcos ry) = 0. By equation (9.) t+ £ —24+X(y,+y3—2 Y) cosry = 0; hence { (2, r 2) (yoy) + P(X +X cosy} cos ry — (y,+ pcos xy) (Y¥y— 2 Y—2Xcosry) = 0. Also by equation (10.) (7.—4) (Yo+ Ys) + p(¥+Xcos xy) = 0; hence (y, + pcos xy) (y,s—-2 Y—2Xcos ry) = 0 ¥4= —pcosxy, or y,=2Y+2Xcos ry, and it is evident that the czrcumscribing circle passes through the focus of the parabola. XXIII. On the Position of the South Magnetic Pole. By Epwarp Runes, Esq., F.R.S., 8.A., LS. 5 H.S.* THE experiments detailed by Captain James Clark Ross, R.N., &c., which led to the important discovery of the north magnetic pole, and which are published in the Philo- sophical Transactions for the year 1834, suggested to me as an object of interesting inquiry, whether any similar affection of the horizontal magnetic needle had ever been noticed by’ any former navigator of the southern hemisphere, from which an approach to the magnetic south pole could be surmised. No such appearances seem to have been observed by Anson, or any one after him; but prior to his circumnavigation of the globe, Captain Abel Tasman, who was appointed for the dis- covery of southern countries by direction of the Dutch East India Company, sailed from Batavia with two vessels on the * Read before the Royal Society, Feb. 19, 1835; and now communi- cated by the Author. “of the South Magnetic Pole. 105 14th of August 1642, in his account of the voyage, gives the following particulars of an observation made on the 22nd of November of the same year, when by a prior and subsequent observation of November the 15th and 24th, he was in about latitude 43° S., and longitude from Paris 160°. ‘“« The needle was in continual motion without resting upon any of the eight points of the compass,” which he says, * led him to conjecture that there were some mines of loadstone on that spot.” Tasman’s Journal, written in Low Dutch, is now an ex- tremely rare book: a translation of it is given in Dr. Hooke’s Philosophical Tracts, p. 179, for the year 1682; in Nar- borough’s and in Correal’s Collections of Voyages; and also by Harris, who gives a new translation of it in the second edition of his Collection of Voyages, where, although he no- tices Dr. Halley’s theory of the magnetic poles, which was published in 1683, he does not seem to suspect that ‘Tasman’s observation of this very remarkable affection of the magnetic needle was made in the immediate vicinity of the south mag- netic pole, at that period in that particular situation, ascer- tained by the horizontal needle only; the dipping-needle, in- vented by Norman in 1681, being then unknown. Dr. Halley was of opinion that the north magnetic pole was not far from Baffin’s Bay, and that the south magnetic pole was in the Indian Ocean, south-west from New Zealand; whether he had availed himself of the observation made by Tasman in forming this opinion, does not appear. Euler places the north mag- netic pole for the year 1757 in latitude 76° north, and longi- tude 96° west from Teneriffe; and the south magnetic pole in latitude 58° south, and longitude 158° west from Teneriffe. It has been ascertained by observation, that the magnetic poles were on the meridian of the poles of the earth at London in the year 1657, being fifteen years after ‘l'asman’s observa- tions, and that it reached its utmost degree of variation west in the year 1818, when it became stationary at 24° 26! west, and has since in respect of London been retrograding towards the east, completing one quarter of the circle round the poles of the earth in 161 years at the rate of 11 or 12 minutes of a degree in a year; so that, presuming Tasman was on the south magnetic pole on the 22nd of November 1642, it would now be found in or about the forty-third parallel of south latitude to the south-east of the island of Madagascar, a convenient situation, when compared with that of the north magnetic pole for ascertaining the exact position of the south magnetic pole, and where experiments with the horizontal- and dipping- needles to lead to its discovery and determine the comparative intensity of the south magnetic power might with facility be Third Series, Vol.9. No. 52. Aug. 1836. N 106 On the Position of the South Magnetic Pole. made. In pursuance of this desirable object the progress of the south magnetic pole might be accurately ascertained by annual observations; whether its distance from the south pole of the earth is uniform in its progress and if in an exact opposite direction to the north magnetic pole; to trace the point at which the axis of the magnetic poles crosses that of the earth; and thus by a continued series of observations and experiments a wide field might be opened to enlarge our hitherto imperfect knowledge of this mysterious power, which might be considered of so much importance in guiding and directing the motion of the earth on its axis and in its orbit. Table of the Observations on the Magnetic Needle made by Captain Joun ABEL Tasman from the beginning to the ter- mination of his Voyage; extracted from his Journal. Longitude Variation of the Time. Latitude. from Paris, Needle. 1642. Oct. 8 to 22. | 40°40'S,) ......... 23° 24°RQ5°W. 22. | 49 47 89° 44! |269 45 W. Nov. 6. | 49 4 114 56 |26 15. | 44 3 140 32 {18 30 W. OEE eens ssince 158 4 W. Bas || séesescay | esatescon lle addeacdabac The needle in conti- nual agitation. 24, | 42 25 TGSPOO I ge.cacese cons The needle pointed towards the land, now first discovered and called Van Die- men’s Land. _ March 2.| 911 192 46 14, | 10 12 186 14 20.} 5 15 181 16 25. | 4 35 175 10 April 1. | 4 30 171 2 12.} 3 45 167 14.| 5 27 166 57 | 915 20.| 5 4 164 27 | 8 30 May 12.| 0 54 153 17 | 6 30 18. | 0 26 147 55 | 5 30 RB. 27. | 6 12S.| 127 18 |Returned to Batavia after 10 months’ absence, having sailed round the Australian continent without seeing any part of it but the extremity of Van Diemen’s Land. Dec. 1. | 43 10 167 55 | 3 E. {Frederick Henry bay, Van Diemen’s Land 9. | 42 37 176 29 | 5 E. New Zealand. 18. | 40 50 191 41 | 9 Ee 1643. January 8. | 30 25 192 20 | 9 12. | 30 5 195 27 | 9 30 16. | 26 29 199 32 | 8 19, | 22 35 204 15 | 7 30 21. | 21 20 205 29 | 7 25 25, | 20 15 206 19 | 6 20 0 8 9 9 8 0 on Ee ed be ed ted dt a dt dt [eS 16aaty XXIV. On Fluorine. By G.J. Knox, Esq., and the Rev. Tuomas Kwnox.* AS’ far as the existence of a substance which had not hitherto been procured in an independent state could be deter- mined, the experiments and reasoning of Davy and Berzelius are sufficiently conclusive. ‘The only desideratum seems to have been the obtaining a vessel upon which this energetic principle would exert no action. Since fluorine shows no affi- nity for the negative elements oxygen, chlorine, iodine, and bromine, nor for carbon or nitrogen, it would appear that the vessel to contain it should consist of some solid compound of those substances; but as such vessels would be unable to bear exposure to a high temperature, we considered that though they might be convenient for retaining the gas when once obtained, they would not answer for its production. It was therefore necessary to employ some substance already saturated with the element; and for this purpose fluor spar, from bearing exposure to a high temperature and being easily formed into vessels, appeared best adapted. The most con- venient method of obtaining the gas seemed to be by acting upon fluoride of mercury with dry chlorine, by which means, if the absence of moisture could be insured and the forma- tion of a chloride of mercury obtained, fluorine must have been disengaged, and if present would be recognised by ap- propriate tests. Placing dry fluoride of mercury in the fluor-spar vessel, we heated it till a glass plate cooled by the evaporation of sul- phuret of carbon showed no trace of moisture in the vessel ; the chlorine was then passed through a desiccating tube filled with fused chloride of calcium, the tube being bent at an angle, and its extremity drawn capillary, so as to enter the vessel, which, when filled with the gas, had its orifice closed with a plate of fluor spar which was fastened firmly down. After exposing it to the heat of a spirit-lamp for some time, on removing the fluor spar cover, and replacing it rapidly with one of silica, it showed immediate and powerful action. The inside of the vessel was found on examination to be co- vered with crystals of bichloride of mercury; both of which results prove the presence of either fluorine or hydrofluoric acid; to determine which, we repeated the experiment, cooling the cover of the vessel so as to condense any hydro- fluoric acid which might be present, but none appeared, from * Communicated by the Authors. N2 108 Mr. J. G. and the Rev. T. Knox on Fluorine. which we inferred that fluorine and not hydrofluoric acid had been present in the vessel, which was also further confirmed by the absence of fumes when the vessel and its contents had been previously dried. Placing inverted over the orifice of the vessel a clear cry- stal of fluor spar, with a small perforation in the centre into which a stopper of fluor spar fitted accurately, on the stopper falling into the vessel the tube was filled with a yellowish green gas, the colour of which deepened with heat, and dis- appeared when cold. On reheating the vessel below, the gas rose again into the crystal above. On removing the crystal while hot to a wet glass plate, it flew to pieces, which pre- vented us from determining whether the coloured gas was bi- chloride of mercury under heat and pressure, hydrofluoric acid, or fluorine. Having procured Jarger vessels with receivers into which ground stoppers were made to fit accurately, we resumed in the present month the experiments we had tried in the be- ginning of April. Ist Exp. We heated fluoride of lead with oxygen, and afterwards with dry chlorine without action upon the fluoride. When the receiver (its stopper having fallen into the vessel below) was placed over gold-leaf, a chloride of gold was formed. 2nd Exp. Treating hydrofluate of ammonia similarly with chlorine, there was strong action on glass and formation of chloride of gold as before. 3rd Exp. Treating fluoride of mercury with chlorine (as we had done in our former experiments), we obtained crystals of bichloride of mercury in the vessel. Leaving the receiver over gold-leaf, there was after a considerable time action on it, producing a yellowish brown appearance. This we placed ona slip of glass, and on adding a few drops of sulphuric acid and evaporating to dryness there was very strong action on the glass where the gold had been, proving that it was a fluoride of gold, and that since gold is not acted on by hydrofluoric acid there must have been fluorine in the receiver. As an addi-. tional corroboration there was no hydrogen in the tube, which there would have been had hydrofluoric acid been decom- posed by the gold. From these experiments we conclude that fluorine was present in the receiver, but whether a slight trace of hydrofluoric acid (to which the action on glass was due) may not have been present with it, we have not yet determined. We hope on a future occasion to be able to give particulars with regard to the properties of the gas; but we consider that Mr. G. Bird on certain new Combinations of Albumen. 109 the present results are sufficiently important to justify us in submitting them to the public through the medium of your Magazine. We remain, Gentlemen, yours, &Xc. Toomavara, Tipperary, T. Knox, July 1836. Geo. J. Knox. Explanation of Figures. Fig. 1. The vessel with the receiver in the stand which holds down the receiver by means of spiral springs A. Fig. 2. Vessel with cover off, showing the orifice and the small depressions in which the gold-leaf, &c. were placed. Fig. 3. Receiver without stopper. Fig. 4. The stopper. Fig. 2. XXV. On certain new Combinations of Albumen, with an Account of some curious Properties peculiar to that Substance. By Gouvine Birp, F.L.S., F.G.S., Senior Fellow of the Physical Society of Gus Hospital, §c.* 1. JN the course of the following observations I shall avoid any unnecessary reiteration of facts already well known to chemists, and confine myself to referring to them only when they are required to explain any circumstances con- nected with those new modifications or combinations of albu- men which have fallen under my notice. Our knowledge of the properties of albumen, although more extended than that * Communicated by the Author. 110 Mr. G. Bird on certain new Combinations of Albumen, of most other animal matters, is nevertheless very limited, which limitation arises, in all probability, from its compara- tively weak affinity for other bodies, which prevents our be- coming acquainted with anything like very prominent or in- teresting features; I am however convinced that the study of the chemical nature of albumen will reward the. investigator with a richer harvest of facts than that of any of the other proximate constituents of the animal frame, as well from its. prevalence under some modification or other in every secre- tion in the body, as from its being the chief constituent of the circulating fluid, and constituting, if I may be allowed the ex- pression, the type of the albuminous principles ( properly so called) of the blood, and the pabulum from which the different secretions are formed and the waste of the body repaired. Indeed, by a synthetic method, founded to a certain extent upon some of the novel properties of albumen I am about to mention, I trust to be able in a future paper to prove that many, if not all the secretions contain albumen, although its presence has not been suspected, or if suspected not detected, and that they are indebted to the presence of a peculiar com- bination of this principle for many of their most prominent characters. In the course of my investigations I had fre- quently occasion to observe that albumen procured from dif- ferent sources frequently differed slightly in its behaviour to reagents, and an ignorance of this fact led at first to consider- able discrepancy in the results of my experiments; thus I may observe that the white of egg and the albuminous secretions of serous surfaces very closely resembled each other, but dif- fered in degree of solubility and many other minor properties from the albumen of serum of blood, which I have generally made the subject of my experiments, aiter freeing it from fat by agitation with sulphuric zther; and to this form of albu- men I shall constantly refer in the course of the following ob- servations. . 2. Some serum freed from fat (1.) was mixed with a sufficient quantity of a solution of pure soda to cause it strongly to af- fect turmeric paper; the heat of a water-bath was applied, the mixture being constantly stirred: in a short time it appeared to solidify, forming a pale yellowish transparent jelly which scarcely at all affected turmeric paper. Distilled water being then added, and heat again applied, a nearly limpid, but some- what mucilaginous solution of albuminate of soda resulted, which became quite transparent by filtration; it was not at all affected by boiling or the addition of alcohol, but was precipi- tated by the acids, solutions of chlorine, alum, acetate of lead, bichlorides of iron and mercury, sulphate of copper, ferro- with an Account of some curious Properties of that Substance. 111 cyanate of potash (after the addition of acetic acid), and tinc- ture of galls; reactions quite characteristic of solutions of al- kaline albuminates. 3. A solution of albuminate of soda (2.) was diluted con- siderably with cold distilled water and placed in a tall cylindri- cal glass vessel; through this fluid a current of carbonic acid gas was passed, the tube from which the gas issued being suffi- ciently long to reach the bottom of the vessel: in a few minutes the fluid, before transparent, became opake, and rapidly de- posited a copious precipitate of albumen in the state of a beau- tifully white, impalpable powder ; the acid gas being allowed to pass for some time, longer, the precipitate gradually disap- peared until the whole was as limpid as before the experiment. The solution thus obtained was acid, and consequently red- dened litmus-paper, whereas before the experiment it red- dened turmeric; it afforded a copious deposit with those re- agents which precipitate solutions of albumen in mere water, or when dissolved by acids, but not with those which affect solutions of albumen in the alkalies only: thus, ebullition caused a considerable deposit, as also did nitric acid, tincture of galls, bichloride of mercury, and alum; whereas the dilute acidsand perchloride of iron did not disturb the limpidity of the fluid, although, as before stated, prior to the passage of the acid gas they produced copious precipitates. Heat, I have already stated, caused a considerable deposit of albumen in the same manner as from a mere aqueous solution of albumen which had not undergone coagulation, but differed in requir- ing a higher temperature, a full boiling-heat being necessary to produce a considerable precipitate. Ammonia when very dilute caused a precipitate also, which readily dissolved in an excess of the precipitant; the action of heat was of course ac- companied with a copious evolution of carbonic acid gas. From these facts I was induced to conclude that the albumen previously existing in combination with the soda, had left that alkali to combine with the carbonic acid, thus playing the part of a base or electro-positive element, leaving the soda in the state of bicarbonate, that salt being of course formed by the action of the carbonic acid added: the solution might thus be supposed to contain a mixture of the carbonates of soda and albumen with an excess of carbonic acid. To this explanation it might be objected, that as alkaline bicarbonates are known to dissolve albumen, the acid gas had only converted the alkaliinto a bicarbonate, which thus held the albumen in solu- tion: if this were true, how can the precipitation of albumen on the first passage of the gas be explained, unless it be sup- posed that the neutral alkaline carbonate which is first formed, 112 Mr.G. Bird on certain new Combinations of Albumen, is incapable of holding in solution so large a quantity of al- bumen as the free alkali, or its bicarbonate ; an assumption directly opposed to fact, as I shall have occasion to show in another place : besides which, the action of reagents ought to differ, and instead of those only which precipitate acid solu- tions of albumen producing a turbidity, a troubling should be produced by those also which affect its alkaline solution, for surely the solution of an animal matter in a carbonated alkali approaches less to the nature ofan acid than to that of an al- kaline solution. 4. I next attempted to form a solution of albumen in car- bonic acid, excluding the agency of alkali, which if successful would, I considered, at once demonstrate the real nature of the combination; but in this I experienced considerable diffi- culty, for when a current of carbonic acid gas was passed through an aqueous solution of albumen (1.), no distinct com- bination was obtained ; and on attempting in a similar manner to dissolve albumen previously coagulated by the action of heat or acids, I failed to obtain satisfactory results, from the close state of aggregation in which the albumen was obtained appearing to present a considerable resistance to the solvent action of the acid. I at length succeeded by precipitating al- bumen from serum of blood by means of alcohol, well wash- ing the precipitate until all traces of alcohol were removed, (the vessel in which the precipitation was performed being immersed in ice-cold water to prevent the action of the evolved heat on the albumen,) carefully avoiding any unnecessary ex- posure to the air, which, by drying it, might serve to lessen ‘its solubility in the acid. A portion of this finely divided al- bumen was diffused through cold water, and submitted to the action of a current of carbonic acid gas; after a short time it entirely dissolved ; but the solution was not perfectly limpid, nor did it become so by filtration. In preparing this solution care must be taken to add a sufficient quantity of water, otherwise a considerable quantity of albumen will be carried mechani- cally out of the fluid by each bubble of gas, and being depo- sited on the sides of the vessel, will dry rapidly, and on being returned to the fluid will be found to have lost much of its solubility in the acid; and it is very remarkable how large a quantity of albumen can (by this kind of inverted filtration) be carried beyond the influence of the gas. ‘The finely divided albumen obtained by passing a limited quantity of carbonic acid into albuminate of soda (2.), after well washing, may be substituted for that precipitated by alcohol, although it must be observed that it is not quite so readily soluble as that ob- tained by the latter process, owing to its having undergone with an Account of some curious Properties of that Substance. 113. some modification, probably in its state of aggregation, diffi- cult to unravel. If the precipitated albumen is merely digested in an aqueous solution of carbonic acid in a closed flask for some hours, as much appears to be taken up as if a current of the gas was used; and hence | have been led to conclude that the solubility of the albumen is not so much owing to the for- mation of a definite soluble compound (carbonate ?) as to its being merely dissolved in the quantity of acid gas which water is capable of holding in solution at ordinary atmospherical pressure and temperature. 5. The solution of albumen in carbonic acid behaves to re- agents like a mere aqueous solution, —as dilute serum of blood, with, as far as I know, a single exception, and this is the action of very dilute ammonia, which produces a precipitate of albu-, men soluble in an excess of the alkali. Heat produces a de- posit of albumen with a simultaneous evolution of carbonic acid gas; nitric acid, tincture of galls, acidulated ferrocyanate of potassa, and bichloride of mercury all produce copious pre- cipitates. By exposure to the air it does not very readily be- come turbid, the carbonic acid being very slowly evolved: after the Japse of a week, however, the albumen is deposited in a white impalpable form. The presence of carbonic acid in these solutions of albumen appears to prevent its ready precipitation by nitric acid, several drops being required to produce a considerable troubling; and on this account I am accustomed to use the nitrohydrochloric acid as a preferable precipitant when I have the detection of albumen in an animal fluid in view, as the action of this acid does not appear to be so liable to be affected by carbonic acid. 6. Wishing io ascertain with greater accuracy whether the albumen precipitated from its solution in soda by carbonic acid, depended for its resolution upon the formation of a com- pound with that acid, or upon the solvent action of the bicar- bonate necessarily formed, I availed myself of Dr. Stevens’s adaptation of Prof. Graham’s law of the diffusion of gases, by placing a glass vessel filled with the solution (3.) under a large receiver full of hydrogen gas inverted over water. In twelve hours the apparatus was examined, and the fluid sub- jected to experiment, previously quite limpid, was found to be very turbid from the deposition of its albumen; the carbonic acid having been abstracted by the hydrogen gas. A modi- fication of this experiment was then made by placing over the fluid subjected to the hydrogen gas, a capsule filled with lime-water : the carbonic acid being abstracted as before, was absorbed by the lime-water, causing the precipitation of car- Third Series. Vol. 9. No. 52. Aug. 1836. O 114 Mr. G, Bird on certain new Combinations of Albumen, bonate of lime, which occurring simultaneously with the pre- cipitation of albumen appeared to bear so near a relation to cause and effect that there can, I think, no longer remain 2 doubt as to the solvent nature of carbonic acid with regard to albumen. ‘These experiments prove moreover another inter- esting fact, viz. that however energetic a solvent for albumen the uncombined alkalies may be, their carbonates must be re- garded as comparatively powerless, contrary to the generally received opinion; for the same quantity of soda must neces- sarily have existed in the fluid after, as before its being sub- jected to the action of the carbonic acid, and subsequently of the hydrogen, the only difference being that it had become converted into a carbonate, whereas before the experiment it was pure and uncombined, quoad carbonic acid. 7. I was next desirous to ascertain what was the degree of solvent action capable of being exerted on coagulated albu- men by alkaline carbonates, and whether this solvent power depended upon any partial decomposition of the salt em- ployed, the acid or base being set free; I therefore precipi- tated albumen as before from fresh serum by means of alcohol, well washed it with cold distilled water, and divided it. into four portions which I placed in as many flasks, the first of which was filled up with a solution of bicarbonate of soda, the second with a solution of the carbonate of soda, the third with water impregnated with carbonic acid, and the fourth with recently boiled distilled water; they were allowed to di- gest for twelve hours, and then examined after filtration with the following reagents: Sol. of Alum,| Bichtoride of Mercury. Solvent Ebullition. Nitric Acid. | Acetic Acid. employed. : Precipitate : f 1. Bicarb. | Dense opa-| Copious | sol. in ex-| Copious | Copious soda. city. precipitate.| cess of | precipitate.| precipitate: acid. 2. Carb. soda. . Sol. of carbonic | Copious Do acid in | precipitate. 5 water. Opacity. Do. Do. 4, Recently boiled a water. The water in the fourth flask was used for the purpose of with an Account of some curious Properties of that Substance. 115 ascertaining whether the precipitated albumen contained any of the soluble form of that principle which might have been mechanically carried down with it, but that this was not the case was satisfactorily proved by the five reagents employed not in the least disturbing the limpidity of the filtered fluid. It will be observed that ebullition produced a copious troubling in the solution of bicarbonate of soda that had been digested on the albumen in the first flask, as if a portion of uncoagu- lated albumen had been present, which I have just shown was not the case. How then can it be accounted for? Might it not be suggested that the salt employed had been decom- posed into a neutral carbonate and free acid, which latter dis- solved a portion of albumen, the carbonate being also partially decomposed into free alkali, which by dissolving albumen formed an albuminate of soda, whilst the portion of carbonic acid deserted by its base united to another portion of albumen, and thus the solution might be supposed to consist of unde- composed carbonate of soda, albuminate of soda, and carbo- nate of albumen (if this expression may be provisionally ad- mitted). With regard to the contents of the second flask, in which the neutral carbonate was used, this appears to have undergone an analogous decomposition, for like the contents of the first flask, we find them present the same phenomena with reagents as would be produced by a mixture of solutions of albumen in carbonic acid and albuminate of soda; but ex- periments are required to clear up the obscurity enveloping this point. 8. An interesting field for investigation thus appeared to present itself in the examination of the action of albumen on the alkaline carbonates, the investigation of which I com- menced with great care, and obtained some highly interesting and unexpected results; but not having quite concluded my examination of this part of my subject in consequence of the multitudinous repetition of experiments required to obviate the various sources of fallacy peculiarly incident to investiga- tions in organic chemistry, I am compelled to defer their publicity for some weeks, when I trust to be able to commu- nicate some curious and important facts on this interesting subject. 44 Seymour-street, Euston-square, July 6, 1836. cr 116 J XXVI. Remarks on the Formula for the Dispersion of Light. By the Rev. Baven Powe1.L, M.A., F.R.S, Savilian Pro- fessor of Geometry, Oxford. (Continued from vol. viii. p. 309. ] N a former portion of these papers I have given some ac- count of the methods by which the formula of dispersion, or relation between the length of a wave and the velocity of its propagation, or the refractive index for a given ray and given medium, is made applicable in calculation. I have also illus- trated the comparison made by the researches which Sir Wm. R. Hamilton has given me between that formula in its simpler, but consequently only approximate, form, and the exact deve- lopment. In the present instance, in continuation of the same object of facilitating the study of this highly interesting por- tion of the science of light, my design is, besides some general remarks, to furnish certain constant elements which enter into all calculations by the exact method; together with one more instance of the comparison of this method with the approxi- mate one from the same source. The exact method, in fact, consists in this: The relation is expressed by the series of powers of the reciprocal of A re- sulting from the division of the development of the sine by the arc, with certain indeterminate coefficients. In the approxi- mate method these are supposed all constant and equal, and are expressed by a common factor. In the exact development this cannot be allowed; but an investigation is given by which they are, in fact, eliminated ; and there results a method for obtaining the theoretical index which is equivalent to the enunciation of a law expressing the connexion of the index of any one ray for a given medium, with three others supposed assumed: thus successively each of the four remaining of the seven standard rays have their indices found: or, in another point of view, we may say, that (taking three terms of the series) there are three constants to be found from observa- tions. ‘These depend on the medium; when we eliminate them therefore it is in effect equivalent to assuming three of the indices given by observation. The very name of an approximate method commonly con- veys the idea of a shorter and simpler process. In the pre- sent instance, however, the case is quite otherwise. On look- ing at the analysis contained in my former papers the exact method might appear long and intricate, but in fact the pro- cess of calculation is much simpler than might at first sight be imagined, and shorter than in the approximate method. The whole consists in the determination of the two constants log. Rete le Ye-_ Remarks on the Formula for the Dispersion of Light. 117 aand log. 6 for each ray, and the differences of the indices of the assumed rays, which constitute the other factors in the equation (26.), (Lond. § Edinb. Phil. Mag. for March 1836). That equation in a general form for finding the index of any ray », whose constants are a, and 6,; supposing the observed indices for B F and H assumed, is as follows: h;— hp = @, (Up = yp ) + By (ery — 2p, + Mp ) The following values of log. a, and log. 6, have been given in the foregoing paper, log a, = 1°80441 log b,, = 1°06281 I have also received the following from the same source, log a, = 1°74345 log b, = 1:63384 It is easy to determine values of the same constants for the other rays which remain to be found, viz. C and E. They are deduced by the formulas (analogous to those in the former paper, Eq. 15. 27. &c.), B 1 ae inet Ft oe [1 —2¢,] Beeson debtor t2e,l- By substituting the values of + from I'raunhofer’s observa- tions, we readily obtain, log a, = 1:95433 log b, = 2°65253 log a, = 1°49646 log b,, = 1:03196 With these logarithms, and those of the other factors in the above equation for », which are derived from the three indices Py Mp My assumed from observation for the particular me- dium, we thus get immediately the values of «, for the other rays resulting from the exact formula of theory. It would be easy to give examples of this method; but for the present I shall confine myself to stating the results ob- tained by it for the ray G in Fraunhofer’s media; compared, 118 Rev. Prof. Powell on the Formula as before, with the approximate results of my former compu- tation, performed by methods which will now be wholly su- perseded. Se ee eee Ke Ke Ke Medium, Observed by Calculated Calculated Fraunhofer. by the exact by the approxi- formula. mate formula. Flint-glass 13. 1°6602 1:66066 1°6609 Do. 23.| 1°6588 1°65910 1°6582 Do. $0.| 1°6554 1:65569 1°6551 Do. 3.| 1°6308 1°63101 1°6313 Crown-glass M., 1°5735 1°57368 | 1°5738 Do. 13.| 1°5399 1°54001 1°5399 Do. 9. | 1°5416 1°54182 15416 Oil of turpentine.| 1°4882 148833 1°4886 Solution ofpotash., 1°4126 1°41272 1°4126 Water. 1°3413 1°34140 1°3413 The preceding method enables us to calculate the indices for C, D, E and G, supposing those for B, F, and H assumed. It may, however, be desirable, for rendering the comparison of any case with theory complete and satisfactory, to possess the means of calculating likewise the indices for B, F, or H, assuming three others, or generally any index. For this pur- pose we must have recourse to the more general form (21.). This will not, in fact, be found more complex or difficult in practice, notwithstanding the simplification obtained by intro- ducing the particular relation subsisting between 7, +, and T,, on which the process above given depends. I shall therefore here add such a statement of the more general method as may be necessary for the object in view, and likewise furnish those constants which are independent of the particular medium, and necessary for the computation. The formula (21.) may be expressed, for brevity, thus: a (Hp —F x) k— (Hp—Fs) L+ (4u—Fp) mM, and the coefficients / 1 m which are independent of the me- dium are readily found from Fraunhofer’s values of 7, t,, T, Ty. From these values we have directly T= 15°489 7 2 iiss to? = 31°075 Ty = 46.666, and by means of these we obtain for the coefficients in (21-) the following values: Sor the Dispersion of Light. 119 log k = 3°87943 log 2 = 3°65263 log m = 3°94185. In any particular medium then, taking the logarithms of the differences of the three indices, we easily obtain the fourth by the above formula. For the corresponding relation of the other rays we must take « formula analogous to (21.), which will be as follows: ( (Hcp) (Ta 7B") (Fa —TB’) (Fa°—7’) 0 = { —(4e—Hp) (te°—73”) (FE°— 7B") (FE"— 76") + (He Hs) FE" tB°) (Fe° 7B") (TE Te”) which for brevity may be written as before, 0 = He Pp) HM — (Upp) 2 + (ua —Hp) mm. The coefficients x! i! m! may be found exactly as before from Fraunhofer’s values of T, TT, T, Which give to” = 17°045, te? = 26°437, ro? = 39-705. By means of these we obtain log &! = 3°54623 log = 2-93137 log m'= 228794. I will only add at present that I am now engaged in deter- mining by observation the indices for various media, especially those of a highly dispersive nature: and in the few attempts as yet made to verify the theory in these cases, (in which it is manifestly put to a more severe test than in any of the cases hitherto given,) I have found the method just explained by far the most preferable. The approximate method in any form appears to me at once more troublesome and less satis- factory. The values of the constants applicable to all media above given, may be useful to those who may engage in such calculations, or in verifying those already performed by other methods. Oxford, June 19th, 1836. [ 120 ] XXVIII. On certain Improvements in the Construction of Mag- neto-electrical Machines, and on the Use of Caoutchouc for Insulation in Voltaic Batteries. By Frep. W. Mutuins, Esq., M.P., F.S.S. To the Editors of the Philosophical Magazine and Journal. GENTLEMEN, I THINK it important to call the attention of the scientific readers of your valuable Journal, to some improvements recently made by me in the construction of the magneto-elec- tric machine, which go far to demonstrate the still very im- perfect state of these instruments, and form a foundation for alterations infinitely more important both in their mode of construction and application. The machine whose power I had an opportunity of testing was constructed on the most approved principle, and consists of two sets of bar-magnets arranged vertically, each set con- sisting of a dozen bars, and the upper poles of one set being unconnected with those of the other. I had previously seen and examined horizontal horse-shoe machines, and so far as I was enabled to institute a comparison considered the other mode of construction to be preferable. After trial, however, it struck me that the power of all magneto-electric machines was very imperfectly developed, and that it might be possible to obtain considerably greater effects from the same number of magnetic bars by establishing a magnetic connexion be- tween the poles of thelatter, and this without much difficulty or increased expense. With this view I procured two mag- netized arcs of the shape given in the an- _------~. nexed figure, and of the same width and = ~~. ‘ as thickness as the bars of the machine. I /_” Sa Lat then applied them, one to the opposite § N poles of the outséde pair of bars, and one to those of the znszde, and on giving the shock to a gentleman who was present, and who had tried the power of the instrument when the poles were unconnected, the effect was so much increased that he refused to repeat it, and on trying it on myself I found the power to be fully double what it had previously been. I was aware that connecting pieces of soft iron were sometimes used, but that their utility was said to be very questionable, and having myself tried them, I can safely say that soft iron as a mode of connexion is useless; it is evident, therefore, that the increase of power does noé depend upon connexion, wnless when the substance forming the connexion is in a peculiar state, and thereby capable of exerting a certain influence on the Mr. Mullins on an improved Magneto-electrical Machine. 121 poles of each set of magnets, which influence, it can be shown» does not depend upon the size of the connecting magnets, for I have tried large horse-shoe magnetic bars, single and in sets, without any increase of power beyond that obtained from the small magnetic arcs represented in the figure. Induction is certainly a cause, but not the sole cause of the increased power; there are other causes, as yet unexplained, which I trust may appear satisfactory to those who may per- use a paper which I am now preparing on this highly inter- esting subject: suffice it here to say, that in the future con- struction of the instruments in question, magnetic arcs in con- nexion with vertical bar-magnets should decidedly be used in preference to any other form or mode of construction at present known; and I would strongly advise any person who happens to have a machine of the horse-shoe form to cut off the bend as indicated in the annexed figure and reapply the same or other pieces of the same size mag- netized, for by so doing it will be found that a vast increase of power will be obtained. I have thrown out these hints in the hope that they may lead to still greater improvements in the mode of develop- ing the powers of combined magnets. In concluding this subject it may be well to observe that with my improved magnetic ma- chine I have charged a Leyden jar, and obtained by the same means various other results similar to those obtained from the action of the common electrical machine. In conclusion I would add, that in the various experiments I have made in regard to the best modes of developing and sustaining voltaic electricity, I have found that caoutchouc, or Indian-rubber, may be used with great advantage for insula- tion. I have applied it in place of glass in my intensity- sustaining battery; and as it can be made to adhere to the copper and may be laid on as thin as common letter-paper, a combination of plates or cylinders may be brought so close together as to occupy only a third of the space filled by a si- milar combination in the batteries at present used. In my intensity-battery, from the advantages derived from bringing the metallic cylinders as close as possible, this mode of insu- lation is most convenient and satisfactory. I am, Gentlemen, yours, &c. House of Commons, July 1, 1836. Frep. W. Motuins. Third Series. Vol. 9. No. 52. Aug. 1836. bs f 122 j i XXVIII. Letter from Mr. Fanapay to Mr. Brayley on some former Researches relative to the peculiar Voltaic Condition of Iron reobserved by Professor SCHOENBEIN, supplementary to a Letter to Mr. Phillips, zm the last Number. My pear Sir, Royal Institution, July 8, 1836. ] AM greatly your debtor for having pointed out to me Sir John F. W. Herschel’s paper on the action of nitric acid on iron in the Annales de Chimie et de Physique; 1 read it at the time of its publication, but it had totally escaped my me- mory, which is indeed a very bad one now. It renders one half of my letter (supplementary to Professor Schoenbein’s) in the last Number of the Philosophical Magazine, p. 57, super- . fluous; and I regret only that it did not happen to be recalled to my attention in time for me to rearrange my remarks, or at all events to add to them an account of Sir John Herschel’s results. However, I hope the Editors of the Phil. Mag. will allow my present Jetter a place in the next Number; and en- tertaining that hope I shall include in it a few references to former results bearing upon the extraordinary character of iron to which M. Schoenbein has revived the attention of men of science. ** Bergman relates that upon adding iron to a solution of silver in the nitrous acid no precipitation ensued *.” Keir, who examined this action in the year 1790+, made many excellent experiments upon it. He observed that the iron acquired a peculiar or altered state in the solution of sil- ver; that this state was only superficial; that when so altered it was inactive in nitric acid; and that when ordinary iron was put into strong nitric acid there was no action, but the metal assumed the altered state. Westlar, whose results I know only from the Annales des Mines for 1832 +, observed that iron or steel which had been plunged into a solution of nitrate of silver lost the power of precipitating copper from its solutions; and he attributes the effect to the assumption of a negative electric state by the part immersed, the other part of the iron having assumed the po- sitive state. Braconnot in 1833§ observed, that filings or even plates of iron in strong nitric acid are not at all affected at common temperatures, and scarcely even at the boiling-point. Sir John Herschel’s observations are in reality the first which refer these phenomena to electric forces; but Westlar’s, * Phil. Trans, 1790, p. 374. + Ibid., pp. 374, 379. t Annales des Mines, 1832, vol. ii. p.322; or Mag. de Pharm. 1830. § Annales de Chimie et de Physique, vol. li. p. 288. Mr. Faraday on the peculiar Voltaic Condition of Iron. 128 which do the same, were published before them. The results obtained by the former, extracted from a private journal dated August 1825, were first published in 1833*. He describes the action of nitric acid on iron; the altered state which the metal assumes; the superficial character of the change; the effect of the contact of other metals in bringing the iron back to its first state; the power of platina in assisting to bring on the altered or prepared state; and the habits of steel in nitric acid: he attributes the phenomena toa certain permanent elec- tric state of the surface of the metal. I should recommend the republication of this paper in the Philosophical Magazine. Professor Daniell, in his paper on Voltaic Combinations + (Feb. 1836), found that on associating iron with platina in a battery charged with nitro-sulphuric acid the iron would not act as the generating metal, and that when it was afterwards associated with zinc it acted more powerfully than platina it- self. He considers the effect as explicable upon the idea of a force of heterogeneous attraction existing between bodies, and is inclined to believe that association with the platina cleanses the surface of the iron, or possibly causes a difference in the mechanical structure developed in this particular position. In my letter, therefore, as published in the Philosophical Magazine for the present month (July), what relates to the preserving power of platina on iron ought to be struck out, as having been anticipated by Sir John Herschel, and also much of what relates to the action of silver and iron, as having been formerly recorded by Keir. The facts relating to gold and carbon in association with iron; the experimental results as to the electric currents produced; the argument respecting the chemical source of electricity in the voltaic pile; and my opinion of the cause of the phenomena as due to a relation of the superficial particles of the iron to oxygen, are what remain in the character of contributions to our knowledge of this very beautiful and important case of voltaic condition presented to us by the metal iron. I am, my dear Sir, yours very truly, EL. W. Brayley, Esq. M. Farapay. London Institution. * Annales de Chimie et de Physique, 1833, vol. liv. p. 87. + Phil. Trans. 1836, p. 114. Pg [ 124° ] XXIX. On the Carboniferous Series of the United States of North America. By Tuomas Weaver, Esq., F.R.S., F.G.S., M.R.LA., &c. §c.* AVING in the year 1834 passed through the United States of North America from the Gulf of Mexico to New York, the geology of those vast regions could not fail to arrest my attention. Up to the period of my visit, the geological relations of those States had not received much of my notice beyond what had been published at an earlier day by Mr. Maclure and some others. My mind was therefore the more open to unbiassed impressions. But on my return to En- gland I took great interest in comparing those impressions in particular with the great body of valuable information that has been contributed by different writers concerning the coal-bear- ing rocks of the United States, especially in Prof. Silliman’s. American Journal of Science, the Transactions of the Geolo- gical Society of Pennsylvania, the separate publications of our countrymen Messrs. G. W. Featherstonhaugh and R. C.Taylor, and the works of Professor Eaton. The general result, as de- rived from this comparison and combination, I have embodied in a condensed form in a note appended to my Memoir on the South of Ireland, there drawing a parallel between the rela- tions of the carboniferous series in the British Isles and the United States; but as some months may yet elapse before the publication of that Memoir in the Geological Transactions be effected, it has been suggested that it would be useful to make an earlier and somewhat more extended communication on the subject through the medium of a scientific journal of extensive circulation.+ * Communicated by the Author. + In collateral evidence of the correctness of my views, the following pa- pers on the carboniferous rocks of the United States are particularly deser- ving of the reader’s attention : In the American Journal of Science. Vol. 4. Mr. Z. Cist on the range of the anthracite formation in Pennsyl- vania, (1822, 6. Mr. James Pierce on the carboniferous rocks of the Catskill moun- tain chain. (1823.) 12. The same author on the anthracite, bituminous coal, salt and iron of Pennsylvania. (1827.) 18. Professor Silliman on the anthracite region of Lackawanna, and Wyoming on the Susquehanna. (1830.) Mr. David Thomas, Geological Facts. 19. Professor Silliman on the Mauch Chunk and other anthracite regions of Pennsylvania. (1831.) Professor Eaton on the coal formations of New York and Pennsyl- vania. 19, Mr. David Thomas, remarks on Professor Eaton’s observations on the coal formation in the State of New York. On the Carboniferous Series of North America. 125 . My route lay up the Mississippi and Ohio rivers to Pittsburg, and thence overland to Lake Erie, to Buffalo, Niagara, and partly by land and partly by water through the state of New York to the city of that name. In this course, from the first visible rocks of carboniferous limestone and its occasional as- sociates of shale and sandstone adjacent to the Mississippi and Ohio rivers, to the continuous coal measures which come in force near the influx of the great Kanawha into the latter river, extending thence westward into the state of Ohio, and northward through the Virginia, Pennsylvania and New York States to Lake Erie, I was very forcibly struck by the nearly Vol.23. Professor Eaton on the coal beds of Pennsylvania, as being equiva- lent to the great secondary coal measures of Europe. (1833.) He deprecates the application of the term transition either to the car- boniferous rocks of the Alleghany or Catskill mountains; and refers to his Geological Text-book, p. 91, second edition (1832) ; in which see hereon in particular pp. 66, 67, 79, 90, 110, 121,124, 125, as affording further evidence on the question. N.B. The relations of the carboniferous series have been much ob- scured by the peculiar terms employed by this author; the signi- fication of which, however, has been explained by Mr. G. W. Featherstonhaugh in a manner that quite accords with the con- struction I had myself put on what came under my own observation during the course of my travels. See vol. i. p. 92 of Proceedings of the Geological Society of London (1828), and Phil. Mag. and Annals, vol. v. pp. 138, 139. (1829.) ; [also vol, vi. p. 75, 76, and Lond. and Edinb. Phil. Mag. vol. vii. p. 515, note—Enrr.] 25. Ten days in Ohio by a naturalist. (1834.) 29. Dr. Hildreth on the bituminous coal deposits of the valley of the Ohio (1835.) This is a particularly valuable memoir for the de- tails it affords. Mr. G. W. Featherstonhaugh. Geological Report made to both Houses of Con- gress. (1835.) Mr. R. C. Taylor, on the north-eastern extremity of the Alleghany moun- tain range in Pennsylvania, in Loudon’s Magazine of Natural History. (Oct. 1835.) In the first volume of the Transactions of the Geological Society of Penn- sylvania. (1835-) Mr. R. C. Taylor on the relative position of the transition and se- condary coal formations in Pennsylvania. The same author on the coal basin of Blossburg on the Tioga river. Professor Proost, four papers on the organic remains of the carbo- niferous limestone of Tenessee, &c. Mr. E. Miller, Geological description and section of a portion of the Alleghany mountain west of Hollydaysburg. Dr. Harlan on the fossil vegetable remains in the bituminous coal measures of the Alleghany mountains referred to in Mr. E. Miller’s paper. Mr. ‘I. A. Conrad on some fossil shells presented by Mr. E. Miller from the Alleghany mountains. Mr. R. C. Taylor, Memoir of a section passing through the bitu- minous coal field near Richmond, in Virginia. 126 Mr. Weaver on the Carboniferous Series perfect horizontality of the strata throughout, the prevailing deviation from that position being a slight inclination to the: southward, subject however to gentle undulations upon a large scale. Valuable beds of bituminous coal occur low down in the car- boniferous limestone as well as in the higher accumulation of the common coal-bearing measures. Coal is thus obtained in the former adjacent to the Mississippi, near Memphis in Te- nessee, and bordering on the confluence of the Missouri with that river, and in Illinois; also near the Ohio river in the vi- cinage of Owenborough in Kentucky, and in Indiana opposite to Hawesville. In its western extent into Arkansas the carboniferous lime- stone appears to come in contact partly with a greywacké tract and partly with the old red sandstone. From the vicinage of the Great Kanawha river the conti- nuous coal-bearing measures extend to the south-west through Western Virginia and the eastern parts of Kentucky and Te- nessee into the northern parts of Alabama, and to the north- east, as above stated, through Pennsylvania into the State of New York. In the conterminous regions of Ohio, Pennsylvania, and Virginia, the continuous coal-bearing measures include not unfrequently intercalated beds of limestone, which often con- tain marine animal remains. Some of the coal measures are said also to exhibit in places fossil freshwater shells; and in this general series, beds of sandstone conglomerate are not of uncommon occurrence. In the State of New York the carboniferous limestone, which underlies these coal measures, reposes partly on old red sand- stone, partly on transition rocks. At the northern extremity the old red sandstone which lines the south coast of Lake Ontario from the west of the Niagara to the east of the Oswego river, distinctly underlies the limestone shale -and limestone from Queenstown, by the gorge, upward to within two hundred yards of the ferry below the Falls of Niagara, with a gentle dip throughout to the southward. ‘The same relative position is observable west of Lockport, in proceeding east from Lewis- town by the line of road that leads to Rochester, also in the Genesee river north of the latter town, and in the course of the Oswego river. To the east of the Oswego the old red sandstone reposes on transition rocks, and being deflected to the south-east, on approaching the Helderberg mountains it appears to be overlapped and concealed by the carboniferous limestone, the latter then coming in contact with the transition rocks on the east, which range from Canada to the southward : i ee of the United States of North America. 127 while still more south in Pennsylvania, the coal measures appear to overlap the carboniferous limestone on the east, and to come also in direct contact with the transition rocks. In tracing the order of succession from the carboniferous limestone to the superincumbent coal measures from north to south, the same low angle of inclination to the south is observable from Niagara in the direction of Buffalo, and thence along part of the south coast of lake Erie. The same disposition is like- wise to be remarked in passing south by the lakes of Cayuga, Seneca, &c., whose waters find a common vent on the north by the river Oswego. South of those lakes the land rises ra- pidly by an accumulation of coal measures, forming the nor- thern aspect of the Alleghany mountains, and the southerly dip being still observable. This series contains also red sand- stone and conglomerate and beds of limestone, and includes in the higher regions the abundant deposits of coal that occur in the northern confines of Pennsylvania, in the anthracitous coal field of Carbondale and Lackawanna and Wyoming on the Susquehanna, and the bituminous coal fields of Bradford, Tioga, Lycoming, and Clearfield. In the association of beds of limestone with the coal-bear- ing measures, we perceive an analogy to like phenomena in parts of the coal tracts of the North of England and of Scotland. In the immense extent of the carboniferous rocks of the United States, stretching on the one hand from the State of New York on the north-east to that of Alabama on the south- west, and again from that of New York on the east to that of Missouri on the west, the coal is generally bituminous; but great deposits of anthracitous coal occur in the north-eastern and eastern parts of Pennsylvania, in the field of Carbondale, Lackawanna and Wyoming, as above stated, and more south in portions of the regions traversed by the Lehigh and Schuyl- kill rivers. These anthracitous deposits have been referred by some geologists to the transition epoch; but from all that I have been able to learn of their general characters, position, fossil plants and other organic remains, I conceive them to belong to the great carboniferous order. Mr. Z. Cist of Wilkesbarre has shown that there is a continuity in the anthracitous coal formation, extending from a district lying north of Harrisbur through the regions bordering on the Schuylkill and Lehigh rivers to the valley of the Wyoming on the Susquehanna, and thence up the valley of Lackawanna in the direction of Car- bondale. From hence to the bituminous coal fields in Bradford and Tioga counties, situated more west, is a distance of only a few miles, and Professor Eaton conceives these formations to be connected, and to pass into each other as portions of the 128 Mr. Weaver on the Carboniferous Series same geological deposits; a view in which he is supported by these anthracitous and bituminous coal tracts containing fossil plants, similar to those occurring in the bituminous coal field near Zanesville in Ohio, and similar to such as are found also in the great coal fields of Europe, at Newcastle-on-Tyne, at Saarbruck, &c.: and the opinions expressed on this subject by Professor Silliman and Dr. Harlan appear to lean the same way. in further corroboration of this view it may be added, that both the anthracitous and bituminous coal regions in Pennsyl- vania are productive of large quantities of clay iron stone, the usual concomitant of the coal fields of the great carboniferous order. On the other hand, Mr. R. C. Taylor has taken a different view, and refers the anthracitous coal of Pennsylvania to the transition zra; but I confess the evidence which he has ad- duced does not appear to me to disprove the connexion in the north-eastern part of Pennsylvania between the bitu- minous coal fields of Lycoming, Tioga, and Bradford, with the anthracitous coal fields of Carbondale, Lackawanna and Wy- oming. More south, from the two sections which the author has given as roughly traced for the purpose of illustration, the one being drawn from Lycoming county and the other from Clearfield county, but both from the Alleghany mountain range on the north-west to the valley of the Susquehanna on the south-east, it would appear that a wide interval occurs between the nearly horizontal bituminous coal range of the Alleghany mountain on the west and the anthracitous coal range of Schuylkill, &c. on the east; an interval occupied by a series of rocks which, within the transverse distances of 76 and 66 miles respectively, exhibit two anticlinal lines, exposed, it would appear, by abruption, and which are referred by the author to the transition system. In the Lycoming section (No. 2 of the author) the beds and distances are given in the following order: Miles (a.) From the Alleghany mountain, composed of the coal formation supported by old red sandstone dipping west, and underlaid by shales, limestone, sandstone, to limestone in the Muncey valley (there in anticli- Halborden) ro2k ty Uae a RP Se ee Succeeded by (b.) Greywacké slate, limestone, greywacké shales, with two beds of limestone, greywacké, shales, to sand- stone in the valley of Penn’s Creek, (there in syn- clinal‘order}: sth Gh 0 REE ER a tee of the United States of North America. 129 Miles. Brought forward... 38 Succeeded by (c.) Shales, limestone, shales, limestone, to sandstone with conglomerate and a thin bed of bituminous caking coal (the accompanying shale of which con- tains splendid fossil plants) in St. Patrick’s. hill, (there in anticlinal order, adjoining the Susquehanna RUNS.) «sienna AAC ote eh senha eet unneanon ita abeniee meas LG Succeeded by (d.) Red shale across the Susquehanna valley to Blue SU LALSIING «sn comet SeeM picsapadndey Ease, of caste { wee] cee) 76 In the Clearfield section (No. 3 of the author) : (a.) From the Alleghany mountain, composed as in the Lycoming section and dipping west, underlaid by -greywacké shales, limestone, sandstone, to limestone in the Nuttany valley (there in anticlinal order) ... 10 Succeeded by (4.) Sandstone with conglomerate, limestone, sandstone and shales, limestone, conglomerate and sandstone, shales, limestone, to conglomerate and sandstone in Juniata valley (there in synclinal order) ... ... 25 Succeeded by (c.) Limestone and shales, grit, limestone to sandstone with conglomerate and a thin bed of bituminous caking coal, adjoining Susquehanna valley, (and there insntichmal order), ..4) 000 poses tees Soedklesiaagi®KS Succeeded by (d.) Red shales, sandstone, and conglomerate across the Susquehanna valley to Blue mountain ... ... ... 16 —— 66 In a third section (No. 1 of the author), still more south, namely, in the county of Bedford, and also drawn originally from the Alleghany bituminous range on the north-west in a south-east direction, but in the portion represented, commen- cing at Tussey mountain, passing thence over a country with an undulated surface to Allegripus mountain, the Raystown branch of the Juniata, Hopewell ridge, and still further east the dip is throughout, from Tussey mountain to the south-east, at angles varying from 30° to 80°. From T ussey mountain, composed of red sandstone and conglomerate, dipping east, to Third Series. Vol. 9. No. 52. Aug. 1836. Q 130° Mr. Weaver on the Carboniferous Series Hopewell ridge, occurs the following series of beds: limestone and limestone shale, variously coloured shales and argillaceous sandstones; sandstone and conglomerate in Allegripus ridge, including a bed of bituminous shale with impressions of ferns; red rock and shale in the Raystown branch of the Juniata; conglomerate, various sandstones, shales, and argillaceous beds containing coal beds in the Hopewell ridge and continued still further east. The coal beds thus first appearing in Hopewell ridge, (of which the most western is 20 miles east of the Alle- ghany mountain,) appear to be of a highly bituminous quality, caking in the fire and forming excellent coke, but of high spe- cific gravity, 1°700, and denominated by the ‘author transition bituminous anthracite. It is to be observed also, that the shale which alternates with the coal measures here is rich in clay ironstone. On this section I shall merely take the liberty to remark, that were we to conceive disruption and denudation to have taken place between the Alleghany bituminous moun- tain range on the west and the Hopewell ridge on the east, with an original curvature of the beds from west to east; or even to suppose these eastern and western coal tracts to have been originally separate deposits, there appears no very conclu- sive reason, judging by the evidence given, why the coal of the Hopewell ridge might not be referred to the carboniferous se- ries, as indeed it had been previously in the judgement of the committee of the Senate of Pennsylvania. In these sections the author represents the eastern base of the Allezhany mountain range as consisting of old red sand- stone, with subordinate beds of limestone supporting the coal measures; and the same language is employed when speaking of the north-eastern extremity of the Alleghany mountain range in Pennsylvania; and again when describing the coal basin of Blossburg on the Tioga river; on which it is remarked, ‘‘a large portion of these red sandstones and the lower red argillaceous sandstones and shales are crowded. with Producte and crinoidal remains; and occasionally Fucoides and Caryo- phyllicze, Pectens and Spiriferz are interspersed.” The applica- tion of the term old red sandstone does not seem quite correct in these cases, in as much as these beds appear to be an alter- nating series lying above the great body of the carboniferous limestone that becomes apparent in the northern parts of the State of New York, and which itself reposes there conformably on the extensive formation of old red sandstone subjacent to it, while it supports in a similar manner the alternating beds in question, and these support the more productive coal- bearing measures. In this distribution of the coal in Pennsylvania, anthracitous of the United States of North America. 131 on the east and bituminous on the west, we may observe an analogy to the coal deposits in South Wales, where the eastern portions are bituminous and the western anthracitous; and again with those in Ireland, where the northern deposits are bituminous and the southern anthracitous. But both the Welsh and the Irish coal fields belong to the great carboni- ferous order, and I anticipate that such also will be admitted to be the case with respect to the Pennsylvanian, which point indeed, in reference to the north-eastern parts of that state, ap- pears to me fully established by Professor Eaton, The mere quality of coal, as being anthracitous, cannot alone be consi- dered a decisive criterion of its antiquity, though so conceived by some geologists. In the extensive tracts of Pennsylvania alone, it must neces- sarily take time fully to develop all its mineral relations, par- ticularly in districts that may prove of an intricate nature. From the labours of Mr. R. C. Taylor, specially devoted to these researches, we may expect very valuable information, not only in respect of the rocks of the great carboniferous order, but of those of the transition system: and it will be a subject of bigh interest to have it shown to what extent the rocks of the latter epoch in the United States may correspond with the Silurian or Cambrian divisions of the series so ably developed by the assiduous labours of Mr. Murchison and Professor Sedgwick in England and Wales, or with the trans- ition rocks of Somerset and Devon under the investigation of Mr. De la Beche, or with those of Ireland, which I have en- deavoured to describe. In such a comparison it is probable that more than one parallel may be drawn, after a careful ex- amination of the transition tracts of the United States. As it does not enter into my present view to consider the slight layers of anthracite that are met with in transition clay slate on the river Hudson, or the thicker beds ascribed to that zera that occur in New England, I would refer for detailed information on this subject in particular to the very valuable work of Professor Hitchcock on the Geology of the State of Massachusetts. I shall conclude with the general remark that if the land of the United States be rich in the vegetable productions of the warm and temperate zones of the earth, it is no less so in the abundance and variety of its mineral stores, of which the prin- cipal are its inexhaustible deposits of coal and iron, which may be considered as the mainsprings of arts and manufactures, In the possession of such treasures, combined with the active spirit engendered by free PONT and the natural and 2 132. Mr. Sturgeon on Electro-pulsations and Electro-momentum gradually improving facilities of internal and external commu- nication, our American brethren may look forward to the at-: tainment of a state of greatness and prosperity that may not readily lie within the compass of human calculation. XXX. On Electro-pulsations and Electro-momentum. By Wituam Srurceon, Lecturer on Experimental Philosophy at the Honourable East India Company’s Military Academy, Addiscombe, &c.* ie is very well known to the readers of the Philosophical Magazine, that I have long considered electric currents; when transmitted through inferior conductors between the poles of a voltaic battery, as the effect of a series of distinct discharges, in such rapid succession as not to be individually distinguished by the senses. Such currents I have called electro-pulsatory. See my theory of magnetic electricity in the London and Edinburgh Philosophical Magazine, vol. ii. p- 202. By following up these views of electro-pulsations, I was about two years ago enabled to dispense with all acid or sa- line liquids, in the employment of galvanic batteries, for the purpose of galvanizing, as it is called, either to satisfy the cu- riosity or as a medical process; and my plan, which answers very well, I have found to be productive of a considerable saving in the expense necessarily attendant on the use of voltaic batteries when excited by acid solutions. It is well known that a Cruickshank battery of about a hun- dred pairs will, by employing water alone in the cells, charge to a certain degree of intensity almost any extent of coated surface of glass that we please; and that the same degree of charge is given to it by a single contact of the conductors, however short its duration. ‘This being understood, and un- derstanding also that the shock produced by any discharge from a given intensity would be proportional to the quantity of fluid transmitted in a given time, it was easy to foresee that a series of shocks in rapid succession might be produced by some mechanical contrivance, and that the degree of force might be regulated by varying the extent of coated surface. My first experiments were made with a hundred and fifty pairs of three-inch plates, and about seven feet on each side of coated glass; and my apparatus for producing a rapid suc- cession of shocks was one of Mr. Barlow’s stellated electro- * Communicated by the Author. Mr. Sturgeon on Electro-pulsations and Electro-momentum. 133 magnetic wheels* which was soldered to an iron spindle and put into rotatory motion by a wheel and band; the points of the wheel touching in succession a copper spring in connexion with the positive surface, and thus producing a discharge at every contact of the wheel and copper spring. When the two surfaces are connected by wires with two basins of salt water, and the hands immersed one in each basin, the effect experienced is precisely that of the discharge of a voltaic battery. The discharges can be made in such rapid succession as to prevent the sensation of distinct shocks ; and if the process were to be concealed it would require some experience to distinguish between the effects on the animal ceconomy from this apparatus and those from a voltaic bat- tery charged with acid and water. My views being so far verified, the next attempt was to simplify the apparatus and make it more portable; and as it was readily seen that if one hundred pairs would charge glass of considerable thickness, thinner glass might be charged by fewer pairs; this was done; and eventually the glass entirely dismissed, and its place supplied with well-varnished Bristol- board. ‘These boards answer exceedingly well as a reservoir for low intensities; they may be coated to within an inch of the edge all round, and placed upon their edges either on a piece of glass or on a board properly prepared, and arranged to any required extent like the plates of a voltaic battery, but when considerable intensity is wanted, it is better to use thin glass. From these facts we learn that metallic surfaces of many acres of extent may possibly be charged to a low intensity in the interior of the earth, by having a thin intervening stratum of inferior conducting matter sufficient to insulate from each other their dissimilar electric surfaces. It may now be understood that the slightest accident which would suddenly break through the insulation, such as the sinking of a mass of metalline matter from one stratum to the other, would cause a sudden rush of an immense ocean of the electric fluid, which might be productive of subterranean light- enings and tremendous explosions sufficient to shake an exten- sive range of country on every side. Connected with the preceding facts there are others which may be conveniently mentioned in this place, and which would lead us to similar explanations of the causes of subterraneous, convulsions. Electric currents of considerable magnitude when suddenly checked, or diverted to a new channel, produce a * [See Phil, Mag., First Series, vol, lix. p. 241.—En1r.] 134 Mr. Sturgeon on Electro-pulsations and Electro-momentum. momentum not very generally understood ; but which I will endeavour to explain. A coil of copper wire excited by mag- netic action will become a channel for an electric current; and whilst the whole circuit is metallic, the velocity of that current would be considerably greater than if any, even a small part of the circuit were of worse conducting materials : and if the current were suddenly transferred from a channel of the former character to one of the latter, by any contrivance whatever, it would meet a resistance on entering the new channel, which the momentum it had previously required would have to overcome; and a sudden disturbance of the elec- tric fluid, previously at rest, would take place, and a violent rush of the current would as suddenly follow. It is in this manner that shocks and sparks are produced by magnetic electric machines, where the current, previously in rapid motion, is suddenly transferred to a new channel of inferior conducting character; and all the fluid in the revolv- ing coil rushes through a person properly situated for the new route, and who experiences the electric shock, or else through a thin stratum of air at an interruption in the metallic circuit where the spark is produced. These, then, are some of the effects of electric currents, or of the momentum of the electric fluid in a state of motion, after the exciting cause is entirely cut off. The shock thus pro- duced may very conveniently be compared to the blow given by Montgolfier’s hydraulic ram. Electro-momenta may be produced by any mode of excitation whatever, and the effects will be proportional to the velocity and quantity of the electric fluid first put into motion; and the length of the original channel is also to be taken into account. If then electro- momenta, capable of producing violent shocks and vivid sparks, can be produced by a few hundreds of feet of thin copper wire, what is it that might not be expected from the electro-momenta of nature, arising from currents of many miles in extent, kept in motion either by heat, saline solutions, or by other causes, amongst the metalline strata below the surface of the earth? A sudden disruption in the circuit would insure the blow, and an earthquake might be the re- sult. Artillery Place, Woolwich, July 4, 1836. [..1385. J XXXI. Reviews, and Notices respecting New Books. A Practical Treatise on Locomotive Engines upon Railways; with Practical Tables, giving at once the Results of the Formule , founded upon a great many new experiments, &c. By the Chev. F. M. G. De Pambour. he is only within the last fewyears that the attention of engineers has been particularly directed to the mechanical capabilities of loco- motive engines; and their inquiries have, for the most part, been limited to the vague practical information that is commonly inferred from actual experiments. The vast and splendid projects that now occupy such an important position in the public mind, and that pro- mise such extensive and permanent advantages to society, have created a stronger and more lively interest in the science of railways. An engineer is expected to be, at least, practically acquainted with the theory of locomotive engines; he is supposed to possess that in- timacy with the laws of their physical and mechanical action, as to be prepared to estimate pretty nearly, on scientific principles, the speed with which any proposed engine will draw a-given load. How far this has really been the case is a question on which it will not here be necessary to offer an opinion ; but we may state, that in the first stages of this, as well as of almost every useful branch of science, the practitioner is obliged at first to glean his information from expe- riencealone. The construction of each successive engine suggests new and valuable information as to defects that may in future be avoided and improvements that may be adopted. ‘The working of each engine also furnishes the means of roughly estimating what may be done by any other of a similar construction. Afterwards, how~ ever, when the subject becomes to be scientifically discussed, me- thods are presented by which the capabilities of any intended engine may be previously submitted to an accurate calculation, whatever may be the plan of its construction, We do not think that this object has yet been fully accomplished. The author of the present work, however, treats the subject in a manner that shows him to be well acquainted with the mechanical theory. He first gives a very intelligible description of the locomotive engines employed on the Liverpool and Manchester railway, as well as. an account of their dimensions and proportions. He founds the calculations throughout the volume, on a great number of experiments that he has made himself with these engines. In the second chapter he gives rather a tedious discussion relating to the calculations of the true pressure of the steam from the indications of the lever and valve of the boiler: this might be abridged with advantage. The fourth and fifth chapters, which treat on the resistance along the railway and the proportions and effects, form the principal feature of the volume, and they contain a remarkably clear and comprehensive discussion of these most important points. The author very properly considers the friction of the engine separately from that of the load, and shows that in consequence of the additional strain on the machinery, it in- 136 Zoological Society. creases as the load increases. He also shows, that the rate of tra- velling with a given load does not depend solely on the tractive power of the engine, but that another important element enters into the calculation, viz. the evaporating power of the boiler. An ap- pendix contains a detailed account of expenses, profits, and other valuable particulars of a mercantile and speculative nature, drawn from the documents of the Liverpool and Darlington railways. Alto- gether, the work is written in a clear and unaffected style; the sub- jects throughout are treated very philosophically, and with great ability; the typographical execution is also exceedingly creditable, and, judging from the gratification we have experienced on its per- usal,we can have no hesitation in pronouncing it an elegant and truly valuable publication, that should be possessed by all persons inte- rested in such pursuits. XXXII. Proceedings of Learned Societies. ZOOLOGICAL SOCIETY. Dec. 22, PECIMENS were exhibited of numerous Shells of the 1836. — 2 genus Mitra, Lam., and of one species of Coneliz, Swains., forming part of the collection of Mr. Cuming; and an ac- count of them by Mr. Broderip was read, commencing as follows: «« The species of the genus Mitra, Lam., which I am about to de- scribe had been sent by Mr. Cuming, in whose cabinet they are, to Mr. Swainson, whose intimate acquaintance with this family renders him so particularly competent to the task of describing them. They ‘were named by him, and he also made notes respecting them before returning them. In the following account of them I have retained Mr. Swainson’s name in every instance but one: and whenever he has made any written observations I have quoted them. Characters, habitats, &c. of the following species were then given, and are printed in the ‘“ Proceedings.” Genus Mirra (Lam. and Swains.). Mitra nebulosa (representing nubila, Type 5,1, Sw.), Swainsonii (Type 1, 1.), Ancillides (5, (2 ?)), maura (representing Tiara foraminata, Type 1, 4.), fulvescens (5, 1.), testacea (5, 1. representing fulva), fulva var. (1, 2. representing Tiara), chrysostoma (5, 1. representing ferruginea), tristis (2, 4.), and effusa (1, 5.). Genus Tiara, Swains. (Mirra,Lam.) Tara foraminata (repre- senting Mitra maura, Type 2, 4.), muricata, mucronata, catenata (1, 3.), multicostata, rosea (1, 2.), millecostata (the close-set longi- tudinal ribs and cancellated base give this shell, which may not have attained its full growth, the aspect of a Cancellaria), lineata (5, 1), nivea (5, 3.), aurantia, terebralis, crenata (5, 3. or 3, 3.), rubra (1, 2.), semiplicata, and attenuata (5, 1). Mr. Swainson had written on the paper containing Tiara tere- bralis, ‘Type 4, 4. This is one of the most extraordinary shells in the collection, as it so closely resembles the Mitra Terebralis that, Xoological Society. 137 but for its possessing the generic characters of Tiara, it might pass -for the same species.” It is one of the most slender of its genus, and has very much of the general character and form of a Terebra; and its resemblance to Terebra is increased by the circumstance of its having one spiral groove, more deeply impressed than the others, placed at about one third of the length of each volution before the suture. The points of contact of the decussating with the longitudinal grooves are deeply impressed. There is a fine specimen in Mr. Broderip’s collection. Mr. Sowerby has furnished me with the account of this species. Genus Conor.ix (Swains.). Conoelix Virgo (representing Conus Virgo). The following observations by Mr. Swainson elucidate his notes in relation to the Mitres, appended to most of the characters of the shells above named :— *« To render my explanation of the notes and references attached to the different species of the Mitrane more intelligible to conchologists, it will be necessary for me to state, in as few words as possible, the result of my investigation of this subfamily, and the principles which have regulated these numerical indications. “« I have already, in another work, characterized the family Volu- tide, which appears to be that primary division of the Carnivorous Gasteropoda (Zoophaga, Lam.), which represents the Rasorial type among Birds, the Ungulata among Quadrupeds, and the Thysanura among perfect Insects (Ptilota): these analogies being of course remote, although founded on the structure of the animal, no less than on its testaceous covering. It thus follows that the Lamarck- ‘ian Mitre, instead of a genus, constitute a subfamily, which appears to be the subtypical group of the circle. he five genera composing this circle I have long ago characterized; and here, for some years, my analysis of the group terminated. The inspection, however, of the numerous species brought home by Mr. Cuming, and the gradually augmented number in my own cabinet, seemed to invite a still further and more minute investigation, for the purpose of ascertaining if any, and what, subgenera were contained in the more crowded groups of Mitra and Tiara. ‘This investigation was carried on, at intervals, for nearly twelve months; and the result sur- passed my most sanguine expectations. It has convinced me that not only does each of the genera of the Mitrane represent analogically the corresponding groups of the Volutine, but that the same rela- tions can be demonstrated between the minor divisions of the genera Tiara and those of Mitra: in other words, that these latter represent all the subfamilies and genera of the other Volutide, while they pre- serve their own peculiar or generic character. What I have just said on the parallel relations of analogy between the Mitrane and the Volutide, is strictly applicable, in fact, to the genera Mitra and Tiara, the primary divisions of each of which can thus be deemon strated subgenera. Nor is this all: the materials I have been for so many years collecting have enabled me to ascertain, in very many 138 Soological Society. instances, that the variation of the species, in each of these sub- genera, is regulated on precisely the same principle. Hence it fol- lows that the two circles of Mitra and Tiara, like the two divisions of Mr. MacLeay’s Petalocera, contain species representing each other, so that if their generic character is not attended to, it is almost impossible to discriminate them even as species. Many in- stances of this extraordinary analogy might be mentioned, indepen- dent of that here alluded to, between Mitra Terebralis and Tiara Terebralis. :, *« Selecting this shell to illustrate the numbers ‘“ Type 4, 4,” I may observe, that ‘Type 4’ signifies that it belongs to the fourth subgenus of Tiara, in which group it is the fourth subtype, uniting to Mitra maura, which is the fourth subtype of the first or typical subgenus. Mitra maura, again, as representing this latter shell, consequently becomes the fourth subtype of the first or typical sub- genus, and is therefore marked ‘‘ Type 1, 4.” The first figure always denotes the subgenus, and the last the station which the species ap- pears to hold in its own subgenus. «IT am unacquainted with any group in the animal kingdom which demonstrates more fully than this does the law of represen- tation. It may be mentioned, also, that nearly all the divisions I had long ago characterized, from the formation of the shells alone, have more recently been confirmed by a knowledge of their respec- tive animals: a knowledge for which we are entirely indebted to the able naturalists who accompanied the French expedition on board the Astrolabe.”