w^m^- .•^r%> ^5 V- 4^4im r.^ ^ w^-i- THE LONDON AND EDINBURGH PHILOSOPHICAL MAGAZINE AND JOURNAL OF SCIENCE. CONDUCTED BY SIR DAVID BREWSTER, K.H. LL.D. F.R.S. L. & E. &c. RICHARD TAYLOR, F.S.A. L.S. G.S. Astr. S. &c. AND RICHARD PHILLIPS, F.R.S. L.&E.F.G.S. &c. " Nee aranearum sane textus ideo melior quia ex se fila gignunt, nee nosier vilior quia ex alienis libamus ut apes." Just. Lips. Monit. Polit, lib. i. cap. 1. VOL. VL NEW AND UNITED SERIES OF THE PHILOSOPHICAL MAGAZINE AND JOURNAL OF SCIENCE. JANUARY-JUNE, 1835. LONDON: PRINTED BY RICHARD TAYLOR, RED LION COURT, FLEET STREET, Printer to the University of laondon. SOLD BY LONGMAN, REES, 0»ME, BROWN, GREEN, AND LONGMAN; CADELL; BALDWIN AND CRADOCK; SHERWOOD, GILBERT, AND PIPER; SIMPKIN AND MARSHALL; AND S. HIGHLEY, LONDON: BY ADAM BLACK, EDINBURGH; SMITH AND SON, GLASGOW; HODGES AND M'ARTHUR, DUBLIN; AND G. G. EENNIS, PARIS. TABLE OF CONTENTS, NUMBER XXXI.— JANUARY. Page Mr. J. F. W. Johnston on the Dimorphism of Baryto-calcite. . 1 Rev. Patrick Keith on the Structure of Animals 4 Rev. Baden Powell's Abstract of the essential Principles of M. Cauchy's View of the Undulatory Theory, leading to an Explanation of the Dispersion of Light ; with Remarks .... 16 Dr. C. J. B. Williams's Observations on the Production and Propagation of Sound 25 Dr. Faraday's Experimental Researches in Electricity. — Eighth Series 34« Dr. Olbers on the approaching Return of Halley's Comet 45 Mr. R. Phillips on the Quantity of Water contained in cry- stallized Barytes and Strontia 52 New Books: — Allan's Manual of Mineralogy, comprehending the more recent Discoveries in the Mineral Kingdom 53 Proceedings of the Royal Society 55 Geological Society 63 Zoological Society 68 Linnaean Society 72 Cambridge Philosophical Society 73 Royal Medals to be awarded by the Council of the Royal So- ciety, for the most Important Discoveries and Investigations in Science, in the years 1833 and 1837 75 Mr. W. C. Trevelyan on the Occurrence of Fragments of Gar- net in the Millstone Grit — Mr. H. J. Brooke's Mineralogical Notices 76 On the Juice of Eschscholzia Californica — Herrmann Prick's Analysis of Nadelerz 77 Ammonia in the Vegetable Alkalies , 78 M. Horace Demar9ay on the Employment of insoluble Salts in Analysis 79 Meteorological Observations made by Mr. Thompson at the Garden of the Horticultural Society at Chiswick, near London, and by Mr. Veall at Boston 80 NUMBER XXXII.— FEBRUARY. Mr.D. Mushet on the Practicability of alloying Iron and Cop- per 81 Mr. A. Trevelyan's Further Notice of the Vibration of Heated a 2 ir CONTENTS. Page Metals; with the Description of a new and convenient Ap- paratus for experimenting with 85 Mr.W. G. Horner on the Signs of the Trigonometrical Lines 86 Rev. P. Keith on the Structure of Animals {concluded) 90 Prof. T. Everitt on the Reaction which takes place when Ferro- cyanuret of Potassium is distilled with dilute Sulphuric Acid ; with some Facts relative to Hydrocyanic Acid and its pre- paration of uniform strength 97 Prof. W. H. Miller on the Forms of Sulphuret of Nickel and other Substances 104? Rev. Baden Powell's Abstract of the essential Principles of M. Cauchy's View of the Undulatory Theory, leading to an Explanation of the Dispersion of Light; with Remarks {continued) IO7 Mr. R. H. Brett and Mr. G. Bird on the Existence of Titanic Acid in Hessian Crucibles 113 Mr. J. W. Lubbock on some Elementary Applications of Abel's Theorem 116 Dr. Faraday's Experimental Researches in Electricity. — Eighth Series {continued) , 125 Sir David Brewster's Notice of the Optical Properties of a new Mineral supposed to be a Variety of Cymophane 133 Prof. J. D. Forbes on the Refraction and Polarization of Heat 134? Proceedings of the Royal Society 14-2 Geological Society 146 ■ Zoological Society 150 Royal Geological Society of Cornwall 153 Cobalt Blue Colours 156 M. C. Matteucci on the Influence of Electricity in Germina- tion 157 Mr. H. A. Meeson on the Detection of Opium ; and on a new Test for Morphia and Quina J58 Fall of a Meteorite in Moravia 1.59 Meteorological Observations 160 NUMBER XXXIll.— MARCH. Sir David Brewster's Observations on the supposed Acliroma- tism of the Eye ^ jgj Dr. H. Johnson on the General Existence of a newly observed and peculiar Property in Plants, and on its Analogy to the Irritability of Animals I54 Mr. E.M. Clarke on a new Phaenomenon in Magneto- Electri- city 159 Mr. J. Thomson's Note relative to the Form of the Fibres of Cotton 2 "70 CONTENTS. V Page Dr. Faraday's Experimental Researches in Electricity. — Eighth Series {continued) 171 Dr. J. Apjohn's Formula for inferring the Dew-point from the Indications of the Wet-bulb Hygrometer 182 Rev, Baden Powell's Abstract of the essential Principles of M. Cauchy's View of the Undulatory Theory, leading to an Explanation of the Dispersion of Light j with Remarks {continued) 1 89 Prof. T. Everitt's (Economical Means of procuring pure the Salts of Manganese, and of analysing the Minerals which contain Manganese and Iron, &c 193 Mr. C. Blackburn's Analytical Theorem relating to Geometri- cal Series 1 96 Mr. G. O. Rees on the Presence of Titanic Acid in the Blood 201 J. B. on the Attraction of an Homogeneous Ellipsoid on an external Particle 203 Prof. J. D. Forbes on the Refraction and Polarization of Heat {continued) 205 New Books: — Parkes's Chemical Catechism, by Brayley .... 214? Proceedings of the Linnsean Society 220 Royal Astronomical Society 221 . Zoological Society ! 223 Mr. Sturgeon on an Aurora Borealis seen at Woolwich on December 22, 1834. 230 Mr. Gill on the Structure of the Fibres of Flax and Cotton, in Reference to the Observations of Mr. Bauer 231 Dr. Gale on Professor Mitchell's Method of preparing Car- bonic Oxide 232 Carbonate of Stronlia discovered in the United States — Sepa- ration of some Metallic Oxides 234 Separation of Oxide of Cadmium and Oxide of Bismuth — Ac- tion of Muriate of Ammonia on certain Sulphates 235 Peroxide of Iron as an Antidote to Arsenious Acid 237 Improved Compass- Needles — Analyses of Osmiridium and Allanite 238 Mr. F. Watkins's Observations on Mr. Sturgeon's Letter con- tained in the Lond. and Edinb. Phil. Mag. for November 1834. 239 Meteorological Observations 240 NUMBER XXXIV.— APRIL. Mr. Brayley 's Notice of a Memoir on the Natural Laws which appear to regulate the Distribution of the Powers of producing Heat and Light among the different Groups of the Animal Kingdom 241 VI CONTENTS. Page Prof. B. Powell on the Achromatism of the Eye : in reply to some Remarks in the Lond. and Edinb. Phil. Mag. and Journal of Science, No. 33 247 Mr. J. Nixon on the Trigonometrical Height of Ingleborough above the Level of the Sea. Part 1 248 Rev. Baden Powell's Abstract of the essential Principles of M. Cauchy's View of the Undulatory Theory, leading to an Explanation of the Dispersion of Light ; with Remarks {concluded) 262 Rev. J. Challis on the i\.nalytical Determination of the Laws of transmitted Motion 267 Dr. Faraday's Experimental Researches in Electricity. — Eighth Series {continued.) 272 Mr. J. O. Westwood. Insectorum novorum exoticorum (ex Ordine Dipterorum) Descriptiones 280 Mr. D. Griffin on an unusual Affection of the Eye, in which three Images were produced 281 Prof. J. D. Forbes on the Refraction and Polarization of Heat (co7itinued.) 284 Mr. A.Trevelyan's Description of a new Spirit-lamp Furnace 292 New Books : — The West of England Journal of Science and Literature — Mr. Pritchard's List of two Thousand Micro- scopic Objects, &c 293 Proceedings of the Royal Society 297 Astronomical Society 305 Zoological Society 307 Geological Society 312 Preparation of Cantharidine 318 Gallic Acid speedily prepared — Preservation of Deliquescent Salts — Composition of the Atmosphere 319 Meteorological Observations 320 NUMBER XXXV.— MAY. Dr. Daubeny on Dr. Ure*s Paper, in the Philosophical Trans- actions, on the Moira Brine Spring; and on the Proportion of Bromine in the Waters of different Seas 321 Mr. D. Mushet on the Fusion and Appearance of refined and unrefined Copper 324 Prof. T. Graham on Water as a Constituent of Salts. In the Case of Sulphates 327 Dr. Faraday's Experimental Researches in Electricity. — Eighth Series {continued) 334 Prof. J. R. Young on the Summation of slowly converging and diverging Infinite Series 348 Dr. W. C. Henry's Experiments on the Action of Metals in determining Gaseous Combination 354 CONTENTS. Vll Page Prof. J. D. Forbes on the Refraction and Polarization of Heat (concluded,) 366 Proceedings of the Royal Society . „ 371 Geological Society 376 • • Linnsean Society 379 Zoological Society 380 Royal Institution of Great Britain 394 Cambridge Philosophical Society 395 Inquiry respecting the Existence of Provincial Literary and Scientific Institutions — Mr. L. Horner on the Quantity of Solid Matter suspended in the Water of the Rhine 396 Fall of a Meteorite in India, on the 8th of June 1834<-- Queries on some Points connected with the Undulatory Theory, by A Correspondent 398 Detection of Minute Portions of Sulphur— Conversion of Sugar into Formic Acid and Ulmin — Scientific Books 399 Meteorological Observations 400 NUMBER XXXVI.— JUNE. Mr. Beke on the Historical Evidence of the Advance of the Land upon the Sea at the Head of the Persian Gulf; with some brief Remarks on the Gopher-toood of Scripture, in Reply to Mr. Carter 401 Mr. L. Tonna*s Remarks on some curious Facts respecting Vision described in the Lond. and Edinb. Phil. Mag, for 1834 409 Dr. Faraday's Experimental Researches in Electricity. — Eighth Series {concluded,) 410 Mr. R. Addams's Notice of some Experiments which show a repulsive Action between heated Surfaces and certain pul- verulent Bodies 415 Prof. T. Graham on Water as a Constituent of Salts. In the Case of Sulphates (concluded) 417 Notice of the Arrival of Twenty-six of the Summer Birds of Passage in the Neighbourhood of Carlisle,, during the Spring of 1834, to which are added a few Observations on some of the scarcer Birds that have been obtained in the same Vici- nity from the 10th of November 1833 to the 10th of No- vember 1834 424 Mr. E. M. Clarke on certain Optical Effects of the Magnetic Electrical Machine, and on an Apparatus for decomposing Water by its means 427 Mr. J. Nixon's Trigonometrical Height of Ingleborougli above the Level of the Sea. Part II. {concluded) 429 Vlll CONTF,NTS. Page Mr. S. Read on a Decimal System of Monetary Calculation, founded on the present Denominations of Money and Coins in Great Britain , 441 Mr. D. Mushet on the Immersion of Copper for Bolts and Ship- sheathing in Muriatic Acid, as a Test of its Durability .... 4-44 Mr. J. O. Westwood. Insectorum nonnullorum exoticorum (ex Ordine Dipterortim) Descriptiones 447 Proceedings of the Royal Astronomical Society 449 ■ Zoological Society 4-52 Meteorological Observations 468 Index 469 PLATES. I. An Engraving illustrative of Professor Faraday's Eighth Series of Experimental Researches in Electricity — on the Source of the Electricity developed in the Voltaic Battery. II. An Engraving Illustrative of Mr. Nixon's Paper on the Trigonometri- cal Height of Ingleborough above the Level of the Sea. ERRATUM. Page 88, line 20, and page 89, lines 8 and 12, for sec-chd read sup-chd [supplemental chord]. THE LONDON AND EDINBURGH PHILOSOPHICAL MAGAZINE AND JOURNAL OF SCIENCE. [THIRD SERIES.] JANUARY 1835. I. On the Dimorphism of Baryto-calcite. By James F, W. Johnston, Esq., M.A, F.R.S.Ed., F.G,S., Sfc, Reader in Chemistry and Mineralogy in the University of Durham,^ nPHE substance first examined crystallographically and de- -*- scribed as a new mineral species by Mr. Brooke, under the name of Baryto-calcite, is now well known to mineralogists, and is to be ipet with in most cabinets. It has a specific gra- vity of 3°*66, according to Mr. Children, and its form, by the measurements of Mr. Brooke, is an oblique rhombic prism M on M = 106° 51', M on P 102° 54'. Since the discovery of the principle of dimorphism, more particularly since the analysis of the plumbo-calcite enabled me to class the carbonate of lead with that of lime as isodi- morphous bodies, I have looked to this mineral with very considerable interest. If lime, barytes, strontian, and prot- oxide of lead constitute an isomorphous group, of which two are already observed to be c^zmorphous, we may naturally look for a similar property in the other two ; we may expect the carbonates, for example, of barytes and strontian, either in their pure state, or in combination with another carbonate belonging to the same group, to crystallize in two or more in- compatible forms. But the baryto-calcite measured by Mr. Brooke gave us none of that intbrmation we expected from it. The crystalline form was neither that of the carbonate of barytes in its usual form, nor that of the carbonate of lime in calc spar ; it was neither a rhomboid nor a right rhombic * Communicated by the Author. Third Series. Vol. 6. No. 31. Jan. 1835. B 2 Fro^, Johnston on the Dmo?phism of Barylo-calcitc. prism, and yet it bears an analogy to both. It had the oblique character of the one form and the prismatic of the other : it belongs to the hemiprismatic system of Mohs. Since it was first examined and described by Brooke and Children, the baryto-calcite has been found in considerable quantity in several lead-mines in Alston Moor. More recently, however, it has also been met with in other localities ; but ap- parently under different circumstances, and presenting a dif- ferent appearance. The lead-mine of Fallowfield near Hex- ham, in Northumberland, is known to modern collectors of minerals as the locality where the finest specimens of cry- stallized carbonate of barytes have yet been obtained. In this mine a mineral has for some time been met with, crystal- lized in six-sided pyramids, pure white, often transparent, hav- ing occasionally a beautiful pink tinge, and sometimes opake, from an incrustation, apparently of sulphate of barytes. More lately the same mineral has been met with in one of the lead- mines near Alston Moor, presenting the same characters, with the exception of the pink tinge, which I have not observed in any of the specimens I have seen from that locality. These crystals scratch carbonate of barytes and the oblique rhombic baryto-calcite of Brooke; have a specific gravity of 3*76 at 60° Fah., and exhibit the right prismatic form of ar- ragonite and carbonate of barytes. The observation as to the form, which in the present case is the most important pro- perty, has been confirmed by the examination of Professor Miller of Cambridge. Another variety of the same mineral, found at Fallowfield, has a pale cream colour and pearly lustre, and forms some- times masses, more frequently round flattish concretions of the size of a pea and upwards. Viewed through a microscope, these concretions present an aggregation of minute triangular faces, being sides of hexagonal pyramids, similar to those which in the more regularly crystallized specimens sometimes attain nearly half an inch in length. I have analysed both these varieties, and found them to consist of the carbonates of lime and barytes united atom to atom — (C-f Ca) +(C + Ba) — with scarcely a trace of iron and manganese. These crystals have, therefore, the same composition as the oblique rhombic baryto-calcite of Mr. Brooke as determined by Mr. Children. They are, however, of a different form, being right rhombic prisms, and belonging to the proper prismatic system of Mohs, while the oblique rhombic crystals belong to the hemipris- matic system. This mineral, therefore, is dimorphous. There is, however, a peculiarity in the dimorphism of this mineral which has not, I believe, been observed in any other Prof. Johnston 07i the Dimorphism of Baryto-calciie, 3 instance. The ordinary form of the carbonate of barytes is the right rhombic prism. The carbonate of lime in arrago- nite crystallizes in tlie same form ; there is nothing very un- expected, therefore, in a combination of the two assuming the same form. Neither will it be very unexpected when we meet, as we probably hereafter shall, with a similar compound of the two carbonates in the form of the rhomboid in which calc spar ordinarily crystallizes. It will be an interesting fact when observed, but we are in some measure prepared for it by the knowledge of the form and composition of the plumho- calcite. But what is remarkable in the second form of the baryto-calcite is, that it is neither a rhomboid nor a right rhombic prism, though, as I have already stated, it partakes of the characters of both. It is well known that the carbonates of lime, iron, man- ganese, and zinc are only plesiomov)^hous, the oblique angles of their respective rhomboids being 105° 5'— 107° — 107° 20', and 107° 40^ Now, the rhombic base of Mr. Brooke's baryto- calcite is 106° 54'; it is considerably within the limits, there- fore, of the dimensions which these carbonates assume. Is it unlikely that this rhombic base, approaching so nearly to that of rhomboidal carbonate of lime, should be directly derived from it? There are two ways in which we may suppose this oblique rhombic form to arise, or two principles with which we may suppose it to be connected. If we suppose that each of the carbonates is capable of crystallizing when alone^ in the oblique rhombic prism, then we know three incompatible forms of carbonate of lime and two of carbonate of barytes, and we can understand perfectly why they should crystallize together in this form as we find them in the compound mineral in ques- tion. The carbonate of lime also would on this supposition form the connecting link between two isodimorphous groups, being itself /amorphous. Thus, Rhomboid. Right Rhombic Prism. Oblique Rhombic Prism. C+Ca in calc spar. C-fCa in arragonite. C+Ca in oblique C+Pb in plumbo-calcite. C+Pb in carbonate of lead. ^ C-f-Fe in brown spar. C+Fe in junckerite*. C+Ba in witherite. C+Ba in oblique baryto-calcite. But if we suppose that in the oblique baryto-calcite the car- bonate of lime retains its conmion rhomboidal form, as the dimensions of the crystal would at first sight indicate, and *For an account of this interesting mineral, see Ann, deChimie et dePhys.y June 1834, p. 11)8. B2 4 The Rev. P. Keith on the Structure of Animals, that the prismatic form of the witherite has modified it so as to produce a species of hybrid or intermediate form, hav- ing the prismatic character with a less degree of obliquity (102° 54'') than the rhomboid, then it would be unnecessary as yet to consider either the witherite as di-, or the carbonate of lime as ^n-morphous. How far such a combination of the forms is possible, I am not prepared at present to investigate ; it will probably, however, be from the study of the forms of compound minerals, resulting from the union of simple minerals whose forms are known, that we shall arrive at the first general conclusions in regard to the connexion of the forms of che- mical compounds with those of the elements of which they consist. It is not unworthy of remark, that the right rhombic baryto- calcite is harder and heavier than the oblique, a relation similar to that which arragonite bears to the rhomboid of car- bonate of lime. If we take the mean specific gravity of calc spar at 2*65, and that of the witherite at 4*3, and multiply each by their atomic weights, and divide the sum of the pro- ducts by the sum of the weights, we obtain for the specific gravity of a compound of the two, atom to atom, 3'707j rather less than the mineral was found to possess by experiment. In a letter I have just received from Professor Torrey of New York, he mentions a mineral under the name of baryto- strontianite, found in considerable quantity at Kingston, Upper Canada. It is not unlikely that an examination of the forms of this compound mineral might lead to interesting results. Unfortunately, the specimens he sent with the letter have mis- carried. Should this meet his eye, he may, perhaps, find an opportunity of transmitting others. Durham, November 1834. II. Of the Structure of Animals, By the Rev. Patrick Keith, F,L.S. S^c,"^ npHE writer who undertakes to describe the productions of -■- animated nature, whether botanical or zoological, soon finds out the impossibility of examining each individual singly. It would be a labour altogether interminable. But the means of abridging it readily suggests itself; it is that of combining into distinct groups or families all such individuals as are found to exhibit a close resemblance in external form, or in internal constitution, and of designating them under a com- mon appellation. We are led irresistibly to regard them as allied together by nature, and possessed of kindred qualities. • Read before the Hythe Reading Society March 7, 1833; and commu- nicated by the Author. The Rev. P. Keith 07i the Sti'ucture of Animals. 5 This is the generalization that tends so much to the advance- ment of science, and that has, in fact, been made, in a more or in a less philosophical way, by all physiologists from the ear- liest times. We have seen hov^^ it has been done in botany*; let us see how it has been done in zoology. Some, to cut the matter short, go back to Adam, with the beasts, wild and tame, submissively arranged around him-)-, — the tiger playing with the kid, and the lion with the lamb, — and find in the first indi- vidual of the race of men, the first classifier of animals; others go back merely to the period of the Flood, and regard as the first model of zoological classification the arrangements made by Noah in his immense menagerie of the ark \ ; lastly, some are content to begin with Solomon, whom they regard not only, as a botanist, because it is said of him that " he spake of trees, from the cedar that is in Lebanon to the hyssop that springeth out of the wall §," but also as a zoologist, because it is but reasonable to suppose that a writer who said so much about plants, must have said something also about animals. But upon grounds equally valid we might prove that Solomon was like- wise a mineralogist, because he said very truly, as every mine- ralogist must know, that "there is a time to cast away stones, and a time to gather stones together || ." It would be a lame and impotent conclusion, we confess, and therefore we do not venture to draw it. But however this may be, the most ancient model of zoolo- gical arrangement now extant is that which has been left us by Aristotle, the celebrated philosopher of Stagira, and father of natural history. It is founded chiefly on external characters, but it makes a pretty near approach, notwithstanding, to the arrangements of nature. Under a primary division into vi- viparous and oviparous — that is, into such as produce their offspring alive, and such as produce first an egg — animals are distributed, in this arrangement, into four classes, — quadru- peds, birds, fishes, insects. It is somewhat analogous to the botanical arrangement of Theophrastus, borrowed perhaps from his great master, by which he distributes plants into trees, shrubs, undershrubs, and herbs ^, striking, but popular rather than philosophical. Hence many alterations were in- troduced into it by succeeding zoologists, as by Pliny, Gesner, Aldrovandus, but particularly by our countryman Ray, till at last the subject was taken up by Linnaeus, that great reformer of systems, and brought under the scrutiny of his keen and [* See Mr. Keith's papers, on the External Structure of Imperfect Plants, and on the Internal Structure of Plants, Lond. and Edinb. Phil. Mag. vol. iv. p. 252, vol. v. p. 112.— Edit.] f Genesis, ii. 19. % Genesis, vii. 15. § 1 Kings, iv. 33. || Eccles., iii. 5. ^ lis^i (pvTuv imro^txi, to. A. 6 The Rev. V. Keith on the Structure of Animals, penetrating eye. The result was that his arrangements in zoology were adopted and applauded with the same eagerness and universality as his arrangements in botany. He distri- butes animals into six classes, — mammalia, birds, amphibia, fishes, worms, insects*. It was a great improvement upon preceding arrangements, but still it is liable to many objec- tions. Under the honourable and imposing title o^ Primates^ — the nobles of the creation, — it groups together men, mon- keys, and bats, in the same class and in the same order; while it exhibits other incongruities equall}' palpable. But from arrangements founded upon the number of teeth, or of toes, what was to be expected but unnatural associations ? It should be recollected, however, that his arrangements are professedly artificial, and are not to be tried by such rules of criticism as are applicable to arrangements professing to be natural. They have been reformed and improved by Blumenbach -j-, as far, perhaps, as they are capable of improvement; and in their present improved state they may be regarded as making a laudable approximation to the arrangements of nature. The characters of the classes are taken partly from the external structure, and partly from the internal structure. But Cuvier in his Regne Animal, and Carus in his Introduction to the Comparative Anatomy of Animals, have established a new principle of arrangement, and have shown to the satisfaction of zoologists, that all characters of classes truly natural must be taken from the internal structure only, as exhibiting most distinctly the several grades, or several degrees of excellence, that exist among animals, whether as relative to sensation or to locomotion — the very essence of animal ity, and measure of animal perfection. This view may be taken in the order, either of the ascending or of the descending scale, according to the peculiar object of the investigator. Carus adopts the first of the two modes, and ascends from the lowest and mi- nutest animalcule up to man. Cuvier adopts the second of the two modes, and descends from man down to the meanest entity endowed with animal life. His leading and primary divisions, now universally [?] adopted, are the four following |. The first and highest division of the animal scale includes man, and the animals resembling him most nearly in the form and complexity of their internal structure. The leading cha- racter on which it is founded is, that the brain, and the chief trunk of the nervous system, are inclosed in bony coverings the former in the cranium, the latter in the vertehrce, or [joints composing the] back-bone, to the sides of which the ribs, and the bones composing the limbs, which are never more than • Systenm Natura:, 1735. f Manual of Nat. Hist., R. T. Gore. X liegne Animal^ Introcl. The Rev. P. Keith 07t ihe Structure of Animals. 7 four in number, are attached, forming in their ensemble the skeleton or carpentry of the body. Animals of this class are said to be vertebrate, Vertehata. They have red blood ; a muscular heart; a mouth, the origin of the intestinal canal ; two horizontal jaws; distinct organs of sight, smelling, hear- ing, tasting, situated in the cavities of the head ; a generally diffused tact or circumscribed touch ; the locomotive muscles attached to bones ; the viscera lodged in the head and trunk ; the head distinct from the body; and the sexes in separate individuals. Of this general model there are many varieties, the descending gradations of which may very easily be traced from man to the meanest reptile. The second division of the descending animal scale includes the Mollusca, namely, individuals which consist of a soft and gelatinous mass, and exhibit a structure less complex than that of the Vertebrata, The body is without a skeleton, and without a distinct head ; the muscles being attached to the skin, forming a soft and contractile covering, (which in many species is encrusted with a shell), in which envelope the viscera are contained, together with the nervous system, which in these animals takes the form of scattered masses of threads. The chief of these masses lies in [or around] the oesophagus, and is called the brain. Of the senses common to the Vertebrata, they seem to possess only taste and vision ; with the exception of one family — Sepice — which exhibits also organs of hearing. But they have an apparatus for circulation, respiration, di- gestion and secretion, scarcely less complicated than that of the preceding division. The third division of the descending animal scale is that of worms and insects, designated by the appellation of articulated animals, Articidata, exhibiting a structure still less complicated [?] than that of the Mollusca. Their nervous system consists of two cords, extending along the belly, and expanding at regu- lar intervals into knots, ov ganglia. The first of these, placed on the oesophagus, is called the brain, though not much larger than the rest. The covering of the body, in some cases soft, in others hard, is divided by transverse folds into a certain number of rings, with the muscles attached to the interior; and hence their appellation of Articulafa, or, as MacLeay would rather call them, Annulosa *. Many of them have la- teral and articulated limbs, originating in pairs, while others are wholly destitute of limbs. They have not a real circu- lation, except, says Kirby, the Arachnida and Annelida f . They have not lungs, but spiracles. They have organs of * Linn. Trans,, vol. xiv. Part I. [or Phil. Mag. vol. Ixii.pp. 192,255.] f Introd. to Kntomol., vol. iv. p. 80. 8 The Rev. P. Keith o?i the Structure of Aiiimals. taste and of sight, but they have no perceptible or indubitable organs of hearing, with the exception of a single tribe, the Crustacea', and the jaws, if any, are lateral. The fourth and lowest division of the animal scale includes the zoophytes of preceding naturalists, which Cuvier now de- signates by the appellation of radiate animals, lladiata. They exhibit the greatest simplicity of animal structure, and a pe- culiarity of conformation that cannot be mistaken. In the foregoing divisions, the organs of motion and sensation are found to be symmetrically placed on two respective sides of a certain axis. In the zoophytes [and other Radiata,] the corresponding organs are arranged in rays around a common centre, and hence their appellation of radiate*. The subjects of this division approach the homogeneous character of plants. They have no distinct nervous system, nor specific organs of sense, but merely nervous molecules dispersed throughout a gelatinous mass:}:. In a few of them, you may trace some faint vestiges of a circulation, with respiratory organs on the surface of the body. In the polypi, the intestines are a mere bag without passage; and in the infusory animalcula, the lowest in the animal scale, the individual is merely a homogeneous mass of pulp, endowed with motion and feeling. With these divisions in view, we proceed to exhibit a brief and popular sketch, first, of the external structure, and secondly, of the internal structure, of animals. Of the Exteriial Structure of Animals. Division I. The Vertebrata. — Of animals of the division Vertebrata, some are viviparous, and furnished with teats by which they are enabled to suckle their young; this is the class of the Mammalia: some are oviparous, and adapted by their structure to the act of flying ; this is the class of Birds : some are destined to live in water, and adapted by their structure to the act of swimming; this is the class of Fishes: and some are doomed merely to crawl upon the earth, and to pass a great part of their existence in a state of stupor; this is the class of Reptiles. Class 1. If an individual of the class Mammalia is taken and surveyed at the period of its perfect development, it will be found to be composed of a head, a neck, a trunk, and limbs. We will take our view of these parts as they occur in man, who stands incontrovertibly without a rival at the head of the [* It has been shown by Dr. Agassiz, in a paper in our last volume, p. 369, that there is a bilateral symmetry even in certain Radiata^ notwithstand- ing their radiant structure. — Edit.] [f Mr. Keith seems here to confound the organization of all the Radiata with that of one of the groups referred to them by Cuvier : in the Starfish and Echini, for example, there is a distinct radiant nervous system. — Edit.] Vertehrata — Man. 9 animal creation, not merely as the first in the first rank, but as constituting an order of himself, into which no other genus is worthy of being admitted, and as exhibiting a fabric that we cannot but regard as the most perfect model of animal or- ganization. In surveying this model, the first thing that arrests our at- tention is that most remarkable and striking peculiarity con- nected with, and dependent upon, structure, by which man is at one glance distinguished from all other animals whatever, and elevated, as it were, on an eminence which they can never attain, namely, that of his upright or erect posture, through means of which, while other animals look prone upon the ground, we raise our face to heaven, to contemplate the throne of God. Ovid, the sweetest of Latin poets, has de- scribed this distinguishing attribute of man in language pecu- liarly felicitous : Pronaqne cum spectant animaiia caetera terrain Os honiini sublime dedit, coelumque tueri Jussit, et erectos ad sidera tollere vultus. — Metam, i. Milton also, the loftiest and most sublime of British bards, whose epic rank and dignity is second only to that of Homer and of Virgil, has been equally felicitous with Ovid in his de- scription of the dignity of the human form : Two of far nobler shape, erect and tall, God-like erect, with native honour crowned. In naked majesty, seemed lord.s of all. Paradise Lost, book iv. Of this noble and dignified structure, the portion that claims our first notice is the head, the capital that crowns the fabric. Its elevated position ; its ample expansion of countenance, — the index of the operations of mind ; its rounded and globular form ; its comely covering of hair, hanging in the unadorned simplicity of nature, or modified by the contrivances of art; and its serving as the seat of almost all the organs of sense; are prerogatives that entitle it to our peculiar consideration. If we look at its elevated position, we shall find that the head assumes, as it were, the post of honour, being placed above all the other portions of the fabric, and hence giving the necessary elevation to the organs with which it is fur- nished, particularly to the organs of vision, by which we can thus command a wider and more extended view of the glories of external nature. Had man been destined to walk or to stand on all-fours, as some philosophers have presumed that he originally was, he would have been in a worse predicament than even any of the quadrupeds, whose look, though prone, Third Series, Vol. 6. No. 31. Jan, 1835. C 10 The Rev. P. Keith on the Structure of Aiiimals. is still well adapted to their form and condition ; for in that case his face would have been depressed to a parallel with, or even to an angle beyond, the level of the horizon, and his look turned neither forwards nor backwards, nor to the one side, but directly downwards. ' It could not then have been said that he was made to contemplate the heavens. But the ine- quality that is so notoriously evident in the length of our legs and arms, together with their mode of articulation and flexure, aftbrds proof sufficient that nature never intended man either to walk or stand except upon his feet only, and that, partly at least, for the purpose of giving elevation to the head. If we look at its expansion of countenance, we shall find that the head most nobly vindicates its preeminence over all the other portions of the human fabric, and conspicuously exalts the dignity of man. The amplitude of the forehead ; the ex- pression of the eyebrow; the fire and brilliancy of the eye; the bold and manly, or the delicate and feminine, profile of the nose ; the blush and dimple of the cheek ; the witchery of the smile; and the lovely contour of the chin; are attributes of man's countenance that are palpable to every one, and are the perpetual theme of the admiration, whether of the lover or of the philosopher. To this we ought also to add that inter- minable diversity of feature and of lineament so remarkable in the human face, that out of the countless millions of man- kind possessing all that closeness of resemblance and all that striking similitude of form that are necessary to determine the species, or even the variety, no two individuals have ever yet been found so exactly alike as to make it a matter of any great difficulty to distinguish the one from the other. Philosophers reduce the peculiar traits of countenance t!:at characterize the several races of mankind to certain manifest varieties, of which the following are the most important: 1st, The Caucasian, whence the European variety : countenance oval; features delicately blended ; forehead high and broad; nose aquiline ; cheek-bones not prominent ; complexion fair. 2nd, The Mongolian variety : face broad and flat ; nose flat ; space between the eyes wide; chin prominent; complexion olive. 3rd, The American variety : visage broad, but not flat; cheek-bones prominent; forehead short; eyes deeply fixed; nose flattish, but prominent; countenance red or of a copper tint. 4th, I'he Negro variety : face narrow, projecting in the lower part; forehead narrow, retreating, arched; eyes pro- minent; nose and lips thick; complexion black. 5th, The Ma- lay variety : face not so narrow as in the Negro, projecting downwards; nose bottled ; mouth large ; complexion tawny*. * Bkimenbach*s Fhi/s., by Elliotson, p. 391. Vertebraia—Man, 11 If we look at its rounded and globular form, we shall per- ceive that the human head has a grace and beauty conferred upon it that do not belong to any other form peculiar to any other animal ; and even in man, the varieties having most of the globular form have the most of beauty. This will appear very plainly, if the investigator will take the trouble to com- pare the form of the Caucasian variety with that of the other four varieties, either in the actual crania of dissected subjects, if he has access to such, or in the drawings with which anato- mists have furnished us. The head of the Georgian female is regarded, by Europeans at least, as the most perfect model of human beauty. It is the most globular of all the varieties, and is generally quoted as an example of the most exquisite of capital forms. In the other varieties, but particularly in that of the Negro, the forehead is so much flattened, and the lower part of the face — the mouth and jaws — so much protruded, as to suggest the degrading idea of a snout or muzzle; lowering, in our estimation, excessively, the pretensions of the Negro head, whether to grace or to beauty. Physiologists have even instituted a standard of perfection with regard to the form of the head, which they find in the facial angle of the Caucasian variety. Viewing the head in profile, when the body stands erect, draw a line from the greatest projection of the forehead to the upper maxillary bone: this is the facial line. From beneath the basis of the nostrils, draw a horizontal line meet- ing the facial line: this junction gives the facial angle*, and the measure of the relative projection of the jaws and fore- head. The nearer it approaches to a right angle, or in other words, the less prominent the jaw, the more perfect is the form, and the greater the presumed sagacity of the individual. But if the head of the Negro will not bear a comparison with that of the Caucasian, much less will the head of any of the inferior animals bear it. If we look at its comely covering of hair, we shall find in that feature also another source of beauty. Among Europeans, Eastern Asiatics, and Northern Africans, the hair of the head ^rows to a great length, particularly in females. We have known it to exceed the length of three feetf. Its colour is black, brown, or red, according to climate, or to other con- tingencies. On the fore part of the head it falls towards the brow, on the back part towards the neck, and on the sides towards the shoulders. It is very ornamental, and admits of * Blumenbach, by Elliotson, p. 388. [f Authentic cases, we believe, are upon record, in which the hair had attained a much greater length. — Edit.] C2 12 The Rev. P. Keith on the Structure of Animals, being done up in a great variety of ways, so as to please all tastes and all fancies : — Cmflavam religa5 comam. Simplex munditiis? — Hon., lib. i. ode v. Yet sometimes crops are the fashion, and sometimes wigs; but nobody chooses a red wig, as I believe. There seems, in- deed, to be a prejudice against red hair in any shape what- ever. It is alleged, but how truly I cannot say, to have some intimate connexion with the temperament of the body, causing a fetid and disagreeable odour. In man, black hair is sup- posed to be expressive of strength; in woman, of vivacity : whilst in woman, the blond is thought to be expressive of delicacy, and in man, of I know not what, that is devoted to pleasure. So says Bichat*. The beard is peculiar to males. Christians shave it; Jews suffer it to grow. It appears at the age of puberty, of which it is a sign. It is shorter than the hair of the head, as well as more given to curl, and its colour is generally either black or red. Lastly, if we regard the head as being the seat of the organs of sense, we shall find its preeminence above all the other parts of the human fabric to be most signally demonstrated. First, as containing the eye, the organ of vision, which, sta- tioned like the sentinel in his watch-tower, surveys from its lofty height the objects placed around it, and unfolds to the individual the beauties of the external world. Cicero seems to have been duly impressed with a conviction of this truth when he wrote the following sentence : " Nam occult tanquam speculatores, altissimujn locum ohtinent, ex quo plurima conspi- cientes, funguntur suo munere\f — 'For thus the eyes, placed like sentinels on a watch-tower, discharge their function with an extended sphere of vision.' Secondly, as containing the ear, the organ of hearing, calculated to receive the impres- sions of sound, to give us notice of the approach of external objects, and to enable us to appreciate the value of tones, whether they be the modulations of music, or the articulations of a spoken language. Thirdly, as containing the nose, the organ of smell, and source of balmy delights, projecting, as Haller observes, " like an engine in the air J," to arrest and collect the perfumes, sweets, and odours that are exhaled from the treasures of Flora, and wafted on the winds. Fourth- ly, as containing the tongue, the organ of taste, and with the mouth the arbiter of savours, discriminating between the clean and the unclean, the noxious and the wholesome, the produc- * Anal. Gen. Si/st. Dermoid. f De Nat. JJeur. J First Lines, by Cullcii, sect. 465. Vertebrata-^Man, 13 tion that is good for food and the production that is to be re- jected ; as well as forming a principal part of the apparatus of speech, the distinguishing attribute of man. Fifthly, as pos- sessing in common with all the rest of the surface of the fabric the general attribute of tact, which exists, however, in the highest degree only in the palms of the hands and at the ends of the fingers, and is there denominated touch. Finally, be- sides being the seat of the organs of sense, it is also the seat of the endowment of intellect, as is indicated by our own inter- nal convictions, leading us irresistibly to the conclusion that thought has its residence in the head. The head thinks. The second portion of the fabric of the human body is the neck, which we may regard as the shaft or column that sup- ports the grand and Corinthian capital of the head, in the base of which it originates. In man it assumes a circular and co- lumnar form, possessing great natural grace and beauty. Anacreon exhibits a fine idea of its fascination in his direc- tions to the artist who was about to take the portrait of his female friend : Tpv(psp8 S' s(TU3 ysvsis Uspl Xvy^ivM rpdyriK^ Xdpirss TfsTOiyr'j irxcrai, — Ode xxviii. * Under her beautiful chin, around her snowy neck, let all the Graces be fluttering.' The description was no doubt suggested by the original from which he drew. But, in addition to its native loveliness, the neck admits also of such artificial orna- ments as may be suggested by the fertile fancy of the arbi- tresses of female fashion. " Thy cheeks are comely with rows of jewels; thy /i^c^ with chains of gold *." So said the wisest of men. It possesses, besides, a peculiar flexibility, by which the movements of the head are multiplied and facilitated ex- tremely, as well as rendered peculiarly elegant and expressive. Tapering delicately towards the middle, it begins again to ex- pand, till it ultimately rests upon the shoulders, and forms the connecting link between the head and the trunk. In quadru- peds, though it does not always assume the circular form, still it possesses much beauty, as in the case of the horse. " Hast thou given the horse strength ; hast thou clothed his neck with thunder f ? " The third portion of the fabric is the trunk, which we may regard as the base or pedestal that gives bulk and stability to the individual, with support and attachment to the neck and head, as well as to the several limbs. It is divided super-, ficially into certain peculiar regions, — the back, the sides, the shoulders, the breast, the abdomen. The greatest bulk of cir- * Canticles, i. 10. f Job, xxxix. 19. 14 The Rev. P. Keith on the Structure of Animals, cumference of the body lies within a line encircling the breast; but in a high state of corpulency, or embonpoint, the greatest circumference may lie within a line encircling the abdomen, as in the case of Falstaff's waist, according to Shakspeare; " Fat, My honest lads, I will tell you what I am about '* Pist, Two yards and more. " Fal, No quips now. Pistol ; indeed I am in the waist two yards about, but I am now about no waste. I am about thrift *." — A rare thing for Falstaff to be about, and worthy of special notice ! In the body, as also in the head and neck, you may readily trace a medial line, having similar parts or organs on each side, on the right and on the left, — the two eyes, the two nostrils, the two ears, the two shoulders, the two breasts, the two sides. The medial line of the trunk is displayed most conspicuously in the back, following the course of the backbone, and in most of the Mammalia terminating in a tail, of which men and some monkeys are destitute. In men the surface is covered with a naked skin, which gives the body a quick and susceptible tact throughout, but requires the aid of clothing. The fourth and last portion of the fabric is that of the limbs. In the Mammalia, and indeed in all vertebrate animals, where limbs are present, they are almost always four in num- ber; and upon the principle of duality, and of a right and left side, which we have just recognised, they go in pairs, — two fore limbs, and two hind limbs. In man the two fore limbs are composed of the arms, the fore arms, and the hands. The arms extend from the shoulder to the elbow, the fore arms from the elbow to the wrist, and the hands from the wrist to the tips of the fingers. Each hand is composed of a metacarpus, or body, which constitutes what we call the back and hollow of the hand, together with four fingers and a thumb, the thumb being so placed as to stand in opposition to the fingers, and thus greatly to facilitate the grasping or holding of small bodies. The palms of the hands, and particularly the ends of the fin- gers, are the peculiar seat of touch ; to which the nail, placed only on the one side of the extremity, affords a kind of sup- port. No other animal possesses an organ of touch so perfect as that of man. The hand of apes makes the nearest approach to it, but is far from reaching to its perfection of form. Even the hand of the ourang-outang, the most perfect of apes, is too long in proportion to its width, and the thumb, which scarcely reaches to the root-joint of the forefingerf, too short, and too ♦ Merry Wives of Windsor, Act I. Sc. 3. t Dr. Abel. Griffith's Suppl. Hist, of Man. [On the hand of the ourang- outang, see also Dr. Jeffi-ies's paper in Phil. Mag. vol. Ixvii. p. 183, 188. — Edit.J Vertehrata — Man, 15 inefficient, and too little suited to be put in opposition to the fingers, to bear a comparison with that of man. The two hinder limbs are composed of the thighs, the legs, and the feet. The thighs extend from the hip to the knee, the legs from the knee to the ancle, and the feet from the ancle to the tips of the toes. Each foot is composed of a imtatarsus^ or body, constituting what we call the back and sole of the foot, which terminates in five toes, — the great toe, the little toe, and the three middle toes, — all placed upon the same level, so that the great toe cannot be opposed to the other toes, as the thumb is opposed to the fingers of the hand; a conformation evi- dently in keeping with the erect posture proper to man, as being calculated to enable him to stand or to walk firmly on the soles of his feet, and to leave his hands and arms at li- berty ; whereas the hinder limbs of apes may be said to end in hands rather than in feet, and to have palms and prehensile fingers rather than soles and toes, which, when placed upon the ground, rest, not on a broad and flat surface, like the sole of the human foot, but merely on the exterior edge of the or- gan, and hence present no proper basis of support to uphold the fabric in an upright position. Thus man is the only two- Imnded animal that exists j for apes are in fact four-handed, as the foregoing detail exhibits them, and are hence duly en- titled to the epithet Quadrumana^, by which they are now de- signated, and by which the difficulty that puzzled Linnaeus has been at length overcome : " Nullam characterem hactenus eruere potui, Jtnde Homo a Simla internoscatur\ f — ' I have hitherto been able to discover no mark by which men may be distinguished from monkeys.' If other proofs were wanting to show the superiority of men to monkeys, it would be easy to adduce them. They are de- stitute of speech ; they are destitute of intellect. What is this owing to ? Camper, who dissected an ourang-outang, found in the front part of the neck two bags, or cavities, communi- cating with the trachea, which seemed to him to be incom- patible with distinct articulation J. After all, it is doubtful whether the bags in question form an absolute bar to speech. Mr. Lawrence thinks they do not, and regards the total inca- pability of apes to generalize their ideas, or to pursue a conse- cutive train of thought, as being the only true bar that lies be- tween them and speech. Thus the grand cause of their inability to form a spoken or articulate language is placed beyond the reach of anatomical detection, and is apparently owing to their want of intellect. Sir Charles Bell regards their inability to * Cuvier, Regne Anim., Mamiiial. f Quoted by Blumenbach. : Griffith's Suppl. Hist, of Man, i. 235. [See also Dr. Jeffnes*s paper, uhi sup., p. 184, 185. — Edit.] 16 Prof. Poweirs Abstract o/M, Cauchy's articulate as resulting not merely from want of intellect, but from want of due organization also*, or of the due comple- ment of nerves necessary to associate the several organs in one act of vocal ity. Why they are destitute of intellect, though furnished with an organization approaching to that of man, it is not our present business to inquire ; but facts show that they are so. How, else, are they so totally incapable of education ? The ourang-outang and chimpanse have even been admitted into human society, by way of experiment, but they have shown no disposition to adopt the haliits and manners of men ; and though capable of imitation in some things, they can never be taught to imitate the articulate tones of the human voice. Besides, they have no relish for the society of men ; and remain, even in the midst of mirth, " for ever silent and for ever sad." Hence, though we may fairly say of them, " Mefis agitat molem f," yet we cannot say that it is the " mens divifiior' which is proper to man. In quadrupeds the feet are four in number, as the name im- ports. They are single and undivided, as in the horse ; or they are divided into toes, of which some genera have two, as the ox and goat ; and some more than two, as the hog and elephant, which last has five fingers inclosed within the skin of the foot; while others have the toes united by means of an intervening membrane, and have hence obtained the appella- tion of web-footed, as in the case of the seal and otter. Yet the limbs of quadrupeds, upon the whole, whether anterior or pos- terior, will be found to exhibit a striking analogy to the type of man, if we look at and compare the same joints. [To be continued.] III. An Abstract of the essential Principles of M. Cauchy^s View of the Undulatory Theory^ leading to an Explanation of the Dispersion of Light ; with Remarks. By the Rev. Baden Powell, M.A,j+AC3/ + >3), [2 + ?+ A(2+?) whilst for r, we have r (1 +e) and its projections A J7 + A f , A j/ +A>), Az+A? and (substituting from (2.) the values of Ax, &c.) r^(l + ef = (r cos «+ A^T-\-{r cos /3+ Arif + (rcosy+A?)^ (6.) Again, the cosines of the angles which the line joining m m forms with the axes, will no longer have the values (2.), but at the end of the time t will be represented by A^ + Ag _ cosa + ^- ^(1+0 A7/-hAYI r{i+e) Az+AK r{i-\-e) 1-f-f 1+. ' cos(3+^- (l + «) ' cosy 4--^- (7.) View of the Undulatory Theory of Light. 23 In this case also the moving force will have for its projec- tions, expressions analogous to those before given (l.), which will be AS r cosa + - - , ^, "1 m f cos 13 + -- ^ 1 mSU ____JLf(r(l+s))J r cosy + ~- 1 ^S|.. --^?;^f(r(l+e))j (8. For abbreviation, let us assume a function /(r) such that we have l(!_(i±!)) = a/(r)+fW (9.) Also, by supposition, Af, &c., and s are very small quan- tities, so that terms of these quantities of two dimensions may be neglected. Combining this consideration with that of the equations (5.), we shall see that two terms will disappear from the coefficients of m in (8.) when expanded by introducing the value (9.)? or those coemcients will take the form S |m ^Afj+ S{m/(r)ecosa} S4m-^A>)|H-S {mf{r) e cos /3} (10.) S ^m ~ A^\+ S {mf{r) s cos y}. Again, from equation (6.)? on the same supposition of neg- lecting the powers above the 1st, we shall have a value of e which will be, 6 = — (cosaAf + cos/3A>j + cosyA? (11.) But the coefficients of m represent the accelerative force which solicits the molecule m due to the action of the molecules ?», m', ?w", &c. On the other hand, by the principles of dy- namics, these accelerative forces parallel to the three axes will be expressed by the second differential coefficients of ^, >j, ^, related to the variable t. If, then, we take the simpli- fied expressions (10.), and introduce the value of s (ll.)> we shall finally obtain the expressions 24 Prof. Powell o« the Undulatoty TTieorij of Light. ~dt^ ~ 1 L f {r) -\- cos^ uf {r 4 cosa cos j3,/(r) "\ cos a cosyf(r) An A? S{^ cos^cos«/(>) ^^1^ cos /3 cos yf[r) + s r cospcosy/jr) ^^1 (12.) s^^ co^yc°^«./W ^jj fLi= J + S L + S { { cosy COS ^f{r) f(r) + cos^y/(r) These are the differential equations, which will represent the motion of a system of molecules which, being subject to the action of mutual attractive or repulsive forces, are slightly disturbed from the positions which they occupy in the state of equilibrium of the system. These equations are those before alluded to as being, in fact, the same which M. Cauchy has established in the me- moir in his third volume. In the subsequent investigation in the fourth and fifth volumes, he at length deduces the well- known partial differential equation for vibrations (a being the rectilinear displacement of a molecule and s a constant) d^8 = 5^ and from the form of its integral he establishes the laws of the propagation of the plane waves. The celebrity of the discussions relative to this formula carried on by Euler and D'Alembert (Berlin Acts 1747), and decided by La Grange (Turin Memoirs 1759), as well as Dr. Charles J. B. Williams o?i Sound. 25 the important considerations involved in the solution, are well known to mathematicians. But it may not be useless for the student to bear in mind the connexion between the form of the function in its integra- tion and the principle of the superposition of small motions arising from the circumstance of the linearity of the expression (in which case alone the differential coefficient of a sum of functions is the same as the sum of the differential coeffi- cients). This point will be found illustrated in the particular view which M. Cauchy takes of the subject. In his memoirs " On the Dispersion," &c., having esta- blished the above equations of motion (12.), he pursues from this point a different course to that adopted in his former me- moirs ; and from certain considerations which he lays down relative to the method of integration in this case, he is enabled to deduce expressions, from which not only are all the laws of the propagation of waves deducible as before, but also the other important relations to which we have alluded established. [To be continued.] IV. Observations on the Production and Propagation of Sound, By Charles J. B. Williams, M.D,, SrC^ TT is rather singular that so simple and comparatively easy -^ a science as acoustics should have been so tardily de- veloped, and that much of its recent advancement should be referrible rather to the illustrations which it affords to the sister science, optics, than to its own intrinsic value. So true is it that sight is our predominant sense, and that dark- ness and ignorance have become synonymous terms. Can it be a matter of wonder or of complaint that the organization of the ear is still involved in mystery, when so much of the laws of sound, to which it is doubtless adapted, is unap- preciated or unexplained ? We would venture to hope that some master-spirit will take up the subject of acoustics, not only as an interesting and instructive link between the me- chanical sciences and those subtler ones of light, heat, and electricity, but also for its own sake, and for the support and improvement of those useful and agreeable relations to social happiness which depend on the perfect state of the sense of hearing. In the mean time I venture to bring before the [* Communicated by the Author. — The substance of this paper was read before the Section of Mathematics and General Physics of the British As- sociation, at the Meeting at Edinburgh in September 1834 : see our last volume, p. 387.] Third Series. Vol. 6. No. 31. Jan. 1835, E 26 Dr. Charles J. B. Williams on the Production Association an attempt to give a greater precision to our ideas on this subject, in a few considerations which have re- sulted from the study of acoustics in connexion with its appli- cation to the distinction of diseases ; and until they shall be confirmed by more competent authorities, I would advance the following remarks as inquiries, rather than as absolute assertions. I. On the Nature and Transfer qfsonm'ous Vibrations. 1 . It is generally said in works on acoustics, that solids are good conductors of sound; but this expression requires quali- fication, for the power of bodies to transmit sound is not ab- solute, like the properties of conducting heat or electricity, but relative to the matter and form of the body from which the sound directly proceeds. Thus, the ticking of a watch is transferred to the ear perfectly through the longest piece of timber, but the sound of the voice or of a flute passes much more readily through the air*. As this subject is one of great importance in practical acoustics, and as it does not appear to have been developed to the extent of which it is capable, I may be permitted to enter a little minutely into the nature and progress of the motions constituting sound in various bodies. t2. All matter is susceptible of sonorous vibrations, and as a general rule, it may be stated that this susceptibility or ca- pacity is in proportion to the strength and uniformity of the molecular elasticity in the matter. By molecular elasticity is meant that force by which the molecules of a body are held at a certain distance from each other, and resist any effort to displace them from it. Thus, glass and steel may be said to possess molecular elasticity in a powerful degree, because any external impulse is instantaneously communicated from par- ticle to particle throughout their whole mass, and it is not lost or broken by the yielding or displacement of the molecules at the point struck. Air and other fluids, on the other hand, cannot be readily thrown into vibrations, unless the impulse be very forcible, or applied to some extent of surface, by which it becomes communicated to many particles at once. 3. Sound has been defined by Dr. Young and others, as * Thu« in Mr. Wheatstone*8 beautiful experiments with the " Enchanted Lyre" he could not succeed in transmitting, by any contrivancey the sound of the voice or a flute through a solid conductor without very great loss in the intensity of the sound; whereas the notes of solid cords or wires passed so little inipaired by the transfer as to produce the magical effects of the in- strument just mentioned. (See the last Numbers of the Journal of the Royal Institution.) It is hoped that the succeeding remarks in the text will explain the causes of these differences. and Propagation of Sound. 27 motion of a certain velocity* ; but it is not simply this, for the velocity of wind, which is much greater than that of most initial soniferous impulses, does not suffice to produce sound, unless it meets with an obstacle; and certainly the movements of the earth and the heavenly bodies should, according to this definition, develop sound, and realize the poetic idea of " the music of the spheres." A more exact physical definition would be, motion of a certain velocity resisted with a certain force. The moving and the resisting forces, acting in op- posite ways, constitute the vibrations of sound f . 4. The motion of matter producing sound should be consi- dered as molecular, although the result is the motion of a mass. Let it be represented thus : an impulse being im- pinged on certain molecules, momentarily overcomes the re- sistance of their inertia, and causes them to start from their place; that force of repulsion which, existing between the dif- ferent molecules, more or less strongly resists the attempt to approximate them, transfers the impulse from molecule to molecule, and thus extends it throughout the mass. The im- pulse that forced these molecules from their position being overcome by the reaction of the elastic forces, (attractive and repulsive,) these forces drive them back to beyond their pro- per station, whence, from the same "cause, they again spring, until by a series of these alternating vibratory motions, the disturbing force is lostf. The assimilating or propagating power, then, of these vibrations depends on the repulsive and attractive forces (2.) of the molecules of the vibrating matter, and in proportion as these are strong to resist or react on a mechanical impulse, they will convert that impulse into a sonorous vibration (3.). 5. Uniformity or equality of molecular elasticity (2.) is * *' It appears that the only condition necessary for the production of a simple sound is a sufficient degree of velocity in the motion or impulse which occasions it." — Dr. Youngs Lectures^ vol. i. p. 378. Dr. Young here considered sound in a physiological sense. The paragraphs 2, 4 and 5, appeared in a chapter on Sound prefixed to my " Rational Exposition of Physical Signs," Scc^published in 1828, some years before Sir John Herschel's articles in the Encyclopcsdia MetropoUtana and Philosophical Magazine re- ferred to in the Editors' notes below. [ t Sir John F. W. Herschel's implied definition {Encycl. Metrop., Essay on Sound, art. 138,) is as follows: *' Every impulse mechanically communi- cated to the air, or other sonorous medium, is propagated onward by its elasticity as a wave or pulse ; but, in order that it shall affect the ear as an audible sound, a certain force and suddenness is necessary :" this, we appre- hend, is virtually the same with Dr. Williams's definition in the text. — Edit.] [X Illustrations of this subject will be found in Sir John F. W. Herschel's paper on the Absorption of Light by Coloured Media, Lond. and Edinb. Phil. Mag., vol. iii. p. 403— 404.— Edit.] E2 28 Dr. Charles J. B. Williams oti the Production equally necessary for the production and propagation of so- norous vibrations ; for if the elasticity of some molecules be less than that of others, the reaction, being less prompt (4.), will produce vibrations not consentaneous with those of the others, and may impair or even destroy them, and this the more effectually the more irregular and varied these mo- tions are. Hence in bodies of mixed density the vibrations do not continue, and the sound heard is only a stroke or knock. Now, to understand more clearly the relative power of dif- ferent conductors with regard to sound, we will take in con- trast the relations of two, which differ greatly, steel and air. 6. When a piece of the former, freely suspended, is struck, the impulse is propagated through the particles in the manner just described (4.), until it is expended in forcing them into an excursion at the opposite surface : then, their elasticity coming into play will determine their recoil with a similar excursion on the other surface, and then back again, until the disturb- ing force is lost by friction, &c.* The continuance of the vibrations and the production of a tone are here independent of surrounding bodies. In air, on the other hand, one ele- ment of molecular elasticity (2. 4.), attraction, is wanting; hence, after an impulse has been applied to a body of it, this fails to produce a continued tone without the aid of reflecting walls of some denser matter. 7. Another remarkable difference between air and a sono- rous solid is, that tones of volumes of the former become deeper in proportion to their size; whilst, up to a certain limit, enlarging the bodies of solids increases the rapidity of their vibrations, and therefore heightens their tones. The cause of this difference has been sufficiently investigated with regard to air ; but although the fact is familiar, I have not met with a close examination of the cause of the lowering the tone of a solid by reducing its thickness. The greater proportional re- sistance of the air is not a sufficient reason, for the tone is nearly as much diminished in vacuo ; and the diminished in- ertia of the thinner body would probably be enough to coun- terbalance this influence. The true cause I believe to be, that in solids of small thickness the impulse is not expended on reaching the opposite surface with the vibration proper to the material ; hence the impulse continues to operate, and forces the particles into an increased and therefore prolonged excur- sion (6.), which, by causing further condensation, augments their elastic force, and enables them to overcome the impulse. • See Sir John Ilerschei's paper on Absorption, as just referred to. — Edit.] and Propagation of Sound, 29 The mass is thus, by the superiority of the impulse over the com- bined normal resistance oi'the molecules of its diameter (6.)j brought under a new law, from which it derives its altered tones. If the impulse be infinite, this law will find its limit in masses of the thickness of a vibration or wave of sound in the matter, which of course varies with its compressibility: in greater lengths, the impulse being efficiently reacted on by the proper elasticity of the material, and not continuing long enough to increase the sphere of the vibration, passes on as a wave, alter- nated with a counter-wave of reaction (3.). Such is the case with the longitudinal vibrations of rods, as illustrated by Chladni; and the law is fundamental to all the various simple sounds of solid bars, balls, plates, bells, and even wires and cords, the molecular elasticity being brought in these last into uniform force by extraneous tension. It would be endless to follow it through its extensive relations ; but it may be noticed that one of the applications of the preceding view is to explain how (by increasing its excursions (T.)?) thinning or beating out a mass of metal augments its power of impressing the air to a degree far greater than the reason usually assigned, increased contact, could account for. 8. Air is a bad conductor of the vibrations of solids, and solids are much worse conductors of the vibrations of air than air itself. The very different molecular elasticity (2. and 4.) of these two classes of matter is the obvious reason of this. Thus, a pulse of air coming against a hard surface, instead of over- coming the inertia of its molecules, so as to extend the vibra- tion through the solid mass (4.), is first condensed, and then recoiling back by its own elasticity, constitutes an echo. The vibrations of a dense solid, on the other hand, as they are strong by the sturdy elasticity of the molecules (2. and 4.), so for the same reason, unless the impulse be very powerful in pro- portion to the mass, they are limited in their excursions. They, therefore, produce but minute vibrations in air, which being much less strongly elastic, requires longer pulses for a similar effect ; and many direct vibrations are thus lost hy the noise- less yielding (3.) of the air; oblique ones, by irregular refrac- tion in passing into a medium of different density ; and the few that are transferred are too weak to extend far. 9. The best mode of overcoming the difficulty of the trans- fer of vibrations from one medium to another is an interesting point, as it includes the principle of sounding-boards of musi- cal instruments. We have already noticed that thinning a sonorous solid increases the sphere of its vibrations (?.)> and therefore their power of affecting the air (8.) ; and provided that attention be paid to the direction of the vibrations, a similar 30 Dr. Charles J. B. Williams on the Production effect is obtained by connecting the sonorous solid, a tuning- fork, for instance, with an extended surface of thin metal of the same elasticity (2.). Such a metallic sounding-board greatly increases the sound, and to the ear applied on it, does so as much as a wooden one; but it is greatly inferior to this in extent of excursive vibration, and consequently in the volume of sound which it sends through the air (8.) ; besides which it is capable of producing sounds of its own that injure the purity of the original note. The superior power of wood in this respect, as the medium of transfer, will now be sufficiently clear. According to the experiments of Chladni, finely fibred fir-wood conducts sound along its fibres with nearly the same facility and velocity as steel. Such great molecular elasti- city (2.) enables it to receive the slightest or most rapid vi- brations uniformly from a vibrating solid, whilst from its light- ness or small inertia (4.) these become sufficiently excursive to take full effect on the air, (8.) ; and no new or interfering sounds can be produced in the wood itself, because its want of uniform density across the grain would absorb or destroy any vibrations in a direction different from those of the sono- rous bar or cord communicating with it. Messrs. Savart and Wheatstone have well illustrated the influence of the form and position of sounding-boards, with their effect of producing within themselves, and with the contained air, vibrating sy- stems ; but their material appears to have been in great mea- sure overlooked. Examining the matter elementarily, we are led to point out rigidity of loiigitudinal fbre, by which the vibrations are equally and perfectly received from a sounding cord or bar (2. and 8.) and lightness ofmass^ by which they are made excursive and freely transferred to the air (4. and 7.), as the two most essential qualities for the materials of sound- ing-boards. These conclusions are quite in accordance with the experience of musical instrument makers, and, perhaps, may be useful in making this experience more rational and certain. The same properties render light rigid wood a gobd material for stethoscopes, which are intended to convey sounds of various media in the most direct way to the ear. II. On the Sounds of single and repeated Strokes. 10. Single blows, such as those of a hammer on a nail or stone, are considered by Dr. Young and Sir John Herschel to consist of a single impulse (4. and 6.), and not of succesive vi- brations, and therefore to have no pitch. Hence they de- scribe a succession of these, as in the striking of the teeth of a cog-wheel against an object, as capable of producing musical tones in the same way and at the same ratio as the vibrations and Propagation of Sound. 81 of a cord. But although rapid revolutions of such awheel, so as to make above 100 or 150 strokes in a second, do pass into continuous tones which can be referred to a particular pitch in the musical scale, yet the slower rotations do not pro- duce a bass note, as an equal number of the vibrations of a cord, but only a succession of distinct clicks. This shows, I think, that the single clicks have a pitch, and that this is at the point where their succession begins to form a continued tone*. 11. That single strokes have a pitch, and consist of at least two vibrations (" semi- vibrations," Wheatstone), is further ap- parent to an ear accustomed to distinguish between musical notes, when they are made with different degrees of force : the gentle strokes are obviously lower than the forcible ones. The cause of this curious fact seems to be, that a forcible im- pulse, by momentarily increasing the density, accelerates the vibration. So also a very violent blow on a bell or bar, or a forcible pull of a cord, will make the initial vibrations quicker, and therefore the tone sharper, than in the proper note. This is perceptible in the loud notes of the harp : but the less yielding tension of metallic wires makes them still more liable to this change of tone ; it is therefore most obvious in the twang of those instruments with wires, which are acted on by points projecting from a revolving barrel. 12. With the exception of this effect of force (14.), the note of continued sounds resulting from a rapid succession of strokes, which for convenience may be called click sounds, de- pends entirely on the frequency of these strokes (10.). In bodies of no given tension, this rapidity is most indeterminate and irregular ; but in cords or bodies of a fixed key, when the series of impulses surpasses in rapidity the vibrations of the fundamental note, they will pass into its upper octave, or others of its higher harmonics. This is one reason why the bass cords of a violoncello, when bowed by an unskilful hand, give out various high and mixed notes, instead of the pure rich bass which those elicit who have experimentally acquired a mastery over the vibrations of the instrument. 13. Click sounds (10. and 12.) in bodies of no given ten- • In attempting to excite a continued note as low as possible, M. Savart was obliged to abandon his toothed wheel, and use one with long vanes, which, by passing close to, but not touching, a lamina of pasteboard, pro- duced in the air a series of concussions, which, if of a certain frequency, be- came a continued note. It is plain that the pitch of the single strokes here was exceedingly low, for the wheel was nearly five feet in diameter, and with this a very powerful continued but not uniform note resulted at the rate of seven or eight strokes per second. — Annates de Chimie, 1831. 32 Dr. Charles J. B. Williams on the Production sion constitute a large class of common noises, including grating, filing, planing, creaking of hinges, and all sounds of friction. The whistling caused by drawing the finger-nail quickly over a silk fabric is of the same kind, and owes its more musical character to the regularity of the threads. The highest audible sounds may be excited in this way. Dr. Wol- laston noticed that the shrill notes of the bat and of some Grylli are inaudible to many ears. It is well remarked by Sir John Herschel, that one reason of this may be their very low force; and that if by mechanism we could strike on an anvil a hundred thousand blows in a second, there would be heard a most deafening shriek of still higher pitch. M. Savart pro- duced an audible sound, by a wheel which gave in a second 24,000 strokes, which he counts as 48,000 vibrations, which are much higher than the limits of audibility assigned by Dr. WoUaston*. I believe that a higher sound is also elicited in the action of the wheel for the combustion of steel exhibited at the Gallery of Practical Science in Adelaide Street. This wheel is 11 inches in diameter, and revolves 8500 times in a minute, and when the steel touches it, some sounds are heard far too high to be named on any musical scale, yet super- abundantly audible to all ears. Solid conductors would pro- bably convey sounds too acute to be transmitted through the air (8.). III. On some Modifications of Echoes, 14. The prolonged note produced by a succession of echoes from a series of palisades, and between two parallel walls, has been noticed by Dr. Young, Sir John Herschel, and others; but there are some points with respect to the latter instance that merit further consideration. Between two parallel surfaces, as two stone walls, or the ceiling and paved floor of a low room, the echo will take the character of a tone, prolonged iu proportion to the reflecting power of the surfaces, and high in pitch in proportion to their nearness. The latter may be calculated roughly by dividing the velocity of sound through air by the distance of the reflecting surfaces. Each reflection constitutes a sound ; and if these sounds reflected to the ear exceed in rate the vibrations of the original sound, the pitch of the echo will be raised in proportion (10.). But the pulses which fall obliquely, having a longer course, would necessarily be fewer, and reach the ear somewhat later; hence these echoes terminate in a lower key. This law of the modifica- tion of sound by repeated reflection explains a great many ♦ Annalcs de Chimie, 1830. [Dr. Wollaston's paper on this subject will be found in the Phil. Mag., vol. Ivii. p. 187 — Edit.] and Propagation of Sound. 33 familiar phffinomena; of these, two deserve notice as requiriijtr further explanation. 15. The echoes of a large empty room are often of a lower pitch than the original sound; a whistle, for instance, although answered by a similar note, will also excite a number of echoes that are obviously lower. As this depth of echo is in proportion to the size of the room (14.), there is reason to be- lieve that it arises from the various stray pidses falling into vibrations corresponding with their successive periods of re- flection. Every room has its proper pitch of echo; and this depends on the relation of the prevailing diameter of the room to the velocity of sound through air. Thus, in a room 20 feet square, or, better, a circular one 20 feet in diameter, the prin- cipal echo of the room, besides the simple one, would consist of about 56 vibrations in a second. 16. Little reflecting cavities of a few inches' diameter must necessarily be still higher in their echoes (14.), and it is these echoes that give the tinkling sound to many hollow bodies when struck. The remarkable reverberation of empty barrels is a coarse instance; no sound of lower pitch will be reechoed within them. If the mouth of a glass or earthenware bottle be applied to the ear, and then tapped on the outside, each stroke will appear tinkling ; and that this proceeds from the internal echo, and not from the material, is plain from the fact, that muffling the vessel in any v/ay by the hand, or by a cloth, does not stop the tinkle of the interior, although heard externally the stroke is a mere dead tap. The peculiar ring- ing sound which accompanies blowing or whistling into a bottle is referrible to the same cause, and is quite distinct from the longitudinal vibration of the whole column of air excited by blowing laterally as with a Pan-pipe. Spherical cavities give the longest and most uniform echo, for the obvious rea- son that the reflections are nearly of the same length (14.).* 17. Very distant notes, such as street cries or the sound * I was led to these facts in seekinp; the cause of a similar phaenomenon which occurs in the human body, and is an important sign of disease. In pneumatoothorax, where a cavity is formed by air getting between the lungs and the walls of the chest, coughing or speaking is often attended by a tinkling echo, called by M.Laennec tintement metallique. I formerly rank- ed as of this kind the tinkling sound which occurs in the ear itself when- ever it is closed, and the hand, or whatever is used to close it, is tapped : each stroke sounds like the clink of a piece of metal. But a? I find that diminishing the cavity by introducing a small solid object far inio the ear does not raise the tone, whereas forcing air through the Eustachian tube so as to press on the tympanum destroys the sound, I am inclined to think that the clink in question is produced by the vibration of the tym- panum itself: accordingly I have found that in several who are slightly deaf in one ear, this note of the tympanum is higher in the ear that hears best. Third Series, Vol. 6. No. 31. Jan. 1835. F 34? Dr. Faraday's Experimental Researches in Electricity, of a horn, are often heard only in their upper octave. This singular foot I presume to depend on the greater strength of the moderately rapid vibrations, by which they are enabled to traverse a longer space than the fundamental note. The same thing occurs with distant echoes ; and, although natural philosophers have not noticed this circumstance, melodrama- tists have successfully availed themselves of it to represent the effect of an echo on the stage. So also Shakspeare : ** Babbling echo mocks the hounds, Replying shrilly to the well tuned horns." Again, " Thy hounds shall make the welkin answer them, And fetch shrill echoes from their hollow earth.' Half-moon Street, Nov. 13, 1834. V. Experimental Researches in Electricity. — Eighth Series, By Michael Faraday, D.C.L.F,R.S.FullerianProf, Chem-. Royal Institution,^ Corr. Memb. Royal and Imp» Acadd. of Sciences, Paris, Petershurgh, Florence, Copenhagen, Berlin, ^. 14«. On the Electricity of the Voltaic Pile; its source, quantity, intensity, and general characters, f i. Oil simple Voltaic Circles. 51 ii» On the intensity neces- sary for Electrolyzation. % m. On associated Voltaic Circles, or the Voltaic Battery, f iv. On the resist^ ance of an Electrolyte to Electrolytic action. % v. Ge^ neral remarks on the active Voltaic Battery. f i. On simple Voltaic Circles. 875. T^HE great question of the source of electricity in the -■- voltaic pile has engaged the attention of so many eminent philosophers, that a man of liberal mind and able to appreciate their powers would probably conclude, although he might not have studied the question, that the truth was some- where revealed. But if in pursuance of this impression he were induced to enter upon the work of collating results and conclusions, he would find such contradictory evidence, such equilibrium of opinion, such variation and combination of theory, as would leave him in complete doubt respecting what he should accept as the true interpretation of nature: he would be forced to take upon himself the labour of repeating * From the Philosophical Transactions for 1834. Part II. p. 425. This paper was received by the Royal Society April 7th, and read June 5th, 1834. .lend. kZdin. Iha.Ma^. ScJaum.I'L I. Vol. S. F^.l. Dip. Z ^^.27. ^ y -o^ L T \^ * ^ L A ^ ■^ ' I Z PZ PZ P p J'i^.J£>. I'iff.20. Ti^.21. -o- ^g7.22. ^^.:^. Tiff. 3 o. F^.ai. ,^(!SaM,te.A*o. '^>v. f L Hl^^j. On the Source of Electricity in the Voltaic Pile, 35 and examining the facts, and then use his own judgement on them in preference to that of others. 876. This state of the subject must, to those who have made up their minds on the matter, be my apology for entering upon its investigation. The views I have taken of the definite ac- tion of electricity in decomposing bodies (783*.)) and the iden- tity of the power so used with the power to be overcome (855.), founded not on a mere opinion or general notion, but on facts which, being altogether new, were to my mind precise and conclusive, gave me, as I conceived, the power of examining the question with advantages not before possessed by any, and which might compensate, on my part, for the superior clear- ness and extent of intellect on theirs. Such are the consider- ations which have induced me to suppose I might help in deciding the question, and be able to render assistance in that great service of removing doubtful kno'mledge. Such know- ledge is the early morning light of every advancing science, and is essential to its development ; but the man who is en- gaged in dispelling that which is deceptive in it, and revealing more clearly that which is true, is as useful in his place, and as necessary to the general progress of the science, as he who first broke into the intellectual darkness, and opened a path into knowledge before unknown to man. 877. The identity of the force constituting the voltaic cur- rent or electrolytic agent, with that which holds the elements of electrolytes together (855.), or in other words with chemi- cal affinity, seemed to indicate that the electricity of the pile itself was merely a mode of exertion, or exhibiuon, or exist- ence o^ true chemical action^ or rather of its cause; and I have consequently already said that 1 agree with those who believe that the supply of electricity is due to chemical powers (857.). 878. But the great question of whether it is originally due to metallic contact or to chemical action, i, e, whether it is the first or the second which originates and determines the cur- rent, was to me still doubtful ; and the beautiful and simple experiment with amalgamated zinc and platina, which I have described minutely as to its results (863, &c.), did not decide the point ; for in that experiment the chemical action does not take place without the contact of the metals, and the metallic contact is inefficient without the chemical action. Hence either might be looked upon as the determining cause of the current. 879. I thought it essential to decide this question by the [* All the numbers referred to in Mr. Faraday's Eighth Series, now given, from 661 to 874 both inclusive, will be found in the Seventh Series, given in. our last volume.— Edit.] F2 36 Dr. Faraday's Experimental Researches in Electricity, simplest possible forms of apparatus and experiment, that no fallacy might be inadvertently admitted. The well known difficulty of effecting decomposition by a single pair of plates, except in the fluid exciting them into action (863.)? seemed to throw insurmountable obstruction in the way of such experi- ments ; but I remembered the easy decomposibility of the so- lution of iodide of potassium (316.), and seeing no theoretical reason, if metallic contact was not essential, why true electro- decomposition should not be obtained without it, even in a single circuit, I persevered and succeeded. 880. A plate of zinc, about eight inches long and half an inch wide, was cleaned and bent in the middle to a right an- gle, fig. 1. a. Plate I. A plate of platina, about three inches long and half an inch wide, was fastened to a platina wire, and the latter bent as in the figure b. These two pieces of metal were arranged together as delineated, but as yet with- out the vessel c, and its contents, which consisted of dilute sulphuric acid mingled with a little nitric acid. At x a piece of folded bibulous paper, moistened in a solution of iodide of potassium, was placed on the zinc, and was pressed upon by the end of the platina wire. When under these circumstances the plates were dipped into the acid of the vessel c, there was an immediate effect at x, the iodide being decomposed, and io- dine appearing at the anode {66o.\ i.e. against the end of the platina wire. 881. As long as the lower ends of the plates remained in the acid the electric current continued, and the decomposition proceeded at x. On removing the end of the wire from place to place on the paper, the effect was evidently very powerful ; and on placing a piece of turmeric paper between the white paper and zinc, both papers being moistened with the solution of iodide of potassium, alkali was evolved at the cathode (663.) against the zinc, in proportion to the evolution of iodine at the anode. Hence the decomposition was perfectly polar, and decidedly dependent upon a current of electricity passing from the zinc through the acid to the platina in the vessel c, and back from the platina through the solution to the zinc at the paper x. 882. That the decompostion at x was a true electrolytic ac- tion, due to a current determined by the state of things in the vessel c, and not dependent upon any mere direct chemical action of the zinc and platina on the iodide, or even upon any current which the solution of iodide might by its action on those metals tend to form at x, was shown, in the first place, by removing the vessel c and its acid from the plates, when all decomposition at x ceased, and in the next by connecting Metallic Contact not necessary to the Voltaic Current, 37 the metals, either in or out of the acid, together, when decom- position of the iodide at jr occurred, but in a reve7'se cnder; for now alkali appeared against the end of the platina wire, and the iodine passed to the zinc, the current being the con- trary of what it was in the former instance, and produced di- rectly by the difference of action of the solution in the paper on the two metals. The iodine of course combined with the zinc. 883. When this experiment was made with pieces of zinc amalgamated over the whole surface (863.), the results were obtained with equal facility and in the same direction, even when only dilute sulphuric acid was contained in the vessel c (fig. 1.). Whichever end of the zinc was immersed in the acid, still the effects were the same : so that if, for a moment, the mercury might be supposed to supply the metallic contact, the reversion of the amalgamated piece destroys that objection. The use of unamalgamated zinc (880.) removes all possibility of doubt. 884. When, in pursuance of other views (930.), the vessel c was made to contain a solution of caustic potash in place of acid, still the same results occurred. Decomposition of the iodide was effected freely, though there was no metallic con- tact of dissimilar metals, and the current of electricity was in the same direction as when acid was used. 885. Even a solution of brine in the glass c could produce all these effects. 886. Having made a galvanometer with platina wires and introduced it into the course of the current between the platina plate and the place of decomposition t, it was affected, giving indication of currents in the same direction as those shown to exist by the chemical action. 887. If we consider these results generally, they lead to very important conclusions. In the first place they prove, in the most decisive manner, that metallic contact is not necessary for the production of the voltaic current. In the next place they show a most extraordinary mutual relation of the che- mical affinities of the fluid which excites the current, and the fluid which is decomposed by it. 888. For the pupose of simplifying the consideration, let us take the experiment with amalgamated zinc. The metal so prepared exhibits no effect until the current can pass : it at the same time introduces no new action, but merely removes an influence which is extraneous to those belonging either to the production or the effect of the electric current under in- vestigation (1000.); an influence also which, when present, tends only to confuse the results. 889. Let two plates, one of amalgamated zinc and the other of platina, be placed parallel to each other (fig. 2.), and intro- 38 Dr. Faraday's Experimental Researches in Electricity, duce a drop of dilute sulphuric* acid, j/, between them at one end : there will be no sensible chemical action at that spot unless the two plates are connected somewhere else, as at P Z, by a body capable of conducting electricity. If that body be a metal or certain forms of carbon, then the current passes, and, as it circulates through the fluid at ?/, decomposition ensues. 890. Then remove the acid from y, and introduce a drop of the solution of iodide of potassium at x (fig. 3.). Exactly the same set of effects occur, except that when the metallic communication is made at P Z, the electric current is in the opposite direction to what it was before, as is indicated by the arrows, which show the courses of the currents (667.). 891. Now both the solutions used are conductors, but the conduction in them is essentially connected with decomposi- tion (8.58.) in a certain constant order, and therefore the ap- pearance of the elements in certain places shows in what di- rection a current has passed when the solutions are thus em- ployed. Moreover, we find that when they are used at op- posite ends of the plates, as in the last two experiments (889. 890.), metallic contact being allowed at the other extremities, the currents are in opposite directions. We have evidently, therefore, the power of opposing the actions of the two fluids simultaneously to each other at the opposite ends of the plates, using each one as a conductor for the discharge of the current of electricity, which the other tends to generate; in fact, sub- stituting them for metallic contact, and combining both ex- periments into one (fig. 4.). Under these circumstances there is an opposition of forces ; the fluid, which brings into play the stronger set of chemical affinities for the zinc (being the dilute acid,) overcomes the force of the other, and determines the formation and direction of the electric current ; not merely making that current pass through the weaker liquid, but ac- tually reversing the tendency which the elements of the latter have in relation to the zinc and platina if not thus counter- acted, and forcing them in the contrary direction to that they are inclined to follow, that its own current may have free course. If the dominant action at y be removed by making metallic contact there, then the liquid at x resumes its power; or if the metals be not brought into contact at y, but the affi- nities of the solution there weakened, whilst those active at x are strengthened, then the latter gains the ascendancy, and the decompositions are produced in a contrary order. 892. Before drawing ^^final conclusion from this mutual dependence and state of the chemical affinities of two distant portions of acting fluids (916.), I will proceed to examine more minutely the various circumstances under which the re- action of the decomposed body is rendered evident upon the Use of Metallic Contact in the Voltaic Apparatus, 39 action of that body, also in the act of decomposition, which produces the voltaic current. 893. ThQ use oi metallic contact in a single pair of plates, and the cause of its great superiority above contact made by other kinds of matter, become now very evident. When an amalgamated zinc plate is dipped into dilute sulphuric acid, the force of chemical affinity exerted between the metal and the fluid is not sufficiently powerful to cause sensible action at the surfaces of contact, and occasion the decomposition of water by the oxidation of the metal, although it is sufficient to produce such a condition of the electricity (or the power upon which chemical affinity depends) as would produce a current if there were a path open for it (916. 956.); and that current would complete the conditions necessary, under the circumstances, for the decomposition of the water, 894. Now the presence of a piece of platina touching both the zinc and the fluid to be decomposed, opens the path re- quired for the electricity. Its direct communication with the zinc is effectual, far beyond any communication made between it and that metal, {i. e. between the platina and zinc,) bv means of decomposable conducting bodies, or, in other words, electrolytes, as in the experiment already described (891.); because, when they are used, the chemical affinities between them and the zinc produce a contrary and opposing action to that which is influential in the dilute sulphuric acid ; or if that action be but small, still the affinity of their component parts for each other has to be overcome, for they cannot conduct without suffering decomposition : and this decomposition is found experimentally to react back upon the forces which in the acid tend to produce the current (904. 910. &c.), and in numerous cases entirely to neutralize them. Where direct contact of the zinc and platina occurs, these obstructing forces are not brought into action, and therefore the production and the circulation of the electric current and the concomitant ac- tion of decomposition are then highly favoured. 895. It is evident, however, that one of these opposing ac- tions may be dismissed, and yet an electrolyte be used for the purpose of completing the circuit between the zinc and platina immersed separately into the dilute acid; for if, in fig. 1, the platina wire be retained in metallic contact with the zinc plate «, at X, and a division of the platina be made elsewhere, as at 5, then the solution of iodide placed there, being in contact with platina at both surfaces, exerts no chemical affinities for that metal ; or if it does, they are equal on both sides. Its power, therefore, of forming a current in opposition to that dependent upon the action of the acid in the vessel r, is re- moved, and only its resistance to decomposition remains as 40 Dr. Faraday's' Experimental Researches in Electricity, the obstacle to be overcome by the affinities exerted in the di- lute sulphuric acid. 896. This becomes the condition of a single pair of plates where metallic contact is allowed. In such cases, only one set of opposing affinities are to be overcome by those which are dominant in the vessel c ; whereas, when metallic contact is not allowed, two sets of opposing affinities must be con- quered (894..). 897. It has been considered a difficult, and by some an im- possible, thing to decompose bodies by the current from a single pair of plates, even when it was so powerful as to heat bars of metal red hot, as in the case of Hare's calorimeter, arranged as a single voltaic circuit, or of Wollaston's power- ful single pair of metals. This difficulty has arisen altogether from the antagonism of the chemical affinity engaged in pro- ducing the current with the chemical affinity to be overcome, and depends entirely upon their relative intensity; for when the sum of forces in one has a certain degree of superiority over the sum of forces in the other, the former gains the ascendancy, determines the current, and overcomes the latter forces so as to make the substance exerting them yield up its elements in perfect accordance, both as to direction and quan- tity, with the course of those which are exerting the most in- tense action. 898. Water has generally been the substance, the decom- position of which has been sought for as a chemical test of the passage of an electric current. But I now began to perceive a reason for its failure, and for a fact which I had observed long before (315. S16*.) with regard to the iodide of potassium, namely, that bodies would differ in facility of decomposition by a given electric current, according to the condition and in- tensity of their ordinary chemical affinities. This reason ap- peared in their reaction back upon the affinities tending to cause the current; and it appeared probable, that many sub- stances might be found which could be decomposed by the current of a single pair of zinc and platina plates immersed in dilute sulphuric acid, although water resisted its action. I soon found this to be the case, and as the experiments offer new and beautiful proofs of the direct relation and opposition of the chemical affinities concerned in producing and in resist- ing the stream of electricity, I shall briefly describe them. 899. The arrangement of the apparatus was as in fig. 5. The vessel v contained dilute sulphuric acid ; Z and P are the zinc and platina plates ; a, Z>, and c are platina wires ; the de- [* These numbers refer to part of the author's Third Series of Re- searches in Electricity, which will be found in Lonu. and Edinb. Phil. Mag. vol. iii. p. 254. — Edit.] Decompositions hy a Single Pair of Plates, 41 compositions were effected at a:, and occasionally, indeed ge- nerally, a galvanometer was introduced into the circuit at^: its place only is here given, the circle at g having no refer- ence to the size of the instrument. Various arrangements were made at ^, according to the kind of decomposition to be effected. If a drop of liquid was to be acted upon, the two ends were merely dipped into it; if a solution contained in the pores of paper was to be decomposed, one of the extremities was connected with a platina plate supporting the paper, whilst the other extremity rested on the paper, e, fig. 12 : or some- times, as with sulphate of soda, a plate of platina sustained two portions of paper, one of the ends of a and c resting upon each piece, immediate contact with the apex of the conoid ; whereas, in the comet of 1811, the apex of the conoid was separated from the nucleus by a dark interval of considerable extent. What Hevel represents as a horn proceed- ing from the nucleus, was merely the northern border of the conoid, which, according to Hooke, is very much brighter than the southern. It is to be expected that on its approach- ing return astronomers will bestow all possible attention on the remarkable peculiarities of form which it will probably only exhibit after the perihelion, and on the changes of appear- ances it undergoes. In the drawing made by Tobias Mayer, on the margin of his Journal, 30th of April 1759, (" Astro- nomical Observations made at Gottingen, from 1756 to 1761, &c., London 1826, fol. p. 43.") no indication is given of this bright conoid, which, 48 days after the comet's nearest ap- proach to the sun, had entirely disappeared. Although the comet, on this occasion, will not exhibit any extraordinary splendour, yet the circumstances of its return will be favourable to science, as it will be possible to see and observe it during a considerable length of time. In the southern hemisphere of our earth, where, thanks to Great Britain, several observatories have been erected, and compe- tent astronomers established, the comet will be seen on ex- tricating itself from the sun's rays, after the perihelion pass- age, from about the end of December 1835, till the spring of 1836. In the North of Europe, indeed, on account of its con- tinual low altitude above the horizon, it will come less into view; and when in the months of March and April 1836, it has attained to a greater height in the constellations of the Crow and the Cup, it will be at so great a distance from the sun and the earth, that it will appear only as a feeble nebula in the most powerful telescopes. While engaged in writing out the last part of this short memoir, I was equally honoured and gratified by receiving an entirely unexpected visit from Professor Rosenberger. Professor Rosenberger is also fully convinced that it is not H2 52 Mr. Phillips on the Hydrates ofBarytes and Sironiia. possible, on nccountof the still undetermined resistance of the a'tiier, to predict with any certainty the precise day of the pe- rihelion passage in 1835, without computing the amount of the perturbations from 1607 to 1682. As there is no longer time for this, he has resolved to suspend for the present his calcu- lation of the perturbations from 1759 to 1835, which he has already carried so far as 270° of eccentric anomaly, and to wait the result of experience. He will then resume his cal- culations, and carry them back to 1607, in order that the effect of the resistance of the aether on this comet may be determined with all possible accuracy. Olbers. VII. On the Quantity of Water contained in crystallized Barytes and Strontia. By Richard Phillips, F.R.S. L.Sf E. S^c, Lecturer on Chemistry at St. Thomas's Hospital. "PJR. D ALTON in his Chemical Philosophy (vol. i. p. 523.) -■-^ states that he found that 80 grains of fresh crystallized ba- rytes, dissolved in water and saturated with sulphuric acid, gave 36 grains of dried sulphate of barytes; and hence he inters, that in the crystals 20 atoms of water are united to one atom of barytes. On looking into chemical works I do not find that any other chemist has attempted to ascertain the quantity of water which these crystals contain ; indeed Dr. Dalton's state- ment is quoted by both Thomson and Turner. Not remembering any case in which a binary compound like barytes unites with so many as 20 equivalents of water, and as Dr. Dalton admits that his experience on the crystals of ba- rytes has been limited, I was induced to repeat the experiment, in order to ascertain whether or not these crystals formed an exception to what appears to me to be a general rule. With this intention I decomposed some sulphate of barytes by heating it with charcoal, and dissolving the sulphuret of barium in water: the solution was heated with peroxide of copper, and filtered while hot. On cooling, crystals of barytes were plentifully obtained, which were dried, as well as they could be, by repeated pressure between folds of blotting-paper. One hundred parts of these crystals were supersaturated with muriatic acid, and the solution was decomposed by sulphuric acid: in one experiment 72*19 parts and in another 72*15 parts of sulphate of barytes were obtained, giving a mean of 72*17; now as 116 of sulphate ot" barytes contain 76 of the earth, 72*17 parts contain 1^7*28 of barytes, which, deducted from 100, the crystals employed, leave 52*72 as the quantity of water which they contained. Now a compound of Reviews^ and Notices respecting New Books, 53 1 equivalent barytes 76 1 -^ S'^^^\m loo 10 equivalents water 90/ ^^^'^ \ 54*2/ ^""* 166 which agrees sufficiently well with my experiment to show that the crystals contain only 10 equivalents of water, instead of 20 as stated by Dr. Dal ton. According to Dr. Hope, the crystals of strontia contain 68 per cent, of water, and Dr. Dalton concludes from this state- ment that they contain 12 equivalents of it. I prepared some crystals of strontia in the same manner as those of barytes above described; they were dried in a similar mode, and taking the mean of two experiments, which differed but very little, 100 parts of the crystals, after saturation with muriatic acid and treatment with carbonate of ammonia, gave 51*57 of car- bonate of strontia; and as 74 of this substance consist of 22 of carbonic acid and 52 base, 51*57 contain 36*24 of strontia, which, deducted from 100, the crystals experimented upon, leave 63*76 as the quantity of water contained in them. The crystals are therefore evidently composed of 1 equivalent of strontia 52, or 36*621 . . 10 equivalents of water 90, or 63*38 J "^ 142 and resemble those of barytes with respect to the quantity of water which they contain. VIII. Reviews, and Notices 7'especting New Books. A Manual of Mineralogy^ comprehending the more recent Discoveries in the Mineral Kingdom. By Robert Allan, Esq., F.R.S.E., M.G.S.L.y 8fc. 1 vol. 8vo, London, 1834. MINERALOGY, in its most limited sense, is that branch of Na- tural History which takes cognizance of the forms and exter- nal properties of mineral substances, with a view to their accurate discrimination and to their arrangement into groups or classes. Thus considered, it may perliaps be thought scarcely to aspire to the dignity of a science; but, by its connexions with other branches of human knowledge, it acquires a claim to higher distinction. All the materials of which our globe is composed, however complex in appearance, are resolvable into more simple minerals. In the older rocks, especially, we recognise, by the descriptions of the minera- logist, the proximate materials which compose and characterize those rocks; and hence Mineralogy has been regarded as the alphabet of Geology. The identification of the mass also often depends es- sentially on that of its component minerals. 54 Review of AllarCs Manual of Mineralogy. Of late years Mineralogy has extended its alliances to other sci- ences. From examples taken from the mineral kingdom, Mitscher- lich derived his first views of isomorphism ; and by the optical pro- perties of minerals formed in the laboratory of nature, Brewster and Herschel were led to the discovery of laws, that not only explain ob- scure phaenomena, but furnish, in their turn, new instruments for investigating the structure and differences of mineral substances*. With Chemistry, also, the relations of mineralogy are constantly be- coming closer and more numerous, each science rendering to the other the tribute of new facts and new principles. It is time, however, to speak of the work before us. It is an un- pretending volume, manifesting great diligence in the collection of its materials, and equal judgement in their arrangement. How much such a book was wanted, every British mineralogist must have sensibly felt. Since the publication of Mr. William Phillips's *' Elementary Introduction to Mineralogy,"(an excellent work for the time, and still valuable on many accounts,) eleven years have elapsed j and nine years have passed since that of Haidinger's Translation of Mohs's work. During that long interval, a vast number of new minerals have been discovered, the accounts of which can only be consulted by laborious search though the periodical records of science. To incorporate these with our previous knowledge was not, as it might be supposed, a work of mere labour. It was quite necessary that the compiler should himself be thoroughly versed in practical mine- ralogy, and qualified to correct and improve the descriptions of pre- vious writers. In the preface, the author informs us that his descrip- tions have in most instances been carefully collated with specimens in the collection of his late father (well known to be almost un- rivalled for its excellence) j and the figures in outline of crystallized minerals have been carefully drawn by himself from the best ex- amples in that cabinet f. The localities and modes of occurrence of minerals, which are numerous and correct, have been assigned from his own observations in the principal mining districts of this country and the Continent. In many instances he has noticed in what pub- lic and private cabinets the best specimens of the rare and most costly minerals may be consulted. An " Introduction," prefixed to the volume, conveys elementary information in a manner well adapted to beginners in the science j and a copious index gives the reader access to the almost endless synonyms which have so greatly perplexed mineralogical language. We have no hesitation, then, in pronouncing Mr. Allan's work to be a safe guide for the student, and a valuable book of reference to the experienced mineralogist. *^* * See Prof. Whewell's Report on Mineralogy, read at the Meeting of the British Association in 1832; and Sir John llerschel's Preliminary Dis- course, part III. chap. iv. t The collection has been publicly announced for sale by auction at Edinburgh about the middle of January. It is earnestly to be hoped that it may become the property of some public Institution, where, by being made accessible to men of science with the same liberality as by its late possessor, its utility may be extended and perpetuated. [ 55 ] IX. Proceedings of Learned Societies. ROYAL SOCIETY. [Continued from vol. v. p. 4.^9.] 1834. nPHE following Papers were read : June 19. — -■- 1 . ** Observations on the Teredo navalis and Limnoria terebrans, as at present existing in certain localities of the British Islands." By William Thompson, Esq., Vice-President of the Natural History Society of Belfast. Communicated by J. G. Children, Esq. Sec. U.S. The opinion which has been advanced, that the Teredo navalis is no longer to be found on the British coast, is shown by the author to be erroneous ; for numerous specimens of that destructive animal, collected from the piles used in the formation of the pier at Port- patrick in Ayrshire, were furnished to him by Captain Frayer, R.N. (of His Majesty's Steam-packet Spitfire). Some of these specimens had attained the length of nearly two feet and a half, a magnitude at least equal to, if not exceeding, the largest brought from the Indian seas. After giving a description of the animal, the author enters into an inquiry into the agency it employs to perforate the timber which it consumes as food, and in which it establishes its habitation. He ascribes to the action of a solvent, applied by the proboscis, the smooth and rounded termination of its cell, which is afterwards enlarged by the mechanical action of the primary valves. The author then gives an account of the natural history and opera- tions of another animal, the Limnoria terebrans, of Leach, belong- ing to the class of Crustacea, whose depredations on timber are no less extensive and formidable than the Teredo* At Portpatrick it ap- pears that both these animals have combined their forces in the work of destruction, the Teredo consuming the interior, and the Limnoria the superficial parts of the wood; the latter continuing its labours until it comes in contact with the shells of the former, so that the whole mass is speedily deprived of cohesion. It is stated, on the au- thorities of Mr. Hyndman and Mr. Stephen, that the Limnoria is al- ready committing great ravages in the timber at Donaghadee. 2. " On the Nervous System of the Sphinx ligustri (Linn.) during the latter Stages of its Pupa and its Imago States ; and on the Means by which its Development is effected." By George Newport, Esq. Communicated by P. M. Roget, M.D., Sec.'R.S. In a paper formerly read to the Royal Society, and printed in the Philosophical Transactions*, the author has given a description of the anatomy of the nervous system of the Sphinx ligustri in its larva, and the earlier periods of its pupa, state ; and he has since prosecuted the inquiry then commenced, following the changes of structure through the remaining stages, until the insect has arrived at its full develop- ment. He enters into minute details of all these changes, which vary considerably in the rapidity with which they take place at dif- ferent periods, according as the vital powers are called into action by * An abstract of Mr. Newport*s former paper will be found in Lond.and Edinb. Phil. Mag., vol. i. p. 382. 