3 PROCEEDINGS OF THE ROYAL SOCIETY OF LONDON. From May 5, 1859, to November 22, 1860 inclusive. *fe VOL. X. LONDON: PRINTED BY TAYLOR AND FRANCIS, RED LION COURT, FLEET STREET. MDCCCLX. Q m L118 CONTENTS. VOL. X. Page Propositions upon Arithmetical Progressions. By F. Elefanti, Esq. 1 On the Electric Properties of Insulating or Non-conducting Bodies. By Professor Carlo Matteucci of Pisa 2 On the Synthesis of Acetic Acid. By J. A. Wanklyn, Esq 4 On the Resistance of Glass Globes and Cylinders to collapse from ex- ternal pressure, and on the Tensile and Compressive Strength of various kinds of Glass. By William Fairbairn, Esq., C.E., F.R.S., and T. Tate, Esq., F.R.A.S 6 On the Atomic Weight of Graphite. By B. C. Brodie, Esq., F.R.S., Pres. C.S., Professor of Chemistry in the University of Oxford . . 11 On the Alloys.— Part I. The Specific Gravity of Alloys. By A. Matthiessen, Ph.D 12 On the Anatomy of Victoria Regia.—Psxt II. By Arthur Henfrey, Esq., F.R.S., F.L.S. &c., Professor of Botany in King's College, London 14 On the Conductivity of Mercury and Amalgams. By F. Craee-Cal- vert, Esq., F.R.S., and R. Johnson, Esq 14 On the Intimate Structure, and the Distribution of the Blood- vessels, of the Human Lung. By A. T. H. Waters, Esq., Lecturer on Anatomy and Physiology, Liverpool 16 On certain Sensory Organs in Insects, hitherto undescribed. By J. Braxton Hicks, M.D. Lond., F.L.S. &c 25 On Lesions of the Nervous System producing Diabetes. By Frederick W. Pavy, M.D. Lond. &c 27 On the Electrical condition of the Egg of the Common Fowl. By John Davy, M.D., F.R.SS. L. & E. &c 31 On the Mode in which Sonorous Undulations are conducted from the Membrana Tympani to the Labyrinth, in the Human Ear. By Joseph Toynbee, Esq., F.R.S. &c 32 On the Electrical Discharge in vacua with an Extended Series of the Voltaic Battery. By John P. Gassiot, Esq., F.R.S 36 Note on the Transmission of Radiant Heat through Gaseous Bodies. By John Tyndall, Ph.D., F.R.S. &c 37 02 IV Page Photochemical Researches.— Part IV. By Robert W. Biinsen, For. Memb. R.S., and Henry Enfield Roscoe, Ph.D., Professor of Che- mistry in Owens College, Manchester 39 On the Occurrence of Flint-implements, associated with the Remains of Extinct Mammalia, in Undisturbed Beds of a late Geological Period. By Joseph Prestwich, Esq., F.R.S., F.G.S. &c 50 Observations on the Discovery in various Localities of the Remains of Human Art mixed with the Bones of Extinct Races of Animals. By Charles Babbage, Esq., M.A., F.R.S. &c 59 Remarks on Colour-blindness. By Sir John F. W. Herschel, Bart., F.R.S 72 On the Laws of Operation, and the Systematization of Mathematics. By Alexander J. Ellis, Esq., B.A., F.C.P.S 85 Annual General Meeting for the Election of Fellows 95 On the frequent occurrence of Vegetable Parasites in the Hard Struc- tures of Animals. By Professor A. W. Kolliker, of Wiirzburg 95 Researches on the Phosphorus-Bases. — No. VI. Phosphammonium- Compounds. By A. W. Hofmann, LL.D., F.R.S. &c 100 Notes of Researches on the Poly- Ammonias. — No. VI. New Deriva- tives of Phenylamine and Ethylamine. By A. W. Hofmann, LL.D., F.R.S. &c 104 On the Behaviour of the Aldehydes with Acids. By A. Geuther, Esq., and R. Cartmel, Esq 108 On the Action of Acids on Glycol (Second Notice). By Dr. Maxwell Simpson 114 Experiments on some of the Various Circumstances influencing Cu- taneous Absorption. By Augustus Waller, M.D., F.R.S., Professor of Physiology, Queen's' College, Birmingham 122 On Spontaneous Evaporation. By Benjamin Guy Babington, M.D., F.R.S. &c 127 On the Application of the Calculus of Probabilities to the results of measures of the Position and Distance of Double Stars. By the Lord Wrottesley, F.R.S. &c 133 Report of Scientific Researches made during the late Arctic Voyage of the Yacht *«) re«^ (*, *»). „ , „ „ 6, ditto ditto. „ „ 8, forh2 readhr „ „ 10, do. do. j, 55 14, do. do. Page 196, line 6 from bottom, for "Broadhurst" read "Brodhurst." Page 197, line 10 from top, for " occasionally weakens the muscle " read " may occasion weakness of the muscle." Page 324, line 2, for "portable" read "absolute." Page 327, line 18, after " disc," insert " when touching the metal below." Note to the Obituary Notice of Mr. Brunei, p. viii, Hne 16. The statement that Mr. Brunei designed the Bute Docks at Cardiff, although founded on what the writer had reason to consider good authority, has since been ascertained to be erroneous. PROCEEDINGS U OF THE ROYAL SOCIETY May 5, 1859. Sir BENJAMIN C. BRODIE, Bart., President, in the Chair. In accordance with the Statutes, the President read the following list of Candidates recommended by the Council for election into the Society : — Samuel Husbands Beckles, Esq. Frederick Grace Calvert, Esq. Henry J. Carter, Esq. Douglas Galton, Esq. William B. Herapath, M.D. George Murray Humphry, Esq. Thomas Sterry Hunt, Esq. John Denis Macdonald, Esq. William Odling, Esq. Robert Patterson, Esq. John Penn, Esq. Sir Robert Schomburgk. Thomas Watson, M.D. Bennet Woodcroft, Esq. Lieut.-Col. W. Yolland. The following communications were read : — I. " Propositions upon Arithmetical Progressions/' By F. ELE- FANTI, Esq. Communicated by ARTHUR CAYLEY, Esq. Received April 6, 1859. (Abstract.) The author sketches the investigation of the way of throwing various series of integer terms into arithmetical progressions, such as the sums of squares, cubes, &c. of figurate numbers, of the powers of a number, &c. He also gives the resolution of a given number, VOL. x. B in certain cases, into an arithmetical progression. Thus, having the theorem that N can be resolved into an arithmetical progression when 16 N+l is a square, he is enabled to detect factors in N ; he thus shows that 2079519603 has 43 and 101 among its factors. Among theorems which the method gives, may be noticed the following, as one of a peculiar and unstudied class. If in the series 1, 3, 5, 7, &c. four terms be taken, and the next one omitted, then the four next terms taken and the next three omitted, then four terms taken and/#6> omitted, and so on, the four terms taken will in every case consist of numbers prime to one another. II. Abstract of a Memoir "On the Electric Properties of Insulating or Non-conducting Bodies/' By Professor CARLO MATTEUCCI of Pisa. Communicated by Major- General SABINE, E.A., V.P. and Treas. R.S. Received April 14, 1859. The object of the author in the first part of this memoir is to ascertain by experiment what condition is assumed by insulating or non-conducting bodies in the presence of an electrified body, and in what degree such condition is developed in insulating bodies of different kinds. In a memoir published nearly ten years ago (Ann. de Chim. et de Phys., xxvii. p. 134), he had shown that a cylinder of gum-lac, sulphur, stearic acid, or the like, suspended by a filament of silk, and brought near to a body charged with electricity, begins to oscillate in the same way as a cylinder of metal. The non-con- ducting cylinder, whilst under the influence of induction, behaves like any body charged with opposite electricities, and returns to its natural state when the induction ceases. These experiments have now been very carefully repeated with cylinders formed of various insulating substances, made as nearly as possible of the same length and perfectly diselectrized. The air was rendered perfectly dry, and the inducing ball was charged with electricity to a constant degree, measured by the torsion-balance. After giving a numerical statement of the time of oscillation and the moment of the induced force, as determined by experiment for cylinders of different insulating substances, and after describing other 3 experiments intended to prove the insulating property of the ma- terials employed, the author goes on to observe that there is but one way of explaining the phenomena in question, namely, by supposing that the individual particles or molecules of the non-conducting cylinder acquire different electrical states at their opposite extremi- ties, and that these electrical states, while they are readily developed and neutralized within each particle, meet with great resistance in passing from one particle to another, — a condition of non-conducting bodies which constitutes the molecular electric polarization of Faraday. The author then gives the result of some experiments on the amount of electrical charge communicated to, or given out by an insulated conducting ball surrounded, at one time by air, at another time by an insulating substance, such as sulphur. In conclusion, the author thinks that the following propositions may be regarded as rigorously demonstrated by experiment : — 1 . The effects produced on insulating cylinders in the presence of an electrified body, depend on the state of molecular electric polarity which that body developes in the cylinders ; and thus the hypothesis of Faraday is directly demonstrated by experiment. 2. Other circumstances being alike, the insulating power of a substance is greater in proportion as its degree of polarization is weaker. 3. The electric capacity of a conducting body — that is, the quan- tity of electricity which it acquires when placed in communication with a source of electricity — is much greater when the body is surrounded with sulphur, or some other solid isolating substance, than when surrounded by air. Similarly, the body being electrified from the same source and then surrounded with sulphur, or else surrounded with air, afterwards yields to the same conductor much less electricity in the former case than in the latter. 4. The effects produced by insulating plates interposed between the armatures of a Leyden jar or of a magic square are explained, together with the phenomena previously described, both by the penetration of the electricity into the interior of the insulating sub- stance, and the propagation of electricity along the surface of the plates. III. " On the Synthesis of Acetic Acid." By J. A. WANKLYN, Esq. Communicated by Dr. E. FRANKLAND. Received April 27, 1859. I have elsewhere* shown that a salt of propionic acid results when carbonic acid is brought into contact with a compound consist- ing of ethyl and an alkali-metal. Guided by a well-known principle, I also inferred that an analogous reaction is common to the whole vinic series. Believing, however, that it was desirable to investigate other mem- bers of the series, I have since undertaken the case of the corre- sponding methyl-compound, and find that it fully bears out the law, as will be manifest from the following details. Some sodium-methyl in mixture with zinc-methyl, zinc, sodium, and ether was obtained by acting with sodium upon a strong ethereal solution of zinc-methyl. The product so obtained was divided into two portions — one of which was exposed to the action of a current of dry carbonic acid, and the other reserved for comparison. During the transmission of carbonic acid, the sodium-methyl became hot. After the completion of the reaction, the resulting solid was treated with a little mercury, in order to convert any free sodium into an amalgam, which would not decompose water with too great violence. Subsequent distillation of the product, with excess of dilute sul- phuric acid, yielded a distillate having most distinctly the smell and taste of acetic acid. This acid distillate was redistilled, when it proved to be free from sulphuric acid. Some of it was converted into a silver-salt by digestion with oxide of silver. This silver-salt was dissolved in hot water, filtered hot, and allowed to crystallize on cooling. An abundant crop of crystals separated, which was drained from the mother-liquor, the employ- ment of a filter being avoided. The crystals were afterwards dried in vacuo over sulphuric acid until they no longer lost weight. Determinations of silver were made by ignition, the resulting silver being reheated and reweighed until it remained constant. * See Quarterly Journal of the Chemical Society, July 1858, page 130. 5 T. -0894 gramme of the salt gave '0580 gramme of metallic silver. II. *1597 gramme of the salt gave • 1022 gramme of metallic silver. Comparison of these results with the composition of acetate of silver gives as follows : — Calculated. Found. I. II. Per-centage of Silver 64-67 64'88 64-00 which leaves no doubt as to the presence of acetic acid. Still further proof of the same was obtained by converting a little of the acid into a soda-salt, and heating it with arsenious acid. Abundance of kakodyl was evolved. In order to remove any doubt which might exist as to the source of this acetic acid, and to show that it did not arise from oxidation of the ether which accompanied the sodium-methyl, I operated upon some of the original sample which had never been exposed to carbonic acid, and which, as previously mentioned, had been laid aside for comparison. I mixed it with a little mercury, distilled with excess of dilute sulphuric acid, and digested the redistilled distillate with oxide of silver, using the same samples of acid and of oxide of silver as in the former experiment. The distillate neither smelt like acetic acid, nor yielded acetate of silver on spontaneous evaporation to dryness in vacua of its product with oxide of silver. Neither could kakodyl be obtained on heating its soda-residue with arsenious acid. From all which it is evident that the acetic acid obtained must have been the product of the action of carbonic acid. The following conclusion is, therefore, established : — Dry carbonic acid is decomposed by sodium-methyl with evolution of heat, and production of acetate of soda. Sodium-methyl. Acetate of soda. A A f C204 + NaC2H3 C202C2H310 Na j 2* I hope also to be able to present shortly an account of the action of carbonic acid on one of the higher compounds of the alkali- metals — most probably on potassium or sodium-amyl. 6 May 12, 1859. Sir BENJAMIN C. BRODIE, Bart., President, in the Chair. The following communications were read : — I. "On the Resistance of Glass Globes and Cylinders to collapse from external pressure, and on the Tensile and Compressive Strength of various kinds of Glass." By WILLIAM FAIR- BAIRN, Esq., C.E., F.R.S., and T. TATB, Esq., F.R.A.S. Received May 3, 1859. (Abstract.) The researches contained in this paper are in continuation of those upon the Resistance of Wrought-Iron Tubes to collapse, which have been published in the 'Philosophical Transactions5 for 1858. The results arrived at in those experiments were so important as to suggest further inquiry under the same conditions of rupture with other materials ; and glass was selected, not only as differing widely in its physical properties from wrought iron, and hence well fitted to extend our knowledge of the laws of collapse, but because our acquaintance with its strength in the various forms in which it is employed in the arts and in scientific research is very limited. To arrive at satisfactory conclusions, the experiments on this mate- rial were extended so as to embrace the direct tenacity, the resist- ance to compression, and the resistance to bursting, as well as the resistance to collapse. The glass experimented upon was of three kinds : — Specific gravity. Best flint-glass 3-0782 Common green glass. . . . 2-5284 Extra white crown-glass 2*4504 Tenacity of Glass. — For reasons detailed by the authors, the ex- periments upon the direct tenacity of glass made by tearing speci- mens asunder are less satisfactory than those in the rest of the paper ; and it is argued that more reliance is to be placed upon the tenacity deduced from the experiments on the resistance of globes to bursting in which water-pressure was employed, than upon the tenacity obtained directly by tearing specimens asunder. The results obtained by the latter method give the following mean results : — Tenacity per square inch in pounds. Flint-glass 2413 Green glass 2896 Crown-glass 2346 Resistance of Glass to Crushing. — The experiments in this section were made upon small cylinders and cubes of glass crushed between parallel steel surfaces by means of a lever. The cylinders were cut of the required length from rods drawn to the required diameter, when molten, and then annealed, in this way retaining the exterior and first cooled skin of glass. The cubes were cut from much larger portions, and were in consequence probably in a less perfect condition as regards annealing. Hence, as might have been antici- pated, the results upon the two classes of specimens, although con- sistent in each case, differ widely from one another. The mean compressive resistance of the cylinders, varying in height from 1 to 2 inches, and about 0'75 inch in diameter, is given in the following Table : — Description of glaas. Height of cylinder in inches. Mean crushing weight per sq. in. Mean crushing weight per sq. in. in pounds. in tons. in pounds. in tons. Flint-glass X 1 1-5 2-0 29,168 20,775 32,803 13-021 9-274 14-644 127,582 12-313 Green glass ...« 1 1-5 2-0 22,583 35,029 38,105 10-081 15-628 16-971 U.1,876 14-227 Crown-glass ...j 1*0 1-5 23,181 38,825 10-348 17-332 1 31,003 13-840 The specimens were crushed almost to powder by the violence of the concussion ; it appeared, however, that the fracture occurred in vertical planes, splitting up the specimen in all directions. Cracks were noticed to form some time before the specimen finally gave way ; then these rapidly increased in number, splitting the glass into innumerable prisms, which finally bent or broke, and the specimen was destroyed. 8 The following Table gives the results of the experiments upon the cut cubes of glass : — Mean resistance to crushing in pounds. in tons. Flint-glass 13,130 20,206 21,867 6-861 9-010 9-762 Green glass Crown-glass • Hence, comparing the results on cylinders with those on cubes, we find a mean superiority in the former case in the ratio of 1*6 : 1, due to the more perfect annealing of the glass. On the Resistance of Glass Globes to internal pressure. — In these experiments the tenacity of glass is obtained by a method free from the objections to that before detailed. Glass globes, easily obtained of the requisite sizes, in a nearly spherical form, were subjected to an internal pressure obtained by means of a hydraulic pump, uni- formly and steadily increased till the globe gave way. The lines of fracture radiated in every direction from the weakest part, passing round the globe as meridians of longitude and splitting it up into thin bands, varying from -^th to ^th of an inch in breadth. The following Table gives the results of the experiments on the resistance of glass globes to internal pressure : — Description of glass. Diameters. Thickness. Bursting pressure per square inch. Inches. Inches. Pounds. r 4-0 X3-98 0-024 84 4-0 X3-98 0-025 93 Flint-glass - 4-0 4-5 X4-55 0-038 0-056 150 280 5-1 X512 0-058 184 6-0 0-059 152 4-95X5-0 0-022 90 Green glass J 4-95X5-0 4-0 X4-05 0-020 0-018 85 84 I 4-0 X4-03 0-016 82 4-2 X4-35 0-025 120 4-05X4-2 59 X5-8 0-021 0-016 126 69 6-0 X6-3 0-020 86 9 The formula which expresses the relation of the bursting pressure to the thickness and diameter of the globe, is — where a = the longitudinal sectional area of the material in square inches, that is in the line of rupture or line of minimum strength ; A = the longitudinal sectional area of the globe in square inches ; and T = the tenacity of the glass in pounds per square inch, Hence from the above experiments we deduce — Pounds. T=4200 for flint-glass, =4800 for green glass, =6000 for crown-glass. 5000 = mean tenacity of glass. Here the mean tenacity is nearly twice that obtained in the experi- ments upon thick bars ; a result, which perhaps corresponds with the difference between the crushing strength of cylinders and cubes, and is largely attributable to the condition of annealing. On the Resistance of Glass Globes and Cylinders to an external pressure. — The manner of conducting these experiments did not differ in any essential detail from that pursued in the experiments upon wrought iron. The globes and cylinders, after having been hermetically sealed in the blowpipe flame, were fixed in a wrought- iron boiler communicating with a hydraulic pump. In this position an increasing pressure was applied until the globes broke, the amount of pressure at the time being noted by means of a Schaffer pressure-gauge. During the collapse the globes were reduced to the smallest fragments, so that no indication of the direction of the primary lines of fracture could be discovered. The following Table contains a summary of the results on glass globes subjected to an external pressure : — 10 Description of glass. Diameters. Thickness. Collapsing pressure per square inch. Inches. Inches. Pounds. • 5-05X476 0-014 292 5-08X4-7 0-018 410 4-95X4-72 0-022 470 5-6 0-020 475 Flint-glass - 8-22x7-45 8-2 X7-2 0-010 0-012 35 42 8-2 X7-4 0-015 60 4-0 X3-98 0-024 (900*) 4-0 0-025 (900*) . 6-0 0-059 (1000*) Green glass 5-OX5-02 0-0125 212 The following Table contains a similar summary of the results upon cylindrical vessels : — Description of glass. Diameters. Length. Thickness. Collapsing pressure per square inch. Inches. Inches. Inches. Pounds. 3-09 14-0 0-024 85 3-08 14-0 0-032 103 3-25 14-0 0-042 175 4-05 7-0 0-034 202 Flint-glass ..." 4-05 7-0 0-046 380 4-06 13-8 0-043 180 4-02 13-8 0-064 297 3-98 14-0 0-076 382 4-05 7-0 0-079 (500f) The paper includes an investigation of the laws of collapse as exhibited in these results, and the following general formulae are obtained : — For glass globes P= 28,300,000 x ~ 7 1*4 For glass cylinders P= 740,000 x —— , where P = the collapsing pressure in pounds per square inch ; k = thickness in inches ; D and L = diameter and length re- spectively in inches. * These globes remained unbroken. t Remained unbroken. 11 These are the general formulae for glass vessels subjected to an external pressure, and the latter is precisely similar to that found for sheet-iron cylinders. Transverse Strength of Glass. — The authors derive the general formula W=3140x ^5, where W = breaking weight in pounds, K = area of transverse sec- tion, D = depth of section, I = length between supports ; — to express the transverse strength of a rectangular bar of glass supported at the ends and loaded at the middle. II. " On the Atomic Weight of Graphite." By BENJAMIN C. BRODIE, Esq., F.R.S., Pres. C.S., Professor of Chemistry in the University of Oxford. Received May 5, 1859. (Abstract.) In this paper the author arrives at the following results : — That carbon in the form of graphite forms a system of peculiar com- pounds, different from any compounds of carbon yet known, and capable of being procured only from graphite. That graphite, within certain limits, functions as a distinct element, capable indeed of being converted by certain processes of oxidation into carbonic acid and thus identified with the other forms of carbon, but having a distinct atomic weight, namely 33 (H=l). After the detail of certain experiments by which the author was led to believe in the existence of a distinct system of compounds of graphite, an account is given of a peculiar crystalline substance formed by the prolonged oxidation of graphite. This substance consists of transparent plates of a pale yellow colour, which exhibit under the microscope an appearance distinctly crystalline. The ana- lysis of this substance gave for its formula Cn H4 O5 (C= 12, O= 16). From the ratio of the hydrogen to the oxygen in this substance, from the circumstance that it is procured from graphite alone, and from its general physical properties, it is inferred that this substance is the term in the system of graphite which corresponds to the compound of silicon, oxygen and hydrogen, in the system of silicon, procured by Wohler from the graphitoidal form of that element, 12 and to which Wohler has assigned the formula Si4H4O5 (Si=21). If it be assumed that this conclusion is correct, the further inference is that the bodies are similarly constituted. On this hypothesis, to arrive at the atomic weight of graphite, the total weight of carbon, 132, is to be divided by 4, which gives the number 33 ; and for the formula of the body, putting Gr=33, we have Gr4H4O5. This conclusion is confirmed in a remarkable manner by the spe- cific heat of graphite. The specific heat of the elemental bodies varies inversely with their atomic weight. This law is so well established, that Regnault has even proposed to determine the atomic weight by it exclusively. There are, at any rate, only two numbers which can be assigned as the product of the specific heat into the atomic weight of the elemental bodies, namely, approxi- mately the numbers 3*3 and 6*6. But to this law there is one sin- gular exception. Carbon in all its forms is anomalous. The specific heats of diamond, graphite, and wood-charcoal are each different, and taking the atomic weight of carbon as 6 or 1 2, no one is accord- ant with the law. The specific heat of graphite is 0*20187. Now, taking the atomic weight of graphite as 33, we have 33X201 =6'63, a result in accordance with the law. The inference is, that the assertion that 33 is the atomic weight of graphite is not only a con- venient expression of chemical analysis, but corresponds to a phy- sical fact. May 19, 1859. Major-General SABINE, R.A., Treas. and V.P., in the Chair. Professor Henry Darwin Rogers was admitted into the Society. The following communications were read : — I. " On the Alloys."— Part I. "The Specific Gravity of Alloys." By A, MATTHIESSEN, Ph.D. Communicated by Prof. WHEATSTONE. Received May 17, 1859. (Abstract.) Before commencing a research into the electric conductivity of alloys, the author deemed it requisite, as a preliminary step, to 13 determine their specific gravities ; and the methods employed and results obtained in this inquiry are given in the present paper. The metals used were antimony, tin, cadmium, bismuth, silver, lead, mercury, and gold. The silver and gold were obtained in a state of purity from the refiners, the ether metals were purified by methods which are described. The quantity prepared of each alloy was twenty grammes. The fused alloys were cast in a form and very thin, to avoid internal cavities from crystallization. Three separate determinations were made of their specific gravity, which, to- gether with the mean result, are given in Tables. In every case the alloy was recast at least three times before the first determination, and once again before each succeeding one. The distilled water used in the weighing was first boiled and allowed to cool in vacuo, and the alloys were suspended in it by a fine platinum wire, except the soft amalgams, which were weighed in a tube similarly suspended. In calculating the specific gravities, the weight of water displaced was corrected for the temperature, the unit in all cases being distilled water at 0° C. All the weighings were reduced to a vacuum, and a correction was made for the platinum wire which dipped in the water. The numerical results are stated in three Tables, of which the first gives the specific gravities of the pure metals employed, and the tem- perature in Centigrade degrees ; the second gives the same of the al- loys ; and the third exhibits the mean specific gravities found, and the specific gravities as calculated, — 1, from the volume of the metals forming the alloy ; 2, from their equivalent ; and 3, from their weight. From the last Table it appears that the alloys of antimony are greater in volume than the aggregate of the constituent metals, while those of bismuth, silver, and gold are less. The following alloys ex- pand greatly on cooling, viz. all those of bismuth-antimony, bismuth- gold, and bismuth-silver, which were experimented on ; those of bismuth-tin, from Bi6 Sn to Bi2 Sn, the rest of the series very slightly ; and bismuth-lead, viz. Bi6 Pb and Bi4 Pb (Bi2 Pb slightly), the rest apparently not at all. Of the bismuth- cadmium series, Bi6 Cd and Bi Cd4 expand very slightly, the rest riot at all. The zinc-alloys are all so very crystalline that no results of value were obtained re- specting them. In making the determinations given in the paper, the author was assisted by Dr. M. Holzmann and Mr. C. Long. ]4 II. " On the Anatomy of Victoria Regia" Part II. By ARTHUR HENFREY, Esq., F.R.S., F.L.S. &c., Professor of Botany in King's College, London. Received May 5, 1859. (Abstract.) This paper is a continuation of one published in the Philosophical Transactions for 1852 (p. 289), and discusses the general question of the anatomical structure of the stems of Monocotyledons and Dicotyledons, especially in reference to some objections taken against the author's views respecting the stems of the Nymphseacese. Cer- tain peculiarities of the structure of roots are next examined, and these are shown to be formed on the Dicotyledonous type in Victoria. The germination of the seed is described in a manner differing to some extent from the accounts given by Planchon, Trecul, and Hooker. The error of Trecul, in stating that the earlier leaves are devoid of a stipule, is shown to depend upon his overlooking the true axillary position of that organ. The Phyllotaxy is next treated, with the development and arrange- ment of the leaves and roots ; lastly, a complete history of the develop- ment of the flower, showing that the apparently inferior position of the ovary depends upon a great enlargement of the receptacle after the formation of the various organs forming the flower. III. " On the Conductivity of Mercury and Amalgams." By F. GRACE CALVERT, Esq., and R. JOHNSON, Esq. Com- municated by Professor STOKES, Sec. R.S. Received April 14, 1859: (Abstract). The object of the researches described in this paper, was to carry out with reference to amalgams the investigations relative to alloys contained in a former paper. In comparing the results of theory and experiment in the manner followed in the former paper, the conducting power of mercury itself was a constant, which it was essential to know. The figure given in the former paper was mercury =6 77, on the scale silver =1000. On adopting in the first instance this value of the conducting power of mercury, the results 15 obtained with alloys, which consisted mainly of mercury, appeared very anomalous ; it seemed as if a very small per-centage of even the best conducting metals reduced immensely the conducting power of mercury. But it was suggested to the authors, that the apparently high conducting power of mercury obtained by their method, was probably due to the transference of heat by convection ; that the real conducting power of mercury for heat was low, like its conduct- ing power for electricity ; that the other metal, contained in small quantity in the amalgam, acted by rendering the amalgam viscous, and thereby interfering with the transference of heat by convection, and that the low conducting power of mercury would show itself on merely inclining the vessel used in the experiment, so that the box containing the warm water should be higher than the other. Ex- periment confirmed this view. As the apparent conducting power of mercury was found continually to decrease with an increase in the inclination of the vessel, it was found necessary, in order to obtain correct results, to arrange so that the bar-shaped box containing the mercury or fluid amalgam was actually vertical in the experiment. In this way the authors obtained for mercury the figure 54, on the same scale as before. It is worthy of remark, that mercury comes out the worst conductor of all the metals tried, the figure for bismuth, which had previously been the lowest, being 6 1 . This is in analogy with water, also a fluid, the conducting power of which is known to be excessively low. The conducting power of the more fluid amalgams determined by experiment with the box vertical, proved to be in all cases nearly the same as that of pure mercury, in conformity with the law mentioned by the authors in their former paper, that alloys in which there is an excess of the number of equivalents of the worse conducting metal, over the number of equivalents of the better conductor, do not sensibly differ in con- ducting power from the worse conductor alone. In the case of amalgams generally, the conducting power obtained by experiment was found to agree pretty closely with the number calculated from the per-centages and conducting powers of the component metals. In conclusion, the authors give some further experiments on the conduction of heat by compound bars, formed of metals placed in some cases end to end in alternate cubes, in other cases side by side in parallel bars, extending the whole length of the compound bar. 16 Among bars of the latter kind, it was found that it was only in the case of bismuth and antimony that the compound bar conducted heat according to the calculated amount. May 26, 1859. Sir BENJAMIN C. BRODIE, Bart., President, in the Chair. The following communications were read : — I. "On the Intimate Structure, and the Distribution of the Blood- vessels, of the Human Lung." By A.T.H. WATERS, Esq., Lecturer on Anatomy and Physiology, Liverpool. Com- municated by Dr. SHARPEY, Sec. R.S. Received April 7, 1859. Having been recently engaged in investigating the anatomy of the human lung, I beg to lay before the Royal Society some of the results of my observations with respect to the arrangement of the ultimate air-tubes and the distribution of the blood-vessels of the organ. The bronchial-tubes of the lungs, after several divisions and sub- divisions, which for the most part are of a dichotomous nature, terminate in a dilatation, into which open a number of elongated cavities, which constitute the ultimate expressions of the air-tubes. These elongated cavities, to which various names have been given, I propose to call air-sacs, as being, in my opinion, more appropriate to their shape and arrangement than any term hitherto used ; and the series of air-sacs connected with the extremity of each bronchial twig, with its system of blood-vessels, &c., I shall call a lobulette. Every lobule of a lung is composed of a number of lobulettes, and thus the description of a single lobulette will suffice for that of the entire lobule. Each lobulette consists of a collection of air-sacs, which vary in number from six to eight, ten or twelve. The air-sacs are some- what elongated cavities, communicating with the dilated extremity of a bronchial tube by a circular opening, which is usually smaller than the sac itself, and has sometimes the appearance of a circular hole in a diaphragm, or as if it had been punched out of a membrane which 17 had been stretched across the entrance to the sac. When this is the case, the sac dilates suddenly beyond the opening. The sacs of the lobulette are placed side by side, and are separated from each other by thin membranous walls. Their shape, when properly inflated, or when distended by some material which has set in them, as gelatine, or a mixture of wax and turpentine, is polygonal. They approach the circular form, but in consequence of their mutual pressure, the parietes become somewhat flattened. The sacs increase slightly in size as they pass from the bronchial tube to their fundus, the latter being usually the broadest part of the sacs ; but they often have an almost uniform diameter throughout. All the sacs pass from the extremity of the bronchial tube towards the circumference of the lobule of which the lobulette forms a part ; they consequently radiate from the tip of the bronchial twig. The sacs connected with one lobulette do not communicate with those of another lobulette. As the sacs pass towards the boundary of the lobulette, they often bifurcate ; and here and there circular orifices exist, leading to smaller air-sacs, sometimes only to a small group of " air-cells," or alveoli. If we trace the air-sacs from their fundus, we may say that, passing from the periphery of the lobulette, and diminishing some- what in size, they all terminate in the dilated extremity of the bron- chial tube ; as they thus proceed they often join two or three together, and these terminate in a single mouth. The tube which results from the union of two or more sacs, is smaller in capacity than the sacs taken together, but greater than either of them indi- vidually. The dilated extremity of the bronchial tube above alluded to constitutes the "point de reunion" of all the air-sacs, and may be considered as the common centre of the lobulette. The walls of which the air-sacs are composed are exceedingly thin, and much sacculated, t. e. they have in them a number of small, shallow, cup-like depressions, separated from each other by portions of membrane which are more or less raised and project into the interior of the sac. The bottom of the air-sac presents the same appearance as the lateral walls; and the cup-like depressions, or alveoli, are there very numerous. The number of these alveoli varies very much ; I have counted as many as ten at the fundus of an air- sac in a cat's lung ; in the human lung I have counted five and six, but the number is not usually quite so great. Close to the bottom VOL. x. o 18 in some of the air-sacs in the human lung, a circular opening, similar to those already alluded to as leading to other sacs, small and con- stricted, is often seen, and has the appearance as if it led to another sac ; on examination, however, it will be found to be produced by a projection inwards of the membrane of the sac, and to lead to a small cavity, or group of alveoli. The number of alveoli existing in the air-sacs varies — Rossignol states that each "infundibulum" (air-sac) contains from ten to twenty alveoli. My own observations entirely accord with this statement. I have found the number varying from eight to twenty. The air-sacs externally, by their fundus, rest on the pleura, but within the substance of the lung they in part rest on, and are sup- ported by, the bronchial tubes and blood-vessels. The air-sacs are separated from each other by thin walls, the membrane composing which, in a lung inflated and dried, is very transparent. The projection of this membrane in the shape of a thin process, having a sharp margin, constitutes the septa between the alveoli ; and wherever an opening exists leading into a smaller sac, this membrane projects in a similar way, and forms a circular orifice which is much smaller than the cavity to which it leads : — the sac, in fact, dilates abruptly on the distal side of the opening. It is in the membrane composing these walls, and in the septa of the alveoli, that the capillaries of the pulmonary artery are spread out. The number of air-sacs belonging to a lobulette varies : I have counted as many as six communicating with a bronchial tube incised horizontally, so that probably only half the sacs were left ; this, however, is a larger number than is usually found ; from six to eight or ten is the more common number. Each lobulette is separated from those by which it is surrounded, by walls which appear to resemble in every way the walls of the air- sacs ; and in an adult inflated and dried lung, careful observation is necessary to make out the partitions. That perfect septa do exist, is proved by laying open, in a recent lung, a bronchial tube to its ultimate division, when by placing a fine blowpipe in it, and blow- ing down it, a single lobulette is alone inflated. The separation of the lobulettes is further distinctly perceptible in the recent lungs of infants, in which the line of demarcation between the lobulettes is often plainly seen, on the surface. 19 The observation of the foetal lung, however, affords most satis- factory evidence of the separation of the lobulettes, and tends to confirm the views here taken of the arrangement of the ultimate air- tubes. The recent lung of a full-grown foetus presents on its surface no appearance of air-sacs, or vesicles, or cells ; but if it be inflated, it will present different appearances, according as the inflation has been partial or entire. In a portion of lung only partially inflated, a number of tubes will be seen terminating beneath the pleura in csecal extremities, their light colour contrasting strongly with the sur- rounding dark-coloured tissue. The exact arrangement of these tubes may be sometimes seen. They will be found to exist in groups or clusters, and are seen to pass from the csecal ends to a point, in which they terminate, and where they all appear to join ; or, to de- scribe them in the inverse direction, they pass from a point at some distance from the surface, and radiate towards the pleura. The tubes are seen to have numerous constrictions and bulgings ; they terminate in extremities rounded, or nearly so. In a preparation of this kind it is often easy to see the bronchial tube for a short dis- tance before it terminates ; and not only is the terminal group of air- sacs (lobulette) visible, but two or more of the previous ones arising laterally from the bronchial tube may be also seen. The uninflated lung-substance lying between the distended air-sacs is distinctly seen when there has been only slight inflation ; and the isolated condition of each group of sacs is very apparent ; the sacs passing from dif- ferent points are seen radiating in different directions. In a lung which has been fully inflated, the grouped appearance is lost, and the ordinary condition of the distended lung is observed. If, in a foetal lung, we follow out a bronchial tube, we find that the smaller branches of the tube have connected with them clusters of little pyriform red- coloured bodies, which look very much like a number of grapes attached to their stalks. In a foetus of six months I have found it somewhat difficult to separate each individual body, but in a full-grown foetus there is no difficulty in doing so; each little body is attached to a short pedicle. If air be blown down a bronchial tube leading to the exposed bodies, the latter become distended. The little bodies just described are the ready-formed groups of air -sacs, or lobulettes ; the pedicle with which each is connected is c 2 20 the terminal bronchial twig. The lobulette thus formed is sur- rounded by its sheath, and no communication exists between it and adjoining ones. That the appearances I have described in the artificially inflated foetal lung are not the result of any abnormal distension, I have been able to prove by observing the same appearances in the lung of a child in which only partial respiration had taken place. Do the air-sacs communicate with each other by any orifices ex- cept that by which they communicate with the bronchial tube ? Different opinions have been expressed on this point. Adriani states that he has observed such orifices, and specially mentions that they are most clearly to be seen in the stag. Dr. Thomas Wil- liams considers that the " intercellular passages " intercommunicate, and are perforated by secondary passages at every point. Rossignol, Schultz, Mandl, and Milne-Edwards, deny the existence of such communications. From observations, made with much care and frequently repeated, I have satisfied myself that the opinion expressed by the latter authors is correct. I have never found, either in the lung of man or in that of the dog, cat, pig, sheep, or any other mammal I have examined, any lateral orifices of communication between the sacs of a lobulette. Alveoli of the Bronchial Tubes. — The termination of the bronchial tubes has a special character, first pointed out by Rossignol. He says, " In the bronchial divisions of the two last, and sometimes three last orders, it is plainly seen, when they are opened longitudinally, that their surface is covered over, or, as it were, honeycombed with a number of small, regular, shallow cavities, placed side by side, and separated by thin perfect walls of the same height, which project into the interior of the bronchial tube." The existence of these bronchial alveoli has been noticed by subsequent observers ; they may be easily seen in a lung injected and inflated, and sometimes even in one which has been simply soaked in spirit for a few days ; they resemble the alveoli of the air-sacs ; they are best seen in the lungs of some of the lower animals, as the cat, in which they are found in the ultimate bronchial tubes and their dilated extremities. In man I have never seen them, except at the extremity of the tubes ; and in many lungs I have found no appearance of them at all — they appear to become obliterated with advancing age. In the 21 infant I have found them in the last divisions of the bronchial tubes, and their dilated extremities, but not in the penultimate or earlier branches ; and even in the last divisions they are not always present previous to the dilatation. In respect of the extent, therefore, to which these alveoli exist in the human lung, my observations do not quite accord with those of Rossignol. The Blood-vessels of the Lungs. — The branches of the pulmonary artery accompany the bronchial tubes, arrived at the extremity of which, they give off branches to the bronchial alveoli, and terminate in vessels which take their course in the walls of the air- sacs in no very definite or regular manner. From these vessels the pulmonary plexus arises. The pulmonary veins, receiving the blood from the plexus of the air-sacs, pass from the periphery of the lobulettes, and running in the spaces between the lobules, make their way, independently, to the root of the lung. The pulmonary plexus is situated in the walls which separate the air-sacs, in the septa of the alveoli, and around the margins of the openings which exist in the sacs. The plexus consists of a single layer of vessels, which, as already pointed out by Mr. Rainey, is in no instance doubled on itself. In the septa of the alveoli, and in the margins of the orifices alluded to, the plexus does not reach quite to the free border of the membrane composing them. There is no distinct and separate vessel for each alveolus, but the branches of the terminal artery take their course along the walls of the air-sacs, and give on7 branches which for the most part run in the septa of the alveoli ; some of them, however, pass across the alveoli. From these vessels, and from the branches first mentioned, the capillary plexus arises. The plexus, when formed, maintains a tolerably uniform size throughout. In a well-injected preparation, inflated and dried, it will be seen that the spaces between the vessels are somewhat greater in diameter than the vessels themselves. The branches of the pulmonary artery do not anastomose till they reach the termination of the bronchial tubes ; on the air-sacs they anastomose freely. It is somewhat difficult to decide whether the vessels of one lobulette anastomose with those of another. On look- ing at a preparation injected and dried, it seems as though the septum, separating one lobulette from another, resembled in every 22 respect the walls of the air-sacs ; but as the lobulettes are originally separate and independent bodies, as seen in the foetal lung, it is pro- bable that the vessels of each are distinct. If so, there must be, where the walls of two lobulettes are in contact, two layers of capil- laries lying side by side ; and from the mode of formation of the lobulettes, and from the fact that I have been able, in some prepa- rations of the adult lung, partially to separate the lobulettes from one another, I believe that their vessels are distinct, that they ter- minate in their proper radicle-vein, and that thus the capillaries on the outer wall of the lobulette are only exposed on one side to the atmosphere. The Bronchial Vessels. — It has long been held that the bronchial arteries are distributed to the air-tubes, the areolar tissue, and the vessels of the lungs, and that they pour their contents partly into the pulmonary veins, and partly into certain deep bronchial veins, which have been described by most anatomists as accompanying the arteries within the lungs. An opinion has also been entertained that a communication exists between the bronchial vessels and the branches of the pulmonary arteries. Without referring to the ex- periments and results of other observers, I proceed to state my own. My observations have been made on the lungs of the cat, the dog, the rabbit, the pig, the calf, and the sheep, as well as on those of man. The following remarks have special reference to the results obtained in the human lung. When the pulmonary artery is injected so that the fluid reaches the pulmonary plexus but does not pass to any extent into the pul- monary veins, the blood-vessels of the bronchial mucous membrane and of the other portions of the bronchial tubes never become in- jected. When, however, the injection is continued so as to fill the pulmonary veins, the vessels of the bronchial tubes become partially injected. When the pulmonary veins are injected, whether the pulmonary plexus be well-filled or not, the vessels of the bronchial tubes and of the bronchial mucous membrane are always injected. The bronchial tubes are often seen to be injected when the pulmonary plexus is only very partially so, the fluid seeming to find its way from the pulmonary veins into the vessels of the bronchial tubes more readily than into the capillaries of the air-sacs. 23 When a bronchial artery, as it enters the substance of the lung, is injected, the vessels of the bronchial tubes become filled — both those of the mucous membrane and of the deeper portions — and the fluid finds its way into the pulmonary veins. If the injection be con- tinued, it is easy to inject the pulmonary plexus through the medium of the bronchial arteries ; and injection is often found in the branches of the pulmonary arteries. In injecting a bronchial artery in the human subject, I have always found that part of the bronchial tubes nearest the point of insertion of the injection pipe more fully injected, both as regards the mucous membrane and the deeper structures, than the parts situated towards the extremity of the tubes. I have found the larger branches injected nearly to the end of the tubes, but not the fine vessels of the mucous membrane. This seems to me to be due to the fact, that throughout the entire extent of the tubes there is so free a communication be- tween the bronchial vessels and the pulmonary veins, that the fluid finds its way into the latter more readily than into the fine plexus of the extreme tubes. The Bronchial Veins. — The examination of a large number of specimens, both of the lungs of man and the lower animals, and the injection of the vena azygos on several occasions, have not enabled me to find the so-called deep bronchial veins, as vena comites of the bronchial arteries. I have always found a small vein or veins, gene- rally a single one, situated at the posterior aspect of the bronchus, and terminating, as shown by the injection, in the structures of bronchus, lower part of trachea, and glands at the root of the lung, but not passing along the bronchial tubes within the lung, and therefore being in no way concerned in returning the blood distri- buted to those parts by the bronchial arteries. A piece of human lung well injected by the bronchial artery, ex- hibits on the mucous membrane of the bronchial tubes, a fine plexus of vessels, taking for the most part a longitudinal direction ; under these other vessels are found, which run transverselv beneath the elastic tissue, in the direction of the muscular fibres ; these deeper vessels are larger than the superficial ones ; there is a distinct com- munication between the two sets. I now pass to consider in what manner, and wheret the communi- 24 cation which undoubtedly exists between the pulmonary and bron- chial vessels, takes place. If the statement I have made with reference to the bronchial veins be true, those vessels do not return the blood supplied by the bron- chial arteries, except so far as the latter vessels distribute it to the bronchi themselves and the structures about the root of the lung ; and the next point we have to examine is whether any communica- tion exist between the bronchial arteries and the pulmonary arteries. In all the best injections I have made, whether in man or the lower animals, in which the injection was introduced by the pulmonary artery, I have never found the vessels of the bronchial tubes injected unless the pulmonary veins were well-filled, and in such specimens I have seen vessels passing from the bronchial tubes, and joining a branch of a pulmonary vein. I have found branches of the pulmonary artery containing injection, when the latter has been introduced through the bronchial artery ; but in such specimens I have found portions of the pulmonary plexus injected, and I believe the injection has found its way through the plexus into the pulmonary arteries. I have never seen the vessels described by some anatomists as passing from the pulmonary artery to the bronchial tubes. With regard to the communication of the bronchial vessels with the pulmonary veins, it admits of ocular proof. It is unquestion- ably more easy to inject the vessels of the finer bronchial tubes through the pulmonary veins, than through the bronchial arteries at the root of the lung ; it is also possible to inject those vessels to a certain extent through the pulmonary veins, without injecting the pulmonary plexus. On the other hand, the injection thrown in through the bronchial arteries rapidly and readily finds its way into the pulmonary veins. These facts seem to prove that the blood dis- tributed by the bronchial arteries within the lung is poured into the pulmonary veins, and that the whole vascular system of the bron- chial tubes communicates with the same veins. It has been stated by Mr. Rainey, that the vessels of the bronchial tubes anastomose at the extremity of the tubes with the vessels of the " air-cells" (air- sacs). In this I cannot concur, for I have never been able to fill these extreme vessels by injection through the pul- monary artery. My belief is, that at the termination of the tubes, as elsewhere, the blood of the bronchial arteries is poured into the pulmonary veins. Dr. Heale has advanced the opinion that the bronchial arteries do not supply the bronchial mucous membrane at all, and that they neither communicate with the pulmonary arteries nor veins. My observations have given results entirely opposed to this view. With reference to the view taken by Adrian!, and subsequently adopted by Dr. Thomas Williams, that the vessels of the bronchial mucous membrane terminate in the pulmonary veins, and those of the deeper plexus in the bronchial veins, it is not borne out by the experiments I have made, which appear to prove that not only do the same vessels supply the superficial and deep plexuses of the tubes, but that both plexuses discharge their contents into the same receptacles. II. "On Certain Sensory Organs in Insects, hitherto unde- scribed." By J. BRAXTON HICKS, M.D. Lond., F.L.S. &c. Communicated by JOHN W. LUBBOCK, Esq. Received May 14, 1859. (Abstract.) The author commences with an allusion to papers published in the Linnean Society's * Journal' and 'Transactions' respecting groups of organs, abundantly supplied with nerves, on the bases of the halteres of Diptera, also on the nervures of the wings and on the elytra of Coleoptera ; and now gives a drawing which shows forth these organs, and the nerve proceeding to them on the halteres. He then describes, for the first time, somewhat similar organs on the apices of the palpi of some Diptera, and on their base in many Hymenoptera, as Apis, Vespa, Nomada, Megachile, Bombus, &c. These are well shown in the Vespa Crabro, or Hornet, where the nerve is seen expanding in the thin membrane which covers in the opening beneath in the wall of the member. In the paper also, it is pointed out for the first time, that on the apex of the palpi of Lepidoptera there is invariably found a structure which is more or less of a cavity, generally tubular, and sometimes extending inwards nearly the length of the last segment, but some- 26 times only a depression. To it a nerve is given which expands on the apex of the cavity. The author then describes groups of organs, allied in form to those on the palpi, which are to be found on the legs of all insects yet examined. There are about three groups situated about the tro- chantero-femoral joint, and to them nerves can be distinctly seen proceeding ; and in Meloe the branch is seen to pass up the opening in the wall, to terminate in a papilla in the centre of the membrane covering it in. It is also shown that the bladder-like apex of the palpi, instead of being smooth, as is generally described, is covered with a great number of small bodies, something in form like ninepins, some- times exceedingly small, requiring a J-inch objective to make them out, when they can clearly be discerned to be a modified condition of true hairs, copiously supplied with nerves. The author names these " tactile hairs," and points out their existence in all palpi used for touching, and in other organs subservient to that function. These tactile hairs are very large in the palpi and antennae of Dyticus mar- ginalis. The barrel-like organs of the Lepidoptera are next investi- gated, and are shown to have a nerve passing up them ; but whether proceeding to the apex of the nipple-like papilla on them or not, cannot be quite made out. They are pointed out as being nearly allied to the organs on each of the palpi of the Earwig (Forficula auricularia) . The author refers to the sacs found on the antennae of all insects, which have been fully treated of in two papers read by him before the Linnean Society, and published in their ' Transactions ;' and he lastly examines the probable functions of all these organs, which must be of sensation, probably special. Attention is also called to the value of bleaching the tissues by chlorine in investigating the structure of insects, which process was first used by the author and described by him in the papers above mentioned. About forty drawings accompany the paper illustrative of the structures described. 27 III. " On Lesions of the Nervous System producing Diabetes." By FREDERICK W. PAVY, M.D. Lond. &c. Communicated by Dr. SHARPED Sec. U.S. Received May 17, 1859. (Abstract.) The author commenced his paper by stating, that all the experiments he had performed since his communication on the " Alleged Sugar- forming Function of the Liver " had been placed in the possession of the Royal Society, had confirmed the conclusions he had there arrived at. As far as his knowledge extended, it might be said that in the healthy liver during life there is a substance which he had spoken of under the term of hepatine, and which possesses the che- mical property of being most rapidly transformed into sugar when in contact with nitrogenized animal materials. In the liver after death this transformation takes place, but in the liver during life there seems a force or a condition capable of overcoming the che- mical tendency to a saccharine metamorphosis. Experiments are mentioned to show that when the medulla oblon- gata is destroyed, and the circulation is maintained by the performance of artificial respiration, the sugar formed in the liver as a post- mortem occurrence is distributed through the system, and occasions the secretion of urine possessing a strongly saccharine character. Although the destruction of the medulla oblongata leads to this effect, yet division of the spinal cord, which has been practised as high as between the second and third cervical vertebrae, has not been attended with a similar result. The brain (cerebrum) has also been separated from the medulla oblongata by section through the crura cerebri, and from the results of the experiments in which this operation has been performed, Dr. Pavy believed that the functions of the brain may be completely destroyed, without placing the liver in the condition no- ticeable after actual death, or after lesion of the medulla oblongata, On account of the accidental disturbances, — such as implication of the medulla oblongata, possibly by concussion, obstruction of the respi- ration, and the effects of the great loss of blood sometimes attending division of the crura cerebri, — the interpretation of the result is ren- dered a little difficult. In an experiment, which proved most con- clusive, performed to corroborate the author's previous observations 28 whilst his communication was being written, there were none of these disturbing circumstances. In a healthy dog, during a period of diges- tion, the crura cerebri were completely divided. The animal was thereby thrown into a state of unconsciousness, but breathed efficiently of its own accord. The urine in an hour and a quarter's time was found perfectly free from sugar. After poisoning by strychnine, the effect is the same as after de- struction of the medulla oblongata. The circulation being maintained by artificial respiration, the urine becomes strongly saccharine. Looking to these facts, and to the effect of Bernard's puncture of the fourth ventricle in producing diabetes, the author is led to regard the medulla oblongata as a centre, either directly presiding over the functional activity of the liver, or indirectly affecting it by altering through the medium of another or other organs the condition of the blood going to it ; and he has endeavoured to establish upon positive grounds the channel by which the propagation of the nervous influ- ence may take place. It was this line of research that conducted to the discovery of the strongly diabetic effect produced by dividing- certain parts of the sympathetic. The medulla oblongata being thus presumed to form a centre giving to the liver a force which prevents the saccharine" metamor- phosis of its hepatine, experiment had already shown that it cannot be through the spinal cord or the pneumogastrics separately, that the transmission of nervous influence takes place. But an experiment was performed to determine the effect of dividing both the spinal cord and the two pneumogastrics together. The cord was crushed between the third and fourth cervical vertebrae, and about half an inch of each pneumogastric was cut away from the centre of the neck. Artificial respiration was performed to keep up the circulation. The urine remained entirely free from sugar, and the liver was found in an exsaccharine state at the moment of discontinuing the respiration, and became strongly saccharine afterwards. On next dividing all the nerves in the neck, an operation effected by performing decapitation, the result that followed after three quarters of an hour's artificial respiration was strongly saccharine urine. After this experiment, and that of division of the spinal cord and pneumogastrics, reason was afforded for looking to the sympathetic ; and from the experiments that have been made and are described, 29 the following conclusions have been arrived at. The animal selected for observation has been the dog, subsisting upon an animal diet, and operated upon at a period of full digestion. " Division, on both sides of the neck, of the ascending branches of the superior thoracic ganglion which run up towards the canal formed by the foramina in the transverse processes of the vertebrae, for the vertebral artery, occasions an intensely marked diabetes. The urine has been found most strongly saccharine within even half an hour after the operation. The diabetic condition is only of a temporary character, passing off by the next day, and fatal pleurisy is always induced. " Division of the ascending branches of the superior thoracic ganglion on one side of the neck only, has occasioned merely the presence of a trace of sugar in the urine in an hour and a half s time. The same operation then performed on the other side has produced in half an hour's time an intensely saccharine urine. " Carefully ligaturing the two vertebral and the two carotid arte- ries does riot lead to saccharine urine ; but when the carotids have been tied, and the tissue in connexion with the vertebrals before their entrance into the canals is a little roughly treated, without however dividing the larger sympathetic filament ascending from the superior thoracic ganglion, the urine is rendered rapidly and strongly saccha- rine. "Division of the sympathetic filaments that have entered the canals does not alone produce diabetes ; but if the contents of these canals be divided, and the carotid arteries at the same time ligatured, saccharine urine is the result. " This result is produced when the contents of the osseous canals are divided as high as the second cervical vertebra. It has also arisen after destroying the structures in the neighbourhood of the vertebral foramen on the posterior surface of the transverse process of the atlas, but has not yet been noticed after a similar operation on the anterior surface of the process. " Dividing the contents of the canals and the tissue in immediate contact with the carotid vessels has not produced diabetes ; but when the carotids have been afterwards tied, strongly saccharine urine has resulted. " Of all the operations on the sympathetic of the dog that have yet 30 been performed, removal of the superior cervical ganglion the most rapidly and strongly produces diabetes. After the removal of one ganglion, the urine has been found intensely saccharine in an hour's time, and the saccharine character has remained during the following day, but has disappeared by the next. Subsequent removal of the other ganglion a few days later has been followed in half an hour's time with a strongly marked diabetic effect, which, however, has been again only of a temporary nature. " Division of the sympathetic in the chest has been several times succeeded by saccharine urine. In one case after division on one side only, the urine was intensely saccharine in half an hour's time. On the other hand, many experiments have been made where both sides have been operated on, and only a merely traceable, or in a few instances, even no effect, has been noticeable. " In the rabbit, removal of the superior cervical ganglia, when the animal is in a strong and healthy state, is followed by diabetes; but the effect is not so rapidly produced as in the dog. It has been noticed at the end of four hours after the operation, and has been observed to exist until the following day. " Excision of the superior cervical ganglia in the rabbit with a division of the pneumogastrics above their gangliform enlargement close to their exit from the skull, has been attended with the produc- tion of saccharine urine in a shorter space of time than when the ganglia alone have been removed, notwithstanding that division of the pneumogastrics in the situation referred to, has not been seen by itself to cause any positive effect." Such is a simple statement of the principal conclusions derivable from the author's experiments, which are given in detail in his com- munication. As to the interpretation of the results that have been obtained, this he leaves for further investigation, in which he is now engaged, if possible, to disclose. The experiments on the sympathetic were commenced under the notion that it might form the medium of transmission of nervous force from the medulla oblongata to the liver. From this supposition certain facts have been discovered which are left for the present, without discussing whether the notion that led to them is right or wrong. 31 IV. " On the Electrical Condition of the Egg of the Common Fowl." By JOHN DAVY, M.D., F.R.S.S. L. & E. &c. Received May 19th, 1859. (Abstract.) The structure of the egg suggested to the author the idea of its exerting electrical action. This was confirmed on trial. Using a delicate galvanometer and a suitable apparatus, on plunging one wire into the white, and the other, insulated, except at the point of con- tact, into the yolk, the needle was deflected to the extent of 5° ; and on changing the wires, the course of the needle was reversed. "When the white and yolk were taken out of the shell, the yolk immersed in the white, the effects on trial were similar ; but not so when the two were well-mixed ; then no distinct effect was perceptible. Indications also of chemical action were obtained on substituting for the galvanometer a mixture consisting of water, a little gelatinous starch, and a small quantity of iodide of potassium, especially when rendered very sensitive of change by the addition of a few drops of muriatic acid. In the instance of newly-laid eggs, the iodine libe- rated appeared at the pole connected with the white ; on the con- trary, in that of eggs which had been kept some time, it appeared at the pole connected with the yolk, answering in both to the copper in a single voltaic combination formed of copper and zinc. The author, after describing the results obtained, declines specu- lating on them at present, merely remarking, that in the economy of the egg, and the changes to which it is subject, it can hardly be doubted that electro-chemical action must perform an important part, and that in the instance of the ovum generally, i. e. when com- posed of a white and of a yolk, or of substances in contact, of hete- rogeneous natures. V. "On the Mode in which Sonorous Undulations are con- ducted from the Membrana Tympani to the Labyrinth, in the Human Ear." By JOSEPH TOYNBEE, Esq., F.E.S. &c. Received May 24, 1859. The opinion usually entertained by physiologists is that two channels are requisite for the transmission of sonorous undulations from the membrana tympani to the labyrinth, viz. the air in the tympanic cavity which transmits the undulations to the membrane of the fenestra rotunda and the cochlea ; and secondly, the chain of ossicles which conduct them to the vestibule. This opinion is, however, far from being universally received ; thus, one writer on the Physiology of Hearing contends that " the integrity of one fenestra may suffice for the exercise of hearing*;" another expresses his conviction that " the transmission of sound cannot take place through the ossiculaf;" while Sir John Herschel, in speaking of the ossicles, says " they are so far from being essential to hearing, that when the tympanum is destroyed and the chain in consequence hangs loose, deafness does not follow J." The object of this paper is to decide by experiment how far the ossicles are requisite for the performance of the function of hearing. The subject is considered under two heads, viz.— 1. Whether sonorous undulations from the external meatus can reach the labyrinth without having the ossicles for a medium. 2. Whether any peculiarity in the conformation of the chain of ossicles precludes the passage of sonorous undulations through it. 1. Can sonorous undulations reach the labyrinth from the external meatus without the aid of the ossicles ? This question has often been answered in the affirmative, appa- rently because it has been ascertained that in cases where two bones of the chain of ossicles have been removed by disease, the hearing power is but slightly diminished. In opposition to this view, it must, however, be remembered, that the absence of the stapes, or even its fixed condition (anchylosis), is always followed by total or * Mr. Wharton Jones, Cyclopaedia of Surgery, Art. " Diseases of the Ear," p. 23. t Lancet, 1843, p. 380. J Encyclopaedia Metropolitana, Art. " Sound," p. 810. 33 nearly total deafness ; and the following experiments, which demon- strate the great facility with which sonorous undulations pass from the air to a solid body, indicate that the stapes, even when isolated from the other bones of the chain, may still be a medium for the transmission of sound. Experiment 1. — Both ears having been closed, a piece of wood, 5 inches long and half an inch in diameter, was held between the teeth, and a vibrating tuning-fork C' having been brought within the eighth of an inch of its free extremity, the sound was heard distinctly, and it continued to be heard between five and six seconds. Experiment 2. — One end of the piece of wood used in the pre- vious experiment being pressed against the tragus of the outer ear, so as to close the external meatus without compressing the air con- tained within it, a vibrating tuning-fork C' placed within a quarter of an inch of its free extremity, was heard very distinctly at first, and it did not cease to be heard for fifteen seconds. Experiment 3. — Three portions of wood, of the same length and thickness as that used in the previous experiments, were glued together so as to form a triangle somewhat of the shape of the stapes ; the base of this triangle being placed against the outer surface of the tragus, as in the previous experiment, the tuning-fork C' vibrating within a quarter of an inch from its apex was heard for twelve seconds. Considering, as shown by the above experiments, the great facility with which sonorous undulations pass from the air to a solid body, it may, I think, be assumed that the undulations in the tympanic cavity may be conveyed to the stapes even when this bone is isolated from the rest of the chain, and conducted by it to the vestibule ; and when it is also considered that the absence of all the ossicles, or even a fixed condition of the stapes, is productive of deafness, there is strong evidence in favour of the opinion that sounds from the external meatus cannot reach the labyrinth without the medium of the ossicles. 2. 7* there any peculiarity in the conformation of the chain of ossi- cles which precludes the passage of sonorous undulations through it ? This question has also been answered in the affirmative, on account of the various planes existing in the chain ; and secondly, on account of the joints existing between the several bones composing this chain. VOL. X. D 34 The following experiments refer to the influence of the varying plane of the bones forming the chain, and of its articulations, on the progress of sonorous undulations through it : — I. Experiments illustrative of the influence of the variety of planes in the chain. Experiment 1 . — Three pieces of wood, each 5 inches in length and half an inch thick, were glued together thus /\ , so as to represent the planes in which the malleus, incus, and stapes are arranged in the chain of ossicles, while three similar portions were glued end to end so as to form a straight rod. A watch was placed in contact with one end of the straight rod, while the other was pressed gently against the tragus so as to shut the external meatus. The result was that the watch was heard nearly as distinctly as when in contact with the ear. When a similar experiment was per- formed with the angular portion of wood representing the chain of bones, the watch was also heard, but less distinctly than through the straight portion. Experiment 2. — A tuning-fork C', being made to vibrate, was placed in contact with one extremity of the angular piece of wood, the other being placed against the tragus of the ear ; and as soon as the sound ceased to be heard, the straight portion was substituted, when the tuning-fork was again heard, and it continued to be heard for about three seconds. Experiment 3. — A vibrating tuning-fork C' was placed at one ex- tremity of the angular piece of wood, the other extremity being held between the teeth ; the fork was at first heard very distinctly, and when its sound could no longer be distinguished, the straight piece was substituted, and it was again heard for the space of two seconds. Experiment 4. — Instead of the horizontal portion of wood repre- senting the stapes, three portions of the same size were made into a triangle, and this was glued to the anterior surface of the inferior extremity of the piece representing the incus, thus A^ • The previous experiment was then repeated with the substitution of this apparatus for the angular one, and with nearly the same result, viz. the fork was heard through the straight piece about three seconds 35 after it had ceased to be heard by the apparatus representing the chain of bones. Experiment 5. — A piece of very thin paper was gummed over the end of a glass tube 6 inches in diameter ; to the outer surface of this paper was glued a model of the chain of ossicles similar to the one used in the previous experiment ; a vibrating tuning-fork C' being placed in the interior of the tube and within a quarter of an inch of the paper, the sound was heard through the free end of the chain placed between the teeth for ten seconds ; when the sound ceased to be heard, a straight piece of wood was substituted, and the sound was not heard through it. II. Experiments illustrative of the influence of the articulations in the chain. Experiment 1. — Three pieces of wood, each about 5 inches long and half an inch in thickness, were separated from each other by pieces of india-rubber as thick as ordinary writing-paper, and they were then fastened together so as to assume the angular form pos- sessed by the chain of ossicles. The tuning-fork C' being placed at the free extremity of the chain, the other extremity being held between the teeth, it was found that the sound was heard as distinctly and for the same length of time, as when it passed through the chain formed of three portions glued together. Experiment 2. — When eight layers of the india-rubber were placed between each piece of wood, there was still very little difference in the intensity of the sound from that observed when it passed through the portions glued together. Experiment 3. — One, two, or three fingers having been placed between the first and second pieces of wood, and eight layers of india-rubber between the second and third, a very slight diminution in the intensity and duration of the sound was observed as compared with its passage through similar pieces when glued together. Experiment 4. — The back of the hand was placed in contact with the teeth, and the end of the vibrating fork C' was pressed against the palm ; the sound was heard very distinctly for several seconds ; and when it ceased to be heard, a piece of solid wood 3 inches long was substituted, through which the sound of the fork was again heard faintly for four seconds. The inference from the two series of experiments above detailed is, D2 36 that neither the variation of the plane existing in the chain of ossicles, nor the presence of the articulations, is sufficient to prevent the progress of sonorous undulations through this chain to the vestibule. The experiments and observations detailed above lead to the following conclusions : — 1 . That the commonly received opinion in favour of the sonorous undulations passing to the vestibule through the chain of ossicles is correct. 2. That the stapes, when disconnected from the incus, can still conduct sonorous undulations to the vestibule from the air. 3. So far as our present experience extends, it appears that in the human ear sound always travels to the labyrinth through two media, viz. through the air in the tympanic cavity to the cochlea, and through one or more of the ossicles to the vestibule. VI. " On the Electrical Discharge in vacua with an Extended Series of the Voltaic Battery." By JOHN P. GASSIOT, Esq., V.P.R.S. Received May 24, 1859. In a recent communication, since ordered for publication in the Philosophical Transactions, I described some experiments on the electrical discharge in a vacuum obtained by the absorption of carbonic acid with caustic potassa, and I showed that, when the dis- charge from an induction coil was passed through such a vacuum, the stratifications became altered in character and appearance as the potassa was more or less heated. I have also in a former paper (Phil. Trans. 1858, p. 1) shown that the stratified discharge can be obtained from the electrical machine. A description of an extended series of a water-battery was com- municated by me as far back as December 1843 (Phil. Trans. 1844, p. 39). This battery consists of 3520 insulated cells: some years had elapsed since it was last charged, and I found the zincs were very much oxidated ; on again charging it with rain-water, I ascer- tained that there was sufficient tension to give a constant succession of minute sparks between two copper discs attached to the terminals of the battery, and placed about -j-th of an inch apart. On at- taching the terminals of the battery to the wires in a carbonic acid 37 vacuum-tube inserted about 2 inches apart, I obtained a stratified discharge similar to that from an induction coil. The experiment was repeated with 400 series of Grove's nitric acid battery. In this case distinct sparks between two copper discs were obtained, and the luminous layers were shown in a peculiar and striking manner, thus proving that the induction coil is not necessary for the production of the striae, as in most of the experiments the only interruption of the battery circuit was through the vacuum- tube. I had another tube prepared, substituting for metallic points balls of gas-carbon. At first the stratified discharge was obtained as before, while little or no chemical action took place in the battery ; on heating the potassa, the character of the stratifications gradually changed, and suddenly a remarkably brilliant white discharge, also stratified, was observed ; intense chemical action was at the same time perceptibly taking place in the battery, and on breaking the circuit, the usual vivid electrical flame-discharge was developed at the point of disruption. The continuation of these experiments will necessarily occupy much time, involving, as they do, the charging of so extended a series of the nitric acid battery, and with the requisite care necessary for the proper insulation of each cell ; other phenomena were observed which require further verification, but I hope that after the recess the result which I hope to obtain may be of sufficient interest to form the subject of a future communication. VII. "Note on the Transmission of Radiant Heat through Gaseous Bodies." By JOHN TYNDALL, Ph.D., F.R.S. &c. Received May 26, 1859. Before the Royal Society terminates its present session, I am anxious to state the nature and some of the results of an investiga- tion in which I am now engaged. With the exception of the celebrated memoir of M. Pouillet on Solar Radiation through the atmosphere, nothing, so far as I am aware, has been published on the transmission of radiant heat through gaseous bodies. We know nothing of the effect even of air upon heat radiated from terrestrial sources. 38 The law of inverse squares has been proved by Melloni to be true for radiant heat passing through air, whence that eminent experimenter inferred that the absorption of such heat by the atmo- sphere, in a distance of 18 or 20 feet, is totally inappreciable. With regard to the action of other gases upon heat, we are not, so far as I am aware, possessed of a single experiment. Wishing to add to our knowledge in this important particular, I had a tube constructed, 4 feet long and 3 inches in diameter, and by means of brass terminations and suitable washers, I closed per- fectly the ends of the tube by polished plates of rock-salt. Near to one of its extremities, a T-piece is attached to the tube, one of whose branches can be screwed to the plate of an air-pump, so as to permit the tube to be exhausted ; while the gas to be operated on is admitted through the other branch of the T-piece. Such a tube can be made the channel of calorific rays of every quality, as the rock-salt transmits all such rays with the same facility. I first permitted the obscure heat emanating from a source placed at one end of the tube, to pass through the latter, and fall upon a thermo-electric pile placed at its other end. The tube contained ordinary air. When the needle of a galvanometer connected with the pile had come to rest, the tube was exhausted, but no change in the position of the needle was observed. A similar negative result was obtained when hydrogen gas and a vacuum were compared. Here I saw, however, that when a copious radiation was employed, and the needle pointed to the high degrees of the galvanometer, to cause it to move through a sensible space, a comparatively large diminution of the current would be necessary ; far larger, indeed, than the absorption of the air, if any, could produce : while if I used a feeble source, and permitted the needle to point to the lower degrees of the galvanometer, the total quantity of heat in action was so small, that the fraction of it absorbed, if any, might well be insensible. My object then was to use powerful currents, and still keep the needle in a sensitive position ; this was effected in the following manner : — The galvanometer made use of possessed two wires coiled side by side round the needle ; and the two extremities of each wire were connected with a separate thermo-electric pile, in such a manner that the currents excited by heat falling upon the faces of the two piles passed in opposite directions round the galvanometer. A source of 39 heat of considerable intensity was permitted to send its rays through the tube to the pile at its opposite extremity ; the deflection of the needle was very energetic. The second pile was now caused to ap- proach the source of heat until its current exactly neutralized that of the other pile, and the needle descended to zero. Here then we had two powerful forces in perfect equilibrium ; and inasmuch as the quantity of heat in action was very considerable, the absorption of a small fraction of it might be expected to produce a sensible effect upon the galvanometer-needle in its present position. When the tube was exhausted, the balance between the equal forces was destroyed, and the current from the pile placed at the end of the tube predominated. Hence the removal of the air had permitted a greater amount of heat to pass. On readmitting the air, the needle again descended to zero, indicating that a portion of the radiant heat was intercepted. Very large effects were thus obtained. I have applied the same mode of experiment to several gases and vapours, and have, in all cases, obtained abundant proof of calorific absorption. Gases vary considerably in their absorptive power — pro- bably as much as liquids and solids. Some of them allow the heat to pass through them with comparative facility, while other gases bear the same relation to the latter that alum does to other diather- manous bodies. Different gases are thus shown to intercept radiant heat in different degrees. I have made other experiments, which prove that the self- same gas exercises a different action upon different qualities of radiant heat. The investigation of the subject referred to in this Note is now in progress, and I hope at some future day to lay a full descrip- tion of it before the Royal Society. VIII. " Photochemical Researches."— Part IV. By ROBERT W. BUNSEN, For. Memb. R.S., and HENRY ENFIELD ROSCOE, Ph.D., Professor of Chemistry in Owens College, Man- chester. Received May 26, 1859. (Abstract.) In the three communications * which they have already made to the Royal Society upon the subject of photochemistry, the authors showed * Phil. Trans. 1857, pp. 355, 381 and 601. 40 that they have constructed a most delicate and trustworthy instrument by which to measure the chemical action of light, and by help of which they have been able to investigate the laws regulating this action. In the present memoir, the authors proceed, in the first place, to establish a general and absolute standard of comparison for the chemical action of light ; and in the second place, to consider the quantitative relations of the chemical action effected by direct and diffuse sunlight. They would endeavour, in this part of their research, to lay the foundation of a new and important branch of meteorological science, by investigating the laws which regulate the distribution, on the earth's surface, of the chemical activity ema- nating from the sun. The subject-matter of the present communication is divided under five heads : — 1. The comparative and absolute measurement of the chemical rays. 2. Chemical action of diffuse daylight. 3. Chemical action of direct sunlight. 4. Photochemical action of the sun, compared with that of a terrestrial source of light. 5. Chemical action of the constituent parts of solar light. The first essential for the measurement of photochemical actions, is the possession of a source of constant light. This the authors secured with a greater amount of accuracy than by the method de- scribed in their former communications, by employing a flame of pure carbonic oxide gas, burning from a platinum jet of 7 millims. in dia- meter, and issuing at a given rate, and under a pressure very slightly different from that of the atmosphere. The action which such a standard flame produces in a given time on the sensitive mixture of chlorine and hydrogen, placed at a given distance, is taken as the arbitrary unit of photochemical illumination. This action is, how- ever, not that which is directly observed on the scale of the instru- ment. The true action is only obtained by taking account of the absorption and extinction which the light undergoes in passing through the various glass-, water-, and mica-screens placed between the flame and the sensitive gas. These reductions can be made by help of the determinations given in Part III. of these Researches, as well as by experiments detailed in the present Part. When these sources 41 of error are eliminated, it is possible, by means of this standard flame, to reduce the indications of different instruments to the same unit of luminous intensity, and thus to render them comparable. For this purpose, the authors define the photometric unit for the chemically active rays, as the amount of action produced in one minute, by a standard flame placed at a distance of one metre from the normal mixture of chlorine and hydrogen; and they determine experimentally for each instrument the number of such units which correspond to one division on the scale of the instru- ment. By multiplying the observed number of divisions by the number of photometric units equal to one division, the observations are reduced to a comparable standard. It is proposed to call this unit a chemical unit of light, and ten thousand of them one chemical degree of light. According to this standard of measurement, the chemical illu- mination of a surface, that is, the amount of chemically active light which falls perpendicularly on the plane surface, can be obtained. It has thus been found that the distance to which two flames of coal-gas and carbonic oxide, each fed with gas at the rate of 4*105 cubic cent, per second, must be removed from a plane^surface, in order to effect upon it an amount of chemical action represented by one degree of light, was, in the case of the coal-gas flame, 0'929 metre, in that of carbonic oxide 0'561 metre. The chemical illuminating power, or chemical intensity, of various sources of light, measured by the chemical action effected by these sources at equal distances and in equal times, can also be expressed in terms of this unit of light ; and these chemical intensities may be compared with the visible light-giving intensities. In like manner, the authors define chemical brightness as the amount of light, measured photochemi- cally, which falls perpendicularly from a luminous surface upon a physical point, divided by the apparent magnitude of the surface ; and this chemical brightness of circles of zenith-sky of different sizes has been determined. Experiment shows that the chemical bright- ness of various sized portions of zenith- sky, not exceeding 0'00009 of the total heavens, is the same ; or, that the chemical action effected is directly proportional to the apparent magnitude of the illuminating surface of zenith-sky. It is, however, important to express the photochemical actions 42 not only according to an arbitrary standard, but in absolute measure, in units of time and space. This has been done by determining the absolute volume of hydrochloric acid formed by the action of a given source of light during a given space of time. For this pur- pose, we require to know — tf=the volume of hydrochloric acid formed by the unit of light. k=ihe thickness of sensitive gas through which the light passed. 5= the surface-area of the insulated gas. a=the coefficient of extinction of the chlorine and hydrogen for the light employed. /=the number of observed units of light in the time t. When these values are known, the volume of hydrochloric acid which would be formed in the time t, by the rays falling perpendi- cularly on the unit of surface, if the light had been completely extinguished by passing through an infinitely extended atmosphere of dry chlorine and hydrogen, is found from the expression V— v l -'' In this way the chemical illumination of any surface may be ex- pressed by the height of the column of hydrochloric acid which the light falling upon that surface would produce, if it passed through an unlimited atmosphere of chlorine and hydrogen. This height, measured in metres, the authors propose to call a Light- metre. The chemical action of the solar rays can be expressed in light-metres ; and the mean daily, or annual height thus obtained, dependent on latitude and longitude, regulates the chemical climate of a place, and points the way to relations for the chemical actions of the solar rays, which in the thermic actions are already repre- sented by isothermals, isotherals, &c. In order to determine the chemical action exerted by the whole diffuse daylight upon a given point on the earth's surface, the authors were obliged to have recourse to an indirect method of ex- perimenting, owing to the impossibility of measuring the whole action directly, by means of the sensitive mixture of chlorine and hydrogen. For the purpose of obtaining the wished-for result, the chemical action proceeding from a portion of sky at the zenith, of known magnitude, was determined in absolute measure, and then, 43 by means of a photometer, whose peculiar construction can only be understood by a long description, the relation between the visible illuminating power of the same portion of zenith sky and that of the total heavens was determined. As, in the case of lights from the same source but of different degrees of intensity, the chemical actions are proportional to the visible illuminating effects, it was only necessary, in order to obtain the chemical action produced by the total diffuse light, to multiply the chemical action of the zenith portion of sky by the number representing the relation between the visible illumination of the total sky and that of the same zenith portion. The laws according to which the chemical rays are dispersed by the atmosphere can only be ascertained from experiments made when the sky is perfectly cloudless. In the determinations made with this specially-arranged photometer, care was therefore taken that the slightest trace of cloud or mist was absent, and the relation between the visible illuminating effect of a portion of sky at the zenith and that of the whole visible heavens, was determined for every half-hour from sunrise to sunset ; the observations being made at the summit of a hill near Heidelberg, from which the horizon was perfectly free. The amount of chemical illumination which a point on the earth's surface receives from the whole heavens, depends on the height of the sun above the horizon and on the transparency of the atmo- sphere. If the atmospheric transparency undergoes much change when the sky is cloudless, a long series of experiments must be made before the true relations of atmospheric extinction of the chemical rays can be arrived at. The authors believe, however, founding their opinion on the statement of Seidel in his classical research on the luminosity of the fixed stars, that the alterations in the air's transparency with a cloudless sky are very slight ; and they there- fore think themselves justified in considering the chemical illumi- nation of the earth's surface, on cloudless days, to be represented simply as a function of the sun's zenith distance. Although, from the comparatively small number of experiments which have been made, owing to the difficulty of securing perfectly cloudless weather, the constants contained in the formulae cannot lay claim to any very great degree of accuracy, the authors believe that the numbers ob- 44 taincd are sufficient to enable them to determine the relation accord- ing to which the chemical energy proceeding from the sun is diffused over the earth when the sky is unclouded. From a series of observations made on June 6, 1858, the relation between the amount of light optically measured falling from the whole sky, and the amount (taken as unity) which, at the same time, falls from a portion of zenith sky equal to } fa Oth of the whole visible heavens, has been calculated for every degree of sun's zenith distance from 20° to 90°; the results being tabulated, and also represented graphically. These numbers, multiplied by the che- mical light proceeding from the same portion of zenith sky for the same zenith distances, must give the chemical action effected by the whole diffuse daylight. The amount of chemical light which falls from the zenith portion of sky is, however, the chemical brightness of that portion of sky. This chemical brightness has been deter- mined, by the chlorine and hydrogen photometer, on various days, and at different hours, when the sky was perfectly cloudless. A table contains the chemical action, expressed in degrees of light, which is effected on the earth's surface by .a portion of zenith sky equal in area to 101QQth of the whole visible heavens, under the cor- responding sun's zenith distances from 20° to 90°. A curve repre- senting the relation between the action and the height of the sun, shows that although the single observations were made on different years and at different times of the year and day, they all agree closely amongst themselves, and hence another proof is gained of the slight effect which variation in the air's transparency produces ; and it is seen that the total chemical action effected by the diffuse light of day may be represented as a function of the sun's zenith distance. The numbers thus obtained have only to be multiplied by the corresponding numbers of the former table, in order to give the chemical action effected by the total diffuse light of day for zenith distances from 20° to 90°. A table and graphic representation of these numbers is given. Knowing the relation between the sun's altitude and the chemical action, the chemical illumination effected each minute at any given locality at a given time may be calculated ; this calculation has been made for a number of places for each hour on the vernal equinox, tables and curves representing the alteration 45 of luminous intensity with the height of the sun at these places being given. From these data it is possible also to calculate the action produced by the whole diffuse light, not only for each minute, but during any given space of time. For the following places the amount of che- mical illumination expressed in degrees of light which falls from sun- rise to sunset on the vernal equinox, is — Melville Island , 10590 Reykiavik 15020 St. Petersburg 1 6410 Manchester 18220 Heidelberg 19100 Naples 20550 Cairo 21670 Experiment has shown that clouds exert the most powerful influ- ence in reflecting the chemical rays ; when the sky is partially covered by light white clouds, the chemical illumination is more than four times as intense as when the sky is clear. Dark clouds and mists, on the other hand, absorb almost all the chemically active rays. The chemical action of the direct sunlight was determined by allowing a known fractional portion of the solar rays to fall perpen- dicularly on the insolation vessel of the chemical photometer. The solar rays reflected from the mirror of a Silbermann's heliostat were passed through a fine opening of known area into the dark room, and a large number of reductions and corrections had to be made in order to obtain, from the direct observations, the action, expressed in degrees of light, which the sun shining directly upon the apparatus would have produced if no disturbing influences had interfered. This action of direct sunshine was determined on three different cloudless days for various altitudes of the sun. As the sun approached the zenith the observed action rapidly increased ; thus at 7h 9' A.M., on September 15, 1858, when the sun's zenith distance was 76° 30', the reduced action amounted to 5 '5 degrees of light, whilst at 9h 14' A.M. on the same day, the zenith distance being 58° 11', the action reached 67*6. This increase in the sun's illuminating power is owing to the diminution in length of the 46 column of air through which the rays pass. If we suppose the atmosphere to be throughout of the density corresponding to a pressure 0'76 and a temperature 0°, and consider it as a horizontal layer, and if A represent the action effected before entrance into the atmosphere, the action, when the ray has passed through a thickness of atmosphere = I, is represented by W0=A10~a/> where - signifies the depth of atmosphere through which the ray has to pass to be reduced to J^th of its original intensity, and where I is dependent on the atmosphere's perpendicular height =A, and the sun's zenith distance 0. The numerical values of A a and I may be calculated from the direct observations, and hence the action Wa effected at any other zenith distance 0t, and under a pressure P^ is found from the equation -<*h PI W1=A10 C08^po, where P0 represents the atmospheric pressure under which A and a are calculated. A comparison between the actions Wx thus obtained, and those, W0, found by experiment, shows as close an agreement as could be expected where the observational errors are necessarily so large. From these experiments it is seen, that if the sun's rays were not weakened by passage through the atmosphere, they would produce an illumination represented by 318 degrees of light; or they would effect a combination in one minute on a surface on which they fell perpendicularly, of a column of hydrochloric acid 35 '3 metres in height, assuming that the rays are extinguished by passing through an infinitely extended atmosphere of chlorine and hydrogen. By help of the above formula, it is also found that the sun's rays, after they have passed in a perpendicular direction through the atmo- sphere to the sea's level, under a mean pressure of 0*76 metre, only effect an action of 14*4 light-metres, or that under these conditions nearly two-thirds of their chemical activity have been lost by extinc- tion and dispersion in the atmosphere. The total chemical action emanating from the sun during each minute is therefore represented by a column of hydrochloric acid 35 metres in height, and having an area equal to the surface of a sphere whose diameter is the mean 47 distance of the earth to the sun. Or the light which the sun radiates into space during each minute of time represents a chemical energy, by means of which more than 25 billions of cubic miles of chlorine and hydrogen may be combined to form hydrochloric acid. In like manner the amounts of chemical action have been calculated, which the sun's rays, undiminished by atmospheric extinction, pro- duce at the surface of the chief planets. The first column of num- bers gives the mean distances of the planets from the sun, the second contains the chemical action expressed in light-metres. Mercury 0-387 235-4 light-metres. Venus 0723 67'5 Earth 1-000 35-3 Mars 1-524 15-2 Jupiter 5-203 1-3 Saturn 9'539 0'4 „ Uranus 19-183 0-1 Neptune 30-040 0-04 By aid of the formula already given, the authors have been enabled to calculate the chemical action effected each minute by the direct sunlight, not only at different points on the earth's surface, but at various heights above the sea's level. Both these series of relations are tabulated, and graphically represented. On comparing the numbers and curves giving the action of the total diffuse light with those of the direct solar light, the singular fact becomes apparent, that from the North Pole to latitudes below that of Petersburg, the chemical action proceeding from the diffuse light is, throughout the day on the vernal equinox, greater than that effected by the direct sunlight ; and that in lower latitudes, down to the Equator, the same phenomenon is observed, if not for the whole, still for a portion of the day. It is further seen, that for all places, and on every day when the sun rises to a certain height above the horizon, there is a moment at which the chemical action of the diffused light is exactly equal to that of the direct sunlight. The times at which these phases of equal chemical illumination occur can be calculated ; they can also be actually determined, by allowing the direct sunlight alone, and the whole diffuse daylight alone, to fall at the same time upon two pieces of the same sensitized photographic paper; the 48 period at which both papers become equally blackened, gives the time of the phase of equal chemical intensity. Experiment proved not only that these points of equality which the theory requires actually occur, but also that the agreement between the calculated and observed times of occurrence of the phases is very close, giving proof that the data upon which the theory is founded are substan- tially correct. The formula, by help of which the chemical action of the direct sunlight eifected at any place during any given time can be calcu- lated, is next developed, and the direct solar action at the following places calculated for the vernal equinox from sunrise to sunset. Column I. gives the action of the direct sunlight during the whole day, expressed in degrees of light ; Column II. the action for the same time eifected by both direct and diffuse solar light ; and Column III. the same action expressed in light-metres : — I. II. III. Melville Island 1 196 1 1790 1306 metres. Reykiavik 5964 20980 2324 „ St. Petersburg 8927 25340 2806 „ Manchester 14520 32740 3625 „ Heidelberg ... 18240 37340 4136 „ Naples 26640 47190 5226 „ Cairo 36440 581 10 6437 „ The authors next proceed to examine the chemical brightness of the sun compared with a terrestrial source of light. For this pur- pose the intensely bright light produced by a wire of magnesium burning in the air was employed. Experiment showed that the chemical intensity of the sunlight, undiminished by atmospheric extinction, is 128 times greater than that from a surface of incan- descent magnesium of like apparent magnitude ; or that burning magnesium effects the same chemical illumination as the sun when 9° 53' above the horizon, supposing of course that both luminous sources present to the illuminated surface the same apparent magni- tude. A totally different relation was found to exist between the visible illuminating power, i. e. the effect produced on the eye, of the two sources in question. Thus, when the sun's zenith distance was 67° 22f, the chemical brightness of that source was 36*6 times, but the visible brightness 525 times as large as that of the terrestrial source of light. In the last section of this communication the chemical action of the constituent parts of the solar spectrum is investigated. The sun's rays were reflected from a Silbermann's heliostat, and after passing through a narrow slit, they were decomposed by two quartz prisms. The spectrum thus produced was allowed to fall upon a white screen covered with a solution of quinine, and any desired por- tion of the rays could be measured by a finely-divided scale, and the position noted by observation of the distances from the fixed lines. For the purpose of identifying the fixed lines in the lavender rays, the authors were, by the kindness of Mr. Stokes, allowed the use of an unpublished map of the most refrangible portion of the spectrum, prepared by that gentleman. As the various components of white light are unequally absorbed by the atmosphere, it was obviously necessary to conduct all the measurements so quickly after one another, that no appreciable difference in the thickness of the column of air passed through should occur. This has been accomplished, and a series of exact measurements of the chemical actions of the spectrum for one particular zenith- distance of the sun obtained. The action on the sensitive gas shows the existence of several maxima of chemical intensity in the spectrum. Between the lines G in the indigo and H in the violet the greatest action was observed, whilst another maximum was found to lie near the line I in the ultra-violet rays. Towards the red or least refran- gible end of the spectrum, the action became imperceptible about the line D in the orange, but at the other end of the spectrum the action was found to extend as far as Stokes' s line U, or to a distance from the line H greater than the total length of the ordinary visible spec- trum. Tables and curves representing the action are given. VOL. x. 50 IX. " On the Occurrence of Flint-implements, associated with the Remains of Extinct Mammalia, in Undisturbed Beds of a late Geological Period." By JOSEPH PRESTWICH, Esq., F.R.S., F.G.S. &c. Received May 26, 1859. (Abstract.) The author commences by noticing how comparatively rare are the cases even of the alleged discovery of the remains of man or of his works in the various superficial drifts, notwithstanding the ex- tent to which these deposits are worked ; and of these few cases so many have been disproved, that man's non-existence on the earth until after the latest geological changes, and the extinction of the Mammoth, Tichorhine Rhinoceros, and other great mammals, had come to be considered almost in the light of an established fact. Instances, however, have from time to time occurred to throw some doubt on this view, as the well-known cases of the human bones found by Dr. Schmerling in a cavern near Liege, — the remains of man, instanced by M. Marcel de Serres and others in several caverns in France, — the flint-implements in Kent's Cave, — and many more. Some uncertainty, however, has always attached to cave-evidence, from the circumstance that man has often inhabited such places at a comparatively late period, and may have disturbed the original cave-deposit ; or, after the period of his residence, the stalagmitic floor may have been broken up by natural causes, and the remains above and below it may have thus become mixed together, and afterwards sealed up by a second floor of stalagmite. Such instances of an imbedded broken stalagmitic floor are in fact known to occur ; at the same time the author does not pretend to say that this will explain all cases of intermixture in caves, but that it lessens the value of the evidence from such sources. The subject has, however, been latterly revived, and the evidence more carefully sifted by Dr. Falconer ; and his preliminary reports on the Brixham Cave*, presented last year to the Royal Society, announcing the carefully determined occurrence of worked flints * On the 4th of May, this year, Dr. Falconer further communicated to the Geo- logical Society some similar facts, though singularly varied, recently discovered by him in the Maccagnone Cave near Palermo. — See Proc. Geol. Soc. 51 mixed indiscriminately with the bones of the extinct Cave Bear and the Rhinoceros, attracted great and general attention amongst geo- logists. This remarkable discovery, and a letter written to him by Dr. Falconer on the occasion of his subsequent visit to Abbeville last autumn, instigated the author to turn his attention to other ground, which, from the interest of its later geological phenomena alone, as described by M. Buteux in his " Esquisse Geologique du Departement de la Somme," he had long wished and intended to visit. In 1849 M. Boucher de Perthes, President of the "Socie'te d' Emulation" of Abbeville, published the first volume of a work entitled "Antiquites Celtiques et Antediluviennes," in which he an- nounced the important discovery of worked flints in beds of undis- turbed sand and gravel containing the remains of extinct mammalia. Although treated from an antiquarian point of view, still the state- ment of the geological facts by this gentleman, with good sections by M. Ravin, is perfectly clear and consistent. Nevertheless, both in France and in England, his conclusions were generally considered erroneous ; nor has he since obtained such verification of the pheno- mena as to cause so unexpected a fact to be accepted by men of science. There have, however, been some few exceptions to the general incredulity. The late Dr. Rigollot, of Amiens, urged by M. Boucher de Perthes, not only satisfied himself of the truth of the fact, but corroborated it, in 1855, by his "Memoire sur des Instruments en Silex trouves a St. Acheul." Some few geologists suggested further inquiry ; whilst Dr. Falconer, himself convinced by M. de Perthes' explanations and specimens, warmly engaged Mr. Prestwich to examine the sections. The author, who confesses that he undertook the inquiry full of doubt, went last Easter, first to Amiens, where he found, as de- scribed by Dr. Rigollot, the gravel-beds of St. Acheul capping a low chalk-hill a mile S.E. of the city, about 100 feet above the level of the Somme, and not commanded by any higher ground. The following is the succession of the beds in descending order : — Average thickness. 1. Brown brick-earth (many old tombs and some coins}, with an irregular bed of flint-gravel. No organic remains. 10 to 15 ft. Divisional plane between 1 and 2a very uneven and indented. 2a. Whitish marl and sand with small chalk debris. Land E2 52 Average thickness. and fresh water shells (Lymnea, Succinea, Helix, Bithynia, Planorbis, Pupa, Pisidium, and Ancylus> all of recent species) are common, and mammalian bones and teeth are occasionally found ................................................ 2 to 8ft. 26. Coarse subangular flint-gravel,— white with irregular ochreous and ferruginous seams, — with tertiary flint peb- bles and small sandstone blocks. Remains of shells as above, in patches of sand. Teeth and bones of the ele- phant, and of a species of horse, ox, and deer, — generally near base. This bed is further remarkable for containing worked flints (" Haches " of M. de Perthes, and " Langues de Chat" of the workmen) .................................... 6 to 12 ft. Uneven surface of chalk. The flint-implements are found in considerable numbers in 26. On his first visit, the author obtained several specimens from the workmen, but he was not successful in finding any himself. On his arrival, however, at Abbeville, he received a message from M. Pinsard of Amiens, to whose cooperation he expresses himself much indebted, to inform him that one had been discovered the following day, and was left 2/1 situ for his inspection. On returning to the spot, this time with his friend Mr. Evans, he satisfied himself that it was truly in situ, 1 7 feet from the surface, in undisturbed ground, and he had a photographic sketch of the section taken*. Dr. Rigollot also mentions the occurrence in the gravel of round pieces of hard chalk, pierced through with a hole, which he considers were used as beads. The author found several, and recognized in them a small fossil sponge, the Coscinopora ylobularis, D'Orb., from the chalk, but does not feel quite satisfied about their artificial dressing. Some specimens do certainly appear as though the hole had been enlarged and completed. The only mammalian remains the author here obtained, were some specimens of the teeth of a horse, but whether recent or ex- tinct, the specimens were too imperfect to determine ; and part of the tooth of an elephant (Elephas primigeniusl). In the gravel-pit of St. Roch, 1| ™ile distant, and on a lower level, mammalian * On revisiting the pit, since the reading of this paper, in company with several geological friends, the author was fortunate to witness the discovery and extraction by one of them, Mr. J. W. Flower, of a very perfect and fine specimen of flint-implement, in a seam of ochreous gravel, 20 feet beneath the surface. They besides obtained thirty-six specimens from the workmen. — June, 1859. 53 remains are far more abundant, and include Elephas primige- nius, Rhinoceros tichorhinus, Cervus somonensis. Bos priscus, and Equus* ; but the workmen said that no worked flints were found there, although they are mentioned by Dr. Rigollot. At Abbeville the author was much struck with the extent and beauty of M. Boucher de Perthes' collection. There were many forms of flints, in which he, however, failed to see traces of design or work, and which he should only consider as accidental ; but with regard to those flint-instruments termed "axes" ("baches") by M. de Perthes, he entertains not the slightest doubt of their artificial make. They are of two forms, generally from 4 to 1 0 inches long : the outlines of two specimens are represented in the following dia- gram. They are very rudely made, without any ground surface, Fig. 2. Fig. 1. Front section. Side section. Side section. One-third the natural size. Front section. and were the work of a people probably unacquainted with the use of metals. These implements are much rarer at Abbeville than at Amiens, fig. 1 being the common form at the former, and fig. 2 at the latter place. The author was not fortunate enough to find any * To this list the author has to add the Hippopotamus, of which creature four fine tusks were obtained on this last visit. 54 specimens himself; but from the experience of M. de Perthes, and the evidence of the workmen, as well as from the condition of the specimens themselves, he is fully satisfied of the correctness of that gentleman's opinion, that they there also occur in beds of undisturbed sand and gravel. At Moulin Quignon, and at St. Gilles, to the S.E. of Abbeville, the deposit occurs, as at St. Acheul, on the top of a low hill, and consists of a subangular, ochreous and ferruginous flint-gravel, with a few irregular seams of sand, 12 to 15 feet thick, reposing upon an uneven surface of chalk. It contains no shells, and very few bones. M. de Perthes states that he has found fragments of the teeth of the elephant here. The worked flints and the bones occur generally in the lower part of the gravel. In the bed of gravel also on which Abbeville stands, a number of flint-implements have been found, together with several teeth of the Elephas primigenius, and, at places, fragments of freshwater shells. The section, however, of greatest interest is that at Menchecourt, a suburb to the N.W. of Abbeville. The deposit there is very distinct in its character ; it occurs patched on the side of a chalk hill, which commands it to the northward ; and it slopes down under the peat-beds of the valley of the Somme to the southward. The deposit consists, in descending order, of — Average thickness. 1. A mass of brown sandy clay, with angular fragments of flints and chalk rubble. No organic remains. Base very irregular and indented into bed No. 2 2 to 12 ft. 2. A light-coloured sandy clay (" sable gras " of the work- men), analogous to the loess, containing land shells, Pupa, Helix, Clawilia of recent species. Flint-axes and mammalian remains are said to occur occasionally in this bed 8 to 25 ft. 3. White sand (" sable aigre"), with 1 to 2 feet of subangular flint-gravel at base. This bed abounds in land and fresh- water shells of recent species of the genera Helix, Succinea, Cyclas, Pisidium, Valvata, Bithynia, and Planorbis, to- gether with the marine Buccinum undatum, Cardium edule, Tellina solidula, and Purpura lapillus. The author has also found the Cyrena consobrina and Littorina rudis. With them are associated numerous mammalian remains, and, it is said, flint-implements 2 to 6ft. 4. Light-coloured sandy marl, in places very hard, with Helix, Zonites, Succinea, and Pupa. Not traversed 3 + 55 The Mammalian remains enumerated by M. Buteux from this pit are, — Elephas primigenius, Rhinoceros tichorhinus, Cervus somo- nensis ?, Cervus tarandus priscus, Ursus spelceus, Hyaena spelcea, Bos primigenius, Equus adamaticus, and a Felis. It would be essential to determine how these fossils are distributed — which occur in bed No. 2, and which in bed No. 3. This has not hitherto been done. The few marine shells occur mixed indiscriminately with the freshwater species, chiefly amongst the flints at the base of No. 3. They are very friable and somewhat scarce. It is on the top of this bed of flints that the greater number of bones are found, and also, it is said, the greater number of flint-implements. The author, however, only saw some long flint flakes (considered by M. de Perthes as flint knives) turned out of this bed in his presence, but the workmanship was not very clear or apparent ; still it was as much so as in some of the so-called flint knives from the peat -beds and barrows. There are specimens, however, of true implements ("baches") in M. de Perthes' collection from Menchecourt ; one noticed by the author was from a depth of 5, and another of 7 metres. This would take them out from bed No. 1, but would leave it uncertain whether they came from No. 2 or No. 3. From their general appearance, and traces of the matrix, the author would be disposed to place them in bed No. 2, but M. de Perthes believes them to be from No. 3 ; if so, it must have been in some of the sub- ordinate clay seams occasionally intercalated in the white sand. Besides the concurrent testimony of all the workmen at the dif- ferent pits, which the author after careful examination saw no reason to doubt, the flint-implements ("haches") bear upon them- selves internal evidence of the truth of M. de Perthes' opinion. It is a peculiarity of fractured chalk flints to become deeply and per- manently stained and coloured, or to be left unchanged, according to the nature of the matrix in which they are imbedded. In most clay beds they become outside of a bright opaque white or porcelainic ; in white calcareous or siliceous sand their fractured black surfaces remain almost unchanged ; whilst in beds of ochreous and ferru- ginous sands, the flints are stained of the light yellow and deep brown colours so well exhibited in the common ochreous gravel of the neighbourhood of London. This change is the work of very long time, and of moisture before the opening out of the beds. Now in 56 looking over the large series of flint-implements in M. de Perthes' col- lection, it cannot fail to strike the most casual observer that those from Menchecourt are almost always white and bright, whilst those from Moulin Quignon have a dull yellow and brown surface ; and it may be noticed that whenever (as is often the case) any of the matrix adheres to the flint, it is invariably of the same nature, texture, and colour as that of the respective beds themselves. In the same way at St. Acheul, where there are beds of white and others of ochreous gravel, the flint-implements exhibit corresponding variations in colour and adhering matrix ; added to which, as the white gravel contains chalk debris, there are portions of the gravel in which the flints are more or less coated with a film of deposited carbonate of lime ; and so it is with the flint-implements which occur in those portions of the gravel. Further, the surface of many specimens is covered with fine dendritic markings. Some few implements also show, like the fractured flints, traces of wear, their sharp edges being blunted. In fact, the flint-implements form just as much a constituent part of the gravel itself, — exhibiting the action of the same later influences and in the same force and degree, — as the rough mass of flint frag- ments with which they are associated. With regard to the geological age of these beds, the author refers them to those usually designated as post-pliocene, and notices their agreement with many beds of that age in England. The Menche- court deposit much resembles that of Fisherton near Salisbury ; the gravel of St. Acheul is like some on the Sussex coast ; and that of Moulin Quignon resembles the gravel at East Croydon, Wandsworth Common, and many places near London. The author even sees reason, from the general physical phenomena, to question whether the beds of St. Acheul and Moulin Quignon may not possibly be of an age one stage older than those of Menchecourt and St. Roch ; but before that point can be determined, a more extended knowledge of all the organic remains of the several deposits is indispensable. The author next proceeds to inquire into the causes which led to the rejection of this and the cases before mentioned, and shows that in the case of M. de Perthes' discovery, it was in a great degree the small size and indifferent execution of the figures and the introduction of many forms about which there might reasonably be a difference of opinion ; — in the case of the arrow-heads in Kent's Cave a hidden error was merely suspected ; — and in the case of the Liege cavern he considers that the question was discussed on a false issue. He therefore is of opinion that these and many similar cases require reconsideration ; and that not only may some of these prove true, but that many others, kept back by doubt or supposed error, will be forthcoming. One very remarkable instance has already been brought under the author's notice by Mr. Evans since their return from France. In the 13th volume of the 'Archseologia,' published in 1800, is a paper by Mr. John Prere, F.R.S. and F.S.A., entitled "An Account of Flint- Weapons discovered at Hoxne in Suffolk," wherein that gentle- man gives a section of a brick-pit in which numerous flint-imple- ments had been found, at a depth of 1 1 feet, in a bed of gravel con- taining bones of some unknown animal ; and concludes from the ground being undisturbed and above the valley, that the specimens must be of very great antiquity, and anterior to the last changes of the surface of the country,-*-a very remarkable announcement, hitherto overlooked. The author at once proceeded in search of this interesting locality, and found a section now exposed to consist of — feet. 1. Earth and a few flints 2 2. Brown brick-earth, a carbonaceous seam in middle and one of gravel at base ; no organic remains. The workmen stated that two flint-implements (one of which they shortly picked up in the author's presence) had been found about 10 feet from the surface during the last winter 12 3. Grey clay, in places carbonaceous and in others sandy, with recent land and freshwater shells (Planorbis, Falvata, Succinea, Pisi- dium, Helix, and Cyclas) and bones of Mammalia 4 4. Small subangular flint-gravel and chalk pebbles 2£ 5. Carbonaceous clay (stopped by water) ...., ^-j- The weapons referred to by Mr. Frere are described by him as being found abundantly in bed No. 4 ; but at the spot where the work has now arrived, this bed is much thinner, and is not worked. In the small trench which the author caused to be dug, he found no remains either of weapons or of bones. He saw, however, in the collection of Mr. T. E. Amyot, of Diss, specimens of the weapons, also an astragalus of the elephant from, it was supposed, this bed, 58 and, from bed No. 3, the teeth of a horse, closely resembling those from the elephant-bed of Brighton. The specimens of the weapons figured by Mr. Frere, and those now in the British Museum and elsewhere, present a singular simi- larity in work and shape to the more pointed forms from St. Acheul. One very important fact connected with this section, is that it shows the relative age of the bone and implement-bearing beds. They form a thin lacustrine deposit, which seems to be superimposed on the Boulder Clay, and to pass under a bed of the ochreous sand and flint-gravel belonging to the great and latest drift-beds of the district. The author purposely abstains for the present from all theoretical considerations, confining himself to the corroboration of the facts : — 1 . That the flint-implements are the work of man. 2. That they were found in undisturbed ground. 3. That they are associated with the remains of extinct Mammalia. 4. That the period was a late geological one, and anterior to the surface assuming its present outline, so far as some of its minor features are concerned. He does not, however, consider that the facts, as they at present stand, of necessity carry back Man in past time more than they bring forward the great extinct Mammals towards our own time, the evidence having reference only to relative and not to absolute time ; and he is of opinion that many of the later geological changes may have been sudden or of shorter duration than generally considered. In fact, from the evidence here exhibited, and from all that he knows regarding drift phenomena generally, the author sees no reason against the conclusion that this period of Man and the ex- tinct Mammals — supposing their contemporaneity to be proved — was brought to a sudden end by a temporary inundation of the land; on the contrary, he sees much to support such a view on purely geological considerations. The paper concludes with a letter from Mr. John Evans, F.S.A. and F.G.S., regarding these implements from an antiquarian rather than a geological point of view, and dividing them into three classes : — 1 . Flint flakes, — arrow-heads or knives. 2. Pointed weapons truncated at one end, and probably lance or spear heads (fig. 2). 59 3. Oval or almond-shaped implements with a cutting edge all round, possibly used as sling-stones or as axes (fig. 1). Mr. Evans points out, that in form and workmanship those of the two last classes differed essentially from the implements of the so- called Celtic period, which are usually more or less ground and polished, and cut at the wide and not the narrow end ; and that had they been found under any circumstances, they must have been regarded as the work of some other race than the Celts, or known aboriginal tribes. He fully concurs with Mr. Prestwich, that the beds of drift in which they were found were entirely undisturbed. X. " Observations on the Discovery in various Localities of the Remains of Human Art mixed with the Bones of Extinct Races of Animals." By CHARLES BABBAGE, Esq., M.A., P.R.S. &c. Received May 26, 1859. Statements have recently been made relative to the discovery of works of human art occurring in a breccia amongst bones of ancient animals, hitherto supposed to have been extinct long anterior to the existence of our race. These observations are supposed by some to prove the great antiquity of the human race ; whilst others, equally competent to form an opinion, admit that the intermixture of such remains presents a most perplexing mystery. Whatever may be the result of yet unpublished or of future and more extensive observations, it is certainly premature to assign this great antiquity to our race, as long as the occurrence of such mix- tures can be explained by known causes admitted to be still in action. Two places have recently been pointed out in which such mixtures are stated to occur : — 1st, certain localities in France ; 2nd, certain caves in Sicily. The latter have been visited by Dr. Falconer, and as the information respecting them which we at present possess, though small, is yet much more definite than what is known of the French locality, my explanations will chiefly relate to the latter. It is stated that one of the Sicilian caves has its sides perforated by marine animals. That on penetrating the stalactitical incrustation covering the 60 roof of the cavern, and detaching fragments, it was found to consist of a breccia of bones of animals long extinct, mixed with fragments of flint or stone, bearing evident traces of human art. In order to explain these circumstances, it is only necessary to admit the upheaval of the land and the occurrence of torrents. Fig. 1. 1st Period. — Let us suppose two caverns, a lower, A, and an upper, B C, communicating with each other by a long rent or pipe P. This pipe may be supposed of any height, sufficient when filled with water to produce the required force. The lower cavern is supposed to be nearly at the level of the sea. Fig. 2. Pholades and other marine animals will perforate or attach them- selves to the bottom and sides of the cavern, and if the sea entirely 61 fill it : the roof, too, or at least that portion adjacent to the mouth of the cavern, may be similarly affected. The rocks in which these caverns occur may be of any geological age. 2nd Period. — By the gradual or quick upheaval of the strata in which these caverns occur, they may become dry. During the rising, or at a later period, fragments of rock may have accumulated at the open mouth of the lower cavern, and thus have stopped up its entrance, leaving the roof, sides, and floors bearing evident traces of having been an ocean cave. 3rd Period. — Ages may have elapsed during which other strata may have been depositing in other portions of our globe. But ultimately the earth became inhabited by those ancient, but now extinct mammalia, whose remains abound in its caverns. Fig. 3. 4th Period. — Ages may again have intervened when man, in his first rude state of existence, entering this deserted den through the opening its former occupants had used, might have been glad to shelter himself from an inclement climate in this bone-house of a more ancient world. During this period traces of man's skill would probably be left within his miserable abode ; pottery, if he possessed the art ; char- coal or charred wood, if he were acquainted with fire ; rude cutting instruments of flint or other hard stone, perhaps spear or arrow- heads. 62 Fig. 4 represents the caverns at the end of the fourth period. Fig. 4. 5th Period. — Torrents entering by the aperture at C, might now have swept through the upper cavern, perhaps at successive intervals of time. The effect of such torrents would be to wash from the sloping floor of the upper cavern, the mixed remains of animal and human life, together with the earliest traces of human art. In some of these catastrophes, the workman, as well as his work, may have been entombed together in the lower cavern. Fig. 5. Thus in the course of time the whole of the lower cavern may have been filled up even to the roof. This state is represented in fig. 5. 63 The effect of infiltration through the roof would now cement into a breccia the mingled remnants from the upper chamber, and enclose them, as it were, in a marble monument, in their new, though not their latest resting-place. But the infiltration proceeding from the roof would act first, and most powerfully, in cementing the upper part of the intruded mass. The lower portion would be less consolidated, and therefore less capable of resisting any pressure from above. 6th Period. — In the progress of time, some torrent of extra- ordinary magnitude may have penetrated through the upper cavern, and, filling the channel or pipe P, have acted by its hydrostatic pressure on the semi-consolidated matter in the lower one. As the water accumulated in the pipe, the pressure would become immense, and ultimately the materials included in the lower cavern would give way at their point of least resistance. This would probably be towards the middle or bottom of the original entrance. The first sudden rush would probably clear out the greater part of the con- tents of the lower cavern, leaving, however, — 1st. Those portions attached to the roof by the infiltrated matter. 2nd. Those portions on the floor more consolidated by pressure than the middle which gave way ; and also other portions of the loose rubbish which the form of the floor at the entrance of the cave might have intercepted in its course. After this reopening of the lower cavern, the access of air would accelerate evaporation from its roof, and that portion of the breccia still adhering to it would gradually acquire the external coating of stalactite which usually occurs in caves. In the meantime the dropping from the roof, falling upon the floor, might also contribute to consolidate the remaining fragments, and, although more slowly, cover the whole of them with a stalag- mitic floor. In this state, on entering the lower cave, the walls would be found perforated by marine animals, and no traces of animal life or of human art would present itself ; but on excavating the floor, both would be found below the stalagmite ; whilst if the curious inquirer should drive his pick into the roof, its fragments would bear testimony to the same fact. 64 Fig. () represents the final state of the cavern. Fig. 6. That caverns are occasionally filled with water, and after remaining full perhaps for centuries, are drained by artificial or natural causes, is well known. A very interesting case presented itself to me when visiting the caverns of Mitchelstown in Ireland. These caverns had recently (1833) become accessible, and were then very imperfectly explored. I expressed to the guides my wish to visit some of the unexplored portion, and, after traversing various chambers during six hours, we entered a long and lofty cavern, the floor of which sloped rather steeply towards one side. The whole floor was covered with a coat of soft red mud, about three inches thick, still holding a portion of the water in which it had been sus- pended. No trace whatever of the footsteps of man or of animals appeared ; the impression of our own feet alone marked the track up to the point which we had reached. Being rather in advance of my companions, my attention was suddenly attracted by what ap- peared to me to be about a bushel of soot lying in a small heap on the floor. On examination, I found it to consist of a moist spongy substance, of a black colour, which might, if dry, have assumed the form of a coarse black powder. Asking the opinion of my guide, he suggested that it might have been the remains of a fire lighted by some previous explorer ; but this was inadmissible. I looked round for matter of the same kind, but on further search I could not detect any other instance ; however, accidentally casting my eye 65 towards the roof of the cavern, I observed a black patch vertically above the heap of supposed soot lying on the floor, and from 20 to 30 feet above it. The dotted line, a b, fig. 5, may repre- sent the position. On my return from the cavern I examined* the black sooty matter* and found that it left but very small traces under the action of the blowpipe. On the following day, having made inquiries as to the drainage of the neighbouring country, I was informed that about twenty years before my visit, a stream of water had been diverted from the valley in which it originally flowed, into another adjacent valley. I then visited several quarries, in one of which, about a mile from the caves, I observed a small stream of water terminating in a little pool or sink. In this pool I noticed slight eddies, which occasionally sucked in very small particles floating on the surface of the water. I now visited the valley from which the original stream had been diverted, and found at some elevation a peat bog to which it had pro- bably given rise. This peat was in several parts nearly black ; the most decayed portion greatly resembled the black matter I had brought from the cavern. The origin of this black matter in the cavern now became apparent. The large caverns I had visited were considerably below the level of the peat moss, and the stream which flowed through it. A portion of its waters was conveyed by sinks and crevices into the caves, and kept them continually full. There must, however, have been some very small leakage through which, when the stream which supplied the water was cut off, those caverns were, after many years, laid dry. A small mass of unconsolidated peat, sufficiently light to float, must have been conveyed by the water into those caverns. When it arrived at the spot on which the black matter was found, the piece of peat which still floated must have been pressed against the roof of the cavern. Remaining there undisturbed for years, it may have become by decomposition specifically heavier than water, and then have subsided vertically down on the floor to the place on which I found it, leaving in the black spot on the roof the certificate of its former residence. On the other hand, the piece of peat may have retained its power of floating, and only have descended to the floor of the cavern by the slow escape of the water. VOL. x. F 66 Such circumstances as these ought to induce us to examine with great caution, any instances of the occurrence of works of human art mixed with the remains of animals not yet proved to have been co- existent with man. Accident might have conveyed and hidden in the Mitchelstown caverns, £ portion of human dress instead of a patch of peat. It is obvious that under slightly altered circumstances, in- struments formed by man, the bony remains of his frame, or those of other recent animals, might, by still existing causes, be conveyed into deep recesses in the bowels of the earth, and there deposited with the remains of animals of an entirely different geological age. Cases might occur in which the water passing in larger quantity would convey into such caverns a quantity of suspended mud, differing in its character at various seasons, and thus silt up the confused relics of distant ages in a regularly stratified deposit. It is quite possible that the human remains might thus be enclosed beneath the stalagmitic crust, whilst the more ancient remains were scattered above it, uncovered, or covered by another coat of stalagmite. If we suppose the existence of two upper caves, B and C, at dif- ferent heights, each separately communicating with the lowest cave, A, as in fig. 7, then still more remarkable facts might ultimately present themselves to those whom accident should lead to examine the lowest cave. If, for example, the highest of these caves (C) contained only the remains of the extinct races of animals, and the other, or middle cave (B), nothing but those of man and the works of his own hands, the following series of events might occur : — 1st. A flood directing its course wholly through the middle cave (B), might wash down the fragments of the bones and works of man from that cave, and deposit them on the floor of the lowest cavern (A). 2nd. In a long series of years, a thick stalagmitic covering might be formed, giving an entire new stony floor to that cavern. 3rd. Afterwards another flood, rising to a higher level, acci- dentally taking its course through the highest cave (C), might cover this new stalagmitic floor of the lowest cave (A) with the bony frag- ments of these more ancient animals. 4th. The continued infiltration from above might again cover 67 these remains with another thick coating of stalagmite ; such altera- tions might even be several times repeated. The annexed sketch will explain this case more clearly : — Fig. 7. The great geological law, that the order of succession of strata in- dicates the order of their antiquity, the lowest being always the oldest, is limited by the condition that those strata shall not have been removed from their original beds. But the action of causes still existing may have produced apparent deviations from this order, and the present state of geological science seems to require an examination of such exceptional cases. If a great river, similar to the Mississippi or the Amazon, flowed through a country whose superficial stratum consisted of a thin bed of chalk succeeded by gault, then during thousands of ages it would distribute, by means of an ocean current, its milky burden over the bottom of the existing ocean, on which, after a lengthened interval, a bed of chalk would reappear. When the superficial bed of chalk over which the river flowed was cut through, its waters would begin to act on the newly-exposed gault ; and after another period of equally vast length, a stratum of gault might cover the chalk, thus producing an extensive inversion of the two strata. But this would be dependent on the relative fineness and specific gravity of the particles of the two substances. It is possible that the particles of gault, if larger or of greater specific gravity than those of the chalk, might arrive at a greater terminal velocity, and 68 even overtake and pass through those of the chalk still suspended, thus forming a bed below the chalk, or a mixed bed of chalk passing into gault, and then ultimately a bed of gault above the chalk. In such circumstances few or none of the larger fossils would occur, but possibly the remains of infusorial animals might enable us to identify the material of the ancient and of the new but inverted deposit of gault. The case of remains of human art found imbedded with bones of extinct races of animals in deposits of ancient gravel, seems to require a different explanation. Admitting, however, the existence of those animals to have been contemporaneous with the original distribution of the gravel, it by no means certainly follows that the race of man was coeval with them. For the remains of man and his rude arts might occur on the surface of that gravel long ages after the extinction of those races of animals. Several causes might produce their mixture : — 1st. A vast lake bursting its barriers by erosion, or by an earth- quake, might carry before it in its impetuous course the superficial remains of man, mixed up with vast quantities of gravel, containing the bones of the extinct races of animals, and deposit them over a large area of land at a lower level. 2nd. The change of the course of a river, or of a branch of its delta, might produce the same mixture of the remains of two distinct and far distant ages. It might, by the clearing out of its new channel, carry off the gravel and the remains of extinct animals, and deposit them, mixed up with specimens of human art, on spots which, after a few centuries, might again reappear as dry land. 3rd. A narrow pass, the outlet of a stream of water, might be stopped up by the avalanches falling from a glacier after a severe winter, and the lake formed by the stream might thus periodically rise, until the pressure broke through the barrier. 4th. Amongst the phenomena occurring during earthquakes, it has been observed that large cracks have suddenly opened and as suddenly closed, either immediately or shortly after. During these momentary or temporary openings, the remains of the arts of man, and even man himself, may have dropped into the chasm. Under such circumstances, remains of man and his arts might occur in 69 formations of any date. If the cleft occurred in rock or in any very hard material, traces of it would remain to indicate their origin . If it occurred in clay or softer material, the track through which these remains entered might he partially or even entirely obliterated. If the cleft occurred in tolerably compact gravel and then imme- diately closed, it would scarcely be possible at a future period to trace its origin. The discussion of the recent observations of Mr. Prestwich on flints, worked apparently by the hand of man, found deeply im- bedded in ancient gravel, as well as the extensive observations of Dr. Falconer on the bone-caves of Sicily, have given a new and important interest to the great question of the antiquity of the resi- dence of our race on the planet we inhabit. Having examined a few of these flint-instruments, I am satisfied that several of them have been worked by human hands. This opinion is founded upon the previous examination many years ago of the mode then used for making gun-flints. Amongst the many valuable observations of Dr. Falconer, one fact to which he testifies deserves the most marked attention, and may possibly assist in directing us to the true solution of the problem. Dr. Falconer has noticed the fact that the greater portion of these bones belong to the Hippopotamus, and also that they occur in their several deposits in enormous numbers. In each cave there must have been several thousands, if not tens of thousands, of individuals. The question immediately suggests itself, what causes produced this vast collection of individuals of the same race entombed in one common sepulchre ? It is scarcely possible to suppose that any instinct could have led the Hippopotamus, when death approached, to have chosen particular spots where the bones of his race were exposed to his view. If this were so, then most probably the existing race would possess the same instinct. Another question arises : Were these remains originally deposited in different localities, and afterwards transported by some common cause to these various caverns and beaches ? Water seems the only probable mode of conveyance : if this were so, traces of the rolling action of water must be found on all the bones, but this I apprehend is not 70 the case. Moreover, it is difficult to conceive how water could have collected the bones of a multitude of individuals of the same race, distributed over a wide extent of country, into a few favoured localities. The bones of all other animals inhabiting the same country, and remaining on its surface, would have been exposed to the same action, and should have been deposited in the same tomb. If these animals all perished at the same time in each locality, some common cause must have produced the catastrophe. Although the existing evidence may be insufficient to lead us to the true solution of this interesting question, yet it may be useful to throw out hypotheses, which, by accounting for some of the facts, shall direct the attention of future observers to the examination of such special points as may either partially support or directly dis- prove these conjectures. With this view I shall offer two conjectures, one dependent on the subsidence of the land, the other upon the rising of the waters. Conjecture I. — By the subsidence of the land. Let us imagine that the basin of the bottom of the Mediterranean had at a former period been on a level with, or just above the African continent. Sicily and the various islands would then have stood above it as mountain chains. One portion of the drainage of this land may have been effected by a vast river passing into the Atlantic through the opening now known as the Straits of Gibraltar. In this state of things extensive freshwater lakes arid other large rivers may have contributed to support large herds of Hippo- potami. In such circumstances the gradual subsidence of this land would check the outflow of its rivers, and occasion extensive marshes and lakes, a state of things favourable to the increase of the Hippo- potami. As the subsidence proceeded, those animals which dwelt on the banks of the lakes and rivers would be driven inland. The waters of the Atlantic, entering through the channel of the former river, would convert the low ground and the marshes into sea, and thus gradually isolate the sinking land from the African coast. When this state of the country had caused the Hippopotami to multiply rapidly, an increased rapidity in the sinking of its lands through the waters, might drive those animals rapidly to the higher 71 lands, which would then form islands, on the borders of which they would congregate in multitudes, until numbers of them, collected in ravines, rushing on in their attempts to escape in search of food, might trample each other to death and leave their bodies at the foot of impassable precipices washed by this new sea. Conjecture II. — Let us suppose that the basin of the Mediter- ranean was formerly dry land shut in from the Atlantic by a barrier at the Straits of Gibraltar. In these circumstances the whole of the present Mediterranean Sea would have been a country sunk more or less under the level of the ocean ; just as a large tract of country around the Dead Sea is at present. The country included in this great depression might be warmer than others situated in the same latitude, and would be full of lakes fed by rivers, since there could be no drainage except from evaporation. It would therefore probably be favourable to the growth of the Hippopotamus. Imagine now some convulsion to have opened the Straits of Gibraltar, so as to have allowed the waters of the Atlantic to enter this vast basin. The salt river thus introduced might require days, or weeks, or months, or years, before it filled this immense cavity ; it might also increase its velocity as it wore away the channel of its entrance. Under these circumstances the Hippopotami would be gradually driven to the higher ground, and those mountainous regions which now form the islands of the Mediterranean would then have re- ceived on their shores the hosts of animals, driven by this inundation to seek dry land on which to repose and food on which they might subsist. Both of these hypotheses account for the aggregation in different localities, of the remains of large numbers of animals of the same class, dwelling amongst rivers and lakes ; both equally account for their destruction on the same spots, either by trampling each other to death in the rush to escape, or by the slower processes of drown- ing or starvation. But neither hypothesis accounts for the fractured state of these bones, even though the animals should have rushed over the precipice. It might be expected that some portion of these Hippopotami, escaping from the deluge which destroyed their race, would have reached the plains of some larger island, and then 72 separating in search of food, have left their carcases, wasted hy famine, variously scattered at a distance from each other. The following questions are thus suggested for inquiry : — Are the bones of young and of old animals mixed indiscriminately throughout the whole of these bone-beds ? Is it possible to distinguish the bones of females from those of males ? Do the bones of the larger and stronger individuals occur in greater abundance near the top of the bone-beds, and those of the smaller and feebler animals nearer the bottom of those beds ? If the sea followed these animals quickly, the young and the feeblest would perish before they reached the great deposits of bones, Although not at all confident that either of these explanations is the true one, I look upon them as open to less objection than any other of which I have yet heard, and therefore give them a tem- porary assent. The conclusion to which these remarks lead, is that whilst we ought to be quite prepared to examine any evidence which tends to prove the great antiquity of our race, yet that if the facts adduced can be explained and accounted for by the operation of a few simple and natural causes, it is unphilosophical to infer the coexistence of man with those races of extinct animals. The interest and importance of the subject are such, that new and still more extensive researches cannot fail to be made ; and if these remarks shall in any way contribute to lighten the labour of future inquirers, or to promote the true explanation of the facts, they will have fully attained the object of their publication. XL "Remarks on Colour-Blindness/' By Sir JOHN F. W. HERSCHEL, Bart., F.R.S. [Extracted from a Report by Sir J. F. W. H. on Mr. Pole's paper on the same subject*, and communicated at the request of Jhe Pre- sident and Council.] I consider this paper as in many respects an exceedingly valuable contribution to our knowledge of the curious subject of colour-blind- * " Proceedings," vol. viii. p. 172 ; and vol. ix. p. 716. 