—W. 8. Specimens were exhibited of several hitherto undescribed Cowries, most of which have been brought to England within the last few years. They were accompanied by characters and descriptions by J.S. Gaskoin, Esq., which are given in the “ Proceedings” under the following names, viz. Cyprea formosa (Capeof Good Hope), rubinicolor, producta, candi- dula (Mexico, Cyp. approximans, Beck, Cyp. olorina Duclos, but first described by Mr. Gaskoin), acutidentata (Isle of Muerte, Bay of Guayaquil), Pediculus, var. labiosa, vesicularis (Cape of Good Hope), and Becki. There was read an ‘“ Extrait du Quatriéme Rapport Annuel sur les Travaux de la Société d’Histoire Naturelle de Ie Maurice : par M. Julien Desjardins.” The communications relative to the Mammalia read before the Na- tural History Society of the Mauritius in the fourth year of its ex- istence have comprised an account by the secretary, M. Julien Desjardins, of a Whale which he regards as the Physeter macroce- phalus, Linn., that was cast ashore on an adjoining reef: and some observations by the same author on several of the Mammalia of the island, and particularly on the hybernation of the Tenrec, Centenes spinosus, Ill.; the lethargy of which animal takes place when the thermometer is not lower than 20° Cent., and even when it marks 26°. In ornithology M. Desjardins has also been the only contributor. He has described, as new, two Birds belonging to the island, and has wh Zoological Society. 139 proposed for them the names of Charadrius Nesogallicus and Scolo- pax elegans. M. Liénard, the elder, has, in the course of the year, described many Fishes, including a new species of Plectropoma, allied to the Plectr. melanoleuca, Cuv. & Val., which is of a uniform brown co- lour, with all its fins of a still deeper brown, except the pectoral which are orange; on this latter character his specific name is founded : a Holacanthus, La Cép., from Batavia, remarkable on ac- count of the numerous sinuous silvery lines which occupy principally the middle of the body; and having also on its face two yellow and two black bands, one of which is ocular: a Cheilinus, Cuv.: an Echeneis, Linn., furnished, on its suctorial disc, with twenty-five pairs of plates: and a Murena, Thunb., the body of which is of an ebony black, and the dorsal fin yellow; the trivial name being in- dicative of the latter peculiarity. He has also given some account of a collection of Fishes obtamed from the western coast of Madagas- car, and comprising thirteen species, several of which he regards as new. M. Desjardins hasdescribed as the blue-faced Tetrodon, a species remarkable for two large blue spots on each side of its face, and having the fm-rays as follows; D. 15. A.12. P. 14. C. 14.; it in- habits the seas adjacent to the Isle of France. In entomology the only communication made to the Mauritius Society was by M. Goudot, and related to the Insect described by Mr. Bennett at the Meeting of the Zoological Society on January 22, 1833, (Proceedings, Part i.p.12; Lond. and Edinb. Phil. Mag.,vol. ii. p- 478,) under the name of Aphrophora Goudoti. The commu- nication made to the Zoological Society, of which a full abstract is given at the page quoted, was apparently identical with that read before the Mauritius Society. The remaining zoological communication related to the Intestinal Worms, and was made by the Secretary. It gave some account of the Distoma hepaticum, Cuv., as found in the stomach of a cow; and of the Cysticercus Cellulose, Brems., existing in innumerable quan- tities over almost the whole of the head, trunk, and extremities of a sow. An “ Extrait du Cinquiéme Rapport Annuel” of the same Society, by M. Julien Desjardins, Corr. Memb. Z.S8., was also read. In the year of which the present Report gives an account, M. Desjardins has communicated to the Natural History Society of the Mauritius, a list of several species of Birds that are occasional visi- tors of that island; and has also referred particularly to the Coturnix Sinensis, Cuv., and the Nectarinia Borbonica, Il., as stationary in the Mauritius. M. E. Liénard has brought from the Seychelles a species of Gecko of considerable size; which he has described in a communication made to the Society: and M.E. Liénard has placed on record the existence in the adjacent seas of the Sphargis coriaceus, Merr. M. Liénard, the elder, has again made numerous contributions to ichthyology. He has given a detailed description of the Squalus Vulpes, Linn.: has described as new a T'richiurus, Linn., which ke 140 Xoological Society. had formerly regarded as the Trich. lepturus, Ej., but which has the eye much larger, more numerous strie on the suboperculum, and afew more rays in the dorsal fin: and has also described two species of Crenilabrus, Cuv., which he regards as new; one of them has three longitudinal rose-coloured bands on the white ground of the body, others on the dorsal fin, a large blood-red spot on the ventral fins, and D. 12410. A. 3+11; the other is banded like the pre- ceding, but is deeply rose-coloured on the back and pale yellow be- low, has a black circle surrounding the base of the pectoral fin, a large red spot above the anus, the dorsal and caudal fins red, the anal and yentrals yellow, the pectorals rose-coloured, and D. 12+9. A.3+11. He has also given a description of a Murena, Thunb., of a very pale olive yellow towards the front and brown towards the tail, and marked on the back by white ocellated spots bordered with brown. In the same department M.E. Liénard has contributed descrip- _ tions, from recent specimens, of several Serrani described by Cuvier and M.Valenciennes in their ‘ Histoire Naturelle des Poissons’ ; and has also given a description of a Blennius, Linn., destitute of appen- dages on the head. These fishes were observed in a voyage to the Seychelle Islands, whence M. E. Liénard brought back with him to the Mauritius a Chetodon of very varied colours, which M. A. Liénard subsequently described under the name of Chetodon diversicolor. M. Desjardins has stated, in a note, that the Mango fish, Polynemus longifilis, Cuv. & Val., is not found, as had been announced, in the Isle of France. And he adds that he has prepared an alphabetical index to the nine volumes of the ‘ Histoire Naturelle des Poissons’ that had then reached the Mauritius. M.Magon has presented to the Museum of the Society a fragment of a ship’s coppered keel pierced by the point of the upper jaw of a Histiophorus, Cuv., which still remains infixed in it. M. Desjardins has contributed the only notices relative to the Mol- Zusca, which have consisted of short descriptions of three species be- longing to the island: an Octopus, Oct. arenarius, Desj., found in the shell of a Dolium; a Pupa, of a red and yellow colour; anda small species of Helicina. He has also ascertained the existence at the Mauritius of the Tornatella flammea, Auct. To the same active member the Mauritius Natural History Society is indebted for the only entomological communication made to it in the fifth year of its existence: it is a detailed description of a large species of Julus brought from the Seychelles, and characterized as the Julus Seychellarum, Des}. Specimens were exhibited of various Fishes, forming part of a col- lection from Mauritius, presented to the Society by M. Julien Des- Jardins, and forwarded by him at the same time with the “‘ Rapports de la Société d’Histoire Naturelle de l’Ile Maurice.” These were severally brought under the notice of the Meeting by Mr. Bennett, who called particular attention to the following, which he regarded as hitherto undescribed, and of which the characters are given in the ‘‘ Proceedings,” viz. Roological Society. 141 Apocon teniopterus ; Acantuurus Desjardinii, Ruppelii, and Blo- chit; Lasrus spilonotus; and Anampsss lineolatus. Jan. 12, 1886.—A note addressed to the Secretary by Sir Robert Heron, Bart. M.P., was read. It referred to the writer’s success in the breeding of Curassows in the last summer at Stubton. From two individuals in his possession, the male of which is en- tirely black, and the female of the mottled reddish brown colour which is regarded as characteristic of the Crar rubra, Linn., Sir R. Heron has hatched in the last year six young ones in three broods of two eggs each: the eggs were placed under turkeys and common hens. Respecting one of them no notes were made; but the other five were all of the red colour of the female parent. Two of these, which were at two or three weeks old very strong, being still in the flower-garden, were killed in the night by a rat that had eaten its way into the coop in which they were. Two others were sent to the Earl of Derby, who wanted hens. The remaining one is now nearly, if not quite, full grown; and Sir R. Heron proposes to place it with the old pair. «« There is one great peculiarity,” Sir R. Heron remarks, “ attend- ing the old pair. Their principal food is Indian corn and greens, both which they eat in common: but whenever any biscuit is given to them, as an occasional treat when visitors are here, the male breaks it and takes it in his mouth; waiting, however long, until the hen takes it out of his bill; which she does without the slightest mark of civility, although on excellent terms with him. This proceeding is invariable.” Mr. Yarrell, on behalf of T. C. Heysham, Esq., of Carlisle, ex- hibited the egg, the young bird of a week old, one of a month old, and the adult female of the Dottrell, Charadrius Morinellus, Linn., obtained on Skiddaw in the summer of 1835. Several pairs were breeding in the same locality. He also stated that a specimen of the grey Snipe, Macroramphus griseus, Leach, a young bird of the year, has been obtained near Carlisle in the past year. This is the third recorded instance of the occurrence of the species in England. Some notes by Mr. Martin of a dissection of a Vulpine Opossum, Phalangista Vulpina, Cuv., were read, and are given in the “ Pro- ceedings.” A notice by Dr. Riippell, For. Memb. Z. S., of the existence of canine teeth in an Abyssinian Antelope, Antilope montana, Riipp., was read. It was accompanied by drawings of the structure de- scribed in it, which were exhibited. The following is a translation of Dr. Riippell’s communication. In several Mammalia of the order Ruminantia the adult males, and even some females, possess canine teeth, which are more or less de- veloped; to these teeth no other use has been attributed than that of a weapon of defence. ‘The Camels (Camelus), the Musk Deer (Moschus), and the Muntjak of India (Cervus Muntjak), possess these canine teeth in both sexes. In the red Deer (Cervus Elaphus) and in the rein Deer (Cerv. Tarandus), the adult males alone are provided with them, 142 Zoological Society. IT have just ascertained that there is a species of Antelope which possesses these canine teeth; but in which, by a singular anomaly, it is only the young males that are furnished with them. In these too they can only be considered in the light of half-developed germs; for the cartilaginous part which covers the palate and the upper jaw entirely conceals them. It is the Ant. montana, which I discovered in 1824 in the neigh- bourhood of Sennaar, and of which I published in my ‘ Zoological Atlas’ the figure of an adult male, that is provided, in its youth, with these anomalous canine teeth: the adults of both sexes, and the young females, are destitute of them. I observed, in my last journey in Abyssinia, many individuals of this species in the valleys in the neighbourhood of Gondar: it is far from rare in that locality, but the jungles mingled with thorns, which are its favourite retreat, ren- der the chase of it extremely difficult. At the time of the publication of my description of this new spe- cies, in 1826, I was possessed of only a single adult male, and there were consequently many deficiencies in my account of it. I am now enabled to add to this notice that the females of this species are always destitute of horns; that both sexes have, in the [groins] two rather deep pits covered by a stiff bundle of white hairs; and finally that the species lives in pairs in the valleys of the western part of Abyssinia, where it takes the place of Ant. Saltiana, an animal which it exceeds in size by nearly one half. These two species are called by the natives Madoqua, by which name the Abyssinians also designate the Ant. Grimmia, which equally constitutes a part of the game of that country, so rich in different forms of the Ruminant order.—E. R. A note by Mr. Martin was subsequently read, in which it was stated that it had once occurred to him to observe a rudimentary canine tooth in the female of a species of Deer from South America, the body of which had been sent to the Society’s house by Sir P. Grey Egerton, for examination. Having noticed an enlargement of the gum of the upper jaw, in the situation in which a canine tooth might possibly be supposed to exist, he cut into it, and found the germ of a canine tooth, about 3 lines in length, imbedded in the gum, and destitute of fang. Jan. 26.—Specimens were exhibited of numerous Birds, chiefly from the Society’s collection; and Mr. Gould, at the request of the Chairman, directed the attention of the Meeting to those among them which he regarded as principally interesting either on account of their novelty or for the peculiarity of their form. They included the following species of the genus Edolius, Cuv., which were compared with numerous others placed upon the table for that purpose. Envouivs grandis, Rangoonensis, Crishna, and viridescens. Of Edolius Crishna a very curious character is furnished by the long, hair-like, black filaments which spring from the head and mea- sure nearly 4 inches in length. The remaining previously undescribed Birds that were exhibited were characterized by Mr. Gould as Orpuxvs modulator, Ixos leu-. EEE a Zoological Society. 143. cotis, Coutunicincta fusca, Tricnornorvs flaveolus, and GrocicHLa Rubecula. Mr. Gould subsequently directed the attention of the Meeting to a specimen of the Twrdus macrourus of Dr. Latham, with the view of explaining the characters which induced him to regard that bird as constituting the type of a new Genus Krrracincra. Rostrum caput longitudine zquans, ad apicem emarginatum, rec- tiusculum, compressiusculum. Nares basales, plumis brevibus utplurimum tecte. Ale mediocres, rotundate: remige 1ma brevissima, 4ta 5taque subeequalibus, longioribus. Cauda elongata, gradata. Tarsi digitique longiusculi, tenues. Oss. Maribus color supra utplurimum niger; subtis brunneus vel albus. A paper by B. H. Hodgson, Esq., Corr. Memb. Z.S., on some of the Scolopacide of Nipal, was read; the copy transmitted by that gentleman to the Society containing various corrections of his me- moir which was published at Calcutta in the ‘Gleanings of Science’ for August, 1831. Mr. Hodgson’s object in the present paper is to bring under the notice of zoologists the various species of the family referred to which occur in Nip4l, on the natural history of which country he has, during a residence of several years, been engaged in making most extensive researches. ‘The result of these it is his intention immediately to publish, accompanied by finished representations of the animals, taken from drawings made in almost every instance from numerous living individuals of the several races. Mr. Hodgson first describes in detail the common Woodcock, Sco- lopax Rusticola, Linn., as it oceurs in Nipal; where it is, in every respect of form and colour, evidently identical with the European bird. In Nipal also it seems to be, as it is in Western Europe, of migratory habits: and the periods of its arrival in, and departure from, Nipdl, correspond altogether with the seasons of its appearance and disappearance in England. He then proceeds to describe in detail the several kinds of Snipe which occur in Nipal. Two of these are so nearly related to the common Snipe of Europe, Gallinago media, Ray, that Mr. Hodgson is induced to regard them as being probably specifically identical with that bird: and he ac- cordingly refers them to it as varieties, which are constantly distin- uished from each other by the structure of the tail. In one of them the tail-feathers are fourteen or sixteen in number, and are all of the same form: in the other the tail-feathers vary in number from twenty-two to twenty-eight; and the outer ones on either side, to the number of six, eight, or ten, differ remarkably from those of the middle, being narrow, hard, and acuminated. The latter bird may, however, be regarded as the representative of a species to which the name of Gall. heterura may be given. 144 Zoological Society. The other two Snipes of Nipal are unquestionably distinct from those of Europe. They are described as the solitary Snipe, Gall. so- litaria, Hodgs., and the wood Snipe, Gall. nemoricola, Ej. In the solitary Snipe the wings are remarkably long; the upper surface, especially on the wings, is minutely dotted, barred, and streaked, with white intermingled with buff and brown; and the ab- domen is white, barred along the flanks with brown. The wood Snipe has the general colouring of the plumage dark and sombre; the wings short; the abdomen and the whole of the under surface thickly barred with transverse lines of dark brown on a dusky white ground; and a tail of sixteen or eighteen, or very rarely twenty, feathers. Mr. Hodgson describes, with the greatest minuteness, each of these birds, and adverts with the fullest detail to their several habits and distinguishing peculiarities, as well of manners and of seasons as of form and plumage. Feb. 9.—A letter was read, addressed to the Secretary by M. Thibaut, and dated Malta, January 8, 1836. It communicated various particulars relative to the Giraffes belonging to the Society, which have recently been obtained by the writer and which are now in his custody, and may be translated as follows :— «« Having learnt, on my arrival at Malta, that you were desirous of information on the subject of the four Giraffes which the Society has entrusted to my care, I regard it as a duty to transmit to you a short statement, by which you will become aware of the difficulties that I encountered in obtaining and preserving for the Society these interesting animals, which are now, I hope, altogether out of danger. «« Instructed by Colonel Campbell, His Majesty’s Consul General ; in the Levant, and desirous of rendering available for the purposes of the Zoological Society the knowledge which I had acquired by twelve years’ experience in travelling in the interior of Africa, I quitted Cairo on the 15th of April, 1834. After sailing up the Nile as far as Wadi Halfa (the second cataract), I took camels, and- proceeded to Debbat, a province of Dongolah; whence, on the 14th of July, I started for the desert of Kordofan. « Being perfectly acquainted with the locality, and on friendly terms with the Arabs of the country, I attached them to me still more by the desire of profit. All were desirous of accompanying me in my pursuit of the Giraffes, which, up to that time, they had hunted solely for the sake of the flesh, which they eat, and of the skin, from which they make bucklers and sandals. I availed myself of the emulation which prevailed among the Arabs, and as the sea-: son was far advanced and favourable, I proceeded immediately to the south-west of Kordofan. “It was on the 15th of August that I saw the first two Giraffes. A rapid chase, on horses accustomed to the fatigues of the desert, put us in possession, at the end of three hours, of the largest of the two: the mother of one of those now in my charge. Unable to take her alive, the Arabs killed her with blows of the sabre, and, Xoological Society. 145 cutting her to pieces, carried the meat to the head-quarters which we had established in a wooded situation; an arrangement neces- sary for our own comforts and to secure pasturage for the camels of both sexes which we had brought with us in aid of the object of our chase. We deferred until the morrow the pursuit of the young Giraffe, which my companions assured me they would have no diffi- culty in again discovering. The Arabs are very fond of the flesh of this animal. I partook of their repast. The live embers were quickly covered with slices of the meat, which I found to be excel- lent eating. ** On the following day, the 16th of August, the Arabs started at daybreak in search of the young one, of which we had lost sight not far from our camp. The sandy nature of the soil of the desert is well adapted to afford indications to a hunter, and in a very short time we were on the track of the animal which was the object of our pursuit. We followed the traces with rapidity and in silence, cautious to avoid alarming the creature while it was yet at a di- Stance from us. Unwearied myself, and anxious to act in the same manner as the Arabs, I followed them impatiently, and at 9 o’clock in the morning I had the happiness to find myself in possession of the Giraffe. A premium was given to the hunter whose horse had first come up with the animal, and this reward is the more me- rited as the laborious chase is pursued in the midst of brambles and of thorny trees. ** Possessed of this Giraffe, it was necessary to rest for three or four days, in order to render it sufficiently tame. During this period an Arab constantly holds it at the end of a long cord. By degrees it becomes accustomed to the presence of man, and takes a little nourishment. To furnish milk for it I had brought with me fe- male camels. It became gradually reconciled to its condition, and was soon willing to follow, in short stages, the route of our caravan. “This first Giraffe, captured at four days’ journey to the south-west of Kordofan, will enable us to form some judgement as to its probable age at present; as I have observed its growth and its mode of life. When it first came into my hands, it was necessary to insert a finger into its mouth in order to deceive it into a belief that the nipple of its dam was there: then it sucked freely. According to the opinion of the Arabs, and to the length of time that I have had it, this first Giraffe cannot, at the utmost, be more than nineteen months old. Since I have had it, its size has fully doubled. “ The first run of the Giraffe is exceedingly rapid. The swiftest horse, if unaccustomed to the desert, could not come up with it un- less with extreme difficulty. The Arabs accustom their coursers to hunger and to fatigue; milk generally serves them for food, and gives them power to continue their exertions during a very long run. If the Giraffe reaches a mountain, it passes the heights with rapidity : its feet, which are like those of a Goat, endow it with the dexterity of that animal ; it bounds over ravines with incredible power ; horses cannot, in such situations, compete with it. “ The Giraffe is fond of a wooded country. The leaves of trees Third Series, Vol. 9, No. 52. August 1836. R 146 Zoological Society. are its principal food. Its conformation allows of its reaching their tops. The one of which I have previously spoken as having been killed by the Arabs measured 21 French feet in height from the ears to the hoofs. Green herbs are also very agreeable to this ani- mal; but its structure does not admit of its feeding on them in the same manner as our domestic animals, such as the Ow and the Horse. It is obliged to straddle widely ; its two fore-feet are gra- dually stretched widely apart from each other, and its neck being then bent into a semicircular form, the animal is thus enabled to collect the grass. But on the instant that any noise interrupts its repast, the animal raises itself with rapidity, and has recourse to im- mediate flight. « The Giraffe eats with great delicacy, and takes its food leaf by leaf, collecting them from the trees by means of its long tongue. It rejects the thorns, and in this respect differs from the Camel. As the grass on which it is now fed is cut for it, it takes the upper part only, and chews it until it perceives that the stem is too coarse for it. Great care is required for its preservation, and especially great cleanliness. “It is extremely fond of society and is very sensible. I have observed one of them shed tears when it no longer saw its com- panions or the persons who were in the habit of attending to it. « T was so fortunate as to collect five individuals at Kordofan ; put the cold weather of December, 1834, killed four of them in the desert on the route to Dongolah, my point of departure for Bebbah. Only one was preserved; this was the first specimen that I ob- tained, and the one of which I have already spoken. After twenty- two days in the desert, I reached Dongolah on the 6th of January, * 1835. « Unwilling to return to Cairo without being really useful to the Society, and being actually at Dongolah, I determined on resuming the pursuit of Giraffes. 1 remained for three months in the desert, crossing it in all directions. Arabs in whom I could confide accom- panied me, and our course was through districts destitute of every- thing. We had to dread the Arabs of Darfour, of which country I saw the first mountain. We were successful in our researches. I obtained three Giraffes, smaller than the one I already possessed. Experience suggested to me the means of preserving them. «« Another trial was reserved for me: that of transporting the animals, by bark, from Wadi Halfa to Cairo, Alexandria, and Malta. Providence has enabled me to surmount all difficulties. The most that they suffered was at sea, during their passage, which lasted twenty-four days, with the weather very tempestuous. « T arrived at Malta on the 21st of November. We were there detained in quarantine for twenty-five days, after which, through the kind care of Mr. Bourchier, these valuable animals were placed in a good situation, where nothing is wanting for their comfort. With the view of preparing them for the temperature of the country to which they will eventually be removed, I have not thought it ad- visable that they should be clothed. During the last week the Intelligence and Miscellaneous Articles. 14:7 cold has been much greater than they have hitherto experienced ; but they have, thanks to the kindness of Mr. Bourchier, everything that can be desired. « These four Giraffes, three males and one female, are so interest- ing and so beautiful, that I shall exert myself to the utmost to be of use tothem. It is possible that they may breed; already I observe in them some tendency towards mutual attachment. They are capable of walking for six hours a day without the slightest fatigue —G. T.” Mr. Gould, at the request of the Chairman, exhibited a specimen of the Trogon resplendens, Gould, and one of the Trog. pavoninus, Spix; and stated that he was indebted to the kindness of M. Nat- terer, who was present at the Meeting, for the opportunity of de- monstrating, by the juxtaposition of the Birds, the correctness of the determination which he had made in regarding them as distinct species. Mr. Gould directed particular attention to the several characters and distinguishing marks which he had pointed out to the Society on March 10, 1835, and which had subsequently been published in the ‘ Proceedings,’ part ill. p. 29 (Lond. and Edinb. Phil. Mag., vol. vii. p. 226.), and again dwelt especially on the fact that in Trog. resplendens the hinder feathers of the back, which are fully 3 feetin length, hang gracefully far away beyond the tail; while in Trog. pavoninus the lengthened feathers of the back are rarely equal in length to the tail: in only one instance has M. Natterer known them, in the latter bird, to exceed the tail by so much as a quarter of an inch. XXXII. Intelligence and Miscellaneous Articles. EFFECTS OF COMPRESSED AIR ON THE HUMAN BODY. D—D*: JUNOD has communicated to the Academy of Sciences the results of his experiments with compressed air. In order to operate on the whole person, a large spherical copper receiver is employed, which is entered by an opening in the upper part, and which has a cover with three openings ; the first for a ther- mometer, the second for a barometer or manometer, and a third for a tube of communication between the receiver and the pump. The air in the receiver is perpetually renewed by a cock. When the pressure of the atmosphere is increased one half, the membrane of the tympanum suffers inconvenient pressure, which ceases as gradually as the equilibrium is restored. Respiration is carried on with increased facility ; the capacity of the lungs seems to increase ; the inspirations are deeper and less frequent. In about 15 minutes an agreeable warmth is felt in the interior of the thorax. The whole ceconomy seems to acquire increased strength and vitality. The increased density of the air appears also to modify the circu- lation in a remarkable manner: the pulse is more frequent, it is full and is reduced with difficulty ; the dimensions of the superficial venous vessels diminish, and they are sometimes completely effaced, so that the blood in its return towards the heart follows the direction of the deep veins, The quantity of venous blood contained in the lungs R2 148 Intelligence and Miscellaneous Articles. ought then to diminish, and this explains the increased breathing of air. The blood there is then determined in larger quantity to the ar- terial system, and especially to the brain. The imagination becomes active, the thoughts are accompanied with a peculiar charm, and some persons are affected with symptoms of intoxication. The power of the muscular systemis increased. The weight of the body appears to diminish. When a person is placed in the receiver and the pressure of the air is diminished one fourth, the membrane of the tympanum is mo- mentarily distended; the respiration is inconvenienced, the inspira- tions are short and frequent, and in about 15 or 20 minutes there is a true dyspncea. The pulse is full, compressable and frequent ; the superficial vessels are turgid. The eyelids and lips are distended with superabundant fluids, and hemorrhage and tendency to syncope are sometimes induced ; the skin is inconveniently hot, and its functions increased in activity ; the salivary and renal glands secrete their fluids less abundantly —Journ, de Chim. Méd., June, p. 13. GASTRIC JUICE. Mons. H. Braconnot considers the gastric juice obtained from dogs to be composed of Ist. Free hydrochloric acid in considerable quantity. 2nd. Hydrochlorate of ammonia. 3rd. Chloride of sodium in large quantity. 4th. Chloride of calcium. 5th. Chloride of iron. 6th. Chloride of potassium, a trace. 7th. Chloride of magnesium. 8th. A colourless and pungent oil. 9th. Animal matter soluble both in water and alcohol, in consider- able quantity. 10th. Animal matter soluble in dilute alkalies. 1]}th. Animal matter soluble in water, but insoluble in alcohol; (the salivary matter of Gmelin). 12th. Mucus. 13th. Phosphate of lime. M. Blondelot has endeavoured to produce artificial digestions, at the temperature of the human body, by filling glass tubes, some with a mixture of bits of meat and gastric juice, and others with meat and water slightly acidulated with hydrochloric acid: in both cases the flesh preserved its primitive form and fibrous texture whilst quiescent, but by the slightest movement it was converted into a homogeneous mass precisely similar to chyme produced in the stomach.—Journal de Pharm., Feb. 1836. BIBROMIDE OF MERCURY. M. Lassaigne informs us that bibromide of mercury is less soluble in water than the bichloride, 105 parts of the former salt requiring 10,000 parts of water at 48° Fahr. to dissolve it, or rather more than 1 of salt to 100 of water; also that albumen forms with the bibromide Intelligence and Miscellaneous Articles, 149 a compound which remains in solution when diluted with 30 times its weight of water, whilst a solution of the bichloride of the same strength soon becomes troubled and precipitates. This non-precipitation of al- bumen will not only serve to distinguish the bibromide from the bi- chloride, but if bichloride of mercury is mixed with from 2th to+,th of its weight of the bromide, it will detect the adulteration.—Jour. de Chim. Méd., April. FLUORINE. M. Baudrimont states that he succeeded in isolating fluorine two years since; but he did not announce this discovery because he could not obtain it without a large admixture of oxygen gas. The process by which he first obtained fluorine was by passing fluoride of boron over minium heated to redness, and receiving the gasin a dry vessel. His present method is to treat a mixture of fluoride of calcium and binoxide of manganese with sulphuric acid in a glass tube ; but the gas thus obtained is mixed with the vapour of hy- drofluoric acid and fluosilicic acid gas ; this mixture however does not interfere with the observation of the principal properties of fluo- rine, which is a gas of a yellowish brown colour, and possesses an odour resembling chlorine and burnt sugar: indigo is bleached by it; it does not act upon glass, but combines directly with gold.— L’ Institut, 27th April, 1836. (See Messrs. Knox’s paper in the present Number.) ANTIMONIAL COPPER (fCLATANT). Henry Rose analysed this mineral after separating the quartz with which it was mixed, and found its composition to be Bulbs fy, ack ohne: 93 Soke 26°34 Antimonye.. At aac 46°81 Broney tain d-th need seo: 1:39 Copperas; Lwesdesaga 2 24-46 Leaties aceod aes aia «ete 0°56 which gives the formula Cu 4§ 6, analogous to the composition. of zinkenite and miargyrite.—L’ Institut, May 18, 1836. ON THE ACTION OF BROMINE UPON ETHER. M. Lowig added bromine to ether in successive small portions until it would not take up any more, and set the mixture aside for about a fortnight, when the ether was completely decomposed, giving rise to the following products, viz. : Ist, Formic acid. 2nd, Hydrobromic acid. 3rd, Hydrobromic ether, 4th, Dense bromic ether (schwerbromether), 5th, Bromal To separate these substances the decomposed liquor is to be di- stilled, The four first come over ; and if the operation is not pushed too far, the bromal remains in the retort mixed with a little dense bromicetherand hydrobromic ether, By treating this residue with 150 Intelligence and Miscellaneous Articles. water, and setting it aside for 24 hours, beautiful crystals of hy- drate of bromal are obtained. Bromal.—Anhydrous bromal is composed of Carbon. 1.0. iasseies 8°64 = 4 eqs. Hiydrageais,. 244.103 4. ose 0:34 =. 1 eq. Oegeem. Ji Gay ad tae © 633. = 2. eqs. Bromine? jeicoes es 8465 = 3 eqs. 100-00 The hydrate of bromal is formed of 1 eq. of bromal C* H! O? Brs 4 eqs. of water FF OF 1 eq. of hydrate of bromal-- C+ H® O° Br? When the hydrate of bromal is boiled with an alkaline solution, eqs. C’ H'° O' Br* form 2 eqs. of formic acid = C* H? O° 2 eqs. of bromoforme = C* H? Br 6 eqs. of water = Ere!) : Cs Hie Ove Bré Bromoforme decomposes into bromine and formic acid. Dense Bromic ther (schwerbromether). This is formed in great abundance in the decomposition of zther by bromine. It is very volatile, possesses a very penetrating and agreeable odour, and a sweet taste which remains for a length of time. It is much heavier than water, and even sinks in sulphuric acid. When it is boiled in this acid bromine is liberated, and a colourless fluid distils. Dense bromic zxther can be obtained anhydrous by di- gesting it with caustic potash, and distilling it repeatedly from quick-lime. It is perfectly clear, as limpid as water, and refracts light very powerfully. When passed over red-hot lime it is de- composed, liberating a gas which burns with a clear flame, and forming bromide of calcium. When it is boiled with a solution of potash, bromoforme is evolved, which is decomposed into formic acid and bromine, forming formiate of potash’and bromide of po- tassium. ‘The composition of this ether deduced from three ana- lyses, is Ist. 2nd. 3rd. Carbon...... 7°80 8°88 9°20 Hydrogen .. 1°43 1°30 1:36 Oxygen ..4.° 983 8:88 8°50 Bromine..... 80°94 80°94 80'94 100:00 100:00 100:00 These results indicate the following atomic constitution : 8 eqs. of Carbon ........ 49°04 8°52 8 eqs. of Hydrogen ...... 8:00 1-39 6 eqs. of Oxygen........ 48:00 8:37 6 eqs. of Bromine,....... 470°34 81-72 57538 10000 Intelligence and Miscellaneous Articles. 151 Bromic ether being the heaviest of the fluids resulting from the decomposition of ether by bromine, it is very easy to separate it from the other products. It is still tobe decided whether this is a separate compound, or a mixture of various substances.—Ann. de Chimie, March, 1836. ON THE COMPOSITION OF THE CRYSTALLIZED HYDRATE OF POTASH. M. Walter obtains hydrate of potash in fine crystals by pouring on three or four pounds of fused potash a little water, and when the mixture is cool, adding sufficient hot water to dissolve the re- mainder of the potash: at the expiration of 12 hours, by decanting the solution, the crystals will be found at the bottom of the vessel. The method of analysis adopted for determining the relative pro- portions of water and potash, was to neutralize a known weight of the crystals with hydrochloric acid, to evaporate the solution to dryness, and heat the resulting chloride of potassium to redness. 4065 gram. of crystallized potash afforded 3-207 gram. of chloride = 1-684 gram. of potassium; and as 1'684 gram. of potassium = 2:028 of potash (protoxide of potassium), the crystallized hydrate will be composed of 2-028 potash, 2-037 water, 4065 which nearly agrees with the formula of 10 eqs. of water to 1 of otash. 2 The slight difference between the experimental and the calculated results is evidently owing to a little interposed water, and some slight degree of humidity which the surfaces of the crystals acquired during weighing. There is also a third hydrate of potash, for 2-462 gram. of the crystals placed under the air-pump lost 0°527 gram., which indi- cates a compound of 21:4 water and 78°6 potash in 100 parts, or 1 eq. of potash.... 48 = 77:71 3 eqs. water...... 27 = 22:29 75 = 100:00 Thus crystallized potash appears to lose 7 eqs. of water in va- cuo.—Journ, de Pharm., June, 1836. Note.—How this crystallized hydrate can be regarded as a com- pound of 1 eq. of potash and 10 of water I am at a loss to know, as the ana- lysis approximates to 1 eq. of potash and 5 of water; but in any case the analysis does not indicate any atemic combination, for by it 48 of potash will combine with 48°3 of water, the equivalent of potash and water being respectively 48 and 49,—J. S. D. ON THE COMBINATIONS OF CHROMIUM WITH FLUORINE AND CHLORINE. Henry Rose has submitted the gaseous perfluoride of chromium 152 Intelligence and Miscellaneous Articles. of Unverdorben to a rigid examination. He obtained the gas by acting on a mixture of fluoride of calcium and bichromate of pot- ash by sulphuric acid ; the gas when passed into water contained in a platinum vessel afforded a solution of the chromic and hydrofluoric acids, from which he obtained 2°16 of fluoride of calcium = 1-031 of fluorine, and 0°339 of chromium. A second analysis afforded 3°02 of fluoride of calcium, and -729 of oxide of chromium: the mean of these analyses is, chromium 25°57, and fluorine 74°43, in 100 parts. Although the mode of analysis adopted does not admit of absolute certainty, yet it affords an approximation to the true composition utterly at variance with the existence of a perfluoride of chromium, the composition of which, to be analogous to chromic acid, would be Chromium........ 33°4: Fluorine pj eof. \4s 66°6 100:0 whilst, according to M. Rose’s analysis, the constitution of this substance approaches to a compound of 5, and not of 3 double eqs. of fluorine to 1 eg. of chromium, in which case it would be com- posed of Chromium........ 23°13 Hlnorines). 033/008 ‘87 100-0 Ifthis gaseous body is indeed a fluoride of chromium composed of 5 double eqs. of fluorine to 1 eq. of chromium, the existence of an analogous oxide of chromium containing 5 eqs. of oxygen and 1 eq. of chromium is not improbable. The chlorochlomic acid of Thomson, prepared by heating a mix- ture of common salt, bichromate of potash, and sulphuric acid to- gether, on analysis afforded from 1-241 gramme, 2+294. of chloride of silver, and 0629 of oxide of chromium, which indicate 45°6 of chlorine, 35°53 of chromium, and a loss of 18-87 in 100 parts. By a second analysis of this chloride prepared at another period, 3-33 of chloride of silver, and 0-975 of oxide of chromium were obtained from 1-802 parts, which results are equal to 45:59 of chlorine, and 37°95 of chromium per cent. ; and considering the deficiency as oxy- gen, this chloride according to the first analysis will be a compound of 2 eqs. of chromic acid and | eq. of chloride of chromium, which by calculation is equal to Chromium. has. 35°38 Chiotines\sh.ean: 44°51 Oxyren)is bia. ois 20°11 100°0 This substance is the only known instance of a volatile combina- tion containing chromic acid, and that, a volatile compound formed of an oxide and a chloride. M. Rose dissents from Thomson’s opinion in regard to the composition of this body, considering it to be a compound of chromic acid and chloride of chromium, and not a combination of chromic acid and chlorine; for if we consider with Thomson that all the chromium exists as chromic acid, there will be, if we adopt M. Rose’s analysis, an excess 0 1( per cent., which he attributes to impurity of the carbonate of soda employed by Thomson in his analysis. Tn endeavouring to prepare a compound of selenium analogous to Intelligence and Miscellaneous Articles. 153 the compound of chromium by treating mixtures of the seleniates and chloride of sodium with sulphuric acid, chlorine and chloride of selenium analogous to selenious acid were obtained ; and towards the end of the experiment green vapours rose, which condensed into an oily liquid composed of the selenious and sulphuric acids. - Bromide and iodide of potassium mixed with bichromate of pot- ash, and acted on by sulphuric acid, liberate respectively bromine and iodine in a state of purity without the slightest admixture of chromium.—Ann. de Chimie, January, 1836. ON THE ACTION OF SULPHURIC ACID ON OILS. M. Fremy in examining the kind of saponification which sulphu- ric acid exerts upon oil, has arrived at several facts in addition to those already ascertained by MM. Chevreul, Braconnot, and Ca- ventou. The oils employed were olive and almond, and the results from both were perfectly similar. When olive oil is treated with half its weight of concentrated sulphuric acid, surrounding the vessel with a freezing mixture to prevent any elevation of tem- perature and consequent evolution of sulphurous acid, the acid being added very cautiously, after a few minutes the mixture be- comes viscid, when the action is finished. Then the mass being treated with water, rather less than six times the bulk of the oil employed, the mixture separates into two strata; the superior is of syrupy consistence, whilst the lower is chiefly composed of water and sulphuric acid; this latter is a sulphoglycerate of lime(?), whilst the superior layer is a mixture of three acids, which he calls sulphostearic, sulphomargaric, and sulpholeic acids. The aqueous solution of these acids decomposes in a few days, sulphuric acid being formed, and the three fatty acids precipitated. The sulphostearic and sulphomargaric acids possess little sta- bility, as they always decompose in from 24 to 48 hours at most, which property M. Fremy has availed himself of to separate these two solid acids from the third, which is liquid, and is derived from the decomposition of sulpholeic acid. The two solid acids can be separated by means of alcohol; these he has named hydrostearic and metamargaric acids. Hydrostearic acid is solid, white, insoluble in water, soluble in both alcohol and ether, from which it crystallizes in mammillated groups; it fuses at about 129° Fahr. Its composition is C3 H72 O°: it loses £ an equivalent of water when in combination with bases, It may be volatilized without alteration, All its salts are insoluble in water, except the hydrostearates of soda and ammonia. Metamargaric acid is white like the preceding; soluble in alcohol; fuses at 120° Fahr. Its composition is given in the formula C%> H” O'. It loses $ an equivalent (14?) of water in combining with bases, and becomes C** H°7 O3, that is, exactly the same com- position as common margaric acid. Hydroleic acid isa slightly coloured liquid at 32° Fahr.; is com- posed of C*» H°* 04; loses 4 an equivalent of water by combination, and becomes C*> H® O°, When distilled it is almost totally de- composed into carbonic acid, water, and an oil composed almost 154 Intelligence and Miscellaneons Articles. wholly of two new hydrocarburets. These are liquid at ordinary temperatures; their composition is the same, but the density of their vapours differ, one boiling at 131° Fahr., the other at 226° Fahr. The first he has named oleene, the second elaene. Oleene is a white limpid fluid, burns with a vivid flame, and is composed of catbon 85°95, hydrogen 14:05, or CH*. Thus this hydrocar- buret appears to be isomeric with carbohydrogen, &c. &c. Elaene is white, less fluid than oleene, boils at 226° Fahr.: its odour is more penetrating than that of oleene, but its elementary composition is the same. It is insoluble in water, but dissolves in alcohol and zther. It combines with chlorine in the proportion of 4 vols. of chlorine to 4 of elaene. Hydroleicacid treated with concentrated sulphuric acid forms sul- pholeic acid, which’ is soluble both in water and alcohol, and of a slightly acid, and very bitter taste. The sulpholeates of the alkalies are soluble, but have not been crystallized. Sulpholeate of lime is composed of 2 eqs. of hydroleic acid, 1 eq. of sulphuric acid, 1 eq. of lime, and 1 eq. of water. From these experiments it appears that sul- phuric acid exerts a kind of saponifying influence on oil; forming glycerine, which combines in its nascent state with sulphuric acid ; and fatty acids, which form similar combinations. From the know- ledge that fat substances under such different actions always give rise to glycerine and fatty acids, M. Fremy argues that they are educts and not products preexisting in fatty bodies.—L Institut, May 11th. ON ETHAL. MM. Dumas and Peligot have analysed ethal with results similar to those of M. Chevreul; they find its composition to be Cano... 79-9 — €32 Hydrogen.... 142 = Hi’ Oxygen ...... 66 = O which when compared to alcohol by doubling the equivalents gives the formula Cc He + Ht Oz When ethal is distilled with anhydrous phosphoric acid it affords a product composed of Carbone ...... 6o-Z; p= ee Hydrogen’... I42 = He which is isomeric with olefiant gas, but exists in a different state of combination ; this substance they have named Cetene. They were not successful in obtaining a compound of cetene corresponding to zther, but have procured a substance analogous tosulphovinic acid. By heating ethal with sulphuric acid and fre- quently stirring the mixture they combine, forming sulphocetic acid. Sulphocetate of potash is a perfectly white salt, and occurs in pearly spangles ; it contains Sulphate of potash ... 240 = 1 eq. Sulphuric acid...... TW? soi oT, eg. RGAE ODES alae eueed «! gins 2 535 =” 64 eqs. Hydrogen.) -i..-'- ¢ 91 = 66 eqs. Lg a pe 21 1 eq. Intelligence and Miscellaneous Articles. 155 which accords with the formula S O°, KO + § O3, C#* He + H? O. They have also obtained a compound of chlorine and cetene by distilling together ethal and perchloride of phosphorus; the hydro- chlorate of cetene is composed of Carbon... 2.....0. "367 = C6 Hydrogen .. 12:32 = Hs Chlorme 83" 70" = eh These chemists consider spermaceti as a compound of margarate and oleate of cetene, in the proportions of 2 eqs. margaric acid, 1 eq, oleic acid, 3 eqs. of cetene, 3 eqs. of water, and give the following extraordinary formula, founded on an ana- lysis of Chevreul : 472 eqs. of carbon, 445 eqs. of hydrogen, and 14 eqs. of oxygen.—L’ Institut, May 4th. VOLATILE OIL OF THE BARK OF THE PRUNUS PADUS. This oil is a hydruret of benzule analogous to oil of bitter almonds: it affords by analysis Carbon+--- 79°34 = 14 eqs. Hydrogen.. 568 = _ 6 egs. Oxygen .. 1498 = 2 egs. 100:00 M. Lowig observes that when this oil is placed in contact with potassium on mercury, the potassium darts rapidly about and soon disappears, the oil becomes deeper-coloured and at last viscid without any visible disengagement of gas.— Ann, de Chimie, March, 1836. ON THE ACTION OF OXALIC ACID ON THE SULPHATES OF IRON AND COPPER. When a concentrated solution of oxalic acid is poured into one of protosulphate of iron, the liquid assumes a yellowcolour, and pre- cipitates after standing for some time. ‘This precipitation does not occur in a solution of the persulphate by the addition of oxalic acid ; and in general ferruginous salts are not precipitated either by ox- alic acid or by oxalate of ammonia. These phenomena have already been noticed by M. A. Rose; but M. Vogel of Munich wishing to know whether the decom- position was complete or only partial, instituted a series of expe- riments, from which he concludes that oxalic acid entirely decom- poses the sulphates of iron and copper, setting at liberty the whole of the sulphuric acid, its affinity for these oxides being greater than that of even sulphuric acid. The oxalate of iron obtained is a yellow powder almost insoluble in water, which when heated to redness in a closed vessel leaves a residue of protoxide and car- 156 Intelligence and Miscellaneous Articles. buret of iron. The oxalate of copper is a blue powder insoluble in water, which heated to redness affords metallic and protoxide of copper.—Jour. de Pharm., April, 1836. LOCALITY OF NATIVE MERCURY. M. de Bonnard has communicated to the Philomathique Society of Paris, a notice by M. Alluaud, sen. of Limoges, respecting the mercury of Peyrat-le-Chateau, department de la Haute-Vienne. This metal is found in the native state ina disintegrated granite, which forms the esplanade of the ancient castle of Peyrat, on the side of the royal road from Figeac to Montargis. M. Alluaud describes the nature of the soil of the country, which is entirely formed of various kinds of granite passing into each other, as kaolen and gneiss, &c. On the esplanade of the castle of Peyrat, M. Ranque, in clearing the soil and digging the foundation of a house, found twelve pounds of native mercury, and other persons also foundsome. M. Alluaud having made several excavations and also examined the places, found the mercury disseminated in a fine- grained granite, which was very quartzose, and the felspar was de- composed. The metal does not exist throughout the rock, but only in parts of it; no bed, vein, or fissure can be perceived. The metal has been found at several distinct places, far from each other and without any communication ; this circumstance is unfavourable to the idea of an accidental infiltration from above, for in this case the metal would have occupied a circumscribed situation in some fissure of the rock. Notwithstanding the singularity of this locality of native mer- cury ina primary rock which contains no indications of cinnabar, and difficult as it is to draw a conclusion from an isolated obser- vation confined to the narrow space of a few feet, M. Alluaud does not hesitate to pronounce either that the mercury is disseminated in the rock in small masses, irregular both as to form and extent, and in this case that the deposit has been contemporaneous with the formation of the rock; or that it occupies fissures in the rock, which are now imperceptible, into which it was subsequently conveyed by sublimation from the interior of the earth_—L’ Institut, No. 160. DONIUM, A NEW METAL CONTAINED IN DAVIDSONITE. This mineral was discovered by Dr. Davidson of Aberdeen, in a granite quarry in the neighbourhood of that city; it has been ex- amined by Mr. Thomas Richardson, and he concludes that he has obtained from it a metal which differs from any previously known. «From the alkaline and earthy bases, and from several of the metallic ones, it is eminently distinguished by the green precipitate which it gives with sulpho-hydrate of ammonia ; while its solubility in the caustic alkalies, and in carbonate of ammonia, the light brown precipitate thrown down by sulphuretted hydrogen, and the green given by sulpho-hydrate of ammonia, are amply sufficient to distinguish it from all the others. Intelligence and Miscellaneous Articles. 157 “If this substance be considered as sufficiently distinct, which, from its characters, I think T am warranted to conclude, I shall propose to give it the name of Donium, being a convenient contrac- tion of Aberdonia, the Latin name of Aberdeen, near which place Davidsonite occurs; for the suggestion of which name I am in- debted to Dr. Thomson. «The change of colour which the precipitates of this substance undergo, during the process of washing, appears to be owing to different degrees of oxidation; and with a view to determine, if possible, the characters of the metal itself, as well as its degrees of oxidation, the following experiments were made: «A. Over a portion of the white oxide strongly heated to red- ness, in a green glass tube, a current of dry hydrogen gas was passed, for nearly an hour. The whole was converted into a slate- blue mass, while aqueous vapour was evolved at the end of the tube: 100 parts of the white powder, by this means, lost 16°34 of their weight. «‘B. A portion of the buff oxide was treated in the same way, and the same slate-blue powder was obtained, with the evolution of aqueous vapour: 100 parts of this oxide lost, by this process, 5:11 of their weight. ; ‘«« The substance possessing the slate-blue colour exhibited the fol- lowing characters : «<1. When pounded in dry agate mortar, it appeared to assume a lustre, resembling the metallic. **2. When heated to redness, it glowed like tinder, and became white. «3. In dilute muriatic acid, it effervesced, and was converted into white powder. «<4. When placed in a charcoal crucible, properly inclosed, and heated strongly in a forge for half an hour, it was not altered. «It seems probable, that the slate-blue substance consisted of metallic donium, but ina state of intimate division; while from the experiments made upon the oxides, upon which, however, for many reasons, great confidence cannot be placed, it would appear that the oxides are composed of 1. The Buff . . 9489 Donium + 5:11 oxygen. 2. The White . 83°66 Donium + 16°34 oxygen, Or, that the white oxide contains thrice as much oxygen as the buff. «Although circumstances do not permit of my continuing this investigation, I have reason to believe that it will not be laid aside, but that a more full account of this substance will shortly be given by an individual much more capable of performing the task.”— Records of Science, June, 1836. GEOLOGY OF MANCHESTER. Professor Phillips, in a recent examination of this neighbourhood with reference to the question of the geological age of the lime- stones and shelly marls, which has lately attracted much attention, 158 Intelligence and Miscellaneous Articles. has ascertained that the limestone of Ardwick, usually classed with the magnesian limestone, is in truth (as Dr. C. Phillips of Man- chester had previously stated to him) a part of the coal formation of Lancashire. He has discovered in it the bones of a reptile, per- haps the most ancient yet known in Great Britain. A vast number of parts of fishes (including Megalichthys Hibberti), shells, several and many plants of the ordinary coal shales have also been collected by himself, Dr. Phillips, Mr. Looney, Mr. Wm. Williamson, and others. Some of the results of these inquiries, which lead to im- portant inferences as to the possible extension of coal works in the midland counties, will be offered to the British Association at Bristol, August 22, 1836. EHRENBERG’S NEW DISCOVERY IN PALEONTOLOGY: TRIPOLI COMPOSED WHOLLY OF INFUSORIAL EXUVIE. At the sitting of the Royal Academy of Sciences of Paris, July 11th, the following letter was communicated, dated Berlin the $rd of July, from M. Alexander Brongniart :—* I have today be- come acquainted with a discovery entirely new, for which we ate indebted to M. Ehrenberg, and which he has demonstrated to me in the clearest manner ; it is that the rocks of homogeneous appear- ance which are not very hard, friable, even fissile, entirely formed of silex, and which are known by the names of tripoli, more or less solid (Polierschiefer of Werner, )are entirely composed of the exuvize or rather of the perfectly ascertained skeletons of infusorial animals of the family of the Bacillarie and of the genera Cocconema, Gompho- nema, Synedra, Gaillonella, &c, These remains having perfectly pre- served the forms of the siliceous carcases of these infusoria, may be seen with the greatest clearness through the microscope, and may easily be compared with living species, observed and accurately drawn by M. Ehrenberg. In many cases there are no appreciable distinctions. The species are distinguished by the form, and still more surely by the number of septa or transverse lines which divide their small body ; and M. Ehrenberg, who has been able to count them by the microscope, has observed the same number of these divisions in living and in fossil species. They are the tripolis of Bilin in Bohemia, of Santa-Fiora in Tus- cany, and of other places which I do not remember with certainty, (of the Isle of France and of Francisbad near Eger, if I am not mis- taken,) which have given occasion to these curious observations. The slimy iron ore of marshes is almost wholly composed of Gazilo- nella ferruginea. The greater part of these species are lacustrine, but there are also some marine, particularly in the tripoli of the Isle of France.— L’ Institut, No. 166. _—_ BRITISH ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE. The next Meeting will be held at Bristol during the week com- mencing on Monday, August 22nd; the Members of the General Committee will assemble on the preceding Saturday. Meteorological Observations. 1'59 SCIENTIFIC MEMOIRS, Part I. We have to announce the publication of the First Part of a new periodical work, conducted by Mr. Richard Taylor, assisted by Mr. E. W. Brayley, junr., entitled SCIENTIFIC MEMOIRS, szzecrep FROM THE TRANSACTIONS OF ForEIGN ACADEMIES OF SCIENCE AND LEARNED SOCIETIES, AND FROM ForEIGN JouRNALS. This work may be considered as supplementary to the PurtosopHican Macazine and other scientific journals; and will give in an economical form translations of papers of great interest, but which may exceed the limits of those publications. The following are the contents of the First Part: Memoir on the Free Transmission of Radiant Heat through dif- ferent Solid and Liquid Bodies. By M. Melloni.—New Researches relative to the Immediate Transmission of Radiant Heat through dif- ferent Solid and Liquid Bodies. By M. Melloni.—Experiments on the Circular Polarization of Light. By H. W. Dove.—Description of an Apparatus for exhibiting the Phenomena of the Rectilinear, Elliptic, and Circular Polarization of Light. By H. W. Dove.— Memoir on Colours in general, and particularly on a new Chromatic Scale, deduced from Metallochromy for Scientific and Practical Pur- poses. By M. Leopold Nobili.—On the Mathematical Theory of Heat. By M. S. D. Poisson.—Researches on the Elasticity of Bodies which crystallize regularly. By M. Felix Savart——Experiments on the Oil of the Spiraea Ulmaria (Meadow-Sweet). By Professor Léwig. —Researches relative to the Insects, known to the Ancients and Moderns, by which the Vine is infested, and the means of preventing their Ravages. By the Baron Walckenaer. METEOROLOGICAL OBSERVATIONS FOR JUNE 1836. Chiswick.—June 1. Overcast. 2, Cloudy and fine: rain at night. 8. Cloudy. 4. Fine. 5. Fine: showery. 6. Very fine. 7. Over- cast. 8. Very fine. 9. Fine: slight rain. 10. Overcast: rain. 11—14. Veryfine. 15. Hot and dry: lightning at night. 16. Very fine. 17. Fine: thunder showers at noon in heavy drops. 18. Very fine. 19. Fine. : thunder showers. 20. Fine. 21. Cloudy. 22, Rain: overcast and fine. 23. Fine. 24, Fine: thunder storm in afternoon : clear atnight. 25.Showery. 26,27. Very fine. 28—so. Hot and dry. Boston—June 1, Cloudy. 2. Cloudy: rain p.m. 3. Cloudy: thunder and lightning with rane. 4, 5. Cloudy: rain p.m. 6. Fine: rain p.m. 7—9. Cloudy. 10. Cloudy and stormy. 11. Cloudy: rain early a.m. 12. Fine: rain pm. 13, 14. Cloudy. 15. Fine. 16. Fine: rain earlya.m. 17. Fine: raine.m. 18. Cloudy: rainearly am. 19. Fine: raine.M, 20,Cloudy. 21.Stormy:rainr.m. 22, Cloudy: rain a.m. 23. Fine. 24, Cloudy: rain P.M, 25, Stormy, 26, 27. Cloudy. 28—30. 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L6S-6z | PVL-6z | 9EL-6Z nie 0S 9 5 : 998-67 | 626-60 | Lz6-6z 'T “LYBT JO saaadap fe ea “UTTAL | “XPJAL I V Te “ULI ur‘ 6 | “40980 | -asiy9 | -o0g “ko | 35 Say Fectcbin Wy #g\-—— | Buurersigargias | “AUP wy is ae “QUOTA jo skeqy ‘20g “hoy :‘puoT : uopuo'y NSO | ej0g “Koy : wOpuo'T *yuiod-aaq Ue yy *PUIAA *JOVUIOULIY,T, “1oJa WOE, ‘u0p80g JD TIFIA “py hq pun fuopuorT avau ‘younsiyy yo Ayaroog 72.Nq]NIy LOFT e ayy fo suapany) ayy 1 NosdOH,L “yy hq £ humjpasoay quojsissp ayy hg hynoog qohoy ay7 fo squauplndpy ayy wo apnue suoYywaLasgQ 109290]0109/2 IT THE LONDON anp EDINBURGH PHILOSOPHICAL MAGAZINE AND JOURNAL OF SCIENCE. [THIRD SERIES.} SEPTEMBER 1836. XXXIV. On such Functions us can be expressed by Serieses of periodic Terms. By James Ivory, Esq., M.A, F.R.S.* ~~ was any speculation ushered into the mathematical world with more unmeasured praise than the analytical theory of Laplace for the attraction of spheroids approaching nearly to spheres. The very general nature of the processes, and the arriving at results by differentiations merely, without tedious and difficult integrations, called forth the admiration of every geometer. It is not the present intention to inquire whether the expectations raised by so novel a method of in- vestigation, have been fulfilled: but it cannot be denied that the grounds of it are obscure, and have never been demon- strated so as to remove every doubt. ‘The subject having been again brought forward, it is very desirable that it should not now be dismissed without a full elucidation. The method of Laplace was first published in the Memoirs of the Academy of Sciences in 1782, and afterwards in the third book of the Mécanique Céleste. Objections having been made impugning the generality of the investigation, the author returned to the subject in the eleventh book of the same work, which appeared in 1823. He now greatly restricts the de- monstration before given in the third book: insomuch that according to the new proofs the method is less general than * Communicated by the Author, Third Series. Vol. 9. No. 53. Sept. 1836. Ss 162 Mr. Ivory on such Functions as can be that subordinate part of the first theory which is well demon- strated, and about which there is no dispute. Thus we have the direct testimony of Laplace that his method was ori- ginally extended beyond its just bounds. On the contrary M. Poisson has always contended for the exactness of the theory in its fullest extent. He undertook to clear it from all objections by giving an unexceptionable demonstration of it, first in the nineteenth cahier of the Journal de l’ Ecole Poly- technique, published in 1823, next in the additions to the Conn. des Tems for 1829, and very lately in his Theory of Heat. Prof. Airy also turned his attention to this subject in the Cambridge Transactions for 1826. He thinks that the ge- neral theory of Laplace is strictly proved; but he maintains that it can be applied only to such expressions as are suscep- tible of no more than one development. By means of this modification he arrives at the same conclusions which are stated by Disjota in this Journal for last month (p. 84). But no- thing can be more clearly proved than that no function can pos- sibly have more than one development; which sets aside the sug- gestion of the Professor ; who must, therefore, be ranked with those that admit the unrestricted theory of Laplace. Mr. Bowditch, in his excellent Translation, limits the general equa- tion of Laplace, which applies to an attraction proportional to the mth power of the distance, by excluding all negative values of x from —2 to — 3; and, by so doing, he has brought this curious but slippery speculation one step nearer the grasp of the human mind. Confining his attention to the law of at- traction that prevails in nature, he attempts to prove the ac- curacy of Laplace’s method in all its generality, drawing his arguments chiefly from geometrical considerations. It will be sufficient to remark here, that the nature of the function ex- pressing the height of the molecule does not depend upon any integral taken between very small limits; but, as Laplace has clearly stated*, upon this, that the differentials shall in- variably continue to be infinitely small as the molecule ap- proaches the contact of the two surfaces. It will not be ne- cessary to examine all the demonstrations enumerated ; for they all turn upon the sense, more or less extensive, in which one equation is to be understood. It will be sufficient to dis- cuss the investigation of M. Poisson, which is adopted by M. de Pontécoulant in his Traité du Systeme du Monde. The question is fairly stated by Disjota in the last Number of this Journal. The value of X’, which is the limit of the integral X when « = 1, is shown to be a Series, determinate in its form, all the terms of which satisfy an equation in partial * Méc. Cél,, tom. vy. pp. 25 & 26. expressed by Serieses of periodic Terms. 163 differentials; and it is further proved that the characteristic property of the terms of the series is independent of the ex- pression /(4, ~), being derived entirely from the functions P; produced by the expansion of the radical. ‘The plain in- ference seems to be, that it will be impossible to deduce ge- nerally the value of /(@,~) from a series the distinguishing character of which is independent of that function: yet this is what M. Poisson undertakes to accomplish by an artifice of calculation. The formulas of M. Poisson are these*, viz. 1 x 2% (1—a) f(H,Y') sing’ dda! se (l—2a pa’)? (1.) Pp = cos 6 cos # — sin 6 sin & cos (Y—wy’), « being less than 1, but approaching to it indefinitely: and from this it is proposed to deduce, in the most general manner, the equation RS 7 Cs, Ws (2. X’ representing the value of the double integral X when Goh. If we suppose that f (4, Y’) is constant in the small extent for which the increments of X are sensible, the first of the equations (1.) may be thus written: r lx eaee gt 1 ! U Lf mes (4s ff (1—e’*) sin §' dé OP 7IO0S0 = (1—2ap+a?)? which will coincide with the equation (2.), because the value of the integral is 1 when « = 1, as it is easy to prove in many ways. Now it is presumed that /(6’,)’) may be supposed constant, because the numerator of the differential is always small on account of the small multiplier (1—2?), while the de- nominator increases rapidly, and quickly becomes so consi- derable as to make the increments of the integral insensible. Such is the demonstration of M. Poisson as it appeared in 1823 in the Journal del Ecole Polytechnique. In the Conn. des Tems for 1829, and in the Theory of Heat the author, in order to make the matter plainer, supposes that the arcs §’ and vary from the initial values @ and to §+y and f +z, y and z being small increments: in consequence S(O) =f (4+y% b+z2) =f (4v)+¢: and by substitu- ting this value in the first of the equations (1.), we obtain X’ =f (6 v) + X", x" =f" =(1—a*) ¢ sin fat aie 0 0 (1—2ap+a*)? \ * Théorie de la Chaleur, p. 213. S2 164 Mr. Ivory on such Functions as can be supposing that all the quantities under the double sign of in- tegration are expressed in terms of the two variables y and 2, and that « is made equal to 1, after the integrations. This transformation is correct; and the introducing of the new integral is important, as it leads to detecting the fault of the investigation. M. Poisson assumes that the differentials of the new integral X" are all infinitely small, so long as @ is in- finitely small: in which case, X" being itself infinitely small, it may be rejected, and the same conclusion will be obtained as in the first investigation. Now were the denominators in the successive differentials of X" always finite quantities, the assumption of M. Poisson would be allowable; but as both the numerators and denominators begin to vary from zero, it is not impossible that, while the first increase to a finite magnitude, and the others to some small quantity B, the quotients may pass through every gradation of quantity; their values may be infinitely small, or finite, or infinitely great: This point must therefore be examined before any just conclusion can be drawn. Let v= f (6, ), wf = f (6, v'); then = u'—u: put also g = 1—a; then 1—e=2 [iy oe ¢ 1—2ap+oa° = 2(1—p)—2g(1—p)+¢g". These values being substituted, the resulting expression of X" will be, 2e—g°).uw—u.sin dildy' ew fag Bi es g°) ee ovo (2 (1—p)—2g (1—p) + g°)? Now 1—p is a small quantity depending upon the values assigned to y and z; and g is’a small quantity quite inde- pendent of any other; we may therefore suppose that ¢ is equal to 1—p, or less than it, and even infinitely less than it. Now, ¢ being any positive number less than 3, if we reject quantities of the second order in the last formula, the result may be thus written : zs 2g ul —u in 6d 6! Xr [7 [ *—"S—_ x_—___,— x sn Vd da’, SSo (g(1—p))” (ap)? which is obviously the limit to which the expression of X! continually tends as values decreasing indefinitely are assigned to y, %, g. Since g may be considered infinitely less than 1—p, the ultimate value of the factor is always & (2(1—p))* expressed by Serieses of periodic Terms. 165 zero: but distinctions must be made with regard to the other factor. When the value of . ul—u (g1— 7) Lae is either always finite or infinitely small, all the differentials of X” will be infinitely small as assumed by M. Poisson, and the equation (2.) will be proved. But the same equation will not be proved if the limit of the same factor be either infi- nitely great, or if it be a quantity that cannot be generally determined, and of which it cannot be said that it is either finite, or infinitely great. If ¢ = 1, the factor in question will be, w—u VW 2(1—p)’ which has a finite value when u, or f (8, {) is a finite function of cos 6, sin@ cos, sin@ sin. This readily follows from the usual transformation of such expressions. The same factor will be infinitely small when wu!'—w is divisible by (1—p)", 2 being any positive integer. In all these cases the equation (2.) is demonstrated. If n = 1, or if u/—u be divisible by 1—p, we fall upon the instance particularized by Laplace in the eleventh book of the Mécan. Céleste. But if uw, or f(,), be not a finite function of cos 6, sin @ cos {, sin @ sin f, no determinate value can be assigned to the factor : ul—u (91 7 RE e.? geet ’ au ” j ‘ a Researches into the Physiology of the Human Voice. 201 those of the corresponding parts of a buffalo. The dimensions compared with those of the buffalo and camel are thus: Sivatherium. Buffalo. Camel. Depth of the jaw from the alveolus last molar 4:95 in. 2°65 in. 2°70 in. Greatest thickness of do. ........-..-2+0-+- 2:3 1:05 14 Width of middle of last molar .............. 1:35 = 0°64 0°76 Length of posterior 3d of do. .........---.. 215 0:95 1:15 No known ruminant, fossil or existing, has a jaw of such large size; the average dimensions above given being more than double those of a buffalo, which measured in length of head 19:2 inches (-489 métres); and exceed- ing those of the corresponding parts of the rhinoceros. We have there- fore no hesitation in referring the fragment to the Sivatherium giganteum. The above comprises all that we know regarding the osteology of the head from an actual examination of the parts. We have not been so for- tunate hitherto, as to meet with any other remain comprising the anterior part of the muzzle either of the upper or lower jaw*. We shall now pro- ceed to deduce the form of the deficient parts, and the structure of the head generally, to the extent that may be legitimately inferred from the data of which we are in possession. [To be continued. ] XLII. Experimental Researches into the Physiology of the Human Voice. By Joun Bisuop, Esq., Sc. Sc. (THE human voice is a subject of universal interest, and at- tracts the attention of numerous individuals in every class of society. The facility with which its organs are brought into play, and the perfect ease with which its various tones are produced, convey no idea of the complex and elaborate me- chanism by which they are effected, nor of the extreme intri- cacy in which the phenomena are involved. Few perhaps are aware that the subject of the voice has been the cause of more laborious research and hypothetical reasoning, attended with more perplexing results, than almost any other object of inquiry connected with animal physiology. The term voice is exclusively appropriated to those sounds which are produced by the vocal organs of animals. These sounds are of two kinds, namely, first, the primary inarticulate tones, with all their modifications of character, quality and in- * In a note received from Captain Cautley while this paper is in the press, that gentleman mentions the discovery of a portion of the skeleton ofa Sivatherium in another part of the hills : See Journal As. Soc. vol. iv. ‘ During my recent trip to the Sidwliks near the Pinjor valley, the field of Messrs. Baker and Durand’s labours, I regretted much my inability to obtain the dimensions of one of the most superb fossils I suppose that ever was found. It was unfortunately discovered and excavated by a party of workpeople employed by a gentleman with whom I was unacquainted; and although I saw the fossil when in the rock, I was pre- vented from getting the measurements afterwards. ‘This specimen appeared to consist of the femur and tibia, with the tarsal, metatarsal, and phalanges of our Sivatherium.” It is much to be regretted that such an opportunity should have been lost of adding to the information already acquired of this new and gigantic ruminant.—Sec. Asiat. Soc. + Communicated by the Author. Third Series, Vol. 9. No. 53. Sept, 1836. Z 202 Mr. Bishop’s Experimental Researches into tensity, including the key or pitch and the whole range of mo- dulation; And, secondly, the interrupted sounds, or voces limitatze, which constitute articulate language. To the former division of these functions the following ob- servations are applied. The difficulties which for more than twenty centuries have obstructed the elucidation of this interesting branch of natural philosophy, may be ascribed to two principal causes. First, The organs of voice, when anatomically examined, are found to be extremely complex, including portions of a system which is adjusted to perform several of the most important functions of the animal ceconomy. Secondly,’ Thestateof acoustic science is not yet sufficiently ad- vanced to estimate all the effects resulting from air in conjunction with an elaborate series of elastic bodies in producing sounds. The former of these difficulties has been in a great measure removed by Albinus, Bichat, Majendie, and others, and the latter have been considerably reduced by the investigations of M. Felix Savart. Many of the phzenomena of the voice, however, yet remain unexplained, and abound with subtile intricacies. Several of these which are of fundamental importance, the details of which this memoir consists, will, I trust, tend to illustrate. The organs which are associated in the performance of the functions of the voice are principally the lungs, the trachea, the larynx, pharynx, nostrils, and the mouth with its appendages. In reference to the vocal organs, the lungs may be regarded as a receptacle of air for their supply. The Trachea is nearly a cylindrical pipe forming the Porte- vent and the connecting link between the lungs and the larynx. Its anatomical structure is well known, but its office, with re- spect to the voice, has hitherto been very imperfectly under- stood. It varies in length and diameter with the sex and age of the individual. In the adult male it is about four inches and a half in length, and from six to eight tenths of an inch in diameter: in the female, the length is about four inches, and the diameter from nine to eleven twentieths of an inch. It is open at both ends, for the free transmission of air; its lower extremity having a double embouchure called bronchia, which diverge at an angle of about fifteen degrees from the axis of the trachea. The areas of the bronchial tubes are collectively greater than that of the trachea, owing to which the condensation of the air in the latter is more rapidly effected, and the voice acquires, according to M. Savart, a roundness and fulness which it would not otherwise have possessed. Lond & Edin Pit Mag. Vol. 9 Fl. 3 x Vocat lub the Physiology of the Human Voice 203 The important properties of the trachea with respect to the voice are its elasticity, its power of suffering elongation and con- traction, as well as of increasing or diminishing its diameter, and the adaptation of its surface to vibrate in unison with the glottis. The Larynz js situated on the top of the trachea, and forms the superior termination of the vocal tube. Its mechanism and functions are exceedingly complicated, and furnish fit subjects both for anatomical and for philosophical discussion. It is the most important organ of the voice, and its struc- ture requires to be well understood before its functions can be satisfactorily explained. Some brief anatomical details will therefore here be introduced. The larynx is a cartilaginous tube situated in the anterior part of the neck, and separated from the cervical vertebrae by the pharynx, within which it has a motion resembling that of the slides of a telescope. Its fi- gure, although difficult to describe with precision, is symme- trical: broad and capacious in its superior chamber, it becomes narrower at its lower termination, where it is joined to the trachea, and presents externally an appearance-very dissimilar to its internal conformation. The frame of the larynx is composed of elastic cartilages, articulated with each other by fibrous and muscular bands in such a manner as to allow a free passage for the transmission of the air in respiration, as well as that mobility which is ne- cessary to the production of the voice. ‘They are five in num- ber: the Thyroid, the Cricoid, the two Arytenoid cartilages, and the Epiglottis. The Thyroid*, the largest of these cartilages, lies in the front of the larynx, where it seems both to shield the internal me- chanism from injury, and to contribute to its peculiar function. It is composed of two lateral portions united at the mesial line, where they form an angle more or less acute. These lateral surfaces are nearly smooth, and terminate in four borders; the superior connected by ligaments with the os hyoides, and the inferior with the cricoid cartilage ; whilst the two posterior bor- ders give attachment to some fibres of the Stylo- and Palato- Pharyngei muscles, and send off four angular processes, two of which are connected by ligaments with the extremities of the os hyoides above, and two with the cricoid cartilage below. The Cricoid Cartilage*, situated at the bottom of the la- rynx, serves by its annular shape and dense structure to form the solid portion of the vocal tube. It is narrow anteriorly, where it is connected with the thyroid, from which point it becomes gradually larger, and presents posteriorly a broad portion, on the most elevated part of which are seen two oblique * Plate IIL, Fig. 1. Z2 204 Mr. Bishop’s Experimental Researches into and convex articular surfaces on which the arytenoid cartilages rest: ridges appear on the outside of the cricoid for the in- sertion of muscles, and its inferior margin is joined by a fibro- cartilaginous membrane to the first ring of the trachea. The Arytenoid Cartilages* are two exceedingly irfegularly shaped bodies, situated at the posterior, inner, and upper sur- face of the cricoid; their figure approaches somewhat to the pyramidal and triangular; their posterior surfaces, to which are attached the oblique and transverse muscles, are concave ; they have likewise a concave surface anteriorly, especially to- wards the lower part, where they are contiguous with a cor- responding portion of the arytenoid gland. Their internal surfaces are closely connected with the mucous membrane of the larynx: the planes of these surfaces are perpendicular to the axes of their motion, and adapted to approximate closely with each other. They are terminated by three ridges, one internally, the second externally, and the third anteriorly, whick last abounds with inequalities. The bases of the ary- tenoid cartilages have curved, grooved, oval, articular sur- faces, which are furnished with synovial membranes; the grooves are directed downwards, and outwards, corresponding with the convex articulating surface of the cricoid. In front of these cartilages are two conical or pyramidal prominences, forming the posterior part of the chink of the glottis; these prominences project over the tube, about four twentieths of an inch in the male and about three twentieths in the fe- male. At the point of these projections there are often small distinct cartilages, which give attachment to the thyro-aryte- noid ligaments. ‘The perpendicular projections of these bo- dies have also on each of their summits a small, distinct, iso- lated cartilage united by perichondrium. The arytenoids are endowed with extensive freedom of motion, including a rota- tory motion, a sliding one transverse to their axes of rotation, and an oblique tilting motion, They are destined for the at- tachment of several muscles, whose forces aré directed to re- gulate the movements of the glottis, and the modulations of the voice. The £piglottist isa fibro-cartilage occupying a position be- tween the summit of the larynx and the base of the tongue. It is articulated to the superior margin of the angle formed by the union of the lateral portions of the thyroid cartilage, and in its passive state stands almost perpendicular, but assumes a horizontal direction when the larynx is raised in the act of deglutition. In form it has been aptly compared to the leaf of an artichoke; and on both surfaces, but more especially on * Fig. 1. + Fig. 4. the Physiology of the Human Voice.” 