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From what has now been said it will be seen that Dr. Sharpey did not enter upon any active sphere of exertion, either as an investi- gator or as a teacher, till he had attained his twenty-eighth year; but with characteristic caution he was, during a number of years, preparing himself with the greatest diligence and care, by literary and scientific study, as well as by continental travel, for the duties of his after life. As a scientific investigator he was characterised by scrupulous care and accuracy in all his observations, and by an extensive and intimate acquaintance with what was previously known on the subjects. Thus it happens that thongh, as already remarked, he cannot be regarded as a copious observer or extensive discoverer of new facts, yet all the observations he has recorded may be ranked as important contributions to science at the time when they were made, and the greater number of them have retained their value to the present day, notwithstanding that the subjects to which they belong may, from the advance of knowledge, have considerably changed their aspect. As a systematic author there is everywhere apparent in his writings the same scrupulous accuracy and full knowledge of his subject, com- bined with a simplicity and clearness of statement, an appropriate choice of language, and a critical acumen, which have given them a high and lasting value. We have, it is true, to regret the fastidious- ness which deterred him from more copious publication, but we may console ourselves with the reflection that all he did publish bears the stamp of excellence, and that in abstaining from more extended literary productions he was ever spending his time and energies in the instruc- tion of his pupils and the advancement of the business of the scientific institutions with which he was connected. Dr. Sharpey’s usefulness and influence were probably more con- spicuous in his labours as a public teacher than in any other capacity. During the forty-three years in which he was constantly occupied in giving lectures on Anatomy-and Physiology, he devoted himself with ardour and perseverance to perfecting the information which he had to communicate to his pupils, and to extending and improving the means of illustrating his lectures, so that he was uniformly listened to with the closest attention and regarded as the highest authority on the subjects which he taught. Thus too, it happened that he was very frequently consulted by former pupils as well as by others with regard to the preparation and publication of memoirs or more exten- sive works which they had in contemplation, and it is easy to under- stand the advantages which accrued to those who appreciated and followed his advice, or the opposite effect which sometimes occurred from its being disregarded. X1x But the effect of Dr. Sharpey’s teaching upon a large number of pupils did not proceed alone from the superiority of the information conveyed, or the implicit reliance which his pupils placed in the fulness, accuracy, and truthfulness of the statements of their teacher, but it was also due to, and greatly enhanced by, the feeling of friendly attachment, and even of filial affection amounting to reverence, which was inspired in the minds of the pupils by his uniform kindness, justice, and candour. In the other public offices held by Dr. Sharpey during the greater part of the time of his residence in London, the superior qualities of his mind had equal scope in conducing to the efficiency and usefulness of his services. As an examiner in the University of London and afterwards as a member of the Senate, as Secretary of the Royal Society, as Member of the General Medical Council, as one of the Science Commissioners and a trustee of the Hunterian Museum, his extensive knowledge, unbiassed judgment, and strict impartiality, while they gave weight to his opinions and suggestions, aided largely in the promotion of measures favourable to the interests of science and the public good. Of the more private features of Dr. Sharpey’s life and character it is difficult for those who have been most intimate with him to express _ their estimate in sufficiently moderate terms. While he was universally admired for the extent and accuracy of his acquirements and respected for the soundness of his judgment, he was not less esteemed and beloved for the gentleness of his disposition, the kindness of his heart, and the geniality of his nature. His powers of memory,. naturally good, were carefully cultivated by the systematic turn of his mind and strengthened by exercise. His friends remember with delight the readiness with which, in the course of conversation, he could call up a desiderated quotation, or supply a fact on some doubtful point in history, philosophy, or science, or tell humorously some anec- dote which was equally apposite and amusing. He had not a single enemy, and he numbered among his friends all those who ever had the advantage of being in his society. JOHN STENHOUSE, the son of William Stenhouse and Elizabeth Currie, his wife, was born at Glasgow, 2lst October, 1809, and educated first at the Grammar School, and subsequently at Glasgow University, where he studied from 1824 to 1828. His tastes in early life were more literary than scientific, but owing to weak eyesight he was obliged to give up literature as a pursuit, and devoted himself to Chemistry, which he studied under Professor Graham and Dr. Thomas Thomson. His training in this science was first acquired at the Andersonian University, now Anderson’s College, Glasgow, and it was probably on this account he always took such a C xX lively interest in this Institution: during his lifetime he used all his interest to obtain bursaries and otherwise promote the study of his favourite science, and by his will he left a legacy to found a Scholar- ship in connexion with the Chemical Chairs in that College. He attended the Chemical lectures at Glasgow University in 1837, 1838, and 1839, and shortly afterwards left Glasgow for Giessen, where he continued his chemical researches under Liebig, and became acquainted with many of his fellow pupils, whose names have since become illustrious as workers in this portion of the field of science. It is apparently shortly before this time that his first paper, entitled “Darstellung und Analyse des Hippursaiures Althers,” was published in the ‘ Annalen der Chemie und Pharmacie,” vol. xxxi, p. 148 (1839). He was with Liebig, at Giessen, about two years, and then returned to Glasgow, where he remained until the failure of the Glasgow Commercial Hxchange deprived him of the fortune be- queathed him by his father, which had hitherto rendered him inde- pendent. Stenhouse received his degree of LL.D. in May, 1850, and it was about this time that he was an unsuccessful candidate for the Professor- ship at Owens College. He left Glasgow for London in January, 1851, and in the following month was appointed Lecturer on Chemistry to the Medical School at St. Bartholomew’s Hospital, but was obliged to resign the appointment in 1857 owing to a severe attack of paralysis. He then went to Italy, and resided there with his mother until her death, which took place at Nice in February, 1860. He returned to England in June of the same year, and again commenced scientific research with that indomitable energy which was so characteristic of him, and which enabled him to overcome the obstacles occasioned by his bodily infirmities. In 1865 he succeeded Dr. Hofmann as one of the non-resident Assayers to the Royal Mint, but was deprived of the appointment when the office was abolished in 1870. In November, 1871, a Royal Medal of the Royal Society was awarded to him for his long-continued chemical researches, which have proved of great value in the arts and manufactures. During the last four years of his life he suffered greatly from rheu- matism in the eyelids, which compelled him to live almost constantly in a darkened room, and at times caused him the greatest pain. It was not, however, until within a few weeks of his death that he became sensibly feebler; he ultimately sank into a sleep, and died a painless death from old age and decay of nature in the early morning of the 31st December, 1880, in the seventy-second year of his age. He was buried on the 6th of January in the High Church New Cemetery in Glasgow, on the north side of the Cathedral. Dr. Stenhouse was one of the few surviving founders of the Chemical XX1 Society, a Fellow of the Institute of Chemistry, an honorary member of the Berlin Chemical Society, as also of the Philosophical Society of Manchester, and the Pharmaceutical Society of Great Britain. It will be evident from an inspection of the titles of the numerous papers (more than 100 in number) published by Dr. Stenhouse during the past forty years, in the Transactions and Proceedings of the Royal Society, the “‘ Journal of the Chemical Society,” ‘‘ Liebig’s Annalen,” and other scientific journals (either alone or in conjunction with Mr. C. E. Groves), that these for the most part relate to what may truly be called ‘‘ Organic Chemistry,” the chemistry of com- pounds found in organised bodies, so that his name will long be asso- ciated with numerous carbon compounds obtained from plants, and derivatives formed from them. Among all these he applied himself chiefly to the principles from the lichens, and made known the results in eighteen papers. One of his communications, published in 1880, is worth mention as it relates to ‘“ Betorcinol,” a substance he had discovered some thirty-two years previously. It is but seldom that a chemist lives to complete a work begun so long before. Although the eminence he attained in organic research is fully recognised, his contributions to our technical knowledge are not so generally known. He was the author of many ingenious and useful inventions in dyeing, waterproofing, sugar manufacture, and tanning ; but the greatest and most permanent benefit has been conferred by his application of the powerful absorbent properties of wood charcoal to disinfecting and deodorising purposes, which took the form of charcoal air-filters and charcoal respirators. Of Dr. Stenbouse’s personal character, those who knew him inti- mately could never speak too highly, his general conversation and fund of anecdote rendering him a most pleasant companion. His in- genuity and quick perception were remarkable, and this combined with his unflagging industry, and patience and resignation in great bodily suffering, enabled him to continue his scientifi¢é work with unabated vigour, even after the effects of paralysis prevented him from _per- forming experiments with his own hands. Houmesrey Luoyp was born in Dublin on the 16th of April, 1800. His father was the Rev. Bartholomew Lloyd, afterwards Provost of Trinity College, Dublin, at that time a Junior Fellow. Having re- ceived his early education at Mr. White’s school in Dublin, he entered Trinity College on July 3, 1815, obtaining at the Entrance Hxamina- tion, which was at that time altogether classical, first place among sixty-three competitors. He obtained Scholarship (Classical) in 1818. At the examination for the degree of B.A. he obtained the Science Gold Medal, the highest honour which could be gained by an under- graduate. In the year 1824 he obtained a Fellowship, given then, as a XX1l now, to the best answerer at a special examination. He was elected, in 1831, to the chair of Natural and Experimental Philosophy, which he filled with distinguished ability till 1843, when he became a Senior Fellow. In the year 1862 he became Vice-Provost, and in 1867, when the Provostship became vacant by the death of Dr. Macdonnell, he was chosen by the Government of the day to fill the place. He con- tinued to discharge the duties of this important office with unwearied assiduity till his death, which occurred, after a few days’ illness, on the 17th of Jannary, 1881. Dr. Lloyd was President of the Royal Irish Academy from 1846 to 1851, and on the visit of the British Association to Dublin, in 1857, he was elected to the Presidency of that distinguished Society. In 1856 the University of Oxford conferred on him the degree of D.C.L., Honoris Causa, and in 1874 he received from the Imperial Government of Germany the Cross of the Order “‘ Pour le Mérite.” Dr. Lioyd’s most important contributions to science were made in the departments of optics and magnetism. It will be convenient to consider these subjects separately, taking the contributions to each subject respectively in the order of time. His first contribution to optical science was a systematic work on plane (as distinguished from physical) optics. It was entitled “ A Treatise on Light and Vision,” and was published in the year 1831. This book possesses a high scientific value. The year 1832 was distinguished in Dr. Lloyd’s life by, perhaps, his most .remarkable single scientific achievement, namely, the experi- mental proof of the phenomenon of conical refraction. The discovery of conical refraction presents one of the instances—rare in the history of physical science—in which theory was able not merely to account for a phenomenon but to predict it. Reasoning mathematically on the theory of Fresnel, and giving a suitable physical interpretation to the mathematical results which he obtained, Professor (afterwards Sir William) Hamilton deduced the remarkable consequence that, in certain cases, the two rays into which an incident ray is usually divided by a crystal are replaced by an infinite number of rays, form- ing a luminous cone or cylinder. Anxious to submit this extra- ordinary result to the test of experiment, he requested Dr. Lloyd to undertake the experimental investigation of the phenomenon, It would be impossible to give here a detailed account of the difficulties attendant upon this inquiry. Suffice it to say that they were over- come by the experimental ability of Dr. Lloyd, who succeeded in giving a perfect experimental demonstration of this remarkable pheno- menon in both its varieties. He also established experimentally the law by which the polarisation of the rays composing the luminous cone is governed. This successful investigation at once brought Dr. Lloyd to the front XX111 rank among the cultivators of optical science, and in the year 1833 he was requested by the British Association to report on the condition of physical optics. The report prepared in compliance with this request was laid before the British Association in the year 1834, and may be regarded as a handbook of the progress of the science to that date. Shortly after the publication of the experiment which established the reality of conical refraction, Dr. Lloyd described to the Royal Irish Academy an important experiment upon the interference of light proceeding directly from a luminous source with light coming from the same source, but reflected at a very high angle of incidence from a plane surface. By means of this experiment he was able to make an important contribution to the theory of reflected light. The phenomena of thin plates require us to admit that a semi-undulation is gained or lost by the light in the process of reflexion at one of the surfaces. But these phenomena do not decide the question whether this modification takes place at the surface of the rarer or of the denser medium. Dr. Young had given the preference to the former of these alternatives ; but Dr. Lloyd derived from the above-mentioned experiment a strong argument in favour of the other. The details of this experiment are published in the seventeenth volume of the “Transactions of the Royal Irish Academy.” In 1836 Dr. Lloyd published the first part of his lectures on the “Wave Theory of Light,” including the phenomena which are inde- pendent of polarisation and double refraction. To this was subsequently added a second part in which the phenomena of polarisation are dis- cussed. A communication received from Sir David Brewster, detailing some remarkable appearances which he had observed in connexion with the phenomena of thin plates, induced Dr. Lloyd to turn his attention to that subject, the light incident on the plate being supposed to be polarised. A communication on this subject was made by him to the British Association in 1841, but the complete investigation of the phenomenon was published in the twenty-fourth volume of the “ Trans- actions of the Royal Irish Academy,” having been laid before that Society in 1859. Assuming the truth of Fresnel’s expressions for the intensity and phase of polarised light reflected from the surface of an ordinary medium, Dr. Lloyd showed that the reflected light is elliptically polarised. He assigned the law of this elliptic polarisation, which passes into plane polarisation where the incident light is polarised in, or at right angles to, the plane of incidence. He also gave the explanation of the phenomena observed by Brewster, where the index of refraction of the plate is intermediate between those of the bound- ing media. But it will probably be felt that the link which associates Dr. Lloyd’s XX1V name most indissolubly with the science of the nineteenth century is to be found in the subject of terrestrial magnetism. It is here that his labours, whether conducted singly or in association with other investigators, have left the most permanent mark; and it is not too much to say that no single individual contributed more largely to the success of the effort which was made to perfect by observation our knowledge of the earth’s magnetic force. At the first meeting of the British Association in 1831, the Com- mittee of Section A reported that it was highly desirable that a series of observations upon the intensity of terrestrial magnetism in various parts of Hngland be made by some competent individual, similar to those which had been recently carried on in Scotland by Mr. Dunlop. In compliance with this suggestion, some experiments were made in the neighbourhood of Liverpool, by W. 8. Traill, M.D., the results of which were laid before the Association in 1832. In 1833 the Committee extended their recommendation so as to include the whole kingdom, appointing as a Standing Committee, charged with the promotion of these objects, Professors Christie, Forbes, and Lloyd. At the same time Dr. Lloyd undertook to make the required observations in Ireland. ‘These observations were carried on in the year 1834 by Dr. Lloyd, with the assistance of Captain (afterwards Sir Edward) Sabine, and subsequently of Captain (afterwards Sir James) Ross. 4,, sho) 250 toma? 5000 of the volume of the liquid. The spectrum was continuous. Terebenthene, from French turpentine. Boiling-point 156-157", specific gravity at 0° C.=0°876, 100 millims. rotate the polarised ray 274° to the left.—The transmitted mane were men the same as before. Slntions containing 35, 745 odo roo» and sano of their volume of the substance were examined. Hesperidene, from Portugal essence. Boiling-point 176-177°, specific eravity at 0° C.=0°859, 100 millims. rotate the polvnaad ray 96° tothe right.— Dilute solutions containing ~3,5, 34>, and sj/5n of their volume of the liquid were photographed. The four diagrams drawn from the photographs obtained from these substances show the rays transmitted by 15 millims. of the liquid alone and when diluted; all rays to the right of the curves are those absorbed by the liquid, while those to the left are transmitted. * This substance has been shown to be chiefly camphene. See “J. Chem. Soc.,” Trans., Vol. 35, p. 758, 1879.—W. N. H., June, 1880. Examination of Essential Oils. 3 The general similarity of the curves is a noticeable feature as well as the intensity of the absorption of the extremely refrangible rays. Diaq@Rams 1—4. Showing the rays transmitted after dilution with various proportions of alcohol. Isomeric Terpenes. 2352425 26 HESPERIDENE The ordinates represent the proportions of alcoholic solution containing one volume of the terpene. Thickness of the layer of liquid = 15 millims. Tt will be seen too that australene and terebenthene show slightly different curves, the latter being rather less diactinic when diluted 100 and 500 times. Another difference between these bodies is that one rotates the polarised ray to the right and the other turns it to the left. The following substances were from Dr. Gladstone’s collection :— Cajputene dihydrate——The main portion of this liquid boiled at 173° C., and none distilled over below the temperature of 170°. Solu- tions containing =1., Zo00> sooo Were examined. An absorption, EB? —- bat 4 Prof. W. N. Hartley and A. K. Huntington. caused, it was afterwards found, by a slight QUEST Be of cymene was noticeable. (Diagram 5.) DIAGRAM 5. Oil of Indian geranium and two samples of the carraway hydrocarbon give the same spectrum. LINES OF CADMIUM... 17 18. 252425. 26 27 Cajuputene dihydrate exhibits the cymene absorption band at =4,. The lign aloe spectrum lengthens out very considerably, but feebly, at =3,>. The ordinates represent the proportions of alcoholic solution containing one volume of the oils. Thickness of the layer of liquid = 15 millims. Oul of Ingn Aloe.—This substance had no definite boiling-point, but distilled over between 185° and 200°, leaving a thick yellow resin in the retort. It was examined after diluting 1,000, 2,000, and 5,000 times. (Diagram 5.) Carraway Hydrocarbon, No. 1.—This smelt like turpentine when dis- tilled. The original label stated its specific gravity to be 0°8545. It boiled between 173° and 178°. The solutions examined contained and so95 Volume of the liquid. (Diagram 5.) Oil of Indian Geranium, from Dr. Piesse.—This yielded the same result precisely as the carraway hydrocarbon. It was not re-distilled. (Diagram 5.) Otto of Rose, from Mr. Farries.—The specimen was solid and crystal- lised in beautiful thin lamine. It was not re-distilled. Solutions containing =7),5 and 3,455 of the volume of the melted substance were examined. (Diagram 5.) Santal Wood Ovl. Boiling-point 277°.”* (Dr. Gladstone.)—The first fraction obtained on distillation was returned to the original bottle. The second part, which boiled between 277° and 287°, but chiefly be- tween 277° and 280°, was the largest portion. The remainder distilled between 287° and 297°. To00 * Quotation from original label. Haeamination of Essential Oils. 5 This substance withstands a large amount of dilution without great alteration in its strong absorptive power. It was examined when diluted 1,000, 5,000 and 20,000 times. (Diagram 6.) DIAGRAM 6. Carraway, cedrat, and santal wood oil give the same spectrum between zy'55 and ; LINES OF CADMIUM 9/01 12 /7 /8 28 2425 26-27 The ordinates represent the extent of dilution of one volume of the various cils Thickness of the layer of liquid = 15 millims. Cedrat Oil (Dr. Gladstone).—This substance had no constant boiling- point; it distilled between 190° and 245°, yielding a yellow vapour and a thick yellow liquid, while a non-volatile yellow resin remained in the retort. Examined after dilution to 1,000 and 5,000 times its 6 Prof. W. N. Hartley and A. K. Huntington. original volume, it was found to possess exactly the same diactinic quality as santal wood oil. (Diagram 6.) “Carraway Hydrocarbon. Boiling-point 350° F., specific gravity 0°8466,.”* (Dr. Gladstone.) No. 2.—The portion boiling above 173° C. was photographed. This substance, diluted to 1,000 and 5,000 times its volume with alcohol, yielded the same results exactly as the former sample and the oi! of Indian geranium. (Diagram 6.) Oil of Birch Bark (Dr. Piesse).—The specimen was not re-distilled. It showed a strong absorptive power until diluted to 4,000 times its own volume; from this point till an additional dilution of 8,000 volumes had been reached its diactinicity rapidly increased. (Diagram 6.) Menthole. Boiling-point 225° C. (Dr. Gladstone.) Prepared from mint oil by means of the hydrosulphate.—After repeated distillations, during which water separated from the first portions, the greater part of the liquid boiled at 215° to 220°. This substance is remarkably adiactinic ; even after diluting 20,000 times all rays from the line 18 Cd onward were absorbed. (Diagram 6.) Oil of Juniper (Mr. Farries).—This was not re-distilled. When diluted 1,000 times, it transmitted very few of the rays beyond line Cd 12. When diluted 10,000 times it transmitted the spectrum as far as Cd 24. (Diagram 6.) Oul of Rosemary (obtained from Italy by Dr. Gladstone).—It boiled between 180° and 200° C. When diluted 1,000 times it fails to trans- mit the rays near line Cd 17, but there is a steady increase in trans- parency on diluting 2,000, 4,000, and 10,000 times. (Diagram 6.) “* Oil of Rosewood. Boiling-point 480° F., specific gravity =0°9042.”* —(Dr. Gladstone.) This is one of the polymerised terpenes, C,;Ho,. It was found to boil at 250° C., yielding a pale yellow distillate. It iereased rapidly in transparency on dilution from 50 to 2,000 times, after which stage up to 20,000 times the transparency did not greatly increase. (Diagram 6.) Nutmeg Hydrocarbon.—This is the specimen specially referred to in Dr. Gladstone’s paper. A few crystals resembling camphor were found in the bottle. The liquid was poured off from these. The first distilled fraction condensed in a turbid state and contained water. It boiled between 159° and 162°°5. The second fraction, equal to one-third the whole quantity of liquid, boiled between 162°5 and 164°. The . other three fractions boiled at temperatures ranging between 164° and 202°, and in addition to these portions there remained a solid residue. On dilution 1,000 and 5,000 times it proves to be amongst the most diactinic of such substances. (Diagram 7.) Oil of Lavender (Mr. Farries).—It boiled between 170° and 180° C. This oil was very soluble in aqueous alcohol, which at once shows it to be perfectly free from turpentine. (Diagram 7.) * Quotation from original label. Examination of Essential Oils. 7 Dracram 7.—Calamus.—-The spectrum beyond Cd 12 transmitted by a dilution of 1 was abnormally feeble. 20000 Nutmeg hydrocarbons.—Specimens referred to in Dr. Gladstone’s paper on “ Es- sential Oils.” No. 1, B.P. 162°5—164°. No. 2 contains a trace of cymene. LINES OF . CAQM/U/7 - 9/01 12 232425 - 26 27 Ze, Ve 8 Prof. W. N. Hartley and A. K. Huntington. Dilution 1,000, 2,000, 4,000, and 5,000 times yields a series of solu- tions from which a remarkable curve may be traced, the lengthening of the spectrum being very rapid between the two last points. Cedrat Hydrocarbon. (Dr. Gladstone.) Boiling-point 173° to 175°.— Dilution to 1,000, 2,000, 5,000, and 10,000 times yielded a curve some- what similar to, but less striking than, that derived from the photo- oraphs of oil of lavender. (Diagram 7.) Oil of Vitivert (Dr. Gladstone).—Two fractions of this substance were distilled off the specimen, which was small in quantity. The first part contained a little water, and the oil was yellow; the second portion was of a peculiar greenish tint, doubtless because of the presence of some blue oil common to camomile and patchouli being here in presence of a yellow oil. A brown resinous mass was left in the retort. The fraction photo- oraphed boiled between 280° and 285°. This is one of those sub- stances which still absorb some of the more refrangible rays even when diluted 30,000 times, while a dilution of 10,000 transmits no- rays beyond the line 18 Cd. (Diagram 7.) Oil of Turpentine. No. IV in Dr. Gladstone’s paper, “ Journal of the: Chemical Society,” vol. xviii, p. 18.—This substance had become greatly altered by keeping. Its original boiling-point was 160° C. It had oxidised and no doubt become polymerised, since many fractions with high boiling-points were distilled off. The following are the boiling-points of different portions of the _ entire distillate :— 150-—160°, contained water. 160-165, _..,, AGS 21808, 12 : 1309052, 205—228°, slightly facbide 228—310°, the greater portion boiled between 238° and 280°. 310—365°. At 320° the liquid was greenish in colour, and at 365° a yellowish- green vapour was evolved. The oxidised products evidently split up by the action of heat with the production of water and a hydrocarbon. The fraction boiling between 228° and 310° was very much more soluble in alcohol containing 30 per cent. of water than that with a boiling-point of 160—165°. The fraction boiling between 228° and 310° did not transmit ray 12 Cd when diluted 1,000 times, and the spectrum was cut off at line 17 Cd, after diluting with 10,000 volumes of alcohol. The fraction boiling above 365° did not differ much from the pre- ceding till a dilution with 10,000 volumes of alcohol was reached. Examination of Essential Oils. 9 The spectrum, however, terminated a little beyond 18 Cd only after diluting 30,000 times. (Diagram 7.) Oil of Cubebs (Mr. Farries).—There were two portions of this oil, one boiling at 260—265°, the other between 266—275°. The first was examined, when diluted 1,000 and 5,000 times; the second portion after diluting 5,000, 10,000, 20,000, and 50,000 times. As far as line Cd 17 the spectrum was freely transmitted, but a dilution of 10,000 times only feebly transmitted the more refrangible rays. (Diagram 7.) Oil of Calamus (Dr. Gladstone).—This oil belongs to the group of substances with the formula C);H,,. The portion boiling at 260° was photographed. It yielded spectra after diluting 1,000, 10,000, 20,000, and 30,000 times, and throughout exhibited the same absorp- tive power, or nearly so, as that displayed by the oil of turpentine of highest boiling-points. (Diagram 7.) Otto of Citron (Dr. Gladstone).—On the second distillation, two: fractions were separated: the first boiled between 110° and 200°, the distillate containing at first a little water; the thermometer then rose rapidly to 200°. The second fraction boiling between 200° and 245° was photographed. This is one of those substances exhibiting a strong absorption, even after dilution with alcohol to 20,000 times its original volume. (Diagram 7.) Oil of Patchouli. No.1. (Obtained by Dr. Gladstone from Mr. H. Atkinson. )—On distillation, the three principal fractions boiled at the following temperatures :— Ist. 250—259°; distillate turbid. 2nd. 259—275°. 3rd. 275—290°; this portion was blue. Ath. 290—360°; this appeared to yield a blue vapour. The second portion was photographed after diluting 1,000 and 5,000 times. (Diagram 8.) Patchouli. No. 2.—This blue oil was rectified, and the portion boiling between 275° and 277° was photographed after diluting 5,000, 8,000, 10,000, and 50,000 times. A very distinct absorption band was noticed lying between lines 12 and 17 Cd. (See diagram.) Perfect transparency to the more refrangible rays was not obtained by a dilution with 50,000 volumes of alcohol. This blue oil may be considered a benzene derivative, since it yields an absorption band be- tween the lines 12 and 17 Cd., and is highly coloured.* (Diagram 9.) Oil of Patchoul. No. 3. ini 1 2000? * All organic colouring matters of which the constitution is known are benzene derivatives in the sense that naphthalene and anthracene are benzene derivatives.— W.N. H. 10 Prof. W. N. Hartley and A. K. Huntington. 1 1 1 = C = 2 a Las soso) Fone? aud sohes Of this oil were taken. It is remarkable for its strong absorption, though it shows no band. (Diagram 8.) DITAGRAM 8. CADM/UM /2 OG : = rare Nes PATCHOULI Noe (THE. BLUE = oll) BR 2752277° a DIAGRAM Q. Oil of Citronella. (From Penang. Dr. Gladstone.)—Two fractions were distilled off at the following temperatures :— Ist. 230—260°. 2nd. 260—300°. The first portion was photographed undiluted, diluted 2,000 and 5,000 times. (Diagram 8.) Oil of Elder (Dr. Gladstone).—This oil boiled between 168° and 175°. The oil itself and solutions containing 335, zoho, and son, were examined. (Diagram 8.) Oil of Melaleuca Hricifolia (Dr. Gladstone). Boiling-point 170— 180°.—Faintly yellow. Photographs were taken after diluting to 500, 1,000, 2,000, and 5,000 volumes. (Diagram 5.) Examination of Essential Oils. st Oil of Cedar Wood (Dr. Gladstone).—There was no distillate at any temperature below 250° C., and only a few drops at 260°. Ist fraction, boiling-point 260—265°. PAN, ss 265—270°. This oil, like several others, polymerises easily during distillation ; consequently, a freshly distilled specimen on redistillation leaves a resinous residue in the retort. The portion boiling between 265° and 270° was examined after diluting 1,000, 3,000, 6,000, and 10,000 times. (Diagram 7.) An examination of the diagrams which contain the results of ob- servations on the preceding substances will show that in bodies of the same constitution the absorption of the ultra-violet rays is greater the larger the number of carbon atoms in the molecule. That is to say, the oils with the higher boiling-points such as calamus, patchouli, and the denser turpentine oil, are those which are the least transparent after dilution with alcohol. With two exceptions, none of the substances already examined exhibit absorption bands. The exceptions alluded to are the first specimen of carraway hydrocarbon, which we shall show further on, containing a small quantity of cymene, and the blue oil from patchouli. As we shall have occasion to remark on the evident presence of cymene in several essential oils, it may be convenient to give an account of specimens of cymene which we have examined, and direct attention to the absorption bands which are made to appear by diluting the liquid to various degrees, as shown in the diagram. Cymene No. 1.—This specimen was prepared by Dr. C. R. A. Wright, and examined optically by Dr. Gladstone. Its source was probably oil.of lemons. It began to distil at 172°, and nearly all the liquid came over below 176° C. The portion boiling between 173° and 175° was completely soluble in fuming sulphuric acid with only a pale brownish coloration. It was examined first without dilution, and subsequently when diluted to 1,000, 2,000, 4,000, 5,000, 8,000, 20,000, 50,000 and 100,000 volumes. Three well-defined absorption bands are visible with a dilu- tion of 4,000 and 5,000 times; a band similar to that lying below the .line 17 Cd appears to be characteristic of the hydrocarbons derived from benzene. See diagrams of benzene, ethyl-benzene, mesitylene, toluene, &c., in Part II of this research (“ Phil. Trans.,” Part I, 1879). (Diagram 10.) Cymene No. 2.—About 250 grms. were obtained from Mr. Kahlbaum’s agents. The boiling-point of nearly the whole of it lay between 173° and 176°. No portion of this was so pure as the 12 Prof. W. N. Hartley and A. K. Huntington. preceding specimen. When diluted 2,000, 4,000, and 5,000 times it exhibited absorption bands coinciding with those shown in No. 1. These bands are noticeable in the carraway hydrocarbon. DiaGRam 10. ‘(CH CYMENE GZ; CH, CH, The following specimens of essential oils and hydrocarbons prepared therefrom all exhibit absorption bands. Thyme hydrocarbon. Oil of bergamot. Lemon he Myristicol. Nutmeg - Oil of cloves. Oil of bay. Oil of aniseed. Otto of pimento. Carvol. Oil of thyme. Oil of cassia. Oil of peppermint. In the case of the hydrocarbon from thyme, lemon, and nutmeg, it is the presence of cymene which causes an intermediate absorption in Examination of Essential Oils. 13 the spectrum. In other cases absorption bands are present because the oil itself is largely composed of some other benzene derivative. Thyme Hydrocarbon. No. 2. (Dr. Gladstone.)—After careful dis- tillation and fractioning, there were two portions which boiled at 161—1638°, and 163—170°. A considerable quantity derived of course from the first fractions boiled between 162° and 163°, and was taken as the representative of the pure substance. The liquid diluted to 50, 500, 750, 1,000, 1,500, 2,000, 4,000, 8,000 and 16,000 times its original volume was examined. (Diagram 11.) | DracrRamM 11. Thyme hydrocarbon. (Dr. Gladstone.) poet £2 /7 This absorption is due to the large amount of cymene contained in the liquid. The curve shown is interesting, because it enables us to make an approximate estimation of the proportion of cymene contained in the hydrocarbon, for since the absorption exhibited when the dilution to zis coincides as nearly as possible with that given by cymene at app) lt is evident that the thyme hydrocarbon must contain about + its volume of thisliquid. The rounding off of the more refrangible portion of the spectrum is a modification caused by the terpene. “* Hydrocarbon from Oil of Lemons.—Boiling point 343° F., specific gravity 0°8468 at 20° C.”* (Dr. Gladstone.) * Quotation from original label. 14 Prof. W. N. Hartley and A. K. Huntington. Nearly the whole of this specimen boiled between 173° and 175° C. Photographs were taken after diluting 50, 1,000, 2,000 and 4,000 times. The cymene absorptions are seen at 5, and 5,5, and indicate that about + of the volume of the original liquid consists of this body. (Diagram 12.) DraGRam 12. Hydrocarbon from oil of lemon. (Dr. Gladstone.) The absorption due to cymene is well seen in this specimen. Hydrocarbon from Oil of Nutmeg.—Specimen No. 2. (Dr. Gladstone.) A very considerable quantity distilled at 167°, and as the boiling- point did not rise, a portion of this was taken for examination. Solutions containing 735, zo5o5) aaoo and ages of the liquid were examined. It showed the cymene absorption. (Diagram 13.) The DiaGRAmM 13. Nutmeg hydrocarbon. B.P.167°C. Absorption due to cymene. diagrams of course vary a little in appearance according to the number of solutions photographed, and of course in these particular cases by the proportion of cymene present; hence the diagram repre- senting the absorption in the case of the thyme hydrocarbon gives the best idea of the modification of the terpene spectrum caused by an admixture of cymene by reason of the greater number of photographs employed in depicting it. Examination of Essential Oils. 15: Substances causing strong absorption bands in the spectrum transmitted by dilute solutions. The following oils and derivatives of essential oils show strong absorption bands in their photographed spectra. For the most part they are bodies known to contain the aromatic nucleus as an essential part of their constitution. Thus the oils of bay, pimento, and cloves contain the substance eugenol, C,H,.0H.OCH3;.C,H. ; oilof cassia con- sists of cinnamic aldehyde, C,H..C,H,.COH; and oil of aniseed contains anethol, C,H,.OCH, C3H.;; and oil of thyme, thymol, C,H,.0H;.C,H Some other oils, such as bergamot and oil of peppermint, as like- wise the bodies menthole, carvole, and myristicol, have an unknown constitution. The three latter substances are known to be isomeric. (“ Journ. Chem. Soc.,” Gladstone, vol. xxv, p. 1.) Great interest is attached to our examination of these, since we con- sider it to be proved from the character of the spectra they transmit, that the nucleus of menthole is a terpene, while the benzene ring is the inner basis of carvole and myristicol. Bergamot appears to be a terpene mixed, with some derivative of the aromatic series, but oil of peppermint on the other hand is essentially a substance belonging to the latter class. Oil of Bay (Dr. Gladstone).—There was a fair quantity of this substance, and the following fractions were separated by distilla- tion :— Ist fraction boiling at 190—200° C. ond 200-2202 , Srd . 200 o4n2. 4th i 240—260° ,, The two principal fractions boiling at 190 to 200°, and from 220 to 240°, were photographed. The fraction bois between 190—200° solutions containing = sooo ise00 2nd sgt55 «Were examined. The first absorption bana commenced midway between lines 12 and 17 Cd, and in a solution containing =3,; of the oil, this continues. nearly to the line 18 Cd; at this point a narrow band of rays is trans- mitted. The widening out of this band is somewhat rapid between S000 and yoOq9> after which it is somewhat more gradual, there being still some absorption at 1 in 50,000. The fraction boiling between 220—240° solutions containing | in 1,000, 5,000, and 10,000 were photographed. The absorption in these solutions appears at nearly the same points, but is moreintense. This is quite what one might expect supposing the fraction with the higher boiling-point to contain a greater proportion of the absorbing body than the other. T000 16 Prot. W. N. Hartley and A. K. Huntington. DIAGRAM 14. Oil of bay. (Dr. Gladstone.) Fraction boiling at 190—200°. Absorption here is visible at =,1,5. Diagram 15. Oil of bay. Fraction boiling at 220—240°. Absorption here is visible in a solution containing -57,55- It is evidently due to O eugenol, CsH3(OH) are Compare with oil of cloves. Examination of Essential Oils. 17 There can be little doubt but that eugenol is the cause of the absorp- tion in both cases. Otto of Pimento (Dr. Gladstone).—The bulk of the liquid, consist- ing of some 5 or 6 fluid ounces of the oil, boiled between 238° and 241°. Hugenol has been shown by Bonastie to be contained in otto of pimento, and its boiling-point is said to be 242° (Stenhouse), 243° (Httling), 248° (Briining), and 251° (Greville Williams). (Gmelin, English edition, vol. xiv, p. 202.) We may consider, therefore, that the characteristic spectrum of this otto of benento to a due to pugenol. Solutions containing 7955, soso todos zotow Fosop and zoo000 Were photographed. (See Diagram 16.) Diagram 16. Otto of pimento. Absorption due to eugenic acid. See oil of cloves and of bay. 5B 2 neseze 2425 26 26 27. —— — —— —— = eet —= === Oil of Cloves (Dr. Gladstone).—The following fractions were ob- tained on distillation :— VOL. XXXI. c 18 Prof. W. N. Hartley and A. K. Huntington. No. 1 boiled between 247 —250°. 93 2 99 250— OS ee i 200 we », 4 boiled above 300°; a brown resinous residue was left in the retort. The second fraction distilled almost entirely between 250° and 253°. DIAGRAM 17. Oil of cloves. (Dr. Gladstone’s specimen.) The absorption band is evidently due to eugenol, C;,H3(OH) seat 9101 l2 es 25 Absorption still seen at 1 in 50,000. Oil of cloves contains a small portion of a hydrocarbon, C,;H,,, together with eugenol (Httling, “Ann. Pharm.,” 9, 68, also Gmelin, English edition, vol. xiv, p. 92), The boiling-points of the hydro- carbons with the formula C,;H,, lhe between 249° and 260°. It is therefore extremely improbable that the hydrocarbon could be sepa- EHxamination of Essential Orls. 19 rated from the eugenol by distillation. As we desired to examine the oil of cloves in its usual state, we did not attempt to separate the eugenol by means of alkalies. That portion boiling between 250° and 253° was examined after diluting 1,000, 5,000, 10,000, 20,000, and 30,000 times. A characteristic absorption, similar to that of otto of pimento, was remarked. (Diagram 17.) Oil of Aniseed (Dr. Gladstone).—By far the greater portion of this oil distilled readily between 220° and 223°, and was very easily crystal- DIAGRAM 18. Oil of aniseed. B.P. 220—223° C. The absorption band is due to anethol, OCH CsH 3 Absorption still strong at 300,000. lised at a little below 12°. A portion, boiling between 220° and 223°, was examined. Photographs were taken of solutions containing +355, : : : : : 10000? 20000? SUDO? TO000d) ZODGGG Fod000 Of the oil. The intensity c2 20 Prof. W. N. Hartley and A. K. Huntington. of the absorption exerted by this substance is extraordinary, and we may no doubt regard it as being very nearly pure anethol or allyl- phenol-methyl ether. (See Diagram 18.) Oil of Cassia (Dr. Gladstone)—This specimen began to distil at 130° C., but the thermometer rose at once to 250° and then slowly continued upwards to 280°, the distillate being bright yellow. The remaining portion was a brown resin. The portion boiling between 250° and 280° was dissolved in 1,000, 5,000, 50,000, 75,000, 100,000, and 150,000 parts of alcohol, and examined. (See Diagram 19.) Diagram 19. Oil of cassia. B.P. 250—280°. The absorption band is due to cinnamic aldehyde, C)H,OH. Absorption band very faint at 150,000. The absorption is remarkably intense up to the dilution of 1 in 50,000, when a band of rays is transmitted adjacent to the position of Eaamination of Essential Oils. 21 the line Cd 23. The absorption disappears as this band widens out by reason of further dilution. Since oil of cassia consists mostly of cinnamic aldehyde, which has the composition C,H..C,H,.COH, the aromatic nucleus is here again accountable for the absorption. Oil of Thyme (Dr. Gladstone).—Nearly the whole of the specimen distilled between the temperature of 220° and 240° C. A brown resinous residue remained in the retort. Portions of the oil were examined in solutions containing Diagram 20.) 1 Tee. 1 1 1000? 5000? 10000? and Z0000° (See DiacRam 20. Oil of thyme. Portion boiling 220—240°. Absorption due to thymol. A characteristic absorption may be traced to the presence of thymol, a substance already examined with other benzene derivatives. (See Part II of this research.) Carvol (Dr. Gladstone). Separated from oil of carraway by distil- lation.—The liquid distilled almost entirely between 215° and 220°. The portion boiling between these temperatures was examined after dilution 1,000, 10,000, 100,000, 120,000, 150,000, 200,000, 250,000, and 300,000 times its volume with alcohol. (See Diagram 21.) The absorptive power of this body is remarkable, and is undoubtedly 22 Prof. W. N. Hartley and A. K. Huntington. due to its containing a nucleus of three doubly-linked carbon atoms. {ts refraction equivalent is abnormal, like those of bodies of the aro- matie series. (Gladstone, ‘“‘Chem. Soc: J.,” vol. xxii, p. 149.) Fur- thermore it is isomeric with cuminic alcohol and thymol. DIAGRAM 21. Carvol. B.P. 215—220°. C\H\,0. Separated from oil of carraway by distillation. * The absorption still very considerable. These specimens were from Dr. Gladstone’s collection. Myristicol (Dr. Gladstone).—Derived from oil of nutmegs. On this substance being distilled, there were two principal fractions: No. 1, boiling below 215° C. NOP 23) se tromea lo rtor2o Ue The second portion was the better and much the larger part of the liquid. The liquid diluted 1,000, 5,000, 10,000, and 15,000 times, was photographed. The character of the absorption is such as to Examination of Essential Oils. 23: make it probable that this is a mixture of a terpene with a large amount of some benzene derivative. DIAGRAM 22. Myristicol. When a mixture of two substances exhibits absorption bands which _ are due to only one of them, the following characters are generally noticeable :—I1st. There is not unfrequently a haziness about the transmitted rays; 2nd. The absorption bands are not well defined ; érd. A comparatively limited amount of dilution suffices to obliterate the chief features of the absorption spectrum. All these points may be to some extent observed in the spectra of this myristicol, but the bands are yet so strong that they evidently belong to the predominant compound. On referring to the refractive equivalent of myristicol (Gladstone, Chemical Society’s Journal, vol. xxiii, p. 149), we find that it corre- sponds well with numbers characteristic of compounds of the aromatic series. Hence, the conclusion is obvious, that the greater part of the liquid consists of some benzene derivative. Oil of Bergamot (Dr. Gladstone.)—This oil was separated into two fractions :—1st, boiling between 175°. and 180° ; 2nd, between 180° and OO. The first portion was diluted to 400, 800, and 1,000 times its own volume, and photographed. An absorption band was noticed, which soon became removed by dilution, and therefore was set down to an impurity. (See Diagram 23.) 24 Prof, W. N. Hartley and A. K. Huntington. DIAGRAM 23. Bergamot. 72 Wo S8 232425. 26.27 .' DIAGRAM 24. Oil of bitter almonds. ~ Examination of Essential Oils. 25 Oil of Bitter Almonds (Dr. Piesse).—Solutions in 1,000, 5,000, 10,000, 50,000, and 100,000 volumes of alcohol were examined. A highly characteristic absorption distinguishes this substance. As is well known, it is the aldehyde of benzoic acid. (See Diagram 24.) DIaGRAM 25. Oil of peppermint. B.P.198—215°. (Dr. Gladstone.) 23 25 26 27 /7 /8 Oil of Peppermint (Dr. Gladstone). B.P. 198—215°.—This is ob- tained by distilling Mentha piperita. Dr. Gladstone states that both the English and Italian specimens examined by him contained a hydrocarbon which has physical properties differing little from those of the hydrocarbon from bay. It will be seen, however, that the absorption spectra due to these two substances are very different. The following is a summary of our conclusions with regard to the terpenes :— 1. Terpenes, with the composition C,)H,,, possess in a high degree 26 Dr. C. A. MacMunn. Researches into the the power of absorbing the ultra-violet rays of the spectrum, though they are inferior in this respect to benzene and its derivatives. 2. Terpenes, with composition C,;H,,, have a greatly increased absorptive power. 3. Neither the terpenes themselves nor their oxides nor hydrates, exhibit absorption bands under any circumstances when pure, but always transmit continuous spectra. 4, Isomeric terpenes transmit spectra which generally differ from one another in length, or show variations on dilution. 5. The process of diluting with alcohol enables the presence of bodies of the aromatic series to be detected in essential oils; and even in some cases the amount of these substances present may be approxi- mately determined. Researches into the Colourng-matters of Human Urine, with an Account of the Separation of Urobilin.” By Cuas. A.. MacMunn, B.A., M.D. Communicated by A. GAMGEE, M.D., F.R.S., Brackenbury Professor of Practical Physio- logy and Histology in Owens College, Manchester. Re- ceived March 6, 1880. Read March 18, 1880. I do not propose to discuss in this paper all the pigments which have been said to occur in urine, as their consideration would extend. over a considerable space; and I shall, therefore, hmit my observa- . tions to those which I have myself studied, and which are discoverable. by means of spectroscopic observation. Notwithstanding the efforts of physiological chemists, at home and abroad, no one has been hitherto able to isolate the pigment known as urobilin. After many unsuccessful attempts, I have at length succeeded in isolating a pigment, which, on account of its spectroscopic and chemical re- actions, appears to be urobilin in a pure state. Although it has not been obtained in sufficient quantity to allow of a formula being assigned to it, I believe that I shall soon be able to: obtain enough for this purpose. A preliminary examination has. shown that it contains carbon, hydrogen, oxygen, and nitrogen. Preliminary Remarks.—lf nitric acid be added to a solution of bile before the sht of the spectroscope, the solution at once undergoes. a change of colour, becoming green, blue, violet, red, and, lastly, yellow or brownish-yellow, and the spectrum is characterised by having two bands: a broad shadowy band, composed of two in orange and yellow, and a black band at Fraunhofer’s line F. Ina short time the shading in orange and yellow begins to fade, and at the time the oxidation process is completed, and the colour of the solution Colouring-matter of Human Urine. 27 has become yellow, nothing but the band at F is left. Jaffé (“‘Zeitsch. f. Chem.,” v, 666) succeeded in isolating the pigment which gives the feeble bands on each side of D, and also that which gives the band at F. The pigment which gave this last band, when isolated, was brown-red in colour, soluble in alcohol, ether, and chloroform; the solutions Ti l Hi HHH Wt) Wit Figure reduced from Chart I. (See p. 36.) being a fine red colour, giving, when acidulated, a dark band at F. By treating a solution of dog’s bile with hydrochloric acid, the same observer obtained a red fluid, which became yellow on the addition of alkalies, and which, before alkalies were added, was marked by giving the same dark band as before, but after the addition of alkalies, especially caustic soda, this band was replaced by another one nearer the red. Since Jaffé described these appearances, Maly* has asserted * “ Ann. Ch, Pharm.,” clxi, p. 368; elxiii, p. 77. ¢ 28 Dr. C. A. MacMunn. Sesearches into the that he can produce urobilin, or, as he called it, hydrobilirubin from bilirubin, the red colouring matter of human bile;* and, although his researches have been called in question by some physiological chemists who profess to have repeated his experiments with a negative result, yet the conclusions drawn by him are practically correct, and have led, in my hands, to the discovery of urobilin in the bile of various animals, in human urine, and to its complete isolation from the latter fluid. | Most specimens of high-coloured urine, provided the high colour is not due to blood or unchanged bilirubin or biliverdin, show, when examined with the spectroscope, a dark band at I’, which disappears completely when the urine is treated with ammonia, and which is moved towards the red end of the spectrum by treatment with solution of caustic soda. The band can be made to reappear after the am- monia treatment by the addition of nitric, hydrochloric, or acetic acid. Since almost all specimens of urine which I examined showed a band at F, I had concluded that this band was due to urobilin, but f could not account for the fact that ammonia did not always cause its disappearance. I now find that there are two pigments in urine which give a band at F. This discovery was made while I was engaged in studying urobilin, for, on treating normal human urine, which was of a pale straw colour, in the same manner as that adopted for the separation of urobilin, I found a pigment of a brownish colour, which, when dissolved in ether, gave two faint bands, one of which was placed over IF’, the other between b and D (see 18 of figure). The band at F was not made to disappear by ammonia, nor did acids intensify it. As a similar band is found in blood serum, in yelks of eggs, in butter, cheese, &c., which is due to Thudichum’s “lutein,” I see no objection in accepting that author’s name, urolutein, for this pigment. My object in mentioning this is to call attention to the fact that urobilin is not the only pigment which gives a band at F'; but urobilin appears to be the only pigment which behaves on treatment with acids and alkalies in the manner I have described. The presence of this pigment urolutein in urine containing urobilin as well, has also led to the statement which appears in some text-books of physiological chemistry, that caustic soda, when added to urine containing urobilin, causes two bands to appear. The reason is, that caustic soda moves the urobilin band towards the red, but leaves untouched the band of urolutein ; consequently, two bands are seen instead of one. When urobilin alone is present, ammonia causes the complete disappearance of the band at F, and caustic soda moves it towards the red. Accord- ingly, a preliminary examination will enable us to determine whether * By reduction with sodium amalgam and subsequent treatment with hydro- .chloric acid. Colouring-matter of Human Urine. 29 urobilin alone is present, and the neglect of this observation has led to disappointment. Examination of the Bile-Spectra of various Animals.—If urobilin be formed from bile, the question naturally arises, is urobilin present as. such in the bile of any animal? If so, its biliary origin is made more certain. To enable me to reply to this question, I proceeded to examine this fluid in various animals, using in each instance fresh bile, and examining the spectra by means of a Sorby-Browning micro- spectroscope, and checking observations—when the amount of fluid at my disposal was sufficient for the purpose—by means of a one-prism chemical spectroscope. The bile of the following animals was examined :—man, pig, dog, cat, guinea-pig, rabbit, mouse, sheep, hedge-hog, ox, crow, blackbird, chicken, goose, wild duck, duck, frog. Among these animals, the bile of the following gave a characteristic spectrum :—guinea-pig, rabbit, mouse, sheep, ox, crow. The darkest green or golden-red bile gave the least characteristic spectrum. I have fully described, in the “Spectroscope in Medicine,”’ the colour and spectrum of each specimen, but I shall here merely mention those facts which throw light upon the origin of urobilin, namely, that by careful dilution or by examination in a sufficiently thin depth, a band at F is always visible, that this band is made darker by acids, and is made to disappear by adding ammonia. This is very striking in the case of the bile of the mouse (Chart I, sp. 12*), which gives a black band, resembling exactly that seen in febrile human urine. If Chart II be inspected, the most noticeable appearance is the presence of this band in so many spectra. And one cannot help also noticing the general resemblance between these bile- spectra and those shown in the figure, which are the spectra of urobilin in various solutions, and treated by various reagents. I also attempted to extract urobilin from the liver of the pig, by means of various solvents, the pounded liver having been extracted. with water, alcohol, ether, chloroform, and acidulated alcohol re- spectively, but without success. Separation of Urobilin from Human Urine.—Before describing the method which I adopted for the separation of urobilin, I may make one er two preliminary observations. The reagents used were perfectly pure, and pure ethyl alcohol was used in every instance; this is a matter of great importance, as methylated spirit is not suitable for the separation of such easily decomposed bodies as urobilin. The readings of the spectra are those of a photographed scale adapted to the micro-spectroscope; and before taking the readings, the precaution was always adopted of narrowing the slit until the sodium * The Chart II referred to above is reproduced in the “Spectroscope in Medi- eine ;”’ and accordingly does not accompany this paper. 30 Dr. C. A. MacMunn. Researches into the line stood at the same number on the scale. Of course this would have been unnecessary if the jaws of the slit had been made to open equally. The readings are also given in wave-lengths, the latter having been calculated by means of an interpolation curve; they are expressed in millionths of a millimetre. Since preliminary observation had shown that there are two pig- ments in urine which give a band at F, it was necessary, if possible, to get a specimen of urine which contained urobilin only. Accordingly, the urine of a case of phthisis was chosen, which gave the band at F, in very slight depths; this band could be made to disappear by ammonia, and was moved towards the red by caustic soda. The colour of the urine was orange-red. The urine therefore contained urobilin, and on six different occasions I separated urobilin by the following method from it; on each occasion the result was the same. I may mention that no play of colours was produced by nitric acid (containing nitrous. ) Hzperiments—230 cub. ceutims. of urine was precipitated by neutral lead acetate, and filtered, the filtrate which still showed the urobilin band was precipitated with basic lead acetate and filtered ; the filtrate now showed no band. The precipitates were united and extracted with alcohol acidulated with sulphuric acid, and again thrown on a filter. The filtrate was a. fine, clear red fluid giving in slight depths a well-marked black band at F. Some of this fluid was put into a separating funnel, a large quantity of water added,and then chloroform; the whole well shaken and allowed to stand, the red chloroform layer separated off and examined, when it was seen to give the same black band. The remainder of the alcohol fluid was treated in the same manner. I had now a fine red fluid, being a solution of urobilin in chloroform, with, however, a little turbidity at its surface, which disappeared after filtration, which was twice repeated. An attempt was made to separate some of the colouring matter from the chloroform with acidulated water, but with a negative result. The chloroform was now distilled off, the residue redissolved in chloroform, which was again distilled off (in both cases over a water- bath). The residue was brown-red in colour, glistening on the surface, perfectly amorphous, and gave, when examined on the stage of the micro-spectroscope, with a strong light condensed upon its surface, a black band at F. It is perfectly soluble in alcohol, chloroform, nitric acid, hydrochloric acid, acetic acid, lactic acid, acidulated water, partially in ether, both ethereal solution and residue when dissolved _ in alcohol, giving same spectrum; partially in benzol and in water ; insoluble in bisulphide of carbon. | The chloroformic solution gives no precipitate with chloride of ‘barium, nor after treatment with ammonia. Colouring-matter of Human Urine. dl Hthereal Solution of Urobilin, got by Sulphuric Acid and Alcohol Method described above-—The colour is dark red. Spectrum— Extent, 10 to 65 (or wave-length 678—-457).: Band ¢, 21 to 23 (or wave-length 604—592.) | g., fiourep. 27 (2). Band 6, 28 to 32 (or wave-length 568—552). ins Band a, 45 to 55°5 (or wave-length 507—479) ° By treating an appropriate depth of this fiuid in a cell with am- monia, the colour becomes lighter and more yellow, and gives the spectrum shown in figure (3). Ataless depth, the band at Fis seen to have disappeared. This band shown in the figure (2) reads from 23 to 29 (or wave-length 592—564). When excess of ammonia was removed by means of a small pipette, and the solution was acidified with acetic acid, the band at F re- appeared. Alcoholic Solution of same Pigment.—This solution was of a red colour, and gave, when examined at a suitable depth, two bands, and at a less depth another black band at F. The readings of the bands at the first depth were as follows :— Extent, 9 to 37 (or wave-length 686—534) Band e, 21 to 23 (or wave-length 604—592) se figure (4). Band 6, 26 to 29 (or wave-length 578—564) Less depth :— Extent, 9 to 7& (or wave-length 686—435) Band a, 45 to 55 (or wave-length 507—480) When the first depth was treated with ammonia, a band appeared reading 25—29 (or wave-length 582—564), and in a slight depth of fluid so treated the band at F had disappeared. This solution then gives the same spectrum as the ethereal solution, the slight differences in positions of bands being due to different re- fractive power of solvent used, and when ammonia was added, the same effect as in the case of the ethereal solution was produced. See figure (6.) Chloroformic Solution.—Red solution, giving in sufficient depth two bands, and in less depth, one band. The readings of the spectrum of first depth were as follows :— Extent, 11 to 40 (or wave-length 671—523) | Band e, 21 to 23°5 (or wave-length 604—590) \ See figure (7). Band 6, 27 to 81 (or wave-length 573—556) The band of the shallower depth read from 44 to 55 (or wave- length 510—480). See figure (8). Treated with ammonia, I got the band shown in figure (9), reading \ See figure (5). 32 Dr. C. A. MacMunn. Researches ento the from 28—s2 (or wave-length 568—552). So that this solution gives practically the same spectrum as the ethereal and the alcoholic. Benzolic Solution.—Reddish solution giving following spectrum :— Extent, 11 to 65 (or wave-length 671—457). Band ¢, 21 to 23 (or wave-length 604—592). Band 6, 28 to 32 (or wave-length 568—552). Band «, 45 to 55 (or wave-length 507—480). This also gave a band near D when treated with ammonia, which also caused the disappearance of band «. At first it seemed possible that the appearance of these bands e¢ and 6 might have been due to the action of heat on the pigment during the evaporation, but on evaporating the chloroformic solution under the receiver of the air-pump the same result was arrived at. Action of Caustic Soda on Solutions.—If the solutions were examined in a depth sufficient to show band at F distinctly and caustic soda were added, in each case this band disappeared and was replaced by another nearer the red. Thus in ethereal solution the band read _42—47 (or wave-length 517—502); and in chloroformic solution the band read 43—48 (or wave-length 513—499); and in alcoholic solu- tion 41:5—47 (or wave-length 519—502. Aqueous Solution.—The aqueous solution gave the black band at F, disappearing with ammonia and moving towards the red with caustic soda. Solution of Pigment in Hydrochloric Acid.—It dissolved completely in hydrochloric acid, giving a red solution, which in a sufficient depth showed a band at D, figure (11). Extent, 9 to 32 (or wave-length 686—552). Band y, 20 to 25 (or wave-length 609—582). In less depth :— Extent, 9 to 63 (or wave-length 686—462). Band a, 45 to 53 (or wave-length 507—485). By the ammonia and caustic soda treatment, the spectra were altered in the same manner as those of the other solutions. Solution of Pigment in Sulphuric Acid.—A red solution. Deep layer :— Extent, 8 to 37 (or wave-length 694—534). Band, 21 to 25 (or wave-length 604—582). Shallower depth :— Extent, 7 to 80 (or wave-length 702—432). Band, 43 to 52 (or wave-length 513—488). As all these solutions contained the same pigment, the next step Colouring-matter of Human Urine. 33 was to determine the elementary composition of this pigment; ac- cordingly the residue from the chloroformic treatment was carefully analysed, when it was found to contain :— Carbon. Hydrogen. Oxygen. Nitrogen. Sulphur. The occurrence of the last element led to the supposition that it must have been due to the treatment with sulphuricacid. I therefore came to the conclusion that if this supposition were correct there would be an absence of sulphur in the pigment prepared by a method in which hydrochloric acid would be used instead of sulphuric. Separation of Urobilin by means of Hydrochloric Acid.—This method was exactly similar to the first, with the exception, that instead of using alcohol acidulated with sulphuric acid, I now used alcohol acidulated with hydrochloric acid, and the pigment was separated on four different occasions; the residue obtained resembled exactly that got by the first method, both as to its appearance and as to its solu- bility in different media. The spectra of these solutions differed (as I expected they would) in regard to the band near D, but that at F’ was exactly the same as before, and acted in the same manner when treated by ammonia and sodie hydrate respectively. I now proceed to the spectra observed in the solutions of urobilin obtained by this method. Alcoholic Solution.—An orange-red solution, which in sufficient depth gave the following spectrum :— See figure Band 6, 18 to 20 (or wave-length 620—609) (13) Extent, 10 to 32 (or wave-length 678—552) Band (feeble) ¢, 22 to 25 (or wave-length 598—582) } Shallower depth :— | Extent, 7 to 83 (or wave-length 702—427) Band, 47 to 54 (or wave-length 502—483) \ Pecmeure Treated with ammonia the colour of the solution became less red, and the following spectrum was seen :— Hixtent, 10 to 40 (or wave-length 678—523) Band 6,15 to 19 (or wave-length 640—614) 4 See figure (15). Band 6, 23 to 26°5 (or wave-length 592—576) In shallower depths the band « of original solution had disappeared. VOL. XXXI. D 34 Dr. C. A. MacMunn. Researches into the Hthereal solution —Of an orange colour. It gave the following spectrum when treated with ammonia :— Extent, 10 to 37 (or wave-length 678—534) Band 6,16 to 20 (or wave-length 634—609) } See figure (16). Band y, 28 to 28 (or wave-length 592—568) In a less depth the band « at F of original solution had disappeared. Chloroformic solution.—This solution gave a similar spectrum to, and was altered similarly by, ammonia as the other solutions just described. Action of Caustic Soda on thése solutions —In appropriate depths caustic soda moves the band at F nearer the red. Thus in the case of the alcoholic solution :— Band before treatment with caustic soda, 47 to 53 (or wave-length 502—485). Band after treatment with caustic soda, 40 to 45°5 (or wave-length 523—506). And the action of caustic soda on the ethereal and chloroformic solu- tions was similar. When urobilin is thus treated with caustic soda, ammonia is no longer capable of causing the band to disappear. Action of Acids on Urobilin prepared as above.—It dissolves in sul- phuric acid, giving a splendid ruby-red solution, having the following spectrum :— Extent, 10 to 40 (or wave-length 678—523). As the bands are uncertain, alcohol was added, when a band appeared from 21 to 25 (or wave-length 604—582), and a very faint shading from 30 to 35 (or wave-length 560—542) see figure (12). (Band at F in shallow depth.) | It dissolves in acetic acid, forming an orange-red solution, giving in suitable depths the following spectrum :— Extent, 10 to 38 (or wave-length 678—530) Band 6, 22 to 26 (or wave-length 598578) Se figure (17). Bandy, 32 to 35 (or wave-length 552—542) Shallow depths :— Extent, 8 to 85 (or wave-length 694—425). Band «, 45 to 55 (or wave-length 507—480). Ammonia develops in this solution three feeble bands :— Extent, 10 to 41 (or wave-length 678—520). Bande, 8 to 11 (or wave-length 694—671). Band 7, very feeble, reading could not be taken. Band 6, 34 to 37 (or wave-length 545—534). Colouring-matter of Human Urine. 35 In a slight depth the band at F had disappeared. The pigment was also soluble in nitric acid and in lactic acid ; in the former there were no bands, except that at F, visible; in the latter they resembled those of the acetic acid solution. All the spectra which I have described will suffice to show that the same pigment was evidently present in every solution; there were many more observed and measured, but they were not of sufficient importance to call for their being mentioned here. It now became necessary to test the urobilin prepared by the hydro- chloric acid process for sulphur, which was accordingly done; and not only was sulphur found to be absent, but the presence of chlorine was detected, showing that my inference was correct, and that the sulphur found in the urobilin prepared by the sulphuric acid process was due to the sulphuric acid used in its preparation, and that the chlorine found in the urobilin prepared. by the hydrochloric acid process was due to the hydrochloric acid. But in neither case was there free sul- phuric acid or free hydrochloric acid, and hence the conclusion follows that the urobilin was in combination with those acids respectively. I think it will be allowed that the bands visible only at certain depths of the solution belong to the same pigment that gives the band at F, hence they all belong to urobilin. As they are not visible in the aqueous solution, we can understand why they are not visible in urine. And I may also mention that, although water only appears to take up a pigment giving a band at F, yet after evaporation of the water and solution of the residue in alcohol, ether, or chloroform, the same bands again become visible. Summary. 1. Urobilin has been separated from urine. 2. It has been separated in combination with hydrochloric acid and with sulphuric acid respectively. 3. The spectra of solutions of urobilin obtained by these methods respectively differ in the position of certain feeble bands, but agree in all having a black band at F, which can be made to disappear on adding ammonia in excess, and which is replaced by another band nearer the red end of the spectrum on the addition of sodic hydrate. 4, Urobilin is an amorphous brownish-red pigment, which contains carbon, oxygen, hydrogen, and nitrogen. It is soluble in alcohol, chloroform, acidulated water, acids; partially in ether, benzol, and water, 7.e., if the pigment be separated in combination with hydro- chloric or sulphuric acid. 5. Urobilin appears capable of existing in different states of oxida- tion. 6. Urobilin is derived from one of the colouring matters of bile. 36 Researches into the Colouring-matter of Human Urine. 7. Urobilin is the colouring matter of the bile of the mouse. Before concluding this paper | should like to call attention to a peculiarity which the band @ of urobilin exhibits: in certain depths it appears very broad, but in less depths it is seen that the portion of the band nearest the violet has disappeared. In other words, the redward part of the band is the most persistent and is the last to disappear on dilution. Thus, taking the alcoholic solution of urobilin prepared by the second process mentioned before, we find that when the extent of the spectrum is 8 to 80 (or wave-length 694—452) this band reads 42—67 (or wave-length 517—453), but when the extent is 7 to 85 (or wave-length 702—425) then the band reads 47 to 53 (or wave-length 502—485.) Urobilin, ike hemaglobin and hematin, appears to be a very unstable body, which easily splits up on treatment with reagents into decomposition products, each giving a peculiar spectrum. This accounts for the differences observed in the spectra obtained by the different methods I have described. EXPLANATION OF FIGURE (p. 27). . Solar spectrum. . Urobilin, prepared by the alcohol and sulphuric acid method, ethereal solution. . The same treated with ammonia. . Urobilin, prepared by the same method, dissolved in alcohol. . Slight depth of the same. . Solution, of which 4 is the spectrum, treated with ammonia. . Urobilin, prepared as in 2 and 4, dissolved in chloroform. . Shallow depth of the same. . Solution, of which 7 is the spectrum, treated with ammonia. Solutions 3, 6, and 9, if examined in a shallow depth, show no band at F. lv. Action of caustic soda on slight depth of solution in 2, 4, and 7. 11. The pigment, prepared by the above method, dissoived in hydrochloric acid. 12. Urobilin, prepared by the hydrochloric acid and alcohol method, dissolved in sulphuric acid ; at a shallower depth we get the band at F. 13. Urobilin, prepared by the hydrochloric acid and alcohol method, in alcoholic solution. COONAN FEWNHN E& 14. Shallow depth of same. 15. Solution mapped in 13 treated with ammonia. 16. Ethereal solution of urobilin, prepared as in 13 and treated with ammonia. 17. Urobilin, prepared by the same method, dissolved in acetic acid. At less depth band at F is seen. 18. Spectrum from residue,—got by treatment adopted for separation of urobilin,— from pale straw-coloured urine. Essential Properties and Chemical Character of Beryllium. 34 November 18, 1880. THE PRESIDENT in the Chair. In pursuance of the Statutes, notice of the ensuing Anniversary Meeting was given from the Chair. General Boileau, Mr. Currey, Mr. De La Rue, Mr. Hudson, and Mr. Matthey, having been nominated by the President, were elected by ballot Auditors of the Treasurer’s Accounts on the part of the Society. The Presents received were laid on the table and thanks ordered for them. The following Papers were read :— I. “On the Essential Properties and Chemical Character of Beryllium (Glucinum).” By L. F. Nison and OTTo PETTERSSON. Communicated by WARREN DE La RUE, D.C.L., F.R.S. Received June 21, 1880. In this paper we wish to call attention to some experimental facts which may give a clue to the real nature of beryllium, an element which since the beginning of this century has been the enigma of inorganic chemistry. The oxide of beryllium was discovered in 1795 by Vauquelin. It was considered a monoxide, BeO, until 1815, when Berzelius* ranged it, principally on account of its basic sulphates, among the sesqui- oxides. The weighty reasons for this arrangement, never since refuted, which Berzelius added later in the fifth edition of his ‘‘ Lehrbuch d. Chemie,” p. 1225, are too well known to be recorded here. In 1842 Awdéeff+ analysed the double sulphates and fluorides of beryllium, which showed qualities not agreeing entirely with the analo- gous compounds of aluminium, iron, chromium, &c. As the formula of these compounds could be written KO,SO,+Be0,S0s,, KE! 4 BeEl, this was considered by the chemists of that time to support strongly the old theory. Still the classification of Berzelius prevailed and was confirmed by H. Rose,t who showed the correspondence of the mole- * “Schweigg. Journ. f. Ch. u. Ph.,” xv, p. 296. i) ogo eam)? ivi, 1p LOL t “ Pogg. Ann.,” Ixxiv, p. 429. YOL. XXXI. E 38 L. F. Nilson and Otto Pettersson. [Nov. 18, cular volumes of Be,O, with AI,O3, and also by Ebelmen,* who ob- tained the oxide of beryllium in crystals isomorphous with A1,O,. Subsequently an elaborate work, ‘‘ De Glucium et de ses Composées,”’ 1855, by Debray,+ once more caused a change in the prevalent opinion. Debray regarded beryllia as an isolated member of the series occupy- ing a position intermediate between the monoxides and the sesqui- oxides, and showing marked analogies with both groups, but not intimately connected with either of them by isomorphism. As the analyses of its compounds in most cases agreed better with the simple formula BeO, this was preferable to Be,Qs. Klatzo,t in 1868, endeavoured to decide this matter finally by the assumption of a complete isomorphism between the sulphates of Be and Me, Co, Fe, Ni, and though Marignac,§ in 1873, proved that this pretended isomorphism did not exist, and was founded on a grave mistake, the opinion that beryllia was a monoxide was at this time universally accepted by chemists. Theoretically this opinion was founded on the “ periodic law” of Mendeléeff.