73 ness — 1st, because it is the only clear and consecutive account of that affection which has yet been given by a party affected, in pos- session of a knowledge of what has yet been said and written on it by others, and of the theories advanced to account for it, and who, from general education and habits of mind, is in a position to discuss his own case scientifically ; and 2ndly, for the reasons the author himself alleges why such a person is really more favourably situated for describing the phenomena of colour-blindness, than any normal- eyed person can possibly be. It is obvious that on the very same principle that the latter considers himself entitled to refer all his per- ceptions of colour to three primary or elementary sensations — • whether these three be red, blue, and yellow, as Mayer (followed in this respect by the generality of those who have written on colours) has done, or red, green, and violet, as suggested by Dr. Young, reasoning onWollaston's account of the appearance of the spectrum to his eyes — on the very same principle is a person in Mr. Pole's condition, or one of any other description of abnormal colour- vision, quite equally entitled to be heard, when he declares that he refers his sensations of colour to two primary elements, whose combination in various proportions he recognizes, or thinks he recognizes, in all hues presented to him, and which, if he pleases to call yellow and blue, no one can gainsay him ; though, whether these terms express to him the same sensations they suggest to us, or whether his sensation of light with absence of colour corresponds to our white, is a question which must for ever remain open (although I think it probable that such is really the case). All we are entitled to require on receiving such testimony is, that the party giving it should have undergone that sort of education of the sight and judgment, especially with reference to the prismatic decomposition of natural and artificial colours, for want of which the generality of persons whose vision is unimpeachably normal, appear to entertain very confused notions, and are quite incapable of discussing the subject of colour in a manner satisfactory to the photologist. It is as necessary to distinguish between our sensations of colour, and the qualities of the light producing them, as it is to distinguish between bitterness, sweetness, sourness, saltness, &c., and the che- mical constitution of the several bodies which we call bitter, sweet, &c. Whatever their views of prismatic analysis or composition 74 might suggest to Wollaston and Young, I cannot persuade myself that either of them recognized the sensation of greenness as a con- stituent of the sensations they received in viewing chrome yellow, or the petal of a Marigold on the one hand, and ultramarine, or the blue Salvia on the other ; or that they could fail to recognize a certain redness in the colour of the violet, which Newton appears to have had in view when he regarded the spectrum as a sort of octave of colour, tracing in the repetition of redness in the extreme refrangible ray, the commencement of a higher octave too feeble to affect the sight in its superior tones. Speaking of my own sensations, I should say that in fresh grass, or the laurel- leaf, I do not recognize the sensation either of blue or of yellow, but something sui generis ; while, on the other hand, I never fail to be sensible of the presence of the red element in either violet, or any of the hues to which the name of purple is indiscriminately given ; and my impression in this respect is borne out by the similar testimony of persons, good judges of colour, whom I have questioned on the subject. I would wish, then, to be understood as bearing in mind this distinction when speaking of the composition of colours by the super- position of coloured lights on the retina. It seems impossible to reason on the joint or compound sensation which ought to result from the supraposition in the sensorium of any two or more sensa- tions which we may please to call primary ; so that if, following common usage, I speak in what follows of red, yellow, and blue (or in reference to Young's theory of red, green, and violet) as primary colours, I refer only to the possibility of producing all coloured sensa- tions by the union on the retina of different proportions of lights, competent separately to produce those colours, which is purely a matter of experience. It is necessary to premise this, when I remark that I by no means regard as a logical sequence Mr. Pole's conclusion in § 15, that because he perceives as colours only yellow and blue, therefore the neutral impression resulting from their union must be that sensation which the normal-eyed call green. On the contrary, I am strongly disposed to believe that he sees white as we do, for reasons which I am about to adduce. Mr. Maxwell has lately announced his inability to form green by the combination of blue and yellow. On the other hand, the pris- 75 matic analysis of the fullest and most vivid yellows (those which excite the sensation of yellowness in the greatest perfection), as the colours of bright yellow flowers, or that of the yellow chromate of mercury, clearly demonstrates the fullness, richness, and brilliancy of their colour to arise from their reflexion of the whole, or nearly the whole of the red, orange, yellow, and green rays, and the sup- pression of all, or nearly all the blue, indigo, and violet portion of the spectrum. On the hypothesis of an analysis of sensation correspond- ing to an analysis of coloured light, these facts would seem incom- patible with the simplicity of the sensation yellow, and it would appear impossible (on that hypothesis) to express them otherwise than by declaring red and green to be primary sensations, and yellow a mixture of them — a proposition which needs only to be understood to be repudiated — quite as decidedly as that the sensation of green- ness is a mixture of the sensations of blueness and yellowness, and for the same reason ; the complete want of suggestion of the so-called simple sensations by the asserted complex ones. Mr. Maxwell's assertion that blue and yellow do not make green, assuredly appears startling as contradictory to all common experience ; but the common experience appealed to is that of artists, dyers, and others in the habit of mixing natural colours as they are presented to us in pigments, coloured tissues, &c., who have for the most part never seen a prismatic spectrum, or at least attended to its phseno- rnena. The perceptions of colour afforded by such objects are those of white light from which certain rays have been abstracted by ab- sorption, that is to say, they are negative hues, or hues of darkness rather than of light, inasmuch as all the colouring of the artist is based, not on the generation, but on the destruction of light. This circumstance, which is not generally recognized, even among edu- cated artists, has vitiated all the language of chromatics as applied to art, and so placed a barrier between the painter and the photologist, which has to be surmounted before they can come to a right under- standing of each other's meaning. It is evident, that, to make experiments on the subject free from this objection, absorptive colours must be discarded, at least in bodily mixture with each other. Thus it is true that a dingy green may be produced by rubbing together in powder prussian blue and the yellow chromate of mer- cury above mentioned ; but both these agree in reflecting a con- 76 siderable, and the latter a very large proportion of green light, to the predominance of which in the joint reflected beam its tint is owing. So also, when blue and yellow liquids (not acting chemically on each other) are mixed, as in water-colour drawings, greens, sometimes very lively ones, are produced. In these cases the yellow absorbs almost all the whole of the incident blue, indigo, and violet light, and the blue a very large proportion of the red, orange, and yellow, both allowing much green to pass ; and to this, rather than to a mixture of the other rays, the resulting tint is due. In the light transmitted by cuprate of ammonia of a certain thick- ness, the red, orange, yellow, and green are wholly extinguished, while the blue, indigo, and violet are allowed to pass . The result is the fullest and bluest blue it is possible to obtain. From this result, compared with that derived from the analysis of natural yellows, it follows that the union on the retina of the yellowest yellow, and the bluest blue, in such proportions that neither shall be in excess, so as to' tinge the resulting light either yellower blue, is not green, but white. The same conclusion follows from dividing the spectrum into two, the one portion containing all the less refrangible rays up to the limit of the green and blue, the other all the remaining rays. If the blue portion be suppressed, and the remainder reunited by a refraction in the opposite direction, the resulting beam is yellow, if the other, blue, both vivid colours — but if neither, white of course, and not green, results from the exact recomposition of the original white beam. It may be objected to this, that in the complementary colours exhibited by doubly-refracted pencils in polarized light, yellow is often found to be complementary to purple, and blue to orange. But in neither of these pairs of colours is the spectrum divided in the manner above indicated ; and, moreover, in many instances yellow and blue are found as complementary colours in the oppositely polarized pencils ; of which examples will be found in the scale of tints produced by sulphate of barytes in my paper " On the Action of Crystallized Bodies in Homogeneous Light" (Phil. Trans. 1820, Table I.). " Rich yellow" appears also as opposed to "full blue" in the scale of complementary tints exhibited by mica in my " Trea- tise on Light" (Encyc. Metrop., art. 507). It is not asserted that either a good yellow or a good blue cannot be produced otherwise 77 than in a particular manner, but that they can be produced in that particular manner, and that when so produced, their union affects the eye with no sensation of greenness. Let two very narrow strips of white paper, A, B, be placed parallel to one another in sunshine, so as to be seen projected on a perfectly black ground (a hollow shadow), and viewed through a prism having the refracting edge parallel to them, the refraction being towards the eye, and let the nearer B be gradually removed towards A, so that the red portions of B's spectrum shall fall upon the green portion of A's. Their union will produce yellow, or, if too far advanced, orange. On the other hand, it will be seen that the yellow space in B's spectrum on which the blue of A's falls is replaced by a streak of white, — whiteness, and not greenness, being the resultant of the joint action of these rays on the retina. If the strips be made wedge-shaped, tapering to fine points, and A being still white, B be made of paper coloured with the yellow chromate of mercury before mentioned, the whiteness of the streak where the blue of A mixes with the yellow of B near the pointed extremities will be very striking. f There is a certain shade of cobalt-blue glass which insulates, or very nearly so, a definite yellow ray from the rest of the spectrum, suppressing the orange and a great deal of the green. If the spec- trum of B, formed and coloured as last described, be viewed through this glass, a very well-defined image of it, clearly separated from its strong red and very faint blue images, will be seen. As the glass in question allows blue rays to pass, the white object, A, besides its definite yellow image, will form a broad blue, indigo, and violet train nearer to the eye. Now let B be gradually brought up towards A, so that the violet, indigo, and blue rays of this train shall coincide in succession with the yellow image of B, — no sensation of greenness will arise at any part of its movement. Again, if a white card be laid down on a black surface, the edge nearest the eye, when refracted towards the spectator by a prism, will of course be fringed with the more refrangible half of the spectrum. Let this be viewed through such a glass, and in the blue space so seen introduce one half of a narrow rectangular slip of paper thus coloured, having its upper edge in contact with the lower edge of the white card, the other half pro- jecting laterally beyond the card. In this arrangement the definite 78 image of the yellow paper insulated by the glass will be seen divided into a yellow half, projecting beyond the blue fringe, and a purplish- or bluish-white one within it, hardly to be distinguished from the image of the white paper, of which it seems a continuation, and which through the glass in question appears a pale blue. This same purplish tint was observed to arise also under the following circum- stances : — Laying down in a good diffused light a paper of an ex- ceedingly beautiful ultramarine blue, and beside it, and somewhat overlapping it, another coloured with the same yellow chromate, I set upon the line of junction a sheet of glass inclined to the plane of the papers upwards towards the eye, so as to allow the blue to be seen by transmitted light, while the yellow reflected from the glass was at the same time received into the eye. By varying the inclina- tion of the glass, the yellow reflexion could be made more or less vivid, so as either to be nearly imperceptible or quite to kill the blue of the paper. But at no stage of its intensity, gradually in- creased from one to the other extreme, was the slightest tendency to greenness produced. The colour passed from blue to yellow, not through green, but through a pale uncertain purplish tint, not easy to describe, but as remote from green as could be well imagined. Of course in all such experiments one eye only must be used. Stereoscopic superposition of colour, which at first sight would ap- pear readily available, does not satisfy the requisite conditions, and yields no definite results. The conclusions from these facts may be summed up as follows : — 1st. That in no case can the sensation of green be produced by the joint action on the eye of two lights, in neither of which, separately, prismatic green exists ; 2ndly. That the joint action of two lights, separately producing the most lively sensations of blue and yellow, does not give rise to that of green, even when one of them contains in its composition the totality of green light in the spectrum ; and, 3rdly. That all our liveliest sensations of yellow are produced by the joint action of rays, of which those separately exciting the ideas of red and green form a large majority ; and that a decided yellow impression is produced by the union of these only. From these premises it would seem the easiest possible step to conclude the non-existence of yellow as a primary colour. But this conclusion I am unable to admit in the face of the facts, — 1st, that 79 a yellow ray, incapable of prismatic analysis into green and red, may be shown to exist, both in the spectrum and in flames in which soda is present ; and 2ndly, that neither red nor green, as sensations, are in the remotest degree suggested by that yellow in its action on the eye. Whether under these circumstances the vision of normal- eyed persons should be termed trichromic or tetrachromic, seems an open question. That Mr. Pole's vision is eftchromic, however, there can be no doubt. If I could ever have entertained any as to the correctness of the views I have embodied of the subject in that epithet, after reading all I have been able to meet with respecting it, this paper would have dispelled it. That he sees blue as we do, there is no ground for doubting ; and I think it extremely likely that his sensa- tion of whiteness is the same as ours. Whether his sensation of yellow corresponds to ours of yellow, or of green, it is impossible to decide, though the former seems to me most likely. One of the most remarkable of the features of this case, and in- deed of all similar ones, is the feebleness of the efficacy of the red rays of the spectrum in point of illuminating power, which certainly very strongly suggests an explanation drawn from the theory of three primary coloured species of light, to one of which the colour-blind may be supposed absolutely insensible. Mr. Pole himself evidently leans to this opinion. I had satisfied myself, however, in the case of the late Mr. Troughton, that the extreme red — that pure and de- finite red which is seen in the solar spectrum only when the more luminous red is suppressed, and in which I cannot persuade myself that any yellow exists, was not invisible to him, — though of course not seen as red ; and on supplying Mr. Pole with a specimen of a glass, so compounded of a cobalt-blue and a red glass as to transmit posi- tively no vestige of any other ray, but that copiously, so that a candle seen through it appears considerably luminous, and the window-bars against a cloudy sky are well seen if other light be kept from falling on the eye, — I am informed by him that he saw through it " gas, fire and other strong lights with perfect distinctness," and that the colour so seen is a " very deep dark yellow." Now it seems to me impossible to attribute this to any minute per-centage of yellow light of the same refrangibility, which this can be supposed to con- tain. The purity of its tint is extraordinary ; and its total intensity 80 so small, that supposing it reduced to one- tenth of its illuminating power by the suppression of the whole of its primary red constituent, I cannot imagine that any gas-flame or fire-light would be visible through it, or any other luminous body but the sun. Still it remains a fact, however explained, that the red rays of the spectrum generally are to the colour-blind comparatively but feebly luminous. Mr. Pole speaks of red in more places than one as "a darkening power ;" and in the letter I have received from him in reply to my query as to the visibility of light through the red glass above mentioned, he insists strongly on its action as darkness. This, however, can only be understood of the effects of red powders in mixture, and not of red light ; and as, to our eyes, an intense blue powder, such as prussian blue, has, besides its colorific effect, a vio- lent darkening one (owing to its feeble luminosity), so, to the colour- blind, red powders, when added to others, contribute but little light in proportion to the bulk they occupy in the mixture, and therefore exercise a darkening power by displacing others more luminous than themselves. I think it therefore very probable that red appears to the colour-blind as yellow-black does to the normal-eyed, or, in other words, that our higher reds are seen by them as we see that shade of brown which verges to yellow — that of the faded leaf of the tulip-tree for instance. Now it is worthy of remark, that it is very difficult for the normal-eyed to become satisfied that the browns are merely shades of orange and yellow. Brownness (such at least has always been my own impression) is almost as much a distinct sensation as greenness ; so that I am not at all surprised at the expression in § 22, that the " sensation of red as a dark yellow is certainly very distinct from full yellow," or that a colour-blind person should, after long and careful investigation, arrive at the conclusion that red is not to him a distinct colour. I find all this completely applicable to my own perception of the colour brown. Mr. Pole (§ 11) appears to lay great stress on the fact, that in a closed colour circle in which red, yellow, and blue are so arranged that each shall graduate into both the others, there occurs in the space where red and blue graduate into each other, " a hue of red which is to him absolutely insensible," and that this red corresponds not to that colour which, under the name of carmine, offers to the normal-eyed the beau-ideal of redness, but what they term " crim- 81 son.'* Invisibility, as an element of colour, must not here be con- founded with invisibility as light. It is certain that he sees the crimson. It is not to him black, but (just what it ought to be on the supposition that his vision is dichromic, and the union of his colours produces white) a neutral, obscure grey ; grey being only an abbreviated expression for feeble illumination by white light. In a circle coloured with three elements graduating into each other, there is no neutral point — none, that is, where whiteness or greyness can exist ; but when coloured with only two elements, such as yellow and blue (positive yellow and blue, that is, whose union produces white, not green), there are of necessity two neutral points which would be both equally white, i. e. equally luminous, if the two ex- tremities of each of the coloured arcs graduated off by similar de- grees. But this not being the case with the yellow arc, one of its ends to the colour-blind corresponding to a continuation of the red, and so being deficient in illuminating power, the point of neutrality will be that where a feebler yellow is balanced by a feebler blue, and will therefore be less luminous, i. e. less white or more grey than the other neutral spot. It is evident, from the general tenor of Mr. Pole's expressions throughout this paper, that his ideas on the subject of colour are gathered mainly from the study of pigments and absorptive (i. e. negative) colours, and not from that of prismatic (or positive) ones. In other words, his language is that of the painter, as distinguished from the photologist ; the distinction con- sisting in this — that in the former colour is considered in its con- trast with whiteness, in the other with blackness ; and thus it is that black is considered by many painters as an element of colour, as whiteness necessarily is by photologists. I may perhaps be allowed to add a few words as to the statistics of this subject. Dr. Wilson gives it as the result of his inquiries, that one person in every eighteen is colour-blind in some marked degree, and that one in fifty-five confounds red with green. Were the average anything like this, it seems inconceivable that the exist- ence of the phenomenon of colour-blindness, or dichromy, should not be one of vulgar notoriety, or that it should strike almost all uneducated persons, when told of it, as something approaching to absurdity. Nor can I think that in military operations (as, for in- stance, in the placing of men as sentinels at outposts), the existence, VOL. x. G 82 on an average, of one soldier in every fifty-five unable to distinguish a scarlet coat from green grass would not issue in grave inconve- nience, and ere this have forced itself into prominence by pro- ducing mischief. Among the circle of my own personal acquaint- ance I have only known two (though, of course, I have heard of and been placed in correspondence with several) ; and a neighbour of mine, who takes great delight in horticulture, and has a superb collection of exotic flowers, informs me that among the multitude of persons who have seen and admired it, he does not recollect having ever met with one who appeared incapable of appretiating the variety and richness of the tints, or insensible to the brilliancy of the nume- rous shades of red and scarlet. It may be, however, that the per- centage is on the increase — certainly we hear of more cases than formerly ; but this probably arises from the fact of this, like many other subjects, being made more generally matter of conversation. In further reference to the question of the superposition of colours in the spectrum, or of the intrinsic compositeness of rays of definite refrangibilities, I may mention a phenomenon which I have been led to notice in the prosecution of some experiments on the photo- graphic impressions of the spectrum on papers variously prepared, which appeared to me, when first noticed, quite incompatible with the simplicity of those rays at least which occupy the more luminous portion of the spectrum, extending between the lines marked D and E by Fraunhofer, and clearly to demonstrate the presence of green light over nearly the whole of that interval. In these experiments the spectrum formed by two Fraunhofer flint prisms, arranged so as to increase the dispersion, and adjusted to the position of least de- viation for the yellow rays, was concentrated by an achromatic lens, and received on the paper placed in its focus, which could be viewed from behind. A series of white papers impregnated with washes of various colourless or very slightly coloured chemical preparations, and dried, were exposed ; and the spectrum being received on them, and the centre of the extreme red image as viewed through a stand- ard glass, adjusted to a fiducial pinhole ; a sensitizing wash of nitrate of silver, or any other fitting preparation, was copiously applied to the exposed surface while under the action of the light. Now, under these circumstances, I uniformly found that whereas the spectrum viewed from behind through the paper exhibited all over the space 83 in question a dazzling very pale straw-yellow, hardly distinguishable from white, yet as the photographic action proceeded, and the translucency of the paper began to be somewhat diminished also by incipient drying, very nearly the whole of that space became occu- pied by a full and undeniable green colour, so as to give the idea of a distinctly four-coloured spectrum — red, green, blue, and violet; the yellow being in some instances almost undiscernible, and in others limited to a mere narrow transitional interval rather orange than yellow. It was at the same time evident that a great extinction of light (illumination independent of colour) had also been operated, the vivid glare of the part of the spectrum in question being reduced to a degree of illumination considerably inferior to the red part, or, at all events, not much superior. The change of colour was far greater than could be attributed to any effect of contrast, and was proved decisively not to be due to that cause by hiding the adjacent red and blue when the green remained unaffected in apparent tint. When, for the photographic preparations wetted as described, ordinary, dry, coloured papers were substituted, the change of colour in question was always produced whenever the thickness of the paper and its absorptive power were not such as to destroy or very much enfeeble the more refrangible light. Taking, as a term of compa- rison, a purely white, wove, writing-paper, I found that the substi- tution of writing-paper, tinted with the ordinary cobalt blue com- monly met with, sufficed to give a very great extension of the green, almost to the extinction of the yellow, while, when the papers used were pale-yellow or clay-coloured, answering to the tints called "buff" or "maize" (nearly approximating to Chevreul's orange 4 and 3), and which might naturally have been expected to transmit yellow rays more abundantly at all events than the blue, the spectra (viewed at the back of the papers) were particularly full and abun- dant in green, occupying the whole of the debateable ground. In the case of the former, a narrow yellow space was seen, and the blue was very much enfeebled, and separated from the green by a very perceptible suddenness of transition. With the latter the green was finely exhibited, and the yellow confined to a narrow orange-yellow border : the blue and violet much enfeebled. On further considering these facts, there seemed to be but three ways of accounting for them : — 1st, by the effect of contrast. This 84 I consider to be disposed of by the suppression of the adjacent colours, as recorded above. 2ndly, by extinction of a yellow element of colour over the space DE, allowing a substratum of green to sur- vive ; or, which comes to the same, by the extinction of the red ele- ment over the same space, which, by its combination with (an as- sumed elementary) green, produced the original brilliant straw-yellow. And 3rdly, by admitting as a principle, that our judgment of colours absolutely, in se, and independent of contrast, is influenced by the intensity of the light by which they affect the eye, and that very vivid illumination enfeebles or even destroys the perception of colour. As the apparent change of colour from pale-yellow to green in the cases above related was always accompanied with a great diminution of general intensity, it occurred to me to produce such diminution by optical means, which should operate equally on all the coloured rays, and diminish all their intensities in the same ratio. This was accomplished by viewing the spectrum (as projected on purely white paper) by reflexion on black glass, or by two successive reflexions in different planes, and I found the very same effect to take place. That portion DE of the spectrum which in the unre- flected state appeared dazzlingly bright and nearly colourless, was seen by one such reflexion, and still more so by two, green. The extension of the green region was greater, and the limitation of the yellow portion more complete, according to the amount of illumina- tion destroyed by varying the angles of incidence on the glasses. When much enfeebled by two cross reflexions, the aspect of the spectrum was that represented in Chevreul's coloured picture of it from the line A to H. When enfeebled by other means, as by view- ing the spectrum thrown on a blackened surface, the effect was exactly the same. The last of our three alternatives, then, would appear to be esta- blished as the true explanation ; and in respect of the second, it is eliminated by the consideration that neither the slight degree of coloration in the bluish papers, or the tint of the pale-yellow ones which effected the change, would give rise to so great a preferential extinction of yellow or red rays as an explanation founded on that alternative would require. The phenomenon is certainly a very striking one, and has created great surprise in those to whom I have shown it. XII. " On the Laws of Operation, and the System atization of Mathematics/' By ALEXANDER J. ELLIS, Esq., B.A., F.C.P.S. Communicated by ARCHIBALD SMITH, Esq., M.A. Received May 26, 1859. (Abstract.) The object of the following investigation is to give a firmer basis to the calculus of operations, to assign the strict limits and con- nexion of the mathematical sciences, and to found them upon purely inductive considerations, without any metaphysical or a priori reasoning. Starting with the indemonstrable but verifiable hypothesis, that objects exist external to the subject, we recognize equality as exist- ing between objects with common and peculiar properties, in respect of their common properties. Operations, which, when performed on equal objects, produce equal objects as their result, are recognized as equal, in respect to the common properties considered in the equali- ties of the objects. When one operation is performed on an object, and another on the resultant object, the single operation by which the first object is transformable into the last is regarded as the product of the other two, the order of succession being important. When the resultant object is the same as the original operand, the product of the operations is termed unity. When two operations performed on the same object produce different resultant objects, the operation of transforming one of these resultant objects into the other, is re- garded as the quotient of the two former'operations. Two opera- tions are termed reciprocal when their product is unity. Hence the quotient of two operations is the product of the one and of the reci- procal of the other. When two objects are combined in any manner so as to produce a third, and the two first are formable from any fourth by two known operations, the single operation by which the third object can be also formed from the fourth, is termed the same combination of the two first operations. From this we gain the con- ception of null or zero, as the operation of annihilating any object in respect to any place. The product of a combination of two opera- tions and a third operation, is the same combination of the products VOL. x. H 86 of each of the combined operations severally and the third operation, in the particular order thus specified, provided all the operations and products are performable on the same operand. The above general conceptions and laws of combined operations hold for any operations whatsoever with their appropriate operand objects ; but the nature of the operations and operands requires especial study. In mathematics, objects are only considered with respect to their three most general properties : first, as contem- platable in discontinuous succession, whence number and Arithmetic ; secondly, as contemplatable in continuous succession, whence ex- tension and Geometry ; and thirdly, as contemplatable in a con- tinuous succession bearing a relation to another continuous succession, whence motion in time and Mechanics. The problem of mathe- matics is, first, to discover the laws of these successions as respects results (that is, statically), by means of considerations drawn from contemplating operations (that is, dynamical) ; secondly, to investi- gate the relations of these laws, giving rise to statical algebra ; thirdly, to reduce all dynamical to statical laws, as in dynamical algebra ; and fourthly, to make the expression of all the results de- pendent on the most simple, viz. those of common arithmetic. The purpose of the problem is to prepare the mind for the further investi- gation of nature, and to increase practical power immediately. In Arithmetic we conceive objects spread out in a scale, and by aggregating those contained between any one and the beginning of the scale, form statical groups, whose distinctive character is derived from the scale. The operation by which any group is formed from .the first object is termed an integer, the especial laws of which are .next investigated. All objects being interchangeable in respect to discontinuous succession, an aggregate is not changed by altering the disposition of its parts. This leads to the first two laws of commu- tation and association in addition. The possibility of arranging objects at once in two horizontal directions, and a third vertical direction, leads to the laws of commutation and association in multi- plication. Combining these with the two former, we have the law of commutative distribution. From the laws of association in multi- plication is immediately deduced the law of repetition or indices. Having obtained these laws, we proceed to study their relations in the algebra of integers, first, statically, in order to reduce all results 87 to the form of a numerical integer ; secondly, dynamically, con- sidering the effect of a variation in the integer employed. This leads to the conception of a formation (Lagrange's "analytical function "), as a combination of a fixed and independently variable integer. Such a combination is, therefore, also itself dependently variable. The inversion of formations, whereby the independent variable is expressed as a formation of the dependent variable, imme- diately engages our attention. The inversion of a sum leads to a difference, with the limitation that the minuend should be greater than the subtrahend. The inversion of a product leads to a quo- tient, with the limitation that the dividend should be a multiple of the divisor. The inversions of a power lead to the root and loga- rithm, with increasing limitations. The study of discontinuous ob- jects then allows the application of these inversions to the solution of problems in common life. The operation by which any group in the arithmetical scale already described is formable from any other group in the same scale, leads to the conception of & fraction, necessarily expressible, according to the general laws of operation, as the quotient of two integers. The operands of such operations must admit of being separated into certain numbers of equal parts, or rather, in order that they may admit of any fractional operation, into any number of equal parts. Thus discontinuous approaches continuous succession. The laws of fractions are the same as the laws of integers, provided the indices used are all integers. The object of the statical algebra of fractions is to reduce all combinations of numerical fractions to numerical fractions. The inversion of formations is less limited than before. There is the same limitation respecting differences, but none respect- ing quotients. The attempt to convert all fractions into radical fractions (whose denominators are some powers of the radix of the system of numeration), leads to the conception of convergent infinite series, and hence allows an approximation to the inversion of a power with a constant index. In Geometry, the notion of continuous succession or extension is derived from the motion of the hand, which recognizes separable but not separated parts. This motion gives the conception of surfaces, which by their intersections two and two, or three and three, give lines and points. Recognizing a line as the simplest form of exten- H 2 88 sion, we distinguish the straight lines, which coincide when rotated about two common points, from the curves, which do not. These straight lines are shown to be fit operands for the integer and fraction operations. By moving one coinciding line over another so as to continue to coincide (by sliding), or to have one point only in com- mon (by rotating), or no points in common (by translation), we obtain the conceptions of angles and parallels, which suffice to show that the exterior angle of a triangle is equal to the two interior and opposite, and that two straight lines meet or not according as the exterior angle they make with a third is not or is equal to, the interior angle. Angles are then considered statically as amounts of rotation not exceeding a semi-revolution. Proceeding to examine the relations of triangles and parallelograms, we discover the opera- tion of taking a fraction of a straight line, and therefore of a triangle and of any rectilineal figure. We see that this operation is, in fact, the same as that of altering a third line into a fourth, so that the multiples of the third and fourth, when arranged in order of magni- tude, should lie in the same order as those of the first and second when similarly arranged. The relation of two magnitudes, with respect to this order, we term their ratio, and the equality of ratios proportion. The inversion and alternation of the four terms of a proportion are now investigated. The operation of changing any magnitude into one which bears a given ratio to it, is called a tensor. The laws of tensors, being investigated, are shown to be the same as those of fractions. They, however, furnish the complete conception of infinite and infinitesimal tensors, by letting one or other of the mag- nitudes by which the ratio is given become infinite or infinitesimal. Thence is developed the law, that tensors differing infinitesimally are equal fop all assignables. Consequently tensors may be represented by convergent series of fractions. The algebra of tensors allows of the inversion of a sum with the same limitation as in the case of fractions, the complete inversion of a product of tensors, and the practical inversion of a power with a constant integral index. This algebra applied to geometry allows of the investigation of all statical relations, that is, of all the geometry of the ancients, in which magnitudes alone were considered, without direction. In respect to areas, the consideration of the parallelogram swept out by one straight line translated so as to keep one point on another straight line, leads to an independent algebra of areas, in which the generating lines are considered immediately. The laws of the relations of lines thus discovered, are shown to be identical with the laws of the relations of tensors. Consequently, with certain limitations, the whole of the algebra of tensors may be interpreted as results in the algebra of areas. This leads to a perfect conception of the principle of homo- nomy, or dissimilar operations having the same laws, and conse- quently the same algebra. In dynamical or modern geometry r, all lines are considered as in construction, having initial and final points. If the initial points of any two straight lines are joined to a third, not on either, and the two parallelograms be completed, the lines drawn from the point parallel to the given lines are dynamically equal to them ; if these last lie on each other, the first two lines have the same direction ; if the last have only one point in common and lie in the same straight line, the first have opposite directions ; and if the last do not lie in the same straight line, the first have different directions, and the angle between the last is the angle between the first lines. Similar defini- tions can be given of direction in the case of angles and circular arcs. If from the final point of any line we draw a line equal to a second, and join the initial point of the first with the final point of the line thus drawn, we are said to append the second to the first, and the joining line is called the appense of the other two. The laws of appension are shown to be the same as those of addition, and are hence expressible by the same signs of combination, the difference in the objects combined preventing any ambiguity. We thus get the conception of a point as an annihilated line. The tensor operation, considered dynamically, leads to the opera- tion of changing a line dynamically so that it should bear the same relation to the result as two given lines bear to each other in magni- tude and direction. This assumes three principal forms according to the difference of direction. If there is no difference of direction, the operation is purely a tensor. If the directions differ by a semi- revolution, the rotation of one line into the position of the other may take place on any plane. The operation is then termed a negative scalar; the tensor, which includes the operation of turning through any number of revolutions, is distinguished as a positive scalar. If the rotation be through any angle, but always on the same plane, 90 the operation is here termed a clinant. If the rotation may take place on any variable plane, the operation is a quaternion. The laws of scalars are immediately proved to be the same as those of tensors, but in addition they introduce the idea of negativity. This enables us in the algebra of scalars, to invert a sum generally, and thus allows of a perfect inversion of the first two formations. But a power with a fixed integral exponent can only be inverted on certain conditions. This partial inversion, however, leads to a solu- tion of quadratic equations, and to a proof that formations consisting of a sum of integral powers, cannot be reduced to null by more scalar values of the variable than are marked by its highest exponent. Hence if such a formation is always equal to null, all the coefficients of the variable must be null. We thus obtain the method of inde- terminate coefficients, by which we are enabled to discover a series which obeys the laws of repetition with respect to its variable, and becomes equal to a power when its variable is an integer. This enables us to define a power with any index, as this series, and hence to attempt the inversion of powers with variable indices, which we succeed in accomplishing under certain conditions. This investigation introduces the logarithm of a tensor, powers with fractional arid negative exponents, and the binomial theorem for these powers. It also induces us to consider the laws offormators, or the operations by which a formation of any variable is constructed. They are shown to be commutative and associative in addition, associative in multiplication, directly distributive and repetitive, but not generally commutative in multiplication, nor even inversely distributive. "When formators are commutative in multiplication and distribution, they are entirely homonomous with scalars, which may even be considered as a species of formators. The results of the former investigation, therefore, show that logarithms, fractional and negative powers, and the binomial theorem hold for these commutative formators. The necessity of tabulating logarithms and of approximating to the solutions of equations, leads to the consideration of a method of deriving consecutive values of formations for known differences of the variable, and of interpolating values of the same formation for intermediate values of the variable ; that is, the algebra of differences. Considering the two operations of altering a formation by increasing the variable, and taking the difference between two different values 91 of the formation (of which operations the first is necessarily unity added to the second), we regard them as formators, and immediately apply the results of that algebra, which furnishes all the necessary formulae. For approximating to the roots of equations, we require to consider the case where the variable changes infinitesimally, thus founding the algebra of differentials, which is, in fact, a mere sim- plification of that of differences, owing to all the results being ulti- mately calculated for assignables only. Finally, to find the alteration in a formation of comnratative*formators, when the variable formator is increased by any other formator, we found the algebra of deri- vatives. In applying the results of scalar algebra to geometry, we start with the fundamental propositions that the appense of the sides of an en- closed figure taken in order is a point, and that when the magnitude and direction of the diagonal of a parallelogram or parallelopipedori, and lines parallel the sides which have the same initial point as the diagonal, are given, the whole figures are completely determined. In order to introduce scalars, a unit-sphere is imagined, with its radii parallel to the lines in any figure, and in known directions. Any line can then be represented as the result of performing a scalar operation on the corresponding radius. The first object is to reduce the consideration of angles to that of straight lines, by the introduction of cosines and sines, which are strictly defined as the scalars represented by the relation of the abscissa to the abscissal radius, and the ordinate to the ordinate radius respectively. These definitions immediately lead to the rela- tions between the cosines and sines of the sums of two angles, and those of the angles themselves, whatever be their magnitude or direc- tion, and thus found goniometry. Defining a projection of any figure on any plane to be that formed by joining the points on that plane corresponding according to any law with those of the figure, we have the fundamental relation that, if the first, and therefore the second figure is enclosed, the appense of the sides of the second in the order indicated by the sides of the first, is a point. The orthogonal projection of any figure, by means of planes drawn perpendicular to any line, being all in one line, each projection can be represented as the result of a scalar operation per- formed on the same unit radius, and hence this projection leads to one invariable relation between scalars. By choosing three lines at right angles to each other on which to project, we obtain three scalar re- lations from every solid figure. If the figure is plane, then by pro- jecting on a line and on a perpendicular to that line, we get two scalar relations. Applying these results to transversals^ where a line parallel to one unit radius cuts several other unit radii, produced either way if neces- sary, we obtain, by considering two intersected radii, the results of trigonometry, and by considering three or four intersected radii, those of anharmonic ratios. As any line drawn from the centre of the unit-sphere may be con- sidered as the appense of three lines drawn along or parallel to three given unit radii, it may be expressed as the sum of the results of three scalar operations performed on these radii respectively. By properly varying these three scalars, the final point of the line may be made to coincide with any point in space. But if there be a given relation between the scalars, then the number of points will be limited, and the whole number of the points constitutes the locus of the original concrete equation referred to the accessory abstract equa- tion. The consideration of this entirely new view of coordinate geo- metry is reserved for a second memoir. Proceeding next to the laws of clinants, we readily demonstrate that they are the same as the laws of scalars ; they introduce a new conception, however, that of rotating through an angle not .necessarily the same as a semi-revolution, that is, of a plane versor. By the con- crete equation of coordinate geometry, it is immediately shown that all clinants can be expressed as the sum of a scalar, and of the pro- duct of a scalar by a fixed, but arbitrarily chosen versor. The simplest versor to select is the quadrantal versor, which, under the name of quadrantation, is now studied. The two addends of a clinant, considered as a sum, are called its scalar and vector ; its two factors, considered as a product, are its tensor and versor. The laws of these parts are then studied. The statical algebra of clinants has for its object the reduction of all combinations of clinants given in the standard form of the sum of a scalar and vector, to a clinant of the same form. The application of this to the series obtained for a general scalar power, leads to two series, called cosines and sines of the variables, as distinguished from 93 the goniometrical cosines and sines of an angle, with which they are ultimately shown to have a close connexion, which can be rendered most evident by assuming as the unit-angle that subtended by a cir- cular arc of the length of its radius. Studying these series quite in- dependently of these relations to angles, we discover that they bear to each other the same relations as the goniometrical cosines and sines, and that if the least tensor value of the variable for which the cosine series becomes null, is known, all its other values can be found by multiplying this by four times any scalar integer. This last product must be added to the least tensor value of the variable for which both the cosine or the sine series become equal to given scalars, in order to find all the solutions of such equations. Supposing the values of such series tabulated by the method of differences for all scalar values of the variable, so that such least tensor values can always be found, we are now able to assign the meaning of any power whose base and index are both clinants, and the logarithm of any clinant. This enables us to invert completely all the simple for- mations, sum, product, power with variable base and constant index, or constant base and variable index ; and hence to solve all equations of four dimensions with clinant coefficients, and to show that every formation consisting of a sum of integral powers with clinant coeffi- cients, can be expressed as a product of as many simple formations as is determined by the highest index of the variable. The cosine and sine series can also be generally inverted. The versor of any clinant having a known angle (which is always equal to the cosine of its angle added to the product of the sine of its angle into a quadrantal versor), can now be shown to equal the cosine series added to the sine series multiplied by a quadrantal versor, when the variable of the series is the scalar ratio of the angle of the clinant to the angle sub- tended by a circular arc equal to its radius, From this the ratio of the circumference to the diameter of a circle is shown to be twice the least tensor value of the variable, for which the cosine series is equal to null ; and as that value can be readily assigned in a convergent series, the former ratio is determined. The same investigation shows the relation already mentioned between the goniometrical cosines and sines, and the cosine and sine series. Clinant algebraical geometry allows us to interpret all results of clinant algebra when referred to lines on one plane. It thus fur- 94 nishes a complete explanation of the " imaginary " points and lines in the theory of anharmonic ratios, when viewed in relation to the unit radii, as already explained. In the case of coordinate geo- metry of two, and even three dimensions, the possibility of interpret- ing the results of a clinant operation performed on a given unit radius in a given plane, allows us to understand the whole theory of " ima- ginary " intersections. The theory of scalar and clinant algebraical coordinate geometry will form the subject of a future memoir. Proceeding to quaternions, we find their laws to be the same as those of clinants while the plane remains unaltered ; but if the plane is alterable, they cease to be commutative in multiplication, that re- lation being replaced by one between certain related quaternions called their conjugates. This makes the algebra of quaternions (which is not here systematized, as being too recent) entirely different from that of scalars. In mechanics the motion of any point is not considered absolutely as in dynamical geometry, but relatively to some external, constant, independent motion, as the apparent motion of the fixed stars ; this gives the conception of time. But the necessity of considering the motion not merely of a point, but of a body, gives rise to the com- parison of the motions of various bodies, and to a conception of their equality, when the products of their velocities, multiplied by a con- stant which is always the same for the same body, but different for different bodies, are equal. This constant is the mass, which in bodies of the same kind varies as the volume. By considering the case of the mutual destruction of motion, we eliminate time and simplify the problem, thus founding statics; and by conceiving the motion of any body to be destroyed by the application of variable motions equal and opposite to those actually existent, we reduce dynamics to statics. 95 \ June 9, 1859. Sir BENJAMIN C. BRODIE, Bart., President, in the Chair. The Annual General Meeting for the Election of Fellows was held this day. The Statutes respecting the election of Fellows having been read, John Bishop, Esq. and Edward Brayley, Esq. were, with the con- sent of the Society, appointed Scrutators to assist the Secretaries in examining the lists. The votes of the Fellows present having been collected, the follow- ing gentlemen were declared duly elected : — Samuel Husbands Beckles, Esq. Frederick Grace Calvert, Esq. Henry J. Carter, Esq. Douglas Galton, Esq. William Bird Herapath, M.D. George Murray Humphry, Esq. Thomas Sterry Hunt, Esq. John Denis Macdonald, Esq. The Meeting then adjourned. William Odling, Esq. Robert Patterson, Esq. John Penn, Esq. Sir Robert Schomburgk. Thomas Watson, M.D. Bennet Woodcroft, Esq. Lieut.-Col. William Yolland, R.E. COMMUNICATIONS RECEIVED SINCE THE END OF THE SESSION. I. " On the frequent occurrence of Vegetable Parasites in the Hard Structures of Animals." By Professor A. KOLLIKER, of Wiirzburg. Communicated by Dr. SHARFEY, Sec. R.S. Received May 30, 1859. As far as I am aware, Quekett has been the first to point out that vegetable parasites, viz. Conferva, occur frequently in the skeleton of Corals (Lectures on Histology, vol. ii. p. 153. fig. 78. and p. 276) ; but although he mentions in the same place that the tubuli described by Carpenter in the shells of Bivalves have also a great resemblance with Conferva, he did not venture any further step, and he adheres to the view of Carpenter, who regards them as a typical structure. Some years later, Rose ("On Parasitic Borings in Fossil Fish- Scales," Transactions of the Microscopical Society of London, vol. x. 96 p. 7, 1855) discovered a peculiar tubular structure in fossil fish- scales, which he regarded as being occasioned by parasites, and possibly by Infusoria, but he was not able to give any good proof of this hypothesis. The same must be said of E. Claparede (Mull. Archiv, 1857, p. 119), who found similar canals in the test of Neritina fluviatilis, and showed that they do not really belong to the shell, without being happier in determining the nature of the parasite, only suggesting that it might possibly be a sponge. Such was the state of things, when Prof. Wedl of Vienna and I, independently of each other, took up the question. The observations of Wedl, which concern only the parasites of the shells of Bivalves and Gasteropods, were communicated to the Vienna Academy on the 14th of October, 1858, and are therefore previous to my own, which were presented to our Wiirzburg Society on the 14th of May, 1859 ; but I received Wedl's memoir only on the 16th of May, and may therefore say that my observations, which are also extended over many more groups of animals, were quite independent of those of the Austrian microscopist. This being the case, it may be regarded as a good proof of the correctness of our observations and the truth of our conclusions, that we agree in the principal facts, there being only this discrepancy between us, that Wedl calls the parasites Con- fervce, whilst I regard them as Unicellular Fungi. The botanists will decide this question better than we ; only I beg leave to say, that all the numerous parasites observed by myself were unicellular, and that the sporangia were quite of the same kind as those of uni- cellular fungi. I may further add, that the frequent anastomoses of the parasitic tubes remind one of the anastomoses observed in the mycelium of some unicellular fungi, whereas such connexions have not yet, so far as I know, been observed amongst the Conferva. I now give a short enumeration of the animals in whose skeleton I observed these vegetable parasites. 1. Spongice. Two undetermined species of sponges, which I got through the kindness of Mr. Bowerbank, show a great many parasitical tubes in the horny fibres of their skeleton. These are most elegant and numerous in one species from Australia, in wh'ich the tubes form a superficial network in the outermost parts of the horny sponge-fibres and more straight canals in their interior, and possess a great many 97 round sporangia, which in some cases even showed young outgrowths in form of short ramifying tubes. 2. Foraminifera. In an extensive collection of sections of Foraminifera which I owe to the kindness of my friend Prof. Carpenter, there were many genera which showed numerous filaments of fungi in their test itself, viz. Polystomella, Orbitolina, Heterostegina, Amphistegina, Cal- carina, Alveolina, and Operculina. The last genus shows best that these parasitic tubes, which sometimes are very large, are quite different from the two kinds of tubes rightly described by Carpenter as belonging to the test itself. They generally run at right angles to the finer. tubuli, and are easily distinguished from both kinds of typical tubuli by their irregular course, and by their frequent branch- ing, and even anastomosing. They are absent in many specimens of the above-named genera, and could not be found in Cycloclypeus, Nummulina, and Nonionina. 3. Corals. All the genera of Corals which I investigated contained parasitical fungi, viz. Astraa diffusa, Porites clavaria, Tubipora musica, Corallium rubrum, Oculina diffusa, Oculina, sp., Alloporina mirabilis, Madrepora cornuta, Lobalia prolifera, Millepora alcicornis, Fungia, sp. The fungi were most frequent in the genera Tubipora, Astrcea, Porites, and Oculina, the last three of which contained also many spo- rangia, which in the red coral were very scarce and often wanting. 4. Bivalves. I agree with Wedl that the tubuli described by Carpenter in the shells of Bivalves are all parasites. Many of them agree in every respect with those found in other hard structures of the Inver- tebrata, of whose parasitical nature there can be no doubt ; and even possess sporangia, as those of Thracia, Lima, Cleidothcerus, Anomia, Ostrea, Meleagrina. With respect to those of the genera Litho- domus, Area, Pectunculus, Nucula, Cardium, it is true that their straight course and more regular distribution speak in favour of their typical occurrence ; but as in some cases true parasites also are very regularly distributed through the shells, there can be no doubt that even these do not really belong to the structure of the shells. 98 5. Brachiopods. The test of some Terebratulce shows, besides the large well-known canals, minute tubuli running straight through the fibres. A vertical section of Terebratula australis, which I got from Prof. Carpenter, showed that the minute canals referred to belong to a vegetable parasite of the same kind as those of the Bivalves. 6. Gasteropoda. Nearly all examined Gasteropods, viz. Cerithium tuberculatum, Aporrhais pes-Pelecani, Turbo ruffosus, Murex brandaris, Murex trunculus, Haliotis, Vermetus, Trochus, Littorina littorea, Terebra myurus, Tritonium cretaceum, contained vegetable parasites in their shells, and in some these were as numerous as in the Bivalves, and showed also sporangia. Besides these fungi, the shell of Trochus also contained in its most superficial layers unicellular pyriform algae with green contents. 7." Annelids. Even in this group the unicellular parasites were found, viz. in the calcareous tubes of two Serpulce from the Scotch coast. 8. Cirrhipeds. The same parasites also occurred very numerously in the shells of a large Balanus. On the other hand, the genera Diadema and Lepas were free from them ; and with regard to the straight tubes of Polli- cipes described by Quekett, which also occur in Tubicinella, I am inclined to reckon them amongst the typical structures. 9. Fishes. The scales ofBeryx ornatus, from the clay, contain very numerous and pretty parasitic structures, which almost totally agree with those figured by Rose in his fig. 5. They undoubtedly also belong to the simplest form of fungi, but are of greater interest, inasmuch as they are fossil and seem to constitute a new genus. I was not able to find parasites in any other fish-scales, notwithstanding that I examined scales of all living and many fossil species of Ganoids and many Teleostei. These are the facts which I have been able to gather, up to this time. I have no doubt that all will ageee with me in regarding this question as one of great interest for the zoologist as well as for the botanist. The former will now be obliged to study these parasitical 99 structures as thoroughly as possible, in order to decide which tubular structures of the hard tissues of animals are typical and which are not ; and for the botanist a new field of investigation is opened, which not only draws attention by the somewhat strange forms offered for investigation, but is also of great interest in a physiological point of view. It seems to me probable that the parasites dissolve the car- bonate of lime of the hard structures into which they penetrate, by means of exudation of carbonic acid, which secretion would seem to take place only at the growing ends of the fungial tubes, as they never lie in larger cavities, but are always closely surrounded by the calcareous mass. In some cases, as in the horny fibres of sponges, it seems probable that the parasites simply bore their canals by mechanical force, as is the case when vegetable parasites make their way through the cell-membranes of Conferva or other plants. Besides this, it deserves also to be remembered that nearly all the parasites here spoken of occur in marine animals. In concluding this notice, I may further mention that these parasites afford an excellent means for demonstrating the double- refracting power of the shells of the several genera mentioned in this communication. I was first struck with this fact in examining a horizontal section of Lima scabra obtained from Dr. Carpenter, and finding that many tubuli appeared double. In following this matter, it was easy to show that all the tubuli running in a certain direction, and in an oblique way through the section, appeared simple at the upper surface of it, and became double in the inferior layers, so that the distance of the two images increased with the shortening of the focus. When the preparation was inverted, the reverse was the case. The same phenomena as in Lima were also observed in Anomia, Ostrea, Murex truncatus, Turbo rugosus, Tritonium cretaceum, and Balanus, the shells of which animals have therefore all such a structure, that they refract the light in the same way as the well-known double-refracting crystals*. * According to Brewster (Bibl. Univ. de Geneve, 1836. ii. 182), who seems the only person who has hitherto observed the double-refracting power of a shell, viz. of the mother-of-pearl, that shell (Meleagrina) shows the same phenomena as the double-axed double-refracting Arragonite, on which question I am not as yet able to give an opinion. TOO II. " Researches on the Phosphorus-Bases." — No. VI. Phos- phammonium-Compounds. By A. W. HOFMANN, LL.D., F.R.S. &c. Received June 1, 1859. In several previous communications * I have shown that dibromide of ethylene is capable of fixing either one or two molecules of tri- ethylphosphine, a monatomic and a diatomic bromide being formed, which I have respectively represented by the formulae — Monatomic bromide. Clfl H19 PBr2= (C4 H4)" Br2+ (C4 H5)3 P= SH; • 1 *~* .(cU'Br)] j and Diatomic bromide. CM H34 P2 Br2= (C4 H J" Br2 -f 2 ((C4 H5)3 P) = Br Br There are other products formed, resulting from secondary reactions. It was not quite easy to obtain a sufficiently satisfactory experi- mental foundation for the diatomic nature of the second compound. This substance presents an extraordinary degree of stability ; in its general characters it is closely allied to the numerous monatomic bromides, both of the nitrogen- and of the phosphorus-series, which in the course of these researches have come under my consideration. Lastly, the oxygenated derivative of the bromide resembles so per- fectly the monammonium- and the monophosphonium-bases, that more than once during my experiments I was inclined to doubt the correctness of my interpretation. There is no direct proof of the diatomic character of the com- pound. Why should we reject the simple formula deducible from experiment ? The hydrocarbons Cn Hn are very prone to molecular transformations without change of composition. The idea suggested itself, that the diatomic saline molecule might be split into two monatomic saline molecules, [(C. H5)6 (C4 H4)» P.]» Br2=2 ([(C.H.), (C2H2)' P] Br). * Proceedings, vol. ix. pp.285 and 631. 101 It is true C2 H2 figures in this formula as monatomic, whilst we should expect it endowed with diatomic substitution-power. But the connexion between composition and substitution-power is by no means finally settled ; in fact, we know of many cases in which, under conditions not sufficiently established, the atomicity of a mole- cule changes : witness the radical " allyl," which is capable of re- placing one or three equivalents of hydrogen. But without going this length, the scission of diatomic ethylene into two monatomic molecules may take place in many other ways. The transformation of dibromide of ethylene into hydrobromic acid and bromide of vinyl, (C4 HJ" Br2=HBr + (C4 H3) Br, is a familiar example. The splitting of the ethylene-compound into bromide of formyl and bromide of methyl, (C4 HJ" Br2= (C, H) Br+ (0, HJ Br, has never been observed, but did not appear altogether unlikely. Our analytical methods are insufficient to distinguish between [(C4 H5)s (C, HJ P] Br and [(C4 H5)3 (C, H) P]Br ; and what I have represented as a diatomic ethylene-compound might have been, after all, a monatomic bromide — the bromide of formyl-triethylphosphonium, the complementary methyl-compound [(C4H5)8(C2H3)P]Br existing possibly among the secondary products of decomposition. In the presence of these and several similar self-raised objections, bv which every observer endeavours to test the truth of his con- clusions, I was induced again to appeal to experiment. The prosecution of this line of the inquiry has led me to the disco- very of a new class of diatomic bodies, which, while it confirms incon- testably the correctness of my interpretation, appears to claim the attention of chemists for several other reasons. I have established, in the first place, that the monatomic bromide [(C4H5)3(C4H4Br)P]Br may be readily converted into the diatomic bromide [(C4H5)6(C4H4)''PJ»Br2 by the simple addition of triethylphosphine. Nothing is easier than to prove the transformation, the platinum-salt of the two bases pre- VOL. x. i 102 senting a remarkable difference of solubility, and other differences not less striking. To remove every doubt, the bromide, obtained by treatment of the brominetted bromide with triethylphosphine, was converted into the corresponding iodide, which in its properties and composition was found to be identical in every respect with the characteristic iodide, which I have fully described in my last note upon this subject. The transformation of the monatomic into what I have represented as the diatomic compound being satisfactorily established, the con- clusive experimental demonstration of the diatomic nature of the latter presented itself without difficulty in the conception of bromides containing at once phosphorus and nitrogen, the molecular expression of which would no longer admit of division. This class of dibromides actually exists ; they are readily produced by submitting the bromide of the brominetted body to the action of ammonia or monamines instead of triethylphosphine. I have formed as yet only three representatives of this new class of bodies, which I propose to designate as phosphammonium-com- pounds ; their examination is sufficient to fix the character of the class ; it would have been easy to construct scores of similar bodies. Action of Ammonia upon the bromide of the brominetted body. The two substances, especially when in alcoholic solution, unite with evolution of heat — [(C1H5)s(C1H4Br)P]Br+HJN= (C.H.). (C,H4)'' H, N Br, Both the bromide and the corresponding chloride are very soluble, and little adapted for analysis ; I have therefore fixed the nature of this body by the preparation and analysis of the platinum-compound. For this purpose the bromide generated in the above reaction was treated with oxide of silver ; it is thus converted into a powerfully alkaline solution obviously of the dioxide, (C4H5)3 (C4H4)" H, P N H2~ 103 which, saturated with hydrochloric acid and mixed with dichloride of platinum, furnished a light-yellow crystalline platinum-salt, recry- stallizable from boiling-water, and containing [(C4 H5)3 H3(C4 H4)" PN]" C12, 2PtCl2. Action of Etfiylamine and Trimethylamine upon the bromide of the brominetted body. The phenomena observed with ethylamine and trimethylamine are perfectly analogous. These substances furnish, with the bromi- netted bromide, new and very soluble dibromides, containing re- spectively (C,HS)3 (C4H4)» (C4H3)H5 Br2 and Br. which, by treatment with oxide of silver, are converted into the cor- responding powerfully alkaline oxides (C4H5)3 (C4H4)" (C4H5)IL O, and yield, by saturation with hydrochloric acid and precipitation with dichloride of platinum, two splendid platinum-salts crystallizing in long golden-yellow needles, and containing respectively [(C4 H5)4 (C4 H4)" H2 PN]" C12, 2Pt C12, and [(C4 H5)3 (C2 H3)3 (C4 H4)" PN] " C12, 2Pt C12. By the formation of the phosphammonium-compounds, the nature both of the diammonium- and of the diphosphonium-series appears to me finally established. It will be interesting to ascertain whether the brominetted bromide, when submitted to the action of monarsines and monostibines, will give rise to the formation of phospharsonium- and phospho-stibo- The solution of this question will not be difficult. mum- 104 III. " Notes of Researches on the Poly-Ammonias." — No. VI. New Derivatives of Phenylamine and Ethylamine. By A. W. HOFMANN. Received June 9th, 1859. Some time ago* I communicated to the Royal Society some re- sults obtained in studying the action of dibromide of ethylene upon phenylamine. The principal product of this reaction was found to be a well-defined crystalline compound with basic characters. By the analysis of the base itself, and of several of its combinations, it had been proved that the formula p TT AT (C4H4) I jjf ^is "9 w — r; TI f W V/12 n5 ) is the simplest atomic expression for the new substance ; but the action of iodide of methyl and of ethyl upon this body having given rise to compounds and r I was induced to assume the formula /n TJ a '32 as representing the true constitution of the basic body, which thus appears as a diammonia, in which 2 equivs. of hydrogen are replaced by 2 equivs. of phenyl, and 4 equivs. of hydrogen by 2 molecules of diatomic ethylene. This view involves the existence of a basic compound, C28H16N2=(C12H5)JN2, H2 i.e. of a diphenyl-diamine in which only one molecule of diatomic ethylene has been substituted for hydrogen. Experiment has not failed to realize the body pointed out by theory. A mixture of dibromide of ethylene with a large excess of phenylamine (1 vol. of dibromide of ethylene and 4 vols. of phenyl- amine) rapidly solidifies to a crystalline mass. Treatment with * Proceedings of the Royal Society, vol. ix. p. 277. 105 water removes from this mixture a very considerable proportion of hydrochlorate of phenylamine, leaving a brown resinous substance, which gradually but imperfectly solidifies. This substance forms a hydrochlorate which is difficultly soluble in concentrated hydro- chloric acid, and which may be readily purified by repeated crystal- lizations from boiling alcohol. The pure hydrochlorate dissolved in water, and mixed with potassa or ammonia, furnishes the free base, which generally separates as an oil, rapidly solidifying into a cry- stalline substance. This may be further purified by repeated crystal- lizations from diluted alcohol. Analysis, in fact, assigns to this body the formula C28H16N2=(C12H5)JN2, H2 which was confirmed by the analysis of the dichloride — F( as will be seen from the following table :— * Cl I. II. Cia.... 47-84 4776 Hir... 7-30 7-31 O4.... 21-28 Cl .... 23-58 .. 23-88 The reaction, to which the formation of this body is due, may be thus explained : — l Chlorbutyrine of glycol, as I may call this compound, has a pun- gent and somewhat bitter taste. It boils at about 190°. Its specific gravity at zero is 1*0854. It is insoluble in water, but freely soluble in alcohol. It is decomposed with difficulty by a boiling solution of potash, but readily by solid potash, — chloride of potassium, butyrate of potash, and oxide of ethylene, being formed. I have ascertained that acetobutyrate of glycol, the ether I have VOL. x. K 118 already described, can be prepared from this body as well as from chloraeetine, by exposing it to the action of acetate of silver. The process is the same as that I have already given, with this difference, that the reacting bodies must not be heated above 150°C. The ether prepared in this manner gave the following numbers on ana- lysis : — Theory. Experiment. CM.. ..55-17 56-29 Hu. . . . 8-04 8-75 O8 .. ..36-79 The quantity of this substance at my disposal was so small (the greater part of my product having been lost) that I could not purify it completely ; hence the experimental numbers do not exactly accord with the theoretical. Action of Hydrochloric and Benzoic Acids on Glycol. — Formation of Chlorbenzoate of Glycol. A mixture of equivalent quantities of glycol and benzoic acid, pre- viously fused and powdered, was exposed to the action of dry hydro- chloric acid gas for several heurs, the mixture being maintained at the temperature of 100° during the action of the acid, as in the case of the former compounds. The product thus formed presented the appearance of a soft white solid, and contained a considerable quan- tity of uncombined benzoic acid. This was removed by agitating it with hot water, till, on cooling, it no longer became solid, but re- mained perfectly fluid. Finally it was dissolved in alcohol, and pre- cipitated by water. The body thus prepared, and without being distilled, was analysed, having been previously dried in vacuo over sulphuric acid. Another specimen, prepared in the same manner, at a different time, was also analysed, having, however, been previ- ously distilled. During the distillation it was observed that not a drop of fluid passed over till the mercury had risen to 254°, and be- tween that temperature and 270° the entire liquid distilled over. What passed over between 260° and 270° was collected separately ; this was the portion analysed. The numbers obtained on analysis C IT ) agree with the formula Q4 jj Q \ O2> as tne following table shows : — 2ci 119 Theory. Experiment. Portion distilled. I. II. C18 58-54 59-70 .. 58-69 H9.... 4-87 5-01 5-31 O4.... 17-35 .. .. * %'.••• Cl.... 19-24 ;;T. ' 17-93 ;;lv; 100-00 The portion not distilled contained doubtless a trace of free ben- zoic acid, which would affect the carbon and chlorine, but not the hydrogen. Chlor-benzoate of glycol, as I shall call this compound, has a pungent and somewhat bitter taste. It is insoluble in water, but freely soluble in alcohol and ether. Boiling solution of potash effects its decomposition with difficulty, solid potash readily, the re- action being the same as in the case of the analogous compounds. Action of Hydriodic Acid on Glycol. — Formation of Iodide of Ethylene on lodhydrine of Glycol. Hydriodic acid gas is absorbed with great energy by glycol. A considerable quantity of heat is evolved during the passage of the gas, and the liquor becomes black and thick from the separation of free iodine. On removing the iodine by means of dilute potash, a mass of small white crystals is brought to light, which I at once suspected to be iodide of ethylene. To remove all doubt on this point, I submitted the crystals to analysis, having previously purified them, by recrystallizing from boiling alcohol. The numbers ob- tained agree with the formula of iodide of ethylene : — Theory. Experiment. C4.... 8-51 8-73 H4.... 1-42 1-78 I, . 90-07 100-00 The reaction which causes the formation of iodide of ethylene may be thus explained : — That the action of hydriodic acid on glycol should be different K 2 120 from that of hydrochloric acid is doubtless owing to the bond of union between hydrogen and iodine being much weaker than that between hydrogen and chlorine. If, on the other hand, the temperature of the glycol be prevented from rising during the passage of the hydriodic acid gas, by sur- rounding the vessel containing it with cold water, a liquid product is obtained, which is coloured dark-brown by free iodine. This I have not as yet been able to discover any means of purifying, it being soluble in water, and decomposed by distillation. I believe, how- ever, it is the compound corresponding to chlorhydrine of glycol 4 4 °2 discovered bv M- Wurtz- A portion of this liquid, 4 1 °2) di Cl from which I had simply removed the free iodine, by agitation with mercury, gave, on analysis, numbers agreeing tolerably well with the formula of iodhydrine. After the analysis, however, I discovered that it contained a considerable quantity of iodide of mercury in solution. Another portion, from which I had removed the iodine by means of metallic silver, gave, on analysis, 1 1 • I per cent, carbon and 3*5 hydrogen, instead of 13*9 carbon and 3'0 hydrogen. After all, an analysis is not necessary to enable us to arrive at the composi- tion of this body. The products formed by the action of potash on it furnish us with almost as convincing a proof of its composition as any analysis could do. They are iodide of potassium and oxide of ethylene. Iodhydrine cf glycol is soluble in water and alcohol, but insoluble in ether. It has no taste at first ; after a time, however, it almost burns the tongue, it is so pungent. It is decomposed by heat into iodide of ethylene, and probably glycol. It acts with great energy on the salts of silver. Action of Hydriodic and Acetic Acids on Glycol. — Formation of lodacetine of Glycol. A stream of hydriodic acid gas was conducted into a mixture of equivalent quantities of glacial acetic acid and glycol, the tempera- ture of which was prevented from rising during the action of the gas. As soon as a portion of the liquid gave a considerable quantity of an oily precipitate on the addition of water, the passage of the gas 121 was interrupted ; for the prolonged action of the gas is apt to give rise to the formation of iodide of ethylene. The liquid thus obtained was well washed with very dilute potash, dried in vacuo, and ana- lysed. The numbers obtained lead to the formula p4 „* ^ will be seen from the following table : — Theory. Experiment. I. II. 21-95 22-30 3-31 3-50 100-00 lodacetine has a sweetish pungent taste. It is insoluble in water, but soluble in alcohol and ether. Its specific gravity is greater than that of water. It crystallizes in tables when exposed to cold. Heated with potash, it gives iodide of potassium, acetate of potash, and oxide of ethylene. It is readily decomposed by the salts of silver. This compound can also be prepared with great facility by ex- posing monoacetate of glycol to the action of hydriodic acid gas. The liquid must be kept cold during the action of the gas, which should be interrupted as soon as the addition of water to a portion of it causes an abundant oily precipitate. The whole is then washed with dilute potash, and dried in vacuo. A specimen prepared in this manner gave, on analysis, 22*62 per cent, carbon and 3*43 hy- drogen, instead of 22-42 carbon and 3-27 hydrogen. I hope soon to have an opportunity of studying these iodine com- pounds more particularly. Action of Anhydrous Acetic Acid on Glycol, — Formation of Mono- acetate of Glycol. A mixture of equivalent quantities of anhydrous acetic acid and glycol was heated in a sealed tube for several hours at a temperature not exceeding 170°C. On opening the tube, and submitting its contents to distillation, it was observed that the mercury remained stationary for a considerable time at about 120°, the point of ebulli- tion of glacial acetic acid, and then rose rapidly to 180°, between which and 186° the remainder of the liquid passed over. 122 This was analysed, and proved to be pure monoacetate of glycol. Theory. Experiment. C8 46-15 46-02 H8. ... 7*69 7-80 O, 46-16 100-00 The following equation will explain the reaction which takes place between the acid and the glycol : — Qi H4 \ ^ , C4 H3 O2 \ o _ p4 TT4 Q I Q , C4 H3 O2 } Q H2J 4 C4H3OJU2 4H2|U4+ H JU2' The foregoing experiments were performed in the laboratory of M. Wurtz. VI. " Experiments on some of the Various Circumstances in- fluencing Cutaneous Absorption." By AUGUSTUS WALLER, M.D., F.K.S., Professor of Physiology, Queen's College, Birmingham. Received June 27, 1859. In some former experiments* I endeavoured to elucidate the phse- nomeria of cutaneous absorption on the lower animals (batracia), by immersing the hinder extremities in various solutions, and afterwards watching the period at which the absorbed substances reached the tongue, where their presence was detected by means of some reagent applied to its surface ; as, for instance, a salt of iron, when the legs were immersed in a solution of yellow ferro-cyanide of potassium ; Prussian blue was then formed as soon as the ferro-cyanide was brought to the tongue. Furthermore, I was able to detect, by the aid of the microscope, the "lieux d' election," or preference spots, where the cyanide escaped from the vessels. On the present occasion I shall endeavour to elucidate cutaneous absorption on the higher animals, and, if possible, to give a more definite view of this function, by determining, by accurate measure- ment, the degree of rapidity, the peculiarities, &c., which it may offer in various conditions. * Waller " Absorption of various substances through the skin of the Frog." — Frorieps Tagesberichte, 1851. 123 A very simple mode of demonstrating the existence of cutaneous absorption is by immersing the leg of a young guinea pig, not more than half-grown, into a mixture of equal parts of chloroform and tincture of aconite. After 15 minutes' immersion, the part will be found insensible at the surface and extremities, and, after a short time, symptons of poisoning by aconite will supervene, viz. : nausea, efforts at vomiting, sometimes vomiting of bile, coldness of the surface and extremities, circulation very weak, laborious respiration, slight convulsive symptoms, and death. The influence of age, or of thickening of the cuticle, is easily seen in the same way ; for, if instead of a young animal we take an adult one, we obtain no poisoning, but merely local insensibility and slight disturbance of respiration, &c. Another not less instructive experiment consists in replacing the mixture of chloroform and tincture of aconite by simple tincture of aconite. In this case, the limb may be indefinitely immersed without our obtaining either local insensibility, or death, or indeed any symptom whatever of the presence of aconite in the system. A fourth experiment, which consists in dividing the sciatic nerve, shows the influence of innervation on the function of absorption ; for, if performed on an adult animal, and consequently one incapable of absorbing aconite in quantity sufficient to cause death, the powers of absorption will be generally found so much augmented that the animal will be poisoned by immersion of the limb in simple tincture of aconite. In this experiment I attribute the acceleration in the cutaneous absorption to the paralysis of the blood vessels, as in my experiments on the sympathetic nerve, where I showed that in blood vessels the passage of the blood is completely regulated by nerves springing from the spinal cord. When the vascular nerves are paralysed, the artery becomes greatly distended, and the blood flows faster within it. The foot after the section of the sciatic is, on this account, more hot and red ; and for the same reasons it is easy to account for the more rapid absorption of medicinal agents. A fifth experiment consists in placing a ligature on the limb, in order to impede the powers of absorption of the animal. Although the ligature does produce this result, I was rather surprised to find how much less efficient it was than is generally represented ; for, 124 whenever the least symptoms of a toxic influence made their appear- ance, a ligature placed over the limb rarely succeeded in saving the animal. In order to obtain results more susceptible of measurement, I pro- ceeded to substitute atropia for aconite, and to make use of the albino rat in lieu of the guinea pig. By this means, I possessed an agent whose intervention was immediately detected by its action on the iris. My choice of the albino rat was for the like reason, f. e. the facility which it offered for exact and easy measurement, in which respect this animal is far preferable to any other with which I am acquainted, unless we except the white mouse, which, however, is so liable to die from slight causes, that it is little adapted for most physiological experiments. The modus operandi which I generally adopt is to immerse the limb into a small 2-drachm bottle containing sufficient of the mixture to cover the foot and part of the leg. The strength of the solution of atropia being generally that from half a grain to one drachm of some menstruum, such as chloroform, alcohol, &c., I generally prefer simply to hold the animal during the experiment to any other mode of restraint. By these means I am able to guard against several causes of error, such as the direct contact of the solution with the eye or mouth, and, at the same time, avoid any unnecessary dis- comfort to the animal. Chloroform and Atropia. — A solution of atropia in chloroform will generally be found to cause dilatation of the pupil after the foot has been immersed from two to five minutes. The dilatation, having once commenced, is usually very rapid, and the pupil very soon attains double or treble its normal diameter, which is about J to ^ a millimetre during day-time. It is easy to recognize that this dilatation is not in very simple ratio to the time occupied in its expansion, the expansion of the pupil being more nearly in proportion to the square of the time occupied than in a simple arithmetical ratio. Immersion of one limb causes both pupils to dilate equally, except in some few instances, where one pupil expands much more than the other, from some con- stitutional peculiarity, which remains the same whichever foot be immersed. Although I have never failed to obtain dilatation of the pupils by the immersion of the foot in this solution of atropia, yet, in some 125 cases, it takes place more slowly than in others. The age of the animal has, in this respect, a most marked retarding influence. On animals only about a third grown, it will often occur at about 2J minutes after immersion, while in the adult it generally requires five minutes and upwards. The local effects of immersion are redness, heat, and swelling of the foot, accompanied sometimes with extravasation from some smaller vessels, when the immersion has been prolonged for ten minutes and upward. The sensibility of the part is likewise di- minished, but in no case so as to produce insensibility. The amount of irritation is of course variable, according to the duration of the immersion. It is, however, important to remark that full dilatation of the pupils may be obtained without any symptons beyond those of a temporary active vascularization of the part, which quickly dis- appears when the irritating cause is removed, and which presents no more active symptoms than those produced by neuro-paralysis of the vessels after section of the sciatic nerve. If instead of immersing the limb as above, we merely plunge it for a moment in the solution, we likewise may have dilatation of the pupil, but more slowly. The same effects are obtained even although the limb be washed on its withdrawal from the solution, which would lead to the inference that the effect in that case is owing to absorption of the atropia, at all events beneath the cuticle. In the case of a solution of atropia in turpentine, a still more curious effect is observed, viz. that during immersion in the liquid the pupil scarcely, if at all, dilates ; whereas, immediately after the removal of the limb, the dilatation commences. Dilatation of the pupils will generally persist from twenty-four to thirty-six hours, and the return to the normal size is very gradual. In some cases the pupil may be affected after an immersion of nine minutes, the dilatation reaching three millimetres ; while in others, only a very slight influence is obtained on the pupil after an immersion of from twelve to fifteen minutes. If the limb is then removed from the solution, the pupil dilates to its maximum in a few minutes. After two or three minutes' immersion, the animal shows signs of consider- able pain. Much inflammation of the part follows the action of this solution, which is followed by oedema. When we immerse the tail of the animal instead of its foot, 126 absorption takes place much more slowly, dilatation of the pupil being produced only after the lapse of about twenty minutes. Atropia and Alcohol. — If we substitute alcohol instead of chloro- form as a solvent, we find that absorption is extremely slow. Instead of obtaining dilatation of the pupils in two or three minutes, we find that an immersion of twenty to thirty minutes in the alcoholic solu- tion will only produce very slight effects. At the same time the local irritation is much less than that caused by chloroform. Alcohol of various strength, from proof spirit upwards, had the same result as a solvent. Atropia in watery with the addition of sufficient acetic acid for its solution. — The absorption of atropia in this state is very slow, thirty minutes' immersion frequently producing no dilatation of the pupils. Dilatation is then promoted by removal of the limb from the solution. Watery extract of Belladonna. — When rubbed over the leg and tail, this substance was not found, after the lapse of an hour, to pro- duce any dilatation of the pupil. Tincture of belladonna, with half its quantity of chloroform, pro- duced dilatation at the end of fifteen minutes. The part was found on removal to be completely insensible, and considerably swollen from oedema, which lasted for several days. Atropia with strong alcohol and ammonia produced dilatation of the pupil after twenty-five minutes' immersion. In this case, the ammonia was added for the purpose of ascertaining how far irritation of the part was conducive to absorption. Slight vesication was the consequence of the presence of ammonia. The acceleration of the absorption was very slight, as the solution produced no dilatation until after twenty-four minutes' immersion. Absorption of Morphia. — The foot of a young rat at one- third of its growth was immersed in a solution consisting of half a grain of acetate of morphia in twenty drops of alcohol and one drachm of chloroform. In five minutes the pupils gradually dilated to the maximum ; the limb was then withdrawn ; foot hot, red, and rather swollen. Irritation of the skin caused no cry, the animal merely withdrawing the part. Somnolency existed, from which any noise aroused it, but only for a moment. When placed on its back, the animal remained in that position. Respiration accelerated. Vision when roused very imperfect, as was shown by its falling off the table. 127 The pupils continued fully dilated, the iris being reduced to an almost imperceptible circle, the dilatation exceeding that which I have been able to attain even with atropia. I will not dwell more fully at present on this last interesting fact, which is opposed to what we generally meet with in the administration of morphia. Twelve hours after, pupils normal, animal quite well. Strychnia and Chloroform. — After three minutes' immersion of foot, dilatation of pupils ensued. After five minutes, the immersed limb was very sensitive, apparently more so than normal. Limb removed from solution : spasms about the throat now appeared, which were rapidly succeeded by stiffness of the trunk, increasing into tetanic spasms. Death, two minutes after removal. Strychnia and Alcohol. — Foot immersed in a solution of alcohol and strychnia for upwards of thirty-five minutes ; no symptoms of strychnine poisoning. Removed from solution and washed. Twelve hours later, no dilatation nor contraction of pupils. The above observations evidently show that medicinal substances may be very rapidly absorbed into the circulation under certain cir- cumstances, among which, the most important is the choice of the menstruum in which they are dissolved. It remains for us to examine into the effect of temperature, in- flammation, neuro-vascular paralysis, &c., on absorption. But, what is of still more importance, we have to see how far these facts are applicable to man in health and disease. Meanwhile, I take this opportunity to state that a remarkable uniformity exists between cutaneous absorption in man and in the lower animals, and I believe that the application of these facts to practical medicine promises to be very important and extensive. VII. "On Spontaneous Evaporation." By BENJAMIN GUY BABINGTON, M.D., F.R.S., &c. Received June 7, 1859. - (Abstract.) The object of this communication is to make known certain powers of attraction and repulsion, hitherto, as far as I know, unnoticed, which are possessed by soluble substances in relation to their solvent, and which, in the case of water (the solvent here considered), are measured by the amount of loss, on spontaneous evaporation, in the 128 weight of solutions of different salts and other substances, as compared with the loss of weight in water. The force which holds together the particles of a vaporizable liquid is gradually overcome, if that liquid be exposed to air, by another force which separates, expands, and diffuses those particles in the form of vapour ; and this separation takes place, even at a common temperature, so rapidly, provided the surface be sufficiently extensive, that an easy opportunity is afforded of determining the loss of weight by a common balance. A subject for investigation, possessing much interest, thus presents itself, and, in its pursuit, some new and unexpected results are encountered. The method which I have pursued has been to expose to the atmosphere, for a definite period, solutions of different salts, and also pure water under like conditions of quantity and area, temperature, atmospheric moisture, and atmospheric pressure. Different salts and other soluble substances are thus found to possess, when in solution, different powers of retarding or accelerating evaporation, and hence, from its amount, as compared with that which takes place in pure water, we can estimate the comparative value of those powers. The powers themselves being established as facts, the next point is to endeavour to discover the cause or causes on which they depend, and a wide field of inquiry is thus opened. The following are the instruments which have been employed : — 1 . A balance, for one of the scales of which is substituted a flat metal plate, six inches square, on which the vessels to be weighed can be conveniently supported. This balance will turn sensibly at a grain, even with a weight of 4 Ibs. on either side. 2. A number of copper pans tinned within, all of the same size, being precisely 5 inches square inside, with perpendicular sides f ths of an inch in height, also a number of earthenware pans of the same dimensions, The area of 25 square inches has been chosen, partly because this size is convenient for manipulation, and partly because the results obtained can be easily represented in decimals. This facility of decimal calculation would be of importance should such pans come into general use as hygrometers, for which purpose they are well adapted. 129 3. Specific gravity bottles and counterpoises. 4. Thermometers of various degrees of delicacy and range, for ascertaining freezing, temperate, and boiling points. 5. Test tubes for use, in connexion with these thermometers, as well in freezing mixtures as over the spirit lamp. 6. A barometer. 7. Various salts and other soluble substances, furnishing, when in solution, the materials for examination. The mode of procedure which I have adopted has been, to state my facts in the form of propositions, and to prove each of these propositions by experiments. The propositions are as follows : — 1st proposition. — That in many aqueous solutions of salts and other soluble substances evaporation is retarded, as compared with the evaporation of water. 2nd proposition. — That in solutions of salts which retard evapora- tion, that retardation is in proportion to the quantity of the salt held in solution. 3rd proposition. — That different salts and other substances soluble in water have different degrees of power in retarding its evaporation. 4th proposition. — That the power of retarding evaporation does not depend on the specific gravity of a solution. 5th proposition. — That in aqueous solutions of salts, the power of retardation does not depend on the base, whether we compare solu- tions containing like weights of the salt, or solutions of like specific gravities. 6th proposition. — That in aqueous solutions of salts, the power of retarding evaporation does appear to depend upon the salt radical or acid, although the retardation is not altogether independent of the influence of the base. 7th proposition. — That salts with two equivalents of an acid have a greater power of retarding evaporation than salts with one equivalent. There are, however, exceptions. 8th proposition. — That there are some salts which, being dissolved in water, do not retard its evaporation, and some salts which, so far from retarding, actually accelerate evaporation. The truth or probability of the foregoing propositions is established by numerous experiments, but in this abstract I shall, for the sake 130 of brevity, only state the result of one or two experiments in proof of each. The first proposition is proved by the fact that a solution of hydro- chlorate of soda in the proportion of 480 grains to four measured ounces of water, when exposed under the conditions already stated to spontaneous evaporation, lost only 33 grains in weight after twelve hours' exposure, — while four ounces by measure of water lost 53 grains, — and after twelve hours' further exposure lost only 109 grains, while the water lost 1 74 grains ; that is, the water, as compared with the solution, lost weight in the ratio nearly of 5 to 3. The second proposition is proved by the fact that a solution of 240 grains of hydrochlorate of soda in four ounces by measure of water lost in twelve hours 73 grains by evaporation, while four ounces by measure of pure water lost 81 grains, — this is in a proportion of only about 8 of the latter to 7 of the former ; whereas, when double the quantity or 480 grains of salt were dissolved, the pure water, as compared with the solution, lost in the proportion of 5 to 3. The third proposition is proved by the fact that a solution of 480 grains of nitrate of potassa in 4 ounces or 1920 grains of water lost in twelve hours 95 grains ; while a solution of the same strength of hydrochlorate of soda lost only 70 grains ; and again, a solution of loaf-sugar, in which 480 grains were dissolved in 1 920 grains of water, lost in 20 hours 1 75 grains, while a like solution of hydrochlorate of soda lost only 117 grains. The fourth proposition is proved by the fact that 480 grains of gum-arabic dissolved in 1920 of water had a specific gravity of 1 *072, while a solution of hydrochlorate of soda of like strength had a spe- cific gravity of 1*149 ; after 1 1| hours, the former had lost by eva- poration 71 grains, while the latter had lost only 50 grains. Here, therefore, the solution of the lighter specific gravity was less retarded in its evaporation than the heavier solution. In contrast with this fact, a solution of hydrochlorate of ammonia of 480 grains to 1920 grains of water, having a specific gravity of only 1*060, lost by evapo- ration, in 8 hours and 44 minutes, 1 7 grains, while a like solution of hydrochlorate of soda lost 24 grains. Here, then, the solution of lighter specific gravity was more retarded in its evaporation than the heavier solution. The cdnclusion is decisive that specific gravity has no necessary connexion with the phenomena. 131 The fifth proposition is proved by the fact that in the following solutions of salts of potassa, all of the same strength (namely 1 salt to 10 water), a difference in the amount of evaporation in each will be observed to have taken place, and it must be borne in mind that in solutions so weak we cannot expect that difference to be very great. The reason for employing weak solutions was the necessity for having all of the same strength, one in ten being the extent, to which the least soluble salt submitted to examination, namely, the sulphate of potassa, will, at a low temperature, dissolve. grains. Acetate of potassa lost in 35 hours 145 Bicarbonate of potassa lost in 35 hours . . . 131 Carbonate of potassa lost in 35 hours . . . 115 Ferro-cyanate of potassa lost in 35 hours . . 110 Hydrochlorate of potassa lost in 35 hours . . 98 Nitrate of potassa lost in 35 hours . . . . 117 Sulphate of potassa lost in 35 hours .... 132 Tartrate of potassa lost in 35 hours . . . . 151 The above solutions were next made all of one specific gravity, namely 1'060, temp. 62° Fahr., instead of being all of one strength, and the following is the result : — grains. Acetate of potassa lost in 16 1 hours .... 46 Bicarbonate of potassa lost in 16| hours ... 45 Carbonate of potassa lost in 16| hours ... 35 Ferro-cyanate of potassa lost in 16J hours . .41 Hydrochlorate of potassa lost in 16| hours . . 32 Nitrate of potassa lost in 16| hours .... 39 Sulphate of potassa lost in 1 6 J hours .... 42 Tartrate of potassa lost in 16^ hours .... 43 The sixth proposition is rendered probable by the following ex- periment, in which solutions are employed of acetic, nitric, sulphuric, and hydrochloric acids, combined respectively with potassa, soda, and ammonia, in the proportion of 100 grains of the salt to 1000 grains of water. After the expiration of 10 hours and 20 minutes, the solution of the three acetates lost respectively, for the potassa salt 35 grs., for the soda salt 35 grs., and for the ammonia salt 28 grs. In the solutions of the three nitrates, the loss was re- spectively 24, 25 and 25. In the solutions of the three sulphates, 132 the loss was 30 grs., 37 grs., and 29 grs. respectively, while in the solutions of the hydrochlorates it was 17, 18, and 19 grains. The seventh proposition is proved by an experiment in which a solution of 100 grains of carbonate of potassa dissolved in 1000 grains of water is compared with a like solution of bicarbonate of potassa. In ten hours the solution of the carbonate lost 45 grains, while that of the bicarbonate lost only 36 grains. In comparing like proportions and quantities of sulphate and bisulphate of potassa, the respective losses in 13 hours were, for the former 53 grains, for the latter 45 grains. Similar comparisons of the acetate and bin- acetate of ammonia, phosphate and biphosphate, sulphate and bisulphate of potassa, tartrate and bitartrate of soda show like results. In the course of investigating this proposition it was remarked incidentally that in all the salts examined, with the single exception of carbonate and bicarbonate of soda, the bin-acid solution (the proportion by weight of salt to water being equal) is of less specific gravity than the mono-acid solution, though possessing a greater power of retarding evaporation. The eighth proposition, which seems extraordinary and even paradoxical, is proved by an experiment in which saturated solutions of — 1, ferro-cyanate of potassa, 2, bitartrate of potassa, 3, sulphate of copper, 4, chlorate of potassa, and 5, distilled water, were com- pared. In 9 hours arid 20 minutes, their losses by evaporation were respectively 34 grs., 38 grs., 34 grs., 29 grs., and 29 grs., where we perceive that in the chlorate of potassa solution there has occurred no retardation at all, while in the following experiment, in which 120 grains of each of the salts examined were dissolved in 1200 grains of water, namely, — 1, solution of sulphate of copper, 2, solu- tion of ferro-cyanate of potassa, 3, solution of carbonate of soda, and 4, distilled water, the number of grains lost by evaporation after 15 J hours' exposure were, — 1, 120 grs. ; 2, 113 grs. ; 3, 106 grs. ; 4, 103 grs. It is thus perceived that in all the three solutions a more rapid evaporation had taken place than in distilled water alone. One or two other propositions are in process of investigation. The paper concludes with a table of the freezing-points, boiling- points, and specific gravities, as well of weak as of saturated solutions, of the salts which have been submitted to examination. 133 VIII. " On the Application of the Calculus of Probabilities to the results of measures of the Position and Distance of Double Stars." By THE LORD WROTTESLEY, V.P.R.S., &c. Received May 27, 1859. In a communication addressed to the Royal Society "On the results of Periodical Observations of the Positions and Distances of certain Double Stars," printed in the Philosophical Transactions for 1851, I took occasion to remark that the differences between mean results ob- tained on different evenings were greater in proportion than those of the separate or partial measures obtained on the same evening, which arise from chance errors of observation, and that this circumstance rendered the application of the Formulae of the Calculus of Probabi- lities to the reduction of the observations embarrassing and difficult. In other words, the differences between the mean positions and dis- tances obtained on different nights were greater than would have been anticipated by one who had merely computed the probable error of a single measure in the usual manner from the data furnished by the sums of the squares of the partial differences from the mean. The observations made since 1851 fully confirm the anomaly in question. It is probable, therefore, that there is some cause which modifies sensibly and in some unknown manner the results obtained. It may be temperature acting on the micrometer screw ; it may be the state of the atmosphere or the method of making the observation ; but whatever it be, the observations show conclusively that such causes are sometimes in operation. For the purpose of obtaining some numerical expression, however imperfect, of the effect produced, I adopted the following method : — I took the difference between two mean results of position obtained on two different nights, where not more than about two months in- tervened between the observations ; and I ascertained also the mean of the probable errors of such positions as computed in the ordinary method. In order that each star might be subjected to exactly the same treatment, I selected always the observations of the first two nights on which it was observed, except when the two consecutive means were obtained at too long an interval apart. Now as the number of partial measures of angle obtained on each separate night very often did not exceed six, these probable errors are certainly not VOL. x. L 134 theoretically correct, or to be depended upon absolutely as a test of the accuracy of the observation ; but it may perhaps be assumed that any errors arising from this cause will not materially affect the mean of a very great number of results. It appeared then that the mean of 218 differences taken at hazard from among such as were most accessible, and from observations made by different observers, was 3 7'' 6 7, and that the corresponding mean of the means of all the probable errors was 13ft29 ; that is to say, the latter is 35 -27 per cent, only of the value of the former. As some proof that the cause, whatever it may be, is not very variable in its operation, I may add that the first 110 differences, which were all obtained before the end of 1854, give these numbers, 37'* 79, ll'-86, and 31 '37 per cent, respectively. Again, the last 108 differ- ences, which were all derived from the observations of one observer only, give 37''56, 14f'75, and 39 '27 per cent. Of these 108 last differences, the first 50, taken from the middle epoch of all the obser- vations, give 40'-06, 14f<60, and 36'44 per cent., and the last 58 of the 108 give 35'-40, 14'-88, and 42-03 per cent. There is, however, a circumstance which must be taken into account in making a com- parison between the first 110 differences and mean probable errors, and the last 108. During the course of the observations from which the former were derived, it was the practice to take always 10 mea- sures of each star on each night when possible ; during the observa- tions from which the latter were derived, 6 measures only were taken. This would tend to make the differences less in the former case ; and with respect to its effect on the probable errors, if we put F for the error of a single measure in each case, the probable errors in the former case should be less by a quantity = 0'0768xF; for if we put C for the constant and P for the probable error, then we have P= — = xF, where 6 measures are obtained; and P= — =xF, \/45 -V/45 where 10 are taken ; and the difference between these values = •0768 F. The facts above disclosed create the difficulties in applying the Calculus of Probabilities which have been before referred to. In the first place, the partial measures obtained on each separate night are generally too few in number to eliminate the effects of one- sided chance errors. 135 In the second place, it seems probable that some cause remains in action during a whole night, modifying the result, whose origin and law remain to be discovered, but which seems tolerably constant in its operation. The observations of my Catalogue of double stars are drawing to a close, and it became extremely desirable that if there were any fault in the reductions or method of computing hitherto employed it should be speedily remedied, and the necessary corrections made ; I therefore applied to the Astronomer Royal, stating the embarrass- ments arising from the above-mentioned causes, and requesting his opinion as to the best mode of proceeding. The Astronomer Royal exhibited on this, as on all other occasions, where his aid has been solicited, the greatest readiness to give me the benefit of his extensive knowledge of all that appertains to Astronomical science. Mr. Airy observed that if there were a constant cause of error on any night, no multiplication of observations on that night would tend to remove it, and in that case he knew of no mode of proceeding which would quite meet the difficulty but the adoption of the follow- ing formulae. Assuming that all the observations are equally good, or can be made so by grouping discordant measures, let f be the probable error of a single observation, and e the probable value of the error of each night. Let S15 S2, S3, &c. represent the sums of the squares of the errors obtained in the usual manner from the observations on the first, second, third, &c. nights respectively, and put nlt n2, &c. for the number of observations obtained on each of those nights ; then the observations of the first night give, -4549x8,; those of the second, (W2-l)/2=-4549xS2, and so on: and from the sum of all these equations /may be accu- rately determined. Then to find e, compare the mean result obtained from the obser- vations on all the nights, i. e. the mean of all the means, with the separate means for separate evenings ; then putting S for the sum of L2 136 the squares of the errors found by such comparison, and m for the whole number of nights, we have (m-1) e2='4549xS, which gives the value of e. If A be taken to represent any convenient constant, the combining weight for each of the first night's observations will be — 5 — — , for iii" ~\j A each of the second night's — - — - , and so on. Let P stand for the probable error of the final result, then 1 P= \/u • - V+/2 n^ The probable error of the mean of the first night's observations •^-j, of the second=A / [ e*-\-l— ), &c. Mr. Airy, however, while remarking that the mode of proceeding above described is the only one which really meets the difficulties of the case, admits at the same time that it would not be expedient to use so elaborate a process in dealing with observations like those in question, in which the ordinary errors of observation are large in amount, and in which such extreme accuracy in the results is not obtainable as in some other cases to which the principles of the Calculus are applicable. He suggests therefore that all the observations of all the several nights should be combined together for the purpose of obtaining the probable error and weight of the final result ; and this may be done in two different ways :-^First, by treating all the single measures of all the nights, as if they had been made on one and the same night, and obtaining the final result and its probable error and weight ac- cordingly in the usual manner : Secondly, by treating each group or set of 6 or 10 as a single observation. The only other method of proceeding is that above described as the correct one, but which has not been adopted, as being too cumbrous for the occasion. This will be designated as the Third Method. For the purpose of ascertaining the result of employing each of 137 these three methods, I requested my assistant, Mr. Morton, to ob- serve three stars, selected from among those which present only average difficulties, a very great number of times, so that the measures should be sufficiently numerous to eliminate all one-sided errors. The observations of Position only have been used ; but these have been dealt with in the three different methods above described, that is, the final result and its probable error and weight have been ob- tained by each of the three modes. The results are here subjoined, and the errors and their squares are given in full as to two of the stars, together with the whole computation ; and it is to be hoped that this may not only prove interesting to observers of double stars, but may throw some light on the curious mathematical question in- volved in the inquiry which is the subject of the above remarks. Among the stars selected as above mentioned for the trial of the three methods, was 2 Comae Berenices, or S 1596. Now this star had been very frequently observed during the six years from 1843 to 1848, at the time of the Parallax investigation, to which reference has been already made. The comparison then made between the mean of all the measures of position obtained and the value of the angle of position given by Struve, gave reason to believe either that the angle had not altered during a period of sixteen years, or at least that it had altered very little. The observations of 1859 fully con- firmed this opinion. Rejecting from the observations of 1843-8 those made on two nights, when less than 6 measures were obtained, the result of 1859 differs only 8' from that of 1843-8. I was thus enabled, for the purposes of this inquiry, to treat these observations of 1843-8, 156 in number, as if they had all been made within an interval of time not greater than about two months. Now these observations had been made by three different observers, and while the results of separate nights were very discordant, the probable errors derived from the partial values of nights, the results of which differed greatly from the general mean, were as remarkably small ; on the other hand, the observations of the same star in 1859, 215 in number, were by one observer only, and the results of different nights agree very closely. The applications of the three methods to the early and late observations of this star therefore illustrate yery strikingly the effect produced by discordancy in the values obtained on different nights, when the peculiarities of the object observed 138 are eliminated. Thus the good observations of 1859 give the ea equal to 89' only, while in those of 1843-8 the ea attains the great value of 8731'. The values of/2 given by the observations of the three stars accord very well, considering the different circumstances under which they were obtained. It will be seen also that little effect is produced on the mean result by using these different methods of reduction. In the account of the American Coast Survey of 1856, and at pages 307-8, will be found a formula by which the probable error is deduced from the differences from the mean alone, the probable error or P=0*845347 — , where e represents the error of a single observation. I have tested this in the case of three stars in which n was equal to 6, 10, and 156, respectively, and the probable error deduced was a little greater in the first two cases, and a very little smaller in the last. 139 Computation of P by Method 1 for S 1596, 2 Com. Ber. Epoch. Sum of Measures No. of Meas. o 1859-238 22 2 10 •24 9 5 6 •244 21 4 10 •244 15 44 10 •244 17 25 10 •244 20 10 10 •260 13 3 10 •260 13 42 10 •260 14 27 10 •260 26 I 10 •260 20 48 10 •263 13 28 9 •288 16 45 10 •288 22 24 10 •290 '5 15 10 •293 II 40 10 •293 18 4 10 •293 21 49 10 •296 12 I 10 •296 16 26 IO •296 24 30 10 •296 21 35 10 22)1-547 389 50 -f2I5 1859-270 = i 49 + 30 o 3i 49 Zero -450 19 418 30 238° 30' = Mean Position. Error A Error e2. Errors. e2. Error e3. 36 129 82 672 32 102 53 2809 75 562 26 67 40 1 160 '37 18769 39 "5 1322 21 44 22 484 42 176 59 348 48 j 230 18 324 46 211 15 22 63 396 19 36l 8 6 19 36 23 52 20 400 42 176 12 144 6 3 2 4 7? 8 577 167 84 2788 29 84 61 J 372 65 58 4225 3360 42 176 34 "5 83 688 3 9 58 336 33 108 14 19 20 400 23 52 53 280 33 108 9 gj 54 2916 68 462, 14 19 33 1089 35 1225 94 883 31 96 86 7396 12 144 68 4624 71 i 5041 79 6241 5 2' 25 62 88 7744 33 1089 151 22801 35 122 102 1040- IOO IOOOO 89 7921 3 69 4761 104 10816 6Z 3721 I02< 13 l69 169 63 3969 21 441 11 1225 3600 47 22O9 78 6084 40 1600 10 IOO 34 II56 13 l69 29 841 8 64 47 2209 39 1521 5 25 61 3721 67 4489 126 15876 17 289 57 3249 84 7056 78 6084 10 IOO '7 289 5 25 58 3364 32 1024 58 3364 19 36l 79 6241 102 IO40^ 7 49 3 5 64 4096 48 230, 289 49 2401 IOO 10000 20 400 83 6889 37 1369 5 2' 95 9025 41 1681 35 1225 134 17956 23 529 117 13689 94 8836 I I 74 5476 5 25 39 1521 14 196 J34 17956 35 1225 34 1156 21 441 91 8281 0 0 25 625 82 6724 68 4624 85 7225 35 | "25 41 1681 56 3136 113 12769 27 729 61 3721 196 26 676 86 7396 24 576 109 3721 11881 48 105 2304 11025 54 2916 65 4225 51 27 2601 729 128 16384 20 400 127 16129 32 1024 89 7921 52 2704 8 64 181 32761 54 2916 31 961 92 8464 i i 121 4641 28 784 56 12 144 44 1936 85 7225 16 256 77 5929 131 7161 109 11881 16 256 31 961 98 9604 204 41616 94 8836 87 7569 17 289 149 22201 10 IOO 73 5329 o o 103 0609 149 76 22201 74 58 5476 94 8836 1 A T T ffl H5 2IO25 / 68 4624 69 4761 34 **5° 47 2209 689I . 92 8464 58 3364 25 6z5 2076 23 529 93 8649 23 529 6740 5o 250C 35 1225 30 900 41952 41952 6740 152076 Se'= 7659 140 Method 1 (continued). Log. of 937659 = 5-9720449 Constant = 6-9950980 p - 3''°45 Log. of 2 1 5 Log. of 214 = 0*9671429 = 0-4835715 = 2-3324385 = 2-3304138 4-6628523 Log. of -454936 = 1-6579503 4-6628523 Constant = 6-9950980 Method 2. Mean Position = 238° 30'. Errors. e2. Errors. A 26 676 19 361 10 100 8 64 21 441 »5 625 »5 225 *7 289 4 16 39 1521 12 144 i i 28 784 22 484 27 729 37 1369 22 484 10 IOO 47 2209 38 1444 16 256 21 441 6064 f99 6064 Se2= 12763 15063 = 8! 7583=82 218206 = 83 241621 = 84 24012 = 85 48249 = 8,, 34511 = 8; 85199=83 245830 = 89 920274 Log. of 12763 =4-10595 »=22, Constant =4-99331 i -09926 =\ of P2 °' 54963=^ of P P2=I2'-568 p = 3'*545 W= -0796 Method 3. Log. of 920274 =5*963917* Log. of C='4549 &c.= 7-6579503 5-6218675 Log. of 206 =2-3138672 = 3-3080003 • 141 Method 3 {continued). f>]— J3 i y 15 7O 01 — 0 bn b — 20 & ^1 — 0) * = = 070 IOO fc: 1 T " ! I b3-b b.-b - 16 n i j b, — 7i TO b* — b _ 36? "5 31 0*~ 1 1 C7 bK—b _ 6l 72 _ 17 ?8o fti — •7 T 47 b*—b _ 6 76 ba—b £ = 31 49 S = 1560 See Method 1. Log. of 1560 = 3-1931246 Constant Log. = i*6579503 2-8510749 Log. of 8 = m — i = 0*9030900 •71 = 1-9479849 0x88-74-2032; ' \6x 887+2032 k5oX 88-7+2032 ™ \ •7 + 2032/ ~^ \20 X 88-7 + 20327 10X88-7+20327 ' \30X 88-7+2032 •H 40 10x88-7= 887 + 2032 X 10=1- 2919 & X =3*46523 ist W =-003426 =7*53477 6x88-7 = 532-2 + 2032- X 6 = 0*77815 2564-2 &X =3*40895 2ndW = •002340 '3-36920 40X88-7= 3548 +2032 X 40= 1-60206 5580 &X =3-74663 3rd W = -007169 3'85543 50x88-7= 4435 +2032 X 50 =1-69897 6467 & X =3-81070 = 3^88827 798-3 +2032- X 9 = 0-95424 5th W 20X88-7= 1774 +2032 X 20= 1*30103 6th W 3806 &X =3-58047 •005255 =7-72056 142 Method 3 (continued). 7thW = -003426 30X88*7= 2661 +2032 X 30=1-47712 9th W = '007169 4693 &x =3*67145 8th W = -006393 =7-80567 ist ='003426 X of i =o- 2nd = *oo2340 X of '04609 = 2*66361 3rd = '007 169 - 4th ='007732 i'33639 = X of P3 5th ='003180 o'6682O=X ofP 6th ='0052 5 5 7th ='003426 P2=2i''7o 8th =-006393 P = 4'-658 9th ='007 1 69 W= '0461 W =-046090 « =75 Wi= 34 75 39 53 46 30 57 a2==39 W2= 23 34 *3 72 77 32 53 04=46 W3= 72 W4= 77 W.= 3* 300 225 117 78 106 37i 3" 322 60 90 171 285 «e=57 W?= 34 Ws= 64 *55° 897 3816 3542 960 3021 09 = 52 9-^72 32 43 5^ 461 34 64 72 128 172 104 96 258 364 1088 3744 i55o 897 . 3816 3542 960 3021 1088 2752 0 / 3744 . •. Mean result = 31 49 Zero =45° J9 461)22370(48-5 1844 418 30 Mean Angle =238 30 393° 3688 2420 2305 143 3049, a Cassiopese. Computation of P. Method 1. Epoch. Sum. No. of Meas. o / 1858-572 32 48 6 •712 •821 I* 54 64 27 6 10 •857 64 13 10 •857 60 25 10 •876 56 9 10 •876 •876 50 43 63 o 10 10 •887 53 33 10 •887 53 o 10 •890 56 58 IO •890 63 2 10 12)10*001 651 12 4- 112 1858-833 5 49 4-120 0 i*5 49 Zero =45° 15 = Mean Position. Errors. e2. Errors. •A Errors. 6*. 132 17424 H5 21025 14 196 ii 3*4 961 159 25281 35 1225 16 256 10 100 30 900 9 8 1 i I 66 4356 ii 121 77 59*9 47 2209 22 484 21 441 21 441 38 1444 3* 1024 77 5929 56 3136 4i 1681 163 26569 28 784 H3 20449 89 79*i 17 289 33 1089 35 1225 55 3025 5 25 17 289 45 2025 4* 1764 7 49 39 1521 84 7056 21 441 26 676 85 7225 171 29241 97 9409 89 7921 63 3969 24 576 152 23104 54 2916 54 2916 54 2916 18 3*4 I2O 14400 "5 13225 201 40401 95 9025 61 37*i 75 5625 103 10609 153 23409 46 2116 78 6084 66 4356 97 9409 3* 1024 67 4489 119 14161 89 79*i 53 2809 64 4096 35 1225 6 36 56 3136 49 2401 61 37*i 41 1681 7* 5184 37 1369 *4 196 86 7396 '9 361 73 53*9 15 2*5 30 900 105 11025 36 1296 4 16 1681 81 6561 28 784 3* 1024 69 4761 106 11236 148 21904 5 75 5625 no I2IOO 97 9409 ii 121 101 1 020 1 9 81 37 1369 40 1600 2116 95 9025 73 53*9 i4i 17161 5* 2704 103 10609 65 4225 87 7569 acfi 267375 155633 250 '55633 267375 Se2= 630536 Log. of 112 =2-0492180 Log. of in =2-0453230 4-0945410 Log. of -454936=7-6579503 4-0945410 Constant 5-5634093 Log. of 630536 = 5^7997099 Constant = 5-5634093 1-3631192 0-6815596 4'-8o35 -0433 144 Method 2. o / Errors. C2 3*4 47 __ 3*4 46 20 4OO 3*3 48 3*3 50 J9 39 36l 1521 3*4 " 3*4 38 It 1369 256 3*5 " ii 121 3*3 57 3*4 54 44 30 1936 900 3*4 57 *7 7*9 3*4 33 3*3 57 30 6 900 36 . 30 900 12) 53 29 Mean =324 27 Sc» = 94*9 Log. of 9429 =3-97447 Log. 12 = 1*07918 Constant =3'53738 Log. ii = 1*04139 1*51185 2*12057 075593 Log. -4549 &c. = 7*65795 P2=32'*50 2*12057 P = 5/*7oi W= -0308 Constant =.32!!l! Method 3. 23792 = 8, 5/2=CS1 39974=82 80279 = 83 114116 = 84 i i3454=sfi 9/2=CS3 i9/2=CS4 29/2=CS6 123083 = 8,5 81960=87 \lff*=^\ 576658 Io5/2=Cx(S1-fS2-f&c.) Log. of 576658 = 57609183 Log. of -4549 &c. = 1-6579503 Log. of 105 5*4188686 = 2*0211893 = 3-3976793 145 Method 3 (continued). #!=I25 28 #o — 12 ? 2Q #! — # = 2I & ( J1-#)2= 44' "2 1A2 *» #o — 126 27 14-44- Jf. fi — 2C ell #t — 12 ? AO be. — #= o 8? #/! = 125 2O 84.1 #7=126 o # =125 49 See Method 1. S = 3953 Log. of 3953 =3-5969268 Log. of -4549 &c. = 1-6579503 3-2548771 Log. of 6 = rw— i =0-7781513 «2 = 299/73 =2-4767258 ioX29973-f2498-5 sM ^20x299-73+2498-5 -1-2498-5 X 6=077815 st W 4296-88 &\ =3-63315 = •001396 =3-14500 and W =-001396 10X299-73 = 2997-3 +2498-5 X 10= i- 5495-8 &X =3-74003 3rd W ='001820 =3'25997 20X299-73 = 5994-6 +2498-5 X 20= 1-30103 8493-1 &X =3-92907 4th W =-002355 =¥'37196 30X299-73 = 8991-9 +2498-5 X 30= 1-47712 11490-4 &X =4-06034 5th W =-002611 =3-41678 6th W =-002355 7th W ='002355 146 ist ='001396 2nd = -001396 3rd = -001820 4th =-002355 5th = '0026 1 1 6th ='002355 7th = -0023 55 W =-014288 Method 3 (continued). Xof i X of '014288 1-84503 = 0*92252 = P2= 69'-99 P = 8'*366 W= -01429 = Xof P 3=3 TTT o W. IS 24 26 ~ 2t 5= 24 •= 24 144 28 X 14= 392 29 X 14= 406 87X 18=1566 74 X 24=1776 40 X 26=1040 20 X 24= 480 60 X 24=1440 H4) 576 1340 1296 440 432 • . Mean result =125 49 Zero =450 15 Mean Angle = 324° 26' Summary of Results. Name of Star. Mean Posi- tion. No. of Mea- sures. Sum of e2 e2. /2- P2. P. W. Me- thod S 706 . 6r° K 60 271 77O / / 7A'88 / IC'QT 61 8 ^7*07 j y1 7'7 1 **7 IQ 61 A 1 17*7 10*85 S 1596 2 Com. Ber 2-18 78 ic6 3C2Q C2i JUJ 1 66-4.1 8-ic i r Early observations 278 36 2 T«A7 « 2,78 76 " 877 T'n 2I78'O 3^-5 »* c co'8c Z3 30 27*66 1043 o. AjO JU 0731 o j->y °i 108 3 Observations of *3° 3U 278 70 **5 yj/>"iy */ 12* £!7 J U3 3*c c go T 8 eo *" 88-7 4-66 A6 1059. *J« 3U 1 12 670 ^76 zu jz, 4 A-8o •t" T3 3*4 z/ 24.08* c 3-* 3U 7W 8*77 31 JA't- *u " ^yy / a^yo ^ uy yy 0 3/ 147 November 17, 1859. Sir BENJAMIN C. BRODIE, Bart., President, in the Chair. In accordance with the Statutes, the President gave notice of the ensuing Anniversary Meeting for the election of Council and Officers. Captain Douglas Galton, John Denis Macdonald, Esq., George Murray Humphry, Esq., and William Odling, Esq., were admitted into the Society. Mr. C. C. Babington, Sir Henry Holland, Mr. Thomas Webster, the Rev. R. Willis, arid Col. Yorke, having been nominated by the President, were elected Auditors of the Treasurer's Accounts on the part of the Society. The following communications were read : — I. " On the frequent occurrence of Vegetable Parasites in the Hard Structures of Animals." By Professor A. KOLLTKER, of Wurzburg. (See p. 95.) II. " Researches on the Phosphorus-Bases." — No. VI. Phosph- ammomum-Compounds." By A. W. HOFMANN, LL.D., F.R.S. (See p. 100.) III. " Notes of Researches on the Poly- Ammonias." — No. VI. New Derivatives of Phenylamine and Ethylamine. By A. W. HOFMANN, F.R.S. (See p. 104.) IV. "On the Behayiour of the Aldehydes with Acids." By A. GEUTHER, Esq., and R. CARTMELL, Esq. (For Abstract, see p. 108.) V. " On the Action of Acids on Glycol " (Second Notice). By Dr. MAXWELL SIMPSON. (See p. 114.) VI. "Experiments on some of the Various Circumstances in- fluencing Cutaneous Absorption." By AUGUSTUS WALLER, M.D.. F.R.S. (Seep. 122.) VOL. X. M 148 VII. " On the Application of the Calculus of Probabilities to the results of measures of the Position and Distance of Double Stars." By The LORD WROTTESLEY, V.P.R.S. (See p. 133.) VIII. " Report of Scientific Researches made during the late Arctic Voyage of the Yacht ' Fox/ in search of the Frank- lin Expedition/' By Captain M'CLINTOCK, R.N. Com- municated by General SABINE, R.A., Treas. & V.P.R.S. Received September 23, 1859. SIR, — I have the honour to acquaint you for the information of the President and Council of the Royal Society, that my voyage has happily terminated, and that our exertions have met with as great a measure of success as the most sanguine amongst us could expect. But as the general result of Lady Franklin's "Final Search" will doubtless be made public before this letter reaches you, my object is simply to acquaint you with the nature and extent of such observa- tions of scientific interest as we have been enabled to make. My last communication, dated 5th May, 1858, informed you of the unfortunate circumstances which led to our first Arctic winter being spent in an ice-drift out of Baffin's Bay. During the winter of 1858-59 we were frozen up in a secure anchorage in Brentford Bay, which I have named " Port Kennedy ;" it is in Latitude 72° 01' N. and Longitude 94° 15' W. Here a magnetic observatory was built, the instruments supplied to us set up, and hourly observations continued during the interval between autumn and spring travelling. Fortunately I was able to carry with me a 9 \ -inch dip-circle upon my journey to the Great Fish River this spring, and embraced every opportunity of making ob- servations with it, many of them in the immediate vicinity of the point of maximum inclination. Indeed it gives me much satisfaction to state that I believe our entire series of magnetical observations will be found complete — in as far as we were provided with the necessary instruments and favoured with the opportunities of using them. Meteorological records have been carefully kept throughout the voyage, and the "Weather Books" supplied by Admiral FitzRoy 149 filled up ; also, comparisons of temperatures shown by a black-bulb thermometer in the sun's rays, and by others suspended against black and white surfaces, with those of a thermometer in the shade, were frequently made during two years. Dr. Joseph Hooker having suggested that some observations should be made on the temperature of the soil at different depths, such were registered at short intervals throughout the winter and spring of 1858-59. Observations upon the amount of ozone present in the atmosphere were made during the winter and spring of 1857-58, and also for eleven months at Port Kennedy, 1858-59. Whenever opportunity offered, the polariscope, supplied at the instance of Professor Stokes, was applied to halos, &c., and the amount and plane of polarization noticed. The direction of the Aurora and its influence on an electroscope, together with the periods of maximum and minimum intensity of atmospheric electricity, were observed. The periods of maximum and minimum barometric pressure were recorded, as deduced from hourly and two-hourly observations. A series of experiments was made on the change produced in sea- water by congelation at different temperatures. Deep-sea temperatures and specific gravities were taken when opportunity offered ; also of the surface of the sea constantly. The great comet was seen at Port Kennedy, and a few angular measurements taken for determining its change of position, at in- tervals between 13th September and 8th October. Selections of native plants, from Port Kennedy and from Disco, have been brought home in Wardian cases, for the Royal Botanic Gardens at Kew. Considerable collections have also been made in the various branches of Natural History ; and Geological specimens from the lands visited have been brought home for scientific friends of the Expedition, who will speedily make public any interesting results : for these collections, and also for many of the observations made during the voyage, I am chiefly indebted to the Surgeon, David Walker, M.D. A series of Tidal observations was taken at Port Kennedy ; these will be discussed by the Rev. Professor Haughton, F.R.S., of Trinity College, Dublin. 150 Our geographical discoveries amount to nearly 800 miles of coast- line ; they are interesting not only in consequence of their extent and the important position they occupy, but also from the great difficulty of access, whether by sea or land, to this newly explored area. With the exception of a comparatively small and unimport- ant part of the shore of Victoria Land, the whole of the coasts of Arctic America are now accurately delineated, My sledge journey to the Magnetic Pole in February completed the discovery of the coastline of the American Continent. The in- sularity of Prince of Wales Land was ascertained, and the discovery of its coastline completed, by a sledge party under the direction of the Sailing-master, Captain Allen Young, as also the west coast of North Somerset between Bellot Strait and Four River Bay. Lieute- nant Hobson, R.N. and his sledge party completed the discovery of the west coast of King William's Island, picking up the Franklin records ; whilst with my own I explored its eastern and southern shores, returning northward by its west shore from the Great Fish River. Repeated attempts were made last year before the close of the navigable season, to reach open water visible in the broad channel westward of North Somerset ; but a narrow barrier of ice across the western outlet of Bellot Strait, and there hemmed in so firmly by numerous islets as to continue unbroken throughout the autumn gales, foiled my sanguine hope of carrying the * Fox,' according to my original plan, southward to the Great Fish River, passing east of King William's Island and from thence to some wintering position upon Victoria Land. From a very careful scrutiny of the ice during my journeys over it in February, March, April, May, and June, it was evident that in this western sea it was all broken up ; whilst east- ward and southward of King William's Island there was hardly any ice last autumn ; and therefore in all probability we saw, in that barrier of ice some three or four miles wide, the only obstruction to our complete success. The wide channel between Prince of Wales Land and Victoria Land, upon which I have conferred the name of Lady Franklin, admits a vast and continuous stream of very heavy ocean-formed ice from the north-west, which presses upon the western face of King William's Island and chokes up Victoria Strait. 151 I cannot divest myself of the belief that had Sir John Franklin been aware of the existence of a channel eastward of King William's Land (so named until 1854), and sheltered from this impenetrable ice-stream, his ships would safely and speedily have passed through it in 1846, and from thence with comparative ease to Behring Strait. Having enumerated the different subjects which have engaged the attention of the officers and myself and have employed much of our time, it only remains for me to express a hope that these will be found to be in some measure a justification of any moderate expecta- tions which the President and Council of the Royal Society may have formed at the time of my departure from England in 1857, or at least to afford proof that my desire to be rendered useful in the ad- vancement of science has in no degree abated since then. I am, Sir, your obedient Servant, , F. L. MCCLINTOCK, To the Secretary of the Royal Society. Captain R.N. November 24, 1859. Major-General SABINE, R.A., Treasurer and V.P., in the Chair. In accordance with the Statutes, notice was given from the Chair of the ensuing Anniversary Meeting, and the list of Officers and Council proposed for election was read as follows : — President. — Sir Benjamin Collins Brodie, Bart., D.C.L. Treasurer. — Major-General Edward Sabine, R.A., D.C.L. . J William Sharpey, M.D. "t George Gabriel Stokes, Esq., M.A., D.C.L. Foreign Secretary. — William Hallows Miller, Esq., M.A. Other Members of the Council. — C. CardaleBabington, Esq., M.A. j Rear-Admiral Sir George Back, D.C.L. ; Rev. John Barlow, M.A. ; Thomas Bell, Esq. ; Arthur Cayley, Esq. ; William Farr, M.D., D.C.L ; Sir H. Holland, Bart., M.D., D.C.L. ; Thomas Henry Huxley, Esq. ; Sir Roderick I. Murchison, M.A., D.C.L. ; Thomas 152 Webster, Esq., M.A. ; Rev. William Whewell, D.D. ; Alex. William Williamson, Ph.D. ; Rev. Robert Willis, M.A. ; Sir William Page Wood, D.C.L. ; The Lord Wrottesley, M.A. ; Colonel Philip Yorke. Thomas Watson, M.D., Frederick Grace Calvert, Esq., John Penn, Esq., and Lieut.-Col. William Yolland, R.E., were admitted into the Society. The following communications were read : — I. " On Recent Theories and Experiments regarding Ice at or near its Melting-point." By Professor JAMES THOMSON, Queen's College, Belfast. Communicated by Professor WILLIAM THOMSON, F.R.S. Received September 9, 1859. My object in the following paper is to discuss briefly the bearings of some of the leading theories of the plasticity and other properties of ice at or near its melting-point, on speculations on the same sub- ject advanced by myself*, and, especially, to offer an explanation of an experiment made by Professor James D. Forbes, which to him and others has seemed to militate against the theory proposed by me, but which, in reality, I believe to be in perfect accordance with that theory. In the year 1850, Mr. Faraday f invited attention, in a scientific point of view, to the fact that two pieces of moist ice, when placed in contact, will unite together, even when the surrounding temperature is such as to keep them in a thawing state. He attributed this pheno- menon to a property which he supposed ice to possess, of tending to solidify water in contact with it, and of tending more strongly to so- lidify a film or a particle of water when the water has ice in contact with it on both sides than when it has ice on only one side. In January 1857, Dr. Tyndall, in a paper (by himself and Mr. Huxley) read before the Royal Society and in a lecture delivered at the Royal Institution, adopted this fact as the basis of a theory by which he proposed to explain the viscosity or plasticity of ice, or its capability of undergoing change of form, which was pre- * Proceedings of Royal Society, May 1857. Also British Association Proceed- ings, Dublin Meeting, 1857. Also Proceedings of Belfast Literary and Philoso- phical Society, December 2, 1857. t Lecture by Mr. Faraday at the Royal Institution, June 7, 1850 ; and Report of that Lecture, Athenaeum, 1850, p. 640. 153 viously known to be the quality in glaciers in virtue of which their motion down their valleys is produced by gravitation. Designating Mr. Faraday's fact under the term " regelation," Dr. Tyndall de- scribed the capability of glacier ice to undergo changes of form, as being not true viscosity, but as being the result of vast numbers of successively occurring minute fractures, changes of position of the fractured parts, and regelations of those parts in their new positions. The terms fracture and regelation then came to be the brief expres- sion of his idea of the plasticity of ice. He appears to have been led to deny the applicability of the term viscosity through the idea that the motion occurs by starts due to the sudden fractures of parts in themselves not viscous or plastic. The crackling, he pointed out might, according to circumstances, be made up of separate starts distinctly sensible to the ear and to the touch, or might be so slight and so rapidly repeated as to melt almost into a musical tone. He referred to slight irregular variations in the bending motion of the line marked by a row of pins on a glacier by Prof. Forbes, as being an indication of the absence of any quality that could properly be called viscosity, and of the occurrence of successive fractures and sudden motions in a material not truly viscous or plastic. I can only understand his statements on this subject by supposing that he con- ceived the material between the cracks to be rigid, or permanent in form, when existing under strains within the limit of its strength, or when strained less than to the point of fracture. This theory appeared to me to be wrong* ; and I then published, * While the offering of my own theory as a substitute for Professor Tyndall's views seems the best argument I can adduce against them, still I would point to one special objection to his theory. No matter how fragile, and no matter how much fractured a material may be, yet if its separate fractured parts be not possessed of some property of internal mobility, I cannot see how a succession of fractures is to be perpetuated. A heap of sand or broken glass will either continue standing, or will go down with sudden falls or slips, after which a position of repose will be attained ; and I cannot see how the addition of a principle of reunion could tend to reiterate the fractures after such position of repose has been attained. When these ideas are considered in connexion with the fact that while ice is capable of standing, without immediate fall, as the side of a precipitous crevasse, or of lying without instantaneous slipping on a steeply sloping part of a valley, it can also glide along, with its surface nearly level, or very slightly inclined, I think the improbability of the motion arising from a succession of fractures of a substance having its separate parts devoid of internal mobility will become very apparent. If, on the other hand, any quality of internal mobility be allowed in the fragments between the cracks, a certain degree at least of plasticity or viscosity is assumed, 154 in a paper communicated to the Royal Society, a theory which had occurred to me mainly in or about the year 1848, or perhaps 1850 ; but which, up till the date of the paper referred to, had only been described to a few friends verbally. That theory of mine may be sketched in outline as follows : — If to a mass of ice at its melting- point, pressures tending to change its form be applied, there will be a continual succession of pressures applied to particular parts — liquefaction occurring in those parts through the lowering of the melting-point by pressure — evolution of the cold by which the so melted portions had been held in the frozen state — dispersion of the water so produced in such directions as will afford relief to the pressure — and recongelation, by the cold previously evolved, of the water on its being relieved from this pressure: and the cycle of operations will then begin again ; for the parts re-congealed, after having been melted, must in their turn, through the yielding of other parts, receive pressures from the applied forces, thereby to be again liquefied and to proceed through successive operations as before. Professor Tyndall, in papers and lectures subsequent to the publi- cation of this theory, appears to adopt it to some extent, and to endea- vour to make its principles cooperate with the views he had previously founded on Mr. Faraday's fact of so called " regelation"*. Professor James D. Forbes adopts Person's view, that the dissolu- tion of ice is a gradual, not a sudden process, and so far resembles the tardy liquefaction of fatty bodies or of the metals, which in melting pass through intermediate stages of softness or viscosity. He thinks that ice must essentially be colder than water in contact with in order to explain the observed plasticity or viscosity. That fractures — both large and exceedingly small — both large at rare intervals, and small, momentarily repeated — do, under various circumstances, arise in the plastic yielding of masses of ice, is, of course, an undoubted fact : but it is one which I regard not as the cause, but as a consequence, of the plastic yielding of the mass in the manner supposed in my own theory. It yields by its plasticity in some parts until other parts are overstrained and snap asunder, or perhaps also sometimes slide suddenly past one another. * I suppose the term regelation has been given by Prof. Tyndall as denoting the second, or mending stage in his theory of "fracture and regelation" Congela- tion would seem to me the more proper word to use after fracture, as regelation implies previous melting. If my theory of melting by pressure and freezing again on relief of pressure be admitted, then the term regelation will come to be quite suitable for a part of the process of the union of the two pieces of ice, though not for the whole, which then ought to be designated as the process of melting and rcgelation. 155 it ; that between the ice and the water there is a film varying in local temperature from side to side, which may be called plastic ice, or viscid water ; and that through this film heat must be constantly passing from the water to the ice, and the ice must be wasting away, though the water be what is called ice-cold. There is a manifest difficulty in conceiving the possibility of the state of things here described : and I cannot help thinking that Professor Forbes has been himself in some degree sensible of the difficulty ; for in a note of later date by a few months than the paper itself, he amends the expression of his idea by a statement to the effect that if a small quantity of water be enclosed in a cavity in ice, it will undergo a gradual " revelation ; " that is, that the ice will in this case be gradually increased instead of wasted. In reference to the first case, I would ask, — What becomes of the cold of the ice, supposing there to be no communication with external objects by which heat might be added to or taken from the water and ice jointly considered ? Does it go into the water and produce viscidity beyond the limit of the assumed thin film of viscid water at the sur- face of the ice ? Precisely a corresponding question may be put re- latively to the second case — that of the large quantity of ice enclosing a small quantity of water in which the reverse process is assumed to occur. Next, let an intermediate case be considered — that of a me- dium quantity of water in contact with a medium quantity of ice, and in which no heat, nor cold, practically speaking, is communicated to the water or the ice from surrounding objects. This, it is to be ob- served, is no mere theoretical case, but a perfectly feasible one. The result, evidently, if the previously described theories be correct, ought to be that the mixture of ice and water ought to pass into the state of uniform viscidity. Prof. Forbes' s own words distinctly deny the permanence of the water and ice in contact in their two separate states, for he says, " bodies of different temperatures cannot continue so without interaction. The water must give off heat to the ice, but it spends it in an insignificant thaw at the surface, which therefore wastes even though the water be what is called ice-cold.'9 Now the conclusion arrived it, namely, that a quantity of viscid water could be produced in the manner described, is, I am satisfied, quite contrary to all experience. No person has ever, by any peculiar application of heat to, or withdrawal of heat from, a quantity of water, rendered it 156 visibly and tangibly viscid. We even know that water may be cooled much below the ordinary freezing-point and yet remain fluid. Professor Forbes regards Mr. Faraday's fact of regelation as being one which receives its proper explanation through his theory described above ; and, in confirmation of the supposition that ice has a tendency to solidify a film of water in contact with it, and in opposition to the theory given by me, that the regelation is a consequence of the low- ering of the melting-point in parts pressed together, he adduces an experiment made by himself, which I admit presents a strong appear- ance of proving the influence of the ice in solidifying the water, to be not essentially dependent on pressure. This experiment, however, I propose to discuss and explain in the concluding part of the present paper. Professor Forbes accepts my theory of the plasticity of ice as being so far correct that it points to some of the causes which may reason- ably be considered, under peculiar circumstances, to impart to a glacier a portion of its plasticity. In the rapid alternations of pres- sure which take place in the moulding of ice under the Bramah's press, it cannot, he thinks, be doubted that the opinions of myself and my brother Professor Wm. Thomson are verified*. Mr. Faraday, in his recently published ' Researches in Chemistry and Physics/ still adheres to his original mode of accounting for the phenomenon he had observed, and for which he now adopts the name "regelation;" or, at least, while alluding to the views of Prof. Forbes as possibly being admissible as correct, and to the explanation offered by myself as being probably true in principle, and possibly having a correct bearing on the phenomena of regelation, he consi- ders that the principle originally assumed by himself may after all be the sole cause of the effect. The principle he has in view, he then states as being, when more distinctly expressed, the following : — " In all uniform bodies possessing cohesion, i. e. being either in the liquid or the solid state, particles which are surrounded by other particles having the like state with themselves tend to preserve that state, even though subject to variations of temperature, either of elevation or de- pression, which, if the particles were not so surrounded, would cause * Forbes ' On the Recent Progress and Present Aspect of the Theory of Glaciers,' p. 12 (being Introduction to a volume of Occasional Papers on the Theory of Glaciers), February 1859. 157 them instantly to change their condition." Referring to water in illustration, he says that it may be cooled many degrees below 32° Fahr., and still retain its liquid state ; yet that if a piece of the same chemical substance — ice — at a higher temperature be introduced, the cold water freezes and becomes warm. He points out that it is cer- tainly not the change of temperature which causes the freezing ; for the ice introduced is warmer than the water ; and he says he assumes that it is the difference in the condition of cohesion existing on the different sides of the changing particles which sets them free and causes the change. Exemplifying, in another direction, the principle he is propounding, he refers to the fact that water may be exalted to the temperature of 270° Fahr., at the ordinary pressure of the atmo- sphere, and yet remain water; but that the introduction of the smallest particle of air or steam will cause it to explode, and at the same time to fall in temperature. He further alludes to numerous other substances — such as acetic acid, sulphur, phosphorus, alcohol, sulphuric acid, ether, and camphine — which manifest like phenomena at their freezing- or boiling-points, to those referred to as occurring with the substance of water, ice, and steam ; and he adverts to the ob- served fact that the contact of extraneous substances with the parti- cles of a fluid usually sets these particles free to change their state, in consequence, he says, of the cohesion between them and the fluid being imperfect ; and he instances that glass will permit water to boil in contact with it at 212° Fahr., or by preparation can be made so that water will remain in contact with it at 270° Fahr. without going off into steam ; also that glass can be prepared so that water will remain in contact with it at 22° Fahr. without solidification, but that an ordinary piece of glass will set the water off at once to freeze. He afterwards comes to a point in his reasoning which he admits may be considered as an assumption. It is " that many particles in a given state exert a greater sum of their peculiar cohesive force upon a given particle of the like substance in another state than few can do ; and that as a consequence a water particle with ice on one side, and water on the other, is not so apt to become solid as with ice on both sides ; also that a particle of ice at the surface of a mass [of ice] in water is not so apt to remain ice as when, being within the mass there is ice on all sides, temperature remaining the same." 158 This supposition evidently contains two very distinct hypotheses. The former, which has to do with ice and water present together, I certainly do regard as an assumption, unsupported hy any of the phenomena which Mr. Faraday has adduced. The other, which has to do with a particle of ice in the middle of continuous ice, and which assumes that it will not so readily change to water, as another particle of ice in contact with water, I think is to be accepted as pro- bably true. I think the general bearing of all the phenomena he has adduced is to show that the particles of a substance when existing all in one state only, and in continuous contact with one another, or in contact only under special circumstances with other substances, ex- perience a difficulty of making a beginning of their change of state, whether from liquid to solid, or from liquid to gaseous, or probably also from solid to liquid : but I do not think anything has been ad- duced showing a like difficulty as to their undergoing a change of state, when the substance is present in the two states already, or when a beginning of the change has already been made. I think that when water and ice are present together, their freedom to change their state on the slightest addition or abstraction of heat, or the slightest change of pressure, is perfect. I therefore cannot admit the validity of Mr. Faraday's mode of accounting for the phenomena of regelation. Thus the fact of regelation which Prof. Tyndall has taken as the basis of his theory for explaining the plasticity of ice, does in my opinion as much require explanation as does the plasticity of ice which it is applied to explain. The two observed phenomena, namely the tendency of the separate pieces of ice to unite when in contact, and the plasticity of ice, are indeed, as I believe, cognate results of a com- mon cause. They do not explain one another. They both require explanation ; and that explanation, I consider, is the same for both, and is given by the theory I have myself offered . I now proceed to discuss the experiment by Prof. Forbes, already referred to as having been adduced in opposition to my theory. He states that mere contact without pressure is sufficient to produce the union of two pieces of moist ice * ; and then states, as follows, his experiment by which he supposes that this is proved : — " Two slabs * " On some Properties of Ice near its Melting-Point," by Prof. Forbes, Pro- ceedings Royal Soc. Edin., April 1858. 159 of ice, having their corresponding surfaces ground tolerably flat, were suspended in an inhabited room upon a horizontal glass rod passing through two holes in the plates of ice, so that the plane of the plates was vertical. Contact of the even surfaces was obtained by means of two very weak pieces of watch spring. In an hour and a half the cohesion was so complete, that, when violently broken in pieces, many portions of the plates (which had each a surface of twenty or more square inches) continued united. In fact it appeared as complete as in another experiment where similar surfaces were pressed together by weights." He concludes that the effect of pressure in assisting ' regelation' is principally or solely due to the larger surfaces of con- tact obtained by the moulding of the surfaces to one another. I have myself repeated this experiment, and have found the re- sults just described to be fully verified. It was not even necessary to apply the weak pieces of watch-spring, as I found that the pieces of ice, on being merely suspended on the glass rod in contact, would unite themselves strongly in a few hours. Now this fact I explain by the capillary forces of the film of interposed water as follows: — Firstly, the film of water between the two slabs — being held up against gravity by the capillary tension, or contractile force, of its free upper surface, and being distended besides, against the atmospheric pressure, by the same contractile force of its free surface round its whole perimeter, except for a very small space at bottom, from which water trickles away, or is on the point of trickling away — exists under a pressure which, though increasing from above downwards, is everywhere, ex- cept at that little space at bottom, less than the atmospheric pres- sure. Hence the two slabs are urged towards one another by the ex- cess of the external atmospheric pressure above the internal water pressure, and are thus pressed against one another at their places of contact by a force quite notable in its amount. If, for instance, be- tween the two slabs there be a film of water of such size and form as might be represented by a film one inch square, with its upper and lower edges horizontal, and with water trickling from its lower edge, it is easy to show that the slabs will be pressed together by a force equal to the weight of half a cubic inch of water. But so small a film as this would form itself even if the two surfaces of the ice were only very imperfectly fitted to one another. If, again, by better fitting, a film be produced of such size and form as may be represented by a 160 square film with its sides 4 inches each, the slabs will be urged toge- ther by a force equal to the weight of half a cube of water, of which the side is 4 inches ; that is, the weight of 32 cubic inches of water or 1*15 pound, which is a very considerable force. Secondly, the film of water existing, as it does, under less than atmospheric pressure, has its freezing-point raised in virtue of the reduced pressure ; and it would therefore freeze even at the temperature of the surrounding ice, namely the freezing-point for atmospheric pressure. Much more will it freeze in virtue of the cold given out in the melting by pressure of the ice at the points of contact, where, from the first two causes named above, the two slabs are urged against one another. The freezing of ice to flannel or to a worsted glove on a warm hand is, I consider, to be attributed partly to capillary attraction acting in similar ways to those just described ; but in many of the ob- served cases of this phenomenon there will also be direct pressures from the hand, or from the weight of the ice, or from other like causes, which will increase the rapidity of the moulding of the ice to the fibres of the wool. II. "On Spontaneous Evaporation/' By BENJAMIN Guy BABINGTON, M.D., F.R.S. &c. Received June 7, 1859. (For Abstract, see p. 127.) November 30, 1859. ANNIVERSARY MEETING. Sir BENJAMIN C. BRODIE, Bart., President, in the Chair. Colonel Yorke reported, on the part of the Auditors of the Trea- surer's Accounts, that the total receipts during the past year, in- cluding ^63466 3s. 2d. received from the Stevenson bequest, amounted to ^670 16 Os. 5d. ; and the total expenditure, including ^2700 invested in the Funds, amounted to ^66596 Os. 5d., leaving a balance in the Treasurer's hands amounting to £420. The thanks of the Society were voted to the Treasurer and Auditors. The Secretary read the following lists : — 161 Fellows deceased since Henry Alexander, Esq. Richard Bright, M.D. Frederick William, Marquis of Bristol. William John Broderip, Esq. Sir Arthur de Capell Brooke, Bt. Isambard Kingdom Brunei, Esq. Thomas Cook, Esq. William Nairn Forbes, Esq. Baron De Goldsmid. Sir Thomas Grant, K.C.B. Thomas Philip, Earl De Grey, K.G. Thos., Earl of Haddington, K.P. the last Anniversary. Henry Hallam, Esq., M.A. William Richard Hamilton, Esq. Arthur Henfrey, Esq. Thomas Hetherington Henry,Esq. Thomas Horsfield, M.D. Manuel John John son, Esq., M.A,* Bishop Maltby, D.D. Rev. Charles Mayo, B.D. George Moore, Esq. Frederick John, Earl of Ripon. Sir George T. Staunton, Bart. Robert Stephenson, Esq., D.C.L. Rev. Henry Walter, B.D. John Welsh, Esq. On the Foreign List. Gustav Lejeune Dirichlet. Baron Alexander von Humboldt. Carl Ritter. Fellows elected since Samuel Husbands Beckles, Esq. Frederick Grace Calvert, Esq. Henry J. Carter, Esq. Capt. Douglas Galton, R.E. William Bird Herapath, M.D. George Murray Humphry, Esq. Thomas Sterry Hunt, Esq. Archibald Campbell Tait, Lord Bishop of London. John Denis Macdonald, Esq. the last Anniversary. William Odling, Esq. Robert Patterson, Esq. John Penn, Esq. Robert Bickersteth, Lord Bishop of Ripon. Sir Robert Schomburgk. Thpmas Watson, M.D. Bennet Woodcroft, Esq. Lieut.