205 its laryngeal surface, are found numerous minute orifices in which glands lie imbedded. The epiglottis is repressed by. two pair of small muscles called the Aryteno-Epiglottidez, and the Thyro-Epiglottidei. 'The effect arising from the depres- sion of the epiglottis upon the fundamental key of the vocal tube is somewhat uncertain. Majendie and Mayo* have in- ferred from the experiments of M. Grenié ¢ that the epiglottis prevents the tones of the voice from becoming more acute when they increase in intensity; this hypothesis is however de- cidedly erroneous f, in as much as neither the elevation nor de- pression of the epiglottis can affect or regulate the vibrations of the glottis. : The Thyro-Arytenoid ligaments§, or chorde vocales, as they are commonly (though improperly) denominated, are com- posed of fasciculi of parallel fibres arising from the bases of the arytenoid cartilages ; thence proceeding forwards and inwards, they meet, and are inserted together into the posterior surface of the thyroid cartilage at the junction of its alae. These ligaments are immediately after death almost trans- parent, and nearly inelastic. ‘These characters, however, very svon disappear by exposure to the air, and they become opake, and yielding. ‘Their length on an average, in the adult male, is six lines, and in the female four and a half lines. The chink formed by the separation of these ligaments is the Rimula Glottidis. 'The form of this chink in a state of relax- ation is elliptical, but when the cartilages are widely separated it assumes the form of an isosceles triangle. ‘The breadth of the chink when relaxed is about three lines. The movements of the larynx are effected by two sets of muscles; the one at- tached principally to the os hyoides, which is the centre of mo- tion of all these parts and serves to raise and depress the vocal tube; the other is destined to control the movements of the * Vide Mayo, Physiol., p. 334. + “ M. Grenié a trouvé qu’on pouvait corriger ce défaut en mettant au- dessus des anches, dans le tuyau vocal, des petites lamelles de papier, fixes seulement par leur base, et qui, s’élevant quand le courant s’accélere, s’abais- sant quand il se ralentit, peuvent, par ces positions diverses, modifier les on- dulations de maniére que le ton reste constant, avec une intensité de son différente.” —Précis Elémentaire de Physique Expérimentale, par J. Biot, page 399. J According to Liscovius (p. 34.), neither its depression, its elevation, nor even its entire removal have any effect on the voice. Haller (loc. cit. El. Physio. lib. ix. p. 572,) appears also to be of the same opinion: “ Epiglottis equidem nihil faciat ad vocem; cum ea (vox) nata sit et perfecta quam primum ner ex glottidis rima prodiit et absque epiglottide aves suavissime canant. § Fig. 2. 206 Mr. Bishop’s Experimental Researches into cartilages and internal mechanism of the larynx. The mus- cles which elevate the larynx are the Tiyro-, Mylo-, Genio-, and Stylo-Hyoidei, aided by the Digastricz. In this elevation the Genio-glossi, the Lingualis, the Stylo-, Thyro-*, Crico-* Pha- ryngei, and the Hyo-glossz concur. The muscles which have an opposite effect, and Jower the larynx, are the Sterno- Thyroidei, the Sterno-Hyoidci, and the Omo- Hyoidei. . The second set of muscles exerts a very important influence on the voice, the functions of which being imperfectly under- stood will require a few details. The crico-thyroideus + muscle approximates the cricoid to the thyroid cartilage anteriorly, and closes the chink between them ; in this action, the posterior and upper edge of the cri- coid is rotated backwards, by which the antero-posterior di- ameter of the larynx is enlarged, and the tension of the vocal ligaments increased. The crico-arytenoideus posticus { is situated on the posterior broad surface of the cricoid cartilage, from whence it originates. Its fibres, ascending obliquely outwards, are attached to the base of the cricoid cartilage, between the crico-arytenoideus lateralis and the arytenoideus obliquus and transversus. ‘This muscle, by drawing the arytenoid cartilage backwards and rotating it outwards, opens the aperture of the glottis. The crico-arytenoideus lateralis assists in closing the glottis. The peculiarity of the action of this muscle is, that by draw- ing the external angular base of the arytenoid cartilage for- wards, its anterior pyramidal projection, to which the vocal cords are attached, is at the same time rotated inwards. The thyro-arytenoideus is the most complicated, most im- portant, and the least understood of any of the whole set. It forms the whole superior and inferior lateral boundary of the glottis, and is closely connected with the vocal ligaments ; its direct force is to antagonize the crico-thyroideus, to rotate the cricoid on the thyroid, and to draw forwards and approximate the arytenoids anteriorly, as likewise to relax the vocal liga- ments. ‘The thickness of this muscle being increased and ro- tated upon itself inwards when contracting, forces the edges of the glottis together at its central part. By the various mo- tions of the thyro-arytenoidei muscles on the vocal ligaments their edges are turned into the vibrating position, and by their action, in conjunction with that of their antagonists the crico- thyroidei, the tension, and the vibrating length of the glottis are * Names given to some fibres of the Constrictor Pharyngeus inferior. t Fig. 7. t Fig. 2. the Physiology of the Human Voice. 207 regulated. The ¢hyro-arytenoideus superior serves to assist the thyro-arytenoideus in relaxing the vocal ligaments. The arytenoideus obliquus and aryt. transversus* are muscular bands situated between the two arytenoid cartilages, to which they are attached. Some of the fibres assume a horizontal, others an oblique course, and their united action is to bring these cartilages towards each other, by which the aperture of the glottis is closed posteriorly. It is commonly stated in anatomical works that these small muscles are capable of closing the glottis, but this is incorrect. The larynex is lined throughout by a mucous membrane, which being continued from the mouth, over the epiglottis, forms in its descent those folds over the superior margin of the thyro-arytenoide: muscles to which anatomists have given the name of pseudo-glottis; thence swelling out into a pouch of considerable size, it forms on either side the ventricle, or sacculus laryngis+; and finally, after having been reflected over the chorde vocales, it passes through the cricoid cartilage and becomes the membrane of the trachea. A number of mucous glands are situated in the folds of the pseudo-glottis and in the triangular space at the base of the epiglottis, their excretory ducts opening on that fibro-cartilage. These glands doubtless assist in lubricating the vocal canal. The thyroid gland, a singular substance so named (but in which no excretory duct has been discovered), is placed on the larynx and superior part of the trachea; it is composed of two lateral pyramidal portions, united in most subjects by a distinct glandular medium. The size of this gland varies in different individuals; it is said to be larger in the female than in the male. It has generally been supposd by anatomists that this gland has some influence on the voice, but its true func- tions are unknown ¢. The exquisite sensibility of the larynx, its dependence on the will, as well as its muscular motions, are derived from the superior and recurrent laryngeal filaments of the pneumo-gastric nerves. The distribution of these nerves to the muscles which act on the glottis is a subject of anatomical controversy. Experi- ments made on them by Martin||, Professor Sue of Paris, Dr. * Fig. 3. + The sacculus laryngis insulates superiorly the vocal ligaments. t It appears to me by no means impossible that the thyroid gland secretes a fluid transmitted by an invisible process which lubricates the vocal tube. The constant passage of air must render it requisite to be kept permanently moistened, || Edinburgh Essays. 208 Mr. Bishop’s Experimental Researches onthe Human Foice. Haighton *, Cruikshanks, Scarpa, Arneman, Magendie, and others have been attended with curious results. The description given of them by the latter however is opposed by Rudolphi, Andersch, Scemmerring, Meckel, Bellengeri and others. The truth is, that the superior and recurrent nerves anasto- mose in giving filaments to some of those muscles which di- late, as well as to those which close the glottis. The action of these muscles may be briefly recapitulated as follows: The crico-arytenoidei postict open the glottis. All the other muscles close it. The arytencideus obliquus and aryt. transversus close the arytenoid cartilages posteriorly. The crico-arytenoidei lateralis and the thyro-arytenoidei close them anteriorly. The thyro-arytenoide; close the centre of the glottis, and with the crico-thyroidei, regulate its tension, position, and vi- brating length. The views here taken of the actions of these muscles differ from those entertained respecting them by anatomical authors in general. Not having found any two anatomists strictly agreeing on the subject, I have been induced to make numerous dissec- tions to ascertain their functions in producing voice. The annexed figures were drawn by Mr. Henry Dayman, from these dissections. The actions assigned to the thyro-arytenoidet admit of most discussion. That these muscles relax the vocal ligaments, and at the same time close the glottis, may at first sight appear exceed- ingly doubtful; but all my attempts to close the glottis by the approximation of the arytenoid cartilages and the tension of the ¢hyroidei muscles were unsuccessful, nor could any sound be produced until the ¢hyroidei were brought into action, ex- cept by forcing such a volume of air through the glottis as it is almost impossible can take place during life +. In confirmation of this view, it is observed by M. Magendie, * Mem. of the Med. Soc. London. + The quantity of air expelled to produce voice of ordinary intensity is about twenty-five cubic inches in the adult male, with a voice pitched in the tenor G. To produce its grave octave of the same intensity will re- quire 50 cubic inches. In ten seconds therefore the lungs will be almost ex- hausted in producing the upper G, and in five seconds for the grave octave ; allowing 200 cubic inches to be expelled, which is the average quantity of air the lungs are estimated’to contain after a full inspiration. i The quantity of air expelled from the lungs will consequently vary with every note in the scale relatively with the key and the intensity of tone. Mr. Woolhouse’s Reply to Prof. Young. 209 that if the thyro-arytenoidei are paralysed or their nerves di- vided, the vocal chords will no longer vibrate. Although there is a great diversity of opinion respecting the actions of the other muscles, they may nevertheless be easily demonstrated on mechanical principles, which has been partly accomplished by Mr. Willis. In reference to their functions, the vocal organs may be re- garded as a wind instrument, of which the lungs are the bel- lows, the vocal tube the pipe, and the glottis, composed of elastic vibrating membranes, is the reed. The type of these organs is found in all the higher classes _ of vertebrated animals, in mammalia, in birds, and in reptiles. In fishes it may be considered as rudimental. The production of the most simple tone of voice requires the associated actions of a most extensive range of organs *, of which the following is a brief exposition. When the tension of the thyro-arytenoid ligaments takes place they turn upon their axes; their planes (which in a state of relaxation are parallel + to the axis of the vocal tube) become perpendicular { to it, and as the edges of the glottis approxi- mate, its chink is closed up and acquires its true vibrating po- sition §. [To be continued.] XLIII. Reply to Professor Young’s concluding Remarks on the Theory of Vanishing Fractions. By W. 8S. B. Wootuovst.|| N my last paper, on the theory of vanishing fractions, (p. 18,) I have discussed the subject so fully and set forth so many plain and straightforward mathematical arguments, completely proving the truth of the general principles objected to by Pro- fessor Young, that I conceive it would be quite superfluous to make any further addition to what has been already so clearly and satisfactorily established. Professor Young’s concluding remarks on the theory of vanishing fractions are, however, of so unrestrained ‘and extravagant a nature that I cannot possibly allow them to pass without some notice. His observation that the expres- 2 : x sion — Cct— implies an operation to be performed, and that * In the ordinary modulations of the voice more than one hundred mus- cles are brought into action at the same time. t Fig. 4. t This state of the thyro-arytenoid ligaments is the vocalizing position of Mr. Willis: they will not however vibrate unless their edges (through the medium of the mucous membrane) be approximated, and when thus ad- justed, they are in the state which I have denominated the true vibrating position of the glottis. Fig. 6. || Communicated by the Author. hird Series. Vol. 9. No. 53. Sept. 1836. 2A 210 Mr. Woolhouse’s Reply to Prof. Young’s its value is x + a', is in my opinion totally without meaning. Any person possessing a slight acquaintance with the common definitions of plain algebra needs not to be told that the ex- pression x + aimplies an ** operation to be performed” just as 2 —— or . ze and that the expressions are, 2 . x much as the expression = every one of them, “symbolical forms.” ‘The fact is that the 2 2 equation, age = wx + a, simply indicates a transformation of one symbolical form into another, by the operation of divi- sion; and I have distinctly shown that this operation is not justifiable when 2 is equal to a, as indeed Professor Young ; : i eakl Nal: tacitly admits when he speaks of the form 7 isolated or detached from its interpretation. I hold that the questions, 2” — a ; ae when w= a? and What is the What is the value of 2 2 a a . 4s value of aaa ? are not “ perfectly distinct” unless the con- dition of continuity be expressly introduced. In the case x= @ the operation of division by zero is actually performed in the above equation, and yet Professor Young pertinaciously asserts, with an undignified attempt at sarcasm, that he has ‘never seen” any work in which the zero processes occur: the objec- tionable process occurs in every example that he has adduced ; and [ am persuaded that he would not, in candour, have insisted on the problem of Clairaut, or indeed on any other example, as an obstacle to my principles, had he attentively considered my general reasoning at the bottom of page 24 of this volume. With respect to this problem I shall refer to Spiller’s very neat translation of Lacroix’s Algebra, as the more likely to be in the hands of the English student, and just observe that the operations are strict as far as the quadratic root at the top of page 167, but that the succeeding operation in which the numerator and denominator of the second of the two fractions contained in the surd are multiplied by 1 — m, is unwarrant- able in the case m= 1. If the surd be expanded as it is im- mediately and legitimately presented by the quadratic, and the value m = 1 substituted, the operation will lead to the proper My ae : , results, viz. Q? e- This will sufficiently account for my having passed over ‘in silence so decided an argument” as wholly inapplicable to the case. Professor Young refers particularly to the examples in Bourdon’s Algebra, see page 118, fourth edition, where Bourdon deduces the symbols of his results from the general Remarks on the Theory of Vanishing Fractions. 211 formula on page 106. Now in all these examples the factors bc! — cb", bc! — cb, are each zero, and therefore in finding the value of x from the equations (4), (5), page 105, where multiplications are directly performed by these factors, the ob- jectionable zero process actually occurs. Let any one follow the steps of the general elimination, page 105, with one of the particular examples, and the fallacy will immediately present itself. It is the direct incorporation of these foreign ? o , zero factors that gives to the results the form ai which they would not otherwise assume; and they furnish Professor Young with another example of the zero processes which he has ‘* never seen.” The expulsion of foreign zero factors, which are usually in- troduced in an investigation by direct multiplication, is the object of my fourth proposition. If they were allowed to enter, “V6 . : . oO as legitimate factors, in mathematical reasonings, the form Si might very evidently represent any species of quantity whatever. The remarks of Bourdon on this symbol do not refer to what it strictly represents, but only to its general indication, consi- dering all cases without any regard to the legitimacy of the process. What Professor Young states respecting the foreign factors is altogether foreign to the subject in dispute, as the general principles maintained in my essay expressly object to the introduction of all such factors. The real statement of the question is this: Is the value of a vanishing fraction indetermi- nate or not when the zero factors, as in the ellipse question, are not directly introduced, but arise spontaneously in the investigation? and I have thoroughly discussed it in my former papers. Professor Young’s remarks concerning multiple solutions, or what ought to have been properly termed indeterminate solutions, is a mere quibble about words. I must. frankly confess that his important distinction between the two state- ments is one in which I cannot perceive the slightest difference in substance. It would be an idle waste of words to say any- thing more about it. His observations on singular solutions, however, call for some remark. No objection whatever has been offered to the statement which he defends so cavalierly in his present letter. It must be highly amusing to the readers to perceive him calling on the aid of Lagrange in support of a statement that no one, for aught I know, ever thought of disputing. ‘The true state of the case is as follows. Speaking of the result of'a general investigation furnishing every solution to a problem, in his last letter he alluded to the well-known fact of singular solutions not being comprised in the general 2A2 212 Dr. Hare on the Difference between integral, as a decided denial of my statement. In my reply I observed that a direct process of integration always leads to the singular solution at the same time with the general solu- tion, thereby showing that the general result of the investiga- tion does really furnish every possible solution in accordance with what [ had said. Is it not, then, evident that the subject of singular solutions was utterly useless as an objection to my remark, that Professor Young had not sufficiently examined the matter, and that his expression, that I had done myself a “wanton injustice,” was not justifiable on the score either of accuracy or of propriety ? I hereby close my remarks on this subject for the present. It is obvious that Professor Young, instead of applying his own mind to the discussion of the points at issue, has all along rested his evidence and opinions on a misinterpretation of au- thorities. I do not suppose I should have written these brief and concluding observations for the readers of the Journal, had I not felt myself imperatively called upon to notice the tone of assumption and dictation that prevails throughout his last let- ter. He ought not to be unconscious of the fact, that personal sarcasms and presumptuous language are not the generally received indications of a strong supply of argument or of a sincere desire after the development of truth. London, August 13, 1836. XLIV. An Examination of the Question, whether the Discor- dancy between the Characteristics of Mechanical Electricity, and the Galvanic or Voltaic Fluid, can arise from Difference of Intensity and Quantity ; with some Observations in Favour of the Existence of an Electro-motive Power independently of Chemical Reaction, but cooperating therewith : respectfully submitted to the British Association for the Advancement of Science. By R. Hare, M.D., Professor of Chemistry in the University of Pennsylvania.* ]N one of the papers, giving an account of Faraday’s recent valuable researches in electricity, for copies of which I have been indebted to the flattering attention of the author, I find the following language: ‘* Hence arises still further confirmation, if any were re- quired, of the identity of common and voltaic electricity ; and that the differences of intensity and quantity are quite sufficient to account for what were supposed to be their distinctive quali- tiest.” And elsewhere referring to Cavendish, as the author of this opinion, it is alleged that it ‘only requires to be un- * Reprinted from a pamphlet privately circulated by the Author. t [See Lond. and Edinb, Phil. Mag., vol. iii. p. 363.—Enrr. } Mechanical and Galvanic Electricity. 213 derstood in order to be admitted.’ Notwithstanding that in support of the opinion thus quoted, the much-respected au- thority of both Cavendish and Faraday is arrayed, it is one which I cannot so understand as to admit. Iam unable to form any other idea of intensity, than that of the ratio of quantity to space. Thus the intensity of the pressure of an elastic fluid, is as the quantity to the space in which it is confined. ‘The space being the same, the intensity of the pressure will be directly as the quantity ; the quantity being constant, the pressure will be inversely as the space. Agreeably to an analogous mode of reasoning, the intensity of the light or the heat emanating from a radiant body, is al- ways estimated to be inversely as the surfaces on which it may be diffused or concentrated; and hence the inference that the intensity is as the square of the distance inversely, or as the area of the receiving surface of a lens or mirror, to that of the focus into which the rays are collected. It follows that if there be in any two cases, like quantities of electricity evolved by mechanical, and by galvanic appa- ratus, the space occupied by the fluid generated by the latter, must be as much greater, as its intensity is less. In a memoir which I published upon this subject some years ago, I endeavoured to show that the spaces occupied by equivalent charges of galvanic and mechanical electricity were not such as to justify the idea that the former required for its existence a larger space than the latter. But on this subject, it is not now necessary to recur to the facts which I then ad- duced, since I find it conceded in one of the recent Memoirs of Faraday, that the spaces occupied by the electricity evolved by galvanic apparatus, as compared with those occupied by mechanical electricity, are almost infinitely small. ‘* A grain of water or of zinc, contains as much of the electric fluid as would supply eight hundred thousand charges of a battery con- taining a coated surface of fifteen hundred square inches.” ** Four grains of zinc, with one of water, may yield as much electricity as is evolved during a thunder storm.” It follows inevitably that the electric matter evolved by galvanic action is, previous to its evolution, in a state almost infinitely intense, as compared with that of the same matter, when evolved by a machine or meteorological changes. Yet to the currents induced in this matter, in the first-mentioned form, an opposite state is ascribed, as respects intensity, to that in which it has previously existed. It may be said with respect to currents, that the space being the same, the intensity will not only be directly as the quantity, but also inversely as the time in which it passes, or, in other 214 Dr. Hare on the Difference between words, directly as the velocity. But what is to create inequality of velocity when the channel, a wire for instance, is of the same size and nature in both cases? When the same fluid is in question, the velocity will be as the forces by which it may be impelled. The only forces to which electricity has ever been alleged to be liable, as far as I am informed, are either the self-attractive or self-repulsive power of its own particles, or their attraction for other matter. It will be admitted that the intensity of these forces must, in the case of electricity, as in that of caloric or light, be as the quantity to the containing space; and consequently, that it would be unreasonable to al- lege that the reciprocal repulsion of the electric atoms, or their attraction for other matter, and consequently any velocity thence arising, should not be in proportion to the state of con- densation from which they may be liberated. If the superior velocity displayed by electricity generated by friction be the cause, not the consequence of greater intensity, how are we to account for the superior velocity ? According to the doctrine of Du Fay, electricity is retained upon the surface of a charged pane by the reciprocal attraction of the heterogeneous fluids. According to the Franklinian doctrine it is retained by its attraction for the negative surface, on which side this attraction is not counterbalanced by repul- sion from other electricity. When the circuit is completed by a conductor, according to the one doctrine, a surcharge on the one side is translated to the other; while, according to the other doctrine, two heterogeneous fluids rush from the surfaces in which they are previously accumulated in excess, to enter into combination, and, at the same time, to restore the equili- brium of the surfaces on which they have been respectively de- ficient. But according to either hypothesis, wherefore should the forces be greater for electric matter when generated by one means, than when produced by another? Why should amass of electric matter evolved in a diffuse state by a machine, or from a cloud, rush like a bullet through conductors, which are almost impassable to the same fluid when evolved from a state of extreme density within a simple galvanic circuit ? During the process of exciting an electric battery, the elec- tricity previously existing equally on both sides of the glass is so transferred from one side to the other, that the one be- comes as much negative as the other becomes positive; and it must be evident that the intensity will be limited by the extent of the force by which this transfer is effected. It is difficult to conceive that merely by a change of capacity arising from fric- tion, a force should be generated at all comparable to that which the electric matter must exert, in escaping, according Mechanical and Galvanic Electricity. 215 to the premises, from a state of extreme density, as when ex- tricated by galvanic action from water or zinc. I ascertained, some years ago, that the galvanic fluid evolved ‘by a large calorimotor of a single pair, will not ignite a wire which may be easily deflagrated by a much smaller apparatus of the same construction. Yet sheets of metal, about four inches in breadth, might be raised by a discharge from the larger instrument above the temperature of boiling water. In such cases, agreeably to the doctrine of quantity and intensity, the electric fluid exists, up to the period of its evolution, in a state of extreme condensation and consequent intensity, and yet at the moment when a perfect but restricted channel is afforded to it, becomes too diffuse to pass through it with a velocity suf ficient to produce deflagration. How can the electricity which is in the one case so dense, become in the other so rare? Where, and in what manner does it exist intermediately be- tween the period of its condensation within the pores of the generating materials, and its rarefaction in the wire which forms the circuit between them ? I am aware that to the want of adequate insulation, the in- ferior intensity of the charges communicated to coated surfaces by voltaic apparatus, will be attributed ; as it cannot, without a palpable contradiction, be ascribed to any defect of intensity, in a source wherein the ratio of the quantity to the space is almost infinitely great. Let us, then, examine the subject agreeably to this view of the case. Since the electricity liberated by electro-chemical reaction by means of a single galvanic pair must have pre- existed in a state of extreme condensation and consequent in- tensity, it follows that it ought to be productive of a tension limited only by the insulating power of the menstruum within which it is extricated. It should then, when evolved as above described, attain the highest degree of intensity consistent with the insulating power alluded to. That this is not the fact, is fully established by general experience, and by the observations of Faraday, according to which the intensity of a voltaic series increases with the number of pairs employed. It results also from the premises, that the tension should be- come as great in a large as in a small pair; and by employing one large pair, effects should be attainable, as potent in respect to intensity, and more potent as respects quantity, than those resulting from a series of pairs. Yet the experiments above mentioned prove, that as the surfaces, associated as a single galvanic pair, are enlarged, the intensity lessens; so that a ca- lorimotor of a single pair containing fifty square feet of zinc, will not, in a wire of any size, produce an ignition of as high 216 Dr. Hare on the Difference between intensity as may be effected by the elementary battery of Wol- laston, formed of a silver thimble, and piece of zinc propor- tionably minute. It appears from the experiments of Professors W. B. and H. D. Rogers *, that the power of a galvanic pair in deflecting a magnetic needle, was increased by causing the surface of the copper plate to exceed that of the zinc; while by extending the zinc surface beyond that of the copper, little or no increase of ower ensued. This result appears to be the opposite of that which the theory of Wollaston, supported by some recent ob- servations of Faraday, would lead us to expect. As pursuant to that theory, the galvano-electric fluid is due exclusively to chemical reaction; if the charge were not promoted by an ex- cess of extension in the oxidizable metal, it ought not to have been improved by similar extension of that which is insuscep- tible of oxidizement. According to the observations of the Professors above men- tioned, the deflection resulting from a galvanic discharge, on the first immersion of the plates, after a repose of two hours, was six times as great as that which could be permanently sus- tained. The greatest effect appeared always to ensue before there was any sensible extrication of hydrogen, and the com- mencement of the effervescence was invariably the signal for a decline of power. It was by analogous observations respecting the igniting in- fluence of galvanic apparatus that I was led to the construction of my deflagratorst, in which the deflagrating power appears, agreeably to my experience, to be exalted as much by the re- pose of the surfaces as the ability to influence the magnetic needle was ascertained to be, in the experiments of my saga- cious friends above mentioned. That the evolution of the galvanic fluid is not in proportion to the intensity of the chemical reaction, is corroborated by the fact, that the intensity of the ignition, excited in a wire by a galvanic discharge, diminishes, while the effervescence in- creases; and it is well known that the power of galvanic ap- paratus is not augmented by adding to the strength of the sol- vent, beyond a very moderate limit. But if it be granted that chemical affinity, when reacting within a galvanic circuit, without any propulsive power from the elements of the circuit, can receive a peculiar impulse, so as to produce a current of the electric fluid, confining it at the same time to a very narrow channel, by what process can this species of chemical reaction be conceived to accelerate an elec- ® See Silliman’s Journal for October, 1834. + [See Phil. Mag., First Series, vol. lvii, p. 281, lix. p. 113, & Ixiii. p. 241. —Enpit. | Mechanical and Galvanic Electricity. 217 trical current already produced? The same propulsion must be given to the electricity liberated between the plates of the second pair as between those of the first; and it is inconceivable to me, that the accession of that derived from the first pair should add to the velocity of the portion evolved by the second. The current of the former cannot be supposed to move with greater velocity on account of its meeting with another, which moves at its own rate. Currents are not accelerated by their confluence, unless the head or pressure be increased, and the channel restricted. But in the case in point it has been shown, that by the reaction of the solvent with the first pair in the se- ries, the tension must attain the highest degree consistent with the imperfect insulation; and no cause has been assigned for the restriction of the channel. It may be said that the current from the first pair cannot pass through the liquid in the second cell without causing the decomposition of that liquid ; and that as its power is inadequate to effect this change, it has to pur- sue the same route as the electricity which is generated by the oxidizement of the second plate of zinc. It is still difficult to me to imagine that it can transfer its momentum to the cur- rent which thus precedes it; or that the chemical reaction by which the latter is evolved, should act only in accelerating the stream which it receives from the preceding pair. Granting that imponderable matter, at the moment of its extrication from confinement among ponderable atoms, were to receive an impulse which, by extraneous cooperating causes, should force it to move in a current, yet I cannot imagine that such atoms can, by any reaction originating between themselves, give an impulse to imponderable matter extricated from other atoms. Whether or not the electricity be derived from chemical reac- tion, it seems to me that the power which puts it in motion, and accelerates and condenses it into a channel, still smaller and smaller as its intensity increases, must be ascribed to some mysterious property arising from the arrangement of the ele- ments of the series, which is, in the present state of our know- ledge, inexplicable. This electromotive power, if not antecedent, does not ap- pear to me to be consequent to chemical reaction. I conceive that it operates upon all the imponderable elements within its scope, tending to accumulate them at the “electrodes” under a greater or less degree of tension. The potency of the re- sulting discharge, when the circuit is completed, is regulated both by the tension and the quantity of the imponderable mat- ter accumulated. But the presence of reagents, which favour the extrication of imponderable materials, as in the more effi- cient voltaic apparatus, is compatible only with a feeble insu- Third Series. Vol. 9. No. 53. Sept. 1836. 2B 218 Dr. Hare on the Difference between lation, while arrangements more favourable to insulation, as in De Luc’s Electric Column, are incompatible with a copious supply of the imponderable matter. Probably upon an analogous ability to produce or annul, to promote or retard, chemical reaction, the efficacy of animal and vegetable organization is founded, being obviously depen- dent on an arrangement of masses. ‘The voltaic series of a gymnotus is evidently an animal organ, and its analogy with the voltaic series produced by human ingenuity induces me to consider the latter in the same class of agents as the organs by which life is supported. I should have expected, that in establishing the highly inter- esting fact that every elementary equivalent has the same quantity of electricity, the ingenious author of this discovery would have adverted to the analogous observations of Petit and Dulong respecting the specific heat of elementary atoms. It strikes me as important, that similar conclusions should have been arrived at by such high authority, both as respects caloric and the electric fluid. 1am surprised that Faraday should appear to have overlooked this analogy in the explanation of the practical results which he has obtained. No hypothesis appears to be more generally sanctioned at this time among chemists than that which ascribes the aeriform state to a union between caloric and ponderable matter. When hydrogen unites with oxygen, caloric is evolved. It follows that when these substances are made to resume the gaseous form, caloric must be supplied to them. When it is considered that the inferences of Petit and ‘Du- long, respecting the specific caloric, and those of Faraday re- specting the electricity combined with ponderable equivalents, tend to demonstrate the coexistence in them of equivalent at- mospheres of each of those imponderable fluids, does it not authorize a surmise that in the voltaic current they may be associated ; and that with those equivalent measures of elec- tricity which Faraday has shown to pass, corresponding por- tions of caloric are imparted? ‘The idea of Berzelius, ‘that the heat and light evolved during powerful combinations, are in consequence of an electric discharge at the same moment taking place,” being cited by Faraday in the language of this quota- tion, he observes, that it ‘is strictly in accordance with his view of the quantity of electricity associated with the particles of matter.” To me it appears to be no less in accordance with the idea that heat and light are associated with those atoms to a commensurate extent; and since, by the premises, electricity reacts with them, they may be presumed to react with electricity. Mechanical and Galvanic Electricity. * . B19 That heat, light, and electricity are all concomitant pro- ducts of electro-chemical reaction, is self-evident. Agreeably, then, to the strict rules of induction, wherefore is the principle last mentioned to be considered as the cause of the others? Where is the proof that the heat and light evolved between the “electrodes” are effects merely of electricity? The fact of the apparently unlimited evolution of heat from a finite portion of wire duly subjected to a voltaic circuit, is inexplicable, con- sistently with the materiality of caloric, unless we suppose the fluid to be derived from the same electro-chemical reaction to which we owe the electricity associated therewith. I conceive it to be almost self-evident, that mechanical and voltaic electricity are due to the same fluid, so far as they are strictly electrical. ‘The only doubt with me is, whether the very different characteristics of the pheenomena produced by the different means alluded to could be explained without sup- posing some other modifying causes. And atall events, from the reasons above given, I am dissatisfied with the explanation that the difference is dependent on quantity and intensity. In terminating my observations, I subjoin the following statement of my opinions as heretofore expressed in one of my text-books. “‘It does not appear to me that the production of electro- magnetic phenomena, both by galvanic and by electrical dis- charges, disproves my opinion, that caloric and electricity are connate and coordinate products of galvanic action. As ignition is producible by either discharge, whether elec- tric or galvanic, the fluid of heat, no less than the electric fluid, may in both cases be concerned; and it is yet to be shown, that magnetic phenomena are ever due to the unalloyed agency of electricity. It is true that magnetism has been imparted, by discharges of mechanical electricity, without any ostensible agency of ca- loric ; but it is equally true, that magnetic movements have been produced also, by the application of heat, unaccompanied by any ostensible agency of the electric fluid; and it seems as ra- tional to suppose that caloric and electricity are associated in the first instance as in the last. Those who consider electricity, varying in quantity and in- tensity, as the common cause of electrical and galvanic ignition, and of thermo-magnetic phenomena, must suppose that this principle and caloric are capable of a reciprocal action. In the first case, caloric is evolved by electric action ; in the last, electric currents are produced by calorific repulsion. Hence, as action and reaction are equal and contrary, I deem it ra- tional to suppose that in some a the former, in other cases 2b2 220 Mr. Rainey on the Attractive Power of Magnets, the latter, may be the prime mover; but that both participate in every galvanic, electro-magnetic, or thermo-magnetic cur- rent. XLV. On the Difference between the Attractive Powers for soft Tron of the Electro-magnet and the Steel Magnet ; in reply to Dr. Ritchie. By G. Rainey, Member of the Royal College of Surgeons. To the Editors of the Philosophical Magazine and Journal. GENTLEMEN, fs Rt last Number of the Philosophical Magazine, at page 83, contains some remarks by Dr. Ritchie upon a paper which I communicated in May last (printed in the Number for July), concerning the cause of the great disproportion in the attrac- tive power of the electro-magnet for soft iron when in contact and at a distance, compared with the attractive power of the common steel magnet under similar circumstances. ‘The con- cluding paragraph of Dr. Ritchie’s paper is as follows: “‘In the explanation given by Mr. Rainey, the lifter is sup- posed to react powerfully on the electro-magnet, so as to in- crease its power, a supposition which cannot possiBLy be ad- mitted. For the electro-magnet must, in the first place, give the lifter all its magnetic power, consequently the power of the lifter can never exceed that of the electro-magnet, and conse- quently never can induce a higher magnetic state in it than what has already been done by the voltaic helix.” What Dr. Ritchie pronounces to be a supposition which cannot possibly be ad- mitted, I will prove, I think to Dr. Ritchie’s satisfaction, both by reasoning and experiment, to be an absolute.and undeniable fact. My position is, that the lifter of a common horse-shoe magnet can exceed the power of the magnet to which it is ap- plied; and in case that magnet has not received its maximum of magnetism, can induce in it a higher state of magnetism than that which existed before the application of the lifter ; and that in proportion as the permanent magnet resembles in its texture soft iron, the effects of induction on it and on the electro-magnet more closely resemble each other, so as to render it obvious that the effect of the keeper on the two is the same, excepting in degree. Let a and } denote the inducing power of the magnet A, and let B be a piece of soft iron, placed in the position represented in the annexed diagram, and sufliciently large to receive all in reply to the Rev. Dr. Ritchie. 221 the magnetism S is capable of inducing. It is evident that a will represent the mag- netism induced at the adjacent end of the soft iron, and d that at the remote one: now in this position of the soft iron B can have no more magnetism than it receives from S; consequently, cannot exceed the power of the magnet A, and therefore cannot in- duce in it a higher degree of magnetism than it possessed before the contact of B. So far Dr. Ritchie’s assertion holds good ; but the circumstances are very different under which the armature is placed in the electro-magnet, or the common horse-shoe magnet referred to in my paper. , Now let B be placed, with its extremities in contact wit both poles of the magnet A; then, according to the first case, a will represent the magnetism at the S pole, and 6 that at the N pole; but as S has induced in B a + 6 of magnetism, so N must induce in B 4 + a of magnetism; therefore 2 a will now represent the magnetism at the S pole, and 2 6 that at the N pole. According to this reasoning, the contact of the armature should tend to induce a + 6 of magnetism in the magnet A, provided A has not received its maximum of magnetism, or is not too hard to admit of further induction by the reaction of the keeper. This is exactly what occurs, which will be manifest from the following experiment. Take a common horse-shoe mag- net, magnetized in the ordinary manner; then weaken this magnet by gliding repeatedly the armature from the poles to the neutral point: this mode of reducing the power of a mag- net is much better than by applying its poles to the similar poles of another magnet, as it does not alter the disposition of the magnetism in the metal; consequently the position of the neutral point remains in the centre. The magnet being thus treated, note accurately its magnetic power ; then apply a piece of soft iron to its poles, in the manner in which the lifter is em- ployed in the electro-magnet ; and after the removal of the soft iron, the magnet will be found to have acquired a considerable increase of magnetic power. Ifthe lifter be slided from the neu- tral point to the poles, its reaction will have been exerted more generally upon the steel, and the magnetism induced by the keeper will consequently be increased. By performing these experiments upon magnets composed of steel of different de- grees of hardness, it will be found that the softer the steel is the greater will be the increase of the magnetism it acquires Te 222 The Rev. Dr. Ritchie’s Remarks on certain from the reaction of the armature: and the density also of the armature has considerable influence over its inducing power, both on the steel magnet and the electro-magnet; if the arma- ture applied to the electro-magnet be made of very hard steel, it will not sustain so much weight from the same intensity of galvanic current as if it be made of soft iron. Thus it will be obvious that the more the steel is allied to iron in its temper, the more closely the effect of the keeper upon the steel magnet will resemble that upon the electro- magnet. Hence the explanation of the action of the armature upon the one will apply to the other. In order that no misconception of my meaning may take place, I will give one application of the above reasoning to the case of the electro-magnet. Suppose a feeble galvanic current to have been passed around an electro-magnet, and that the magnetism induced by this current is represented by a and b; then, according to the foregoing explanation, 2 a and 2 6 will represent the magnetism on each side of the centre of the ar- mature; and as this exceeds the magnetic power induced by the voltaic helix in the electro-magnet by a + 4, the armature will induce a + 4 of magnetism in the electro-magnet. As soft iron offers so little impediment to the inducing power of the armature, this power may be considered to exert its maxi- mum effect upon very soft iron, and its minimum on the hardest steel: now suppose the electro-magnet to have received an accession of magnetism from a stronger galvanic current, which may be represented by c + d, then the inducing power of the armature will be raised to 2 (b + d) at one extremity, and 2 (a + c) at the other; and the electro-magnet will have now received from the armature c + d more of magnetism, and so on for all future additions of magnetism induced by the voltaic helix, until the electro-magnet has attained the highest state of magnetism it is capable of. XLVI. Remarks on certain proposed Improvements in the Magneto-Electric Machine. By the Rev. W1111aM Rircuie, LL.D., F.R.S., Professor of Natural Philosophy in the Royal Institution of Great Britain and in the University of London. -E the last Number of the Philosophical Magazine, p.120, there is a paper on Magneto-electric Machines, by Fred. Mullins, Esq., M.P., of such an extraordinary nature, that I feel my- self called upon to point out its fallacy and inconsistency. As Jacts are by far the most stubborn things to get rid of, I shall simply state two experiments, which will be quite sufficient, without entering at all into the principles of the science. proposed Improvements in the Magneto-electric Machine. 223 Experiment 1. ‘Take two bars of soft steel of any convenient size, cut one of them in the middle, and bend the other into the form of a horse-shoe magnet; temper both to the same colour, magnetize them equally, and try their powers in the following manner: bring the two bars, as in the figure, to different di- stances from the lifter A B, and ascertain their attractive power ; remove the bars and substitute the horse-shoe, and its power of attraction, and consequently its inducing power, will be found to Ss N be much superior. Place the bars and horse-shoe in succession at the same distance from a revolving lifter, and the electricity induced on the coil will be found to be much greater, both in deflecting a needle and in decomposing water, with the horse-shoe magnet than with the equal bars. Hence the absurdity of using bar magnets instead of horse- shoe ones to z2duce magnetism on soft iron, and thence voltaic electricity on a coil. Experiment 2. Cut a bar of the same length as before into three portions, bend one of the pieces into an arc, magnetize the two parts, apply the arc to form a horse-shoe magnet as Mr. Mullins proposes, repeat the previous experiment, and the old horse-shoe magnet will be found to be much stronger than the new one. It is easy to see how Mr. Mullins, in his experimental re- searches, has been led into these errors. Horse-shoe mag- nets, made by ignorant makers, are often left almost entirely soft at the bending and only hardened towards the poles or ends, from the old absurd notion that the magnetism was accumu- lated at the poles. ‘The soft part of the circuit therefore, possessing scarcely any coercitive power, is very much in the same state with a piece of soft iron. Such a magnet may per- haps be improved by cutting off the bending and supplying its place by a properly magnetized arc. Another error into which Mr. Mullins has fallen is not so easily accounted for : he affirms that the size of the arc is of no consequence. A tempered steel wire would therefore be as good as an arc formed of steel, two inches broad and half an inch thick. In- stead then of recommending gentlemen who have horse-shoe magnets applied to magtieto-electric machines, to cut off the bending, the wisest course will be to let them alone if they are properly tempered, if not, to get them re-tempered and re- magnetized. XLVII. Proceedings of Learned Societies. ZOOLOGICAL SOCIETY. Feb. 9, i [ieee reading was concluded of a paper ‘‘ On the Ana- 1986. 5. tomy of the Lamellibranchiate Conchiferous Animals, by Robert Garner, Esq., F.L.S.,” a portion of which had been read at the meeting on November 24, 1835. Founded principally on the author’s individual observations, which have extended to the animals of several genera the anatomi- eal structure of which is hitherto insufficiently known, this commu- nication embodies also much information derived from the works of Poli, Cuvier, Bojanus, Home, M. de Blainville, and others. It is so arranged as to constitute a condensed memoir on the subjectto which it is devoted, comprehending a summary of all that is yet known respecting it. After some general remarks on the high importance of a know- ledge of the structure of the animals that form those shells which have at all times attracted the attention of the curious, but to an acquaintance with which many naturalists, until of late years, have been content to limit themselves, Mr. Garner proceeds to speak of the position of the animal with respect to the shell; and thence to describe the variations in the form of the animal which occasion those appearances in the shell on which rest the primary subdivisions made by conchologists among the Lamellibranchiate Conchifera. He regards Anomia as being in some measure intermediate between this order and the Brachiopoda ; and in illustration of this view describes with some detail the structure of the animal of that genus. Mr. Garner then adverts to the mode of growth of the shells and to their structure, and considers them in the variations in form which some of them undergo in their progress from the embryo to the adult state. He dwells also on the diversity of form assumed by the several groups of Bivalves, and shows in what manner these are occasioned by the form of the animal that produces the shelly cover- ings; referring to the foot especially as exercising in this respect a very remarkable influence. The general review of the external form of the animal is succeeded by an account of the several systems of which it iscomposed. ‘These are treated of in the following order: 1. Muscular system; 2. Ner- yous system; 3. Digestive system ; 4. Circulating system ; 5. Respi- ratory system; 6. Excretory system; 7. Cilia (and into this part of his subject the author enters with more than usual detail) ; and, 8. Reproductive system. Under each of these heads a rapid review is taken of the principal variations that occur in the order, and the illustrative examples referred to are generally numerous. Finally, the author devotes a section of his paper to the diseases and the parasites of the animals on which he treats. Loological Society. 225 In conclusion, Mr. Garner submits the subjoined tabular view of an Anatomical Classification of the LAMELLIBRANCHIATE ConcuHI- FEROUS ANIMALS. With but one adductor muscle. Monomyaria, Lam. Tentacles very long, not distinct from the bran- che ; an additional muscular system........ Anomia. Tentacles short, separate from the branchie. No foots. dchsinceeeiveh Leeks Bae aa 2mOstrea. A foot. Branchie disunited medianly. Foot long, cylindrical ; ocelli at the edge of.tihermantle Vasil ad}. . opent Pecten. Foot short, thick, with a disk at the ex- tremity, from the centre of which depends a pedicellated oval body; GCL os By sak D canis’ a ots Sanco BORE eae Spondylus. Foot compressed ; no ocelli.......... Lima. Branchie conjoined medianly .......... Vulsella.* With two adductor muscles. Dimyarta, Lam. Mantle without separate orifices or tubes. ; Foot slender, byssiferous; tentacles fixed.. 79 6 Limestone, according to Mr. Porter .........-.. 6 Colourediclayst.... ss. - 2: os -- prune sitectustaeis 43 0 Blue clayptts eis sks Cocos moe eo Soe 1 0 SACK iHAES ee wteldoretetsne + tee gs tie the aye? sferelalerareeoevomtaate re etal nO LOTS RSH ANEE A AS OE A. 8G Ge onanad ccrmpbuac eye steete tere Baar O' 6: Blue clay, sometimes changing to red.....---+-.-+++++++- 5 0 Limestone, main seam ..........+.+ Thee has oatiote 9.9 Coloured shaly clays ............s.e9-e05 labia (about) 60 0 Coalie a Aaaooet pelippinckisece ce sts path beats fisie ts sagen Is Coloured clays, extent unknown. On the banks of the Medlock we find the following section exhibited : Ft: , in. Red clays, extent unknown; one thin seam containing Unionide. Eimestone Ais ee doen Ae SCISSOR Sr ar fr 4 0 Red ‘and blite: elaye ogc) eae Bt eh 20 0 Limestone .......++ endie ola oi tat seg em Sipser ea’ PPM Nt ek 3 0 Glanch 36. S35. oo se shenio caiearsrcerns sil doareidanbeast aaotye ea! et iO [Here the section is lost for some feet under the diluvium. | Red sandstone and clunch in thin lamine .............. 10 0 Hard seam of sandstone ..............- dain tes et, 13 Soft red lamellar sandstones..........e0.scceecceeee cece 20 0 Hard grey sandstone ............ alataiele\s/s Moreover, by the resolution of forces, ecu Tey N Re barr ) __ force of gravitation sere. pga) yan normal force But from the well-known theorem of Huygens, the normal 5 v ch : ; force is expressed by Rp? and it is an obvious deduction from the first law of Kepler that the velocity varies inversely as the perpendicular upon the tangent. (Principia, sect. 2, prop.1. cor. 1.) Hence vw C? C? Normal force = R= PPR TN pe etreteesetsees (2+) Consequently (1.) * Communicated by the Author. 334 Mr. Graves’s Explanation of a remarkable Paradox 2 Gravitation = — 72? that is, the attractive force varies inversely as the square of the distance. By substituting for p its value a@ (1—e°) we get the ex- pression usually given in books on physical astronomy. It may be proper to remark that the foregoing proof dif- fers but little in principle from one lately given by M. Tran- son, in the Journal de Mathématiques; but as that is made to depend upon a property involved in the theory of caustics—a subject quite foreign to the inquiry—it is presumed that the process here given will be preferred on the score of elementary simplicity. Belfast, Sept. 26, 1836. LXVI. Explanation of a remarkable Paradox in the Calculus of Functions, noticed by Mr. Babbage. By Joun T. Graves, Esq., M.A., of the Inner Temple.* “pes following passage occurs in a very valuable paper by Mr. Babbage, * On the Analogy between the Calculus of Functions, and other branches of Analysis,” published in the Philosophical Transactions for 1817. (vol. cvii. pp. 211, 212.) «‘ Here perhaps it may not be misplaced to state a diffi- culty of a peculiar nature with respect to functional equations which are impossible; for. the sake of perspicuity I shall con- sider a very simple case, 1 vr = Dh dae (1.) A 1 1 for x substitute ae p = cha (2.) ee oe 1 and by multiplication, ) x xb— =Cbarx A or 1 =’, x from which it follows that c = + 1, or, in other words that Lvs ‘ the equation Pa = cy Pa contradictory, unless c = + 1, Now the functional equation F {2, Pa, baa} = 0 has been reduced by Laplace by means of a very elegant artifice to an equation of finite differences; nor am I aware that this pro- found analyst has pointed out any restriction or any impossi- ble case. If we treat the equation ) x = cw” by his me- thod, we shall find for its solution — log log x oer (3.) * Communicated by the Author. in the Calculus of Functions, noticed by Mr. Babbage. 335 and this solution satisfies the equation ) « = cy 2” independ- ently of any particular value of 7, and if we suppose 7 = —1, —log2 x we have dare Oe ee (4.) : , ] for the solution of the equation Px = cy 2 whatever may be the value of c, and we have before shown that it cannot have a solution unless c = + 1. The only explanation Iam at present able to offer concerning this contradiction is one which | hinted at on a former occasion, viz. that if we sup- pose to represent any inverse operation which admits of several values, then if throughout the whole equation we al- ways take the same root or the same individual value of , it is impossible to satisfy the equation, but if we take one value of & in one part, and another of the values of \ in other parts of the equation, it is possible to fulfill it by such means. This solution may, perhaps, appear unsatisfactory ; it is how- ever only proposed as one that deserves examination, and I shall be happy if its insufficiency shall induce any other per- sen to explain more clearly a very difficult subject.” This passage is referred to by Professor De Morgan in bis article on the Calculus of Functions, §. 72, in the Encyclo- pedia Metropolitana, and I generally agree with him in the cause which he suggests for the explanation of the difficulty, viz. a discontinuity in the form of y, by which I mean that for different sets of continuous values of x, has partial non-con- current solutions of different forms. What I now propose is to point out specifically the existence of that cause in the in- stance put forward by Mr. Babbage, and the precise rationale of its application in explaining the difficulty in question. The accomplishment of these objects, which do not seem to have been hitherto satisfactorily effected, would not only be inter- esting for its own sake, but would, in many analogous cases be conducive to clearness of reasoning, and tend to restore that confidence in the result of mathematical principles which is impaired when processes apparently legitimate lead to con- tradictory conclusions. If, according to the explanation thrown out by Mr. Babbage, (as I understand it) ~a had many values for a given x, and we were allowed to shift its different values among the equations (1.) and (2.), substitut- ing one of those values for the symbol 2 in one part of either of those equations, and another in another, it is easy to see that we might get rid of the difficulty of supposing * = 1, and might even, if we had a sufficiently indeterminate ax, allow toc an infinite number of values. By this plan, for instance, if a had two values, v and v, be might vx 336 Mr. Graves’s Explanation of a remarkable Paradox | v i ; mean < and > well as 1. But I think that, in the first place, such a shifting is not a legitimate proceeding, for the different values of a generic function of w are themselves dif- ferent individual functions of 2, while the equations in question suppose a comparison of the same functions, and are couched in an algebra applying to individual values; and, in the se- cond place, even such an explanation would not succeed in the case before us in wholly removing the real difficulty, for, even by the utmost shifting, we cannot suppose c an entirely arbitrary constant, unless for any given x, th a itself be wholly aii atid arbitrary, which c 18 (-—1) assuredly is not. The true so- lution resembles while it differs from that thrown out by Mr. Babbage, unless (as may possibly be the case) the vague terms he uses are intended to adumbrate the very solution which I contend to be correct. The paradox is occasioned not because wz has different values for one value of a, but because has different forms for different values of 2. Is this so, and, if so, how does it obviate the difficulty? These are the inquiries which it is the design of this paper to answer. At the very threshold of our researches a question that must present itself is, What do we mean when we put } — log? r Ae l = ¢ s(-1), and assert that Pxr=cy v ? Do we mean 21 ig (a ——\" to assert that the expressions c °6(—)) and ¢.cs(—-)) are equivalent generic forms, (like a’ b? and (ab)*) as having each the same infinite number of values for any given x, when we let in all the acknowledged indefiniteness of the notation log 6 and a’? As I presume that such an assertion of general equivalence is not intended, and as it is not necessary for my future argument to deny it now, I shall not stop to prove its incorrectness, but this, at /east, I think we must be supposed to mean, viz. that, for any given within certain limits, the — log? x form c !°s(—1) includes some values or some fixed single value which respectively are or is equal to other severally corresponding values or another corresponding individual value — log? x — log 9 1 _ log?— included in the formc.c !g(—1) . I proceed, therefore, to log? x point out a case of x included in the form c ~ tog(—1), which in the Calculus of Functions, noticed by Mr. Babbage. 337 : ‘ Pie | : satisfies the equation Pa = cy me but I hope to show that “it satisfies that equation only for such values of z as to exclude one of the assumptions we must make if we would prove c?=1,” or that, ‘if it satisfies equation (1.), 2 must be classed with ] : : one set of values, and = With another different set; and further, that if any of the latter set be substituted for x in the — log? r particular case of fz included in c °(—1) which before sa- tisfied (1.), that equation will no longer hold good, so that (2.), which is obtained by substituting = for x in (1.), can- not subsist simultaneously with (1.) for the assigned form of yz.” The instance I shall select will be given as being the simplest illustration I can present of the application of this principle, and as being, morever, independent of any hitherto disputed peculiarities in my results concerning logarithms ;— not that I at all recede from those results, but that I wish to approve my present results to those who are not yet convinced of the former. ‘The same principle may be proved to apply if we select any other individual case of x included in the form log? x e — 'g(—1), which when a is within certain limits, satisfies equation (1.), when c® is not = }. To prevent misconception, it may be as well here to re- mark, that I admit no difference of meaning in result, what- ever difference of intermediate operation may be denoted, be- — log? log? z log? z tween c !08(—1), ¢ log (—1) and ¢ —!6s(—1), and that asa ge- logt x neric form, I consider ¢ °8(—") to be precisely equivalent to — log? « clog(—)) , for if k be a logarithm of —1, so also is —&, Hence both expressions contain exactly the same values, it being remembered that any value common to both corre- sponds to different individualizations of log (—1) in each. The proposed functional solution for ) being included in log? x the form c!°8(—1) Jeads us to consider algebraical symbols as capable of possessing imaginary values, since it involves log (—1), an expression which has no real value. In the pre- sent case we shall see that the discussion of the proposed func- tion of x is cleared from the obscurity that surrounds it when z is real, by our knowledge of its properties when « is infini- Third Series. Vol. 9. No. 55. Nov. 1836. zR 338 Mr. Graves’s Explanation of a remarkable Paradox tesimally imaginary. Though this course may seem to savour of the system “ ignotum per ignotius,” itis no less true than singular that in this instance a difficulty more peculiarly af- fecting reals receives light from the consideration of imagi- naries. ‘To exhibit x therefore in its most general form ad- mitted in algebra, including imaginaries as well as reals, let x=ytV—1s (5.) y and 2, which I call the ‘ constituents” of x, being inde- pendent quantities, positive, negative, or + 0 or —0. Then we shall have 1 y —_ 38 Here it is important to remark that the second constituent of x is always of a different sign from the corresponding con- d 1 : atte z ‘ : stituent of —, for if z be positive, — ——— will be negative, Lx y + 23 and vice versd. I must now lay down some necessary definitions of the no- tation employed, preparatory to the statement of a proposi- tion which will be found further on, and I must here add that, in resorting to a new specificatory or individualizing no- tation, I have unwillingly yielded to necessity, from finding that the indeterminateness of ordinary exponential and in- verse trigonometrical expressions almost always occasioned perplexity and frequently led into material errors of rea- soning ; not that I was unaware of the repugnance which any new notation has to encounter, and the increased difficulties it opposes to the reception of any new theory. Let the sym- bol 4/, placed before a positive quantity, be appropriated to a z : denote the positive square root; then —— will denote 1 or V 2 —1, according as z is positive or negative. When x is real, and therefore z = 0, we have no more right to consider z positive than negative, unless it be known absolutely that the variable z is in such a varying state as to be about to become x+dy+ W/ —1dz, the sign of the real infinitesimal dz being known; but still, when x is real, and nothing else is known with reference to its varying state, this at least we know al- ‘ . . 2s ternatively, that if we consider —— = 1, there would be a V 3 metaphysical impropriety, a wanton violation of analogy and . : ° . . z . @ontinuity, innot considering — —— = —1, and vice wersd. WV 3 in the Calculus of Functions, noticed by Mr. Babbage. 339 When once we introduce into our calculations the considera- tion of imaginary values, we have to treat x ORE Vay = as essentially a variable in both its constituents, and therefore = can never fairly be supposed in the condition of an absolute central stationary zero. Let 7 7 y’ +2 denote the arithme- ON EY es VA x +22 denote the circular arc not less than +0 and not greater than z, which, when radius =1, is equal to poe UM os re V yr +2 bar ott a3 tical Neperian logarithm of V y?+2*. Let COSy vious that such an arc is always assignable, since = V Pte can never be greater than 1, nor less than —1. I come now to the following proposition, before referred to, viz. we 8 5S Polen —1 ¥y Z < “<] VPpsee ig argh a as oa Vets is a Neperian logarithm or e-log of x.’ This proposition is proved in my papers on exponential functions cited in the 8th volume of this Magazine, p. 281, (Number for April 1836) ; but as the heads of the proof are very simple and at the same time illustrate my subsequent reasoning in the present case, I shall briefly recapitulate them here. Let the notation e,’ denote that particular value of the am- biguous expression e’, which is represented by the sum of the 6 on Ea, thee vy) where @ is not limited to real values. It has not been unusual to treat of ¢’ when § is imaginary, and when this has been done, the meaning of e’ must have been tacitly defined (though probably without regard to the possibility of ef having many values for any given 6) by reference to the preceding series, which is convergent for all values of @. A series, when resorted to as a definition is most convenient if always converging, but in development a series is not to be considered as correct and safe merely on account of its convergence, for expressions may be assigned which are developable by some incomplete me- thods in a converging series, and yet may be shown, from the functional properties which constitute their best definition, to be equal to ” terms of such series together with a remainder (sometimes representable in the form of a definite integral,) which, in certain cases, instead of approaching towards 0 as a 2R2 series 6° 1464 aon 340 Mr. Graves’s Explanation of a remarkable Paradox limit like the remainder of the series, recedes from 0 as 7 in- creases. It is demonstrable from the nature of the series (7.), and may, I think, be assumed as an admitted proposition, that gible 2c eo (8.) SUPE Le EEL eae Hence elv ¥tE+/=-1 Se 0+ Syte UiGas abe Re y = 6 VIFF x eM Ve 04 a FEE (9.) Now, of the right-hand member of (9.), the first factor, viz. e,V¥'+* is evidently equal to /y?+2%, and if it can be ES 0+ /y'+2" is cos shown that the other factor, viz. e,” | = Y+V—l1e2 V Pte » our proposition will be proved, for equal to 7 ee ere —1 y it will be proved’ that Pi koe ele a Se on Sete ——, YytVilz a? ; = ie en a EE = y+ V—1z = 2; that is to say, it will be proved thatl 7 y°+24 V%—1 LS Go ee V8 04 V¥YP+2 is an e-log of y+4/—1s or 2, according to the most limited definition I can conceive of the term Neperian logarithm that will extend to imaginaries. if by cos 6 be understood the sum of the series 6? 64 i- e + 1.2.3.4 — &c. (11.) and by sin @ the sum of the series §8 98 oe sera d:aieGibies (12.) This not only follows immediately from the definition above given of the notation ¢,*, but the definitions of cos @ and sin 6 accord with admitted theorems respecting the sine and cosine when @is real. The two series(11.)and (12.)are convergent for all finite values of 6, and I can see no objection to them as defi- nitions of sine and cosine, even when @ is imaginary. I doac- cordingly treat them as such in my general exponential theory, in the Calculus of Functions, noticed by Mr. Babbage. 341 but for our present purpose it is enough that equation (10.) be admitted when 6 is real. It follows from that equation that 2 es | y at yr VE (4. —1__Y ) eX 173% 0+ Vy +z cos Vi eos i VPte =F sin (45 cos? 2.) as. +V7 i sin (45 cos) VPpae (13.) eed i eaci Fucay ateger os A Ng ce gia but 008 (75 08 Paro hi aint (14.) for an arc, whether ae or negative, ro the same cosine, and sin e= = 00S. | V 2 OE Va ew ba VPpte a for if an arc be respectively in the first positive or in the first negative semicircle, the sign of the sine of that arc will be positive or negative accordingly. At this step it is important to remark the necessity that ex- ists for the introduction of the expression , in order to z Vv 2° 2 —! ¥y secure the equality of en -1 W778 S04 Vy? +2 to a 4 i. 2 in all cases, for if that expression were omitted, Y & and therefore sin (cosy a) substituted for Vy? + 5 z = sin re orn Wirrs) we should not have f —1 sin ( cos FS: ( o+ V¥ aa) oFre + 32? unless z happened to be positive; for since the sum of the squares of the sine and cosine of any arc is equal to 1, and since the sign of the sine of an arc in the first semicircle is al- ways positive, the sine of cos Se Divas will be oy a poe A GigE NBGA i AR sak ia ey aaa [To be continued. } [ 342 ] LXVII. Experimental Researches into the Physiology of the Human Voice. By Joun Bisnopr, Esq., Sc. &e. (Continued from p. 277, and concluded. } file falsetto, or voce di testa, has always been considered a most embarrassing subject of research, and its peculiar quality has excited the attention both of the physiologist and of the musician. The change produced in the voice when pass- ing from the falsetto into the common tone, or the reverse, is in some persons very sensible to the ear, whilst in others it is al- most imperceptible. It is remarkable that some individuals have the faculty of producing, in the same pitch, three or four tones, possessing either the falsetto or the common character, a circumstance which indicates that the difference between them depends rather upon an altered state of the vocal tube than upon any change in the glottis. _ The falsetto has generally been ascribed to some particular adaptation of the upper ligaments of the larynx. Dodart * has attempted to prove that it is a supra-laryngeal function, and that the nose becomes the principal tube of sound instead of the cavity of the mouth. Bennati+ also considers these tones to be modified by the supra-laryngeal cavity, an opinion not justified by the experiments which he has detailed. According to this hypothesis, we must suppose the influence of the trachea to be entirely annulled; but on what acoustic principle this is to be effected he does not explain, nor indeed can any one else. ‘The changes observed by him in the pha- rynx were undoubtedly associated with corresponding changes in the whole length of the tube, and all the phenomena he has described may thus be readily explained. It was suggested to me by Mr. Wheatstone, that it was only necessary to suppose the vocal tube capable of subdividing its vibrating length to account for this peculiar character of tone. Analogous effects are observed in the clarionet, the flute, and other instruments; the change taking place at the twelfth of the fundamental note in the former instrument, and at the octave in the latter. Having had an opportunity of examining the phenomena in some individuals possessing remarkably fine voices, I placed my finger lightly on the larynx, and requested them to gradually elevate the voice from the primary to the falsetto tones, when, although the ear could scarcely distinguish * Mem. de? Acad., 1707. t+ Recherches sur le Mechan. de la Voix Hum. Mr. Bishop on the Physiology of the Human Voice. 343 the moment of transition, I found that the larynx suddenly fell, and then continued to re-ascend as the tones became more acute. On observing the motions of the larynx in a mezzo-soprano voice, I found a double falsetto, consisting of several tones of each register, with the power of yielding either the primary or the falsetto character. In this case the larynx fell twice, but ina much smaller degree. An instance of this kind of voice occurs in Miss Lanza. At the moment the la- rynx falls, during the continued ascent of the tones, the co- lumn of air and the tube become divided into portions separated by nodes, yielding harmonics of the fundamental notes, and the modulations of the voice are regulated, as before, by the divided length and relative tension of the tube. A much smaller quantity of air is sufficient to produce these tones; conse- quently, public singers who chiefly employ the falsetto, suffer much less fatigue than those who use the primary notes. In conducting these observations, care must be taken that the voice do not ascend or descend the scale too rapidly, other- wise the effect may escape detection. In further confirmation of these views it may be remarked, that when the glottis is in- jured and silenced by disease, the voice is entirely annihilated, which could not be the case if there were any means of pro- ducing sound by the superior ligaments of the larynx. There is, however, no doubt that the human voice derives a portion of its peculiar quality from the reverberations of sound in the cavities of the chest and head, modified by every change in these cavities as well as in the vocal tube. (The great effect produced by the nasal cavities on the voice is well known.) Much pains have been taken by physiologists to find an analogy between the organs of voice and artificial musical in- struments. Amongst those which have been selected for this purpose are the drum, the duck-whistle, the reed, and various other wind and stringed instruments. These attempts serve to illustrate the complicated structure and functions of the vo- ‘cal organs; but it appears to me more simple, and at the same time nearer the truth, to consider them in the following point of view : They consist of elastic membranes inclosed in a tube. The glottis is a most complex and beautifully constructed mem- branous vibrating apparatus, exquisitely adapted for producing all the tones of the voice. The vocal tube, or pipe, is adjusted on the most refined acoustic principles, to yield with the glottis isochronous vibrations. The perfect adaptation of these organs, in a manner inimi- table by mechanical art, to produce the most melodious sounds, 344 Mr. Bishop’s Experimental Researches into and to vary them so as to imitate the tones of birds, beasts, and musical instruments, with an almost infinite variety of other sounds, justly excites our admiration and astonishment. Not- withstanding the great labour bestowed by musicians on the temperament of keyed instruments, with a view to correct the dissonances occurring in the construction of the diatochromatic and enharmonic scales, so as to satisfy the ear, such instru- ments are far inferior to the vocal organs, which can produce all the tones necessary for the most exquisite and perfect har- mony. The association of the organ of hearing with that of the voice tends materially to its utility and perfection. Congeni- tal deafness deprives a person of the power of acquiring arti- culate language, except by a laborious process of tuition and to a limited extent. By very slight modifications of the tube, the simple unin- terrupted tones of the voice will produce the vowel sounds, which have accordingly been imitated by Kratzenstein, De Kempelen, Willis, and others, through the medium of artifi- cial mechanism. ‘The interrupted sounds, or voces limitata, require, on the other hand, the co-operation of the pharynx, tongue, teeth, cheeks, lips, and nostrils; the various actions of which, by checking the sounds, produce the gutturals, dentals, and labials of grammarians. According to the mode in which the interruption takes place, and to the varied adjustments of the organs employed in effecting them, these are distin- guished into mutes, explosives, nasals, liquids, and gutturals : but the manner in which these effects are produced, it is not my present purpose to investigate, and indeed they have been already minutely analysed by Haller, Scemmerring, Blumen- bach, Bell, Magendie, Bichat, and others. In the use of ar- ticulate language the variations of the voice are usually within a minor third, either above or below the pitch of the vocal tube, and the inflections of tone are generally in the minor key. When in the vibrating position, the glottis is capable of yielding sounds during inspiration, which are used by some persons for the purposes of ventriloquism. The expressions of pleasure and pain are produced by mere variations of tone, without the aid of articulation. In laughing, the voice is re- peatedly interrupted, in consequence of the glottis being al- ternately opened and closed in quick succession. In crying, the tones follow each other in enharmonic and discordant, but longer intervals. The views here taken of the functions of the vocal organs, and of which the following is a brief summary, are confirmed oe the Physiology of the Human Voice. 345 both by analogy and by experiment, which, I conceive, af- ford demonstrative proof of the truth of the theory now ad- vanced, and completely refute those to which reference has previously been made*. First. The vibrations of the glottis are the fundamental cause of all the tones of the human voice. Secondly. The vibrating length of the glottis depends con- jointly on the tension and resistance of the vocal ligaments, and on the pressure of the column of air in the trachea. Thirdly. The grave tones vary directly and the acute tones inversely as the vibrating length and tension of the vocal li- gaments. Fourthly. The vocal tube is adjusted to vibrate with the glottis, by the combined influence of its variations of length and of tension. Fifthly. The elevation of the larynx shortens the vocal tube, and its depression produces the contrary effect. The diameter and tension of the tube vary reciprocally with the length. Sixthly. The falsetto tones are produced by a nodal divi- sion of the column of air, together with the vocal tube, into separate vibrating lengths. Seventhly. The pitch of the vocal organs, when in a state of rest, is in general the octave of their fundamental note. In conclusion, it may be remarked that the physiology of the human voice cannot fail to be a subject of interest to every inquiring mind, and many whose names shed a lustre on sci- ence have devoted a considerable portion of their time to its investigation. ‘The advantages resulting from the study of the voice not only tend to enlarge the sphere of natural know- ledge, but also, in a medical point of view, serve as a basis for diagnostic, therapeutic, and pathological inquiry, and conse- quently contribute to the general benefit of mankind. Animals far inferior in their organization and intellect to man, are endowed with the power of uttering tones sufficient for the sphere of their existence. The roar of the lion, the lowing of the ox, the song of birds, and the hiss of serpents constitute a natural language which adequately expresses their wants and their passions, and is sufficient for the degree of intelligence belonging to the rank which they occupy in the scale of animal organization. * The hypotheses of Aristotle and Dodart respecting the size of the chink of the glottis must necessarily place the thyro-arytenoidean liga- ments out of the vibrating position: the same objection applies to that of Ferrein. The theory of tension requires the glottis to be always open, and vibrating in its whole length, to produce every tone of the vocal scale, a supposition which is opposed both by observation and by experiment, Third Series. Vol. 9. No. 55. Nov. 1836. 