|| The classification of beryllium at the head of the second group among the diatomic elements is a leading point in the theory of Mendeléeff. If the composition of beryllia was Be,O,, and the atomic weight of beryllium=18'8, instead of 9:2, the place of Be=9°2 in the system would be vacant, and the order of the series partialiy reversed, the “atomic analogies”? would be overthrown, and, still worse, beryllium =13°8 would find no place at all in the system, except in the fifth group among the five-atomic elements, to which it certainly does not belong. The final decisive proof still wanting to confirm the ideas of Mendeléeff’s was furnished, 1877, by Reynolds,4{ who found the specific heat of metallic beryllium=0°642, which (Be=9'2) makes the atomic heat=5°9, in accordance with the law of Dulong and Petit. About a year before the publication of Mr. Reynolds, we had suc- ceeded, by means of a new method, in isolating metallic beryllium from its chloride. We employed** a massive crucible of wrought iron, hermetically closed by a screw-plug, wherein equivalent quantities of berylium chloride and metallic sodium were heated to redness. Metallic beryllium was thus obtained, partly fused into globules, partly forming aggregations of little prismatic crystals, which in brightness ann. (d. Choa, Pharm.7 Isc, palate + ‘“ Ann. de Chimie et de Phys.,’’ [3], xliv, p. 5. ft “ Ueber die Constitution der Beryllerde.”” Dorpat, 1868. “ Journ. f. Prakt. Ch.,”’ cvi, p. 227. § “Ann. de Chim. et de Phys.,” [4], xxx, p. 45. || “Ann. d. Ch. u. Pharm., Suppl.,” viii, p. 151 (1871). @ “Phil. Mag.,” [5], iii, p. 38. ** For the details of the experiment see “ Darstellung und Valenz des Beryl- liums,”’ “ Pogg. Ann.,” [2], iv, p. 554 (1878). 1880. | On the Essential Properties, &¢., of Beryllium. 39. and colour resembled needles of polished steel. The metal was, as might be expected, not absolutely pure. The analysis was somewhat difficult, the mean result of a number of accordant determinations being :— Be (metallic). occ. ss os 86:94 per cent. Bes On paras cir. elton - 9°99 ss epee. fb A eects ne see 2°08 a LOR rawet data atosbers sands AMS 0°99 55 100:00 We next determined its specific heat by the method of Bunsen (ice- calorimeter). We here met with quite unexpected difficulties; but, having given up the original arrangement of the experiment described by Bunsen* as impracticable, we, by means of an arrangement similar to that recommended by Schulier and Wartha,+ obtained the following results :— f Specific heat of Be=0°4084 between 0° and 100°. Atomic heat of Be=5'64 [| Be=13°8]. These results, not in accordance either with those recently obtained by Mr. Reynolds or the periodic law of Mendeléeff, were not accepted without hesitation by chemists. Notwithstanding that, the editor of the new edition of Gmelin’s ‘‘ Handbuch d. Chemie,” Professor Kraut, altered the formule of beryllia and its compounds in the part of the great encyclopedia of chemistry then passing through the press, several other chemists publicly or privately commented on our work, and urged us to pursue our inquiries further. Among the objections thus made we deem the following most worthy of discussion. Mr. Lothar Meyer § hints that the equivalent of beryllium may be wrong, and suggests a revision of that number. If it should be found lower than 4:0, instead of higher, beryllium may still be considered a three-atomic element, without upsetting the periodic law. In that case it would only be necessary to interpose a new group of metals between the trivalent and quadrivalent elements. We had no reason to doubt the accuracy of the old number (=4°6), which we had found and verified by many analyses, but we redeemed our promise to Mr. Lothar Meyer,|| and undertook the following determinations of the atomic weight of beryllium. In order to determine this value with the utmost accuracy, we thought it safest to choose the simplest possible method, viz., the eee hore.Anny.,”” cxli, p. I. Pe Pore, Ann.” [2)|, 11, p. 359. +t Obs.—Allowance is made for the impurities of the metal. The specific heat of Be,03 was found =0'2471 between 0O—100° C. § “Ber. d. Deutsch. Chem. Gesellsch.,” xi, p. 576. || Ibid., p. 906. 40 L. F. Nilson and Otto Pettersson. | Nov. 18, analysis of its sulphate. Originally we also thought of analysing the chloride by titration with silver nitrate, but having found that sublimed beryllium chloride could not be obtained entirely pure, on account of its corrosive action on glass, we gave up the idea. Sulphate of beryllium is undoubtedly a neutral salt, and is easily obtained in beautiful crystals, which do not change in the air; but at 100—110° C. it loses half of its water, at 250° it becomes anhydrous, and after heating to light redness pure beryllia remains. Still thereisa difficulty in the analysis; for anhydrous sulphate and pure beryllia, as obtained by calcination, are both very hygroscopic substances. We therefore chose the hydrated sulphate, which could be weighed with the greatest accuracy, as the most fitting substance to start with ; this salt allowing pulverisation and pressure* without losing a trace of its constituent water. The sulphate was prepared by heating to dryness an aqueous solution of sublimed chloride with an excess of pure sul- phuric acid. By repeated crystallisation the sulphate could easily be purified from a slight trace of calcium sulphate, originating from the action of the gaseous chloride on the glass tubes. The analyses I, II, refer to beryllium sulphate obtained in this manner; for III, IV, the chloride was precipitated with ammonia and the hydrate treated with sulphuric acid. The sulphate was repeatedly crystallised. The difficulty in the analysis is the weighing of the calcined beryllia. For this purpose the crucible, still red hot, was placed in an exsiccator filled with anhydrous phosphoric acid, and after cooling placed immediately on the scale pan of a Bunge’s balance, the equilibrium being beforehand approximately established. In this manner the whole operation required only a few seconds. By spectroscopical test Professor Thalén has found the beryllia used for these determinations to be absolutely pure. The hydrated beryllium sulphate has given in the determinations, thus executed, the following values :— | Weighed | Loss of water | Loss of water Basie I he wivarleeet of feepnee, at 100° C. | and SO3. ae | beryllium. | Experi-| CE it a ry eater or. ees x per 4 per : per Pe O= pee es Bt cent. | 8° | cent. 8. | cent. ie (SS I | 38014 | 0°7696 |20-245 | 3-2627 | 85-829 | 0°5387 | 14-171 | 4556 | 4-544 Il | 26092 | 0°5282 | 20-244 | 2°2395 | 85°831 | 0°3697 | 14169 | 4552 4542 me A3072 |) — — | 36973 | 85-840 | 0:6099 | 14°160 | 4°545 | 4533 | IV |3:0091| — | — | 25825 | 85-824 | 0-4266 | 14176 | 4°557 | 4550 |Mean| — | — — 95:80 | — | 14169 | 4552 | 4542 * It was pressed between sheets of fine, porous, bibulous paper, the surface of which had been previously smoothed by heavy pressure. 1880.] On the Essential Properties, §¢., of Beryllium. Al The equivalent of beryllium has hitherto been determined by— ISCEZElUS|,. 2.252 as <4 = ARO crave) ae (analysis of the sulphate). , Ad Wet e st 5 25 7 me ge zs ere Bey a (analysis of the chloride). WMiccren......°. 2... Pea a ye ae (analysis of the sulphate). MATA Gb eins vee ase NE: 1 Re es 4 a Welorays i. wees es = 461—471 (analysis of the oxalate). Nilson and Pettersson = 4°552..... (analysis of the sulphate). All these numbers are higher than 40, and consequently the atomic weight of beryllium, if trivalent, must be 13°65, consequently higher than that of carbon. The before-mentioned supposition is conse- quently proved to be unfounded. Mr. Lothar Meyer further observes that the atomic heat of the oxygen in beryllia, if a sesquioxide, would be less than in any other oxide known. In the next paper we give the whole series of our determinations of the molecular heats of the rare earths and their sulphates. From this survey, which shows that beryllia, with regard to heat and volume, occupies its proper place at the head of the sesquioxides, we here only extract a few determinations.* If ¢ signifies the specific heat,— Atom. heat of oxygen. In Be,O, c= 75°32 . 0:2471=18°61 Be, c= 27°32 . 0°4246=11-60 COV=3. 234 ,, Al,O; e=102°8 . 0°1825=18:78 Al, c= 548. 0:2143=11:74 (048. 2°35 », Se,0, c=1360 . 0:1530=20-81 Se, c= 88:0. 0:1454=12-80+ Ose Oe * Our determinations refer to pure oxides obtained by chemical operations. They are also strictly corresponding and comparable. Other determinations with native alumina (sapphire), made by different methods (Regnault, Neumann), gave a higher number. Determinations by means of the ice-calorimeter always give smaller results, because the standard measure for the heat developed is greater (1 calory = mean of the specific heat of water between 0O—100° C.). + The atomic heat of scandium is supposed to be =6'4, according to the law of Dulong and Petit. A2 L. F. Nilson and Otto Pettersson. [Nov. 18, Atom. heat of oxygen. In Ga,O, c= 184. 0:1062=19°54 Ga, c= 136. 0-0802=10-91 S103-—5-6 ice , In,0, c=274:8 . 0:0807=2217 In, c=226'8. 0:0570=12'92 9°25=3. 3:08 According to the determinations made by us under identical con- ditions, and therefore strictly comparable, the atomic heat of oxygen in beryllia= Be,Os is the same as that in alumina; this, however, can by no means be considered as exceptional. Alumina and berylla are the leading members of a group of sesquioxides, wherein the atomic heat and (as will be seen from the following paper) the atomic volume of oxygen increases with increasing values of the atomic weights of the metals. We will now refer to another objection raised to our former re- searches. Mr. Brauner* admits the specific heat of beryllium to be 04084 between 0—100°, but supposes that it may rapidly increase with the temperature in the same way as does the specific heat of C and Bo. If this were the case, he thinks beryllia could be BeO, the atomic heat of beryllium=3°76 between 0—100°, and normal=6'4 first at a much higher temperature. In our detailed paper, we have tried to meet such an objection, by pointing out that no metallic element is as yet known, the atomic heat of which does not agree with the law of Dulong and Petit. However, in order to remove any doubt in this respect, we have determined the specific heat of beryllium at different temperatures lying between 0—300° C. We siitted the metal used in our former determinations through a gauze of platinum, the holes of which were 0°25 sq. millim. For the following experiments we used only that part which did not pass through the gauze, on the supposition that this, consisting of globules and larger crystals, was the purer metal. The analysis confirmed this opinion, for the composition was found to be— Beryllinm .;...3: sane eee 94°41 Berylliag it! ee eer 489 lrons? ) oe eee ee 0:70 100°00 The following table gives only the results, not the details of our * “ Ber, d. Deutsch. Chem. Gesellsch.,” xi, 1872. 1880.] On the Essential Properties, &c., of Beryllium. 43 determinations ;* the values are referred to pure beryllinm, making allowance for the impurities of beryllia and iron :— Temperature. Specific heat. Atomic heat. ° fo} — 46°30 C 0°3959 O— 46°30 0°3950 FAG Heating in the vapour O— 46-30 0:3980 2 of CS,. O0— 46°50 0°4005 0—100°18 0°4.250 \ 549 Heating in the vapour O— 99:97 0°4242 of water. 0—214'0 0°4:749 6-48 Heating in the vapour * 0—214:0 0°4751 } | of nitrobenzol. 0—299°5 075084 6-90 J Heating in the vapour 0—299°5 0°5066 \ {| of diphenylamine. Thus the specific and atomic heat of beryllium increase with the temperature, but a comparison with the same numbers for iron between 0—300° C. shows that such an increase of these values is not unusual. 0=1007; 0—300°. Authority. | Specific | Atomic | Specific | Atomic heat. heat. heat. heat. HOM c--evs vs 071124. 6°29 0°1266 7°09 Béde. Beryllium... | 0°4246 5°79 0°5060 6°90 Nilson and Pettersson. Between 0—100° C., the atomic heat of beryllium is equal to that of aluminium=5'87, and gallium=5'59, at 214° C. it is normal=6°48, and at 300° C. it has attained the same value as iron at the same temperature. Beryllium can thus certainly not be compared with the diamond in this respect, the specific heat of which, according to the researches of Weber, being many times higher at 0—300° C. than at 0—100° C.+ Every doubt as to the real atomic weight of beryllium must be * We have also been obliged to determine the increase of the specific heat of be- ryllia and platinum by higher temperatures in the same way as that of beryllium itself, the metal for the experiments being enclosed in little capsules of platinum foil, hermetically soldered with chemically pure gold. Glass tubes cannot be em- ployed at higher temperatures than 100° for two reasons: Ist, the glass would crack when suddenly cooled to 0°; and 2nd, its specific heat increases very rapidly. + “ Ber. d. Deutsch. Chem. Gesellsch.,”’ v, 303. 44 L. F. Nilson and Otto Pettersson. [Nov. 18, removed by the results above mentioned. Fixed at 13°65, according to our determinations, the value of its atomic heat becomes perfectly harmonious with the law of Dulong and Petit. We will, in conclusion, say a few words upon a paper wherein the results of our former researches have been criticised. in the ‘“‘ Pro- ceedings of the Royal Society,” 1879, Mr. Carnelley applies a new method of calculating the fusion points of halogen compounds, and applying it to those of beryllium, argues in the following manner :— Beryllium must be either a dyad or a triad, and must belong either to the second or to the third group of Mendeléeff’s series ; if a dyad or Be=9'2, its chloride, BeCl,, can be calculated to fuse at+547— + 600° C, which is confirmed by experiment; if a triad or Be=13°8s the chloride, BeCl, or Be,Cl,, ought to fuse about 500 degrees lower, i.e., at-+50°—+100° C., which it obviously does not; ergo, beryllium is a dyad, and Be=9-2. We presume that Mr. Carnelley’s knowledge of the physical pro- perties of the triads is, like our own, very limited. With the exception of aluminium, we really know little or nothing of the melting or boiling points of chlorides, bromides, and iodides belong- ing to this group, and we think analogies taken only from one member, aluminium, to be too narrow a base for a calculation whichis meant to apply tothe whole group. ‘There may be chlorides, bromides, and iodides which do not behave like Al,Cl,, in regard to boiling and fusion points. We will, in the following paper, give reasons for our opinion that beryllium and aluminium are each leading members of two different groups of trivalent metals. The nearest relatives of beryllium among these are neither calcium and magnesium, with which it has, in fact, little or nothing in common, nor aluminium, with which it has very much more in common, but rather the rare elements, scandium, yttrium, erbium, and ytterbium. We believe that Mr. Carnelley ought to try his calculation on the halogen compounds of the rare elements before asserting “ that Nilson’s and Pettersson’s determination of the specific heat of beryllium must be incorrect.” If the properties of the halogen com- pounds of these elements should be found to agree with the calcula- tion, then we confess that the matter becomes somewhat uncertain, for then one will have to choose between the law of Dulong and Petit and that of Carnelley.* Our above-mentioned experimental researches, confirmed still more by the experiments, which will be quoted in a second paper, lead us to the conclusion that the real atomic weight of berylhum is=13°65. But with this value the periodic law cannot admit this element among the metals nearest related, and this fact obviously militates against its * “ Ber, d. Deutsch. Chem. Gesellsch.,” v, 303. 1880.] On the Essential Properties, S¢., of Beryllium. 45 general applicability. Before concluding this memoir, we will just point out that this is not an isolated case of its kind. For the element which should take its place between Sbh=122 and [=127, the periodic law requires an atomic weight=125; with regard to its general properties tellurium is quite admissible in this place, but its atomic weight=128 is tod high. Although this number was the result of the determina- tions of Berzelius and v. Hauer, this want of accordance with the periodic law induced Willis* to make a new determination, but he only confirmed the former results. Thus neither tellurium nor beryl- lum can be fitted into Mendeléeff’s system. And further, after Councler’st discovery of the boroxychloride, BoOCl,, boron may be considered as five-atomic, but it certainly cannot be placed among elements of that valence; and when ounce the chemistry of the rare earth-metals shall be made clear, where can be placed all these elements, the number of which has already become very great and doubtless will be still augmented? Already erbium and ytterbium, with the now fixed atomic weights of 166{ and 173,§ for the pure metals (the earths=Hr,O, and Yb,0;), can scarcely be ranged in Mendeléeff’s system in places indicated by their relation to the other earth-metals or by their “ atomic analogies.” In consequence of what has been indicated here, the periodic law in its present condition cannot be said to be quite an adequate expression for our knowledge of the elements; this theory, however, having given the most striking proofs that the truth in many respects has been found (as for example: the new formule for the rare earths =R,O0, instead of RO, and the discovery of gallium and scandium, the existence of which the law has foreseen in the elements eka- aluminium and eka-boron), we may expect that the periodic law may be so modified and developed that it can embrace and explain every fact, stated by experiment. * “ Viebig’s Ann. d. Ch.,” ccii, p. 242. + “ Ber. d. Deutsch. Chem. Gesellsch.,” xi, p. 1108. ~ According to Cleve. § According to Nilson. 46 L. F. Nilson and Otto Pettersson. [Nov. 18, II. “On the Molecular Heat and Volume of the Rare Earths and thei Sulphates.” By L. F. Nmson and OTTo PETTERSSON. Communicated by WaARREN De LA JET, D.C.L., F.R.S. Received June 21, 1880. At the request of the Royal Academy of Sciences at Stockholm, we some years ago undertook an extended research into the physical pro- perties of the rare earth-metals and their compounds. Having per- formed the laborious task of separating and purifying their oxides, we are now able to publish our first series of determinations concerning their principal properties, which chemically are of the greatest im- portance, viz., molecular heat and molecular volume. The rare earths, with a few exceptions (CeO,, ThO,, ZrO,), belong co a group of sesquioxides. In order to obtain a larger number for comparison, we have extended our research not only to the rare earths, but also to some other nearly related compounds, the molecular heat and volume of which were hitherto unknown. As to these values, previously known for some other oxides, Al,O3, Fe,03, Cr,O3, according to Regnault, Kopp, and others, we have already observed in our pre- ceding paper “ On the Essential Properties and Chemical Character of Beryllium,” that only such determinations are strictly comparable which are made by the same method, under the same circumstances, and referred to the same unit of measure. The specific densities and molecular volumes, which are given in the following tables, are obtained by means of a method, specially adapted to prevent the errors arising from adhesion of air to pulve- rulent substances.* The densities taken by this method will there- fore generally be found a little higher and the molecular volumes a little lower than the numbers usually given by others. The specific heats of the different compounds are determined with Bunsen’s ice-calorimeter, by means of the same process which we have more fully described in our detailed memoir on beryllium.} All the numbers given are the means of at least two determinations, which agree perfectly, the experiments being made under the most favourable circumstances. As to the values obtained, we beg to observe that the specific and molecular heat will be found a little smaller by the ice- melting method than by other methods, on account of the different unit of comparison. The molecular weight of the different oxides was determined by a special analysis or synthesis of the sulphates, and the very same chemi- * For the details, see Otto Pettersson, “‘ Molecularvolumina einiger Reihen von isomorphen Salzen,” in “ Noy. Act. reg. Soc. Scient. Ups.,” ser. ui. Upsala, 18738. + “ Pogg. Ann.,” [2], iv, p. 554. 1880. | On the Rare Earths and their Sulphates. 47 cally pure substances were employed both for the thermic, volumetric, and magnetic experiments. The results only and not the details of these experiments are given in the tables. Oxides. ole Specific | Specific Moles) Miele: Compounds. Formula. cular ge P cular cular E weight. | heat. weight. heat. | volume. Beryllium oxide ..| Be,O3.... 753 3°016 | 0:2471 18°61 24-97 Aluminium oxide..} Al,O3....| 102°8 3°990 01827 | 18°78 25°76 Sapphire cryst.....} AlpO3....| 102°8 3°990 ONS879 peg :32 25°76 Al; se : Chrysoberyl cryst.. Be, \ Oe a9 3°734: 0°2004 | 19°22 25°69 Scandium oxide*..| Sc,03....| 136°0 3864 0'1530 20°81 35°19 Gallium oxidet ...| Ga,O3 ...| 1840 — 0°1060 19°50 — Wren oxide ....| YoO, ....| 227°0 5046 0°1026 23°29 44°99 Indium oxide..... IDO soc | ARS 7179 0:0807 | 22°17 38°28 Erbium oxidet....| Hr2O3 .. .| 380°0 8°640 0:0650 24-70 43°98 Ytterbium oxide ..| Yb.O,.. .| 3940 9175 00646 | 25°45 42°94, Lanthanum oxide .| La,O03....] 326°0 6°480 00749 | 24°42 50°31 Didymium oxide .. Di,O3....}| 341°0 6'°950 0°0810 27°62 49:07 Zirconium oxide...| ZrO, ....| 122°0 5°850 01076 13°13 20°86 Cerium bioxide .. .| CeO,..../ 171°5 6°739 0-0877 15:04 25°45 Thorium oxide....| ThO,....| 2640 9°861 0°0548 14°47 26°77 Hitherto it was supposed to be a general rule, that the atomic heat of oxygen in any oxide was not less than 3’0 or greater than 5°1. The numbers above given compel us, however, to assign a still lower value to the atomic heat of oxygen in alumina and beryllia, viz., 2°34.§ Into these oxides it enters with a minimum capacity of heat and volume. From these earths upwards the molecular heat and volume of the ses- quioxides gradually increase with increasing molecular weights. The following table shows that the molecular heat (1) of Hr,O,, Yb,O, La,Oz, and Di,O, nearly agrees with those for other sesqui- oxides, determined by Regnault; (2) that of Be,O3, approaches to the same for alumina; and (3) that of ZrO,, CeOQ,, and ThO, is as high as the values for SnO,, TiO,, and zircon, determined by the same author, and for MnO, according to Kopp. The validity of Neumann’s law receives hereby a new confirmation. * According to Nilson, + For the oxide employed we are under obligation to M. Lecoq de Boisbaudran, who placed 0:138 grm. gallium at our disposal. { Professor Cleve has kindly placed at our disposal the purest erbia he has been able to obtain. § See the preceding paper, page 41. 48 L. F. Nilson and Otto Pettersson. [ Nov. 18, | Molecular | Specific | Molecular : Formula. ceieTh, eae. heel Authority. BOR ORs eieicietiis 69°8 0°2374 16°57 Regnault Cr Oar sta sas « 15274 0°1796 27°37 + HesOM ens as dl60:0 0°1681 26:90 i WO 82569. |. 198-0 0:1279 25°32 © SO ta 02) | 2920 0:0901 26°31 - [oii OR gragide Sc 468-0 00605 28°31 A DO slays civ ieee: 82°0 0°1703 13°97 9 Si, } ; : Zn, FOrrrseee| 908 0:1456 13°22 t SiN Os Gaceed age 150°0 0:0933 14:00 ys MbNOE saa cd oe 87:0 0°1590 13°83 H. Kopp Anhydrous Sulphates. Mole- Se acificl Saeeia Mole- | Mole- Compounds. Formula.| cular |°P°° eee | cular | cular : weight.| heat. weight. heat. | volume. Beryllium sulphate...| Be,88O, | 315°3 | 2-443 | 0:1978 | 62°37 | 129-07 Aluminium sulphate..} Al,38SO, | 342°8 2°710 | 0°1855 | 63°59 | 126°50 Scandium sulphate...| Se3S8O, | 3760 2°579 | 0°1639 | 62°42 | 145°80 Chromium sulphate ..| Cr,38SO, | 392°4 3°012 | 01718 | 67-41 | 180°27 Ferric sulphate ...... Fe2:380, | 400°0 3°097 | 01656 | 66°24 | 129°16 Gallium sulphate.....| Ga 3804 | 424-0 — 0'1460 | 61°90 = Yttrium sulphate ....| Y.388O, | 467:0 2°612 | 01819 | 61:60 | 178°80 Indium sulphate.....| Inj38S8O,4 | 5148 3°438 | 0:°1290 | 66°41 | 149-77 Lanthanum sulphate..| La,38O, | 566-0 3°600 | 0°1182 | 66°90 | 157:22 Cerium sulphate ..... Ce,3880, | 567:0 3°912 | 01168 | 66°23 | 144-94 Didymium sulphate ..| Di,3SO, | 581-0 3°735 | 01187 | 68°96 | 155°55 Erbium sulphate .....| Er,3SO, | 620°0 3°678 | 071040 | 64°48 | 168°57 Ytterbium sulphate...| Yb.8SO3] 634°:0 3°793 | 0°1039 | 65°87 | 167°15 Thorium sulphate ....| Th,280,| 424-0 = “| 009721). 4-2 The molecular heat of the anhydrous sulphates of the sesquioxides varies only within very narrow limits; 61°60—68'96 for yttrium and The values for the salts of chromium, iron, in- dium, lanthanum, cerium, and didymium are nearly identical; whilst even the values of the remainder approach each other very nearly. As the following hydrated sulphates are decomposed when heated didymium sulphate. to 100°, their capacity of heat was determined between 0° and 46° in the vapour of boiling CS, ; the berylliuin sulphate not bearing even that temperature without losing water, its molecular heat could not be ascertained. 1880. | On the Rare Earths and their Sulphates. 49 Hydrated Sulphates. Molecular| Specific | Specific | Molecular | Molecular Compounds. Boron, weight. | weight. heat. heat. volume. Beryllium sulphate. ......| Be,38S0,.12H,O| 531°3 1°713 — — 310°17 Yttrium sulphate.......... Y,3S0,.8H,0...| 611°:0 2 °540 0 °2257 137 °91 240 °55 Lanthanum sulphate ....| La,38S0,.9H,0.) 728°0 2 °853 0 °2083 151 °64 255 °17 Cerium sulphate .......... 1€,890,.5H,0. | 657-0 3 °220 0°1999 131 °33 204 °04 Didymium sulphate ......J Di,880,.8H,O.| 725°0 2°878 0°1948 -} 141°23 251°91 Erbium sulphate* ......... Er,3580,.8H.0. | 764°0 3°180 0°1808 138°13 240 °25 Ytterbium sulphatef...... Yb,3S0,.8H,0.| 778°0 3 '286 0°1788 139°11 236°79 On subtracting the values obtained for the anhydrous salts from the same numbers of the hydrated sulphates, we obtain a remainder expressing the molecular heat and volume of the water in combination. Thus the following values are obtained :— Water in Molecular | Molecular Compounds. aay: Pp combination. heat. volume. Ytterbium sulphate...| 8H,O...... 9°15 8°70 Erbium sulphate.....| 8H.O...... 9°21 8°96 Yttrium sulphate... .. SHE Ohne ter 9°54. Che Didymium sulphate ..| 8H,O...... 9:03 12°04 Lanthanum sulphate .| 9H,O...... 9°42 10°88 Cerium sulphate ..... DELON 1) | La.02 11°82 The molecular heat and volume of free water being =18, it will be seen that by entering into combination with the sulphates of the rare earth-metals, its heat and volume are reduced in an extraordinary degree. In fact, the molecular heat and volume of water in these salts descends to a minimum value hitherto unknown. Comparing the values given above, we readily find that in those groups of compounds intimately connected by isomorphism, the molecular heat of the compounds increases and the molecular volume decreases with increasing molecular weight of the compound or atomic weight of the element. This will be shown by the following table, in which the different isomorphous compounds, partly of yttrium, erbium, and ytterbium, partly of lanthanum and didymium, are brought into comparison :— * According to Cleve. + According to Nilson. 50 On the Rare Earths and their Sulphates. [Novy. 18, 5 Anhydrous Hydrated | Oxides. sulphates. sulphates. Elements. Atomic weight.| Mole- | Mole- | Mole- | Mole- | Mole- | Mole- cular cular cular cular cular cular heat. |volume.| heat. | volume.| heat. | volume. Wittriame .. 5... ss 89°5 23°29 44,99 61:60 178°80 137°91 240°55 Erbium ........| 166°0 | 2470 | 43°98 | 64°48 | 168°57 | 188138 | 240-25 Ytterbium ......| 173°0 | 25°45 | 42:94 | 65°87 | 167:15 | 189°11 | 236-79 Lanthanum...... 139:0 | 24°42 | 50°31 | 66°90 | 157:22 — = Didymium......| 1465 | 27:62 | 49:07 | 68°96 | 155°55 = — | Hspecially with regard to berylla, and the question of its real composition, the values given above are of the greatest importance. In respect of this we observe that: 1st, the atomic heat of oxygen in beryllia is identical with that in alumina and nearly identical with the same value in other closely related oxides, if beryllia =Be,O, (see our preceding paper, p. 42); 2nd, under the same supposition the molecular heat and volume of beryllia and alumina are nearly identical, whether the latter earth be examined in the state of crystallised sapphire or of an amorphous powder, and, further, 1f we consider chrysoberyl not as an aluminate, but as aE } O,, this mineral has es yielded identical values; 3rd, the molecular heat and value of beryl- lum sulphate, compared with the same values for the other nearly allied sulphates of aluminium, scandium, gallium, and yttrium, support the formula Be,O, which we have given. Taking into consideration the above-mentioned circumstances, and those related in our former papers, with the fact that the atomic heat and volume of metallic beryllium, as well as the molecular heat and volume of beryllia and its sulphate, would assume values quite ex- ceptional, if the formula for the oxide were BeO, we think, there-— fore, the question of the valence of beryllium may be considered as finally decided. In fact, there is no physical property of beryllium, beryllia, or its sulphates, which does not testify to our view being the correct one, and from a chemical point of view the same holds good. It is, we think, unnecessary to take up space here with a repetition of the various reasons which support this conclusion. We refer, therefore, to our detailed paper on beryllium, above quoted, and only mention here that this metal belongs on account of its sulphate, 3K,80,+ Be,3SO,, to the series of the gadolinite and cerite metals, this salt having a composition, typical for all the members of this series (Be, Sc, Y, La, Ce, Di, Tr, Ya, Ye, v, Hr, Tm, Yb).- The series of these elements, the 1880. ] On the Absorption Spectra of Cobalt Sales. 51 leading member of which beryllium unquestionably is, stands certainly in the nearest proximity with an other series, that of aluminium (Al,, Gay, Tn, Cro, Mny, Fe,), but this nevertheless decidedly differs from the former by an other typical double sulphate, K,S0,+R,380,+ 24H,0. or alum. The fact, which has been alleged as a proof of the bivalence of beryllium, namely, that the chloride fuses and sublimes at a higher temperature than aluminium chloride is of no importance, for it will be found that amongst the members of the former series, with its difficultly fusible and volatilisable chlorides, many analogies exist for beryllium, not only in this but in many other respects. Lastly, we subjoin a table showing the magnetic properties of the rare earths. Mr. Knut Angstrém kindly undertook this research, employing a powerful electromagnet of Ruhmkorff, between the poles of which the oxides showed the following properties :— Magnetie. Diamagnetic. CeO POU Ae Be, Os. Ae, AO) EU Ah anes Al,Os Y,05 Se ee Sc,O0; ? Di,O03 mia setatl e ale In,O; BRO) eid). La,Oz Yb,0; eocee pe ee Tr) Sahn At A a ear eitatte aie rO, CoO Sr Se ThO, if. “On the Absorption Spectra of Cobalt Salts.” By W. J. RUSSELL, Ph.D., F.R.S., Treas. C.S., Lecturer on Chemistry at the Medical School, St. Bartholomew’s Hospital. Re- ceived August 4, 1880. (Abstract. ) The following investigation was commenced with Mr. Lockyer, and although he has been unable to continue the work, the author is indebted to him for much aid and many suggestions. The cobalt salt first examined was the anhydrous chloride. In order to establish clearly its absorption spectrum, different samples of this salt were made by various processes. All, however, gave the same spec- trum. The bromide of cobalt yields a similar spectrum, but its posi- tion is different, it is nearer to the red. 52 Dr. W. J. Russell. [Nov. 18, On fusing cobalt chloride with potassic chloride, a greenish-blue mass is formed, which gives a spectrum entirely different from that of the chloride when alone. Judging from the fusing-point of the mix- ture being lower than that of the components, and the cobalt salt not decomposing in this mixture on fusion in contact with air, 1t seemed natural to suppose that a new compound had been formed, and that it gave rise to the new spectrum. Further experiment showed, how- ever, that this is not the case for other solid chlorides, such as of sodium and zinc give with cobalt chloride the same spectrum; and liquids in which the cobalt chloride easily dissolves, such as ordinary or amylic alcohol, the saline ethers, glycerine, and hydrochloric acid, also give this same spectrum ; in fact, this spectrum is produced whenever cobalt chloride dissolves freely in any menstruum without definitely combining with it. A careful set of experiments were made in the case of the solid chlorides, to exclude the presence of water, for it was possible that the spectrum in all the above cases might be due to a trace of water, which, by its combining with the cobalt chloride, formed in every instance the spectrum-giving body. The bromide and iodide of cobalt, when fused with potassium bromide and potassium iodide respectively, give results corresponding to those of the chloride, but the bands in the spectrum of the bromide, and still more so those of the iodide, are nearer to the red than the corresponding bands of the chloride. The action of heat and of water on the bodies producing these spectra is discussed, and it is pointed out how the definite compound with zinc was indicated by the spectrum. The action of liquids which easily dissolve the cobalt chloride is next described, and as all give the same spectrum, and this spectrum is identical with that obtained with the fused chlorides, the conclusion drawn is, as before stated, that this spectrum must be that of the cobalt chloride, only, owing to solution, it is in a mole- cular state, different from that obtained on fusing this salt alone. This spectrum, when obtained in the hydrochloric acid solution, is remarkable for its persistence under varying circumstances, and for its being a reaction of great delicacy. Hydrochloric acid as a solvent for the cobalt chloride differs in one respect from all the other solvents which have as yet been examined, namely, that, whether much or little cobalt be dissolved in it, the spec- trum is the same; whereas with dry alcohol, for instance, a saturated, or nearly saturated, solution gives the spectrum above mentioned, but a dilute solution, one containing about 20 grms. of the chloride in 100 cub. centims. of alcohol, gives a spectrum somewhat different: a new band appears and others which were present fade out: if this dilution be carried on still further, so that only about 0-008 grm. of the chloride be present in 100 cub. centims. of alcohol, an entirely different spectrum is obtained, but on carrying the dilution beyond this no 1880.] On the Absorption Spectra of Cobalt Salts. 53 further change takes place. With other liquids which dissolve the cobalt salt freely, a similar series of changes occur, but if liquids in which the chloride is much less soluble be used, then according to their solvent power only the first (or most dilute stage), or the first and second stage, is obtainable; for instance, if dry ether is used as the solvent, it yields only a spectrum corresponding to the first stage. With anhydrous acetic acid, in which the cobalt chloride is more freely soluble, hoth the first and second stage are obtainable. If the dry chloride in fine powder be shaken up with a liquid in which it is inso- luble, such as carbon tetrachloride, then only a svectrum similar to that of the fused chloride is visible. The anhydrous cobalt chloride dissolved in water gives a pink solu- tion. This solution, when it contains as little as 0°l grm., or as much as 25 grms., of the salt in 100 cub. centims. of water, gives only a wide absorption-band, shading off on both sides, and whether a short column of the strong solution or a correspondingly long column of the dilute solution be examined, identical spectra are obtained, so that within these limits the same compound appears to exist in the solution. If, however, the solution approaches saturation (100 cub. centims. of water can dissolve at 16° 32 germs. of the cobalt chloride), then another spectrum is visible, and this is again the spectrum of the dissolved chloride: the same spectrum as is obtained either by dissolving cobalt chloride in fused potassium chloride, or in alcohol, or in hydrochloric acid, thus apparently the anhydrous chloride exists in an aqueous solution. The action of heat, and the action of bodies capable of combining with water, in aqueous solutions of cobalt chloride, are identical, both tending to destroy the broad absorption ‘band of the hydrate, aud to form the banded spectrum of the dissolved anhydrous chloride. The very characteristic spectrum of the oxide of cobalt is well known. ‘The precipitate obtained by the addition of potash or soda in excess to any cobaltous salt, shows well this spectrum. If ammonia be the pre- cipitant, a somewhat simpler spectrum is obtained. Vogel has already pointed out the similarity of the spectrum of a piece of cobalt glass and this oxide spectrum. The glass spectrum is apparently similar to the spectrum formed by the precipitate with potash and soda, probably then the extra band visible in these cases and not when ammonia is used, is due to a compound of the alkali and cobalt. The bearing of these spectra on Winkler’s supposed cobaltate of potash is then discussed. Further, it is shown that if the above precipitation of oxide be made in solutions in which the cobalt salt is in excess, or even if precipitated oxide be warmed or shaken up in the cold with a solution of cobalt chloride, a new compound is formed, an oxychloride which gives a different spectrum; its formation and its decomposition ‘by water is well traced in the varying spectra producible from it, and VOL. XXXL. E 54 Prof. W. C. Unwin. [Nov. 18, goes hand in hand with the chemical changes which occur. From the spectroscopic appearance it is argued that the blue precipitated oxide is not a hydrate, but that it does very readily undergo change as the mere alteration of colour which takes place shows. Aqueous solutions of the bromide and iodide of cobalt when acted on by aikalies undergo changes similar to those which the chloride undergoes, and, as in the former cases, the iodide spectrum is always nearer the red end of the spectrum than the corresponding bromide spectrum, and the bromide: than the chloride spectrum. The salts of the oxygen acids when in aqueous solution do not give sharp banded spectra as the haloid salts do, but only a large shading off absorption like the hydrate of the cobalt chloride. The other points discussed in detail are, first, the nature of the precipitate formed by the action of sodic or potassic carbonate on a cobaltous salt, and it is shown that the formation of the oxide always found in this precipitate is owing to an after decomposition, the pre- cipitate as first formed being entirely free from all oxide, and it gradually appearing after a short time. The other point is the action of heat on cobalt phosphate dissolved in fused microcosmic salt; when cold there appears somewhat indistinctly a banded spectrum of a phosphate, on heating this the spectrum disappears, and the spectrum of the oxide very distinctly takes it place; on cooling, the first spectrum returns, and this change may apparently be repeated any number of times. Drawings of all the different spectra are given in the full paper. IV. “On the Friction of Water against Solid Surfaces of Diffe- rent Degrees of Roughness.” By Professor W. C. UNWIN, M.I.C.E., Professor of Hydraulic Engineering at the Royal Indian Engineering College. Communicated by J. H. CoTTERILL, F.R.S., Professor of Applied Mechanics, Royal Naval College, Greenwich. Received August 31, 1880. (Abstract. ) These experiments relate to the friction of fluids when flowing against rough solid surfaces. It is well known that a board dragged through water suffers a resistance which, at speeds not very small, varies nearly as the square of the velocity. The fluid surrounding the board does not behave as a solid, but shearing and eddying motions are set up which give rise to. losses of energy distributed throughout the fluid mass. Most of the existing knowledge of fluid friction has been derived from the observation of the flow of water in pipes and canals. But im 1880. | On the Friction of Water, &c. a5 these cases, the motion of the fluid is complex, and the observations themselves are difficult. The principal direct experiments on fluid friction are those of Coulomb and of the late Mr. W. Froude. Cou- lomb’s experiments were made by oscillating a thin disk, suspended in the fluid by a wire, in its own plane. The gradual diminution of the range of the oscillations gave a measure of work lost in fluid friction, on the surface of the disk. Coulomb’s experiments were made at very low velocities, and, indeed, the method which he employed would be quite unsuitable for greater speeds of oscillation. The results at which he arrived were these :—(a.) The frictional resistance to the motion of the disk varied nearly as the velocity; (b.) The friction was nearly independent of the roughness of the surface; (c.) The friction was very much increased if the viscidity of the fluid was increased. Mr. Froude’s experiments were made in a very different way. He towed boards of lengths varying from 5 to 50 feet, in a still water canal, and measured by a spring dynamometer the resistance to the motion. His experiments were all made at speeds much higher than those employed by Coulomb. His results may be summarised thus :—(a.) The friction varies nearly as the square of the velocity of the board, the precise index of the speed to which the friction is pro- portional depending on the nature of the surface of the board; (b.) The frictional resistance per square foot of the surface of the board is greater for short than for long boards; (c.) The frictional resistance varies very greatly with the roughness of the surface of the board. The differences between the results of the experiments of Coulomb and Froude show that the phenomena of fluid friction at very low and at high speeds are essentially different. It appeared to the author that it would be useful to make some experiments at speeds similar to those in Mr. Froude’s experiments, but with an apparatus ona smaller scale, which would permit a greater variation of the conditions of the experiments. A series of disks, of 10 inches to 20 inches in diameter, were rotated in water by an engine, and the resistance to continuous rotation at different speeds was measured. Thus the experiments were virtually the same as Mr. Froude’s, but with a surface of infinite length substituted for surfaces of limited length. The roughness of the surface of the disk was varied, the smoothest disks being of turned and polished brass; the roughest having surfaces of sand and gravel cemented on to the metal disk. The disks were rotated in a cylindrical chamber, the size of which could be varied, so that the mass of water operated on, or the thickness of the layer of water in contact with the disk, could be modified at will, Further, the roughness of the surface of the chamber in which the disks were rotated was varied in the same way as the roughness of the disks themselves. ‘’o determine the effect of the viscidity of the liquid in altering the amount of friction, experiments were made with F2 56 Prof. W. C. Unwin. [Nov. 18, a solution of sugar in water. lastly, a series of experiments were made with water at different temperatures. Altogether several hundred observations of the resistance of the disks under different conditions were recorded. SSDS ( At Y : ANN NE Ns The figure shows a section of the apparatus employed. DD is the disk, the friction of which, when rotated in fiuid, is to be measured. This is keyed on a shaft, SS, which was driven from a hot-air engine by means of a catgut belt. The disk is placed in a cast-iron cistern, CC, 1880. ] On the Friction of Water, &e. 57 containing the fluid. Between the disk C and the outer cistern, how- ever, is the light cylindrical copper chamber, A.A, suspended by three fine wires from a crosshead, B. EE is a diaphragm, which could be moved up or down so as to alter the volume of water in the chamber in which the disk rotates. K is a brake for regulating the speed of the disk. W is the position of a counting arrangement for determining the speed of the disk. G is a scale-pan in which weights were placed. This was connected by a fine silk cord with an arc attached to the chamber AA. The weight in this scale-pan exactly measures the tendency of the chamber AA to rotate, in consequence of the rotation of the ftuid inside it. But since action and reaction are equal, the tendency of the chamber AA to rotate is, when the motion is uniform, exactly equal to the friction of the surface of the disk, DD. This method of measuring the friction of the disk, by measuring the re- action of the vessel containing it, was first used (so far as the author is aware) by Professor James Thomson. A short note on some experi- ments made in this way was communicated by him to the Royal Society in 1855, but the details of these experiments have never been published. The principle is the same as that employed by Mr. Froude, in his “Fluid Dynamometer.” The general results of the experi- ments made with the apparatus described above are in striking numerical agreement with Mr. Froude’s results, so far as the con-— ditions of the experiments are similar. But, from the small size of the apparatus, it has been possible to vary the conditions somewhat more than would be possible with the great canal of Mr. Froude. The results obtained may be summarised as follows :-— (1.) The resistance of disks of different diameters, but similar in other respects, varies as the fifth power of the diameter nearly, or, more exactly, as the 4°85th power. (2.) The resistance varies with the roughness of the surface of the disk to an extent quite as great as in the experiments of Mr. Froude. (3.) The friction increases in every case with the size of the chamber in which the disk is rotated. This result was certainly unexpected. Hven if the increase of resistance is due to the increase of the surface of the chamber, this result indicates another marked difference between the phenomena of fluid friction at high and at low speeds. At very low speeds the resistance would decrease considerably as the size of the chamber increased. (4.) Roughening the surface of the chamber in which the aioe i is rotated increases the resistance of the disk considerably; in some cases the increase is as great as when the disk itself is roughened. (5.) The resistance of the disk at different speeds varies nearly as the square of the speed. But the exact power of the speed to which the resistance is proportional varies a little for different surfaces. The indices of the powers of the speed to which the resistance is pro- 38 On the Friction of Water, &c. [Nov. 18, portional are almost exactly the same for similar surfaces, in these experiments, as in Mr. Froude’s experiments. (6.) A series of experiments were made on the influence of the temperature of the water on the friction, and the author is not aware that any direct experiments on fluid friction, at different temperatures, have previously been made. The experiments show that the friction diminishes rapidly with increase of temperature. The alteration is so great that even five degrees variation of temperature alters the friction by about one per cent. (7.) When the viscidity of the fluid was increased by dissolving half a hundredweight of sugar in the water of the cistern, the frictional resistance of the disk was increased. But the proportionate increase of resistance was much less than that observed by Coulomb, in a similar experiment at a very low velocity. At the close of the Meeting Professor Graham Bell made experi- ments with his Photophone. 1880.] On the Chemical Composition of Aleurone-Grains. 59 November 25, 1880. THE PRESIDENT in the Chair. In pursuance of the Statutes, notice was given from the Chair of the ensuing Anniversary Meeting, and the list of Offieers and Council nominated for election was read, as follows :— President.—W illiam Spottiswoode, M.A., D.C.L., LL.D. Treasurer.—John Hvans, D.C.L., LL.D. Professor George Gabriel Stokes, M.A., D.C.L., LL.D. Professor Thomas Henry Huxley, LL.D. Foreign Secretary.—Professor Alexander William Williamson, Ph.D., LL.D. Other Members of the Council—William Henry Barlow, Pres. Inst. U.E.; Rev. Professor Thomas George Bonney, M.A., Sec. G.S.; George Busk, F.L.8.; Right Hon. Sir Richard Assheton Cross, G.C.B. ; Edward Dunkin, V.P.R.A.S.; Alexander John Ellis, B.A.; Thomas Archer Hirst, Ph.D.; William Huggins, D.C.U., LL.D.; Professor John Marshall, F.R.C.S.; Professor Daniel Oliver, F.L.S.; Professor Alfred Newton, M.A., Pres. C.P.S.; Professor William Odling, M.B., V.P.C.S.; Henry Tibbats Stainton, F.G.S.; Sir James Paget, Bart., D.C.L.; William Henry Perkin, Sec. C.S.; Lieut.-Gen. Richard Strachey, R.E., C.S.1. Mr. A. J. B. Beresford-Hope was admitted into the Society. The Right Hon. Sir G. Jessel, Knt., whose certificate had been sus- pended as required by the Statutes, was balloted for and elected a Fellow of the Society. Secretaries.— The Presents received were laid on the table, and thanks ordered for them. The following Papers were read :— I. “On the Chemical Composition of Aleurone-Grains.” By S. H. Vines, M.A., D.Sc., Fellow of Christ’s College, Cam- bridge. Communicated by Dr. MicHaEL FostTER, F.RB.S., Prelector of Physiology in Trinity College, Cambridge. Received September 17, 1880. The following is an account of further researches on this subject; abstracts of results have already been given in “ Proc. Roy. Soc.,” vol. 28, p. 218, and vol. 30, p. 387. 60 Dern S. Es Vanes. | [Nov. 25, IV. The Aleurone-Grains of the Sunflower (Helianthus annuus). a. Microscopical Observations.—The sections of the seeds were treated. with ether or alcohol, to remove the oil. The grains became vacuolated on treatment with water. They dissolve completely in 10 per cent. NaCl solution. If they have been previously treated with alcohol, they dissolve readily and completely in saturated NaCl solution; but if they have been previously treated with ether they only become vacuolated. b. Chemical Observations.—The seeds were ground in a hand-mill, and treated with alcohol or ether to remove the oil. The watery extract of the seeds gives no precipitate on boiling. On concentrating the fluid, and then allowing it to filter into alcohol, a dense precipitate is formed. This substance is readily soluble in dis- tilled water, and its solution gives the xanthoproteic and Millon’s reactions, a rose colour with KHO and CuSO, a precipitate on the addition of HNOs,, and an immediate precipitate on the addition of potassic ferrocyanidé after acidification with acetic acid. The 10 per cent. NaCl extract gives a precipitate on boiling, and on saturation with NaCl. The saturated NaCl extract gives, when the seeds have previously been treated with alcohol, a dense precipitate on boiling, and on dilution; if the seeds have been previously treated with ether, the amount of the precipitate is much less; boiling produces little more than a turbidity. These observations, taken together, show that these grains contain : (1) a substance (vegetable peptone or hemialbumose) which is soluble in water; (2) a substance which is soluble in 10 per cent. NaCl solu- tion, precipitable from its solution by saturation with NaCl, and which therefore belongs to the group of myosin-globulins; (3) a substance which is soluble in saturated NaCl solntion, whether the grains have been treated with alcohol or ether, and which therefore belongs to the group of the vitellin-globulins; and (4) a substance which, like the crystalloids of Ricinus described in a previous communication, is soluble in saturated NaCl solution only after previous treatment with alcohol. V. The Aleurone-Grains of the Brazil-Nut (Bertholletia excelsa). a. Microscopical Observations.—Like those of Ricinus, the grains of this plant present no indication of a complex structure when mounted in alcohol; on the addition of water they become transparent, and the crystalloid, as well as the curiously irregular globoid, can be seen. On treatment with 10 per cent. NaCl solution, the whole grain (excepting, of course, the globoid) dissolves. Treatment with saturated NaCl solution produces the same result, 1880.] On the Chemical Composition of Aleurone-Grains. 6L and it is not affected by previous treatment of the grains with ether or alcohol. | b. Chemical Observations—The seeds were crushed in a mortar, and then treated with either alcohol or ether to remove the oil. The watery extract of the seeds gives aslight precipitate on boiling ; the filtrate gives no precipitate on boiling; it gives the reactions of a fluid holding peptones in solution; it also gives a precipitate with HNOs,. The 10 per cent. NaCl extract gives a dense precipitate on boiling, as well as on dilution, and on saturation with NaCl. The saturated NaCl extract gives a dense precipitate on boiling and on dilution. : From these observations it appears that these grains consist of vegetable peptone and of globulins, the one belonging to the myosin, the other to the vitellin group. Weyl has shown (‘“ Zeitschr. f. Physio!. Chem.,”’ Bd. I, 1877) that the crystalloids of these grains consist of pure vitellin; hence the peptone and the myosin must be contained in the ground-substance of the grains. General Remarks. The investigation of the aleurone-grains of a number of different species of plants has shown that, with a few exceptions mentioned _ below, they may be classified under the five types which have been described in this and previous communications. J find, contrary to the opinion of Pfeffer (“‘ Jahrb. f. wiss. Bot.” viii, 1872), that all the aleurone-grains which I have examined are soluble to some extent at Jeast in water; they are also all soluble to some extent in 10 per cent. NaCl solution. In the cases which have been described in detail, the grains were found to be completely soluble in this solution, but in others I found that the grains were only partially soluble in it, residue dissolving either in 1 per cent. Na,CO; solution, or in dilute -KHO, and therefore consisting of some form of albuminate, which may be regarded as altered globulin. The proteid substances detected in the grains may be classified as follows :— I. Soluble in distilled water :— Vegetable peptone (hemialbumose P). II. Insoluble wm distilled water :— a. Soluble in 10 per cent. NaCl solution. Globulins. (a.) Insoluble in saturated NaCl solution,— Vegetable myosin. (B.) Soluble in saturated NaCl solution, after treatment with alcohol,— Substance of crystalloids of Ricinus, &e. 62 On Chemical Composition of Aleurone-Grains. [Nov. 25, (y.) Soluble in saturated NaCl solution after ether or alcohol,— Vegetable vitellin. b. Insoluble in 10 per cent. NaCl solution. Albuminates. (a.) Soluble in 1 per cent. Na,CO3 solution. (B.) Soluble in dilute KHO. I have placed by itself the peculiar proteid which constitutes the erystalloids of Ricinus, and which occurs in the grains of Heli- anthnus, for, although, as I have previously pointed out, it resembles myosin in its properties before treatment with alcohol and vitellin after it, it differs from both these substances in that it is less readily soluble in 10 per cent. NaCl solution. The following is an arrangement of the species examined according to the solubility of the grains. It must be borne in mind, however, that the observations upon which this arrangement depends are, for the most part, simply microscopical, but the close agreement between the results of microchemical and macrochemical methods in the cases which have been given at length justifies an inference as to the probable composition of a grain from the results of one method only. Classification of Alewrone-Grains (Microchemical). I. Soluble ix water :— Peeonia officinalis (type). Ranunculus acris. Aconitum Na- pellus. Anemone Pulsatilla. Nigella damascena. Helleborus foetidus. Amygdalus communis. Prunus cerasus. Pyrus malus. Cynara Scolymus. Scorzonera hispanica. Leontodon Taraxacum. Dipsacus Fullonum. Ipomcea purpurea. Phlox Drummondi. Foeniculum officinale. Impatiens glandulifera. Vitis vinifera. II. Completely, and more or less readily, soluble in 10 per cent. NaCl solution. a. Grains without crystalloids. (a.) Soluble in saturated NaCi solution after treatment with alcohol or ether :— Lupinus hirsutus (type). Vicia Faba. Pisum sativum. Pha- seolus multiflorus. Allium Cepa. Iris pumila (var. atrocceru- lea). Colchicum autumnale. Berberis vulgaris. Althea rosea. Tropeolum majus. Mercurialis annua. Hmpetrum nigrum. Primula officinalis. (B.) Soluble in saturated NaCl solution after alcohol, but not after ether :— Helianthus annuus (type). Platyeodon (Wahlenbergia) grandi- flora. Hrodium gruinum. Sabal Adansoni. Delphinium car- 1880.] Ossijication of the Terminal Phalanges of the Digits. 68 diopetalum. Trolliuseuropewa. Actea spicata. Caltha palustris. Aquilegia vulgaris. Campanula rotundifolia. Dianthus Caryo- phyllus. Brassica rapa. Lepidium sativum. Medicago sativa, Cedrus Deodara. Larix europea. Ephedra altissima. Cyno- glossum officinale. Spinacia oleracea. oO . Grains with crystalloids. (a.) Crystalloids soluble in saturated NaCl solution after treatment with alcohol or ether :— Bertholletia excelsa (type). Adonisautumnalis. Aithusa Cyna- pium. Digitalis purpurea. Cucurbita Pepo. (B.) Crystalloids soluble in saturated NaCl solution after alcohol, but not after ether :— Ricinus communis (type). Datura Stramonium. Atropa Bella- donna. Hlais guineensis. Salvia officinalis. Taxus baccata. Pinus Pinea. Cannabis sativa. Linum usitatissimum. Viola elatior. Ruta graveolens. Juglans regia. Il. Partially soluble in 10 per cent. NaCl solution. a. Entirely soluble in 1 per cent. Na,COz solution :— Pulmonaria mollis. Omphalodes longiflora. Borago caucasica. Myosotis palustris. Clarkia pulchella. 5. Hnutirely soluble in dilute KHO. («.) Grains without crystalloids :— Anchusa officinalis. Lithospermum officinale. Hchium vulgare. Heliotropium peruvianum. lLythrum Salicaria. (8.) Grains with crystalloids :— Cupressus Lawsoniana. Juniperus communis. Euphorbia La- thyris. II. “On the Ossification of the Terminal Phalanges of the Digits.” By F. A. Drxry, B.A. Oxon. Communicated by EK. A. SCHAFER, F.R.S. Received October 5, 1880. [Puates 1, 2.] From the Physiological Laboratory of University College, London. In a preliminary note on the ossification of the terminal phalanges of the digits,* it was stated that the diaphyses of the ungual phalanges differed in their mode of ossification from those of other long bones. The object of the present paper is to give an account of the process of * Ante, vol. 30, p. 550. 64 Miri, ADixey: | [ Nov. 25, . ossification in these phalanges, the peculiar features of which have been found, with slight modifications, to remain constant throughout the whole series of Vertebrata. It will be remembered that all long bones are at an early stage pre- formed in cartilage, and that simultaneously with the calcification of the cartilaginous shaft a deposit of true bone takes place in the invest- ing subperiosteal tissue; so that at a certain stage in development the so-called “‘ primary ”’ or cartilage bone of the shaft is surrounded by a hollow cylinder of “secondary” or true bone. An irruption of the osteoblastic subperiosteal tissue into the cartilage then takes place, which results eventually in the absorption of the primary bone and. its replacement by true osseous tissue, to be in its turn alternately absorbed and renewed so long as the process of growth goes on. Cartilage that is about to undergo calcification presents certain characteristic appearances ; the cells with their cell-spaces become larger, flatten out, and usually show a tendency to arrange themselves in parallel rows, between which, if the change has already been in progress for some time, the lines of calcification may be seen advancing. But whereas in the long bones as a whole,* including the first and. second phalanges of the digits, the alteration of the cartilage cells, followed by calcification of the matrix, appears first in the centre of the shaft and spreads thence pari passu towards the two extremities; in the ungual phalanx it is first seen to arise in the tip or distal extremity of the cartilage, from which point it spreads gradually backwards towards the base of the phalanx (figs. 2, 3). Similarly the subperiosteal deposit of membrane bone im all other cases begins as a thin and narrow ring surrounding the shaft and placed midway between the two extremities, that is to say, in direct relation with the spot where the cartilage first begins to calcify; in the ungual phalanx, however, still preserving its relation with the point of commencing calcification in the cartilage, the deposit of subperiosteal bone first appears as a thin. layer closely applied to the tip of the cartilage and fitting over it like a cap. The ring or hollow cylinder of bone formed in ordinary cases enlarges in two ways, becoming thickened by the continual deposition of new osseous tissue on its outer surface, and at the same time growing at its edges towards the extremities of the shaft, thus accompanying along the outer surface of the cartilaginous diaphysis * Dec. 9.—Further observations have shown that the received account as given above requires some modification. In the ordinary phalanges, which differ from most other long bones by having only one epiphysis, the changes accompanying the calcification of the cartilage do no¢ go on in precisely the same manner towards each extremity. The well-known lines of advancing calcification which run between. rows of single cells parallel with the axis of the shaft, are in the ossifying phalanx only visible towards the proximal end; that is to say, the end which will be crowned by the future epiphysis. As might be expected, there is no difference in this respect — between the proximal ends of the last and of the other phalanges. 1880.] Ossification of the Terminal Phalanges of the Digits. 65 the changes that are taking place within; the whole process resulting in the assumption by the bony cylinder of the form of a dice-box with both ends open, and the median constriction partially or entirely filled in from the outside. Subject to its peculiar conformation, the growth of the bony layer in the ungual phalanx is analogous to the foregoing process. A thickening takes place by the addition of new bone to the outer surface of the cap, and simultaneously with this its edges grow backwards along the cartilage from the tip towards the base (in the same direction as that previously taken by the process of cartilage calcification), so that the cap becomes deeper and deeper, and finally reaches a stage in which it may be compared to a thimble fitting over the cartilaginous phalanx and enclosing it almost up to its base (see fies. 1, 2,3, 4, p,). The deposition of new bone along the outer surface of this cap or thimble may take place relatively much more quickly at the summit than at the sides, so that an expansion is formed, which may be of considerable size, and which no doubt bears a relation to the conformation of the future nail, hoof, or claw (see fig. 2). The next stage in the development of the bone is marked by the irruption of the subperiosteal tissue with blood-vessels and osteoblasts into the shaft at or near the point where the cartilage first began to calcify. This point in all other cases will be found about the middle of the shaft, but in the ungual phalanx, as has been seen, at the tip. In fig. 1, which represents a section in the sagittal plane through the growing ungual phalanx of a foetal cat, the irruption is seen to have taken place at a point just below the tip on its plantar aspect, and this would appear to be the most usual locality. In figs. 2, 3, representing similar sections from the pig and the human subject at an earlier stage of development, the points at which the invasion will probably begin are indicated by the letters 7,7. The advance of the osteoblastic tissue into the carti- laginous diaphysis, its gradual absorption of the primary bone, and the laying down of true osseous tissue in its stead, follow in all cases the . direction already taken by the previous process of calcification; that is to say, in other long bones from the middle towards the two ex- tremities, in the ungual phalanx from the tip towards the base. Thus, to sum up, in the development of the ungual phalanx the three pro- cesses of cartilage calcification, growth of the subperiosteal intramem- branous bone, and deposition of true bone in the shaft along the line of advance of the osteoblastic ingrowth, take the distal extremity of the shaft instead of its middle for their starting-point, and proceed in one uniform direction from tip to base, instead of advancing in two contrary directions at the same time. Hence it seems that the distal extremity of the ungual phalanx corresponds morphologically with the centre of the diaphysis in other long bones. At a period of growth subsequent to the complete ossification of the diaphysis, an epiphysis forms, as is well known, in the cartilaginous 66 Mr. F. A. Dixey. | Nov. 25, head which still remains at the proximal end of the phalanx, and this. becomes united to the shaft in the usual manner. The process of ossification in the terminal phalanx having now been described in general terms, it only remains to notice certain special points of interest that have come under observation during the investi- gation of the subject. It should be first mentioned that the peculiarity described appears to be universal, the same general description applying to any terminal phalanx, whether taken from the manus or pes, and whether belonging to a fully functional or to a mere aborted digit, such as the second and fifth in the manus of the pig. An examination of the growing bone with a view to this point would probably suffice to decide whether the phalanx missing from certain digits in the manus of Pteropus and other bats is really the third (as described, see Flower, “ Osteology of the Mammalia,” 1876, p. 264), or whether it may not rather be the second. A comparison of a series of specimens taken from man, the mole, the rat, the pig, and other animals, seems to indicate that the primitive cartilaginous terminal phalanx exists normally as a subcylindrical bar of comparatively simple conformation ;* while the remarkable modifi-. cations of shape which the adult phalanx assumes throughout the whole range of the mammalia are due to the superstructure erected on this basis by purely intramembranous ossification in the form of the subperiosteal cap, and of what may be called the ungual expansion at its summit. Thus, in the mole, the primitive cartilaginous terminal phalanx presents no distinctive character; it resembles in shape the cartilage of the young pig, as seen in fig. 3, but is relatively a little shorter and thicker. When, however, the subperiosteal growth begins, it is seen that a separate centre for the accumulation of the bony deposit has established itself on each side of the tip of the phalanx, the two being connected by a film of bone over the tip itself, so that. the resulting cap has two summits instead of one. Ata later stage these two summits are found to have increased considerably in height and thickness, and to have encroached upon and partly filled up the interval between them. In this way the growth of the bifid cap pro- ceeds until, after the normal changes, the ungual phalanx of the manus. in the adult mole presents a highly modified appearance, being un- usually long and deeply cleft at its extremity, thus contrasting strongly with the cartilaginous basework on which it was fashioned. Again, in the cat and other carnivora, the hood-like expansion of bone which in the adult is reflected over the base of the claw must owe its origin entirely to a process of intramembranous ossification, since no trace * This shape is liable to a slight modification from the growth of the cartilage at. its proximal end after the process of calcification has already begun at the tip. See description of fig. 2. 1880.] Ossification of the Terminal Phalanges of the Digits. 67 of it is discoverable in the specimen drawn in fig. 1, in which the cartilaginous diaphysis has received its final development, and is already in process of being destroyed. That this structure makes its first appearance at avery late stage in the development of the phalanx, is shown by the fact that it had not yet begun to be formed in another cat embryo 8 centims. long. An examination of the process of erowth in the long tapering ungual phalanges of certain seals might show that for the greater portion of their length they were formed entirely from the ungual expansion of the subperiosteal cap, and had never pre-existed as cartilage. Illustrations of the simple outline of the primitive cartilaginous diaphysis, and of the variety of the forms that may be assumed by its bony superstructure, are afforded by figs. 2, 3, in neither of which has any absorption of the cartilage yet taken place. In fig. 3, taken from a feetal pig, the young phalanx, which is destined to support a hoof, is seen to have its subperiosteal cap greatly enlarged on the palmar aspect. As an example of the process in birds, the terminal phalanges of the second and third digits of the manus, and of all the digits of the pes, were examined in a young sparrow. ‘The calcification of the cartilage and its attendant changes, and the formation of the subperiosteal cap, were seen to be starting from the tip, and proceeding in exactly the same manner as already described ; specimens, however, to show the invasion of the cartilage by osteoblastic tissue could not at that time be conveniently obtained. Among reptiles, a young alligator showed the same processes with great clearness; but it was again impossible to procure a specimen sufficiently advanced to exhibit the course of the osteoblastic irruption. An interesting modification of the process is furnished by the am- phibia. Fig. 4 represents a section in the sagittal plane through the last two phalanges of the middle digit of the fore-foot of the Prviene. In this specimen, which there was every reason to suppose adult, no irruption whatever of osteoblastic tissue has taken place in the last: two phalanges, which accordingly consist each of a core of partly calcified cartilage ; in the case of the penultimate phalanx surrounded by the hollow cylinder or dice-box of true bone already alluded to, in the case of the terminal phalanx plunged into a deep receptacle, also of true bone, which is in fact the subperiosteal cap.* Thus a state of things which in the higher Vertebrata belongs only to a temporary stage in embryonic development, is in the Proteus persistent through- out life. The growth and calcification of the cartilage and the for- mation of the subperiosteal layer of bone proceed, it may be assumed, in the regular manner; but having advanced so far the process stops, * From the only specimens procurable, no conclusions could be arrived at with regard to the condition of the prommal phalanx of the digit, or indeed of any other of the bones. 68 Mr. F. A. Dixey. | Nov. 25, and the final stages marked by the invasion of the calcified cartilage and its replacement by true bone are in these two phalanges never reached at all.* [Note.—Another instance of arrested development in the digit of the Proteus is afforded by the interphaiangeal joint represented in the same figure. The cartilage, with a slight alteration in the size and relative number of its cells, is seen to be quite con- tinuous between the heads of the two phalanges, nor does it exhibit the least sign of an articular cavity. The movement allowed by such @ jolt must be limited, but that some does take place is rendered _ probable by the position of the tendons seen at et and jt. Specimens of intramembranous ossification in the Proteus are remarkable as showing with great distinctness the original deposition of bone in the form of globules, after a manner strictly comparable with the growth of dentine.| In the newt the ossification of the terminal phalanx pro- ceeds in the same way as in the Proteus, and is arrested at the same stage; but the penultimate phalanx undergoes the osteoblastic inva- sion, and is remodelled in true bone in the usual way.} The specimens from which the figures and descriptions were taken were all hardened in strong spirit, most of them having been previously decalcified in weak chromic or saturated picric acid. They were then imbedded by the cacao-butter method and ent by hand or by Leiser’s microtome. The greater number were stained as sections with magenta, but some were stained in bulk with logwood, carmine, or both, before being subjected to the process of imbedding. The best results were obtained by the employment of a freshly-prepared solution of magenta in oil of cloves. DESCRIPTION OF PLATES. Figure 1. Section in the sagittal plane through the terminal phalanx of a digit in the pes of a foetal cat 4 centims. long. Decalcified in chromic acid and stained with magenta. c, the unaitered cartilage of the base of the phalanx ; towards the tip the cells are seen to be assuming the form and * This condition resembles one that is liable to occur in the costal cartilages of the mammalia, where a layer of membrane bone (in these cases subperichondrial) is found enveloping a core of cartilage which may or may not be calcified. * Dec. 9.—The uncertainty that prevails respecting the homologues of the limb- elements in fishes, renders it difficult to say how far this class can be brought under the rule above laid down for the higher vertebrates. In connexion with this sub- ject, which is still under investigation, the following facts are noticeable :—(1.) That in the limbs of all fishes which possess these appendages there is found at an early stage a cartilaginous endoskeleton, which may persist as such, or undergo various degrees of subsequent ossification. (2.) That to this set of elements is superadded in many fishes a series of dermal deposits of bone (with or without lacune), the local relation of which to the endoskeletal elements corresponds with that of the subperiosteal bony growth to the terminal cartilaginous phalanx in the higher vertebrates. 1880.] Ossification of the Terminal Phalanges of the Digits. 