56 Royal Society, external circumstances, or become exhausted by their efforts at effect- ing the growth or modifying the form of different parts. Thus the ganglia and nervous cords undergo great changes both in their form and situation, and also in their number, during the passage of the insect from the larva to the pupa state 3 and after these changes have been carried to a certain extent, they are suspended for several weeks, during which the insect remains in a state of hybernation ; but at the expiration of this period the changes again proceed, and are continued uninterruptedly, till the insect attains its ultimate or perfect stage of development. The Sphinx ligustri remains in the pupa state during at least forty-two or forty-three weeks ; thus affording ample oppor- tunities of examining the whole progress of the changes which take place in the structure of different parts. The concentration of the nervous system, which was commenced in the larva, proceeds to a mucn greater extent while the insect is inclosed in the pupa, and is continued for a short time after it has assumed the imago state. The double origin and connexions of the nerves distributed to the wings are described, and a conjecture offered as to the object of this ar- rangement, which appears designed to establish a harmony of action between the wings, in those insects, especially, which are remarkable for velocity and power of flight j a different disposition being adopted in those which fly with less regularity or speed. The nerves of the organs of sense, as the antennae, eyes, proboscis, and apparatus for manducation, are traced and minutely described, and a comparison instituted between them and the nerves which have similar offices in vertebrated animals. The author traces the origin and course of the nerve corresponding to the pneumo-gastric, or par vagum, and shows that it is distributed chiefly to the organs of digestion and the respi- ratory passages. He next describes the anterior lateral cephalic ganglia, which, from their position, might be regarded as auxiliary brains. The situation and course of .another nervous tract, which from its extensive connexions and peculiar mode of distribution is considered as corresponding to the sympathetic system, are also traced. The author notices a set of nerves which, adopting the views of Sir Charles Bell, he considers as analogous to those which the lat- ter has denominated the respiratory nerves of vertebrated animals ; and among a great number of interesting observations, of which it is impossible to give any abridged account, one of the most remarkable is the discovery that the priniary longitudinal nervous cords of in- sects consist of two tracts, the one situated over the other, corre- sponding to the two columns of which the spinal cord consists in ver- tebrated animals j the one appropriated to sensation, and the other to voluntary motion ; the nerves from each of these tracts being variously combined, according to the purposes they are designed to fulfill. This important distinction, which was first traced in the nervous cords of the Lobster, was afterwards distinctly observed by the author in the Scorpion and the Scolopendra, and lastly, in several species of insects, as the Grijllus viridissimus, the Carabus, the Papilio urticeB, and the Sphinx ligustri. Numerous drawings of the parts described accom- pany the paper. Royal Society, 51 3. " Observations on the Torpedo, with an account of some addi- tional experiments on its Electricity." By John Davy, M.D., F.R.S., Assistant Inspector of Army Hospitals. The first part of this paper is occupied by an investigation of the circumstances attending the foetal development of the Torpedo. In the first stage of embiyonic growth u^hich the author had an oppor- tunity of observing, when the embryo was Jibout seven tenths of an inch in length, it had neither fins nor electrical organs, nor any ap- pearance of eyes -, it exhibited short external branchial filaments, not yet carrying red blood 3 and theie vi^as a red spot in the situation of the heart, communicating by red vessels in the umbilical cord with the vascular part of the egg. There is no membrane investing the foetus, as is the case with some species o( Soualif nor any fluid in the uterine cavity 3 neither could the author find any urea or lithic acid in that cavity. By taking the mean of many observations, it appeared that the weight of the egg, betore any appearance of the embryo, is 1 82 grs., and after iis appearance, including the weight of the latter, 177 grs.; while the weight of tlie mature fish is about 479 grs. ; showing an augmentation of more than double. Ttius it differs remarkably, in this respect, from the foetal chick, which at its full time weighs consider- ably less than the original yolk and white from which it is formed. No communication can be traced between the foetus of the Torpedo and the parent, through the medium of any vascular or cellular struc- ture ; and the stomach of the former is always found empty. Hence the only apparent source of nourishment is absorption from the surface ; and the author states his reasons for believing that the branchial fila- ments are the principal absorbing organs, the materials they receive being chiefly employed in the construction of the electrical organs, while those which enter into the composition of the body generally are absorbed by the general surface of the foetus. The author is led, from his researches, to the conclusion that the mode of reproduction in the Torpedo is intermediate between the viviparous and the ovo- viviparous. In the second part of the paper, the author discusses the question as to the number of species of the genus Torpedo existing in the Me- diterranean J and concludes that there are only two, viz. the Ochiu- tella and the Tremola. 4. *' Appendix to a former Paper on Human Osteology*." By Wal- ter Adam, M.D. Communicated by Dr. Prout, F.R.S. This appendix contains linear representations of various dimen- sions of the bones of the human body, both male and female, with a view to facilitate the comparison of the human frame with that of other animals, and reduce it to definite laws. The author states that many of the rectilinear dimensions of human bones appear to be mul- tiples of one unit, namely, the breadth of the cranium directly over the external passage of the ear ; a dimension which he has found to be the most invariable in the body. No division of that dimension * An abstract of Dr. Adam's former paper was given in Lend, and Edinb. Phil. Mag., vol. iii. p. 457. Third Series. Vol. 6. No. 31. Jan. 1835. I .58 RoyaL Society, was found by him to measure the other dimensions so accurately as that by seven, or its multiples. Of such seventh parts there appear to be twelve in the longitudinal extent of the back, and ninety-six in the height of the whole body. f). ** On the Repulsive Power of Heat." By the Rev. Baden Powell, M.A., F.R.S., Savilian Professor of Geometry in the University of Oxford. The expansion of bodies by heat appearing to imply a mutual re- pulsion of their particles, it becomes a question whether such repul- sive power may not be excited by it between particles or masses of matter, at sensible as well as insensible distances. After noticing the partial investigations of this question by Libri, Fresnel, Saigey, and Professor Forbes, the author describes the method he has employed with a view to its solution, and which consisted in applying heat to two lenses of glass, pressed together so as to exhibit the colours of thin plates; the variation of the tints furnishing exact indications of the most minute changes of distance between the surfaces, by what- ever causes they may be produced. The conclusion he deduces from his experiments, conducted on this plan, is that the separation of the surfaces is of a different character, and is greater than can be accounted for by the mere change of figure produced by the heat; and is therefore in part to be ascribed to a real repulsive action between the surfaces of the glasses derived from the power of heat. He also found, on trying similar experiments with glass in contact with a metallic surface, that the results were considerably influenced by the radiating power of the latter ; the effect being increased when this power was greater, and also by all other causes tending to the more rapid communication of heat. This is still more apparent when the coloured rings are formed in a thin plate of water interposed between the lenses, and where the effects are independent of radiation. 6. " Analysis of the Moira Brine Spring near Ashby-de~la-Zouch, Leicestershire, with Researches on the Extraction of Bromine." By Andrew Ure, M.D., F.R.S.* The water derived from the spring in question is raised by means of a pump from the coal mines in the neighbourhood of Ashby-de-la- Zouch, is much used as medicinal baths, and is also administered internally, principally as a remedy for bronchocele and scrofulous tumors. The result of the analysis made by the author, is that it contains per gallon, grs. Bromide of sodium and magnesium 8* Chloride of calcium 85 1 -2 magnesium 16* sodium 3700*5 Protoxide of iron, a trace Solid contents 4575*7 • See an abstract of Prof Daubeny's paper " On the occMrrence of Iodine and Bromine in certain mineral waters of South Britain," in Phil. M:ig. and .\nnals, N.S., vol. viii. pp. Gl, 62. Royal Society. 59 After removing from the water the deliquescent chlorides of lime and magnesia by the addition of carbonate of" soda, he transmits through the mother liquor, consisting of chloride and bromide of sodium, a current of chlorine gas, till it communicates the maximum golden tint, and then adds sulphuric aether, which, by agitation, car- ries with it to the surface the bromine and chlorine, constituting a reddish yellow stratum. The proportion in which these two elements exist in the evaporated solution may be ascertained with the greatest nicety by the addition of a solution of nitrate of silver ; the method of calculation for this purpose being detailed by the author. 7. *' On the Nature and Origin of the Aurora Borealis." By the Rev. George Fisher, M.A., F.R.S. The author deduces from his own observations made during a re- sidence of two winters in high northern latitudes, taken in con- junction with the concurring testimony of various navigators and tra- vellers, the general fact that the Aurora Borealis is developed chiefly at the edge of the Frozen Sea, or wherever there is a vast accumu- lation of ice 5 and he conceives that it is produced in situations where the vapours of a humid atmosphere are undergoing rapid congelation. Under these circumstances, when viewed from a distance, it is seen fringing the upper border of the dark clouds, termed the ** sea blink," which collect over these places ; and it generally forms an arch a few degrees above the horizon, shooting out vertical columns of pale yellow light. He concludes that the Aurora Borealis is an electrical phenomenon, arising from the positive electricity of the atmosphere, developed by the rapid condensation of the vapour in the act of freezing, and the induced negative electricity of the surrounding portions of the atmosphere j and that it is the immediate consequence of the restoration of the electrical equilibrium by the intervention of the frozen particles, which being imperfect conductors, become lumi- nous while transmitting this electricity. In tropical and temperate climates this phenomenon does not occur, because the electric equi- librium is restored by means of aqueous vapours, a process which often gives rise to thunder and lightning, but never to the Aurora Borealis ; the latter being peculiar to clear, cold and dry weather. 8. " Th^orie Balistique." Far M. Le Comte de Pr^daval. Com- municated by Dr. Roget, Sec. R.S. The author inquires into the influence which he conceives the fol- lowing circumstances may have on the path of a projectile on the surface of the earth ; namely, first, the direction of the line of pro- jection relatively to the meridian or cardinal points ; secondly, the latitude of the place ; and thirdly, the barometric conditions of the atmosphere. 9. *' On the Atmospheric Tides and Meteorology of Dukhun, in the East Indies." By Lieut.-Colonel W. H. Sykes, F.R.S. The author premises detailed descriptions of the various instru- ments used in the meteorological observations recorded in this paper, and of the methods employed in obtaining his results ; of which the great features are the barometrical indications of diurnal and noc- 12 ^60 lloyal Society. turnal atmospheric tides, embracing two maxima and two minima in tUe twenty-four hours. The following are the chief topics noticed in the paper, and the principal facts established by these inquiries: namely, I. The removal of the doubts entertained by Humboldt, founded on the authority of Horsburgh, of the suspension of the at- mospheric tides during the monsoon in Western India j the existence of the four atmospheric tides already mentioned, and their occurrence within the same limiting hours as in America and Europe; the greatest mean diurnal oscillations in Dukhun taking place in the coldest months, and the smallest in the damp months ; whilst at Madras, the smallest oscillations are in the hottest months, and in Europe it is supposed that the smallest oscillations are in the coldest months. 2. The regular diurnal and nocturnal occurrence of the tides, without a single case of interversion, whatever may be the thermo- metric or hygrometric indications, or the state of the weather ; storms and hurricanes only modifying, but not interrupting them. 3. The anomalous fact of the mean diurnal oscillations being greater at Poona, at an elevation of 1823 feet, than at the level of the sea, in a lower latitude, at Madras. 4. The fact of the diurnal tides, at a higher elevation than Poona, being less, whilst the nocturnal tides are greater than at Poona ; and the seasons apparently not affecting the limiting hours of the tides. 5. The maximum mean pressure of the atmosphere being greatest in December and January ; then gradually diminishing until July and August j and subsequently in- creasing to the coldest months. 6. The very trifling diurnal and annual oscillations compared with those of extra-tropical climates. 7- The annual range of the thermometer being less in Dukhun than in Europe, but the diurnal range much greater; the maximum mean temperature occurring in April and May, and gradually de- clining until December and January ; and the observed mean tempe- rature of places on the continent of India being much higher than the calculated mean temperature according to Mayer's formula. 8. The mean annual dew-point being higher at half-past nine o'clock than either at sunrise or at four in the afternoon j the dew-point being highest during the monsoons, and lowest during the cold months, and varying considerably within very short distances ; being, for ex- ample, remarkably contrasted in Bombay and Dukhun ; and the fre- quent occurrence of dew quite locally and under anomalous circum- stances. 9. The amount of rain in Dukhun being only 20 per cent, of that falling in Bombay, 90 or 100 miles to the westward. 10. The wind being principally from the west and east, and rarely from the opposite quarters. 1 1 . The great abundance of electricity under cer- tain circumstances. 12. The rare occurrence of fogs. 13. The great amount of solar radiation ; and lastly, the singular opacity of the atmosphere during hot weather, giving rise occasionally to the mirage. A variety of tables containing the records of meteorological obser- vations, with instruments, accompany the paper. 10. ** On the Ova of the Ornithorhynchus paradoxus^ By Richard Owen, Esq. Communicated by W. Clift, Esq., F.R.S. Tloynl Society. 61 The author, in this paper, has prosecuted more immediately and more minutely than in his former communication*, the inquiry into the structure of the ovary of the Ornithorhynchus, with a view to determine its exact relations with that of the normal Mammalia, and of the ovi- parous Vertebrata. He has obtained from this investigation the full confirmation of the truth of the opinion he had previously formed, that lactation might coexist with a mode of generation essentially similar to that of the Viper and Salamander 3 and this fact has been further established by the subsequent examination which he has made of the uterine foetus of the Kangaroo. The author traces the regular gradation which obtains in different orders of Mammalia in which true viviparous or placental generation takes place, towards the ovo-viviparous or oviparous modes, in which the exterior covering of the ovum never becomes vascular, and shows that the Ornithorhynchus constitutes a connecting link in this chain. Drawings illustrative of the anatomical descriptions of the parts examined hy the author accompany the paper. 11." Observations with the Horizontal and Dipping Needles, made during a Voyage from England to New South Wales." By James Dunlop, Esq. (vommunicated by Capt. Beaufort, R.N., F.R.S. This paper contains a very numerous and uninterrupted series of magnetical observations, made in the circumstances stated in the title, and extending about 180 degrees in longitude and 100 degrees in latitude. The apparatus, of which a detailed description is given, was suspended from the roof of the cabin, and no alteration was made in its suspension from the beginning to the end of the voyage. 12. " Experiments on Light." By Henry Fox Talbot, Esq., M.P., F.U.S. This paper will be found in our last Volume, p. 321. 13. " On the Mummy Cloth of Egypt j with Observations on the Manufactures of the Ancients." By James Thomson, Esq., F.R.S. Communicated by Dr. Roget, Sec. R.S. This paper will also be found in our last Volume, p. 355. 14. " An Account of some Experiments to measure the Velocity of Electricity, and the Duration of Electric Light." By Charles Wheat- stone, Esq., Professor of Experimental Philosophy in King's College, London. Communicated by Michael Faraday, Esq., F.R.S.f The continuance for a certain time of all luminous impressions on the retina prevents our accurately ])erceiving, by direct observation, the duration of the light which occasions these impressions , but by giving the luminous body a rapid motion, which produces the appear- ance of a continued train of light along the path it has described, its condition at each moment may be ascertained, and consequently its duration determined. The same law of our sensations precludes us from direct perception of the velocity with which the luminous cause is * An abstract of Mr. Owen's former communication was given in Lond. nnd Edinb. Phil. Mag., vol. i. p. 384. See also vol. ii. p. 71 ; vol. iii. pp. 62, 301 ; vol. iv. p. 54 ; and vol. v. pp. 145. 147, 235. f See Lond. and Edinb. Phil. Mag., vol. iii. pp. 81, 204; and vol. iv. pp.113, 114. 62 Royal Society. moving, as the whole of its track, for a certain distance, appears to be equally illuminated; but by combining- a rapid transverse motion of the body from which the light proceeds, with that which it had before, its path may be lengthened to any assignable extent, and both its duration and its velocity will admit of measurement. The author gives various illustrations of this principle, and of his attempts to apply it to appreciate the duration and the velocity of the electric spark. His first experiments were made by revolving rapidly the electric appa- ratus giving electric sparks ; but in every instance they appeared to be perfectly instantaneous. He next resorted to the more convenient plan of viewing the image of the spark reflected from a plane mirror, which, by means of a train of wheels, was kept in rapid rotation on a horizontal axis. The number of revolutions performed by the mirror was ascertained, by means of the sound of a siren connected with it, and still more successfully by that of an arm striking against a card, to be 800 in a second. The angular motion of the image being twice as great as that of the mirror, it was easy to compute the interval of time occupied by the light during its appearance in two successive points of its ap- parent path, when thus viewed ; and it was ascertained that the image passed over half a degree (an angle which, being equal to about an inch, seen at a distance often feet, is easily detected by the eye,) in the 1,1 52,000th part of a second. The result of these experiments, as regarded the duration of the spark, was that it did not occupy even this minute portion of time; but when the electric discharge of a battery was made to pass through a copper wire of half a mile in length, interrupted both in the middle, and also at its two extremities, so as to present three sparks, they each gave a spectrum considerably elongated, and indicating a duration of the spark of the 24,000th part of a second. The sparks at both extremities of the circuit were perfectly simultaneous, both in their period of commencement and termination ; but that which took place in the middle of the circuit, though of equal duration with the former, occurred later, by at least the millionth part of a second, indicating a velocity of transmission from the former point to the latter of nearly 288,000 miles in a second ; a velocity which exceeds that of light itself. The following letter was read from the Chair. " British Museum, June 19th, 1834. " My Dear Sir, — His Royal Highness the President requests that, when you adjourn the meeting this evening to the 20th of No- vember, you will have the goodness to express his great regret that, un- fortunately, the state of his healtli and sight has lately been such as to render it impossible for him to preside at the ordinary meetings of the Society so frequently as it was his anxious wish to have done. His Royal Highness begs you will assure the Society that his absence has been occasioned by the cause alluded to alone, and from no feel- ing of diminished interest in the prosperity of the Royal Society, or of regard and respect for the Fellows; on the contrary. His Royal High- ness hopes that, by the blessing of Providence, his liculth will soon be in all respect"? so far re-established as to enable him, on the reassembling Geological Society, 63 of the Society, to resume the chair, and fill it with that uninterrupted regularity which it is His Royal Highness's mobt anxious wish to ob- serve, in whatever duty he undertakes. ** Ever, my dear Sir, faithfully yours, ** John George Children. " P.S. — His Royal Highness requests you will in his name bid the Fellows heartily farewell till he meets them again in November." " Francis Baily, Esq., V.P. R.S," The Society then adjourned over the long vacation, to meet again on the 20th of November. GEOLOGICAL SOCIETY. November 19th. — A paper was first read, entitled *' An Account of the raised Beach, near Hope's Nose, in Devonshire, and other recent Disturbances in that Neighbourhood," by Alfred Cloyne Austen, Esq., F.G.S. The ancient beach near Hope's Nose, noticed by Mr. Greenough in his geological map, is situated a little within the point of land so called, and rests upon a mass of transition limestone containing thin beds of shells. The distance between the ordinary line of high wa- ter and the lowest part of the deposit, is about 31 feet: its extent east and west is not more than 50 feet; and its thickness is 17 feet. How far it extends inland cannot be easily determined, as it is co- vered, in that direction, by an accumulation of detritus fallen from the neighbouring hill. The deposit varies much in texture and composition. The lowest portion is a coarse conglomerate, containing blocks of considerable size ; above this the grain becomes finer and the organic remains, consisting of shells of recent species, occur in greatest abundance. A little higher the particles are still finer, forming an exceedingly hard and compact stone, in which frequently the casts only of the shells are found. Jn the upper portion the beds are less compact, and at the highest they consist of uncemented sand, like that of a recent beach. The greater part of the deposit is formed from grau- wacke rocks, but fragments of trap also occur, and in the lowest part chalk flints. On the weathered surface, the harder beds pro- ject in thin shelves, but of sufficient strength to support a man. A deposit which encircles the Thatcher rock, about three quarters of a mileS.S.W. of Hope's Nose, presents the same characters. These are the only instances which the author could discover of a raised beach on this part of the coast. The preservation of the deposits, he considers, is owing to their resting on masses of limestone, and that the abrupt terminations which the beach at Hope's Nose presents towards the east and west, are proofs that it was once more extensive. Watcombe Fault. — The author premises his observations on the Watcombe fault by stating, that any section of the new red sand- stone of South Devon will present innumerable lines of disturbance, and that attention to these will show they have been the origin of the hills and valleys of the district j though all superficial evidence of their existence has been destroyed by their being rounded ofl'. 64? Geological Society, But in the neighbourhood of Babbaconribe, he says, there are several faults which at first sight olfe»; p very oiflerent character. Of these he Mentions two, that at Watcombeand another vi^est of Petit Tor rock. The first pre ^ents a vertical cliange of level of about 200 feet; but it is not, like the faults bcibi-e a' hi Jed to, rounded off, and therefore the author infers timt ir is of more recent ori-^in. Some observations a. e then oflered on ; he position of the trap in the neighbourhood of Babbacombe j and it is shown, t'lat in the hill to the east of ihe town it . ests on sliale, and is overlaid by beds of shale and limestone, tlie fraj) uippir^g to the south-west conformably with the stratified deposits. At its lower suiface it adheres firmly to the shale j but at its upper no such adhesion occurs, though the bed which rests upon the trap is moulded into its outline. From this phaeiornenon, and \\\q. absence of all marks of disturbance, the author infers, that the trap was a submarine lava current, ou which the superincumbent limestone and shale were subs.equently deposited. In other instances, however, as in the hill between Torquay and Tor Abbey, the limestone appears to have been violentl}^ disturbed, the beds of now red sandstone on the flanks of the hill being in a vertical position. In conclusion the author oft'ers some remarks on the drainage and destruction of the lake v.^hich he supposes to have occupied the site of the Ballemarsh and Bovey Heathfield. A paper, entitled, '< Some Facts in the Geology of the Central and Westei n Portions of North America, collected principally from the statements and unpublished notices of recent travellers," by Henry Darwin Rogers, Esq., F.G.S., was then begun. December 3rd. — The reading of Mr. Rogers's paper was resumed and concluded. Mr. Rogers states that he is indebted for the greater part of the facts contained in his communication to Mr. Sublette, a gentleman engaged for eleven years in the fur trade; but that he has also ex- tracted from the journals of Long and Lewis, and Gierke and Nutt- hall, such observations as bear upon the structure of the country. The district noticed includes the vast tractextendingfrom the Mis- sissippi to the Pacific, and from the S6th to the 49th degree of North latitude. The principal physical features of the country are the Rocky Mountains ; and the immense plains which extend from the Mississippi to that range, circle round its southern termination, and are prolonged into Mexico, and northward to an unknown distance. The Rocky Mountains consist, as far as they have been examined, of primary formations, and their eastern chain, the Black Hills, of gneiss and mica slate, greenstone, amygdaloid, and other igneous rocks. Chains of primary mountains, separated by sandy plains and volcanic tracts, constitute the country between the Rocky Mountains and the Pacific ; but to the east of that range are several nearly horizontal formations, of the limits or the^relative age of which lit- tle is known. The country from the falls of the Platte to the mountains, and from the Missouri to the Arkansas and the Rio Colorado, as well as the plains included within the Rocky Mountains, is composed of Geological Society, 65 a red saliferous sandstone, containing beds of cla}^ ; and Mr. Rogers is of opinion that the same formation extends into Mexico, and that the red sandstone described by Humboldt as occurring extensively in the southern parts of the continent, may belong to it. The ge- neral colour of the sandstone is red, but it is sometimes gray or white. The saline contents are principally muriate of soda, but other salts of bitter and cathartic properties likewise abound. Brine springs are of general occurrence ; and rock-salt is found in large beds west of the Rocky Mountains, as well as on the Rio Colorado, and south of the great Salt Lake. The surface of the ground, especially of the banks of the ravines, is often also thickly encrusted with saline matter. Gypsum is likewise found in many parts of the country. Fossils are said to abound in the sandstone on the river Platte, but Mr. Rogers states that he had not seen any of them. In the neighbourhood of the Rocky Mountains the formation is covered with a deposit of gravel and boulders, apparently derived from the adjacent hills ; but at a distance from them it is overlaid by a bed of loose barren sand, the drifting of which Mr. Rogers conceives may partially conceal the existence of other formations, especially of that greensand which occurs so extensively on the Missouri above the river Platte. At the eastern base of the Rocky Mountains and for a short di- stance up their declivity, are various conglomerates and gray and red sandstones, dipping at high angles ; but the author conceives that these deposits do not belong to the great sandstone formation, as they contain no salt. In ascending the Missouri from its confluence with the Missis- sippi the banks are in many places composed of limestone cliffs, 200 and 300 feet high, containing Productse, Terebratulae, and En- crini : hills of this limestone occur also near the Chariton; and in the same district is good bituminous coal. Above the junction of the Platte with the Missouri are beds of sandstone and dark blue shale, and a little higher, adjacent to the Au Jacque, are high, perpendicular bluffs of a formation con- sidered to be true chalk. This deposit extends for several miles up the Missouri, and it occurs further down the river about the moutli of the Omawhaw ; but its lateral extent is not known. No flints have yet been noticed in situ, but pebbles and nodules of flints, similar to those so abundant in the valley of the Thames, are numer- ous lower down the river, even as low as the Mississippi. Mr. Rogers likewise states that he had seen Belemnites reported to have been picked up in the same district. From below the Big Bend to the Rocky Mountains, both on the Missouri and the Yellow-stone river, is a vast formation, said to be very rich in fossils, indicating an upper secondary group ; and Mr. Rogers observes that the matrix in which the shells are imbedded resembles very closely some of the greensand-beds of Europe. The fossils mentioned in the paper are a Hamite, a Gryphaea con- sidered to be the Gryphcea Columba, and Belemnites compres&us. This formation has not been traced continuously over the whole area Third Series. Vol. 6. No. 31. J«w. 1835. K 66 Geological Socielt/. alluded to, but the same fossils have been brought from beds of the Missouri and Yellow-stone rivers, as well as from their springs in the Rocky Mountains j and they have been found west of that range. Above the Big Bend occurs also an extensive range of horizontal beds of lignite, sandstone, shale, and clay, forming bluffs 200 and 300 feet high, and continuous for several days' journey. Lignite is also found on the Cherry River, and along the whole of the country watered by the Powder River, in beds from 3 to 9 feet thick. This formation Mr. Rogers conceives to be more recent than that which contains the fossils, as the latter has a slight westerly dip, and there- fore may underlie it. Silicified trunks of trees are stated to have been noticed on the banks of the streams, and are considered by the hunters to have fallen from the bluffs. No recent volcanic production appears to have been yet brought from the country east of the Rocky Mountains, with the exception of the pumice which annually descends the Missouri -, but nothing is yet known of the quarter whence it is derived. West of the moun- tains, however, from the Salmon River to beyond Louis's River, and for a considerable distance around the insulated mountains called the Butts, the country is said to be composed of lava traversed by a multitude of deep, extensive fissures, having a general direc- tion from north-west to south-east, and nearly parallel to that of the mountains. Volcanic mounds, cracked at the top and surrounded by fissures, are numerous over the whole region j but no lava appears to have flown from them, and Mr. Rogers conjectures that they were formed by the action of elastic or gaseous matter. In many places deep circular funnels, a few yards in diameter, penetrate the sur- face. For more than 40 miles the Columbia runs between perpen- dicular cliffs of lava and obsidian, from 200 to 300 feet high, which are traversed by great fissures, and present all the phsenomena of dykes in the most striking manner. The Malador branch of the Columbia flows through a similar gorge. In the course of the memoir Mr. Rogers corrects the account pre- viously given of the great salt lake, which, he says, Mr. Sublette journied round, and ascertained to have no outlet, though it receives two considerable streams of fresh water. The length of the lake is estimated to be 150 miles and its breadth 40 or 50. In conclusion, some observations are offered on the thermal springs which abound along the base on each side of the Rocky Mountains, and in the volcanic district. They are stated to vary in temperature from blood heat to the boiling-point ; and to form, from their earthy contents, large mounds, sometimes of a pure white, hard, siliceous nature, and at others of a substance which on drying be- comes pulverulent. In the volcanic district some of the springs are said to be sour : and many sulphureous springs occur both in and west of the mountains. Lastly, pure sulphur has been occasionally seen above the Great Salt Lake, and at the eastern base of the mountains, but none in the volcanic district* Geological Society 67 A letter was then read from H. T. De la Beche, Esq., F.G.S., and addressed to the President, on the Anthracite found near Biddeford in North Devon. Mr. De la Beche says, the anthracite occurs along a strip of country about thirteen miles in length from east to west and about three quarters of a mile in breadth from north to south. It com- mences eastward at Hawkridge Woods on the banks of the Taw, and extends westward to Greencliff in Biddeford Bay, where the sea cuts off all further observation of its course in that direction. On the opposite side of the bay, however, a very carbonaceous slate is found in the cHfFs among the greatly contorted strata of grauwacke between Clovelly and Hartland Point. There can be little doubt, Mr. De la Beche observes, that this carbonaceous slate belongs to the same system as the Biddeford beds, and thus it would be extended about eleven miles still further westward, where the sea again cuts it off. The anthracite between Hawkridge and Greencliff has been extensively worked at various times, and at the latter place is now worked for the sole supply of a limekiln. The beds of anthracite do not occur precisely in the same line with each other, so that one or two beds are not so far continuous, but swell out in particular places, the maximum thickness not exceed- ing 12 feet. The letter was accompanied by a collection of fossil plants, all collected by Mr. De la Beche ; and he says there can be no question that the shales, slates, sandstones, and anthracite, among which they are found, belong to the grauwacke, the evidence being of the most clear and satisfactory kind*. With regard to the position of these beds in the grauwacke of Devon generally, it may be considered at about two thirds of the whole, above that part where the grauwacke shades away into the mica slate, chlorite slate, and other non-fossiliferous rocks of the most southern part of Devon. It should, however, be observed that the grauwacke of Devon and Somerset is not complete, and that we nowhere can see what can be decidedly termed its upper por- tions. After very diligent search, Mr.Dela Beche observes, he has been unable to discover any of the interesting beds of the upper grauwacke noticed by Mr. Murchison in Wales or the adjoining English counties. On the north coast of Devon and its continua- tion into Somersetshire, precisely where some traces of them should be expected, older beds are brought up by contortion (Dunkeny Beacon), and the other high land of the coast is formed of beds apparently of the same age with those which extend from Hartland to the eastward, a great trough being formed, supporting a body of * The plants have been examined by Prof. Lindley,and he has decided that they are, as far as they can be determined, plants of the coal measures, viz. Fecopteris lonchiticay Sphenopteris latifolia, Catamites cannceforviiSy As- terophyllites resembling A. longifolia^ another species, which maybe A.ga- lioidisy Cyperites bicamiata, and Lepidopht/lhim intermedium ; also frag- ments apparently of Palm leaves, specimens of which Prof. Lindley states he has received from Bolton. The most abundant plant was too imperfect for its characters to be determined. K 2 68 Zoological Society, grauwack6, the chief portion of which is an argillaceous slate^ cal- careous matter being disseminated in the lowest portion of it, often in sufficient abundance to constitute limestone. A paper was afterwards commenced on the physical and geologi- cal structure of the country to the west of the dividing range between Hunter's River (lat. 32° south) and Moreton Bay (lat. ti7° south), with observations on the geology of Moreton Bay and Brisbane River, New South Wales, by Allan Cunningham, Esq., and com- municated by William Henry Fitton, M.D., F.G.S. ZOOLOGICAL SOCIETY. [Continued from vol. v. p. 385.] August 12. — A Letter was read, addressed to the Secretary by B. H. Hodgson, Esq., Corr. Memb. Z. S., and dated Nepal, Feb- ruary 28, 1834. It related chiefly to the distinguishing characteris- tics between the Ghoral and the Thdr Antelopes, and an abstract of it is published in the Proceedings. The exhibition was resumed of the new species of Shells con- tained in the collection formed by Mr. Cuming on the W^estern Coast of South America, and among the Islands of the South Paci- fic Ocean. Those exhibited on the present evening consisted of various species of Anatinida and of the Myidous genus Saxicava : they were accompanied by characters by Mr. G. B. Sowerby, and were named as follows : Periploma lenticularis , ?ind planius aula; Anatina prismatica, and costata; IiYONSIA picta, and brevifrons; Saxicava tenuis purpurascens, and solida. A collection of land and fresh-water Shells, formed in the Gangetic Provinces of India by W. H. Benson, Esq., of the Bengal Civil Sendee, and presented by that gentleman to the Society, was ex- hibited. It comprised forty species, and was accompanied by a de- scriptive list prepared by the donor, and also by detailed notices of some of the more interesting among them. These notices were read : they are intended by Mr. Benson for publication in the forth- coming No. of the ' Zoological Journal.' From the time that he first became acquainted with the animal of a Shell resembling in all respects, except in its superior size, the European Helix lucida, Drap., Mr. Benson regarded it as the type of a new genus of HelicidtB intermediate between Stenopus, Guild., and Helicolimax, Fer. He had prepared a paper on this genus, for which he intended to propose the name of Tanychlamys ; he finds, however, that Mr. Gray has recently described (Lond. and Edin. Phil. Mag. vol, V. p. 379.) the same genus under the name of Nanina. ITie generic characters observed by Mr. Benson are as follows : Nanina, Gray. Testa heliciformis, umbilicata ; peritremate acuto, non reflexo. Animal cito repens. Corpus reticulosum, elongatum. Pallium amplum, foramine communi magno perforatum, peritrema amplex- ans ; processubus duobus transverse rugosis (quasi articulatis) omni latere mobilibus instructum, unico prope testae aperturse angulum superiorem exoriente, altero apud peripheriam testae. Zoological Society. 69 Os anticum inter tentacula inferiora hians; labia radiato-plicata. Tentacula saperiora elongata, punctum percipiens tumore oblongo situm gerentia. Penis prsegrandis ; antrum cervicis elongatum la- tere dextro et prope tentacula situm. Solea complanata pedis latera a^quans. Cauda tentaculata ; tentaculum subretractile, glandula ad basin posita humorem viscidum (animale attrectato) exsudante. Mr. Benson describes particularly the habits of the species ob- served by him, which he first discovered living at Banda in Bundel- kund on the prone surface of a rock. The animal carries the shell horizontally or nearly so ; is quick in its motions ; and, like Heli- colimax, it crawls the faster when disturbed, instead of retracting its tentacula like the Snails in general. In damp weather it is rarely re- tracted within its shell, the foot being so much swelled by the ab- sorption of moisture that if it is suddenly thrown into boiling water the attempt to withdraw into the shell invariably causes a fracture of the aj)erture. In dry weather the foot is retracted, and the aper- ture is then covered by a whitish false operculum similar to that of other Helicidce. The two elongated processes of the mantle are con- tinually in motion, and exude a liquor which lubricates the shell, supplying, apparently, that fine gloss which is observable in all re- cent specimens. The fluid poured out from the orifice at the base of the caudal horn-like appendage is of a greenish colour ; it exudes when the animal is irritated, and at such times the caudal appen- dage is directed towards the exciting object in such a manner as to give to the animal a threatening aspect. Of several specimens brought to England by Mr. Benson in 1832, one survived from December 1 83 1 , when it was captured in India, until the summer of 1833. Another Shell particularly noticed by Mr. Benson is the type of a new genus, allied to Cyclostoma, which he has described under the name of Pterocyclos in the first No. of the * Journal of the Asi- atic Society of Calcutta.' Specimens of a species of Assiminia, Leach, were preserved alive in a glass, replenished occasionally with fresh or salt water, until after the vessel in which Mr. Benson returned to England had passed St. Helena. A Snail obtained near Sicrigali and the river Jellinghy, one of the mouths of the Ganges, is characterized by Mr. Benson as Heux interrupta. In the character of the excrement being voided from an opening in the terminal and posterior part of the foot instead of from the foramen commune, the animal of Hel. interrupta differs most ma- terially from the other Helices. The angulated periphery of the shell shows an approach to Carocolla, but Mr. Benson is not aware that the animal of this genus diflTers from that of Helix. From Hel. Hima- layana. Lea, the Hel. interrupta is distinguished by its peculiar sculpture ; its spire is also more exserted. The collection also contained specimens of an Arcaceous Shell found in the bed of the Jumna at Humeerpore in Bundelkund. Mr. Benson proposes for it the generic appellation Scaphula. 70 Zoological Society. Referring to specimens contained in the collection of a new form of Solenaceous Shell, described by him in the ' Journal of the Asi- atic Society of Calcutta/ under the name of Novaculina, Mr. Ben- son describes also a second species of the genus which he has recently obtained from South America, and points out the characters which distinguish it from Nov. Gangetica. The following Note by Mr. Benson relative to the importation of the living Cerithium Telescopium, Brug., adverted to at the Meeting on March 25, 1834, (vol. v. p. 145,) was read. " The possibility of importing from other countries, and especially from the warmer latitudes, the animals which construct the innu- merable testaceous productions that adorn our cabinets and mu- seums, the accurate knowledge of which is so necessary to enable the conchologist rightly to arrange this beautiful department of na- ture, must be an interesting subject to every naturalist, and will render no apology necessary for the following notices extracted from my journal. Their publicity may incite others who may have op- portunities of trying the experiment to follow the example. " January 1832. Observed near the banks of the canal leading from the eastern suburb of Calcutta to the Salt Lake at Balliaghat, heaps of a Cardita with longitudinal ribs, of a large and thick Cy- rena, and of Cerithium Telescopium, exposed to the heat of the sun for the purpose of effecting the death and decay of the included ani- mals previously to the reduction of the shells into lime. " Early in the month I took specimens of them, and leaving them for a night in fresh water I was surprised to find two Cerithia alive. I kept them during a fortnight in fresh water, and on the 22nd January carried them, packed up in cotton, on board a vessel bound for England. After we had been several days at sea I placed them in a large open glass with salt water, in which they appeared un- usually lively. I kept them thus, changing the water at intervals, until the 29th May, when we reached the English Channel. I then packed them up, as before, in a box, and carried them from Ports- mouth to Cornwall, and thence to Dublin, which I did not reach until the 14th June ; here they again got fresh supplies of sea wa- ter at intervals. One of them died during a temporary absence be- tween the 30th June and 7th July ; and on the 11th July the sur- vivor was again committed to its prison, and was taken to Cornwall and thence to London, where it was delivered alive to Mr. G. B. Sowerby on the 23rd July. '* This animal had thus travelled, during a period of six months, over a vast extent of the surface of the globe, and had for a con- siderable portion of that time been unavoidably deprived of its native element." — W. H. B. At the request of the Chairman, Mr. Heming exhibited a Swift, Cypselus Apus, 111., preserved in spirit, and showing a consider- able dilatation at the base of the lower jaw and upper part of the throat. White has observed that " Swifts, when wantonly and cruelly shot while they have young, discover a lump of insects in their mouths, which they pouch and hold under their tongue ;" Zoological Society. 71 but from this notice it would scarcely have been anticipated that so large a collection was made as was found in the present instance. The dilatation had a rounded appearance ; distended the skin so as to show distinctly and widely separated the insertion of each of the small feathers at this part ; and measured in length 1 1 lines, and in depth 6. On opening the pouch it proved to be simple, and unconnected except with the cavity of the mouth. Mr. Heming also exhibited a drawing taken from the recent bird. Dr. Marshall Hall showed some experiments in the decapitated Turtle. Irritation of the nostrils, larynx, and spinal marrow induced acts of inspiration ; that of the fins and tail induced movements of the other parts respectively. But the principal object of Dr. Hall was to show that irritation of the nerves themselves equally induced movements of the limbs, &c. When either the sentient or the motory branch of the lateral spinal nerves was stimulated, motions were induced in all the limbs. Dr. Hall stated that a movement of inspiration and of deglutition was caused in the Donkey by irritation of the eighth pair of nerves. It has been already stated that irritation of the nostrils, or the branches of the fifth pair of nerves, induced inspiratory acts in the Turtle. From these and other facts. Dr. Hall is induced to consider the functions of these two nerves as similar. He further observed that both are nerves of secretion, and that both are muscular nerves — if the minor portion of the fifth be included — as well as exciters of respiration : the fifth differs chiefly in being sentient, being dis- tributed to external as well as internal surfaces. With the fifth and eighth. Dr. Hall associates other spinal nerves. He considers re- spiration as a part of a general function of the nen'^ous system, which presides over the larynx, pharynx, sphincters, ejaculators, &c., to which he has given the name of reflex, from its consisting of im- pressions carried to and from the medulla oblongata and medulla spinalis. Some illustrations of this function were given by Dr. Hall at the Meeting of the Committee of Science and Correspondence on November 27, 1832, (Lond. and Edinb. Phil. Mag. vol. ii. p. 477,) and further illustrations of it have formed the subject of a Paper by him, which has since been published in the ' Philosophical Transactions'. 7'he experiments shown on the present occasion demonstrate the existence of a series of physiological facts at variance with the law laid down by M. Miiller in his Paper entitled " Nouvelles Experi- ences sur I'eff^et que produit 1' Irritation mecanique et galvanique sur les racines des nerfs spinaux ; par Jean Miiller, Professeur a I'Uni- versite de Bonn," and published in the * Annales des Sciences Na- turelles, ' tom. xxiii. (1831), p. 95, viz. " II suit encore qu'il y a des nerfs qui n'ont point de force motrice ou tonique, qui ne peuvent jamais occasionner des mouvemens par eux-meraes, qu'ils soient ir- rites par Taction galvanique ou mecanique, et qui ne conduisent le courant galvanique que passivement, comme toutes les parties molles humides ; qu'il y a en revanche des nerfs moteurs ou toniques (nervi motorii seu tonici) qui montrent ^ chaque irritation mediate ou im- mediate leur force tonique, qui agit toujours dans la direction des 72 Linnaran Society, branches des nerfs et qui n'agit Jamais en arriere.*' In Dr. Hall's experiments the influence first pursued a backward course to the spinal marrow, being afterwards reflected upon the muscles. Dr. Hall next observed, in regard to respiration, that, whilst Sir Charles Bell is contending that it is involuntary, and Mr. Mayo that it is voluntary, the old doctrine of its being mixed, or partaking of both properties, is the true one. He founded this view upon the following facts : 1 . If the cerebrum be removed, respiration continues as an invo- luntary function through the agency of the eighth pair of nerves ; 2. If the eighth pair be divided, respiration equally continues, but as an act of volition ; but 3. If the cerebrum be first removed, and the eighth pair be then di- vided, respiration ceases on the instant. Volition is first removed with the cerebrum ; the influence of the eighth pair is then removed by its division. The two sources of the mixed or double function being both cut off, the function ceases. Dr. Hall explains and reconciles in this manner the difficult and apparently contradictory facts, — that the medulla oblongata alone, above the origin of the eighth pair of nerves, or the eighth pair of nerves themselves, may be divided, without arresting the respira- tion ; but that the medulla oblongata cannot be divided at the origin of these nerves without arresting the respiration instantly. In the first case the agency of volition is alone removed, and the respira- tion continues through the influence of the eighth pair; in the second, that of the eighth pair is removed, and the respiration con- tinues as a function of volition ; but in the third, both influences are destroj'^ed at once, and with them the mixed or double function. The same mixed or double character belongs to the other parts of the reflex function, as that of the larynx, the sphincters, the eja- culators. All the organs of the reflex function are also alike im- pressed through the medium of the mental aff^ections or passions. The course of the influence which constitutes the reflex function must be divided into the incident, or that into the medulla, and the reflected, or that from the medulla. The nerves which conduct the incident impression have, hitherto, received no designation ; the others constitute a part of the system of muscular nerves. To the former class belong nerves which doubtless supply the larynx with its impressibility by carbonic acid, &c., &c., and hitherto unde- scribed, untraced ; to the latter, the superior and inferior laryngeals : to the former belong the fifth, in the nostrils, in the face, — the eighth in the lungs, &c. ; to the latter, the respiratory nerves : to the former, nerves hitherto undescribed of the sphincters, ejacula- tors, &c. ; to the latter, the muscular nerves supplying these parts. The whole constitutes the subject of an investigation in which Dr. HaU has been for some time engaged. LINN^EAN SOCIETY. Nov. 4-. — Read descriptions of some additional species of the Dipterous genus Diopsis, by John O. Westwood, Esq., F.L.S. j and Cambridge Philosophical Society. 73 the commencement of a paper on the Nervous System of the Mol- lusca and lladiata, by Robert Garner. Nov. 18. — A continuation of Mr. Garner's paper on the Nervous System of the Radiated and Molluscous Animals was read. Dec. 2. — A paper was read on a new Arachnide, uniting the genera Goryleptes and Phaiangium, by the Rev. F. W. Hope, M.A., F.L.S. This insect, which is remarkable for the great disproportionate length of its hinder legs, forms a new genus, which Mr. Hope has named Dolichoscelisy and the species he has named Haworthii, in honour of the late Mr. Haworth, in whose collection the specimen had long been. It is a native of Brazil. Read also part of a paper, entitled, *' Descriptions of the Insects collected by Capt. P. P. King, R.N., F.R.S. & L.S. in his Survey of the Straits of Magellan." By John Curtis, Esq., F.L.S. j A. H. Haliday, Esq., M.A. ; and Francis Walker, Esq., F.L.S. Dec. 16. — The conclusion of Mr. Garner's paper was read. CAMBRIDGE PHILOSOPHICAL SOCIETY. The Anniversary Meeting was held on November the 6th, for the election of officers, when the following gentlemen were elected for the ensuing year: President: — Joshua King, Esq., President of Queen's Coll., (re- elected).— Vice-Presidents: Dr. Clark, Trinity, (re-elected); Prof. Airy, Trinity, (re-elected); Prof. Miller, St. John's, (re-elected). — Treasurer : Rev. G. Peacock, Trinity. — Secretaries : Rev. W. Whe- well. Trinity, (re-elected) ; Rev. J. S. Henslow, St. John's, (re- elected) J Rev. J. Lodge, Magdalen Coll., (re-elected.) — Old Council: Rev. R. Willis, Caius Coll.; Dr. Bond, C. C. C; Rev. J. Bowstead, C. C. C; W. Hopkins, Esq., Pet. Coll.; Rev. T. Che- vallier, Cath. Hall; Rev. J. Hymers, St. John's. — Nevo Council: Prof. Sedgwick, Trinity ; Dr. Haviland, St. John's ; Rev. J. J. Smith, Caius Coll. ; Rev. S. Earnshavv, St. John's. Nov. 10. — Professor Airy, V.P., in the Chair. Many presents were produced and noticed, among which was the magnificent vo- lume of the experiments of Col. Beaufoy, printed for private distri- bution by his son ; and the Cambridge Observations for 1833, which now include regular observations with the mural circle as well as with the transit instrument. Several specimens of Fish, sent from Madeira by Mr. Lowe, were also presented ; and a paper by him was read, containing a description of six new or very rare species. Mr. Whewell gave an account of the Tide Observations made at the Coast Guard Stations of the British Isles, from June 7 to June '2,2, of the present year; he also stated the mode in which he was dis- cussing the observations, and the results to which they seemed likely to lead. Nov. 24 Prof. Airy, V.P., in the Chair. Prof. Airy gave an account of the calculations which he had caused to be made in order to determine the apparent disk of a star, and the rings which surround it, when seen through an object-glass with a circular aper- Third Series. Vol. 6. 2Vo, 3 I . Jan. 1835. L 7 i Cambridge Philosophical Society, turc. He also stated that corrections had recently been discovered to be necessary in the results of the Trigonometrical Survey of this county, by which thp differences which had previously appeared to exist between the astronomical andgeodetical determinations of the latitude and longitude of Cambridge Observatory are greatly dimi- nished. Mr. Stevenson, of Trinity College, read a memoir on the esta- blishment of the formulae of Analytical Geometry by the combination of the infinitesimal method with the doctrine of projections. Prof. Sedgwick and other members then communicated some observations illustrative of the geology of Cambridge. The upper chalk with flints runs in a distinct terrace from near Newmarket, by Balsham and Linton, to Royston Downs, and thence into Hertfordshire. Beneath this is the lower chalk without flints, which runs from Reach to Cherryhinton and Haslingfield. Below this is a thin bed, which re- presents the upper greensand, and which, though not above a foot and a half thick, is remarkably continuous in the neighbourhood of Cambridge, being found at the Castle Hill, Barnwell, Ditton, Coton, and Modingley. Under this are the blue gait and the " lower green- sand" of geologists, which may here be called the red-sand. The red-sand runs from Gamlingay and Caxton, by Conington, Long- stanton, Cottenham, and Upware. But the junction of the gait and red-sand is covered up on the west of Cambridge by a large diluvial patch of " brown clay," which is full of rounded nodules of chalk. This brown clay forms an upland, which extends from Bourne, by Toft and Hardwicke, to Dry Drayton, after which it soon drops into the plain; but the junction of the strata in the plain is still co- vered up with ferruginous gravel as at Okington. Below the red- sand occur other clays, easily confounded with the gait, but iden- tified with the Kimmeridge and Oxford clays by their fossils ; these are found at Graijsden, Cottenham Fen, and Ely. It was stated that the relations of the successive formations are very obscurely exhibited, in consequence of the strata and their junctions being masked by diluvial masses. Dec. 8. — Prof. Airy, V.P., in the chair. Prof. Miller read a memoir on the position of the Optical Axes of Crystals. Prof. Henslow noticed some newly observed localities of the (upper) green-sand in the neighbourhood of Barton and Haslingfield. He then made some remarks on De Candolle's rules for determining the age of trees, and mentioned some instances which he had noticed during the preceding summer, in which they did not apply in the case of the yew. He conceived that these rules, when applied to several well known yew-trees in Britain, must give the age considerably too great. Prof. Airy mentioned the echo which is returned by the open end of the tall chimney recently erected at Barnwell gas-works. Prof. Gumming then gave a statement of Melloni's discoveries on the transmission of heat by radiation through glass and crystallized bodies, illustrated by apparatus and experiments. [ 75 3 X. Intelligence and Miscellaneous Articles. ROYAL MEDALS TO BE AWARDED BY THE COUNCIL OF THE ROYAL SOCIETY, FOR THE MOST IMPORTANT DISCOVERIES AND INVESTIGATIONS IN SCIENCE, IN THE YEARS 1836 AND 1837. TN order to perform our part in giving publicity to the determi- -■- nations and intentions of the Councilor the Royal Society with respect to the Royal Medals, we extract the following notice from the second part of the Philosophical Transactions for 1834, which has just appeared, " Royal Medals.— Uk Majesty King William the Fourth, in re- storing the Fountlation of the Royal Medals, graciously commanded a letter, of which the following is an extract, to be addressed to the Royal Society, through His Royal Highness the Duke of Sussex, K.G., President : « * Windsor Castle, March 25, 1833. " * It is His Majesty's wish, — '' * First, That the Two Gold Medals, value of Fifty Guineas, shall henceforth be awarded on the day of the Anniversary Meet- ing of the Royal Society, on each ensuing year, for the most im- portant discoveries in any one principal subject or branch of knowledge. " * Secondly, That the subject matter of inquiry shall be pre- viously settled and propounded by the Council of the Royal So- ciety, three years preceding the day of such award. " ' Thirdly, That literary men of all nations shall be invited to afford the aid of their talents and research : and, ** * Fourthly, That for the ensuing three successive years, the said Two Medals shall be awarded to such important discoveries, or series of investigations, as shall be sufficiently established, or completed to the satisfaction of the Council, within the last five years of the days of award, for the years 1834 and 1835, including the present year, and for which the author shall not have pre- viously received an honorary reward." ' " (Signed) ' H. Taylor.' " The Council propose to give one of the Royal Medals in the year 1836, to the most important unpublished paper in astronomy, communicated to the Royal Society for insertion in their Trans- actions, after the present date and prior to the month of June in the year 1836. " The Council also propose to give one of the Royal Medals in the year 1836 to the most important unpublished paper in Animal Physiology, communicated to the Royal Society for insertion in their Transactions, after the present date and prior to the month of June in the year 1836. " The Royal Medals for the year 1833 were awarded to Sir John Frederick William Herschel, K.H., F.R.S., for his paper on the Investigation of the Orbits of Revolving Double Stars ; and to Pro- fessor Augusto Pyramc Dc CandoMc, of Geneva/ Foreign Member L2 76 InlelUge7ice and Miscellaneous Articles. of the Royal Society, for his Discoveries and Investigations in Ve- getable Physiology. *' Those for 1834 were awarded to John William Lubbock, Esq., V.P. and Treas. R.S., for his Papers on the Tides published in the Philosophical Transactions; and to Charles Lyell, Esq., for his Work entitled ' Principles of Geology.' " The Council propose to give one of the Royal Medals in the year 1837 to the most important unpublished paper in Physics, com- municated to the Royal Society for insertion in their Transactions, after the present dale and prior to the month of June in that year. " The Council also propose to give one of the Royal Medals in the year 1837 to the author of the best paper, to be entitled * Con- tributions towards a System of Geological Chronology founded on an examination of fossil remains, and their attendant phaenomena,' such paper to be communicated to the Royal Society after the pre- sent date and prior to the month of June 1837." ON THE OCCURRENCE OF FRAGMENTS OF GARNET IN THE MILLSTONE-GRIT. BY W. C. TREVELYAN, ESQ. To the Editors of the Philosophical Magazine and Journal of Science. Gentlemen, About the year 1 826, 1 found dispersed rather abundantly in parts of the millstone-grit rock of Shaftoe in this neighbourhood, small, angular, transparent fragments of garnet : since that time I have met with them in similar rocks of the coal-fields near Kirkstall in York- shire, and Stirling in Scotland, and think that on further exami- nation they may be more extensively observed, as it is probable that these rocks have been formed from the detritus of others, which are known sometimes to contain garnets in great abundance, as well as the other parts of which the millstone-grit is composed, among which I have also occasionally found small rolled fragments of hornblende. I shall be glad if you think this notice worth printing in your Journal, for the purpose of drawing the attention of geologists to the subject : And remain. Gentlemen, Your most obedient, Wallington, Newcastle- on-Tyne, W. C. Trevelyan. 29th September. MINERALOGICAL NOTICES. BY H. J. BROOKE, ESQ. F.R.S. &C. To the Editors of the Philosophical Magazine and Journal of Science, Gentlemen, I shall be obliged by your inserting the following mineralogical notices in the next Number of your Journal. Gentlemen, yours, &c. H. J. Brooke. I have stated in the Philosophical Magazine and Annals, N.S. vol. x. p. 190, that zurlite and wollastonite are the same substance, a mistake into which I was led by having observed several speci- Intelligence and Miscellaneous Articles. 77 mens of wollastonite ticketed zurlite. I have lately been favoured by Mr. Monticelli with specimens of zurlite^ a green mineral, and bearing no resemblance to wollastonite, or to any specimen I have before observed. The late Mr. Phillips, in his Elements of Mineralogy, gave a figure of a supposed crystal of the flexible silver of Bourn on, dif- fering altogether from Bournon's figures. The specimen from which that crystal was taken was said to be Bournon's mineral; it is, how- ever, sulphuret of silver, and the figure given by Mr. Phillips is evidently a distorted modified cube. I have lately obtained a specimen of Bournon's flexible silver, so named by himself, from which it appears to be the same mineral as the sternbergite of Haidinger. Mr. Phillips also gave a figure of xuhite tellurium from a crystal he received from me. It is not, however, certain that this crystal is the mineral commonly so named. It is very minute and brilliant, and silver white, and there are many similar to it in the cavities of a small group, in my possession, of very distinct crystals of foliated tellurium, one of which was also figured by Mr. Phillips. Perhaps, among the larger collections of the ores of tellurium, these white crystals may occur in sufficient quantity for chemical examination. ON THE JUICE OF ESCHSCHOLZIA CALIFORNICA. Not being aware that any scientific author has made mention of the very peculiar jwfce contained in tha;t beautiful plant the Californian Eschscholzia, I beg to call the notice of the medical and chemical readers of the Philosophical Magazine to this point. The juice is of a yellowish colour, and is given out very readily from the stems and other parts of the plant ; it smells exactly like muriatic acid, and possesses in some degree the property of taking out ink-spots from linen, &c. This plant is a species of the new genus Eschscholzia, belonging to the natural order Papaveracece ; and, like some of the same order, the common Celandine (Chelidonium majus) and the Opium Poppy (Papaver somniferum), for instance, it has a similar powerful juice, which 1 think probably may hereafter, hke theirs, become of use to the physician, as well as of service to the chemist. For this reason, may I beg that the Editors will give these lines a place in their Magazine ; hoping that as the Eschscholzia Cali- Jbrnica is now common in many of our gardens, a chemical analysis of its strong juice, and the experiments consequent thereon, may develop the causes of its muriatic-acid-like scent, and perhaps ren- der it beneficial in medicine. London, Dec. 3, 1834. ' J. H. N. ANALYSIS OF NADELERZ. BY HERRMANN FRICK. The mineral examined was found in the gold veins of Beresow in the Ural, hitherto the only known locality of it. It occurs com- monly disseminated in quartz in very slender acicular prismatic crystals, deeply striated, and exhibiting an imperfect cleavage pa- 78 Intelligence and Miscellaneous Articles, rallel to the principal axis. Its colour When recently fractured is dark lead grey with metallic lustre, which gradually changes to brown. Specific gravity 6*757. The results of two different analyses are as follows : Corresponding Corresponding proportion of proportion of Sulphur.. 16-05 Sulphur. 16-61 Sulphu Bismuth.. 34.-62 785 3S-4.5 8-26 Lead 35-69 5-57 36-05 5-60 Copper .. 11-79 2-96 10-59 2-69 lur. 9815 16-38 99-70 16-55 Poggendorffy band xxxi. § 529. Hence in the composition of nadelerz there are three atoms of bismuth, two of lead, and one of copper, combined respectively with one of sulphur. AMMONIA IN THE VEGETABLE ALKALIES. M. Matteucci remarks that the existence of azote and hydrogen in the form of ammonia in the vegetable alkalies, is one of the points respecting which there is yet uncertainty. According to the ana- lysis of Liebig, the relation between the acid and the azote of the base, is exactly the same as in ammoniacal salts ; and the vegetable alkalies, like ammonia, form true salifiable bases only when combined with water; and lastly, the salts which have a vegetable alkali for their base, are similar to ammoniacal salts as to isomorphism with other salts : from these circumstances M. Matteucci concludes that apart at least of the azote of these alkalies is in the state of ammonia. It will be readily admitted that voltaic electricity offers the most • proper method of solving the question ; for this purpose it is suffi- cient, though difficult of execution, to apportion the force of the electric current so as to separate the binary compounds without transforming them. For this purpose an apparatus, precisely simi- lar to that used by M, Becquerel, was employed, and some pure iiarcotine was put upon a slip of turmeric paper moistened with aether: the same was also done with reddened litmus paper. Although the alkaline nature of narcotine is well ascertained, yet it is well known that it does not produce the same effects as other alkalies upon the colours of turmeric and reddened litmus.' After some time the blue colour of the litmus reappears, and the turmeric is reddened. Still further to investigate this subject, sulphate of cop- per, in very fine powder, was mixed with pure morphia and placed on paper moistened with alcohol, which touched the copper of the small pile; in a few minutes the mixture became blue : this experi- ment succeeded also when a pile of ten pairs was employed. As it is impossible to believe that this ammonia is formed by the com- bination of the azote and hydrogen developed by the pile, the exist- ence of this body in a state of combination in the organic alkalies must be admitted. — Ann. dc C/tim, cl dc Phys. torn. Iv. p. 317. Intelligence and Miscellafieous Articles, 79 ON THE EMPLOYMENT OF INSOLUBLE SALTS IN ANALYSIS. BY M. HORACE DEMAR^AY. One class of metallic oxides is characterized by its want of power to saturate acids perfectly, and by the property of not dissolving in these agents unless they are in excess. The oxides of iron, chro- mium, tin, bismuth, and antimony, as well as the oxides of the electro-negative metals, belong to this class. It is possible to precipitate these oxides without the intervention of any powerful affinity. The carbonates of lime, barytes, strontia, or magnesia, when added to a cold solution of peroxide of iron, separate it so completely that the most sensible reagents indicate no trace of it. In this way the peroxide of iron may be separated from the prot- oxide, and also from the oxides of manganese, cobalt, or nickel, with more facility and accuracy than by any other method. The car- bonates of barytes and strontia are to be preferred, on account of the facility with which they are separated from the fluid in which they are dissolved, or from the peroxide of iron with which they are mixed. This process is excellent for procuring oxide of cerium entirely free from peroxide of iron. Oxide of bismuth acts like peroxide of iron ; carbonate of barytes separates it cold and perfectly from per- oxide of copper; lead, manganese, and nickel may be separated in the same manner. Carbonate of barytes precipitates in the same manner the oxides of antimony and peroxide of tin from solution in muriatic acid, and it may be employed to separate lead from copper, which are united in many alloys. The protoxide of tin is not separated by carbonate of barytes ; this process may, therefore, be used to sepa- rate tin from antimony. Oxide of chromium acts like peroxide of iron with carbonate of barytes ; this metal may, therefore, be se- parated by it from the oxides of nickel, cobalt, manganese, and those which have been mentioned when treating of peroxide of iron. If the solution contains peroxide of iron, that will be preci- pitated with the oxide of chromium, and they may be separated by calcination with potash. In order to separate iron from chromium, when both are dis- solved in an acid, it is sufficient to saturate the liquor with sulphu- retted hydrogen in order to reduce the iron to the state of protoxide, and then the carbonate of barytes precipitates the oxide of chromium only. Both oxides of mercury, when dissolved in nitric acid, are preci- pitated, like the oxide of bismuth, by carbonate of barytes. The carbonates of the alkaline earths have been proposed to separate different oxides ; but the proposal has not met with the attention which it deserves, because the most important circumstance has not been sufficiently observed, which is, the temperature at which the precipitation ought to be effected. The action of these salts varies at different temperatures. Thus, the muriates and nitrates of cobalt, nickel, manganese, zinc, and copper are entirely decomposed by the carbonates of lime and magnesia, but only at a certain tem- perature. Copper and zinc are precipitated first, cobalt and nickel afterwards, manganese the last; but these metals cannot be se- parated from each other by this method. — Journal de Pharmacie, October 1834. ^*S tl dJ M 1! n 3 O fe 'cS "^^ -o ^ 'o ■^ c 2i^ •^ a « ^-i^'.S ?r A, p, — • 5^ o5 c»-i ?^>^, tf^'SS be „ OJ T3 ^ " S "" 3 £ = •5 W)-3 .2 c ^ CO cS >~> . ii „ ^ ^ £■•§ 2'^ ^ Go3 QJ CO H a, r; aj 03 OT ^ .Si c oj j= ca o >- c t: c I ^ ^ • S ? rt • ^ 5 E .U tt> • ■2 C a; . c «> O t- "• ^ x6 < •isog I 'puoq nsog o o o u o o sssaa .ssssss •puoq ^ S:* BS ^* 6t ^' «; ^* c^ w w . w w M ^ ^ W t: >5 SC 55 .: w •R^fg ^o»noom^ocr5^oc^^o'loot^cocolO*ooooo■^c^c^GOvolOloa^rM^ o— .-^oo■rf^o^e^^~o»r5r50^0l— •ooc^o^oo<^^c^ — OOO^ipvOTtT*'^Qp-;S^O^OOOOO,OOOOOC>6^^Oo6^0^6^O^6^6^ o THE LONDON AND EDINBURGH PHILOSOPHICAL MAGAZINE AND JOURNAL OF SCIENCE. -♦- [THIRD SERIES.] FEBRUARY 1835. XI. Oil the Practicability of alloying Iron and Copper, By David Mushet, Esq, To Richard Phillips, Esq., F,R.S. L, SrE. Src. Sill, TN perusing the other day Dr. Lardner's third volume on ^ metals*, I met v^^ith the following unqualified assertion : "As to alloying copper with iron, the notion not only appears absurd, but unsupported by evidence." As at the present moment Dr. Lardner's publication may be considered a text- book of popular instruction, such a statement might lead to a settled conclusion that to alloy iron and copper is under all circumstances impossible. Now the contrary is the fact ; and having considered this operation for many years as one which, if happily effected, would materially contribute to the perfec- tion of many of our mechanical contrivances, I hope I shall be excused for entering on the subject somewhat particularly. In the first place, I see no prima facie reason why it should be absurd to expect that iron should unite with copper as well as it does with other metals. Then as to the evidence, I think that most chemical works state the fact as a matter of course, never doubting the practicability of the measure ; and in your own Magazine, vol. xlix., I find some experiments on the union of iron with copper; which shows that the subject has not been recently altogether overlooked. The uncertainty which prevails upon the subject arises from the want of accu- • " Manufactures in Metal, vol. iii. Tin, Lead, Copper, Brass, Gold, Silver, and various Alloys," p. 174. Third Sei'ies, Vol. 6. No. 32. Feb. 1835. M 82 Mr. D. Mushet on the Alloys of Iron ajid Copper. racy in defining the nature and quality of the iron which has been the subject of the union. Most of the books entirely over- look the various states of iron, and fail to distinguish whether the subject-matter of the experiment was cast iron, or steel, or iron in a state of malleability. The same remark applies to the experiments of Mr. P. N. Johnson as above, who, though he states that he effected an union between iron and copper, yet leaves it doubtful whether the iron was not steel or cast iron instead of pure or malleable iron. The well-known affinity of iron for carbon precludes the possibility of malleable iron being heated and melted in contact with a large dose of char- coal (as was the case in his experiments,) without its passing into the state of steel or cast iron. So that the experiments of Mr. Johnson may be considered as representing, not the union of copper with wrought or malleable iron, but with cast steel or crude iron. Whether or not these were examples of a real chemical alloy, or of a mere mechanical mixture, maybe gathered from the following remarks, which are grounded on an extensive series of experiments. It had for many years appeared a desideratum to me to form castings for shafts, cranks, levers, beams, &c., of a sub- stance that should possess the stiffness of cast together with the power of tension and strength of wrought iron. It oc- curred to me that such a discovery would enable the engineer to construct more complete and convenient forms (particularly in the machinery belonging to steam-boats and locomotive engines,) than he is at present able to obtain from the cum- brous forging, turning, and fitting of malleable iron. Such an union of strength I naturally sought for in a mixture of iron and copper ; and knowing that the copper ores of this country are principally sulphurets of iron and copper, I commenced my experiments by attempting the joint reduction of the iron and copper. After many failures I so far succeeded as to effect a perfect reduction into malleable matter of the whole contents of any given sulphuret. But upon examining the results, it was found that a very great uncertainty prevailed as to their strength and quality ; and I soon ascertained that I had only succeeded in obtaining a perfect separation from the ore, of the united products of iron and copper. These masses of alloy were arranged and classified as follows : 1st. Ingots of a coppery coloured surface, covered with aii exterior blackish shale in cooling resembling iron ; breaking with a pale uniform homogeneous fracture, and producing an action more or less on the magnetic needle. 2ndly. Ingots with a gray coppery surface, covered also with an exterior blackish shale in cooling resembling iron, the under surface of a deep red coppery colour. Fracture Mr. D. Mushet 07i the Alloys of Iron and Copper. 83. specular, and beginning to exhibit distinct grains of copper' apart from the iron, as if this metal had been saturated with copper. Small hard and bright iron points appeared under the file. These ingots were obedient to the magnet. 3rdly. Ingots with an iron-coloured surface, and coppery tints displayed under a black thin shale. Hard, and filing to a coppery colour, mixed with bright spots. Fracture specular, exhibiting a mixture of iron and copper, in which the former appeared to prevail. Powerfully acted on by the magnet. The lower surface cellular and crystallized, resembling pro- ducts of fused steel. Though I have divided these products into three classes only, yet I obtained many intermediate results, the iron present in which I estimated at from 5 to 70 per cent, of the weight of the copper. Beyond 5 or 7 per cent, of iron, no chemical union took place ; and as the quantity of iron revived, was in proportion to the charcoal added, so in the same proportion did the separation of the two metals from each other take place. From this it was inferred that malleable iron [i,e, iron contain- ing the least possible quantity of charcoal,) would unite and form a proper alloy with copper, but that steel or cast iron would not do so. To try the validity of this reasoning, a new series of experiments was instituted, having for their object the direct union of a portion of copper with iron in the various states of cast iron, steel, and malleable iron, the general re- sults of which I will state as briefly as possible, without go- ing into a detail of the various experiments. Pure malleable iron may be united with copper in any pro- portion, until it equals, or even exceeds, the weight of the cop- per ; the intensity of the copper colour increases, till the quan- tities are equal ; and the fracture then becomes paler, in propor- tion as the quantity of iron exceeds that of the copper. With 50 per cent, of iron the alloy possesses great strength : its hard- ness increases with the quantity of iron, but its strength after- wards decreases, and in cutting, it opens before the chisel. The loss of strength in proportion as iron is added, arises, I imagine, from the fibre of the copper being injured by the very high temperature required to fuse the increased quantity of malleable iron. The fracture of the ingots thus obtained is always specular, with a glance arrangement, which betokens a tendency to brittleness. If steel is fused with copper in the proportion of ^^^th of the latter to ^gths of the former, an ingot resembling, and crystal- lized like cast steel, will be obtained, but useless for forge purposes, and incapable of receiving an edge. Not the slightest symptom of coj)per, either on the surface or in the fracture, M2 84- Mr. D. Mushet on the Alloys of Iron and Copper, can be perceived, but a very considerable increase of hardness may be observed. When copper is fused with y^^h of its weight of bar steel, an ingot is obtained which outwardly resembles the former, with the radiated linear crystallization less distinct. But the fracture, which is hard and brittle, shows, by minute points of copper, the commencement of an indisposition or inability to further union, or alloy, between the two metals. Again, when ^th the weight of copper is added of steel, an ingot is obtained which exhibits, when filed, a partially cop- pery appearance, of a deep red on the lower, and steel bright on the upper surface. The fracture displays a regular grain, which indicates an intimate mixture of copper and iron, ap- parently of greater strength than in the two former alloys. When 3^rd of copper is added to the steel, the former seems to separate, and seeks in considerable quantities, in a soft and malleable state, the lowest part of the crucible. The fracture exhibits the copper in streaks and knots, indicating a decided want of union*. White cast iron, which resembles steel in the quantity of carbon which it contains, affords nearly the same result when fused with similar portions of copper ; the alloy, however, possesses less strength, and a greater tendency to disunion when the proportion of copper is increased beyond g'oth. The union of copper with gray cast iron, if at all practica- ble, must take place in very minute quantities ; for in fusing 5 per cent, of copper along with No. 1, or smooth-faced pig iron, specks of deep red coloured copper were found upon the lower surface of the ingot, and similar traces were dis- cernible in the fracture. With y'^yth the copper became of a deep red colour, separated in leaves, and attached itself to the outside of the cast iron ; and when copper to the extent of ]-th was tried, a solid button of copper was found beneath the cast iron in the bottom of the crucible. From all I have learnt on this subject, I conclude that cop- per unites with iron in proportion as the latter is free from carbon; hence it would appear impossible to produce a mixed metal, or alloy of copper and iron, by smelting in a blast fur- nace, in contact with carbonaceous matter, an ore containing both these metals. It is true that we have ores which, when * Steel, both English and Indian (or wootz), was alloyed with copper, in the proportion of two per cent, of the latter, by Messrs. Stodart and Fara- day, in their experiments on the Alloys of Steel; but of the value of this alloy, they observe, " we have doubts." They did not attempt to produce it in the large way. See Quart. Journ. of Science, vol. ix. p. 325, 329 ; and Phil. Mag. vol. Ivi. pp. 31, 54; vol. Ix. p. 3/1. — Edit. Mr. A. Trevelyan on the Vibration of Heated Metals. S5 properly smelted, would afford at the first fusion crude steel, which contains a minimum dose of carbon, and to which might be added as much copper as would chemically unite with it, probably from .5 to 7 per cent. But this quantity, I am afraid, would be too small to form an alloy possessed of the strength and power of resistance necessary to made cast- ings for the purposes already mentioned. Though 1 have clearly established by numerous experi- ments the practicability of a perfect union of malleable iron with copper, in every reasonable proportion, yet as this alloy can only be made in a close crucible, it is obviously impossible to employ it for castings of a considerable weight or size. I do not, however, despair of overcoming this difficulty, and of gaining the object I have long had in view by a different system of alloy, in which copper must necessarily form an essent ialingredient. — I am, Sir, your very obedient servant, Coleford, Gloucestershire, Dec. 13, 1834. David Mushet. XII. Further Notice of the Vibration of Heated Metals ; nsoith the Descriptio7i of a new and convenient Apparatus for ex- perimenting with. By Arthur Trevelyan, Esq,*' CINCE my communication on the above subject, published ^ in your Journal of November 1833, 1 have made numerous experiments ; but the only result I have obtained worthy of notice, is that of vibration accompanied with sound when a heated bar of copper or brass, at a temperature of 208° and 212^ Fahrenheit, was placed on a ring of bismuth, having failed in producing it in my previous experiments. With a brass or copper bar placed on a fusible alloy, composed of 5 parts of lead + 3 tin +8 bismuth, vibration commenced at a temperature of 203° Fahrenheit. On a ring of fusible alloy containing the same ingredients and in the same quantities as the former, with the addition of one and a half part of mer- cury, no effect was observable. The accompanying are figures of a convenient apparatus for experimenting with different metals on a small scale. Fig. 1. A gun-metal bar having a groove C, with under-cut edges to receive the wedge ol any metal A, held fast with a pinching-screw B. Fig. 2. A gun-metal ring with wedge of any metal inserted in a groove at D. Fig. 3. Stand, with two uprights and pinching-screw. The * Communicated by the Author, whose former paper will be found in Lond. and Edinb. Phil. Maj^., vol. iii. p. 321. Prof. Forbcs's paper on the same subject will be found in vol. iv. p. 15. 86 Mr. W.G. Horner on the Signs of the Trigonovietncal Lines, ring being placed, the pressure of the screw E, forces it against the two uprights, which tightens it, and by that means fixes the wedge D in figure 2. Fig. 4. Ring and stand complete for experimenting with. Fig. 3. Fig. 4. XIII. On the Signs of the Trigonometrical Lines, By W. G. Horner, Esq,^ 1. "D EGARDED as a demonstration of the algebraic af- ■^^ fections of the trigonometrical lines, the following state- ment (it is hoped) will be found to combine graphical distinct- ness with mathematical evidence. But its chief presumed re- commendation is its completeness. In every treatise that has fallen in my way, the affections of the chords have either been overlooked, or imperfectly, not to say erroneously, discussed. To remedy this fault, the entire system of chords is intro- duced into the annexed diagrams, and the chord is made a principal element in the investigation. 2, The lines C A, AT, (fig. 1.) being at right angles to each other, about the points C and A let two indefinite right lines C P, A P, revolve continuously in the direction ^''"^ . At the outset let the former coincide with C A, and the latter with A T ; and let the latter revolve with half the angular ve- locity of the former. Then [a] when C P next coincides with C A, A P will coincide with T A produced in the direction averse from T ; for this is only saying that the former will ♦ Communicated by the Author. Mr. W. G. Horner on the Signs of the Trigonometrical Lines. 87 Fig. 1. traverse four right angles while the latter traverses two. Also [/3] the point P of the intersection of the revolving lines will describe a circle. For, drop P I perpendicular to A T or its continuation. In either case the z. A C P = 2 I A P ; for it is manifestly indifferent whether these angles are estimated yrcwj the simultaneous outset, or to the simultaneous arrival (a). In fig. 1. In fig. 2. A I = sin ai = cos A T = tan at = cot C T = sec ' and ' Ct = cosec I P = versin / P = covers A P = chd fl P= 1st co-chd B P = sec-chd bP = 2nd co-chd 68 Mr. W. G. Horner on the Signs of the Trigonometrical Lines, Now (Euc, i. 32.), 90° + IAP= ACP + APC=2IAP + A P C .-. 90° -I A P = A P C. But (Euc, i. 29), 90° -I A P = C A P ; wherefore A P C = C A P. Consequently C P = C A constantly; which is the defining property of the circle. Q. e. d. 3. This demonstration obviously applies to angles in every quadrant. And if a is substituted for A, at a quadrant's distance from it (fig. 2.), and i, t, for I, T, the same applies verbatim to the complementary arcs or angles also. Now, T, or /, being placed at the concurrence of C P and A T, or a t and B P being moreover supposed to revolve in the same di- rection /^^ about the point B, or 6, diametrically opposite to A, or «, it is manifest that we have 1^ of ACP. 4. Now, in the first quadrant, to the conditions of which all other quadrants are supposed to conform, the lines A T, A P, C P, B P, are terminated at A, C, B, and extensible only in the directions T and P. If that which is affirmed re- specting any of these lines requires, in any specified quadrant, to be accommodated to the continuation of such line in the opposite direction, the variation will be indicated by a nega- tive sign, as is well known. In my diagrams, the original and accidental or positive and negative lines are distinguished, the former by being drawn with a full stroke, and the latter by being dotted. And to render the whole as completely eluci- datory as possible, I have annexed, rather than suffixed, to each P, I, and T, the number of the quadrant to which it ap- pertains, following in this respect the convenient notation of Mr. Hind. A dotted arrow is also introduced, to show the negative character of such arcs or angles as imply a revolu- tion contrary to the direction originally assumed. If these minutiae answer the purpose intended, of making these diagrams an intelligible substitute for dry tables of + and — , I am sure those who have no need of either will have the good nature to excuse them, for the sake of those who will find them useful. 5. From the diagrams, then, it is apparent that the varia- tions of affection of all the lines, except the chords, are com- pleted within the course of four quadrants, and that they ac- Mr. W.G. Horner an the Signs of the Trigonometrical Lines, 89 cord witli the statements given in every treatise. But it is also apparent from [a J, that the line A P and its continuation back- 'wards from A, complete not their revolution in less than eight quadrants. The affections, in short, of the system of chords are seen to be as under: In quadrant ... chord sec-chd 1st co-chd ... 2nd ... 1 2 3 4 5 6 7 8 + + + + — — — — 4- + — ~ — — + + + — — — — + + + + + + — — """ — + &c. 6. The same results may be obtained from the analytical statements, chd A = 2 sin ^ A, sec-chd A = 2 cos | A, co- chd A = 2 sin J f— + A], on exchanging A for % T A, 2 -TT + A, 3 TT + A, 4 TT T A. It would therefore be better, perhaps, to adhere to this mode of stating the value of the chord, as Woodhouse does in the passing notice he gives it, than by resting on the irrational form to leave the sign uncer- tain. The plan of Mr. Hind's first chapter, it is true, re- stricted him in this respect ; but his unguarded assertion, that '' the chord is positive in every quadrant," has a direct ten- dency to mislead, and should be revised. The versed sine alone is always positive. In conclusion, it may be remarked, that whereas for every other line or function {/) the formula of reduction to the tables or diagrams is y (2 W7r+ A) =y(±A), for the chords itis,chd(2w7r + A) = (-l)"-^chd(±A)= + (-l)"chdA. Mnemonic Hint, Setting aside the versed sine and chord, whose aifection, as well as value, is clearly expressed by 1 — cos A and 2 sin ^ A, the affection of the principal lines is indicated by the order in which it is most natural and usual to name them, viz. Sine, Tangent, Secant. For, in the 1st quadrant all being + ; in the 2nd all are — , except the Sink and its reciprocal the cosecant. In the 3rd. all are — , except the Tangent and its reciprocal the cotangent. In the 4th all are — , except the Secant and its reciprocal the cosine. Note (relative to a formula in Lond. and Edinb. Phil. Mag., vol. v. p. 191.) — Having still a space left, I take the oppor- tunity of remarking, that the method of elimination by the common measure, although tempting by its facility and ele- mentary nature, is too defective to deserve recommendatioq. Tliird Series, Vol. 6. No. 32. Feb, 1835. N 90 The Rev. P. Keith o?i the Structure of Animals, By adhering to the method by combinations or symmetrical functions, the complete formula (.r^ — SI -f-j9) {(3« — s) x'^ — ^{as — 'p)x-\-a'p} = 0, would have resulted in place of (C), which contains only the latter factor; and the evidence adduced would have been somewhat more clear. XIV. Of the Sti-ucture of Animals. 5j/ Me .R^t;. Patrick Keith, F.L.S.y &c. [Concluded from p. 16.] Class2, TF we look at an individual of the class of Birds, we -*- shall find that it exhibits the same general type of structure with that of the Mammalia, consisting ofhead, neck, body, limbs. The head, as in the foregoing class, is the seat of the organs of sense, furnished with and terminating in a bill, by which the individual picks up and breaks its food. The form of the bill differs much in different species, and serves as a mark to discriminate tribes or families. The head, neck, and body are covered with feathers, which are often adorned with the brightest and most brilliant colours. The neck assumes the circular form, and often displays peculiar beauty, as well as peculiar flexibility, as any one who has seen a swan in the act of swimming will, with Milton, readily admit : " The swan, with arched neck Between her white wings mantling, proudly rows Her state with oary feet." — Paradise Lost, b. vii. The greatest bulk of the body is around the breast, tapering towards the tail, which is composed of feathers of a peculiar form, — magnificently illustrated in the tail of the peacock. The fore limbs assume the position and fan-like form of wings, to fit the individual for its flight in air; and are often composed of, or rather covered with, a plumage that is most splendidly brilliant. The hinder limbs always terminate in feet, divided into toes tipped with claws, some genera having the toes sepa- rate, as the pheasant and partridge ; and some having them united with a membrane, as the swan and goose. The former are land birds ; the latter are water, or web-footed birds. Class 3. In this class, the class of Fishes, the vestiges of the general type, though much metamorphosed, can still be readily traced. The head is very distinctly visible, furnished with its projecting mouth and devouring jaws. The eyes are sufficiently conspicuous ; but the other organs of sense have no very visible development of external parts. The head is The Rev. P. Keith on the Structure of Animals. 91 joined to the body without the intervention of any distinct portion that can properly be called a neck; but about the junction of the head and body we find on each side an ex- ternal organ peculiar to fishes, namely, the gills, — their organ of respiration. The body, which is covered with scales, is rounded, and tapering from head to tail, as in the eel ; or a little flattened in a vertical direction, as in the trout and salmon ; or much flattened in a horizontal direction, as in the sole and flounder, and in all flat fish : the limbs, whether an- terior or posterior, are metamorphosed into fins to fit them for the act of swimming in water. By the lateral flexion and ex- tension of the caudal fins the body is impelled forwards with great force, ascending or descending chiefly by means of the compression or dilatation of the swim-bladder, an organ with which most fishes are furnished ; but such as are destitute of it, like soles and flounders, must be content to swim very near the bottom. Some fishes have the capacity of leaping out of the water ; and one, Trigla volitans^ — the flying fish, — has the very singular property of being able to take a short flight even in air. Class 4. In this class, the class of Reptiles, the general type is in most cases very obvious, exhibiting a head, with a mouth and eyes distinct; a visible neck; a body naked, as in the frog ; or covered with shell, as in the tortoise; without a tail, as in the toad ; or furnished with a tail, as in the lizard. The limbs, anterior and posterior, are so excessively short as scarcely to be able to raise the body above the level of the ground ; and in the order Serpentes even limbs are wanting. Many of the Reptilia are amphibious, and can live either on land or in water; and most of them during the winter months sink into a state of torpidity, from which they are aroused only by the returning warmth of the succeeding spring. Division II. The Mollusca. — The next division of animals in the descending scale is that of the Mollusca. They are distri- buted into three classes, — the Cephalopoda^ in which the feet, or organs of locomotion, are inserted in the head ; the Gaste- ropoda, in which the foot, or organ of locomotion, is the ab- domen ; and the Acephala, in which no distinct head is visible. In each class there is an order that is inclosed in a shell, or testaceous covering; and an order that is naked. Class 1. In the first class we find the Sepia, or cuttle-fish. They are of the order of naked Mollusca, and in their general aspect are but a shapeless mass. The head, however, is di- stinctly visible, furnished with eyes and organs of hearing, as well as with presumed organs of smell, from the fact of their N 2 92 The Rev. P. Keith on the Structure of Animals. aversion to strong-scented plants *. Around the head there are fixed a number of arms, which are the organs of locomo- tion and of prehension. In Sepia officinalis they are ten in number, two of them being longer than the rest. The arms are furnished with suckers, in the shape of excavated tubercles, by which the individual can fasten itself firmly to external sub- stances, and thus stand, as it were, upon its head. The Sepice have the peculiar property of ejecting at pleasure from the ab- domen an inky-coloured fluid, that darkens the water in their vicinity, and renders them for a time invisible to their pur- suers. They are not uncommon on the coast of England. Class 2. In the second class we have the slug, that infests our gardens and corn-fields during the spring and summer, devouring the radicle, or the cotyledon, or the tender blade of the young plant, and blasting the golden hopes of the too san- guine cultivator. The largest of the tribe, when extended, may be about the size of a finger. The head is furnished with a mouth, by which the individual gathers its food ; and with a pair of horns, or feelers, terminating each in a black point, which is regarded as an organ of vision. It slides along upon its abdominal surface by a sort of vermicular movement, leaving a slime behind it; and it has the capacity of contract- ing its extended body into a very small compass, if affected by fear or hastily interrupted in its peregrinations. Class 3. In the third class we have the oyster in its shell, the delight of the gourmand, or connoisseur in sauces, and so well known to every lover of good things as scarcely to stand in need of any description. It belongs to the order of acepha- lous bivalves, having its abode in the ocean, but choosing as its favourite habitat the mouths of rivers or of estuaries. It sheds its spawn in the month of May on rocks and stones or other substances at the bottom of the water, to which the young brood clings till detached by the industry of the dredger, to be transported to beds calculated to forward their growth and give additional delicacy to their flavour. The oyster seems to be destitute of all organs of locomotion, and yet it is capable of changing its place. By opening its shell to a certain width it takes in a portion of water, which it has the power of squirt- ing out again with considerable force, and in any direction, and of thus propelling itself to any point in a direction con- trary to that of the force exerted. Division III. The Articulata. — The third division of animals in the descending scale is the Articulata, which have * Carus, Compar. Anat., i. 74, by Gore. The Rev. P. Keith on the Structure of Animals. 93 the body externally divided into a succession of rings, or arti- culations. They are distributed into the three following classes : The Vermes, or worms, in which the body is without any external organs of locomotion ; the Crustacea, in which the body is covered with a shell ; and the Insecta, or insects, in which the body is divided by deep indentations into four principal parts,— the head, the corselet, the chest, the ab-* domen. Class 1. The first class is exemplified in Lumhricus teV" restris, — the earth-worm. At its mature size it may be about a span in length, with the circumference of a goose-quill. The head is indistinct, but the mouth is not so. The body is soft and gelatinous, and articulated on the external surface, with a sense of touch chiefly about the two extremities ; but without any external and distinct organ, whether of hearing or of sight, and without feet, but covered with projecting bristles, or tufts of hair, which in some measure supply their place. Class 2. The second class is exemplified in the crab and lobster, shell-fish that are well known. They inhabit rocky shores, or shallows of the ocean, and feed upon sea-weed and all manner of garbage. The head is furnished with feelers and with moveable eyes. The legs are eight or ten in number, with five articulations, the first pair ending in claws or nip- pers, and, like the body, covered with shell. If they lose a limb by accident, they have the power of reproducing it. Lobsters have a long and articulate tail, covered with a horny coat, composed of several portions that move one upon another. They shed their shells annually, and screen themselves for a few days under the shelter of stones and rocks till the new shell is sufficiently indurated to defend them from the ordinary accidents to which the element they inhabit exposes them. At last they are caught by the art of the fisherman, and forwarded to the tables of the lovers of luxuries, where they are much esteemed for the delicate morsel, or for the rich and piquant sauce which their edible portion affords. The natural colour of the lobster is black ; but when boiled it changes to red, — a circumstance that the author of Hudibras has turned to good account in the getting up of one of his ludicrous similes : •* The sun had long since, in the lap Of Thetis, taken out his nap ; And, like a lobster boiled, the morn From black to red began to turn." Hudibras, part ii. cant. 2. Class 3. The third class is exemplified in the silk-worm, PhalccnaMori. If in its native country of China or of India, it lays its eggs in summer on the boughs of the mulberry-tree. 94 The Rev. P. Keith on the Structure of Animals, They are small yellow globules, about the size of a millet- seed, and a single female will lay several hundreds of them; but where such trees are not to be found, as in the case of the transporting of the species into other climates, the female will lay her eggs on whatever substance she may happen to have access to. To this substance they remain agglutinated during the winter that succeeds, and begin to be quickened by the re« turn of spring, till in the month of May they are evolved into life; that is, as kept in the cabinets of the curious of this coun- try. The protruded insect is now a caterpillar of a very dimi- nutive size, consisting of a head, a mouth, and a body com- posed of seven rings, and furnished with the same number of feet on each side. If well fed with mulberry leaves it will grow very rapidly, and in the course of five or six weeks will have attained to its full size ; that is, to a length of nearly two inches, with a diameter equal to that of a goose-quill. It now sickens and refuses food, and sheds its skin ; revives, and feeds, and sickens, and sheds its skin again, and again ; and on its third or fourth revival selects, after a day or two of indecision, a suit- able spot for future operation, and begins to weave its cocoon, which it completes in about a week. Imprisoned in its cocoon, it puts off the caterpillar form entirely, and is metamorphosed into a chrysalis or pupa, in which state and prison, after a so- journ of about another week, it eats or forces its passage out, and is ultimately transformed into an imago, or moth, not adorned with brilliant colours, but exhibiting in its form and structure much of beauty and of elegance,, and of an indescri- bable something that seems to indicate its Oriental origin. In this state it lives three or four days, occupied in the process of propagating the species, and of laying its eggs ; and this done, it dies. Division IV. The Radiata. — The fourth and last division in the descending animal scale is that oHheRadiata, including the zoophytes of the earlier botanists, — whose leading character is that they have their parts arranged in a radiant or divergent di- rection around a common centre. The division forms a class, consisting of the five following orders : — 1st, Echinodermata : the body inclosed in a crustaceous covering, beset with spines. 2ndly, Medusce, or sea-nettles : the body soft and gelatinous, stinging the hand that touches them, and furnished with ten- tacula. 3rdly, Corals and corallines: the body covered with a shell-like or stony crust, or surrounding an insensible stalk, — stirps radicata, attached, — the mouth furnished with tentacula. 4thly, Polypi: the body a bag of jelly, pedicled or without a pe- dicle, but unattached, — stirps libera, corpus liberum,^^the mouth furnished with tentacula. 5th]y, Infusoria: the body a gela- The Rev. P. Keith on the Structwe of Animals. 96 tinous globule, with no external organ or apparent orifice.* Professor Grant f has shown that the orders arising out of this division may be increased with advantage to the science ; but those we have adopted are sufficient for general purposes. 1st. The first order is exemplified in the ^euua Asterias^ or sea-star, with its five radiating lobes ; or in the genus Echinus^ or sea-urchin, with its thousand spines. These genera are common on the shores of England; and when the inclosed animal dies, the empty covering is often to be met with lying on the sea-beach, as it may have been accidentally thrown up and left by the flux and reflux of the tide. 2d]y. The second order is exemplified in the genus Actinia^ — animal flower, or sea anemone. It is found in great abun- dance on the coasts of the West India islands. It is club* shaped, fig-shaped, or cylindrical, and fixed by the smaller or lower end to rocks, or to stones lying in the sand. To this mode of attachment the Actinia sociata is an exception, the foot being fixed, not immediately to the rock, but to a firm and fleshy tube, that creeps along horizontally, and sticks fast to the surface, resembling in some degree the souche souterrain of the common brakes. At the upper extremity there is a single opening, which is the mouth, leading directly to the stomach, which is a blind sac. The tentacula, when expanded, are said to exhibit an appearance similar to that of the petals of the anemone, whence the name. They are tinged with a variety of bright and brilliant colours, and are the instruments which the animal employs in the seizing of its prey. The Actiniae are very voracious. They will swallow a muscle or an oyster entire ; and after having extracted the internal nutri- ment by the digestive power of the stomach, they will again eject the shell by the same aperture at which it entered. They are also remarkable for their capability of being multiplied by division to any extent. Cut up a single individual into a thou- sand pieces, and each piece will become a complete Actinia^ furnished with all the peculiarities of its species {. But an example more within the reach of the zoological student is that of the Medmce^ common on the shores of the British isles; but better known, perhaps, by the vulgar ap- pellation of sea-blubber. They are of a globular form, of a soft and pulpy consistence, and of a shining pale blue colour, dashed with a tinge of violet. You may see them approaching * [This statement agrees with the views respecting the Infusoria which, until lately, were entertained by naturalists; but the recent discoveries of Ehrenberg (and it might be added the neglected observations of Gleichen,) have shown that they possess a mouth, many stomachs, and other elements of a complex organization. — Edit.] f Lectures at the London University, Nov. 1833. X Encyclopedia Britannicay " Animal Flower." 96 The Rev. P. Keith on the Structure of Animals, the coast with a flood tide, floating or drifting on the surface of the wave, sometimes singly, and sometimes in multitudes, under the semblance of a large lump of jelly, — in Medusa auritanot less than three or four inches in diameter, — with their tentacula spreading around them. They emit a phosphorescent light in the night, and when voyaging in large shoals illumi- nate the surface of the deep. They sting the hand that touches them, and cause a tingling pain. Srdly. The third order includes corals, corallines, and sponges, in which a sensitive body surrounds an insensible stalk, or is inclosed in an insensible covering, — stony, crus- taceous, or horny ; not constructed by the animal itself, but congenital with it; not phosphatic, but calcareous, — stirps radicata, — attached. The former varieties occur in the Gor^ gonicE, the latter in the TuhijporcB and Celleporcc, 4thly. The fourth order is that of the Polypi^ the body being a mere bag of jelly attached to a stirjps libera^ as in the case of the sea-feather ; or wholly unattached, — corpus liberum, — with arms radiating from the mouth. Some of them you may turn inside out, like the finger of a glove, and the animal shall still live. You may cut them into as many pieces as you please, and each piece will become an entire animal. Hydra viridis is a good example. 5thly. Finally, the fifth order is that of the Infusoria, which consist merely of a small and pulpy globule, capable of a brisk and spontaneous motion, but furnished with no external organ whatever. If a drop of water taken from a ditch or pond in which vegetable substances are becoming putrid, or if a drop of rain water that has stood exposed to the weather for a few^ days, is put upon the stage of a good microscope, and the eye applied to it, you may see hundreds of them frolicking in that single drop, like fishes in the ocean. Thus life assumes a great variety of different aspects, ac- cording to the tribe or family in which we contemplate its phasnomena ; and thus a scale of degrees, from man down- wards, is evident even from the contemplation of the external structure. In man you have the several parts of the body the most distinctly marked, — the head, the neck, the trunk, the limbs; and the organs of sense the most fully developed, — the eye, the ear, the nose, the palate, the touch ; with the peculiar conformation of the foot and of the hand, — the former serving as a basis to support the body in the erect posture, and the lat- ter as an instrument adapted to the thousand different purposes for which man may have occasion to employ it, — whether in the fine arts, as in music, drawing, painting, sculpture ; or in the domestic arts, as in the fabrication of clothing or the construc- tion of machinery ; or as in the operations of agriculture ; or Mr. Everitt ow the Preparation of Hydrocyanic Acid. 97 of war, whether military or naval; or as in the manipulations of chemistry or of anatomy; or, finally, as in almost every art or exercise that man has occasion to perform. Apes, though furnished with four hands, have no hand equal to that of man. If they had the hand, they have not the skill to direct it; and if they had the skill to direct it, they have not the hand. With quadrupeds the case is still worse. From the size and struc- ture of their fabric, many of them have greater strength or greater swiftness than man ; but they have no hand. A hoof is but a very inadequate substitute for it; and even with all the advantages of mind, man would be nothing without the master instrument of the hand. Birds, fishes, and reptiles are, by their organization, removed still further from man than even quadrupeds; while the other divisions of the animal kingdom, — the Mollusca, the Articulata, and the Radiata, — are removed even further still. For to whichsoever of them we direct our regard, we find in their external structure nothing that ap- proaches to the type of man, nothinir that is fit to be compared to the fabric of the human body, and nothing that equals the capabilities of its several organs, whether for the purposes of sense, of prehension, or of progression ; but rather an increas- ing dissimilitude of structure, in proportion as you approxi- mate the bottom of the scale, till at last you reach the minute and microscopic, but brisk and agile animalcule, that wheels and frolics in its drop of fluid, and yet exhibits no visible indica- tion of being furnished with any external organ or instrument of locomotion whatsoever. Thus man stands, without a rival, at the head of the animal creation, — the image of his Maker, " the noblest work of God" ! P. Keith. Charing, Kent, Oct. 1, 1834. XV. On tlie Reaction "^hich takes place nsohen Ferrocyanuret of Potassium is distilled with dilute Sulphuric Acid ; with some Facts relative to Hydrocyanic Acid and its preparation of uniform strength. By Thomas Everitt, Esq., Professor of Chemistry to the Medico- Botanical Society, Sfc* (1.) AS the decomposition of the ferrocyanuret of potassium -^ by means of sulphuric acid is likely to become the only method by which hydrocyanic acid will be prepared for chemical and medical purposes, on account of the cheap rate at which this salt is now to be had chemically pure ; and as in all operations of this sort the more exactly we adhere to the proportions indicated by an accurate knowledge of the na- • Communicated by the Author. Fhird Series. Vol. 6. No. 32. Feb, 1 835. O 98 Mr. Everitt ofi the Beaction of Ferrocyanuret of Potassium tiire of the interchange which takes place during the process, the more uniform and satisfactory are the results, and the more do we economise our time, I have been induced to examine very narrowly the above reaction. (2.) Assuming the composition of the crystallized yellow ferrocyanuret of potassium to be 2 K Cy + Fe Cy + 3 Aq, I find that on boiling it with sulphuric acid in a close vessel, fths of the potassium remain in solution as bisulphate of po- tassa, its cyanogen going off as hydrocyanic acid: the re- maining :Jth combines as cyanuret of potassium with all the cyanuret of iron to form a yellow insoluble salt : thus, 2 proportions of the crystals. '3 Cy H. which escape as gas. r4K 14 Cy (2¥e \2Cy 6Aq with 6S I 3 (K-f- 2 S) bisulphate of potassa in so- lution, j 3 Aq— free. Lk Cy+2 Fe Cy, which fall as yellow salt. Or in numbers : 2 proportions of salt. 39- 15 X 4 potassium 28 X 2 iron 26-39 X 6 cyanogen 9x6 water Real sulphuric acid. 40 X 6 Results. 