346 Mr. Bishop’s Experimental Researches into “Tis sweet to hear the honest watch-dog’s bark Bay deep-mouth’d welcome, as we draw near home ; *Tis sweet to know there is an eye will mark Our coming, and look brighter when we come. Tis sweet to be awakened by the lark, Or lull’d by falling waters—or the hum Of bees—the voice of girls—the song of birds— The lisp of children, and their earliest words.” The human voice may be denominated the music of the mind; language, a figurative mode of expressing our ideas and sentiments. ‘The effects flowing from this beneficent en- -dowment are overwhelming in contemplation and almost infi- nite in extent. It is principally instrumental to all the moral -and physical improvements of man, and enables him to pour forth his otherwise invisible, inaudible, unfathomable thoughts, to his fellow-man and to his God. Explanation of Plate 111. Fig 1, Is a representation of the larynx, having the left wing of the thyroid cartilage removed, to expose a portion of the internal structure. a. The right internal surface of the thyroid cartilage. 66. The arytenoid cartilages. cc. The thyro-arytenoid ligaments; the mucous mem- brane being removed. d. The chink of the glottis. ee. The posterior crico-arytenoid muscles. Jf: The left lateral crico-arytenoid. g- The cricoid cartilage. h. The trachea. z. The membranous and muscular portion of the tra- chea, which regulates its diameter. Fig. 2, Is a representation of the larynx, similar to fig. 1, showing the whole of the muscles of the left side at one view. The mucous membrane is dissected away, and the upper edge of the thyro-arytenoid muscle slightly depressed, to expose the ligaments of the glottis. a, b, c, e, f. The same as in fig. 1. d, The thyro-arytenoid, superior muscle. g- The cricoid cartilage. h. The thyro-arytenoid muscle. zk. The trachea. Fig. 3. This figure presents a section of the larynx, imme- diately above and parallel to the plane of the glottis. The view is vertical, with the mucous membrane removed to show the mechanism by which the voice is principally modulated. a. The rimula glottidis in a state of relaxation. 6 6, The thyro-arytenoid ligaments. the Physiology of the Human Voice. 347 ec. The thyro-arytenoid muscles. dd. The lateral crico-arytenoideal muscles. e. The edge of the thyroid cartilage. ff The arytenoid cartilages, with their perpendicular projections cut through at f g. A portion of the transverse arytenoid muscle. hh. The posterior crico-arytenoid muscles. Fig. 4, An internal anterior view of the larynx, produced by a section transverse to its antero-posterior diameter. a. The epiglottis. b b. The os hyoides. cc. The segments of the internal surface of the thyroid cartilage. dd. The thyro-arytenoid muscles. ee. A portion of the thyro-epiglottideal muscles. Sf: The pseudo-glottis. og, The sacculus laryngis. hh. The cricoid cartilage. ii. The chorde vocales, lying nearly parallel to the axis of the vocal tube. k. The internal aspect of the trachea. Fig. 5. The posterior segment corresponding to fig. 4. a. The pharynx. bb. The arytenoid cartilage invested by its mucous membrane. cc. The chorde vocales. dd. The thyro-arytenoid muscles. ee. The wings of the thyroid cartilage. Sf The cricoid cartilage. g. The trachea. Fig. 6. This figure represents a transverse section of the larynx: the thyro-arytenoid ligaments are turned perpendi- cular to the axis of the vocal tube; the glottis is seen in the true vibrating position. aa. A section of the thyro-arytenoid ligaments. bb. The pseudo-glottis. cc. Asection of the thyro-arytenoid muscle. Fig. 7, Is an external side view of the larynx, showing the action of the crico-thyroid muscles, by which the cricoid is rotated with the thyroid cartilage, and the tension of the local ligaments affected. a. The situation of the insertion of the vocal ligaments. 6. The upper posterior edge of the cricoid cartilage, to which the arytenoids are articulated. c. The left crico-thyroid muscle. d. The articulation of the thyroid to the crico-cartilage. e. The dotted line, showing the position of the cricoid 282 348 Mr. Williamson on the Limestones cartilage when rotated with the thyroid, whereby the antero-posterior diameter of the larynx is enlarged and the vocal ligaments stretched from ad to ae. Jj: The chink between the thyroid and cricoid cartilages. The dotted line represents the closing of this chink when the cricoid is rotated on the axis of motion of these cartilages at the-point d. Bernard Street, Brunswick Square, June 7, 1836. LXVIII. On the Limestones found in the Vicinity of Man- chester. By W. C. Witttamson, Curator of the Museum of the Manchester Natural History Society. [Continued from p. 249, and concluded.] Secr. VII.—Other Localities where Limestones are exposed. At two more localities limestones have been pointed out to me by Dr. Charles Phillips, who has contributed so much towards the elucidation of the geology of this district ; both of these were exposed by the cutting of the Liverpool and Man- chester Railway. One of these is at the base of the Sutton inclined plane on the Manchester side, and the other near Whiston, on the opposite side of the hill, forming two of the points which guided Mr. E. Hall in laying down the range of the magnesian limestone, with which he confounded them. That at Whiston is exposed for about seventy yards, and forms a seam six feet thick, but which never rises more than nine feet above the level of the railway and is covered for some extent by a series of solid sandstones. The top of the lime- stone consists of a greenish conglomerate, below which is pre- sented the reddish conglomeroid structure peculiar to the Ard- wick limestones, and the lower portion of the seam is composed of the solid gray limestone common at the above locality. From its so strongly exhibiting the peculiar mottled ap- pearance, I am of opinion that it will correspond with the uppermost or four-feet seam at Ardwick. This is in some measure confirmed by the occurrence of the same minute tur- binated shells (Planorbis?) found in the Ardwick series; but as no borings have been made on the spot, I cannot be certain as to what exists below. The limestone at Sutton I cannot identify with any exposed at Ardwick, although in its appearance and fracture it resem- bles the thin one of two feet below the main limestone on the bank of the Medlock. It is only about a foot thick, and rests upon a long range of the coal shales, which are very well ex- posed, exhibiting many partial faults and thin coal seams. As I before described, at Collyhurst we have the magnesian limestone laid bare for a small space; and about half a mile found in the Vicinity of Manchester. 349 further, on St. George’s Road, the coal measures appear at the pits of E. Buckley, Esq. According to the regular range of the strata, we ought to find the Ardwick limestones exposed between these two points, but they do not appear: on an ex-= amination of the locality, the reason is obvious; the red sand- stone ranges unconformably with the coal strata, overlying their outcropping edges, and thus completely covering up that portion in which the limestones ought to have been met with. The locality is a very difficult one to examine and decide upon, from the want of sections at the most important points; but as there is no doubt of the sandstone overlying the edges of the coal strata, and the dip of the latter being such as would carry their upper portions beneath where we find the red sandstone on the surface, the apparent deficiency is accounted for. Sect. VIII. Organic Remains. The fossil remains of this series of limestones, with one or two exceptions, are neither numerous nor exhibiting much variety, although they are of a peculiar character: these we will examine in their separate classes, and then from their evidences endeavour to draw some conclusion as to the nature of the limestones and the circumstances under which they were deposited. 1. Vegetable Remains. These are not so numerous as, from the connexion of the strata with the coal measures, might have been expected, al- though further investigation will doubtless bring new deposits to light. Biomaria _ ficoides is found abundantly in the seam of coal im- mediately below the black bass. The coal appears to have been entirely composed of this plant, as it is the only one I have hi- therto found in connexion with it. The character this extraor- dinary plant must have given to the primeeval world cannot fail to have been highly singular, as from the highest to the lowest coals of this group of strata its abundance generally forms a conspicuous feature, whilst its range appears to have been almost universal. In a seam of indurated blue clay, below the black bass, the leaves of Stigmaria are found in the greatest profusion. The same is observed in a reddish clay on the bed of the Medlock, much lower in the series. In the blue clay, immediately above the black bass, I found a small and beautiful species of Sphenophyllum, much like Sphen. erosum, but with broader leaflets, and fewer in each whorl. In the same clay occurred fragments of a species of Pecopteris and also of an Eguisetum, neither of which I was able to preserve. In working through a narrow passage of one of the mines, 350 Mr. Williamson on the Limestones used only as a drain to carry off the water from the pits, Mr. Mellor and myself were rewarded by the discovery of a thin seam of red shale, about sixty feet above the main or three yards limestone, filled with the most beautiful remains of plants, which fully confirmed the opinion Dr. Charles Phillips had been the first to form and advance. Amongst these were large specimens of Calamites decoratus, Brongn., and Cal. no- dosus; stems of Lepidodendron Sternbergiz, an elegant species of Neuropteris* with large leaflets, a small Cyclopteris, leaves of Stigmaria ficoides, fragments of a Pecopteris, Asterophyl- lites, and several other plants common to the coal series below, forming a character which, if any truth exists in the theory of identification, cannot for a moment be mistaken. 2. Mollusca. These, like the plants, are not of numerous species. In the three limestones worked at Ardwick, and also at Whiston, but most abundant in the Three Yards mine at the former lo- cality, are countless myriads of a small depressed turbinated shell, the merit of the first discovery of which is due to Pro- fessor Phillips, who is at present investigating its nature. It bears the strongest resemblance to a Planorbis, and is evi- dently of a nature very similar to the one found at Burdie- house, by Dr. Hibbert, and figured in his memoir (page 13.). In form it closely resembles the recent Planorbis Nautilus (Flemirg,) but is rather smaller. It occurs, as I said be- fore, in all the limestones worked, and Dr. Phillips found the same fossil in the limestone at Whiston, and also in a frag- ment of shale from the colliery of E. Fitzgerald, Esq., at Pen- dlebury, about four miles from Manchester. It was found in sinking down from the upper or “ two-feet coal” to Buckley’s “‘ three-quarters mine,” the highest coal of any importance in the Lancashire coal-field. The black bass is literally filled with fragments and perfect shells of a species of Unio of small size. It bears a considerable resemblance to Hibbert’s Unio nuciformis from the Burdie- house limestone, but is of a less globular form. This shell varies considerably in size, being sometimes one and a half inches in length, and at others not more than three quarters of an inch. The depressed and crushed state in which these fossils are found would indicate a shell of a thin and fragile nature, and such it has doubtless been: they are most frac- tured towards the lower portion of the bass, no perfect ones being there observable, but towards the top they are generally uninjured, further than has been the result of pressure. Of * This I find to be Neuropteris cordata, which Dr. Phillips has since met «vith in the coal measures at Oldham. found in the Vicinity of Manchester. 351 this shell, I found a single specimen in the blue clay which contained the Sphenophyllum; and in one of the thin seams of red clay, above the first limestone, they are also to be met with, though of a smaller size. Dr. C. Phillips found them at Pendlebury, in the fragment of shale containing the Pla- norbis. ‘This was the circumstance that first induced the above gentleman to differ from former observers in his opinion as to the relative position of the Ardwick limestone, separating it from the saliferous and connecting it with the carboniferous group of rocks, an opinion of the correctness of which there remains not the slightest doubt. My friend Mr. Joshua Alder, of Newcastle, informs me that he has met with an Unio, closely resembling our specimens, in the coal strata at the above place. This shell differs from the U. nuciformis of Burdiehouse in being broader and wider in proportion to its length, as well as in being a more fragile and delicate shell. Iam inclined to think it is an undescribed species; if so, I would propose the name of Unio Phillipsii as a slight return, not only for the private kindness J have met with from Dr. C. Phillips, but for the service that gentleman has done to geology by his indefatigable exertions in inyesti- gating the nature of these limestones, as well as being under his guidance in a district new to me when I first discovered this most characteristic shell. Towards the upper portion of the third limestone is found a thin seam of comminuted fragments of shells, amongst which may occasionally be found traces of more perfect specimens. These bear a close resemblance to, if they are not absolutely the same as, the fossil now under consideration. From the se- veral localities where these shells are found, and from their extreme abundance, combined with the rarity of other Mol- lusca of equal size, they must have formed an important feature of the fresh waters of that early era. In the blue clay, immediately above the black bass, are a series of remains, in attempting to decide upon the nature of which I find myself completely puzzled. They are very thin bodies of a brown colour, nearly square in their form, two of the corners being angular, and the opposite one rounded: I have some nearly a quarter of an inch across. At first I imagined that these were scales of fish, but now think they must be same bivalvular shell. Their surface is marked with strong concentric ridges, and passing from the hinge (?) to the opposite corners, are two diverging elevated lines. I can- not detect any traces of teeth, but have found several specimens in which the two valves (?) were connected at the hinge, and the four ridges commencing from one common point in the centre and diverging two each way: these I pointed out to 352 Mr. Williamson on the Limestones Professor Phillips, who will perhaps be able to lay before the public some more decided opinion as to their nature. 3. Entomostraca. Microscopic fossils are always with difficulty assigned to their proper situations in the scale of organized life. This difficulty was experienced by Dr. Hibbert amongst the Ento- mostraca of Burdiehouse, and as a necessary consequence, we experience the same amongst those of Ardwick. Throughout the whole extent of the black bass, but especially amongst the broken Unionide near the seam of coal, we find abundance of minute remains, generally about 4,thof an inch in length, which can only be assigned to the above-named group of Crustacea. I am uncertain whether there are one or two species: if two, the one will be a Cypris, approaching very closely to Cyp. Fuba in its beanlike form, but rather more elongated: the chief ob- jection is, our not being able to detect the hinge. ‘The other species, if different, is in reality subunivalve, with a lateral opening on one side: this is closely allied to the recent Daph- nia, and is probably of Hibbert’s genus Daphnoidea. It is of the same size and outward form as the one above described, of which it may only be the opposite side, showing the natural groove: when largely magnified, I cannot compare it to any- thing better than the berry of the coffee-tree after it is burned. To judge from the drawings Dr. Hibbert has given, I think our Daphnoidea presents the lateral opening much more di- stinctly than any he has observed, from which ours differ in being perfectly smooth instead of granulated. From these remains we have, without any other evidence whatever being wanted, a strong proof of the freshwater origin of this portion of the series. 4. Remains of Fish. We now come to the group of remains which first attracted my attention in the limestones of Ardwick. In June 1835 I first detected remains of fish in the black bass, and have since then at various periods made new additions to my collection. As we have in no one instance discovered a perfect specimen, the difficulty of identifying them with any known species must of necessity be great, especially as they are in such a crushed state that not even two scales can be found preserving their relative positions. In the fifth number of the Zoological Journal, published April 1825, is a drawing and description, by the late amiable and talented E. S. George, Esq., and J. D. C. Sowerby, Esq., of a remarkable bony plate, which the writers imagined to bea portion of the palatal bone of some fish, found near Leeds in the seam of coal commonly known in Yorkshire by the name Sound in the Vicinity of Manchester. 352 of the Beeston seam: this has since been examined by M. Agassiz, who pronounced it to be a portion of the large tuber- culated scale of some species of fish. In the main limestone at Ardwick was found a specimen so exactly resembling the one from Leeds, that the drawing would almost serve for a representation of either. The only difference I am able to perceive is, that the marginal portion, which in the Leeds specimen is smooth, in ours is slightly tu- berculated. It is also of an irony colour, whilst the other is described as being of a bright glossy black. The specimen was presented to the Society by Mr. Francis Mellor, the director of the Ardwick lime-works. In one very thin seam passing through the black bass, the position of which is generally marked by a line of pyrites, are found remains of a small species of fish, much crushed, the fragments being all detached. Of the scales I possess several forms: they are generally small, rhomboidal, and of a bright glossy black, often corru- gated on the surface. Others are arrow-shaped, about one third of an inch long, having a depressed sulcus passing along the centre especially at the broad extremity, and irregular striz towards the apex. A third form, very thin, irregular in size, and marked with dots and undulating lines, I at first mistook for pa- lates, but on comparing them with a specimen of a Palaeoniscus from the copper slate of Eisleben, I was enabled to determine to what portion of the fish each scale belonged: the thin un- dulated ones are portions of the reticulated covering of the head; the rhomboidal, some smooth and some corrugated, belong to the ody; and the larger arrow-shaped ones have formed a single line along the dorsal ridge, from near the dorsal fin to the insertion of the tail. I cannot venture to say that they are of the same identical species, but they certainly approach very near in their characters. In one instance I found part of a small jaw-bone of some species of fish, which may have some connexion with the scales above described: it is about 3rd of an inch in length, and is furnished with a regular row of obtuse, glossy black teeth, eleven or twelve in number, and about 7th of an inch in length. It is from the black bass. The same fruitful seam contains strong bony rays, similar to what we often find supporting the large dorsal fins of many species of fish. They are generally depressed, although we occasionally meet with them in their original rounded form. I have one specimen 2} inches in length, but which must have been considerably longer. The most singular fossil I have yet met with is a specimen Third Series. Vol. 9. No. 55. Nov. 1836. pid & 354 Mr. Williamson on the Limestones from the black bass, and evidently connected with the teeth of fish. Attached to a peculiar round body are two teeth (?) about half an inch long, with the two lateral cutting edges finely denticulated: they are separated about ;1,th ofan inch at their base, but diverge until their points are nearly half an inch asunder. I only know one portion of a fish to which this sin- gular fossil could belong, and that is, the apex of the upper jaw. In many species of foreign fish are two teeth in that situation which diverge as in our specimen, and this must have been of a similar nature. It may belong to the same species as the long rays*. In-the roof of the Four-feet mine, Professor Phillips has been so fortunate as to discover remains of Megalichthys Hibbertii, a fossil which is now apparently diffused through several of the limestones of the coal series: Mr. Mellor has in his possession a beautiful specimen of a lower jaw with a row of five teeth, with several other fragments. These are generally indistinct and ill’defined in their outlines. With the excep- tion of Mr. Mellor’s beautiful jaw, the finest specimens of this interesting animal have fallen into the possession of Professor Phillipst, who will doubtless, in his expected paper at the meeting of the British Association, give a detailed account of them, and their affinity with specimens from other districts which I have not had an opportunity of examining. The following catalogue comprehends such remains as we have now discovered in and above the third or main limestone: Plante.—Neuropteris cordata, Pecopteris, Sphenophyllum, Sphenopteris linearis ?, Cyclopteris, Lepidodendron Sternbergii, Stigmaria ficoides, Cala- mites decoratus, Calamites nodosus, Asterophyllites. Mollusca.—Planorbis, Unio, unknown Bivalve ?. Entomostraca.—Cypris, Daphnoidea ?. Ichthyolites.—Paleoniscus (scales and teeth). Teeth, opercular bone, and rays of an unknown species. Megalichthys Hibbertii (scales, lower jaw, teeth, &c.). Sect. IX. General Results and Inferences. From these detailed descriptions and simple facts, we may draw a few inferences as to the nature of the limestones and the circumstances under which they have been deposited. This group of limestones hus hitherto, as I before observed, * Since the above was written I have discovered a second specimen of this most interesting fossil, closely resembling the one described, with the exception of being rather smaller: it throws no new light upon its nature, except exhibiting a small rounded tooth or process, about 4th of an inch long, fixed between the other two, At the same time | found an opercular bone, probably connected with the same species. ‘+ Since then I have found a large scale of this animal in the black bass, of a rhomboidal form and closely resembling the scales of the thigh of the American alligator. found in the Vicinity of Manchester. 355 been confounded with the magnesian limestone, which latter stratum had never been distinctly identified in this neighbour- hood, until an examination of the fossils of Collyhurst led me to the conclusion, that the clays and thin limestones there exposed were the representatives of that series, so important in Yorkshire and Durham. On comparing the fossils of the magnesian series with those from Ardwick, we shall find that no one species found at the latter place agrees with any yet discovered in the magnesian limestone in England, the stron- gest evidence that they do not belong to the above series of rocks. The small fish bears a considerable resemblance to the Palzoniscus from the copper slate or zechstein, a stratum concerning the relative position of which I have some doubt. On comparing the fossils, however, with those from the car- boniferous system, we immediately observe their identity: we have Stigmaria jficoides, the almost universal characteristic of the coal measures of Lancashire and Yorkshire; several Filices, especially a Sphenophyllum, a genus, I believe, confined to the coal series; Calamites, and the still more important leaves and. stems of the Lepidodendron Sternbergit. However undecided we might be previously, the discovery of these remains cannot leave the slightest doubt as to their connexion with the car- boniferous group. The merit of the discovery of this important generalization belongs to Dr. Phillips, who, in May last, explained his views to the section of the Manchester Philosophical Society, and expressed his firm conviction that geologists had hitherto been in error in connecting these limestones with the magnesian series; and the deciding upon the relative position of so large amass of strata, in such close connexion with the Lancashire coals, cannot be viewed otherwise than as an important result. On a slight examination of the fossils, we observe another important fact: no marine remains whatever have yet been dis- covered. When we find freshwater remains mingled with those of marine origin, the probability is that the deposit was formed in some estuary or mouth of some large river; but here the remains are entirely of freshwater origin. All the most important fossils which guided Dr. Hibbert in arriving at his splendid results at Burdiehouse, we find here. The entire abs- ence of marine remains : the extreme abundance of microscopic freshwater Entomostraca, of Unionide; fish of the genus Pa- leoniscus; minute univalves, in all probability of the freshwater genus Planorbis; and lastly, the discovery of remains of Me- galichthys Hibbertii, all concur in assigning to the limestones a freshwater origin, It would be needless for me to enter here into any long salnigaes on the nature of freshwater 212 356 Dr. Mitchell on the Beds immediately above Jimestones, or the manner and circumstances under which they’ have been produced, as that has been done in so masterly a style by Dr. Hibbert, in his memoir on the Burdiehouse lime- stones: and the fact of the occurrence of freshwater lime- stones in the carboniferous group has become so firmly esta- blished, that what remains to be done is a careful investiga- tion of the districts where the coal measures are exposed, in order to trace how far they extend, and what varieties of re- mains of animal life they present. The ultimate result, I have no doubt, will be a vast mass of evidence respecting the cir- cumstances under which the coal measures generally have been deposited, and a considerable additional light will thus be thrown upon the origin and formation of the coal itself. Thus, as the small mountain rivulet, receiving new force and power from the most insignificant sources, gradually rolling on towards the wide ocean, becomes the broad and noble river, so each new fact, however trifling in itself, will give a slight but additional impetus to the stream of knowledge which is fast bearing us forward to the ocean of some grand theory of geology: the collection of facts thus slowly accumulated will one day be grasped by some comprehensive and master mind, —a new Newton will arise and place in our hands one universal outline of the laws that have guided and still guide nature in her unvarying progress. W. C. Wittiamson. Hall of Manchester Natural History Society, August 12th, 1836. LXIX. On the Beds immediately above the Chalk in the Counties near London. By James Mrrcuri1, LL.D., F.G.S.* (THERE is a description of flints found in beds immediately over the chalk, and below the sand, in all the places where these strata are seen to meet, in the counties of Surrey, Kent, Essex and Hertford, and may very probably also be found in other counties, also in similar situations. There are sixteen localities in which I have seen this flint on the south side of the Thames, and five on the north side. The pits on the south side are: Pit close to Croydon in Coomb Lane. Road to Tunbridge beyond Farnborough. Pit on the right of the road from Bromley to Chiselhurst. Pifin a vale on the south side of Elmstead near Chisel- hurst. : * Communicated by the Author. the Chalk in the Counties near London. 357 Loam-pit hill near Lewisham. Mouth of the Cavern on the side of Blackheath hill. Pit in Old Charlton on the south side of the Woolwich road. Great pit at New Charlton. Cliff opposite Woolwich dock-yard. Pit at Erith. Three pits near the bank of the river Cray near Crayford. Pit on the north side of the churchyard at Dartford. Trenches dug for forming a common sewer near Gravesend, on property belonging to Mr. Rosier. The entrance to the tunnel of the Thames and Medway canal at Higham. On the north side of the Thames the localities observed are, Purfleet, a pit on the west side and another on the east side of Belmont Castle near Grays, and a pit on the east side of Grays; also.a pit at George’s Farm near Hertford. A similar stratum is seen at Newhaven in Sussex, and the same flints have been seen in other counties, but not in their original site. At Purfleet the name given to these flints i is iron flints. The bed in which they are found is generally about eight or nine inches deep, seldom above a foot, and consists of a reddish clay with an abundance of oxide of iron. Scarcely any sand can be got from this clay by washing. It is stuck quite full of flints. Some of these flints are very small, not exceeding an inch in length; but the greater portion are three or four inches long, and some much longer. ‘They are round, and terminating in a point at each end, and on the whole in form not unlike a.cucumber. Some ancebt are of a triangular form. The exterior is covered with a rough black crust, which is found to be a combination of Silex and oxide ee iron. When broken by the hammer the oxide of iron is found to penetrate about a quarter of an inch all round, and there are frequently streaks of iron further in the interior. The body of the flint is black, but decidedly distinct from the dark blue flints found in chalk. The fracture is conchoidal, but these - flints, though not unmanageable, do not yield flakes in any direction so readily as the chalk flints. When burnt in the fire the exterior crust becomes reddish, and the rest of the flint is of a dirty white colour, not nearly so bright and beautiful as the porcelain substance made by burning chalk flints. It is exceedingly difficult, with ever so great caution, to get them burnt without cracking and flying in pieces. Such of these flints as have been exposed to the atmosphere have become partially decomposed immediately under the black crust. I have been informed by two gun-flint makers that such 358 Dr. Mitchell on the Beds immediately above flints afforded the best sort of gun-flints for gentlemen’s fowl- ing-pieces; but being less easily made than the gun-flints from the chalk flints, and the material being !ess abundant, they were more expensive. On account of the presence of so much iron they are totally useless in the porcelain manufac- ture ; but I have been informed that on one occasion as many as ten tons were obtained at the bottom of the great pit at Erith which were so pure as to be saleable for that purpose. Few specimens are large enough for building, and therefore their chief use is for road-material. An irregular broken line of flints of this description is to be seen at the sides of the deep cuttings at the entrance of the tunnel of the London and Birmingham railway beyond Watford. Great diluvial action has taken place, and the upper surface of the chalk is torn and ridged; and if, as we have no reason to disbelieve, there was a bed of sand here over the chalk, we must in consequence suppose that it has all been carried away. But the flints peculiar to such beds are seen above the solid chalk, and below the diluvial matter, scattered along on both sides of the cutting. I have seen such flints in considerable quantity in the fields on the east side of Margate, in the Isle of Thanet, and like- wise in Norfolk and Suffolk. In the pit on the south side of Elmstead near Chiselhurst, and in the pit on the south side of the Woolwich road, there are in the same beds with these flints innumerable small frag- ments of the same kind of flint, but not in the least rounded, and with sharp edges; which proves that in these localities there had been agitations, and that the flints had readily been broken into fragments. The most extensive section of this stratum which I have ever seen is at Newhaven in Sussex. It extends upwards of a mile along the top of the cliff, and the peculiar flints may be collected all along the foot of the cliff’ They are well known to the fishermen who collect chalk-flint boulders for the Staffordshire potteries, and are carefully avoided. One of these men said to me that he knew that one of them would be enough to spoil a hundred pounds’ worth of good material. I found a cast of an Echinus there, but not a particle of the shell remained upon it. There is another and very distinct variety of ftint, which may be seen in some of the pits in the same bed in which the preceding variety has been found. I may mention the pit at old Charlton near the Woolwich road, in the trenches dug by Mr. Rosier near Gravesend, and on the south side of Elmstead near Chiselhurst ; also at Purfleet. the Chalk in the Counties near London. 359 These flints are very large and of very irregular shape. They bear some resemblance to very large blocks of flint frequently seen towards the top of some chalk-pits. When broken with the hammer, however, they present instead of® the deep dark blue of the chalk flints a grayish surface, in many parts whitish, as if composed of silex differently granu- lated, and probably mixed with argillaceous or other matter. When burnt in the fire they appear still more decidedly dif- ferent in appearance. There are streaks of oxide of iron dif- fused near the surface, and in many instances throughout the whole mass. The whole flint has not been formed at once, but one part has aggregated after another, and the divisions are very perceptible to the eye. In the face of a fractured flint of this species is frequently seen one dark black piece surrounded with a mass of grayish flint, and sometimes more than one such dark piece. But sometimes also there is a grayish piece of flint surrounded by black flint: many divisions in curved and generally circular lines are perceptible. When burnt in the fire these flints separate into pieces, leaving almost smooth surfaces on both sides at the places of separation. These flints are totally useless for gun-flints or for the porcelain manufacture, but are excellent for build- ing. Such flints are well known at Northfleet, being found very abundantly in the loam immediately over the chalk-pits near to Gravesend. But the watery action there has been so con- siderable that there is merely a thin stratum of diluvial matter and vegetable mould over the chalk ; so that although I have known of them for several years past, it was not until a few months past I discovered them zn situ in the places already stated. They are not unfrequently seen in the fields in the . counties round London where the chalk comes up near to the surface. If a name be given to them it might be the gray iron flint. In this flint I have found at Northfleet abundance of Echini, the Echinocorys, Scutatus, Conulus, and Spatangus, generally much crushed, and the shells themselves totally gone, pro- bably corroded and destroyed by the oxide of iron. Mr. Parkinson, in a paper published in the first volume of the Geological Transactions, has remarked the difference of the casts found in the gravel from the casts found in the chalk, and contends that they are of different origin. I have no doubt they are the same species as those in the chalk, and that this bed which I have attempted to describe is the original habitat of the fossils to which he refers. 360 Mr. Saxton on his Magneto-electrical Machine ; The BEeps of sAnp immediately above these flints are of different kinds. _ At New Charlton it is a fine white sharp sand, and is used ‘in the foundries about London. The sand at Old Charlton is almost as good, but it is chiefly used for sanding floors. At Erith, Purfleet, and Grays it is only fit for ballast. But in the trenches dug by Mr. Rosier, and at Elmstead, it is quite different. On taking samples of this sand to London and washing it, and examining it when dry, I found it to be sand exactly the same as that which is well known near London as brickmakers’ sand, which is exceeding soft when felt between the fingers, and is used for sprinkling the brickmakers’ moulds to prevent the adhesion of the clay. It is obtained for that purpose from above the mud opposite to Woolwich, and off Crayford Point, and is, no doubt, washed down by the rain and brought into the Thames by the rivers Cray and Darent from the districts through which they run. In respect of the chalk immediately below these beds of flint, in most of the localities examined the surface is perfectly level, even, and unbroken; and it is not furrowed and indented as some observers have represented the upper surface of chalk always to be. That opinion must have been formed from the circumstance of the chalk, in almost all places where it is near the surface of the ground, having suffered much diluvial action ; and from chalk-pits generally being opened, from a motive of saving ex- pense, on the sides of hills, where there is little top surface to be carried off. In the pit at Elmstead it is, however, different from the other localities. There the chalk is cut into ridges, the hollows of which are filled with these flints and clays co- Joured with iron: which is a proof that in one instance at least the chalk may have suffered diluvial action before the formation of these flints and of the beds of sand over them; but being only one locality out of twenty-one, it shows that the general rule is otherwise. ' LXX. Mr. J. Saxron on his Magneto-electrical Machine ; with Remarks on Mr. E. M. Clarke’s Paper zn the preceding Number. To the Editors of the Philosophical Magazine and Journal. GENTLEMEN, I REGRET that I am called upon to notice a very disin- genuous article in the Number of the Philosophical Maga- zine for October. A reader unacquainted with the progress with Remarks on Mr. E. M. Clarke. 361 which magneto-electricity has made since this new path of science was opened by the beautiful and unexpected disco- veries of Faraday, might be misled, from the paper I have alluded to, to believe that the electro-magnetic machine there represented was the invention of the writer, and that the ex- periments there mentioned were for the first time made by its means. No conclusion, however, would be more erroneous. The machine which Mr. Clarke calls Ais invention, differs from mine only in a slight variation in the situation of its parts, and is in no respect superior to it. The experiments which he states in such a manner as to insinuate that they are capable of being made only by his machine, have every one been long since performed with my instrument, and Mr. Clarke has had every opportunity of knowing the truth of this statement. Though my machine is tolerably well known to the public from its constant exhibition at the Adelaide-street Gallery since August 1833, and my claims as its inventor have been acknowledged by Professors Faraday, Daniell, and Wheat- stone, in papers of theirs published in the Philosophical Transactions, yet as no description of it has yet been published, I will thank you to insert the following in the ensuing Number of the Philosophical Magazine. I think the figures and their explanation will be sufficiently intelligible to enable any work- man to construct a similar one. Fig. 1. is a side view of the magneto-electrical machine; the magnet is placed in a horizontal position, and consists of twelve plates of the horse-shoe shape firmly fastened together. A vertical wheel communicates motion to a spindle, which carries round with it a cross of soft iron, on the extremities of which are fixed four soft iron cylinders. Fig. 2 represents the spindle and cross before the wire is coiled round the cy- linders: when the wheel is turned, the bases of each of the cylinders pass in succession the two poles of the magnet as closely as possible without actual contact. Fig. 3 represents the side of the armature next to the poles of the magnet; A and B are the soft iron cylinders on which the long wire for giving the shock is coiled; and C D are the cylinders round which the short wires for giving the spark are coiled: the circular brass plates 1, 2, 3, 4 are for the purpose of keeping the wire on the cylinders. The wires are of copper covered with silk; that for producing the shock is a double wire 400 yards in length, and each 75th of an inch in diameter; and that for obtaining the spark consists of 20 lengths, each 75 feet long and ;',th of an inch in thickness, united together at their twoextremities. Fig. 4 is a front view of the armature, show- ing the soft iron cross to which the cylinders carrying the Third Series. Vol. 9. No. 55. Nov. 1836. 2U 362 Mr. Saxton on his Magneto-electrical Machine; with Remarks on Mr. E. M. Clarke. 363 coils are fixed. The front end of the spindle is, for the pur- ose of insulation, made of ivory or hard wood, and the lancet- shaped blades F are mounted on a copper wire, which passes through the centre of the spindle, and to which one end of each coil of wire is soldered. E is the copper disc which always-re- mains in contact with the mercury in the cup below, and is by a simple contrivance brought into contact with either of the other ends of the two coils. This contrivance is shown in fig. 5, which is an enlarged and side view of the front end of the spindle: at G, in the socket of the copper wheel, is a notch, in which termi- nate one end of each of the wires A Band C D;; one side of the notch is represented in contact with A B, or the long wire for giving the shock, but by twisting the socket partly round the other side of the notch it will be brought in contact with C D, or the short wires for showing the brilliant spark, and pro- ducing the strongest heating effect. The points F in fig. 4, are in the proper position to take the spark from the coils C D, provided the socket of the disc is in contact with C D. To obtain the spark from the coil A B, which is however far less bright than the former, the notch must be brought into contact with A B, and the points twisted round one quarter of a revolution, or to that position that they will leave the surface of the mercury at the instant when the coils from which the spark is to be taken arrive at their greatest distance from the poles of the magnet. For obtaining the shock, igniting wires, decomposing water, &c., the points should be removed, and the two ends of the wire forming the circuit should be connected, one with the mercury in the cup, and the other with the termination of the wire which passes through the insulating end of the spindle. The action of the machine will be more readily understood by confining the attention to a single circuit; for this purpose we must suppose two of the cylinders (those opposite each other) with their coils of wire to be removed. Each of the soft iron cylinders becomes, from the known laws of induc- tion, a temporary magnet when it is opposite one of the poles of the permanent magnet: as each cylinder passes succes- sively both poles of the magnet, its poles are changed twice during each revolution, and the cylinders cease to be mag- netic when they are at equal distances between the two poles. Electric currents are induced in the coils round each cylinder, and on account of the alternate change of the poles, these currents are alternately in opposite directions. The part of the coil round one cylinder being, as above described, connected with the copper disc, and that round the other cylinder con- 2U2 364 Mr. Saxton on his Magneto-electrical Machine ; nected with the dipping points, so that the current in both parts of the coil is continuous in the same direction, it is obvious that by the rotation of the spindle the circuit is alternately broken and renewed, and a spark occurs every time either of the cop- per points leaves the surface of the mercury, into which the copper disc also dips, thus completing the metallic communi- cation twice during the revolution of the spindle. In the ar- rangement here described the successive transient currents are in opposite directions; to obtain a series of currents in the same direction, the double must be replaced by a single point, but in this case one half of the effect is lost. The first electro-magnetic machine, that is, an instrument by which a continuous and rapid succession of sparks could be obtamed from a magnet, was invented by M. Hypolite Pixii of Paris, and was first made public at the meeting of the Académie des Sciences on September 3, 1832. _ A description of this invention will be found in the Annales de Chimie for July 1832 (that journal is always published several months after its date), and a representation of it in Becquerel’s Trazté del Electricité, vol. iii. It differs from mine principally in two respects: first, in M. Pixii’s instrument the magnet itself revolves and not the armature; and secondly, the interrup- tions, instead of being produced by the revolution of points, were made by bringing one of the ends of the wire over a cup of mercury, and depending on the jerks given to the instru- ment by its rotation for making and breaking the contact with the mercury. With this machine, furnished with a coil about 3000 feet in length, sparks and strong shocks were obtained, a gold-leaf electrometer was made to diverge, a Leyden jar was weakly charged, and water was decomposed. My first complete magneto-electrical machine was exhibited at the meeting of the British Association at Cambridge in June 1833, and that now in the Gallery of Practical Science in Ade- laide-street was placed there in August of the same year. The effects first shown by my machine were the following: 1st, the ignition and fusion of platina wire; 2ndly, the excitation of an electro-magnet of soft iron (these were first shown August 25th, 1833); and 3rdly, those of the double arma- ture, producing at pleasure, either the most brilliant sparks and strongest heating power, or the most violent shocks and effective chemical decompositions; this was added to the in- strument in December 1835. I was led to furnish my magnet with the double arma- ture from the following circumstances. In November 1833, Count di Predevalli brought from Paris one of Mr. Pixii’s with Remarks on Mr. E. M. Clarke. $65 machines, and it was sent to the Adelaide-street Gallery in order that its effects might be compared with those of mine *. Mine was found to excel in the brilliancy of the spark, while M. Pixii’s machine was more effective in giving the shock and affecting the electrometer. M. Pixii’s machine had a larger keeper and a much greater extent of copper wire. Shortly after, Mr. Newman of Regent-street made a smaller instrument on my construction, which gave the shock more powerfully than my large one did: this also had a greater Jength of coil, but the effect was at that time partly attributed to the better insulation of the wire. I then convinced myself by some experiments that the increased shock solely depended on the length of the wire. The cause of the difference of effect in the two cases admitted no longer of dispute after the publication of the experiments of Dr. Henry of Philadelphia, Mr. Jennings, and Dr. Faraday; as their investigations fully proved that the spark is best obtained from a magneto- electric coil when short, and the shock when it is long. Mr. Clarke has no more claim to the application of the double armature to the magnet than he has to the discovery of the facts which suggested that application. In conclusion: I think it will be evident from the preceding statement, that the magneto-electrical machine which Mr. Clarke has brought forward, ‘after much anxious thought, labour, and expense,” is a piracy of mine; the piracy consisting not in manufacturing the instrument, —for every one isat full liberty to do so, but in calling it an invention of his own and sup- pressing all mention of my name_as connected with it. Ido not presume that Mr. Clarke is so ignorant as not to know the meaning of the word “invention,” but he has strangely misapplied it by calling several other well-known pieces of apparatus his inventions. Thus he has appropriated to him- self Ampére’s Bascule Electrique, and calls it the Electrepeter. Among other uses of this simple contrivance of the French philosopher, it was employed in Pixii’s magnet for the pur- pose of changing the direction of the current in the wire. 24, Sussex-street, London University. JosEPH SAXTON. * See the Literary Gazette, No. 878. [ 366 ] LXXI. Reply to Dr. Boase’s * Remarks on Mr. Hopkins’s ‘ Researches in Physical Geology’ ,” in the Number for July. By W. Hopkins, Esq., M.A., F.G.S., of St. Peter’s College, Cambridge. [Continued from p, 175, and concluded. ] HE two theories of the formation of veins of which I have spoken, equally depend on some process of infiltra- tion or segregation into previously existing fissures, and differ only in the manner in which those fissures are supposed to have been formed, in the one case by dislocation, in the other by the mass becoming jointed. There is no reason why both ° should not be true as applied not merely to veins of different districts, but also to different veins of the same district, and both will enable us to account for nearly all the phanomena referrible to mechanical causes which veins present to us. Let us now proceed to analyse the rival theory of the con- temporaneous formation of veins, of which Dr. Boase has been one of the ablest advocates. In the first place, then, What are the physical causes which this theory assigns for the observed phenomena? We cannot of course do better than answer this question by a quotation from Dr. Boase’s * Primary Geology*.” ‘Is it not within the bounds of probability that the chemical union of the elements of the fused mass (of the earth’s crust) whence resulted such a vast body of definite minerals, should be ac- companied by the evolution of numerous currents of electri- city, or of analogous fluids ? for we know that the oscillations of the particles of matter, whether produced mechanically or during chemical combinations, will elicit streams both of common and galvanic electricity. If, then, it be acceded that the primary rocks may have been traversed by such cur- rents during their formation, we have an explanation of the regular disposition of the granitic rocks, of veins, and other crystalline substances; and indeed not only of the subordinate arts but of the entire mass. «© This idea will remind the reader of Mr. R. W. Fox’s ex- periments, from which he has concluded that the Cornish me- talliferous veins were formed by electro-magnetism. By such imaginary currents, crossing each other in different directions, we also fancy that the phenomena of intersecting veins might be accounted for, the more powerful ones having uninter- ruptedly continued their course, whilst the weaker ones ex- * p. 385, Mr. Hopkins’s Reply to Dr. Boase’s Remarks. 367 perienced various degrees of diversion, being either partially or altogether involved in the impetus of their stronger oppo- nents.” Now it appears to me that all we can conclude from the above reasoning (and I am not aware that it has been put by any one in a better form) is this,—that ct 7s not impossible that veins may have been the effect of certain electric currents which, 7 is possible, may have existed. The theory rests, not on our knowledge, but entirely on our ignorance. We know not that these electric currents could be produced as above supposed, and we know not whether if they did exist they could produce the effects assigned to them. Let any one consider whether by any reasoning like the above he could give any rational account of such phenomena as the follow- ing: S. The approximate rectilinearity and parallelism of veins. 2. The relations which their directions usually bear in stra- tified masses to the dip and strike of the beds. 3. Their division into two principal systems, approximately perpendicular to each other. 4. The irregularity of the cross courses in width, as com- pared with the bearing veins. 5. The throw of a vein, or the difference of level of the same stratified bed in the opposite walls of the vein. 6. The general relation between the throw and the hade, or inclination of the vein to the vertical. 7. The numerous appearances of heaves and shifts in veins. These are some of the most obvious and general characters which mineral veins present to us; and yet I am not aware that the advocates of contemporaneous formation have made even an attempt (for as such we cannot regard the second paragraph of the above quotation) to account for one of these phenomena as a necessary or probable consequence of any definite physical cause connected with their theory, while all of them are, I conceive, perfectly accounted for on the hypo- thesis of an elevatory force, considered either as the original cause of fissures, or as modifying them when previously pro- duced by joints. In the present imperfect state of our know- ledge of geological causation, I would not positively reject any hypothesis carrying with it the most remote plausibility, provided it could be received without giving up others of stronger claims to our notice; and therefore I would not ab- solutely reject this hypothesis of contemporaneous formation as possibly applicable to certain veins, though I must still regard the process as an inconceivable one; but that we should adopt it with reference at least to the veins of our —" 368 Mr. Hopkins’s Reply to Dr. Boase’s Remarks. limestone districts, while it offers no rational explanation of a single pheenomenon they present to us, can scarcely be ex- pected, I conceive, even by its warmest advocates. I wish Dr. Boase had stated more distinctly the extent to which he conceived it applicable. Perhaps he will leave me quiet possession of the limestone districts and entrench himself within the Cornish veins, not allowing that the phenomena above mentioned are to be distinctly recognised in them. if however, we consult for a moment the map published by Mr. Thomas of the Camborne and Chacewater district, and that by Mr. Carne of the district of St. Just, we recognise im- mediately a system of veins and of cross-courses such as has been mentioned above. The irregular width also of the cross- ~ courses is universally recognised; and though I am not dis- posed to place implicit reliance on all that has been advanced respecting the heaves and shifts of Cornish veins, I should regard any one as a bold theorist who, for the sake of his theory, would set aside some of the facts of this kind which have been adduced. Whether the other phzenomena above stated under the heads (2.), (5.), and (6.) exist in many Cor- nish veins it is impossible to say, because evidence of them can only be obtained where veins occur in masses so stratified as to enable us to identify some particular stratum on opposite sides of the vein. But leaving these out of the question, does the theory of contemporaneous formation offer the smallest explanation of the other phenomena? It appears to me difficult to conceive a theory in a more perfectly unsatisfactory state than the one of which I am speaking ; and, indeed, I scarcely understand what claim that which affords no intelligible explanation of anything can have to the title of theory. It seems mere hypothesis, with- out any direct support from physical facts or physical reason- ing,—a negative of other theories rather than a theory itself; and the only foundation on which it appears to me to rest is the assumed insufficiency of more definite theories to account for some of the appearances presented by certain veins. Whether the two theories I have discussed will hereafier be deemed sufficient by geologists when careful observation shall have been made with direct reference to them, I pretend not to say, but I am quite certain that the theory of contemporaneous formation must rest on foundations very different from those on which it now stands before it can be admitted as affording any explanation of the formation of veins in general. One of Dr. Boase’s objections is founded on the want of sufficient coincidence between the Cornish veins and joints. At the same time it will be observed that he fully allows as a on * Researches on Physical Geology.” 369 fact, established by his own observation, the general coinci- dence of their directions; and this general coincidence, which seems equally to have struck Dr. Boase and myself, is pro- bably all that the theory of the formation of veins in joints would require. If we could descend into any master joint, and follow its course, we should no doubt find it frequently intersected by other joints, some of them belonging to other cross-systems, and others more partial and irregular. The continuity, however, of a cross-joint through the matter of the vein itself I should think a rare occurrence in our limestone districts, and I confess that I should be much surprised to find such to be anything like a general rule in the Cornish lodes. That such cases might occur, and not very unfre- quently, appears very possible, because it is probable, I think, that the process of the formation of joints was one of long duration, and might be continued after the segregation of many of the Cornish lodes into the earlier joints; and more particularly, perhaps, might this be expected in those cases in which the causes producing joints have acted with the greatest intensity, which appears to have been in the older rocks. It must be understood too that I here speak of the absolute continuity of a particular jozn¢, not of the general directions of cleavage of the mass. It would appear by no means improbable that the matter deposited in an open fissure should become subject to the same kind of action which might have previously produced a laminated structure in the sur- rounding mass. This presents, I conceive, no difficulty, be- cause it does not necessarily lead to the inference that this la- minated structure in the vein must have been superinduced contemporaneously with that in the containing mass, an in- ference which might be drawn from the continuity of distinct joints through the lode itself. With respect to what Dr. Boase appears to consider a 7e- ductio ad absurdum, it is manifestly unnecessary to say any- thing in direct reply, except what I have before stated, that it is totally inadmissible to assume the earth’s crust to have become jointed before the action of the dislocating force upon it. In what I have now advanced respecting these theories of the formation of veins, and of their relative claims to our ac- ceptance, I would beg to be understood as speaking with re- ference to existing evidence. With respect to the limestone districts I can feel little doubt of the result of more extended investigation. How far the two methods of formation will be found ultimately satisfactory as applied to the whole of the Cornish~veins, I pretend not to say with equal certainty. It Third Series. Vol. 9. No. 55. Nov. 1836. 2X 370 Addendum to Prof. Young’s Paper. is not that I feel the geology of Cornwall, as your corre- spondent has stated, a stumbling-block,—because, even if I were ultimately to adopt the theory of contemporaneous for- mation with respect to many of the Cornish veins, it would not change my opinion respecting the origin of those of our limestone districts, —but it is that the evidence obtained from the Cornish veins is essentially defective in a most important point, viz. as to the relative elevations of the beds on opposite sides of the vein, which can only be determined in distinctly stratified masses. It is this serious defect which, in a great measure, renders it so much more difficult to arrive at any positive conclusion respecting them than in other districts, and which ought to satisfy us that it is not in Cornwall that we must expect to find the tests of the truth of a theory which would attribute the pbznomena of veins to the dislocations of the mass in which they exist. I trust, however, that im- portant evidence may shortly be expected to be placed before us. From the ability and extensive knowledge of Mr. De la Beche we may hope to see new light thrown on Cornish geo- logy; the researches of Mr. Henwood in the mines of that di- strict are likely to abound with important facts; and we may perhaps be allowed to hope that Dr. Boase, who has the merit of being among the first to declare the importance of attending to the regular structure of rocks, will repeat his observations with more immediate reference to theories in which, however our present views may seem to differ, I feel happy to have interested him. Whatever may be the difference of our opinions, however, in speculative geology, I would express the hope which he has himself well expressed at the conclusion of his “ Primary Geology ”—“ that as fellow-labourers in one common cause we shall be actuated by a mutual esteem, and only strive, in friendly competition, who can render the best iuterpretation of the great and glorious mysteries of Nature.” I am, Gentlemen, yours, &c. Cambridge, July 20, 1836. W. Hopkins. LXXII. Addendum to Article LXV. in the present Number, by Professor YOUNG. "PE inverse problem, or that which determines the orbit from knowing the law of attractive force, may be solved just as readily as the direct problem by regarding re h ='N Pp’ Reviews, §c.—** The Botanist.” 371 or, which is the same thing, re R = Pp “ps? eeoenreres (3.) as the general equation of the conic sections. : . é 1 ees For since the force in the radius vector varies as po its P r - 4 : 1 component in the direction of the normal must vary as = But the normal force is and consequently 73 R= Oays vee (4) which equation, as it agrees with (3.), represents a conic sec- tion, whose parameter, 2 C’, is determinable from the initial circumstances of the motion. LXXIII. Reviews, and Notices respecting New Books. The Botanist ; containing accurately Coloured Figures of tender and hardy Ornamental Plants, with Descriptions. Conducted by B. Maund, F.LS., assisted by Professor Henslow. 4to. To be con- tinued Monthly. No. I. ib the progress of science there occur periods when the establish- ment of works devoted to any of its branches, upon new plans, be- comes absolutely necessary, in order to promote its advancement, by being conformable to the improvements already achieved. Former works cannot so easily be moulded to the changing conditions. of modern science as new ones can be accommodated to its state at the time of commencing their career. Hence, in the science to which the work reters, of which we have above transcribed the title, every succeeding work undertaken by competent persons has been an improvement upon its precursors. Most of those in existence up to this time have been suited or addressed to those only who were already conversant with its language and classification. But an attempt is here made to render an illustrated work suitable to those who have mastered its elements, and conducive to the acquisi- tion of these by beginners. The terms used in the descriptions of plants are in general unintelligible to the uninitiated, and therefore little more is learnt by reading the description than by looking at the plate. But in the work just started an explanation of every botani- cal term is given, by means of a glossary, from the pen of Professor Henslow, a portion of which, till it be completed, will accompany each number, and to which reference can be made in every case of AZ 372 Reviews, and Notices respecting New. Books. doubt. This is an advantage which belongs to no previous work, and must greatly enhance the usefulness of The Botanist. The plates, both in the matter of engraving and colouring, speak for themselves : they are ‘‘ beautiful exceedingly!’ The selection and treatment of the subjects figured reflect credit upon the conductor and his assis- tants, and if they avail themselves in the future numbers as judiciously of the varied resources at their command, the result will be the p ro duction of a volume, or, as we hope, many volumes, calculated to delight and instruct all who may open them, of whatever age or Sex. ale M. Mirset’s Report on a Memozr of M. Gaudichaud, relative to the Development and Growth of the Stems, Leaves, and other Organs of Plants, read in the Academy of Sciences at the sitting of the 21st December 1835.* When we have collected a great number of facts, when we have viewed them on every side, and have compared them with one another, observing with care their resemblances and differences, we feel ourselves stimulated by the desire to seek out the laws of their existence, to generalize those which are susceptible of it, and to form them into atheory. Without doubt prudence would often lead us to keep to the simple exposition of facts, but we cannot deny that it is very useful for science, that those who have disco- vered them should apply themselves to show us their connexion and dependence. Exact observations are never slow in obtaining the assent of all; theories, on the contrary, are subject to be for a long time contested. In this conflict of different opinions, the opposing parties bring forward all the known facts, put them to the test of a more rigorous examination, and discover others which had escaped preceding researches. Now, numerous and well-observed facts are what essentially constitute the unchangeable foundations of science. Thus, whatever be the issue of the struggle, there is a victory in favour of the human mind, and both the victors and the van- quished have often equal claims to public esteem. These reflections are suggested to us by the perusal of the work which M.Gaudichaud hasaddressed tothe Academy ,—a work which, on the one part, is composed of a multitude of new facts, of acute observations, and inductions as just as they are evident ; and, on the other, presents a general theory which rests upon that of Du Petit- Thouars, and considerably enlarges its basis. The material facts are certain, the theory which generalizes and professes to explain them, is still in doubt. De la Hire conceived it without supporting it by proofs: Du Petit-Thouars, by bringing together all the observa- tions that seemed to him calculated to support it, gave it a scientific existence; Agardh applied himself to reconcile it with the re- * From the Annales des Sciences Naturelles, tome vy. p. 24.—The prize for experimental physiology founded by M. Montyon for the year 1835 was divided between this memoir and that of M. Poiseuille upon the causes of the motion of the blood in the capillary vessels. Gaudichaud’s “ Vegetable Physiology.” 373 ceived opinions; and, quite recently, Lindley, an excellent observer and a man of sound solid judgement, has strengthened it with all the weight of his approbation. But we must allow that it reckons as yet at least as many adversaries as partisans. M. Gaudichaud arms himself to defend it with the arguments which his own dis- coveries supply. It is by the help of time only, and after a very serious examination, that we shall be entitled to pronounce on the validity of consequences deduced from facts too recently known for us to be able as yet to measure their just bearing. We shall there- fore confine ourselves to stating briefly the theory unfolded by the author, without venturing to approve or condemn it; but we shall not hesitate to give our opinion as to the accuracy of the numerous facts which he has brought together. The task which M. Gaudichaud has undertaken is no light one. He reviews in the following order the whole history of vegetable life : 1. Organography, or development and growth of the stems, &c. ; 2. Physiology, or phenomena of the life of plants ; 3. Organogeny, or anatomical study of the development of vegetable tissues. Organography, which forms the subject of the first part, subdi- vides itself into three chapters: 1. the dicotyledonee, 2. the mo- nocotyledonee, 3. the acotyledoneex. The author delivers at the present time, for the judgement of the Academy, the two first chapters of this great undertaking, the pre- cious materials for which are deposited in the botanical galleries of the Jardin du Roi, where they are become an object of study and admiration for connoisseurs. He sets forth the general principles by which he means to ex- plain not only the mode of development and the organization of stems, but also the mode of development and the organization of the processiles or appendicular parts, that is to say, of scales, leaves, stipule, bractez, calyxes, corollas, stamens, pistils, &c. which all take their birth in the bud. ‘These parts are only, according to his idea, modifications of a single primitive organ of which the monocotyledonous embryo is the type. In fact, in the same way that we see in the monocotyledonous embryo, when it has taken all its normal expansion, a radicular mamilla which constitutes its descending system, and a cauliculus, a cotyledon, and its support, which form together its ascending sy- stem, in the same manner also we see in the more advanced plant the root which represents the radicle, that is to say, the descendin system, and the merithallus with the leaf and its petiole, which represent the cauliculus, the cotyledon, together with its support, that is to say, the ascending system. This ascending system, modified in the other appendicular parts, is not, however, so modified as that there is found in it no trace of its distinctive features. The simple type which represents the monocotyledonous embryo becomes double, triple, quadruple, quintuple, &c., in the dicotyle- 374 Reviews, and Notices respecting New Books. donous or polycotyledonous embryo, and the same also is the case with the vascular provision which it contains. We cannot be silent on the merit of this sketch ; it is of an accuracy which is rigorously demonstrated by the anatomy of the young plant. The vascular provision is composed of two sets of vessels: the one is carried from the neck of the root to the bud; the other from the bud to the extremity of the root. The first raises as far as the bud the raw sap which is there elaborated; the second con- ducts as far as the root a part of the elaborated sap. This, in the dicotyledonez, being carried along between the bark and the wood, forms the new woody layers by its union with the utricles origi- nating from the stem, and contributes in this manner to the growth in diameter ; whilst the other, by extending itself forwards at the centre, and terminating at the bud which transforms into orga- nized matter a part of the sap come from the root, carries on the longitudinal growth. It thence follows that the bud receives from below nothing solid, nothing organized, that it creates altogether the vessels which enter into its composition, and that it is these same vessels, developed below, which are represented in the woody layers of the stem and of the root, of which they constitute the most important portion. And as to the utricles of the layers, whether they are carried on from beneath upwards, or from the centre to the circumference, they become organized on the spot between the bark and the wood, and have nothing in common with the bud. This series of phenomena, which takes place in the natural state of individuals, exists equally in those which are grafted. All the wood of the stem and of the root placed below the graft is coms posed of vessels emanating from the buds of the graft and of utri- cles engendered by the subject. ‘This proposition is the corner- stone of the theory; for if it were invalidated by observation, the theory would fall to pieces. The double vascular apparatus and the phenomena which result from its presence, Delong not to the dicotyledonee alone; they are also found in the monocotyledonez ; but they there undergo the modifications required by the particular arrangement of the threads of which the wood is composed. Such is in substance the doctrine which M. Gaudichaud pro- fesses. If we consider attentively, it is, as we. have already re- marked, only that of Du Petit-Thouars and of Lindley; but M. Gaudichaud has impressed upon it a character of generality which it had not. To come to this result, he has brought together a multitude of facts which, in whatever way they are interpreted, will conduce powerfully to the progress of science. His opponents it must be expected, will not fail to say that these facts, curious and unexpected as they may be, might be explained quite as well by their doctrine as by his. But notwithstanding this assertion, which should not be received on the strength of a simple dictum, as coming from persons who for a long time have formed another idea of the phenomenon of the growth of plants, all will agree, that by his Gaudichaud’s * Vegetable Physiology.” 375 new work, M. Gaudichaud has raised himself as high as our most skilful phytologists. It is worthy of remark that, during the fatigues of two long voyages, in spite of the wretched state of his health, this indefatigable naturalist never ceased to apply himself to re- searches of extreme delicacy, and that he has carried them as far as he would have done in the quiet of his closet. Here we can only name the least part of his most interesting observations. He has examined, drawn and described a multitude of seeds and embryos belonging to families still little known, such as the Nym- pheacee, the Piperacee, the Gnetacee, the Cycadea@. This last family supplied him, during his first voyage sixteen or seventeen years ago, with a succession of ovological facts of which some are still new, notwithstanding the recent investigations of MM. Corda and Robert Brown. He caused to germinate in their native climate, seeds of Piper, Peperomia, Loranthus, Avicennia, Bruguiera, Rhi- zophora, &c.; and he now gives us positive notions respecting the first developments of these plants, which will take the place of vague or erroneous opinions in science. At the same time that he was bringing together numerous herbarium specimens, he studied the interior of stems, and found in the structure and arrangement of the ligneous body, strange anomalies which would little have been suspected there. It was particularly these observations which sug- gested to him the project of bringing together all the facts of de- velopment and growth under general laws, a project the execution of which he has constantly followed up since his return to France. In order that every one may be able to verify the facts, he has chosen many examples amongst our commonest plants, and these have often furnished him with new views: we shall point out among others the radish, the turnip, the carrot, the beet, the horse chestnut. From the better known organization of these different vegetable productions he has been able to derive arguments in favour of his opinions. Some have also been furnished him by the phenomena which the processes of barking, cuttings, grafts, lop- ping, and other operations of culture present. There is not, so to speak, a single important fact of vegetation which he has not tried to wring under the rule of his doctrine; and his efforts, even when in certain cases some persons may have thought his conclusions too hasty, have never been unproductive. Explanations concerning each fact would carry us far. Let us dwel) only upon three points, which amongst so many other re- markable ones, merit more particularly to engage the attention of the Academy. At the base of a cauline bud of Dracena stript of its herbaceous envelope by maceration, there appears, if we may so express it, a kind of paw, a continuation of the superior ligneous fibres, which is fastened on the ligneous body of the stem, and elongates itself into threadlike fingers, numerous and divergent. These fingers are evidently minute vascular fasciculi. Would they have descended to the roots if the vegetation had not been stopt? This is very pro- bable. 376 Royal Socrety. The bud of a slip of Cissus hydrophora, stript of its bark, pre- sents at its base a ligneous network which partially clothes the inferior portion of the old wood, and escapes on every side in root. These two examples taken, the one in the monocotyledonez, the other in the dicotyledone, appear at first sight undeniable proofs of the solidity of the doctrine of M. Gaudichaud ; yet, notwith- standing, several phytologists, whilst they accept the facts, reject the theory. This is because the question is not so simple as it ap- pears. It is certain that it will not cease to be a subject of con- troversy until there shall be an agreement as to the physiological results of the process of grafting. The third point touches the scientific reputation of an excellent man, who sat here during more than forty years, and whose memory will be ever dear to us. Every one knows the work of M. Desfontaines on the stems of palms. A German phytologist, M.Hugo Mohl, treating of the same subject with more numerous and more varied materials, and all the resources of the science such as fifty years’ progress has made it, advanced, a short time ago, that the numerous ligneous fibres were not formed at the centre, but at the circumference ; and that it was in crossing the older fibres obliquely that they reached as far as the heart of the tree. From this fact he concluded that M. Desfontaines had deceived himself ; yet it is not so, although the observations of M. Mohl are perfectly accurate. The researches of M. Gaudichaud show that M. Des- fontaines has very well observed and described what he saw, and that M. Mohl, far from having overturned the work of this learned man, has rendered it more unassailable by completing it. The considerations set forth in this Report sufficiently make known the motives which have determined the commission to di- vide the prize between M. Gaudichaud and one of his competitors, M. Poiseuille, whose admirable works on the motion of the blood, render him for the third time worthy of a distinguished testimony of the esteem of the Academy. LXXIV. Proceedings of Learned Societies. ROYAL SOCIETY. (Continued from vol. viii. p. 553.) 1836. PAPER was read, entitled “ Additional Observations April 21. on Voltaic Combinations.” Ina letter addressed to Michael Faraday, Esq., D.C.L., F.R.S. Fullerian Professor of Chemistry in the Royal Institution, &c. By J. Frederick Daniell, Esq., F.R.S., Professor of Chemistry in King’s College, London. The author has found that the constant battery, of which he de- scribed the construction in a former communication to the Royal So- ciety, might be rendered not only perfectly steady in its action, but also very powerful ; as well as extremely efficacious and convenient for all the purposes. to which the common voltaic battery: is usually applied. With this view he places the cells which form the battery Royal Society. 877 in two parallel rows, consisting of ten cells in each row, on a long table, with their siphon-tubes arranged opposite to each other, and hanging over a smull gutter, placed between the rows, in order to carry off the refuse solution when it is necessary to change the acid. Having observed that the uniformity of action may be completely maintained by the occasional addition of a small quantity of acid, he is able to dispense with the cumbrous addition of the dripping funnel ; an arrangement which admits with facility of any combination of the plates which may be desired. April 28.—On certain parts of the Theory of Railways; with an investigation of the formule necessary for the determination of the resistances to the motion of carriages upon them, and of the power necessary to work them. By the Rev. Dionysius Lardner, LL.D., F.R.S. . The author observes, in his prefatory remarks, that an extensive and interesting field of mathematical investigation has been recently opened in the mechanical circumstances relative to the motion of heavy bodies on railways ; and having collected a body of experiments and observations sufficient to form the basis of a theory, he purposes, in the present paper, to lay before the Society a series of mathematical formule, embodying the most general expressions for the phenomena of the motion of carriages on these roads. . The author begins by investigating the analytical formule for the traction of trains over a level line which is perfectly straight, and finds, first, the distance and time within which, with a given amount of tractive power, the requisite speed may be obtained at starting ; and also the point where the tractive power must be suspended, pre- vious to coming to rest. The excess of tractive power necessary to get up the requisite speed is shown to be equal to the saving of tractive power previous to a stoppage; and formule are given for the determi- nation of the time lost under any given conditions at each stop. The motion of trains in ascending inclined planes which are straight, is next considered ; and formule are given combining the effects of friction and gravity, in opposition to the tractive force. The cir- cumstances which affect every change of speed, and the excess of tractive force necessary, in such cases, to maintain the requisite - speed, are determined ; as well as the other circumstances already stated with respect to level planes. The friction of trains upon descending planes is next investigated; and an important distinction is shown to exist between two classes of planes; viz., those whose acclivities are inferior to the angle of re- pose, and those of more steep acclivities. A remarkable relation is shown to exist between the tractive forces in ascending and descenil- ing the first class of planes. For descending planes of greater acclivity than the angle of repose, the use of breaks becomes essentially re- quisite. The effect of these contrivances is investigated, as well as the motion of trains on the accidental failure of breaks. In any attempts which have been hitherto made to obtain the actual velocities acquired by trains of carriages or waggons under these circumstances, an error has been committed which invalidates Third Series. Vol. 9. No 55. Nov. 1836. 