69 arrangement characteristic of approaching calcification ; at ec the calcifi- cation is complete. @ marks the furthest point yet reached by the osteoblastic invasion, where secondary areole containmg numerous osteoblasts have been formed by the partial demolition of the calcified cartilage ; and at 7 the ingrowth of the subperiosteal tissue with blood- vessels and osteoblasts is seen to have begun close to the tip on its plantar aspect, and to be spreading back towards the base of the phalanx, having effected the total absorption of the primary bone in the neighbourhood of the point of invasion; p, the subperiosteal cap of intramembranous bone, at this stage thin and incomplete; osteogenic fibres and osteoblasts are seen along its outer border, and lacunee in its substance. pp, layer of bone marking the former limit of the sub- periosteal cap, which has suffered to a great extent from absorption, and is being remodelled on a larger scale. ft, et, flexor and extensor tendons, some fibrous bundles from which are seen to be prolonged into the growing bone. bv, blood-vessels in the osteoblastic tissue. [Maenified about 85 diameters. | Figure 2. Sagittal section through the terminal phlanax of the fifth digit of the right manus of a human foetus about the fourth month. Decalcified in picric acid, stained with magenta. ec, unaltered cartilage; cc, calcified cartilage. At , a region occurs where the cartilage presents unusual character- istics, the cell-spaces being smaller and the matrix more deeply stained than in the areas on either side, which show the more typical appear- ance of primary bone. jp, the subperiosteal cap of intramembranous bone, with osteogenic fibres and osteoblasts. Many fibrous bundles, con- tinuous with the tendons et and f#, are seen as in the last figure to be prolonged into the bone. The ungual expansion at the summit of the cap eonsists of two masses (d and pa), separated by a notch, 7, which may represent the point of future irruption. A series of sections from the same digit shows that what appears here as a notch is really a pit sunk in the middle of the ungual expansion. Of the two masses (d and pa), the one towards the dorsal surface (d) is characterised by possessing in proportion far fewer lacunze with their included bone-cells than the protuberance (pa) on the palmar side. This distinction applies also to the dorsal and palmar sides of the cap as far as they extend. In this specimen no irruption has yet taken place, and the cartilage preserves its original form. The conical contour indicated by the figure is due to the fact that expansion can only take place in cartilage as yet untouched by the process of ossification, its growth when this begins being checked either by the calcification of its own matrix or by the obstacle opposed to it by the investing subperiosteal layer of bone. Hence, only the proximal area of the cartilaginous phalanx is capable of lateral expansion, and since the growth of the cartilage continues for a long time after the beginning of the process of ossification at its tip, the conical shape seen in this and other instances results. The same cause produces the well-known hour- glass form of the cartilage seen during the growth of other long bones. [Magnified 65 diameters. ] Figure 3. Sagittal section through the terminal phalanx of one of the middle digits of the manus of a feetal pig 6 centims. long. Decalcified in picric acid, stained with magenta. c, unaltered cartilage; cc, calcified cartilage. p, subperiosteal cap of bone, which is greatly thickened on the palmar aspect of the phalanx. A deep cleft is seen separating the greater bulk VOL. XXXI. G 70 Mr. F. A. Dixey. [Nov. 25, of this part of the cap from a thin layer of bone, pp, which is closely adherent to the cartilage ; in the interval a large blood-vessel is seen cut across, and a smaller branch runs up towards 7, which is near the point where the osteoblastic irruption will in all probability begin. Other blood-vessels are seen at bv. This section represents very nearly the same stage in ossification as fig. 2. [Maenified about 85 diameters. | Figure 4. Sagittal section through the last two phalanges of the middle digit of the manus of Proteus anguinus. c, unaltered cartilage; cc, cartilage calcified, but exhibiting no other change. In the terminal phalanx the distal extremity of the cartilaginous core is seen to be narrowed down to a single row of cells with the intervening matrix. p, subperiosteal cap of bone. 46, cylinder or dice-box of bone enveloping the shaft of the penultimate phalanx. J, 7, lacune. 7, interphalangeal joint. et, ft, ex- tensor and flexor tendons. This specimen was stained with magenta, but not decalcified, for which reason the bony tissue appears light and transparent, instead of being deeply stained, as in the preceding figures. The permanently calcified cartilage shows no alteration in the arrange- ment or size of the cells, which in this instance are remarkably large and regular inform. ‘The animal was believed to be fully adult. [Magnified about 85 diameters. | (Received October 27, 1880.) The fact that the process of ossification in the terminal phalanges begins at the distal extremity, and advances towards the base, has been observed as regards the human fcetus, by M.M. Rambaud and Renault (“‘ Origine et Développement des Os,” Paris, 1864). After describing the order in which the first and second rows of phalanges are ossified in the hand, they continue, ‘‘ De méme pour les troisiémes, ou elle (i.e., ossification) débute par le rebord unguéal” (p. 214). In speaking of the foot, their language is more explicit, ‘ Les troisiemes phalanges commencent as’ossifier par lextrémité antérieure, puis de la Vossification s’étend vers l’extrémité postérieure, laissant toujours un appendice cartilagineux qui se transforme en épiphyse ”’ (p. 240). These authors, however, make no attempt to describe the process, nor to determine how far it is participated in by the cartilage and the superiosteal membrane respectively ; neither do they mention the ungual expansion, or the enveloping cap. Moreover, the statements already quoted from the text of their work are entirely ignored in the plates, where in every figure that contains a representation of growing phalanges, and even in the figures especially referred to as illustrative of the above-quoted statements, the terminal phalanx is made to ex- hibit no difference whatever from the rest in its mode of ossification. For instance, in Plate XXI, fig. 1, it is drawn with a very evident cartilaginous head at each extremity; yet this figure, in the words of the authors themselves, “‘ représente exactement l’état de l’ossification de la main a la naissance.” (Ibid., p. 215.) Dixey. Proc. Roy. Soe Wee JEDI ay e OL West, Newman & Co. Lith. Ye Proc Foy. S0e.Vol. 31 Fee. Dixey. cc West, Newman & Co. ith. 1880.] Ossification of the Terminal Phalanges of the Digits. 71 A recent paper by Dr. M. Kassowitz (‘‘ Die Normale Ossification, etc.,” in 8. Stricker’s “ Medizinische Jahrbiicher,” 1880), is accom- panied by a plate (Taf. X), in which there is diagrammatically repre- sented a sagittal section through a finger of a human foetus of slightly earlier age than fig. 2, infra. The cartilage of the terminal phalanx is calcified at its distal extremity, and the calcified portion is en- veloped in a thin cap of subperiosteal bone; so that if allowance be made for the diagrammatic nature of the figure, it affords a fair idea of the actual condition of the phalanx as above described. Speaking of this figure, however, the author says, ‘‘ An der dritten Phalanx ist die Verkalkung schon bis an das distale Hnde vorgedrungen, so dass nur das der zweiten Phalanx zugekehrte Ende knorpelig geblieben ist. In der That ist auch schon das ganze Endstiick mit einem periostal gebildeten knochernen Ueberzuge versehen.” (Op. cit., p.279.) It is evident from these words, that the author believes the ossification in this phalanx to have begun-at some point other than the distal end of the shaft (presumably near its middle), and to have proceeded thence at different rates towards the two extremities; the only distinction between this and the other phalanges being that here the area of uncalcified cartilage at the distal end has quickly disappeared before the advance of calcification from the centre of the shaft; while at the proximal end the corresponding area still persists; as it does at both ends in ordinary cases. Farther on, he repeats this explanation, and seeing the necessity of providing for the future growth of the bone at its distal extremity, after the disappearance of the supposed cartila- ginous head, he rightly assigns the entire task to the periosteum, which has already enveloped the cartilage with its bony cap :—‘‘ In der dritten Phalanx schwindet, wie wir friither gesehen haben, der Knorpel an dem distalen Hnde vollstiindig, indem die Verkalkung schon friihzeitig bis an die Oberfliche vorriickt und auch die Kuppel einen knochernen Ueberzug vom Periost aus bekommt, welches letztere weiterhin auch das sehr geringe Lingenwachstum an dem distalen Hnde besorgen muss.” (Ibid., p. 280.) These extracts will suffice to show that Dr. Kassowitz, while correctly describing the appearances presented by the terminal phalanx in a certain stage of its growth, has failed to draw the proper inferences from them. Had he compared specimens of a somewhat earlier or later stage with the one he has figured, he would probably have been led to recognise the fact that the processes involved in the ossification of this bone spread gradually backwards from the tip; instead of, as he imagines, ad- vancin g rapidly towards it. 72 Mr. J. N. Lockyer. On a Sun-Spot. Nov. 25, III. «On a Sun-Spot observed August 31, 1880.” By J.N. Lockyer, F.R.S. Received October 26, 1880, The recent activity in solar spots has enabled me to test the hypo- thesis I put before the Society on December 12th, 1878, by observing whether the velocity of the up-rush or down-rush of the so-called iron vapour in the sun was registered equally by all the iron lines, as it should be on the received hypothesis. The observations already made, though few in number, indicate that while motion is shown by the change of refrangibility of some Jines, other adjacent lines indicate a state of absolute rest. Thus, in an observation of a sun-spot on August 31st, 1880, when the iron line at 5207°6 was doubly contorted, indicating an ascending and descend- ing velocity of about fifteen miles a second, the two adjacent iron lines at X 6203°7 and 5201°6, visible in the same field of view, were unaffected. I send this paper to the Royal Society with all reserve, in order to call the attention of other observers to the point, as I fear it is only too probable that fogey weather will stop all observations here. IV. “On Methods of Preparing Selenium and other Substances for Photophonic Experiments.” By Professor GRAHAM BELL. Communicated by the PRESIDENT. ) [ Publication deferred. ] 1880. | Annwersary Meeting. re) November 30, 1880. ANNIVERSARY MEETING. THH PRESIDENT in the Chair. The Report of the Auditors of the Treasurer’s Accounts on the part of the Council was presented, by which it appears that the total receipts during the past year, including a balance of £1,264 6s. 8d. carried from the preceding year, amount to £8,592 12s. 9d.; and that the total expenditure in the same period, including purchase of stock, amounts to £7,397 7s. 8d., leaving a balance at the Bankers’ 01 £1,178 9s. 7d., and £16 15s. 6d. in the hands of the Treasurer. The thanks of the Society were voted to the Treasurer and Auditors. The Secretary read the following Lists :— Fellows deceased since the last Anniversary. On the Home List. Ansted, David Thomas, M.A. Bell, Thomas, F.L.8. Belper, Edward, Lord, M.A. Brodie, Sir Benjamin Collins, > Bart. M.A., D:C.L. Budd, William, M.D. Clarke, Jacob Lockhart, M.D. Cooke, Edward William, R.A. Hrle, Right Hon. Sir Wilham, sali. Guest, Edwin, D.C.L., LL.D. Hamilton, The Very Rev. H. Parr, Dean of Salisbury. Hampton, John Somerset Paking-. ton, Lord, G.C.B. Lassell, William, LL.D. Maceneill, Sir John, LL.D. Miller, William Hallowes, M.A., D.C.L. . Napier, James Robert. Plowden, Wiliam Henry Chi- cheley. Sharpey, William, M.D., LL.D. Stephens, Archibald John, Q.C., LL.D. Taylor, Alfred Swaine, M.D. On the Foreign List. Peirce, Benjamin. Withdrawn. Robert Bickersteth, Lord Bishop of Ripon. Change of Name and Title. Lane- Fox, General, to Pitt-Rivers. Lowe, Right Hon. Robert, to Viscount Sherbrooke. 74 Anniversary Meeting. [ Nov. 30, Fellows elected since the last Anniversary. Attfield, Prof. John, Ph.D., F.C.S. | Hughes, Prof. David Edward. Beresford-Hope, Alexander James | Jeffery, Henry M., M.A. Beresford, LL.D. Jessel, Right Hon. Sir George, Blanford, Henry Francis, F.G.S. Knt. Clifford-Allbutt, Thomas, M.A., | M’Coy, Prof. Frederick, F.G.S. M.D., F.L.S. Moulton, J. Fletcher, M.A. Dallinger, Rev. William Henry. Niven, Prof, Charles, M245, Dyer, William Turner Thiselton, F.R.A.S. M.A., F.L.S. Northbrook, Thomas George Godwin-Austen, Lieut.-Col. Henry Baring, Earl of, D.C.L., G.C.S.1. Haversham. Rae, John, LL.D. Graves, The Right Rev. Charles, | Reynolds, Prof. J. Emerson, M.D. D.D., Bishop of Limerick. Tilden, William A., D.Se. The President then addressed the Society as follows :— ‘“‘ Happy is the nation that has no history,’—none, that is to say, in the matter of political events, of diplomatic victories or defeats, of warlike achievements, or other staple topics of record, as history is wont to be written. And such, in fact, has been the state of our own community during the past year. We have no great convulsions to chronicle, nor changes to relate, no controversies with other bodies, nor grievances at issue between us and the State. But, as with a nation, so also with a society, an absence of these more striking, and perhaps superficial, features, is certainly compatible with a healthful internal growth, and with a steady development of the purposes for which our organisation was originally intended. In the course of the year now ended, we have, naturally, lost some of our elder Fellows; but, numerically at least, our losses have not been so great as during the previous year, nor have they fallen so heavily on our younger members. Among those who have dropped from our ranks, several had already, on account of declining powers, withdrawn from active participation in our proceedings, and had thereby prepared us for their final departure. Among these, two stand prominently forward, men who, through long and faithful service to science and to our Society, deserve to live a long and oft- repeated life in the memory of their friends. Of Professor Miller it is difficult adequately to speak. His acioduee work has been well, but not too fully, described in the obituary notice published in our ‘‘ Proceedings.” Older than myself, and older than other existing officers of the Society, he seemed to belong to an earlier generation. Whether it was due to the number of his years, to the plenitude of his knowledge, to the judicial character of his mind, to his calm but ever ready response to an inquiry, or still more probably to a combination of all these qualities, certain it is 1880.] President's Address. 15 that his friends generally by a tacit consent regarded him as a mentor in the scientific world. And yet, notwithstanding this gravity of demeanour and severity to himself, no one imbibed more thoroughly, nor more liberally contributed to the genial spirit which has always actuated our officers, and even to the good stories which sometimes circulate about a scientific gathering. Of Dr. Sharpey I might speak in almost the selfsame terms, except- ing only that more constant intercourse on the business of the Society, and on other occasions elsewhere, drew our ties of friendship some- what more closely than in the former case. Dr. Sharpey’s life and work are too well told in the obituary notice by an old comrade of his, he was himself too well known, and too widely esteemed, to: need any comment of mine; and I will not disappoint my own feelings, nor those of my hearers, by any inadequate words on my part. The name of Mr. Lassell is one which, whether regarded from the point of view of his scientific work, or from that of private friendship, would be passed over by no one who had the advantage of a know- ledge of the former, or of experience of the latter. His name seems to fall in so naturally with those of Herschel and Lord Rosse, that we are apt to class him with the old school. He was, however, of that school only in the best sense; he carried the weight, and earned the dignity which we accord to them; but to his last days, he was as fresh and sympathetic with modern work as the generation which is now suc- ceeding to his. The details of his achievements in instrumental construction, themselves real contributions to seience, and of his astronomical discoveries, will be given elsewhere. I will here only add, that in him we have lost a Fellow whose presence was always welcome, and whose assistance and advice were as valuable as they were freely given. In Professor Ansted we have lost a familiar face, a pleasant writer on science and its accompaniments, and an active promoter of its applications. : I turn now to another who has passed away, and find in him another type of character among our Fellows, namely, Lord Belper. From the member of his family best able to judge, I have the following account of the chief occupations of Lord Belper’s life. From his early years his attention was engaged in all questions of political and social interest, especially in free trade, law reform, political economy, and the advance of education. He enjoyed the society of Jeremy Bentham, and an intimate and frequent intercourse with James Milland John Stuart Mill. Among the friendships formed in his youth, and terminated only by their death, I may mention the names of Macaulay, John Romilly, McCulloch, John and Charles Austen, George Grote, and Charles Buller. And, to use his own words, ‘“‘ Days passed in the society of such men can never be forgotten.” 76 Anniversary Meeting. [ Nov. 30, Throughout his life he loved and honoured science. To this he had an hereditary claim. His father, Mr. William Strutt, was for many years the centre of all philosophical and scientific interest in Derby, and the intimate friend and associate of Dr. Darwin. Lord - Belper loved to recall this while delighting in the researches of Dr. Darwin’s far more illustrious grandson. Although he never devoted himself to any special branch of science, he maintained the deepest interest in all scientific research, and in every new discovery. His life had comprised a period of great and active progress, the development of which he had watched with an interest which appeared to deepen as he grew older; and the great solace of his declining years was the thought (which would often rouse him to enthusiasm) of what had been achieved within his memory towards advancing the comfort and happiness of mankind. During his long connexion with University College, of which he became President at Mr. Grote’s death, in 1871, few things gave him greater satisfaction than the generousendowment by his friend, Mr. Jodrell, of the Pro- fessorship at that College for the furtherance of Physiological Science. If in Lord Belper we have an example of one of the many ties which link our body with the outer world, in Mr. EH. W. Cooke we have another. Art as well as Politics may have a scientific aspect; and the faithful delineation of the features of nature is an aid with which science could not easily dispense. Mr. Cooke was a keen observer of natural objects, which he viewed with a trained eye and a cultivated mind; and much as he rejoiced in sketching the busy scenes of the seaboard towns of Hurope, he never was more happy than when pro- ducing, among the rocks, pictures which may almost be described as geological. On the last of our fallen leaves is inscribed the name of Sir Ben- jamin Collins Brodie, son of our late President; himself no mean contributor to the science which he cultivated, and no unworthy representative of the firmness of character and independence of thought which have always been connected with his father’s name. Others there are, whom we have lost, to a full tale of twenty; but the narration of their story would be both sad and long. In regard to our property, I have little to report. The regulations respecting the income arising from the Fees Reduction Fund have been duly carried out by our Treasurer; and the other special funds stand much as at last anniversary. Several improvements have been effected in the Acton Hstaie, under the sanction of the Council; and some negociations have been entered into for the sale of the entire estate, which are still pending. The Society’s finances generally are, as the balance-sheet will show, in a healthy condition, and appear to justify the hope that they will suffice for the large claims upon them for printing our publications. 1880. | Presidents Address. AG Although we are more concerned with the quality than with the quantity of communications made to the Society, it may not be with- out interest to observe that the number of papers received this year has been in excess of that in any previous year, at all events since 1872, inclusive. The following is a table of the numbers during the last nine years :— 1872 nis “pi 99 papers received. 1873 on Hip DER yyeitds : 1874 hie ie Cielito . 1875 He as Sou. i 1876 ee bine AS eh iy 1877 ae os ile is 1878 8 sll og LD ipainer ‘i 1879 a8 dignonyall Ne aguas " 1880 i pak pred As ep aee ef and we may conclude that these have contained good matter from the fact that of the ‘“‘ Philosophical Transactions” for the current year, Parts 1 and 2, already published, contain no less than 900 pages and 33 plates. We have reason to hope that the volume will be completed very early in 1881. Of the “‘ Proceedings,”’ volume 29 was completed in February, and volume 30 in August last. In my address last year, I suggested that the hour of our weekly meetings might, perhaps, with advantage, be changed from the evening to the afternoon. That suggestion was approved by the Council, and by their direction a circular was addressed to all the Fellows of the Society, inviting an expression of opinion upon the question. Those of the Fellows who, living at a distance, are unable to attend our meetings, mostly abstained from making a reply. But in the answers actually received, the preponderance of opinion was so strongly in favour of the change, that the Council took the necessary steps for altering the statute by which the hour of meeting was formerly fixed. Notice of the alteration was sent to all the Fellows. The regulation of the hour of meeting is now in the hands of the President and Council. The attendance at our meetings has certainly not diminished since the change, and some of our Fellows, to whom the evening hour was inconvenient, have become constant attendants. The Council now usually meet at 2.0 p.m., instead of 3.0 P.m., in order to be ready for the meeting of the Society at 4.30 p.m.; and IT am happy to add that it has not yet been found necessary to call the Council or the Committee of Papers together on any other than the usual days. In the permanent staff of the Society no change has taken place. 78 Anniversary Meeting. [Nov. 30, T regret, however, to record the death of Mr. Henry White, who for many years was chief assistant in the compilation of the great Catalogue of Scientific Papers. At an earlier stage of the work his loss would have been still more serious; but in a long course of training he succeeded so well in imparting his own careful and methodical mode of work to those under him, that the Council felt justified in making trial of his son to take his place. With the result of this trial, as shown in continuing the preparation of a new edition of the catalogue of the Society’s Library, the Council have reason to be satisfied. Of this new edition, the first portion, 220 pages, containing our large collection of ‘‘ Transactions”’ and ‘‘ Proceedings ” of Academies and Societies, and other scientific periodicals, is in type, and will shortly be printed off. The verification of titles of our scientific books generally is so far advanced as to warrant the expectation that a large instalment of this portion of the catalogue will soon be in the printers’ hands; after which we anticipate no further delay. In regard to the Library, a question has arisen’as to how far purely literary works, which occupy much space, should be retained. Among them there are doubtless.some which add neither to the utility nor to the scientific importance of our Library, but there are also some early printed books, bibliographical treasures, which are worthy of a place in any collection. It is proposed to have these carefully put in order, and to place them ina case: by themselves. Among these, there may be mentioned :— Caxton’s Chaucer, 1480. Pynson’s Chaucer, 1492. Speght’s Folio Chaucer, 1598. Ciceronis Officia et paradoxa, Fust. 1466, vellum. The generall historie of Virginia, Lond. 1632. Bonifacius. Sextus decretalium liber. Ven. 1566-7. Plautus, 1482. Seneca, 1490. Ovid, 1485. Statius, 1490. Plutarch, 1485. Herodotus, 1494. Homer, 1488. For bringing into prominence these as well as other features of our miscellaneous, 7.e., non-scientific, books, we are greatly indebted to the care and knowledge brought to bear on the subject by Mr. Tomlinson, and by our Treasurer. Although it is doubtless undesirable to propose, without sufficient cause, alterations in our Statutes, or even in our practice, it is still often worth while from time to time to discuss questions involving such alterations in order that we may be prepared for a deliberate judgment whenever occasion may arise. Among such questions there 1880. ] Presidents Address. 79 is one upon which I have often heard opinion expressed, and upon which opinion has always weighed in the same direction: I allude to the period of office of those elected to serve on the Council of the Society. By the terms of our charter ten of the ordinary members retire every year; and as it is our custom to remove six according to seniority and four in respect of least attendance, it rarely happens, although the contrary is possible, that any Fellow, except those holding the posts of President, Treasurer, or Secretary, should remain in office more than two years. Hxperience, however, appears to show, that for a member serving on the Council for the first time, there is so much to learn, so many heads of business demanding attention which do not in general come before the Fellows at large, that his first year is occupied quite as much in ascertaining his duties as in actively per- forming them. This objection is in some degree met by selecting for the ten incoming members five who have served before and five who have not so served; but, nevertheless, there is usually an interval of several years between two periods of office, and as a matter of fact we often lose a member of Council at the moment when his advice is becoming most valuable to our body. Iam aware of the great convenience attaching to our present im- personal mode of selecting the members to retire in each year, and am not at present prepared to suggest any specific alteration. But the great confidence which the Society has, especially of late years, placed in its more permanent officers, and the power which naturally accrues to them from the comparatively short tenure of office by the other Members of Council, appear to me to be points of which the Society should not lose sight. On the part of the officers, I think it right to state that we are very sensible both of the honour which is thus done to us, and of the responsibility which is thereby entailed, and that we hope never to discredit the one, nor to abuse the other. And having said so much, we are quite willing to leave the matter in the hands of the Society to be taken up whenever they see reason so to do. It will be in the recollection of the Fellows that the position of the Royal Society in respect of the Government Fund of £4,000 per annum is different from that in relation to the Government Grant of £1,000 per annum. in the latter case the sum is placed unreservedly in the hands of the Society for promoting scientific investigation, subject only to an annual report to the Treasury of the sums granted; and, in admi- nistering it, the Society has in no case applied it to the personal remuneration of the applicant. In the former case, the Society has been requested to advise the Science and Art Department as to the distribution of the grant, not only for the direct expenses of investiga- tions but also for personal remuneration for the time expended on them, whenever the circumstances and wishes of the applicant appeared to render this desirable. The responsibility of this advice hes with a 80 Anniversary Meeting. [| Nov. 30, Committee similar to that of the Government Grant, but with the addition of the Presidents of certain learned bodies and societies, nominated for that purpose by the Government. , The recommendations made by the Committee each year are annually published in the “‘ Proceedings,” so that the public will have had full information as to the distribution of the grant; while the Fellows have the opportunity of seeing the nature of applications made, and the extent to which it has been found practicable to meet them, as re- corded in the minutes of the Council of the Society. One of the points which is perhaps beset with the greatest difficulty is that of the so-called “ personal” grants. On the one hand, it has been argued that it is desirable to enable the man of small means to devote to research a part of his time which he could not otherwise afford to give; but, on the other, the question has been raised whether it be wise, even in the interests of science, to encourage anyone not yet of independent income to interrupt the main business of his life. It is too often assumed that a profession or a business may be worked at half speed, or may be laid down and taken up again, whenever we like. But this is not so, and a profession temporarily or even partially laid aside, may prove irrecoverable; and the temptation to diverge from the dull and laborious path of business may prove to have been asnare. Without proposing to exclude from possible aid in some shape or other those cases where personal assistance may be safely offered, it has been suggested that many such cases may be practically met by grants for the employment of an assistant, instead of grants to the applicant himself. j There is another fundamental difference between the position of the Government Grant of £1,000 per annum and the Government Fund of £4,000 per annum, which appears to me to be of material im- portance in the interests of science. The former is an absolute grant from the Treasury made to the Society for scientific purposes. It may be used wholly, or in part, during the year in which it is made, and the balance, if any, may be carried over by the Society to the next or even to succeeding years. The latter is a vote to the Science and Art Department, on the disposal of which the Society is consulted. Like all other similar votes, any unused balance reverts to the Treasury, and is to that extent lost to the purpose for which it was intended. I cannot help thinking that, if any such balances could be reserved and kept in hand, provision might be made for some larger purposes than those to which the fund has hitherto been devoted. And, even if having this end in view, the Committee should not see its way to recommend some of the smaller applications, it may be fairly questioned whether the smaller grants might not find a more appropriate place among those of the Donation Fund of this Society, or of the British Asso- ciation, or among some of those separate funds which, through the 1880. | President's Address. 81 liberality of individuals, are now growing up among the special societies. I am glad to record the fact that, upon the recommendation of men of science, Her Majesty has been pleased to grant pensions on the Civil List to the widows of two of our late Fellows, viz., to Mrs. John Allan Broun and to Mrs. Clifford. Last year two volumes containing a collection of the late Professor Clifford’s general lectures and essays were brought out. It is hoped that during the present winter a collection of his mathematical papers will be published. The contributions to science by the late Pro- fessor Rankine have recently been placed in the hands of the public. While very sensible of the obligations under which the scientific world is placed by these posthumous publications, I cannot refrain from alluding to our obligations, even greater if possible, to those who during their lifetime are willing to re-issue their own scientific memoirs, and to give us thereby not only the convenience of ready access, but also the advantage of their own subsequent reflections on the subjects of which they have treated. And at this moment I desire to mention more particularly the mathematical and physical papers of our Senior Secretary, Professor G. G. Stokes; and, while expressing our gratitude for the volume which has already appeared, I would express also our sincere hope that another instalment from the same source may shortly follow. Among the subjects which at one period of the last session of Par- hament engaged the attention of the Government was that of the law relating to vaccination ; and a Bill was introduced intended to remove some of the practical difficulties in carrying out the existing law. While fully admitting the difficulties in question, the remedy proposed appeared to trench so closely upon the application at least of a scien- tific principle, and at the same time to be so important in its practical aspect, that I ventured (although the Council was not sitting) to con- sult the Presidents of the Colleges of Physicians and of Surgeons, and that of the Medical Council, about addressing the Government on the subject. This resulted in a joint deputation to the President of the Local Government Board, in which I took part as President of the Royal Society. The Council on my reporting the matter to them at their first meeting after the recess, expressed their approval. The Bill in question was withdrawn. The Royal Commission on Accidents in Coal Mines, the appointment of which I mentioned in my address of last year, have been occupied principally in bringing together a body of valuable evidence on the causes and prevention of accidents in mines generally. The Com- mission have also visited a number of minesin which serious accidents by explosion have taken place, or in which certain phenomena con- nected with the occurrence of fire-damp were to be studied. They 82 Anniversary Meeting. [ Nov. 80, have also instituted a series of experiments on the behaviour of various safety lamps in mixtures of natural fire-damp and air. These experi- ments they are about to renew during the winter. They also contem- plate carrying out experiments in blasting rock and coal by methods which will check the production of flame, and which are thereby cal- culated to obviate the danger of igniting fire-damp. The report of the voyage of H.M.S. ‘‘ Challenger,” to which the scientific world has been looking forward with so much interest, is now so far advanced that one volume of the ‘‘ Zoological Memoirs ” will appear immediately. In addition to this a second volume may be expected within a year. The first volume of the whole work, “‘ contain- ing a short narrative of the voyage, with all necessary hydrographical details, an account of the appliances and methods of observation, a running outline of the results of the different observations; and a chapter epitomising the general results of ‘the voyage,” together with the second volume containing the meteorological, magnetic, and hydro- graphic observations, will probably be published within the same period. ‘The general report on the zoology of the expedition will consist of about fifty distinct memoirs, which will occupy from ten to twelve volumes.” It has been arranged “to print the Zoological Reports as they are prepared, and to publish them as soon as a sufficient bulk of memoirs is ready to form a volume. Copies of each memoir may also be had separately, in order that working naturalists fnay have them in their ‘hands at the earliest possible date.” T'wo more volumes on the geology and petrology, and one on the general chemical and physical results, will probably complete the series. Into zoological details 1 am not competent to enter, but one among them is of great interest, namely, the fact that notwithstanding the pressure and absence of light, there is no depth-limit to animal life. As the Council of the Meteorological Office is nominated by the Council of the Royal Society, and as the Annual Report of the Office is submitted to the Royal Society, I think it right to mention a few points connected with the work of that Department during the past year. 1. A method of recording the duration of bright sunshine by the charring of an object placed in the focus of a glass sphere, freely exposed to the rays of the sun, was devised by Mr. J. F. Campbell, of Islay, in 1856; and instruments, being modified forms of that originally proposed, have been employed for some time at Greenwich, at Kew, and at a few private observatories. ‘Certain difficulties in adjusting the paper about to be charred to the path of the burning spot, which had hitherto prevented the adoption of Mr. Campbell’s invention as a part of the ordinary equipment of a meteorological observing station, have been at last successfully overcome by an arrangement designed by Professor Stokes ; and thirty stations in the 1880.] President's Address. 83 British Isles have now been supplied with instruments of the pattern proposed by him. We may thus hope to obtain in future a sufficient record of a meteorological element, which is of primary importance in its relations to agriculture, and to the public health, but which has hitherto been very imperfectly registered. : 2. The climatology of the Arctic regions, in addition to its importance as a part of the general physics of the globe, possesses a special interest in connexion with geographical exploration. As a contribution to our knowledge of this subject, the Meteorological Office has entrusted to Mr. R. Strachan the task of bringing together, and discussing on an uniform plan, the results of the observations taken at intervals during the last sixty years, in the region extending from the meridian of 45° W. to that of 120° W., and from the parallel of 60° to that of 80°, either at land stations or at the winter quarters of British and American expeditions. A considerable por- tion of this discussion has been already published; the remainder may be expected in the course of next year. 3. Another publication of the Meteorological Office may be men- tioned as serving to mark the advance in meteorological theory, which has been achieved during the last fifteen years. The old “ Barometer Manual and Weather Guide” of the Beard of Trade has been replaced, so far as it relates to the weather of the British Isles, by a work entitled “‘ Aids to the Study and Forecast of Weather,” pre- pared under the direction of the Meteorological Office by the Rev. W. Clement Ley. Though some of the views put forward in the later work may, perhaps, be regarded as not sufficiently established by observation, yet a comparisou of the two works cannot fail to leave upon the reader’s mind the impression that in the interval between their respective dates of publication, some real progress has been made in meteorology. Perhaps this is most conspicuous in the enlarged ideas that are now entertained concerning the conditions upon which the changes of weather depend. Local weather was first discovered to be contingent upon travelling areas of disturbance, each of which averaged many hundreds of miles in diameter, while, at the present time, the relation of these areas to one another, as parts of a single terrestrial system, has become a prominent topic of inquiry. If meteorology has thus been, to a certain extent, rescued from the ever accumulating chaos of numerical tabulations, which threatened to engulf the whole science, the improvement is mainly due to the development in recent times of the synoptic study of weather over large regions of the earth’s surface, to which so great an impetus has been given by the extended facilities of telegraphic communication. 4. Balloon ascents, with a view to military purposes, are now systematically carried on under the direction of the War Office; and the endeavour has been made to take advantage of these ascents for 84 Anniversary Meeting. [Nov. 30, observations of the thickness of the aérial current which causes our winds, and of the peculiarities of the currents above it in the upper strata of the atmosphere. The military authorities have offered their co-operation in the most cordial manner; but the attention of an aéronaut is often so much engrossed by the operations necessary for working his balloon, that he has but little leisure for taking systematic records. Nevertheless, observations of considerable interest have already been obtained, relating especially to the velocity and direction of the upper air currents ; and there can be no doubt that a continuance of such observations affords the best prospect at present open to us of add- ing to the very scanty knowledge which we possess of the movements of the atmosphere, even at a moderate height above the earth’s surface. Among the various duties which the President of the Royal Society is called upon to fulfil there are those of a Trustee of the British Museum; and, as an operation of great importance to Science, namely the removal of the natural history collections to the new build- ing at South Kensington, is now going on, the Fellows may be in- terested to hear what progress has been made in the work. The plans for the new building were approved as long ago as April, 1868; but the works were not commenced until the early part of 1873. Their progress was retarded by difficulties in the supply of the terra cotta with which the building is faced within and without, and in which the mouldings of arches and other ornamental features are executed. The building was finally handed over to the Trustees in the month of June of the present year. It contains cases for three only of the Departments for which it is intended, namely, Mineralogy, Geology, and Botany; the necessary funds for the Zoological Department not having been yet voted. As the latter collections are equal in bulk to the other three collectively, it follows that half only of the new building can at present be actually occupied. The removal of the collections for which cases had been provided, commenced in the last week of July, and was virtually completed by the end of September. Geology, which was very inadequately displayed in the old build- ing, is now more commodiously accommodated than heretofore. It occupies a gallery 280 feet in length by 52 in breadth, forming the ground floor of the east wing of the new museum, together with eight other galleries covering an area of 200 x 170 feet at the back, and admirably adapted for the exhibition of the specimens. One of these galleries will be devoted to the illustration of stratification. The principal part of the minerals has been moved and replaced in the cases in which they were arranged in the old building. This collection now occupies the first floor of the east wing of the new museum, and the space devoted to it is 280 x 50 feet in area. It is already arranged for exhibition. 1880. ] President's Address. 85 The Botanical collections are placed in the gallery over the minerals, where the space for exhibition and the conveniences for study are much greater than in their old quarters. The construction of the cases for the Zoological specimens, and the ultimate removal of these collections, must depend upon the amount of the Parliamentary vote for the purpose; but under the most favourable conditions it can hardly be hoped that this Department can be open to the public or to students in less than two years from the present time. The ‘‘Index Museum,” designed by Professor Owen, will form a prominent feature in the new museum. The object of it, in his words, is “to show the type characters of the principal groups of organised beings ;’’ and “‘to convey to the great majority of visitors, who are not naturalists, as much information and general notions of its aim as the hall they will first enter and survey could be made to afford.” One of the principal difficulties attending the transfer of the Natural History Departments to a separate building consists in the provision of books for the use of the keepers and their staff, as well as for students who may visit the museum. Hitherto the separate collections of books, known as departmental libraries, supplemented as occasion might require from the main library of the museum, have sufficed for all purposes. But now, when the departmental libraries have to stand by themselves, it is impracticable to carry on even the current work of arrangement without additional resources. For an adequate supply of the necessary works a very large outlay would be required, supposing that the works were in the market. But many of them are out of print and have become scarce; and a large grant of public money would perhaps raise the market price almost in proportion to its magnitude. This being so, it has been thought best, on the whole, by the Govern- ment to make an annual grant to be expended from time to time as favourable opportunities for purchase may offer. If it should prove possible, and on other grounds desirable, to allow the Banks’ Library to follow the collections with which it has always been practically connected, the wants of the Natural History Departments would (so far as books up to the date of its bequeathment are concerned) be in a great measure supplied. Another of the duties which falls officially on your President is to take part in the organisation of technical education as .promoted_by the City and Guilds of London Institute, which is now incorporated under the Companies Acts, 1862-80 as a registered association, and of which the Presidents of the Royal Society, the Chemical Society, the Institute of Civil Engineers, and the Chairman of the Council of the Society of Arts, are members. In the Memorandum and Articles of Association of the Institute, its objects are fully set forth. They may be summarised under the following heads :— MOL, XXXI. H 86 Anniversary Meeting. [ Nov. 30, 1st. The establishment of a central technical institution for instrue- tion in the application of science and art to productive industry. 2nd. The establishment of trade and technical schools m London and in the country. 3rd. The development of technical education by means of examina- tions held at the Central Institution, or at other places. Ath. To assist by means of grants existing institutions in which technical education is being promoted. 5th. To accept gifts, bequests, and endowments, for the purposes of the Institute. The Institute is supported by subscriptions from sixteen of the City Companies, of which the largest contributors are the Mercers, Drapers, Fishmongers, Goldsmiths, and Clothworkers. The Institute has been in active operation not much more than a year, and during the last six months the work of the Institute has developed considerably in each of its several departments. These may be considered under the following heads :— 1. Technical Instruction. 2. Hxaminations in Technology. 3. Assistance to other Institutions. 1. Since November last, courses of lectures and laboratory instruc- tion have been given in the temporary class rooms of the Institute, at the Cowper Street Schools, under the direction of Professor Arm- strong, F.R.S., and of Professor Ayrton. The subjects of instruction have included Inorganic and Organic Chemistry, with special refer- ence to their industrial applications; Fuel, Hlectro-depositions of Metals, and Photographic Chemistry; General Physics, Steam, Hlec- trical Engineering, Electrical Instrument Making, Electric Lighting, Weighing Appliances, and Motor Machinery. During the term ending July last, the number of tickets issued to students, most of whom belonged to the artizan class, exceeded three hundred. A considerable accession of students is expected as soon as the building in Tabernacle Row, the plans of which are already settled, shall be erected. This building, which is estimated to cost £20,000, will provide accommodation for schools of Technical Physics, Technical Chemistry, and Applied Mechanics. Many of the day students at these classes are pupils of the Cowper Street Schools, and it is hoped that, by adapting the course of technical instruction to be given in the College to the wants of these boys, a very complete technical school for the children of artizans will have been established. The evening lectures and laboratory instruction, which are more advanced and more special, are attended very largely by external students, for whom the present temporary necommet is already too limited. | At Kennington, schools have been established in which practical 1880. | President's Address. 87 instruction is given in various art subjects, such as Painting and Drawing, Modelling, Designing, and Wood Engraving. These schools _ are attended by both sexes, and are under the immediate direction of Mr. Sparkes. The numbersin attendance last term were as follows :— Milood Hineraving.). 00). 600s 68.6 8 Students, 3 Men, 5 Women. Merlo MING Wane lteineayoea 5 Rlandemint ts 28 s, ZOE sp NEM ed Drawing and Painting from Life. 42 hy OR Ri Aa Sere PRS MMOL IK. Eis RISA. LR 33 a OI ol we The Central Institution for instruction in the application of the higher branches of science to industrial pursuits is about to be erected on a plot of ground in Exhibition Road, granted by the Commissioners of 1851. The construction of this building, which, when completed, will cost £50,000, has been entrusted to. Mr. Alfred Waterhouse, who is now engaged in the preparation of plans. 2. In the year 1879, the examinations in Technology, which had been initiated by the Society of Arts, were transferred to this Insti- tute. Various changes were introduced into the regulations. New subjects were added, and, in order to stimulate the teaching of Technology throughout the country, the principle of payment to teachers on the results of the examinations was adopted. The en- couragement thus afforded to teachers gave a great impetus to the formation of classes throughout the country in technological subjects. Last year the number of candidates. for examination was 202, while at the recent examination, held in May, 816 candidates presented them- selves, of whom 515 satisfied the Examiners. During the last few months the number of classes throughout the country, in which technical instruction is being given, has considerably increased, and, judging from the returns already received, there is reason to believe that the number of candidates who will present themselves for exami- nation next May will be much greater than in either of the preceding years. The new programme, which is just issued, contains a syllabus of each subject of examination, and every effort has been made, short of testing the candidate’s practical skill, to make the examinations as efficient as possible. To obtain the Institute’s full certificate, each candidate is required to give evidence of having obtained some preli-. minary scientific knowledge. 3. In order to take advantage of efforts that are already being made to advance technical education, the Institute has given sums of money for specific objects to several institutions in which technical instruc- tion is provided. The schools, colleges, and other bodies to which grants have been made by this Institute, are University College and King’s College, London, the School of Art, Wood Carving, and Mining Association of Devon and Cornwall, the Nottingham Trade and H 2 88 Anniversary Meeting. [Nov. 30, Science Schoois, the Artizans’ Institute, the Birkbeck Institute, the Lancashire and Cheshire Union, and the Horological Institute. The Artizans’ Institute gives practical instruction in several of the humbler crafts in which artizans are engaged, such as carpentry, zine work, and plumbers’ work; and corresponds, therefore, to some slight extent, with the apprenticeship schools of the Continent, from which, however, it differs in many important particulars. A similar experiment is being tried at the Horological Institute, where, at the expense of the Guilds, classes have been organised in which appren- tices are practically instructed in the various branches of the watch- making trade. It is found that the demand for technical instruction in London and throughout the provinces is very great, and’the efforts that have been so far made by the City and Guilds of London Institute, have afforded considerable satisfaction to artizans and others engaged in industrial pursuits, and promise, when further extended, to be of the utmost service in the development of technical education in this country. - Turning now more particularly to the progress and the applications of science, I venture to make mention of a few topics which have come under my own observation :— The aspect of spectrum’analysis has become much complicated by two sets of facts. First, the increased dispersion, the improved de- finition, the enlarged electrical power at our command, and, above all, the substitution of photography for eye observations, have revealed to us an almost overwhelming array of lines belonging to each sub- stance. And, secondly, the same means have shown that many sub- stances present different spectra when in different molecular states. These complications have led spectroscopists to seek some relief in theories of simplification. Lecog de Boisbaudran, Stoney, Soret, and others, have suggested that many: of the lines, or groups of lines, may be regarded as the harmonics of a fundamental vibration; and they have shown that in certain cases this view will account for the phe- nomena observed. Professors Liveing and Dewar have contributed largely to our knowledge of the subject, by their observations on the reversed lines, Looking in another direction, Mr. Lockyer considers that in increased temperature we have:the means not only of resolving com- pound bodies into their elements, but even of dissociating bodies hitherto regarded as elementary mto ‘still more simple substances. There still remain serious difficulties connected with Mr. Lockyer’s views; but it is to be hoped that his indefatigable energy will in some way or other ultimately overcome them. The outlying parts of the spectrum, beyond the visible range, must always be a subject of interest; and while MM. Cornu and Mascart, and others, have extended our knowledge of the ultra-violet end, 1880. ] President's Address. 89 Captain Abney has opened out to us a new region beyond the red. Lord Rayleigh and others before him have, however, proved that there must be a limit at the least refrangible end of the spectrum. Professor Stokes, long since, noticed the difference in length between the spectrum of the sun and that of the electric arc; and M. Cornu has recently shown by observations at elevated stations that the great rapidity of atmospheric absorption must preclude the hope of any ereat extension of the solar spectrum toward the more refrangible end. The striking advances made in electricity during the last few years, and marked by, among other things, the inventions of the telephone and the microphone, have been followed by a step not less daring in its conception, nor less successful in its execution ; I allude, of course, to the photophone, the result of the researches of Mr. Graham Bell and Mr. Sumner Tainter. The principle of this instrument is already known. A powerful beam of light is first thrown upon a flexible mirror, the curvature of which is modified through vibrations set up in it by the human voice. The reflected beam is then received by a selenium “cell,” forming part of an electric. circuit. The in- tensity of the light so received, and with it the resistance in the circuit due to the selenium, varies with the varying curvature of the flexible mirror. A large parabolic mirror is used at. the distant station to concentrate the light on the selenium “ cell;”’ and a telephone in the circuit reproduces the variations in the form of sound. Mr. Bell has, however, also shown that rays from the sun, or an electric lamp, when rendered intermittent by any convenient means, will set up in a plate of almost any substance vibrations corresponding to the intermittence. The substances as yet tried are: metals of various kinds, wood, india-rubber, ebonite, and many others, and among them zinc appears to be one of the best suited for the purpose. This result, which is independent of any electric action, is, perhaps, due to heat rather than to lght. In these, as in many other issues of scientific research, we can hardly fail to be impressed by the almost inexhaustible resources which lie ready to hand, if we only knew how to use them, for the interpretation of nature, or for the practical purposes of mankind. During the past year Professor Hughes employed his induction balance for the detection of very minute impurities in small masses of gold. Mr. Preece also has shown how slight increments of temperature in fine wires transmitting telephonic currents of electricity, will suffice to reproduce sonorous vibrations; and even articulate speech at a distant station by their influence on thin platinum wires, only six inches in length. Mr. Stroh has shown that, at the point of contact of two metals carrying strong electric currents, adhesion takes place, varying with 90 Anniversary Meeting. | [Nov. 30, the nature of the surfaces in contact; and that many of the effects at points of contact, previously attributed to induction, may be due to the peculiar action now for the first time brought under notice. It is worthy of record, that two Atlantic cables have been success- fully laid during the present year; but success in cable-Jaying has become so much a matter of course, that its occurrence has attracted little public attention. Two cables, each of more than 500 miles in length, have been laid across the Mediterranean ; and the Cape Colony has been placed in telegraphic communication with this country, by a cable of not less than 4,400 miles. Constant attention is paid in the General Post Office to the intro- duction of improved methods for the furtherance of the telegraphic communication throughout the country. Steady progress has been made in bringing the electric ight into practical use. The illumination of the Albert Dock of the London and St. Katherine’s Dock Company, the Liverpool Street Station of the Great Hastern Railway, the St. Hnoch’s Station of the Glasgow and South-Western Railway, and last, but not least, that of the read- ing room of the British Museum, has become an accomplished fact ; while the city authorities have decided to extend the use of this ight over various thoroughfares under their control. The subdivision of the light for domestic purposes is a problem which appears to have found a solution in the incandescent carbon lamp of Mr. Swan. Beside this, Mr. J. H. Gordon has devised, for the same purpose, a very ingenious application of rapid sparks from alternating machines, — such as that of De Méritens, to produce incandescence in refractory metals. Lamps constructed on this principle completely fulfil the conditions of subdivision, but some difficulties of detail still retard their adoption for general use. There is, however, every reason to hope that the experience already gained, and the intelligence at present brought to bear upon the subject, will before long supply us with more than one form of domestic light. The chief question of interest which has occupied the attention of the Tron and Steel Institute has been the adaptation of the “ basic” pro- cess to the production of steel from pig metal containing a considerable percentage of phosphorus. Hitherto only pure hematite and spathic ironstones have been used for the production of steel; but it has now been shown that, by the employment of basic linings and basic slags, the metal is almost completely cleared of its phosphorus, and that steel of good quality may be produced from inferior ore. The Conference on Lightning Conductors, composed of delegates from the Royal Institute of British Architects, the Society of Telegraph Engineers, the Physical Society, and the Meteorological] Society, is steadily pursuing its labours. A large mass of facts has been accumulated; several leading questions have been decided ; and 1880. | President's Address. 91 it is hoped that, in the course of the coming year, the Report of the Conference will be issued. One of the most interesting, and at the same time useful, applications of the dynamo-machines, is that of transmitting mechanical power to spots, or under circumstances, where the ordinary appliances cannot be conveniently used. Perhaps one of the most remarkable instances of the application of the principle, is that by Dr. Werner Siemens to the propulsion of railway carriages in Berlin. Other applications will doubtless by degrees extend themselves over a wide range of industry; especially in localities where water-power is abundant. Our Fellow, Dr. C. W. Siemens in London, and M. De Méritens in Paris, have demonstrated the use of the high temperature of the electric arc in fusing refractory metals. The method of operation, while peculiarly convenient for laboratory purposes, and for de- monstration, promises to be capable of extension, even to the large demands of commerce and manufacture. I should not, moreover, omit mention of the very beautiful ex- periments by Dr. C. W. Siemens, on the effect of the electric light on the growth of plants, on the opening of flowers, and on the ripen- ing of fruit. On this subject we hope to hear more after the experi- ments which, already commenced, he contemplates continuing during the coming winter. I am not sure how far the fact is known to the Fellows of the Royal Society, that the Society of Telegraph Engineers have thrown open to the scientific world a remarkable collection of books on electrical science, collected by our late Fellow, Sir Francis Ronalds, and be- queathed by him to that Society. The catalogue, compiled by the collector, is a monument of concentrated and well-directed labour. As regards the Transit of Venus in 1874, the printing of the observations is complete for the two groups of stations in the Sand- wich Islands and Egypt, and that for others is in progress. Preparations are already being made with a view to the observation of the Transit of Venus in 1882. As a preliminary step for this operation, as well as for general purposes, it had been decided that the longitude of the Cape Observatory should be definitively deter- mined by telegraphic connexion with Aden, which place is already telegraphically referred to Greenwich; and, notwithstanding a tem- porary interruption on the land line, Cape Town—Durban, it may be hoped that the determination will be effected at no distant period. Mr. Gill is prepared to undertake the main share of the work. With the same objects in view, on the urgent representation of the Astronomer Royal, it has also been determined to connect one of the Australian Observatories with Greenwich, through Madras, the longi- tude of which is well known; and this operation will be very much facilitated by the share which Mr. Todd, Government Astronomer 92 Anniversary Meeting. [Nov. 30, and Superintendent of Telegraphs at Adelaide, would be prepared to take in it under the auspices of his Government. The eastern boundary of the colony having been defined by Imperial Act as the 141st meridian, a wish has been expressed officially for the accurate con- nexion of Adelaide with Greenwich, independently of the Transit of Venus. The Astronomer Royal has explained in detail the preparations which he considers necessary, so far at least as this country is con- cerned, for the effective observation of the transit, and he has introduced several alterations in the plan which he had; formerly suggested. The experience of the transit of 1874 points to the de- sirabihty of sacrificing something in the magnitude of the parallax- factor for the sake of securing a higher elevation of the sun; thus, for retarded ingress, Sir George Airy had at first proposed to refer principally to the coasts of the Canadian Dominion and the United States of North America, where the sun’s elevation is from 15° to 18°; he now proposes to substitute for this the whole chain of West India Islands, from the eastern extremity of Cuba to Barbadoes, or stations on the neighbouring continent of Central America. Bermuda is also included as a favourable point for observation. Most, if not all, of the longitudes required have been determined with great precision by the Hydrographic Department of the United States. For ingress accelerated, Sir George Airy relies entirely upon stations in the Cape Colony. For the accelerated egress, all the stations suggested for ingress retarded will be available. For egress retarded, although the fixed Observatories at Melbourne and Sydney will contribute to the observation of the phenomenon, they will have the sun at a some- what low elevation (10—14°) ; it is therefore proposed to rely mainly upon New Zealand, with which we are in telegraphic communication vid Sydney. Considerable correspondence has taken place on the subject of Australian longitude, and it is expected that the necessary steps to effect the connexion of one of the Observatories, probably Adelaide, with Madras, will be taken early in the ensuing year. Sir G. B. Airy has completed the laborious calculations in his Numerical Lunar Theory, from which the corrections to the co- efficients of Delaunay’s Lunar Theory are to be deduced; and in con- nexion with this work, he has made an investigation of the value of the Moon’s Secular Acceleration, for which he finally obtained the value 5”°477, thus confirming the results obtained by Professor Adams, and subsequently by Mr. Delaunay. On this important question, Professor Adams has also published an investigation. (‘‘ Monthly Notices,” vol. xl, Nos. 411 and 472.) A new determination of the Physical Libration of the Moon from a large number of lunar photographs taken with the De La Rue reflec- tor at the Oxford University Observatory has been recently made by 1880. | Presidents Address. 93 Professor Pritchard, the result being to indicate the existence of a small rotational inequality. Messrs. J. Campbell and Neison have made use of the Greenwich Observations, 1862 to 1876, to determine the Lunar Parallactic Inequality, from which they deduce for the value of the Solar Parallax, 8/778, or 8’""848, according as the existence of a forty-five year inequality, apparently indicated by the observations, is admitted or not (“Monthly Notices,” vol. xl, Nos. 7 and 8). The Sun’s Parallax has also been determined by Mr. Downing, from N.P.D. observations of Mars at Leyden and*Melbourne, in 1877. The value thus found is 8'"96. (‘‘ Astronomische Nachrichten,” No. 2,288.) In continuation of his researches on tidal retardation from the action of a satellite on a viscous planet, Mr. G. H. Darwin has in- vestigated the secular changes in the orbit of a satellite, deducing the early history of the earth and moon from the time when they were initially in contact, each revolving in the same period of from two to four hours. This leads to the suggestion that the moon was produced by the rupture of the primeval planet. In another memoir, Mr. G. H. Darwin gives analytical expressions for the history of a planet and a pmele satellite. (“ Phil. Trans.,’ 1879, ‘‘ Proc. Roy. Soc,” vol. xxx, pp. l, 255.) An important work in connexion with the United States Northern Boundary Commission has been published by Mr. Lewis Boss, on the Declination of Fixed Stars. The systematic corrections to some seventy catalogues have been discussed, and, from the mean of the whole, standard declinations of 500 stars have been deduced. Dr. Gould’s “‘ Uranometria Argentina” and M. Houzeau’s “ Ura- nométrie Générale,” are of especial value as giving important infor- mation on the brightness and distribution of the stars in the southern hemisphere. Interesting results as to the diameters of satellites have been ob- tained by Professor Pickering from photometric observations, on the assumption that their albedos do not differ greatly from those of their respective primaries. (‘‘ Annals Harvard College Observatory,” vol. xi.) He has further investigated, on somewhat similar princi- ples, the dimensions of the fixed stars, with especial reference to binaries and variables of the Algol type. (“ Proc. Amer. Acad.,” vol. xvi.) Professor Pickering has also commenced a photometric survey of the heavens in which the brightness of every star visible to the naked eye is to be determined. He has further undertaken a search for planetary nebule by a new method, in which, by the use of a direct-vision prism in front of the eye-piece, the nebula is at once detected by its monochromatic spectrum, focussing a point of light instead of a coloured line as in the case of a star. About a hundred thousand stars have been examined, and four new planetary nebule 94 Anniversary Meeting. [ Nov. 30, have been detected. (‘‘ American Journal of Science,” October, 1880.) From the grouping of the aphelia of certain periodic comets, Pro- fessor G. Forbes has inferred the existence of two ultra-Neptunian planets, and has indicated their approximate positions. (‘‘ Trans. Roy. Soc., Edinburgh.”) Mr. D. P. Todd has deduced from the per- turbation of Uranus, a position for an ultra-Neptunian planet closely agreeing with that found by Professor G. Forbes. So far, the search for the hypothetical planet with the 26-inch Washington refractor has been unsuccessful. (‘‘ American Journal of Science,’”’ September, 1880.) Professor Bredichin’s researches on the tails of comets have led him to the classification of these appendages according to the value of the solar repulsive force which would have generated them. Having discussed the forms of the tails of thirty-three comets, he finds that they belong to three types, corresponding respectively to repulsive forces 11, 1'4 and 0°3 (the sun’s gravitation being taken as 1), and adopting Zollner’s hypothesis of a repulsive force, due to electricity and inversely proportional to the specific gravity, he infers that the tails of the three types are composed respectively of hydrogen, carbon, and iron. In the case of the second and third types other elements of nearly the same atomic weight may replace or be mixed with the carbon and iron, and in such a comet as Donati’s a number of substances may be mixed in the tail, which will con- sequently spread out in the plane of the orbit. The first type com- posed of hydrogen will always remain separated from the others. (‘‘ Annales de Observatoire de Moscou,” vols. 11i—v1.) The appearance, at the beginning of this year, of a great comet in the southern hemisphere, recalling by the length of its tail and the smallness of its head the remarkable comet of 1845, has excited great interest, more especially as it was found that the orbits of the two comets were sensibly the same. The observations of the comet of 1843, however, do not appear to be compatible with so short a period as thirty-seven years, and Professor Oppolzer has shown that the action of a resisting medium would not meet the case. (‘‘ Astro- nomische Nachrichten,” Nos. 2314, 2515.) Under these circum- stances Professor D. Kirkwood has suggested that the two bodies may be fragments of one original comet, viz., that of 370 B.c., which is said to have separated into two parts like Biela’s comet. (‘* Obser- vatory,” No. 43.) Five other comets (including Faye’s periodical comet) have been discovered this year, but two of them were lost through cloudy weather before a second observation could be made. In astronomical physics Mr. Huggins has obtained photographs of stellar spectra, which establish the existence of a remarkable group of nine bands in the ultra-violet, probably due to hydrogen, and further 1880. | President's Address. 95 lead him to an arrangement of the stars in a continuous series according to the breadth and marginal differences of the typical lines, particularly of the K line. Mr. Lockyer continues his researches on dissociation, as indicated in solar outbursts, and in connexion with this work is engaged on a systematic observation of the spectra of sun-spots. At the request of the Committee on Solar Physics, corresponding obser- vations are being made at Greenwich. From the series of Greenwich photographs of the sun, 1874—1879, the mean heliographic latitude of spots and mean distance from the sun’s equator, have been deduced for each rotation and for each year. (‘Greenwich Spectroscopic and Photographic Results, 1879.)”’ A fine 36-inch silver-on-glass reflector has been recently constructed by Mr. Common, and with this instrument he has obtained photo- graphs of Jupiter, showing the red spot, and of the satellites. (‘‘ Obser- vatory,” No. 34.) At the outset of an undertaking one figures to oneself in imagina- tion what may be done; towards the close of it one sees in actual fact what has been done. In commencing this address I had hoped to say something of the progress of mathematics; before bringing it to a conclusion, I find my space filled and my time exhausted. How far the good intentions of this year may be realised in the next, cannot yet be seen ; .but the difficulties of a task do not always diminish the fascination of making an attempt. On the motion of Mr. Scott Russell, seconded by Mr. Merrifield, it was resolved :—“That the thanks of the Society be returned to the President for his Address, and that he be requested to allow it to be printed.” The President then proceeded to the presentation of the Medals :— The Copley Medal has been awarded to Professor James Joseph Sylvester, F.R.S. -His extensive and profound researches in pure mathematics, especially his contributions to the Theory of Invariants and Covariants, to the Theory of Numbers, and to Modern Geometry, may be regarded as fully establishing Mr. Sylvester’s claim to the award of the Copley Medal. A Royal Medal has been awarded ‘to Professor Joseph Lister, F.R.S. Mr. Lister’s claims to the honour of a Royal Medal are based upon his numerous and valuable contributions to physiological and biological science during the last thirty years. By permission of its author, the Fellow of the Society best qualified, by his own extensive researches on the germ theory, to form a judgment, I quote the following account of Professor Lister’s work and achievements :— 26 Anniversary Meeting. [Nov. 30, “Tn 1836 and 1837 it was proved independently by Cagniard de la Tour and Schwann, that vinous fermentation was due to the growth and multiplication of a microscopic plant. At the same time Schwann described experiments which illustrated and explained the conditions, now well known, by which flesh may be preserved from putrefaction. But Schwann’s researches were overshadowed by the views of accepted authorities, and they continued so up to the publica- tion of Pasteur’s investigations. From this point forward the view gained ground that putrefaction is the work of floating microscopic organisms; and that if air be thoroughly cleansed of its suspended particles, neither its oxygen, nor any other gaseous constituent, is competent to provoke either fermentation or putrefaction. “Condensed into a single sentence, the merit of Mr. Lister consists in the generalisation, to living matter, of the results obtained by Schwann and Pasteur with dead matter. He began with cases of compound fracture and with abscesses. In simple fracture the wound is internal, the uninjured skin forming a protecting envelope. Here nature works the cure after the proper setting of the injured parts. In compound fracture, on the other hand, the wound extends to the surface, where it comes in contact with the air; and here the operator can never be sure that the most consummate skill will not be neutralised by subsequent putrefaction.. “In the earliest of his published communications, Mr. Lister clearly enunciates, and illustrates by cases of a very impressive character, the scientific principles upon which the antiseptic: system rests. He refers to tne researches of Pasteur, and shows. their bearing upon surgery. He points to the representative. fact, then known but un- explained, that when a lung is wounded by a fractured rib, though the blood is copiously mixed with air, no inflammatory disturbance supervenes; while an external wound penetrating the chest, if it remains open, infallibly causes dangerous suppurative pleurisv. In the latter case the blood and serum are decomposed by the micro- scopic progeny of the germs which enter-with the air; in the former case the air is filtered in the bronchial tubes, and all solid particles are arrested. Three years subsequently, this inference of Professor Lister’s was shown to be capable of experimental demonstration. ‘“‘ After enunciating the theoretic views which guided him, he thus expresses himself in his first paper :— ‘«¢ Applying these principles to the treatment of compound fracture ; bearing in mind that it is from the vitality of the atmospheric particles that all the mischief arises, it appears that all that is requisite is to dress the wound with some material capable of killing these septic germs, provided that any substance can be found reliable for this purpose, yet not too potent as a caustic.’ ‘‘This is the thesis to the illustration and defence of which Pro- 1880.] President's Address. 9% fessor Lister has devoted himself for the last thirteen years. His thoughts and practice during this time have been in a state of growth. His insight has been progressive; and the improvement of experi- mental methods founded on that insight incessant. By contributions of a purely scientific character, which stamp their author as an accom- plished experimenter, he has materially augmented our knowledge of the most minute forms of life. The titles of his papers indicate the direction of his labours from time to time; but they give no notion of the difficulties which he has encountered, and successfully overcome. He performs, without dread of evil consequences, the most dangerous operations. He ventures fearlessly.upon treatment which, prior to the introduction of his system, would have been regarded as no less than criminal. In the Glasgow Royal Infirmary, when wards adjacent to his had to be-abandoned, he operated with success in an atmosphere of deadly infectiveness. Vividly realising the character and habits of the ‘invisible enemy ’ with which he has to cope, his precautions are minute and-severe. This demand for exactitude of manipulation has rendered the acceptance of the Antiseptic System slower than it would otherwise have been; but a clear theoretic conception has this value among others: it renders pleasant a minuteness of precaution which would be intolerable were its reasons unknown. “The operative surgeons of our day have raised their art to the highest pitch of efficiency. Their skill and daring are :alike mar- vellous. Mr. Lister urges an extension of this skill from the operation to the subsequent treatment, contending that every surgeon ought to be so convinced of the greatness of the benefits within his reach, as to be induced to devote to the dressing of wounds the same kind of thought and pains which he now devotes to the planning and execu- tion of an operation. His impressive earnestness; his clearness of exposition; his philosophic grasp of the principles on which his practice is founded—above all his demonstrated success—have borne their natural fruit in securing for him the recognition and esteem of the best intellects of the age.” “In a letter addressed to the writer on the 29th of September, 1880, Professor Helmholtz expresses himself thus :— ‘“‘* Professor Lister ist als einer der hervorragendsten Wohlthater der Menschheit zu betrachten, und als eines der glanzendsten Beispiele, wie segensreich scheinbar minutidse und abstruse wissen- schaftliche Untersuchungen, wie die tber die Hrzeugung mikro- skopischer Organismen, werden kénnen, wenn sie von einem Manne von umfassendem geistigem Gesichtskreise aufgenommen werden.’ ”’ “Tn a letter dated October Ist, 1880, Professor Du Bois Reymond writes :— “ pang qsndy, Jo aAtsn[oxo) spuepralq L 6 102 Seine e Pe Re Sei ssovenyrerecreerenececroanessconsnness SUUTgAT 0 0 OZI Cysdeanetanteveaarevnevageauscovasueyducedesunsoddserseeitss? 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SpUOpTAT(T (14 0 G £02 Cece reece ece rare teersereveseensererteeserese qysnoq spuog URI[VIT A kg 0 0 16Z Glelelels\elelolsisisivievele Sheiuiecelaleis el oiaieeniviave\elaletrisieleleleielelelejsinieivicieiel neers coveveses ereteee aoUv [eg OL, ps g p 2 g ‘Spuog worst] uetpeyy OOOOTE ‘PSNUT, JOISSH) OUT, O 9L ILTF OF OE VAs 0 G 6ET eee esecerees eaeereeee oteres eee eeees Perro eeroetonee boheeee ooorvene Oreos eouRleq (79 OT P Ee Oooo eee neeeeoevere Henan nerenes Cee meee tere eee per eaee Coeecereveoee SpueprtATq 0 Tl Ze So yeonGaNn ICNETIgHBECHOTIOO ABAD BOOB an CooteoGnooneroA “" Tepe prog Lg ZOTL GET eerste senna anhababe oounleg Oz, Ds Ti 2 ig? ‘yooyg Avmpresy “quog aod ¢ poopuvieny serpeyy, 09OF ° “PUNT pay haog 9 LI SF ee) a 6 81 zZ mesnereroorovnsmersdg JO esetjop oy Lq e1qe GesehiZ Seer age 2 CUE ae aR Me Muy 2 gre tia ae gras oourpeq “ “fod TEL qequred qv o}ejsq Jo Quey Fo yyy-oug “ 6 SI w COMO verte ererereenreees TCO NOLO UOOODOOOUOUNOHOUOHTDOOOG OdNG0OrT URIMOOAD kg 6 ont w QOUDOOOOUIOOOOUCOOOOOOOOOOOOOCUCINOOAOOCOREICCIOCCI rH eoeerees 6L8T ‘QOUB[R OL (eG Vi AG! fas ‘PUNT atngoaT unwmoo4y Se i) i Trust Funds. 1880.] IT 91 8o8'T# = | eae Sas de ect rr Gunmen aa Re alee oourreg “| 6 0 Tee Cee eee tees teeta sees nese eer eees seer eeerasereteestnsesese “"quag aad & sposuoy urzpodorqoy “PL ‘SCL PIER Fo osveyoung “ | 6 &@ SOLT Yoojg onquoqog yuep 10d Fs Auvdwoy Avayrery | U194JSI AA TJAON PUB UOPUOT OQOO'TF Jo asvyomag 0 0) C/T SOOO OOO OnO OOOO Onn gn nnn gn nnn nnnnnnng nn nnnngnnngnennnnanntnnnnnnn innit? 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SUOT}BUO(T 6 quno00 Vy [erouos+y Ayoroog tesoyy 04 porLoFsuUVAT, kg | 9 9 966 Coe eee renee e vere esse sess enes eee serssessrereeeeeensseseecors (6481) oouRl_eq OL, (OES 3 eS G3 ‘poyturry ‘Cuvdurog puryT TAOMFIT AA OY} Ul soreT[g porpunyyT OMT, ‘sornquogo(, “quop aod F AvMTIVY ULOJSoA\ YIMON puv uopuoT OQOO'LF ‘quay aod Sg sjosuog uvpypodoyoqy OOS TS “DUNT UOLVINpaT aa IT 8. vSEF | L 8 vse De Site Po ne eee ae et eo Il ST Pee Oereeeee quno0D0 Vy [e18t04 Ayo100g qekory 074 pPoLtozsuBry, | OL 21 DA COP dace rea teeasscosererssees ces Dwar cere wees ees eeeeneterons . 6Z81 ‘QoUvleq OL ps | es ep "y¥001g “guop aod g poonpoy “PG ‘st, LhO‘OF ‘pung haypuoyyT eyL Pp SL ISL ee -dTNODO [ero ky91009 qe soy 04 porrojsuvry kg P SI TST Oo 0e cree serrorererrervevesscccseaceserse pert eeeeecreene OS8T ‘spmopratqy OL Yip ae aes eh, "y904Q “quoy aod G MON “POT “SPL Z8L'C# "PUNT 19LpOLP ay, 110 Appropriation of the Government Grant. —[Nov. 30, Account of Grants from the Donation Fund in 1879-80. Professor W. C. Williamson, to aid in continuing his Investigations of the Fossil Plants of the Coal Measures ih a's ies CE oc eae eto erin ene £30 0 0 Dr. Anton Dohrn, to aid in the publication of Mono- graphs on the “Fauna and Flora of the Gulf of Naples, and adjacent parts of the Mediterranean” £100 0 0 £130 0° 0 Account of the appropriation of the sum of £1,000 (the Govern- ment Grant) annually voted by Parliament to the Royal Society, to be employed in aiding the Advancement of Science (continued from Vol. X XIX, p. 440.) 1880. 1. J. N. Lockyer, for continuation of Researches on the Solar SDECUTIM 4. edd Ss 6 Simlele eR ieie veins. eee er eee ek £200 2. Professors Thorpe and Riicker, for continuation of the Comparison of the Air and Mercurial Thermometers .......... 75 3. A. M. Worthington, for Researches on the Tension of Tngquid Surfaces 0. ci. .3 eels) 6 o one Gees 10 4. W.G. Adams and EH. B. Sargeant, for the Determination of the Ratio of the Lateral Contraction to the Longitudinal Hx- tension in a Cylindrical Bar of a Homogeneous: Hlastic Solid subjected to simple Longitudinal Stress ........-....0-+--+ 100 5. W. Crookes, for continuation of Researches on Molecular Physics im High Vacua:’. jf... 04\.).eieioe snc Oe ener 300 6. W. C. Roberts, for assistance in Conducting Researches on the Passage of Molten Metals and Alloys through Capillary BIOS) kw sveles os die Gu G24 ole gate te siete Sho sla eto le re totals cee eae remem 25 7. Professor Rupert J ones, for continnine the Illustration ae Mossil Mntromostraca.’ .. 4%... esc + ese ce eie eters cierto 25 8. G. E. Dobson, for Investigation of the Natural History of the Mammalian Order Insectivora, with the view of publishing as complete a Monograph as possible of this comparatively little studied order of Mammals, in which full descriptions, with the Anatomy and Geographical Distribution of every Species, will DEN PAVEI 6. Le ous aie doje os so weve whale aise eels (oil - 12) eee 50 1880. | Appropriation of the Government Grant. uy iBrowoinutonward. 5... cis 4 os00 sss £785 9. Baron Httingshausen, for the Investigation of the Hocene Flora of Alum Bay, Bournemouth, and other places.......... 50 10. H. A. Schafer, for Payment of an Assistant in continuing his Histological and Embryological Investigations............ 50 li. C. F. Cross, for the cost of a Balance and Materials to be employed in a Research on Rehydration of Metallic Oxides.... 20 £905 Dr. ' Cr. a5 8 Gy hy Sa SSC To Balance on hand, Nov. 30, By Appropriations, as 1879.. : ee ay MeO22. 9° Int above....... - 905 0 O Grant or Treasny 1880 . .. 1,000 0 © | Printing, Postage, orl MUTECEESDM Ge cot cee he eee ba Bon 8) Advertising ..... 414 0 Balance on hand, Te ROC ees Sec ee Malye) £2,027 12 2 £2,027 12 2 Account of Appropriations from the Government Fund of £4,000 made by the Lords of the Committee of Council on Educa- tion, on the recommendation of the Council of the Royal Society. G. J. Symons, for a Computation of the Mean Annual Rainfall at all known Rainfall Stations in the British Isles at which the requisite Data exist («) during the ten years 1867-76 (8) and also during the ten years 1870-79; to thoroughly discuss the same, and to prepare a Monograph thereupon ..............0. £120 R. H. M. Bosanquet, for the cost of an Engine with Clock, Bellows, and other appliances to be employed in the Solution of various Problems in Acoustics, the repetition and examination of Konig’s Experiments, the Determination of Absolute Pitch, and the transformation of Sound into Periodic Electric Currents... 152 Warried torwards s 00 C. R. A. Wright, for continuation of Investigations on the determination of Chemical Affinity in Terms of Electrical Mag- ANTE TUL 04 cvver'st hip yey) 3,31 36 fear ah’ pice re Revs ange ep atE Ree Sa ee e 150 Dr. Dupré, for the cost of Apparatus and Materials in carry- ing out experiments with a Gravimetric Method in estimating extremely small quantities of Carbon, and its application to the Kxamination of Potable, Waters.2i. 222.2 slg cae seen ra) J. H. Collins, for continuation of Chemical, Mineralogical, Microscopical, Stratigraphic Observations on and Investigations of the-Rocks of Cornwall) g..cb taku’. Gesu cee ek pee 30 W.N. Hartley, for continuation of Researches on the Action of Organic Substances on the Ultra-violet Rays of the Spectrum 100 Professor A. H. Church, for continuation of Researches in Plant Chemistry ys suaie ci lie ppeie se wields eine Gees ok eee 50 ca, I2e0 Administrative(Hxpenses).. 32). 4... 3/2).243062- 65 75 1880.] Report of the Kew Committee. 115 Report of the Kew Committee for the Year ending October 31, 1880. The operations at the Kew Observatory in the Old Deer Park, Richmond, Surrey, are controlled by the Kew Committee, which is now constituted as follows: General Sir H. Sabine, K.C.B., Chawman. Mr. De La Rue, Vice-Chairman. Prof. W. G. Adams. Capt. F. Kvans, C.B. Prot. G. C. Foster. Vice-Adm. Sir G. H. Richards. The Harl of Rosse. Mr. R. H. Scott. Lieut.-General W. J. Smythe. Mr. F. Galton. Lieut.-Gen. R. Strachey, C.8.I. lient.-Gen. Sir J. H. Lefroy, | Mr. H. Walker. K.C.M.G. The work at the Observatory may be considered under seven sec- tions :— Ist. Maenetic observations. 2nd. Meteorological observations. 3rd. Solar observations. Ath. Experimental, in connexion with either of the above depart- ments. . 5th. Verification of instruments. 6th. Aid to other Observatories. 7th. Miscellaneous. I. Macneric OBSERVATIONS. No change has been made in the Magnetographs, which have worked continuously during the year. The curves have recently indicated the approach of a more disturbed period than has occurred for some few years, and a magnetic storm of considerable intensity was registered from August 11th to 1oth. Owing to the gradual secular change of declination, the distance between the dots of light upon the cylinder of the magnetometer had become too small for satisfactory registration, and it was found neces- sary to readjust the instrument by a displacement of its zero. From a, similar cause it was also found necessary to readjust the balance of the vertical force magnetometer. The scale values of all the instruments were re-determined in January, in accordance with the usual practice. 116 Report of the Kew Committee. The monthly observations with the absolute instruments have been made regularly, and the results are given in the tables forming Appendix I of this Report. The Sub-Committee, appointed to consider the best means of utilising the records of the magnetographs, as mentioned in the Report for 1878, reported that it was unadvisable, in their opinion, to proceed with the regular tabulation of the curves, and suggested that attention should rather be directed to their comparison with synchro- “nous curves, taken at other magnetic Observatories in different parts of the globe, in order to ascertain whether similar disturbances occur at these several stations, and at what time intervals; with a view to the development of the theory of magnetic disturbance. In order to carry out this scheme, a circular, inviting co-operation on the part of observers provided with magnetographs of the Kew pattern, was issued to the Directors of the followimg Observatories :— Batavia, Bombay, Brussels, Coimbra, Colaba, Lisbon, Mauritius, Melbourne, Potsdam, St. Petersburg (Pawlowsk), San Fernando, Stonyhurst, Utrecht, Vienna, and Zi-Ka-Wei. Replies favourable to the project were received from all those whose instruments were working under satisfactory circumstances. An examination of the records for the year 1879 indicated the month of March as that most suitable for the purpose of the com- parison. Accordingly, a further request for copies of the declination curves for that month was issued, and, in response, they have at present been received from :— Coimbra, Colaba, Lisbon, Melbourne, St. Petersburg, Stonyhurst, Vienna, and Utrecht. The comparison of these magnetic curves has been undertaken by Professor W. Grylls Adams, who has already communicated to the Swansea Meeting of the British Association a preliminary account of the principal facts which have as yet come to light. The discussion, which is still in progress, cannot be completed until data from the more distant stations, as well as the horizontal and vertical force curves from all stations for the same month, have arrived. The Observatory has also received curves from several of the foreign Observatories, showing the variations recorded by their instruments during the progress of the magnetic storm already referred to. By the kindness of Professor G. Carey Foster, some experiments were made at the laboratory of University College, London, with a view to determine whether the magnetisation of dip-needles could be con- veniently effected by means of a coil of wire conveying an electric current, thereby avoiding certain defects due to their magnetisation by bars, after the ordinary method. The results of these experiments proved that the requisite magnetic intensity could be easily imparted in the way referred to. Report of the Kew Committee. a We At the request of Dr. EH. Van Rijckevorsel, observations have been made with dip-needles constructed of nickel, and also with others of steel nickel plated in order to avoid the injurious effects of rust. The nickel plating proved successful; but it was found impossible to impart a sufficient degree of magnetism to the nickel needles to allow of their giving reliable results. The magnetic instruments have been studied, and a knowledge of their manipulation obtained by Dr. Chistoni and Dr. Harris. Information on matters relating to terrestrial magnetism and various data have been supplied to Professor W. G. Adams, Mr. Adie, Pro- fessor Barrett, Messrs. Barker and Son, Mr. Casella, Professor G. C. Foster, Mr. J. E. H. Gordon, Mons. Marié-Davy, Dr. Rijckevorsel, and Professor Balfour Stewart. The following is a summary of the number of magnetic observations made during the year :— Determinations of Horizontal Intensity ........ 25 Dees rs eh oie obo cena ssh aagte ens 164 se Absolute Declination ........ OM, Il. METEOROLOGICAL OBSERVATIONS. The several self-recording instruments for the continuous registra- tion respectively, of atmospheric pressure, temperature, humidity, wind (direction and velocity), and rain have been maintained in regular operation throughout the year. New fume pipes have been fitted over the thermograph and electro- graph to carry off the products of combustion of the gas more efficiently than the old ones, which had become much corroded. The standard eye observations made five times daily, for the con- trol of the automatic records, have been duly registered through the year, together with the additional daily observations at Oh. 45 m. P.M. in connexion with the Washington synchronous system, and at 6h. 45 m. p.m., for the second synchronous system organized by M. Mascart, Directeur du Bureau Central Météorologique, Paris. The tabulation of the meteorological traces has been regularly carried on, and copies of these, as well as of the eye observations, with notes of weather, cloud, and sunshine have been transmitted weekly to the Meteorological Office. The following is a summary of the number of meteorological obser- vations made during the past year :— Readings of standard barometer ........4...... 1934 cs dry and wet thermometers........ 6546 e maximum and minimum thermo- Tee TS Hy Uiues SiguPa is ccseh evan A. alts 2196 VOL. XXXI. K 118 Report of the Kew Committee. Readings of radiation thermometers .......... 848 4 rain and evaporation gauges ...... 1184 Cloud and weather observations .............. 2300 Measurements of barograph curves............ 9477 dry bulb thermograph curves... 9513 wet bulb thermograph curves.. 9405 wind (direction and velocity).. 18940 revooue WUD GUUATES) 56 66050500700> 639 suns lume ciraceSiait ms s-iqieeie-vcleka 2094 In compliance with a request made by the Meteorological Council to the Kew Committee, the Observatories at Aberdeen, Armagh, Falmouth, Glasgow, Oxford (Radcliffe), Stonyhurst, and Valencia, have been visited as usual and their instruments inspected by Mr. Whipple during his vacation. With the concurrence of the Meteorological Council, weekly abstracts of the meteorological results have been regularly forwarded to, and published by ‘‘The Times,” “The Illustrated London News,” and ‘The Torquay Directory,” and meteorological data have been supplied to the editor of “‘Symons’ Monthly Meteorological Magazine,” the Secretary of the Institute of Mining Engineers, Messrs. Anderson, Buchan, Eaton, Greaves, McDonald, Rowland, Wragge, and others. Hlectrograph.— This instrument has been in continuous action through the year. During the severe frost of last winter it was found necessary to heat the water flowing through the discharge pipe by means of a spirit lamp, suspended from the collector. This precaution enabled the records to be maintained throughout the year, with very few in- terruptions due to frost. In August the instrument was dismounted, and a fresh supply of acid placed in the jar, the charge-keeping properties of which had become slightly deteriorated. Some experiments have been made with a view of determining the effect of the interposition of an air condenser between the collector and the electrometer, in reducing the extent and rapidity of the electrical changes registered by the instrument under certain atmo- spheric conditions. ‘These experiments are still in progress. No steps have yet been taken as to the discussion of the seven years’ curves now in store, but suggestions as to the means of dealing with them are under consideration. The self-recording instruments, with their attendant photographic processes and methods of tabulation, have been studied by Professor C. Niven, who has succeeded the late Professor D. Thomson in the charge of the Aberdeen Observatory; by Dr. Chistoni, of the Roman Obser- vatory; and by M. Perrotint, Director of the Nice Observatory. Report of the Kew Committee. 111.8) The spare barograph, thermograph, and Beckley rain gauge, the property of the Meteorological Council, formerly deposited at the Observatory, having been lent by the Council to the Radcliffe Trustees, were set up at their Observatory in Oxford at the beginning of the year. With a view to prevent certain failures occasionally taking place in the photographic system of registration, which are attributed to chemical action in the wax used in the preparation of the paper, it has been considered desirable to introduce in part of the work, by way of experiment, a new process devised by Captain Abney, R.H., F.R.S., in which unwaxed paper is employed. At the request of Admiral Mouchez, Directeur de l’Observatoire National, Paris, a set of copies of the autographic records, together with descriptions of the instruments and other particulars respecting the Observatory, has been forwarded to the Museum recently established in that Institution. I'll. Sonar OBSERVATIONS. The preliminary reductions of the measurements of the Kew solar negatives having been completed in January last, a re-examination of the pictures was made with the object of classifying the spots ac- cording to a scale of figureand magnitude; this being now terminated, Mr. McLaughlin is engaged assisting Mr. Marth in the reduction to heliocentric elements of the pictures from January, 1864, to April, 1872. These operations have all been conducted under ue direction and at the expense of Mr. De La Rue. The eye observations of the sun, after the method of Hofrath Schwabe, as described in the Report for 1872, have been made on 246 days, in order to maintain for the present the continuity of the Kew records of sun-spots. The sun’s surface was observed to be free from spots on 27 of those days. A catalogue of the whole of the solar photographs taken at Kew during a decade 1862 to 1872, has been prepared and forwarded to the Solar Committee of the Science and Art Department. At the request of the Council of the Royal Astronomical Society, the valuable collection of MSS. containing the memorable series of sun-spot observations made by Hofrath Saisvalbs of Dessau, during the years 1825 to 1867, which had been deposited in the Library af the Observatory, the first volumes since 1865, was transferred to the Society’s Library at Burlington House, London. In order, however, to render the collection of sun-spot observations at Kew as complete as possible, and to prevent the total loss of the observations in case of fire, the Committee voted the sum of £90 to defray the cost of making a complete copy of the solar drawings, he 2 120 Report of the Kew Committee. This was accordingly done, and accurate tracings made of every one of Schwabe’s drawings. These were pasted into blank books, and any important notes were transcribed at the same time. The Observatory, therefore, now possesses a complete record of the condition of the sun’s surface, extending from November, 1825, to the present date. The work was performed by the members of the Observatory staff, in extra hours. Transit Observations.—Ninety observations have been made of sun- transits, for the purpose of obtaining correct local time at the Obser- vatory: 102 clock and chronometer comparisons have also been made. Sunshine Recorder.—The Campbell sunshine recorder, described in the Report for 1875, continues in action, and the improved form of the instrument, giving a separate record for every day of the duration of sunshine, has been regularly worked throughout the year, and its curves tabulated. In April last, the new pattern of card-holder, de- vised by Professor Stokes (“‘ Quarterly Journal Met. Soc.,” vol. vi, p-. 83) was substituted for that previously employed, in order that the records produced by the instrument might be in conformity with those obtained from the other stations of the Meteorological Council. Since that date both cards and tabulations have been transmitted regularly to the Meteorological Office, copies, however, being retained in the Observatory for reference. A similar sunshine recorder has been constructed for the Melbourne Observatory, and, after trial and adjustment at Kew, was transmitted together with a set of pattern-cards, through the Crown Agents to Mr. Ellery. TV. ExpertmentaL Work. Winstanley’s Recording Radiograph.—This instrument, designed by Mr. D. Winstanley, as described in ‘‘ Engineering,” vol. xxx, p. 316, for the purpose of registering continuously the amount of radiation from the sky, by mechanical means, upon a sheet of blackened paper, has been erected on the roof of the Observatory since the beginning of August. | Its indications, which were procured for some weeks, showed it to be a much more delicate appliance than the sunshine recorder or the black bulb thermometer, being affected by changes of radiation from the sky, which take place both at might and when the sky is clouded, as well as when the sun is shining. No use has, however, yet been made of its curves, mainly on account of the difficulty of determining a scale value for them. Wind Component Integrator.—This instrument, owing to the causes referred to in last Report, was not kept in action after that date, and in December it was dismounted. It has since been deposited again in ,) Report of the Kew Committee. 121 the Loan Collection of Scientific Apparatus at South Kensington, the costs attendant on its trial at Kew having been defrayed by the Meteo- rological Council. Photo-nephoscope—This instrument is still in the hands of Captain Abney, R.E., but experiments have been made with several other forms of nephoscope, and also with a new cloud-camera, designed by the Superintendent. Exposure of Thermometers—Hxperiments have been continued throughout the year at the Observatory, with the view of determining the relative merits of different patterns of thermometer screens. For this purpose, there have been erected on the lawn a Stevenson’s screen, of the ordinary pattern, and a large wooden cage, containing a Wild’s screen, of the pattern employed in Russia. Hach of these screens contains a dry and a wet bulb thermometer, and a maximum and minimum, all of which are read daily, at 9 a.m. and 9 p.m., their indications being compared with those of the thermograph at the same hours. A third portable metal screen, designed by Mr. De La Rue for use on board Light-ships, which contains a dry bulb thermometer only, is also carried into the open air by the observer, and read at the same time as the fixed instruments. The cost of these experiments is borne by the Meteorological Council. Glycerine Barometer—This instrument, devised and erected by Mr. Jordan, as mentioned in last year’s Report, has been in successful operation throughout the year, and, in compliance with the request of the inventor, has been continuously observed in conjunction with the mercurial barometer five times daily. In April last, with a view to the more complete removal of the minute quantity of air which had adhered te the sides of the tube at the time of filling, and had since risen at intervals into the vacuum, air pressure was applied to the lower surface of the column by means of a force pump, and the glycerine driven up to the top of the tube. The small bubble of air was then expelled through the stoppered aperture, its place being filled by a drop of the glycerine from the cup. A complete description of the instrument, by Mr. Jordan, was read before the Royal Society, on January 22nd, and has been printed in their ‘‘ Proceedings,” vol. xxx, p. 105. As a preparatory step towards the discussion of the observations made with the instrument, Mr. Jordan has computed a table for the reduction of its readings to a temperature of 32° F., the mean coefficient of expansion of glycerine having been determined by Professor A. W. Reinold to be -000303 for 1° F. between 32° and 212°. The value of the glycerine barometer as an instrument of precision cannot be determined until the observa- tions now in process of reduction by Mr. Jordan have been completed. Meanwhile the Committee have decided to continue the periodical readings, and to make several separate series of readings, at frequent 122 Report of the Kew Committee. intervals, during periods of atmospheric disturbance, so as to de- termine its relative degree of sensibility as compared with ordinary mercurial instrumeuts. De La Rue Evaporation Gauge—The Vice-Chairman of the Com- mittee has devised a small evaporation gauge, by means of which the water given off from a continually-wetted sheet of vegetable parch- ment is measured daily. ‘Two of these instruments, constructed by Messrs. Negretti and Zambra, were set up at Kew, and their indications noted every day, at 10 a.m., together with those of a Piché Hvapori- métre, until the end of July, when, at the request of the Meteorological Council, they were transferred to the care of Mr. Shaw, who is at present engaged at Cambridge in an experimental investigation on hygrometry. De La Rue Anemograph.—tThe electrical attachment to this in- strument having been successfully completed after a somewhat lengthy series of experiments, its registrations were discontinued and the instrument was partially dismounted, in order to allow of its vane being used for certain experiments now in progress with regard to the working of air-meters. Air Thermometer.—The construction of the Standard Air Thermo- meter is still delayed, Professors Thorpe and Riicker not having yet com- pleted their comparisons between the mercurial and air thermometers. By the kindness of Professor H. A. Rowland, of the Johns Hopkins University, Baltimore, U.S.A., the Committee has had the oppor- tunity afforded it of comparing with a number of Kew standards, one of the thermometers which Professor Rowland has employed in his researches on the deviation of the mercurial from the air thermometer. The instrument is that—Baudin, No. 6166—which Dr. Joule (‘‘Proc. Amer. Acad. Arts and Sciences, 1880”) com- pared with the instrument he used in his determination of the mechanical equivalent of heat (‘‘ Phil. Trans., 1878”). Professor Rowland has kindly promised to present the Committee with another of his standards, which has been compared with his air thermometer throughout a greater range of scale than the present instrument. « V. VERIFICATION OF INSTRUMENTS. The following magnetic instruments have been verified, and their constants have been determined :— | A Unifilar, by Gibson, for Elliott Brothers. Four Dip-circles, by Casella. A pair of Dipping-needles for Elliott Brothers. Three Dipping-needles for Dr. E. Van Rijckevorsel. Two Magnetograph-needles for M. Decheyrens, Zi-Ka-Wei. An Azimuth Compass for Barker and Son. Report of the Kew Committee. 123 There have also been purchased on commission and verified :-— A Dip-circle for Dr. Mielberg, Tiflis. A Dip-circle for the Russian Expedition to the Mouth of the Lena. Two Magnetograph-needles for Dr. Wild, St. Petersbure. There has been a satisfactory increase in the number of meteoro- logical instruments verified, which was as follows :— WR VROMMELETS SO UANO ALG 5 sad aelecem oc asic 4 4,7 - Ween Gracl Suein@m eo. e ese ces ae 156 RAMU ONC SEAM ton cite) stone, aids 34's chevayaiaie) stele ays iste 21 Mota cow ase ta: 224 Thermometers, ordinary Meteorological ..... 1487 v Standard 22... eee ome 94, a Mroumbatie «2 aac. cee 68 F Clinical ee ease ce foes oe 3638 be Solar radiation oo). ee 57 Motals weap awa tyes, 5344, Besides these, 22 Deep-sea Thermometers have been tested, 14 of which were subjected in the hydraulic press, without injury, to strains exceeding three and a half tons on the square inch, and 165 Thermo- meters have been compared at the freezing-point of mercury, making a total of 5,531 for the year. Duplicate copies of corrections have been supplied in 20 cases. A special set of Standard Thermometers has been constructed for the Bureau International des Poids et Mesures, at Paris. Seventeen Standard Thermometers have also been calibrated and divided, and supplied to societies and individuals during the year. Three Metre Scales have been divided on glass for the University College Laboratory. The following miscellaneous instruments have also been verified :— eA ONTC CONS feos th cscpo: os apy 8 4 St ay oases slane Saale ks « 10 PMICHTOMMC UCTS ses 5.5 chk ous, Worn ot oP, regs A 12 Ese A TT OOS ic as 6s ofhac ick ieh = si ep ea sn (Sys Sh 13 SSH AT TES a Na eR et sl 2 Ps 5 BITRE OC OME MeN la tong, 4c x sia Sens aucgae aes) aeee es as 4 Cahetometer Scales "0. si... ee es oe ae 2 There are at present in the Observatory undergoing verification, 40 Barometers, 50 Thermometers, | Hydrometer, and 2 Anemometers. Anemometer Testing.—The Committee have had before them the question of the desirability of erecting a suitable apparatus for the 124 Report of the Kew Cominittee. testing of Anemometers and Air-meters; but in the opinion of Dr. Rebinson it will be better to postpone its erection for a time. Meanwhile these instruments, temporarily erected on the roof, are compared directly with the Standard Anemograph, and tables ot corrections supplied to reduce their readings to the same scale of velocities as that indicated by the latter instrument. | The experiments made in 1874, and described in the Report for that year, to determine by means of a “steam-circus”’ at the Crystal Palace, the true value of Robinson’s factors for Anemometers at different velocities, are under discussion by Professor G. G. Stokes, F.R.S., and have been found to afford valuable results. A paper, which he intends to communicate on the subject to the Royal Society, is nearly ready. Experiments have been made with one of M. Hagemann’s Anemo- meters (“ Quart. Jour. Met. Soc.,” vol. v, p. 203), designed for use at sea, the results being submitted to the Meteorological Council. A Bridled Anemometer, designed by Mr. F. Galton, has also been tried. The Galton Thermometer-tester has had a new water-heater fitted to it, and has besides undergone thorough repair and renovation. The Winchester Observatory of the Yale College, U.S.A., having recently established a department on the Kew system, for the verification of thermometers, Professor Newton, Secretary of the Institution, visited our Observatory, studied the methods employed for comparing thermometers, and procured copies of the various forms and certificates used in the work. The Sextant-testing apparatus has been improved during the year by the substitution of reticules, photographed on glass, for the glass threads in the focus of the collimators. The latter, by their breakage, rendered frequent re-adjustment of the instrument necessary. Standard Barometers—Numerous comparisons have been made during the year between the two Welsh Standard Barometers, the old Royal Seciety Standard (which it is found cannot without risk of derangement be returned to Burlington House), and Newman, No. 34, the working Standard of the Observatory. Arrangements have been made by means of which the latter may, when desired, be read by the cathetometer, as well as by its own scale, the correct value of which has also been re-determined. VI. ArIp TO OBSERVATORIES. . Waxed Papers, §c., supplied —Waxed paper has been supplied to the following Observatories :— Batavia, Colaba, Glasgow, Lisbon, Montsouris (Paris), Mauritius, Oxford (Radcliffe), and Utrecht. Report of the Kew Committee. 125 Anemograph Sheets have also been sent to the Madras Observatory, and Mauritius, and Blank Forms for the entry of magnetic observations to Professor Young, Princetown, U.S.A. VII. MiscELLANEOUS. Loan Exhibition—With the exception of the Hodgkinson’s Actino- meter and the three instruments mentioned in the 1878 Report, the instruments specified in the Report for 1876 still remain in charge of the Science and Art Department, South Kensington. At the request of the Secretary of the Royal Society several sets of comparisons have been made between the Hodgkinson’s Actinometers, the property of the Royal Society, and a similar instrument sent home from India by Mr. Hennessey, F.R.S., who has observed with it in that country. International Comparison of Standards—The Committee received an application from the Secretaries of the Comité International de Méteorologie inviting them to assist in the suggested scheme of an international comparison of standard barometers, thermometers, and anemometers. ‘Thisidea has since been abandoned, but M. Hooremann, Chef de Service of the Brussels Observatory, has visited Kew, with several standard instruments, in order to make a direct comparison between the Observatories of Brussels and Kew. At the request of Miss Ormerod, F.M.S., experiments were made on the occasion of testing some thermometers at very low temperatures to determine the effect of great cold upon the vitality of certain grubs and insects selected by her for trial. The Superintendent has, with the consent of the Committee, sub- mitted a paper to the Royal Society on ‘The Results of an Inquiry into the Periodicity of Rainfall,” which was printed in the ‘‘ Proceed- mes,’ vol. xxx, p. 200. He has also read a paper before the Meteorological Society ‘‘ On the Rate at which Barometric Changes traverse the British Isles,” published in the “ Quarterly Journal,” vol. vi, p. 136. The Committee, having memorialised the Under Secretary of State for the Colonies with reference to the establishment of an Observatory for magnetical and meteorological purposes at Hong Kong, has been gratified by the receipt of an announcement to the effect that the Governor of Hong Kong has been authorised to propose a vote for the establishment of an Observatory in that colony. Workshop.—The several pieces of Mechanical Apparatus, such as the Whitworth Lathe and Planing Machine, procured by Grants from either the Government Grant Funds or the Donation Fund, for the use of the Kew Observatory, have been kept in thorough order, 126 Report of the Kew Committee. and many of them are in constant, and others in occasional use at the Observatory, but the funds of the Committee do not at present allow of the employment of a mechanical assistant, although one is much needed. Library.—During the year the Library has received, as presents, the publications of 14 English Scientific Societies and Institutions, and 47 Foreign and Colonial Scientific Societies and Institutions. Ventilation Hxperiments. — The Sub-Committee of the Sanitary Institute of Great Britain is still engaged in experiments on the ventilating power of cowls of different form, for which purpose space has been placed at its disposal in the experimental house. In addition to this, the Institute has recently erected a wooden hut with an elevated wooden platform over it in the park, at a sufficient distance from the Observatory to avoid the eddies in the wind caused by it and the adjacent buildings. Observatory and Grounds.—The buildings and grounds have been kept in repair throughout the year, and the rooms in the basement and some of the upper rooms have been painted and whitened by the Board of Works. No action having been taken by-the Commissioners with respect to the footpath across the park, its temporary repair has been carried on at the expense of the Committee. PERSONAL ESTABLISHMENT. The staff employed is as follows :-— G. M. Whipple, B.Sc., Superintendent. T. W. Baker, First Assistant. J. Foster, Verification Department. J. W. Hawkesworth, Tabulation of Meteorological Curves. H. McLaughlin, Solar Computations and care of Accounts. EF. G. Figg, Magnetic Observer. HK. G. Constable, Solar Observations and care of Library. T. Gunter C. Taylor p Yereation Department. H. Clements A. Dawson, Photography. W. Boxall, Office duties. J. Dawson, Messenger and Care-taker. J. Hiller, having been appointed Assistant to the Curator of the Museums in the Royal Gardens, Kew, resigned in December last. Report of the Kew Committee. 197 Visitors—The Observatory has been honoured by the presence, amongst others, of :— Professor Barrett. Mr. Campbell. Dr. C. Chiston1. Rev. J. E. Cross. Captain M. Hépites. Mr. Hartnup. Professor Libbey. Professor Niven. M. Perrotint. Mr. Baden Pritchard. Mr. Stone. M. Steen. Admiral Stopford. 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POOP OO COPE eH OOH HHH OHS DORE HD OEH DED EHH EEHEH EHH OOO OOD PPO O ROO ree Her OOH oro ees ener es OPE HEHEHE SOE OEE EO DORR COOH Hs meer e rose eer DHE Ee eH ees eH OS OH EOD) DOH OEE ESO OED WUT v [On CLIX se COO HEE Oe ree O08 BOOTH SEH OOHSOOH IT HHH OED EHO HEHE EE ESE EOE OHEHEO HOS BLA IHOCA uf junovp syueulvg pwo sjdraoay h.woyoasesq( avart ary dersoqou ae COOP e ee eo EHH EHH HEHEHE HEHEHE HHO Oee 1949WOJOUS BIT PLO jo arg terreeceeceesceororosscerooora OUTTIVdId ILV PUB BDUIOG JO 99}IIUIULOD LVLOS YMOM-UNG LOF OAT BY OM “UAL stoisisoy Sutrk{dop s1of syuow Avg seteerieecerereeeeernereseerereeners STOIZULOULIOU,L, PaCPUBIS jo. aes Coober oeecone eieinesisieisie esse een 7p ‘suvlndg 66 SUOTINITSU] PUB SOT.LOJCALOSAO ss sereserseres QOTT() [BOLGOLOL00} 9 IN) “eee 19deq paxBM jo oes tereeererececcececeeveseserersereos 99% TIOTSSIUIUIOD UO SJUDUINAJSUT LOf JUOTTAK J 66 ‘Ssaa,q UOTIVOYTLO A ‘QO [Bol9O]0.100}0 IA 6c (a3 oe 66 66 6é dWJO [VoLso[010040 66 66 “--gntT JOIsseyg) AJoLO0g [eA G6L-SL81 WOA ooUVV_ OL, “I "JOD.USQV ice) Report of the Kew Committee. 12 APPENDIX I. Magnetic Observations made at the Kew Observatory, Lat. 51° 28' 6" N., Long. 0° 17 15*1 W., for the year October 1879 to September 1880. The observations of Deflection and Vibration given in the annexed Tables were all made with the Collimator Magnet marked K C 1, and the Kew 9-inch Unifilar Magnetometer by Jones. The Declination observations have also been made with the same Magnetometer, Collimator Magnets N D and N E being employed for the purpose. The Dip observations were made with Dip-circle Barrow No. 33, the needles 1 and 2 only being used; these are 34 inches in length. The results of the observations of Deflection and Vibration give the values of the Horizontal Force, which, being combined with the Dip observations, furnish the Vertical and Total Forces. These are expressed in both English and metrical scales—the unit in the first being one foot, one second of mean solar time, and one grain; and in the other one millimetre, one second of time, and one milligramme, the factor for reducing the Hnglish to metric values being 0°46108. By request, the corresponding values in C.G.S. measure are also given. The value of log 7*K employed in the reduction is 1°64365 at tem- perature 60° F. The induction-coefficient 1s 0:000194. The correction of the magnetic power for temperature ¢, to an adopted standard temperature of 35° F. is 0:0001194(¢,—35) +0:000,000,213(¢,—35)’. The true distances between the centres of the deflecting and deflected magnets, when the former is placed at the divisions of the deflection- bar marked 1:0 foot and 1°3 feet, are 1:000075 feet and 1°300097 feet respectively. The times of vibration given in the Table are each derived from the mean of 12 or 14 observations of the time occupied by the magnet in making 100 vibrations, corrections being applied for the torsion-force of the suspension-thread subsequently. No corrections have been made for rate of chronometer or arc of vibration, these being always very small. The value of the constant P, employed in the formula of reduction ee —"), is —0-00109. BX) OX! To In each observation of absolute Declination the instrumental read- ings have been referred to marks made upon the stone obelisk erected 1,250 feet north of the Observatory as a meridian mark, the orientation of which, with respect to the Magnetometer, was determined by the late Mr. Welsh, and has since been carefully verified. The observations have all been made and reduced by Mr. F. G. Figg. 130 Report of the Kew Committee. Observations of Deflection for Absolute Measure of Horizontal Force. 13 30.58 6 59 49 Distances Bs of Tempe- | Observed Log —: Month. G. M. T. Centres of | rature. | Deflection. x Magnets. Mean. 1S79F Gl, Ide sang foot. a mae, @etoneres |)... |) 27) dese each aaeko Bay ley hs 1:3 Se hipaa fate) atl Le! : 230 ,, 1-0 7-0. | 15 33 95) seen | 1°3 am 7 056 | | November......| 25 12 28 p.m. 10 39 °5 15 35 14 13 me re. || S. | 236 , 1:0 4-4 |) 95) 352 a ieee | 13, rae if i) Bll | December......| 22 12 22 p.m. 1:0 41°O 15 35°37 13 ket 7 4 68 eae | DDB). 1-0 43°0 | 15 84 41a eee | an 13 wa 7 1 30 Tommy den coe 2712 25em| 1-0 23°6 | 15 37 10 1°3 ey: 7 2 See 222 , 1-0 93-5. | a5 (37 Te ao eae 13 Sine 7 246 TSN? Banas 24.12 29v.0.) 1-0 492 | 15 35 29 13 Oe 7 4353) 236 ,, 1-0 42-2 | "15 34 498 | Saeoe 13 ane 7 130 MATH cc s.0.s | 2512 26:ear| meedeO 54-8 | 15 33 6 13 ak A ORD |. 230 ,, 1-0 G0e7 | asso) ellie 1:3 aces TO a2ii area ....| 2712 80P.m.| 1-0 Bei) 1s 2 BI 13 aoe lO he an 237 , 1-0 Riel akan ey | 2 ee | 13 a 7 fos May o2....4.>-| 24 W2ps4ean 710 65-6 9. 5 caren 13 ae 659 27 ee Dist Biko 65-0 | 15 30 17) coe 13 wie 6 59 42 Rowe sik. syel| 29) Taedanan laden o 76°3 | 15 29 15 13 ie 6 59 6 ee | PO SeG v7” | 15 2834, eee 13 ae 6 58 48 Hilly eck. <. | 26 22 82 ple MO 71°8 | 15 29 25 1:3 oe Saas | 240) 9 1-0 67-9 | 15 29 42) eee 13 ils 6 59 25 August ........| 23 12 39P.M. 1:0 64:°6 15 32 45 1:3 ik. ree | BG 1-0 68:1) ||. 15 80 deal eee 13 ee 70 8 September......| 28 12 43 P.M. 1:0 63°3 15 32 38 le e@eee | O 25 9 -12900 237 ,, 1-0 67-2 | 15 3118 Report of the Kew Committee. 131 Vibration Observations for Absolute Measure of Horizontal Force. 1879. November: sic. 60... Mecember’........ 1880. JANUATY.....0-00 ebruary~ oc... » Urls te, ocrais seas PACOTEM arate) «ose v's © - IN Meiigersis she ja s/s» s JT? So ae aS ae BEplemper. ....... Go Meum: Tempe- rature. 55°0 58:2 36:9 41:4 39:5 44:3 21:5 23°0 40°7 52°8 70°4 69:1 Time of one Vibration.* secs. 46376 46380 46301 4°6335 46316 4-6292 46285 46298 46359 4°6350 46393 46403 46405 46405 46423 — 4°6418 4°6504 4:64:72 46450 46432 46483 4°6467 46476 46493 Log mX. Mean. 0°31143 0°31150 0°31192 0°31103 0731093 O'31111 0°31067 0°31117 0°31067 031102 0°31018 | 0°30996 Value of m.+ 0°52528 0°52510 0°52539 0°52476 0°52477 0°52437 0°52451 0°52447 | | 052418 | * A vibration is a movement of the magnet from a position of maximum displace- ment on one side of the meridian to a corresponding position on the other side. + m=magnetic moment of vibrating magnet. Report of the Kew Committee. Dip Observations. 132 + ro) ee) Goat iss hi Dip 5 © = 7, North. WSO, | Cl le tate INO yh seam Oct. |28 3: Vem.| 1 67 42:87 ele | 2 42:75 302 59. I) at 42°81 74) XS) oo 2 42°69 Mean 67 42°78 Nov. | 26 3 10p.mM.| 1 67 42°68 Sows 2 41°68 O38 4) wed 42/18 Bal Gig 1 41-62 - Mean ...| 67 42°04 Dec. | 23 3 4P.M.| 1 | 67 42°62 Sil se 42°12 24 3 23 ,, 1 42°56 3 24.7,, || 2 41°75 Mean ...| 67 42°26 1880.|28 3 5p.m.| 1 67 41:87 Jan. SiS. ane 41°37 99 314.,) 1 1 41-00 SH bl Werte 2 41°87 = aaAN aa aC Mean.. _{| 67 41°53 Feb. | 17 3 16P.M 1 67 42°37 320, | 2 4268 16) 8: 104, |) 1 4218 2 ais idle 41°37 23 si leuiy | val 42-00 TR a8 | 41°12 B13) ae deat 41°12 258, | 2 41-50 o7 348 i 1 42-00 826 ls 41-00 Mean 67 41°73 Mar. | 24 2 55p.mM.| 1 67 42:06 254 ,, | 2 41-62 30258, I i 4206 258, | 2 41°31 a3 Re dl 42-12 Br ae 41°18 Mean..|....| 67 41°72 May June July Aug. Sept. 27 3&9 14P.M. 313 14 8 1k: 3 10.) Mean.. 3 14P.M. Oh UTE og 416 ,, Aoi Mean.. |. WCE OG Iba oo 3 40 P.M. a a. 3) 11015, 3130 Mean..|.... 2 58 P.M. 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By error no corrections for height above sea-level were applied to the extreme barometer readings in the Table on page 462. The following values must therefore be substituted for those printed under extreme maximum and extreme minimum respectively. . Inches. Inches. WSiSre October ..2c 2. «25-2, * OUi'SD2 Jn. 05 eo »29'O26 peer NOVEMDE? i. was cece SOAS 2... 29°205 me Decomber estes sss TOUTOOT eens. ' 29 159 1879; - January. 2.2. 20s | SOARTO 22.9 .00% 29°349 an ebruaryesas. saashs pee OOUS2: [visite pe 2S aA Be Marchy hit. Ph i. mie BOIGSS! we kero 295566 POMPE A DTI. sere tenes se, SUBST cj ccucle, oe LOIS a WIEN eo ko baat eocoae SUTEAE “len be nae i578 Me UNC 2c ee «OOOO esas. 2 4OR Peep euliys cit Ses Mine ey ROO LR Geren se ht O05 - ATIPUBEN asec oles. «es Co OIO4Menns, tote) ee ZOAGS September.....5...2 '30°497 J... .5.. 29:297 138 Presents. [ Nov. 18, Presents, November 18, 1880. Transactions. Birmingham :—Philosophical Society. Proceedings. Vol. I. 8vo. Birmingham 1879. The Society. Danzig :—Naturforschende Gesellschaft. Schriften. Neue Folge. Band IV. Heft 4. 8vo. Danzig 1880 (2 copies). The Society. Dublin :—Royal Irish Academy. Transactions. Science, Vol. XXVI. Part 22. Polite Literature, Vol. XXVII. Part 3. Inrish Manuscript Series, Vol I. Part 1. ‘Cunningham Memoirs,” No. 1. 4to. Dublin 1879-80. Proceedings. Science, Series II. Vol. III. No. 4. Polite Literature, Series II. Vol. Il. No. 1. 8vo. Dublin 1879-80. The Academy. London :—Institution of Civil Engineers. Minutes of the Proceed- ings. Vols. LX, LXI. 8vo. London 1880. The Institution. Royal College of Surgeons. Calendar. 8vo. London 1880. The College. University College. Calendar, 1880-81. 8vo. London 1880. The College. Observations and Reports. Calcutta :—Survey of India. General Report on the Operations. 1878-79. folio. Calcutta 1880. The India Office. Dehra Dun :—Great Trigonometrical Survey. Vol. V. The Pen- dulum Operations. 4th. Dehra Dun and Calcutta 1879. (2 copies). The India Office. Greenwich :—Royal Observatory. Observations, 1878. 4to. London 1880. Astronomical Results, 1878. 4to. Magnetical and Meteorological Results, 1878. 4to. London 1880. Spectroscopic and Photographic Results, 1878-79. 4to. Hxtracts from the Introductions, 1878-79. Ato. ' The Astronomer Royal. Journals. Annales des Mines. Tome XVII. Livr. 1 et 2. 8vo. Paris 1880. L’Ecole des Mines. Flora Batava. Aflev. 249, 250. 4to. Leyden. H.M. The King of the Netherlands. Fortschritte der Physik. Jahrg. XX XI. Abth. 1 und 2. 8vo. Berlin 1879-80. Physikalische Gesellschaft. Zoological Record. Vol. XV. 8vo. London 1880. The Hditor. 1880.] Presents. 139 Charles (Michel) Traité de Géométrie Supérieure. 2nd Hdition. 8vo. Paris 1880. The Author. Quaritch (Bernard) General Catalogue of Books. 1880. Mr. Quaritch. Reed (Sir H. J.), F.R.S. Japan. 2 vols. 8vo. London 1880. The Author. Stokes (Prof. G. G.), Sec. R.S. Mathematical and Physical Papers. Vol. I. 8vo. Cambridge 1880. The Syndics of the Cambridge University Press. Presents, November 25, 1880. Transactions. Adelaide :—South Australian Institute. Addresses delivered at the Laying of the Foundation Stone. 8vo. Adelaide 1879. The Board of Governors. Philosophical Society. Transactions and Proceedings. 1878-79. 8vo. Adelaide 1879. The Society. Barnsley :—Midland Institute of Mining, Civil, and Mechanical Hngineers. Transactions. Vol. VII. Part 50. 8vo. Barnsley 1880. The Institute. Bern :—Naturforschende Gesellschaft. Mittheilungen, 1878 und 1879. 8vo. Bern 1879-80. The Society. Boston :—American Academy of Arts and Sciences. Proceedings. Vol. VII N.S. Part 2. 8vo. Boston 1880. The Academy. Society of Natural History. Memoirs. Vol. II. Part 2. No.1; and Vol. III. Part 1. No. 3. 4to. Boston 1872, 1879. Pro- ceedings. Vol. XX. Parts 2 and 3. 8vo. Boston 1879-80. Occasional Papers. III. 8vo. Boston 1880. With map. The Society. London :—Iron and Steel Institute. Journal. 1880. S8vo. London. The Institute. Sanitary Institute of Great Britain. Transactions. Vol I. 8vo. London 1880. The Institute. Statistical Society. Journal. Vol. XLIII. Parts 2 and 3. 8vo. London 1880. The Society. Zoological Society. Proceedings. 1880. Parts 2 and 3. 8vo. London. « The Society. Observations and Reports. Albany :— Geological Survey of the State of New York. Natural History of New York. Vol. V. Part 2. Text and plates. 4to. Albany 1879. The Survey. 140 Presents. | [Nov. 25, Observations and Reports (continued). New York State Museum of Natural History. Annual Rapes (28th to 31st) by the Regents of the University. 8vo. Albany 1878-79. Batavia :—Observatory. Regenwaarnemingen in Nederlandsch- Indié. Jaarg. I. 8vo. Batavia 1880. The Observatory. Brisbane :—Statistics of the Colony of Queensland for 1878. folio. Brisbane 1879. The Registrar-General of Queensland. Colaba :—Observatory. Report on Condition and Proceedings for 1879-80. folio. Bombay 1880. The Observatory. Aitken (William), M.D., F.R.S. The Science and Practice of Medi- cine. Seventh edition. 2 vols. 8vo. London 1880. The Author. Bell (Jacob) and Theophilus Redwood. Historical Sketch of the Progress of Pharmacy in Great Britain. 8vo. London 1880. The Pharmaceutical Society. Briges (T. R. Archer) Flora of Plymouth. 8vo. London 1880. The Author. Fergusson (James) and James Burgess. The Cave Temples of India. Ato. London 1880. The India Office. Gamgee (Arthur), M.D., F.R.S. A Text-book of the Physiological Chemistry of the Animal Body. Vol. I. 8vo. London 1880. The Author. Glaisher (James), F.R.S. Factor Table for the Fifth Million. 4to. London 1880. The Author. Harrison (W. H.) Psychic Facts. 8vo. London 1880. The Hditor. Wheatley (Henry B.) Bookbinding considered as a Fine Art, Mechanical Art, and Manufacture. S8vo. London 1880. The Author. 1880. | Ona Simplified Form of Torsion-Gravimeter. 141 December 9, 1880. THH TREASURER in the Chair. The Presents received were laid on the table, and thanks ordered for them. The Bishop of Limerick and Professor Asa Gray (Foreign Member) were admitted into the Society. The Chairman announced that the President had appointed as Vice- Presidents :— The Treasurer. Mr. W. H. Barlow. Dr. Hirst. Sir James Paget. General Strachey. The following Papers were read :— I. “On a Simplified Form of the Torsion-Gravimeters of Broun and Babinet.” By Major J. HERScHEL, R.E., F.R.S., Deputy Superintendent, Great Trigonometrical Survey of India. Received October 31, 1880. The present communication anticipates one of greater length and extent, which I hope to be enabled to offer for publication in the “Proceedings” of the Society, the subject of which is the gravi- meters mentioned in the above title. In case the account which I there give of these instruments should be delayed, it seems advisable to hasten, if possible, the time when a serviceable gravimeter shall be available to geodesists, by pointing out a method by which the same principle may be embodied in a simpler instrumental shape. It is not necessary for this purpose that a prior knowledge of the existing designs should be presumed. I hope to be able to show all that is essential without drawing upon any source but a moderate know- ledge of physics. Let us imagine a weight, P, suspended by two* parallel lines, flexible, but inelastic, and offering no resistance on their own account to torsion. Let their length be R, and their distance asunder 2r. Also let @ be the angle through which P is turned by some external force. Then it may be shown that the force which P exerts in a * There is no necessary restriction to éwo suspenders. VOL. XXXI. M 142 Major Herschel. Ona Simplified Form of the [Dec. 9, horizontal direction, tending to cause it to return to its position of rest, may be expressed by Ie. zon 6 = 4/126 vesino exerted at a distance r from the axis of motion. When -- is small, rersin @ this may be represented by the simple function Pa sin @, which varies directly as the sine of the angle of detortion, being 0 at zero and 180°, and a maximum at 90°. This is the ordinary law of torsion of a bifilar balance, in which the suspending lines are regarded as non-resisting. Now suppose the weight P held fast at its position of rest while the upper ends of the suspending lines, no longer impotent, but endued with elasticity and a consequent power of resistance to torsion, are turned, severally, about their own individual axes, through an angle y. ‘The force which will be thereby developed, in what we may now call the wires, will be a true “torsion” force. And, if I am not mistaken, it will vary directly as the angle of torsion, and inversely as the length of the wire, but not as the tension nor as the distance of the wires from each other. Let T be what I may call the factor of torsion, for the particular quality of wire in use. By this 1 mean the force, measured in grains (provisionally), which, exerted at a distance unity (an inches) from the axis, will balance the tendency of the wire, when twisted through one turn to each unit of length, to untwist. Then, under the actual circumstances, the torsion of the pair will be expressed by Qn . a ae ; 2m. which must be divided by r to denote its power, applied at the ends of the wires, to turn the system. Now, let P be released, so that this torsion may act upon it. Let 7=0+9; then ¢ will take the place of 7 in the last expression, and the forces in opposition will be Tsing, and = ; ay and 6 will obviously increase and @ decrease until there is equilibrium. Hence the approximate statical equation of the torsion-balance Pr sin pa Td, Tr or sin 9= Ag. satel 1880. ] Torsion-Gravimeters of Broun and Babinet. 145 Here A is an instrumental constant, which defines the relation of the parts 0, ¢, of the whole angle 7. As 7 increases, 0 @ increase in the dork proportion rh 6. Suppose a point reached where ¢ ceases to increase: then = cos 0=0, and @=90°. At this point, any increase of 7 is wholly absorbed by @; which is easily understood, because at this point the bifilar opposition to torsion is at its maximum. Next, suppose 7 to be further increased, until the rate of decrease of ¢ equals the rate of increase of 0; in other words, to the utmost consist- ent with the relation between these components. At this point, Se cos #)=—1, or cos@,=—A. At this point, too, 6 d can vary reciprocally without affecting 7. It is a position which can only incorrectly be described as one of unstable equilibrium; for though the weight would not return if moved forward, but on the contrary, would continue to move forward, under the pressure of torsion; yet, if moved backward, it would seek to return. It is therefore stable on one side, and unstable on the other. It is easy to test this practically. I have done so, and recognise, in the peculiar conditions, such as are well suited to afford an exact determination ; as I will explain presently. But there are one or two theoretical points to be first noticed. Since cos 9) = — A, it follows that ¢)= —tan 6); that A must be made not greater than unity ; and that 6) must le between 90° and 180°. The condition that P must be Sit is an important one. When- aly ever this is the case, there must be a value of 9, at which the peculiar equilibrium will occur. The condition may be fulfilled in a way to make the position unsuitable for exact observation, but it nevertheless exists; whereas, if P is too small, there is no such position. Transposing, we see that— 1h 1 7 must be >2 . = 7 Tk from which it follows that whatever be the strength of the wires, or quantity of the weight, it is always possible, by modifying the distances between the former, to secure the necessary condition. — From this point of view, too, it appears that the length of the wires is immaterial. The opposing forces are equally affected by a change of length. The magnitude of R therefrom has nothing to do with the equilibrium. Let us now work outa case. I find that a piece of pianoforte wire, 0-03 inch diameter, will carry 100 lbs.; will bear, without apparent M 2 144 Major Herschel. Ona Simplified Form of the [Dec. 9, alteration, being twisted once in 6 inches; and has a factor of torsion equal to 23,700 ers. ar Suppese we decide to use a weight of 200 Ibs., so that T 23,400 wan 1 1 Bes Ree ly. Then rv? must be greater than —, or r >— P 1,400,000 59°” ; or A inch. This is so small a limit, that it affords no guide to the best value to give to r. Again, since @= — tan 0= —see 9 V1 —cos? 0 = 5F aes JI — A2=59rr2 yay nearl == A == 7 @ y> it is clear that 7 must be small, otherwise ¢ would be large, and this would demand a great leneth of wire. We may, indeed, put R62 TT as the least allowable, and this at once gives R=177 1, at least. It seems therefore that we must estimate R first. Let us take 3 feet or 6 6 inches. This gives r< ae ae <'45 inch. A smaller value We would give a lower pitch to the twist, which is very desirable. We may therefore take r=—0°'4 inch. Whence 6=597 x ‘16, in terms of radius, or =" x'16=4°7 revolutions. Finally, tand=—@, and a oon nearly. We may sum up the results, so far, as follows:—A weight of 200 Ibs., suspended by two 0°03 inch steel wires, 36 inches in length, parallel at four-fifths of an inch apart, will be in unstable equilibrium at 92° from its normal position, when the upper ends of the wires have each been turned about their own centres through 4 revolutions 250° +92°, or 4 revolutions 342°, from the same normal position. In this condition any addition to the weight will‘tend to strengthen the equilibrium, while, on the contrary, any relief of weight will throw the system over the summit and set it off, allowing it to expend the torsion in twisting the two wires together. I will now show how this arrangement may be adapted as a gravi- meter, not so much aiming at a description of a finished instrument as at a sketch of something which will fully illustrate what a more perfect design would fulfil. A piece of wire, of the kind described, 7 feet long, is to be twisted upon itself, without straining, giving it ten full turns of torsion, and the ends are then to be secured to each other. This can easily be done so as to give it no chance of relieving itself otherwise than by set, a term which I understand to be the tecknical one in this connexion, meaning that change which takes place in a wire when it is super- torted or overturned beyond what its elasticity will bear. A wire so ~ 1880.] Torsion-Gravimeters of Broun and Balinet. 145 tied up should retain its torsion indefinitely. The force thus per- manently stored represents the constant force against which gravity is to be measured. - To use it, I imagine the ends of the double or twisted cord clamped in two frames of suitable make. The upper one grasps the junction, the lower one the bight. The wires issue from the jaws of the clamps at 0°8 inch from each other. The upper clamp is attached to a support capable of sustaining, without shake, the intended weight of 200 lbs. The lower is attached to the weight so as to have as little loose motion as may be, but so as also to be easily detached for trans- port. Before detaching it the wires should be allowed to twist upon each other. They would then be placed, with their clamps, in a box specially prepared to guard them from all imaginable injury. There would be an arrangement above by which, when attached, the upper clamp would be raised slowly, so as to take up the weight ; which would be turned without rising as the wires untwisted, until finally, it would hang; the wires then being in a state of torsion, the lower ends in a different vertical plane from the upper, according to the weight. I assume that on thus commencing the weight is in excess, so that the angle between the two planes (which will be the @ of the theory) will be about 90°. In this condition we want means of relieving the suspension of so much of the weight as will allow the mass to reach the position of unstable equilibrium, and of determining exactly how much. This I propose to effect as follows :— The weight is to consist of a cylindrical drum, capable of holding 3 cubic feet of water. Near the bottom it will have a smal! stop- cock. When the apparatus is in repose, the cock is to be turned. The flow of water will relieve the weight, the drum will slowly turn, under the solicitation of the wires. If allowed to run freely it can be shut off when the critical point has been passed. This is the first approximation. A little water is put back, and now the cock is turned so as to reduce the flow to drops only. The effect can be watched with a microscope. The flow can at any time be stopped or accelerated. Experience will enable this determination to be made with a degree of precision which it is impossible to over-estimate. The drum should be as light as possible, and silvered inside or pla- tinised. The object is to secure a minimum of friction. As the critical point is approached the force is so small that it would take long to move the whole mass if solid; and if the whole mass were in motion its momentum would be troublesome. For the same reason the obser- vation cannot be made until the body of water is at rest. The same drum will serve for all. weights, and makes it possible to obtain a series of results with different pairs of wires—all prepared in the same way, but of different torsions and widths apart. 146 On a Simplified Form of Torsion-Gravimeter. _[ Dec. 9, Finally, the desired result will depend on the weights. I consider that to weigh accurately even a large body of water is a thing that can certainly be done, but how to do it forms no part of my present design. The drum might conveniently be constructed with a false bottom, the real bottom of the water space being conical, with the stopcock at the apex. By an easy arrangement the closing of the cock might be effected as a consequence of the critical point of unstable equilibrium being reached and passed, the swing being checked by a stop pressing on the cock and shutting it off. Being thus self-acting, the flow might be made as slow as desired, with the certainty of the proper result being _ reached without further attention. The quantity of water remaining could then be measured at leisure. The change of gravity which would cause a change of rate of one second per diem in a seconds pendulum is z34,55 part. Ona weight of 200 lbs., or 1,400,000 grs., this would be 32°4 grs., or rather more than half a fluid dram. I am, of course, quite aware that the efficiency of such a gravimeter depends ultimately on the constancy of the torsion. This is a sine qua non im any gravimeter on the torsion principle, and I assume it to exist. Jf it does not exist, no gravimeter on this principle can be successful. Nor am I regardless that this, and all other gravimeters depending on elasticity, are at the mercy of temperature. But however impossible it may be to command a definite and uniform temperature wherever such an instrument may be instated for observation of the change of gravity, the converse is possible enough: the constancy of gravity can be guaranteed* while observations are instituted for determining the effect of thermometric change. So that if insufficient knowledge of the variation of elasticity with temperature debars such an instrument from being used asa gravimeter, it may with the more reason be looked to to increase that knowledge. It seems only necessary to add that the mode of utilising the fact of a position of unstable equilibrium existing, if desired, between 0=90° and 8=180°, as here indicated, may be open to objection without pre- venting that fact beg capable of utilisation in some better way. The need of a statical gravimeter is so great that I hope what I have said may draw attention to the subject by showing how very simple it really is. Under correction, I would hazard the assertion that there is no instrument which would command a more immediate field of useful- ness than a simply constructed gravimeter, and I think I have shown that it is possible to construct one. * The contrary at any rate is, at the most, suspected more or less strongly, by a few. 1880.] Note on some Fossil Wood from the Mackenzie River. 147 II. “ Note on the Microscopic Examination of some Fossil Wood from the Mackenzie River.” By C. ScHROTER, Assistant at the Botanical Laboratory of the Polytechnic Institution, Ziirich. Communicated by Ropert H. Scott, F.R.S. Re ceived October 22, 1880. In the summer of 1880, Professor Oswald Heer transmitted to me seven specimens of fossilized wood from the Miocene beds of the Mackenzie River for microscopical examination, and, if possible, de- termination of the species, &c. Professor Heer’s determination of the leaves and other remains of the flora of the locality in question have already appeared in the ‘“‘ Proc. Roy. Soc.,’” vol. 80, p. 560, having been communicated to the Society at the end of the last session. The following are the species which I have been able to de- termine :-— 1. Sequoia Canadensis, Schroter n. sp. (Specimens | and 2).*—This wood is very well preserved. (It belongs to the group Cupressoxylon of Kraus.) Its anatomy shows a great resemblance to that of Sequoia gigantea. ‘The principal differences are the following :— (a.) In the cells of the medullary rays of S. Canadensis, the radial pores are always arranged in one horizontal row, whilst S. gigantea has two rows of pores in the extreme ranges of cells. (8.) The number of superposed ranges of cells in the medullary rays in 8. Canadensis is 76. In S. gigantea it is only 55. The differences between S. Canadensis and S. sempervirens are ereater than those between the former and S. gigantea, so that S. Cana- densis cannot belong to S. Langsdorfii, which occurs at the same locality, and which is the Tertiary ancestor of S. sempervirens. It is, therefore, probable that the wood which I have examined belongs to one of the other Tertiary species of Sequoia (perhaps S. Sternbergit, which approaches very closely S. gigantea). Until this identity 1s established I designate it provisionally as S. Canadensis. 2. Ginkgo spec. (Specimens 4 to 7.) Although not so well pre- served as the preceding instances of wood, these specimens are easily recognisable as belonging to the genus Ginkgo by their very charac- teristic medullary rays. Perhaps they should be placed under the species’ G. adiantoides, Ung., which is the commonest of Tertiary Ginkgos, and has been found in Saghalien and in Greenland, between which two localities the Mackenzie River lies. 3. Platanus aceroides, Gp. (Specimen No. 2.) A dicotyledonous * All the specimens referred to in this paper are to be deposited in the British Museum. 148 Dy. Hopkinson. Electrostatic Capacity of Glass. [Dec. 9, wood, which in the arrangement of its vessels and medullary rays resembles so closely the genus Platanus that it most probably is P. aceroides, which occurs at Mackenzie River in the leaf beds. More complete details of my investigation will be found in my paper on the ‘“ Fossil Woods of the Arctic Regions,” in the forth- coming volume (VI) of the “ Flora Fossilis Arctica,” by Professor Heer. II. “ The Electrostatic Capacity of Glass.” By J. HOPKINSON, M.A., D.Sc., F.R.S. Reeerved November 3, 1880. (Abstract. ) In 1877 I had the honour of presenting to the Royal Society* the results of some determinations of specific inductive capacity of olasses, the results being obtained with comparatively low electro- motive forces, and with periods of charge and discharge of sensible duration. In 1878 Mr. Gordon; presented to the Royal Society results of experiments, some of them upon precisely similar glasses, by a quite different method with much greater electromotive forces, and with very short times of charge and discharge. Mr. Gordon’s results and mine differ to an extent which mere errors of observation cannot account for. Thus, for double extra dense flint glass I gave 10'l, Mr. Gordon 31, and subsequently 3°89.{ These results indicate one of three things, either my method is radically bad, Mr. Gordon’s method is bad, or there are some physical facts not yet investigated which would account for the difference. Two possible explanations ‘have been suggested : Ist, possibly for glass K is not a constant, but is a function of the electromotive force. 2nd. When a glass condenser is discharged for any finite time, a part of the residual discharge will be included with the instantaneous discharge, and the greater the time the greater the error so caused. To test the first I measured the capacity of thick glass plates with differences of potential ranging from 10 to 500 volts, and also of thin glass flasks between similar limits ; the result is that I cannot say that the capacity is either greater or less where the electromotive force is 5,000 volts per millimetre than where it is 4 volt per millimetre. The easiest way to test the second hypothesis is to ascertain how nearly a glass flask can be discharged in an exceedingly short time. A flask of light flint glass was tested ; it was charged for some seconds, discharged for a time not greater than ;7355 second, and the residual charge observed so soon as the - SP hil trans: 2 Sree plas + “Phil. Trans.,” 1879, p. 417. t “Report of British Association,’ 1873. 1880.] On the Cochlea of the Ornithorhynchus platypus. 149 electrometer needle came to rest; the result was that the residual charge under these circumstances did not exceed 3 per cent. of the original charge, also that it mattered not whether the discharge lasted =7to5 Second or =, second. These experiments suffice to show that neither of the above suppositions accounts for the facts. I have repeated my own experiments with the guard ring condenser, but with a more powerful battery, and with a new key which differs from the old one inasmuch as immediately after the condensers are connected to the electrometer they are separated from it. In no case do I obtain results differing much from those I had previously pub- lished. Lastly, a rough model of the five plate induction balance used by Mr. Gordon was constructed, but arranged so that the distances of the plates could be varied within wide limits. So far as instrumental means at hand admitted, Mr. Gordon’s method was used. A plate of double extra dense flint and a plate of brass were tried. In the first, by varying the distances of the five plates, values of K were obtained ranging from 1} to 84, with the latter values from ~,to3. It is clear that the five plate induction balance thus arranged cannot give reliable results. The explanation of the anomaly, then, is that the deviation from uniformity of field in Mr. Gordon’s apparatus causes errors greater than anyone would suspect without actual trial. It is probable that the supposed change of electrostatic capacity with time may be accounted for in the same way. IV. “The Cochlea of the Ornithorhynchus platypus compared with that of ordinary Mammals and of Birds.” By URBAN PRITCHARD, M.D., F.R.C.8., Aural Surgeon of King’s College Hospital. Received November 9, 1880. Commu- nivated by Professor HUXLEY, Sec. R.S. (Abstract.) General Form of the Cochlea of the Duckbill or Ornithorhynchus. This cochlea consists of a somewhat curved tube, about a quarter of an inch (6°3 millims.) in length, and one-twentieth of an inch (1°26 millim.) in diameter, projecting forwards from the cavity of the vesti- bule and embedded in the substance of the petrous bone. It is nearly horizontal, and is slightly curved outwards. In section the tube is first oblong, with its greatest diameter from top to bottom, then somewhat triangular, and finally oval, with its greatest diameter from side to side. It terminates in a slightly enlarged rounded extremity, flattened from top to bottom. 150 Dr. U. Pritchard. 3 [Deerg; Comparison with Typical Mammals and Birds. In general form the duckbill’s cochlea closely resembles that of the bird, and is very different to the spiral cochlea of the ordinary mammal. The two first differ, however, in that the duckbill’s is yaore curved, and curved outwards instead of inwards, as in the bird. The enlarged apex of the former is rounded, that of the bird oval. The typical mammalian cochlea tube differs from that of the duckbill, in being spiral instead of merely curved, in tapering from commence- ment to apex, and in being much longer. Lastly, the axis of the spiral cochlea is horizontal, whereas that of the curved one is vertical. The Internal Arrangement and Minute Structure of the Duckbill’s Cochlea. The interior of the tube is divided horizontally into two scale by a partition, the inner portion of which is thick and bony (lamina ossea) ; the outer, thin and membranous (lamina membranacea); a third scala is formed by a delicate membrane (membrane of Reissner) proceeding from the upper surface of the lamina ossea to the inner* wall of the tube. The upper and larger division is the scala vestibuli, and this com- municates posteriorly with the vestibule; the lower is the scala tympani. These two are united at the apex of the cochlea by means of an oval opening, helicotrema. The third, a small triangular tube, is the ductus cochlez, or scala media, and this constitutes the membranous labyrinth ; it contains the endolymph, and is entirely separate from the other two scale, which contain the epilymph. The ductus cochlex is lined with epithelium; the scale vestibul and tympani with endothelium. The lamina ossea is a wedge-shaped mass of modified bone attached to the lower part of the outer wall and the outer part of the floor of the tube. Its inner free margin presents a deep groove (marginal suleus), the lower lip of which projects further inwards than the upper. The lamina ossea does not extend to the apex of the cochlea, and thus allows of the communication between the scale vestibuli and tympani. The ductus cochlez is triangular in section, the floor is formed by the inner portion (limbus) of the lamina ossea and a strong membrane (membrana basilaris), which stretches from the lower lip of the suleus to a mass of connective tissue (ligamentum cuchlez) adherent to the inner wall of the cochlea. The inner wall of the ductus is formed of this ligamentum cochlez ; and the outer wall, or sloping roof, by the delicate membrane of Reissner, which springs from the upper surface * In describing the position of the parts in the duckbill’s cochlea, the median line of the body is taken as the centre ; in the spiral cochlea, the modiolus or axis. 1880.] On the Cochlea of the Ornithorhynchus platypus. 