-Col. William Yolland, R.E. The President then addressed the Society as follows : — GENTLEMEN, IN an address lately delivered at a Meeting of the Society for the Promotion of Social Science, a noble Lord, a Fellow of this Society, 162 called the attention of his hearers to the advantages which the world in general had derived from the cultivation of the physical sciences. No one indeed can be better qualified to give an opinion on this subject than the distinguished individual to whom I have alluded. His first communication to the Royal Society was in the year 1796, and was published in the 'Philosophical Transactions' for that year. From that time to the present day he has, without any intermission, laboured for the advancement of all kinds of knowledge, and so he still continues to labour with all the determination and energy and intellectual vigour of youth ; and I may confidently affirm that little has been done worthy of note during this interval of sixty-four years which has escaped his acute observation. The influence, however, which the physical sciences have had in adding to the conveniences and comforts, and advancing the material pros- perity of mankind is too obvious to escape the notice of a much less close observer than Lord Brougham. If our houses and our cities are better and more economically lighted ; if our population is better and more cheaply clothed ; if our fields are more productive ; if we travel by steam and communicate with those who are hundreds of miles distant from us by the telegraph ; if a brighter light shines in our light-houses to guide the mariner at night ; these and a thou- sand of things besides are but the result of the application by prac- tical men, of the discoveries made in the physical sciences, to prac- tical purposes. To the same cause may be attributed much of the political greatness of the British nation. The British flag floats in every sea ; our colonies are established in every region of the earth ; we contemplate in them with a reasonable pride the germs of future nations, which, when our fortune may possibly be changed, will speak the same language with ourselves, inheriting our literature, our political institutions, and not only our religion but our religious freedom, inheriting also our knowledge, and adding knowledge to it ; but none of this could have been, if it were not that the astro- nomer had instructed the sailor how, with nothing but the heavens above him and the waters on every side, he may find his exact posi- tion on the surface of the globe. But it would be a grave mistake to suppose that such as those which I have now enumerated are the only advantages which have been derived from the cultivation of the physical sciences. To know 163 their full extent, we must take into the account not only the direct but also the indirect results to which it has led ; and I trust that I may be excused if, on the occasion of the present anniversary, I oc- cupy some portion of your time, not by an elaborate discussion of the subject, but by offering to you some suggestions as to the other ways in which inquiries such as those in which you are yourselves engaged have already affected, and may be expected still more to affect hereafter, the habits, the modes of thought, the fortunes and moral condition of mankind. It is not our business to depreciate that form of civilization which existed in times long since past, and especially of that remarkable people who during some centuries before and after the Christian sera were distinguished for their still unrivalled excellence in art, their noble literature, when Aristotle sat at the feet of his master Plato, when students in search of intellectual improvement from all parts of Greece resorted to the Lyceum of Athens, when from opposite quarters of the Mediterranean Sea the Greek colonies of Alexandria and Syracuse supplied a list of mathematicians and poets to add lustre to their parent state. Neither let us forget what we owe to another people, whose civilization is to be measured, not by their wealth and luxury, their ambition and their conquests, but by those monuments of art which still draw visitors to Rome, their historians, moral philosophers, and poets. But, great as are the obligations which we owe to these nations of antiquity, it cannot be denied that the civilization which exists among us at the present time is of a higher order than that which existed formerly : and it is not difficult to show that it is to the greater extension of a knowledge of natural phenomena, and the laws which govern them, that this improvement is mainly to be attributed. Knowledge and wisdom are indeed not identical ; and every man's experience must have taught him that there may be much know- ledge with little wisdom, and much wisdom with little knowledge. But with imperfect knowledge it is difficult or impossible to arrive at right conclusions. Many of the vices, many of the miseries, many of the follies and absurdities by which human society has been infested and disgraced may be traced to a want of knowledge. It was from a want of knowledge that Roger Bacon was persecuted by the Franciscan monks, and Galileo by the Inquisition ; that Servetus was VOL. X. N 164 burned by Calvin ; while others would have burned Calvin in his turn if they had had the opportunity of doing so. So it was that juries were found to convict and judges to condemn poor igno- rant women as witches ; that within the last two centuries well- educated men believed that they might read their destiny in the stars ; and that as lately as the year 1638, on the occasion of the birth of Louis XIV., Richelieu compelled the dungeons of the Inquisition to give up the astrologer Campanella, in order that he might cast the horoscope of the future king ; and so it is that at the present day grown-up ladies and gentlemen occupy themselves with the humbler and less romantic mysteries of turning and rapping tables. Cooperating with a purer religious faith, the advancement of knowledge has humanized our institutions. It has banished slavery ; it has caused our laws to be more merciful, and the ad- ministration of them more just ; it has promoted religious and po- litical freedom, and, with one or two miserable exceptions, it has rendered even despotic governments more attentive to the claims and wishes of their subjects. If sanitary and other improvements (these being the results of greater knowledge) have added to the average length of human life, be it observed that this fact includes another fact, namely, that they have added to human happiness ; for true it is that the causes which tend to the shortening of life are, with few exceptions, such as produce either physical pain or moral suffering. The investigation of the physical sciences is especially favourable to the training of some of the more important faculties of the mind, so that we may well anticipate much ultimate advantage from the movement which is already begun, having for its object, not to supersede the study of ancient languages and ancient literature (which at the present time, in addition to mathematics, are supposed to form the staple of a first-rate education), but to add an elementary knowledge of the principal physical sciences to the list. The in- cluding of some of these at least in the instruction of early life will operate beneficially in various ways. The first step in all physical investigations, even in those which admit of the application of mathe- matical reasoning and the deductive method afterwards, is the obser- vation of natural phenomena ; and the smallest error in such obser- vation in the beginning is sufficient to vitiate the whole investigation 165 afterwards. The necessity of strict and minute observation, then, is the first thing which the student of the physical sciences has to learn ; and it is easy to see with what great advantage the habit thus acquired may be carried into everything else afterwards. Slovenly habits of observation are indeed the source of a large proportion of the evils which mankind bring upon themselves— of blunders in private life by which an individual causes the ruin of himself and his wife and children, of blunders in statesmanship which bring cala- mities on nations. It is to these, moreover, that impostors and fanatics of all kinds and in all ages have been indebted for their influence and success. It would be easy to show how in various other ways the study of the physical sciences cannot fail to be a useful training for the mind. Very much indeed might be said on this subject; but to enter fully into it would not only occupy too much of your time, but would involve us in a metaphysical discussion unsuited to the present occasion. There are, nevertheless, two or three points to which I shall venture, however briefly, to allude. Investigations of this kind, more than almost any other, impress the mind with the necessity of looking carefully at both sides of a question, and strictly comparing the evidence on one side with that on the other ; and in this manner they help to correct and improve the judgment. As in every such investigation classification is an important and indeed a necessary element, another effect is that of promoting and strengthening the best kind of memory — a memory founded on some actual relation of objects to each other, and not on mere apparent resemblance and juxtaposition. Lastly, physical investigations more than anything besides help to teach us the actual value and the right use of the imagination, — of that wondrous faculty which, left to ramble uncontrolled, leads us astray into a wilderness of perplexities and errors, a land of mists and shadows ; but which, properly restrained by experience and reflection, becomes the noblest attribute of man — the source of the poetic genius, the instrument of discovery in science, without the aid of which Newton would never have invented fluxions, nor Davy have decomposed the earths and alkalies, nor would Columbus have found another continent beyond the Atlantic Ocean. In the pursuit of the physical sciences, the imagination supplies 166 the hypothesis which bridges over the gulf that separates the known from the unknown. It may be only a phantom ; it may prove to be a reality. But as these sciences relate to matters of fact which, if not directly, may be made indirectly cognizable by the external senses, they afford us peculiar facilities, far beyond what exist in other departments of knowledge, of testing the accuracy of the views which the imagination has suggested, so that we may at once determine when it has been too excursive, and, if it has been so, call it back to its right place. There may be instances of mere accidental discovery ; but, setting these aside, the great advances made in the inductive sciences are, for the most part, preceded by a more or less probable hypothesis. The imagination, having some small light to guide it, goes first. Further observation, experiment, and reason follow. Thus, for example, it had been long suspected that there is some sort of relation between electricity and magnetism. Much thinking on the subject had strengthened this suspicion in the mind of Oersted. Still it was but a hypothesis, and might even now have been re- garded by many as no better than a dream, if it had not been that in the year 1820 the Danish philosopher devised the experiments which demonstrated the law of reciprocity between an electric current and the magnet, and the identity of the two forces. As an instance of an opposite kind, I may refer to the doctrine of phlogiston as pro- pounded by Stahl. While the art of chemical experiment was im- perfectly understood, that doctrine was very generally received as affording a true explanation of the phenomena of combustion. But no sooner had Lavoisier and his friends introduced a more accurate mode of experiment by weight and measure, than it was proved to have no foundation in reality, and consigned to the same place in the history of science with epicycles and vortices and animal spirits. But the effect of some kind of instruction in the physical sciences being recognized as an essential part of a liberal education, may be contemplated under another point of view. Except in the case of particular professions or occupations, a profound knowledge of these subjects is not required ; but there is no situation in life in which some knowledge of them may not be turned to a good account. Is there any country gentleman or farmer who might not derive advantage from knowing something of vegetable physiology and chemistry? — would not a knowledge of scientific botany make a man a better 167 gardener ? — is there any county magistrate, or mayor, or alderman of a borough, to whom it would not be useful to know something of the principles on which what are called sanitary measures are to be conducted ? — and is there anyone in any situation in life to whom it would not be a benefit to know something of animal physiology, of the functions of his own body, and of the influence which his bodily condition exercises over those moral and intellectual faculties by which he is distinguished from the rest of the animal creation ? If it did not teach him how to cure disease, it might be useful for him to know how far disease may cure itself, and what are the limits of Nature in this respect ? To man, looking at him as an individual, there is no art so important as that of understanding and managing himself, — an art so simply and well expressed by the two significant words rVwflt aeavTov, which were inscribed over the heathen oracle of Delphi. To correct bad habits when once acquired is no very easy task ; a strong sense and a strong will, such as only a limited number of persons possess, are necessary for that purpose. But it would go far towards preventing the acquirement of such habits, if young persons, during the period of their education, were made to understand the ill consequences to which they must inevitably lead, and how, eventually, the body must suffer and the mind be stupefied and degraded, not by the reasonable indulgence, but by the abuse of the animal instincts. In the Introduction to his ' Inquiry into the Human Understand- ing,' David Hume, having referred to the remarkable progress which had been lately made in a knowledge of astronomy and other physical sciences, has suggested that " the same method of inquiry, which has been applied with so great advantage in these sciences, might also be applied with advantage to those other sciences which have for their object the mental power and economy." I call your attention to this remark, because it brings me to the consideration of another subject, namely, the influence which the pursuit of the physical sciences, conducted as it has been more or less since the days of Galileo and Kepler, has exercised over other studies, and in the advancement of other kinds of knowledge. It needs no argument to prove, for it must be sufficiently plain to everyone, that other sciences as well as the physical have at the present time a very dif- ferent character from that which they had formerly. It was probably 168 from the operation of v.arious causes (a principal one, however, being the too exclusive and undue importance attached to the Aristotelian logic in the schools), that some centuries had elapsed since the revival of learning before the inductive method (which, by the way, is nothing more than the logic which we all make use of instinctively in the ordinary concerns of life) became generally applied to the in- vestigation of the phenomena and laws of the material universe. But a still further time elapsed, even after the publication of Lord Bacon's views on the subject, before other sciences began to partake of this movement ; and when they did so, it seems not possible to doubt that it was the result of the impulse which the rapid growth of the physical sciences had communicated to them. That such was the opinion of David Hume as to the influence thus exercised on one class of inquiries in which he was himself engaged, I have already shown. But long before Hume wrote, the same impression had existed on the mind of Locke, as will be suffi- ciently obvious to anyone on reading the Introductory Chapter of his 'Essay on the Human Understanding/ In fact Locke had originally directed his attention to Natural Philosophy and Medicine ; and his researches in Moral and Intellectual Philosophy were engrafted on his earlier studies. So in the case of Dr. Berkeley : his treatise on * Vision ' contains the essential part of those doctrines which he after- wards published in his * Treatise on the Principles of Human Know- ledge ; ' and it is easy to see how, step by step, these gradually arose out of his former studies of Natural Philosophy. I make no reference to the modern German school of metaphysicians, and indeed am quite incompetent to do so. Neither do I refer to another order of meta- physicians, one of whom informs us how ideas and emotions and volitions are produced by big and little vibrations of the molecules of the nervous system ; while another undertakes to explain " the action of material ideas in the mechanical machines of the brain." But with regard to the more eminent of our English writers on these subjects, and what has been called the Scotch school of metaphysicians, including Reid, Adam Smith, Dugald Stewart, and Brown, it may be truly asserted that the advantage which they have had over the dreamy metaphysicians of former times is to be attributed to their having in their mode of inquiry followed the example which had been set them in the study of the physical sciences. 169 I must not exhaust your patience by going on to explore so wide a field as that on which I have just entered. The subject is one to which justice cannot be done without a much more ample discussion than would be convenient on an occasion like the present. All that I shall say besides may be comprised in a very few words. In composing his ' Essays ' on what is now called Political Economy, we may presume that David Hume's mind was influenced by the same considerations as when he composed those other Essays to which I have alluded ; and it is not too much to say that these researches of Hume's may be regarded as having, more than anything besides, contributed to lay the foundation of that vast science which has been since developed through the labours of Adam Smith and Homer, and of others who are still alive among us. At the same time, in giving this credit to Hume, we must not over- look what is due to one of our own body, and an original Fellow of the Royal Society. Sir William Petty contributed several papers to the * Philosophical Transactions/ In an early part of his life he had been engaged in giving lectures on Anatomy and on Chemistry at Oxford ; and his mind having been thus prepared he entered on the con- sideration of other subjects, such as taxation and trade as affecting the material prosperity of nations, and social statistics. His ' Discourse on Political Arithmetic ' seems to have been the last result of his labours, it having been first published after his death, by his son, Lord Shelburne. In his Preface to this Discourse he thus expresses himself (and I quote the passage because it will serve to show how in these later investigations his mind was influenced by those in which he had been previously engaged) : — " The method I take to do this is not very usual : for, instead of using only comparative and superla- tive words, and intellectual arguments, I have taken the course (as a specimen of the political arithmetic I have long aimed at) to express myself in terms of number, weight, or measure ; to use only arguments of sense, and to consider only such causes as have visible foundations in Nature." It would be easy to adduce from other sciences analogous illustra- tions of the proposition which I have ventured to advance. Com- pare the natural theology of Derham, Paley, and the Bridgewater Treatises, all founded on the observation of natural phenomena, with the speculations of the ancient philosophers, or with the abstractions 170 and a priori arguments of Dr. Samuel Clarke. Compare the un- ravelling of early history by Niebuhr and Arnold with anything regarding history that had been done before, or the best practical treatises on politics and government of modern times with the elabo- rate but fantastic scheme of Plato's republic. If I have made too large a demand on your patience by dwelling on matters which have no special or exclusive relation to our body, you will, I hope, accept it as a sufficient apology that I have done so under the impression that whatever relates to the advancement of knowledge generally cannot be altogether uninteresting to those who are the living representatives of the great men by whom the Royal Society was founded, and who themselves now constitute the most ancient scientific institution in the world. Looking at what more particularly concerns ourselves, I may con- gratulate you on the results obtained during the last year. In the volume of the ' Philosophical Transactions' which is now in the course of publication, we find that there is scarcely any department of phy- sical knowledge which is not honourably represented ; at the same time that, besides the abstracts of the principal papers, many inves- tigations which have not been deemed to be of sufficient importance, or sufficiently original to have a place in our annual volume, but which nevertheless are of considerable interest, are recorded and published from time to time in the smaller volume bearing the title of * The Royal Society's Proceedings.' By means of this less pretentious publication many facts, many thoughts and suggestions are preserved, which might otherwise have been neglected or lost, but which, being thus pre- served, may prove to be of much value hereafter. Our weekly meetings have been well attended, and have been rendered more attractive by a practice which is not altogether new, but which has been more generally adopted than heretofore during the last Session ; I allude to that of the authors of papers communicated to us giving an oral or vivdvoce explanation of their contents, — those explanations being ren- dered more intelligible by a reference to diagrams, or to the apparatus used for experiments, and even by experiments actually displayed. Such illustrations are useful both to the authors and to others, by causing the subject-matter of the several communications to be better understood ; and they are useful in another way, inasmuch as they lead to conversations and discussions, and to the interchange of 171 opinion at the time, from which we may all of us derive something to think of, and reflect on afterwards. Having occupied so much of your time already, I do not feel jus- tified in making a further demand on it by entering into a recapitu- lation of what has been done in the way of scientific discovery during the last year. There is, however, one subject to which I am led to advert because it is of more than usual interest, not only on account of its connexion with scientific investigations, but also on other grounds. After an interval of two years, Captain M'Clintock and those who were associated with him have returned in safety from their voyage of discovery, and their investigations in the Arctic regions. The result has been that, although our most earnest wishes have not been realized, it cannot be said that our more reasonable expectations have been disappointed. There seemed to be no more than a small probability that any of those who accompanied Sir John Franklin when he quitted his native country in the year 1845 should be still alive in the dreary and inhospitable regions in which, after the loss of their vessels, they had been imprisoned. Captain M'Clintock's careful inquiries have fully dissipated whatever faint hopes might have been entertained of its being otherwise, leaving us only the poor consolation of knowing that the sufferings of these gallant spirits are at an end. As scientific discoverers, Captain M'Clintock and his officers have well fulfilled their mission, as is proved by the magnetic observations which Captain M'Clintock has already communicated to the Royal Society, and of which General Sabine, with his usual perspicuity, gave us some account at one of our evening meetings. In speaking of those engaged in the late expedition, I am unwilling to pass over in silence the name of Mr. Young, who, having been the commander of a merchant-ship, took so much interest in the pro- jected enterprise that he not only contributed j£500 towards defraying the expenses of it, but volunteered his personal services on the occa- sion, by acting as master of the vessel. Nor ought I to omit to notice the name of Dr. Walker, who, being engaged as surgeon, acted also as naturalist to the expedition, and availed himself of such scanty opportunities as those ice-bound countries afford of extending his researches in natural history. Of the results which he has been able to obtain I am not in a condition to give you an account at 172 present ; but they will, I doubt not, in due time be communicated to the public. The greatest honour which the Royal Society has to bestow, namely the Copley Medal, has been awarded to Professor Wilhelm Eduard Weber of Gottingen, foreign member of the Royal Society, for his investigations contained in his ' Maasbestimmungen ' and other researches in electricity, magnetism, acoustics, &c. The first work in which Professor Weber was engaged was ' The Theory of Undulations,' published in conjunction with his brother Ernest in 1825. This work is still one of standard authority. It contains not only a complete account of all that was previously known on the subject of waves in water, but is the repository of many original and important experiments throwing light on this subject. The volume contains also many valuable investigations in acoustics. Subsequently to this, Professor Weber communicated to Poggendorff's ' Annalen ' numerous memoirs containing his further observations in acoustics, among which were his experiments on the longitudinal vibration of rods and strings ; on reed organ-pipes ; on grave har- monic sounds ; and also his method of determining the specific heat of bodies by their sonorous vibrations. In this department of physical science he has been a worthy coadjutor of Chladni and Savart. In association with his brother Edward, then Anatomical Prosector in Leipsic, he in 1835 published the details of an anatomical, physical, and mathematical investigation of the mechanism of the human organs of locomotion, one result of which was the promulgation of a theory of animal progression more nearly in accordance with observed facts than any that had been proposed previously. On his association with M. Gauss in the Magnetic Observatory at Gottingen, Professor Weber devoted himself almost exclusively to the subject of magnetism and electricity. The annual volumes of the * Results of the Observations of the Magnetic Union,' published by these eminent philosophers between 1838 and 1843, contain the description of several new instruments, some of which have been the models of those which are now used in all observatories. They include also a great variety of important original researches. It ought not to be omitted that the researches of Gauss and Weber with reference to the transmission of electric signals did more to 173 excite attention to the practicability of an electric telegraph than anything that had been done previously. In 1846 Professor Weber published a memoir on "The Measures of Electro-dynamic Forces " (" Electrodynamische Maasbestimmun- gen "), a work not less remarkable for the original mathematical than for the experimental researches embodied in it. A high authority has pronounced this to be " one of the most important works both with regard to mathematical theory, and the practical application of it, that has been published in this department of science since the researches of Ampere ; " and the same authority has added, " His transformation of Ampere's law of electric action, so as to exhibit the analyses of the plus and minus elements in each stream, and his deduction thence of the law of statical from that of dynamical action, seems to me, both as a specimen of mathematical analysis and of physical philosophy, exceedingly beautiful." More recently Professor Weber has produced two additional memoirs on the same subject, one of which contains a mathematical and experimental investigation of the phenomena of dia-magnetism discovered by Faraday. PROFESSOR MILLER, As I have not the opportunity of presenting it to him in his own person, I request of you, as Foreign Secretary, to cause the Copley Medal which I now place in your hands to be conveyed to Professor Weber, with a request that he will be pleased to accept it as the indication of the very high estimation in which his scientific labours are held by the Royal Society of London. One of the Royal Medals has been awarded to Arthur Cayley, Esq., F.R.S., for his Mathematical Papers published in the Philosophical Transactions, and in various English and Foreign Journals. From the first institution of the Royal Society a large proportion of the papers communicated to them have related to Pure Mathe- matics ; and none have contributed more than these to maintain the credit of the Philosophical Transactions. Among writers of the present time, no one has been a more earnest or more successful labourer in this department of science than Mr. Cayley. His nume- rous papers on these subjects bear testimony to his unwearied indus- 174 try ; and the undivided opinion as to their value and importance held hy those who are best qualified to judge of them, sufficiently establishes Mr. Cayley's claim to be regarded as one of the most eminent and profound mathematicians of the age in which we live. Mr. Cayley is among the foremost of those who are successfully developing what may be called the organic part of algebra into a new branch of science, as much above ordinary algebra in generality as ordinary algebra is itself above arithmetic. The effect is a vast augmentation of our power over the comparison and transformation of algebraical forms, and greatly increased facility of geometrical in- terpretation. To give any full account of Mr. Cayley's labours would be im- possible, from mere want of space ; and such account, were it given, would be intelligible to none but the highest order of mathemati- cians ; moreover, you are well aware, it could not come from my own knowledge of the subject. I have, however, considered it my duty to lay something before you, in the most general terms of description, about these very remarkable papers, obtained from those who are competent to describe them. Mr. Cayley's memoirs relate almost exclusively to pure mathe- matics ; and a considerable proportion of them belong to the subject Quantics, defined by him to denote the entire subject of rational and integral functions, and of the equations and loci to which these give rise ; in particular the memoirs upon linear transformations and co- variants, and many of the memoirs upon geometrical subjects, belong to this head. Among the memoirs upon other subjects may be mentioned Mr. Cayley's earliest memoir (1841) in the Cambridge Mathematical Journal, " On a Theorem in the Geometry of Position," which contains the solution in a compendious form, by means of a determinant, of Carnot's problem of the relation between the distances of five points in space ; the memoir in the same Journal, " On the Properties of a certain Symbolical Expression/' which is the first of a series of memoirs upon the attraction of ellipsoids, and the multiple integrals connected therewith ; a memoir in Liouville's Journal, which contains the extension of the theory of Laplace's functions to any number of variables ; and the memoirs in the same two Journals, on the inverse elliptic integrals or doubly periodic functions. The earliest of the memoirs upon linear transformations was published 175 (1845 and 1846) in the Cambridge and the Cambridge and Dublin Mathematical Journals, and under a different title in * Crelle.' The antecedent state of the problem was as follows : — The theory of the linear transformations of binary and ternary quadratic functions had been established by Gauss, the same being in fact the foundation of his researches upon quadratic forms, as developed in the ' Recherches Arithmetiques ; ' and that of the linear transformations of quadratic functions of any number of yariables had been considered by Jacobi and others. A very important step was made by Mr. Boole, who showed that the fundamental property of the determinant (or, as it is now commonly called, discriminant) of a quadratic form applied to the resultant (discriminant) of a form of any degree and number of variables, — the property in question being, in fact, that of remaining unaltered to a factor pres, when the coefficients are altered by a linear transformation of the variables, or as it may for shortness be called, the property of invariancy : the theorem just referred to, suggested to Mr. Cayley the researches which led him to the discovery of a class of functions (including as a particular case the discriminant), all of them possessed of the same characteristic property. These functions, called at first hyperdeterminants, are now called invariants ; they are included in the more general class of functions called co- variants, the difference being that these contain as well the va- riables as the coefficients of the given form or forms. The theory has an extensive application to geometry, and in particular to the theory of the singularities of curves and surfaces. This theory for plane curves was first established (1834) by Pliickerupon geometrical principles ; the analytical theory for plane curves is the subject of a memoir by Mr. Cayley in * Crelle,' and of his recent memoir in the Phi- losophical Transactions, " On the Double Tangents of a Plane Curve," based upon a Note by Mr. Salmon. The corresponding geometrical theory for curves of double curvature and developable surfaces, was first established in Mr. Cayley's memoir on this subject in ' Liouville' and the ' Cambridge and Dublin Mathematical Journal.* The theory for surfaces in general, is mainly due to Mr. Salmon. Among Mr. Cayley's other memoirs upon geometrical subjects, may be mentioned several papers on the Porism of the in-and-circum scribed polygon, and on the corresponding theory in solido ; a memoir on the twenty- seven right lines upon a surface of the third order, and the memoir 176 in the Philosophical Transactions, " On Curves of the Third Order." The memoirs on Qualities in the ' Philosophical Transactions ' (forming a series not as yet completed) comprise a reproduction of the theory of covariants, and exhibit the author's views on the general subject. Mr. Cayley has written also a Report on the recent progress of theoretical Dynamics, published in the * Reports of the British Association' for 1857. MR. CAYLEY, In the name of the Royal Society of London, I request your acceptance of this Royal Medal, in testimony of the strong sense which they entertain of the value of your labours, and of the satisfaction which it affords them that so eminent a mathematician as yourself should be included in the list of their Fellows. The other Royal Medal has been awarded to Mr. George Ben- tham, F.L.S., for his important contributions to the advancement of Systematic and Descriptive Botany. The remarkable accuracy which distinguishes all Mr. Bentham's scientific researches, the logical precision that characterizes his writings, and the sound generalizations which his systematic works ex- hibit may be in a great measure traced to the influence of his uncle, the late celebrated legal theorist Jeremy Bentham, who directed much of his early studies, and under whose auspices he published one of his earliest works, * Outlines of a New System of Logic.' His mind was further imbued in youth with a love of Natural History, and especially Botany ; and this taste was cultivated and nourished by a study of the works of the elder DeCandolle. Fortunately for the cause of Botany in England, Mr. Bentham has devoted himself almost exclusively to that science; and to his excel- lent powers of observation, close reasoning, concise writing, and in- defatigable perseverance our country owes the distinction of ranking amongst its Naturalists one so preeminent for his valuable labours in Systematic Botany. Amongst Mr. Bentham's numerous writings, those hold the first rank which are devoted to the three great natural orders, Leguminosse, Labiatse, and Scrophulariaceee. These orders demanded a vast amount of analytic study ; for they are amongst the largest and most widely 177 distributed of the vegetable kingdom, and had been thrown into great confusion by earlier writers. They have been the subject of many treatises by Mr. Bentharn, and especially of two extensive works, the contents of which have lately been embodied in the " Systema Vegetabilium" of the DeCandolles. On their first ap- pearance these works secured for their author a European reputation, and will always rank high as models of skilful classification. It would occupy too much time to specify the very numerous monographs and papers which Mr. Bentharn has communicated to various scientific societies and periodicals in this country and on the Continent, and especially to the Linnean Transactions and Journal. That " On the Principles of Generic Nomenclature " may be noted as an example of his power of treating an apparently simple, but really abstract and difficult subject in a manner at once philosophical and practical. Mr. Bentham's most recent work, that on British Plants, is the first, on the indigenous Flora of our Islands, in which every species has been carefully analysed and described from spe- cimens procured from all parts of the globe ; it is distinguished for its scientific accuracy, advanced general views, and extreme simplicity, — a combination of qualities which can result only from an extensive series of exact observations, judiciously arranged and logically ex- pressed. MR. BENTHAM, The early volumes of the ' Philosophical Transactions ' contain numerous papers relating to Botany and the other sciences which are usually comprehended under the general designation of Natural History. As these sciences, but especially Botany, became more and more extended, it was thought desirable that another Institution should be called into existence, which might share with the Royal Society the privilege of promoting the cultivation of them, and of communicating to the world from time to time the progress which has been made in this department of knowledge : and such was the origin of the Linnean Society in the year 1788. The Royal Society, however, does not on that account feel the less interest in this class of scientific investigations. It is accordingly with great satisfaction that the Council have awarded to you one of the Royal Medals, and that, in the name of the Society, I now place it in your hands, in 178 testimony of their high appreciation of your researches, and of the respect which they have for you as a fellow-labourer in the field of science. On the motion of Mr. Faraday, seconded by Sir Henry Holland, the best thanks of the Society were voted to the President for his excellent address, and he was requested to permit the same to be printed. [For the Obituary Notices of Deceased Fellows the reader is referred to the end of the Volume.] The Statutes relating to the election of Council and Officers having been read, and Mr. Christie and Dr. Mayo having been, with the consent of the Society, nominated Scrutators, the votes of the Fel- lows present were collected. The following Fellows were reported duly elected Officers and Council for the ensuing year : — President. — Sir Benjamin Collins Brodie, Bart., D.C.L. Treasurer. — Major-General Edward Sabine, R.A., D.C.L. f William Sharpey, M.D. Secretaries.— ^ Qeorge Gabriel StokeSj Esq., M.A., D.C.L. Foreign Secretary. — William Hallows Miller, Esq., M.A. Other Members of the Council. — C. Cardale Babington, Esq., M.A. ; Rear-Admiral Sir George Back, D.C.L. ; Rev. John Barlow, M.A. ; Thomas Bell, Esq. ; Arthur Cayley, Esq. ; William Farr, M.D., D.C.L. ; Sir H.Holland, Bart.,M.D., D.C.L. ; Thomas Henry Huxley, Esq. ; Sir Roderick I. Murchison, M.A., D.C.L. ; Thomas Webster, Esq., M.A. ; Rev. William Whewell, D.D. ; Alex. William William- son, Ph.D.; Rev. Robert Willis, M.A.; Sir William Page Wood, D.C.L. ; The Lord Wrottesley, M.A. ; Colonel Philip Yorke. jcS bpPn VO 180 The following Table shows the progress and present state of the Society with respect to the number of Fellows : — Patron and Honorary. Foreign. Having com- pounded. Paying £2 12s. annually. Paying £4 annually. Total. December 1, 1858.. Since elected 9 50 365 + 4 7 275 + 13 706 + 17 Since deceased .... 2 -3 -16 — 11 -32 November 30, 1859.. 7 47 353 7 277 691 December 8, 1859. Sir BENJAMIN C. BRODIE, Bart., President, in the Chair. The President announced that, under the provisions of the Charter, he had appointed the following Members of the Council to be Vice- Presidents : — Thomas Bell, Esq. Sir Roderick I. Murchison. Major-General Sabine. The Rev. William Whewell, D.D. Sir William Page Wood. The Lord Wrottesley. 181 The following communications were read : — I. "On the Analytical Theory of the Attraction of Solids bounded by surfaces of a Class including the Ellipsoid." By W. F. DONKIN, Esq., M.A., F.R.S., F.R.A.S., Savilian Professor of Astronomy in the University of Oxford. Received September 2, 1859. (Abstract.) The surface of which the equation is f(*,y,*,M)=0, . . ...... (1) is called for convenience " the surface (ht k)" The space, or solid, included between the surfaces (hlt k), (A2, k), is called " the shell \h' /' " an(* ^at ^nc^U(^e^ between the surfaces (h, A-2), (h, £2) is called " the shell (h, ^2Y " [This notation is borrowed, with a slight alteration, from Mr. Cayley.] It is assumed that the equation (1) represents closed surfaces for all values of the parameters h, k, within certain limits, and that (within these limits) the surface (h, k) is not cut by either of the surfaces (h+dh, k), (h, k+dk). It is also sup- posed that there exists a value h^ of A, for which the surface (hx, k) extends to infinity in every direction. Lastly, it is supposed that if k be considered a function of x, y, z, h, by virtue of ( 1 ), the two fol- lowing partial differential equations are satisfied : dk in which q>(Ji) is any function of h (not involving k), and n is any constant independent of h and k. The following propositions are then demonstrated : — The potential, on a given external point, of a homogeneous solid bounded by the surface (h, k), varies as the mass of the solid, if h vary while k remains constant. The potentials, on a given external point, of the homogeneous shells (h^ ^2\ (X M are proportional to the masses of the shells. 182 on an m- The homogeneous shell (hy ,2 ) exercises no attraction \ *W terior mass. The external equipotential surfaces of the homogeneous infinite- simal shell ( h.zy i +dk J, are the surfaces (h, k)y in which h is arbi- trary and k invariable*. The potential of the homogeneous infinitesimal shell ( A2, , upon an exterior point, is dh n and upon an interior point, is (In these expressions ^(h) is ew J , and h at the lower limit in the first, is the parameter of the surface (h, k) which passes through the attracted point. The density of the shell is supposed to be unity.) / &"\ The potential of the finite homogeneous shell ( A2, *, J (density = 1 ) upon an exterior point (£, rj, £), is h"«> dh , S>h* dh in this expression it has been assumed (for simplicity) that h^ is inde- pendent of k. Also h"y h1 are the values of h corresponding to kny k'9 when h and k vary subject to the relation f (£, 77, £, hy k)=Q ; and ky in the last integral, is the function of hy £, 17, £ determined by this relation. The differential equations (2) are satisfied in the case of the ellip- soid. For if we put its equation in the form ^2 4- ^ A- *2 — k it is evident on inspection that ^_L^ + ^= dx* dy* dz* * tt is known that the last two propositions imply the first two (see Mr. Cayley's " Note on the Theory of Attraction," Quarterly Journal of Mathematics, vol. ii. p. 338) ; though this is not the order of proof in the present paper. 183 dk\ 4= + dk and In this case we find above general expressions lead to the known results. , and the II. Supplement to a Paper, read January 27, 1859, " On the Thermodynamic Theory of Steam-engines with dry Satu- rated Steam, and its application to practice." By W. J. MACQUOEN RANKINE, C.E., F.R.S. &c.* (Abstract.) This supplement gives the dimensions, tonnage, indicated horse- power, speed, and consumption of fuel, of the steam- ships whose engines were the subjects of the experiments referred to in the original paper. Results are arrived at respecting the available heat of combustion of the coal employed, and the efficiency of the furnaces and boilers, of which the following is a summary : — Available beat of Total heat of com- combustion of 1 Ib. Available bustion of 1 Ib. of of coal in ft.-lbs. heat, total No. of experiment. Kind of boiler. coal in ft.-lbs., estimated from chemical compo- sition. computed from efficiency of steam and weight of coal burned per heat, = effi- ciency of furnace and boiler. I.H.P. I. {Improved Marine "I Boilers of ordi- V 10,000,000 5,420,000 0-542 III. nary proportions.] 10,000,000 5,300,000 0-53 fBoiler chiefly com- ""I posed of small J II. J vertical water- 1 tubes, with very j 11,560,000 10,110,000 0-88 great heating (^ surface. J Available Heat of Combustion of 1 Ib. of coal 1,980,000 ft.-lbs. Efficiency of steam x Ib. coal per I. H. P. per hour * Phil. Trans. 1859, p. 177 ; and Proceedings of the Royal Society, vol. ix. p. 626. 184 III. Supplement to a Paper, read February 17, 1859, " On the Influence of White Light, of the different Coloured Rays and of Darkness, on the Development, Growth, and Nutri- tion of Animals*/' By HORACE DOBELL, M.D. &c. Communicated by JAMES PAGET, Esq. Received Sep- tember 23, 1859. The apparatus used in the following experiments, was described in my Paper ; but in the present instance, only two of the cells were employed, viz. that exposed to ordinary white light, and that from which all light is excluded. In order more effectually to prevent the possible admission of light, the following precautions were adopted with the dark cell : — 1. The perforated zinc floor was covered with thick brown paper. 2. The under surface of the lid was lined with black cloth, to secure accurate adjustment when shut. 3. The opaque black glass was covered with an additional coat of black oil- paint. 4. The lid was never opened in any light except that of a candle or of gas. March 20th, 1859.— A number of ova of the Silkworm (Bombyx mori), all of the same age, were placed in each of the two cells. No change was observed until May ISth (sixty days after the commence- ment of the experiments), when one larva emerged from the ovum in each cell ; and during twelve days, larvae continued to emerge in the light and in the dark at the same rate. June 9th. — Sixteen larvae, as nearly as possible of the same size, were selected in each cell, and the rest removed. The experiments then proceeded with these thirty-two individuals, and no death occurred from first to last. * Proceedings of the Royal Society, vol. ix. p. 644. 185 The following Table shows the day on which each larva began to spin ; the day on which the perfect insect Escaped from the pupa ; and hence the number of days occupied by the metamorphosis. Light. Darkness. Day of beginning to spin. Day of escape of the Moth. Number of days occupied by meta- morphosis. Day of beginning to spin. Day of escape of the Moth. Number of days occupied by meta- morphosis. July 1 July 18 1 8 days inclusive June 30 July 18 1 9 days inclusive , 2 19 18 PI » 30 » 18 19 , 2 19 18 n n 30 18 19 , 2 18 17 „ 30 18 19 , 2 18 17 ' „ 30 21 22 , 2 19 18 » July 1 18 18 2 19 18 » 1 18 18 3 19 17 2 18 17 3 21 19 2 19 18 4 20 17 2 20 19 4 20 17 2 19 18 4 20 17 2 20 19 , 4 21 18 2 21 20 » 4 21 18 3 21 19 » 5 21 17 n 3 20 18 ,. 6 '„ 24 19 H 4 21 18 » From this it is seen that the mean period occupied by the meta- morphosis in the darkened cell was eighteen days fifteen hours, and in the light cell seventeen days sixteen hours. The longest and shortest periods in the darkened cell twenty-two days and seventeen days, in the light cell nineteen days and seven- teen days. June 9th. — On selection of sixteen of the largest larvee from the inhabitants of each cell, it was noted that, when sixteen were selected from the darkened cell and several of similar size removed, only four could be found as large in the white cell, the remaining twelve selected were therefore of a rather smaller size. This difference in the two cells became less obvious afterwards, but, throughout the experiments, there was a slight difference of size in favour of the darkened cell. With these exceptions, no difference could be detected between the results obtained in the cell from which light was completely excluded and in that exposed to its full influence. The larvse, the silk produced, and the moths from the two cells, 186 when placed side by side, could not be distinguished from one another. The ova were of the same colour when first deposited, and under- went the same changes of appearance, at the same time, in the dark and in the light. So far, therefore, as the direct agency of light is concerned in the development, growth, nutrition, and coloration of animals, the results of these experiments closely correspond with those already recorded in my Paper. IV. " Ou the Effects produced in Human Blood- corpuscles by Sherry Wine, &c." By WILLIAM ADDISON, Esq., F.R.S., Fellow of the Royal College of Physicians, London. Re- ceived September 10, 1859. (Abstract.) The author has found that when a small drop of fresh blood is placed beside a similar drop of sherry wine on a slip of glass, and viewed with the microscope, after being covered as usual with a thin piece of glass, certain changes are seen to take place in the blood as it mingles with the wine, which are thus described : — " In those parts where the wine is mingling with the blood — at the outer edges of the mass — various altered corpuscles will be seen. They float in the fluid, separated from each other, having now no longer any disposition to adhere together in rolls. Their outlines are altered, and sundry markings appear in their interior. After a short time — perhaps ten minutes, sometimes sooner — numerous cor- puscles will be observed throwing out matter from their interior ; two, five, or ten molecular spots fringing their circumference. Some of these molecules grow larger and seem coloured ; others of them elongate into tails or filaments, which frequently attain to an extra- ordinary length, and wave about in a very remarkable manner. They all terminate, at the extremity farthest from the corpuscle, in a round globular enlargement. A single corpuscle may very frequently be seen with five or six of these tails. " During the observation of these phenomena, numerous mole- cular particles are seen continually passing from the corpuscles ; they 187 float about in, and disturb the transparency of the fluid : moreover, they have an extremely vivid movement. " At the expiration of half an hour, many of the tails or filaments are seen assuming the form of a necklace of beads ; and those also, separating from the corpuscles, float about with a singular indepen- dent movement in the fluid." When blood is similarly mingled with a fluid consisting of two parts of sherry wine and one part of a solution made with a grain and a half of common salt and a grain of bicarbonate of soda to half a fluid ounce of water, the transparency of the fluid part of the blood is not altered, " but the corpuscles are changed in appearance, and the tails or filaments which are now seen issuing from them are gene- rally thicker and much more conspicuous than when the wine alone is used. The molecules which separate from the corpuscles are larger, and the tails which break away from the corpuscles upon any slight motion of the fluid, present various dumb-bell, necklace-like, serpentine, globular, and other shapes." Under particular but accidentally produced conditions of the mingled fluids, the author has " repeatedly seen the tails suddenly retract, not into the interior of the corpuscle, but into a globular ball at its side Sometimes the tail shortens to only half its length, becoming in a corresponding degree thicker." The tail in thus shortening may become bulged in the middle of its length, ex- hibiting at that part a globular or discoid enlargement. This glo- bule or disc may then burst, and in such case the blood-corpuscle finally exhibits only a small round particle remaining at the point of its circumference from which the tail had proceeded. After describing in detail various other appearances which he noted in his experiments, and which, as well as those above men- tioned, are delineated in several drawings which illustrate the paper, the author thus states his views as to the nature of the phenomena observed : — " In these experiments, a mixture of a saline solution and sherry wine, or the wine alone, is added to a drop of fresh blood. The ad- dition must change the properties of the fluid in which the corpuscles naturally swim. The change in the fluid produces changes in the corpuscles, shown by their altered appearance, their indisposition any longer to adhere in rolls, and the various markings seen within them. 188 Some time after these changes the corpuscles discharge molecular particles, and emit tails or filaments, which, separating from the corpuscles, materially alter the transparency and aspect of the fluid. " The first alteration of the fluid element of the blood — that, namely, produced by the addition of the extraneous fluid — causes no visible troubling or change in it ; but the second alteration, which consists in the appearance of a great number of molecular particles, is visibly produced by the agency of the corpuscles. The molecular particles are seen coming out of the corpuscles, separating from them, and disturbing the transparency of the fluid." In corroboration of his opinion that the filaments and molecules are emitted from the blood-corpuscles, and not produced by a preci- pitation or solidification of coagulable matter in the plasma, the author especially draws attention to the fact that, so far as he ob- served, the molecules appear only in those parts of the fluid where the corpuscles have been altered and are fringed with similar mole- cules, or emitting tails ; whilst in other parts, where such changes are not occurring in the corpuscles, the fluid is perfectly clear, and free from molecules. Moreover, the emission of tails and molecules is not the result of a breaking up of the corpuscles ; for many of the latter may be seen emitting long tails without any alteration of their natural form ; and although no doubt the corpuscles are finally broken up, this process does not take place sooner in those with tails than in those which have none. In connexion with his present observations, the author relates two cases of febrile and inflammatory disease (already reported by him in the ' London Medical Gazette ' some years since), in which molecular matter existed abundantly in the liquid part of the blood. The molecules in these cases, as in his present experiments, he be- lieves to have proceeded from the blood-corpuscles, and likewise through the operation of some abnormal influence, which, however, must have acted upon the corpuscles during their circulation in the living body. The author next refers to certain inferences from the foregoing observations calculated to elucidate questions in pathology and practical medicine, which, however, he has already made known in his Gulstonian Lectures. 189 To produce the effects described, brown sherry of the best quality was employed. Inferior sherry wines alter the outline of the cor- puscles, but do not cause the production either of tails or molecules. With other sherry wines of a better kind, the author finds it preferable to mix them with a fourth or a fifth part of the saline solution instead of one-third ; he has tried port-wines and various mixtures of brandy and water, with and without sugar, but almost always without the effect here described. V. "Researches on the Phosphorus-Bases." — No. VII. Tri- phosphonium- Compounds. By A. W. HOFMANN, LL.D., F.R.S. &c. Received October 18, 1859. In several previous communications I have submitted to the Royal Society the results which I have obtained in examining the deport- ment of triethylphosphine with dibromide of ethylene, as the proto- type of diatomic bromides. I have shown that the final product of this reaction is a diatomic salt corresponding to two molecules of chloride of ammonium. The further prosecution of the study of triethylphosphine in this direction has led me to investigate the derivatives generated by the phosphorus-base, when submitted to the action of triatomic chlorides, bromides, and iodides. The most accessible terms of this group being chloroform, bromo- form, and iodoform, the changes of triethylphosphine under the in- fluence of these agents have more especially claimed my attention. Action of Iodoform on Triethylphosphine. Both substances unite with energy at the common temperature. In order to avoid the inflammation of the phosphorus-base, small quantities of the materials should be mixed at a time. The products of the reaction vary with the relative proportions of the two sub- stances. By adding gradually crystals of iodoform to a moderate bulk of triethylphosphine until a new addition produces no longer an eleva- tion of temperature, a viscous mass of a clear yellow colour is obtained, which, when treated with alcohol, changes to a white powder of cry- 190 stalline aspect ; these crystals are easily soluble in water, difficultly soluble in alcohol, and insoluble in ether. Two or three crystalliza- tions from boiling alcohol render them perfectly pure. The analysis of this body has led me to the formula ^38 H46 Pg I8, which represents a compound of one molecule of iodoform, and three molecules of triethylphosphine, 3CI3H18P+C2HI8=C88H16P3Ia. Triethyl- Iodoform. New Compound, phosphine. Iodoform thus fixes three molecules of triethylphosphine, giving rise to the formation of the tri-iodide of a triatomic metal, of a tri- phosphonium corresponding to three molecules of chloride of ammo- nium. (C2H) (£4^5)3 I po (C4H5)3^P3 -(PiH.), in 13. The aqueous solution of the iodide yields with iodide of zinc a white crystalline precipitate which is difficultly soluble in water, and appears to be slightly decomposed by recrystallization. It consists of one molecule of the triatomic iodide and three molecules of iodide of zinc, C38H46P3I3, 3ZnI. By treating the tri-iodide with the various salts of silver, a series of triatomic compounds is easily obtained, which contain the different acids. The trichloride furnishes with dichloride of platinum a pale yellow precipitate, which is insoluble in water, but dissolves in boiling con- centrated hydrochloric acid. From this solution it is deposited on cooling in brilliant rectangular plates, which contain C38H46P3Cl3,3PtCl2. I have vainly tried to produce a trioxide which would correspond to the tri-iodide. The tri-iodide is promptly attacked by oxide of silver, with formation of iodide of silver, and of an exceedingly caustic fixed base, which remains in solution. This base no longer belongs to the same series. By treating its solution with hydriodic acid, or with hydrochloric acid and dichloride of platinum, it is at once perceived that the action 191 of the oxide of silver has profoundly changed the original system of molecules. Hydriodic acid no longer produces the salt difficultly soluble in alcohol ; by evaporating the solution a crystalline residue is obtained, which easily separates into a viscous, extremely soluble substance, and splendid crystals of an iodide, very soluble in water and alcohol, but insoluble in ether. The analysis of this iodide has proved it to contain CHPI U18 I. This formula represents the iodide of methyl-triethylphosphonium, which was formerly obtained by M. Cahours and myself, by acting with iodide of methyl upon triethylphosphine. The alkaline liquid, obtained by the action of oxide of silver upon the tri-iodide, when saturated with hydrochloric acid, yields no longer the platinum salt, difficultly soluble in water but soluble in hydro- chloric acid. In a dilute solution no precipitate whatever takes place, and only after considerable evaporation well-defined deep orange-yellow octahedrons are deposited, which contain CUH18PC1, PtCl2= Cl, PtCla. From these results it is obvious that the triphosphonium-salt, when submitted to the action of oxide of silver, passes over into a monophosphonium-compound. The latter is not the sole product of the reaction ; I have already alluded to the viscous deliquescent substance which accompanies the iodide of methyl-triethylphospho- nium. This is an iodide, which, in the solution produced by the action of oxide of silver upon the original tri-iodide, exists in the form of oxide. The latter substance is easily recognized by evaporating the solution of oxide of methyl-triethylphosphonium, and adding a concentrated solution of potassa, when the oily globules characteristic of the dioxide of triethylphosphonium separate, which disappear immediately on addition of water. The metamorphosis of the tri-iodide, under the influence of oxide of silver, is represented by the following equation : — 192 •(C.Hy'1 -| |-C2H, (C.H.). (C.H.), =3Agi+ %£ p The tri-iodide which forms the subject of this Note is not the only product of the reaction between iodoform and triethylphosphine. There are other compounds formed, especially when the iodoform is employed in great excess. The nature of these bodies, which may be divined from the examination of the corresponding compounds in the diatomic series, is not yet fixed by experiment. I have satisfied myself that chloroform and bromoform act like iodoform upon triethylphosphine. The phosphorus-base acts, even at the common temperature, upon tribromide of allyl. The mixture of the two bodies solidifies into a crystalline mass, in the examination of which I am engaged. The reactions which I have pointed out in this Note have induced me to extend my experiments to tetratomic bodies. The chloride of carbon, C2 C14, obtained by the final substitution of chlorine for the hydrogen in marsh-gas, appeared to promise accessible results. On submitting this body, remarkable for its great indifference under ordinary circumstances, to the influence of triethylphosphine, I have observed with astonishment a most powerful reaction. Every drop of triethylphosphine which is poured into the chloride of carbon, hisses like water falling upon red-hot iron. On cooling, the mixture solidifies into a mass of white crystals, which will be the subject of a special communication. December 15, 1859. Sir BENJAMIN C. BRODIE, Bart., President, in the Chair. Samuel Husbands Beckles, Esq., was admitted into the Society. In accordance with Notice given at the last Meeting, the Right Honourable Edward Lord Stanley, Member of Her Majesty's Privy Council, was proposed for election and immediate ballot ; and the ballot having been taken, his Lordship was declared duly elected. 193 The following communications were read : — I. " Note respecting the Circulation of Gasteropodous Mollusc a and the supposed Aquiferous Apparatus of the Lamelli- branchiata." By M. H. LACAZE DUTHIERS. Communicated by Professor HUXLEY. Received October 19, 1859. A memoir upon the aquiferous system and the oviducts of Lamelli- branchiate Mollusks by Messrs. Rolleston and Robertson, was read before the Royal Society at the Meeting on the 3rd of February, 1 859. The abstract of this memoir, contained in the * Annals and Magazine of Natural History/ reached me in the month of July; and I was not a little surprised to find that a structure which I had so elaborately stu- died in the course of my various journeys to the sea-shore, and which I had carefully described in a number of species, was something quite different from what I had imagined it to be. Without entering into minute anatomical details, which would not tend to elucidate the question, I find that Messrs. Rolleston and Robertson consider that the organs, the ducts, and the orifices supposed to be the ovaries or their excretory ducts, are, in fact, nothing but an aquiferous appa- ratus, and that the openings placed on each side of the foot are the excretory orifices of this system. They discover elsewhere the ducts whose office is to convey away the products of the genital glands. The enunciation of an opinion so opposed to what I, in common with many other authors, had maintained, seemed to require a recur- rence to direct observation. But on repeating my examination of Cardium edule, Tellina solidula, Mactra stultorum, and Donax ana- tina, I have precisely verified my previous conclusions. On throwing injections into the genital orifices, the sexual glands have become turgid ; and on examining fragments of such injected genital glands microscopically, the injected substance was seen mixed with the ova or spermatozoa. These facts may be observed with especial ease in Cardium edule. In addition to this, I have seen ova actually laid by living females of Modiolce and Mytili, one of the valves of whose shell was removed, on irritation of the genital orifice ; and in others the ova or the spermatic fluid may be made to pass out of their orifices, at the breeding season, by pressing gently upon the foot. In Spondylus gcederopus the genital orifice is situated in the sac 194 of Bojanus, and I had great difficulty in finding it when investigating this subject. It was, in fact, only by chance that I opened the sac of Bojanus and observed a little rose-coloured cylinder issuing from an orifice in its interior. This cylinder, like a thread of vermicelli in aspect, was composed of reddish ova mixed with mucus, and agglomerated. I might multiply examples, but it seems to be use- less to do so, for I should simply reproduce the facts which I have brought forward in the memoir which I published in the * Annales des Sciences Naturelles,' on my return from a long stay in the Balearic isles. In this memoir, besides, I have not merely drawn attention to the circumstance, that after oviposition the aspect of the gland changes completely, which might lead an observer to mistake the apparatus of reproduction for something quite different, but I have given figures of this condition of Pecten varius, &c. In fine, I believe that the structure of the male and female organs of the Lamellibranchiate Mollusca is such as it was described to be before the observations of Messrs. Rolleston and Robertson. But does the system of aquiferous vessels, whose occurrence in the Mollusca has been sometimes admitted, sometimes denied, really exist in the Acephala ? In the abstract to which I refer, those cita- tions, which doubtless existed in the memoir, have not, and probably could not have appeared. It is well known that the belief in this sup- posed aquiferous system has been gradually becoming weaker. The necessity of explaining the extreme dilatation and contraction of the bodies of molluscous animals led anatomists to seek for and describe such a system ; but at present the explanation of these facts is found in the direct mixture of water with the blood, or the ejection of the latter liquid. MM. Leuckart and Gegenbaur have made observations tending to prove the occurrence of this process in the Pteropods ; M. Langer of Vienna has published a special memoir on the circulation of Anodon, and the great point he makes out is the passage of water into the blood by the intermediation of the organ of Bojanus. I believe that I have demonstrated in Dentalium the orifices by which the direct communication of the circulatory apparatus with the ex- terior of the body takes place ; and lastly, I have found a Gasteropod, and one which assuredly occupies a very high place in that group, which presents the same arrangement. 195 I hope to be able before long to bring out a complete Monograph of the anatomy of Pleurobranchus aurantiacus, in which the exist- ence of an external orifice of the circulatory apparatus shall be put beyond doubt. As the figure which accompanies this Note shows, a very small orifice (b, fig. A, and c, fig. B) with a raised rim is visible above the external genital organs and in front of the principal branchial vein. This orifice, hidden by the contractions of the body, is very conspicuous in the dead animal. On injecting milk or any other liquid by it, the fluid is seen always to enter the heart ; and on slitting up the branchial vein, there is seen within it an aperture (d, fig. B) leading into a little canal which is connected with the external aperture, and is the channel whereby the fluid injected enters the heart. I have varied the method of injection in every possible way, and always with the same result. I cannot conceive that there is any rupture of the parts or any extravasation of the injection, so that I believe (as may be verified in spirit specimens) that in the Pleurobranchus the circulatory apparatus communicates directly with the exterior. The demonstration of a direct communication between the exterior and the circulatory apparatus, renders the assumed existence of an VOL. X. P 196 aquiferous system a priori less necessary, in order to explain the great changes of volume of the body of Mollusks. But I believe that, in addition, microscopic examination will show the direct con- tinuity of the genital glands with the lateral orifices placed at the base of the foot in the Lamellibranchiata. This communication of the vascular apparatus with the external water, has a very important bearing on the history of the nutritive processes. The physiological conceptions derived from the study of the higher animals are singularly affected by finding creatures which can at will throw out a portion of their blood, or, on the contrary, dilute with water that which is, par excellence, the nutri- tious element. This would be sufficient to prove, were it necessary to do so, how wide is the difference between the vital processes of the lower and of the higher animals. EXPLANATION OF THE FIGURES. A. Pleurobranchus aurantiacus, seen in a side view. a. Heart. b. External orifice of the sanguiferous system, placed before the branchiae and above the genital organ. B. Enlarged view of the heart, branchial vein, &c. a. Auricle. b. Ventricle. c. External opening through which fluid may be injected into the heart. d. Branchial vein laid open at this part to show the internal opening of the canal which leads from the external orifice c. e. Penis. /. Part of the branchial vein, unopened. II. " On the Repair of Tendons after their subcutaneous divi- sion." By BERNARD E. BROADHURST, Esq., F.R.C.S. Communicated by T. BLIZARD CURLING, Esq. Received November 4, 1859. (Abstract.) The results of the experiments which are recorded by the author are divided into three classes, which tend to show — 197 1st. That a tendon, having been divided, may reunite without leaving permanently a cicatrix. 2ndly. That the uniting new material may be drawn out to any required length, and in such case may, under gradual and carefully regulated extension, even acquire the thickness of the tendon itself; but that if the divided ends are widely separated after the section, and so remain, reunion will not take place. Srdly. That the addition of new tendon does not impair the strength of the muscle, unless the length be more than sufficient, in which case it occasionally weakens the muscle. The process of reunion is explained, and the appearances pre- sented by the tendon in the various stages of reunion are detailed and illustrated by coloured drawings. Preparations of the parts operated on were also exhibited. The author concludes that, when the divided ends of the tendon are held in apposition and the limb is kept at rest, reunion will take place without leaving a cicatrix ; but that when extension is made, the new material becomes organized, and persists as a permanent structure. III. " On the Curvature of the Indian Arc." By the Venerable JOHN H. PRATT, M.A., Archdeacon of Calcutta. Com- municated by Professor STOKES, Sec. R.S. Received November 8, 1859. (Abstract.) In a paper published in the Philosophical Transactions for 1855, in which the author calculates the effect which the attraction of the mountain mass north of India has upon the plumb-line at stations in the plains on the south, he applied the deflections as corrections to the astronomical amplitudes, to ascertain what influence they would have upon the determination of the curvature of the Indian Arc of Meridian. The method he adopted was to compare together the two measured arcs between Kaliana and Kalianpur, and between Kalianpur and Damargida. The calculation brought out an ellipse of which the ellipticity is -^-$. Colonel Everest had deduced by a comparison of the same arcs, but with uncorrected amplitudes, an 198 ellipticity y^g. These two values are on opposite sides of the mean elliptieity for the whole earth, from which they differ by about f ths and -£ths of the mean. In these calculations the ellipses are found which exactly accord with the measured lengths and the corrected latitudes in the one case, and in the other the latitudes uncorrected for deflection. A more correct method has been followed by Captain A. Clarke, R.E., in the volume of the Ordnance Survey just published by Lieut. Colonel James, R.E. Captain Clarke takes the latitudes of the three stations mentioned above, as corrected for mountain attraction by Archdeacon Pratt, and supposing the corrected latitudes as well as the elements of the mean ellipse subject to error, he determines, according to the method of least squares, the ellipse which best corresponds with the mean ellipse and with the three corrected latitudes. The resulting ellipse depends of course upon the height attributed to the mean ellipse, which is left arbitrary, to be assigned at the end of the cal- culation. In this way Captain Clarke shows that it is possible to obtain an ellipse which differs much less from the mean ellipse, and yet which makes the differences between the three latitudes cal- culated from the ellipse and the observed latitudes corrected for deflection, very small. Since this calculation was made by Captain Clarke, the author communicated to the Royal Society an approximate estimate of the effect of the deficiency of matter in the ocean south of Hindostan, on the plumb-line. On seeing Captain Clarke's result, he felt anxious to ascertain what effect this new disturbing cause would have upon it. The present paper contains a repetition of the calculations of Captain Clarke, with the additional corrections to the latitudes due to the defect of attraction of the ocean introduced into them. Capt. Clarke's result, the author finds, is thereby improved, the ellipse obtained coming out somewhat nearer to the mean ellipse, while the errors in the latitudes, which already were very small, are still further reduced. The following are the values of the semi-axes a b (infect) and of the reciprocal of the ellipticity corresponding, — I. to the mean ellipse, as determined by Captain Clarke ; II. to the first of the two ellipses (corresponding to two different degrees of importance assigned to the mean ellipse) obtained by Captain Clarke by combining the mean ellipse with the Indian Arc ; III. to the ellipse II. recalculated by 199 the author, with the additional correction for ocean attraction introduced. a. 6. b i a — b. I. ... 20926500 20855400 294 II. ... 20920328 20846522 2837 III. . . . 20919988 20846981 286-55 The residual errors of latitude at Damargida, Kaliana, and Kali- anpur, which in Captain Clarke's ellipse were +1"'05, — 0"'95, + 1"-20, are now reduced to + 0"'93, _0"-37, +0"74. In conclusion, the author calculates the distance of a point in the latitude of Kaliana from the centre of the earth in the three ellipses, and finds it to be near 7000 feet greater in the ellipses II. and III. than in the mean ellipse I. That deviations to such an extent as this from the mean ellipse should actually occur he thinks likely enough, and he is not disposed to have recourse to some yet un- discovered cause to reconcile the Indian Arc with the mean ellipse. The occurrence of marine fossils in mountains and elevated regions, shows that great changes of level of the land relatively to the water have actually taken place ; and it seems unlikely that an extensive internal change in the state of the earth would cause an upheaval or depression of the land or the water alone ; it might rather be expected that both would be affected, though unequally. Hence the absolute change of distance of the land from the centre of the earth may have been much greater than the elevation relatively to the water, while the phenomena adduced indicate that even the latter must have been very great. IV. " Comparison of some recently determined Refractive Indices with Theory." By the Rev. BADEN POWELL, M.A., F.R.S., F.G.S., F.R.A.S., Savilian Professor of Geometry in the University of Oxford. Received November 17, 1859. In a series of papers inserted in the Philosophical Transactions (1835, 1836, 1837), and afterwards, in a more correct and complete form, in my Treatise ' On the Undulatory Theory applied to the Di- spersion of Light' (1841), I endeavoured to investigate the great problem of the explanation of the unequal refrangibility of light on 200 the principles of the undulatory theory, as proposed by M. Cauchy about 1830, by numerical comparison with the indices observed, more especially in cases of the most highly dispersive media then examined. The general result then arrived at was, that while the theory applied perfectly through an extensive range of media of low and moderate dispersive power, it did not apply well to those of higher ; and to the highest in the scale (which of course formed the true test of the theory) it did not apply within any allowable limits of accuracy. Since that time little has been done towards prosecuting the subject. In the experimental part of the inquiry, about 1849, I had ob- served the indices for a few new media*; but these were not high in the scale ; yet though perhaps thus of little importance, I have now thought it as well to go through the calculation for them : the results are of the same general character as just described. Soon after, finding that my friend, the Rev. T. P. Dale, F.R.A.S., was desirous to carry on some researches of this kind, I placed at his disposal the apparatus with which I had determined all my in dices f. In 1850 that gentleman communicated to the Royal Astronomical Society a short general account of his observations | relative to some substances not very high in the scale. In 1858, Mr. Dale, in conjunction with Dr. J. H.Gladstone, F.R.S., presented to the Royal Society § a valuable series of determinations, evincing highly interesting results relative to the change of refractive power in various substances under different temperatures. None of these media being high in the scale, they have little bearing on the main object of my inquiries. In two cases (viz. water and alcohol) the indices agree so closely with mine, that it was not worth while to recalculate them. In two other cases I have carried out the numerical comparison, which affords a good agreement with the theory. Very recently the same gentlemen have, however, published some * See British Association Reports, 1850, Sect. Proc. p. 14. f Described and figured, British Association Reports, 1839. % Notices, vol. xi. p. 47. § Phil. Trans. 1858. 201 observations on several other media, especially phosphorus, a sub- stance at the very summit of the scale, for which I had long been extremely desirous to obtain some determinations of indices*. Among these results only two sets are in a form in which they can be made available for comparison with theory. These are the indices for the standard rays in bisulphide of carbon, and for solution of phos- phorus in that medium, which I have now calculated theoretically. The results (given in the sequel) in both cases indicate discre- pancies between theory and observation too great to be due to any reasonable allowance for error ; and we are confirmed in the con- clusion before arrived at, that, for highly dispersive substances, the theory, IN ITS PRESENT STATE, is defective. But these comparisons are all made by means of the same formula employed in my former researches, viz. that derived from Cauchy's theory by Sir W. R. Hamilton, which he communicated to me, and which I explained in a paper in the Philosophical Magazine f. Considering the unsatisfactory condition in which the question was left when tried by the test of the higher media in my former inquiries, it is a matter of some surprise that in the long interval since the publication of those results no mathematician has been in- duced to revise the theory. Some criticisms indeed were advanced by Mr. Earnshaw^;, and others by Prof. Mosotti and the Abbe' Moigno§, bearing on the general principle. Sir W. R. Hamilton's formula in particular was founded on certain assumptions con- fessedly but approximate. It remains then a promising field for inquiry to analysts, whether a better formula might not be deduced, or other improvements made in the general theory, by which a method applying so well to lower cases might be made equally successful for the higher. Results of calculation, for Ether, Hydrate of Pheny I, Oils of Spike- nard, Lavender and Sandal-wood, Benzole, Bisulphide of Carbon, and Solution of Phosphorus in that medium. Three indices assumed from observation, viz. /u , p. and p. , give the medium constants, viz. * See Phil. Mag. July 1859. t Vol. viii. N. S. March 1836. J See Phil. Mag. April 1842 and August 1842. § See British Association Reports, 1849, Sect. Proc. p. 8. 202 The values of the wave-length constants A and B for each ray, independent of the medium, are taken from my Treatise (Undulatory Theory applied to Dispersion, &c., Art. 270). Comhining these, we obtain AD and BD' for each ray in the medium. Thence Sir W. R. Hamilton's formula (ib. Art. 237) gives for any ray, the upper sign being used for rays above F, the lower for those below. Ether. — Dale and Gladstone. /i. ftav s\Ay. Observation. Theory. B 1-3545 C 1-3554 1-3544 -•0010 D 1-3566 1-3566 -•0000 E 1-3590 1-3586 -•0004 F 1-3606 G 1-3646 1-3646 •0000 H 1-3683 Hydrate of Phenyl. — Dale and Gladstone. B 1-5416 C 1-5433 1-5428 -•0005 D 1-5488 1-5495 + •0007 E 1-5564 1-5567 + •0003 F 1-5639 G 1-5763 1-5772 + •0009 H 1-5886 In both these media, of low dispersive and refractive power, the accordances of theory and observation are sufficiently close. 203 Oil of Lavender. — Powell. T>0 *• Observation. Theory. B 1-4641 C 1-4658 1-4632 -•0026 D 1-4660 1-4678 + •0018 E 1-4728 1-4726 -•0002 F 1-4760 G 1-4837 1-4848 + •0011 H 1-4930? Oil of Sandal- wood.— Powell. B 1-5034 C •5058 1-4988 -•0070 D •5091 1-5062 — •0029 E •5117 1-5102 -•0015 F •5151 G •5231 1-5271 + •0040 H •5398? Oil of Spikenard.— Powell. B 1-4732 C 1-4746 1-4744 -•0002 D 1-4783 1-4082 -•0001 E 1-4829 1-4826 -•0003 F 1-4868 G 1-4944 1-4945 + •0001 H 1-5009 Benzole . — Powell. B 1-4895 C •4961 1-4907 -•0054 D •4978 1-4965 -•0013 E •5041 1-5029 — •0012 F •5093 G •5206 1-5210 + •0004 H •5310 204 In oil of lavender and of sandal-wood there was some indistinct- ness in the line H which renders its index a little uncertain. It may be owing to this circumstance that the assumption of that index may have occasioned the discrepancy between theory and observation. In oil of spikenard the accordance is good. In benzole the discre- pancies are too great. Bisulphide of Carbon. — Dale and Gladstone. Ray. !*• Difference. Observation. Theory. B C D E F G H 1-6177 1-6209 •6303 •6434 •6554 •6799 •7035 1-6169 1-6251 1-6425 1-6807 -•0040 -•0052 -•0009 + •0108 Phosphorus dissolved in Bisulphide of Carbon. — Dale and Gladstone. B C D E F G H 1-9314 1-9298 1-9522 1-9726 2-0363 — •0005 -•0018 + •0002 1-9527 1-9744 1-9941 2-0361 2-0746 In the first of these media the differences are greater than can be fairly allowed to errors of observation. In the second case it is yet more clearly apparent that the theory is defective. The ray C was not observed ; but the theoretical index is evidently in error to a large amount, as it is even lower than that of B. The indices for D and C are perhaps within the limits of error : but that of E is too much in defect to be allowed. 205 December 22, 1859. Sir BENJAMIN C. BRODIE, Bart., President, in the Chair. Bennet Woodcroft, Esq., was admitted into the Society. The following communications were read : — I. "On the Electric Conducting Power of Alloys." By A. MATTHIESSEN, Pn.D. Communicated by Prof. WHEAT- STONE. Received November 17, 1859. (Abstract.) In this paper I have given the determinations of the electric con- ducting power of upwards of 200 alloys, and have found that the metals employed may be divided into two classes, viz. — A. Those metals which, when alloyed with each other, conduct electricity in the ratio of their relative volumes. B. Those metals which, when alloyed with one of class A, or with each other, do not conduct electricity in the ratio of their relative volumes, but always less. The alloys may be divided into three groups ; viz. — 1 . Those made of the metals of class A with each other. 2. Those made of the metals of class A with those of class B. 3. Those made of the metals of class B with each other. From the experiments described in the paper I have tried to deduce the nature of alloys, and have arrived at the following conclusions : — A. That most alloys are only a solution of one metal in the other ; for,— 1. On looking at the curves belonging to the different groups, we see that each group of alloys has a curve of a distinct and separate form. Thus for the first we have nearly straight lines ; for the second, the conducting power decreases always rapidly on the side of the metal belonging to class B, arid then turning, goes almost in a straight line to the metal belonging to class A j for the third group we find a rapid decrement on both sides of the curve, and the turning-points united by almost a straight line. 206 2. On examining that part of the curve where the rapid decrement takes place, we find that with the lead and tin alloys it generally requires twice as many volumes of the former as of the latter to reduce a metal of class B to a certain conducting power. 3. That the turning-points of these curves are not chemical com- binations we may assume from the fact that they only contain very small per-centages of the one metal. 4. That the alloys at the turning-points have their calculated specific gravities. 5. From the similarity of the curves of the conducting power of alloys, where we may assume we have only a solution of one metal in the other, we may always draw approximative^ the curve of the alloys of any two metals if we know to which class they belong. B. That some alloys are chemical combinations ; for — 1. At the turning-points of the curve we generally find contraction or expansion. 2. We have no regular form of curve, so that we cannot a priori approximatively draw it. 3. At the turning-points of the curve, the alloy retains large per- centages of each metal. 4. The appearance (crystalline form, &c.) of the alloys at these points is different from each other. C. That some alloys are only mechanical mixtures ; for example, bismuth-zinc, lead-zinc, some silver-copper alloys, &c. The question now arises, To what is the rapid decrement of the conducting power of the metals belonging to class B, when alloyed with other metals, due ? The only answer I can at present give to this question is, that most of their other physical properties are altered in a like manner ; for where we find no marked change in most of the physical pro- perties, as in group I, and in the second group on the one side of the curve, then we have nearly their calculated conducting powers. In the Appendix I have given some determinations of the con- ducting power of pure gold, which I find has a higher value than that generally quoted. In conclusion, I may take this opportunity of thanking Dr. M. Holzmann for the excellent manner in which he has carried out the greater part of the experiments. 207 II. " On the Specific Gravity of Alloys." By A. MATTHIESSEN, Ph.D. Communicated by Professor WHEATSTONE. Re- ceived November 17, 1859. This communication consists of a revised version of a Paper of the author, having the same title, which was read on the 19th May, and of which an abstract has been already given under that date (page 12). III. " On an extended Form of the Index Symbol in the Cal- culus of Operations." By WILLIAM SPOTTISWOODE, Esq., M.A., F.R.S. Received November 24, 1859. (Abstract.) In the case of two variables (the only one considered in the present paper), the term Index Symbol means the operation =x^-+ — dx dy The new symbol is = L+X!L dx dy The symbols X, Xl have the following meaning, dx dy £,_ d1 d1 dx dy where the accent indicates that in the combinations of #, *B»j the differentiations are to affect the subject of operation alone, and not x or y, so far as they appear explicit in the values of &, &r The first object of the paper is to develope the relations between the combinations of 88, X1 and y» Vi ; and it is found that »,••= V, «— 1 0 .. 0 , or = V! 0 .. 0 V V, I ;— 2 . . 0 V vx t-2 .. 0 V, V Vl " 0 V: V V, .. 0 V Vz V • • V, V V V .. v according as i is even or odd. 208 Again, — (rt, b, . . (V ViI«» (VV1 • • (an_i/3n_i) V Vxlan-i where (y Vi vl«2 &I X 1^ A) = (V Vi vl«2 / It is further shown that the effect of the operations v, vl on a given function, u=*Zaixn-iyi, may be represented by and the case of The value of is examined in detail. in terms of *, -— , *2 — , . . *t -r-, *2 — , . . are calculated, (1) when ax ax ay dy slt *2, . . are any linear functions of x, y, (2) when they are any functions whatever; and, in case (1), the effect of the above opera- tion on a given function is determined. IV. " Problem on the Divisibility of Numbers." By FRANCIS ELEFANTI, Esq. Communicated by ARTHUR CAYLEY, Esq. Received November 24, 1859. Problem. To find a proceeding by which the divisibility of a proposed integer N by 7 or 13, or by both 7 and 13, may be deter- mined through the same rule. Solution. We can designate the number N by abed . . . mn, so that (a) be the first or highest, and (n) the last or lowest digit in it, therefore we may put 209 1. Take the first digit, and having placed it below the fourth, make the subtraction in the usual way, thus : N'=bcde . . .mn — a 2. Take the first digit of N', and having placed it below the fourth, eifect the subtraction, thus : W=cde...mn -b 3. Continue in the same way till you have effected the subtrac- tion upon (ft), and you will have the rule : Is N'" "• = ... I'm'n' divisible by 7 or 9, or by 7 and 9 at the same time? then is the number N divisible too by 7 or 13, or by 7 and 13 at the same time. Ex. I. N =71491 N' = ^ = 1421 N"= ^1=420=7-60; therefore N is divisible by 7. Ex. II. N =246571 N'= 46] =46371 N"= 001 N"'= _g=325 = 52-13; the number N is divisible by 13. Ex. III. N= 1,1 83530803 1,825 8,243 2,350 3,4 8 8 4,850 8,463 455 = 57'13; the proposed number N is divisible both by 7 and by 13. 210 Ex. IV. N=7429 N'= 422=422=2-2il, — / the number N is divisible neither by 7 nor by 13. Remark. — The above proceeding is but the application of a general principle, inherent to our decadic system. The author is in possession of similar proceedings for all prime numbers up to 107 ; above that limit (except a few cases) the rules become more com- plicated, and lose the high value of easy application. Taking again N=abcde . . . mn, we have the following Table for operating by the different prime numbers up to 109 : — Divisors. Operation. 7,13 .................. d-a 17,59 .................. d-3a 19,53 .................. d—7a 23,43 .................. +• N. / Formula of Dr. Hofmann. Ethylene-diamine C4 H8 N2= H/ IN, 2 } (C4H4)") Diethylene-diamine . . C8 H10 N2= (C4 H4)" I N2. H2 J (C4H4)"] Triethylene-diamine . . Cla H12 N2= (C4 H4)" L N2. (c4H4yr 227 It was by careful examination of the physical properties of the bases under consideration, and more especially by the absence of simple equations capable of explaining the formation of the first and of the third terms of the series, that I had first been led to doubt the correctness of M. Cloez's formulae ; but I would not have expressed this doubt, if, on repeating the analysis of the first base, of formen- amine, the slightest doubt on the subject had remained in my mind. I did not at the time investigate the two other bases, and I limited myself to stating that the constitution of these bodies would probably be found analogous to that which I had experimentally established for the first term of the series. Let us now examine the objections which M. Cloe'z has brought forward against my argument. "According to the hypothesis of M. Hofmann," says he, " the action of ammonia on the chlorinated and brominated hydrocarbons cannot give rise to the formation of chloride or bromide of ammonium ; the reaction consists simply in a combination of the two substances, without the separation of a third compound: it is a case of symmorphosis or addition, (C4 H4) C12 + 2H3 N=(C4 H4)H4 N2, 2 HC1. Experiment proves, however, that the reaction involves the elimi^ nation of hydrochloric acid and the fixation of the elements of amidogen : apomorphosis and symmorphosis are accomplished side by side, as indicated by the following equation : — C4 H4 C12 + 2H3 N=(C4 H3)H2 N, HC1 + H3 N, HC1." M. Cloe'z would be perfectly right if during the reaction no other base were formed except the first one. But he forgets altogether that in the process under examination — exactly as in the mutual reaction between bromide of ethyl and ammonia — several other bases of more advanced substitution are produced. The equations which I give for the formation of these bodies likewise involve the elimi- nation of bromide of ammonium, and in fact of considerable quantities of this compound. 2(C4 H4)" Br2 + 4H3 N = (C4 H4)2" H2 N2, 2HBr + 2(H3 N, HBr). 3(C4 HJ" Br2 + 6H3 N=(C4 H4)3" N2, 2 HBr + 4 (H3 N, HBr). The bromide of ammonium then, which separates in considerable quantity in the action of dibromide of ethylene upon ammonia, be- VOL. x. R 228 longs to the second and third portions of the reaction ; it has nothing whatever to do with the formation of the first base. M. Cloez, as I have pointed out, does not admit the simple equation which I have given for the formation of this body ; he denies that it is simply formed by the union of the two compounds reacting upon each other. According to his opinion it is produced in a secondary re- action, occasioned by the intervention of heat. My experiments do not confirm this opinion. A mixture of dibromide of ethylene and alcoholic ammonia allowed to stand for some time at the ordinary temperature, deposited a quantity of crystals, from which I was en- abled to extract, without distillation, simply by successive crystal- lizations, absolutely pure salt of ethylene-diamine, as proved by the analysis of the bromide, the chloride, and the platinum-salt. In discussing the numbers which I have obtained in analysing the hydrate and the hydrochlorate of the first base, M. Cloez quotes the results on which he founds his own formula. A glance at these figures will show unmistakeably that they agree much better with my formula than with the one which he defends. The following are the analytical details of our analyses, together with the theo- retical values required by each formula : — Formula of Analysis of Formula of Analysis of M. Cloez. M. Cloez. Dr. Hofmann. Dr. Hofmann. Carbon 31'58 3M2 3076 30'67 Hydrogen .. 10-52 1277 12-82 12-97 Every experimentalist has incontestably the first right of inter- preting his analytical results ; knowing, as he does, his methods, he will do it generally much better than any other person. In the case before us, however, I believe very few chemists would have inter- preted the results of analysis as M. Cloez has done. As far as I am concerned, I would always prefer to admit having lost 0*2 per cent, of hydrogen, to calculating a formula requiring 2 "25 per cent, of hydrogen less than had been obtained by experiment. I would prefer this especially in analysing a substance like ethylene-diamine, attracting carbonic acid with the utmost avidity — a trace of which would very appreciably lower the experimental hydrogen — and con- taining so high a percentage of hydrogen, that the presence even of a small quantity of water would produce a somewhat similar effect. 229 The results which M. Cloez has obtained in the analysis of the hydrochlorate are not less in favour of my views. He finds 1'28 per cent, of hydrogen more than required by his formula, whilst ad- mitting my theory, he would not have lost more than 0*13 per cent. I have since examined several other salts of ethylene-diamine, and the results fully confirm the conclusions drawn from my former analyses. It would be useless to quote these additional experiments, but I will mention the characteristic numbers furnished by the ana- lysis of the anhydrous base, since the diminution of the equivalent exhibits in a more striking manner the differences between the theoretical values of the two formulae. Ethylene-diamine retains the water with the greatest energy, and it is in fact only by protracted contact with metallic sodium that it is possible to obtain this body in the anhydrous condition. I give the numbers obtained by com- bustion, side by side with the theoretical values of the two formulae : Analysis. 40-13 13-31 These numbers require no commentary. It is not, however, in the results of analysis that M. Cloez finds the chief support of his views ; he quotes an observation which at the first glance appears fatal to the diatomic notions. " But there is," continues M. Cloez, " a capital fact (un fait capital) which completely settles the question at issue : this is the. vapour-density of the free base" This density has been found by experiment to be 1'42. " The theoretical density calculated for my formula, referred to 4 volumes, is 1*315 ; the modified formula of M. Hofmann, likewise referred to 4 volumes, gives the theoretical density of 2' 699. " These results appear to me decisive, and I do not hesitate to maintain the formula of the new series of bases, of which I first pointed out the formation." I entirely agree with M. Cloez as to the importance of the deter- mination of the vapour-densities, but I certainly arrive at a very different interpretation of his result. R2 Carbon . . Formula of M. Cloez, C2H3N. ....41-37 Formula of Dr. Hofmann, C4 H8 N2. 40-00 Hydrogen ... 10-34 13-33 230 In repeating the experiment of this able chemist, I have arrived, as might have been expected, at exactly the same number. But this number refers to the hydrated base, and it is easily seen that the hydrated molecule, when in the state of vapour, must occupy 8 volumes. In calculating the theoretical density corresponding to the diatomic formula when referred to 8 volumes, we arrive at the number 1*35, which coincides in fact with the number obtained by experiment. It is obvious that under the influence of heat the hydrated base splits into anhydrous base (4 volumes) and water (4 volumes), and that, instead of taking the vapour-density of the intact hydrated molecule, M. Cloez has determined the density of a mixture of an- hydrous base and water, which on cooling combined again, repro- ducing the hydrated compound. And here I must recall the observa- tions of several chemists, especially those of M. Bineau, of M. Kekule, and of M. H. Saint-Claire Deville, each of whom has had the opportunity of explaining the anomalous vapour-densities in the transitory decomposition of the compounds submitted to experiment ; and I would quote particularly a note by Professor Kopp*, in which this distinguished physicist has treated the question of anomalous vapour- densities in a general manner. In the case before us, there is a very simple experiment, calculated to remove all hypothesis from the above explanation, — the determina- tion of the vapour-density of the anhydrous base. The experiment made with a substance the purity of which had previously been proved by analysis, led to the number 2*00, which indeed absolutely coincides with the theoretical density of the diatomic formula C4 H8Na referred to 4 volumes. This theoretical density is 2'07, whilst the formula of M. Cloez, likewise referred to 4 volumes, requires the theoretical density of TOO. The molecule of ethylene-diamine (formenamine) then, like those of all other well-examined organic compounds, corresponds to 4- volumes of vapour ; and the vapour-density of the base, far from militating against the molecular value which I assign to this body, furnishes on the contrary an additional and incontestable argument in its favour. * Ann. de Chem. et de Pharm. cv. 390. 231 The preceding remarks are, I hope, sufficient to establish the formulae of the diatomic ammonias upon a solid basis. I will there- fore only briefly allude to some results which I have obtained in studying the products of decomposition of ethylene-diamine, and which are not less characteristic. Submitted to the action of nitrous acid, this base is decomposed with evolution of nitrogen ; in the first stage of the reaction an indifferent crystalline body is produced, and the final result of the process is a large quantity of pure oxalic acid. The nitrogen evolved during the transformation is accompanied by a very volatile liquid, the odour of which is somewhat similar to that of aldehyde. At the time when I made these experiments I really believed the liquid to be aldehyde, but since I failed in obtaining the crystalline compound with ammonia and in transforming it into acetic acid, I abstained from mentioning this reaction in my note to the Royal Society. I have now scarcely a doubt that the volatile liquid was the oxide of ethylene, isomeric with aldehyde, since discovered by M. Wurtz. The transformation would be C4H8N2+2N03=4N + C4H402+4HO. In preparing the ethylene-diamine for my experiments, I obtained as a secondary product a small quantity of the second base, which M. Cloe'z has described as acetenamine, and for which I now propose the term diethylene-diamine. This base has exactly the same per- centage composition, whether viewed as a diamine or considered as the monatomic acetenamine of M. Cloe'z. The analysis of the base itself, and of some of its salts, fully confirms the results obtained by that chemist. Bat this base is no primary monamine ; it does not contain the radical acetyl, C4 H3, as supposed by M. Cloe'z ; it is a secondary diamine containing two molecules of ethylene. Aceten- amine, as conceived by M. Cloe'z, should be formed by the action of chloride, bromide, and iodide of vinyl (C4H3C1, C4 H3 Br, C4 H3 1) upon ammonia. These reactions do not furnish a trace of the base in question. But there is a more conclusive proof of the diatomic nature of this body, the evidence of which will not be contested by M. Cloe'z, — this is the determination of the vapour-density. Experi- ment gave the number 27. The diatomic formula, C8 H10 N2, referred to 4 volumes of vapour, requires 2' 9. According to the monatomic view, a vapour-density of 1*45 should have been found. 232 The preceding experiments, although fixing in a satisfactory manner the composition and the equivalents of the two diammonias, do not unveil their molecular constitution — their degree of substi- tution. I have endeavoured to solve this problem by submitting them to the action of iodide of ethyl, a process which I have first used for similar purposes, and which has since become of general application. This process, moreover, could not fail to furnish a final decision between the two theories. In considering with M. Cloe'z the two bases as primary monamines belonging respectively to the formic and to the acetic groups, C2H) ' C4H3] H IN H IN, H J H J it is evident that each of them must be capable of absorbing success- ively 1, 2, or 3 equivalents of ethyl, and of yielding three ethylated bases, two volatile, and one fixed. On the contrary, if the bases were products of the successive substitution of the same molecule for the hydrogen of two equivalents of ammonia, if they were respectively a primary and a secondary diamine, (C4HJ") (C4H4)" H, lN2, (CJIJ- H2 J H, the first of the two must likewise give rise to the formation of three bases, whilst the second one would produce only two. Experiment has verified this latter anticipation. In submitting ethylene-diamine to the alternate action of iodide of ethyl and oxide of silver, I have succeeded in obtaining two volatile ethylated bases, and a third one, which is fixed. These compounds are well defined ; their composition was established by the analysis of their iodides or their platinum-salts. Represented as salts, these bases contain — Salt of ethylene-diammonium [(C4 HJ" H6 N2]" I2, Salt of diethylated ethylene-diammonium . . [(C4 H4)'f (C4 H5)2 H4 N2J" I2. Salt of tetrethylated ethylene-diammonium [(04 H4)" (C4 H5)4 H2 Nj" I2. Salt of hexethylated ethylene-diammonium [(C4 H J" (C4 H5)6 N J" I2. 233 On repeating the same experiments with diethylene-diamine, per- fectly analogous phenomena were observed, but the reaction yielded only one volatile base, which was immediately converted into a fixed base. Analysed in a similar manner, and represented as salts, these bases exhibit the following composition : — Salt of diethylene-diammonium [(C4 HJ"2 H4 Na]" Ia. Salt of diethylated diethylene-diammonium [(C4 H4)"2 (C4 H5)2 H2 N2]" I2. Salt of tetrethylated diethylene-diammonium [(C4 H4)"2 (C4 H5)4 N2]" I2. The same result is accomplished, but in a shorter and more elegant manner, by substituting iodide of methyl for its ethylated homologue. Already, at an earlier period, I have shown that iodide of methyl has a remarkable tendency to yield the last product of substitution. Thus, on treating iodide of methyl with ammonia, the iodide of tetramethylammonium is alone obtained, together with a very large proportion of iodide of ammonium. The action of iodide of methyl with the ethylenated bases is perfectly analogous. The last product of substitution is formed at once in notable quantity, and may be purified by a simple crystallization. I have obtained in this manner, without being embarrassed by the intermediate compounds, the iodide of hexmethylated ethylene-diammonium and of tetramethylated diethylene-diammonium . These results require no further explanation. In the present state of science we rely upon a certain number of considerations which guide us in the construction of a chemical formula. These are, — the study of the origin of a body ; analysis ; observation of the physical properties, and especially of the boiling- point ; the determination of the vapour-density ; and lastly, the exa- mination of its metamorphoses. I have endeavoured to look at the question under discussion from these several points of view ; experi- ment has given invariably the same reply. It follows from this controversy that the diatomic alcohols imitate the monatomic alcohols in their deportment with ammonia. Ethyl alcohol produces, as is well known, three ethylated ammonias, the molecules of which occupy 4 volumes of vapour. Ethylamine H I N=4 volumes. 234 C4H Diethylamine C4 H5 >N = 4 volumes. H Triethylamine C4 H5 >N = 4 volumes. C.H.J In a similar manner we find that glycol, the diatomic alcohol of ethylene, the discovery of which we owe to the remarkable labours of M. Wurtz, gives rise to three diatomic bases, corresponding to 2 molecules of ammonia, and representing likewise 4 volumes of vapour. (C4H4)^ Ethvlene-diamine H2 v\ =4 volumes. H2 v\ H2 J Diethylene-diamine (C4 H.)" VN =4 volumes. H2 J (C4H4)'r\ Triethylene-diamine (C4H4)" >N2=4 volumes. (C,HJ»J The two first terms of this series are the bases which M. Cloe'z discovered about six years ago, but the true nature of which he failed to recognize. To complete the series, it remains only to examine the third volatile base and the oxide of tetrethylene-diammonium. The observations which I have the honour of submitting to the Royal Society coincide in every point with the first note upon this subject which I presented nearly two years ago. I have simply carried out somewhat more in detail the sketch traced in my former communication. In conclusion I may state a fact which has also been observed by M. Cloe'z, viz. that the action of dibromide of ethylene upon ammonia gives rise to the formation of bases not directly belonging to the series which we have discussed. In searching for the method of purifying the ethylene bases, I have been obliged to examine also the terms of the other group ; but since these substances do not necessarily belong to this part of the inquiry, I omit for the present to enter more fully into their examination. 235 II. " On the Forces that produce the great Currents of the Air and of the Ocean." By THOMAS HOPKINS, Esq. Commu- nicated by J. P. JOULE, LL.D. Received December 2, 1859. (Abstract.) In this paper the writer pointed oat the fact that we have at present no satisfactory evidence in books of what are the immediate causes of the great currents of the air and of the ocean ; and he maintained that the liberated heat of condensing vapour is the cause of these currents. He then proceeded to show that all the great winds terminate in comparative vacua created in particular localities where much vapour has been condensed ; and contended that such vacua enable and cause heavier air to press and flow towards the parts which have been rendered light, — to re-establish the equilibrium of atmospheric pressure, — thus making heat the disturbing power in the aerial ocean, and leaving gravitation to act to restore an equilibrium. The great primary currents of the ocean were also described, and they were shown to be so situated as to be under the influence of the principal winds, which, in their passage over the waters, press on them, and force them forward as currents. These currents were maintained to be of a velocity, extent, and depth proportioned to the strength and continuity of the wind, showing that the pressure of the air on the water, whilst moving over it, is capable of producing the movement which takes place. When, how- ever, water is put into motion, it may be obstructed by land, and turned from its direct course, and in that way be made to form secondary currents. But it was contended that heat of vapour, set free in the atmosphere, is the force which disturbs the equilibrium of pressure, and either directly or indirectly produces all the great continuous movements that take place both in the atmosphere and the ocean. III. " On the Movements of Liquid Metals and Electrolytes in the Voltaic Circuit." By GEORGE GORE, Esq. Commu- nicated by Professor TYNDALL. Received December 1, 1859. 1 . It has long been known that when a globule or layer of pure VOL. x. s 236 and clear mercury is placed upon a smooth non-metallic surface, a watch-glass for example, and covered to a small depth with a watery electrolyte, sulphuric acid in particular, and two terminal platinum wires from a voltaic battery are dipped into the electrolyte, one on each side of the globule, the mercury makes a movement towards the negative wire, and a rapid and continuous stream of the super- natant liquid flows from the negative to the positive electrode over the surface of the mercury, and back again by the sides of the con- taining vessel. Also that when a small drop of a watery electrolyte, especially sulphuric acid, is placed upon the surface of pure and dry mercury, the latter connected with the negative pole of a battery, and a platinum wire from the other pole momentarily immersed in the electrolyte, the drop of liquid is suddenly repelled and spreads over the surface of the mercury. 2. These phenomena have been examined by Herschel*, Erman, H. Davy, Runge, Pfaff, and others f, and some of the results have been recorded in the 1st volume of 'Gmelin's Handbook of Che- mistry,' page 486 (published by the Cavendish Society) ; but no definite cause of the movements seems to have been discovered. Herschel has, however, shown that the continuous movement of the supernatant liquid is unaffected by the approach of strong magnets, and that it is influenced by the chemical nature of the electrolyte ; also that its direction is notably influenced by the presence of vari- ous metallic impurities in the mercury. 3. Being desirous of ascertaining the conditions under which the movements are produced, the relations of the phenomena to ordinary and recognized actions, and the more immediate cause or causes of the movements, Ihave undertaken the folio wing experimental investigation. 4. In describing the experiments I shall have frequent occasion to speak of the continuous flow of the electrolyte, and of the sudden re- pulsion of drops of liquid already mentioned, and shall therefore speak of the former as the continuous action or movement, and of the latter as the sudden or momentary one. Also in speaking of the conti- nuous motion, I shall call it positive flow or movement when the super- * " On certain Motions produced in Fluid Conductors when transmitting the Electric Current," Phil. Trans. 1824. t Draper has recorded some experiments of a similar kind. — Philosophical Magazine, S. 3. vol. xxvi. p. 185. 237 natant liquid proceeds from the positive wire towards the negative one, and negative flow, &c. when it passes in the opposite direction. 5. The usual method of manipulation I have adopted has been to take a watch-glass of about 2 inches diameter and place in it by means of a small gutta-percha spoon capable of containing from 20 to 50 grains of mercury, a globule of that metal of about 30 grains weight, adding sufficient of the electrolyte to just cover or nearly cover the globule of metal, and sifting a few particles of finely powdered char- coal or asphaltum upon the surface of the liquid, to facilitate obser- vation of the movements ; next, using a Smee's battery of 22 pairs of plates 4 inches deep and 2|- inches wide with terminal platinum wires, charged with one measure of oil of vitriol and 15 measures of water, I place the end of the negative wire in the liquid about ^th of an inch from the mercury, and then carefully immerse the end of the positive wire in the liquid on the opposite side of the globule, at a greater distance from the mercury than the negative wire in the case of an alkaline solution, and at a less distance in the case of an acid one, in order to prevent the mercury from touching the electrodes by its movement and thus vitiating the first and purest result. A polished oval space 2 inches long, fths of an inch wide, and -f ths of an inch deep, with a curved bottom, formed in a thick plate of glass and substituted for the watch-glass, did not admit of such satisfactory freedom of motion. In doubtful cases of movement, a small porcelain boat, such as is used in organic chemical analysis, was sometimes employed instead of the watch-glass ; and in certain special experi- ments a V-tube was employed. In nearly all cases the mercury gra- dually became impure, and therefore fresh mercury was taken for each experiment. A. Conditions of the Movements. 6. Two substances are always required in these experiments, with one alone the movements never occur. 7. To determine whether both the substances must be in a liquid state: — 1st. A portion of mercury in a watch-glass was connected with the negative pole of a battery and covered with a flat piece of platinum foil ; a drop of solution of sulphate of potash was placed upon the foil and the end of the positive wire dipped into it. No move- ment, either sudden or continuous, of the solution or mercury took place. On substituting for the foil a circular piece of filtering paper varnished all round its edge and covered with several drops of the s 2 238 solution of sulphate of potash, the sudden repulsions were produced readily, but were much less powerful than when the liquid was placed alone upon the mercury. 2nd. Two circular clean spaces, \ an inch wide, were scraped with a knife upon a horizontal plate of zinc ; one of them was amalgamated with mercury and left covered with a very shallow layer of that metal, the other was also amalgamated, but the excess of mercury was wiped off ; each of the spots was now covered with a shallow layer of a weak solution of sulphate of alumina, the zinc plate connected with the negative plate of the battery, and the end of the positive platinum wire dipped in succession into the super- natant portions of liquid ; the solution above the thin layer of liquid mercury was powerfully repelled on making the contact, whilst that upon the other spot was unaffected. Similar results were obtained with a solution of caustic potash, also with a plate of tin. 3rd. A portion of Newton's fusible alloy was melted under a layer -J-th of an inch deep of a solution of chloride of zinc, and the ends of the platinum wires from the battery immersed in the supernatant liquid until the alloy cooled and solidified ; the zinc solution flowed from the negative towards the positive wire as long as the surface of the alloy remained in the liquid state, and ceased to flow immediately the surface of the metal solidified. Also a drop of a strong solution of caustic potash placed upon the melted fusible alloy, the latter con- nected with the negative pole and the former with the positive pole, exhibited the usual momentary repulsions as long as the surface of the alloy remained fluid. I therefore conclude that both the substances must be in a liquid state. 8. To ascertain whether both the substances must be conductors of electricity : — 1 st. I formed melted globules of phosphorus in warm oil of vitriol, also in a hot mixture of one measure of distilled water and two measures of oil of vitriolj and immersed the wires in the usual manner, but no motion of the liquid occurred. 2nd. No movements were obtained with a globule of bromine under warm oil of vitriol ; a large globule of bromine was placed in a porcelain boat, and dilute sul- phuric acid added until the bromine was partly covered ; the wires were then applied, but no movements took place. Also the addition of sulphur and of selenium to the bromine did not ensure a different effect. 3rd. With a large globule of selenium under fused chloride of zinc no motion was obtained. 4th. I made similar experiments with globules of chloroform, also of bisulphide of carbon in dilute sul- 239 phuric acid, but obtained no movements. 5th. No movements took place with globules of chloroform in a solution of caustic potash or of sulphate of alumina. 9. To determine whether one of the substances must be metallic : — 1st. A definite layer of oil of vitriol was placed beneath a layer of distilled water weakly acidulated with sulphuric acid, and the terminal wires immersed in the upper liquid ; no movements occurred at the boundary line of the two liquids. 2nd. A dense solution of cyanide of potassium was placed in a small glass beaker, a few particles of charcoal were sifted upon its surface, and a layer of aqueous ammonia j an inch deep carefully poured upon it. A vertical diaphragm of thin sheet gutta percha was then fixed so as completely to divide the upper liquid into two equal parts ; the vessel was placed in a strong light, and two horizontal platinum wire electrodes from 66 pairs of freshly- charged Smee's batteries immersed |-th of an inch deep in the liquid ammonia on each side of the diaphragm. A copious current of electricity circulated, but no movements of the liquids at their mutual boundary line could be detected. A small globule of mercury placed in the lower liquid at once produced evident signs of motion. One of the substances must therefore be a metallic conductor of electricity. 10. To ascertain whether the capability of producing these move- ments was a general property of metals and alloys when in the liquid state : — 1st. Bismuth was fused beneath a layer of chloride of zinc ; tin was also melted under a similar layer, and the terminal wires im- mersed in the supernatant liquid ; a steady negative flow occurred in each case. 2nd. Cadmium was similarly treated under fused cyanide of potassium, and a positive flow obtained. 3rd. Cadmium, lead, Britannia- metal, and fusible metal were melted separately, small pieces of cyanide of potassium placed upon them and melted, the metal con- nected with the negative platinum wire, and the positive wire dipped into the melted cyanide ; positive repulsions took place with each metal on making contact. I conclude from these experiments that the power of rotating under the influence of an electrolytic current is a general property of metals and alloys when in a liquid state. 1 1 . That the mass or body of the metal is not essential to the production of the movements, is evident from the fact that the move- ments have been readily obtained with thin layers of mercury upoa amalgamated zinc (7) and copper plates. 240 12. I have endeavoured to obtain the movements without the presence of an electrolyte, by passing an electric current through a small globule of zinc fused upon the surface of bismuth, but the ready mingling of the melted metals, and their rapid oxidation, pre- vented a reliable experiment being made. 13. It has already been shown, in the instances of fused salts upon melted metals (10), that the presence of water is not a necessary condition of the phenomena. 14. The power of producing the movements is a general property of electrolytes as well as of liquid metals ; I have experimentally found it in the following classes of substances : — organic and in- organic acids ; water ; aqueous solutions of caustic alkalies* ; alkaline carbonates, bicarbonates, borates, hypophosphites, phosphates, sul- phides, hyposulphites, sulphites, sulphates, bisulphates, iodides, bro- mides, chlorides, chlorates, nitrates, and silicates ; salts of alkaline earths and of alumina ; salts of tungsten, molybdenum, chromium, uranium, manganese, arsenic, and of the malleable heavy metals ; also with fused salts, aqueous solutions of organic salts, and solutions of salts in alcohol. The salts of tungsten, molybdenum, chromium, uranium, and manganese, generally gave the weakest and most variable results ; whilst sulphuric acid and solutions of alkaline cyanides yielded very strong and definite movements. In feeble cases of motion the globule of mercury should be placed in a narrow porcelain boat, and a strong solution of the substance added until the metal is only covered at its sides with the liquid ; and for still greater sensitiveness, the experiment of placing a drop of the liquid upon the surface of the mercury should be adopted. 15. The mass or body of the liquid is not essential to the move- ments ; mere films of solution adhering to the under surface of a circular disc of brass, brought into contact with mercury under the influence of a voltaic current, exhibited the phenomenon readily. 16. To ascertain whether the current of electricity must pass from the electrolyte into the metal, or vice versa : — 1st. A layer of mercury was placed in a narrow glass beaker, upon it a shallow layer of chlo- * Herschel found no movements with solutions of caustic alkalies ( Vide Gmeliu's Handbook, vol. i. page 490) ; I have readily obtained them with pure mercury in solutions of pure alkalies by using strong solutions and a powerful electric current, and placing only a small quantity of the liquid above the mercury so as to pro- duce the maximum of effect. Alkaline solutions in general act much more feebly han acids. 241 reform, and above this, in one instance a dilute solution of sulphate of alumina ; and in the other instance, asolution of caustic potash, and the wires from the battery dipped into the upper liquid ; no movements at either of the contiguous surfaces occurred, 2nd. Similar experiments were made, substituting in one case a definite layer of oil of vitriol with a very dilute solution of sulphuric acid above it, and in the other case a dense solution of chloride of zinc with a very dilute solution of the same salt above it, for the chloro- form and its supernatant liquid ; in each case only feeble movements in the usual direction at the surface of the mercury occurred ; the weakness of the movements was probably a consequence of the in- creased distance of the electrodes from the mercury. 3rd. The lower part of a V-tube of half an inch bore was just filled with mercury, and a small quantity of solution of cyanide of potassium poured into each leg ; on dipping the polar wires, one into the solution of each leg, the saline liquid rapidly flowed from the positive to the negative leg until it was 1^ inch high in that limb. From these experiments I infer that the electric current must pass from the electrolyte into the metal, or vice versa, and that the continuous movements are not results of any power radiating from the electrodes. 1 7. It is not essential that the electric current should pass both into and out of the metallic globule by the electrolyte ; with a glo- bule of mercury in rather strong sulphuric acid and either of the polar wires immersed in the acid, the other wire being in contact with mercury, the movements occurred : also with the negative wire touching a globule of mercury in a solution either of cyanide of potassium or strong caustic potash and the positive wire in the liquid, movements were readily obtained. 18. To ascertain whether the electrodes were essential to the movements, I placed a large globule of mercury in the middle part of a slightly bent horizontal glass tube, 20 inches long and \ an inch diameter, then filled the tube with a strong solution of cyanide of potassium, and immersed the polar wires a short di- stance in the liquid at each end; a strong positive flow of the solution over the surface of the mercury occurred, but no movements took place at the surfaces of the electrodes, except such as were produced by the evolution of gas. The electrodes evidently operate merely as conductors of the electricity, and are not, in an abstract sense, at all connected with the movements. 242 19. Herschel has shown that the approach of strong magnets has no effect on the motions (vide Gmelin's Handbook, vol. i. p. 490), and I have also found that the movements are not electro-magnetic. A watch-glass — containing in one instance a solution of cyanide of potassium, in a second instance a solution of hydrochlorate of am- monia, and in a third instance oil of vitriol, — was placed upon one of the poles of a vertical horse-shoe electro-magnet capable of sustaining about 100 pounds, and the end of a large soft-iron armature which rested upon the other pole brought near the glass. The polar wires from the Smee's battery of twenty-two pairs were now immersed in the electrolyte on each side of the globule, and the magnet con- nected with a separate battery of large surface. The direction of flow of the electrolyte was instantly changed to a circular one all round the glass, and was reversed by reversing the polarity of the magnet. In each case the direction of motion of the electrolyte corresponded with that of the electric current beneath it ; i. e. with a south pole beneath, the liquid moved in the same direction as the hands of a watch ; — this circular motion was evidently a case of ordinary electro- magnetic action, as it occurred equally well without the presence of a liquid metal in the electrolyte. No real connexion of the mag- netism with the movements under investigation was detected. 20. To ascertain whether the movements varied with the quantity of the electric current, I prepared a single series of sixty-six pairs of Srnee's batteries, forty of which were charged with spring- water, and the remainder with a mixture of one measure of sulphuric acid and fifteen measures of water. The movements obtained on applying the current from the whole series to very dilute sulphuric acid con- taining a globule of mercury, were much more feeble and the amount of electrolysis much less than when the current from the twenty-six strongly-charged pairs alone was applied. On substituting distilled water for the dilute acid, the movements were stronger and the electrolysis greater with the whole series than with the twenty-six pairs. In all cases the movements appear to be dependent upon the quantity of electricity circulating. 21. It is highly probable, from the experiments just described, that the movements are intimately dependent upon electro-chemical action occurring at the surface of the liquid metal, especially as the amount of motion varies with the quantity of electricity which passes from the electrolyte into the metal, or vice versd ; and it would be very 243 desirable to obtain a negative proof of this by an experiment with a globule of one liquid metal in a bath of some other liquid metal, as already attempted (12). 22. With every liquid yet examined the movement of the liquid has invariably been attended by a simultaneous movement of the fluid metal ; and the greater the movement of the liquid the greater was the movement of the metal, from which I infer that the move- ments of the two substances are mutually dependent. 23. The results in general indicate that the sudden movements are of the same general character as the continuous ones, the effect in the former case being heightened by the concentration of the electric force within a small compass, together with the additional electric energy always displayed at the moment of making contact with a battery. 24. The movements require for their production two substances (6) ; both these substances must be in a liquid state (7), and be conductors of electricity (8) ; one of them must be a metal or a metallic alloy (9) ; any metal or alloy will do (10), and only a mere film of it is essential (11); the other must be an electrolyte, and need not contain water (13) : any electrolyte will do (14), and only a thin layer of it is requisite (15) : the electric current must pass from the electrolyte into the metal, or vice versd (16), but need not pass both into and out of it by the electrolyte (17); the electrodes are not essential (18) ; the movements are not electro-magnetic (19), they are dependent upon the quantity of the electric current (20), and are intimately connected with electro-chemical action (21) ; the movements of the metal and electrolyte are mutually dependent (22), and the momentary movements are of the same nature as the con- tinuous ones (23). 25. The pure or abstract conditions of the production of the phe- nomena are, — a liquid metal (or alloy) in contact with a liquid elec- trolyte, and a quantity current of electricity passing between them. B. Conditions of the continuance of the Movements. 26. With regard to the continuance of the movements: — 1st. In some cases the metal becomes covered with an insoluble film, produced by ordinary chemical action of the liquid, which prevents the continuance of the action ; this occurs particularly with mercury in strong solutions of sulphides, iodides, bromides, and chlorides. 244 2nd. If the positive wire is connected with the mercury and the negative wire with the liquid previous to placing both the wires in the electrolyte, films are in nearly all cases instantly produced (but not with strong sulphuric acid) and interfere with further action ; films are also frequently produced by a similar cause upon the end of the mercury nearest to the negative wire when both the wires are in the solution, and in many such cases the mercury creeps in a pecu- liar serpent-like form beneath the film towards the negative wire. 3rd. In many instances the metallic globule becomes of a pasty consistence by absorbing substances deposited upon its surface by electrolysis, and the motion declines ; this takes place particularly with mercury in solutions of salts of ammonia, baryta, strontia, magnesia, and lime, but most with those of magnesia and lime ; and it occurs very rapidly if, instead of placing both the polar wires in the electrolyte, the negative wire is immersed in the globule of mercury. It is evident from these facts, that it is essential to the continuance of the movements, that the particles composing the sur- face of the metallic globule should retain a sufficient degree of mo- bility to admit of free motion. 27« The best method of obtaining a continuous movement is to place a globule of pure mercury in a watch-glass, barely cover it with dilute sulphuric (or nitric) acid, connect it with the negative platinum wire and the liquid with the positive platinum wire of a battery of sufficient power to produce a moderate flow without over- heating the liquid : ten small Smee's batteries are sufficient. By this means I have obtained undiminished motion for upwards of six hours. C. Conditions of the direction of the Movements. 28. In speaking of the direction of the movements, I always mean those of the supernatant liquid, unless otherwise stated, because the true movements of the mercury are generally less easily detected than those of the electrolyte : the movements of the liquid are best observed by means of charcoal or asphaltum (5), and those of the mercury by the aid of a few parallel scratches upon the under sur- face of the watch-glass. 29. The directions of flow of the metal and liquid are intimately de- pendent upon each other, for in every instance the metal moves in an opposite direction to the electrolyte (see also 22) ; and in those cases 245 where two opposite flows of the liquid towards the centre of the vessel occur (as with a solution of sulphate of potash), the globule of mercury is elongated at both ends into a pointed shape, and its two ends point toward the two electrodes, its largest diameter being directly under the point of meeting of the flows of the solution, and its acutest apex under the strongest flow. The relation between the metal and liquid is apparently of a dual or polar character, the move- ments of the two bodies being always opposite and equal. This mutual dependence of the motions explains the necessity of both the substances being in a liquid state (7). 30. With regard to the direction of the flows, there are three cases to be distinguished: — 1st. The movements obtained by im- mersing the negative wire in the metal and the positive one in the electrolyte. 2nd. Those obtained whilst the positive wire is in the globule and the negative one in the electrolyte. 3rd. Those pro- duced by immersing both the wires in the supernatant liquid with the globule between them. 31. Upwards of 150 different liquids, including organic and in- organic acids, alkalies, salts of alkalies, earths and heavy metals, also organic salts, were examined by the first of these methods, and in almost every instance the flow of the supernatant liquid was positive, the clearest exception being with a solution of persulphate of iron. With concentrated sulphuric acid the motion (if any) was very feeble, but with diluted acid of various degrees of dilution it was strongly positive. The flow of the liquid declined quickly with solutions which contained an alkali-metal, apparently in consequence of the mercury becoming less mobile (?) by absorption of that metal ; but with dilute acids it continued a long time ; with very dilute nitric acid, in one experiment the movement was sustained with scarcely any diminution during 2| hours ; and with dilute sulphuric acid, in a second experiment it continued 6^ hours, and did not then appear to slacken : the battery employed hi this experiment con- sisted of ten small Smee's elements. A globule of strong sul- phuric acid was placed upon a surface of mercury, the latter connected with the negative pole, and the end of the positive wire dipped into the acid ; much gas was evolved from the anode, and the liquid was not repelled on making contact, but collected in a heap around the wire ; — a globule of solution of caustic potash 246 similarly treated exhibited repulsion on making contact. It is evident from these uniform results that the direction of flow obtained by immersing the positive wire in the electrolyte and the negative one in the mercury is almost uniformly positive. 32. The movements obtained by this method are not produced by the act of deposited substances dissolving in the mercury, for they occur equally well whether hydrogen gas is set free and escapes or alkali-metal is deposited and dissolves in the mercury, until in the latter case the diminished mobility of the globule interferes with the result. 33. Considerable difficulty was experienced in examining liquids by the second method, in consequence of the rapid and in many cases instantaneous oxidation or filming of the metallic globule ; but by using very dilute liquids and immersing the negative wire from seventy-two small Smee's elements during only a moment at a time, this difficulty was in most cases sufficiently overcome to allow di- stinct starts of the mercury to occur in the particular direction beneath its film, and thus to indicate an opposite motion of the supernatant liquid, although in nearly all cases the movement of the electrolyte itself could not be detected. Upwards of 100 liquids, consisting of organic and inorganic compounds — acid, alkaline, and neutral— were examined, and in more than three-fourths of them di- stinct movements of the metal were obtained, which were in every instance in a positive direction, thus indicating a negative flow of the electrolyte. In some liquids, viz. oil of vitriol, moderately di- lute nitric acid, strong solutions of sulphate of ammonia, iodide of ammonium, and sulphite of potash, very dilute solutions of bisul- phate of potash, iodide of potassium, nitrate of cobalt, hydro- cyanic acid, cyanide of potassium, and acetic acid, — visible move- ments of the liquid itself in a negative direction were also ob- tained. The movements of the liquid and of the metal very quickly ceased. These experiments show that the direction of flow ob- tained by placing the positive wire in the metal and the negative wire in the electrolyte is always negative. 34. The movements obtained both by methods 1 and 2 appear to be produced by a mutual attraction of the liquid and metal ; in the former case the mercury attracts an electro-positive element of the liquid (hydrogen or an alkali-metal), and produces a positive flow ; 247 and in the latter case it attracts an electro-negative element (generally oxygen), and produces a negative flow. 35. Herschel found by the third method of operating, that with pure mercury in acids and saline liquids the flow was negative, and was weaker as the base was stronger, and more rapid as the acid was stronger and more concentrated ; and that in solutions of nitrates two opposite flows occurred, one from each wire (vide Gmelin's Handbook, i. 490). I have found by an examination of pure mercury in various liquids the results exhibited in the following Table. The arrows indicate the direction of flow of the liquid, -j- being po- sitive and -j- negative ; and the numbers affixed to them afford a rough approximation of the velocity or magnitude of the movements. The battery employed consisted of twenty-two small Smee's elements. The substances were dissolved in water, and the solutions were of mode- rate strength unless otherwise stated. Manifestly impure substances were rejected, and fresh mercury was taken for each experiment. The results obtained were in many cases verified several times : — . -*• faint Distilled Water Boracic Acid Phosphoric Acid Strong Sulphuric Acid. . . Strong Sulphuric ~| Acid 1 measure I Water 5 „ j Strong Sulphuric "1 Acid 1 measure j. Water 15 „ J Strong Hydriodic "J Acid 1 measure L Water 15 „ J Hydrobromic Acid, very dilute Strong Hydrochloric "J Acid 1 measure L Water 5 „ j Strong Hydrochloric 1 Acid 1 measure I Water 15 „ j Perchloric Acid, very dilute Strong Hydrofluoric Acid 2 -j-4 H-4 Strong Hydrofluoric ~\ Acid 1 measure , Water 5 „ j Strong Nitric Acid, ~| 1 measure 1 Water 1 „ J Strong Nitric Acid, "1 1 measure I Water 5 „ J Strong Nitric Acid, ~| 1 measure I Water 15 „ J Aqueous Ammonia, strong Sesquicarbonate of Am- monia Phosphate of Ammonia . Sulphide of Ammo- ~\ nium, 1 measure" Water 15 „ J Sulphate of Ammonia . . . Hydrochlorate of Am- monia Nitrate of Ammonia Caustic Potash . . . 248 Carbonate of Potash ... -+ l +- ° Bicarbonate of Potash . . . H- 4 -i- 2 Sulphide of Potassium, dilute Sulphite of Potash -+ 2 Sulphate of Potash -}• 3 Bisulphate of Potash ...-»• 3 Iodide of Potassium ... H- 3 Bromide of Potassium. . . -}- 2 Chloride of Potassium ... -i- 4 Chlorate of Potash -}• 3 Nitrate of Potash n-3 Caustic Soda Carbonate of Soda -f- * Bicarbonate of Soda -}• 2 Biborate of Soda Diphosphate of Soda ... n-24 Sulphide of Sodium, dilute Hyposulphite of Soda ... -+ £ Sulphite of Soda Sulphate of Soda -+4 and then -f 4 Chloride of Sodium -j- 4 Nitrate of Soda -+3 Phosphate of Soda and Ammonia -*4 Baryta Water Carbonate of Baryta ... -f- 2 Chloride of Barium H- 2 Nitrate of Baryta -f- 3 Strontia Water Chloride of Strontium ... -+ 2 Nitrate of Strontia -+ Sulphate of Magnesia ... H- 3 Chloride of Magnesium, Chloride of Magnesium, Nitrate of Magnesia, strong Nitrate of Magnesia, Lime Water Sulphate of Lime Chloride of Calcium . . . Chloride of Calcium in Alcohol Nitrate of Lime Sulphate of Alumina . . . Potash Alum Hydrofluosilicic Acid . . . Silicate of Potash Molybdate of Ammonia . Chloride of Chromium, very weak Monochromate of Potash Nitrate of Uranium Sulphate of Manganese . Arsenic Acid Arseniate of Ammonia. . . Fluoride of Antimony. . . Antimoniate of Potash. . . Nitrate of Bismuth Sulphate of Zinc Iodide of Zinc, strong . . . Nitrate of Zinc Iodide of Cadmium Iodide of Tin, strong . . . Nitrate of Lead Protosulphate of Iron . . . Persulphate of Iron Chloride of Cobalt, weak Nitrate of Cobalt Sulphate of Nickel Nitrate of Nickel Sulphate of Copper, weak Chloride of Copper, very weak Nitrate of Copper Nitrate of Mercury Strong Aqueous Hydro- cyanic Acid Strong Aqueous Hy- drocyanic Acid, 4 measures Aqueous Ammonia, 1 measure Cyanide of Potassium . . . -»-3 H-4 H-4 249 Strong Aqueous Hy- \ drocyanic Acid, 5 measures V Caustic Soda Solution, I 1 measure / Cyanide of Mercury H- faint Ferrocyanide of Po- tassium Sulphocyanide of Po- tassium -+1 Oxalic Acid -*• 2 Oxalate of Ammonia ... H- 3 Acid Oxalate of Potash ... -+ 3 Neutral Oxalate of Potash -+ 4 Formic Acid -+5 Acetic Acid -t-3 Acetate of Potash -+s Acetate of Soda n-3 Acetate of Baryta n-2 Acetate of Uranium -f faint Acetate of Zinc -j-4 Acetate of Lead -* 1 Acetate of Copper H- l Tartaric Acid -f 5 Monotartrate of Potash . -}- 3 Bitartrate of Potash -+• 5 Bitartrate of Soda -*• 3 Tartrate of Potash and Soda -+3 Tartrate of Potash and Antimony _$. 3 Citric Acid -i-4 Succinic Acid -»- 4 Gallic Acid n-2 Pyrogallic Acid ~+ 4 Carbazotic Acid -»-4 Benzoic Acid. . . . . H- 2 Numerous interesting phenomena of motion and of colour, especially with solutions of salts of the earth-metals and with metallic iodides, were observed during the examination. 36. On examining these numerous results we find : — 1st. That all alkalies and some alkaline salts produce a positive flow only. 2nd. That some alkaline and many neutral salts produce both positive and negative flows. 3rd. That some neutral and many acid salts, and nearly all acids, both organic and inorganic, produce a negative flow only. The stronger influence of acids, compared to that of alkalies (14, Note) in the production of these movements, is pro- bably the reason why various salts of alkaline reaction give a negative as well as a positive flow, and why many neutral salts containing a strong acid (chlorides, for example) give a negative flow only. No substance of alkaline reaction has been observed to give a negative flow only, nor any strongly acid substance to give only a positive flow. An alkaline or electro-positive substance as the electrolyte, produces therefore by the 3rd method a positive flow, and an acid or electro-negative substance produces a negative flow. Numerous analogies may be detected in the behaviour of similar salts on ex- amining the Table. 37. The movements obtained by the 3rd method appear to be 250 results of a similar mutual attraction of the mercury and the ele- ments of the liquid to those obtained by methods 1 and 2. The mercury moves towards the cathode in acids because its positive end has acquired, by the aid of the electric current, a stronger affinity for the negative element of the liquid than its negative end has for the positive element, and moves towards the anode in alkalies because its negative end has acquired a stronger attraction for the positive element of the liquid than its positive end has for the negative ele- ment. I do not, however, give either this or the previous explana- tion (34) as an ascertained fact, but merely as a temporary hypo- thesis to aid further investigation. 38. The amount of positive flow produced by the 3rd method in strong aqueous hydrocyanic acid, or strongest solution of ammonia, is comparatively small, apparently on account of their inferior electric conductivity ; but if the smallest amount of ammonia is added to the hydrocyanic acid, the positive flow obtained is very strong ; also, if instead of ammonia a small quantity of caustic potash, soda, baryta, strontia, magnesia, lime, or even alumina is added to the acid, similar effects are produced : a little strontia or lime causes the nearest part of the mercury to dart up the watch-glass more than half an inch towards the positive electrode, if the battery is sufficiently strong. Silica had no effect. The addition of oxide of zinc, dioxide or protoxide of copper to the acid, reversed the direction of the flow, and dioxide of mercury neutralized the positive movement and diminished the conduction. The strongest positive flows obtained by the 3rd method were with strong solutions of alkaline cyanides, and the strongest negative flows with sulphuric acid. 39. The behaviour of liquids upon mercury in V-tubes by the three methods is not essentially different from their behaviour in a watch-glass ; the former, indeed, may be safely predicted from the latter. Sufficient pure mercury was placed in a V-tube of half an inch bore just to fill it at the bend, then a strong solution of sulphate of alumina poured upon it half an inch deep in each leg ; on con- necting the platinum wires from twenty-two pairs of small Smee's batteries with the solutions in the two legs, the liquid at once flowed from the negative to the positive leg ; but by lowering the negative wire into the mercury, it flowed from the positive to the negative leg : no flow of the liquid was produced by placing the positive wire in 251 the mercury and the negative one in the solution of the negative leg. If the mercury was too deep to allow the liquid to pass, the solution insinuated itself down the sides of the mercury in the positive leg (the positive wire being in the solution, and the negative one in the mercury) ; but by using a suitable depth of mercury, the whole of the liquid flowed from the positive into the negative leg. This is the usual behaviour of an acid liquid (or of one in which the nega- tive flow of method 3 predominated) with a suitable quantity of mercury in a V-tube. With a strongly alkaline liquid the only difference of behaviour is, that when the two wires are in the solu- tions of the two legs, the liquid flows from the positive to the nega- tive limb (see 16), i. e. opposite to the direction of flow with an acid. 40. There is a fixed relation between the direction of the electric current and the direction of each of the classes of movements ; for in every case where the former is reversed, the latter also becomes reversed ; but this effect is, of course, not observable in those cases of method 3 where two opposite and equal motions to the centre of the metallic globule exist. 41.1 have examined the influence of the chemical nature of the metallic globule upon the movements obtained by the 1 st method, in the following manner. The globule of mercury was first connected with the positive pole and the liquid with the negative pole for about ten seconds, and then the wires placed as in method 1 ; a temporary negative flow was produced for a few moments with certain liquids, apparently in consequence of the mercury absorbing a minute portion of an electro -negative constituent of the solution (?), and that sub- stance causing a negative flow in the succeeding operation until the whole of it was redissolved. The following liquids exhibited this phenomenon of reversion : — very dilute solutions of nitric acid, nitrates of ammonia, potash, soda, baryta, strontia (not of magnesia, appa- rently on account of viscosity of the mercury being produced), lime, zinc, lead, cobalt, nickel, copper, and dioxide of mercury ; also sulphates of ammonia and potash ; hypophosphite and diphosphate of soda ; and, strongest, the alkaline nitrates ; — but not dilute solu- tions of caustic potash, soda, baryta, or lime ; carbonates or bi- carbonates of potash or soda; carbonate of baryta; chlorides of ammonium, potassium, sodium, barium, strontium, magnesium, or VOL. x. T 252 calcium ; iodide or bromide of potassium ; sulphites of potash or soda; biborate, hyposulphite, or sulphate of soda; sulphate of lime ; arsenic acid ; cyanide of potassium ; oxalate of ammonia. The battery used was a series of 72 small Smee's elements. It appears from these experiments, that the direction of flow obtained by im- mersing the positive wire in the electrolyte and the negative one in the globule is strongly influenced by the chemical composition of the metallic globule. 42. The chemical nature of the globule exercises an equally powerful influence upon the direction of the movements obtained by the second method. If the mercury was first connected with the ne- gative wire and the solution with the positive wire for a few seconds, and then the connexions reversed or made as in method 2, a temporary and strong positive flow of the electrolyte for a few moments was obtained, apparently in consequence of the mercury absorbing a little alkali-metal or other electro -positive constituent of the liquid, and that substance causing a positive flow of the solution until the whole of it was redissolved. This positive flow did not occur while there was above a certain quantity of the alkali-metal in the mercury. The reversions were obtained in the following liquids : — dilute and strong solutions of caustic potash ; weak solutions of caustic soda, baryta, and lime ; carbonate of baryta ; chlorides of potassium, sodium, barium, strontium (not of magnesium, owing to viscosity of the globule), and calcium ; iodide and bromide of potassium ; sulphites of potash and soda ; biborate, hyposulphite, and sulphate of soda ; sulphate of lime ; arsenic acid ; cyanide of potassium ; and oxalate of ammonia ; also in solutions of hypophosphite and diphos- phate of soda ; — but not in very dilute nitric acid, nitrates of am- monia, potash, soda, baryta, strontia, magnesia, lime, uranium, zinc, cobalt, nickel, copper, or dioxide of mercury ; sulphates of ammonia, potash, or alumina. It is worthy of notice that these two series are almost precisely the reverse of those named with method 1 (41) ; t. e. those liquids which have the property of reversing the flow of one method have not that property with the other method, except hypophosphite and diphosphate of soda. The explanation suggested (34), of the cause of the true movements of methods 1 and 2 does not appear applicable to these phenomena of reversion. 43. Herschel has shown that with pure mercury in solutions of 253 alkalies or of sulphate of soda (vide Gmelin's * Handbook, i. 490, 492), if a little alkali-metal be introduced into the globule by connecting the latter for a few moments with the negative wire (the other wire being in the solution), a positive flow occurs on placing both the wires in the electrolyte with the mercury between them, and con- tinues until all the alkali-metal is redissolved ; and that similar effects are produced by adding small quantities of an easily oxidizable metal to the mercury — for example, potassium, sodium, barium, zinc, iron, tin, lead, or antimony, in the order given ; but not by bismuth, copper, silver, or gold. I have found that zinc added to mercury under a solution of sulphate of potash changed the direction of flow from positive and negative (obtained by method 3) to positive only ; cadmium did the same, but more feebly, and tin still more feebly ; bismuth had no apparent effect, but by using treble the electric power its effect was also similar, antimony also the same ; gold had no apparent effect even with a current from 72 pairs of Smee's elements. No positive flow was obtained by connecting the mercury with the negative wire and the solution with the positive wire for a short time in a liquid consisting of acid and water, and then placing both the wires in the electrolyte. Although there are many liquids (most of those which contain an alkali-metal) in which a temporary positive flow (or increase of positive flow) may be obtained by the 3rd me- thod by first placing the negative wire in the mercury for a short time and then returning it to the electrolyte, there are but few (among which are diphosphate of soda and arseniate of ammonia) in which a temporary negative flow is produced by placing the positive wire in the mercury and then returning it to the solution. It has been constantly observed with the 3rd method, that purity of the mercury is essential to the production of uniform results. From these various facts it appears that the chemical nature of the metallic globule strongly influences the direction of the movements obtained by method 3 ; also that an electro-positive globule produces a positive flow, and an electro-negative substance dissolved in the mercury produces a negative flow. 44. In some instances of the 3rd method — for example, with solu- tions of chloride of magnesium and nitrate of magnesia (35, Table), even the degree of dilution appears to determine the direction of the motion. No variation in the direction of the movement obtained by 254 either method was observed on varying the strength of the electric current, or on varying either the actual or relative distances of the electrodes from the metallic globule. 45. The presence of an electro-positive metal in one portion of the surface of the mercury will (by generating a small electric current) sometimes cause rotation of the electrolyte after the battery- wires are removed, especially if the mercury is touched with a pla- tinum wire beneath the surface of the liquid ; this is seen most frequently with mercury into which some alkali-metal has been deposited. 46. The general phenomena of .the movements may be briefly redescribed thus : — A. When both the wires are in the electrolyte, and the mercury between them, several cases occur : 1 . With a strongly alkaline liquid, a positive flow of the solution from the positive wire over the mercury to the negative wire occurs ; 2. With a strongly acid liquid, a negative flow of the solution takes place ; and 3. With a solution of a neutral or slightly alkaline salt, espe- cially of a salt composed of a strong acid and a strong base, two flows occur, a negative one from the negative wire towards the centre of the mercury, and a positive one from the positive wire towards the centre of the mercury, — the negative one being generally the strongest. If in this 3rd case the mercury contains any impurity, or if a substance be caused by any means to dissolve in the mercury, the movements are notably affected : an electro-positive substance (zinc, alkali-metal, &c.) increases the positive flow so as partly or completely to overpower the negative movement ; and an electro- negative substance increases the negative flow, in a few instances, so as to overpower the positive movement. These influences are also frequently detectable when liquids are used of alkaline or acid reac- tion, as in cases 1 and 2. B. When the negative wire is in the mercury and the positive one in the liquid, two cases occur : 1 . With pure mercury, the motion is positive in nearly all liquids, whether acid, alkaline, or neutral ; and 2. With mercury containing a small amount of an electro-negative substance, imparted to it by re versing the connexions of the wires for a short time, a temporary negative flow is produced in certain liquids, chiefly nitrates, but not in certain other liquids. C. When the positive wire is in the mercury and the negative 255 one in the liquid, also two cases occur : 1 . With pure mercury, the motion is negative in all liquids — acid, alkaline, or neutral; and, 2. With mercury containing a small quantity of an electro- positive substance imparted to it by reversing the connexions of the wires for a few moments, a temporary and strong positive flow is produced in certain liquids and not in certain others — and these liquids are almost precisely the reverse of those named under B, 2. The general influence of electro-positive substances dissolved in the globule is in all classes of cases to produce a positive flow, and of electro-negative substances to produce a negative motion; and the influence of electro-positive substances dissolved in the liquid is, in cases of A only, to produce a positive flow, and of electro- negative substances to produce a negative flow. 4/. The primary motions of the liquid and metal are, in all cases, wholly at their surfaces of mutual contact ; whilst the movements observed are only secondary effects, useful in enabling us to infer the direction of the original motions : the masses of liquid and metal serve merely as conductors of the electricity, and as stores of material for supplying the acting surfaces. The movements obtained are singularly symmetrical, probably in consequence of their essen- tially dual or polar character. 48. The essential nature or principle of the movements appears to be electro-chemical motion, i. e. definite motion directly produced by electro-chemical action. 49. To illustrate the action, I have constructed an apparatus consisting of two pairs of electrodes of platinum foil and mercury, suspended at opposite ends of two copper wires upon a central pivot, and rotating in an annular channel filled with dilute sulphuric acid ; but the power was too feeble to produce revolution of the necessary moveable parts : it was not more than sufficient to produce a manifest tendency to motion. In conclusion, I beg leave to suggest a trial of the sudden starts of the mercury by momentary currents as signals in electro-telegraphic apparatus. 