3 (26-39 + 1) hydrocyanic acid. 3 (39-15 + 8)+ 6(40)bisulph.ofpot". 9x3 free water. (39-15 + 26-39) + 2 (28 + 2639) yellow salt. Hence 2 proportions of salt 212*47 X 2 = 6 proportions of sulphuric acid 40* X 6 = yield 3 proportions of hydrocyanic acid 27*39 X 3 = 3 proportions of bisulph. of potassa 127*15 X 3 = 3 proportions of water 9*00 X 3 = 1 proportion of yellow salt K Cy 65*54 + 2 Fe \ __ Cy 108-78 / - 424*94 240*00 82-17 381*45 27*00 174*32 664*94 664«94 (3.) This was proved as follows : {a.) 212*5 grains of the crystals of ferrocyanuret of potas- sium were dissolved in 2 fluid oz. of water, to which were added 600 grains of dilute sulphuric acid of specific gravity 1*179, containing 20 per cent, of real acid, and therefore amounting in all to 120 grains real acid ; the mixture was kept boiling in a vessel partially closed to prevent the free ingress of air, till the odour of hydrocyanic acid ceased to be given off: and dilute Stdphuric Acid, 99 the yellow salt collected, washed, and dried at 220°, weighed in Experiment No. 1, 88*1 grs. ; No. 2, 88*0 grs. ; No. 3, 87*1 grs. The calculated number is 87*16. The salt is very liable to assume a delicate green tint unless the air be very carefully excluded from the vessel, and hence its true colour cannot be seen, unless the flask, previously to adding the acid, be filled with carbonic acid gas ; the green tint always goes off on dry- ing it at about ^00° F. {b.) The colourless solution which passed the filter, leaving the yellow salt on it, and which contained the bisulphate of potassa, required, to render it neutral, of crystallized bicarbo- nate of potassa, (I used this as being the most definite and manageable salt we have,) in Experiment No. 1, 152*1 ; No. 2, 151*0; No. 3, 150*6 grs. The calculated quantity isl4(K + 2C+l Aq) 150*58 grs., showing that 3 proportions of sulphuric acid had taken up only 1^ potassa. After neutralizing the liquid with bicarbonate of potassa, it was in two cases evaporated to dryness, and the neu- tral sulphate weighed, which confirmed in both cases the above results, and proved that no other salt was in the solution : also in one case, the sulphuric acid was precipitated by nitrate of barytes, which proved that all the sulphuric acid was in the solution. {c.) The hydrocyanic acid given off was estimated by taking 106*3 grs. of the ferrocyanuret of potassium in 2 fluid ounces of water, + (300 grains of dilute sulphuric acid of specific gravity 1*179) = 60 grains of real acid, and by means of a tube and cork conducting the vapour into a large receiver, containing a dilute solution of nitrate of silver: the cyanide collected and weighed, gave in Exp. No. 1, 103 grs. ; No. 2, 102*3 grs.; No. 3, 101*4 gr. The calculated number is 100*8 grains. Most likely in ex- periment No. 1. the matter was not perfectly dried; but the three come sufficiently near to leave no doubt of the theoretical quantity. (4.) Hence I conceive that the exposition of the reaction given at the commencement of this paper is fully proved. I am well aware that in the 46th volume of the Annales de Chimie et de Physique, p. 77, M. Gay Lussac states that a white salt is produced during this reaction. I have operated with distilled sulphuric acid, conducted the process in a nar- row-necked flask, into which a stream of carbonic acid passed during the whole of the boiling, and it was always of a light lemon colour : in ordinary cases, when this extreme care was 0 2 100 Mr. Everitt on preparitig Hydrocyanic Acid from not taken, it was greenish. Perhaps M. Gay Lussac poured strong sulphuric acid on the powdered crystals, when a very complicated change takes place. (See Thomson, 7th edition, vol. ii. p. 251.) M. Gay Lussac also states, that after making a few experiments on the new salt, the results appear {'' sem- blent" showing that he trusted more to the pen than the ba- lance,) to lead to the consequence that it is a compound of 9 cyanogen, 7 iron, and 2 potassium ; so that supposing we have enough of the original ferrocyanuret of potassium to yield 14? proportions of potassium, 7 of iron, and 21 of cyanogen, then by boiling with sulphuric acid, 7 proportions of iron, + 2 potas- sium + 9 cyanogen fall, 12 of cyanogen go off* as hydrocyanic acid, and 12 of potassium are dissolved by the sulphuric acid. Now, I prove by {b.) that the relation of the potassium dis- solved by the sulphuric acid to that precipitated is as 3 : 1, and not as 6: 1; by (c.) that the relation of the cyanogen dis- engaged as hydrocyanic acid is to that in the precipitate as 1:1, and not as 12 : 9. And the quantity of yellow salt pro- duced in («.) serves to confirm both the above results. The theory of the subsequent conversion of the salt into Prussian blue by moistening it with dilute sulphuric acid and exposing it to air is consequently unknown. I have not yet examined the precise change which takes place with sufficient care to give an opinion: that potassa is dissolved out, and that the action of free oxygen is essential to the change, is certain. (5.) Had I examined Gay Lussac's paper before I began my experiments, his high authority would have made me con- sider any further experiments on this subject as useless; but as I had finished the experiments marked Nos. 1 and 2, before I saw his paper, I was induced to repeat my experiments with redoubled care : hence the series No. 3, and hence their nearer approach to the calculated numbers. I must therefore con- clude that M. Gay Lussac has operated on the salt obtained by the action of concentrated sulphuric acid on the crystals. The change in that case, according to Thomson, is so com- plicated that sulphurous gas, ammonia, carbonic oxide, azote, are given off'. I doubt if any definite conclusions can be drawn from it. (6.) The best proportions, therefore, of the ferrocyanuret of potassium and sulphuric acid to be used when we want hy- drocyanic acid are as follows. To every 212*47 grains of the crystals dissolved in about 2 fluid ounces of water, add so much dilute sulphuric acid as shall contain 120 grains of real acid, and by conducting the distillation carefully, 41 grains of hydrocyanic acid pass off", and that I find with the first Jrd of the water: of course water must be put into the receiver and Ferrocyanuret of Potassium and Sulphuric Acid. 101 kept very cold. But no process for procuring a dilute solu- tion of hydrocyanic acid, in which distillation or filtration is had recourse to,will yield an acid of uniform strength, however carefully the process may be conducted, not even, as I have proved, if the receiver be surrounded with ice. Hence the absolute 7iecessity of assaying in all such processes the ultimate product, either by the nitrate of silver or the peroxide of mer- cury method ; the first is to be preferred : we have the great advantage that any error committed in collecting, drying, and weighing, is reduced to ^ in estimating the quantity of real acid, 100 grains of the cyanide of silver corresponding to 20-38 of hydrocyanic acid. (7.) In addition to the very elegant application of the nitrate of silver for detecting the presence of free hydrocyanic acid in its passage as vapour from a dilute solution, or in any plant containing the acid, (thus, masticate a bitter almond, put it in a watch-glass, and cover it with a bit of glass, on the under sur- face of which a drop of dilute nitrate of silver is placed; in a few minutes the cyanide of silver is formed, — an experiment which may serve as a class illustration of the extreme volatility of the substance,) recommended by Mr. Barry in the London and Edinburgh Philosophical Magazine, vol. iv. p. 151. Mr. Barry has also put me in possession of a means as elegant for the testing of the presence of minute quantities of hydrochloric or sulphuric acid in hydrocyanic acid, viz. Put some of the acid on a watch-glass, add two or three drops of liquor am- moniae, put the glass on the sand-bath, and evaporate to per- fect dryness, when all ammonia and hydrocyanic acid pass off, leaving only, if any hydrochloric or sulphuric acid be pre- sent, a little hydrochlorate or sulphate of ammonia behind; a drop or two of distilled water will dissolve these, and by ni- trate of silver added to one half, and nitrate of barytes to the other, the presence or absence of the above acids will be de- termined. If the hydrocyanic acid be quite pure, the watch- glass after evaporation is scarcely soiled, and water dissolves nothing : this method is far preferable to that by means of car- bonate of lime usually recommended. (8.) In a paper which I read to the Medico- Botanical So- ciety, on Tuesday, Dec. 9, 1834, on the methods of assaying medicinal hydrocyanic acid, I stated that I had examined sam- ples of the acid procured from various shops in town, and that the frightful difference of strength had induced me to make the results known, with a view of calling the attention of the medical profession to the evil. Thus, samples from Allen, Hanbury and Co. yielded 5*8 per cent.; from Apothecaries' Hall, at different times, from 2* 1 to 2*6 per cent. ; and from 102 Mr. Everitt on preparing Hydrocyanic Acid several sources I found acid containing only 1*4' per cent. These samples I procured from the several shops personally, and asked for Scheele's strength. They were assayed within 24 hours after they were in my possession, both by the nitrate of silver and the oxide of mercury method, and the results in no cases varied more than y\yth of a grain from each other. Now it is true we have no fixed standard, and therefore it is impossible to say whether Allen and Co.'s is too strong or the others too weak ; but thus much is certain, that if a me- dical man were pushing the exhibition of hydrocyanic acid gradually to a maximum dose, the prescriptions being carried to a shop where the acid had only 1-4 per cent., and then by some accident or other cause taken to where Allen's acid was used, a sudden and I fear a fatal increase would be the result, for more than a triple quantity would be taken. For the pos- sibility of a fatal accident, I need only refer to the case of seven individuals near Paris being killed by a slightly in- creased dose, recorded in all the medical periodicals a few years since. (9.) On the same evening I called the attention of the members of the Medico- Botanical Society to the method for procuring medical hydrocyanic acid recommended by Dr. Thomas Clarke, by cyanide of potassium and tartaric acid; a method which can now be employed by any one, since Mr. Laming has brought into the market a very pure salt. From very numerous trials, I find that the procuring of this salt, the cyanide of potassium perfectly pure, must be expensive; and I have never been able to procure it strictly in this state without using alcohol to crystallize it from : and many che- mists, I find, (see Mr. Barry's paper above alluded to,) object to it, from its being so excessively deliquescent, and hence rather unmanageable, and also to the liability of this highly poisonous salt being mistaken for other white salts on their counters. This latter objection, I must say, is hypercritical : if people will be careless, there is no means of preventing mis- takes, and I conceive the objection of Mr. Barry applies with tenfold force to many arrangements of a druggist's shop, where we often see tincture of opium flanked right and left by other dark tinctures; and who that has manipulated has not caught himself laying hold of, and using one acid, &c., for another when the mind is also at work ? (10.) I have made many trials as to the practicability of applying the cyanide of silver and dilute hydrochloric acid for procuring medical hydrocyanic acid. The cyanide of silver presents many advantages : it is perfectly stal)le, being neither affected by light nor moistuve; its purity can be very easily as- of uniform Strength from Cyanide of Silver, 103 certained, and every five grains of it will yield one grain of acid. It can be procured by conducting the vapour from the process described in section (6.) of this paper, into a pint of water, hold- ing 255 grains of nitrate of silver, washing and drying at 212°. It yields 201*6 grains of white cyanide. 1 should recommend that the bottle containing this salt be accompanied by a small stoppered phial with dilute hydrochloric acid of such strength, that 1 minim will exactly decompose 1 grain of the cyanide: thus, suppose one corked phial having 200 grains of cyanide with one |-oz. stoppered bottle with hydrochloric acid of specific gravity 1*129, this would be enough to make 5 fluid ounces of dilute hydrocyanic acid of the Dublin strength, if the following formula be followed. Into a phial capable of holding rather more than 1 fluid ounce, put 40 grains of the cyanide, add 7 fluid ounces 20 minims of water, and 4-0 mi- nims of the dilute hydrochloric acid; cork closely, shake se- veral times for the first quarter of an hour, set aside to allow the chloride of silver to fall, decant the clear liquid into ano- ther bottle to be preserved for use : every fluid drachm will contain 1 grain of real hydrocyanic acid. The only objection I had a priori to this process was the lia- bility of a little free hydrochloric acid remaining in the solu- tion, since all books echo that the presence of a minute quan- tity of the mineral acids very much hastens the decomposition of this acid ; a statement perfectly opposite to fact, at least as far as concerns hydrochloric acid. I prepared 4 ounces of hydrocyanic acid perfectly pure by distillation off* chalk; to 2 ounces I added 5 drops of hydrochloric acid ; the other two ounces in another phial were left perfectly pure, both inverted and placed in a glass case so as to have diffused light during the day. After three weeks the pure acid had become quite brown, and a considerable quantity of solid deposit had formed ; the other remained quite limpid and colourless, and on actual trial was found to contain |^§ths of the acid which it had at first. Mr. Barry also informed me that his fourteen years' expe- rience led to the same result ; and that, being aware of this, he adds purposely a little hydrochloric acid to all his medi- cinal acid. Perhaps some may object to the price of the pre- paration : a case containing the two bottles with 200 grains of the cyanide would leave one half profit if sold for 5s, ; this brings an ounce of acid to 1 5., and where so small a quantity is used, surely this cannot be a very weighty objection, if a uniform article can be secured. 28, Golden-square, London, Dec. 12, 1834. [ 10* ] XVI. On the Forms of Sulphur et of Nickel and other Substances. By W. H. Miller, M.A., Fellow and Tutor of St, John's College and Professor of Mineralogy in the University of Cambridge,* T F a sphere be described round any point in a crystal as a -■- centre, and if radii be drawn perpendicular to the faces of the crystal, meeting the surface of the sphere in points, which we shall call the poles of the corresponding faces, the supple- ment of die angle between any two faces will be measured by the arc joining their poles; and if any number of faces lie in the same zone, their poles will lie in the same great circle : also, the supplement of the angle between the intersections of any face with each of two other faces will be equal to the angle contained by the great circles drawn from the pole of the former face through the poles of the two latter. Hence, a sphere having the })oles of the faces of a crystal mapped upon its surface in the manner above described, or its projection, will serve to determine the form and relative positions of the faces of a crystal. This method of representing crystalline forms, the invention of which is due to Professor Neumann of Konigsberg, will be used to illustrate the crystallographical notices which follow. The degrees and minutes express the values of the arcs joining the poles of the faces, or the supplements of the angles between the faces themselves. The symbols of the faces are expressed in the notation pro- posed by Mr.Whewell, in a memoir published in the Philo- sophical Transactions for 1825, and of which an account is given in the Encyclopaedia Metropolitana, Art. Crystallo- graphy. The chemical notation and atomic weights are taken from the fifth edition of Dr. Turner's Chemistry. Sulphuret of Nickel. Ni + Su. — The crystals of this mi- neral belong to the rhombohedral system, and usually occur in very slender hexagonal prisms, which, when broken across, exhibit the feces O, Q, R, S, V : one crystal was terminated by dull faces T, forming an acute rhombohedron. In order, if possible, to determine the value of O T, the crystal was fixed to a ruler so that the faces M T were perpendicular to the plane of the ruler, and placed under a compound micro- scope having a fine wire stretched in the focus of the eyepiece. The ruler was then turned round in its own plane till the images of M T seen edgeways coincided successively with the wire, and the position of the ruler at each observation marked by a line drawn along its edgQ on a table; the angle contained * Communicated by the Author. Prof. Miller on the Forms of Sulphur et of Nickel, Sfc, 105 by these lines, or 90° — OT, being measured, the resulting value of O T was between 48° and 49°. In the same man- ner the angle between the axis of the prism and the intersec- tion of T T, was found to be nearly 61°. By a number of observations made with the reflective goniometer, O R was found equal to 20° 50'. Now, 3 tan 20° 50' = tan 48° 47', and 4 tan 48° 47^ = cotan 61° 17'. Hence it appears that the value of O T was measured with sufficient accuracy to be used in finding the symbol of T. O (1, 1, 1), Q(l, 1, 0), R (1, 0, 0), S(2, 2,-1), M (1,1, -2), T(4,4,— 5), V (-1,— 1,4), L (4,1, -5). OM = 90° 0' MM = 60 0 ML = 19 6 OQ r= 10 46 OR r= 20 50 OS = 20 50 OT zr: 48 47 OV sr: 4^3 34 QQ = 18 38 RR = 35 52 RS = 20 30 2'4S2 grains of the mineral weighed 2*012 grains in distilled water at 15° C. In a second experiment 2*431 grains were found to weigh 1*969 grains in water at the same temperature. The resulting specific gravities are 5*280 and 5*262. Sulphate of Oxide of Copper and Ammonia. Cu S + 3 H N S + 7 H. Oblique prismatic. A(1;0;0), C(0;0;1), P(l;l;l), Q(l;-l;l), H (0; 1 ; 1), M(1;1;0), T(2;0;l). AT = 41°12i' <^ P — a^f^oQi-lf TC = 64 54 CA =73 534 MM =108 56 AM = 35 52 PP =139 37 HH =127 39J QQ =140 16^ AQ = 48 13^ CH = 26 lOi AH = 75 35 When yellow light is refracted through the faces T C, the Third Sei'ies, Vol. 6. No. 32. Feb. 1835. P CP = 45°31i' AP = 69 lOi CM = 76 57 CQ = 34 35^ PT = 54 39 MT = 52 15 AYP = 66 52 AYQ = 44 56 106 Prof. Miller on the Forms of Sulphur et o/NicJcel, S^c, minimum tleviation of a ray polarized in the plane T C A is about 42°. Asparagine. — Prismatic. The number of crystals at my disposal was too small to ensure great accuracy in the deter- mination of the angles. B(0;1;0), P(l;l;l), M(1;1;0), N(2;l;0), K(1;0;1). B M = 39°47' B N = 59 1 K K = 50 42 M P = 53 29 BP = 62 47 KP = 27 13 N P = 55 49 K N = 68 28 XP = 67 37 The ratio of the velocity of light in air to its velocity within tlie crystal is 1*623, for a ray perpendicular to B B, polarized in a plane perpendicular to B B ; 1 '600, for a ray perpendicular to Z Z, polarized in a plane perpendicular to Z Z ; 1 '583, for a ray perpendicular to X X, polarized in a plane perpendicular to Z Z. Carhazotate of Potash, — Prismatic. MM= 89°36' AM = 55 12 LL = 40 20 A L = 60 50 The crystals are elongated in the a direction of the axis of the zone A M, and the faces L are so small that their position cannot be accu- rately ascertained. The doubly re- fractive energy of this salt is pro- bably greater than that of any other crystal. When yellow light is refracted through the faces M M, the minimum devia- tion of a ray polarized in the plane MA M is 51° 40'. Hence the ratio of the velocity of light in air to its velocity within the crystal is 1*527, for a ray in the plane MAM polarized in the same plane. For a ray traversing the crystal in the direction Y Y, and polarized in a plane perpendicular to MAM, this ratio is found to be nearly 1 -95. M. Cauchy's View of the Undulator-y Theory of Light, 107 The cabinet of Natural History under the direction of M. Voltz, at Strassburg, contains an alloy of copper and tin in acicular crystals, the composition of which, according to the analysis of M. Roth, is expressed by the formula 2 Sn Cu. Some of these crystals, which were given me for the purpose of having their form determined, are regular six-sided prisms, cleavable with some difficulty in a direction perpendicular to the axis of the prism. No rhombohedral faces or cleavage could be detected. XVII. An Abstract of the essential Principles of ^. Cauchy's View of the Undtilatory Theory,, leading to an Explanation of the Dispersion of Light ; with Remarks. By the Rev, Baden Powell, M.A., F.R.S., Savilian Professor of Geo- metry^ Oxford. [Continued from p. 25.] Integration of the Equations of Motion, TN order to proceed to the integration of the equations (12.), ■*• M. Cauchy adopts the principle, (or at least one which comes to the same thing,) that whatever may be the values of the functions ^ ») 5 which will verify those equations, they may always be developed in some serieses of algebraic functions of xy z, which may be considered as formed by adding together the serieses for the sine and cosine of quantities involving those functions of xy z, with certain arbitrary quantities uvw, and certain coefficients d e f g h i, functions of /. Using the sym- bol i' to signify the sum of a number of such terms, we shall thus have J = 2!{d cos {uxi-vy-\-wz) + g sin{ux + vy-\-wz)} ri = S{e cos (ux-\-vy-\-wz) -i- h sin {ux + vy + wz)} {IS.) ?= Su cos (ux-\-vy-i-w;::) + i sm (ux-\-vy + w z)} Now the arbitrary quantities n v w may be assumed, so that we have w 1 j._a, J- -0, ^ ^ ., ^ ^^^^ and a^ + b' + c^ = 1 ; that is, these quantities may represent the cosines of the in- clinations to the three axes, of a line passing through the origin, which we will call O P. And if we write, for abbreviation, ax -\- by -\- cz = g, (15.) P2 108 Prof. PowelPs Abstract o/M. Cauchy's then, g will be the perpendicular distance of the point x y z^ from a plane passing through the origin whose equation is ax-{-by-^c^ = 0. (16.) The equations (13.) will by this notation become f = ^ [d cos k g + g sin ^ §] >) = 5* [e cos^g + h sin A- ^] (17.) ^ = -5* [ f cos kq -\- i smk q] Now to determine the coefficients d e, &c., in functions of the variable / and the arbitrary constants k ah c, we may pro- ceed as follows : Let 5 be the angle formed by r with O P, then cos 8 = a cos a -\- b cos /3 + c cos y. , (180 Also from the values of Ax, &c. (2.) joined with that of q (15.) we have, taking the corresponding small increments, Aq = aAx -|- bAy + cAz — r cos 8. (19.) Also we shall find by a simple trigonometrical process A cos /t' § = — 21 sm^ j cos k q — sin [k r cos 8) sin k q And in exactly the same manner )- (20.) .. -7 o / • 9 ^^ ^' cos 8 \ . - A sm kq = — 2 1 sm^ ~ \ sm k q -\- sin {k r cos 8) cos k q. In order to simplify the subsequent investigation, we will in the first instance consider the sums of terms (17.) as each reduced to a single term, or take ^ = d cos k q -\- g sin ^ ^, which on differentiating with respect to q gives -1 — = A: [ — d sin ^ ^ + g cos k q) ; and substituting these values in the corresponding formula A f =8 d A cos k q -\- g A s\u kq, we shall find the value of that quantity, and by similar means those of the others analogous to it, ,. *. • -o { k r cos 8\ sin (kr cos ^) d^ Ag = -2 f s.„^ ( -^— ) + ~^Tc HJ >(21.) View of the Undulatory Theory of Light. 109 We should now have to substitute these values in the fun- damental equations (12.), and thus obtain expressions involv- d^ ing f -7^, &c., which would obviously extend to some length. But even without actually going through this process at length, we shall easily perceive a principle of simplification arising out of the form which we shall at once see certain parts of the expressions must take, as follows : 1st. In the forms (21.), all the terms involving f >j ? have in their coefficients the square of the sine of a function of 8, and these terms, when introduced as multipliers in (12.), are in the first member uncombined with any other functions of the an- gles a /3 y 8 ; and in the second members are combined with the squares of the cosines of the angles ; that is, in every case these terms are of even dimensions, 2ndly. All the terms involving the differential coefficients of f )j ^ have, in (21.), for coefficients the si7ie of a function of 8 ; and these in the multiplication also, in the first member, stand uncombined with any other such function ; and in the second, combined with the squares of the cosines ; that is, in every case they are of odd dimensio?is. Also, it appears from the original construction and from (18.) that the cosines of a /3 y S are all positive or all nega- tive together. Now, in taking the sum of a number of terms (indicated by the symbol S), it is evident in the former of the above two cases that all those terms will be positive whatever be the signs of the cosines. In the second case, for the same reason, the terms will be positive or negative according to the change of sign in the cosines. If, then, we suppose in such a sum, half the terms corre- sponding to positive, and half to negative values of the co- sines, we shall find that the coefficients of all the terms in the second case will disappear, whilst in the first case they will re- main. The whole expression will thus be reduced to the terms involving 0 >] ? only. This last supposition is precisely that of a physical condi- tion which we shall have no difficulty in allowing, viz. that in the state of equilibrium the masses of the molecules tn 7n' m"y &c., are two and two equal, and distributed symmetrically on each side of the molecule m on straight lines passing through m. This obviously gives the cosines for half the molecules positive, and for half negative. In such a case then we shall have the general equations of motion reduced to a considerably simplified form ; or, for ab- no Prof. PowelPs Abstract ofM. Cauchy's breviation, writing the sums of the coefficients derived from those terras of (li^.) which involve cos^ a, cos* /3, cos^ y, re- spectively L, M, N ; and those which involve cos j3 cos y, cos y cos a, cos a cos /3, respectively P, Q, R, those equations are reduced to the following : dt^ dt^ d^ dt^ = -[R0 + M,,+P?]> = - [Q0+P>j + N?] (22.) These equations enable us at the end of the time /, to deter- mine the three functions f >) ? ; which is, in fact, done, if we have determined the six functions d e f g h i; and this we can effect by means of the initial values of these functions, and their differential coefficients with respect to t. Writing these initial values of the functions by subjoining (o), and those of their dif- ferential coefficients by subjoining (1.), we shall have by the formula (17.), supposed reduced to a single term, 00 = do cos kq + go sin ^ ^ ^ >3o = Cq cos ^ ^ + ko sin k § ^ = fo cos kg -\- io sin kg 01 = dj cos kg + gi sin ^ ^ >ji = Cj cos kg -f ki sin^^ > (23.) ?i = fj COS kg + i, sin ^ ^ In order, by means of these values corresponding to / = 0, to deduce those corresponding to any value of ^, we must pro- ceed to the following considerations relative to the coefficients. Let the arbitrary quantities A B C be assumed as the co- sines of the angles which a certain line OA through the origin forms with the positive semiaxes ; or in other words, so that we have A^ + B^ + C^ = 1 and the line O A is represented by the equations •^ _ ^ _ ^ X "■ B^ ■" IT' Also, if we suppose 8 = A0 + B)3+C?, the value of a will give the displacement of the molecule m in a direction parallel to the line OA, and positive or negative according to the direction of that line. / (24.) (25.) (26.] View of the Undulatory Theory of Light. Ill Again, if the quantities ABC be so chosen that on multi- plying the first term of each member of the equations (22.) by A, the second by B, and the third by C, we have LA + RBh-QC_ RA + MB + PC _ QA + PB + NC,_. -^ ^b~"~~ - C ^^^'^ and write these equal to s*, then, on differentiating the equa- tion (26.)jand substituting the values from equation (22.), we shall find the second differential coefficient to be the remark- able form dU _ 3 . 'TP ~ ~' ' ^^^'^ From (27.) it is evident that we have three values of s^ cor- R C • responding to three systems of values of the ratios -^, —t- ' and consequently there are three straight lines with either of which the line O A may coincide ; and the same equations en- able us to determine these lines, for they evidently coincide in form with those mentioned in the preliminary article. We can deduce the same equation of the third degree, which for reference we will call (29.); and consequently the three lines OA'OA"OA'" are identified with the three axes of the surface of the second degree represented by the equation there assumed, involving as coefficients the quantities L M N, &c., and which we will call (30.). If it be an ellipsoid, the three values of 5^ are equal to the squares of the three semiaxes of the ellipsoid. These considerations then enable us to assign the displace- ment of m at the end of the time /, in directions parallel to three determinate lines at right angles. Let these three dis- placements be expressed by accenting the letters in equation (26. )> or let us suppose «' = A'f + BS + C? ^ 8" = A"f + B"), + C"? L (31.) «'" = A"'f + B"'>3 + C"? J In each set of the coefficients the relation (24.) holds good ; also, since the lines are at right angles, we have A'A" + B'B" + C'C" = 0 ^ A"A'"+ B"B'"+ C"C"'= 0 A' A'" + B'B'" + C'C" = 0 Hence we deduce from (31.) ^ = X'b + A" 8"+ A'" 8'" rj = B'8' + B"8" + B"'8"' y (33.) (32.) 112 M. Caiichy's View of the Ufidulatory Theory of hight. Now, writing bq »! ^^r the initial values of a and -jv j we Oi Z have «o = A^o + B>3o + C?o (34..) »i = A^i + B>ji + C?i; (35.) or, substituting the values of ^q ^j, &c., from (23. )» these forms become 8o= [cloA + eoB + foC]cos^§+[goA + hoB + ioC]sin^g = ^ (g) (36.) «! = [d,A + eiB + fiC]cos^^ + [giA + hiB + iiC]sinA'^ = ^ (§), (37.) using the last symbols to designate the forms of these func- tions of q. The form of the expression (28.) shows us at once that its integral must be a trigonometrical function, which it will easily be seen must take the following form, involving as coefficients the initial values sin 5^ 8 = 80 cos St -^ 8i— , (38.) or, what is the same thing, 3 = 8o cos st + 8i /o cos s t dt, (39.) If we here substitute the values of «q gj and the trigonome- trical values of the resulting products, and also write we shall at length deduce an expression, which, in compari- son with equations (36.) (37.), may, by the same notation, be expressed thus, (carefully observing that no greater gene- rality is implied than belongs to (38.) and (39.) ): 'OS {q -r ft t) ^- ts {g-^nt) 2 ~ ^ n^ n{g-^nt)-^n{g-nt) ^^^ Jo 2 (40.) the form being the same for each of the values «' a'' «'" corre- sponding to the three positive values of 5-, involving respec- tively n' ir a'" and A' M' A'", &c. If these values of b\ &c , be substituted in equation (33.), we have ^ >5 ^ in func- tions of § and /, which satisfy the two conditions of the values ^0, &c., when ^ = 0, and of the equations (22.) for any value of^. Also the velocity co of the molecule at the end of any time t On the Existence of Titanic Acid in Hessian Crucibles. 113 in the directions of the axes, and of the three lines o A re- spectively, will be d^ dxi d ds" d8^ d^ dt dt dt dt ~dt dt' and, we have also -@)%(S)%d-i)'-(^y-(S')"Mir^)' (41.) [To be continued.] XVIII. On the Existence of Titanic Acid in Hessian Crucibles, By Mr. R. H. Brett and Mr. Golding Bird. To the Editors of the Philosophical Magazine and Journal, Gentlemen, Tjy HILE repeating some experiments lately published on ^ * the presence of titanium in organic matter, especially in the renal capsules*, we observed that when an alkaline car- bonate was exposed to heat in Hessian crucibles, a fused mass was obtained, which was yellow while hot, but white and opake when cold; on dissolving this fused mass in dilute hydro- chloric acid and mixing the solution with hydrosulphuret of ammonia, a deep olive green precipitate was obtained, which, when dried and ignited, yielded a white powder, insoluble in the dilute acids. These reactions so exactly resembling those yielded by titaniferous substances, we were induced to sus- pect the presence of titanium in the clay of which the crucibles were formed. To determine this with accuracy we undertook an analytical examination of the several varieties of Hessian crucibles usually met with, and we found them all to consist of (in variable proportions) silicic acid, titanic acid, alumina, and peroxide of iron, with traces of magnesia and manga- nese, and occasionally of lime. The quantity of titanic acid present differed considerably in different specimens, in some not amounting to more than 3{ or 4f per cent., and in some few even to as much as 25 or 30 : it was exceedingly rare to meet with so much as 25 per cent. ; those crucibles that contained that quantity were generally small, very thin, brittle, and studded with numerous black semimetallic-looking specks. The quantity of peroxide of iron present was small compared to that of titanic acid, and they were by no means in the proportions in which they exist either in the iserine or in the menachanite, to the presence of which * See our last vokime, p. 398. — Edit. ThirdSeries. Vol. 6. No. 32. Feb. 1835. Q 1 14 Mr. R. H. Brett and Mr. Golding Bird on the forms of titaniferous sand we at first were inclined to believe the presence of titanium was owing, this opinion appearing to be corroborated by our noticing that in those crucibles in which the black specks (above referred to) were most nu- merous, the quantity of titanium appeared to be the greatest. The source of that metal in these crucibles must still remain a question. We subjoin an outline of the process we followed in the analysis of these crucibles, as we believe that the (hitherto unlooked for) presence of titanium in these articles of che- mical research to be of some importance in analytical che- mistry. 1. A portion of a crucible was reduced to fine powder in an agate mortar, then carefully mingled with three times its weight of carbonate of potass in a platinum crucible; the lat- ter was then exposed to a red heat until all effervescence had ceased ; the heat was then raised to whiteness so as to ensure perfect decomposition of the silicious body. The fused mass while hot was yellow; on cooling, however, it became greyish and opake. 2. The crucible being wiped from the adhering ashes was placed in a glass cylinder, covered with distilled water ; hy- drochloric acid was then poured in and the cylinder closed with a watch-glass. After some hours the fused mass was en- tirely dissolved or loosened out of the crucible ; the latter was removed, rinsed with distilled water, the washings being added to the solution, which was nearly limpid, (a few light flakes of silicic acid were in suspension,) a little nitric acid was added, and the whole evaporated to dryness ; the residue was diffused through a considerable quantity of distilled water and thrown oji a filter: the silicic acid thus separated was washed with distilled water until the last portions of fluid ceased to affect nitrate of silver ; it was then dried, ignited, and weighed. 3. The filtered liquor with the washings was evaporated over a steam-bath to half a pint, a few grains of sugar added (to reduce the manganese to protoxide and thus render it so- luble in an ammoniacal salt), and ammonia poured in to super- saturation: a copious gelatinous precipitate fell, which was collected on a filter, washed with a dilute solution of muriate of ammonia, and thoroughly dried on a sand-bath. 4. The dried precipitate thus obtained, consisting of titanic acid, alumina, and peroxide of iron, was boiled in hydrochlo- ric acid, which dissolved the alumina and iron ; the insoluble titanic acid was then washed, ignited, and weighed. 5. The acid solution of alumina and iron was mixed with an excess of caustic potass and boiled: the peroxide of iron thus separated was then ignited and weighed. Existence of Titanic Acid in Hessian Crucibles, 115 6. The alumina was next obtained by boiling the alkaline solution with an excess of muriate of ammonia for some time: the resulting gelatinous precipitate was washed, ignited, and weighed. 7. The liquor (3.) from which the titanic acid, alumina, and peroxide of iron were separated, contained traces of magnesia and manganese. The results obtained by examining several specimens, dif- fered very considerably, as may be seen by comparing together the following results of four analyses : Silicic acid Titanic acid Alumina Ptroxide of iron ^^agnesia Oxide of raansanese Loss 1st. 2nd. 3rd. 4th. 75-1 70-0 680 660 3-5 53 80 210 150 18-7 18-0 8-0 2-8 30 50 40 1-4 •8 0-6 1-2 1 0-3 > traces 98-6 98-8 99-3 990 1-4 1-2 •7 1- 100* 100- 100- 100- In a very few specimens we have found the titanic acid to be present in very minute quantities, and in one or two only we could not succeed in detecting any. It is a very difficult matter to free the titanic acid from the peroxide of iron, the last traces of which adhere exceedingly obstinately to the acid; the process recommended by Berzelius, viz. adding tartaric acid to the acid solution of the mixed oxides and the subse- quent precipitation of the iron by hydrosulphuret of ammonia, by no means succeeding perfectly. The use of oxalic acid for the purpose of precipitating the titanium and leaving the iron in solution is not more efficient, as the precipitate is found to be contaminated with a considerable quantity of peroxide of iron. The following is the process we prefer for the purpose of obtaining the titanium, free from iron. Ignite a mixture of carbonate of potass and powdered Hessian crucibles; digest the mass thus obtained in warm water for some time: this aqueous solution yields a very slight grass-green tinge with hydrosulphuret of ammonia. Dissolve the portion insoluble in water in hydrochloric acid, with the assistance of a gende heat ; dilute and filter the acid solution and wash the residue on the filter ; when the acid has almost entirely passed the filter, the washings become opaline. The filtered fluid is then to be nearly neutralized with ammonia, and hy- drosulphuret of ammonia added: a deep green precipitate falls, which is to be collected on a filter and washed with a di- Q2 116 Mr. Lubbock on some Elementary lute solution of muriate of ammonia. This precipitate is almost black in the mass, but when spread over the surface of white porcelain or paper, it appears of a fine sap-green ; by exposure to the air it becomes nearly white on the surface, ■which discoloration speedily extends to some depth, (if all the hydrosulphuret has not been washed away, this change does not take place until after some time) ; it is then to be dried on a sand-bath and digested in weak hydrochloric acid, by which almost all the sulphuret of iron is removed ; the inso- luble portion is then to be again dried and ignited, in a pla- tinum capsule over the circular-wick spirit-lamp (or if in con- siderable quantity, on a platinum tray in a small muffle) ; a cream-coloured powder is thus obtained, still containing a minute portion of iron, which may be got rid of by mixing it with muriate of ammonia, and exposing it for some time to a temperature below ignition. The titanic acid thus procured is tolerably pure. In conclusion we would wish to remark that titanium ap- pears to be more generally diffused through the mineral kingdom than is generally stated (in chemical works), as ap- pears particularly from the following passage in Thenard's Traite de Chimie : " Le deutoxide de fer se rencontre sous forme de sables. Ces sables contiennent ordinairement de I'oxide de titane ou de Poxide de chrome en combinaison avec Toxide de fer. M. Descotils a retire jusqu'a 30 parties de ti- tane de 100 parties de sables ferrugineux de Saint-Quay, de- partement des Cotes du Nord. M. Robiquet I'a rencontre dans le deutoxide de fer des roches steatiteuses de la Corse." Guy's Hospital, Dec. 26th, 1834. XlX. On some Elementary Applications of Khei^s Theorem. By J. W. Lubbock, Esq,, KP, ^ Treas. R.S* ABEL, in the third volume of Crelle's Journal, gave a theorem, which constitutes one of the most remarkable discoveries ever made in analysis, by which the methods of finding the sum of certain definite integrals were greatly ex- tended. Cut off in the prime of lifef, it was not given to the mathematician of Christiania to pursue the career which is opened to analysts by the theorem in question, or to illustrate its application by examples. This has been done to a certain extent by Legendre in the third Supplement of his work en- titled Theorie des Fonctions Elliptiques %, As, however, no no- tice of this theorem has yet appeared in any work in the En- * Communicated by the Author. f (.See Phil. Mag. and Annals, N.S. vol. vii. p. 77- — Edit.] X [See Lend, and Edinb. Phil. Mag., vol. iv. p. 143.— Edit.] Applications of AbePs Theorem, 1 1 7 glish language, to my knowledge, the following examples of its application to some of the simplest cases which can be pro- posed are here offered, with a view of attracting attention to an important analytical discovery*. Legendre has applied Abel's theorem to the integral dx /-. The subject of the first example here detailed is the integral dx f- 4/1-^ which may, in fact, be reduced to an elliptic integral of the first kind ; and thus, through the well-known integral due to Euler, a confirmation may be easily obtained, in this instance, of the result found by the method of Abel. The subject of the second example is dx f which cannot in general be reduced to an elliptic integral. Here I have chosen for the equations of condition between the limits x^^ jr^, x^;^ &c., equations similar to those employed by Mr. Talbot in his paper on the sum of three arcs of the equilateral hyperbolaf. I have also applied the method of Abel to the integral x^dx f Vl+o^*' and deduced therefrom the theorem given by Mr. Talbot in the paper to which I have referred. The theorem of Abel is as follows : " Soit <^x une fonction entiere de .r, decomposee d'une maniere quelconque en deux facteurs entiers ^jj x et ^^ x^ en- sorte que ^ x = ^■^x,<^^x» ^oilfx une autre Ibnction entiere quelconque et **-y(*-«)v/(<^"^)' ou a est une quantite constante quelconque. Designons par Aq, «!, %, .... ; Cq, q, Cg, des quantites quelconques dont Tune au moins soit variable. Cela pose, si Ton fait * Professor Jacobi says, ** Wir halten es, wie es in einfacher Gestalt ohne Apparat von Calcul den tiefsten unci umfassendsten mathematischen Gedanken ausspricht, fUr die grdsste mathematische Entdeckiing unsrer Zeit, obgleich erst eine kiinftige, vielleicht spate, grosse Arbeit ilire ganze Bedeutung aufweisen kann. — Crelle's Journal, vol. viii. p. 415. t [ A notice of Mr. Talbot's paper will be found in Lond. and Edinb. Phil. Mag. vol. iv. p. 225.— Edit.] 118 Mr. Lubbock on some Elemenlary = A {x—x^) [x—x<^{x—x^ ('^— <37^)> ou A ne depend pas de x^ je dis qu'on aura ^ Jit , C(ao+ai«+»»»+^n«") a/(^i«)+(co+Ci«4->.-+c>» «"") V(^g«)? oii C est une quantite constante et r le coefficient de — dans le developpement de la fonction fx , ^(ao+aiX + ...+anx")A/(^ia:)+(Ci+Cig+.»+^ma?"*)V(^2x)^ suivant les puissances descendantes de x, Les quantites Sj, Sg, 6^ sont egales a+l ou a— 1, et leurs valeurs dependent de celles des quantites x^, x<^ x ^" Suppose generally, fijT = aQ-\-a^x + ac^x^ +fl„j:" ^^X = Cq +C^X+CciX'^ +c^x*". The values of sj, gg, 63 e/a, are not arbitrary, they de- pend upon the magnitude of x^, x^ j;^, and this is deter- mined by the equation $x ^/ /3 8in2^ J ^l-A-3 ^ ^ J ^X- The equation 3 = (1— ^i) (1— ^2) giv^s • -1 = 1-33333 and ^ — 1-83333, &c. (See theTable of the value* 3 o of log Ta, Thiorie des Fortciiom EUiptiqties, vol. ii. p. 493.) Applications of AheVs Theorem. 121 tan' -I' tan' I?- = 1 <^l + ^2 = ""• I shall now consider the integral p dx J -v/l+a:"' which cannot, except in certain cases, be reduced to an elliptic integral. Suppose ^/\■\■x^ = 's/'^x^ i+a;" = 4^1 or, ^,^x = 1 fi a: = 1, ^2^ = 1+^1 ^ • 1 +;r»- (I +c^xY = X (;r«-'- £!lf2'3Y-^^Vl^ + a^j a:*2 ^3 ... ^n— 1}> the upper sign to be taken if n is an uneven number, and the lower if jris even, x^^ x^^ x^ ... Xnr-\ being the roots of the equation ^n-i _ Pa; + Q = 0 r> **i -^a «^3 ••••*' n— .1 /. - ^ , together with the other conditions implied by the nature of the equation ^.«-i _ p^ 4. Q == o ^1 - + 2 • a*!, jTg, 0^3 ... a"„_i, being subject to the above condition «>y^i^ + nhj^ + .^. /^:!ii^ *^0'/l+*" •^0^1+'*"* ^o'/l+*» = constant. Also, s^P^^M^ + ../:i££f + .^^.ffmlJ^ = constant. K coefficient of — in the development of L \/l+A"j according to descending powers of x. Third Series, Vol. 6. No. 32. Pe^. 1835. R 122 Mr. Lubbock on some Elemefitary Suppose w = 4, then the equation x*^^ — Px+ Q = 0 has only three roots, x^, ar^, x.^ x^ -\- x^ -\- x^ =: 0 JT| x^ x^ Xi X^ •+• -^2 "^S "•" '''I '*^3 ^ '"' T 111 Xi Xn Xo or, — + — + — = \ » Xs x^ x^ 4. These are Mr. Talbot*s equations of condition in the paper to which I have referred. Since e^ x/TTx[* = l-^c^x^ c, = Sj V 1 + 0^1 — 1 = -^—^ — Xi Xa X^ 2 " ^1^ •X^o ~\ *^o *— ■"" w If x^ Xs = 2A x^ and x^ are found by solving the quadratic x^ — xxi+2A=zO when ^1 is given. Making Xi = 2 — = '5 ^i = — 1 I find a-g = - 2-88721 — = - -346355 ^s = + 1 x^ •88721 — = 1-12713 63=—! X Making x^ = 5 — = '2 gj = — 1 I find ^2 = - 5-38645 — = — -185651 63 = + 1 Xq = -38645 — = - 2-58765 63 = -1 Xg In order to obtain convergent expressions for the integral required, I make TT? = «. then /> dx i 3 4 , 3.7 „ , 3.7.11 1' , „ /TT^* = " + *T5 »+ 47879 "' + 4.-8.V2713" ' +«"=• /: Applications o/' Abel's Theorem. 123 If this series be called /7, the integral I find from this series for the values of the integral from :f = 0 to ;r = 2, \I/' '49695 0 X = 0 to a; = —2'SSTn, -^ —■ + -34.586 X = 0 to a: = 5, ^/'-^ — -199968 X = 0 to or = —5-3864.5, —4'' -^ + '185628 In order to have a convergent series for the value of the integral from ^ = 0 to ^ = -88721, I make 4 X / dx _ ^, i , 3z/| 3.72/| . 3.7.11?/ V' \/l+x'' 4.5 ^4.8.9 ^4.8.12.13 ^ and I find for the integral in question, the number -f- -84288. The integral from ^ = 0 to ^ = -38645 may be found at once from the expression dx x^ 1.3 a:'' 1 . 3 . 5 ^'^ v/l+^* 2.5 2.4.9 2.4.6.13^ /- and I obtain for this integral the number + -38561. It appears in this case that the constant on the right hand side of the equation equals — 2 \(/'i, and •49695 + -34586 — -84288 = 0 nearly* -19968 + -185624 — -38561 = 0 according to the general theorem. It may be proper to men- tion, that the transformations adopted in order to procure con- vergent series for the integrals required, are all taken from Legendre's work. The equations of condition between the quantities x^, x^, x^ &c., may be varied to an almost indefinite extent: those which I have adopted in the last example are the same which were used by Mr. Talbot, and through which he obtained a * The theorem is of course rigorous, but it can only be verified ap- proximately in numerical examples. R2 124 On some Elemeiitary Applications o/* Abel's Theorem. theorem relative to the sum of three arcs of an equilateral hy- perbola. The coefficient of — in the development of x^ lo J ^1-fr-^ I = coefficient of — in the development of X ' "1 - M[,-K^.,|,_^,,^.}| — JTj 0*5 X^, Hence (seep. 118, line 5,) f, / — ==r + £a / — + g^ / — =^ — = constant T" ^j X(^ Xg /vi±z dx^-^ ^^^" + 2 r^'jf, , ^ x" X J -v/l+o;* and, since = — = V c. ' X X X ^ 0 "^ 0 *^ 0 ^ 111 Sx, ajo Xq = —^ " -:;r - 'o - + 2^^ x^Xg + constant = — jL'i ^2 X3 + constant, which is Mr. Talbot's theorem. In the numerical examples offered in this paper, I have only carried the approximation as far as could be done con- veniently by the common tables of logarithms, that is, to six places of decimals. If L be the logarithm of the number N, L \-x the loga- rithm of the number N+i/, Dr. Faraday's Experimental Researches in Electricity, 125 p being the Napierian logarithm of the base. log 3/ = log (Npa:) + log /"l + -|^ + |-|- + &c.J- = log (Npx) + -|- + &c. Also a: = — /^=^+&c.V log p = -36221 56887. With the help of these expressions, and the table of Brfgg's logarithms to sixty-one places of decimals given in Callet, the approximations may be carried much further if desired. XX. Experimental Researches in Electricity, — Eighth Series, By Michael Faraday, D.C.L. F,R.S.Fullerian Prof. Chem, Royal Institution^ Corr, Memb. Royal and Imp, Acadd, of Sciences^ Paris, Petershurgh, Florence, Copenhagen, Berlin^ Sfc, Si^. [Contiiiued from p. 45 : with an Engraving.] 915. r>ETURNING to the consideration of the source of ■•-*• electricity {878, &c.)) there is another proof of the most perfect kind that metallic contact has nothing to do with the production of electricity in the voltaic circuit, and further, that electricity is only another mode of the exertion of che- mical forces. It is, the production of the electric spark before any contact of metals is made, and by the exertion of pure and unmixed chemical forces. The experiment, which will be described further on (956.), consists in obtaining the spark upon making contact between a plate of zinc and a plate of copper plunged into dilute sulphuric acid. In order to make the arrangement as elementary as possible, mercurial surfaces were dismissed, and the contact made by a copper wire con- nected with the copper plate, and then brought to touch a clean part of the zinc plate. The electric spark appeared, and it must of necessity have existed and passed before the zinc and the copper were in contact. 916. In order to render more distinct the principles which 126 Dr. Faraday's Experimental Researches in Electricity, I have been endeavouring to establish, I will restate them in their simplest form, according to my present belief. The electricity of the voltaic pile (856. note) is not dependent either in its origin or its continuance to the contactof the metals with each other (880. 915.). It is entirely due to che- mical action (882.), and is proportionate in its intensity to the intensity of the affinities concerned in its production (908.); and in its quantity to the quantity of matter which has been chemically active during its evolution (869.)- This definite production is again one of the strongest proofs that the elec- tricity is of chemical origin. 917. As volta-electro-generation is a case of mere chemical action, so volta-electro-decomposition is simply a case of the preponderance of one set of chemical affinities more powerful in their nature, over another set which are less powerful ; and if the instance of two opposing sets of such forces (891.) be considered, and their mutual relation and dependence borne in mind, there appears no necessity for using, in respect to such cases, any other term than chemical affinity, (though that of electricity may be very convenient,) or supposing any new agent to be concerned in producing the results; for we may consider that the powers at the two places of action are in di- rect communion and balanced against each other through the medium of the metals (891.), fig. 4, in a manner analogous to that in which mechanical forces are balanced against each other by the intervention of the lever (1031.). 918. All the facts show us that that power commonly called chemical affinity, can be communicated to a distance through the metals and certain forms of carbon ; that the electric cur- rent is only another form of the forces of chemical affinity ; that its power is in proportion to the chemical affinities pro- ducing it; that when it is deficient in force it may be helped by calling in chemical aid, the want in the former being made up by an equivalent of the latter ; that, in other words, the forces termed chemical affinity and electricity are one and the same. 919. When the circumstances connected with the produc- tion of electricity in the ordinary voltaic circuit are examined and compared, it appears that the source of that agent, always meaning the electricity which circulates and completes the cur- rent in the voltaic apparatus, and gives that apparatus power and character (947- 996.), exists in the chemical action which takes place directly between the metal and the body with which it combines, and not at all in the subsequent action of the substances so produced with the acid present*. Thus, • WoUaston, Philosophical Transactions, 1801, p. 427, [or Phil. Mag., vol. xi., p. 206.— Edit.] Source of Electricity in the Voltaic Apparatus. 127 when zinc, platina, and dilute sulphuric acid are used, it is the union of the zinc with the oxygen of the water which de- termines the current; and though the acid is essential to the removal of the oxide so formed, in order that another portion of zinc may act on another portion of water, it does not, by com- bination with that oxide, produce any sensible portion of the current of electricity which circulates ; for the quantity of elec- tricity is dependent upon the quantity of zinc oxidized, and in definite proportion to it : its intensity is in proportion to the in- tensity of the chemical affinity of the zinc for the oxygen under the circumstances, and is scarcely, if at all, affected by the use of either strong or weak acid (908. )• 920. Again, if zinc, platina, and muriatic acid are used, the electricity appears to be dependent upon the affinity of the zinc for the chlorine, and to be circulated in exact proportion to the number of particles of zinc and chlorine which unite, being in fact an equivalent to them. 921. But in considering this oxidation, or other direct ac- tion upon the metal itself, as the cause and source of the electric current, it is of the utmost importance to observe that the oxygen or other body must be in a peculiar condition, namely, in the state of combination', and not only so, but li- mited still further, to such a state of combination, and in such proportions as will constitute an electrolyte (823.). A pair of zinc and platina plates cannot be so arranged in oxygen gas as to f)roduce a current of electricity, or act as a voltaic cir- cle, even though the temperature may be raised so highly as to cause oxidation of the zinc far more rapidly than if the pair of plates were plunged into dilute sulphuric acid, for the oxy- gen is not part of an electrolyte, and cannot therefore con- duct the forces onwards by decomposition, or even as metals do by itself. Or if its gaseous state embarrass the minds of some, then liquid chlorine may be taken. It does not excite a current of electricity through the two plates by combining with the zinc, for its particles cannot transfer the electricity active at the point of combination, across to the platina. It is not a conductor of itself, like the metals ; nor is it an elec- trolyte, so as to be capable of conduction during decomposi- tion, and hence there is simple chemical action at the spot, and no electric current *. * I do not mean to affirm tiiat no traces of electricity ever appear in such cases. What I mean is that no electricity is evolved in any way, due or related to the causes which excite voltaic electricity, or proportionate to them. That which does appear occasionally is the smallest possible fraction of that which the acting matter could produce if arranged so as to act voltaically, probably not the one hundred thousandth, or even the millionth part, and is very probably altogether different in its source. 128 Dr. Faraday's Expei'imetiial Researches in Electricity, I 922. It might at first be supposed that a conducting body, not electrolytic, might answer as the third substance between the zinc and the platina; and it is true that we have some such capable of exerting chemical action upon the metals. They must, however, be chosen from the metals themselves, for there are no bodies of this kind except those substances and charcoal. To decide the matter by experiment, I made the following arrangement. Melted tin was put into a glass tube bent into the form of the letter V, fig. 6, (Plate I.) so as to fill the half of each limb, and two pieces of thick platina wire, /?, w, in- serted, so as to have their ends immersed some depth in the tin ; the whole was then allowed to cool, and the ends jp and *iso connected with a delicate galvanometer. The part of the tube at X was now reheated, whilst the portion y was retained cool. The galvanometer was immediately influenced by the thermo-electric current produced. The heat was steadily in- creased at jr, until at last the tin and platina combined there ; an effect which is known to take place with strong chemical action and high ignition ; but not the slightest additional effect occurred at the galvanometer. No other deflection than that due to the thermo-electric current was observable the whole time. Hence, though a conductor, and one capable of ex- erting chemical action on the tin, was used, yet, not being an electrolyte^ not the slightest effect of an electrical current could be observed (947.). 923. From this it seems apparent that the peculiar charac- ter and condition of an electrolyte is essential in one part of the voltaic circuit ; and its nature being considered, good reasons appear why it and it alone should b6 effectual. An electrolyte is always a compound body ; it can conduct, but pnly whilst decomposing. Its conduction depends upon its decomposition and the transmission of its "particles in directions parallel to the current ; and so intimate is this connexion, that if their transition be stopped, the current is stopped also; if their course be changed, its course and direction changes with them ; if they proceed in one direction, it has no power to proceed in any other than a direction invariably dependent on them. The particles of an electrolytic body are all so mutually con- nected, are in such relation with each other through their whole extent in the direction of the current, that if the last is not disposed of, the first is not at liberty to take up its place in the new combination which the powerful affinity of the most active metal tends to produce ; and then the current it- self is stopped ; for the dependencies of the current and the decomposition are so mutual, that whichever be originally de- termined, 7. e, the motion of the particles or the motion of the Oxidation of the Zinc the Source of Electricity. 129 current, the other is invariable in its concomitant production and its relation to it. 924. Consider, then, water as an electrolyte and also as an oxidizing body. The attraction of the zinc for the oxygen is greater under the circumstances, than that of the oxy- gen for the hydrogen; but in combining with it, it tends to throw into circulation a current of electricity in a certain di- rection. This direction is consistent (as is found by innumer- able experiments) with the transfer of the hydrogen from the zinc towards the platina, and the transfer in the opposite di- rection of fresh oxygen from the platina towards the zinc ; so that the current can pass in that one line, and, whilst it passes, can consist with and favour the renewal of the conditions upon the surface of the zinc, which at first determined both the combination and [the] circulation. Hence the continuance of the action there, and the continuation of the current. It there- fore appears quite as essential that there should be an elec- trolyte in the circuit, in order that the action may be trans- ferred forward, in a certain constant direction, as that there should be an oxidizing or other body capable of acting directly on the metal ; and it also appears to be essential that these two should merge into one, or that the principle directly active on the metal by chemical action should be one of the ions of the electrolyte used. Whether the voltaic arrangement be excited by solution of acids, or alkalies, or sulphurets, or by fused substances (476.), this principle has always hitherto, as far as I am aware, been an anion (943.) ; and I anticipate, from a consideration of the principles of electric action, that it must of necessity be one of that class of bodies. 925. If the action of the sulphuric acid used in the voltaic circuit be considered, it will be found incompetent to pro- duce any sensible portion of the electricity of the current by its combination with the oxide formed, for this simple reason, it is deficient in a most essential condition; it forms no part of an electrolyte, nor is it in relation with any other body present in the solution which will permit of the mutual transfer of the particles and the consequent transfer of the electricity. It is true, that as the plane at which the acid is dissolving the oxide of zinc formed by the action of the water, is in con- tact with the metal zinc, there seems no difficulty in consider- ing how the oxide there could communicate an electrical state, proportionate to its own chemical action on the acid, to the metal, which is a conductor without decomposition. But on the side of the acid there is no substance to complete the cir- cuit: the water, as water, cannot conduct it, or at least only so small a proportion that it is merely an incidental and al- Third Series, Vol. 6. No. 32. Feb. 1835. S 130 Dr. Faraday *s Experimeiital Researches in Electricity, most inappreciable effect (970.); and it cannot conduct it as an electrolyte, because an electrolyte conducts in consequence of the mutual relation and action of its particles ; and neither of the elements of the water, nor even the water itself, as far as we can perceive, are ions with respect to the sulphuric acid (848.)*. 926. This view of the secondary character of the sulphuric acid as an agent .in the production of the voltaic current, is further confirmed by the fact, that the current generated and transmitted is directly and exactly proportional to the quan- tity of water decomposed and the quantity of zinc oxidized (868. 991.) : and is the same as that required to decompose the same quantity of water. As, therefore, the decomposition of the water shows that the electricity has passed by its means, there remains no other electricity to be accounted for or to be referred to any action other than that of the zinc and the water on each other. 927. The general case (for it includes the former one (924. )>) of acids and bases, may theoretically be stated in the following manner. Let fl, fig. 7. be supposed to be a dry oxyacid, and b a dry base, in contact at c, and in electric com- munication at their extremities by plates of platinapjo, and a platina wire w. If this acid and base were fluid, and com- bination took place at c^ with an affinity ever so vigorous, and capable of originating an electric current, the current could not circulate in any serious degree ; because, according to the experimental results, neither a nor b could conduct without being decomposed, for they are either electrolytes or else in- sulators, under all circumstances, except to very feeble and unimportant currents (970. 986.). Now the affinities at c are not such as tend to cause the elements either of a or b to separate, but only such as would make the two bodies com- bine together as a whole ; the point of action is, therefore, in- sulated, the action itself local (921. 947.), and no current can be formed. 928. If the acid and base be dissolved in water, then it is possible that a small portion of the electricity due to chemical action may be conducted by the water without decomposition (966. 984.); but the quantity will be so small as to be utterly disproportionate to that due to the equivalents of chemical force; will be merely incidental ; and, as it does not involve * It will be seen that I here agree with Sir Humphry Davy, who has ex- perimentally supported the opinion that acids and alkalies in combining do not produce any current of electricity. Philosophical Transactions 1826, p. 398. [or Phil. Mag. and Annals, N.S. vol. i. p. 98.— Edit.] Combinatioji "with the ^Icidj^yoduces no Electricity, 131 the essential principles of the voltaic pile, it forms no part of the phaenoniena at present under investigation*. 929. If for the oxyacid a hydracid be substituted (927. )> — as one analogous to the muriatic, for instance, — then the state of things changes altogether, and a current due to the chemical action of the acid on the base is possible. But now both the bodies act as electrolytes, for it is only one principle of each which combine mutually, — as, for instance, the chlo- rine with the metal, — and the hydrogen of the acid and the oxygen of the base are ready to traverse with the chlorine of the acid and the metal of the base in conformity with the cur- rent and according to the general principles already so fully laid down. 930. This view of the oxidation of the metal, or other di- 7'ect chemical action upon it, being the sole cause of the pro- duction of the electric current in the ordinary voltaic pile, is supported by the effects which take place when alkaline or sulphuretted solutions (931. 94-3.) are used for the electrolytic conductor instead of dilute sulphuric acid. It was in elucida- tion of this point that the experiments without metallic con- tact, and with solution of alkali as the exciting fluid, already referred to (884.), were made. 931. Advantage was then taken of the more favourable con- dition offered, when metallic contact is allowed (895.), and the experiments upon the decomposition of bodies by a single pair of plates (899.) were repeated, solution of caustic potassa being employed in the vessel t;, fig. 5. in place of dilute sul- phuric acid. All the effects occurred as before: the galva- nometer was deflected; the decompositions of the solutions of iodide of potassium, nitrate of silver, muriatic acid, and sul- phate of soda ensued at x\ and the places where the evolved principles appeared, as well as the deflection of the galvano- meter, indicated a current in the same direction as when acid was in the vessel v\ i. e. from the zinc through the solution to the platina, and back by the galvanometer and decomposing agent to the zinc. 932. The similarity in the action of either dilute sulphuric acid or potassa goes indeed far beyond this, even to the proof of identity in quantity as well as in direction of the electricity produced. If a plate of amalgamated zinc be put into a solu- tion of potassa, it is not sensibly acted upon ; but if touched * It will, I trust, be fully understood, that in these investigations I am not professing to take an account of every small, incidental, or barely pos- sible effect, dependent upon slight disturbances of the electric fluid during chemical action, but am seeking to distinguish and identify those actions on which the power of the voltaic battery essentially depends. S2 1 32 Dr. Faraday's Experimental Researches in 'Electricity, in the solution by a plate of platina, hydrogen is evolved on the surface of the latter metal, and the zinc is oxidized exactly as when immersed in dilute sulphuric acid (863.). I accord- ingly repeated the experiment before described with weighed plates of zinc (864^. &c.), using however solution of potassa instead of dilute sulphuric acid. Although the time required was much longer than when acid was used, amounting to three hours for the oxidizement of 7*55 grains of zinc, still I found that the hydrogen evolved at the platina plate was the equiva- lent of the metal oxidized at the surface of the zinc. Hence the whole of the reasoning which was applicable in the former instance applies also here, the current being in the same di- rection, and its decomposing effect in the same degree, as if acid instead of alkali had been used (8^38.). 933. The proof, therefore, appears to me complete, that the combination of the acid with the oxide, in the former ex- periment, had nothing to do with the production of the elec- tric current; for the same current is here produced when the action of the acid is absent, and the reverse action of an alkali is present. I think it cannot be supposed for a moment, that the alkali acted chemically as an acid to the oxide formed ; on the contrary, our general chemical knowledge leads to the conclusion, that the ordinary metallic oxides act rather as acids to the alkalies : yet that kind of action would tend to give a reverse current in the present case, if any were due to the union of the oxide of the exciting metal with the body which combines with it. But instead of any variation of this sort, the direction of the electricity was constant, and its quan- tity also directly proportional to the water decomposed, or the zinc oxidized. There are reasons for believing that acids and alkalies, when in contact with metals upon which they cannot act directly, still have a power of influencing their attractions for oxygen (941.); but all the effects in these experiments prove, 1 think, that it is the oxidation of the metal necessarily dependent upon, and associated as it is with, the electrolyza- tion of the water (921. 923.), that produces the current; and that the acid or alkali merely act as solvents, and by removing the oxidized zinc, allow other portions to decompose fresh water, and so continue the evolution or determination of the current. 934. The experiments were then varied by using solution of ammonia instead of solution of potassa; and as it, when pure, is a bad conductor, like water {^^b^.), it was occasion- ally improved in that power by adding sulphate of ammonia to it. But in all the cases the effects were the same as before; decompositions of the same kind were effected? and the electric Sir David Brewster's ^o//V^ of a new Mineral. 133 current producing these was in the same direction as in the experiments just described. [To be continued.] XXI. Notice of the Optical Properties of a new Mineral sup- posed to be a Variety of Cymophane. By Sir David Brew- ster, K.H., F.R.S. TT AVING just received from my friend Mr. Nils Norden^ ^ -■■ skiold of Helsingfors, a specimen of a new mineral having interesting optical properties, I hasten to communicate a brief notice of these to the readers of this Journal. Mr. Nordenskiold received specimens of this mineral last spring from His Excellency Sir L. PerofFsky of St. Peters- burgh. It was found in the Emerald mines near Caterinen- burg in Siberia ; and it occurs in large crystals from one to two inches in diameter, which are generally composed in the same manner as is shown in fig. 38, plate vii., of the second volume of Mohs's Mineralogy. Mr. Hartwall is at present engaged in analysing the mineral, the result of which we shall communi- cate as soon as it reaches us. Mr. Nordenskiold, however, has ascertained that its colouring matter depends on a small admixture oi oxide of chromium. When this mineral is seen in daylight it is of a bright green colour, whereas by candlelight its colour is a pink red. Mr. Nordenskiold has likewise observed, that when a compound crystal is examined with a piece of tourmaline, or in polarized light, one portion of it is of an emerald green colour, while another is oio. faint dirty yellow colour; and that when the cry- stal is turned round 60°, the part which was yellow becomes eme- rald green, and vice versa. Mr. Nordenskiold adds that the mineral seems to be more transparent in candle- than in day- light. Having repeated these experiments I have found them in every respect perfectly correct ; the yellow colour, however, which is described as dirty, loses this character when the spe- cimen is placed in a fluid, and it then appears to be intermixed with red, so as to show that if the thickness of the specimen were successively increased, the colour would be redder and redder, and terminate in a bright red tint. Although Mr. Nordenskiold has mentioned that the com- pound crystals resemble the starlike compound crystals of car- bonate of lead figured by Mr.Haidinger in his edition of Mohs's MineralogVj yet, from the optical phaenoniena, we are disposed to regard the compound as consisting of three single crystals united at angles of 60°, for if the united crystals were each compound, the colours would change at every 30° of revolution. 1 34? Prof. Forbes on the Refraction aiid Polarization of Heat. The change of colour which is exhibited by looking through the mineral in day- and in candle-W^^t^ arises from two causes : 1st, from there being an excess o^red and a defect of blue rays in the light of a candle compared with the light of day ; and 2ndly, from the substance employed having a greater dispo- sition to transmit one kind of rays in preference to another, or, what is the same thing, being more transparent for one kind of rays than for another kind, v/hen their intensity is the same. In the present mineral its colour \s green ; but when we ana- lyse it with the prism we find that the green is a compound co- lour consisting of red and green, the green predominating greatly in dai/Vight : but in ca?idle\\g\it the colour is a piiik red, because the greater quantity of red in this light and the smaller quantity of blue and greeii, gives the red colour a de- cided predominance over the green, so as to make the com- pound colour pink red. There are several crystals, natural and artificial, and various solutions in which this change of colour is beautifully seen. It is particularly visible in the green ]mces of plants, which are green in daylight, and of a blood red colour in the light of a candle. In the mineral under our consideration Mr. Nordenskiold found traces of the oxide of chromium, to which he attributes its colour. That this is the colouring matter, and that the ac- tion of this metal is the cause of its peculiar property in refer- ence to light, may be inferred from the fact that the very same property is possessed by the triple oxalate of chromium and potash, and also by the sulphate of ammonia and chromium, whether these salts are used in the solid state or in a state of solution. XXII. On the Refraction and Polarization of Heat. By James D. Forbes, Esq., F.R.SS. L. Sf E., Professor of Na- tural Philosophy in the University of Edinburgh.* § 1 . Some Miscella?ieous Experiments with the Thermo- Multiplier. § 2. On the Polarization of Heat by Tourmaline. § 3. On the Polarization of Heat by Refraction and Reflection. § 4. On the Depolariza- tion and Double Refraction of Heat. 1. npHE experiments to be detailed in this paper, which -*■ chiefly go to establish properties of heat wholly un- looked for, or only suspected to exist, having been made en- * Communicated by the Author; having been read before the Royal Society of Edinburgh on the 5th and 19th of January 1835. Prof. Forbes on the Refraction and Polarization of Heat. 135 tirely by means of an instrument of great delicacy— the thermo-multiplier of MM. Nobili and Melloni, — I shall pre- mise some account of its application to the investigation of some more familiar modes of action. § 1. Miscellaneous Experiments. 2. We could hardly quote a stronger proof of the rapid and unexpected advances which enlarged theory may produce in practice, than by referring to the employment of thermo- electric action, discovered a few years since by Seebeck, to the measurement of heat, with a degree of accuracy and fa- cility which, perhaps, no thermometer has ever attained. Such is the principle of the thermo-multiplier of Nobili and Melloni. It is well known, that when two metals (and espe- cially bismuth and antimony) are soldered together, and the point of union heated, an electric current is established from the one metal to the other, which may be carried off by wires, and caused to act upon a delicate galvanometer or multiplier, the needle of which serves as an index ; the galvanometer consisting, of course, of a magnetic needle, nearly freed from the influence of the earth's magnetism, and so conrlected with the wire which transmits the electricity, that the mutual in- fluence of the magnetism and the electricity shall (by the law of CErsted) be a maximum. 3. It will readily be conceived, that, if a series of alternat- ing bars of bismuth and antimony be placed parallel to each other, and the extremities alternately soldered together, when all the extremities facing one way are heated (as by the radi- ant influence of a lamp), whilst the others remain at the tem- perature of the apartment, the effects produced in a single pair, such as we first supposed, will be produced at each junc- tion, and that the intensity of the whole effect will be greater, just as in the voltaic pile. At one time it appeared doubtful how far electricity, of such small tension as is thus produced, could be so reinforced ; but the instrument in question seems to prove the practicability of it. About thirty pairs are em- ployed, and so delicately are they made, that the ends which exhibit one set of junctions are contained within a superficial area of four tenths of an inch square. 4. The wires, from the extremity of the first and last ele- ment (just as in the voltaic battery), convey the electricity to the multiplier, which consists of a flattened coil of silver-wire, covered with silk, the coils of the wire being parallel to the quiescent position of an astatic magnetic needle, which is per- pendicular to the magnetic meridian. The deviations are measured in the usual manner, on a divided circle; upon 1 36 Prof. Forbes ofi the Refractiori and Polarization of Heat. which, with practice, ^th of a degree may always be observed, and even minuter quantities occasionally estimated. These divisions are not necessarily proportional to the intensities of the currents which produce the corresponding deviations. The coils of wire, extending a long way on each side of zero, prevent the effect from diminishing so rapidly as if they were concentrated there; and M. Melloni has described, in his paper in the Annates de Chimie for May 1833, a simple and satisfactory method of estimating the relative values of de- grees, at different points of the scale. He states, however, that, under 20° of deviation, he found them quite uniform. In the following experiments, the deviations were generally under 15°, and in almost no case exceeded 20°. I have there- fore assumed the forces to be as the deviations. Besides, no change of importance would take place from a deviation from this law by a small quantity. 5. It will be perceived in the experiments which are to be detailed, that the determination of all the more important facts depend generally on whether one effect be greater or less than another, without much regard to their absolute amount. Now, the confidence which we can place in the uniformity of this instrument, or at least of the small changes capable of affecting it (since it is not liable like thermometers, and espe- cially air-thermometers, to advance by starts,) is such, as to admit of almost indefinite subdivision, where the relations of small quantities are alone concerned. I conceived, therefore, that without impairing its sensibility by lengthening the gal- vanometer needle, we might advantageously magnify the divi- sions by optical means. This I proposed to do by observing the motions of the index by means of a small telescope, fixing in front of the object glass a lens whose focus is situated at the part of the scale desired to be magnified. It might also be easy, in order to compare larger quantities, to make this mi- crometrical system revolve so as to be always similarly placed as regards the needle, and thus avoid the effects of parallax, which at present require constant vigilance. 6. The method here indicated, I have put into practice with the greatest success in my later researches ; one tenth of a degree becomes easily visible, and the constancy of the in- dications fully justifies this method of microscopic examination, which has enabled me to verify the most delicate deductions I had drawn from simple observation, and to obtain results which otherwise I must have been unable confidently to announce. 7. For the precautions to be employed in the use of the thermo-multiplier, I must refer to the first of M. Melloni's very original papers in the Annates de Chimie (for May 1833), Prof. Forbes on the Refraction a?td Polarization of Heat. 157 but I may state, once for all, that when once habituated to the use of it, I have found it more simple, manageable, and comparable, than I could previously have imagined. Not- withstanding its delicacy and the promptitude of its action, a few precautions suffice to prevent any derangement from with- out. The only inconvenience which I experienced, was in the determination of the zero of the scale, which appears lia- ble to some fluctuations, which may be considered as acci- dental. It rarely happened, however, that these affected the results of my experiments, because, as I have said, these were always confined to small variations of temperature (indicated by a deviation generally under 15° on the scale) when such fluctuations did not appear; and the results produced by the same cause under the same circumstances were admirably constant, as well as the position of the zero point. 8. There is one circumstance which gives a degree of deli- cacy to the indications of the thermo-multiplier, when we wish to ascertain very minute differences of effect, which no other thermometric instrument possesses. When we wish to ascer- tain the existence, not the measure, of some cause of heat or cold, if we watch the needle of the multiplier at the instant at which the change of circumstances intended to produce the effect takes place, we shall perceive, in the instantaneous effect on the needle, an evidence of a far more decisive character than the merely statical deviation (at which, after several oscil- lations, it is finally to settle) could afford. Not only does the acquired velocity carry it through double the space due to the statical effect; but I have observed that the action of the thermo-electric pile so far resembles that of the voltaic, that we appear to have an excess of effect at the first moment of action, which gives a greater deviation than can be afterwards obtained*. It is therefore to be recollected, that, in speaking confidently of effects, which, statically speaking, are exceed- ingly small, the experimentalist has a species of evidence far stronger than the mere numerical expression of the deviation of the needle, but the degree of which must be taken on the • This remarkable effect, which may be described as an increase of ten- sion by confinement, seems generally to exist where the conductors of im- ponderable agents oppose considerable resistance to their passage. It is fa- miliar in voltaic electricity, and I have often observed it in magnetic elec- tricity. It is similar to the action which I have attempted to demonstrate in the passage of heat from good to bad conductors (see Lond. and Edinb. Phil. Mag., vol. iv., p. \b^etseq.)y where we have the full advantage of the dynamical effect ; whilst the existence of statical tension in heat seems like- wise to be proved (as we might have anticipated) by the beautiful experi- ment described by Professor Powell in the Philosophical Transactions for 1834, and noticed in the last number of this Journal, p. 58, Third Series, Vol. 6. No. [)2, Feb, 1835. T 1 38 Prof. Forbes on the Refraction and Polarization of Heat, faith of his veracity. Thus I have obtained repeated differ- ences, not exceeding half or even a quarter of a degree of the multiplier (observed without a telescope), which, by the promp- titude with which the needle was repelled or attracted at the instant that the change of circumstances to be considered was effected, left as little doubt in my mind as if the numerical result had been many times greater. 9. Having satisfied myself^ in a variety of ways, of the ex- treme delicacy and promptitude of action of this instrument, I thought of applying it to detect the heat of the moon's rays in a more unexceptionable manner than, I am persuaded, it has ever been attempted. This curious question had not escaped MM. Nobili and Melloni when they first constructed the in- strument, and they mention in their first account of the ther- mo-multiplier their attempts at its solution*. But, like pre- vious experimenters, they employed a metallic mirror to con- centrate the rays of the moon, which, acting in the usual man- ner of dispersing the heat of the thermometer, produced sogreat a cooling effect, as completely to neutralize any positive results. 10. It occurred to me, however, from the consideration of M. Melloni's very decisive experiments as to the permeability of screens of different kinds to heat from various sources, that the moon's heat must, in very great proportion at least, ra- diate through glass. And this on several grounds ; as, 1. be- cause the sun's heat, of which this may be considered as an integral part, does so with scarcely any loss ; 2. because heat, accompanied by light, always does so, and generally in pro- portion to the brilliancy and refrangibility of that light; and, 3. because the lunar rays having passed through the whole thickness of the atmosphere must, according to the experi- ments of De la Roche, fully confirmed by Melloni, have parted with the greater part of that species of heat most easily stop- ped, and hence arrive at the earth in a state comparatively capable of passing through glass and similar substances. If this opinion be correct (nor can I entertain any doubt upon it), if we substitute a lens for a mirror to concentrate the lunar rays, we shall profit by all, or nearly all, of their heating ef- fect, whilst such a lens, instead of promoting the radiation of the heat of the thermometer to the sky, will entirely stop it (because heat of this description does not pass sensibly through the thinnest glass), and thus its disturbing influence will be entirely prevented. 11. I employed, therefore, a polyzonal lens made by Soleil of Paris, in my custody, to concentrate the moon's light. The diameter of the lens is 30 inches ; its focal distance about -il • Anna/es de Chimie et de Physique, December 1831. Prof) Forbes 07i the Refraction and Polarization of Heat. 139 inches, whence we may compute the size of the lunar image to be a circle 0*38 inch in diameter. Comparing this with the dimensions of the intercepted cylinder of rays, we shall find the concentration to exceed 6000 times. But even if we admit that half the rays are reflected, dispersed and absorbed, we shall have still an effective increase of 5iOOO times. 12. My experiments were made on the 16th December 1834, between 9 and 11 o'clock, the moon being only 18 hours past full, and (towards the close) less than 2 hours from the meridian. She was also particularly high, having a declina- tion of 25° north. The thermal pile, which was particularly commodious for the experiment, had one extremity elevated to the proper angle, and being placed accurately in the focus of the mirror, the moon's image was brilliantly thrown on the extremity of the pile. The sky was on the whole very pure, though an occasional milkiness was perceived, but the best observations were made at the clearest moments, because then the air was also most still ; for though the instrument was placed in a most sheltered spot, the faintest breeze was indi- cated by a deflection of the needle, and with such promptitude, that I generally could perceive in this way its approach before I could feel it. The action of the lens was so perfect, that the image was perfectly sharp, and the spots clearly defined. The lunar rays were alternately screened and admitted by an as- sistant passing a sheet of pasteboard across the surface of the lens next the moon -, for when it was interposed between the lens and the instrument, a sensible disturbance took place. By these and other precautions, the needle was steady beyond my expectations, and during an hour and a quarter that the ob- servation lasted, I had probably at least twenty perfectly unex- ceptionable comparative observations, free from the influence of wind, and which invariably gave not the faintest indication of warmth. When I got a deviation of the needle at the mo- ment of unscreening the moon's rays, I verified it by screen- ing them instantly, and watching for a return to zero, but I was always disappointed. I feel quite confident that the effect, if there was any, could not amount to a quarter of a degree of the galvanometer ; and, owing to the dynamical effect which I have described of a first impulse, that it is improbable that it amounted to half that quantity. 13. Hence it becomes an object of interest to form some estimate of the sensibility of the thermo-multiplier, compared to common thermometers. It would be difficult to give a pre- cise measure of the degrees of temperature of the two extre- mities of the pile*, but we may compare the effect of equal * This might best be done by adapting a differential thermometer of ex- treme delicacy, so that the balls might be in contact with the two extre- T2 1 40 Prof. Forbes on the Refraction and Polarization of Heat. quantities of heat upon this and another instrument. For this purpose I employed two air thermometers of great delicacy ; one was the photometer of Leslie, having one ball covered with lamp black, and exposed to the same source of heat as the pile, whilst the other ball was shaded. The other instru- ment was a vertical differential thermometer, having a hemi- spherical reflector, intercepting a cone of rays 2' 50 square inches in section. I found it impossible to operate with small degrees of heat, which could not be reckoned accurately on the air thermometers, owing to their tardy action ; but, from several experiments, I concluded that the same quantity of heat falling on the photometer ball and on the pile, moved the liquid of the former through ] °, and the needle of the multiplier through 4'^*2. The degrees of the photometer being lOths of 1° cent., one centigrade degree would corre- spond to 42° of the galvanometer (assumed of equal value throughout the scale). The experiment with the differential thermometer, being similarly conducted, gave for the effects of equal quantities of heat, 1° cent, to 62° of the multiplier. If we assume from these experiments that a quantity of heat which raises an air thermometer by one fiftieth of a centigrade degree, affects the galvanometer by 1°, since a quarter of a, degree of the latter is a measurable quantity, and half of that may be estimated as a sensible impression, we may measure an effect of ^^o ^^ ^ centigrade degree, and perceive (by un- assisted vision), an effect of ^^q. 1 4. In the case of the moon's rays, concentrated 3000 times, we have seen that it is improbable that even the last effect was produced. The whole sensitive extremity of the pile being larger than the moon's image, was not brought into action ; but if we compare their relative dimensions*, we shall still find that it is improbable that the direct light of the moon would raise a thermometer one three-hundred-thousandth part of a centigrade degree^ at least in this climate. 15. The value of the thermo-multiplier consists not so much in the minuteness of its indications, which may easily be equalled by employing large enough thermometers, but in the certainty and rapidity of its action. Air thermometers, such as I compared it with, though the size of the balls was inconsi- derable, required so long a time to assume their temperature, mitie? of the pile, and the spaces round them filled up with copper filings, or some such material. But the experiment could hardly be quite decisive. * The moon's image contained 0*114 square inches, whilst the area of the pile is about 0*40. Hence little more than a fourth of the pile was brought fully into action ; but any dispersed light (for which we have made allowance), would act on the neighbouring parts. Prof. Forbes on the Refraction and Polarization of Heat, 141 that, when exposed simultaneously with the thermal pile to the source of heat, the latter had almost assumed its maximum ef- fect before the others had sensibly moved ; and it is obvious that, in delicate experiments, where constancy in the produ- cing cause is presumed, rapidity of execution is essential. In short, with an air thermometer (which requires from 10 to 15 minutes to give a single result), the greater part of the expe- riments to be described would have been impossible from this cause alone, and the remainder would have been tedious be- yond measure. It will therefore be conceived that were ther- mometers enlarged so as to give as minute indications as the multiplier, they would be utterly unmanageable. 16. Of all the researches of M. Melloni on radiant heat that of the refrangibility of non-luminous heat by a prism of rock salt is the most striking. Viewing it in connexion with the theory of heat, and its analogies with light, this experiment is even more important than those connected with the very obscure subject of absorption, which has been illustrated by his numerous determinations of the stoppage of radiant heat, by screens or media of different kinds. At the time when I commenced these experiments, in November last, I was not aware that M. Melloni had published a second memoir, which, after many of my experiments were made, I met with in the fifty-fifth volume of the Annales de Chimie. It appeared to me a matter of great interest to determine the refrangibility of non-luminous heat by direct experiment ; and, in doing this, I was led to verify, in the fullest manner, the published expe- riments of M. Melloni on the refraction of heat, not merely de- rived from brass heated by an alcohol lamp, so as not to have the faintest luminosity in the dark, but also of heat derived simply from water under its boiling point. I found that so admirable was the sensibility of the instrument, that we may determine, with great accuracy, by repeated trials, the angular position of ihe prism which gives the maximum effect; and, having given the angles made by the incident and emergent rays with the sides of the prism under those circumstances, we may compute the index of refraction for the rock-salt, in regard to rays of heat. Upon making the calculation, it ap- peared that the direction thus experimentally found, gave nearly the same result as for light, which was an ample proof of the reality and striking nature of the experimental result ; but it at the same time appeared that the whole dispersion for the spectrum is so inconsiderable, that, in this way, we could hardly expect to obtain a numerical result for the dispersion of the heating rays. I afterwards found, upon reading M. Melloni's second memoir, that he had experienced the same difiiculties, and that, though he constructed a pile on purpose, 1 '1-2 Royal Societj/. he had not succeeded in obtaining numerical results. He found, however, that the refrangibility of the rays diminished with their temperature. 1 also obtained a slight refraction of non-luminous heat through a glass prism. 1 7. But if heat be capable of refraction by the ordinary agents, an important question arises, Is the phajnomenon of double refraction common to heat and light? Rock-salt, the only substance yet discovered vi'hich transmits dark heat in large quantity, does not possess this power. To attempt it with Iceland spar would certainly be fruitless, from the very small transmitting power which it possesses, besides some other practical difficulties which suggest themselves. It must be by more refined processes that we can detect this property. Such will be stated in the sequel. [To be continued.] XXIII. Proceedings of Learned Societies. ROYAL SOCIETY. 1834. A PAPER was read, entitled, " On the Determination A Nov. 20. — -^^ of the Terms in the disturbing Function of the fourth Order, as regards the Eccentricities and Inclinations which give rise to secular inequalities." By J. W. Lubbock, Esq., V.P. and Treas. R.S. The author observes, that the magnitude of the terms of the fourth order in the disturbing function, relating to the inclinations, in the theory of the secular inequalities of the planets, does not admit of being estimated d, priori ; and consequently the amount of error which may arise from neglecting them cannot be appreciated. The object of the present investigation is to ascertain the analytical ex- pressions of these terms ; and the method adopted for this purpose is derived from principles already explained by the author in a for- mer paper. He has bestowed great pains in putting these expres- sions into the simplest form of which they are susceptible ; and has finally succeeded, after much labour of reduction, in obtaining ex- pressions of remarkable simplicity. He exemplifies their application by the calculation, on this method, of one of the terms given by Pro- fessor Airy as requisite for the determination of the inequality of Venus ; and arrives, by this shorter process, at the same result. The same method, he remarks, is, with certain modifications, applicable to the development of the disturbing function in terms of the true longitude. A paper was also read, entitled " Note on the Astronomical Re- fractions." By James Ivory, Esq., K.H., M.A., F.R.S. The object of this communication is to show how far the author has been successful in establishing the true theory of astronomical refractions, in his paper published in the Philosophical Transactions for 1823, by comparing the results of that theory with the best and most recent observations ; namely, those recorded in the " Funda- Royal Society, 1 43 menta Astronomise" of Bessel, and the " Tabulae Regiomontanae" of the same author. This comparison is made by taking the first and second differences of the series of the logarithms of the refrac- tions in each table ; from which it results that these differences, de- rived from the numbers in Bessel's tables, are very irregular ; but that their mean very nearly coincides with that of the numbers given in the tables of the author. November 27. — A paper was read, entitled, " Meteorological Journal kept at the Royal Observatory, Cape of Good Hope, from the 1 St of February to the 3 1 st of May, 1 834 ." By Thomas Maclear, Esq. Communicated by Captain Beaufort, R.N., F.R.S. The tables of meteorological observations which compose nearly the whole of this paper are preceded by a short notice of the instru- ments, namely, one barometer and two thermometers, with which the observations were made. The author announces his intention to forward, in a future communication, the results of a comparison be- tween his barometer and that of Sir John Herschel. The obser- vations are taken at sunrise, at noon, at sunset, and at midnight. The reading of a paper was commenced, entitled, " On the Proofs of a gradual Rising of the Land in certain parts of Sweden." By Charles LyeU, Esq., F.R.S. At the Anniversary Meeting, December 1, 1834, which was held on that day in consequence of St. Andrew's Day falling on a Sunday, John William Lubbock, Esq., M.A., V.P. and Treasurer, in the Chair, the Treasurer stated that he took the Chair on the present occa- sion in consequence of the unavoidable absence of His Royal Highness the President ; from whom he had received the following letter : " Dear Sir, " May I request of you to express to the gentlemen as- sembled this day at the Royal Society Rooms, my extreme regret that the state of my eyesight should prevent my attending in my place on the present occasion, as it would otherwise have been botli my duty and pleasure to have done ? Under these circumstances I must rely upon that kindness which I have ever experienced at their hands since presiding over the interests of the Royal Society, to ex- cuse this involuntary absence on my part. Should the gentlemen kindly vote me again into the Chair, aware as they are of my present infirmities, I can only accept the proffered honour upon an under- standing that should I not be better at this period next year, I may be now considered as giving them notice that I shall consider myself bound in duty to resign an office, the duty of which I am no longer able to perform. I regret much being deprived of the pleasure of conferring the medals this day, and particularly the one which has been so properly adjudged to you, for whom I profess the highest consideration, and with which sentiment I subscribe myself, " Very sincerely, yours, &c., (Signed) " Augustus Frederick, P.R.S. " Kensington Palace, Dec. 1, 1834. " John William Lubbock, Esq., Treasurer of the Royal Society." Resolved unanimously, — That this Meeting deeply regrets the aiflic- li^ Royal Society, tion which deprives the Society of His Royal Highness's attendance at the Anniversary Meeting, and confidently hope that his health will be speedily and completely restored. The Secretary read the following List of Fellows deceased since the last Anniversary. On the Home List. — Sir Gilbert Blane, Bart., M.D. ; John, Mar- quis of Breadalbane ; John Caley, Esq. ; Rev. James Stanier Clarke, LL.D. ; Captain James Franklin ; William Wyndham, Lord Gren- ville; Philip, Earl of Hardwicke ; George Harvey, Esq. ; John Jebb, Lord Bishop of Limerick; Rev. Daniel Lysons ; William Taylor Mo- ney, Esq. ; John Sharpe, Esq. ; Thomas Snodgrass, Esq. ; William Sotheby, Esq. ; George John, Earl Spencer ; Thomas Telford, Esq. ; Right Hon. Charles Philip Yorke. On the Foreign List. — Don Felipe Bauzk and Professor Karl Lud- wig Harding. Tlie Secretary stated that of these only two, namely. Sir Gilbert Blane and Mr. George Harvey, have contributed papers to the Royal Society. Sir Gilbert Blane was the author of a paper, entitled, " An Ac- count of the Nardus Indica, or Spikenard," which was published in the Philosophical Transactions for 1790. In this paper. Sir Gilbert, then Dr. Blane, establishes the identity of a species of grass, found in great abundance in a wild unfre- quented part of India at the foot of the mountains north of Lucknow, and held in great estimation by the natives as a febrifuge, with the plant denominated by ancient writers the Nardus Indica, and which Arrian states was found in great quantity by the armies of Alex- ander during their marches through the deserts of Gadrosia, border- ing on the Persian Gulf, and forming part of the modern province of Mekran. An account of the medicinal properties of this plant occupies the remainder of this paper. In the year 1788, Sir Gilbert Blane was appointed to read the Croonian Lecture, in which he enters into a general account of the nature of the muscles and of the theory of muscular motion. This paper was not published in the Philosophical Transactions. The portion of it chiefly deserving notice is that which relates to the ex- periments made by him with a view to determine whether the spe- cific gravity of a muscle is the same in its two states of relaxation and contraction. For this purpose he compared equal portions of the muscular flesh taken from the opposite sides of a fish, one of which had been contracted by crimping, and the other had remained relaxed ; but he was unable to detect any sensible difference in their specific gravities. This conclusion was corroborated by the result of experiments on living eels, inclosed in vessels filled with water, and terminating above in a tube of small diameter : the bulk of the fluid was observed to be unaff^ected by muscular contractions pur- posely excited in the fish, as appeared from the height of the column in the tube remaining unchanged during the most violent actions of the eels. In caoutchouc, on the other hand. Sir G. Blane found that extension produced a diminution, and retraction an increase, of density. Royal Society. 1 45 Mr. George Harvey was the author of a paper entitled " Expe- rimental Inquiries relative to the Distribution and Changes of the Magnetic Intensity in Ships of War;" and of another " On the Effects of the Density of Air on the Rates of Chronometers ;" both of which are published in the Philosophical Transactions for 1824. In the first paper he enters into a detail of experiments made on board several vessels for the purpose of determining the influence of the iron in the ships upon the mariner's compass in different situa- tions and under different circumstances. In the second paper he as- certains that the rate of chronometers is accelerated by being placed in air of diminished density; and that it was, on the contrary, retarded when they are subjected to increased atmospheric pressure ; the arc of vibration being, in the former case, increased ; and in the latter, diminished. The Secretary then read the Reporv of the Council, from which the following are extracts ; the Report being given entire in the " Proceedings" of the Society. On the subject of the Library the Council have, in the first place, to report that the manuscript of the classed Catalogue is now very nearly completed, and that the printing of it will be very soon com- menced. The Council beg, in the second place, to congratulate the Society on their having, after so much delay, at length obtained possession of the apartments lately occupied as the Exchequer Office, and granted by the Lords Commissioners of His Majesty's Treasury, on the re- presentation made to them by His Royal Highness our President, to the Ro3"al, conjointly with the Astronomical, Society. The apart- ments retained by the Royal Society are four in number : the first is a room adjoining to the upper library, from which a door has been opened into it, and which has been fitted np with shelves for the re- ception of the books formerly kept in the rooms on the basement floor of the next house, under the rooms of the Geological Society. The second is a smaller room, communicating by a door with the Council-room. The third is also a small room, opening into the ante- room, on the same floor. The fourth room is situated on alower floor. It having been determined at a former Council, in November of last year, that application should be made to the Lords of the Ad- miralty to direct the observations made at various stations by their order, to be printed at the public expense ; Their Lordships have gra- ciously acceded to this request. The Council, having been applied to by the Commissioners of Ex- cise to undertake the investigation of the proper instruments, and the construction of tables, for ascertaining the strength of spirits, with a view to the more accurate charging of the duty thereon, have appointed a Committee for conducting the proposed inquiry, and ful- filling the objects of the requisition. ITie Copley Medal has been awarded by the Council to Professor Plana for his work, entitled " Theorie du Mouvement de laLune." The two Royal Medals for the present year have been awarded, the one, on Physics, to John William Lubbock, Esq. ; and the other. Third Series, Vol. 6. No. 32. Feb. 1835. U 146 Geological Society, on Mineralogy ::::::9:r:::::::99::::::::::::'o o 6 •puo-i §::: :Sr rS' :::::: :^ ::::::::: : :S^;^ ^t 6 o C isog ^•^•ssE.s^-s^sssssssssas.^.ssss.ss •puoq 1^ •KVfg nsog odbtooot^voc«F-coasiri ^ tO' ^f s • cochin o 00 r-c^cocDoo 00 c«c» voo 00 o^— o GO ^o r^tn o iO-< o ^*o^o cT) m .5 •«!ttO-OI -^"^ coco 0« C» O coco "^ CO coo ■^OOOI + -3312) ex i^^±^ : : -267 : ^ ; so that x'^ or the specific heat of air at temperature /' and 4,40 I /^ so pressure 'p = -~~^ x '-— x ('0223 /? + -3312) x '267. The value, therefore, of y^' already given, when corrected for the influence of pressure on specific heat, will become f— -—x ^ X {'022S p -h '3312); an expression which is obviously, as it ought, reduced to f— — when t' = 60°, and p = 30. The theoretical justness of the fourth objection must also be conceded. The medium which is in contact with the bulb of the hygrometer is not dry air, but air charged with the amount of vapour which belongs to the existing dew-point ; and, as the specific heats of air and vapour are different, this mixed atmosphere in cooling through t—t' degrees will evi- dently not give out the same quantity of caloric, and can therefore not convert into vapour the same quantity of water that would be evolved and vaporized by the same weight of dry air alone. In fact, for -267 the specific heat of air, we should in strictness substitute the specific heat of the mixture of air and vapour; or, what will answer the same purpose, Third Series. Vol. 6. No. 33. March 1835. 2 B 186 Dr. Apjobn*s Formula for inferring the Dew-point multiply by the ratio of these the subtractive terms in the value ofy" aheady obtained. To determine the specific heat of a mixture, the simple rule is to multiply the relative weights of its constituents by their respective capacities, and to divide the sum of the pro- ducts by the sum of the weights. But in the present instance the weights, being obviously as the specific gravities, are to each other as 1 : -625 •^^. Also the specific heat of air being •267, and that of vapour '847, the former is to the latter as 1 : 3*172. Hence, according to the rule given above, we shall l+-625-^" X 3-172. , .^ ^ P u • nave J= tor the specific heat of the mixture fn * H--625^^— P of air and vapour referred to that of dry air taken as unity ; and, applying the correction as already explained, we shall have an equation in which y" is the only unknown quantity, and from which, therefore, its value may be found. This equation, however, being a quadratic, and the unknown quan- tity in its first elimination having a coefficient of three terms, its solution would involve tedious arithmetical operations, and cannot, therefore, be recommended to the practical me- teorologist as a means of making the correction in question. Nor is this course at all necessary ; for the same object may be achieved, according to a simpler, though less rigorous method, by either assigning to^" an average value, or by de- ducing approximately the tension of vapour at the dew-point by the formula /" =/' - ^x ^^'x(-0223;> + -3312), and using the value ofy" thus obtained, in order to deter- H- -625— X 3-172 mine that of — ^ , the specific heat of the mix- l+-625^ ture of air and vapour. The latter method is decidedly the best, and though not mathematically accurate, will not, I be- lieve, exhibit a deviation from the truth until the calculation be pushed to the seventh or eighth decimal place. I have now to notice the last circumstance which, as far as I understand the subject, can have any influence upon the accuracy of my determination of the dew-point. When the wet-bulb hygrometer has attained its stationary from the Indications of the Wet-bulb Hygrometer. 187 temperature, the quantities of caloric which it loses and gains in a given time are perfectly equal. This requires no demonstra- tion. The caloric lost also is entirely employed in converting the water into vapour; but the whole of the acquired caloric is not necessarily derived, though this is assumed to be the case, from the air cooled by contact with the bulb of the instru- ment. In fact, the hygrometer is in the predicament of a cool body placed in a warm medium, and it must consequent- ly receive from surrounding bodies by radiation a greater amount of caloric than it imparts to them in virtue of the same process. To the d grains, therefore, of moisture con- verted into vapour by the heat given out by 4195 grains of air in cooling through d degrees, we should add the addi- tional quantity vaporized by the heat which the bulb has in the same time received by radiation. Where t—t^ is small, this quantity may probably be safely neglected, but it will sometimes, I make no doubt, be of sufficient magnitude to exert an appreciable influence. I regret my inability to assign any means of determining its amount, and shall merely add that the neglect of this correction will always tend to make the calculated dew-point somewhat higher than the true. Having disposed thus rapidly of the theory of my method, I shall conclude by subjecting the results which it affords to the test of experiment: I shall not at present refer to my own observations, though I have amassed a considerable number on the hygrometer and dew-point. As a more unimpeach- able criterion I shall compare my formula with the observa- tions of others, and shall select for this purpose, it being the nearest to hand, a table published in the last number [Oct. ]834] of Prof. Jameson's Edinburgh New Philosophical Journal. The differences, it will be seen, between the cor- responding numbers of the fourth and fifth* columns, are so small that we may consider them as almost entirely due to errors of observation. I may add, that as in the original table there is no notice taken of the barometer, the formula in its most complete form could not be applied, so that a perfect coincidence between calculation and observation was not in this instance to be expected. January 3, 1835. James Apjohn. * The numbers in the fourth column are the observed dew-points, and those in the fifth the dew-points deduced by ray formula. h 2B2 188 Dr. Apjobn on the Dew-Point. / t' t!' t" Observed. Calculated. 1 68-25 61-75 57-25 57-5 2 56-25 54-5 53-25 53- 3 64.-5 59- 54-5 55' 4 67-5 61-25 55-75 57- 5 67-25 61- 56-75 56-75 6 63- 59- 56-25 56-20 7 62-25 57-75 55-25 54-4 8 68- 61-75 57-25 57-2 9 63-25 59- 56-5 56' 10 69-5 63- 58-25 58-75 11 68-75 61- 56-25 55-66 12 63-5 58- 54-75 53-8 13 63-75 58- 54-5 53-6 14. 68- 61-25 56-^z5 56-6 15 Q5'S 59-75 55-25 57-4 16 69- 62- 57-25 57-3 17 QQ'^ 61- 57-5 57-5 18 66-25 61- 57-5 54- 19 67- 59-5 54-5 54-5 20 64-5 58-75 54-25 54-4 21 64-75 58-75 53-75 49-9 22 59- 54-50 50- 53-1 23 63-75 57-75 53-75 52-5 24, 63-5 57-25 52-25 50-5 25 59-75 5475 49-25 51-25 26 62-5 56-25 51-25 52-75 27 61-25 56-5 53-25 53-25 28 60-75 56.5 53-25 54- 29 62-75 57-75 53-75 57-1 30 65-5 60-5 55-75 58-5 31 64-75 61- 58-25 53-25 32 61-25 57-25 49-75 52-5 33 62-5 57-25 52-75 53-5 34 62-25 56-75 52-75 50-33 35 60-25 56-5 53-75 50-33 36 57-25 53-75 51-5 50-25 37 ... • .. 51- 53-66 38 58-5 54- 50-75 59- [ 189 ] XXXI. An Abstract of the essential Principles ofM, Cauchy's View of the Undnlatory Theory^ leading to an Explanation of the Dispersion of Light ; with Remarks. By the Rev, Baden Powell, M,A., F.R.S.