151 of the limbus, and is attached to the upper part of the ligamentum cochlee. The membrana basilaris is composed of three fibrous layers; the lower, longitudinal; the middle, transverse ; and the upper, formed of very fine transverse fibres. There are two blood-vessels running longi- tudinally in the lower layer. The ligamentum cochlez is a somewhat triangular mass of con- nective tissue with numerous blood-vessels, which in its upper portion run longitudinally, and, with the epithelium, form the stria vascularis. The membrane of Reissner is composed of a delicate basement membrane, with the endothelium of the scala vestibuli on its upper surface, and epithelium on its under surface; here and there blood- vessels may be traced on it, running from the limbus to the ligament, and in some places these vessels form convoluted knots. The epithelium lning the ductus cochlez varies according to its position: that lining the membrane of Reissner is composed of a single layer of hexagonal cells; in the sulcus they are rounded ; on the inner part of the membrana basilaris and the lower portion of the ligament they are cuboid; on the upper part of the ligament they are very pecular, and resemble the transitional variety closely packed together. In the deeper part of the layer run numerous longitudinal blood-vessels, and this forms the already mentioned stria vascularis. The remaining portion of the epithelial layer that lies on the lower lip of the sulcus, and on the outer portion of the membrana basilaris, is developed into the so-called organ of Corti. This organ of Corti consists of a double row of rods (of Corti), united at their upper ends and separate below; they stand on the membrana basilaris, and with it form a triangular tunnel. The rods of both rows have cylindrical shafts and enlarged ex- tremities; the upper ends of the inner row are rounded, and fit in corresponding concavities of the outer row. A delicate process pro- jects inwards from the upper part of each of the rods, the processes of the outer ones lying above those of the inner. Rows of hair cells are arranged on either side of these rods—one* to the outer side and three to the inner. Below the three inner rows are situated rows of nuclear cells (cells with well-marked nuclei, but no regular cell-wall), the cells of Deiters. Lying on the lower lip of the sulcus is a small mass of nuclear cells, and there is a row of these cells at each of the lower angles of the triangular tunnel. The inner and outer side of the organ of Corti is formed of modified columnar cells. A reticulate membrane covers the rods and hair cells, the hairs of which project through certain circular meshes of the membrane. * Since presenting this communication I have discovered a second row of hair cells in this position. P52 Dr. U. Pritchard. (Deen; Covering the limbus, crossing the sulcus, and covering the organ, is a mucoid layer, the membrana tectoria. Nerve filaments pierce the upper lip of the sulcus and pass to the hair cells and nuclear cells of the organ. The organ of Corti, with the membrana basilaris below and the membrana tectoria above, form the lamina membranacea. The ductus cochlezee commences as a delicate tube, no doubt con- nected in some way with the saccule of the vestibule. Its termination is very peculiar; instead of ending with the lamina ossea, where the organ of Corti ends, it is continued round the apex of the cochlea to form three-fourths of a circle. Just past the end of the lamina it forms a circular tube; at the other side of the apex, it enlarges into an oval chamber (lagena) which terminates at the base of the lamina ossea. This lagena is lined by epithelium, chiefly cuboid, but with one large patch of nerve epithelium, like the thorn cells and bristle cells found in the macule acustice of the vestibule. (‘‘Quar. Jour. of Micros. Science,” p. 379, 1876.) The cochlear branch of the auditory nerve passes through the bone on a level with the floor of the tube, but to its outer side. It gives off lateral branches all along to the lamina, and its terminal fibres go to the lagena. The lateral branches pass through a ganglionic mass, similar to the ganglion spirale, and then on through the lamina, close to its lower surface, finally perforating the upper lip of the sulcus by a single row of holes (habenula perforata) and entering the organ of Corti as already described. Comparison of the Minute Structure of the Cochlea of the Duckbill with that of Typical Mammals. From the foregoing description, the duckbill’s cochlea is shown to be so unmistakably mammalian in type, that merely the differences will here be noted. The lamina spiralis membranacea increases in width, and so do its component parts, from base to apex of the spiral cochlea; in the duckbill’s this widening takes place, but not nearly to such an extent as in the spiral cochlea. The rods of Corti in the duckbill are not so well developed as in the typical mammal. The membrane of Reissner in this monotreme presents blood-vessels on its surface with convoluted knots; these I have never found nor read of in this situation in any other mammal. The vas spirale of the ordinary mammal is represented by two vessels in the duckhill. The course of the cochlear nerve necessarily differs in the two forms of cochlea. But the great difference is found in the presence of the lagena at the 1880.] On the Cochlea of the Ornithorhynchus platypus. 153 end of the duckbill’s ductus cochlesw; this has never been found in mammals, but is found in birds, reptiles, and amphibians. Comparison with the Bird. A brief description of the bird’s cochlea, will be found in my paper, in extenso ; in this abstract I propose only noting the similarities and dissimilarities. The scale tympani in each type of cochlea correspond. There is no scala vestibuli in the bird, the scala media (ductus) occupying the whole of the upper division of the tube. The membrane of Reissner and stria vascularis 1s represented by the tegumentum in the bird. The lamina ossea corresponds to the quadrilateral cartilage, and the ligamentum cochlee to the triangular cartilage of the bird. There are no rods of Corti in the bird: the hair cells are more numerous and their component hairs are united together into a spine. The nerve fibres pierce the quadrilateral cartilage by numerous rows of holes, instead of one row, as in the duckbill and other mam- mals. The lagena, with its macula acustica, is found both in the bird and duckbill, but in the former is a direct continuation of the ductus, whereas in the latter it is connected by means of a constricted tube. Moreover, the ductus of the duckbill makes three-fourths of a turn, but that of the bird is nearly straight. ‘General Conclusions arrived at by the Research. Although the outer form of this monotreme’s cochlea resembles that of the bird in being nearly straight, yet its internal arrangement is decidedly mammalian. The general acoustic apparatus of the duckbill’s cochlea is not nearly so extensive as that of the ordinary mammal nor is its organ of Corti so well developed. Lastly, the duckbill’s cochlea possesses an addition, the lagena, which is not found in any other mammal, but which is found in the bird, reptile, andamphibian. Thus it presents a distinct link between the cochlea of the higher mammals and that of the lower vertebrates. In conclusion, I desire to give my most hearty thanks to the many Australian friends who, by their zeal in my cause, have provided me with specimens of the ornithorhynchus in such a good state of preservation as to allow of their microscopic preparation and examination. 154 Mr. J. B. N. Hennessey. [ Dec. 16, - December 16, 1880. THE PRESIDENT, followed by Dr. C. W. SIEMENS, in the Chair. The Presents received were laid on the table, and thanks ordered for them. The following Papers were read :— I. “On Actinometrical Observations, made in India at Mus- sooree and Dehra in October and November, 1879. By J. B. N. HENNESSEY, F.R.S., Deputy Superintendent, Great Trigonometrical Survey of India. Received May 4, 1880 (the parts within square brackets August 28). The present actinometrical observations were taken in 1879, in con- tinuation of the series of 1869, published in the “ Proceedings of the Royal Society,” vol. 19 (1870), pp. 225—234.; reference is suggested in these pages for such particulars as are omitted here in order to avoid needless repetition. The series of 1869 and 1879 were taken under identical circumstances as respects stations of observation, actino- meters, and observers ; in both instances the work was carried on only in the entire absence of visible cloud or mist between the sun and the observer, and the sun’s declination during the measurements of 1869 was nearly the same as in the observations of 1879. Hence the two series, separated by an interval of ten years, are thus highly eligible for comparison with one another; it may, however, be added that the work of 1879, now under discussion, is more extensive and systematic than that of the preceding series. 2. The two actinometers used are of the kind invented by the Rev. G. C. Hodgkinson, and described by him in the “ Proceedings of the Royal Society,” vol. 15, p. 321. The instruments are the property of the Royal Society. ‘To distinguish the instruments from each other, I marked one with the letter A and the other with B, in 1869; both are in exactly the same original good condition, including their glass caps, and | may add in particular that the same glasses, and in the same positions, were used in 1879 as in 1869. Hence the constants deter- mined and employed in 1869 were also employed on the present occa- sion; these constants are as follows :— Factor No. 1 for actinometer A, to convert results with Glassvonmmbo results Glass Offi. Vs eric Go aeaee 08 1880.] On Actinometrical Observations, made in India. 155 Factor No, 2 for actinometer B, to convert results with glass on into the results glass off............+.000. 1 C4 Factor No. 3, to express results obtained with actino- meter B glass on in terms of actinometer A glass on.. 0 °982 All the results given in Tables V to VIII, attached, will be found expressed in terms of A for both glass on and glass off, as was done in 1869; it will be seen that only factors Nos. 1 and 3 enter into this conversion. The results of Table IX need no such conversion, as for the purpose in view they are compared for each instrument with 7ts own mean. The numbers hereafter discussed are all in terms of A glass off. 3. The co-ordinates of the stations of observations are as follows :— Height in feet above Lat. N. Long. H. mean sea level. Mussooree...... mee aS ape ees hen Tae ees te 6,937 Welds... sw. SO mim seas GSA Ot asa sane 2,229 The direct distance is thus about nine miles between the stations, which are nearly on the same meridian and are mutually visible. The difference of longitude between the two stations is only 62’°5=42 seconds, Mussooree being east of Dehra. 4, Dehra station is in the Dehra Dun, which is a valley some ten miles wide and about forty miles long, and is bounded on the north by the Himalayas and on the south by the Siwalik range of hills; at its eastern and western extremities there flow respectively the well known rivers Ganges and Jumna. The large native town and the civil and military stations of Dehra lie west and north of the actinometer station within a distance of some two miles, so that the observer at Dehra was unavoidably subject to the disadvantages of the usual smoke and haze envelope which is commonly visible in the winter months over all large towns when seen from a distance, and especially if viewed from a height; on the other hand, the observer at Dehra was not liable to the disadvantages of strong winds. 5. Mussooree is eminently suited for an actinometric station, espe- cially in the autumn. It stands on almost the highest point of an east and west ridge of hills, which falls precipitately 3,000 or 4,000 feet both north and south, so that the observer is absolutely free from smoke and dust, while the atmosphere in autumn is brilliantly clear. But the station from its very prominence is liable to brisk breezes, which some- times blow in strong gusts and always from the south. From these, however, the observer and instrument were protected by means of a kanat (or canvas wall, some six feet high, of a tent), erected at a distance of a few feet, a protection found to be absolutely necessary, for the actinometer is certainly affected by a breeze, especially if blow- ing in gusts. [It will thus be seen that while Mussooree is highly eligible, a similar 156 Mr. J. B. N. Hennessey. [ Dee. we, claim cannot be advanced for Dehra. Further, it may be objected — that the distance between the two stations is not sufficiently great, being only some nine miles. To this can be urged, that in view of the latitude and the sun’s declination, the direct rays to the sun from the two stations, about noon, travelled nearly seven miles apart from one another through the envelope of the earth’s atmosphere: whether this be sufficient or not, is perhaps not so readily apparent. But asa matter of fact, the time at our disposal did not permit of our observing anywhere but at Mussooree and Dehra, so that the choice lay between accepting Dehra or dispensing with a second station. Notwithstanding the drawbacks to Dehra individually, its results appear less lable to distrust if in accord than if in conflict with those at Mussooree: for the latter case visible causes are not wanting, but the former is difficult to account for without assuming special conditions. To this may be added, that distinct mutual visibility between the stations, and the ability at Mussooree to look nearly a mile above Dehra, are not without advantages. | 6. The observations with B at Dehra were taken by Mr. W. H. Cole, M.A., those with A at Mussooree and Dehra by myself.* The procedure prescribed in the “‘ Admiralty Manual of Scientific Enquiry,” pp. 129—130, was exactly followed (as was done in 1869), whereby the change of reading in 60 seconds is obtained alternately in sun (©) and shade (x ) at intervals of 30 seconds (beginning and ending with a © observation;* hence in a series of measurements there result (n+1) of the latter ton of x. Ordinarily the average result from a series is found from aL 1 Sec e ees als sal x nae where R stands for the mean radiation, and the brackets[ _] denote summation. We may, however, exhibit the successive values of radia- tion for 60 seconds by writing R =| a x, )+( Gat Os4 a Se +(Ga* One x») | Lf @Q,+On A h Rh == 1 tly onal Se ence 1 =| 5 55 [Oh This difference is very small, especially if the series be long continued, so that n is large. Accepting the mean value R,, its individual results may be conveniently reckoned as if obtained at the mean of the begin, ning and ending times of successive shade observations; thus the pth result, or * Excepting on Ist and 2nd November, when Mr. H. W. Peychers observed. + See Table IX for example. * Corrections to 32° Fahrenheit being understood. i} 1880. ] On Actinometrical Observations, made in India. Lae R,= Op aes HE Ses, would be tabulated as if corresponding to the mean of the beginning and ending times of x,; no other times need be entered in the table of individual results, which may thus be exhibited in a compact and simple form. 7. Remembering that the actinometer, as at present constructed, is a differential instrument, it appears desirable to regard the causes, to which the measured changes are due, under separate heads, which may be briefly and generally indicated by Instrumental, Local, and Intrinsic or Residual. [These three ‘‘ heads” may be more definitely expressed symboli- cally. If V stands for the measured value of change in solar radiation, suppose V=S8+(L4+/)+ (147) where S stands for that part of V due to true or unmodified solar energy, a quantity which appears unattainable by itself, at least for the present: (L+/) and (1+7) are errors by which S may be vitiated, so as to become V. Of these errors, let (1+7) stand for the portion due to the instrument and its manipulation, such that I can practically be controlled and eliminated, while 1 may imperceptibly exist im combination with S: also let (U+/) denote all the errors appertaining to the locality, 7.e., between the sun and the instrument, during the minute of observation, such that L, arising from visible or otherwise detectable causes, can be excluded, while J, being invisible and beyond endeavours to evade, may also imperceptibly exist in com- bination with S. Then I and L stand respectively for the errors above indicated by ‘“‘ Instrumental” and “Local.” Now, if by skill, care, and vigilance, we succeed in making L=0 and I=0, and obviously acti- nometrical observations are worthless unless there be reasonable pros- pect of securing these conditions, then there remains, as the residual of V, the quantity V,=(84+/+42), but since by definition / and 7 are not visible, nor yet detectable, their presence or absence, in a given result, if generally suspected, can neither be positively affirmed nor denied, appreciably speaking, nor yet estimated. Tor their presence I use, as already said, the designa- tion V, (.e., the residual of V); in their absence, when J=0 and i=0, the designation “‘ intrinsic”? seems suitable, for now V, becomes =S. Hence arose the double designation, adopted above, of “intrinsic or residual,” whereby provision is made for either assumption, without an Vol. XXXt. N 158 Mr. J. B. N. Hennessey. [Dec. 16, attempt to assert which prevails: so that, in the sense here employed, residual and intrinsic (or other equivalent phrase) are convertible terms, as is intended throughout this paper. 'This admission need not, I think, be received as a deterrent to the use of the actinometer under proper conditions, for when we know more of V, the road to S may become easier. Meanwhile, as a matter of fact, the actual radiation by which we are normally affected, at least in sunny lands, is repre- sented, perhaps, more nearly by V, than by S. It may also be stated here, once for all, that the conclusions advanced in this paper, like most others of their kind, are not in- tended to cover more ground than the observations themselves; the former go, of course, no further than the latter. | Of these the residual effect alone presents the real object of measure- ment. Complete elimination of instrumental defects, with retention of excessive sensitiveness, is still a desideratum, and local causes may not only produce overwhelming effects,* but they are so completely beyond estimation or control, that the only remaining alternative is never to observe when they are visible or likely to be present, at any rate if small quantities are the objects of search. As, however, the necessity for placing the actinometer, so far as practicable, beyond local influences, is now so fully recognised, I need only here dwell on one of the further conditions necessary to be seeured. This suggests itself if only on the score of fallibility and the necessity to collect in general abundant evidence. On these grounds alone a series of observations should be prolonged as much as practicable, so as to yield numerous instead of only a few results. Here, however, apart from instrumental inade- quacy, we are met under even the most favourable local conditions, by the varying absorptions of our own atmosphere at different zenith distances, and it thus becomes a matter of primary importance to establish a time-range, during which inconstancy of radiation from this cause may be reckoned as certainly absent, at least so far as the sensitiveness of the instrument can detect.+ In fact, while the obser- vations at varying zenith distances may eventually yield valuable results for reduction to the local zenith, it appears wiser in the first instance to set aside every complicating cause that can be avoided and to establish a daily time-range of the kind indicated. * In course of the present observations I have arrived at the conclusion that the presence of strati, even if distant from the sun, sensibly affect the radiation, while cumuli are comparatively innocuous. + The capability to measure minute changes, besides the power it confers, governs the duration of a single exposure, which in turn is the less likely to afford means of detecting short solar periodicities, the more numerous the latter are within the duration. No doubt a contrivance for yielding a continuous curve would leave nothing further to be desired in respect of periodicities, but Iam not aware that this has as yet been achieved, without sacrifice of the essential sensitiveness, accuracy, and durability. 1880. ] On Actinometrical Observations, made in India. 159 8. Accordingly, during the present series, this time-range was made One of the objects of inquiry; it would most probably be found to occupy an equal hour angle, + and — from the meridian, a point, however, which was itself included in the investigation, by providing that the observations should be made continuous for each day. Eventually, the hour angles adopted were 30™ H., and 30™ W., whereby 21 observations in © and 20 in x would be obtained, yield- ing ten results before, and as many after apparent noon, by the tabula- tion of Article 6; always provided that the observer missed none of the numerous readings, a result which requires some practice to secure in a series exacting continuous attention for so long a period as one hour. In addition to these daily time-range series, the observers were also to take a long range or hourly series (v.e., at every hour, from 8 A.M. to 4 p.M.), on two days, each comprising six observations in © and five in shade, so arranged that the middle result should occur at the hour. The whole of the simultaneous results thus obtained at Dehra and Mussooree are tabulated according to Article 6 in Table V, and may be briefly explained, thus :— 9. Table V.—The times are the means of the times of x observa- tions: they are given by preference in entire minutes, to avoid the needless statement of seconds; but the exact second, or local apparent time, if required, can be readily found by applying to the chronometer time the error in seconds given for each day; thus, on October 31st, the chronometer was fast on apparent time by 5%; this error will always be found to be under +308. The angle between the two local meridians is 45°2, Mussooree being east of Dehra. The results in sun, or © (heat gained), and those in shade, or x: (heat lost), are the observed results reduced to 32° Fahrenheit;* from these, for both A and B, there follows directly the radiation or @+ X glass on, which, in the case of A, was converted, by means of factor No. 1, Article 2, into glass off ; in the case of B, the factors Nos. 3 and 1, were suc- cessively employed to express in terms of A respectively glass on and glass off. Thus the whole procedure in reduction was exactly the same as that followed in 1869. Further, the means of the results before and after noon are given separately together with the estimate of accuracy indicated by their “mean errors;” these latter, it need hardly be stated, cannot recognise errors of a constant nature. The table also includes a record of the barometer, and of the thermometers, wet and dry in shade, and of black bulb in sun, together with an exact statement as to the wind and aspect of sky. In all, the observations at Mussooree include 392 in ©, and 361 in x ; those at Dehra, 244 in © and 217 in x, unavoidably excluding at the latter station several taken on the first four days, because they were beyond * By means of the table of expansion for alcohol by Kopp given in “ Gmelin’s Chemistry.” Nee 160 Mr. J. B. N. Hennessey. [Dec. 16, the time-range adopted. It will be found that the work was practi- cally simultaneous. The radiation results hereafter discussed, are those in terms of A, glass off, the unit being a tenth of a millimetre, or about 0°:002 Fahrenheit. 10. Table VI.—To test the constancy of radiation during the time- range of +4 hour adopted, we might compare the successive indi- vidual Leeullts with one another in each half-hour, just as they stand in Table V ; this comparison, however, would be burdened by errors of single values, which may be reduced with advantage. To secure this end, I subdivide each half hour into three similar sub-time-ranges, and within these limits I take the mean of all the available results for each day to form a group mean; hence, each daily series of group means will be six in number, Braviwed the series was completely observed. The sub-time-ranges adopted, are— het imal hsm: Before noon! 402 6.) Le Se 0intoy elo li 40 ,, 41 48 dig ee ome) ts (0) After moon’ 2. 20. sess ee 207 6 OP Onli ‘O- 12, 50) 220 © 205-5) 0 ero Now, each group mean is the mean of three to five individual results ; the exact numbers of the latter will be found indicated by subscripts. Entering the group means in their proper columns, we obtain in the ease of Mussooree, fourteen complete series (omitting the nineteenth, as it supplies only four of the six groups) ; and, taking the mean for each sub-time-range, we now find mean results from so many as from thirty-eight to sixty-one individual results. These mean sub- time-range values may be considered practically free from all variations, except those due to intrinsic or residual causes (Article 7); no doubt, daily instrumental constants are present, but as the latter will be eliminated in the proposed comparison, inter se, the results in question may be accepted as highly eligible, for the purpose of testing how far the radiation is constant within the +4 hour time-range. 11. As regards Dehra, the group results, from accidental causes already explained, present but three complete series. I pass on to notice the exhibits of Tables VII and VIII before entering on a brief discussion of all the facts. 12. Table VII.—This table also is compiled from Table V, and shows, daily, the sun’s meridional zenith distance, and the mean values of radiation for each half-hour time-range, and for ‘the day, together with readings of barometer and thermometers, and declarations as to the wind and aspect of sky at noon. Finally, individual and mean differences of radiation, M.—D. (.e., Mussooree minus Dehra), as well as the mean radiation at each station are deduced. = 1880. | On Actinometrical Observations, made in India. 161 13. Table VIII.—Table V supplies the materials also for this table, which presents the mean facts of the hourly or long series, taken on the 12th and 14th November, simultaneously, at both the stations of observation. Each series furnishes nine mean results, of which the middle value is at noon. By comparing the radiation at noon with the hourly results for each day, we obtain the defect of radiation from noon corresponding to the change in the sun’s zenith distance. 14. Now, collecting the results from Table VI for Mussooree, we find the mean sub-time-range values to be— — No. of Mean ey) mi: hem. results. group. Biron AD ej ec.. AR Bc Ob" MMAOK EE AB) ee cee BOW -cs7 s&h DOS meer. 0 0) ew. es. Ete OOM cae. Go” mean: Joe Pe Or ce OL oe 908 ple OO sha ens Aad Men O52, WO. 0. DO. aye) meses, | BO, ce sis O49 mean Jor —— from which it appears :— (1.) The radiation is sensibly constant for each half-hour. (2.) The radiation, during the half-hour before noon, exceeds that prevailing during the half-hour after noon; in the present instance, the excess is only six-tenths of a millimetre, but notwithstanding the smallness of this quantity, it appears to be real, not accidental. (3.) Apart from constants, 1t may be inferred from the accordance of the results that the instrument is susceptible of a high degree of accuracy. Again, the above conclusion (2) is very decidedly confirmed by the results for Mussooree, from Table VIII, where the sums of the defects of radiation from the noon value furnish large test-measures of the point in question, and are as follows :— Noy. 12. Nov. 14. Sums for the four hours before noon........ DOG) ss ee i i vi ALE IOOIMN. -\emyerrsy ae BSO! | ace oe After noon— Before noon........ Oy, 2 dene 69 —_—_— ———— Mean (indicating excess of radiation before noon).... NI We 15. The Dehra results in Table VI are not sufficiently numerous or symmetrical to test the conclusions (1) to (3) of Article 14; im fact, they present but three complete series of groups; nor may incomplete series be admitted in this test, because of the undeniable presence of variable daily constants. And with regard to Dehra evidence, in 162 Mr. J. B. N. Hennessey. [Dec. 16, Table VIII, there are obvious inconsistencies in these hourly results, such, however, as have been experienced on some other occasions with similar actinometers. No doubt, in point of eligibility as a station, Mussooree is very far superior to Dehra, as already shown, so that small fluctuations may be expected to disappear at the latter, through the dissipation of energy exacted by its denser envelope; but the sums of the defects present darge measures of comparative radiation before and after noon, and while Mussooree gives a decided preponderance of radiation to the former period, this does not hold at Dehra, as may be thus shown :— | Nov. 12. Nov. 14. Sums for the four hours before noon..... sie BAG. ese pelo ie a - EEbeX MOOI) ys). ye 346 .... 420 After noon— Before noon ......... O: ae 12 Mean (indicating excess of radiation before noon) .... 6 This discrepancy in evidence may, however, be fully accounted for by local haze, which is certainly absent at Mussooree, and as un- deniably is present at Dehra; accepting this conclusion, the ohserva- tions show a fact not without interest, viz., that at the last-named station the local haze absorbs more heat relatively in the forenoon than in the afternoon, a conclusion which can be supported by other exhibits from the same table. And, as regards the inconsistencies in question, whereby the radiation in some instances decreases with decrease of zenith distance, these, also, may to some extent arise from passing local causes, such as are inevitable in the neighbourhood of a large town. But after all these points have been considered, there still remains the fact that separate ‘‘ casts-off” of the instrament are likely to be burdened each with a constant error, by which the whole series may be affected. 16. But though ineligible in the form of group means (as given in Table VI) to test the conclusion (1) of Article 14, the evidence of the Dehra results may be legitimately employed when presented in the form given in Table VII, where the mean results are for + half- hourly time-ranges. Thus we find Before After Before — noon. noon. After. Mussooree mean of first eight days .... 954 .... 947 .... 7 i ¥5 remaining seven days 966 .... 956 .... 10 Dehra mean of complete seven days.... 882 .... 880 .... 2 which are in accord and in keeping with the hypothesis advanced as to dissipation of energy. 1880.] On Actinometrical Observations, made in India. 163 » 17. The facts of Table VII are exhibited in a form suitable for comparison with the similar results of Table II of 1869.* Thus, for the difference of radiation between Mussooree and Dehra, or M—D, we have from the mean of all the results in each case M—D Horuls6Oe trome Mallee ea dy ekki sik a» wl Hore 79Mtromb Waller \ elliot ieee ces 74, Dintheremces Rael. seo s 3 where it will be remembered that M—D is independent of all varia- tions which affected the two stations equally at each epoch. The result shows no change of relative radiation in 1879 as compared with 1869. 18. I next compare the radiation results at each station for the two epochs, and these, no doubt, are subject to all the indicated causes of change, some of which can be recognised, and even roughly estimated. In the first instance, however, I accept the results as exhibited, and compare them thus :— * Means of all the Ltesults. Mussooree. Dehra. Mrs OOo Malle: WW 2k ed ece Be lS) mei ced: 902 Mera/9 Mable, VAAL bcs. gcaces G5 AV ete tee 877 DWitierence om I) eerie PAG 25 where the very close accordance of the two results suggests that they represent intrinsic or residual causes solely. The magnitude of D, is, however, liable to correction, from two causes,} because its components are not in the same terms; both the causes, however, affect the two stations equally. Cause (a.) In 1869 the time-range was ........ as ll ln@mr, In 1879 i MM ch i te Roel ore Se ey LOOT. Dittenence as alae 5 hour Eee roew toy. S0c., vol. 19) p. 229. f A third cause (c) may also be noticed, viz., that presented by a change in the earth’s radius vector ; reckoning the effect of this inversely as the squares of the radius, there results a percentage of only 0'4 of the unit of radiation adopted in this paper, ¢.e., one-tenth of a millimetre: this result is quite rejectaneous. It would tend, however, to increase the magnitude of Dj. 164 Mr. J. B. N. Hennessey. [ Dec. 16, Cause (b.) In 1869, mean of sun’s meridional zenith distances (at Mussooree)........-... 44°°6 In 1879, mean of sun’s meridional zenith distances (at Mussooree) ............ 47°°3 Difference) 22 7s ote eee hence, to make the results of 1869 strictly comparable with those of 1879, the former (or D,) must be increased for (a) and decreased for (b). We might estimate these corrections empirically, proceeding on the basis afforded in Table VIII of the defect of radiation correspond- ing to + 1 hour to + 21 of sun’s zenith distance. It appears, however, sufficient to note that the effects of (a) and (0) are of con- trary signs, and that the excess of (b) may be set down roughly at about five units, whence D, would be reduced to about twenty, of which the principal portion, if not the whole, may be ascribed to intrinsic or residual variation. Hence, it may be asserted with confidence, on the evidence adduced, that the solar or residual radia- tion in 1879 was less than in 1869 by so much as 2 per cent. If we imagine this result to hold good for the twelve months, some notion may be received of its consequences by conceiving that, in point of heat-rays at least, the sun was:abolished one entire week in 1879. [To this may be added, that since the larger radiation of 1869 cor- responds more nearly than the smaller radiation of 1879 to a period of maximum sun-spots, this result confirms, so far as the evidence goes, the hypothesis of greater solar energy at maximum than at minimum epochs. | 19. It will be seen in the column of mean results for the day, Table VII, that considerable differences appear. on a comparison inter se; at the same time that the several individual results for the day (an Table V), of which the means are composed, exhibit comparative harmony. ‘This leads-to the conclusion that all the results for each day contain one or more constants; but it is by no means a simple matter to show by experiment* how these constants may be sub- divided between intrinsic or residual and instrumental causes; as to local causes, they may be disregarded at least at Mussooree. That instrumental causes do exist I am strongly inclined to believe, though probably they eliminate one another in the mean from a large number of days; but supposing them to be real, these causes are in all likelihood connected with the preliminary adjustment of the fluid, by which a sufficient quantity of the latter is ‘‘ cast off” into the surplus bulb above, so as to make the head of the column play up and down * Some experiments have been made, but they are not sufficiently numerous to justify a conclusion. 1880. | On Actinometrical Observations, made am India. 165 within the range of the scale. In an instrument so essentially differ- ential as the actionometer, any adjustment involving a change of circumstances cannot be too earnestly deprecated. On the other hand, without excessive sensitiveness, the instrument can command only a very limited range of utility. 20. There remain to notice a few experiments made in view of very short period fluctuations in the solar or residual radiation ;* these are given in Table 1X. On this occasion the two instruments were set up at Dehra within three or four feet of one another; both were read by means of the same chronometer placed between them, and the two observers capped and uncapped their tubes at the same times. Thus, the readings were taken at the same instant, and under pre- cisely identical circumstances, the observations being continuous from 11h. 39m. to 0h. 31m. apparent time. Taking for each instrument the difference between each result and the mean of all, we obtain the values in columns dA and dB. Now, the magnitudes of these changes are undoubtedly in excess of fallibility in reading, for the eye can cer- tainly read to one-fourth of a scale division (or less), ¢.e., to + millim., or about 0°:005 F., so that apart from calibration errors, which are not likely to be excessive, and which in the two instruments are almost certain to be dissimilar, the inference is that these large differ- ences are at least in part due to solar or residual causes. ‘This con- clusion is numerically tested in the last columns of the table, where I have placed every pair of dA or dB, in which either member exceeds ten in magnitude irrespective of size; twelve such pairs occur, and it may be worthy of notice that the two members of every pair without exception are affected by the same sign; so that so far as the evidence goes, both instruments recorded a rise, or both recorded a fall. To present a large argument of the fact, I take the sums, disregarding signs, of each column, from which it appears that A recorded 151 units of change, and that B recorded no less than 138 units, and in the same directions. ‘The result, so far as it goes, confirms the conjecture that the solar or residual radiation is remittent, and in very short periods of unknown duration. [1 cannot too earnestly express my hopes, that actinometrical observa- tions will soon be begun on at least two of the several elevated and eminently eligible sites which India offers. A series conducted sys- tematically and skilfully for even one twelvemonth could not fail to throw much light on a subject which, in its eventualities, concerns every individual on this globe far more than is perhaps commonly contemplated. As to the more immediate questions of periodicity, &c., these cannot be more than approached by means of desultory observa- tions, such as those here presented, undertaken under the pressure of * See “Proc. Roy. Soc.,” vol. 19, p. 228, Article 12. 166 : Mr. J. B. N. Hennessey. [Dec. 16, daily official duties, and with little prospect, though with hearty desire, to command time for more continuous and conclusive results. | 21. For support and encouragement in making these observations, my acknowledgements are due to Major-General J. T. Walker, C.B., R.H., F.R.S., Surveyor-General of India, whose appreciation of scientific inquiry is well known. 22, In concluding my remarks on the Mussooree- Dehra observations, I gladly avail myself of the opportunity to heartily thank my friend Mr. W. H. Cole, M.A., whose skill as a trained observer, and whose co-operation in general have enabled him to render valuable aid. Observations by Captain J. P. Basevi, R.H. 23. It only remains to offer a few words on the results, exhibited in Table X, of actinometrical observations made by my friend the late Captain J. P. Basevi, R.H., of the Great Trigonometrical Survey of India. 24. When this officer, in course of the pendulum observations, was about to resume his travels in 1871, it occurred to us that he might utilise some rare opportunities for actinometrical observations which would present themselves at points of considerable height above sea level that he would certainly need to pass over. With his usual love for scientific research, Basevi readily consented to use the actino- meter on suitable occasions, and he was accordingly provided by me with the instrument A of the Royal Society. The intention to observe at great heights was unhappily frustrated by his lamented death, or there is no doubt he would have secured valuable results at very con- siderable altitudes, including the Takalung La, or pass, on which he stood at 18,060 feet above sea level. He, however, took some pre- liminary observations at small heights, chiefly at Srinagar, the capital of Kashmir. Not being sufficiently numerous fora separate communi- cation, they have remained in my hands since 1871, when they were taken, awaiting an opportunity, such as now presents itself, for placing them on record. This is done in Table X. 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SL “UBOTAL ‘PL “AON ‘OL “AON PL “AON “FAL “AON ‘q8Iq he eS yyue7 ‘MOO NT Pons ULOTF JOOFOC, WOTZVIPTyT UOTJLIPBY IBlOG ‘I = 90100ssnql V Pp 2 ooo°o°o OnANM ‘HO ssvps “Vv Jo suut0, ut possoidxo pure ‘gq dojoUIOUNOY YIM vay ye pus ‘YW aojomOUTOYW YIM sat0ossnyy 42 ATSnosuRyNUIIS VIPUT UI poarosqo ‘simoy eArssooons qv sdnoas OF s}[UseY UOTZeIpey UvopY ‘Sollog SIOT—'TITA qe, 192 Mir eye Ne Hennessey. [Dec. 16, Table [X.—Simultaneous experimental Observations at Dehra, the two Actinometers A and B being set side by side, and read by means of the same Chronometer. 1880. February 27. Apparent Time. Beginning. End. | h. m. 8 h. m. s. 1139 0/1140 0 40 30 41 30 42, 0 43 O 43 30 44 30 45 0 46 0 46 30 47 30 48 0 49 0 49 30 50 30 51 O 52 0 52 30 53 30 54 0 55 (O 55 30 56 30 57 O 58 0 58 30 59 30 2. 0 10 | 12° 1 © 1 30 2 30 3 0 4 0 4 30 5 80 6 0 7 0 7 30 8 30 9 0 10 0 10 30 11 30 12 0 13 0 13 30 14 30 15 0 16 0 16 30 17 30 18 0 19 0 19 30 20 30 21 0 22 0 22, 30 23 30 | 24 0 25 0 25 30 26 30 27 0 28 0 28 30 29 30 30 0 31 10 Observed results reduced to 32° F. Radiation by | | dA. 812 | 835 | 809 | 830 806 | 838 796 | 824 816 | 843 809 | 824: 800 | 825 815 | 840 dB. Values ex- }. ceeding 10. dA — dB. dA. | dB. +11 $417 46 + 2/+13 + 30 —19 |—16 | 1880.] On Actinometrical Observations, made in India. 193 Table X.—Observations with Actinometer A, by Captain J. P. Basevi, R.H. °.2 | ~¢ | Thermometer. ee wis eMa lS © ° S565 8 A aai|ls Boe | Sa | 1871. Me 2 Sena ee 2 fe H In shade. Ta =| co cs| gas = a) elzeldeelda! 3 si Sayre lbaes 7 | 8.5 black = | Be | ea sce te |) Dry niet) canner At Sialkot. Lat. 32°31’. Long. 74° 36’. Height, 835 feet. h. m. a April 26..}11 41] 19:1 913, 29°48 85'8 75°3 151°4 At Jalapur. Lat. 32°33’. Long. 74°16’. Height, 850 feet. April 28../12 7{| 18:5 | 898, | 29°35 | 92:9 | 786 | 1622 At Srinagar. Lat. 34° 5’. Long. 74° 51’. Height, 5,209 feet. Maylb...j/11 O; .. 867; 40 24°93 72:2 65°0 | 139°0 12 O} 15°3 9073 ae 93 745 66°4 | 143°5 Ae Oso < 9045 3 ‘91 | 77:0 | 679 | .. 2 0 925, |—18 ‘91 | 789 | 685 3 0 895, 12 88 80°0 69°7 4 0 360, | 47 87 | 800 | 697 Mayl16...| 8 O 772, | 137 24°93 63°5 59°6 | lil 9 0 822, | 87 ai “ elas 10 O 871; 38 “95 71:2 64:0 | 1348 BE Ol 3. 9053 4 96 748 66.8 | 142°8 12 O} 151 9093 ate 92 77-0 681 | 145°0 ON i 927, |—18 “92 79'8 68°7 147°5 May 19...) 8 O 782, 137 24°81 63°8 602 | 110 9 0 859, 16 “83 66°2 614 | 125 10 0 9007 19 85 68°4: 62°5 | 133°8 EES Os. 904, 15 82 72:0 62°5 | 139 12 O| 144 919, a 83 74:0 644 | 141°7 Oy. 897, | 22 ‘81 | 756 | 645 | 143-2 7a (0) &86, 33 “80 774 65:0 143°7 3. O 875, 44 80 78°5 63°6 | 137:0 4 0 823, 96 ‘76 79:0 64:8 | 1383 194 Dr. W. Ramsay. [| Dece. 16, II. “On the Critical Point.” By W. Ramsay, Ph.D., Professor of Chemistry in University College, Bristol. Communicated by E. J. Minus, D.Sc., F.R.S., Young Professor of Technical Chemistry in Anderson’s College, Glasgow. Received November 8, 1880. The experiments to be described were undertaken with a view to determine the difference in behaviour of two pure compounds, and a mixture of the two, at high temperatures, and under great pressures. The two liquids selected were benzene, C,H,, and ether, C,H,,O ; for both are remarkably stable bodies, and both can be obtained easily, and in a perfectly pure condition. They are also without action on each other. The benzene was produced by the distillation of calcium benzoate with lime; it was dried by cohobation with sodium for four days, and then distilled. It boiled at 81°4 at a pressure of 750 millims. The ether was also cohobated with sodium for four days, and boiled at 34° °4, The pressure-apparatus resembled that used by Dr. Andrews in his experiments on the critical state of carbonic acid, somewhat modified to suit the altered conditions. The gauge for measuring pressure was a carefully calibrated thermometer tube with round bore. No correc- tion of capacity was necessary to allow for a conical space at the end, as is usual with air manometers, for the sealing of the tube was. accomplished by drawing up a plug of fusible metal, and allowing it to solidify. As the gauge lay horizontally, no correction was necessary for varying height of mercury. It was carefully filled with dry air, after its capacity had been ascertained by filling it with mercury, and sub- sequently weighing the mercury. The probable error of the volume of one division is 0°23 per cent., and the probable error of the total capacity 0°084 per cent. The measurements of pressure may therefore be regarded as a close approximation to absolute correctness, and as. perfectly correct relatively to each other. The temperature was corrected for the mercury outside of the heat- ing apparatus, and after the experiments were over, was compared with a good unused new thermometer. The readings did not differ by more than 0°5 degree. | The liquid to be examined was contained in a piece of very narrow barometer-tubing, graduated in millimetres, and was introduced ata — temperature close to its boiling point, after a portion had been boiled off, so as to ensure absence of air. While entering the experimental tube the liquid never came in contact with air, and from the results. of experiments it appears that none was present. Observations of the condition of the lquid experimented on, and. 7 1880.] . On the Critical Point. 195 readings of its volume, were taken by means of a telescope placed about one foot from the tube. The readings to tenths of divisions are computed by eye, and are only approximately correct. The tube containing liquid was heated in a copper block, in which a slit was cut open at the upper surface of the block, to permit observations being taken. The block was covered with a plate of glass and heated. It was found possible to keep the temperature constant to within ,th of a degree for several hours by this arrangement. Benzene was selected for the first set of experiments. While tem- perature was kept constant, volume was altered, and the corresponding pressure noted. The volumes are given in divisions of the tube, for the bore was almost perfectly uniform, and the unavoidable error in reading more than compensated any correction which might have been made. The numbers refer to the curves on the accompanying woodcuts ; the curves are isothermal. The pressure corresponding to each change of volume forms the ordinate of the curve, and the volume itself the abscissa. aT 6] mm 2) 10) iS a ™ BENZENE [Dec. 16, Dr. W. Ramsay. 196 2.7e= A || "G.Z8= A § ‘e.ce=A T 02-04 : 40-14 6-29 23-98 || a G2-e2, 14-498 69-9 64-6 tL-88 as PP-L9 ZS-F9 ZL.19 16-¥¢+ OT-64 LE-3L 66-99 86-19 19.68 99.79 92.06 LT-9L 04-02 BE-FY 19 6ST $8.8 91.79 PP-L8 96-12 G8.89 ss Wy LT-4S 3 10-98 a0 $2.19 a 18-8¢ ox ro PS.0L 08-99 Gg.09 a Go-1¢ a 66-88 C8.69 ee °° eo ee ee 06-08 18-19 $S.S9 G¢.09 18-8¢ 76.96 L6-F5 19-44 26-99 Zo-F9 GS.09 a bs oy 48-SL 08-99 Zo-F9 89-09 18-8¢ GO.L¢ 88.9¢ 08-89 08-09 es aie ¥ 69-24 6-59 80-€9 08-09 €6:8¢ C0.L¢ 88.9¢ 98-69 80-9 80.89 08-6¢ GP.g¢ LT-LS 88.9 ¢8.89 GO-19 08-09 60-88 €9-1¢ 28-9 L2-9¢ 08-79 PS-6S 1Z-8¢ 09-9 6F-9¢ €8.¢¢ 62-G¢ WetAte ‘P-oL0€ ‘0-962 ‘L-o16B "P-.886 'S..98G "L-oP8S YE ‘XI S00. ‘TIA TA "A “AI ‘soroydsouryy Ur otnssorg ‘SE8=A 4 C-08=A x ST-66 06.66 98-0F G0-8¢ 86-8& = LL-LE VS-8 66-18 €9.8¢ PPLE LE-66 €L-LE VE-66 09.86 VE-66 ¢9-8€ OF-62 6L-8& LE-66 61-8& 6S:.66 88-26 99-66 88-L¢ LE-66 69696 Loh 8G aa ‘Il aI ‘OUINTO A. ‘quOZUOG LOZ STIEYZOST—'V [QB], 1880. ] On the Critical Point. 197 Table B.—Isotherms for Ether. | Pressure in Atmospheres. cet i | | Bee ge Ve Vib. 2 eee p= 154e-7, |, 179"8. | 198%5. | 19575. | 201°). | 207°1. | 2aK°! S0-.....| 1952 | 29:07 | 35:53 | 37-44 | 39-72 | 41-45 | 45-75 80......, 1960 | 29°47 | 3653 | 3855 | 41-45 | 42:94 | 48:07 70......| 1967 | 29°71 | 3676 | 3886 | 4212 | 4440 | 50:33 eee... igeae Pg gi s, Sy Ds Ne haa ieee 619:83 | 3012 | ‘37-39 | 39:50 | 43:07) 45:97 | 55°61 BO.....-| 1969 | 3012 | 38°08 | 40:17 | 44:33 | 47-81 | 59-05 1S oe ipa e i 45°39 | 48:30 | 64°80 M22) ..| 19°88 30°12 | 38:39 | 41-45 | 4830 | 51:51 | 73-25 See. | | Senks - 43°59 | 50°78 | 53°33 | 78°88 2p | 1. | 41:45 | 44°68 ig | Baer: : | 46:19 | 55°50 | 59°54 35......| 1969 | 3012 | 45:03 | 4797 | 5893 | 63:22 30°31 | | 48°87 | 63-22 22 Sao an 31°61 54°76 51°79 68°84 74°78 | 22 ord So | 36°00 61°46 54°76 Be ile < Se 43°55 73°06 72°50 Rees as 19°72 93°43 | 86°52 | 198 Dr. W. Ramaay. [Dec. 16, 30 MIXTURE OF BENZENE AND ETHER, ~ Table C.—Isotherms for a Mixture ot Equal Weights of Benzene and Ether. | Pressure in Atmospheres. : Volumes. |— nee es es ge eenle IV. Vv. | | T=215°6.| 225°2. | 235°-6. 240°-7. 252°-9. | | | SOV eer te 33°15 | S778 | 43,07 43°99 47°81 Ses eC | 3405 | 8886 | 44°32 45°75 49:04 | Bien Wye, 8. |e! BATA 38:86 | 45:25 46:49 51:70 GOe es ee she B84:55 1 N39 40r elgg 47°33 53°23 | SO ence. seh cus. |. Ok 9S che 40: O25. TAG a2 ee ade 54°99 | Arman uN nalse voi U8 eo ws | ae | 48°46 56-16 | AO. . 35:06 | 40°86 | 4650 | 49:29 58°51 | SON SAARC Means os sige | mie | a6 nie 60°55 | Ee a ine SU abe 5 4114 | 49:38 53°38 63°22 Sie aeeoiann ys. b e | a | 51:05 53°83 71°59 Bone hoa cd Wane: 41:45 | 53°73 | 56:60 7617 Boe enh Wi ie | Es | 5638 "| sO | OU a ee ae ie AS 35 qe Glas 65°84. SOS beget del B4tS4 210 4766 ee Gmeo DOW a eMac, 3455 | 53:93 | | SYS ee am OMN eMay”1547 0 2 66-48 | 1880. | On the Critical Point. 199 It may be remembered that Dr. Andrews, in his “Research on Carbonic Anhydride,” never obtained the gas absolutely free from air, consequently, in diminishing the volume of his gas, in contact with its liquid, he always noticed that a slight increase of pressure was neces- sary. If the curves representing the behaviour of benzene under similar circumstances be referred to, it will be noticed that the pressure actually is reduced, in producing diminution of volume, in Curves I, II, III, and IV. A relic of the same form of curve remains. in the behaviour of a mixture of ether and benzene, but no trace is observable in the behaviour of ether. The explanation appears to be that the molecules, when the gas has been compressed to a certain extent (very shortly before all gas is condensed to liquid), begin to exert some attraction for each other. and consequently relieve the pressure. The explanation of the fact that this phenomenon is notice-- able in the case of benzene, but not with ether, is perhaps connected with their different behaviour at higher temperatures : the meniscus of benzene is always easily distinguished, even up to its vanishing point ; whereas that of ether soon becomes extremely mist-lke and hazy. I have little doubt that many other substances, when heated under pressure in a condition absolutely free from the admixture of any other gas, will show similar results. Probably, closely connected with this observation, is another :— namely, that it is possible, after condensing all gas to liquid by pres- sure, to lower the pressure very considerably without ebullition of the liquid, and consequently without formation of gas. At a temperature of 228° for instance, it is possible gradually to reduce the pressure from 29 to 22°4 atmospheres without any evolution of gas in the case of benzene; sudden ebullition then takes place, and the pressure rises to 29°3 atmospheres, the volume at the same time suddenly increasing to 65. This behaviour is represented by a dotted line in the diagram representing the isotherm for benzene. The dotted line in the second isotherm represents a similar phenomenon; the pressure could be reduced to 35°4 atmospheres before sudden ebullition took place. At higher temperatures, a very slight reduction of pressure caused ebullition, but the phenomenon could still be noticed, although no attempt to measure it was made. The same phenomena were noticed with ether, and are also exhibited on the diagram. It is necessary, before discussing the results of these observations, to give some tables, showing the relative proportions of gas to liquid at the various temperatures chosen; always, of course such that it was possible to distinguish the two states of matter easily from each other. I have thought it sufficient to reproduce merely those of benzene and of its mixture with ether ; for the behaviour of ether does not materially differ from that of the mixture. The curves con- structed to exhibit these relations graphically have for their ordinates. 200 Dr. W. Ramsay. [Dec. 16, the volumes of liquid capable of existing at particular temperatures, the latter being represented as abscisse. The curves may be termed curves of eguivolume, for the total volume of gas and liquid was maintained constant through each. 4 m x a] ™m A > 24 zi) m VOLUME -OF LIQUID BENZENE Benzene. Curve of Equivolume, expressing Proportion of Liquid at each Temperature. ‘Temp..... 234°°7 252°°9 274°°4 284°°1 286°°2 288°'4 ‘Volume. OOM OAS ee) Lae O at oO" af LW) Se 0) 0 SO OED wiial o VART yn Os Ol meses Ore ts 0 0) TAY) ae ae We Gh. ne. porlaOeere Orlane! 1:5 D) Ow 1D Ae \I9D0, nix AVS oe AA eee 4, MO 9 2075 es = >) 20°79 a B16 ay 228 oe Oe ee WO et QA G ocr. QB cae 2) QbRiarees. 30:00% 4: SUS en Sneed he Only eis 2 2oi AU) ol2:... 982°) soe ees 1880. } On the Critical Point. 201 CLOUD See 49 20 10 VOLUME OF LIQUID MIXTURE OF BENZENE AND ETHER Temperature........ 215°6 225°°2 235°°6 240°°7 Volume. Sh) pea ete koala Te Oreos Si seo ISLS aA Rete thee 0 de heatiepeaa aie ORO tte Oe eM erie Reece 0 HOO A een, dey: CoS sues all be oo wa aaa eg see ae 0:2 O10) ) pia Mg cated Mor wee Ong ea he Oe cane oe 3°4 SL sealed EOS eee OO = eer ZO ves. Cloma A (0) i igdineene rage PLS) nese ags eA AS AS hatin ade) NAS Joan aaa “i D0) kane DADO yt Or Or hee eee | faces oOo) The critical point.—The critical temperature of benzene lies about 291°-7. At that temperature, no decided meniscus could be pro- duced by slowly altering the volume of the substance, but the tube remained full of flickering striz. On increasing volume from 50 to 70, the flickering striz disappeared, and the matter contained in the tube appeared to be wholly converted into gas. On the other hand, by diminishing the volume to 35 divisions, the flickering appearance again vanished, for the whole of the contents of the tube were con- densed to liquid. At higher temperature, no line of demarcation be- tween liquid and gas was observable. This observation, and similar ones made with ether and with a mixture of benzene, contradict the statement made by me in a note published in the ‘Proc. Roy. Soc.,” vol. 30, p. 323, I stated there that the temperature at which the meniscus disappears depends on the relative volumes of the liquid and gas. I have now to acknowledge that the observations on which this statement were 202 Drew: Ramsay. | [ Dec. 16, based, lead to an opposite conclusion when correctly explained. The heat in these experiments was imparted to the tubes through a large block of copper, in grooves in which the tubes were placed. I have no doubt that the temperature of the copper block represented accurately that of the tubes; but not that of the lquid contained in the tube. When the temperature of the tube is raised, however slowly, evapora- tion of the liquid in the tube ensues, and time is required for evapora- tion. During this time, the temperature of the copper block is rising ; and with a tube insufficiently filled, 1t appears necessary to allow a longer time for evaporation, than with one containing more liquid. On reading temperature when the meniscus vanishes in the former case, it will appear higher than in the latter. The difference is ac- counted for by the fact that during evaporation, the temperature of the copper block is continually increasing. This would point to the con- clusion that a considerable amount of heat must be absorbed, even under such circumstances, in order to convert liquid into gas, and thus that the latent heat of vaporisation is still considerable, even at temperatures so near the critical point. The critical change for benzene occurs at a temperature of 291°7, and at a pressure of 60°3 to 60°5 atmospheres, and the isotherm at this point is represented in Curve VII of Table A. Between the volumes of 90 and 60 it is evident that gas is being compressed, for pressure rises regularly. But from 60 to 38 the rise of pressure required to produce diminution of volume is smaller proportionately to the effect produced, and after the volume 38 has been reached the pressure rises much more rapidly. And, on referring to Table D and to the accom- panying diagram, it is also to be remarked that, when the volume is 60, or greater, the curve of equivolume represents the total evapora- tion of the substance. With a volume of 50, that particular propor- tion of gas to liquid appears to be reached at which evaporation almost exactly balances expansion, and neither total evaporation nor total expansion takes place, but the ratio of gas to liquid appears to remain unaltered. With volumes of 40 and 35 divisions of the tube total expansion takes place, and the tube, above a certain temperature, must become filled with liquid. Above the temperatures represented in Table D, it becomes impossible to distinguish liquid from gas, for the meniscus has disappeared. But I can see no reason for assuming a particular state of matter under such circumstances. In the prelimi- nary note already referred to, I described an experiment, in which liquid and gas were kept separate for some time by means of a capillary tube, and in which even after the meniscus of the liquid had disappeared, a solid, adhering to the wail of the tubes containing presumably only gas, refused to dissolve. This experiment has been frequently repeated, with identical results; it is, perhaps, most striking when the fluorescent colouring matter, eosine, is used as the solid. Hosine fluoresces only 1880. ] On the Critical Point. 203 when in solution; when dry, it is a red powder; and when alcohol containing eosine in solution is placed in one compartment of such a tube, the other having its sides coated with a thin film of dry eosine, no fluorescence takes place till time has been given for diffusion. In fact, the rate of diffusion may be approximately measured by the increase in intensity of fluorescence in that half of the tube originally containing the vapour of the solvent. Three facts appear, therefore, to be demonstrated :—First, that at the temperature at which the meniscus of a liquid disappears, and at _ temperatures above that point, but not far removed from it, an in- crease of pressure is required to cause diminution of volume, com- parable with that necessary to compress a liquid at a temperature somewhat below that at which its meniscus disappears; second, that when a mixture of liquid and gas is maintained at a certain volume, the expansion of the liquid on raising the temperature, so long as it is possible to distinguish liquid from gas, points to the ultimate occupying of the whole space by liquid at temperatures above which the meniscus becomes invisible; and third, that under such circum- stances the liquid retains its solvent powers, while the gas is incapable of dissolving a solid. All these facts point to the conclusion, that at or under such a volume the matter is really in the liquid state, whereas at a greater volume, the matter must be viewed as consisting at least partially of gas. No direct experiments have been made with a view to ascertaining whether heatis evolved when a gas is converted into liquid by pressure at such high temperatures. I hope to be able to execute some experi- ments which promise some satisfactory answer to the question. It now remains to consider the condition of raising a mixture of two liquids to such a temperature that the meniscus disappears. Isotherms for a mixture of benzene and ether are given on Table C, and graphi- cally represented on the diagram. The first isotherm at the temperature 215°°6 is at least 20 degrees above the temperature at which the meniscus of pure ether disappears, and yet the tension of ether vapour does not markedly appear. If that curve be constrasted with Curve No. VI for ether alone at 207°'1, some 8 degrees lower, it is noticeable that diminution of volume in the latter case is accompanied by a much greater rise of pressure than in the former. The presence of benzene, therefore must exert some marked influence on the pressure exercised by ether vapour, and cause the mixture to behave to some extent as a single substance. But at higher temperatures the influence of the ether becomes more marked, and at the temperature 240°°7 the critical point is nearly reached. The tube then appeared full of mist, till the volume 40 was reached, when the mist disappeared, and the tube appeared full of liquid. The pressure at which ether becomes critical is situated about 204 . Dr. W. Ramsay. [ Dec. 16, 40 atmospheres ; that at which benzene reaches the critical state 60°5, and that of the mixture 48. The temperatures are: ether, 195°5; mixture, 240°°7; benzene, 291°:7. Both temperature and pressure thus appear to take a position not far removed from the mean of the two. The definition of the words liquid and gas appears to require more accuracy than has hitherto been bestowed. Asno known eriform body absolutely obeys the law of contraction inversely as the pressure, and equal expansion on equal rise of temperature, there is apparently no instance of a perfect gas, although this state is closely approached by such gases as hydrogen, oxygen, and carbonic oxide, especially at high temperatures and not too great pressures. And the definition of a liquid appears to be a fluid exhibiting surface tension. Now, above the critical point, this surface tension disappears as has been repeatedly shown. But I venture to think that the possession of surface tension is not a criterion of the existence of a liquid. And a most striking argument in support of this theory has lately been furnished by M. Cailletet (“‘ Compt. Rend.,” xc, 210). He found that carbonic anhydride at a temperature of 5°°5, when the lower portion of his experimental tube was filled with liquid, the upper portion being filled with a mixture of gaseous carbonic anhydride with air, mixed with the air when a pressure of 130 atmospheres was applied. The question is a simple one; does the gas become liquid, or the liquid become gas P Or do they both enter a state to be called neither liquid nor gas? I venture to bring forward a theory, with great diffidence, which appears to be supported by numerous observations, viz., that there exists a close analogy between the condition of liquid as compared with its gas, and of a compound as compared with the elements of which it is constituted, and that in the evaporation of a liquid we have to do with a true instance of dissociation, that is, a decomposi- tion of complex molecules into simpler ones. Many compounds, when heated, dissociate into their elements, or into simpler compounds. The extent of dissociation is a direct function of the temperature, and an inverse function of the pressure. Thus, ammonium chloride, when heated, dissociates into ammonia and hydrogen chloride; hydrogen iodide into iodine and hydrogen. It is evidently possible so to regulate temperature and pressure as to obtain a mixture of hydrogen iodide with hydrogen and iodine in any desired proportion. If the analogy holds, it is possible to obtain a mixture of liquid molecules with gas molecules in any desired proportion ; but as surface tension appears to be permanent until liquid and gas reach the same density, mixture does not occur before that point. Still, mixture may be held to exist to some extent, for the vapour is not a perfect gas, and this is pro- bably owing to its containing some liquid molecules among its gaseous ones. 1880. ] On the Critical Point. 205 The question is also closely connected with that of heat of vaporisa- tion and heat of combination. It is possible to exhibit this point more clearly by help of an example. The heat of vaporisation of water, under a pressure of 760 millims. is 513 calories for 1 cub. centim. at 100°. The expansion which the liquid undergoes in becoming gas is represented by the number 1623. From the known equivalent of heat in work, it is easy to calculate the total work necessary to evaporate water; and also the work required to expand the substance 1623 times against atmospheric pressure. The work done as heat, in the case of water is 221'1 kilogram-metres; and as expansion, 16°6 kilogram-metres: hence 221:1 — 16°6 is work done in overcoming molecular resistance. But this work is infinitely more than is necessary to overcome surface tension, and the most probable conjecture is, I venture to think, that the work is employed in dis- sociating the complex molecules of water into simpler molecules of water-gas. Now, mm the foregoing paper, experiments have been described which show that when a liquid is heated in a certain confined space, the results of observation, possible while the liquid is still distinguish- able from its gas, lead to the conclusion that at a temperature at which the meniscus of the liquid has disappeared, total expansion of the liquid will take place, and that a certain larger volume, total evaporation will ensue. It may be objected that Regnault’s measurements of the heat of vaporisation of liquids at high pressures appear to show that it is a quantity diminishing with the temperature. But it has never been shown to be the contrary in the case of heat evolved during chemical combination. Is it not likely that there will be a less evolution of heat during the combination of hydrogen and iodine at a high than at a low temperature and pressure? And to return to M. Cailletet’s experiment, is it likely that compression, which, as a rule, has the result of turning gas to liquid, should in this case change liquid to gas? To sum up: the views expressed in this paper are:—(1) That a gas may be defined as a body whose molecules are composed of a small number of atoms; (2) a liquid may be regarded as formed of ageregates of gaseous molecules, forming a more complex molecule ; and (3) that above the critical point, the matter may consist wholly of gas, if a sufficient volume be allowed; wholly of liquid if that volume be diminished sufficiently ; or of a mixture of both at inter- mediate volumes. That mixture is, physically speaking, homogeneous, in the same sense as afmixture of oxygen and hydrogen gases may be termed homogeneous; but chemically heterogeneous, inasmuch as it consists of molecules of two different natures. When prevented from mixing by interposing a capillary tube between the two, the liquid and gas retain their several properties. MOL. XXXI- Q 206 Dr. C. A. MacMunn. Researches into the [Dec. 16, III. “ Further Researches into the Colouring-matters of Human Urine, with an Account of their Artificial Production from Bilirubin, and from Heematin.” By CHarues A. MacMunn, B.A., M.D. Communicated by Dr. MIcHAEL Fostsr, Pree- lector of Physiology in Trinity College, Cambridge. Re- ceived November 10, 1880. In a former paper which I had the honour of laying before the Royal Society, I endeavoured to describe the spectroscopic and some of the chemical characters of febrile urobilin. In the present paper I have given the results of further spectro- scopical research, which had for its object:—(1.) To determine the differences which might exist between those urinary pigments which are recognisable by means of the spectroscope, in health and disease. (2.) The isolation of normal urinary pigment, giving the band at F. (3.) To attempt to trace back to their source all these pigments. (4.) To examine bile more carefully for the presence of urobilin. (5.) To find an explanation of the absorption-bands noticed in the bile of certain animals. In this paper I shall give principally the spectroscopic appearances of these pigments, reserving for a future communication a full de- scription of their chemical characters. Speculation will be avoided as much as possible, and a plain statement of the facts which presented themselves will be adhered to, which show that there is irresistible evidence of the relationship between the colouring-matters of blood, bile, and urine. It is probable that a knowledge of how the urinary pigments can be prepared artificially will be of great use in enabling us to under- stand how they are produced in the body. Thus the knowledge of the fact that the spectrum of urobilin varies according to the amount and the kind of oxidation, or reduction, or both, to which it has been subjected in the body, which I shall endeavour to show is the case, is of great importance, especially as we can produce in the laboratory pigments (from bile- and blood-colouring matter), by a greater or a less amount of oxidation or reduction, or of both combined, which can be made to resemble exactly pigments obtained from urine in health and disease. The Spectrum of Normal Urine: Its Band due to the presence of a Pigment indistinguishable from Choletelin.—In examining urine obtained from individuals in a healthy condition, I always can see a band at F, and when a layer sufficiently deep to show this band is treated with caustic soda, caustic potash, or ammonia, the band can be no longer seen. On the subsequent addition of an acid, it is again brought into view. But if the urine be obtained from a febrile case, or indeed, 1880. | Colouring-matters of Human Urine. 207 from a case where there may be but a slight departure from the normal condition, the band at F is replaced by a band nearer the red, when these reagents, caustic soda or caustic potash, are added; but ammonia causes its disappearance. The reason of this is, that in the latter case, febrile urobilin is present. When, therefore, the pigment which gives the band at F is isolated from healthy human urine, it should present the same spectroscopic characters as the urine containing it. Such is the case: for when normal chrome-yellow coloured urine is precipitated with neutral and basic acetate of lead, the precipitate extracted with alcohol acidulated with sulphuric acid, the acidulated alcohol containing the pigment ‘separated by filtration from the lead precipitate, the fluid diluted with water and shaken with chloroform in a separating funnel, the chloro- form separated, and then distilled off, a residue is left, which is a brown-yellow, amorphous, nitrogenous pigment, soluble in alcohol, ether, chloroform, and benzol, also in acids, and which gives in its various solutions the same band that was seen in the urine, and altered in the same manner by reagents, as it was altered in that fluid. While febrile urobilin gives a sharp black band at F of intensity a, the band of normal urobilin is less marked at its edges, and is less shaded than the former. Its alcoholic solution shows the band well, and when this is treated with caustic soda, caustic potash, or ammonia, it disappears. Sometimes its disappearance may not be complete, and in that case, the pigment which I named urolutein in my former paper may be present. The pigment may sometimes appear more brown than brown-yellow in colour, and in that case it shows a tendency to imitate febrile urobilin in its behaviour with the caustic alkalies, for on their addition a feeble band may be noticed nearer the red than the original band. More especially is this likely to occur if the acidulated alcohol contains too much acid, or if the fluid be left too long in the separating funnel.* As a general rule, the more the colour of the pigment approaches to brown, or brownish-red in colour, the more does it resemble febrile urobilin in its characters. The colour depends upon the amount of oxidation to which it has been subjected in the body, as well as on its artificial preparation, as I shall endeavour to show afterwards. The band of normal urobilin is shown in Chart I, sp.:2. As a general rule, it extends, when examined in a suitable depth of alcohol, from wave-length 507 to wave-length 482. While alcoholic solutions of febrile urobilin are red in colour, and become yellow with caustic alkalies, the alcoholic solution of this pigment becomes redder with caustic soda. This is well marked when the alcoholic solution is treated with sodium amalgam, for after the introduction of this sub- * Because in that case the chromogen of febrile urobilin is oxidised into febrile urobilin. (Vide infra.) 2 Q2 Dr. C. A. MacMunn. Researches into the [Dec. 16, Chart I. 30 40 50 tee i i a ql - - = 5 ity ay T it if alt Hf : ‘ih li: 2 ‘ll Wn ? : a] % \ - be iu I Hi i ia i i 1880. ] Colouring-matters of Human Urine. 209 stance, the colour of the fluid becomes orange-red, and general absorption of the violet end of the spectrum takes place. This re- action at once shows a likeness between this pigment and choletelin, but even a more striking likeness is exhibited by the action of chloride of zinc, for when the pigment in its alcoholic solution is treated with chloride of zinc, the colour of the fluid at once gets redder, and it then shows a narrow and sharp band nearer the red end of the spectrum. The edge of this band nearer the red is the more abruptly shaded, that next the violet shows a gradually decreasing shading. Thus, taking an actual experiment :-— Band before zinc chloride, wave-length 504 to wave-length 484. Band after zinc chloride (sp. 3). Dark part of band, wave-length 516 to wave-length 501. Feeble shadow up to wave-length 484. If, now, caustic soda be added to the fluid treated by zine chloride, the precipitate being dissolved in an excess of that reagent, the fluid becomes yellow, and the same band as that got by treating febrile urobilin is then seen, of intensity 6. Now Heynsius and Campbell* found that choletelin acted in the same manner, for it could not be made to give this band 6, until it had been first treated with zinc chloride. The following differences collected together were found to exist between normal and febrile urobilin :— (1.) The acidulated alcoholic extract of the lead precipitate is lighter in colour than that of febrile urobilin. (2.) The chloroformic solution is of a yellow colour, and when poured on a Berlin dish it is seen to be slightly reddish where its edge touches the dish. The same solution of the febrile urobilin is red. (3.) The absorption-band in the urine, in alcoholic solutions and ix chloroformic solutions, has less well-defined edges and is less shaded than that of febrile urobilin. (4.) The band at F is made to disappear by means of caustic alkalies, while it is replaced by another in the case of febrile urobilin. (5.) The pigment is yellow-brown, febrile urobilin being reddish- brown. When sodium amalgam is put into an alcoholic solution, as previously mentioned, the colour becomes orange, but by continuing the action longer, then acidulating with hydrochloric acid and shaking with chloroform, and evaporating off the chloroform, I obtained a brownish pigment, which, when dissolved in alcohol and treated with caustic soda, gave a band on each side of D (Chart I, sp. 4). Now, it is a remarkable fact, that I subsequently observed the same bands on * “Centralblatt f. d. Med. Wiss.,” 1872, p. 696. 