256 January 19, 1860. Sir BENJAMIN C. BROD1E, Bart., President, in the Chair. The following communications were read : — I. "Abstract of a series of Papers and Notes concerning the Electric Discharge through Rarefied Gases and Vapours." By Professor PLUCKER, of Bonn, For. Memb. R.S. Re- ceived December 6, 1859. I. Action of the magnet on electric currents transmitted through tubes of any form. The action exerted by a magnet on the luminous electric discharge, passing through a tube or any vessel of glass which contains residual traces of any gas or vapour, may be generally explained, if we regard the discharge as a bundle of elementary currents, which, under the influence of the magnet, change their form, as well as their position within the tube, according to the well-known laws of electro-mag- netic action. The concentration of the discharge into one free arch only takes place if the arch be allowed to constitute a part of a line of magnetic force. [According to theory, there is no electro-magnetic action at all exerted on any element of a linear electric current which proceeds along such a line.] This condition, for instance, is fulfilled in the case of an exhausted sphere of glass, through which the discharge is sent by means of two small apertures, if the sphere be put on the iron pieces of an electro-magnet in such a way that the two aper- tures coincide with any two points of a line of magnetic force. There is another case of electro-magnetic equilibrium, which takes place if the current proceed along an " epibolic curve," i. e. along a curve, falling within the interior surface of the vessel, whose elements, regarded as elements of an electric current, are perpendi- cular to the direction of the electro-magnetic force and impelled by this force towards the surface. An exhausted cylindrical tube, when equatorially placed on the iron pieces of the electro-magnet, presents the simplest instance of this case. All elementary currents are con- centrated by the magnet along one straight line, which, according to the direction of the discharge and to the magnetic polarity, occupies 257 » either the highest or the lowest position within the tube. When the axis of the tube makes an angle of 45° both with the axial and equatorial direction, the epibolic curve is found to be a fine spiral. If neither of the two conditions mentioned above can be fulfilled, i. e. if the current cannot proceed either along a free magnetic or an epibolic curve, no voltaic arch will be obtained ; the current will be disturbed, and its light diffused. This, for instance, is the case when the above-mentioned cylindrical tube is placed axially on the two poles of the magnet : there will be seen above each of these poles a luminous epibolic straight line, lying within the horizontal plane which passes through the axis of the tube, one on each side of this axis ; but there exists neither a line of magnetic force nor an epi- bolic curve, joining the extremities of the two epibolic straight lines between the poles ; hence diffusion of light. There are other classes of phenomena not at all indicated and ex- plained by the laws of electro-magnetism. In many cases the magnet extinguishes the light of the current, without altering its intensity. I sent the discharge of Ruhmkorff s apparatus at once through two exhausted tubes, communicating by a copper wire. The first tube, about eight inches long and highly exhausted, was brought over the iron pieces of the electro-magnet into an equatorial position, while the second one was placed at some distance from the poles. Whilst the magnet was not excited, both tubes became luminous by the transmitted current ; when it was excited, the light of the first tube entirely disappeared, while the appearance of the second did not undergo the least change. Hence we conclude that the disappear- ance of the light does not prove the extinction of the current. Similar results are obtained when a tube having the shape of the annexed drawing is brought with its narrow middle part between the two iron pieces. In this case the light disappears where the magnetic action is greatest, but not in the other parts of the apparatus. Some- times before the light disappears, its colour is entirely changed, while in other cases, the magnetic force being less strong, only the change of colour takes place. The violet colour of sulphurous acid and of vapour of bromine is thus transformed into a fine green, and the blue of chloride of tin becomes a beautiful colour of pure gold. 258 If the magnet be strong enough, a phenomenon of the same kind is obtained when in the above-mentioned experiment the larger tube is put equatorially on the iron pieces, and the current concentrated in the lowest part of the tube. Then, where the magnetic action is greatest, the illuminated epibolic straight line is interrupted, termi- nating in two cusps, which in the case of sulphurous acid show a green colour. Waving light goes from one cusp to the other. In a room quite dark, highly diffused light is seen moving from one pole to the other, along lines of magnetic force. When the sphere previously mentioned is placed on the iron pieces so that the two opposite apertures fall within the equatorial plane, the transmitted current will be concentrated along an epibolic curve, which in this case is one of the two arcs of the great circle within the equatorial plane, supplementary to each other, and joining the two apertures. If it be the lower arc, turned towards the magnet, the epibolic current starting from the positive wire terminates in a cusp, where the action of the magnetic force, supposed generally to be strong, is greatest, while from the opposite side waving light enters the sphere. In this case there is only one cusp. II. The light of the negative wire bent by the magnet into curves and surfaces. In order to render the new class of phenomena most brilliant and well denned, larger tubes of a cylindrical shape, into which long wires enter at both ends, are to be selected. The light surrounding the negative wire must be as bright as possible, and the well-known dark space by which it is bounded must be very broad. The magnet acts on this light in a peculiar way, having no analogy with phenomena hitherto observed. I easily discovered the law giving in all cases the exact description of the phenomenon. The light emanating from any not isolated point of the negative wire, and diverging in all directions towards the interior surface of the surrounding tube, is bent by the action of the magnet into the mag- netic curve, ivhich passes through this point. According to the law already mentioned, such a curve is the only one along which an elec- tric current can move without being disturbed by the magnet. It equally represents the form which a chain of infinitely small iron needles, absolutely flexible and not subjected to gravity, would 259 assume, if attached with one of its points in the point of the negative wire. It is well known that a magnetic curve is completely deter- mined by a single one of its points. Therefore the whole light, starting from all the different points of the negative wire, will be con- centrated within a surface generated by a variable magnetic curve. The form of this " magnetic surface " varies according to the form of the negative wire, and its position with regard to the poles of the electro-magnet. When the negative wire lies within the equatorial plane, the magnetic surface assumes the shape of a vault ; when the wire lies within the axial plane, the whole surface is contained within the same plane, and generally bounded by very well defined magnetic curves. The negative light partly depends upon the substance of the wire. Particles of it, either pure or combined with the included gas, are carried off to the interior surface of the tube, which, when platina wires are used, consequently is blackened. If not acted upon by the magnet, all the part of the surface surrounding the platina wire becomes black ; if acted upon, only that line along which the surface of the tube is intersected by the magnetic surface is blackened. In this case, therefore, the particles separated from the wire move along magnetic curves. I think it most probable that the luminous electric currents in question are double currents, — going from the wire to the glass, and returning from the glass to the wire. The importance of the use of magnetic curves, or lines of magnetic force, in experimental researches, has been shown by several philoso- phers, especially by Mr. Faraday. Hitherto only filings of iron enabled us to give in peculiar cases an imperfect image of these curves. We may now trace through space such a curve in the most distinct way and illuminate it with bright electric light. III. The light of the positive wire and its spirals under the mag- netic action. The origin of the current takes place at the positive wire. If the negative wire is not too far from the positive, most striking pheno- mena are obtained when the magnet is acting on the formation of the electric current. In these experiments I made use principally of highly exhausted spheres, about two inches in diameter, through 260 which two platina wires, either parallel or perpendicular to each other, were conducted, whose shortest distance was about 0'8 of an inch. When, for instance, the sphere with parallel wires is put on the iron pieces of the electro-magnet so that both wires fall within the equatorial plane and are vertical, the whole circular section of the sphere passing through the negative wire is almost uniformly illu- minated by violet light, while the light of the positive electrode appears at one of its extremities, whence it moves, along an epibolic curve, to the corresponding extremity of the negative wire. On re- versing the polarity of the magnet, the illuminated epibolic curve passes from one extremity of the positive wire to the other, while the appearance of the negative light, after the reversion, is not at all altered. When the positive wire terminates within the sphere, we get, according to the magnetic polarity, either an epibolic curve, or dif- fused light, starting from the free extremity of the positive wire towards the surface of the circle illuminated by the negative light. When the sphere with crossed wires is put on the iron pieces so that the negative wire becomes vertical, the positive one horizontal and equatorial, — the whole surface of the axial circle passing through the vertical wire is illuminated, except the lower part, which is bounded by the magnetic curve starting from the lower extremity of this wire. There is no light seen on the positive wire, which is in- tersected by the magnetic circular surface. On this surface the shadow of the positive wire is most distinctly traced. [Shadows of this description are, in the general case, produced by beams of light starting from all points of the surface of the negative electrode, and moving along the corresponding magnetic curves. Not even the po- sitive wire deviates such beams of light from their curved paths.] Nothing at all is changed by a change of magnetic polarity. When the sphere is turned round its vertical diameter till the horizontal and positive wire passes from the equatorial direction into the axial, the whole surface of the axial circle passing through the negative wire is filled with illuminated magnetic curves. The positive light starts from the middle of the horizontal wire, and moves round it, within the equatorial plane, towards the negative wire without interfering with the light emanating from this wire. It constitutes 261 a fine spiral, separated by a dark space from the positive wire, taking its origin in a cusp, and expanding more and more when it approaches to the negative wire. In changing the polarity of the magnet, instead of the single spiral starting from the middle of the wire, we obtain two such spirals starting from the two extremities of the wire, impelled against the glass of the tube and revolving in the opposite sense. The phenomena just described and all the various phenomena of the same class may be fully explained by the laws of electro-magnetic action. For this purpose, we admit that the first element of each elementary current starting from any point of the positive wire is directed towards the negative wire. This supposition follows from the observed fact, that the positive wire, if parallel to the negative, becomes luminous along its whole length on that side which is turned towards the negative wire. When acted upon by the magnet, these first elements, bound to the positive wire, are allowed to move freely along this wire. The single point, or the system of points, where all the first elements meet before leaving the wire, may easily be deter- mined. The following elements, subjected to the same force, are entirely at liberty to obey it. This action may generally be defined thus : — Imagine an element of the elementary electric current starting from any point of a magnetic curve, which connects both poles ; imagine also the molecular currents (as assumed by Ampere) within the magnet continued round this magnetic curve. Then, if the element be perpendicular to the magnetic curve, the full action of the magnet turns it round the curve in a direction opposite to the direction of Ampere's molecular currents. If it be not perpendicular, this action is to be decomposed along the normal to the magnetic curve within the osculating plane. I think it worthy of notice, that the same electro-magnetic laws, applied to magnetic action on an already formed electric current, either bound to the conducting wire or free to move in space, equally hold in determining the path of the current when acted upon by the magnet during its formation between the two electrodes. Thus a moving electric particle, under magnetic action and tending towards the negative electrode, may be regarded as describing a curve, in an analogous way as a projected material point does — acted upon by gravity. IV. Electric currents returning on their own path. When only one of the wires of Ruhmkorff's apparatus is in contact with one of the electrodes of a long and large exhausted tube, while the second wire is isolated, or, what is preferable, communicates with the earth, an electric current is obtained entering the tube and re- turning on its own path. The existence of the two currents is most evidently proved by the magnet, which, acting differently on both, divides the double current into two of the same intensity. This intensity is much increased by touching the tube with the hand at any distance from the electrode which communicates with Ruhm- korff's apparatus. A double current of exactly the same description is obtained in a narrow tube, which may be one foot long, communicating with a larger tube, both electrodes of which are connected with the wires of Ruhmkorff's apparatus. When the extremity of the narrow tube is touched with the hand, a current starting from the principal tube enters the narrow one, proceeds to its extremity, and finally returns to the principal tube : which is proved by the magnet. When, through a tube whose shape is represented by the drawing, the discharge was sent from A to B, the current, passing from the narrow tube into the surrounding larger one, was, when it arrived at the extremity of the narrow tube, partly branched off in an oppo- site direction towards A, and then, changing its course again, moved towards B. There is another case where returning currents are obtained. When the discharge on its way through a highly exhausted tube passes from a large space into a narrow channel, a part of the current is reflected, and returns on its own path within the larger space : which is again proved by the magnet. Mr. Gassiot first observed and described what he calls "recipro- cating currents," and the separation of such currents by the magnet. That celebrated philosopher had the kindness himself to show me his experiment, and even enabled me to repeat it, by obliging me with one of his fine Torricellian-vacuum tubes. I do not exactly know his 263 opinion on the nature of those currents ; for my part, I think they are induced currents returning on their own path. This opinion was supported by the subsequent experiments. I got a hollow and highly exhausted sphere of glass about 2 inches in diameter, into which no wire entered, and placed it on the iron pieces of the electro-magnet. On touching the sphere with one of the wires of RuhmkorfFs apparatus, diffused light was spread through it. By the excited electro-magnet this diffused light was con- centrated into a luminous stream, which moved along the magnetic curve determined by the point touched, from this point to another one in which the interior surface of the sphere is intersected a second time by that curve, and evidently returned in the same curve from the second point to the first. When the point where the sphere is touched by the wire falls within the equatorial plane, no part of the magnetic curve in question, which in this case is a tangent to the sphere, enters it. In this peculiar case, the phenomenon is entirely changed, the light of the induced current constitutes an ascending or descending stream proceeding along the epibolic curve within the equatorial plane. In reversing either the polarity of the magnet or the direction of the discharge, the ascending stream is transformed into a descending one, or vice versd. But there is no change of the appearance in the general case. When the sphere is simultaneously touched by the two wires of Ruhmkorff s apparatus in two different points, we get within it two independent luminous currents showing no reciprocal action on each other ; and it is only when both points belong either to the same magnetic curve or to the epibolic one, that there is but one luminous arch along that magnetic or the epibolic curve. All this shows that Gassiot's induced streams are subject to the same laws as the direct currents are, formerly observed by myself. In all experiments mentioned in this section, the discharge of Ruhmkorff 's apparatus may be replaced by a spark taken from the conductor of an electrical machine. V. Fluorescence produced by the electric discharge. Glass shows in sunlight scarcely any kind of fluorescence. A glass tube, including residual traces of a proper gas, becomes highly fluorescent when the electric discharge is sent through it : a fine green 264 colour appears in the case of common German glass, a fine blue if the glass contain lead. Hitherto I have tried in vain to get speci- mens of a different and well- determined chemical composition, which, without doubt, would offer new and curious cases of fluorescence*. A beautiful fluorescence is obtained by surrounding suitable ex- hausted tubes, through which the discharge is passing, with a solution of eesculine, of fraxine, of sulphate of quinine, &c. If the tubes include residual traces of hydrogen, scarcely any fluorescing light is seen ; if they contain traces of nitrogen, on the other hand, the fluores- cence is very intense. All depends upon the nature and the density of the gas. In certain cases, a very faint electric light, scarcely seen by the eye, produces a brilliant fluorescence, especially when the light, if belonging to the negative wire, is concentrated by the magnet. M. Geissler, in constructing his tubes, first observed (about eighteen months ago) the fluorescence of gases, which even continue luminous some seconds after the interruption of the current : further researches will explain this curious phenomenon. VI. The spectra of the electric current in rarefied gases and vapours. The light of the electric discharge through large tubes is rather too much diffused to give a distinct spectrum. I made trial, therefore, of sending the discharge through a capillary tube, and fully succeeded. I got a brilliant luminous line within the tube, of which a beautiful spectrum was obtained by replacing the distant illuminated slit, which Fraunhofer used in his observations, by the self-luminous line. Afterwards I employed Babinet's goniometer. The slit of this instrument was illuminated by the current within the capillary tube, which was placed before it at a distance of about 0*4 of an inch. The aperture of the slit could be changed ; but where it is not particularly mentioned, it was seen under a constant angle of 3'. After having interposed the prism of heavy flint glass, the refracted image of the slit, in the general case, was found to be divided into a less or greater number of differently coloured bands, appearing each under the just-mentioned constant angle of three minutes. Hence it follows that the analysed electric light is com- * From the beautiful experiments recently made by E. Becquerel, we may deduce a satisfactory explanation of these phenomena. 265 posed of a certain number of rays, whose refrangibility is a discon- tinuous one. The refraction of each ray is determined by the angle between the middle lines of the image of the slit, seen directly, and of the corresponding refracted band. This angle is independent of the aperture of the slit, and remains the same if the slit be reduced to a physical straight line. There cannot exist a deflected band smaller than 3' ; i. e. no such band appears under an angle less than the angle under which the aperture is seen directly, without the interference of the prism. This law holds through all my numerous observations of electric spectra. [I find difficulty in applying it to the case of the common solar spectrum.] There are, in many instances, bands observed which are seen under an angle greater than 3' ; but generally such bands are resolved into two or more bands of single breadth. In some instances where the angle in question does not reach the double of 3', there appears in the middle part of the band a bright line ; larger bands are generally divided by small, well-defined, dark lines. In order to distinguish the rays of different refrangibility in the different gases, I denoted such a ray by adding to the symbol belong- ing to the gas the Greek letters a, (3, y, indicating the succession of the corresponding bands in each spectrum. Accordingly, for instance, the band Ny, appearing under an angle of 6', is divided by a dark line into two ; the bands NS and N0, having each a breadth of 10', are divided by two dark lines into three single bands. The bands Hga and Sn Cl2y, 5' broad, show a bright middle line. The space between two bright bands is either absolutely black, or of a greyish tint, or of a faint tint of that colour which is indicated by the position of the space within the spectrum. With regard to these faint tints, the eye, by the effect of contrast, is commonly a very bad judge of colour, and there may easily be a deception, admitting a succession of colours in the spectrum which in reality does not exist. I cannot enter here into the details by which I obtained exact measures of the minimum refraction of the different rays. All measures were taken without deranging the adjustment of the gonio- meter ; for ascertaining its constancy, each spectrum was compared with the spectrum of hydrogen. From the angles of refraction, I deduced the indices of refraction, and hence the corresponding lengths 266 of waves expressed in millionths of a millimetre in order to get abso- lute numbers immediately comparable with those of others. The discharge through a capillary tube containing residual traces of pure hydrogen is of a deep red colour ; the spectrum obtained from it consists of only three bright bands : — of a most splendid red one, Ha; of a bluish-green one, H/3, nearly as bright ; and of a fainter violet one, Hy. The following table contains the angle of refraction 0, the index of refraction yu, and the length of the wave X, corresponding to each of the three rays Ha, H/3, Hy, as well as of the dark lines of Fraunhofer, C, F, G, in order to compare their reciprocal position : — Ha.... 57° H)'-5 C.... 57° 8'-5 H/3 59 55-5 F.... 59 55-5 Hy.... 61 43 G.. . 61 55-5 Ha.... 1-7080 C 17077 H/3. ... Hv.. 1-73255 17481 F G. . 1-73255 17498 Ha.... 653-3 C 656-4 H/3.... 484-3 F...... 484-3 Hy 433-9 G 429-1 From this table it results that H/3 exactly coincides with F, while Ha and Hy approach very near C and G. The spectrum of pure oxygen was only obtained after several un- successful trials to procure proper tubes, the gas being in most cases absorbed by the electrode during the passage of the current. The spectrum of nitrogen is one of the richest in colours. Its less refrangible part is of a peculiar nature, having, from the exterior red to the limit of the yellow, seventeen equidistant small dark bands. Most characteristic are the spectra of carbonic acid (oxide of carbon), iodine, bromium, chlorine, chloride of silicium, chloride of phosphorus, chloride of tin. The spectrum of the last-mentioned substance is one of the most remarkable. The colour of the gas within the larger parts of the tube through which RuhmkorfFs 267 apparatus is discharged, is a dark blue, in the capillary part of the same tube the finest gold-colour, while the light surrounding the negative wire is of a fawn-colour. [The finest appearance is obtained with a larger tube containing residual traces of the vapour of this salt, put on the iron-pieces of a powerful electro-magnet ; within the blue light of the discharge numerous golden flashes are produced, and variously directed by the magnetic force.] A piece of metallic sodium within an atmosphere of rarefied hy- drogen does not alter the spectrum of this gas when at the ordinary temperature ; but when it is heated, a single brilliant yellow band is added to the three original bands of hydrogen. The middle of the new band exactly coincides with Fraunhofer's dark line D. The vapours of the metal are condensed in the cooler parts of the apparatus. Phosphorus, when treated in the same way, instead of adding new bands to those of hydrogen, at a certain temperature even extin- guished the spectrum of the gas. In the case of mercury, I gave to the tube the shape of the annexed drawing. The electrodes merely entered the two flask-shaped ends of the tube, where they were covered about half an inch with mercury. Peculiar bands were obtained without heating the mercury ; when it was heated, the spectrum became most brilliant. When traces of two gases, not acting on each other, are mixed within a spectrum -tube, the spectra of both are simultaneously obtained. A result of some importance, following from the researches of which I have here given an abstract, is, that in all such dioptrical researches, where Fraun- hofer's dark lines were used in order to get exact measures, these dark lines may with great advantage be replaced by the middle lines of the new brilliant bands of the gas spectra. To these bands the most convenient breadth may be given in each particular case by regulating the aperture of the apparatus. A spectrum-tube of hydrogen, exhibiting three well-defined bright bands, is well suited for this purpose. During a whole year I made use of such a tube, which remained absolutely unaltered. Every gas being characterized by its spectrum (even by one of the VOL. X. 268 bands of the spectrum, the position of which is measured), we get a new kind of chemical analysis. In this way only we may ascertain the residual contents of the exhausted tubes, and the changes they undergo, either suddenly by the discharge, or gradually afterwards. Thus, for instance, a spectrum-tube in which traces of vapour of sulphuretted carbon were enclosed, presented most unexpectedly the combined spectra of hydrogen and oxide of carbon. Hence we con- clude that there remained also within the tube some traces of vapour of water, which was decomposed as well as the sulphuretted carbon. Traces of sulphur were deposited on the interior surface of the tube, while oxide of carbon and hydrogen remained within it. Nearly all examined combinations of hydrogen with metals, with chlorine, &c., were almost instantly decomposed. The spectrum of hydrochloric acid was found to be the combined one of hydrogen and chlorine. Sulphur and arsenic were deposited from their combi- nations with hydrogen, the former constituting fine dendrites, the latter well-defined large bands : the spectrum in both cases was that of pure hydrogen. Seleniated hydrogen showed within the capillary tube a fine yellow tint, but this tint was converted during the passage of the discharge into a brilliant red one ; the change of colour started from one of the extremities of the capillary tube, and reached the other one after a few seconds. The spectrum observed during this change of colour was in the first moment a most distinct one, showing, for instance, between H/3 and Hy two similar systems of two brilliant blue bands separated by a black one about double as large ; but this spectrum entirely disappeared, as in dissolving views, being by and by replaced by the spectrum of hydrogen. A few minutes after the discharge was stopped the red colour turned again into the primitive yellow one, the gas decomposed by the discharge having been re- composed again. Thus the same experiment could be repeated any number of times. [Similar chemical effects were ascertained in a different way in the case of sulphurous acid, which, if included within a larger tube, shows a fine stratification of narrow .violet bands. When the discharge passes during several minutes, the stratification is altogether changed, the narrow violet bands being transformed into the large clouds of the best Torricellian vacuum tubes. The primitive condi- tion of the gas is restored by heating the electrodes ; but in every 269 new experiment the phenomena became less distinct than they were before.] I think it most probable that, properly speaking, electric light does not exist ; the light which we see belongs to the gas, rendered incandescent by the thermal action of the current. Accordingly, in our case, the colour of the appearing light depends upon the nature of the gas and the concentration of the current. This opinion is strongly supported by the observed fact, that the temperature of the capillary tube increases considerably in some instances. Considering that this increase of temperature has its source in the heat of the residual gas, which is too small in amount to be indicated by the balance, this heat being produced by the electric current, and com- municated to the heavy substance of the tube ; we have scarcely an idea of the enormous temperature of the gaseous electrode included in the capillary channel*. II. " On the Interruption of the Voltaic Discharge in Vacuo by Magnetic Force." By J. P. GASSIOT, Esq., F.R.S. Re- ceived December 6, 1859. The late Professor Daniell, in his Fifth Letter on Voltaic Combina- tions (Phil. Trans. 1839, part 1), describes some experiments made with seventy series of his constant battery, and states (page 93) " that the arc of flame between the electrodes was found to be attracted and repelled by the poles of a magnet, according as one or the other pole was held over or below it, as was first ascertained by Sir H. Davy ; and the repulsion was at times so great as to extinguish the flame." In the Philosophical Magazine of July 1858, Mr. Grove has de- scribed an experiment made by him with one of my vacuum-tubes, 2 feet 9 inches long, in which he ascertained that the discharge of a Ruhmkorff s induction coil could be stopped by bringing a magnet near the positive terminal wire, but that this effect was not obtained when the magnet was made to approach the negative. The mercurial vacuum-tube in which Mr. Grove observed this phenomenon was * In some peculiar cases my primitive theoretical views were modified, reformed, or extended by subsequent experiments. The abstract now given refers only to what I think at present to be the state of the question. u 2 270 unfortunately shortly afterwards broken ; and although Mr. Grove and myself have repeatedly endeavoured to obtain the same result in similar and in other vacuum-tubes (and since that period I have ex- perimented with upwards of two hundred), all our efforts have been hitherto unsuccessful. The experiments I am now about to describe were made with two carbonic acid vacuum-tubes, the vacua being obtained in the same manner as described by me in the Philosophical Transactions, part 1, 1859. A, in the annexed figure, represents a glass tubular vessel (No. 146), 24 inches long and 6 inches diameter in its wide part ; at one end, attached to the platinum wire (#), is a concave copper plate 4 inches diameter, at the other end is a brass wire attached to the platinum wire (b). B represents a glass tube (196) 5 inches long (in its wide part), in which two small balls of gas-retort coke are attached to the platinum wires a' and V, and are placed about 3 inches apart, all the platinum wires being hermetically sealed in the glass. In A the potash is placed in the vessel between the electrodes ; in B it is placed in the further part of the tube, beyond one of the wires. An electro-magnet is placed at C, and is constructed so as to allow the two helices to be separated ; and by these means the larger vessel can, if required, be placed between them, and any portion of the luminous discharge may be thus exposed to any part of the magnetic field. Battery. * The carbon -balls do not in these experiments affect the results described, as I have obtained the same in a tube of the same dimension with brass wires. 271 When the terminals of an excited induction coil are attached to the wires of either of the above vacuum-tubes A or B, luminous discharges are obtained, the negative wire ball or plate being covered with a luminous cloud-like glow extending towards the positive ; but the stratifications are not developed, except by the magnet, and these become more clearly defined as the magnet is caused to approach, or as the power is increased, when they are de- flected according to the direction of the discharge, or of the polarity of the magnet. But with the induction coil, no matter how I re- duced the intensity of the discharge, or varied that of the electro- magnet, in no instance could I produce in these, or in any of my vacuum-tubes, a similar result to that which Mr. Grove obtained in the vacuum-tube so unfortunately broken ; the experiment evidently requires a certain balance of power between the electric discharge and that of the magnet, and this I had hitherto been unsuccessful in obtaining. I next experimented with my water-battery (Phil. Trans. 1844, and Proceedings, 26 May, 1859), which I have recently had carefully cleaned and recharged with rain-water ; the luminous discharge in both the vacua A and B was obtained with less than 1 000 series, and this discharge, as well as that from the full series of the battery of 3520 cells, was under certain conditions, hereafter described, entirely destroyed or interrupted by the power of the magnet. At first the interruption or break in the luminous discharge ap- peared to be caused by the sudden action of the magnet, as if it were merely momentarily blown out, for the discharge recovered itself while it remained under the influence of the magnet — the luminous discharge under this condition gradually reappearing stratified and strongly deflected ; but I subsequently ascertained that, by carefully adjusting the intensity of the battery discharge, and the force or power of the electro-magnet, this recovery in the discharge could be en- tirely prevented. On approaching the vacuum A towards the electro-magnet, the luminous discharge from the battery assumed the same form as that from the induction coil ; but when the vacuum was placed between the helices, so as to permit the armatures or poles of the magnet to touch one or each side of the glass vessel at about its centre, the discharge disappeared ; as soon as the magnet was removed, or the 272 vacuum-tube withdrawn from its influence, the luminous discharge was reproduced. To test whether a complete disruption of the electrical current had taken place, two gold-leaf electroscopes were attached, one to the zinc and the other to the copper terminal of the water-battery ; the leaves diverged with considerable energy ; connection was then made from the electroscopes to the wires of the vacuum-tube ; the luminous discharge became visible, and the leaves of both electroscopes par- tially collapsed ; the vacuum-tube was then placed as before, between the armatures of the electro-magnet, and immediately the magnet was excited, the luminous discharge disappeared, and the leaves of the electroscopes diverged to their original maximum extent, thus proving the disruption to be complete. If the smaller tube B is placed across both poles of the magnet, the luminous discharge at its centre assumes the appearance of being nearly separated into two parts, each part showing a tendency to rotate round the pole of the magnet on which it is placed, the one in an opposite direction to the other. I endeavoured to obtain a disruption of the battery discharge when in this state, and possibly with a more powerful electro-magnet this experiment would succeed ; but although I reduced the intensity of the battery discharge and increased the power of my electro-magnet, I could not in this manner obtain an actual discontinuity of the battery discharge ; but when the same vacuum-tube was placed in a longitudinal or equatorial position between the poles, or even approached them within three or four inches in that direction, an immediate interruption of the dis- charge took place. When both vacuum-tubes are placed in the battery circuit, the interruption can be shown in a very striking manner : the general arrangement of the apparatus represented in the figure shows how this experiment is. made. A is fixed on a wooden support. One wire (5) is attached to the copper terminal of the battery, the other wire («) being connected to one of the wires in B, which is held by the hand, the other wire (£') being connected with the zinc terminal of the battery, gold-leaf electroscopes being placed as before. In this manner all the apparatus is fixed except B, which being held by the hand, and the connecting wires being flexible, can be placed in any required position. 273 As long as the vacuums are at a sufficient distance from the action of the magnet, the luminous discharge is visible in both, and the leaves of the electroscopes partially collapse ; but immediately the discharge in B is placed in the position described in the previous experiment, between the poles of the magnet, the discharges in both vacua instantly disappear, and the leaves of the electroscopes di- verge to their original maximum. The actual position of what is termed the magnetical field, around and between the poles of a magnet, has been generally delineated by means of iron filings placed between the poles on a sheet of paper. Assuming the lines in which these particles arrange themselves to represent the direction of the power of the magnet, or the magnetic field, they also explain the actual position through which the vacuum- tube should be placed to obtain the preceding result, and in this manner to show by experiment that a voltaic discharge which has sufficient intensity to pass through a space of upwards of 6 inches in attenuated carbonic acid gas is not only interrupted, but absolutely and entirely arrested by magnetic force. Postscript (received Jan. 19, 1860). — In repeating the experiments with Dr. Tyndall in my laboratory, the disruption of the luminous discharge in vacuo from 400 cells of the nitric-acid battery was obtained : some most beautiful and striking results were obtained from the same battery on the 16th inst., on repeating the experiment in the Theatre of the Royal Institution, with its large electro- magnet, Dr. Faraday and Dr. Tyndall being present. The large receiver (146) was placed between the poles of the electro -magnet, the lines of force going through it; electrodes equatorial. The stratified discharge was extinguished. Subsequently, through the sinking of the battery, or some other cause, the stra- tifications disappeared, and the luminous glow which filled the entire tube remained. On now exciting the magnet with a battery of ten cells, effulgent strata were drawn out from the positive pole, and passing along the upper or under surface of the receiver, according 274 to the direction of the current. On making the circuit of the magnet, and breaking it immediately, the luminous strata rushed from the positive arid then retreated, cloud following cloud with a deliberate motion, and appearing as if swallowed by the positive electrode. The amount of electricity which passed appeared materially in- creased on exciting the magnet ; once the discharge was so intense as to fuse half an inch of the positive terminal. After this had occurred, the discharge no longer passed as before when the terminals of the battery were connected with it ; but on connecting the positive end of the battery with the gas-pipes of the building, the discharge passed. The discharge could also be extinguished by the magnet ; and the time necessary to accomplish this, furnished a beautiful indication of the gradual rise and reduction in the power of the electro- magnet. III. " On Vacua as indicated by the Mercurial Siphon-Gauge and the Electrical Discharge." By J. P. GASSIOT, Esq., F.R.S. Received January 19, 1860. That the varied condition of the stratified electrical discharge is due to the relative but always imperfect condition of the vacuum through which it is passed, is exemplified by the changes which take place in the form of the striae while the potash is heated in a carbonic acid vacuum-tube. In order, if possible, to measure the pressure of the vapour, I had a carefully prepared siphon mercurial gauge sealed into a tube fifteen inches long, at an equal distance between the two wires A, B. This tube was charged with carbonic acid in the manner described 275 by me in a former communication. When exhausted by the air-pump and sealed, it showed a pressure indicated by about 0*5 inch difference in the level of the mercury ; the potash was then heated ; the mercury gradually fell, until it became perfectly level. Dr. Andrews (Phil. Mag. February 1852) has shown, that with a concentrated solution of caustic potassa, he obtained with carbonic acid a vacuum with the air-pump so perfect as to exercise no ap- preciable tension, as no difference in the level of the mercury in the siphon-gauge could be detected. On. trying the discharge in the vacuum-tube after the potash had cooled, I found it gave the cloud-like stratifications, with a slight reddish tinge ; consequently not only was the vacuum not perfect, as denoted by the form of stratification, but in this tube the colour denotes that even a trace of air remains, — probably that portion in the narrow part of the siphon-gauge, which, from its position, was not displaced by the carbonic acid. The potash was subsequently heated until the discharge was reduced to a wave-line, with very narrow strise ; in this state moisture is seen adhering to the sides of the tube ; but even in this state the difference in the level of the mercury in the gauge did not ever vary more than "05 inch. As the potash cooled, the discharge altered through all the well-known phases of the striae, the mercury again becoming quite level. At first almost the slightest heat applied to the potash alters the form of the stratifications ; as the heating is repeated, longer appli- cation is necessary ; but it shows how sensibly the electrical discharge denotes the perfection of a vacuum, which cannot be detected by the ordinary method of mercurial siphon-gauge. January 26, I860. Sir BENJAMIN C. BRODIE, Bart., President, in the Chair. The following communications were read : — 276 I. "On the alteration of the Pitch of Sound by conduction through different Media." By SYDNEY RINGER, Esq., late Physicians' Assistant at University College Hospital. Communicated by Dr. GARROD. Received November 25, 1859. Having observed that the pitch of cardiac murmurs underwent various alterations dependent on the constitution of the conducting body, the following experiments were devised to extend and render more certain the observations made on the human subject. In most of these experiments a tuning-fork was used, and in all the alterations in pitch were tested by the ear. In making these experiments, the note of the vibrating fork was first taken with the instrument close to the ear and without being in contact with any resounding body. It was next placed on the body which was experimented on, and lastly listened to through the medium of the same. The alteration in pitch obtained by these two latter methods gave always the same results in kind, but Dot in degree, the alteration being always greater when the note was heard through the medium of the conducting body. SOLIDS. A board 1 3 feet long was balanced on the back of two chairs. The note of the fork was then taken, without its being in contact with the board. The fork in vibration being next placed at one end of the board, the ear was placed on the other, and the note was then found to be most appreciably lowered in pitch. As boards composed of various kinds of wood were not obtainable, tables were used. Of all the woods thus tested, deal lowered the pitch most ; indeed the lowering of the pitch was always in proportion to the porosity of the wood f . The pitch was found to fall the greater the distance from the fork. *Bone lowered it. Glass raised the pitch. Iron raised it. t Dr. Wylde, the Conductor of the Philharmonic Society, kindly examined and fully corroborated, in those experiments marked with an asterisk, the conclusions I had previously come to. All the experiments were confirmed by numerous persons of acute ear. In no case was their opinion at variance with my own. 277 The two last, in conducting the note, greatly lessened the intensity, much more so than the substances described above. The muscular substance of the heart lowered the pitch. Skin and cellular tissue, on the contrary, raised it. LIQUIDS. A large foot-pan was filled with water, and the vibrating fork was partly introduced into this, but as no sound could be heard in this manner without some resounding body, a small circular piece of wood was used for this purpose ; the fork placed on this was first listened to ; the fork with the piece of wood was then placed under the water ; one ear was then immersed in the water, and the note so taken ; the pitch was then found to be most decidedly heightened. Any objections to this method of performing the experiment were obviated by the following extension of it. The eyes being firmly shut, any variation in the position of the fork, that is to say, whether it was moved closer to or further from the ear, was accurately determined by the alteration in the pitch. Next, a glass tube 29 inches long, with a diameter of -f ths of an inch, was closed at one end, with a diaphragm of gutta percha, oil- silk, or bladder (the same diaphragm being used in each set of com- parative experiments). The tube was then filled with the fluid to be examined. The ear being applied to the diaphragm, the stem of the vibrating fork was introduced above into the fluid, care being taken that neither the finger nor the fork was in contact with the glass. Ex- periments conducted in the above manner gave the following results. * Water raised the pitch most appreciably. * Alcohol still higher. Ether higher. A solution of protocarbonate of soda of the same specific gravity as the blood, raised the pitch more than pure water. * A saturated solution raised it still higher. * Sulphate of baryta, suspended in water, raised it higher than any other tried fluid. Prussian blue, suspended in water, raised it more than water, but less than the sulphate of baryta. From the above results it appears that simple fluids heighten the pitch in proportion to their diminished specific gravity, and that the 278 addition of any substance (though increasing the specific gravity), whether in solution, or merely suspended in the water, heightens it ; that particles in suspension, indeed, heighten it more than solutions. The fact of different fluids raising the pitch in variable degrees, excludes the possibility of the rise being due to the glass, or any other material used, unless the fluid varying in weight altered the pitch, by affecting the tension of the diaphragm ; but the fact of the alteration in pitch bearing no relation to the specific gravity of the fluid excludes this source of error. The following experiments were devised to test the influence of running water on the pitch. Into an india-rubber tube, 1 3 inches long, and f ths of an inch diameter, a funnel was inserted ; immediately below this a small opening was made, just large enough to admit the end of the fork. Water was kept constantly running through this, and the stethoscope (covered with a diaphragm) applied to different parts of the tube ; by this method the pitch was found to be most appreciably raised the further from the fork the stethoscope was applied to the tube. The elevation of pitch was easily recognized at a distance of 2^ inches (the length of the pulmonary artery and adjoining part of the aorta). The stethoscope having been unfortunately left behind, Dr. Wylde could only apply the ear directly to the tube, and therefore could not speak so decidedly as he did concerning the other experiments, but he was of opinion that the pitch was raised as stated above. It was next attempted to be ascertained whether the mere motion of the water increased or diminished the rise of the pitch. It ap- peared that the pitch was very slightly raised by the mere motion of the fluid, the same point of the tube being listened to. The difference in intensity was most marked. The chief object of these experiments being to ascertain the in- fluence of the different constituents of the human body on the pitch of cardiac and other murmurs, and in order that the experiments might, as closely as possible, simulate the actual phenomena in the body, an aorta was tied to the mouth of a tap, and an artificial murmur produced by causing a constriction of the vessel by a piece of twine tied round it. The pitch of the murmur so produced was decidedly raised the further it was heard along the vessel from the point where the sound was generated. 279 To set the question quite at rest of the possibility of the blood in a vessel raising the pitch, especially at so short a distance as 2| inches, the following experiment was devised : — A tourniquet was placed over a man's femoral artery, immediately below Poupart's ligament, and an artificial murmur thus produced ; this was found to rise rapidly in pitch in passing down the course of the vessel. A well-marked difference was noticed at a distance of only an inch, and decidedly more at a distance of 2^ inches. The intensity of the murmur quickly diminished in passing to the right or left of the vessel, the pitch being at the same time rapidly raised, which was due to the interposition of integuments ; but this interposition could not be the cause of the rise of the pitch in the course of the vessel, as the murmur could be heard in that direction at a distance of at least 6 inches, whilst it was completely lost at less distance than 2 inches to either side of the vessel ; thus the murmur must have been conducted by the blood, whilst the same thickness of integuments was over the artery at the lower and the upper point listened to, for both points were above the place where the sartorius muscle crosses the vessel. GASES. If a watch is pressed close to the ear and then gradually moved away, the tick is heard to rise in pitch in proportion to the distance the watch is withdrawn. *Or, if in place of the watch a tuning-fork be used, the same can be still more distinctly ascertained. Then let the fork, either freely . vibrating, or, still better, placed on a resounding board, be moved gradually away from the ear, the pitch will be found to rise the further the fork is carried away from the ear. An echo of a musical note is higher pitched than the original note. Again, a loud cardiac murmur audible over the entire chest was examined in the following manner: — The patient was directed first to exspire to the utmost, and the pitch of the heart-sound was then ascertained ; he was then ordered to inspire to the full ; the pitch was then found to be raised. In this experiment, the only variation was an increased amount of air between the point where the murmur was generated, and the ear of the observer. 280 The substances which lowered the pitch in the above experi- ments have one common property, namely, porosity, and, as far it could be ascertained, the depression of pitch was in proportion to this condition. Is it possible that the small vacuities included in the substance, acting as resounding cavities, and reflecting the vibrations from their walls, may so direct them that they may somewhat interfere with one another, and thereby be somewhat diminished in number ? The following experiment tends in some degree to support this con- jecture. It is well known that if the vibrating fork be held obliquely, resting on the table, " a loud resonance is audible ; but if the tuning- fork be moved parallel to itself along the surface of the table, the resonance of the table immediately ceases from the interference of the planes of vibration with each other ;" but if the fork is moved so slowly, and so that the resonance is not completely destroyed, the pitch falls slightly. Again, if the fork be applied to the head, and listened to first with the ear open, and afterwards with the ear closed, the pitch is found to be slightly lowered. In all those experiments in which the pitch was elevated by con- duction, it was found that there was diminished intensity in pro- portion to the elevation of pitch ; thus it would appear that all bodies raise the pitch in proportion to the difficulty with which they receive and conduct vibrations. Dr. Scott Alison has proved in some recent experiments, that the conductivity of media, as regards rapidity, does not correspond with that of intensity. Of all tried substances, iron was the worst con- ductor as regards intensity, and this was found to raise the pitch most. The above explanation is rendered somewhat probable from the fact that in all cases the elevation was greater with a weak note than a strong one. Dr. Wylde tells me that it has long been noticed by musicians that a weak note is somewhat higher pitched than a strong one, it being under these circumstances caught through the medium of the air. Those bodies which, on the contrary, lower the pitch, do so to a greater extent with a weak note. These explanations are offered with the utmost diffidence, on ac- count of my very limited knowledge of acoustics. On looking into the literature of the subject, the only reference to 281 alteration of pitch by conduction is that by Dr. Walshe*, who ascribes it to transmission of the vibrations through "varying" media. II. " On the frequent occurrence of Phosphate of Lime, in the crystalline form, in Human Urine, and on its pathological importance." By ARTHUR HILL HASSALL, M.D. Lond. Communicated by Dr. SHARPEY, Sec. R.S. Received November 9, 1859. In 1854 I submitted to the Royal Society a paper "On the frequent occurrence of Indigo in Human Urine." This communi- cation, which was published in the ' Philosophical Transactions,' attracted considerable attention both at home and abroad. The singular fact of the frequent presence of indigo in the urine, first announced by me, has since been amply confirmed by a variety of observers. I have now to place before the Society some investiga- tions in relation to the not uncommon occurrence in human urine of phosphate of lime, as a deposit, in a well-marked crystalline form. When the earthy phosphates are treated of by writers, in con- nexion with the urine, they are usually described collectively, and it is seldom that each kind of phosphate is particularized, and yet there are several which may occur either separately or together. The phosphate of ammonia and magnesia, or triple phosphate, is indeed often specified, but rarely is phosphate of lime separately mentioned, and phosphate of magnesia scarcely ever ; and yet phosphate of lime is very frequently present as a deposit in urine, much more so, indeed, according to my experience, than the triple phosphate, excluding those cases of the occurrence of that ammoniacal phosphate, arising from the decomposition of the urea of the urine subsequent to its escape from the kidneys. Even in those few cases in which phosphate of lime is specially mentioned, it is described usually as mixed up with the other phosphates, and always as occurring in the amorphous or granular, and never in the crystalline state ; further, no peculiar importance is attached to it, as contrasted with the magnesian phos- phate. * Disease of the Lungs, Heart, and Aorta. 2nd edition, page 151. 282 Even one of the most recent writers on the urine gives the following description of the physical characters of deposits of phosphate of lime in urine : — " Deposits of phosphate of lime," he states, " as usually occurring in the urine, and mixed with magnesia, are always white and amorphous, under the microscope appearing in granules, sometimes of a greenish tinge, which exert a refracting action upon light. Crystallized deposits of this substance have not been ob- served" I now propose to show, first, that there is a crystalline deposit, the crystals composing which will be described hereafter, which does really consist of phosphate of lime ; second, that it is of frequent occurrence in human urine ; and third, that it is of greater patho- logical importance than the deposits of triple phosphate. I would first remark that I have for years been acquainted with the fact of the occurrence of crystalline phosphate of lime in the urine, and I have referred to it in ' The Lancet' of 1853, and also elsewhere. I should now remark, however, that the statement made by me as to the composition of the crystals, has hitherto been based upon their qualitative analysis only, and therefore was not so com- pletely conclusive and satisfactory as could be desired. Until recently I had not made any quantitative analyses ; these I have since been enabled to perform, and I now furnish the results of the chemical examination of four samples of the deposit. First Sample. — Filtered from the urine of twenty-four hours ; mixed, as ascertained in the first instance by means of the microscope, with a very minute quantity of triple phosphate. Bibasic phosphate of magnesia 0*15 Bibasic phosphate of lime T85 2-00 Second Sample. — Filtered from urine after the lapse of a day or two ; mixed with a small quantity of triple phosphate. Bibasic phosphate of magnesia 0*47 Bibasic phosphate of lime 6' 18 6-65 Third Sample. — From urine of twenty-four hours, after the lapse 283 of several days. Admixed with much triple phosphate, as shown first by the microscope, and afterwards by the chemical analysis. Bibasic phosphate of magnesia 4 '30 Bibasic phosphate of lime 5'4 1 971 Fourth Sample. — Separated from six ounces of fresh urine. De- posit very pure. Bibasic phosphate of lime 1 '96 No phosphate of magnesia. Now the admixture of the phosphate of magnesia in the first three samples was due solely to the fact that the phosphate of lime, deposited at first in the pure state, was allowed to remain in the urine until decomposition had commenced, and the phosphate of magnesia and ammonia had, in consequence, become formed. De- posits of phosphate of lime are sometimes contaminated from the same cause with carbonate and oxalate of lime. These analyses are therefore conclusive as to the composition of this earthy phosphate. In order to show that no error has been committed in them, I here append the process adopted. That the deposit in question really consisted of a phosphate, was first repeatedly determined by the action of a solution of nitrate of silver ; the crystals when touched with this reagent assumed a bright golden yellow colour. After having been separated and washed in distilled water, the phosphate was ignited to free it from animal matter, urea, &c., and weighed. It was then dissolved in hydrochloric acid; ammonia was added until a permanent precipitate formed ; this was redissolved by the addition of acetic acid. First the lime was preci- pitated from the solution by oxalate of ammonia, and afterwards the magnesia as follows : chloride of ammonium was added, then ammonia in slight excess, and lastly, phosphate of soda. The oxalate of lime formed was converted into carbonate of lime in the ordinary manner, and the phosphate of ammonia and magnesia into the pyro-phosphate of magnesia ; these were then weighed separately, and the amounts of the bibasic phosphate of lime were determined by the usual calcu- lations. The results obtained corresponded very closely with the original weights of the ignited phosphates subjected to analysis. The VOL. X. X 284 analyses, therefore, show that the crystallized phosphate of lime is a tribasic phosphate containing two atoms of lime, and most probably one of water. Form of the Crystals. The size, form, and arrangement of the crystals of phosphate of lime, as they occur in human urine, vary greatly, but the peculiarities are in all cases sufficiently characteristic to allow of the ready iden- tification of this phosphate by means of the microscope. The crystals are either single or aggregated, most frequently the latter, forming glomeruli or rosettes, more or less perfect (figs. 1, 2, 3). Sometimes they are small and needle-like, and then they frequently form by their crossing and union at right angles, glomeruli or sphe- rules (fig. 3). Sometimes the crystals are thin and flat, having oblique Fig. 1. Fig. 2. Fig. 3. Fig. 4. or pointed terminations (fig. 2). Very frequently, however, they are thick, and more or less wedge-shaped, and united by their narrow extremities so as to form more or less complete portions of a circle (fig. 1) ; the free larger ends of the crystals are usually somewhat oblique, and the more perfect crystals present a six-sided facette. I have never yet met with these crystals having both ends perfect, owing, I believe, to the tendency which they have to crystallize from a centre 285 in rosettes. The principal modifications which I have met with in the size, form, and arrangement of these crystals, are well shown in the eleven drawings which accompany this communication*. When these crystals are kept in the dry state for a long time, they not unfrequently break down and crumble into powder. The late Dr. Golding Bird, in his work on ' Urinary Deposits/ has given a representation of some crystals which he has denominated " penniform" describing them as consisting of a variety of the mag- nesian phosphate ; the crystals figured do, however, undoubtedly represent a modification of those of phosphate of lime. They are represented in figure 4, taken from Dr. Bird's original specimen. Although I have elsewhere pointed out this error, most recent writers on the urine still persist in describing these crystals as a variety of the phosphate of ammonia and magnesia. On the Frequency of their Occurrence. I find, as already stated, that phosphate of lime in the form of crystals is of much more frequent occurrence in human urine than the triple phosphate, excluding those cases of the presence of the latter phosphate which are due to the decomposition of the urea of the urine subsequent to its emission. I have met with deposits of crystallized phosphate of lime in some hundreds of urines, and in many different cases; it is therefore not a little remarkable, from the frequency of its occurrence and the peculiarities presented by the crystals, that it should have been so long overlooked. The micro- scope therefore furnishes us in most cases with the ready means of detecting the presence of deposits of phosphate of lime, as of so many other urinary deposits. Characters of Urine depositing Crystallized Phosphate of Lime. The urine from which phosphate of lime is deposited is usually pale, but occasionally it is high-coloured ; the quantity passed is large, and the calls to void it frequent, more or less uneasiness and smart- ing being occasioned by its passage, at the neck of the bladder and along the course of the urethra : its specific gravity varies greatly ; taking the whole quantity passed in twenty-four hours, it is usually below the average, nevertheless the animal matter and urea are * The Figures on the preceding page represent selected portions of four of these drawings : all the objects are magnified 100 diameters. 286 absolutely in excess. It is generally feebly acid, often decidedly so when first voided, the greater part of the phosphate of lime becoming deposited while the urine still retains some degree of acidity ; it however speedily becomes alkaline, owing probably to the excess of mucus contained in it. Sometimes the crystals of phosphate of lime are thrown down from the urine before its escape from the bladder ; ordinarily, however, the urine is bright and clear when passed, and the crystals are not formed until some time after it has been voided. In collecting this phosphate for analysis, the object being to procure it in as pure a state as possible and as free from phosphate of ammonia and magnesia, oxalate and carbonate of lime, it should be separated from the urine very soon after it has become deposited, and before decomposition has had time to set in. On the Pathological Importance of Deposits of Phosphate of Lime in Human Urine. Of the pathological importance of excess of phosphate of lime in the urine not a doubt can be entertained, but certain reasons and facts may be advanced to show that deposits of that phosphate have a deeper pathological significance than those of the phosphate of ammonia and magnesia. The proof of this is the more necessary, since writers on the urine are in the habit of describing, as well as of treating, deposits of the earthy phosphates collectively, and without distinguishing between them : this course was natural enough so long as they were unacquainted with the fact that deposits of phosphate of lime in the state of crystals are of frequent occurrence, or so long as they mistook them for a variety of the ammonio-magnesian phos- phate. One reason why we should be disposed to attach greater importance to the excess of the calcareous than the magnesian phos- phate, is that most of the phosphoric acid of this last phosphate, and all the magnesia, is derived from without, being contained in the various articles consumed as food ; while for the phosphate of lime, we have in the system — in the teeth and bones, and also in the nitrogenous tissues — sources containing some pounds weight of this phosphate. That the osseous system is subject to disintegration is certain, and that the extent and rapidity of this differ remarkably in different cases is equally so. This is shown by the simple fact alone of the 287 early and rapid decay of the teeth in many persons. For this general reason therefore only, we should, a priori, be disposed to attach greater importance to the occurrence of deposits of phosphate of lime than those of phosphate of magnesia. Other facts tending to confirm this view are, first, that while deposits of phosphate of lime are frequently met with, those of phosphate of magnesia (not the ammonio-magnesian phosphate) are •exceedingly rare ; and second, that the calcareous is of more difficult solubility than the magnesian phosphate. This last circumstance explains probably why phosphate of lime falls as a deposit from acid urine, while phosphate of magnesia remains in solution. The particular or special reasons for regarding deposits of phos- phate of lime as of more moment than those of the triple phosphate, are derived from direct pathological observation. I have observed that when this deposit occurs, it is very apt to be persistent ; and when it has disappeared, to return whenever the health is reduced from any cause. I have also noticed that, when it is persistent, it is usually associated with marked impairment of the health, and this often where organic disease does not exist. The prominent symptoms in one case of calcareous phosphatic deposit which I have had under observation for some years, were, — great disorder of the digestive or- gans, frequent and distressing headaches, occasional vomiting, debility, emaciation, great irritability of the nervous system, sexual powers weak, pulse slow and feeble, skin cold, urine in excess, of rather low specific gravity, acid when passed, but soon becoming alkaline, mic- turition frequent, with irritation at neck of bladder and in the course of the urethra : teeth much decayed. It should be stated that there is in this case a very slight tendency to paralysis of the right leg, as shown by an occasional sensation of coldness in the limb, and slight deficiency of power in it at times only. This symptom is, however, by no means a constant or necessary one in such cases. If these views of the pathology of phosphate of lime be correct, we should expect to find an excess of that phosphate in the urine in great and rapid waste of tissue, during the rapid decay of the teeth, and in cases of mollities ossium. That there is an excess of the calcareous phosphate in the urine in these cases, is shown alike by observation and analysis. It is obvious from this imperfect sketch that much remains to be 288 effected in regard to the pathology of phosphate of lime ; but now that the frequency of its occurrence in human urine as a crystallized deposit is made known, its pathology, apart from that of the triple phosphate, will no doubt be specially considered. It will be apparent from the following quotation, that the late Dr. Golding Bird regarded deposits of phosphate of lime as of more consequence than those of the triple phosphate : — " The pathological state of the system accompanying the appearance of deposits of phosphate of lime is analogous to that occurring with the triple phosphate ; indeed, as has been already observed, they often, and in alkaline urine always, occur simultaneously. So far as my own ex- perience has extended, when the deposit has consisted chiefly of the calcareous salt, the patients have appeared to present more marked evidence of exhaustion, and of the previous existence of some drain on the nervous system, than when the triple salt alone existed, unless its source is strictly local." It should be remembered that these remarks of Dr. Bird refer to deposits of phosphate of lime in the granular state, and not to the crystalline deposits, with the occurrence of which he was unacquainted. I have already stated that, according to my experience, the granular calcareous phosphatic deposits are much more rare than the crystalline. It follows from these observations and investigations : — First. That deposits of crystallized phosphate of lime are of fre- quent occurrence in human urine, much more so, indeed, than those of the amorphous or granular form of that phosphate. Second. That the crystals present well-marked and highly charac- teristic forms, whereby the identification of this phosphate by means of the microscope is rendered easy and certain. Third. That there is good reason to believe that deposits of phos- phate of lime are of greater pathological importance than those of the phosphate of ammonia and magnesia. February 2, 1860. Sir BENJAMIN C. BRODIE, Bart., President, in the Chair. In accordance with notice given at the last meeting, the Right Ho- nourable Sir Edward Ryan, Member of Her Majesty's Privy Council, 289 was proposed for election and immediate ballot ; and the ballot having been taken, Sir Edward Ryan was declared duly elected. The following communications were read : — I. " On the Saccharine Function of the Liver." By GEORGE HARLEY, M.D., F.C.S., Professor of Medical Jurispru- dence in University College, London. Communicated by Dr. SHARPEY, Sec. U.S. Received December 19, 1859. Although it is nearly 200 years since our countryman, the cele- brated Dr. Thomas Willis, made the important discovery of the occasional presence of sugar in the human urine, it was not, until very recently, known that the formation of saccharine matter is con- stantly going on in the healthy animal body. Since Bernard, in 1848, communicated to the French Academy the discovery of the saccharine function of the animal organism, physiologists hi all countries have more or less directed to it their attention. For a time various opinions were held by different ob- servers regarding the origin of the sugar found in the body ; but at length it was generally admitted that the liver had the power of forming a substance to which Bernard gave the name Glucogen ; that this peculiar substance was transformed into sugar ; and that the sugar in its turn disappeared in the capillaries of the different organs and tissues of the body. In the summer of 1858, however, Dr. Pavy read a paper on the "Alleged Sugar-forming Function of the Liver" before the Royal Society, the object of which was to prove that the presence of sugar in the animal economy is " due to a post mortem occurrence," — that as long as life continues, glucogen only is to be found, and not until after death does the transformation of this substance into sugar begin. The question of the saccharine function of the liver being a sub- ject to which I have more or less directed my attention since 1853, when I communicated to the Socie'te' de Biologic de Paris an account of an experimental procedure whereby diabetes can be produced artificially in animals, the above-mentioned paper was to me one of peculiar interest. The conclusions of the author were so much op- posed to the results of my own experiments, as well as those of other observers, that I felt anxious to test them. 290 Accordingly, having received the kind offer of Professor Sharpey's cooperation, I undertook a series of experiments, the results of which I beg the honour of communicating to the Royal Society. As the experiments performed were merely a repetition of some of those made by previous inquirers, I shall not enter into detail further than is necessary to explain the precautions adopted with the view to avoid error. And, looking at the object in view, it will readily be understood why in the present instance the tests employed for the detection of the sugar were limited to caustic potash with and without sulphate of copper. The mode of proceeding was as follows : — In testing the blood, a quantity of distilled water, equal to about four times that of the blood used, was boiled in a capsule. To the water, when boiling, were added a few drops of acetic acid, and afterwards the blood was very gradually introduced. In order that the albumen might be thoroughly coagulated, a drop or two more of acetic acid was added, care being taken to avoid an excess. When the albumen was completely coagulated, which was known by its separating and floating in the clear liquid, the whole was thrown on a filter. The clear filtered liquid was then tested. The same pro- cess was followed when operating on the liver. The first point to be ascertained was whether, under favourable circumstances as regarded diet, sugar could be found in the circula- tion. The following experiment proved this. Exp. 1. From the carotid artery of a rough terrier dog, three hours after being fed on bread, milk, and boiled liver, a portion of blood equal to about three-fourths of an ounce was withdrawn. This, on being treated in the manner explained, gave distinct evidence of the presence of sugar. A second portion of blood, after standing thirty-five minutes in a room of moderate temperature, yielded a similar re&ult. As in this instance a few seconds elapsed between the withdrawal of the first portion of blood and its treatment with the boiling acidu- lated water, and as it was possible that in these few seconds the sugar might have been formed from the glucogen present in the circulation, we (Professor Sharpey and myself) thought it advisable in our next experiment to allow the blood to flow directly from the artery into the boiling mixture, and thereby avoid the possibility of sugar being pro- duced by the transformation of glucogen after the removal of the blood 291 from the body. It was further desired to operate on an animal in what might be considered its natural condition as to food. Accord- ingly one that had been running at large was selected, and the following experiment performed : — Exp. 2. Into the left carotid artery of a small cocker dog was inserted a canula with a stopcock. The animal was then placed so as to allow the blood to flow directly into the boiling acidulated water. The clear filtered liquid from this blood became of a yellow tint on being boiled with soda, and gave a red precipitate with the sulphate of copper and potash, thereby indicating the presence of sugar. Two ounces of blood from the same animal were similarly tested after the blood had stood twenty-four hours in a room of moderate temperature, and the result obtained was the same as with the first portion. The next experiment was made on an animal under conditions, as regards food, unfavourable for the production of sugar. In order, too, to avoid any chance of injuring the sympathetic nerve during the operation, and thereby favouring the formation of sugar in the body, the blood was withdrawn from the right femoral artery instead of the carotid. The following are the particulars of the experi- ment : — Exp. 3. A good-sized dog was fed solely on flesh during four days. Three hours after the last meal, which consisted of half a pound of boiled horseflesh, 1^ oz. of blood was permitted to flow from the femoral artery directly into the boiling mixture. The solution obtained from this blood, as in the other cases, contained sugar. Another portion of blood, after standing three hours, was tested in the same way, and, as far as could be judged by the eye, contained a similar proportion of sugar. In neither of the preceding cases was the amount of sugar in the blood quantitatively determined, as I had already done so on many previous occasions ; and I knew that in healthy arterial blood it varied according to the state of the digestion, and the kind of food, from an inappreciable quantity up to 0'24 percent.* Having been now satisfied that sugar is to be found in the blood of healthy animals at the very moment of its withdrawal from the * " On the Physiology of Saccharine Urine," by Geo. Harley, M.D., British and Foreign Med. Chir. Rev. July 1857, p. 191-204. 292 circulation, even when none has been introduced along with the food, we next proceeded to test the grounds upon which it had been asserted that glucogen is not transformed into sugar in the healthy liver during life. In the paper already referred to, Dr. Pavy stated that the sudden abstraction of heat from the liver after its removal from the body, checks the transformation of the sugar-forming material, and thereby enables us to operate on the hepatic substance while in the same chemical condition as during life. The plan he recommends is to sacrifice a dog by pithing, and instantly to slice off a piece of liver, and throw it into a freezing mixture of ice and salt. In which case he says the absence of sugar is almost complete, and thence con- cludes that the presence of sugar in the liver can no longer be looked upon as a ( ' natural ante mortem condition ; " but " is in reality due to apost mortem occurrence." In the following experiments, not only was the plan recommended most scrupulously followed, but even the risk of the glucogen in the liver becoming transformed into sugar during the process of pre- paring the decoction, was avoided by cutting the frozen liver into thin slices, and allowing them, while still in that condition, to fall directly into the boiling mixture of acetic acid and water. The liver was in this way prevented from thawing until it entered a medium as capable of arresting the transformation of its glucogen into sugar as the cold. The decoction so obtained might therefore be presumed to contain the soluble matters as nearly as possible in the same chemical state as they were in the living organ. Exp. 4. A small, but full-grown dog was fed during fourteen days solely on animal food. Four hours after a meal of boiled horseflesh he was killed by section of the medulla oblongata. The abdomen was rapidly opened, and a portion of liver cut off and instantly immersed in a freezing mixture of ice and salt. A second portion of liver was as speedily as possible detached, and quickly washed in cold water. The latter portion was then, without loss of time, cut into fragments, which were allowed to fall directly into boiling acidulated water. On testing the clear filtrate, distinct evi- dence of the presence of sugar was obtained. After half an hour, the frozen portion of liver was taken, without being allowed to thaw, and sliced directly into the boiling water with acetic acid. The 293 clear liquid yielded in this case as distinct evidence of sugar as in the other. Forty minutes after the death of the animal, another portion of liver, which till then had remained undisturbed in the abdomen, was treated like the others. This gave evidence of containing a much greater quantity of sugar, thus confirming Bernard's statement, that the transformation of glucogen goes on in the liver after its removal from the body, or after the death of the animal. In order to be perfectly certain that the sugar found in the liver at the instant of its removal from the body was really formed where it was found, and not carried there by the portal blood from the food, the following experiment was performed : — Exp. 5. A dog was fed during ten days on boiled tripe. Twenty- two hours after the last meal the animal was pithed. In less than twenty seconds a portion of the liver was in the freezing mixture of ice and salt. While I boiled directly another portion of liver, Professor Sharpey put a ligature on the portal vein, and collected its blood. He likewise collected some of the hepatic blood which flowed from the cut liver. In the portal blood not a trace of sugar could be detected. The hepatic blood, on the other hand, gave distinct evidence of its presence. Both bloods were tested exactly alike. The clear liquids obtained from the frozen liver and from the portion treated directly, notwithstanding that they were filtered while hot, and also tested while still hot, both gave distinct evidence of sugar. On the follow- ing day a second portion of portal blood, which had been purposely kept all night in order to ascertain if, on standing some time, sugar would form in it, still yielded the same negative result. Even after treating it with saliva, which would have transformed its glucogen into sugar, had it contained any, no evidence of the presence of sugar was obtained. On the other hand, when saliva was added to the decoctions of the liver above spoken of, a great increase in the amount of sugar was observed. The quantity of sugar so obtained did not appear to be so great, however, as that yielded by a portion of the liver which remained all night untouched in the abdomen of the animal. Professor Garrod, F.R.S., who was present, not at the commence- ment of the experiment, but on the following day, when the different decoctions were tested, agreed with Professor Sharpey and myself, 294 that this experiment showed the truth of Bernard's statement, that the liver might contain both sugar and glucogeri when the portal blood contained neither. The stomach and intestines of this animal were found void of food ; the large intestine only contained fsecal matter. For the sake of still further assurance that the sugar found in the liver was neither due to some accidental cause, nor immediately de- rived from food, we determined to deprive an animal of food for some days before examining the liver. The following experiment was accordingly performed : — Exp. 6. A very large and powerful dog, in admirable condition, was subject to a rigid fast for seventy-two hours — three full days. Immediately after death, by section of the medulla oblongata, a por- tion of the liver was sliced off and immersed in ice and salt. Blood was then collected from the following sources : — 1st. From the portal vein. 2ndly. From the liver (t. e. blood which flowed from the liver when a portion of it was sliced off). 3rdly. From the right side of the heart. 4thly. From the aorta. 5thly. From the inferior vena cava. Although these bloods were all treated in a similar manner, and tested with the same quantities of copper and soda, yet none of them gave unequivocal evidence of the presence of sugar, except that from the liver. The blood from the right side of the heart gave doubtful evidence. At first sight it may appear strange that the blood from the right side of the heart should contain scarcely an appreciable quantity of sugar, while that of the liver showed its presence very obvi- ously ; but this no doubt arose from the hepatic blood being in great part prevented from reaching the heart : 1st, on account of most of it escaping into the abdomen, when the portion of liver was cut off ; and 2ndly, on account of its flow being in great measure arrested by the ligature of the portal vessels. All the bloods, except the hepatic, seemed to be free of glucogen as well as sugar ; for none of them, with that exception, gave any evidence of its presence after being treated with saliva in the usual way. On examination of the frozen liver (after three hours), which, as 295 in the other cases, was not allowed to thaw before being put into boiling water, the decoction was found to reduce the copper readily. On opening the stomach, nothing was found in it except some neutral mucus. The intestines were equally destitute of food, and in the rectum only a very small quantity of faeces was found ; so there could be no doubt as to the animal being in a fasting con- dition. The only point now remaining, was to determine quantitatively the increase in the amount of sugar in the liver after its removal from the body, and for that purpose we preferred operating on an animal fed on a mixed diet. Exp. 7. A small dog, which had been previously fed on animal diet, received a full meal of bread and milk. Five hours afterwards the animal was pithed, and a portion of the liver rapidly sliced off and immersed in a freezing mixture. A ligature was placed on the portal vein, and its blood collected before the circulation had ceased. On examination, this blood was found to contain a small quantity of sugar, derived no doubt from the food. Bernard, I believe, has erred in supposing that all the saccharine matter found in the animal organism is formed out of the glucogen produced in the liver. This, no doubt, is the case in the carnivora when the diet is restricted to food inconvertible into sugar in the alimentary canal, but cannot be regarded as the natural state of things either in the omnivora or herbivora ; for the food of the latter not only contains sugar, but its amylaceous elements may be converted into that substance in the process of digestion. The sugar found in the bodies of animals fed on a mixed diet ought therefore to be regarded partly as the direct product of the food, and partly as derived from the glucogen formed in the liver. Bernard's chief argument against this view is founded on the fact that the livers of dogs fed on a mixed diet contain no more sugar than those fed on purely animal food. In my opinion, however, this fact is not sufficient to decide the question ; for, as the liver does not store up sugar, the quantity it at any time contains is no criterion of the amount produced in it. Moreover, the sugar de- rived from the food need not be expected to be found in the liver. Had Bernard gauged the sugar present in the blood, instead of that 296 in the liver, after each kind of diet, the result obtained would, I be- lieve, have led him to a different conclusion. This being a point of great practical importance in the treatment of diabetes, I may be here permitted to mention that I have occasionally found nearly twice as much sugar in the blood of an animal on a mixed, than in that of one feeding on a purely flesh diet. To return to the last experiment. About two hours after the death of the animal, portions of the frozen part of the liver, and of that which had been kept warm in the body of the animal, were carefully weighed, and the proportions of sugar they respectively contained estimated by volumetric analysis. The portion of frozen liver was found to contain 0*333 per cent., and that of the other 1*55 per cent, of saccharine matter. It is thus seen that in two hours the sugar in the liver had augmented nearly fivefold. As Bernard has shown, the simple washing out of the liver by passing a stream of water through its vessels, would remove all the sugar anteriorly formed. On placing it again aside for a short time, a fresh portion of sugar would form in it at the expense of glucogen. 0-333 per cent, of sugar seems a small quantity ; but if we suppose a liver weighing, as in man, not less than 50 oz., to contain 0*333 per cent., above 70 grs. of sugar would be present in it at the moment of death, — no very insignificant quantity, when it is recol- lected that sugar is removed from the liver with every pulsation of the heart, to be partly consumed, and that it is as continually sup- plied by the organ. The results of the experiments now related do not therefore in any way countenance the notion that sugar is not produced in the healthy animal body. On the contrary, such conclusions as they afford are altogether in favour of the generally received views upon the subject. From the preceding experiments the following conclusions may be drawn : — 1st. Sugar is a normal constituent of the blood of the general circulation. 2ndly. Portal blood of an animal on mixed diet contains sugar. 3rdly. Portal blood of a fasting animal, as well as of an animal fed solely on flesh, is devoid of sugar. 297 4thly. The livers of dogs contain sugar, whether the diet is animal or vegetable. Sthly. Under favourable circumstances, saccharine matter may be found in the liver of an animal after three entire days of rigid fasting. 6thly. The sugar found in the bodies of animals fed on mixed food is partly derived directly from the food, partly formed in the liver. 7thly. The livers of animals restricted to flesh diet possess the power of forming glucogen, which glucogen is at least in part trans- formed into sugar in the liver ; — an inference which does not exclude the probability of glucogen (like starch in the vegetable organism) being transformed into other materials besides sugar. 8thly. As sugar is found in the liver at the moment of death, its presence cannot properly be ascribed to a post mortem change, but is to be regarded as the result of a natural condition. II. " Hereditary Transmission of an Epileptiform Affection accidentally produced." By E. BROWN-SEQUARD, M.D. Communicated by Dr. SHARPEY, Sec. E.S. Received December 23, 1859. It is well known that the number of facts which seem to prove that an accidentally produced affection may be transmitted by parents to their offspring is still small, and that serious objections have been raised against most, if not all, the facts of this kind. The following observations seem to show peremptorily that, at least in one species of animals, this kind of transmission may occur. I have shown that certain injuries to the spinal cord, in Guinea- pigs and other Mammals, are followed, after a few weeks, by a con- vulsive disease, very much like epilepsy. Fer several years it has been frequently observed that the young of a number of those epi- leptic animals, which I kept in my laboratory, were at times attacked with epileptiform convulsions. For many months I have made regular observations on this curious subject, and I have ascertained, by careful watching, that six young guinea-pigs which had frequent attacks of convulsions, were the offspring of one male and two female 298 guinea-pigs rendered epileptic in consequence of an injury to the spinal cord. This observation derives its importance chiefly from the fact that, if epilepsy is an affection which naturally exists among guinea-pigs, it must be very rare, as I have never seen it except in the progeny of individuals operated upon and rendered epileptic; and yet the number of healthy guinea-pigs that I have kept for months is really immense. It seems therefore that we can conclude, from these observations, that epilepsy, or an affection which very much resembles it, may be transmitted from parents to offspring, even when it has been accidentally produced in one of the parents, — at least in one species of animals. February 9, 1860. Sir BENJAMIN C. BRODIE, Bart., President, in the Chair. The Right Honourable Sir Edward Ryan was admitted into the Society. The following communications were read : — I. "On the Resin of the Ficus rubiginosa, and a new Homo- logue of Benzylic Alcohol." By WARREN DE LA RUE, PhJ)., F.R.S., and HUGO MILLER, Ph.D., F.C.S. Com- rnunicated by Mr. DE LA RUE. (Abstract.) In this communication the authors give an account of a new alcohol homologous with benzylic alcohol (Cu H8 O2) which they have found occurring in the state of a natural acetic ether in the exudation from an Australian plant known as the Ficus rubiginosa. This acetic ether, for which they propose the name of Acetate of Sycoceryl, constitutes about 14 per cent, of the crude resin ; the re- mainder consisting principally of an amorphous resin which they name Sycoretin. The different degree of solubility of the various constituents in alcohol, afforded the means of the separation of the one from the other ; none of them present any remarkable properties except the 299 new ether ; so that the authors have devoted their attention mainly to the working out of the chemical relations of this substance. Acetate of sycoceryl, having very characteristic properties, could be readily obtained in beautiful crystals ; but some difficulty oc- curred in obtaining it absolutely pure, on account of the presence of a parasitical body which accompanied it constantly in solution, and always crystallized upon it. At last means were found of removing the latter substance by dissolving out the acetate of sycoceryl with ether. The per-centage composition of this parasitical body was found to be — Carbon 76'56 Hydrogen 12'30 Oxygen 11-24 but it existed in too small a quantity to admit of its true chemical relations being made out. Acetate of sycoceryl gave on analysis the following per-centages as the mean result of two accordant analyses : — Carbon 79*09 Hydrogen 10-28 Oxygen 10'63 These numbers agree well with those required by the formula C40 H32 O4 based upon experimental evidence. Acetate of sycoceryl, when acted upon by sodium-alcohol, yielded acetic acid and a beautiful crystalline body resembling caffeine or asbestos ; this proved to be a new member of the benzylic alcohol series having the composition C36 H30 O2, which requires the following per-centage quantities : — Mean of two analyses. Carbon 82-44 82-39 Hydrogen 11-45 11-38 Oxygen 6-11 6-23 The authors, by acting with chloride of benzoyl on sycocerylic alcohol, obtained the corresponding benzoate of sycoceryl ; and by employing chloride of othyl (acetyle), have prepared the acetate of sycoceryl which was identical with the original crystalline constituent of the resin. By treating sycocerylic alcohol with nitric acid, an acid was pro- cured which appears to be sycocerylic acid. VOL. x. y 300 The products of the action of chromic acid on sycocerylic alcohol , were a white crystalline neutral substance and a body crystallizing in large flat prisms. The latter appears to be the sycocerylic aldehyde. II. " Analytical and Synthetical Attempts to ascertain the cause of the differences of Electric Conductivity discovered in Wires of nearly pure Copper " By Professor WILLIAM THOMSON, F.R.S. Received December 22, 1859. Five specimens of copper wire No. 22 gauge, out of a large number which had been put into my hands by the Gutta Percha Company to be tested for electric conductivity, were chosen as having their conductivities in proportion to the following widely different numbers, 42, 71*3, 84*7, 86'4, and 102 ; and were subjected to a most careful chemical analysis by Professor Hofmann, who at my request kindly undertook and carried out what proved to be a most troublesome investigation. The following report contains a statement of the re- sults at which he arrived : — ''Royal College of Chemistry, March 10th, 1858. "SiR, — I now beg to communicate to you the results obtained in the analysis of the several varieties of copper wire intended for the use of the Transatlantic Telegraph Company, which you forwarded to me for examination. " I have limited the inquiry to a minute qualitative analysis of the wires, to a very accurate determination of the amount of copper, and an approximative determination of the amount of oxygen. The qualitative analysis has been repeated several times with as consider- able quantities as the amount of material at my disposal permitted. The quantitative determinations of fche. copper have been made with particular care, and after a lengthened , scrupulous inquiry into the limit of accuracy of which the method employed is capable, I am convinced that the true per-centages of copper cannot be more than (H per cent, either above or below the means of the determinations, the details of which I give you in the Appendix. " The following Table contains the results furnished by analysis : — 301 Conductivity of the wire, in relative measure*. 42. '"• ' 84-7. 86-4. 102. ( Qualitative analysis 4 Copper. Iron. Nickel. Arsenic. Oxygen. Copper. Iron. Nickel. Oxygen. Copper. Iron. Nickel (doubtful). Oxygen. Copper. Iron. Nickel (doubtful). Oxygen. Copper. Iron. Oxygen. Per-centage of copper 9876 99-20 99-53 99-57 99-90 Amount of impurities. 1-24 0-80 0-47 0-43 0-10 100-00 100-00 100-00 100-00 100-00 " Since it appeared probable that the extraordinary difference in the conductivity of the several specimens was due rather to non-metallic impurities than to metallic admixtures, careful experiments were made in every case for the detection of sulphur. In none of the specimens was it possible to discover the slightest trace of sulphur. Qualitative experiments having established on the other hand the presence of oxygen, probably in the form of suboxide of copper in every one of the specimens, an attempt was made to ascertain the quantities by determining the loss which the wire after rolling suffered when heated in an atmosphere of hydrogen, and by simultaneously estimating the quantity of water formed. " In this experiment, the details of which are given in its Appendix, the following numbers were obtained : — Conductivity 42 71'3 | 847 [86-4 I 102 Percentage of Oxygen 0-087 0-119 | 0-172 | 0-159 | 0-193 " Unfortunately the same reliance cannot be placed upon these numbers as upon the preceding ones, since the method employed involves many sources of error, and want of material precluded the possibility of repeating the experiments. " From the preceding analysis, it is obvious that the amount of impurities in the several specimens examined is small, varying as it does between O'lO and 1'24 per cent. The number of foreign * I have since found 10"9X 131f as the factor to reduce from this to absolute measure. Thus the conductivities of the five specimens are respectively 55*2, 95-3, 111-4, 113-6, 134-1, in terms of one one thousand millionth of the British absolute unit. — W. T. Y2 302 constituents also is comparatively small. I should, however, state that the analytical results which I have given do not exclude the presence of exceedingly minute quantities, even of other metals which might have been detected if larger quantities of copper could have been submitted to analysis. Some years ago, Max Duke of Leuch- tenberg* examined the black precipitate formed at the anode in the electrotype process, during the decomposition of sulphate of copper by the galvanic current. In this precipitate, of which considerable quantities accumulate by the gradual solution of large quantities of copper passing through the process, he found the following consti- tuents : — Antimony 9 -22 Arsenic 7'40 Platinum O44 Gold 0-98 Silver 4-54 Lead . 0-15 Iron 0-30 Nickel 2-26 Cobalt 0-86 Vanadium 0'64 Tin 33-50 Copper 9-24 Oxygen 24*82 Sulphur 2-46 Selenium 1'27 Sand .. 1-90 " Of these constituents, the ten first metals were obviously derived from the copper, in which they could have been scarcely detected unless by this accumulative process. Of the remainder of the con- stituents, the tin in a great measure is derived from the solderings. " The results obtained in the analysis of the copper wires which you forwarded to me, appear to establish one fact in a satisfactory manner, viz. that the diminution of conductivity observed in certain specimens of copper is due to the presence in these specimens of a certain amount of foreign matter, and not, as it has been supposed, to a peculiar change in the physical condition of the metal ; for in the specimens analysed the conductive power rises in the same order as the total amount of impurities diminishes. " I have, &c., (Signed) "A. W. HOFMANN." "Professor William Thomson, F.R.S., fyc." It appears therefore that in the case of these four specimens, the electric conductivity is in order of purity of the copper ; but yet that only extremely small admixtures of other substances are to be found even in those which have but half the conductivity of the best. * Petersburg!! Acad. Bull. vii. p. 218. 303 On the other hand, I have found by experimenting on artificial alloys, that comparatively large admixtures of lead, iron, silver, and zinc seem to produce sometimes improvement, sometimes little or no sensible influence, and sometimes (as in the case of zinc) an injurious effect on the conductivity of specimens of pure electrotype copper from which the alloys were made. The largeness of the proportion of other metal required to produce any considerable deterioration in comparison with that of the whole amount of impurities which Pro- fessor Hofmann's investigation demonstrates in specimens of low quality as to conductivity, is worthy of remark, and seems to indicate that this low quality must be due to other than metallic impurities. The great difference between the conducting qualities of two spe- cimens of electrotype copper, from which two series of alloys were separately prepared, seems also to indicate some as yet undiscovered cause, as operative in general. I am assured by Messrs. Matthey and Johnson, by whom all the alloys were prepared, that similar methods were followed and equal care bestowed to ensure purity in the two cases. The results of my measurements of conductivity are shown in the following Tables :— TABLE I. — Two Series, Nos. 1-10 and Nos. 1-32, of Specimens prepared by Messrs. Matthey and Johnson from pure electro- type copper, and the same alloyed with other metals, as spe- cified. o c5 £& Specification of compound. Specific conducti- vity. i SERIES I. Pure copper 138*5 2 Pure copper alloyed with P25 per cent, silver 138-5 3 Pure copper alloyed with '13 per cent, silver 139.5 4 Pure copper alloyed with -25 per cent, lead 144 5 Pure copper alloyed with '13 per cent, lead 146 6 Pure copper alloyed with -25 per cent, tin 131 7 Pure copper alloyed with '13 per cent tin 133 8 Pure copper alloyed with '80 per cent, zinc 125 9 Pure copper alloyed with *40 per cent zinc 1205 10 Pure copper alloyed with 1 -40 per cent, zinc . . . 10.3 304 T A BLE I . — continued. Specification of compound. Specific conducti- vity. SERIES II. 397-5 copper+2'5 silver 9987 copper4- 1'3 silver 997-5 copper +2-5 lead 998-7 copper +1-3 lead 997-5 copper 4- 2-5 tin 998-7 copper + 1-3 tin 99 9 copper 4- 1 silver 999copper+l lead 999 copper -f -5 lead-f-5 silver Equal parts of 1 and 3...., 997-5 copper +2-5 iron 998-7 copper +1-3 iron 1000 copper +2-5 protoxide of copper 1000 parts of 3 & 4- 2-5 protoxide of copper (too brittle to test) 1000 parts of 4 &4-2'5 protoxide of copper 997.5 copper 4-2'5 zinc 995 copper +2-5 lead 4-2-5 zinc 995 copper+2-5 lead-|-2-5 iron 998-7 parts of 11 + 1-3 lead 997-5 parts of 11 4-2-5 zinc 998-7 parts of 11 + 1-3 zinc 997 parts of 11 + 1-3 lead &4-1-3 zinc 992 copper 4-8 zinc 996 copper 4*4 zinc 986 copper 4-14 zinc 982 copper 4~ 18 zinc 994 copper -j-6 zinc 980 copper4-20 aluminium 990 copper 4- 10 aluminium 995 copper 4-5 aluminium 997 copper+3 aluminium Pure copper, from whtch all the above were made 69-8 117-7 94-5 105-8 91-6 116-9 126-7 134-2 128-0 89-3 129-7 113-7 122-5 119-7 108-9 85-1 131.5 135-0 77-6 95-2 117-6 118-9 117-0 80.2 102-3 109-5 44-0 128-7 122-5 130-2 120-9 TABLE II. — First Series (10 specimens) arranged in order of conductivity. ° 1 o P* £v Specification of compound. Specific conducti- vity. 5 Pure copper alloyed with -13 per cent of lead 146 4 Pure copper alloyed with "25 per cent, of lead . . 144-5 3 Pure copper alloyed with '13 per cent of silver 139-5 2 Pure copper alloyed with "25 per cent, of silver 138-5 I 138-5 7 133 6 Pure copper alloyed with "25 per cent, of tin . . 131 g Pure copper alloyed with '80 per cent, of zinc 125 9 Pure copper alloyed with "40 per cent, of zinc 120-5 10 Pure Conner alloved with 1'40 per cent, of zinc .., 103 305 TABLE III. — Second Series (32 specimens) arranged in order of conductivity. Specification of compound with manufacturers' description of mechanical quality of wire. 19 9987 of No. 11 + 1-3 lead: fair 135-0 8 999 copper-j-1 lead: fair 134-2 18 995 copper-|-2-5 lead +2-5 iron: very good 131-5 31 997 copper -f3 aluminium : good 130-2 11 997-5 copper-f-2-5 iron : not very good 1297 29 990 copper 4- 10 aluminium: good 1287 9 999 copper + -5 lead+-5 silver : rather better than No. 8 128-0 7 999copper+l silver: fair 1267 13 1000 copper-f-2-5 protoxide of copper : very bad 122-5 30 995 copper-f-5 aluminium : very good 122-5 32 Pure copper : very good 120-9 15 1000 of No. 4+2-5 protoxide of copper : better than No. 14, but not good 1197 23 992 copper + 8 zinc: first-rate alloy 118-9 2 998-7 copper + 1 -3 silver : fair, but rather frangible 1 177 22 997-5 of No. 11 + 1-3 lead+1-3 zinc : very good indeed 117'6 24 996 copper+4 zinc : moderately good 117'0 6 998-7 copper-)- T3 tin : perhaps not quite as good as No. 5 ... 116-9 12 9987 copper+1 -3 iron: frangible 1137 27 994 copper+6 zinc : good 109-5 16 997-5 copper+2-5 zinc : first-rate alloy 108-9 4 998-7 copper 1 -3 lead : rather better than No. 4 105-8 26 982 copper, 18 zinc : very good 102-3 21 9987 of No. 11 + 1-3 zinc: very fair 95-2 3 997-5 copper+2-5 lead : good, but requires care 94-5 5 997*5 copper+2'5 tin : much the same as Nos. 3 and 4 91 -6 10 Equal parts of Nos. 1 and 3 : bad, frangible 89-3 17 995 copper+2-5 lead+2-5 zinc : very good 85-1 25 986 copper +14 zinc: first-rate alloy 80-2 20 997-5 of No. 11 +2-5 zinc: very fair 77'6 1 997-5 copper 2-5 silver : fair, but rather frangible 69-8 28 980 copper+20 aluminium : not very good 44-0 14 1000 parts of No. 3+2*5 protox. copper; almost undrawable (too brittle to test). Specific conducti- vity. The alloys numbered 14 and 15 were prepared with a view to testing the possible effect of a suboxide of copper mixed or com- bined with the mass. Although they do not seem worse than others of nearly the same metallic composition, it cannot be considered that they demonstrate that oxygen exercises no influence, as the portion of oxide introduced may have been reduced in the melting ; and indeed it is quite possible that some accident in the melting may possibly give rise to oxidation to a greater or less degree, and may cause some of the irregularities and uncertainties which have been observed. On this I may remark, that although I have found that no mechanical alteration by hammering, twisting, &c. produces any considerable 306 effect of the conductivity of one piece of solid copper, I have not yet found whether or not specimens either good or bad retain their specific qualities after melting. I may add, that it will be of great importance to ascertain the laws of variation of conductivity with temperature, of different specimens of nearly pure copper differing largely in conductivity. I have hitherto used standards of copper wire in all the relative determina- tions of conductivity which I have made for different commercial specimens and artificial alloys of copper ; and before I found the very large differences of conductivity shown in this and in my pre- ceding communication to the Royal Society (June 15, 1857), it seemed natural to suppose that the relation between specimen and standard would remain constant, or nearly constant, when the tem- peratures of the two are varied to the same extent. Now, however, it seems scarcely probable that this can be the case, and a rigorous experimental examination of the influence of temperature becomes necessary. P.S. April 11, 1860. — I append the following extract from evidence which I gave on examination before the Government Com- mittee on submarine telegraphs on the 17th December, 1859, as it bears directly on the subject of the preceding article, and shows what degree of weight may in my opinion be attached to the syn- thetical attempts which have been described. (Chairman.) Question 2458. Soon after you became a Director of the Atlantic Telegraph Company, was your attention directed to the conductivity of copper ? — Yes. 2459. You instituted a series of experiments, did not you, to deter- mine the variation of this quality in different samples of copper ? — A number of samples of copper were, at my request, put into my hands for the purpose of measuring their conductivity in consequence of my having accidentally noticed differences greater than I expected in the conducting power of one or two samples which I had had previously. 2460. Will you be good enough to state the general results at which you ultimately arrived, arid your modes of experimenting ? — My modes of experimenting did not differ materially from the methods which had been followed by certain other experimenters, 307 especially in Germany, and were in reality all based on Professor Wheatstone's invention of a beautiful method for comparing re- sistances, to which I have frequently referred as Professor Wheat- stone's electric balance. 246 1 . What were the results at which you arrived ? — That dif- ferent specimens chosen at random from the stock supplied for manufacture differed immensely in conducting power. 2462. Although nominally the same quality of copper? — Yes, although nominally the same quality of copper. All those specimens of wire were supposed to be of the very best quality, the only copper supposed to be good being that which admitted of being drawn into wire suitably for the purpose. A good mechanical quality was ne- cessary to prevent frequent fractures in the wire-drawing ; and to un- derstand that, I should say that hanks in unbroken lengths amount- ing to a large mass were always required, the worse metal being found to break before it could be drawn into a hank of a certain size. The mechanical qualities seem to have been satisfactory, but no sus- picion whatever was entertained that there were also large differences in electric conducting power. W. Weber had many years before pointed out considerable differences in different specimens of copper wire which he had tested. I found differences much exceeding those, and I did not, as I expected, find any approximation to a uniform average among the different specimens tested ; some spe- cimens I found nearly double in their conducting power, compared with others, reckoned according to the weight and length, allowing for the variations of gauge. Calling the best specimen which I had in the summer of 1857, 100, I found many specimens standing at 60 in specific conductivity, many standing at 50, many standing at 80, a few above 90 ; and so far as I can recollect, the average of a large number of specimens that I then examined may have stood between 60 and 70, but I consider the statement of such an average to be of no value, it is so much a matter of chance. If I had re- ceived a dozen specimens of a low quality below the average, or if I had chanced to receive a dozen specimens of a higher quality, the average would have been so much the lower or the higher. I never had an opportunity of measuring the conductivity of 200 or 300 miles of submarine cable ; such alone would have given me exact in- formation as to the average for that portion of cable. I may men- 308 tion that a month or two later, still in the summer of 1857, I re- ceived specimens of wire which were in stock for submarine tele- graphs,— for some of the Mediterranean telegraphs, I believe, — which stood as low as 43 on that scale ; and, lastly, I may mention that I have since met with specimens standing 2 or 3 per cent, above the 100 ; and an artificial alloy, which I had prepared, stood, so far as I can estimate, as high as 111. 2463. What was that alloy? — The alloy consisted, so far as I can recollect, of copper and *13 per cent, of lead. I have made experi- ments upon a series of alloys, in all about 43 or 44, and have re- cently repeated the examination so as to arrive at accuracy, within certain limits ; and I expect, immediately, to be able to communicate to the Royal Society, for publication, the results. A few months ago I sent a provisional list of the specimens, showing the relative conductivity of those alloys, but, possibly, requiring correction as to the absolute conductivity stated. That list was communicated to Mr. Latimer Clarke, and, I believe, a copy of it was laid before the Committee. 2464. (Professor Wheatstone.) "Were you quite certain that you employed pure copper in your experiments ? — I could not be quite certain. 2465. The copper might be alloyed with other things than metals ; is it not very probable that it might contain some suboxide, and that the mixing of lead afterwards with it might have reduced the suboxide, and therefore have given it a higher conducting power on that account ? — That is possible. I cannot say that I am at all satisfied that the experiments which I have made point out distinctly the relation between the ascertained chemical combination and con- ductivity. I may mention that one of my alloys was made with a suboxide melted with the copper ; but the uncertainty of the pro- cess of melting the suboxide and the uncertainty as to how much of the oxidation may have disappeared in the melting, prevented me from attributing much weight to the experiment. 2466. (Chairman.) What was the result with that alloy; was it a low result, or a high result ? — A moderate result ; not a low result. 2467. But not a high one ? — A somewhat high result ; but I may mention that in one series the highest conductivity was found with a mixture of lead and iron ; fractions of a per cent, of lead, and 309 fractions of a per cent, of iron mixed with pure copper gave a higher conductivity than a nominally pure copper, with which the alloys were prepared. I must mention further, that in two series the alloys, both prepared by Messrs. Matthey and Johnson, and as I have been assured with equal care, gave results presenting considerable discre- pancies ; the conductivity of the pure copper in the first stood high, nearly agreeing with the 100 of my first scale, the pure copper of the second series fell considerably below that limit. On this account it appears that even pure copper, carefully prepared by the electro- type process, does not always give us results which show perfectly in point of conductivity ; but to make such experiments in a satisfactory manner, it would be necessary to have a thorough chemical investi- gation, both synthetical and analytical, of the metals used ; such a thorough investigation I have not been able to carry out, in conse- quence of the large expense which it would entail. I may mention that Mr. Matthiessen has gone through a series of experiments on alloys, of which the chemical composition has been ascertained with all possible accuracy, and has, I believe, arrived at highly important results relative to electrical conductivity. I have been in communi- cation with him, and have supplied him with a specimen of one of my standards. He mentions to me that he has obtained specimens conducting better to a considerable extent than the 100 of my first scale. In that respect he has confirmed what I have myself ascer- tained, having myself found specimens as high as 1 1 1 on that scale. A number of alloys of definite chemical composition, prepared with great care by Mr. Calvert of Manchester, and already tested by him for thermal conductivity and for mechanical properties, have been put into my hands, in order that I may measure their electric con- ductivities. I hope soon to be able to obtain and publish results for this series of alloys. III. " On a new Method of Substitution ; and on the formation of lodobenzoic, lodotoluylic, and lodanisic Acids." By P. GRIESS, Esq. Communicated by DR. HOFMANN. Re- ceived January 3, 1860. In a previous notice* I have pointed out the existence of a new class * Proceedings of the Royal Society, vol. ix. p. 594. 310 of nitrogenous acids which are generated by the action of nitrous acid on the amidic acids of the benzoic group, the change consisting in the substitution of one equivalent of nitrogen for three equivalents of hydrogen in two molecules of the amidic acid. Two eqs. benzamic New acid, acid. Under the influence of various agents these new acids undergo remarkable changes, amongst which the transformation produced by the mineral acids deserves to be particularly noticed. If the acid C28 Hu N3 O8 be gently heated with strong hydrochloric acid, nitrogen gas is evolved, the yellow colour of the original acid disappears, and a red body separates, which may be separated by filtration and purified by treatment with animal charcoal. Both the physical properties and the analysis of the substance thus obtained, prove it to be pure chlorobenzoic acid. The hydrochloric mother-liquor on evaporation deposits crystals of the hydrochlorate of benzamic acid. C28 Hn N3 08 + 2HC1= C14 (H5 Cl) O4 + CM (H5 H2 N) O4, HC1 + N2. To render intelligible this transformation, the acid C28 Hn N3 O8 may be viewed as a double acid corresponding to two molecules of water, C14(H8N'a)Oa 1 Cu (H4 H2 N) 02 X04=C14 (H4 N'2) O4 + CU (H5 H2 N) 04, and splitting under the influence of hydrochloric acid into the two groups C14(H4N'2)O4 and C14( H5 H2 N) O4, in the first of which the two equivalents of monatomic nitrogen are replaced by hydro- chloric acid, producing C14(H5C1)O4, while the second simply com- bines with hydrochloric acid, producing hydrochlorate of benzamic acid. It deserves to be mentioned that the acid C28 Hu N3 O8 may be derived also from two equivalents of hydrated oxide of ammo- nium, when its formula assumes the following shape : — [(C14H402)2"N"'HN2]" Further experiments are necessary to decide which of these two formulse deserves the preference. 311 lodobenzoic Acid, C14(H5I)O4. This substance is produced by a process similar to that which furnishes the chlorobenzoic acid, viz. by the action of hydriodic acid on the acid C28 Hu N3 O8, — beautiful white plates resembling benzoic acid, easily soluble in alcohol and in ether and difficultly soluble in water. lodobenzoic acid is remarkable for its great stability ; even fuming nitric acid fails to expel the iodine, and transforms the substance simply into nitro-iodobenzoic acid. The silver salt of iodobenzoic acid is a white amorphous precipitate con- taining CM (H4 1 A g) 04. lodotoluic Acid, C16 (H7 1)O4. This acid is formed from the analogous nitrogenous acid in the toluic series, according to the equation It crystallizes in white plates of a pearly lustre, which in their che- mical and physical properties are very similar to iodobenzoic acid. lodanisic Acid, C16 (H7 1) O6 is obtained by the action of hydriodic acid upon the nitrogenous acidC32H15N3012, C32H15N3012+H2I2=C16(H7I)06 + C16(H7H2N)06,HH-N, Exceedingly small, nearly white needles, almost insoluble in boiling water, very soluble in alcohol and in ether. The new method of substitution, by which the described products were obtained, although less direct than the ordinary processes, promises nevertheless to adapt itself to several cases of special interest. I am at present engaged in pursuing these experiments, with the view of producing fluo- and cyano-benzoic acids and their homologues, which have never been obtained. The experiments which I have described were performed in Pro- fessor Hofmann's laboratory. 312 February 16, 1860. Sir BENJAMIN C. BRODIE, Bart., President, in the Chair. The following communications were read : — I. "Description of an Instrument combining in one a Maxi- mum and Minimum Mercurial Thermometer, invented by Mr. JAMES HICKS." By BALFOUR STEWART, Esq. Com- municated by J. P. GASSIOT, Esq. Received Feb. 7, 1860. About a fortnight since, Mr. James Hicks, the intelligent foreman of Mr. L. P. Casella, Optician, called at Kew Observatory with an instrument of the above description, for the purpose of having it compared with the ordinary maximum and minimum thermometers. This comparison proving very satisfactory, and the principle of the instrument commending itself to Dr. Robinson, Mr. Gassiot, Pro- fessor Walker, and several other scientific men who examined it, Mr. Gassiot requested me to write a short description of it, whinh he thought might be of interest to tbe Royal Society. For many particulars of this description, I am indebted to Mr. Casella and Mr. Hicks, who furnished me with details regarding the construction of the instrument. Its chief advantage consists in its furnishing us with a mercurial minimum thermometer, no serviceable instrument of this description having hitherto been made. At the same time it is also capable of being used as a mercurial maximum thermometer. The principle of the instrument is briefly as follows : — It has a cylindrical bulb nearly 3^ inches long and half an inch in diameter, filled with mercury. This gives a bore nearly -^th of an inch wide, and a scale on which 1° Fahr. corresponds to about -^th of an inch. "When the graduation has reached 150° Fahr. or so, both the tube and the scale are made to assume a position at right angles to that which they occupied previously, so that the first portion of the thermometer being vertical, the second will be horizontal. The numbers on the horizontal scale are not, however, in continuation of those on the vertical ; for in the instrument from which this account is taken, while 150° is the highest division on the vertical scale, the first on the horizontal is —10°, the next 0°, the 3rd 10°, and so on. The reason of this method of graduation will immediately appear. 313 Above the mercury there is a small quantity of spirits of wine, which extends some distance into the horizontal tube. The quantity of this, and the graduation, correspond in such a manner, that the extreme end of the spirit column denotes the same degree of tem- perature as the mercury. The remainder of the horizontal tube is filled with air. There are two moveable indices in the spirit column, one in the vertical tube, the other in the horizontal, each about half an inch long. The former, B, consists of a fine steel magnet enclosed in glass. This forms the body of the index. At either extremity there is a head of black glass, similar to that which occurs in the index of an ordinary minimum thermometer. A fine hair is tied round the neck of this index, between the body and the upper head ; and it is made to hang down by the side, so that by its elastic pressure against the tube, the index may be kept in its place, notwithstand- ing its verticality. The index in the horizontal tube A, is in all respects similar to that of an ordinary minimum thermometer. Let us now suppose the instrument fixed in its position, the first part of the stem being vertical. In order to adjust it, we must first bring the vertical index into contact with the upper ex- tremity of the mercurial column. To do this, let us take two small but strong horseshoe magnets, and lay the one above the other, so that the poles of the one shall overlap to a small extent the cor- responding poles of the other. Bring the magnets up to the index in such a manner, that, while the poles of the one bear against the side of the glass tube, the overlapping poles shall lie over the tube so as to be in front of the index : the index will now follow the motion of the magnets, and it may thus be brought down to the surface of the mercury. In order to bring the horizontal index to the extremity of the spirit column, all that is necessary is to incline the horizontal tube a little downwards by pressing on the end. . 314 The indices being DOW set and the instrument in adjustment, let us suppose the temperature to rise ; the mercurial column will push the vertical index up, but this index will remain in its place when the mercury again falls, and will therefore denote the maximum temperature reached. On the other hand, let us suppose the tem- perature to fall. The mercury in falling is followed by the spirit column propelled by the air behind it. The spirit column, again, will, on its edge coming in .contact with the end of the horizontal index, draw the index with it into a position, where it will remain when the mercury again rises. This index will therefore register the extreme minimum point which the. spirit column has reached ; but by the principle of graduation, this will correspond with the mini- mum point reached by the mercurial column. Let us now suppose that a small portion of the spirit column has become separated, and lodged itself in the extremity of the tube. The principle of graduation will immediately enable us to discover this, by a want of correspondence being produced in the readings of the mercurial and of the spirit column. If, for instance, before the separation, the mercury read 50°, and the horizontal extremity of the spirit column also 50°, it is clear that, after the abstraction of spirits has taken place, the horizontal column will read lower. "We have thus a check upon this possible source of error, which we have not in the ordinary minimum thermometer. Indeed, it is to all intents a mercurial minimum thermometer that we are now de- scribing, the spirits serving merely as a vehicle for the indices. It will be remarked, that were both columns capable of acting in a hori- zontal position, there would be no necessity for the bend, and the instrument would be more portable ; but in this position it is found that there is danger of the spirits becoming mixed with the mercury, and thus interfering with the action of the instrument. Should this ever be brought about by travelling, or any other cause, a smart jerk or two of the instrument will join the separated columns and put all right. The instrument is thus constructed : — The vertical tube, including the bulb, is first made and filled with mercury to the proper height, and the magnetic index is introduced ; then the horizontal tube is joined, and the spirits of wine and the horizontal index are introduced. The bulb is then placed in a freezing mixture, in order that the 315 mercury may retreat as far as possible, followed by the spirits of wine. The tube is then sealed, care being taken that the bore shall end in a small rounded chamber ; for if pointed, some of the spirits would be apt to lodge there, whence it would be difficult to remove it. The object of cooling the bulb before sealing off, is that we may have as much air in the tube as possible ; for its pressure, as already mentioned, enables the spirits to follow the mercury when the latter falls. To graduate the instrument, set it with the mercurial stem hori- zontal in melting ice, then point off the extremity of the mercurial, and also of the spirit column as corresponding to 32° Fahr. Perform a similar operation in water at 42°, 52°, 62°, &c., and also in freezing mixtures down to zero, or lower if necessary. In conclusion, if used as a wet-bulb thermometer, this instrument will give us the maximum and minimum temperatures of evaporation obtained under precisely the same circumstances. II. " On the Expansion of Metals and Alloys." By F. CRACE- CALVERT, Esq., F.R.S., and G. CLIFF LOWE, Esq. Com- municated by Mr. CALVERT. Received December 1, 1859. [Abstract.] One of us having been engaged for some time in investigating several of the properties of pure metals, it was thought desirable to take advantage of having pure metals at our disposal, together with a series of definite alloys of those metals, to determine their rate of expansion. And we were encouraged in pursuing this course of investigation, by finding that several of the authors who had pre- viously published tables of the expansion of metals differed widely in their results. These discrepancies, having reference to some of the metals most extensively used, might, we thought, be due either to the method employed, or to the fact that metals of different de- grees of purity had been experimented upon. Therefore, being sure of the purity of the metals that we intended to employ, we had recourse to a method the accuracy of which we trust will appear satisfactory. Owing to the difficulty of obtaining the metals in a pure state in large quantities, we found it necessary to employ square bars, having VOL. x. z 316 a length of 60 millimetres by 10 millimetres of diameter. We therefore devised a process to determine with accuracy the expansion of such short bars. This, we believe, we have effected, as our appa- ratus will easily indicate an expansion amounting to the 50,000th of an inch, or about the 2000th part of a millimetre. Omitting the description of our apparatus and of the details of our operations, which would be long for this abstract of our results, we give here a Table of the general results obtained with the fol- lowing metals : — Mean for 100° C. Divisions of the scale read off in 25,000ths of an inch in a rising tempe- rature from 10° to 90°. Divisions of same scale read off in cooling from 90° to 10°. calculated from these means and corrected for ex- pansion of ves- sel, &c., by deducting 20. 1st. 2nd. 3rd. Mean. 1st. 2nd. 3rd. Mean. Cadmium '174 171 172 172-3176 173 172 173-7 196-2 Lead '155 L56 157 156 161 160 159 160-0 177-5 Tin 142 142 145 143 147 148 147 147-3 161-5 Aluminium . . . . 120 1?,0 120 1?,0 122-5 121 1?? 121-8 131-1 Forged zinc 119 121 120 120 120 119 120 119-7 129-8 Silver 110 109 109-5 1 OP-5 111-5 110 110 110-5 117-5 Copper (pure) cast 106 105-5 106 105-8 103 103-5 107 104-5 111-4 Copper (pure) 1 hammered... J 99 99 99 99 101 99 100 100 104-4 Gold 81 80-5 80-7 81-5 81 81-3 81-3 Bismuth 78 77 77-5 77-5 81-51 80 80 80-5 78-8 Wrought iron 69 72 73 71-3 73-5 72 72-5 72-7 70-0 Cast iron ... 67 68-5 68-5 68-0 68 70-5 70-5 69-7 66-1 Steel (soft) 66-5 62-0 63 63-8 66-5 65 66-5 66 61-1 Antimony ... . 63 6? 62-5 63 62 62-5 58-1 Platinum 57-5 57-5 58 58-0 52-2 From the above observations we deduce the following Table of coefficients of linear expansion from 0° to 100°: — Cadmium (pure) 0-00332 Lead (pure) .. .. .. .. 0-00301 Tin (pure) 0-00273 Aluminium (commercial) ... . . 0*00222 Zinc, forged (pure) 0-00220 Silver (pure) 0-00199 Gold (pure) 0*00138 Bismuth (pure) 0-00133 Wrought iron 0-00119 317 Cast iron Steel (soft) Antimony (pure) Platinum (commercial) 0-00112 0-00103 0-00098 0-00068 On comparing these coefficients with those found by previous ex- perimenters, we find that they agree very closely in those cases where commercial metals have been employed. But when we come to those metals which we employed in a pure state, such as lead, tin, zinc, silver, copper, bismuth, antimony, cadmium, and gold, we find a marked difference, which we attribute to our experiments having been made with pure metals ; and we are confirmed in this view by several series of experiments made with impure or commercial metals. We give in our paper several series of experiments which prove that, as for conductibility of heat by bodies, their molecular condi- tion exercises the greatest influence on their expansion. For ex- ample, we have found that the same bar of steel gives, according to its degree of tempering, the following ratios of expansion : — Raising temperature from 10° to 90°. Cooling temperature from 90° to 10°. Mean calculated and corrected for a bar 60 mm. for 100°. 1st. 2nd. 3rd. Mean. 1st. 2nd. 3rd. Mean. Steel bar as pur- "1 chased / Ill 112 111-5 111-5 113 113 115 113-7 64-6 Steel bar at ] maximum of I softness J 107 108 107-5 107-5 107 112 111 110 62-5 Same bar at~| maximum of >• hardness J 141 145 140 142 138 139 139 138-7 84-0 The influence of the molecular state of bodies is also clearly illus- trated in the class of compounds or carbonates of lime; — Chalk Lithographic stone Stalactite Marble Rates of expansion from 0° to 100°. 19'6 45-0 67-0 71-0 318 Influence of Crystallisation. Crystallization influences the expansion of bodies as it does their power to conduct heat ; thus, the same zinc cast horizontally or ver- tically has not only a different crystallized structure, but also expands in a different ratio. Raising temperature 10° to 90°. Cooling temperature 90° to 10°. Mean for 100° less correc- tion. 1st. 2nd. 3rd. 4th. Mean. 1st. 2nd. 233 193 3rd. Mean. Zinc cast vertically Zinc cast hori- 1 xo n tally J 224 187 226 186-5 227 187 226 226 186-8 232 190-5 234 192-5 233 192 266-9 216-7 We have also examined the ratio of expansion in several series of alloys made in multiple and definite proportions, but shall give here only one series as illustrating our results. Copper and Tin. 10° to 90°. Mean for 100° less cor- rection. Mean for 100° less correction. 1st. 2nd. 3rd. Mean. 1st. 2nd. 3rd. Mean 5Sn 90-27 1 ICu 9-73 J 127 124 124 125 136-2 129 124 126-5 138-1 4Sn 88-141 Cu 11-86J 122 122 122-0 132-5 127 126 126-5 138-1 3Sn 84-791 Cu 15-21 f 119 119-5 119-2 129-5 123 122 123-5 122-8 133-5 2Sn 78-79 Cu 21-21 118 118 118 127-5 117 117 117 126-2 Sn 65-02 : Cu 34-98 109-5 111-5 110-5 118-1 110-5 110-5 110-5 118-1 Sn 48-17 2Cu 51-83 111-0 111 111 118-7 113-5 112 112-7 120-8 Sn 34-21 3Cu 61-79 112 111 111-5 119-3 113 112 112-5 120-6 Sn 31-73 ' 4Cu 68-27 102 105 103-5 109-3 106 105 105-5 111-8 Sn 27-10 5Cu 72-90 104 104 104 110 106 106 106 112-5 Sn 15-68 lOCu 84-32 101 101 101 106-2 101 101 101 106-2 Sn 11-031 15Cu 88-97 J 95 94-5 94-7 98-3 94-5 95 94-7 98-3 Sn 8-511 20Cu 91-49 J 97 99-5 ...... 98-2 102-7 99 99 99 103-7 Sn 6-831 25Cu 93-1 7 J 99 99 99 103-7 100 00 100 105 319 February 23, 1860. Sir BENJAMIN C. BROUIE, Bart., President, in the Chair. The following communications were read : — I. " Measurement of the Electrostatic Force produced by a Daniell's Battery." By Professor WILLIAM THOMSON, F.ft.S. Received January 21, 1860. In a pnper " On Transient Electric Currents," published in the Philosophical Magazine for June 1853, I described a method for measuring differences of electric potential in absolute electrostatic units, which seemed to me the best adapted for obtaining accurate results. The "absolute electrometer" which I exhibited to the British Association on the occasion of its meeting at Glasgow in 1855, was constructed for the purpose of putting this method into practice, and, as I then explained, was adapted to reduce the indications of an electroscopic * or of a torsion electrometer to absolute measure. The want of sufficiently constant and accurate instruments of the latter class has long delayed my carrying out of the plans then set forth. Efforts which I have made to produce electrometers to fulfil certain conditions of sensibility, convenience, and constancy, for various objects, especially the electrostatic measurement of gal- vanic forces, and of the differences of potential required to produce sparks in air, under definite conditions, and the observation of natural atmospheric electricity, have enabled me now to make a beginning of absolute determinations, which I hope to be able to carry out soon in a much more accurate manner. In the meantime I shall give a slight description of the chief instruments and processes followed, and state the approximate results already obtained, as these may be made the * I Lave used the expression " electroscopic electrometer," to designate an electrometer of which the indications are merely read off in each instance by a single observation, without the necessity of applying any experimental process of weighing, or of balancing by torsion, or of otherwise modifying the conditions exhibited. VOL. X. 2 A 320 foundation of various important estimates in several departments of electrical science. The absolute electrometer alluded to above, consists of a plain metallic disc, insulated in a horizontal position, with a somewhat smaller plane metallic disc hung centrally over it, from one end of the beam of a balance. A metal case protects the suspended disc from currents of air, and from irregular electric influences, allowing a light vertical rod, rigidly connected with the disc at its lower end, and sus- pended from the balance above, to move up and down freely, through an aperture just wide enough not to touch it. In the side of the case there is another aperture, through which projects an electrode rigidly connected with the lower insulated disc. The upper disc is kept in metallic communication with the case. In using this instrument to reduce the indications of an electro- scopic or torsion electrometer to absolute electrostatic measure, the insulated part of the electrometer is kept in metallic communication with the insulated disc, while the cases enclosing the two instruments are also kept in metallic communication with one another. A charge, either positive or negative, is communicated to the insulated part of the double apparatus. The indication of the tested electrometer is read off, and at the same time the force required to keep the move- able disc at a stated distance from the fixed disc below it, is weighed by the balance. This part of the operation is, as I anticipated, somewhat troublesome, in consequence of the instability of the equi- librium, but with a little care it may be managed with considerable accuracy. The plan which I have hitherto followed, has been to limit the play of the arm of the balance to a very small arc, by means of firm stops suitably placed, thus allowing a range of motion to the upper disc through but a small part of its whole distance from the lower. A certain weight is put into the opposite scale of the balance, and the indications of the second electrometer are observed when the electric force is just sufficient to draw down the upper disc from resting in its upper position, and again when insufficient, to keep it down with the beam pressed on its lower stop. This operation is repeated at different distances, and thus no considerable error de- pending on a want of parallelism between the discs could remain undetected. It may be remarked that the upper disc is carefully ba- lanced by means of small weights attached to it, so as to make it hang 321 as nearly as possible parallel to the lower disc. The stem carrying it is graduated to hundredths of an inch ; and by watching it through a telescope at a short distance, it is easy to observe ToWth °f an ^nc^ of its vertical motion. 1 have recently applied this method to reduce to absolute electro- static measure the indications of an electrometer forming part of a portable apparatus for the observation of atmospheric electricity. In this instrument a very light bar of aluminium attached at right angles to the middle of a fine platinum wire, which is firmly stretched between the inside coatings of two Leyden phials, one occupying an inverted position above the other, experiences and indicates the electrical force which is the subject of measurement, and which consists of repulsions in contrary directions on its two ends, pro- duced by two short bars of metal fixed on the two sides of the top of a metal tube, supported by the inside coating of the lower phial. The amount of the electrical force (or rather as it should be called in correct mechanical language, couple} is measured by the angle through which the upper Leyden phial must be turned round an axis coincident with the line of the wire, so as to bring the index to a marked position. An independently insulated metal case, bearing an electrode projecting outwards, to which the body to be tested is applied, surrounds the index and repelling bars, but leaves free apertures above and below, for the wire to pass through it without touching it ; and by other apertures in its sides and top, it allows the motions of the index to be observed, and the Leyden phials to be charged or discharged at pleasure, by means of an electrode applied to one of the fixed bars described above. When by means of such an electrode the inside coatings of the Leyden phials are kept con- nected with the earth, this electrometer becomes a plain repulsion electrometer, on the same principle as Peltier's, with the exception that the index, supported by a platinum wire instead of on a pivot, is directed by elasticity of torsion instead of by magnetism ; and the electrical effect to be measured is produced by applying the electrified body to a conductor connected with a fixed metal case round the index and repelling bars, instead of with these conductors them- selves. This electrometer, being of suitable sensibility for direct comparison 2 A 2 322 with the absolute electrometer according to the process described above, is not sufficiently sensitive to measure directly the electro- static effect of any galvanic battery of fewer than two hundred cells with much accuracy. Not having at the time arrangements for working with a multiple battery of reliable character, I used a second torsion electrometer of a higher degree of sensibility as a medium for comparison, and determined the value of its indications by direct reference to a Darnell's battery of from six to twelve elements in good working order. This electrometer, in which a light aluminium index, suspended by means of a fine glass fibre, kept constantly elec- trified by means of a light platinum wire hanging down from it and dipping into some sulphuric acid in the bottom of a charged Leyden jar, exhibits the effects of electric force due to a difference of poten- tials between two halves of a metallic ring separately insulated in its neighbourhood, will be sufficiently described in another communi- cation to the Royal Society. Slight descriptions of trial instruments of this kind have already been published in the Transactions of the Pontifical Academy of Rome*, and in the second edition of Nichol's Cyclopaedia (article Electricity, Atmospheric), 1860. I hope soon to have another electrometer on the same general prin- ciple, but modified from those hitherto made, so as to be more convenient for accurate measurement in terms of constant units. In the meantime I find, that, by exercising sufficient care, I can obtain good measurements by means of the divided ring electro- meter of the form described in Nichol's Cyclopaedia. In the ordinary use of the portable electrometer, a considerable charge is communicated to the connected inside coatings of the Leyden phials, and the aluminium index is brought to an accurately marked position by torsion, while the insulated metal case surround- ing it is kept connected with the earth. The square root of the reading of the torsion-head thus obtained measures the potential, to which the inside coatings of the phials have been electrified. If, now, the metal case referred to is disconnected from the earth and put in connexion with a conductor whose potential is to be tested, the square root of the altered reading of the torsion-head required to bring the index to its marked position in the new circumstances measures similarly the difference between this last potential and that * Accademia Pontificia del Nuovi Lyncei, February 1857. 323 of the inside coatings of the phials. Hence the excess of the latter square root above the former expresses in degree and in quality (positive or negative) the required potential. This plan has not only the merit of indicating the quality of the electricity to be tested, which is of great importance in atmospheric observation, but it also affords a much higher degree of sensibility than the instrument has when used as a plain repulsion electrometer ; and, on account of this last-mentioned advantage, it was adopted in the comparisons with the divided ring electrometer. On the other hand, the portable electrometer was used in its least sensitive state, that is to say, with its Leyden phials connected with the earth, when the comparisons with the absolute electrometer were made. The general result of the weighings hitherto made, is that when the discs of the absolute electrometer were at a distance of twenty hundredths of an inch, the number of degrees of torsion in the port- able electrometer was 3-229 times the number of grains' weight required to balance the attractive force ; and the number of degrees of torsion was 7' 6 9 times the number of grains' weight found in other series of experiments in which the distance between the discs was thirty hundredths. According to the law of inverse squares of the distances to which the attraction between two parallel discs is subject when a constant difference of potentials is maintained between them *, the force at a distance of -^ of an inch would have been •TDT» according to the first of the preceding results, or, according to the second, .-g-l^ of the number of degrees of torsion. The mean of these is .-^j, or 1'2 ; and we may consider this number as represent- ing approximately the value in grains' weight at -^ of an inch distance between the discs of the absolute electrometer, correspond- ing to one degree of torsion of the portable electrometer. By com- paring the indications of the portable electrometer with those of the divided ring electrometer, and by evaluating those of the latter in terms of the electromotive force of a Dani ell's battery charged in the usual manner, I find that 284 times the square root of the number of degrees of torsion in the portable electrometer is approxi- mately the number of cells of a Daniell's battery which would pro- duce an electromotive force (or, which is the same thing, a difference * See § 11 of elements of mathematical theory of electricity appended to the communication following this in the ' Proceedings.' 3.24 of potentials) equal to that indicated. Hence the attraction between the discs of the portable electrometer, if at ^ of an inch distance, and maintained at a difference of potentials amounting to that produced by 284 cells, is 1-2 grain. The effect of 1000 cells would therefore be to give a force of 14 '9 grains, since the force of attraction is propor- tional to the square of the difference of potentials between the discs. The diameter of the opposed circular areas between which the attrac- tion observed took place, was 5'86 inches. Its area was therefore • 187 of a square foot, and therefore the amount of attraction per square foot, according to the preceding estimate for -^ of an inch distance and 1000 cells' difference of potential, is 79 '5 grains. To reduce the statement to consistent units founded on a foot as the unit of length, we may suppose, instead of j1-^ of an inch, the distance between the discs to be y-J-g- of a foot. We conclude that, with an electromotive force or difference of potentials produced by 1 000 cells of Daniell's battery, we find for the force of attraction 55*3 grains per square foot between discs separated to a distance of yj-jy of a foot, This result differs very much from an estimate I have made ac- cording to my theoretical estimate of 2,500,000 British electro- magnetic units for the electromotive force of a single element of Daniell's and Weber's comparison of electrostatic with electro-mag- netic units. On the other hand, it agrees to a remarkable degree of accuracy with direct observations made for me, during my absence in Germany, by Mr. Macfarlane, in the months of June and July 1856, on the force of attraction produced by the direct application of a miniature Daniell's battery, of different numbers from 93 to 451 of elements, applied to the same absolute electrometer with its discs at *079 of an inch asunder. These observations gave forces varying, on the whole, very closely according to the square of the number of cells used ; and the mean result reduced according to this law to 1000 cells was 23'4 grains. Reducing this to the distance yj^ of a foot, and dividing by '187, the area in decimal of a square foot, we find 54 '3 grains per square foot at a distance of yj-g- of a foot. Although the experiments leading to this result were executed with great care by Mr. Macfarlane, I delayed publishing it because of the great discrepance it presented from the estimate I deduced from Weber's measurement, which was published while my preparations 325 were in progress. I cannot doubt its general correctness now, when it is so decidedly confirmed by the electrometric experiments I have just described, which have been executed chiefly by Mr. John Smith and Mr. John Ferguson, working in my laboratory with much ability since the month of November. I am still unable to explain the discrepance, but it may possibly be owing to some miscalculation I have made in my deductions from Weber's result. Glasgow College, Jan. 18, 1860. POSTSCRIPT, April 12, 1860. I have since found that I had inadvertently misinterpreted Weber's statement in the ratio of 2 to 1. I had always, as it appears most natural to me to do, regarded the transference of nega- tive electricity in one direction and of positive electricity in the other direction, as identical agencies, to which in our ignorance as to the real nature of electricity we may apply indiscriminately the one expression or the other, or a combination of the two. Hence I have always regarded a current of unit strength as a current in which the positive or vitreous electricity flows in one direction at the rate of a unit of electricity per unit of time; or the negative or resinous electricity in the other direction at the same rate ; or (according to the infinitely improbable hypothesis of two electric fluids) the vitreous electricity flows in one direction at any rate less than a unit per second, and the resinous in the opposite direction at a rate equal to the remainder of the unit per second. I have only recently remarked that Weber's expressions are riot only adapted to the hypothesis of two electric fluids, but that they also reckon as a cur- rent of unit strength, what I should have called a current of strength 2, namely a flow of vitreous electricity in one direction at the rate of a unit of vitreous electricity per unit of time, and of the resinous electricity in the other direction simultaneously, at the rate of a unit of resinous electricity per unit of time. Weber's result as to the relation between electrostatic and electro- magnetic units, when correctly interpreted, I now find would be in perfect accordance with my own results given above, if the electro- motive force of a single element of the DanielPs battery used were 2,140,000 British electro-magnetic units instead of 2,500,000, as 326 according to my thermo-dynaruie estimate. This is as good an agree- ment as could be expected when the difficulties of the investigations, and the uncertainty which still exists as to the true measure of the electromotive force of the Daniell's element are considered. It must indeed be remarked that the electromotive force of Daniell's battery varies by two or three or more per cent, with variations of the solu- tions used ; that it varies also very sensibly with temperature ; and that it seems also to be dependent, to some extent, on circumstances not hitherto elucidated. A thorough examination of the electro- motive force of Daniell's and other forms of galvanic battery, is an object of high importance, which it is to be hoped will soon be at- tained. Until this has been done, at least for Daniell's battery, the results of the preceding paper may be regarded as having about as much accuracy as is desirable. I may state therefore, in conclusion, that the average electromotive force per cell of the Daniell's batteries which I have used, produces a diiference of potentials* amounting to '0021 in British electrostatic measure. This statement is perfectly equivalent to the following in more familiar terms : — One thousand cells of Daniell's battery, with its two poles connected by wires with two parallel plates of metal y^th of a foot apart and each a square foot in area, produces an electrical attraction equal to the weight of 55 grains. II. " Measurement of the Electromotive Force required to pro- duce a Spark in Air between parallel metal plates at dif- ferent distances." By Professor W. THOMSON, F.R.S. Received January 26, 1860. The electrometers used in this investigation were the absolute electrometer and the portable electrometer described in my last communication to the Royal Society, and the operations were ex- ecuted by the same gentlemen, Mr. Smith and Mr. Ferguson. The conductors between which the sparks passed were two unvarnished plates of a condenser, of which one was moved by a micrometer screw, giving a motion of -^- of an inch per turn, and having its * See §§ 10, 11 of Appendix to the following communication. 327 head divided into 40 equal parts of circumference. The readings on the screw-head could be readily taken to tenth parts of a division, that is to say, to ~^ of an inch on the distance to be measured. The point from which the spark would pass in successive trials being somewhat variable and often near the edges of the discs, a thin flat piece of metal, made very slightly convex on its upper surface like an extremely flat watch- glass, was laid on the lower plate. It was then found that the spark always passed between the crown of this con- vex piece of metal and the flat upper plate. The curvature of the former was so small, that the physical circumstances of its own elec- trification near its crown, the opposite electrification of the opposed flat surface in the parts near the crown of the convex, and the electric pressure on or tension in the air between them could not, it was supposed, differ sensibly from those between two plane conducting surfaces at the same distance and maintained at the same difference of potentials. The reading of the screw-head corresponding to the position of the moveable disc, was always determined electrically by making a succession of sparks pass, and approaching the moveable disc gra- dually by the screw until all appearance of sparks ceased. Contact was thus produced without any force of pressure between the two bodies capable of sensibly distorting their supports. With these arrangements several series of experiments were made, in which the differences of potentials producing sparks across differ- ent thicknesses of air were measured first by the absolute electro- meter, and afterwards by the portable torsion electrometer. The following Tables exhibit the results hitherto obtained. 328 TABLE I. — December 13, 1859. Measurements by absolute electro- meter of maximum electrostatic forces * across a stratum of air of different thicknesses. Area of each plate of absolute electrometer ='187 of a square foot. Distance between plates of absolute electrometer =^0 of a foot. * Electrostatic force, Length of spark in inches. Weight in grains required to ba- lance in absolute electrometer. Electromotive force in units of the electrometer. or electromotive force per inch of air, in tem- porary units. s. Vw. Vw s •007 •0105 6 9 2-4495 3-0000 349-9 285-7 •0115 10 3-1622 275-0 •014 13 3-6055 2575 •017 16 4-0000 2353 •018 19 4-3589 242-2 •024 30 5-4772 228-2 •0295 40 6-3245 214-4 •034 50 7-0710 208-0 •0385 60 7-7459 201-2 •041 70 8-3666 204-1 •0445 80 8-9442 201-0 •048 90 9-4868 197-6 •052 100 10-0000 192-3 •055 110 10-4880 190-7 •058 120 10-9544 188-9 •060 130 11-4017 190-0 These numbers demonstrate an unexpected and a very remarkable result, — that greater electromotive force per unit length of air is required to produce a spark at short distances than at long. When it is considered that the absolute electrification of each of the op- posed surfaces t depends simply on the electromotive force per unit length of the space between them, or, which is the same thing, the resultant electrostatic force in the air occupying that space, it is difficult even to conjecture an explanation. Without attempting to explain it, we are forced to recognize the fact that a thin stratum of air is stronger than a thick one against the same disruptive tension in the air, according to Faraday's view of its condition as trans- mitting electric force, or against the same lifting electric pressure from its bounding surfaces, according to the views of the 18th cen- * See § 3 below. f See § 4 below. 329 tury school, as represented by Poisson. The same conclusion is established by a series of experiments with the previously-described portable torsion electrometer substituted for the absolute electro- meter, leading to results shown in the following Table. TABLE II. — January 17, 1860. Measurements by portable torsion electrometer of electromotive forces producing sparks across a stratum of air of different thicknesses. Electrostatic force, Length of spark in inches. Torsion in degrees required to balance in electrometer. Electromotive force in units of the electrometer. or electromotive force per inch of air, in tem- s. 9. ve. porary units. v 0-^-s. '001 •002 3 7 1-732 2-646 1732 1323 •003 11 3-316 1105 •004 14 3-742 935 •005 18 4-243 849 •006 22 4-690 782 •007 27 5-196 742 •008 30 5-477 685 •009 33 5-744 638 •010 38 6-164 616 •Oil 43 6-557 596 •012 48-5 6-964 580 •013 54 7-348 565 •014 59 7-681 549 •015 66 8-124 542 •016 73 8-544 534 •017 79 8-888 523 •018 85 9-219 512 The series of experiments here tabulated stops at the distance 1 8 thousandths of an inch, because it was found that the force in the electrometer corresponding to longer sparks than that, was too strong to be measured with certainty by the portable electrometer, whether from the elasticity of the platinum wire, or from the rigidity of its connexion with the aluminium index being liable to fail when more than 85° or 90° of torsion were applied. So far as it goes, it agrees remarkably well with the other experiments exhibited in Table I., as is shown by the following comparative Table, in which, along with results of actual observation extracted from Table II., are placed results deduced from Table I. by interpolation for the same lengths of spark. 330 TABLE III. Experiments of December 13, 1859, and January 17. 1860, compared. Col. 1. Col. 2. Col. 3. Col. 4. Electromotive force Electromotive Length of spark in inches, s. per inch of air, Dec. 13, in tempo- rary units of that day. force per inch of air, Jan. 17, in tem- porary units of that day. Ratios of numbers in Col. 3. to numbers in Col. 2. s s •-. -' • •007 349-3 742 2-13 •0105 285-7 606 2-12 •0115 275-0 588 2-14 •014 257-5 549 2-14 •017 235-3 523 2-22 •018 242-2 512 2-11 Mean 2-14 The close agreement with one another of the numbers in Col. 4, derived from series differing so much as those in Cols. 2 and 3, and obtained by means of electrometers differing so much in con- struction, constitutes a very thorough confirmation of the remarkable result inferred above from the experiments of the first series, and shows that the law of variation of the electrostatic force in the air required to produce sparks of the different lengths, must be repre- sented with some degree of accuracy by the numbers shown in the last column of either Table I. or Table III. The following additional series of experiments were made on pre- cisely the same plan as those of Table II. 331 TABLE IV. — January 21, 1860. Measurements by portable torsion electrometer of electromotive forces producing sparks across a stratum of air of different thicknesses. Electrostatic force, Length of spark in inches. Torsion in degrees required to balance in electrometer. Electromotive force in units of the electrometer. or electromotive force per inch of air, in tem- s. 0. V0. porary units. •001 •002 3-2 6-4 1-79 2-32 1790 1160 •003 10-5 3-24 1080 •004 13-2 3-63 907 •005 14-2 3-77 754 •006 18-2 4-27 712 •007 21-7 4-66 666 •012 41-2 6-42 535 •013 46-7 6-83 525 •014 53-2 7-29 521 •015 57-2 7-56 504 •016 63-2 7-95 497 •017 68-2 8-26 486 •018 78-2 8-84 491 TABLE V. — January 23, 1860. Similar experiments repeated, s. e. V0. \/6>-=-s. •001 3-5 1-87 1870 •002 6-5 2-55 1275 •003 9-5 3-08 1027 •004 12-7 3-56 890 •005 15-5 3-94 788 •006 18-5 4-30 716 •007 23-0 4-80 686 •008 25-62 5-06 632 •009 30-5 5-52 613 •010 35-0 5-92 592 •Oil 39-5 6-28 571 •012 44-0 6-63 553 •013 50-0 7-07 544 •014 54-0 7-35 525 •015 59-0 7-68 512 •016 63-5 7-97 498 •017 695 8-34 490 •018 74-5 8-63 479 The difference between the numbers shown in these two Tables and in Table II. above, are probably due in part to true differences in the resistance of the air to electrical disruption; but variations in the electrometer, which was by no means of perfect construction, 332 may have sensibly influenced the results, especially as regards the differences between those shown in Table II. and those shown in Tables IV. and V., which agreeing on the whole closely with one another fall considerably short of the former. TABLE VI. Summary of results reduced to absolute measure. Col .1. Col. 2. Col. 3. Col. 4. Col. 5. Length of spark in inches. St Electrostatic forces ac- cording to simple deter- minations of Dec. 13, 1859. V<%lv./ 32-2X87T* Electrostatic forces according to estimated average of va- pious clctcmii~ Differ- ences. Pressures of electricity from either metallic surface balanced by air immediately before disruption, in grains weight per square foot t. s X5XV -187 n£ttions X2 =X. X. 8:rX32-2' •001 11480 162800 •002 8000 79080 •003 6840 57810 •004 5820 41820 •005 5090 ... 32010 •006 4700 27300 •007 4600 4530 + •0070 26200 •008 4200 21830 •009 3990 19690 •010 3860 18390 •0105 3760 3770 -•0010 17450 •Oil 3720 17130 •0115 3620 3630 -•0010 16200 •012 3550 15580 •013 3480 14970 •014 3390 3390 •oboo 14200 •015 3320 13580 •016 3260 13110 •017 3000 3140 -•0040 11800 •018 3190 3170 +•0020 12500 •024 3100 3000 11100 •0295 2820 2820 9830 •034 2740 2740 9250 •0385 2650 2650 8650 •041 2690 2690 8900 •0445 2650 2650 8640 •048 2600 2600 8350 •052 2530 2530 7910 •055 2510 2510 7770 •058 2490 2490 ... 7630 •060 2500 2500 7720 * Distance between discs of absolute electrometer — •£$ foot=£ inch. Area of each ='187 square foot. Force of gravity at Glasgow on unit mass =32-2 dynamical units of force; that is to say, generates in one second a velocity of 32 -2 feet per second. f This is most directly obtained by finding the force between the discs of the absolute electrometer per square foot, and reducing, according to the inverse proportion of squares of distances, to what it would have been if the distance between them had been equal to the length of the spark. 