2Y 378 Royal Society. the precision of the results; the carriages having been treated as sledges moving down an inclined plane. ‘The author has here given the analytical formule by which the effect of the rotatory motion of the wheels may be brought into computation ; this effect, depending obviously on the amount of inertia of the wheels, and on the propor- tion which their weight bears to the weight of the waggon. The properties investigated in this first division of the paper, are strictly those which depend on the longitudinal section of the line, presumed to be straight in every part of its direction. There is, however, another class of important resistances which depend on the ground-plan of the road, and these the author next proceeds to determine. The author then gives the analytical formule which express the resistance arising,—/irst, from the inequality of the spaces over which the wheels, fixed on the same axle, simultaneously move ; secondly, from the effort of the flanges of the wheels to change the direction of the train; and thirdly, from the centrifugal force pressing the flange against the side of the rail. He also gives the formule necessary to determine, in each case, the actual amount of pressure produced by a given velocity and a given load, and investigates the extent to which these resistances may be modified by laying the outer rail of the curve higher than the inner. He assigns a formula for the de- termination of the height which must be given to the outer rail, in order to remove as far as possible all retardation from these causes ; which formula is a function of the speed of the train, the radius of the curve, and the distance between the rails. In the latter part of the paper, the author investigates the method of estimating the actual amount of mechanical power necessary to work a railway, the longitudinal section and ground-plan of which are given. In the course of this investigation he arrives at several conclusions, which, though unexpected, are such as_ necessarily arise out of the mechanical conditions of the inquiry. The first of these is, that all straight inclined planes of a less acclivity than the angle of re- pose, may be mechanically considered equivalent to a level, provided the tractive power is one which is capable of increasing and diminish- ing its energy, within given limits, without loss of effect. It appears, however, that this condition does not extend to planes of greater ac- clivities than the angle of repose ; because the excess of power re- quired in their ascent is greater than all the power.that could be saved in their descent ; unless the effect of accelerated motion in giving momentum to the train could properly be taken into account. In practice, however, this acceleration cannot be permitted ; and the uniformity of the motion of the trains in descending such acclivities must be preserved by the operation of the break. Such planes are therefore, in practice, always attended with a direct loss of power. In the investigation of the formule expressive of the actual amount of mechanical power absorbed in passing round a curve, it is found that this amount of power is altogether independent of the radius of the curve, and depends only on the value of the angle by which the direction of the line on the ground-plan is changed. This result, Royal Society. 879 which was likewise unexpected, is nevertheless a sufficiently obvious consequence of the mechanical conditions of the question. Ifa given change of direction in the road be made by a curve of large radius, the length of the curve will be proportionably great ; and although the intensity of the resistance to the tractive power, at any point of the curve, will be small in the same proportion as the radius is great, yet the space through which that resistance acts will be great in pro- portion to the radius: these two effects counteract each other; and the result is, that the total absorption of power is the same. On the other hand, if the turn be made by a curve of short radius, the curve itself will be proportionately short ; but the intensity of the resistance will be proportionately great. In this case, a great resistance acts through a short space, and produces an absorption of power to the same extent as before. } In conclusion, the author arrives at one general and comprehensive formula for the actual amount of mechanical power necessary to work the line in both directions ; involving terms expressive, first, of the ordinary friction of the road ; secondly, of the effect of inclined planes, or gradients, as they have been latterly called ; and, thirdly, of the eftect of curves involving changes of direction of the road, the velocity of the transit, and the distance between the rails ; but, for the reason already stated, not comprising the radii of the curves. Although the radii of the curves do not form a constant element of the estimate of the mechanical power necessary to work the road, nevertheless they are of material consequence, as far as regards the safety of the transit. Although a short curve with a great resistance may be moved over with the same expenditure of mechanical power as a long curve with a long radius, yet, owing to the intensity of the pressure of the flange against the rail, the danger of the trains run- ning off the road is increased : hence, although sharp curves cannot be objected to on the score of loss of power, they are yet highly ob- jectionable on the score of danger. In the present paper, the author has confined himself to the ana- lytical formule expressing various mechanical effects of the most general kind; the coefficients and constants being expressed merely by algebraical symbols: but he states that he has made an extensive se- ries of experiments within the last few years, and has also procured the results of experiments made by others, with a view to determine the mean values of the various constants in the formule investigated in this paper. He has also, with the same view, made numerous ob- servations in the ordinary course of transit on railways; and he an- nounces his intention of soon laying before the Society, in another paper, the details of these experiments, and the determination of the mean values of these various constants, without which the present investigation would be attended with little practical knowledge. A paper was also read, entitled ‘‘ Register of the State of the Barometer and Thermometer kept at Tunis, during the years 1829, 1830, 1831 and 1832.” Presented by Sir Thomas Reade, His Majesty's Agent and Consul General at Tunis. Communicated by P. M. Roget, M.D., Sec. R.S. 2Y¥2 380 Royal Society. The observations here registered are those of the thermometer at 9 a.m., at noon, and at 6 p.m., and the points of the wind, and height of the barometer for each day of the abovementioned years. May 5.—A paper was in part read, entitled ‘‘ On the Optical Phe- nomena of certain Crystals." By Henry Fox Talbot, Esq., F.R.S. See our last Number, p. 288. May 12.—The reading of Mr. Talbot’s paper was concluded. May 19.—A paper was read, entitled, “On the valuation of the mechanical effect of Gradients on a line of Railroad.” By Peter Barlow, Esq., F.R.S. The exact amount of the influence of ascents and descents occurring in the line of a railway on the motion of a load drawn by a locomotive engine having been differently estimated by different persons, the au- thor was induced to investigate the subject. A few observations are premised on the erroneous assumptions which, he conceives, have in general vitiated the results hitherto deduced. The first of these is that the expenditure of power requisite for motion is equal to the resistance to traction; whereas it must always greatly exceed it. No account, he remarks, has been taken of the pressure of the atmosphere on the piston, which the force of the steam has to overcome before it can be available as a moving power. Another source of error has been that the statical and dynamical effects of friction have been confounded to- gether ; whereas they are the same in amount only when the body is put in motion by gravity ; but not when it is urged down an inclined plane by an extraneous force. In the latter case these effects are no longer comparable ; friction being a force which, in an infinitely small time, is proportional to the velocity, while that of gravity is constant at all velocities ; or, in other words, the retardation from friction is pro- portional to the space described, while that from gravity has reference only to the time of acting, whatever space the body may pass over in that time. It is an error to assume that the mechanical power of the plane is equivalent to a reduction of so much friction ; forthe friction down the inclined plane is the same as on a horizontal plane of the same length, rejecting the trifling difference of pressure; and the whole retardation in passing over the plane, or the whole force required to overcome it, is the same at all velocities, and by whatever force the motion is produced ; but the assisting force from gravity is quite inde- pendent of the space or of the velocity. In the investigations which the author has prosecuted in this paper, he assumes that equal quantities of steam are produced in the same time at all velocities ; and he adopts for his other data, those given by Mr. Pambour in his Treatise of Locomotive Engines. He deduces a formula from which, the speed on a level being given, we may compute the relative and absolute times of a train ascending a plane ; and con- sequently also the ratio of the forces expended in the two cases ; or the length of an equivalent horizontal plane ; that is, of one which will require the same time and power to be passed over by the loco- motive engine as the ascending plane. . The next objects of inquiry relate to the descent of trains on an in- clined plane, and comprise two cases ; the first; that when the power Royal Society. 381 of the engine is continued without abatement; and the second, that when the steam is wholly excluded, and the train is urged in its de- scent by gravity alone. ‘The author arrives at the conclusions, that in the first of these cases, when the declivity is one in 139, the velocity, on becoming uniform, will be double that in a horizontal plane: and that for a declivity of one in 695, the uniform velocity of descent will be one fifth greater than on the horizontal plane ; and this, he ob- serves, is perhaps the greatest additional velocity which it would be prudent to admit. A plane of one in 695 is therefore the steepest de- clivity that ought to be descended with the steam-valve fully open; | all planes with a declivity between this and that of one in 139 require to have the admission of steam regulated so as to modify the speed, and adjust it to considerations of safety ; and lastly, all planes of a greater slope than this last require, in descending them, the application of the brake. A paper was also read, entitled, ‘‘ On the application of Glass as a substitute for metal balance-springs in Chronometers."”’ By Messrs. Arnold and Dent. Communicated by Francis Beaufort, Esq., Captain R.N., F.R.S., Hydrographer to the Admiralty, In their endeavours to determine and reduce the errors arising from the expansions of the balance-spring of chronometers consequent on variations of temperature, the authors came to the conclusion that there exist certain physical defects in the substances employed for its construction, beyond the most perfect mechanical form that can be given to it, which interfere with the regularity of its agency: so that however exquisite may be its workmanship, and however complete its power of maintaining a perfect figure when in different degrees of tension, yet the imperfect distribution of its component parts may give rise to great incorrectness in its performance. Hence the balance- spring not only sheuld be made of a substance most highly elastic, but its elasticity should not be given to it by any mechanical or che- mical process: asa body in motion, it should be the lightest possible ; and, as far as the case admits of, it should be free from atmospheric influence. Glass suggested itself as the only material possessing, in the greatest degree, all these desirable properties. Its fragility, al- though apparently a great objection to its employment, was found, on trial, to constitute no obstacle whatever ; for it was found to possess a greater elastic force than steel itself, and thus to admit of greater amplitude in the arc of vibration. It was first propused to ascertain how fara glass balance-spring would sustain low temperatures ; and it was found by experiment that it resisted completely the effects of a cold as great as that of + 12° of Fahrenheit’s thermometer ; thus satisfactorily removing any objection which might be brought against its use from its supposed fragility in these low temperatures. The next object of solicitude was to deter- mine whether it would withstand the shock arising from the discharge of cannon in the vicinity; and its power of resisting concussions of this nature was fully established by experiments made with this view on board H.M.S. Excellent at Portsmouth, On comparing the performance of glass balance-springs with me- tallic ones, when the temperatures were raised from 32° to 100°, it 382 Geological Society. was found that while the loss in twenty-four hours in the gold spring was 8™ 45, that of steel 6™ 258, and that of palladium 2™ 315, that of a glass spring was only 40°. These differences the authors ascribe principally to the different degrees in which the substances had their elasticity reduced by an increase of temperature. As glass was thus found to suffer a much smaller loss of elasticity by this cause than metals, they proceeded to construct a glass balance suited to the cor- rection of the small error still occasioned by this cause, employing a glass disc for this purpose. The compensation being completed, they next tested the isochronism of the glass spring, and it proved to be as perfect as any metallic spring. Chronometers thus constructed are now in course of trial at the Royal Observatory. In common with all other instruments of the same kind they have shown a disposition to progressive acceleration, the cause of which is but little known, but which appears to be influenced by the action of the air. GEOLOGICAL SOCIETY. (Continued from vol. viii. p. 580. April 13.—A memoir on the Geology of Coalbrook Dale, by Joseph Prestwich, Jun., Esq., was commenced. April 27.—The memoir on the Geology of Coalbrook Dale; by Joseph Prestwich, Jun., Esy., began on the 13th of April, was concluded. In a paper read before the Society in February 1834, Mr. Prest- wich gave an account of some of the principal faults of this coal-field, and in the present memoir describes fully the extent and physical features of the district, the formations of which it consists, the dis- locations not previously noticed, the superficial detritus or drift, the organic remains, and the inferences which the author conceives may be drawn from the facts enumerated. In the first place, how- ever, he acknowledges the assistance which he has received from Mr. Murchison, Mr. Anstice of Madeley, and the gentlemen connected with the coal-works ; he also acknowledges the aid which he has derived from Mr. Arthur Aikin’s labours in the same district. The coal-field is bounded on the east by a slightly undulating line ranging from Lilleshall to Bridgenorth ; on the north-west by a line nearly coincident with the main road from Lilleshal! to Watling-street, near Wellington, and thence by the Wrekin; on the west the boun- dary is broken by the gorge of the Severn, but is formed, in part, by the elevated ridges of Benthall and Wenlock ; and on the south-east it is defined by the road from Much Wenlock to Bridgenorth. The area thus circumscribed consists of a platform raised about 400 feet above the Severn at Madeley, or 500 above the level of the sea; the surrounding country seldom rising to a height exceeding 350 feet. It is intersected by numerous picturesque glens, including the cele- brated defile through which the Severn flows at the Iron Bridge, and is traversed by several low hills, the most elevated of which is about 746 feet above the level of the sea; but the Wrekin, which forms part of the north-western boundary, rises to the height of 1320 feet, The formations of which the district consists are, commencing with the oldest, Ist, some members of the Lower Silurian rocks; 2ndly, the Wenlock and Ludlow rocks, belonging to the Upper Silurian sy- Geological Society. 383 stem; 3rdly, the old red sandstone ; 4thly, carboniferous limestone; 5thly, coal measures ; 6thly, new red sandstone ; and, 7thly, trap. In describing the formations subjacent to the old red sandstone, Mr. Prestwich states that he owes his knowledge of their order of su- perposition entirely to the previous labours of Mr. Murchison, and’ that unassisted by them it would have been impossible for him to have- determined correctly their relative antiquity. Ist. The lower Silurian rocks consist of quartzose grit succeeded by- micaceous flags, which are overlaid by a coarse-grained sandstone alternating with beds of light grey clay. They occur on the flanks of the Wrekin and Arcol Hills. 2ndly. The Wenlock rocks are composed, in the lower part, of beds of shale, and in the upper of limestone abounding with organic re- mains. They form the escarpment of Wenlock and Benthall Edges, Lincoln Hill, &. The Ludlow rocks consist of three divisions: the lowest being formed of grey-coloured, soft, calcareous sandstones and shales; the middle of very thin beds of light grey and brown limestone; and uppermost of sandstones. They are stated to occur at Much Wenlock and Wyke, also near Apley, in the Meadow-pits and in several other pits in Broseley parish ; likewise between Dean and Willey, &c. 3rdly. The old red sandstone skirts the southern parts of the coal- field, and consists of beds of dark red marl alternating with-dark, mi- caceous sandstones. 4thly. The carboniferous limestone appears on the south of Little Wenlock, at Steeraways and Lilleshall Hills, and presents thin beds of argillaceous limestone and shale. Sthly. The coal measures consist of the usual alternations of shale, sandstone, and coal, amounting at the Madeley Meadow pits to 135 beds, having an aggregate thickness of about 250 yards. The first 70 or 80 beds are light grey, yellow, or red; the succeeding 20 are nearly black, and the underlying are mostly light-coloured. These distinctions are general, but not universal. In the uppermost part of the series clays and soft calcareous sandstones predominate ; in the: middle argillaceous sandstones and indurated clay ; while in the lowest part fine hard sandstones. The upper coal seams are thin, generally sulphurous, widely separated, and extremely irregular, but the lower are nearer together, and are persistent throughout the field. The average thickness of the seams is about 3 feet, and the number in different pits varies from 1 to 16. The following table contains the aggregate thickness of the seams and the number at each of the loca- lities mentioned : Yards. ft. in, Number of beds. Maghey :. oj. | POO Os. POH EE Le 16 Sned’s Hill..... PBF 2ae2, 22 .0G,.. s 12 Malmslee ...... VEHOMTG. P2552. 2 13 Langley........ ll 2°6 ARR 11 Dawley’ .'./ctae'is REO OI) R252, 24 16 Lightmoor,..... FS 712. Oa. in AURRY 17 Madeley ....... 10.) DB PO eS 24 BUGEOUN ei ean cry 4G Ree ewe ae 13 384 Geological Society. . In these pits the measures are fully developed, and consequently . the variations may be explained by the thinner beds not having been . equally included. In the Madeley list every thin seam is given. The shales and sandstones vary greatly in their characters, though the former are said to be more uniform than the latter, and to contain layers of argillaceous carbonate of iron. A bed of freshwater lime- stone occurs in the upper part of the measures, at Inet, the Frog's Mill near Nordley, and at Tasley. It is very hard, has a fine con- choidal fracture, and varies in thickness from one to two yards. A minute accountis then given of the changes presented at different pits, and it is shown that the thinning out of the strata of sandstone and shale is frequently of great advantage to the miner by bringing into contact, beds of coal, which would otherwise be separated many feet. Carburetted hydrogen is disengaged in greater abundance from the lower than from the upper measures, and in greatest quantity on commencing a new work, especially on approaching a fault, when large masses of coal are constantly blown off the main beds with loud reports. Carbonic acid gas is rarely found in a pit at work, and Mr, Prestwich suggests that the quantity sometimes noticed may have been accumulated in adjacent old pits. The mineral contents of the coal measures are confined to the ar- gillaceous carbonate of iron, sulphuret of iron, sulphuret of zinc and petroleum. The celebrated spring, which once yielded more than a hogshead a day, produces now only a few gallons a week ; but another abundant spring has been discovered, and considerable quantities of petroleum have been obtained in working the Dingle pit. Titanium is found in considerable quantities in the hearthstones of the old furnaces often beautifully crystallized, but in greatest abundance in a massive state. In analysing some crystals of sulphuret of zinc found in the coal measures the author detected titanic acid. 6thly. New red sandstone.—Only the lower divisions of this forma- tion occur in the immediate neighbourhood of Coalbrook Dale, flank- ing the eastern and north-western sides of the field, and in some places abutting against the dislocated edge of the coal measures, They con- sist of clay, marl, and sandstones, overlaid by calcareous conglo- merates, to which succeed coarse sandstone, marls, and other conglo- merates. The lowest beds pass conformably into the coal measures, the line of distinction being chiefly distinguishable by the change in the colour ; but some of the vegetable remains of the coal may be, though rarely, detected in the sandstone series. Mr. Prestwich is of opinion that there is a want of conformity between the lower and upper systems of the new red sandstone series. 7thly. Trap rocks.—The greater portion of the Wrekin, Arcol, Mad- dox, and Lilleshall Hills, &c. are composed of greenstone, felspar rocks, and amygdaloid. Smaller bosses also rise to the surface at various points within the coal-field, and others have been discovered in the deep workings ; but it is worthy of remark that no trap has been no- ticed in any of the crevices or fissures connected with the faults. The trap does not appear to have charred the coal; but at New Hadley, at a point where a boss appears at the surface, the coal in its vicinity Geological Society. 885 loses its cohesion and becomes sooty, and the same change was no- ticed elsewhere near dislocations, though no trap was visible. Dislocations.—The author says that there is probably no coal-field of equal size in the kingdom so greatly shattered as that of Coalbrook Dale. The faults are most numerous and complicated where the measures are thinnest, the miner in those parts rarely proceeding 20 yards without interruption, and frequently not more than two or three ; but when so close together the dislocations are small in effect and ex- tent, and are connected with others of greater magnitude. The larger faults tilt the strata in various directions, but have ge- nerally a parallelism of strike, and deviate but very slightly from a straight line. Sometimes the sides of the disjointed strata are in con; tact, when the edges of the beds of coal and shale have a shining stri- ated surface, but at others the sides are separated several yards, the interval being filled with the debris of the strata. The inclination of the principal faults as well as of the minor, obeys no general law, and even in the same fault it occasionally varies from 45° to 90°. The difference of level on the opposite sides of the principal dislocations also varies considerably ; thus the Lightmoor fault, at Malmslee and Old Park produces a difference of level of 600 or 700 feet, but at Sned’s Hill of only 300, and a branch of it does not affect the strata more than 50 or 60 feet. In some instances the change of level is by steps or hitches, owing probably to unequal resistance, or a series of small dislocations. Another character of the large faults is their sub- dividing, more especially at the extremities—the subdivisions occa- sionally taking a direction at right angles to the main fault, but when they are numerous they diverge from it only a few degrees and extend but a short distance. The author then describes minutely the chief faults ; the two prin- cipal of which, bounding the field on the east and partly on the west, bring the disjointed edges of the coal measures in a level with those of the new red sandstone; and he afterwards gives a table of the minor faults, containing the name of each fault with its direction, extent, average angle of inclination, breadth, fall, the greatest difference of level produced by it, and the localities at which the difference of level varies ; and from the phenomena presented by the faults, and the fact that the field is a platform raised above the level of the sur- rounding country, the author infers that the coal-field has been ele- vated above its original position ; he also adds that the contortions of the beds are not of any great magnitude. Superficial detritus or drift —Thick beds of gravel and sand cover a Jarge portion of the surface, and are considered by the author as con- sisting of two distinct deposits. The lower, which is of local occur- rence, though from 20 to 50 feet thick, consists of fine-grained red sand, containing beds of small angular pebbles of the adjacent rocks, and thin, distinct seams of marl or clay. Imbedded in the sand are frequently found masses of coal, some of them six feet in diumeter, The upper deposit is composed of rolled pebbles of rocks, composing the coal-field and its boundaries, imbedded in coarse reddish sand. Its distribution is more regular than that of the lower division; and Third Series. Vol. 9. No. 55. Nov, 1836. 22 386 Geological Society. it is distinguished by the abundance of fossils derived from the Dudley limestone and the coal measures, as well as the presence of marine shells of existing species. Organic remains.—The fossils of the coal measures are described with great detail, as well as the phenomena of beds containing marine remains, alternating with others in which freshwater shells and land plants occur; and a comparison is made with the Ganister coal-field, in which similar alternations have been noticed. The following are the principal points detailed in the paper respecting these alternations at Coaibrook Dale. The lowest part of the coal measures presents nu- merous beds of sandstone and shale, with seams of good coal; some of the beds containing in abundance vegetable remains, occasionally associated with Unios. To these succeed the bed called the penny iron- stone, in which has been found a few vegetable remains and casts of Unios and Cyclades, but great abundance of marine remains belong- ing to the genera Producta, Spirifer, Ammonites, Nautilus, Bellero- phon, Conularia, Euomphalus, Pecten, Orbicula, Terebratula, Venus, Asaphus, and Pentacrinites ; remains also of fishes, namely, the Megal- ichthys Hibbertii and Gyracanthus formosus. The next series of beds, consisting of the usual alternation of sandstone, shale, and coal, in- close vegetable remains and Unios. Upon these repose a stratum of micaceous shale, containing ironstone nodules in which have been found land plants, Unios in considerable quantities, remains of the Me- galichthys and Gyracanthus, and Trilobites of a distinct genus. This singular stratum is surmounted by a series, of great thickness, of the usual coal measures, in which organic remains and land plants have been observed, and is succeeded, in two localities, by the Chance penny-stone, in which Productus scabriculus occurs in vast abundance. The uppermost beds of the series, consisting of many thick beds of sandstone with layers of shale and one seam of coal, are almost de- stitute of organic remains. The distribution of the fossils is extremely irregular in different parts of the coal-field, being most persistent in the lower beds; and though they are most commonly found in the ironstone nodules, yet they sometimes occur in the sandstones and shales adjacent to the coal seams. In the concluding part the author reviews the facts detailed in the memoir, and draws the inferences which he conceives they warrant. Ist. Mr. Prestwich is of opinion that the alternations of freshwater shells with marine remains, do not prove as many relative changes of land and sea; but that the coal measures were deposited in an estu- ary, into which flowed a considerable river, subject to occasional freshes ; and he conceives that this position is supported by the fact of frequent alternations of coarse sandstones and conglomerates with beds of clay or shale; and for the same reason he is of opinion that the vegetable remains did not grow where they are found. 2ndly. After recapitulating the evidence in support of the protru- sion of Coalbrook Dale through once continuous overlying forma- tions, he calls attention to the important inquiry whether there may not be buried beneath the new red sandstone districts other conside- rable coal-fields, which are unknown, because they have not been sub- - Geological Society. 387 ject to disturbing agents similar to those which exposed the district under review. Lastly. With respect to the agents which have modified the surface of Coalbrook Dale, the author is of opinion that it was denuded, in part, while beneath the level of the ocean ; that the lower bed of de- tritus, containing angular gravel and large masses of coal, proves a sudden and short cataclysm ; while the upper beds of rounded gravel, containing recent shells, indicate the long-continued action of a body of water, since the existence of the present Testacea of our coasts. A letter from R. W. Fox, Esq., addressed to Sir Charles Lemon, Bart., M.P., F.G.S., “On the Formation of Mineral Veins,” was then read. Mr. Fox is of opinion that mineral veins were originally fissures probably caused by changes in the earth’s temperature; that they were small at first and gradually increased in their dimensions ; and that the mineral contents progressively accumulated during the whole period of the development of the fissures ; and as changes in the earth’s temperature might produce changes in the direction and intensity of the terrestrial magnetic curves, he conceives that electricity may have powerfully influenced the existing arrangement of the contents of these fissures. Copper, tin, iron, and zinc, in combination with sulphuric and muriatic acids, being very soluble in water, Mr. Fox says, they would in this state be capable of conducting voltaic electricity; and as the rocks forming the walls of the veins contain different salts, they would be in opposite electrical conditions, and hence currents would be generated and readily transmitted through the fissures, and in time the metals would be separated from their solvents and deposited in the veins. But, on the known principles of electro- magnetism, Mr. Fox adds, it is evident that such currents would be more or less influenced by the magnetism of the earth ; and there- fore that they would not pass from north to south or from south to north as easily as from east to west, but more so than from west to east. The author then offers some observations relative to the production of sulphurets from the decomposition of the metallic sulphates ; and explains how fissures, gradually widening, would be successively filled, and would account for veins occurring within veins; he offers some remarks also on the greater productiveness exhibited at the points where veins pass from one formation to another, and is of opinion that the fact may be explained by supposing the rock in which the vein is productive to have been electro- negative. In conclusion Mr. Fox states, that if in other parts of the world veins may be found to deviate from an east and west direction much more than they do in England, the apparent discrepancy may be ex- plained by the rocks having yielded more easily in one direction than in another, and from a difference in the direction of the magnetic me- ridian in different countries, as well as from the probability that it has varied greatly at different epochs. 2Z2 388 xoological Society. ZOOLOGICAL SOCIETY. April 12.—Mr. Bennett directed the attention of the Meeting to a living specimen of the brush-tailed Kangaroo, Macropus penicillatus, Gray, which had recently been added to the Menagerie ; having been presented to the Society by Captain Deloitte, Corr. Memb. Z. S. He remarked particularly on the peculiarity of its actions, as com- pared with those of the typical Kangaroos; and especially on the ease with which it vaults from the ground to any slight ledge, on which it remains perched, as it were, with its tail extended behind it: the tail, im fact, appearing to be in no respect aiding in the pro- gression of the animal. Referring to some observations which he had made on the exhi- bition of askin of the same species, at the Meeting of the Society on January 13, 1835, (Lond. and Edinb. Phil. Mag. vol. vii. p. 67,) he stated it to be his intention to reduce into order his various re- marks on the subject, and to accompany them by a figure of the animal taken from the living specimen. Mr. Owen read the following notes of the morbid appearances ob- served in the dissection of the specimen of the Chimpanzee, Simia Troglodytes, Linn., which lately died at the Gardens; and respecting the habits and faculties of which some observations by Mr. Broderip were read at the Meeting of the Society on October 27, 1835. (Lond. and Edinb. Phil. Mag., vol. viii. p. 161.*) * Adhesions of the abdominal viscera to the parietes of the cavity existed in many parts, but more especially of the ascending colon and cecum on the right side. On separating these adhesions a purulent cavity was exposed, with which the zlewm, near its ter- mination, communicated by an ulcerated aperture about half an inch in diameter. An abscess also existed between the lower end of the cecum and the peritoneum, and the whole of the fundus of the cecum was destroyed by ulceration, together with part of the ver- miform process ; the remainder of which was much contracted and shrivelled, and was found adhering to the sound part of the cecum. The efficiency of the adhesive process in repairing, or at least pre- venting, the immediate evil consequences of a solution of continuity in the intestinal parietes, was remarkably exemplified in this instance ; for notwithstanding the extent to which this had taken place, not a particle of the alimentary matters had escaped into the general cavity of the abdomen, nor was the mischief suspected until the ad- hesions were separated. “ On laying open the z/ewm it appeared that the original seat of the ulcer had been a cluster of the aggregated intestinal glands; similar patches in the immediate neighbourhood were in a state of ulceration ; and others were enlarged, or more than usually con- spicuous, as they were situated farther from the seat of the disease. * An abstract of Mr. Owen’s paper on the comparative osteology of the Orang and Chimpanzee appeared in Lond. and Edinb. Phil. Mag., vol. vi. p. 407. Roological Society. 389 In the commencement of the colon, the solitary glands presented a state of enlargement and ulceration, and here and there an inor- dinate vascularity ; but in the general track of the intestinal canal traces of recent or active inflammation were very few. The con- dition of the mucous membrane of the intestines closely resembled that which is so generally observed in phthisical subjects; here, however, the strumous matter was not developed in the lungs, but was confined to the mesenteric glands and spleen. All the mesenteric glands were more or less enlarged by a deposition of caseous matter : two, which are usually found adhering to the ter- mination of the ileum, were even in a state of suppuration and ul- ceration, so that the parietes of the gut may have been attacked by the ulcerative process on both sides,—from without by that com- mencing in the mesenteric glands,—from within by that of the glan- dule aggregate: it was most probably, however, progressive from the latter point. “The spleen was greatly enlarged, measuring 5 inches long and 4 broad, with numerous small scattered tubercles, none exceeding half an inch in diameter. Its substance was firm, but so disorganized as to enable it to fulfil in a very slight degree the functions of a reservoir of venous or portal blood. “ The liver was enlarged about one third beyond its usual size, and was of a pale colour; but upon a close inspection it presented no other morbid appearance than a congested state of the portal veins: a condition frequently associated with strumous viscera, and which was very well marked in this case, and perhaps dependent on the diseased state of the spleen. The gall-bladder contained thick but healthy-coloured bile. “The stomach seemed free from disease; but had a large perfo- ration, the margins of whch showed that it had resulted from the post-mortem action of the gastric secretion. “The pancreas was healthy. “Tn the chest there were no adhesions. The heart was healthy. The lungs were somewhat firmer than usual, and the air-passages contained an unusual quantity of fluid secretion, in some parts stained with blood; but none of the air-cells had been obliterated by either inflammatory action or strumous deposition: there had been recent subacute inflammation of the mucous lining of the air-passages, but nothing more. “No Entozoa were met with in the dissection; although the ali- mentary canal was carefully searched for them. “The brain and its membranes were healthy. “‘ With respect to the organization of the Chimpanzee, so far as the dissection was carried, the parts corresponded with the de- scriptions given by Tyson in his ‘Anatomy of a Pygmie’ ; and by Dr. Traill in the ‘Wernerian Transactions,’ vol. iii. “The tunica vaginalis testis, which communicates with the ab- domen in the Simia Satyrus, was here a completely closed or shut sac, as in the human subject.” 390 Soological Society. “Descriptions of some Species of Shells apparently not hitherto recorded: by W. J. Broderip, Esq., V.P.Z.S., F.R.S., &c.” were read. The reading of the communication was accompanied by the exhibition of specimens of the several species referred to in it: viz. Sronpytus albidus; Votura Beckii and Concinna; Conus Adam- soni; Purpura Gravesii; and Buxinus Crichtoni, inflatus and Pusio. The characters, &c., of these shells are given in the “ Proceed- ings” of the Society, No. XL,, from which we retain the following : Buuinus Cricutont. Bul. testa fusiformi, longitudinaliter costatd et corrugatd, costis rugisque validis, subalbidd maculis spadiceis notatd ; labio rosaceo-violaceo, labro pallidiore, expanso, subreflexo: long. 3 (circiter), lat. 12 poll. Hab. ad Ambo juxta Huanuco Peruvie. Mus. Brod. This curious shell, which at first sight reminds the observer of Bulinus Labeo, Brod., (Zool. Journ., vol. iv. p. 222,) brought home by Lieut. Maw, R.N., and presented by him to the Zoological Society of London, from whose Museum it has been stolen*, differs strongly from it, as will be seen by a reference to the figure in the ‘ Zoolo- gical Journal’ which is very accurate, excepting that the longitudinal lines in the engraving are rather too strongly expressed. The apex of the shell under description, the only specimem I ever saw, is broken, and its actual lengthis 2 inches and 3. It will be observed that the specimen is notched at the base, but I suspect that this arises from accidental distortion. April 26.—A Note was read, addressed to the Secretary by J. B. Harvey, Esq., Corr. Memb. Z.S., and dated Teignmouth, April 24, 1836. It referred to a series of specimens of Rostellaria Pes Pelicani, Lam., presented by the writer to the Society, and which he regards as interesting on account of the evidence afforded by them of the curious fact, that in the shells of this species the outer lip is most thickened at a time antecedent to the full development of the shell; absorption of the incrassated part of the lip taking place as the animal advances inage. ‘‘ This series,’ Mr. Harvey remarks, ‘clearly shows that the shell, when not more than one half or three quarters grown, is much thicker than when all the processes are perfected: and that, when each process has a groove or channel in it, the shell is quite thin, and has arrived at its full period of growth.” The shells referred to in Mr. Harvey’s letter were exhibited. Characters were read of the Vespertilionide observed in the central region of Nepal; being a communication transmitted to the Society by B. H. Hodgson, Esq., Corr. Memb. Z.S. They have already been published in the‘ Journal of the Asiatic Society of Calcutta’, for De- cember, 1835, vol. iv. p. 699. * This certainly was, and I believe (wherever it may be) is, the only spe- cimen in Europe. It was in remarkably fine condition. Soological Society. 391 The following are the species characterized : Rhinolophus armiger, Hodgs. Rhin. tragatus, Ej. Pteropus leucocephalus, E}. Pter. pyrivorus, Ej. Vespertilio formosa, E}. Vesp. fuliginosa, 1). Vesp. labiata, Ej. Mr. Hodgson’s characters of these species are accompanied by re- marks on the habits of the several genera of Bats which are repre- sented by them in the district in which they occur. A second communication by Mr. Hodgson was read, which has also been published in the ‘Journal of the Asiatic Society of Cal- cutta’ (vol. iv. p. 648.) It was entitled ‘‘ Specific Name and Cha- racter of a New Species of Cervus, discovered by Mr. Hodgson in 1825, and indicated in his Catalogue by the local name of Bahraiya.” The animal to which this paper refers is regarded by Mr. Hodgson as constituting an important link in the chain of connexion between the Deer of the Rusan and of the Elaphine groups : possessing in the numerous snags into which the summit of its horns are divided one of the principal characteristics of the latter group; but agreeing with the former in the absence of any median process on the stem of the horn, and in the singleness of the basal antler. In stature and aspect the species is intermediate between Cervus Hippelaphus, Cuv., and Cerv. Elaphus, Linn. Its general resemblance to the latter is indicated in the trivial name assigned to it by Mr. Hodgson, that of Cerv. Elaphoides. It is referred to in his ‘Catalogue of the Mammalia of Nepal’ (Proceedings, part il. p. 99.) under the name of Cerv. Bahruiya, Hodgs. Specimens were exhibited of numerous species of British Fishes, forming part of the collection of Mr. Yarrell. They consisted of dried preparations of rather more than one half of the skin of each individual: a mode of preservation peculiarly adapted, as Mr. Yar- rell remarked, for travellers over land; specimens so prepared occu- pying but little space, and being consequently as portable as dried plants. An incision is made in the first instance round one side of the fish, at a short distance from the dorsal and anal fins, and the whole of the viscera and flesh are removed, so as to leave only the skin of the other side with the vertical fins attached to it, and with rather more than one half of the head: the loose edge of skin left from the side in which the incision has been made, is then fastened by means of pins to a piece of board, so as to display the entire side of the fish which it is intended to preserve, and it is then hung up to dry in an airy but shady situation. The more rapidly the drying is completed, the more effectually will the colours be preserved. As soon as the skin is dried it is varnished; and the loose edge of the skin on that side from whence the operation of removing the flesh has been effected is trimmed off with a pair of scissors, as being no longer useful. The preparation is then completed, and consists of the entire skin of one side of the fish, of the vertical fins, and of ra- 392 Intelligence and Miscellaneous Articles. ther more than one half of the head, the latter being important for the preservation of the vomer, so as to show the absence or presence of teeth on that bone, and their form. All the essential characters of the fish are consequently preserved, if care be taken that the skin be so attached to the board on which it is dried, as to retain its ori- ginal dimensions of length and depth: the due thickness of the fish may be secured in the preparation, if it be considered desirable, by inserting beneath the skin, when extending it on the board, a suffi- cient quantity of prepared horse-hair. After explaining the mode which he had adopted in the prepara- tion of the specimens exhibited, Mr. Yarrell made various remarks on those which he regarded as the most interesting among them ; and particularly on a series of Trout and Charr from different loca- lities, and varying in colour according to situation, to season, and also, in some instances, to food. He then directed the attention of the Meeting to the specimens of the British species of Rays which formed part of the collection, and pointed out particularly the difference, as regards surface, which ob- tains in the sexes of many of these fishes; the skin of the female being, in every instance, comparatively smooth. He added also, by reference to these specimens, and to specimens of the jaws exhibited for that purpose, an explanation of the differences which exist, in adult individuals, in the teeth of the sexes respectively ; those of the male becoming exceedingly lengthened and pointed, while in the fe- male they retain very nearly their original flattened surface: the form of the teeth, equally with the armature of the surface, constituting in these fishes a secondary sexual character, although both the one and the other have repeatedly, but erroneously, been considered as adapted for the establishing of specific distinctions. LXV. Intelligence and Miscellaneous Articles. EHRENBERG ’S FOSSIL INFUSORIA. DUJARDIN laid before the Philomathic Society of Paris, e some of the tripoli or polierschiefer of Bilin in Bohemia, to- gether with a microscope, by means of which it could be perceived that this tripolj is formed, as M. Brongniart has announced from the infor- mation of M. Ehrenberg, entirely of the siliceous remains of organized bodies, These bodies, all proceeding from the same living species, appear under two different forms: according as they are situated, trans- versely or perpendicularly, they are minute rings, or rectangles en échelle, with transverse bars corresponding to each ring: some of those bodies, viewed obliquely, show well the identity of some with others ; they originally formed articulated tubes, perfectly cylindrical, from 10 to 16 thousandths ofa millimetre in size, formed of contiguous rings, whose height is less by half, and which each have an extremely thin partition, as some broken rings show perfectly well; but, at the present time, we find an analogous structure only in the Diatome which are placed by many naturalists in the vegetable kingdom, but Intelligence and Miscellaneous Articles. 393 which have the shield more or less depressed, and each joint of which, instead of having a single partition, is closed at the two extremities. On the other hand, the Bacillaria have a prismatic shield, often streaked or furrowed, but without real partitions. M. Dujardin observes that the greater part of the tripolis in the mineralogical collections of Paris by no means present this character, and under the microscope only show grains of silex; and that the same is the case with regard to the silex of Saint Quen (silex nectique), as well as to the schists which envelope the menilite, which some German au- thors had referred to the polierschiefer. It would seem that the tri- poli or polierschiefer of Bilin, very different from the others, belongs to a very recent lacustrine deposit. That of Santa Fiora, which is mentioned in the letter of M. Brongniart as presenting also the cha- racter specified by M. Ehrenberg, seems also to be the product of a deposit of recent formation, which M. Dufrenoy considers as probably presenting some analogy with the siliceous deposits of the Geyser.— Société Philomathique de Paris, July 16. L’ Institut, No. 168. METEOROLOGICAL OBSERVATIONS MADE DURING THE SOLAR ECLIPSE OF MAY 15, 1836, AT GREENWICH, BY MR. W. R. BIRT. h m 11 15 Howard's fair-weather cumulus, forming on the vapour plane; motion N. by E. As the masses passed over the river they were seen to break into smaller patches, and the thinnest dissolved. Observatory Vane. 12 30 due E. The cumuli are now prevalent. 20 On NE Cumuli still prevalent, their motion being N.W. Considerable diminution of light. White glare in irregular patches noticed round the sun, and filling a circular space of about 40° in diameter. 310 S.E. White glare more evenly dispersed; at this time the wind suddenly shifted to S.E. and more white glare formed in irregular patches, Venus was now perceptible, and continued visible for about half an hour. The cumuli less numerous. 3 20 White glare more evenly dispersed; the cu- muli confined to a space of 40° round the sun, except a large mass to the §.W. under the sun. 3 30 S.E.byS. White glare still filling a space of 40°. A few masses of very thin cumuli before the sun, Motion N.W. 3 45 White glare not estimable. 4 0 Cumulus augmenting in the S.W. 4 10 Cumuli nearly gone. 4 15 Breeze freshening. 4 20 S.E. 4 35 SS.E 5 S.E Third Series. Vol. 9. No. 55. Nov. 1836. $A 394 Intelligence and Miscellaneous Articles. During the latter part of the eclipse, from 3 p.m., the upper cur- rent was steadily from the N.W. The most interesting portion of the observations is that relating to the white glare, which was evi- dently due to the diminution of heat. A beautiful stratum of czrro- cumulus passed over between{8 and 9 in the evening. I was not able to observe its motion. The white glare was very prevalent during the morning and forenoon, but the atmosphere was quite clear at the commencement of the eclipse. The above observations may be divided into four portions, namely, those previous to the commencement of the eclipse ; 2nd, from this time to 3 hours; 3rd, between 3 hours and 3 hours 45 minutes; and lastly, those taken after that period. The first period was charac- terized by considerable haziness in the atmosphere, which was the only modification of cloud observed until 11 hours 15 minutes, when cumulus began to form the haze; then gradually diminished as the cumuli increased, and when the eclipse commenced the sky was free from haze, but much diversified with cumuli, which were very prevalent, their motion being north by east, while the lower current was due east. The second portion was characterized by the prevalence of cu- mulus, with an otherwise clear sky. The third portion was the most interesting, as the effect of the eclipse on the state of the atmo- sphere was nowexhibited. The most striking feature consisted in the production of a white haziness that filled a space around the sun of about 40 degrees in diameter; this was first noticed at 3 P.M., and appeared evidently due to the diminution of temperature occasioned by the interposition of the moon. I have used the term white glare, by which Sir John Herschel designates the hazy appearance observed around the sun in his observations of the summer solstice, December 21 and 22, at the Cape, inserted in the Athenzeum of May 14th. This appearance continued visible until 3 hours 45 minutes, so that it dis- appeared about the same time after the greatest obscuration as it appeared previous to it: at the commencement of this portion of the observations the lower current was north-east, the upper current having varied to north-west ; during it the lower current changed to south-east, but the clouds kept moving steadily from north-west. Another interesting feature at this time was the clearing of the at- mosphere of clouds, similar to that which takes place on a fine sum- mer’s evening after a fine day similar to the present, when the fair- weather cumulus alone is observed : as the temperature declines, less moisture is exhaled from the surface, consequently no more cumulz are formed, and a clear evening follows. A precisely similar phe- nomenon was observed on the present occasion, but at a much earlier period : this was also probably due to the diminution of temperature. Nothing occurred to mark the fourth period, except a beautiful stratum of cirro-cumulus, the largest variety which was noticed : be- tween eight and nine in the evening it passed over rapidly; I did not particularly observe its motion, but it was from the western ho- rizon. Intelligence and Miscellaneous Articles. 395 ON A NEW SPECIES OF ACETATE OF COPPER. M. F. Wohler has found that the neutral acetate of copper will com- bine with another proportion of water than that which is contained in the common crystallized verdigris. This new salt is interesting in many respects : it forms large, beautiful, transparent crystals, of the same shade of blue as sulphate of copper, which at once serves to show that a difference exists between it and the common neutral acetate. When a crystal of this salt is heated to about 90° Fahr. it soon becomes opake and green like verdigris, without changing its exterior form, but by slight pressure is converted into a mass of small crystals of verdigris. This transformation is immedi- ately perceived by throwing a crystal into warm water, and the slower a crystal is heated the larger and more distinct are the small crystals of verdigris into which it is changed. This phenomenon exactly resembles the known changes of form which take place with- out change of composition, which have been observed in sulphate of magnesia, sulphate of zinc, &c., and it is for this reason that this salt of copper deserves attention ; for it shows that in phenomena of this kind we ought to be careful to distinguish between those cases in which change of form occurs without change of composition, and those in which the one is the cause of the other. The preceding phenome- non belongs to the latter class; for the change of colour and form is connected with the separation of four fifths of the water of crystalli- zation of this salt. This latter modification does not occur when the crystal remains entire and is become pseudomorphous, for the disengaged water remains inclosed between the new formation of small crystals ; and for the same reason, immediate analysis would show the same proportion of water to exist in it, as in the modified crystal. This circumstance might easily be overlooked, for when a crystal changed to green is exposed to the air, it gradually parts with the interposed water ; this quantity of water, although in itself small, may be detected by pressing one of the transformed crystals between blotting-paper, which will become damp, from the interposed water retained between the new formation of the small crystals of common verdigris. The quantity of water which the blue salt loses by its conversion into the green is 26°48 per cent. ; this is four times as much as that which is still retained by the resulting green salt, that is, the common crystallized verdigris. Thus the blue salt con- tains 33°11 per cent., or 5 equivalents of water ; it is very easily pre- pared by dissolving verdigris in warm, but not boiling, water acidu- lated with acetic acid, and crystallizing the solution.— Journ. de Phar- macie, July 1836. — FACTS RELATIVE TO THE HISTORY OF ATHER. Some time ago M. Liebig was led, from the results of an analysis of phosphovinate of barytes, to consider the acid of this salt as a com- bination of phosphoric acid and ether. A similar composition would naturally be assigned to the sulphovinates, but the experiments which were made to verify this supposition served only to show that by the 3A2 396 Intelligence and Miscellaneous Articles. aid of heat this class of salts lost a portion of their water without suffering decomposition. Here the matter rested, until M. Marchand discovered that the sulphovinates lose their water, with extreme faci- lity, at ordinary temperatures, when placed over sulphuric acid in va- cuo. It follows from his experiments that the sulphovinates of lime, barytes, and soda may be represented by the following formula : 2 So’ + Ba O (Ca O, NaO) + EO 4 2 Aq. And that, if we abstract, by means of the air-pump, the two equiva- lents of water which they contain, we then obtain a salt which is com- posed of 2 eqs. of sulphuric acid, 1 eq. of base, and | eq. of ether. Sulphovinate of potash does not contain any water of crystallization. M. Liebig has repeated the experiments of M. Marchand to verify their important results and to confirm them in a more complete man- ner ; but he does not admit the doubt that this chemist has raised, as to the formation of alcohol, when sulphovinate of potash is distilled with quicklime. This formation, which M. Mitscherlich has noticed in his treatise, is not only, he says, an accurate fact, but there is produced at the same time the oil of wine and combined hydrogen (Uhydrogeéne combiné) of Serullas. Thus, if we mix sulphovinate of potash with hydrate of lime and expose it to a heat of not above 392° Fahr., we only obtain alcohol, and the mixture does not blacken ; but if we use quicklime instead of its hydrate, distillation affords a liquid from which, when mixed with water, sulphate of oil of wine is precipitated ; and if from the beginning a strong heat has been applied, the mixture blackens, and there is olefiant gas obtained along with the alcohol and sulphate of oil of wine. The formation of the alcohol is easily explained by the composition of sulphate of oil of wine: this sub- stance consists of 2 eqs. of sulphuric acid, besides 8 C + 18H+O; and by adding to this formula an equivalent of alcohol, 4 C+ 12 H+20, we obtain 12C+30H+30, that is to say, 3 eqs. of ether. At the close of this investigation, M. Liebig relates the two following experiments, which are remarkable for their elegance. When a mixture of five parts of sulphovinate of lime and one part of acetic acid—such as is obtained from dry acetate of lead and sul- phuric acid—is distilled with a gentle heat, a large quantity of pure acetic ether is obtained. By distilling five parts of sulphovinate of potash with five parts of sulphuric acid diluted with one part of water, we obtain perfectly pure ether. Pure acetic ether is also procured by heating concentrated phosphovinic acid with acetate of potash.— Journ, de Pharmacie, Fev. 1836. HAS HEAT WEIGHT ? To the Editors of the Phil. Mag. and Journal of Science. GENTLEMEN, The question, “‘ Has heat weight ?” has been long matter of dis- pute, and it is not easy to answer those who contend, that if its weight be in the same ratio to that of hydrogen, as that is to the Intelligence and Miscellaneous Articles. 397 weight of platina, the most delicate balance would not turn with so light a load; besides, they would argue, there are many sources of minute error, which prevent the delicate experiment of ascertaining the supposed no change of weight, with change of heat, being de- cisive ; such as change of length of the arm of the balance, change in the specific gravity of the body heated or cooled, and other errors the exact amount of which cannot be ascertained. The sanre objection may be urged against the apparently decisive conclusion, derived from the fact that when given weights of hydrogen and oxygen are combined by combustion, the weight of the water is equal to the sum of the weights of the elements though very in- - tense heat is produced during the combination. It must, I think, be acknowledged that human experiment proves nothing more than that if there be any gravitating force it is extremely small. But nature tries the experiment for us on a scale of magnificence, which we may in vain attempt to imitate, for if heat have weight it must necessarily when in motion have momentum ; and if the velocity of radiant heat from the sun be equal to that of light, some momentum should be discoverable. But granting that the momentum is too small in amount to show itself on the small scale, it would be sure, did it exist at all, to increase the period of revo- lution of the planets. It has been proved that the planets revolve at such distances from the sun, and with such velocities, as that the centrifugal and attractive forces shall be equal, if the later force be inversely as the square of the distance. But if heat had any momentum, its particles, acting upon such large masses as the planets, must produce an evident effect by increasing their distances and periodic times. Now these are not increased ; there can then be no centrifugal force from this cause, heat can have no momentum, and therefore no weight. If it be objected to this conclusion that the ratio of attraction has been over-estimated, that it is sufficiently powerful to balance both the tangential force of revolution and the centrifugal force of the momentum of radiant heat ; I answer that this supposition, vio- lent as it is, would not remove the difficulty unless all the planets were of the same size and mass, or unless the sectional area of all were proportionate to the mass. The density, or rather rarity, of the resisting medium which has accelerated Encke’s comet, has not been ascertained, but it can hardly be such as to counterbalance the supposed centrifugal momentum of heat; for if the density be uniform, then the velocity of the planets through it should be proportionate to the decrease of the rays of heat, that is, inversely as the square of the distance from the sun. If the density be inversely as the square of the di- stance (supposing the medium analogous to an atmosphere), the ve- locity of the planets through it should be uniform: neither being in accordance with facts. Yours, &c. Manchester, Aug. 13, 1836. P. W. HoLuanp. 598 Intelligence and Miscellaneous Articles. DR. HUDSON’S REPLY TO DR. APJOHN’S PAPER INSERTED IN . THE PHILOSOPHICAL MAGAZINE FOR SEPTEMBER. In the course of September last we received from Dr. H. Hudson a reply, dated Stephen’s Green, Dublin, 10th September 1836, to Dr. Apjohn’s paper insertedin our Number for that month, accom- panied by aprivate note addressed ‘* To the Editors of the Philoso- phical Magazine,” and dated September 12th, requesting the inser- tion of the reply. We acknowledged the receipt of Dr. Hudson’s communication in the notice ‘‘ To Correspondents” on the wrapper of our last Number, for October, stating it to be “‘ under considera- tion”. Having now given it full consideration, we regret that from the very personal form which the controversy between Dr. Hudson and Dr. Apjohn has now, perhaps unavoidably, assumed, we feel called upon to terminate the discussion in our pages. We have no intention whatever, in doing this at the present juncture, to express any opinion on the merits of the subject ; but were Dr. Hudson’s reply to be inserted, Dr. Apjohn would have an equal claim to the publication of his rejoinder, and a controversy, in which nothing would be added to the progress of science, (for the points in dispute do not involve any principles which have not al- ready been fully explained in the original papers), might be conti- nued indefinitely, or we might be compelled to close it at some fu- ture stage. Dr. Hudson, however, is entitled to the most explicit record of the promptitude of his reply, and of his contradiction of Dr. Apjohn’s statements, on which account we have noted above the reception and date of his communication, and also inserted the pre- sent paragraph.—Epir. FUSELI’S PORTRAIT OF PRIESTLEY. It is not generally known that a portrait exists of Dr. Priestley, painted, when he was about fifty, by the celebrated Fuseli, which de- rives a value, not only from the interest of the subject, but from the faithfulness of the resemblance and the spirit and excellence of the execution ; as well as from the circumstance of its being almost the only portrait which the celebrated artist is known to have painted. That his powers were zeaiously employed on this picture may be in- ferred from the circumstance that it was undertaken at his own particular request, and presented to the common friend at whose house they occasionally met, Mr. Johnson, the Bookseller, St. Paul’s Church- yard, after whose death it was removed to the Library in Redcross Street. Mr. Turner has been for some time employed upon this portrait, and has produced an excellent engraving from it, for a number of gentle- men who have entered into a subscription for the purpose. He has succeeded in giving to this print, which is a very faithful copy of the Meteorological Observations. 399 picture, a powerful and pleasing effect; and the size is conveniently adapted either for the cabinet or the folio. Subscribers’ names are received by Mr. Richard Taylor, at the Office of the Philosophical Magazine, Red Lion Court, Fleet Street, where the copies (Proofs) will be delivered on application. A very few Proofs have been taken before the letters for those who may be desirous of possessing them. SCIENTIFIC MEMOIRS, selected from the Transactions of Fo- reign Academies of Science, and from Foreign Journals. Part II., just published, contains Researches relative to the Insects, known to the Ancients and Moderns, by which the Vine is infested, and on the Means of pre- venting their Ravages. By M. le Baron Walckenaer, Hon. Memb. of the Entomological Society of France. The Kingdoms of Nature, their Life and Affinity. By Dr. C. G. Carus, Physician to His Majesty the King of Saxony. Researches on the Elasticity of Bodies which Crystallize regularly. By Felix Savart. Researches concerning the Nature of the Bleaching Compounds of Chlorine. By J. A. Balard. On the Laws of Conducting Powers of Wires of different Lengths and Diameters for Electricity. By E. Lenz. Memoir on the Polarization of Heat. By M. Melloni. METEOROLOGICAL OBSERVATIONS FOR SEPTEMBER 1836. Chiswick.—Sept. 1. Very fine. 2. Overcast : stormy showers: clear and cold. 3.Fine. 4. Rain: fine. 5. Cloudy: very fine. 6. Stormy showers. 7.Fine, but cool. 8. Very fine. 9, Overcast : cloudy: rain at night. 10. Fine. 11. Cloudy: stormy at night. 12. Stormy showers: clear and windy at night. 13, Cloudy and cold: boisterous. 14. Cold haze: fine. 15. Fine. 16. Showery. 17. Fine: thunder showers. 18—20. Cloudy, and fine. 21. Cold and damp: fine. 22. Foggy : very fine. 23. Stormy and wet. 24,25. Fine. 26, 27. Hazy: fine. 28. Clear: heavy showers: fine. 29.Rain. 30. Clear and cool: stormy showers, The summer, late in commencing as regards temperature, may be said to have terminated with the beginning of this month. The temperature falling so early and abruptly was confidently expected to remain only tem- porarily depressed ; but such expectations have been disappcinted. Boston.—Sept. 1. Fine. 2. Cloudy: rain early a.m.: rain a.m 3.Fine. 4, Rain: rainp.m. 5. Cloudy: rain early a.m. 6. Cloudy : rain early a.M.: rain P.M. 7. Cloudy : rain p.m. 8. Fine. 9. Rain. 10. Cloudy: rain early 4.M.:rain p.m. 11,Cloudy:rainr.m. 12. Stormy. 13. Rain. 14, Cloudy’: rain early a.m.: rainp.m. 15.Cloudy. 16.Cloudy. rain early a.M.: rain P.M. 17. Cloudy. 18, Fine. 19. Cloudy: 20. Cloudy: rain p.m. 21. Fine: rain p.m. 22. Cloudy : rain p.m, 23—25. Fine. 26. Cloudy. 27. Cloudy : rain p.m. 28. Cloudy. 29. Cloudy: rain p.m. 30. 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LXXVI. Facts relating to Optical Science. No. IV. By H. F. Tarsot, Esq., F.R.S.* § 1. Experiments on the Interference of Light. LTHOUGH so much has been explained in optical sci- ence by the aid of the undulatory hypothesis, yet when any well-marked phenomena occur which present unexpected peculiarities, it may be of importance to describe them, for the sake of comparison with the theory. Such appears to me to be the case with those which I am about to mention, in which, by means of a_ remarkable compensation of some kind or other, common solar light ap- pears to play the part of homogeneous light, and to achroma- tize itself, if J may use such an expression, in a very high de- gree of perfection. Sir William Herschel was, I believe, the first who took notice of the very beautiful coloured bands which are seen by looking through two prisms placed in contact. Thus, let ABC, ADC be two equal right-angled glass prisms in con- tact. We will suppose the sides A B, BC to be equal, and the thickness of the prisms to be equal to A B, in which case the combination of the two will form a cube. Let the two prisms be gently pressed together by their face A C, which must be previously well cleaned from any adhering dust, and * Communicated by the Author. Third Series. Vol. 9. No. 56. Dec. 1836. 3B 402 Mr. Talbot’s Facts relating to Optical Science. let them be fixed firmly in this position. Then ifthe observer looks through the cube at a bright , white object, or at the sky, he will see a number of coloured parallel bands, the diréction of vision be- ing supposed to be perpendicu- larly through two opposite sides, as AB, CD. If instead of this he looks through AB at a light coming from the direction X X pF MB © and then reflected internally on the face AC, he will again see numerous coloured bands upon AC, but these will’ be comple- mentary in their tints to the former ones. These coloured bands are analogous in their nature to Newton’s rings, differing only in being formed between two plane surfaces either parallel or very nearly so, and viewed by the observer at an incidence of 45°. But the beauty of the appearances may be surprisingly in- creased by transporting the apparatus into a dark chamber, and suffering a single pencil of the brightest solar light to pass through the prism, or to be reflected from the face AC. If then a sheet of white paper be held up, at any distance from the prism, the coloured bands are depicted upon it with the greatest vivacity and distinctness. ‘The transmitted bands have altogether a different character from the reflected ones, so that it is impossible to mistake one for the other, even with- out reference to the path of the ray. This experiment, easily tried, is one of the most beautiful in optical science; I shall not, however, dwell upon it, be- cause I believe it is sufficiently well known, and that it has been exhibited in some public lectures. Now, in making this experiment with care, I have observed some remarkable circumstances. The coloured bands are not, as has been supposed, isochro- matic lines. The deviation is sometimes very marked, so that a hand in the course of its progress acquires very different tints from those which it possessed originally. This fact may be considered of some importance with respect to the theory. It takes place when the prisms are in close contact, and the bands few in number. But the following is still more desery- ing of attention. When the contact of the prisms is diminished by interposing a hair between them, (still pressing them to- gether,) the coloured bands depicted upon the paper, become more numerous, narrow and crowded. Frequently they alter- A Mr. Talbot’s Facts relating to Optical Science. 403 nate a great number of times with two complementary colours. This appeared to me so remarkable that I repeated the ex- periment with additional care. The radiant point of solar light was made smaller, by transmitting the ray through a lens of short focus, and the position of the combined prisms was slowly altered by turning them round on their centre. The appearance of the bands on the paper was all the time carefully noted. I soon found a position of the prisms in which the remarkable phenomenon occurred of a complete compen- sation of colour: that is to say, that the bands were black and white. At the same time they were become exceedingly nar- row and numerous. A friend, who had the kindness to count the lines, found one hundred and ten of them in the space of two inches. On another occasion they were evidently much closer, so that we estimated their number at éwo hundred in the same space of two inches. The aid of a lens was requisite to see them distinctly. They resembled more than anything else the closely-ruled parallel lines by which shadows are pro- duced in some kinds of engraving, and which are often em- ployed in maps to represent the sea. Now, it requires in ordinary circumstances the employ- ment of very homogeneous light, in order to produce bands anything like these in number and distinctness. In the pre- sent instance, on the contrary, common solar light was em- ployed. The result therefore is quite unexpected, and it will be interesting to learn in what manner it is explained by theory. These bands are best seen in the light reflected from the face AC. And since the reflected ray does not enter the prism A DC at all, it cannot matter, I think, of what kind of glass it is composed. With respect to the other prism, it appeared to me that the experiment succeeded equally well whether it were of crown or of flint glass. § 2. Experiments on Diffraction. In the origina] experiments of Grimaldi and Newton the diffracted images of objects were merely received on screens of white paper, by which method a great part of their brightness was necessarily lost. Fraunhofer first introduced the use of the telescope in these observations; and Fresnel, I believe, that of the lens or microscope. Both these were very great improvements, though of an opposite character, and have caused the discovery of numerous most curious phenomena. In order to see these appearances in their perfection, it is requisite to have a dark chamber and a radiant point of in- tense solar light, which, for the sake of convenience, should 8B2 40+ Mr. Talbot's Facts relating to Optical Science. be reflected horizontally by a mirror. I will relate a few, out: of several experiments which were made in this manner. 1. About ten or twenty feet from the radiant point, I placed in the path of the ray an equidistant grating* made by Fraun- hofer, with its lines vertical. I then viewed the light which had passed through this grating with a lens of considerable magnifying power. The appearance was very curious, being a regular alternation of numerous lines or bands of red and green colour, having their direction parallel to the lines of the grating. On removing the lens a little further from the grating, the bands gradually changed their colours, and be- came alternately blue and yellow. When the lens was a little more removed, the bands again became red and green. And this change continued to take place for an indefinite number of times, as the distance between the lens and grating increased. In all cases the bands exhibited two complementary colours. It was very curious to observe that though the grating was greatly out of the focus of the lens, yet the appearance of the bands was perfectly distinct and well defined. This however only happens when the radiant point has a very small apparent diameter, in which case the distance of the lens may be increased even to one or two feet from the grating without much impairing the beauty and distinctness of the coloured bands. So that if the source of light were a mere mathematical point it appears possible that this distance might be increased without limit; or that the disturbance in the lu- minous undulations caused by the interposition of the grat- ing, continues indefinitely, and has no tendency to subside of itself. g, Another grating was then placed at right angles to the first, and the light transmitted through both was examined by the lens. The appearance now resembled a tissue woven with red and green threads. It seemed exactly as if each colour disappeared alternately behind the other. An alteration in the distance of the lens, altered the tints of the two comple- mentary colours. 3. A plate of copper pierced with small circular holes of equal diameter and in regular rows, was substituted for the gratings. When this plate was held perpendicular to the ray, it produced a beautiful pattern consisting of rows of circles divided by coloured lines or bars. When the lens was ap- proached to the plate, there was a particular distance between them at which there appeared in the centre of each circle a * A plate of glass covered with gold-leaf, on which several hundred parallel lines are cut, in order to transmit the light at equal intervals. Mr. Talbot’s Facts relating to Optical Science. 405 black spot, as small and well defined in appearance as a full point in a printed book, being a curious instance of the well- known fact, of the interference of rays of light producing darkness. This black spot was seen in all the circles at once, in consequence of their having equal diameters. 4, When the copper-plate was placed obliquely and held in various positions, a great variety of very singular patterns were displayed, which can be compared to nothing so well as to tissues woven with threads of various colours. It would be impossible to describe these, any more than the ever-changing figures of the kaleidoscope. ‘They seem to vary ad infinitum, and in whatever position the plate is placed, they appear al- ways as distinct as if they were in the focus of the lens. 5. In most optical experiments it is essential that vision should be performed along the axis of the lenses which are employed, or very nearly so. But in these experiments this singularity occurs, that the lens may be placed in any posi- tion; so that when held even very obliquely the only effect is a considerable alteration in the pattern, which in other respects remains as distinct to the eye as before. The experiments hitherto related, are some which I had the pleasure of show- ing to some distinguished members of the British Association a short time previously to the late meeting at Bristol; and are communicated in the hope that they may prove interesting to the cultivators of optical science. § 3. Remarkable Property of the Iodide of Lead. This substance possesses a property of a singular nature, which I believe differs from anything previously described ; or if it is reducible to known laws of chemical and molecular action, offers at least a very striking and beautiful example of them. If a solution of acetate of lead is mixed with a saturated solution of hydriodate of potash, and the’ mixture well stirred, the iodide of lead which is formed in abundance, though at first yellow, speedily grows pale, and afterwards becomes perfectly white. If a small quantity of this is taken when freshly made and moist, and squeezed between two plates of glass, it may be seen by the help of a microscope to be en- tirely composed of very delicate capillary crystals; and if in this state it be laid aside, I do not find that it undergoes any change after being kept several months. But if, while fresh, it be warmed over a spirit-lamp, it sud- denly turns yellow, the first impression of the heat being suf- ficient to produce that effect. As soon as this happens, it should be removed from the lamp and again examined with 406 Mr. Talbot’s Facts relating to Oplical Science. the microscope, and it will be seen, not only that the colour is changed, but that all trace of the white capillary crystals has vanished, and instead of them the field of view of the microscope is covered with an assemblage of transparent yel- low crystals which are in shape thin flat regular hevagons. But after a few minutes, as the plates of glass grow cool, the white colour returns as before, and the microscope now shows again a multitude of white capillary crystals, the hexa- gonal ones having in their turn entirely disappeared. The singularity of this change, which may be repeated several times,—the remarkable fact of being able to view the same substance, alternately of two different colours, and with different forms belonging to those colours, induced me to endeavour to see in what manner such a singular meta- morphosis took place. I therefore took the plates of glass when cold and adjusted the microscope upon one of the ca- pillary crystals contained in them. It looked, when much magnified, like a cylindrical thread of glass, of a clear white colour and transparent. I then, without deranging the ad- justment, placed a small spirit-lamp beneath the glass, at a moderate distance, and watched the effects of the heat. Af- ter a short time I observed the cylindrical thread shrink in diameter, and at the same moment the axis of the cylinder split open, and a yellow. crystalline plate protruded itself through the opening, increasing in size every moment, while the re- mainder of the white crystal quickly dissolved and disappeared. This happened at several points of the axis of the cylinder, so that when the change was complete, the yellow hexagons were not unfrequently found arranged in a row or straight line indicating the position of the former crystal. When the heat is more suddenly applied, the dissolution of the white crystal is proportionably more rapid, and the yellow hexagons start into existence before the observer’s eye with a sudden- ness which is very surprising, and increase so rapidly as to triple or quadruple their diameter in a second of time, pre- serving all the time the exact figure of the regular hexagon. Most of them are of a full yellow tint, but some are of a greenish yellow, and some of a peculiar light brown, which variety of tint appears a circumstance worthy of remark, but I do not know upon what cause it can depend. There is something in this experiment which is very pe- culiar. We are accustomed to see salts dissolved or melted by heat; or if they are of an insoluble nature, at any rate they remain inert and passive when heated. But here we have a salt which crystallizes when heated, and the more rapidly the greater the heat. I have described the On the Carboniferous Series of the United Statcs. 407 manner of change of this substance from its white to its yellow crystalline form. And the following is nearly what happened during its return to its former state. When it cools, the white crystals begin to shoot, and if the microscope is adjusted upon one of the yellow hexagons, it is seen to remain quiet and undisturbed until one of the white needles, which elongate rapidly, passes near it. But when the needle passes it, even at what appears in the micro- scope a considerable distance, the hexagon becomes corroded on its edges, and then breaks up irregularly, and quickly dis- solves. I observed that when a needle, during its growth, happened to strike a hexagon, this seemed to check it for an instant, and then it subdivided itself into a number of ramifications or smaller needles which diverged from that point; es if the force (probably of an electrical nature) which caused the growth or formation of the needle-crystal had been deranged or subverted by the disturbing influences which it had met with. The change from the white to the yellow form may be re- peated four or five times; but when too much water has been evaporated by the heat, it ceases to occur. The white cry- stals then merely dissolve when heated, without the formation of the yellow ones. Remarks.