^ Savi Han Professor of Geo- metfy, Oxford. [Continued from p. 113.] TN the motions expressed by equation (^O.)* we may observe ^ that the displacements and velocities depend on the sole variables g and t ; and at the end of the time /, therefore, they are the same for all molecules situated at the same distance § from the plane (16.) to which it is perpendicular. We have thus far obtained expressions forf>)f, the re- solved parts of the actual displacement of a molecule m in the directions of three rectangular axes in terms of »' a'' «'", which represent three distinct absolute motions or displacements in the directions of three lines at right angles in space, deter- mined by the circumstance of their coinciding with the axes of a given ellipsoid, and having determinate inclinations to a given plane dependent on the values of the arbitrary quantities which enter into the expressions. We have also general ex- pressions for the velocities in those directions ; and in general some of the molecules may take each one of the three motions thus defined. Now, if at the commencement of the motion the displace- ment of all the molecules take place in directions parallel to one of the three axes of the ellipsoid just referred to, and the whole velocities are consequently to be estimated in those lines, then the initial values, or tlie functions '^ {g) n{g) ex- pressed by equations (36.) and (37.), will vanish for two of the values of s. And consequently for any time /, the dis- placement a determined by equation (40.) will also vanish for the same two values of s : or, in other words, two of the dis- placements of the molecules will likewise always vanish, or the whole motion will continue always parallel to the same axis of the ellipsoid. We will take a as that one value which does not vanish. Except so far as the remark above made ex- tends, viz. that the motions are the same at the same time for all molecules situated at the same distance from the plane (16.)5 the expression above given for the value « (40.) is not of such a nature that we can directly infer from it the actual conditions of the sort of displacement which a molecule un- dergoes, or the consequences which result ; but we may ar- rive at some conclusions of this kind if we can suppose the 190 Prof. Poweirs Abstract o/M, Caucliy's functions to be subject to a particular condition, viz. that we may have a function ru' (g), such as to give n(g) = fl'oj'ig); (42.) in which case it will be found that the expression (40.) will be reducible to 8 = ID- (g + /2/). (43.) Now, from this form it follows that if g and t receive the respective increments Ag and At, the value of « will remain the same, if we have A§ = -flAt; (44.) that is, the displacement a will be the same for a molecule si- tuated at the end of the time t, at the distance g, from the plane (16.), and for a molecule situated at the end of the time t+ At at the distance g+ Ag. The motion, then, of a molecule m is immediately trans- mitted to other molecules situated on the side on which the values of g are negative ; and the velocity with which the mo- tion is propagated in the direction perpendicular to the plane (16.), which is expressed by the value of —-, given by equa- tion (19.), will be exactly equal to the positive constant /2. Again, it is evident, from the form of the functions (36.) (37.), that they have the same recurring values when we sup- 27r pose g to increase by -r— and consequently the function (43.) 2 If will do the same when g is thus increased, and t by -rrTr' Let us assume 1=^ (45.), and 'T =~ (46.) If now, at the end of the time /, we divide the space into an indefinite number of lamina? by parallel planes corresponding to the values of § which reproduce the periodical equal values dti . . . of 8 or of -TT, then it will evidently represent the thickness of each lamina, while T represents the time of the isochro- nous oscillations performed successively by a molecule. We will call these laminae " plane waves," and we will suppose their thicknesses divided into two equal parts by that one of the parallel planes whose equation is ax-\-bi/-\-cz = g = —Sit, (47.) View of the Undulatory Theory of Light. 191 Then for the points through which these planes pass, we shall have constantly « = w(0), and -^ = /2^(0); (48.) or, what is the same thinp;, from (36.) (37.)j « = doA + eoB+foCand^=it/2(goA + hoB + ioC) (49.) And for the planes bounding the waves successively, « = .(i-) ^=^n.'(L)., (50.) or, what is the same thing, « = -[doA + eoB + foC] and ^= -^/2(g^A + hoB + ioC] (51.) Further, the velocity of the propagation of a plane wave, or, in other words, the velocity of the displacement of the plane (47.) measured perpendicular to it, will he constant by virtue of the formula (47.), and represented by ft. If we suppose the functions such as to fulfill the same con- ditions as those of (42.) with only the difference of the sign, or 11(g) = -/2^'(^), (52.) the same considerations readily show that we should have 8 = m (g-nt), (53.) and by consequence, in the same way as before, Ap = SlAt, (54.) The inference, then, will here be that the motion of m is immediately transmitted to molecules on the positive side, the velocity being still the positive constant ft. It may also be observed in either case, that the formula which determines 5 in functions of 1c for a given direction of the plane (16.), will also determine T or /2 in functions of/. If, however, the functions U (g) and m [q) be such that the condition (42.) is not fulfilled either with the positive or ne- gative sign, then we cannot proceed to determine the value of a by the conditions involved in the former investigation ; that is, it will follow that the formula (39.), or the three si- milar formulas involving the three values of 5, will not enable us to determine the nature and conditions of the three displace- ments in directions parallel to the axes of the ellipsoid. But we may consider the value of s as representing a motion pro- duced by the composition of six motions (three on each side of the given plane), each corresponding to that represented by the equations (43.) and (53.)? according to their signs. The plane waves corresponding to each of these six mo- 192 M. Cauchy's View of the Undidatory Theory of Light, tions will propagate themselves in space with velocities equal, two and two, but proceeding in opposite directions, and re- presented by /2', /2", /2'". We have already observed that from the form of the func- tions (36. 37.)> Sq ^^^ »i ^^ve recurring values when q is increased by —j- ; and the similar remark made with respect to the function (43.), it will also be seen, is not restricted to that particular case, but applies equally to the general formula (38. )j when t is increased by t7>. Thus, then, adopting the notation of (45. 46.) for the intervals of recurrence in space and in time, we have directly from those expressions /2 = 4" (55.) Or we find in general that there is always a constant relation between the length of a wave and the velocity of its propaga- tion ; or, in other words, that the velocity of the propagation is directly as the lengths of the waves, and inversely as the times of the oscillations of the individual molecules of the aetherial fluid ; or, what is the same thing, the interval of the time of the recurrence or arrival of two successive waves at the same point. It must be recollected that, in order to simplify the investi- gation, we have proceeded solely with reference to a single displacement in the direction of each of the axes ; or, more precisely, it has been conducted on the assumption made at first, that we might consider each of the expressions (17.) as reduced to a single term : those expressions, however, really involve the sum of a number of similar terms. In the ex- pressions (23.), therefore, which represent the initial values of f »j ^ and of their differentials, as well as in the equations (33.), the same consideration must be attended to, that is, we must take f 0 = -^ [^0 cos A: g + go sin Jc q] {5(5.) &c. f 1 = JS* [di cos ^ ^ + gi sin k q] (57.) &c. f = 5* [A' «' + A" 8" + A'" «'"] (58.) &c. We shall then have only to introduce the values of a' «" «"' as above found, and the motion of the system may be considered as produced by the combination of many, or even an infinity of similar motions, each the same as those represented by the equations (43.) and (53.). Finally, in order to complete the analytical view of the sub- Mr. Everitt on separating Manganese a?id Iron. 193 ject, M. Cauchy proceeds to show how the sum of terms in- dicated by -5* may be changed into definite integrals. In this investigation it will not be necessary to our purpose to follow him, but we shall proceed to some remarks on the expressions above deduced and their physical applications. [To be continued.] XXXII. (Economical Meaiis of procuring pure the Salts of Manganese^ and of analysing the Minerals 'mhich contain Manganese and Iron^ S^c, By Thomas Everitt, Esq.,, Pro- fessor of Chemistry to the Medico-Botanical Society, Sfc* TTAVING had occasion for some pounds of pure salts of ^ manganese for experiments on dyeing, my attention was turned to consider the convenience and oeconomy of those processes prescribed in our systematic works. The process of Faraday by hydrochlorate of ammonia, is easy of execu- tion, and perfect as to the results, but expensive; that of Turner, " by mixing the oxide left after procuring oxygen gas by heat with one sixth of charcoal, and exposing to a white heat for half an hour in a covered crucible, dissolving in hydrochloric acid, evaporating to dryness, and keeping the mass in perfect fusion for a quarter of an hour, &c." yields also good results, but is tedious in the execution, and expensive, if time and trouble be considered ; moreover, by the first igni- tion, although we subsequently save a little hydrochloric acid (none being lost as chlorine) by reducing the manganese to protoxide, we also at the same time render the iron in such a state that on dissolving in hydrochloric acid, we have a protoxide, which is more difficult to get quit of by the second ignition than it would have been as a peroxide. As I possessed a large quantity of hydrochlorate of man- ganese and iron, the accumulated solutions from preparing chlorine by hydrochloric acid and ordinary oxide of man- ganese, I was induced to make a variety of trials on this li- quid with the view of separating the iron from the man- ganese ; the results of which trials being entirely satisfactory, I venture to request a place for a short account of them in the London and Edinburgh Philosophical Magazine. Method, No. I. — Depending on the circumstatice that when a solution of hydrochlorate of iron, strictly peroxide (which is always the case in the above liquid), is evaporated to dryfiess^ and the heat afterwards slightly elevated, a small portion sub- * Communicated by the Author. Third Series. Vol. 6. No. 33. March 1835. 2 C 194? Mr. Everitt on oeconomical Mean$ limes as per chloride : the rest is decomposed into free hydro- chloric acid and peroxide, which re?naijis behind. Tlie clear decanted or filtered liquid, generally acid and of a dark colour, is to be evaporated to dryness in a porcelain dish, when a mass of small bright yellow crystals will be ob- tained. The heat of the sand-bath is now to be considerably increased, when, by constantly stirring the mass, taking care to heat the sides as well as the bottom of the dish, it soon ac- quires a gray ashy aspect; and if the operation be continued till hydrochloric acid gas ceases to rise (this to be ascertained by holding a rod dipped in ammonia over it), we obtain, on pouring water on it and filtering, a colourless liquid, contain- ing all the hydrochlorate of manganese and no iron, since it will be found to give a white precipitate with yellow ferro- prussiate of potassa, having no blue tinge. This latter part of the process may be conducted with much greater dispatch by putting the dry yellow salt into an ordinary iron ladle, and stirring with an iron rod over a slow fire till it becomes ash- gray, or till all hydrochloric acid fumes cease to rise. The heat never requires to be raised near redness so as to fuse the mass ; for small quantities this part of the operation may be performed in a platina crucible. Having a pure hydrochlorate, of course all the other salts can be obtained : the carbonate by precipitation with car- bonate of soda, filtering, washing, &c., and from it any salt or preparation required by the scientific chemist. Should the manganese ore have originally contained ba- rytes or lime, these must be removed from the solution before precipitating the carbonate of manganese, the first by a little sulphate of soda, the second by a little oxalate of ammonia : this, however, does not remove the last traces of lime — (ac- cording to Turner), Method, No. 2. — Depending on the circumstance that car- bonate of manganese will precipitate peroxide of iron when boiled in a solution of any peroxide salt of this metal. Add to the filtered solution of hydrochlorate of peroxide of iron and manganese, a small quantity of carbonate of soda, so as to precipitate a small portion only of peroxide of iron and carbonate of manganese : now boil for five or ten mi- nutes, when the carbonate of manganese will be redissolved, throwing down and replacing the peroxide of iron. If, on filtering a minute quantity of the solution, some iron is still found to be present, by its yielding with yellow ferro-prussiate of potassa a precipitate tinged with blue, a little more car- bonate of soda is to be added, and the liquid boiled again : a very little experience will enable the operator by this means to free the solution entirely from iron, and at the same time to of obtaining -pure Salts of Manganese, W5 have a very small portion of carbonate of manganese remain- ing with the precipitated peroxide of iron. The filtered so- lution will now contain nothing but hydrochlorate of soda and hydrochlorate of manganese, and from it the pure car- bonate of manganese may be obtained as before. A slight modification of this process may be made if we require at once a pure hydrochlorate of manganese free from all salts of soda or potassa. Add to the compound solution, freed from excess of acid by partial evaporation and resolu- tion, some carbonate of manganese, enough to replace the peroxide of iron ; boil for some time, filter, &c. : or, if the operator have no carbonate of manganese, take a portion of the liquid apart, precipitate by carbonate of soda all the iron and manganese, and wash well ; then remove the still wet mass from the filter, consisting of carbonate of manganese and peroxide of iron, add this to the remaining liquid and boil,^ when, as before, the rest of the iron will be precipitated and replaced by the manganese. Of course the portion of liquid which must be precipitated apart depends upon the relative quantities of iron and manganese in the solution, and on the quantity of free acid : in my experiments -^-q of the solution was sufficient to furnish enough of the precipitate to effect the entire purification of the remaining ^g ; but I had removed nearly all excess of acid by evaporation. This process is peculiarly adapted to the purification of a solution of hydrochlorate of manganese containing only a trace of iron, saving thereby the trouble of evaporating the whole of the liquid and igniting: thus, I found in one of mv trials that I had four pints of a strong solution of hydro- chlorate of manganese containing only a trace of iron ; the evaporation of all this to dryness and igniting would (seeing it contained more than a pound of hydrochlorate of manga- nese,) have been a very long and tedious operation, but by adding a few grains of carbonate of manganese, and boiling for a quarter of an hour, it became quite pure. It must be borne in mind that the success of these methods depends entirely on the iron being strictly peroxide : should any protoxide be present, this must be peroxidized by the addition of nitric acid. I find that carbonate of manganese free from iron can also be procured from the liquid obtained, on dissolving the mass left after procuring chlorine by common salt, oxide of man- ganese, and sulphuric acid,— by the method. No. 2. Hence, the dyer, potter, or glass-maker can now have, at a trifling expense, all the preparations of manganese chemically pure ; and the absence of iron is of much importance in many of their applications in the arts, a subject which has for some 2C2 196 Mr. Blackburn's Analjjtical Theorems time been the object of my experiments, and for an account of some of the results of which I may at a future day beg a place in this Journal. The second part of this paper, containing the application of the above principles to the analysis of minerals containing manganese and iron, and an examination of those methods now used, will appear in a future Number. 28, Golden Square, London, December 12, 1834. XXXIII. Analytical Them-ems relating to Geometrical Series. By Charles Blackburn, A.B, To the Editors of the Philosophical Magazine and JourJial. Gentlemen, T^HE following properties of numbers have not been noticed -■- in any work of Algebra that I am aware of. If on inspec- tion you find them to be new, you may think them sufficiently curious for insertion in your Philosophical Journal, It seems not impossible that they may admit of some useful application in analysis; but at any rate they may be of service to persons entering on the study of algebra, or even to per- sons engaged in tuition, from the inexhaustible fund of ex- amples the formulae will supply. They are exhibited in the forms they assume when r is negative as well as positive ; and when the number of terms is even as well as odd. Three of them have already appeared before the public, but without any demonstration; they are here inserted with the investigations. Kensington, Feb. 23, 1835. Theorem I. 1 . S'*^ 2.2'* (W-1)2" ^'■^ l+r + r^ r»-' =0-^ + ^^ »• ' x{l-»- + r* +/"-')n X {i_y+X~.'... rC"-')*""'} "" beinsrodd. Let l+r^%'-^-^" + rC«-')2''=S, 't> 1+ r + r^ + r = s; then, since each of these is a geometric series, we have n ?h2 S _ ('•'"-!) (>•-■) (a). 's (r"'-l){r'"-X) relating to Geometrical Series. 197 But r"''- 1 = (r "••% 1 ) (/"'''+?) (r" + 1 ) ('■"' - 1 ) to 7t + I terms ; r'^— 1 = (r f 1) (r^ + l) (r+l)(r-l) to w -f- 1 terms ; therefore, by substitution, in equation («), we have A ^ (r^V 1) (r^-'^'^'f 1) (r^-4-1) (r^-l)(r-l) (r-7l) (r^Tl) (r+1) (r-1) (r"-l)- By elimination and separation of the factors, n— 1 n—2 r -i- 1 r +1 r + A y -f 1 r^^-' + l r^'^-Vl to w terms. Bui r+i =, ,.('»-l)2_,.(— 2)2 ^ ^2.2 _ ^.2^ J TO — 1 r« + 1 n-2 &c. &c. &c. &c. r 4-1 m—l 7/1—2 =r — r + r^—r-\-l,Gdch series to w terms. Hence by substitution in equation (Z>.) we have ^+'-' +'-^"+ ' '=(l-r+r^ +r"'->-l l+r+r'+ r"*-' L / x{l-rV»" +,('»-»n l-/+^2V r("-'^' J- to w factors of m terms each. Or, as it may be more compendiously written n --n o^ 2.2' (f»-l)2" 2 1+r +r +...+r l+r + r^+ +r'' -=|l~r+r^ r-»j. 198 Mr. Blackburn's ^w«/?///c«/ Theorevis where the index n shows that there are n factors, and the index 2 that the indices of each succeeding factor are double of the preceding. (2.) Hence it appears that if an odd number of terms of a geometric series be raised to any power of two, the sum of the terms so raised is divisible by the original series. Also that the quotient consists of a number of factors, each of which is a geometric series of the same number of terms as the original one, having the signs of the alternate terms ne- gative, the number of series or factors being denoted by the index of two. The first factor is the original series with the signs of the alternate terms changed, and the indices of each succeeding factor obtained, by doubling those of the pre- ceding. Example, Let w = 1, then by the formula 1 I 3 ■ 4 . (m— 1)2 — ^ — = 1— r + 7-+ r l4-r+r^+ 7-^-1 or, jl+r + r^+ r^^-^} .{i-r-fr^- i^'-^\ = l+r^ + r'*+ r^»*-^)2 from which it appears that if an odd number of terms of a geometric series, be multiplied by the same terms with the signs of the alternate terms changed ; the product will be the sum of the squares of the original series. (% \ Cor ^^ ^ -^ "• ^ (J.; car. ^^ (m-i)/c 1 +r +r + r = |1— r +r — ^ r^ ' j . (4.) Cor, 2. Every algebraical expression of the form l-fr^ _|.,.2-2 +... /"»-!) 2 Ij. divisible into ;;+l factors, each of which is a geometric series of m terms, and y; of which factors have the signs of the even terms negative, thus 1+^2 + ;. 2.2'; ^(».-l)2''= |)+;.+,.2+ ...r"-'} X ^X-r + r"^- ,.'»-' J- X relatim to Geometrical Series. 199 •to It may be observed that this formula retains the same signs whether r be positive or negative. (5.) If each side of theorem I. be multiplied by the quan- tity 1+r + r -f- ... — r +r , s n ;j we have 1— r + r — ... — r -\-r Theorem II. 1 +r2'» ^^2.2»*_^ ,.(''»-2)2'»_^_^(m-l)2n 1-r + r- ,,m-2_^^m-l = {l+r + rV r— Vr-^'}X {l-r%r^-. ^(.-2)2^^.(-i)2| ^ &C.&C.&C X |^l_,.2%>2!:^c r^m-2)2''-]im-^)2''-^^^ tO 72 factors of m terms each ; or, l+/V,-''-^+&C ^(m-2)!i'^^(m-l)2'' , , 2 o w— 2 m-1 1— r + r — &c r -j-r — J -1 . .2,0 m—2 , w — 11 -. = |l+r + r+&c r +r ]• x 2{ !_,%.«_ +,(™-')2}n-l . (6.) Cor. y^r'='\r^'''\ ,.(^-.)^^" - ^ , 2A- (m-\)k 1 — -r 4-r — r^ Theorem III. (7.) Let ^, 5^, r be any numbers of which p y q and m an odd number, then l+r^ + r^-^&c ,.(«-ii)i!%,.(^-l)ii'' X+/+r''-^\^C ,.(m-2)2t,.^(».-:)2' 200 Analytical Theorems relating to Geometrical Series, X . , X &c. &c. &c. Dem, ^ ^jP »P ^ ,^ n^nP By Art. 1 = ^|l-,.4.^2_g^^ ^m-2^^,m--iy\ By dividing each side of the equation by l—r + r^-&c. 'm—2 . m—l .... — r -\-r we get — Dividing each side by l-r^ + r^'^ y(»— ^j^^/m-^a we have and by performing the division in like manner q times, we have at length Mr. G. O. Rees on theTresence of Titanium in the Blood, 20 f Or, l+r^%l^-^+ r("-')'" 1+^2' +,.2-2; /«.-i)2' X {i-/->"- .C"-)^"-'} to p — q factors of wz terms each. 8. From this it appears that if an odd number of terms of a geometric series be separately raised to the power of 2^', and divided by the same terms raised to the power of 2^, the quo- tient will consist of p — q factors, each of which is a geometric series of the same number of terms as the original one, with the signs of the even terms negative. [To be continued.] XXXIV. On the Presence of Titanic Acid in the Blood, By Mr. G. O. Rees. To Richard Phillips, Esq., F.R.S., ^c. Sir, XrOU will much oblige me by inserting the following ex- -*- periments in the London and Edinburgh Philosophical Magazine and Journal of Science. Your obedient Servant, G. O. Rees. While making some further observations on the presence of titanium in organic matter, I was induced to examine the blood, in order to assure myself that its existence in that fluid had not been overlooked. For that purpose the following experiments were made. A portion of incinerated blood was digested in strong nitro-muriatic acid at a boiling tempera- ture: the solution so formed was decanted from the insoluble residue, which consisted of granular white particles in admix- ture with a portion of carbon thiit had escaped dissipation. The decanted solution was evaporated to dryness. Very dilute sulphuric acid was next boiled on the dry mass for a few mi- nutes, when a considerable quantity of a fawn-coloured powder was observable at the bottom of the vessel : this powder was Third Series. Vol. 6. No. 33. March 1835. 2 D '802 Mr. G. O. Reeson the Presence of Titanium in the Blood, washed with distilled water, dried, and heated to redness in a platinum crucible ; it became of a dark colour, and when cold had a distinct reddish hue, owing, doubtless, to a portion of phosphate of iron in admixture, as that substance does not redissolve with the dried chloride. The mass was therefore boiled in aqua regia, when a light coloured powder was left undissolved : this, on being examined before the blowpipe on a platinum support, gave a yellow bead (becoming colourless when cold) in the outer flame ; and a yellow bead, becoming reddish while cooling, and purple inclining to blue when cold, if the inner flame was directed on it. A second portion of incinerated blood was similarly treated, excepting that the dried chloride was (as several digestions with aqua regia were had recourse to) each time washed away from the mass in the vessel used for the digestions. By this means a residual mass was procured, of a white colour inclin- ing to gray; this was fused with carbonate of soda, which produced a yellow colour when heated, becoming nearly white when cold. Distilled water was boiled on the fused mass, when a light flocculent white precipitate was seen floating in the liquor, and a heavier fawn-coloured powder (which gave the reactions of titanic acid before the blowpipe) appeared at the bottom of the vessel. The flocculent precipitate was col- lected and dissolved in cold dilute muriatic acid : the solution gave a dark green coloured precipitate when neutralized with ammonia and tested with hydrosulphuret of ammonia, and a reddish brown precipitate with infusion of galls; the sul- phuret when collected and ignited behaved as titanic acid before the blowpipe. In every specimen I have examined, an insoluble residue has been observable, though strong nitro- muriatic acid has been used as a solvent : this insoluble matter in every instance has been of a white or dingy white colour, becoming yellow when fused with alkaline carbonate, but not exhibiting that phaenomenon when heated alone to the same extent as the titanic acid of the mineral kingdom. As I have not yet made any quantitative analysis of the incinerated blood, I cannot say that the iron exists as titanate in that sub- stance, though titanic acid be present; but its behaviour would seem to indicate the necessity of such being the case. I have only to add, that a recent communication regarding the existence of titanic acid in Hessian crucibles can in no way interfere with any of my observations, as the whole of the crucible experiments I have detailed were conducted in platinum vessels. Guy's Hospital, Feb. 12, 1835. [ 203 ] XXXV. On the Attraction of an Homogeneous Ellipsoid on an external Particle. By J. B.* T ET a, h, c be the semiaxes of the eUipsoid, a the greatest -*-' and h the least, 8 = distance of external particle from the centre, assumed as the origin of coordinates, A, |x, v the angles which the line 8 makes with the semiaxes a, 6, c, M = mass of the ellipsoid, jx the external particle, andy the intensity of attraction at the unit of distance, D the attraction along the line 8 ; then in the expression V = 1 1 f—^y expanding -k-> multiplying by dm^ integrating and including the terms as far as the third powers of the coordinates of dm, and making the necessary reductions, we have this general formula : j^_f/^M f , L 3 ^(3 cos'^A— 1) a^+(3 cosa ^— l)&^-f (3 cos'^u- 1) c% ) 2« Let A, B, C be the attractions on three particles at equal distances from the centre in the axes produced; then I' {^^l^-^^)} B..^^^{,,-|(^^!r^)}; ./>M 8« ^ ^ 2h^ -a^- -(? S^ 2c'- -a^- -¥ Adding these three formulae, A + B + C = ^^ — , or the sum of the attractions of an ellipsoid on three particles at equal distances from the centre in the axes produced = three times the spherical attraction of the same mass on a particle at the same distance. 3. Hence, also, the attraction of the ellipsoid is greatest in the direction of the greater axis, and greater than that of a sphere of the same mass on an equidistant particle ; and that in the direction of the lesser axis is the least. 4. If the squares of the semiaxes are in arithmetical pro- gression, the attraction of the ellipsoid on a particle situated in the mean axis = to that of a sphere of the same mass on a particle at the same distance, for (2c'— a*— 6*) in this case = 0. 5. Let there be two homogeneous concentric ellipsoids of * Communicated by the Author. 2D2 204? J. B. on the Attraction of an Homogeneotis Ellipsoid. the same density, whose semiaxes are «, h^ c and a, /3, y re- spectively, such that a^—c^ = a^-— y* = F and c^^b^ = y^ — /3- = /i^; and let two particles be assumed, p and -cr, whose coordinates are /a, ?w /S, w y, and la^mb, nc\ l^-\-m^-\- n^ being = 1, it can be easily shown that the particles jf? and -crare on the two ellipsoids. Calling the external ellipsoid E and the internal one I, then the attraction of E on -sr is to the at- traction of I on jD, in a direction perpendicular to one of the principal planes, as the product of the axes of E in that plane is to the product of the axes of I in the same plane ; which is the celebrated theorem given by Mr. Ivory. First, let the particles p and txr be situated at the surfaces in the axes of y and c, then Z = 0, m = 0, and « = 1, and the attraction of I on p is by the formula as 4^/g/;cf, 3 (2c'-a^-¥y^'\ 3y^ f'^loV y" q {i+ To (-/-)}> p is as ""37 |^"^10^ y^ if " " 3y^ Y'^ loV y^ J I' Hence the attraction of I on ^ is to the attraction of E on the same particle p as abc: oL^y. Now, if through the in- ternal point -cT an ellipsoid similar to the external E concen- tric, and similarly situated, be drawn, the attraction of E on p : the attraction of E on -cr : : y : c ; therefore the attraction of 1 onpi the attraction of E on tzr : : « Z> : a |3. Now, if the particles be not at the extremities of c and y, let their coordinates to the plane o^ xy he.nc and ny, and let the particles be^' and ts' ; then the attraction of E on the particles p and p^ is as their perpendicular distance from a principal plane as y and n y : i \ : n. In the same way the attraction of I on -cr and -or' : : c : w c : : 1 : w. Hence attraction of I on p' : attraction of E on -or' ::« 6 : a |3. 6. Should the ellipsoid become an oblate spheroid a = c, and let a^—b'^ _ ^'Kfabc ~ 3y^ and the attraction of E on p is as {'+i^4^(— v)f 7. When cos'^ ju. = -— , the attraction is the same as that of Prof. Forbes on the Refraction and Polarization of Heat. 205 a sphere of the same mass on an equidistant particle, but cos ju, is nearly = sine of latitude ; hence the attraction along a line which makes with the axis an angle whose cos = — ==, is the same as that of a sphere of the same mass. 8. When the particle is on the equator of the oblate sphe- roid 8 = a and |!x, =90° ; hence A = -——'{ 1+ -rx ^^ k and if e be small e^ = 2 6 nearly ; hence A = — ^S 1 + -^ e (-• 9. If the particle be at the pole of the oblate spheroid 8 = 6, and neglecting powers of e above the first. r-*-i^{'-i-}- 10. Should the ellipsoid become a prolate spheroid round the axis of a, the formula becomes ^ /Mr,, 3/3cos^X-l. aol,, . If the point be at the pole of the spheroid cos A =1, and 8 = a, and the formula P' = 4<7rfb {-i-l 3 11. If at the equator 8 = Z> and cos A = 0 and the formula becomes B = — ^ — J 1+ — s r, omitting the powers of e above the first. Trinity College, Dublin, Nov. 12, 1834. XXXVI. On the Refraction and Polarization of Heat, By James D. Forbes, Esq,^ F.R.SS. L. SfE., Professor of Na- tural Philosophy iii the University of Edinburgh, [Continued from p. 142.] § 2. On the Polarization of Heat by Tourmaline. 18. T T is well known that two slices of tourmaline cut parallel ^ to the axis of the crystal, as they are looked through with their axes parallel or perpendicular to one another, transmit a great portion of the incident light in the one case, and almost wholly intercept it in the other. 1 9. It occurred to me as a curious question, at an early pe- riod of my researches, whether non-luminous heat would un- 206 Prof. Forbes 07i the Refraction and Polarization of Heat. dergo any similar change in similar circumstances. I made a preliminary experiment with heat from an oil-lamp (not an Argand), and though, when the axes were crossed, the whole light was stopped^ the heat transmitted appeared to be as in- tense as before. The tourmalines which I employed were mounted on glass, and were kindly lent to me by the Rev. Mr. Craig. Struck with the singularity of the result, I re- peated the experiment with additional precautions, and I found that some circumstances prevented this statement from being true in all its generality. The quantity of heat transmitted being very small, the lamp, the tourmalines, and the pile were very near to one another; and, as the tourmaline absorbs heat with great rapidity, I found that a minute difference might exist if the experiment was made first with the axes parallel, and then with the axes crossed, which difference might yet be made up by the secondary radiation from the heated tourmaline, which was constantly becoming more in- tense. Such at least appeared to be the chief source of error, which I am particular in stating, because I afterwards dis- covered that M. Melloni had been led to the very same con- clusion as I at first was, and had published it. 20. When I proceeded to verify my results by a series of successive observations, under the two conditions of axes pa- rallel and axes crossed, so as to eliminate any error from a constantly progressive change, I perceived my mistake. As this illustrates the method by which almost all my observa- tions have been reduced, I shall give an example. Two mea- sures of intensity in the position where least light was trans- mitted, which is marked Dark, have their mean taken, which is then compared with the intervening observation in the po- sition of greatest illumination, which is marked Light, These tourmalines we may call A and B. 1834-, Dec. 4. — Oil Lamp* six inches from Centre of the Pile, Dark. Mean. Light. Ratio. • 4 } } \ } o o 4| Si 4-5 5-0 5-2 6-0 86 : 100 83 : 100 5 5-2 5-4 6-0 6-5 86 : 100 83 : 100 Deviations of galvanometer. ♦ The oil lamp used when not expressly called « Argand," was Locatelli's lamp with a solid square wick, which is what M. Melloni employed. Prof. Forbes on the Refraction and Polarization of Heat. 207 Another series on a different day gave the following quantities per cent. 91, 82, 94. Mean of the whole, 86*4< : 100. 21. Having obtained these decisive results, I proceeded to operate with other sources of heat, and with different tourma- lines. Anxious to avoid the interposition of glass, I had a pair of tourmalines of large size cut without any support. But the best kind will not bear this, and they polarized imperfectly. Only fifteen sixteenths (approximately) of the light in the bright position was stopped in the dark, whilst with the tour- malines A and B every vestige of the brightest gas flame was excluded. With these tourmalines (which may be called C and D) I verified the general conclusions. I was unable to get sufficient effect from non-luminous heat to verify the law in that case. 22. I had two very fine tourmalines cut and mounted on ex- tremely thin glass. These we may call E and F, With them I was enabled to extend and verify the law of polarization even to the case of non-luminous heated brass, (whose temperature when warmed by alcohol, M. Melloni estimates at 390° cent. = 734° Fahr.) And it is worthy of observation that among twenty-nine pairs of comparative observations, made with three sets of tourmalines, and heated from the following sources, Ar- gand lamp, simple oil lamp, platinum rendered incandescent by alcohol, and non-luminous hot brass, there was only one which did not give positive indications of polarization. The effect, however, with non-luminous heat is extremely feeble, and the percentage very small, because it is with great difficulty that we can obtain results at all with the interposition of two plates of glass, and two of tourmaline (however thin), and a large portion of heat which reaches the pile is derived from conduc- tion, and therefore diminishes the proportion of polarization. 2S. It is very important to observe, that in this and all simi- lar cases, the effect of conduction or the secondary radiation of heat from screens always tends to disguise, and never to produce the differences of which we are in search ; that is, so long as the means of alternate observations are taken in the way we have described. 24. The following are the general results of my experiments on tourmaline. Source of Heat. No. of Comparisons. Proportions of Heat polarized by AandB EandF Tourmalines A and B EandF* Argand lamp, 3 16l U Oil lamp, 7 3 14percent. 11 (§ Incandescent platinum, 4 3 15 ... 12 j u Brass at 700°, 7 (1 negative) 3 J £- * It appears that the axes of E and F were not precisely crossed in these experiments. 20S: Prof. Forbes on the Refraction and Polarization of Heat, I cannot, therefore, entertain any doubt on the polarization of heat by tourmaline, notwithstanding the opposite result which M. Melloni (and I also at first) obtained. 25. Some very curious considerations arise from the study of these facts. Since 84 per cent, of the heating rays of an Argand lamp pass through the second tourmaline in the case where the light is entirely stopped, we must adopt one of two conclusions : either that the heat which necessarily accompa- nies light is excessively small, or else that radiant light during its instantaneous passage through a medium, is capable of being converted into radiant heat. The latter supposition we have no analogies strong enough to warrant us to adopt, though were heat really not polarized by tourmaline, we must have done so. All our experiments point to the first, namely, that heat, though intimately partaking of the nature of light, and accompanying it under certain circumstances (as refrac- tion and reflection), is capable of almost complete separation from it in others. Thus, almost all the heat is stopped by a plate of alum, which transmits nearly the whole light, whilst a second plate of tourmaline stops the whole light, but transmits a large share of the heat. 26. The tourmaline affords a precious method of investi- gating the influence of light, since the quantity of matter to be traversed is exactly the same, whatever be the direction of the axes of the crystal. In this it differs from all other modes of absorption. 27. M. Melloni has proved that the more light that accom- panies heat, the greater power it has to traverse most media, such us clear glass or alum. I made several experiments on the quality of the heat which passed through the tourmalines in their darkest and in their brightest positions, and I always found that the presence of the light materially increased the power of the heat to permeate such screens, though we have seen how little it added to the quantity, 28. This fact, namely, that by sifting, as it were, heat sepa- rate from light, we give to it the characters of non-luminous heat, or heat of low temperature, and small refrangibility, such as exists beyond the red extremity of the spectrum, seems so far congenial with analogy. But according to Melloni's ex- periments, this does not hold with other degrees of sifting of heat. Thus the absorption of all rays of light, except the blue, the yellow, or the red, by coloured glasses, does not give the peculiar character to the heat which it possesses, when it ac- companies light in the process of refraction, namely, that of permeating screens (in general) more readily as the refrangi- bility is greater. Hence I conceive we must conclude, that Prof. Forbes on the Refraction and Polarization of Heat, 209 heat in the spectrum accompanies the hght, and has corre- sponding properties, but that in genera] these properties are independent of the nature of the accompanying light. 29. The only fact which appeared to militate against this view, so far as coloured media were concerned, was the case of green light. It appeared probable that this arose from some peculiarity in the absorptive nature of the material, not from its colour. To investigate this point, I tried the relative trans- parency (or diathermancy, to borrow a word from M.Melloni,) of screens for the heat of various coloured flames. I did not find that marked peculiarity in the green, which M. Melloni observed in the absorptive action of green glass. The fol- lowing results are not pretended to be numerically accurate, but they are probably nearly comparable. The flames were obtained from alcohol, » combined with the following sub- stances: for the red, nitrate of strontia (the muriate is better); the yellow, with muriate of soda ; the green, boracic acid ; the blue, pure alcohol. The unsteadiness of intensity of an al- cohol flame prevents great numerical accuracy. Number of Rays of Heat out of 100 transmitted by Colour of Flame. Alum. Glass. Rock Salt. Red, 11 26 85 Yellow, U\ 28 87 Green, 11 26 84- Blue, 10 30 83 The differences are certainly within the limits of errors of observation. 30. I am disposed to believe, however, that in these expe- riments, as well as Melloni' s, some effect is probably due to the simple presence of light of a particular quality, though its heating power may be small. This my experiments with tourmalines countenance. We can hardly, however, look for a solution of these difficulties, until some of the most stubborn difficulties in the theory of light, the laws of dispersion and ab- sorption (and especially that peculiar absorptive power which permits the tourmahne only to transmit one polarized pencil,) are completely overcome. Meanwhile, we pass with pleasure to the consideration of some of those properties of heat which serve to connect it with the best determined and best explained departments of optics. § 3. On the Polarization of lH.eat by Refraction and Refection, 31. Soon after the discoveries connected with the polariza- tion of light, which illustrated the earlier part of this century, the question of the polarization of heat was taken up by Malus Third Series, Vol. 6. No. 33. Ma7ch 1 835. 2 E 210 Prof. Forbes on the Refraction and Polarization of Heat, and Berard.* In the case of heat accompanying solar light, it was decisively proved, as might have been anticipated ; but in the case of heat from terrestrial, and especially non-lumi- nous sources, though M. Berard considered that he had proved it, he gives no quantitative measures which could enable us to judge of the evidence, nor does it appear that subsequent ex- perimenters have been able to verify the assertion.f 32. The importance of the subject will be estimated, when we consider the very definite laws to which the polarization of light is subjected, and the accuracy with which they are repre- sented upon the undulatory hypothesis. If heat, when wholly deprived of light, be subjected to similar modifications, our progress in acquiring a knowledge of the true nature of heat will be greatly advanced by our previous analogical acquaint- ance with the laws of light.J 33. I had been led to make the experiment with tourma- lines, because of the convenience with which all experiments on transmitted heat are made by means of the multiplier. But at the same time it occurred to me, that the transmitted pencil of heat passing through laminae at the polarizing angle might likewise be adapted to the instrument. I had previously noticed the large proportion of heat transmitted by thin plates of mica, and I thought of applying bundles of mica-plates placed at the polarizing angle, and so cut from the plate, that • Memoires d'Arcueil, torn. iii. t See Professor Powell's papers in the Edinburgh Journal of Science, Second Series, vols. vi. and x. J The importance of analogies In science has not perhaps been suffi- ciently insisted on by writers on the methods of philosophizing. A clear perception of connexion has been by far the most fertile source of discover}'. That of gravitation itself was only an extended analogy. The undulatory theory of light has been preeminently indebted to the co-ordinate science of acoustics, which afforded to Dr. Young the most plausible basis of his cu- rious and original investigations; and unless that science had existed, it may be doubted whether such a speculation would ever have been invented, or, if invented, would have been listened to. The penetrating sagacity of M. Fresnel, in Ins prosecution of the subject, has led him to draw from me- chanical and mathematical analogies, accurate representations of laws which no strict reasoning could have enabled him to arrive at. Of this his mar- vellous prediction of the circular polarization of light by two total reflec- tions in glass, is the most prominent example, a conclusion which no general acuteness could have foreseen, and which was founded on the mere analogy of certain interpretations of imaginary expressions. The mere reasoner about phaenomena could never have arrived at the result, — the mere ma- thematician would have repudiated a deduction founded upon analogy alone. The cause of the long postponement of the discovery of electro- magnetism was the complete apparent breach of analogy between the modes of action of the electric and magnetic forces, and any others previously known. Prof. Forbes on the Refraction and Polarization of Heat, 211 the plane of incidence corresponded with one of the neutral sections of the mica-plate, (the section used was th^it perpendi- adar to the principal plane,) so that the transmitted pencil would be polarized exactly similarly to that refracted through glass or any singly refracting medium. 34-. 1 prepared two pairs of bundles of plates of mica of this description, the first (which I called A and B) having a thick- ness of about one fiftieth of an inch, and was split into about ten plates, whilst the others (C and D) were only half the thickness, and contained but half as many reflecting surfaces. I found that these plates, placed at the proper angle, polarized light very satisfactorily. On applying them to heat, I had the satisfaction of finding that not only was heat from an oil lamp most decisively polarized, but also that from a brass plate warmed by alcohol, but so as to be quite invisible in the dark, having probably a temperature (as before mentioned) of about 700° Fahr. These experiments w^ere made on the 22nd of No- vember last, and were afterwards amply confirmed*. 35. It is to this mode of observing that I attribute chiefly the success of my after inquiries. The mode of reflection for polarizing is attended with so much inconvenience where a thermometer is concerned, and especially with the multiplier, as to render the employment of it tedious and incommodious; whereas by having two bundles of mica-plates arranged in square tubes, so that the one fits the extremity of the thermal pile, and the other slips into the first, and by turning it round we get observations with plates, whose planes of incidence for rays passing along the axis of the tube, are inclined 0°, 90°, 180°, or 270° to one another, the direction of the ray is gene- rally in a single straight line, and the observations are made in the same manner, and with equal facility as in ordinary ex- periments on transmission. I have little doubt that in this way the polarization of heat might be proved without the aid of the thermo-multiplier. The plates were fixed at the po- larizing angleybr light. After what has been said, art. (16), on the refrangibility of heat, it is clear, that the alteration of the polarizing angle, in order to accommodate it to heat, could hardly amount (by Sir David Brewster's law) to a sen- sible quantity. * I did not see M. Mellon i's second paper till the 10th of December, after I had obtained the chief fundamental results contained in this paper. It does not appear, however, that M. Melloni had thought of applying his instrument to any question of polarization except that of tourmaline, and in a note he alludes to the objections which had been urged against Berard's conclusions, objections which he does not consider to have been overcome. — Ann. de Chmky Iv. 374. 2E2 212 Prof. Forbes on the Refraction a?id Polarization of Heat, 36. I fitted up two other bundles of mica- plates, in square pasteboard tubes of the kind described, which were marked E and F, the other plates being occasionally substituted, in order to verify the results, and to show that no accidental pe- culiarity of the plates could account for the differences ob- served. My experiments were usually made thus. The tube E was fixed to the pile ; the tube F, containing the other plate, had an index, which pointed to 0° when the two plates were parallel, to 90° when they were at right angles, &c. Five observations were taken ; at 0°, 90°, 180°, 270°, and again at 0°. The mean of the first and last were taken ; then the mean of this, and the indication at 180°, and the difference between this and the mean at 90° and 270°, was considered as the polarizing effect. An example will best illustrate this : — 1834, Nov. 26. — Brass heated hy Alcohol: 5^ inches from centre of Pile. Deviation. Analysing plate (E) at 0°; polarizing plate (F) at 0° . . 6J° 90 ..5i 180 ..7 270 . . 6 Mean at 0° . . . 6°'9 180° ... 7-0 Mean, 6 -91 Ratio 100 : 81, orl9 per cent. Mean at 90° and 270°, . . 5 '6 J polarized. The general concordance of these experiments will be gathered from the following list of results. 37. With non-luminous heat from ir EAD a paper, by Thomas Taylor, M.D.,F.L.S., entitled Jan. 20. — -IV '^ De Marchantieis.'' The author regards these plants as constituting from their higher development a distinct group from the HepaticfE, with which they have been hitherto associated. The paper contains a description of twelve species, distributed into the following genera, namely, 1. Marchantia, Linn., of which M. polymorpha is the type. 2. Fegatella, Caesalp. Raddi. Type of the genus M. conica, Linn. 3. LunuUiria, Micheli. Type of the genus M. crMcia^a, Linn. 4. Hygrophila. Type of tlie genus Marchantia irrigua, Wilson in Hooker's Brit. F!. ; a new species discovered by the author and Mr. William Wilson in various parts of Ireland. Royal Astronomical Society, 221 February 3. — Read ^' Observations on the Genus Ho.«ac/cia and the American Lot'i" By George Bentham, Esq., F.L.S. The author enumerates eleven species of this genus, the whole of which, except one from Mexico, are from California and the regions bordering on Columbia River, where they were discovered by Mr. Douglas. The Lotus sericeus of Pursh and several other species with solitary flowers, formerly referred by the author to Hosackia, he now considers as more naturally associating with Lotus than with that genus. His amended character of Hosackia is as follows: Calyx tu- bulosus vel subcampanulatus, 5-dentatus. Vexilli unguis a caeteris distans. AI(B vexillum subaequuntes, patenles. Carina submutica. Stylus subrectus. iS^igma capitatum. Legw^ncw cylindraceum,apterum. Herbae (boreali-americanae) perewwes? FoVm impari-pi?inata, Sti- pulae scariosce minutissimee, vel folioli diffortnes, Pedunculi axillares, umbellaiim pluriflori, folio Jlorali, seepius stipati. ROYAL ASTRONOMICAL SOCIETY. November 14, 1834". — The Society met this evening, for the first time, in its new apartments in Somerset House, which have recently been appropriated to it by His Majesty's Government, through the interference and at the request of His Royal Highness the Duke of Sussex. A vote of thanks was unanimously passed by the meeting, expres- sive of their sense of His Royal Highness's kind attention to the in- terests and welfare of the Society. The following communications were then read : — Some account of the Astronomical Observations made by Dr. Edmund Halley, at the Royal Observatory at Greenwich. By F. Baily, Esq., President of the Society. The author remarks, that although Dr. Halley was the Astrono- mer Royal for upwards of twenty years, yet that there are no ac-- counts published of any of his observations, except the relation of the three following phaenomena inserted in the Philosophical Transactions: viz. the solar eclipse on November 27, 1722; the transit of Mercury over the sun's disc on October 29, 1723 ; and the lunar eclipse on March 15, 1736. The rest exist in manuscript only, and have never yet been made public. They are contained in four small quarto volumes, deposited in the library of the Royal Observatory ; and it has been a frequent subject of inquiry, both at home and abroad, as to the contents of these volumes, and the value of the observations. These manuscripts are very badly, and sometimes rather con- fusedly written ; especially in the early part of the series : there being numerous computations and much extraneous matter written on the same page with the observations, intermixed with and occa- sionally obliterating the more important figures ; so that they can- not be so readily consulted with that ease and convenience, nor with that clearness and distinctness, which are desirable in works of this kind. Added to which, there is a constant risk of loss or damage by fire, or other accident, which ought not to exist in a document 22^ Royal Astronomical Society. of this importance. Under these circumstances, a representation of the case was laid before the Lords Commissioners of the Admi- ralty, who immediately ordered a fair copy of the observations to be made j and the same was by them presented to this Society in December 1832. It was in consequence of this gift that the author was induced to draw up the present memoir. Mr. Baily first gives an account of the number and state of the instruments at the Observatory, the clocks, &c.: and it appears that for four years, at least, after Dr. Halley was appointed to his situa- tion, he had only a 5>-feet transit instrument wherewith to carry on his observations. This is the first instrument of the kind erected there, and is described as " a curious telescopic instrument, fitted to an axis, and adjusted with screws to revolve in the plane of the Tneridian." It is evident, therefore, that Halley could at that period take nothing but transits. On the erection of the mural quadrant, however, in 1725, he was enabled also to take the zenith distances of the stars. He mnde observations likewise with two or three move- able telescopes with which he was furnished. And much confusion occurs, in the manuscript books, from the circumstance that the ob- servations with all these different instruments are recorded exactly alike, so that there is nothing to guide the reader as to xuhich instru- ment has been used in the observation. The state of his clocks also is represented as being very confused and irregular ; and the numerous stoppages they experienced, either in the act of being wound up, or from being suffered to run down, through absence or neglect, render it extremely difficult to deduce any very accurate results from the transit observations at such periods : an inconvenience which is felt, even to the very end of his labours. Dr. Halley 's observations were principally directed to the moon and planets : and with this object in view he usually observed such stars as were nearly on the same parallel of declination as those bodies, and differing from them very little in right ascension. Such observations therefore may, even now, be made available for deter- mining the positions of those moveable bodies at those periods, and thus tend to perfect their theory. But with respect to any accurate information relative to the absolute position of the fixed stars, the author considers that it would be difficult, if not impossible, to ob- tain it : and that the most that can be expected from the observa- tions would be the determination of the relative positions of some adjacent stars ; neither does he consider that the observed stars are in sufficient number to warrant the expense and trouble of attempt- ing such a measure. After entering into an explanation of these and other modes of observing adopted by Dr. Halley, the author proceeds to notice some of the most remarkable phaenomena recorded in the manuscript vo- lumes. He states, that although there are many observations of the superior planets, yet none of them are very near the time of their opposition to the sun. There are also several observations of Venus and Mercury; but not a single observation of the eclipses of Jupiter s Zoological Society, 223 satellites ; neither has he been able to find more than one double observation of Polaris^ above and below the pole, on the same day. There are eight occultations recorded ; together with five solar, and four lunar eclipses. And amongst the usual observations there are three transits of the two singular stars 36 Ophiuchi and 30 Scorpii, remarkable for their great proper motion — journeying together through space, although upwards of 13' distant from each other. Fiamsteed has only one observation of 30 Scorpii^ and Bradley did not observe it at all in right ascension. These observations, therefore, by Dr. Halley are so far interesting and satisfactory, that they con- firm the uniformity in the hiotion of the two stars. The non-publication of Halley 's observations seems to have ex- cited public notice even in his lifetime j and it appears that Sir Isaac Newton at length brought it under the notice of the Council of the Royal Society, who were at that time appointed to superintend such matters. Dr. Halley, who was present, excused himself by stating that, " there being many uses to be made of the said ob- servations for forming a method for better ascertaining the longitude of places, and a great reward being appointed by Act of Parliament for discovering such methods, he had hitherto kept his observations in his own custody, that he might have time to finish the theory he designs to build upon them, before others might take the advantage of reaping the benefit of his labours." It was remarkable that this was the last meeting of the Royal Society at which Newton was pre- sent, as he died eighteen days after, in the 85th year of his age. Mr. Baily closes his account by stating that the copy of the ob- servations presented to the Society by the Lords Commissioners of the Admiralty had been examined and compared with the original by Dr. Lee, the Treasurer, and Lieut. Raper, one of the Council of the Society: a laborious task which they have executed with great care and attention. In the execution of this troublesome under- taking they discovered numerous errors of the amanuensis, which have since been carefully corrected : so that there is now every reason to believe that the transcript is a faithful and accurate copy of the original. A short communication was read from Professor Schumacher to Mr. Baily, announcing that two comets had been discovered by a pupil of M. Dumouchel, of the Collegio Romano at Rome. *' As, however," it is observed in the Monthly Notices of the Society, " no very precise circumstances are given whereby the public might be enabled to judge of the reality of the discovery, it would not be fair to M. Dumouchel to make any formal announcement on the subject. Mr. Riddle communicated an account of a large meteor (appa- rently about the size of the moon) which was seen by Mr. Haggard, and Mr. Haggard, jun., at Blackheath, between twelve and one o'clock on the night of Wednesday, October 20. Mr. Haggard de- scribes it as resembling a ball from a Roman candle in colour. ZOOLOGICAL SOCIETY. September 9, 1834. — A letter was read, addressed to the Secretary l)y Dr. E. lliippcll, and dated Frankfort, August 10, 1834. It was 224? Zoological Society. accompanied by specimens of Magilus antiquus, Rupp., including both the shell and the animal, and of the shell and animal of a new genus of Pectinibranchiated Gasteropodous Mollusca. The latter was accompanied by a description by Dr. Riippell, who characterizes it, as follows, under the designation of Leptoconchus . Testa tenuis, pellucida, subglobosa, spird depress^, subobsoletd: aperturd magna, subovali, extremitatibus in contrarium versis, mar- ginibus baud coalitis, dextro tenui antic^ subexpanso : columelld nulls,, umbilico nullo, antice truncata, contorta. Afiimal proboscide elongato, retractili : tentaculis duobus, com- planatis, trigonis, interne ad basin coalitis, extern^ in medio oculos gerentibus : pede mediocri, operculo nullo : pallio ad marginem cir- culari, hand appendiculato, ad latus sinistrum subproducto : fora- mine branchiali submagno. The colour of the shell which constitutes the type of this new genus is constantly a slightly sordid milk-white. It is sulcated ex- ternally by numerous longitudinal undulated closely set lines, the outer whorls encroaching on the spire of the earlier ones so as almost to obliterate it. Length of the adult shell, 14^ lines; greatest breadth, 12-J-; length of the young shell, 74-; breadth, 6. Individuals of all ages have the shell thin and fragile, and con- stantly occur imbedded in the calcareous mass of polypes, having a communication with' the sea by only a moderate opening. They are found in the Red Sea, and are most frequently met with in Meandrina Phrygia. To distinguish the shell of Leptoconchus from that of Magilus it is sufficient to observe that in the latter the two margins of the aper- ture are always united, while in the former genus they are always disunited. The animals are distinguished by the possession and the want of an operculum, and by the difference in the proboscis ; the siphon of Magilus, moreover, does not occur in Leptoconchus. Dr. Riippell suggests that the systematic place which should be assigned to this genus is near the lanthince. The number of the tentacula, the oral proboscis, the mantle destitute of siphon, the pec- tinated branchiae composed of closely heaped pyramids, and the ab- sence of operculum, are so many marks of affinity ; to which may be added some of the characters of the shell : but he states himself to be perfectly aware that the difference between the habitations of these genera is so wide as to afford no confirmation of the correct- ness of this approximation. A letter was read, addressed to the Secretary by B. H. Hodgson, Esq., Corr. Memb. Z.S., and dated Nepal, March 4, 1834. It commences by remarking on the difficulty experienced by Zo- ologists in the determination of distinctive marks adequate for the separation of the genera Antilope, Capra, and Ovis; and then refers to the instances in which the writer has shown that the cha- racter of Antilope founded on the presumed absence of cavities in the cores of the horns connected with the frontal sinuses is incorrect. The value of the characters which are generally admitted by authors as distinguishing between the genera Capra and Ovis may, he con- Zoological Society. 225 ceives, be tested by a comparison of the wild race of either genus which belongs to the Himalaya. ** For the last year," Mr. Hodgson proceeds, ** I have had alive in my garden a splendid specimen of the mature male of each ; and I have frequently compared them together in all respects of manners and of structure. As the Goat in question, as well as the Sheep, is new, I will begin with a synoptical description of the two, and then proceed to notice the points of difference and of agreement existing between them. Tribe Caprid^, H. Smith. Genus Capra, Linn. Species Capra Jhdral. — The Jhdral of the Nepalese. " Affined to the Alpine jEgagri and to Capra Jemlaica. Adult male 50 inches long from snout to rump, and 33 high. Head finely formed and full of beauty and expression, clad in close short hair, and without the least vestige of a beard. Facial line straight. Ears small, narrow, erect, rounded at the tips, and striated. Eye lively. Between the nares a black moist skin. Nares themselves short and wide. Knees and sternum callous. Tail short, depressed, wholly nude below. Animal of compact powerful make, with a sparish, short, and bowed neck; deep barrel and chest; longish, very strong, and rigid limbs, supported on perpendicular pasterns, and high com- pact hoofs : false hoofs conic and considerably developed. Attitude of rest gathered and firm, with the head moderately raised, and the back sub-arched. Shoulders decidedly higher than the croup. Fore quarters superb, and wholly invested in a long, flowing, straight, lion-like mane, somewhat feathered vertically from the crown of the withers, and sweeping down below the knees. Hind quarters poor and porcine, much sloped off from the croup to the tail, and the skinmuch constricted between the hams behind. Fur of two sorts: the outer, hair of moderate harshness, neither wiry nor brittle, straight, and applied to the skin, but erigible under excitement, and of un- equal lengths and colours ; the inner, soft and woolly, as abundant as in the Wild Sheep and finer, of one length and colour. Horns 9 inches long, inserted obliquely on the crest of the frontals, and touching at the base with their anterior edges; subcompressed, subtriangular, and uniformly wrinkled across, except near the tips, where they are rounded and smooth, keeled and sharpened towards the points, obtusely rounded behind ; the edge of the keel neither nodose nor undulated, but smooth, or evanescently marked by the transverse wrinkles of the horns. The horns are divergent, simply recurved, and directed more upwards than backwards. " Colour of the animal a saturate brown superficially, but inter- nally hoary blue, and the mane, for the most part, wholly of that hue. Fore arms, lower part of hams, and backs of the legs, rusty. Entire fronts of the limbs, and whole face and cheeks, black-brown ; the dark colour on the two last parts divided by a longitudinal line of pale rufous ; and another before the eye, shorter. Lips and chin hoary, with a blackish patch on either side below the gape. Tip of tail and of ears blackish. Tongue and palate, and nude skin of lips Third Series. Vol. 6. No. 33. March 1835. 2 G 226 Zoological Society, and muzzle, black. Iris darkish red hazel. Odour very powerful in the mature male at certain times. •' Found in the wild state in the Kach^r region of Nepal, in small flocks or solitarily. Is bold, capricious, wanton, eminently scanso- rial, pugnacious, and easily tamed and acclimatised [acclimated] in foreign parts. " Remarks. Jhdral is closely affined by the character of the horns to the Alpine uEgagri, and still more nearly, in other respects, to Capra Jemlaica. It differs from the former by the less volume of the horns, by their smooth anterior edge, and by the absence of the beard ; from the latter, by the horns being much less compressed, not turned inwards at the points, nor nodose. Jhdral breeds with the domestic Goat, and more nearly resembles the ordinary types of the tame races than any wild species yet discovered. Genus Ovis, Linn. " Species Ovis Ndhoor, Mihi. — The Ndhobr of the Nepalese. New? Variety of Ovis Musmon } " Closely affined to Ovis Musmon, of which it is probably only a variety. Adult male 48 inches from snout to rump, and 32 high. Head coarse and expressionless, clad entirely in close short hair, without beard on the chin or throat, or any semblance of mane. Chaffron considerably arched. Ears medial, narrow, erect, pointed, striated. Eye dull. Moist space between the nares evanescent. Nares narrow and long. Knees and sternum callous. Tail medial, cylindrico- depressed, only half nude below. Structure moderately compact, not remarkable for power. Neck sparish, bowed, with a considerable dip from the crown of the shoulders. Limbs longish, firm, but slender, not remarkable for rigidity, and supported on lax pasterns, and on hoofs lower and less compact than the Goafs ; false hoofs mere callosities. Attitude of rest less gathered and firm, with the head lower, and the back straight. Shoulders decidedly lower than croup. Fore quarters not more massive than the hind, nor the extremities stronger. Fur of two sorts : the outer, hair of a harsh, brittle, quill-like character, serpentined internally, with the salient bows of one hair fitting into the resilient bends of another ; exter- nally straight, porrect from the skin, and very abundant ; of medial uniform length all over the body ; the inner coat, soft and woolly, rather spare, and not more abundant than in the Goat, Horns 22 inches along the curve, inserted high above the orbits on the crown of the forehead, touching nearly at the base with their whole depth, and carrying the frontal bones very high up between them, the pa- rietals being depressed in an equal degree*. The horns diverge greatly, but can scarcely be said to be spirally turned. They are first directed upwards considerably before the facial line, and then sweep downwards with a bold curve, the points again being recurved ♦ The Goat's skul! has the same form, but less strikingly developed ; and unless I am mistaken, this form of the skull would aftord a just and general mark to separate Ovis and Capra from Cervus and Antilope. There is a gradation of characters in this respect among the Antelopes tending to the Caprine type in their general structure. Zoological Society. 227 upwards and inwards. They are uncompressed, triangular, broadly convexed to the front, and cultrated to the back. ITieir anterior face is the widest, and is presented almost directly forwards : their lateral faces, which are rectilinear, have an oblique aspect, and unite in an acutish angle at the back. They are transversely wrinkled, except near the tips, which are round and smooth. " The colour of the animal is a pale slaty blue, obscured with earthy brown, in summer overlaid with a rufous tint. Head below, and inside of the limbs and hams, yellowish white. Edge of the buttocks behind and of the tail pure white. Face and fronts of the entire limbs and chest blackish. Bands on the flanks the same, and also the tip of the tail. Tongue and palate dark. Eye yellow hazel. No odour. " Is found in the wild state in the Kachar region of Nepal, north of the Jhdral, amid the glaciers of the Himalaya, and both on the Indian and Tibetan sides of the snowy crests of that range : is suf- ficiently bold and scandent, but far less pugnacious, capricious, and curious than the Jhdral. Much less easily acclimatised in foreign parts than he is, in confinement more resigned and apathetic, and has none of the JhdraVs propensity to bark trees vvdth his horns, and to feed upon that bark and upon young shoots and aromatic herbs. I have tried in vain to make the Ndhoor breed with tame Sheep ; be- cause he will not copulate with them. The female of the species has the chaiFron straight ; and the horns short, erect, subrecurved, and greatly depressed. The young want, at first, the marks on the limbs and flanks, and their nose is straight. •* Remarks. Differs from Ovis Musmon, to which it is closely allied, by the decided double flexure of the horns, their presence in the females, and the want of a tuft beneath the throat. " Having now completed the descriptions of the Wild Goat and the Wild Sheep, I shall proceed to the exhibition of the points of dif- ference and of resemblance between the two, beginning with the former. Goat. Sheep. Whole structure stronger and 1 , ° > Less so. more compact. J Limbs thicker and more rigid. Feebler and more slender. Hoofs higher and more compact. Lower and less so. False hoofs well developed. Evanescent. Head smaller and finer. Larger and heavier. Facial line straight. ChaiFron arched. Ears shorter and rounded. Longer and pointed. Tail short, flat, nude below. Longer, less depressed, and half nude only. Withers higher than croup. Croup higher. Fore legs stronger than hind. Fore and hind equal. Croup sloped off. Not so. Odorous. Not so. Nose moister, and nares short It • 4. i j , . , * ^ Less moist, longer, and nairower. 2 G 2 228 Zoological Society, Goat. Sheep. Horns of medial size, keeled, "I Horns very large, not keeled, and and turned upwards. j turned to the sides. Eye darker and keener. Paler and duller. Hair long and unequal. Short and equal. Back arched. Back straight. Bears change of climate well. Bears it ill. Is eminently curious, capricious, "1 , . . ^ ., j .• -j and confident. / ^' incurious, staid, and tiraid. Barkstrees with its horns, feed--) ^-^ ^ y. ^ ^ j • i ing on the peel, and on aro- I °'"\^!^°' A '; " '" matic herbs J addicted to aromatics. In fighting rears itself on its hind legs and lets the weight of its body fall on the adver- sary. In fighting runs a- tilt, adding the force of impulse to that of weight. The Goat and Sheep have in common, hair and wool; no beard; no suborbital sinuses ; evanescent muzzle; no inguinal pores ; horns in contact at the top of the head ; knees and sternum callous ; an- gular and transversely wrinkled horns ; striated ears ; two teats only in the females ; horns in both sexes ; and, lastly, incisors of precisely the same form. " Of the various diagnostics, then, proposed by Col. Hamilton Smith, it would seem that the following only can be perfectly relied on to separate Ovis from Capra : slender limbs ; longer pointed ears ; chafFron arched ; nares long and oblique ; very voluminous horns, turned laterally with double flexures. I should add myself, the strong and invariable distinction, — males not odorous, — as opposed to the males odorous of the genus Capra. But, after all, there are no physical distinctions at all equivalent to the moral ones so finely and truly delineated by Buffon, and which, notwithstanding what Col. H. Smith urges in favour of the courage and activity of Sheep, will, for ever, continue to be recognised as the only essential dia- gnostics of the two genera." September 23, 1834. — A letter was read, addressed to the Se- cretary by John Hearne, Esq., Corr. Memb. Z.S., and dated Port au Prince, July 16, 1834. It accompanied a present of " an Alligator from the river Artiboniti," which is referrible to the Crocodilus acutus, Cuv. ; and of some Doves. These are the little Ground Dove or Or- tolan of the English residents in Hayti, Columba passerina, Linn. ; and the red-legged Partridge, as it is called in that island, Col. mystacea, Temm. Mr. Hearne adverts to some other animals which he has observed in Hayti, and expresses his hopes of succeeding in bring- ing or sending them to England. The Secretary adverted to some other animals lately added to the Menagerie, and which he regarded as interesting either in a scien- tific point of view, or on account of their not having been previously contained in the collection. They included the silky Monkey, Midas Rosalia, Geoff., of which a specimen has recently been presented by T. Manton, Esq. ; the Javanese Ichneumon, Herpestes Javanicus, Zoological Society. 229 Geoff. ; the African Moufflon, Ovis Tragelaphus, Geoff., presented by Sir Thomas Reade, His Majesty's Consul- General at Tunis ; and a remarkably darkly coloured variety of the European Bear, Ursus Arctos, Linn., presented by R. H. Beaumont, Esq. Among the Birds there have been added a pair of the pied Pigeon of New Holland, Columba armillaris, Temm. ; a pair of the Caper- cailzie or Cock of the Woods, Tetrao Urogallus, Linn., obtained from Norway and presented to the Society by J. H. Pelly, jun., Esq. ; a pair of the Buffonian Touraco, Corythaix Buffonii, Le Vaill. ; and a specimen of the naked-legged Owl of the Indian Islands, Ketupa Ja- vanensis,Liess., (Strix Ketupu, Horsf.,) presented by James Harby, Esq., and stated to have been brought from Manilla. Among the Reptiles there have recently been added an interesting collection of Tortoises from China, presented by John Russel Reeves, Esq., of Canton, and including specimens of the three-banded Box- Tortoise, Cistuda trifasciata, Gray ; of Spengler's Terrapin, Geoemyda Spengleri, Gray, {Testudo Spengleri, Walh.); (see our last number, p. 152) ; of the Emi/s Sinensis, Em. Reevesii, and Em, Bealii, all lately described by Mr. Gray ; and also of the Platysternon megace- phalum. Gray. A Crocodile apparently referrible to the Crocodilus cataphractus, Cuv., is also at present living in the Menagerie: its nuchal plates constitute a series continuous with those of the back, but consist of only four rows instead of five, the number existing in the individual on which the species was originally founded. The specimen is stated to have been brought from Fernando Po. Mr. Ogilby called the attention of the Meeting to a specimen of an Irish Otter, which he at the same time presented to the Society in the name of Miss Anna Moody of the Roe Mills near Newtown Lemavaddy, by whom it was preserved and mounted. On ac- count of the intensity of its colouring, which approaches nearly to black both on the upper and under surface ; of the less extent of the pale colour beneath the throat as compared with the common Otter, Lutra vulgaris, Linn., as it exists in England ; and of some difference in the size of the ears and in the proportions of other parts ; Mr. Ogilby has long considered the Irish Otter as constitut- ing a distinct species ; and he feels strengthened in this view of the subject by the peculiarity of its habitation and manners. It is, in fact, to a considerable extent a marine animal, being found chiefly along the coast of the county of Antrim, living in hollows and caverns formed by the scattered masses of the basaltic columns of that coast, and constantly betaking itself to the sea when alarmed or hunted. It feeds chiefly on the salmon, and as it is consequently injurious to the fishery, a premium is paid for its destruction ; and there are many persons who make a profession of hunting it, earning a liveli- hood by the reward paid for it and by disposing of its skin. Mr. Ogilby stated his intention of comparing it minutely with the com- mon Otter as soon as he should be enabled to do so by the possession of entire subjects, and especially of attending to the comparison of the osteological structures. He added that he proposed to desig- nate it, provisionally, as the Lutra Roensis, in honour of the lady by whom it was presented. 2S0 Intelliiieiice and Miscellaneous Articles, 'to Mr. Owen read a " Description of a recent Clavagella," founded on the examination of an individual brought home by Mr. Cuming and imbedded in siliceous grit. The portion of rock contained the whole of the expanded cavity excavated for the abode of the animal, to- gether with the fixed valve of its shell and about an inch of its cal- careous tube : the loose smaller valve was detached from the soft parts. Mr. Owen describes in detail the fixed valve, which cor- responds to the left side of the animal's body ; the attachment to it of the adductor muscles, two in number ; its passage into the cal- careous tube by a continuance of the shelly substance ; the tube it- self, which communicates with the posterior part of the chamber next the side which corresponds with the ventral surface of the ani- mal ; and the free valve. He regards it as probable that the animal of this species, having penetrated into the rock for a certain distance, then becomes stationary, and limits its operations to enlarging its chamber to the extent required for the development of its ovary : this enlargement takes place in the dorsal, dextral, and anterior directions. The soft parts of Clavagella form an irregularly quadrate mass, convex anteriorly, rather flattened at the sides, and slightly naiTow- ing towards the posterior end, from which the smooth rounded si- phon is continued. This contains the anal and branchial canals, which are separated by a strong muscular septum, but do not pro- ject as distinct tubes : in this respect Clavagella agrees with Gastro- chccna and Aspergillum. The mantle is a closed sac, having only an opening for the passage of the siphon and a small slit at the opposite end for the passage of a rudimentary foot : the use of this slit in Clavagella is obviously different from that assigned by M. Riippell to the corresponding structure in Aspergillum. Mr. Owen describes the mantle and its structure ; the siphon ; and the thick mass of muscular fibres at the anterior part of the mantle, which forms probably one of the principal instruments in the work of excavation : he also notices the great development, as com- pared with the size of the animal, of the adductor muscles. He then proceeds to the viscera, which generally agree with the typical structure in other Bivalves. The digestive system, which accords with that which is usual in Acephalous Mollusca, is described; as are also the respiratory and circulating systems, the principal ner- vous ganglia, and the ovary. The paper was accompanied by drawings illustrative of the several structures described in it. The specimen described belongs to the species termed by Mr. Broderip Clavagella lata. XXXIX. Intelligence and Miscellaneous Articles, MR. STURGEON ON AN AURORA BOREALIS SEEN AT WOOLWICH, ON DECEMBER 22, 1834. A BEAUTIFUL Aurora Borealis was seen from this place last night. I was on Woolwich Common when I first saw it, then ex- Intelligence and Miscellaneous Articles, 231 actly six o'clock. It consisted of several groups of vertical beams of pale yellowish light on both sides of the north star, extending nearly to equal distances in the western and eastern directions. These beams presented the strongest light at their bases, and grew gra- dually fainter, to their superior extremities, where they softened and gently glided into the most attenuated light, and were lost at various altitudes, some of which were near to the zenith. These streamers soon faded, and gave place to a few straggling vertical coruscations, displayed in various parts of the northern sky, which in their turn were again succeeded by the finest streamers I ever beheld. It was now five minutes past six. These splendid streamers were of the same tint as the former, and extended from the black nucleus near the horizon to the zenith in nearly the same manner ; but the refulgence of these far exceeded that of the former. These streamers consisted principally of two parallel groups, one on each side of the north, and with some considerable distance between them. Smaller streamers were, however, playing in the intermediate space, and also on their outer horizontal skirts. The horizontal boundaries of the aurora, at this time, seemed to be the Milky Way on the west, and near to the planet Mars on the east. From this time the aurora gradually diminished in splendour, and about seven was nearly lost ; it occasionally, however, brightened with a few faint flashing momentary streamers till between ten and eleven, at which time I discontinued my observations. During the display of the fine streamers, which first presented themselves about five minutes past six, I hurried home to adjust a magnetic needle. It was about half-past six before I had my mag- netic apparatus fit for observation, and the splendour of the aurora had now passed its meridian. I diligently watched the needle and the aurora till half-past ten, but observed nothing in the motions of the former that could possibly be attributed to the influence of the latter. From the brilliancy of the aurora at six o'clock, I imagine that it was exhibited at a much earlier period of the evening, but I have had no opportunity of ascertaining the fact from persons likely to have seen it. I think it is likely that the aurora was very fine in Scot- land, and perhaps in higher north latitudes, after seven o'clock, perhaps till nine or ten. Artillery Place. Woolwich, Dec. 23, 1834. W. Sturgeon. P.S. This aurora appeared to have no particular respect for the magnetic north : it was nearly, if not exactly, bisected by the true meridian during the whole of the time 1 observed it. MR. GILL ON THE STRUCTURE OF THE FIBRES OF FLAX AND COTTON, IN REFERENCE TO THE OBSERVATIONS OF MR, BAUER. To the Editors of the Philosophical Magazine and Journal of Science, Gentlemen, 1 felt myself much interested in the perusal of a late article in your valuable work, by Mr. Thomson, on the Mummy Cloth ; 232 Litellisence and Miscellaneous Articles* -to proving, by Mr. Bauer's microscopic delineations, that, instead of it being made of cotton, it is, in fact, linen. I had long employed the microscope for the purpose of distinguishing the difference be- tween linen and cotton, and in most of the statements I concur. I must, however, disagree with Mr. Bauer on the point that the fibres of flax are cellular ; on the contrary, when they are perfectly freed from the cross fibres by which they are held together in their natu- ral state, (which was most completely effected by the late Mr. Lee), they are each found to be composed of one undivided cylin- drical fibre, extending from the root to where they are united to the leaves of the plant. I have specimens of flax so treated by Mr. Lee, and which, from their beautiful glossiness, have frequently been mistaken for silk. 1 have not found that the flat fibres of cotton are uniformly txi'istedy but only occasionally so, and in different degrees ; in fact, many are not twisted at all. T am glad that the microscope is at length likely to find its due estimation j and hope it will now be more frequently employed in showing us things as they really are. I am. Gentlemen, With much respect, your most obedient servant. Savoy Depot of Practical Science, Thomas Gill, 125, Central Strand, London, Jan. 16, 1835. Advising Engineer. ON PROFESSOR MITCHELL S METHOD OF PREPARING CARBONIC OXIDE. BY DR. GALE. In vol. v., p. 391, of the London and Edinburgh Philosophical Magazine, we have inserted Dr. Mitchell's method of preparing carbonic oxide free from carbonic acid. We have since found that several of Dr. M.'s statements are erroneous, and intended to have noticed them ; instead of this we copy the following observations by Dr. Gale, Professor of Chemistry in New York, contained in Silliman's Journal for October last. *< Having received No. 2. of Vol. XXV.of this Journal, containing Professor Mitchell's paper on a new process for preparing carbonic oxide, about the time I was to lecture on that subject before my class in the College of Pharmacy, I adopted Prof. M.'s plan, and fol- lowed his directions as nearly as possible, but much to my discom- fiture found the gas obtained was perfectly incombustible : but I should here state, that it was used immediately after preparation. As gases will sometimes burn from a large orifice when they will not from a smaller one, I varied the size of the aperture, but all to no purpose. I then collected more gas, with * heat duly moderated,' and preserved only the first and last portions, but did not succeed in causing it to burn from an orifice. I then threw up, by means of a syringe, some caustic potash into the receiver containing the gas; a rapid absorption took place, amounting to nearly half the original quantity, and the remainder was sufficiently pure carbonic oxide. 1 also ascertained, that if the gas, when procured, be allowed to stand over cold water, and especially in broad and shallow receivers, for two or three hours, so much of the carbonic acid is absorbed Intelligence and Miscellaneous Articles, 233; ihat the remaining gas will burn with its ordinary appearance. The same remark will apply to carbonic oxide prepared by any of the ordinary methods described in the books. Indeed, I am constantly in the habit of preparing the gas in the morning, when it is to be used in the afternoon, and thus avoid the occasion of using any alkali. " Although from the above experiments I was quite satisfied that carbonic acid is always produced in the above-mentioned experi- ments, yet, that I might be able to speak with perfect confidence, I was induced to make a complete analysis of the gas obtained after Dr. Mitchell's plan. Taking a given weight of the oxalate of am- monia, and the proportion directed of sulphuric acid, I collected the whole gas evolved from the materials over mercury, that none should be absorbed during the operation. One hundred equal parts having been set aside for examination, pure liquid potassa was thrown up by means of a syringe, and the vessel agitated until no more absorp- tion took place, when fifty parts of the gas had disappeared. The residual gas, on being detonated with oxygen, was found to be nearly pure carbonic oxide. In order to ascertain whether the gas dif- fered in its qualities at different stages of the process, I collected portions of it at regular intervals, throughout the operation, and subjected them to careful examination. The result of these expe- riments was pretty uniform, not varying in any case two per cent, from fifty measures of each gas ; and hence I infer, that the oxalate of ammonia, treated as above, for obtaining carbonic oxide, yields the same products as the binoxalate of potassa or oxalic acid, treated according to the methods described in the books. "Professor Mitchell states, that ' on examining the residuary mat- ter left in the retort, it is found to be strong sulphuric acid.' I must confess, 1 am at a loss to know in what way he made an ex- amination, to arrive at such a conclusion, unless it be that he used more than ' one or two drachms of sulphuric acid,' for in each case in which I examined the residue, where an ounce of the oxalate and two drachms of acid were used, I found crystals in the retort, after the materials had cooled, answering in every respect to the acid sulphate of ammonia. If the quantity of sulphuric acid be increased to four or five drachms, and the heat be stopped a little before the gas ceases to come over, the acid will then hold the sulphate in solu- tion and exhibit to the eye an appearance of sulphuric acid j but a single and very simple experiment, namely, the evaporation of a few drops of the liquid on a platinum or glass capsule, until a part of the acid is expelled, will indicate the presence of some salt, and that, on examination, will be found as above mentioned. That am- monia should escape from the retort, in a free state, while it is in contact with a large excess of free sulphuric acid, and then combine with the carbonic acid resulting from the decomposition of the oxalic acid, appears to me unphilosophical, and is disproved by experi- ment, for we recover the whole, or very nearly all the ammonia in combination with sulphuric acid." Third Series. Vol. 6. No. 33. March 1835. 2 H 2S4« Intelligence afid Miscellaneous Articles. CARBONATE OF STRONTIA DISCOVERED IN THE UNITED STATES. The following letter on this subject is contained in Silliman's Journal tor October last. *' I embrace an early opportunity of stating, through the medium of the Journal of Science, the discovery of the carbonate of strontia in this country. So far as my knowledge extends, this mineral has not, until the present time, been observed in the limits of the United States, and it is even considered rare in Europe. This fact makes it peculiarly interesting to our mineralogists. Perhaps I ought to make a reserve in pronouncing it pure carbonate of strontia, as the mineral may contain other elements besides carbonic acid and strontia. The following are some of its most interesting characters. ** Colour, nearly pure white; sometimes tinged yellowish on the surface. Lustre, vitreous ■ fibrous varieties, pearly. Translucent. . . opake. Brittle, and easily reduced to a powder. Hardness = 35, of the scale of Mohs. Specific gravity, undetermined. Streak, white. Cleavage, apparently parallel to the plane of a rhombic prism. The crystallization is too imperfect to admit of measurement. " Before the blowpipe it is infusible, but with a strong heat an im- perfectly friable, white mass is formed, which has an acrid alkaline taste. Colour of the flame, red or reddish purple. " In muriatic acid it dissolves, with an active effervescence, accom- panied with the disengagement of carbonic acid. Solution incom- plete in cold muriatic acid. The muriatic solution, on the addition of alcohol, burns with a fine carmine red flame. From this solution sulphuric acid throws down a white precipitate. " The varieties of this substance are mostly compound. The most perfect consist of stellated groups, or rather of imperfect individuals diverging from several centres, forming masses of diflPerent sizes. On one partially decomposed specimen, I observed a few small but regular six-sided prisms. In all other cases, the crystallization is too confused to permit the determination of the precise forms, or their dimensions. Some pieces, which evidently contain carbonate of strontia, resemble, externally, its congener, the sulphate ; that is, they are tinged bluish, and present a structure both laminated and fibrous. " I conjecture that some of the specimens are the baro-strontianite of Traill. Others seem to be strontia, combined with carbonate of lime. " The locality of this mineral, or family of minerals, is Scoharie, New York, in the vicinity of Ball's Cave, which has already fur- nished so many fine things for our cabinets. " I hope, erelong, to furnish a more particular account of the va- rieties mentioned in this communication. *• William's College, Aug. 15, 1834. Ebenezer Emmons." SEPARATION OF SOME METALLIC OXIDES. M. Person proposes to separate the oxides of cobalt and nickel ia the following manner : Paraphosphoric acid is to be added to a Intell'mence and Miscellaneous Articles, 235 "G nitric or muriatic solution of these oxides sufficient to saturate them ; ammonia is to be poured into the solution, which occasions a pre- cipitate, which is redissolved by excess of ammonia. The liquor assumes a greyish blue or violet tint, according to the proportions of the two oxides. Exposed to the air in an open vessel, this solution loses the excess of ammonia, and becomes turbid. The deposit formed consists of a double paraphosphate of nickel and ammonia, at first of a greyish colour, and then of a fine green. When the li- quor becomes clear, the solution is of a fine rose colour. If it con- tains no nickel, it may be evaporated without becoming turbid, to the consistence of a syrup. The two salts being thus isolated, the paraphosphoric acid is to be separated either by the hydrosulphuret of ammonia or by carbonate of soda. SEPARATION OF OXIDE OF CADMIUM AND OXIDE OF BISMUTH. Paraphosphate of bismuth is insoluble in solution of ammonia, while paraphosphate of cadmium dissolves readily in it as long as there is excess of ammonia. If, then, these two oxides are dissolved by nitric acid and paraphosphoric acid be poured into the solution, all the bismuth is precipitated. After having washed the precipitate with solution of ammonia, all the cadmium will be removed j and it only remains to separate the oxides from the paraphosphoric acid. This method may also be applied to the separation of the oxides of lead and mercury, the latter forming a soluble salt with the para- phosphoric acid and ammonia, whilst the oxide of lead forms an in- soluble one. The paraphosphoric acid employed by M. Person is obtained by calcining pure phosphate of ammonia. Separation of oxide of uranium from the oxides of cobalt, nickel^ and zinc. — Oxide of uranium may be completely separated from these three oxides, by using subacetate of lead; for a solution of this salt poured into a solution of nitrate of uranium, cobalt, nickel, and zinc, forms a precipitate of uranate of lead, which is completely in- soluble in excess of a solution of subacetate of lead j whereas, under the same circumstances, the insoluble compounds of oxide of cobalt, of nickel, and of zinc with lead, dissolve very readily in excess of the subacetate. It was in this way that Mr. Person discovered cobalt in combination with uranium, under circumstances in which other methods would be unavailable. — Ann, de Chim. et de Phys,y t. Ivi. p. 333. ACTION OF MURIATE OF AMMONIA ON CERTAIN SULPHATES. M. Vogel finds when equal bulks of strong solutions of muriate of ammonia and protosulphate of iron are mixed, small transparent crystals of a bright yellow colour are formed in twenty-four hours. These crystals are very hard, and much less soluble in water than sulphate of iron. When these crystals are heated by a spirit-lamp in a glass, they swell a little without fusing ; they become of a dull white and opake ; water evaporates, and afterwards ammonia and sulphate of ammonia. 2H2 236 Intelligence and Miscellaneous Articles. •^to When strong sulphuric acid is poured upon these crystals, they yield water to it and become opake, without effervescing. The aqueous solution of these crystals is colourless, and contains protoxide of iron. Nitrate of silver does not throw down any chlo- ride ; but after some time metallic silver is precipitated. '1 here is therefore no muriatic acid in these crystals, and they act like sul- phate of iron and ammonia. As these crystals contain no muriatic acid, the question is, What has become of that portion which the muriate of ammonia contained ? This acid was not expelled, and the mother-water did not redden litmus paper more than the sulphate would have done; nor was any muriate of iron formed; but rather a double salt, in which muriatic acid was neutralized by ammonia and by protoxide of iron; and this salt crystallizes by evaporation in transparent very hard octahedrons of a yellow colour. This salt is not deliquescent, and when sul- phuric acid is added to it, muriatic acid gas is evolved. When heated in a glass tube, muriate of ammonia sublimes, and oxide of iron re- mains. It is very soluble in water, but insoluble in alcohol, and consists of a neutral combination of muriatic acid, oxide of iron, and ammonia. The solution of sulphate of copper becomes green when mixed with one of muriate of ammonia, in equal volumes, in a close ves- sel, and in half an hour a bluish white salt is formed, and in twenty- four hours the crystals increase considerably in volume. They are transparent, but lose this transparency and their water of crystalli- zation in dry air. Sulphuric acid occasions no effervescence in them, nor does nitrate of silver render a solution turbid; they therefore contain no muriatic acid: they are soluble in one part and a half of boiling water, and the solution crystallizes on cooling. They have the properties of a neutral compound of sulphuric acid, peroxide of copper, and ammonia. The mother-water decanted and eva- porated gives crystals of a bright green, which are unalterable in the air ; they consist of muriatic acid, neutralized with oxide of copper and ammonia. The mixed concentrated solutions of sulphate of manganese and muriate of ammonia, give no crystals after several days, but by evaporation crystals are obtained on cooling. These crystals are not like either sulphate of manganese or muriate of ammonia ; they are hard, of a clear yellowish white, and contain no muriatic acid, At between 140° and 158° Fahr.they lose their water of crystalliza- tion and become opake : when heated in a glass tube, water and sulphate of ammonia are volatilized. It appears, then, that the sulphates mentioned are not completely decomposed by muriate of ammonia, but only in part. Water, containing common salt or muriate of ammonia, dissolves a much larger quantity of sulphate of lime than pure water ; but this salt is not decomposed, for by evaporation and heat, muriate of ammonia sublimed, leaving sulphate of lime unmixed with muriate. When a very dilute solution of muriate of ammonia is left for a few minutes in contact with sulphate of lead, it is found to contain Intelligence and Miscellaneous Articles. ,237 a notaWe quantity of the metallic oxide. If a solution of muriate of ammonia is boiled with sulphate of lead, and the liquor be filtered while boiling, crystals of chloride of lead are formed, and the solu- tion contains sulphate of ammonia: when the sulphate is repeatedly boiled in fresh portions of solution of muriate of ammonia, the sul- phate of lead is eventually perfectly decomposed. Sulphate of lead is slightly soluble in water, for sulphuretted hydrogen and nitrate of barytes both occasion precipitation in it.— Journal de Pharmacie, September 1834. PEROXIDE OF IRON AS AN ANTIDOTE TO ARSENIOUS ACID, The following letter, addressed by Dr. Bunson to M. Poggen- dorft', is translated from the Journal de Pharmacie for October last. Gottingen, May 1, 1834. It is long since I observed, that a solution of arsenious acid is so completely precipitated by pure hydrate of iron recently preci- pitated, and suspended in water, that a current of sulphuretted hy- drogen gas passed into the liquor after filtration, and the addition of a small quantity of muriatic acid, does not indicate the presence of the smallest portion of arsenious acid. 1 have also found, that if a few drops of ammonia be added to this substance, and it be digested in a gentle heat, with arsenious acid reduced to fine powder, a subperarsenite of iron, which is per- fectly insoluble, is quickly formed. A series of experiments, foun- ded upon this observation, has firmly persuaded me that this sub- stance combines the most favourable properties for serving as an antidote to arsenious acid, both solid and in solution. Dr. Berthold consented, at my request, to assist me in examining this subject in all its bearings, and to submit it to the most rigorous experiments. The results of this examination have much exceeded our expecta- tion, and have confirmed us in the persuasion that perhydrate of iron is a better antidote for arsenious acid, both solid and in solu- tion, than albumen is for corrosive sublimate. Two young dogs, scarcely 12 inches high, had four to eight grains of arsenious acid given to them in fine powder, and the oesophagus was tied to prevent vomiting ; they lived more than a week without ex- hibiting the slightest symptoms of poisoning by arsenic, either du- ring lite or on examination after death. The excrements voided were in very small quantity, for the animals were deprived of food and drink, and they contained almost the whole of the poisonous sub- stance in the state of subperarsenite of iron. We satisfied ourselves, by experiments upon animals, that a quan- tity of perhydrate of iron, equal to four or six drams of the peroxide of this metal, with sixteen drops of ammonia, is sufficient to trans- form in the stomach eight or ten grains of well-pulverized arsenious acid into insoluble arsenite. It is besides easy to see, that in cases of poisoning by arsenic, this substance, with or without ammonia, may be exhibited in much larger quantity, either by the mouth or as an enema ; for the perhydrate of iron being a body totally inso- 2 38 Intelligence and Miscellaneous Articles, luble in it, exerts no action on the animal coconomy. — Journal de Pharmacies October 1834. IMPROVED COMPASS-NEEDLES. We are informed by a correspondent that Dr. M. Smith of Wash- ington, United States, has effected a great improvement in the ma- nufacture of magnetic needles for the compass. He has succeeded, it is stated to us, in producing a needle, which in the same place uniformly settles itself upon the same magnetic meridian ; and all the needles which he prepares take the same line of direction. They appear to have more directive force, are less susceptible of local disturbance, and are more permanent in their properties than the common needles of ships' compavsses. Seamen who have used them say that they are more steady in squally weather than those which they have been accustomed to employ. Dr.Smith*sneedles,we are further informed, have been examined by the officers of the naval department of the United States, who, after verifying their indications and trying them at sea, have concurred in a favourable report of their qualities. Dr. Smith will be happy to submit his needles to the inspection or examination of all persons who may be interested in the subject, upon their addressing a note to him, at the Museum of National Manufactures, Leicester-square. ANALYSES OF OSMIRIDIUM AND ALLANITE. The six-sided grains of osmiridium from Nischne-Tagilsk and Ekaterinenburg, described by Professor Gustav Rose, consist, ac- cording to Berzelius {Konig. Vetejish. Acad. Handling. 1833), of 25 iridium and 75 osmium. Their composition is consequently expressed by the symbol I-f-30s. A specimen of allanite from Iglorsoit in Greenland, the specific gravity of which was 3'44;92, has lately been analysed by Stro- meyer: 100 parts gave Silex 33021 Alumina 15-226 Protoxide of cerium 21 -600 Protoxide of iron 15-101 Protoxide of manganese 0*404 Lime 11-080 Water 3000 99-432 It gelatinizes readily in nitric and muriatic acid. SCIENTIFIC BOOK. Preparing for Publication. By Prof. Phillips. The Second Volume of Illustrations of the Geology of Yorkshire, with numerous Maps, Sections, and Plates of Organic Remains. Also a new edition of the First Volume of that work. Intelligence and Miscellaneous Articles. 239 OBSERVATIONS ON MR. STURGEON's LETTER CONTAINED IN THE LOND. AND EDINB. PHIL. MAG. FOR NOVEMBER 1834. BY MR. FRANCIS WATKINS. To Richard Phillipsy Esq., F.R,S,y Sfc. My dear Sir, On looking over your valuable Journal for the last year, I was somewhat surprised to find in the November Number a letter from Mr. Sturgeon detailing the results of some experiments which he made in magneto-electricity the 28th of August 1834, with the large steel magnet belonging to the proprietors of the Gallery of Practi- cal Science, Adelaide Street, Strand. I take the liberty of calling your attention to the fact, that many months previously to the date of Mr. Sturgeon's experiments, (namely, on the evening of the 14th of November 1833,) I had the pleasure conjointly with Mr. Saxton (the projector and maker of the large and splendid magnet exhibited in Adelaide Street,) of il- lustrating in the presence of yourself, Messrs. Faraday, Lardner, Turner, Daniell, Cooper, Moseley, Pepys, and a host of other sci- entific gentlemen assembled at the Gallery, the mechanical, physi- cal, and chemical effects of electricity developed by steel magnets. You will, no doubt, recollect that on the evening in question I superintended a large magnetic machine which was very kindly lent at my solicitation by the Count de Predevalle, and constructed for that nobleman by the ingenious artist M. Pixii of Paris, while on the same evening Mr. Saxton displayed the splendid powers of the instrument contrived and made by himself. There is nothing in these observations intended to underrate the merits of Mr. Sturgeon; indeed, I feel assured, had that gentleman been aware of what had been already done, he would not have for- warded his letter for insertion in your Magazine. Mr. Sturgeon I well know to be an ardent and zealous labourer in the field of physical science, and 1 hope you will allow me here to record, that I have received many friendly and valuable hints from that gentle- man. Yet in justice to Mr. Saxton and myself, I could not let the opportunity pass of bringing to your recollection what had been achieved and experimentally illustrated months before the date of Mr. Sturgeon's experiments. Should you consider it worth while to insert these remarks in your Miscellany, your readers will be apprised that what Mr. Stur* geon brings forward as new in magneto-electricity in August 1834, had been noticed by Mr, Saxton, myself, and others, many months previously. And it ma}'' here be observed, that notices of polar de- composition by magneto-electric agency were published in some French journals about the latter end of the year 1832. I remain, my dear Sir, yours faithfully, 5, Charing Cross, Jan. 22, 1835. Francis Watkins. 4» >^i; 41 ^ ex « S^-g ra ITT S "J -«5 cu^ 2 2^^ § ^6 '^. S 3 3 O O o5 ^ •■ wns '^ M s-^ E5 Si b:. .0 >.' u . be h-ji: XuS 0) 4,%. »o O) e <^^ M OJ.S ^^o^Stf £;S \- . rt lO 05 lO 0> rt rl p^ lo o5 isog I : .00 <0 . U3 t^ . •puo'i •?sog : :§ : : t^ 6 • J J s J J J J J j_s , E J a ss^-jjjjj ■■J u ou^ooooo c« rt i> •puoq ^ H H W ^ ^ ^' ,^ S:' •KTfg nsog 'COIN CI f*5co(N (N cococofOrt<"^^"^c:;cN cjco.iccooicir^i>.com-^Mtr5mc^ooioc GO ■^rfc»^c^o^oc^a^o O'*'^O00^OOI>.t>-'-'00OJt^C0u:>"^'>!ffO ir^ '^* ^a iS^ trt nri nri (-^\ i r\ ^-« ir-i ^— s if-s r^ .^ nri ^ #ni ^m .^ ^^ r^\ -^^ tm — ^ r*> (^ 00 < (N «N — CI CO ic»t-^vo(OTtoovo«o_ „_...,._ t-.-.-t-. t - '6o6666o6^6^6^c^6^a^o^a^6^6^c^a^666c)6666666 lC0C0C0C0C0C0C0OMC<0 Rossal Landmark and Farleton Knot. 47° 47' 8" by multiple of 5 9-5 \o 7-5 16 7-5 20 256 Mr. J. Nixon on the Trigonometrical Height N.B. Angles by the circle are marked C, and those on the repeating principle by the theodolite T, the figures af- fixed denoting the multiple of repetition. Horizontal angles by the theodolite are marked t, with the number of observa- tions affixed. The figure is omitted when the angle has been obtained merely by the addition or difference of other angles. The difference between 180° and the sum of the observed angles of a triangle is given within brackets. The rational mean of a distance derived from different bases is stated the last column. in In 44. 32 29 Tower ; C Cl3 97203-0 97198-lft. 24576-2 24570-8 XIII. Ingleborough Warton Crair Lancaster Church 21 8 47 C13 0 97201-3 03 47 0 55 4 13 36105-3 97198-1 36104-8 XIV. Warton Crag Clougha Pike Lancaster Church 31 4 7 C 12 36104-4 49 18 47 C 15 24571-6 ' 99 37 6 0 36104-8 24570-8 XV. ' Ingleborough 41 0 26 C 13 97197-5 97198-1 Farleton Knot 94 48 7 C 16 64001-2 64001-6 Lancaster Church 44 11 27 0 XVL Farleton Knot i 21 Clouorha Pike 70 9 26| 6 13 Lancaster Church | 88 44 20^ c C 16 0 64002-0 24566-7 64001-6 24570-8 XVII. Ingleborough 34 4 11 C 10 97192-0 97198-1 Hutton Roof Moor 109 14 3i Cl4 57666-0 57668-4 Lancaster Church 36 41 45^ 0 xvin. Hutton Roof Moor Clougha Pike 74 30 56, C 15 Lancaster Church* 81 14 31^1 0 24 14 321 C 13 57670-1 57668-4 24571-1 24570-8 XIX. [-18M Ingleborough 19 51 46 c (67990-3 679900) W^arton Crag 51 54 28 C 11 29352-5 29352-7 Farleton Knot 108 13 46 TlO * The distance from L 78 57 3U C 14 Bridge N.W. | of Aqueduct.. .J With the included angle at Clougha Pike 105^ 57' 1", and the sides 24885 and 81529-8, we get 91550 feet, the distance from Ingleborough to the Bridge. C6 0 24885 7447 24821-5 7421- XXIV. Clougha Pike 17 16 211 C 6 Lancaster Church 83 16 38 0 Aqueduct Bank... 79 27 0^ C 14 . With the included angle at Clougha Pike 105° 58' 46", and the sides 24821-5 and 81529-8, we have 91528-4, the di- stance from Ingleborough to the Aqueduct Bank. the same stations, will be, respectively, 131629, 131631, 131629; mean 131629-6 feet. The (observed) included angle at Ingleborough and the sides 97198-1 and 77614-5 feet form the following triangle: The Calf 47° 7' 27" — 131629 feet. Ingleborough 97 3 38 — 97198 — Lancaster Church... 35 48 53 According to Mudge, the errors of these angles will be +18", +9, and —27". The excess of the first distance is 231 feet, and that of the second 24 feet. 2 L 2 260 Mr. J. Nixon on the Trigonometrical Height XXV. Clougha Pike Warton Crag Hest Breakwater 1 Pole / 24° 40' 25'' 45 30 35^ 109 48 59J C21 C 15 35596-4 20830-2 C 10 35593'8ft. XXVI. I Clougha Pike I 45 28 7 Farleton Knot | 30 29 34 Hest Breakwater l Pole / 104 2 18^ Cl7 C14 35593-0 50003-0 0 35593*8 XXVII. Clougha Pike Hutton Roof Moor Breakwater Pole... r+191"] 49 52 54 36 55 50i 93 11 15^ C 19 C17 C 12 35592-0 35593-8 45299-0 I XXVIII. W^arton Crag Hest Breakwater 1 Pole / Hest Wall [ -j- 39" (divided between the two greater angles)j 4 59 52 C 17 22222-0 124 2 48 t 5 2336-5t 50 57 20 t 3 » f 2339-3 by the base on Hest Sands. (See vol. v. page 267.) XXIX. Clougha Pike.. Farleton Knot. Black Comb.... 56 53 41 C&T 158949-5 98 1 22 T8 134463-0* 25 4 57 0 1 (See Trian- leXI.) * With the included angle 5° 23' 20" at Ingleborough, and the sides 67999 and 201970, we have 134458-4 feet for the same distance. With the included angle 1° 23' 56" at Ingleborough, and the sides 61512*5 and 201970, we get 140482 feet for the di- stance from Hutton Roof Moor to Black Comb. With the included angle 145° 8' 20" at Warton Crag, and the sides 22222 and 26031-8, we get 46052 feet for the di- stance from Hest Wall to Hutton Roof Moor. With the included angle l65° 7' 58" at Warton Crag, and the sides 22222 and 29352-7, we have 51149 feet for the di- stance from Hest Wall to Farleton Knot. With the included angle at Hutton Roof Moor 90^ 30' 22"? and the sides 365 and 101 55 4, we get 10165 feet for the di- stance from Farleton Knot to the highest point of Hutton Roof Moor. of Ingleborough above the Level of the Sea, "261 Bearings from the Station on Ingleborough, Boulsworth Hill 153°53' 40" Clougha West Pike 232 14 47 Rossal Landmark 237 40 S5 Lancaster Church 244 27 13 Aqueduct Station 247 21 32 Aqueduct Bridge 247 23 48 Warton Crag 265 36 4 Hutton Roof Moor ^278 31 20 Black Comb 279 55 19 Farleton Knot 285 27 39 The Calf 341 30 51 Centre of the Tower 264 40 9 *** South = 180°; West, 270°; North, 360°; East, 90°. Remarks. — In the triangles L to VL the distances to Ingle- borough derived from the first base line agree to a foot with those obtained by the second, and give the distance from the Calf to Rossal Landmark (nearly 38 miles,) equally correct. With regard to the distance to Lancaster Church tower, of which my measurement appears to be 24 feet in excess, it may be viewed either as a base of verification, proving my distances to be in excess at the rate of 1 in 4000 ; or, if my signal is placed 5 feet too much to the northward, and the Colonel has observed the north-east angle of the church tower, then will the error be reduced to 3| feet*. [To be continued.] * In the course of the operations the following distances were ob- tained from horizontal anglesl by the theodolite : ! „ . ,J Feet. Clougha Pike .... 84 40 55 Farleton Knot .... 60 23 29 Walney Lighthouse. I CloughTPike .... ,63 53 37 Warton Crag .... 89 5 46 Walney Lighthouse. Clougha Pike . , Farleton Knot . Highest S. turret of\ PeelCastle. \ Clougha Pike Warton Crag Peel Castle. 81 55 \i5 62 16 12 61 7 58 91 45 7 Warton Crag .... HestWall S.E. angle of Ulver- ston Church Tower. 87 4 0 74 54 48 103,336 118,345 103,354 92,821 102,947 115,151 102,948 90,199 Warton Crag. ..., Breakwater Pole . , Ulverston Church. Warton Crag HestWall Inn at Grange near Cartmel. Warton Crag . . . Breakwater Pole Grange Inn. Warton Crag ... Farleton Knot.. Flagstaff on Bolton- le-Sands Church Tower. 69,361 Warton Crag 71,743 HestWall.... \ Bolton Church. 