333 APPENDIX. In order that the different expressions, "potential," " electromotive force," "electrostatic force," "pressure of electricity from a me- tallic surface balanced by air," used in the preceding statement, may be perfectly understood, I add the following explanations and defini- tions belonging to the ordinary elements of the mathematical theory of electricity. 1. Measurement of quantities of electricity. — The unit quantity of electricity is such a quantity, that, if collected in a point, it will repel an equal quantity collected in a point at a unit distance with a force equal to unity. [In British absolute measurements the unit distance is one foot ; and the unit force is that force which, acting on a grain of matter during a second of time, generates a velocity of one foot per second. The weight of a grain at Glasgow is 32'2 of these British units of force. The weight of a grain in any part of the earth's surface may be estimated with about as much accuracy as it can be without a special experiment to determine it for the particular locality, by the following expression : — In latitude A average weight of a grain =32-088 X (1 + -005133 x sin2 x) British absolute units.] 2. Electric density. — This term was introduced by Coulomb to designate the quantity of electricity per unit of area in -any part of the surface of a conductor. He showed how to measure it, though not in absolute measure, by his proof plane. 3. Resultant electric force at any point in an insulating fluid. — The resultant force at any point in air or other insulating fluid in the neighbourhood of an electrified body, is the force which a unit of electricity concentrated at that point would experience if it exercised no influence on the electric distributions in its neighbourhood. 4. Relation between electric density on the surface of a conductor t and electric force at points in the air close to it. — According to a proposition of Coulomb's, requiring, however, correction, and first correctly given by Laplace, the resultant force at any point in the air close to the surface of a conductor is perpendicular to the surface and equal to 4iep, if p denotes the electric density of the surface in the neighbourhood. 5. Electric pressure from the surface of a conductor balanced by air. — A thin metallic shell or liquid film, as for instance a soap-bubble, 334 if electrified, experiences a real mechanical force in a direction per- pendicular to the surface outwards, equal in amount per unit of area to 2rcy>2, p denoting, as before, the electric density at the part of the surface considered. This force may be called either a repulsion (as according to the views of the eighteenth century school) or an attrac- tion effected by tension of air between the surface of the conductor and the conducting boundary of the air in which it is insulated, as it would probably be considered to be by Faraday ; but whatever may be the explanation of the modus operandi by which it is produced, it is a real mechanical force, and may be reckoned as in Col. 5 of the preceding Table, in grains weight per square inch or per square foot. In the case of the soap-bubble, for instance, its effect will be to cause a slight enlargement of the bubble on electrification with either vitreous or resinous electricity, and a corresponding collapse on being perfectly discharged. In every case we may regard it as constituting a deduction from the amount of air-pressure which the body experiences when unelectrified. The amount of this deduction being different in different parts according to the square of the electric density, its resultant action on the whole body disturbs its equilibrium, and constitutes in fact the resultant electric force experienced by the body. 6. Collected formula of relation between electric density on the surface of a conductor, electric diminution of air-pressure upon it, and resultant force in the air close to the surface. — Let, as before, p denote the first of these three elements, let p denote the second reckoned in units of force per unit of area, and let R denote the third. Then we have 7. Electric potential. — The amount of work required to move a unit of electricity against electric repulsion from any one position to any other position, is equal to the excess of the electric potential of the first position above the electric potential of the second position. Cor. 1 . The electric potential at all points close to the surface of an electrified metallic body has one value, since an electrified point, possessing so small a quantity of electricity as not sensibly to in- fluence the electrification of the metallic surface, would, if held near the surface in any locality, experience a force perpendicular to the surface in its neighbourhood. 335 Cor. 2. The electric potential throughout the interior of a hollow metallic body, electrified in any way by external influence, or, if in- sulated, electrified either by influence or by communication of elec- tricity to it, is constant, since there is no electric force in the interior in such circumstances. [It is easily shown by mathematical investigation, that the electric force experienced by an electric point containing an infinitely small quantity of electricity, when placed anywhere in the neighbourhood of a hollow electrified metallic shell, gradually diminishes to nothing if the electric point be moved gradually from the exterior through a small aperture in the shell into the interior. Hence the one value of the potential close to the surface outside, mentioned in Cor. 1, is equal to the constant value throughout the interior mentioned in Cor. 2.] 8. Interpretation of measurement by electrometer. — Every kind of electrometer consists of a cage or case containing a moveable and a fixed conductor, of which one at least is insulated and put in metallic communication, by what I shall call the principal electrode passing through an aperture in the case or cage, with the conductor whose electricity is to be tested. In every properly constructed electrometer, the electric force experienced by the moveable part in a given position cannot be electrically influenced except by changing the difference of potentials between the principal electrode and the uninsulated conductor or conducting system in the electrometer. Even the best of ordinary electrometers hitherto constructed do not fulfil this con- dition, as the inner surface of the glass of which the whole or part of the enclosing case is generally made, is liable to become electrified, and inevitably does become so when any very high electrification is designedly or accidentally introduced, even for a very short time ; the consequence of which is that the moving body will generally not return to its zero position when the principal electrode is perfectly disinsulated. Faraday long ago showed how to obviate this radical defect by coating the interior of the glass case with a fine network of tinfoil ; and it seems strange that even at the present day electro- meters for scientific research, as for instance for the investigation of atmospheric electricity, should be constructed with so bad and obvious a defect uncured by so simple and perfect a remedy. When it is desired to leave the interior of the electrometer as much light VOL. x. 2 B 836 as possible, and to allow it to be clearly seen from any external position with as little embarrassment as possible, a cage made like a bird's cage, with an extremely fine wire on a metal frame, inside the glass shade used to protect the instrument from currents of air, &c., may be substituted with advantage for the tinfoil network lining of the glass. It appears therefore that a properly constructed electro- meter is an instrument for measuring, by means of the motions of a moveable conductor, the difference of potentials of two conducting systems insulated from one another, of one of which the case or cage of the apparatus forms part. It may be remarked in passing, that it is sometimes convenient in special researches to insulate the case or cage of the apparatus, and allow it to acquire a potential differing from that of the earth, and that then, as always, the subject of measurement is the difference of potentials between the principal electrode and the case or cage, while in the ordinary use of the instrument the potential of the latter is the same as that of the earth. Hence we may regard the electrometer merely as an instru- ment for measuring differences of potential between two conducting systems mutually insulated ; and the object to he aimed at in per- fecting any kind of electrometer (more or less sensitive as it may be, according to the subjects of investigation for which it is to be used), is, that accurate evaluations in absolute measure, of differences of potential, may be immediately derivable from its indications. 9. Relation between electrostatic force and variation of electric potential. — § 7, otherwise stated, is equivalent to this : — The ave- rage component electrostatic force in the straight line of air between two points in the neighbourhood of an electrified body is equal to their difference of potentials divided by their distance. In other words, the rate of variation of electric potential per unit of length in any direction, is equal to the component of the electrostatic force in that direction. Since the average electrostatic force in the line joining two points at which the values of the potential are equal, is nothing, the direction of the resultant electrostatic force at any point must be perpendicular to the equipotential surface passing through that point ; or the lines of force (which are generally curves) cut the series of equipotential surfaces at right angles. The rate of varia- tion of potential per unit of length along a line of force is therefore equal to the electrostatic force at any point. 337 10. Stratum of air between two parallel or nearly parallel plane or curved metallic surfaces maintained at different potentials. — Let a denote the distance between the metallic surfaces on each side of the stratum of air at any part, and V the difference of potentials. It is easily shown that the resultant electrostatic force is sensibly constant through the whole distance, from the one surface to the other ; and being in a direction sensibly perpendicular to each, it must (§9) be equal to - . Hence (§ 4) the electric density on each of the a y opposed surfaces is equal to - — . This is Green's theory of the Ley den phial. 1 1 . Absolute Electrometer. — As a particular case of No. 1 0, let the discs be plane and parallel ; and let the distance between them be small in comparison with their diameters, or with the distance of any part of either from any conductor differing from it in potential. The electric density will be uniform over the whole of each of the opposed surfaces and equal to - , being positive on one and nega- tive on the other ; and in all other parts of the surface of each the electrification will be comparatively insensible. Hence the force of V2 attraction between them per unit of area (§§5 and 6) will be - — -, if A denote the area of either of the opposed surfaces ; the whole ya force of attraction between them is therefore A- — - . Hence, if the observed force be equal to the weight of w grains at Glasgow, we have and therefore Addition, dated April 12, 1860. Experiments on precisely the same plan as those of Table I. December 13, have been repeated by the same two experimenters, with different distances from *3 to '6 of an inch between the plates of the absolute electrometer, and results have been obtained con- firming the general character of those shown in the preceding Tables. 338 The absolute evaluations derived from these later series, must be more accurate than those deduced above from the single series of December 13, when the distance between the plates in the absolute electrometer was only *2 of an inch. I therefore by permission add the following Table of absolute determinations : — Length of spark in inches. Electrostatic forces according to estimated average of determina- tions of February 15, 23, 28, and fc 29, and March 2. X. •0034 5793 •005 5574 •006 5688 •0075 4862 •0111 4351 •0161 3287 •0222 3125 •023 3029 •0271 3055 •0356 2925 •0416 2865 •0522 2841 These results, as well as those shown in the preceding Tables, demonstrate a much less rapid variation with distance, of the electro- static force preceding a spark, at the greater than at the smaller distances. It seems most probable that at still greater distances the electrostatic force will be found to be sensibly constant, as it was certainly expected to be at all distances. The limiting value to which the results shown in the last Table seem to point must be something not much less than 2800. This corresponds to a pressure of 9600 grains weight per square foot. We may therefore conclude that the ordinary atmospheric pressure of 14,798,000 grains per square foot, is electrically relieved by the subtraction of 9600 on two very slightly convex metallic surfaces, at a distance of ^th of an inch or more, before the air between them is cracked and a spark passes. By taking into account the result of my preceding com- munication to the Royal Society, we may also conclude that a Danieirs battery of 5510 elements can produce a spark between two slightly convex metallic surfaces at ^th of an inch asunder in ordinary atmospheric air. 339 III. " On the Lines of the Solar Spectrum." By Sir DAVID BREWSTEK, K.H., D.C.L., F.R.S., and Dr. J. H. GLAD- STONE, F.R.S. Received January 26, 1860. (Abstract.) In a paper in the Transactions of the Royal Society of Edinburgh for 1833, Sir David Brewster stated that he had examined the lines of the solar spectrum, and those produced by the intervention of nitrous acid gas, and had delineated them on a scale four times greater, and in some parts twelve times greater than that employed in the beautiful map of Fraunhofer. None of these drawings, however, were published at the time ; they were increased by frequent observations continued through succeeding years ; and now having been collated, arranged, and added to by Dr. Gladstone, they form the diagrams accompanying this paper. The figures consist of — 1st. A map of the whole spectrum 58 inches long, and exhibiting about 1000 lines and bands. This map includes a great prolongation of the spectrum at the least refrangible end, before A, with a series of bands and lines not hitherto described. 2nd, 3rd, 4th, and 5th. Enlarged delineations of the portions of the spectrum between A and B, and between E and F, exhibiting additional lines, with still more magnified views of the groups a and b. 6th. A map of the two extremities of the solar spectrum as observed by Dr. Gladstone about noon-day at midsummer, consequently when the sun was at its greatest altitude. This shows several bands between A and B, and a series of lines in the lavender rays extending as far as M. Becquerel's N, and corresponding evidently with the maps published by him and by Professor Stokes, with the addition of finer lines. Yet this map represents the extreme spaces of the spectrum where there is no effect on the organ of vision, while that of M. Becquerel represents the want of chemical action, and that of Pro- fessor Stokes the absence of fluorescent power, 7th. A map of the "atmospheric lines" compiled from the independent observations of the two authors. These lines and bands are visible only when the sun is rising or setting, that is to say, when his beams traverse a long stratum of our atmosphere. In some cases 340 they are merely the deepening of bands seen at any time, in other cases they are bauds which appear for the first time when the sun is close to the horizon. Professor Piazzi Smyth has represented some of these lines in his delineations of the spectrum as observed from the Peak of Teneriffe, whence he had the advantage of seeing the sun at an altitude of — 1°*1. The most remarkable of the atmo- spheric lines are situated in the orange and yellow spaces, and one band just beyond D is discernible in the diffused light of a dull day at any hour, though it covers what is about the brightest part of the prismatic image obtained from direct sunshine. The western sky after sunset exhibits these phenomena in a striking manner, and with some variations that do not appear to depend altogether on the absence or presence of moisture, although when the sun looms red through a fog these lines also make their appearance. They are in no respect due to the mere reduction in the quantity of light. The dispersion and absorption of the more refrangible rays by the atmosphere, and by fogs, smoke, and such media as dilute milk and water, is a quite independent phenomenon. 8th and 9th. Enlarged views of A and B, when the light is acted upon by a long passage through the atmosphere. 10th. A map of the spectrum, exhibiting on a large scale the dark lines and bands which were seen by Sir David Brewster when nitrous acid gas is interposed between the prism and the source of light. Their position is identified by the insertion of the principal lines of the solar spectrum. They differ considerably from a smaller drawing of the same by Professor W. A. Miller, who employed a deeper stratum of the red gas. The light of the moon, which is only that of the sun reflected from her surface, exhibits all the principal lines from about B to H, and no fresh ones ; and when the luminary was near the horizon, the more prominent atmospheric lines were detected. The green colour was observed to extend a little beyond E- in the spectrum of moonlight, and the space between G and H appea'red lavender or lavender-grey instead of violet. In respect to the origin of these lines, it is conceivable that the light when emitted from the photosphere itself is deficient in these rays, or that they are due to absorption by the atmosphere of the sun, or by that of the earth. The first of these suppositions scarcely admits 341 of a positive proof. If the second be true, it might be expected that the light from the edge of the solar disk would exhibit more of these absorption bands than that from the centre, which must have traversed a smaller amount of atmosphere ; but such was not found to be the case. The third supposition is favoured by the fact that the atmo- sphere has unquestionably much to do with the manifestation of many of these lines, and by the analogy of the bands produced by nitrous acid gas, bromine vapour, and other absorbent media. The expert- mentum crucis of observing an artificial light through a long space of air was attempted by means of the revolving light on Beachy Head, as seen from Worthing at a distance of twenty-seven miles. It gave a negative result ; but on account of the great difficulty of detecting slight breaks in a faint thread of light, no great reliance is to be placed on the experiment. A similar doubt rests on the authors' observa- tions of fixed stars, and on the non-recognition by Fraunhofer of the ordinary lines in the light of Sirius and Castor, while on the other hand he did detect D and b in that of other stars. The origin of these lines is still an open question. The spectra of artificial flames sometimes exhibit bright lines coincident with the dark spaces of the solar spectrum. Thus the yellow band in the flames of soda, and several other substances, is identical in refrangibility with D ; but the most remarkable case is that of charcoal or sulphur burnt in nitre ; the spectrum shows three very prominent lines, two of which coincide with A and D, while a faint red line appears at B, and a group between it and A. A map is also given of the bright lines, principally orange, that make their appearance when nitrate of strontia is placed on the ignited wick of a spirit-lamp. IV. " On some New Volatile Alkaloids given off during Putre- faction." By F. GRACE CALVERT, Ph.D., F.R.S., &c. Re- ceived February 23, 1860. Some eighteen months ago my friend Mr. J. A Ransome, surgeon to the Royal Infirmary, Manchester, induced me to make some researches with the view of ascertaining the nature of the products given off from putrid wounds, and more especially in the hope of 342 throwing some light upon the contagion known as hospital gangrene. I fitted up some apparatus to condense the noxious products from such wounds ; but the quantity obtained was so small, that it was necessary for me to acquire a more general knowledge of the various substances produced during the putrefaction of animal matter, before I could determine the nature of the products from sloughing wounds. I therefore began a series of experiments, the general results of which I now wish to lay before the Society. Into each of a number of small barrels twenty Ibs. of meat and fish were introduced, and to prevent the clotting together of the mass, it was mixed layer by layer with pumice-stone. The top of each barrel was perforated in two places, one hole being for the purpose of admitting air, whilst through the other a tube was passed which reached to the bottom of the barrel. This tube was put in con- nexion with two bottles containing chloride of platinum, and these in their turn connected with an aspirator. By this arrangement air was made to circulate through the casks, so as to become charged with the products of putrefaction and to convey them to the platinum salt. A yellow amorphous precipitate soon appeared, which was collected, washed with water and alcohol, and dried. This precipitate was found to contain C, H, and N, but what is highly remarkable, sulphur and phosphorus enter into its composition. The presence of C, H, and N was ascertained by elementary analysis ; for the sulphur and phosphorus, a given weight of the platinum salt, 0*547 grni., was oxidized with nitric acid, and gave 0*458 grm. of sulphate of baryta = 11 per cent, of sulphur, and 0*266 of pyrophosphate of magnesia = 6 '01 per cent, of phosphorus. I also ascertained the presence of these two substances by heating a certain quantity of the platinum salt with strong caustic ley, when a liquid, volatile and inflammable alkaloid was obtained, whilst the sulphur* and phosphorus remained combined with the alkali and were easily detected. I satisfied myself during these researches, which have lasted more than twelve months, that no sulphuretted nor phosphuretted hydrogen was given oif ; and my researches, as far as they have proceeded, tend to prove that the * Some of the platinum salt was treated with C S2, which did not remove any free S, and the beautiful orange-yellow colour of the precipitate showed the absence of sulphuret of platinum. 343 noxious vapours given off during putrefaction, contain the N, S, and Ph of the animal substance, and that these elements are not liberated in the simple form of ammonia, and sulphuretted and phosphuretted hydrogen. I also remarked during this investigation, that, as putre- faction proceeds, different volatile bodies are given off. Before concluding, I may add, that when the platinum salts are heated in small test-tubes, they give off vapours, some acid and some alkaline, possessing a most obnoxious and sickening odour, very like the odours of putrefaction ; and that at the same time a white crystalline sublimate, which is not chloride of ammonium, is formed. As I foresee that these researches will occupy several years, I have deemed it my duty in the mean time to lay the above facts before the Society. March 1, 1860. Sir BENJAMIN C. BRODIE, Bart., President, in the Chair. In accordance with the Statutes, the Secretary read the following list of Candidates for election into the Society : — Frederick Augustus Abel, Esq. Somerville Scott Alison, M.D. Alexander Armstrong, M.D. Thomas Baring, Esq. Charles Spence Bate, Esq. John Frederic Bateman, Esq. Henry Foster Baxter, Esq. William Brinton, M.D. Edward Brown- Se'quard, Esq. Thomas William Burr, Esq. Richard Christopher Carrington, Esq. Alexander Ross Clarke, Capt. R.E. William White Cooper, Esq. Joseph Cubitt, Esq. Henry Duncan Preston Cunning- ham, Esq., R.N. Thomas Rowe Edmonds, Esq. James Fergusson, Esq. Francis Galton, Esq. Joseph Henry Gilbert, Ph.D. Robert Philips Greg, Esq. John Braxton Hicks, M.D. Sir William Jardine, Bart. Thomas Hewitt Key, M.A. Waller Augustus Lewis, Esq. Joseph Lister, Esq. Edward Joseph Lowe, Esq. David Macloughlin, M.I). 344 Rev. Robert Main, M.A. Gavin Milroy, M.D. Rev. Walter Mitchell. Ferdinand Mueller, M.D. Robert William Mylne, Esq. William Newmarch, Esq. Andrew Noble, Capt. R.A. Roundell Palmer, Esq., Q.C. Edmund Alexander Parkes, M.D. George Peacock, Esq. John Thomas Quekett, Esq. Rev. Thomas Robinson, D.D. Maxwell Simpson, Esq. Edward Smith, M.D. Sir James Emerson Tennent. Henry Ward, Capt. R.E. J. Forbes Watson, M.D. C. Greville Williams, Esq. Frederick Marow Eardley Wil- mot, Lieut. -Col. R.A. Matthew Digby Wyatt, Esq. The following communications were read : — 1. "On the Electrical Phenomena which accompany Muscular Contraction." By Professor C. MATTEUCCI. Commu- nicated by Dr. SHARPEY, Sec. R.S. Received January 7, 1860. Dr. Radcliffe has recently communicated to the Royal Society some observations on the nature of the electrical phenomena accom- panying muscular contraction. It is known that M. du Bois-Rey- mond admits that the muscular current diminishes during contrac- tion, and that he attributes the phenomena indicated by the galva- nometer to the momentary predominance of currents due to the polarization of the electrodes of platinum over the muscular current. In my last memoir on Electro-physiology, which was communicated to the Royal Society and appeared in the Philosophical Transactions for 1856, I proved that these phenomena take place independently of the existence of secondary currents of the electrodes, and I hence concluded, at least as regards the muscles of frogs, that during con- traction there is a current, or rather an instantaneous electrical discharge, which takes a contrary direction to that of the relaxed gastrocnemius, and in general to that of the current which is found on applying the extremities of the galvanometer to the extremities of the limbs of a frog. In order to avoid the influence of secondary polarity, M. du Bois- Reymond, and after him several other German physiologists, have 345 thought it expedient to contract and tetanize the gastrocnemius before closing the circuit of the galvanometer ; the deviation thus obtained is feebler than that which is due to the current of a muscle in repose, but never in a contrary direction to that due to this current. I have already remarked* that this result accords with that which is obtained by the ordinary experiment, in which the muscular current is in circulation previously to the contraction of the muscle. In fact, we know that by continuing to keep the muscle in contrac- tion, above all when the muscle remains tetanized, the electric phe- nomenon accompanying contraction (the effect of which is to pro- duce a deviation of the needle in a contrary direction to that of the current of a relaxed muscle) becomes gradually less intense as the contractions are more and more feeble, The method employed by Dr. Radcliffe is the same as that which I followed in my latest experiments ; that is, he made use of amalgam- ized plates of pure zinc as electrodes, immersed in a neutral solution of sulphate of zinc, and after having ascertained that there was no- thing to fear from the effects of secondary polarity, he says that he finds that the needle deviated by the muscular current descends, during contraction, towards zero, but only more slowly than it would have done had the circuit been opened. Dr. Radcliffe next examines another of my experiments, in which, instead of placing a gastrocnemius in the circuit, I employ a thigh cut transversely at the upper extremity, so that the needle remains deviated in a contrary direction to that of the gastrocnemius. In this arrangement of the experiment, when contraction is produced, the deviation of the needle increases, which is perfectly in accordance with the idea that during contraction a muscular current is developed in a contrary direction to the current of the relaxed gastrocnemius. Dr. Radcliffe attempts to explain this result by supposing (if I rightly understand his idea) that during contraction the contacts with the electrodes are deranged so as to facilitate the passage of the current of the relaxed muscle. Being unwilling to remain in doubt as to the nature of the elec- trical phenomena of muscular contraction, I have of late repeated and varied my experiments. * Nuovo Cimento, September 1858, p. 238. 346 As to Dr. Radcliffe's first remark, I shall only observe that in the principal experiment the needle does not merely move slowly towards zero during contraction, but is seen, during the first con- tractions, especially when the frog operated on is vivacious, to move rapidly down to zero, to oscillate, to pass to the opposite side, and sometimes even to remain fixed, while thus deviated, for a very short interval of time. This result, which is easily obtained and can be verified without difficulty, is the same, whether the electrodes are of platinum, like those employed by M. du Bois-Reymond, or of zinc. It is easy to understand that, in order to succeed in these experi- ments, it is desirable that the needle should be as little deviated as possible before the contractions : this object is best ensured in the following way : — I prepare the frog by reducing it to two thighs, leaving a single lumbar nerve in order to obtain contractions in one of the thighs. Instead of saturated solution of sulphate of zinc, I employed a weak solution of this salt, in order to avoid any alteration of the surface of the muscles ; and finally, in order to maintain exactly the same points of contact between the two electrodes and the two near points of the middle portion of the thigh, I employ two fine woollen cords or two thin strips of card-board fixed with sealing-wax on a plate of glass and soaked in the same solution. The experi- ment is made by applying the glass plate with a certain pressure on the thigh, so that the two cords on one side touch the thigh, and on the other are placed in contact with the cushions of flannel or card-board which are immersed together with the electrodes, accord- ing to the method followed by M. du Bois-Reymond. I think it useful to describe in a few words a little apparatus which affords a good deal of facility for making these experiments. It consists in a small square block of wood, with a cavity deep enough to receive the electrodes and the cushions. It is hardly necessary to say that this cavity is coated with a varnish of sealing- wax and divided in the middle by a glass plate. Another cavity in the same block serves as a recipient for the two thighs ; the sciatic nerve extends beyond the block, and rests on two platinum wires which communicate with the pile or with the electro-magnetic ma- chine. The communication between the thigh and the electrodes is established by means of the glas^ plate in the manner above de- 347 scribed, that is, I press this strip of glass slightly on the middle of the thigh on one side, and at the same time the extremities of the two woollen cords come to rest on the cushions. The movements of the needle are observed through a telescope (lunette). I have re- peated this experiment thirty or forty times. Sometimes, and this case is the most frequent, the first deviation produced by the muscle in repose is directed in the same sense as that of the current of the gastrocnemius ; sometimes the current is null, or almost null ; some- times, and this case is the most rare, the deviation is in a contrary direction, and this occurs most frequently in operating on the hinder portion of the thigh. In all these experiments, the moment that the thigh begins to contract, the needle moves in a constant direction; the deviation which intervenes is greater or less according to the force of the contraction, and indicates constantly a descending discharge or current of extremely short duration, which traverses the thigh in the direction of the ramification of the nerves, and in a contra^ direction to the current of the gastrocnemius. II. "An Inquiry into the Muscular Movements resulting from the action of a Galvanic Current upon Nerve." By CHARLES BLAND RADCLIFFE, M.D., F.R.C.P., Physician to the Westminster Hospital. Communicated by Dr. SHARPEY, Sec. R.S. Received February 2, 1860. (Abstract.) In a lecture delivered about two years ago*, in which he treats among other things of the muscular movements resulting from the action of a galvanic current upon a motor or mixed nerve, Pro- fessor Claude Bernard says that some of the more important of these movements have been overlooked, and he quotes an account of some investigations by Dr. Rousseau of Vezy, which do away with certain very perplexing variations in the order of these movements. The movements resulting from the action of a galvanic current upon nerve are usually divided into the three periods of double, alternate, and single contraction which are set down in the following Table : — * Lemons sur la Physiologic et Pathologic du systeme nerveux. Tome i. Le (#, y)=0, then the possible positions of P are limited to those in which for any scalar value of x there exists a corresponding scalar value of y. The ensemble of all such positions of P constitutes the 'locus' of the two equations, viz. the 'concrete equation' OP=# . Ol+y . OJ, and the 'abstract equation' y=f> x. The peculiarity of the present theory consists in the recognition of these two equations to a curve, of which the ordinary theory only furnishes the latter, and inefficiently replaces the former by some convention respecting the use of the letters, whereby the coordinates themselves are not made a part of the calculation. A variation in either of these two equations will occasion a dif- ference either in the form or position of their locus. If the abstract equation be y=ax-\-b, where a and b are any scalars, the concrete equation OP=^p . Ol+y .OJ becomes OP=# . (Ol + a . OJ) + b . OJ, which shows that OP is the appense of a constant line, and a line in a constant direction, and hence its extremity P must lie on a line in that direction drawn through the extremity of the constant line. Also, since the length of OP is VO'+y2) times the length of OI, the locus of the two equations OP=# . Ol-f y . OJ and 417 must be a circle. From these equations all the usual theory of the straight line and circle may be readily deduced, and all ambiguity respecting the representation of direction by the signs (-}-) and (— ) may be removed. Thus if the loci of OP=# . Ol+y . OJ, y=ax+b, and OF=^ intersect in the point Q, and OQX be the unit radius on the J side of OI (produced both ways), determined by the equation then V(l+«2)-OQ will =bOQl. And a line drawn from the locus of P parallel to OQ to pass through the point X, where OX=;T1 .OI+ yr OJ, will be represented in magnitude and direc- tion by y^-a^-b vo+o* From this result the usual theory of anharmonic ratios is immediately deducible without any fresh * convention ' respecting the signs ( + ) and (— ). As every locus has two equations, each equation requires separate consideration. The investigations concerning the abstract equation remain nearly the same as in the usual theory. When the abstract equation is given indirectly by the elimination of two constants between three equations, the result corresponds to the locus of the intersection of two curves varying according to a known law, ' coordinates proper,' leading in its simplest forms, first, to Descartes' original conception of curves generated by the intersection of straight lines moving according to a given law parallel to two given straight lines, and secondly, to Pliicker's 'point coordinates.' The true relation of Pliicker's 'line coordinates' to the ordinary system is immediately apparent on comparing the two sets of equations : (1) Concrete OP=#. Ol-j-y . OJ Abstract F(a?,y) = 0, ( 2 ) First abstract y~ax+b Second abstract F(a, &)=0. The second set of equations determines a curve by supposing a and b to vary, then eliminating a and b} and referring the ultimate abstract .2 G2 418 equation to the concrete equation (1). On comparing these two sets of equations, we see that x and y in the first are involved in precisely the same manner as a and b in the second, so that if any equation F(w, v) = Q were given, it might determine one or the other by pre- cisely the same algebra, according as x, y or a, b were substituted for u, v. Whence flow Pliicker's theories of collineation and reciprocity. The investigations respecting the concrete equation, on the other hand, are altogether new. The most general form of the two equations, is Concrete, OR=/;O, y) . OA+/2(>, y) . OB Abstract, 0(X y)=0, which will clearly determine a curve as definitely as before. If in lieu of the abstract equation 0 (#, y)=0, we were given the locus of the two equations OM=a? . OA+3/ . OB, 0(#, y)=0, and from any point M in this curve we drew MN parallel to OB, cutting OA produced in N, so that ON=#.OA, NM=y .OB, we could find x and y from this curve, and consequently form OL=/;(#, y) . OA, and LR=/2<>, y) . OB, and by this means determine the point R, where OR=OL + LR, in the locus of the general equations, corresponding to the point M in the particular locus. The general form is therefore the algebraical expression of a curve formed from another curve by means of ope- rations performed on the coordinates of the points in the latter, as when an ellipse is formed from a circle by altering the ordinates in a constant ratio. The algebraical treatment of this case consists in putting and between these equations and 0 (#, y) = 0, eliminating x and y, to find \l/ (p, y) must be all scalar. Thus, in the case of the parabola derived from a circle, by substituting for the ordinate of a point in the latter its distance from a known point in the circumference of the same, we know that it is impossible to derive more of the para- bola than can be obtained by taking the diameter of the circle as the ordinate. The algebraical process gives first (1) OR=o7 . OI+ V 0*2+2/2) • OJ, y2+#2=2a# ; and then, putting p= xt J(2ax). But x, and therefore p, always lies between the limits 0 and 2«, and hence q must lie between the same limits. Consequently the only part of the curve (2) represented by the equations (1) is the semi-parabola contained between the origin and the ordinate 2« . OJ. This general form of the concrete equation, therefore, furnishes an elementary method of representing curves or parts of curves. Thus OR=(A + a cos CL + X cos a) . OI + (^:( + a sin a + x sin ri)).OJ are the equations of a line HK=2« (cos a . Ol + sin a . OJ), and having one of its extremities determined by the equation OH=A.OI-M.OJ, so that its length is 2« times that of OI and the angle (OI, HK)=a. To determine the intersections of two such finite curves, given by the equations OP-rtfo y) . OI +/,(*, y) . O J, 0<>, y) = 0, and OF=//(ar',y').OI+/8'(^y').OJ, 0'2/)=0, and corresponds to what has been hitherto insufficiently designated as the * locus of the equation' 0(#, y) = 0. It presents a necessarily imperfect image of that equation. Clinant Plane Geometry. — Reverting to the original pair of equations OP=# . Ol+y . OJ, $,(#, y)=0, and remembering that even if clinant ('impossible* or 'imaginary') values were substituted for so and y in the expressions x . OI, y . O J, they would still represent definite lines (see abstract of Paper on * Laws of Operation, &c.,' Proceedings, vol. x. p. 85), and con- sequently the line OP would still be perfectly determined, we see that the limitation of as and y to scalar values in the previous inves- tigations was merely a matter of convenience. We may therefore give x any clinant value, and after determining the correspondent clinant value of y from fy(oe, y)=0 (which will always exist if the equation is algebraical), substitute these values in the concrete equation, and thus find OP, and consequently the locus of the equations. We may observe, however, that as a clinant involves two scalars, we must have some relation given between them, directly or indirectly, in order that there may be only one real variable, without which limitation the locus would in every case embrace the whole plane. The general algebraical process is as follows, the Roman letter i being used for + V(-l). Let OP=P(X1, X2...Xn) . OI, where /ij ...Xn=pw + i . qn, and all the p, q are scalar. We can 421 reduce this expression to OP=(P1+i • P2) • 01, where Pl and P2 are scalar 'formations' (or ' functions') of the 2n scalars^9r . pn, ql. .qn. As this is equivalent to OP=P1 . OI + P2 'OJ> it is precisely the same as the general scalar concrete equation lately investigated. But one abstract equation will now no longer suffice ; for if we put P1=o?, P2=y, we must have 2n — 1 additional equations, in order ultimately to find f(xy y) = Q by eliminating 2n variables between 2»+ 1 equations. The result, OP=# . OI +y . OJ, f(x, y)=0, with the conditions of scalarity, will then enable us to determine the locus by the usual process. If there be only two clinants, X==p-f i . q, and Y = r+i . s, and we have given OP=P . (X, Y) . OI ; C . (X, Y)=0, where C=0 may be termed the ' curve equation/ these reduce to OP = P1.OI + P2.OJ, C^O, C2=0, where Px, P2, C^ C2 are formations of p, q, r, s, so that, on putting Pj=o7, P2=y, we have only four equations, between which we cannot eliminate p, q, r, s. This again shows the necessity of some ad- ditional relation, A.(p, q, r, s) =0, which may be called the ' assignant equation,' in order finally to discover /(#, y) = 0, and thus determine the locus. The only case ordinarily considered is where X is scalar. This corresponds to putting q=Q for the assignant equation. Hence q disappears and we have OP=P1.OI + P2.OJ, CT = 0, C2 = 0, where PT, P2, C^ C2 are formations of p, r, s, and hence, putting P1==#, P2=y, we immediately eliminate p, r, st and determine the locus. This general theory is illustrated by numerous examples, and in particular Pluck er's * involutions ' by means of ' imaginary lines' are fully explained by help of the really existent lines of this theory. The general theory of the intersection of two *clinant loci' is precisely analogous to that of two scalar loci with general concrete equations. In the particular case where the concrete equations are the same for both, or the reduced equations are OP^CP^, q, r, «) + i . P2<>, q, r, «)] . OI, . Vi(P> Q> r> *) = 0, C2(p, q, r, *) = 0, A(p, q, r, s) = 0, and OP'KW* «'. ^ «')+i - W> ?', r't *')] .OI, C/V, ?', r', *') = 0, C2V> q'} r', ^) = 0, A'(p', ?', r', *') = 0, 422 the intersection will evidently be determined by putting p—p', q = q', r=.r\ s=sf, which will give six simultaneous equations between four variables, p, q, r, s or^/, q', r', s1. This gives two equations of condition. If, however, no assignant equations were given, we might determine the values of p, q, r, s from the four reduced curve equa- tions, and then assume any assignant equations compatible with these solutions. This is more readily done by determining X and Y from the two unreduced curve equations C(X, Y)=0, C'(X, Y)=0. The process then corresponds to that for the simplest scalar case of intersection. If the values of X and Y prove to be scalar, then the assignant equations are # = 0 and $=0, and we have an ordinary scalar case of intersection. But if this is not the case, and we find we may take (0-*i)» .(?-6»)=0, (s-^)... 0-O = 0, among others, as assignant equations and determine the corre- sponding loci. These loci will be found to intersect in all the (per- fectly real) points determined by the values of X and Y, but not necessarily in these only. Such points will of course not belong to the curves derived from putting # = 0, s=0, and hence cannot in any sense be called points of intersection of these curves, although they have hitherto been termed ' imaginary points of intersection.' The discovery of equations to loci described according to some geometrical law, furnishes a convenient illustration of this clinant theory. From any point O, draw radii vectores OU, OR to any curves, and make RP=A . OU, where h is scalar. Put OP=O+ i . j) . OI, OR=(r+i . *) . OI, OU=(w+i . v) . OI. Then the condition OP=OR + RP gives p=r+ hu, q=s+hv, which correspond to the two reduced curve equations. We now require three more equations in order to eliminate four of the six scalars P> q> r> s» Uy v> and find a relation between the two remaining scalars, sufficient with one of the above concrete equations to determine the locus of one of the points P, R, U. Two of these three equations will amount to assigning the locus of two of these points, and the third equation will amount to assigning some relation between the angular motions of OU and OR, without which the loci can clearly 423 not be determined. This third condition is frequently given in the form of requiring M (a point in RP, produced either way if necessary where RM = £ . OU and k is scalar) to lie on a given curve. It is then most convenient to introduce two new scalars m and ny so that OM=O+i . n) . OI, when the condition OM=OR+RM, gives the two additional equations m=r-\-kut n=s+kv, which with the five others will serve to eliminate six of the eight scalars, m, n, p, qy r, s, u, v, and leave the required abstract equation between the remaining two. The eliminations are very simple in a great variety of curves. This theory is fully illustrated by examples. . The first problem in the transformation of coordinates, ' given an alteration in the concrete and curve equations, to find the corre- sponding alteration in the assignant equation, so that the curves may remain identical, extent excepted/ is solved thus. Given OP=(P1+i.P2).OI, €, = 0, C2=0, A = 0, for the original curve, and OP' = (P/+i . P2') . OI, C/=0, C2'=0 for the new equations, where the unaccented letters are formations ofp, qt r, 5, and the accented of p1, qf, /•', s'. Since OP=OP', we have ?! = ?/, P2 = P2', between which and C1=0, C2=0, A=0 eliminate p, q, rt s and use the final equation, which will only involve p', c£, r', s' as the assignant equation A'=0, which is independent of any particular form of the curve equations C/ = 0, C2f=0. The ordinary case of the transformation of coordinates is a particular case of this. The second problem, ' given an alteration in the concrete and assignant equations, to find that in the curve equations,' requires the assignant equation to be put in the form 04-^/=0, which is possible in an infinite number of ways. Then if the locus be that of OP=# . 01+ y . OJ, 0(tf, y) + ftar, y) = 0, and we have given OP= [Pa(p, q,r,*) + i. Pa(p, q, r, s}} . OI, '(p, q, r, *) + \l/(p, q, r, s) = 0=A, we put 0=0', 4>=^'» and hence finding x=t(p, q, r, s), y = rj(p, q, r, *), we use P!=$, P2=*7 as the two curve equations. The third pro- 424 blem, 'given an alteration in the curve and assignant equations, to find that in the concrete equation,' admits of a similar solution. Given as the equations to the locus, and also C^p, q, r, *) = 0, Ca(p, q, r, *) = 0, A = f '(p, q, r, s) + V(p, q, r, « = )0 as the new curve and assignant equations: put 0 = 0', ^=^', and determine x = £(p, q, r, *), y=r)(p, q, r, s), and then use as the new concrete equation. The result is independent of the form of the curve equations. The geometrical significance of these transformations is that there are no ' families ' of plane curves. ' Clinant radical loci,' or curves which furnish a sensible geome- trical picture of the relations of the corresponding clinants which satisfy any abstract equation, may be obtained thus. Let the given equation be C (X, Y)=0. This may be regarded as two reduced curve equations, Ci (P> Q> ry *) = 0, C2 (p, q,r,s) = 0. The values of X are assumed by drawing radii vctorees to points in any curve, and the corresponding values of Y have to be pictured. We must therefore have some equation A=0, which in combination with the other two will give the curve by which X is thus determined. Eliminating the scalars, p, q, r, s, two and two, between these three equations, we obtain the following six, of which the first and last, and one of the intermediate ones, are in general only required : We now construct the curves containing the points X, S, Y, as the loci of the equations OX=OP+PX = OS=OP+PS = OY = OR+RY = OR+PS = (r+ i . *) . OI,/6 (r, *)=0. Set off OP at pleasure on OI (produced both ways), and draw the ordinate PXS, cutting the two first curves in X and S. Through S draw SY parallel to OI, cutting the third locus in Y : then if OX=X . OI, and OY=Y . OI, X and Y are corresponding solutions 425 of C(X, Y)=0. When only scalar solutions are required, the abstract equations to the first and last curve become q—Q, $=0, so that both of these curves coincide with OI produced both ways, and the intermediate or connecting curve is the ordinary scalar radical locus. Scalar Solid Geometry. — The same theories apply with proper modifications. The concrete equation with one abstract equation, /(#, y, £)=0, gives a surface for its locus, and with two abstract equations, /1(^y,^)=0, /a(a?,y,*) = 0, a curve. From these equations all the ordinary theories are most readily deduced. We may also take the concrete equation more generally in the form OP=/; O, y, *) . OI+/2 (*, y, z) . OJ+/3 (x, y, z) . OK, the abstract equation being F(a?, y,*r)=0. We obtain the surface by putting xl =fv yl =/2, z^ =/3, and eliminating x, y, z between these equations and F=0, thus finding ^ (a?y y,, ^) = 0. The locus of OP=^ . OI+yi . OJ+*! • OK, 0 (x19 yv ^)=0 must be limited by the condition that not only x, y, z, but also / (*, y, z), /2 (ar, y, z\ /8 (a?, y, z) must all be scalar. If three variable parameters a, 6, c are introduced, we require in addition three equations of condition, F1=0, F2=0, F3=0, between x, y, zt a, bt c, in order to eliminate all six and find $ (xl3 ylt 2'1) = 0. Clinant Solid Geometry. — Some precaution is now necessary to indicate the plane on which the quadrantal rotation symbolized by i is to take place. This is effected by introducing all three coordinate axes into the concrete equations. Let the abstract equation be F(X,Y,Z) = 0. Then, supposing this equation reduces to F^O, F2=0, where Fx and F2 are forma- tions of the six scalars jp, and we find 0?=^ . 01+ P2 . OJ+P3 . OK. Putting #=P1} y=P2, £=P3J and eliminating the six scalars between these three equations and At=0, A2=0, Fa = 0, F2=0, the locus becomes that of OP=# . OI+y • OJ+* . OK, 0 (a?, y, ^)=0, which is limited by the conditions of scalarity. After illustrating this theory by an example, the theory of inter- section, when the elimination gives clinant values to determine the points, is discussed. The general theory is further illustrated by the determination of equations to loci, leading to very simple and ex- tremely general modes of finding families of surfaces. The problems of the transformation of coordinates and of radical loci are shown to be precisely analogous to those of plane curves. It will be evident that these investigations merely open out a new field for algebraical geometry, of which it is impossible to foresee the extent. 427 March 29, 1860. Sir BENJAMIN C. BRODIE, Bart., President, in the Chair. The Right Hon. Lord Belper and Dr. W. Bird Herapath were admitted into the Society. The following communications were read : — I. " On the Volumetric Relations of Ozone and the Action of the Electrical Discharge on Oxygen and other Gases." By THOMAS ANDREWS, M.D., F.R.S., and P. G. TAIT, Esq., M.A. Received February 20, 1860. (Abstract.) This paper contains the full details of the authors' experiments on the volumetric changes which occur in the formation of ozone. From three distinct series of experiments, performed by different methods, they show that when ozone is formed from pure oxygen by the action of the electrical discharge, a condensation takes place, as had already been announced in a former Note published in the * Proceedings.' But the condensation is much greater than the earlier experiments of the authors on the expansion by heat of electrolytic ozone had indicated. It is, in fact, so great, that if the allotropic view of the constitution of ozone be correct, the density of that body, as compared with oxygen, would be represented by a number cor- responding to the density of a solid or liquid rather than that of a gaseous substance. This conclusion follows necessarily from the authors' experiments, unless it be assumed that when ozone comes into contact with such substances as iodine, or a solution of iodide of potassium, one portion of it is changed back into common oxygen, while the remainder enters into combination, and that these portions are so related to one another, that the expansion due to the one is exactly equal to the contraction arising from the other. For the details of the experiments and of the methods of investigation em- ployed, reference must be made to the original paper. The second part of the communication is devoted to the action of the silent discharge and of the electrical spark on other gases. 428 Hydrogen and nitrogen undergo no change of volume when exposed to the action of either form of discharge. Cyanogen is readily de- composed by the spark, but presents so great a resistance to the passage of electricity, that the action of the silent discharge can scarcely be observed. Protoxide of nitrogen is readily attacked by both forms of discharge, with increase of volume and formation of nitrogen and hyponitric acid. Deutoxide of nitrogen exhibits the remarkable example of a gas which, under the action either of the silent discharge or of the spark, undergoes, like oxygen, a diminu- tion of volume. It also is resolved into nitrogen and hyponitric acid. Carbonic oxide has given results of great interest; but the nature of the reaction has been only partially investigated. The silent discharge decomposes this gas with production of a substance of a bronze colour on the positive wire. The spark acts differently, destroying, as in the case of oxygen, the greater part of the con- traction produced by the silent discharge. The authors are engaged in the further prosecution of this inquiry. II. " On the Equation of Differences for an Equation of any Order, and in particular for the Equations of the Orders Two, Three, Four, and Five." By ARTHUR CAYLEY, Esq., F.R.S. Received March 2, 1860. (Abstract.) The term equation of differences, denotes the equation for the squared differences of the roots of a given equation ; the equation of differences afforded a means of determining the number of real roots, and also limits for the real roots of a given numerical equation, and was upon this account long ago sought for by geometers. In the Philosophical Transactions for 1 763, Waring gives, but without de- monstration or indication of the mode of obtaining it, the equation of differences for an equation of the fifth order wanting the second term : the result was probably obtained by the method of symme- tric functions. This method is employed in the ' Meditationes Alge- braicee* (1782), where the equation of differences is given for the equations of the third and fourth orders wanting the second terms ; and in p. 85 the before-mentioned result for the equation of the fifth order wanting the second term, is reproduced. The formulae for 429 obtaining by this method the equation of differences, are fully deve- loped by Lagrange in the ' Traite des Equations Numeriques ' (1808) ; and he finds by means of them the equation of differences for the equations of the orders two and three, and for the equation of the fourth order wanting the second term ; and in Note III. he gives, after Waring, the result for the equation of the fifth order wanting the second term. It occurred to me that the equation of differences could be most easily calculated by the following method. The co- efficients of the equation of differences, quti functions of the differences of the roots of the given equation, are leading coefficients of covari- ants, or (to use a shorter expression) they are "Seminvariants"*, that is, each of them is a function of the coefficients which is reduced to zero by one of the two operators which reduce a covariant to zero. In virtue of this property they can be calculated, when their values are known, for the particular case in which one of the coefficients of the given equation is zero. To fix the ideas, let the given equation be (*^£0, l)w=0 ; then, when the last coefficient or constant term vanishes, the equation breaks up into v=0 and into an equation of the degree (n — 1), which I call the reduced equation; the equation of differences will break up into two equations, one of which is the equation of differences for the reduced equation, the other is the equation for the squares of the roots of the same reduced equation. This hardly requires a proof ; let the roots of the given equation be a, /3, y, S, &c., those of the equation of differences are (a — 13)2, (a-y)2, («-S)2, &c., (/3-y)2, (/3-S)2, (y-3)2, &c. ; but inputting the constant term equal to zero, we in effect put one of the roots, say a, equal to zero ; the roots of the equation of differences thus become /32, y2, S2, &c., (/3-y)2, (/3-£)2, (y-£)2, &c. The equation for the squares of the roots can be found without the slightest diffi- culty ; hence if the equation of differences for the reduced equation of the order (n— I) is known, we can, by combining it with the equation for the squares of the roots, form the equation of differences for the given equation with the constant term put equal to zero, and thence by the above-mentioned property of the Seminvariancy of the co- efficients, find the equation of differences for the given equation. The present memoir shows the application of the process to equations of the orders two, three, four, and five : part of the calculation for the * The term " Seminvariant " seems to me preferable to M. Brioschi'sterm Pen- invariant. 430 equation of the fifth order was kindly performed for me by the Rev. R. Harley. It is to be noticed that the best course is to apply the method in the first instance to the forms (a, b, . .^jffl, 1)%=0, without numerical coefficients (or, as they may be termed, the denumerate forms), and to pass from the results so obtained to those which belong to the forms (a, 6, . .^v, l)n=0, or standard forms. The equation of differences, for (a— /3)2, &c., the coefficients of which are semin variants, naturally leads to the consideration of a more general equation for (a— /3)2 (x — -yy)2 (#— £y)2, &c., the coefficients of which are covariants ; and in fact, when, as for equations of the orders two, three, and four, all the covariants are known, such co- variant equation can be at once formed from the equation of dif- ferences ; for equations of the fifth order, however, where the cova- riants are not calculated beyond a certain degree, only a few of the coefficients of the covariant equation are given. At the conclusion of the memoir, I show how the equation of differences for an equation of the order n can be obtained by the elimination of a single quan- tity from two equations each of the order n — 1; and by applying to these two equations the simplification which I have made in Bezout's abridged method of elimination, I exhibit the equation of differences for the given equation of the order n, in a compendious form by means of a determinant ; the method just employed is, however, that which is best adapted for the actual development of the equation of differences for the equation of a given order. III. " On the Theory of Elliptic Motion." By ARTHUR CAYLEY, Esq., F.R.S. Received March 9, 1860. The present Note is intended to give an account of the results which, by means of a grant from the Donation Fund of the Royal Society, I have procured to be calculated for me by Messrs. Greedy and Davis, and which are contained in a memoir presented to the Royal Astro- nomical Society, entitled " Tables of the Developments of Functions in the Theory of Elliptic Motion." The notation employed is ry the radius vector ; /, the true anomaly ; a, the mean distance ; e, the excentricity ; ff, the mean anomaly ; 431 so that Z and f,=elta(e,g) (read elliptic quotient radius and elliptic true anomaly), are known functions of e, g. Moreover x denotes the periodic part of -, and y a the equation of the centre or periodic part of/; so that and xy y are also known functions of e, g. Formulae for the development in multiple cosines or sines up to the terms in e* of <*•••' • • • O where j is an indeterminate symbol, are given by Leverrier in the ' Annales de 1'Observatoire de Paris,' t. i. (1855), pp. 346-348 ; and what has been done is the deduction from these of the developments in the like form of various functions of the forms where,; has given integer values. It is to be remarked that a cosine series is in general represented in the form 2 [cos]1 cos ig, where * extends from — oo to + oo , and the coefficients [cos]1 satisfy the con- dition [cos] ~l= — [cos]1, and that a sine series is represented in the form S [sin]* sin ^r, where * extends from — ooto + oo , and the coefficients [sin]1 satisfy the condition [sin] ~l= — [sin]1' (this implies [sin]°=0). In the case of a pair of corresponding functions, xm cosjf (r\±m /r\±m -) cosjf/and I - J shy/, one of them expanded in the form S [cos]1 cos igt and the other in the form 2 [sin]1 sin ig, the sums and differences of the corresponding coefficients [cos]', [sin]1 (represented by the notation [cos + sin]*, and which are ob- viously such that [cos + sin] ~l = [cos — sin] *, [cos + sin] ° = [cos] °) are for many purposes equally useful with the coefficients [cos]*, [sin]1'* and they are in the memoir tabulated accordingly ; and the several functions tabulated are as follows : viz. VOL. x, 2 IJ 432 rx+^ ««J i ^» 'y*~ (U, , A ... /rO 1 «2 V* > * J * • — 1 =D COS sin , [cos] = 1 to;' =7, [cos], [sin], [cos±siri] all the developments being carried up to e7, the limit of the for- mulae from which they are deduced. IV. " On the Application of Electrical Discharges from the In- duction Coil to the purposes of Illumination." By J. P. GASSIOT, Esq., F.R.S. Received March 29, 1860. The subjoined figure represents a carbonic acid vacuum-tube of about ^ of an inch inter nal diameter, wound in the form of a flattened spiral. The wider ends of the tube, in which the platinum wires are sealed, are 2 inches in length and about ^ an inch in diameter, and are shown by the dotted lines ; they are enclosed in a wooden case (indicated by the surrounding entire line), so as to permit only the spiral to be exposed. When the discharge from a RuhmkorfFs in- duction apparatus is passed through the vacuum- tube, the spiral becomes intensely luminous, ex- hibiting a brilliant white light. Mr. Gassiot, who exhibited the experiment at the meeting of the Society, caused the discharge from the induction coil to pass through two miles of cop- per wire ; with the same coil excited so as to give a spark through air of one inch in length, he ascertained that the luminosity in the spiral was not reduced when the discharge passed through 14 miles of No. 32 copper wire. 433 April 19, 1860. Sir BENJAMIN C. BRODIE, Bart., President, in the Chair. Professor Auguste De la Rive, of Geneva, and Sir John Bowring, were admitted into the Society. The CROONIAN LECTURE was then delivered by JAMES PETTI- GREW, Esq., " On the Arrangement of the Muscular Fibres of the Ventricular portion of the Heart of the Mammal." (Abstract.) The Lecturer began by referring to the descriptions of the arrange- ment of the ventricular fibres of the heart given by previous in- quirers, more especially Lower, Senac, Wolff, Gerdy, Duncan, and Reid ; he then proceeded to give an account of the results of his own investigations, which had been conducted on the hearts of the Sheep, Calf, Deer, Ox, Horse, &c. ; all of which, he observed, bear a perfect resemblance to the human heart* . In order, as much as pos- sible, to overcome the difficulties of the subject, he availed himself of drawings, explanatory diagrams, and models illustrating the course and relation of the fibres. To these last, however, he observed he attached no special importance, further than that they were useful vehicles of communication ; and it was to the dissections themselves, some of which were before the Society, that he looked for a corro- boration of the statements he advanced. Commencing with the left ventricle, which he believes to be the typical one, the Lecturer stated that, by exercising a little care, he had been enabled to unwind as it were its muscular substance, and so to separate its walls into several layers f, each of which is charac- terized by a difference in direction. Seven layers, at least, can be readily shown by dissection ; but he believes they are in reality nine ; viz. four external, the fifth or central, and four internal. He explained how the external fibres are continuous with the internal fibres at the apex, as was known to Lower J, Gerdy §, and others, * Mr. Pettigrew's researches include also the arrangement of the fibres in the ventricles of the Bird, Reptile, and Fish. f Senac (Traite de la Structure du Coeur, &c. [Paris, 1749] , planche 8) figures four layers ; and Searle (Cyc. of Anat. and Phys., art. " Heart") speaks of three. t Tractatus de Corde, &c. London, 1669. § Recherches, Discussions et Propositions d'Anatomie, Physiologie, &c. Paris, 1823. 2 H2 434 and how the fihres constituting the several external layers are con- tinuous with corresponding internal layers likewise at the base*, — a fact to which the Lecturer drew particular attention, as being con- trary to the generally received opinion, which is to the effect that the fibres at the base are non-continuous, and arise from the auriculo- ventricular tendinous rings — which, as he showed by numerous dis- sections, is not the case. Coming next to the question of the direction of the fibres, he showed how there is a gradational sequence in the direction of the fibres constituting the several layers. Thus the fibres of the first layer are more vertical in direction than those of the second, the second than those of the third, the third than those of the fourth, and the fourth than those of the fifth, the fibres constituting which layer are transverse, and run at nearly right angles to those of the first layer. Passing the fifth layer, which occupies the centre of the ventricular wall and forms the boundary between the external and internal layers, the order of things is reversed ; and the remain- ing layers, viz. six, seven, eight, and nine, gradually return to the vertical in an opposite direction, and in an inverse order. This re- markable change in the direction of the external and internal fibres, which had in part been figured by Senac, and imperfectly described by Reid f, as well as other detached and important facts ascertained by himself and others — such as the continuity of the fibres at the apex and base, already adverted to — he suggested might be accounted for by the law of the double conical spiral, which he proceeded forthwith to explain. The expression of the law, as he conceives it, with reference to the arrangement of the fibres in the ventricle, is briefly the follow- ing. By a simple process of involution and evolution, the external fibres become internal at the apex, and external again at the base ; so that whether the fibres be traced from without inwards, or from * The late Dr. Duncan, Jun., of Edinburgh, was aware of the fibres forming loops at the hase, but seems to have had no knowledge of the continuity being occasioned by the union of corresponding external and internal layers, or that these basal loops were prolongations of like loops formed by similar correspond- ing external and internal layers at the apex — a point which the Lecturer believes he is the first to establish. t Cyc. of Anat. and Phys., art. " Heart." London, 1839. 435 within outwards, they always return to points not wide apart from those from whence they started. In order to illustrate the principle of the double conical spiral in the above sense, he took a sheet of net, through which parallel threads of coloured wool, representing the individual fibres, were drawn at intervals ; and laying it out on the table before him, with the threads placed horizontally, seized it by the right-hand off corner, and rolled it in upon itself (i. e. towards his own body) seven turns, so as to produce a cone whose walls con- sisted of nine layers*. On gradually unwinding the walls of the cone thus fashioned (which is tantamount to undoing the spirals), so as to imitate the removal of consecutive layers from the walls of the ventricle, he finds that the gradation in the direction of the several layers just specified is distinctly marked ; and that these layers, as was exhibited in various dissections, find a counterpart in the ventricle itself. Thus (the heart being supposed to be placed upright on its apex) in the first external layer the threads are seen running from base to apex, and from left to right f, almost vertically; in the second layer they are slightly oblique ; this obliquity increases in the third, and still more in the succeeding layer, till in the fifth or central one the direction of the threads becomes transverse. After passing the central layer, the direction of the threads (as of the fibres) is reversed ; in the sixth layer they begin to turn from right to left, with a slight inclination upwards ; and in succeeding layers gradually become more and more vertical, until the innermost, or ninth, is reached, in which they -become as vertical as in the first, but are curved in an opposite direction. As a necessary consequence of this arrangement of the fibres, the Lecturer showed that when the layers are in apposition, as they exist in the undissected ventricle, the first external layer and the last internal cross each other with a slight deviation from the vertical, as in the letter X ; while in the succeeding external and internal layers, * A sheet of paper with parallel lines drawn upon it will answer the purpose equally well, except that its non-transparency precludes our seeing the external and internal spirals rolled the one within the other when the sheet is fashioned into a cone and held against the light, as the Lecturer recommends. The sheets should be twice as long as they are broad j and the lines or threads should run in the direction of the length. t That is, in the direction from the left hand to the right of the observer. 436 until the fifth or central one, which is transverse, is reached, they cross at successively wider vertical angles, as may be represented by an x placed horizontally. Holding the cone, prepared as described, against the light, the Lecturer then showed how, by the rolling process, a double system of conical spirals, similar to those found in the left ventricle, had been produced — the one an external left-handed down system, running from base to apex, and corresponding with the external layers ; the other an internal right-handed up system, running from apex to base, and corresponding with the internal fibres ; and how, seeing the opposite systems are the result of different portions of the same threads being rolled in different directions (the one within the other), the spirals are consequently continuous at the apex. He in this manner explained the continuity of the external and internal fibres at the apex. By simply producing the threads form- ing the internal spirals, and turning them out at the base until they met corresponding external spirals, he next showed how the con- tinuity of the fibres at the base might be accounted for. The con- nexion of the fibres at the base, he remarked, is effected for the most part as at the apex, by continuity of their proper muscular substance ; but those of the papillary muscles are continued by the tendinous cords. This continuity observes a certain order, so that certain ex- ternal layers are continued at the apex into certain internal layers, and turn outwards at the base into their original external position. Thus the first layer is continuous with the ninth, the second with the eighth, the third with the seventh, and the fourth with the sixth, while the fifth occupies, as already said, the middle place be- tween the four external and four internal. He thus endeavoured to prove that a strong analogy exists between the arrangement of the fibres at the apex and the base, and that the same principle which turns in the external fibres at the apex also turns out the internal at the base, — a view which, while it extends rather than militates against that of older writers, was strongly supported by the arguments he adduced. It would therefore seem that the fibres do not form simple loops pointing towards the apex, as generally supposed, but twisted continuous loops pointing alike to apex and base. From this arrangement, it follows that the first and ninth layers embrace in their convolutions those immediately beneath them, while these in 437 turn embrace those next in succession, and so on until the central layer is reached, — an arrangement which may in part explain alike the rolling movements and powerful action of the ventricles. The Lecturer next drew attention to the manner in which the external fibres pass into the interior of the ventricle to form the musculi papillares. He first remarked that when the external fibres get into the interior they are necessarily confined to a smaller area, and are therefore crowded into a mass of greater thickness, which contributes to form the papillary muscles. He then showed that the external fibres, entering at the apex and forming the "vortex," pass inwards in two principal parcels or bundles, one of which comes chiefly from the posterior surface of the ventricle, and winds for- wards to enter the apex anteriorly, whilst another comes from the anterior surface, and winds backwards to enter the apex posteriorly, a fact which the Lecturer believes has been hitherto overlooked. On entering the cavity, the anterior bundle crosses to the posterior wall, and forms the posterior papillary muscle, whilst the posterior bundle forms the anterior papillary muscle. The fact of this double en- trance, and its relation to the papillary muscles, was shown in various preparations ; and it was remarked that, but for this double entrance, which applies to all the external layers, the apex of the ventricle would be like the barrel of a pen cut slantingly, or, in fact, lop- sided ; whereas, by the arrangement described, it is rendered bilate- rally symmetrical. To bring this bilateral entrance and symmetry into harmony with the description already given of the succession of layers, and with the illustration of the conically rolled sheet, the Lecturer explained that we must regard the primary sheet as having split into two, or we must suppose a second one superadded, and rolled up along with the first. In fact, if a second sheet of net with parallel threads be laid on the first, so that the threads upon it intersect those of the first at an acute angle, and the two are then rolled up together in the way already described, the result will be that the opening at the apex will have two symmetrical lips, as it were, representing the two parcels of fibres forming the vortex in the natural heart. It is well known that the wall of the left ventricle is thickest at about a third of its length from the base, and that from this point it decreases in thickness towards the base, and still more towards the 438 apex, which is its thinnest part. This condition may be explained by a certain modification of the preceding description, — by supposing, namely (what is really the fact), that the outermost and innermost layers extend further towards the apex and towards the base than those which come next, and these again further than those which succeed, and so on with the rest ; the central one being of least ex- tent, and confined indeed to about the middle third of the ventricle. In this way the ventricular wall is thickest towards its middle, where it is composed of all the layers, but becomes thinner and thinner towards the base and apex, where it consists of fewer and fewer layers. Proceeding next to speak of the right ventricle, and especially of its relation to the left, the Lecturer observed that the simplest way to view that ventricle is to regard it as a segment of the left one ; and this view he considers to be most in accordance with what we know of its structure and mode of development. For a short time after the heart appears in the embryo, its ventricular compartment is simple ; but a septum soon begins to rise up within it, which pro- ceeds from the right side of the apex and anterior wall of the cavity in the direction of the base, and is completed about the eighth week of intra-uterine life. For a time, moreover, the new-formed ven- tricles have equally thick walls ; but as the full period is approached, the left, which is destined after birth to perform a larger amount of work, comes to predominate in thickness. Starting now from the left or "typical" ventricle, constituted as above described, the Lecturer showed that, by pushing in the anterior wall in imitation of the constructive process in the embryo until it reaches the posterior wall, two ventricles are produced, with a partition or septum between. As, however, the septum in this case is double and unattached pos- teriorly, he said it was necessary, in order to complete the structure, to suppose the fibres forming the posterior border of the septal duplicature as coalescing or anastomosing with corresponding fibres of the posterior wall, whilst the fibres of the two halves of the dupli- cature itself are blended with each other. In this way, as he ex- plained, there results a single septum connected posteriorly, and constituted in a manner which remarkably accords with the struc- ture discovered by dissecting the adult heart. Thus, when both ventricles are dissected at the same time, the fibres forming the 439 external layers posteriorly are found to be for the most part common to both ; in other words, the fibres on the back part of the left ventricle cross over the posterior coronary tract, and pass on to the right ventricle ; whereas, in front, with the exception of a large cross band at the base, the fibres of the right and of the left ventricle respectively dip inward at the anterior coronary tract, as if altogether independent of each other : an arrangement which induced Winslow to regard the heart as consisting of two muscles enveloped in a third. When, moreover, the so-called common fibres, posteriorly, are dis- sected layer by layer simultaneously with the independent anterior fibres, it is found that both pass through the same changes of direc- tion ; and the same rule holds good with the fibres of the septum. Another possible mode of explaining the septum, as the Lecturer showed, is to regard the layers entering into the formation of the left ventricle as splitting up posteriorly, the one half of each layer winding round to form the right ventricle, and then dipping in front to form the right half of the septum, whilst the other half proceeds immediately forwards to form the left half of the septum. Both ventricles thus appear to be formed on the same general plan, but they differ materially in the structure of their apices ; and the question arises — which is the primary or typical ventricle ? Now, while the fibres of the left ventricle enter its apex in a spiral manner by a species of involution similar to that which would be produced by rolling a sheet of muscle into a cone, those of the right ventricle simply bend or double on themselves. Moreover, as the Lecturer sug- gested, were we to split the septum into two, assigning to each ven- tricle its proper share, and then apply the cut ends of the common fibres (which cross from the left to the right ventricle posteriorly) to their corresponding fibres in the left half of the septum, we should find that we had still a perfect whole — in other words, a complete system of external and internal spirals ; whereas the fibres of the right ventricle and its half of the septum, treated in the same way, would represent only a part of a more complete system — a portion nipped off, as it were, from the side of the perfect cone. Accordingly, if we would dissect the left ventricle, and especially its apex, sym- metrically, we must detach the right ventricle as if it were of no account, and dissect layer after layer of the septum pari passu with the layers of the left ventricular wall generally ; on the other 440 hand, the right ventricle can be dissected only in connexion with the left. For these reasons the Lecturer is inclined to regard the left ven- tricle as the typical one, and the right as a mere segment thereof; and in further corroboration of this opinion, he referred to the shape of the right and left ventricular cavities, as shown by casts of their interior. The left always yields a beautifully finished and perfect right-handed conical screw, while the cast of the right ventricle, although it has the same twist, represents only an incomplete portion. This statement was illustrated by a wax-cast of the ven- tricles of the heart of a deer. In conclusion, the Lecturer remarked that the arrangement of the fibres composing the ventricles of the mammalian heart, as he had endeavoured to expose it, is characterized by comparative simplicity, and harmonizes perfectly with what is known of the heart's move- ments. [The matters touched on by the Lecturer are more fully treated of, and the descriptions copiously illustrated by figures, in his Paper entitled " On the Arrangement of the Muscular Fibres of the Ventricular Portion of the Vertebrate Heart." By JAMES PETTI- GREW, Esq. Communicated by JOHN GOODSIR, Esq., Professor of Anatomy in the University of Edinburgh. Received Nov. 22, 1859.J April 26, 1860. Sir BENJAMIN C. BRODIE, Bart., President, in the Chair. The following communications were read : — I. " Note on Regelation." By MICHAEL FARADAY, D.C.L., F.B.S. &c. Received March 13, 1860. The philosophy of the phenomenon now understood by the word Regelation is exceedingly interesting, not only because of its relation to glacial action under natural circumstances, as shown by Tyndall and others, but also, and as I think especially, in its bearings upon molecular action ; and this is shown, not merely by the desire of dif- 441 ferent philosophers to assign the true physical principle of action, but also by the great differences between the views which they have taken. Two pieces of thawing ice, if put together, adhere and become one ; at a place where liquefaction was proceeding, congelation sud- denly occurs. The effect will take place in air, or in water, or in vacuo. It will occur at every point where the two pieces of ice touch ; but not with ice below the freezing-point, i. e. with dry ice, or ice so cold as to be everywhere in the solid state. Three different views are taken of the nature of this phenomenon. When first observed in 1850, I explained it by supposing that a particle of water, which could retain the liquid state whilst touching ice only on one side, could not retain the liquid state if it were touched by ice on both sides ; but became solid, the general tem- perature remaining the same*. Professor J. Thomson, who dis- covered that pressure lowered the freezing-point of water f, attributed the regelation to the fact that two pieces of ice could not be made to bear on each other without pressure ; and that the pressure, how- ever slight, would cause fusion at the place where the particles touched, accompanied by relief of the pressure and resolidification of the water at the place of contact, in the manner that he has fully explained in a recent communication to the Royal Society^. Profes- sor Forbes assents to neither of these views ; but admitting Person's idea of the gradual liquefaction of ice, and assuming that ice is essentially colder than ice-cold water, i. e. the water in contact with it, he concludes that two wet pieces of ice will have the water be- tween them frozen at the place where they come into contact§. Though some might think that Professor Thomson, in his last communication, was trusting to changes of pressure and tempera- ture so inappreciably small as to be not merely imperceptible, but also ineffectual, still he carried his conditions with him into all the cases he referred to, even though some of his assumed pressures were due to capillary attraction, or to the consequent pressure of the * Researches in Chemistry and Physics, 8vo. pp. 373, 378. t Mousson says that a pressure of 13,000 atmospheres lowers the temperature of freezing from 0° to —18° Cent. J Royal Society Proceedings, vol. x. p. 152. § Proceedings of the Royal Society of Edinburgh, April 19, 1858. 442 atmosphere, only. It seemed to me that experiment might be so applied as to advance the investigation of this beautiful point in molecular philosophy to a further degree than has yet been done ; even to the extent of exhausting the power of some of the principles assumed in one or more of the three views adopted, and so render our knowledge a little more denned and exact than it is at present. In order to exclude all pressure of the particles of ice on each other due to capillary attraction or the atmosphere, I prepared to experiment altogether under water ; and for this purpose arranged a bath of that fluid at 32° F. A pail, surrounded by dry flannel, was placed in a box ; a glass jar, 10 inches deep and 7 inches wide, was placed on a low tripod in the pail ; broken ice was packed be- tween the jar and the pail ; the jar was filled with ice-cold water to within an inch of the top ; a glass dish filled with ice was employed as a cover to it, and the whole enveloped with dry flannel. In this way the central jar, with its contents, could be retained at the un- changing temperature of 32° F. for a week or more ; for a small piece of ice floating in it for that time was not entirely melted away. All that was required to keep the arrangement at the fixed temperature, was to renew the packing ice in the pail from time to time, and also that in the basin cover. A very slow thawing process was going on in the jar the whole time, as was evident by the state of the indi- cating piece of ice there present. Pieces of good Wenham-lake ice were prepared, some being blocks three inches square, and nearly an inch thick, others square prisms four or five inches long : the blocks had each a hole made through them with a hot wire near one corner ; woollen thread passed through these holes formed loops, which being attached to pieces of lead, enabled me to sink the ice entirely under the surface of the ice-cold water. Each piece was thus moored to a particular place, and, be- cause of its buoyancy, assumed a position of stability. The threads were about 1| inch long, so that a piece of ice, when depressed sideways and then left to itself, rose in the water as far as it could, and into its stable position, with considerable force. When, also, a piece was turned round on its loop as a vertical axis, the torsion force tended to make it return in the reverse direction. Two similar blocks of ice were placed in the water with their opposed faces about two inches apart ; they could be moved into 44-3 any desired position by the use of slender rods of wood, without any change of temperature in the water. If brought near to each other and then left unrestrained, they separated, returning to their first position with considerable force. If brought into the slightest contact, regelation ensued, the blocks adhered, and remained ad- herent notwithstanding the force tending to pull them apart. They would continue thus, even for twenty-four hours or more, until they were purposely separated, and would appear (by many trials) to have the adhesion increased at the points where they first touched, though at other parts of the contiguous surfaces a feeble thawing and dissecting action went on. In this case, except for the first moment and in a very minute degree, there was no pressure either from capillary action or any other cause. On the contrary, a tensile force of considerable amount was tending all the time to separate the pieces of ice at their points of adhesion ; where still, I believe, the adhesion went on increasing — a belief that will be fully confirmed hereafter. Being desirous of knowing whether anything like soft adhesion occurred, such as would allow slow change of position without sepa- ration during the action of the tensile force, I made the following arrangements. The blocks of ice being moored by the threads fastened to the lowest corners, stood in the water with one of the diagonals of the large surfaces vertical ; before the faces were brought into contact, each block was rotated 45° about a horizontal axis, in opposite directions, so that when put together, they made a compound block, with horizontal upper edges, each half of which tended to be twisted upon, and torn from the other. Yet by placing indicators in holes previously made in the edges of the ice, I could not find that there was the slightest motion of the blocks in rela- tion to each other in the thirty- six hours during which the experi- ment was continued. This result, as far as it goes, is against the necessity of pressure to regelation, or the existence of any condition like that of softness or a shifting contact ; and yet I shall be able to show that there is either soft adhesion or an equivalent for it, and from that state draw still further cause against the necessity of pres- sure to regelation. Torsion force was then employed as an antagonist to regelation. The ice-blocks, being separate, were adjusted in the water so as to be 444 parallel to each other, and about l£ inch apart. If made to ap- proach each other on one side, by revolution in opposite directions on vertical axes, a piece of paper being between to prevent ice con- tact, the torsion force set up caused them to separate when left to themselves ; but if the paper were away and the ice pieces were brought into contact, by however slight a force, they became one, forming a rigid piece of ice, though the strength was, of course, very small, the point of adhesion and solidification being simply the con- tact of two convex surfaces of small radius. By giving a little motion to the pail, or by moving either piece of ice gently in the water with a slip of wood, it was easy to see that the two pieces were rigidly attached to each other ; and it was also found that, allowing time, there was no more tendency to a changing shape here than in the case quoted above. If now the slip of wood were introduced between the adhering pieces of ice, and applied so as to aid the torsion force of one of the loops, i. e. to increase the separating force, but unequally as respects the two pieces, then the congelation at the point of contact would give way, and the pieces of ice would move in relation to each other. Yet they would not separate ; the piece unrestrained by the stick would not move off by the torsion of its own thread, though, if the stick were withdrawn, it would move back into its first attached position, pulling the second piece with it ; and the two would resume their first associated form, though all the while the torsion of both loops was tending to make the pieces separate. If when the wood was applied to change the mutual position of the two pieces of ice, without separating them, it were retained for a second undisturbed, then the two pieces of ice became fixed rigidly to each other in their new position, and maintained it when the wood was removed, but under a state of restraint ; and when suffi- cient force was applied, by a slight tap of the wood on the ice to break up the rigidity, the two pieces of ice would rearrange them- selves under the torsion force of their respective threads, yet remain united ; and, assuming a new position, would, in a second or less, again become rigid, and remain inflexibly conjoined as before. By managing the continuous motion of one piece of ice, it could be kept associated with the other by a flexible point of attachment for any length of time, could be placed in various angular positions 445 to it, could be made (by retaining it quiescent for a moment) to assume and hold permanently any of these positions when the ex- ternal force was removed., could be changed from that position into a new one, and, within certain limits, could be made to possess at pleasure, and for any length of time, either a flexible or a rigid attach- ment to its associated block of ice. So, regelation includes a flexible adhesion of the particles of ice, and also a rigid adhesion. The transition between these two states takes place when there is no external force like pressure tending to bring the particles of ice together, but, on the contrary, a force of torsion is tending to separate them ; and, if respect be had to the mere point of contact on the two rounded surfaces where the flexible adhesion is exercised, the force which tends to separate them may be esteemed very great. The act of regelation cannot be considered as complete until the junction has become rigid ; and therefore I think that the necessity of pressure for it is altogether excluded. No external pressure can remain (under the circumstances) after the first rigid contact is broken. All the forces which remain tend to separate the pieces of ice ; yet the first flexible adhesions and all the successive rigid adhesions which are made to occur, are as much effects of regelation as those which occur under the greatest pressure. The phenomenon of flexible adhesion under tension looks very much like sticking and tenacity ; and I think it probable that Pro- fessor Forbes will see in it evidence of the truth of his view. I cannot, however, consider the fact as bearing such an interpretation ; because I think it impossible to keep a mixture of snow and water for hours and days together without the temperature of the mixed mass becoming uniform ; which uniformity would be fatal to the explanation. My idea of the flexible and rigid adhesion is this : — Two convex surfaces of ice come together ; the particles of water nearest to the place of contact, and therefore within the efficient sphere of action of those particles of ice which are on both sides of them, solidify ; if the condition of things be left for a moment, that the heat evolved by the solidification may be conducted away and dis- persed, more particles will solidify, and ultimately enough to form a fixed and rigid junction, which will remain until a force sufficiently great to break through it is applied. But if the direction of the force resorted to can be relieved by any hinge-like motion at the 446 point of contact, then I think that the union is broken up among the particles on the opening side of the angle, whilst the particles on the closing side come within the effectual regelation distance ; regelation ensues there and the adhesion is maintained, though in an apparently flexible state. The flexibility appears to me to be due to a series of ruptures on one side of the centre of contact, and of adhesion on the other, — the regelation, which is dependent on the vicinity of the ice surfaces, being transferred as the place of efficient vicinity is changed. That the substance we are considering is as brittle as ice, does not make any difficulty to me in respect of the flexible adhesion ; for if we suppose that the point of contact exists only at one particle, still the angular motion at that point must bring a second particle into contact (to suffer regelation) before separation could occur at the first ; or if, as seems proved by the supervention of the rigid adhesion upon the flexible state, many particles are concerned at once, it is not possible that all these should be broken through by a force applied on one side of the place of adhesion, before particles on the opposite side should have the opportunity of regelation, and so of continuing the adhesion. It is not necessary for the observation of these phenomena that a carefully-arranged water-vessel should be employed. The difference between the flexible and rigid adhesion may be examined very well in air. For this purpose, two of the bars of ice before spoken of, may be hung up horizontally by threads, which may be adjusted to give by torsion any separating force desired ; and when the ends of these bars are brought together, the adhesion of the ice, and the ability of placing these bars at any angle, and causing them to preserve that angle by the rigid adhesion due to regelation, will be rendered evident ; and though the flexible adhesion of the ice cannot in this way be examined alone, because of the capillary attraction due to the film of water on the ice, yet that is easily obviated by plunging the pieces into a dish of water at common temperatures, so that they are entirely under the surface, and repeating the observations there. All the important points regarding the flexible and rigid junction of ice due to regelation, can in this way be readily investigated. It will be understood that, in observing the flexible and rigid state of union, convex surfaces of contact are necessary, so that the contact may be only at one point, If there be several places of contact, 447 apparent rigidity is given to the united mass, though each of the places of contact might be in a flexible and, so to say, adhesive con- dition. It is not at all difficult to arrange a convex surface so that, bearing at two places only on the sides of a depression, it should form a flexible joint in one direction, and a rigid attachment in a direction transverse to the former. It might seem at first sight as if the flexible adhesion of the ice gave us a point to start from in the further investigation of the prin- ciple of pressure. If the application of pressure causes ice to freeze together, the application of tension might be expected to produce the contrary effect, and so cause liquidity and separation at the flexible joint. This, however, does not necessarily follow ; nor do I intend to consider what might be supposed to take place whilst theoretically contemplating that case. I think the changes of temperature and pressure are too infinitesimal to go for anything ; and in illustration of this, will describe the following experiment. Wool is known to adhere to ice in the manner, as I believe, of regelation. Some wool- len thread was boiled in distilled water, so as thoroughly to wet it. Some clean ice was broken up small and mixed with water, so as to produce a soft mass, and, being put into a glass jar clothed in flan- nel that it might keep for some hours, had a linear depression made in the surface, so as to form a little ice-ditch filled with water ; in this depression some filaments of the wetted wool were placed, which, sinking to the bottom, rested on the ice only with the weight which they would have being immersed in water ; yet in the course of two hours these filaments were frozen to the ice. In another case, a small loose ball of the same boiled wool, about half an inch in diameter, was put on to a clean piece of ice ; that into a glass basin ; and the whole wrapped up in flannel and left for twelve hours. At the end of that time it was found that thawing had been going on, and that the wool had melted a hole in the ice, by the heat conducted through it to the ice from the air. The hole was filled with the water and wool, but at the bottom some fibres of the wool were frozen to the ice. Is this remarkable property peculiar to water, or is it general to all bodies ? In respect of water it certainly seems to offer us a glimpse into the joint physical action of many particles, and into the nature of cohesion in that body when it is changing between the solid and VOL. X. 2 I 448 liquid state. I made some experiments on this point. Bismuth was melted and kept at a temperature at which both solid and liquid metal could be present ; then rods of bismuth were introduced, but when they had acquired the temperature of the mixed mass, no adhe- sion could be observed between them. By stirring the metal with wood, it was easy to break up the solid part into small crystalline granules ; but when these were pressed together by wood under the surface, there was not the slightest tendency to cohere, as hail or snow would cohere in water. The same negative result was obtained with the metals tin and lead. Melted nitre appeared at times to show traces of the power ; but, on the whole, I incline to think the effects observed resulted from the circumstance that the solid rods experimented with had not acquired throughout the fusing tempera- ture. Nitre is a body which, like water, expands in solidifying; and it may possess a certain degree of this peculiar power. Glacial acetic acid is not merely without regelating force, but actually presents a contrast to it. A bottle containing five or six ounces, which had remained liquid for many months, was at such a temperature that being stirred briskly with a glass rod crystals began to form in it ; these went on increasing in size and quantity for eight or ten hours. Yet all that time there was not the slightest trace of adhesion amongst them, even when they were pressed together ; and as they came to the surface, the liquid portion tended to withdraw from the faces of the crystals ; as if there were a disinclination of the liquid and solid parts to adhere together. Many salts were tried (without much or any expectation), — crystals of them being brought to bear against each other by torsion force, in their saturated solutions at common temperatures. In this way the following bodies were experimented with : — Nitrates of lead, potassa, soda; sulphates of soda, magnesia, copper, zinc; alum; borax; chloride of ammonium ; ferro-prussiate of potassa; carbonate of soda; acetate of lead ; and tartrate of potassa and soda ; but the results with all were negative. My present conclusion therefore is that the property is special for water ; and that the view I have taken of its physical cause does not appear to be less likely now than at the beginning of this short investigation, and therefore has not sunk in value among the three explanations given. 449 Dr. Tyndall added to one of his papers*, a note of mine " On ice of irregular fusibility " indicating a cause for the difference observed in this respect in different parts of the same piece of ice. The view there taken was strongly confirmed by the effects which occurred in the jar of water at constant temperature described in the beginning of the preceding pages, where, though a thawing process was set up, it was so slow as not to dissolve a cubic inch of ice in six or seven days. The blocks retained entirely under water for several days, became so dissected at the surfaces as to develope the mechanical composition of the masses, and to show that they were composed of parallel layers about the tenth of an inch thick, of greater and lesser fusibility, which layers appear, from other modes of examination, to have been horizontal in the ice whilst in the act of formation. They had no relation to the position of the blocks in the water of my ex- periments, or to the direction of gravity, but had a fixed position in relation to each piece of ice. ADDENDUM, received April 28. The following method of examining the regelation phenomena above described may be acceptable. Take a rather large dish of water at common temperatures. Prepare some flat cakes or bars of ice, from half an inch to an inch thick ; render the edges round, and the upper surface of each piece convex, by holding it against the inside of a warm saucepan cover, or in any other way. When two of these pieces are put into the water they will float, having perfect freedom of motion, and yet only the central part of the upper surface will be above the fluid ; when, therefore, the pieces touch at their edges, the width of the water-surface above the place of contact may be two, three, or four inches, and thus the effect of capillary action be entirely removed. By placing a plate of clean dry wax or spermaceti upon the top of a plate of ice, the latter may be entirely submerged, and the tendency to approximation from capillary action converted into a force of separation. When two or more of such floating pieces of ice are brought together by contact at some point under the water, they adhere ; first with an apparently flexible, and then with a rigid adhe- sion. When five or six pieces are grouped in a contorted shape, as * Philosophical Transactions, 1858, p. 228. 2 i 2 450 an S, and one end piece be moved carefully, all will move with it rigidly ; or, if the force be enough to break through the joint, the rupture will be with a crackling noise, but the pieces will still adhere, and in an instant become rigid again. As the adhesion is only by points, the force applied should not be either too powerful or in the manner of a blow. I find a piece of paper, a small feather, or a camel-hair brush applied under the water very convenient for the purpose. When the point of a floating, wedge-shaped piece of ice is brought under water against the corner or side of another floating piece, it sticks to it like a leech ; if, after a moment, a paper edge be brought down upon the place, a very sensible resistance to the rupture at that place is felt. If the ice be replaced by like rounded pieces of wood or glass, touching under water, nothing of this kind occurs, nor any signs of an effect that could by possibility be referred to capillary action ; and finally, if two floating pieces of ice have separating forces attached to them, as by threads connecting them and two light pen- dulums, pulled more or less in opposite directions, then it will be seen with what power the ice is held together at the place of regelation, when the contact there is either in the flexible or rigid condition, by the velocity and force with which the two pieces will separate when the adhesion is properly and entirely overcome. II. " Notes on the apparent Universality of a Principle analogous to Regelation, on the Physical Nature of Glass, and on the probable existence of Water in a state corresponding to that of Glass." By EDWARD W. BRAYLEY, Esq., F.R.S. &c. Received April 26, 1860. 1 . Recent experimental investigations, and the reasoning founded upon them, have elevated the designation of an observed property of ice to the character of a principle in physics. The growth of crystals of camphor and of iodide of cyanogen, by the deposition of solid matter upon them from an atmosphere unable to deposit like solid matter upon the surrounding glass, except at a lower temperature ; and that of crystals in solution, by the deposition of solid matter upon them which is not deposited elsewhere in the solution, have been adduced by Mr. Faraday to illustrate the extension of the principle 451 of action which is manifested in regelation ; ancl " many such like cases," he remarks, " may be produced." In his reasoning on the nature of that principle, he also rests on the fact, that ice has the same property as camphor, sulphur, phosphorus, metals, &c., which cause the deposition of solid particles upon them from the surrounding fluid, that would not have been so deposited without the presence of the previous solid portions*. In reflecting on these indications of the universality of the cause, whatever it may intrinsically be, which is operative in the phenomena alluded to, it occurred to me that the known fact of the incorpora- tion of two or more plates of glass into one block, presented a curious parallel to the incorporation of two or more slabs or separate portions of ice into one mass ; and to determine in what manner these sub- jects were related to each other appeared to deserve careful investi- gation. Towards this the following suggestions are offered : — Certain substances, both elementary and compound, appear to present, in what we term the solid state, phenomena corresponding to those which are presented by others in the liquid and solid states and the transitions from one to the other collectively regarded, and indicating the existence of a condition of matter which may be termed arrested liquidity, but yet is not, in the most perfect sense, solidity. Of these bodies glass is one. The fact in question, which exemplifies in a striking manner the property here alluded to, appears to have been first noticed as a subject of scientific importance by MM. Pouillet and Clement Desormesf. It is the incorporation, into one mass, of two or more plates of the kind of glass manufactured for mirrors, and called plate-glass, the polished surfaces of which have been placed, and have remained for some considerable time, at common temperatures, in close contact with each other, the entire area of one plate being in contact with the entire area of the contiguous one, — ex- tensive mutual surfaces of contact being thus supplied. Under these circumstances, two, three, or four, or even a greater number of plates become converted into one block of glass, which it is impossible to * Exp. Res. in Chemistry and Physics, pp. 380, 381. f As far as my reading extends, it was first recorded by Pouillet in his ' Ele- mens de Physique/ liv. vi. ch. ii. 2me edit. Paris, 1832, tome iii. p. 41 (Bruxelles, 1836, p. 292). In the fourth edition, Paris, 1844, it appears to be omitted, toge- ther with other and established facts relating both to glass and to metals. 452 separate into the original plates, and which may be worked, and even cut with a diamond, as if the whole had originally been a single mass. In some specimens which I have examined, with the surface of one plate were incorporated portions of another, the surfaces of fracture of which were alone exposed, its substance having been torn through in the effort to separate the united plates by mechanical force*. The same effect took place in some experiments by Clement Desormes. I assume it to be highly probable that the process by which the two plates of glass become one, is, in reality, analogous to that of regelation in ice, and finally dependent on the same principles, whatever their true character may be conceived or shall ultimately be determined to be. To this it may be objected, however, that there is no evidence, in the case of the glass, of the previous lique- faction, or even approach to liquefaction, of the surfaces which become united so as entirely to disappear (or, more properly speaking, to be altogether obliterated), and that the phenomenon is referable simply to the homogeneous attraction of the molecules of one plate for those of the contiguous one, the evenness of the two polished sur- faces allowing them to he brought within a very minute distance of one another. But two remarkable facts greatly diminish the weight of this objection, if, indeed, they do not entirely remove it. First, unpolished plates of glass have no tendency to unite ; the hard and compact siliceous film, to which Prof. Faraday, regarding glass " as a solution of different substances one in another,'5 long ago referred its power of resisting agents generally f, and which previously bound together the outer molecules of each plate, must be removed by grinding and polishing, so as to render the actual surfaces of contact those of portions of the glass the chemical nature and condition of which are such as readily to admit of their rapid mutual action and union into one mass. Secondly, the polished plates sometimes have the forms and configurations of the surfaces of straw and other packing- materials impressed upon them (portions of straw, paper, &c. some- times adhering inseparably to the glass, after having been taken to * These and other facts of a similar nature I adduced as illustrative of the phy- sical nature of glass, in lectures on that substance delivered before the Pharma- ceutical Society of London in the year 1845. See Pharm. Journ. vol. v. (Oct. 1845) pp. 157-160. t Phil. Trans. 1830 ; Exp. Res. in Chem. and Phys. p. 282. 453 hot climates*), in consequence of the soft nature of the substance exposed by the polishing, or of its nature being such as readily to soften by a temperature very much below that of the proper fusion, or even softening, of the glass in its integrity. The state of the in- terior portions of a plate of plate-glass appears, therefore, to be similar to that of glass in general at certain temperatures much below its fusing-point, when it presents such remarkable characters of plasticity, tenacity, and ductility f . Is it possible that a lowering of the melting-point of glass, or of the exposed interior portions of it, by pressure, is concerned in the union of the two plates ? The effect of the mere pressure of the atmo- sphere, ensuing upon the exclusion of the air from between the closely apposed plates, would of course be insignificant in depressing the tem- perature of fusion of the glass ; but the pressure occasioned by the cohesive force — exerted, it will be remembered, through a very small thickness only of the material, — which finally unites two or more plates into one block, would probably be adequate to any conceivable effect of this nature which can be required for the production of the phe- nomenon observed. It may appear at first sight, that the fact that glass belongs to that class of bodies which contract on passing from the liquid to the solid state, and the melting-point of which, therefore, would be ele- vated— not depressed — by pressure, is opposed to this possibility. The objection would be a valid one were we now concerned with glass in a crystalline state. But we are treating of that substance in its familiar and ordinary condition, into which it passes from liqui- dity by a continuous gradation of temperature, through equally continuous states of softness into the solid form, like melted phos- phorus and selenium. I am now tempted to ask, in conclusion of this part of the sub- ject, Are all cases of the union of two apparently solid surfaces of * These particular facts were communicated to me by Mr. Tite, F.R.S., who had himself observed them. t We are reminded by these facts of the view taken by Person, and adopted by Prof. Forbes, of the similarity of the liquefaction of ice to that of fatty bodies or of the metals, " all which in melting pass through intermediate stages of softness or viscosity;" and Sir J. F. W. Herschel (Art. "Meteorology," par. 119, Enc. Brit, eighth edit.), when he terms regelation " a sort of welding," appears to concur in this view. 454 the same substance by cohesive attraction, cases of melting and regelation, an infmitesimally thin film of liquid being momentarily produced and as instantly solidified ? Will two surfaces of perfectly dry ice, at temperatures much below 32°, but under favourable me- chanical circumstances, unite by mere apposition and pressure (which ought to follow from Prof. James Thomson's theory), and thus prove the identity of the acting principle in the two cases of ice and plate- The negative of the last question does not appear to be proved by the fact cited by Faraday and Tyndall, that dry, hard-frozen snow has not the property of becoming compacted into a snow-ball. The cases seem not to be comparable, because the brittleness of the con- stituent crystals of snow when in this state, its porous nature as a whole, and its being consequently pervaded by air, will prevent the required apposition of surfaces. Nor, as I conceive, is it proved by Prof. TyndalPs most instructive experiment of crushing a ball of ice, cooled by carbonic acid and ether, into white and opake hard frag- ments ; for in this also the required apposition of surfaces would be wanting. Further, it may be asked, whether this very experi- ment does not demonstrate the limitation of the lowering of the melting- or freezing-point by pressure ? and if so, there can be no tendency to union at 100° below freezing. In discussing the philosophy of the union of two surfaces of glass, I have alluded to the theory of regelation enunciated by Prof. J. Thomson ; but I wish to be understood as not adopting, exclusively, in these notes, any existing theory on the subject. Admitting the operation of cohesive attraction and consequent pressure in the first instance, the phenomenon, with respect to glass, readily admits of explanation by the original view of Mr. Faraday, which is, " that a film of water must possess the property of freezing when placed between two sets of icy particles, though it will not be affected by a single set of particles." If we regard the two apposed surfaces of glass, each consisting of a thin stratum of particles, taken together, as representing the film of water, then the other strata of particles in contact with them respectively, and making up the entire thick- ness of the plate on each side, will correspond to the two sets of icy particles, the action of which by freezing the film of water effects the union of the two portions of ice, and the phenomenon may be 455 consistently explained in the terms of Mr. Faraday's theory. And here we seem to find points of coincidence between cohesive force, as ordinarily considered, the principle of regelation, arid that particular view of the former which has been announced by Mr. Faraday in accounting for the phenomena presented by and con- nected with the latter. 2. But we are led by the preceding facts and considerations to some further inferences, if not indeed to a definite hypothesis, upon the subject of the molecular constitution or physical nature of glass. Mr. Faraday's view of it has been cited already ; he regards glass, it will be remembered, " as a solution of different substances one in another." Professor Maskelyne has suggested to me, in conversa- tion, that the physical nature of glass most probably nearly re- sembles that of a solution of a crystallizable salt in water, imme- diately before crystallizing. These views are evidently coherent, and they harmonize with Prof. Graham's, who defines glass, che- mically, as "a mixture of silicates*." But they all relate to the varieties of glass in common use, while we are concerned, at present, with the abstract vitreous condition of matter, such as it is repre- sented by the phosphoric and boracic acids, probably by the heavy optical glass of Faraday, by the simple glasses of felspar and peri- dote obtained by Charles Deville, by the glassy condition of silica, natural and artificial, and still more perfectly, perhaps, by the glassy form of sugar. Bearing in mind then the homogeneous, or comparatively homo- geneous, nature of these glasses, and considering the uniformity of texture which the acoustic as well as the optical characters of per- fect glass in general evince, especially when contrasted with that of * These views of Mr. Faraday, Mr. Maskelyne, and Mr. Graham are confirmed by the experimental evidence of the structure of glass obtained by Leydolt, to whose researches Professor W. H. Miller of Cambridge had the kindness to direct me. By etching the surface of glass, he found it to have a porphyritic structure, consisting of crystals imbedded in an amorphous substance. But the peculiar characters of glass, especially its relations to sound and light, evince, as indicated in the sequel, that it is not a congeries of ready-formed crystals, though in all probability crystals will always be found on its surface. The amorphous substance recognized by Leydolt will answer, nearly, to what I shall call " simple glass." Other facts which he observed are perfectly in harmony with our pre- vious knowledge of the dependence of the texture of glass upon the rate of cooling. See Comptes Rendus, tome xxxiv. (1852, April 12) p. 565. 456 crystalline plates in the acoustic researches of Savart, and how strongly distinguished that texture is from a crystalline texture or structure, — a nearer analogy than that of a solution ready to cry- stallize, I think, will be found in the condition of water cooled below the freezing-point but still remaining liquid, until by a tremor, or the percussive contact of a solid body, or the mere contact of a crystal of ice, its temperature rises to 32° and it becomes ice. If so, glass will be a substance in which this state of arrested liquidity, or potential solidity, is permanent. And this inference will harmonize with known facts. Gregory Watt proved that heat is evolved when mineral glasses crystallize or become (permanently and truly) solid *. The preparation of sugar called barley-sugar is the vitreous condi- tion of that body, already taken as a type of simple glass ; while granular sugar, and more perfectly sugar-candy, exhibit its crystal- line state. Prof. Graham has shown that, at a certain temperature, by mechanical means the former may be converted into the latter, the temperature quickly rising 70° on the transition of the sugar from the glassy to the crystalline state. This and similar facts in- duced him to refer the peculiar constitution and properties of glass in general to the permanent retention of a certain quantity of heat in a latent state, which becomes sensible on its crystallization ; and this will take place on its being preserved in a soft state at certain temperatures. There are some remarkable and instructive parallels between the phenomena of the crystallization of water, and that of glass and some other bodies. It follows from the experiments and inductions of Gregory Watt already cited, that during the crystallization of glass a higher temperature must be communicated to the interior than that existing over its surface, by the evolution of heat at the points where the crystalline form is assumed, which will be gradually conducted throughout the mass. So that, in the express words of Faraday, in relation to ice, " by virtue of the solidifying [crystal- lizing] power at points of contact, the same mass may be freezing and thawing at the same moment ;" and the " freezing process in the inside may be a thawing process on the outside," and thus contribute to the slowness of the cooling, and allow the crystallization therefore to be the more perfect. We here seem to have the explanation * Phil. Trans. 1804, pp. 285-290. 457 of the well-known fact, that in bodies which crystallize from a state of igneous fusion, the most perfect crystalline state is produced when the longest time intervenes between the commencement of solidification (now using that term in its ordinary sense) and the complete cooling of the melted mass. The cases cited from Mr. Faraday at the beginning of this paper, of the growth of crystals (including those of ice in ice-cold water) in solutions, all have their exact parallels in the accretion of crystals in cooling melted glass. " Crystals of ice," Mr. Faraday observes, " which could not be colder than the surrounding fluid, exhibited the phenomena of regelation " — that is, of incorporation into one — " when purposely brought in contact with each other." The same thing happens with melted glass slowly cooling, in which crystalline spherules, often forming spontaneously and independently, continue to form and to increase, even after the glass has become solid as such, by the operation of a principle in this view analogous to regelation, until the entire mass has become crystalline*. 3. No crystalline body has been longer or more extensively subject to human observation, than crystallized water, or ice. Its natural history and properties, as science has advanced, have been investi- gated with increasing generality and precision ; and they have finally become objects of that systematic and exact research which charac- terizes the present era of physical inquiry, — as is evinced by the dis- * If we should prefer to adopt Mr. Maskelyne's suggestion in a formal manner, and regard glass as resembling a solution about to crystallize, its analogue, agreeably to the preceding views, will be a saturated solution of a salt in hot water, allowed to cool undisturbed, and remaining fluid, until its cohesion is affected, when its temperature rises, and the salt crystallizes. Specimens of glass are common which have the aspect and distribution of parts of a crystallized salt in the mother-liquor ; opake crystallized spherules appearing in the midst of a transparent mass. To these correspond, among natural glasses, pitchstone and many examples of porphyritic obsidian, consisting of a vitreous base in which crystals have been formed and are imbedded. But at the same time the view I have taken of the subject, and Mr. Maskelyne's, may be equally tenable ; for the state of water remaining liquid at temperatures below 32°, and that of saline solutions remaining un crystallized at temperatures below those of solidification, are evidently closely analogous. Should I return to this subject, I shall refer to my friend Mr. Sorby's observa- tions on the nature of glass, which I had not read when these notes were com- municated to the Royal Society, but which are in entire agreement with the views I have suggested. — See Quart. Journ. of Geol. Soc. vol. xiv. p. 465. 458 cussion on regelation, to which these notes are intended to be sup- plementary. A most remarkable deficiency, however, still remains, apparently, in our knowledge of this substance : — Water in the vitreous condition — Ice-glass — has never been observed. While we know the antithetical vitreous state of so many different cry- stallized substances — minerals produced by heat, salts deposited from aqueous solution, neutral bodies of organic origin — and have great reason to believe that that antithetical condition to crystallization is universal, we have no knowledge of it in relation to water or ice. My own attention has been awake to the subject, without success, for many years. It would seem to be scarcely within the bounds of possibility that the glassy state of water, if possessing what we term solidity, should not, ere now, either have been observed in nature, or have occurred and been recognized in experimental research*. I now venture to submit the inquiry, Does this apparent deficiency in our knowledge exist because — to use language recently introduced into physical science — the homologue of the glassy state of water is not what we ordinarily term solid — because the state of water cooled below 32° but still liquid is in fact the state which corresponds to the vitreous condition of other bodies, and to the physical nature of perfect ordinary glass ? Is the one simply a case of potential soli- dity, and the other of the confluent or equivalent state of arrested liquidity ? It may be said that the homology which is here endeavoured to be established between liquid water below 32° and glass, is a forced one. That, in relation to each other, these are extreme cases is perfectly true ; but intermediate terms of the series are not wanting, and some of them are supplied by sulphur and phosphorus, and in a remark- able manner by selenium. All these bodies, when melted, may be * The crushed fragments of the ball of ice cooled in carbonic acid and ether, in Prof. Tyndall's experiment already mentioned, which " remained white and opake as those of crushed glass," were still, he informs me, perfectly crystalline, resembling fragments of quartz. The " points of analogy between the molecular structure of ice and glass " noticed by Mr. Drummond (Phil. Mag., August 1859, S. 4. vol.xviii. pp. 102-103) do not involve the physical condition of those bodies, but relate merely to the resemblance of one crystallized substance (ice) to another (Reaumur's porcelain), and of both to a third body (bottle- and window-glass), which, from its optical characters, is inferred — I think inconsequentially — to have assumed a state pre- paratory to crystallization. 459 cooled many degrees below their freezing-points and yet remain fluid. Sulphur presents, in its viscid form, an approach to the glassy con- dition ; but it may be obtained in the crystalline form on passing from a state of fusion, and when cooled below freezing, instantaneously crystallizes, like water, by mechanical disturbance. In phosphorus also there is the viscid state ; and when cooling after fusion, it passes gradually, like glass, from the liquid to the solid con- dition without crystallizing, though crystals are deposited from some of its solutions. Selenium presents a state resembling the viscid state of the preceding substances ; but when melted, and left to cool, remains fluid below its melting-point, and solidifies very gradually in its amorphous state (in which it has some of the characteristic pro- perties of glass), and a thermometer immersed in it during the cool- ing does not remain stationary at any point, or indicate any tempe- rature at which heat is evolved by molecular change in the substance, — as if the selenium passed continuously from the liquid glassy state to that of solid glass. At ordinary temperatures it retains this con- dition for a long time — as common glass does at higher, and as water and sulphur will at lower temperatures; but when heated again, between a certain temperature and its melting-point it becomes cry- stalline and gives out great heat*. When glass is raised to a certain temperature, and by its maintenence is preserved in a soft state, it does the same. In sulphur, phosphorus, and selenium, therefore, the fluid state below the temperature of solidification — the intermediate condition between fluidity and solidity — the viscid state long retained — the * These properties of selenium are here stated on the authority of Hittorff, cited in Graham's ' Elements of Chemistry/ second edition, vol. ii. pp. 688, 689. The case of vanadic acid strongly resembles that of selenium, but extends this series of concurrent phenomena to a range of temperatures nearly approaching those which govern the molecular changes of glass. It fuses at a red heat, and crystallizes on cooling, but femains fluid below its freezing-point. At the mo- ment solidification commences, it again becomes red-hot, and remains so as long as crystallization continues. The crystallization of glass, it has been seen, takes place at a high temperature, from the ordinary state of solidity, heat being evolved. So the glassy variety of gadolinite (like glass, a silicate with a compound base), when its temperature is elevated above redness, remains solid, but evolves heat (becoming incandescent), and crystallizes ; while the crystalline variety merely fuses and intumesces when similarly treated. 460 solid state of selenium which evolves heat on crystallizing — all ap- pear to be homologues, at once, of liquid water below 32°, and of the glassy state of matter. Should this hypothesis be verified, water below 32°, or rather, per- haps, from the temperature of maximum density downwards through that of freezing, may have to be regarded as the type of the vitreous condition of matter ; and the causes of the peculiar characters of that condition, its effects on the transmission of the vibrations of sound and light, the conchoidal fracture, &c., may have to be dis- covered by researches on its molecular nature. III. " On the Effect of the presence of Metals and Metalloids upon the Electric Conductivity of Pure Copper." By A. MATTHIESSEN, Esq., and M. HOLZMANN, Esq. Communi- cated by Professor WHEATSTONE. Received March 14, 1860. (Abstract.) After studying the effect of suboxide of copper, phosphorus, arsenic, sulphur, carbon, tin, zinc, iron, lead, silver, gold, &c., on the conducting power of pure copper, we have come to the conclusion that there is no alloy of copper which conducts electricity better than the pure metal. May 3, 1860. Sir BENJAMIN C. BRODIE, Bart., President, in the Chair. In accordance with the Statutes, the Secretary read the names of the Candidates recommended by the Council for Election into the Society, viz. — Frederick Augustus Abel, Esq. Thomas Baring, Esq., M.P. John Frederic Bateman, Esq. Edward Brown-Sequard, M.D. Richard C. Carrington, Esq. Francis Galton, Esq. Joseph Henry Gilbert, Esq. Thomas Hewitt Key, Esq. Joseph Lister, Esq. Rev. Robert Main, M.A. Robert William Mylne, Esq. Roundell Palmer, Esq., Q.C. John Thomas Quekett, Esq. Edward Smith, M.D. Sir William Jardine, Bart. The following communications were read : — 461 I. "On the relations between the Elastic Force of Aqueous Vapour, at ordinary temperatures, and its Motive Force in producing Currents of Air in Vertical Tubes." By W. D. CHOWNE, M.D., F.R.C.P. Communicated by JOHN BISHOP, Esq. Received March 15, 1860. (Abstract.) In 1853 the author of this communication made a considerable number of experiments which demonstrated that when a tube, open at both ends, was placed vertically in the undisturbed atmosphere of a closed room, there was an upward movement of the air within the tube of sufficient force to keep an anemometer of light weight in a state of constant revolution, though with a variable velocity. An abstract of the results of these experiments was printed in the ' Pro- ceedings' of the Society for June 1855. In order to further investigate the immediate cause or nature of the force which set the machine in motion, the author instituted a series of fresh experiments. These experiments were made in the room described in the former communication, guarded in the same manner against disturbing causes, and with such extra precautions as will be hereafter explained. The apparatus used was a tube 96 inches long and 6 '75 inches uniform diameter, the material zinc. The upper extremity was open to its full extent; at the lower, the aperture was a lateral one only, into which a piece of zinc tube 3 inches in diameter, and bent once at right angles, was accurately fitted with the outer orifice upward. Within this orifice, which was about 5 inches above the level of the floor, an anemometer, described in the former paper, and weighing 7 grains, was placed in the horizontal position. About midway between the upper and the lower extremity of the tube, a very delicate differential thermometer was firmly and permanently fixed, with one bulb outside and the other inside, and the aperture through which the latter was inserted completely closed. The scale was on the stem of the outer bulb. The results of a long series of observations were recorded. The state of the dry and the wet bulb of the hygrometer, as well as the indications of the differential thermometer, was noted, in connexion with the number of revolutions performed per minute by the ane- 462 mometer. While the differential thermometer indicated the same relative differences hetween the heat of the atmosphere within and without the tube, the velocity of the revolutions was found to vary considerably. This variation was discovered to be chiefly, if not wholly, dependent on the elasticity of vapour, due to the hygro- metrical state of the atmosphere, as estimated from the dry- and the wet-bulb thermometers, and calculated from the tables of Regnault. 240 observations were recorded and afterwards separated into groups, each group comprising those in which the differential ther- mometer gave the same indication. If in either of these groups we separate into two classes the cases in which the elasticity was highest, from the cases in which it was lowest, and multiply the mean of each with the corresponding mean of the number of the revolutions of the anemometer, their product is nearly a constant, thus showing that the velocity of ascent of the atmospheric vapour is inversely as its elasticity ; and hence it follows that the velocity of the ascending current in the tube varies inversely as the density or elastic force of the vapour suspended in the atmo- sphere. This was rendered evident by the aid of Tables appended to the paper. When the mean elastic force of vapour calculated from the dry and the wet bulbs is multiplied by the constant, 13*83, the result gives the whole amount of water in a vertical column of the atmo- sphere in inches ; it follows therefore that when the difference of temperature between the external air and that in the tube, as shown by the differential thermometer, is constant, the velocity of the current in the tube varies inversely as the weight of the vapour suspended in the atmosphere. In an Appendix the author describes some additional experiments, made with the view of ascertaining whether the readings of the differential thermometer were mainly due to actual changes of tem- perature within the tube, or to extraneous causes acting on the external bulb. He found that when the external bulb was covered with woollen cloth or protected by a zinc tube of about 4 inches diameter and 6 inches long, the temperature of the bulb was increased about 2° on the scale of the instrument, and that when they were removed the prior reading was restored, while the number of revolutions of the anemometer per minute was not appreciably 463 affected by the change. This explains why the readings of the dif- ferential thermometer varied from 33°'0 to 33°- 5 as described in the paper, without producing a corresponding change in the velocity of the anemometer. For the purpose of obtaining a more correct estimate of the influence of a given increase of heat within the tube, the author introduced into the tube at its lowest extremity, a phial containing eight ounces of water at the temperature of 100° Fahr., corked so that no vapour could escape. The result showed that in thirteen observations a quantity of heat equal to an increase of one-tenth of a degree on the scale of the differential thermometer, was equivalent to a mean velocity of the anemometer of 3*6 revolutions per minute, the greatest number being 3*8, the least 3 '3 per minute. These observations render it still more evident, that if a higher temperature within the tube had been the main cause of the revolu- tions of the anemometer, the variations in their velocity would not have been in such exact relation to the elastic force of the atmo- spheric vapour, as has been shown to be the case. They also lead to the inference, that the apparent excess of heat within the tube alluded to by the author in his Paper read before the Society in 1855 did not really exist, and to the conclusion that, if such excess had been present, the anemometer would not have been brought to a state of rest by depriving the air of the room of a portion of the moisture ordinarily suspended in it. II. "On the Relation between Boiling-point and Composition in Organic Compounds." By HERMANN KOPP, Esq. Com- municated by Dr. HOFMANN. Received March 20, 1860. (Abstract.) The author was the first to observe (in 1841) that, on comparing pairs of analogous organic compounds, the same difference in boiling-point corresponds frequently to the same difference in composition. This relation between boiling-point and composition, when first pointed out, was repeatedly denied, but is now generally admitted. The con- tinued experiments of the author, as well as of numerous other inquirers, have since fixed many boiling-points which had hitherto VOL. x. 2 K 464 remained undetermined, and corrected such as had been inaccu- rately observed. In the present paper the author has collected his experimental determinations, and has given a survey of all the facts satisfactorily established up to the present moment regarding the relations between boiling-point and composition. The several propositions previously announced by the author were : — 1. An alcohol, CnHw+2O2, differing in composition from ethylic alcohol (C4H6O2, boiling at 78° C.) by x C2H2, more or less, boils #X 19° higher or lower than ethylic alcohol. 2. The boiling-point of an acid, C»HnO4, is 40° higher than that of the corresponding alcohol, CwHn+2O2. 3. The boiling-point of a compound ether is 82° higher than the boiling-point of the isomeric acid, C»HnO4. These propositions supply the means of calculating the boiling- points of all alcohols, CnHw+2O2 ; of all acids, CnHnO4 ; of all com- pound ethers, CWHWO4. The author contrasts the values thus cal- culated for these substances with the available results of direct obser- vation. The Table embraces eight alcohols, CnHw+2O2, nine acids, C«HnO4, and twenty-three compound ethers, CnHwO4; the calculated boiling-points agree, as a general rule, with those obtained by experi- ment, as well as two boiling-points of one and the same substance determined by different observers. We are thus justified in assuming that the calculated boiling-point of other alcohols, acids, and ethers belonging to this series will also be found to coincide with the results of observation. The boiling-points of other monatomic alcohols, CwHmO2, other monatomic acids, CWHTOO4, and other compound ethers, CnHmO4, are closely allied with the series previously discussed. A substance containing xC more or less than the analogous term of the previous class, in which the same number of oxygen and of hydrogen equiva- lents is present, boils xx 14°*5 higher or lower ; or, what amounts to the same thing, a difference of #H more or less of hydrogen lowers or raises the boiling-point by ^x5°. Thus benzoic acid, CUH6O4, boils 8 x 14°- 5 higher than propionic acid, C6H6O4, or 8 x 5° higher than renanthylic acid, C14H14O4 ; cinnamate of ethyl, C22H12O4, boils 10 x 14°' 5 higher than butyrate of ethyl, C12H12O4, or 10 X 5° higher than pelargonate of ethyl, C22H22O4. 465 The author compares the boiling-points thus calculated for five alcohols, Cn HmO4; for six acids, CnHmO4; and for sixteen compound ethers, CwHmO4, with the results of observation. In almost all cases the concordance is sufficient. The author demonstrates in the next place that in many series of compounds other than those hitherto considered, the elementary difference, #C2 H2, likewise involves a difference of x x 1 9° in the boil- ing-point. He further shows that on comparing the boiling-points of the corresponding terms in the several series of homologous sub- stances hitherto considered, many other constant differences in boiling- point are found to correspond to certain differences in composition. Thus a monobasic acid is found to boil 44° higher than its ethyl compound, and 63° higher than its methyl compound ; and this con- stant relation holds good even for acids other than those previously examined, e. g. for the substitution-products of acetic acid. Also in substances which are not acids, the substitution of C4H5 or C2H3 for H, occasionally involves a depression of the boiling-points re- spectively of 44° and 63° ; the relation, however, is by no means generally observed. The author, in addition to the examples previously quoted, shows that compounds containing benzoyl (CUH5O2) and benzyl (C14H7) boil 78° (=4 X 14°'5-f 4 X 5°) higher than the corresponding terms containing valeryl (C10H9O2) and amyl (C10Hn), a relation, however, which is likewise not generally met with. He discusses, moreover, other coincidences and differences of boiling-points of compounds differing in a like manner in composition. Not in all homologous series does the elementary difference #C2H2 involve a difference of x x 19° in boiling-point. The author shows that this difference is greater for the hydrocarbons, C»HW_6 and CnH»+2 ; for the acetones and aldehydes, C»HnO2 ; for the so-called simple and mixed ethers, CwHn+2O2 ; for the chlorides, bromides, and iodides of the alcohol radicals, CnHn^ i, and for several other groups ; that it is, on the con- trary, smaller for the anhydrides of monobasic acids, CnHn_2O6 ; for the ethers, C»Hw_2Os (which may be formed either by the action of one molecule of a dibasic acid, C»Hn_2O8, upon two molecules of a monatomic alcohol, CnH«+2O2, or by the action of two molecules of a monobasic acid, CnHnO4, upon one molecule of a diatomic alcohol, CMHW+2O4), and several other series. 2K2 466 The author thinks that the unequal differences in boiling-points corresponding in different homologous series to the elementary differ- ence #C2H2, are probably regulated by a more general law, which will be found when the boiling-points of many substances shall have been determined under pressures differing from those of the atmosphere. "From the observations at present at our disposal it may be affirmed as a general rule, that in homologous compounds belonging to the same series, the differences in boiling-points are proportional to the differences in the formulae. Exceptions obtain only in cases when terms of a particular group are rather difficult to prepare, or when the substances boil at a very high temperature, at which the observations now at our command are for the most part uncertain. Again, it may be affirmed that the difference in boiling-points, corresponding to the elementary difference C2H2, is in a great many series =19° ; in some series greater, in some series less." The author proceeds to discuss the boiling-points of isomeric com- pounds. He shows that in a great many cases isomeric compounds belonging to the same type, and exhibiting the same chemical cha- racter, boil at the same temperature, and that there is no reason why, for the class of bodies mentioned, this coincidence should not obtain generally. On the other hand, different boiling-points are observed in isomeric compounds possessing a different chemical character, although belonging to the same type (e. g. acids and compound ethers, CnHnO . . . H"0 Summing these quantities we have, i and for the means, ..... (D., 477 In this case 0 is the mean of n— 1 observations, of which 24 give the true means for the total solar influence, and the remaining n — 25 being equally distributed through the hour-angles also give the mean approximately. Instead, however, of combining the observations in this way, the following method has been preferred. Let, in the quantities (B), Then H'0+A'0+ ^ _ (H0)= h'0 + «)=< H"T + A"0 + x\- (HT) = A"0+ (^I)=^'o H -\-h -4-x — CH )=A -\-(x ) =G? 23 0 23 V 23X 0 v 23 ' I Summing the last two columns, we have , n—l n—l Similarly we obtain l , n — 1 w— 1 It will be observed that in these summations there are two assump- tions ; one, that the lunar diurnal law is constant throughout the lunation, or series of lunations, for which the means are obtained ; or that the quantity ([ in the expressions (B) is constant. If this be not exact, then the quantity — will contain the variation due to this cause, and depend in part on the lunar hour-angle ; so that the mean (H) which is employed in taking the differences will eliminate part of the lunar action and partially distort the law. The other assump- tion is that the mean solar diurnal variation, represented by (HJ/H^ . . . . , is nearly constant throughout the period ; for, if not, the dif- ferences due to such changes might be sufficient to mask any lunar law, the latter having a small range compared with the former. Also it should be remarked that the means h0, hlt &c. are combined with the irregular effect 23^ . This effect, as far as it is due to n— 1 478 disturbance, we know obeys a solar diurnal law ; and if independent of lunar action, a sufficiently large series of observations might suffice to eliminate it, as combining with and forming part of the regular solar diurnal variation. If, however, the series is not very large and the irregular disturbance considerable compared with the variation sought, it may be desirable to omit or modify the marked irregu- larities. As regards the first assumption referred to above, the results obtained hitherto seem to show the error to be small, and the only way to determine its amount will be to consider it zero in the first instance, and thereafter a more accurate calculus may be employed. For the second assumption, it is certain that the solar diurnal law varies considerably in some cases within a lunation. At the mag- netic equator, for example, the law of magnetic declination is inverted within a few weeks near the equinoxes. The attempt to correct the error due to considerable change in the solar diurnal variation by taking the means, as has been done, from shorter periods than a lunation, is liable to the serious objection that the resulting hourly means are affected unequally by the lunar action, so that the sums (A) take the form, where the second term in each expression is a variable. In the discussion to which I am about to allude, the following plan has been followed. The hourly means for the following series of weeks were taken, namely — ml from 1st, 2nd, 3rd, and 4th weeks of the year. m2 „ 2nd, 3rd, 4th, and 5th „ „ m3 „ 3rd, 4th, 5th, and 6th „ ,, The means of ml and m2 were then taken as normals for the 3rd or middle week, of m2 and m3 as normals for the 4th week, and so on : these means were then employed for the differences from the corresponding hourly observations of the weeks to which they belonged. With reference to the irregular effect, it is evidently desirable that we should know in the first instance whether it may not be a function of the lunar, as well as of the solar, hour- angle ; for this end it is 479 essential in the first instance to obtain the result including all the supposed irregular actions, and afterwards to eliminate these in the best manner possible. In the discussion of the Makerstoun Observations I had substi- tuted for certain observations, which gave differences from the mean beyond a fixed limit, values derived by interpolation from pre- ceding and succeeding observations. General Sabirie in his discussions has rejected wholly the observations which exceeded the limit chosen by him. The omission of observations accidentally or intentionally, and the taking of means without any attempt to supply the omitted observations by approximate values, require consideration. Let m be the true hourly mean for an hour h, derived from the complete series of n observations ; let m' be the mean derived from n— 1 observations, one observation o being accidentally lost ; then nm — o M = r> n — 1 m — o =m n — 1 If, however, we supply the omitted observation by an interpolation between the preceding and succeeding observations, and if the inter- polated value be o + oc, we have nm+oc m'f=— — , n m=-m" -- . n The comparative errors of m1 and m" are therefore o— m _ x - r and — . n — 1 n We may for any given class of observation determine the mean values of these errors. Example : — At Hobarton, in July 1846, the mean barometer for 3h (Hobarton mean time) was 29'848 in., and the mean differ- ence of an observation at that hour from the mean for the hour was 0-403 in. ; if an observation had been omitted with such a difference, or for which o — m=0'403 in., we should have an error in the resulting mean of -~-=0'016 in., and the error might have been twice as great had the observation with the greatest difference been rejected. If we now seek the error of m", where the observation is interpolated, VOL. X. 2 L 480 we shall find for the same month that the mean value of #=0'005 in. nearly; whence the error -= ofi =0*0002 in. only, and the error n .40 would never exceed O'OOl in. A similar though less advantageous result will be found in all classes of hourly observations. In the case where observations are rejected which differ from the mean for the corresponding hour more than a given quantity, let us suppose, to simplify the question, that the sums of n — 1 out of n observations for each of two successive hours are each equal M, and that the observations for the same hours of the rath day are respectively m' + l and m' + l+tf; where »*'=— ^|» 1 'IS ^e ^m^ beyond which observations are rejected, and x is the excess of the observation to be omitted. The means retaining all the observations are f i '• "W n " but if we reject the observation m1 -\-l-\-x, we have m'=— = m' It is assumed that »z/— «wa' = 0 (any other hypothesis of variation would give the same final result), and therefore the error of the change from the first hour to the second, when all the observations are retained, is - ; but if the observation be rejected, the change is m(-\ m'=—. n n This error, therefore, will be greater than the other if I >x ; so that the error in the resulting change from one hour to the next will be less by retaining an observation than by rejecting it, if the difference from the preceding observation be not greater than the difference from the hourly mean ; that this will most frequently be the case will be obvious from the following fact : — At Makerstoun, in 1 844, at 1 A.M. the number of observations which exceeded the monthly means by 3' and less than double that, or 6', was 99, while the whole number which exceeded by more than 6' was only 16. It will be evident also that the difference / of an observation from the corresponding hourly mean may not be due to irregular causes, 481 or to causes which affect the changes from one hour to the next in a perceptible manner, but to gradual and regular daily change. If we examine the daily means most free from irregular or intermittent disturbance, we shall find that they vary plus or minus of the monthly mean ; if the difference amounts to I in any case, then the whole observations of the day may be rejected though they follow the nor- mal law. By taking a proper value of I this case may not happen fre- quently,but cases like the following will. At Hobarton the daily means of magnetic declination differ in some months from the monthly means by 2'*0 nearly ; as the limit chosen by General Sabine is 2''4, any observation in such days differing by 0'*4 from the normal mean would be rejected. The 25th and 26th days of March 1844 had been chosen by me as days free from magnetic disturbance, and fol- lowing the normal law at Makerstoun (Mak. Obs. 1844, p. 339), yet the means of horizontal force for these days differed 0*00064 and 0*00075 from the monthly means ; had the former quantity been the limit, all the observations on these days might have been rejected. Altogether it appears to me that the method of rejecting observa- tions beyond certain limits should not be employed at all, or if employed, only when interpolated observations are substituted ; and that this interpolation should constitute a second part of the discus- sion, the first including all the observations*. These considerations may appear somewhat elementary, but it is essential that results which present such anomalies as the lunar diurnal variation of magnetic declination should be obtained in a manner the most free from objection, even though the objections should touch on quantities of a second order compared with those obtained. The discussion of which I now proceed to note the results, includes all the hourly observations without exception, made in the Trevandrum Observatory (within a degree and a half of the magnetic equator) during the five years 1854 to 1858 ; the second part of the discussion, in which days of great magnetic irregularity have been * I should note here my belief that a peculiarity noticed by General Sabine in his discussions as requiring explanation, namely, that the excursions of the decli- nation needle east and west in the lunar diurnal variation have very different magnitudes, is due to the rejection of observations, while the means by which the differences were obtained included the rejected quantities. 2L2 482 wholly rejected, not being completed, I shall reserve the details for a more formal communication to the Royal Society. The results obtained are as follows : — 1st. At the magnetic equator the lunar diurnal law of magnetic declination varies with the moon's declination and with the sun's declination. 2nd. This variation is so considerable that the attempt to combine all the observations to form the mean law for the year gives results that are not true for any period. Hence evidently the impossibility of relating the laws at different places. The so-called mean law for the year at Trevandrum obtained for. the moon furthest north, on the equator going south, furthest south, and on the equator going north, consists of three maxima and three minima, — a result wholly false, excepting as an arithmetical operation due to combination of very different laws. 3rd. The lunar diurnal law varies chiefly with the position of the sun, the variation being comparatively small with the position of the moon. 4th. At the magnetic equator the range of the variations is mark- edly greatest in the months of January, February, November and December, or about perihelion. The following results are derived after grouping the means for differ- ent positions of the moon in periods of six months, October to March, and April to September ; they are therefore, for the reason given in the 2nd conclusion, not quite accurate ; but the change of the law from month to month will be followed when the details are presented to the Society. The following will give a general idea of the changes : — 5th. When the moon is furthest north. a. About perihelion. The lunar diurnal law of magnetic declina- tion consists of two maxima* when the moon is near the upper and lower meridians, the maximum for the latter being much the great- est ; of the two minima at intermediate epochs, that for the setting moon is the most marked. b. About aphelion. The law consists of two nearly equal minima near the upper and lower transits : of the two intermediate maxima, that near the moonset is the most marked. c. Thus the law about the winter solstice is inverted about the * The declination is easterly at Trevandrum, and the maxima indicate greater easterly declination. 483 summer solstice, and the one law passes into the other at the epochs of the equinoxes, exactly as for the solar diurnal variation. 6th. For the moon on the equator going south. a. About perihelion. The lunar diurnal law consists of two nearly equal maxima near the superior and inferior transits : of the two intermediate minima, the moonset minimum is by far the most marked. b. AJbout aphelion. The law consists of two nearly equal minima near the superior and inferior transits : of the two intermediate maxima, that near moonrise is by far the most marked. c. In this case also the laws for the solstices are the opposite of each other, and the one law passes into the other near the epochs of the equinoxes. 7th. For the moon furthest south. a. About perihelion. The lunar diurnal law consists of maxima near the upper and lower transits, that at the upper transit being by far the most marked : of the intermediate minima, that near moon- set is the greater. b. About aphelion. The law consists of two minima, the most marked at the inferior transit, the other about three hours before the superior transit ; and of two equal maxima, one near moonrise, the other near the superior transit, but varying little till 3 hours before the inferior passage. c. In this instance the inversion is not so complete as in the other cases ; this, it is believed, will be found to be due to the fact that the change from one law to the other takes place after the vernal and before the autumnal equinox ; so that in the means for six months, from which the above conclusions are drawn, the lunations following the law a are combined with those belonging to b. 8th. The moon on the equator going north. a. About perihelion. The lunar diurnal law consists of two nearly equal maxima when the moon is near the superior and inferior meri- dians ; of the two intermediate minima, that near moonrise is by far the most marked. b. About aphelion. The law consists of two minima at the infe- rior and superior transits ; and of two maxima, the greatest at moon- set, the other between the meridians of 16h and 21h; between these points there is an inflexion constituting a slight minimum. 