— Are the white and yellow crystals identically the same substance, assuming different forms at different degrees of temperature? Is this a case of what has been termed di- morphism? If I may venture a conjecture, 1 should say that the yellow crystals are a definite compound of the white cry- stals with water. But however this may be, it appears to me that this and other properties of the iodide of lead are worthy of being more particularly examined.* LXXVII. On the Carboniferous Series of the United States of North America. By Ricuarv Cow.ine Taytor, Esg., F.G.S., &¢.+ HIAD just completed two articles on the upper series of transition rocks, and the relative positions of the deposi- tories of bituminous and anthracitous coals in Pennsylvania, with various detailed illustrative sections, which 1 had pro- * These two forms of iodide of lead are noticed in Dr. Inglis’s * Ewv- tracts from his Prize Essay on Iodine ;” Lond. and Edinb. Phil. Mag., vol. viii. p- 19.—Epir. + Communicated by the Author. 408 Mr. R. C. Taylor on the Carboniferous Series posed to myself the honour of laying before the Geological Society of London, when the interesting paper of Mr. Weaver in the Lond. and Edinb. Phil. Mag. for August 1836, reached me. I do not know how far what I have therein communi- cated may influence the opinions of this experienced geologist on the subject of the age of those coal deposits which I have imperfectly defined under the denomination of transition; but for similar reasons to those which have led to Mr. Weaver’s communication in the Magazine, I am induced, through the same medium, to state how I have arrived at a different opinion to that which this gentleman entertains, on a very interesting portion of American geology. I should greatly hesitate in differing from an authority so deservedly eminent, and should be disposed to adhere with much less tenacity to the views which he has done me the honour to quote, but for the frank admission that he has, unfortunately, not had the advantage of seeing the district in question. However, I rejoice to per- ceive that the geology of this country is attracting the atten- tion of scientific observers, who have laboured so much and so usefully in Europe, and who apply the experience acquired in one quarter of the globe to the elucidation of unsettled geological phaznomena in another. Mr. Weaver inclines to the opinion, in support of which he adduces more than one authority, that the immense series of Pennsylvania rocks, amongst which are some inclosing nu- merous thick seams of anthracitous, passing into bituminous coals in certain places, belong altogether to the secondary car- boniferous series or order. It is scarcely necessary to enter into a detailed statement of all the evidence which has occa- sioned a contrary decision, and which led to the classification of the eastern coal-fields and the vast succession of conglo- merates and red shales and sandstones, with the grauwacké and the upper series of transition rocks. The arrangement I have adopted, for the present, may be very shortly recapitulated ; commencing with the highest. 1. The (almost) horizontal carboniferous series, forming the great western bituminous coal-field of this country, whose eastern outcrop is the summit and the escarp- ment of the Alleghany mountain range, through the greater portion of Pennsylvania. All geological writers, I believe, concur in denominating this a secondary coal formation. This series includes the conglomerate, or pudding-stone, and grit, resembling the millstone grit, on which the series is unquestionably based. 2. The Old Red Sandstone, and red shales, many thousand feet thick. The dip of its numerous beds, passing of the United States of North America. 409 beneath the coal formation, increases gradually in de- scending, until they are but a few degrees from ver- tical, in central Pennsylvania. Mr. Weaver is satisfied with the existence and identity of this group in York State, but not that it is identical with that which I have traced from the same State and shown to pass imme- diately beneath the bituminous (secondary) coal-field of Pennsylvania in Tioga. 3. The Upper Transition and Grawwacké Series, commen- cing at the termination of the red shales and sandstone at the base of the Alleghany mountain, and dipping at a very high angle under that mountain and the bitu- minous coal on its summit, the whole series being much broken and heaved up on its edges, inclining in several anticlinal and synclinal groups. In Pennsy]- vania this series consists of at least eight zones of (transition) limestone, in general deficient in fossils ; and as many zones of sandstones and conglomerates, stretching parallel with the Alleghany. ‘The aggre- gate of this upper transition system, even on the lowest computation, is of enormous thickness. It comprises four or five troughs or basins containing coal, which on the east side of the State is anthracitous, and on approaching the south-west, contains upwards of six- teen per cent. of bitumen and volatile matter. Mr. Weaver, and one or two other writers, conceive that the whole series, from No. | to No. 3, inclusive, is secondary. If so, then must the grauwacké and upper transition series be absent; nor can the red sandstone under the Alleghany mountain and coal-field, be the old red sandstone, as I pre- sumed. I must confess that I have not seen beneath the great Alleg- hany coal-field a formation fully answering to the characters of the carboniferous limestone. No such rock interposes be- tween this secondary coal-field and the red sandstone, for the occasional beds of thin gritty gray limestone, resembling the “‘ cornstone” in the old red sandstone, cannot of course be its representative. If we select for this purpose one out of the eight zones of limestone, we might expect to find it in the first and most western; but although this slaty limestone con- tains some fossils in particular localities, it has no claim, par excellence, to the title of the carboniferous limestone. In York State the limestone which is thought to resemble in geological age and character the carboniferous limestone of Europe, appears decidedly lower in the series than the group I have designated as the old red sandstone, but at the same Third Series. Vol. 9. No. 56. Dec. 1836, 3C 410 On the Carboniferous Series of North America. time it (the limestone) reposes upon another red sandstone which Mr. Weaver considers the true old red sandstone in question. I have carefully traced these upper red sandstones from the State of New York until they sink under the great bituminous coal-field of Pennsylvania at Blossbury. The carboniferous limestone appears on the west side of the Alleghany mountain, accompanying the coal, in Tennessee, Illinois, Kentucky, and Indiana. Its resemblance to the mountain limestone of England is, I believe, admitted by all European as well as American geologists. I am far from be- ing certain of its presence to the eastward of the outcrop of the secondary coal-field in Pennsylvania; and I doubt if in York State this is the same formation which in the west is in close approximation with, and even contains, coal seams. I do not know which of the calcareous rocks is meant by Pro- fessor Eaton, as the ‘limestone which supports the strata containing the Pennsylvania coal.” My diagrams, which have been laboriously worked out, exhibit no limestone in Penn- sylvania, between the secondary coal series and my old red sandstone group which averages a mile thick. The descrip- tion, therefore, refers to the contorted and frequently highly- inclined limestones, which range alternately with the upheaved arenaceous rocks in front of the Alleghany mountain, along an area seventy miles broad. Mr. Weaver infers (p. 117.) that all the carboniferous limestone series of the north-east part of Pennsylvania supports equally the bituminous se- condary coal of Clearfield, Lycoming, Tioga and Bradford, and the anthracitous deposits of Wyoming, Lehigh and Schuylkill; the red sandstone and shales being in this view continuous or identical. Here, therefore, is the point of difference with the views I have been led to entertain. I see that both in the acknow- ledged secondary bituminous coal region, and in those of the anthracite districts, the carbonaceous deposits are alike based on red sandstones and red shales; but the sections distinctly show, that these are neither similar nor continuous beds, either of coal or sandstones; but are of different dates, the lat- ter being referrible to the transition series, the former to the secondary. On the north-east extremity of the secondary coal-field, the subjacent rocks, being much more horizontally disposed than further to the south, are more obscurely developed; but all along the eastern escarpments of the Alleghany the relative position of the entire series seems apparent enough, when traced out with ordinary caution. Mr. Weaver, however, maintains that the application of the term old red sandstone, to that rock immed ing on carbor J hav series in the formal On the in sirous views pared depos order Eato1 A befor good geolt New Phi Mr. I’. O. Ward on the Motion of the Arm. 411 immediately beneath the great coal-field, is incorrect, it be- ing only “ an alternating series lying above the great body of carboniferous limestone.” This objection is obvious, if what I have termed the transition limestone at the base of this series be secondary, “ carboniferous;” and if it can be proved, in the district I have imperfectly described, to ‘* repose con- formably on the extensive formation of old red sandstone.” On this head I wish to be understood, not as insisting on the infallibility of my own individual sentiments, but as de- sirous of apprising geologists of the grounds on which those views were founded. At the same time I am not quite pre- pared to admit, with Mr. Weaver, that the whole of the coal deposits in Pennsylvania, belong to one great carboniferous order, and that the fact “is fully established by Professor Eaton.” (p. 131.) A vast deal of investigation remains yet to be entered into before these debateable points can be adjusted. There is good prospect of some of them being shortly elucidated by the — geological surveys simultaneously going on in the States of New-York, Pennsylvania, Maryland and Virginia. Philadelphia, Sept. 23, 1836. LXXVIIL. Physiological Remarks on certain Muscles of the Upper Extremity, especially on the Pectoralis Major. By F.O. Wann, Esq., King’s College, London.* [With a Plate.] HERE is a remarkable fold in the tendon of the pectoralis major, which, though described by all anatomists, has never yet, I believe, been explained. ‘The muscle consists of two portions, one smaller and upper, arising from the clavicle, and passing downward and outward; the other larger and lower, arising from the sternum and ribs, and having a ge- neral direction upward and outward. The fibres of the muscle thus converging towards each other, terminate in a flat tendon several inches wide, which is attached to the upper part of the humerus. Instead, however, of having the usual simple insertion re- presented in Plate IV. fig. 1, the lower part of this tendon is folded up, behind the upper portion, so that the margin B appears above the margin A, as represented in fig. 2. As it is an axiom in physiology that every arrangement is to be accounted for, this peculiar twist has given rise to se- veral speculations. Some suppose it designed merely to di- minish the extent of the insertion. Others believe it to have * Read before the Royal Society June] 6th, 1836: and now communicated by the Author. 3C2 412 Mr. F. O. Ward’s Physiological Remarks the effect of equalizing the length of the muscular fibres. But independently of the consideration that the insertion would have been quite as compact if the tendon had been thick and single, instead of thin and double; and that the fibres are not by any means equal in length, according to the second hy- pothesis,—both explanations are defective, in as much as they show no reason for the muscular fibres crossing each other, so that the upper are attached below, and the lower above, the medium point of the whole insertion. I think that the arrangement becomes perfectly intelligible when the separate actions of the upper and lower portions of the muscle are considered with reference to the species of mo- tion those actions require. The separate action of the lower fibres is to depress the arm when raised; that of the upper fibres, to raise the arm when depressed. Of this any person may convince himself by laying the hand on the muscle; first, while imitating the action of hammering; and then, while raising or supporting a weight: in the former case he will perceive a momentary convulsive contraction of the lower fibres; and, in the latter, a steady, continued tension of the upper. In the third and fourth sketches which exhibit these posi- tions, the several directions of the humerus, and of the upper and lower portions of the muscle, are represented by lines, the arrow-head denoting in each figure which set is exerted, and in what direction it acts. Now since the humerus is a lever having the fulcrum at one end and the resistance at the other, the velocity it ac- quires must be directly, and the force inversely, proportionate to the proximity of the moving power to the fulcrum. The most common, and therefore most important purpose, to which the depressing fibres are applied, is that of bringing down the arm in using the hammer, pickaxe, &c., as the car- penter, blacksmith, goldbeater, and a hundred other artizans testify. In these motions velocity alone is required from the muscle, the gravity of the tool giving force to the blow; and to produce this velocity the lower division is attached near to the fulcrum. Again, the commonest employment of the upper fibres consists in such actions as lifting, drawing, and the like, in which force, not velocity, is the desideratum; and, in order to obtain force at the expense of velocity, the insertion of these fibres is brought down as far as possible towards the re- sistance. It is remarkable that, in each instance, that very fasciculus of the muscle, which possesses most of the action peculiar to its division, possesses likewise that very point of the insertion on the-Motion of the Arm. 413 which affords it most of the leverage it requires. ‘Thus it is not the uppermost portion, a, of the elevating division, (see the Italic letters in figs. 2 and 4,) which is attached to the lowest point, D, of the insertion, because there are succeed- ing fibres (as 8, figs. 2 and 4,) which form a less acute angle with the humerus while depressed: whereas it is the lowermost fasciculus (C, fig. 2,) of the lower division, that seeks the highest point, B, of the insertion, because this portion forms the least acute angle with the humerus when elevated (see fig. 3). ‘This trait adds another to the innumerable proofs of the minute accuracy of the animal organization. Any action which requires from either portion, a species of motion contrary to that which it is adapted to produce,—as raising the body by the hands, which requires force from the fibres of velocity,—soon fatigues the muscle. Turning a winch, which is another instance of the same kind, is notoriously a very disadvantageous application of human strength; and any employment in which steady and forcible pushing has to be performed by the arms raised above the head, is extremely fatiguing. In throwing a heavy quoit, which requires both accuracy and force, the arm is swung by the side; but in throwing a light ball, for which velocity is requisite, the arm is always swung above the head. Cricketers are practically such good physiologists in this respect, that they have enacted a law which compels the bowler to swing his arm by his side in throwing the ball, —because, if the ball were flung “ over- handed” at the wicket, from so near a point as the bowler’s station, its velocity would be unmanageable; whereas the ** long-throw” who has to send up the ball from a distance, always swings his arm above his head. The muscles associated with each division of the pectoralis major bear out the proposed explanation by the analogy of their insertions. ‘Thus the coraco-brachialis, and the anterior fibres of the deltoid, which cooperate with the upper division of the pectoralis major, are attached to the front of the hu- merus, half-way down; evidently for the purpose of gaining force, which they do want, at the sacrifice of velocity, which they do not. On the contrary, the teres major and latissimus dorsi, which assist the lower division of the pectoralis major in depressing the humerus, act, like that muscle, near the fulcrum of the lever; being attached to the inner margin of the bicipital groove, just opposite to the pectoralis tendon. These two muscles, indeed, are in several respects analogous to the two divisions of the pectoralis major. ‘The teres major, which is superior and smaller, and arises from the scapula, may be 414 Mr. I’. O. Ward’s Physiological Remarks compared to that portion of thepectoral which is superior and smaller, and arises from the clavicle; and the latissimus dorsi which is inferior and larger and arises from the vertebre and ribs, resembles that portion of the pectoralis major which is inferior and larger, and arises from the sternum and ribs. The tendons of the two dorsal, like those of the two pectoral muscles, are continuous at their lower margins, and, as if to render the analogy complete, (though, in fact, to render the leverage suitable,) the lowest fibres of the latissimus dorsi are folded around the teres major, and inserted above it into the humerus; because they are most nearly at right angles with the bone when lifted to strike, and therefore most effective in drawing it down. Fig. 5 is a front view of the insertion of these two muscles, B representing the teres major, C the latissimus dorsi folding round it to gain a higher point of at- tachment, A the tendon of the pectoralis major raised out of its natural position, and D the bicipital groove to the borders of which these muscles are attached. ‘The proposed explanation is further borne out by the comparative anatomy of the pectoral muscle in birds, in which it is developed to a very large size on account of being the principal motor of the wing. In these animals there is no crossing of the fibres of the pectoralis ; they all assist in performing one action, and are consequently inserted in regular order, those which are superior at their origin having also a superior insertion, and vice versa, as may be seen in fig. 6, which is a sketch of the pectoral muscle of a pigeon. ‘The turning under of the fibres represented at a seems at first sight to indicate a decussation of the upper and lower portions of this muscle, similar to that which -occurs in the corresponding organ of man. But the resemblance disappears when the muscle is divided along the dotted line dc, and the humeral portion reflected as in fig. 7. It then becomes evident that the lower fasciculi though form- ing a little bundle partly distinguishable from the rest of the muscle, and inserted by a separate slip of tendon, nevertheless join the bone Jelow the upper fasciculi, and below the central point of the whole insertion. Professor Rymer Jones, who very kindly examined with me the muscles of the breast in the pigeon, confirms the accuracy of this observation. There is, however, an action, which, as it furnishes man with his most obvious means of self-protection, must have been carefully provided for by Nature, and which seems to throw doubt on the correctness of the foregoing explanation. I mean the action of throwing the extremity forward, as in boxing. In this action, which requires great velocity, although all the fibres of the pectoralis major are in some measure on the Motion of the Arm. 415 brought into play, the upper set, that namely of least velocity, are, it must be admitted, the principal agents, so far as this muscle is concerned: in other words, Nature, according to my explanation, causes a muscle to work at disadvantage, in an action of essential importance. This, I think, is only an apparent difficulty, for in this mo- tion as correct a balancing of leverage is displayed, as can anywhere be found throughout the body. The fist is thrown forward by a double motion. The humerus, represented by AB, fig. 8, revolves round the point A till it takes the position A C, while the forearm, represented by B D, revolves round the point B till it takes the position B E, so that the resulting position of the whole extremity is A Cf. ‘The upper division of the pectoralis major, the anterior fibres of the deltoid, and the coraco-bra- chialis, are the main causes of the first motion; the triceps, anconzeus, and supinator muscles, of the second. The distance which the forearm passes through, repre- sented by the curve 2, exceeds considerably the space tra- versed by the upper arm, represented by the curve 1; but as the motion of the forearm round the point B is from above downwards, its extensors have no weight to raise; on the contrary, are assisted by gravity. Whereas the humerus, though it moves through a shorter distance, moves upward, and carries with it the forearm, so that its elevators have to raise a considerable weight. In order that these two motions may be completed in the same time, the former requires the greater velocity, the latter the greater force. Accordingly the triceps and its associate extensors, act on the ulna by a lever between one and two inches long, while the three elevators of the humerus act by levers whose respective lengths are about four, five, and six inches. See figs. § and 9, in which P represents the tendon of the pectoralis major, D that of the deltoid, C that of the coraco-brachialis, and T that of the triceps. I may just add, (for it is interesting to observe the uncon- scious acquaintance which every man has gradually acquired with the precise capabilities and most effective application of every fibre in that complicated machine, his own frame,) that in preparing to strike a blow the elbow never hangs close to the side, as in fig. 11, butis always thrown out, as in fig. 12; in order that the elevator muscles, all of which draw more or less inward, as well as upward and forward, may act during the strong effort at their full advantage. Thus, then, not only is the leverage of the upper and lower portions of the pectoralis major accurately adapted to the ac- 416 Mr. F. O.Ward’s Physiological Remarks tions of lifting and hammering which they respectively per- form, but it is so proportioned to the leverage of the triceps, that the two muscles cooperate harmoniously in the action of striking a blow forward; unequal spaces being traversed and unequal resistances overcome, in the same period of time, so that the resulting position of the limb is precisely the one re- quired: while the strength of the one set of muscles bears such proportion to that of the set with which it acts in concert, that both remain unfatigued for the same number of ac- tions. Itis this diversified adaptation of parts, which forms the chief characteristic of the mechanism of Nature. Working with unlimited means, she yet works with scrupulous ceconomy ; in her structures no power is redundant, nor a single advantage lost; so that, however completely an arrangement may sub- serve one primary purpose, we find, upon renewed examina-. tion, an equally accurate adjustment to several secondary ends. When the means of estimating with precision the contractile force of the muscular fibre, are obtained, I have no doubt that these compound relations of power, lever, and motion pro- duced, will form an interesting study*. Magendie + observes, that the intensity of muscular contrac- tion depends partly upon certain peculiarities in the organiza- tion of the fibres, such as size, firmness, colour, &c., and partly upon the energy of the cerebral influence, or the “ puissance de volonté,” by which they are excited to action. Muscles ac- quire far more than their ordinary power, during those affec- tions of the mind which stimulate the brain to strong action, such as rage, madness, &c., and also during certain convulsive * Borelliin his posthumous work De Motu Animalium, published in 1680, has entered into an elaborate analysis of the mechanical relations cf the body, with a view to determining the absclute force of the muscles. But unfortunately his experimental data (see, for instance, Pars prima, cap. 8,) are as loose and unsatisfactory as the subsequent calculations are minutely accurate; and his reasonings are interwoven with a purely specu- lative hypothesis of the nature of muscular fibre, which he supposes to consist of minute rhcmboidal vesicles, contractile by inflation. By these means he brings out very startling results. Thus to the flexor longus pollicis manus alone, he attributes a tractile force of 3720 pounds ; to the deltoid of 61,609 pounds; to the intercostals of 32,040 pounds; to the gluteei of 375,420 pounds, &c. (see cap. 17, prop. cxxiv. et seg.) Dr. Bos- tock considers his estimate of the force of the muscles of the thumb to be a hundred times too great. He has not noticed the twisted tendon of the pectoral in man, nor calculated its force and leverage. The only remarks upon its strength I can discover, are in cap. 22, prop. cciv., where, from its small relative size, he proves it to be impossible ‘‘ ut homines propriis viri- bus artificiosé volare possint.” + Physiologie, vol. i. p. 275. on the Motion of the Arm. 417 diseases which have similar cerebral effects. From these and some other facts adduced, he infers that cerebral influence on the one hand, and certain qualities of the muscular. tissue itself on the other, are the two elements of muscular contractility. Mayo has indicated a method of determining the maximum strength of individual muscles, by ascertaining the weight that is required to rupture their tendons. This mode is founded upon the argument that the tension which the tendon can sustain, probably exceeds but little that which the fibres can exert; a supposition which is analogically probable, and in some measure supported by facts, since in praeternatural con- traction sometimes the tendon, sometimes the trunk, of a muscle gives way*; proving that there is no great difference between the active and passive strength of these organs. The constant and equable stream of galvanism, afforded by Daniell’s new battery, will furnish, I think, a good means of comparing the strength of muscles, of regular shape and equal size, by ascertaining the contractile force it induces in its pass- age through each. In order to subject any muscle to this experiment, it should be separated from its fellows, and, at the distal end, from its insertion. By the tendon, thus detached, it should be con- nected with a spring moving an index; and the bone, into which its opposite extremity is inserted, should be firmly fixed at a known distance from the spring. The trunk of the muscle should then be made part of the circuit; and the distance to which it moved the index during the transmission of the cur- rent for a given period (say one minute) might be taken to express the force of the muscle as compared with others sub- mitted to the same treatment}. The comparative dimensions and weight of such muscles as resemble each other in colour, firmness, and texture, would also probably bear some proportion to their comparative force. Although neither of these methods of estimating muscular contractility could be depended on alone, yet by a judicious application of each in turn, to corroborate or correct the re- sults furnished by the others, a close approximation might at last be obtained. And since we have proof that there is an accurate balancing of muscular force in the fact that muscles, or sets of muscles working together, are fatigued, equaliy and simultaneously, we may fairly expect that whatever the ab- * See Tetanus Cooper’s First Lines of Surgery. + The contraction of the muscle only occurs at the instants of com- pleting and interrupting the circuit. Contact must therefore be broken and renewed at regular intervals during the experiment; which is readily effected by means of a pendulum connected with the wire. See Bec- querel’s T'raité de V Electricité, vol, iv. p. 306. Third Serics. Vol. 9. No. 56. Dec. 1836. 3D 418 Mr. F.O. Ward’s Physiological Remarks solute strength of muscles in different individuals may be, their relative strength will be found nearly alike in all, ex- ception being of course made for the influence of habitual employments upon particular muscles. If, for example, in one arm the power of the biceps were one, and that of the tri- ceps two, in another arm the power of whose triceps was two, that of the triceps would be four, or thereabouts ; or if not so, the difference would be compensated by a counter-variation in the leverage. It is also probable that in the same individual, under va- rious conditions of lassitude or excitement, whether produced by bodily or by mental affections, each muscle retains its normal relation in point of strength to the others, whatever may be its actual gain or loss of contractility. So that if this ratio were once established by the mean results of cautious experi- ments, it would be possible, from the absolute strength of one muscle, or set of muscles, to deduce by calculation the absolute strength of each of the remaining muscles in the same individual. We should of course meet with irregularities; some caused by disproportionate growth, and bearing an ascertainable re- Jation to its degree; and others depending on circumstances beyond the range either of observation, or of calculation; but if a standard proportion does really exist, the deviations from it are certainly in opposite directions, and the true ratio will be discovered by taking the average of an extensive series of measurements and estimates. And when we reflect that within the last few years constant numerical proportions have been developed by Wenzel, Berzelius, Dalton, and others, in the chemical affinities of ponderable matter, and by Faraday in the action of the imponderable forces; and—still more to the purpose—that mathematical laws so fixed and definite as to serve for the distinction of species, have been discovered by Schimper and Braun* to regulate vegetable growth ; it seems: not unreasonable to surmise, that numerical proportions, as certain and invariable, may govern the secret workings of animal life, and be hereafter revealed by the discovery of ac-: curate, though involved, mathematical relations, between the several organs of the animal machine t+. A rigorous analysis of the mechanical relations of the mus- * Archives de Botanique, vol.i.; Martin’s Abstract of Braun’s Paper ; Henslow’s Introduction to Botany, p. 124; Lindley’s Introduction to Botany, second edition, p. 91. Lindley thus states the result of the inquiry : “‘ The whole of the appendages of the axis of plants, — leaves, calyx, corolla, stamens, and carpels,—form an uninterrupted spire governed by laws which are nearly constant.” For the causes’ of the occasional deviations fram these primary laws, see Henslow’s Introduction, § 121. + I trust that an hypothesis thus indicated by the analogy of several as- certained laws, capable of inductive examination, and whether erroneous on the. Motion of the Arm. 419 cular and osseous systems in various animals, would form a good foundation from whence, in future, to push forward such inquiries; and, besides this remote and dubious utility, con- tingent on the soundness of the foregoing speculation, such researches would be of considerable immediate advantage to science. They would give the geologist a new point of view in which to examine fossil bones, and might enable him to deduce, from the relative size, shape, and situation of the marks indicating muscular insertion, new particulars concern- ing the strength and speed of extinct creatures; they would probably point out to the comparative anatomist analogies and differences in the structure of animals, where none have hitherto been suspected; and above all, they would tend to introduce into physiology an exactness and certainty which the science has not yet attained. As a first step to such an analysis, I intend shortly to attempt a set of experiments on the contractility of the muscular fibre, by the several methods that have just been described. ‘Those who undertake such researches should bear in mind that the friction of the tendons is an important element of the calculation. Muscles which are extended in a straight line between their attachments, and undergo no friction but that of the investing cellular tissue {as the gastrocnemius), have greatly the advantage of those whose tendons play over trochlear surfaces (as the obturator or not, likely to suggest to its investigators some useful experiments, will not be classed with the extravagant iatro-mathematical speculations which retarded the progress of physiology in the seventeenth and beginning of the eighteenth century. ‘“ Prudens questio dimidium scientiz,”’ says Lord Bacon, a sentiment admirably elucidated by Herschel in the Preliminary ‘Discourse. ‘“ A well-imagined hypothesis,” he says, “ if it have been suggested by a fair inductive consideration of general laws, can hardly fail at least of enabling us to generalize a step further, and group together se- veral such laws under a more universal expression,...... and we may thus be led to the trial of many curious experiments, and to the imagining of many useful and important contrivances which we should never otherwise have thought of.” To which may be added the following judicious remarks of Mr, R. Young: * As in practice nothing is perfect, and few things wholly without merit, so, in theories, perhaps, none are without error, nor any’ devoid of truth. The difference between opinions seems to lie chiefly in the different proportions of truth and error which they contain. If this be true, every advance in principles is only substituting a less imperfect theory for one more so, and the last ever leaves something for futurity to correct.”—(Essay on the Powers and Mechanism of Nature, p. ix.) (We may refer the reader, on the Da of numerical proportions in animal organization, to our abstract of Dr. W. Adam’s paper, ‘ On the Osteological Symmetry of the Camel,” in Phil. Mag. and Annals, vol. ix. p- 364: the paper itself will be found in the Transactions of the Linnean Society, vol. xvi. p. 525 et seg. See also Lond, and Edinb, Phil. Mag., vol. iii. p. 457, vol. vi. p.57, for notices of papers by Dr. Adam on the osteological symmetry of the human skeleton.—Eprr. | 32 420 Mr. Tovey’s Researches in the internus), or run in grooves (as the long head of the biceps), or perforate other tendons (as. the deep flexor of the fingers), or turn through fibrous pulleys (as the digastric, the extensor of the toes, &c.). By comparing the effect of a known force acting on particular tendons, at first in their natural situations, and afterward detached and free, the influence of friction in each case would be readily determined. This source of error seems to have been very generally overlooked by writers on animal mechanics. : I conclude, for the present, with suggesting that to distin- guish the pectoralis major into “portio elevans ” or ‘ attol- lens,” and “ portio deprimens,” might serve to impress the rationale of its peculiar insertion and twofold action, upon the memory of the student. LXXIX. Researches in the Undulatory Theory of Light, in continuation of former Papers. By Joun Tovey, Esq. To the Editors of the Philosophical Magazine and Journal. GENTLEMEN, ' AVING deduced, (p. 500 of your last volume,) by a new method, the laws of the propagation of plane and sphe- rical waves in elastic media, I will now, with your permission, show how the formulz may be extended to the most simple cases which are known to occur in the undulatory theory of light, of waves not spherical emanating from a center of agi- tation. (1.) It will be remembered that in my paper at p. 270 of the last volume, the sums & were considered as comprised in three classes, when it appeared that those of the first class, com- posed of odd products of the differences, vanish, in conse- quence of the first supposition there made respecting the arrangement of the molecules. The sums also of the second class, composed of even products involving odd powers of the differences, were neglected; because the terms of these sums must be about half of them positive and half negative, and consequently the sums themselves very small in comparison with those of the third class, which last, being composed of even powers of the differences, have/their terms all positive. (2.) Ifthe ‘radius of the sphere of influence be not very much greater than the intervals between the molecules, the sums may or may not be sensibly the same for different direc- tions of the coordinates, according as the intervals are the same or different for the different directions. Suppose, for example,’ every eight adjacent molecules to be at the corners of a rectangular parallelopiped; suppose fig. 1 to be a sec- tion of the medium, the dots denoting the molecules in their Undulatory Theory of Light. APA places of equilibrium ; and suppose the circle to be a section of the sphere of the influence of the molecule which occupies its centre; then, the intervals between Fig. 1. the molecules being greater in the ho- -rizontal than in the vertical direction, it is manifest that the sums in general will vary according to the directions of the coordinates, and that, when the planes of the coordinates are parallel to the planes which form the paral- lelopipeds, the sums of the second class will have for every positive term an equal negative term, and consequently that these sums will vanish. If the molecules of the ather and those of a transparent body form a compound vibrating medium, and if the obser- vations just made be regarded as having reference only to the molecules of the body, the consequences will still be the same. (See paper at p. 270 of vol. viii.) (3.) Since no light can be discovered to arise from the dis- placements £ *, we will neglect them, and then the equations (3.) of the paper at p. 7 of vol. viii. become ~ q2 cae = mz 4 0(0) An+w(r)(AyAyn+Az Ad Ay} > dé de = mz { 9(r) AS+(r)(AyAn+AzAt) A “} , Putting (1.) dy Diet re 5. Ayn Shah dea Mae + &e. dé de “Ax Ag= ade At ch ares Tat Bee. and substituting these values in the previous equations, it is obvious that the principal sum of the second class (art. 1) is =. (r) Aa’ AyAz. Now yand z may be taken in any di- rections which are perpendicular to x and to one another ; and if the directions be so chosen as to make this sum vanish, we may neglect the other sums of this class, and then the sub- stitution will transform the equations into the second and third of the equations (2.) at p. 272, and the yelocities of the waves will be determined by the formule previously deduced in the paper at p. 500. (4.) Suppose then x,y, 2, to be rectangular coordinates, and the axis of x, to be fixed in the medium; suppose the plane of x and y to coincide with this axis; and suppose the mole- cules to be so arranged that the turning of the coordinates round it would not sensibly affect the felties of the sums. In * Airy’s Math. Tracts, p. 340, art. 101. 422 Mr. Tovey’s Researches in the this case the sum =. (7) AxtAyAz (art. $) will vanish: for let the plane of x and y pass through the molecule m and divide its sphere of influence into io hemispheres ; then, since the arrangement of the molecules will, by the supposi- tion, be sensibly the same in both, it follows that the terms of this sum will be half of them positive and half negative, and will destroy each other. (5.) If we denote the length of the waves ee: | by ul : sat re: n, a, A,, 4,3 and their velocities —, ae. oo > by Uv, Ds ys u Mt the equations (3.) of the paper at p. 500, give se A? te Po] Laie andre + &e. ), 2 Set ace sli i Vola eee Re eas {6.) Since our object is ee, to ascertain the forms of the wave-surfaces, we will, for the present, neglect the terms in these equations which depend upon the lengths of the waves, and suppose v, = s,, v,, = s,,; then, by the formule at p. 271, we have m oo @ = (¢ (7) Jt b(r) Ay) Aa, oh (3.) Oy; = = (¢(r) + (r) A2*) Aa. Now, let the axis of ‘z coincide with that of z,, and let 4 be the angle formed by the axes of x and z,; then, when , y, z, and x, ¥,,2,, have the same origin, and are coor- dinates of the same molecule, we have, by the principles of analytical geometry, x = x,cos§ —y,sin6, y = 2,sin$ + y, cosé, and consequently, Ax = Ax,cos$— Ay siné, -Ay= At, sing + Ay, cosé, ON SS Az, : The last equations give sae oles yee eh cos? @ +.Ay? sin? ?—~2Ax,Ay,sin§cosé, Az? =A x, F, and if we EA these values in the second of the equa- tions (3.), we have Undulatory Theory of Light. 423. ee _ {cos §=.(o(7) + (7) A 2?) Ax?+sin? 62 (8 +9 0) S29) dys! —m sin 6 cos 6=.($ (7) +(r) Az?) Az, Ay,. The third sum in this equation must be zero in consequence of the supposed arrangement of the molecules round the axis of z,, and therefore, if we denote by c? and c,? the products of the first and second sums multiplied by > we have v, = W (c? cos? 6 + c,* sin® 9). (4.) (7.) Let CD, DE, (fig. 2,) be elementary portions of a wave-surface diverging from the centre of agitation O; let A D, B E, be planes coincid- ing with CD, DE; and let Fig. 2. O A, O B, be perpendiculars to these planes. Then the velocity with which the wave is, at CD, transmitted in the direction perpendicular to CD, must be equal to the ve- locity of a plane wave moving in the direction of OA; and the velocity with which the wave is, at D E, transmitted in the direction perpendicular to D E, must be the same as that of a plane wave moving in the direction of OB. Conse- quently, if we conceive an indefinite number of plane waves, which, at the commencement of the time ¢, all pass through the centre of agitation O, the wave surface will be that touched by all these plane waves at any instant. (8.) Now let a number of planes like A D and BE, all per- pendicular to the plane of the angle x, Oy,, be so drawn that their perpendicular distances from O, the origin of the coordinates, may be proportional to the values of v, given by the equation (4.); where § is the angle which the perpendi- cular « drawn from O to any plane wave makes with the axis Ox,. Then the curve in the plane of x, Oy, touched: by all these planes will, by the property of the equation (4.), be an ellipse, the axes of which are proportional to c, and c, . (9.) The phenomena of chemistry show that molecular attractions and repulsions vary rapidly at particular distances of the molecules from each other. Suppose then the forces m f(r), of the paper at p. 7, to vary rapidly at particular values dfir) ofr. The differential coefficients inh may, in Consequence, 4.24 Mr. Tovey’s Researches in the become, for these values, so large as to make the parts of the sums = which contain them so much greater than the other parts, that the latter may be neglected. Accordingly we will assume this to be the case; and then the first of the equations (3.) becomes ‘ pia rev (r)AyAz’. This equation, being symmetrical with respect to x and y, gives for v, the same value whether 2 coincides with Ox, or with Oy, (fig. 2). We shall therefore assume that v, is sen- sibly the same for all values of @. And then if we put = z.(¢ (r) + v(r) Ay?) Aua?p= ec p we have a ay (5.) (10.) Now conceive a number of plane waves, perpendi- cular to the plane of «,Oy,, (fig. 2,) all of which, at the commencement of the time ¢, pass through the centre O; and, since v, is the same for all values of 6, conceive the velocities of these waves to be all equal; then their distances from the centre O wil] constantly be equal, and the curve, in the plane of x Oy,, touched by all of them at any instant will be a circle. (11.) If the system of coordinate planes be turned on the axis of 2, the circle and ellipse (art. 10 and 8) will describe a sphere and spheroid. And since this turning of the coor- dinates will not, by the supposition (art. 4), sensibly affect the values of the sums, and consequently not alter those of v, and v,, it follows that the agitation at the centre O will in ge- neral produce two sets of waves; of which one set will be spheroidal, and the other spherical: the vibrations in the spheroidal waves being perpendicular to the axis of «,, and the vibrations in the spherical waves perpendicular to those in the spheroidal. (12.) From the supposed arrangement of the molecules round the axis of 2, it follows (art. 6 and 9,) that c = ¢,, and consequently that when 4 is zero we have v, = v,. Hence by limiting our view to a spherical and spheroidal wave, both of which emanate from the centre of agitation at the same instant, we perceive that they will constantly coincide along the axis of z,. And when 0 is aright angle we have v, = cy which shows that the spherical wave will include, or be in- cluded by, the spheroidal wave, accordingly as c is greater or less than ¢,,. , By referring to Professor Airy’s Mathematical ‘Tracts, p- 346—350, it will be seen that the results obtained in this and the preceding article are sufficient to explain the prin- Undulatory Theory of Light. 425 cipal optical phenomena presented by what are called uniaxal crystals. The Professor, following, as I suppose, the method of M. Fresnel, has deduced results similar to these, except that, by his reasoning, the direction of vibration in the sphe- rical waves is the same as we have found it to be in the sphe- roidal, and the converse. But I apprehend that the 104th and 111th articles of his valuable tract on this subject are in- consistent with each other; and that the latter, on which the question depends, is erroneous. I perceive, from the British Association’s Report on Physical Optics, that the investigations of M. Cauchy give, for the di- rection of vibration, the same result as mine; but it appears that his investigations are not founded so immediately as mine upon the physical constitution of the medium. (13.) The deductions of the last two articles rest upon the supposition (art. 6.) that % = S$; Vy = S,3 but by the equa- tions (2.), s2 An? Hew (Us - + &e.) 5 hence these deductions require a corresponding modification. But this is easily effected; for we may suppose the variations of the sums s?, Sip a Ss sthp i aeS yy BEC depending upon the directions of the coordinates, to be in general small fractions of the sums themselves. Hence, in the last equations, we 72 49 Sad Sur . / “ =) may regard 32? | 2 88constant, and (paper at p. 270 of / “ Ks : sf vol. viii.,) equal one to the other; and thus, if we put ec / 41? = A, we have, instead of the values of v, and v,, found in articles 9 and 6, won / (1m ‘3 + &e.) * a= J (e} cos’ §+¢,? sin’ 6) ~S( — a 4 &e.). It appears by these equations that the values of v, and v,,, and the ratio of one of them to the other, depend, in some measure, upon A, A,, the lengths of the waves. This is cun- firmed by experience. See Airy’s Tracts, p. 354, (14.) It is well known that light moves through glass, in its ordinary state, with the same velocity in all directions ; Third Series. Vol. 9. No. 56. Dec. 1836. 3K 426 Mr. Tovey’s Researches in the and that the velocity is not affected by any change in the di- rection of the vibrations: consequently the sums s*, s,?, &c, must, for this medium, be the same whatever be the directions of the coordinates. But it is found, by experiment, that if glass be expanded or contracted in one direction only, it ex- hibits the same optical pheenomena as an uniaxal crystal; the optical axis lying in the direction of the expansion or contrac- tion. (Airy’s Tracts, p. 403, art. 178.) Now, it is manifest that since the sums s”, s?, &c. are originally the same for all directions of the coordinates, these sums must, in the altered state of the glass, be still such that their values will not be affected by turning the coordinates upon an axis taken in the direction of the expansion or contraction; and consequently this experiment affords a verification of our formule. (15.) Whatever be the arrangement of the molecules, we have, by the equations (3.) und the assumption of article (9.); oe FS E-¥(r) Ai Aya, to 3 DE NG) bee ae 2B provided (art. 3.) the directions of y and z are so taken that Bie WT) AN BAe 3, Let x), y/, z/ be rectangular coordinates having fixed directions, and the same origin as 2, y, 2; let the axis of a coincide with that of 2’; and let 6’ be the angle between y/ and y: then (EEO 7 Ay = Ay/ cos4/ — Az/ sin4’, &z = Aysing/ + Az/cos6/. By substituting these values and, for the sake of abridge= ment, putting =. v (7) Ag Aye =i. S.b(r)AgP Adi = o', . Fe 2, Meas) Airy Ay ret ce volts we have m : m : aS , i git cos’ 4/ + = o’ sin? 6!— mo'' sin 6/ cos 6,5 m a m ‘ : = a sin? 6/ + - o! cos? 6/+ mo" sin 4! cos 6,’, 2.Y (7) Ax? Ay Az = (¢—o') sing! cos 6/ +0” (cos? 6/—sin’ 4,’ Undulaiory Theory of Light. 42 From these equations we find d(vg) _ _ dv?) cee Ere so that when («—o") sin 6/ cos 8,’ + ¢” (cos? §,' — sin?#/) = 0, the sum =.W(r) Aa’ A yAs is zero as required, while, of the expressions for 9 and v,°?, one is a maximum and the other aminimum. The last equation is always possible; for since 4 =—me.v(r)AgAyAz: : sin 26! : ; / jaar ae ‘ 2A7__ 2p/ —_ eule 7 sin 6’ cos 0,’ = proeen and cos? 97 — sin? §,, = cos 2 6’, it gives 9 gl! tan 20’ = — ‘ C—o (16.) It has been observed (art. 1,) that the sums composed of even products involving odd powers of the differences must, in general, be very small compared with the sums com- posed of products of the same degree in which the powers of the differences are all even. Let it then be supposed that az', y',2' are rectangular coordinates of which the axes are fixed in the medina and that the arrangement of the mole- cules, with respect to these axes, is such that the sums of which the terms involve odd powers of the differences A 2‘, Ay’, Az, are either zero (art.21,) or insensibly small. Let the axis ne x, coincide with that of z'; and let 6’ be the angle between y/ and y,; then A a = | cos 6’ — Az’ sing’, Az, = Ay'siné'+ Az! cos #'; and consequently, when we omit the terms involving the odd powers of the differences A 2”, Ay', Az', we have Ag ae? = Aa ay sin! - Az” Ae” cos 8 For the reasons mentioned in article (9.) we leave out of the expression for v,? (art. 6.) the function bi (r), and then v,, = cos’ 6. TEP (rz 27> Awv?+sin?6. aes b(r) Az?Ay? _ Seles: Saee Now, when the coordinates z,, y,, 2, are turned on the common axis of z, and 2’, the sum 2. (7 ) Az? A. y, must be of the same value: whether y, coincide with 7 or 2/; we will therefore suppose it to be sensibly the same for all values of #: when, again, we change the coordinates 2,54, 2,5 fora", 4, 2; the last sum in the equation will be composed of terms involving odd powers of A a’, and will therefore, by 3E2 498 Mr. Tovey on the Undulatory Theory of Light. the supposition, be insensible; hence we shall have, by sub stituting for A a? Az? its value previously found, 0," = cos’ o. = ZB. (r) (Ax? A y?sin® + Aa? 2? cos? 0") + sin? é, FEV (Aw AY® or, v2 = cos? sin? 4c! cos? 6 cos’ 6’ +c” sin? 6; if, for the sake of abridgement, we put = =. (r) A 22 Ae? = SE. y (r) Ag? Ast =c2, FE) AyP Aa = el? (17.) Let O2! (fig. $,) be the common axis of 2! and 2,; O/, Oz, Oy, O27, Oz, O7 708, Fig. 3. the axes of 5 25 Ys 2j9 To Ys 25 Zz M2 y Oy, = #, and 2’ Or = 4. Now Ox being, by the supposition of art. 6, in the plane of z’/Oy,, we will suppose O y to be also in the same plane. Then y,O0y=2/Ow a! =, cosa’ Oy = sin§, cosy! Oy = cos @, cos§!, cosz!Oy=cosd | sin §’; and thus, by the last expres- f sion for v2, we arrive at y! Yi v? = ce cos?2/Oy + c? cos*y!Oy + cl? cos’ 2! Oy. In deducing this equation we have supposed O2', Oa, Oy, to be in the same plane; but we take for granted that the value of v’!? would not be sensibly affected by turning the coordinates upon the axis of y; because ; m VS mote (r) Aw? Az?, and this sum, being symmetri- cal with respect to x and s, retains the same value when x and = are interchanged. Hence it follows that the equation is true in general, and, consequently, that if we change the angles 2! Oy, y! Oy, x Oy, for 2! Ox, y' Ox, a! Oz, it gives ang a YoY Ys Ys a 25 ¥Y By & By gives also the value of v/’. (18.) It will be remembered that v, is the velocity of waves moving in the direction of Ow, and consisting of vibrations in the direction of Oz; and that v’ is the velocity of waves moving in the same direction, and consisting of vibrations in the direction of Oy. The directions of Oy and O 2, which determine those of the vibrations must (art. 15.) be so taken Prof. Berzelius on Meteoric Stones. 4.29 at right angles to each other and to Oa, that of the expres- sions for v7 and v,?, one shall be a maximum, the other a minimum. If the last expression for v,*, and the observations subse- quently made, be compared with the expression in art. 119, and the observations in articles 120 and 121 of Professor Airy’s Tract before quoted, it will be perceived that we have now deduced the fundamental laws of M. Fresnel’s theory of refraction for biaxal crystals. But the direction of vibration is, as we have previously found in the case of uniaxal crystals, perpendicular to that which this ingenious philosopher sup- posed. The consequences of these laws have, as it appears from the British Association’s Report on Physical Optics, been so ably traced and verified by Sir William Rowan Hamilton and others, that I deem it unnecessary to pursue this part of the theory any further. I am, Gentlemen, yours, &c., Evesham, June 28, 1836. Joun Tovey. P.S. In my last paper, vol. viii, p. 501, line 2 from the bottom, for 1 read § ; p. 502, 1. 8 from the bottom, dele comma after B; p. 505, 1. 11, for <. read _ ’ In the valuable paper from M. Cauchy in your last [June] Number, I have noticed the following errors. Vol. viii. p. 461, formula (2. ), forau+bv+cw read au,+bv,+cw,; and line 5 from bottom, for w read uv. P. 462, formula (7.), for «, in the denominator read u,. P. 463, 1.13, prefix of; and line 3 from the bottom, for 0 read a. P. 464, line 14, for u; read v; ; and 1.15, for we read We. P.465, 1.12, for 19 read 16; and |. 28, for aw read au. P. 466, 1.13, for Cread 8. P. 467, lines 1 and 3, for = », in every place, read = 0; and line 10 dele the first w. LXXX. On Meteoric Stones. By Professor BerzELius.* HE author commences this interesting memoir by consi- dering which of the conjectures respecting the formation of meteoric stones is the most probable. That which refers these bodies to eruptions of the volcanos of our earth cannot be supported, on account of the distance of the places where they have fallen from any volcano, and also from the different con- stitution of volcanic products and meteorites; neither can * From the Journal de Pharmacie for February 1836: communicated by J. D. Smith, Esq., being a translation of an extract, by M. Vallet, from a memoir in Poggendorf's Annalen der Physik und Chemie, vol. xxxiil. p. 1. 430 Prof. Berzelius on Metcorie Stones. the opinion of their formation from either the common, ot’ even the accidental constituents of the atmosphere be admitted. Anaxagoras imagined that a stone which fell in his time in /Higos Potamos came from another world. This, which is probably a correct opinion, is supported by the researches of our own age. Olbers in a paper on the fall of a meteorite which occurred at Sienna in Italy, on the 16th of July 1794*, suggested, in 1795, the possibility of these bodies being pro- jected from the moon, but it appeared to him much more likely that they came from Vesuvius. Laplace likewise adopted this opinion in 1802. That part of the moon which is turned towards us is covered with elevations, and it is found that there are many mountains which precisely resemble in their external appearance those volcanos of our earth which have craters; these mountains are of such magnitude that the in- terior of their craters may be seen with good telescopes; and it can be readily perceived that one half of the interior is il- luminated by the sun, and the other is in the shade, whilst the circular opening of the crater is extremely distinct. It may then be supposed that these mountains owe their form to the same cause as terrestrial volcanos, viz. to eruptions; but if the force which produces ]unar eruptions is as considerable as the projectile force of our volcanos, the bodies thrown out ought to be projected much further from the moon than the earth; for, Ist, the mass of the moon is to that of the earth only as 1°45 to 100, and its weight is in the same ratio; 2ndly, the moon has no atmosphere, or at most one so highly rarefied that when the fixed stars are eclipsed by the moon, no refraction of the rays of light can be perceived : con- sequently the projection occurs zm vacuo, and without that mechanical resistance to projected bodies which is caused by the atmosphere of the earth, in which they soon become qui- escent; 3rdly, if a body is projected towards the earth from the moon the attraction of the earth for it continually increases, whilst that of the moon diminishes more and more; 4thly, the limit of equilibrium between the earth and the moon is much nearer the Jatter than the former. Many circumstances connected with the composition of me- teoric stones agree with what we know respecting the moom Some of these bodies contain metallic iron, which when ex- posed to air and moisture is by degrees converted into hydrated peroxide of iron, and this is the case with the minerals of the crust of our globe under such circumstances ; therefore in their primitive situation they are without atmo- # [The fall at Sienna in 1794 was of a number of meteoric stones.— EW. B.] Prof. Berzelius on Meteoric Stones. 431 spheric air, or even possibly without either air or mois- ture. Astronomical researches have not as yet discovered in the moon any traces of water large enough to be distinguished by good glasses, and M. Berzelius considers that water has not been met with chemically combined in meteoric stones. We shall see hereafter that the greater number of meteoric stones resemble each other so much in their composition that they may be considered to come from the same mountain, that is, from the central culminating point of that side cf the moon which is always turned towards the earth. A small number only present a different appearance, and it is therefore pro- bable that these proceed from mountains situated on other parts of the moon. Nevertheless meteoric stones may have their origin in an- other planet. Olbers considers that the asteroids between Mars and Jupiter may be fragments arising from the destruction of a larger planet, an idea which has induced the search for more of these fragments, and the discovery of one of them by Olbers himself. If such a catastrophe has occurred, which seems established by the great angle that the course of Pallas makes with that of the other planets, an immense number of small fragments wou!d be projected in such directions that their course around the sun being diminished, they would then during their revolution come within the sphere of attraction of other planets, and fall on them. From these preliminary considerations on the origin of meteoric stones, M. Berzelius proceeds to the chemical examination of many of them. Unable in this place to notice the processes which he em- ployed in his analyses, we confine ourselves to the results at which he has arrived, and the conclusions which he has drawn from them. I. The Meteorite of Blansko.—This stone, which induced M. Berzelius to undertake this work, fell at a quarter past six on the evening of the 25th of November 1833, in the neigh- bourhood of Blansko in Moravia. As usual it produced a very brilliant light, and its flight was preceded by noise re- sembling thunder. M. Reichenbach, who witnessed the pha- nomenon, could only collect a few fragments ; the principal mass has not yet been discovered, the surrounding country being thickly wooded*. It resembles those meteoric stones which are most com- monly met with, and may therefore be ranked with those of Benares, L’ Aigle, Berlongville, &c. One portion is magnetic, the other is not so; this latter part is but partially scluble in acids: that which was dissolved gives in one hundred parts: * (See Lond. and Edinb. Phil. Mag., vol, vi. p. 159.] 432 Prof. Berzelius on Meteoric Stones. Silica: dvises Tackett eetebenee sae’ 9S "OSm Magnesia ..cccsssecsscscessssecesees 36°143 Protoxide of iron ......sseeseeeeees 26°935 Protoxide of manganese ......6.. 0°465 Oxide of nickel mixed with re 0-465 ANC COPPEL .cseeeeeeceeseoeevees A laimiing tien weds zack elaeb ee Ee OR SaS Sota cicncswsieeeeus sleds deca teie bins 29a OOS Potash ccscccresccccccccsccsessevscce | O29 Biosys. dustldc char Sac aaedg sth | RES 100:000 The insoluble part of the non-magnetic portion having been analysed, part by carbonate of barytes and part by car- bonate of soda, affords results which slightly differ: Carb. Barytes. Carb. Soda. Silica: 100:000 100°000 The small globules which are commonly met with in me- teoric stones, which Howard had already observed, and en- deavoured to analyse, were not attracted by the magnet. On examining these globules M. Berzelius found, as had also Howard, that they were not a different description of mineral from the meteorite itself (or that they do not differ from the meteorite in which they occur). The magnetic portion, or the meteoric iron, consisted of, APOM toc ctteusvesesctchssssaaress 4 OO OLO INTHE! aevestvsncescceotrepessecs ©, LOUTS MOGI AE setts Sesest seatseces cep "347 Tin and Copper «c.reccossesece 460 Sulphur ......scseseees sechande "324 Phosphorus, a trace 160°000 The meteorite of Blansko may be considered in a minera- logical point of view as composed of, Prof. Berzelius on Meteoric Stones. 433 An alloy of iron and nickel, containing cobalt, tin, copper, sulphur, and phosphorus ........... 2 2915 Of a silicate of magnesia and protoxide of iron, in which the silica contains as much oxygen as the bases, with a little sulphuret of iron.......... 42°67 Of silicate of magnesia and protoxide of iron, mixed with silicates of potash, soda, lime, and alumina, in which the silica contains twice as much oxy- genas the bases <...scccesevcens ae ad PP OSHS Of chrome and iron mixed with tin-stone..... wah It can hardly be doubted that the relative quantities of the constituent parts of this mixture vary in different fragments of the stone*. Meteoric Stone of Chantonnay.—This stone fell at two o’clock in the morning of the 5th of August 1812, not far from Chan- tonnay, in the department of La Vendée: a fragment was sent to M. Berzelius by the late M. Lucas, a French minera- logist. It is not affected by the magnet, and, like the non- magnetic portion of the Blansko meteorite, contains in 100 parts, 51°12 parts soluble in acids, and 48°88 parts insoluble in these agents. The portion dissolved contained : MEU secparncs vas acap-cepteancesnecanel Oo OO 4 Magnesia secccsscscesccscesceseeeeee 34°357 Proton eG GhAFOID epacdeneccssessare,..25' SOL Protoxide of manganese .......+. $21 Oxide of nickel combined with : ; 456 oxide of copper and tin...... Potash and soda ......0- Solasiemeinae ‘977 GSS) seeeee Sengeasoe cea os ondesseaiere 1:971 100° The portion insoluble in acids is composed of SSUNCH, a oaletaneglnsananep< tain tear etnsnas OG 202 Magnesia ..sccsccsscsecsssersesesees 20°396 WAGs cseitecteca acts'an seis ais cores edenemiees 3°106 BGOLOSIMeCsOF ALON, Secicasstae cacie'naces 9°723 Protoxide of manganese .......... ‘690 Oxide of nickel with oxide of tin and copper .....eeeeseee AIATING, ote sdicsocatcaaceresetcasscne) HlO.OZ> POLL as odcaastaconencusica tp ocindeicsaics 1:000 PGtHSI ocsassanstads sis gavel a veniie oi “512 Chrome and rons ‘spdcccnsseckeosscsten sLLOG L086 “sec ndecccoenctectiealddsiceseedentieae * In this abstract no notice is taken of the protoxide of manganese men- tioned in the analyses of the non-magnetic portion.—J. D. S. Third Series. Yol.9. No. 56. Dec. 1836. 31h 4.34 Prof. Berzelius on Meteoric Stones. M. Berzelius is convinced by later researches, that in this last analysis the quantity of the alloy of chromium and iron ought to be increased to 1°7 per cent., and it also contains about one tenth per cent. of oxide of tin. Meteorite of Loutolor.—This stone fell on the 13th of De- cember 1813, near the village of Lontalax in Finland. It has been described by Nordenskiéld, who presented a fragment of itto M. Berzelius. The magnetic portion is composed of deut- oxide of iron (oxide ferroso-ferrique); the remainder aftords by analysis: In the whole In 100 parts of the quantity. soluble portion. lias cecscacccetetetececeses Peo 37°411 IMEOTIESIR 1c cisccversp acres, OL $2°922 Protoxide of iron......... 32°5 28°610 Protoxide of manganese 9 °793 AN LENIMIANI Lv eniclecteeaiee eee cas 3 “264 Oxides of copper and tin, a trace. Potash and soda ......... a trace. THSOUIIE aeaccuscisccctaves CO 121°5 100° From this analysis it may be concluded, that the portion soluble in acids is a silicate of magnesia and protoxide of iron, probably in reciprocally variable proportions, but in which the silica contains as much oxygen as the bases. The mineral here analysed gives plainly enough the formula fS + 2 MS; nevertheless there is reason to suppose that the atomic pro- portion is accidental, and that meteoric olivine contains these isomorphous silicates in variable proportions. ‘The insoluble part, which is equal to 6°37 per cent. of the weight of the stone, afforded about one per cent. of the alloy of chromium and iron, mixed with oxide of tin, magnesia, lime, protoxide of iron, alumina, and protoxide of manganese, in proportions which appear to indicate that the insoluble portion of this stone has the same composition as the preceding meteorites. Meteoric Stone of Alais.—This stone, which fell near Alais in France on the 15th of March 1806, at half-past five in the afternoon, differs from all the others: it resembles indurated clay and falls to pieces in water, emitting an argillaceous odour. M. Thenard who first examined it, found, besides the general constituents of meteoric stones, some carbon ; this fact was afterwards confirmed by Vauquelin. A small speci- men sent to M. Berzelius by M. Lucas, has afforded to this skilful chemist the opportunity of examining it. One portion (12 per cent.) is attracted by the magnet, which he found was composed of a minute quantity of metallic iron, a little sulphu- Prof. Berzelius on Meteoric Stones. 435 ret of iron, but chiefly of the deutoxide of iron (oxide ferroso- ferrique). This stone when treated with water afforded some organic matter, and 10 per cent. of a salt which con- tained no iron, being a mixture of the sulphates of nickel, magnesia, soda, potash, and lime, with a trace of sulphate of ammonia. ‘The meteorite deprived of its soluble constituents and dried at 212° Fahr., was heated to redness in a small di- stillatory apparatus, and the disengaged gas passed into an in- verted flask filled with lime-water. This operation afforded, Black reside (25. cseeunesiiteted > 8S" E4G Gray-brown sublimate ............ "944 Carbonie acide erieh csi ces. bos PBIB Water’: Siviedieee tha cuceetsitadvecsce J AGLOSS 138°2 parts of the black residue gave by analysis, WHICH, coveanecddecescesidnatecsasscecs, er eariD Maonesia’ .ic..2...cn000 Sense aaters. of DRO Ouids Shane ew. Le fo 8 ray Protoxide of manganese ...... ee 36 PAINT aseeccsstissccsoee eee eee 3°25 Chromium and iron .......cccceees 87 Oxide of tin mixed with copper 1-10 Insoluble carbonaceous residue 12-00 [ess oes See Remi, 3| ahs Ba 4.°4.4. 138°20 The insoluble carbonaceous residue was composed of Carhon wpe lad Beas eae oe 2°586 Chromium mixed with oxide of tin +525 IVE seapeR alt Oo die 2, 012 «earthen to ands *500 Protomde ofaven rei 2 P22 eet. 2°660 Orciterat nickels’. ¥o:.sae so. 3 6 a SNC, 7 VATS ee oe PS ROE oe a *250 Oxide of tin ..... fi ie nenite s%43 uO O BALICAi as sl¥'5:0 ah 5S 3 a Eo epale Stace 4°620 It contained no lime: the magnesia was mixed with a trace of protoxide of manganese, and the oxide of nickel with a trace of cobalt. It is therefore evident that the Alais meteorite is not of the same nature as the foregoing ones. Neither can it be considered as merely a lump of earth. The presence of metallic iron and its sulphuret, and of the oxides of nickel, cobalt, tin, copper, and chromium, which occur: in it, proves that this earth has been formed from the usual meteoric mass, which was in this place ee composed of meteoric olivine. on YZ 436 Prof. Berzelius on Meteoric Stones. So that there can be no doubt that this stone, in spite of the difference of its external appearance, is but a meteorite which in all probability had its origin in the same situation as other meteoric stones. ‘The carbon here occurs in the state of a com- bination, which, when decomposed by heat, affords carbonic acid, either by itself or accompanied by water, and leaves a carbonaceous residue. In the first case the carbon is com- bined only with oxygen, so as to form a body resembling mel- litic acid, but in the latter it is in combination with oxygen and hydrogen. However, there is no other substance known which is not converted into carbon, carbonic acid, and water. It will be perceived by the preceding analyses that the results of M. Berzelius differ a little from those of M. Thenard. Iron and Olivine of Pallas.—This celebrated meteoric mass which Pallas made known in Europe, was discovered lying on the peak ofa schistus mountain in Siberia, between Krasnojarsk and Abekansk. Pallas estimated its weight at 1600 pounds: it was chiefly composed of a skeleton of iron resembling a well- risen loaf, the cavities of which are round and close to one an- other; these are filled with the glassy and greenish olivine, which has been already noticed. According to the analysis of M. Berzelius the iron of Pallas freed from olivine by the hammer, is composed of MEO: sie eheaeeiare aiiiteit kane sisine,: -, BOSD US Wik el es ox cork o5 Pise Cees, baci rae Cy eS Cobalt ..... EEE Rie TY 4.55 Magnesium .:......:+..++ one ‘050 Manganese, «0.000002. Sat "132 Tih and Copper... ss... 0s 066 REAIPSOUL Wes ara kacarciniers are axe aie 043 SOUSMUD Sains ebus 6 bile tg ets a trace Insoluble residue ......... i “480 100°000 This insoluble residue is an extremely interesting part of the meteoric iron, it being precisely the same combination of phosphorus and iron that M. Berzelius has already analysed and described in his Researches on the Meteoric Iron of Bo- humiliz; it is composed of Tren fy tats cece eke eee 48°67 BG AT! Gee sate Tile cite Cement oper MaGnesIARY.). Jiu ce cea acsasis, O00 Phosphorhe: 5205 nie eee POET Dios Files hehin Ge Gerace aah Oe, Prof. Berzelius on Meteoric Stones. 437 M. Berzelius has also found that the iron of Pallas dissolved with heat in an acid slightly diluted, it left, after the solution had become strongly saturated with a neutral salt of iron, a skeleton, of the form of the iron, black, very light and porous, 100 parts of which are composed of Mri’ ei Se ees Saas ene sees Ske eee aren ICEL Cee cee a coos ©6400 Wagnesitniit spcsctiaec.coedag~ tenons 452 Sih and ‘Capper ii seeoc eel. sees tL BTS WATOUI «22s eet ceo ea ccame remot eoee ones “55 100:00 with a slight trace of phosphorus. The presence of magne- sium proves that this metal in combination with iron and nickel is less soluble than iron itself. The olivine of Pallashas been examined by Walmsted and by Stromeyer: the first has found that the composition of this mineral may be exactly indicated by the formula = \ S. The latter, who had met with nickel in other olivines, found, contrary to all conjecture, that the olivine of Pallas contains none, although Howard had already stated it to contain about one per cent. of oxide of nickel. The results of M. Walmsted have been verified by M. Ber- zelius, which is seen on comparing the analyses of these chemists : Walmsted. Berzelius. PHMEH,. « cditgiapin ac stboad piel, 40585 40°86 Mapnesiasensssesssiaccsrsci, 47°73 47°35 Protoxide of iron ...... 11°53 11°72 Protoxide of manganese 0°29 0°43 Oxide OF 41 © sccscseccices ash 100°39 100°53 Two terrestrial olivines, one, that of Boscovich in Bohemia, the other, occurring in masses of lava in the department of Puy-de-Dome, have been subsequently examined by M. Ber- zelius, comparatively with the meteoric olivine of Pallas, and have afforded him, like all the meteoric stones previously examined, oxide of tin mixed with oxide of copper in a quan- tity equivalent to about 0:2 per cent. of the whole mass. Meteoric Iron of Elbogen.—This meteorite, of the flight of which no account exists, but which appears to have fallen to- wards the end of the fourteenth or at the commencement of 438 Prof. Berzelius o Meteoric Stones. the fifteenth century, is now preserved at Vienna. M. Ber- zelius states that the iron of Elbogen is composed of, TON: \scacssecess ow csess boat aneenweases ODIO Mickel? cgunecateciessantaelacceees Peer OOTY, Cobalt. cacsacovensssscbemeshes eect lees "762 Maonesivi ...sscsersssaccssecsness ‘279 Metallic phosphurets.......eeseeeee 2°21 Sulphur and manganese, traces 100:000 The nickel contains tin and copper. The insoluble metallic phosphurets altogether resemble those of the iron of Pallas and Bohumiliz: but it is to those of the latter that they approach the closest in the proportion of the principal constituents ; these are ETON pester carecs ven kepccreeascesaty, LOMTLD Nickel and magnesium ...... 17°72 Phosphorus - In which M and f vary in their relative proportions: it contains as isomorphous substitutes small quantities of the silicates of oxide of nickel and protoxide of manganese, as well as a por- tion of oxide of tin, like terrestrial olivine: it is worthy of remark that it scarcely ever contains lime. 5th. Silicates of magnesia, lime, protoxide of iron, prot- oxide of manganese, alumina, potash, and soda, insoluble in acids, in which the oxygen of the silica is double that of the bases : these probably constitute another mineral, analogous to pyroxéne, M M C /S*; and another, analogous to leucite, 2 S:4+3AS% f K The black crust that covers the surface of meteoric stones is owing to the fusibility of their silicates: these also contri- bute to the fusion of the olivine, which by itself is infusible. That which deserves particular attention is, that if meteoric stones were formed of terrestrial olivine and pyroxene, their colour would be green, or even black, in consequence of the higher degree of oxidation of the iron: this is a sufficient proof that the fused black crust has not been formed in the ter- restrial atmosphere. 6th. Alloy of Chromium and Iron.—It is very remarkable that this mineral so constantly accompanies meteoric stones, considering that it always occurs in such very small quantity. The preceding experiments show that it separates trom the meteorites without alteration, yet it is always partially decom- posed, when it must be sought for in the separated oxide of iron. 7th. Ore of Tin.—The tin of meteoric stones partly pro- ceeds from the native iron they contain, and partly from a small portion of oxide of tin which is disseminated through the chro- miron, and which on analysis dissolves or remains undissolved with the latter body, ‘The oxide of tin is mixed with copper. M. Berzelius considers that a more profound study of meteo- 44:0 Prof. Berzelits on Meteoric Stoites. rites in the point of view from whence he has set out would undoubtedly make known a much larger proportion of their principal constituents. If we consider meteoric stones as mineralogical specimens, and compare them with those of our earth, we shall find essen- tial differences, even putting out of the question the existence of the native iron. The abundance of magnesia which is in all the chief constituent, the poverty in silica, and the small proportion of the silicates of alumina and of the alkalies, distinguish the meteoric minerals. On this earth it is just the contrary: here silica is the predominant substance, and the silicates of alumina and the alkalies form everywhere its prin- cipal constituents. Magnesia is rare. The fineness of grain and feeble cohesion of meteoric stones would lead one to suppose that they are projected in a fused state, and consequently resemble the products of terrestrial volcanos, yet this does not appear to be the case. If we carefully examine the texture of a large fragment of a mete- oric stone, it will be found to be split, and the fissures filled with another kind of mineral, for the most part of a deeper colour, which indicates a slower and calmer formation. If olivine is found amongst the products of terrestrial volcanos, and rarely in other minerals, it is no proof that it must always be a volcanic product. It is infusible, and is found inclosed in volcanic minerals, because it could not be fused with them. On the contrary, in meteoric stones it is so uniformly mixed with the other constituents, that its presence in these is evi- dently owing to another cause which dees not exist in lava and basalt. The Alais meteorite proves that in their original situation rocks are altered by the influence of some geognostic ac- cident, and are converted into a kind of earth, and that even this mass, resembling olivine and mixed with native iron, con- stitutes the rock from which it is broken. ‘The presence, in this earth, of salts soluble in water would seem to prove that this phenomenon had occurred either without the presence of water, or in water which contained such large quantities of these salts that they remained after desiccation. The car- bonized substance that this earth contains, in a state of mix- ture, would not authorize the conclusion that in its original habitat, this earthy substance was of an organic nature. ‘This property of the earth appears, more than any other circum- stance, to show that these meteoric stones have not been pro- jected in a state of fusion and afterwards cooled, for under such circumstances such a formation could not have occurred. The preceding remarks apply to the majority of meteoric Prof. Berzelius on’ Meteoric Stones. 44) stones, which may be regarded as having their origin in the same locality; but three of them afford a composition so essen- tially different from that of the others, that it may be said with certainty that they do not come from the same spot, but ori- ginate in another globe, or perhaps from another part of that globe to which we refer the remainder. These three, however, resemble each other so much that we may assign them a common origin. These are the stones which fell at Stannern in Moravia, and at Jonzac and Juvénas in France. The first was examined by Moser and then by Klaproth; the other two by Laugier. They differ from others in not containing native iron, but constitute an agglomeration of evidently sepa-~ rable minerals, as well as in that the particles of the mixture are of a very small size, and that silicate of magnesia enters into their composition in but very small proportion. They contain, on the contrary, besides a little sulphuret of iron, silicates of lime, alumina, and protoxide of iron, and also some chromium. The proportion between the oxygen of the silica and that of the bases is such that the former is more considerable than the latter, but, however, without being double. About a third of their mass (not including the silica) is, according to the analysis made by Laugier of the meteorite of Juvénas, soluble in acids; from which it may be supposed that in the soluble portion the silica and bases contain an equal portion of oxygen, but that in the insoluble part the oxygen of the former is double that of the latter, as in the meteorites already described. G. Rose has carefully examined this species of meteoric stones, and has rendered it probable that they are mixtures of labra- dor and pyroxene, with a little magnetic pyrites free from nickel, which however, according to his researches, is not at- tracted by the magnet. The following analyses by Klaproth and Laugier show the differences which distinguish these three from other meteoric stones : Stannern. Jonzac. Juvénas. SiMeA will. i aetiaas 43°25 46:00 4.0°0 Magnesia . «= . .. 2:00 1°60 Ss Wome csv sveh sty dhe, 39°50 7°50 9-2 Protoxide of iron 23:00 32°40 23°5 Alumina, .) 0. ++: \ +) 14°50 6:00 10°4 Oxide of manganese... 2°80 6°5 PGBs teas. caks. wsiteadl to wes isa 2 Oxide of copper. . bis | Oxide of chromium ... 1:00 10 Sulphur cay angel) 7245 15°0 0°5 Third Series. Vol. 9. No. 56. Dec. 1836. 3G [ 442. ] LXXXI. On a new Method of preparing Iodous Acid. By Lewis THompson, Esg., Member of the Royal College of Surgeons. To the Editors of the Philosophical Magazine and Journal. GENTLEMEN, SEND you a new method of preparing iodic acid ; it is I cheaper and safer than the process of Sir HumphryDavy, and affords a purer acid than the plan pursued by Gay-Lussac. I say purer, because from some experiments which I have lately made, and intend to repeat more carefully, | am led to conclude with Sir Humphry Davy, that the acid of Gay- Lussac is sulpho-iodic acid. Process for preparing Iodic Acid. Put one atom or 126 grains of iodine into a proper bottle with 24 ounces of water, and pass chlorine, previously washed in cold water, through the mixture until it shall have become colourless ; set the solution aside for an hour; then heat it to 212° Fahr., to disengage the uncombined chlorine, and add 24 atoms or 295 grains of recently precipitated oxide of silver ; boil the whole for ten minutes, filter, and evaporate carefully to dryness: the product is pure anbydrous iodic acid. It will be at once perceived by the above process that there is no such acid as the chloriodic, the acid so called being in fact merely a chloride of iodine, which when dissolved in water is converted into muriatic and iodic acids, with a vari- able quantity of iodine. How this mistake can have passed so long unnoticed is to me a matter of surprise; at the same time I must observe that I have not been able to unite chlo- rine and iodine in the proportions necessary to form these acids without the intervention of water; there is always an ex- cess of iodine: but I have no doubt that this may be effected in a sufficiently reduced temperature. In the last experiment which I made on this subject 50 grains of iodine combined with 41°5 cubic inches or about 30 grains of chlorine: the substance thus formed when put into a large quantity of water, and exposed for some days to the sunshine, deposited 8 grains of iodine and became of a pale yellow colour. That the muriatic and iodic acids exist ready formed in the solution I am confident, not only trom the taste and smell, but because I have obtained free muriatic acid from it by distillation, although when this is continued until the solution becomes a good deal concentrated, these acids react upon each other and produce chlorine and iodine. On a Paradox in the Calculus of Functions. 