82 4 80 41 Feet. 69,331 69,586 102 7 47 29 97 7 24 52 15 52 155 47 29 8 47 38 9 21 0 26 14 24 32,372 42,941 32,350 40,590 16,883 45,283 16,883 [ 262 ] XLIII. An Abstract of the essential Principles of M. Cauchy's View of the Undulatory Theory^ leading to an Explanation of the Dispersion of Light ,- with Remarks. By the Rev. Baden Powell, M,A,^ F,R.S., Savilian Professor of Geo^ met7y, Oxford, [Continued from p. 193, and concluded.] Tl| AVING thus obtained the expression which establishes -■--■• a general relation between the length of a wave and the velocity of its propagation, or the time of its transmission, or, again, (which is the same thing,) the time of the vibration of a molecule, we might proceed at once to certain more particular inferences ; but it may be useful, perhaps, here to premise a remark or two on the general nature of the inquiry respecting the theory of dispersion. The unequal refrangibility of the primary and component parts of which ordinary light is constituted, is a general fact, of which, as yet, no plausible explanation has been proposed, and which has presented great difficulties to any theory. These difficulties have, indeed, been triumphantly held forth by the opponents of the undulatory theory as absolutely fatal to its claims ; but the truth is they are by no means ^peculiar to this theory. The hypothesis of emission has not been at all more successful in affording any satisfactory explanation. Let us, however, look at the nature of the difficulty as it occurs upon the ordinary hypothesis of undulations. The front of a wave incident obliquely on the surface of a transpa- rent medium, and arriving successively, e, g. at any two points of the surface, at each originates a new spherical wave within the medium. If the refractive power be greater, these are propagated with diminished velocity. The second of these new waves within the medium has propagated itself a little way before the first has gone through the same space as the original wave in the same time. Hence the plane touching their contemporaneous surfaces will be inclined to the surface of the medium at a less angle than the front of the original wave; and (it is easily seen) precisely so much so, as that the ratio of the sines is that of the velocities, or is equal to the index of refraction. The refraction, then, depends solely on the diminished velo- city of propagation of the waves, and ought to be exactly the same for waves of all lengths, unless there could be shown any connexion between the length of a wave and the velocity of its propagation. " It is particularly to be remarked," observes Prof. Airy, M. Cauchy's Vim of the JJndulatory Theory of Light, 26S " that the difference of velocity does not depend on the mag- nitude of vibration of each particle, for it is the same whether the light be feeble or intense, that is, whether the vibration be small or great. Nor does it depend on the relative vibration of two contiguous particles, as that varies in the same propor- tion as the last, with a variation of the intensity. The only element which in conjunction with either of these will define the undulation, is the time of vibration : and it is, in fact, the time of vibration which distinguishes the different kinds of light. It would seem natural, therefore, to seek for an expla- nation of the difference of velocities in something which de- pends not on space but on time." These observations occur in the appendix to the author's profound paper on the double refraction of quartz in the Cambridge Transactions 1831; and thus far are perfectly general, and explain in the clearest manner the precise point to which our investigation ought to be directed in any attempt to remove the difficulty of the unequal refrangibility. These remarks, indeed, are introductory to a particular suggestion for explaining the difficulty, thrown out by the distinguished author. But it is not here intended to discuss this and other conjectural causes which have been proposed, and which may very possibly conspire to account for the re- sult The essential point aimed at in any legitimate inquiry of this nature is to show some relation between the length of an undulation and the velocity of its propagation; or in other words, that in transparent media the velocity of propaga- tion of the waves is different for the different primary rays, that is, for rays in which the lengths of the undulations are different. But, as we have seen, in the ordinary view of the theory of waves the equal refrangibility of all rays is a necessary con- sequence. The course, then, to be pursued by any judicious inquirer, and that, in fact, adopted by M. Cauchy, is that of reviewing the first elements of the theory, viz., the particular constitution of the hypothetical aethereal medium, and endea- vouring so to modify them, that while they shall apply equally to the conclusions deduced on the ordinary principles, and referring to the other phaenomena of light, they shall also be made to include results which will explain the phaenomena in question. Now, the great desideratum, the establishment of a relation between the length of a wave and the time or ve- locity of its propagation, is supplied, as M. Cauchy has ex- pressly remarked, " in general^'* in the formula before given. But, as was remarked at the beginning of these papers. 264 Prof. Powell's Abstract of M. Cuiichy's some more particular considerations have been lately sug- gested as to certain conditions which are necessary to be ob- served in order to the full application of M. Cauchy*s prin- ciple. In fact, it becomes necessary to inquire into the more particular nature of the relation he has established. To pro- ceed, then, to this inquiry, we will resume the simple expres- sion which gives the relation between the length of a wave and the velocity of its propagation, viz. The particular nature of the relation depends on the value of s; and for the inquiries to which we refer, it will be im- c portant to have before us the value of 5, or of ^, expressed in such a form as can be subjected to examination, so that we may determine whether it fulfills the conditions presently to be described. For this purpose, then, we must briefly deduce such a value of -p. k The value of s^ depends upon the quantities L, M, &c., which enter into the equation (29.); and the expressions which these letters were assumed to represent are all of a similar nature, consisting of the sums of products of several factors. Taking a single term of the sum, these factors may be thus simplified : From the assumption (22.) derived from the original equa- tions (12.), we have r (2m fir) . 9 /^rcosSx) ^ ~ I + { 2j«/Jr) cos' a sin' {^') } which is easily reducible to L = 2 « L(r) + cos^ af(r) _ ^j„, kr^, r 2 and on dividing by k\ we may put the expression into the form f . kr cos Z^\ L _ f (r) + cos^ «/(r) r^ cos^ S I sm -^ ~^ " ^ r * 2 • I ~~l:Tcos Z Again, on looking at the values of the other coefficients View of the JJndulatory Theory of Light. 265 M, N, &c., it will readily appear that they differ only in the particular form of the products of the cosines of a, /3, y, and are all reducible to forms similar to that just given for L ; that is to say, on dividing by F, reducible to a coefficient which shall be a function of tw, r, and the cosines ; and a se- cond factor, which is identical with that involving ^, r, and cos 8 : in other words, resolvable into two factors, one of which involves /:, and the other does not, but only quantities de- pendent on the nature of the medium, and not variable with a variation in k. Thus, designating for brevity the last term by c^ (^, r, cos 5) and the former we shall have 'by F(7» ,r,ct. &c.), L = F (;«, r,a) <^{k, r, cos 8) Now, if we tions (27.)? as &c, take either r, /3) . ^ (Ar, of the values r, cos of 5^ C A' from the equa- 5^ = L + '<5 + Q and substitute the above values of L, R, Q, we shall obtain the sums of similar terms with one common factor involving A-, which may again be collected under one general form of a function of m, r, a, /3, y. And as this is constant with respect to ^, we may express it simply by a constant coefficient : and since r cos 8, is also constant for the same medium, we may include this in the constant factor, and thus reduce cur ex- pression into the simplified form . kr cos S sm 5* = H« Or, again, since we have 2 k r cos 5 and for brevity writing cos 8 = w, we shall have sin (— ) = H \ r ) Third Series, Vol. 6. No. 34. April 1835. 2M 266 M. Cauchy's Vie^jo of the Undulatory Theory of Light. Now, to show that the velocity varies for waves of different o lengths is the same thing as to show that the ratio -v- is dif- ferent for different values of k, that is, of /; and this we can determine from the expression in the form in which we now have it. If, for instance, from the nature of the quantities, the last factor should not vary with a change in /, then the requisite condition will not be fulfilled. Now, the variable factor expresses the ratio of a sine to its arc, and this will be very nearly constant for a variation in / if the arc be ex- tremely small, that is, if —t- be very small ; or, in other words, tf the ratio of (r) the distance between two molecules to (/) the length of a wave be very small. It follows, then, with regard to the hypothetical nature of the aethereal medium, that if the interval between two mole- cules be very much less than the length of a wave, then the velocity will not sensibly vary with the length of a wave. In adopting the theory, then, with a view to its application to the facts, we must carefully observe the limitation thus imposed upon the primary nature of our hypothesis. It is a limitation which is perfectly admissible as regards any of the preceding deductions; and we must introduce it as an express condition, that a relation between the velocity and the length of a wave is established on M. Cauchy^s principles, provided the molecules are so disposed that the intervals between them al- ways bear a sensible ratio to the length of an undulation. The necessity of the fulfilment of this condition was the suggestion alluded to at first, and on the nature and import- ance of it, I made a few remarks in the Physical Section of the British Association at the Edinburgh meeting. But the ex- pression when reduced to this form presents for examination other points of still higher interest. The existence in general of a relation between the length of a wave and the velocity of its propagation (as already ob- served,) assigns a reason why rays whose waves are of dif- ferent lengths should be unequally refracted. But it becomes important, with a view to the more exact comparison of theory and observation, to be able to assign a more specific relation. Indeed the theory will be incomplete unless it enable us to show not only that some relation subsists between the length and the velocity of a wave, which shall vary both for each different ray and each different medium, but also that it is such as shall explain why the several rays are unequally AnalyticalDetermination of the Laws of transmitted Motion. 267 refracted, in the precise degree which prismatic observations indicate. This inquiry, of some difficulty but of the highest interest, whichever way it may turn out, I have been engaged in pro- secuting, and hope soon to be able to bring the results before the public. Meanwhile I would observe, with reference to the formula, that in deducing it from M. Cauchy's theory, I by no means intend to affirm that it cannot be deduced on any other prin- ciples. I have, in fact, heard it stated that an equivalent ex- pression may be obtained on less complicated considerations. It must, however, be allowed that no such deduction has been specifically made : and any mathematician who would make it, would be conferring a vast benefit on this branch of sci- ence, if, indeed, it should be found to stand the test of com- parison with exact observations ; if it should not, it will be- come the only course to attempt some further modification of first principles until we can deduce an expression which will represent the law of nature. XLIV. On the Analytical Determination of the Laws of trans- mitted Motion. By the B.ev, James Challis, M.A.* TN the Report on the Analytical Theory of Hydrostatics and ^ Hydrodynamics which is printed in the second volume of the Transactions of the British Association, I have ventured, under a persuasion that the cause of scientific truth might be benefited, to express some doubt of the accuracy in principle of the received method of determining the nature of trans- mitted motion. The question will be allowed to be an im- portant one by all who have turned their attention to this part of the application of analysis; but as it is somewhat of au abs- truse nature, I fear that what is there said may not be per- fectly understood without further illustration. For this reason 1 propose in the present communication to adduce a simple instance, which may serve to exhibit both the received method, and that which, as I conceive, ought to be substituted in the place of it. The instance here selected is that of the transmission of motion along an elastic chord fixed at both ends : this will answer the purpose intended as well as an instance of trans- mission of motion in fluids. Let the chord in a state of rest be in a horizontal straight line ; and at any position between the two extremities, let a limited portion, equal in length to * Communicated bv the Author. 2M 2 268 The Rev. J. Challis on the analytical Determination 2 /, be deranged from its quiescent state and put into any ar- bitrary shape, subject, however, to the condition that each point is very little removed from the place it would have had at rest, and no two consecutive elements of the chord make a large angle with each other. The deranged portion being held a while in its new position, it is required to find what will ensue when it is left to itself. Let y be the distance of any point of it from the horizontal line in which the chord rests, and X the distance of the same point, measured horizontally, from the middle of the derangement, t the time measured from a given instant. The known partial differential equation applicable to this case is where a^ = */ "-Zgc, g being the measure of the force of gravity, and c the length of the chord whose weight measures the tension. The integral of this equation is y = F(a;-al) -\-f(a:-\-at), (1.) from which is derived i -^ = — aY' {x—at)+af' (-^x + at), (2.) a V an expression for the velocity in a direction perpendicular to the horizontal line of abscissae. We may consider it as proved by Lagrange, that in assigning any particular forms to the d y functions which express the initial magnitudes of 3/ and — — , we are at liberty to take only such values of them as corre- spond to values of x lying between arbitrary limits, and may suppose the forms of the functions to be quite different for different intervals along the line of abscissae. Hence the equations (1.) and (2.) will apply to the case of derangement supposed above, and we may say, for instance, that the de- ranged portion of the chord shall take the form given by the equation y = h l\ ^j from x=— ltox~-\-h with- out considering any of the values of ^ that result from other values of x. The kind of motion that takes place when the chord is abandoned to itself would be inferred as follows, ac- cording to the received method, an instance of which may be seen in the Treatise on Sound in the Encyclopcodia Metropo- litaiia, Arts. 57 — 65. Let t be dated from the instant the motion commences, and of the Laws of transmitted Motion. 269 let ^ (:r) be the function that represents the initial values of y. Then at the beginning of the motion, <^(^)= F(^)+/(x) 0 = - a F (^) + af {x). Hence F (^) =.f'(x)\ and as <^' (jt) = F (.r) +/'(^), it follows that 4)' (x) = 2 F (x), and <^ {x) = 2 F (.r). So also <^ {x) — 2f(x), Hence Y {x—at) — ^, and when metallic contact was made there, very considerable deflection of the galvanometer needle at g. Platina also appeared to be dis- solved at the anode of the fused chloride at a, and there was every appearance of a decomposition having been effected there. 980. A further proof of decomposition was obtained in the following manner. The platina wires in the fused chloride at a were brought very near together (metallic contact having been established at /;), and left so; the deflection at the gal- vanometer indicated the passage of a current, feeble in its force, but constant. After a minute or two, however, the needle would suddenly be violently affected, and indicate a current as strong as if metallic contact had taken place at a. This I actually found to be the case, for the silver reduced by the action of the current crystallized in long delicate spiculae, Electrolytic Intensity required for Water, S^c, 277 and these at last completed the metallic communication ; and at the same time that they transmitted a more powerful cur*- rent than the fused chloride, they proved that electro-chemical decomposition of that chloride had been going on. Hence it appears, that the current excited by dilute sulphuric acid be- tween zinc and platina, has an intensity above that required to electrolyze the fused chloride of silver when placed between platina electrodes, although it has not intensity enough to de- compose chloride of lead under the same circumstances. 981. A drop oi "water placed at a instead of the fused chlo- rides, showed as in the former case (970.), that it could con- duct a current unable to decompose it, for decomposition of the solution of iodide at b occurred after some time. But its conducting power was much below that of the fused chloride of lead (978.). 982. Fused nitre at a conducted much better than water : I was unable to decide with certainty whether it was electro- lyzed, but I incline to think not, for there was no discolora- tion against the platina at the cathode. If sulpho-nitric acid had been used in the exciting vessel, both the nitre and the chloride of lead would have suffered decomposition like the water (906.). 983. The results thus supplied of conduction without de- composition, and the necessity of a certain electrolytic inten- sity for the separation of the ions of different electrolytes, are immediately connected with the experiments and results given in § 10. of the Fourth Series of these Researches (418. 423. 444. 449.). But it will require a more exact knowledge of the nature of intensity, both as regards the first origin of the electric current, and also the manner in which it may be re- duced or lowered by the intervention of larger or smaller portions of bad conductors, whether decomposable or not, before their relation can be minutely and fully understood. 984. In the case of water, the experiments I have as yet made, appear to show, that when the electric current is re- duced in intensity below the point required for decomposition, then the degree of conduction is the same whether sulphuric acid, or any other of the many bodies which can affect its transferring power as an electrolyte, are present or not. Or, in other words, that the necessary electrolytic intensity for water is the same whether it be pure, or rendered a better conductor by the addition of these substances ; and that for currents of less intensity than this, the water, whether pure or acidulated, has equal conducting power. An apparatus, fig. 12, was arranged with dilute sulphuric acid in the vessel ^, 278 Dr. Faraday's Experimental Researches in Electricity, and pure distilled water in the vessel B. By the decomposi- tion at e, it appeared as if water was a better conductor than dilute sulphuric acid for a current of such low intensity as to cause no decomposition. I am inclined, however, to attribute this apparent superiority of water to variations in that peculiar condition of the platina electrodes which is referred to further on in this Series (1040.), and which is assumed, as far as I can judge, to a greater degree in dilute sulphuric acid than in pure water. The power, therefore, of acids, alkalies, salts, and other bodies in solution, to increase conducting power, appears to hold good only in those cases where the electrolyte subject to the current suffers decomposition, and loses all in- fluence when the current transmitted has too low an intensity to effect chemical change. It is probable that the ordinary conducting power of an electrolyte in the solid state (419.) is the same as that which it possesses in the fluid state for cur- rents under the due electrolytic intensity. 985. Currents of electricity, produced by less than eight or ten series of voltaic elements, can be reduced to that inten- sity at which water can conduct them without suffering de- composition, by causing them to pass through three or four vessels in which water shall be successively interposed between platina surfaces. The principles of interference upon which this effect depends, will be described hereafter (1009. 1018.), but the effect may be useful in obtaining currents of standard intensity, and is probably applicable to batteries of any num- ber of pairs of plates. 986. As there appears every reason to expect that all elec- trolytes will be found subject to the law which requires an electric current of a certain intensity for their decomposition, but that they will differ from each other in the degree of in- tensity required, it will be desirable hereafter to arrange them in a table, in the order of their electrolytic intensities. In- vestigations on this point must, however, be very much ex- tended, and include many more bodies than have been here merjtioned before such a table can be constructed. It will be especially needful in such experiments, to describe the nature of the electrodes used, or, if possible, to select such as, like platina or plumbago in certain cases, shall have no power of assisting the separation of the ions to be evolved (913.). 987. Of the two modes in which bodies can transmit the electric forces, namely, that which is so characteristically ex- hibited by the metals, and that in which it is accompanied by decomposition, the first appears common to all bodies, al- though it occurs with almost infinite degrees of difference; Remarkable Conclusion in relation to Intensity, 279 the second is at present distinctive of the electrolytes. It is, however, just possible that it may hereafter be extended to the metals; for their power of conducting without decomposi- tion may, perhaps justly, be ascribed to their requiring a very high electrolytic intensity for their decomposition. 987J. The establishment of a certain electrolytic intensity being necessary before decomposition can be effected, is of great importance in all those considerations which arise re- garding the probable effects of weak currents, such for in- stance as those produced by natural thermo-electricity, or na- tural voltaic arrangements. For to produce an effect of de- composition or of combination, a current must not only exist, but have a certain intensity before it can overcome the qui- escent affinities opposed to it, otherwise it will be conducted, producing no permanent effects. On the other hand, the principles are also now evident by which an opposing action can be so weakened by the juxtaposition of bodies not having quite affinity enough to cause direct action between them (913.), that a very weak current shall be able to raise the sum of actions sufficiently high, and cause chemical changes to occur. 988. In concluding this division on the intensity necessary for electrolyzation^ I cannot resist pointing out the following remarkable conclusion in relation to intensity generally. It would appear that when a voltaic current is produced, having a certain intensity, dependent upon the strength of the che- mical affinities by which that current is excited (916.), it can decompose a particular electrolyte without relation to the quantity of electricity passed, the intensity deciding whether the electrolyte shall give way or not. If that conclusion be confirmed, then we may arrange circumstances so that the same quantity of electricity may pass in the same time, in at the same surface, into the same decomposing body in the same state, and yet differ in intensity, decomposing in one case and in the other not. For taking a source of too low an intensity to de- compose, and ascertaining the quantity passed in a given time, it is easy to take another source having a sufficient intensity, and reducing the quantity of electricity from it by the inter- vention of bad conductors to the same proportion as the former current, and then all the conditions will be fulfilled to pro- duce the result described. [To be continued.] [ '280 ] XLVI. Insectorttm novonim exoticortim [ex Ordine Diplero- I x\xm) Descriptiones. Auctore J. O.WESTWOODiF.L.S.Sfc* Gynoplistia, Westw. {Anoplistes\y Westw. in Zool. Journ. No. 20. ined.) /^TENOPHORJE affinis. Antennae in utroque sexu pectinatae, $ 18- ^ ? 17-articulatae. Alarum nervi ut in Ctenoph.Jlaveolatd dis^positi. Sect. 1. Antennae $ articulis 3— 17 unipectinatis. Sp. 1. Gyn. vilis. Ctenoph. vilis, Walk. Ent. Mag. 2. 469. Anoplistes nervosay Westw. Zool. Journ. No. 20. ined. Habitat in Nova Hollandia. — In mus. nostr. Sp. 2. Gyn. ct/anea, Westw. Nigra; abdomine chalybeo purpureoque ni- tenti ; femoribus tibiisque ad basin minus obscuris; alis obscure nervosis, costsi maculisque duabus subcostalibus fuscis : ? antennis mutilatis. — Long. Corp. lin. 6. Habitat in Nova Hollandia. — In mus. nostr. Obs. A Tipulidis omnibus colore metallico discrepat. Sect. 2. Antennae $ articulis 3-— 14 unipectinatis. Sp. 3. Gyn, hella. Ctenoph. helltty Walk. Ent. Mag. 2. 470. Anoplistes variegata, Westw. Zool. Journ. No. 20. ined. Habitat in Nova Hollandia. — In mus. nostr. Sp. 4. Gyn. annulata. West. ? Nigra ; thorace coxisque laet^ fulvis ; alis fuscis ; abdomine sericie subaurea obtecto ; tibiis annulo centrali albo tarsisque basi fulvescentibus ; antennis $ 17-articulatis, articulis 3 — 9 ramum brevem obtusum emittentibus, lOmo intern^ acute producto, re- liquis simplicibus. — Long. corp. lin. 5. Exp. alar. lin. 9^. Habitat in America Septentrionali. — In mus. D. Hope. Ptilogyna, Westw. Tipula afhnh. Antennae in utroque sexu pectinatae; $ 1 S-articulatae, ramulis 7 internis, 15 externis longis ; $ H-articulatae, ramulis 7 internis, 8 externis brevibus. Alae cellula discoidali subapicali 7-angulata, fere ut in Limnobid tiisulcata Schumm. Sp. 1. Ptilog. ramicornis. Tipula ramicornii. Walk. Ent. Mag. 2. 469. Ptilogyna marginalis, Westw. Zool. Journ. No. 20. ined. Habitat in Nova Hollandia. — In mus. nostr. OzoDiCERA, Macq. Dipt. p. 92. (He77iicteina, Westw. in Zool. Journ. No. 20. ined.) Sp. 1. Ozod. pectinaia, Wied. iOzod. ochracea, Macq. loc. cit.) * Communicated by the Author. •j- I have been compelled to alter this name and that of Ozocera, pro- posed by me for two Tipulideous genera in a memoir forwarded several •^^ ->,j years since for publication in the Zoological Journal, (and which has been ^^^A^t. *^' printed off nearly twelve months,) M. Serviile having in the mean time em- ployed Anoplistes for a genus of longicorn beetles, and M. Macquart that of Ozodicera for a genus ofTipulidtB for which in the same memoir I had pro- posed the name of Hemicteina. The specific names of several of the in- sects described in the same memoir will also sink into synonyms, Mr. Walker having published a description of them in the Entomological Maga- zine for January 1835. In like manner my Aschiphasma annulipes will sink into a synonym of Ferlamorphus hieroglyphicns of Mr. G. R. Gray*s monograph upon the Phasmidce, just published. The great convenience arising from the publication of scientific works at short intervals, such as the Philosophical Magazine, is thus especially evidenced. Mr. D. Griffin 07i an unusual Affection of the Eye. 281 ^ Sp. 2. Ozod. gracilis, Westw. Fusco-ochracea ; rostro subfiilvo; anten- nis fuscis, basi ochraceis ; thorace subvittato ; alis subfumosis, nervis stig- mateque ochraceis. — Long. corp. lin. 10. ^ . Habitat in Brasilia. — In mus. nostr. Ceuozodia, Westw. (Ozocera,Westvr, Zool. Journ. No. 20. ined. — nee Ozo- dicera, Macq.) LivmobicE affinis. Antennae thorace paulo longiores, articulis 32 ; 3 — 31, ramulum longum emittenti. Palpi perbreves. Alarum nervi ut in Gynoplistia vili dispositi. Sp. 1. Cer. inter rupta, Westw. Ochracea; ramulis antennarum subfuscis; alis maculis 4 parvis discoidalibiis longitudinaliter collocatis, cinereis. — Long. Corp. lin. 10. In mus. D. Hope. Habitat in Australia apud " Swan River." BiTTACOMORPHA, Westw. Genus anomalum Tipulariis terricolis, Latr., evidenter pertinens. Caput et thorax parva. Abdomen valde elongatum et depressum. Pedes longitu- dine mediocres; femoribus tibiisque gracilibus; tarsis basi dilatatis dense ciliatis. Alae nervis perpaueis, fere ut in genere Sciophila dispositis. Antennae graciles, filiformes. Palpi capitis longitudine, articulis 4 aequalibus. Lobi labiales niagni. Ocelli 0 ? Sp. 1. Tipiila clavipes. Fab, Sp. Ins. 2. 404. Ftychoptera clavipes, Fab. Syst. Rhyng. Wied. Auss. Zweifl. Ins. 1. 59. — Long. corp. lin. 8. Exp. alar. lin. 8^. Habitat in America Boreali. In Insult Newfoundland. — In mus. nostr. — Commun. Dom. Churton. Midas maculiventris, Westw. Obscure niger; abdomine testaceo-fuscanti, segmentis apice pallidis et (nisi segmentis duobus basalibus) macula triangu- lari obscura in medio notatis; hae maculae versus apicem abdominis magni- tudine crescunt : segmento anali fusco ; abdomine toto subtus concolori; alis flavido-tuscantibus, regione nervorum internorum colore obscuriori tincta. — Long. corp. lin. 11. Exp. alar. lin. 19. Hab. ? — In mus. nostr. MiUAS auripennis, Westw. Niger; capite.cum antennis, pedibus (nisi basi femorum) abdomine (nisi segmento basali marginibusque terminalibus seg- mentoruni 2 et 3,) laete luteis ,• alis auricoloribus, macula versus apicem costae nigra, margineque interno pallido, mesosterni lateribus unispinosis. Alarum nervorum directio Midasibus veris paulo discrepat. — Long. corp. lin. 11. Exp. alar. lin. 19. Habitat in Nova Hollandia. In mus. Hope et nostr. Midas viduatus, Westw. Niger; faciei thoracisque lateribus, et macula triangulari utrinque ad basin segmentorum 3 et 4 abdominalium, sericie argentea obtectis ; alis pallidis in medio fuscantibus, nervis fuscis.— Long, corp. lin. 10. Exp. alar. lin. 16. Habitat in Nova Hollandia. — In mus. nostr. XL VII. On an unusual Affection of the Eye, in nsohich three Images were produced. By D. G ii i ffi N, Esq. * n^^HE following affection of the eye is, I believe, a very iin- ■'■ usual one. I have seen no account of such a phacno- menon in any of the writings on the physiology of vision, and * Communicated by the Author. Third Scries, Vol. 6. No. 34. April 1835. 2 O 282 Mr. D. Griffin 07i an imusual Affection of the Eye, shall feel gratified if I can learn whether it has ever been ob- served by others. One day in the early part of last July, after having spent a considerable time in looking at various land objects through a telescope, 1 perceived a very great indistinctness of vision after I had left offj which I soon found existed entirely in the left eye. I had kept this eye closed while I was at the tele- scope ; and having often observed before that some indistinct- ness of vision occurred in the same circumstances, I attri- buted it to the weakness of sight that would naturally follow from havhig kept that eye unemployed while using the other, and did not mind it much at first. It seemed now, however, so great that I covered the right eye to examine the state of the other more particularly. I then found, with some surprise, that it gave more than one image, and on directing it towards a box on the chimney- piece, about eight or nine feet from me, on the front of which were some large and extremely well printed letters, I per- ceived that there were three distinct images of those letters placed vertically one above the other. The lowest, which I shall call the true image, was undisturbed from its proper place. The dislocation of the second im.age was just so great as to make it overlap more than the upper half of the last- mentioned, and its light was scarcely, if at all, inferior to that of the true one. The light of the third was much more faint than that of either of the others, and its displacement was such as to allow it still slightly to overlap the true image at its upper edge, where the combination of the three images pro- duced a dark line along the letters exactly similar in appear- ance to overlying shadows. There was not the least displace- ment towards either side, unless I changed my head from an erect position ; and 1 could not find any trace of a fourth image by the closest examination. This affection lessened gradually in the course of the evening, the false images slowly descending to their true place, and next day that eye was as perfect as the other. I was for some time puzzled to account for this strange ap- pearance. It seemed difficult to suppose that any functional derangement of the retina could give origin to three images so distinct and separate ; and though a double image is some- times an attendant upon amaurotic affections of the eye, yet this, so temporary in its nature, could hardly be classed with such complaints. The cleanness and good definition of the images seemed to indicate some optical change ; and besides this, the distortion occurring all in one plane evidently pointed to some single cause, and that probably a mechanical one, as the origin of the whole pha^nomenon. Mr. D. Griffin on an unusual Affection of the Eye. 283 The effect, however, produced was such as would result from a distortion or bending back of the upper part of the crystalline lens, producint^ an effect not exactly like spherical aberration, but like what would arise from the axis of that part of the lens losing its parallelism to the axis of the centre and other parts, which would tend to throw the image pro- duced by that part in the direction in which the distortion of the axis lay. In order that a correct idea may be formed of the degree of the displacement, it is necessary to mention that the letters which I looked at, at the distance of three yards, and of which the different images were separated to the degree mentioned above, were about |ths of an inch in height and about the same in breadth. The only thing that occurred to me that could produce such a distortion was the pressure of the upper eyelid on the eyeball, which was very considerable and long continued. That the distoj'tion was in the lens alone seems probable, be- cause, from its half-solid state, it is almost the only part of the eye that would retain the effect of pressure for any time ; but if the altered shape of the lens was the cause, the altera- tion must have been an exceedingly peculiar one. To pro- duce the three images above mentioned it must have had two sudden bendings backwards; one somewhere near the middle, and the other near the upper edge. The lower half, which 1 suppose to have been undisturbed, would in that case have given the true image ; the part immediately above, which was bent backwards in some degree, would have formed an image lower on the retina, and therefore higher to the perception than the true one; and the highest part, or upper edge, of the lens, which was most distorted, would have given the lowest image on the retina, and therefore the highest to the perception. But here came the difficulty : on considering the structure of the lens as far as that is at present known, and how its density lessens gradually from the centre to the circumference, it seemed extremely hard to suppose that any bending could take place in it otherwise than very gradually, and in a re- gular curve. This gradual bending, it is evident, would not be indicated by the perception of multiplied images, but by great indistinctness and haziness in the upper part of the ob- ject; yet of either haziness or deficiency of outline in the images there was not the least appearance. I have tried repeatedly since to produce the same appear- ance by simply covering the left eye while using the right, and otherwise observinjx the same circumstances, but 1 found that 2 02 234' Prof. Forbes on the Uefraction and Polarization of Heat. the pressure of the eyelid was always essential to the success of the experiment. I have only further to add, that I should be glad to have the opinions of those who are interested in the physiology of vision on this curious fact, as I find it exceedingly hard to conceive how such a change in the lens as I have supposed, could be produced by any pressure, however exercised, of the eyelid. Pallas Kenry. Feb. 1, 1835. D. Griffin. XLVIII. On the Refraction and Polarization of Heat. By James D. Forbes, Esq., F.R.SS. L. Sr E., Professor of Na- tural Philosophy in the University of Edinburgh. [Continued from p. 214.] §. 4?. On the Depolarization and Double Refraction of Heat by Crystals. 46. T^HE analogies which have hitherto guided us from the -*• laws of light to those of heat, suggest that it is far from improbable that the influence of crystallized bodies upon pola- rized light, which produces the most splendid and most varied, but, at the same time, amongst the most determinate phaenomena of optics, may have a counterpart in the science of heat. The simpler of these, of course, it is our. object first to verify; and, to a certain extent, this is all that is necessary, in order to complete the analogy of heat and light in this particular case; for the conditions essential to their production in the case of light, are on all hands admitted to depend on the susceptibi- lity of the principle of light to undergo certain modifications in certain circumstances, extremely limited in number, and which then produce, as necessary consequences, all the sub- sequent effects. If we find that heat undergoes the same changes under the same circumstances, so far as we can detect them, there is the highest probability in favour of the extended analogy ; for if there be a necessary sequence in the one case, it must be inferred also in the other. 4-7. When polarized light is caused to pass 'through a cry- stallized body possessing the power of double refraction, it hap- pens, in a great majority of the conditions under which the experiment may be made, that the light, on emerging from the crystal, has undergone some change. This change may, for instance, render it capable of reflection at a surface inclined to the rays of light at the polarizing angle, which they were incapable of doing before the crystal was interposed, or if be- Prof. Forb6s on the Refraction and Polarization of Heat. 285 fore capable of reflection, they may now be partially, or wholly, incapable of it. Such a mode of action may in general terms be called depolarization^ an expressive term, though not quite correct; or as has more lately been proposed, in conformity with the more accurate views now entertained on the subject, Di'polarization, indicating that the action of the interposed crystal is to separate the incident polarized ray into two parts by its doubly refracting energy ; which parts are polarized in rectangular planes, and by their union produce the modified effect. But whatever be the explanation which we adopt of the curious and complicated changes which doubly refracting crystals exercise in the case of light, it is clear that the esta- blishment of a correlative fact in regard to heat unaccompanied by light, must force us to admit an identity of the laws which combine, by a singularly refined mechanism, to produce an identical result. The theory of undulations is in fact by far the simplest that v/e can adopt, and it requires us, if we admit depolarization, to admit the existence of double refraction and of interference. 1'lie demonstration, then, of such a property of heat, is one of such importance, as to require the fullest proof. 48. The power of mica to depolarize heat, I discovered on the 16th of December last. If in the case of polarizing light, whether by reflection or refraction, the planes of incidence re- latively to the polarizing and analysing plates be at right angles to one another, the light is wholly (or at least in great part) stopped. The plates remaining in this position, it is well known, that if a film of mica be interposed between them, so as to be perpendicular to the incident light, that light will no longer be stopped excepting in two positions, namely, when the Principal Section of the mica plate (or the plane contain- ing the two axes) is parallel or perpendicular to the plane of polarization. In intermediate positions, light reaches the eye. This is true for all thicknesses of the film of mica onl}' where light of different degrees of refrangibility is combined: with perfectly homogeneous light, at certain thicknesses, no light would in any position reach the eye, that is, it would not be depolarized. , 49. The analogous fact, in heat, would of course be indi- cated by interposing a film of mica between a polarizing and analysing plate, having their planes of incidence inclined at right angles to one another, and observing whether any differ- ence of heating effect appeared when the Principal Section of the plate was parallel to the plane of Primitive Polarization, or inclined 45° to it. 50. The very first experiments which I tried, seeined deci- 286 ProF. Forbes on the Refraction and Polarization of Heat. sive on this point. I employed the piles of mica for polarizing by transmission, and interposed successively two plates of mica so arranged that the Principal Section was in the one parallel (or perpendicular), and in the other inclined 45° to the plane of Primitive Polarization. Tliese were cut from the same piece, and precisely of the same thickness ; but I afterwards employed one and the same plate, inclined alternately in two positions. By the first experiments with dark heat (tempera- ture about 700") the polarizing mica plates (E and F) being crossed, the ratios of heat transmitted, when the principal sec- tion coincided with the plane of polarization (when the depo- larizing effect was nothing), and when it was incliiicd 4<5<» (when the depolarizing effect ought to be a maximum), were the following: 100:120 100:110 100:122 100:125 With different polarizmg and analysing plates, viz. C and D, the following ratios were obtained also for dark heat: 100:118 100:120 100:120 100:113 51. We have seen that the heat of Ifica7idescent Platinum is highly polarizable; it is also powerfully depolarized, as the following proportions obtained with polarizing mica plates, and the same interposed films as before, indicate, as the prin- cipal section was inclined O*' or 45 : 100:126 100: 138 100: 138 52. There were two distinct interposed plates employed for these experiments; their thickness was such as to transmit the red of the second order of the Newtonian Scale, when viewed by polarized light, analysed at right angles to the plane of po- larization. To show that no appreciable difference existed in their power of stopping common or unpolarized heat, and to point out the accuracy of such determinations, I may quote the following experiment on the transmission of unpolarized non-luminous heat through the two plates. Plate with sides inclined 0' and 90° Plate with sides inclined 45° to Principal Section. to Principal Section. , Q , o . Mean. ^^i \ 18«-25 18r 18i { '^ I 17-9 18x1 18 ) 18-25 18 + The reduction is performed as in art. 20. These quantities Prof. Forbes on the Refraction and Polarization of Heat. 287 were observed with the naked eye, and may therefore be con- sidered as coinciding in the two columns. 53. In repeating these experiments with a single film of mica, which was alternately placed with its axis parallel or inclined 45° to the plane of primitive polarization, similar re- sults were obtained. With incandescent platinum, the result is of the most striking character; under favourable circum- stances, the needle moves through from 2° to 3°. (a quan- tity, it will be recollected, of which a twentieth or a thir- tieth part is capable of measurement by the improved method of observation,) or even more, commencing the moment that the change in the position of the mica film is effected (which I generally perform with long forceps, so as to avoid the near approach of the hand to the pile). A few of the first expe- riments gave for the ratio of the effect on the pile in the two positions, with a single plate, 138:100 118:100 116:100 Another series, 1 30 : 1 00 1 25 : 1 00 123:1 00 A third, 120:100 120:100 A fourth*, 128 : 100 123 : 100 122 : 100 54. The depolarizing effect of this mica plate (which also gives by polarized light the red of Newton's second order,) upon non-luminous heat, was also exceedingly well marked, as I shall presently show, and amounted generally to between 0°*5 and 1°, as the statical effect; but as the source of heat requires to be closer to the mica plates, more is transmitted by conduction, which constantl}^ tends to diminish the ratio of the true difference of effect, as observed in (23). 55, It occurred to me, that since thin plates of mica pre- sent comparatively little resistance to the passage of heat, a very thin plate might perhaps depolarize more heat than it stopped, and thus we should have the paradoxical effect of an interposed obstacle increasing the effect, a mode of action which I thought I perceived in a thicker plate. I was at first surprised to find the reverse the case. 56, A film of mica which transmitted a slightly blue white of the first order (by polarized light), and which was capable of polarizing light circularly (nearly), was employed for this experiment. But not only was 1 unable to detect any increase of effect when it was placed between the polarizing and ana- lysing plates (E and F) crossed so as to give a minimum of transmitted heat, but there was an evident interception when it was interposed. In other words, it stopped more heat than it depolarized. This was true both with non-luminous heat » Observed by Dr. Traill. 288 Prof. Forbes ofi the Refraction and Polarization of Heat, and with that from incandescent phitinum. When I pro- ceeded to estimate its depolarizing power by the usual method of placing the Principal Section at 0° or at 45°, I totally failed in obtaining a sensible effect with non-luminous heat, and with incandescent platinum it was extremely faint. My sub- sequent experiments gave for the proportion of the depolari- zing effect to the whole heat which reached the pile when the plates E and F were crossed, Non-luminous Heat. Incandescent Platinum. Argand. •00 -OK) -03 But upon performing this experiment with a thicker plate, namely, that before alluded to in (53) and (54), I found that where it was interposed between the crossed polarizing and analysing plates, the quantity of heat which reached the pile was increased by that interposition by about 0°*5. Hence we have the singular spectacle of the transmission of heat being greater when a thick obstacle is interposed, whilst the direct effect is actually diminished by the interposition of a thin one. This effect was of the most marked character with heat from incandescent platinum; with dark heat the result was quite analogous, but within narrower limits. With unpolarized dark heat, 1 found that the thin plate stopped 30 out of 100 rays, whilst the thick one stopped 65^ or more than twice as much. 57. The depolarizing effect of mica was tried under every variety of circumstance, and with the most conspicuous and coincident results. The quantity of light accompanying the heat, appeared by no means to regulate the quantity of heat depolarized. The heat emitted from platinum, of a full red, (and therefore not vividly incandescent,) was one of the most fiivourable. Heat from an Argand lamp, with glass chimney, was also employed, and absolutely non-luminous heat from brass about 700°. I also employed mercury in an iron ves- sel, at about 500°, and found the results admirably marked. Pursuing the experiment as the temperature of the mercury descended, I found the effect still very sensible at 220°, and then lhou-;ht of trying hot water, which 1 had not done since I devised the telescopic method of observing the galvanome- ter (6). The result was, that, by most decisive experiments, I found that heat under 200° Fahrenheit^ is capable of being dejwlarized by mica. Even where I did not measure the amount, the instantaneous motion of the needle in the proper direction, when the Principal Section of the mica plate was parallel, or inclined 45"" to the plane of primitive polarization, gave as strong evidence to this fact as to any other I have recorded. Prof. Forbes on the Uefraction and Polarization of Heat, 289 58. It would be quite impracticable to give any detailed ac- count of my experiments on depolarization within moderate compass. It may be satisfactory, however, to mention, that, upon an examination of all the experiments I have recorded, I find that (excluding those on the thin plate of mica men- tioned in (56),) amongst 157 numerical comparisons, for the purpose of obtaining the depolarizing effect, only one gives a negative, and one a neutral result; and these exceptions occur in observations made upon heat of the lowest temperatures, namely, fiom mercury under 500°, and water under 200°. These experiments were made with heat from the various sources mentioned above (57), and with three different mica plates. The comparisons were always made from alternate observations, as in (20) and (52). Of these 157 comparisons, no less than 92 were made with heat wholly unaccompanied by visible light. 59. These conclusions, derived entirely by the use of mica as the depolarizing crystal, I endeavoured to confirm in the case of some others. Selenite, from the thin lamina? into which it may be split, naturally suggested itself, but 1 found that its interceptive power for heat is so much greater than that of mica, as to render these experiments nearly abortive. With heat from incandescent platinum, however, 1 got toler- ably marked indications of its action. 60. With tourmaline I was more successful. Not only was I able to obtain decisive depolarization when slightly luminous heat was employed, such as that from incandescent platinum, and the principal section of the tourmaline was alternately pa- rallel, and inclined 45° to the plane of primitive polarization, but also when dark heated brass was used (at 700°). The tourmaline was one of those marked C and D (21), not mounted on glass, and of a pale amber colour. 61. From these experiments, the depolarization, or Di-po^ larization of heat seems unquestionably established, whence admitting that it depends on the same mode of action as the corresponding facts in the case of light, which seems certain, we are bound to admit that heat (even that from warm water), is susceptible of double refraction, that the two pencils are po- larized in opposite planes, and that they become capable of in- terfering by the action of the analysing plate*. 62. These results we hold to be direct conclusions from the establishment of the existence of a mode of action, of a very * I made one attempt to obtain polarizing effects by means of Mr. Nicol's very elegant single-image calcspar pri;.ms, but without success, as I had an- ticipated, from the great proportion which the thickness of the spar neces- sarily bears to its aperture. Third Series. Vol. 6. No. U. April 1835, 2 P 290 Prof. Forbes on the Refraction and Polarization of Heat, complicated character, which nothing but an acquaintance with the corresponding facts with regard to Hght could have taught us how to look tor, and which, by coinciding with these, indicate a common mechanism. Hence, too, were our senses or our instruments capable of perceiving them, we should ne- cessarily discover, by the passage of heat along the axes of doubly refracting crystals, all the elegant forms of rings and brushes, defined by heating, instead of luminous rays. 63. But this analogy may be carried still further. So de- finite are the experimental results in depolarization, that I thought of comparing the intensities of the effects with those produced in light; and for this purpose, our method of esti- mating heat is far more satisfactory than those for estimating the intensity of illumination. The fundamental law, which I felt most anxious to verify, was the complementary nature of the transmitted heat, when \\\e jjlane of analysation is parallel, and when it is perpendicular, to the plane of polarization, 64-. It is well known in the case of light, that when no cry- stal is interposed between the polarizing and analysing plates, or when the crystal has its principal section parallel or per- pendicular to the plane of primitive polarization, the whole of the light is stopped* when the plates are perpendicular or crossed; the whole is transmitted when they are parallel. If the principal section of the crystal be now inclined 45° to the plane of polarization, the depolarizing effect is a maximum, a portion of light now being transn'iitted to the eye, the plates remaining crossed, which was not transmitted before, and, in like manner, a portion of the light which was formerly trans- mitted when the plates were parallel being now stopped. Now these two quantities are equal to one another, and therefore the sum of the intensities of illumination in the two cases (plates parallel and plates crossed) is a constant quantity. Now these two pencils correspond to the ordinary and extraordi- nary image in an analysing prism of calcareous spar. Let us call these intensities O^ and E^. Let the whole quantity of polarized light, or the value of O^, when the principal plane of the crystal coincides with that of polarization, be F^, and, under the same circumstances, E^= zero. Then since the two effects are complementary, whatever be the position of the principal plane, O^ + E^ = const. = F^ ,ind E2 = F — O^; or the whole intensity gained by the extraordinary pencil * That is, not reflected when the light is analysed by reflection, or not transmitted when it is analysed by refraction. In these experiments the latter method was always used. Prof. Forbes on the Refraction and Polarization of Heat, 29 1 (which at first was zero), by the depolarizhig influence of the crystal, is equal to that lost by the ordinary pencil. Q5, That the same law holds in the case of heat, the expe- rinients, of which the followin ney.) '^ L No. 1 No. 2 4 4 0-97 1-90 4 4 100 1-74 Mean r 8 ) comp. 1-43 ( ^ 1 comp. 1-37 [To be continued.] 2P2 [ 292 ] XLIX. Description of a new Spirit-lamp Furnace. By ARTrfUR Trevelyan, EsqJ* TTAVING lately been engaged in following out chemical -■--■■ analysis under the able direction of William Gregory, M.D., Edinburgh, I found that a lamp for generating a great heat would be highly useful, and was much wanted by the analytical chemist. After experimenting to a great extent with many modifications of the lamps of 13erzelius and others, I found that they all wanted power, and when used for a length of time, attained such a temperature that the spirit boiled and flowed over. After continuing these experiments for nearly three months, I had almost relinquished them in despair of success, when I accidentally became acquainted with Andrew Whelpdale, a young and promising chemist, to whom I stated my difficulty : he recommended, if it could be contrived, that the vapour of alcohol should be used. I immediately came into his view, and had a lamp constructed, of which a drawing is inclosed (see the figure). After trying it with different burners, a stop-cock and safety-valve (neither of which is necessary) and differently formed chimneys, it was brought to a state of perfection and power "which we little expected. It fused liquid as water, 500 grains of bicarbonate of soda in fifteen mi- nutes, consuming three ounces of alcohol, and I think might do it in less time, but the chimney was rather small for the size of the platina crucible used : the ends of the brass uprights attached to the rim on which the chimney stands were fused in a similar experiment. From its great power I think it may be called emphatically the " Lamp-furnace." It may be made of any size, but the chimney must be suited to the crucible, round which the flame should play freely. The vapour may be generated by a spirit-lamp placed under- neath the globe. * Communicated hv the Author. EeviewS) and Notices respecting New Booh. 293 My friend Dr. W. Gregory exhibited this lamp on the 11th of September to the Chemical Section of the British As- sociation at its late meeting in Edinburgh. Explanation of the Figure. A. Copper globe for holding the alcohol, with bottom slightly concave to concentrate the flame of lamp placed below. B. Opening covered with screw-cap, for introducing the al- cohol ; a conical safety-valve with worm spring may be attached if wished. C. Screw shank of Argand burner. D. Argand burner pierced with ten holes: this burner is the same as the gas burner used in Edinburgh, but with half the number of holes. E. Copper chimney within which the crucible is to be placed. F. Cupola, open at top. G. Ends of wires, similar to that marked H: there are three of these witii the ends inside, on which the crucible rests, bent at right angles. L. Reviews^ and Notices respectifig New Books, The West of England Journal of Science and Literature. Edited by George T. Clark. No. I. January 1835. To be continued Quarterly. Bristol. 8vo. Part I. Science, pp. 88. Part If. Li- terature, pp. 36. IN the Address explanatory of the intention and objects of this work, which is prefixed to the first Number now before us, it is stated '* that during the last few years the tastes and pursuits of a large section of the inhabitants of Bristol have been undergoing a gradual but important change. Science and literature have be- come more popular, the tone of general conversation has improved, and the demand for instructive and profitable books has propor- tionably increased." The improvement of the City Library and the establishment and prosperity of the Bristol Institution are cited as manifestations and evidences of this change ; and the consequence is drawn that a journal devoted to the encouragement and direction of pursuits which have become so generally appreciated will be sup- ported by the inhabitants of Bristol and the neighbouring places. The physical character and the archaeological interest of the extent df country of which that city is the metropolis, are brought forward in addition to the other causes out of which the prospects of the West of England Journal originate. This work is further designed to open a channel for the publication of the most valuable original communications which may from time to time be made to the Phi- losophical and Literary Society attached to the Bristol Institution, and eventually for that of communications made to other provincial societies. " With regard to science," it is observed, " we shall en- deavour to avail ourselves of all the peculiar local advantages afforded 29* Reviews, and Notices respecting New Books. by the very interesting geological situation of this metropolis. Placed in the centre of a rich coal-field, and yet on the edge of the great range of the oolites, and within a few miles of the cretaceous downs of Wiltshire, on the one side, and the transition chains of the Quantocks and Exmoor on the other; we have, taking Bristol as a centre, within a circle of thirty miles, every geological formation, from chalk to transition slate. Every walk through the lovely dales which diversify our scenery, is as rich in geological interest as in picturesque beauty ; and we may hope to open to our readers a new and copious source of instruction and pleasure in their daily excursions." The means for the cultivation of Zoological science afforded by the Museum of the Bristol Institution, and the advantages which its laboratory and apparatus afford for the repetition of experiments and the prosecution of original researches, in Chemistryand in Elec- tricity, are also enumerated among the circumstances connected with the establishment and expected support of this Journal; it being undoubted by the Editor, " that the city where, in his early life, Davy started as the assistant of Beddoes, will again yield an efficient supply of labourers in the advancement of science." The Address concludes with a statement of the objects of the work with respect to Literature, on which, however, it is not our province to enlarge. Entertaining the best wishes for the success of the West of En- gland Journal, and concurring altogether in the propriety of its establishment, on the grounds which we have noticed, we may now take a view of its contents. The first part of the Number, devoted to Science, commences with an " Essay Introductory to Geology, by the Rev. W. D. Conybeare." This contains, in suc- cession, a sketch of the order of geological formations, and of the organic remains which they present, with a concise tabular view of the inferior, secondary, and tertiary rocks, a notice of the disloca- tions and disruptions which appear to have affected the strata, and a statement of the more obvious inferences of theoretical geology. In his next communication, (to appear in the second or April Number,) Mr. Conybeare will proceed to the local facilities which the neighbourhood of Bristol presents to the study of geology. Mr, Conybeare's synoptical table of formations is a modification of part of that given by him in the " Outlines of the Geology of England and Wales:" he makes the following remarks on the asso- ciation of the carboniferous group with the transition class of rocks : " With these [the transition rocks] it is clear that the carboni- ferous series of rocks must, from the close generic relation of their organic remains, both animal and vegetable, be associated as the upper group of the same order. The anthracite, or culm alternat- ing with the roofing slates of North Devon, is in fact a true grau- wacke coal -formation, and closely agrees in the relics of vegetables which it exhibits, with the great coal formation*." (p. 4.) * See our Number for January, p. 67. Reviews, and Notices respecting New Booh, 295 In our review of Mr. Conybeare's article on the progress of geo- logy ill the Second Report of the British Association, we noticed his adoption and explanation of the views of Leibnitz, with respect to the original igneous fluidity of the nucleus of the globe, and the formation of its present crust in part from the refrigeration of the surface of this nucleus*; — proceeding with these views he now draws the subjoined inferences with respect to those entertained by the newly elected President of the Geological Society : *' This view of the subject is well illustrated, in some of the dia- grams in the concluding volume of Lyell's very able elements ; but he [the reader] will perhaps draw a further inference from these very re- presentations, which that author has failed to draw ; for he may see in them an evident reason why the perturbations of this igneous mass, acting in the earlier periods, when the crust which confined it was as yet in a thin and almost nascent state, and could therefore have opposed but a comparatively trifling resistance, must have produced effects incalculably superior in degree to those for which they are at present adequate, when repressed by the enormous column of resistance which the whole thickness of the actually consolidated crust at present offers. If we believe, as Mr. Lyeil is most anxious that we should believe, that the laws of nature are ever permanent and uniform, we must admit it as one of the plainest of those con- stant laws, " that the same given force, when it acts under a less re- sistance, must necessarily produce for more powerful effects than when it acts under an increased resistance" And if I may be allowed this axiom, 1 hold myself able to prove, from Mr. Lyell's own diagram, as clearly as any mathematical truth may be demonstrated from the diagrams of Euclid, the proposition which nevertheless he some- what unaccountably supposes himself to be opposed to, namely, that the actual convulsions of the crust of our planet neither are, nor, on the evidence which he has himself adduced, can possibly be, equal in intensity to those which prevailed in the earlier geological epochs. Instead, therefore, of comforting ourselves, as he does, with the prospect that we may expect in our own days convulsions violent as those which upheaved Mont Blanc, or *'Chimborazo, giant of the western shore," we may rather repose with Leibnitz, (assuredly not a less philosophical authority,) in the persuasion, " Tandem quiescentibus causis, atque aequilibratis, consistentior emergeret rerum status." (p. 18.) The next article in the Number is " An Introduction to Zoology, in illustration of the zoological department of the Museum of the Bristol Institution," by the Editor, Mr. Clark, with the assistance of some of that body <' of which he is the organ," but by whom *' the Journal has been placed under his immediate and unfettered superintendence." This article, likewise to be continued in suc- ceeding Numbers, consists of a physiological outline of the subjects and objects of zoology, in the course of which are enunciated some philosophical views not unworthy, we think, of the existing state of the science. At the same time we must admit that we cannot agree with the authors on the subject of the gradual succession of affini- * See Lond. and Edinb. Phil. Mag., vol. iv. p. 427—428. $96 Reviews, a?id Notices respecting Nexv Books. ties ; and we may also state our opinion that a more detailed ex- position of tlie subject of classification would render this series of papers still more valuable to the class of readers for whom it is de- signed. The third article is a paper by Mr. Samuel Stutchbury, the very efficient and meritorious Curator of the Bristol Institu- tion, read before the Philosophical and Literary Society in March 1832. It embodies, in a popular form, an outline of the history of coral reefs and islands, derived in part from various published authorities, but corroborated by the results of the author's personal observations made among the islands of the Dangerous Archipe- lago, and others of the Southern Pacific Ocean. A notice of Professor Faraday's recent discoveries with regard to the laws of electro-chemical decomposition, (some time since trans- ferred to our pages) a paper on the interference of the aerial waves propagated by the tuning-fork, by Mr. R. Addams, an article on Horticulture, and another on the Polders of Flanders, conclude the original communications, which are followed by Reviews, and sci- entific notices. These latter terminate the scientific division of the Number ; but we may notice, among the contents of the Second Part, allotted to Literature, as intimately connected with the sub- ject of the natural history of the human species, •* An Ethnogra- phical Memoir on the Nations of Slavonian Race," from the pen of Dr. Prichard. — Regarding the design of the West of England Journal to claim the warmest encouragement, and the specimen of the execution of that design now before us, to be at once deserving of considerable commend ation, and an earnest of future excel- lence, we hope that the success of this work will be such as to ful- fill the wishes of its founders and supporters. A List of tivo Thousand Microscopic Objects, tvitk RemarTcs on the Circulation in Animals and Plants, the Method ofvievoing Crystals by Polarized Light, S^c. &^c , forming a Guide for selecting and labelling subjects of Natural History, Botany ^ and Mineralogy for the Microscope. By Andrew Puitchard, Author of the ** Na- tural History of Animalcules," &c.&c. London. I2mo. Great attention has lately been paid to the improvement of the object glasses ofcompound microscopes, which have been brought to a high degree of perfection, and the microscope has in con- sequence become more than ever a popular instrument. Such re- searches as those of Leeuenhoeck, made with a single lens, require a patient, and even painful application of the powers of vision; these investigations of the minutiae of nature may now be pursued with comfort and safety, some important discoveries in the physio- logy of animals and vegetables have already been made in pursuing them, and many more may be with confidence expected. To those who possess microscopes this little work will be found to bean acceptable manual. The introductory observations contain some useful hints on preparing and mounting the objects; and as the price is very moderate, we recommend the purchase of two copies, one to cut up for labels for the slides, and one to be pre- served for reference. *^* . [ 297 ]. LI. Proceedings of Learned Societies. ROYAL SOCIETY. 1834. 'X'HE reading of a paper, entitled, ** On the Proofs of Dec. 18. — -■- a gradual Rising of the Land in certain parts of Sweden." By Charles Lyell, Esq., F.R.S., — was resumed, but not concluded. 1835. January 8. — On the Proofs of a gradual Rising of the Land in certain parts of Sweden. By Charles Lyell, Esq., F.R.S. An opinion has long been entertained that the waters of the Baltic, and even of the whole Northern Ocean, have been gradually sinking j and the purport of the present paper is, to communicate the obser- vations which the author made during the summer of 1S34, in refer- ence to this curious question. In his way to Sweden he examined the eastern shores of the Danish islands of Moen and Seeland, but neither there, nor in Scania, could he discover any indications of a recent rising of the land ; nor was there any tradition giving support to such a supposition. The first place he visited, where any elevation of land had been suspected, was Calmar j the fortress of which, built in the year 1030, appeared, on examination, to have had its founda- tions originally laid below the level of the sea, although they are now situated nearly two feet above the present level of the Baltic. Part of the moat on one side of the castle, which is believed to have been formerly filled with water from the sea, is now dry, and the bottom covered with green turf. At Stockholm, the author found many striking geological proofs of a change in the relative level of the sea and land, since the period when the Baltic has been inhabited by the Testacea which it now contains. A great abundance of shells of the same species were met with in strata of loam, &c., at various heights, from 30 to 90 feet above the level of the Baltic. They consist chiefly of the Cardium edule, the Tellina baltica, and the Littorina littoreus ; to- gether with portions of the MytUus edulis, generally decomposed, but often recognisable by the violet colour which they have imparted to the whole mass. In cutting a canal from Sodertelje to lake Maelar, several buried vessels were found ; some apparently of great antiquity, from the circumstance of their containing no iron, the planks being fixed together by wooden nails. In another place, an anchor was dug lip ; as also, in one spor, some iron nails. The remains of a square wooden house were also discovered at the bottom of an excavation made for the canal, nearly at a level with the sea, but at a depth of 64 feet from the surface of the ground. An irregular ring of stones was found on the floor of this hut, having the appearance of a rude fire-place, and within it was a heap of charcoal and charred wood. On the outside of the ring was a heap of junburnt fir wood, broken up as for fuel J the dried needles of the fir and the bark of the branches being still preserved. The whole building was enveloped in fine sand. The author next notices several circumstances regarding buildings in Stockholm and its suburbs, from which he infers that the elevation of the land, during the last three or four centuries, has not exceeded Third Series. Vol. 6. No. 34. Jpril 1835. 2 Q 298 Royal Society, certain narrow limits. At Upsala he met with the usual indications of a former elevation of the sea, from the presence of littoral shells of the same species as those now found in the Baltic. Certain plants, as the Glauca maritima and the Triglochin maritimus, which naturally inhabit salt marshes bordering the sea, flourish in a meadow to the south of Upsala ; a fact which corroborates the supposition that the whole of the lake Maelar and the adjoining low lands have, at no very remote period of history, been covered with salt water. The author examined minutely certain marks which had at different times been cut artificially in perpendicular rocks, washed by the sea, in various places ; particularly near Oregrund, Gefle, Lofgrund, and Edskosund ; all of which concur in showing that the level of the sea, when compared with the land, has very sensibly sunk. A similar con- clusion was deduced from the observations made by the author on the opposite, or western coast of Sweden, between Uddevalla and Gotenburg ; and especially from the indications presented by the islands of Orust, Gulholmen, and Marstrand. Throughout the paper a circumstantial account is given of the geo- logical structure and physical features of those parts of the country which the author visited : and the general result of the comparison he draws of both the eastern and western coasts and their islands, with the interior, is highly favourable to the hypothesis of a gradual rise of the land ; every tract having, in its turn, been first a shoal in the sea, and then, for a time, a portion of the shore. This opinion is strongly corroborated by the testimony of the inhabitants, (pilots and fishermen more especially,) of the increased extension of the land, and the apparent sinking of the sea. The rate of elevation, however, appears to be very different in difl'erent places : no trace of such a change is found in the South of Scania. In those places where its amount was ascertained with greatest accuracy, it appears to be about three feet in a century. The phaenomenon in question having ex- cited increasing interest among the philosophers of Sweden, and es- pecially in the mind of Professor Berzelius, it is to be hoped that the means of accurate determination will be greatly multiplied. January 15. — Second Essay on a general Method in Dynamics. By William Rowan Hamilton, Esq., Andrew's Professor of Astronomy in the University of Dublin, and Royal Astronomer of Ireland. Com- municated by Captain Beaufort, R.N., F.R.S. This essay is a sequel of the one which appeared in the last volume of the Philosophical Transactions, and which contained a general me- thod for reducing all the most important problems of dynamics to the study of one characteristic function, or one central or radical relation. It was there remarked that many eliminations required by this me- thod might be avoided by a general transformation, introducing the lime explicitly into a part (S) of the whole characteristic function (V) ; and the first object of the present essay is to examine and develope the properties of this part (S), which the author designates by the term Principal Function. This function is applied by the author to problems of perturbation, in which he finds it dispenses with many laborious and circuitous processes, and furnishes accurate expressions Royal Society, 299 of the disturbed configurations of a system by the rules of undisturbed motion, if only the initial components of velocities be changed in a suitable manner. Another manner of extending rigorously to dis- turbed, the rules of undisturbed motion, by the gradual variation of elements, in number double the number of the coordinates or other marks of position of the system, w^hich was first invented by Lagrange, and was afterwards improved by Poisson, is considered in this second essay under a form rather more general j and the general method of calculation which has already been applied by the author to other analogous questions in optics and in dynamics, is now applied to the integration of the equations which determine these elements. This general method is founded chiefly on a combination of the principle of variations with those of partial differentials, and may furnish, whea matured, a separate branch of analysis, which may be denominated the Calculus of Principal Functions. When applied to the integra- tion of the equations of varying elements, itsuggests the consideration of a certain Function of Elements, capable of being variously trans- formed, and which may be either rigorously determined, or at least approached to, by a corollary of the general method. With a view to illustrate these new principles, and more especially those connected with problems of perturbation, they are applied, in this essay, first, to a very simple example, suggested by the motions of projectiles, the parabolic path being treated as the undisturbed; and secondly, to the problem of determining the motions of a ternary or multiple system, with any laws of attraction or repulsion, and with one pre- dominant mass. This latter problem, which was touched upon in the former es.say, is here resumed in a new manner, by forming and in- tegrating the differential equations of a new set of varying elements, entirely distinct in theory (though little differing in practice) from the elements conceived by Lagrange; and having this advantage, that the differentials of all the new elements for both the disturbed and disturbing masses may be expressed by the coefficients of one disturbing function. An Account of the Eruption of Mount Etna in the year 1536, from an original cotemporary document, communicated in a letter to J. G. Children, Esq., Secretary of the Royal Society. By Sir Francis Palgrave, K.G.H., F.R.S. Record Office of the Treasury, Chapter House, Poets' Corner, Westminster, Jan. 14, 1835. Amongst various shreds and fragments of the correspondence from Italy dqring the period that Henry VIIL was negotiating with the Italian princes, is a document of a very different nature from the rest, being an extract from a letter written by the Barone di Burgis, dated at Palermo, 1 0th of April 1536, and giving an account of the then re- cent eruption of Mount Etna. ** Die xxiij. Martii, M. D. xxxvi., nocte, Mons Elhna qui nunc Mongibellus vocatur; facto, orientem versus, ostio, emisit materiam igneam, quae ad instar fluminis vagata est per octo miliaria in longi- tudine, et per unum miliare in latitudine ; ejus vero altitudo erat palmarum duodecim. Eadem nocte ignis extinctus est, et ubique 2 Q2 SOO Royal Society. remansit nigra materies praedictae altitudinis duodecim palmarum. Ig-' nis totam liquefecit nivem, quae ad instar rapidi torrentis tan to impetu defluit, ut domus, arbores, et quicquid obviam esset secum traheret. '* Sequentibusautem diebus scissa sunt aliaostia numero tredecim, quae miro strepitu ignem evomebant ad instar bombardarum j longe- que ab his per unum miliare cadebant ingentia saxa, quorum aliquot judicata sunt ponderis ultra quindecim cantanorum. Post slrepitum sequebatur odor sulphureus per aliquot miliaria in locis circumvicinis. Tantus erat impetus hujus igneae materiel, ut arbores prostraret et evelleret antequam eas tangerat, sique veterem materiem incendiorum praeteritorura sseculorum, offendebat, earn denuo incendebat. '* Ex quolibet ostio profluebant amplissimi rivi, qui aliquo in loco sua latitudine unum miliare occupabant, erantque altitudine duodecim palmarum. " Duravit hie ignis per sex dies, et singula quaque nocte aspicieba- tur in cacumine montis, ignis j die vero, fumus. *' Sed cognosci nequibat quem faceret effectum, quia illuc ascen- dere non licebat propter relictam materiem incendii." On the Electrical Relations of Metals and Metalliferous Minerals, By R. W. Fox, Esq. Communicated in a letter to Davies Gilbert, Esq., F.R.S. The author states that he has ascertained that the crystallized gray oxide of manganese holds a much higher place in the electro-magne- tic scale than any other body with which he has compared it, when immersed in various diluted acids, and alkaline solutions : he also gives a table of the order in which other metals and minerals stand in this respect. When employed in voltaic combinations he found that on being so arranged as to act in opposition to one another, the di- rection of the resultant of their action, as indicated by the deflection of the magnetic needle, did not coincide with the mean of the direc- tions of the needle when under the separate influence of each. Hence he infers that the needle is not a true index of the electricity trans- mitted; and that electro-magnetic action does not depend on a con- tinuous electric current. He conceives, therefore, that the phseno- mena are better explained on the hypothesis of pulsations which he formerly advanced. A galvanometer of a new construction is em- ployed by the author for weighing the deflecting force of these elec- trical impulses. On the Circulation of the Blood in Insects. By John Tyrrell, Esq., A.M. Communicated by P. M. Koget, M.D., Secretary to the Royal Society. The observations on the circulation of the blood in insects, which is a discovery of comparatively recent date, have been made almost exclusively on insects in the larva state ; but the author of the pre- sent paper details a variety of observations of the same fact in insects which had arrived at their last or perfect stage of development. Among the Myriapoda, the circulation was traced in the Geophilus, and still more distinctly in the Lithobiusforficatus. The author also detected the circulation, by the motion of globules, through the ner- vures of tlie wings of various perfect insects, namely, of some species Mr. Faraday's Ninth Series of Researches in Fdectricitij, 301 of the Hemerohius, Panorpa, Phryganea^ and Ephemeral and par- ticularly in the Musca dornestica, or common house-fly. The paper is accompanied by drawings of the appearances described. January 22. — A paper was read, entitled, ** Notes on the Temper- ature of the Air and the Sea, &c., made in a Voyage from England to India, in the Ship Hoogly, Capt. Reeves, in the year 1833." By Alexander Burnes, Esq., F.R.S. The observations contained in this communication are recorded in a tabular form, and show that the variations of the temperature of the sea accord very closely with those of the air, in all the latitudes which the author traversed in this voyage. A paper was then read, entitled, *• Remarks on certain Statements of Mr. Faraday, contained in the Fourth and Fifth Series of his Expe- rimental Researches in Electricity." By John Davy, M.D., F.R.S. Dr. Davy complains that Mr. Faraday has, in the paper referred to, made certain statements with respect to the opinions of Sir Humphry Davy relative to the conducting powers of dry nitre, and caustic pot- ash and soda, when in fusion by heat, and also with regard to other matters connected with voltaic electricity, which are not correct; and vindicates Sir Humphry Davy from the charge of want of perspicuity in the statement of his views of these subjects. A Note by Mr. Faraday on the preceding Remarks by Dr. Davy was then read, in which he replies to the charges there brought for- ward, and justifies those statements, the accuracy of which had been impugned by Dr. Davy. January 29. — The reading of a paper was commenced, entitled, ** Experimental Researches in Electricity. Ninth Series." By Michael Faraday, Esq., D.C.L., F.R.S. February 5. — Mr. Faraday's paper, entitled, " Experimental Re- searches in Electricity. Ninth Series," was resumed and concluded. In the series of experiments which are detailed in this paper, the author inquires into the causes of some remarkable phaenomena rela- ting to the action of an electric current upon itself, under certain cir- cumstances, whereby its intensity is highly exalted, and occasionally increased to ten, twenty, or even fifty times that which it originally possessed. For the production of this effect, the principal condition is that the current traverse a considerable length of a good conductor, such as a long wire j more especially if this wire be coiled in the form of a helix j and the effect is still further augmented when this helix is coiled round a cylinder of soft iron, constituting an electro-magnet. The evidence on which these conclusions are founded is the following. If an electromotor, consisting of a single pair of zinc and copper .plates, have these metals connected by a short wiredipping into cups of mercury, the electric spark consequent upon either forming or breaking the circuit is so slight as to be scarcely perceptible; but if a long wire be employed as the medium of connexion, a bright spark is obtained on breaking the contact. If the wire be coiled in a helix, the spark is still brighter j and if a core of soft iron be placed within the helix, the spark, at the moment of disjunction, is more brilliant than in any of the former cases : and the higher intensity of the cur- 302 Royal Society, rent is also manifested by the occurrence of a shock, at the same mo ment, to a person who grasps with wetted hands the two ends of the wire; whereas no such effect, nor even any sensible impression on the tongue, is produced by the electromotor, when a short wire is em- ployed. All these effects of exaltation are produced at a time when the ac- tual current of electricity from the electromotor is greatly diminished; as the author shows by many experiments on the ignition of a fine wire, and the deflection of a galvanometer. He also proves that the effects of the spark and the shock, at the moment of disjunction of a long wire, are due to a current far more powerful than that which passes through the short wire at the same instant ; or indeed than that which passes through either the long or the short wire at any other instant of time than when the disjunction takes place. That this extraordinary effect is not due to any species of inertia, is shown by the fact, that the same wire will produce it in a greater or less degree, under circumstances incapable of influencing any effect depending on inertia : thus, if 1 00 feet of wire, when extended, produce a certain effect, a greater effect will be produced by coiling the same wire into a helix, and a still more powerful one by employ- ing it as the helix of an electro-magnet. The author ultimately refers these phsenomena to an inductive ac- tion of the current, analogous, or perhaps identical, v/ith that described in the First Series of these Experimental Researches : for he found that when a second wire was placed parallel to the long conducting wire, the ends of this second wire being connected together so that a current of electricity could circulate round it, then the spark and shock did not take place at the first wire at the moment of disjunction, but a current was induced at the second wire, according to the law ori- ginally described in the First Series. The moment the current in the second wire was interrupted, the spark and shock appeared at the first. These and many other experiments were adduced to prove that these effects, namely, the shock and the spark, result from an in- ductive action of the original current, producing, at the noment it is stopped, a current, in the same direction as itself, in the same wire which serves to convey the original current. The author,lastly, considers the reverse effect produced upon mak- ing contact J and concludes his paper by some general views of the consequences resulting from this inductive action in various cases of electric discharge; pointing out the important influence it must have in magneto-electrical machines of the ordinary construction. The reading of a paper was then commenced, entitled, '* Geome- trical Researches concerning Terrestrial Magnetism." By Thomas Stephens Davies, Esq., F.R.S., &c. February 12. — Mr. Davies's paper, entitled "Geometrical Re- searches concerning Terrestrial Magnetism," was resumed and concluded. The object of this paper is to exhibit methods of conducting the mathematical inquiries which are applicable to the magnetism of the earth, by the aid of the coordinate geometry of three dimensions. lioyal Society, 305 When a point on the surface of the earth is given by means of its geographical coordinates, we can also refer it to any rectilinear co- ordinates that may be found convenient, and the transformations of the expressions can be made by known and familiar methods. Also, since at a given point the needle is deflected a measured quan- tity from the meridian plane, estimated on a tangent plane to the earth at the given point, and is also depressed another measured quan- tity below the same plane at that given point, its position is fixed by means of these measures. It will hence become capable of reference also to the same rectilinear coordinates as those into which the geo- graphical coordinates were transformed. The equation of the line, into which the dipping-needle disposes itself, becomes, therefore, ca- pable of expression in terms of the measured quantities above referred to J viz., the latitude, longitude, dip, and variation. The method of obtaining the constants which enter into the " equations of the nee- dle" as referred to the equator, a given meridian, and the meridian at right angles to it, are then detailed at length by the author j and these equations are calculated for six different places : fort Bowen, Boat Island, Chamisso Island, Valparaiso, Paris, and Paramatta. With a view to bring the hypothesis of the duality of the centres of magnetic force to a test, the author proceeds to reason, that as a free needle subjected to the action of only two poles, will always dispose it- self in the plane which passes through those poles and the centre of mo- tion of the needle, the needle prolonged will always intersect the mag- netic axis, or line which passes through the two poles. But when four straight lines are given in space, a fifth line (or rather two lines) can be so drawn as to intersect them all. If, therefore, we have the equations of four dipping-needles calculated from correct observations, we ought to be able to assign the equations of the two lines which rest upon them J one or other of which, in such case, will be the magnetic axis itself. This line ought to intersect every other needle j and hence the constants in its equations and the constants in the equations of any fifth needle ought to fulfill the algebraical test of intersection. The author has calculated the equations of the magnetic axis for the needles at Chamisso, Valparaiso, Paramatta, and Port Bowen, and made a comparison of it with the Paris needle. Instead of intersecting, the least distance between the said axis and needle is more than one 6th of the terrestrial radius; and hence, could the observations themselves be depended on, as being free from instrumental error and from local dis- turbances, the question of the duality of the centres of force would be at once settled in the negative ; but, as the opinions of those philo- sophers who are best acquainted with the dipping-needle are decidedly that the dipping-needle is not yet in such a condition as to induce implicit confidence in its indications, and as, moreover, the influence of geological and meteorological sources of disturbance are yet so far unappreciated as to enable us to correct the observations for them, the author hesitates to draw any positive conclusion from the results he has obtained. However, the results thus obtained, being the di- rect and legitimate deductive consequences of the observations, it is of course impossible by any other course of investigations which proceeds 304 Hoyal Society. from the same data, to draw a conclusion more to be depended on than this. The process he considers to be mathematically correct, as well as complete, and practicable 5 the question, as far as this test Is concerned, must remain open till satisfactory data can be obtained : and he proposes at the earliest period to resume the numerical dis- cussion of such observations as he may be able to procure. Mr. Davies remarks, that from the great labour of the calculations, he has been led to attempt a more brief method of examination by means of carefully executed geometrical constructions ; employing for that purpose the descriptive geometry, which has the advantage of bring- ing all the work to depend on the intersection of the hyperbola and straight line, situated upon the same plane. The resulting magnetic axes of the few cases he has constructed, though very far from coin- ciding, are yet positive in the same general region of the figure j and therefore the probability that their want of coincidence arises from erroneous and uncorrected observation is increased, and the impor- tance of a more extended and careful series of observations consider- ably augmented. Forthe purpose of examining the general character of the magnetical phaenomena which ought to result from the hypothesis of the duality of the poles, Mr. Davies proceeds to investigate the formulae which ex- press those phsenomena. These are, the magnetic equator, — the points at which the needle should become vertical, — the lines of equal dip, — the Halleyan lines, or lines of equal variation, — the isodynamic lines of Hansteen, — and the points at which the magnetic intensity, com- pared with the points immediately contiguous in all directions, is a maximum, or in other words, where the isodynamic lines are reduced to points. The first two of these only, are treated in the present paper ; the remaining ones will be the subject of a future memoir shortly to be submitted to the Society. The mathematical processes themselves scarcely admit of verbal description -, but the results of the investigation are briefly these. When the centres of force are situated within the sphere, there will be one only, or some even number of continuous lines on the surface of the earth, at any point of which the needle will be horizontal, ac- cording as the poles be of equal or unequal intensities. Whether the magnetic equator be determined with sufficient accuracy to assure us that there is but one such line, is a matter of considerable doubt; but if it should be admitted that it is, it oflVrs a strong confirmation of the strict analogy between the terrestrial and all other magnets with two poles, and thence an increasing confidence in all the other ana- logies conceived to exist between them. The points at which the needle is vertical are given by means of two equations, one of the fifth and the other of the second degree, and hence altogether there are ten such points theoretically possible. How many of these may be simultaneously real the equations do not, in their literal form, seem capable of determining ; but at all events they will, in all cases, bean even number, either 0, 2, 4, 6, 8, or 10. One having been determined, one other at least must exist in the actual circumstances of the terrestrial two-poled magnet. How many so Astronomical Socicti/, '305 ever such simultaneous points there may be, they must all lie in the same plane ; and hence, if the second point which must exist could be determined, then the great circle in the plane of which the axis of the magnet itself is situated would be determined 3 and thus another test would be afforded of the truth or error of the hypothesis itself. Mr. Davies suggests that as this plane will be symmetrical with respect to the phaenomena taking place on each side ot* it, its position might be tentatively assigned from a series of observations of those phaeno- mena, especially of the dip and intensity ; the variation being for ob- vious geometrical reasons excluded. Though the resulting formula does not in its literal form appear to be capable of decomposition into factors, yet from some considera- tions, chiefly analogical, Mr. Davies is led to hazard the conjecture that it is capable of such decomposition ; but as this is uncertain, he builds no consequences upon it, but leaves those consequences which would flow from it, open till it shall be discovered whether they would be justified by the conjecture itself being proved to be correct. A paper was also read, entitled, ** On certain Peculiarities in the double Refraction, and Absorption of Light, exhibited in the Oxalate of Chromium and Potash." By Sir David Brewster, K.H.,L.L.D., F.R.S. The crystals of the oxalate of chromium and potash are, generally speaking, opake; for at thicknesses not much greater than the 25th of an inch, they are absolutely impervious to the sun's rays, and their colour, seen by reflected light, is nearly black j but when powdered, they are green ; and the colour of the smaller crystals, viewed either by reflected or by transmitted daylight, is blue. One of the most remarkable of the properties of this salt is the difference of colour in the two images formed by double refraction. At a certain small thick- ness, the least refracted image is bright blue, and the most refracted image bright green. The blue is found by analysis with the prism to contain an admixture of green, and the green an admixture of red ; and by candlelight this red predominating over the green, gives the crystal a pink hue. At greater thicknesses the blue becomes purer and fainter, and the green passes into red ; and at a certain thickness the least refracted blue image disappears altogether, and the most refracted image is alone seen. At still greater thicknesses this image also disappears, and absolute opacity ensues. When the crystal is exposed to polarized light, with its axis in the plane of polarization, the transmitted light is green ; but when the axis is perpendicular to that plane, the transmitted light is blue. A solution of the salt ex- hibits the same general action upon light as the solid, with the excep- tion of double refraction. This salt has also the peculiar property of exciting a specific action upon a definite red ray, situated near the extremity of the red portion of the spectrum* ASTRONOMICAL SOCIETY. 1834. Dec. 12. — ^The President read a letter from His Royal High- ness the Duke of Sussex, acknowledging the vote of thanks passed * See our Number for January, p. 134. Third Scries. Vol.6. No. 34. April 1835. 2R 306 Astronomical Society, at the last meeting, and expressing interest in the welfare of the Society. The (olio wing communications were read : I. Some particulars of the Life of Dr. Halley. Communicated by Professor Rigaud, through Mr. Baily. The manuscript memoir, containing the particulars here alluded to, was found in the Bodleian Library, at Oxford j it is a small quarto, and consists of twenty leaves. The author is not known j but it appears that he was of Cambridge University, was acquainted with Halley and Dr. Sykes the orientalist, and wrote before Halley's manuscript ob- servations were out of the hands of his executors. As some of the circumstances therein mentioned are not generally known, the memoir was read as a sort of appendix to the paper communicated at the last meeting of the Society. It appears that it was Dr. Halley's intention, very early in life, to form a new catalogue of stars from actual ob- servation ; but finding that this ground was already occupied by He- velius and Flamsteed, he directed his attention to the southern hemi- sphere ; and under the sanction of His Majesty King Charles II., he was despatched to the island of St. Helena, furnished with the follow- ing instruments : An excellent brass sextant, of 5 J feet radius, well fitted up with telescope-sights, indented semicircles of the same me- tal, and screws for the ready bringing it into any plane j a quadrant of about 2 feet radius, which he intended chiefly for observations where- by to adjust his clock ; a telescope of 24 feet ; some lesser ones j two micrometers ; and a good pendulum-clock. He immediately, on his arrival at St. Helena, set himself to work; and from his observations deduced the catalogue of southern stars that was published in 1679. After some other journeys on the Continent, he returned to England ; and in 1 682 married Mrs. Mary Tooke. Intending now to settle some time at home, he resolved to pursue his astronomical observa- tions, and therefore fixed the sextant which he had at St. Helena in a small observatory which he had fitted up at Islington, where he car- ried on a regular course of observations (of the moon principally) from November 7, 1682, to June 16, 1684, the account of which is published at the end of Street's Astronomia Carolina. When the great recoinage of dipt money was made by King William III., five mints were erected, for that purpose, out of London : and Dr. Hal- ley was appointed comptroller of the mint at Cliester. In the year 1698, he was directed by His Majesty to proceed on a voyage for de- termining the law of the variation of the magnetic needle : and in the year 1701 he was instructed to make observations on the tides in the English Channel, and to take the bearings of the different head- lands on the coast. At the anniversary meeting of the Royal Society in November 1713, he was chosen secretary in the room of Sir Hans Sloane, who resigned that office : and on the decease of Mr. Flam- steed, at the close of the year 1719, he was recommended by the P2arl of Macclesfield, then lord chancellor, by the Earl of Sunderland, then secretary of state, and by others, as the fittest person to fill the office of Astronomer Royal ; to which situation he was appointed on Feb. 9, 1719-20, and which he held till the day of his death. Zoological Society, '307 Among the circumstances which are here recorded, and which are not very usually mentioned, if indeed they are known at all, are — that of Halley's appointment to the mint above mentioned — his having drawn up a synopsis of Newton's system for the use of James II., at the desire of the latter— ^hat his first voyage, by express direction, was meant to be one of discovery in the Southern Ocean — and that his acquaintance with Newton began about 1 684. II. Translation of a paper by Dr. Gibers in the AsLronomische ^aclirichten, No. 268, on the approaching return of Halley's comet. Translated andcommunicated by Mr. Galloway. This communication was given entire in our last Number, p. 45. HI. Observed Transits of the Moon and Moon-culminating Stars over the Meridian of Edinburgh Observatory, in October and Novem- ber, 1834, by Mr. Henderson. They are given in the Monthly No- tices. IV. Transits of the Moon with Moon-culminating Stars, observed at Cambridge Observatory in the month of November, ]834. Also given in the Monthly Notices. ZOOLOGICAL SOCIETV. 1834. Dec. 9. — The reading was concluded of a Paper entitled " Notes on the Natural History and Habits of the Omit horhynchus pa- radoxus, Blum.," by Mr. George Bennett, Corr. Memb. Z.S. ; in which the author gives a detailed account of his inquiries and researches on the subject in question, made in the Colony of New South Wales, and in the interior of New Holland, at the end of 1832 and com- mencement of 1833. He commences by a description of the exter- nal character of the animal, as observed by him in the living and recent state ; from which it appears that the greater or less degree of nakedness of the under surface of the tail is dependent on age, and is probably a result of the mode in which that organ trails upon the ground; that the colour of the upper mandible above, in an animal recently taken out of the water, is of a dull dirty greyish black covered with innumerable minute dots, and the under surface of the lower white in the younger specimens, and mottled in the more aged, while the inner surface of both is of a pale pink or flesh colour ; that the eyes are brilliant, and light brown ; and that the external orifices of the ears, which are with difficulty detected in dead specimens, are easily discoverable in the living, the animal ex- ercising the faculty of opening and closing them at will. When recent, and especially when wet, the Ornithorhynchus has a peculiar fishy smell, proceeding probably from an oily secretion. It is used as food by the Natives, by whom it is called, at Bathurst and Goul- burn Plains, and in the Yas, Murrumbidgee and Tumat countries, by the names of Mallangong or Tamhreet. Mr. G. Bennett is inclined to regard the two species usually described in modern books as not differing sufficiently from each other to justify their separation, and he therefore retains the name of Orn. paradoxus given to the animal by Professor Blumenbach, the universal adoption of which renders it inexpedient in this instance to recur to the older name 2 R 2 308 Zoological Society. of Platypus imposed on it by Shaw. He remarks on the distor- tions to which the exceedingly loose integuments are liable in the hands of staffers unacquainted with the characteristic features of the animal, and gives the general result of his measurements, in the recent state, of fifteen specimens shot and captured alive, as aver- aging in the males from 1 foot 7 to 1 foot 8 inches, and in the fe- males from 1 foot 6 to 1 foot 7 inches, in total length. One male specimen, shot near the Murrumbidgee River, measured 1 foot IH inches ; and a female, shot in the afternoon of the same day in the same part of the river, measured only 1 foot 4 inches. In these spe- cimens the relative proportions of the beak and tail were subject to considerable variation. Mr. G. Bennett's observations were commenced on the 4th of October 1832, at Mundoona in the Murray Country, on a part of the Yas River running through the estate of Mr. James Rose. The Water-Moles (as these animals are called by the Colonists,) chiefly frequent the open and tranquil parts of the stream, covered with aquatic plants, where the steep and shaded banks afford excellent situations for the excavation of their burrows. Such expanses of water are by the Colonists called " ponds." The animals may be readily recognised by their dark bodies just seen level with the sur- face, above which the head is slightly raised, and by the circles made in the water around them by their paddling action. On the slight- est alarm they instantly disappear ; and indeed they seldom remain longer on the surface than one or two minutes, but dive head fore- most with an audible splash, reappearing, if not alarmed, a short distance from the spot at which they dived. Their action is so rapid, and their sense of danger so lively, that the mere act of levelling the gun is sufficient to cause their instant disappearance ; and it is con- sequently only by watching them when diving, and levelling the piece in a direction towards the spot at which they seem likely to reappear, that a fair shot at them can be obtained. A near shot is absolutely requisite ; and when wounded they usually sink immedi- ately, but quickly reappear on the surface. A male specimen was shot, and brought out by the dog, on the following morning. In a few minutes it revived, and ran along the ground, instinctively endeavouring to regain the water, but did not survive more than twenty-five minutes. On this individual Mr. G. Bennett made various experiments, with the view of ascertaining the truth of the reports so extensively circulated of the injurious effects resulting from wounds inflicted by the spur. In no way, however, could he induce the animal to make use of its spurs as weapons of offence ; although in its struggles to escape, his hands were slightly scratched by the hind claws, and even, in consequence of the position in which he held it, by the spur also. The result of several subsequent repetitions of the experiment with animals not in a wounded state was the same. The natives, too, never seem fear- ful of handling the male Ornithorhynchus alive. On the evening of the same day a female was shot, which died almost immediately on being taken out of the water. In this speci- Mr. Bennett on the Natural History of the Ornithorhynchus. 309 men the mammary glands were scarcely obsen^able on dissection ; but the left uterus was found to contain three loose ova of the size of swan-shot. The right uterus was less enlarged, exhibited less vascularity, and contained no ova. Preparations of the generative organs of this individual, and of two other impregnated females which were subsequently obtained, were forwarded by the author to Mr. Owen, by whom they have been particularly described in the • Philosophical Transactions' for 1834, p. 555*. The next day three other specimens were shot : a male and two females. In the former the testes were found not to be larger than very small peas, and the same fact was observed in a specimen after- wards shot in the Murrumbidgee ; whereas in that first obtained, they were nearly of the size of pigeons' eggs. For this difference at the same season it seems difficult to account. The left uterus of one of the females was found to contain two ova, and that of the other a single ovum, of the size of buck-shot. As before, no ova were found in the right uterus. On the morning of the 7 th of October, Mr. G. Bennett pro^ ceeded, in company with a native, to the banks of the river to see the burrow of an Ornithorhynchus, from which the natives had taken the young during the previous summer. The burrow was situated on a steep part of the bank ; and its entrance, concealed among the long grass and other plants, was distant rather more than a foot from the water's edge. Its whole extent was not laid open, the natives contenting themselves with digging down upon it at stated distances, their operations being guided by the introduction into the burrow of a stick which indicated its direction. It took a serpentine course, and measured about twenty feet in length : the termination was broader than any other part, nearly oval in form, and strewed with dry river-weeds, &c. From this nest the native stated that he had taken in the previous season (December) three young ones, about six or eight inches in length, and covered with hair. In addition to the entrance above spoken of, the burrows have usually a second below the surface of the water, communicating with the interior just within the upper aperture. After exhibiting this burrow, the native proceeded to explain the means employed in tracking the Mallangongs. He pointed out on the moist clay of the banks foot-marks leading to a burrow, from the bottom of which, on inserting his arm, he drew forth some lumps of clay, which bore evident marks of the animal's recent passage. He declared, how- ever, that the inhabitant was absent, and Mr. G. Bennett was in- duced, by this information, to abstain from further investigation. A female specimen, shot in the evening of the same day, was found to have two ova, about the size of or rather smaller than buck-shot, in the left uterus ; and in this, as in all the other female specimens, much difficulty was experienced in finding the mammary glands. The contents of the cheek-pouches and stomachs always consisted of river insects, very small shell-fish, &c., comminuted and mingled ♦ An abstract of Mr. Owen*s paper was giren in our number for Janu- ary, pp.60, 61. - ^1 6 Zoological Society, < with mud or gravel, which latter, JMr. G. Bennett suggests, may be required to aid digestion. River-weeds were never observed to form part of the food; but Mr. George MacLeay informed the author that in a situation in which water-insects were very scarce he had shot Ornithorhynchi with river- weeds in their pouches. Similar excursions were made on the 8th and 9th of October ; and on the latter day one of the burrows was explored. The entrance of this burrow was situated on a moderately steep bank, abounding with long wiry grass and shrubs, at the distance of about five feet from the water's edge : its course lay in a serpentine direction up t})e bank, approaching nearer to the surface of the earth towards its termination. At this part it was expanded to form a chamber suf- ficiently capacious for the reception of the animal and her young, and measured one foot in length by six inches in breadth. Its whole length, from the entrance to the termination, was twenty feet ; narrowing as it receded from the entrance, where it measured one foot three inches in depth, and one foot one inch in breadth, and in the intermediate part becoming scarcely larger than the usual breadth of the animal when uncontracted. From this burrow a living female was taken, and placed in a cask, with grass, mud, water, &c. ; and in this situation it soon became tranquil, and apparently reconciled to its confinement. Hoping that he had now obtained the means, should his captive prove to have been impregnated, of determining the character of the excluded pro- duct, Mr. G. Bennett set out on his return for Sidney, on the 13tli of October, carrying the living Ornithorhynchus with him in a small box, covered with battens, between which only very narrow interv^als were left. The next morning, tying a long cord to its leg, he roused it and placed it on the bank of the river, in order to indulge it with a bathe ; and a similar indulgence was granted to it on the second day of its journey. On these occasions it soon found its way into the water, and travelled up the stream, apparently delighting in those places which abounded most with aquatic weeds. When diving in deej) and clear water, its motions were distinctly seen : it sank speedily to the bottom, swam there for a short distance, and then rose again to the surface. It appeared, however, to prefer keeping close to the bank, occasionally thrusting its beak into the mud, from whence it evidently procured food, as on raising the head, after withdrawing the beak, the mandibles were seen in lateral motion, as is usual when the animal masticates. The motions of the mandibles were similar to those of a duck under the same circumstances. After feeding, it would lie sometimes on the grassy bank, and at others partly in and partly out of the water, combing and cleaning its coat with the claws of the hind feet. This process occupied a considerable time, and greatly improved its sleek and glossy appearance. After its second excursion it was replaced in the box, which was not opened again until the following morning, when it was found to have made its escape. Although the summer season was now far advanced, Mr. G. Mr. Bennett on the Natural History of tJie Ornithorhynchus, 3 1 Iv Bennett determined to return to the interior and renew his investi- gations. On the 15th of November he again arrived at Mundoona, where he found that the river had fallen greatly, and sought in vain for the Water-Moles in the spots in which they had a few weeks be- fore been so abundantly seen. Some burrows were also examined, but without success. On the 21st he proceeded to Gadarigby, on the Murrumbidgee, where his exertions were more successful, seve- ral specimens being obtained ; but the only female shot was young and unimpregnated. On the 27th he returned to Mundoona^ where a female had been shot the previous day, the uterine organs of which afforded evidence that the young had been just produced. The abdominal glands were large, but no milk could be expressed from them ; the fur still covered the portion of integument on which its ducts terminated ; and there was no appearance of projecting nipple. No such projection was observed in any of the specimens in which the secretion of milk was demonstrable. Two other females were procured at the same place ; but both proved to be unimpreg- nated. On the 8th of December Mr. G. Bennett quitted Mundoona for the banks of the Murrumbidgee, and near Jugiong, on the latter river, had an opportunity of inspecting the burrow of an Ornithorhynchus, containing three young ones, which appeared to have not long pre- viously been brought forth. They were only thinly covered with hair and measured in length about H inch. No fragments of shells were observable in the burrow, nor anything that could lead to the supposition of the young having been excluded while yet in the egg. A want of spirit in which to preserve these interesting specimens unfortunately prevented their conveyance to Sidney. On the 28th of December the author visited apart of the WoUon- dilly River, in the neighbourhood of Goulburn Plains, called by the Natives Koroa, in order to explore the burrow of an Ornithorhyn- chus which had there been discovered. The termination of this bur- row was thirty-five feet from the entrance ; and Mr. G. Bennett states that burrows have been observed of even fifty feet in length. It was found to contain two young specimens, of the dimensions of 10 inches from the beak to the extremity of the tail. The nest consisted of dry river-weeds, the epidermis of reeds, and small dry fibrous roots, strewed over the floor of the terminal cavity. An old female was captured soon after on the banks of the river, in a ragged and wretched condition, which was conjectured to be the mother. But little milk could be pressed from her abdominal glands, as might have been expected in the parent of such well- grown young ones. She died at Mittagong, on the 1st of January, but the young ones sur- vived until some time after their arrival in Sidney. Mr. G. Bennett proceeds to describe in detail their habits in a state of captivity. Their various attitudes, when in a state of re- pose, are strikingly curious, and were illustrated by the exhibition of sketches made from the life. The young were allowed to run about the room : but the old one was so restless, and damaged the walls of the room so much by her attempts at burrowing, that it was found necessary to confine her to the box.. During the day she would 312 Geological Society. remain quiet, huddled up with her young ones ; but at night she became very restless, and eager to escape. The little ones were as frolicsome as puppies, and apparently as fond of play : and many of their actions were not a little ludicrous. During the day they seemed to prefer a dark corner for repose, and generally resorted to the spot to which they had been accustomed, although they would change it on a sudden apparently from mere caprice. They did not appear to like deep water, but enjoyed exceedingly a bathe in shal- low water, with a turf of grass placed in one corner of the pan : they seldom remained longer than ten or fifteen minutes in the water at one time. Though apparently nocturnal, or at least preferring the cool and dusky evening to the glare and heat of noon, their movements in this respect were so irregular as to furnish no grounds for a definite conclusion. They slept much, and it frequently hap- pened that one slept while the other was running about, and this occurred at almost all periods of the day. They climbed with great readiness to the summit of a bookcase, placing their backs against the wall and their feet against the bookcase ; and thus, by means of their strong cutaneous muscles and of their claws, mounting with much expedition to the top. Their food consisted of bread soaked in water, chopped e^^, and meat minced very small ; and they did not seem to prefer milk to water. One of the young ones died on the 29th of January 1833, and the other on the 2nd of February, having been kept alive in captivity for nearly five weeks. GEOLOGICAL SOCIETY. 