484 c. In this case also the opposition of the laws is sufficiently well marked ; the only divergence from opposition heing that due to the minor minimum about the meridian of 1 9h, due, it is believed, as noted 7th c, to the partial combination of opposite laws in the aphelion half-year. 9th. It will be observed that the variations of the law with refer- ence to the moon's declination for any given period of the year, con- sists chiefly in the difference of the relative values of the maxima and minima, the differences of epochs being small. Thus for perihelion, the moon furthest north, the principal maximum occurs at the infe- rior passage ; the moon on the equator going south, the two maxima are nearly equal ; the moon furthest south, the maximum at the superior passage is by far the greatest : on the equator going north, the two maxima are again nearly equal ; and so on for other epochs. 10th. The moon's action is chiefly, if not wholly, dependent on the position of the sun, or (which is the same thing) on the position of the earth relatively to the sun ; and the law of the lunar action at the magnetic equator resembles in some points that for the solar action at the same epochs. Thus about aphelion there is a minimum of easterly (maximum of westerly) declination produced by the lunar action, as well as by the solar action, for these two bodies near the superior meridian; whereas about perihelion both actions for the sun and moon near the superior meridian produce maxima of easterly declination. A like analogy holds for near the epochs of sun- rise and moonrise. III. Postscript to a Paper " On Compound Colours, and on the Relations of the Colours of the Spectrum." By J. CLERK MAXWELL, Esq. Communicated by Professor STOKES, Sec. U.S. Received May 8, 1860. (Abstract.) Account of Experiments on the Spectrum as seen by the Colour-blind. The instrument used in these observations was similar to that already described. By reflecting the light back through the prisms by means of a concave mirror, the instrument is rendered much shorter and more portable, while the definition of the spectrum is 485 rather improved. The experiments were made by two colour-blind observers, one of whom, however, did not obtain sunlight at the time of observation. The other obtained results, both with cloud- light and sun-light, in the way already described. It appears from these observations — I. That any two colours of the spectrum, on opposite sides of the line " F," may be combined in such proportions as to form white. II. That all the colours on the more refrangible side of F appear to the colour-blind " blue," and all those on the less refrangible side appear to them of another colour, which they generally speak of as "yellow," though the green at E appears to them as good a repre- sentative of that colour as any other part of the spectrum. III. That the parts of the spectrum from A to E differ only in intensity, and not in colour ; the light being too faint for good experi- ments between A and D, but not distinguishable in colour from E reduced to the same intensity. The maximum is about f from D towards E. IV. Between E and F the colour appears to vary from the pure " yellow " of E to a " neutral tint " near F, which cannot be distin- guished from white when looked at steadily. V. At F the blue and the " yellow " element of colour are in equi- librium, and at this part of the spectrum the same blindness of the central spot of the eye is found in the colour-blind that has been already observed in the normal eye, so that the brightness of the spectrum appears decidedly less at F than on either side of that line ; and when a large portion of the retina is illuminated with the light of this part of the spectrum, the limlus luteus appears as a dark spot, moving with the movements of the eye. The observer has not yet been able to distinguish Haidinger's " brushes " while observing polarized light of this colour, in which they are very conspicuous to the author. VI. Between F and a point ^ from F towards G, the colour appears to vary from the neutral tint to pure blue, while the brightness in- creases, and reaches a maximum at •§ from F towards G, and then diminishes towards the more refrangible end of the spectrum, the purity of the colour being apparently the same throughout. VII. The theory of colour-blind vision being "dichromic" is con- firmed by these experiments, the results of which agree with those 486 obtained already by normal or " trichromic" eyes, if we suppose the "red" element of colour eliminated, and the "green5' and "blue" elements left as they were, so that the " red-making rays" though dimly visible to the dichromic eye, excite the sensation not of red but of green, or as they call it, " yellow." VIII. The extreme red ray of the spectrum appears to be a suf- ficiently good representative of the defective element in the colour- blind. When the ordinary eye receives this ray, it experiences the sensation of which the dichromic eye is incapable ; and when the di- chromic eye receives it, the luminous effect is probably of the same kind as that observed by Helmholtz in the ultra-violet part of the spectrum — a sensibility to light, without much appreciation of colour. A set of observations of coloured papers by the same dichromic observer was then compared with a set of observations of the same papers by the author, and it was found — 1 . That the colour-blind observations were consistent among them- selves, on the hypothesis of two elements of colour. 2. That the colour-blind observations were consistent with the author's observations, on the hypothesis that the two elements of colour in dichromic vision are identical with two of the three elements of colour in normal vision. 3. That the element of colour, by which the two types of vision differ, is a red, whose relations to vermilion, ultramarine, and emerald- green are expressed by the equation D=M98V + 0-078U-0-276G, where D is the defective element, and V, U and G the three colours named above. IV. " Report to the Royal Society of the Expedition into the Kingdom of Naples to investigate the circumstances of the Earthquake of the 16th December 1857." By ROBERT MALLET, Esq., C.E,, F.R.S. (Abstract.) The region examined in this expedition, embraces, in its widest extent, most of the country between a line drawn from Terracina to Gargano on the north, down to the Gulf of Taren turn on the south. 487 The earthquake, the greatest that has occurred in Italy since that of 1 783, was felt over nearly the whole of the Peninsula south of Terracina and Gargano. Its area of greatest destruction (the meizoseismal area), within which nearly all the towns were wholly demolished, was an oval whose major axis was in a direction N.W. and S.E. nearly, and ahout 25 geog. miles in length by 10 geog. miles in width. The first isoseismal area beyond this, within which buildings were everywhere more or less prostrated and people killed, is within an oval of about 60 geog. miles by 35 geog. miles ; the second isoseismal is also an oval within which buildings were everywhere fissured, but few prostrated and few or no lives lost. The third isoseismal embraces a greatly enlarged area, within which the earthquake was everywhere perceived by the unassisted senses, but did not produce injury. A fourth isoseismal was partially traced, within which the shock was capable of being perceived by instrumental means, and which probably reached beyond Rome to the northward. The author divides his Report into three parts. In the first he has developed the methods of investigation which he pursued for the purpose of finding the directions of movement of the wave of shock at various points, and thence to determine — 1st. The point upon the earth's surface vertically over the centre of effort or focal point, whence the earthquake impulse was delivered; 2nd, the depth below the surface (or rather sea-level) of the focal point itself. The line passing through both these points he calls the seismic vertical. The author points out, that of the three elements of the earthquake-wave, viz. the velocity of transit, the velocity of the wave-particle (or wave itself), and the direction of motion at each point of the seismic area, the first alone in other instances has hitherto been attempted to be determined, the velocity of the wave and that of its transit being apparently confounded, and any attempt at direction confined to the apparent path on the surface. He then shows that every displaced object is in fact a seismometer, and that the displacement of regular bodies, such as buildings or their parts, may be made, by examination of their conditions after the shock, and the application of the principles of dynamics, to give precise information as to the true directions- in azimuth and angles of emer- gence at various points of the wave, and its velocity at those points. 488 The effects produced, which are mainly available for such deter- minations, he shows are divisible into four great classes : — 1st. Fis- sures or fractures produced in buildings, from whose direction, &c. that of the wave-path at the point may be discovered : under this head the author has minutely described and figured the forms and peculiarities of fractures produced in all classes of buildings in the region examined. The principles deduced being universally appli- cable, he has shown the choice and precautions, &c. as to those best fitted for seismic observation, and given formulae for the deduction of the wave-paths, i. e. the direction in which the wave movement at the point emerges. Velocity may also be determined from fissures ; but this is more accurately ascertained from, 2nd, the overthrow of bodies, such as columns, piers, walls, &c., either fractured at their bases or simply overturned. 3rd. Fractures at the base without sensible movement, or with oscillation within an observed arc short of overthrow. 4th. The displacement of bodies by throw or projection, such as vases, finials, balustrades, bells, coping-stones, tiling, &c. from elevated points, in which, where the vertical height fallen, and the horizontal range are observed, the velocity can be determined or the direction of the wave-path and the angle of emergence of the wave ; — in certain cases all of these classes of displacement may occur variously combined. All these resolve themselves into fracturing forces, the movements of compound pendulums, and those of pro- jectiles ; and in arranging the formulae for application, the author acknowledges the important assistance rendered him by his friend the Rev. S. Haughton, Professor of Geology in the University of Dublin. The author concludes the first part by a description of the cha- racteristics of the towns and cities, buildings, &c. in the region examined, of the physical features, the orographic and surface con- figuration, and the geological structure of the south of Italy as em- braced in his investigation. The second part embraces the application of these methods of investigation, and the complete detail of the observations made by the author in his journey from point to point, — the working out at many separate points of the directions of the wave-paths and angles of emergence and wave-velocities, — the explications of the numerous and frequently singular and at first apparently perplexing circum- stances, producing abrupt changes in the local intensity 'of seismic 489 effects observed, — the description generally of the places examined and phenomena observed, embracing many examples of fissures in earth or rock, falls of rock, landslips, changes of water-courses, &c., and the explanation of their conditions, — the observations con- tinually made to correct the magnetic decimation for the observa- tions of wave-path by compass, — the hypsometric determinations by the barometer of many points of elevation, — geological sections over certain parts of the country examined, — the time observations obtained for determination of transit velocity. The descriptions are illustrated by numerous sketches made by the author on the spot, by diagrams and topical maps, and by a large series of photographs, made under the author's instructions, by a photographer who followed in his track. In the appendices to this part the author has given translations of all the notices that appeared in the ' Giornale Reale ' (the only Neapolitan newspaper), of the events of the shock, with tables of the meteorology of Naples, from those of the Royal Marine Obser- vatory, for certain periods before, during and after the shock ; also returns of the population, area, damage, deaths and number of wounded persons in the shaken provinces. In the third and concluding part the author colligates all his facts, classifies them, and draws his conclusions and generalizations under the following heads : — a. The superficial position of the seismic vertical. This, the author shows from the independent and concurrent evidence of above 70 separate wave-paths, was close to the village of Caggiano, near the E. extremity of the valley of the Salaris ; the evidence being of a highly cumulative character, as the intersection of two wave- paths only is sufficient to determine this point. b. The depth of the focal point below the sea-level. This, the author shows, was about 5| geographical miles, «. e. the mean focal depth. c. The forms and areas of the meizoseismal and the several isoseismal curves. These have been laid down by the author upon three large maps, protracted from Zannoni's great map of the kingdom of the Two Sicilies, upon a scale of more than half an inch to the geographical mile. Of these, the map A shows the wave-paths as determined in 490 azimuth, and their close concurrence at the seismic vertical, the position of all the points of observation, and the axial lines of the great mountain ranges. The map B gives the physical features of the country, and the four first isoseismal curves ; distinguishing the injuries done to the numerous cities and towns, &c. by separate colours. Upon both maps the probable horizontal form of the focal cavity is marked, which coordinates with the existing lines of dis- location of the country in a remarkable manner. The map C gives the whole of the isoseismals for this earthquake, and compares them with the corresponding seismal curves (so far as these can be obtained from the narratives), for a number of the greatest earthquakes on record which have occurred in the Italian Peninsula, including that of 1783. d. The effects of the physical configuration of the surface and formations beneath, on the progress of the wave of shock, are dis- cussed, and the peculiar oval forms and the directions of the major axes accounted for. e. The effects are pointed out, of the form and position of the focal cavity in modifying the distance of transmission of the wave of given effort in different directions. f. Applies the results to showing the actual conformity of the isoseismal curves to the principles enunciated. g. Under this head the author explains the nature of the separate system of wave-paths for Naples City, and the surrounding district, which only received the shock by transmission of refracted and trans- versal waves passed through the Monte St. Angelo range of moun- tains, with entire change of direction. h. Colligates the facts ascertained as to the sounds heard with the shock at various points round the seismic vertical, and points out the remarkable relations that the prolongation of the sound more or less at different points bears to the direction in length and in depth of the focal cavity, and generally the causes of the diversity of sounds heard at various points around earthquake centres. *. Discusses and points out the nature and correspondence with the dynamic laws of wave motions, of the tremors that preceded and followed the great shock, and generally the causes inducing such in all earthquakes. k. Refers to the ascertained phenomena of reiterated or double 491 shock at certain places, and points out the combinations, having reference to surface configuration chiefly, producing such from a single central impulse. Under the section I, the whole of the preceding information is combined, to deduce the dimensions, form and subterraneous position of the focal cavity, which the author shows to have been a curved lamellar cavity or fissure of about 3 geographical miles in depth by 9 geographical miles in length, with an inclined vertical section, and a mean focal depth (or depth of its central point of surface) of 5J geographical miles below the sea. In section m are discussed, upon the data of hypogeal increment of temperature (as supposed to be ascertained from deep mines and arte- sian wells), the necessary temperature of the focal cavity, and the in- tensity of the force that acted within it to produce impulse, assuming that to have been due to steam at high tension, either suddenly developed or suddenly admitted into a fissure rapidly enlarged by rending. n. Deduces the amplitude of the wave and the work stored up in it on reaching the surface, and compares the former with the observed amplitudes. o. Deduces the velocity of transit of the wave of shock upon the surface, from the most trustworthy of the observations of time at various localities. These are found to correspond with considerable exactness, and give a transit rate of between 700 and 800 feet per second, as that at which the wave form was propagated from point to point, differing with change of formation by amounts stated. p. Deduces the velocity of the wave itself, i. e. that of the wave particle, which is shown to have been in round numbers between 13 and 14 feet per second (in the direction of the wave-path). A remarkable relation is pointed out between this velocity and that recorded for the earthquake of Eiobamba, the greatest whose effects have been observed. The height due to the velocity of this wave is to the altitude of Vesuvius as that due to the velocity recorded of the Riobamba wave is to the mean height of the volcanic shafts of the Andes, and more especially to the height of the volcanic vents nearest to Riobamba. The author points out that the direct altitude of a volcano is the true measure of the volcanic and seismic energy beneath it, and not its volume, which is a measure both of energy and time combined. 492 Under section g, he discusses the facts ascertained by him, as to the decay of the wave of shock in relation to superficial distance from the seismic vertical. The amplitude of the wave slowly and slightly increases, and its velocity decreases. The observations are not sufficient to admit of certain deduction as to what function of the distance the law of decay follows. The lowest velocity at nearly 30 miles from the seismic vertical was still about 1 1| feet per second. Under r, the author has discussed systematically the facts ascer- tained as to the local disturbing causes producing abrupt perturba- tions of the wave of shock, and shown that they are : — 1st. Retardation by great fissures or faults, or deep valleys of dis- location; the effects of these, at about Muro and Bella, amounting almost to sudden extinction of the wave. 2nd. Alternate cutting off and partial extinction by parallel chains of mountains, and the effects of multiplied anti- and syn- clinals. 3rd. Increment and reduplication, with or without change of wave-path, by local reflection from mountain masses. 4th. Effects of free-lying surfaces (flanks and extremities of mountain ranges) and nodal points, and production of intersecting secondary shocks, and sudden reductions of energy by entrance of the wave to greatly increased masses. 5th. Effects of formation (geological), of change from one to another, &c. 6th. Effects of position of towns and cities on plain and hill, rock or loose material. Towns on steep rock eminences, such as Saponara, are shown to have suffered from an extreme conjoint velocity, viz. that of the wave itself, and that of the hill-top, oscillating as an elastic pendulum. Of all these modifying conditions, external contour of surface, and more especially the forms and directions, &c. of mountain masses and deep fissures, are shown to be the most efficient. The value is shown of contoured maps, models, or other such means of directing the mind to the true figure of the country, in seismic researches. In the section $, the author arranges and discusses the facts observed by him, as to secondary effects produced by the earthquakes, under the heads of — 1. Earth fissures and landslips. These are in directions generally more or less transverse to the wave-paths, but conform to and are 493 determined by the dip or slope of the subjacent beds of rock. Earth fissures are never produced by the direct passsage of the wave of shock. They are a mere secondary result, and are no more than incipient landslips. 2. Rock shattering and falls. 3. Alterations of water- courses, muddying of springs, &c., all of which are shown to be due to the secondary effects of landslips into their beds, falls of partially loose rock therein producing ponding up and subsequent debacle. The total modifying effects on the earth's surface are shown to be insignificant. No great sea-wave accompanied this shock ; nor was such possible, the focal point being inland. The author examined with care more than 150 miles of sea-coast, as well as river-courses, for evidence of any permanent elevation of land having taken place concurrently with this earthquake, but found none. Earthquakes cannot produce elevations, although the latter have been known to have taken place about the same time as earthquakes and in the same region. t. Discusses the meteorological phenomena, both during the earth- quake or directly after it, and for a prolonged period before it. Some remarkable relations are pointed out between the disturbance of the annual rainfall previously and the occurrence of shocks. The physical conditions concerned in widely alleged unusual meteoric light, diffused over the central portion of the shaken region at the night of the shock, and of the occurrence of oppressive heat, &c., are discussed ; and under u, the premonitory and other effects on lower animals, of nausea in men, &c., are considered. v. Points out that the method of investigation pursued, enables deductions even now to be drawn from ancient fissures, &c., as to the focal centres of earthquakes occurring at very remote periods. In map D, the lines of loci of the focal points for the whole of the Italian peninsula are, as far as practicable, laid down, and their general connexion with the seismic bands of the Mediterranean Basin (as deduced from the British Association Earthquake Cata- logue, and its accompanying Seismological Map of the World) is pointed out ; and some general relations both of the unequal distri- bution of the points of greatest energy along these seismic bands, and of the unequal evolution of energy at the same points, in long 494 periods of time, to the common origin of volcanic and seismic force, and its nature, are pointed out. Some observations of a practical engineering character are added, as to the proper construction of houses, &c. in earthquake countries, by which the author is satisfied that the disastrous loss of life at intervals recurring might be avoided. In conclusion, the author returns thanks to various individuals for co-operation in the objects of his expedition, and most especially to his friends Dr. Robinson, Prof. Haughton, General Sabine, Sir Roderick Murchison, and Sir Charles Lyell. June 7, 1860. The Annual Meeting for the Election of Fellows was held this day. Sir BENJAMIN C. BRODIE, Bart., President, in the Chair. The Statutes relating to the Election of Fellows having been read, Sir Philip Egerton and Mr. Babbage were, with the consent of the Society, nominated Scrutineers to assist the Secretaries in examining the lists. The votes of the Fellows present having been collected, the Presi- dent announced that the following gentlemen were duly elected into the Society : — Frederick Augustus Abel, Esq. Thomas Baring, Esq. John Frederic Bateman, Esq. Edward Brown-Sequard, M.D. Richard Christopher Carrington, Esq. Francis Galton, Esq. Joseph Henry Gilbert, Esq. Sir William Jardine, Bart. Thomas Hewitt Kev, Esq. Joseph Lister, Esq. Rev. Robert Main, M.A. Robert William Mylne, Esq. Roundell Palmer, Esq., Q.C. John Thomas Quekett, Esq. Edward Smith, M.D. The Society then adjourned to Thursday, June 14. 495 June 14, 1860. General SABINE, R.A., Treasurer and Vice-President, in the Chair. Francis Galton, Esq., Joseph Henry Gilbert, Esq., Thomas Hewitt Key, Esq., Joseph Lister, Esq., The Rev. Robert Main, Robert Wil- liam Mylne, Esq., and Edward Smith, M.D., were admitted into the Society. The following communications were read : — I. " Notes of Researches on the Poly-Ammonias." — No. VIII. Action of Nitrous Acid upon Njtrophenylenediamine. By A. W. HOFMANN, LL.D., F.R.S. Received April 5, 1860. The experiments of Gottlieb have shown that dinitrophenylamine, when boiled with sulphide of ammonium, is converted into a remark- able base, crystallizing in crimson needles, generally known as nitra- zophenylamine, and for which, in accordance with the views I enter- tain regarding its constitution, I now propose the name Nitrophe- nylenediamine. I owe to the kindness of Dr. Vincent Hall a con- siderable quantity of this substance, which is not quite easily pro- cured. I have made a few experiments with this compound in the hope of obtaining some insight into its molecular constitution. If, bearing in mind the numerous analogies between the radicals ethyl and phenyl, we assume that the latter, by the loss of hydrogen, may be converted into a diatomic molecule, phenylene C6 H4, corresponding to ethylene, the existence of a group of bases corresponding to the ethylene-bases cannot be doubted. (C2 Ethylamine H J-N*. Ethylenediamine H Phenylamine H \ N. Phenylenediamine H J * H = l; O = 16; C = 12,&c. VOL. X. T'h 2 M With the last-named hody agrees in composition the compound known as semibenzidam, or azophenylamine, which Zinin obtained by exhausting the action of sulphide of ammonium on dinitro- benzol. Those chemists, however, who have had an opportunity of be- coming acquainted with the well-defined properties of ethylenedia- mine, will not be easily persuaded to consider the uncouth dinitro- benzol-product — sometimes appearing in brown flakes, sometimes as a yellow resin, rapidly turning green in contact with the air — as stand- ing to smooth phenylamine in a relation similar to that which obtains between ethylenediamine and ethylamine; we much more readily admit a relation of this description between phenylamine and Gott- lieb's crimson-coloured base, in which the clearly pronounced cha- racter of the former is still distinctly visible, although of necessity modified by the further substitution which has taken place in the radical. Phenylamine Phenylenediamine Nitrophenylenediamine CeHJN. H/ 'X IN,. Hf " "•••--^i, i 2 J (C.[H,(NO,)])"1 H2 ? N2 H0 J Does the latter formula really represent the molecular constitution of the crimson needles ? The degree of substitution of this body might have been determined by the frequently adopted process of ethylation. But even a simpler and a shorter method appeared to present itself in the beautiful mode of substituting nitrogen in the place of hydrogen, lately discovered by P. Griess. The red crystals undergo, indeed, the transformation, which he has already proved for so many derivatives of ammonia, with the greatest facility. On passing a current of nitrous acid into a moderately concen- trated solution of the nitrate of the base, the liquid becomes slightly warm, and deposits on cooling a considerable quantity of brilliant white needles, the purification of which presents no difficulty : spa- 497 ringly soluble in cold, readily soluble in boiling water, the new com- pound requires only to be once or twice recrystallized. Thus puri- fied, this substance forms long prismatic crystals, frequently inter- laced, white as long as they are in the solution, but assuming a slightly yellowish tint when dried, and especially when exposed to 1 00° : they are readily soluble both in alcohol and in ether. The new body exhibits a distinctly acid reaction ; it dissolves on applica- tion of a gentle heat in potassa and in ammonia, without, however, neutralizing the alkaline character of these liquids ; it also dissolves in the alkaline carbonates, but without expelling their carbonic acid. The new acid fuses at 211° C., and sublimes at a somewhat higher temperature, with partial decomposition. The sublimate consists of small prismatic crystals. Analysis proves this substance to contain CeH4N402> a formula which is confirmed by the analysis of a silver-compound, C6(H3Ag)N402) and of a potassium-salt, C0(H3K)N402. The analysis of the new compound shows that, under the influence of nitrous acid, nitrophenylenediamine exchanges three molecules of hydrogen for one molecule of nitrogen, three molecules of water being eliminated. Nitrophenylene- New acid. diamine. I do not propose a name for the new compound, which can claim but a passing interest, as throwing, by its formation, some light on the constitution of nitrophenylenediamine. The composition of the new acid, and of its salts, shows that in the crimson-red base four hydrogen molecules are still capable of re- placement ; in other words, that this body contains four extra-radical molecules of hydrogen. The result of these experiments appears to confirm the view which, in the commencement of this Note, I have taken of the constitution of this body ; at all events, the mutual relation of the several bodies is satisfactorily illustrated by the formulae — 498 (C6[Ha(N02)])" Nitrophenylenediamine J8(N02)])"-l H2 >N2. H, J (C,[H8(N02)])'n New acid N'" ?N2. H J (C,[H3(N02)])" Silver-salt N'" Ag If the admissibility of this interpretation be confirmed by further experiments, the reaction discovered by Griess furnishes a new and valuable method of recognizing the degree of substitution in the derivatives of ammonia, The new acid differs in many respects from the substances pro- duced from other nitrogenous compounds. As a class, these sub- stances are remarkable for the facility with which they are changed under the influence of acids, and more especially of bases. The new acid exhibits remarkable stability; it may be boiled with either potassa or hydrochloric acid without undergoing the slightest change. Even a current of nitrous acid passed into the aqueous or alcoholic solution is without the least effect. The latter experiment appeared of some interest ; for if the action of nitrous acid, in a second phase of the process, had assumed the form so frequently observed by Piria and others, it might have led to the formation of the diatomic nitro- phenylene-alcohol, according to the equation (C. [H, (N02)])" 1 (C. [H3 (N02)])» 1 0 H2 JN2+2HN02=2H20 + N1+ H2 / l It deserves to be noticed that nitrophenylenediamine, although derived from two molecules of ammonia, is nevertheless a decidedly monacid base. Gottlieb's analyses of the chloride, nitrate, and sul- phate left scarcely a doubt on this point. However, as some of the natural bases, quinine for instance, are capable of combining with either one or two molecules of acid, I thought it of sufficient interest to confirm Gottlieb's observations by some additional experiments. The crystals deposited on cooling from a solution of nitrophenylene- diamine in concentrated hydrochloric acid, were washed with the same liquid and dried in vacuo over lime. 499 Analysis led to the formula The dilute solution of this chloride is not precipitated by dichlo- ride of platinum, nor can the double salt of the two chlorides be obtained by evaporating the mixed solutions, which, just as Gott- lieb observed it, is readily decomposed with separation of metallic platinum. I had, however, no difficulty in preparing a platinum salt, crystallizing in splendid long brown-red prisms, by adding the dichlo- ride of platinum to the concentrated solution of the hydrochlorate. The platinum determination led to the formula r ( LH{ (C.CH.CNO,)])'' ~, PtCL. These experiments prove that, even under the most favourable cir- cumstances, nitrophenylenediamine combines only with 1 equiv. of acid, while the ethylene-derivatives are decidedly diacid. The dimi- nution of saturating power in nitrophenylenediamine, at the first glance, seems somewhat anomalous, but the anomaly disappears if the constitution of the body be more accurately examined. It can- not be doubted that the diminution of the saturating power is due to the substitution which has taken place in the radical of the diamine. I have pointed out at an earlier period *, that the basic character of phenylamine is considerably modified by successive changes intro- duced into the phenyl-radical by substitution. Chlorphenylamine, though less basic than the normal compound, still forms well-defined salts with the acids ; the salts of dichlorphenylamine, on the other hand, are so feeble, that, under the influence of boiling water, they are split into their constituents ; in trichlorphenylamine, lastly, all basic characters have entirely disappeared. Again, on examining the nitro-substitutes of phenylamine, we find that even nitrophenylamine is an exceedingly weak base, whilst dinitrophenylamine is perfectly indifferent. What wonder, then, that a molecular system, to which in the normal condition we attribute a diacid character, should, by the insertion of special radicals, be reduced to monoacidity ? The normal phenylenediamine, which remains to be discovered, will doubt- * Mem. of Chem. Soc. vol. ii. p. 298. 500 less be found to be diacid, like the diamiues derived from ethylene. Even now the group of diacid diamines is represented in the naphtyl series : Naphtylamine V N monoacid. H (C10 H6)" 1 Naphtylenediamine H2 I N diacid. H, J The body which I designate by the term Naphtylenediamine, is the base which Zinin obtained by the final action of sulphide of ammo- nium upon dinitronaphtaline. This substance, originally designated seminaphtalidam, and subsequently described as naphtalidine, com- bines, according to Zinin's experiments, with 2 equivalents of hydro- chloric acid*. II. "On the Formula investigated by Dr. BRINKLEY for the general Term in the Development of LAGRANGE'S Ex- pression for the Summation of Series and 'for successive Integration." By Sir J. F. W. HERSCHEL, Bart., F.R.S. &c. Received April 26, 1860. (Abstract.) In the Philosophical Transactions for the year 1807, Dr. Brinkley has investigated an expression of the general term of the series of Lagrange and Laplace for the finite differences and integrals of any function u in terms of its differential coefficients and common inte- grals of successive orders ad infinitum, which is in effect equivalent to the development of the functions (e*— l)n and (ef— I )~n in powers of t. The demonstration of the formulae arrived at, as there stated, is circuitous and extremely difficult to follow ; so much so as to ren- der a simpler and easier one a desideratum in analysis, as there are probably few who have had the patience to follow it out to its con- clusion. More recently (Philosophical Transactions, 1816), the author of the present paper arrived at a general and extremely simple expression * Licbig's Annalen, vol. Ixxxv. p. 328. 501 for the coefficient of tn in the development of any function of el such as/{y), in which are included, as particular cases, the two functions treated in Dr. Brinkley's paper. In the case of (e*— 1)*, n being positive, the development so obtained agreed in form with that arrived at by Brinkley, and before him by Professor Ivory ; but in that of (ef— l)~n it differs from Brinkley's totally in point of form (though affording, of course, the same numerical results), being much simpler in expression and far more easily reduced to num- bers, Neither was it at all apparent by what mode of transforma- tion it was possible to pass from one form to the other ; and this has ever since remained a difficulty. The essential difference between the two forms is, that in the gene- ral coefficient, as expressed by Brinkley, the progression of terms of which it consists are multiplied respectively by the successive differ- ences of zero, A30*+3, &c., which run out in a diverging progression to infinity ; so that the number of terms of which the coefficient consists is limited, not by this progression coming to an end per sc, but by relations of another kind ; whereas in the coefficient resulting from the other mode of treatment, the differences of zero involved form the progression AO*, AV, ..... A*0*, which terminates per se at its #th term. A theorem subsequently demonstrated by the author of this paper, however, in his " Collec- tion of Examples in the Calculus of Finite Differences," affords the means of expressing any term in the former progression by a series of terms belonging to the latter. By substituting, then, the values so obtained for each of those which occur in Brinkley's series, the transformation in question is accomplished ; and the process, which has the appearance of considerable complexity, is singularly simpli- fied by the self-annihilation of all its most unmanageable terms. 502 III. « On the Thermal Effects of Fluids in Motion/' By J. P. JOULE, LL.D., F.R.S., and Professor W. THOMSON, LL.D., F.R.S. Received May 9, 1860. In our paper published in the Philosophical Transactions for 1854, we. explained the object of our experiments to ascertain the differ- ence of temperature between the high- and low-pressure sides of a porous plug through which elastic fluids were forced. Our experi- ments were then limited to air and carbonic acid. With new appa- ratus, obtained by an allotment from the Government grant, we have been able to determine the thermal effect with various other elastic fluids. The following is a brief summary of our principal results at a low temperature (about 7° Cent.) . Elastic fluid. Thermal effect per 100 Ibs. pressure on the square inch, in degrees Centigrade. 3-9 Air 7-9 Air 5-1 Air 3-5 Air 58-3 Air 62-5 Air 54-6 Nitre 4«23 Air Air. + 96-1 Hydrogen + 92*1 Nitrogen 1-6 Cold. 0-116 Heat. 1-772 Cold. 1-936 Cold. 8-19 Cold. 0-7 Cold. 3-486 Cold. 1-696 Cold. 2-848 Cold. + 94-9 Oxygen . . + 96 '5 Carbonic acid .. + 41-7 Hydrogen .... +3 7' 5 Carbonic acid . . gen +45*4 Oxvgen f +46-47 Hydrogen .. \ \ +49'3 Carbonic acid J Further experiments are being made at high temperatures, which show, in the gases in which a cooling effect is found, a decrease of this effect, and an increase of the heating effect in hydrogen. The results at present arrived at indicate invariably that a mixture of gases gives a smaller cooling effect than that deduced from the average of the effects of the pure gases. 503 IV. " On the Nature of the Light emitted by heated Tourma- line." By BALFOUR STEWART, Esq., M.A. Communicated by J. P. GASSIOT, Esq. Received May 22, 1860. Some months ago I had the honour of submitting to the Royal Society a paper on the light radiated by heated bodies, in which it was endeavoured to explain the facts recorded by an extension of the theory of exchanges. Having mentioned the difficulty which I had in maintaining the various transparent substances at a nearly steady red heat for a sufficient length of time in experiments demanding a dark back- ground, Professor Stokes suggested an apparatus by means of which this difficulty might be overcome ; and it is owing to his kindness in doing so that I have been enabled to lay these results before the Society. The apparatus consists of a thick, spherical, cast-iron bomb, about 5 inches in external and 3 inches in internal diameter — the thickness of the shell being therefore 1 inch. It has a cover removeable at pleasure. There is a small stand in the inside, upon which the sub- stance under examination is placed, and when so placed it is pre- cisely at the centre of the bomb. Two small round holes, opposite to one another, viz. at the two extremities of a diameter, are bored in the substance of the shell. If, therefore, the substance placed upon the stand be transparent, and have parallel surfaces, by placing these surfaces so as to front the holes, we are enabled to see through the substance, and consequently through the bomb. Let the bomb with the substance on the stand be heated to a good red heat, and then withdrawn from the fire and allowed to cool. It is evident that the cooling of the substance on the stand will proceed very slowly, as it is almost completely surrounded with a red-hot enclosure. It is also evident that, by placing the bomb in a dark room, we may view the transparent substance against a dark background. By this method of experimenting, therefore, the difficulty above alluded to is over- come. Before describing the experiment performed on tourmaline, it may be well to state what result the theory of exchanges would lead us to expect when this mineral is healed, and we shall perceive at the same 504 time the importance of the experiment with tourmaline as a test of the theory. When a suitable piece of tourmaline, with its faces cut parallel to the axis, is used to transmit ordinary light, the light which it transmits is nearly completely polarized, the plane of polarization depending on the position of the axis. The reason of this is, that if we resolve the incident light into two portions, one of which consists of light polarized in a plane perpendicular to the axis of the crystal, and the other of light polarized in a plane parallel to the same axis, nearly all the latter is absorbed, while a notable proportion of the former is allowed to pass. Suppose now that such a piece of tourmaline is placed in a red-hot enclosure ; the theory of exchanges, when fully carried out, demands that the light transmitted by the tourmaline, say in a direction per- pendicular to its surface, plus the light radiated by the tourmaline in that direction, plus the small quantity of light reflected by the surface of the tourmaline in that direction, shall together equal in quantity and quality that which would have proceeded in the same direction from the wall of the enclosure alone, supposing the tour- maline to have been removed. Let us neglect the small quantity of light which is reflected from the surface of the tourmaline, and, standing in front of it, analyse with our polariscope the light which proceeds from it. This light consists of two portions, the trans- mitted and the radiated, both of which together ought to be equal in quality and intensity to that which would reach our polariscope from the enclosure alone were the tourmaline taken away. But the light which would fall on our polariscope from the enclosure alone would not be polarized ; hence the whole body of light which falls upon it from the tourmaline, and which is similar in quality to the former, ought not to be polarized. Now part of this light, or that which is transmitted by the tourmaline, is polarized ; hence it fol- lows, in order that the whole be without polarization, that the light which is radiated should be partially polarized in a direction at right angles to that which is transmitted. Another way of stating this conclusion is this. The light which the tourmaline radiates is equal to that which it absorbs, and this equality holds separately for light polarized in a plane parallel to the axis of the crystal, and for light polarized in a plane perpendicular to the same. 505 The experiment was made with a piece of brown tourmaline having a few opake streaks, procured from Mr. Darker of Lambeth. It was placed in a graphite frame between two circular holes made as above described in opposite sides of the bomb, the diameter of the holes being about -^yths of an inch. On looking in at one of these holes you could thus see through the tourmaline and the opposite hole, or, in other words, see'quite through the bomb. An arrange- ment was also made by which part of the tourmaline might be viewed with the graphite behind it. The apparatus thus prepared was heated to a red or yellow heat in the fire, placed on a brick in a dark room, and the tourmaline viewed by a polariscope which Mr. Gassiot kindly lent me. The following was the appearance of the experiment : — Without the polariscope the transparent parts of the tourmaline were slightly less radiant than the field around them. When the polariscope was used, the light from the transparent portions of the tourmaline was found to vary in intensity as the instrument was turned round. No change of intensity could be observed in the light radiated by the opake streaks of the tourmaline, or by the graphite. The light from the transparent portions was therefore partially polarized. The polariscope was then brought to its darkest position, and a light from behind allowed to pass through the tourmaline. The light was distinctly visible in this position, but by turning round the polariscope about 90° it became eclipsed. The mean of four sets of experiments made the difference between the position of dark- ness for the two cases 88 1°. It appears, therefore, that the light radiated by the tourmaline was partially polarized in a plane at right angles to that which was transmitted by it. It was also ascertained that the light from the tourmaline which had the graphite behind it gave no trace of polarization. 506 V. " Researches on the Foraminifera." — Fourth and concluding Series. By W. B. CARPENTER, M.D., F.R.S., F.G.S., F.L.S. &c. Received June 14, 1860. (Abstract.) The author in this communication brings to a conclusion that series of inquiries into the structural and physiological characters of typical forms of Foraminifera, which he had been induced to work out for the sake of turning to the account of Zoological science the valuable collections made by Mr. Jukes in the Australian Seas and by Mr. Cuming in the Philippine. The first genus now treated of is Polystomella, the smaller and simpler forms of which have long been known, and of which the structure, so far as it can be elucidated by the examination of such specimens, has been already described with great care and accuracy by Professor W. C. Williamson. But in the comparatively gigantic and highly developed Polystomella of the Australian and Philippine series, a feature exists which is scarcely discernible in the humbler forms previously examined — that feature being the extraordinary development of the canal-system. A spiral canal runs along the inner margin of either surface of every whorl; from this canal a series of arches is given off, of which one passes down between every two adjacent segments, uniting it with the other spiral canal ; whilst another set of straight branches passes directly towards the surface of the shell, through the thick calcareous deposit which covers in the depressed centre of the spire, and which extends as far as the last- formed spire. From the connecting arches, successive pairs of diverg- ing branches proceed at frequent intervals ; these, in the last whorl, make their way to the surface of the shell, and (when the shell is newly formed) open close on either side of the septal band ; though, as the shell increases in thickness by subsequent deposit, the increased divergence of the branches separates their mouths from each other ; and it very commonly happens that the two contiguous branches diverging from different arches meet and open by a single external pore half-way between the septal bands. When one whorl, however, has been surrounded by another, this radiating canal-system of the inner whorl does not usually continue itself directly into that of the outer (though such a continuation is not unfrcquently seen), but 507 the diverging canals for the most part terminate in the stolons of communication between the segments of sarcode that occupy the chambers of the outer whorl. The evidence afforded by the distribution of the canal-system in Polystomella is decidedly confirmatory of the view expressed by the author on a former occasion, that this peculiar set of inosculating passages is related to the formation and nutrition of those solid calcareous layers which strengthen and connect the proper walls of the chambers, and to which he has given the designation of the " intermediate skeleton." This view derives strong confirmation from the still more extensive distribution and greater importance of the canal-system of Calcarina, a genus of which Mr. Cuming's Philippine collection affords a most remarkable series of illustrations. This type may be considered as closely allied to Polystomella in the disposition and mode of com- munication of its chambers, save that the spire is generally more or less inequilateral. Its "intermediate skeleton" is, however, much more developed ; and it extends itself into a variable number of pro- longations, sometimes simply club-shaped, sometimes more or less ramifying, which radiate in different directions from the central body, giving it somewhat the appearance of a spur-rowel, whence its generic designation. (An approach to this configuration is occasion- ally presented by the common Polystomella crispa, as also by some other species of Polystomella.) Now the independence of the intermediate skeleton and of the spiral system of chambers is curi- ously shown by the disproportionate development which they respect- ively exhibit the one to the other, and by their occasional complete disconnexion, — the spire altogether departing from its usual course, and (as it were) running wild, whilst the intermediate skeleton with its prolongations still present their ordinary configuration. The nutrition of the intermediate skeleton seems to be provided for by a system of large canals, freely inosculating with each other, which originate on the sides of the chambers, and are continued through the whole thickness of the intermediate skeleton, some of them pass- ing directly to its nearest surface, whilst others are continued to the terminations of its radiating prolongations. It is not a little remarkable that a Foraminiferous organism should present itself so extremely resembling the preceding as to be easily 508 mistaken for it, and yet essentially differing from it in its plan of structure. This is the case with a type of which some remarkable specimens occur in Mr. Cuming's collection, and of which some smaller examples have been kindly put into the author's hands by Dr. J. E. Gray. As it seems to be identical with the body described by Montfort under the designation Tinoporus baculatus, it may be right to retain that name, although it had been abandoned under the impression that it was a mere synonym of Calcarina. The structure of this body will be better understood after the description of a simpler form, which seems to be generally diffused through the seas of warmer latitudes, but of which the most remarkable examples present themselves in Mr. Jukes's Australian dredgings. Its shape is extremely variable, being sometimes an almost perfect sphere, in other cases resembling the lower half of a sugar-loaf, whilst in other cases again it is a very irregular depressed cone. It seems originally to have grown attached to zoophytes, corals, &c., since it frequently presents indications of such former attachment, though it is rarely to be met with otherwise than free. It is, moreover, very closely allied in structure to the body which has been termed Polytrema miniaceum, under the belief that it was a Polyzoan Coral, but whose Foraminiferous affinities have been already perceived by Dr. Gray, who has proposed for it the generic name of Pustulipora. In the commencement of its growth, this organism seems closely to resemble Planorbulina, being formed of an assemblage of cham- bers arranged on one plane, spirally towards the centre, but irregularly clustered towards the circumference ; each chamber communicating by single large septal orifices with the two contiguous chambers of the same row, whilst its walls are perforated with numerous large pseudopodian foramina. This first-formed plane, however, is after- wards covered-in above and below by numerous successive layers of similar cells, which are piled one upon another in very regular rows ; the original spiral type of growth being altogether lost in these super- posed layers. In this mode the organism comes to present a near relationship to the fossil genus Orbitoides* ; the principal difference being that the superposed layers are not so completely differentiated from the original median layer in Tinoporus as they are in Orbitoides. * See the author's account of the structure of that genus in the Quarterly Journal of the Geological Society, vol. vi. 1850, p. 32. 509 Now in Tinoporus baculatus we often find columns of solid shell- substance interposed between the angular partitions of the piles of superposed cells, just as they are in Orbitoides, their summits being visible on the surface as projecting tubercles ; these columns are perforated with pseudopodian canals, which are extensions of the pores in the walls of the chambers over which they lie. And the peculiar stellate projections which give to this species so much the aspect of a Calcarina are for the most part formed of a similar growth ; for though the chambered structure is continued for a short distance as a conical protuberance into the base of each, yet this cone is invested and extended by a sheath of solid shell-substance, which is perforated by pseudopodian tubes extending through it from the chambers. The last type of Foraininiferous structure described in this com- munication is one which appears to furnish a highly interesting link of connexion between Foraminifera and Sponges. Its nature was at first entirely misunderstood ; the specimens in Mr. Cuming's collec- tion having been supposed, not only by Mr. Cuming, but by other con- chologists, to be shells of a sessile Cirripede. Their external resem- blance might readily justify such an inference ; since they are irre- gular cones, apparently composed of distinct valves, attached by a spreading base to the surface of shells or corals, and having a single orifice at their apex. A careful examination of the interior structure, however, makes it evident that the shell is multilocular, and that it is formed upon the type of the Helicostegue Foraminifera, closely resembling Globigerina in the commencement of its growth ; the supposed ' valves ' being the walls of the outer whorl, the chambers of which are very large, and are partially subdivided by incomplete septa. All the principal chambers communicate by orifices of their own with a sort of central funnel which leads to the external orifice ; and thus their relation to it is very much that of the separate orifices of the chambers of Globigerina to its umbilicus. The cavities of the chambers are occupied by a spongeous tissue, which contains sili- ceous spicules ; and although the possibility that this spongy sub- stance may be parasitic must not be lost sight of, yet reasons are given which seem to render it almost certain that this is the proper body of the organism, on which Dr. Gray, who first discerned its true affinities, has conferred the generic name of Carpenteria. The author concludes with some general observations upon the 510 mutual affinities of the " typical forms " of Foraminifera whose struc- ture he has now elucidated ; and he sums up the evidence which his examination of them has furnished in regard to the very wide range of variation which seems especially to characterize this group, — avowing his conviction that the only classification of it which can approach to a really natural arrangement, will be one founded upon the idea of " descent with modification " as the means by which an almost infinite variety of special forms has been evolved from a few fundamental types. June 21, 1860. Sir BENJAMIN C. BRODIE, Bart., President, in the Chair. Frederick Augustus Abel, Esq., Thomas Baring, Esq., John Frederic Bateman, Esq., Edward Brown-Sequard, M.D., Richard Christopher Carrington, Esq., and Roundell Palmer, Esq., were admitted into the Society. In accordance with notice given at the last Meeting, the Right Honourable George Augustus, Earl of Sheffield, was proposed for election and immediate ballot ; and the ballot having been taken, his Lordship was declared duly elected. The following communications were read : — I. " Experimental Researches on various questions concerning Sensibility." By E. BROWN-SEQUARD, M.D. Communi- cated by Dr. SHARPEY, Sec. R.S. Received May 24, 1860. The first question I propose to examine relates to the duration of sensibility in parts of the body completely deprived of the circu- lation of blood. This question has hitherto received but little attention from phy- siologists. It is true that many experiments have been made to ascer- tain how long sensibility remains in animals in which circulation is stopped by the application of a ligature round the large blood-vessels of the heart ; but I do not know of any special research upon the duration of sensibility in a nerve in which there is a suspension of 511 circulation. No doubt it has been occasionally observed, iu experiments made with the view of ascertaining what effects are due to the ligature of the aorta, that sensibility persists in the nerves of the lower limbs much longer than irritability in the muscles, but no precise determi- nation has been made of the exact duration of sensibility in such cases, except, to a certain extent, in some experiments of my own and those of Stannius. My researches, although giving an indication of the duration of sensibility in the lower limbs, had not been made with the special view of elucidating this question, their object being to decide whether the vital properties of muscles and nerves could be restored after having completely disappeared. The experiments of Stannius were made with the same view as mine. It may therefore be said that the subject of the present paper is almost entirely new, at least as regards warm-blooded animals. A ligature round the aorta does not stop circulation completely enough to allow any positive conclusion regarding the duration of sensibility in nerves deprived of circulation of blood. Desirous of avoiding the causes of error which exist when the aorta is tied, I have proceeded in the following manner : — I apply ligatures on the femoral artery, and after having divided this vessel between the ligatures, I amputate the thigh completely, excepting, however, that I leave the two large nerves of the limb undivided and as little injured as possible. In experimenting in this way, I find — 1st. That the duration of sensibility in the toes, in Rabbits, varies between twenty and twenty -three minutes. 2nd. That, in Guinea-pigs, the duration varies between forty and fifty minutes. I have seen sensibility lasting a little more than an hour in one case. 3rd. That, in Dogs, the duration of sensibility varies between thirty and thirty-five minutes. It is a very remarkable fact that the duration of sensibility varies so much in animals so nearly related to each other as Rabbits and Guinea-pigs. The second question I propose to examine relates to the influence of temperature on the duration of sensibility in parts deprived of the circulation of blood. It has been erroneously assumed that vital pro- perties last longer in parts submitted to a temperature similar to that VOL. x. 2 N 512 of the body, than in parts of which the temperature is very much lowered. I have experimented on almost completely amputated limbs of Guinea-pigs, as in the preceding instances. The limbs were placed in a vessel dipped into water at different temperatures. The results have been as follows : — 1st. Water at 104° Fahr. Duration of sensibility, in average forty-one minutes. 2nd. Water at 80° Fahr. Duration of sensibility forty-nine mi- nutes. 3rd. Water at 50° Fahr. Duration of sensibility fifty-three mi- nutes. 4th. Water at 35° Fahr. Duration of sensibility fifty-eight mi- nutes. These results, which will not surprise persons who know the laws of the influence of heat and cold on the vital properties of the spinal cord, of motor nerves and muscles, clearly show that the lower the temperature, the longer sensibility persists in parts deprived of circulation. The third question I have tried to solve, is whether an augmentation in the vital properties of the spinal cord is able to influence the duration of sensibility in a limb deprived of the circulation of blood. It is known that when a transverse section is made upon the poste- rior surface of the spinal cord in a mammal, and especially in a rabbit, all the parts of the body which are behind the section become much more sensitive than they were previous to the opera- tion. I have made two series of experiments to find out if, in cases of this kind, the duration of sensibility in parts deprived of circulation would be increased. In one series of experiments I first divide the posterior columns of the spinal cord and then amputate all the parts of a hind limb ex- cept the nerves, while in another series I divide the spinal cord after having made the amputation. In both series I find that sensibility lasts notably longer than in animals in which the posterior columns have not been divided. For instance, in rabbits, instead of twenty or twenty-two minutes, sensibility lasts thirty or thirty-five minutes ; and in one case I have seen it still persisting, though very weak, after thirty-eight minutes ; I did not in this instance ascertain how long it lasted. 513 A very remarkable fact is that in a rabbit in which the spinal cord is in a normal condition, and in which the toes, after partial amputation as in the preceding experiments, are about losing the last appearance of sensibility, I find that there is a rapid and very notable return of this vital property if I divide the posterior columns of the spinal cord in the dorsal region. These experiments show that when sensibility seems to be lost in a part deprived of circulation , it is not completely so, but that the transmitted excita- tion which causes sensation is too slight to produce it, and that if in its way to the sensorium this excitation meets with a cause of increase, then sensation can be produced by it. II. " On Quaternary Cubics." By the Rev. GEORGE SALMON. Communicated by ARTHUR CAYLEY, Esq. Received June 14, 1860. (Abstract.) In this paper quaternary cubics are discussed under the canonical form first given by Professor Sylvester, where The writer shows how, when quantics are thus expressed with a supernumerary variable, it is possible to form contravariants also expressed with a supernumerary variable, and such that for the vari- ables, either in covariant or contravariant, we may substitute differ- entials with regard to the variables of the other. By the help of this principle, covariants, contravariants, and invariants of the cubic are formed with great facility. It is proved that a quaternary cubic has five fundamental invariants of the degrees respectively 8, 1 6, 24, 32, 40, as well as an invariant of the degree 100, whose square can be expressed in terms of the five fundamental invariants. The discri- minant is also expressed in terms of the four first of these in variants. It is remarked that in the same manner as the theory of ternary cubics is analogous to the theory of binary quartics, so there are many analogies between the theory of quaternary cubics and that of binary quintics. Four covariants are noticed of the first degree in the variables, by the aid of which expressions for the cubic can be obtained analogous 2N2 514 to what M. Hermite has called the "four types" of binary quintics. Other covariants of the cubic are discussed, and in particular a general expression is given for that covariant of the 9th order which geometrically represents a surface passing through the twenty-seven right lines on the surface of the third order represented by the cubic. III. " On the Construction of a new Calorimeter for determining the Radiating Powers of Surfaces, and its application to the Surfaces of various Mineral Substances." By W. HOPKINS, Esq., M.A., F.R.S., &c. Received June 1, 1860. (Abstract.) When the author's Memoir on the Conductivity of various sub- stances was presented to the Society, it was intimated to him on the part of the Council of the Society, that it might be advisable to de- termine absolute instead of relative conductivities, the latter only having been attempted in his previous experiments. It is partly in consequence of this intimation, and partly from the desire to make his former investigations more complete, that the author has given his attention to the construction of a calorimeter which might serve for this purpose. His present memoir contains a description of this instrument, with the results obtained from its application to the surfaces of various substances. The apparatus used by Messrs. Dulong and Petit was more deli- cate and complete than the simpler instrument devised by the author of this paper, but it was calculated only to determine the radiating powers of substances of which the bulb of a thermometer could be constructed, or with which it could be delicately coated. The only substances to which, in fact, it was applied, were glass and silver, the radiation taking place, in the first case, from the naked bulb of the thermometer, and, in the second, from the same bulb coated with silver paper. In these cases, too, it was the whole heat radi- ating in a given time from the instrument, and not that which radiated from a given area, that was determined. For this latter purpose the apparatus was not well calculated, on account of the difficulty of ob- taining with accuracy the area of the surface from which radiation took place. The instrument here described can be easily applied to 515 any plane radiating surface, while the area of that surface can be easily determined to any required degree of accuracy. The quantity of heat radiating under given conditions, from a unit of surface in a unit of time, can thus be easily ascertained. The paper contains a detailed description of the instrument, and of the experiments made with it. The following are experimental results thus obtained, — the unit of heat being that quantity of heat which would raise 1000 grs. of distilled water 1° Centigrade. The formula is that of Dulong and Petit, where 0= temperature of the surrounding medium (the air in these ex- periments), expressed in Centigrade degrees ; t= the excess of the temperature of the radiating surface above that of the surrounding medium, in Centigrade degrees ; p= pressure of the surrounding medium (the atmosphere in these experiments), expressed by the height of the barometer in metres ; «== 1'0077, a numerical quantity which is always the same for all radiating surfaces and surrounding media. Then if Q denote the quantity of heat, expressed numerically, which radiates from a unit of surface (a square foot) in a unit of time (one minute), we have the following results for the substances specified : — Glass. / p Y45 233 Dry Chalk. Q= 8-613 fl»(«*- 1 ) + -03720 (-- 2 Dry New Red Sandstone. Q= 8-377 fl*(««-l) + -0372o(lL\ Sandstone (building stone). Q= 8-882 «e(a'— 1) + -03720(JP Polished Limestone. Q= 9-106 «V-1) + "03720 (JL Unpolished Limestone (same block as the last). 516 IV. " On Isoprene and Caoutchine." By C. GREVILLE WIL- LIAMS, Esq. Communicated by Professor STOKES, Sec. R.S. Received June 4, 1860. (Abstract.) This paper contains the results of the investigation of the two prin- cipal hydrocarbons produced by destructive distillation of caout- chouc and gutta percha. Isoprene. This substance is an exceedingly volatile hydrocarbon, boiling between 37° and 38° C. ; after repeated cohobations over sodium, it was distilled and analysed. The numbers obtained as the mean of five analyses were as follows : — Experiment. Calculation. Carbon . . . 88^0 '5") 60 88'2 Hydrogen . . 12-1 H8 8 11 '8 68 100-0 Three of the specimens were from caoutchouc and two from gutta percha. The vapour-density was found to be at 58° C. 2*40. Theory requires, for C10H8=4 volumes, 2'35. The density of the liquid was 0-6823 at 20° C. Action of Atmospheric Oxygen upon Isoprene. Isoprene, exposed to the air for some months, thickens and acquires powerful bleaching properties owing to the absorption of ozone. On distilling the ozonized liquid, a violent reaction takes place between the ozone and the hydrocarbon. All the unaltered hydrocarbon distils away, and the contents of the retort suddenly solidify to a pure, white, amorphous mass, yielding the annexed result on combustion : — Experiment. Calculation. Carbon 78-8 C10 60 Hydrogen . . 10-7 H8 8 Oxygen 10-5 0 8 76 100-00 This directly-formed oxide of a hydrocarbon is unique, as regards both its formula and mode of production. 517 Caoutchine. Himly's analysis was correct. The mean results of three analyses are compared in the following Table with those of M. Himly : — Mean. Himly. Calculation. >^^_ Carbon . . 88'1 88-44 C20 120 88'2 Hydrogen . 11-9 11'56 H16 16 11-8 136 100-0 Two of the determinations, the results of which are incorporated in the above mean, were made on a substance from gutta percha. The vapour- density was :»— Experiment. Himly. Calculation = 4 vols. 4-65 4-46 4-6986 We now for the first time see the relation between the two hydro- carbons. It is the same as between amylene and paramylene. The author discusses the boiling-point of these bodies, and shows that they form most decided exceptions to Kopp's empirical law. Action of Bromine on Caoutchine and its isomer Turpentine. Caoutchine and turpentine act on bromine in precisely the same manner. One equivalent of the hydrocarbon decolorizes four equi- valents of bromine. To determine this point quantitatively, eight experiments were made, four with turpentine and four with caout- chine. The quantity of bromine-water employed was 20 cub. cents. =0*2527 gramme bromine. Mean of four turpentine experiments. Mean of four caoutchine experiments. 0-1074 grm. 0-1091 grm. Conversion of Turpentine and Caoutchine into Cymole. By the alternate action of bromine and sodium on caoutchine or turpentine, two equivalents of hydrogen are removed, the final result being cymole, having exactly the odour hitherto considered charac- teristic of the hydrocarbon obtained from oil of cumin, and quite distinct from that of camphogene. The liquid was identified by the annexed analyses. No. I. was from turpentine, II. and III. from caoutchine. 518 Experiment. ^. A^_ Calculation. __,._ ^ _JA__ /•»• I. II. III. Mean. s*~ ' • s. Carbon . 89-2 89'5 89-5 89-4 C20 120 89'6 Hydrogen . . 10'5 10-4 10-4 10-4 Hu 14 10-4 Agreeing perfectly with the formula C20H14*. 134 100-0 Paracymole. At the same time that cymole is formed, there is a production of an oil having the same composition, but boiling about 300° C. The author has provisionally named it paracymole. Action of Sulphuric Acid on Caoutchine. Sulphuric acid acts on caoutchine, converting it almost entirely into a viscid fluid like heveene, at the same time a very small quantity of a conjugate acid is formed, having the formula C20HI6S2O6; the composition was determined from that of the lime salt, which on ignition, &c., gave a quantity of sulphate of lime equal to 8'3 per cent, of calcium ; C20 H15 Ca S2 O6 requires 8'5. The author considers the action of heat on caoutchouc to be merely the disruption of a polymeric body into substances having a simple relation to the parent hydrocarbon. He deduces this view from the similarity in composition between pure caoutchouc, isoprene, and caoutchine. The following Table contains the principal physical properties of isoprene and caoutchine : — Table of the Physical Properties of Isoprene and Caoutchine. Name. Formula. Boiling-point. Specific gravity. Vapour-density. Expt. Calculated. Isoprene Caoutchine C10H8 C20 H16 37° 171° 0-6823 at 20° 0-8420 2-44 4-65 2-349 4-699 In the calculations rendered necessary by the numerous vapour- * (Note received July 27.) Both the cymole from turpentine and that from caoutchine were converted into insolinic acid by bichromate of potash and sul- phuric acid. The quantitative determinations made on the silver salt of the acid were almost theoretically exact. 519 density determinations contained in this paper, and more especially in those " On some of the products of the Destructive Distillation of Boghead Coal," the author has so repeatedly had to ascertain the value of the expression - nrw^T' *^at ^e was m(*uced to calcu- 1 ~|~ U' late it once for all for each degree of the Centigrade thermometer from 1° to 150°. As it is always easy so to manipulate as to prevent the value of T falling between the whole numbers, the Table proved a most valuable means of saving time ; the author has therefore appended it to his paper in the hope of its proving equally useful to other work- ing chemists. V. "On the Thermal Effects of Fluids in Motion— Tempera- ture of Bodies moving in Air." By J. P. JOULE, LL.D., F.R.S., and Professor W. THOMSON, LL.D., F.R.S. Received June 21, 1860. (Abstract.) An abstract of a great part of the present paper has appeared in the * Proceedings/ vol. viii. p. 556. To the experiments then adduced a large number have since been added, which have been made by whirling thermometers and thermo-electric junctions in the air. The result shows that at high velocities the thermal effect is proportional to the square of the velocity, the rise of temperature of the whirled body being evidently that due to the communication of the velocity to a constantly renewed film of air. With very small velocities of bodies of large surface, the thermal effect was very greatly increased by that kind of fluid friction the effect of which on the motion of pendulums has been investigated by Professor Stokes. VI. " On the Distribution of Nerves to the Elementary Fibres of Striped Muscle." By LIONEL S. BEALE, M.B., F.R.S., Professor of Physiology and of General and Morbid Ana- tomy in King's College, London, and Physician to King's College Hospital. Received June 19, 1860. (Abstract.) After alluding to the general opinions entertained with respect to 520 the termination of nerve-fibres in voluntary muscle, and to Kiihne's recent observations, the author proceeds to state that his researches have led him to the conclusion that every elementary fibre is abun- dantly supplied with nerves, which form a network and lie upon the surface of the sarcolemma. They do not penetrate through this membrane. The nerves never terminate in points, neither can any elementary fibres, or any part of a muscle, be found to which nerves are not freely distributed. The nerves run for the most part with the smaller arteries, and come into very close relation with the capillary vessels. The ele- mentary fibres of the tongue and diaphragm of the white mouse are nearly covered with nerve-fibres and capillaries. Generally, the muscular fibres of mammalia and birds receive a much larger supply than those of reptiles and fishes. The muscular fibres of some in- sects appear to receive a most abundant supply. As the nerve-trunks approach their distribution the individual fibres divide and subdivide, as was demonstrated long ago by "Wagner. The fibres resulting from the subdivision often pursue a very long and complicated course by running parallel with other fibres derived from different trunks, until, after being traced for some distance, it is not possible to follow them. Fine trunks composed of from three to seven or eight fibres can often be seen traversing the muscle. The fibres pursue different directions ; some dip down between the elementary muscular fibres, some pass and form with others from a different source small compound trunks, while others may be traced onwards for some distance ; the individual fibres which gradually separate from each other being distributed to different parts, in suc- cession, of several elementary muscular fibres. When the finest nerve-fibres can be seen passing round the elementary muscular fibre, they clearly consist of very delicate flattened bands. Of the oval bodies or nuclei. — Connected with all nerves in every part of the body, sensitive, motor, vascular, and probably in all animals, are little oval bodies or nuclei, which are the organs by which the nerves are brought into the closest relation with other textures. The nerves multiply at their distribution by the division of these little bodies, and upon them their nutrition and the mani- festation of the nervous phenomena depend. A great number is associated with perfection of nervous actions, and v ice versd. They are found very freely connected with the vascular nerves, are abun- 521 dant on those nerves near the ganglia from which they proceed, and in the ganglia themselves. These bodies, with the nuclei of capillary vessels and those of fat vesicles, and probably other struc- tures with peculiar cells, which alone deserve the name, have been included under the term " areolar tissue corpuscles " (Bindegewebe- korperchen). As specimens are usually prepared, it is quite impos- sible to distinguish these structures from each other. It is pro- bable that the gelatinous fibres, or fibres of Remak, are after all real nerve-fibres, and not a peculiar modification of fibrous tissue, as is now generally believed. The nerves and vessels, and with them, of course, the oval bodies, may be stripped off from the elementary muscular fibre. They are in close contact with the sarcolemma; and the author has been led to conclude from some appearances he has observed, that this structure is really composed of capillaries and nerve-fibres, with intervening tissue. Of the manner in which nerves terminate. — The fibres connecting the oval bodies or nuclei form with them a network, the branches of which are of course continuous with the subdivisions of the nerve- fibres. The arrangement of the network, and especially the number and proximity of the nuclei to each other, differ materially in dif- ferent localities. On sentient surfaces the meshes are very small and the nuclei close together ; but from the complexity and great number of the fibres, from the fact that many fibres which appear to be single can be resolved into three or four individual fibres, and from the circumstance of the network being imbedded, in most cases, in the midst of fibrous tissue, it is very difficult to describe its exact relations and disposition. However, from the connexions of this network with the nerve-fibres, it would seem to follow that an im- pression made upon a given portion of a sentient surface might be transmitted to the nervous centre by contiguous fibres, as well as by the one which would form, so to say, the shortest route ; and it is possible that impulses to motion may be conveyed to muscular fibres by a more or less circuitous path, as well as by a direct one. Of the so-called tubular membrane. — This is a transparent struc- ture in which the nerve-fibres are imbedded. It cannot strictly be called a membrane, because in many cases several fibres are im- bedded in it, and often it is much thicker than the fibres it contains. 522 By examination with high powers (700 diameters), many fibres which appear to be single when seen by lower powers can be resolved into three or more, all enclosed in the same transparent tissue. As the nerve- fibres approach their distribution, this transparent structure becomes much spread out. It is intimately connected with nerve- fibres and capillaries, and with them forms a delicate expansion over the muscular fibres and in other parts ; delicate fibres also, in con- nexion with the nerves and capillaries, may be observed in it. In some cases this expansion seems to be incorporated with the sarco- lemma, and it is probable that in certain instances it is really the structure which has received that name. Axis cylinder and white substance. — The author has been led to conclude that, in consequence of the free division of the axis cylinder and white substance near the point of distribution of the nerve, a single fibre in the trunk of a nerve may carry impressions to or from a much larger extent of surface than is generally supposed. The white substance which surrounds the axis cylinder gradually dimi- nishes, until, in the finer ramifications, it is impossible to say that a fibre consists of an axis cylinder and white substance ; for its general appearance and refractive power are the same in every part, except where the nuclei are situated. The author considers that the defi- nite characters of the axis cylinder and white substance in the trunks of the nerve, may be due to the gradual growth and altered relations of the fibres which occur during the development of the entire or- ganism. In the ultimate ramifications the whole fibre seems to con- sist of a very transparent and perhaps delicately granular substance, but no tubular membrane, medullary sheath, or axis cylinder can be demonstrated as distinct structures. Of the formation of new fibres. — In connexion with the terminal ramifications, new fibres are being continually developed by the division of the nuclei, and old ones undergo removal. The remains of the latter may, however, be seen in the form of very delicate fibres, in connexion with active nerve-fibres. The author regards much of the so-called connective tissue between the elementary fibres of muscle and in some other situations, as of this nature, — as the remains of structures whose period of functional activity was past, and which have been removed, all but this small quantity of insoluble material. 523 The method of preparing the specimens is then briefly described. Observations were conducted principally on white mice, which were injected with the author's prussian blue fluid immediately after death *. The paper concludes with the following summary of the most important facts elucidated in the inquiry : — 1. That nerve-fibres in muscle and in many other tissues, if not in all, may be traced into, and are directly continuous with, a net- work formed of oval nuclei and intermediate fibres. 2. That the organs by which nerves are brought into relation with other textures, and the agents concerned in the development of nerves and the formation of new fibres, are the little oval bodies or nuclei which are present in considerable number in the terminal ramifications of all nerves. A great number of these bodies is asso- ciated with exalted nervous action, while, when they are sparingly found, we may infer that the nervous phenomena are only imperfectly manifested. 3. That every elementary fibre of striped muscle is abundantly supplied with nerves, and that the fibres of some muscles receive a much larger supply than others. 4. That the nerves lie, with the capillaries, external to, but in close contact with, the sarcolemma. They often cross the muscular fibre at right angles, so that one nerve-fibre may influence a great number of elementary muscular fibres. There is no evidence of their pene- trating into the interior of the fibre. The paper is illustrated with drawings, most of them magnified 700 diameters. VII. " On the Effects produced by Freezing on the Physiolo- gical Properties of Muscles/' By MICHAEL FOSTER, B.A., M.D. Lond. Communicated by Dr. SHARPEY, Sec. R.S. Received June 4, 1860. The influence of cold upon animal life has been studied chiefly (as for example in reference to the phenomena of hybernation) at such degrees of temperature only as are insufficient to freeze the tissues. In cases of actual freezing, attention seems for the most part to have * The Microscope in its Application to practical Medicine, p. 63. 524 been directed to the organism as a whole, with a view of determining the question whether an animal apparently frozen to death could be revived. The older writers* often allude to the revival of frozen insects as a familiar fact. Rudolphif states that frozen Filariae are brought to life upon thawing. Franklin found frozen fishes revive on thawing; yet John Hunter J never succeeded in restoring the animals he had frozen. One element of uncertainty in such experiments (in those on ver- tebrate animals at least) is the difficulty of making sure that the heart itself is frozen, without interfering with the expected result. In the experiments of a later observer, Dumeril §, it seems clear that the hearts of the frogs he froze and recovered, were not frozen, though the intestines were. Spallanzani || seems to have been the only one among the older writers who studied the freezing of muscles removed from the influ- ence of the general blood-current, and that only in an indirect way. He revived irritability in the muscles of frogs, toads, and sala- manders, which, after immersion for several hours in snow, had be- come rigid, "presque gelees," and gave no contraction upon being stimulated. But he states that muscles frozen by a more intense cold lost their irritability for ever. His means of stimulation were chiefly mechanical. There seems fair reason to suspect that the muscles which recovered their irritability were but partially frozen, had but partially lost their irritability, and would have exhibited a de- cided contraction when treated by those modifications of the galvanic stimulus which the modern physiologist has at his command. Spal- lanzani^]", in another work, states that frozen snails died. Among later writers, the only authority I can find is Schiff, who states**, "A sufficiently intense degree of cold will render muscles rigid, and yet so that they can be revived. It is not clearly made out though whether this is accompanied by any contraction." And again, p. 46, " Frogs' muscles bear freezing without irretrievable loss of irritability for a longer time than they will exposure to that * Reaumur, Whytt, Blumenbach, Spallanzani. f Histor. Entoz. t. ii. p. 62. J Works by Palmer, vol. iv. p. 131. § Annales des Sciences Naturelles, 1852, vol. xvii. p. 7. || Opuscules, tr. Senebier, vol. i. (ch. vi.) p. 113. ^ Letters on Respiration. ** Lehrb. s. 44. 525 degree of heat which resembles frost in depriving them of irrita- bility." Having myself made some experiments on this subject, I venture to lay them before the Society. Two methods were adopted to freeze the muscles. In most in- stances I securely enclosed them in little bags of thin gutta percha, and so buried them in a mixture of salt and snow, or pounded ice. At other times I suspended them in pure olive oil, contained in a small vessel surrounded by the freezing mixture ; having previously ascer- tained that immersion for two hours at least in the same oil, at an ordinary temperature, had no injurious effect upon muscular irrita- bility. The results I came to were as follows : — 1. Completely frozen muscles are not irritable to the strongest stimulus we possess. 2. Muscles which have been frozen for a short time only (five or ten minutes at the longest) may regain their irritability on being thawed. 3. Muscles which have been frozen for more than ten minutes never regain their irritability. The loss of irritability seems to be due more to the occurrence of freezing than to any mere fall of temperature. For although the irritability does diminish with the fall of temperature, and markedly so when the freezing-point of water is neared, yet the great loss and final extinction takes place only when the tissue itself is frozen. I know of no method of treating a muscle so as to lower the free- zing-point of the water contained in its tissue, without so injuring it as to render such a procedure useless for the present purpose. In order that the irritability of any muscle should wholly disap- pear, the muscle must be wholly frozen. A muscle may be in great part frozen, and yet capable of producing a movement when stimu- lated, by the contraction of the unfrozen part. The passage into the frozen state is accompanied by no contrac- tion. Frogs' limbs freeze exactly in the same position which they were previously maintaining ; and when the individual muscles were frozen singly, I was unable to satisfy myself of the occurrence of any contraction. Nor could I assure myself of the advent of any physio- 526 logical rigidity distinguishable from the physical frozen state. The reaction of frozen muscle, as indicated by litmus paper, is neutral or faintly alkaline, thus differing from recently dead muscles. It is not the mere rigidity of the frozen muscle which mechanically, so to speak, prevents contraction, for irritability does not at once and fully return upon thawing. An interval of time may with care be detected in most cases, during which the muscle is already thawed, but yet not irritable ; and irritability returns gradually. There is no exact relation between the duration of the frozen state and the duration and amount of the revived irritability. It is not the case that a muscle frozen three minutes regains twice as much irritability, or remains afterwards irritable twice as long as a muscle frozen for six minutes. The frost does not progressively exhaust as it were a given store, leaving, according as the operation is shorter or longer, more or less residue to be manifested when the muscle is thawed. The amount of revived irritability will depend in great measure on the treatment the muscles experience when first thawed. The receipt then of a slight shock, which afterwards it will bear with im- punity, if not with advantage, may be sufficient to throw it back altogether into death. Nor is the present a case of mere stoppage of the wheels of life, which, when once set in motion again, go on as well as before. Muscles once frozen, however kindly treated, eventually die sooner than those left untouched. There has been in the act of freezing a partial exhaustion of their vital forces. I ascertained, by section, that muscles which afterwards regained their irritability were frozen throughout. Hence the revival of irri- tability cannot be supposed to depend upon any part having been left unfrozen. Nor, in muscles partially frozen, did the unfrozen parts seem to have any influence over the life of the frozen parts. In muscles which have been well frozen, the fibres are more readily separable from each other, and divisible into fibrillse, than in those which die an ordinary death. Under the microscope, the fibres are clouded and more opake than usual, the transverse striae generally invisible, and in some cases the whole sarcous tissue seems to be con- verted into a confused amorphous mass, lying loose in a sarcolemma, which is more strongly defined than usual. 527 But these histological appearances have but little to do with the physiological phenomena. A muscle may be frozen so as to lose all irritability, and yet preserve its natural appearance. Two muscles may be frozen so that both shall scarcely have a fibre that is not more opake than natural and that has not lost its striae, — both, in short, shall be affected anatomically, as far as we can at present tell, to the same degree, and yet one will live and the other is dead. In muscles which never regained their irritability, the act of thaw- ing was accompanied by the onset of a peculiar rigor, which differed from the " rigor mortis," and resembled the " rigor caloris " in being an active contraction, i. e. in producing a movement. The hind leg of a frog, when rigor mortis comes on, retains the position it pre- viously had, whether of flexion or extension. Powerful excitation of the spinal cord or ischial plexus produces extreme extension. Plunging into boiling water brings the flexed leg to extreme exten- sion. If the leg be killed by frost in a flexed condition, it will when thawed assume gradually the position of extreme extension : so muscles, frozen singly, shorten when thawed. This contraction is never seen in muscles destined to regain their irritability. I have seen it come on in a muscle which had been frozen for three hours : it is a sure sign of death. This contraction continues after the production of the movement as a peculiar rigidity, which vanishes only when the softening from decomposition becomes apparent. The effect of low temperature on the frog's heart is very peculiar. There is a great diminution in the rate of rhythm, and very marked increase in the duration of each systole, so that sometimes the heart is frozen in a tetanic beat, as it were. I have never seen a frozen heart resume its beat when thawed ; but I have often seen one part of the ventricle still beating while another part was frozen quite hard. Similar results were obtained by freezing the muscles of leeches and snails. Frozen for a short time they recovered their irritability, for a longer time they died. In the latter animals, not only was mere irritability recovered, but I have seen snails, which I had every reason, by examining the state of snails of the same size frozen under exactly the same conditions, to believe had been frozen throughout, regain voluntary motion, and crawl about with extended horns as if nothing had happened. Their VOL. x. 2 o 528 slowly altered blood does not seem to lose its virtues by having passed into a state of ice. In the frog, the return of irritability is favoured by connexion with the general circulation. A frog was secured with its hind legs in a freezing mixture, the brain and spinal cord having been removed. In a few minutes the legs were frozen stiff, and had lost all irritability. After being frozen half an hour they were thawed. Irritability re- turned. Nerves, too, like muscles, lose their excitability when frozen, arid, like them, may regain it on being thawed if they have not been frozen too long. I have always found a greater difficulty in recover- ing nerves than muscles. One very curious thing is this, that, as Eckard states*, when nerves are frozen, the muscles to which they are distributed are thrown into contractions ; and yet when muscles themselves are frozen, there is not only no tetanic spasm, but not necessarily even the smallest quivering. VIII. " On the alleged Sugar-forming Function of the Liver." By FREDERICK W. PAVY, M.D. Communicated by Dr. SHARPEY, Sec. R.S. Received June 21, 1860. (Abstract.) This communication is an abridgement of a paper bearing the same title presented by the author to the Royal Society in 1858, with some additional matter, since disclosed by his experimental in- vestigations. He first shows, by analyses, that although the blood collected from the right side of the heart after death, as was formerly done, affords an abundant indication of the presence of sugar, yet that when it is removed from the same part by catheterism during life, it is found to contain but a trace of the saccharine principle. Inferences, therefore, that have been drawn of the ante-mortem state from post- mortem examinations must be abandoned as erroneous. The heart excised instantaneously after sudden killing, contains blood as free from sugar as it is during life. * Eckard, Zeitschr. f. Rat. Med. vol. x. (1851).' 529 Very slight causes are sufficient to determine the presence of a considerable amount of sugar in the circulation during life. By simply interfering with the breathing, a strongly diabetic state of the urine may be induced in an hour. To obtain a fair specimen of blood in its natural condition from the right side of the heart during life, the animal must remain in a perfectly tranquil state during the performance of catheterism. From some recent experiments, it would appear that the blood in the right side of the heart is not appreciably more saccharine than the blood in the portal vein. As in the case of the blood, the hitherto adopted mode of exami- nation of the liver has, in the author's opinion, led to a fallacious inference of its physiological state. It contains a material which is exceedingly susceptible of undergoing transformation into sugar by a process of the character of fermentation. Acids, alkalies, extreme cold, and a heat sufficient to coagulate and destroy the ferment, check this transformation. And by these agencies it may be shown, that if the liver contain any sugar at the moment of death, it is only to the extent of the merest trace. The saccharine state of the liver, which has been hitherto looked upon as belonging to life, is the result of a. post-mortem change which takes place with an astonishing rapidity. The particular part played by the liver in reference to the point under consideration, is to form a material which was originally called the glucogenic substance. As it is not considered by the author that this material is really a sugar-forming substance under physio- logical conditions, he has styled it hepatine, as belonging to the liver. This substance is doubtless intended for a special and important pur- pose in the economy, but what this purpose precisely is, must be left for the present as an open question. As one of its properties, it is most susceptible of undergoing transformation into sugar. Although in contact with a ferment, yet it resists, under natural circumstances during life, this kind of transformation. Immediately, however, that life is destroyed, the ordinary laws of chemistry come into opera- tion, and a change into sugar is effected. Abnormal states of the circulation, and probably of the blood, also lead to a similar produc- tion. Certain altered states of the nervous system likewise occasion an extensive formation of sugar in the system. 2 o2 530 After division of the spinal cord just below the phrenics, the tem- perature falls, and the transformation of hepatine into sugar after death is so slow, that the process is easily recognized under its true light. In the livers of animals naturally of low temperature, such as the frog, the oyster, and the mussel, it is a matter of the greatest facility to show that the organ is free from sugar during life, or at the period of death. The ingestion of starchy and saccharine substances leads to a great accumulation of hepatine in the liver. The liver itself becomes also greatly increased in size. The average weight of the liver in eleven dogs fed upon an animal diet was ^th that of the animal. An analysis of seven of the livers gave an average per-centage of hepatine amounting to 7*19. Five dogs upon a vegetable diet gave an average weight of liver equal to ^th that of the animal. An analysis of three of the livers gave an average per-centage of hepatine amounting to 17*23. Four dogs upon a diet of animal food with a large admixture of sugar, gave an average weight of liver equal to j^th of that of the animal. An analysis of the four livers gave a per-centage of hepa- tine precipitate amounting to 14*5. Experiments made upon the rabbit confirm these results obtained upon the dog, showing that saccharine and amylaceous materials re- ceived as food are converted by the liver into hepatine. The author looks upon this as a strong fact in opposition to the glucogenic theory. He conceives it to be in the highest degree improbable that sugar should be transformed into hepatine by the liver for the pur- pose of coming back again into sugar in the same organ. In the transformation of hepatine into sugar in the liver after death, the average of four analyses gives a loss of one part and a half of hepatine for the production of one part of sugar. Hepatine stands in direct opposition to sugar in regard to its pro- perty of diffusibility. Its power of diffusion the author has found to be so low, that it does not pass at an ordinary pressure through animal membranes. Sugar and hepatine being mixed together and placed on one side of a piece of bladder in an endosmotic apparatus, the sugar diffuses itself and leaves the hepatine behind. This phy- sical property of hepatine harmonizes with its retention in the hepatic cells under a natural state of the circulation. 531 Ligature of the portal vein causes the liver to become strongly saccharine. The blood also in the system gives a strong reaction of sugar ; and in one experiment the urine yielded just a traceable indi- cation with the copper solution. The fact that the blood thus be- comes saccharine on interrupting the flow of blood through the portal vein, stands directly in opposition to the result that might have been expected under the glucogenic theory. In a communication presented to the Royal Society in 1859, it was shown that injury to certain parts of the sympathetic system produces most rapidly a strongly diabetic state. It has since been found that the introduction of carbonate of soda largely into the cir- culation altogether prevents this eifect. IX. " A new Ozone-box and Test-slips." By E. J. LOWE, Esq., F.R.A.S., F.L.S. &c. Communicated by JOHN LEE, LL.D. Received April 16, 1860. The ordinary form of Ozone-box being very cumbersome, the pre- sent one has been contrived to supersede it*. The box is simple in construction, small in size, and cylindrical in form ; the chamber in which the test-slips are hung is perfectly dark, and at the same time there is a constant current of air circulating through it, no matter from what quarter of the compass the wind is blowing. The air either passes in at the lower portion of the box and travels round a circular chamber twice, until it reaches the centre (where the test- slips are hung) and then out again at the upper portion of the box in the same circular manner, or in at the top and out again at the bottom of the box. Fig. 1 represents a section of the upper portion of the box, showing 5. l. Fig. 2. * A specimen of the instrument was forwarded^with the paper. 532 the manner in which the air enters and moves along to the centre chamber (where the test-slip is hung at A), and figure 2 represents a section of the lower half of the box where the air circulates in the opposite direction, leaving the box on the side opposite to that on which it had entered. The box has been tested and found to work well. On three different dates, when there was much ozone, test-slips were hung in one box, whilst others were hung in another which had the two entrances sealed up in order that no current of air should pass through ; the result was satisfactory, viz. : — Example. New ozone-box. New ozone-box sealed up. 1 10 0 290 3 9i 0 Then again, in five examples of test-slips being exposed without any box, in comparison with those placed in this new box, the result was : — Example. In new ozone-box- Exposed to north without a box. 1 10 9 299 377 4 10 5 520 The ozone- box is capable of being suspended at an elevation above the ground ; and this appears to be a great advantage, because eleva- tion seems necessary in order to get a proper current of air to pass across the test-slips ; indeed as an instance it may be mentioned, that at an elevation of 20 feet there is almost always more indication of ozone than at 5 feet. The plan adopted here is to suspend the box to a "]" support, it being drawn up to its proper place by means of a thin rope passing over a pulley ; and there is less trouble in examining and changing the test-slips in this manner than there was in the old method. The box, as described, is made by Messrs. Negretti and Zambra of Hatton Garden. It has been urged that a box was scarcely necessary for ozone test-slips ; but as the papers fade on exposure to light, it must be 533 evident that in order to register the maximum amount of ozone a dark box is required. Test-slips. — Paper- slips being so fragile, I have substituted others made of calico. The calico is to all intents and purposes chemically pure, containing only a few granules of starch, used in the first pro- cess of its manufacture, which it is very difficult to remove, being enveloped in the cotton fibre ; it is, however, thought to be purer than the paper that is used for these test-slips, every precaution having been taken to make it so. Results of observations. — The following Tables have been con- structed from observations made between the 1st of May, 1859, and the 31st of March, 1860. TABLE I. Mean amount of Ozone observed from Test-slips hung for twelve hours, both at night and in the daytime, in comparison with others hung for twenty-four hours. Papers exposed for twelve hours. Papers exposed for twenty-four hours. Difference between twelve During the month of hours and twenty-four hours. Day. Night. Differ- ence. Day. Night. Differ- ence. 1859. May 0-4 1-3 0-9 1-1 1-9 0-8 07 0-6 June 0-8 0-9 0-1 1-3 1-5 0-2 0-5 0-6 July 09 10 01 1-2 1-3 0-1 0-3 03 August 07 1-4 07 1-2 1-8 0-6 0-5 0-4 September . 1-9 2-6 07 2-5 30 0-5 0-6 0-4 October ... 05 0-7 02 07 0-9 0-2 0-2 0-2 November ., 1-5 17 0-2 1-8 2-1 03 0-3 0-4 December... 17 2-0 0-3 2-1 2-5 04 0-4 05 1860. January ... 2-8 2-8 0-0 3-2 3-5 0-3 0-4 07 February ... 2-3 2-8 05 2-6 3-0 0-4 0-3 02 March 4-9 5-2 0-3 5-2 5-6 0-4 0-3 0-4 Mean 17 2-0 0-3 21 25 0-4 0-4 05 The ozone being always in excess in the night, and the tests exposed for twenty-four hours showing always an excess over those only ex- posed for twelve hours. 534 TABLE II. Number of observations without any visible ozone. Month. During the night. During the day. Twelve hours' exposure. Twenty-four hours' exposure. Twelve hours' exposure. Twenty-four hours' exposure. 1859 May 9 18 18 10 2 16 10 10 8 12 0 4 10 12 4 0 12 7 5 6 6 0 19 15 18 15 0 18 10 7 7 9 0 12 9 13 9 0 14 10 5 5 9 0 Junf July .. August September.. October ... November . . December... 1860. January ... February ... March . . . Number of days... 113 66 118 86 Mean amount of ozone with the box suspended at the height of 25 feet. 1859. December 24 hours' exposure =3*0 1860. January... 24 hours' exposure =3'9 February 24 hours' exposure =3*7 March ... 24 hours' exposure =5-9 48 hours' exposure =5'0 48 hours' exposure =4*5 48 hours' exposure =5-4 48 hours' exposure =6'4 Mean amount of ozone with the box suspended at the height of 40 feet, March 1860, with twenty-four hours' exposure =7*1. X. " On the Temperature of the Flowers and Leaves of Plants." By E. J. LOWE, Esq., F.R.A.S., F.L.S. &c. Communicated by THOMAS BELL, Esq., P.L.S., V.P.R.S. &c. Received April 16, 1860. (Abstract.) The present observations were made in order to ascertain whether different plants and flowers influence the temperature of the air immediately over them. The author was induced to undertake the inquiry from what he had noticed whilst making observations on the fall- cloud, or white mist of the valley, as it is usually called. In the autumn of 1858 it was repeatedly noticed that vapour formed first over those fields from which hay had been gathered in the summer, and which were covered with a good crop of after -math. 535 The mists then gradually formed over the shorter grass of the pasture fields, yet, unless when the fog was very thick, it never formed over stubble fields (i. e. where corn had grown). It was further observed, that at times when undrained or imperfectly-drained ploughed fields had this mist, those that were better drained were free from vapour ; moreover, the furrows or low places of a field were the spots on which fogs first formed. Hedges, on the contrary, seem to have a repulsive influence on fogs ; the author has seen a field in which the mist rose higher than the hedges, but did not flow over or even touch them, but at length poured out through the gateway in a long dense column. These peculiarities seemed to be owing either to the different tem- peratures of different trees and vegetables, or of the soils on which they grew, or perhaps to both. To determine this, the author has tested as carefully as possible the temperature of various flowers in comparison with that of grass, as well as that of different soils ; imi- tating artificially the conditions of drained and undrained fields, so that the observations might be made close together, and therefore better comparable with each other. In this latter series, which is not yet completed, and does not form part of the present paper, daily records are made of the greatest heat and cold on the surface of soils, sand, gravel, clay, &c., as well as above the ground, and from 2 to 8 inches below the surface. The thermometers employed were constructed by Messrs. Negretti and Zambra ; they are self-registering, and entirely of glass ; the de- grees being engraved on the tube, and rendered more distinctly visible by means of enamel at the back. Some of the instruments are of very small size, in order that they may be placed within the tubes of certain flowers. All the observations were carried on by myself at the Beeston Observatory. At first the thermometers were placed over the growing plant, and afterwards the flowers and leaves were arranged in bottles of water, and either exposed to full sunshine, or placed in the shade, the bottles being sunk in the ground to the level of the grass, filled with a bunch of flowers, and the thermometers placed immediately over them. With regard to the readings on the grass and on the common 536 Daisy (Bellis perennis), it should be mentioned that a portion of the grass was selected where a large group of daisies were fully in bloom, arid within a foot of this another space where every daisy was care- fully cut off from a circle of 1 2 inches, in the centre of which a second thermometer was placed on the grass, so that these records are very conclusive as regards the growing plant. Bearing upon this subject, it is proper to state, from a series of experiments with thermometers placed in full sunshine on the grass, and at 4 feet above the grass, that in winter the temperature on the grass is always lower than at 4 feet, whilst in summer the reverse takes place, the thermometers reading almost alike for a short time in spring and autumn. To this circumstance may be attributed the less striking results in hot weather, especially where the difference between the grass and a flower is only from 1° to 2°. Tables stating the details of the observations, which extended from February 26 to September 19, 1859, and from the 22nd to the 27th of March, 1860, are given in the paper. The author subjoins the following as the principal results : — Great differences occur from time to time in the temperature of plants, and much depends upon the meteorology of the day, the dif- ferences being usually greater with a cloudless sky than with one which is loaded with cloud. The time of day seems also to operate on some plants to a great degree ; as an instance, the Erica herbacea, which between 1 and 2 P.M. had shown a warmth of above 5° over that of the grass, by 3 o'clock was only 1° warmer, and by 4 o'clock was colder than the grass. In the majority of instances grass is colder than flowers, as shown by the following examples : — 1. Eleven observations on Daphne cneorum in comparison with grass. The mean gives Daphne cneorum 1°'2 warmer than grass. The temperatures range between 41° and 73°*3. In nine cases the tem- perature was warmest over Daphne cneorum, the greatest difference being 3°7. 2. Thirty-nine observations on Gentiana acaulis in comparison with grass. The mean gives Gentiana acaulis 2° warmer than grass. The temperatures range between 41° and 89°' 8. In thirty-four cases the 537 * temperature was warmest over Gentiana acaulis, the greatest differ- ence being 7°' 9. 3. Eight observations on Iberis sempervirens in comparison with grass. The mean gives Iberis sempervirens 2°'3 warmer than grass. The temperatures range between 41° and 63°' 2. In seven cases the temperature was warmest over Iberis sempervirens> the greatest difference being 3°'l. 4. Ten observations on Alyssum tortuosum in comparison with grass. The mean gives Alyssum tortuosum 2° '3 warmer than grass. The temperatures range between 41° and 88°' 9 ; in every case being warmer than grass, the greatest difference being 3°'7. 5. Eleven observations of a white Daisy in comparison with grass. The mean gives the Daisy 0°'2 hotter than grass; the range of temperature from 40°'3 to 80°'5. Greatest difference 4°-4. 6. Seven observations of Veronica alpina in comparison with grass. The mean gives Veronica alpina 1°*9 warmer than grass ; the temperature ranging from 42°*8 to 650<5. In no instance was it lower than grass. Greatest difference 5°*0. 7. Seven observations of Alyssum tortuosum in comparison with Reseda frutescens. The mean gives Alyssum tortuosum 2° '4 hotter than Reseda frutescens. 8. Thirty- three observations of Tulipa Gesneriana in comparison with grass. The mean gives Tulipa Gesneriana 1°'9 hotter than grass; the temperature ranging between 31°*4 and 96°'5. In twenty-five in- stances it was warmer than grass. Greatest difference 12°'8. 9. Twenty-eight observations of Eschscholtzia crocea in compari- son with grass. The mean gives the Eschscholtzia 3°'6 warmer than grass ; the temperature ranging between 37° and 102°*3. In twenty-four in- stances it was warmer than the grass. Greatest difference with black bulb 15°-7. 10. Ten observations ofLilium concolor in comparison with grass. The mean gives Lilium concolor 2° '9 warmer than grass ; the 538 temperature ranging between 64° and 85°* 7. In every instance it was warmer, the greatest difference being 6°'6. 1 1 . Eleven observations of Valeriana tuberosa in comparison with grass. The mean gives the Valerian 0°'5 warmer than grass; the tem- perature ranging between 52°*6 and 73°. In seven instances it was warmer than the grass, the greatest difference being 30>3. [In the last four examples the temperature at night, and the maximum with black bulb are included, so that the former will tend to lower the result and the latter to raise it.] XI. " Reduction and Discussion of the Deviations of the Com- pass observed on board of all the Iron-built Ships and a selection of the Wood-built Steam-ships in Her Majesty's Navy, and the Iron Steam-ship ( Great Eastern';" being a Report to the Hydrographer of the Admiralty. By FRE- DERICK J. EVANS, Esq. Communicated by the Lords Commissioners of the Admiralty. Received May 5, 1860. (Abstract.) The analysis of the deviations of the compass in this paper com- prises the observations made in forty-two iron ships, varying in size from 3400 to 165 tons, a selection of wood-built screw and paddle- wheel steam-vessels, as also the steam-ship * Great Eastern' at various times prior to her departure from England. The observations made in the iron-built ships extend over periods varying between thirteen and five years ; and having been made with the same description of compass — the Admiralty standard — and under similar conditions of arrangement and situation, in accordance with the system carried out in Her Majesty's Navy, details of which are given, the general results are strictly comparable. In the analysis of the Tables, amounting to nearly 250 in num- ber, of deviations observed in various parts of both hemispheres, the formula deduced from Poisson's General Equations by Mr. Archi- bald Smith, given in the Philosophical Transactions for 1846, p. 348, has been employed. In this formula, the deviation of the compass on board ship, 539 reckoned positive when the north point of the needle deviates to the east, is given by the following expression : — Deviation (S) = A + B sin % + C cos $ + D sin 2£f + E cos 2£', £ being the azimuth (by compass) of the ship's head, reckoned from the magnetic north towards the east ; A, D, E being constant coefficients depending only on the amount, quality, and arrangement or position of the iron in the ship : B and C, coefficients depending on these, and also on the magnetic dip and horizontal intensity, are each consisting of two parts ; one caused by the permanent magnetism of the hard iron, the deviation produced by which varies inversely as the horizontal force at the place ; and the other, caused by the vertical part of the earth's force inducing the soft iron in the ship, the deviation produced by which varies as the tangent of the dip : B representing that part of the combined attrac- tion acting in a fore-and-aft direction, C that acting in a transverse, or athwart-ship direction. ->C From the equation tan — g, the direction of the ship's force, and V B2 + C2j the total magnetic force of the ship in proportion to the horizontal force at the place of observation is obtained : for con- venience, 1000 has been adopted to represent the value of the earth's horizontal force at the English ports of observation, in order, by an easy comparison, to note the changes on foreign stations. By comparison of the coefficients of the several descriptions of ships, it is observed that in wood-built steam-vessels, the coefficients B and C vary nearly as the tangent of the dip ; from whence it may be inferred, as a general rule, that in steam machinery permanent magnetism bears but a small proportion to induced ; but in iron- built ships, B and C generally vary more nearly as the inverse hori- zontal force, showing that they depend more on the permanent magnetism of the iron of the ship, and thus confirming the view of the Astronomer Royal, given in his earliest deductions (Phil. Trans. 1839), that the effect of transient induced magnetism is in these ships small comparatively. Numerous examples are given in detail of this permanency of magnetism, as also of the gradual diminution of the ship's force resulting from time. An investigation of the coefficient D, which is caused entirely by the horizontal induction of the soft iron in the ship, and which is 540 known as the "quadrantal" deviation, shows, that while in wood- built steam-ships it seldom exceeds 1° or 1|°, it rises in iron-built ships from 1|° to 6° and 7°; the Liverpool Compass- Committee recording even a point of the compass. The chief characteristics of the quadrantal deviation, as developed in this investigation, are — 1. That it has invariably a positive sign, causing an easterly deviation in the N.E. and S.W. quadrants ; and a westerly deviation in the S.E. and N.W. quadrants. 2. Its amount does not appear to depend on the size, or mass of the vessel, or direction when building ; or on the existence of iron beams. 3. That a gradual decrease in amount has occurred, after the lapse of a number of years, in nearly every vessel that has been observed. 4. That the value remains unchanged in sign and amount, on changes of geographic position. 5. That a value not exceeding 4°, and ranging between that amount and 2°, may be assumed to represent the average or normal amount in vessels of all sizes. Numerous examples are given in support of these propositions, as also of the uniformity of the amount of quadrantal deviation when determined in various parts of the ship ; and, assuming the normal amount in iron steam-ships as from 2° to 4°, an analysis is given by which it is seen that 75 per cent, of the iron ships of the Royal Navy are included in this condition. Two questions of importance here arise ; are the results of this ana- lysis conclusive, and if so, under what conditions do large quadrantal deviations occur? Reverting to the Astronomer Royal's early experi- ments in 1838-39, in the iron ships ' Rainbow' and * Ironsides,' whose values were very small, and presuming that those vessels were built of good material — from their then experimental character — as also that similar conditions of material of good quality exist in the iron ships of the Royal Navy, it is assumed that the value (2° to 4°) re- presents the average condition of a ship built of the best or superior iron. On the other hand, can the inference be drawn that large quadrantal deviation in an iron ship implies that inferior material has been used 541 in her construction ? Attention is here directed to the ships ' Birken- head ' and ' Royal Charter,' which from their well-known magnetic coefficients may be regarded as the types respectively of "hard" and "soft" iron constructed vessels, and from their consideration, as also from a review of the general results, these conclusions are derived : — 1 . That in an iron ship of ordinary dimensions, a standard com- pass can be placed, the deviations of which will but little exceed those obtaining in wood-built steam-ships ; and further, that on changes of geographic position, however distant, these deviations will be within smaller limits, and can be approximately predicted. 2. A divergence from these conditions will arise when the inductive magnetism of the hull or machinery predominates ; and it is inferred, especially from the example of the ' Royal Charter/ that large qua- drantal deviation and fluctuating sub-permanent magnetism (due to hull alone) are co-existent, and give rise to conditions of compass disturbance which are beyond prediction, and which have hitherto baifled inquiry and given a complexion to theoretical deductions varying as regarded from different points of view. In order to examine the change which the original magnetism of an iron ship undergoes after launching, a series of compass observa- tions were made in the steam-ship c Great Eastern' prior to her quit- ting the River Thames in 1859, and subsequently at Portland, Holy- head, and Southampton* — at the three first-named places within short periods of time of each other. The results, from an Admiralty Standard Compass placed in a position the least subject to influence from local masses of iron, were as follows : — In the first five days, from Deptford to Portland, the ship's force had diminished from 0*585 to 0'480 [the earth's force = 1-000], or nearly one-fifth ; representing a decrease in the "semi- circular" deviation from 35° 50' to 28° 45' ; the direction of the force, or neutral points, approaching the fore-and-aft line by 10°, or changing from 47° on the starboard bow to 37°. At the expiration of the next six weeks, the ship in the interim having made the passage to Holyhead, the ship's force diminished from 0'480 to 0*390, or about one-sixth, corresponding to a decrease * The observations at Southampton were made after the paper was communi- cated to the Royal Society, and are introduced by way of supplement. 542 of " semicircular" deviation from 28° 45' to 23° 0', the direction of the force changing from 37° to 32°. At Southampton, in June 1860, or nearly eight months after the experiments made at Holyhead, the force had further diminished from 0*390 to 0'235, or by one-half, corresponding to a decrease in the "semicircular" deviation from 23° Of to 13° 30'; whilst the direction of the force approached the fore-and-aft line 25°, or from 32° to 7° ; the quadrantal deviation remaining nearly constant [-j-4l°] the whole time included in the various observations. The unvarying tendency of the direction of the ship's force in the ' Great Eastern ' to assume a fore-and-aft line, supports the view that time, with the vibrations and concussions due to sea service, leads to a distribution of the magnetic lines, of the nature of a stable equili- brium depending on the average of the inducing forces to which the ship is exposed ; the respective sections of the hull having north and south polarity, being separated by lines approximating more nearly a horizontal plane and vertical axis through the body of the ship ; instead of the inclined axis and equatorial plane of separation due to the magnetic dip of the locality, and divergence from the magnetic meridian, of the hull while building. The practical information resulting from the example of the c Great Eastern ' is, that prior to a newly built iron ship being sent to sea, her head during equipment should be secured in an opposite direction to that in which she was built ; and that the magnetic lines should be assisted to be " shaken down " by the vibrations of the machinery in a short preparatory trip prior to the determination of her compass errors, or their compensation ; but especially that in the early voy- ages vigilant supervision should be exercised in the determination of the compass disturbances. Another important point, generally neglected when compasses are adjusted by the aid of magnets in a newly built iron ship, is rendered manifest by the results of this investigation ; namely, the necessity of the errors of the compass being determined and placed on record prior to the adjustment. Without the knowledge to be derived from these observations of the magnetic force of the ship, all future changes of magnetism and consequent errors of the compass are mere guesswork both to those who adjust, and those in charge of the navigation of the ship. 543 It is recommended that, in any future legislation ibr the security of the navigation of our mercantile marine with reference to iron- built ships, the determination and record of these preliminary obser- vations should be secured. The paper concludes by directing attention to the general prin- ciples of practical import which result from the investigation, viz. as to the best direction with reference to the magnetic meridian for the keel and head of an iron ship to be placed in building, to ensure the least compass disturbance ; the best position and arrangement for a compass to ensure small deviations, and permanency on changes of geographic position ; and the changes to which the compass is liable from various causes on the foregoing conditions being fulfilled. For the best direction in building, it is shown that, from the nature of the polarity of the hull, and especially of the top sides in the after section of the ship and adjoining the compass, where usually placed, the latter is least affected in those vessels built in the line of the mag- netic meridian. For iron steam-vessels engaged in the home or foreign trades in the northern hemisphere, it is recommended, from the then antago- nistic magnetic influence of the hull and machinery, to build them head to the north : for iron sailing vessels, from the top sides, in the usual position of the compass, being magnetically weak if built head to the south, the latter direction is to be preferred. The selection for the position of the compass depends on the direction of the ship during building ; in those built head to north, it must be removed as far from the stern as convenience will permit ; in those built head to south, as near to the stern as convenient, but avoiding especially, in all cases, proximity to vertical masses of iron. In ships built head east or west, there is little choice of position : in those built on the intercardinal points, a position approximating to the stern when the action from the top-sides — to be determined expe- rimentally— is at a minimum, is to be preferred. Ample elevation above the deck and exact position in the middle line of the ship, are primary conditions to be observed ; and no com- pass should be nearer iron deck beams than 4 feet. As every piece of iron not forming a part of, or hammered in the fabrication of the hull, such as the rudder, funnel, fastenings of deck houses, &c., is of a magnetic character differing from the hull of the ship, proximity to VOL. X. 2 P 544 any such should be avoided, and, as far as possible, the compass should be so placed that they may act as correctors of the general magnetism of the hull. As most compasses are affected by the magnetism of the ship to an amount depending on their elevation, and the direction of the ship in building, the disturbances will be large comparatively, except in those vessels built head east or west. A series of Tables is appended, wherein the magnetic coefficients and ship's force and direction of the various classes of vessels are given, the ships being classed according to the nature of their mate- rial and machinery. XII. " On the Sources of the Nitrogen of Vegetation ; with special reference to the Question whether Plants assimilate free or uncombined Nitrogen." By J. B. LAWES, Esq., F.R.S.; J. H. GILBERT, Ph.D., F.R.S. ; and EVAN PUGH, Ph.D., F.C.S. Received June 21, 1860. (Abstract.) After referring to the earlier history of the subject, and especially to the conclusion of Saussure, that plants derive their nitrogen from the nitrogenous compounds of the soil and the small amount of ammonia which he found to exist in the atmosphere, the Authors preface the discussion of their own experiments on the sources of the nitrogen of plants, by a consideration of the most prominent facts established by their own investigations concerning the amount of nitrogen yielded by different crops over a given area of land, and of the relation of these to certain measured, or known sources of it. On growing the same crop year after year on the same land, with- out any supply of nitrogen by manure, it was found that wheat, over a period of 14 years, had given rather more than 30 Ibs. — barley, over a period of 6 years, somewhat less — meadow-hay, over a period of 3 years, nearly 40 Ibs. — and beans, over 1 1 years, rather more than 50 Ibs. of nitrogen, per acre, per annum. Clover, another leguminous crop, grown in 3 out of 4 consecutive years, had given an average of 1 20 Ibs. Turnips, over 8 consecutive years, had yielded about 45 Ibs. The graminaceous crops had not, during the period referred to, 545 shown signs of diminution of produce. The yield of the legumi- nous crops had fallen considerably. Turnips, again, appeared greatly to have exhausted the immediately available nitrogen in the soil. The amount of nitrogen harvested in the leguminous and root crops was considerably increased by the use of " mineral manures," whilst that in the graminaceous crops was so in a very limited degree. Direct experiments further showed that pretty nearly the same amount of nitrogen was taken from a given area of land in wheat in 8 years, whether 8 crops were grown consecutively, 4 in alterna- tion with fallow, or 4 in alternation with beans. Taking the results of 6 separate courses of rotation, Boussingault obtained an average of between one-third and one-half more nitrogen in the produce than had been supplied in manure. His largest yields of nitrogen were in the leguminous crops ; and the cereal crops were larger, when they next succeeded the removal of the highly nitrogenous leguminous crops. In their own experiments upon an actual course of rotation, without manure, the Authors had obtained, over 8 years, an average annual yield of 57' 7 Ibs. of nitrogen per acre ; about twice as much as was obtained in either wheat or barley, when they were, respectively, grown year after year on the same land. The greatest yield of nitrogen had been in a clover crop, grown once during the 8 years ; and the wheat crops grown after this clover in the first course of 4 years, and after beans in the second course, were about double those obtained when wheat suc- ceeded wheat. Thus, cereal crops grown year after year on the same land, gave an average of about 30 Ibs. of nitrogen, per acre, per annum ; and leguminous crops much more. Nevertheless the cereal crop was nearly doubled when preceded by a leguminous one. It was also about doubled when preceded by fallow. Lastly, an entirely unmanured rotation had yielded nearly twice as much nitrogen as the continuously grown cereals. Leguminous crops were, however, little benefited, indeed fre- quently injured, by the use of the ordinary direct nitrogenous ma- nures. Cereal crops, on the other hand, though their yield of ni- trogen was comparatively small, were very much increased by direct nitrogenous manures, as well as when they succeeded a highly nitro- genous leguminous crop, or fallow. But when nitrogenous manures 546 had been employed for the increased growth of the cereals, the nitrogen in the immediate increase of produce had amounted to little more than 40 per cent, of that supplied, and that in the increase of the second year after the application, to little more than one-tenth of the remainder. Estimated in the same way, there had been in the case of the meadow grasses scarcely any larger proportion of the supplied nitrogen recovered. In the leguminous crops the pro- portion so recovered appeared to be even less ; whilst in the root crops it was probably somewhat greater. Several possible explana- tions of this real or apparent loss of the nitrogen supplied by manure are enumerated. The question arises — what are the sources of all the nitrogen of our crops beyond that which is directly supplied to the soil by arti- ficial means ? The following actual or possible sources may be enumerated: — the nitrogen in certain constituent minerals of the soil ; the combined nitrogen annually coming down in the direct aqueous depositions from the atmosphere ; the accumulation of combined nitrogen from the atmosphere by the soil in other ways ; the formation of ammonia in the soil from free nitrogen and nascent hydrogen ; the formation of nitric acid from free nitrogen ; the direct absorption of combined nitrogen from the atmosphere by plants themselves ; the assimilation of free nitrogen by plants. A consideration of these several sources of the nitrogen of the vegetation which covers the earth's surface showed that those of them which have as yet been quantitatively estimated are inadequate to account for the amount .of nitrogen obtained in the annual pro- duce of a given area of land beyond that which may be attributed to supplies by previous manuring. Those, on the other hand, which have not yet been even approximately estimated as to quantity — if indeed fully established qualitatively — offer many practical difficulties in the way of such an investigation as would afford results applicable in any such estimates as are here supposed. It appeared important, therefore, to endeavour to settle the question whether or not that vast storehouse of nitrogen, the atmosphere, affords to growing plants any measurable amount of its free nitrogen. More- over, this question had of late years been submitted to very extended and laborious experimental researches by M. Boussingault, M. Ville, and also to more limited investigation by MM. Mene, Roy, Cloez, 547 De Luca, Harting, Petzholdt and others, from the results of which diametrically opposite conclusions had been arrived at. Before enter- ing on the discussion of their own experimental evidence, the Authors give a review of these results and inferences ; more especially those of M. Boussirigault who questions, and those of M. Georges Ville who affirms the assimilation of free nitrogen in the process of vegeta- tion. The general method of experiment instituted by Boussingault, which has been followed, with more or less modification, in most subsequent researches, was that adopted by the Authors in the pre- sent inquiry ; namely, to set seeds or young plants, the amount of nitrogen in which was estimated by the analysis of carefully chosen similar specimens ; to employ soils and water containing either no combined nitrogen, or only known quantities of it; to allow the access of free air (the plants being protected from rain and dust) — of a current of air freed by washing from all combined nitrogen — or of a limited quantity of air, too small to be of any avail so far as any compounds of nitrogen contained in it were concerned ; and finally, to determine the amount of combined nitrogen in the plants pro- duced, and in the soil, pot, &c., and so to provide the means of estimating the gain or loss of nitrogen during the course of the ex- periment. The plan adopted by the Authors in discussing their own experi- mental results, was— To consider the conditions to be fulfilled in order to effect the solution of the main question, and to endeavour to eliminate all sources of error in the investigation. To examine a number of collateral questions bearing upon the points at issue, and to endeavour so far to solve them, as to reduce the general solution to that of a single question to be answered by the results of a final set of experiments. To give the results of the final experiments, and to discuss their bearings upon the question which it is proposed to solve by them. Accordingly, the following points are considered : — 1 . The preparation of the soil, or matrix, for the reception of the plants and of the nutriment to be supplied to them. 2. The preparation of the nutriment, embracing that of mineral constituents, of certain solutions, and of water. 548 3. The conditions of atmosphere to be supplied to the plants, and the means of securing them ; the apparatus to Ibe employed, &c. 4. The changes undergone by nitrogenous organic matter during decomposition, affecting the quantity of combined nitrogen present, in circumstances more or less analogous to those in which the expe- rimental plants are grown. 5. The action of agents, as ozone ; and the influence of other circumstances which may affect the quantity of combined nitrogen present in connexion with the plants, independently of the direct action of the growing process. In most of the experiments a rather clayey soil, ignited with free access of air, well-washed with distilled water, and re-ignited, was used as the matrix or soil. In a few cases washed and ignited pumice- stone was used. The mineral constituents were supplied in the form of the ash of plants, of the description to be grown, if practicable, and if not, of some closely allied kind. The distilled water used for the final rinsing of all the important parts of the apparatus and for the supply of water to the plants, was prepared by boiling off one-third from ordinary water, collecting the second third as distillate, and redistilling this, previously acidulated with phosphoric acid. Most of the pots used were specially made, of porous ware, with a great many holes at the bottom and round the sides near to the bottom. These were placed in glazed stone- ware pans with inward- turned rims to lessen evaporation. Before use, the red-hot matrix and the freshly ignited ash were mixed in the red-hot pot, and the whole allowed to cool over sul- phuric acid. The soil was then moistened with distilled water, and after the lapse of a day or so the seeds or plants were put in. Very carefully picked bulks of seed were chosen ; specimens of the average weight were taken for the experiment, and in similar speci- mens the nitrogen was determined. The atmosphere supplied to the plants was washed free from ammonia by passing through sulphuric acid, and then over pumice- stone saturated with sulphuric acid. It then passed through a solu- tion of carbonate of soda before entering the apparatus enclosing the plant, and it passed out again through sulphuric acid. 549 Carbonic acid, evolved from marble by measured quantities of hydrochloric acid, was passed daily into the apparatus, after passing, with the air, through the sulphuric acid and the carbonate of soda solution. The enclosing apparatus consisted of a large glass shade, resting in a groove filled with mercury, in a slate or glazed earthenware stand, upon which the pan, with the pot of soil, &c., was placed. Tubes passed under the shade, for the ingress and the egress of air, for the supply of water to the plants, and, in some cases, for the withdrawal of the water which condensed within the shade. In other cases, the condensed water was removed by means of a special arrangement. One advantage of the apparatus adopted was, that the washed air was forced, instead of being aspirated, through the enclosing vessel. The pressure upon it was thus not only very small, and the danger from breakage, therefore, also small, but it was exerted upon the inside instead of the outside of the shade ; hence, any leakage would be from the inside outwards, so that there was no danger of unwashed air gaining access to the plants. The conditions of atmosphere were proved to be adapted for healthy growth, by growing plants under exactly the same circum- stances, but in a garden soil. The conditions of the artificial soil were shown to be suitable for the purpose, by the fact that plants grown in such soil, and in the artificial conditions of atmosphere, developed luxuriantly, if only manured with substances supplying combined nitrogen. Passing to the subjects of collateral inquiry, the first question con- sidered was, whether plants growing under the conditions stated would be likely to acquire nitrogen from the air through the medium of ozone, either within or around the plant, or in the soil ; that body oxidating free nitrogen, and thus rendering it assimilable by the plants. Several series of experiments were made upon the gases contained in plants or evolved from them, under different circumstances of light, shade, supply of carbonic acid, &c. When sought for, ozone was in no case detected. The results of the inquiry in other re- spects, bearing upon the points at issue, may be briefly summed up as follows : — 550 1 . Carbonic acid within growing vegetable cells and intercellular passages suffers decomposition very rapidly on the penetration of the sun's rays, oxygen being evolved. 2. Living vegetable cells, in the dark, or not penetrated by the direct rays of the sun, consume oxygen very rapidly, carbonic acid being formed. 3. Hence, the proportion of oxygen must vary greatly according to the position of the cell, and to the external conditions of light, and it will oscillate under the influence of the reducing force of carbon- matter (forming carbonic acid) on the one hand, and of that of the sun's rays (liberating oxygen) on the other. Both actions may go on simultaneously according to the depth of the cell ; and the once outer cells may gradually pass from the state in which the sunlight is the greater reducing agent to that in which the carbon- matter becomes the greater. 4. The great reducing power operating in those parts of the plant where ozone is most likely, if at all, to be evolved, seems unfavour- able to the oxidation of nitrogen ; that is under circumstances in which carbon-matter is not oxidized, but on the contrary, carbonic acid reduced. And where beyond the influence of the direct rays of the sun, the cells seeni to supply an abundance of more easily oxi- dized carbon-matter, available for oxidation, should free oxygen or ozone be present. As nitrates are available as a source of nitrogen to plants, if it were admitted that nitrogen is oxidated within the plant, it must be supposed (as in the case of carbon) that there are conditions under which the oxygen compound of nitrogen may be re- duced within the organism, and that there are others in which the reverse action, namely, the oxidation of nitrogen, can take place. 5. So great is the reducing power of certain carbon-compounds of vegetable substances, that when the growing process has ceased, and all the free oxygen in the cells has been consumed, water is for a time decomposed, carbonic acid formed, and hydrogen evolved. The suggestion arises, whether ozone may not be formed under the influence of the powerful reducing action of the carbon-com- pounds of the cell on the oxygen eliminated from carbonic acid by sunlight, rather than under the direct action of the sunlight itself — in a manner analogous to that in which it is ordinarily obtained under the influence of the active reducing agency of phosphorus 551 But, even if it were so, it may be questioned whether the ozone would not be at once destroyed when in contact with the carbon- compounds present. It is more probable, however, that the ozone said to be observed in the vicinity of vegetation, is due to the action of the oxygen of the air upon minute quantities of volatile carbo- hydrogens emitted by plants. Supposing ozone to be present, it might, however, be supposed to act in a more indirect mariner as a source of combined and assimilable nitrogen in the Authors' experiments, namely, — by oxidating the nitrogen dissolved in the condensed water of the apparatus — by forming nitrates in contact with the moist, porous, and alkaline soil — or by oxidating the free nitrogen in the cells of the older roots, or that evolved in their decomposition. Experiments were accordingly made to ascertain the influence of ozone upon organic matter, and on certain porous and alkaline bodies, under various circumstances. A current of ozonous air was passed over the substances for some time daily, for several months, including the whole of the warm weather of the summer ; but in only one case out of eleven was any trace of nitric acid detected, namely, that of garden soil ; and this was proved to contain nitrates before being submitted to the action of ozone. It is not, indeed, hence inferred that nitric acid could under no circumstances be formed through the influence of ozone on certain nitrogenous compounds, on nascent nitrogen, on gaseous nitrogen in contact with porous and alkaline substances, or even in the atmosphere. But, considering the negative result with large quantities of ozonous air, acting upon organic matter, soil, &c., in a wide range of circum- stances and for so long a period, it is believed that no error will be introduced into the main investigation by the cause referred to. Numerous experiments were made to determine whether free ni- trogen was evolved during the decomposition of nitrogenous organic compounds. In the first series of 6 experiments, wheat, barley, and bean-meal were respectively mixed with ignited pumice and ignited soil, and submitted for some months to decomposition in a current of air, in such manner that any ammonia evolved could be collected and estimated. The result was, that, in 5 out of the 6 cases, there was a greater or less evolution of free nitrogen — amounting, in two of the 552 cases, to more than 1 2 per cent, of the original nitrogen of the sub- stance. The second series consisted of 9 experiments ; wheat, barley, and beans being again employed, and, as before, either ignited soil or pumice used as the matrix. In some cases the seeds were submitted to experiment whole, and allowed to grow, arid the vegetable matter produced permitted to die down and decompose. In other cases, the ground seeds, or meals, were employed. The conditions of moisture were also varied. The experiments were continued through several months, when from 60 to 70 per cent, of the carbon had disappeared. In 8 out of the 9 experiments, a loss of nitrogen, evolved in the pure state, was indicated. In most cases, the loss amounted to about one-seventh or one-eighth, but in one instance to 40 per cent, of the original nitrogen. In all these experiments the decomposition of the organic substance was very complete, and the amount of carbon lost was comparatively uniform. It thus appeared that, under rare circumstances, there might be no loss of nitrogen in the decomposition of nitrogenous organic matter ; but that, under a wide range of circumstances, the loss was very considerable — a point, it may be observed, of practical importance in the management of the manures of the farm and the stable. Numerous direct experiments showed, that when nitrogenous organic matter was submitted to decomposition in water, over mer- cury, in the absence of free oxygen, no free nitrogen was evolved. In fact, the evolution in question appeared to be the result of an oxidating process. Direct experiments also showed, that seeds may be submitted to germination and growth, and that nearly the whole of the nitrogen may be found in the vegetable matter produced. It is observed that in the cases referred to, in which so large an evolution of free nitrogen took place, the organic substances were submitted to decomposition for several months, during which time they lost two-thirds of their carbon. In the experiments on the question of assimilation, however, but a very small proportion of the total organic matter is submitted to decomposing actions apart from those associated with growth, and this for a comparatively short period of time, at the termination of which the organic form is retained, and therefore but very little carbon is lost. It would 553 appear, then, that in experiments on assimilation no fear need be entertained of any serious error arising from the evolution of free nitrogen in the decomposition of the nitrogenous organic matter necessarily involved, so long as that is subjected merely to the ex- haustion required to supply materials for growth in the ordinary process of germination. On the other hand, the facts adduced afford a probable explanation of any small loss of nitrogen which may occur when seeds have not grown, or when leaves, or other dead matters, have suffered partial decomposition. They also point out an objec- tion to the application of nitrogenous organic manure in such expe- riments. Although there can be no doubt of the evolution of hydrogen during the decomposition of organic matter, and although it has long been admitted that nascent hydrogen may, under certain circum- stances, combine with gaseous nitrogen and form ammonia ; never- theless, from considerations stated at length in the paper, the Authors infer that there need be little apprehension of error in the results of their experiments, arising from an unaccounted supply of ammonia, formed under the influence of nascent hydrogen given off in the de- composition of the organic matter involved. The Authors next consider the questions, whether assimilation of free nitrogen would be most likely to take place when the plant had no other supply of combined nitrogen than that contained in the seed sown, or when supplied with a limited amount of combined nitrogen, or with an excess of combined nitrogen? And again — whether at an early stage of growth, at the most active stage, or when the plant was approaching maturity ? Combinations of these several circumstances might give a number of special conditions, in perhaps only one of which assimilation of free nitrogen might take place, in case it could in any. It is hardly to be supposed that free nitrogen would be assimilated when an excess of combined nitrogen is at the disposal of the plant. It is obvious, however, that a wide range of conditions would be ex- perimentally provided, if, in some instances, plants were supplied with no more combined nitrogen than that contained in the seed, in others brought to a given stage of growth by means of limited extraneous supplies of combined nitrogen, and in others supplied 554 with combined nitrogen in a more liberal measure. It has been sought to provide these conditions in the experiments under con- sideration. In the selection of plants, it was thought advisable to take such as would be adapted to the artificial conditions of temperature, moisture, &c. involved in the experiment, also such as were of importance in an agricultural point of view — to have representatives, moreover, of the two great Natural Families, the Graminacese and the Leguminosae, which seem to differ so widely in their relations to the combined nitrogen supplied within the soil — and finally, to have some of the same descriptions as those experimented upon by M. Boussingault, and M. G. Ville, with such discordant results. Thirteen experiments were made, 4 in 1857 and 9 in 1858, in which the plants were supplied with no other combined nitrogen than that contained in the original seed. In 1 2 of the cases pre- pared soil was the matrix, and in the remaining one prepared pumice. Of 9 experiments with graminaceous plants, 1 with wheat and 2 with barley were made in 1857. In one of the experiments with barley there was again of 0*0016, and in the other of 0*0026 gramme of nitrogen. In only two cases of the experiments with cereals in 1858, was there any gain of nitrogen indicated; and in both it amounted to only a small fraction of a milligramme. Indeed, in no one of the cases, in either 1857 or 1858, was there more nitrogen in the plants themselves, than in the seed sown. A gain was indicated only when the nitrogen in the soil and pot — which together weighed about 1500 grammes — was brought into the calculation. Moreover, the gain only exceeded 1 milligramme in the case of the experiments of 1 85 7, when slate, instead of glazed earthenware stands were used as the lute vessels ; and there was some reason to believe that the gain indicated was due to this circumstance. In none of the other cases was the gain more than would be expected from error in The result was then, that in no one case of these experiments was there any such gain of nitrogen as could lead to the supposition that free nitrogen had been assimilated. The plants had, however, vege- tated for several months, had in most cases more than trebled the carbon of the seed, and had obviously been limited in their growth 555 for want of a supply of available nitrogen in some form. During this long period they were surrounded by an atmosphere containing free nitrogen ; and their cells were penetrated by fluid saturated with that element. It may be further mentioned, that many of the plants formed glumes and paleae for seed. . It is to be observed that the results of these experiments with cereals go to confirm those of M. Boussingault. The leguminous plants experimented upon did not grow so healthily under the artificial conditions as did the cereals. Still, in all three of the cases of these plants in which no combined nitrogen was provided beyond that contained in the original seed, the carbon in the vegetable matter produced was much greater than that in the seed — in one instance mo're than 3 times greater. In no case, how- ever, was there any indication of assimilation of free nitrogen, any more than there had been by the graminaceous .plants grown under similar circumstances. One experiment was made with buckwheat, supplied with no other combined nitrogen than that contained in the seed. The result gave no indication of assimilation of free nitrogen. In regard to the whole of the experiments in which the plants were supplied with no combined nitrogen beyond that contained in the seed, it may be observed that, from the constancy of the amount of combined nitrogen present in relation to that supplied, throughout the experiments, it may be inferred, as well that there was no evolu- tion of free nitrogen .by the growing plant, as that there was no assimilation of it ; but it cannot hence be concluded that there would be no such evolution if an excess of combined nitrogen were supplied . The results of a number of experiments, in which the plants were supplied with more or less of combined nitrogen, in the form of am- monia-salts or of nitrates, are recorded. Ten were with cereals ; 4 in 1857, and 6 in 1858. Three were with leguminous plants; and there were also some with plants of other descriptions — all in 1858. In the case of the cereals more particularly, the growth was very greatly increased by the extraneous supply of combined nitrogen ; in fact, the amount of vegetable matter produced was 8, 1 2, and even 30 times greater than in parallel cases without such supply. The amount of nitrogen appropriated was also, in all cases many times 556 greater, and in one case more than 30 times as great, when a supply of combined nitrogen was provided. The evidence is therefore suffi- ciently clear that all the conditions provided, apart from those which depended upon a supply of combined nitrogen, were adapted for vigorous growth ; and that the limitation of growth where no com- bined nitrogen was supplied was due to the want of such supply. In 2 out of the 4 experiments with cereals in 1857, there was a slight gain of nitrogen beyond that which should occur from error in analysis ; but in no one of the 6 in 1858, when glazed earthenware instead of slate stands were used, was there any such gain. It is con- cluded, therefore, that there was no assimilation of free nitrogen. In some cases the supply of combined nitrogen was not given until the plants showed signs of decline ; when, on each addition, increased vigour was rapidly manifested. In others the supply was given earlier and was more liberal. As in the case of the leguminous plants grown without extraneous supply of combined nitrogen, those grown with it progressed much less healthily than the graminaceous plants. But the results under these conditions, so far as they go, did not indicate any assimilation of free nitrogen. The results of experiments with plants of other descriptions, in which an extraneous supply of combined nitrogen was provided, also failed to show an assimilation of free nitrogen. Thus, 19 experiments with cereals, 9 without and 10 with an ex- traneous supply of combined nitrogen — 6 with leguminous plants, 3 without and 3 with an extraneous supply of combined nitrogen, and also some with other plants, have been made. In none of the experiments, with plants so widely different as the graminaceous and the leguminous, and with a wide range of conditions of growth, was there evidence of an assimilation of free nitrogen. The conclusions from the whole inquiry may be briefly summed up as follows : — The yield of nitrogen in the vegetation over a given area, within a given time, especially in the case of leguminous crops, is not satis- factorily explained by reference to the hitherto quantitatively deter- mined supplies of combined nitrogen. The results and conclusions hitherto recorded by different experi- 557 menters on the question whether plants assimilate free or uncom- bined nitrogen, are very conflicting. The conditions provided in the experiments of the Authors on this question were found to be quite consistent with the healthy develop- ment of various Graminaceous Plants, but not so much so for that of the Leguminous Plants experimented upon. It is not probable that, under the circumstances of the experiments on assimilation, there would be any supply to the plants of an unac- counted quantity of combined nitrogen, due to the influence either of ozone or of nascent hydrogen. It is not probable that there would be a loss of any of the com- bined nitrogen involved in an experiment on assimilation, due to the evolution of free nitrogen in the decomposition of organic matter, excepting in certain cases when it might be presupposed. It is not probable that there would be any loss due to the evolu- tion of free nitrogen from the nitrogenous constituents of the plants during growth. In numerous experiments with graminaceous plants, under a wide range of conditions of growth, in no case was there any evidence of an assimilation of free nitrogen. In experiments with leguminous plants the growth was less satis- factory, and the range of conditions was, therefore, more limited. But the results with these plants, so far as they go, do not indicate any assimilation of free nitrogen. It is desirable that the evidence of further experiments with such plants, under conditions of more healthy growth, should be obtained. Results obtained with some other plants, are in the same sense as those with graminaceous and leguminous ones, in regard to the question of the assimilation of free nitrogen. Seeing the evidence afforded of the non-assimilation of free nitro- gen by plants, it is very desirable that the several actual or possible sources whence they may derive combined nitrogen should be more fully investigated, both qualitatively and quantitatively. If it be established that plants do not assimilate free or uncom- bined nitrogen, the source of the large amount of combined nitrogen known to exist on the surface of the globe, and in the atmosphere, still awaits a satisfactory explanation. 558 XIII. " Observations made with the Polariscope during the 'Fox' Arctic Expedition." By DAVID WALKER, M.D., Surgeon to the Expedition, — in a Report transmitted by Sir LEOPOLD McCLiNTOCK. Communicated by Professor STOKES, Sec. U.S. Received March 7, 1860. The observations made with the polariscope*, with one exception, were confined to solar halos and parhelia. Several times I tried the instrument when lunar halos appeared, but the light was so faint that only once was I able to make an observation. The direction of the polarization was the same in all the cases observed, namely, in a plane parallel to a line joining the part looked at with the centre of the sun or moon. In several instances the instrument was turned round so as to find the plane of maximum polarization, but it was always found greatest in the parcel or perpendicular plane : when the plane was oblique, no perceptible polarization at all was perceived. The light was never completely polarized, the greatest amount not being more than half; such occurred on 21st of April, and 5th and 6th of May 1859. All the halos observed had a diameter of about 45°: there were some seen of diameter 90°, but the polariscope was not at hand at the time. Almost always the halos round the moon or sun were more or less prismatic, red internal. The observation on October 10th, 1857, was not on a halo, but the cloud which surrounded the moon at a distance of about 1^° had circular and prismatic edges ; light from these edges was slightly polarized, but not of the same image as in all the other instances. Moon. October 7th, 1857. — Polariscope applied to a halo round the moon, diameter about 45° ; slight polarization ; arrow and brighter image * The polariscope employed consisted merely of a double-image prism of quartz, formed of two quartz prisms cut in the usual manner and cemented toge- ther, which was fixed at the eye-end of a tube about 18 inches long, provided at its other end with a rectangular aperture having its edges parallel and perpendi- cular to the planes of polarization of the two images, and of such breadth that the two images just touched each other along one edge. The plane of polarization of that image which was polarized in a plane passing through the axis of the instru- ment, was marked by an arrow at the eye-end, lying in that plane, and placed on the same side of the axis as the image in question. 