4.4.3 As the iodate of ammonia is not noticed in any work with which I am acquainted, I think it right to observe here that it is a highly crystalline granular powder, possessed of but little solubility: it may be prepared by saturating the solution of the muriatie and iodic acids with pure ammonia, when it will iall down, the muriate remaining dissolved. I find that iodic acid is decomposed by sulphocyanic acid and the sulpho- cyanates of potash and soda; and also that saliva, in conse- quence probably of the sulpho-cyanate of potash it contains, decomposes iodic acid, and produces with it and starch a blue precipitate not to be distinguished from that produced under similar circumstances by morphia. The importance of this discovery ina medico-legal point of view is considerable, since iodic acid is now very much relied upon as a test for morphia. I am, Gentlemen, yours, &c. Roebuck Place, Great Dover Road, Lewis THompson, Southwark. M.R.C.S. > i ee ee LXXXII. Explanation of a remarkable Parador zn the Cal- culus of Functions, noticed by Mr. Babbage. By Joun T. Graves, Esg., M.A., of the Inner T. emple. [Continued from p. 341, and concluded. } HAVING thus proved that % =1 y yd === COS ————___—4 el V2? oF Vy? + 2 WY + Vered 2 (15.) Vy? + z2 ~ we have seen in what manner it follows that Ege git i eieng ane ee ey Yrut rae G08 0. Vpae is an e-log of x. Q. E. D. 3 2 a5 4% _ ¥ : Let lL vy 424 Vo] rar eo Vp re (which I call the o% e-log of «x of the oth order) be denoted by “(y+ V—12) or lz. Itis plain that when «x is real and positive, 2.x resolves itself in point of quantity (as it ought to do, if our notation be consistent) into the arithmetical] e-log of x. Following the same notation, ] 8 l —_ <= [aig e 1 J 16. VFLa Va, RPE (16.) $G2 444 Mr. Graves’s Explanation of a remarkable Paradox may be denoted by 1, since it may be similarly proved to be an e-log of =, and since it is the same indivi- 4 1 . pe US pide dual function of = that 2a is of x. That it is the same zndi- vidual function (so far as such a phrase can be considered ap- plicable), or in other words, that it has a better right than any : 1 - : other logarithm of =e be considered the logarithm of - corresponding to 1x, will appear on substituting in 7 & the re- : , ! : spective constituents of oo for those of x, that is to say cane for y and pena for z, for by such substitution the expres- sion which I denote by J — will be obtained. : ; 1 ; Observing that in / — the constituent (see (16.)) x 1 oe SN Sse Vypte —l Vy? + 2°, we find 1 he = —Tl/z. (17.) sbtevilas Let 2/7? + 2* = a and —; v= = cos, ='2 5 aud a Vv y+22 yt2 let 71 be denoted by the notation /* @, then, by what precedes, we have “(y+ /=12)orPsr=l VP ae San 18.) i 1 V 32 O+ VA y? ae 32 we have also /(—y'— V —12) or p+ = /yP a ae =1K fey: ea = // y +2%7—Vf—] Wi een Vy? + x but it is easy to see that se pele oq y cos, VS —cos. —=—”——— rece res trl FObes VP aS (20.) H Sg Pe 44/1 ence Px = 1 + 47-1 (21.) in the Calculus of Functions, noticed by Mr. Babbage. 445 ‘\ Yy “ jaa evidently = 7. But /—17 or — V1 x since (one or other of which values V —1 rare am must possess at any time) is an e-log of — 1, for +v¥-17 a ae €o =cos(+7)+ Y¥—1sin(+7)= —1. (22.) Hence, if = be positive, or, x being real, if we choose or have reason to consider the infinitesimal or zero x positive, and if Pay = 1 che i Fda 7, I say that we shall have c v= az, what- ever be c; it being understood that corresponding powers are 1 ze 2 gw to be compared in the expressions eV 7 andc.c¥—!”. Be ie won ok ee For pet ta She =e V-lt —¢, Vl . (23.) but by equation (21.) since = is now supposed positive, P —+ J—iz Px c De be gtr ora Wa. (24.) On the other hand, if z be negatzve, or so considered, and Pex 1 vr= ie 7, we shall no longer have War=cy re but if, —Pr z being negative or so considered, Yv = cV—1*, we may prove in similar manner that equation (1.) will subsist what- ever be c. We have thus therefore obtained two correlated and mutu- ally complemental examples, both possessing, to a certain ex- tent, the property of satisfying (1.), and both of them included —log log « in the generic form ¢'°s(-1), mentioned by Mr. Babbage as derived from the process of Laplace, but in neither case does equation (1.) hold good for all values of 2, positive or negative, nor even for all real values of 2, without an annexed supposition relating to those real values. ‘Thus we see matters so arranged, with most curious delicacy, / 1 that we are never at liberty to suppose Y> = cpu (a 446 Mr. Graves’s Explanation of a remarkable Paradox supposition which it is necessary to make if we would prove? ce? = 1), without making ¥ itself change the form it had when 1 eesti Wy x was equal toc Si in other words, (1.) and (Z.) are es- sentially non-simultaneous equations in the illustrative in- stances before us, for the = of x, of whatever sign it be or be considered to be, though such z be infinitesimal or zero, as in the case of 2 real, is always or must always be considered to [eles be of a different sign from the z of —. When tv x = ov} equation (1.) will not be satisfied for all real quantitative va- lues of x, unless zero be considered positive, nor again when Rex vase sar 7, unless zero be considered negative. Vice versd with respect to equation (Z.). One supposition excludes the other: zero may be considered either positive or negative, but not both together. Hence, even in the case of a real, where the solutions would appear on first view to be concurrent, they are, in truth, alternative. We are bound to consider x the same in state as well as quantity on both sides of the equa- tions (1.) and (2.), and here obscurity arises from the symbols of algebra not expressing to the eye a difference of state be- tween reals having the same quantity. Such difference of state in things denoted by algebraic symbols is in most cases immaterial, unless no quantity remain in either of their con- stituents; but we know that it is of importance in the case of vanishing fractions, and we perceive that it may become so in certain other fine circumstances, such as those which we have just discussed. We have shown therefore by a particular example (or ra- ther by two correlated examples) that the paradox noticed b Mr. Babbage is only a remarkably subtle instance of the fol- lowing general proposition which is not @ prior? improbable. Though we may prove it to be impossible to find one fixed form Y, such that the equation ) 2 = Faz (F and « being given functions) shall hold good simultaneously in different cases where particular values of w are assumed (the term ‘* value” including state as well as quantity), we are not there- fore to despair of finding distinct forms of ¥, absolute or al- ternative, which for certain values of x, within appropriate limits, shall severally satisfy the equation ) «= FWa.z. Such a partial form of x and the corresponding partial form of F Yaa taken with it may be likened to two curves which co- in the Calculus of Functions, noticed by Mr. Babbage. 44:7 incide for a certain continuous space and divaricate in the rest of their course. Those parts of this paper in which znfinitestmals have been spoken of in the more popular language of mathematics, may advantageously be translated into the more rigid phrase- ology of Jimits. Various distinct continuities may terminate in the same quantity as a limit, as, for example, a line may be looked upon as having moved through any of the in- finite number of planes of which it may be the boundary, and it is easy to conceive that there are properties of such a line, which (all things else remaining the same) vary with the plane in which its motion is deemed to have taken place ; but it is, I believe, a novelty in algebra, to present an instance of a given individual function of a positive or negative quantity, which varies accordingly as the functional subject is regarded as the limit of this or that kind of imaginary quantity. Professor De Morgan, in the place before cited, (p. 335.) men- ti (; — ions {7 nuous that appears to satisfy equation (1.) independently of c. We mayassume thatal ways on the opposite sides of that equation aa) _ is intended to denote the same quantity, and thatin the log ec *) log(— 1) as a form of | x not obviously disconti- ” log c ] f log ¢ 1 — x\!og(- 1) bags log (— 1) expressions (ae a *) and ¢ Fa corre- + = x sponding powers are to be compared. With respect to this instance I shall only add that it would not be difficult to show by reasoning similar to that which I have already employed in this paper, that no definite case included in the indeterminate log c ; i mye ip expression can be other i p ( ry than a partial or alternative solution for a2, unless c? = 1; for let nae +x =y+¥-—1z, then it may be proved by my exponential theorems that the equation Pe Hl Ligsslog € (: = ied 1 — —\ log (= 1) l+e2 re a3 - 1+ z if, being individualized, it hold good for x of one sign posi- 348 Mr. Graves’s Explanation of a remarkable Paradox tive or negative, cannot hold good for z of an opposite sign, 1 unless c= —. c Inner Temple, July 1836. P.S. It is not out of place to mention, that I am gratified with the view which Professor De Morgan has taken in the last Number of this Magazine (October 1836, vol. ix. p. 252,) of my researches on logarithms, and that I agree with him in considering my results rather upon the whole as extensions or (as I should say) completions, than as corrections of what had before been accomplished. He has also properly noticed an oversight I committed in not observing the distinction he drew in his Calculus of Functions, with reference to the possi- bility of obtaining the most general solution, between func- tional equations where there are and where there are not in- dependent variables. I may be permitted, however, to assent to his remarks on some other points with some qualifications, which may seem over-nice and pedantic, but are required by the delicacy of the subject, and I wish to prefix some expla- nation relative to the actual progress or improvement which I consider this branch of science to have received from my researches. ‘The deficiencies in the ordinary theory which I have endeavoured to supply are the following: first, [found no formula which assigned even one value of a, much less all of them, when a and « were imaginary; secondly, I considered that as —2 was a value of 43, 4 would be admitted to be, or at least deserved to be reckoned a logarithm of —2 to the base 4, and yet in no formula which I had met with for the 4-logs of —2 was any such quantity as } included; thirdly, I observed generally great laxity, not to say inaccuracy, in the use of ambiguous exponential expressions, and saw equations employed without apparent restriction where, perhaps, the two sides had but one value in common. For instance, the equation eltV—-12m7= ¢ is not correct without restricting the meaning of the left-hand side, for though every quantity included in the formula 1 + VW —12m0 is an e-log of e, el +/—12m7 has an infinite number of real values besides e for any given m, except m= 0. Hence, | scruple to call e1+”—12m 7 merely a general algebraic form of e, and think it necessary to devise a notation to characterize that particular value of e!+ 7 —12mz which is equal to e. 1+ /=12 mor The still more general form e 1+” Tins has, equally in the Calculus of Functions, noticed by Mr. Babbage. 449 with e!+ /—-12m=, one of its values equal to e, and is the most general exponential form that possesses this property; a pro- perty which seems to me, even according to ordinary accep- tation, to confer on every quantity included in the formula 1+/—-12m-7 1l+Y/-12n_7 let me remark that I cannot conceive how any difference in re- sults can be obtained from operating correctly on two strictly equivalent algebraic forms such as cos § and cos (2im + 4). It is true that one may suggest what we have to recollect with respect to the other, and it is true that in the treatment of such forms there are many specious fallacies to be guarded against. Thus, it would not be correct to reason as though cos {c(2ia+ 4)} were the same function of cos (Qin + 4) that Cos (c§) is of cos 6, if 4 denote a particular individual value of cos~!cos@. On account of the preceding considera- tions, among others, instead of obtaining my formula for 2, the general logarithm of y, by the method stated by Professor De Morgan as substantially the same as mine, viz. by setting a right to the appellation e-log of e. Here out at once with the unelementary definition ¢ 1+ V—12m)z = elytV—l2ne T should prefer building, as I have done, on received principles of analogy, which, I think, would na- turally entitle Py to the name of an e-log of y, if any value of a¥” were equal to y, especially if we found that Wy pos- sessed the property Vy+y = YVyy’. I do not meet in books any explicit exclusion of § from the name of logarithm of —10 to the base 100 on the ground that —10 is not what is called the arithmetical value of 100%, and, in legal phrase, I sub- mit that the onus of making out their case lies on those who advocate such an exclusion. It would refuse the name of logarithm to any function whatever of y, where y and the base a were not real and positive, or would require some definition of what is meant by the arithmetical value of a? for all values of a and 2, as well imaginary as real. Now, for some values of a, it may be matter of arbitrary decision to determine which one of a certain pair of values of a” is to be considered as corresponding to that which is the arithmetical value of a’, the when @ and x are real and positive. Is ,/—1 or WW isis arithmetical value of (—1)2? For some values of a and 2, a* has more than one real positive value, and for some, again, a@* has a single real positive value corresponding to Third Series. Vol. 9. No. 56, Dec. 1836. 3H 450 Dr, Inglis on the Electrical Conducting Power of Iodine. what would be in general an imaginary value of a*, if a and x were real and positive. But I have already occupied too much space, and need not labour these arguments, for Pro- fessor De Morgan does not materially differ from me here. He seems to regard the ordinary theory as an edifice com- plete in itself, but is content to receive my results as an ex- tension which may prove useful, whereas I regard them rather as the erection of a wing, required for symmetry, if not for use. —— LXXXIII. On the Conducting Power of Iodine for Electricity. By James Ineuis, M.D.* [Addressed to the Chemical Section of the British Association. ] [? may not, perhaps, have escaped the notice of some of the members of this Section, that in extracts froma Prize Essay of mine, published some months ago, in the Philosophical Ma- gazine, I stated that I had found iodine to be a conductor of electricity. Nor may the experiments of Mr. Solly tending to prove the contrary have passed by unobserved. Nevertheless, being satisfied in my own mind what I had published was correct, 1 determined at the earliest opportunity to resume the investiga- tion, and instead of answering that gentleman directly through the medium of the Philosophical Magazine, I thought it might be better to lay before you the result, in as much as I shall by experiment prove my former statement, and then furnish you with that portion of iodine which you have seen conduct, that you may for yourselves judge of its purity. In Mr. Solly’s first paper, no mention is made of experi- ments performed with fused iodine; but his attention being drawn to the subject by a note of mine, he published a second, in which he throws a doubt on the purity of the iodine I had used, saying that it contained “ most probably the iodide of iron, which is not unfrequently present in the iodine of the shops.” (Lond. and Edinb. Phil. Mag., No. 48. p. 401.) The iodine I used was obtained from the manufactory of Mr. Whitelaw of Glasgow, where no iron vessel is ever em- ployed, and in which, in its veriest impurity, no iron can be detected. Here, for instance, is one tube containing an aqueous solution of ioduret of iron; a second, an aqueous solution of the iodine to be tested; and a third having im it a solution of the ferrocyanate of potassa. Now, on adding a small portion of this last solution to the one containing iron, immediately the blue ferrocyanate of the peroxide of iron re- sults. But no such effect is produced when the test is added * Read before the Chemical Section of the British Association at Bristol, Aug. 26, 1836; and now communicated by the Author. Dr. Inglis on the Electrical Conducting Power of Iodine. 45\ to the solution of iodine; it remains the same as before admix~ ture. Add, however, but a single drop of the solution of the ioduret of iron and the blue colour instantly appears. But sup- pesing that a small portion of the ioduret by some chance happened to be present, we know that from its great affinity for water it could be removed by washing; I therefore washed several times, and thoroughly dried, the iodine with blotting- paper; and lastly, thrice sublimed it; so that now I presume it is as pure as possible. Of this iodine thus prepared, [ put a portion into a tube with a platinum wire hermetically sealed into one extremity ; and introducing a second wire at the other till one end ap- proached the former to within about the fourth of an inch, I hermetically sealed this extremity also: so that we have here a closed tube containing dry pure iodine, with two se- parate platinum wires communicating together only through the medium of the iodine. Three galvanic troughs, containing each 30 pairs of plates, were charged, (but 20 pairs, or fewer, as in the trough now to be used, are sufficient,) and one of the platinum wires fixed to the positive pole, whilst the other was placed in a glass of acidulated water. On forming the galvanic circle, no effect was produced, either by the decomposition of water, or by sensation on the tongue: nor was there any difference on re-~ versing the poles. The iodine being now liquefied by the flame of a spirit-lamp, and the tube attached to the negative pole, the platinum wire was placed as before in water; and on completing the circle by a copper wire from the positive, instantly bubbles of gas appeared and were evolved at the platinum wire, whilst none appeared at the copper, being positive. ‘The order be- ing reversed, globules of gas appeared at both wires, showing clearly that decomposition had been effected. Again, if the platinum wire be placed on the tongue, and the copper wire be taken hold of with the hand, instantly the galvanic sensation is felt. The heat being removed, the power of conduction gradually dies away; so that in seven minutes it is incapable of transmitting even sufficient electricity to be perceived by the tongue. When therefore I stated in a note attached to Mr. Solly’s paper, that iodine when cold and concrete still con- ducted, I was in error, being led to say so from recollection only. But my general statement that iodine is a conductor, is, I hope, satisfactorily shown to be borne out this day by ex- periment. = Dr. Cumming considered that the conduction might be 3H2 452 The Rev. J. W. MacGauley on some remarkable Results explained by the fact made known by Mr. Faraday, that air when heated becomes a conductor. But that could not apply here, for in the first place, it is not air at all that is the me- dium of conduction, it is /igu¢d iodine; and in the second, on melting the iodine and inverting the tube the conduction is suspended. Dr. Apjohn now suggested that the iodine at the tempera- ture required for its liquefaction might act on the platinum, and that an ioduret of platinum thus formed would conduct. But iodine does not act on platinum at 225° Fahr., and 225° is the point at which iodine fuses. This I stated at the time the objection was made, and since my return I have accurately weighed a piece of platinum wire, and allowed iodine to act on it for half an hour, at and above the point of fusion; when on weighing again, the platinum wire was found to have lost nothing ; so that Dr. Apjohn’s objection thus loses its weight, no ioduret having been formed. The conducting power of iodine, atmospheric air, and some other substances when heated, and their non-conducting when cold, adds, I think, an argument in favour of that theory which considers electricity to be but an action of matter; and heat and electricity to be but modifications of each other. Castle Douglas, Oct. 3, 1836. JaMEs INGLIS. LXXXIV. An Account and Explanation of some remarkable Results obtained during a Course of Electro-Magnetic Expe- riments. By the Rev. J. W. MacGavutey*. jt is impossible not to remark that the electro-magnetic he- lix seems to increase the power of a given battery, for the brilliancy of the spark increases with the magnitude of the ap- paratus. I expected that such an intensity might be given by a very powerful electro-magnet, as that a small galvanic ar- rangement anda single circle might be made to communicate a considerable shock. I coiled nearly 2000 feet of copper wire, in ten helices, upon a bar of soft iron, during the experiments I was making preparatory to the construction of a large and greatly improved machine on the principle which I exhibited last year (1835) to the British Association, and which is now nearly completed: from this magnet I obtained a powerful shock. It is not necessary to detail a great variety of arrangements adopted and results obtained; among others I came to the fol- lowing conclusions: * Read before the Royal Dublin Society on June 14th; and now com- munieated by the Author, of Electro-magnetic Experiments. 453 Ist. That the spark and shock obtained from an electro- magnet, on breaking battery communication, are not the spark and shock of the battery nor of the electro-magnet, but, most probably, the electricity induced on the wire of the helix by the electricity of the battery, or, if it be true that a current passes along the wire, the electricity intercepted in its passage from the copper to the zine. 2nd. That the spark and shock do not depend, except within certain limits, on the size of the battery. 3rd. That they confirm what I ventured to assert at the last meeting of the British Association (1835) on the nature of mag- netism. 4th. That the real power of the battery is not increased but diminished by the electro-magnetic, or rather, electro-galvanic helix. Ist. The spark and shock (the latter of which I do not re- collect to have seen remarked before,) obtained with an elec- tro-magnet on breaking battery communication, are not the spark or shock of the battery, for neither one nor the other can exist until after battery communication is actually broken. Again, if they arise from the battery, to receive the shock it would be necessary to form a part of the communication be- tween the copper and zinc. This, however, is not required ; it is necessary only to form a part of the communication be- tween the extremities of the helix, or between one extremity of the helix and either the copper or zinc of the battery. Neither does the shock or spark arise from the influence of the bar of soft iron inclosed in the helix: on the contrary, the retention of magnetism in the bars, either from the nature of its iron or the action of a keeper, will proportionably diminish the effect ; and I have no doubt that if a large portion of mag- netism were retained in a powerful electro-magnet by the keeper, and the keeper were torn off with violence from the magnet, a shock and spark would be perceived at the mo- ment of disruption, which, together with those obtained when battery communication was broken, would form a spark and shock exactly equal to what were obtained had there been no retention of magnetism by the keepers when battery commu- nication was interrupted. Of the apparatus submitted to the Society for the purpose of demonstrating the facts contained in this paper by experi- ment, the part to which it was desired more particularly to di- rect attention consisted of 588 feet of copper wire, No. 13, coiled in seven helices of 84 feet each, on a thin brass tube, 54 inches in length, ? internal diameter, having discs of brass, 4, inches in diameter, attached to its extremities. The tube 454 The Rev. J. W. MacGauley on some remarkable Results and discs were intended merely as a convenient means of coil- ing the wire and submitting bars of iron or of steel to the ac tion of the helix. The corresponding extremities of the coils were soldered to two thick pieces of copper wire, which weré made to dip respectively into two cups of mercury, forming a connexion between the poles and a calorimotor 1 foot square, double cell, charged with 400 drachms of water and 12 of muriatic acid. Wires lead from the same cups of mercury to vessels containing a solution of common salt, into which the hands are dipped for the purpose of obtaining a shock when battery connexion is broken. ‘Though the wire, for conve- nience, is coiled upon brass, it is immaterial how it is ar- ranged. I have thrown it into a heap, and believe the effect was equally powerful. The spark and shock must be produced after battery com- munication is broken, because while it exists, every electrical effect must be prevented by the helix, as it affords a good con- ducting communication between the copper and zine of the battery. Inclosing a bar of soft iron in the helix diminishes the effect. and. The size of the battery, only within certain limits, af- fects the spark and shock. In constructing a galvanic helix, or a system of such helices, it is evident that the length of the wire must be limited, on account of its imperfect con- ducting power. We must therefore, to produce a consider- able effect, multiply the helices: on the other hand, if the bat tery be very small, a minute subdivision of its electricity among so many wires may render the portions in each insufficient for any considerable disturbance of electrical equilibrium. The number of the coils and their lengths must therefore be regu- lated: by the size of the battery and the conducting power of the wire. 8rd. Those properties of the electro-galvanic helix are strongly confirmatory of the theory I ventured to advance be- fore the British Association on the nature of magnetism: “That its existence does not depend on the continuance of electrical currents; that continued electrical currents are not the consequence of magnetization ; and that magnetism is mere electrical excitement.” For if electrical currents were essen- tially connected with magnetism, and if we can obtain a shock and spark—the acknowledged indications of a current by a simple helix—how much more should we obtain these indica- tions when both causes are simultaneously in action, either of which, of itself; were sufficient for their production! Yet the existence of magnetism within the helix proportionably injures its effect. Magnetism is merely induced electricity, for it is of Electro-magnetic Experiments. 455 produced by the action of an excited helix. The action of an excited body is the production of an opposite excitement on any body in its proximity, which induction increases its own capacity for electricity. Supposing magnetized substances to be merely modified instances of this seemingly universal law, all their properties may easily be explained. 4th. The power of the battery is not increased, but dimi- nished, by the helix; for, after passing through one helix, its power of exciting another is lessened, nor will it affect a gal- vanometer so much, If it were increased, judging by the spark and shock, and supposing these to arise from such increase, it ought to have acquired an intensity which would easily carry it through any length of wire. When 400 drachms of water and 12 of muriatic acid were used, the effect was transitory ; but the spark was very brilliant with the helix alone, less brilliant with a magnet having 12 feet more wire than the helix, less still with a smaller magnet. The shock with the Aelzz was stronger than with the larger magnet; but when 400 drachms of water, 8 of sulphuric acid, and # of nitric acid were used, the spark from the helix re- mained the most brilliant, but the shock from the magnet be- came stronger than from the helix. To get a shock at a maxi- mum from the helix, contact must be rapidly broken; from the magnet, slowly. The magnet had 600 feet of wire coiled in three helices; the helix 588 feet in seven coils. The shock was considerably increased when two persons dipped their hands into the vessels containing the solution of salt; at the same time each received a greater shock than when only one . person formed the communication. If the mercury be not clean, or if some of the battery charge be found upon its surface, neither shock nor spark will be ob- tained, because as soon as the wire leaves the mercury, con- tact for the battery, as its electricity is of very low tension, ceases; but the other fluid will conduct away the electricity, from whence arise the shock and spark. If one extremity of the helix, or one wire of the battery, be lifted out of the mer- cury in contact with the wire leading from the same cup to the solution of salt, no shock will be felt. A very cheap, permanent, and convenient apparatus, on the same principle as that submitted to the Society, may be con- structed; one which would bear to the galvanic battery of a single circle the same relation as the Leyden jar to the elec- trical machine. Like the Leyden jar, it may be made a ma- gazine of power, ready to be exerted on any object the expe- rimenter may desire; but it is not frail and perishable, does not demand much care nor attention, does not depend on the 456 On the Art of Glass- Painting. state of the atmosphere for its efficiency, nor require almost any expense to produce or continue its actions. To construct it, however, on a large scale, a considerable quantity of wire, covered with an insulating substance, is re- quired. The covering of the wire is at present, I believe, ex- pensive, but a machine I constructed for the purpose, which leaves nothing to the care or skill of the operator, almost no- thing to his labour, and which may be applied to many branches of manufacture, has changed what would otherwise be trouble- some and laborious into the work of a few moments. Some judgement may be formed of the rapidity of its execution when I mention that very lately I covered with it 20,000 feet of wire of various diameters; and of the ezactness with which it covers it, by the nearly 1300 feet employed in the apparatus submitted to the Society. 79, Marlborough Street, Dublin, June 16,1836. LXXXV. On the Art of Glass-Painting. By A CorresPonveEnNT. S the accounts to be found in various works respecting this curious art are by no means satisfactory or complete, I have thought that a few observations on the subject, com- prising a concise account of the processes employed, both in ancient and modern times, might be deemed of sufficient in- terest to obtain a place in the Lond. and Edinb. Philosophical Magazine. It is a singular fact, that the art of glass-painting, prac- tised with such success during former ages from one end of Europe to the other, should gradually have fallen into such disuse, that in the beginning of the last century it came to be generally considered as a lost art*. In the course of the eighteenth century, however, the art again began to attract * (Our Correspondent will doubtless be glad to learn that a very able and interesting work on Glass-Painting has jately been published at Rouen, entitled, ‘‘ Essai Historique et Descriptif sur la Peinture sur Verre ancienne et moderne, et sur les Vitraux les plus remarquables de quelques monumens Frangais et étrangers; suivi de la Biographie des plus célébres Peintres- Verriers: Par E.H. Langlois, du Pont-de-l’Arche, orné de Planches des- sinées et gravées par Mademoiselle Esperance Langlois, 1832.” The beau- tiful and curious windows of the churches of St. Godard, the Cathedral, St. Ouen, St. Patrice, and St. Vincent in Rouen have been copied by Ma- demoiselle Langlois with great spirit, skill and faithfulness. M. Langlois disproves the notion (“|’aveugle préjugé”’), that the art had been lost, p. 193; and states that this error was more unaccountable in England, where, according to one of the memoirs of M. Al. Brongniart, a number of the finest windows were painted from 1616 to 1700, and by Jervis Forrest up to 1785.—R. T.} On the Art of Glass-Painting. 457 attention, and many attempts were made to revive it. It was soon found by modern artists, that by employing the pro- cesses always in use among enamel-painters, the works of the old painters on glass might in most respects be successfully imitated; but they were totally unable to produce any imita- tion whatever of that glowing red which sheds such incom- parable brilliancy over the ancient windows that still adorn so many of our churches*. For this splendid colour they possessed no substitute, until a property, peculiar to silver alone among all the metals, was discovered, which will pre- sently be described. ‘The art of enamelling on glass differs little from the well-known art of enamelling on other sub- stances. The colouring materials (which are exclusively me- tallic) are prepared by being ground up with a flux, that is, a very fusible glass, composed of silex, flint-glass, lead, and borax: the colour with its flux is then mixed with volatile oil, and laid on with the brush. The pane of glass thus ena- melled is then exposed to a dull red heat, just sufficient to soften and unite together the particles of the flux, by which means the colour is perfectly fixed on the.glass. ‘Treated in this way, gold yields a purple, gold and silver mixed a rose- eolour, iron a brick-red, cobalt a blue}; mixtures of iron, copper and manganese, brown and black. Copper, which yields the green in common enamel-painting, is not found to produce a fine colour when applied in the same way to glass, and viewed by transmitted light; for a green therefore re- course is often had to glass coloured blue on one side and yellow on the other. ‘To obtain a yellow, silver is employed, which, either in the metallic or in any other form, possesses the singular property of imparting a transparent stain, when exposed to a low red heat in contact with glass. This stain is either yellow, orange, or red, according to circumstances. For this purpose on flux is used: the prepared silver is merely ground up with ochre or clay, and applied in a thick layer upon the glass. When removed from the furnace the silver is found not at all adhering to the glass; it is easily scraped off, leaving a transparent stain, which penetrates to a certain depth. Ifa large proportion of ochre has been employed, the stain is yellow; if a small proportion, it is orange-coloured ; and by repeated exposure to the fire, without any additional * In 1774 the French Academy published Le Vieil’s treatise on Glass- painting. He possessed no colour approaching to red, except the brick- red or rather rust-coloured enamel subsequently mentioned in the text, de- rived from iron. : + It appears by2a boast of Suger, abbot of St. Denis, which has been preserved, that the ancient glass-painters pretended to employ sapphires among their materials; hence, perhaps, the origin of the term Zaffres, under which the oxide of cobalt is still known in commerce, Third Series. Vol. 9. No. 56. Dec. 1836. 3 I 4.58 On the Art of Glass-Puinting. colouring matter, the orange may be converted into red. This conversion of orange into red is, I believe, a matter of much nicety, in which experience only can ensure success. ‘Till within a few years this was the only bright red in use among modern glass-painters; and though the best specimens cer- tainly produce a fine effect, yet it will seldom bear comparison with the red employed in such profusion by the old artists *. Besides the enamels and stains above described, artists, whenever the subject will allow of it, make use of panes co- loured throughout their substance in the glass-house melting- pot, because the perfect transparency of such glass gives a brilliancy of effect, which enamel-colouring, always more or less opake, cannot equal. It was to a glass of this kind that the. old glass-painters owed their splendid red. This in fact is the only point in which the modern and ancient processes differ, and this is the only part of the art which was ever really lost. Instead of blowing plates of solid red, the old * [The barbarous devastations to which the productions of this beautiful art have been subjected are deeply to be regretted. It appears from the interesting “ Account of Durham Cathedral ” lately published by the Rev. James Raine, that there was much fine stained glass in the fifteen windows of the Nine Altars which “ shed their many-coloured light Through the rich robes of eremites and saints ;” until the year 1795, when ‘their richly painted glass and mullions were swept away, and the present plain windows inserted in their place. The glass lay for a long time afterwards in baskets on the floor; and when the greater part of it had been purloined the remainder was locked up in the Galilee.’ And in 1802 a beautiful ancient structure, the Great Vestry, “ was, for no apparent reason, demolished, and the richly painted glass which decorated its windows was either destroyed by the workmen or afterwards purloined.”” The exquisite Galilee itself had been con- demned, but was saved by a happy chance. The destruction of these “storied windows, richly dight, Casting a dim religious light, has not then been the work of the calumniated cotemporaries of cur divine poet, but of the successive Deans and dignitaries of the Church. And if Painting and Architecture have to complain of such devastation in our ca- thedrals, the treatment of the sister art has been still more deplorable. The ample funds with which the Choirs were endowed, as distinct corpora- tions established for the cultivation of the highest species of sacred music, and its employment in divine worship, having been misappropriated by pri- vate cupidity, no longer does “ the pealing organ blow To the fudl-voiced quire below,” but to perhaps a third of the complement prescribed by the statutes, and those often too ill paid and inefficient to realize the poet’s beautiful de- scription. As for“service high,” in many cathedrals it is quite out of the ques- tion, as very few of the minor canons, are musicians and the choirs, instead of being ‘‘ full-voiced,” are reduced to the lowest number by which the skeleton or outline of the cathedral service can be exhibited. But bad as these things are, the proposed changes, in the hands of ignorance and barbarism, may yet be for the worse, and the choirs, having been now brought to the On the Art of Glass-Painting. 459 glass-makers used to flash a thin layer of red over a sub- stratum of plain glass. Their process must have been to melt side by side in the glass-house a pot of plain and a pot of red glass: then the workman, by dipping his rod first into the plain and then into the red glass pot, obtained a lump of plain glass covered with a coating of red, which, by dexterous ma- nagement in blowing and whirling, he extended into a plate, exhibiting on its surface a very thin stratum of the desired colour*. In this state the glass came into the hands of the glass- painter, and answered most of his purposes, except when the subject required the representation of white or cther colours on a red ground: in this case it became necessary to employ a machine like the lapidary’s wheel, partially to grind away the coloured surface till the white substratum appeared. The material employed by the old glass-makers to tinge their glass red was the protoxide of copper, but on the dis- continuance of the art of glass-painting the dependent manu- facture of red glass of course ceased, and all knowledge of the art became so entirely extinct, that the notion generally pre- vailed that the colour in question was derived from gold +. It is not a little remarkable that the knowledge of the cop- per-red should have been so entirely lost, though printed re- ceipts have always existed detailing the whole process. Bat- tista Porta (born about 1540) gives a receipt in his Magia Naturalis, noticing at the same time the difficulty of success. Several receipts are found in the compilations of Neri, Merret and Kunckel, from whence they have been copied into our Encyclopzedias{. None of these receipts however state to what purposes the red glass was applied, nor do they make any mention of the flashing. The difficulty of the art consists in the proneness of the copper to pass from the state of prot- lowest ebb, finally extinguished. With regard to our national and ecclesies- tical monuments, we would hope that these may no longer be left at the mercy of chapters and churchwardens, but put nnder the protection of men of taste and of professional skill empowered to watch over their preservation and to administer the funds devoted to the purpose.—R. T.] * That such was the method in use, an attentive examination of old specimens affords sufficient evidence. One piece that I possess exhibits large bubbles in the midst of the red stratum; another consists of a stratum of red inclosed between two colourless strata: both circumstances plainly point out the only means by which such an arrangement could be produced. + In 1793, the French government actually collected a quantity of old red glass, with the view of extracting the gold by which it was supposed to be coloured! Le Vieil was himself a glass-painter employed in the repair of ancient windows, and the descendant of glass-painters, yet so little was he aware of the true nature of the glass, that he even fancied he could detect the marks of the brush with which he imagined the red stratum had been laid on ! {(M. Langlois names the following writers : *‘ Neri en 1612, Handicquer de Blancourt en 1667, Kunckel en os La Vieil en 1774, et plusieurs Bui-Z 460 On the Art of Glass-Painting. oxide into that of peroxide, in which latter state it tinges glass green. In order to preserve it in the state of protoxide, these receipts prescribe various deoxygenating substances to be stirred into the melted glass, such as smiths’ clinkers, tartar, soot, rotten wood, and cinnabar. One curious circumstance deserves to be noticed, which is, that glass containing copper when removed from the melting- pot sometimes only exhibits a faint greenish tinge, yet in this state nothing more than simple exposure to a gentle heat is requisite to throw out a brilliant red. This change of colour is very remarkable, as it is obvious that no change of oxy- genation can possibly take place during the recwisson. The art of tinging glass by protoxide of copper and flashing it on crown-glass, has of late years been revived by the Tyne Company in England, at Choisy in France*, and in Suabia in Germany, and in 1827 the Academy of Arts at Berlin gave a premium for an imperfect receipt. ‘To what extent modern glass-painters make use of these new glasses Tam ignorant; the specimens that I have seen were so strongly coloured as to be in parts almost opake, but this is a defect which might no doubt be easily remedied f. I shall now conclude these observations by a few notices respecting glass tinged by fusion with gold, which, though never brought into general use among glass-painters, has I know been employed in one or two instances, flashed both on crown-and on flint-glass. Not long after the time when the art of making the copper-red glass was lost, Kunckel ap- pears to have discovered that gold melted with flint-glass was capable of imparting to it a beautiful ruby colour. As he derived much profit from the invention, he kept his method secret, and his successors have done the same to the present day. The art, however, has been practised ever since for the purpose of imitating precious stones, &c., and the glass used to be sold at Birmingham for a high price under the name of Jew’s glass. ‘The rose-coloured scent-bottles, &c., now com- monly made are composed of plain glass flashed or coated autres écrivains a diverses époques, decrivaient ces procédés.” (p. 192.) He fixes the restoration of the art in France at about the year 1800, when Brongniart, who had the direction of the Sévres porcelain manufacture, worked with Méraud at the preparation of vitrifiable colours. p. 194. Among modern artists he particularly mentions Dihl, Schilt, Mortelégue, Robert, Leclair, Collins, and Willement.—R. T.] * Bulletin de la Société d’ Encouragement pour ? Industrie Nationale, 1826. + Though it is difficult to produce the copper-glass uniformly coloured, it is easy to obtain streaks and patches of a fine transparent red. For this purpose it is sufficient to fuse together 100 parts of crown-glass with one of oxide of copper, putting a lump of tin into the bottom of the crucible. Metallic iron employed in the same way as the tin throws out a bright scarlet, but perfectly opake, On the Art of Glass- Painting. 461 with a very thin layer of the glass in question. I have myself made numerous experiments on this subject, and have been completely, and at last uniformly, successful, in producing glass of a fine crimson colour. One cause why so many per- sons have failed in the same attempt*, I suspect is that they have used too large a proportion of gold; for it is a fact, that an additional dose of gold, beyond a certain point, far from deepening the colour, actually destroys it altogether. An- other cause probably is, that they have not employed a suffi- cient degree of heat in the fusion. I have found that a de- gree of heat, which I judged sufficient to melt cast-iron, is not strong enough to injure the colour. It would appear, that in order to receive the colour, it is necessary that the glass should contain a proportion either of lead, or of some other metallic glass. I have found bismuth, zinc, and anti- mony to answer the purpose, but have in vain attempted to impart any tinge of this colour to crown-glass alone. Glass containing gold exhibits the same singular change of colour on being exposed to a gentle heat, as has been already noticed with respect to glass containing copper. The former when taken from the crucible is generally of a pale rose-colour, but sometimes colourless as water, and does not assume its ruby colour till it has been-exposed to a low red-heat, either under a muffle or in the lamp. Great care must be taken in this operation, for a slight excess of fire destroys the colour, leaving the glass of a dingy brown, but with a blue transpa- rency like that of gold-leaf. These changes of colour have been vaguely attributed to change of oxygenation in the gold; but it is obviously impossible that mere exposure to a gentle heat can effect any chemical change in the interior of a solid mass of glass, which has already undergone a heat far more intense. In fact I have found that metallic gold gives the red colour as well as the oxide, and it appears scarcely to admit of a doubt, that in a metal so easily reduced, the whole of the oxygen must be expelled long before the glass has reached its melting point. It has long been known that silver yields its colour to glass while in the metallic state, and everything leads one to suppose that the case is the same as to gold. There is still one other substance by means of which I find it is possible to give a red colour to glass, and that is a com- pound of tin, chromic acid, and lime; but my trials do not lead me to suppose that glass thus coloured will ever be brought into use. * Dr. Lewis states that he once produced a potfull of glass of beautiful colour, yet was never able to succeed a second time, though he took in- finite pains, and tried a multitude of experiments with that view.—Com- merce of Arts, p.177. [ 462 ] LXXXVI. Observations on some of the Fossils of the London Clay, and in particular those Organic Remains which have been recently discovered in the Tunnel for the London and Birmingham Railroad. By Natu. 'THomas WETHERELL, Esq., F.G.S., MRCS, §c.* ROM the number of railroads now in progress in dif- ferent parts of this country, and the necessary excavations required in the making of them, there probably never was a time more favourable to the researches of the geologist than the present; and it is sincerely to be hoped that no spot will remain untouched, the examination of which holds out a pro- spect of adding to our knowledge of the strata of the earth. It is my intention in the following memoir to notice more par- ticularly those remains of the London clay which I have re- cently collected from that portion of the London and Bir- mingham railroad which passes in the immediate neigh- bourhood of Chalk Farm. I shall, however, occasionally ad- vert to discoveries made in other parts of this important and highly interesting formation, which, having closely examined it in different places, I find contains many minute and exceed- ingly curious fossils, well worthy the attention of the naturalist. Before proceeding to a detail of the organic remains, it may be as well to give a short sketch of the relative position and appearance of the clay here, although there may be no per- ceptible difference from other places where this stratum has been exposed. Immediately beneath the vegetable mould is a thin bed of diluvium, containing a few bones of animals; and below this is the London clay, which may be easily traced along the line of road, from Chalk Farm to a field in front of Mornington-place, Hampstead road. This portion pre- sents to the eye a reddish or yellowish brown colour, with oc- casional patches of blue. It is of aloose texture, and contains septaria, casts of shells, selenite, and decomposing masses of sulphuret of iron. In the tunnel, about 60 feet below the most elevated part of the surface, the clay assumes .a dark bluish brown colour, and is much more compact, although here and there mixed with sand. ‘The greater part of the organic re- mains are procured from the depth of from 30 to 60 feet, and very few have been seen in the septaria. A few days since I observed at the top of Park-street, Camden Town, where the men were working at the depth of 10 or 12 feet, a layer of masses of septaria horizontally disposed ; this is of common occurrence, and the septaria are sometimes of a very large * Read before the Camden Literary and Scientific Institution, April 26, 1836, and communicated by the Council of that Institution, Mr. Wetherell on the Fossils of the London Clay. 463 size. The fossil copal*, or Highgate resin, so abundant at the Highgate Archway, occurs here but rarely. Fossil fruits analogous to those of Sheppey, crabs, lobsters, sharks’ teeth, scales and vertebree of fish, and the remains of a Trionyx, or marine turtle, have been found. If three divisions of the for- mation were made, I should consider the foilowing fossils as characteristic of each division, viz. Upper, Murex coronatus, ‘ Modiola elegans, Cardium nitens and Pectunculus decussatus, as atthe Highgate Archway. Middle, Pholadomya margari- tacea, Cardium semigranulatum, Nautilus regalis, Nautilus centralis, and Terebratula striatula, in the Regent’s Park. Lower, Arinus angulatus, Pentacrinites subbasaltiformist, as found at Islington and in the cliffs between Herne Bay and Whitstable, which are capped with diluvium resting on the London clay. In enumerating the characteristic shells of each division, I have principally selected those which are most abundant in it, and which are either very rare, or not found at all in the other divisions. For example, the Naw- tilus centralis, Nautilus regalis, and Cardium semigranulatum are only found in the middle division. The Axinus angulatus is very common in the lower, exceedingly rare in the middle, and does not occur in the upper division. And lastly, the Pectunculus decussatus and Cardium nitens abound in the upper, and are very scarce in the middle. In making a collection of fossil shells I have endeavoured to procure them at several periods of growth: this is the more desirable, since it is well known that many shells vary so much at different stages of growth, as to appear to be of several species, when they in reality be- long only to one. That there are considerable difficulties in the way of accomplishing this object I admit, but the result whenever it can be done, is most satisfactory. The following is a classed list, including all those (railroad) shells figures of which will be found in the first six volumes of Sowerby’s Mineral Conchology. Several of the localities are also taken from the same work. Among the unfigured shells are the following genera: Phasianella, Tornatella, Eulima, Cerithium, Pleurotoma, Pyrula, Voluta}, &c. Abbreviations of the Names of Places. HA. Highgate Archway. F. Finchley. uw. Well at * Phillips’s Elementary Introduction to Mineralogy, last edition, 1823, 0. 0/0» + Miller’s Natural History of Crinoidea, p. 140. t Note by Mr. J. De Carle Sowerby.—One species of Voluta naerly re- sembles Voluta Lamberti, differing from it however in having a longer spire and in being more oval. 1 propose to name it Voluta Wetherelliz, as a just tribute to the author of this paper. 4.64 Mr. Wetherell on some of the Fossils Lower Heath, Hampstead. uu. Hornsey. su. Sheppey. sou. Southend. sr. Brentford. pr. Richmond. Boe. Bog- nor rocks. AB. Alum Bay, Isle of Wight. BB. Bog- well Bay, Isle of ‘Thanet. FOL. Folkestone. Be. Barton Cliff. cut. Well at Colney Hatch-lane, near Muswell Hill. weH. White Conduit House Tunnel, Islington. vr. Vauxhall-road. HB. Cliff between Herne Bay and Whitstable. BH. Brackenhurst, Hampshire. cx. Child’s Hill. rp. Regent’s Park. su. Sussex. up. Hyde Park. gp. St. James’s Park. stu. Stubbington, Hampshire. Hor. Hordwell. rr. France. Ham. Hamsey. uworn. Horn- ingsham. pv. Dax. Gr. Grignon. Ls. Site of the Old Post Office, Lombard-street, City. amp. Hampshire. BBs. Bracklesham Bay, Sussex. Lyn. Lyndhurst. Nor. Nor- mandy. The following abbreviations are introduced in order to point out those shells which are rare and those which are common at the railroad. nr. Rare. vr. Veryrare. c. Common. vc. Very common. CONCHIFERA. Order I. Dimyanrta. Rare or Vol.| Tab. Fig. Other Localities. Common, Teredo antinaute ........ 1 |102) 1,2,4-8] wa. F. HW. H. SH. Sov. vc. Pholadomya margaritacea* | 3 |297| 1,2,3 | Hw. BR.R. BUG. AB. BB. FOL. Cc Corbula globosa .........- 3 |209| 3 HA. c. PUCINA DAIS ase kistears tee ole 6 |557| 1 BC. HA. F. VR. Astarte rugata ........... | 4 | 316 HA. HW. CHL. SH. R. Axinus angulatus.......... 4/315 HW. H. WCH. VR. HB. vR. Venus incrassata .........- 21155} 1,2 HW. BH. VR. Cardium nitens® .......... 1114 HA. CH. F. HW. SH. VR. Cardium semigranulatum¢..| 2 | 144 BC. WCH. RP. SU. Cc. Isocardia sulcata .......... 3 | 295) 4 WCH. SH. VR. Pectunculus decussatus aceiste;| elie rae a HA. CH. F. HW. SH. BOG. VR. Nucula amygdaloides...... 6 | 554) 4 HW. SU. SOU. HP. JP. FOL, ve. * Nucula inflata ............ 6 1554} 2 HA. CH. F. HW. C. Modiola depressa.....-.... 1/8 HA. CH. F. HW. VR. Pinta ais”. scrice cee cm vos 4 |313/ 2 HA. BOG. HW. H. R. Order II. Monomyaria. Avicula media............ ie HA. F. HW. SH. c. Pecten corneus .......... 3 | 204 STU. VR. Ostrea dorsata ..... -..-| 9 | 489] 1,2 HOR. FR. R. Anomia lineata ....... se) O 4aeD BC. BOG. HA. HW. R. Order IIT. Bracuroropa. Terebratula striatulat ... | 6 | 536)| 3) 5 SOU. SH. HAM. HORN. D, HW. Cc. Lingula tenuis ..........| 1 |19 | 3 HA. CH. F, HW. BOG, R. of the London Clay. MOLLUSCA. Order I. Gasrrropopa. | Vol.) Tab, Fig. Other Localities. Bulla constricta .......... 5 | 464] 2 BC. Bulla attenuata .... ..... | 5 |464) 3 HA. SH. : Dao elas z : Natica glaucinoides® .... } 15 1479| 4 } H.A. CH. F. HW. CHL. H. SH. Vermetus bognoriensis® 6 | 596) 1-3 HA. HW. CHL, SH. BOG. Dentalium nitens ........ W/O | ele 2 HA. HW. Dentalium incrassatum ..... 1 | 79 | 3,4 HA. HW. R. Solarium patulum ........ inl HA. F. HW. CHL, H, F. Trochus extensus ........ 3.1278) 2,3 HA. SH. Fusus errans....... mpepeteuie: Mei) BC. HOR, STU. bifasciatus... 5.0. .- 3 | 228 HA. SH, —— tuberosus .......... 3 | 229! 1 HA, ——- interruptus ........ 3 | 304} BC. — trilineatus.......... 1 | 35 HA. BR. SH. , ? (| 2 | 187) 2 —— regularis ........ 1! 5 | 423] 1 } HA. SH. BC. — coniferus .......... 2 |187) 1 HA. —— porrectis .......... 3 | 274] 8,9 HA, HOR. Pyrula nexilis ........ : 4 | 331 HA. BC..GR. LS. F. HW. Greenwocdii ...... 3 | 498 HA. HAMP. SUEOMATAUEUS)« .\¢) s | 4 | 355 HP. WCH. Z1CZac Ade) ee Sl a HA. SH. NOTES. 465 Rare or Common * A specimen of Pholadomya margaritacea and also one of Nucula amy- gdaloides have been found in the gault at Folkestone by that indefatigable friend to science J.S. Bowerbank, Esq. I have much pleasure in stating that our knowledge of the organic remains of the London clay (particularly those of Sheppey) will ere long be most materially increased by the praise Third Series. Vol. 9. No. 56, Dec. 1836. 3K 466 Mr. Wetherell on some of the Fossils worthy exertions of that gentleman. The great pains he has taken in col- lecting and arranging specimens can only be duly appreciated by those who have undertaken a similar task ; and the splendid series of fossils in his col- lection, principally appertaining to the tertiary and secondary rocks, are well worthy the attention of the geologist. > Also found in the lias. See Sowerby’s Index to the first six volumes of the Mineral Conchology of Great Britain, page 242. © This shell is also figured by Brocchi, in his Conchologia Fossile sub- apennina, tom. ii. tavola xiii. fig. 14. He has given the name of Venus cypria, although he considers that it very nearly approaches the form of a Cardium. It is evident that the specimen in his possession did not exhibit the hinge. 4 Gault to London clay. See Sowerby’s Index to the first six volumes of the Min. Con., p. 245. e Also in the crag. See Sowerby’s Index, p. 246. f Mantell’s Geol. of S_E. of England, page 367. Hist. Suss., vol. iii. pl. 1. f.3. Geol. Suss., 272. g Mantell’s Geol. of S.E. of England, page 366. » Also found at Stubbington. Webster, Geol. Trans., first series, vol. ii. page 204, On the strata over the chalk in the S.E. part of England. * Webster, Geol. Trans., first series, vol. ii. page 204. In a list of the organic remains in the lower marine formation above the chalk in England, Cyprea Pediculus is marked as having been met with at Highgate and Stub- bington. Only onespecies has been found at Highgate ; it is therefore very probable that the one referred to is the same, although the specific name is different. Stubbington may therefore be considered an additional lo- cality for this beautiful shell. Fifty-five species are enumerated in the above list, besides which I have (from the railroad) forty species which have as yet not been figured as British shells, independently of a few, which are extremely minute, of the order Cephalopoda ( Fora- minifera), consisting of Spirolina, Orbulites, Nummulites, &c., making altogether above one hundred species. A part of the un- figured shells having also been found in digging a well at Lower Heath, Hampstead, plates of them, with descriptions, will be given in the Geological Transactions, to illustrate a paper read before the Geological Society on the 4th of June, 1834*; the remainder will appear in some of the early numbers of the continuation of Sowerby’s Mineral Conchology. I have several examples of the Nautilus regalis, which present a very singular marking. A number of serrated lines may be seen in the outer lamina of the shell, running across it, and gene- rally two or three parallel to each other. Although they pass some depth into the substance of the outer lamina, they do not, as far as I have hitherto observed, extend to the inner one. ‘The great zeal which Mr. J. DeC. Sowerby has always i evinced in the advancement of science has induced me to give ~ his name to a new species of Nautilus which ] have discovered at the railroad. This distinguished naturalist, on more than * Proceedings of the Geological Society of London, vol. ii. page 98. ka it i? Fe Hewred YY FPL of the London Clay. 467 one occasion, has most kindly and readily afforded me infor- mation on subjects connected with my scientific pursuits. In my cabinet are two Nautili, brought trem the Isle of Sheppey by J. S. Bowerbank, Esq., which appear to belong to the new species, but Mr. Sowerby, having examined them, considers that they are not sufficiently perfect to state that they do so with certainty. It was in the year 1833 that I first discovered the minute cephalopodous Mollusca in some masses of clay which Thad brought from a well on Hampstead Heath. ‘This led me toa further examination of the clay in other spots, when I again met with them in the clay and on the surface of some pieces of iron pyrites. Of one species I found several attached to the whorls of Vermetus bognoriensis, Another species has several spines projecting from different parts of the outer surface, which I have not seen in any of the Grignon shells. The President of the Geological Society, in his Anniversary Address *, mentions that Mr. Lonsdale, in arranging the col- lection of the Society, had found “that our common white chalk, especially the upper portion of it, taken from different parts of England (Portsmouth and Brighton among others), is full of minute Corals, Foraminifera, and valves of a small entomostracous animal, resembling the Cytherina of Lamarck. From a pound of chalk he has procured, in some cases, at least a thousand of these fossil bodies. They appear to the eye like white grains of chalk, but when examined by the lens, are seen to be fossils in a beautiful state of preservation.” Edward Charlesworth, Esq., F.G.S., in an able paper on the Crag Formation, published inthe London and Edinburgh Philo- sophical Magazine for August 1835, gives an extract of a letter received from Searles Wood, Esq., of Hasketon, near Wood- bridge, in which it is stated that his cabinet contains fifty species of minute cephalopodous Mollusca of the order Foraminifera, D’Orbigny, which belong to the lower division of the crag. Among the donations to the museum of the Geological Society in 1835, is the following: Spirolinites} in chalk flints from Stoke near Chichester, presented by the Marquis of Northampton, F.G.S. The shells of the most rare occurrence (at the railroad) are Phasianella, Tornatella, Cypraa oviformis, Cardium ni- tens, Pectunculus decussatus, and Conus concinnus. ‘The most abundant, are Rostellaria lucida, Fusus interruptus}, and Na- lica glaucinoides. * Address to the Geological Society, delivered at the Anniversary, on the 19th of February 1836, by Charles Lyell, Jun., Esq., President. Pro- ceedings of the Geological Society of London, p. 360. + Proceedings of the Geological Society of London, vol. ii, p. 341, ¢ A well-known Barton shell. 8K2 468 Mr. Wetherell on the Fossils of the London Clay. In the year 1829 I met with (on breaking some masses of septarium, which I had brought from Child’s Hill, north-west of Hampstead,) the remains of a species of Ophiura in a very good state of preservation; and as the remains of Ophiura had never before been noticed as occurring in the London clay, I considered the discovery of sufficient importance to make it the subject of a communication read before the Geo- logical Society on January the 9th, 1833*. I have since seen a fine specimen from Harwich, which is in the cabinet of Edward Charlesworth, Esq. ; there is likewise one in the col- lection of J. S. Bowerbank, Esq., recently obtained from the Isle of Sheppey. The following list may be useful, as it contains a few more of the organic remains (from the railroad): I have also added some other localities. Crustacea. Cancer Leachit. Highgate Archway and Isle of Sheppey. Astacus+. Do., Isle of Sheppey, and Hampstead well. Radiaria. Pentagonasta. Hampstead well and Isle of Sheppey. Pentacrinitest subbasaltiformis. Hampstead well, Mr.War- ner’s well at Hornsey, and the cliffs between Herne Bay, and Whitstable. Zoophyta. Turbinolia. Sheppey. Reptilia. Trionyx§. Sheppey and Harwich. In the above pages, I have as much as possible avoided technicalities, wishing to give a plain statement of those facts which have come more immediately under my own observa- tion; and as other collections have been made from this rich * Proceedings of the Geological Society of London, vol. i. p. 415. + Two species, one of which appears to be the same as Astacus cata- clysmi in the British Museum, the locality of which is not marked. t The London clay portion of the cliffs between Herne Bay and Whit- stable belongs to the lower division of the stratum. About three years since I brought away several dozen of stems of Pentacrinites, which are very common there. At the railroad the Pentacrinite is extremely rare. The remains I possess from there, consist of some stems, parts of the auxi- liary side arms, tentacula, and a few bones of the pelvis. § Asplendid fossil Turtle found in the Harwich cement-stone is in the British Museum. It is from the collection of Edward Charlesworth, Esq., and a very excellent and correct engraving of it has been made by Stan- didge and Lemon of Cornhill. Mr. Rainey’s Reply to Dr. Ritchie’s Remarks. 469 deposit, I trust more information in a short time wil! be laid before the members of the Camden Literary and Scientific Institution. Highgate, April 23, 1836. LXXXVII. Reply to Dr. Ritchie’s Remarks on Mr. Rainey’s Theory of Magnetic Reaction. By G. Rainey, Member of the Royal College of Surgeons.* D® RITCHIE, in his reply to my last letter, appears to have attached a meaning to my explanation totally dif- ferent to that which it was intended to convey. Dr. Ritchie asserts that I take for granted “ that a piece 4 of soft iron B, placed in the direction of one \ side of the horse-shoe magnet A, will haye a magnetic power represented by 0, induced in its remote extremity, while the power of the pole S still retains its inducing power.” As N I cannot suppose that Dr. Ritchie has so far ; intentionally mistaken my meaning as to at- bee tribute to me the adoption of a postulate at Pa variance with common sense, I must suppose B _ this mistake to have originated in some verbal obscurity, or want of perspicuity in my b phraseology. As I have failed so far in making my meaning intelligible, and being allowed the indulgence of a second trial, I will endeavour to be more explicit, as I am particularly anxious that nothing like technical disputation should prolong this controversy. Dr. Ritchie says “that S cannot induce a power on a piece of soft iron, without having its own power diminished by an equal quantity.” This is a fact which I am most ready to admit, and which I never doubted ; and accord- ing to this fact, when the contiguous end of B has received all the magnetism S is capable of inducing, the magnetism at this end will be represented by 4, which is equal to a in its inducing power, though of an opposite kind. When magnetism is induced in ferruginous matter by the contact of either pole of a permanent magnet, the remote ex- tremity instantly assumes a magnetic state, opposite in kind to the contiguous one, and consequently similar to the mag- netism of the inducing pole. Now, as the one magnetism always induces that of a dissimilar kind, the magnetism of the remote end of B may be considered to result immediately from the induction which has been produced upon the conti- * Communicated by the Author. 470 Mr. Rainey’s Reply to Dr. Ritchie’s Remarks guous one by the permanent magnet, and not from the per- Inanent magnet itself. As the magnetism, then, at one extremity of B may be considered as immediately resulting from the induction on the other, it is highly probable that the inducing power of both is equal. This appears evident from the following experi- ment. Apply a piece of soft iron to-either pole of magnet and ascertain the weight it will sustain; then apply another piece to the remote end of the former one, and it will be found to sustain nearly the same weight. This experiment will be influenced somewhat by the form and size of the pieces of iron, by the state of the surfaces in contact, and by any condition of the metal which could interfere with the free and equable distribution of magnetism throughout its substance. It is only when every obstacle to free induction vanishes that the magnetism of the keeper B will be correctly represented by a+. Now, admitting that under these circumstances (a + 6) is a correct expression for the magnetism of the keeper, when it is in contact with the S pole, the same expression would be correct if it were applied to the N pole; and as there is no known limit at which soft iron ceases to allow of further in- duction by an increase of the inducing power, we must admit that the magnetism of the armature when under the inducing influence of both poles, will be double that which it had when exposed to the action of one pole only, and consequently re- presented by 2(a + 6). This will account for the fact of the attraction of the keeper when in contact with both poles of a horse-shoe magnet, at the same time so very far exceeding that which it has for the two poles when applied separately. Dr. Ritchie asserts that it is impossible for the lifter by its reaction to increase the power of an electro-magnet, because the lifter, having obtained all its magnetism from the electro- magnet, cannot give back more than it has received. Now, the following experiment will prove beyond all doubt that the lifter can increase the power of the electro-magnet; con- sequently by the converse of Dr. Ritchie’s reasoning it may be inferred that the keeper can be made to possess a higher magnetic state than the electro-magnet to which it applied, which is perfectly consistent with the above reasoning. Heat a common horse-shoe magnet to whiteness, for the pur- pose of totally destroying its magnetism and rendering it more easy of induction. Pass a piece of insulated copper wire around it, in the manner of an ordinary electro-magnet, and let this magnet be exposed to the action of a galvanic battery, when it will be found to have acquired a small: quantity of magnetism. Keep up the galvanic action until the magnet on the Theory of Magnetic Reaction. 471 ceases to allow of any further induction from this source. Now apply a very hard stee! lifter to both poles, keeping up the same galvanic current, and the magnet will be found to have gained a considerable increase of permanent magnetism. After the magnet thus operated upon ceases to indicate any further increase of its magnetism, apply a lifter composed of very soft iron of precisely the same dimensions as the former one, the galvanic action being continued, and the magnet will be found to have acquired a still higher charge of permanent magnetism. Now as the induction from the galvanic current was the same in each stage of this experiment, and the effect produced varied according as the condition of the keeper was more or less favourable for induction, the increase of perma- nent magnetism would appear to depend upon the reaction of the keeper, which, by the converse of Dr. Ritchie’s reasoning, must then possess a higher state of magnetism than the magnet to which it is applied. The experiment proposed by Dr. Ritchie would certainly set this matter at rest provided it answered ; but in case it does not, it will not in the least invalidate these facts concerning magnetic reaction: less conclusive evidence gained from ex- periment and reasoning is not to be totally abandoned because perfectly decisive experiments are unattainable. I believe the experiment proposed by Dr. Ritchie will not succeed, in con- sequence of the keeper, under the circumstances he has named not possessing an inducing power sufficient to overcome the re- sistance which steel furnishes to magnetic induction. It is well known that magnetism having once been induced in a piece of steel and partially destroyed by heat or the action ofsimilar poles of another magnet, may be in some measure restored by there- action of the keeper. This is probably owing to the particles of iron having acquired a tendency to resume their former state when the exciting cause is applied. ‘This would be an instance of induction just as much as if the steel had never been magnetized, for the addition of magnetism is just as necessary to restore that which has been lost as to impart it in the first instance. Dr. Ritchie says that if the explanation which I have given be admitted, it will completely overthrow the Newtonian Jaw of the perfect equality of action and reac- tion. I had always considered this law as applicable only to mechanical forces, and not extending in the least to these physical pheenomena, the acting cause of which is altogether unknown. Suppose a number of pieces of steel properly tem- pered, and for convenience made into the form of the common horse-shoe magnet, and one of these magnetized to saturation; now by this one let all the others be magnetized, and after- 472 The Rev. Professor Callan on a new Galvanic Battery. wards let them be put together, and the process of magnetizing be performed repeatedly upon each by the rest; and it will be found that each magnet possesses nearly, if not quite as much magnetismas the one employed in the first instance, that is, as the prime motor itself. This fact can scarcely be doubted, although it is at variance with the Newtonian law of the per- fect equality of action and reaction as applied to mechanical forces, as no force can be supposed capable of generating under the same circumstances a force greater than itself. Again, suppose we consider caloric as a moving force ; what relation is there between that which is required to ignite a quantity of gunpowder and the caloric developed by its com- bustion? Several similar instances might be adduced of the inapplicability of the Newtonian law to the explanation of obscure physical facts. LXXXVIII. On a new Galvanic Battery. By the Rev. N.J.Catxan, Professor of Natural Philosophy in the College of Maynooth.* Tue following paper describes a new galvanic battery, con- sisting of 20 zinc and as many double copper plates, the whole of which may, by substituting one mercury trough for another, be made to act as a single pair of plates, or as 2, 3, 4, 5, 6, 10, or 20 voltaic circles; and which is capable of producing, by the aid of an electro-magnet, a voltaic current equal in intensity to that ofa battery con- taining 1000 pairs of zine and copper plates. lint my directions, and ona plan suggested by me, a very large galvanic battery has been lately constructed for the College of Maynooth. This battery consists of 20 zine plates, each two feet long and two feet broad, and of as many copper cells, each sufficiently large to contain one of the zine plates. To each zinc plate is soldered a copper wire about half an inch thick and six inches long. The wire projects from the platefin a direction nearly parallel to the sides, and nearly per- pendicular to the edge of the plate, which is vertical when the plate is in its copper cell. Attwo inches from its extremity the wire is bent so as to form nearly a right angle at the bend, and so that these two inches are parallel to the vertical edge of the plate. A wire of the same thickness, and about two inches shorter, is soldered to each of the copper cells: it is bent in the same way as the wires belonging to the zinc plates. * Communicated by the Author, Fhe Rev. N. J. Callan on a new Galvanic Battery. 473 Figures 1 and 2 representa zinc plate and a Fig. 1. copper cell along with the wires soldered to them. ‘The 20 copper cells are put into a wooden box about 34 feet long, 2 feet 2 inches deep, and nearly 3 feet wide, and are separated from each other by partitions of wood. ‘The 20 zinc plates are let down into the copper cells, and are lifted up, at Fig. 2. pleasure, by means of a windlass. To pre- vent the contact of the zinc plates with the copper cells, each zinc plate is covered with a woven net of hemp. When the 20 copper cells are in the wooden box, and the 20 zinc plates in the copper cells, the wires soldered to the copper cells project about ? of an inch from one of the sides of the box, and their extremities descend nearly 2 inches below the upper edge of the same side: but the wires soldered to the zinc plates project nearly 2 inches from the same side of the box, and their extremities descend as low as the extremities of the wires belonging to the copper cells, Thus, if A B (fig. 3.) in the exterior surface of one of Fig. 3. pei e meters Skew ite CAP MS 2 Oe a the sides of the box be parallel to the upper edge of the same side, and nearly 2 inches below it, then the row of points ¢ c’ will represent the extremities of the wires belonging to the copper cells, and the row of points z z' will represent the ex- tremities of the wires soldered to the zinc plates. The acid solution is poured into the copper cells, which are water-tight, and is let out, without lifting the cells, by means of a cock at the bottom of each cell. The cells are barely wide enough to allow the free ascent and descent of the zinc plates. About 30 gallons of fluid are required to charge the whole battery. Both sides of each zinc plate are exposed to the action of the acid mixture, and are within about a quarter of an inch of an equal and parallel surface of copper. Hence the acting surface in each plate is 8 square feet, and the acting surface of zinc as well as of copper in the whole battery is 160 square feet. By eight mercury troughs, metallic communications may be formed between the 20 zinc plates and the copper cells, so as to make the whole act asa single pair of plates, each containing 160 square feet of surface; or as 2 voltaic circles, in which Third Series. Vol. 9. No. 56. Dec. 1836. 3L 474 The Rev. N. J. Callan on a new Galvanic Baitery. the zine of each circle would contain 80 square feet; or as 3 circles, two of which would contain 56 square feet of zinc, and the third of which would contain 48 square feet ; or as 4 circles, in each of which there would be 40 square feet of zinc; or as 5, in each of which there would be 32 square feet of zinc ; or as 6 circles, four of which would each contain 24 square feet, and two of which would each contain 32 square feet of zinc ; or as IC circles, in each of which there would be 16 square feet of zinc; or as 20 circles, each of which would contain 8 square feet of zinc. The mercury troughs are made by cutting holes for con- taining mercury in a piece of wood 3} feet long, 35 inches broad, and 2 inches thick. The mercury trough by which all the zinc and copper plates are made to act as a single pair, contains two parallel grooves, each nearly 3} feet long, ¢ of an inch wide, and an inch deep. One of the grooves receives all the wires of the zinc plates, and the other receives all the wires of the copper cells. Hence when mercury is poured into the two grooves, all the zinc plates are in metallic commu- nication with each other, and act as one plate; and all the cop- pers likewise act as one copper plate. This trough is repre- sented in fig. 4.; the letter z shows the groove for the wires of Fig. 4. & [ a ee ee ee Se eT Le Se a ee Ct eS c the zinc plates, and ¢ the groove for the wires of the copper cells. In the second mercury trough there are four grooves, each of which receives 10 wires. There is acommunication be- tween one of the grooves containing the wires of ten copper cells, and that which receives the wires of the zinc plates im- mersed in the remaining 10 cells. Fig. 5. represents this Fig. 5. & % Se Pa = =a rsa | gen Mods DUNE OIE ey Se ( Cc trough. The third trough contains 6 grooves ; the fourth, 8; the fifth, 10; the sixth, 12; and the seventh and eighth each contain 20. Except the trough by which the battery is made to act as 20 voltaic circles, the rest are made like the trough represented in fig. 5. When the battery acts as 20 cir- cles, the wire of each zine plate, and the wire of the next The Rev. N. J. Callan on a new Galvanic Battery. 475 copper cell, are in the same mercury hole. Fig. 6. represents Fig. 6. ® 232 2 2&8 BS 2% BS SB BEEK BS WOR CLC, OA fy COG 70ee. Ver £0 V6 NC. Cla. € Ht the upper surface of the trough by which all the zine and copper plates are made to act as 20 circles. From the preceding description of our battery, it is evident that the whole 20 zinc plates and copper cells may, by substi- tuting one mercury trough for another, be made to act asasingle pair, or as 2, 3, 4, 5, 6, 10, or 20 voltaic circles, and thus be made to supply the place of the calorimotor and of the battery hitherto used for electro-magnetic experiments. So enormous is the quantity of electricity circulated by this battery when all the zinc and copper plates act as a single circle, that, on one occasion, after having acted without interruption tor more than au hour, it rendered powerfully magnetic an elec- tro-magnet on which were coiled .39 thick. copper wires, each about 35 feet long, while the mercury in which the wires of the zinc plates were immersed, was connected by 6 copper wires, each ! ofan inch thick and about 6 incheslong,with the mercur in communication with the wires of the copper cells. On the fifth day it was tried: after having been in action without in- terruption for more than two hours, this battery melted very rapidly platina wire ;\;th ofan inch thick, and deflagrated in a most brilliant manner copper and iron wire about ;4;th of an inch thick. By this battery, with the aid of an electro-magnet, a current of electricity may be produced which will equal in intensity that of a battery containing 1000 voltaic circles. It is well known that when the connexion between the helix of an elec- tro-magnet and the voltaic battery is broken, a current of elec- tricity is, at the moment of breaking the connexion, made to flow through the helix; and that when the helix is long, that cur- rent is capable of giving a shock to any person who holds in each hand a copper cylinder in conducting communication with the ends of the helix. By experiments on the best means of obtaining the shock from the electro-magnet, I have found that the shock increases, within certain limits, with the length and thinness of the bar of soft iron, and withthe length of the heliacal coil, as far perhaps as 200 feet, and in proportion, or nearly in proportion, to the number of plates in the voltaic battery from which the current of electricity is passed through the helix. The shock does not increase in proportion to the number 3L2 476 The Rev. N. J. Callan.on a new Galvanic Battery. of plates unless they are large. The electro-magnet whick I first used was a straight bar of soft iron, about 2 feet long, and aninch thick. On this bar were coiled two copper wires, each about 200 feet long. The voltaic battery consisted of 14 pairs of zinc and of as many double copper plates: each plate was about 7 inches square. The end of the first coil and the be- ginning of the second were immersed into the same cup of mer- cury, the voltaic current was passed through the first coil only, and the shock was taken by making a communication with the beginning of the first coiland with theend of the second. When the current of electricity was passed through the helix from one pair of plates, the shock received on breaking contact with the battery was equal to that ofa battery containing 20 pairs of plates. When two pairs of plates were used, the shock ap- peared to be doubled ; with three voltaic circles, it appeared to be trebled; and with every increase in the number of voltaic circles, there appeared to be a proportional increase of the shock. With the 14 pairs of plates the shock was so strong that a person who took it, from an electro-magnet on which there werefour coils of wire, felt the effects of it for several days. With a battery of 4-inch plates the shock increased with the number of plates, but not so rapidly as when large plates were used. I am inclined to think that with a battery of 4-inch plates, the shock increases but little when the number of plates exceeds a hundred. I could not induce any one to take the shock from the electro-magnet when a greater number than 16 of our large plates were used. With 16 of them the shock was exceedingly strong, although the acid mixture employed in charging the battery was very weak ; and, from experience, I know that the electro-magnetic effects of a battery depend very much on the strength of the charge. From all the experiments which I have made on the mag- neto-electric shock, I think I may fairly conclude, that, if 2000 feet of wire were coiled on a bar of soft iron 6 feet long and an inch thick, a shock might be obtained with the aid of a single pair of plates, which would equal that of a battery ot 100 voltaic circles. Hence, since the shock increases in pro- portion to, or, at least, very rapidly with the number of plates, when they are large, the shock given by such an electro-magnet magnetized by our battery of 20 pairs of plates, should nearly equal, or perhaps exceed that of a battery of 1000 voltaic cir- cles. Hence, by our battery of 20 pairs of plates, an electric current of the highest intensity may be produced. This bat- tery then supplies the place of all the various kinds of galvanie batteries. The shock given by the electro-magnet may be obtained The Rev. N. J. Callan on a new Galvanic Battery. 