1835. January 7th. — A letter from Dr. Bostock, F.G.S., addressed to George Bellas Greenoagh, Esq. P.G.S., containing an account of the analysis of a mineral water from the Island of St. Paul, in lat. 38° 45' S. and long. 77° 53' E., was first read. The island of St. Paul is stated, on the authority of Capt. Ford and Mr. Houslip, to be of volcanic origin, very rugged in its outline, and to have the form of a bowl, 10 or 12 miles in circumference, into which the sea flows by a narrow opening, capable of admitting a boat. The surface of the island is, in many places, covered with pumice, and at night flames were observed to issue from various crevices in the rocks. With the exception of the island of Amster- dam, about 40 miles to the north of it, St. Paul's is at a great distance from any land. In the hole from which the water was taken the thermometer stood at 212°. Dr. Bostock then explains the manner in which he conducted the examination, and gives the following as the earthy constituents of 100 grains of the water: Muriate of soda 2*3 grains. Sulphate of soda -053 Muriate of lime -340 Muriate of magnesia *059 Loss -038 2-790 Geological Society, 313 He afterwards compares these results with those obtained by Dr. Marcet from water procured from the middle of the South At- lantic J and from the great difference in the saline contents, infers that the water of the island of St. Paul is not merely the water of the neighbouring ocean in a state of dilution, or altered simply by mechanical filtration. A paper "On the chalk and flint of Yorkshire, compared with the chalk and flint of the southern counties of England," by James Mit- chell, LL.D., F.G.S., was then read. The chalk of Yorkshire, Dr. Mitchell states, is distinguished from that of the southern counties by its great hardness, by its being occasionally of a red colour*, by its being more distinctly stratified, and by its containing veins of calcareous spar. He says, that it is also distinguished by the upper part being always destitute of flints, while in the southern counties the absence of flints in the upper part is an exception. The flints of Yorkshire are shown to differ from those of the southern counties by their being almost invariably of a tabular form, constituting regulg,r and well-defined continuous layers ; by being tougher, and breaking into short small fragments, unfitted for the manufacture of gun flints ; by the colour being always greyish or whitish throughout the whole thickness ; the crust not being of a different character from the body of the flint. Nodules of iron pyri- tes are stated to be common in the Yorkshire chalk, but in that of the South of England to be confined to the lower chalk without flints. In conclusion the author points out the following resemblance between the Yorkshire chalk and that of the N.E. of Ireland, namely, the great hardness of both, and the common occurrence in both of iron pyrites and veins of calcareous spar. A letter was next read from Woodbine Parish, Esq., addressed to George Bellas Greenough, Esq., P.G.S., accompanying a suite of specimens from the neighbourhood of Bognor. The collection, referred to in this letter, contained a series of all the fossils hitherto described as occurring in the Bognor Rock, and a suite of specimens of Choanites Kcenigii obtained from the rolled shingle on the beach. Mr. Parish also points out for the first time the existence of chalk on the shore opposite Felpham, between high and low water mark. He states that it may be traced for upwards of a mile in the direction of Middleton j that at the point where it first appears, it is hard and thickly interspersed with flints, but that further on it becomes soft and the flints are less numerous. Mr. Parish procured from it many of the characteristic chalk fossils. He states also that near Middleton, chalk marl has been long dug at low water. A notice on the want of perpendicularity of the standing pillars of the Temple of Jupiter Serapis near Naples, by Capt. Basil Hall, R.N., F.G.S,, was afterwards read. Capt. Hall observes that the three pillars of the Temple of Serapis * See Phil. Mag. and Annals, N.S., vol. ix. p. 434. Third Series. Vol. 6. No. 34?. April 1835. 2 S 3 1 4 Geological Socielj/. now standing, each of which is formed of a single piece of stone, are not strictly perpendicular, but all slope towards the south-west, that is, towards the sea, and from the temple where the statue of Jupiter is supposed to have stood. It is well known the columns of ancient Greek temples, the Parthenon for instance, have an inclination in- wards. The slope of the columns in that of Serapis is not great, but very decided, and was established by measurement and by ob- servations on the angle formed by the reflection of the columns in the water, which covers the pavement of the temple at high tides. The floor of the temple is also slightly inclined, for Capt. Hall ob- served, that on the recession of the tide, the northern side was left dry, when the water was still some inches deep on the southern side. January 21. — A paper was first read " On an outlying basin of Lias on the borders of Salop and Cheshire, with a short account of the lower Lias between Gloucester and Worcester," by Roderick Impey Murchison, Esq., V.P.G.S. Having heard from Mr. Dod of Cleverly that frequent trials for coal had been made in a part of North Salop situated between the Hawkstone Hills and the towns of Whitchurch and Market Dray- ton, the author visited that district during the autumn of last year. He found that the strata, supposed to be coal shale, belong to the lias, and that they range over a considerable area resting upon red marl and new red sandstone. With the assistance of the Rev. T. Egerton, F.G.S., he has ascertained that this lias occupies an ellip- tical basin, the length of which from S. W. to N. E. is 10 miles, and the breadth about 4 to 6, the surrounding strata dipping inwards at slight angles. The western boundary only is indeterminable, being concealed by gravel and turf bog. The formation is divisible into marlstone and lower lias. The first is clearly exposed in the hill of Prees,and contains the fossils which characterize it in Gloucestershire and Worcestershire, viz., Avicula incEquivalvis, Gryphcsa gigantea, and Pecten cequivalvis, with an Ammonite, in great abundance, re- sembling A. geometricus of Phillips. The lower lias crops out at various points along the exterior of the ellipse, particularly between Moreton Mill and Burley Dam ; near the last of which places it is, in parts, bituminous and slaty, like the Kimmeridge coal. Near Cloverly and Adderley the lias shale has been penetrated by shafts in search of coal to the depth of 300 feet, and numerous fossils have been extracted, among which are, Ammonites Bucklandi, A.Conybeari, A.planicosta, A. planorbis, A, communis?, A. -, published in Zeiten's Wirtemberg fossils, and four species of undescribed Ammonites ; Astarteelegans, Belem- nites subclavatus (Voltz, found in the lias of Boll), Cidaris, Gryphcea incurva, G. MacCullochii, Modiola minima; Pecten and Pullastra (two unpublished species, both occurring at Brora); Plagiostoma pectinoideSj first published from Brora ; P. giganteum, Pentacrinites scalaris, Goldfuss; Rostellaria? Spirifer, Tellina, Unio, Turritella, and unpublished Serpulae ? Among these fossils some are universally characteristic of the formation, others were first observed in the lias of the distant di- Geological Society, 315 stricts of Brora in Scotland, and of Boll and Banz in Germany. Sorae of the sinkings produced small pieces of jet or lignite like that of Whitby j others nearer the escarpment went through the lias, and reached brine springs in the subjacent red marl. Having proved that this basin of lias reposes upon the new red sandstone, the author adverts to the almost unfathomable thickness of strata by which it must be separated from the coal-measures. Three fourths of this tract of lias are covered with thick accumulations of gravel, sand and boulders, the nature and origin of which will be pointed out on a subsequent occasion. With this sketch is connected an account of a new base line of the lower lias which the author has laid down upon the Ordnance map between Gloucester and Wor- cester. It crosses to the right bank of the Severn in the neighbour- hood of Tewkesbury, by Forthampton and Bushley, the lias occu pying Longden Heath as an outlier. The lowest strata of the for- mation are described as graduating into inferior green marls and white sandstone of the new red sandstone at Combe Hill, Bushley, Longden, Ripple, and Boughton Hill ; the characteristic strata a little above the line of junction being thin, flag-like beds of blue limestone and shale, characterized by Modiola Hillana, Ostreae, Spines of Echini, Gryphc^a gigantea, 8^c. SfC. This clear escarp- ment of the lower lias is of value, because the same strata are not well exposed in the coast sections at W^hitby and Lyme. A paper was afterwards read entitled, " A general view of the new red sandstone series, in the counties of Salop, Stafford, Wor- cester, and Gloucester." By Roderick Impey Murchison, Esq., V.P.G.S. Viewing the new red sandstone which occurs in parts of Salop^ Stafford, and Worcester, in the extended sense first applied to it by Mr. Conybeare*, as including all the deposits between the lias and the coal-measures, the author endeavours to divide the group into distinct subformations; an attempt which had not been made, the whole having been hitherto laid down upon maps as one for- mation. Following, as far as the structure of the country would allow, the divisions established by Professor Sedgwick for the N. E. of England, it is shown that the series is divisible into the under- mentioned subformations : Foreign Equivalents. 1. Red and green marls Keuper, 2. Sandstone and conglomer Ates, .Bunter sandstein, Gres bigarre, 3. Calcareous conglomerates. . . . Zechstein, S^c. 8^c. 4. Lower red sandstone Rothe todte liegende. \. ** Red and Green Marls J' — These are best developed in Glouces- tershire and Worcestershire, where they contain a subordinate white sandstone, undistinguishable from certain varieties of the Keuper- sandstone of the Germans. In the marls are situated most of the brine springs, both in these counties and in Salop and Cheshire, though some of them rise out of the inferior sandstone. But gyp- sum is not so abundantly developed as in the south-western districts * Outlines Geol. Cii^land and Wales, p. 278. 2S2 316 Geological Society, of England, occurring rarely, and in thin stripes. There is no trace of the '* niuschelkalk" beneath these marls, and they uniformly graduate downwards into sandstone. II. " Red Sandstone and Conglomerates !' — The country north of Shrewsbury affords the largest development of thick-bedded sand- stones, of grey and reddish colours, in the hills of Hawkstone,Wern, Grinshill, Nesscliff, &c. Ores of copper and manganese, with sulphate of strontian, and chalcedony are of partial occurrence. This group extends into Staffordshire and the east of Shropshire, where it contains many bands of quartzose conglomerates, the dis- integration of which gives a wild and sterile character to large tracts. In other parts, particularly north and south of Kidderminster, where the pure sandy beds prevail, are large districts of rye land, which exhibit an agricultural character quite distinct from that of any of the groups either above or below. In the southern parts of Worcestershire these red sandstones and conglomerates are con- cealed by a thick covering of gravel, and in Gloucester they are re- duced to a very narrow band. The division into thick beds, false lamination, and want of cohesion, are the characters of this group. III. ** Calcareous Conglomerates'' — In North Worcester and Salop calcareous conglomerates, forming natural escarpments and dipping beneath the above sandstones, are supposed to occupy the place of the dolomitic conglomerate of the south-west, or magnesian lime- stone of the north-east, of England. They are largely burnt for lime to the east of the Lickey and Clent Hills, where they are of irregular thicknesses. These strata are repeated at Enville, the Bowells, and at Coton, &c., between Kidderminster and Bridg- north. The chief imbedded fragments are of limestone, which at Coton and the Bowells being sometimes oolitic, are supposed to have been derived from Orelton and the Clee Hills. Fragments of old red sand- stone, quartz, and coal grits with impressions of plants, occur in the impure beds which pass into calcareous grits. This calca- reous conglomerate can only be partially detected in the red sand- stone of Apley, Nedge Hill and Lilleshall terraces, which form the eastern boundary of the coal-field of Coalbrook-dale ; and similar slender bands, around the Dudley coal-field, may possibly be com- posed of the same conglomerate. In the west of Shropshire these strata swell out into a distinct ridge of about two miles in length, extending from Cardeston to Alberbury, where they have been mentioned in previous abstracts by Professor Sedgwick* and by the author, and where they put on many of the characters of the dolomitic conglomerate and contain nests lined with crystals of dolomite. IV. <' Loiuer New Red Sandstone." — In Worcester and Salop the natural escarpment above alluded to exhibits sandstone and argilla- ceous marls, sometimes of great thickness, underlying the calcareous conglomerate. As these are seen in several places to pass down con- formably into the coal-measures, the author identifies them with the * Geol. Proceedings, vol. i. p. 345. Geological Society, 317- lower new red of the North of England, which Professor Sedgwick has shown to be the equivalent of the rothe todte liegende of German geologists. Such relations are seen in the eastern parts of the Lickey Hills, on the southern and eastern face of the coal-field of Coalbrook-dale, and in parts of the Shrewsbury coal-field. At Cantern bank near Bridgnorth and along a part of the bed of the Severn, these strata dip away conformably from the under- lying coal-measures. Similar relations are seen at Wellbatch near Shrewsbury, and still better at Coedway near Alberbury, where the red sandstones and shales graduate upwards into the dolomitic conglomerate, and downwards into coal-bearing strata. On the whole this subformation, containing sandstone, shale, and grits, has in some parts much the external appearance of the old red sandstone, and in others of the coal-measures, and impressions of plants have been found in it near Lilleshall and at Wellbatch. As coal has been extracted in many parts of the North of England from beneath sandstone of this age, the author speculates on the probability of similar success attending "well-regulated enterprises in Salop, Stafford, and Worcester. He alludes to a great sinking now going on between the edge of the Dudley coal-field and Bir- mingham, the shafts of which he believes are passing through strata of this age. The author has defined the whole of the base line of the new red sandstone from May Hill in Gloucestershire to the Oswestry coal- field, and has made some changes in its direction, particularly in the country between Newent and the Malvern Hills, and between Kidderminster and Bridgnorth. He further describes the occur- rence of several conglomerates along this base line, the most notable of which are Haffield Camp near Ledbury, Rosemary Rock near Knightwfck bridge on the eastern flanks of the Abberley Hills, and on the sides of Stagbury and Warshill Hills near Bewdley. These conglomerates, resembling that of Heavitrec in Devonshire, are subordinate to red sandstone, and the fragments of trap which they contain have been derived from hills in their immediate vicinity. Felspathic trap rocks of this character have been formerly described in the Malvern and Abberley Hills, and similar rocks have this year been discovered by the author in Stagbury and Warshill Hills resembling in composition the rocks of the Clent and Abberley Hills. The conglomerates, however, which rest upon their flanks, include fragments of quartz, greywacke, old red sandstone, &c. Though occupying the base line of the series of new red sandstone, the author does not pledge himself that the conglomerates of these districts are the precise equivalents of the lower red sand- stones which overlie and pass down into the coal-measures of Shropshire, for he shows that in the south of Worcestershire and in Gloucestershire there is not a sufficient expansion of the system to admit of such proofs. He is, however, disposed to think that the red sandstone which overlies the small patches of coal at Newent, may prove to be the representative of the lower new red. At two or three places on the eastern slopes of the Malvern Hills the conglo- 3 1 8 Intelligence and Miscellaneous Articles, '& merates have been observed in inclined positions, and at some height above the adjoining plain. At Great Malvern they adhere in one spot to the steep flank of the sienite in a dislocated form, dipping east at an angle of 30° to 35°. This fact not having been previously noticed is considered to be worthy of record, as leading to the in- ference, that this chain of trappean hills may have undergone a movement of elevation subsequent to the deposit of the new red sandstone. A letter was also read from Thomas Weaver, Esq. F.G.S. ad- dressed to George Bellas Greenough, Esq. P.G.S. In a communication read before the Society on the 4th of June 1830, Mr. Weaver stated that all the coal of the province of Mun- ster except that of the county of Clare, belonged to the transition series*. In this letter he says, " Having devoted between three and four months continuous service to further research in the south of Ireland, I have to retract that statement, having been led to too rapid an inference by the apparent connexion between the southern portion of the coal-field and the transition series ; and especially by finding the limestone, which there underlies the coal measures, to contain some fossils hitherto considered distinctive of the transition epoch, in particular the Trilobites, which I have designated, some crinoidal remains, &c. But having in my later researches discovered between that limestone (in a part of its extent) and the transition series, a well-characterized formation of old red sandstone, the anomaly disappears, and we have in regular succession, the old red .sandstone, carboniferous limestone, and the coal measures, which last I find also supported in other quarters by the carboniferous lime- stone, except where they directly conjoin the transition series. I am now, therefore, convinced that both the North and South Munster coal tracts are alone referrible to the great carboniferous order." LI I. Intelligetice and Miscellaneous Articles, PREPARATION OF CANTHARIDINE. M THIERRY procures this substance by the following process : • Reduce cantharides to powder, and digest it for some days either in aether, aetherized alcohol, or alcohol of sp. gr. '847 ; thesolution is to be separated, the residue washed with more alcohol, and the last portions of alcohol are to be displaced by water. The mixed liquors are to be subjected to distillation -, on cooling, numerous small crystals of cantharidine are deposited on the surface of the liquor. This liquor consists of two distinct portions ; the upper one is a green oil, which contains the crystallized cantharidine ; the lower one is a brown li- quor: they are separable by a funnel, and the oil mixed with can- tharidine is placed upon a filter, and when heated in a stove, the oil passes through the filter, and the cantharidine remains upon it. The cantharidine thus procured is still mixed with oil, which is to be sepa- rated by pressure between folds of paper ; the purification is com- pleted by dissolving the cantharidine in boiling alcohol, from which it * Phil. Mag. and Annals, N.S. vol. viii. p. 148. Intelligence and Miscellaneous Articles, 319 is deposited on cooling in the form of scales : the solution in alcohol, with the addition of animal charcoal, is to be repeated. Cantharidine thus obtained has the following properties : It is ino- dorous ^ when heated to 400° Fahr. it melts ^ and if the heat be con- tinued, it is converted into white vapours, which condense in small crystals on the sides of the vessel. Concentrated and boiling sulphuric acid dissolves cantharidine j the solution has a light brown colour : when diluted with water, it depo- sits cantharidine in small needles. Boiling nitric acid dissolves it without any change of colour j the solution deposits small crystals on cooling, and the same effect is produced by muriatic acid. Potash and soda dissolve cantharidine ; and if concentrated acetic acid be added to these solutions, the cantharidine is deposited in small crystals. Ammonia has no action on cantharidine. Oil of turpentine, olive oil, and oil of sweet almonds dissolve can- tharidine when hot, but it deposits on cooling. — Journal de Chimie MMcale, Mars 1835. GALLIC ACID SPEEDILY PREPARED. According to Dobereiner, gallic acid may be prepared by mixing a concentrated infusion of galls with acetic acid, in order to decompose the gallate of lime ; it is then to be shaken for a few minutes with aether, which takes up much gallic acid ; the aether is to be slowly evaporated, and gallic acid is obtained in a very short time in small colourless crystals.. — Ibid. PRESERVATION OF DELIQUESCENT SALTS. M. Druchar recommends that a few drops of oil of turpentine should be put into the bottle, and when it is diffused the deliquescent crystals should be introduced. — Ibid. COMPOSITION OF THE ATMOSPHERE. M. A. Chevallier is at present occupied with researches on the composition of the atmosphere j he states the following as the results already obtained : 1st. In general, the air of Paris and of many other places contains ammonia and organic matters in solution. 2ndly. If the water deposited from air (dew) by cooling be exanjined, it is found to contain ammonia and organic matters. 3rdly. The quantity of ammonia contained in the air is often pretty considerable. 4thly. The presence of ammonia is easily explained, because this gas is produced under many circumstances. 5thly. The composition of atmospheric air may vary in certain lo- calities, from a great number of particular circumstances, as the nature of the combustible employed in great masses, the decomposition of animal and vegetable matters, &c.&c. The air of London contains sul- phurous acid, that of the sewers of Paris contains acetate and hydro- sulphuret of ammonia j air taken from near the bassinsde Montfau^on contains ammonia and its hydrosulphuret. — Journal de Pliarmacie, Nov. 1834. •^^^ ^•§:£ c^fi.a . ^ . S "Si ^ >4 qJ ,tf J. fe >> >> bl « « tXC « fr< (^ ■< - t S > "^52 3 ^ -rT. .. <^ 3 ii !S > -^^ O cf^-3 ..0)2 c^ S *^ .ti !ii '~' 3 ■«f o -2 ^-d "O V 9J S ' oj 3 13 a3 - O 0) c H'T305m .. O P< 05 I ■3 3 2 MM 5 01 (N 2 isog • O • • "OO^O • puoq : ; •'sogl^ ^ g:--=-= I ^ I ^ s^-^-i Sf'-p 6:' ^' 13 ^' ^' i St' I '^ S* ^ i i | i i ^ Sf* S^ S^ g s s s . s . .. s .. puoT i i^ ^ i ^ ^ i i i i, t i i ^ i i ^ ^ i ^^ i^ ^ i i. ^ ^ tt nsog ID u^c^a^r>.c^»jr5r^OO^'-^tOTf ip in »p »p PQoo U'" ^O fC ^'i ■^ ON i—* C«C«CICJ(M COr;^Q-^-*OOvoTt^C<«Q0O0»'^» t^*OOt^ONOCp»pr^yl'OOtor^oioococp'-^o >-i-'0 — ^0-^o^ooOT* atom water (by theory) ...J [To be continued.] LVI. Experimental Researches in Electricity. — Eighth Se- ries. By Michael Faraday, D.C.L.F.R.S.Fullerian Prof. Chem, Royal Institution, Corr. Memh. Royal and Imp. Acadd. of Sciences, Paris, Petershurgh, Florence, Copenhagen, Ber- tin, 6)C. Sfc. [Continued from p. 279.] f iii. On associated Voltaic Circles, or the Voltaic Battery. 989. "PASSING from the consideration of single circles -■• (875. &c.) to their association in the voltaic battery, it is a very evident consequence, that if matters are so arranged Qjiantity of Electricity not increased withNumher of Plates, 335 that two sets of affinities, in place of being opposed to each other as in figg. 1, 4. (880. 891.)j are made to act in con- formity, then, instead of either interfering with the other, it will rather assist it. This is simply the case of two voltaic pairs of metals arranged so as to form one circuit. In such ar- rangements the activity of the whole is known to be increased, and when ten, or a hundred, or any larger number of such alternations are placed in conformable association with each other, the power of the whole becomes proportionably exalted, and we obtain that magnificent instrument of philosophic re- search, the voltaic battery. 990. But it is evident from the principles of definite action already laid down, that the quantity of electricity in the cur- rent cannot be increased with the increase of the quantity of metal oxidized and dissolved at each new place of chemical, action. A single pair of zinc and platina plates throws as much electricity into the form of a current, by the oxidation of 32*5 grains of the zinc (868.) as would be given by the same alteration of a thousand times that quantity, or nearly five pounds of metal oxidized at the surface of the zinc plates of a thousand pairs placed in regular battery order. For it is evident, that the electricity which passes across the acid from the zinc to the platina in the first cell, and which has been associated with, or even originated by, the decomposition of a definite portion of water in that cell, cannot pass from the zinc to the platina across the acid in the second cell, without the decomposition of the same quantity of water there, and the oxidation of the same quantity of zinc by it (924'. 949.). The same result recurs in every other cell; the electro-chemical equivalent of water must be decomposed in each,before the cur- rent can pass through it; for the quantity of electricity passed, and the quantity of electrolyte decomposed, must be the equiva- lents of each other. The action in each cell, therefore, is not to increase the quantity set in motion in any one cell, but to aid in urging forward that quantity, the passing of which is consistent with the oxidation of its own zinc ; and in this way it exalts that peculiar property of the current which we endea- vour to express by the term intensity, without increasing the quantity beyond that which is proportionate to the quantity of zinc oxidized in any single cell of the series. 991. To prove this, 1 arranged ten pairs of amalgamated zinc and platina plates with dilute sulphuric acid in the form of a battery. On completing the circuit, all the pairs acted and evolved gas at the surfaces of the platina. This was col- lected and found to be alike in quantity for each plate ; and the quantity of hydrogen evolved at any one platina plate was 336 Dr. Faraday's Experimental Reseaj-ches in Electricity. in the same proportion to the quantity of metal dissolved from any one zinc plate, as was given in the experiment with a single pair (864?. &c.). It was therefore certain, that, just as much electricity and no more had passed through the series of ten pair of plates as had passed through, or would have been put into motion by, any single pair, notwithstanding that ten times the quantity of zinc had been consumed. 992. This truth has been proved also long ago in another way, by the action of the evolved current on a magnetic needle; the deflecting power of one pair of plates in a battery being equal to the deflecting power of the whole, provided the wires used be sufficiently large to carry the current of the single pair freely; but the cause of this equality of action could not be understood whilst the definite action and evolu- tion of electricity (783. 869.) remained unknown. 993. The superior decomposing power of a battery over a single pair of plates is rendered evident in two ways. Elec- trolytes held together by an affinity so strong as to resist the action of the current from a single pair, yield up their ele- ments to the current excited by many pairs ; and that body which is decomposed by the action of one or of few pairs of metals, &c., is resolved into its ions the more readily as it is acted upon by electricity urged forward by many alterna- tions. 994. Both these effects are, I think, easily understood. Whatever intensity may be, (and that must of course depend upon the nature of electricity, whether it consist of a fluid or fluids, or of vibrations of an s&ther, or any other kind or con- dition of matter,) there seems to be no difficulty in compre- hending that the degree of intensity at which a current of electricity is evolved by a first voltaic element, shall be in- creased when that current is subjected to the action of a se- cond voltaic element, acting in conformity and possessing equal powers with the first : and as the decompositions are merely opposed actions, but exactly of the same kind as those which generate the current (917.)j it seems to be a natural consequence, that the affinity which can resist the force of a single decomposing action shall be unable to oppose the ener- gies of many decomposing actions, operating conjointly, as in the voltaic battery. 995. That a body which can give way to a current of feeble intensity should give way more freely to one of stronger force, and yet involve no contradiction to the law of definite elec- trolytic action, is perfectly consistent. All the facts and also the theory I have ventured to put forth, tend to show that the act of decomposition opposes a certain force to the passage of Waste of Electric Power hy the Use of ordinary Zinc. 337 the electric current ; and that this obstruction should be over- come more or less readily, in proportion to the greater or less intensity of the decomposing current, is in perfect consistency with all our notions of the electric agent. 996. I have elsewhere (947.) distinguished the chemical action of zinc and dilute sulphuric acid into two portions; that which, acting effectually on the zinc, evolves hydrogen at once upon its surface, and that which, producing an arrangement of the chemical forces throughout the electrolyte present, (in this case water,) tends to take oxygen from it, but cannot do so unless the electric current consequent thereon can have free passage, and the hydrogen be delivered elsewhere than against the zinc. The electric current depends altogether upon the second of these ; but when the current can pass, by favouring the electrolytic action it tends to diminish the former and increase the latter portion. 997. It is evident, therefore, that when ordinary zinc is used in a voltaic arrangement, there is an enormous waste of that power which it is the object to throw into the form of an electric current; a consequence which is put in its strongest point of view when it is considered that three ounces and a half of zinc, properly oxidized, can circulate enough electri- city to decompose nearly one ounce of water, and cause the evolution of about 2400 cubic inches of hydrogen gas. This loss of power not only takes place during the time the elec- trodes of the battery are in communication, being then pro- portionate to the quantity of hydrogen evolved against the surface of any one of the zinc plates, but includes also all the chemical action which goes on when the extremities of the pile are not in communication. 998. This loss is far greater with ordinary zinc than with the pure metal, as M. de la Rive has shown *. The cause is, that when ordinary zinc is acted upon by dilute sulphuric acid, portions of copper, lead, cadmium, or other metals which it may contain, are set free upon its surface ; and these, being in contact with the zinc, form small but very active voltaic circles, which cause, great destruction of the zinc and evolu- tion of hydrogen, apparently upon the zinc surface, but really upon the surface of these accidental metals. In the same pro- portion as they serve to discharge or convey the electricity back to the zinc, do they diminish its power of producing an electric current which shall extend to a greater distance across the acid, and be discharged only through the copper or pla- • Quarterly Journal of Science, 1831, p. 388; ov BibliothequeUniver seller 1830, p. 391.' [Also Phil. Mag. and Annals, N.S., vol. viii. p. 298.~Edit.] Third Series. Vol. 6. No. 35. May 1835. \ 2 X 338 Dr. Faradjiy'b Experimental Researches in Electricity, tina plate which is associated with it for the purpose of form- ing a voltaic apparatus. 999. All these evils are removed by the employment of an amalgam of zinc in the manner recommended by Mr. Kemp*, or the use of the amalgamated zinc plates of Mr. Sturgeon (863.), who has himself suggested and objected to their appli- cation in galvanic batteries ; for he says, " Were it not on ac- count of the brittleness and other inconveniences occasioned by the incorporation of the mercury with the zinc, amalgama- tion of the zinc surfaces in galvanic batteries would become an important improvement ; for the metal would last much longer, and remain bright for a considerable time, even for several successive hours ; essential considerations in the em- ployment of this apparatusf." 1000. Zinc so prepared, even though impure, does not sensibly decompose the water of dilute sulphuric acid, but still has such affinity for the oxygen, that the moment a metal which, like copper or platina, has little or no affinity, touches it in the acid, action ensues, and a powerful and abundant electric current is produced. It is probable that the mercury acts by bringing the surface, in consequence of its fluidity, into one uniform condition, and preventing those differences in character between one spot and another which are necessary for the formation of the minute voltaic circuits referred to (998.). If any difference does exist at the first moment, with regard to the proportion of zinc and mercury, at one spot on the surface^ as compared with another, that spot having the least mercury is first acted on, and, by solution of the zinc, is soon placed in the same condition as the other parts, and the whole plate rendered superficially uniform. One part cannot, therefore, act as a discharger to another ; and hence all the chemical power upon the water at its surface is in that equa- ble condition (94?9.), which, though it tends to produce an electric current through the liquid to another plate of metal which can act as a discharger (950.), presents no irregularities by which any one part, having weaker affinities for oxygen, can act as a discharger to another. Two excellent and im- portant consequences follow upon this state of the metal. The first is, that \k\Qfull equivalent of electricity is obtained for the oxidation of a certain quantity of zinc ; the second, that a bat- tery constructed with the zinc so prepared, and charged with ♦ Jameson's Edinburgh Journal, October 1828. t Recent Experimental Researches, p. 42, &c. Mr. Sturgeon is of course unaware of the definite production of electricity by chemical ac- tion, and is in fact quoting the experiment as the strongest argument against the chemical theory of galvanism. Voltaic Battery of amalgamated Zinc, 339 dilute sulphuric acid, is active only whilst the electrodes are connected, and ceases to act or be acted upon by the acid the instant the communication is broken. JOOl. I have had a small battery often pairs of plates thus, constructed, and am convinced that arrangements of this kind will be very important, especially in the development and il- lustration of the philosophical principles of the instrument. The metals I have used are amalgamated zinc and platina, connected together by being soldered to platina wires, the whole apparatus having the form of the couronne des tasses. The liquid used was dilute sulphuric acid of sp. gr. 1*25. No action took place upon the metals except when the electrodes were in communication, and then the action upon the zinc was only in proportion to the decomposition in the experimental cell ; for when the current was retarded there, it was retarded also in the battery, and no waste of the powers of the metal was incurred. 1002. In consequence of this circumstance, the acid in the cells remained active for a very much longer time than usual* In fact, time did not tend to lower it in any sensible degree ; for whilst the metal was preserved to be acted upon at the proper moment, the acid also was preserved almost at its first strength. Hence a constancy of action far beyond what can be obtained with the use of common zinc. 1003. Another excellent consequence was the renewal, du- ring the interval of rest between two experiments, of the first and most efficient state. When an amalgamated zinc and a platina plate, immersed in dilute sulphuric acid, are first con- nected, the current is very powerful, but instantly sinks very much in force, and in some cases actually falls to only an eighth or a tenth of that first produced (1036.). This is due to the acid which is in contact with the zinc becoming neutral- ized by the oxide formed; the continued quick oxidation of the metal being thus prevented. With ordinary zinc, the evolution of gas at its surface tends to mingle all the liquid together, and thus bring fresh acid against the metal, by which the oxide formed there can be removed. With the amalga- mated zinc battery, at every cessation of the current, the sa- line solution against the zinc is gradually diffused amongst the rest of the liquid ; and upon the renewal of the contact, with the electrodes, the zinc plates are found most favourably circumstanced for the production of a ready and powerful current. 1004. It might at first be imagined that amalgamated zinc would be much inferior in force to common zinc, because of the lowering of its energy, which the mercury might be sup- 2X2 340 Dr. Faraday's Experimental Researches in Electricity, posed to occasion over the whole of its surface ; but this is not the case. When the electric currents of two pairs of platina and zinc plates were opposed, the difference being that one of the zincs was amalgamated and the other not, the current from the amalgamated zinc was most powerful, although no gas was evolved against it, and much was evolved at the sur- face of the unamalgamated metal. Again, as Davy has shown*, if amalgamated and unamalgamated zinc be put in contact, and dipped into dilute sulphuric acid, or other exciting fluids, the former is positive to the latter, i. e. the current passes from the amalgamated zinc, through the fluid, to the unpre- pared zinc. This he accounts for by supposing that " there is not any inherent and specific property in each metal which gives it the electrical character, but that it depends upon its peculiar state — on that form of aggregation which fits it for chemical chancre." 1005 The superiority of the amalgamated zinc is not, how- ever, due to any such cause, but is a very simple consecjuence of the state of the fluid in contact with it; for as the unpre- pared zinc acts directly and alone upon the fluid, whilst that which is amalgamated does not, the former (by the oxide it produces) quickly neutralizes the acid in contact with its sur- face, so that the progress of oxidation is retarded, whilst, at the surface of the amalgamated zinc, any oxide formed is in- stantly removed by the free acid present, and the clean me- tallic surface is always ready to act with full energy upon the water. Hence its superiority (1037.). 100(5. The progress of improvement in the voltaic battery and its applications, is evidently in the contrary direction at present to what it was a few years ago ; for in place of in- creasing the number of plates, the strength of acid, and the extent altogether of the instrument, the change is rather towards its first state of simplicity, but with a far more inti- mate knowledge and application of the principles which govern its force and action. Effects of decomposition can now be obtained with ten pairs of plates (4? 17.), which required five hundred or a thousand pairs for their production in the first instance. The capability of decomposing fused chlorides, iodides, and other compounds, according to the law before established (380. &c.), and the opportunity of collecting cer- tain of the products, without any loss, by the use of apparatus of the nature of those already described (789. 814. &c.), ren- der it probable that the voltaic battery may become a useful and even oeconomical manufacturing instrument; for theory evidently indicates that an equivalent of a rare substance may * Philosophical Transactions, 1826, p. 405. [or Phil. Mag. and Annals, N.S„ vol. i. p. 102.— Edit] Retarding Effects of interposed Plates. 341 be obtained at the expense of three or four equivalents of a very common body, namely, zinc : and practice seems thus far to justify the expectation. In this point of view I think it very likely that plates of platina or silver may be used instead of plates of copper with advantage, and that then the evil arising occasionally from solution of the copper, and its pre- cipitation on the zinc, (by which the electro-motive power of the zinc is so much injured,) will be avoided (1047.)- f iv. On the Resistance of an Electrolyte to Electrolytic Action^ and on Interpositions, 1007. I have already illustrated, in the simplest possible form of experiment (891. 910.), the resistance established at the place of decomposition to the force active at the exciting place. I purpose examining the effects of this resistance more generally; but it is rather with reference to their practical inter- ference with the action and phaenomena of the voltaic battery, than with any intention at this time to offer a strict and phi- losophical account of their nature. Their general and prin- cipal cause is the resistance of the chemical affinities to be overcome; but there are numerous other circumstances which have a joint influence with these forces (10S4. 1040. &c.), each of which would require a minute examination before a correct account of the whole could be given. 1008. As it will be convenient to describe the experiments in a form different to that in which they were made, both forms shall first be explained. Plates of platina, copper, zinc, and other metals, about three quarters of an inch wide and three inches long, were associated together in pairs by means of platina wires to which they were soldered, (Plate I.) fig. 16, the plates of one pair being either alike or different, as might be required. These were arranged in glasses, fig. 17, so as to form Volta's crown of cups. The acid or fluid in the cups never covered the whole of any plate : and occasionally small glass rods were put into the cups, between the plates, to pre- vent their contact. Single plates were used to terminate the series and complete the connexion with a galvanometer, or with a decomposing apparatus (899. 968. &c.), or both. Now if fig. 18 be examined and compared with fig. 19, the latter may be admitted as representing the former in its simplest condition; for the cups i, ii, and iii of the former, with their contents, are represented by the cells i, ii, and iii of the latter, and the metal plates Z and P of the former by the similar plates represented Z and P in the latter. The only difference, in fact, between the apparatus, fig. 18, and the trough repre- sented fig. 19, is that twice the quantity of surface of contact 342 Dr. Faraday's Experimental Researches in Electricity. between the metal and acid is allowed in the first to what would occur in the second. 1009. When the extreme plates of the arrangement just described, fig. 18, are connected metallically through the galvanometer g, then the whole represents a battery consisting of two pairs of zinc and platina plates urging a current for- ward, which has, however, to decompose water unassisted by any direct chemical affinity before it can be transmitted across the cell iii, and therefore before it can circulate. This de- composition of water, which is opposed to the passage of the current, may as a matter of convenience be considered as taking place either against the surfaces of the two platina plates which constitute the electrodes in the cell iii, or against the two surfaces of that platina plate which separates the cells ii and iii, fig. 19, from each other. It is evident that if that plate were away, the battery would consist of two pairs of plates and two cells, arranged in the most favourable position for the production of a current. The platina plate therefore, which being introduced as at x, has oxygen evolved at one surface and hydrogen at the other (that is, if the decomposing current passes), may be considered as the cause of any ob- struction arising from the decomposition of water by the elec- trolytic action of the current; and I have usually called it the interposed plate. 1010. In order to simplify the conditions, dilute sulphuric acid was first used in all the cells, and platina for the inter- posed plates ; for then the initial intensity of the current which tends to be formed is constant, being due to the power which zinc has of decomposing water; and the opposing force of de- composition is also constant, the elements of the water being unassisted in their separation at the interposed plates by any affinity or secondary action at the electrodes (744.), arising either from the nature of the plate itself or the surrounding fluid. 1011. When only one voltaic pair of zinc and platina plates were [was] used, the current of electricity was entirely stopped to all practical purposes by interposing one platina plate, fig. 20, i. e. by requiring of the current that it should decompose water, and evolve both its elements, before it should pass. This consequence is in perfect accordance with the views be- fore given (910. 917. 973.). For as the whole result depends upon the opposition of forces at the places of electric excite- ment and electro-decomposition, and as water is the substance to be decomposed at both before the current can move, it is not to be expected that the zinc should have such powerful attraction for the oxygen, as not only to be able to take it from Retardation jn-oduced by interposed Plates. 343 its associated hydrogen, but leave such a surplus of force as, passing to the second place of decomposition, should be there able to effect a second separation of the elements of water. Such an effect would require that the force of attraction be- tween zinc and oxygen should under the circumstances be at least twice as great as the force of attraction between the oxy- gen and hydrogen. 1012. When two pairs of zinc and platina exciting plates were used, the current was also practically stopped by one interposed platina plate: fig. 21, There was a very feeble effect of a current at first, but it ceased almost immediately. It will be referred to, with many other similar effects, here- after (1017.)- 1013. Three pairs of zinc and platina plates, fig. 22, were able to produce a current which could pass an interposed platina plate, and effect the electrolyzation of water in cell iv. The current was evident, both by the continued deflexion of the galvanometer, and the production of bubbles of oxygen and hydrogen at the electrodes in cell iv. Hence the accu- mulated surplus force of these plates of zinc, which are active in decomposing water, is more than equal, when added to* gether, to the force with which oxygen and hydrogen are combined tin water, and is sufficient to cause the separation of these elements from each other. 1014. The three pairs of zinc and platina plates were now opposed by two intervening platina plates, fig. 23. In this case the current was stopped. 1015. Four pairs of zinc and platina plates were also neu- tralized by two interposed platina plates, fig. 24. 1016. Five pairs of zinc and platina, with two interposed platina plates, fig. 25, gave a feeble current ; there was per- manent deflexion at the galvanometer, and decomposition in the cells vi and vii. But the current was very feeble ; very much less than when all the intermediate plates were removed and the two extreme ones only retained ; for when they were placed six inches asunder in one cell, they gave a powerful current. Hence five exciting pairs, with two interposed obstructing plates, do not give a current at all comparable to that of a single unobstructed pair. 1017. I have already said that a very feeble current passed when the series included one interposed platina and two pairs of zinc and platina plates ( 1012.). A similarly feeble current passed in every case, and even when only one exciting pair and four intervening platina plates were used, fig. 26, a current passed which could be detected at j:, both by chemical action on the solution of iodide of potassium, and by the galvano- 844? Dr. F{iraday*s Experimental Researches in Electricitif, meter. This current I believe to be due to electricity reduced in intensity below the point requisite for the decomposition of water (970. QS^.); for water can conduct electricity of such low intensity by the same kind of power which it possesses in common with metals and charcoal, though it cannot conduct electricity of higher intensity without suffering decomposition, and then opposing a new force consequent thereon. With an electric current under this intensity, it is probable that in- creasing the number of interposed platina plates would not involve an increased difficulty of conduction. 1018. In order to obtain an idea of the additional interfer- ing power of each added platina plate, six voltaic pairs and four intervening platinas were arranged as in fig. 27 ; a very feeble current then passed (985. 1017.). When one of the platinas was removed so that three intervened, a current somewhat stronger passed. With two intervening platinas a still stronger current passed : and with only one intervening platina a very fair current was obtained. But the effect of the successive plates, taken in the order of their interposition, was very different, as might be expected ; for the first re- tarded the current more powerfully than the second, and the second more than the third. 1019. In these experiments both amalgamated and un- amalgamated zinc were used, but the results generally were the same. 1020. The effects of retardation just described were altered altogether when changes were made in the nature of the liquid used between the plates, either in what may be called the ex- citing or the retarding cells. Thus, retaining the exciting force the same, by still using pure dilute sulphuric acid for that purpose, if a little nitric acid were added to the liquid in the retarding cells, then the transmission of the current was very much facilitated. For instance, in the experiment with one pair of exciting plates and one intervening plate (1011.), fig. 20, when a few drops of nitric acid were added to the contents of cell ii, then the current of electricity passed with considerable strength (though it soon fell from other causes (1036. 104<0.),) and the same good effect was produced by the nitric acid when many interposed plates were used. 1021. This seems to be a consequence of the diminution of the difficulty of decomposing water when its hydrogen, as in these cases, instead of being absolutely expelled, is transferred to the oxygen of the nitric acid, producing a secondary result at the cathode (752.) ; for in accordance with the chemical views of the electric current and its action already advanced (913.), the water, instead of opposing a resistance to decom- Retardation produced by interposed Plates. 345 position equal to the full amount of the force of mutual attrac- tion between its oxygen and hydrogen, has that force coun- teracted in part, and therefore diminished by the attraction of the hydrogen at the cathode for the oxygen of the nitric acid which surrounds it, and with which it ultimately combines instead of being rendered in its free and independent state. 1022. When a little nitric acid was put into the exciting cells, then again the circumstances favouring the transmission of the current were strengthened, for the intensity of the cur- rent itself was increased by the addition (906.). When there- fore a little nitric acid was added to both the exciting and the retarding cells, the current of electricity passed with very con- siderable freedom. 1023. When dilute muriatic acid was used, it produced and transmitted a current more easily than pure dilute sul- phuric acid, but could not compete with nitric acid. As muriatic acid appears to decompose more freely than water (765.), and as the affinity of zinc for chlorine is very power- ful, it might be expected to produce a current more intense than that from the use of dilute sulphuric acid; and also to transmit it more freely by undergoing decomposition at a lower intensity (912.). 1024-. In relation to the effect of these interpositions, it is necessary to state that they do not appear to be at all de- pendent upon the size of the electrodes, or their distance from each other in the acid, except that when a current can pass^ changes in these facilitate or retard its passage. For on re- peating the experiment with one intervening and one pair of exciting plates (1011.), fig. 20, and in place of the interposed plate P using sometimes a mere wire, and sometimes very large plates (1008.), and also changing the terminal exciting plates Z and P, so that they were sometimes wires only and at others of great size, still the results were the same as those already obtained. 1025. In illustration of the effect of distance, an experi- ment like that described with two exciting pairs and one in- tervening plate (1012.), fig. 21, was arranged so that the di- stance between the plates in the third cell could be increased to six or eight inches, or diminished to the thickness of a piece of intervening bibulous paper. Still the result was the same in both cases, the effect being no greater, sensibly, when the plates were merely separated by the paper, than when a great way apart; so that the principal opposition to the cur- rent does not depend upon the quantity of intervening elec- trolytic conductor, but on the relation of its elements to the Third Series, Vol. 6. No. 35. May 1835. 2 Y S'l-G Dr. Faraday's Experimoital Researches in Electricity* intensity of the current^ or to the chemical nature of the elec- trodes and the surrounding fluids. 1026. When the acid was sulphuric acid, increasing its strength in any of the cells, caused no change in the effects ; it did not produce a more intense current in the exciting cells (908.), or cause the current produced to traverse the decom- posing cells more freely. But if to very weak sulphuric acid a few drops of nitric acid were added, then either one or other of those effects could be produced ; and, as might be expected in a case like this, where the exciting or conducting action bore a direct reference to the acid itself, increasing the strength of this (the nitric acid), also increased its powers. 1027. The nature of the interposed plate was now varied to show its relation to the phaenomena either of excitation or retardation, and amalgamated zinc was first substituted for platina. On employing one voltaic pair and one interposed zinc plate, fig. 28, there was as powerful a current, apparently, as if the interposed zinc plate was away. Hydrogen was evolved against P in cell ii, and against the side of the second zinc in cell i ; but no gas appeared against the side of the zinc in cell ii, nor against the zinc in cell i. 1028. On interposing two amalgamated zinc plates, fig. 29, instead of one, there was still a powerful current, but inter- ference had taken place. On using three intermediate zinc plates, fig. 30, there was still further retardation, though a good current of electricity passed. 1029. Considering the retardation as due to the inaction of the amalgamated zinc upon the dilute acid, in consequence of the slight though general effect of diminished chemical power produced by the mercury on the surface, and viewing this inaction as the circumstance which rendered it necessary that each plate should have its tendency to decompose water assisted slightly by the electric current, it was expected that plates of the metal in the unamalgamated state would pro- bably not require such assistance, and would offer no sensible impediment to the passing of the current. This expectation was fully realized in the use of two and three interposed unamalgamated plates. The electric current passed through them as freely as if there had been no such plates in the way. They offered no obstacle, because they could decompose water without the current ; and the latter had only to give di- rection to a part of the forces, which would have been active whether it had passed or not. 1030. Interposed plates of copper were then employed. These seemed at first to occasion no obstruction, but after a lletardation produced by interposed Plates. 347 few minutes the current almost entirely ceased. Tliis effect appears due to the surfaces taking up that peculiar condition (1040.) by which they tend to produce a reverse current; for when one or more of the plates were turned round, which could easily be effected with the couronne des tasses form of experiment, fig. 18, then the current was powerfully renewed for a few moments, and then again ceased. Plates of platina and copper, arranged as a voltaic pile with dilute sulphuric acid, could not form a voltaic trough competent to act for more than a few minutes, because of this peculiar counteract- ing effect. 1031. All these effects of retardation, exhibited by decom- position against surfaces for which the evolved elements have more or less affinity, or are altogether deficient in attraction, show generally, though beautifully, the chemical relations and source of the current, and also the balanced state of the affi- nities at the places of excitation and decomposition. In this way they add to the mass of evidence in favour of the identity of the two ; for they demonstrate, as it were, the antagonism of the chemical powers at the electromotive part with the che- mical powers at the interposed parts ; they show that the first are producing electric effects, and the second opposing them ; they bring the two into direct relation ; they prove that either can determine the other, thus making what appears to be cause and effect convertible, and thereby demonstrating that both chemical and electrical action are merely two exhibitions of one single agent or power (916. &c.). 1032. It is quite evident that as water and other electro- lytes can conduct electricity without suffering decomposition (986.), when the electricity is of sufficiently low intensity, it may not be asserted as absolutely true in all cases, that when- ever electricity passes through an electrolyte, it produces a definite effect of decomposition. But the quantity of electric city which can pass in a given time through an electrolyte without causing decomposition, is so small as to bear no com- parison to that required in a case of very moderate decompo- sition : and with electricity above the intensity required for decomposition, I have found no sensible departure as yet from the law of definite electrolytic action developed in the preced- ing series of these Researches (783. &c.). 1033. I cannot dismiss this division of the present paper without making a reference to the important experiments of M. Aug. De la Rive on the effects of interposed plates *. As I have had occasion to consider such plates merely as giving^ * Annates de Chimie [et de Physique^, iom. xxviii. p. 190; and Memoires de Geneve, 2 V2 348 Prof. Young oji the Stimmation of rise to new decompositions, and in that way only, causing ob- struction to the passage of the electric current, I was freed from the necessity of considering the peculiar effects described by that philosopher. I was the more willing to avoid for the present touching upon these, as I must at the same time have entered into the views of Sir Humphry Davy upon the same subject*, and also those of Marianinif and Ritter:f, which are connected with it. [To be concluded in the next number.] LVII. On the Summation of slowly converging and diverging Infinite Series. By J. R. Young, Professor of Mathematics in Belfast College, /COMMODIOUS methods for approximating to the sum ^-^ of a slowly converging infinite series are very valuable in many departments of physical science. Philosophical in- quiries of the highest interest and importance frequently ter- minate in series of this kind, which would be practically use- less, on account of the impossibility of the actual summa- tion, did we not possess the means of transforming them to others of such rapid convergency that the sum of a moderate number of the leading terms may in each case afford a near approximation to that of the entire series. Of all such me- thods of transformation that furnished by the well-known Differential Theorem is, perhaps, the most extensively appli- cable ; and it is, therefore, in one form or other, generally employed for this purpose. In the application, however, of this theorem, as well as in that of all other practical formulae intended to abridge numerical labour, there is room for the exercise of some ingenuity as to the most advantageous ar- rangement of the arithmetical process ; for if this arrangement be not such as to render the amount of calculation by the pro- posed formulae a minimum, it is plain that we do not derive from that formula all the advantage, as a facilitating principle, which it is capable of affording. In the present paper it is my wish, first to give a short and easy investigation of the differential theorem, and, by deducing it in a somewhat more complete form than that in which it usually appears, to show that it is capable of furnishing, not only a near approximation, but also very close superior and inferior limits, to the sum of a slowly converging or diverging ♦ Philosophical Transactions, 1826, p. 413. [or Phil. Mag. and Annals, N.S., vol. i. p. 193.— Edit.] t Annalex de Chimie [et de Physique], torn, xxxiii. pp. 117, 119> &c. X Journal de Physique, torn. Ivii. pp. 349, 350. slowly convergifig aiid diverging Irifinite Series. 349 series; and lastly, to exhibit its numerical application in a more commodious form than any in which I have yet seen it. Let a — bx-\-cx^—da^-\-^c, = S .*. —bx-^cx'^—dj!^-\-hc, = S—a S—a b+cx—dx'^ + ea^'^Sic. = x-hl .'. — 6— Aa?+ A'j;*^— AV + &C. = (S-a) .-. -^;a:-^Aa:^ + A'^'-AV + &c. = (a:+l)(S-a) = S^' .-. S = -^ +a ; that is, ^ bx Ax^ , A^a^ AV ^ = a- -^4-_f-/o-A^ + A^x^~AVH-&c.l^ x + \ x + l \ J Hence, treating the series within the brackets as we have treated the original, to which it is similar in form, we have 07 + 1 {x + lf (x + lf'^lx + lY {x + lf^^"^' Similarly, bx Ax^ __4^__^l£*_ A!j^__q, ^-"^ x-^l {x^-lf {x + \y {x + \Y^{x + lY ^°' bx Ax^ A'^JT' A«^«+^ S = a — ^+1 (x^-lY (x-\-\f , {J7+1)«+1 A n+1 ^n+2 These several expressions for S may be regarded as sq many differential theorems, but the last is that which corre- sponds most nearly to the form usually given : it is, however, more efficient, as it shows that if we stop at the term A "^"+^ (.r+l)"+i"' we get one limit to the sum S, and if we stop at the imme- diately following term we get another limit, in the contrary sense. These limits, as> 350 Prof. Young on the Summation we shall presently see, may be easily narrowed. By consi- dering die series to terminate at the former of the above terms, it will be the same as that investigated by the late Mr. Baron Maseres, in his Scriptores Logaritkmici, vol. iii. p. 219, and which the Baron considered to be different from that deduced by Simpson, from a formula still more general, in his Mathe- matical Dissertations, p. 62. The two forms are, however, mutually interchangeable, regard being paid to the signs of the differences. Suppose in the series S that a = 0 ; then, dividing both sides of (A.) by — .r, we shall have S = b — ex + dx^ — ex^ -{■ &c. = A^ A^^^ A" x^ n+l ^,n + l -&c (B.) which when x ■= \ becomes S = Z> — c + (/— e+&c. = 2 ^ 4 ^ 8 ^^^ + 2"+i ••• ^ ^ A" This series, supposing it to terminate at — ri, furnishes the method proposed by Dr. Hutton (Mathemat. Tracts, vol. i. p. 176). lii Dr.Hutton's process the value of S is approached by determining in succession the values of h b ^ A ^ , A _^ A^ . which is done by finding first the successive sums of a few of the leading terms in the proposed series, taking the arith- metical means between each pair of consecutive results, then the means between each pair of these means, and so on. But simple as this operation undoubtedly is, yet, when the num- bers consist of several places of figures, it cannot safely be performed mentally; so that Dr. Button's numerical examples, which exhibit only the results of these operations, do not fairly present the whole amount of numerical labour. Still his me- thod is, upon the whole, more easy and convenient than any which 1 have elsewhere seen, although, like all the other me- thods, it leaves us in doubt about the accuracy of the final decimal or two in the results determined by it, as indeed, every process of approximation must do which does not fur- nish limits both above and below the value sought. ofdawly converging and diverging Injimte Series, S5l In the series above marked (B.) it is plain that if we stop at the term involving A", we shall obtain an inferior limit to the Slim S, and if we take in the term immediately following we shall get a superior limit. Now, to narrow these limits, we must observe, that since A«+i= A"- A", a superior limit will be obtained by adding to the inferior limit the quantity Moreover, the inferior limit cannot differ from the entire sum by so much as whereas the superior limit differs from the truth by more than A"'^+^ (A"+^and, consequently, half the sum of the two limits will be a superior limit still nearer. We may conclude, therefore, that if we multiply the final term in the inferior limit by — , and add the product to that limit, we shall thus obtain a near superior limit. It is scarcely necessary to observe here, that in what has been hitherto said, the coefficients in the proposed series S are supposed continually to diminish, as also the several series of differences, which supposition is conformable to what usually occurs in practice when S is convergent. When the series is divergent, the formula (B.) or (A.) is still applicable, regard being paid to the signs of the differences. 1. As a first example, let there be proposed the slowly con- verging series which expresses the length of the quadrantal arc of a circle whose diameter is 1. It will be advisable to actually sum up a few of the leading terms, and to apply the formula (B.), or rather (C), to the remaining part. The work may be ar- ranged as follows : 352 Prof. Young on the Summation + 1 + •3 •2 •142857 •111111 •090909 '4-4012 = sum of first six terms. 10256 7844 6191 5013 2412 1653 1178 759 475 284 -H -076923 — -066667 + -058823 — -052632 + -047619 The numbers -076923, 10256, 2412, and 284 are the re- spective values of 6, A, A^ A^ and A'^in (C), and to deduce from these the value of S, it will be necessary merely to add half the last number 284 to the preceding, half the sum to the next, and so on, to the last, adding half the final sum to the number '744012 previously found. The remainder of the operation, therefore, is as follows : •076923 10256 •082767 11688 -041384 5844 -744012 2412 2864 1432 759 901 452 284 142 •785396 = inferior limit. 142 4 = •785400 = superior limit. -785398 = -^ very nearly. This value of -— we know from the small interval between 4 the limits cannot possibly differ from the truth by more than a unit in the final decimal. It is, in fact, true even in the last decimal. We have separated the two parts of the process in this example for the purpose of clearer illustration; but they may be combined as in the following. 2. To find the value of the converging series 3^ 3^.5" 3^ 5^ 1^ "T 7r3 Ti ^9 aq. ^9 "I ;T) ^j ,.j -^o — oCC, 1 2^ 2^4" 2^4^6' 2^4^ 6^8^ -which occurs in the expression for the time of vibration of a pendulum in a circular arc, of slowly converging and diverging Infinite Series, 353 + 1 - -25 + • 140625 - 97656 + 745768 - 60562 50889 43879 38565 34399 31045 54900 27450 •807175 •807175 = sum of first six terms. 7010 5314 4166 5354 8022 4011 1696 1148 812 2023 1012 548 336 654 327 212 106 ■834625 = inferior limit. 106 2* 3 = 834628 = superior limit. .-. 834626 = S very nearly. A value which cannot differ from the truth by more than a unit in the last decimal. It is, in fact, true in all its places, 3. Let it be required to find the value of the diverging series 1 2 3 4 „ + •5 -'666666 + •75 -•8 + •833333 -•857143 -•240476 + 875000 — 13889 — 888889 11111 + 9 09091 - 909091 07576 + 916667 14499 867251 7749 -2778 2020 1515 3220 1610 ■758 505 884 442 253 126 433625 -240476 193149 = superior limit. 126 •193145 = inferior limit. Hence very nearly, which is true in the last decimal. Third Series, Vol.6. No. 35. May 1835. 193147 = S 2Z 354 Dr. C. Henry's Experiments on the Action of Metals 4. As a last example let the series 1 — 2 + 4 — 8 4- &c. be proposed. Then, comparing with the formula (B.)j we have j: = 2 and b^ c, &c. each = 1, . S= -A_= 1 x + l 3" In a similar way may the sum of 1—4 + 9—16 be readily found. March 9, 1835. J. R. YoUNG. [To be continued.] LVIII. Experiments on the Action of Metals in determining Gaseous Combination, By William Charles Henry, M.D., KR.S* •T^HE property, first discovered by Dobereinerf in spongy -*- piatina of inducing gaseous union, has been recently shown by Dr. Faraday^ to exist also in compact plates of that metal, as well as in plates of palladium and of gold, and hence to be independent of fineness of division or porosity of structure. This important result, while it demonstrated the inadequacy of all theories of the action of piatina that had been before proposed, suggested to Dr. Faraday the idea, that gaseous combination, thus induced, may be due partly to the statical relations subsisting between elastic fluids and the solid surfaces by which they are bounded, and partly to an attrac- tive force, exerted at insensible distances, and probably be- longing to all bodies. By the joint influence of these two con- ditions, the gases, he imagines, are so far condensed on the metallic surface " as to be brought within the action of their mutual affinities at the existing temperature." This ingenious theory, though mainly resting on the fact that perfect purity from foreign matter is the only condition in the metallic sur- face essential to its activity, is further supported by an exten- sive induction of analogous actions. Receiving the theory of Dr. Faraday, in so far as it has been developed by him, as correctly representing the nature of these phaenomena, it still remains to assign a cause for the * Read before the Literary and Philosophical Society of Manchester; and communicated by the Author. •j- [An account of Prof. Dobereiner's experiments, and of those of other chemists, on the same subject, will be found in Phil. Mag. (First Series), vol. Ixii. p. 282 — 292 : see also vol. Ixiii. p. 71, and vol. Ixiv. p. 3. — Edit.] J [An abstract of Mr. Faraday's Sixth Series of Experimental Researches in Electricity, containing his observations on this subject, was given in Lend, and Edinb. Phil. Mag., vol. iv. p. 291.— Edit.] /;/ determining Gaseous Combination, 355 marked preeminence of platina, and of a few metals closely allied to it in chemical properties, over all other metals and solid bodies that have been the subjects of experiment. Thus platina has been shown to induce gaseous union at so low a temperature as —4° Fahrenheit*, and palladium and gold in the form of plates, and rhodium and iridium in the state of powder, at atmospheric temperatures. All other metals and solids are entirely inert at the temperature of the atmosphere, and, with the exception of silver and osmium, require, in order to effectuate gaseous union, to be heated nearly to the boiling point of mercury. Now the statical condition of the film of gaseous niatter contiguous to the metallic superficies (one of the causes assigned by Dr. Faraday of greater density in that portion of the gaseous mixture) being quite independent of the nature of the bounding solid, must cause an equal degree of condensation upon all the metals, and, indeed, upon all con- tinuous surfaces. The attractive force (the other postulate in Dr. Faraday's theory) may be supposed to be of variable amount in different solid bodies. But no experimental proof has yet been given that platina possesses a stronger attraction than the other metals for gaseous fluids; on the contrary, the experiments of Magnus f have shown that iron, nickel, and cobalt absorb or condense the different gases to a large amount. The following experiments (in several of which I was in- debted for valuable assistance to my friend Mr. Joseph Ran- some,) were designed to investigate the cause of the inferiority of the other metals to platina in determining the union of hy- drogen and oxygen. Since these actions, whatever be their essential character, manifestly reside on surfaces, it seemed probable that by employing the metals in that state in which they present the largest amount of superficial extension, and by thus augmenting the energy of the operating forces, their true nature might be unfolded. Mechanical processes seemed inadequate to ensure an absolutely untarnished surface ; and the chemical agents, employed with success by Dr. Faraday, for cleansing the surface of platina, were obviously inapplica- ble to the oxidizable metals. The most promising mode of obtaining this class of metals in the requisite state of purity and mechanical division appeared to consist in precipitating them from their salts in the condition of oxides, and in re- ducing those oxides by heating them in hydrogen gas. Several preliminary experiments showed that bright copper turnings, zinc-foil, iron turnings, box-wood charcoal recently * Delarive and Marcet, Ann. de Cliim. et de Phys., torn, xxxix. p. 328. t Ann. de Chinu et de Phys.y torn. xxx. p. 103. 2 Z2 S56 Dr. C. Henry's Experiments on the Action of Metals ignited and cooled under mercury, and pounded glass washed in hot alkali and acid and then repeatedly in distilled water, when introduced into curved tubes containing oxygen and hydrogen in the proportions constituting water, did not induce the silent union of the gases, until the tubes were heated to near the boiling-point of mercury. All these substances acted nearly at the same temperature. § I. Copper, 1. Oxide of copper, obtained by calcination of the nitrate, was exposed in a green glass tube to a current of hydrogen, issuing from dilute sulphuric acid and zinc. The temperature was gradually raised by a spirit-lamp to a low red heat, when the process of reduction commenced, and the bright incan- descence, described by Berzelius, was observed to spread along the powder, in the line of reduction, even after the lamp had been withdrawn. The metallic copper thus obtained was light and spongy, and underwent no change in the atmo- sphere at ordinary temperatures. 2. A portion of this copper, exposed to the air in an open capsule, was heated on a sand-bath to upwards of 500° Fahrenheit, and a stream of hydrogen made to flow constantly over its surface. The gas was not inflamed, but the metal itself became rapidly tarnished, and was finally reconverted into black oxide. Precisely the same change was effected by simply heating the metal without the presence of hydrogen. 3. Oxide of copper, thrown down from the sulphate by caustic potassa, and sufficiently washed with distilled water, was reduced in the same manner. A jet of hydrogen was di- rected upon the pure and porous copper so obtained, which was then slowly heated on a platina dish by a spirit-lamp. As in the last experiment, it speedily began to lose the metallic aspect, and was reconverted into black oxide. The heat was increased to near redness, when the powder suddenly be- came incandescent, and though the lamp was withdrawn, con- tinued to glow brightly as long as the current of hydrogen was supplied. In appearance the incandescence was identi- cal with that of powdered platina or rhodium under like cir- cumstances. Copper, then, in a state of fine mechanical division, does not, like platina, dii'ectly induce the union of hydrogen with oxy- gen at any temperature. At all temperatures below that at which its oxide is reducible, the affinity of copper for oxygen surpasses the affinity of hydrogen for oxygen. Hence when heated in the open air, either with or without the presence of hydrogen gas, the copper absorbs oxygen, and is finally con- verted into the state of black oxide, hydrogen, it' present, ill determining Gaseous Combination. 357 'fc> escaping unburned. These actions are exhibited in the first experiment. But if the heat be raised to the degree at which oxide of copper is reducible by hydrogen gas, the newly- formed oxide yields its oxygen to hydrogen in the open air just as in a closed tube, and becomes, as in the latter case, incandescent. The continuance of the glow, after removing the lamp, is due to a succession of alternate reductions and reoxidations ; for the metal, at the moment of reduction, be- ing at the temperature at which it can unite with the oxygen of the air, is reconverted into oxide, which is again reduced by the hydrogen ; the necessary temperature of the mass be- ing sustained by other contiguous portions in the state of in- candescence. It is therefore not metallic copper, but oxide of copper, which induces the combustion of the hydrogen, and the silent formation of water, hr further proof of this mode of action, it may be added, that oxide of copper from the ni- trate, exposed on a platina dish to a current of hydrogen with free access of air, and gradually heated to below visible red- ness, became incandescent, and continued to glow as long as a stream of hydrogen was directed upon it. % II. Lead. Hydrate of lead thrown down by potassa from the acetate, was heated in a glass tube, in contact with hydrogen gas, until it was converted into a dark grey powder. This powder was heated in the open air, and a stream of hydrogen was di- rected upon its surface. It was notwithstanding converted into protoxide, sometimes with, sometimes without, faint incan- descence. On increasing the heat, the surface of the oxide upon which the hydrogen impinged was again reduced, while the remoter portions became pink and passed slowly into a higher degree of oxidation. Since, then, recently reduced copper and lead, though rank- ing among metals endowed with feeble affinities for oxygen, exert a stronger affinity than hydrogen gas for that element, it might be anticipated that the more oxidizable metals, and especially such as are capable of decomposing water, would a fortiori fail to induce direct gaseous union. % III. Cobalt. 1. Oxalate of cobalt obtained from zaffre (by Dr. Thom- son's process) was heated in a glass retort, witliout access of air, till carbonic acid gas ceased to be evolved, and the me- tallic cobalt was left in the form of a black powder. The co- balt obtained by this process was not pyrophoric, nor did it inflame a jet of hydrogen directed upon it at the existing tem- perature. When heated to considerably below visible red- 358 Dr. C. Henry's Experiments on the Action of Metals ness, the powder became incandescent and was converted into an oxide. A stream of hydrogen directed upon it in this state supported the incandescence for an unlimited period, without the aid of external heat. 2. Protoxide of cobalt was reduced in a tube by hydrogen at a low red heat, without exhibiting incandescence. During reduction the colour of the powder changed from black to ash-grey. Small portions of the reduced metal, when scat- tered on paper, ignited spontaneously, as in the experiment of Magnus, and inflamed the paper. The rest of the powder was quickly transferred from the reducing tube to a platina dish, upon which a current of hydrogen had been previously directed. The metal instantly became incandescent, and con- tinued to glow as long as hydrogen gas issued in sufficient abundance. No external heat was employed. The substance left at the conclusion of the experiment was in all respects analogous to the original protoxide, except that its colour was of a deeper black. Cobalt, then, like the less oxidizable metals, is destitute of the property of inducing the union of hydrogen with free oxy- gen. Its action is the same as that of copper, except that the incandescence takes place during the stage of oxidation, not during that of reduction. § IV. Nickel, 1. Nitrate of nickel was heated to redness in a porcelain crucible till nitrous fumes ceased to be disengaged. The ash- gray protoxide thus obtained was reduced in a glass tube by hydrogen. During reduction, the colour changed to a brownish black, but the powder did not become incandescent. The metallic nickel was not pyrophoric, nor did it act upon a jet of hydrogen at the temperature of the atmosphere. When slowly heated on a platina tray, the hydrogen con- tinuing to flow over its surface, it became incandescent, and was maintained in that state till the current of hydrogen ceased. The portion of powder contiguous to the orifice from which the hydrogen issued, was distinguished from the remoter parts by a marked difference of colour. That upon which the hydrogen was acting, was of lighter colour than the original protoxide. The powder most distant from the jet was of darker gray, and when heated, without contact with hydrogen, glowed tor a moment, and assumed the same tint as the part that had been kept incandescent. 2. A second portion of the metallic nickel was simply heated out of contact with hydrogen gas : it became incandescent, but speedily ceased to glow, being reconverted into oxide. 3. Finally, protoxide of nickel was heated in an open dish, in determinins: Gaseous Combination, 359 'to upon which a stream of hydrogen was flowing. It became incandescent considerably below visible redness, and con- tinued so as long as hydrogen was supplied. The action of nickel differs, then, in no respect from that of cobalt, but consists in a similar succession of oxidations and reductions. It is therefore entirely distinct from that of pla- tina and its congenera* ; yet nickel has been placed by Dobe- reiner, MM. Dulong and Thenard, and Mitscherlich f , all of whom observed its activity in the form of sponge, in the same category with platina and the noble metals. § V. Iron, 1. The yellow oxalate of iron was heated in a closed retort until carbonic acid was no longer liberated. The reduced metal was pyrophoric when poured through the air. A por- tion, carefully transferred from the retort to a platina dish, on which a current of hydrogen was flowing, became incan- descent without foreign heat ; and a circular ring of powder nearest the aperture from which the gas issued, continued to glow as long as hydrogen was produced. The oxide imme- diately contiguous to this ignited circle was black, but the remoter parts had passed into the state of red oxide and un- derwent no further change. The incandescence continued for many minutes, and at length became so vivid as to kindle the jet of hydrogen J. After the experiment had terminated and the product been allowed to cool, it appeared that the metal was entirely con- verted into the state of oxide, and chiefly of red oxide. This oxide was heated on a platina dish, and a stream of hydrogen directed upon it. About the temperature of reduction it became incandescent at the points of its surface where the hydrogen impinged, and after the lapse of a few minutes in- flamed the hydrogen. It appears, then, that iron, when recently reduced and in a pulverulent state, does not induce the direct combination of hydrogen with oxygen. Like the other oxidizable metals be- fore enumerated, it causes the silent formation of water, only * " celle de faciliter par leur contact la combinaison des fluides elastiques sans s*unir a aucun de ces fluides ou de leurs composes." — Thenard, torn. ii. p. 19. 6"™^ Edit. t Lehrbuch der Chemie, b. i. p. 226. X This experiment, as well as the second on cobalt, are liable to objec- tion from the pyrophoric state of the metals, and are only introduced as completing the series. Stromeyer has also called in question the perfect reducibiliiy of oxide of iron by hydrogen, and is of opinion that the pyro- phoric substance is the protoxide, and not the pure metal. 360 Dr. C. Henry's Experiments on the Action of Metals at the temperature of reduction. It then alternately absorbs the oxygen of the air and yields it to the hydrogen, in the same mode as a given portion of nitrous gas has been supposed to act in repeatedly carrying the atmospheric oxygen to sul- phurous acid in the process of making oil of vitriol. § VI. Silver, As a contrast to the results of the foregoing experiments, oxide of silver, obtained from the nitrate by caustic potassa, was heated on a platina dish, in the open airi and a current of hydrogen made to flov^^ upon it. The oxide wvls instantly reduced, and the pure metal underwent no further change, but, when strongly heated, inflamed a jet of hydrogen, without itself becoming incandescent. The property of inducing the union of hydrogen with oxy- gen, at common temperatures, had been ascribed by former inquirers to nickel as well as to the noble metals. It must now be restricted to the section of metals which are characterized " as incapable of absorbing oxygen or decomposing water at any temperature, and whose oxides are reducible below a red heat." The foregoing experiments further demonstrate that the oxidizable metals, when so minutely divided as to be in great measure freed from the control of cohesive attraction, and at liberty to obey their natural affinities, do not at any temperature determine the direct union of hydrogen with free oxygen; their own more energetic affinity for oxygen pre- dominating over the weaker affinity of hydrogen for oxygen, and inducing the oxidation of metal in preference to the for- mation of water. When raised to a low red heat, in contact with hydrogen, and with access of air, the oxides of these metals have been further shown to cause the combustion of hydrogen, by yielding their oxygen to that element, and in- stantly recombining with fresh atmospheric oxygen. The continued incandescence thus exhibited, though apparently identical with that of platina, has been traced to a series of alternate reductions and reoxidations. When in a state of more compact aggregation, these metals, it is true, effectuate gaseous combination, but only at a tem- perature approaching that of boiling mercury*. In this state * It may be doubted whether, even in the compact state, the oxidizable metals permit the union of hydrogen with oxygen, until their own surfaces have combined with oxygen. For the metallic foil and turnings, which were pure and bright when introduced into the mixed gases, were found to be tarnished and covered with a film of oxide when withdrawn, after having induced gaseous union. in determining: Gaseous Combination^ 361 "to the force of cohesion restrains the affinity of the metal for oxygen, and thus enables the hydrogen to exert, at a tempe- rature of about 650° Fahrenheit, that stronger attraction for oxygen which, when directed upon a Jinely divided metal or oxide, it does not manifest below an incipient red heat. Finally, it appears probable that the particles of oxygen and hydrogen are brought within their combining distances on the surface of iron or copper as well as on that of platina, but that on the oxidizable metals their combination is pre- vented by the stronger affinity of the contiguous atoms of metal for oxygen. Another argument, in favour of the view which has been taken, is the inactivity of platina itself, noticed by Dr. Faraday, when introduced into mixtures of hydrogen and chlorine, gases which are so much more readily combinable by other means tlian hydrogen and oxygen. This inactivity is most probably due to an interfering affinity of platina for chlorine, — an electro-negative which manifests far more energetic affi- nities for the metals than oxygen exerts, and is indeed, the only solvent of gold and platina, when presented to them, in its nascent state, in aqua regia. The power which certain gases exercise of suspending or wholly preventing the action of platina on mixtures of hydro- gen and oxygen, was several years ago ascribed to the similar interference of an opposing affinity. (Dr. Henry on the Action of Spongy Platina on Gaseous Mixtures, in the Philosophical Transactions for 18ti4?*.) In that essay it was shown that the . only gases possessing this singular property are such as are capable, under the influence of platina, of combining with oxygen, either at atmospheric or at moderately elevated tem- peratures. Thus, carbonic oxide — which, when added in the proportion of half a volume to one volume of a mixture of hydrogen and oxygen, prevented the action of the sponge, — is known to combine slowly with oxygen in presence of the sponge at ordinary temperatures, and rapidly at a heat be- tween 300° and 340° Fahrenheit. It is there, also, proved that the affinity of carbonic oxide for oxygen greatly surpasses that of hydrogen for oxygen within a considerable range of tem- perature. " When carbonic oxide and hydrogen gases in equal volumes, mixed with oxygen sufficient to saturate only one of them,were heated in contact with the sponge to 340°, four fifths of the oxygen united with the carbonic oxide, and only one fifth with the hydrogen." A similar relation between the • [Dr. Henry's paper will be found also in Phil. Mag. (First Series), vol. Ixv. p. 269.— Edit.] Third Series. Vol. 6. No. 35. Mai/ 1835. 3 A 362 Dr. C. Henry's Experiments on the Action of MetaJs affinities of carbonic oxide and hydrogen for oxygen was ob- served in their slow combination at atmospheric temperatures. " The oxygen which had united with the carbonic oxide was to that which had combined with the hydrogen as about 5 to 1 in volume." From the foregoing facts it may be inferred that when either carbonic oxide or hydrogen gas is condensed with oxy- gen on the surface of platina, it is brought within the range of its combining affinity, and unites with oxygen, the latter rapidly, the former with such extreme slowness as to give evi- dence of the production of carbonic acid only after the lapse of a day or two. When the two gases are simultaneously con- densed with oxygen sufficient to saturate only one of them, the stronger affinity of carbonic oxide for oxygen prevails over the weaker affinity of hydrogen for oxygen, and induces the formation of carbonic acid, but so tardily as to exhibit no immediate action, and hence to give occasion to the phae- nomena of interference. The retarding influence of foreign gases may, then, like the non-action of the oxidizable metals, be traced to the operation of a countervailing affinity. The insufficiency of most of the hypotheses previously framed to explain this class of phaenomena has been fully ex- posed by Dr. Faraday. There is one, however, which de- serves to be noticed, since, though adopted by some of the most eminent German chemists, it appears to have escaped his ob- servation. Proposed by Dobereiner in Schweigger's Journal, it seems to have reached the Annates de Chimie only through a memoir of Liebig*. Platina in the form of powder is as- serted by Dobereiner to absorb many volumes of the unmingled gases, and especially of pure hydrogen. Thus, 100 grains absorbed 20 cubic inches of hydrogen, or in volume 1 cubic inch of powder absorbed 745 cubic inches of the gas. A small part of this (5 cubic inches) is supposed to have been employed in the formation of water, and the remaining 15 cubic inches to have been simply condensed by the powder, by an action resembling, but greatly exceeding in amount, that of charcoal. The heat evolved by this enormous condensa- tion is calculated to be fully adequate to render the metal in- • torn. xlii. p. 316. [We cannot at present refer to Schweigger, but the passage in the Annales]u%t cited, relates merely to the black precipi- tate obtained by Mr. E. Davy by heating sulphate of oxide of platinum with alcohol, and not to platinum powder. This, in conjunction with the statement mentioned in our note on the succeeding page, seems to indicate the existence of some error in the history of the subject as stated above. Perhaps Dr. C. Henry will have the goodness to reconcile the apparent contradiction in our next Number. — Euix.] in determining Gaseous Combination, 363 candescent, and to inflame the gas, if oxygen be present. Mitscherlich also regards the action of charcoal, in causing the rapid union of sulphuretted hydrogen and oxygen, as identi- cal in character with that of platina on other gaseous mix- tures*. Other experimenters have stated, on the contrary, that platina exerts no appreciable action on pure hydrogen or pure oxygen, and have sought the theory of its operation in the phaenomena of its contact with those gases in a state of mix- ture f. It appeared, therefore, important to contrast by fresh observations the action of platina with that of charcoal upon the simple gases. In these experiments I employed box- wood charcoal, which was heated to redness and cooled under mercury before ad- mission into the gases. The results constituted a series of numbers very nearly accordant with those of Saussure, with the single exception of sulphuretted hydrogen, which was ab- sorbed in larger proportion than is stated by that experi- menter. One volume of charcoal, I found, absorbed eighty- one volumes of sulphuretted hydrogen. The absorption was always effected with far greater rapidity during the first mo- ments of contact with all the gases than afterwards. Platina, in the form of sponge and of clay balls, was simi- larly introduced into tubes containing the separate gases over mercury. No immediate diminution of volume could ever be detected ; and in most trials, the space occupied by the gas was increased by a quantity equivalent to the volume of the platina sponge or ball. In some cases, when the sponge was left for a day or two in contact with the gas, there was an appreciable, though very slight absorption. Thus, a small piece of sponge passed into 5 cubic inches of hydrogen did not by its own bulk augment the volume of the gas, and after the lapse of two days had absorbed about ^ cubic inch. In not one of the many experiments in which platina was introduced into pure oxygen gas, and allowed to remain for several days, was there any appreciable absorption. Even ammoniacal, muriatic acid and sulphuretted hydrogen gases, which are so largely and rapidly condensed by charcoal, underwent no immediate change of volume from exposure to spongy platina, * Lehrbuch der Chemie, b. i. p. 226 and 394. t Marcet and Delarive, Ann. de Ckim. et de Phys., torn, xxxix.; and Dr. Faraday (5H7). [It is remarkable that this statement had been originally made also by Dobereiner, as appears from a paper by Dr. Schweigger, in the Journal bearing his name, of which a translation was given in Phil. Mag., vol. Ixiv. p. 3. Schweigger quotes Dobereiner as saying that " the hydrogen is neither absorbed nor condensed by the metallic platinum dust, and in the recital of his experiments, that " No condensation of hydrogen occurred when I placed it in contact with platinum dust," and certain other substances which he mentions. — Edit.] 3 A 2 364 Dr. C. Henry's Experiments on the Action of Metals and were but slightly affected by prolonged contact with it. Since obtaining these results, 1 have observed that Thenard had previously given the same testimony*. The almost total absence of the power of absorbing gaseous matter in spongy platina, indicated by these experiments, is irreconcileable with the properties attributed to the black powder of Liebig, which is regarded by him as nothing more than pure metallic platina in a state of extreme subdivision. But the following experiments render it probable that, if not a suboxide of platina, the powder of Liebig is either a mixture of suboxide and metal, or at least retains much oxy- gen in the state of adhesion, and that the absorption of hy- drogen is mainly due to its conversion into water. Five grains of the powder, prepared according to the pro- cess described by Liebig, were compressed into the end of a glass tube, and protected, by a cork removeable at plea- sure, from the action of mercury, with which it rapidly amal- gamates. The tube was then filled with mercury and in- verted. Hydrogen in measured quantity was admitted. On withdrawing the cork and allowing contact of the gas and powder, there was a rapid absorption of the gas, with evident deposition of moisture. When the powder had ceased to act, it was found that '49 cubic inch of hydrogen had disappeared. Supposing this diminution to be entirely due to the formation of water, five grains of the powder must have contained '245 cubic inch of oxygen. To the same weight of black powder '72 cubic inch of car- bonic oxide was admitted. There was a diminution to '61, which, when washed with potassa, left '19. Hence *42 cubic inch of carbonic oxide had been converted into carbonic acid, for which '21 cubic inch of oxygen are required, a number according as nearly as can be expected with that given by the former experiment +. But if we even admit the powder of Liebig to be metallic platina in a finely divided state, this admission will not ex- plain the combining powers of laminated or spongy platina, which induces gaseous union, but does not absorb any ap- preciable volume of the separate gases. The theory of Dr. Faraday, so far at least as respects the two leading principles, * Traite de Chimie, torn. ii. p. 633. (G*"^ edit.) t In the few trials I have hitherto made with the powder of Liebig, its combining powers were in no degree interfered with by the presence of foreign gases. When introduced into an explosive mixture of hydrogen arrd oxygen, to which an equal volume of either carbonic oxide, olefiant gas, or even sulphuretted hydrogen had been added, the powder instantly glowed, and caused rapid combustion of the gaseous mixture; and when admitted into a mixture of carbonic oxide and oxygen, it occasioned instant combination with incandescence of the powder. in determining Gaseous Combination. S^5 upon which it rests, constitutes the most satisfactory explana- tion hitherto proposed of this class of actions. As regards the statical relations subsisting between gases and their bound- ing solids, it is perfectly accordant with the analytical deduc- tions of Laplace ^ ; and as respects an attractive force in so- lids, inducing gaseous condensation on their surface, many analogous facts assembled by Mitscherlichf may be added to the numerous illustrations supplied by Dr. Faraday himself. There is, however, one element of Dr. Faraday's reasoning, the validity of which appears to me questionable. In considering the mutual relations of mixed gases, he has assented to the doctrine of Dr. Dalton in the form in which it was first pro- posed, viz. " that gaseous molecules are only self-repulsive, or that the particles of one gas are indifferent to those of another gas." But this doctrine, soon after its announcement in the " Manchester Memoirs," was strongly controverted ; and among the objections raised against it, some were regarded by Dr. Dalton himself as sufficiently cogent to induce him, when treating the same topic in his " New System," to admit " that the phgenomena of mixed gases may be accounted for without the postulatum that their particles are mutually in- elasticX" Without reiterating arguments long ago ably urged §, it may be contended, that if heat be the sole cause of repul- sion, as is implied in Laplace's theory of elastic fluidity, it is impossible to admit that the atmosphere of heat surrounding the atoms of any gas A, and constituting those atoms mu- tually repulsive, can be indifferent to portions of the same heat associated with the atoms of another gas B. Laplace, therefore, in applying the analytical calculus to the condi-! tion of mixed gases, and of gases mixed with vapours, re- jects the supposed absence of repulsion between the mole- cules of different gases as theoretically improbable, and as in- consistent with known phaenomena ||. Finally, the admission of repulsive forces between unlike, as well as like, gaseous atoms, seems essential to the consistency of Dr. Faraday's reasoning (in section 630). For " the deficiency of elastic power" is there stated to influence union partly " by abstract- ing a part of that power (upon which depends their elasti- city) which elsewhere in the mass of gases is opposing their * La densite du gaz contenu dans iin vase est partout la meme, excepte dans les points tres voisins des parois a una distance egale on plus petite que le rayon de la sphere d'activite sensible des forces attractives et re- \mh\\' ea.— Mec. CeL, liv. xii, § 1. torn. v. p. 93. See also p. 105. t Lchrbuch der C/ieniie, b. i. p. 397- % « New System," pp. 189 and 162. § Ibid. p. 150-193. II " Cette hypothese est bien pen naturelle, elle est d'ailleurs contraire a plusieurs pheiiom^nes." — Mec. CeL, torn. v. p. 109 and 110. liv. xii. § 5. 366 Prof. Forbes on the Refraction and Polarization of Heat, combination." Unless the particles of oxygen were elastic or repulsive as respects the contiguous particles of hydrogen, elasticity could not be a force opposed to affinity, and the di- minution of elasticity or repulsion by the action of the plate, could not determine the union of oxygen with hydrogen *. Manchester, April 7, 1835. LIX. On the Refraction and Polarization of Heat, By James D. Forbes, Esq., F.R.SS. L. <^jE., Professor of Na- tural Philosophy/ in the University of Edinburgh, [Continued from p. 291, and concluded.] 66. T^HE table generally points to a coincidence, and that as -■• close as by the nature of the experiments we should perhaps be warranted in expecting. If there be any excess in the second column of results (which the observations with incan- descent platinum might lead us to suspect), it is more than probable that it arises from some imperfection in the appara- tus employed, such as the incomplete parallelism or perpen- dicularity of the mica plates employed to polarize, a circum- stance which was not minutely attended to. 67. The result, however, is highly satisfactory, as indica- ting the almost exactly complementary nature of the ordinary and extraordinary pencils, as in light. 68. The somewhat complicated conditions of the variable intensities of the ordinary and extraordinary images (which it is to be recollected correspond to the Parallel and Perpendi- cular positions of the analysing plate) in the case of light, are easiest kept in mind by Fresnel's formulae. 02= F^l 1 _ giii^ 2 i sin^ TT (^'"- ^) Y E2=F24^sin2 2/sin2 7r ^^""-A^ where 0^ E^ and F-, have the same signification as in (64), and / represents the angle between the plane of polarization and the principal plane of the crystal : o — ^ is the difference * In proof that the repulsion existinjr between unlike gaseous molecules is a force opposed to chemical union, it is worthy of remark, that of such gases as combine spontaneously, when simply mingled, one or both are generally found among that class which have been reduced to a liquid form, and in which the repulsive force between the constituent molecules is therefore least energetic. 2 ( 2 X I T t This corresponds to the formula ^sin^ 2 (5 1 1 — cos —^ | of Airy*s Tract on the Undulatonj Theory, Art. 172. Both are only restricted expressions of more general theorems. Prof. Forbes on the Refraction and Polarization of Heat. 367 of the retardations of the ordinary and extraordinary rays within the crystal, and X the length of an undulation. The sum of the two is always = F^. 69. Now the quantity o — e may always be known by re- ferring to the retardation, which produces the corresponding tint in Newton's rings, and which is equal to twice the distance between the plates in that experiment. For example, with the thin mica film mentioned in (56\ which polarized light circularly, the tint produced (between crossed polarizing and analysing plates) corresponded (by Newton's table) to an in- terval of about five millionths of an inch between the surfaces of glass, or to a retardation, [o— e\ of '00001 inch. The film, marked No. 2, which gave plum-red of the first order (65), gives a retardation of -00002. The film No. 1 {Q5), gives •00004. inch. From these data, then, having the value of E^ (68), it is clear that we may calculate the value of A, or the length of an undulation of heat*. 70. In our present case we have always made i = 45° ; whence E« = F^ sin ^^ (^^ ' ^"^ ^^ ^^"^^^ ^' = F^-E^. But in an experiment we must not use the direct indication of the multiplier, when the polarizing and analysing planes are parallel, for the total quantity or F^ ; for a large proportion of the heat is not completely polarized, and in order to compare the values of E"^ and F^, we must determine the value of each directly, that is, not only how much is depolarized, but how much is polarized by the mica plates. This 1 did by ascer- taining alternately with the quantities of depolarization, the total intensity of the polarized part of the heat, which reached the pile. This was effected by rendering the polarizing and analysing plates parallel and perpendicular to one another ; whilst the principal section of the interposed mica remained parallel to one or other, so as to exercise no depolarizing influence. 71. To illustrate this mode of investigation, I shall give as an example the very last series of experiments made on this subject, which, whilst it points out the mode of operating, will exhibit the constancy and considerable magnitude of these effects, amidst the complicated changes of condition to which the heat is subjected. The columns marked " corrected," have a small correction applied for the gradual alteration in the quantity of heat reaching the pile, which corrections are * Of course this is only true on the supposition that rays of heat and light are equally retarded. This is not demonstrated, but it is probable that they are nearly so, since that part of the heat which accompanies the spectrum is so, and the dispersion in the case of double refraction is incon- siderable. 368 Prof. Forbes on the Refraction and Polarization of Heat. interpolated from the successive observations marked (I), (2), (S), &c. which are made under similar circumstances. 1835. Jan. \Q,— Source of Heat, Incandescent Platinum. Po- larizing Mica Plates E and F. Film of Mica interposed. No. I. Position of Mica plates. [Eat 0°] F at 90° Fat 0« Fat 90° Fat 0<> F at 90° Fat Oo Fat 90° Fat 0° F at 90° Fat 0° Fat90o Fat 0° Principal Sec- tion of inter, posed Mica, at (45° (1) \45 / 45 (2) \45 / 45 (3) ^2 \45 / 45 (4) (^ \45 /45 (5) 145 1 45 (6) (^ 145 Multiplier. 140-8 2} 4} 4} ^i 3f 8} ^} ?} 8} «} 5} Total Po- larization. 6' •0 4 •0 4 •8 4 •5 4 •9 5 •0 Depolari- zation. Total Po.|Depolari- larization zation corrected , corrected -j_ 20-8^ + 2 '2' 6-0 4 '2 4-9 4-5 5 0 5'1 2°75 2 1 2-65 2-2 2-2 Mean, Ratio. 100 : 46 100 : 50 100:54 100 : 49 100 : 44 100 : 43 100 : 48 When the analysing plate F is said to be at 0°, it is pa- rallel to the plate E. When the principal section of the in- terposed film is at 0°, it is parallel to the plane of incidence at the plate E ; at 45° it is inclined 45° to that plane. The signs + and — in the column of " depolarization," indicate whether the effect of the interposed film was to increase or di- minish the heat transmitted. 72. The physical meaning of the expression for the inten- sity of the depolarized light, E^ = F^ sin^ tt (— "^) will be found to be this. When the thickness of the interposed film is such as to give a retardation of 0, X, or any whole multiple of A, E is equal to nothing, or no light is depolarized, and between those values the amount of E^, or the intensity of the depolarized light, will gradually increase from the values 0, Prof. Forbes on the Refraction and Polarization of Heat. 369 A, 2 a, &c. to the values — , — , — , &c. and again diminish A £t Zi in the same manner to the next limit. When the retardation is — -, '— , —, &c., half the light exactly is depolarized ; it is T? Tr 'x then circularly polarized ; in other cases, it is plane or ellip- tically polarized. 73. Similar effects might be expected to occur in the case of heat. But we must recollect that it is even more difficult to obtain homogeneous heat^ than homogeneous lights and that we shall have portions of heat differently depolarized by the same plate, (in consequence of the different character of re- frangibility, indicating a different length of undulation,) exactly as when we operate upon white light. We know that heat of various degrees of refrangibility constitutes the solar heat, and probably all other kinds. Hence, no one plate can com- pletely depolarize all these varieties. As far as my experi- ments go, made similarly to that of (71), heat unaccompanied by light is generally less depolarized by a plate of given thick- ness than heat vividly luminous. In the case of contrasting heat from an Argand lamp with that from incandescent pla- tinum, and heat quite dark, this is strikingly marked, though not so decisively in comparing the two last kinds. If the in- accuracy be not in the experiments, it may very probably arise from the want of homogeneity in the heat just alluded to. The want of any apparent depolarizing power for dark heat in the thin mica film mentioned in [5Q) is now easily explained. Its thickness was such as to polarize (nearly) circularly, the mean luminous rays. Its retardation, or o — e was then = — - for these rays. But we know from Melloni's experiments, that the heating rays are less refrangible than the luminous rays (I mean in heat from terrestrial sources, as well as that of the solar rays), and that generally in proportion to this ob- scurity. Therefore, on the undulatory hypothesis, their waves are longer. Hence a retardation of — for light, would be a retardation of less than — , if A be the length of a wave of heat from an Argand lamp ; it would be still less for heat from in- candescent platinum, and least of all for dark heat; hence, as the retardation is a smaller fraction of A or approaches zero, the depolarization or the value of E^ approaches zero. This perfectly coincides with the experiment of (56). 74<. Without attaching much weight to the numerical accu- Third Sei'ies. Vol. 6. No. 35. Mai/ 1835. 3 B 370 Prof. Forbes on the Refraction and Polarization of Heat, I'acy of the following results, it is worth quoting them as con- firming the general fact, that obscure heat has longer undu- lations than luminous heat. The numbers derived from plate No. 2. (see 65,) are most to be depended upon, and the agree- ment of the different series made with dark heat is highly sa- tisfactory. The numbers correspond to those of the last column in the example of (71). Mica Plate, No. 1. Retardation for Light, Ratio of Total Polarization and or o — e = '00004 inch. Depolarization or F* : E'^. Number of Comparisons. Argandlamp, 4 100:80 Incandescentplatinum, ... 4 100:78 Brass about 700°, 4 100:69 Mica Plate, No. 2. Retardation for Light, or o — e = -00002 inch. Argandlamp, 3 100:66 Incandescentplatinum,... 6 100:47 Brass about 700°, 7 100 : 52 Ditto, 4 100:51 Mercury about 500°, ... 5 100 : 52 In discussing these observations, it would be necessary to at- tend to the remark of (73), respecting the want of homoge- neity in the heat. 75. From the last series it appears that a plate of mica which transmits by polarized light (when the polarizing plates are crossed) red of the first order, almost exactly circularly polar- izes obscure heat, for it depolarizes half the heat. The cha- racteristic property of circularly polarized light was observed, viz. that little or no difference of result was obtained whilst the mica film was interposed (its principal section being inclined 45° to the plane of polarization), whether the analysing plate was at 0° or 90°. With incandescent platinum the effect is exceedingly striking ; for, if the mica film be at 0°, the po- larizing effect on crossing the plates is about 40 per cent, of the whole. 76. It is almost unnecessary to add, that what we have now said, inferring the undulatory theory of light to be true, might be translated into the language of the Newtonian theory of emission. 