559 both being to the left when the instrument was held parallel to a line joining a part of halo to the left of the moon with the moon. October 10th, 1857. — Polariscope applied to a prismatic luminous haze round the moon, three diameters of moon's radius; slight polari- zation, the image to the right hand being brighter, mark on eye-end to left hand ; instrument held horizontal, looking at the haze to the right of the moon. Sun. March 18th, 1858. — Prismatic halo round the sun's diameter about 45°, with two parhelia, one on each side of the sun ; instrument applied to the left parhelion ; slight polarization, the outer or left image being brighter when the instrument was held in a plane parallel to a line joining the sun and parhelion, the eye-mark and brighter image both to the left. May 15th, 1858. — Prismatic halo round sun, diameter about 45°, with two parhelia, one on each side. The instrument held in same azimuth as last observation, looking at left parhelion ; a little stronger polarization, the outer image being brighter. May 25th, 1858. — Appearances in neighbourhood of sun and par- A. Sun's altitude, 39° 15'. B. Circle running round heavens, 101° diam. C. Circle 22° in radius, passing round A and intersecting B. D. A parhelion occurring on circle C. E. An oval arc, radius horizontally 27° 30', perpendicularly 22°, F. Parhelion occurring on circle C. G. Part of a circle passing through F, 17° 15' above horizon. H and I. Two parhelia on horizontal circle (101° diameter), each distant from sun 25° 30'. VOL. X. 2 Q 560 helia at 1'45 P.M. :— Sun's altitude 39° 15'. A circle of diameter 101° running round heavens and passing through the sun, intersected by another circle, radius 22°, having the sun for its centre. Another intersection took place at 27° 30' from the sun, on each side, by an arc (perpendicular), which coincided with the previous circle at an altitude of 22° from the sun. Four parhelia appeared, one on each side of the sun, one above and one below ; through the lower one passed part of an arc of another circle. Polariscope applied to left- side parhelion and also to halo, slight polarization of outer or left image ; instrument held in a plane parallel to a line joining parhelion and sun. July 16th, 1858, 10'40 P.M. — Prismatic parhelia 22° 30' on each side of sun ; altitude 7°. Polariscope held in a parallel plane ; parhelion on left of sun looked at ; slight polarization ; bright image and eye-mark both to the left hand. November 8th, 1858, 10A.M. — Prismatic parhelion distant about 23° from each side of sun ; altitude 6°. Polariscope applied to left image, held horizontally (parallel), eye-mark to left ; slight polariza- tion, image to left and further from sun brighter. Instrument held in same plane, but with eye-mark to right, applied to right parhelion ; similar slight polarization, image to right and furthest from the sun brighter. March 30th, 1859, 4 P.M. — Prismatic parhelia about 23° distant from each side of sun. Polariscope applied to image on left of the sun, held parallel, eye-mark to left ; slight polarization, image to left and further from the sun brighter. Instrument held in same plane, but eye-mark to right ; slight polarization, image to right and outer being the brighter. April 21st, 1859, 7 P.M. — Prismatic parhelion and part of halo on each side of sun distant about 22° 30f. Polariscope applied to left-hand image, held in a parallel plane, eye-mark to left ; medium polarization, the left or outer image brighter. Instrument held in same plane with eye-mark to right, and applied to right-hand image ; similar medium polarization, image to right and further from the sun brighter. May 1st, 1859, 6 P.M. — Prismatic parhelion with part of a halo on each side of sun distant 23° (about). Polariscope applied to left image, held parallel, eye-mark to left ; slight polarization, left or outer image brighter. Instrument held in same plane, eye-mark to 561 right and applied to right image ; slight polarization, outer or right image being brighter. May 5th, 1859, 8 P.M. — Prismatic parhelion with part of halo on each side of sun distant about 22° 30'. Polariscope applied to left image, held in a parallel plane, eye-mark to left ; medium polariza- tion, left or outer image brighter. Instrument held in same plane and applied to right image, eye-mark to right ; similar medium pola- rization, outer or right image brighter. May 6th, 1859, 6 '50 P.M. — Prismatic parhelion and part of halo on each side of sun distant 22° 20'. Polariscope applied to left image and held in a parallel plane, eye-mark to left ; medium po- larization, outer or left image being brighter. Instrument held in same plane, eye-mark to right, and applied to the right parhelion ; similar medium polarization, right or outer image being brighter. May 20th, 1859, 8 P.M. — Prismatic arc of halo to left of sun distant about 23°. Polariscope applied, held in the parallel plane, eye-mark to left ; slight polarization, the outer or left image being brighter. August 7th, 1859, 7*30 P.M. — Prismatic parhelion to right of sun, distant about 22° 30'. Polariscope applied, held in the plane of a line joining sun and parhelion ; a little more polarization than in last observation. Arrow and brighter image both to the right. XIV. " Notice of < The Royal Charter Storm ' in October 1859." By Rear- Admiral ROBERT FiTzRoY, F.R.S. Received June 21, 1860. (Abstract.) The author commenced with some remarks on the recent progress of meteorology, on its advances towards precision and consistency as a science, and the comparative certainty and confidence \\ith which it may now be relied on in its practical applications. He adverted also to the measures now systematically adopted by the Meteorolo- gical Department of the Board of Trade and by the Admiralty for promoting simultaneous meteorological observations at various places, and for obtaining accurate registration of atmospherical conditions at sea and on land in many parts of the world ; and drew attention to 562 the steps taken by these public departments for diffusing practical knowledge concerning the laws of winds and storms, and of weather in general, among mariners and others more especially standing in need of such information, as well as to the practice now followed, of lending trustworthy meteorological instruments to commanders of ships able and willing to make an adequate return in the shape of accurate meteorological records, and of supplying other such aids, of a kind specially suited to their wants, to various of the most exposed and least affluent fishing villages. Notice was then taken of some of the more important practical results derived from meteorological inquiry, — especially the remark- able fact, now fully established, of the constancy of barometric pressure between five and ten degrees of north latitude ; the phe- nomena of cyclones, and the explanation afforded of their production, following Dove's theory of polar and equatorial currents in the atmo- sphere. In treating of the main subject of his communication, the " Royal Charter Storm " and the severe gale of the first two days of Novem- ber last, the author made use of illustrative diagrams, which were exhibited to the Meeting. Of these, four, of large size, showed suc- cessive phases of the storm on the 25th and 26th of October ; the first at 9 A.M. and the second at 3 P.M. on the 25th; the third at 3 A.M. and the fourth at 9 A.M. on the 26th. These were intended to show simultaneous or synchronous direction and force of wind over a certain area within a few minutes of time, any noteworthy difference of longitude having been allowed for. Smaller diagrams, in like manner, showed simultaneous direction and force of wind from the 22nd of October to the 2nd of November. In both cases the direction was indicated with reference to the true meridian, and the force according to estimation only, which, however, was checked by many comparisons with velocities and pressure instrumentally ob- tained at the observatories of Greenwich, Cambridge, Oxford, Wrottesley, Liverpool, and at other well-known establishments. The same charts also showed curves of barometric pressure and curves of temperature. These diagrams or charts were compiled by Mr. Ba- bington, assisted in copying by Messrs. Pattrickson, Simmonds, and Symons ; but notwithstanding the large amount of materials already made use of in their compilation, the author observed that 563 none of them, nor indeed any part of the work, could yet be con- sidered as nearly complete, and that much matter would still be added as, from time to time, information might be obtained from various sources. The storm of the 26th of October was first noticed in accurate records, and measured by instrumental observations, in the Bay of Biscay, near Cape Finisterre in Spain. This particular tempest did not come from the west, but from the south-south-west, true. Successive barometric effects of the storm were traced by similar means in that direction from S.S.W. to N.N.E. across England, from the Channel through Cornwall, across the central southern counties and Lincolnshire, over the North Sea to between the Shetland Isles and Norway. By referring to these charts and the diagrams, it will be seen that the lowest barometer and a corresponding or simultaneous lull pre- vailed over ten, fifteen, or twenty miles consecutively in the direc- tion pointed out. But at the time that this comparative lull existed there was around this centre, by some called a vortex (but it can hardly be appropriately so termed, because there was no central disturbance), only variable wind or calm for a short time in the middle of the space, which was about ten or fifteen miles in irregular area. The wind obtained a varying velocity of from 60 to 100 miles an hour at a distance of from twenty to about fifty miles from this space, and in unequal eddyings crossed England towards the north-north- east, the wind blowing from all points of the compass around the lull. When at Anglesea the storm came from the north-north-east, in the Straits of Dover it was from the south-west ; on the east coast it was easterly ; in the Irish Channel it was northerly, and on the coast of Ireland it was from the north-west. The charts show that this circulation or cyclonic commotion was passing northwards from the 25th to the 27th, being two complete days from the time of its first great strength in the " Chops of the Channel," while outside of this circulation the wind became less and less violent ; and it is very remarkable that even so near as on the west coast of Ireland there was fine weather with light winds, while in the British Channel it blew a furious northerly and westerly gale. At Galway and at Limerick on that occasion there were light 564 winds only, while, as already stated, over England, the wind was passing in a tempest, blowing from all points of the compass around a central lull. The next storm that occurred was similar in its features, though it came from a rather different direction. It raged on the 1st and 2nd of November, and its character was in all respects like that just described, now usually called the "Charter Storm/' Coming more from the westward, it passed across the north of Ireland, the Isle of Man, north of England, and then across the North Sea towards Denmark. Further than that distance facts have not yet been gathered, but in the course of time they will be obtained and collated. The general effect of these storms was felt unequally in our islands, and much less inland than on the coasts. Lord Wrottesley has shown by observations made at his obser- vatory in Staffordshire, that the wind is diminished or checked by its passage over land ; and, looking to the mountain ranges of Wales and Scotland, rising 2000, 3000, or 4000 feet above the level of the ocean, we see they must have great power to alter the direction and probably the velocity of wind, independently of alterations caused by changes of temperature. The very remarkable similarities of this storm of the 1st and 2nd of November, that of the 25th and 26th of October, the series of storms investigated -by Dr. Lloyd during ten years, and the observations of Mr. William Stevenson in Berwick- shire, require special notice on this occasion. There is no discre- pancy between the results of the ten years' investigations published by Dr. Lloyd in the Transactions of the Irish Academy, the three years' inquiry published by Mr. William Stevenson, and all the investigations which have been brought together during the last four years. They all tell the same story. Dr. Lloyd only found in ten years one instance of even a partial storm which differed, namely, one that came from the north in the first instance. Storms from the south-west are followed by sudden and dangerous storms from the north or east, and these are the storms that do most damage on our coasts. Upon tracing the facts, it is proved that the storms which come from the west and south come on gra- 565 dually, but that storms from the north or east begin suddenly, and at times with extraordinary force. The barometer, with these north-eastern storms, does not give so much warning upon this coast, because it ranges higher than with the wind from the opposite quarter. But though the barometer does not give much indication of a north-eastern gale, the thermometer does, and the now well-known average temperature of every week in the year affords the caution. The temperature being much above or below the mean for the time of year shows whether the wind will be northerly or southerly — thanks to Mr. Glaisher's discussion of the Greenwich observations for temperature. To revert to a few of the signs which preceded the "Charter Gale." For a few days before that storm came on, the thermometer was ex- ceedingly low over all the country ; there were north winds in some places, and a good deal of snow ; though there had been a great deal of exceedingly dry and hot weather previously. These anomalies require consideration ; and it may be mentioned that everywhere in these islands, for days before that time, from the 22nd to the 25th of October, barometers were very low. Many days preceding the Char- ter storm, an extraordinary clearness in the atmosphere was noticed in the north of Ireland ; the mountains of Scotland were never seen so prominently as they were in the few days preceding those on which the great storm took place. Every one is aware that last sum- mer was remarkable for its warmth. It was exceedingly dry and hot. All over the world, not only in the Arctic, but in the Antarctic regions, in Australia, South America, in the West Indies, Bermudas, and elsewhere, auroras and meteors were unusually prevalent, and they were more remarkable in their features and appearances than had been noticed for many years. There was also an extraordinary dis- turbance of currents along telegraph wires. They were so disturbed at times, that it was evident there were great electric or magnetic storms in the atmosphere, though they could be traced to no appa- rent cause. Probably these electric disturbances were connected with a peculiar action of the sun upon our atmosphere. Submarine wires, as well as electrical wires above ground, were unusually disturbed, and these disturbances were followed within two or three days by great com- motions in the atmosphere, or by some remarkable change. 566 The question of areas of barometric pressure — or lines (which Espy contends for), namely, long lines from north to south, or from one point direct to another, having been much discussed, the principal object of making the sections, as it were soundings, of the atmo- sphere which are shown in the diagrams, was to prove whether lines of pressure, or whether areas of pressure prevailed ; and in the author's opinion, when they are closely examined they go to prove that while the atmosphere in the British Islands varies in its pressure from time to time, such variation is not along a particular line, but extended over a large and wide area. As remarkable exceptions to the force of these particular storms, it may be noted that at some places there was little or no wind ; although the barometer fell much, without any consequence but rain. The wind circulating around these districts did not affect them, while at other places the storm was tremendous. The following few details are given respecting the data on which the diagrams have been constructed : — The probable limits of error of the barometric curves on the synoptic charts, 2\st October to 2nd November, 1859. 1. Observations quite correct. — The observations at the regular observatories, such as Greenwich, Oxford, Cambridge, Wrottesley, Highfield House, Kew, &c., have had all corrections applied, and have been reduced to sea-level, and the temperature of 32° Fahr- enheit. 2. Error probably very small, less certainly than half a tenth. — The returns from members of the British and Scottish Meteorological Society (nearly ninety in number) have been corrected for height above sea-level, within a few feet ; and the corrections of instru- mental errors with reductions to 32° have been applied. Observations probably within a few hundredths of an inch. — The continental observations, collected from Dutch papers and from the " Moniteur," have been reduced to 32°, and have also been corrected for instrumental errors. The heights of some stations are known, and the corrections due to those heights have been applied, while others are but little, if at all, above the sea-level. 567 Any error in laying down curves from these data can scarcely have exceeded two or three hundredths of an inch. 3. Observations less accurate. — The heights of the stations of some observers are not known so nearly. Other corrections have been applied only in a few cases, — the observations sometimes recorded only to the nearest tenth, as at a few lighthouses, not being deemed sufficiently reliable. Returns in which the barometrical observations are evidently erro- neous (from comparison with other neighbouring and contempora- neous observations) have been rejected. On the whole it may be safely assumed that the observations from which the curves are laid down are less than a tenth in error. 4. Lighthouses. — The heights of the lantern above the sea- level, and of the tower, being known, the heights of the barometers have been ascertained, and corrections for the heights have been applied. Comparisons of Wind Scales. Sea. Wind. Land. 0 to 3 Light 0 to 1 3 to 5 Moderate 1 to 2 5 to 7 Fresh 2 to 3 7 to 8 Strong 3 to 4 8 to 10 Heavy 4 to 5 10 to 12 Violent 5 to 6 Wind. No. Velocity. Pressure Ibs. (avoirdupois). (land scale). Miles (hourly). i- i 10 5 2 32 10 3 45 21 4 65 26 5 72 32 6 80 These comparisons of scales have been used in the wind charts, and have been found convenient as well as sufficiently accurate. 568 XV. •" Contributions to the History of the Phosphorus Bases." Parts I., II. and III. By A. W. HOFMANN, LL.D., F.R.S. &c. Received June 21, 1860. »" This paper contains the first three sections of the full and syste- matic exposition of the author's Researches on the Phosphorus Bases, of which brief notices have from time to time been communi- cated by him to the Society, and printed in the * Proceedings.' The present communication comprehends I. Deportment of Triethylphosphine with Sulphur com- pounds. Nitro-phosphuretted Ureas. II. Theory of Diatomic Bases. Diphosphonium Series. III. Theory of Diatomic Bases. Phosphammonium — and Phospharsonium Series. COMMUNICATIONS RECEIVED SINCE THE END OF THE SESSION. I. "On Boric Ethide." By EDWARD FRANKLAND, Ph.D., F.R.S., and B. DUPPA, Esq. Communicated by Dr. FRANKLAND. Received July 7, 1860. When zincethyl in excess is brought into contact with tribasic / fC.H.O.\ boracic ether, I B< C4H5O2 I, the temperature of the mixture era- V tC4H502/ dually rises for about half an hour. If it be now submitted to distillation, it begins to boil at 94° C., and between this temperature and 140° a considerable quantity of a colourless liquid distils over. The distillation then suddenly stops, the thermometer rises rapidly, and, to avoid secondary products of decomposition, the operation should now be interrupted. The materials remaining in the retort solidify, on cooling, into a mass of large crystals, which are a com- pound of ethylate of zinc with zincethyl. On rectification, the distil- late began to boil at 70°, but the thermometer rapidly rose to 95°, at which temperature the last two-thirds of the liquid passed over and were received apart. The product thus collected exhibited a con- 569 stant boiling-point on redistillation. Submitted to analysis, it yielded results agreeing with the formula This body, for which we propose the name boric ethide, is pro- duced by the following reaction : — {C4H3O3 fr TT fQlH- r F C4H502 + 3Zn2{£H5=2BJ C4H5 + 6C* C4HS02 L^U5 \.C4H5 Boracic ether. Zincethyl. Boric ethide. Ethylate of zinc. The ethylate of zinc thus formed combines with zincethyl to form the crystalline compound above alluded to. Boric ethide possesses the following properties : — It is a colourless mobile liquid of a pungent odour ; its vapour is very irritating to the mucous membrane, and provokes a copious flow of tears. The spe- cific gravity of boric ethide at 23° C. is -6961 ; it boils at 95° C., and the results of several determinations of its vapour-density give the number 3*4006. The calculated vapour-density of boric ethide, volumetrically composed like terchloride of boron, is 3*3824. Boric ethide is insoluble in water, and is very slowly decomposed by prolonged contact with it. Iodine has scarcely any action upon it, even at 100° C. It floats upon concentrated nitric acid for several minutes without change ; but suddenly a violent oxidation takes place, and crystals of boracic acid separate. When boric ethide vapour comes in contact with the air it produces slight bluish-white fumes, which have a high temperature. The liquid is spontaneously in- flammable in air, burning with a beautiful green and somewhat fuli- ginous flame. In contact with pure oxygen it explodes. Placed in a flask and allowed to oxidize gradually, first in dry air and finally in dry oxygen, it forms a colourless liquid, which boils at a higher tem- perature than boric ethide, but cannot be distilled under atmospheric pressure without partial decomposition. In a stream of dry carbonic acid this product of oxidation evaporates without residue. By distil- lation in vacuo it is obtained pure, and it then exhibits a composition expressed by the formula fC4Hs B< C.H.O, LC.H.O, 570 The product of the oxidation of boric ethide is therefore the di- ethylate of a body which maybe conveniently named boric dioxyethide, . The formation of diethylate of boric dioxyethide from boric ethide may be thus represented : t- o4 = Boric ethide. Diethylate of boric dioxyethide. This compound dissolves instantly in water, and is resolved into alcohol and a volatile white crystalline body, which may be sublimed without change, at a gentle heat, in a stream of carbonic acid, and then condenses in magnificent crystalline plates like naphthaline. The analytical results yielded by this body agree closely with the formula BJHO,' IHO| It is therefore obviously produced by the substitution of two atoms of hydrogen for two of ethyl in diethylate of boric dioxyethide : C\ EL CC4 II Diethylate of boric Dihydrate of boric Alcohol, dioxyethide. dioxyethide. Dihydrate of boric dioxyethide possesses an agreeable etherial odour and a most intensely sweet taste, Exposed to the air it evaporates slowly at ordinary temperatures, undergoing at the same time partial decomposition, and invariably leaving a slight residue of boracic acid. Its vapour tastes intensely sweet. It reddens litmus paper, although in other respects its acid qualities are very obscure. It is very soluble in water, alcohol, and ether. Exposed to a gentle heat it fuses, and at a higher temperature boils with partial decom- position. We are at present engaged with the further study of these bodies, and with the corresponding reactions of zincethyl upon silicic, car- bonic, and oxalic ethers. 571 II, " On Fermat's Theorems of the Polygonal Numbers." First Communication. By The Eight Hon. Sir FREDERICK POLLOCK, F.R.S., Lord Chief Baron. Received July 11, 1860. (Abstract.) This paper relates to the second theorem, viz. that which asserts that every number is composed of 4 square numbers (0 [or zero] being considered as an even square). If every odd number be com- posed of 4 square numbers, then every even number must also be composed of 4 square numbers ; for every even number must, on a continued division by 2, ultimately become an odd number. The paper relates chiefly to the Table which accompanies it, from which it appears that a remarkable law obtains as to the division of odd numbers (2n+\) into 4 square numbers — when a number of the form 4w -fl is divisible into 2 square numbers, which (as 4n+l is an odd number) must be one of them odd, the other even. Before explaining the Table, it is proper to state that if an odd number be divisible into 4 square numbers, three of them must be odd, and one of them even, or one of them must be odd, and 3 of them even, other- wise their sum cannot be an odd number ; it follows from this that if the difference between any two of them be an odd number, the differ- ence between the other two must be an even number, and vice versa-, for let a2 -f 62 + c2 + d2=2ra+ 1, then if «2-62=2p, c2-^2 must equal 20-f 1; if possible let c2-^=2r, then a2— 62 + c2-d2=2p-f 2r . add 2b2 + 2d2 (an even number) to each, and a2 + 52 + c2 -f- d2 will be an even number, which by the hypothesis it is not ; if, therefore, #3— 52 be an even number, c2— c?2 cannot also be an even number, and therefore must be an odd one. If, therefore, the four roots of the squares into which any odd number may be divided are arranged in any order there will be three differences ; the two exterior differences will be one odd, the other even ; the middle difference may be either odd or even. The Table is arranged thus : — the lowest row of figures is the series 1, 5, 9, 13, 17, &c. (4w+ 1) ; the next row above is the series of natural numbers, 0, 1, 2, 3, 4, &c. (w), &c. ; the next row is 1, 3, 5, 7, 9, &c. (2ra+l) the odd numbers; each of the odd numbers is the first term in a series increasing upwards by the num- 572 bers 2, 4, 6, 8, 10, &c., forming an arithmetic series of the second order (the first and second differences being respectively 2 each) ; when the number in the lowest row cannot be divided into 2 squares, the arithmetic series is not formed, and the squares are marked with an asterisk, but when the number 4n+ 1 is divisible into 2 square numbers, the roots of these squares constitute the two exterior dif- ferences of the roots into which the odd number may be divided, and also of the roots into which each term of the series increasing upward may be divided ; the middle difference of the roots will be the smaller half of the sum of the 2 roots of the square numbers into which 4n+ 1 may be divided, with a negative sign, and will increase by 1 in each successive term of the upward series. For example, in the Table take the number 29 in the lowest row, 7x4 + 1 = 29, 7 is the number above it, and 7x2 + 1 = 15 the odd number, which is the first term of the series 15, 17, 21, 27, 35, &c. Now 29 is composed of 2 square numbers, 4 and 25, whose roots are 2 and 5, 2 + 5 = 7; the smaller half is 3, and 2, —3, 5 will be the differences of the roots of the squares into which 15 may be divided, and whose sum will equal 1 ; thus 2, -3, 5 -1, 1, -2,3; the roots when squared and added together equal 15, and the other terms of the series follow in like manner, obeying the law indicated ; thus 5, -2, 2 3, 2, 0, 2 when squared and added . =17 2, -1,5 —2, 0, — 1, 4 when squared and added . =21 5,0,2 —4, 1, 1, 3 when squared and added . =27 2, 1,5 — 3, —1, 0, 5 whose squares .... =35 The proof of all this depends on a property of numbers mentioned in the Philosophical Transactions for 1854, vol. cxliv. p. 317. If any number be composed of two triangular numbers, it will also equal a square and a double triangular number. If it will be of the form «2 + a + 62, and may be assumed equal to 573 a2 + a-|_62. For if 2 numbers be both odd or both even, they may always be represented by 0 + 6 and 0—6; if one be odd and the other- even, they may always be represented by a + 6+1 and a — 6, or by a + b and a — 6 + 1 ; and if the two numbers be made the bases of trigonal numbers, the sum of the two trigonal numbers will always be of the form a2 + a + 62, or 02 + b + b2 : now when any number in the natural series of numbers is composed of two trian- gular numbers, it may be represented by 02 + a + 62, and 4n + 1 will then equal 402 + 40 + 1 +462, — obviously the sum of an odd and an even square, whose roots are 26 and 20+ 1 ; and 2w+ 1, the corre- sponding odd number, will equal 202 + 20 + 1 + 262, — obviously com- posed of 4 square numbers, whose roots are 6, 6, 0, 0 + 1 ; and if they be arranged thus, 26, — (0 + 6)20+1 — 6, 6, — 0, 0+1, so that the sum of their roots may equal 1, the exterior differences of the roots will be 26 and 20+1, the roots of the two squares into which 4w+ 1 is divisible ; and the middle difference will be — (a + 6), the smaller half of the sum of the roots (26 + 20+1) with a nega- tive sign ; if the exterior differences be reversed and the middle dif- ference be increased by 1, the differences will be 20 + 1, — (a + 6 — 1), 26, and the roots whose sum will equal 1 will be, with their differ- ences above them, 20 + 1, -(0+6-1), 26 -(0+1), «-(6-l), 6 + 1, and the sum of the squares of the roots will be 2 more ; from these two sets of roots all the rest may be obtained, by adding one to each of two roots and subtracting 1 from each of the other two roots ; the exterior differences of the roots will therefore always be the same, and the middle difference will increase by 1 at each step ; the sum of the squares of the roots will increase by 2, 4, 6, 8, &c. As the sum of any two square numbers of which one is odd and the other even (402 + 40+l +462) must be of the form 4ra+l, every possible case of an odd square combined with an even square must occur somewhere in the series 1, 5, 9, 13, &c., and the Table (if extended) must contain every possible case of odd 574 and even numbers as exterior differences, combined with every pos- sible and available middle difference ; for negative differences may be rejected, inasmuch as, if the roots be put according to their algebraic value, all the differences must be even ; thus the roots and differences of 15 above were 2, -3, 5 -1, 1, -2,3; if the roots be placed according to their algebraic value, they would be —2, — 1, 1, 3, and with the differences above 1,2,2 -2, -1, 1,3; 15 will therefore be found in the column above 5, and in the fourth place. The Table (extended indefinitely) would therefore contain every possible odd number the sum of whose roots may equal 1 . It is possible that this connexion between the roots of the squares into which 4n+l maybe divided, with the exterior differences of the roots of the four square numbers into which 2n + 1 may be divided, formed part of the mysterious properties of numbers to which Fermat alluded when he announced the theorems of the poly- gonal numbers. III. " On Cyanide of Ethylene and Succinic Acid."— Prelimi- nary Notice. By MAXWELL SIMPSON, Ph.D. Communi- cated by Dr. FRANKLAND, F.R.S. Received August 1, 1860. Succinic acid bears the same relation to the diatomic alcohol (glycol) that propionic acid bears to ordinary alcohol. Propionic acid can be obtained by treating the cyanide of the alcohol radical with potash. Can succinic acid be obtained by treating the cyanide of the glycol radical with the same reagent, or is it an isomeric acid that is formed under these circumstances ? C4H5, Cyanide of ethyl. Propionate of potash. Cyanide of ethylene. Succinate of potash ? 575 The following experiments were performed with the view of deter- mining this point : — Preparation of Cyanide of Ethylene. — As a preliminary step to the formation of succinic acid in this way, it became of course neces- sary to prepare the cyanide of ethylene. This body I obtained by submitting bromide of ethylene to the action of cyanide of potassium. The process was thus conducted : — A mixture of two equivalents of the cyanide and one of the bromide was introduced into a large balloon, together with a considerable quantity of alcohol, sp. gr. *840, and exposed to the temperature of a water-bath, a Liebig's condenser having been previously attached to the balloon in such a manner as to prevent the alcohol from distilling off the reacting ingredients. As soon as all the cyanide of potassium had been converted into bro- mide, the alcohol was separated and distilled. A semifluid residue was thus obtained, which was filtered at the temperature of 100° Cent. On treating the nitrate with a saturated solution of chloride of calcium, a reddish oil rose to the surface, which was well washed with ether, and exposed for some time to the temperature of 140°, in order to remove any bromide of ethylene that might have escaped the solvent action of the ether. This body proved, on analysis, to be cyanide of ethylene. It was not, however, quite pure. There are difficulties attending its complete purification which I have not yet overcome. At the temperature of the air, cyanide of ethylene is a semisolid crystalline mass of a brownish colour. It melts under 50° Cent. It is very soluble in water and alcohol, and sparingly soluble in ether. It cannot be distilled. Nevertheless it bears a tolerably high tem- perature without suffering much decomposition. Heated with an alcoholic solution of potash, it gives off ammonia. Treated with nitric acid, it forms a body which crystallizes from alcohol in long needles. This and some other reactions I am at present engaged in studying. Preparation of Succinic Acid. — Bromide of ethylene and cyanide of potassium were made to react upon each other in the same manner as in the preparation of the cyanide of ethylene. As soon as the re- action was complete, the alcohol was separated from the bromide of potassium, some sticks of caustic potash were added to it, and the whole heated for several days by means of a water-bath. Torrents of VOL. x. 2 R 576 ammonia were given off on applying the heat. As soon as the evolution of this gas had ceased, the alcohol was distilled off and the residue treated with a considerahle excess of hydrochloric acid. This was then heated gently as long as acid vapours continued to be evolved, digested with absolute alcohol, and filtered, and then the filtrate was evaporated to dryness. The dry mass thus obtained was treated several times with alcohol in a similar manner. The result of these repeated digestions was then dissolved in water, and a few drops of a solution of nitrate of silver were added to it, which occasioned a slight precipitate of chloride of silver. This was separated by filtration, and the filtrate was exactly neutralized with ammonia. On adding excess of nitrate of silver to this, an abundant white precipitate was obtained, very soluble in nitric acid and ammonia. This gave, on analysis, numbers agree- ing very well with the composition of succinate of silver. The acid itself possessed also all the properties of succinic acid. It sublimed on the application of heat, was soluble in water, alcohol, and ether, and gave, when neutralized, a reddish-brown precipitate with per- chloride of iron. Moreover, on digesting this precipitate with am- monia, an acid could be detected in the filtered liquor, which gave white precipitates with nitrate of silver, and with a mixture of chlo- ride of barium and alcohol. Succinic acid can then be obtained from glycol in the same manner as propionic acid from ordinary alcohol ; the bromide of ethylene, the point from which I started, being capable of derivation from the diatomic alcohol. I propose extending this investigation to some other hydrocarbons of the series Cn Hn, with the view of ascertaining whether or not the homologues of succinic acid can be obtained from these bodies by a similar process. IV. "Results of Researches on the Electric Function of the Torpedo." By Professor CARLO MATTEUCCI of Pisa. In a Letter to Dr. SHARPEY, Sec. R.S. Received August 3, 1860. (Extract.) " It has hitherto been believed that the action of the electric organ of the Torpedo was momentary only; — that it becomes charged 577 under the influence of nervous action and discharged immediately that action ceases, somewhat like soft iron under the influence of an electric current. Such, however, is not the real state of the case. The electric organ is always charged. It maybe conclusively shown by experiment that the action of that organ never ceases, and that round the body of a Torpedo, and probably of every other electric fish, there is a continual circulation of electricity in the liquid me- dium in which the animal is immersed. In fact, when the electric organ, or even a fragment of it, is removed from the living fish and placed between the ends of a galvanometer, the needle remains de- flected at a constant angle for twenty or thirty hours, or even longer. " I must here explain that in electro-physiological experiments it is highly advantageous to employ, as extremities of the galvanometer, plates of amalgamated zinc immersed in a neutral saturated solution of sulphate of zinc. This arrangement, which can be worked with the greatest facility, gives a perfectly homogeneous circuit, leaving the needle at zero in an instrument of 24,000 coils ; the liquid in contact with the animal part experimented on has the greatest pos- sible conductibility while it does not act chemically on the tissue, and the apparatus is entirely free from secondary polarity. " To return to the Torpedo. The electric organ, or a portion of it, detached from the fish and kept at the temperature of freezing, preserves its electromotive properties for four, six, or even eight days ; and an organ which has been kept for twenty-four hours in a vessel surrounded with a frigorific mixture of ice and salt, is found to possess an electromotive power as great as that of the organ recently detached from the living fish. Thus the electric organ retains its functional activity long after both muscular and nervous excitability have been extinguished. " What then is the action of the nerves on this apparatus ? Here again experiment affords a very distinct and conclusive answer. De- tach the organ of a live torpedo and cut it into two equal portions, in such a way as to leave each half in connexion with one of the large nervous trunks ; place the two halves on a plate of gutta percha, with electric couples opposed ; that is, with the similar surfaces (say the dorsal) in contact ; and connect the two free (ventral) surfaces with the extremities of the galvanometer. There will usually be no deflection of the needle, or, at most, a very slight effect which will 2 R2 578 soon disappear. Now, after having opened the circuit of the galva- nometer, irritate the nerve of one of the segments, by pinching, by the interrupted electric current, or in any other way ; or prick the piece itself with a needle. The portion of organ thus stimulated will give several discharges in succession, and a rheoscopic frog's limb with its nerve applied to the part will each time be thrown into vio- lent convulsions. If, after this, the galvanometer be applied as be- fore, there will be a very strong deflection in a direction answering to the segment stimulated. This deviation endures for a short time, but gradually becomes less, so that in a few minutes the effect of the two segments is equal. Stimulation now of the other segment will in like manner render its electricity predominant. These alterna- tions may be repeated several times, but naturally the effect becomes less and less marked. " Thus the electromotive apparatus becomes charged and acts in- dependently of the influence of the nerves, but that influence renews and renders persistent the activity of the apparatus. We know, moreover, that the discharge, which is only a state of temporary in- creased activity of the organ, is brought on by an act of the will in the live animal, or by the excitation of the nerves of the organ. " I shall not enter now into further details respecting my recent experiments on the Torpedo, but I venture to think that we have really made a step towards clearing up the theory of the animal elec- tromotive apparatus. The organ of the Torpedo does not, under the influence of the nerves, act as an induction apparatus ; the operation seems more analogous to that of a 'secondary pile,' created, through the influence of the nerves, in each constituent cell of the organ. " The case is very different in muscular action, the changes occur- ring in which are better understood now that we know the pheno- mena of muscular respiration. I do not here refer to the variation of the muscular current which takes place at the moment of con- traction. In that case it would appear from experiment, as I lately showed, that there are indications of a current in an opposite direc- tion ; but the conditions of the animal structure in action are so complex that no inference can be drawn as to the intimate nature of the phenomenon. It is otherwise, however, in comparing muscles which have been left at rest with muscles which have been fatigued by repeated contraction. Being still engaged in the investigation of 579 this matter, I shall content myself now with mentioning one result of my inquiry, which I consider as well established ; the result, in fact, of performing on muscles the same kind of experiment as the one above described on the organ of the Torpedo. The experiment is as follows : — Having selected a series of muscles, entire or divided, which have been proved (by my method of opposed muscular piles) to be equal in electromotive power ; subject a certain number of them to repeated stimulation, and then, by means of the method of opposed couples, compare the muscles which have been exercised with those which have been left at rest, and it will be found that the latter will manifest a much greater degree of electromotive power than the former. The nervous excitation, which causes muscular con- traction, developes heat, generates mechanical force and consumes . chemical affinity; and as the electromotive apparatus of muscle operates through means of that affinity, it must get weakened, like a pile in which the acid has become weaker. In the Torpedo, on the other hand, there is neither heat nor mechanical force produced, and the electromotive apparatus is set up again, as it were, through the influence of the nerves, after the manner of a secondary pile." V. " Natural History of the Purple of the Ancients." By M. LACAZE DUTHIERS, Professor of Zoology in the Faculty of Sciences of Lille. Communicated by Professor HUXLEY. Received March 22, 1860*. The purple dye so esteemed by the ancients has by turns excited the curiosity of naturalists and of historians. The number of memoirs upon the subject is considerable, and they are to be found in almost all tongues. However, in all these works, remarkable in many respects, and which cannot be analysed in this short notice, three deficiencies are to be noted regarding matters of very great moment in the history of this substance. What are, 1st, the producing organs? 2ndly, the nature? 3rdly, the natural primitive colour of the dye ? It is difficult to give any answer to these three questions by means of the facts contained in existing memoirs. It is for the purpose of replying to them that I * Translation received August 22, 1860. 580 have undertaken the investigation, whose chief results I have the honour now to lay before the scientific world. The two genera Murex and Purpura have yielded the species observed. In very distant localities, as at Mahon in Minorca, Murex brandaris, M. trunculus, and Purpura hcemastoma have furnished results which observations conducted at Boulogne on Purpura la- pilluSy at Pornic (Vendee) on the same species and Murex erinaceus, and at La Rochelle and L'lle de Rhe, have confirmed. At Marseilles, Murex brandaris has yielded altogether similar results ; and this concordance of all the observations permits me to offer them with much confidence. What is the organ which produces the dye ? The analogy which some chemists imagine they have found between the colour of alloxan or of murexide and the purple of the Mollusca, has led them to misconceive the nature of the organ which produces the colouring matter. It is indubitable that uric acid treated with nitric acid gives a beautiful reddish purple colour when the residue is exposed to ammoniacal vapour ; and this reaction furnishes a means of detecting the renal organ in mollusks. But from this circumstance no one could be justified in concluding that the purple dye was either the secretion of the kidney or the result of a modification of the urine. Careful dissection of the purpuriferous mollusca proves that the purple dye is secreted by a very limited portion of the mantle, which can in no way be confounded with the true renal organ, as which the organ of Bojanus is now generally regarded ; the position and the structure of the purpuriferous organ are indeed totally different from those of the kidney. Small in extent, this part occupies very nearly the space bounded by the branchiae and the rectum, beyond whose extremities it hardly extends anteriorly, while posteriorly it, at most, reaches the organ of Bojanus. It forms neither a sac nor a reservoir, as it has been stated to do j and these phrases, as well as ' purpuriferous vein,' should be rejected, because the organ is simply extended over the surface. Large elongated cells, placed perpendicularly side by side on the surface of the pallial cavity in the direction of its greatest diameter, compose its tissue. They form about two or three layers, the most 581 exterior of which, covered with vibratile cilia, presents the most developed cells. Below lies a very rich capillary network, which distributes the blood coming from the organ of Bojanus and the neighbouring parts of the mantle to the branchiae. The cells, when they have reached maturity, fall into the pallial cavity, become endosmotically distended, burst, and mingle their contents with the other mucus which already existed there. This independent and isolated shedding of the histological elements constitutes the secre- tion of the dye-stuff, which, it is obvious, is not produced by a com- pound gland, or indeed by any gland in the proper sense of the word, but by a glandular portion of the pallial surface. It is the granular but soluble matter contained in these cells which possesses singular properties, and constitutes the dye-stuff. The peculiar layer whose position has just been indicated is not special, anatomically speaking, to the two genera Murex and Pur- pura ; and this is important if, in looking at the matter morpholo- gically, a similar part of the surface of the mantle of most gaste- ropods appears to produce a substance of like histological character, but different in its properties. In the Aplysise and the Snails it is naturally coloured, whilst in Turbo littoralis and Trochus cinereus it is colourless, and undergoes no modification by the action of the solar rays. Thus, then, it is incorrect to say, with some chemists, that, ana- tomically speaking, the purple dye-stuff is yielded by the kidneys of Mollusca. Anatomical investigation has led to the recognition in the genera Murex and Pur pur a of a peculiar anal gland placed alongside the rectum, and opening by a terminal pore close to the anus. This gland, which does not seem to have been described hitherto, is in structure and the arborescent disposition of its secretory caeca, a well-defined gland ; and by this very circumstance it is impossible to confound it with the purpuriferous organ. Properties of the Purple Dye-stuff. — A very curious fact, known from all antiquity, since the very existence of the dye depends upon it, is the transformation of the dye-stuff by the action of the solar rays. In the living animal this substance is at first colourless, or more or less yellowish ; exposed to the light of the sun, in a moist state it acquires a pure violet hue ; in a word, it is photogenic. 582 The solar action causes the three simple colours to be developed successively, and in the following order, yellow, blue, and red. Between these, the compound colours green and violet which result from their mixture, are obtained with the greatest distinctness if the action is slow. But whilst the yellow disappears by prolonged action, a considerable amount of blue always remains ; whence in nature the final red is never pure, so that the dye always inclines more or less to violet. These properties have been placed beyond doubt by the possibility of making photographs on silk and cambric, which exhibit a remark- able delicacy in detail, combined with great strength of tone. In a photograph obtained in this way, the different tints through which the dye-stuff passes before becoming violet are more or less to be seen, but the deep violet predominates, and represents the black of ordinary photographs. The changes in the colour of the purple dye-stuff are accompanied by the production of a very penetrating foetid odour, similar to that of essence of garlic. The evolution of this odour is as charac- teristic of the solar action as the changes of colour, a consideration of much importance when we desire to solve the problem to which I now turn — What was the primitive colour of the purple stuffs of antiquity ? At first sight this question seems to be easily answered; but when one seeks for a precise signification of the word " purple," one soon becomes embarrassed. If we ask a painter, without telling him why, — Be so good as to paint the shade which you would give to a purple drapery in a historical painting — each painter to whom the request is made will give a different colour. This is the case because no one has an exact idea of the primitive colour, which has been gradually modified, and which has now become the red, almost scarlet, which many painters understand by the word purple. It is only by the interpretation of the phrases of the ancients, and com- paring them with direct observations, that one arrives at a solution of the difficulty, which would appear to be of great use to art. It is enough to remark that the purple colour exists only because it has been developed by the sun, in justification of the conclusion that the ancients must have been acquainted with this peculiarity, as also with that of the development of the characteristic foetid 583 odour. Pliny, moreover, speaks of both, and hence it cannot be doubted that the purple was produced formerly exactly as at present, unless we admit that the animals and their dye-stuff have changed, which would be an altogether gratuitous hypothesis. The conclusion to which we are driven then is this : the colour was produced formerly as at present, under the same conditions and with the same characters, so that it ought to have been similar to that which we now obtain. In simple and natural experiments the violet has never failed to appear, while pure red has always been absent. One is led to con- clude, therefore, that the natural and unmodified purple of the ancients was violet, as it is now ; for whoever discovered it must have made the experiment, as it has been so often repeated, on the sea-shore, by breaking a purpuriferous mollusk, and crushing its mantle on moist linen which is exposed to the sun. Pliny cites Cornelius Nepos, who states positively that at first the violet purple was esteemed ; and the passages of Plato and of Aristotle, which relate to the colour, lead to the same conclusion. However, it cannot be doubted that though the colour of purple stuffs was primitively violet, the requirements of taste and of fashion led to the variation of its shades. Thus some stuffs were dyed twice, to give them a richer and more vivid colour — the so-called 'purpurea dibapha.' The mixture of species also contributed to modify the hues. Murex trunculus gives an almost blue shade. The fishermen of Port Mahon told me that it always yielded that colour, and especially that it would give a fixed and permanent colour. On the contrary, Purpura hcemastoma (which they call f cor de fel ') was known to them as staining their linen very permanently and ineffaceably. It ought also to be recollected that when mineral colours replaced the animal matter of mollusks, the hue varied ; and though the term * purple' might be retained, it was easy to pass by degrees to the deep red which rises in the mind when we recollect the purple worn by cardinals. Perhaps also the manipulations to which the molluscan dye-stuff may have been subjected by the dyers, and of whose nature we know nothing, approximated the purple to the red, which Pliny compares to that of coagulated blood. But it remains none the less demonstrated, both by the passages 584 from ancient authors and by experiment, that the primitive and natural colour of the purple was formerly t as now, violet. Hence it would appear to be requisite for a painter to consider the epoch when the personages who are represented clothed in purple drapery lived, for the hue varied with the age. The properties of the purple dye-stuff also render intelligible one ground of the esteem in which the colour was held ; for, developed by the influence of light, it could not fade, like the red of cochineal for example, but must always have remained beautiful, even in the luminous and dazzling atmosphere of Italy and the East. It would be difficult, with the scanty materials we possess, to determine exactly the species employed by the ancients. Without doubt Pliny has indicated the two genera Murex and Purpura of the moderns by the names Purpura and Buccinum. It is probable that Murex trunculus and brandaris, and Purpura hcemastoma, were employed by the dyers ; but it would be difficult to identify the dif- ferent species indicated by Pliny. Zoological investigations, accom- panied by experiments which are all simply and easily made, would perhaps lead to results more definite than can be obtained by the in- terpretation of passages, if one could carry them oat on the shores of countries formerly famous for their purple — those of Tyre for example. Fig. 1. Fig. 2. Fig. 1. Animal with Purpura lapillus, with the pallial cavity laid open. 1. Genital orifice. 3. Anal gland. 5. Branchiae. 2. Anus. 4. Purpurogenic organ. 6. Organ of Bojanus. Fig. 2. The animal simply removed from its shell. 1. Branchiae. 2. Purpurogenic organ. 3. Anal gland. 585 VI. " Contributions towards the History of Azobenzol and Ben- zidine." By P. W. HOFMANN, Ph.D. Communicated by Dr. HOFMANN. Received July 24, 1860. Among the numerous compounds into which benzol, when sub- mitted to reagents, is converted, azobenzol and its derivatives have as yet received but limited attention. Although more than twenty- five years have elapsed since this interesting body was discovered by Mitscherlich, both its formation and its constitution remain still doubtful. Mitscherlich*, who discovered azobenzol in 1834, when submitting nitrobenzol to the action of an alcoholic solution of potassa, repre- sented this compound by the formula C6H5Nf, but left the reaction which gives rise to the formation of azobenzol unexplained. In 1845 this body was reprepared by Hofmann and Muspratt^, who observed among the collateral products of the reac- tion aniline and oxalic acid. They represent the formation of azobenzol by the equation 2C6H5N02+C2H60=C6H5N + C6H7N-fC2H204+HaO, Nitrobenzol. Alcohol. Azobenzol. Phenylamine. Oxalic acid, adding at the same time that they are far from considering this equation as more than the representation of one phase of the trans- formation of nitrobenzol, since several other rather indefinite com- pounds or products are formed simultaneously. At about the same period Zinin made the interesting observation that azobenzol is capable of fixing hydrogen and of being thereby converted into a well-defined base, benzidine, which he represented by the formula C9H,N. Considering the physical characters both of azobenzol and of ben- zidine, especially the high boiling-points of these substances, and the ratio of hydrogen and nitrogen in the latter compound, the sum of * Pogg. Ann. xxxii. p. 224. f H = l,0 = 16, C = 12, &c. J Mem. of the Chem. Soc. vol. iii. p. 113. 586 the number of equivalents of these two elements not being divisible by 2, many chemists were inclined to double the formulae of both bodies, and to represent them by the following expressions : — Azobenzol C12 H10 N2 Benzidine C12H12N2 This view received the first experimental confirmation in the forma- tion of the nitro-derivatives of azobenzol, which were examined in 1849 by Gerhardt and Laurent. The formation of Nitrazobenzol .... C12 H9 N3 O2=C12 (H9 NO2) N2, of Dinitrazobenzol . . C12 H8 N4 O4=C12 [H8 (NO2)J N2, and of several derivatives of these bodies, having established the C12-formula of azobenzol, but little doubt could be entertained re- garding the formula of berizidine, which is as readily obtained from azobenzol by reducing agents, as it may be reconverted into azobenzol by nitric acid*. The molecular value of benzidine being thus almost exclusively fixed by the determination of the formula of the compound from which it originates, it was of some interest to obtain additional experi- mental evidence for the molecular weight of azobenzol. With this view I have determined the vapour- density of azoben- zol. This body boiling at a rather high temperature, I have availed myself of the method of displacement lately proposed by Professor Hofmann. Experiment proved the density of the azobenzol-vapour to be 94 referred to hydrogen as unity, or 6'50 referred to air. The theoretical vapour-density of azobenzol, assuming that one molecule of this compound furnishes, like the rest of well-examined sub- 1 82 stances, 2 vols. of vapour f, is = 91 referred to hydrogen, and 6-32 referred to air. The determination of the vapour-density, then, plainly confirms the higher molecular weights proposed for azobenzol and for benzidine. When determining the vapour-density of azobenzol, I had occasion to observe that, probably in consequence of a typographical error, the boiling-point of this compound is misstated in all the manuals which I could consult, and even in the original memoirs of Mit- scherlich himself. The boiling-point is stated to be 193° C., whilst it is in reality 293° C. * Noble, Journal of the Chem. Soc. vol. viii. p. 293, f H20 = 2 vols. 587 Benzidine, when expressed by the formula C12H12N2, presents itself as a well-defined diacid diamine. The molecular con- struction of the diatomic base remained to be decided. I have endeavoured to solve this problem by the process of ethylation, as yet the simplest and the best guide in determining questions of this kind. Benzidine in the presence of alcohol is rapidly attacked by iodide of ethyl. After two hours' digestion at 100° C. in sealed tubes, the reaction is complete. The solution on evaporation yields a crystalline iodide, C16H22N2I2=C12H,2(C2H8)2N2I2, from which ammonia separates a solid crystalline base very similar to benzidine. This compound, which fuses at 65° C., and resolidi- fies at 60° C., is diethylbenzidine : CieH20N2=C,3H10(CaHs)2N2> which forms well-crystallizable salts with the acids, and yields with dichloride of platinum a difficultly soluble crystalline platinum- salt containing C16 H22 N2 C12 2PtCl2. When diethylbenzidine is treated again with iodide of ethyl, the phenomena previously observed repeat themselves. The iodide C20H30N2I2=C12H10(C2H5)4N2I2 is formed, which when decomposed by ammonia yields tetrethyl- lenMine C20H28N2=C12H8 (C2H5)4N, Tetrethylbenzidine resembles the diethylated and the non-ethylated base. It fuses at 85° C., resolidifying at 80° C., produces with the acids crystalline compounds, and furnishes with dichloride of plati- num a platinum-salt of the formula C20H30N2Cl2,2PtCl2. The further action of iodide of ethyl upon tetrethylbenzidine is extremely slow. After 12 hours' digestion at 100° C. only a very minute quantity of the base had been transformed into an iodide. Iodide of methyl, on the other hand, acts with great energy. An hour's digestion is sufficient to produce the final diammonium-com- pound. The iodide C22 H34 N2 12=C12 H8 (C2 H5)4 (CH3)2 N2 12 is very difficultly soluble in absolute alcohol, but dissolves with facility in boiling water, from which it is deposited on cooling, in 588 long beautiful needles. The solution of this iodide is no longer pre- cipitated by ammonia, but yields with oxide of silver a powerfully alkaline solution, exhibiting all the characters of the completely sub- stituted ammonium- and diammonium-bases discovered by Professor Hofmann. The solution of this dimethyl-tetrethylated base, which contains TT M Q _^12 AA8 V^2 -"5/4 WAX3>'2 ^2 1 f) ^U361>I2U2- HJU2' is not further acted upon by either iodide of ethyl or methyl. With acids it forms a series of salts which are remarkable for the beauty with which they crystallize. The platinum-salt is almost in- soluble in water, but soluble with difficulty in concentrated boiling hydrochloric acid, crystallizing from this solution on cooling in beautiful needles. This salt contains C22H34N2Cl2,2PtCl2. The above experiments appear to establish the molecular construction of benzidine in a satisfactory manner. This base is obviously a primary diamine, in which the molecular group C12 H8, whatever its nature may be, functions as a diatomic radical. A glance at the subjoined Table exhibits the construction of benzidine and of the several compounds which I have described. Diamines. (C12H8)" Benzidine H2 J- N2, Diethylated ben- zidine . (CiaH8)"l taid k, (H2)2 J 'n" Tetrethylated (C12 benzidine .... (C, Iodides of Diammoniums. Primary [(C12H8)» H6 N2]"I2> Secondary .... [(CJ2 H8)» H4 (C, H5)2 NJ» I2> Tertiary [(C12H,)" H2 (C^XNJ'I,, Quartary [(C12 H.)» (CH3)2 (G, H5)4 NJ» I2. The experiments described in this note were performed in Pro- fessor Hofmann' s laboratory. 589 VII. " On Bromphenylamine and Chlorphenylamine." By E. T. MILLS. Communicated by Dr. HOFMANN. Received July 24, 1860. Nitrophenylamine, when prepared from dinitrobenzol (i. e. by tbe indirect method), differs in so many respects from the isomeric base which is obtained from phenyl-compounds (i. e. by the direct method), that chemists have distinguished these two bodies as alpha- and beta-nitrophenylamine * — Bromphenylamine and chlorphenylamine have hitherto been produced only by the action of potash upon bromisatin and chorisatin, the indirect method, by which they were originally obtained by Dr. Hofmann ; it appeared therefore of some interest to ascertain whether the bodies generated directly from * The alpha-nitrophenylamine (nitraniline) was formed about sixteen years ago by Dr. Muspratt and myself (Chem. Soc. Mem. vol. iii. p. 112), by the action of reducing agents on dinitrobenzol. The beta-nitraniline was discovered by Arppe (Chem. Soc. vol. viii. p. 175), who obtained this compound when distilling pyrO- tartronitrophenylamide with potash. The two bases resemble each other in a remarkable manner; but there are differences in their physical and chemical characters which leave no doubt as to the fact of their having different constitu- tions. I may here remark that I have repeated Arppe's experiments, the results of which I can confirm in every particular. Since the phenyl-compound from which Arppe obtained his substance is accessible only with difficulty, I have endeavoured to nitronate a more easily procurable phenyl- compound. Acetyl- phenylamide may be used for this purpose with considerable advantage. A solution of the compound in cold fuming nitric acid yields, on the addition of water, a crystalline difficultly soluble precipitate, which is easily obtained pure by recrystal- lization. This substance contains [C6(H4N02)]-| C3H8N204=(C2 H3 02) U, H J and yields, when heated with potassa, the beta-nitrophenylamine of Arppe with all its properties. I may here recall a former observation, which has now become perfectly intelligible. When studying the action of nitric acid upon melaniline, I found (Chem. Soc. Mem. t. i. 305) that the dinitromelaniline, which is thus formed, essentially differs from the dinitromelaniline obtained by submitting nitrophenylamine (alpha-) to the action of chloride of cyanogen. The two nitro- bases, which are both expressed by the formula C13HnN504=C13[Hn(N02)2]N3, stand to each other in the same relation which obtains between alpha-nitro- phenylamine and beta-nitrophenylamine. In fact, I have since found that the distillation of the nitro-base, obtained by treating alpha-nitrophenylamine with chloride of cyanogen, furnishes alpha-nitrophenylamine ; whilst beta-nitrophenyl- amine maybe detected amongst the products of the distillation of the dinitromel- aniline which is formed directly from melaniline by means of nitric acid. — A. W. H. 590 compounds of phenylamine would exhibit differences in their proper- ties similar to those which distinguish alpha- and beta-nitrophenyl- amine. With the view of deciding this question experimentally, I have submitted acetylphenylamide to the action of bromine and chlorine, in the hope of thus forming directly from phenylamine the bromi- nated and chlorinated compounds in question. Action of Bromine on Acetylphenylamide. A cold aqueous solution of acetylphenylamide, when agitated with bromine gradually added in small quantities until the yellow colour imparted to the liquid no longer disappears, furnishes a crystalline compound difficultly soluble in cold, but easily recrystallizable from boiling water. The substance consists chiefly of monobrominated acetylphenylamide (C6H4Br) (C8H3BrNO=(C2H30) N, which is however invariably mixed with small quantities of dibro- minated acetylphenylamide (C6 H3 Br2) } (C8H7Br2NO=(C2H30) I N. T have not been able to find a method of separating these two bodies perfectly. The brominated compound is readily attacked by potash. On distilling the mixture, the vapour of water carries over a volatile body which solidifies in the condenser into beautiful acicular crystals, acetate of potassium remaining in the retort. The solidified distillate was purified by recrystallization from boil- ing water, and submitted to analysis. Both the combustion of the base itself and the platinum-determination of the beautiful golden- yellow platinum-salt proved this body to be bromphenylamine (C6H4Br) C6H6BrN= H N. In its appearance, odour, and taste, as likewise in its deportment with acids and with solvents generally, the brominated base ob- tained from acetylbromophenylamide resembles perfectly the brom- phenylamine produced from bromisatin, a specimen of which I ob- 591 tained from Dr. Hofmann's collection. There is only one point in which a slight difference was observed. Both compounds are capable of crystallizing either in needles or in well-defined octahedra, the former being generally obtained from water, and the latter from alcohol. The bromphenylarnine, obtained from the acetyl-compound, appears to be more inclined to crystallize in needles than in octa- hedra. Circumstances have prevented me from entering into an examination of the products of decomposition of the two brom- phenylamines ; and the question whether these two bodies are really identical, or similarly related as the two nitro-compounds, must be decided by further experiments*. Action of Chlorine on Acetylphenylamide. The phenomena observed in the action of chlorine on a cold saturated solution of the phenyl-compound are perfectly similar to those presented in the corresponding reaction with bromine. A crystalline compound immediately separates from the solution; as soon as the crystals cease to augment, the current of chlorine is inter- rupted. Washed with cold, and once recrystallized from boiling water, the chlorinated body is found to be nearly perfectly pure monochlorinated acetylphenylamide c6H4c C8H8C1NO=C2H30 N, which, when distilled with potash, furnishes abundance of chlor- phenylamine, resembling in a marked manner the chlorphenylamine obtained by the action of potash upon chlorisatin. VIII. " New Compounds produced by the substitution of Ni- trogen for Hydrogen." By P. GRIESS. Communicated by Dr. HOFMANN. Received July 24, 1860. In several previous notes I have called attention to a peculiar double acid which is formed by the action of nitrous acid upon ami- dobenzoic acid, C14 H14 N2 04 + II NOa=C14 Hn N3 O4+ 2H2 Of, * These experiments have since been made by Mr. P. Griess, whose results are given in the next abstract. — A. W. H. f 11 = 1 ; O = 16; C = 12, &c. VOL. X. 2s 592 the constitution of which, as far as my experiments go, may be re- presented hy the formula [C7 (H, N,0 O] [C, (H4, H3 N)0] 1 •ifiT There are not less than three other compounds known which em- pirically may he represented by the same formula as amidobenzoic acid, viz. nitrotoluol, salicylamide, and anthranilic acid. The two former substances differ from amidobenzoic acid both physically and chemically in a marked manner ; anthranilic acid, on the other hand, is so closely allied to the benzoic derivative, that special experiments were required to distinguish these two bodies. Gerland, when he submitted the two acids to Piria's well-known reaction, observed that both are converted by nitrous acid into non-nitrogenated acids, which, although still isomeric, essentially differ in their properties ; amido- benzoic acid being transformed into a new acid, — oxybenzoic acid, whilst anthranilic acid yields salicylic acid. It appeared of some interest to try whether the substitution of ni- trogen for hydrogen in anthranilic acid would furnish a compound isomeric with the double acid obtained from amidobenzoic acid. A current of nitrous acid, when passed into a cold alcoholic solution of anthranilic acid, rapidly transforms this substance into a compound crystallizing in white prisms, which is easily obtained by allowing the alcohol to evaporate at the common temperature. The new body is extremely soluble in water, insoluble in ether. By analysis it was proved to contain r TT IV n ^u -^-a ™« "r The new compound is thus seen to be far from isomeric with the derivative of amidobenzoic acid produced under similar circumstances, with which, in fact, it shows no analogy whatever. I have not yet arrived at a definite view regarding the molecular construction of this body ; nevertheless its deportment with water shows even now that the nitrogen in it exists in two different forms. Gently heated with water, the new compound disengages torrents of nitrogen ; on cooling, the liquid solidifies into a crystalline mass of salicylic acid, free nitric acid remaining in solution. This metamorphosis is repre- sented by the equation C14H9N50,H-2HiO=N44-HN03-|-2C7H603, New body. Salicylic acid. 593 which has been controlled by quantitative experiments. The idea suggests itself to assume one-fifth of the nitrogen in the form of nitric acid, when the new body might be viewed as a salt-like compound of the formula C7H4N2'OJ C7H4N2'OJ the action of the water consisting simply in the replacement of the monatomic nitrogen by the elements of water, which would produce salicylic acid, nitric acid being liberated. I avail myself of this opportunity of mentioning the deportment of several other isomeric bodies under the influence of nitrous acid. There are two basic compounds, C6(H6N02)N, known ; the one is the alphaphenylamine of Hofmann and Muspratt, the other the betaphenylamine observed by Arppe. When submitted to the action of nitrous acid, these two isomeric bodies yield two perfectly different nitrogen-substituted derivatives. The substance obtained from alphaphenylamine (the base formed by the reduction of dinitrobenzol) has been already mentioned in one of my previous notes, the body derived from betaphenylamine is still under exami- nation. The action of nitrous acid proves that there are also two bromphe- nylamines similar to the two nitrophenylamines. The original brom- phenylamine discovered by Hofmann, and which is formed by the di- stillation of bromisatin with hydrated potash, yields with nitrous acid a compound, C12H9Br2N3= N'" N2, H crystallizing in beautiful golden-yellow needles, insoluble in water, and difficultly soluble in alcohol and ether. The bromphenylamine, on the other hand, which was lately prepared by Mills * from acetyl- bromphenylamide, exhibits with nitrous acid a perfectly different deportment, being transformed into a yellow scarcely crystalline com- pound, easily soluble in alcohol and ether, but insoluble in water. I have not as yet analysed this compound ; its formation, however, * See the previous abstract. 2 s 2 594 and its properties render it probable that it will be found to be iso- meric with the product of decomposition previously mentioned. I am engaged in a more minute examination of this compound, which I hope may assist in explaining the cause of the still enigmatical iso- merism exhibited by the derivatives of phenylamine. I have already repeatedly called attention to the different atomicity exhibited by nitrogen under different conditions. Tn the derivatives of amidobenzoic and of anthranilic acids, it can be proved that 1 equiv. of nitrogen replaces 1 equiv. of hydrogen ; while in the derivatives of phenylamine, the nitrogen is present with the value of three molecules of hydrogen. The experiments which I have described were performed in Dr. Hofmann's laboratory. IX. " Contributions towards the History of the Monarchies." — No. III. Compound Ammonias by Inverse Substitution. By A. W. HOFMANN, LL.D., F.R.S., &c. Received July 24, 1860. Many years ago I showed that the bromide or iodide of a quartary ammonium splits under the influence of heat into the bromide or iodide of an alcohol-radical on the one hand, and a tertiary moriamine on the other. Having lately returned to the study of this class of substances, I was led to examine the deportment, under the influence of heat, of the tertiary, secondary, and, lastly, of the primary monammonium- salts. Experiment has shown that these substances undergo an ana- logous decomposition. The chloride of a tertiary monammonium when submitted to distillation yields, together with the chloride of an alcohol-radical, a secondary monamine ; the chloride of a secondary monammonium, together with an alcohol-chloride, a primary mona- mine ; lastly, the chloride of a primary monammonium, the chloride of an alcohol-radical and ammonia. Exactly, then, as my former experiments show that we may rise in the scale by replacing the four equivalents of hydrogen in ammonium one by one by radicals, so it is obvious from these new experiments 595 that we may also step by step descend, by substituting again hy- drogen for the radicals in succession. To take as an illustration the monammonium-salts of the ethyl- series which as yet I have chiefly examined : Ascent. H3N+ (C2H5)Br = [(C, H,) H3 N] Br Ammonia. Bromide of ethyl. Bromide of Ethylammoriium. (C, H5) H2 N + (C2 H5) Br =, [(C, H5)2 H2 N] Br Ethylamine. (C2H5)2HN + Diethylamine. Triethylamine. Bromide of Diethylainmonium. (C2H5)Br = [(C2H5) HN]Br Bromide of Triethylammonium. (C3H5)Br = [(C.B,X N]Br Bromide of Tetrethylammonium. Note.— H = l; C = [(C2H5)4 N]C1 Descent, = (C2H5)C1 + (C2H5)a N Chloride of Tetrethylammonium. Chloride of Ethyl. [(C2H5)3H N]C1 = Chloride of Triethylammonium. [(C2H5)2H2N]C1 = Chloride of Diethylammonium. [(C.H.) H3N]C1 = Chloride of Ethylammonium. (C2H5)C1 + (C2H5)C1 + (0,HB)C1 + Triethylamine. (C,H,),H N Diethylamine. (C2H6)H2N x ____^f Ethylamine. ^N Ammonia. The above reactions, interesting when regarded from a scientific point of view, admit of but limited application in practice. The purity of the result is disturbed by several circumstances, which it is difficult to exclude. Unless the temperature be sufficiently high, a small portion of the ammonium-salt submitted to distillation sublimes without change ; again, a portion of the same salt is repro- duced in the neck of the retort and in the receiver*, from the very constituents into which it splits ; lastly, if the temperature be too high, the chloride of ethyl is apt to be decomposed into ethylene * This inconvenience may be partly obviated by distilling into an acid. 596 and hydrochloric acid, the latter producing, with the monamine liberated in the reaction, a salt which in its turn is likewise decom- posed. Thus the chloride of diethylammonium, for instance, together with chloride of ethyl and ethylamine, yields ethylene and chloride of ethylammonium which splits into chloride of ethyl and ammonia. The idea naturally suggested itself, to attempt, by means of this reaction, the formation of the primary and secondary monophosphines, which are at present unknown. Experiments made with the view of transforming triethylphosphine into diethylphosphine have as yet remained unsuccessful, the chloride of triethylphosphonium distilling without alteration. X. " Notes of Researches on the Polyammonias." — No. IX. Remarks on anomalous Vapour-densities. By A. W. HOF- MANN, LL.D., F.R.S. Received July 24, 1860. In a note addressed to the Royal Society * at the commencement of this year, I have shown that the molecules of the diamines, like those of all other well- examined compounds, correspond to two volumes of vapour f, and I have endeavoured to explain the apparent anomalous vapour-densities of the hydrated diamines by assuming that the vapour-volume experimentally obtained was a mixture of the vapour of the anhydrous base and of the vapour of water. Thus, hydrated ethylene-diamine was assumed to split under the influence of heat into anhydrous ethylene-diamine (2 vols. of vapour) and water (2 vols. of vapour). (C2H4)" H " The vapour-density of ethylene-diamine referred to hydrogen being 30, and that of water vapour 9, the vapour-density of a mixture of equal volumes of ethylene-diamine and water- vapour = — - — = 19*5, which closely agrees with the result of experiment. In continuing the study of the diamines, I have expanded these C2H10N20= H2 * Proceedings, vol. x. p. 224. f Ha 0 = 2 vols. J H = l; 0 = 16; C = 12, &c. 597 experiments. Without going into the detail of the inquiry, I beg leave to record an observation which appears to furnish an experi- mental solution to the question. Ethylene-diamine, when submitted to the action of iodide of ethyl, yields a series of ethylated derivatives, amongst which the diethylated compound has claimed my particular attention. This body in the anhydrous state is an oily liquid containing (C.HJ"] C6H16N2 = (C2H5)2lN2. H2 J With water it forms a beautiful crystalline very stable hydrate*, of the composition (C, HJ" C6H18N20=(C2H5)2 *12 The vapour- density of the anhydrous base was found by experi- ment to be 57*61, showing that the molecule of diethyl-ethylene- diamine corresponds to 2 vols. of vapour, the theoretical density being 111=57. On submitting the crystalline hydrate to experiment, I arrived at the vapour-density 33 '2. This number is in perfect accordance with the result obtained in the case of ethylene-diamine. The legitimate interpretation of this number is that here again the hydrated base splits into the anhydrous diamine and water, and that the density observed is that of a mixture of equal volumes of diamine-vapour and of water-vapour, the theoretical density of which is — - — =33. A The correctness of this interpretation admits of an elegant experi- mental demonstration. Having observed that the hydrate loses its water when repeatedly distilled with a large excess of anhydrous baryta, the idea suggested itself, to attempt the decomposition of the hydrate in the state of vapour. If the vapour obtained by heating this hydrate to a tem- perature 1 5° or 20° higher than its boiling-point actually consisted of a mixture of equal volumes of its two proximate constituents in a state of dissociation (to use a happy term proposed by Deville), it appeared very probable that the volume would be halved by the * Proceedings, vol. x. p. 104. Experiment has verified this 598 introduction of anhydrous baryta, anticipation. The upper half of a glass tube filled with, and inverted over, mer- cury, was surrounded by a second glass tube open at both ends and of a diameter about treble that of the former, the annular space between the two being closed at the bottom of the outer tube by a well-fitting cork. The vessel thus formed round the upper part of the inner tube was moreover provided with a small bent copper tube open at the top and closed at the bottom, which was likewise fixed in the cork. The vessel being filled with paraffin and a lamp being applied t6 the copper tube, the upper part of the mercury-tube could be- conveniently kept at a high and constant temperature, whilst the lower end, immersed in the mercury-trough, remained accessible. A glance at the figure explains the disposition of the apparatus. A small quan- tity of the hydrated base was then allowed to rise on the top of the mercury in the tube; and the paraffin bath having been heated to 170°, the volume of the vapour was observed. Several pellets of anhydrous baryta were then allowed to ascend into the vapour- volume, while the temperature was maintained constant. The mer- cury began immediately to rise, becoming stationary again, when a fraction of the vapour had disappeared, which amounted, the neces- sary corrections being made, to half the original volume. XL " Notes of Researches on the Poly- Ammonias." — No. X. On Sulphamidobenzamine, a new base ; and some Re- marks upon Ureas and so-called Ureas. By A. W. HOF- MANN, LL.D., F.R.S. Received July 24, 1860. Among the numerous compounds capable of the metamorphosis involved in Zinin's beautiful reaction, the nitriles have hitherto 599 escaped the attention of chemists. This is the more remarkable, since some of these bodies are easily converted into crystalline nitro-compounds . When examining several of the diamines which I have lately submitted to the Royal Society *, I was induced to study the trans- formation which benzonitrile undergoes under the successive influ- ence of nitric acid and reducing agents. Benzonitrile, when treated with a mixture of sulphuric and fuming nitric acid, furnishes, as is well known, a solid nitro-substitute which crystallizes from alcohol in beautiful white needles, containing C7H4N202=C7(H4,N02)Nf. In order to obtain this body, it is desirable to perform the opera- tion with small quantities, and to cool the liquid carefully, otherwise the formation of appreciable proportions of nitrobenzoic acid can scarcely be avoided. The nitro-compound is readily attacked by an aqueous solution of sulphide of ammonium ; sulphur is abundantly precipitated, and on evaporating the liquid, a yellowish red oil is separated, which gradually and imperfectly solidifies. This substance possesses the characters of a weak base, dissolving with facility in acids, and being again precipitated by the addition of ammonia and the alkalies. The preparation in the state of purity, both of the base itself and of its compounds, presents some difficulty. This circumstance has pre- vented me from analysing the base. I have, however, examined one of its products of decomposition, which leaves no doubt that nitro- benzonitrile, under the influence of reducing agents, undergoes the well-known transformation of nitro-compounds, and that the com- position of the oily base is represented by the formula C7H6N2=C7H4(NH2)N. The oily base, when left in contact with sulphide of ammonium, is gradually changed, a crystalline compound being formed, which is easily soluble in alcohol and in ether, but difficultly soluble in water, and which may be purified by several crystallizations from boiling water, being deposited on cooling in white brilliant needles. This compound is a well-defined organic base ; it dissolves with facility in acids, and is precipitated from these solutions by the addition * Proceedings, vol. x. p. 104. f H = l; 0 = 16; C = 12, &c. 600 of potassa or of ammonia. With hydrochloric acid it forms a cry- stallizable salt, which yields, with dichloride of platinum, an orange - yellow crystalline precipitate. On analysis, the new base was found to have the composition C7H8N2S, explaining its formation, in which evidently two phases have to be distinguished : (1) C7(H4N02)N + 3H2S=2H20 + 3S + C7H6N2, (2) C7H6N2 + H2S=C7H8N2S. The new sulphuretted base has the same composition as sulpho- carbonyl-phenyldiamide, a feebly basic compound which I obtained some time ago by the action of ammonia on sulphocyanide of phenyl*. A superficial comparison of the properties of the two bodies shows, however, that they are only isomeric, the constitution of the latter compound being represented by the expression (C S)" (C6H6)'lN2 whilst the constitution of the former may be expressed by the formula H Ha The new sulphuretted base is closely connected with an interesting compound which Chancel obtained some years ago, when he submitted nitrobenzamide to the action of reducing agents. The crystalline base produced in this reaction contains C7H8N20, and differs from the body which forms the subject of this note only by having oxygen in the place of sulphur. The formation of this oxygenated compound has given rise to some misconceptions, which I take this opportunity to elucidate. A short time before the discovery of the body in question, I had obtained a compound of exactly the same composition by the action of the vapour of cyanic acid upon aniline, C6H7N + CHNO=C7H8N20. The mode of producing this substance pointed it out as an ana- * Proceedings, vol. ix. p. 276. 601 logue of urea, and hence the designation aniline-urea, under which I described the new body as the first of the group of compound ureas, which has since been so remarkably enriched by Wurtz and several other chemists. The aniline-urea, or phenyl-urea as it is more appropriately called, diifers from ordinary urea in its deportment with acids, being, in fact, no longer capable of producing saline compounds. The absence of basic properties in the new phenyl-compound was sufficient to throw some doubt upon its ureic character, and this doubt appeared to receive additional support by Chancel's subsequent discovery of a compound possessing not only the composition of phenyl-urea, but forming likewise well-defined saline combinations. This compound is, however, the amide of amidobenzoic acid, its constitution being interpreted by Chancel, in accordance with its formation : c7H5cn Benzamide H V N. H I C7(H4N02)01 Nitrobenzamide V N. C,(H. Amidobenzamide H H Nevertheless chemists, by silent but general consent, began to look upon this compound as the true phenyl-urea ; and in most manuals, even Gerhardt's 'Traite de Chimie' not excepted, it figures under this appellation. Let us see how far this view is supported by the deportment of this substance. Compound ureas, as I conceive the character of this class, must imitate the deportment of urea par excellence, both in their mode of formation and their products of decomposition. Urea is formed whenever cyanic acid or cyanates come in contact with ammonia or ammoniacal salts. These are precisely the conditions under which the substance which I have described as phenyl-urea is generated. This compound is obtained by the union of cyanic acid with phenylamine, or of ammonia with cyanate of phenyl. CCHS 602 H N. On the other hand, no cyanogen-compound is involved in the formation of amidobenzamide, or amidobenzamine, as it might be more appropriately called, on account of its basic properties. Not less decisive is the evidence furnished by the products of decomposition of the two bodies. The most characteristic trans- formation of urea is its decomposition into ammonia and carbonic acid when it is submitted to the action of the alkalies. A compound urea thus treated should yield, together with carbonic acid and ammonia, the monamine from which it has arisen. Phenyl-urea should furnish carbonic acid, ammonia, and phenylamine : these are precisely the products observed in the decomposition of the com- pound which is formed by the action of cyanic acid on phenylamine. (CO)"] H, H] C6H5 N. H3 H H Amidobenzamine, on the other hand, exhibits with potassa the deportment of an amidated amide. The reaction presents two di- stinct phases, ammonia and amidobenzoic acid being formed in the first phase, and ammonia and benzoic acid in the second : C7(H4H2N)O) TT, H Tl H LN+E}O=H H H H No trace of carbonic acid and no trace of phenylamine are elimi- minated by potassa. It is only by fusing with soda-lime that a perfect destruction of the compound ensues, when, as Chancel has distinctly observed, in the first place ammonia, and ultimately car- bonic acid and phenylamine are evolved. "What I have said respecting phenyl-urea applies with equal force to diphenyl-urea. Gerhardt describes as diphenyl-urea the com- pound obtained by Laurent and Chancel when they examined the action of reducing agents upon nitrobenzophenone, and which, on account of its yellow colour, was originally described as flavine. This body contains C H N O 603 which is certainly the formula of diphenyl-urea. But here again chemists have been misled by the basic properties of the substance, It is not my object at present to dwell on the constitution of flavine, which I intend to examine in a subsequent note ; suffice it to say that this substance is not diphenyl-urea. The true diphenyl-urea is the substance commonly called carbani- lide, or carbophenylamide. (CO)"-] C13H12N20=(<;6H5)2>N2. H2 J Both the conditions under which this body forms, and the pro- ducts into which it is decomposed, leave no doubt regarding its position in the system. This compound is formed by the action of cyauate of phenyl upon either water or phenylamine. r frov i lm (CO)" 2 |_(b. H5) } N J +fi } 0=(CO)"0 + CHs)2 N2, (CO)" When boiled with potassa, it splits into carbonic acid and phenyl- amine. rc6H^ -i H U . L H J J (C6HS)2 VN2 + VO=(CO)"0 + 2 H2 J J These are the characters of true diphenyl-urea. XII. " Researches on the Phosphorus-Bases." — No. VIII. Oxide of Triethylphosphine. By A. W. HOFMANN, LL.D., F.R.S. Received July 24, 1860. In our former experiments *, Cahours and myself had often observed this substance, but we did not succeed in obtaining it in a state of purity fit for analysis. Nevertheless, founding our conclu- sion on the composition of the corresponding sulphur-compound, and having regard to the analogies presented by the corresponding * Phil. Trans. 1857, p. 575. 604 terms of the arsenic- and antimony-series, we designated this body as the oxide of the phosphorus-base C6H15PO=(C2H5)3PO*. I have since confirmed this formula by actual analysis. The difficulties which in our former experiments opposed the preparation of this compound in the pure state, arose entirely from the comparatively small quantity of material with which we had to work. Nothing is easier than to obtain the oxide in a state of purity, provided the available quantity of material is sufficient for distillation. In the course of a number of preparations of triethyl- phosphine for new experiments, a considerable quantity of the oxide had accumulated in the residues left after distilling the zinc- chloride-compound with potash. On subjecting these residues to distillation in a copper retort, a considerable quantity of the oxide passed over with the aqueous vapours, and a further quantity was obtained, as a tolerably anhydrous but strongly coloured liquid, by dry distillation of the solid cake of salts which remained after all the water had passed over. The watery distillate was evaporated on the water-bath as far as practicable, with or without addition of hydro- chloric acid ; and the concentrated solution was mixed with solid hydrate of potassium, which immediately separated the oxide in the form of an oily layer floating on the surface of the potash. The united products were then left in contact with solid potash for twenty-four hours and again distilled. The first portion of the distillate still contained traces of water and a thin superficial layer of triethylphosphine. As soon as the distillate solidified, the receiver was charged, and the remaining portion — about nine-tenths — collected separately as the pure product. To prevent absorption of water, the quantity required for analysis was taken during the distillation. With reference to the properties of oxide of triethylphosphine, I may add the following statements to the description formerly given f. This substance crystallizes in beautiful needles, which, if an appreciable quantity of the fused compound be allowed to cool slowly, frequently acquire the length of several inches. I have been unable to obtain well-formed crystals ; as yet I have not found a solvent from which * H = 1 ; 0 = 16 ; C = 12, &c. t Phil. Trans. 1857, p. 575. 605 this substance could be crystallized. It is soluble in all proportions, both in water and alcohol, and separates from these solvents on evaporation in the liquid condition, solidifying only after every trace of water or alcohol is expelled. Addition of ether to the alcoholic solution precipitates this body likewise as a liquid. The fusing- point of oxide of triethylphosphine is 44° ; the point of solidification at the same temperature. It boils at 240° (corr.). As no determination of the vapour-density of any member of the group of compounds to which oxide of triethylphosphine belongs has yet been made, it appeared to me of some interest to perform this experiment with the oxide in question. As the quantity of material at my disposal was scarcely sufficient for the determination by Dumas' s method, and Gay-Lussac's was inapplicable on account of the high boiling-point of the compound, I adopted a modifica- tion of the latter, consisting essentially in generating, the vapour in the closed arm of a U-shaped tube immersed in a copper vessel containing heated paraffin, and calculating its volume from the weight of the mercury driven out of the other arm. Since I intend to publish a full description of this method, which promises to be very useful in certain cases, I shall here content myself with stating the results obtained in one of the experiments. Substance 0-150 grm. Volume of vapour 49' 1 cub. cent. Temperature (corrected) 266'6 Barometer at 0° 07670 metre. Additional mercury column at 0° 0'1056 „ These numbers prove the vapour-density of oxide of triethyl- phosphine to be 66*30, referred to hydrogen as unity, or 4'60 re- ferred to atmospheric air. Assuming that the molecule of oxide of triethylphosphine corresponds to 2 volumes of vapour*, the spec, grav. of its vapour =-Mp.= 6 7, when referred to hydrogen, and 4'63 when referred to air. Hence we may conclude that in oxide of triethylphosphine the elements are condensed in the same manner as in the majority of thoroughly investigated organic compounds. From the facility with which triethylphosphine is converted into the oxide by exposure to the air, even at ordinary temperatures, and * H^O-2 vols. vapour. 606 the very high boiling-point of the resulting compound, in consequence of which the vapour of the latter can exert but a very slight tension at the common temperature, I am induced to think that the phos- phorus-base may be used in many cases for the volumetric estimation of oxygen. When a paper ball soaked in triethylphosphine is passed up in a portion of air confined over mercury, the mercury immedi- ately begins to rise, and continues to do so for about two hours, after which the volume becomes constant, the diminution corresponding very nearly to the proportion of oxygen in the air. To obtain very exact results, however, it would be probably necessary in every case to remove the residual vapour of triethylphosphine by means of a ball saturated with sulphuric acid. Oxide of triethylphosphine exhibits in general but a small tendency to unite with other bodies. Nevertheless it forms crystalline com- pounds with iodide and bromide of zinc. I have examined more particularly the iodine-compound. Oxide of Triethylphosphine and Iodide of Zinc. — On mixing the solutions of the two bodies, the compound separates, either as a crystalline precipitate or in oily drops which soon solidify with crystalline structure. It is easily purified by recrystallization from alcohol, when it is deposited in often well-formed monoclinic crystals containing ^ R p() Znl = ^ jj^ pQ) Znl It is remarkable that this compound formed in presence of a large excess of hydriodic and even of hydrochloric acid. Oxide of Triethylphosphine and Dichloride of Platinum. — No pre- cipitate is formed on mixing the aqueous solutions of the two com- pounds, however concentrated. But on adding the anhydrous oxide to a concentrated solution of dichloride of platinum in absolute alcohol, a crystalline platinum-compound is deposited after a few moments. This compound is exceedingly soluble in water, easily soluble in alcohol, insoluble in ether. On adding ether to the alcoholic solution, the salt is precipitated, although with difficulty, in the crystalline state. The alcoholic solution, when evaporating spontaneously, yields beautiful hexagonal plates of the monoclinic system, frequently of very considerable dimensions. The crystals have the rather complex formula C« HB P, 03 Yi, C1. = 3[(C, H,), PO] + (C, H.), PCI,, 2Pt CI,. 607 On mixing the concentrated solution of the oxide with trichloride of gold, a deep yellow oil is separated, which crystallizes with diffi- culty after considerable standing. This compound is exceedingly soluble in water and in alcohol. When the aqueous solution is heated, the gold is reduced ; the transformation which the oxide of triethylphosphine undergoes in this reaction is not examined. Chloride of tin forms likewise an oily compound with the oxide : I have not succeeded in crystallizing this compound. Chloride of mercury is without any action on oxide of triethyl- phosphine. Oxy chloride of Triethylphosphine. — On passing a current of dry hydrochloric acid through a layer of oxide of triethylphosphine which is fused in a U-shaped tube surrounded by boiling water, brilliant crystals are soon deposited. These crystals disappear, how- ever, rapidly, the compound formed in the commencement of the reaction uniting with an excess of hydrochloric acid. The viscous liquid which ultimately remains behind, when heated loses the excess of hydrochloric acid, leaving an exceedingly deliquescent crystalline mass, very soluble in alcohol, insoluble in ether. For analysis, the new compound was washed with absolute ether and dried over sulphuric acid in vacuo, either at the common tem- perature or at 40°. Three chlorine-determinations in specimens of diiferent preparations, which, owing to the extraordinary avidity of this compound for moisture, exhibit greater discrepancies than are generally observed in experiments of this description, lead to the formula Cia H30 P2 O C12 = (C2 H.)3 PO, (C2 H5)3 PClr The dichloride of triethylphosphine cannot be formed by the action of hydrochloric acid upon the oxide. The oxychloride exhibits with other compounds the deportment of the oxide. It furnishes with dichloride of platinum the same platinum-salt which is obtained with the oxide. In a similar man- ner it gives with iodide of zinc the iodide of zinc-compound of the oxide previously described. Only once — under conditions not sharply enough observed at the time, and which I was afterwards unable to reproduce in repeated experiments — a compound of the oxy- chloride with iodide of zinc was formed. This substance, readily soluble in water and alcohol, crystallized from the latter solvent in beautiful colourless, transparent octahedra of the composition Cia H30 P2 O C12 Zn2 Ia= (C2 Hs)3 PO, (Ca H5)3 PC12, 2ZnI. VOL. X. 2 T 608 XIII. " Researches on the Phosphorus-Bases/' — No. IX. Phos- pharsonium Compounds. By A, W. HOFMANN, LL.D., F.R.S. Received July 24, 1860. The facility with which the bromide of bromethyl-triethylphos- phonium furnishes, when submitted to the action of ammonia and monamines, the extensive and well-defined group of phosphammo- nium- compounds, induced me to try whether similar diatomic bases containing phosphorus and arsenic might be formed by the mutual reaction between the bromethylated bromide and monarsines. There was no necessity for entering into a detailed examination of this class of compounds. I have, in fact, been satisfied to establish by a few characteristic numbers the existence of the phospharsonium-group. Action of Triethylarsine on Bromide of Bromethyl-triethyl- phosphonium. On digesting the two substances in sealed tubes at 1 00°, the usual phenomena are observed ; the reaction being complete after the lapse of twenty-four hours. The saline mass which is formed yields with oxide of silver in the cold, a powerfully alkaline solution, containing the hydrated oxide of ethylene-hexethylphospharsonium, It is thus obvious that the arsenic- base imitates triethylphosphine in its deportment with the brominated bromide. The two substances simply combine to form the dibromide of the phospharsonium, [(C. H4 Br) (C, H5)s P] Br + (C, H5)3 As= [(C, HJ» <£ JJ •>• JJ V The alkaline solution of the oxide of the phospharsonium exhibits the leading characters of this class of bases ; I may therefore refer to the account which I have given of the oxide of diphosphonium. The saline compounds likewise resemble those of the diphosphonium. The dichloride and the di-iodide were obtained in beautiful crystalline needles, exhibiting a marked tendency to form splendidly crystallized double compounds. I have prepared the compounds of the dichlo- ride with chloride of tin, bromide of zinc, trichloride of gold, and 609 lastly with dichloride of platinum. The latter compound was ana- lysed in order to fix the composition of the series. Platinum-salt. — The product of the reaction of triethylarsine upon the bromethylated bromide was treated with oxide of silver in the cold, and the alkaline solution thus obtained, saturated with hydrochloric acid and precipitated with dichloride of platinum. An exceedingly pale-yellow, apparently amorphous precipitate of diphos- phonic appearance was thrown down, almost insoluble in water, but dissolving in boiling concentrated hydrochloric acid. The hydro- chloric solution deposited, on cooling, beautiful orange-red crystals, resembling those of the diphosphonium-platinum-salt. The crystals, according to the measurement of Quintino Sella, belong to the tri- metric system. The analysis of the platinum-salt led to the formula CMH31PAsPt2Cl6=r(C2H4)" %%>•* l"ci2)2PtC!2. L (C2 H5)3 As J The phospharsonium-compounds, and more especially the hydrated oxide of the series, are far less stable than the corresponding terms of the diphosphonium- and even of the phosphammonium-series. If the product of the action of triethylarsine upon the brominated bro- mide be boiled with oxide of silver instead of being treated in the cold, not a trace of the phospharsonium- compound is obtained. The caustic solution which is formed, when saturated with hydro- chloric acid and precipitated with dichloride of platinum, furnishes only the rather soluble octahedral crystals of the oxethylated triethyl- phosphonium-platinum-salt *. The nature of this transformation is clearly exhibited when a solution of the dioxide of phospharsonium is submitted to ebullition. Immediately the clear solution is rendered turbid from separated triethylarsine, which becomes perceptible, moreover, by its powerful odour, the liquid then containing the oxide of the oxethylated triethylphosphonium, [(C2H4)"(C2H5)6PAs]"1 [(C2H50)(C2H6)3P]10 J^-^AJsAs- * See the following Abstract. H2 -s- H 2T2 610 XIV. " Researches on the Phosphorus-Bases." No. X. — Meta- morphoses of Bromide of Bromethylated Triethylphospho- nium. By A. W. HOFMANN, LL.D., F.R.S. Received July 24, 1860. Among the several products of transformation into which the bro- mide of bromethyl-triethylphosphonium is converted when submitted to the action of reagents, the substances formed by its union with bodies similar to ammonia, have hitherto almost exclusively occupied my attention. I have, however, of late examined a variety of other changes of this body, which deserve to be noticed. When heated, the bromide begins to evolve hydrobromic acid at a temperature of about 200°, which continues for a considerable length of time. The product of this reaction is evidently the bromide of vinyl-triethylphosphonium, [(C, H4 Br)(C2 H3)3 P] Br=H Br+ [(C, H3) (C, Hs)3 P] Br. It is, however, difficult to obtain the substance pure by this process, since the temperature at which the last portion of hydrobromic acid is eliminated closely approximates the degree of heat at which the vinyl-body is entirely destroyed ; and since the latter compound may be obtained with the greatest facility by other processes*, I have not followed up any further this direction of the inquiry. I have already mentioned, in a previous note, the deportment of * The hydrated di-oxide of ethylene-hexethyl-diphosphonium, when submitted to distillation, undergoes decomposition ; two different phases are to be distin- guished in this metamorphosis. At about 200° the base begins to disengage the vapour of triethylphosphine, the residuary solution retaining hydrated oxide of vinyl-triethylphosphonium , [(C, H4)"(C2 H5)6 P]"o2 = (C2 Ha)3 P+H2 0+£(C* H>) V* H*>3 P O, the latter yielding at a higher temperature the oxide of triethylphosphine together with ethylene, C(C2 H3) (C2 H5)3 P] 1 0 = c2 H4+(C2 H5)3PO. The vinyl-compound is even more readily obtained by the action of silver-salts, such as acetate of silver, at the temperature of 100°, on the bromethylated bromide. 611 the bromethylated bromide with oxide of silver ; the whole of the bromine is eliminated in the form of bromide of silver, a new base being formed. According to circumstances, this base may be the vinyl-compound previously mentioned, or another body differing from the latter by containing the elements of one molecule of water in addition. This substance, which is always formed when the reaction takes place in moderately dilute solutions, is the oxide of a phosphonium, with three molecules of ethyl substituted for three equivalents of hydrogen, the fourth equivalent of hydrogen being replaced by an oxygenated radical C2 H5 O, arising from the radical C2 H4 Br by the insertion of HO in the place of Br [(C2 H4 Br) (C2 H6)3 P] Br + 2^ j 0 = 2AgBr + KC* H*HO) ^l1^ g 1 O. I have fixed the nature of this compound by the analysis of the iodide, of the platinum-salt and of the gold-salt, and, moreover, by the study of several remarkable transformations which it undergoes when submitted to the action of reagents. It appeared of some interest to ascertain whether the oxethylated might be reconverted into the bromethylated base. The chloride of the former is energetically attacked by pentabromide of phosphorus; oxybromide of phosphorus and hydrobromic acid are abundantly evolved, and the residue of the reaction contains the chloride of bromethylated trie thy Iphosphonium. [(C2 H5 O) (Ca H5)3 P]Cl + PBr5=HBr + POBr3+ [(C2 H4 Br) (C2 H5 )8 P]O. Thus it is seen that the molecular group C2 H. O, which we assume as hydrogen-replacing in this salt, suffers under the influence of pentabromide of phosphorus, alterations identical with those which it is known to undergo under similar circumstances, when conceived as a constituent of alcohol. If we consider the facility with which the bromethylated triethyl- phosphonium is converted into the oxethylated compound, by the action of oxide of silver, and the simple re-formation of the first- mentioned body by means of pentabromide of phosphorus, a great variety of new experiments suggest themselves. As yet but little progress has been made in this direction ; one of the reactions, how- ever, which I have studied deserves even now to be mentioned. The salts of bromethylated and oxethylated triethylphosphonium 612 may be regarded as tetrethyl-phosphonium-salts, in which an equiva- lent of hydrogen in one of the ethyl-molecules is replaced by bromine and by the molecular group HO respectively. Bromide of tetrethylphosphonium [(Ca H4 H ) (Ca H5)3 P] Br, Bromide of bromethylated tri- 1 rfr TT -n \ /p -p- x p-i -n, ethylphosphonium . ....... j (C2 H4 Br ) (C2 H6)3 P Br, [(C2H4HO)(C2H5)3P] Br; and the question arose, whether the bromethylated compound might not be converted, simply by reduction, into a salt of tetrethyl- phosphonium. This transformation may, indeed, be effected with- out difficulty. On acidulating the solution of the bromethylated bromide with sulphuric acid and digesting the mixture with granu- lated zinc, the latent bromine is eliminated as hydrobromic acid, its place being at the same time filled by 1 equiv. of hydrogen, [(C2 H4 Br) (C2 H5)3 P]Br+2H = HBr+ [(C2 H5)4 P]Br. It was chiefly the facility with which a tetrethyl-phosphonium- compound may be obtained from the brominated bromide, that in- duced me to designate the hydrogen-replacing molecules C2 H4 Br, and C2 H5 O, which we meet with in the compounds above described, as bromethyl and oxethyl. It remained to be ascertained whether these compounds might actually be formed by means of direct sub- stitution-products of ethyl-compounds. It was with the view of deciding this question that I have examined the deportment of tri- ethylphosphine with the monochloriuated chloride and the mono* brominated bromide of ethyl. The former of these substances has been long known, having been investigated by Regnault many years ago ; the latter had not been hitherto obtained. I have prepared it by submitting bromide of ethyl to the action of dry bromine under pressure*. It is a heavy aromatic liquid boiling at 110°. The chlorinated chloride and the bromiuated bromide of ethyl, although essentially different in their physical properties from dichloride and dibromide of ethylene, with which they are isomeric, nevertheless resemble the ethylene-compounds in their deportment with triethylphosphine. In both cases the final product of the reaction is a salt of hexethyl- * In addition to the monobrominated bromide of ethyl, (C4 H t Br) Br, there is also formed in this reaction the dibrominated bromide, (C4 H3 Br2) Br. 613 ated ethylene-diphosphonium. I have identified these salts with those obtained by means of dichloride and dibromide of ethylene, both by a careful examination of their physical properties, and by the analysis of the characteristic iodide and of the platinum-salt. I have not been able to trace in the first of these reactions a salt of chlorethylated triethylphosphonium ; but I have established by experiment that in the reaction between triethylphosphine and brominated bromide of ethyl, the formation of bromethyl-triethylphosphonium invariably precedes the production of the diphosphonium-compound. XV. " Researches on the Phosphorus-Bases." — No. XI. Experi- ments in the Methyl- and in the Methylene- Series. By A. W. HOFMANN, LL.D., F.R.S. Received July 24, 1860. In former notes I have repeatedly called attention to the trans- formation of the bromide of bromethylated triethylphosphonium under the influence of bases. In continuing the study of these reac- tions, I was led to the discovery of a very large number of new com- pounds, the more important ones of which are briefly mentioned in this abstract. HYBRIDS OF ETHYLENE-DIPHOSPHONIUM. Action of Trimethylphosphine upon Bromide of Bromethyl-triethyl- phosphonium . These two bodies act upon each other with the greatest energy, and moreover exactly in the manner indicated by theory. The resulting compound was of course examined only so far as was neces- sary to establish the character of the reaction. The dibromide of the hybrid diphosphonium is more soluble than the hexethylated compound formerly described, which in other respects it resembles. Oxide of silver eliminates the extremely caustic base which yields with hydrochloric acid and dichloride of platinum a pale-yellow platinum-salt, Cn H28 P2 Pt2 C16= [(C2 H4)» ^^pjci, 2Pt C12, separating in scales from boiling water. 614 The salts of the hybrid diphosphonium crystallize like those of the hexethylated diphosphonium, but, so far as they have been examined, are somewhat more soluble. This remark applies especially to the iodide. It seemed worth while to try whether the bromide of brom- ethylated triethylphosphonium was capable of fixing a molecule of phosphoretted hydrogen. It was found, however, that the two bodies do not act upon one another. Phosphoretted hydrogen gas, passed through the alcoholic solution of the bromide, either cold or boiling, did not seem to affect it in any way. Action of Trimethylphosphine on Dibromide of Ethylene. This reaction exhibits a repetition of all the phenomena observed in that which takes place between the dibromide and triethylphos- phine. The process is completed sooner, if possible, than in the ethyl-series. The lower boiling-point and the overpowering odour of trimethylphosphine render it advisable to mix the materials with considerable quantities of alcohol or ether ; and on account of the extreme oxidability of the phosphorus-compound, it is best to ope- rate in vessels filled with carbonic acid and subsequently sealed before the blowpipe. After digestion for a short time at 100°, the mixture of the two liquids solidifies to a hard, dazzling, white, crystalline mass containing the two bromides, C5 H13 P Br2 = [(C2 H4 Br) (C H8)8 P] Br, OH P Br — CHFBr_ one or the other predominating according to the proportions in which the two bodies were allowed to act upon one another. It was not difficult to establish the nature of these two compounds by numbers. The solution of the saline mass in absolute alcohol, deposits, on cooling, beautiful prismatic crystals, consisting of the bromide of bromethyl-trimethylphosphonium almost chemically pure, while the diphosphonium-bromide remains in solution. The nature of the monophosphonium-compound was fixed by a bromine determination in the bromide, and by the analysis of a platinum-salt beautifully crystallized in needles containing 615 C6 H13 Br P PtCl3= [(Ca H4 Br)(C H,)3 P] Cl, PtCl,. Treatment of this platinum-salt with sulphuretted hydrogen yielded an extremely soluble and deliquescent chloride, which was not ana- lysed, but submitted to the action of oxide of silver, when it furnished the oxide of the corresponding oxethylated compound H The caustic liquid was converted by hydrochloric acid into the easily soluble chloride corresponding to the oxide ; and this chloride, when treated with dichloride of platinum, deposited the platinum- salt of the oxethylated trimethylphosphonium in well-formed octa- hedra extremely soluble in water, containing C. Hu P O PtCl,= [(C2 H5 0)(C H3)3 P]C1, PtCl2. Salts of Hexmethylated Ethylene-diphosphonium. Dibromide. — The preparation of this salt has already been men- tioned. It is extremely soluble in water, and even in absolute alcohol, insoluble in ether. In vacua over sulphuric acid it solidifies into a mass of acicular crystals, which are exceedingly deliquescent. The dibromide, treated with oxide of silver, yields the correspond- ing dioxide, which forms with acids a series of salts resembling the corresponding ethyl-compounds. Of these I have prepared only the Di-iodide, which crystallizes in difficultly soluble needles of the composition C H P I— ~ (CH3)3P surpassing in beauty the corresponding ethyl-compound, and the — Platinum-salt. — This is an apparently amorphous precipitate, which is nearly insoluble in water, dissolves with extreme slowness in boiling hydrochloric acid, and separates therefrom on cooling in golden-yellow laminae, very much like those of the platinum-salt of the hybrid ethylene-trimethyl-triethyl-diphosphonium. It con- sists of — C. H22 P2 Pt, C10= [(C. H4)» £ Jj»° p]"ci3) 2PtCV GIG METHYLENE GROUP. Action of Triethylphosphine on Di-iodide of Methylene. Triethylphosphine and di-iodide of methylene act so powerfully on one another, that it is necessary to moderate the reaction by the pre- sence of a considerable quantity of ether. The reaction is very soon completed, even when the mixture is largely diluted, especially if it be heated to 100° in sealed tubes. The saline residue left after the evaporation of the ether is immediately seen to be a mixture of several compounds, one of which — a sparingly soluble iodide crystallizing in long needles — at once arrests attention. From analogy we might expect to find in the saline mixture the compounds [(CH2I)(C2HS)3P]I, [(CH2)»(C2HS)6P2]"I2. Experiment has, however, established the presence of the first only. The difficultly soluble crystals just mentioned are easily purified, being readily soluble in water, sparingly in alcohol, insoluble in ether. Their solution in boiling alcohol yields splendid needles fre- quently an inch long, and possessing extraordinary lustre. Analysis prove this beautiful salt to be the first of the above-mentioned com- pounds. The new iodide behaves with nitrate of silver like the bromide of bromethylated triethylphosphonium ; half the iodine is eliminated in the form of iodide of silver. It differs, however, from the bromide in its deportment with oxide of silver which, after removal of the accessible iodine, leaves the latent iodine untouched, even after protracted ebullition. A powerfully alkaline solution is thus obtained containing the base c7H18iPO=KCH^)^H'\r The crystals of the iodide were transformed into the chloride by means of chloride of silver, and the solution was precipitated by dichloride of platinum. The precipitate is very sparingly soluble in cold water, but may be recrystallized from a considerable quantity of boiling water. As the liquid cools, splendid needle-shaped crystals are deposited containing C7 H]7 1 P PtCl3= [(C H2 1)(Ca H5)3 P]C1, PtCl2. 617 The sparingly soluble iodide is present in proportionally small quan- tity only among the products of the action of di-iodide of methylene on triethylphosphine. I have in vain endeavoured to detect among these products anything of the nature of a diphosphonium-com- pound. On treating the mother-liquor of the sparingly soluble iodide with chloride of silver, and the dilute filtered solution with dichloride of platinum, a few needles of the iodated platinum-salt are still deposited; but after considerable evaporation the solution yields crystals, all of which exhibit an octahedral habitus. I was equally unsuccessful in a particular experiment, in which I subjected di-iodide of methylene to the action of a large excess of triethyl- phosphine ; and a similar report must be made of the attempt to produce the desired body by treating the ready prepared iodide with triethylphosphine, according to the equation [(C H2 IXC.H.), P]I + (C, H5)3 P=[(C H2)» (C, H5), PJ» I2. The examination of the mother-liquor of the sparingly soluble iodide is a difficult and thankless proceeding ; nevertheless, by a suffi- cient number of iodine- and platinum-determinations, it may be shown to be a mixture of four different compounds. The mother-liquor is thus found to contain, together with the hydriodate of the phos- phorus-base, two crystallizable iodides differing in solubility, and to be separated from one another only by a great number of crystallizations. The more soluble salt is the iodide of oxymethylated triethyl- phosphonium, corresponding to the iodomethylated compound ; the less soluble salt is the iodide of methyl- trie thylphosphonium. The last mother-liquors contain considerable quantities of oxide of triethylphosphine. Iodide of Oxymethyl-triethylphosphonium. This salt is extremely soluble both in water and in alcohol, even in absolute alcohol, and crystallizes only after the alcohol has been completely evaporated. The crystals, resembling the frosty efflores- cences on a window-pane, contain C7 H18 O P 1 = [(C H3 O) (C2 H5)3 P] I. The iodide, treated with oxide of silver, is converted into the corre- sponding caustic oxide, which, when mixed with hydrochloric acid and dichloride of platinum, yields a rather easily soluble platinum- salt of an octahedral habitus. 618 Iodide of Methyl-triethylphosphonium. The nature of the less soluble iodide was determined by an iodine- determination, and by the analysis of the platinum-salt. The iodide dissolves in water and in alcohol, but is insoluble in ether. By adding ether to the alcoholic solution, tolerable crystals are obtained. This compound is most conveniently purified by precipitating the alcoholic mother-liquor, after freeing it by crystallization as far as possible from the iodomethylated iodide, with a quantity of ether insufficient to precipitate the whole, so that the greater part of the iodides may remain in solution. The iodide thus prepared contains C,H,8PI=[(CH3)(C2H5)3P]I. For further verification of this formula the crystals were deiodized with silver-oxide, and the caustic liquid thus obtained was saturated with hydrochloric acid and precipitated by dichloride of platinum. The platinum -salt, which crystallizes in beautiful octahedra, was found to contain C, H18 1> PtCl3= [(C Ha) (C, H.), P]C1, Ptd, The two iodides are accompanied by a considerable quantity of oxide of triethylphosphine, which immediately separates in oily drops on treating the last mother-liquor with potash. Its presence was like- wise unmistakeably recognized by the preparation of the platinum - salt. If the last mother- liquor of the iodine-compounds be deiodized and mixed with hydrochloric acid and dichloride of platinum, a quan- tity of octahedral salts separates in the first place, which are removed by sufficient concentration ; the remaining liquid, when mixed with alcohol and ether, yields a crystalline precipitate, which separates from alcohol by spontaneous evaporation in the beautiful large hexagonal tables consisting of the platinum-salt of the oxychloride of triethylphosphine, which has been more fully described in one of the previous notes on these researches. The formation of the four compounds contained in the mother- liquor of the sparingly soluble iodide is illustrated by the following equations : — 3)3P] + CHJ2+H20=[(C2H5)3HP]H-[(CH30)(C2H5)3P]I 2 + H30=[(C2HS)3HP]I+[(CH3)(C2H6)3P]I + (C2H5 619 XVI. " Researches on the Phosphorus-Bases."— No. XII. Rela- tions between the Monoatomic and the Polyatomic Bases. By A. W. HOFMANN, LL.D., F.R.S. Received August 17, 1860. In recording my experiments on the derivatives of triethylphos- phine, I have had more than one opportunity of alluding to the energy and precision which characterize the reactions of this com- pound. The usefulness of triethylphosphine as an agent of research has more particularly manifested itself in the study of the poly- atomic bases, the examination of which, in continuation of former inquiries, was naturally suggested by the beautiful researches on the polyatomic alcohols published during the last few years. In the commencement these studies were almost exclusively performed with reference to derivatives of ammonia ; but the results obtained in the examination of triethylphosphine have, in a great measure, changed the track originally pursued, and of late I have generally preferred to solve the problems which I had proposed to myself, by the aid of the phosphorus-bases. The light which the study of these compounds throws upon the nature of the polyatomic bases generally, will be fully appreciated by a retrospective glance at the deportment of triethylphosphine under the influence of dibromide of ethylene, and a comparison of the products formed in this reaction with the results suggested by theory. A simple consideration shows that the action of diatomic bro- mides upon bases must give rise to the formation of several classes of compounds. Let us examine by way of illustration the products which may be expected to be formed in the reaction between am- monia and dibromide of ethylene. The diatomic bromide being capable of fixing two molecules of ammonia, we have in, the first place four diatomic bromides of the formulae [(C2H4)» H.NJ»Br. [(CaH1)a"H1N,]»Br1 [(C3H1),"HJNJ"Bra [(C.H.)." N,]"Br,. VOL. X. 2 V 620 These are, however, by no means the only salts which, in accord- ance with our present conception of diatomic compounds, may be formed in this reaction. Taking into consideration the general deportment of dibromide of ethylene, there could be no doubt that, under certain conditions, this body would act with ammonia as a monoatomic compound, giving rise to another series of bodies, in which the hydrogen would be more or less replaced by the mono- atomic molecule C2 H4 Br, viz. [(C4H4Br)H3N]Br [(C2H4Br)2H2N]Br [(C2H4Br)3HN]Br [(C2H4Br)4 N]Br. Further, if the reaction took place in the presence of water, it was to be expected that the latent bromine of these salts, wholly or par- tially eliminated in the form of hydrobromic acid, would be replaced by the molecular residue of water, and thus, independently of any mixed compounds containing simultaneously bromine and oxygen, a series of salts might be looked for, in which a molecule C2 H4 (H0)= C2 H5 O would enter monoatomically. [(C2H50) H3N]Br [(C2H50)2H2N]Br [(C2H30)3H N]Br [(C2H50)4 N]Br. Lastly, remembering the tendency exhibited by ethylene-com- pounds to resolve themselves in the presence of alkalies into vinyl- products, it appeared not improbable that a fourth series of bodies would likewise be formed, [(C,H.) H3N]Br [(C2H3)2HaNJBr [(C2H3)3HN]Br [(C2H3)4 N]Br. In the experiments on the action of dibromide of ethylene upon ammonia, which I have already partly published, and which, in a more connected form, I hope soon to lay before the Royal Society, I have not, indeed, met with the whole of these compounds ; but in the place of the deficient members of the groups new products have made their appearance, whose formation in the present state of our 621 knowledge could scarcely have been predicted, and thus the problem of disentangling the difficulties of this reaction becomes a task of very considerable difficulty. Nor did the action of dibromide of ethylene upon ethylamine, diethylamine, and triethylamine, which I subsequently studied, afford a sufficiently simple expression of the transformations suggested by theory. The difficulties disappeared at once when the experiment was repeated in the phosphorus-series. In the reaction with dibromide of ethylene, the sharply-defined characters of triethylphosphine exhibited themselves with welcome distinctness, and in consequence more especially of the absence of unreplaced hydrogen — whereby the formation of a large number of compounds of subordinate theoretical interest was excluded — the general cha- racter of the reaction, the recognition of which was the object of the inquiry, became at once perceptible. I have shown that the action of dibromide of ethylene upon triethylphosphine gives rise to the formation of four different com- pounds, viz. [(C2H4)" (C2H5)6P2]"Br2 [(C2H4Br)(C2H6)3P] Br [(C2H50)(C2H5)3P] Br [(C2H3) (C2H5)3P] Br, each of which represents one of the four groups of compounds, which under favourable circumstances may arise from the mutual reaction between ammonia and dibromide of ethylene, the produc- tion of a greater number of terms being impossible on account of the ternary substitution of triethylphosphine. Whilst going on with the researches on the phosphorus-bases which I have taken the liberty of submitting to the Royal Society, in notes sketched as I advanced, I have not altogether lost sight of the experiments in the nitrogen-series, which had originally sug- gested these inquiries. Numerous nitrogenated bases, both mono- atomic and diatomic, with which I have become acquainted during this investigation, must be reserved for a future communication. I may here only remark, that these substances, although differing in several points, nevertheless imitate in their general deportment so closely the corresponding terms of the phosphorus-series, that the 2 u2 622 picture which I have endeavoured to delineate of the phosphorus- compounds, illustrates in a great measure the history of the nitrogen- bodies. In conclusion, a few words about the further development of which the experiments on the polyatomic bases appear to be capable, and about the direction in which I propose to pursue the track which they have opened. Conceived in its simplest form, the transition from the series of monoatomic to that of diatomic bases, may be referred to the intro- duction of a monochlorinated or a monobrominated alcohol-radical into the type ammonia, the chlorine and bromine thus inserted furnishing the point of attack for a second molecule of ammonia. If in bromide of ethylammonium — to pass from the phosphorus- series to the more generally interesting nitrogen-series — >we replace 1 equiv. of the hydrogen in ethyl by bromine, we arrive at bro- mide of bromethylammonium, which fixing a second equivalent of ammonia, is converted into the dibromide of ethylene-diammonium, the latent bromine becoming accessible to silver-salts. [(C3 H4 Br) H3 N] Br + H3 N = [(Ca H4)" H6 NJ" Br2. The further elaboration of this reaction indicates two different methods for the construction of the polyatomic bases of a higher order. In the first place, the number of ammonia-molecules, to be incorporated in the new system, may be increased by the gradually advancing bromination of the radical. By the further bromination of ethyl in bromide of bromethylammonium and the action of ammonia on the bodies thus produced, the following salts may be generated : — [(C, H3 Br2) H3 N] Br + 2H3 N = [(C2 H8)'" H9 N,]"' Br3 [(C2H2Br8)H3N]BrH-3H3N=[(C2H2)'^ H12N4]"" Br4 [(C2H Br4)H3N]Br + 4H3N = [(C2H)'"'' H15N6]'"" Br5 [(C2 Br5)H3N] Br+5H3N = [(C2 )»"" HJ8 NJ""" Bre. Again, the fixation of the ammonia-molecules may be attempted, not by the progressive bromination of the ethyl, but by the accumu- lation of monobrominated ethyl-molecules in the ammonium -nucleus. The bromide of di-bromethylammonium, when submitted to the action of ammonia, would thus yield the tribromide of a triammo- 623 nium ; the bromide of tri-bromethylamrnonium, the tetrabromide of a tetrammonium ; and lastly, the bromide of tetrabromethylammo- nium, the pentabromide of a pentammonium. [(C2H4Br)2H2N]Br+2H3N = [(C2H4)2"H8 NJ" Br3 [(C2H4Br)3H N]Br+3H8N = [(C,HJ8"H10NJ'" Br4 [(C, H4 Br)4 N] Br +4H3N = [(Cf H4)4" H12 N J'"" Br5. As yet the bromination of the alcohol-bases presents some diffi- culty ; appropriately selected reactions, however, will doubtless fur- nish the several brominated bases. They may probably be obtained by indirect processes, similar to those by which years ago I succeeded in preparing the chlorinated and brominated derivatives of phenyl- amine ; or these bodies may be generated by the action of penta- chloride or pentabromide of phosphorus upon the oxethylated bases, a process, which, to judge from the few experiments recorded in one of the preceding sketches, promises a rich harvest of results. I have but a faint hope that I may be able to trace these new paths in the numerous directions which open in a variety at once tempting and perplexing. Inexorable experiment follows but slowly the flight of light-winged theory. The commencement is never- theless made, and even now the triammonium- and tetrammonium- compounds begin to unfold themselves in unexpected variety. One of the most remarkable compounds belonging to the triammonium- group is diethylene triamine, This base, the first triacid triammonia, forms splendid salts of the formula [(C2H4)''2H8N3]'»C13) which will be the subject of a special communication. 624 November 15, 1860. Major-General SABINE, R.A., Treasurer and Vice-President, in the Chair. In accordance with the Statutes, notice was given from the Chair of the ensuing Anniversary Meeting for the election of Council and Officers. David Forbes, Esq., was admitted into the Society. The following communication was read : — I. " Oil the Laws of the Phenomena of the larger Disturbances of the Magnetic Declination in the Kew Observatory : with notices of the progress of our knowledge regarding the Magnetic Storms/' By Major-General EDWARD SABINE, R.A., Treas. and V.P. Received November 15, 1860. The laws manifested by the mean effects of the larger magnetic disturbances (regarded commonly as effects of magnetic storms) have been investigated at several stations on the globe, being chiefly those of the British Colonial Observatories ; but hitherto there has been no similar examination of the phenomena in the British Islands themselves. The object of the present paper is to supply this de- ficiency, as far as one element, namely the declination, is concerned, by a first approximation derived from the photographs in the years 1858 and 1859, of the self-recording declinometer of the observatory of the British Association at Kew ; leaving it to the photographs of subsequent years to confirm, rectify, or render more precise the results now obtained by a first approximation. The method of in- vestigation is simple, and may be briefly described as follows : — The photographs furnish a continuous record of the variations which take place in the direction of the declination-magnet, and ad- mit of exact measurement in the two relations of time, and of the amount of departure from a zero line. From this automatic record, the direction of the magnet is measured at twenty-four equal inter- vals of time in every solar day, which thus become the equivalents of the "hourly observations" of the magnetometers in use at the Colonial Observatories. These measures, or hourly directions of the magnet, are entered in monthly tables, having the days of the month 625 in successive horizontal lines, and the hours of the day in vertical columns. The " means " of the entries in each vertical column indi- cate the mean direction of the magnet at the different hours of the month to which the table belongs, and have received the name of " First Normals." On inspecting any such monthly table, it is at once seen that a considerable portion of the entries in the several columns differ considerably from their respective means or first nor- mals, and must be regarded as " disturbed observations." The laws of their relative frequency, and amount of disturbance, in different years, months and hours, are then sought out, by separating for that purpose a sufficient body of the most disturbed observations, com- puting the amount of departure in each case from the normal of the same month and hour, and arranging the amounts in annual, monthly, and hourly tables. In making these computations, the first normals require to be themselves corrected, by the omission in each vertical column of the entries noted as disturbed, and by taking fresh means, representing the normals of each month and hour after this omission, and therefore uninfluenced by the larger disturbances. These new means have received the name of " Final Normals," and may be de- fined as being the mean directions of the magnet in every month and every hour, after the omission from the record of every entry which differed from the mean a certain amount either in excess or in defect. In this process there is nothing indefinite ; and nothing arbitrary save the assignment of the particular amount of difference from the normal which shall be held to constitute the measure of a large dis- turbance, and which, for distinction sake, we may call " the separating value" It must be an amount which will separate a sufficient body of disturbed observations to permit their laws to be satisfactorily ascertained ; but in other respects its precise value is of minor sig- nificancy ; and the limits within which a selection may be made, without materially affecting the results, are usually by no means narrow ; for it has been found experimentally on several occasions, that the Ratios by which the periodical variations of disturbance in different years, months and hours are characterized and expressed, do not undergo any material change by even considerable differences in the amount of the separating value. The separating value must ne- cessarily be larger at some stations than at others, because the abso- lute magnitude of the disturbance- variation itself is very different in 626 different parts of the globe, as well as its comparative magnitude in relation to the more regular solar-diurnal variation ; hut it must be a constant quantity throughout at one and the same station, or it will not truly show the relative proportion of disturbance in different years and different months. The strength of the Kew establishment being insufficient for the complete work of a magnetic observatory, the tabulation of the hourly directions from the photographic records has been per- formed by the non-commissioned officers of the Royal Artillery, employed under my direction at Woolwich, where this work has been superintended by Mr. John Magrath, the principal clerk, as have been also the several reductions and calculations, which have been made on the same plan as those of the Colonial Observatories. In the scale on which the changes of direction of the declination- magnet are recorded in the Kew photographs, one inch of space is equivalent to 22' '04 of arc. On a general view and consideration of the photographs during 1858 and 1859, 0'15 inch, or 3''31 of arc appeared to be a suitable amount for the separating value to be adopted at that station ; consequently every tabulated value which differed 3'*31 or more, either in excess or defect from the -final nor- mal of the same month and hour, has been regarded as one of the larger disturbances, and separated accordingly. The number of dis- turbed observations in the two years was 2424 (viz. 1211 in 1858, and 1213 in 1859), being between one-seventh and one-eighth of the whole body of hourly directions tabulated from the photographs, of which the number was 17,319. The aggregate valne of disturbance in the 24 24 observations, was 14,901 minutes of arc ; of which 7207 minutes were deflections of the north end of the magnet to the west, and 7694 to the east ; the easterly deflections thus having a slight preponderance. The number of the disturbed observations, as well as their aggregate values, approximated very closely in each of the two years, 1859 being very slightly in excess. The decennial period of the magnetic storms, indicated by the observations at the British Colonial Observatories between 1840 and 1850, had led to the antici- pation that the next epoch of maximum of the cycle might take place in the years 1858-1859. The nearly equal proportions in which the numbers and aggregate values of the larger disturbances took place in 1858 and 1859 are so far in accordance with this view. Should 627 the records of the succeeding years at Kew, made with the same in- struments, and Examined by the same method, show decreasing dis- turbance in 1860 and 1861, the precise epoch of the maximum indi- cated by the records of the Kew declinometer will be " the end of 1858 or commencement of 1859." In Table I. are shown the aggregate values of disturbance in the two years, arranged under the several hours of solar time in which they occurred. They are also divided into the two categories of westerly and easterly deflections, since the experience gained at other stations has now fully established that the westerly and easterly dis- turbance-deflections are characterized in all parts of the globe by distinct and dissimilar laws. The Ratios are also shown which the aggregate values at the different hours, both of the westerly and the easterly deflections, bear to their respective mean values, — or, in other words, to the sums respectively of the westerly and easterly deflec- tions at all the hours, divided by 24, and taken as the respective units. TABLE I. — Showing the aggregate values of the larger disturbances of the Declination at the different hours of solar time in 1858 and 1859, derived from the Kew Photographs ; with the Ratios of disturbance at the several hours to the mean hourly value taken as the Unit. Mean Westerly deflections. Easterly deflections. Mean astronomi- civil cal hours. Aggregate values- (Minutes of arc.) Ratios. Aggregate values. (Minutes of arc.) Ratios. hours. 18 553-9 1-85 118-9 0-37 6A.M. 19 549-3 1-83 120-9 0-38 7A.M. 20 4429 1-48 115-2 0-36 8 A.M. 21 370-1 1-23 121-2 0-38 9A.M. 22 376-9 1-26 104-6 0-33 10 A.M. 23 361-8 121 125-8 0-39 11 A.M. 0 413-7 1-38 173-0 0-54 Noon. I 431-1 1-44 153-3 0-48 1 P.M. 2 459-8 1-53 173-0 0-54 2 P.M. 3 513-0 1-71 108-4 0-34 3 P.M. 4 403-9 1-35 141-0 0-44 4 P.M. 5 343-8 1-15 164-8 0-51 5 P.M. 6 282-5 0-94 291-1 0-91 6 P.M. 7 110-7 0-37 381-8 1-19 7 P.M. 8 65-6 0-22 499-0 1-56 8 P.M. 9 88-2 0-29 572-9 1-79 9 P.M. 10 59-0 0-20 724-3 2-25 10 P.M. 11 357 0-12 767-8 2-38 11 P.M. 12 146-7 0-49 709-5 2-21 Midnight. 13 141-8 0-47 634-8 ]-98 1 A.M. 14 146-7 0-49 577-2 1-80 2A.M. 15 151-5 0-51 464-8 1-45 3A.M. 16 289-5 0-97 305-8 0-95 4 A.M. 17 458-9 1-53 144-9 0-45 5 A.M. Mean hourly value 299'9=-l'00 Mean hourly value 320-6 = 1-00 628 The westerly and easterly deflections in the British Islands, as represented by the automatic records at Kew, are obviously governed, as in all other parts of the globe where the phenomena have been analysed, by distinct laws. The westerly deflections have their chief prevalence from 5 A.M. to 5 P.M., or during the hours of the day ; the easterly deflections, on the other hand, prevail chiefly during the hours of the night, the ratios being above unity from 7 P.M. to 3 A.M., and below unity at all other hours. The easterly have one decided maximum, viz. at 11 P.M., towards which they steadily and con- tinuously progress from 5 P.M., and from which they as steadily and continuously recede until 5 A.M. the following morning. The westerly deflections appear to have two epochs of maximum, one from 6 to 7 A.M., the other about 3 P.M., progressing regularly towards the first named from 3 A.M., and receding from it to 9 A.M. ; at 9, 10, and 1 1 A.M. the ratios remain almost sensibly the same, but towards noon they begin to increase afresh, and continue to do so progressively to the second maximum at 3 P.M., from which hour they progressively decrease to 7 P.M. Those ratios which are less than unity, viz. those of the westerly deflections from 6 P.M. to 4 A.M., and of the easterly from 4 A.M. to 6 P.M., do not in either case exhibit the same decided tendency to one or two well-marked minima, as the ratios which are above unity do in both cases towards their maxima. It is possible, however, that this may in some degree be explained by the following consideration : — The aggregate values of the disturbances prevailing at the different hours, as stated in the Table, are those which have prevailed, not only over the forces which would retain the magnet in its mean po- sition, but also over any disturbing influences in an opposite direc- tion, which may be conceived to have existed contemporaneously ; and we cannot but suppose that as both westerly and easterly dis- turbances do record themselves as prevailing at the same hours on different days, that these opposite influences may sometimes coexisty neutralizing each other and not appearing in the record. We may reasonably suppose that the degree in which the aggregate values in the Table, both westerly and easterly, may be diminished thereby at the different hours, may be in some measure indicated by the dis- parity, or the reverse, in the amount of the aggregate values of dis- turbance in the opposite directions at those hours. Thus we may 629 suppose that at a particular hour, 11 P.M. for example, when the amount of westerly deflections is very small, and of easterly very great, the diminution of the aggregate values of either by mutual counterbalance may be extremely small, while of equal absolute amount in both. Now a very small amount deducted from the large aggregate easterly value will scarcely have any effect whatsoever on the ratio at that hour to its unit or mean hourly value ; whereas the same small amount deducted from the far less aggregate westerly value at the same hour would have a far more sensible effect upon its ratio. Assuming, therefore, the probability that westerly and easterly disturbing influences do sometimes coexist and neutralize each other in the record, and that we may in some degree judge of the respective amounts of the conflicting influences at the several hours by the means above stated, we should be prepared to expect that the ratios which are below unity do not represent the actual variations of the disturbing influences at those hours quite so purely as do the ratios which are above unity ; and that they are liable to be affected, though in a very subordinate degree, by the abstraction of the neutralized portion, when the aggregate values which they represent are very small. "Without, however, resting undue weight upon this suggestion, we may .safely say that the hours, when the ratios are below unity, are hours of comparative tranquillity, and that their variations from hour to hour are of a far less marked character than during the hours when the ratios exceed unity. Thus viewed, the character of the disturb- ance-diurnal variations may be conceived to have some analogy with that of the phenomena of the regular solar-diurnal variation. We may imagine the disturbance-variation (either the westerly or the easterly, it is indifferent which is taken), — divided as it is into two portions, by the ratios being in the one case above, and in the other below unity, — to correspond in one of its divisions to the hours when the sun is above the horizon, in the part of the hemisphere where the disturb- ance may be imagined to originate, whilst the other division, or that in which the ratios are below unity, and manifest hours of compara- tive tranquillity, may be viewed as the hours of night at the same locality. The solar hours at a station of observation which are characterized by disturbance ratios above unity, will in such case correspond in absolute time with the hours of the day at the sup- 630 posed originating locality, modified (it may be) by a more or less rapid transmission of the disturbance. It will be understood, that in this hypothetical suggestion, the purpose in view is to aid the imagination, if it may be so, in apprehending the ensemble of the phenomena as far as they are yet known to us, rather than to ad- vance a theoretical explanation, when we have not yet sufficient facts before us by which it may be judged ; it may be remarked, however, that the conception of a double locality of origination of the disturb- ances (easterly and westerly) in the one hemisphere will present no especial difficulty to those who are conversant with the general facts of terrestrial magnetism. If our attention be limited to the consideration of the facts observed at a single station, unaccompanied by a view of corresponding pheno- mena elsewhere, we might be in danger of regarding some of the features, particularly perhaps those which are not the most pro- minent, as having an accidental rather than a systematic origin ; and we might thus lose a portion of the instruction which they may otherwise convey. On this account it has appeared desirable to exhibit the phenomena as observed at a second station, in com- parison with those at Kew ; and I have selected for this purpose the results of a similar investigation to the present at Hobarton in Tasmania ; not only because the facts have been remarkably well determined there, but also because, though it is a very distant station, differing widely in geographical latitude and longitude, and situated indeed in a different hemisphere, there is a striking resemblance in the laws of the magnetic storms experienced at both. This resem- blance, which is not only general, but extends to very minute par- ticulars, is such that it seems impossible to resist the impression that the accordance cannot be accidental ; and that the methods of obser- vation and of analysis which have been pursued, have proved themselves well adapted to open to us the knowledge of the existence of system- atic laws, pervading and regulating the action of the forces which are in daily operation around us, and are at least co-extensive with the limits of our globe ; and thus to lead us ultimately to the correct theory of these forces. I have placed therefore beside each other in the next Table the Ratios of Disturbance at the different hours of local solar time at each of the two stations, separating them as before into westerly and easterly deflections, and placing the westerly deflec- 631 tions at Kew in immediate juxtaposition with the easterly at Hobar- ton, and vice versa, as that obviously constitutes the just compari- son. The Hobarton Ratios exhibit the relative prevalence of dis- turbance at the several hours, derived from hourly observations con- tinued for seven years and nine months, viz. from January 1, 1841 to September 30, 1848 ; a series unparalleled in duration at any other of the Colonial Observatories, and which has borne admirably, as I shall hope to have a future opportunity of explaining to the Society, an unquestionable test of its substantial accuracy and fidelity. The number of recorded hourly observations was 56,202, of which 7638 differed from their respective normals of the same month and hour by an amount equalling or exceeding 2'* 13 of arc, and constituted the body of separated observations from which the aggregate values of disturbance at the different hours and their ratios have been obtained. The proportion of disturbed observations thus separated, to the whole body of observations, is about 1 in 7*35 ; differing very little from the proportion already noticed as obtained at Kew by a separating value of 3''3. The disturbing effects due to magnetic storms are therefore somewhat greater at Kew than at Hobarton, though some portion of the difference may be ascribed to the cir- cumstance, that the terrestrial horizontal force, antagonistic to the disturbing forces and tending to retain the magnet in its mean position, is less at Kew than at Hobarton, in the proportion, approx- imately, of 3-7 to 4- 5. 632 TABLE II. — Showing the comparison of the Ratios of the larger Dis- turbances of the Declination at the different hours of local solar time at Kew and Hobarton. Local astronomi- cal hours. KEW. Westerly deflection. HOBARTON. Easterly deflection. KEW. Easterly deflection. HOBARTON. Westerly deflection. Local civil hours. 18 1-85 •18 0-37 0-42 6 A.M. 19 1-83 •75 0-38 0-44 7A.M. 20 1-48 •76 0-36 0-62 8 A.M. 21 1-23 •47 0-38 0-60 9 A.M. 22 1-26 •38 0-33 0-54 10 A.M. 23 1-21 •31 0-39 0-53 11 A.M. 0 •38 •17 0-54 0-67 Noon. 1 •44 •44 0-48 0-56 1 P.M. 2 •53 1-31 0-54 0-68 2 P.M. 3 •71 1-56 0-34 0-60 3 P.M. 4 •35 1-58 0-44 0-50 4 P.M. 5 •15 1-41 0-51 0-42 5P.M. 6 0-94 1-10 0-91 0-68 6 P.M. 7 0-37 0-62 1-19 0-90 7P.M. 8 0-22 0-37 1-56 1-50 8 P.M. 9 0-29 0-22 1-79 1-87 9 P.M. 10 0-20 0-17 2-25 2-20 10 P.M. 11 0-12 0-22 2-38 2-43 11 P.M. 12 0-49 0-38 2-21 2-15 Mid. 13 0-47 0-41 1-98 1-74 1 A.M. 14 0-49 0-53 1-80 1-35 2A.M. 15 0-51 0-71 1-45 1-25 3A.M. 16 0-97 1-01 0-95 0-85 4A.M. 17 1-53 0-96 0-45 0-48 5 A.M. For the convenience of those who prefer graphical illustration, I have represented on an accompanying woodcut the results to which I have referred. The curves drawn in unbroken black lines, in figures 1 and 2, show the phenomena at Kew j those in dotted lines in the same figures, the phenomena at Hobarton. Fig. 1 presents westerly disturbances at Kew, and easterly at Hobarton in comparison with each other ; they are obviously allied phenomena. Fig. 2 presents easterly disturbances at Kew and westerly at Hobarton ; these are also, obviously, allied phenomena, but are as obviously governed by distinct laws from those in fig. 1 . Had the phenomena at Kew and Hobarton been the only ones known to us, we might have inferred that we had obtained the characteristic forms of the diurnal variations due to the action of two distinct and independent forces ; and we might have expected with some degree of confidence to have found curves of corresponding 633 Mean Diurnal Disturbance Variation of the Magnetic Declination. Figs. 1 and 2, Kew and Hobarton. Fig. 3, St. Helena. Local Astronomical Hours. 18 19 20 21 22 23 0 1 23 4 5 67 8 9 10 11 12 13 14 15 16 17 18 Fig. L Kew. Westerly Deflections. ... ~ ^ Hobarton. Easterly Deflections. Hobarton. Westerly Deflections. 1-0 • O'o 18 19 20 21 22 23 0 1 23 45 6 7 89 10 11 12 13 14 15 16 17 18 Local Astronomical Hours. Local Astronomical Hours. 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 0 1 2 34 56 2-5 2-0 10 0-5 Fig. 3. St. Helena. Westerly Deflections. 2-0 l-o 1-0 0-5 7 8 10 11 12 13 14 15 16 17 18 19 20 21 22 23 0 1 23 4 5 Local Astronomical Hours. 