477 as often as the connexion of the helix with the battery is bro- ken. Now I have devised a small instrument by which com- munication with the battery may be broken and renewed 3000 or 4000 times in a minute. Thus 3000 or 4000 shocks may be received, and 3000 or 4000 electric currents of the highest intensity may, in the space of one minute, be passed through water, charcoal, metallic wires, or any other body. It should be remembered that the voltaic current from the battery should not be passed through more than 200 feet of the heliacal coil, and that the shock should be taken from the whole length of the helix. When a voltaic current passes through a very long wire from a single pair of plates, the wire will give a shock at the moment of breaking contact with the battery. I have found that this as well as the shock from the electro-magnet in- creases with the number of plates. I have made a great variety of experiments on electro- magnets. My object in these experiments was to ascertain four things: first, on what the quantity of attraction depends ; secondly, on what the distance at which that attraction is exerted depends; thirdly, on what the shock depends; and fourthly, whether by a voltaic current from a large battery, a permanent magnet could be made, which would induce on soft iron magnetism equal to that which is given to an electro- magnet by a battery containing 20 large plates, or 500 four- inch plates. In these experiments I employed three different voltaic batteries, and electro-magnets of various forms. I used the large battery already described; a small battery of 14 pairs of plates, in which each zine plate was seven inches square; and a Wollaston battery, containing 280 pairs of four- inch plates. Some of my electro-magnets were straight, and others of the horse-shoe form, and one was a square: the iron bars varied in length from 20 inches to six feet, and in thick- ness from two inches to halfan inch. On one of these were coiled 39 copper wires, on another four, on a third three, and on others there was only one wire. From the results of these experiments, I have deduced the following conclusions: First, that the quantity of attraction increases with the length of the bar of soft iron, at least as far as six feet, and withthethinness till it becomes about an inch; and that it increases nearly in proportion to the number of plates (when they are large) in the battery by which the electro- magnet is magnetized. When the plates are only four inches square the attraction increases, but slowly when the number exceeds 100. Secondly, that the distance at which attraction is exerted, increases also with the length and thickness of the 478 The Rev. N. J. Callan on a new Galvanic Battery. iron bar, and with the number of plates when they are large} but with small plates the increase is very gradual when their number exceeds a hundred. With twenty of our large plates, an iron bar, nearly 34 lbs. weight, was attracted to a horse-shoe electro-maguet through the distance of an inch, and with ten plates the same bar was attracted to the same magnet, only through the distance of about half an inch. Again, with the twenty plates, the attraction of the same magnet for a sewing- needle was sensible at the distance of 15 inches, and with ten plates the attraction was sensible at the distance of 10 inches. Thirdly, that the shock from the electro-magnet increases within certain limits with the length and thinness of the iron bar, and nearly in proportion to the number of plates when they are large. When the voltaic current was sent from a battery of 280 four-inch plates, through the heliacal wire coiled round a steel bar about 20 inches long and an inch thick, the steel became almost as strongly magnetic as if it were iron; and when the connexion with the battery was broken, the steel did not retain more than about ;4, of its magnetism. In a paper published in the last (August) number of the Philosophical Magazine, Dr. Ritchie says that the use of the electro-magnet in the apparatus for continued rotation was long since abandoned, because it was incapable of inducin magnetism in an iron bar at a distance. Now he will find that, if instead of a single copper and zinc plate, a battery of 20pairs of large plates, or of 200 small ones be used, the electro- magnet will have a greater power of inducing magnetism at a distance than any permanent magnet. The advantages of the battery I have described are, first, that it supplies the place of all the various kinds of voltaic batteries, of the battery for producing a ldrge quantity of electricity of low intensity, of the battery for exciting a large quantity of electricity of the intensity necessary for the rapid fusion and deflagration of metallic wires, and of the battery for producing an electric current of high intensity ; and secondly, that it enables a person to compare the power of the very same zinc and copper plates acting as a single pair, with their power when they act as 2, 3, 4, 5, 6, 10, or 20 voltaic circles, Nicuoas Cayan. Maynooth College, August 23, 1836. C. #79yq LXXXIX. Cbservations on certain Liquids obtained from Caoutchouc by Distillation. By Joun Darton, D.C.L., F.R.S., Sc.* Manchester, November 10, 1836. D:: GREGORY having published in the last number of the Philosophical Magazine (p. 321.) some interesting experi- ments and observations on the liquid obtained by the distilla- tion of caoutchouc, | have thought it would be acceptable to that gentleman, as well as to the public, to be made acquainted with the results I obtained from the same subject about two years and a half since, more especially as my experiments chiefly tend to establish additional properties to those de- duced in Dr. Gregory’s essay. For this purpose I send the Editors a copy of my paper read before the Literary and Phi- losophical Society of Manchester, on the 17th of October, 1834, which has not been published. JI think it is obvious from what follows that most or all the varieties of vegetable combustible products of the oily character must be constituted of central atoms of carbon, oxygen, or carbonic oxide, along with a number of atoms of binolefiant gas, placed alternately around the central atom; and that the repeated distillation of them, at first with a greater and then with a less heat, gra- dually attenuates the compound atom, till at last it becomes one or two atoms of binolefiant gas slightly adhering to the less volatile parts of the oil, so that the gas, when not under suf- ficient restraint, expands into the atmosphere at the ordinary temperature. Observations, §c. Read October \7, 1834. The article caoutchoue is too generally known to require a particular description ; it may suffice to observe that it is obtained from the milky juice of certain trees in South Ame- rica, which juice is procured by incisions made in the bark of the trees. When the watery part of the juice, which consti- tutes more than half its weight, is evaporated, there remains a solid elastic substance, which is the caoutchouc. ‘The proper- ties and peculiarities of this singular substance have been mostly described in books of chemistry and other works, and therefore need not here be enumerated. Some new charac- teristics, however, seem lately to have been discovered by sub- jecting the article to repeated distillation, and it is upon those that we are about to make a few observations. Most if not all vegetable products are liable to be decom- posed by heat. They are mostly resolved into solid, liquid, and elastic substances, according, in some degree, to the temperature. ‘The instance of the destructive Sistillation of * Communicated by the Author, 480 Dr. Dalton’s Observalions on certain Liquids wood may be taken for an example: by this process we find a solid body resolved into another solid body, charcoal; into various liquids, as water, acetic acid, and pyroxylic spirit ; into gases, as carbonic acid, carburetted hydrogen, carbonic oxide, and hydrogen. Caoutchouc is highly combustible: when we burn a slip of it, the flame is white and brilliant ; and if we extinguish the flame suddenly, the heated extremity is soft and nearly fluid ; hence it would appear that this substance is reducible to a fluid before decomposition, and in that state might probably be distilled like the fat oils; but, like these, the products of the first, second, and future distillations would be successively more volatile, and require a lower temperature for their distillation. This it seems has been found to be the fact. Having been favoured by an unknown friend with four phials of liquids obtained from caoutchouc by successive distillations (as I apprehend), 1 found . the !st, adeep-coloured liquid, marked sp. gr °86; 2nd, a slightly coloured liquid, marked... :837; 3rd, a colourless liquid, marked ............ °7523 4th, a colourless liquid, marked ............ *680; all of which specific gravities I found very nearly correct. The last, I believe, is lighter than any other known liquid, ex- cept perhaps the one mentioned by Dr. Faraday,—see Phil. Trans. 1825, page 452. The Ist liquid I did not find the boiling-point of, but it is higher than any of the following: the 2nd boils at about 290° or 300°; 3rd 140°; 4th 107° or 108°. By letting a small portion of the 4th liquor through the mercury in a barometer tube, | find the force of its vapour in vacuo is very nearly the same as that of sulphuric ether, The other three liquors I did not expose in the same way, because it is obvious, from their boiling-points, that their elasticities in vacuo must be much inferior to that of the 4th. In order to form some estimate of the relative evaporation of the four liquids, I poured out small portions of the several liquids into glass cups, and dipped the bulb of a thermometer into the liquids, withdrawing it immediately to notice the re- duction of temperature by the evaporation. The thermometer being at the temperature of the room, 69°, it was cooled 15° by four or five successive dips into the liquor No. 4, 8° byvdipsianto;. 0.4. pyc ptinaeie sae. due 6i4 eet ee 13°) by-dipsinto, 2h.’ o> by osetia), ... cielo © Dy dips Wt scion ton | fas yectig ies alot os ON bo obtained fiom Cuoutchouc by Distillation. 48] By this we learn that the evaporation from No. 4 is exceed- ingly more than that from any of the others. The most remarkable circumstance relating to this evapo- ration from liquor No. 4 remains to be noticed: it is one that distinguishes it from the vapour of every other liquid that I have yet examined. The vapours from zther, alcohol, sul- phuret of carbon, &c., are rapidly absorbed by water, in the same manner as are muriatic acid and ammoniacal gases ; but the vapour from caoutchouc liquor highly rectified as No. 4, may be passed through water repeatedly without any sensible diminution or alteration of its quantity; at least the action is not more than on olefiant gas. The way to charge a quantity of air with vapour of any kind is to fill a phial with mercury, let in the proposed air till the phial is half full, then inverting it carefully, drop in a little of the liquid to be eva- porated, and immediately after again invert the phial over mercury inthe trough. The vapour then expands the air, and in a short time the maximum of expansion is produced. The mixture of air and vapour may then be used for any pur- pose over mercury. In the case of zether, however, a mercu- rial apparatus is not absolutely necessary; in a narrow tube zether may be turned up through water, and, if sufficient to form a thin stratum over the surface of the water in the tube, the ether vapour will rise into the air, and be defended from the water by the stratum of the liquid : in this way the mixture of air and vapour may be confined in repose for a month. In regard to the vapour from caoutchouc liquor No. 4, no such precaution is necessary. I take a graduated jar of 4 or 5 inches diameter; and having filled it with water, I let in 60 cubic inches of air, and turn the cock so as to confine it. I then put 20 or 30 water grain measures of the liquor into a tube and turn it into the water in the jar, through which it ascends to the surface and instantly spreads over it a thin film of an oily appearance. This film by degrees almost disap- pears ; at the same time the air gradually expands, and in about twenty minutes acquires its full expansion, becoming about 90 inches in a temperature between 60° and 70°. It will remain for days in this state, and there will be no change of volume unless there be a change of pressure or temperature of the atmosphere. This permanency of the vapour over the water affords an admirable facility for finding its specific gravity. Let 60 cu- bic inches of common air be expanded by vapour, suppose to 90 ; then, exhausting a flask and letting in a given number of inches of the mixture and weighing it, we shall have data to find the weight of the vapour, knowing previously that of Third Series. Vol. 9. No. 57. Suppl. Dec. 1836. 3M 482 Dr. Dalton’s Observations on certain Liquids common air. By two careful trials, I found by the above process the specific gravity of the vapour from the highest rectified caoutchouc liquor to be 2:07, common air being 1, and no allowance being made for aqueous vapour in a tempe- rature between 60° and 70°. By another experiment the spe- cific gravity of the vapour came out nearly 2. Another advantage is possessed by this vapour which others have not, namely, that when a given weight or measure of the liquor is passed through water, we are enabled to ascertain how much of it is actually converted into vapour. Thus, to 60 cubic inches of common air I added 25 measures of the liquor, "680 specific gravity : : in 4 minutes the air and vapour became 70 inches i —_—_—_—_———._ 76 — Oy Ga a oe and then remained stationary. Now, by calculating the weight of the 20 inches of vapour, and comparing it with the weight of the 25 measures of liquor, we find the ratio nearly as 3 to 4; so that only three fourths of this highly rectified liquor is vaporized in such circumstances, and the rest forms a delicate and partial smearing of oil over the surface of the water. This shows that a higher degree of rectification of the liquor is attainable. These four liquors, as might be expected, are all very com- bustible; a lighted taper presented to them ignites them in- stantly. They all burn with a white flame and great smoke. No. 4 leaves no residue; the others leave traces of carbon and moisture. The smallest electric spark lights Nos. 4 and 3. The vapour also is highly inflammable, and when mixed with oxygen gas may be exploded in Volta’s eudiometer. A mixture containing 1 measure of vapour requires 6 of oxygen, and produces 4 measures of carbonic acid; it would appear therefore to be constituted of 2 atoms of olefiant gas combined, and possessing the space of 1 atom of said gas nearly. Chlorine gas acts upon the vapour much the same as on olefiant. In one instance they seemed to combine in equal volumes, but in another more chlorine was taken up. I did not pursue this inquiry. Chloride of lime solution seems to have no effect upon the vapour. Though the vapour is not absorbed by water in an eminent degree, yet I find that water takes up one eighth of its volume of the vapour, which is the same proportion as olefiant gas and phosphuretted hydrogen are absorbed. It may be expelled obtained from Caoutchouc by Distillation. 483 again by another gas, but not in the full proportion, as would seem from one or two trials. It may be remembered that I read an essay on oil gas be- fore the Society in 1820, which, with some additions, was pub- lished in the fourth volume (new series) of the Society’s Me- moirs, 1824. In that essay it was made to appear that the por- tion of gas usually found both in oil and coal gas, denominated olefiant gas on account of its combination with chlorine, was not the same as the gas from alcohol by sulphuric acid. The former is much more dense and requires more oxygen to burn it than the latter. For want of a more definite term I called it superolefiant. It was shown to be more absorbable by water than the other ingredients of oil gas (page 80); and it was conjectured (page 81) that the new gas might consist of a gas having two atoms of olefiant in one, or united, and possessing a greater specific gravity than the common olefiant. I have now no doubt that my superolefiant is the same as the vapour we have been considering. ‘They are both obtained from olea- ginous substances and from coal by heat; .they agree in their action on chlorine, and in their absorbability by water, and, for aught that appears, in their specific gravity and in their products by combustion. In 1825 Dr. Faraday published an essay in the Phil. Trans. of the Royal Society, in which he noticed some new products obtained during the decomposition of oil by heat, one of which he calls ‘a new carburet of hydrogen.” ‘This appears to have every characteristic of the vapour we have been describing. See p. 452. The fat oils and the resinous body caoutchouc are composed chiefly of carbon and hydrogen ; indeed, we may say of olefiant gas, or rather perhaps binolefant gas, for those gases have their elements nearly inthe same proportion as the oils and resins. It is a remarkable characteristic of these last bodies that they can sustain a high heat without volatilization in their ordinary state ; but if subject to the temperature necessary for distillation, and this distillation be repeated, they become more and more volatile, till at length a liquid is obtained, the compo- nent atoms of which are a combination of 2 atoms of olefiant gas. May it not be presumed then that the original constitutions of such combustible bodies are charcoal or water, holding in combination numerous atoms of binolefiant gas, and that these combinations become less numerous as they are more loosened by heat and repeated distillations ? 3 M2 [ 484. ] XC. On Voltaic Electricity, and on the effects of a Battery charged with Sulphate of Copper. By Mr. W. DEA RueE*. | HE greatest effect being always produced in those voltaic arrangements where the chemical agent exerted an ac- tion on only one of the metals constituting the battery, it oc- curred to me to use a saturated and perfectly neutral solution of the electro-negative metal, provided the other was capable of effecting its decomposition. I therefore tried the effect ofa sa- turated solution of sulphate of coppert in an elementary voltaic battery of the ordinary construction. The zinc plate was four inches by two, the copper completely surrounding it: with this I was enabled to produce ignition of half an inch of platina wire one thirtieth of an inch in diameter, and continue it as long as the zinc plate lasted, which, being very thin, was dis- solved in a couple of hours. The effects of this battery were considerably greater than those of one made of platina and zinc of the same dimensions, this being immersed in diluted nitric acid. I afterwards constructed a battery with three four-inch zine plates connected together; these were immersed in a copper trough with two partitions, so that the zinc should be opposed on both its surfaces to a plate of copper: with this battery one inch of fine iron wire was kept ignited for four hours. The zinc plate is always partially covered with a coating of copper, which, however, is NOY DETRIMENTAL (0 the power of the battery : the copper plate is also covered with a coating of metallic copper, which is continually being deposited; and so perfect is the sheet of copper thus formed, that, on being stripped off, it has the polish and even a counterpart of every scratch of the plate on which it is deposited. Besides this, the voltaic influence decomposes the water; the oxygen, uniting with a portion of the copper and hydrogen, being set at liberty. ‘This may be readily shown by soldering at one end a piece of copper * Communicated by the Author. + Daniell uses sulphate of copper, but not as the exciting agent. Professor Daniell’s object was to cbtain a voltaic combination constant in its effects while the connexion is completed, and totally inactive when the circuit is interrupted. Sulphate of copper, used as an exciting agent, he found unsuited for this purpose, and therefore relinquished this employ- ment of it in his battery. That it did not escape Prof. D.’s attention, the following passage from his paper on Voltaic Combinations, in the first part of the Phil. Trans. for 1836, page 117, will show: “Upon adding sulphate of copper, in any considerable quantity, to the liquid in the cells, notwithstanding the amalgamation of the zinc, there was local action enough upon that metal to disengage hydrogen, which, in however small a quan- tity, was sufficient to commence the precipitation of the copper upon it. Single circles were thus immediately formed by the two metals, and local action increased to such a degree as speedily to cover the zinc with reduced copper.” See also page 109 - Enir.] Mr. W. De la Rue on Voltaic Electricity. 485 and a piece of zinc, coiling the two to forma small calorimotor, which isto be put intoa glass jar filled witha solution of sulphate of copper, and inverted ina vessel of the same; metallic copper and its oxide will precipitate, and hydrogen gas fill the jar. Seeing the effects so continuous in a simple battery, I tried a Cruickshank’s, of one hundred pairs, each plate exposing to the action of the fluid a surface of twenty-five square inches. This was charged with a saturated cold solution of sulphate of copper, to each three gallons of which I added two ounce mea- sures of nitric acid, for the purpose of cleaning the plates and freeing them from oxide; for half an hour the action was so feeble that I was on the point of emptying the trough, but I soon after noticed that the effect was rapidly increasing ; I was then induced to proceed. The batteries attained their maxi- mum of power in three quarters of an hour after charging. Charcoal points were vividly and continuously ignited, the are passing through a space of three eighths of an inch; this experiment was beautifully varied by dipping the charcoal in nitrate of strontian, the arc then being of a crimson colour. Steel points of wire, a quarter of an inch thick, were then tried; the arc passed through an equal space; the steel ra- pidly fused, was deflagrated, and by the scintillations pro- duced a beautiful effect. Copper points treated in a like manner produced a green arc, and were rapidly destroyed. Brass produced a blueish white arc; and the more fusible metals, such as bismuth and tin, produced likewise an arc, but the metal was soon carried from one point to the other and established a perfect contact. A piece of platina wire, one eighth of an inch thick, was ra- pidly fused, by keeping it at a short distance from a disc of copper, so as to ailow the arc to pass from it to the disc. A heap of metallic leaves was burned with rapidity, Thick tin-foil was deflagrated. Very thick zinc-foil was rapidly consumed. A bunch of needles burned rapidly in mercury; the end of a file was defla- grated in the same manner. Extraordinary as was the power of deflagrating metals, the effect of igniting was comparatively small; not more than an inch of iron wire could be ignited, though, if only twelve pairs of Wollaston’s four-inch plates were used, charged with the same solution, two anda halfinches could be kept ignited for some time. _ The battery was then tried in decomposing common caustic potash, which it did with facility; the combustion of the po- tassium evolved, vividly igniting the thick platinum wire used for the negative pole. These experiments occupied about two 486 Ona Voltaic Battery charged wite Sulphate of Copper. hours. The charcoal points were then again tried; and if there were any alteration the power of the battery had in- creased. Batteries charged in this manner will continue in un- abated action for upwards of three hours ; in fact until there no longer remains any copper in the solution. It is worthy of notice, that after the batteries have been in action some time, a large portion of the sulphate of copper is expended, and re- placed by sulphate of zinc, yet the action continues the same. This naturally suggests using a saturated solution of any neu- tral salt, common salt for example, and adding merely as much of the solution of copper as will serve for the time required. It is not unlikely that the effect would be more continuous than with a solution of copper only. I intend trying this, as I am still pursuing my inquiries on this subject, the object of which is to simplify as much as possible the voltaic battery. At the Marylebone Institution, on Monday, September 12, when a lecture was delivered on this subject by Mr. Hemming, the President, the power used was the hundred pairs of Cruick- shank’s arrangement before alluded to, and one hundred and thirty-two pairs of Wollaston’s four-inch plates, making in all two hundred and thirty-two pairs. The batteries I charged before the commencement of the lecture, and they were not used till an hour afterwards; the effects were very striking. The arc from the charcoal points passed through a space of three quarters of an inch, and the effect continued unabated for as long a time as could be spared for this experiment; soda was rapidly decomposed, and the so- dium brilliantly deflagrated : all the other experiments before cited were repeated on a much grander scale. The lecture being concluded two hours and a quarter after charging the batteries, the charcoal points were again ignited to light up the spacious theatre, the gas having been extinguished. ‘The shock was very powerful, even when taken with the hands dry*. Fifty pairs of four-inch plates on Cruickshank’s plan suffice for all the above experiments, except the decomposition of the fixed alkalies. ‘ * [As similar experiments to those here detailed have been performed with batteries of no extraordinary dimensions, charged in the usual way, it would have been more satisfactory had tke author informed us of the size and number of the plates requisite to produce the same effects when sul- phate of copper was not employed. We refer our readers who are inter- ested in the philosophical investigation of this subject to an admirable Essay by Dr. Marianini of Venice, of which an abridgement willbe found in the Annales de Chimie et de Physique, vol. xxxiii.p. 113. In his investiga- tion of the various causes which influence the energy of the pile, he has been led to examine the effect of different liquid solutions, and gives a table of the relative advantages of forty-nine acids and salts, one part of each being dissolved in one hundred of distilled water. —En1r. } . M. Boussingault on the Constitution of Bitumens. 487 Water was decomposed with extraordinary rapidity by a bat- tery of this description, and also muriatic acid, the chlorine of which bleached asolutionof sulphate of indigo in a few seconds. Its effects on the animal system, as exhibited by Mr. Hem- ming to the audience, were almost terrific. A rabbit recently killed, an eel, and frogs were thrown into more violent mus- cular action than I had ever previously witnessed *. The tension of electricity seems to be greatly increased by this mode of charging the voltaic battery. Bunhill Row, Sept. 15, 1836. XCI. On the Constitution of Bitumens. By M. Boussincavtt. N BOUSSINGAULT remarks, that bitumens, so abundantly met e with on the surface of the earth, and the uses of which seem continually to increase, have hitherto been but slightly examined, so that, if we except the researches of M. de Saussure on the naphtha of Amiano, we are still nearly ignorant of the particular nature of these substances. It has always been admitted that the great combustibility of bitu- mens is owing to their being chiefly composed of carbon and hydrogen, and the water which some varieties afford by dry distillation favours the idea that they are not always free from oxygen. In this memoir the author shows that they do not owe their fluidity to naphtha. The bitumen of Bechelbronn, which M. Boussingault has principally stu- died, is viscid and of a dark brown colour. From its uses it has been called mineral fat, it being advantageously used instead of organic fatty substances to diminish the friction of machines, &c. Alcohol at 40° acts on bitumen, particularly when heated, and acquires a yel- low tint. Sulphuric zther readily dissolves it. Heated in a retort to 212° Fahr. nothing distils : this proves that it contains no naphtha. By distilling the bituminous sand with water, M. Boussingault has obtained a volatile oily principle, which he calls petrolene, consider- ing it to be the volatile principle of petroleum : it possesses the fol- lowing properties : Petrolene is of a pale yellow colour, of a slight taste, and possesses an odour resembling bitumen; at the temperature of 70° Fahr. its specific gravity is 0°891 ; at 18° Fahr. it does not lose its fluidity ; it stains paper like the essential oils, burns with much smoke, boils at 536° Fahr. ; alcohol dissolves a small quantity of it, but it is much more soluble in ether. It is composed of Carbon, .. 8875 Hydrogen, .. 11°5 so that it is a carburet of hydrogen isomeric with the essential oils of * (That a battery of two hundred and thirty-two pairs of four- and five- inch plates, or even of a hundred pairs, should violently convulse rabbits, eels and frogs, is by no means an extraordinary result. The really terrific experiments made by Dr. Ure on the murderer Clydesdale, at Glasgow, were performed with a voltaic battery consisting of 270 pairs of four-inch plates, charged with dilute nitro-sulphuric acid, —Eprr.] f From L’ Institut, Sept. 21, 1836. 488 M. Boussingault on the Constitution of Bitumens. turpentine, citron, and copaiva. Its vapour, calculated by Dumas’ process, is equal to 9°415, which is double that of the essential oil of turpentine. Supposing that 4 vols. of vapour constitute | eq. of pe- trolene, its composition will be Carbon, .... S80 eqs. = 480 Hydrogen .... 64 eqs. = 64—544 Besides petrolene, there exists in this bitumen a black substance which remains after the separation of the petrolene : this is the solid principle of bitumen. It is very brilliant, of a conchoidal fracture, and is heavier than water ; at about 570° Fahr. it becomes soft and elastic ; it decomposes before it fuses, and burns like the resins, leav- ing a large quantity of coke. The author has called this substance asphaltene, from its forming the base of the minerals which mineralo- gists describe under the name of asphait. Asphaltene may be pro- cured by submitting bitumen purified by ether to a prolonged heat of about 470° Fahr. It is insoluble in alcohol, but zther, the fixed oils, and oil of turpentine dissolve it. It is composed of Warvon 20.670, 75°3 Hydrogen ...... 9°G Oxveen eth 14°8 —100- and may be represented by the formula C+? H2 0%, or by C*° H O85, which indicates that asphaltene results from the oxidation of petro- lene. The bitumen of Bechelbronn purified by ether may then be consi- dered as a mixture of petrolene and asphaltene, at Jeast this is the re- sult of analysis. It contains oN ate i 87:0 Hydrogen ...... 11-2 Oxyren Ls. 1-8—100- It would then appear that the viscid bitumens are mixtures, probably in various proportions, of two substances, which may be separated, and each of which has a definite composition. One of these principles (asphaltene), solid and fixed, resembles asphalt; the other (petrolene), liquid, oily, and volatile, approaches, in some of its properties, to some varieties of petroleum. From this it will be seen that the consistence of bitumens depends on the predominance of one or the other of these principles in the mixture. The analogy existing between asphaltene and asphalt has induced the author to examine whether their respective composition is the same. In consequence of this he analysed the asphalt of Coxitambo, which may be taken as a type of the species. This asphalt has a conchoidal fracture, and is of a brilliant lustre ; its density is 1°68 ; it is dissolved by petrolene and the fixed oils with much greater diffi- culty than artificial asphaltene. Except this difference, which may arise from the cohesion of the particles of the native asphalt, the cha- racters of these two substances are identical. It decomposes before it fuses, and burns, leaving 0°016 of a slightly ferruginous ash. It consists of Carbonie 2? se. 750 Hydrogen ...... 9°5 OSVRCH Te es 15:°5—100. Note.—This analysis would indicate the elementary composition of native asphalt, and the artificial asphalt obtained by M. Boussingault, to be the same. [ 489 J Proceedings of Learned Societies. GEOLOGICAL SOCIETY. May 11. PAPER was read “ On the Silurian and other Rocks 1836. of the Dudley and Wolverhampton Coal-field, fol- lowed by a Sketch proving the Lickey Quartz Rock to be of the same age as the Caradoc Sandstone,” by Roderick Impey Murchison, Esq., F.G.S., V.P.R.S. In previous memoirs the author has shown that the coal-field extend- ing from Dudley into the adjacent parts of Staffordshire is surrounded and overlaid by the lower member of the new red sandstone ; and on this occasion, laying before the Societv an Ordnance map, geologi- cally coloured, he gave, Ist, A general sketch of the structure of the coal-field in descending order: 2ndly, Detailed accounts of the Si- lurian rocks which protrude through the coal measures or lie beneath them: 3rdly, A sketch of the quartz rocks of the Lickey: 4thly, A description of the trap rocks: 5thly, General remarks upon the dis- locations of the stratified deposits, and the dependence of these phe- nomena upon the intrusion of trap rocks. 1. Coal measures.—In most parts of the productive coal-field the coal measures are covered by a considerable quantity of detritus, the greater part of which has been derived from the breaking up of the new red sandstone which once overspread this tract, with which are mixed, especially in the northern part of the field, a few boulders of northern origin and some from the surrounding region. General and detailed sections are then given of the regular succes- sion of the carboniferous strata; for the greater part of which in the neighbourhood of Dudley, and for much valuable information, Mr. Murchison expresses great obligation to Mr. Downing; the best sections of the Wolverhampton field having been afforded by Mr. J. Barker. The principal points of novelty consist in drawing a clear distinction between the upper or thicker measures, which contain the 10-yard coal, generally known as the Dudley coal, and the underlying carbonaceous strata, or ironstone measures. ‘The latter, rising from beneath the 10-yard coal, range to the N.N.E. from Wednesbury and Bilston, in a long tract between the parallels of Walsall and Wol- verhampton, extending to Cannock Chase. At the southern end of the field, emerging from beneath the 10-yard coal, they occupy the ‘district between Stourbridge and Hales Owen, containing the well- known “ fire clay ;” though some of the most valuable of the Wol- verhampton iron-stones, beneath those called the ‘‘ New Mine,” are here wanting, viz. the ‘“ Gubbins,” and ‘* Blue Flats.” This poverty in the lower coal measures extends over all the district south of Dud- ley. In the northern and southern ends of the district these lower measures represent the whole carboniferous system ; and in various natural sections near the Hagley and Clent Hills, the author has de- tected them, in very feeble bands, passing upwards and conformably Third Series. Vol. 9. No. 57. Supplement, Dec. 1836. 3N 490 Geological Society. into the lower new red sandstone. Besides the open works formerly alluded to by him in previous memoirs, Mr. M. now states, that his for- mer conjectures respecting the passage of the 10-yard coal beneath the new red sandstone which flanks it on the east and west have been ve- rified by the efforts of the Earl of Dartmouth, who, after sinking to a depth of 151 yards through strata of the lower new red sandstone, has very recently succeeded by further borings, carried down to the depth of 290 yards, in discovering the 1-foot, 2-foot, and ‘‘Brooch” coal seams, which overlie the 10-yard coal throughout the Dudley field. These operations have taken place at Christchurch, one mile beyond the superficial boundary of the coal-field. Besides the plants so common in all carboniferous tracts, the author has observed the presence of animal organic remains. Unios of several species are abundant; and in the northern or lower part of the field he has extracted fragments of fishes, which have been named by Pro- fessor Agassiz, Megalichthys Hibbertiz, M. Sauroides, Diptodus gibbus ; together with scales, coprolites, &c., proving an identity between the animals deposited in these coal measures and those of Edinburgh, de- scribed by Dr. Hibbert. The same species, it will be recollected, have been pointed out by Sir Philip Egerton as occurring in the N. Stafford- shire coal-field, and one of them has been observed by Mr. Prestwich in the coal-field of Coalbrook Dale. Mr. Murchison, however, re- marks that he has not yet observed any marine remains in these coal measures similar to those of Coalbrook Dale ; and nothing yet found can invalidate the inference that the coal of Dudley and Wolverhamp- ton may have been accumulated exclusively in fresh water. b. Silurian rocks.—The mountain or carboniferous limestone and the old red sandstone, which in so many other parts of England form the support of coal tracts, being wanting, this field reposes directly on rocks which Mr. Murchison proves to consist of the two upper members of the Silurian system, viz. “the Ludlow rocks” and “ Wen- lock limestone.’’* As, however, these rocks rise up irregularly, like separate islands, through the surrounding coal measures, and not in their regular order of superposition, so it was obviously impracticable to have determined their relative age by any local evidences; and hence no attempts could have been made to distinguish the younger from the older deposits, until the structure and organic remains of the different members of the Silurian system, had been fairly worked out in other districts, where these types were fully and clearly displayed in their regular order. 2. Ludlow rocks.—These rocks appear at the surface in three de- tached points in this coal-field, viz. Sedgeley, Turner's Hill, and the Hayes. At Sedgeley they are thrown up in an elongated ellipse, very * There is one spot, however, within the author’s knowledge where the snderground works reached a thick mass of red shale or marl deneath the coal-field ; but the works having been Jong abandoned, no correct know~ iedge of these red rocks can be now obtained. Geological Society. 491 much resembling a large inverted ship, of which Sedgeley Beacon, 630 feet above the sea, may be considered as the keel. The upper Ludlow rock, though not thick, is plainly marked by containing the Leptena lata, the Serpula gigantea, &c., and by overlying a limestone which is in every respect identical with that of 4ymestrey or the middle member of the Ludlow rocks, presenting the same lithological struc- ture, i.e adull argillaceous grey limestone, which among other well- known shells, such as the Terebratula Wilsoni and the Lingula, con- tains also the beautiful Pentamerus Knightii so entirely peculiar to this stratum. As at Ludlow and Aymestrey, this limestone of Sedgeley, known here as the “black limestone,” forms an excellent cement under water. Turner’s Hill, a small elevation between Gornals and Himley, is composed of Ludlow rocks; and the Hayes is a narrow short tongue of the same, with a central band of limestone, which rises at a high angle from beneath the coal measures, on the main road from Stour- bridge to Hales Owen, a portion of the lower Ludlow rock being also well exposed. 2a. ‘* Wenlock limestone.” —This limestone formation is much more largely developed than that of the Ludlow rocks, constituting several ellipsoidal masses near the town of Dudley, which have been long worked, and extensively known among collectors, from the number and beauty of their organic remains. Hence the rock has been usually termed the ‘ Dudley limestone.” As, however, it was impossible to have ascertained in this district the relative age of these rocks, their different members being independently in contact with the coal mea- sures, the nomenclature of the Silurian system already selected is ad- hered to, because in Shropshire the Wenlock limestone, in its fullest standard, rises ont regularly from beneath the Ludlow rocks, and the latter passing beneath the old red sandstone and carboniferous lime- stone (both of which are wanting at Dudley) complete the proofs re- quired. The author therefore entreats geologists not to employ the term Dudley limestone except as the synonym of Wenlock, with which he proceeds to show its lithological and geological identity. This limestone is described in detail at the Castle Hill, Wren’s Nest, and Hurst Hill, in all of which it forms ellipsoidal elevated masses, 500 to 650 feet high, protruding through the coal measures in lines paral- lel to similarly shaped masses of Ludlow rock at Sedgeley; &c., @. e. trending from 10° E. of N. to 10° W. of S. ‘I'wo strong bands of limestone occur in these hills, overlaid and separated from:each other by shale, charged with numerous small concretions of impure lime- stone, the “ bavin” of the workmen. The limestone having been quar- ried out from these bands which have been raised up from a common centre, and disposed with a quaquaversal dip.at high angles, it is evi- dent that the hills themselves would ere now have been demolished, had they been composed throughout of calcareous masses of equal urity; but the ‘‘bavin” or refuse composes the framework of these perforated hills, and preserves their outline. The Wenlock shale, or underlying part of the formation, constitutes the nucleus of the Wren’s Nest, the largest and most perfect of these ellipsoids, and of this the author gives a detailed plan. ‘These ellipsoids usually 3N 2 492 Geological Society. feather off at one extremity with a broken-down margin, and thus complete their resemblance in physical features to ancient craters of eruption*. The greatest superficial extent of the Wenlock formation is in the neighbourhood of Walsall, where it rises both in dome- shaped masses and in rectilinear ridges, running from S.S.W. to N.N.E. parallel to the axis of the Wolverhampton coal-field, of which one of these ridges forms the eastern boundary, the limestone plunging beneath the coal-field at a rapid angle. The other ridge is continuous with the new red sandstone of the Bar-beacon, and is known as the Hay Head lime. In the Dudley or 10-yard coal tract few works have yet proceeded downwards beneath the lower coals, and hence the subjacent Silurian rocks are little known to the miners, A remarkable and accidental discovery of a mass of limestone took place recently near Dudley Port, on the rise side of a great fault, which bounds the downcasts of the coal, called “‘ Dudley Trough.” Having worked out the coal on the upcast side, a shaft was sunk in and upon the southern side of this fault, when at a depth of 208 yards, and about 100 yards below the exhausted coal strata, a mass of limestone was met with, which proved to be near 7 yards thick, and of very goud crystalline quality. Being found to extend in a form more or less ho- rizontal, extensive works were promptly opened in it for the extrac- tion of a rock so precious in the heart of the coal-field. When the author visited it, a considerable cavity had been formed, in which no trace of moisture was discernible, whilst it was known that copious streams of water were flowing in the coal measures overhead. He accounts for this mass of limestone being hermetically excluded from the percolation of water, by the impervious nature of the Silurian shale which separates the coal measures from the limestone, and by the shafts being sunk in the fault itself, which, like other lines of fissure, is filled up with clay and other materials, so closely compacted as to form com- plete dams to water. At the north-western edge of the subterranean excavation the fault was stripped, and the materials of which it is composed having thinned out, the limestone was found in contact with a bed of coal, the edges of which appeared bent, both the coal and the limestone having a slickensides polish. By boring through the limestone a second calcareous stratum was found, thus completing the proofs of identity between this underground mass and that which rises to the surface in the hills of Dudley Castle and the Wren’s Nest. In the northern or Wolverhampton field, where the whole of the coal measures, even to beneath the lowest beds of ironstone, (the blue flats,) are traversed by shafts not exceeding 120 yards in depth, the field has been proved at several points to rest on shale and impure limestone, the equivalents of the Ludlow and Wenlock formations. For lists of the fossils in this group of Upper Silurian rocks the author refers to previous memoirs, announcing that more perfect lists will shortly be laid before the public in his large work upon the Silurian system. * See account of Valley of Woolhope for similar phenomena on a larger scale, and with a greater number of concentric and enveloping formations. —Lond, and Edinb. Phil, Mag., vol. iv. p. 372. Geological Society. ‘ 493 3. Lickey Quartz rock, Caradoc sandstone, (Lower Silurian rocks.) Dr. Buckland first called the attention of geologists to the Lickey quartz rock* ; and, showing that it had been one of the principal ma- gazines of the quartz pebbles in the new red sandstone and diluvium of the southern counties, he further compared it with certain rocks in situ in the neighbourhood of the Wrekin. ‘The Rev. J. Yates has also clearly described the lithological structure of this rock, and has briefly touched uponsome of its fossils}. Mr. Murchison undertakes to prove the true geological position of these rocks. He shows that they lie in the direct prolongation of the Silurian rocks of Dudley, and that, being partially flanked and covered by thin patches of coal, they emerge through a surrounding area of the lower new red sandstone and calcareous red conglomerate (described in previous memoirs). Unlike, however, the succession in the Dudley field, there are here no traces of the Ludlow rock and Aymestrey limestone. Nor are there masses of any size of the Wenlock limestone, but shreds only of the shale or lower part of this formation with some of its well- recognised fossils, (Colmers.) The lower Silurian rocks rise from beneath the Wenlock shale in thin courses of bastard limestone, alternating with red and green courses of sandstone and shale, the equivalents of those bands, which at various places in Shropshire, andat Woolhope in Herefordshire, con- stitute the top of the formation of Caradoc sandstones. Like these, they are here underlaid by flaglike sandstones, sometimes rather more ar- gillaceous and approaching to clay slate, the whole passing down into siliceous sandstones, both thick and thin bedded. In the latter are casts of several fossils of the Caradoc formation, such as Pentameri of two species, and corals peculiar to it. These fossilliferous strata are well exposed on the eastern side of the hills by recent cuttings, where: the new road from Bromsgrove to Birmingham traverses the ridge. The ridge itself, however, consists essentially of quartz rock, which the author shows is nothing more than altered Caradoc sandstone, precisely analogous to that which he has on former occasions pointed out on the flanks of Caer Caradoc, the Wrekin, Stiper stones, &c. In those districts the passage from a fossiliferous sandstone to a pure quartz rock has been accounted for by the latter being in absolute contact with eruptive masses of igneous origin; and here it is sug- gested that the same cause may have operated, though the contact is not visible, because the line of quartz rock is precisely upon the pro- longation of the trappean axis of the Rowley Hills, whilst the southern end of the parallel outburst of the Clent Hills, is but little distant. Notwithstanding their highly altered condition, it is shown that all the quartz rocks throughout this ridge of low hills are uniformly stra- tified, the dip being either to the E.N.E. or W.S.W., i. e. at right angles to the direction; and the parallelopipedal fragments into which: the rock breaks are shown to be produced by fissures more or less at right angles to the planes of stratification ; these fissures being so * Transactions Geol, Soc., Ist Series, vol. v. p. 507. + Transactions Geol. Soc., 2nd Series, vol. ii, p. 137.—[Also Phil. Mag., First Series, vol. Ixv. p. 297.] 494 Geological Society. numerous where the mass is much altered, as almost to obscure the true laminze of deposit. 4, Trap—The composition and characters of the trap rocks and basaltic masses of the Rowley Hills are first described, together with the manner in which they are supposed to rise through and cut off the coal upon their flanks. Rocks of similar origin occur at various detached points to the west of Dudley, of which Barrow Hill is the principal, affording the most convincing proofs of the voleanic mass having burst through the carboniferous strata, since the latter are not only highly disturbed and broken, but fragments of coal and coal mea- sures, in highly-altered conditions, are found twisted up upon the sides, and even mixed with the trap itself. In the Wolverhampton or north- ern coal-field, the chief vent of eruption is at Pouk Hill, two miles west of Walsall, where the greenstone is arranged in fan-shaped columns. After pointing out distinct evidences of the intrusion of similar rocks at Bentley Forge and the Birch Hills, in some of the old open works near which the trap is seen to overlie the coal, the author gives vari- ous sections of subterranean works, which prove the existence of greenstone, in bands more or less horizontal. As these bands of trap have jagged edges, are of limited extent, of exceeding irregularity in thickness, and often produce great alteration upon the inclosing carbonaceous masses, the author has no hesitation in expressing his belief that they are not true beds, but simply wedges of injected matter which have issued from central foci, and have been intruded laterally amid the coal strata; an opinion formerly expressed by Mr. A. Aikin in an able memoir*, Although these lateral masses of greenstone in the Wolverhampton field are of origin posterior to the accumulation of coal strata, the author does not deny that the tufaceous conglomerates of Hales Owen, which have a strong analogy in composition to a certain class of vol- canic grits described in former memoirs, may have been formed con- temporaneously with the carboniferous deposits. The trap of the Clent Hills is then briefly described, and is shown to be identical with that of the Abberley Hills, also mentioned in pre- vious memoirs. 5. Principal lines of dislocation.—The whole of this carboniferous tract has been upcast through a cover of new red sandstone, the lower mem- bers of which are frequently found to have been dislocated conform- ably with the inferior carbonaceous masses, proving (as formerly ex- pressed by Mr. Murchison) that some of the greatest of these move- ments took place subsequently to the deposit of the red sandstone. In describing the faults along the boundary of the new red sandstone, he directs particular attention to that of Wolverhampton, where the coal measures dip slightly inwards from the line of fissure, along which they are conterminous with the overlying strata, a fact perhaps without parallel in this or the adjacent coal-fields (including Coalbrook Dale), the usual phenomena being that, however disrupted, the carbonaceous or upcast strata always incline outwards, as if they would pass even- tually beneath the lower new red sandstone on their flanks. This * Transactions Geol. Soc., Ist Series, vol. ili. p. 251. Geological Society. 495 exception is supposed to have been caused by the upheaving of a subjacent mass of Silurian or trap rocks close to the edge of the line of fault. Having next described the effect of the great longitudinal faults produced by the upcast of the Wenlock limestone of Walsall, he shows that the subterranean mass at Dudley Port (p. 492), is upon the same parailel, i. e. from N.E. to S.W., if not directly on the same line of fis- sure. This line of eruption is strongly marked on both edges of the northern half of the coal-field extending to Cannock Chase. Another great axis of elevation which affects the Dudley field, di- verges at a considerable angle from the former. It is prominently marked by the line of the Rowley Hills, and after concealment for 2 certain distance beneath the red sandstone to the S. of Hales Owen, reappears in the ridge of the Lickey quartz rock. The lofty trappean ridge of the Clent Hills is parallel to this last-mentioned axis. It is further pointed out as remarkable that at the angle formed by the confluence of these divergent lines of elevation, the Silurian or fun- camental rocks of the tract are raised in inflated ellipsoidal forms from common centres, the strata having a quaquaversal dip, in one case completing the outlines of a very perfect valley of elevation. The author infers that such curvatures are exactly what might be ex- pected at the point of greatest flexure in the axis of the coal-field, where the volcanic matter, unable to find issue, has produced these inflated masses. ‘There are numberless faults in this coal-field to which no reference is made, it being stated that much additional labour is required to give a complete history of them ; but attention is called to the Birch Hill, Lanesfield, and Barrow Hill faults, which are the principal transverse faults, and which the author conceives may be ex- plained upon the principles of the theory of Mr. Hopkins, or as cross fractures which have resulted from elevation of the coal- field en masse. The memoir concludes with referring to the importance of one of the problems to which the author has been directing public attention during the last few years, viz. the probable extension of carboniferous tracts of the central counties beneath the surrounding new red sand- stone; and he rejoices that the deductions which necessarily follow from his observations in this and the adjacent coal-fields, have recently been so ably supported by the masterly observations of Mr. Prestwich upon Coalbrook Dale, with whose opinions he entirely coincides. The quantity therefore of unwrought coal beneath the new red sand- stone of Shropshire, Worcestershire, Staffordshire, &c. though pre= viously omitted in statistical data, must form an element in all caleu- lations concerning the probable duration of the carboniferous wealth of the empire. May 25.—A paper was first read ‘On the part of Devonshire be- tween the Ex and Berry Head and the Coast and Dartmoor ;” by Robert Alfred Cloyne Austen, Esq., F.G.S. The formations of which the district consists are transition rocks, new red sandstone, greensand, and trap. The transition rocks are sometimes arenaceous, more often slaty, and contain beds of limestone rich in organic remains, The only portion 4.96 Geological Society. of the system considered by the author as undescribed is a conglo- merate, 100 feet thick, which occurs at the Park at Ugbrook. It is com- posed of rounded quartz pebbles and fragments of clay slate, united by a siliceous cement. It alternates in the upper part with beds of clay slate, and is older than any of the limestones of the country. These transition formations are traversed by numerous faults, the strata being thrown into the wildest confusion. In some places beds of trap are regularly interposed without producing any effect upon the adjacent strata; but in other localities dykes intersect the sedimentary deposits, and have produced great alterations both in their structure and dip. The new red sandstone consists in the lower part of fine-grained fissile sandstone, and a coarse conglomerate, formed out of the surround- ing older formations, including partially rounded fragments of slate, limestone, porphyry, greenstone, &c. ‘This formation is also much disturbed by faults, some of which, the author thinks, are contempo- raneous with the deposition of the sandstone, as they appear to affect the lower and not the upper beds in the same section. The elevation of the greensand of the Haldons, Mr. Austen thinks, was due to the action of asubjacent mass of trap, portions of which are visible at the extremities of the hills: and he is of opinion that the preservation of these insulated patches of greenstone has been owing to their having been raised above the level of the waters which denu- dated the surrounding districts. In conclusion the author briefly reviews the geological phenomena which this part of Devonshire presents, and infers from them, that du- ring the transition epoch there were submarine volcanic irruptions, as shown by the interstratified trap; that the number of organic remains in the limestone prove that the ocean teemed, in parts, with life: that the new re.| conglomerate was due to the breaking up of the transition formations : that there were irruptions of trap at later periods, as proved by the dykes in the new red sandstone; and that Dartmoor was ele- vated after the deposition of the greensand, as the first traces of gra+ nitic debris are found in the Bovey deposit. . A notice was nextread on the supposed existence of the Lias forma- tion in Africa, by Roderick Impey Murchison, Esq., F.G.S. Mr. Leach, of Milford Haven, a short time since presented to the Society some organic remains, stated to have been obtained by Com- modore Sir Charles Bullen on the west coast of Africa. As these or- ganic remains agree exactly with fossils of common occurrence at Lyme Regis, it was conjectured that some mistake might have occurred re- specting them; but Mr. Leach has been subsequently informed by Sir Charles Bullen that they were collected by himself and officers at West Bay, Fernando Po, Accra, andSierra Leone, and that they occur in abundance. Mr. Murchison also announced in this notice, that Sir John Herschel has discovered Trilobites in a rock which occurs to the north of the Cape of Good Hope. A paper was then read, entitled ‘‘ A Notice on Maria Island, on the east coast of Van Diemen’s Land, (S. lat. 42° 44' E., long. 148°8',) by George Frankland, Esq., Surveyor-General of the Colony; and Geological Sociely. 497 communicated to the Society by Robert W. Hay. Esq., Under Secre- tary of State for the Colonies. Maria Island is composed, for the greater part, of trap; but strata of freestone well calculated for building purposes frequently occur, and at the northern point of the island is a perpendicular cliff, from 200 to 500 feet high, composed of dark grey limestone, formed of oysters, muscles, and other shells, in a state of great preservation. On the eastern coast, near Cape Mistaken, are numerous caverns, some at the height of 600 feet above the level of the sea, the roofs of which are studded with stalactites. Mr. Frankland states that Van Diemen’s Land in every part furnishes strong evidence of the ocean having once occupied a much higher level than at present. The paper also contains much valuable information respecting the natural pro- ductions of the island. A letter was next read on the geology of the country included in the S.W. quarter of the Daventry, or 55th sheet of the Ordnance Survey, by J. Robison Wright, Esq., F.G.S., and addressed to Capt. Mudge, R.E., F.G.S, The surface contained in this quarter sheet is about 168 square miles, including the towns of Southam and Kineton, and the field of the battle of Edge Hill. The formations of which the district consists are the new red sandstone, the lias, and the inferior oolite. A notice on the occurrence of marine shells in a bed of gravel at Narley Bank, Cheshire, by Sir Philip Grey Egerton, Bart., M.P., F.G.S., was then read. In proceeding from the valley of the Weaver, at the point where it is crossed by the Liverpool and Birmingham Railway, towards Dela- mere Forest, are two acclivities, each about 60 feet high, and distant about a mile and a half from each other. Narley Bank is situated on the summit of the second ridge, and the gravel-pit is in the face of the northern declivity, about 157 feet above low-water mark at Weston Point, and six miles from it. The gravel differs from the common gravel of the country by the prevalence of calcareous matter and the small proportion of fine sand; but agrees with the gravel at the Wil- fington, described in a former paper*. This resemblance induced the author to search for shells, and he found, at a second visit to the pit, several imperfect fragments of apparently recent marine shells. In conclusion, Sir Philip Egerton states that he has always found a marked distinction, in Cheshire, between the gravel containing re- cent shells and that which does not ; and he infers, from the former being occasionally covered, as at the Willington, by a thick deposit of sand and gravel, that it was accumulated before the occurrence of the last drift, to which he ascribes the origin of the common detritus of the county. A paper was afterwards read, entitled “‘ Accompanying remarks to a section of the Upper Lias and Marlstone of Yorkshire, showing the limited vertical range of the species of Ammonites and other Testacea, with their value as geological tests,” by Louis Hunter, Esq., and communicated by John Forbes Royle, Esq., F.G.S. * Lond. and Edinb. Phil. Mag., vol. vii. p. 326. Third Series. Vol. 9. No. 57. Supplement Dec. 1836. 30 498 Geological Society. The portion of the coast to which this paper immediately refers is called the Easington Height, situated between Whitby and Redcar, and presents the following details : INFERIOR OOLITE. Upper Lias Shale. HIE cea eee a '-' EPL Se ors tae RE Sit 35 feet Hard ‘or cement stone bed... ose ss ce ie 25 Shale, containing nodules of ironstone........ 90 SPOT TOCKE MCE mice ris sorcerers aia 20 to 30 Hard compact sandy shale ....... Prepeabaas: 30 about 200 Marlstone. Thin seams of shale, alternating with hard iron- stone bands, a foot thick... ........ nigga Sandy shale, with beds of dogger ...... pee Oey 8 63? Alternating beds of calcareous sandstone and SANU YP SUMIC a tc cere ar aclac/Roh he ke sia ous 40 Shaly sandstone, passing gradually into the lower HAS RTE ete cele che on, eit adn ries cia ace 30? — 160 TIDE) AUB OS OTNE shu A tah ph crc aia ceniele, Fcusssivgn acs pk aie cece 150 The beds of shale superior to the jet rock are characterized by the presence of Nucula ovum, Orbicula refleca, Plagiostoma pectinoide, Ammonites communis, A. heterophyllus, A. fimbriatus, A. Walcottii, A. subcarinatus, A. angulatus, A. crassus, A. fibulatus, A. subarmatus, A.Lythensis, A. Boulbiensis, A.annulatus, Nautilus astacoides, and Belemnites elongatus. The species gradually decrease in abundance on approaching the jet rock, and the specimens which do occur in that stratum are stated to be smaller than in the higher beds. The jet rock contains a peculiar suite of Ammonites, viz. 4. elegans, A. sig- nifer, A. elegantulus, A. exaratus, A. Mulgravius, A. concavus, and A. ovatus. It is also distinguished by containing the remains of the gavial-snouted crocodile. With respect to the relative abundance of the fossils, Mr. Hunter observes that where they occur in the greatest number they are smallest in size, ' The beds situated between the jet rock and the marlstone are very poor in fossils. The marlstone series is distinguished not only by a change in the species, but in the preponderance of bivalves and the comparative ra- rity of Ammonites ; the characteristic fossils being Avicula cygnipes, A. inequivalvis, Pecten sublevis, P. equivalvis, Pullastra antiqua, se- veral species of Terebratula, Cardium truncatum, Modiola scalprum. The species of Ammonites are few, 4. vittatus occurring about the centre of the series, and 4. maculatus at the junction with the lower lias shale. In conclusion, Mr. Hunter states that the difference between the distribution assigned to the fossils by himself and other authors may be owing to the prevalent practice of collecting fossils from subsided masses, and not from undisturbed portions of the cliffs. Geological Society. 499 A letter was, lastly, read from Robert Fitch, Esq., of Norwich, to Edward Charlesworth, Esq., F.G.S., on the discovery of the Tooth of a Mastodon in the crag at Thorpe, near Norwich. The pit in which the tooth was found is stated to present the fol- lowing section : Mp CMA VTRRE SOLIS Pe in die hats = tm ter =e 5 feet MGtaivele fe) PS eS St Soon estes ae 6 Brick-earth, sand, and gravel ........ 14 Crap a men. See ates cence eerie ae 5 Large chalk flints, mixed with crag shells, principally Pectens.,........-.--- Brea oe Teh Mins a etait einiats gis sre It was in the bed of large chalk flints that Mr, Fitch found the tooth; and he adds that Thorpe adjoins the parish of Whitlingham, in which Mr. William Smith discovered the tooth figured in his * Strata Identified.”’ June 8.—A paper was first read, entitled,“ Notice respecting a piece of Wood partly petrified by Carbonate of Lime; with some remarks on Fossil Woods, which ithas suggested.” By Charles Stokes, Esq., F.G.S. Mr. Stokes lately received from Germany, with a collection of fossil woods, a piece of recent wood, stated to have been found in an ancient Roman aqueduct, in the principality of Lippe, in the Biickeberg, in which some parts are petrified by carbonate of lime, while the remainder of the wood, though in some degree decayed, is not at all mineralized. This fact has afforded an explanation of the peculiarities of some other instances of fossil wood, in which different parts of the specimen pre- sent different appearances. Two other instances are particularly de- scribed: one of silicified wood from Antigua, and one of a calcareous petrifaction from Allen Bank in Berwickshire. In both these cases it is inferred by the author, that the process of petrifaction com- menced simultaneously at a number of separate points, and that it was suspended when only parts of the wood had been petrified. The unchanged parts would then be liable to decay; and in the specimen from Antigua the process has been renewed after this remaining part had decayed in a considerable degree, when that also became silici- fied. In the calcareous petrifaction from Allen Bank (which is de- scribed and figured by Mr. Witham, in his work on the structure of fossil vegetables), the parts which had not been petrified at the time the process was interrupted, have been entirely destroyed by the de- cay which then ensued, and the intermediate spaces have been filled up by the crystallization of carbonate of lime, without the removal of the petrified portions from the positions in which they grew and in which they had become mineralized. In the specimen from the Roman aqueduct the petrified portions run in separate columns through the wood, as if conducted down- wards by the vessels or woody fibres. In that from Allen Bank the separate portions are spherical in form and independent of each other ; and in that from Antigua they are independent, and though nearly spherical not regularly so. Hence the author infers that a different explanation must be sought for the manner in which the solution of 30 2 500 Geological Society. mineral matter was supplied in the first instance from. that of the two last. The paper notices also the fossil wood from Lough Neagh and Bonn, in which some small parts preserve their texture, although re- maining still unchanged in the midst of the petrified mass. The author concludes with a short notice of the different conditions in which the structure of wood is preserved in different specimens, and considers that the condition of the woud has not any influence on the process of petrifaction. A paper was next read, entitled, ‘‘ Further notice on certain pecu- liarities of Structure in the Cervical Region of the Ichthyosaurus,” by Sir Philip Grey Egerton, Bart., M.P., V.P.G.S. In a former communication* Sir Philip Egerton gave an account of the cervical vertebre. of the Ichthyosaurus, and announced the dis- covery that the atlas and axis are firmly united and strengthened be- low by an accessory articulating bone. In this paper he shows, that the union of the two vertebre is perfect at all periods of the animal’s growth, and apparently in all the species of the genus hitherto dis- covered, having observed it in vertebre varying in size from half an inch to seven inches and a half in diameter. Externally there is a strong line of demarcation between the two bones, but internally the cancelli appear to pass from one to the other. The atlas, indepen- dently of the union of the two vertebra, is distinguished by the form of the anterior cavity for the reception of the basilar process of the occipital bone ; by the outer margin being rounded instead of sharp, and by the triangular facet on the inferior part of the circum- ference for the reception of the accessory bone: the axis, indepen- dently also of its union with the atlas, differs from the other vertebre, by the facet on the under surface for the reception of the accessory bone: and the third vertebra is also distinguished from the remaining bones of the neck by a facet for the articulation of a very small accessory bone. The intervertebral cavities of the 4th and Sth cervical verte- bre, the author states, are less than in the vertebre of the dorsal and caudal regions, and the anterior cavity is considerably smoother than the posterior one of the same vertebre. Sir Philip Egerton states that the spinal column does not, as de- scribed by other authors, decrease in diameter from the middle dorsal vertebra to the atlas, but that the minimum diameter is attained about the fifth cervical vertebra, from which point to the occipital bone the increase in size is very rapid, the atlas being fully one fifth more in: diameter than the above-mentioned bone. In the former memoir Sir Philip Egerton described only one acces- sory bone in the cervical region of the Ichthyosaurus ; but in this paper he proves that there are three, and proposes to designate them by the name of subvertebral wedge-bones. One of them is supplementary to the atlantal socket, another is common to the atlas and axis, and- the third, which agrees in form with the second, but is much smaller, articulates on the under surface of the third vertebra. The author, then, in conclusion, enlarges upon the admirable * Lond. and Edinb, Phil. Mag., vol. vii. p. 414. Geological Society. 501 adaptation of the structure of the Ichthyosaurus to the habits of the animal, A communication was afterwards made “ On the coal-fields on the north-western coast of Cumberland, &c., &c.:” by the Rev. Pro- fessor Sedgwick, M.A., F.R.S., F.G.S., and Williamson Peile, Esq., of Whitehaven, F.G.S. In a former paper* the authors described the range of the carboni- ferous limestone from the neighbourhood of Kirkby Stephen to Egremont; and showed that the formation admitted of two divi- sions : the lower representing the scar limestone of the Yorkshire sections, the upper (also like the Yorkshire sections) exhibiting alternations of limestone, sandstone, and shale, w.th thin seams of coal. They commenced with a short notice of rocks and sections made through this upper division, which in its range towards the western coast of Cumberland, appears gradually to thin off, and lose its importance. They then proceeded to describe in more detail, and with many illustrative sections, a still higher coal-field ; which is on the same parallel with the great Northumberland and Durham coal-fields, and in the quantity of carboniferous beds subordinate to it, is in no respect inferior to them. This field is bounded by the red sandstone of St. Bees Head ; by the carboniferous limestone, in a part of its range above described; by the sea coast between St. Bees Head and Maryport; and by the new red sandstone in its range from Maryport to Chalk Beck near Rosley. The whole system appears to thin off near Rosley, and is succeeded by some sterile, alternating, masses of red shale and sand- stone, to which the miners, though improperly, have given the name of the “ great red metal dyke.’ ‘To the east of this series of red beds the rich upper coal-field never appears to have extended. From many borings and workings near Whitehaven, it is inferred that the upper division of this carboniferous limestone, as well as the millstone grit, have almost disappeared; and that the coal measures are brought nearly into immediate contact with the lower division of the limestone. In some places the whole limestone has thinned off, and the coal measures seem to rest almost immediately on the Skiddaw slate. The authors commence their details, in the present paper, with an account of the Whitehaven coal-field, which they separate into three divisions : the southern, or How-Gill colliery ; the middle, or Town field bounded by a great downcast dyke towards the north; and the northern, or Whin-Gill colliery, bounded by an anticlinal line which enters the sea near Parton. ‘The strata found in these several parts of the field are described by the help of the sinkings and borings of Croft Pit, and by o.her si.kings in various parts of the field down to the limestone. A comparison is then made between this series of strata and those exhibited in corresponding sections of the Harring- ton and Workington fields; and it is shown that the whole series may be conveniently separated into two divisions: the upper, con- taining two principal bands of coal, called the “ Bannock Band,” and * Proceedings Geol. Sac., vol. ii. p. 198. 502 Geological Society. Whitehaven “ Main Band”; the lower, containing many thin seams of coal, but only one band which has been much worked near White- haven. They then proceed to describe the most remarkable workings in the several divisions of the Whitehaven field; the new field to be approached by the Parton tunnel ; and the extension of the ‘ Main and Bannock band” to the hills S.E. of Dissington; but these de- tails, as well as an account of the works attempted in a small trian- gular field bordering the sea to the north of Parton, are necessarily passed over in this abstract. They then describe the Harrington coal-field, bounded to the north and south by two enormous faults ; between which the coun- try is occupied by the lower division of the coal measures. It is impossible in an abstract to describe the complicated faults that everywhere intersect this field,and by which the limestone is in two instances brought up to the surface. The coal beds, worked within it, are five in number, and are described, in descending order, un- der the following names: (1.) Metal Band; (2.) Two-feet Band ; (3.) Yard Band; (4.) Four-feet Band; (5.) Yendale Band. By help of a transverse section to Castlerigg, this field is connected with the upper division of the coal measures; in as much as pits have been sunk near that place, through the great beds of the upper division, down to the two-feet band ; thus giving a consistency and unity to all the sections. The authors next describe the Workington field, bounded to the south by the great fault which brings in the lower division of the Harrington field ; and to the east and west by the sea and the turn- pike road. The river Derwent was formerly regarded as its north- ern boundary ; but the mazn band unfortunately thins out alittle to the south of Workington, and thereby contracts the extension of the valuable part of this field. Nearly all the beds worked in this field belong to the upper division ; and their general agreement with the Whitehaven bands of coal is proved by detailed sections ; especially from the sinkings at Henry Pit near the mouth of the Derwent. The principal faults traversing this district, the outcrops of the prin- cipal bands of coal, and the extension of the works under the sea are described in some detail, Several other small divisions of the great field are then noticed: viz. the Starmire, Keekhill-Side, Brownrigg, Branthwaite-Edge, Gillgaron, and Graysouthern fields ; after which the authors proceed to describe the phenomena on the north side of the Derwent. To the north of the Derwent, there is near the sea-coasta sterile region, partly occupied by the lower red sandstone, and partly by the upper division of the coal measures, in which the main coal is wanting ; a fact connected with the thinning off of the main band to the south of Workington, Ina very extensive field, commencing alittle to the N. of the village of Seaton, and extending over Brough- ton Moor, and from thence to Dearham, two beds of coal (known by the names of the ‘‘ten-guarter band” and the ‘kernel and metal band”) have been very extensively worked, and are identified with the “ ban- nock-band” and ‘‘ main-band” of Whitehaven and Workington. The relations of the several parts of this extensive tract of country Soological Society. 503 are exhibited in detailed sections, of which it is very difficult to convey a notion in a mere abstract; and the works carried on within them are, with very limited exceptions, referred to the upper division of the Whitehaven field. . The coal bands exhibited in the works near Gillerux, Aspatria, Plumland, and Weary Hall are then described ; and detailed sections are given of the works in the Bolton field,—generally regarded as the north-eastern limit. There is, however, an unexplored tract to the east of a great fault which forms the northern limit of the Bolton field ; and, in the neighbourhood of Rosley, a seven-feet coal; un- doubtedly a member of the upper division) was formerly worked ) though to a very small extent, in consequence of the complicated dislocations which intersect the district. Having described, in the above order, the several portions of the great coal-field, and noticed some of its peculiarities of mineral struc- ture, the authors endeavour toascertain the limits of certain outlying masses of the lower red sandstone, of the magnesian conglomerate, and of the new red sandstone. From the facts stated, it appears that the coal measures pass, in some instances, in regular ascending order, into the lower redsandstone. In other instances, however, the coal measures appear to have undergone considerable movements of ele- vation before the existence of the lower red sandstone; in as much as the position of the two formations is discordant, Again, though the lower red sandstone forms the natural and immediate basis of the magnesian limestone and conglomerates, yet there are several places, within the south-western limits of the country described, where the conglomerates appear to have been deposited in hollows and inequalities presented by the waterworn beds un which they rest unconformably. From which facts it seems to follow, that the formations described in this paper have undergone, during their de- velopment, two considerable movements, affecting the position of the component strata: Ist, a partial movement of the coal measures, anterior to the deposition of the lower red sandstone ; 2ndly, a par- tial movement, both of the coal measures and the lower red sand- stone, anterior to the formation of the magnesian conglomerates. This being the last evening of the Session, the Society adjourned, at its close, to Wednesday, November the 2nd. ZOOLOGICAL SOCIETY, May 10.—The following Note by the Rev. H. Dugmore was read. “Lieut. Col. Mason, of Neeton Hall (four miles from Swaffham), has had a Sea Eagle, Haligetus albicilla, Sav.,in confinement for the last sixteen years. About amonth since, it dropped an egg, which is now in my collection. The egg is perfectly white, and not quite so large as that of a Goose: the shell is rather harder.” A letter was read from Capt. Green of Buckden, Huntingdonshire, descriptive of a very fine specimen of the barn-door Hen in his pos- session, which has assumed the Cock plumage: the change took place about three years ago. ‘The bird has since been presented to the Society by the writer. 504 Zoological Society. Mr. Owen read the following Notes on the Anatomy of the Wom- bat, Phascolomys Wombat, Pér. « The anatomy of the Wombat having already engaged the atten- tion of Cuvier (‘Legons d’Anat. Comparée, passim) and Home (Phil. ‘Trans. vol. xcvili. 1808, p. 304,) but little remains to be added on that subject. «« ‘The individual lately dissected at the Museum of the Zoological Society had lived at the Gardens upwards of five years. The one which was dissected by Sir Everard Home in 1808 was brought from one of the islands in Bass’s Straits, and lived as a domestic pet in the house of Mr. Clift for two years. This animal measured two feet two inches in length, and weighed about 20lbs.: it was a male. The Society’s specimen was a female, and weighed, when in full health in October 1833, 594]bs. “« On removing the integuments of the abdomen, much subcuta- neous fat, of the lard kind, was observed. «