210 Dr. C. A. MacMunn. “Resedpolies into the [Dec. 16,. treating febrile urobilin, obtained from a case of pleurisy, with caustic soda (Chart I, sp. 17), and I think this points to the conclusion that normal urobilin has a tendency to pass, when reduced by sodium amalgam, into the condition of febrile urobilin.* Moreover, these bands indicate the source of the pigment in the economy, as similar: bands are seen in the spectrum of a pigment obtained from gall-stones (Chart II, sp. 2), in that of the alcoholic extract of bile-colouring matter, and also in that observed when hematoin was reduced by means of sodium amalgam in the neutral state at the ordinary tem- perature, and the fluid examined at an early stage of the reaction. A faint band covering D may sometimes be seen in solutions of normal urobilin, but I have not yet determined upon what conditions its presence may depend. (See, however, Chart II, sp. 15.) It can only be seen in deep layers of alcoholic solution. The amount of normal urobilin in urine is small, but what I have been able to obtain after about thirty experiments will suffice to establish its identity. This pigment has, up to the present time, been confounded with febrile urobilin, but it will be seen that it is quite a different body. Before I had succeeded in isolating it, I had concluded that it was identical with febrile urobilin, and since this normal urobilin is iden- tical with choletelin, and since the latter pigment is produced by oxidation from bilirubin, I had concluded that febrile urobilin was. produced by oxidation. It would appear that febrile urobilin, although it may represent an intermediate stage of the oxidation of bilirubin, is capable of being produced by reduction of choletelin, and therefore of normal urobilin, and also of a similar body produced by the oxidation of hematoin by peroxide of hydrogen. We may conclude that febrile urobilin is the same body as that obtained by Maly, and which he called hydrobilirubin, but that the present pigment is an entirely different body, and is produced by oxidation. But there is another body present in urine which is capable of passing into the condition of febrile urobilin when strong oxidising agents are made to act on the urine, in fact, it may be accepted as an established truth, that the chromogen of febrile urobilin exists in normal urine. Disquet believes that it is this body which furnishes urobilin when urine is treated with acids, and that it is oxidised in the presence of chloro- form into that body. Such may be true in some cases, but not in all, as the following experiment will show. When a stream of chlorine is passed through perfectly normal urine, or when this fluid is treated with permanganate of potassium, bromine in aqueous solution, or ozone, the colour soon changes to yellowish-red, and a black band is seen at F. When caustic soda is added after such treatment, this * Again, they may be seen when xormal urobilin has more of a brownish tinge, by treatment with caustic soda alone. + “Chem. Centr.,” 1878, s. 711. 1880. | Colouring-matters of Human Urine. Zink band is replaced by another nearer the red end of the spectrum, as in the case of febrile urobilin. Now, from another part of the same urine, which has not been thus treated, we can, by precipitation with lead acetate, and subsequent treatment with acidulated alcohol and chloroform, obtain normal urobilin. It therefore appears that it is not by the oxidation of the chromogen of febrile urobilin* that normal urobilin is obtained, but that this body (¢.e., normal urobilin) is present in the urine as such, or part may be present as its own chro- mogen. That such is the case will appear to be likely, when I come to describe the artificial production of normal urobilin from hematin. Urohematin. A Pigment excreted im the Urine of a case of Subacute Rheumatism.—The patient in whose urine this pigment occurred, was suffering from subacute rheumatism, and was taking 15 gers. of the salicylate of soda three times a-day. This pigment is of great interest as it can be prepared with ease artificially from hematin; and as it appears to be incapable of production from bilirubin, I have named it urohematin. The urine was a dark reddish-yellow colour, but did not contain blood or bile pigments as proved by appropriate tests. It gave a black band 63—74, or wave-length 507 to 480; with caustic soda, this band was replaced by another of intensity £ or y, from wave-length 513 to 491. No other bands were noticed in the urine itself. 1,000 cub. centims. of the urine were taken and precipitated with neutral and basic acetate of lead, and afterwards treated in the same manner as that already described,f for the isolation of normal urobilin. The chloroformic solution gave the remarkable spectrum seen in Chart I, sp. 6, and was the colour of dark golden sherry. Ina thinner jayer another band, «, made its appearance, reading wave-length 507 to 484. (Cf. sp. 8.) When the chloroform was distilled off, the residue was seen to be a dark-brown colour, and was soluble in alcohol, giving a red solution, and sp. 7, Chart I, and sp. 8. Ammonia did not cause the disappearance of the band at F when added to the alcoholic solution, but acted like caustic soda, namely, by causing another band, nearer the red than was the original one at F, to appear. Caustic soda made the fluid orange in colour, and shifted some of the bands very slightly, as shown in Chart I, sp. 9, but the replace- ment of that at F was well marked, sp. 10. * It is this chromogen which becomes oxidised when urine begins to decompose, so that stale healthy urine may contain febrile urobilin as such, and give its spectrum. t+ The acidulated alcohol extract gives almost the same spectrum as that got by treating artificially prepared normal urobilin, reduced by means of sodium amalgam, with sulphuric acid. (See sp. 5, Chart I, and cf. sp. 11, Chart I, and sp. 12, Chart I, and Chart ITI, sp. 17.) 212 Dr. C. A. MacMunn. Researches into the [Dec. 16, The pigment was slightly soluble in ether and in benzol, but insoluble in bisulphide of carbon. Hydrochloric acid and water dissolved the pigment completely, and a different spectrum was then seen (Chart I, sp. 11). Strong sulphuric acid dissolved the pigment, forming a red solution, giving sp. 12, Chart I. Permanganate of potassium did not seem to affect the spectrum, but peroxide of hydrogen seemed to remove the feeble bands, leaving a shadow from wave-length 584 to 567 and a band, a, wave-length 507 to 482. Sulphurous acid made the alcoholic solution lighter in colour, and gave in deep layer almost the same spectrum as with sulphuric and hydrochloric acids; and in a thinner layer, the band at F was the same as before its addition. Hyposulphite of sodiwm did not affect the spectrum. When the alcoholic solution was treated with sodium amalgam,* its reddish-brown colour changed to pale yellow after fourteen hours’ action, and it then gave sp. 13, Chart I. When this yellow fluid was cautiously neutralised, and then slightly acidified with hydrochloric acid, it became redder in colour and then gave sp. 14, Chart I, in a suitable depth. When the fluid treated by sodium amalgam, and subsequently hydro- chloric acid, was treated by permanganate of potassium, the band at F was made fainter, and did not appear to be replaced by another when caustic soda was added. This pigment was darker brown than febrile urobilin, which has a reddish-brown colour, and it was evidently nearer to acid hematin than the latter pigment. Its affinity to the latter pigment was shown by the way in which its band at F was affected by caustic soda, but by the way in which that band was affected by ammonia it was seen to be different. | By the action of zinc and sulphuric acid on acid hematin, I have succeeded in obtaining the same pigment (as will be described further on), and the solutions of the artificially prepared pigment gave the same spectra as those of this one, band for band, and the spectra of its various solutions were altered in the same manner as those of the present one by reagents. It would therefore appear that the various bands seen in solutions of urohematin are all due to one pigment, and not to the presence of impurities. Urobilin, from the Urine of a case of Pleurisy, probably due to Tuber- culosis.—There was but slight effusion into the pleural cavities; the temperature of the patient was 101° F. The urine was reddish-yellow in colour, contained neither bile or blood, and gave a black band at F, * Cf. the action of sodium amalgam on hematoin, infra. 1880. | Colouring-matters of Human Urine. 213 which was replaced by another one less shaded and nearer the red when caustic soda was added. 360 cub. centims. of the urine were precipitated with neutral and basic acetate of lead and treated as before. The acidulated alcoholic extract of the lead precipitate gave in deep layers no bands in red or orange. This alcohclic extract was red in colour. In shallow layers a black band was seen at F (Chart I, sp. 15 and sp. 16). The chloroformic solution was reddish-yellow and gave a black band at F',* and a feeble shadow extending for about the breadth of the band itself on its redward side. In deep layers no other bands could be seen. The black band « read from wave-length 501 to 482. The pigment left after the evaporation of the chloroform was reddish- brown in colour, and behaved like febrile urobilin as to solubility. Alcohol dissolved it, giving a reddish-yellow solution, which with caustic soda became perhaps slightly redder, and it then gave in deep layers sp. 17, Chart I, and in shallow sp. 18. These two bands at D were seen when normal urobilin was treated with sodium amalgam, as already referred to. (Vide supra.) With chloride of zinc another band appeared nearer the red in the position of that produced by caustic soda. This pigment did not give the same characters as normal urobilin, nor yet did it give exactly those of febrile urobilin. From the appearance of the bands near D with caustic soda, and taking into consideration the fact that these bands were noticed when normal urobilin was reduced with sodium amalgam, I believe the conclusion follows that this pigment was less oxidised than normal urobilin and less reduced than febrile urobilin. I have selected this pigment to show that the statement made in my former paper was correct, and that urobilint appears capable of existing in different states of oxidation. J have come to the conclu- sion that the greater the number of feeble absorption-bands noticed, the less the oxidation to which the pigment has been subjected in the body. Asa type of a pigment which has been produced by reduction only, | may refer to urohzmatin. Preliminary Huperiments on the Oxidation of Bile Pigments—In attempting to trace back normal and febrile urobilin to their origin, one naturally begins with bilirubin; consequently my first experiments were made on solutions of bilirubin, obtained by treating human bile with alcohol to precipitate the mucus, and then, after filtration, shaking with chloroform. I was not aware that I was dealing with solutions which might also have contained urobilin; in fact, I had come to the opposite conclusion, since such solutions failed to give a band at F. But when one considers that, even in spite of the absence * It was noted that the shading on the redward side of the band at F was only seen in chloroformic solutions. + This remark applies to pathological pigments more especially. 214 Dr. C. A. MacMunn. Researches into the [ Decry: of that band, urobilin might be present—for its band is invisible in slightly alkaline or neutral solution, and even after shaking with chloroform it may still be invisible until after an acid has been added —the conclusion follows that what has been supposed to be due to the transformation of bilirubin into urobilin may, after all, be nothing more than the gradual appearance under oxidation of the band of a pigment already existing in the solution. The behaviour of even impure solutions such as these is, however, very instructive. When a chloroformic solution is put into a stoppered bottle, so as to fill it about one-third, and the bottle is shaken from time to time, the fluid gradually gets light in colour. The general absorption of the violet end of the spectrum characteristic of bilirubin gradually gives way to an interesting special absorption, which is characterised by the appear- ance of a band on each side of D, which is soon followed by the appearance of one at F. Then the former bands fade gradually away, leaving the band at F. This change was found to have been com- pleted at the end of three weeks, and the colour of the fluid was then a pale brownish-yellow with transmitted daylight. The same series of changes in the spectrum accompanies the play of colour got by the action of nitric acid on bilirubin, and at the penultimate stage of the reaction, at the brown-yellow stage, we can isolate the pigment giving the band at F. But if the reaction be allowed to go on further, the ~ fluid becomes almost colourless, and no longer can the band at F be seen. Isolated at the penultimate stage, the pigment is found to be choletelin, but it is evident that if the bilirubin thus treated contained urobilin, accurate inferences cannot be drawn from the characters of the pigment isolated, as it might be not only an oxidised pigment derived — from bilirubin, but also a decomposition product of urobilin. Preparation of Pure Bilirubin.—Accordingly, it became necessary to procure pure bilirubin, which was done according to the directions given in the excellent ‘‘ Handbook for the Physiological Laboratory ” of Professor Burdon-Sanderson. Brown human gall-stones were powdered, extracted with ether, the residue boiled with water and treated with diluted hydrochloric acid. After washing and drying, the mass was boiled with chloroform; the chloroform distilled off over the water- bath; the residue treated with absolute alcohol. It was then treated with ether and alcohol repeatedly, and again dissolved in chloroform, from which it was precipitated by absolute alcohol. The pigment thus obtained was an amorphous orange-coloured powder. It is not possible in the limits of this paper to describe all the reactions and the spectra of the solutions obtained by this treatment of the gall-stones, so that I shall only refer briefly to them as they bear upon the subjects discussed here. The first ether extraction of the gall-stones gave two bands, which are evidently those of lutein— y from wave-length 482 to 469, and 6 from wave-length 459 to 442. 1880. | Colouring-matters of Human Urine. 215: The hot water extraction of a brownish colour gave a band, 6, from wave-length 507 to 486. The acidulated water also gave a faint band in the same part of the spectrum. The alcoholic extract gave a band on each side of D, which latter were evidently similar bands to those: noticed in solutions of the urobilin of pleurisy treated by caustic soda, or in solutions of normal urobilin treated by sodium amalgam, and in the intermediate stage of Gmelin’s reaction, and in the alcoholic extract of human and sheep-bile pigments, and which can be prepared arti- ficially by the action of sodium amalgam, 7m the cold, on solutions of hzematoin (when the pigment has been separated in the neutral state). This alcoholic solution was of a red colour with transmitted light in deep layers, while it was yellow in thin layers. One band, y, extended from wave-length 620 to 592, the other, 6, from wave-length 585 to 569, sp. 2, Chart II. With ammonia this fluid gave the spectrum seen in Chart II, sp. 3. The occurrence of these latter bands shows that the gall-stones contained urobilin,* as similar bands are seen by similar treatment of urobilin when it is obtained from bilirubin by sodium amalgam, as will be referred to again. Action of Chlorine on Pure Bilirubin.—The colours and changes of spectrum, similar to those which accompany Gmelin’s reaction, can be studied with great ease by passing chlorine, well diluted with oxygen (such as may be obtained in traces when black oxide of manganese is heated with chlorate of potassium), into a chloroformic solution. of pure bilirubin. In such a solution this reagent brought about the following changes in the colour and spectrum. The colour of the original solution being orange, it soon changed to :— 1. Greenish-yellow. 3 2. Sap-green (band before D, 625 to 598 wave-length). 3. Dark sap-green. 4. Green. 5. Bluish-green (band before D and traces of another after D). 6. Dark blue-green (band before D, and band from wave-length 588—546). 7. Indigo-blue (two bands, as before, and slight shading at F). 8. Indigo (band £, wave-length 620—598; «©, 588—555; a, 504—— 482). 9. Purplish-blue (band at F black ; ¢, fainter). 10. Lilac (band at F black, e almost gone, and # faint). 11. Port-wine red (8 fainter; a as before). 12. Reddish-yellow (a getting fainter, others gone). 13. Light yellow (no band to be seen). These appearances are represented in sp. 4 to sp. 10, Chart IT. When pure and dry chlorine, prepared in the usual manner and * 7,e., urobilin of bzliary origin. 216 Dr. C. A. MacMunn. Researches into the [Dec. 16, Chart II. 2 PL Ta | | | my = : iil ee |e . Ea 1880. | Colouring-matters of Human Urine. 217 purified by being passed into a solution of sulphate of copper, then strone sulphuric acid and, lastly, U-tubes containing chloride of calcium, is made to pass through a solution of bilirubin in chloroform dried by chloride of calcium for some days previously, the colour of the finid changes much more rapidly, but the changes in colour are accompanied by the same changes in the spectrum already noticed. On the Reduction of the Pigment present in the last stage to the con- dition of Febrile Urobilin by means of Sodiwn Amalgam.—lIt is evident that the changes which take place are similar to those which are seen in Gmelin’s reaction, that at the penultimate stage choletelin is formed, and that even at the last stage this is also further oxidised, as proved by the complete disappearance of the band at F. If chole-. telin be a fully oxidised bile pigment and febrile urobilin a less oxidised bile pigment we should be able to reduce choletelin back to febrile urobilin by the action of reducing agents. Accordingly, I proceeded to isolate the pigment of the yellow stage, having first filtered the chloroformic solution. It was then evaporated on the water-bath. The residue was a light yellowish-brown pigment, perfectly soluble in alcohol with a yellow colour. I could not see a band at F, for the pigment had been oxidised beyond the stage at which it gives this band. When a piece of sodium amalgam was introduced into the alcoholic solution the latter immediately became of a reddish colour. After it had acted for a short time the fluid was found to have the power of absorbing the violet end of the spectrum. When hydrochloric acid was added to the solution before the action of sodium amalgam no change took place, but when it was added to the red fluid after the action of the amalgam, it gave a black band, a, wave-length 506 to 481, sp. 11, Chart If. And when caustic soda was added until an alkaline reaction was developed a band, 6, appeared from wave-length 513 to wave-length 488. After the action of the amalgam had gone on for twenty-four hours the colour of the fluid was light yellow, and hydrochloric acid then produced a reddish fluid giving a band of intensity, a, from wave-leneth 502 to wave-length 478. But this pigment had gone just beyond the stage of choletelin, so that it became necessary to prepare that pigment. I thought that by preparing it by another method I should have additional evidence of the truth of the idea that it can be made to yield febrile urobilin by reduction, if the result should turn out favourably. Preparation of Choletelin from pure Bilirubin and its Conversion into: Febrile Urobilin—Some pure bilirubin, prepared as before, which gave only general absorption in the deepest and thinnest layers when dissolved in chloroform, was treated with a little caustic soda in a chloroformic solution and exposed to the air in an evaporating dish. After the lapse of twenty-four hours the residue was found to be sap- 218 Dr. C. A. MacMunn. Researches into the [ Dec. 16, green in colour, and it was then dissolved in alcohol. The solution was then filtered so as to catch any unchanged bilirubin. The filtrate was then seen to be a brilliant sap-green colour and gave only general absorption of the spectrum. It was now treated with strong nitric acid, and examined with the spectroscope. When the bands on each side of D had completely disappeared, leaving one at F of intensity B or y from wave-length 507 to 482, the solution was shaken with chloro- form in a separating funnel, and the reddish-yellow chloroform layer was separated off, and filtered. After evaporation of the chloroform, a brownish-yellow, or yellowish-brown amorphous pigment was left, soluble in the same solvents as normal urobilin. This pigment, when dissolved in alcohol, gave a yellow solution, and when looked at in a white dish, it had a slightly reddish tmge at the edge, where it touched the white surface of the dish, this being better marked in a chloroformic solution. The alcoholic solution gave a band of intensity 8, from wave-length 510 to 482, having ill-defined edges. When the fluid was treated with caustic soda, it became of an orange colour, and then general absorption of the violet end of the spectrum was noticed. Ina moderately deep layer, the dark shading commenced at wave-length 510. No band could be seen in a thinner layer. When caustic soda was added after the addition of zinc chloride, the reddish colour produced by the zine chloride became yellow, and I then per- ceived a feeble band from wave-length 516 to 488, but it was difficult to take the reading of this band. Sodium amalgam produced exactly the same effect that it produced with the pigment got by the action of chlorine, and the description given before will apply word for word to the present pigment. Action of Ozone on Pure Bilirubin.—Fearing that nitric acid might not have produced the pigment by oxidation, 1 planned an experiment by which ozone was made to act on bilirubin dissolved in chloroform. A Siemens induction tube* was made by taking two test-tubes, one larger than the other; the mner surface of the small tube was coated with tin-foil, and the outer surface of the larger one. They were kept from touching each other by four smali points of sealing-wax when one was placed within the other. All the space between the tubes was closed, except a hole at either end of the larger tube, into which a small glass tube was fastened. So that I had two concentric tubes, coated, the inner one on the inside and the outer one on the ont- side, with tin-foil, and containing a space between them through which oxygen could be passed. The coatings were respectively connected with the terminals of a Ruhmkorff’s induction coil, worked by a quart bichromate cell. When oxygen was then passed into one end of the space between the tubes, it came out ozonised through the small * “ Bloxam’s Chemistry,” 4th ed. (1880), p. 53. 1880. ] | Colouring-matters of Human Urine. 219 delivery tube at the other end. The latter was allowed to dip almost to the bottom of a test-tube containing a chloroformic solution of pure bilirubin. The oxygen was purified by being passed through strong sulphuric acid before entering the induction tube. After the ozone had been passed into the solution for fifteen minutes, it got slightly redder in colour, and it then gave a band covering D; no other band in shallow layer. The general absorption of the violet disappeared gradually, and a band 6 became detached at F, the colour of the solution becoming lighter at the same time. After longer action, the colour became still lighter, and the band still remained. As no other change took place, the action of the ozone was discontinued. The band at F 6 read from wave-length 515 to 482, and when hydro- chloric acid was added, it got darker, and gave the same reading, the colour of the fluid becoming red. But when caustic soda was added, the band read 507 to 480, and did not disappear. The pigment formed was therefore not choletelin, for its band should have dis- appeared with caustic soda, and if it had been febrile urobilin, it should have been displaced towards the red, instead of which it came nearer the violet. But although the pigment produced by the action of ozone on bilirubin was neither (apparently) choletelin nor febrile urobilin, yet its action was somewhat similar to other oxidising agents, in causing disappearance of the general absorption and the formation of a pigment giving a band at F. Action of other Oxidising Agents on Bilirubin, §c.—The action of per- manganate of potassium and peroxide of hydrogen on bilirubin is not easily studied, from the difficulty experienced in getting them to act on bilirubin ; for in chloroformic solution they will not do so, and when made to act on solid bilirubin, their action is confined to the surface, but on the whole, their tendency is to convert this pigment into choletelin. Peroxide of hydrogen, when added to bilirubin under- going oxidation, seems to advance the oxidation a stage, and then stops short. Although it acts with difficulty on bilirubin, there are other biliary pigments, such as those got in the alcoholic extract of human bile pigments, with which peroxide of hydrogen gives a play of colours, accompanied by the same alteration of spectrum which accom- panies Gmelin’s reaction; but this will be referred to again. Action of Sodiwn Amalgam on Pure Bilirubin.*—Bilirubin was sus- pended in water, and a piece of sodium amalgam introduced. After a few minutes a little of the fluid was taken and treated with hydro- chlorie acid, which caused the formation of brownish flakes; these were soluble in alcohol, forming a yellow fluid giving only general absorption. At the end of an hour, the fluid was brownish in colour, but lighter than it was at the end of half-an-hour. After nine and a * “ Ann. Ch. Pharm.,” clxi, 368; clxiii, 77, contain an account of Maly’s ex- periments on this subject. 220 Dr. C. A. MacMunn. ; Researches into the [Dec. 16, half hours it was yellow in colour, and minute particles of a brownish substance were seen suspended in it. This yellow fluid gave a band, 6, - from wave-length 513 to 488. It was then treated with hydrochloric acid, until acid in reaction, when it became reddish-brown. It was then filtered as brownish particles became separated by the action of the hydrochloric acid. The filtrate was a beautiful red colour, and gave a black band, a, 507 to 480; another reading in a thinner layer gave wave-length 501 to 482. When caustic soda was added to alkalinity another band, intensity 6, appeared from wave-length 513 to 486, the solution at the same time getting yellow in colour. The insoluble portions in the filter were a dirty green-brown colour, and gave, when dissolved in alcohol, an olive-coloured solution. In deep layers of this alcoholic solution there were seen two bands near D, the darker before D, the lighter on its violet side, and in shallow layers a dark band, «, was seen at F. (See Chart II, sp. 12 and 13.) Treated with caustic soda sp. 14 appeared. I may here mention that these same bands appear when the alcoholic extract of human bile- pigment is treated with caustic soda, and in gall-stones (as before referred to), sp. 3. It would therefore appear, that in addition to a body more closely resembling febrile urobilin, which the finid con- tained, an insoluble body was separated which appears to be identical with that kind of urobilin which occurs in bile and in gall-stones. Action of Caustic Soda and Hydrochloric Acid on Bilirubin.—As there is reason to believe that caustic soda alone changes bilirubin, and that hydrochloric acid oxidises it, I thought it would be interesting to compare the action of these reagents with that of the sodium amalgam. And in order to compare the action of the caustic soda, under the same circumstances as those which may be supposed to occur when sodium amalgam is used, I used a solid piece of pure ‘eaustic soda. When a solid piece of caustic soda is thrown into: water in which bilirubin is suspended, the fluid becomes orange, showing where it touches the dish a reddish tinge. (After five minutes’ action if a little of the fluid be taken out and treated with hydrochloric acid it becomes green in colour.) At the end of twenty minutes the fluid becomes green. If another piece of solid caustic soda be now put in and the fluid examined twenty-three hours after the commencement of the experiment, it is found to be a pale yellow- green colour, showing only general absorption of the violet end of the spectrum. When hydrochloric acid is added it turns red, quickly changing to brown, and giving before the spectroscope a black band, «, wave-length 507 to 482, and a feeble one, 6, 625 to 598. When this brown fluid is treated with caustic soda a shading appears over the violet end beginning at 516. It would therefore appear that the action of the caustic soda and subsequently hydrochloric acid is to oxidise the pigment just beyond the stage of febrile urobilin, and 1880.] Colouring-matters of Human Urine. 221 that it is premature to assume that urobilin is formed from bilirubin by reduction. It would further appear from this experiment, and from a careful study of Gmelin’s reaction, that febrile urobilin repre- sents an intermediate stage of oxidation of bile pigment. Identity of Choletelin and Normal Urobilin.—lt will be seen on com- paring choletelin with normal urobilin that they cannot be dis- tinguished from each other, being similar in colour, solubility, in spec- trum, and in the changes which their respective spectra undergo with reagents. But while choletelin is easily reduced back to febrile urobilin, normal urobilin is not easily reduced, because the chemical stability of the latter pigment is greater than that of the former. On the presence of a body having similar spectroscopic characters to those of Febrile Urobilin in Bile-——When human bile is treated with absolute alcohol to precipitate the mucus, &c., and shaken with chloro- form, the latter takes up a good deal of colouring matter, but as a general rule, gives only general absorption of the spectrum. From this fact I had come to the conclusion that the solution could not have contained urobilin, forgetting that the band of that pigment may be invisible when the pigment has been removed from a neutral or slightly alkaline fluid. The following experiments conclusively prove that a body is present in bile which gives the same spectroscopic characters as the body produced by the action of sodium amalgam on bilirubin ; and its presence can be proved, not only in the bile of man, but in that of the pig, ox, sheep, and probably in that of all animals possessing a gall-bladder. Urobilin in Human Bile.-—Here I shall principally refer to urobilin, leaving an account of the discovery of hematin in bile, until after the production of the urinary pigments from hematin has been dis- eussed. I have repeated the following experiments several times, but select one experiment as an illustration of the method adopted for the demonstration of the presence of urobilin. The bile was pro- cured from a case twelve hours after death; the gall-ducts and liver of the subject were free from disease. The bile was treated with absolute alcohol, filtered and shaken with chloroform, the latter separated off after having been allowed to stand some time, and filtered. This solution was orange in colour and gave no band at F. A feeble band could be seen in deep layers covering D, the violet end of the spectrum being shaded by the general absorption characteristic of bilirubin. The chloroform was distilled off over the water-bath, leaving a gamboge-yellow residue, which was extracted with alcohol, which was then filtered, leaving a green-yellow stain on the filtering paper. The residue left after the extraction by the alcohol was an orange powder consisting of almost pure bilirubin. The alcoholic solution was dark red when examined by transmitted gaslight, and a duller red with transmitted daylight, and with the WOU. KXXI. R O22 Dr. C. A. MacMunn. Researches into the [Dec. he. latter it was seen to be yellow with a greenish tinge in very thin strata. In deep layers it gave a band covering D, but in shallow layers one at F. (Chart IJ, sp. 15.) Treated with caustic soda it gave sp. 14,* Chart I, the colour of the fluid becoming light green- yellow. This is the same spectrum as that got by the action of caustic soda on bilirubin treated by sodium amalgam. It will be noticed that the band at EF becomes replaced under the action of caustic soda, by another of less intensity of shading and nearer the red end of the spectrum. Zine chloride produced a precipitate soluble in alcohol forming a green solution, and then the band at F was seen to be narrowed, and nearer the red; it produced a spectrum in other particulars like that vot by the action of caustic soda. Chart II, sp. 16. Hydrochloric acid produced a turbidity, changing the fluid to dark red, which became clear brown-red with more alcohol; this solution gave sp. 17 in deep layer, while in shallower layer sp. 18 appeared. Sulphuric acid produced a dark-red fluid, giving almost the same spectrum. From these observations it was quite evident that the same kind of urobilin was present as that got by the action of sodium amalgam on bilirubin. Urobilin was absent from the bile in a case of thrombosis of the portal vein, and this observation supports the view that it is formed in the intestine. : Urobilin in the Bile of the Pig.—This bile was golden-yellow, and was treated as in the case of human bile. The chloroformic solution was. yellow, and left a chrome-yellow residue, which was entirely soluble in rectified spirit, forming a yellow solution. This gave, in deep layers, general absorption, and in thin strata a band from wave-length 507 to- 482. Zine chloride produced a precipitate soluble in alcohol, and an abrupt shading commencing at wave-length 510. But in a thinner layer a band was seen detached in the usual position, but owing to the general absorption its violet edge was indistinct. When the alcoholic solution was treated with acetic acid a band, a, from wave-length 507 to 478 was visible, the colour of the solution being greenish-yellow. The alcoholic solution treated with caustic soda got pale yellow, and gave the usual band from wave-length 512 to 488. This observation afforded positive proof of the presence of urobilin in the bile of the pig. Urobilin in Ox-bile—This bile was brown in deep, but yeliow in shallow strata. It gave sp. 2, Chart III, which is of great interest, as. a similar spectrum can be produced artificially from hematin, to which I * This map is made to represent two spectra, as both were exactly similar (see explanation of Chart II). 1880. | Colouring-matters of Human Urine. Chart IIT. an | Ia 224 Dr. C. A. MacMunn. Researches inio the [Dec. 16, shall again refer. Hvery possible precaution was taken to exclude the presence of blood. When treated as in former cases, the chloroformic solution was golden-yellow, and gave sp. 3, Chart III. When the chloroform was evaporated, it left a yellow-brown amorphous residue, which was partially soluble in alcohol, forming an orange solution. This gave in a thin stratum sp. 4, Chart IJ]. When this fluid was treated with caustic soda it became light yellow-green, and then gave sp. 5 in a thin layer.* Chloride of zinc made the alcoholic solution orange-red, giving in deep layer sp. 6, and in shallow sp. 7. When this fluid, already treated by zinc chloride, was treated with hydrochloric acid, sp. 8, Chart III, was seen, the colour being light red. Ammonia acted in the same manner as caustic soda, except that the band at F could no longer be seen. Urobilin was, therefore, present in this case. Urobilin in Sheep-bile.—Its presence can here be demonstrated in the same manner, but as all the spectra are almost identical with those of ox-bile, I will not describe them. The band at F is affected in all these solutions of human, pig, ox, and sheep bile in exactly the same manner by reagents as in the case of febrile urobilin, but, by the action of ammonia and caustic soda, certain bands in red and orange appear, which, although they are present in urobilin prepared by sodium amalgam from bilirubin, are not always seen in the pigment got from urine. Again, it would appear from numerous observations that, while the biliary pigment is oxidised with comparative ease into choletelin, the urinary pigment requires much stronger oxidising agents to bring about that result. On the Artificial Production of a Pigment exactly similar to Uro- hematin (excreted in the Urine of Rheumatism) from Acid Hoemetin.— Hoppe-Seyler,¢ to whom physiological chemists owe so much, was the first who tried the action of tin and hydrochloric acid on hematin. He got a pigment which showed such striking resemblance to Maly’s hydrobilirubin that he came to the conclusion that the artificially prepared pigment was the same as Maly’s pigment, but he noticed that the pigment prepared from hematin gave a band before D and one between D and H, as wellasaat F. By the action of zine and sulphuric acid on acid hematin or hematoin, as it has been named by Professor Preyer, I have succeeded in obtaining a pigment which, when dissolved in various solvents, is found to be exactly similar to the pigment which I isolated from the urine of a case of rheumatism, and which I have taken the liberty of calling urohematin. It shows * Cf. Chart IJ, sp. 3, 14, and 16, &c. + “ Handbuch der Physiologischen- und Pathologischen- Chemischen Analyse,” Ath ed., p. 214, e¢ seq., and “ Spectroscope in Medicine,” p. 116. 1880. | Colouring-matters of Hi fants Urine. 225 a most remarkable series of bands, in addition to that at F. The experiment has been repeated several times, with an uniform result. The fresh defibrinated blood of the sheep is treated with alcohol and sulphuric acid (2 parts H,SO, to 35 alcohol) and filtered, more alcohol being afterwards added (if necessary) to help the filtration. This dark- red filtrate gives the spectrum of acid hematin, which is seen in sp. 9, Chart III, and which gives the bands of hzemochromogen (reduced hematin) with sulphide of ammonium. It is put into a narrow and deep beaker, some fragments of pure zinc and sulphuric acid being added in sufficient quantity to develop a reaction, and a gentle heat is applied to the water-bath over which the beaker is placed. When the action has ceased the fluid is filtered, when it is seen to have become of a much lighter colour. (Sp. 10.*) It is then put into a separating funnel, diluted with water, and shaken with chloroform. The chloroform takes up the pigment, forming a dark- red solution; on separating this off and filtering it, and then distilling the chloroform, a dark-brown pigment is left. It is soluble in alcohol, with a rich colour, and this gives sp. 11, Chart III, in a moderately shallow layer. (Compare 7 and 8, Chart I.) Ammoma slightly alters the position of the bands, when added to the alcoholic solution, bringing some of them slightly nearer the red end; narrowing and bringing the band at F' near the red, but not causing it to disappear. Caustic soda produces the same effect as am- monia, sp. 12, Chart III (colour of solution, orange). Zine chloride produces almost the same change, sp. 13, Chart ITI. (Cf. action on urobilin.) The chloroformic solution of this ee gives sp. 14, Chart ITI. On comparing these spectra with those of the urinary pigment, urohzmatin, it is seen that they are identical band for band, and the description of the reactions with other reagents given by that pigment will apply exactly to this one. On looking at Preyer’st map of “iron-free hematin” a likeness to the present pigment is noticed, but they are different bodies, and the action of sulphuric acid aided by heat had nothing to do with the result; for we can not only prove that a different pigment is produced under those circumstances, but urohematin can be prepared in a different manner, in which the influence of sulphuric acid aided by heat is completely excluded. If the solution of hematoin be prepared as before, and it is ce shaken with chloroform and water in a separating funnel, the chloro- form will take up the hematoin, for which I find it is a perfect solvent, and again leave it, after it has been distilled off, in a neutral state. * Cf. action of sulphuric acid on the natural pigment, Chart I, 12. It is pro- bably these bands that Hoppe-Seyler mentions. ¥ “Die Blutkrystalle,” Tafel I, 15. 226 Dr, C. A. MacMunn. Researches into the [Dec. 16, If this hematoin is then dissolved in alcohol and diluted with water, the solution put into a narrow and deep beaker (or better - in a flask), a piece of sodium amalgam added, and the whole gently heated on the water-bath, a change will be found to have taken place after some time. The colour gets much lighter, becoming at last yellow, and it then gives sp. 12, Chart III; this is seen to be the spectrum of urohematin prepared by the former method and treated in alcoholic solution with caustic soda. The fluid may then be filtered, the filtrate treated with sulphuric acid to acidity, when its yellow colour changes to orange-red. It is then (after acidi- fication) filtered, put into a separating funnel and shaken with chloroform ; this chloroformic solution is reddish and gives sp. 14, Chart III.* When the chloroform is distilled off a dark-brown pig- ment is left, which alcohol dissolves, forming a red fluid giving sp. 11, Chart III. Treated with caustic soda it gets orange (i.e., less red) and gives sp. 12, Chart III. Ammonia produced the same effect, and its behaviour with other reagents shows that this is the same pigment as that obtained by the action of zinc and sulphuric acid on heematoin. It is, therefore, certain that by the action of reducing agents on heematoin a pigment can be prepared, identical with a pigment which can be obtained from urine in certain diseased conditions, and the name urohematin best expresses the origin of that pigment. Artificial production of a Pigment from Acid Hematin by Oxidation, indistinguishable from Choletelin and from Normal Urobilin.—The identity of choletelin and urobilin of health has already been proved in this paper. I have now to describe a method by means of which a pigment, which cannot be distinguished from either, can be procured from acid hematin (hematoin). So far as I know, this experiment has never been described. A solution of acid hematin having been prepared as before, it is treated with peroxide of hydrogen until it changes colour. The red colour first seems to get slightly darker, but it soon changes to brown- yellow ; and then a curious change is seen to have taken place in the spectrum. All the bands of acid hematin have gone, and instead, a band £, or y, isseen between green and blue (sp. 15, Chart III), wave- length 507 to 484. This change can be produced by treating the hematoin in the original acid solution, or when separated in the neutral state by means of chloroform, with the peroxide ; but if the latter method be adopted we must slightly acidulate again before the pigment can be isolated. The former method is, of course, the easier. If this solution of peroxidised acid hematin be put into a funnel and shaken with chlo- roform, the latter becomes reddish-yellow, and when separated and * Under certain unknown conditions another feeble band in red may be noticed. 1880. | Colouring-matters of Human Urine. rapa evaporated off, it leaves "a brown-yellow amorphous pigment. It is soluble in the same solvents as choletelin and normal urobilin. The chloroformic solution appears yellow on a white dish, giving a reddish tint where the fluid touches the white dish, and it gives a band, 6 or 7, from wave-length 510 to wave-length 484, with ill-defined edges. Alcohol* dissolved the pigment, forming a yellow solution giving a band, y, from wave-length 507 to 482. When this yellow fluid was treated with caustic soda it became orange, and gave, in deep layers, general absorption of the violet up to wave-length 554. In shallow layers no band was visible. Zinc chloride caused the fluid to assume an orange colour, and then the spectrum was shaded up to wave-length 538. In a thinner layer a band became detached (though this was not easily seen) from about wave-length 526 to o01 (?). When the fluid treated by zinc chloride was treated with caustic soda, the orange-coloured fluid became yellow, and a feeble shadow from wave-length 513 to 488 was just visible. Re-acidified after treatment with caustic soda a black band came back in the original position. The above characters are sufficient to establish the identity of this pigment with normal urobilin and with choletelin; but its action with sodium amalgam completely proved the truth of this supposition. Artificial Production of Febrile Urobilin from the Pigment produced by Oxidation of Hematoin—When this brown-yellow pigment is dis- solved in alcohol, it gives a yellow solution; when it is diluted with water and sodium amaleam introduced the colour soon becomes orange. After longer action, especially when a gentle heat is applied, the fluid again becomes paler, until at last it assumes that of pale sherry. {See sp. 16, Chart III.) When sulphuric acid is added to acidity, the fluid becomes orange-red, and then three bands are visible, one before D, one between D and H, and a black one at F,sp.17. But if imstead of using strong sulphuric acid, it is added in the pro- portion of two parts acid to twelve alcohol, and the fluid is then shaken with chloroform, the latter takes up the pigment forming a red solution, which appears yellow in thin layers. On evaporating the chloroform, a reddish-brown pigment is left. This dissolves in alcohol with a red colour, and gives in deep layers no bands near D, but in shallower ones a black band at F. It will, therefore, be seen that strong sulphuric acid has the property of so changing the chromogen of the reduced pigment, as to produce two bands near D, as wellas that at F. I believe that this may account for the presence of certain feeble bands near D, seen in solutions of febrile urobilin. feces Eroc: Hoy. Soc,” vol. 31, p. 26.) If to the alcoholic solution of the pigment of a red colour, and * Ordinary rectified spirit. 228 Dr. C. A. MacMunn. Researches into the [Dee. 16, giving the black band at F’, caustic soda be added, it becomes yellow in colour, and then gives a band, 6, from wave-length 513 to 488. In deep layers two other feeble bands are seen on the violet side of D (Chart IIT, sp. 16*). When the alcoholic solution is treated with zine chloride and allowed to stand a few minutes, a narrow band is seen, which is exactly the same band, as regards position and shading, as that seen when solutions of febrile urobilin are treated with zinc chloride. It would, therefore, appear that by the action of sodium amalgam aided by heat, a colourless, or almost colourless, solution has been obtained, which under the influence of sulphuric acid becomes orange- red, and gives all the characters of febrile urobilin. The original body acted upon with the sodium amalgam being identical with choletelin and with normal urobilin. On the Action of Decolorised Bile on Heemoglobin.—Seeing that the urinary pigments, at least such as are recognisable by means of the spectroscope, can be produced with great ease from hematin, I was led to think that perhaps hematin might be present in the bile, and asa preliminary step to this inquiry I tried the effect of the colourless constituents of the bile on hemoglobin. Ox-bile was treated with rectified spirit, filtered, then well shaken with animal charcoal in a flask, and again filtered; as this filtrate showed some general absorption of the violet, it was again decolorised. It was then evaporated almost to dryness on the water-bath, and diluted with water; the taste of the solution was exceedingly bitter; it was alkaline, and gave Pettenkofer’s reaction and its spectrum. To this fluid 3 cub. centims. of the fresh defibrinated blood of a cat were added. The mixture was put into a hot air-bath, and the bath heated to 110° F; the mixture being stirred with a glass rod from time to time. It soon got darker in colour, and then gave the spectrum of methemoglobin. ‘The tempera- ture of the bath was then raised to 180°, and the fluid got still darker in colour. After longer action it became a fine crimson, and then gave a band covering D, and one at F, sp. 18, Chart III. After longer action no further change took place. The same body can be produced by the action of caustic soda in alcohol on hemoglobin. Action of Caustic Soda in Alcohol on Blood—When fresh blood (defibrinated) is treated with alcohol and caustic soda, the colour changes to dark red. If the blood so treated contain oxidised heemo- globin, we get a band at D, and a feebler one at F; but if it contain reduced hemoglobin, and the reagent is added with exclusion of air, hemochromogen is formed at the same time. The spectrum got by the action of the reagent on oxidised hemoglobin is evidently hematin, * Another (doubtful) band may have been present in red, its centre at wave-length 625 if so, the reduced pigment was passing by reduction into urohzmatin, with which three of its bands are coincident. 1880. | Colouring-matters of Human Urine. 229 as it gives the bands of hemochromogen with sulphide of ammonia. A similar pigment may be obtained by isolating hematoin as described before, and treating the residue with alcohol and caustic soda, when the same spectrum is seen; but while the pigment obtained directly from oxidised hemoglobin is easily reduced to hemochromogen, the latter pigment is reduced with great difficulty. This alkaline hematin, whose spectrum is represented in Chart IIT, sp. 19,* is easily converted into acid hematin again, and thus may be the source of all those kinds of hematin from which the biliary and urinary pigments can be formed. Production of the Spectrum of Sheep-bile from this Pigment.—W hile by the influence of oxidising agents such as peroxide of hydrogen and permanganate of potassium, this body yields apparently the same pig-- ment as hematoin yields, it gives with sodium amalgam in the cold, and with brief action the spectrum of sheep or ox bile, sp. 20, Chart III. It wants, however, one band in the red, but that also can be made to appear by gentle oxidation with peroxide of hydrogen, and this band in bile only appears after that fluid has been exposed to the: air for some time. (Cf. Chart IV, sp. 2, and Chart III, sp. 2.) When this reduced brownish-red solution was treated with hydro- chloric acid, it gave a spectrum very like that got by treating the bile. pigments of the sheep with the same reagent ;{ but in order to compare the action of reagents on the respective fluids, it will be necessary to: isolate the pigment giving this spectrum from sheep-bile, which has not yet been done. When the solution giving the above spectrum is treated with sulphide of ammonium the bands of hemochromogen appeared. Consequently, if sheep-bile contains this kind of hematin, it should also yield the bands of that substance with sulphide of ammonium. Hematin in the Bile of the Sheep.—Perfectly fresh bile, which did not contain blood, and which gave sp. 2, Chart IV, had a few drops of acetic acid added to it, but as this was not sufficient to precipitate the mucus when added in such small quantity, alcohol also was added. The fluid, after filtration, was shaken with chloroform and water. The chloroformic solution, after separation and filtering, had a brown colour, with a slightly greenish tinge, giving sp. 3, Chart IV. The chloroform was evaporated off, leaving an olive-brown residue. This, dissolved in alcohol, formed a green-brown solution, giving sp. 4,. Chart IV. When sulphide of ammonium was added to this fluid, the * The difference in position of band near D in 19 and 20 is accounted for when we remember that in one case we are dealing with an alcoholic, and in the other with a syrupy aqueous solution. + The bands are not coincident with those of 2, because in one case bile, and im the other alcohol, is the solvent for the pigment. (See 2, 3, and 7, Chart IV.) t “Spectroscope in Medicine,’ Chart IT, sp. 9. 230 Dr. C. A. MacMunn. Researches into the [Dec. 16, bands of hemochromogen appeared, Chart IV, sp. 5 and sp. 6.. This experiment has now been repeated several times, and I believe that the conclusion may be accepted, that sheep-bile contains hematin, and similar to that which can be obtained artificially in the manner already described.* Chart IV. Hematin in Human Bile.-—The golden-yellow coloured bile obtained twelve hours after death, from a case of meningitis, and which gave only general absorption, even in thin strata, was treated with a little acetic acid, diluted with water, and shaken with chloroform. The * The band covering D is not, of course, due to heemochromogen, but probably to -a bile pigment, as referred to before. , 1880. | Colouring-matters of Human Urine. 231 residue had a slightly green tinge, and after extraction with alcohol, the alcoholic solution was seen to be a brownish-green colour, and gave the spectrum already described (sp. 7). When this solution was treated with sulphide of ammonium, sp. 8, Chart IV, appeared after it had stood a short time (the original is seen in sp. 7), the colour of the fluid changing to red. Ammonia had nothing to do with this result. It therefore appears certain that human bile also contains heraatin, but in less quantity than the bile of the sheep.* If the curious series of bands seen in sheep-bile are due to the pre- sence of hematin, it is probable that the bands seen in the red, orange, and green parts of the spectrum characteristic of the spectra of the bile of other animals, are also due to its presence. In the bile of the crow these bands are like those of the bile of the sheep and ox; in that of the guinea-pig the single band may be due to the darker band of heemo- chromogen ; those of the rabbit appear to be the bands of that sub- stance, and I have no doubt that the presence of hematin in the bile of these animals will be proved as easily as in the case of man and the sheep. Of course I do not include the band at F, as that is always due to the presence of urobilin. Action of Perowide of Hydrogen on the Alcoholic Extract of Human Bile Pigments.—W hen the brown-green alcoholic extract of the chloro- formic residue of human bile pigment (see sp. 7, Chart IV), and which was proved to contain hematin, urobilin (of biliary origin), and other pigments, was treated by peroxide of hydrogen on a white dish, the colour changed from brown-green to dark-green, blue-green, blue, violet, red, red-brown, and brown-yellow. At the violet stage three bands were visible, sp. 9, Chart IV ;¢ at the brown-yellow stage only one, that at F,sp.10. It was, therefore, evident that the mixture of pigments could be oxidised into choletelin with great ease. The Absorption Band of Serum.—The band at F in blood-serum has been said to be due to lutein;§ whether that substance is or is not present, there is evidence to show that an owidised bile pigment is that which gives the band, and I have come to the conclusion, from a careful examination of fresh blood-serum, obtained by letting the blood of the sheep clot spontaneously, and filtering the yellow serum, that it contains either choletelin or a substance like it. The serum gave sp. 11, Chart IV, which shows that it still contained traces of hemoglobin. The band at F y read from wave-length 504 to 480, it was therefore nearer the red than the band of lutein, and I could * As proved by the presence of first band of reduced hematin, the second being just visible and overlapped by general absorption. (See 8, Chart LV.) + See Chart II, “Spectroscope in Medicine.” { That at F will be represented by next spectrum, 10. § Maly believed he had detected urobilin in blood, but Hoppe-Seyler thought he had mistaken lutein for it. See ‘‘ Hand. der Phys. und. Path. Chem. Anal.,’’ loc. eit. Dae Dr. C. A. MacMunn. Hesearches into the [| Dec. 16, not, by any method, see the second band of lutein in violet. More- over, caustic soda and ammonia which intensify the band of lutein, caused this band to disappear; and when zinc chloride in very small quantity was added after the caustic soda a precipitate fell, but when this was separated from the fluid, I thought I could perceive a faint band from wave-length 516 to 488. If the white of egg is compared with this, as I find that it contains some of the lutein of the yelk, we see two bands distinctly, and that nearer the red is decidedly darkened by both caustic soda and by ammonia; moreover the first lutein band of the yelk in alcohol read from wave-length 496 to 478. (Lutein itself, even if present, may also be formed in the liver, as I have found it in gall-stones (vide antea), and a pigment giving its spectrum appears to be formed by the long-continued action of caustic soda on the alcoholic extract of the pigments of sheep bile, sp. 4. Thus, the first action was to give sp. 12, Chart IV, but after half-an-hour sp. 13 appeared, the other bands having faded away.) I therefore conclude that the absorption-band of serum is due to a body which is produced by the oxidation of the bile pigments, and which is on its way to be excreted by the kidneys.* Summary and Conclusions. (1.) That normal human urine contains a body as such, which is apparently identical with choletelin and with the body produced by the action of peroxide of hydrogen on acid hematin. (2.) That normal human urine contains the chromogen of febrile urobilin, which can be prepared artificially by reduction of choletelin, and of the body produced by oxidation from hematoin. (3.) That human, ox, sheep, and pig bile contain a kind of urobilin, which differs in some respects from that excreted in urine, and that they also contain hematin. (4.) That it is highly probable that all the constituents of bile colouring matter are produced from hematin by reduction. (5.) That the hematin present in bile is probably due to the action of the bile acids on hemoglobin. (6.) That all the colouring matters of bile, including hematin, urobilin of biliary origin, bilirubin, &c., are oxidised into choletelin, and that there is evidence to show that blood-serum contains this body, which is on its way to be excreted by the kidneys. (7.) That the absorption-bands seen in the bile of various animals are due to the presence of hematin and urobilin of biliary origin. (8.) That a pigment excreted in the urine in certain pathological conditions is derived from hematin by reduction, as it can be obtained by reducing acid hematin with zinc and sulphuric acid, and also by * Neubauer and Vogel (‘‘ Guide to Analysis of Urine,’’ American edition, 1879, p- 64) think this band is due to urobilin. 1880. ] Colouring-matters of Human Urine. 233 means of sodium amalgam; that it is not febrile urobilin, and as it is derived directly from hematin it is best named urohzmatin. (9.) That the urobilin of bile is produced in the intestine. (10.) That the urobilin of bile may, in certain states of the system, appear in the urine, but that under normal conditions it is oxidised into choletelin in common with the other biliary pigments, and comes to the kidneys as choletelin, while a part may pass into the urine as such, but a part becomes reduced in the kidneys into the chromogen of febrile, and perhaps also into the chromogen of normal urobilin; the former by strong oxidising agents passing into febrile urobilin, and the latter by the action of weaker oxidising agents into normal uro- bilin. (11.) That many of the colouring matters of urine have been pro- duced, by the action of the reagents designed to separate them, on these chromogens. (12.) While most of the uriary pigments are traceable back to the bile pigments,* there is evidence to show that some of them are derived from hematin directly, and pigments derived from that source may entirely replace the normal pigments. A diagram will clearly explain the connexion, which appears from ‘this research to exist between all these pigments :— Hemoglobin. | il Hee seh ule Bilirubin. Alkaline Heematin. Acid Hematin. Pigment of sheep bile. 2 S &, = aie qua 2 = “7. 4 eye = Z, _e = Bilary Urobilin. On g = (S) B ale E | = = Choletelin. Choletelin. Choletelin. he Nal. 3 va Aetna) Choletelin or normal Urobilin. «:-,-Chromogen of febrile Urobilin. 34 ae wi 4. Chromogen of normal Urobilin. O Als 5 | Normal Urobilin. * Bilirubin, biliverdin, &e. 234 Dr. C. A. MacMunn. Researches into the [Dec. 16, There appears to be one point of difference between normal urobilin and choletelin and the pigment obtained from hematoin: that is, that while chloride of zinc produces a narrow band nearer the red with an alcoholic solution of normal urobilin, it does not produce that band with the latter pigments until they have been slightly reduced with sodium amalgam ; this would show that some change (reduction) has taken place in the normal urinary pigment during its passage from the blood into the urine. EXPLANATION OF CHARTS. The accompanying charts were mapped from the microspectroscope provided with an accurately divided photographed scale, andthe scale at the top of each chart is that of the instrument. Accompanying these charts is a table giving the value of each division of the scale in wave-lengths. I have adopted this plan in order to avoid haying two scales adapted to the charts; and a scale of wave-lengths would not be accurate adapted to maps drawn this size. Cuart I. Spectrum 1. Solar spectrum. ss 2. Normal urobilin in alcohol. 3 3. The same treated with chloride of zine. - 4, Action of sodium amalgam on brown-yellow normal urobilin, and of caustic soda on brown urobilin. Bs 5. Acidulated alcoholic extract of urohematin from urine of rheumatism ; deep layer. 6. Chloroformic solution of the same pigment. 7. Alcoholic solution of ditto. 8. Shallow depth of the same. 9. Deep Jayer of alcoholic solution (7) treated with caustic soda or ammonia. » 10. The same, shallow depth. » 11. Urohematin in alcohol, treated with hydrochloric acid. », 12. The same treated with sulphuric acid. ,, 13. The same with sodium amalgar », 14. The pigment (acted on by amalgam) with hydrochloric acid. » 15. Acidulated alcohol extract of pigment got from the urine of a case of pleurisy; deep layer. 5 16. Ditto, shallow layer. » 17 and 18. The alcoholic solution of this pigment treated with caustic soda, in deep and shallow layers. Cuart II. Spectrum 1. Solar spectrum. vs 2. Alcoholic extract human gall-stone. i. 3. The same treated with caustic soda or ammonia. ss 4. Chloroformie solution of bilirubin. a 5, 6, 7, 8, 9, 10. Action of chlorine on this solution. , 11. The pigment of stage represented in sp. 10 treated with sodium amalgam and afterwards hydrochloric acid. - 1880.] Colouring-matters of Human Urine. 235: Spectrum 12. Pigment got by action of sodium amalgam on bilirubin dissolved in bP) alcohol, and precipitated by means of hydrochloric acid.* 13. The same, thin layer (the band at F is shown rather tvo dark.) 14. The same treated with caustic soda.+ 15. Alcoholic solution of chloroformic residue of human bile pigments, deep layer ; in a thinner layer another band is seen wave-length 504 to 480. 16. Ditto, treated with zine chloride. 17. Ditto, treated with hydrochloric acid. 18. Thin layer of the same. : Compare 2, 7, 12, and 17, and 3, 14, and 16. Cuart IIT. Spectrum 1. Solar spectrum. 3 2. Ox-bile. . s 3. Chloroformic solution pigments of ox-bile. (Compare 2 and 3 with 20, infra.) 4, Pigments of ox-bile in alcohol. 5. The same treated with caustic soda. 6. Action of chloride of zinc on alcoholic solution (4). 7. The same, shallow depth. 8. The same (7) treated with hydrochloric acid. 9. Hezmatoin (acid hematin) in alcohol. 0. Hematoin treated with zinc and sulphuric acid and filtered. (Compare Chart 1, 11, 12, 14.) 11. The isolated urohzmatin in alcohol. 12. The alcoholic solution with caustic soda. 13. The alcoholic solution with zine chloride. 14. The artificially prepared urohematin in chloroform. 15. Action of peroxide of hydrogen on hzematoin. 16. The pigment produced by oxidation isolated ‘and reduced by sodium amalgam and filtered. 17. This filtrate treated with sulphuric acid. 18. Spectrum produced by the action of decolorised bile on hemoglobin. 19. The same or asimilar spectrum, got by acting on blood with alcohol and caustic soda. 20. Spectrum closely resembling sheep or ox bile, produced by the action of sodium amalgam for half-an-hour in the cold, on the body whose spectrum is shown in 19. (Compare 2 and 38, supra.) CuHart LY. Spectrum 1. Solar spectrum. 2. Sheep-bile. 3. Pigments of sheep-bile in chloroform. 4. Pigments of sheep-bile in alcohol. 5. Bands of hemochromogen, got by adding sulphide of ammonium to fluid giving 4. * And dissolved in alcohol. + This also represents solution of which sp. 15 is the map treated with caustic soda. 236 On the Colouring-matters of Human Urine. [Dec. 16, Spectrum 6. Thinner stratum of the same. » 7. Alcoholic extract of human bile pigments. “5 8. The same treated with sulphide of ammonium, showing the presence of hemochromogen. A 9. Alcoholic extract of human bile pigments with peroxide of hydrogen, violet stage. ,, 10. The same—end of reaction. ,, Ll. The absorption-band of serum, from blood of sheep (showing also O-hzmoglobin bands). ,, 12. Spectrum got by treating alcoholic extract of sheep-bile pigments with caustic soda for a short time. », 13. Spectrum closely resembling lutein got by longer action. This spectrum was also produced from hematin reduced by sodium amalgam, or at all events a spectrum very like it, by somewhat similar treatment. Table giving the wave-length corresponding to each division of the Scale reading. scale in millionths of a millimetre. Wave-length. ste mOSe Scale reading. Wave-length. 2 Ment eoa0) 1880.] On the Magnetic Inclination in the Azores. 237 Scale reading. Wave-length. Scale reading. Wave-length. Sy siesta ois A59 Qe aha, 4,42 OD ey RO AD57 OE Ba sec i AAO) 10) EM Ose 4.55 DO ee cope tye 438 OT a Sa aes 453 Ch eater Nea 437 Om Wyss yee ASL eh tava apie aie 435 Oe abs st Sha 450 CS chee, aaa 434 20) as a He 448 RO ORES ere ers 432 Oe chi okineawitts AA7 TON ES ose eel 430 OA ce a AAS LP SENN se em 429 OMe ds cu se 4.43 IOS Berne bate 427°9 IV. “Note on the Determination of Magnetic Inclination in the azores... by Iv W. THORPE, Ph.D. F.R.S. Received No- vember 13, 1880. With the exception of a series of determinations made by the officers of the ‘“‘ Challenger ” at Ponta Delgada, St. Michael, in 1873, no magnetic observations have, so far as I can learn, been made in the Azores since the time of Captain Vidal’s hydrographic survey in 1843-4. A visit to these islands during the past summer has enabled me to offer the smal! contribution to their magnetic history which forms the subject of the present communication. Magnetic observations are made with some difficulty in the Azores, on account of the intensely volcanic character of the islands. Con- siderable care was however taken in selecting the stations, and there is no reason to suppose that the observations are affected to any great extent by the nature of the soil or rock immediately beneath the instrument or in proximity to it. The places chosen were such as will enable subsequent observers to repeat the determinations on the same spots. The dip-circle employed was Dover 3, belonging to the Owens Colleve, Manchester: I had previously used this instrument in the course of my magnetic observations along the fortieth parallel in North America (‘‘ Proc. Roy. Soc.,” vol. 30, p. 1382), and am again indebted to Professor Balfour Stewart for the loan of it. It was pro- vided with two needles, each 34 inches long and 0°2¢ inch in maximum breadth. The same precautions were taken to preserve the needles from rust as are described in the communication above referred to, and the method of observation was identical with that previously adopted. In all cases duplicate and independent observations were made with the two needles. VOL. XXXiI. S 238 On the Magnetic Inclination in the Azores. [Dec. 16, The results are as follow :— 7 I. Island of St. Michael. In the garden of Senhor José do Canto, Santa Anna, Ponta, Delgada. Approximate position: lat. 37° 45' N., long. 25° 40’ W. The spot was that selected for the “ Challenger’ observations : Mr. do Canto has now marked it by a small (stone?) pillar. Loeal time. Needle 1. Needle 2. Mean. Aug. 28,1880. 12.0 to 3.30 p.m. 62° 40’0 62° 40°5 62° 40'2 N. The ‘‘ Challenger” observations in 1873 gave 63° 56'8 N.* If. Island of Terceira. At Angra: in the ground near the monument to Dom Pedro IV, 8 paces to the north of the Obelisk. Approximate position: lat- aa 39 N., long. 272 14’ W. Local time. Needle 1. Needle 2. Mean. Sept. 16,1880. llam.to12.12pm. 64° 10°5 64° 1071 64° 10°3 ITl. Island of Fayal. At Horta: 32 paces E.N.E. (magnetic) to the front of the Clock Tower to the north of the town. Approximate position: lat. 388° 32” N., long. 28° 38°30 W. Needle 1. . Needie 2. Mean. Sept. 1, 1880. 12.30 to 1.40 p.m. 63° 38°5 63° 38°5 63° 3875 Before leaving Lisbon for the Azores I made a set of observations: near Moita, at the Quinta do Hsteiro Furado, belonging to Mr. T. Creswell, which it may be desirable to include here. The station was identical with that on which I made the series of determinations of Photo-chemical Intensity, published in the ‘“ Philosophical ‘Trans- actions”’ for 1870. (‘‘ On the Relations between the Sun’s Altitude and the Chemical Intensity of Total Daylight in a Cloudless Sky,” Roscoe and Thorpe, “ Phil. Trans.,” 1870, p. 309.) The position was, approximately, lat. 38° 40’ N., long. 9° W. Hence it is prac- tically in the same parallel as the Azores. Needle 1. Needle 2. Mean. Aug. 3, 1880. 10.30 a.m. to 12.46 P.M. 59° :03°:0 59° 03:5 _ 592 0a72aNe * Communicated by Captain Evans, through Mr. Whipple. 1880. | On Heat Conduction in Highly Rarefied Air. 239 V. “On Heat Conduction in Highly Rarefied Air.” By WILLIAM CROOKES, F.R.S. Received November 18, 1880. The transfer of heat across air of different densities has been examined by various experimentalists, the general result being that heat conduction is almost independent of pressure. Winkelmann (“ Pogg. Ann.,” 1875-76) measured the velocity of cooling of a thermometer in a vessel filled with the gas to be examined. The difficulty of these experiments lies in the circumstance that the cooling is caused not only by the conduction of the gas which surrounds the cooling body, but that also the currents of the gas and, above all, radiation play an important part. Winkelmann eliminated the action of currents by altering the pressure of the gas between 760 and 1 millim. (with decreasing pressure the action of gas currents becomes less), and he obtained data for eliminating the action of radiation by varying the dimensions of the outer vessel. He found that, whereas a lowering of the pressure frem 760 to 91'4 millims. there was a change of only 1:4 per cent. in the value for the velocity of cooling, on further diminution of the pressure to 4°7 millims. there was a further decrease of 11 per cent., and this decrease continued when the pressure was further lowered to 1°92 millim. About the same time Kundt and Warburg (“ Pogg. Ann.,” 1874, 5) carried out similar experiments, increasing the exhaustion to much higher points, but without giving measurements of the pressure below ITmillim. They enclosed a thermometer inaglass bulb connected with a mercury pump, and heated it to a higher temperature than the highest point at which observations were to be taken; then left it to itself, and noted the time it took to fall through a certain number of degrees. They found that between 10 millims. and 1 millim. the time of cooling from 60° to 20° was independent of the pressure; on the contrary, at 150 millims. pressure the rate was one-and-a-half times as great as at 750 millims. Many precautions were taken to secure accuracy, but no measurements of higher exhaustions being given the results lack quantitative value. Jt appears, therefore, that a thermometer cools slower in a so-called vacuum than in air of atmospheric pressure. In dense air convection cenrrents have a considerable share in the action, but the law of cool- ing in vacua so high that we may neglect convection, has not to my knowledge been determined. Some years ago Professor Stokes suggested to me to examine this point, but finding that Kundt and Warburg were working in the same direction it was not thought worth going over the same ground, and the experiments were only 8 2 240 Mr. W. Crookes. [Decin: tried up to a certain point, and then set aside. The data which these experiments would have given are now required for the discussion of some results on the viscosity of gases, which I hope to lay before the Society in the course of a few weeks; I have therefore completed them so as to embody the results in the form of a short paper. An accurate thermometer with pretty open scale was enclosed in a 13 inch glass globe, the bulb of the thermometer being in the centre, and the stem being enclosed in the tube leading from the glass globe to the pump. Experiments were tried in two ways :— I. The glass globe (at the various exhaustions) was immersed in nearly boiling water, and when the temperature was stationary it was taken out, wiped dry, and allowed to cool in the air, the number of seconds occupied for each sink of 5° being noted. II. The globe was first brought to a uniform temperature in a vessel of water at 25°, and was then suddenly plunged into a large vessel of water at 65°. The bulk of hot water was such that the temperature remained sensibly the same during the continuance of each experiment. The number of seconds required for the ther- mometer to rise from 25° to 50° was registered as in the first case. It was found that the second form of experiment gave the most uniform results; the method by cooling being less accurate, owing to currents of air in the room, &c. The results are embodied in the following table :— (Rate of Heating from 25° to 50°.) Table I. Seconds occu- Total number Pressure. Temperature. pied in rising — of seconds each 5°. occupied. 760 millims. .. 25° oe 0 op 0 25 to 30 iF 15 a 15 30. 30 ao 18 of 33 35 ©6400 et, 22; Ms do 40 45 Me 27 52 82 45 50 of 39 Js yee 1 millim. 56 25° 5 0 so 0 25 to 30 BS 20 a 20 30 30 ae 23 Bs 43 35 «40 oe 25 a 68 AQ 45 aks 34: ; Simo? 45 50 an 48 Jey Sao 1880.] On Heat Conduction in Highly Rarefied Arr. Pressure. 620 M.* ai 59 M. 23 M. 12M. 5 M. Temperature. 25° 25 to 30 30. 380 30 = 40 AQ 40 45 90 25° 25 to 30 30 30 30 = 40 40 46 45 80 25° 25 to 30 30 «35 oo ©6400 40 45 45 50 25° 25 to 30 30 30 30 = «40 40 45 45 80 25° 25 to 30 30. 35 30 = «40 40 45 45 80 25° 25 to 30 30. 380 30 40 AQ 45 45 50 Seconds oceu- pied in rising each 5°. 71 116 * M = millionth of an atmosphere. of seconds occupied. 241 Total number “SWITTIW DIYLIWOWYHSFHI .S¢ OF SE .0 ' OGL eh pre ee ee Se aaa | Pi) ha esas Vea d 0 Al occupie WIT Total number of seconds in rising each 5°. d Seconds occu- pie SHLINOITTIW do =| | o De un ) Phosphate of sodium <0. soec)-)ee) ein ieee 195 Ae OLAX Js sc.< sie wl eicisteds susuets cena eee Oeneeome 75 IAS SHormic acid (96mimims) eo era 1-0 15. Cyanide of potassium (6 grs.) ........-.-. 78 16. Macrocosmic salt (120\e"s.) . co eu dee 25 lieu Natrate or PoOtassitM. 5) eles ob xaieeyelleladeeuehemarenene 14 oz. salt in 12 ozs. water.... ppd 1 OC coca ean0 yoo0 0% Strong solution 39 bP) 2) DOIMUAS EL) OZ. jte «yee rae Me nee A Oh 06 .4.2.00,5 0 Moder, ately strong solution. . sacs SOlUtION\..; (es sneer coe ere ee ee ee ee eoceceee ee eeee ec 4 oz. in 14 Ones water. F 5 grs. in 100 c.c. water . Bees 6 Rather weak solution ........ bb) eeeee¢eer#8¢?e iL om in 8 Oe Water ticsc eee aqueous ammonia (L Soudnacn'lige cll Rabe ee [Dec. 16, The electric current was in all cases sent from Direction of flow of liquid. PUPA U TELL bedded 1880. } Experiments on Electric Osmose. 