77. In conclusion, I would recapitulate the chief results at which I have arrived*. * These conclusions were stated nearly in their present form (excepting the 6th), to the Royal Society [of Edinburgh] at their meeting of the 5th January. The whole of the experiments detailed in this paper (excepting only the repetition of M. Melloni's experiment on the refraction of heat (16), were made between the 22nd November and the 16th January, but all the general consequences had been clearly made out before the close of 1834. Royal Society. 371 1 . Heat, whether luminous or obscure, is capable of polari- zation by tourmaline. 2. It may be polarized by refraction. 3. It may be polarized by reflection. 4. It may be depolarized by doubly refracting crystals. Hence, 5. It is capable of double refraction, and the two rays are polarized. When suitably modified, these rays are capable of interfering like those of light. 6. The characteristic law of depolarization in the case of light holds in that of heat, viz. that the intensities in rectan- gular positions of the analysing plate, are complementary to one another. 7. As a necessary consequence of the above, confirmed by experiment, heat is susceptible of circular and elliptic polari- zation. 8. The undulations of obscure heat are probably longer than those of light. A method is pointed out for deducing their length numerically. 78. Of the evidence for these conclusions I have enabled the reader to judge, by specifying numerical results. But I must further add, that all the principal conclusions were ar- rived at by the indications of the galvanometer, observed by the naked eye, including the chief phaenomena of depolariza- tion. Since I thought of the method of magnifying the divi- sions (described in (5),) I had little else to perform than the agreeable task of verifying and defining my first conclusions. Edinburgh, 19th January, 1835. LX. Proceedings of Learned Societies. ROYAL SOCIETY. 1835, A PAPER was read, entitled, " On the probable Posi- Feb. 19. — -^ tion of the South Magnetic Pole." By Edward Rudge, Esq., F.R.S., &c. The recent discovery of the site of the North Magnetic Pole, which has resulted from the experiments of Capt. James Ross, suggested to the author the inquiry whether any similar indications of an ap- proach to the South Magnetic Pole can be gathered from any obser- vations now on record. With this view a table is given of the obser- vations made by Tasman in 1642 and 1643, during his voyage of discovery in the Southern Ocean, extracted from his journal ; from which it appears that he on one occasion noticed the continual agita- tion of the horizontal needle, in south latitude 42° 25', and longitude from Paris 1 60°. On the presumption that the South Magnetic Pole was at that time near this spot, and that it has since been retrograd- ing towards the East, the author conjectures that it will now be found 3 B2 372 Royal Society, in or about the 43rd parallel of south latitude j and to the south-east of the Island of Madagascar, a situation extremely convenient for ascertaining its exact position, which he considers as an object of great theoretical as well as practical importance. The reading of a paper was then commenced, entitled, " An Ex- perimental Inquiry into the Cause of the grave and acute Tones of the Human Voice." By John Bishop, Esq. Communicated by P. M. Roget, M.D., Sec. U.S. February 26. — The reading of a paper, entitled, " An Experimental Inquiry into the Cause of the grave and acute Tones of the Human Voice." By John Bishop, Esq. Communicated by P. M. Roget, M.D., Secretary to the Royal Society, was resumed and concluded. The author considers all the theories hitherto proposed respecting the functions of the organs of the human voice, as not only unsatis- factory, but as being founded on erroneous views. He shows that the modulation of the tones of the voice is not the result of variations either exclusively in the length or in the tension of the vocal chords, or in the size of the aperture of the glottis, or in the velocity or the temperature imparted to the air in its transit through these passages. He regards the organs of the voice as combining the properties of wind and of stringed musical instruments ; and shows, first, that for the pro- duction of any musical tone it is necessary that the vocal chords should previously be made mutually to approximate ; and, secondly, that the muscular forces acting on the arytenoid cartilages and vocal chords are adequate not only to resist the pressure of the column of air issu- ing from the lungs, but also to render either the whole or certain portions of the vocal chords susceptible of vibration when traversed by the current of respired air. In proportion as these parts of the vocal chords, thus rendered vibratory, increase in length, the number of their vibrations, performed in a given time, diminishes, and the tone of the sound emitted becomes, in consequence, more grave; and, conversely, the tone is more acute as the vibrating portions of the chord are shorter : these phsenomena being precisely analogous to those which take place in stringed musical instruments. The author concludes his paper with some observations on the comparative physiology of the voice; and on the extensive range and superior excellence of this faculty in man. March 5. — A paper was read, entitled, " A new Method of dis- covering the Equations of Caustics." By G. H. S. Johnson, M.A., Tutor of Queen's Collea^e, Oxford. Communicated by the Rev. Baden Powell, M.A., F.R.S. Peculiar difficulty has hitherto attended the determination of the equation of the curve formed by the perpetual intersection of rays, which, diverging from a luminous point, are reflected by a polished surface of a given curvature. Curves of this description have been denominated caustics ; and the method usually employed to discover their polar equations, or the relation between the radius vector of any point of the curve and the tangent at that point, is both long and in- elegant, and is considered by the author as involving considerable inaccuracy of reasoning. He proposes, therefore, to substitute a new Mr. J. V.Thompson on the Metamorphosis oftheCirripedes. 373 method of investigation, by taking the polar equation of one of tiie reflected rays, and differentiating this equation with respect to the arbitrary quantities solely which determine its position, and thus ob- taining the polar co-ordinates of the point of intersection of two con- secutive lines j and finally, by elimination, the equation of the curve in which all such points are found. He is thus led to results remark- able for their simplicity, elegance, and generality : and he gives par- ticular applications of his method, exemplifying the facility with which it effects the solution of problems extremely difficult of management by the ordinary methods hitherto employed. His method is also ap- plicable to the determination of the equations of the evolutes of curves, and to various other problems of a similar nature, A paper was also read, entitled, " Discovery of the Metamorphoses in the second Type of the Cirripedes, viz. the Lepades, completing the Natural History of these singular Animals, and confirming their affinity with the Crustacea." By J. V. Thompson, Esq., F.L.S., Deputy Inspector General of Hospitals. Communicated by Sir James Macgrigor, Bart., M.D., F.R.S. The discoveries madeby the authorof theremarkablemetamorphoses which the animals composing the first family of the Cirripedes, or Ba- lani, undergo in the progress of their developement, and which he has published in the third number of his Zoological Researches (p. 76), are in the present paper, which is intended as a prize Essay for one of the Royal Medals, followed up by the report of his discovery of similar changes exhibited by three species of two other genera of the second tribe of this family, namely, the Lepades. The larvae of this tribe, like those of the Balani, have the external appearance of bivalve Monoculi, furnished with locomotive organs,in the form ofthree pairs of members, the most anterior of which are simple and the other bifid. The back of the animal is covered by an ample shield, terminating anteriorly in two extended horns, and posteriorly in a single elongated spinous process. Thus they possess considerable powers of locomotion, which, with the assistance of an organ of vision, enable them to seek their future per- manent place of residence. The author is led from his researches to the conclusion that the Cirripedes do not constitute, as modern na- turalists have considered them, a distinct class of animals, but that they occupy a place intermediate between the Crustacea decapoda, with which the Balani have a marked affinity, and the Crustacea en- tomostraca, to which the Lepades are allied ; and that they have no natural affinity with the Testaceous MoUusca, as was supposed by Linnaeus, and all the older systematic writers on Zoology. March 12. — Continuation of a former paper *' On the twenty-five feet Zenith Telescope, lately erected at the Royal Observatory j '* by John Pond, Esq., F.R.S. , Astronomer Royal. For determining the place of any star passing the meridian near the zenith, at the Royal Observatory at Greenwich, three different me- thods may be employed : first, by means of the mural circles ; se- condly, by the zenith telescope, used alternately east and west; and lastly, by means of a small subsidiary angle, as described by the au- thor in a former paper. The details of computations made according 374 Royal Society. to each of these three methods are contained in the present paper j from which it appears that they all give results nearly identical ; and that, when the observations with the two circles are made with suf- ficient care, the greatest error to be apprehended does not exceed the quarter of a second. *' Remarks towards establishing a Theory of the Dispersion of Light." By the Rev. Baden Powell, M.A., F.R.S., Savilian Professor of Geometry in the University of Oxford. In an abstract of M. Cauchy's Theory of Undulations, published hi the London and Edinburgh Journal of Science*, the author of the present paper deduced a formula expressing precisely the relation between the length of a wave and the velocity of its propagation ; and showed that this last quantity is, in fact, the same as the reciprocal of the refractive index. The author here examines, by means of this formula, the relation between the index of refraction and the length of the period, or wave, for each definite ray, throughout the whole series of numerical results which we at present possess ; and the conclusion to which he arrives from this comparison, for all the substances examined by Frauenhofer, viz. for four kinds of flint glass, three of crown glass, water, solution of potash, and oil of turpentine, is that the refractive indices observed for each of the seven definite rays are related to the length of waves of the same rays, as nearly as possible according to the formula above deduced from Cauchy's theory. For all the media as yet accurately examined, therefore, the theory of undulations, as modified by that distinguished analyst, supplies at once both the law and the explanation of the phaenomena of the di- spersion of light. March 19. — A paper was read, entitled, " Some Account of the Eruption of Vesuvius, which occurred in the month of August, 1834, extracted from the manuscript notes of the Cavaliere Monticelli, Foreign Associate of the Geological Society, and from other sources ; together with a Statement of the Products of the Eruption, and of the Condition of the Volcano subsequently to it." By Charles Dau- beny, F.R.S., F.G.S., and Professor of Chemistry in the University of Oxford. It appears, from the information collected by the autlior, that for a considerable time previously to the late eruption of Vesuvius, stones and scoriae had been thrown up from the crater, and had accumulated into two conical masses, the largest of which was more than two hun- dred feet in height. On the night of the 24th of August last, after the flow of considerable currents of lava, a violent concussion took place, followed by the disappearance of both these conical hillocks, which, in the course of a single night, were apparently swallowed up within the cavities of the mountain. Fresh currents of lava continued to flow for several days subsequently, destroying about 180 houses, spreading devastation over a large tract of country, and destroying all the fish in the neighbouring ponds and lakes. After the 29th of August, no further signs of internal commotion were manifested, with the ex- ception of the disengagement of aqueous and aeriform vapours from the * See our present volume, p. \Qct seq. Geological Societtj. 375 crater, a phsenomenon which, in a greateror less degree, is at all times observable. The author descended twice into the interior of the crater, which then presented a comparatively level surface j its sides con- sisting of strata of loose volcanic sand and rapilli, coated with saline incrustations of common salt, coloured red and yellow by peroxide of iron. The vapours which issued from various parts of the surface, collected and condensed by means of an alembic introduced into the ground, were found to consist principally of steam and muriatic acid, with only a slight trace of sulphureous or sulphuric acids. From a trial with solution of barytes, the author concludes that carbonic acid was also exhaled, but neither nitrogen nor sulphuretted hydrogen appeared to form any part of the gas emitted. The steam issuing from the lava contained both free muriatic acid and also muriate of ammonia, which latter salt could not be detected in the gas from the volcano itself. The author conceives that these volatile principles are entangled in the lava, and are subsequently disengaged. March 26. — " On the Temperature of some Fishes of the Genus Thynnus." By John Davy, M.D., F.R.S., Assistant Inspector of Army Hospitals. Tlie author had occasion to observe, many years ago, that the Bonito [Thynnus pelamys, Cuv.) had a temperature of 99^ of Fahr. when the surrounding medium was80°-5, and that it, therefore, constituted an ex- ception to the generally received rule that fishes are universally cold- blooded*. Having found that the gills of the common Thunny of the Me- diterranean {Thynnus vulgaris, Cuv.) were supplied with nerves of un- usual magnitude, that the heart of this latter fish was very powerful, and that its muscles were of a dark red colour, he was led to conjec- ture that it might, like the Bonito, be also warm-blooded ; and this opinion is corroborated by the testimony of several intelligent fisher- men. The author endeavours to extend this analogy to other species of the same family, which, according to the reports of the fishermen of whom he made inquiries, have a high temperature, and in whose internal structure he noticed similar peculiarities as in the Thunny ; namely, very large branchial nerves, furnished with ganglia of consi- derable size. In this respect he considers that in these fishes the branchial system of organs makes an approximation to the respiratory apparatus of the Mammalia, and that it probably contributes to the elevation of temperature, resulting from the more energetic respira- tion which he supposes to be exercised by these organs. He, how- ever, thinks it not improbable that these fish may possess means of generating heat peculiar to themselves, and of which at present we have no adequate idea. He conceives that the situation of the kid- neys, of which a considerable portion is even higher than the stomach, and posterior to the gills, and which are of large size, and well sup- plied with nerves and blood-vessels, may possibly act a part in the production of an elevated temperature ; but, on the whole, he is dis- posed to ascribe the greatest share of this effect to the superior mag- nitude of the branchial nerves. * See Mr. Brayley's paper on the Distribution of the Powers of pro- ducing Heat and Light among Animals, in our last Number, p. 245. 376 Geological Society, GEOLOGICAL SOCIETY. Feb. 4. — A paper was read, " On certain Coal Tracts in Salop, Worcestershire and North Gloucestershire," by Roderick Impey Murchison, Esq. V.P.G.S. Pursuing the inquiry in descending order, commenced at the last Meeting, the author calls attention to certain undescribed carboni- ferous districts, the outlines of which he has laid down upon the Ordnance Maps. I. " Shrewsbury or upper Coal-measures with Jreshivater Limestone." The author takes this opportunity of showing, that the coal- measures near Shrewsbury, which he formerly described* as con- taining a subordinate band of lacustrine limestone, pass up con- formably into the lower member of new red sandstone, and are thus proved to constitute the uppermost portion of the carboniferous series. He has this year discovered this freshwater limestone (with the same minute Planorbis, &c.,) in a thin zone of coal-measures extending from Tasley near Bridgnorth to Coughley near Broseley, where the strata, like those near Shrewsbury, also dip conformably beneath the lower new red sandstone. Mr. Prestwich has ascertained that some of the great beds of coal of the Broseley and Colebrook- dale field are worked beneath this limestone. II. Western Coal-Jield of Salop. The Oswestry coal-field, lying on the western borders of Shrop- shire, is completely separated from that of Shrewsbury, and is the southern termination of the carboniferous zone, which extends from Flintshire by Ruabon and Chirk. It is of small extent, and little productive, containing only one bed of good coal. The millstone grit, which rises from beneath it on three sides, is remarkable for containing beds of cherty breccia, courses of sandy, encrinital lime- stone, and in the lower portion strata of thick-bedded, red sandstone, in parts undistinguishable from the new red sandstone. The carbo- niferous limestone beneath this red sandstone, is exhibited on a very large scale in the fine escarpments of Llanymynech, Porth-y-wain and Treflach. The upper part is somewhat magnesian, and con- tains few fossils, with thin veins of copper ore; the lower is a fine subcrystalline limestone, in which are found Producta hemisjphcBrica, the large basaltiform Coral, and many other fossils characteristic of the formation. Faults are numerous, and in the principal one run- ning from north by east to south by west, the coal is upcast 180 yards. These dislocations increase as they rise upon the hill sides, and decrease as they range towards the plains of Shropshire. III. " Central and Southern Coal-fields qf Salop T The author mentions that he has accumulated many new facts respecting the coal-fields of the Clee Hills, since his communications in 1832, the principal of which are. That at the Titterstone Clee, the new works established by Mr. Lewis, have proved the existence of productive coal seams under the Hoar Edge, on the western side of * Geol. Proceedings, vol. i. p. 472. Geological Society, 377 the great basaltic dyke. He corrects the observation formerly made that some of the faults which affect the elevated tract of the Brown Clee Hills are the fissures of eruption of the basalt which crowns their summit. These faults, running from north to south and tra- versed by others trending from east to west, are all upcasts, and contain no basaltic matter, the chief eruption of which is supposed to have taken place at the north end of the Abdon Burf. Various details are given respecting this poor coal tract, which, though interesting in the theory of the formation of coal basins, cannot be included in an abstract. The mountain limestone is entirely absent, the coal resting on old red sandstone, as previously remarked by Mr. Wright of the Ordnance Survey.* IV. Forest of Wyre, In this tract are comprehended all the carboniferous strata ranging from two miles south-west of Bridgnorth to the Abberley Hills, the central and broadest portion of which is called the Forest of Wyre. The outline of this coal tract is very irregular, and the measures rest upon and are surrounded by the old red sandstone, except near Bewdley, where they are flanked by the new red sand- stone, and on the sides of the Abberley Hills, south of the Hundred- house, where they have been deposited in thin patches upon transi- tion rocks. Accounts are given of the different seams of coal and layers of ironstone which have been worked, near Deux Hill, Billings- ley, Stanley, Mamble, Pensax, &c. The greater part of these works, including all the deep shafts, are abandoned, owing chiefly to the poor and pyritous quality of the coal. Sweet coal is of rare occurrence, though some thin beds occur at Lower Harcourt near Kinlet. These sulphureous coals are little used, except for drying hops and burning lime; but the sandstones, though only par- tially quarried, afford excellent building material. Some peculiar conglomerates, having a matrix of decomposed trap, occupy the lower beds of the series south of Bewdley. In general the strata are much disturbed, and the structure of the country is rendered obscure by protruded bosses of the underlying old red sandstone and its associated marls and cornstone. In some cases the old red sandstone (as on the Borle Brook), constitutes the sides of narrow ravines, on the flanks and in the hollows of which the coal is thrown off at high angles of inclination. At Kinlet the coal-measures are perforated by a wide and extensive mass of basalt, the structure of which has been previously described f, and in the neighbourhood of this rock they are much hitched and broken, the sandstones being in parts converted into a hard siliceous rock called White Jewstone. At Arley, on the Severn, coal-measures, surrounded by old red sandstone, extend in a peninsulated form from the left bank of the river, and are bisected by the trap dyke of Shatterford. Another large mass of trap consisting of concretionary compact felspar was last year discovered by the author at Church Hill, 5 miles south of Cieobury Mortimer, but its relations to the adjoining * Geol. Proceedings, vol. ii. p. 7. t Geol. Proceedings, vol. ii. p. 92. Third Series, Vol. 6. No. 35. May 1835. 3 C 378 Geological Society* coal-field cannot be detected. The great fault at Stanley, near Higley on the Severn, has been caused by an upcast of the old red sandstone, which there occupies both banks of the river, abruptly cutting off the coal-measures. Allusion is then made to a short no- tice* of this tract, in which concredonary calcareous rocks are de- scribed as being subordinate to these coal-measures, but Mr. Mur- chison shows that these rocks are nothing more than protruding masses of cornstone of the inferior old red sandstone. He further describes, in detail, a section extending from one of these masses of concretionary limestone near Kinlet to Prescot Bridge. In this sec- tion there is a full development of the superior group of the old red sandstone, which although incoherent and of a yellow colour, and therefore unlike the prevailing rocks of that formation, is seen to pass upwards into a conglomerate, and dip under the true carbo- niferous limestone of Orelton. It is this tract of old red sandstone which separates the stinking-coal-fields of Bewdley Forest from the productive coal-fields of the Clee Hills. V. <' Coal-field ofNevoent, North Gloucestershire." The carboniferous strata are here so little developed as scarcely to entitle them to the name of a coal-field, being composed of merely a ^Q^ carbonaceous beds, interposed between the new and old red sandstones. In the vicinity of the town of Newent, where the formation is most expanded, four thin seams of coal were formerly worked, which were separated from each other by only a ievf yards of shale. In some cases the coal was extracted from beneath the new red sandstone. The extension of these carbonaceous strata is cut off in the south and south-west by the transition rocks of May Hill ; while to the north they gradually taper away, and are abso- lutely seen to thin out between the escarpment of new red sand- stone and the argillaceous marls of the old red ; hence the author concludes that the Newent coal strata were originally deposited upon old red sandstone, in a similar manner to those of the Brown Clee Hills, the Forest of Wyre, ike, &c. In concluding his reports upon these detached coal-fields, the author gives the following as the positions which he has attempted to establish : 1st, The existence of a younger zone of coal, which contains a peculiar freshwater limestone, and passes upwards into the oldest strata of the new red sandstone, (Shrewsbury coal-field.); and down- wards into the inferior coal strata of Coalbrook Dale. 2ndly, That the inferior coal strata were deposited in some parts upon mountain limestone and in others upon the old red sandstone and transition rocks. 3rdly, That the Clee Hill fields exhibit only the lower system, graduating down in two situations to mountain limestone, and in others resting upon old red sandstone. 4«thly, That in the Brown Clee Hills, the Forest of Wyre, and at Newent, the carbonaceous matter was originally deposited upon the old red sandstone. * Geol. Proceedings, vol. ii. p. 20. Linncean Society, 379 5thly, That in some of the poor and ill-consolidated coals, particu- larly in the upper zone, the traces of vegetable organization are so distinct, that even the generic and specific characters of the plants can be recognised in the coal itself. Lastly, That wherever the mountain limestone has been inter- polated between the bottom coal grits and the old red sandstone, it can invariably be traced to thin out and disappear within a very small area ; and hence it is inferred, that as calcareous matter ap- pears never to have been elaborated in these regions, except at wide intervals and in minute quantities, mighty convulsions are not ne- cessary to account for the absence of the mountain limestone through such large carboniferous tracts. The coal-field of Oswestry is not included in the application of these inferences; for, like the great coal basin of South Wales, it has been deposited upon a thick girdle of carboniferous limestone. LINN^AN SOCIETY. March 3rd and 17th. — Read a paper by the Rev. Patrick Keith, F.L.S., on the Classification of Vegetables, — or Taxonomy^ as the writer proposes to call it. After noticing the limited and imperfect use of artificial methods of classification, as pointed out by Linnaeus himself, whose well-known maxim is ** Methodus naturalis ultimus botanices finis est et erit," Mr. Keith insists on the superiority of aji arrangement founded on general structure rather than numberof parts; and gives his opinion that there is but one system which is natural, and that that system is Jussieu's. After enumerating some of the principal supporters of this system, he mentions our celebrated countryman Brown as at the head of those by whom it has been elucidated and per- fected ; — paying at the same time a deserved tribute to the merits of Mr. Don. He then proceeds to comment upon writers who in his judgement have innovated upon Jussieu's nomenclature and arrange- ment ; and, after some observations on Professor Lindley's Nixus Plantarum, and the circular arrangements, concludes with a tabular sketch intended to adapt the system of Jussieu to the present state of botanical knowledge, without innovating upon its principles. April 7th. — Read a communication by George Bentham, Esq., F.L.S., entitled, " On the Eriogoneae, a tribe of the order Polygoneae." This group, which is exclusively American, is distinguished from the rest of the order by the presence of an involucrum, and by the entire absence of the sheathing stipules from the leaves. The Erio- gonecE agree with Rheum and Oxyria in having a straight embryo placed in the axis of the albumen. The group consists of three ge- nera, namely, Eriogonumy distinguished by its many-flowered invo- lucrum ; Chorizanthe, a genus proposed by Mr. Brown, and distin- guished from the former by having a single-flowered involucrum ; and lastly, Mucronea, characterized by its bidentate involucrum, composed of two confluent bractes. Mr. Bentham describes twenty-four species of Eriogonum, eleven of Chorizanthe^ mostly from Chile, and one of Mucronea. The great accession of new species is chiefly the result of the labours of the late Mr. Douglas in California, and of Mr. Cuming in Chile. 3 C 2 3S0 Zoological Society. April 21. — Reatl *' Observations on the Species of Fedia.** By Joseph Woods, Esq. F.L.S. This genus was included by Linnaeus in Valeriana^ and several of the species were conibined by him under the denomination of V. Lo- custa, erroneously considering them as forming but varieties of one species. The genus is distinguished from Faleriana by habit, and by the structure of its fruit, which is always destitute of the feathery crown peculiar to the former. The far greater part of the species are natives of Europe, and Mr. Woods in the paper before us gives the character of twenty-one species, arranged according to the divisions proposed by De CandoUe, and he has united with them the Fedia CornucopicB separated by De Candolle as a distinct genus, from its corolla being furnished with a lengthened filiform tube and an irregu- lar limb. The paper is illustrated by figures of the fruit of tKe various species. ZOOLOGICAL SOCIETY. [Continued from p. 230.] October 14, 1834. — A letter was read, addressed to the Secretary by Sir Robert Ker Porter, Corr. Merab. Z.S., dated Caraccas, July 24, 1834. In reference to the Tortoises (Testudo Carbonaria, Spix,) presented to the Society by the writer in the spring of the present year (see Lond. and Edinb. Phil. Mag. vol. v. p. 233), it stated that they are regarded as a great delicacy at Caraccas, and sold as such in the market. A letter was read, addressed to the Secretary by the Hon. Byron Cary, dated His Majesty's ship Dublin, Sept. 25, 1834,^ving some particulars relative to a large specimen of the Tortoise from the Gal- lapagos Island, presented by the writer to the Society. The spe- cimen weighs 187 lbs. and measures in length, over the curve of the dorsal shell 3 feet 84- inches, and along the ventral shell 2 feet 3^^ inches, its girth round the middle being 6 feet 3-f inches. It is consequently much smaller than several specimens of the Indian Tor- toise from the Seychelles Islands which have at different times been exhibited in the Society's Garden; the weight and measurements of one of which are given in our report of the Society's Proceedings on the 9th of July 1833 ; Lond. and Edinb. Phil. Mag., vol. iii., p. 300, The lateral compression of the anterior part of the dorsal shell, and the elevation of its front margin, by which the Gallapagos Tortoise is distinguished from the Indian, are in this specimen strongly marked. Some notes by Mr. Martin of the dissection of a specimen of the Mangue (Crossarchus ohscurus, F. Cuv.) were read. " The dissection was strongly confirmatory," Mr. Martin observed, " of the justice of the position claimed for the animal, notwith- standing its plantigrade mode of progression, between the Ichneumons and the Suricates. To the latter indeed it bears in its general exter- nal aspect and characters a marked affinity; in both we find the pupil circular, and the muzzle elongated, pointed, and moveable. Nor is there much less con-espondence in their general anatomy." The de- tails are given in the * Proceedings ' of the Society. A collection was exhibited of skins of Birds, formed by B. H. Hodgson, Esq., Corr. Memb. Z.S., in Nepal, and presented by him Zoological Society, S81 to the Society. These birds were brought under the notice of the Meeting by Mr. Gould, who, at the request of the Chairman, pointed out the most interesting among them, both as regarded the Society's collection, and with reference to their novelty or the peculiarities of their form. As, however, Mr. Hodgson himself purposes to describe at length the characters and habits of the several species in his pro- posed ' Zoology of Nepal,' Mr. Gould abstained from entering more particularly into those topics. A paper was read " On Clavagella, by W. J. Broderip, Esq." It was accompanied by drawings illustrative of the new species de- scribed in it. The author commences by a history of the genus from the time when Lamarck established it for the reception of four fossil species, two of which he had previously referred to his genus Fistulana. A recent species was subsequently described and figured by Mr. G. B. Sowerby.in his 'Genera of Recent and Fossil Shells,' under the name of Clav. aperta ; and a second recent species, Clav. Australis, has since been described and figured by the same conchologist ; M. Au- douin has noticed another recent Shell which he refers to this ge- nus ; and some details have been published by M. Rang of an ad- ditional recent species, his Clav. Rapa. The collection of Mr. Cum- ing furnishes another recent species, the anatomy of which formed the subject of a paper read by Mr. Owen at the last Meeting of the Society; there exists yet another in that of Mr. Isaac Lyon Gold- smid ; and another in those of Mr. Cuming and Mr. Miller. A close examination of the recent species which he has observed has convinced Mr. Broderip that although one valve of the shell is always fixed or imbedded in the chamber formed in the hard sur- rounding substance, the tube is not necessarily continued into a com- plete testaceous clavate shape, and that consequently the character assigned by Lamarck to the genus requires emendation. The fixed valve is in all these species continued on to the tube. In Mr. Cuming's the perforated shelly plates are situated not far from the throat of the tube, one on either side ; while in Mr. Gold- smid's the perforated plate is single, and seated at the anterior or greater end of the ovate chamber, being in the smaller individual joined laterally to the anterior ventral edge of the fixed valve, and in the larger one wholly isolated from it. In all the specimens the anterior edge of the fixed valve is surrounded by the naked wall of the chamber. After remarking on the difficulty of clearly defining species where the roughness or smoothness of the surface of the shell and even its shape may depend upon the greater or less degree of hardness of the material of which the chamber is formed ; where colour also is absent ; and from specimens of which the tubes are broken ; Mr. Broderip proceeds to suggest the following distinguishing characters. The first two may, he remarks, hereafter prove to be mere varieties, although he is strongly disposed to regard them as constituting distinct species : Clavagella. elongata. Clav. camerd elongato-ovatd ; valvd liberd SS2 Zoological Society, elongatd, suhtrigond, convexd, extern^ concentric^ vald^ rugosd, intiis nitente ; umbone acuto, Hab. in. Oceano Pacifico ? Mus. Goldsmid. The wall of the coral chamber against which the free valve rested gives as exact an impression of the external rugosities of that valve as if the valve had been applied to a surface of wax. Clavagella lata. Ciav. camera rotundato-ovatd ; valvd liberd latiusculd, subtrigond, subconvewd, externe concentrice rugosd, intils nitente ; umbone subrotundato. Hab. in Oceano Pacifico. Mus. Cuming. Both valves are nacreous internally ; and the muscular impres- sions, especially in the fixed valve, are very strong. Clavagella Melitensis. Clav. testd subrotundatd, rugosd, intiis subnitente ; tubo longitudinaliter corrugate. Hab. ad Melitam. Muss. Cuming, Miller. It is not impossible, from its locality, that this may turn out to be M. Audouin's species, if that should prove to be a true Clavagella. M. Sander Rang's remarks, however, go far to show that a Sicilian Shell referred to this gen\is, has been incorrectly so referred, in as much as it has no fixed valve. The one described above has the fixed valve continued on to the shelly tube as in the other recent species of the genus Clavagella. Mr. Broderip conjectures that Clavagella may be in its very young state a free Bivalve, floating at large until it arrives at some vacant hole that suits it, when it attaches one valve to the wall of the hole, and proceeds to secrete the tube or siphonic sheath, to enlarge the chamber according to its necessities, and to secrete the shelly per- forated plate which is to give admission to the water at the prac- ticable part of the chamber. The excavation may probably be as- sisted by the secretion from the glands observed by Mr. Owen, and evidently cannot be efi^ected in the greater end of the chamber by mere mechanical attrition ; but the solvent secrotion must be one of extensive powers to act on such different substances as siliceous grit, the coral of an Astrceopora, calcareous grit, and argillo-calca- reous tufa, in which respectively were found the Clav. Australis, Clav. elongata, Clav. lata, and Clav. Melitensis. Adverting to the different depths at which these several species were found, which varied from near low- water mark to sixty-six feet, Mr. Broderip remarks, that inferences as to the state of submersion of a rock during the lifetime of the fossil species which there occur, ought consequently to be made with caution by the geologist. In conclusion he observes, that though the genus Clavagella is in its recent state at present rare, it is in all probability widely dif- fused ; and suggests to collectors a careful examination of masses of coral and submerged perforated rocks with a view to the further elucidation of the habits and structure of these and other interest- ing animals. Zoological Society, 383 October 28. — Living specimens were exhibited of a species of Bee from South America, together with portions of its Comb, contained in the fissure of a log of wood. They were presented to the Society by Mr. Bigg, who stated, in a note accompanying the specimens, that they were found about three weeks since on spUtting a log of peach- wood from the Brazils for the use of a dye-house, on the premises of Mr. Applegath, a calico-printer at Crayford in Kent. The wood had been previously lying in the docks, and had been perhaps eighteen months from the Brazils. Mr. Curtis, to whom specimens were submitted for examination, states that they belong to the genus Trigona, Jur., and form a very pretty and apparently undescribed species. Mr. Yarrell exhibited preparations of both sexes of Syngnathus Acus, Linn., and Syngn. Typhle, Ej., in illustration of the following extract from the manuscript notes of the late John Walcott, Esq., author of ' A Synopsis of British Birds,' * History of Bath Fossils/ ' and * Flora Britannica Indigena.' This manuscript, which is volu- minous, and relates wholly to British Fishes, was written during the author's residence at Teignmouth, in the years 1784 and 1785, and has been forwarded by his son William Walcott, Esq., of South- ampton, to Mr. Yarrell, for his use in a projected work on * British Fishes.' •' Syngnathus Acus and Typhle. — The male differs from the female in the belly from the vent to the tail fin being much broader, and in having for about two thirds of its length two soft flaps, which fold together and form a false belly. They breed in the summer, the fe- males casting their roe into the false belly of the male. This I have asserted from having examined many, and having constantly found, early in the summer, roe in those without a false belly, but never any in those with ; and on opening them later in the summer there has been no roe in (what I have termed) the female, but only in the false belly of the male." The specimens exhibited of females of Syngn. Acus and Typhle had no anal pouch, and the opened abdomen exposed two lobes of ova of large size in each. The anal pouch is peculiar to the males, and is closed by two elongated flaps. On separating these flaps and ex- posing the inside, the ova, large and yellow, were seen lining the pouch in some specimens, while in others the hemispheric depres- sions from which the ova had been but lately removed were very obvious. In each of these the opened abdomen exhibited true testes. Mr. Walcott adds : " They begin to breed when only between 4 and 5 inches long." A specimen oi Syngn. Acus, nearly 1 6 inches long, was exhibited, indicating, probably, its extreme growth. A female of the same species, only 4 inches long, was also shown, the abdo- men of which contained two lobes of enlarged ova, which, to all ap- pearance, would have been deposited in a few days. Specimens of males and females oi Syngn. Ophidion,liiim.,v/eTe also exhibited. In this species neither male nor female possesses an anal pouch, but the ova are carried by the male in hemispheric depres- sions on the external surface of the abdomen, anterior to the anus. 584? Zoological Society. All the specimens examined having these external depressions proved to be males, with the testes in the abdomen very obvious : those without external depressions proved to be all females, internally- provided with two lobes of enlarged ova. The males of this species, when taken by Mr. Yarrell from the sea, had one ovum of the size and colour of a mustard-seed fixed in each cup-shaped depression, but time and the effects of a long journey had removed them. Dr. Fleming in his 'History of British Animals,' page 176, states the length of Syngn. Ophidion at about 5 inches : some of Mr. Yarrell's specimens measured 9 inches. Mr. Yarrell further stated that the males of Syngn. Acus carry their living young in the anal pouch, even after they have been hatched there. He had been frequently told by fishermen that on opening them they had found the living young within the pouch, which they called the belly ; and that if these young were shaken out into the water over the side of the boat, they did not swim away, but when the parent fish was held in the water in a favourable position, the young would again enter the pouch. It was observed by M. Agassiz, that the fact of the males of cer- tain species of the genus Syngnathus carrying the ova in a peculiar abdominal pouch, after their exclusion by the female, had been no- ticed on the Continent by Eckstrom, Retzius, and MarckUn ; and that he had himself made the same observation. M. Agassiz exhibited drawings of several species of Lepisosteus, together with some of the details of their internal organization ; and, at the request of the Chairman, explained his views with regard to their systematic arrangement and structure, as well as to their rela- tions with various genera of fossil fishes, and the coincidence of some parts of their internal anatomy with that of Reptiles. He described two new species observed by him in the British Museum, taking his characters principally from the form and sculpture of the scales, the presence or absence of the short rays at the base of the caudal and other fins, and the variations in the form and disposition of the teeth. In reference to their internal structure, he particularly called the at- tention of the Meeting to the large and regular slit by which the swimming-bladder communicates with the pharynx ; which he re- garded as bearing even a closer resemblance to the entrance of the trachea of the pulmoniferous Vertebrata in general, than the aperture by means of which the lungs communicate with the pharynx in the Perennibranchiate Amphibia. He conceived, therefore, that the ana- tomy of these fishes offers a conclusive argument in favour of the theory, long since proposed, that the swimming-bladder of Fishes is analogous to the lungs of the other Vertebrata. He spoke of the num- ber of the csecal appendages as greater in Lepisosteus than in any other fish which he had dissected ; and referring to certain fossil bo- dies by which geologists have long been puzzled, and which have been regarded as fossil worms, he stated his opinion, from the close resemblance between the two, that they are in reality the csecal ap- pendages of the fossil fishes, in whose company they are generally found. Mr. Gray on the Animal of ArgonaUta. 38.5 Mr. Gray exhibited young shells of Argonauta Argo and Arg. hi- ans, with the view of calling the attention of the Society to a new argument in favour of the opinion that the animal (Ocythoe) found in the shells of this genus is parasitic. This argument is founded on the size of what Mr. Gray has termed the nucleus of the shell, viz, that original portion of it which covered the animal within the egg, and which is usually found to differ in surface and appearance from the remainder of the shell formed after its exclusion from the egg. In the specimens exhibited Mr. Gray described the nucleus as blunt, rounded, thin, slightly and irregularly concentrically wrinkled, and destitute of the radiating waves which are common to the adult shells of all the species of this genus. These waves he stated to commence immediately below the thin hemispherical tips, and he therefore entertained no doubt that those tips constituted the nucleus of the shell, and covered the embryo of the animal at the period of its exclusion from the egg. Judging from the size of this portion of the shell, which in one of the specimens measured nearly one third of an inch in diameter, and was consequently many times larger than, the largest eggs of the Ocythoe found within the Argonaut shells, Mr. Gray inferred that it must have been produced by an animal whose eggs are of much greater magnitude. The Ocythoe cannot therefore, he conceived, be the constructor of the shell, and its true artificer still remains to be discovered. Mr. Gray further remarked, with reference to Poll's statement that he had observed the rudiment of a shell on the back of the embryo of Ocythoe examined by him, that he has himself uniformly found, in all the eggs of Mollusca which he has examined, the shell well developed, even befoife the develop- ment of the various organs of the embryo. With respect to the ar- gument derived from the want of muscular attachment, he observed that the animal of Carinaria (to which he considered it probable that that of Argonauta is most nearly related), although firmly attached to the shell while living, separates from it with the greatest ease when preserved in spirits, being from its gelatinous nature very rea- dily dissolved. These circumstances, he conceived, might fairly ac- count for the animal of Carinaria having been, until very recently, unknowa, and for that of Argonauta still remaining undiscovered. November 11, 1834. — A specimen was exhibited of a species of Monacanthus, Cuv., remarkable for having on each side of the body, about midway between the pectoral and caudal fins, a bundle of long and strong spines directed backwards. The species was figured in Willughby's * Historia Piscium,' and a description of it by Lister is contained in the Appendix to that work ; but it appears not to have been noticed by subsequent observers, and to have been altogether overlooked or rejected by systematic writers. Lister's specimen of the Fish was preserved in the collection of William Courten, the founder of the museum which became subsequently the property of Sir Hans Sloane, and eventually formed the basis of the British Mu- seum : that brought under the notice of the Meeting belongs to the Museum of the Army Medical Department at Chatham, and was exhibited with the permission of Sir James Macgrigor. It was ac- Third Series, Vol. 6. No. 35. May 1835, 3 D 386 Zoological Socicfi/. companied by a description by StafF-Surgeon Burton, which was read. MoNACANTiius Hystrix. Mou. latevibus in medio G — l-spinosis, spinis validis longioribus. Guaperva Hystrix, List., in Will. Hist. Pise, App. p. 21. Tab.S. 2 1 . " Length 7 inches. Colour black. Skin crowded with rough grains ; a smooth spot behind the gills ; towards the tail assuming the charac- ter of rhomboid scales, but the granular form continued over the caudal fin. On the sides, about one third of its length from the tail, is fixed a cluster of six or seven strong free spines from 4^ to 1 inch in length, capable of erection and depression. " Dorsal spine very strong, about 1-^ inch long, sub triangular, with serrated edges, and grained, except towards the point : when not erected it is lodged in a deep groove on the back. Extremity of the pelvis salient, and terminating in two sharp short spines. Se- cond dorsal fin broad and 2 inches long ; anal similar, but shorter. " In front of the eyes a small /ossa covered with a membrane, ex- cept in its centre, where it is perforated by a minute olfactory fo- ramen. " Teeth in the upper jaw eight, the two middle incisors placed di- rectly in front of the second pair, in a groove of which they are lodged, so that no part of these last are visible externally, except a small process at the cutting edge ; the outer teeth trigonal. The teeth of the lower jaw differ materially from the generic character, their number being only four, of which the two middle ones are by far the largest in the mouth. On this account, and also on ac- count of the nature of its covering, — which partakes of the granular character of that oi Monacanthus smdAluterus, Cuv., and of the rhom- boidal scales of Balistes,^]., — this fish might be regarded as the type of a distinct subgenus among the Balistidce. " The strong dorsal spine, the spinous processes of the pelvic bones, and the cluster of lateral spines, added to the tough indu- j-ated epidermis of this fish, form an armour excellently adapted for its protection against its more powerful enemies. " It is an inhabitant of the Indian Ocean, frequenting the shores and coral reefs. The present specimen was brought from the Mau- ritius by Dr. Hibbert, Surgeon, 99th Regiment. This species is stated to be also found abundantly on the western coast of Australia, where it is known to the settlers by the name of " leather-jacket," — a denomination which is probably applied to it in common with other species of Balistidce." Mr. Gray exhibited a drawing of this specimen, and stated his intention of publishing a figure of it in the concluding Number of the ' Illustrations of Indian Zoology,' which is about to appear. Mr. Gray called the attention of the Meetmg to two new species of Sturgeon ; one from China, of which he exhibited a specimen, and the other from the Mississippi, of which he showed a drawing taken from a specimen in the British Museum. The former species belongs to the same section of the genus with the Acipenser glaher of Mar- gigli, characterized by its conical muzzle, and the smooth and silvery Zoological Society, 387 nature of the skin between its 5 rows of plates. It was sent to En- gland from China by Mr. John Russell Reeves, and was characterized by Mr. Gray as Acipenser Sinensis. The other species was stated by Mr. Gray to belong to a new sec- tion intermediate between the true Sturgeons and the Spatulariee, having a broad expanded muzzle, flat above, shelving on the sides, and concave, and furnished with a central ridge beneath. It was characterized as Acipenser cataphractus; Acipenser cataphractus, Rapp, MSS. Hab. in fluvio Mississippi. The exhibition was resumed of the Shells collected by Mr. Cuming on the Western Coast of South America, and among the Islands of the South Pacific Ocean. Those exhibited at the Meeting were ac- companied by characters by Mr. G. B. Sowerby, and comprehended the following apparently undescribed species of the genus Fissurella. Fiss. maxima (in some specimens the internal margin shows a very great development of crystalline structure), grandis (long. 4, lat 2-6 poll.), limbata (a representation of the inside of this shell has been given in Mr. Sowerby's ' Genera of Recent and Fossil Shells,' under the name of Fiss.picta, Lam., from which it is nevertheless very di- stinct), biradiata (Frembly MSS.), lata (approaches, in form and co- louring, very nearly to Fiss.picta, hscm.), pulchr a, oriens, Chilensis, obscura, virescens, nigro-punctata, macrotrema, affinis (Gray), micro- trema (the dorsal perforation so small, and the coloration so dark, that it is difficult at first sight to perceive it to be really a Fissurella), inaqualis. Pica, Chemnitzii (represented by Martini, I. t. xi. f, 100, whose figure is cited by Lamarck as a representation of Fiss. Grit. ^ -2 -I ^oi o2 -^i^^ ^, B ..P=^ (U Qt 03-0 ?o '. . 3 rt 05 -H jj - CM CO § C -§, ^^ oHH a. - . c . . . w^s WOOCCrHrt 2©)(M0»i CO C ^ 4) "< js-^ -.S >^C5 ""S; . 5 s 13 fi^-a >^ s|^-g 10 09 c i*»''oai •puo^ roo • C< •4soa « ? ee j-^r-^-rty, >5e8e8cccc>ccacec5ca s s s s s <« « «J w « "c5 '« 'rt u u u •puoT ij^_^^^^j^& E' I ^ ^' ^ s ^* i i s g d s ^' w «• g isog »p 'O lO VO 'P 2 0'^"^-^toiO'^"^iou:)»ou:)>j:iOio»o>o*oiriiotO'<*>-OTt'ioiOiriri0 o O^C c^6^0 O O O C O o O O O O 6^o^ .'^vor^OIO00O — r^iOt^- VO CI "^CN " — CO o^ao 0^'---7<7-9^•7*c^coo^(p^^■^•vo 6^o6^C^OO^C^liiig x,ui TPioccooiits. — Hist. Indie., p. 357. X 2 vols. 4to. London, 1807. § See Vincent's Voyage of Nearchus^ Pref., p. xi. 3 F 2 404 Mr. Beke ow the Historical Evidence of the Advance of and after an elaborate investigation of the subject he thus re- cords his own opinion : " I have no hesitation in subscribing to the stadium of 51 toises assigned to the journal by D'Anville, whether it be considered as a Greek or Indian standard * ; " to which he subsequently adds, " I am convinced that no other stadium known in Greece will apply to the journal of Nearchus ; and if it be not a Greek stadium, I know not what measure it can be, unless it be derived from India or Arabiaf." Upon the united authority, then, of D'Anville and Vincent, the stadium of Nearchus is to be taken as one of sixteen to a mile English ; whence it results that the 3300 stadia which Babylon, in that navigator's time, was distant from the sea, must be equal to two hundred and six miles and a half. Strange to say, however. Dr. Vincent, in a note upon the passage trom Arrian in his Voyage of Nearchus (p. Q5\ after remarking that " 3300 stadia make little more than 200 miles English, [whilst] the real distance by the river is more than 400," actually offers the conjecture, in direct opposition to his own conclusion, " May not Nearchus calculate this di- stance by stadia o^ eight to a mile J ?" Now, it appears to me that any mode of getting over the apparent difficulty, — even * Comni. and Navig. of the Ancients^ vol. i. p. 66. ^ Ibid., p. 67. % In my Origines Biblica (p. 20, note,) I cite this note of Dr. Vincent's, and comment upon it; upon which the writer of the criticism in the Quarterly Review remarks (p. 505), " On this doubt of a most erudite geo- grapher, so fatal to his theory, Mr. Beke cbserve8,*that * the accuracy of the mode thus adopted by the learned translator, and by geographers generally, of reconciling apparent discrepancies in the works of ancient writers, by varying the standard of measurement, may legitimately be questioned.' Is, then, Mr. Beke prepared to show that one uniform standard was adopted by ancient writers? or to solve upon any other hypothesis the countless contradictions which are found in the writings not merely of the Greek and Roman historians, but of the geographers themselves, and which have perplexed and often baffled the D'Anvilles, the Gosselins, the Rennells, and the Mannerts of modern days?" Had the reviewer understood the ground of my objection to Dr. Vincent's conjecture, he would have spared himself the trouble of these remarks; and had he but quoted correctly my cita- tion of Dr. Vincent's note, he would not have misled such of his readers as are not conversant with the subject, by giving them reason to imagine that there were any grounds whatever for his animadversions. I wrote, " Dr. Vincent. ..says 3300 stadia [of sixteen to a mile: see his Preface, p. xi.] make little more than 200 miles," &c., which passage the reviewer thus varies : " 3300 stadia (of 16 to a mile) make," &c., altogether sup- pressing the reference made by me to Dr. Vincent's Preface, by which the inconsistency of his doubt is made apparent. Far be from me the assump- tion of even attempting to solve the countless contradictions to which the reviewer alludes; but yet I will venture to assert that very many of those contradictions do not exist in the text of the Greek and Latin writers themselves, but have arisen solely from the erroneous construction put upon that text by the commentators. the Land upon the Sea at the Head of the Persian Gulf, 405 had it been by denying the authority of the passage in ques- tion, or by doubting the correctness of the information com- municated by Nearchus, — would have been far better than the one adopted by the learned translator, which has the effect of altogether invalidating the previous conclusion (so positively expressed,) of D'Anville and himself. And, in fact, Dr. Vin- cent appears to have entertained a feeling of this kind, when in another place he says, " I object to all measures of this sta- dium taken where Nearchus himself did not navigate, and I he- sitate about the measure of 3300 stadia from the mouth of the Euphrates to Babylon, stated as the assertion of Nearchus* " These objections, although in reality they cannot be main- tained, are in themselves not unreasonaljle : let us see how they are to be met. We fortunately possess an authority, indepen- dent of Arrian, who establishes that historian's correctness, upon this subject, in all points. This authority is Pliny — or rather Juba as cited by Pliny, — who states " Euphrate navi- gari Babylonem e Persico mari ccccxii. mill, passuum tradunt Nearchus et Onesicritusf." This passage from Pliny is, indeed, adduced by Mr. Carter as an authority against me, in as much as he says that Pliny " must have understood Nearchus's terms of distance better than we can." But the geographers to whom I have already referred have determined that a very different conclusion is to be drawn from Pliny's statement; it being remarked by Dr. Vincent that " M. D'Anville has shewn, that in the gulf of Persia Pliny read the same number of stadia as Arrian found in Nearchus ; and that, by estimating these at eight to a mile, he makes the distance nearly double what it is in re- alityX'^ It is evident, therefore, that Pliny's error is solely in the reduction of the stadia into Roman miles ; and the pur- port of the passage in question has consequently to be thus given : " Nearchus and Onesicritus state the distance from the Persian Gulf z/p the course of the river (Euphrate navigari) to Babylon to be 3300 stadia." Since then — upon the assumption, always, that D'Anville and Vincent are correct in their conclusion as to the length of the particular stadium employed by Nearchus, — the distance from Babylon to the sea by following the course of the Eu- phrates, in that navigator's time (B. C. 325), was only two hun- dred and six miles and a half, whilst in the present day it is as great as about 400 miles, it seems to me that we have no al- * Cotmn. and Navig. of the Ancients, vol. i. p. 55. t Hist. Nat.y lib. vi. cap. xxvi. X Comm. and Navig. of (he AnciientSy vol. i. p. 65. 406 Mr. Beke on the Historical Evidetice of the Advance of ternative but to attribute the difference between these two measurements to the gain of the land upon the sea during the intervening period of 2160 years; and as the distance in a straight line may be taken at about |ths of the measurement along the course of the river, the advance of the land, (as de- termined by this one authority,) may be computed at about 150 miles. We have now to consider the passage from Pliny respect- ing Charax * ; which, upon investigation, will be found to harmonize entirely with the inference which has thus been drawn from the statement of Nearchus. Two different mean- ings may be attributed to this passage. The first is, " that Charax when first built was ten stadia only from the shore, whilst hy the report of Juba in his time it was 50 miles, and in Pliny^s own time as much as 120 miles from the seaf." The other construction, which appears to be that of the old Italian version of Brucioli, is, " Charax was at first a port di- stant 10 stadia, or according to Juba 50 miles, from the sea: now [/. e, in Pliny's time] it is said to be 120 miles distant J." If the former translation be the true one, the whole di- stance mentioned by Pliny must have been gained by the land between the times of Alexander and that historian ; but, as- suming the latter construction to be the more correct of the two, the advance of the land will be reduced nearly one half; whilst the seemingly conflicting statements as to the original distance of Charax from the sea may be reconciled by sup- posing that city to have been erected ten stadia only from the shore at the confluence of the Tigris and Eulaeus, but at the distance of 50 miles from the sea itself. It is yet further to be considered whether Pliny, although entirely correct in his * "Prius fuit a litore stadiis x., et maritimum etiam ipsa inde portum habuit : Juba vero prodente, 1. mil. pass. Nunc abesse a litore cxx. mil. legati Arabum nostrique negotiatores qui inde venere, affirmant." — Hist, Nat., lib. vi. cap. xxvii. f The first impression made upon the mind at all times by an unqualified and indefinite expression is that it refers to the time at which it is made. Thus it was that in giving, in my Origines Biblicce (p. 21.), what I conceived to be the general sense of the passage in question, I said " in Juba*s time it was... 50 miles." The writer in the Quarterly Review is, upon this, pleased to say, " Mr. Beke is, no doubt, wrong in translating Juba prodente , in Juba's time." — As may well be imagined, I never intended those words as a translation, and the reviewer might with as much propriety have accused me of translating Legati Arabum. ..affirmant^ " in Pliny's time." J ** Primieramente fu marittima, lontana dal lito dieci stadij, ma secondo Juba, 50 miglia. Hora i legati degli Arabi, et i nostri mercatanti che vengono di la effermano essere lontana dal lito 120 miglia." — Historia Na- turale di C. Plinio Secondo^ tradotta per Antonio Brucioli : Venetia 1548, p. 148. the Land upon the Sea at the Head of the Persian Gulf. 407 assertion of the facts themselves, may not have committed some error in the reduction into Roman miles of the actual mea- surements reported to him, similar to that which he is shown to have fallen into with respect to Nearchus's statement of the distance from Babylon to the Persian Gulf; in which case, the difference between the two distances of Charax from the sea in the times of Alexander and Pliny respectively, would have to be reduced yet further. But be this as it may, it is indisputable that in Pliny's time so considerable an advance of the land upon the sea had taken place since the period when Charax was first built, as to make it a subject of particular observation, and to call forth from that intelligent and obser- vant investigator of the phaenomena of nature the pointed re- mark, that " in no part of the world had the land gained so largely or so rapidly upon the sea*." On the whole, then, the fact of a very considerable advance of the land at the head of the Persian Gulf must be consi- dered as established beyond dispute ; and if the distances men- tioned by Nearchus and Pliny be at all near the truth, and the reduction of them into English miles be calculated even approximately only, we are still enabled to form a tolerable idea of how extensive that advance must have been. In the present state, however, of our information upon the subject, it is advisable that no hasty conclusion be come to as to the precise extent of the advance, to determine which, it will, no doubt, be necessary that extensive local investigation should take pi ace f. Still, if these calculations at all approach the truth, the ex- treme probability — not to say more — of my hypothesis, that in the earliest post-diluvian ages the low lands in the neigh- bourhood of Hillah were covered with water, will become yet more apparent ; in which case the site of the tower of Babel, as I have suggested, must necessarily be looked for elsewhere ; and it will follow also that any attempts to identify Nimrod*s Babel with the Babylon of Nebuchadnezzar must be altogether unsuccessful; since, in fact, the erection of the latter city would have been physically impossible until a much later period,— * " Nee ulla in parte plus aut celerius profecere terrae fluminibus invectae.'* — Hist. Nat.., lib. vi. cap. xxvii. f I trust that considerable information concerning the early geography of the countries under discussion will be derived from the researches of my friend Col. Chesney and the other officers now engaged on the Eu- phrates expedition. Before Col. Chesney's departure I had the satisfac- tion of acquainting him with my opinion as to the physical changes which have taken place in these countries. 408 Mr. Beke 07i the Advance of the Land in the Persian Gulf. until the alluvial country upon which its ruins now stand had been formed and had become fit for habitation*. The history of Babylon, therefore, cannot possibly have any connexion with that of Nimrod and his immediate successors. Whilst upon this subject I gladly avail myself of the op- portunity afforded me of correcting an error in my Origines Bibliccs (p. 89). I have there said that " the proper grammati- cal construction of the words of the textf ^W^? ^*^l yatza Asshur) is ' went forth Asshur*, the word Asshur hemg the no- minative or subject of the verb." In this conclusion I adopted the version of the Septuagint, Josephus, the Vulgate, and the text of our received English translation, as also the opinion of by far the greater number of scholars who have investigated the subject X ; but, after deliberate consideration, I have no hesita- tion in stating, (notwithstanding this great weight of authority,) that I now entirely agree with those scholars who consider that the marginal reading of our authorized version, " he [2. e, Nimrod,] went out into Assyria," is to be preferred. Mr. Carter adopts this latter reading ; and a writer in the first number of Cochrane's Foreign Quarterly Review (p. 82), inculpates me for advocating the opinion which I here relin- quish. In consequence of this correction there is no neces- sity for imagining (as, under the influence of the same error, I have done, in Orig, Bibl., pp. 24 — 26,) that after the Di- spersion from Babel, Nimrod founded in the land of Shinar a second city, of the same name : on the contrary, the Scrip- tural narrative, according to the interpretation which I now consider to be the correct one, expressly tells us that he went out of that land into Assyria, where he founded Nineveh and the other cities which are named in the text. I am, Gentlemen, Your obedient servant, London, April 30, 1835. Charles T. Beke. * In my Ongines Biblicee (p. 66), I have given my reasons for placing the site of the tower of Babel in the north-western portion of Mesopo- tamia. Tn the same work (p. 259, note,) I have hinted at the possibility of the ruins at Hillah not being even those of Nebuchadnezzar's Babylon ; and 1 have since suggested to Col. Chesney that the actual site of that city may be some thirty or forty miles to the north-westward of Hillah ; in fact, not upon the present course of the Euphrates, but upon what is represented in the maps as having been an ancient branch of that river. f Gen. X. 11. t See upon this point Dr. Russell's Connection of Sacred and Profane History, vol. ii. pp. 2 and 43. [ 409 ] LXIII. Remarks on some curious Facts respecting Vision de- scribed in the Lond, and Edinb, Phil, Mag, for 1834. By Lewis Tonna. To the Editors of the Philosophical Magazine, Gentlemen, T HAVE just seen a letter from K. relating to " some cu- -■- rious facts respecting vision," which appeared in your Journal for November 1834. I will not trespass further on your pages than to state that for the last six years a similar difference in power of vision has existed in my eyes. By al- tering the axis of vision of the two eyes, and thus producing a double image of any object, the image offered by the left eye is even less than half the size of the one presented by the right eye. There is also a slight indistinctness in the image, independently of the reduction in size. This affection came on gradually, and was not produced by any disease, either con- stitutional or local, that I am aware of. Whether I am right in attributing this fact to an undue diminution of convexity in the left eye, similar to that habitual to old age, I know not. In a sound state of vision, it is doubtless by an habitual and imperceptible exertion of the brain that the images of- fered by the two eyes are made to coincide and produce the perception of one single image. In my case the impossibility of producing a coincidence of images of different magnitudes causes a general indistinctness of vision, and I can see objects clearer and better defined with the right eye alone than with both eyes ; but on applying a convex lens of great power (which I always use,) to the left eye, the distinctness is restored, and all colours immediately become more vivid. I should be glad to hear the opinion of persons better able than myself to judge of this phaenomenon, and whether the use of a lens is judicious. The expansion and contraction of the pupil on sudden exposure to changes of intensity of light, is more sluggish in the left or diseased eye than in the right one. This is the only external difference. I am. Gentlemen, yours, &c., United Service Museum, London, LewiS Tonna. April 16, 1835. \* We may now state that the author of the paper signed "K." above referred to, was the late lamented Capt. Kater, in whom the disease of vision it describes seems to have been the precursor of death. It was probably almost the last contribution to science of that distinguished natural philosopher. — Edit. Third Series, Vol. 6. No. 36. June 1835. 3 G [ 4.10 ] LXIV. Experimental Researches in Electricity, — Eighth Se- ries, By Michael Faraday, D,C.L.F,R.S.Fullerian Prof, Chem, Royal Institutio7i, Corr, Memh. Royal and Imp. Acadd. of Sciences^ Paris, Petersburgh, Florence, Copenhagen, Ber- lin, &)C. Sfc. [Continued from p. 348, and concluded.] f V. General Remarks 07i the active Voltaic Battery. lOS*. 'l^HEN the ordinary voltaic battery is brought into ^^ action, its very activity produces certain effects, which re-act upon it, and cause serious deterioration of its power. These render it an exceedingly inconstant instru- ment as to the quantity of effect which it is capable of pro- ducing. They are already, in part, known and understood ; but as their importance, and that of certain other coincident results, will be more evident by reference to the principles and experiments already stated and described, I have thought it would be useful, in this investigation of the voltaic pile, to notice them briefly here. 1035. When the battery is in action, it causes such sub- stances to be formed and arrayed in contact with the plates as very much weaken its power, or even tend to produce a counter current. They are considered by Sir Humphry Davy as sufficient to account for the phaenomena of Ritter's second- ary piles, and also for the effects observed by M. A. De la Rive with interposed platina plates *. 1036. I have already referred to this consequence (1003.), as capable, in some cases, of lowering the force of the current to one eighth or one tenth of what it was at the first moment, and have met with instances in which its interference was very great. In an experiment in which one voltaic pair and one interposed platina plate were used with dilute sulphuric acid in the cells (fig. 31.), the wires of communication were so ar- ranged, that the end of that marked 3 could be placed at pleasure upon paper moistened in the solution of iodide of potassium at x, or directly upon the platina plate there. If, after an interval during which the circuit had not been com- plete, the wire 3 were placed upon the paper, there was evi- dence of a current, decomposition ensued, and the galvano- meter was affected. If the wire 3 were made to touch the metal of jj, a comparatively strong sudden current was pro- duced, affecting the galvanometer, but lasting only for a mo- ment; the effect at the galvanometer ceased, and if the wire 3 were placed on the paper at x, no signs of decomposition occurred. On raising the wire 3, and breaking the circuit * Philosophical Transactions, 1826, p. 413. [or Phil. Mag. and Annals, N.S., vol. i. p. 193.— Edit.] Causes of dinmiished Activity of the Battery, 411 altogether for a while, the apparatus resumed fts first power, requiring, however, from five to ten minutes for this purpose; and then, as before, on making contact between 3 and p, there was again a momentary current, and immediately all the ef- fects apparently ceased. 1037. This effect I was ultimately able to refer to the state of the film of fluid in contact with the zinc plate in cell i. The acid of that film is instantly neutralized by the oxide formed ; the oxidation of the zinc cannot, of course, go on with the same facility as before; and the chemical action being thus inter- rupted, the voltaic action diminishes with it. The time of the rest was required for the diffusion of the liquid, and its re- placement by other acid. From the serious influence of this cause in experiments with single pairs of plates of different metals, in which I was at one time engaged, and the extreme care required to avoid it, I cannot help feeling a strong sus- picion that it interferes more frequently and extensively than experimenters are aware of, and therefore direct their atten- tion to it. 1038. In considering the effect in delicate experiments of this source of irregularity of action in the voltaic apparatus, it must be remembered that it is only that very small portion of matter which is directly in contact with the oxidizable metal which has to be considered with reference to the change of its nature; and this portion is not very readily displaced from its position upon the surface of the metal (582. 605.), especially if that metal be rough and irregular. In illustra- tion of this effect, I will quote a remarkable experiment. A burnished platina plate (569.) was put into hot strong sul- phuric acid for an instant only: it was then put into distilled water, moved about in it, taken out, and wiped dry: it was put into a second portion of distilled water, moved about in it, and again wiped : it was put into a third portion of distilled water, in which it was moved about for nearly eight seconds ; it was then, without wiping, put into a fourth portion of di- stilled water, where it was allowed to remain five minutes. The two latter portions of water were then tested for sul- phuric acid ; the third gave no sensible appearance of that substance, but the fourth gave indications which were not merely evident, but abundant, for the circumstances under which it had been introduced. The result sufficiently shows with what difficulty that portion of the substance which is in contact with the metal leaves it; and as the contact of the fluid formed against the plate in the voltaic circuit must be as intimate and as perfect as possible, it is easy to see how quickly and greatly it must vary from the general fluid in the 3 G2 412 Dr. Faraday's Experimental Researches in Electricity, cells, and how influential in diminishing the force of the bat- tery this effect must be. 1039. In the ordinary voltaic pile, the influence of this effect will occur in all variety of degrees. The extremities of a trough of twenty pairs of plates ot Wollaston's construction were connected with the volta-electrometer, fig. 11. (711.), of the Seventh Series of these Researches*, and after five minutes the number of bubbles of gas issuing from the extremity of the tube, in consequence of the decomposition of the water, [was] noted. Without moving the plates, the acid between the copper and zinc was agitated by the introduction of a feather. The bubbles were immediately evolved more rapidly, above twice the number being produced in the same portion of time as before. In this instance it is very evident that agitation by a feather must have been a very imperfect mode of restor- ing the acid in the cells against the plates towards its first equal condition ; and yet imperfect as the means were, they more than doubled the power of the battery. The first effect of a battery, which is known to be so superior to the action which the battery can sustain, is almost entirely due to the favourable condition of the acid in contact with the plates. 1 04-0. A second cause of diminution in the force of the voltaic battery, consequent upon its own action, is that extraordinary state of the surfaces of the metals (969.) which was first de- scribed, I believe, by Ritter -]-, to which he refers the powers of his secondary piles, and which has been so well experi- mented upon by Marianini, and also by A. De la Rive. If the apparatus, fig. 31. (1036.), be left in action for an hour or two, with the wire 3 in contact with the plate jp, so as to allow a free passage for the current, then, though the contact be broken for ten or twelve minutes, still, upon its renewal, only a feeble current will pass, not at all equal in force to what might be expected. Further, if P* and P^ be connected by a metal wire, a powerful momentary current will pass from P^ to P^ through the acid, and therefore in the reverse direc- tion to that produced by the action of the zinc in the arrange- ment; and after this has happened, the general current can pass through the whole of the system as at first, but by its passage again restores the plates P^ and P' into the former opposing condition. This, generally, is the fact described by Ritter, Marianini, and De la Rive. It has great opposing influence on the action of a pile, especially if the latter consist of but a small number of alternations, and has to pass its cur- rent through many interpositions. It varies with the solution [* Lond. and Edinb. Phil. Mag., 1834.— Edit.] t Journal de PhysiquCy Ivii. p. 349. Injurious Arrangements of the Voltaic Battery. 4<13 in which the interposed plates are immersed, with the inten- sity of the current, the strength of the pile, the time of action, and especially with accidental discharges of the plates by in- advertent contacts or reversions of the plates during experi- ments, and must be carefully watched in every endeavour to trace the source, strength and variations of the voltaic current. Its effect was avoided in the experiments already described (1036. &c.), by making contact between the plates P' and P^ before the effect dependent upon the state of the solution in contact with the zinc plate was observed, and by other pre- cautions. 1041. When an apparatus like fig. 26. (1017.) with several platina plates was used, being connected with a battery able to force a current through them, the power which they ac- quired, of producing a reverse current, was very considerable. 1042. Weak and exhausted charges should never be used at the same time with strong and fresh ones in the different cells of a trough, or the different troughs of a battery: the fluid in all the cells should be alike, else the plates in the weaker cells, in place of assisting, retard the passage of the electricity gene- rated in, and transmitted across, the stronger cells. Each zinc plate so circumstanced has to be assisted in decomposing power before the whole current can pass between it and the liquid. So that, if in a battery of fifty pairs of plates, ten of the cells contain a weaker charge than the others, it is as if ten decomposing plates were opposed to the transit of the current of forty pairs of generating plates (1031.)' Hence a serious loss of force, and hence the reason why, if the ten pairs of plates were removed, the remaining forty pairs would be much more powerful than the whole fifty. 1043. Five similar troughs, of ten pairs of plates each, w^ere prepared, four of them with a good uniform charge of acid, and the fifth with the partially neutralized acid of a used bat- tery. Being arranged in right order, and connected with a volta-electrometer (Til.)? the whole fifty pairs of plates yield- ed 1-1 cubic inch of oxygen and hydrogen in one minute; but on moving one of the connecting wires so that only the four well-charged troughs should be included in the circuit, they produced with the same volta-electrometer 8*4 cubical inches of gas in the same time. Nearly seven eighths of the power of the four troughs had been lost, therefore, by their associa- tion with the fifth trough. 1044. The same battery of fifty pairs of plates, after being thus used, was connected with a volta-electrometer (711.), so that by quickly shifting the wires of communication, the cur- rent of the whole of the battery, or of any portion of it, could 414 Dr. Faraday *s Experimeyital Researches in Electricity, be made to pass through the instrument for given portions of time in succession. The whole of the battery evolved 0*9 of a cubic inch of oxygen and hydrogen in half a minute; the forty plates evolved 4*6 cubic inches in the same time, the whole then evolved 1 cubic inch in the half minute; the ten weakly charged evolved 0*4 of a cubic inch in the time given : and finally the whole evolved 1*15 cubic inch in the standard time. The order of the observations was that given : the results sufficiently show the extremely injurious effect produced by the mixture of strong and weak charges in the same battery*. 1045. In the same manner associations oi strong and *meak pairs of plates should be carefully avoided. A pair of copper and platina plates arranged in accordance with a pair of zinc and platina plates in dilute sulphuric acid, were found to stop the action of the latter, or even of two pairs of the latter, as effectually almost as an interposed plate of platina (1011.), or as if the copper itself had been platina. It, in fact, became an interposed decomposing plate, and therefore a retarding instead of an assisting pair. 1046. The reversal^ by accident or otherwise, of the plates in a battery has an exceedingly injurious effect. It is not merely the counter action of the current which the reversed plates can produce, but their effect also in retarding even as indifferent plates, and requiring decomposition to be effected upon their surface, in accordance with the course of the cur- rent, before the latter can pass. They oppose the current, therefore, in the first place, as platina interposed plates would do (1011 — 101 S.); and to this they add a force of opposition as counter- voltaic plates. I find that, in a series of four pairs of zinc and platina plates in dilute sulphuric acid, if one pair be reversed, it very nearly neutralizes the power of the whole. 1047. There are many other causes of reaction, retarda- tion, and irregularity in the voltaic battery. Amongst them is the not unusual one of precipitation of copper upon the zinc in the cells, the injurious effect of which has before been ad- verted to (1006.). But their interest is not perhaps sufficient to justify any increase of the length of this paper, which is rather intended to be an investigation of the theory of the voltaic pile than a particular account of its practical applica- tion. liJote, — Many of the views and experiments in this Series of my Experimental Researches will be seen at once to be cor- •♦ The gradual increase in the action of the whole fifty pairs of plates was due to ihe elevation of temperature in the weakly charged trough by the passage of the current, in consequence of which the exciting energies of the fluid within were increased. Mr. Addams on the Repulsive Action of Heat. 415 rections and extensions of the theory of electro-chemical de- composition, given in the Fifth and Seventh Series of these Researches. The expressions I would now alter are those which relate to the independence of the evolved elements of the poles or electrodes, and the reference of their evolution to powers entirely internal (524. 537. 661. )• The present paper fully shows my present views; and I would refer to para- graphs 891. 904. 910. 917. 918. 947. 963. 1007. 1031. &c., as stating what they are. I hope this note will be considered as sufficient in the way of correction at present; for I would rather defer revising the whole theory of electro-chemical de- composition until I can obtain clearer views of the way in which the power under consideration can appear at one time as associated with particles giving them their chemical attrac- tion, and at another as free electricity (493. 957.)' — M. F. Royal Institution, March 31, 1834. LXV. Notice of some Experiments "uohich show a repulsive Ac» lion between heated Surfaces and certain pulverulent Bodies. By R. Addams, Esq., Lecturer on Chemistry and Natural Philosophy*. T^HAT caloric possesses a repellent force is assumed from -*- the effects it produces upon matter in general : but there are those who do not allow that we have any unequivocal evidence of calorific repulsion between independent bodies, such, for example, as two separate masses of heated iron ; in- deed, the question whether caloric does not act repulsively at sensible distances, has recently been made the subject of experimental investigation by the Rev. Professor Powellf, who, in the Philosophical Transactions for the last year, has given an account of an elegant and refined mode of testing the repulsion between two heated lenticular masses of glass. The following description of some experiments which seem to bear upon the question may not, therefore, be unacceptable to those who are interested in this branch of inquiry. Exp. 1. A small quantity of silica (prepared by precipitation from its alkaline solution) was heated upon a platinum cap- sule : when the heat — that from a spirit-lamp — had acted for a second or two, the powder moved, by the least mo- tion of the capsule, as if it were floating upon a liquid, having a mobility almost equal to that of mercury. The fric- * Communicated by the Author. t Lond. and Edinb. Phil. Mag., vol. vi. p. 58. 416 Mr. Addams on the Repulsive Actioji of Heat. tion between the metal and silica was so trifling that the latter would often remain stationary, whilst the former slid beneath it ; and when the capsule was moved, by the hand, circularly in one direction, the powder would revolve the contrary way. The effect ceases almost instantly by a removal from the lamp, and is renewed as often as it is reheated. Whilst subjected to the flame of the lamp, if touched with a cold body, as a metallic wire or glass rod, it would sometimes lose its peculiar freedom to glide about, and then rest upon the platinum vessel slug- gish and immoveable otherwise than with the vessel itself. Exp. 2. Supposing it possible that moisture might inter- fere, I introduced another portion of silica into a glass flask, mounted with a stop- cock, and heated it to a temperature of from 300° to 500°, in which state it was kept for a week with the valve closed. After the first action of the heat to expel a part of the air, it still continued to exhibit the same phaeno- menon as before in the open vessel. The air was additionally rarified by an air-pump, but with no alteration in the beha- vour of the powder. Exp. 3. Magnesia, peroxide of copper, sesquioxide of lead, peroxide of cobalt, oxide of nickel, peroxide of manganese, and smalt, were successively heated as in Exp. 1, and with correspondent results. On the other hand, oxide of chromium, litharge, and alu- mina afforded little or no evidence of such peculiarity. Remembering Dr. Faraday's experiment " on the electric powers of oxalate of lime*," I subjected that compound to a similar trial ; and obtained evidence of the same kind of mo- tion as before (1.), yet in a less degree than with silica and the substances named in No. 3. from magnesia to smalt in- clusive. The powders were more or less in an electric state, but this (the electricity,) I regard as an accompaniment, and not as the cause of the free motion of the powders upon the metal ; for touching the metal with good conductors of electricity made no alteration save that which could fairly be assigned to the cooling effect upon the platinum or glass capsules, both having been employed. Also by insulating the platinum no difference was noticed. In Dr. Faraday's experiment before referred to, the ox- alate of lime was electrified, positively, by stirring it with a rod or spatula, whereas the diminished friction or contact be- tween the bodies concerned in the experiments now de- scribed took place without stirring or previous agitation. * Journal of the Royal Institution, vol. xix. p. 338. Prof. Graham on Water as a Constituent of Salts. 417 The quantities of the powders which I have hitherto em- ployed have been too small, (not exceeding 30 or 40 grains,) to decide upon their electrical states in a satisfactory manner. Before I conclude the present communication, I will ad- vert to a simple experiment, which is familiar to many, I have no doubt, and which bears upon the subject under considera- tion. Thus : take up a small portion of tallow at the end of a wire; hold the latter inclined to the horizon and with the hand uppermost; thrust the tallow into the flame of a candle, and it will be seen to react from the heat and run up the wire, in a melted state, to the distance of an inch or more. Professor Stevelly alluded to this experiment in reference to the repul- sive agency of heat, at the meeting of the British Association in Edinburgh. Kensington, January 6, 1 835. LXVI. On Water as a Constituent of Salts, In the Case ofSul- phates. By Thomas Graham, F.R.S.E., Andersonian Professor of Chemistry and Vice-President of the Philoso^ phical Society of Glasgow. [Continued from p. 334, and concluded.] Sulphate of Zinc with Sulphate of Soda : Zn'S(NaS) + H\ Sul- phate of Zinc and Soda. T^HIS salt, I believe, has not hitherto been described. I -■- failed in attempting to form it, by dissolving together sulphate of zinc and sulphate of soda in atomic proportions : the salts uniformly crystallized apart, either in cold or in warm weather. Each of the salts was also added in excess to the other, but with no better effect. It appears, then, that sulphate of soda does not displace the saline water of sulphate of zinc, so easily as sulphate of potash does. But the desired salt was obtained by a process of double decomposition, suggested from consideration of the relations of the sulphates. Solu- tions of bisulphate of soda, and of sulphate of zinc, were mixed together in atomic proportions, from which the sul- phate of zinc and soda separated in a gradual manner in the course of a day or two, leaving sulphuric acid in solution. Sulphate of zinc with saline "j f Sulphate of zinc with sulphate of water, I • ijJ soda. Sulphate of water with sul- j ^ j Sulphate of water with saline phate of soda, J I water. This salt is deposited in distinct tabular crystals, of a pecu- Third Series. Vol. 6. No. 36. June 1 835. 3 H 418 Prof. Graham 07i Water as a Constituent of Salts. liar form, which are often associated in tufts ; and is best ob- tained by evaporating the mixed solutions over sulphuric acid without heat. It caimot be redissolved in pure water, without undergoing decomposition, which accounts for the impossibi- lity of forming it by the direct process. The crystals contain four atoms of water, and are about as deliquescent as nitrate of soda, in a damp atmosphere. The anhydrous salt under- goes fusion, like all the other double sulphates, at an incipient red heat, without the evolution of acid fumes. The fused salt solidifies, on cooling, into a white and opake mass. Sulphate of Copper with Saline Water: CuiSH-f-H*. Sulphate of Copper. The common blue rhomboidal crystals of sulphate of cop- per contain five atoms of water, four of which are readily ex- pelled, by drying the salt in air at 212°; by which treatment the salt loses its blue colour, and becomes white, with a dirty shade of green. The sulphate of copper with one atom of water was also obtained in a crystallized state by Dr. Thom- son, and called by him green sulphate of copper. Dried over sulphuric acid in vacuo for seven days, when it had ceased to lose, at a temperature between (S5° and 74°, the common hy- drated salt retained 21-67 parts water to 100 anhydrous salt, which is somewhat under two atomic proportions of water, namely 22*57 parts. At a temperature between 430° and 470°, the sulphate of copper loses its fifth, or saline, atom of water, and is found in the state of a powder, which is white without any shade of colour. When a few drops of water are thrown upon anhydrous sulphate of copper, it slakes and be- comes blue, and so much heat is evolved as to occasion the ebullition of the water. In one case the temperature was ob- served to rise to 276°. This arises from the resumption of saline water by the salt. Sulphate of Copper with Sulphate of Potash : CuS(KS) + H«. Sulphate of Copper and Potash, This salt may be formed by mixing sulphate of copper with either sulphate or bisulphate of potash, in atomic proportions. Dried in the open air, it loses six atoms water, and becomes quite anhydrous at a temperature not exceeding 270° Fahr. The following Table of the composition of this hydrated salt in different circumstances, illustrates three facts, — that the salt has a disposition to retain two atoms of water when dried at 212° in open air, — that a greater portion of water of crystal- lization is withdrawn from the salt by drying it over sulphuric Prof. Graham on Water as a Constituent of Salts, 419 acid in vacuo, without artificial heat, than by drying it at 212° under the atmospheric pressure, and that the mechanical wa- ter retained by the crystals of this salt may exceed 3 per cent, of their weight. Anhy- drous Salt. "A "J Dried on water-bath at 212°, for three days, or till ceased to lose weight ... Dried on nitre-bath at 238°, 1 for three days j Dried in vacuo over sulphuric" acid for seven days, or till it ceased to lose weight; therm, from 65° to 74^° ..._ Crystals pounded, and slightly") dried at 80°, so as not to (^ injure the lustre of an en- f tire crystal J Same crystals not deprived") of mechanical water by the ^ above treatment J Composition of sulphate of"^ copper and potash with two )> atoms of water (by theory) J Composition of do. with six 1 atoms of water (by theory) j 19-6 22-06 22-97 13-94' 23-79 Water. 2-21 2-37 1-61 3-4 8-64 Anhy- drous Salt. 100 100 100 100 100 100 100 Water. 11-27 10-74 7-09 32*25 36*22 10-77 32-33 I have confirmed the observation of Berzelius, that a c(m- centrated solution of this salt, when boiled, deposits an inso- luble subsalt, containing sulphate of potash, but which is de- composed by washing, and cannot be had in a proper state for analysis. But the crystals of the double salt are quite so- luble after being heated to 212°, so that they do not undergo the same change as their solution does at that temperature. This double salt retains its blue colour after being fused at a red heat and cooled, and does not become white like the sulphate of copper. Indeed it appears, that, to be coloured, the salts of the oxide of copper require the addition of some other constituent, such as saline water, sulphate of potash, or ammonia. Hence, if the absolute sulphate of copper could be obtained in a crystallized state, it would be a colourless salt. 3H2 4-20 Prof. Graham on Watet' as a Constituent of Salts. Sulphate of Copper with Sulphate of Soda : CuS(NaS) + H^ Sulphate of Copper and Soda, Like the other double salts of sulphate of soda, this salt cannot be formed directly, being decomposed by water. Even when it is attempted to form it by double decomposition from the bisulphate of soda, in general a large quantity of sulphate of soda and of sulphate of copper are separately deposited before the double salt appears. It is then deposited in a crust, con- sisting of small but distinct crystals, which are slightly deli- quescent, and appear to contain two proportions of water. This salt is easily made anhydrous, and thereafter fuses at an incipient red heat without loss of acid, and remains of a blue colour when cool. The fused salt does not split into thin scales in the progress of cooling, as the corresponding sul- phate of copper and potash does. Sulphate of Manganese with Saline Water: MnSH + H*. Sul- phate of Manganese, The water in this salt was found to be reduced from five atomic proportions to little more than one, by drying the cry- stals in open air at 238°, while one entire atomic proportion was retained at 410°. Flesh-coloured crystals, dried in vacuo in warm summer weather, without artificial heat, lost some- what more than three proportions of water. Anhy- Anhy- drous Water. drous Water. Salt. Salt. 60-06 Flesh-coloured crystals of salt 28-42 17-07 100 Do. dried at 238° 21-53 2-92 100 13-05 A portion of last, afterwards^ dried for one hour between )- 9-54 1-12 100 11-74 380° and 410° J A portion of same, dried for"^ one hour between 415° and V 10-90 0-56 100 5-14 468° ^ Crystals dried for nine days" in vacuo over sulphuric . acid, therm. 64° to 72°, but ^ 8-62 11 100 20-88 had lost nothing the last two days _ Composition of sulphate of^ manganese with one atom > ... ... 10 11-88 of water (by theorv) J Composition of do. with five ) atoms of water J ... ... 100 59-4 Prof. Graham on Water as a Constituent of Salts. 421 A crystalline crust of sulphate of manganese, deposited from a warm solution, was found to contain three atoms of water. It is likewise known to be deposited from a boiling solution with only one atom of water, namely, the saline atom. We have, therefore, sulphates of this class with no water of cry- stallization, and with two, four, and six atoms. The sulphate of manganese and potash did not crystallize on mixing the solutions of its constituents. The sulphate of manganese and soda was obtained in analogous circumstances with the sulphate of copper and soda, but was not examined. Sulphate of Iron with Saline Water: FeSH+H«. Sulphate of Iron. Of the seven atomic proportions of water which the crystals contain, 5* 48 proportions were lost in vacuo over sulphuric acid; and six proportions at 238°, and probably at lower tem- peratures. The saline atom of water is retained by this salt at so high a temperature as 535°. But the salt can be made perfectly anhydrous, with proper caution, without appreciable loss of acid. Sulphate of Iron with Sulphate of Potash : FeS(KS)-f H^ Sulphate of Iron and Potash. A specimen of this salt was made anhydrous by a sandbath heat, which was found not to affect the saline atom of water of the preceding compound. Sulphate of nickel was found to correspond closely with sulphate of iron in the temperatures at which it lost its water of crystallization, and also its saline water. And in the case of both of the compounds of these salts with sulphate of pot- ash, a considerably higher temperature was required to ren- der them perfectly anhydrous, than in the case of the cor- responding double salt of zinc. Sulphate of Magnesia with Saline Water : MgSH -h H^ Sul- phate of Magnesia, One atom of water is retained by sulphate of magnesia at 460°, but the other six are not entirely expelled under 270° in open air. Indeed this sulphate is remarkable for a disposi- tion to retain two atoms of water, in which respect it resembles the sulphate of lime. Dried at 212° in open air, the crystals of sulphate of magnesia were found in several experiments to retain somewhat more than two atomic proportions of water. When dried at the same temperature i?i vacuo over sulphuric acid, the water was reduced to two proportions. Crystals 422 Prof. Graham on Water as a Conslituent of Salts. placed over sulphuric acid ifi vacuo, without heat, were found to retain only two and a quarter atomic proportions of water. Anhy- drous Salt. Water Anhy- drous Salt. Water. Crystallized salt, dried i?n vacuo at 70° for six days, or > till it ceased to lose J Do. i?i vacuo at 212"^ 12-34 21-8 4-9 4-13 6-24 0-74 100 100 100 100 33-46 28-62 15-1 14-81 Do. heated between 410° andl 460° for one hour, being )> previously dried at 238° ...J Relative composition of thel anhydrous salt with one )> atom of water (by theory) J The sulphate of magnesia and ammonia lost its six atoms of water of crystallization and became anhydrous, when exposed to a temperature not exceeding 270°, for one hour, having previously been dried at 212°. It retained of course the atom of water which is essential to the ammoniacal salts. A some- what higher temperature was required to deprive the sulphate of magnesia and potash of its whole water of crystallization. Hydrated Sulphate of Lime : CaS H + H. The only crystalline hydrate of sulphate of lime, which is known, contains two atoms of water. It occurs native in [the form of] gypsum and selenite. Pounded selenite loses little or nothing in the open air at 212°. Water begins to escape at a temperature not much higher, but is not completely expelled by any degree of heat under 270°. That hydrated sulphate of lime may contain an atom of saline water, is indicated by the existence of a double saltof sulphate of lime with sulphate of soda, constituting the mineral Glauberite. I succeeded in ob- taining a definite compound of sulphate of lime with one atom of water, by drying pounded selenite, at 212°, in vacuo over sulphuric acid*. The salt which had been so dried at 212° did not form a coherent mass, like stucco, when made into a paste with water. The affinity of sulphate of lime for the sa- line atom of water appears to be feeble, as the salt can be made quite anhydrous under 300° ; and consequently the sul- * It has subsequently been observed, that the water is reduced under one atomic proportion, by a protracted exposure to the same tempera- ture. Prof. Graham on Water as a Constituent of Salts, 423 phate of lime has much less disposition to form double salts than the sulphates of magnesia, zinc, &c. Anhy- drous Salt. Water. Anhy- drous Salt. Water. Selenite, dried for ten days in 1 open air at 212° \ J Do. dried in vacuo at 212° Sulphate of lime with one\ atom of water (by theory) j Do. with two atoms of wateri (by theory) J 17-07 17-61 • •• • •• 4-27 3-04 100 100 100 100 25-01 14-72 13-13 26-26 In drying gypsum, to make plaster of Paris, a third or a fourth of the water of the salt is allowed to remain, by which it sels more strongly. But the salt may be made quite anhy- drous, I find, and yet retain the power of recombining with two atoms of water, if dried at a temperature not exceeding 270° Fahr. ; although the hydrate which results on slaking in the last case is rather pulverulent. When gypsum has been dried at a higher temperature, as at 300° or 400° Fahr., it refuses entirely to combine with water, and is technically called burnt stucco. The anhydrous sulphate of lime which occurs in nature exhibits the same indifference to water. In anhydrite we have, I believe, the true or absolute sulphate of lime in a crystallized state. The body which results from ex- posing hydrated sulphate of lime to 270°, although composed of nothing but sulphuric acid and lime, should be viewed as the debris of the hydrated sulphate of lime, and not confounded with the absolute sulphate of lime, which last has no disposi- tion to combine with water. The first, which we may call " anhydrous gypsum," is an imperfect body. We know sul- phate of lime in four states, which may be expressed symbo- lically as follows: Gypsum CaSH + H Gypsum dried at 212° Ca'SH Anhydrous gypsum (dried at 270°) CaS — Anhydrite CaS Here we distinguish the imperfect body, anhydrous gypsum, from anhydrite, by placing the minus sign after the former. In the same manner, concentrated sulphuric acid, or oil of vitriol, may be represented by HS— ; anhydrous sulphate of 424 Notice of the Arrival of Birds of Passage at Carlisle, magnesia, sulphate of zinc, &c. by MgS — , ZnS— , &c. ; the absolute sulphates of water, magnesia, zinc, &c., HS, MgS, ZnS, &c., being unknown to us. The view which is given in this paper of the constitution of the sulphates, must not be hastily generalized and applied to other classes of salts. From investigations not yet completed, I am satisfied that each class of salts has its peculiarities, which must be studied before the law of the class can be laid down. LXVII. Notice of the Arrival of Thsoenty-six of the Summer Birds of Passage in the Neighbourhood of Carlisle^ durifig the Spring qfl824f, to which are added a few Observations on some of the scarcer Birds that have been obtained in the same Vicinity from the \Oth of November 1833 to the lOth of No- vember 1834. By A Correspondent.* No. English Specific Names. Latin Generic and Specific Names. When first observed. No. I 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 Quail Swallow House Martin Sand Martin Swift Goatsucker Pied Flycatcher Spotted Flycatcher Ring Ouzel Wheatear Whinchat Redstart Grasshopper Warbler... Sedge Warbler Greater Petty chaps ... Wood Wren. Blackcap Whitethroat Yellow Wren Yellow Wagtail Field Lark, or Titling... Cuckoo Wryneck Corncrake,or Land-Rail Dottrel Common Tern Coturnix vulgaris. Hirundo rustica . . urbica ... nparia Cypselus A pus, Caprimulgus europaeus Muscicapa Atricapilla Grisola. . . . Turdus torquatus. Saxicola CEnanthe , Rubetra . Sylvia Phcenicurus Curruca Locustella, salicaria . . , hortensis . - Sibilatrix.... - Atricapilla . . Sylvia . Regulus Trochilus . . . Motacilla flava Anthus trivialis Cuculus canorus Yunx Torquilla Ortygometra Crex ... . Charadrius Morinellus Sterna Hirundo April May April May April May April May 20 4 28 4 27 3 25 3 5 8 15 17 7 30 1 3 14 30 16 5 18 17 15 10 11 9 6 35 36 36 37 38 41 42 49 53 54 57 58 59 62 63 64 66 70 75 78 121 125 129 164 235 lObs. — The figures contained in the column on the right in the above * Communicated by the Author. Notice of the Arrival of Birds of Passage at Carlisle, 425 Q^uaiL — Two specimens of this bird were killed in this di- strict during the winter months of 1833-4, namely, one near Druinbrugh on the 18th of December 1833, the other in the vicinity of Wigton on the 6th of November 1834; both were males. 79. Crossbill [Loxia curvirostra). — A small flock of Cross- bills were accidentally observed in a fir-plantation not far from the village of Castle Carrock on the 26th of February, eight of wliich were obtained. This bird is of very rare occurrence in this neighbourhood, yet we have some reason to believe that a few visit the hilly districts in this county almost an- nually, at least more frequently than is generally supposed. 138. Dusky Sandpiper or Spotted Snipe {Totanusfusais) .'■^ A young bird of this species was occasionally seen on Rock- cliff Marsh about the middle of August; it, however, escaped, although pursued for several days. 140. Green Sandpiper (Tota?ius ochropiis), — Two Green Sandpipers were shot in the month of August; the first on the 7th, on the banks of the river Esk, near Floris town ; the second on the 1 0th, a short distance from the river Petri], in the vicinity of Newbiggin Hall : one or two others were seen. 152. Pygmy Curlew {Tringa stibarquata), — A pretty large flock of Pygmy Curlews frequented the Rockcliff Marsh during the latter end of September and the beginning of October. All the specimens killed that came under our observation were young birds of the year. A few years ago this species was considered one of the rarest British visitants, but latterly it has been annually met with in various parts of England, as well as in Ireland. 159. Common Turnstone {Strepsilas Interpres). — On the 13th of August six Turnstones were seen on the hilly moors in the parish of Bewcastle, a very considerable distance from the coast. 161. Grey Plover (Squalarola cinerea), — Grey Plovers in pretty considerable numbers visited the coast in this vicinity during the latter end of September and the beginning of Oc- tober. The few that were obtained were all young birds. On referring to the few remarks we made on this species in our communication for the year 1830, it will be seen that the Table, as well as those affixed to the species not included in it, refer to the numbers in Fleming's History of British Animals, which ^ye have inserted, in order that any reader who may wish to have a description or to see the various synonyms of any of the birds alluded to in this paper may find the species at once, should he possess or have an opportunity of consulting tnat very useful publication.] Third Series. Vol.6. No. 36. Ju?ie 1835. 3 I 426 Notice of the Arrival of Birds of Passage at Carlisle. Grey Plover is only occasionally met with in this part of the couBty *. 180. Long-tailed Duck [Clangula vulgaris), — The only spe- cimen of this species that has been detected in this vicinity, to the best of our knowledge, was killed about the 1st of Novem- ber. It was a very young bird, but most fortunately proved to be a male, so that we had the gratification of examining the very singular trachea of this species, which Montagu has figured with great accuracy in the Supplement to the Orni- thological Dictionary. 204. Razor Bill (Alca Torda). — A specimen of this bird was killed on the 1st of January, in a rather singular locality, namely, on the moors in the parish of Bewcastle, at no great distance from the situation where the Turnstones above al- luded to were seen. This bird was, no doubt, on its passage either to or from the western coast. 206. Crested Grebe {Podiceps cristatus), — An old male of this species was obtained on Brugh Marsh on the 3rd of October. Although young birds are now and then met with, this is the only instance that has come to our knowledge of the capture of an adult in this neighbourhood. 213. Red-throated Diver {Colymhus septentrionalis) .-^ An adult Red-throated Diver, in nearly full summer plumage, was caught in a stake-net on the coast, on the 1st of May. Not- withstanding the period of the year, the bird was very much in moult. 214. Foolish Guillemot (Uria Troile), — No less than three specimens of this bird have been captured, at no great distance from Carlisle, during the present year. The first in the be- ginning of January, in the river Edin near Linstock ; the se- cond on RockclifF Marsh, on the 8th of April; the third was caught alive on Brugh Marsh, on the 10th of August. This species is very seldom seen in the immediate vicinity of Car- lisle. 216. Little Auk or Common Rotche (Mergulus melanoleucos), — A female of this species was found dead on the coast, a short distance from Allonby, on the 6th of December ; another was shot on the river Eden near Amathwaite Castle, in the latter end of January 1794: the only two specimens of this bird which have been detected in this district that we are at present aware off. 234. Roseate Tern {Sterna Dougallii). — A fine male of this beautiful Tern, beyond all doubt the most elegant of the Bri- * Phil. Mag. and Annals, N.S., vol. viii. p. 448. t Hutchinson's History of Cumberland, vol. i. p. 20. Optical Effects of the Magneto-electrical Machine, 427 tish Sternidae, was accidentally shot near Brugh Marsh Point, on the 26th of July. For the last five years we have diligently searched after this bird in this quarter without success, and we have little or no doubt that the above was an accidental straggler on its passage to the south. A few Meteorological Remarks on the Spring, Summer, and Autumn of 1834-, at Carlisle. The weather during the greater part of the month of March, especially from the 10th to theliTth, was remarkably fine and mild ; on the 29th, however, there were several smart hail- showers, and on the 31st the western mountains were com- pletely covered with snow. Nearly the whole of April was exceedingly chilly and cold ; early on the morning of the 29th we had a slight fall of snow, which, however, almost imme- diately disappeared, and after the 30th it became fine and seasonable. The summer and autumn, generally speaking, were fine, yet somewhat showery, particularly during the latter end of August and the greater part of September, which slightly in- jured the wheat and other crops in many parts of this district. From the end of September to the 10th of November, the weather here was almost unprecedentedly mild and dry. Carlisle, Nov. 10, 1834. LXVIII. On certain Optical Effects of the Magnetic-Electrical Machine, and on an Apparatus for decomposing Water hy its means. By Mr, Edward M. Clarke. To the Editors of the Philosophical Magazine and Journal, Gentlemen, T^RYING the effect of the magnetic electrical machine on * the optic nerves, I observed the following curious phae- nomenon. On grasping in one hand (which had been previously wetted with vinegar) one of the conductors, insulating the other hand with a glove, and slightly pressing the extremity of the other conductor to the wetted forehead, the mouth was af- fected with a metallic taste, similar to that produced when silver and zinc are brought into contact with the tongue, but much stronger. On closing my eyes I observed, where the conductor touched the forehead, a luminous disk, the light of which emanated in waves from a bright spot in the centre. The luminous disk was bounded by a strongly marked black circle, outside of which was more light, similar to that of the 3l 2 428 Magneto-electrical Decomposition of Water, disk, but of less brilliancy. On communicating this to Dr. Faraday, he kindly suggested the trying the effect of a piece of wetted paper placed between the forehead and the con- ductor : the result was, the figure was better defined and more vivid. He further recommended the trial of a metallic disk, point, and line, successively, instead of the hollow cylindrical conductor as before; but no apparent change was visible in its effects. The arrangements of the terminating wires of the conductors is the same as already described in my former paper, p. 169. Care must be taken that the wires of the conductors are not removed from the mercury in which they are im- mersed, otherwise (as I have experienced) a violent secondary shock will be felt. The apparatus heretofore used for the decomposition of water being defective, in so far that the connexions were im- perfectly formed, did not thoroughly answer the purpose in- tended for the magnetic electrical machine. I send you a sketch of one constructed by myself, which answersy?///?/ the purposes for which it was intended, and has given satisfaction to all who have obtained them form me. Explanation of the Figure. A. A hard wood cup. B B. Two copper wires, havitig two pla- tinum wires, C C, Soldered to their extremities. D. A piece of glass tube cemented into A. E. A cork fitting loosely into D. F F. Two glass tubes closed at one end and fitted tightly into E. Introduce B B into the connecting holes of the magnetic electrical machine, and move E F F from D; pour dilute sulphuric acid into D, so as to cover C C ; fill the tubes F F also, and place them as before. 