634 form by a similar analysis elsewhere ; — and so far experience has been in accord with expectation. But, as the forms of these two pair of curves are not only respectively similar, but as they also correspond in the hours at which their chief characteristic features occur, we might also have formed an inference which would have proved erroneous, viz. that the hours as well as the forms would be the same at other stations. Now this is so far from being in accordance with the facts which we already possess, that whilst the forms present generally a marked resemblance, the hours at different stations exhibit every variety. To exemplify this I have given in a third figure the curve of the westerly disturbance- diurnal variation at St. Helena, of which the form is manifestly the same as that of the two curves in fig. 2, whilst the hours of its most marked features exhibit a difference of nearly 1 2 hours of local time from those in fig. 2. It may not be unsuitable on the present occasion to take a brief retrospective view of the progress of our knowledge respecting these remarkable phenomena, videlicet, the casual magnetic disturbances, or magnetic storms. Antecedently to the formation of the German Magnetic Association and the publication of its first Annual Report in 1837, our information concerning them went no further than that there occurred at times, apparently not of regular recurrence, extra- ordinary agitations or perturbations of the magnetic needle, which had been noticed in several instances to have taken place contempo- raneously in parts of the European continent distant from each other ; and to have been accompanied by remarkable displays of Aurora, seen either at the locality itself where the needle was disturbed, or observed contemporaneously elsewhere. The opinion which appears to have generally prevailed at this time, was that the Aurora and the magnetic disturbances were kindred phenomena, originating pro- bably in atmospherical derangements, or connected at least in some way with disturbances of the atmospherical equilibrium. They were classed accordingly as " Meteorological Phenomena," and were supposed to have a local, though it might be in some instances a wide, extension and prevalence. The special purpose of the German Magnetic Association was to subject the "irregular magnetic disturbances" (as they were then 635 called in contradistinction to the regular periodical and secular varia- tions) to a more close examination, by means of systematized ob- servations made simultaneously in many parts of Germany. With this view, six concerted days in each year were set apart in which the di- rection of the declination-magnet should be observed with great accuracy, by methods then for the first time introduced, at successive intervals of five minutes for twenty-four consecutive hours ; the me- teorological instruments being observed at the same time. The clocks at all the stations were set to Gottingen mean time (Gottingen being the birth-place of the Association), and the observations were thus rendered strictly simultaneous throughout. The high respect entertained for the eminent persons with whom the scheme of the Association originated, obtained for it a very extensive cooperation, not limited to Germany alone, but extending over a great part of the European Continent. The observations of the "Term-days," as they were called, were maintained until 1841, and were all trans- mitted to Gottingen for coordination and comparison. The principal results of this great and admirably conducted co- operative undertaking were published in works well known to mag- neticians. They may be summed up as follows : — The phenomena which were the subjects of investigation were shown to be of casual and not regular occurrence; to prevail contemporaneously everywhere within the limits comprehended by the observations ; and to exhibit a correspondence surprisingly great, not only in the larger, but even in almost all the smaller oscillations ; so that, in the words of the Reporters, MM. Gauss and Weber, " nothing in fact remained which could justly be ascribed to local causes." Equally decided were the conclusions drawn against the previously imagined connexion between the magnetic disturbances and derange- ments of the atmosphere, or particular states of the weather. No perceptible influence whatsoever on the needle appeared to be pro- duced either by wind-storms or by thunder-storms, even when close at hand. The correspondence in the simultaneous movements of the declina- tion-magnet, so strikingly manifested over an area of such wide extent, was however more remarkable in respect to the direction of a per- turbation than to its amount. The disturbances at different stations, and even, as was expressly stated, at all the stations, coincided, even VOL. X. 2 X 636 in the smaller instances, in time and in direction, but with dissimilar proportions of magnitude. Thus it was found generally that by far the greater number of the anomalous indications were smaller at the southern stations and larger at the northern ; the difference being greater than would be due to the difference in the antagonistic retaining force (i. e. the horizontal force of the earth's magnetism, which is greater at the southern than at the northern stations). The generality of this occurrence led to the unavoidable inference, that, in Europe, the energy of the disturbing force must be regarded weaker as we follow its action towards the south. A close and minute comparison of the simultaneous movements at stations in near proximity to each other led to the further conclusion, also stated to be unavoidable, that " various forces must be admitted to be contemporaneously in action, being probably quite independent of each other, and having very different sources ; the effects of these various forces being intermixed in very dissimilar proportions at various places of observation according to the directions and distances of these from the sources whence the perturbations proceed." (Re- sultate aus den Beob. des Mag. Vereins, 1836. pp. 99, 100.) The difficulty of disentangling the complications which thus occur at every individual station was fully foreseen and recognized ; and the Report, which bears the initial of M. Gauss, concludes with the remark that " it will be a triumph of science, if at some future time we should succeed in reducing into order the manifold intricacies of the com- binations, in separating from each other the several forces of which they are the compound results, and in assigning the source and measure of each." Such was the state of the inquiry when it was entered upon by the Royal Society. The Report of the Committee of Physics drawn up (inter alia) for the guidance of the Magnetic Observatories esta- blished by H.M. Government for a limited period in four of the British Colonies, bears date in 1840. The objects proposed by this Report were a very considerable enlargement upon those of the German Association, as well as an extension of the research to more distant parts of the globe. The German observations had been limited for the most part to one only of the three elements required in a complete investigation. When the German Association com- menced its operations, the Declination was the sole element for which 637 an apparatus had been devised capable of recording its variations with the necessary precision. To meet the deficiency in respect to the horizontal component of the magnetic force, M. Gauss constructed in 1837 his bifilar magnetometer, which was employed at Gottingen and at some few of the German stations, concurrently with the Declinometer, in the term observations of the concluding years of the Association. But an apparatus for the corresponding observa- tion of the vertical portion of the Force was as yet wholly wanting ; without such an apparatus as a companion to the bifilar, no deter- mination could be made of the perturbations or momentary changes of the magnetic Dip and Force : and without a knowledge of these no satisfactory conclusion in regard to the real nature, amount and direction of the perturbing forces could be expected. The ingenuity of Dr. Lloyd supplied the desideratum by devising the vertical force magnetometer, which, with adequate care, has been found scarcely, if at all, inferior to the bifilar in the performance of its work. The scheme of the British Observatories was thus enabled to comprehend all the data required for the investigation of the casual disturbances, whether that investigation was to be pursued as before by concerted simultaneous observations at different stations, or, as suggested in the Report, by the determination of the laws, relations and dependencies of the disturbances at individual stations obtained independently and without concert with other observers or other stations. Thus, in reference to these particular phenomena, the British system was both an enlargement and an extension of the objects of the German Asso- ciation ; but it also embraced within its scope the determinations with a precision, not previously attempted, of the absolute values of the three elements, and of the periodical and progressive changes to which they are subject ; premising however, and insisting with a sagacity which has been fully justified by subsequent experience, on the necessity of eliminating in the first instance the effects of the casual and transitory variations, as an indispensable preliminary to a correct knowledge and analysis of the progressive and periodical changes. A further prominency was given to investigations into the particular class of phenomena which form the subject of this paper, by the declaration that " the theory of the transitory changes is in itself one of the most interesting and important points to which the attention of magnetic inquirers can be turned, as they are no doubt intimately connected with the general causes of terrestrial magnetism, 2x2 638 and will probably lead us to a much more perfect knowledge of these causes than we now possess." The instructions contained in the Royal Society's Report for the adjustments and manipulation of the several instruments provided for these purposes were clear, simple and precise. In looking back upon them after the completion of the services for which they were designed, it is impossible to speak of the instructions otherwise than with unqualified praise. But the guidance afforded by the instruc- tions terminated with the completion of the observations. To have attempted to prescribe the methods by which conclusions, the nature of which could not be anticipated, should be sought out from observa- tions not yet made, would have been obviously premature. Yet without some discussion of the results, the mere publication of un- reduced observations is comparatively valueless. It has been well remarked by an eminent authority, whose opinions expressed in the Royal Society's Report have been frequently referred to in the course of this paper, that " a man may as well keep a register of his dreams, as of the weather, or any other set of daily phenomena, if the spirit of grouping, combining, and eliciting results be absent." It was indispensable that the attempt should be made to gather in at least the first fruits of an undertaking on which a considerable amount of public money and of individual labour had been expended ; and the duty of making the attempt might naturally be considered to rest on the person who had been entrusted with the superintendence of the Government Observatories. The methods and processes adopted for reducing, combining, eliminating, and otherwise eliciting results were necessarily of a novel description ; they were in fact an endeavour to find a way by untrodden paths to simple and general phenomenal laws where no definite knowledge of the origin or mode of causation of the phenomena previously existed. Happily it is not necessary to trespass on the time or attention of the Society by a description of the methods and processes which have been employed to elucidate some of the leading features of the magnetic storms, as these are fully described in the discussions prefixed to the ten large volumes in which the observations at the Colonial Observatories have been printed. It will be only necessary to advert, and that very briefly, to some of the principal conclusions which may be supposed to throw most light on the theory of these phenomena. The results of the extension of the term-day comparisons to the 639 American Continent, and to the Southern Hemisphere and the Tropics, may first be disposed of in a very few words. The contem- poraneous character of the disturbances, which had been shown by the German term-observations to extend over the larger portion of the European Continent, manifested itself also in the comparisons of the term-days in 1840, 1841, and 1842 at Prague andBreslau in Europe, and Toronto and Philadelphia in America, published in 1845; and the same conclusion was obtained by comparing with each other the term-days at the Colonial Observatories, situated in parts of the globe most distant from one another. The days of disturbance still appeared to be of casual occurrence, but were now recognized as affections com- mon to the whole globe, showing themselves simultaneously at stations most widely removed from each other. When distant stations were compared, as for example stations in Europe with those in America, and either or both with Tasmania, discrepancies in the amount of par- ticular perturbations, similar to those which had been found in com- paring the European stations with each other, presented themselves, but larger and more frequent, and extending occasionally even to the reversal of the direction of the simultaneous disturbance. Instances were not unfrequent of the same element, or of different elements, being disturbed at the same observation-instant in Europe and America ; and on the other hand, there were perturbations, sometimes of considerable magnitude, on the one continent, of which no trace was visible on the other. Hence it was concluded, with the increased confidence due to this additional and more extensive experience, that various forces proceeding from different sources were contem- poraneously in action; and it was further inferred that the most suitable and promising mode of pursuing the investigation was by an endeavour to analyse the effects produced at individual stations, and to resolve them if possible into their respective constituents. The hourly observations which had been commenced at the Colonial stations in 1841 and 1842, and continued through several subsequent years, furnished suitable materials for this investigation, the first fruits of which were the discovery, that the disturbances, though casual in the times of their occurrence, and most irregular when individual perturbations only were regarded, were, in their mean effects, strictly periodical phenomena ; conforming in each element, and at each station, on a mean of many days, to a law de-* 640 pendent on the solar hour ; thus constituting a systematic mean diurnal variation distinct from the regular daily solar-diurnal variation, and admitting of being separated from it by proper processes of reduction. This conformity of the disturbances to a law depending on the solar hours was the first known circumstance which pointed to the sun as their primary cause, whilst at the same time a difference in the mode of causation of the regular- and of the disturbance-diurnal variations seemed to be indicated by the fact, that in the disturbance- variation the local hours of maximum and minimum were found to vary (apparently without limit) in different meridians, in contrast to the general uniformity of those hours in the previously and more generally recognized regular solar-diurnal variation. This first reference of the magnetic storms to the sun as their primary cause, was soon followed by a far more striking presumptive evidence of the same, by a further discovery of the existence of a periodical variation in the frequency of occurrence; and amount of aggregate effects, of the magnetic storms, corresponding in period, and coincident in epochs of maximum and minimum, with the de- cennial variation in the frequency and amount of the spots on the sun's disk, derived by Schwabe from his own systematic observations commenced in 1826 and continued thenceforward. The decennial variation of the magnetic storms is based on the observations of the four widely distributed Colonial Observatories, and is concurred in by all. This remarkable correspondence between the mag- netic storms and physical changes in the sun's photosphere, of. such enormous magnitude as to be visible from the earth even by the unassisted eye, must be held to terminate altogether any hypo- thesis which would assign to the cause of the magnetic disturbances a local origin on the surface or in the atmosphere of our globe, or even in the terrestrial magnetism itself, and to refer them, as cos- mica! phenomena, to direct solar influence ; leaving for future solu- tion the question of the mode in which that influence produces the effects which we believe we have thus traced to their source in the central body of our system*. * The existence of a decennial period of the magnetic storms was not, as some have supposed, a fortuitous discovery ; but a consequence of a process of exami- nation early adopted^and expressly devised, by the employment of a constant sepa- rating value, to make known any period of longer or shorter duration which might 641 We may regard as a step towards this solution the separation of the disturbances of the declination into two distinct forces acting in different directions and proceeding apparently from different foci; the phenomena of distinct (though in so many respects closely allied) variations exhibit the same peculiar features at all the stations to which the analysis has hitherto extended, and have been exemplified by the observations at Kew, as shown in the early part of this paper. A similar separation into two independent affections, each having its own distinct phenomenal laws, has followed from an analysis of the same description applied to the disturbances of the magnetic dip and force at the Colonial stations ; thus placing in evidence, and tracing the approximate laws of the effects of six distinct forces (two in each element) contemporaneously in action in all parts of the globe, and pointing in no doubtful manner to the existence of two terrestrial foci or sources in each hemisphere from which the action of the forces emanating from the sun and communicated to the earth may be con- ceived to proceed. Such an ascription naturally suggests to those conversant with the facts of terrestrial magnetism the possibility that Halley's two terrestrial magnetic foci in each hemisphere may be either themselves the localities in question, or may be in some way intimately connected with them. The important observations which we owe to the zeal and devotion of Captain Maguire, R.N. and ths Officers of H.M.S. ' Plover/ have made us acquainted with Point Bar- row as a locality where the magnetic disturbances prevail with an energy far beyond ordinary experience, indicating the proximity of that station to the source or sources from which the action of the forces may proceed. Now Point Barrow is situated in a nearly inter- mediate position between what we believe to be the present localities of fall within the limits comprised by the observations. The period being decennial, and the epoch of minimum occurring at the end of 1843 or beginning of 1844, the epoch of maximum was necessarily waited for in order to ascertain the precise duration of the cycle. The maximum took place in 1848-1849, the observations in 1850 and 1851 showing that the aggregate value of the annual disturbances was again diminishing as it had been in 1842 and 1843. The process of deter- mining the proportion of disturbance in different years is a somewhat laborious one, and requires time : but in March 1852, I was able to announce to the Royal Society the existence of a decennial variation, based on the concurrent testimony of the observations at Toronto and Hobarton ; deeming it proper that so remark- able a fact should not be publicly stated until it had been thoroughly assured by independent observations at two very distant parts of the globe. 642 Halley's northern foci, and at no great distance from either : in such a situation the exposure to disturbing influences proceeding from both might well be supposed to be very great. The displays of Aurora at Point Barrow exceed also in numerical frequency any record received from any other part of the globe. The further prosecution of this investigation appears to stand in need of some more systematic proceeding than would be supplied by the uncombined efforts of individual zeal. Observations similar to those of the Kew Observatory, made at a few stations in the middle latitudes of the hemisphere, distributed with some approach to symmetry in their longitudinal distances apart, would probably fur- nish data, which by their combination might serve to assign the localities from whence the disturbances are propagated — contribute still further to disentangle the complications of the forces which pro- duce them, — and thus hasten the attainment of that " triumph of science" foreseen and foreshadowed by the great geometrician of the last age. Of such a nature was the scheme contemplated by the Joint Committee of the Royal Society and British Association, and submitted to H.M. Government in the hope of obtaining their aid in the execution of such part of it as fell within British dominion ; and of thus " maintaining and perpetuating our national claim to the furtherance and perfecting of this magnificent depart- ment of physical inquiry." (Herschel in * Quarterly Review,' September 1840, p. 277.) The scheme was no unreasonable one: probably eight or nine stations in the contour of the hemisphere might suffice ; and of these we already possess the observations at Toronto ; those at Kew are in progress ; and self-recording instru- ments, similar to those at Kew, are now under verification at Kew pre- paratory to being employed on the Western or Pacific side of the United States Territory, at a point not far from the previously desired Station of Vancouver Island, for which a substitute is thus provided. This Observatory, as well as one at Key West on the southern coast of the United States, in which self-recording instruments are already at work, will be maintained under the authority and at the expense of the American Government, and both have been placed under the superintendence of the able and indefatigable director of the " Coast Survey," Dr. Alexander Dallas Bache. The Russian Observatory at Pekin, the trustworthy observations of which are already known to 643 the Society, is understood to have recommenced its hourly observa- tions, and stands only in need of an apparatus for the vertical force (which might be readily supplied from this country), to contribute its full complement to the required data. More than half the stations may therefore be regarded as already provided for, and there are other Russian observatories in the desired latitudes and longitudes which might be completed with instruments for a full participation. It would be wrong to conclude these imperfect notices without recognizing how greatly the researches have been aided in their progress by the united and unfailing countenance and support of the Royal Society and of the British Association. The Kew Observatory owes its existence and maintenance to funds most liberally supplied from year to year by the British Association ; and the cost of the self-recording magnetic instruments, of which the first instalment of the results has formed the early part of this paper, was supplied from funds at the disposal of the Council of the Royal Society. Mag- netical science, rapidly as it is advancing, is even yet in its infancy ; and it is in their early stages particularly that all branches of natural knowledge stand in need of the fostering aid of societies in which science is valued and cultivated for its own sake. November 22, 1860. Major-General SABINE, R.A., Treasurer and Vice-President, in the Chair. John Thomas Quekett, Esq., was admitted into the Society. In accordance with the Statutes, notice was given of the ensuing Anniversary Meeting, and the list of Council and Officers proposed for election was read as follows : — President. — Sir Benjamin Collins Brodie, Bart., D.C.L. Treasurer. — Major-General Edward Sabine, R.A., D.C.L. f William Sharpey, M.D., LL.D. Secretaries. — « _, -,,.,01 -^ UTAT^^T I George Gabriel Stokes, Esq., M.A., D.C.L. Foreign Secretary. — William Hallows Miller, Esq., M.A. Other Members of the Council. — John Couch Adams, Esq. ; Sir 644 John Peter Boileau, Bart. ; Arthur Cayley, Esq. ; William Fairbairn, LL.D.; Hugh Falconer, M.D.; William Farr, M.D., D.C.L.; Thomas Graham, Esq., M.A., D.C.L. ; Sir H. Holland, Bart., M.D., D.C.L.; Thomas Henry Huxley, Esq.; Sir J. G. Shaw Lefevre, M.A., D.C.L. ; James Paget, Esq. ; Joseph Prestwich, Esq. ; William Spottis- woode, Esq., M.A.; JohnTyndall, Ph.D.; Alex. William Williamson, Ph.D. ; Col. Philip Yorke. The following communications were read : — I. "On Boric Ethide." By EDWARD FRANKLAND, Ph.D., F.R.S., and B. DUPFA, Esq. (See p. 568.) II. " On Cyanide of Ethylene and Succinic Acid." — Preliminary Notice, By MAXWELL SIMPSON, Ph.D. (See p. 574.) III. "Results of Researches on the Electric Function of the Torpedo." By Professor CARLO MATTEUCCI of Pisa. In a Letter to Dr. SHARPEY, Sec. R.S. (See p. 576.) IV. "Natural History of the Purple of the Ancients." By M. LACAZE DUTHIERS, Professor of Zoology in the Faculty of Sciences of Lille. (See p. 579.) V. " Contributions towards the History of Azobenzol and Ben- zidine." By P. W. HOFMANN, Ph.D. (See p. 585.) VI. " On Bromphenylamine and Chlorphenylamine." By E. T. MILLS, Esq. (See p. 589.) VII. "New Compounds produced by the substitution of Ni- trogen for Hydrogen." By P. GRIESS, Esq. (See p. 591.) VIII. " Contributions towards the History of the Monamines." — No. III. Compound Ammonias by Inverse Substitution. By A. W. HOFMANN, LL.D., F.R.S. &c. (See p. 594.) IX. " Notes of Researches on the Poly- Ammonias/' — No. IX. Remarks on anomalous Vapour-densities. By A. W. HOF- MANN, LL.D., F.R.S. &c. (See p. 596.) X. "Notes of Researches on the Poly-Ammonias." — No. X. 645 On Sulphamidobenzamine, a new base ; and some Remarks upon Ureas and so-called Ureas. By A. W. HOFMANN, LL.D., F.R.S. &c. (See p. 598.) XI. st Researches on the Phosphorus-Bases.3' — No. VIII. Oxide of Triethylphosphine. By A. W. HOFMANN, LL.D., F.R.S. &c. (See p. 603.) XII. " Researches on the Phosphorus-Bases." — No. IX. Phos- pharsonium Compounds. By A. W. HOFMANN, LL.D., F.R.S. &c. (See p. 608.) XIII. " Researches on the Phosphorus-Bases." — No. X. Meta- morphoses of Bromide of Bromethylated Triethylphos- phonium. By A. W. HOFMANN, LL.D., F.R.S. &c. (See p. 610.) XIV. ' e Researches on the Phosphorus-Bases." — No. XI. Ex- periments in the Methyl- and in the Methylene- Series. By A. W. HOFMANN, LL.D., F.R.S. &c. (See p. 613.) XV. " Researches on the Phosphorus-Bases." — No. XII. Rela- tions between the Monoatoinic and the Polyatomic Bases. By A. W. HOFMANN, LL.D., F.R.S. &c. (See p. 619.) XVI. " On the Physiological Anatomy of the Lungs." By JAMES NEWTON HEALE, M.D. Communicated by Sir B. C. BRODIE, Bart., P.R.S. Received August 28, 1860. (Abstract.) The arrangement observed in the divisions and subdivisions of the bronchial tube is that of a panicle. There is everywhere to be di- stinguished a straight diminishing tube, from which lesser tubes are given off alternately from its sides ; these lesser tubes in their turn observe a similar plan of distribution, and the smaller tubes, down to their ultimate terminations, are governed by the same system. There is nowhere to be found either a true dichotomous or a trichotomous division. The distinction between that part which is bronchial tube and that which is parenchyma, is, in a properly injected lung, marked and very decisive, and can never be mistaken by even the most inex- 646 perienced person, when a fragment, however small, is examined by the microscope. When the bronchial tubes have reached their penultimate termi- nations, the coats which form their perimeters split, as it were, into two layers. The outer of these, which is tougher, thicker, and more fibrous, expands and encloses an ultimate portion of the parenchyma. To these portions of the lung the name of * leaflets ' is given in this treatise. The outer coat of the bronchial tube, by being spread out in the leaflets, becomes continuous with the general parenchyma of the lungs. The inner portion of the tube immediately divides into nu- merous minute tubes, to which the name of ' pedicels * is now given. Each of the pedicels goes to a different leaflet, but each leaflet receives several pedicels from different terminal bronchial tubes. A minute anastomosis is thereby established between the termina- tions of the different bronchial tubes, through the leaflets. On entering the leaflet, each pedicel splits up into processes which ex- tend to the internal perimeter of the leaflet, and by intersections with similar processes derived from the other pedicels, divide the interior into compartments called c air-cells.' Each leaflet is, to a considerable extent, divided from those which surround it by sulci, but it is continuous in structure with them by certain parts of its base, in which it is in contact with them and adherent. On the surface of the lungs these leaflets give the appearance of bodies of a somewhat quadrilateral shape. The interior of all the bronchial tubes is marked with 'rugae,' and these rugae show the direction of the bundles of longitudinal con- tractile fibres, which are placed immediately beneath the mucous membrane. These longitudinal fibres are surrounded by circular ones, and it is by the contraction of these latter that the rugae are formed. When the bronchial tubes have been kept distended, the rugae are not present ; the mucous membrane is then perfectly smooth. There are no such things as f alveoli ' belonging to the tube. The bronchial artery supplies the following structures : — I. The successive layers of cellular tissue, the lymphatic glands, coats of the pulmonary vessels, neurilemma, &c. II. The fibre-cartilaginous and fibrous portion of the bronchial tubes ; some exceedingly minute capillaries, derived from these, ex- 647 tend into the mucous membrane, but do not in any way anastomose with the proper vascular plexus belonging to this structure. III. The bronchial artery also freely supplies the walls and pro- cesses of the leaflets with arterial blood. IV. Some small branches arrive at the surface of the lungs, being conducted thither by some minute bronchial tubes, which communi- cate with longitudinal air-passages to be found in the substance of the pleura. These small arteries anastomose freely with other branches of the same artery in the sub-pleural cellular tissue. The bronchial artery forms no sort of anastomosis with the pul- monary system in any part of the lungs, and is quite incapable of dis- charging the function of the latter under any circumstances whatever. The bronchial veins are of two sorts : one forms a very free system of inosculation on the surface of the lungs, the other is always dis- coverable (in the recent lung) in the loose cellular tissue surrounding the bronchial tubes : they both have valves, and consequently cannot be injected in a retrograde direction, but they can both be injected from the bronchial artery. Neither of them can be injected under any circumstances from the pulmonary system. They both have large intercommunicating trunks. The pulmonary artery accompanies the bronchial tube, dividing precisely as it divides ; wherever there is a bronchial tube, however small, there is likewise a corresponding pulmonary artery, and never more than one. It gives off no branches to any collateral structure, and it forms no inosculations either with its own branches or with any other vessels ; every portion of it ultimately reaches the leaflets, and there it makes a most minute, uniform and equal reticulation, anastomosing throughout the lung. The pulmonary vein commences by tufts in the interior of the leaflets ; part of the capillary vessels emerges on to the surface of the leaflet, and commences the formation of minute veins, which imme- diately dip down through the sulci which divide the leaflets, to reach the interlobular surfaces, where they increase in size, and ultimately come into contact with the under surface of a bronchial tube : the other part of the capillary vessels makes its way from the interior of the leaflet by means of the pedicel, and reaches the mucous mem- brane, where a most abundant, minute, and exceedingly regular plexus is formed, occupying the whole surface of the mucous membrane. 648 This plexus in the larger tubes is reinforced by blood-vessels derived from numerous leaflets which surround the bronchial tubes ; straight vessels penetrate from these leaflets through the walls of the bronchial tubes, to reach the plexus in the mucous membrane. On the external surface of the bronchial tubes, numerous radiating vessels collect the blood from the plexus in the mucous membrane, and the trunks of these radiating vessels soon terminate in the veins, already described as coming into contact with the under surface of the bronchial tube. The vessels which have been alluded to as receiving their tri- butaries in the interlobular surfaces, collect their blood from all the surrounding lobules ; consequently the blood which reaches the vein placed in contact with a particular bronchial tube, is not derived exclusively from the same lobules as those with which that bronchial tube and its accompanying artery are in connexion, but it receives its blood from all parts of the lungs promiscuously. The pulmonary veins accompanying the bronchial tubes continue to increase in size in proportion as the tubes themselves increase, and finally they terminate in the large veins which enter the left auricle. XVII. " On the Curvature of the Indian Arc." By the Vene- rable J. H. PRATT, Archdeacon of Calcutta. Communicated by Prof. STOKES, Sec. U.S. Received Sept. 3, I860. (Abstract.) This communication completes the series of the author's papers on the subject of the Indian Arc. He commences by recapitulating the chief results of his former calculations, and adverting to the at- tempt which he made in his former papers to explain the difficulty which those calculations brought to light, namely, that the ampli- tudes of the arcs from Kaliana to Kalianpur and from Kalianpur to Damargida, determined geodetically, were so little in excess as they proved to be of the same amplitudes determined astronomically, — a difficulty which he endeavoured to get over by attributing to the Indian Arc a curvature different from that corresponding to the mean meridian of the earth. In the present communication, introducing the condition that the length of the chord of the arc must be the same in both the ellipses, the local and the mean, drawn through the 649 stations at the extremities of the arc, he demonstrates that no change in the curvature of the arc, within reasonable and indeed within wide limits, can have any appreciable effect on the calculated am- plitude. The author's conclusions from the whole investigation re- garding the Indian Arc are thus summed up : — (1) Colonel Everest discovered that the astronomical amplitudes of the two portions of the Indian Arc between Kaliana and Kalianpur, and between Kalianpur and Damargida, are, the first less by 5" -24, and the second greater by 3"'79, than the geodetic amplitude calcu- lated with the mean semi-axes and ellipticity of the earth. (2) The geodetic amplitudes of these two portions of the arc, calculated from the measured lengths and with the mean axes, will be sensibly exact, even should the curvature of the arc differ from that of the mean meridian within reasonable but wide limits — a thing which geology teaches us to be very likely the case. (3) Hence the geodetic measurements of the survey being without sensible error, as is known by the tests applied, the discrepancy in (1) can only arise from local attraction affecting the vertical line, and so changing the astronomical amplitudes. (4) Two great visible causes of disturbance of the vertical by at- traction are, the Mountain Mass on the north of India, and the Ocean on the south. The influence of both of these is felt all over India ; the first producing a northerly deflection, varying from 2 7"' 9 8 at Kaliana to a sensible angle (probably about 3", but this the author has not calculated) at Cape Comorin ; the second producing also a northerly deflection, varying from about 19"' 71 at Cape Comorin to 6"* 18 at Kaliana. (5) The combined effect of these two visible causes is to make the astronomical amplitude of the upper arc 13"'l 1 too small, and of the lower 3"f82 also too small. They are therefore insufficient to ac- count for the discrepancies pointed out by Colonel Everest. Some other cause must exist tending to increase the upper astronomical am- tude by 13"'ll — 5"'24=7"'87, and also to increase the lower am- plitude by 3"-82 + 3"-79=7"'61. (6) It has been demonstrated that a slight but wide-spread varia- tion in the density of the crust, from that deduced from the fluid- theory, either in excess or defect, such as there is no difficulty in conceiving to exist, is sufficient to account for deflections such as 650 these. For example : an excess of density amounting only to part, extending through a circuit of about 120 miles around the mid-point of the whole arc between Kaliana and Damargida (and therefore not far from Kalianpur), and to a depth of about 200 miles, will produce this effect, and make the calculated deflections from the three causes — the mountains, the ocean, and this hidden cause below — exactly accord with the observed errors in the astronomical ampli- tudes. (7) The resulting total deflections at Kaliana, Kalianpur, and Da- margida, arising from the three causes, are 2 6"* 29, 21 "'05, and 24"-84 : these make the two astronomical amplitudes, the one 5"' 24 smaller, and the other 3" '79 larger than the geodetic amplitudes, the error brought to light by Colonel Everest. (8) No error can arise in the mapping of India by using the geo- detic measurements. But the position of any places put into the map thus formed, the latitudes of which are determined from observations of the sun or any other heavenly body, will be wrong by the total amount of the deflection at those places, amounting in the three cases above to as much as half a mile. INDEX TO VOL. X. , cutaneous, experi- ments on the influential circumstances of, 122. Acetic acid, on the synthesis of, 4. Acids, behaviour of aldehydes with, 108. Addison (W.) on the effects produced in human blood-corpuscles by sherry wine, 186. Air-currents, on the producing forces of, 235. Aldehydes, behaviour of, with acids, 108. Alkaloids, new volatile, given off during putrefaction, 341. Alloys, specific gravity of, 12. , on the electric conducting power of, 205 ; on the specific gravity of,' 207 ; on the expansion of, 315. Amalgams, conductivity of, 14. Andrews (T.) on the volumetric rela- tions of ozone and the action of the electrical discharge on oxygen and other gases, 427. Anniversary Meeting, Nov. 30, 1859, 160, i. Annual Meeting for election of Fellows, June 1859, 95 ; June 1860, 494. Aqueous vapour, relations between the elastic and motive force of, 461. Arc, on the curvature of the Indian, 197, 648. Arithmetical progressions, propositions upon, 1. Attraction of solids, on the analytical theory of, bounded by surfaces of a class including the ellipsoid, 181. Azobenzol, contributions towards the history of, 585. Babbage (C.), observations on the dis- covery in various localities of the re- mains of human art mixed with the bones of extinct races of animals, 59. liobington (B. G-.) on spontaneous evaporation, 127. I'.ache (A. P.), elected foreign member, 473. Bakerian Lecture. — Experimental re- VOL. X. searches to determine the density of steam at all temperatures, and to de- termine the law of expansion of super- heated steam, 469. Beale (L. S.) on the distribution of nerves to the elementary fibres of striped muscle, 519. Belgium, severe thunder-storm in, 359. Belper (Lord Edward), election of, 404. Bentham (GK), Eoyal Medal awarded to, 176. Benzidine, contributions towards the history of, 585. Benzylic alcohol, on a new homologue of, 298. Blakiston (Capt.), account of a remark- able ice shower, 468. Blood-corpuscles, effects produced in, by wine, 186. Boiling-point, the relation between it and composition in organic compounds, 463. Boric ethide, on, 568. Brayley (E. W.), notes on the apparent universality of a principle analogous to regulation, on the physical nature of glass, and on the probable existence of water in a state corresponding to that of glass, 450. Brewster (Sir D.) on the lines of the solar spectrum, 339. Bright (R.), obituary notice of, i. Brodhurst (B. E.) on the repair of tendons after their subcutaneous di- vision, 196. Broderip (W. J.), obituary notice of, iv. Brodie (B. C.) on the atomic weight of graphite, 11. Bromethylated triethy Iphosphonium , metamorphoses of bromide of, 610. Bromphenylamine, on, 589. Bronchial vessels, distribution of, in human lung, 22 ; communication with pulmonary vessels, 24. Broun (J. A.) on the lunar-diurnal variation of magnetic declination at the magnetic equator, 475. Brown -Sequard (E,), hereditary trans- 2 Y 652 INDEX. mission of an epileptiforrn affection accidentally produced, 297. Brown-Sequard (E.), experimental re- searches on various questions concern- ing sensibility, 510. Brunei (I. 3L), obituary notice of, vii. Bunsen (R. W.), photo-chemical re- searches (Part IY.), 39. Calculus of operations, on an extended form of the index symbol in, 207. Calculus of probabilities, application of, to results of measures of the position and distance of double stars, 133. Calorimeter, a new, for determining the radiating powers of surfaces, 514. Caoutchine, on, 516. Carpenter (W. B.), researches on the Foraminifera (Fourth and conclu- ding series), 506. Cartmell (R.) on the behaviour of al- dehydes with acids, 108. Caves, observations on the discovery of remains of human art and bones in, 60. Cayley (A.), Royal Medal awarded to, 173. on the equation of differences for an equation of any order, and hi particular for the equations of the orders two, three, four, and five, 428. on the theory of elliptic motion, 430. Chlorphenylamine, on, 589. Chowne (W. D.) on the relations between the elastic force of aqueous vapour at ordinary temperatures, and its motive force in producing currents of air in vertical tubes, 461. Colour-blindness, remarks on, 72. Compass, deviations of, in wood-built andiron-built ships in the Royal Navy, 538. Compound colours, theory of, 404, 484. Copley Medal awarded to W. E. Weber, 172. Copper, electric conductivity of, effect of metals and metall oids on, 460. -, electric conductivity in wires of, 300. Crace-Calvert (F.) on the conductivity of mercury and amalgams, 14. on the expansion of metals and alloys, 315. on some new volatile alkaloids given off during putrefaction, 341. Croonian Lecture. — On the arrangement of the muscular fibres of the ventricu- lar portion of the heart of the mam- mal, 433. Darnell's battery, measurement of elec- trostatic force produced by, 319. Darkness, influence of, on animals, 184. Davy (J.) on the electrical condition of the egg of the common fowl, 31. De Grey and Ripon (Earl), election of, 473. De la Rive (A., For. Mem.), admission of, 433. De la Rue (W.) on the resin of the Ficus rubiginosa, and a new homologue of benzylic alcohol, 298. De Verneuil (P. E. P.), elected foreign member, 473. Diabetes, production of, by lesions of the nervous system, 27. Diatomic ammonias, 224. Dirichlet (P. Gr. L.), obituary notice of, xxxviii. Dobell (H.), supplement to a paper read Feb. 17, 1859, on the influence of white light, of the different coloured rays and of darkness, on the develop- ment, growth, and nutrition of ani- mals, 184. Donkin (W. F.) on the analytical theory of the attraction of solids bounded by surfaces of a class including the ellip- soid, 181. Double stars, application of calculus of probabilities to measures of, 133. Duppa (B.) on boric ethide, 568. Ear, mode in which sonorous undula- tions are conducted from the mem- brana tympani to the labyrinth, 32. Earthquake in the kingdom of Naples, 16th of December 1857, report on, 486. Electric conductivity, attempt to ascer- tain cause of differences of, in copper wires, 300. discharge through rarefied gases and vapours, 256. Electrical discharge in vacua with an ex- tended series of the voltaic battery, 36. , action of, on ozone and other gases, 427. , vacua indicated by, 274. discharges, application of, to pur- poses of illumination, 432. Electrolytes, movements of, in the vol- taic circuit, 235. Electromotive force required to produce a spark in air between parallel metal plates at different distances, measure- ment of, 326. Electrostatic force produced by a Darnell's battery, 319. INDEX. 653 I Elefanti (F.), propositions upon arith- metical progressions, 1. , problem on the divisibility of numbers, 208. Elliptic functions, on a new method of approximation applicable to, 474. Elliptic motion, on the theory of, 430. Ellis (A. J.) on the laws of operation, and the systematization of mathe- matics, 85. — — on scalar and clinant algebraical coordinate geometry, introducing a new and more general theory of ana- lytical geometry, including the re- ceived as a particular case, and ex- plaining ' imaginary points,' ' inter- sections,' and ' lines,' 415. Epileptiform affection, hereditary trans- mission of an accidental, 297. Equation of differences for an equation of any order, 428. Ethylamine, new derivatives of, 104. Ethylene, cyanide of, 574. Evans (F. J.), reduction and discussion of the deviations of the compass ob- served on board of all the iron-built ships and a selection of the wood- built steam-ships in H.M. Navy, and the iron steam- ship ' Great Eastern ; ' being a report to the Hydrographer of the Admiralty, 538. Evaporation, spontaneous, 127. Eyes, focal power of, for horizontal and vertical rays, 381. Fairbairn (W.) on the resistance of glass globes and cylinders to collapse from external pressure, and on the tensile and compressive strength of various kinds of glass, 6. , experimental researches to deter- mine the density of steam at all tem- peratures, and to determine the law of expansion of superheated steam, 469. Faraday (M.), note on regelation, 440. Ficus rubiginosa, on the resin of, 298. FitzEoy (R.)j remarks on the late storms of Oct. 25-26 and Nov. 1, 1859, 222. , notice of the ' Royal Charter Storm' in October 1859, 561. Flint-implements in gravel, 50. Fluids in motion, on the thermal effects of, 502, 519. Foraminifera, researches on, 506. Foster (M.) on the effects produced by freezing on the physiological proper- ties of muscles, 523. Frankland(E.) on boric ethide, 568,614. Franklin Expedition, report of scientific researches made during search for the, 148. Gaseous bodies, transmission of radiant heat through, 37. Gases and vapours, electric discharge through, 256. Gassiot (J. P.) on the electrical dis- charge in vacua with an extended series of the voltaic battery, 36. on the interruption of the voltaic discharge in vacua by magnetic force, 269. on vacua as indicated by the mer- curial siphon-gauge and the electrical discharge, 274. on the luminous discharge of vol- taic batteries, when examined in car- bonic acid vacua, 393. on the application of electrical discharges from the induction coil to the purposes of illumination, 432. Gasteropodous mollusca, on the circula- tion of, 193. Geometry, analytical, new general theory of, 415. Geuther (A.) on the behaviour of the aldehydes with acids, 108. Gladstone (J. H.) on the lines of the solar spectrum, 339. Glass, tensile and compressive strength of, 6. , resistance of, to collapse from external pressure, 6 ; from internal pressure, 8. , on the physical nature of, 450. Glycol, on the action of acids on, 114. Gore (G.) on the movements of liquid metals and electrolytes in the voltaic circuit, 235. Graphite, atomic weight of, 11. Griess (P.) on a new method of sub- stitution, and on the formation of iodobenzoic, iodotoluylic, and iodanisic acids, 309. , new compounds produced by the substitution of nitrogen for hydrogen. 591, 644. Gutta percha, insulating properties of, 409. Hallam (H.), obituary notice of, xii, Harley (G.) on the saccharine function of the liver, 289. Hassall (A. H.) on the frequent occur- rence of phosphate of lime in the cry- stalline form in human urine, and on its pathological importance, 281. Heale (J. N.) on the physiological ana- tomy of the lungs, 645. 2 Y2 654 INDEX. Heart, arrangement of muscular fibres of, 433. Helmholtz (H.), elected foreign member, 473. Henfrey (A..) on the anatomy of Vic- toria Regia, 14. , obituary notice of, xviii. Herschel (Sir J. F. W.), remarks on colour-blindness, 72. on the formula investigated by Dr. Brinkley, for the general term in the development of Lagrange's ex- pression for the summation of series and for successive integration, 500. Hicks (J. B.) on certain sensory organs in insects, 25. Hofmann (A. W.), notes of researches on the poly-ammonias : No. VI. new derivatives of phenylamine and ethyl- amine, 104 ; No. VII. on the diatomic ammonias, 224 j No. VIII. action of nitrous acid upon nitrophenylene- diamine, 495 ; No. IX. remarks on anomalous vapour-densities, 596, 644; No. X. on sulphamidobenzamine, a new base ; and some remarks upon ureas and so-called ureas, 598, 644. , researches on the phosphorus bases : No. VI., 100; No. VII. triphospho- nium compounds, 189 ; No. VIII. oxide of triethylphosphine, 603, 645; No. IX. phospharsonium compounds, 608, 645 ; No. X. metamorphoses of bromide of bromethylated triethyl- phosphonium, 610, 645 ; No. XL ex- periments in the methyl and in the methylene-series, 613, 645 ; No. XII, relations between the monoatomic and the polyatomic bases, 619, 645. , contributions to the history of the phosphorus bases, Parts I., II., III., 568, 644. , contributions towards the history of the monamines : No.III. compound ammonias by inverse substitution, 594. , researches on the nitrogen bases, 621. Hofmann (P. W.), contributions towards the history of azobenzol and benzidine, 585, 644. Holzmann (M.) on the effect of the pre- sence of metals and metalloids upon the electric conductivity of pure cop- per, 460. Hopkins (T.) on the forces that pro- duce the great currents of the air and of the ocean, 235. Hopkins (W.) on the construction of a new calorimeter for determining the radiating powers of surfaces, and its application to the surfaces of various mineral substances, 514. Horsfield (T.), obituary notice of, xix. Howard de Walden (Lord), letter on a recent severe thunder-storm in Bel- gium, 359. Humboldt (A. von), obituary Notice of, xxxix. Ice, account of a remarkable shower of, 468. , theories and experiments at or near melting-point of, 152. Insects, sensory organs in, 25. Insulating bodies, electric properties of, 2. lodobenzoic acid, new method of sub- stitution and formation of, 309. lodotoluylic acid, new method of sub- stitution and formation of, 309. Isoprene, on, 516. Jenkin (F.) on the insulating properties of gutta percha, 409. Johnson (M. J.), obituary notice of, xxi. Jones (T. W.), analysis of my sight, with a view to ascertain the focal power of my eyes for horizontal and for vertical rays, and to determine whether they possess a power of ad- justment, 381. Joule (J. P.) on the thermal effects of fluids in motion, 502 ; temperature of bodies moving in air, 519. Kolliker(A.) on the frequent occurrence of vegetable parasites in the hard structures of animals, 95. on the structure of the chorda dorsalis of the Plagiostomes and some other fishes, and on the relation of its proper sheath to the development of the vertebra, 214. , elected foreign member, 473. Kopp (H.) on the relation between boiling-point and composition in or- ganic compounds, 463. Lacaze-Duthiers (F. J. H.), note re- specting the circulation of gasteropo- dous Mollusca and the supposed aqui- ferous apparatus of the Lamellibran- chiata, 193. , natural history of the purple of the ancients, 579, 644. Lamellibranchiata, on the supposed aquiferous apparatus of, 1S3. Lawes (J. B.) on the sources of the nitrogen of vegetation ; with special INDEX. 655 reference to the question whether plants assimilate free or uncombined nitrogen, 544. Light, influence of different coloured rays of, on animals, 184. , radiated by heated bodies, 385. , nature of, emitted by heated tour- maline, 503. Liquid metals, movements of, in the voltaic circuit, 235. Liver, on the saccharine function of, 289. , on the alleged sugar-forming func- tion of, 528. Lowe (E. J.), a new ozone-box and test- slips, 531. on the temperature of flowers and leaves of plants, 534. Lowe (G. C.) on the expansion of metals and alloys, 315. Lung, human, intimate structure of, 16 ; distribution of blood-vessels of, 21. Lungs, physiological anatomy of, 645. M'Cliutock (F. L.), report of scientific researches made during the late Arc- tic voyage of the yacht ' Fox ' in search of the Franklin Expedition, 148. Magnetic declination, solar- diurnal va- riation of, at Pekin, 360 ; lunar-diur- nal variation "of, 475. Magnetic declination at Kew, laws of the phenomena of the larger disturbances of, 624. Magnetic force, its interruption of the voltaic discharge in vacua, 269. Magnetic storms, increased knowledge of, 624, 634. Mallet (B.), report to the Royal Society of the expedition into the kingdom of Naples to investigate the circum- stances of the earthquake of the 16th December 1857, 486. Mammalia, remains of extinct, in gravel, 50, 59. Mathematics, laws of operation and sy- stematization of, 85. Matteucci (C.) on the electric proper- ties of insulating or non-conducting bodies, 2. on the electrical phenomena which accompany muscular contraction, 344. , results of researches on the elec- tric function of the torpedo, 576, 644. Matthiessen (A.) on the alloys (Parti.), the specific gravity of alloys, 12, 207. on the electric conducting power of alloys, 205. on the effect of the presence of metals and metalloids upon the elec- tive conductivity of pure copper, 460. Maxwell (J. C.) on the theory of com- pound colours and the relations of the colours of the spectrum, 404. , postscript to a paper on compound colours, &c., 484. Membrana tympani, mode in which so- norous undulations are conducted from, to the labyrinth, 32. Mercury, conductivity of, 14. Merrifield (C. W.) on a new method of approximation applicable to elliptic and ultra-elliptic functions, 474. Metals, on the expansion of, 315. Methyl and methylene series, experi- ments in, 613. Mills (E. T.) on bromphenylamine and chlorphenylamine, 589, 644. Monamines, contributions towards the history of (No. III.), compound am- monias by inverse substitution, 594, 644. Muller (H.) on the resin of Ficiis rubi- ginosa, and a new homologue of ben- zylic alcohol, 298. Muscles, effects of freezing on the phy- siological properties of, 523. Muscular contraction, on the electrical phenomena of, 344. Muscular movements resulting from the action of a galvanic current upon nerve, inquiry into, 347. Nerves, distribution of, to the element- ary fibres of striped muscle, 519. Nervous system, lesions of, producing diabetes, 27. Nitrogen bases, 621. Nitrogen, new compounds produced by the substitution of, for hydrogen, 591. Nitrogen of vegetation, on the sources of; and whether plants assimilate free or uncombined nitrogen, 544. Nitrophenylenediamine, action of ni- trous acid on, 495. Non-conducting bodies, electric pro- perties of, 2. Numbers, problem on the divisibility of, 208. Ocean currents, on the producing forces of, 235. Ozone, on the volumetric relations of,427. Ozone-box, a new, 531. Parasites, vegetable, in hard animal structures, 95. Pavy (F. W.) on lesions of the nervous system producing diabetes, 27. on the alleged sugar-forming func- tion of the liver, 528. 656 INDEX. Pettigrew (J.) on the arrangement of the muscular fibres of the ventricu- lar portion of the heart of the mam- mal, 433. Phenylamine, new derivatives of, 104. Phospharsonium compounds, 608. Phosphate of lime, occurrence of, in a crystalline form in human urine, 281. Phosphorus bases, researches on : No. VI., 100 ; No. VII., 189 ; No. VIII., 603; No. IX., 608; No. X., 610; No. XI., 613 ; No. XII., relations be- tween the monoatomic and the poly- atomic bases, 619, 645. , contributions to the history of, Parts I., II., III., 568. Photochemical researches, Part IV., 39. Plagiostomes, on the structure of the chorda dorsalis of, and on the rela- tion of its proper sheath to the de- velopment of the vertebrae, 214. Pliicker (J.), abstract of a series of papers and notes concerning the elec- tric discharge through rarefied gases and vapours, 256. Polariscope, observations made with, during the ' Fox ' Arctic Expedition, 558. Pollock (SirF.) on Format's theorems of the polygonal numbers (first com- munication), 571. Poly-ammonias, notes of researches on : No. VI., 104 ; No. VII., 224 ; No. VIII., 495 ; No. IX., 596 ; No. X., 598. Polygonal numbers, on Fermat's theo- rems of (first communication), 571. Powell (B.) comparison of some recently determined refractive indices with theory, 199. Pratt (J. H.) on the curvature of the Indian arc, 197, 648. Prestwich (J.) on the occurrence of flint- implements, associated with the re- mains of extinct mammalia, hi un- disturbed beds of a late geological period, 50. Purple of the ancients, natural history of, 579. Quaternary cubics, on, 513. Radcliffe ( C. B .), an inquiry into the mus- cular movements resulting from the action of a galvanic current upon nerve, 347. Radiant heat, transmission of, through gaseous bodies, 37. Rankine (W. J. M.), supplement to a paper read January 27, 1859, on the thermodynamic theory of steam-en- gines with dry saturated steam, and its application to practice, 183. Refractive indices, comparison of with theory, 199. Regelation, note on, 440. , on the apparent universality of a principle analogous to, 450. Ringer (S.) on the alteration in the pitch of sound by conduction through dif- ferent media, 276. Ritter (K.), obituary notice of, xlii. Roscoe(H.E.) , photochemical researches, Part IV., 39. Royal Medal awarded to A. Cayley, 173 ; to Gr. Bentham, 176. Ryan (Sir Edward), election of, 289. Sabine (E.) on the solar-diurnal varia- tion of the magnetic declination at Pekin, 360. on the laws of the phenomena of the larger disturbances of the magnetic declination in the Kew Observatory, with notices of the progress of our knowledge regarding the magnetic storms, 624. Salmon (Rev. Gr.) on quaternary cubics, 513. Sensibility, experimental researches on, 510. Sheffield (Earl of), election of, 510. Sight, analysis of, 381. Simpson (M.) on the action of acids on glycol (second notice), 114. on cyanide of ethylene and succinic acid (preliminary notice), 574, 644. Smith (Lieut.-Col. 0. H), obituary no- tice of, xxiv. Spectrum, relations of the colours of, 404, 484. Spottiswoode (W.) on an extended form of the index symbol in the calculus of operations, 207. Solar spectrum, on the lines of, 339. Sound, alteration of pitch of, by con- duction through different media, 276. Stanley (Lord Edward), election of, 192. Staunton (Sir Gr. T.), obituary notice of, xxvi. Steam, density of, at all temperatures, 469. Steam-engines with dry saturated steam, application of thermodynamic theory of, to practice, 183. Stephenson (R.), obituary notice of, xxix. Stewart (B.), description of an instru- ment combining in one a maximum and minimum mercurial thermometer invented by Mr. James Hicks, 312. INDEX. 657 Stewart (B.) on the light radiated by heated bodies, 385. on the nature of the light emitted by heated tourmaline, 503. Storm of October 1859, notice of the, 561. Storms of Oct. and Nov. 1859, remarks on the, 222. Succinic acid, cyanide of, 574. Sulphamidobenzamine, on, 598. Sunlight, determination of chemical ac- tion of, 45. Superheated steam, law of expansion of, 469. Tate (T.), experimental researches to determine the density of steam at all temperatures, and to determine the law of expansion of superheated steam, 469. Temperature of bodies moving in air, 519. of flowers and leaves of plants, 534. Tendons, repair of, after subcutaneous division, 196. Thermometer, description of a new maximum and minimum mercurial, 312. Thomson (J.) on recent theories and ex- periments regarding ice at or near the melting-point, 152. Thomson (W.), analytical and syntheti- cal attempt to ascertain the cause of the differences of electric conductivity discovered in wires of nearly pure copper, 300. , measurement of the electrostatic force produced by a Daniell's battery, 319. , measurement of the electromotive force required to produce a spark in air between parallel metal plates at different distances, 326. on the thermal effects of fluids in motion, 502; temperature of bodies moving in air, 519. Torpedo, on the electric function of, 576. Toynbee (J.) on the mode in which sonorous undulations are conducted from the membrana tympani to the labyrinth in the human ear, 32. Triethylphosphine, on oxide of, 603. Triphosphonium compounds, 189. Tyndall (J.), note on the transmission of radiant heat through gaseous bodies, 37. Ureas and so-called ureas, some remarks on, 598. Urine, pathological importance of oc- currence of phosphate of lime in, 281. Ultra-elliptic functions, on a new me- thod of approximation applicable to, 475. Vacua, carbonic acid, luminous dis- charge of voltaic batteries in, 393. indicated by the mercurial siphon - gauge and the electrical discharge, 274. Vapour-densities, anomalous, 596. Victoria Regia, anatomy of, 14. Voltaic battery, electrical discharge in vacua with an extended series of, 36. Voltaic discharge in vacuo, interruption of, by magnetic force, 269. Walker (D.), observations made with the polariscope during the 'Fox' Arctic Expedition, 558. Waller (A.), experiments on some of the various circumstances influencing cu- taneous absorption, 122. Wanklyn (J. A.) on the synthesis of acetic acid, 4. Waters (A. T. H.) on the intimate struc- ture, and the distribution of the blood- vessels, of the human lung, 16. Weber (W. E.), Copley Medal awarded to, 172. Welsh (J.), obituary notice of, xxxiv. Williams (C. GK) on isoprene and caout- chine, 516. Wine, effects produced by, in blood- corpuscles, 186. Wrottesley (Lord) on the application of the calculus of probabilities to the results of measures of the position and distance of double stars, 133. END OF THE TENTH VOLUME. Printod by Taylor and Francis, Red Lion Court, Fleet Street. OBITUARY NOTICES OF DECEASED FELLOWS. DR. RICHARD BRIGHT was the third son of Mr. Richard Bright, an eminent merchant of Bristol, and commenced his education at a private school in the neighbourhood of that city. He subsequently was placed with the late Dr. Carpenter of Exeter. In the autumn of 1808, he matriculated at the University of Edinburgh, and attended the general lectures delivered at that celebrated school ; but it was not until the following year that he entered upon the studies more immediately connected with the medical profession. In the summer of 1810 he accepted an invitation to accompany Sir George Stuart Mackenzie and Mr. (now Sir Henry) Holland to Iceland ; and the departments of Botany and Natural History in * The Travels in Iceland,' subsequently published by Sir George Mackenzie, were written by Dr. Bright. On his return from Iceland he studied at Guy's Hospital for two years, and it was here that he acquired a taste for pathological investigations. He returned to Edinburgh in 1812, and graduated at that University in the following year. He intended likewise to take a degree at Cambridge, and entered as an undergraduate at Peterhouse; but he kept only two terms, finding the college requirements as to residence incompatible with his profes- sional pursuits. He then became a pupil, as he was subsequently a colleague, of Dr. Bateman at the Carey-street Dispensary, and ac- quired a knowledge of cutaneous diseases under that distinguished disciple of Willan. When the Continent was opened to travellers by the general peace of 1814, Dr. Bright visited Holland and Belgium, and spent some months at Berlin, where he attended the practice of Horn and of Hufeland, and made the acquaintance of Klaproth, Rudolphi, and Heim ; during his residence at the Prussian capital, he acquired a • thorough knowledge of the German language. From Berlin he went to Dresden for a short time, and arrived before the close of the year at Vienna, where he attended the practice of Hildebrand, Rust, and Beer, and became acquainted with Baron Jacquin, Prochaska, and the elder Frank. From Vienna he proceeded in the spring of 1815 to Hungary, and, on his way home, passed through Brussels about a fortnight after the battle of Waterloo, availing himself of the 11 occasion to witness the medical and surgical practice among the sick and wounded. His * Travels in Hungary/ published in the year 1818, had reference to this period, and were deservedly popular. His account of the gipsies in that country was especially interesting ; and his sketches, from which all the plates in that work are copied, showed his artistic skill to great advantage. In December 1816 he was admitted a Licentiate of the College of Physicians, and was soon after elected Assistant Physician to the London Fever Hospital. In the zealous discharge of his duties there, he contracted fever during a severe epidemic, and narrowly escaped with his life. In the autumn of 1818 he again set out on a visit to the Continent, and soon after his return to England, in 1820, commenced practice as a physician in London. From this time he concentrated the whole of his public duties on Guy's Hospital, of which he became Assistant Physician, holding that appointment until 1824, when he succeeded to the office of Physician. His devotion to the duties of his profession, and to pathology in particular, through- out the period of his connexion with Guy's Hospital, was most re- markable. During many years he spent at least six hours a day in that great practical school, and his indefatigable industry and un- rivalled talent for observation then laid the foundation for his well- known discoveries in renal disease. After giving lectures on medical botany, Dr. Bright, in 1824, began to lecture on the theory and practice of medicine, and after some years associated Dr. Addison with him in that duty. He also, in conjunction with that gentleman, projected a work intended as a class-book and entitled ' Elements of the Practice of Medicine.' Only one volume was published, which appeared in 1839, and is understood to have been chiefly the composition of his coadjutor. Di\ Bright resigned the post of Physician at Guy's Hospital in the year 1843, and on his retirement was complimented by the Governors with the honorary title of Consulting Physician. In 1832 he was elected a Fellow of the Royal College of Physi- cians, and in the following year delivered the Gulstonian Lec- tures, the subject being " The Functions of the Abdominal Viscera, with Observations on the Diagnostic Marks of the Diseases to which the Viscera are subject." In 1837 he delivered the Lumleian Lec- tures at the College, and he chose for his (subject the disorders of Ill the brain. He subsequently presented the College with a descriptive account of the pathological collection of Dr. Matthew Baillie. He became a Fellow of the Royal Society in 1821 ; and at a subsequent period received the Monthyon Medal from the Institute of France. Although Dr. Bright had occasionally suffered from illness for several years, the final and fatal attack — which was found to have depended on an extensive ossification of the aortic valves — was of short duration. He first became seriously ill on the 1 1th of Decem- ber, 1858, and on the 15th, at midnight, breathed his last. Dr. Bright's contributions to medical science are both numerous and important. His c Reports of Medical Cases,' contained in two royal quarto volumes, published in 1827 and 1831, embrace investi- gations on diseases of the kidney, the lungs, and the brain and nervous system, and on the pathology of fever. The plates of this great work are all coloured ; they were executed under the author's immediate superintendence, and are exquisite samples of the peculiar art of representing faithfully and without exaggeration the morbid appearance of tissues and organs. This celebrated work, rich as it is in the fruits of sagacious and untiring research, by no means comprehends the whole of Dr. Bright's published contributions to medical science. The volumes of the ' Medico-Chirurgical Transactions,' from the 14th to the 22nd inclusive (1828 — 1839), contain various papers from his pen; and to the ' Guy's Hospital Reports,' from their commencement in 1836 up to 1843, the date of Dr. Bright's retirement from the Hospital, he contributed no less than sixteen important memoirs. In the eighth volume there is a paper " On Patients with Albuminous Urine," the joint production of Drs. Bright, Barlow, and Rees, in the preface to which (written by Dr. Bright) he thus calls attention to an important innovation in clinical study : — " The few following pages will be found to contain the record of the first attempt which, as far as I know, has yet been made in this country to turn the ample resources of an hospital to the investigation of a particular disease, by bringing the patients labouring under it into one ward properly arranged for observation." Such were the numerous arid varied contributions to general knowledge and to medical science made by Dr. Bright. No phy- sician of the present day has, in our country, surpassed, perhaps IV none has equalled him, in the extent of his original researches in pathology ; and although his fame as a discoverer is founded chiefly on his researches into the pathology of renal disease in connexion with dropsy, his minute and unwearied investigation into the mor- bid anatomy of the kidney, and his detection of the albuminous state of the urine as pathognomonic of disease of that organ, yet a perusal of his writings abundantly convinces us that he brought the same sagacity and industry to bear upon many other problems in patho- logy and practical medicine. His labours in this country, as those of Andral and Louis in France, of Hufeland, the two Franks, and others in Germany, and Abercrombie in Edinburgh, contributed greatly to establish a more practical mode of investigation than had previously prevailed — a more direct attention to the connexion between the symptoms during life and the post-mortem appearances — a more constant and extensive application of animal chemistry and of the powers of the microscope to the elucidation of morbid conditions. Regardless of systems, a maxim laid down by him in early life, in the preface to his ( Travels in Hungary,' as applicable to the traveller, Seems to have guided him throughout his distinguished career : "correct observation," says he, "and faithful statement are the cardinal virtues on which his character must depend." WILLIAM JOHN BRODERIP, Esq., was the son of an eminent medical practitioner in the city of Bristol, where he was born on the 2 1st of November, 1789. Having received a sound training in classical knowledge at a provincial seminary, he proceeded in due time to Oxford, where he entered as a student at Oriel College. At Oxford he made the acquaintance of Dr. Buckland, who at that time (1809) was Fellow and Tutor of Corpus Christi College, but had as yet scarcely turned his mind to that study in which he afterwards became so distinguished. Young Broderip, on the other hand, carried with him to the University a considerable knowledge of Natural History, and especially of Conchology, with which he had from his earliest years been more or less familiar through means of a collection belonging to his father. Such as it was, the zoological acquirement of the student became of service to the future Professor, who in after-years of well-earned fame, was happy to acknowledge that he got his first practical lesson on fossil shells, and gathered what became the nucleus of his own fossil cabinet, in a walk to Shot- over Hill with his young friend Mr. Broderip. After taking his degree of B.A., Mr. Broderip became a diligent student of the law at the Inner Temple. He was called to the Bar in 1817, and in 1822 was appointed a police magistrate, in which office he continued till 185C. In the latter period of his career he was elected "Bencher" and "Treasurer" of Gray's Inn, and to him was confided the especial charge of the library of that Society. Amidst his arduous duties as a magistrate, Mr. Broderip found time to renew his zoological studies, and to begin the formation of a conchological cabinet, which soon grew into first-rate importance, and became an object of special interest to foreign naturalists visiting London, who seldom failed to profit by Mr. Broderip's readiness to open it freely to their inspection. This collection was purchased for the British Museum. Mr. Broderip was elected Fellow of the Linnean Society in 1824, of the Geological Society in 1825, and of the Royal Society in 1828. He was a zealous cooperator in the formation of the Zoological Society, of which he was one of the original Fellows and Members of Council. He was Secretary of the Geological Society, conjointly with Sir R. Murchison, till the year 1830. His death took place on the 27th of February, 1859, from an attack of serous apoplexy. These particulars of Mr. Broderip's personal history have been abridged from a brief memoir of him by one of his most distinguished friends*, who knew him well; and the following account of Mr. Broderip's scientific labours is borrowed entire from the same source. " To the * Transactions of the Geological Society J (2nd series, vol. v. p. 171), Mr. Broderip contributed a paper "On some Fossil Crustacea and Radiata found at Lyme Regis in Dorsetshire." His description of " The Jaw of a Fossil Mammiferous Animal found in the Stonesfield Slate " is published in the third volume of the 1 Zoological Journal.' To the same periodical Mr. Broderip com- municated " Observations upon the Volvox ylobator" " On the Manners of a live Toucan exhibited in this country," " On the Utility of preserving Facts relative to the Habits of Animals, with additions to two Memoirs in ' White's Natural History of Selborne,' " ' On the mode in which the Boa Constrictor takes its Prey," " On * Prof. Owen in the Obituary Notices of the Linnean Society, 1859. VI the Habits and Structure of Paguri and other Crustacea," a "Notice on the Mus messorius" together with several valuable conchological articles. The chief bulk of Mr. Broderip's original writings on Malacology was consigned to the ' Proceedings ' and * Transactions ' of the Zoological Society. I may refer to the Indexes of those col- lections and publications, and to the f Bibliographia Zoologise et Geologiae,' published by the Ray Society, for the titles of these numerous and valuable memoirs. " Few naturalists have more closely observed — none perhaps have more graphically and pleasingly described — the habits of animals. Mr. Broderip's ' Account of the Manners of a tame Beaver,' one of the pets that tenanted his chambers, published in the work en- titled ' The Gardens and Menagerie of the Zoological Society ' (vol. i. p. 167), affords a favourable example of his tact as an observer and power as a writer. Had circumstances permitted, he would have been a Field Naturalist second only to Gilbert White. When his friend Professor Owen became, through Royal favour, the tenant of one of the lodges in Richmond Park, Broderip would spend there much time in close observation of zoological phenomena afforded by the garden and the wooded vicinity of Sheen Gate. A note an- nouncing the commencement of nidification in the adjacent rookery, or the arrival of a migratory song-bird, would immediately bring the retired Police Magistrate to Richmond Park. Many references to facts so observed are made in those delightful combinations of pro- found and quaint learning with direct and close observation of nature which were contributed by Broderip to the ' New Monthly Maga- zine ' and to c Frazer's Magazine,' and which he afterwards collected and reprinted in the volumes entitled ' Zoological Recreations ' (8vo, 1847), and * Leaves from the Note-book of a Naturalist' (8vo, 1851). " Mr. Broderip was ever ready to aid a brother Naturalist. His col- lections, his rare zoological library, his pure classical taste and varied accomplishments, made the assistance he was able to give most valu- able. We find it freely acknowledged in the early editions of Sir C. Ly ell's ' Principles of Geology,' in the ' British Fishes ' of Yarrell, in the ' Silurian System ' of Murchison, and the * Bridgewater Treatise ' of Buckland. Broderip communicated a most valuable Table 01 the Situations and Depths at which recent Genera of vn Marine and Estuary Shells have been observed,' to the Appendix of De la Beche's ' Researches in Theoretical Geology/ and, in con- junction with Captain King, ' Descriptions of the Cirripedia, Con- chifera, and Mollusca collected during the Voyage of H.M.SS. Adventure and Beagle, 1826-30 ' (Zoological Journal). " To the ' Quarterly Review ' Mr. Broderip contributed articles on the Zoological Gardens, on the Vine, on the Cetacea and Whale- fisheries, on the Writings of Captain Basil Hall, on the Bridgewater Treatise of Dr. Buckland, &c. But the main bulk of this inde- fatigable student's zoological writings are contained in the ' Penny Cyclopedia/ viz. from AST to the end, including the whole of the articles relating to 'Mammals/ 'Birds/ 'Reptiles/ 'Crustacea/ 'Mollusca/ 'Conchifera/ 'Cirrigrada/ ' Pulmograda/ &c., 'Buffon/ 'Brisson/ &c., and 'Zoology.' " His last publication, ' On the Shark/ appeared in the March Number of ' Frazer's Magazine/ It was the ' first part' of an article on that subject, and bears all the marks of a mind in full intellectual vigour," ISAMBARD KINGDOM BRUNEL was the only son of the late Sir Marc Isambard Brunei, whose mechanical genius and originality of conception he largely inherited. Young Brunei was born at Ports- mouth in the year 1806, at the period when his father was engaged in the construction of the block-machinery for the Royal Dockyard. He received his general education chiefly at the College Henri Quatre at Caen, where at that time the mathematical masters were particu- larly celebrated ; and to his acquirements in that science may be attributed the early successes he achieved, as well as the confidence in his own resources which he displayed throughout his professional career. On his return to England, he was, for a time, practically engaged in mechanical engineering, at the Works of the late Mr. Bryan Don- kin, and at the age of about twenty he joined his father in the con- struction of the Thames Tunnel, and there- attained considerable experience in brickwork, the use of cements, and more especially in meeting and providing for the numerous casualties to which that work was exposed. The practical lessons there learned were in- valuable to him, and to his personal gallantry and presence of mind, Vlll on more than one occasion, when the river made irruptions into the tunnel, the salvation of the works was clue. One of his first great independent designs was that for the pro- posed suspension hridge across the river Avon, from Durdham Down, Clifton, to the Leigh "Woods ; and the acceptance of his proposal he owed to the fact that, upon the reference of the competing designs to two distinguished mathematicians, for the verification of the calcula- tions, his alone was pronounced to be mathematically exact. Want of funds alone prevented, at that period, the execution of the design, which, however, there are now some hopes of seeing carried into effect by transplanting to that site the present Hungerford Suspension Bridge, which is itself the work of Mr. Brunei. His introduction to Bristol led to his appointment as Engineer to the Docks of that city, which he materially improved. He had been previously engaged in the construction of the Old North Dock at Sunderland, and subsequently he designed the Bute Docks at Cardiff. In 1833-34 he was appointed Engineer to the Great Western Railway ; and whilst engaged on the surveys, he matured his views of the Broad Gauge, relative to which he sustained one of the hardest fought engineering contests on record. This work placed his reputa- tion high among Engineers, and henceforth his mental and physical powers were taxed almost beyond those of any other member of the profession. His attention to all the details of even the smallest works was unremitting ; and the Hanwell and Chippenham Viaducts, the Maidenhead, and other masonry bridges, the Box Tunnel, and the iron structures of the Chepstow and Tamar bridges on the extension of the Railway to the South and West, attest the boldness and originality of his conceptions, his taste in designing, and his skill in the use of various constructive materials. The partial failure at the opening of the Great Western Railway appeared only to incite his inventive faculties, and to afford a field for the exhibition of his great powers. All the physical impediments were met and conquered ; and his perseverance was ultimately crowned with success, in attaining a speed of travelling, combined with comfort and security, hitherto unrivalled. In the attempted adaptation of the atmospheric system of propul- sion to the South Devon Railway he was, however, signally unfortu- nate, in spite of all the ingenuity displayed ; but this failure had the IX effect of bringing into view a most pleasing feature of his character ; for while he duly paid up all the calls upon the stake he had in the undertaking, he at the same time refused to accept the professional emolument to which he was entitled. His services were in constant demand, in railway contests, before Committees of both Houses of Parliament ; and he was employed to construct the Tuscan portion of the Sardinian railways, as well as to advise upon the Victorian lines in Australia, and the Eastern of Bengal. Intimately, however, as the name of Isambard Brunei will ever be connected with the railway epoch in Great Britain, it is probably as the originator of the system of extension of the dimensions of steam- vessels that he will be best known to posterity. The * Great Western ' steam-ship was his first innovation on the usual system. In constructing that vessel, which was much larger than any previously built, he had the able assistance of Mr. Paterson, of Bristol, as the shipwright, and of Mr. Joshua Field as the constructor of the engines ; and in spite of adverse anticipations, even among practical men, the most triumphant success crowned his efforts, and demonstrated the correctness of his views. His attention was at that time directed to the subject of propul- sion by the screw, a subject on which Mr. F. P. Smith had been long and perseveringly labouring ; and the experiments made by Mr. Brunei, in his voyages on board the 'Archimedes/ convinced him of the practicability of the adaptation of the system to large vessels. He then designed the 'Great Britain/ an iron ship of dimensions far exceeding those of any vessel of its period : that the first essays were not entirely successful must be attributed to the fact of the machinery not having been designed by those whose peculiar study it had been to produce engines of the class required for such vessels. The disaster in Dundrum Bay demonstrated the scientific design and the practical strength of the hull of the ship, and the successful voyages since made have proved the correctness of his original views. He was then appointed the consulting Engineer of the Australian Steam Navigation Company, whom he advised to construct vessels of five thousand tons burthen, to run the entire voyage to Australia without stopping. His counsels were, however, not followed. The 'Great Eastern5 was his crowning effort; and to the design and execution of this gigantic vessel, far surpassing in dimensions any ship hitherto constructed, he devoted all his energies. The labour was, however, too great for his physical powers, and he broke down under the wearying task ; leaving to Mr. Scott Russell and Messrs. James Watt and Co., his cooperators in the construction of the hull and engines, the actual completion of the work he had so well and so perseveringly brought up to the day of starting on the trial trip. The disasters attending the launch and the trial trip were perhaps inseparable from so novel an experiment, on so gigantic a scale, but the ultimate results may be looked forward to with confidence. "Whatever they may be, the impulse given by Mr. Brunei to the construction of large-sized vessels is already felt both in our mercan- tile marine and in the Royal Navy. This sketch of the professional labours of Mr. Brunei is of neces- sity brief and incomplete, nor can the details be given of the nume- rous scientific investigations in which he was engaged ; but the devotion, during ten years of considerable portions of his time, to completing the experiments made by his father, to test the applica- tion of carbonic acid gas as a motive power in engines, must be mentioned. His special objects of study were mechanical problems connected with railway traction and steam navigation ; and although he was not, perhaps, so sound, or so practical a mechanic as his friend, and, at the same time, constant opponent, Robert Stephen- son, yet his intuitive skill and ready ingenuity enabled him to arrive at satisfactory solutions. The characteristic feature of his works was their size, and his besetting fault was a seeking for novelty, where the adoption of a well-known model would have sufficed. This defect has been unfairly magnified, wherever the pecuniary results of an undertaking have not reached the preconceived standard ; and due allowance has not been made for the difficulties encountered in the prosecution of a new and bold enterprise. It might, perhaps, have been as well if a uniform gauge had been originally established for the United Kingdom, — and such may still be the ultimate result ; but we must still admire the indomitable energy and consummate skill with which Mr. Brunei and his coadjutor, Mr. Saunders, pushed the broad gauge and its tributaries westward to Bristol, Gloucester, XI and through Wales, to Milford Haven, — then south-west to Exeter and Plymouth, and onwards to the Land's End ; and after invading the north-west manufacturing district of Birmingham, finally arriving at the shore of the Mersey opposite to Liverpool. This alone would have sufficed for the lifetime of many men ; and in truth the stupen- dous labours undertaken by Brunei could scarcely be performed without overtaxing the mental and physical faculties, and eventually causing them to break down. Mr. Brunei was fervently attached to scientific inquiry ; he was a good mathematician, and possessed great readiness in the practical application of formulae. He was elected at an unusually early age a Fellow of the Royal Society, and was an old Member of the Institution of Civil Engineers, of whose Council he was one of the Vice-Presi- dents ; he belonged to most of the principal Scientific Societies of the Metropolis, and several Foreign Societies, and was a Knight of the Legion of Honour. A liberal patron as well as a discriminating judge of art, he was himself devoted to artistic pursuits, and his early drawings, as well as his professional sketches, attest his feeling for purity of design. Of his private character, those only who were admitted to his inti- macy could judge correctly. Brunei was not a demonstrative man, but there was a fund of kindness and goodness within, which only required to be aroused to stand forth in high relief. It has been well said of him by an old friend, — " In youth a more joyous, kind- hearted companion never existed. As a man, always overworked, he was ever ready by advice, and not unfrequently, to a large extent, by his purse, to aid either professional or private friends. His habitual caution and reserve made many think him cold and worldly, but by those only who saw merely his exterior could such an opinion be entertained. His carelessness of contemporary public opinion, and his self-reliance, founded on his known character and his actual works, were carried to a fault. He was never known to court ap- plause. Bold and vigorous professionally, he was as modest and retiring in private life." He was cut off — in his fifty-fourth year — just when he had acquired that mature judgment which in such a profession as that of the Civil Engineer can be attained only by long experience, and when the greatest work of his life had reached the very eve of completion. xii EDWARD BURY, Esq., was born at Salford, near Manchester, on the 22nd of October, 1794. He received his early education at a school in Chester. From early youth he exhibited, in various ways, a taste for machinery and construction, and eventually he became established as a manufacturer of engines and machinery at Liver- pool. For some years following the opening of the Liverpool and Manchester, and the London and Birmingham Railways, Mr. Bury supplied numerous locomotive engines for those lines ; and he appears to have been very successful in practically applying in the construc- tion of these engines various improvements in steam-machinery which had been recently introduced or suggested. The details of his im- provements are described in a paper " On the Locomotive Engine," which he contributed to the ' Transactions of the Institute of Civil Engineers.' He also acquired much consideration on the Continent on account of his steam-machinery, and especially for his improved engines employed in the navigation of the Rhone. For some years after the opening of the London and Birmingham Railway, Mr. Bury had the entire management of the locomotive department ; and it deserves to be noticed, that, whilst his administrative services were duly recog- nized by the Directors, his tact, judgment, and conciliatory dis- position gained for him, in a most unusual degree, the regard and confidence of those employed under him. Mr. Bury afterwards undertook a similar charge on the Great Northern Railway some time after it opened ; and in the mean time he had been engaged in different important engineering works at home and abroad. He sub- sequently withdrew from active life, and died in his retirement, on the 25th of November, 1858. The date of his election into the Royal Society is February 1, 1844. HENRY HALLAM, Esq., was born at Windsor (A.D. 1777). His father was Canon of Windsor and Dean of Bristol ; the latter pre- ferment he resigned during his lifetime. Mr. Hallam was educated at Eton, and to Eton he felt, and evinced throughout life, strong and grateful attachment. Both his sons were likewise educated there. Classical learning, then almost the exclusive study in that school, found a congenial mind in Mr. Hallam, and to the last he took great delight in its cultivation. Already at Eton he had become a sound and accurate scholar. Some of his verses, printed in the Xlll 'Musse Etonenses,' are among the best in that collection, and show his command of pure and vigorous Latin, some fancy, and more thought than is usual in boyish compositions. From Eton he passed to Christ Church, Oxford. If his academic career was undi- stinguished, it was because in his time the University offered hardly any opportunities of distinction. But he remained a faithful mem- ber of the University. At the height of his fame he undertook the office of Examiner in Modern History ; and Christ Church did her- self credit by enrolling his name (he was already Doctor of Laws) among her honorary students created under the new academic system. Soon after he left the University, Mr. Hallam commenced the study of the Law. He entered himself as a member of the Inner Temple, became a Bencher, and took so much pleasure in the society of his legal friends, that, almost to the close of his life, he availed himself of the privileges and discharged the duties of that dignity. Some inde- pendent fortune, which was gradually increased, and an office under Government, in the Stamp Department, — an office which he held till the dissolution of the Board, — happily placed him above the necessity of striving for the emoluments of his profession, while those legal studies were an admirable preparation for his future career. Had he devoted himself to the practice of the Law, there can be no doubt that, although he may not have had the bold and ready eloquence, the pliancy, quickness, and versatility of a consum- mate advocate, yet his profound, accurate, and comprehensive learn- ing, his indefatigable industry, his sagacity in penetrating to the depths of an abstruse subject, his grave, calm wisdom, which had so much of the true judicial character, might have led him to the highest honours and rank in the Law. It is well, however, for his country, for the cause of letters, and indeed of Constitutional Law itself, that he left the dignity of the Bunch or of the Woolsack to his eminent contemporaries, and became — what no other man of his day could have become — the Historian of Constitutional Government and Law. In that character, and in that of a man of letters, he has acquired fame and influence as extensive as the world-wide English language, and indeed throughout the whole of Europe, where his works are generally known by translations. Mr. Hallam became, by deliberate choice and predilection, a man of letters in the highest and noblest sense. His dignified mind, and we may add, his indepen- xiv dent circumstances, as they had placed him above following the Law, so also raised him above following literature as a profession. He was in the enviable position that, while he sought and obtained the fame, he could disdain the drudgery of authorship ; and there was no fear that such a mind would degenerate into indolence, or indulge in the serene voluptuousness of literary leisure. He was a man of books, but not of books only ; he took great delight in society, in which he mingled freely ; and his own house was open not only to many attached friends, and to his legal contemporaries, but to states- men, men of letters, of art, and of science, and to cultivated foreigners, whom he received with easy hospitality. There were few distin- guished men in England, or even in Europe, who were not proud of his acquaintance ; with many he lived on terms of the most intimate friendship. Mr. Hallam became early a Member of the Royal Society. Though not strictly to be called a man of science, yet his active and com- prehensive mind was sufficiently grounded in the principles of most of the exact sciences, especially of mathematics, to follow out their progress with intelligent judgment, and to watch their rapid advance with the utmost interest. In the proceedings of this, and of other kindred societies, particularly the Antiquarian, as well as in the administration of the British Museum, of which he was an elected Trustee, he took part ; and always, from his remarkable range of knowledge and sound practical habits, with great advantage. But though Mr. Hallam had thus early taken up his position as a man of letters, he did not come forward as an author till of mature age, and then, with a publication which had demanded years of industrious research and of multifarious inquiry. It was the grave and deliberate work of a man conscious of great powers, one also (which is more rare) fully conscious of the responsibility attached to such powers, and who well knew that the best faculties and attain- ments may be wasted, as to permanent usefulness and enduring fame, by that hasty ambition which grasps too eagerly after popular applause, and wearies the public mind by incessant demands on its attention. Till this time Mr. Hallam was only known by his general reputation as a well-read and accomplished scholar, and by some articles in the ' Edinburgh Review.' The conductor of that journal, then at its height of power and fame (as appears from recent publi- XV cations), fully appreciated the value of his aid, the extent and the variety of his attainments ; one of his articles on Scott's 'Dryden* was remarkable as blending the courtesy due to a man like Walter Scott with free and independent judgment of his opinions, and at the same time as giving a just but discriminate criticism on the most unequal of our great poets. It was not till past his fortieth year (A.D. 1818) that Mr. Hallam announced himself to the world as an author ; but his t View of Europe during the Middle Ages ' placed him at once in the highest rank of historic writers. Of the great qualifications of a historian, except that of flowing, rapid, living narrative (precluded by the form of his work, which unavoidably took that of historical disqui- sition), none appeared to be wanting. There was profound research into original sources of knowledge, where they existed ; the judicious choice of secondary authorities, which always met with generous and grateful appreciation ; sagacity in tracing the course of events and the "motives of men ; thorough independence of judgment, which cared not what idols it threw down in the pursuit of truth ; singular firmness with unaffected candour ; above all, an honesty of purpose, which almost resembled a passion (the only passion which he betrayed); a style manly, clear, vigorous, — if inartificial, sometimes unharmo- nious, yet sound idiomatic English, — an apt vehicle for the English good sense which was the characteristic of the whole. There was no brilliant paradox, no ingenious theory to which all the facts must be warped: all was sober, solid, veracious. The 'View* was received not only with respect, and with the acclamation of all qualified to judge of such a work, but even with popularity, considering its subject and extent, surprising. It was emphatically described by a high authority of the day as a book which every scholar should read, and every statesman study. Like all great works of the kind, it created and supplied a want in the public mind. The History of the Middle Ages up to this time was a wilderness, which few were disposed or able to penetrate. There had been much laborious investigation, much ingenious speculation on parts of the subject ; but it was a labyrinth which wanted a clue, — darkness which repelled, confusion which bewildered. The ' View ' was as remarkable for its completeness and comprehensiveness as for its depth and accuracy. Though the subjects on which Mr, Hallam dwelt at greatest extent, XVI and it seemed with greatest predilection (as, indeed, of the most im- portance), were the rise, growth, and development of the governments, laws, civil, political and religious institutions of the European family of nations, yet the hook likewise entered with great though proportion- ate fulness on the progress of customs, inventions, language, letters, poetry, arts and sciences. It was enlivened hy many passages of fine criticism ; the note on Dante, for instance, may he read with high interest, after all that has been subsequently written on the great Italian poet. Since the publication of Mr. Hallam's work, awakened curiosity, the study of the philosophy of history, chiefly by Conti- nental writers, and, above all, religious zeal, have investigated almost every point relating to the Middle Ages with emulous ardour and industry ; yet Mr. Hallam's work has stood the test, and still maintains its ground. Mr. Hallam himself, with the modesty inseparable from true wisdom, and only anxious for the promulgation of sound truth, instead of narrow jealousy of trespassers upon his province, watched with careful interest every advance in knowledge on those subjects which he had treated almost without a guide. In a supplemental volume, afterwards incorporated with the original work, he collected from every quarter of Europe whatever in his judgment might throw a broader and clearer light on these dark places of mediaeval history. Nearly ten years elapsed before the publication of Mr. Hallam* s second great work, f The Constitutional History of England,' in July 1827. This was in some respects a continuation of part of the former book, which, among the other polities of Europe, had traced the growth and expansion of the British Constitution during the Middle Ages. It may be almost enough to say of this work, that by common consent it has become the standard authority on its all- important subject. It is constantly appealed to in the Houses of Parliament ; it is the text-book in the Universities as well as in the higher schools ; and this, from a general infelt acknowledgment of its truthfulness, which overawes and convinces against their will those to whom its doctrines may at first sight seem unacceptable. Nor was this from a cold, stately assumption of superiority to the great questions which have divided Englishmen in all ages. Through- out the work, in which every event which has stirred the passions of men, every character illustrious for good or for evil in our annals, passes in review, and is summoned to judgment, XV11 though Mr. Hallam holds avowedly and without disguise his own strong opinions, those of a calm, conscientious Whig of the old school, still there is an enforced impression that nothing could tempt him to be an unfair partisan ; that he seeks, and only seeks — and seeks with- out fear, without compromise, without awe of great names, without respect for popular idolatry — right and truth, justice and humanity, sound law, tolerant religion. If there has grown up a more general accordance of sentiment and opinion on English Constitutional History; if extreme differences have died away, and, so far as past times are concerned, the old party watchwords have nearly sunk into oblivion; if there has been greater general sympathy for the wise and good, more unanimous reprobation of the base and bad, this may in some degree be attributed to the influence of ' The Constitutional History of England/ After another interval of nearly the same length (in Sept. 1838 and July 1839) appeared the 'Introduction to the Literature of the 15th, 16th, and 17th Centuries/ This view of the intellectual deve- lopment of the world during the most active and prolific period in the history of the human mind, if with Mr. Hallam a work of labour (to most others it had been a work of intense labour), was yet a work of love. It was the overflow of a mind full to abundance of the best reading on almost all subjects, a disburthening, as it were, and a relief from the stores of knowledge accumulated during a long life. If it be hardly possible for a single mind to achieve a history of literature during three centuries (the work bore the modest title of ' Introduc- tion to the Literature of Europe '), yet much is gained by the unity of the work, by the proportion, harmony and order in the distribution of its parts ; and if one mind was capable of passing a fair judgment on such different productions of human thought and imagination, it was that of Mr. Hallam. How well he had read the best authors may be tested by his criticisms on Shakspeare, on Ariosto, on Cer- vantes, and on some of our older poets ; his power of grappling with more profound and abstruse subjects, by his estimate of Locke ; while writers of a more dry and uninviting class, scholars, even gramma- rians, pass before us, if with less minute investigation, with much more than a dull and barren recension of their names* Only one other work, a small one, bears the name of Mr. Hallam ; and that, though printed for private distribution, having been liberally b XVI11 communicated to his numerous friends, may justify at least a passing allusion. It records a melancholy chapter in an otherwise uneventful life to which men of letters might have looked with respectful envy. It pleased Divine Providence to try this wise and blameless man with almost unexampled domestic affliction. He married an excellent lady, the daughter of Sir Abraham Elton. Of many children, four only, two sons and two daughters, grew up to mature age. The eldest son was one whom such a father (for Mr. Hallam, with not much outward show, was a man of the deepest and most tender aifections) could look upon with pride, with love, and with hope allotted to few distinguished men. What was the promise of Arthur Hallam may be known from the volume of his ' Remains/ printed by his father ; what he was in disposition as well as in mind, from the exquisite 'In Memoriam' of Mr. Tennyson. The blow which bereft Mr. Hallam of this son was frightfully sudden. His eldest daughter and his wife followed the first-born to the grave. One son remained ; he too, if of less originally speculative and poetic temperament than the elder, with great acquirements and endowments, was gifted also with a gentleness and tenderness of disposition, singularly fitted to be the consolation, the surviving hope of such a father. He too was carried off with almost equal suddenness. One daughter remains, married to Colonel Farnaby Cator, and has children. Bowed but not broken by these sorrows, Mr. Hallam preserved his vigorous faculties to the last, and closed his long and honoured life in calm Christian peace. ARTHUR HENFREY was born at Aberdeen, of English parents, on the 1st of November, 1819. He studied medicine at St. Bartho- lomew's Hospital, and in 1843 became a Member of the College of Surgeons, but delicate health prevented him from engaging in the practice of his profession. Accordingly, having a taste for botany, and having already attained to great proficiency in that science, he thenceforth devoted himself exclusively to its pursuit* and soon acquired a distinguished position among English Botanists. In 1847 he was appointed Lecturer on Botany at St. George's Hospital, and in J854 succeeded the late Professor Edward Forbes in the Botanical Chair at King's College ; he was also Examiner in Natural History to the Royal Military Academy and the Society of Arts. XIX Notwithstanding his feeble bodily constitution, Professor Henfrey's labours were incessant. Whilst constantly engaged in original in- vestigations, the results of which he made known in various papers which appeared in the * Transactions ' of the Royal and Linnean Societies, the t Annals and Magazine of Natural History,' and the 'Journal of the Agricultural Society/ his untiring industry also enabled him to furnish numerous translations and abstracts of foreign memoirs to the Natural History Journals, and to give reviews and critical notices of botanical works in these periodicals, as well as in the 'Quarterly Review.5 Moreover, he translated several independent works from the French and German languages, and composed some valuable elementary treatises on botanical sub- jects, of which his 'Elementary Course of Botany/ published in 1857, is the last and most important. For three years also he con- ducted the 'Journal of the Photographic Society/ and since 1858 was one of the most active editors of the new series of the ' Annals of Natural History/ Professor Henfrey was a man of an amiable and gentle nature, which neither the pressure of daily toil nor the trying interruption of ill-health could ever ruffle : his death, on the 7th of September, 1859, at the early age of thirty-nine, hastened as it probably was by his unremitting exertions, has been deeply lamented by all who knew him. THOMAS HORSFIELD, M.D., was born at Bethlehem, in Penn- sylvania, on the 12th of May, 1773, of parents who were Moravians, in which Christian communion he lived and died. He was educated for the medical profession in the University of Pennsylvania, where he took the degree of Doctor of Medicine in 1798. Early in life he went to Java, where he passed sixteen years, actively engaged in the pursuit of Natural History, to which he had devoted himself. During his residence in Java, he thoroughly explored every part of the island, in quest of its natural productions. From Java he visited Banca, and gave the fullest and best account which exists of that island. After the restoration of Java to the Dutch in 1816, Dr. Horsfield made a long sojourn in Sumatra, and there continued his favourite studies ; but having made the friendship of Sir Stamford Raffles, who is said to have imbibed from Horsfield his well-known XX love of Natural History, he followed that eminent person to England in 1818, and soon after was made Keeper of the Museum of the East India Company, which charge he held till his death, which took place on the 24th of July, 1859, in the 87th year of his age. Whilst in the East, Dr. Horsfield diligently collected the plants of Java and the adjacent islands ; and the folio volume afterwards published in this country, under the title of « Plantse Javanicee Ra- riores,' contains figures of selected species from his collections, with descriptions furnished by his friends Mr. J. J. Bennett and the late Mr. Robert Brown. During his stay in Java also, he contributed various papers on the Geology and Natural History of the Eastern Islands to the * Transactions of the Batavian Society,' of which he was a member. The same collection also contains a very interesting experimental inquiry, by Dr. Horsfield, on the physiological action of the Upas Antiar poison, the juice of a tree which was afterwards figured and described in the ' Plantse Javanicse.' His writings on Zoology are, chiefly, his 'Zoological Researches in Java,' 4to, 1821 ; the valuable Catalogues of the several zoological departments of the East India Company's Museum, and numerous papers on zoological subjects contributed to the ' Linnean Transactions,' the ' Zoological Journal,' and the ' Proceedings of the Zoological Society.' His latest publication is the c Catalogue of the Lepidopterous Insects in the East India Museum,' of which only the first volume has appeared ; it was compiled by Mr. Moore, his assistant, from Dr. Horsfield's materials and manuscripts, and under his direction. Dr. Horsfield had some years before commenced a Catalogue of these insects, of which only two parts were published (1828-29); and this publication, though incomplete, deserves notice, as containing an elaborate Introduction, with a general arrangement of the Lepidoptera founded on their metamorphoses. The importance of the transformations of insects in reference to their classification had indeed become early impressed on Dr. Horsfield's mind, and he accordingly spent three seasons during his stay in Java in collecting the larvae of numerous species of Lepi- doptera, watching their development, and making careful descrip- tions and drawings of their successive changes up to the perfect state. Dr. Horsfield was a member of various learned societies at home and abroad. He was elected a Fellow of the Linnean Society in XXI 1820, and of the Royal Society in 1828. He was a man of retired habits, but of amiable character and unblemished integrity. MANUEL JOHN JOHNSON, the late RadclifFe Observer, expired suddenly on the 28th of February, 1859, in the fifty-fourth year of his age. Cut off as he was in the midst of his invaluable labours and in the full vigour of his high intellectual powers, his death has caused a severe loss to science, which, however deeply deplored by the numerous friends who enjoyed the privilege of his intimate acquaint- ance, will only be appreciated in its full extent when the great and important works which he designed, and so nearly executed, shall have been duly completed. After passing through the usual course of studies at Addiscombe College, Mr. Johnson commenced his public career in 1821 as an officer in the St. Helena Artillery, and while acting as aide-de-camp to General Walker, then in command of the island, was appointed to the control of a small but efficient observatory, founded by the Honourable East India Company. The establishment came into active service in 1829, and in the short space of three years and a half, a valuable catalogue of 606 stars had been observed by the young astronomer and a single assistant. This catalogue was afterwards published, at the expense of the Court of Directors, in the * Memoirs of the Royal Astronomical Society/ and obtained for its author the award of the gold medal of that body in the year 1835. On the termination of this important work, Lieut. Johnson re- turned to England, and entered the University of Oxford as an undergraduate. On the death of Professor Rigaud, in 1839, he was appointed Radcliffe Observer, and speedily rendered the Observatory one of the most active scientific institutions in the world. One of his first acts was to obtain permission of the Radcliffe Trustees to publish an annual volume of Observations — thus scorning the life of comparative ease he might have chosen, and giving the world an effectual guarantee for the performance of those self-imposed duties to which he so willingly and faithfully devoted the remainder of his life. He accordingly immediately began the re-observation of * Groombridge's Circumpolar Catalogue/ adding thereto all conspi- cuous adjacent stars, and many others of especial interest. To this important work the resources of the Observatory were devoted for XXII more than fourteen years : volume after volume has been issued with a regularity hitherto unsurpassed ; while the high character for accu- racy of the star-places in each annual catalogue has been fixed by the unanimous approval of the most eminent European authorities. To render this great work complete, however, required the reduction of every individual observation to a fixed epoch, and the incorporation of the whole into one general catalogue. Much yet remained to be done, though the work was fast progressing ; and had its lamented author been spared another year or two, he would have presented to astro- nomers a monument of industry and devotion to duty unsurpassed in the annals of British science. The point now most to be desired, previous to the publication of the final catalogue, is, a rigorous investigation of the errors of division of the Meridian Circle, which has not yet been attempted, owing to the too numerous and pressing pursuits of the unwearied and enterprising Director. In 1854 a new project was commenced,— 'A Catalogue of Remark- able Objects,' comprising all stars of suspected large proper motion, the binary systems, variable and coloured stars, all bright stars down to the third magnitude, and indeed whatever of interest was obser- vable with a four-inch object-glass. In the discussion of proper motion Mr. Johnson's plan of procedure was that adopted by Madler, viz., instead of deducing the change of place from two most widely distant authorities alone, to employ all published positions, and thus to deduce the best possible final value ; leaving no broken link, no contradictory observation uncorrected, or at least unnoticed, to raise future discussion as to the value derived. Such a method is of course the most laborious, but nothing less can be regarded as definitive, and, to secure the best results, neither time nor trouble was spared. The most eventful epoch in the history of the Radcliffe Obser- vatory and of its late Director remains to be noticed, viz. the establish- ment of the fine heliometer — a treasure unique in its improvements, unrivalled in its marvellous powers, but almost the labour of a life to develope and turn to the best account. It was erected by its makers, Messrs. Repsold of Hamburg, in October 1849, and was forthwith employed in incessant and toilsome research by its skilful manipulator. The Radcliffe Trustees, with their usual liberality, not only provided and equipped this very costly instrument, but, in order XXlll to enable Mr. Johnson to devote himself almost exclusively to its use without interrupting the pursuits of which we have already spoken, granted him an additional assistant. After a careful study of the peculiarities of the instrument, in the course of which his acquaint- ance with German enabled him to derive most important aid from the learned disquisitions of Bessel, Hansen, Wichman, and other astronomers, an elaborate description of it appeared in the preface to vol. xi. of the Radcliffe Observations. The detection and treatment of certain corrections peculiar to the Oxford heliometer afforded a fine example of Mr. Johnson's suggestive genius. Before com- mencing the more difficult investigations of stellar parallaxes, he passed, step by step, through a patient and judicious course of training, by the measurement of some well-known double stars, of the diameters of the planets, and of the brighter stars in the Pleiades. In 1851 the heliometer was employed in a novel and purely original manner to determine the light-ratios used by different astronomers in their estimations of the magnitudes of the fixed stars. In the two following years his most successful achievements with this instrur ment were accomplished, viz. the determinations of the parallaxes of the stars 61 Cygni and 1830 Groombridge. His near agreement with the values obtained by Bessel for the former, and by Professor Peters and Otto Struve for the latter object, was most satisfactory, and gave ample evidence of his complete success in these intricate investigations. In 1854 and 1855 the parallaxes of Castor, Arc- turus, a Lyree, and one of the comparison stars previously used in the case of 1830 Groombridge, became the objects of researches the details of which are given in vol. xvi. of the Radcliffe Observa- tions. The same spirit of enterprise and progress which Mr. Johnson evinced in the purely astronomical part of his duties was manifested in a yet more marked degree in his management of the meteorolo- gical department, From a single page of ordinary records of the barometer and thermometer, the subject rapidly expanded, under his treatment, to an extent hitherto unprecedented. The introduction of photography as a means of barometric registration by Mr. Ronalds, and its ingenious extension to the wet- and dry-bulb thermometers by Mr. Crookes, as also, at a later period, to the records of the direc- tion and strength of the wind and the depth and time of fall of rain, XXIV added such an amount of anxious labour to the already overwhelming requirements of his office, as for the last three years completely pre- cluded him from making further researches with the heliometer. This is the more to be deplored, as there is reason to fear that the monotonous, though cheerfully endured, fatigue inevitable in reducing so novel and accumulative a process to a regular system, accelerated the sad event which it has been our mournful task to record. An earnest labourer himself, Mr. Johnson was ever ready to further the scientific labours of those whom he had it in his power to assist ; and it was in this spirit that he sanctioned and encouraged his assistant, Mr. Pogson, in making independent researches with the Radcliffe Equatorial, after the hour of closure of the official work of the Observatory, whereby that gentleman was enabled to discover four planets and ten new variable stars. The remembrance of his high social qualities, his refined taste, and extensive fund of ready information in literature and the fine arts as well as in science, his frank and agreeable demeanour, his thorough integrity of purpose, and his unostentatious benevolence, will be long cherished by a wide circle of friends, especially in the University, where he was so bright an ornament and so general a favourite. He was President of the Royal Astronomical Society in the years 1857 and 1858, and was elected a Fellow of the Royal Society in 1856. Lieutenant-Colonel CHARLES HAMILTON SMITH was born in Austrian Flanders, on the 26th of December, 1 776, of a Protestant family holding a good position in the province, and partly of British descent. He was bred to the military profession, and began his career as a volunteer in the British army in the Netherlands, but soon obtained a commission, and in 1797 was transferred to a regi- ment in the West Indies. After serving for twelve years in that part of the world, he returned to Europe, and joined the Walchereri expedition as Deputy Quartermaster- General. In 1813 he was again employed in the Low Countries ; and on this occasion he succeeded, with a handful of men, in capturing the fortress of Tholen, whereby a new and better basis of operations was opened up to the British forces in Brabant. After being engaged, in 1816, on a mission to the XXV United States and Canada, in connexion with the Foreign Office, he, in 1820, retired from active public duty. In the course of his active military life, Colonel Smith found time for varied study. History, Archaeology, and Zoology were his favourite subjects, and these he continued to cultivate in his retirement. The matured, results of his labours he gave to the world in various well- known works, of which he was sole or part author. For many of these he had early begun to accumulate materials, especially pictorial representations of the objects described ; and for this employment his taste and skill as a draughtsman gave him both inducement and facility. Whilst on the staif of the Horse Guards, he wrote the military part of Archdeacon Coxe's c Life of Marlborough,' which is said to have excited the interest of Napoleon at St. Helena as to its author- ship, inasmuch as it showed a practical acquaintance with military affairs scarcely to be expected of a churchman. He is also the author of the article " War " in the ' Supplement to the Encyclopedia Bri- tannica,' and of the introductory paper on the " Science of War " in the ' Aide Memoire J of the Royal Engineers. The first publication in which the powers of Colonel Smith's pencil were called into requisition was the ' Costume of the original Inhabitants of the British Islands,' undertaken in connexion with the late Sir Samuel Meyrick. A still greater work, which was in reality hardly less indebted to Colonel Smith, although his name does not appear in the title, is Sir S. Meyrick's ' Critical Inquiry into the His- tory of Ancient Armour.' We are informed that most of the illus- trations (blazoned in gold and colours) of that celebrated work were copied, with his full concurrence, from Colonel Smith's drawings. Well, however, as Colonel Smith was known as a historical anti- quary of no common order, his reputation as a writer on Natural History was perhaps higher. The article "Ruminantia" in Griffith's edition of Cuvier's 'Regne Animal' (1835) was written by him ; and many of the engravings in that edition were from his drawings. At a later period he supplied the volumes on « Dogs,' ' Horses,' and ' Introduction to Mammalia,' to Sir William Jardine's 'Naturalist's Library' ; and in connexion with the same series, he published in 1848 his * Natural History of the Human Species.' He was also the author of the elaborate articles on Natural History, and XXVI Warfare, in the ' Cyclopaedia of Scriptural Knowledge,' edited by Dr. Kitto. The extraordinary amount of materials collected by Colonel Smith is not, however, to be estimated only by his published works. He has left more than twenty volumes of manuscript notes on the most varied subjects. In many instances these notes illustrate his remarkable collection of drawings, amounting in number to many thousands. The whole of these valuable collections, as well as his personal assistance, were throughout his life placed freely at the dis- • posal of all to whom they could be of service ; and it was at all times sufficient for the Colonel to be assured that by his advice and assist- ance he could further the objects of the literary inquirer or the artist to ensure his active cooperation. Colonel Smith became a Fellow of the Royal Society in 1824, and of the Linnean in 1826. On the formation of the Devon and Corn- wall Natural History Society, he was elected President. On his retirement from active military service he fixed his residence at Ply- mouth, where he died on the 21st of September, 1859. Sir GEORGE THOMAS STAUNTON, Bart., D.C.L., was the only child of the late Sir George Leonard Staunton, who is well known to the public as having accompanied Lord Macartney as Secretary of the first Embassy to China, in the year 1 792, and as the author of the account of the Embassy which was afterwards published. He is not less known to those who are acquainted with the history of British India, as having, when Lord Macartney was Governor of Madras, concluded the peace with Tippoo Sultan in the year 1784. Sir George Thomas Staunton was born in May 1781, and died, after a succession of paralytic seizures, in the summer of 1859. He succeeded his father in the baronetcy in the year 1801. After his father's death he was the last male representative of a very ancient English family, the branch of it from which he was descended having been established as landed proprietors in the county of Gal- way in Ireland since the middle of the 1 7th century. Sir George Leonard Staunton had some peculiar notions as to education, which he endeavoured to carry out in the training of his son. The son was brought up entirely at home, under his father's eye ; and, except on a few very rare occasions, never associated with XXV11 boys of his own age, but lived entirely in the society of older persons. A tutor living in the house instructed him in the Greek and Latin languages. He had masters to teach him Mathematics, Botany, and other sciences, and he attended lectures on the various departments of Natural Philosophy. Partly, perhaps, from his not being occupied with the pursuits of other boys, but principally from his being natu- rally endowed with great powers of application and much readiness of apprehension, he made a remarkable progress in all these branches of knowledge ; so that when he was not more than fifteen or sixteen years of age he was as much advanced as many even diligent students when they are eight or ten years older. In the year 1792 he accompanied his father to China, under the nominal designation of Page to the Ambassador. For some time before the embassy embarked, and during the voyage to China, he had the opportunity of studying the Chinese language under two native Chinese missionaries from the Propaganda College at Naples ; and he soon made such proficiency as*to be able to speak it with tolerable fluency, and to copy papers written in the Chinese charac- ter. In this manner he became very useful to the embassy. When the embassy was presented at the Chinese Court, the Emperor in- quired for the little boy who could speak Chinese, conversed with him for some time, and good-naturedly presented him with an em- broidered yellow silk purse for holding areka-nuts, from his own girdle. On leaving China, Sir George L. Staunton engaged a Chinese servant to accompany him to England, in order that his son, by constantly communicating with him in Chinese, might keep up and extend his knowledge of the language. In the year 1799, having received the appointment of Writer in the factory of the East India Company at Canton, young Staunton proceeded a second time to China. He remained at Canton, with some occasional visits to Europe, until the year 1817, having for some time before his final return to England filled the office of Chief of the factory. His residence in China afforded him the opportunity of still further advancing himself in a knowledge of the Chinese language by means of native teachers. He was the first among the members of the factory who had ever studied the lan- guage of the country in which their duties required them to reside ; XXV111 and thus he became very useful by supers'eding the necessity of em- ploying native interpreters, in whom (principally from the fear which they had of the local authorities) much confidence could not be placed. While residing in China, he made several translations from the Chinese ; the principal, and that a work of great importance, being the ' Ta Tsingleu-lee,' or Chinese penal code. This last was published in the year 1810. Other translations of much interest, though of inferior importance to this, have been published since. In the year 1816 a second embassy was sent to China, the late Lord Amherst, Sir Henry Ellis, and Sir George Staunton being ap- pointed joint Commissioners of Embassy. An account of the pro- ceedings of this Embassy has been published by Sir Henry Ellis. Sir George Staunton, however, printed his private journal, and dis- tributed copies of it among his friends. After his return to England, Sir George Staunton purchased a house and landed property in Hampshire, where he afterwards re- sided during a part of every* year. For some time he had the honour of representing South Hants in Parliament. He afterwards repre- sented Portsmouth, and continued to do so until he resigned the charge a very few years before he died. After his being finally re-established in England, he occupied him- self but little with the pursuits of his early life ; though it may have been partly his knowledge of botany that led him to lay out an ex- tensive garden, with numerous hothouses and conservatories, full of the rarest trees and plants. Although his life was prolonged until he had entered on his 79th year, he was always of a delicate frame, and not capable of great physical exertion. Others observed in him a certain shyness and awkwardness of manner, of which his peculiar education affords an adequate explanation. But with this he on various occasions dis- played great moral courage and determination. Many instances of this might be quoted, but one will be sufficient. On the occasion of the second embassy, the Chinese Court refused to receive it unless the ambassadors performed the ceremony of the Kotou before the Emperor. Lord Amherst and Sir H. Ellis wished that they should do so, but Sir George was so satisfied that it would be regarded by the Chinese as an act of humiliation, and something like the homage paid to a feudal lord, that he positively refused his consent. The XxiX Chinese were aware of this, and threatened to dismiss the rest of the embassy, but to detain him as a prisoner. But he declared that this made no alteration in his view of the subject ; that, being con- vinced that he was right, he was quite ready to take his chance of whatever might befall him, rather than swerve from what he re- garded as the strict line of his duty. Mr. ROBERT STEPHENSON, M.P., the only son of the late Mr. George Stephenson, was born on the 16th of October, 1803, at "Wellington Quay, near Newcastle-upon-Tyne, where his father had charge of the colliery engine. The rudiments of his education were received at the village school at Long Benton, whence he was transferred, at the age of ten years, to the academy of Mr. John Bruce, at Newcastle, which he left at the age of sixteen. He then received some instruction in mathematics from Mr. Riddell, now the Master of the Naval School at Greenwich, and was apprenticed as a coalviewer to Mr. Nicholas Wood, with whom he stayed about three years. Mr. George Stephenson having by that time raised himself to the position of a consulting mechanical engineer, and appreciating the advantages of that education which it had not been his own good fortune to receive, determined to send his son to the Uni- versity of Edinburgh, where Robert Stephenson was entered in 1821. During one session, which was all that could be afforded for him, he followed so indefatigably the lectures of the celebrated Professors Leslie, Hope, and Jameson, that he carried off most of the prizes of the year ; and feeling the value of the opportunity, he laboured most assiduously, not only to learn everything that was placed before him, but more especially to lay the foundation for future self-instruction. In 1822 he quitted the university to become the apprentice of his father, at the works then first established at Newcastle-on-Tyne for the manufacture of machinery, and whence proceeded the loco- motive engines which were destined to produce such a revolution in the internal communication of all countries, His health having suffered from unremitting study and close appli- cation to his duties at the factory, he accepted in 1824 an appoint- ment to investigate and to report upon some silver mines in South America. This occupied him for nearly four years ; and upon his report the Columbian Mining Association was formed. Before his XXX departure for America he had assisted his father in the survey of the line of the Stockton and Darlington Railway, which was opened for traffic on the 27th of September, 1825. During the progress of the works, public attention was so much attracted to the subject, that the project was resuscitated for a railway between Liverpool and Manchester, intended chiefly for the conveyance of cotton from the port to the place of manufacture. Mr. George Stephenson was appointed to survey the line contemplated for the undertaking ; and being afterwards appointed engineer for the construction of the work, in the year 1826, and feeling the need of his son's assistance, he summoned him to England. Robert Stephenson, on his return home by way of the United States of America and through Canada, fell in with Trevithick, who was also coming home from South America. That steam locomotion should form a constant topic of conversation between two such men was only natural ; and Robert Stephenson, who was already acquainted with and had assisted in carrying out the improvements of his father in the Killingworth and other loco- motive engines, was well inclined to listen to what were then con- sidered the "visionary schemes" of Trevithick, whose utmost ideas of attainable speed were, however, so soon to be far exceeded. Whilst engaged, after his arrival in England, in assisting his father in the construction of the Liverpool and Manchester Railway, Robert Stephenson at the same time directed his attention to the systems of railway traction, and was successful in the competition for the prize offered by the Directors of the railway for the best locomotive engine. The result of his experiments, added to the joint Essay by himself and Mr. Joseph Locke, in replyto the Report of Messrs. "Walker and Rastrick, which recommended fixed engines and rope traction, led to the settled adoption of the locomotive engine, and contributed materially to decide the question of the general introduction of rail- ways in this country. Soon after this he constructed the ' Planet J engine, at the Newcastle factory, which became the type of all the very successful engines that have been since employed. About the same period the United States Government sent three officers of the corps of Topographical Engineers to examine into and report upon steam locomotion on railways as practised in this country. For these gentlemen Robert Stephenson designed and constructed two locomotive engines, embodying a special contrivance adapting them to traverse XXXI the sharp curves of the American railways ; and in the majority of the American engines that mode of construction has since been fol- lowed. Thus it is to Robert Stephenson that are due the types of the locomotive engines used in both hemispheres. The successful result of the Liverpool and Manchester Railway led to the project of a line between London and Birmingham. The survey for this line had been entrusted to Robert Stephenson, who removed to London for the purpose of devoting himself to the execu- tion of the works, which had also been committed to him. They were very heavy, and demanded the exercise of the greatest skill and constant personal attention, especially in such works as the Kilsby Tunnel, where the quantity of water met with threatened to stop the proceedings. The railway, which was commenced in 1834, was com- pleted in 1838 ; and such was the reputation acquired by the engineer, that his advice and assistance were henceforth sought in all the im- portant undertakings of the period, either for the construction of the works or in prosecution of the bills before Parliament. Foreign governments also sought his assistance ; and for the attention devoted to the scheme for the Belgian railways, both George and Robert Ste- phenson received from the King of the Belgians, in 1844, the deco- ration of the Order of Leopold. Robert Stephenson received also, in 1848, the Grand Cross of St. Olaf of Norway for similar services. He was thus consulted on the construction of railways in Belgium, Switzerland, Germany, Norway, Denmark, Tuscany, Canada, Egypt, the East Indies, and other countries. During the progress of these large systems of lines, he was called upon to design and to execute many very important and some very novel works, of which we can here only mention the Kilsby and numerous other tunnels, large viaducts, such as the High Level Bridge at Newcastle-on-Tyne, the Victoria Bridge at Berwick, and the Conway and Britannia tubular iron Bridges. The latter great innovation in constructive art, which has since been extended to architectural construction with the greatest success, was at first viewed with great distrust ; and it required some considerable time to convince the public of the security of such works : subsequently it was as difficult to settle the question as to the real originator of the system. We have here only to record that in 1855 the Council of Presidents and Vice-Presidents of the French Exposition, awarded to Mr. Robert Stephenson the Great xxxn Gold Medal of Honour for the invention and introduction of tlie system of tubular plate-iron bridges, and First Class Silver Medals to Messrs. William Fairbairn and Eaton Hodgkinson, for tbeir co- operation in the experiments ; and also to Mr. Edwin Clark, for his aid in the consideration of the designs and in the construction of the bridge itself. As a further recognition, the Emperor added the decoration of the Legion of Honour. This system of construc- tion has since been extended to the Victoria Bridge across the St. Lawrence River, in Canada, the total length of which is nearly two miles, in twenty-five spans. That bridge is the greatest example of the system, which has, however, also been employed on a large scale by Mr. Robert Stephenson, in the bridges across the Nile, at Benah and at Kaffre Azzayat, on the Egyptian Railway from Alex- andria to Suez. The limits of this memoir will only permit the further mention of the remarkable constructions on the sea- shore between Conway and Bangor, for the protection of the Chester and Holyhead Railway ; and the recent restoration of the iron bridge at Sunderland, which was the last engineering work upon which he was actively engaged. Mr. Robert Stephenson was considered as the leader in the cele- brated discussion, called the "battle of the gauges," for determining whether the narrow or the broad gauge should be the standard for the Kingdom. Events have since proved how correct were his views; and notwithstanding the brilliant talents of his friend, but then oppo- nent, the late Mr. Brunei, the broad gauge did not spread beyond a certain district. It was, moreover, to his strenuous and persistent opposition that was due the rejection of the atmospheric system of traction, attempted to be introduced on the Dalkey, the Croydon, and the South Devon Railways. For some years after he reduced the sphere of his active profes- sional employment, he was engaged in several important public in- vestigations, such as that of the Consulting Commission of the Metropolitan Sewers, and others. He made able investigations and reports upon various great undertakings, of which the Liverpool Water-works may be mentioned as an example ; and he wrote the article " Iron Bridges" in the < Encyclopaedia Metropolitana.5 The work of his predilection was, however, the management of the Engine Factory at Newcastle-on-Tyne. To that he devoted him- XXX111 self as a labour of love, thinking over improvements and designing innovations, the necessity for which had become apparent in the working of his lines of railway. In the year 1847, Mr. Robert Stephenson was elected to represent Whitby in Parliament, and he continued to sit for that borough until his decease. He did not speak much in the House ; but when he spoke he always commanded attention, and on such questions as that of the Canal of the Isthmus of Suez, which he is well known to have strenuously opposed, he carried every one with him. He was a very useful member of Committees ; and had his life been spared, there is no doubt that his services would have been even more frequently re- quired by the Government, who had already learned to appreciate the honesty and truthfulness of his views. He was devotedly attached to scientific investigations, and, as far as his occupations permitted, he was a frequent attendant at the various learned societies of which he was a member. He was elected a Fellow of the Royal Society in 1849, and served on the Council. He joined the Institution of Civil Engineers in the year 1830, was a member of Council, and filled the office of President from 1856 to 1858. IJe was also a Member of the Geological, Geographical, Astronomical, and Meteorological Societies, and of the Institute of Mechanical Engineers, as well as of numerous societies in the coun- try. The honorary degree of D.C.L. was conferred upon him by the University of Oxford in 1857; and he had previously received a similar honour from the University of Durham. A most successful professional career, unceasing activity and in- dustry, combined with wisely considered investments, resulted in producing a very large fortune, which he employed during his life- time most liberally, and from which at his decease, after providing munificently for his numerous relatives, and recollecting all his friends and dependents, he bequeathed upwards of .=£25,000 to a few chari- table institutions and scientific societies, — and this after having given such sums as 363000 at a time to the Literary and Philosophical So- ciety of Newcastle, to relieve it from debt, and to extend its sphere of utility, especially to young men of the working class— an advantage, by which Stephenson himself had profited in early life, and which he had never forgotten. The health of Mr. Stephenson had not been good for the last two XXXIV years ; and just before his last journey to Norway, he had complained of want of strength. Whilst in Norway he was very unwell, and ex- hibited such symptoms of decided liver complaint as induced his speedy return. During the voyage, heavy weather was experienced in the North Sea, and he was very sick and ill. Qn his arrival at Lowestoft, he was so weak as to be carried from his yacht to the rail- way, and from thence to his bed, at his residence in Gloucester Square, where his state grew so rapidly worse as to leave but faint hopes of his recovery. The affection of the liver was deeper than had been at first suspected, and was associated with further internal disease ; and although his state was for a time alleviated, there was not sufficient strength to struggle against the malady, which termi- nated his valuable life on the 12th of October, 1859. Thorough uprightness of character was in Mr. Stephenson joined with an amiable disposition, and he conciliated the affectionate regard of all with whom he came into immediate relation. To those who stood in need of his bounty his hand was ever open, but his bene- ficence was without display, and he rejoiced in an occasion of doing good unseen. His great care was for the children of old friends who had been kind to him in early life ; and many young hearts, who owe their present position to his kind solicitude and generosity, will mourn his irreparable loss. Mr. JOHN WELSH, Superintendent of the Kew Observatory, was born at Boreland, in the Stewartry of Kirkcudbright, on the 27th of September, 1824. His father was George, the eighth son of John Welsh, Esq., of Craigenputtock, a small estate in that district, which had been in the family from an early period. Mr. George Welsh, who was extensively engaged in agriculture, died in 1835, and his widow with his two sons settled at Castle Douglas, where the elder — the subject of this notice — continued his preparatory edu- cation, and the younger died in 1841, in his 13th year. In November 1839, Mr. John Welsh entered the University of Edinburgh, and studied Mathematics and Natural Philosophy, under Professors Kelland and Forbes, with a view to the profession of a Civil Engineer. He attained the highest prize but one of his year, also prizes in Classics ; he also studied Geology in the lecture- room and in the field, under the late Professor Jameson. XXXV In December 1842, Sir Thomas Brisbane, Bart., President of the Royal Society of Edinburgh, with the advice of Professor J. D. Forbes, engaged Mr. Welsh as an observer for his Magnetical and Meteorological Observatory at Makerstoun, under Mr. John Allan Broun, F.R.S., the Director, who, in his Report for 1845, says, — " I owe my best thanks to my principal assistant, Mr. John Welsh, for the care and assiduity with which he assisted me on all occa- sions, whether connected with the making or reducing of the ob- servations The more difficult observations for the magnetic dip, and all the determinations of constants, were made by Mr. Welsh and myself." In 1850, the period originally contemplated by Sir Thomas Bris- bane for the duration of the Observatory being completed, Mr. Welsh was anxious to obtain some other scientific appointment. To aid him in the attainment of this object, Sir Thomas gave him a letter of introduction to Colonel Sykes, F.R.S., at that time Chairman of the Kew Committee of the British Association ; Mr. Broun also wrote to Colonel Sykes, expressing his high opinion of Mr. Welsh's scientific ability ; and accordingly, at the Edinburgh Meeting of the British Association in 1850, the Kew Committee reported that they had engaged Mr. Welsh to assist Mr. Ronalds, F.R.S., who had, ever since the establishment of the Observatory, gratuitously under- taken the office of Superintendent. From this period to within a short time of his death, Mr. Welsh devoted himself to scientific labour in that establishment, upholding and, year by year, increasing the efficiency of a physical Observatory, which, without any pecu- niary aid from Government, has, since its commencement, been entirely supported by annual grants from the British Association, assisted from time to time by donations from the Royal Society. In 1851, shortly after his appointment to the Kew Observatory, Mr. Welsh presented to the Association an elaborate Report on the performance of Mr.Ronalds's three Magnetographs ; and at the same meeting (Ipswich) he described a Sliding Rule for Hygrometrical Calculations, and one for converting the observed readings of the Horizontal- and Vertical-force Magnetometers into variations of mag- netic dip and total force ; both sliding rules being devised by himself. In the same year, the Committee, being impressed with the im- portance of enabling scientific observers at home and abroad to c.2 XXXVI obtain, at a moderate cost, barometers and thermometers of more accurate construction and trustworthy character than those usually sold, directed Mr. "Welsh to undertake a series of experiments for that object. The results of his labours were most satisfactory, and are fully described in a paper printed in the Reports of the Asso- ciation for 1853. Accordingly, at the present time, standard instru- ments are supplied to scientific investigators direct from the Obser- vatory, and barometers and thermometers which have been compared with the standards at Kew, and each accompanied with its special table of corrections, are not only supplied to the Government De- partments of the Admiralty and the Board of Trade, but can now be obtained from any instrument-maker at greatly reduced prices. In the summer of 1852 Mr. Welsh made four ascents in a balloon, for scientific objects. A detailed account of these ascents and of the experiments he performed, with a description of the various instru- ments employed, and a statement of the general results obtained, was communicated to the Royal Society in 1853, and published in the ' Philosophical Transactions ' for that year. Sir John Herschel, in his article " Meteorology" in the 8th edi- tion of the ' Encyclopeedia Britannica,' makes the following remarks on Mr. Welsh's performance: — "All the observations were con- ducted with scrupulous precision, and the reductions very scienti- fically made ; . . . these four ascents leaving nothing to desire in point of instrumental appliances and scientific precision in their use." In 1854, Mr. Welsh, at the request of the Kew Committee, under- took a series of experimental investigations on the action of the mercury in marine barometers, known under the term of " pump- ing." For this purpose, he went, in company with Mr. Adie, to Leith and" back in a steamer, and subsequently to the Channel Islands. The result of his observations led him to the conclusion that the tube of a marine barometer should, in order to reduce the pumpings, be contracted, so that the mercury will take about twenty minutes to fall from the top of the tube to the height indicating the true pressure ; and that by this means the probable error from the cause indicated would not exceed 0*01 of an inch. The account of these experiments was published in the Kew Report for 1853. In 1855, in consequence of its having been represented to the Committee that Her Majesty's Government were anxious that mag- XXXV11 netical and meteorological instruments, showing the advanced state of those sciences in this country, should be sent to the Paris Exhi- bition, Mr. Welsh was requested to proceed to Paris with the instru- ments and to superintend the arrangements. An account of the instruments appears in the Report of 1855 of the Kew Committee. In the ' Philosophical Transactions' for 1856 there is a paper of Mr. Welsh's entitled " Mi Account of the Construction of a Standard Barometer, and Description of the Apparatus and Processes em- ployed in the Verification of Barometers at the Kew Observatory ;" and in the * Proceedings of the Royal Society/ vol. vi., a Report of the general process adopted in graduating and comparing the Standard Meteorological Instruments for the Kew Observatory ; also a Report of the graduation of Thermometers supplied from the Observatory for the use of the Arctic Searching Expedition under Sir Edward Belcher. In January 1856, a series of monthly determinations of the abso- lute magnetical force, and of the magnetic dip, was commenced at the Observatory by Mr. Welsh, with instruments provided by General Sabine from his department at Woolwich ; and in the same year a set of self-recording magnetometers were constructed : these were arranged in the basement of the Observatory, and have been in action since January 1858. In the Report of the British Association for 1856, Mr. Welsh described a process for the graduation of boiling- point thermometers intended for the measurement of heights. In 1857 Mr. Welsh was elected a Fellow of the Royal Society— a position, to which his qualifications fully entitled him to aspire, but which his natural diffidence would have led him to postpone, had it not been urged on him by those who appreciated his merits. To his personal friends he always spoke with feelings of gratitude of the mode in which his services to science had been thus recognized. Twenty years having elapsed since the execution of the Magnetic Survey of the British Islands, it was determined by the British Association that another survey should be made. With this view, a Committee, consisting of the same five members by whom the former survey was conducted, with the addition of Mr. Welsh, was appointed, and Mr. Welsh undertook the Magnetic Survey of the North British division of the United Kingdom. In the summer of 1857 he deter- mined the magnetic elements at thirty-one stations, and in the summer XXXV111 of last year he resumed his labours, completing the survey at twenty - four other stations in Scotland and the adjacent islands. Through the winter of 1857-58, Mr. Welsh had suffered from an affection of the lungs ; and on his return from Scotland, in the autumn of 1858, the disease had evidently made rapid progress. Arrangements had been made which would have enabled him to pass the winter in a tropical climate ; but acting under the best medical advice that could be procured in the metropolis, he, accompanied by his mother, proceeded to Falmouth. In that place, by the kindness of Mr. R. W. Fox and his family, Mr. Welsh received every attention which they had it in their power to offer. His only regret during his illness appears to have been his inability to complete the works he had undertaken. He died on the 1 1th of May, 1859, in the 35th year of his age, not less esteemed for his private worth by those who had the pleasure of his acquaintance, than appreciated for his emi- nent abilities and valuable services by men of science, PETER GUSTAV LEJEUNE DIRICHLET was born at Diiren, where his father was Commissaire de Poste, on the 13th of February, 1805. After going through the course of instruction followed in the Gym- nasium of Cologne, he went to Paris to continue his studies, and in May 1823 he became tutor in the family of General Foy. Here he formed an acquaintance with the most distinguished mathema- ticians of France. On the recommendation of Fourier, who was the first to appreciate his genius, and aided by Gauss, Von Humboldt procured for him an appointment in Prussia. In November 1827 he obtained the position of Teacher in the University of Breslau, and in the year following was nominated Professor Extraordinary'. Being appointed soon after to lecture at the Royal Military School of Berlin, he became Professor Extraordinary in the University of that place. On the 13th of February, 1832, he was elected a Member of the Royal Academy of Sciences of Berlin ; on the (fth of May, 1833, Corresponding Member of the Institute of France; in 1833 Corre- sponding Member of the St. Petersburg Academy ; in 1839 Ordinary Professor of the University of Berlin; in 1846 Member of the Gottingen Academy of Sciences. In 1847 a Professorship in the University of Heidelberg was offered to him. In 1854 he was elected Member of the Academies of Stockholm and Munich, and Foreign XXXIX Associate of the French Academy ; and in 1855 Member of the Bel- gian Academy, and Foreign Member of the Royal Society. After the death of Gauss he was appointed Professor of the Higher Mathematics in the University of Gottingen, in the spring of 1855, and entered upon the duties of his office in the autumn of the same year. He returned in bad health from an excursion in Switz- erland in the autumn of 1858, and died at Gottingen on the 5th of May, 1859. By his death the University of Gottingen has lost not only a di- stinguished teacher and a man of the brightest intellect, but per- haps the only mathematician of the time likely to succeed in com- pleting the unfinished works of Gauss, a task which he had declared himself willing to undertake. His mathematical memoirs, the first of which was presented to the Institute of France in 1825, are too numerous to admit of introducing their titles into this notice. They are published in the * Transactions ' of the Berlin Academy from the year 1833 to 1854, in 'Crelle's Journal' from 1828 to 1857, in the 'Monatsberichte' of the Academy for 1852-1855, and in volumes iv., v., ix., xii. of ' Liouyille's Journal.' THE BARON FRIEDRICH HEINRICH ALEXANDER VON HUM- BOLDT, was the second son of Alexander George von Humboldt, descended from a noble Pomeranian family. His father was a major in the Prussian army, and had served with distinction as aide-de-camp to the Duke Ferdinand of Brunswick in the seven years' war. The distinguished subject of our present brief notice was born at Berlin on the 1 4th of September, 1769. At the age of ten years he lost his father. From 1787 to 1789 he studied, first for some months in the Univer- sity of Frankfort on the Oder, and afterwards in that of Gottingen. During the vacations, he made geological excursions to the Harz, and on the banks of the Rhine, and published the results of his observations under the title ' Ueber die Basalte am Rhein, nebst Untersuchungen uber Syenit und Basanit der Alten.' In the spring of 1790 he made a hasty excursion through Holland, England, and France, in the company of George Forster, who sailed with Cook in his second voyage round the world. On his return from this excur- sion, he passed some months at Hamburg, preparing himself for a post in the Finance department of his native country. In June 1791 xl he went to Freiberg, where he attended the lectures of Werner, and became acquainted with Von Buch and Del Rio. During his residence at Freiberg he collected the materials for his work entitled ' Specimen Florae subterraneee Fribergensis et aphorisimi ex physiologia chemica plantarum.' After obtaining an appointment in the Administration of Mines at Berlin, he filled the office of Director- General of the mines of Ansbach and Baireuth from 1792 to 1797. During this time he prepared his work on the irritability of muscular and nervous fibre. On the death of his mother in 1796, his desire to travel increased. He resigned the post of Director of Mines, and devoted himself to the study of practical astronomy under v. Zach. After passing some months at Jena and Vienna, he made an attempt to visit Italy, accompanied by v. Buch, for the purpose of examining the volcanos of that country. Being forced by the war of which Italy was the scene to relinquish this undertaking, he passed the winter of 1 797-1798 in the study of meteorology at Salzburg and at Berchtesgaden. He was invited by Lord Bristol to accompany an exploring party into Upper Egypt, and went to Paris to procure the necessary instruments. On his arrival, in May 1798, he was apprised of the failure of Lord Bristol's project in consequence of the departure of the French expedition for Egypt. Here he became acquainted with his future fellow-traveller Bonpland. He obtained permission from the Directory to accompany Baudin in his voyage round the world. The sailing of this expedition having been postponed, he made an attempt to join the French in Egypt. Failing, however, in consequence of the non-arrival of a Swedish frigate in which he had been promised a passage to Tunis, he went to Spain, accompanied by Bonpland, where he passed the winter of 1 798-1 799. Encouraged by the Spanish Minister, Luis de Urquijo, to visit Spanish America, he and Bonpland embarked at Corunna on the 5th of June, 1799. They landed at Santa Cruz on the 1 9th of June, ascended the Peak and explored the Island of Teneriffe. On the 1 6th of July they reached the Cumana. After having traversed Venezuela, the valleys of the Orinoco and Amazon, the countries of Peru and Mexico, Ilumboldt embarked on the 7th of March, 1804, for the Havana, where he remained six months. After visiting the United States, he sailed from America on the 9th of June, and landed at Bordeaux on the 3rd of August, 1804. xli He made Paris his residence from 1805 till 1827, occupying him- self with the publication of the results of his travels, in eight separate works, and with various chemical and physical researches. He visited Naples with Gay-Lussac and v. Buch in 1805. During the residence of Prince William of Prussia in Paris in 1807-1808, Humboldt held a diplomatic appointment. In 1814 he accompanied his elder brother Wilhelm v. Humboldt, then sent on an embassy to London, and was elected a Foreign Member of the Royal Society in 1815. His ' Memoire sur les lignes isothermes ' appeared in 1817. He was present at the Congress of Aix-la-Chapelle in 1818, and at that of Verona in 1822, and in the same year accompanied the late King of Prussia to Naples. From the year 1827 he made Berlin his home. In 1829 he travelled with Ehrenberg and G. Rose, under the auspices of the Emperor Nicholas, through Siberia, as far as the frontiers of China. The results of this journey, which lasted nine months, are pub- lished in his * Asie Centrale,'and in G. Rose's ' Reise nach dem Ural, Altai, und dem Caspischen Meere.* After the French Revolution of 1830, v. Humboldt was commis- sioned by Frederick William III. to recognize the accession of Louis Philippe on the part of Prussia. About this time he completed his 'Examen critique de la Geographic du nouveau Continent.' In 1 84 1 he accompanied King Frederick William IV. to England, and visited Paris for the last time in the winter of 1847-1848. In 1845 he published the first volume of ' Cosmos,' a work which may be regarded as a development upon an extended scale of his * Ansichten der Natur,' the third edition of which appeared in 1849. The first part of the fourth volume of ' Cosmos ' appeared early in 1858 ; the second part is so far prepared that no obstacles to its completion are anticipated. He enjoyed good health till near the end of his life. In October 1858, he was attacked by an illness from which he never com- pletely recovered. On the 21st of April, 1859, in consequence of a cold, he was unable to leave his bed. He retained the use of his faculties till the morning of the 6th of May, when he became speech- less, and died at half-past two in the afternoon of the same day. In 1852 the Royal Society awarded him the Copley Medal for his eminent services in Terrestrial Physics, and he considered this to be d xlii the highest honour he had ever received. A letter from Dr. Pertz» the Librarian of the Royal Library at Berlin, to Sir Charles Lyell, states, that the Medal was found after his death amongst the objects which he wished to be for ever preserved in the family archives at Tegel. The outer envelope of the box containing the medal bore this inscription in his own handwriting : " Die wichtige beruhmte Cop- leysche Preis-Medaille der koniglichen Societat (in meiner Familie aufzubewahren in Tegel). Al. Humboldt. Sept. 1858." On the exterior envelope he had written : " Das ehrenvollste, das ich besitze, die beruhmte Copleysche Ehren-Medaille der koniglichen Societat zu London von 1852 in familien Archiv zu Tegel aufzubewahren. Al. Humboldt. 6 Marz, 1859." Looking for ward to the probable appearance of a complete biography of this illustrious philosopher and traveller at no very distant period, it is needless at the present time to enter more fully into the details of his life and labours. KARL RITTER was born at Quedlinburg on the 7th of August, 1779. His education was completed in the University of Halle. In 1798 he became tutor in the family of M. Bethmanu Hollweg, and travelled with his pupils through a large portion of Europe. He then went to Gottingen, in order to avail himself of the library of that place in prosecuting his researches in ancient history. After four years' assiduous labour, he succeeded Schlosser as Professor of History at Frankfort ; he was then chosen Professor of Geography in the Military School, and afterwards Professor of History in the University of Berlin. He was a Knight of the Order Pour le Merite ; Member of the Academy of Sciences of Berlin ; Foreign Associate of the French Institute ; Foreign Member of the Academies of Sciences of Gottin- gen, Copenhagen, St. Petersburg, and Munich ; Honorary Member of the Vienna Academy of Sciences, and of numerous other literary and scientific societies. He was elected a Foreign Member of the Royal Society in 1848. He died on the 28th of September, 1859. The most ^mportant of Ritter's works is the second edition of the * Allgemeine vergleichende Geographie,' the first volume of which appeared in 1822, and the twenty-third in 1859, accompanied by an Atlas, on which Etzel, Grimm, Mahlmann and Kiepert have xliii laboured in succession, This work, though still incomplete (of the three parts the author intended to devote to Asia Minor, only two, parts xviii. and xix. have been published), is considered the most valu- able work on Geography in existence. Among the other writings of Hitter, the following deserve especially to be mentioned : — ' Europa eingeographisch-statistischesGemalde' (1807); Vorhalle Europais- cher Volkergebilde vor Herodot ' (1820); 'die Stupas' (1838); 'die Colonisirung von New-SeelandJ (1842); 'Blick auf das Nilquell-land J (1844) ; ' der Jordan, und die Beschiffung des Todten Meeres' (1850); 'Blick auf Palestina' (1852); 'das Kameel' (1852). Many memoirs by Hitter have appeared in the 'Trans- actions ' of the Berlin Academy, and in the ' Journal of Universal Geography.' Some of these have been collected and published under the title of ' Einleitung zu einer mehr wissenschaftlichen Behandlung der Erdkunde.' These labours entitle M. Hitter to be considered as the creator of scientific geography. Instead of limiting geography to collecting isolated facts, and descriptions without logical order, he tried to discover the natural and intimate relations which exist between a country and its inhabitants : employing all the ideas which history and the natural sciences supply, he has drawn conclusions, which have erected the geography of the present time into a kind of physiology of the earth. Q Royal Society of London 41 Proceedings L718 v.10 Physical & Applied Sci Serials PLEASE DO NOT REMOVE CARDS OR SLIPS FROM THIS POCKET UNIVERSITY OF TORONTO LIBRARY