255 Direction No. Substance. Strength of Solution. of flow of liquid 53 | Sulphocyanide of ammonium..| Strong solution ............ —>?* 54 | Tungstate of potassium ......| Saturated solution .......... = 55 | Phosphorous acid .......... SHARC MVR ONION. 6 oo Coon 6600 oC — 25. || AUASGIVBIIE ONE GOCURIN G6 tL oloe be Bil Soo duodbobcos booeouGode code — 57 | Potassic fluoride (pure) ...... == oon) Miguor arsenicalis..........- British. Pharmacopoeia strength — 59 | Hypophosphorusacid........| Saturated solution ...... =: 60 | Sulphocyanide of potassium ..| Strong solution ............. —>?* 61 | Ferridcyanide of potassium....| Moderately strong solution ... = 62 | Sodic hydrate...............| Strong aqueous solution ...... => 63 | Potassic cyanide............. Saturated solution........... No per- ceptible flow. GA> 5 | Sodie carbonate << .. .c006 +s m, sain tat aiee ere aad — 65 | Potassic carbonate .......... A Tie bakevonclatte bee at oneis — 66 | Sodic hydrate ..............| 200 grs. in 1 oz. absolute NEOIIC so9c46 ob 00et so G4 ae = +67 | Hypophosphite of sodium . Strong alcoholic solution...... — +68 | Baric bromide ..............| Nearly saturated alcoholic solu- (HOM coi goo okered co ou eons = \ In all the foregoing experiments (sixty-eight in number), in which an electric current passed from one portion of liquid through a clay diaphragm to another portion, osmose occurred, except in No. 63. In these experiments, fifty-five substances, different in kind, were employed, including about twenty-seven neutral salts of the most varied composition, about ten alkaline ones, twelve acids, two alkalies, and one acid salt; twelve of the substances of different degrees of dilution were also examined. As with solutions of potassic cyanide, yellow potassic chromate, acid chromate of potassium, or sodic carbonate (liquids which show an apparent opposite movement in the research referred to), the osmose was in the same direction as the electric current, and showed no sign of reversal of movement, I conclude that the apparent movement of the lower liquid in that research is probably of a different character from “ electric osmose.”’ ' From these experiments, it also appears that the direction of electric osmose is in nearly all cases the same as that of the current; that rapid electric osmose is not confined to dilute solutions; and that in some cases too concentrated a solution prevented the effect (compare Nos. 17-20, 54, also 4, 5, and 63). From the circumstance that the direction of osmose was the same in * In consequence of the large quantity of orange-red solid matter liberated, the direction of the osmose could not be determined. + In these three experiments a current from a single series of 25 Grove’s cells was employed. y 2 256 Experiments on Electric Osmose. [Dee, 16, the most diverse solutions, viz., in acids, alkalies, neutral salts, aqueous and alcoholic liquids, concentrated and dilute solutions, &c., we might be apt to infer that the chemical composition of the electrolyte had no influence upon it; but as a single exceptional instance will overturn the widest generalisation, so the exceptional behaviour of a solution of bromide of barium in absolute alcohol invalidates the conclusion that the direction of flow of liquids in electric osmose, is independent of the chemical composition and molecular structure of the liquid. The danger of drawing conclusions from too limited a number of instances is well illustrated in this case, especially when we further remember that it is the exceptional instances which usually disclose the widest truths. As the exceptions formed a very small proportion of the whole number of examples, it would appear that the direction of the flow depended very much more frequently upon the direction of the electric current than upon the internal architecture of the liquid. In order to be able to compare the direction of motion of the mass of the liquids, produced by passing an electric current from a heavier to a lighter liquid lying upon it without a separating diaphragm, in the research already referred to, with that produced when the liquids were separated by a vertical diaphragm, additional experiments were made. The osmose cells employed in these experiments were about A:7 centims. high, 2°5 centims. long, and about 2°0 centims. wide at right angles to the diaphragm; and the diaphragms were cemented in with sealing-wax. Experiment 1.—Current from 26 Grove’s cells in single series, passed from a saturated solution of sodic sulphate to a one-fourth saturated one of potassic chloride. Osmose occurred in the direction of the current. Experiment 2.—Current passed from a mixture of 1 volume of sul- phuric acid and 7 of water to one composed of 5 volumes of a satu- rated solution of oxalic acid, and 3 of water. Osmose produced in the usual direction. Experiment 3.—Current passed from a strong solution of potassic chloride to a mixture of 1 volume of a saturated one of ammonic sulphate and 3 volumes of water. Rapid osmose took place in the ordinary direction. Experiment 4.—Current from 5 Grove’s cells in single series, passed from a solution composed of 1 volume of a concentrated solution of sodic hydrate and 3 volumes of water, to a saturated one of sodic car- bonate. Osmose occurred in the usual direction. Experiment 5.—The same current, passed from a strong solution of ammonic nitrate to one of 1 volume of a saturated solution of sodic carbonate and 3 volumes of water. Feeble osmose in the ordinary direction took place. 1880. } Presents. 257 From the results of these experiments, and of those referred to, it appears that the presence of the diaphragm considerably affects the directions of the movements. By means of numerous experiments subsequently made, it was also found that electric osmose usually proceeds more rapidly from a weak to a strong solution of a given substance than in the reverse direction. The Society adjourned over the Christmas Recess to Thursday, January 6th, 1581. Observations and Reports. Batavia :—Maenetical and Meteorological Observatory. Observa- tions. Vol. IV. 4to. Batavia 1879. The Observatory. Calcutta :—Geological Survey of India. Memoirs (Paleontologica indica).-- Ser’ X. Vol. 1.» Parts 4, $.\.Ser. X¥IUL. “Part 2. Ato. Calcutta 1880. Memoirs. Vol. XV. Part2: Vol. XVII. Part 2. 8vo. Calcutta 1880. Records. Vol. XIII, Part 3. 8vo. The Survey. _ Cambridge (U.S.) :—Observatory of Harvard College. Annals, Vol. XII. Catalogue of 618 Stars. 4to. Cambridge 1880. The Observatory. Helsingfors:—Societé des Sciences de Finlande. Observations Météorologiques. Année 1878. 8vo. Helsingfors 1880. The Society. Presents, December 9, 1880. Transactions. Berlin :—K. Akademie der Wissenschaften. Abhandlungen, 1879. ‘Ato. Berlin 1880. Monatsbericht. Marz bis Aug. 1880. Svo. Berlin 1880. The Academy. Berwick :—Berwickshire Naturalists’ Club. Proceedings. Vol. IX. No. 1. 8vo. The Club. Béziers :—-Société d’Etude des Sciences Naiurelles. Compte-Rendu des Séances. 1876-78. 8vo. Béziers 1877-79. The Society. London :—Clinical Society. Transactions. Vol. XIII. 8vo. London 1880. The Society. Institution of Civil Engineers. Minutes of Proceedings. Vol. LXII. 8vo. London 1830. The Institution. Royal Geographical Society. Journal. Vol. XLIX. 8vo. Loudon. The Society. Royal Medical and Chirurgical Society. Transactions. Vol. LXITI. 8vo. London 1880. The Society. 258 Presents. , (Decri6; Journals. Horological Journal. July to December, 1880. 8vo. London. The Editor. Journal of Science. May to December, 1880. 8vo. London. The Editor. Mittheilungen aus der Zoologischen Station zu Neapel. Bd. II. Heft 1. 8vo. Leipzig 1880. ) The Editor. Nature. Vol. XXII. 4to. London 1880. The Editor. Nautical Almanack, 1884. 8vo. London 1880. The Admiralty. Niederlandisches Archiv ftir Zoologie. Bd. V. Heft 2. 8vo. Leiden 1880. | The Editor. Observatory. July to December, 1880. 8vo. London. The Hditor. Scientific Roll. Part 1. No.1. 8vo. London 1880. The Editor. Scottish Naturalist. Nos. 39, 49. 8vo. Hdinburgh 1880. The Editor. Van Nostrand’s Engineering Magazine. Vol. XXIII. 8vo. New York 1880. The Hditor. Barbera (Luigi) Introduzione allo Studio del Calculo. 8vo. Bologna 1881. The Author. Davidson (Thos.), F.R.S. Liste des principaux Ouvrages, Mémoires, ou Notices, qui traitent directement ou indirectement des Brachiopodes vivants et fossiles. Svo. Bruwelles 1880. The Author. Duncan (P. Martin), F.R.S. Cassell’s Natural History. Vol. IV. Ato. London. The Publishers. Frederick the Great. Politische Correspondenz. Band 4. 4to Berlin 1880. The Berlin Academy. Hill (Sir Rowland), F.R.S., and G. Birkbeck Hill. The Life of Sir Rowland Hill and the History of Penny Postage. Two vols. 8vo. London 1880. Lady Hill. Moore (F.) The Lepidoptera of Ceylon. Part 1. 4to. London 1880, The Government of Ceylon. Siemens (C. William), F.R.S. Copy of Communications from the “Times” and from “ Nature,” regarding the Smoke Question. 8vo. London 1880. The Author. Presents, December 16, 1880. Transactions. Bombay :—Geographical Society. Transactions. Vols. VI and XVII. 8vo. Bombay 1865. The Society. 1880.] Presents. 259 Transactions (continued). Royal Asiatic Society. Journal of the Bombay Branch. Vol. XIV. No. 87. 8vo. Bombay 1880. The Society. Gloucester :—Cotteswold Naturalists’ Field Club. Proceedings. 1865-78. 8vo. Gloucester. The Club. London :—Anthropological Institute. Journal. Vol. IX, No. 4 Vol. X, No. 1. 8vo. London 1880. The Institute. British Museum. Catalogue of Oriental Coins. Vol. V. 8vo. London 1880. The Trustees. Chemical Society. Journal. Nos. 211—217. 8vo. London 1880. The Society. Hast India Association. Journal. Vol. XIII. No. 1. 8vo. London 1880. The Association. Entomological Society. Transactions. 1880. Parts 2 and 3. The Society. Geological Society. Quarterly Journal. Vol. XXXVI. Parts 3 and 4. List, 1880. Abstracts of the Proceedings. Nos. 390-1. 8vo. London 1880. The Society. Linnean Society. Transactions. Botany. 2nd Series. Vol. I. Part 9. 4to. Journal. Botany. Nos. 106-8. Zoology. Nos. 82--4. 8vo. London 1880. The Society. Mathematical Society. Proceedings. Nos. 161-2. 8vo. The Society Meteorological Society. Quarterly Journal. Vol. VI. Nos. 35, 36. Svo. London 1880. The Society. Musical Association. Proceedings. 1879-80. 8vo. London 1880. The Association. National Association for the Promotion of Social Science Sessional Proceedings. Vol. XIII. Nos. 5, 6. 8vo. London 1880. The Association. Observations and Reports. Brussels :—Commission de la Carte Géologique de la Belgique. Levé Géologique des Planchettes Aerschot, Anvers, Beveren, Boisschot, Boom, Heyst-op-den-Berg, Lierre, Malines et Putte. 8vo. Bruzelles 1880. With Maps. The Commission. Naples:—Zoologische Station zu Neapel. Fauna und Flora des Golfes von Neapel und der angrenzenden Meeres-abschnitte. Monographie I. 4to. Leipzig 1880. Dr. Siemens, F.R.S. Paris:—Dépot de la Marine. Annuaire des Marées des Cotes de France, 1881. Annuaire des Marées de la Basse Cochinchine, 1881. 12mo. Paris 1880. Annales Hydrographiques, 1879, 2e Semestre; 1880, ler Semestre. 8vo. Paris 1879-80. Index Alphabétique de noms de Lieux, Tomes XXIX 4 XLI. 8vo. 260 Dr. G. W. Royston-Pigott. Observations, &c. (continued). | Paris 1879. Supplément au Catalogue. 8vo. Paris 1880. Pilote de la Manche: Cotes nord de France, Tome I. 8vo. Paris 1880. And thirty Charts and Plans. Rangoon :—Report on the Irrawady River. By R. Gordon. Four Parts. folio. Rangoon 1879-80. The Author. Righi (Augusto) Contribuzioni alla Teoria della Magnetizzazione dell’ Acciaio. 4to. Bologna 1880. The Author. Savery (Tho.) Navigation Improv’d: Or, the Art of Rowing Ships of all Rates, in Calms, With a more easy, swift, and steady Motion than Oars can. 4to. London 1698. [ Reprint. | Mr. R. B. Prosser. Wartmann (Auguste-Henry) Recherches sur ]’Enchondrone, son Histologie et sa Genése. 8vo. Genéve et Bale 1880. The Anthor. Williamson (Benjamin), F.R.S. An Elementary Treatise on the Integral Calculus. S8vo. London 1880. The Author. Zollner (Johann C. F.) Transcendental Physics. Translated by C. C. Massey. 8vo. London 1880. Mr. W. H. Harrison. “Microscopical Researches in High Power Definition.” By G. W. Royston-PicotT, M.A., M.D. Cantab., F.R.S. Re- ceived May 23, 1879. Read June 19. [The portion between square brackets recerved November 20.] Part I. [ PLATES 3 and 4. ] In the present communication it is intended to advert to the subjects— (1.) Minimum visibility. (2.) The effects of excessive angular aperture in obliterating minute molecular structure. . (S.) Minute measurement and a micrometer gauge. (1.) Minimum Visibility. Spider-lines miniatured down to the fourteenth part of the hundred- thousandth of an inch have been made distinctly visible to ordinary good eyesight under proper microscopical manipulation. The question then arose whether an actual thing so small as the millionth of an inch could be descried in the microscopic field of view. According to recent researches, 1t would appear from formule derived from the undulatory theory of light, that brilliant disks are developed from points of light which vary inversely in diameter with the increase Microscopical Researches in High Power Definition. 261 of angular aperture of the objective employed, and directly as the wave-length of the kind of light employed.* Professor Helmholtz and Professor Abbé have independently arrived at this beautiful law. And Professor Helmholtz cautiously states, how- ever, there may be some conditions which may modify this law. It follows from this principle that thin brilliant lines of light can be best separated by glasses of the highest angular aperture; and the separating power can be measured by the sine of the semi-aperture. Now for wave-length =53,55f we may thus tabulate them (when $\= 50000 100,000) :— The Values of ¢ for Different Apertures. Aperture. (e,) the limit of proximity - of bright lines or disks. “oll Ga Ree ie eee . 100,000th of an inch. LAD oie a ee eee 98,480th Ss 140) a eee 93,970th = £30) 5 supe calaelltea iets 76,600th _,, WD SSeS A ae ne 50,000th es BA Socialis aie, sisucus a's,0 6 4/s\e/e « 34,200th of 7A) DSS ER ec ae Sea ee 17,300th = LE (ULL ges anaes 13,000th —s, 1D oo6 igh eee eee SUN Ree SION WR Che eve ov ob entasnks) 6% 4,360th se i. see 870th _—s, eae we iste ge ay ai 436th _,, Such values as these have accordingly been generally accepted as limits to the resolvability of close lines with objectives of given aper- tures. Further, it is said that lines drawn at the rate of a hundred thousand to the inch represent the limit of microscopic visibility. In a paper on this subject by the author it has been shown that a bright space enclosed between two spider-lines, miniatured so as to form a bright interval 555455, was distinctly visible, whilst the webs actually were about the ~455 and 795 of an inch in thickness.t Under these circumstances, it was interesting to determine whether — us = 2.sin « X\=wave-length ; a=semi-angular aperture ; « the distance between the centres of the disks in contact. + Sir John Herschel estimates the wave-lengths as follows, in parts of an inch— Noveisiarsis Greeny. ake cree ce ecient Doone Neves Nbermegiabe ..s. 2 1,000 HP MOOOOOOtH. ....+......- 204 Heme OOO: ..2 560s v0 ss Al Mer rAUOQOOGH. CL eee ees 514 1- 200} U0 Un eer 69 | eMEZ00. O00. s4's's <0: 103 BE TOOOOOEIS s.ccosvae apctein a 206 HES OO0Gh«. 2... +. »s.: 4124 PPOMUOUOLINSs st ce. cc ks ce 41 2,000 FEOOOOO0CH Ue es ee Ss 60 2,500 tT See “ Circular Solar Spectra,” by the writer, “ Proc. Roy. Soc.,” vol. 21, p- 426 266 Dr Gi. SW. Royston-Pigott. research is beset with many difficulties and variable factors, some of which may easily be overlooked or even unsuspected. As nearly all organic tissues teem more or less with minute mole- cules, their variable behaviour and optical appearances have received close attention for many years, and I have concluded that— A.—A refracting molecule changes its appearance and phenomena according to the nature of the fluid by which it is surrounded, also with the fluid in which the objective may be immersed.* B.—It changes also, in an extraordinary manner, according to the angular aperture of the objective employed, according to the refrac- tions of the media, and the direction of illumination and the paral- lelism or degree of convergence or divergence of the illuminating pencil transmitted. C.—Other interesting factors are the residuary aberrations of the compounding lenses of observation and the greater or less intensity of diffraction phenomena introduced by the mode of illumination. In a short paper, it will be convenient partly to deal with these questions as they arise in the experiments rather than seriatim. (2.) Hucessive Angular Aperture considered. The principal and chief, I may say the most valuable, feature in the appearance of a refracting molecule is the extraordinary variability of the blackness and thickness of the marginal annulus. This thickness and consequent visibility is dependent on the value of the refraction into the given media, and the angular aperture of microscopic observation: partially also upon the situation of the focal point of the lenticular illumination. Hzample 1.—A glass spherule (01 diameter) is examined with a pocket lens. An intensely black broad ring is seen against the lght. The same black ring is visible in bubbles frequenting plate glass in windows. The angular aperture of the pupil of the eye is about a degree for an image seen at 10 inches distance. Melted glass fila- ments are also instructive (see figures a, B, y, 6, ¢, €, 9, 9). * It is not many years since lines on diatoms were all that were searched for. But as these are formed by an aggregation of siliceous spherules, they present extra- ordinary opportunities for investigating optical characters which must necessarily belong to them—of a degree of minuteness of a highly satisfactory order—such as black annuli, focal points varying with chromatic refraction, shadows varying in contour according to the extinction of transmitted rays by obliquity of illumination : appearances changing with the refractive index of the media in which they are immersed. Only the very finest glasses extant can display the black margin of a diatomic spherule the ;5355 of an inch in diameter; and very few, if any, can be obtained capable of displaying focal points and the natural coloured foci at different chromatic foci. . . | | Microscopical Researches in High Power Definition. 267 Example 2.—A microscope with ten degrees aperture considerably diminishes the relative thickness of the black annulus. Hzample 3.—With forty degrees it is much attenuated and it vanishes altogether when the angular aperture reaches a certain rela- tion to the lenticular refraction. The vanishing limits vary with the nature of the refracting spherule, and also with the angular observing aperture and the direction of the axis of illumination.* If it be formed of plate glass whose index of refraction into air is 1500, the vanishing angular aperture is 83° 36’. Bui as the index is higher, this angle increases with heavy flint glass (m=1'988) to 164° 6". In both these cases the black defining annulus of the spherule is in these limits attenuated almost to evanescence. Glasses, therefore, of small angular aperture develope the broadest black outlines in a minute refracting molecule. The change of appearance of translucent bodies composed of masses of refracting molecules is very finely shown in observing a variety of scales forming the dust of moths and butterflies. Hzample 4.—Featherlets of the death’s head moth. Low angular aperture, 10°. The whole animal bristles with black feathers, armed with three or four long black spines: all of a dark but rich umber colour, tipped intensely black; each spine shows an exceedingly thin line of light running centrally up between two broad intensely black margins. (Hxactly what is seen when examining a thread of spun glass with low aperture.) (Tig. 1, Plate 3.) Increasing Aperture.—Colours pale. Light flashes through. The spherules begin to appear edged with black annuli, which gradually attenuate with higher angled glasses. (Direct light.) (Wig. 2.) (Fig. «, ¢.) It is remarkable how the colour changes as the aperture increases, through paler shades, until a general sparkling radiance appears to steal through the mass of molecules formerly darkling with the uni- versal presence of black annuli due to low aperture. The black edgings also of terminating membranes extending from spikelet to spikelet, and those of refracting tubules become indistinct. The obliteration of marginal shadows is well shown by first using low and then large aperture on another very beautiful object, viz. :— Hzample 5.—Plumelets of the Hipparchus Janira. Aperture 20°. Power 200. The filaments of the plume and their clubbed ends are all intensely black (Plate 4, fig. 13a). * “The use of a new Aberrameter, for testing Aberration and the Effect o1 Aperture,” “ Quart. Jour. Mic. Science,” January, 1871. The angles subtended by the black shadow are there calculated and tabulated. 268 Dir iG. We Royston-Pigott. Aperture 44°.—All still intensely sharp and black with the fine definition of a Wray “ half-inch.” Aperture 55°.—Wray glass. Margins thinner; the filaments begin to be translucent and at the spherically clubbed ends a focal point of light appears. | Aperture 94°.—A remarkably fine 1-6th by Béneché of Berlin. Power 600. Increase of translucency at every part; black margins attenuated. Club margin much thinner (fig. 130). Aperture 140°.—Fine 1-8th. Power 800. Black margins almost attenuated to invisibility; clubs translucent altogether ; no annulus. It is interesting to state that the thickness of the filaments of this plume vary between goigg and sohos, yet these are beautifully distinct (aperture 12° and 50 diameters 2-inch objective), and yet under this amplitude a single filament subtends* less than 20 seconds of arc. The exceedingly black and sharp appearance of these filaments doubtless accounts for their actual visibility under this very small visual angle. Now this exactly represents a line 1-1,600,000th thick (considerably less than a millionth of an inch) seen under a power of 1,000 diameters. If then the minute fibrille of the plume can be clearly distinguished as closely packed black lines, at a visual angle of twenty seconds, with low aperture of twelve degrees, this result is fatally opposed to the popular idea that very close lines, or very minute lines or bodies, can only be distinguished with large angular aperture. These lines - were most sharply seen, though less than 1-80,000th thick (fig. 13a, Plate 4). — But besides the black sharply defined ring or annulus always de-. veloped in a refracting molecule by using low aperture, oblique illu- mination produces a thorough change in this black ring: it is trans- formed into various black crescents; and a row of such molecules approximately appears as a continuous black line sometimes notched. A tubule also produces a variety of marginal shadows according to the angular aperture of observation and according to the arrangement of internal molecules, and their combined shadows produce a variety of effects of an important character (fig. 6). It follows from these considerations that researches upon inex- — hausted structures (those inadequately resolved for instance), must be conducted with especial reference to the development and detection of shadow annuli or bands, or notched black lines, and with special % ga are x power _ TODD eee Slee 2 Aa” rad. 10 inches 16000 an (3s er Ch x power =a Olen x 1000 ee rad. 10 16000 Microscopical Researches in High Power Definition. 269 regard to the angular aperture of the most effective kind, whether modified by the limitation of illuminating rays or by reduction of aperture; or by the refractive media concerned, viz., immersion fluids and “mountings.” (Fig. 10). Very striking examples of the disappearance of distinctive shadows, and consequent obliteration of structural molecules, are afforded by the coarser Podura scales; principally due to the use of excessive angular aperture (figs. 3, 5). It is now eighteen years since a single observation suggested the present research, which has been followed up almost continuously towards the attainment of transcendent high power definition. Dark molecules suddenly started into view under accidental mani- pulation, but were most difficult of reproduction, and in finer objects of the same kind were often utterly unattainable. The questions naturally arose—are certain optical zones in the objectives more effective ; the spherical aberrations existing there as a minimum; or are there other occult causes of occasional yet splendid definition under high powers? This did not appear at all to be a question of the miununum visible because the objects exceeded the 1-50,000th of an inch in diameter. These points may be illustrated by the records of some observa- tions made by the writer. Although the molecules of the scale from the insect Podura domestica are large, the 1-45,000th, a stringlet of these bafiles the powers of the finest glasses now extant, as ordinarily employed, whilst those of the finer test scales (the Podwra curvicollis) are hopelessly attempted by every observer who trusts to excessive angular aper- ture (Pod. domestica, fig. 3, Plate 3).* Hzample 6.—Data for Resolution. 2-3rd objective as condenser : a U-shaped stop aperture placed on its front lens.+ Powell and Lealand’s 1-50th objective. Direct light of petroleum lamp. ftesult.—A grand display of long rows of whitish molecules in con- tinuous contact (power 2,500), fig. 4, and between these rows are seen closely packed rouleaux of a dark lead-blue colour in a parallel higher plane. The molecules appear like a pearl necklace, in stringlets of twenties and thirties, which can be easily counted, as each molecule appears to be about three degrees of visual angle in diameter. Remove the U-shaped stop, and the whole beautiful resolution dis- appears (fig. 5, left half). If, now, instead of using this difficult * See Plates 73, 74. ‘Monograph of the Collembola and Thysanura,” by Sir John Lubbock, Bart. (Ray Society). 7 This method causes a slight obliquity of illumination, besides considerably reducing the angular aperture of the objective. Aperture of condenser 30°. TL O=s54554 10 x 2500 = 3, =3° nearly. VOL. XXXI. U 270 Dr. G. W. Royston-Pigott. glass, a very fine 1-8th is used, at the same time that very oblique light illuminates the object, by tilting the axis of the condenser, black crescentic annuli are clearly developed (fig. 6). There is no doubt the view manipulated is entirely due to shadow thus developed and the preservation of marginal darkness. In this way the object may be shown with a very fine half-inch objective. The molecules are indeed huge compared with other visibilities: perhaps the explanation here given may enable other observers to confirm their existence in this comparatively easy object. The magnificent Oil Immersion Lens, by Zeiss, of Jena, utterly fails with its full aperture to show the appearances just described. It displays grandly indeed the long corrugations, tubules, or ribs cross- ing each other irregularly, but entirely misses their beautiful contents: fully charged though they be with spherules (see fig. 7, Plate 3). The total disappearance of this interesting structure, on the field of such a glass, is both surprising and instructive to the beholder. Experiment 7.—Data of Resolution. Inferior 1-8th P. and L. 140° Objective, 1862. Aplanatic condenser 44° of aperture (Wray half- inch). February 5th, 1879. Power 800: cloudy daylight. Direct light. The ribs are interrupted and alternately mottled blue and rose colour, slightly pink-coloured molecules without shadow annuli just discoverable peeping between the interrupted ribs. (The lowest focal plane must here be diligently searched. ) Hzample 8.—Data. Objective by Powell and Lealand of exceed- ingly fine quality. (Screw collar has 23 turns and was opened to 25° from zero.) Cloudy daylight; Same illumination. Result.—Hidolic black dots very much smaller than spherules dis- cernible between very decisive appearance of spines or exclamation markings (!!!). Atavery high plane of focal vision, spines alone, the familiar optical test (fig. 8). This singular result requires investi- gation. Hidolic black dots are generally discoverable on a focal plane above the centre of refracting molecules. EHzample 9.—Newest form of P. and L. 1-10th immersion, a glass of remarkable precision. Lowest attainable focal plane, with “collar” fully open, so that ‘“‘nose”’ is in contact with the ‘‘cover.” Daylight as before. Aper- ture of direct illuminating cone 44°, formed by Wray half-inch. Result—The spines are broken into double rows of minute black dots. Shadowy white beads are glimpsed (with most scrupulous” attention to focal and collar adjustments) between the spines. But when the condenser is tilted, strong dark crescentic annuli suddenly appear on the shadowy whitish molecules. Hzample 10.—Data. 3p.m. Sun dimly visible: Povell and Lea- land’s diaphragm No. 2, diameter 0°2 to reduce angular aperture of Microscopical Researches in High Power Definition. 271 Zeiss oil lens used as condenser. Objective Wray 1-10th immersion of extraordinary precision of definition; same object as before. Rtesult—Whenever the sunshine was dimmed with clouds both spaces between the spines and the spines themselves are thoroughly resolved into molecules at the same instant. (A very difficult operation.) ) circular and much less refractive—a and b are acted upon differently by staining solutions. The highly refractive bodies form the nodal points (2) of a delicate reticulum which encloses the circular less highly refractive cells. Traces of this fine reticulum can be seen in the medullary portion. The granular cells mentioned in a preceding note (‘‘ Proc. Roy. Soc.,” vol. 27, p. 369) take their origin in the connective tissue cells which constitute the network of the medullary portion. These granular cells not only help to form the concentric corpuscles, but are actively concerned in the formation of fibrous tissue; their fibrillated pro- cesses are sometimes found to be attached to newly formed connective tissue. The granular cells are identical with some forms of giant cells— they are not the plasma cells of Waldeyer, although plasma cells are present in the thymus, as has been described by Hhrlich. January 27, 1881. THE PRESIDENT in the Chair. The Presents received were laid on the table and thanks ordered for them. The following Papers were read :— I. “The Refraction Equivalents of Carbon, Hydrogen, Oxygen, and Nitrogen in Organic Compounds.” By J. H. Guapb- STONE, Ph.D., F.R.S. Received January 4, 1881. Since the communication which I had the honour to read before this Society in 1869, ‘“‘On the Refraction Equivalents of the Ele- ments,’ very little has been done on the subject. My own contribu- tions have been almost confined to two communications in the “¢ Journal of the Chemical Society,” in 1870; the one a lecture on the subject in general, the other a paper on the “ Refraction Hquiva- VOL. XXXI. 208 328 =r. J. H. Gladstone. Refraction Equivalents of [Jan. 27, lents of the Aromatic Hydrocarbons and their Derivatives ;” together with a discourse at the Royal Institution in March, 1877, on “The Influence of Chemical Constitution on the Refraction of Light.” In the meantime, observations on many substances have gradually accu- mulated in my note-book. Of late, however, the importance of the subject in regard to theories of chemical structure has been recognised by Dr. Thorpe and other chemists in this country, and attention has been recalled to it in Germany by the papers of Briihl, who, following closely in the footsteps of Landolt, has endeavoured to explain the results in the language of modern organic chemistry. At this juncture it may be of service to put on record my present views in regard to the refraction equivalents of the four principal constituents of organic bodies—carbon, hydrogen, oxygen, and ni- trogen. The figures in this paper are always reckoned for the line A of the solar spectrum, the refraction equivalent being the specific refraction for A multiplied into the atomic weight, or = In the present stage of the inquiry, though the results are deduced from many observations, I have not thought it desirable to go beyond the first place of decimals. Carbon.—Carbon in its compounds has at least three equivalents of refraction, 50, 6°0 or 6:1, and about 8°8. Whether its refraction should be one or other of these appears to depend on the way in which the atoms are combined. E When a single carbon atom has each of its four units of atomicity satisfied by some other element, it has a value not exceeding 5:0. There are some indications that the value may be slightly less than this. When a carbon atom has one of its units of atomicity satisfied by another carbon atom and the remainder by some other element, it has the value of 5:0, the same as in diamond. This is also the case if two of its units of atomicity are satisfied by carbon atoms. The majority of organic compounds of course fall into this category. When a carbon atom has three of its units of atomicity satisfied by other carbon atoms, its value is 6°0. The most striking instance is that of benzol, C,H, (refraction equivalent 43:7), in which it is diffi- cult to conceive that each carbon atom is not in the condition just de- scribed, and which, reckoning 1°3 for each hydrogen, gives a little less than 6:0 for each carbon. Styrol, CgH, (57°8), gives a similar value. There are other organic compounds in which only some of the atoms of carbon have the higher value. It has been especially the work of Brihl to point this out, and to show that where they occur (as in amylene or the allyl compounds) the carbon atom is in a con- dition similar to those in the phenyl nucleus, that condition in fact 1881.] Carbon, Hydrogen, &c., in Organic Compounds. 329 which is generally represented in our graphic formule by two carbon atoms linked by double bonds. The value assigned by Briihl in such cases is, however, 6:1. This somewhat higher figure is deduced from the aggregate value of the six carbon atoms in the nucleus of the aromatic series, which (except in benzol and its simpler substitution products) would appear to be nearer 3/7 than 36. If equally distributed over the six atoms this would give a value of at least 6-1 for each. The fact, however, is susceptible of another interpretation. It does not follow that in these more complicated bodies all the carbon atoms are exerting the same influence on the rays of hight. The replacement of hydrogen by some monad radicle is an important change; and if that radicle be CH; it is evident that according to present views the carbon atom must have all four of its units of atomicity satisfied with carbon, and by analogy we should expect it to have its refraction increased. What that in- creased value may be, or which indeed of the two hypotheses is most in accordance with the facts, it seems to me that we have not yet sufficiently accurate data for determining. When a carbon atom has all four of its units of atomicity satisfied by other carbon atoms, each of which has the higher value of 6:0 or 61, its equivalent of refraction is greatly raised. There are com- pounds in which the atoms of carbon actually outnumber the atoms of hydrogen or its substitute, such as naphthalene, C,,H, (ref. eq. 751), naphthol, C,)H,O (79:5), phenanthrene, C,,H,, (108°3), and pyrene, C,H), (126°1). That the refraction is greatly raised is evident from the fact that, if we were to reckon all the carbon atoms at 61, the refraction equivalent of the body would not be fully accounted for. It is evident that in pyrene only ten of the atoms of carbon can be in the same condition as they are in benzol or styrol, the other six must have all their units of atomicity satisfied by carbon alone. Now, if we allow 6°0 as the value of each of the ten carbons, and 1°3 for each of the ten hydrogens, we get 73:0, which taken from 126°1 leaves 53:1 for the remaining six atoms of carbon, or 8°8 for each. By a similar calcula- tion the four extra atoms in phenanthrene are found to have the value of 88 each. Taking oxygen at 2°9, naphthol gives 9:1 for each. But the experimental data do not indicate a higher value than 8°4 for each of the extra carbon atoms in naphthalene. Provisionally I venture to assign 8°8 as the refraction equivalent of this highest carbon. There are several other bodies, such as anthracene, anethol, furfurol, and hydride of cinnamyl, which from their abnormally high refraction appear to contain carbon in this last condition. Hydrogen.—The general evidence with regard to hydrogen in organic compounds tends to show that it has only one refraction equi- valent, that originally assigned to it by Landolt, 1:3. Oxygen.—Brihl has been the first to point out that oxygen in organic 282 330 Mr. W. H. L. Russell on [Jan. 27,. compounds has two values, and he comes to the conclusion that it has the value 3°35 where the oxygen is attached to a carbon atom by a ‘double linking, but 2°76 in hydroxyl and where the oxygen is united to two other atoms.* This is deduced from experimental data: but there are other results which present difficulties. Thus the refraction of no substance is more certainly known than those of water, wood spirit, and alcohol. But the oxygen in H,O (5:9) appears to have the higher number 3°3, notwithstanding its union to two atoms of hydrogen, while in CH,O (13:1), C,H,O (20°8), as well as higher alcohols, and the diatomic ethene alcohol, C,H,O, (23:7), and the triatomic glycerol, C,;H,O, (83°9), the oxygen is not 2°76, but 2:9 or 3:0, the numbers. originally assigned to this element. - Nitrogen.—Nitrogen has two values, 4°1 and 5:1, or thereabouts. The lower value, 41, is that originally deduced from cyanogen and. metallic cyanides, and it seems to be generally confirmed by the observations on organic cyanides and nitriles. The higher value, 5:1, is deduced from all my observations on organic bases and amides, such as diethylamine (39°4), triethylamine (54°6), formamide (17-4), &c. The determination of the value of nitrogen in nitro-substitution products presents some peculiar difficulties. The observations are not accordant. ven were the value of NO, obtained with certainty, it would not be easy to say how much should be attributed to the oxygen, especially when it is remembered that combination with oxygen alters very materially the refraction of the analogous elements, phosphorus and arsenic. ' I hope shortly to submit to the public the data for these calculations, and in fact the whole of my recent observations on the refraction of organic compounds, together with a fuller discussion of the conclusions. that may be drawn from them. II. “On certain Definite Integrals.” No. 8. By W. H. L.. RUSSELL, F'.R.S. Received January 6, 1881. I commence this paper with some general reflections on the theory of definite integrals. A definite integral may be written thus— idefa by 6. 222) == O(a, coven: If we expand in terms of (a) and equate the coefficients of a” we shall have [faeAc, OS 6... 2) =O, (H; 0 .eee * These have been calculated for line A. 1881.] certain Definite Integrals. 331 And again expanding in terms of 6, and equating coefficients of 6”, we shall have [iaoheo Mm, C..#)=,(n, mM, C..). And thus we may proceed in general until we arrive at a simple de- finite integral containing only one arbitrary constant and the indices NAN, . . . Conversely we may obtain a complicated definite integral in many cases from a simple one, by multiplying it by constants raised to the powers of certain quantities contained as indices in the integral, as- signing successive values to those indices, and then summing the re- sulting series. Thus the integral (123), we E dé cos 0 “0 pcos 0(8+ cos tan 0) —\ sin @ sin tan 0 ' (1+ 26 cos tan 0+ f*) (A sin? 6+ pn? cos? 6)’ was obtained from the definite integral [? cos’!6dé@ cos (¢ tan 8+ (n—1)@) 0 by a process of double summation. These considerations show us why _the method of summation is of such great importance in the evalua- tion of definite integrals. I now hope to prove, as I stated in the last paper, that every func- tion of an algebraical magnitude may be regarded as a centre from which systems of definite integrals emanate in all directions like rays from a star, in such a manner that the value of each integral is equivalent to the original function transformed by a known symbol. Let J (@)=Apt Aye+ Aga? + Age? +... Then 4. SA +5. 4. Agi +6.5. Agett+ ...=f''(#)—2A,—2.3. Aga; n+2 ; 2 or since n(a—1)= | dO cos” 8 cos (n—A4) 0, i) ~= é we shall have 26,2 -5- at dé} A, cos*6+ A, cos? 6. cos 0. 2x+ A,cos® 6 cos 20(2x)?+ ...} =f" (a) —2A,—6Agz ; 7 : 23 (¢ a or putting a=3, el do} A, cost 0+ A, cos? Oc + A, cos Oc%9 4 ., .? 23 (5 . | +=| d0{ A,cost0 +A, cos® 0c” + Agcos’de + J =f" (2) —2A,—BAs. 332 Mr. W. H. L. Russell on [Jan. 27, Hence we have Boia wna 5. n : a ~ A0{ e—¥9F(cos Oe!®) + f(cos Oe-7*) } =" xe dé{ A, cos 40+ A, cos @ cos 36+ A, cos? 6 cos 20+ A; cos* 8 cos 0} ee 2A, —SA,=—"( A, FAs +fL—2A,—3Ag. Hence we shall have :-— [Paot e— #9 F (cos Oe!*) + e*9 fF (cos Oe—*) } = Ft’) . (138). 0 7 This formula was obtained by differentiating f(x) twice, but similar formule may be obtained by differentiating any number of times. By analogous processes we may obtain likewise the following in- tegrals :— 10{<-s#/ (cost 0c) + et f(cost 0e~2)} sl of aval e—“9F (cos? Oe2 ) + #9 f(cos2 Oe—2 )$=5 4 of 'T=—— =f = Me 8.) 2! 21/9 DAO (134). This integral requires the evaluation of Tv fe cos” 6 cos BAdé 0 when 8 is greater than », and consequently the usual formula does not apply. We may, however, proceed thus; since [ d@ cos” 6 cos BO=2 [dé cos”*! 6 cos (B—1)0—$ /dé cos”*! 6 cos (B—3)0 —f dé cos” 6 cos (B—2)0+/ dé cos’t* 6 cos (B—2)0 (135), we are able by successive reductions to reduce the required integral to known forms. | 2 10 low. cos 0 cos? Of eA (+48) foils +4) Bt Gao) fe-2i oD) 0 =79(1) where $(x)=/f/ff («)du* (136). — eS fe-8') =irp(1), where $(a) =/f f(w) da’, Spann (er fe" . sin 5 (eq fe (137). and © is the quantity defined in the fifth paper of this series 1881.] certain Definite Integrals. 333 a ; i \ dé cos? 0{ fe°™ a4 foc O37 | ofc Se prt} ag. (138). 0 [do cost of feome femme} — 71 fe+$ fal. pee: ASO E 0 | © 7 etef(2.sin zei(Z+*)) +e *irzf(2 sin xe i(Z +2) ) 0 (a? + x?) (b? + a?) (c? +27)... (+27) ma). tee) Seo. ay et ons Similarly we may find Bc Ke sina (> +2)) — ¢-2iref (2 eineiils zt )) Seen 610. GEOSTAND... +e) 6 _ ,ri6 : O _.¢7+9 ciag(2 siti 5¢ (+) fey(2 sin 5 )) Qrf(a—1) oe i 2). i 1—2a2cosd0+2* 1—2? Cee Similarly we may obtain :— 6 7+0 caf(2 Sit 5 Gs 2 ))- e 170 2sin see )) d@ sin Pc See Ne ae aoe ate (143). 0 1—Za cos 0+ a* {; eet esi sin awe! Gate dirazf (2 sin avei(5%)) (144) 0 (a? + 2?) (82 +27) (q?+22)...Q2+2%).cosaw © [eae. erirarf (2 sinavei(G*™) 4 en Tae? sin awe7i(F ot) a (145) 0 (a? + a) (B? +27) (4? +22)... (A® +2?) . sin aw Ve ree) Ecos Oe) ee pe wey 0 a“ cos” 0+ a sin? 6 ax ata NY ae \a gell=) 2s oem) CR) —70)). 2. 6 These formule may be greatly extended. I add afew examples of their application to particular cases :— OF € 60S? 6 Cos 26 Q as [avs Eels os Onin) Jain Sree ieee Sk aca A x” cos? 0+ a? sin? @ Qax 334 Mr. W. H. L. Russell on [Jan. 27, 7d0 dO log. (1+ 2a cos” 6 cos 20+? cos*@) _ ae ee (2+a)2?+a2x2 (149) x 2“ cos? 0-+a? sin? 0 an > ‘(e+a)2 é de sin 0 _@ fe re 1422 cos 0422 72° =, ee, be (150). cos @ ae) Ge ie de . i sin aes sin et — « e s Qo e a © « . i: = i) (151) nee) do WEE tseoes tees \\> Vv J (1+ 2a cos 0 +a°)—(1+a cos 0)= ya(VIFa-) . (152). In my last paper I gave the integral \" ao sin 7 0 Bae Ree a oe Sor 132). Jo 1—2ecos@+2? a) It is obvious that by a similar process we can find | ign ACOs TY FexGlss): | * doi. Se ee 9 il—2asiné+2* 0 l—2asiné+2* ; remembering that 1—2zacos ie -- 0) +o2=1+2asin 0+ 2. Also since [Fore +17 dé cos r 0 —74/ dé cos r@ — {Fee (at+beos@)” bj(a+bcos@)""! b)J(at+bcosée)” (a+b cos @)* o a os eae an et Oe dé sin ré —Fal d@.sinrg —|\Fen b (a+bcos@)* 6)(a+bcosé)*1 (a+b cos 6)" (a+b cos 0)” (156), | d@ cos r0 | d@. cos r@ ‘2 (a+bsind)” bjJ(atbsiné)*! b)(atbsind) | (a+bdsiné)* (157), — =| dé sin ré =| dé sin ré [gexec V(a+bsiné)* bJ(atbsiné)” bJ(a+bsine)"! J} (a+bsine)* (158), it is manifest that :— 7 cos ré 7 sin r0 - d@—__—~—______. . (159), do 2s eee \ (1—2a cos 0+ a”)” ee \ (1—22 cos @+2?)* Cy 1881.] certain Definite Integrals. 339 ['2. aes 4C6h), [40 gee, _ (162), 0 0 —2asin O+a*)” (1—22 sin O+a*)” may be reduced to integrals 132, 153, 154, and other known forms, and that consequently (resolving into partial fractions) [" 2 cos 70 (163) (1—2a cos 0+ 27)™(1— 26 cos 0+ 67)”. .. (1 —2d cos 0+)” ; ae) sin 70 (164) Geo cos 0+ a”)”"(1—28 cos 6+ B?)”...(1—2A cos 8+ \?)* ; "8 a em NEY GY) ee 2asin 0+a*)”"(1—28 sing+f?)”...(1—2rsin 9+22)* ‘ Yd sin r0 GE mr eM a cc nce Se a ea A RR iE VOL 8 (| f (- (1—2a sin 0+4?)"(1—28 sin 0+ B?)”...(1—2) sin 0+ )?)" ES) may be ascertained. We may also find 7 fa) re 1 a(2 5 doz Ep at og COs 5 = (167) oF, oN8) nN | M(l0e “) (Jog «) =(n*+3n3+5n?+4+2n)E(n) ~. (168). 1 @ € If we expand the denominator of the integral er Yip or Were ee ae rl \,° 1— Omeosemam a Ler n Ce) and integrate the terms in succession, we shall have to determine the integral series of the form 9 “” a? a a mune a pena Te apenas which may always be found, when the values of (m) and (7) are as- signed, from the expanded form of log. (1+) by the method of summation of the equidistant terms of series. Similar reasoning will apply to eee... (170). [ao . cial, COS ati aft ( 1—2a cos 6+ a? ( : ) TD 9x sin 0+ a2 (L21) gee nO ee ib 1—2esin 0+ 2? Ci) This method of summing the equidistant terms of series may be applied to the determination of the values of other integrals, as for instance 336 Mr. J. W. Hulke. On the Polacanthus Foxii. [Jan. 27, ™ d0 0 sin @ cos” 6 7 cos 26+. cos 60 eG ieee eae @ LS) dé log, cos 0 - ae ater mr BY!) \ 1—k cos® 0 Ce i os 1—2za cos 80+ 2? om) lda. ym | Ut a (175), with many others. ol—kat (Received February 4, 1881.) I have received permission to write down formula (132) thus amended :— l—2 lta 2 r—1 = (a8 i 1! ( —*)\. tail ya)ts 7a)? | 7 sin 76d0 cog o——) ik ol—2acos@+a? 1—2? a” Ss III. “ Polacanthus Fowii, a large undescribed Dinosaur from the Wealden Formation in the Isle of Wight.” By J. W- HULKE, F.R.S. Received January 3, 1881. (Abstract. ) A description of the remains of a large Dinosaur, discovered in 1865 by the Rev. W. Fox, in a bed of shaly clay between Barnes and Cowleaze Chines, in the Isle of Wight. Head, neck, shoulder- girdle, and foreribs were missing, but the rest of the skeleton was almost entire. Some of the presacral vertebre recovered show a double costal articulation. In the trunk and loins the centrum is cylindroid, relatively long and slender, with plano-concave, or gently biconcave ends. Several lumbar centra are ankylosed together, and the hindmost to the sacrum. The sacrum comprises five relatively stout and short ankylosed centra of a depressed cordiform cross- sectional figure. The front sacral vertebre have a stout short centrum. The limb bones are short, their shafts slender, and their articular ends very expanded. The femur has a third trochanter, and the distal end of the tibia has the characteristic dinosaurian figure. The back and flanks were stoutly mailed with simple, keeled, and spined scutes, and the tail was also sheathed in armour. The animal indicated by these remains was of low stature, great strength, and probably slow habits. It is manifestly a Dinosaur, and is considered to be very nearly related to Hyleosaurus. 1881.] On Harmonic Ratios in the Spectra of Gases. 307 IV. “On Harmonic Ratios in the Spectra of Gases.” By ARTHUR SCHUSTER, Ph.D., F.R.S. Received January 10, 1881. It would be a matter of the greatest importance if we could dis- cover an empirical law connecting together ‘the different periods of vibration in which we know one and the same molecule to be capable of swinging. According to the most simple supposition the vibrations might be harmonical overtones of one fundamental note. Various attempts have been made to prove that such indeed is the case, and that the wave-lengths of different spectral lines bear to each other the ratio of two comparatively small integer numbers. M. Lecoq de Boisbaudran and Professor Johnstone Stoney, especially, have dis- cussed this question; the wave-lengths used by the former do not possess the accuracy necessary for a final settlement of the point, but Professor Stoney has, in the case of hydrogen, shown that three out of the four lines in the visible part of the spectrum have wave-lengths, which, to a high degree of accuracy, are in the ratios of 20 : 27 : 32. I have occupied myself at various times during the last ten years with this question, and have naturally accumulated a large quantity of material. About three years ago, however, I came to the con- clusion that only a systematic investigation could lead to a decisive result. In any spectrum containing a large number of lines, it is clear that, owing to accidental coincidences, we shall always be able to find ratios which agree very closely with the ratios of small integer numbers. We can, however, by means of the theory of probability, calculate the number of such coincidences which we might expect to find on the supposition that no real law exists, and that all the lines are distributed at random throughout the whole range of the visible spectrum. If, on calculating out all fractions which can be formed in a spectrum by any pair of lines, the number of ratios, agreeing within certain limits with ratios of integer numbers, greatly exceeds the most probable number, we should have reason to suppose that the lines are not distributed at random, but that the law suggested by Messrs. Lecog de Boisbaudran and Stoney is a true one. I have been engaged during the last three years in discussing some of the spectra in the manner indicated, and I now wish to lay the results of the investigation before the Royal Society. I took the spectra of the following elements; the numbers in brackets indicate the number of lines for each body :— JW eyeaareisinbnen Brae o a om 6 (7) SOCUITLIN, sieueplasueyare ict oveeaen. (10) COO We ira aan eine ore: (15) TEE OnD RIPE Comic eg CII (26) 338 Dr. A. Schuster. [Jan. 27, I have only taken such lines as are found on Angstroém’s map, and I have compared the ratios of any two lines with the ratios of integer numbers smaller than 100. These latter ratios were calculated out to six decimal places, and arranged in order of magnitude in a table, to which I shall refer as the Auxiliary Table. I have adopted two methods of comparison. The first is best explained by an example. The wave-length of the less refrangible of the two yellow- ish-green sodium lines divided by the wave-length of the less refran- gible of the two yellow lines gave the ratio.............. 964760 On referring to the Auxiliary Table we find that. this ratio les tbebweem n'a. ets uate eee Sees meer 55+57= 964912 ING re ele enese Nokia ehate t auat State ache cae eee eras toe 82+85= -+964706 The difference between these two fractions being.......... 000206 The difference of the fraction in the sodium spectrum with the nearest fraction of integer number is.............. 000054: The ratio of these two differences 54206 is found ..... "262 Similar ratios were formed for all possible fractions in the sodium spectrum. Now, if the lines in spectra are distributed at random, we should expect the ratio of the two differences to range indis- criminately between 0 and ‘5; the mean of all of them coming near “25. If, on the other hand, the law of harmonic ratios is a true one, ‘we should expect a greater number of small fractions, and hence the mean should be smaller than -25. The results are given in Table I. The second column gives the numbers of fractions for each spectrum, and the third the mean values obtained, which, as mentioned, ought to be near ‘25, if the lines are distributed at random. Table I. Number of Mean value © ee lone. fractions. of ratios. ee Magnesium ........ 18 °2626 "0229 OCHS Sas esas otico 40 "2399 "0154 Copperas. aac e 101 "2430 "0097 Barve sgee cents lye 303 "2892 ‘0056 Mivony's Sil cee aus se 10404 "25138 ‘0010 Meare: 10866 °2514. Nothing could be more decisive against the law of harmonic ratios than this table; three out of the five elements considered, including the two containing the greatest number of lines, give a mean value greater than °25. In order to see how near to this value we should expect the mean to come if no law connects the different lines, I have given the probable 1881. | On Harmonic Ratios in the Spectra of Gases. 339 deviation from °25 in the fourth column. The term probable in pro- bable deviation is here used in the same sense as in “ probable error.”’ It has been calculated by means of the approximate formula— a ules 3s 6 . Ae 2a where a=°25, s=the number of lines in each spectrum, p is the probability that the mean value les between + 6; for p equal to one-half, 6 is the probable deviation. It will be noticed that the actual deviation never differs much from the probable one, but that it is greater for the two elements having the greatest number of lines. If, therefore, any deduction is to be drawn from the preceding table, it is that the ratios formed by two given lines rather seem to avoid harmonic ratios. The method just explained, and which has given us such decidedly negative results, I believe to be very well adapted for the discussion of spectra which have a comparatively small number of lines; but the iron spectrum may be examined by a more direct and complete method. We may directly calculate how many fractions ought to agree within certain small limits with harmonic ratios if no law exists, and counting how many do thus coincide. I have found, for instance, twenty-eight pairs of lines which coincide within limits so narrow that they can be easily due to errors of measurements with fractions, the denominator and numerator of which are both smaller than 10. This number might appear large at first sight, and some support for the law of harmonic ratios might be derived from it. But the cal- culation gives the larger number 32 as the one we ought to expect, if all the lines were distributed at random; so that here, also, the frac- tions seem to avoid rather the harmonic ratios. A little difficulty is experienced in fixing the limits within which we may consider a coincidence to have taken place. They must depend, of course, on the accuracy which we assign to Angstroém’s measurements. I thought it best to work out the results with two different limits, one of which was half as large again as the other. We gain a decided advantage in classifying the results for two limits. It is in fact equivalent to using a third method of discussion, for supposing the spectral lines to be distributed at random, the number of coincidences found should be proportioned to the limits chosen. If, on the other hand, the law of harmonic ratios is correct, the narrower limit should relatively show the greater number of coincidences. The limits taken were— + °0000505. and. + *0000755. 340 Dr. A. Schuster. [Jan. 27, so that two lines were said to have the ratio of 3 : 4, for instance, if in the first case the ratio lay between °7500505 and °74995195, and similarly for the second limit. : If the measurement of the least refrangible line is correct, an error of 1 in 20,000 made in the measurement of the most refrangible line would correspond to the narrower limit. The results are given in Table II. In the first row all fractions were taken into account the denominator of which is smaller than 10; in the second row, the denominator is between 10 and 20, and so on, for the other rows. The columns headed ‘‘ calculated,” give the number of coincidences which we should expect on the supposi- tion that the lines are distributed at random. The formula employed will be proved in the Appendix. Table II. Limits + *0000505. Limits + ‘0000755. | Observed. | Calculated. Observed. Calculated. Q=1O. ee 48 | 52 64 77 1O-220 ss os6esn | LEO | 206 250 | 308 2030 co were 329 363 4.69 544 © DO—4W 6 od ooo 478 | 521 664 779 AQ 5O0se aoc cx 625 | 679 912 1015 Fy O=—=6 0 seers 777 | 837 1163 1251 RI" sac csc 886 968 1318 1447 O==SOe Gg daoaoe 924 896 1337 1340 S090 ee ele 667 629 989 940 90005. ak 253 241 393 361 Motalitc sek ne 5167 5392 7559 8062 At first sight the result seems again decidedly against the theory of harmonic ratios. For all fractions with denominator smaller than 70, the calculated coincidences are in excess of the observed ones. There seems, however, to be a greater number of ratios than we should expect, which agree nearly with fractions, the denominators of which lie between 70 and 100. If we compare the results given for the two different limits, we find that the smaller limit gives results decidedly more favourable to the theory than the larger ones, and that, as has been explained, is an important fact which cannot be left out of account. In the following . Table (III), I have compared the number of coincidences for the smaller limit with those calculated from the larger one, on the sup- position that the coincidences are proportional to the limits, as they ought to be if no connexion exists between different lines of the same spectrum. It will be seen, that with the exception of two cases, one 1881. ] On Harmonic Ratios in the Spectra of Gases. d41 of which is very insignificant, the number of coincidences for the ‘smaller limits is in excess. Table III. Observed for Calculated from smaller limit. larger limit. OSM ER ASIN LOLs AS 10—20.......... SOME et Oe ae 167 20—30.......... Bs ie Ra ees 314 30—40.......... AN See AEA ge 44,4, AOR OOS sia ee OQ5A 2 KW 610 HOR O0Mee uo. Ret ELL RTE 718 60—70.......... SSO: Ate Nog 882 FO-=80} 0 Ns. ORANG seit ee ee 894, SO 90. eee COMM Rh cane 662 90—100.......... DOO h, Bie k 263 5167 5057 The fact that the number of coincidences, though falling short of the calculated values for both limits, is relatively greater for the smaller, suggests the possibility that still narrower limits might give results which are still more favourable to the theory of harmonic ratios. ‘This indeed is the case. I have counted for all fractions, the denominator of which is smaller than 30, the number of coincidences for a series of 8 limits. The results are embodied in Table IV, and ‘show that there is a tendency of the fractions to aggregate into the compartments for:‘smaller limits. With the exception of the first and Jast numbers, there is a gradual decrease of coincidences as we recede from the harmonic ratios. Table IV. Limits + ‘0000. Number of coincidences. OOO 209 SU lee tals “i OFS Gh, ies Ses Oe 85 OS 20D Ge Go. seks 78 DAS 5) SS) Senet Laue 70 Bo Go! FL eas Da 68 A= —O9O 1h bse Se ins 66 DI ——O9 Oe) 1.) 1s SMe ies 56 COSCO? SL petoR awe 4] ‘We have now to reconcile two apparently opposite results of our calculations. On the one hand it was found that the coincidences with harmonic ratios are fewer than we should expect from the theory 342 Dr. A. Schuster. [Jan. 27,. of probability, and on the other hand the results obtained with different limits showed that the smallest always gave the most favour- able result. The regularity with which this latter fact appears in Tables IIL and IV, proves it not to be accidental, and if not accidental, it can only mean that the law of harmonic ratios is at least partially a true law. The following explanation has occurred to me as possibly account- ing for the facts. We may suppose the harmonic ratios really to: exist in appreciable numbers, but to be chiefly confined to fractions, the denominator and numerator of which are larger than those we: have taken into account. The fractions, for instance, formed by integers between 100 and 200, if arranged in order of magnitude in our auxiliary tables, would fall generally about midway between the fractions formed by the smaller numbers. Any coincidence with the fractions formed by the higher numbers would reduce the number of possible coincidences with the fractions formed by the smaller numbers, and hence we should have the effect which actually exists, of a number of coincidences smaller than that given by the theory of probability. If, now, in addition to these coincidences with fractions formed by higher numbers, we should have a small quantity of real coincidences with the fractions which we have taken into account, the increased quantity of coincidences for small limits over those of larger limits, would be explained. This explanation might be supported by the fact that, for fractions formed by numbers between 70 and 100, the coincidences observed are more numerous than those calculated on the supposition that the lines are all distributed at random. It must, however, be remarked that a similar effect might be produced, if any unknown law existed, con- necting the lines together, a law which in special cases reduced itself to a law of harmonic ratios. That some Jaw hitherto undiscovered exists I have no doubt, for just in the cases where we have reason to suppose that different lines belong to one system of vibration, we cannot find any coincidences with harmonic ratios. The lines of sodium, for instance, are all double; yet in the set of lines given by Thalén the two components. approach each other much more rapidly as we pass to the more re- frangible end of the spectrum than they would if the lines were con- nected together by the harmonic law. In the additional sets described by Professors Liveing and Dewar no regularity exists in the distance of the two components. A similar remark applies to the four triplets of magnesium lines. The triplets resemble each other in so far as the middle line is always nearest to the most refrangible line; but the resemblance is only a general one, and there is no absolute relation between the relative distances in each triplet. 1881.] On Harmonie Ratios in the Spectra of Gases. 343 Taking all these considerations into account, the following seems to me to be a fair summary of my results for the iron spectrum :— 1. There is a real cause acting in a direction opposed to the law of harmonic ratios, so far as fractions formed by numbers smaller than seventy are concerned. 2. After elimination of the first cause a tendency appears for fractions formed by two lines to cluster round harmonic ratios. 3. Most probably some law hitherto undiscovered ewists, which in special cases resolves itself into the law of harmonic ratios. The subject is of sufficient importance to make further investigation desirable. We might, for instance, confirm the laws which we have found to hold in the iron spectrum by treating in the same way some other spectrum having many lines, as those of manganese of calcium, But it seems to me to be more promising to increase the accuracy of measurement in the special cases where harmonic ratios have been found. There are, for instance, two lines in the iron spectrum which are in the ratio of 2:3. By using a diffraction grating we might test this coincidence to a great degree of accuracy by seeing how far the more refrangible line in the third spectrum coincides with the less re- frangible line in the second spectrum. Account, of course, must be taken of atmospheric refraction; reflecting surfaces only ought to be used. I hope to try this plan before long, but in order that others might have the same opportunity, I append a list of all lines which are nearly in the ratio of some fraction formed by integer numbers smaller than ten. Angstrém’s numbers corrected for atmospheric refraction are used. The table explains itself, but it is perhaps wise to remark again that, the number of these coincidences is not larger than one would expect by the theory of probability, and that therefore all of them may prove to be accidental. Fraction. Calculated. Observed. Difference. 6009°33 7) 8 3) 4006 °22 4.006°03 — 19 5603°40 3: A 4202°55 4202°74 qe AL) 5098°88 3: 4 4199°16 4199°16 -- 00 5576'59 3: 4 4.182744: 4182°53 +13 5340°82 3: 4 4005°62 4006°03 +41 6302°47 4: 5 5041°98 5041°67 -- ‘31 5430°47 4: 5 43.4:4°38 4344°33 — 05 034082 4: 5 4.2'72'66 4:2'7 2°54: —'12 5264:07 4: 5 4211°26 4211°09 — 17 5227°85 4: 5 4182°28 4182°53 +°25 519327 4: 5 415462 415496 +34 6231°66 5: 6 5193°05 5193°27 + 22 6003°91 5: 6 5003°26 5003°50 +24 0987°99 5: 6 4989°99 4989°85 — 14 VOL. XXXI. 6) d44 ° Dr. A. Schuster. (Jan. 27, Fraction. Calculated. Observed. Difference. 5169-93 5: 6 4308-28 4308°45 4:17 6137°53 Ra Uy 4383-95 4384-04 +09 5430°47 Rox 4654-69 4654:9 +2 528427 Gi 7 4529:37 4529°35 —-02 5140:20 Ge 27, 4405°89 4405°50 —-39 6137°53 7: 8 5370°34 5370°66 4°32 6066:38 7: 8 5308-08 5308'11 +03 | | 5383-99 7: 8 4710:99 4.71080 —-19 5271-06 738 4612°18 4612-08 SoG 5984-66 7: 9 4654-74, 4654-9 +2 5447-57 72 9 4237-00 4236-75 —-25 537216 7: 9 4178°35 4178-28 —-07 5341°85 ioe) 4154-77 4154-96 +19 5328:90 wa 19 4144-70 4144-30 —-40 | 6003°91 7:10 4202°7 4, 4202°74 +:00 6009°33 8: 9 5341-63 5341 ‘85 4°22 5616:24 8: 9 4992-24, 4991-89 =e | 4633°47 Sino 4118°64 4118'94 +°30 6192°45 9:10 5573-21 55 73°35 4°14 5603:40 910 5043-06 5042-71 —-35 4692°02 Oa 4222'82 422.2'88 +06 4707-92 9:10 4237-13 4236-75 —:38 4787-23 O10 4308°51 4308°45 E06 5233-71 9:10 4710°34, 4710'80 4°46 APPENDIX. The problem which we have to solve may be stated as follows :— Given acertain number of quantities distributed at random between two fixed limits; form the ratios between every pair of them, and find the expectancy for the number of these ratios which shall within certain small limits agree with a given fraction. In the first place, we remark that without detriment to the generality of the problem, we may assume the lower of the hmits within which all the quantities are lying to be unity; for if it is not, we may by means of a common multiplier to all quantities reduce it to unity. Let « be the given fraction with which all the ratios are to be com- pared, and let A be the higher limit which none of the quantities shall exceed. Assume at first A to be smaller than the square of the reciprocal of « Divide the range A to 1 into two compartments; the first from A to 1 and the second frome to 1. Let there be ¢ a a quantities which I shall call a), a,,...in the first compartment; and let there be r quantities 0,, by, ...in the second compartment. None of the quantities within one compartment can form amongst them- selves ratios which shall be closely coincident with a: say a+6. 1881.] On Harmonic Ratios in the Spectra of Gases. 345 If there is only one quantity, a, in the first compartment, 0b is given by the equation— —w AO b=aatéa. Hence, if there is only one 0 which can range between and 1, and a must lie between a («+6) anda (#—6), if there is a coincidence with the given fraction, the probability of such a coincidence is P70 maa If there is more than one quantity, a, in the first compartment, we observe that these quantities may lie so near together that one and the same 0 can have, within the limits within which we count coin- cidences, the required ratio with more than one of the quantities, a. If these quantities, however, are not sufficiently close together to admit of any such double coincidence, the probability that one b should have the required ratio with one a is 2a sai Oe 6(a,+a,+ chee it). Call the sum in brackets s;. If we drop the limitation that b should not possibly have at the same time the required ratio with more than one a, the expression just found will not any more represent the probability of a single coinci- dence, but it will represent the expectancy for the coincidences. For in the most general case there is a certain range, A, within which D may lie in order to have the required ratio with one of the quantities, a; there is a range, A,, within which a double coincidence will happen, and so on: hence the expectancy for the coincidences is (ROECON SEES UNG Sy Lea a but the expression in brackets is always equal to 2684, and hence the expression which we have found will represent the expectancy if there is only one quantity, b; for r quantities it is 26a 1l—« Sts We have hitherto supposed that the quantities, a, are at given fixed places, or that s; has a certain given value. Let pids;, be the proba- 2c 2 346 On Harmonic Ratios in the Spectra of Gases. [Jan. 27, bility that the suin of all the quantities, a, shall lie between s; and si+ds;, then the whole expectancy is a al pesialst. The integral represents the expectancy for the sum of ¢ quantities all equally probable between 1 and A, and this expectancy we know to We ON Bye a( es Hence the required expression is— Aa+l a be— (io In the actual case neither r nor ¢ are given, we only know their sum 7; hence we must add up a number of expressions of the form we have found, varying r and ¢, and multiplying each with the proba- bility that the particular distribution actually exists. The probability that there should be ¢ out of m values in the first compartment is— n! (Chere) t!(n—#)! a®(A—1)" giving ¢ successively all values from 1 to »—1 we find for the whole expectancy — sAetl 1 t=n—1 t(n—t)n! Py | t gece n—t =.) #2, HOE and adding up under the summation sign, the expression reduces to— Nl Bee? A 5 CRS er a which is the complete expectancy. We have assumed that A is not larger than the reciprocal of the square of «, and we may now extend the formula to larger values of A. Imagine a quantity B smaller than si and larger than i and let a” (44 A gradually increase from B to e Divide the whole range A to 1 into a two compartments, one from A to B and the second from B to 1, then ifa given number of quantities is in each compartment, I can calcu- late the whole expectancy by knowing :— 1881.] Mr. J. Hopkinson. Dielectric Capacity of Liquids. 347 1. The expectancy for the coincidences between two quantities in the second compartment. 2. The expectancy for the coincidences between one quantity - in the first compartment and one in the second. Now A is supposed to increase gradually from a value smaller than 3 2 toa value larger than = As long as it is smaller, the result must a a be the same as that we have previously obtained, but none of the quantities which enter into the calculation show any discontinuity, as A passes through the value = and hence the formula cannot change ao~ at that point and must be true as far as the value iB or as B may be in ; (42 the limit equal to sa we have extended our formula to all values of A a smaller than as It can be further extended in the same way and - | must in fact be true for all values of A. VY. “ Dielectric Capacity of Liquids.” By J. HopxKinson, F.R.S. Received January 6, 1881. (Abstract. ) These experiments have for object the determination of the refrac- tive indices and the specific inductive capacity of certain liquids, and a comparison of the square of the refractive index for long waves and the specific inductive capacity. In the following table are given the results obtained for refractive index for long waves deduced by the tormula p=, +o, the square of fg, and the observed values (K) of the specific inductive capacity. Hoo K Petroleum spirit (Field’s)...... 1-922 192 Petroleum oil (Field’s)........ 2-075 2°07 (Common): 2078 2°10 roles lubricating oil (Field’s) 2086 Delis Turpentine (Commercial) .... 2°128 2°23 Casto ole. wih 2s. Fails Oe tee 2°153 4°78 Sermon iat. Poa w ies 2°135 3°02 ion OPN os ox le lowes woraudlace 2°131 3°16 348 Mr. J. N. Lockyer. [Jan. 27, It will be seen that while for hydeneantons 125 =K, for animal and vegetable oils it is not so. VI. “Note on the Occurrence of Ganglion Cells in the Anterior Roots of the Cat’s Spinal Nerves.” By E. A. ScHAFER, F.R.S. Received January 11, 1881. Ganglion cells are of constant occurrence among the nerye-fibres of the anterior roots of the cat’s spinal nerves. They are generally to be found in that part of the anterior root which passes by the ganglion which is seated upon the posterior root. They are not necessarily situated next the ganglion; but are often imbedded in the middle of the anterior root, or found lying along its anterior margin, and there- fore as far removed as possible from the ganglion upon the other root. Moreover, they sometimes occur in tke anterior root before this has come in contact with the ganglion, just as isolated ganglion cells are occasionally to be found in the posterior root, some little distance on the spinal-cord side of its ganglion. The cells in question, although not in any sense numerous, are to be found in most longi- tudinal sections of the anterior roots, but they seem to be especially abundant in those of the lower dorsal and lumbar nerves. They resemble on the whole very closely the ganglion cells in the spinal ganglion upon the sensory roots, but it has not hitherto been possible to make out their mode of connexion with the nerve-fibres. I have sought in vain for ganglion cells in a similar situation in the nerve-roots of man, the dog, the rabbit, and the mouse. The evidence, therefore, appears to be against the existence of any relation between the occurrence of these cells in the anterior root and the phenomenon of sensibility in that root, known as “recurrent sensa- tion,” for the latter has been observed in animals in which I have been entirely unable to detect the existence of the cells in question (e.g., the rabbit). VII. “On the Iron Lines widened in Solar Spots.” By J. NorMAN LockYER, F’.R.S. . Received January 13, 1881. The observations put forward with reserve in my last communica- tion to the Society have now been confirmed. In the fine spots visible on December 24th, January Ist and 6th, many lines in the spectrum of iron were seen contorted, while others were steady. The facts are given in the following table :—- 1881.] On the Iron Lines widened in Solar Spots. 549 The iron lines Iron lines, visible in the same indicating motion. field of view, steady. Dec. 24, 1880. . 5403 -2 D404 Cae fleece sale t 5410 °0 TAO O SOs ape eget s cae bh. 5414 °5 5408 °8 9996 *0 9970 °5 DOS) ene peat a 5366 °5 4919 °8 EOI Sens cc. eNR NEA 4923 °0 5 ADA diese 2 Mee ett Pe 5269 °3 MOM OL Ei Meee es oN 5268 *5 In another part of the same spot— BOGS Sak teW., Yo. MW Saiaie « 5323-5 ROR L et Ghee gee 5327 -0 (double). ermpeies! 50085 oo... ele 5269 8 5827-0 (double).......... 5268 °5 Jan. 6, 1881... 4919 °8 AMO e OL Gis TEC le ats 4.925 °5 * All lines between X 5323 °5 and 5410 ‘0 except 5382 °1. It is to be noted, that these observations furnish us with an instance of inversion similar to those frequently obtained in our observations of the most widened lines in spots. The inferences to be drawn from these observations, and those on which we are now continuously engaged, must be matter for future communication. But I cannot resist calling attention to the crucial nature of the evidence, at least as regards iron, in favour of the view first put forward by Sir B. Brodie, whom we have so recently lost, that the constituents of our terrestrial elements exist in independent forms in the sun.* ; I have thought it right to send in a record of this work at once, with a view to induce other observers to follow the continually vary- ing phases of the spots during the approaching maximum. The observations have been made by Mr. H. A. Lawrance, and con- firmed by myself in the majority of cases. * Tn this spot the D lines indicated motion and did not retain their parallelisin. + Lecture delivered before the Chemical Society, June 6, 1867. 300 Presents. [Jan. 6, Presents, January 6, 1881. Transactions. Helsingfors:—Société des Sciences. Acta, Tomus XI. Ato. Helsingforise 1880. Bidrag till Kannedom af Finlands Natur och Folk. 32a Haftet. 8vo. Helsingfors 1879. The Society. Societas pro Fauna et Flora Fennica. Meddelanden. 5e Haftet. Svo. Helsingfors 1880. The Society. Jena :—Medicinisch-naturwissenschaftliche Gesellschaft. Jenaische Zeitschrift. Band XIV. Hefte 2-4. 8vo. Jena 1880. The Society. London :—Institution of Mechanical Engineers. Proceedings. 1880. Nos. 2 and 3. List of Members, 1880. The Institution. © Pharmaceutical Society. Journal. Vol. XI. Nos. 520-49. 8vo. The Society. Photographic Society. Journal and Transactions. N.S. Vol. IV. No. 8. Vol. V. Nos. 1-3. 8vo. The Society. Physical Society. 