39, Charles street, Parliament street, Feb. 14, 1835. Edwaiid M. Clarke. I I '^^ A I MeridiKD 1 [ 429 ] LXIX. Trigonometrical Height of Inglehorough above the Level of the Sea, Part II. ^j/ John Nixon, £55'. [Continued from p. 261, and concluded.] Of the Vertical Angles, ^HE horizon sector was furnished with new arcs and veN niers (the former in February 1827j and the latter in January 1832,) divided by the best engine in London, yet de- cidedly inferior in accuracy to the original graduations by Allan. Formerly the bubble of each cross level was adjusted to its mark when its arch stood parallel to a plumb line sus- pended near it, but latterly the adjustment has been effected hi a superior manner. A block of wood 8j inches high, 6 long, and 2j thick, planed with its ends and sides perpen- dicular to its base, was mounted with a spirit-level, by which the base (by the process of reversing) could be set truly level. In this state, either arc when placed in exact contact with that end of the block in which recesses had been made for the protruding vernier, &c. would be vertical. Supposing the inclination of the arcs to be even 1°, an altitude of 2400 feet would be measured only 4 inches in excess, or in the propor- tion of the secant of the angle of inclination to radius. In making bisections of pale, dim, or very distant objects, a dot* of about the same diameter as that of the vertical wire (spider's line), and adhering to one side of it a few minutes above the middle of its height, was successfully made use of up to 1832, when the filament mentioned in Lond. and Edinb. Phil. Mag., at page 166 of volume iv., was substituted. When the object was so near or dark that die dot or filament could not be seen distinctly against it, recourse was had to the horizontal wire, which was pointed in the first instance a little too high, and then gradually lowered (by moving a light weight placed within the stand of the sector in the direction of the object,) until the lower edge of the wire and the base of the signal, &c. seemed (from the inflection of light?) suddenly to commence running into each other. Zenith distances thus measured — as the second observation, with the telescope inverted, is made with the opposite edge of the wire and will be equally in defect with the preceding one — require in strictness a minute correc- * The substitution of the dot for the horizontal wire arose from the im- possibility of measuring the depression of the horizon of the sea with the latter. [It may be useful to some of our readers to refer in this place to the substitution of a dot for cross wires made by Mr. Gardner, in the tri- gonometrical operations for determining the difference of longitude be- tween Paris and Greenwich, as stated by Capt. Kater in the Philosophical Transactions for 1828, p. 194 — 5, and considered by him to be a very im- portant improvement in the theodolite. — Edit.] 430 Mr. J. Nixon on the Trigonometrical Height tion additive for the semidiameter of the wire. As the arcs are not fixed exactly parallel to each other, the dot does not make precisely half a revolution downwards on inverting the tele- scope, and therefore cannot come to the previous perpendi- cular distance from the axis of the cylindrical telescope by a Quantity (too trivial, however, to be regarded,) equal to thi^ istance multiplied by the versed sine of the deviation of pa- rallelism of the arcs. It may be remarked also that when the cross wires are properly adjusted, the perpendicular one, from a defect in the stop, cannot be set quite parallel to either arc. This was first noticed on observing the dip of the sea, the horizontal wire being slightly inclined to the edge of the sea when either arc was vertical; but the deviation is not of a na- ture to vitiate the measurements. The reversing point* of neither of the great levels, but particularly of that marked G, proved so constant as heretofore; the seasoning which the levels had gradually acquired from repeated shocks in travel- ling, and by exposure to extremes of temperature, having been disturbed by dismounting them on commencing the survey and by frequent alteration of the adjustments, never in the course of any campaign, but during the intervening winters. As the fluctuation must have taken place chiefly on trans- porting the sector from one station to another rather than at the time of observation, the angles cannot have been materially affected in consecjuence. A register of the reversing points for each level is subjoined in a notef. Generally the sector * That degree of the scale at which the middle of the bubble stands when the axis of the cylindrical tube of the telescope lies parallel to the horizon. t Dates. "August 1829.< September October 1830. <^ U n Level G Level L No. of Obser- o o vations. 20. .... 74-6 .... 71-2 . .. 2 21. .... 73-3 .... 69-9 .... 2 22. .... 75-2 .... 72-5 .... 3 25. .... 77-0 .... 730 .... 2 28. .... 77-9 .... 73 2 .. . 1 3. .... 790 .... 70-3 .... 2 14. .... 78-8 .... 71-5 .... 1 15. .... 77-5 .... 71-8 .... 2 16. .... 74-2 .... 70-5 .... 2 1. .... 78-1 .... 70-2 .... 2 2. .... 79-7 .... 72-8 .... 3 4. .... 79-3 .... 71-7 .... 2 14. .... 79-1 .... 707 .... 4 21. .... 77-7 .... 71-3 .... 2 2. .... 80-0 .... 720 .... 2 25. .... 73-1 .... 726 .... 6 27. .... 72-2 .... 68-3 .... 3 15. .... 75-8 .... 700 .... 2 18. .... 76-4 .... 69-5 .... I November 'July 1832..^ September 15 (1° of the scale is about 2".) The sector was supported either by solid masonry or bedded rock. of Inglehorough above the Level of the Sea, 431 was supported by a firm pile of stones surmounted by a level flag, but in calm weather it was occasionally placed upon a large circular board, slightly concave at the upper surface, which was screwed firmly by its brass centre to the staff of the theodolite set up in the secure manner already de- cribed. As the atmospherical refraction is generally fluctuating, the best method of obtaining its mean value correctly from the reciprocal observations and depressions, will be to class the observations at the several stations according to their dates rather than by the mean of the whole series. The following list, constructed on this plan from sixty- four observations made on eighteen different days in 1829, 1830 and 1832, exhibits a mean refraction of about ^ of the contained arc. From this ratio the deviation of any day's observations (which is given in the last column,) is generally not only inconsiderable, but occurs in small arcs, where its effect on the differences of level becomes unimportant. With regard to the few striking exceptions, the one at Farleton Knot, marked K, was derived from a hasty measurement, on one arc only, of the elevation of Ingleborough as it was rapidly becoming obscured by mist. Those at Hest Wall originate, no doubt, in that horary varia- tion of the refraction occurring in low situations on calm bright days, which rendered so uncertam the measurement of the height of the tide. All the observations at Clougha, marked C, with the exception of the three first made — those of Ingleborough,— concur irt giving a refraction in excess, which may, perhaps, be accounted for by the wind, which was scarcely sensible at first, soon after blowing a strong gale* from the north-west, the quarter fronting the steep and lofty acclivity on which the pikes stand, and occasioning a con- densation of that portion of air through which the rays from the several signals would finally pass. All the angles, but in particular the concluding one, that of the Breakwater pole, were uncertain to a few seconds, from the tremulous motion of the pile supporting the sector, which had been constructed, very improperly, partly of sods. The letters in the list refer to the' dates given in the register of the observations. * The strong breeze off the bay of Morecambe, which had blown at Hest Bank all the morning, subsided about the time the gale sprung up at Clougha. 432 Mr. J. Nixon on the Triftonometrical Height Observed Refractions, Deviation Stations Arc. Refr. from Mean. Between Farleton Knot (L) and Hutton-RoofMoor fllestWall (0) (U) 1'40" 2 39 -2"-5 -8'' + 117 + 2-5 Warton Crag (F)- \ do. (V) 2 39 15-3 + 6 L do. (W) 2 39 153 + 6 Warton Crag (G) - / Hutton-RoofMoor \ do. (O) (P) 4 16 4 16 16-0 14-8 + 1-5 0 Farleton Knot (K) - Warton Crag CF) 4 49 18-5 + 2 Break waterPole(R) — r Clougha Pike do. (A) (C) 5 50 5 50 160 32-8 - 4 + 13 BreakwaterPole(R) — f Hutton-RoofMoor (0) \ do. (P) 7 26 7 26 27-5 310 + 2 + 5-5 Warton Crag (F)- 1 Clougha Pike (A) (C) 7 42 7 42 187 350 - 8 + 8-5 fHestWall (U) 8 23 167 —12 Farleton Knot (K) - < do. (V) 8 23 250 _ 3-5 L do. (W) 8 23 26-3 _ 2-5 CloughaPike (C)- Hutton-RoofMoor • (0) 9 42 383 + 5 Ingleborough (T)- f do. i do. (P) (Q) 10 5 10 5 37-5 41-0 + 3 4-6-5 "Farleton Knot (J) 11 8 39-5 + 1-5 do. (KJ 11 8 30-3 -8 Ingleborough (S)- <( do. iK 11 8 37-5 ^1 1 do. (M) 11 8 36-5 —1.5 L do. (N) 11 8 36-5 -1.5 Clougha Pike (C)- / do. \ do. (K) 11 9 11 9 35-4 37-2 -30 -1.0 Ingleborough (S) 1 Clougha Pike Sum (A) 13 22 44-5 -1-5 and (T) (C^ 13 22 + 40-0 -1-6 ... 3^ 44' 37" 12' 58" Mean refracti an of the whole f _-'^. ■ 1 = T^rr- : sav 1 Trigonometrical Differences of Level. Explanation, — The angles of elevation {El.) and depression (Z)/7.) are given corrected for the cylindrical error of the in- strument ( = 20"). At every station the height of the eye above the point there selected for bisection is stated, and from these data the differences of level are computed with a constant re- fraction of ^i^ ; but when any other point has been bisected, its height above ( + )or below ( — ), the standard datum, is given within brackets. The distances prefixed to the angles are those from the sector to the point observed*. The devia- ♦ Call S the signal at the station, P the adjacent place of the sector, and O the distant signal observed; then add the log. cosine of the angle SPO of Inglehorough above the Level of the Sea. 433 tion of the line of collimation from its mean value for each campaign is arranged in the last column ; the bisections ben)g marked D, F, or W, accordingly as they were made by the dot, filament, or wire. ^t Clougha West Pike. Dates. (A.) August 20, 1829, from 3 to 4 p.m. Sector on board. Eye 3^ feet above the ground between the pikes. — (B.) October 18, 1830, at 3 p.m. Eye 4J feet.— (C.) Sep- tember 18, 1832, from 1 to 3 p.m.. Sector on a pile of stones and sods. Eye 3 feet. Date St^ference. Station, ^c. observed. Distance. I » { Ingleboroiigh f do! '.'. '.'. .. C<( do, 1^ do. [tower top -\-22-S] A Hest Breakwater Pole, top C do. ...... C Black Comb C FarletonKnot C Hiitton Roof Moor .. .. C Warton Crag . . '. . . . A do. I . s Lancaster Church tower, top ^ I do. ! B do. ' Ft. 81522 8*1520 8*1343 35590 35587 158943 68036 59132 46933 46937 24558 Angle. 0 36 44 0 36 42 0 36 40 0 36 39 0 37 32 2 10 2 9 0 2 0 29 0 31 1 3 1 4 2 40 19 2 40 24 2 40 31 El. Dp. El'. Dp. Dp. Dp. Dp. Difflqf Level. Dev. CoU. Ft. I + 1015-0 + 1014.2 + 1012-8 + 1012-2 + 1009-0: -1318-4 -1312-5 + 630-3' 482-2: 458-71 817-4 825-0 -1129-8 1 130-4 1 1130-2 'F. At Aqueduct Bank. Dates. (D.) August 21, 1829, from 4^ to 5j p.m. Eye 6 feet above the Lancaster Canal when full (?). — (E.) August 25, 1829, from 10 a.m. to noon. Eye, 6 feet. Sector on board both days. E Inglehorough 1 do. do. >[+lft-] do. I do. J j)|CloughaPike-j ^^^^^ ) f' Uiketo J { Ft. 0 / // 1 r 91528 1 19 55 El. ' 1 19 40 *\ ... 1 19 47 1 ... 1 19 45 I. ... 1 19 38 . , 1 24822 2 56 9 El. ... 2 56 14 .. 2 56 18 L ... 2 56 14 Ft. I J310-01 + 2303-16-5- +2306-512 + 2305-615 + 2302-5 2 + 1 285-6' 1 + 1286-l'4 + 1286-714-5 + 1286-21 to the log. distance S P, and the sum minus radius will give a correction which, added to or subtracted from the distance S O accordingly as the angle S P O is obtuse or acute, will give that of P O. * At Inglehorough the eye must be elevated 1 foot above the base of the signal to clear the view of the Aqueduct Bank. Third Series. Vol. 6. No. 36. June 1835. 3 K 484« Mr. J. Nixon 07i the Trig07iometrical Height [Aqueduct Banlcy continued.'] jv J LancasterChurch tower, top \ do. do do. [N.W. pinnacletop-f 9*7] Ft. ) 7412 f ^ h El. Ft. + 156-5 . 1 9 20 ... + 156-7 ... 1 9 17 ... + 156-6 ] - 1 13 43 ... + 156-5 1.5 \^- 5-5j At Aqueduct Bridge, Date. (Y.) July 24, 1832, from noon to 1 p.m. Sector on south end of eastern battlement of bridge. Eye 1 3 feet above canal when full. yj rlngleboroughl [Tower top/ ^ t do. / +22-3] I Y / LancasterChurch tower top* L do. Ft. o // i; Ft. 91365 1 20 16 El. +2300-9 ... 1 20 18 ... + 2301-5 7416 1 6 5 El. + 156-8 ... 1 6 3 ... + 156-7 !.5}W ^t Hutton Roof Moor, Dates, (O.) October 1, 1830, from 0\ to 3^ p.m.— (P.) Oc- tober 2, 1830, from 10 a.m. to 3 p.m. — (Q.) September 13, 1832, from 3 to S\ p.m. Sector each day on a pile of stones. Eye 4 feet above base of signal. Q / Breakwater Pole, top t do. r do P< do L do. P Ingleborough ^ r do. I [Tower, top J \ do. { do UTower.top ^ da / +22-3] Warton Crag do. Farleton Knot j LancasterChurch tower, top \ do. , do CloughaPikeSjground betw Black Comb Ft. 45299 61513 61505 ei'311 61*304 26032 10155 57668 59145 140482 8 33 Dp. 8 42 8 27 8 23 8 42 17 46 17 54 17 50 19 17 19 18 19 18 50 a 0 50 5 0 10 30 Dp 0 44 18 Dp 0 44 26 ... El. Dp. 0 44 0 22 0 16 23 18 19j El. El. Ft. - 856' - 858- - 854' - 854' - 858- + 1475- + 1478- + 1477- + 1475" + 1475- + 1475- - 360« - 361 - 24' - 668" - 671- - 670- + 461- + 1088 .5-1 •0/ 2-5 2-5 1 14-5 5 5 3 n 2-5 0-5 3 2 8 3 3-5J F. I'^- ^D. At Warton Crag, Dates, (F.) August 21, 1829, from 11 a.m. to H P.M. « According to Mr. Binns, the tower is 97 feet 6 inches high, and the (levelled) fall from its base to the canal when full, 59 feet 1 1 inches 6 tenths; togetlier 157^ feet, or 1 foot more than by the above measure- ments. Taking the mean, the church tower top will be 157 feet above the canal, and 187 feet 4 inches (= 157+30-4) above the top of the Breakwater Pole. of Inglehorotigh above the Level of the Sea, 435 Sector on board. Eye 4 feet above the ground at the signal. — (G.) October 4, 1830, from llj a.m. to \\ p.m. Sector on the rock. Eye 5 feet.— (H.) October 15, 1830, from 1^ to 2^ P.M. Eye 5 feet.— (I.) July 25, 1832, from 6^ to 7 P.M. Sector on board. Eye 3j feet. Ft. Hest Breakwater Pole, top \ 20830 F H I P H [■ do. do. do. do. Ingleborough'i do. do. do. do. do. lo. do. do do [-247] [Tower > top. ■ +22-3] {. £ } [+1-0] 1 p / LancasterChurch tower, top \ do. F Hest Wall, top F Cloiigha West Pike, top 1 [+6-5] / F Farleton Knot G Hutton Roof Moor E Horizon of the Sea to the 1 S.S.W. atl^-SS-^P-M.*/ 20836 20834 20836 81847 81837 82046 36097 22227 46944 29346 26032 158520 I 24 2 24 24 24 23 47 28 3 12 4 11 58 11 51 11 51 12 8 12 8 11 53 11 0 10 58 10 59 0 32 14 0 32 13 1 12 7 0 56 55 0 36 53 0 45 8 ?0 23 5 Dp. El. Dp Dp. El. El. El. Dp. Ft. - 495-1 - 495-8 - 4960 - 495-1 - 494-7 - 495-9 + 1840-3 + 1837-9 + 1835-2 + 1835-2 + 1841-3 + 1841-3 + 1835-8 + 1839-5 + 1839-1 + 1839-1 - 306-9 - 306-9 - 451-9 + 821-5 W. •5 Id. 2-5 W. 5-51 ^Hd 4-5 f^- 4-5J V- D. 2 3-5 3 n 3 i 3-5J 7 337-1 361-1 528-2 11-5 W. At Ingleborough. Dates, (S.) September 2, 1829, from 11^ a.m. to 3 p.m. Remarkably clear. Sector on signal pile. Eye 4 feet above its base.— (T.) October 26, 1830, from 12^ 30"^ to 2'^ 30™ p.m. Very clear, but intensely cold, with flakes of snow. Sector as before. Eye 4 J feet. * It has been demonstrated at page 270, vol. v. that the included arc will be equal to the observed dip plus twice the refraction ; consequently when the latter is ^ the apparent dip will be to the arc as 15*5 to 17-5 The angle (23' 5") increased in this proportion becomes 26' 4", for which / 26' 4" \ arc the refraction will be 1' 29"-5, and the curvature (^— g— =) 13' 2". With the distance corresponding to the arc (158520 feet,) and the tangent of the dip, corrected for curvature and refraction (=11' 32^") the height of the eye will be 532-2 feet and that of the Crag 528-2 feet. 3K2 436 Mr, J. Nixon oti the Trigonometrical Height T T{ s s Ingleboroiigh tower, top Farleton Knot do. Hiitton Roof Moor ... do Clougha Pikesjg round betw. do. do do LancasterChurch tower, top Black Comb do do Ft. O / II Ft. 188 5 23 42 : El + 22-3,, 67990 1 21 0 Dp. — 1500 8 0 -] ... 1 20 57 ... -1499-8 35 61513 1 27 2 ,,, -14732 0 ... 1 27 8 ,,, -14750 6 81530 0 49 0 ... -1017-6 0 ,,, 0 49 0 ... -10176 05^ ... 0 48 48 ... -] 012-8 3-5 ... 0 48 54 ... -1015-2 75 97198 1 23 3 ... -2145-2 1-5 201970 0 21 16* ... - 383-8 0 ... 0 21 6 ... - 374 1 1-5 ... 0 21 10 ... - 378 0l3 J I.D. At Hest Breakisoater Pole, Date. (R.) October 21, 1830, from 10 to 10| a.m. Sector on board. Eye (3i feet above base,) 24^ feet below top of pole, which is 28 feet high. Ft. rClougha West Pike, top "1 05504 [+5-0] L do. do. R Hutton Roof Moor 45299 o / 2 7 7 24 3 41 El. + 1317-26.5- + 1316-9 0.5 + 858-10-5 At Farleton Knot, Dates. (J.) Aug. 28, 1829, at 2 p.m. Sector on a rock. Eye 1 foot above base of signal ; (a tremendous gale from the north.)— (K.) Aug. 29, 1829, from 10 a.m. to 2^ p.m. Sec- tor on a pile of stones. Eye 1 foot. — (L.) Sept. 30, 1830, from 3 to 5 P.M. Sector as last. — (M.) Oct. 12, 1 830, from 1 1 a.m. to 1 P.M. Sector as last.— (N.) Sept. 15, 1832, from 3^ to 4^ P.M. Sector on board. Eye 1 footf. M Hest Breakwater Pole, top Ft. 49983 0 / // 1 1 2 Dp. - 833-6 '^•5 D. N do. 49994' 1 0 58 iH - 832-8 4-5 F. J Ingleborough, 67990, 1 10 55 El. + 1501-0 1 W. K do. 67985, 1 10 36 + 1495-0 L do. 67987| 1 10 50 + 1499-6 1-5 D. r do 67986, 1 10 50 + 1499-6 ^ 1 N< do. 1 10 45 .. + 1498 0 4 .F. I do. 1 10 44 .. + 1497-7 3-5J H do.1 r 67793 1 12 9i .. + 1498-6 5-5" do. 1 12 15 .. + 1500-6 4-5 r do. I [Tower, top J do. f +22-3] ^ 1 12 13 .. + 1500-0 2 5 ^D. M^ 1 12 12 .. + 15000 2-5 [ L do. do.J t 1 12 8| .. + 1498-4 3 J N 67792 1 12 17 + 1501-4 ,3-5 F. • By Mudge, 22' 24" ; (height of Eye 5| feet.) t The beds dip 30*^ to 40° from the edge of the cliff* on which the signal stands. of Inglehorough above the Level of the Sea, 437 jr r LancasterChurch tower, top \ do. L do. K Warton Crag L Hutton-RooV Moor K Hest Wall, top .. rCloughaWesfS K^ Pike, top >[ + 6 L do! [ + 5-0] ly. f Black Comb \ do. . . Ft. o / // Ft. II top 63992 0 39 25 Up. - 646-2 2 ' .. 0 39 26 - 646-6 4-5 , , 63991 0 39 26 - 646 6 8 29344 0 41 40 Dp. El. - 336-3 1-5 10145 0 7 4 + 24-0 2-5 r 51140 0 67 1 Dp. - 791-7 2 l| 68037 0 19 40 El. + 481-6 1 I 0 19 34 + 479-5 3 1 0 19 36 -f 481-5 2-5 134460 0 18 30 El. + 1106-5 6-5 •• 0 18 28 •• + 1105-3 1-5 At Hest Wall. >D. Dates. (U.) Aug. 24, 1829, at 8 P.M.— (V.) Sept. 14, 1829, at 12^ P.M.— (W.) Sept. 16, 1829, at 3 p.m.— (X.) Oct. 20, 1830, at 11 a.m. Eye 0^ foot above Wall top. U Warton Crag V do. . . W do. . . V ( Hutton-Roof Moor ■^ \ do. U Farleton Knot V do. W do. . Aug. 24, 1 829. BreakwaterPole, top 25, 1829. July 25, 1832. Aug. 24, 1829. Aug. 2*5, 1*829. Oct. 14, 1*830. Oct. 2*0, 18*30. do. do. do. do. do. do. do. do. do. do. do. do. base do. do. do. do. do. do. do. Ft. 46052 51149 2339-3 / // 8 10 1 8 17 1 8 17 0 56 27 0 56 27 0 49 5 0 49 22 0 49 24 1 4 58 4 58 5 4 45 46 46 13 46 0 46 28 1 46 23 1 45 46 1 46 28 1 46 6 El. El. El. Dp. Dp. Ft. +451-7 + 452-5 + 452-5 + 814-8 + 814-8 + 7860 +790-4 + 790-9 -43 2 — 71-2 1 W. 6-5^ 0-5 0 0-5 1-5'W. In 1829 Hest Bridge top measured 17 feet above the Lan- caster Canal, and 4'2 feet above Hest Wall; whence the Wall is 12'8 above the canal. The Pole top being 43*2 below Hest Wall will be 30*4 lower than the canal. The following table exhibits for every intermediate station each day's observed difference of level between Ingleborough and the Breakwater Pole top, derived as well directly as through the medium of Lancaster church tower and Hest Wall, together with their respective heights above the Pole. When an observation of the hill was not accompanied on the 438 Mr. J.Nixon on the Trigonometrical Height same day by one either of the pole or church, the deficiency was supplied from the mean of all those registered. At Cloiigha Pike | At Aqueduct Bank | ^ At Aqueduct Bridge 2 AtWartonCrag < j U At Hutton-Roof Moor 2 0bs. 3 — At Farleton Knot |3 - L4 - By B.Pole ByL. Church. By Hest Wall. A 23300 2332-1 C 2323-6 2328-7 D 2340-6 23410 E 23350 2335-4 Y 2331-8 2332-0 F 2334-7 2333-5 2334-3 G 23330 2331-4 2332-8 H 2330-9 2330-1 2330-9 I 23360 2335-6 2336-4 P 2331-0 23330 Q 2333-5 2334-5 J 2334-3 23350 2335-9 K 2328-2 2328-a 2329-9 L 2332-8 2333-6 2334-6 M 23330 2333-4 2334-4 N 233«-0 2333-1 2334-1 Means. 2333-5 2332-9 2333-4 2333-9 2332-4 2333-2 2334-1 2333-0 Mean of ea»h day's obs. Do. of all the obs. The altitude may be found exclusively from the depressions, at Ingleborough, of Farleton Knot, Hutton-Roof Moor, Clougha Pike, and Lancaster church tower, together with the elevations of the three stations above the pole, as measured at the Breakwater and Hest Wall, and that of the church tower as determined by levelling, &c. By obs. of Farleton Knot .... 2332-5^ Hutton-Roof Moor 2332-1 \^j ^^„^ . n . Clougha Pike .... 2332-8 f ^^''^"' ^^^^'^ ^^^^' Lancaster Church . 2332-6J Giving the due weight to the different methods, the height of Ingleborough above the top of Hest Breakwater Pole may be considered as 2333 feet. Height of Hest Breakwater Pole above the Tides, Having filled up by interpolation the eight blanks in the given list of the observed heights of the Pole top above high water, from July 7 to August 7, 1832, the mean will be 26 ft. 8 in. By Holden's Tables, which are founded on five years' observations at Liverpool, and are considered very exact, the predicted mean height of the (day) tides within the same period is 14 ft. 10 in. above the old dock sill, which is 8 ft. 9 in. above the average low-water mark of spring tides, and 1 ft. 9 in. above that of neaps. To render Holden*s heights of Inglehorough above the Level of the Sea. 439 comparable with those of our list they must be subtracted from 41 ft. 6 in. (= 14 ft. lOin. + 26ft. 8 in.), when each day's difference will stand as follows: 1832. July 7th . . + 5 inches. (8 ..+10 9 ..+10 10 ..+ 7 11 ..+12 12 0+ 6 13 ..+ 6 14 ..+ 1 15 ..+ 3) 16 ..+ 7 17 ..+ 2 July 18th..— 2 inches. (July 29th.. + 3inches) 19 ..- 7 30 ..- 8 (20 C- 9) 31 ..-11 21 ..-12 Aug . 1 ..—14 (22 ..- 2) 2 ..-12 23 ..+ 1 (3 D- 9) 24 . - 1 4 ..- 8 23 ..+ 3 (5 .. 0) 26 ..+ 3 6 ..+ 2 27 • + 1 7 ..— 5 (28 ..-2) At high 'water the difference of level between spring and neap tides may be considered the same at both places. Call PO the observed height of the pole top above the sea in a given state of the tide, and PH its corresponding mean value for 1S32-3, derived from Holden's Tables. 1. At spring tides* PH will be 23 ft. at mean high water, and 50*3 at mean low water. July 28th, 1832, PO was 22*6, and the height of the tide (at Heysham) 29-3; whence PO would be- come 51*3 at mean low water, spring tides. 2. At neap tides^ PH is 29*6 at mean high water, and 43*3 at mean low water. July 20th, 1832, PO was 28*10, and the height of the tide at Heysham 18*3; whence PO may be stated at 465 at mean low water neap tides. 3. At mean high water PH will be (23 + 29*6\ j=26'35 or 26*2 by the mean of every day tide within the two years. 4. At mean '50-3 + 43-6 /50-3 + 43-6_\ i6-10, and PO = 48-10 low water PH / 51'3 + 46-5\ is 2 / ' \ 2 5. At the mean level of the sea PHwill be 36*6; the measure- ments at Heysham give PO = 38 at neaps and 37 at springs, mean 37*6 f. January 29th, 1823. Mr. Binns levelled from the canal at Hest to the shore 400 yards to the northward, and thence 1923 yards on the sands to the lowest (?) part of the channel of the KeerJ, and found the fall 76*9 (or 46*5 below the pole). • Spring tides were considered the two highest, and neap tides the two lowest tides within a lunation. t At Liverpool the difference of level between springs and neaps is much the same at high and low water, or about 7 ft. ; but at Heysham the dif- ference at low water cannot exceed 5 ft. It may therefore be doubted whether the lake subsides at spring tides to the level of the open sea. :{: " A small channel near the land at Hest was lower by 3 inches than the point levelled to.'* 440 Trig07iometrical Height of higlehorough. As the title measured 25*9 in height, it would have been at high water 20*8 below the pole top, or about the level of the highest tide in my list ; at least a 30-ft. tide. It may therefore be concluded, as indeed Mr. Binns intimates, that the point levelled to was some feet above low water. In proof, he states that the canal, when full, is 76^ ft. above the sill of Glasson dock gates, (consequently about the level of the channel of the Keer,) from which the tide sometimes ebbs out three to five feet. The height of Ingleborough may now be stated as 2370'5ft. above the mean level of the Irish Sea, and as 2384*5 ft. above meaii low water spring tides * ; 2379-5 — — — neap — 2356*0 — mean high water spring tides; 2362*5 — — — neap — . The height of each sector station above mean low water spring tides, obtained on the same plan as that of Inglebo- rough, is given in the following list. By obs. at Breakwater . . Hest Wall . . . . Warton Crag . . Farleton Knot Hutton-Roof Moor Cloiigha Pike . . Ingleborough . . . . Aqueduct Bank Mean Warton Farleton Hutton- Clougha. Crag. Knot. Roof Moor. 1368-3 909*4 546-7 883 6 909-3 i 367-5 5461 883-1 907*1 1365-8 548-5 884-9 908-9 1369-8 547-3 883-3 9081 1369-3t 544*3 884-0 907*5 1368*1 883-7 909-8 1368*1 1368-1 546*6 883*9 908-6 1 Having measured from three intermediate stations in Wharfdale, the difference of level between Ingleborough and Roseberry Topping, the resulting altitude of the latter ex- ceeded considerably its elevation above the German Ocean at Redcar, as measured by Col. Mudge from the intermediate station at Burleigh Moor. It is however evident that either the data for determining its distance from Burleigh Moor are incorrectly stated, or that an error of — 1802 feet ( = — 33 ft. in the altitude,) has been committed in the calculation. The height of Black Comb measures 1989*8 from Farleton Knot, 1997-4 from Hutton-Roof Moor, 1998*4 from Clougha, and 20057 from Ingleborough; mean 1997*8. Col. Mudge states it at 1919 feet. Chapel Allerton, near Leeds, JoHN NiXON. Feb. 5th, 1833. * Hitherto called 2374*5 ft. Mudge makes it 2361 ft. f Rejecting the obs. marked (C). X Summit of moor, 91 16 ft. [ 441 ] LXX. On a Decimal Si/stem of Monetary Calculation, founded on the present Denominations of Mo7iey and Coins in Great Britain, By Mr. Samuel Read, Member of the School of Naval Architecture, To the Editors of the Philosophical Magazine and Journal, Gentlemen, "lyl/'HILST everybody admits the superiority in every re- ^ ^ spect of a decimal system of calculation in regard to vy^eights and measures and money, and at the same time can only regret that the habits we have imbibed prevent the exe- cution of such a desirable measure as the introduction of a decimal graduation of our monetary scale, I have not seen or heard of any attempt to develop such a system from the pre- sent money table, which, remarkable as it may appear, con- tains a decimal graduation perfectly available in all money calculations, and with a very slight expense might be in- grafted on our present coinage. Assuming the shilling as the unit, and having one copper coin of a new value, the whole of our present coinage may be adapted to the decimal scale, which I shall presently deduce from the money table now in use. We shall not have to for- get any of the present denominations of money, or to interfere with deeply rooted habits and prejudices, or to put the country to any other but a very trivial expense in effecting the altera- tion. Taking, therefore, the shilling as the unit, I conceive it to be divided into ten parts, each of which cannot perhaps have a more significant name than a "tenth"; a "tenth" I sup- pose also to be divided into ten parts, each of which, from being the y^^dth of a shilling, may very properly be called a "cent"; hence the decimal graduation we have just now in- dicated only wants a step above the shilling to complete it, and that we most fortunately have ready to our hands in the " half- pound." The money table for calculation may therefore be thus simply constructed : 10 cents equal 1 tenth, 10 tenths 1 shilling, 10 shillings 1 half-pound. From a consideration of the above table it therefore appears that the only new piece of money absolutely necessary to con- nect the present coinage with this decimal scale is the copper " tenth," for this copper " tenth " would have a value of 12 penny ; hence the present farthing would only be y^^dth of a TTiird Series. Vol. 6. No. 36. June 1835. 3 L 4-42 Mr. Samuel Read on a Decimal System penny in excess of two " cents " ; the cent being of course an imaginary denomination, and only necessary for the purpose of calculating by an uniform scale. In the same way the present halfpenny would be only j-§^ or j^ of a penny in excess o^four cents ; and lastly, the present penfiy-p'iece would be ^^ of a penny in excess of eight cents. We see, therefore, that the wear of the present copper coinage would soon cause, if it have not already caused, an equality, or a very near approximation to equality, between the present penny and 8 cents, between the present halfpenny and 4 cents, and between the present farthing and 2 cents. The comparison may, however, be bet- ter exhibited at one view as in the following table : Proposed Present Scale. Scale. Present Coin. 2 cents equal to '24? of a penny, or very nearly o«^ farthing, 4f — — '48 — or — ow^ halfpenny, 6 — — '72 — — — three farthings, 8 — — '96 — — nearly one penny ; and 10 cents would be represented by the proposed copper coin the " tenth." In proceeding up the scale of our present silver coinage we have the following comparison : 5 tenths equal ... 1 sixpence, 10 — ... 1 shilling, 25 — ... I half-crown, 50 — ... 1 crown. A tolerably simple progression of value, in as much as the third value, or half-crown, is five times the five-tenth piece, or six- pence, and the fourth value is also five times the shilling. It appears, therefore, that all the silver coins at present in use, with the exception of the half-crown, will be integral values of all the denominations of money our decimal scale has indicated. If, however, the gradual introduction of two new silver pieces were allowed instead of the crown and half-crown, a much more simple progression might be adopted, having a Series of values derived from the five-tenth piece, or sixpence, in the manner of a geometrical progression, whose common ratio is 2. Such an improved scale would stand thus : 5 tenths equal ... 1 sixpence, 10 — ... 1 shilling, 20 — ... 1 half-noble, 40 — ... 1 noble. The revival in this table of a famous old English coin would put a much more convenient description of silver money into of Monetary Calculation, 443 circulation than tJie present crown and half-crown pieces, the former of which, in particular, from its large size, is ill adapted for carrying in the pocket. As the highest denomination of money in the decimal scale proposed is the " half-pound," all gold coins ought to have some multiple value of the same. We have already the half- sovereign often shillings and the sovereign of twenty shillings, to which might be added a cimal Valu Half-Poi i ^z •0020 ^ = •0041 f = •0062 1 = •0083 u =: •0104 If =r •0125 1: = •0145 2 = •0166 n = •0187 n =: •0208 n =s •0229 3 = •0250 d. D( HJimal Valu Half-Pou Si = •0271 Si = •0291 3| = •0312 4 = •0333 H = •0354 H = •0375 4J =r •0395 5 sz •0416 H = •0437 H = •0458 H = •0479 6 = •0500 Being desirous of giving publicity to the results of my in- quiries on this subject, I have put them into the present form, in the hope that you will be able to find for them a spare page or two of your valuable scientific periodical. I beg to remain, Gentlemen, Your obedient Servant, His Majesty's Dockyard, c, t> Chathara/Feb. 4th, 1835. SaMUEL Read. LXXI. On the Immersion of Copper for Bolts and Ship- sheathing in Muriatic Acidy as a Test of its Durability, By David Mushet, Esq, T^HE durability of copper for bolts and ship-sheathing being -■- an object of great national importance, and as there is no better test of its resistance to waste than immersion in mu- riatic acid, the following experiments, made thirteen years ago, will, it is hoped, be found not uninteresting. Small quantities, presenting nearly equal surfaces of each of the kinds of copper described in my last communication, p. 324, namely, pure shotted copper of the quality from which brass is made, and shots obtained from unrefined copper, were se- parately immersed in equal weights of muriatic acid. The immersion having been continued for forty-eight hours, the acid was poured off, and the copper washed repeatedly and cimal money table for the term " half-pound ;" our accounts being kept in regents, shillings, tenths, and cents, instead of halt-pounds, shillings, tenths, and cents. For this suggestion I am indebted to a friend well known in scientific circles, and to whom I have communicated the subject-matter of this paper.— AfarcA Uth, 1835. S.R. in Muriatic Acid^ as a Test of its Dtirahility. 445 thoroughly dried. The pure copper had lost at the rate of 5J grains in 100. But the unrefined copper, on being weighed, seemed to have gained half a grain ; so that either a mistake must have been made in the weighing, or else a portion of unexpelled moisture had remained in the porous flakes of the copper. Six ounces of unrefined copper were mixed with three times their bulk of charcoal, and exposed for six hours to a high heat of cementation, much beyond what in the absence of the cementation would have sufficed to melt the copper. The flakes of copper were found surrounded by the charcoal, welded together without fusion, and soft and extremely flexible. Six ounces of the pure copper shots were treated in a similar manner ; but the result was so far different that no adhesion of the masses had taken place, and the only percep- tible change was a slight cracking or bursting uj)on the sur- face of the spheroids, which may be considered as a prelude to fusion. Both results were melted down with charcoal and run into iron moulds. The unrefined copper, when cold, was the strongest and softest ; a bar of it, about f ths of an inch thick, cut easily across with a knife, and in colour and general appearance it very nearly resembled Swedish copper. Ano- ther piece was flattened out thin when cold for the purpose of immersion in the muriatic acid. The pure copper was melted in rather a higher degree of heat, and although not teemed until it had assumed a creamy surface, and the crucible had fallen to a low red temperature, it was crystallized through- out the whole fracture. The surface and the fracture of this copper were of a red colour ; the body weak, and tearing with facility into pieces. Fragments for immersion were cut off and flattened. The following specimens were then placed separately in muriatic acid. - No. 1. Pure copper, cut off with a chisel, ... 53 grains. 2. Ditto, flattened, ... 30 — 3. Unrefined copper, cut off with a knife, 39^^ — 4. Ditto, flattened, in which stuck ^\ aq minute portion of the knife J On the morning of the third day the following remarks were made upon their respective solutions. No. 1, Light green colour, very transparent when dashed against the sides of the glass. No. 2, Equally transparent, but the green was brownish and not so decidedly cupreous. After continuing the immersion for 48 hours longer, the acid was poured off and the specimens were well washed and dried. 446 On the Immersion of Copper in Muriatic Acid, No. 1, That weighed 53 grains, now weighed ... 39^ grains. Loss 1 3^ grains. Equal to 25*4' per cent. No. 2, That weighed 30 grains, now weighed ... 11^ — Loss 18^ grains. Equal to 61*6 per cent. No. 3. Unrefined copper flattened, 39 J grs.,"! -q now weighed ... j Loss 20i grains. Equal to 50 per cent. No. 4. Unrefined copper bar, 42 grs., now weighed 38^ — Loss 3^ grains. Equal toSy^^^ percent. It would appear from this experiment that the unrefined copper resists waste in the muriatic acid, in the same way, and to nearly the same extent, as in the cementation with lime mentioned in my last previous paper, p. 325. In corroboration of this fact, we may take the following abs- tract of another series of experiments, wherein the specimens were weighed three times, at intervals of 48 hours between each weighing. Unrefined copper, 1st immersion, lost... 15 percent. Ditto, 2nd do. ... 8y% — Ditto, 3rd do. ... 6 — 29A~ ... 25-4 — ,.. 9-7 — ... 11-1 — copper, 1st immersion Ditto, 2nd do. Ditto, 3rd do. 46-2 — In favour of the unrefined copper, principally containing tin, — 169 percent. Two pieces of copper, the one pure the other unrefined, were immersed, under similar circumstances, for seven days. The unrefined copper lost 17 per cent, and the pure copper 45 per cent. To ascertain whether the greater indestructibility was owing to the tin which remained in the unrefined copper, I formed a bar of alloy as follows : Pure copper ... 2880 grains. Block tin ... 84 — A proportion of tin about equal to 3 per cent. A piece from this bar, weighing about 183 grains, was exposed for seven days in muriatic acid, at the end of which time it was found to have lost 30 grains, or 16y*^ per cent. The unrefined cop- per above mentioned lost, in the same time and under similar circumstances, 17 per cent., which is a striking correspon- dence. The same piece of tin alloy, at the end of five weeks, was found to have lost in all 76 grains, or 38 J per cent. Pure Mr. Westwood on new Dipterous Insects, 447 copper by the foregoing results lost in seven days' immersion 46*2 and 45 per cent. In the first instance 1 was inclined to attribute the inde- structibility of the unrefined copper in the acid partly to the effects of the charcoal in the cementation, seeing that the effect produced by that operation was much greater upon unrefined than upon pure copper. Whatever advantages may belong to the proper use of charcoal in the reduction and cemen- tation of copper, (and I consider them not unimportant,) the addition of a small portion of tin will be sufficient to account for the superior resistance to waste which this alloy presents in the muriatic acid, over that of the common refined copper of this country. This incapacity to rapid oxidation which is presented by the alloy of tin with copper, suggests many useful hints to the artist and the manufacturer, of which advantage has already been taken in forming ship-sheathing and other articles. David Mushet. LXXII. Insedorum nonnullorum exoticatmm {ex Or dine Di- pterorum) Descriptiones. Atictore J.O^W^estwood, F,L.S» 4"^. [Continued from p. 281.] PHILOPOTA, Wied. Maculicollis, Westvf. Nigra ; thorace antice roa- culis 2 minutissimis, alterisque 2 parvis ad basin alarum fulvis; abdo- minis marginibiis tenuiter flavo notatis, segmentis terminalibus, sericie subaurea tectis ; antennis nigris ; facie albid^ ; femoribus nigris, apice rufis, pedum geniculis pallidis ; alis infumatis. — Long. corp. lin. 4|. Exp. alar. lin. 1 1^. Habitat in Brasilia. *' Capta D. Swainson." In nms. nostr. Lepidophora, Westw. (Fam. Bombyliidcs,) Antennae capite triple longiores, squamulis obtectae, articulo Imo? brevi, 2ndo longo gracili, 3tio breviori latiori, stylo apicali. Proboscis an- tennarum dimidio brevior. Thorax valde gibbosus. Abdomen elongatum, parallelum, cauda squamulosa ornatum. Alae farinosae, nervis ut in Cyllenia dispositis. Pedes longi, graciles. Obs. Cel, Kirby et Spence hoc genus coramemorant libro " Introd. to Ent." vol. iii. p. 646, pi. 12, f. 23, ubi Culicem cum Anthrace, &c., conjun- gere credunt. Sp. 1. Lep. (Bgeriiformis, Westw. MSS. Ploas (Egeriiformis, G. R. Gray, in Griff. An. K. pi. 128. Niger; thoracis lateribus flavo pubescentibus; abdomine maculis 6 latera- libus flavis; alis infuscatis. — Long. corp. lin.5^— 6i. Exp. alar. lin. 11 — 14. Habitat in Georgia Americae. — In Muss. Brit, et nostr. Obs. Toxophora lepidocera Wied. congenerica videtur. Nemestrina, Latr. Rhynchocephalus, Fisch. FaUenia, Meig. t. 2. Subg. 1. JVr^nw!, Macq. Palpi elongati, attenuati; antennarum stylo 448 Mr. Westwood ofi new Dipterous Insects, cylindrico; alarum cellula 3tia submarginali minuta, clausa. — Ci/therea ^asciata. Fab. Subg. 2. Nemestrina proprie sic dicta. Palpi minuti; articulis rotundatisj antennarum stylo setiformi 3-articulato ; alarum regione apicali valde transversa reticulata; oculis laevibus. — N, reticulata, Latr. j longirostris, Wied. Subg. 3. TrichophthalmafW est. Palpi magnitudine intermedii ; articulis plus minusve ovalibus; antennis ut in subg. 2; alarum regione apicali longitudinaliter nervosa, nervis ut in Fall, caucasicd (Meig. vol. 2. 1. 16, f. 14.) dispositis, nervo fere recto, e medio nervi subcostalis, apicem versus marginis postici oblique currenti ; nervo 2ndo apicali furcato ; oculis pu- bescentibus. Hie pertinere videntur Rhync. Tauscheri Fisch., Meig. v. 6- pi. 66. f. 67. et Rhyn. caucasica Fisch., Meig. loc. cit.j etiam Trich. bivittatayW estw. Thorace cinereo; capita magno; oculis fulve- scenti-pubescentibus ; proboscide capite longiori ; abdomine nigro, vittis duabus longitudinalibus latis albis; antennis pedibusque rufescentibus ; alls hyalinis ; nervis costalibus et basalibus fusco-rufis, reliquis nigris. — Long, corp. (probosc. excl.) lin. 7. Exp. alar. lin. 16. Habitat in Nova Hollandia. — In mus. nostr. — Communicavit Dom. Shuckard. Trick, costalisy Westw. Thorace fusco; capitis facie alba; oculis piceo- pubescentibus; abdomine rufescenti-fusco'; basin et apicem versus corporeque toto subtus pubescentia albo-cinerascenti indutis; pedibus rufescentibus; antennarum articulis terminalibus nigris; alis elongatis; costa lat^ fuscanti; proboscide nigro ; capite paullo longiori. — Long. corp. (probosc. excl.) lin. 7. Exp. alar. lin. 17. Habitat in Nova Hollandil— In mus. nbstr. — Communicavit Dom. Shuc- kard. Trick, obscura, Westw. Obscure cinerea ; pedibus rufescentibus ; facie aM; proboscide capite fer^ duplo longiori; alis ad costam tenuit^r fus- cantibus ; ocello antico aliis remoto.— Long. corp. (probosc. excl.) lin. 5|. Exp. alar. lin. 14. Habitat in Africa ?— In mus. D. Hope. Trick, subaurata, Westw. Fusca; pubescentia subaurata tecta; thorace iateribus et in medio longitudinaliter pallidiiis bivittato; abdomine magis fulvescenti, vitta obscuriori centrali longitudinaii; pedibus et antennis ru- fescentibus, harum seta nigra, alis brevioribus ; costa late fuscanti ; probos- cide capite pliis quam duplo longiore. — Long. corp. (probosc. excl.) lin. 5^. Exp. alar. lin. 13^. Habitat in America meridionali (Valparaiso). In mus. D. Hope. Obs. Sectio 3tia supra descripta affinitatem generis NemestrincB cum Hermoneurd facile demonstrat, inde in ordine naturali genus Nemestrina locum intermedium tenet inter Cyrtum, Lasiam, &c. familiae Vesiculosarum et Hermoneuram familiae Anthracidanim. Obs. Genus Midas, neuratione alarum similiter insolita, gaudens ramulo laterali systematis, generibus supra praedictis conjungi videtur. An genus osculans ad Asilidas, &c. adducens ? Apiocera, Westw. Genus quoad habitum Midasibus, Corsomyzis et Nemestrinis approximare videtur. Caput transversum. Antennae capite breviores; articulo Imo crasso, 2ndo parvo, his articulis cum setis rigidis armatis ; 3tio parvo pyriformi ; seta minuta terminali. Proboscis exserta, capitis longitudine. Palpi exserti, spatuliformes. Abdomen thorace fere Astronomical Society, 419 diipld longiiis, obconiciim. Femora postica hand incrassata. Tarsi bipul- villati. Alarum nervi fer^ lit in A/wfafe dispositi ; nervo 3tio longitudinali, ante apicem furcato, recto; nervo 4to longitudinali supplementali, apice cellulae Imae discoidali exeunti, inde celiulte 4 posteriores marginales ef- formantur. Sp. 1. Ap. asilica, Westw. Nigra; vertice, thoracis lateribus piceijj; palpis albidis ; alarum nervis nigris.— Long. corp. lin. 9^. Expans. alar, lin. 17. Habitat in Nova Holland!^. — In mus. nostr. Sp. 2. Ap. fuscicollis, Westw. Obscure fusca ; tliorace cinereo sub* vittato ; palpis albidis; alarum nervis internis pallidis; corpore subtus albido villoso. An varietas praecedentis? — Exp. alar. lin. 17. Habitat in Nova HoUandia ? — In mus. D. Hope. Pangonia, Latr., Macroglossa yWestw. Pallide fusco-pubescens ; facie alba (ocellis 0), thorace vittis duabus longitudinalibus in medio, lateribus, et macula utrinque basin versus alarum albis ; abdomine piceo, segment© Imo fulvo-marginato, 2ndo et 4to albo-marginato, 3tio rufo-marginato, re- liquis fusco-marginatis ; alis basi et ad costam lat^ infumatis ; pedibus tes- taceis. — Long. corp. lin. 8|: long, probosc. lin. 15. Exp. alar. lin. 16. Habitat in Georgia Americae. — In mus. nostr. Pangonia macidiventris, Westw. Nigra ; thorace baud vittato ; abdomine rufescenti-fusco, serie dorsali macularum rotundarum nigrarum; alarum nervis (praesertim transversis) fusco tinctis ; pedibus fuscis ; corpore subtus pallidius pubescenti ; ocellis 3. — Long. corp. lin. 6|. (proboscide mutil^). Exp. alar. lin. 14. Habitat in Nova Hollandia. In mus. nostr. LXXIII. Proceedings of Learned Societies, ASTRONOMICAL SOCIETY. 1835, nPHE following communications were made : Jan. 9th. — -■- I. Mr. Sheepshanks exhibited a small clock, on Fraunhofer's principle, for giving motion to an equatorial, and ex- plained the construction and use of a moveable piece to be applied to the eye-end of the telescope, for the purpose of micrometrical mea- surements. Mr. Sheepshanks also exhibited a telescope fitted up as an equal- altitude instrument, similar to that drawn in Plate XIII. of Dr. Pear- son's " Introduction to Practical Astronomy," except that it has straight radii at the base instead of a claw stand. The purport of his remarks was to point out the various objects to which such an instru- ment might be applied in the hands of a traveller or amateur able and willing to calculate his observations. Such an instrument is evi- dently a tolerable theodolite and level, as well as a very firmly mounted telescope for common purposes, occultations, eclipses, &c.; and if the cross axis be made with care, it would suffice as a transit for the moon and moon-culminating stars in ordinary cases. But it is chiefly valuable as an equal aZ/i/Mr/e instrument, which it is made by an excellent level attached to a small quadrant on one side of the telescope. Further particulars of Mr. Sheepshank's communications on both subjects are given in the Monthly Notices of the Society. Third Series. Vol. 6. No. 36. June 1S35, 3 M 450 Astronomical Societjj: Sir J. Herschel's Observations II. Extract of a letter from Sir John Herschel to F'rancis Bally, Esq., dated Cape of Good Hope, October 22, 1834 : ** The climate proves much more favourable for astronomical ob- servation than, during the summer and autumn, I had found reason to expect. Since thesettingin oftheN.W.v^inds (in July, August,Sep- tember, and October, the season being at least a month later this year than usual), the nights have been frequently superbly clear and tran- quil, and the definition of stars far beyond anything I ever witnessed at home, allowing the habitual and agreeable use of magnifying powers such as could only be used in the rarest nights in England, and then with difficulty. A brief recapitulation of a few of the more interesting objects and remarks which have fallen under my notice may not be unpleasing to you. *' We landed on the 16th of January; and on the 22nd of February, the 20-feet telescope being erected and the mirrors unpacked, I turned it, for the first time, on the southern circumpolar heavens. The no- velty and variety of the objects then seen induced me to defer the commencement of regular sweeping till some of the principal among them had been examined, — such as the wonderful nebula about ri Ar- gus— the Magellanian clouds — the great cluster adjoining the Nubi^ cula minor, and that superb one w Centauri, &c. — and till habit had familiarized me with the delusive appearances assumed by objects under the influence of the S.E. winds, &c. " On the 5th of March my sweeps commenced, and have conti- nued, at the average rate of about 10 sweeps per month (cloudy and moonlight nights being, of course, nodes non), in the course of which 1 have already accumulated a pretty extensive collection both of ne- bulae and double stars ; though, in close double stars above the 10th magnitude, this hemisphere is decidedly poorer than the northern. " On the Istof April 1 discovered, in R.A. 9^ 17"S N.P.D. 147°35', a beautiful planetary nebula having a perfectly sharp well-defined disc 3" or 4" in diameter, and of a uniform light. Its appearance is precisely that of a small planet, with a satellite about 1^ diameter from its edge. Mr. Maclear has been obliging enough to determine its place with great exactness by the circle, by several observations, from which it appears to have no planetary motion. " On the 3rd of April I discovered another fine planetary nebula, having a perfectly sharp disc, without the least haziness, of about 6" diameter. The most remarkable feature about this is its evident blue colour, which needs not the presence of lamp light, or that of any red star, to be very conspicuous, as it appears when the nebula stands alone in a dark field. This also has since been (at my request) ob- served with the circle at the Royal Observatory. ** On the 26th of June I observed an extremely remarkable object, of the class of close double stars, centrally involved in a ne- bulous atmosphere. Its place is in R.A. IS'M/^'SO^i, N.P.D. 129° 9'+. The diameter of the nebula is about 2', and the stars are equal, each of them 9*10 mag., distance about ]-^" or 2". The nebula is nearly uniform, or, at least, very little condensed about the star. made at the Cajje of Good Hope, 451 " On the 28th of June I discovered an annular nebula in R.A* 17" 10'" 36% N.P.D. 128° 18' (all the above places are for January, 1830). It is exactly round, and perfectly well-defined, diameter 15", very faint, like that in Cygnus, and situated among an immense crowd of stars. " On the 2nd of July I was fortunate enough to light on another very delicate and beautiful planetary nebula in II. A. If)'' 5"" 15', N.P.D. 135° r (1830-0), having a diameter of I«-35 in time, and a perfectly sharp disc, equal to a star of the 8*9 mag. in light. (My assistant, J. Stone, to whom I showed it, said it was like the moon, round and clean, only smaller.) ** Among the more delicate and close double stars I have observed, either with the 20-feet, or the 7-feet equatorial (which I have suc- ceeded in mounting very satisfactorily under a revolving roof of a pe- culiar and very simple construction, which answers completely,) which I employ on moonlight nights for measuring double stars, and for the purpose of a review of all the stars in the Brisbane Catalogue (of which I procured from Mr. Richardson an index copy in MS.), I may mention the following : I Apparatus ^ Phoenicis X Eridani ... ^ Reticuli ... T Argus /3 Hydrae ... y Lupi •y Coronae Aust. .. Anonym , 22 Piscis Aust. h m o / Class. Magnitudes. 0 25 125 55 (6) (7-8) 1 2 145 9 (5) (9) 1 49 142 27 III. (4-5) (14) 4 16 153 41 (5) 10 15 145 11 (5) (10) 11 44 122 57 (5) (56) 15 24 130 34 (3) (3) 18 55 127 18 (6) (6) 20 37 153 2 (6) (6) 22 43 123 46 (5) (8) A most delicate object. FJxcecdingly close. i *Ithink this has been ( observed before. To which I may add also \ Octantis, &c. &c. " With much difficulty, and after almost despairing of arriving at anysatisfactory measures, I succeeded in procuring pretty trustworthy angles for y Firginis, about the predicted perihelion. The stars then were materially better defined than in May, June, or July. They, agree, within reasonable limits, with the calculated angle. " a CruciSy if Dunlop's measures are correct, is in a state of pretty rapid rotation, having described 7° since 1826. To the list of binary, stars I am at length enabled, unhesitatingly, to add ^ Libra, as the following series of angles will abundantly prove : — 1782-36 Pos. = 7° 58' .... H.Catal. 1825-49 .... 171 54 .... South. 1830-28 181 30 H., junior, Slough. 1834-35 189 3 Ditto, Feldhausen. This last measure was obtained under circumstances much more satisfactory than it is ever possible to obtain in Europe, from the low situation of the star. Neither can we doubt that 36 Ophiuchi is binary. Mayer makes 3 M 2 452 Zoological Society : Mr, Ossgw on a tnicroscopic the two stars exactly on the same meridian, and diff. decl. = 13". That is, 1780-+ Pos.360° 0' Dist. 13"-00 1822- .. 227 19 5''-55 1834-35 .. 223 34 4"'80 But, of all the double stars in the heavens, if Dunlop's measures of it are to be depended on, the star 6 (Bode) Eridani is, perhaps, the most remarkable. This star has occurred to me both in my 20-feet sweeps and in my equatorial reviews, and has been measured, in both cases, without being aware in the one what star it was — in the other, that it had been previously observed as double. By subsequent com- parison, the place identifies it with Dunlop's No. 5 (Ast. Soc. Mem. vol. iii., part ii., pp. 267 and 259). His angle is 73° 6' nf by 3 ob- servations, of which he states the particulars, in December J 825, that is to say, 1825*9, Pos. = 16° 54', in my notation ; whereas, by my sweep, with which the equatorial measures agree almost exactly, the position for 1834, October 5, was 121° 30', giving a rotation of almost 105° in nine years, or averaging 10°-67 per annum, which, if continued, would bring it round in a period of little more than thirty years. ** My mirrors tarnish with extraordinary rapidity. Half-a-dozen nights' sweeping dims their fresh lustre ; and three months' work so effectually spoils them, as to render it useless to go on. Happily I had taken the precaution to bring out a complete polishing appa- ratus with me, and have been perfectly satisfied with the efficacy of it, as you may judge I have reason to be, when I mention powers of 480, 800, and* 1200, as giving perfectly round and well-defined discs with an aperture of twelve inches ; and, on one occasion, 1 have car- ried the magnifying power as far (I believe, for I have no means of measuring it otherwise than by the focal length of the lens,) as 2000, without destroying useful vision. With a power 1200, and a reduced equilateral triangular aperture, a Eridani was, I think, the most re- gular, and beautiful object, on the superb night of the 6th instant, I ever beheld. My sweeping-book says of it, * The disc a perfect circle, and the six rays' (which the equilateral triangle always gives to large stars,) 'extending, like delicate, perfectly straight, white-hotrods, into the field long after the star was withdrawn from it.* " HI. Transits of the Moon with Moon-culminating Stars, observed at Cambridge Observatory in the month of December, 1834. IV. Observed Transits of the Moon and Moon-culminating Stars, over the meridian of Edinburgh Observatory, in December 1834, by Mr. Henderson. ZOOLOGICAL SOCIETY. Feb. 24, 1835. — A paper was read by Mr. Owen, entitled, "De- scription of a Microscopic Entozoon infesting the Muscles of the Hu- man Body." The author observes, that upwards of fifteen different kinds of internal parasites are already known to infest the human body, but none have been found of so minute a size, or existing in su«h astonishing numbers, as the species about to be described. Entozoon infesting the Muscles of tlie Human Body, 453 The muscles of bodies dissected at Saint Bartholomew's Hospital had been more than once noticed by Mr. Wormald, the Demonstrator of Anatomy at that establishment, to be beset with minute whitish specks ; and this appearance having been again remarked in that of an Italian, aged 45, by Mr. Paget, a student of the hospital, who suspected it to be produced by minute Entozoa, the suspicion was found to be correct, and Mr. Owen was furnished with portions of the muscles, on which he made the following observations. With a lens of an inch /oc«s the white specks are at once seen to be cysts of an elliptical figure, with the extremities in general atte- nuated, elongated, and more opake than the body (or intermediate part) of the cyst, which is sufficiently transparent to show that it con- tains a minute coiled-up worm. On separating the muscular fasci- culi, the cysts are found to adhere to the surrounding cellular sub- stance by the whole of their external surface, somewhat laxly at the middle dilated part, but more strongly by means of their elongated extremities. When placed on a micrometer, they measure ^Vth of an inch in their longitudinal and xwth of an inch in their transverse di- ameter, a few being somewhat larger, and others diminishing in size to about one half of the above dimensions. They are generally placed in single rows, parallel to the muscular fibres, at distances varying from ■^ a line to a line apart ; but sometimes a larger and a smaller cyst are seen attached together by one of their extremities, and they are occasionally observed slightly overlapping each other. If a thin portion of muscle be dried and placed in Canada balsam, between a plate of glass and a plate of talc, the cysts become more transparent, and allow of the contained worm being more plainly seen. Under a lens of \he focus of ^ an inch, the worm appears to occupy a circumscribed space of a less elongated and more regularly ellipti- cal form than the external cyst, as if within a smaller cyst contained in the larger : it does not occupy more than a third part of the inner^ space. A few of the cysts have been seen to contain two distinct worms ; and Mr. Farr, who has paid much attention to the subject, exhibited a drawing of one of the cysts from this subject, containing three distinct worms, all of nearly equal size. Occasionally the tip of one of the extremities of the cyst is observed to be dilated and ^ transparent, as though a portion of the larger cyst were about to be separated by a process of gemmation ; and these small attached cysts are seen of dififerent sizes, and, as it were, in different stages of growth. This appearance, however, Mr. Owen conceives to be explicable with- out a reference of a power of independent vitality to either of the adherent cysts. The cysts are composed of condensed and compacted lamella of cellular tissue ; but a few are hardened by the deposition of some earthy salt, so as to resist the knife and to produce a gritty sensation when broken under pressure. When removed from the interior of the cyst, which, on account of the minuteness of the object, is a matter of some difficulty, the worm is usually found to be disposed in two or two-and-a-half spiral coils. When straightened it measures from -jVth to -sVth of an inch in length, and from yi^^th to ^iryth. of an inch in <3iamcter : a high magnifying 45^ Zoological Society : Mr. Owen 07i a microscopic power is consequently required for its examination. It is round and filiform, terminating obtusely at both extremities, which are of un- equal sizes, and tapering towards one end for about a fifth part of its length, but continuing of uniform diameter from that point to the opposite extremity. As it is only at the larger extremity that he has been enabled to distinguish an indication of an orifice, Mr. Owen regards that as the head. He states that this indication has been so constant in a number of individuals examined under every variety of circumstance, that he has no hesitation in ascribing a large transverse linear orifice or mouth to the greater extremity. The recently extracted worm, observed by means of a Wollaston's doublet, before any evaporation of the surrounding moisture has af- fected its integument, presents a smooth transparent external skin, inclosing a fine granular and flaky substance or parenchyma. It is obvious that the test of coloured food cannot here be applied to elu- cidate the form of the digestive organs, but there is no appearance of the parietes of an alimentary canal floating in a visceral cavity and distinct from the integument of the body, nor was any trace of an orifice observed at the smaller extremity. Mr. Owen was also un- able to detect in any instance a projecting spiculum or hook at either extremity, or any appearance of the worm having been torn from an attached cyst. Its transparency is such as not to admit of a doubt as to its wanting the ovarian and seminal tubes, and the other characteristics of the complicated structure of Filaj-ia, Ascaris, and the Nematoid Entozoa generally. It is not of a rigid texture, but is extremely fragile, and exhibits when uncoiled a tendency to return in some degree to its former state. Mr. Owen refers to the genus CapsnJaria as established by Zeder, and rejected by Rudolphi, (who considers its species as belonging' either to Filaria or Ascaris,) for the purpose of contrasting the complicated organization of the worms composing it with the ex- tremely simple structure of the encysted worm under considera- tion. The circumstance of being inclosed in cysts he stated to be common to many very diff'erently organized genera of Entozoa. There are few, indeed, with the exception of those which live upon the mucous surfaces of the body, that do not, by exciting the adhe- sive inflammation, become inclosed within an adventitious cyst of condensed cellular substance. He regards the simple type of struc- ture exhibited by the minute animal now for the first time described as approximating it to the lower organized groups of the Vers Pa- renchymateux of Cuvier; and both from its locality and from the constancy of its cysts, he regards it as manifesting a relation of analogy to the order Cystica of Rudolphi. From all the genera of that order, however, it diff'ers in the want of the complex armature of the head, and of the dilated vesicle of the tail. At first sight it seems indicative of an annectant group which would complete the circular arrangement of the Entozoa by combining the form of the Filari(B of the first, with some of the characteristics of the Cysticerci of the last, of Rudolphi's orders. Unfortunately the class Entozoa, as it now stands, is so constituted that an animal may be referred to Entozoon infesting the Muscles of the Human Body, 455 it without much real or available knowledge of its organization being thereby afforded : it embraces animala with the molecular, and others with the filiform, condition of the nervous system; conditions which are accompanied by different types of the digestive system, and which in- dicate not merely differences of class, but even of primary division, in the animal kingdom. Mr. Owen considers the animal under consider- ation as being most nearly allied to that form of the Poly gastric In- fusoria which is exhibited by the lower organized Vibriones of Miiller, and of which Ehrenberg has composed his genera Vibrio, Spirillum^ and Bacterium; and that, like the seminal Cercaria, it may be regarded as an example from the lowest class of the animal kingdom having its habitat in the interior of living animal bodies. Referring it, however, provisionally, to the class Entozoa, in which it would indicate a new order, its generic character may be thus given : Trichina. Animal pellucidum, filiforme, teres, postice attenuatum : ore lineari, ano discreto nullo, tubo intestinali genitalibusque inconspicuis. (In vesici externa cellulos£i, elastic^, plerumque solitarium.) Trichina spiralis. Trich. minutissima, spiraliter, rarb flexuos^, incurva; capite obtuso, collo nullo, caudd attenuatd obtusd. (Vesicd externd ellipticd, extremitatibus plerumque attenuatis elongatis.) Hab. in hominis musculis (prseter involuntarios) per totum corpus diffusa, creberrima. Mr. Owen further states that within about a fortnight of the former case, a second body similarly affected had been brought into the dis- secting-room of Saint Bartholomew's Hospital ; and some notes were furnished by Mr. Paget, who first observed the worms in the Italian, with regard to the cases of the two patients while living in the Ho- spital. From these it appeared that both had died after long and de- bilitating illness, producing great emaciation, unaccompanied, how- ever, with any eruption on the skin, or any greater loss of muscular power than would probably have arisen from the diseases of which they died. The occurrence of two cases in the same dissecting- room within so short a period of each other, and the recollection of similar appearances being not unfrequently present in other bodies dissected there, combined with an account published in the Medical Gazette for February 2, 1833, of very small Cysticerci occurring in the muscles of a subject at Guy's Hospital, which cannot but be con- sidered referrible to the same cause, render it highly probable that a sufficient number of observations will soon occur to elucidate this curious disease. In two of the cases the emaciation was accompa- nied by external, and in the third by internal, ulceration ; but no connexion was traced between the worm and any of the symptoms of the disease. In a portion of muscle placed, after it had reached a state of inci- pient putrescence, in spirit of wine for three days, the worms, when pressed out from their cysts, exhibited languid, but sufficiently evi- dent motions, consisting in the tightening and relaxation of their coils : and more languid motions were afterwards noticed in some specimens that were examined a fortnight after the death of the sub- ject from which they were obtained. ^t56 Zoological Society : Mr. Owen o?i the Mr. Owen enters at some length into the question of the origin of the cyst, and after comparing its structure and connexions with -various more or less analogous productions, he states his opinion that the cyst is adventitious, foreign to the Entozoon, and composed of the .cellular substance of the body infested, morbidly altered by the irri- tation of the worm. The reading of the paper was accompanied by the exhibition of drawings showing portions of the infested muscle, with magnified representations of the cysts and of the worms contained within them ; and specimens of the objects themselves were also placed upon the •table for examination with the aid of Mr. Pritchard's microscope, lent by him for that purpose. Mr. Owen also read a Paper " On the Anatomy of Linguatula Tcenioides, Cuv." After referring to the observations on the anato- mical structure of this highly organized Entozoon, published by Cu- yier and Rudolphi, he proceeds to state the results of his own dis- section of a fine specimen, 3-^ inches in length, for which he was in- debted to Mr. LangstafF. The whole body is invested with a smooth, transparent, rather fine cuticle, which, from maceration, and proba- bly slight decomposition, had become detached. In this epidermis there exist no marks of an annulate structure ; but the cutis, or mus- cular parietes of the body, is distinctly divided into segments slightly overlapping each other, and most obvious on the sides of the body, which are its thickest and most muscular portions. The dorsal and ventral parietes, on the contrary, are so transparent as to allow of the contained parts being readily seen through them. The most essential difference between Linguatula and the Cestoidea, among which it was first placed by Chabert, consists in the genera- tive organs being androgynous, with the oviduct continued from one end of the body to the other. Rudolphi, uncertain with regard to the structure of the digestive organs, placed it among the Trema- toda ; but the specimen under examination affords conclusive evi- dence of the justice of Cuvier's removal of it to the Nematoidea. The alimentary canal commences at the central foramen, or true mouth, and runs straight to the opposite extremity of the body, terminat- ing immediately above the orifice of the genital tube ; the (esophagus being -5-rd of a line in length, and opening into a suddenly dilated canal, which continues with little variation of diameter to the anus. . At the distance of a line posterior to the mouth, on the ventral aspect of the body, the narrow extremities of two elongated vesicles, 3 lines in length and more than 4- a line in diameter, adhere firmly to the integument, the remainder hanging freely in the abdominal cavity. These Mr. Owen considers to be analogous to the impreg- nating glands of the hermaphrodite Rotifera, &c. The ovary, which is distinct from the tube so called by Cuvier and Rudolphi, is a nar- row, elongated, minutely granulated body, extending along the me- sial line of the dorsal parietes of the body for the extent of its two anterior thirds : about -f an inch from the head it gives off two slen- der capillary tubes, which unite below the origins of the lateral nerves, and enter the commencement of the oviduct. The com- mencement of this tube, formed by the junction of the two ducts Comparative Osteology of the Orang Utuji and Chimpanzee. 457 just mentioned with those of the seminal vesicles, is very narrow : in the greater part of its course it is coiled in numerous and complex gyrations around the intestine, but towards the lower third of the body its coils become fewer and more distant, the brown ova are seen in scattered masses, and at length it runs parallel with the in- testine straight to the anus. It is widest at the commencement of the coils ; then becomes narrower ; and afterwards continues of the same diameter to its termination. The cerebral ganglion mentioned by Cuvier was very conspicuous in the specimen here described : it is situated between the mouth and the commencement of the oviduct, and is consequently sub- oesopha- geal. Eight pairs of nerves may be distinguished going from it in a radiated manner. ITiis radiated disposition of the nervous system is similar to that which obtains in the Slug (Limax) ; and it may also be observed that the disposition of the muscular system in Limax is analogous to that of Linguatula, being most developed at the sides of the foot, and least along the middle line, which is thin and semi- transparent when viewed against the light. If it were allowable to trace further the analogy of form subsisting between genera so widely separated, the two fossa with their little hooks on either side the mouth of Linguatula, might be compared with the two depressions, which, when the tentacula are retracted, may be seen in the same situation in the head of the Slug, It is the superior organization of these parts, required for its superior powers of locomotion, that ren- ders necessary the further development of the nervous system in the Slug ; and the completion of the cerebral ring and the development of the supra- oesophageal ganglia constitute the chief difference be- tween it and Linguatula in this part of their organization. In like manner the action of the muscles in the Slug occasions waste, and demands a proportionate supply of new material ; and hence the ne- cessity of the superaddition of a sanguineous system for the car- riage of the restorative molecules, of a more complex digestive appa- ratus for their supply, and of respiratory and secretory organs for the elimination of the waste parts of the body. In Linguatula, on the contrary, the sphere of action being limited to a dark cavity, the necessity for the superadded structures does not exist ; its food, sJ- ready animalized, requires only a simple canal to complete its assi- milation ; neither heart nor vessels are conspicuous ; and it is pro- bable that nutrition is effected by transudation and imbibition. The reading of Mr. Owen's Paper was accompanied by the exhi- bition of drawings in illustration of the structures described in it, March 10th. — Mr. Owen commenced the reading of a Paper " On the comparative Osteology of the Orang and Chimpanzee.** He stated that he was indebted to Mr. Walker for the opportunity of examiiiing and describing in detail the skeleton of an adult Chimpanzee^ ob- tained by that gentleman a few years since from the west coast of Africa, which had enabled him to compare it with that of the young animal. This comparison evidenced in that species a series of changes in the advance towards maturity, analogous to those which take place in the Orang and the Pongo, nnd consequently afforded a strong Third Series. Vol. 6. No. 36. June 1835. 3 N 458 Zoological Society : Mr. Owen on the confirmation of the opinion which regards the latter animal as the adult of the former. The general ap}>earance and proportion of the Chimpanzee, Mr. Owen remarks, are unquestionably the most anthropoid that the Quadrumanous order presents; but many marked and essential differences are observable upon a close comparison. The skull of the adult is of a narrow elongated ovate figure, slightly contracting towards the anterior part, which is, as it were, truncated, from the depth and direction of the symphysis of the lower jaw. Compared with the rest of the body it is of small size, owing to the arrested development of the cerebral portion, which, as in other Quadrumanay is altogether posterior, the face sloping forwards in the adult ani- mal, at an open angle, as in the Baboons. Its exterior surface is devoid of the intermuscular frontal and sagittal crests which give so strong a carnivorous character to the skull of the Orang. The extent of the origin of the temporal muscles is, however, readily traceable by a slightly elevated ridge of bone : it differs considerably in the adult and in the foetal skulls, but exactly accords with the in- crease in the power of mastication required for the due action of the large permanent teeth. It is possible that the slight development of the intermuscular crest may be a sexual character ; for in an adult female cranium of the Orang, the crest was scarcely more prominent than in the Chimpanzee : in the latter, however, its development is less to be expected, in consequence of the smaller comparative size of the canine teeth. The muscular impressions on the occipital re- gion are also less strongly marked than in the Orang, in which the occiipkal foramen is nearer the posterior plane and its position is more oblique. There is a greater proportion of brain behind the meatus auditorius externus in the Chimpanzee than in the Orang, and this disproportion is much greater in the adult than in the young. Considerable changes also take place in the relations of the meatus auditorius with the glenoid cavity for the articulation of the lower jaw, in consequence of the increased development of the maxillary apparatus, while the cranium remains nearly stationary; and a pro- cess, of which the rudiment is perceptible in the young animal, co- extending in downward growth vvith the changed position of the articulation, becomes interposed between the condyle and the meatus, and affords a support against backward dislocation. In the cranium of the negro, a similar process may be traced in a rudimental con- dition, anterior to the Jissura Glaseri, as in the young Chimpanzee, The zygoma is proportionally weaker than in the Orang. But the most remarkable characteristic of the skull of the Chimpanzee, both in the young and adult states, is the large projecting supra^ orbital ridges, which being continued into each other across the glabella, form a sort of barrier between the head and face. The cranial sutures, which are obliterated in the adult Orang, syndaC' tylous Ape, and more or less in the Baboons, are for the most part persistent in the Chimpanzee, as in the human subject. Enough of the squamous suture remains to show that the anterior angle of the Comparative Osteology of the Orang Utan and Chimpanzee, 459 temporal bone joins tlie frontal, and separates the parietal and sphe- noid bones, as in the young. The condyloid processes are propor- tionately smaller than in the human subject, and their articular sur- face is directed more outwardly. The foramen magnum is thrown back to about the middle of the posterior third of the base of the skull, and its plane is inclined from before upwards at an angle of 5°. There are no posterior condyloid/orarwina. The styloid process is re- presented by a very small tuberosity. A considerable space inter- venes between the foramen magnum and the bony palate, which it- self equally exceeds the corresponding portion of the human skull. The zygomatic arches are opposite to the middle third of the cranium as seen from below, in which position also the contraction of the skull between the zygomata offers a marked distinction from that of Man, In the front view of the cranium, the threatening supraciliary ridges almost hide the cephalic cavity from view; and the latter, instead of forming a broad back-ground to the face, as in the young Chimpan- zee, and still more in Man, is surpassed in breadth by the lateral boundaries of the orbits and the zygomatic arches. The orbits are seated higher than in the Orang, and are larger in proportion; but their plane is more perpendicular, and they are wider apart. In neither the Chimpanzee nor the Orang is there a supraorbitary foramen, but its place is marked by a slight groove. The lachrymal bones are entirely confined to the orbit. A character by which the Chimpanzee approximates more closely than the Orang to the human subject is found in the nasal bone, which projects in a slightly arched form beyond the interorbital plane, and exhibits at its lower margin a trace of its original separation into two lateral portions : it is an- chylosed with the osfrontis and the suture obliterated. The malar bones are largely developed, and two or three sma\\ foramina are observable in the process on the outside of the orbit. The contour of the upper jaw from the nasal aperture to the incisor teeth is almost straight, while in the Orang it is rendered concave by the greater development of the alveolar processes of the intermaxillary bones. The obliteration of the sutures between these bones and the upper maxillary takes place at a much earlier period in the Chimpanzee than in the Orang ; although in the young animal, when the first dentition is complete, traces of the original separation are still visible. The situation o^ the foramina incisiva is always indicative of the original extent of these bones, and in no Mammal do they approximate so closely to the incisive teeth as in Man, The infra- orbitary canal opens upon the face by a sxn^e foramen : Mr. Owen has observed a second in one young specimen, but never more. In the Orang there are usually three or more, as in many of the inferior Simice. The lower jaw, like the upper, is characterized by its strength and relative size. Its symphijsis recedes, but the depth at this part is much less than in the Orang. The alveoli advance more nearly to the level of the condyle, and consequently approximate propor- tionally to the structure of the brute; the menVdl foramen is single. Mr. Owen next proceeds to notice the denial formula and the 3 N 2 460 Zoological Society I'btlv.Ovfex^ on the characters of the teeth; and observes particularly on the modifica- tions in their arrangement and relative position consequent on the preponderating development of the cuspidatus. He also points out the more important deviations which occur in the disposition and development of the different bones of the face in conuv xion with the same influential condition of the organs of mastication ; and then continues his description of the skeleton of the Chimpanzee by pass- ing to that of the trunk. The number of the veriehrce is the same as in Man ; but an addi- tional rib subtracts one from the lumbar to be added to the dorsal series. The spines of the cervical vertehrce are simple and elon- gated; that of the third being the shortest, with the exception of the ailas^ which, as usual, is without spine. The bodies of the lum- bar vertehrcB are proportionally smaller than in Man ; a difference easily accounted for by the necessity of affording a basis for the support of the latter in the erect position ; and the same recession, from the Bimanous type is manifested in the narrow and elongated form of the sacrum. In the adult animal, but less conspicuously in the young, the iliac bones rise on either side of the last lumbar ver- tebra, and are partially attached to it. The coccygeal are anchy- losed together, but not with the sacrum ; three are distinctly visible in the young. Of the sacral vertehrce only the two superior are united to the iliac bones. The pelvis differs from that of Man in all those particulars which characterize the Quadrumana, and which re- late to the imperfection of their means of maintaining the erect posi- tion. The iliac bones are long, flat, and narrow, the anterior sur- face stretching outwards almost parallel with the plane of the sacrum; the aperture is elongated and narrow ; and the tuberosities of the ischia are broad, thick, and curved outwards. There is, however, a provision for a more extended attachment of the glutcei muscles in a greater breadth of the ilia between the superior spinous processes than is observed in the inferior Simice; and we may thence infer that the semi-erect position is more easily maintained in the Chim- j^anzee. In the relative size and strength of the lower extremities, the Chim- panzee claims a much closer relationship to the human subject than the Orang. Both animals exhibit in this respect permanent condi- tions that are transitory in Man', in the Orang the legs have the cur- tailed proportions which they present in the human fcetus of four months' gestation ; in the Chimpanzee they retain the relative size of the yearling infant. The femur, not more bent anteriorly than in Man, has its neck of equal comparative length, but standing out more obliquely from the shaft. In the adult as well as in the young Chimpanzee, the depression in the head of the/crwMr for the attach- ment of the ligamentum teres, which is wanting in the Orang and the Pongo, is found to exist, notwithstanding the remark of Meckel to the contrary. The tibia andjibula are proportionally thicker and stronger than in Man ; and the patella proportionally smaller. In their relative size and position the tarsal bones more closely resemble the corresponding bones of the human subject than those of any other Comparative Osteology of the Orang Ulan and Chimpanzee, 461 Quadrumanous animal. The outer articulating surface of the astra^ galas is, however, of larger size, and a corresponding disproportion exists between the external and internal malleolus, the latter, from its smaller size, presenting less resistance to the rotation of the tarsus inwards. The os calcis projects further backwards than in the lower Simice, but is more compressed laterally, and of much smaller pro- portional size than in Man. The os naviculare projects further down- wards, and the internal cuneiform bone has a corresponding inclina- tion below the level of the tarsal bones. But whilst the Chimpanzee exhibits the Quadrumanous characters in these particulars, and es- pecially in the curtailed proportion and detached opposable condi- tion of the hallux, it approaches more nearly to Man in the length and strength of that member. The whole foot is much longer than in the human subject; and the entire organization of the inferior members evidently bespeaks a creature destined to reside in forests^ the modifications of the bony structure which add to the facility of climbing and grasping, rendering the entire frame more dependent on the upper extremities for the means of progression and support. The size and expansion of the thorax is a marked character in the Chimpanzee : it has thirteen ribs on each side, and the last two pairs are proportionally longer than in Man, the end of the last not being pointed, but widened for the attachment of a cartilage. The sternum is flattened, but not so broad as in the Orang. The har^ monia between its body and the manubrium, and those between the four single pieces of which the body is itself composed, remain visi- ble in the adult skeleton. The clavicle is long and strong, and is not straight, as in the Orang, but sigmoidally curved, though in a less degree than in Man ; while the scapula, on the other hand, re- cedes further from the human type than in the Orang. The hume- rus very closely resembles that of the human subject, but is propor- tionally longer and stronger, and has its twist more strongly marked and lower down on the bone. As the segments of the limbs recede further from the trunk they become subject to greater and more varied modifications. Thus the disproportionate length of the hu- merus is succeded by a still greater elongation of the fore-arm, the bones of which are also more curved from each other than in Man, and the inter-osseous space consequently enlarged. The bones of the carpus are the same in number as in the human subject ; but the trapezium and trapezoides are proportionally smaller, while the os pisiforme nearly equals the os magnum. The thumb does not quite equal in length the metacarpal bone of the first finger, and is as slender and weak as it is short. Some little disproportion also exists between the relative lengths of the fingers; but taken together they are relatively stronger and more elongated than in Man. After completing his detailed examination of the skeleton, Mr. Owen reverts to the changes which it undergoes in its progress to maturity, especially as regards the proportions of the head and face ; and states that he has derived full confirmation of the identity of species in the young and adult crania, from a comparison of the crowns of the permanent teeth lodged within the jaws of the young 4^62 Zoological Societi/: Mr. Owen on the Chimpanzee with those which had replaced the deciduous teeth in the older specimen. The resemblance in point of size and figure was exact, and left no room for doubt as to the point in question. The succession takes place precisely as in the human subject, but the per- manent teeth, and especially the incisors and canines, are proportion- ally longer. The particulars of their form and arrangement are given at length. This portion of the paper was accompanied by an extensive series of admeasurements of the different parts of the skeleton in the adult and young Chimpanzee, compared with those of the young and adult Orang; and was further illustrated by numerous drawings, and by the exhibition of Mr. Walker's skeleton of the Chimpanzee^ lent by him for the purpose. The second portion of the paper commences with the remark that the opportunity which the rare and interesting skeleton of the adult Chimpanzee, in the possession of Mr. Walker, had afforded of tracing the changes of structure occurring in that Ape^ in its progress to the adult condition, had induced the author to review the question relative to the identity of the young Simia Satyrus with the great Pongo of Borneo, formerly brought by him under the notice of the Society (Phil. Mag. and Annals, N.S., vol. ix, p. 60,) and to consider the osteological structure of the latter, or adult Orang, with reference to that of its less powerful and more anthropoid congener, the Chim- panzee. This comparison would show that the number and value of the points of resemblance, or of approximation, to the Bimanous structure are in favour of the Chimpanzee ; although in this, as in most other instances, there are some particulars of its organiza- tion indicative of a more marked relation with the inferior forms of the group than with those which rank immediately below it*. In common with the skull of the Mandrill that of the adult Orang is remarkable for its flattened occiput^ formidable canine teeth, huge jaws, widely expanded zygomatic arches, .and strongly developed cranial ridges; but it exhibits a marked distinction in its less brutalized expression, resulting from the more perpendicular slope of the face, the absence of the projecting supraciliary ridges, the greater expan- sion of the cerebral cavity, and the non-development of the supra- maxillary ridges. Its cranium is less flattened at the vertex than that of the Chimpanzee; and but little exceeds in capacity that of the young at the period of acquiring its first permanent molares, the increase in size being chiefly dependent on the thickening of the walls of the skull. The ridges which circumscribe on the frontal bone the origin of the temporal muscles inclose a triangular space, the smoothness of which strongly contrasts with the irregular surface of the re- mainder of the cranium ; and the interparietal crest rises, as in the Hycena and other Carnivora, high above the general level. The situation of these ridges, with reference to the sutures, is only de- terminable by comparing the faint commencement of their growth in the young animal, very few traces of the sutures remaining in the • Do not these facts indicate the existence of a tendency towards a cir- 'cular succession of affinities in the group formed by the Simicv ? — E. W. B. Comimrativc Osteology of the Oiang Utan and Chimpanzee* 463 adult skull. That between the ala of the sphenoid bone and the descending angle of the parietal, by means of which the frontal and temporal are kept separate, and which offers one of the few osteological differences in which the Orang has a closer approxima- tion to the human structure than the Chimpanzeej is among those which continue to be marked even in the adult. The occipitaiybra- men approaches in figure, position, and aspect, nearer to that of the lower Mammalia ; the occipital condyles are more closely ap- proximated anteriorly; the anterior condyloid /orawm« are double on each side; and the carotid /oramew is situated more posteriorly, and is relatively smaller, than in the Chimjjanzee. The petrous portion of the temporal bone is smaller, while the glenoid cavity forms a much larger proportion of the base of the skull. This cavity, if such it may be called, presents a quadrate, almost flattened sur- face, slightly concave in the transverse, and slightly convex in the antero-posterior direction, affording an interesting correspondence with the structure of tlie molar teeth, and indicative of the vegetable diet of the animal. The styloid and styliform processes are want- ing, as in the Chimpanzee ; the mastoid is represented by a protube- rant ridge, and its cellular structure is visible in consequence of the thinness of the external table. The ant-auditory process is more developed than in the Chimpanzee^ and the margins of the auditory foramina are smoother. On the bony palate, the relative positions of \he foramina inci&iva correspond with the increased development of the laniary teeth, and consequently deviate in a proportionate degree from their positions in the Chimpanzee and in the human subject. Two or three fora- mina remain on either side and indicate the original separation of the incisive bones ; and similar indications of the original harmonice between the incisive and maxillary bones are seen on the anterior part of the skull. In the Chimpanzee the obliteration of these sutures takes place some time before the temporary teeth are shed ; in the Orang they remain until the permanent teeth are almost fully deve- loped : in the human subject the intermaxillary bones can be traced as distinct elements only in the early periods of fcetal existence, when they were first detected by the poet Goethe. In the Orang no part of the OS nasi projects, as in the Chimpanzee^ beyond the plane of the nasal processes of the superior maxillary bones ; and there are no traces of its original separation at the mesial line, while in the Chimjmnzee such traces are usually found, and Dr. Traill observed two distinct ossa nasi in the young of that species dissected by him. The lachrymal bones are proportionally larger than in Man ; but, as in the Chimpanzee and the higher Quadrumanaf they are confined to the orbit^ the whole outer boundary of which has a more anterior aspect than in the Chimpanzee^ and is relatively broader and stronger, but with the oblique posterior edge less developed. The interorbi- tal space is relatively narrower, the disproportion increasing with the development of the superior maxillary bones, and evidencing a still further departure from the human form. There are three infra- orbital/oramina instead of one ; the upper maxillary bones are much 464? Zoological Society : Mr. Owen on the more largely developed in consequence of the great size of the laniary teeth ; and the incisor teeth project more obliquely forwards than in tlie Chimpanzee. *' In all the peculiarities," Mr. Owen observes, " of the Orang's skull, which are independent of the changes consequent on the se- cond dentition, we find an exact correspondence between the Simia Satyrus, or young animal, and the Pongo, or adult. The crania equally exhibit the absence of the projecting supraciHary ridges ; the presence of the double anterior condyloid foramina ; the numerous infra- orbitary /omwma, and those in the malar bone ; the same disposi- tion of the cranial sutures ; the same form of the os nasi; and con- traction of the inter-orbital space. The character of the lower jaw by which it differs from the Chimpanzee, viz. the greater height and breadth of the rami, and the greater depth of the sym,physis, are equally manifested in the young as in the old Simia Satyrus. In followinor out the same observations with regard to the germs of the permanent teeth in the young Orang, the same satisfactory results are obtained in reference to their identity with those which are fully developed in the old animals, as were previously detailed in the ac- count of the Chimpanzee," Mr. Owen then proceeds to describe in detail the appearances presented by the germs of the permanent teeth, and to compare them with the adult; and concludes this part of his subject by some ob- servations on the apparent confusion in which these germs lie hid- den within the jaw, and on the admirable and orderly arrangement by which the most perfect regularity is established in their ultimate position. Applying these observations to the replacement of the teeth in man, he inquires, how it happens that when the chances of disarrangement are so much fewer, the mal-position of the perma- nent teeth is of so frequent occurrence, and finds the solution of this problem in a mischievous interference with the agents to which the necessary changes have been entrusted. "The means by which the growth of the permanent teeth are kept in due restraint are too often prematurely removed by anticipating the natural period of the extraction of the temporary teeth; the act of extraction accelerates the growth of the concealed teeth, both by the removal of the check which nature has imposed upon it, and by the irritation induced in the surrounding parts: and their full development being consequent- ly acquired before the jaws have been sufficiently enlarged, they occupy more or less of the relative position which they had when half formed within their bony cavities." The conditions of the superior development of the spinous pro- cesses of the cervical vertehrce in the Orang, are obviously the back- ward position of the occipital /oramen, the disproportionate develop- ment of the face, and the general anterior inclination of the vertehrce themselves. Those of the sixth and seventh vertebrce have a slight inclination towards the head, indicating that the centre of motion in this region is nearer the head than in Man. I'he whole of the cer- vical region is proportionally shorter, and consequently better adapted to support the head ; and the entire vertebral column has one gene- Comparative Osteology of the Ora?ig Utan and Chimpajtzee, ^Q5 ral curve dorsad from the atlas to the commencement of the sacrum, where there is a slight curve in the contrary direction. As in Man, the number of the dorsal or costal verlehrce is twelve, and this con- stitutes one of the more important differences between the Orati'r and the Chimpanzee. That of the lumbar vertehrce is four, as in the Chimpanzee, in the skeleton of the Pongo preserved in the Museum of Comparative Anatomy at the Garden of Plants, and in the trunk of the skeleton of the adult Orang in the collection of the Society ; in which latter, as the bones remain connected by their natural liga- ments, there is no room for supposing a vertebra to have been acci- dentally lost. The additional lumbar vertebra in the skeleton of the Pongo in tlie College of Surgeons, on which some stress has been laid, as indicative of its specific difference from the young Orang, which has uniformly presented but four, indicates its abnormal cha- racter by its form and situation. The human subject occasionally presents a similar lusus in the addition of a sixth lumbar vertebra. The spines of these vertebrce are much shorter than in the Chim- panzee: as in the latter, the sacrum is longer, narrower and straighter than that of Man. Five sacral vertebrce are perforated for the passage of the spinal cord ; three are imperforated, and are conse- quently coccygeal : the latter are anchylosed together, but not with the sacrum, in the adult. The ilia are as much expanded as in the Chimpanzee, but flatter ; and the ischia are less extended outwards, corresponding with the smaller development of the lower extremities. Both the ischia and ossa pubis resemble those of the Chimpanzee, in their more elongated form ; and the whole pelvis equally deviates from the Bimanous type in its position with regard to the trunk. The form of its superior aper- ture is an almost perfect oval, the antero-posterior diameter of which is to the transverse as three to two ; and the axis of the brim forms, with that of the outlet, a much more open angle tlian in the human subject. The chest is amply developed, equalling in size that of the human subject, except in being somewhat narrower from side to side. The ribs are narrower and less flattened, but their curvature is nearly the same as in Man ; the twelfth is much longer, and has a long cartilage at its free extremity. The sternum is short, but broader than in the Chimpanzee: it is composed, below the manu- brium, of a double series of small bones, seven or eight in number. This composition, always seen in the young Orang, is sufficiently obvious in the adult Pongo in the Museum of the College of Sur- geons, but much less so in that of the Garden of Plants at Paris. In the young Chimpanzee ihe sternum is composed of a single series of bones; while in the human subject, although at an early period of ossification, a single series only of ossific centres appears : at a later stage the lower part of the sternum is frequently seen to be composed of a double series. The clavicles are almost straight; and the scapula also differs from that of the Chimpanzee in its greater breadth, and from that of Man in the inclination of its spine towards the superior costa, in thcacn- Third Series. Vol. 6. No. 36. June 1835. 3 O 466 Zoological Society : — Mr. Owen on the mion being narrow and claviform, and in the absence of the flattened and over-hanging margin of the spine. Other differences exist in the comparative dimensions and features of the supra- and s\xh» spinal /o55£^, in the inclination of the coracoid process, and in the direction of the glenoid cavity. But the principal feature in the organization of the Orang, and that in which it differs most from the Chimpanzee, consists in the relative length of the upper and lower extremities, the arms in the former reaching to the heel. The articular surface of the head of the humerus forms a complete hemi- sphere ; and in some specimens that bone is perforated between the condyles. The principal peculiarities in the fore-arm consist in the large space between the radius and ulna, occasioned by the outward curve of the former, and in the absence of the acute margin on its ulnar aspect. The proportion borne by the radius to the ulna is in Man as 11 to 12; in the Orang as 36 to 37. The bones of the hand offer the same elongated form, with the exception of those of the thumb, which does not reach to the end of the metacarpal bone of the fore-finger. Those of the carpushave their ossification com- pleted at a later period than in Man, and allow a freer motion upon each other : the os pisiforme is divided into two. Of the fingers, the proximal phalanges are more curved than in Man, and the dis- tal more pointed, not expanding to afford support for an extended surface of delicate touch. As the upper extremity of the Orawg exceeds in length that of the Chimpanzee, so the lower differs as much in the contrary respect; preserving throughout life much less than the foetal proportions of the human subject. The femur has a straight shaft, no depression on the head, a shorter neck forming a more obtuse angle with the shaft, and no linea aspera posteriorly. The inner condyle not being produced beyond the outer, the axis of the femur is in the same line with that of the tibia, as in the Chimpanzee. The inward curve of the tibia occasions a much larger space between it and the fbula than in Man or in the Chimpanzee. The patella is smaller in pro- portion than in Man, of an oval shape, and with a single articulating surface. The bones of the tarsus are numerically the same with those of the Chimpanzee, and have the same general form, but ad- mit of freer motion on each other. A greater degree of obliquity in the articulating surface of the astragalus causes the whole foot to be turned more inwards; and theo5c«/mhas still less projection back- wards than the Chimpanzee. The internal cuneiform bone recedes most from the human type in having a greater development towards the tibial aspect, and in having the surface of articulation for the hallux below the range of the other metatarsal bones, all of which are much longer and more bent and have greater interspaces than the human. That of the hallux extends very little beyond the mid- dle of that of the second toe, and stands off from it at an acute angle. The peculiarity of the structure of the hallux first noticed by Camper, in seven out of eight Orangs observed by him, viz. its possessing no vLn*^wedi\ phalanx and consequently no nail, loses much of its im- Comparative Osteology of the Orang Utan and Chimpanzee, 467 portance as a specific character from the fact that the individual dissected at the Society's Museum a few years since had very per- fect, but small, black nails, and two phalanges, and that the same number o^ phalanges exist in the natural skeleton of Lord Amherst's Orang in the Museum of the College of Surgeons. The phalanges of the other toes are remarkably elongated, and those of the first series are curved. The middle toe is longer than the rest, while in the Chimpanzee it barely surpasses the second. The concavity of the great toe is turned more towards the other toes than in the Chim- jmnzee, (in which that toe is also longer, having always two phalan- ges in addition to the metatarsal bone,) is set more forwards on the internal cuneiform bone, and has its concavity directed more towards the sole of the foot. The resemblance to the human foot is conse- quently greater in the Chimpanzee than in the Orang. In conclusion Mr. Owen adverted to a fine specimen of the skull of a Pongo in the possession of Mr. Cross, of the Surrey Zoological Gardens, which presents the following differences when compared with the skull of the Pongo in the Museum of the College of Sur- geons. It is shorter in the antero-posterior diameter, and rises higher at the vertex. The supraorbitary ridges are more prominent; the plane of the orbits is more vertical, and their lateral exceeds their perpendicular diameter. The profile line of the skull is concave between the glabella and incisor teeth, while, in the specimen in the Museum of the College, it is almost a straight line between the same parts. The symphysis of the jaw from the interspace of the mesial incisors to the origin of the genio-hyoidei muscles, measures g-J- inches in Mr. Cross's specimen, but equals S^ inches in the Pongo in the College Museum. There is also a remarkable difference in the position of the zygomatic suture. In the Pongo of the College Mu- seum it commences at the distance of a quarter of an inch from the orbital process of the malar bone, and extends obliquely backwards to within H inch of the origin of the zygomatic process of the tem- poral bone. In Mr. Cross's specimen the same suture commences 8 lines from the orbital process of the malar bone, and extends to within 10 lines of the origin of the temporal zygomatic process, so that it is much nearer the middle of the zygoma. With these differences, however, there exist the same form and proportions of the teeth, and the same peculiarities oi the foramina and sutures which distinguish the Orang from the Chimpanzee. So that although the difference in the shape and general contour of the two skulls, is greater than is usually observable in those of other wild animals, yet Mr. Owen does not consider them sufficient to af- ford grounds for a distinction of species. He thinks it, however, probable that they may be indicative of varieties of the Orang in- habiting distinct localities, and remarks that it would be interesting with that view to compare the crania of ascertained specimens from Borneo and Sumatra, to which Islands this very remarkable species appears to be confined. 302 S « rtiS s*^ s.s tS^ «sg .SP> OJ in i> • ^ «o S . ji j= «> J *J hcr-t >^'~'"5 00 •^■' I .S "^ ^ rt . M - ?^ >T3 ♦,» *-• § S j3 e •- c . . H i:i q5 3 . 1^ i! ■ !i ^/ r-t. r/^ M^4:^^ .SP, , to c o «o oj > rH 5 01 01 Ol •isog i'Ti'.ovoco 2*:: o • o 7" o ;;::::;;:;::::::::::: T" : : 6 * * * * •puoq . . -rfC^ . . . . • . o o : : : : :^ :S •jsog •puoq )soa I I i -• ^ « g ^ ^ ^' ^* 5:* g i i I i^ i£ >£ ^- ;£ i ^* ^- ii ^ i i ^ ^ s ^ u^ vo e< ^ Tt(o ^ M otT 0000 6^6^c^ooooo666oooa^o66ooo6 r>J rM rj m r«^ rm <«a r>n lk and flint of Yorkshire, 313 ; on an out- lying basin of lias on the borders of Salop and Cheshire, and account of the lower lias between Gloucester and Worcester, 314; general view of the new red sandstone series, in the coimties of Salop, Stafford, Worces- ter, and Gloucester, 315; coal tracts in Salop, Worcestershire, and N. Gloucestershire, 376. Geometrical series, analytical theorems relating to, 196. Germination, influence of electricity in, 157. Gill (Thos.) on the fibres of flax and cotton, 231. Goat, wild, description of, 225. Gopher- wood of Scripture, on, 401. Gothic architecture, progress of, 395. Graham (Prof.) on water as a consti- tuent of salts, 327, 417. Gray (Mr.) on the animal of Argo- nauta, 385 ; on two new species of sturgeon, 386; on the type of a new genus nearly related to Bipes, 391. Griffin (D.) on an unusual affection of the eye, 281. Hall (Capt. B.) on the want of per- pendicularity of the standing pillars of the temple of Serapis, 313. Hall (Dr. M.), experiments in the de- capitated turtle, 71. Halley (Dr. E.), account of his astro- nomical observations, 221 ; some par- ticulars of his life, 306. Halley's comet, on the return of, 45. Hamilton (Prof.) on a general method in dynamics, 298. Heat, on the repulsive power of, 58, 415; on the refraction and polariza- tion of, 134, 205, 284, 366. Heat and light, on the production of by animals, 246. Henry (Dr. W. C.) on the action of me- tals in determining gaseous combina* tion, 354. Hodgson (B. H.) on the mammalia of Nepil, 150; on the wild goatand the wild sheep, 225. INDEX. 471 Horner ^L.) on the solid matter siis- pendea in the water of the Rhine,396. Horner (W. G.) on the signs of the trigonometrical lines, 86. Hydrocyanic acid, preparation of, 97. Hygrometer, wet-bulb, formula for in- ferring the dew-point from the, 182. Infinite series, slowly converging and diverging, on the summation of, 348. Insects, circulation of the blood in, 300 ; new Dipterous insects, 280, 447. Iron and copper, alloys of, 81. Iron, peroxide of, an antidote to arse- niousacid, 237. Ivory (J.), astronomical refractions, 142. J. B. on the attraction of an homoge- neous ellipsoid, 203. J. H. N. on the juice of Eschscholzia Califomica, 77. Johnson (G. H. S.), method of disco- vering the equations of caustics, 872. Johnson (Dr. H.) on a newly observed property in plants, 165. Johnston (J. F. W. ) on the dimorphism of baryto-calcite, 1. Keith ( Rev. P.), structure of ani mals, 4, 90; classification of vegetables, 379. LepisosteuSf their internal organization, 384. Leptoconchus^ description of, 224. Lialisy the type of a new genus nearly related to Bipes, 391. Light, undulatory theory of, 16, 107, 189, 262 ; on the dispersion of, 374. Light and heat, on the production of by animals, 246. lAmnoria terebrans, 55. Linnaean Society, 72, 220, 379. Lubbock (J. W.) on some elementary applications of Abel's theorem, 116; determination of the terms in the dis- turbing function of the fourth order, 142. Lyell (C.) on the proofs of a gradual rising of the land in Sweden, 297. Magilus antiquus, 224. Magnetism, terrestrial, geometrical re- searches concerning, 302. Magneto-electricity, new phaenomenon in, 169; magneto-electrical decom- position of water,428 ; Magneto-elec- trical machine, optical effects of, 427. Meeson (H. A.) on the detection of opium, 158. Metallic oxides, separation of, 234. Metals : — heated, vibration of, 85 ; elec- trical relations of, 300 ; action of in de- termining gaseous combination, 354. Meteorite, in Moravia, 159; in India, 398. Meteorological Table for Nov., 80; for Dec, 160; for Jan., 240; for Feb., 320 ; for Mar., 400 ; for Apr., 468. Meteorology, of Dukhun, 59 ;Vemarks on the year 1 834 at Carlisle,* 427. Miller (W. H.) on the forms of sul- phurct of nickel, &c., 104. Mineralogy : — Allan's Manual of, 53; mineralogical notices, 76; analysis of nadelerz, 77 ; new mineral, 133 ; ana- lyses of osmiridium and allanite, 238. Mitchell's (Prof.) method of preparing caibonic oxide. Dr. Gale on, 232. Mitchell (Dr. J.) on the chalk and flint of Yorkshire, 313. Monetary calculation, a decimal system of, 441. Morphia and quina, new test for, 158. Motion, transmitted, analytical deter- mination of the laws of, 267. Mount Etna, eruption in 1536, 299. Murchison (R. I.) on an outlying ba- sin of lias on the borders of Salop and Cheshire, with an account of the lower lias between Gloucester and Worcester, 314 ; general view of the new red sandstone series in the counties of Salop, Stafford, Worces- ter, and Gloucester, 315; on certain coal tracts in Salop, Worcestershire, and N. Gloucestershire, 376. Muriate of ammonia, its action on cer- tain sulphates, 235. Muriatic acid, on the immersion of cop. per in, 444. Mushet (D.) on the practicability of alloying iron and copper, 81 ; on the fusion and appearance of refined and unrefined copper, 324; on the im- mersion of copper in muriatic acid, as a test of its durability, 444. Nadelerz, analysis of, 77. Newport (G.) on the nervous system of the Sphinx ligustri, 55. Nickel, form of sulphuret of, 104. Nixon (J.) on the trigonometrical height of Ingleborough, 248, 429. Nycteribia, the genus, 392. Olbers (Dr.) on the approaching return of Halley's comet, 45. Opium, detection of, 158. Omithorhynchus paradoxus, the ova of, 60; natural history and habits of, 307. Osteology, human, 57 ; of the orang and chimpanzee, 457. Osmiridium, analysis of, 238. Otter, Irish, 229. Owen (Rich.) on the ova of the Omi- thorhynchus paradoxus, 60 ; descrip- tion of a recent Clavagella, 230 ; on a new species of Entozoon, 452; ana- tomy of Linguatula Tcenioides, 450 ; osteology of the orang and chimpan- zee, 457. Oxides : — carbonic, on Prof. Mitchell's method of preparing, 232 ; metallic, separation of, 234; of cadmium and of bismuth, separation of, 235. Peroxide of iron, as an antidote to ar-' seniousacid, 237. Persian Gulf, advance of land in, 401. Phillips (R.) on the quantity of water contained in crystallized barytea and strontia, 52. 472 INDEX. Plants, on a property in, analogous to the irritability of animals, 1 6.5. Polarization of heat, 134, 205, 284,366. Potassium, ferrocyanuret of, and dilute sulphuric acid, reaction of, 97. Powell (Prof.) on the undulatory theory of light, 16, 107, 189, 262; on the repulsive power of heat, 58 ; on the achromatism of the eye, 247 ; on the dispersion of light, 374. Read (S.) on a decimal systemof mone- tary calculation, 441. Rees (G. O.) on the presence of titanic acid in the blood, 201. Refraction, of heat, 134, 205, 284, 366 ; double, exhibited in the oxalate of chromium and potash, 305. Reviews : — Allan's Maniial of Mine- ralogy, 53; Parkes's Chemical Cate- chism (I3tii edit.) by Brayley, 214; the West of England Journal of Sci- ence and Literature, 293. Rhinoceros, 151. Rigaud (Prof.), life of Br. Halley, 306. Rogers (H. D.) on the geology of North America, 64. Royal Institution of Great Britain, 394. Royal Society, 55, 142, 297, 371 ; me- dals for 1836 and 1837, 75. Rudge (E. ) on the position of the South Magnetic Pole, 371. Salts: — insoluble, employment of in analysis, 79 ; deliquescent, preserva- tion of, 319 ; water as a constituent of, 327,417. Sheep, wild, description of, 226. Shells, 68, 149, 387. Ship-sheathing, immersion of copper in muriatic acid for, 444. Sound, on the production and propa- gation of, 25. Sphinx ligustri, nervous system of, 55, Spirit-lamp furnace, new^, 292. Strickland (H. E.), account of land and freshwater shells found with bones of land quadrupeds, 149. Strontia and barytes, hydrates of, 52, Strontia, carbonate of, discovered in the United States, 234. Sturgeon (W.) on an aurora borealis seen at Woolwich, 230 ; experiments in magneto-electricity, Mr. Watkins's observations on, 239. Sturgeon, new species of, 386. Sugar, its conversion into formic acid and ulmin, 399. Sulphates, action of muriate of ammo- nia on, ^35. Sulphur, detection of minute portions of, 399. Sulphuret of nickel, form of, 104. Sykes (Lt.-Col.) on the atmospheric tidesand meteorology of Dukhun^ftr^ PRINTED BY RICHARD Sipignathus Acus and Ti/phle, 383. Telescope, zenith, twenty- five feet, 37.3. Teredo navalis, 55. Thompson (J. V.) on the metamorpho- sis of the Cirripedes, 373. Thompson (W.) on the Teredo tinvalis and Limnoria terebrans, 55. Thomson (J.) on the fibres of cotton, 1 70. Tides, atmospheric, of Dukhun, 59. Titanic acid, its existence in Hessian crucibles, 113; in the blood, 201. Tonna (L.) on some curious facts re- specting vision, 409. Torpedo, observations on the, 57. Tortoises, 152, 229, 380. Tourmaline, polarization of heat by,205. 205. Trevelyan (A.) on the vibration of heated metals, 85 ; description of a new spirit-lamp furnace, 292. Trevelyan (W. C.) on fragments of gar- net in the millstone-grit, 76. Trigonometrical height of Inglebo- rough, 248, 429. Trigonometrical lines, the signs of, 86. Tyrrell (J.) on the blood in insects, 300. Ulmin and formic acid, conversion of sugar into, 399. Undulatory theory of light, 16, 107, 189, 262; queries respecting, 398. Ure (Dr.), analysis of the Moira brine spring, 58, Dr. Daubeny on, 321. Vegetables, classification of, 379. Vesuvius, its eruption in 1834, 374. Vibration of heated metals, 85. Viper, of the Somersetshire Downs, 15.3. Vision, some facts respecting, 409. Voice, human, cause of the grave and acute tones of, 372. Wollastonite and zurlite, 76. Water, decomposition of, 428 ; as a constituent of salts, .327, 417. Watkins (F.) on Mr. Sturgeon's expe- riments in magneto-electricity, 239. Westwood (J.O.) newDipterous insects, 280, 447; on the genus Ni/cteribia,'692. Wheatstone (Prof.), experiments to measure the velocity of electricity, and the duration of electric light, 61* Williams (Dr. C. J. B.) on the pro- duction and propagation of sound, 25. Williams (Rev. D.) on bones of ani- mals discovered in the calcareo-mag- nesian conglomerate, 149. Woods (J.) on the species of Fediu, 380. X. on the undulatory theory, 398. Young (Prof.) on the summation of slowly converging and diverging in- finite series, 348. Zoological Society, 68, 150, 223, 307, 380, 452. Zurlite and wollastonite, 76. 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