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The Presents received were laid on the table, and thanks ordered for them. The Right Hon. Mountstuart Elphinstone Grant Duff, whose certi- ficate had been suspended as required by the Statutes, was balloted for and elected a Fellow of the Society. The following Papers were read :— I. “Upon the Cause of the Striation of Voluntary Muscular Tissue.” By JoHN Berry Haycrart, M.B., B.Sc., F.R.S.E., Senior Physiological Demonstrator in the University of Edinburgh. Communicated by Dr. Kunin, F.R.S. Re- ceived December 1, 1880. [PLATE 5. | The structure of striated muscular tissue has occupied the attention of many histologists, and various, often antagonistic, have been the views held from time to time since Schwann first investigated this difficult subject. I bring forward with much caution and hesitation any opinions of my own, nor should I venture thus far, did I not consider my views susceptible of direct proof, or disproof, not being matters of mere speculation, which may or may not be true, and which would tend, by their introduction to the literature of the subject, to make confusion worse confounded. In this paper an attempt will be made to account for many of the observed structural phenomena of muscle on simple laws of geome- trical optics, which will, if it be successful, reduce the subject to comparative simplicity. I shall commence by giving a sketch of the views of those physiologists who have especially written upon the structure of muscle. This must not be looked upon as a complete history, for I shall leave out entirely points which do not concern us here. A Short Historical Sketch of the Views held upon the Structure of Striated Muscle-—The writings of Mr. Bowman form the most im- —-1881.] the Striation of Voluntary Muscular Tissue. 361 portant and brilliant contributions to the literature of this subject, and taking him as a landmark, it is convenient to speak of investi- gators before or after his time. Among the former Schwann, quoted by Miller (“ Physiology,” translation by Baly, vol. ii, p. 878), describes the striated voluntary fibre, indicating its shape and size. The cross markings were observed by him, and, indeed, with one or two remarkable exceptions, by all the early observers (Lauth and Wagner, in Miiller’s ‘‘ Archiv fiir Anatomie und Physiologie, und Wissenschaft- liche Medicin,” pp. 4 and 818, of the year 1835). Schwann, with Bauer, Krause, Miller, Home, Valentin, and Milne Edwards recog- nised the important fact that each fibre is composed of a number of threads or fibrille, packed side by side and joined together by a transparent tenacious fluid (Krause), and, moreover, that these threads or fibrille are cross striated, as is the fibre itself. Although Schultze describes the fibrillee as being uniform filaments, he is alone in this opinion, most of his contemporaries recognising the beaded appearance.* The beaded thread was the cause of some dispute, for the question arose, was it a linear series of globules or a moniliform filament? and the final settlement of this must, indeed, have been a matter of great difficulty to those older savants, when we consider the imperfect lenses at their disposal. Krause and others maintained the former view, while Schwann held that which subsequent investi- gators have shown to be the correct one. The fibrillz, according to Schwann, present a very regular succession of bead-like enlargements, darker than the very short constrictions which le between. ‘Thus, before the time of Mr. Bowman, the following important facts had been made out, namely, that the fibre is composed of a bundle of beaded fibrillae cemented together, and that the fibrillz are cross striped, giving the whole fibre a like appearance of striation. Hrroneous views had often, it is true, been advanced, but these had never received general acknowledgment. Mr. Skey (‘‘ Phil. Trans.,” 1837), for instance, considered the fibres to be tubes filled with a soluble gluten, the striz surrounding and binding them together. Leeuwenhoek had a some- what similar view of the construction of the cross striz, and Prochaska considered them as depressions caused by the clasping of neighbouring capillaries and thready tissues. Mr. Bowman communicated to the Royal Society, in 1840, a paper “On the Structure and Movements of Voluntary Muscle,” in which he confirmed many of the opinions of his predecessors, adding, at the same time, much of what was fresh to our store of knowledge. He it was who first described the thin elastic membrane (sarcolemma) covering and ensheathing the fibres, showing how easily to demon- * Consult a drawing by Allen Thomson in illustration of Dr. Martin Barry’s paper on the structure of muscular fibrils, “ Phil. Mag.,” series 4, vol. 5, Plate V, fig. 2. Dy 362 Mr. J. B. Haycraft. Upon the Cause of _—_[Feb. 3, strate its existence, and giving figures of it, which have been copied into most modern histological works. The nuclei of the sarco- lemma he also figured, but what most concerns us is his description of the cross striation. Bowman, I believe, first pointed out that not only can a fibre be split up longitudinally into fibrille along certain dark lines which may generally be seen, even in fresh preparations, but that it splits up transversely along the dark stripes. Hach fibrilla may, therefore, be split up into tiny segments across the dark strie. ‘On the whole, little doubt remains in my mind that the fibrillee consist of a succession of solid segments or beads connected by intervals generally narrower, and I believe the beads to be light, and the intervals the dark spaces when the fibrilla is in exact focus.” His idea of a fibre naturally follows from that just given of a fibriila, and, quoting again from him, we find “a fibre consists of sarcous elements (so he termed the little segments or beads) arranged and united together endways and sideways, so as to constitute in these directions respectively fibrille and discs, either of which may in certain cases be detached as such,” and “the dark longitudinal striz are shadows between fibrille, the dark transverse striz shadows between discs.” Tt will be seen that in one particular Bowman disagreed with Schwann and the older writers, and at the same time with those of more recent date. According to him, the bead was light and the constriction dark, when the muscle was in exact focus, a description at variance with everyone. In the same paper he mentions this remarkable fact, that on altering the focus the stripes were reversed ; he must have examined it—this bears in a most important way on our investigations, to be afterwards described—in the reverse focus of what it is ordinarily figured in. His view of the form, and the split- ting of the fibre, was probably correct, for he described the cleavage as occurring in the narrow part, which appeared to him, focussing as he did, to be dark, and indeed it is often difficult to say which it is, whether dark or light, for, as I shall more particularly mention afterwards, the slightest alteration of the focus is sufficient to reverse the appearance of the fibre. Bowman, moreover, accounted for these light and dark parts of the fibrille, comparing a muscular filament to a glass rod with alternate swellings and depressions, which, when viewed with transmitted light, gives just the same appearance, and from a study of his paper, although it is here somewhat indefi- nite, I judge that he concluded the moniliform shape to be a cause of the striping.* * Bowman, nevertheless, seems to consider the dark stripe of a different structure from the light, not so much from the shading, but from the transverse cleavage. He is not quite definite here, but this is the impression I have gained from a careful perusal of his paper. 1881. ] the Striation of Voluntary Muscular Tissue. 363 Now, this last-named and important discovery of Bowman’s has, I believe, completely been lost sight of, for no mention of it can be found in any modern monograph nor in any systematic text-book that I have examined. The striking points in the paper and in the figures he gives, is the splitting up of the fibre into transverse discs and the demonstration of the sarcous elements as before quoted. ‘This, together with the sarcolemma, everyone connects with the name of Bowman. Modern investigators have worked mostly at the cross striping of muscle, and have found it more complicated than Bowman described, owing, no doubt, to the use of better glasses; while he explained the phenomenon as due simply to the shape of the fibres— believing, however, probably that it was due also to structural differences—modern investigators have introduced hypotheses to account for it, which imply differences of structure along the filament. The reason of this is, if | may express an opinion, that his theory has been completely lost sight of, and that it was followed by the discovery . of startling facts, which at first sight seemed to set it on one side. In discussing the views of modern inquirers, I shall not, in all cases, consider them in the order of their priority, and allusion will not be made to much that has been written upon this subject, which, indeed, may safely be put on one side. The light stripe—dark stripe of Bowman—has been shown by Dobie, Busk, and Huxley to be traversed by a very fine dark band, or rather line, ‘‘ Querlinie,” dividing it into two equal parts. We shall speak of this as Dcbie’s line, or the dark stripe in the centre of the light. (Fig 1, D, Plate 5.) Then, again, the dark stripe is traversed in its centre by a lighter band called Hensen’s stripe.* (Fig. 1, H, Plate 5.) Other bands border this stripe, but as they are certainly not to be seen in all specimens however well prepared, and as we shall presently account for them, they need not trouble us here. As early as the year 1839, Boeck showed that muscle refracts light doubly, which statement was, however, modified in 1857 by Briicke. The latter examined muscles prepared in alcohol by polarised light, and found that the dark stripe (dark in ordinarily non-polarised light) appeared luminous in the dark field of the microscope, and that the light stripes were dark when the Nicols were crossed. The dark stripes, therefore, appeared to be doubly refracting (aniso- tropous), and the light stripe singly refracting (isotropous), the fibre consisting of singly and doubly refracting discs alternating one with another. These observations he verified by an examination of the fibre with thin plates of selenite and mica. The views of Briicke have, in their turn, received considerable modifications which will be understood by reference to a diagram. Fig. 2, Plate 5, expresses * This stripe was also described by Dobie in the “Annals of Natural History”’ for 1849, and it may be called “ Dobie’s light stripe.” 364 Mr. J. B. Haycraft. Upon the Cause of — [Feb. 3, very well the results of my own observations, which I find, are in accordance with those of other observers. (See the ‘‘ Handbuch der Physiologie,” by Dr. H. L. Hermann, 1879, p. 20.) The black part of the diagram corresponds with the portion of the muscle which singly refracts light (isotropous), while the light shaded parts cor- respond with the anisotropous substance. This diagram does not, it will at once be seen, correspoud with the views held by Bricke, for the great mass of the light stripe, with Dobie’s line in the centre of it is anisotropous, the dark band, as with Bricke, being anisotropous. The most recent view is, then, that both the light and the dark stripes doubly refract light, but that there are bands which lie between them and which are singly refract- ing. The appearance which partially warrants such a conclusion I have observed, but I shall endeavour to show hereafter how this may most satisfactorily be explained. It will readily be seen how Briicke’s view, until quite recently accepted, would drive one to the conclusion that the light and dark stripes represent two diffe- rent structures alternating ,in the length of the fibre, and this is corroborated by statements as to the action of staining agents en the tissues. Muscle is readily stained by picric acid, but is but faintly tinted by carmine, logwood, or eosine, although Ranvier, in his “Traité Technique d’Histologie,” states that he has obtained very beautifully stained preparations of insects’ muscle, when using Beehmer’s solution of logwood. According to this observer, the dark stripes as well as Dobie’s lines are stained, while the rest of the fibre remains colourless. Klein in his “ Atlas of Histology” figures the sarcous matter of the dark band clearly tinted, while that of the ight stripe is absolutely colourless. The statement will not be far wrong, that everyone at the present time considers the dark and light stripes as representing two different structures, distinct one from another in their physical properties, for the dark stripe is spoken of as possess- ing a higher refracting power than the light, and chemically, for their compositions have already been hinted at by more than one observer. The dark stripe is looked upon by most as the true contracting part of the fibre, and they are termed the sarcous discs, or “‘ Muskelprismen,” ‘“‘ Hauptsubstanz,” or masses of “‘ disdiaclasts,” and the light stripes as merely connecting matter, “‘zwischensubstanz,” or ‘‘ Muskelkastchen flissigkeit.”’ Dobie’s line—more especially from the dipping down and attachment of the sarcolemma in insects’ muscle at this point-— has been looked upon (Krause, ‘“ Allgemeine und Mikroscopische Anatomie,” section Muskel System, pp. 80—90) as a delicate trans- verse membrane. This view has received the assent of such micro- scopists as Klein and Ranvier, but not of Wagener (“ Jahresberichte der Anatomie und Physiologie,’ Hofmann and Schwalbe) and 1881.] the Striation of Voluntary Muscular Tissue. 365 Rutherford (‘‘Text-book of Physiology,” p. 128), who describe Dobie’s line as consisting of a row of dots. Engelmann, indeed, describes a row of dots on either side of this line. Krause would have us believe that the fibre is divided by these membranes into a linear series of little boxes, each box or casket, “ Miskelkastchen,” containing a dark stripe with (as the membrane lies in the centre of the light stripe) one half of that on either side. Merkel (‘Lehrbuch der Gewebelehre,” Stuttgart, 1877, p. 83), to make the “ Miuskelkastchen” self-containing, affirms that the mem- brane of Krause is double. As to the stripe of Hensen, this is by very many looked upon as still another structure lying in the centre of the dark stripe; it is in many fibres very clearly to be made ont, its border being well defined, and in stained preparations (logwood) it has decidedly a lighter tint than the rest of the stripe. Still some (Krause) look upon it as an indication of the highly refracting power of the dark stripe, comparing the appearance with the light centre of an oil globule. The other cross striz, of which there are many described by some cbservers, but none at all universally accepted, are, as a rule, considered as indicating further complications in the muscle fibre ; indeed, the “‘ Miiskelkastchen,” by most advanced microscopists, although not z5355 of an inch in length, consists of some ten or twelve different parts. We may postpone, I think, in- definitely the consideration of these details. While there is great unity as to the appearance of a fibre during a state of rest, the changes which the fibre undergoes when passing into the contracted condition are not at all understood. Not only does one fail to find among histologists agreement as to the changes in appearance, but the interpretations of these are as numerous as the in- vestigators themselves. All are agreed, that during contraction, the fibre as a whole shortens and thickens, but the changes in form which the cross striz undergo are not understood so well. Klein, in his ‘‘ Atlas of Histology,” maintains the broadening of both stripes transversely, the dark stripe becoming thinner in the long axis, and the bright stripe more opaque. Ranvier (‘‘ Traité Technique d’Histologie,”’ p. 489) states that the only points one can conscien- tiously observe in the contraction of a living fibre are, that a knot or bulging forms, in which the dark bands approximate, being only sepa- rated by Dobie’s line. This led him to believe that the dark bands are the true contracting part of the fibre. Ranvier worked especially with osmic acid, fixing the fibres when at rest, and during contrac- tion. W. Krause (‘‘ Alloemeine und Mikroscopische Anatomie,” p. 92) describes the contraction as follows :—The thickness (in the length of the fibre) of the dark stripe or an isotropous substance remains the same as far as can be seen, while the thickness of the isotropous sub- stance, ‘“ Zwischensubstanz”’ becomes less. From this, he argues that 366 Mr. J. B. Haycraft. Upon the Cause of — [Feb. 3, the substance of the clear stripe, which he considers as fluid “ Muskel- kastchenfliissigkeit,” passes between the little elements of the dark stripe, causing their lateral separation, and therefore broadening and shortening the fibre. Hngelmann (‘“‘ Neue Untersuchungen tber die Microskopischen Vorgange bei der Muskelcontraction,” in “ Pfluger’s Archiv,’”’ Band xvii) is certain that the light stripe during complete contraction becomes darker than the dark stripe, and that there is a period as naturally follows from this observation, when the fibre is quite unstriated. The stripes are in fact reversed, the bright one becoming the darker, and vice verséd. Both stripes narrow, but especially the bright one. Hngelmann advances a theory to account for this, holding that the cause of contraction is the passage of fluid from the isotropous clear stripe into the anisotropous substance; the former shrinks, and the latter swells. Most startling is the view of Merkel (‘‘ Hofmann und Schwalbe,” vol. 1, p. 116), who believes that the dark stripe shifts its position, arranging itself by Dobie’s line, while the light stripe passes to the centre. It is, as will readily be admitted, somewhat difficult to know what to believe, for there is such entire disagreement amoung physiologists as to simple facts, to say nothing of any conclusions which may be drawn from them. Thinking that there must be some simple clue which would solve the whole problem, 1 commenced to work at the subject in the summer of 1878. At the onset the clue was discovered, and the substance of the present paper was written by the end of that year, before I had read for the first time the paper of Mr. Bow- man’s, in the “Transactions” of this Society. My astonishment was indeed great to find in it the first glimmerings of my own opinions, for although the subject had then been worked out but in the rough, and Mr. Bowman had a much simpler problem to deal with, yet undoubtedly he held the same views in the main. My obvious course was therefore entirely to re-write my paper, making every acknowledgment to his already published work. He considered, as far as I can make out, that the light stripe was to be compared with the cement seen in longitudinal fibrillation, between the fibrille, yet he locked upon the striz as being due to the shape of the fibre. From the history of the subject, which has just been given, it will be seen that all observers are not agreed as to the actual appearances of a striped fibre, and especially the changes which occur during contrac- tion, and I hold that they have fallen into great and unwarrantable error in the conclusions (these, indeed, are all contradictory) drawn from these appearances. A fibre has been observed in the field of the microscope, which is marked transversely, as already described, and all modern investigators have concluded that the transverse bands mark the positions of disks (seen on edge) of tissue of different refrac- tive indices and chemical composition, alternating in the long axis of 1881. ] the Striation of Voluntary Muscular Tissue. 367 the fibre. This is, however, purely an assumption which in no way follows. We can also account for all these cross markings in a way which involves no theory, and requires for its appreciation but a knowledge of most elementary geometrical optics. if a small fragment of muscle be teazed out in water, salt solution, or almost any other fluid, and examined in tne ordinary way, with a power of 300 diameters or more, the important fact may be made out (which is the basis of all my future observations), that the borders of ~ the fibres are not smooth, but undulate, presenting wavy margins. @fies 1.) In the fresh unstained preparation there is a halo around the edge of the fibre which masks the crenulated border, yet by carefully adjust- ing the mirror so as to obtain oblique light, or by searching for a fibre partly in the shade of another, this may always be made out; in the case of insects’ muscle, this is, however, always easy to demonstrate, for the fibres are much coarser, indeed, the appearance has been often figured in the works even of recent histologists. Jf the preparation be stained by any of the ordinary dyes, perhaps most readily by picro- carmine, the border is in all cases very distinct, and the regularly sinuous margin is unmistakeable. Now, what is the significance of the wavy outline? It is, as will readily be understood, that the fibre is ampullated, the wavy outline being but the optical expression of such a figure. A muscular fibre is then not a smooth cylinder, but is like the turned leg of a chair, or like the transversely ribbed neck of a common water-bottle in shape. If the fibre be broken up into fibrille, which is very easy, after maceration in alcohol, these are seen to have just the same characters, indeed, a small bundle of fibrils is most convenient for study. It may be well to remark, that the ulti- mate fibrille often show but little cross marking, and appear almost smooth; that is, however, only due to their small size; a good lens will bring out both points. . The above-described appearances may be observed in all the varieties of muscle that I have as yet examined, e.g., those obtained from man, the dog, cat, rabbit, guinea-pig, mouse, frog, mussel, crab, bee, wasp, Dytiscus, Hydrophilus, common house fly, &c., &e. The transverse stripings of the fibre are related to and correspond with the inequalities of the surface. (Fig. 1.) The little elevations at the borders correspond, of course, to the little ridges which run round the fibre, while the dips at the borders are the optical expressions of little valleys running between them. In the ordinary position, the dark stripe marks the position of the ridge, and the light stripe lies in the little valleys, as will be seen on reference to fig. 1, Plate 5. Then, again, Dobie’s lime (Krause’s membrane), which is a faint dark band in the very centre of the bright stripe, runs along the 368 Mr. J. B. Haycraft. Upon the Cause of — [Feb. 3, bottom of the valleys (D in the diagram), and Hensen’s stripe in the centre of the dark band, les on the exact summit of the ridges. GaiMfig. 1.) This position of the stripes in a normal muscular fibre, is the in- variable rule, and the idea at once suggested itself, may not the shape of the fibre itself cause the cross stripings ? Any student of natural philosophy would at once affirm that a structureless fibre of such a shape must. be cross striped, and a glance at the ribbed neck of the water-bottle on the tabie will elicit the same answer from any one. The question we must now determine is, are the appearances seen in the fibre just the same in all their details, as would be produced by a piece of glass, or any other homogeneous transparent substance of the same shape ? Before, however, entering into theoretical grounds, it may be as well to give a full description of what is actually to be seen, for this has yet not been stated. With a structure of complicated figure, such as the one we are con- sidering, it is obvious that there is no one focus in which it may be described. There is one pretty definite focus for a single speck or thin film, but even when examining a simple cylinder, it is evident that when the borders of it are clear and distinct, the upper surface is slightly out of focus. We shall see, that in the case of the muscle, although there is one position of the lens when the parts are very distinctly seen, and in which they have mostly been described, yet that on slightly altering the focus, the appearance is changed. These changes we must carefully study. For this purpose we may select the large muscles of the thigh of a rabbit; stretch them ever so little upon a piece of wood, and place them for some days in 50 per cent. alcohol. A high power is required for their examination; I have been in the habit of using a =4-inch of Gundlach, a very perfect lens; a ~4,-inch will, however, do. A smali bundle of fibrils should be selected in preference to a whole fibre for examination. On focussing it becomes at once apparent that on varying the adjustment ever so little, you may bring into focus the tops of the ridges or the bottoms of the valleys which lie between them. Now this slight alteration is sufficient entirely to change the optical appear- ances. First raise the lens until the fibre be out of focus and is only to be seen as a dim streak running across the field, then bring it down until its form and the cross markings are distinctly to be seen (the border is now not quite distinct on a level with the horizontal axis of the fibre). In this position alternating ight and dark bands are made out, but no vestiges of Hensen’s stripes or Dobie’s lines. (Fig. 3, a.) The 1881. |] the Striation of Voluntary Muscular Tissue. 369 dark band corresponds with the valley and the light one to the ridge, or crest. This was the focus in which Bowman described his prepara- tions as far as I can gather from the paper. If the lens be now lowered ever so little, the stripes are reversed, a most curious point, which was noticed by Bowman, but afterwards lost sight of. The dark band now corresponds with the ridge, and the bright band with the valley. (Fig. 3, ¢.) This is the focussing in which it is usually described, and in this position Dobie’s line and Hensen’s stripe are to be seen as a rule in uncontracted fibres. Between these two positions of the lens there is generally a well- marked intermediate one, which is depicted in fig. 3,6. The crests and valleys are both bright and equally so, although the slightest movement of the fine adjuster will make either one or the other the darker ; on the slopes, as it were, there are, however, narrow shaded bands, which are shown in fig. 3, b. The fibre is now quite clear and distinct, and the longitudinal fibrillation is now best made out—if it can be seen at all—and yet there is no sign of either Hensen’s or Dobie’s stripes. These being the observed appearances (and they may be verified without very much trouble), I shall calculate theoretically the appearances which a homogeneous fibre of such a shape should present when examined by transmitted light, so as to see whether our observed effects taliy with what may be theoretically calculated. Parallel rays of light pass upwards through the fibre, and in their course are altered in direction (see fig. 4). The substance of the fibre being of higher refrangibility than the fluid in which it is mounted, the thicker parts which correspond to the ridges will act like con- verging lenses, causing the rays of light to come to a focus (A A’ A”), diverging again. The thinner parts (the valleys) will, on the other hand, act as diverging lenses, causing the rays to spread out, as may be seen on reference to the diagram. Now it is evident that when the objective is arranged to focus those rays which have passed through the fibre and converge over the ridges, at that same position the rays above the valleys will be diverging (see fig. 4). This will produce a difference in the appearance, for the converging rays will give a bright band, while the position of those rays which diverge will appear darker. Alter the focus by screwing the lens up or down, and, provided the fibre can still be seen, this state of matters will be reversed; for after converging, the rays above the position of the ridges will now be diverging, while at the same time those over the valleys will be converging and will appear bright. The condition seen in fig. 3, b, which is intermediate between the low and high focussed picture of the fibre, would be obtained by shifting the lens half-way between these two positions. Hensen’s stripe is no doubt due to rays passing through the centre of the ridges suffering little refraction in their course, and thus causing a brightness. 370 Mr. J. B. Haycraft. Upon the Cause of — [Feb. 3, Dobie’s line might, of course, be the reverse of this, no rays at this point coming to the eye of the observer; but we shall speak of this more hereafter, when we shall show that there is some reason for sus- pecting at this point a distinct structure. Although it is indispensable to account theoretically for these appear- ances, yet to most persons a simple demonstration will carry more conviction than any proof deduced from the laws of optics, however well they be understood. Instead of showing “‘ what should be,” we will study ‘‘ what is.” For this purpose we will imitate as nearly as possible the figure of a muscular fibre on a small scale, and it shall be made out of a substance of uniform consistence throughout. What appearances will it present on microscopic examination? I have proceeded in the following manner:—A glass rod is heated in a spirit-lamp and plunged into a bottle of Canada balsam; it is then withdrawn, and a little drop of the balsam is allowed to fall on a glass slide, or a thread of it may be laid out on the surface of the glass. Before the drop or thread has solidified it is indented with the milled head of a fine screw, and examined with a power of from twenty to fifty diameters, when cross shadings are to be observed. ‘These are seen, moreover, to correspond with the surface impressions, and not only so, but they are reversed on altering the focus. Hensen’s stripe is generally very well seen. The most beautiful and convincing object to study in this connexion is a scale of the Lepisma. These are sold as test objects with many microscopes. They are oval in shape, transparent, and singly refractile throughout, and beautifully ribbed in their length, these ribbings or groovings being indeed so fine that a power of at least 500 diameters will be required to make out those points to be here described. You would think on looking at one of these scales that a piece of muscle was flattened out before you on the field: no rough balsam model, but a perfect illustration taken from the back of a tiny insect. The appearances it 1s needless to describe, for they are, almost to the minutest detail, those of a muscular fibre. The bright and dark stripe interchanging with every alteration of focus, Hensen’s stripe, and Debie’s line (Krause’s membrane) are all to be seen. In the case of the Lepisma scale the line of Dobie is in the centre of a bright band, which is broader than the dark band with Hensen’s stripe. This is, of course, the other way in the case of the muscular fibre. We see, therefore, that a muscular fibre presents just those appear- ances which a transparent body of uniform texture and of similar shape would possess. However conclusive these proofs may have been, it is well to collect all evidence possible to show that these markings are nothing more than optical effects, to which end a very searching experiment was suggested to me by Professor Tait. it is evident that if these cross bands are seen when parallel, or nearly 1881.] the Striation of Voluntary Muscular Tissue. onan parallel, rays of light are passing through the fibre, by using con- verging or diverging rays the appearance will be altered, and it will be possible by careful adjustment of a lens to cause a total reversal of the striping. If a fibre be carefully focussed and a strong biconcave diverging lens be placed between the stage of the microscope and the mirror, and carefully moved about with the fingers, it will be possible entirely to alter the fibre, causing a total reversal of the cross bands. On withdrawing the lens, of course the fibre resumes its normal ap- pearance. I may mention that several lenses were tried before one was found which would in at all a satisfactory manner show this phe- nomenon ; when successful the experiment is very striking. In opposition to my view is the one generally accepted, namely, that the cross stripings are produced by differences along the fibre of chemical composition, and refrangibility. Now, suppose that there were along the fibre two alternating struc- tures, A and B. Let A represent the bright stripe and B the dark stripe. If A has a higher or lower refractive index than B, it is evident that although they were immersed in any number of fluids of refrangibility varying from the lowest to the highest, yet A would always be distinguishable from B, and the striping would always be apparent. Then, again, by placing the fibres in fluids of indices near to that either of A or B, the more striking would be the contrast. If, however, the fibre were homogeneous throughout, the striping being nearly due to the form, then if the fluid and the fibre have the same refractive index all striping will disappear. On Professor Tait’s suggestion, I tried a series of fluids formed by mixing, in various pro- portions, alcohol, whose refractive index is low, with oil of cassia, which is high. In this way I have prepared specimens showing almost no cross strie, the fibre appearing uniform until after most careful examination. Dr. Klein has since shown me some muscular fibres of an insect. They were quite smooth and cylindrical, and were unstriated. In these Specimens there were, on very close examination, cross lines separated by comparatively wide intervals. It is possible that they represented Dobie’s lines.* But it may well be asked, What about the action of staining agents, such as logwood, which is stated to tint the dark stripe and Dobie’s line? Does this not show a difference of structure along the fibres ? Once having the clue it will be understood that just as the unstained * More recently my friends Messrs. Geddes and Beddard have demonstrated a very curious condition in the muscular fibres of the Echinus, which my views entirely explain. They noticed that in the same fibre some parts were cross striped, while in parts no striation was to he seen. Hearing of my explanation of the markings, they re-examined their specimens (which I have also seen), and found that when the striz were visible there, and only there, the fibre was ampullated. (See fig. 5.) 872 Mr. J. B. Haycraft. Upon the Cause of [Feb. 3, fibre will modify and change the direction of rays passing through it, so will also a stained fibre produce what are apparently modifications of the staining effect. Itis generally stated that the dark band and Dobie’s line are stained by logwood and carmine, while the bright bands remain unaffected; also that Hensen’s stripe in the centre of the dark stripe is stained only to a slight degree: whence it follows that if staining action is to be the criterion, this stripe differs in struc- ture from the dark stripe. We, however, affirm that the whole fibre is stained, and equally stained throughout. The bright band is undoubtedly stained, although it appears not of the deep blue of the dark stripe when coloured by logwood ; and this conclusion is drawn not only from an examination of my own specimens, but also from some of great beauty shown to me by Dr. Klein. Why the bright band does not appear of so dark a blue is, that the apparent shading of the latter is added to the blue tint, producing a depth of colour. The most conclusive proof of this is, that one can often reverse the colouring on readjusting the focus, and that Hensen’s stripe or the bright part of the dark stripe is only of a faint hght-blue, like that of the bright stripe. Picric acid stains muscle very readily, and colours it throughout. The fibre to the naked eye is yellow and uniformly so, but when examined by the microscope, alternating yellow and shaded yellow bands are to be observed, which reverse their position on changing the focus. With a high focus—when the crests are bright in the un- stained preparation—they are of a bright yellow, while the valleys are of a deeper yellow tint. To show the effects which a fibre of this shape can produce when transmitting monochromatic light, nothing can be more conclusive than the following experiment. A slip of coloured blue glass is held obliquely between the reflector and the stage of the microscope, so that blue rays pass through the fibre. It does not appear of a uniform tint, ~ but beautiful blue stripes are seen corresponding with the crests and valleys, and varying with alterations of focus. Ifa piece of red glass be substituted for the blue slip, red cross stripes are seen in corre- sponding places. For this experiment the fresh fibres of insects’ muscle should be examined, for, with fine mammalian muscle, the light is not so good, owing to the higher power required. This experi- ment has been introduced here with the description of stained muscle, not that it can be strictly compared with an ordinary staining process, but simply to show what an influence the fibre’s shape must have upon the tinting, supposing, as we do, that this is in reality uniform. An investigation such as this is beset with many difficulties and fallacies, and I may mention one which befel me in this stage of my work. I had stained a few muscular fibres of a rabbit with picro-carmine, 1881. ] the Striation of Voluntary Muscular Tissue. 373 and on examination, what was my surprise to find that in some of them the light stripes (valleys) were most brilliantly stained with carmine. I was long puzzled at this, when it was at last discovered that the picro-carmine had dried somewhat on the preparation, and the carmine had mechanically precipitated along the valleys, filling them up. At the end of one or two fibres this precipitation had partially peeled off, showing undoubtedly the true nature of the phe- nomenon. I have in my possession very beautiful alcoholic preparations stained with logwood. At first sight, from a study of many of the fibres, one would be led to believe that the bright stripe is wholly unstained, while the dark stripes are of a beautiful violet. A careful examination, however, reveals the fact that such fibres are broken up transversely, looking like piles of coins, a very common occurrence, especially in preparations that have been long mounted. The coins, lying close to one another, with narrow chinks between, of course revealed transverse unstained tracts, which could well be mis- taken for the bright stripe. More interest and discussion has hitherto accrued to the action of muscle on polarised light, than to the effects of staining reagents. We have seen that much difference of opinion exists: Briicke has maintained that not only is the dark stripe (ridge), as all are agreed, doubly refracting, but that the whole of the light stripe is isotropous. I myself was led to modify this, discovering that on careful focussing with a fibre not at all sheared in its length, the central part of the light stripe was undoubtedly anisotropous. This I have afterwards seen figured, as before mentioned, in Hermann’s ‘‘ Physiology,” and have introduced the diagram into fig. 2. Itis a point of some vractical difficulty to mark exactly the positions of the cross bands while turning the analyser, and thus changing the character of the field. This difficulty has been overcome completely by a suggestion of Professor Tait’s, who has helped me much in this part of the work. Very fine emery powder should be sprinkled over the preparation before covering it; for then, on examination, numberless little black specks will be seen in the field. A cross band of a fibre is selected for examination which is exactly opposite one of these little specks, then when you rotate you can definitely affirm, having the little black speck for your guide, what change has occurred. Rabbits’ muscles are very satisfactory objects for examination, as they do not cleave across at all readily. The adductor muscles of the lee should be excised, slightly stretched on a piece of wood, and placed in 50 per cent. alcohol until they split readily into fibrils. They may then be mounted in any ordinary fluid, a pinch of emery powder having been sprinkled over the preparation before covering. It is necessary to use a power of 800 or1,000 diameters in the in. 374 Mr. J. B. Haycraft. Upon the Cause of — [Feb. 3, vestigation of mammalian muscle, while in the case of the insect one of 300 diameters is quite enough. | In the living and dead muscular fibre the whole of its substance is doubly refracting. The observations of some modern observers entirely agree with my own, in that, with crossed Nicols, the crests (dark bands) and the centres of the valleys (bright stripes) appear bright and therefore refract light doubly, and that there are two dark bands on the slopes between them. (See fig. 2.) It does not follow, however, that these two dark bands represent tracts of isotropous substance. This is the point at issue. The dark lines between the valleys and ridges which appear when the Nicols are crossed have been interpreted as marking the positions of cross bands of singly refracting substance, but this is a fault of reasoning. If the fibre were smooth and cylindrical it would then follow, but the fibre is not, as we have already insisted. These bands he just on the sloped par ts of the fibre, those sections in fact which are oblique to the pass- ing rays; and the explanation is now quite easy, for the extraordinary ray passing through the fibre is naturally deflected at these parts, and does not reach the eye of the observer. Hence the body appears not to transmit them at all at these parts. It is not difficult to explain the discrepancies between Bricke’s description of the bright stripe and my own. It is essential to be very scrupulous in the selection of a fibre for examination. It must not be at ali twisted, or sheared in the slightest degree, for then the cross stripes are not at right angles to the long axis, and as their width is several times their thickness (in the length) overlapping will to some extent occur. This will certainly lead to very confusing results, and the bright centre of the bright stripe (valley) may well be overlooked. Moreover, the fibre should be slightly stretched and as small as possible. It has previously been mentioned that in many preparations the fibres split up transversely in a most regular manner, and unless the cover-glass be pressed upon, the little disks remain in position with narrow chinks between them. These chinks will be filled with the isotropous fluid used for mounting, which will lead to very anomalous appearances, and which may perhaps help to account for some of Briicke’s statements. These fallacies may be avoided by a study of the fresh fibres of insects’ muscle. Dytiscus and Hydrophilus muscle has received a large share of the attention of histologists, but that from the wasp or blue-bottle fly is quite as good. A leg should be pulled from the trunk of a blue-bottle fly and this again forcibly separated at the middle joint. A piece of muscle will project from one of the segments, which may be cut off and examined in a drop of fluid expressed from the thorax of the fly. The polariscopic effects may then be made clearly out in the still contracting fibres. I have 1881.] the Striation of Voluntary Muscular Tissue. ato tested all these points by a careful examination of insects’ fibres with thin plates of selenite and mica. This method is not so satis- factory, nor do the differences of colour seen give such trustworthy evidence as may be obtained by the crossed Nicols alone. The. Fibre during Contraction—Living insects’ muscle may be examined and the changes observed when the waves of contraction pass along the fibre, or perhaps better still, they may be fixed with osmic acid. The muscles from the leg of an insect are rapidly separated out on a slide, and a drop of weak osmic acid added which kills the fibres instantaneously, fixing them in the position that they happen to be in. On examination one generally finds fibres which in part of their course are contracted, and in other parts relaxed, when the differences in appearance may readily be studied. It may here be observed that the fibres bulge at the contracted part, so that if the surfaces be examined the focus of the microscope must be ac- commodated. The cross stripes are nearer one to another and correspond, as before, with the ridges, and valleys seen at the margin, which are much more prominent and bolder in outline. In the Contracted Fibre the Striping is practically the same as in the Stretched Condition—The contracted fibre exhibits just the same reversing of stripes on alteration of focus, and Dobie’s line and Hensen’s stripe can both be seen in the same positions’ as in the un- contracted muscle, provided the fibre is suitably placed for examina- tion and not sheared in its length. We must entirely deny the common statement, first introduced, we believe, by Merkel and Engelmann, that in the contracted state the bright band becomes the darker. If good specimens of insects’ muscle be examined, which have been treated with osmic acid, and if the fibre be not sheared, the valley is always bright in the ordinary or deeper focus. I have verified this point in very many cases. Passing along a fibre from the relaxed end to a part where the contraction is fullest, the appearances vary in degree, but not in kind. The main features are in both cases the same, but the stripes are now narrower, and often it is not so easy to see Dobie’s and Hensen’s stripes. This follows from the statement of Engelmann, viz., that “the bright stripes become darker than the dim; ”’ for he himself notices that at one point, or phase, in the contraction, no striping is to be made out. We agree with Ranvier that this is not true, indeed it would be impossible for a muscular fibre with its con- ficuration not to be marked across its length. This subject will call up to the mind of every working histologist, appearances which he must have met with in other fields of research. Many tissues naturally, or after clumsy manipulation, present am- pullations which always co-exist with cross strie. The fibres of the crystalline lens are wavy in outline, and when many of them are VOL. XXXI. | 2 O76 Mr. J. B. Haycraft. Upon the Cause of — [Feb.’3, bound together and seen on edge with the wavy outline towards the eye of the observer, cross bands are seen which in chance prepara- tions (especially those of the frog’s lens) simulate muscle in a wonder- ful manner. Ordinary non-striped muscle which may be so well seen in the frog’s bladder is often faintly ampullated especially, perhaps, in chloride of gold preparations. Cross stripes may also here be seen. The fibres of Tomes, when a section of softened tooth is teazed, are pulled out of the dentinal tubules, and, being of a soft and somewhat elastic nature, on breaking they become often very beautifully am- pullated, and it would be impossible to distinguish them from muscular fibrille. In the class of practical histology, on more than one occasion, students have asked me the meaning of beautiful cross shadings seen on nerve fibres; a slight ampullation which fully accounted for it, was always found. Many more of such instances could be recalled in the experience of every one; it is needless to enumerate further. In the winter of 1879-80, while examining fibres of the muscles of a newly-born child, a very curious discovery was made. A nucleus belonging to the sarcolemma was seen beautifully striped. It was not in close apposition to the fibre, a very narrow chink intervening. On focussing with great care, it was seen that the cross bands upon it corresponded with those of the adjoining fibre, a dark one, however, for a light one, and vice versd. (Fig. 6.) Now, the curious point was that the nucleus had evidently been impressed by the fibre, moulded upon it, as it were, and on being pulled apart had presented a perfect cast of the surface. One would hardly believe in sarcous elements here. Last summer (1880) my friend Mr. Priestley communicated to me a similar and independent observation of his own, as a contribution towards the maintenance of my views upon the formation of the stripes. The position that we have reached is this : a muscular fibre presents such cross markings, varying with shifting the lens up or down, as a filament cf homogeneous structure and similar shape. I have shown this experimentally, and have illustrated it by simple experiments, which it is in the power of anyone to test. This being the case, I have searched to find if there be reason to assert any want of uni- formity along the fibre, using various methods of staining. This I have failed to do, and have shown that the views commonly held are to be explained simply by the shapes of the fibres. As to the action of muscle on polarised light, I saw reason to dissent from the views of Briicke, and subsequently found my own in accordance with those of other recent observers. I differ from them in the explanation I offer of the two dark bands seen with crossed Nicols, for here, again, the shape of the fibre explains their presence without looking for any special structure. 1881.] the Striation of Voluntary Muscular Tissue. 377 So far we are led to consider the fibre as made up of many ampul- lated fibrils, packed side by side, forming an ampullated fibre, these fibrils being uniform throughout, and joined together by some cement- ing material, the nature of which we will not surmise. The only point which would suggest a definite structure along the fibril is the attach- ment of the sarcolemma in insects’ muscle to Dobie’s lines. There is no doubt that this membrane dips down and seems prolonged into Dobie’s lines in a most beautiful and regular manner. The signifi- cance of this is very obscure, and is quite beyond me. There are many possibilities. It may be, although there is no proof of it, that a membrane exists here continuous with the sarcolemma; it may be that there is nothing but some cementing substance more soluble in alcohol than the sarcous matter: it may be that there is a little minor crest at this point to which the sarcolemma is attached. This little crest I have certainly seen in some fibres, and it has already been figured by more than one writer, yet in other fibres, the outlines of which are wonderfully distinct, no trace of it is to be made out. The fibres can hardly be said to break across in the line of Dobie, all that can definitely be affirmed is that they cleave in the thinnest part, or the light stripe. The investigation of this point is one of great difficulty, owing to the haze around the broken points, and I can never make up my mind to any definite statement. This transverse cleavage is not of course a point of very much weight, as the fibre would naturally tend to split across in or near Dobie’s lines, as here it is thinnest. The striping of muscle can be easily explained, as shown before, which leads me to my final statement. A fibrilis structureless through- out its entire leneth, except that, perhaps, there may be membranes, or lines of fission, or layers of cement at the positions of the lines of Dobie; this we leave an open question. In using the word “ struc- tureless,” I must not be misunderstood ; structureless membranes and tissues are fast losing their place in histology, and once simple proto- plasm is now most complex. What I infer is that the stripes do not mark the positions of alternating layers of different structure, the presence of which are ordinarily maintained. The complicated “ Muskelkistchen ” of the Germans do not exist. The muscular tissue of the heart presents many peculiarities which it is needless here to enumerate, for the cross striping alone concerns us. All those cross bands which have been described in ordinary voluntary muscle may here also be seen, and they are placed in the same rela- tions with the turned surface of the fibre. The dark stripe correspond- ing to the crests, or ridges, the light bands to the depressions between them. (Fig. 7.) Dobie’s lines may be made out with great ease, and as there is no sarcolemma here, they may be accounted for also purely from the shape of the fibres. I have often thought that Dobie’s lines marked the positions of tiny ridges in the valleys, but this is a 252 378 Mr. J. B. Haycraft. | Upon the Cause of —_ [Feb. 3, point more difficult to decide perhaps than in the case of the skeletal muscles. Transverse cleavage takes place here also in the thinner part of the fibre, namely, in the bright stripe, but whether or not exactly in Dobie’s line I have not yet definitely made out. A curious appearance often presented by insects’ muscle, and some- times also by that of the mammalia, has been described and figured by Mr. Schiifer. A paper descriptive of these he communicated to the Royal Society of London (1873), which came out later on in the “Transactions” of this Society, and his observations are published also in the eighth edition of Quain’s “ Anatomy.” These have been almost entirely overlooked by French and German physiologists, yet in many English laboratories his observations have been verified, and his conclusions taught. They are well illustrated in a representation of the muscular fibre of a Dytiscus, which may be seen in Quain’s “ Anatomy.” The dark stripes are traversed longitudinally by dark rods, which end at both extremities in little knobs. These knobs he in the borderland between the bright and dark stripes. The only point which I would add to his figure is this, that the knobs are joined across the clear stripes or valleys by lines, just as they are so joined across the dark stripes, although the lens must be depressed ever so little to make this out. These lines are, in fact, nothing more or less than the longitudinal strie described many years ago as lying between the fibrillee of which the fibre is composed, these little knobs lying in their course. This can, perhaps, most conclusively be made out in the following way. Allow a piece of insect’s muscle to remain in a drop of water for some hours (which will vary with the temperature) until it has partially putrefied. Then cover and examine, when many of the fibres will have separated towards their ends into fibrille. One can then dis- tinctly trace the chinks between the separated fibrille as being con- tinuous with the striz, on which the knobs are still seen, in the centre of the fibre. I think that the following is a feasible explanation of these knob-like enlargements of the cementing substance seen as longitudinal striz. These knobs occur, as will be beautifully seen on referring to the woodcut in Quain, on the slopes between the valleys and the ridges. The cementing substance dips down here with the ~ fibre itself, and if there be the slightest lateral obliquity it will appear larger. The cementing matter is seen on edge, and differing as it does from the muscle-substance in refrangibility, a distortion occurs, giving rise not to a dark line as on the surface, but to a dark knob. This is, in fact, but an optical delusion, for the striz are quite uniform, and were the fibre cylindrical would appear so. This may be proved by the fact that very often if the rays of light from the reflector are oblique, but one set of dots appears, which shift over to the other side on twisting the mirror. By shifting the preparation es RR 1881. ] the Striation of Voluntary Muscular Tissue. aa about, or by twisting the tube of the microscope obliquely, the dots disappear from one part of the fibre to appear in another, showing that it is but an optical effect, and that no structure here exists. Before concluding I must gratefully acknowledge much help and sympathy which I have received in this investigation. To Professor Tait I have gone when in any difficulty, for an observer in a case such as this must have the aid of an experienced physicist, otherwise grievous error is but courted. ‘To him, as has been seen in the text, I owe many suggestions, and he has kindly entirely looked over my paper. Dr. Klein has shown me great kind- ness in carefully examining my preparations from the histological point of view, and as has before been mentioned, in showing me pre- parations to corroborate my views. My thanks are also due to my friend Mr. John Priestley, for many hints, especially concerning the literature of the subject. 7 DESCRIPTION OF PLATE 5. Figure 1. This represents a muscular fibre viewed with a very high power. The borders are wavy and the cross stripes correspond with these inequalities. (D) marks the positions of Dobie’s dark stripes placed in the centres of the depression seen at the border. (H) represents Hensen’s stripes, or Dobie’s light stripes, placed on the summit of the ridges, in the centre of the dark band. Figure 2 shows the appearance of the fibre with crossed Nicols. The shaded parts are seen on the slopes between the ridges and depressions. They are explained fully in the text. Figure 3. A fibre is represented as seen with three positions of the lens. In (qa) the lens is elevated and the depressions appear dark. Im (c) the lens is fully depressed when the stripes are reversed, the depressions being now light with Dobie’s dark stripe in the centre of them, and the crests dark but with Dobie’s light stripe in the midst. In (0) an inter- mediate stage is seen. Figure 4. This shows the passage of rays of light through the fibre. The convex parts converge the rays to focus A’, A”, A”, after which they diverge. The lens shifted up or down (vertically) over the ridges or depressions, will focus on the retina alternately converging and diverging rays. Figure 5. Muscular fibres of Echinus, described by Messrs. Geddes and Beddard. Figure 6 represents a nucleus seen by me, which impressed on the muscle, is moulded to the same shape and appears to be cross striped. Figure 7 shows the striping of the muscular tissue of the heart. 380 Prof. Owen. On the Gigantic Land-lizard. [Feb. 3, II. “Description of some Remains of the Gigantic Land-lizard (Megalania prisca, OWEN) from Australia. Part IIL” By Professor OWEN, C.B., F.R.S., &c. Received January 20, 1881. (Abstract. ) In this communication the author describes additional parts of the Megalania, reconstructed from fossils exhumed by Mr. George Fred. Bennett, at the same locality as the subjects of Part II, and sub- sequently transmitted. They were found about thirty feet distant from the spot where the cranial fossils were imbedded, and are deemed by their discoverer to be parts of the skeleton of the same individual. The recognisable restorations constitute the termination and a detached annular segment of the hony sheath, with one inclosed vertebra, of the tail. The average thickness of the sheath’s sub- stance is one inch; the coalesced portion includes three segments ; and, save the last, these with the antecedent detached segment sup- port osseous conical processes, in structure resembling the horn-cores of the cranium, but of larger dimensions. Hach segment supports two pairs of such solid cones or cores. The transverse diameter of the antepenultimate segment taken across the tips of a pair of cores is eleven inches; the same diameter of the area of such annular sheath is five inches; the vertical diameter of the exterior of the sheath is five inches and a-half. These dimensions support Mr. Bennett’s conclusion as to their relation to the skull; and, supposing the lizard’s body originally entombed not to have undergone a dis- location affecting the two extremities uow brought to light, their relative distance agrees with the length of the animal, estimated from proportions of previously described vertebree. Detailed descriptions, with figures, of the parts of the horn-bearing tail-armour are given, and comparisons are subsequently pursued in examples of recent and fossil Reptilia and Mammalia, provided with similar caudal armature. Illustrations of these and of the parts of Megalania compared accompany the paper. 1881.] Bimodular Method of Computing Logarithms. 381 ® Ill. “On a Method of Destroying the Effects of slight Errors of Adjustment in Experiments of Changes of Refrangibility due to Relative Motions in the Line of Sight.” By E. J. Stone, F.R.S., Director of the Radcliffe Observatory, Oxford. Received January 17, 1881. Let arrangements be made for the reversion of the prisms without any disturbance of the other optical arrangements, including, of course, the position of the cylindrical lens, if one be used. Any slight errors of adjustment which prevent the light from the star and the comparison light from falling upon the train of prisms under the same optical circumstances, so far as mere direction is concerned, will have opposite effects in the reversed positions of the prisms; but the separation of the emergent lights due to relative motion will remain unchanged by the reversal of the positions of the prisms. If, therefore, the apparent change of refrangibility due to relative motion remains unchanged by the reversion of the prisms, all doubts about the effects of errors of adjustment will be removed. But if the results in the reversed positions of the prisms sensibly differ, then the existing errors of adjustment must be removed, or their effects allowed for by taking a mean of the results in reversed positions, before any reliance can be fairly placed upon the determination of relative motions in the line of sight. A reversible spectroscope was arranged by me, and made by Mr. Simms, some years ago, but I have never since had an equatoreal, with a good driving clock, under my control with which the experi- ment indicated could be properly tried. With the direct prisms now in use, the required reversion can be easily arranged. Iam not hkely, for some time, to have the use of a good equatoreal, and I, therefore, publish the plan with the hope that some one more fortunately situated may give it a fair trial. The experiment is a crucial one, and, in my opinion, should be tried. IV. “Onan Improved Bimodular Method of computing Natural and ‘Tabular Logarithms and Anti-Logarithms to Twelve or Sixteen Places, with very brief Tables.” By ALEXANDER J. Huuis, B.A., F.R.S., F.S.A. Received January 17, 1881. Section [.—Narure or tHe BrmopuLtaAR MeEtHop AND ITs IMPROVEMENT. The Bimodulus is a constant, which is exactly double of the modulus of any system of logarithms. The Bimodular Method is derived from 882 Mr. A.J. Ellis. Lmproved Bimodular Method of [Feb. 3, the familiar proposition that, when the difference of two numbers is small, the difference of their logarithms is nearly equal to the bimodulus multiplied by the difference and divided by the sum of the numbers themselves. The improvement here for the first time effected, consists in prefixing a brief preparation, which makes the method uni- versally applicable, and subjoining an easy correction depending on the transformation of a well-known series proceeding by the odd powers of the difference divided by the sum of two numbers, whereby the number of places obtained is greatly increased. This method is here applied for finding the natural and tabular logarithms of any number to twelve places of figures by means of a table of two pages for each kind of logarithm, and to sixteen places by help of a seven- place table of tabular or Briggs’s logarithms. An extremely simple rule, which, so far as I know, was never before imagined, enables us to pass from the logarithm to the number, that is, to find anti- logarithms from the same tables. Although the method is applicable to any system of logarithms, and was actually first applied by me to the direct calculation of musical logarithms to the bases 2 (octave), 2/2 (equal semitone), and 81+80 (comma), and appropriate tables have been constructed, I confine myself for brevity to natural and tabular logarithms. The tables are constructed from existing mate- rials, but the method is capable of constructing them independently. Srction I].—PRINcIPLES OF THE BimopULAR METHOD AND ITS IMPROVEMENT. Fundamental Relations—Let n and d be any whole numbers of which d is the smaller, and let p=d-n, a proper fraction. Let nat. log 1 +p)=y, and log (1p) —Ma ee where M is the modulus, and hence 2M the nono dinice to any un- specified system of logarithms marked by log. Let d p SS ee ao =wv, 2M =Mr=z : 5 : 5 D . my OR ae ie n In future » and n+d will often be called “ the numbers,”’ 7 “the tabular number,” d “the difference,’ 2Md ‘the dividend,’ 2n+d “the sum” or “ divisor,” and 2Md+(2n+d) “the quotient.” Now it is familiarly known that YP — Sp? 3D — ap ae) a =2(¢tig+igot...). . . 2) eee Putting in (4) the values of q in terms of w and z from (2) we have 1881.] computing Natural and Tabular Logarithms, Sc. 383 Yee + ye tale +... Sete. 2. BO), Bh ee Zz? M gl My=2z+ 45. apt Be yet FSS ‘ayet Soe SH IG (() a And putting for w and z their values from (2) we find 2p=(2+p)x, 2Mp=(2+>p)z, whence i alates ME (Os —x —Z And by expanding the first of these equations (7) a=p—tp?+ip?—gptt+... Poet stte (S)). Subtracting (8) from (3), and Go aes by M to find the Me of (6), we have My—z=Mce=M(,y a Oran. Be spac! a) 2 age (9), a converging series of which the limits are the first term and the first two terms. Preparation.—To insure p being small in all cases, I have invented the rule of preparation, founded on the fact that if N be the number whose logarithm is sought, and a and 6b any two numbers of which the logarithms are known, such that Na+b=n-+d, where n is the next less number to Na~b in the table, and d, the difference, is less than the difference between two numbers in the table, then log N=log (n+d)+log b—log a. In Tables I and II the difference between two consecutive numbers is ‘001, and as there are 100 entries, all the numbers lie between 1 and 1'1; so that if Na~bd is less than 1-1, the required reduction is effected. 3 Preparation is accomplished in two lines of simple multiplication and division, as follows :— The given number N is divided or multiplied by such a power of 10 as will leave the quotient or product as a decimal fraction between 1 and 10. This is effected by simply shifting the decimal point. Tf the first decimal place is Jess than 3 times the integer (which is always the case when the integer exceeds 3), divide by the integer and divide the quotient by 1:1 or 1:2. The result is less than 1:1. If the first decimal place is more than twice the integer, then it is always possible, generally in several ways, to find an integer between 1 and 10 which, used as a multiplier, will give a product of which the integer is less than 13, and the first decimal place less than the integer. The following rule embraces every case :—Multiply any of the numbers 1:30 to 1340 by 4; 1:340 to 1:80 by 7; 1:80 to 1:960 by 5; 1:960 to 199 by 6; 2°50 to 2:99 by 4; 3°80 to 3:99 by 3. Then dividing this product by the integer the quotient is less than 1°1. This preparation is very convenient also for starting Weddle’s and 384 Mr. A.J. Ellis. Improved Bimodular Method of [Feb 3, Hearn’s processes given by Mr. Peter Gray in the introduction to his Tables for twelve-place logarithms, 1865 (first published in 1845), and isalso very much simpler than that proposed by Mons. Thoman in his “Tables de logarithmes 4 27 décimales,” 1867. Interpolation—The finding of log N is thus made dependent on finding log (n+d), where n is a tabular number and d is less than ‘001. We then find 2Md+(2n+d), which gives the ‘“ uncorrected ” logarithm of n+d, or the “quotient” w or z The multiplication 2M xd is effected by the multiples of the bimodulus given in the tables, when M is not 1, the unit place of each multiple of 2M being placed immediately below the determining figure of d, care being taken to preserve as many places as are necessary for the final result. The division is a single contracted division. © The resulting z or z has to be “‘corrected’”’ by the equations (5) and (6),as shown in Section III. Completion.—Having found log (n+d), we add the logarithm of the power of 10 by which we first divided, and the logarithm of any other divisor, and the arithmetical complement of the logarithm of the power of 10 or any other multiplier. All these logarithms are given in the table. The result is the complete log N to the number of decimal places for which the table is adapted. Anti-Logarithms.—A logarithm being given we have to reduce it to the logarithm of a number between 1 and 1‘l. This is most con- veniently done by subtracting from it (or adding to it) the logarithm of the largest power of 10, which will make the result lie between 0 and log 10, and afterwards subtracting the next least logarithm of an integer between | and 10, and then the next least logarithm of a number between 1:1 and 2. The logarithms of all these numbers are given in the table. The result will be the logarithm of a number less than 1:1. We then subtract the next less logarithm in the table of interpolation, and obtain the equivalent to the corrected quotient «+c or z+ Me of (5) and (6). We find the correction in the same way as for the quotient, and subtract it, thus obtaining # or z. Then we divide the bimodulus increased by this a or z, by the bimodulus decreased by this @ or z, as in (7), and thus find 1+, which is the number correspond- ing to the “quotient” in the direct method. For ‘‘ completion” this has to be multiplied by the numbers corresponding to all the logarithms subtracted in the preparation. Section III.—CatcunatTIon OF THE BIMODULAR CORRECTIONS. The principal peculiarity of this improved bimodular method con- sists in the calculation of the corrections and the determination of the number of places which can be trusted in any case, as assigned in the tables. The repetition of any digit m times within the same number will 1881.; computing Natural and Tabular Logarithms, &c. 389 be represented by suffixing m to the right of that digit. Thus, -0,,1 is a decimal fraction beginning with m zeroes and followed by 1, and nat. log 1:0,1=°0,9,50,3,083,53, to forty-eight places. Other writers have used 0” in this sense, but it is not applicable to other digits, and conflicts with the usual notation of powers, thus 230? looks like (280)?=12,167,000, in place of 23,000=230.. Write equations (5) and (6) thus— matloga( lp ia C—@- CutiCocte. =). es) ce CLO): Teo). Moye (MWS 9)) ore acing eee!) oe 6 a (LIL). where it =e 0oas!-y., Co 0—e « Ola)! 2a Gi2ye tal. logc,—o tab. log a#---920 S188 —2 . . . . (Cay tab. log ¢;=0 tab. log#+-096 9100—2 . . . . (14), tabs lova2— 2 tab, log ea aoo (270 |. 71). . 1 Gor h=2x ‘441 824 842 5389 87, t=22x°351 376 544 673 68. (16), tab. loz =3 tab: log z+-640 2501—1 . . . . (4%); tab. log 4,=5 tab. log z+°545 7728—1 . . . . (18), tab locz— a babslog gt 1LS, 2500) . b=. eGlgip By means of these equations the corrections can be calculated from the “quotient” (that is, the approximate values of # and z) either with or without existing tables of logarithms, or the quotient 2 or z may be calculated to which a particular value of the first correction is due. From these has been calculated the following table of the critical values of the first and second corrections, upon which the whole practical use of the corrections depends. The quotients were first taken to proceed from ‘0,1 to ‘On9 by steps of ‘0,1. Then the values of the quotients were determined, which reduced either of the two first corrections to ‘0,1, n being variable, from which point the suffix of 0, or the number of initial zeroes, changed, giving critical values of the corrections. Such quotients were then inserted in numerical order. The approximate numbers were obtained from the quotients on the supposition that p was small enough to make nat. log (1+ ) =p, and tab. log (1+p)=Mp, to three places of significant figures. The suffix of 0 in the first correction, diminished by 1, shows the number of places which are unaffected by that correction, that is, the number of places in the uncorrected quotient which may be trusted without corrections. The undiminished suffix shows a number of places which cannot be wrong by more than one unit in defect in the L06 SIT (00) a0 06% G66 E1Z OLT oott*™%0. Zpestso, 098 oors 40. PS9 989 oIL oot? t™40. LET ooT"t™%0. eager ag. Improved Bimodular Method of [Feb. 3, 2) FO On[VA Mr. A. J. Ellis. O86 G6& 966 806 6ST 0ot*0- 56 agg B69 t9e*™0, E82 GOL 6IT oortt“s0. EGE 6ZE ooT?*"*0. LZ8 epyer™to. "M7 Jo on[VA 006 602 008 98T SLL 621 O04 €9L 609 IVT 009 66T OOG HEE 169 SIT pev"0- oor “0. T OOP G26 Ors §T4 O0€ €69 68G 699 006 GOV S6T OSD T&T 60E cerca PSs OOLO: T&s"0- T *quotjonb “Toquinu. qOusy oyoutrxordd vy "SULTJLIVGOT AVG, “TT = 8sZ 60F O1Z oot? to. G16 166 G9 86L ooTs="*0. POS ool ts0. 984 OOF oor t"%0. 691 gel rM. "F9 JO ONTVA L409 96V G86 €8T OST POT COR. 0: Eg 09°F CS OIL oor? ™*0. 999 062 ooTst™*0. egg’ 80. ‘Td JO On[BA 006 008 O04 VO9 009 OOS S6V OOV I8é O00 OVS 666 00% SSL 90T OOL“O- ‘quotyonb {OVX AT “STUYJLIVSOT [VINJVNT “T ‘SUOTPNOAIOL) OY} JO SON[VA [VOTILIC) 94 JO o]qQuy, 18 OO OVE 666 00% SST 90T 0010. T “ToqumMnu eyeurxoaddy 1881.] computeng Natural and Tabular Logarithms, &c. 387 last place. The suffix of 0 in the second correction, diminished by 1, shows how many places of the quotient, after applying the first correction, are left unaffected by the second correction, that is, how many places can be trusted on applying the first correction only. For natural logarithms it will be seen that this never gives less than 5m-+1 places, that is, 2m-+1 places in addition to those determined without correction. Thus in Table I, where m is never less than 3, we can always obtain sixteen places. For tabular logarithms, as in Table II, we must first observe a critical value in the numbers them- selves. In that table the number 1+p, whose logarithm is finally sought, must be less than 1:001. Hence, while in the upper part of the preceding table of critical values, m will always be 3 or more, in the lower part, m—1 will always be 3 or more, so that m will always be 4 or more. As far then as the quotient ‘0,434, the first correction gives only 5.3+1=16 places, and this is the largest quotient that can commence with ‘0,. If the significant figures are greater than 454, then m will be 4, and up to the quotient ‘0,778 we can trust 5 .4=20 places, and beyond it we can even trust 19 places. Observe that ‘0,9 at the bottom of this table is followed by ‘031 at the top (II, second column), for which, also, the second corrections leave o.3+4=19 places unaffected. But in determining the full number of places of the first correction from the uncorrected quotient by equations (12) and (18), we are, of course, obliged to take so many significant places, that on cubing the result and multiplying by the proper coefficient, no error affecting the full number of places should be committed. The number of places required for this purpose is so large that'if we calculated the result directly, the present method of correction would be illusory. Hence it is necessary to use common seven-place logarithmic tables which can be trusted to six places. Consequently, we can use only six significant places in the quotient for finding the correction, and we thus introduce an error not exceeding half a unit in the last place in excess or defect. On estimating the limiting effect of this error, I find practically that on using six significant places of the uncor- rected quotient to determine the first correction, we may trust all six places of the correction found. The total number of places that can be trusted, when this error is allowed for, depends on the quotient. Let 7 be the significant places of the quotient converted into a decimal fraction with one unit place. Then the real quotient is -0,,1 x7, but on taking only six significant places, we use as a quotient ‘0,1 xr+ ‘O,,+¢1 X 5, and the error thus made in the correction may be taken as the term involving 7? in the cube of this number divided by 12M?, that is, as “0,431 X 15r?+-12M?. Then, putting 157?+12M?=10 and 100, and finding the corresponding values of 7, we obtain the critical values of the quotient where the suffix of 0 in the error of the 388 Mr. A.J. Ellis. Improved Bimodular Method of [Feb. 3, Bimodular Table I.—Natural Logarithms. 1. Table for Interpolation. No. Natural Logarithm. No. Natural Logarithm. 1-000 “000 000 000 000 000 000 | 1:050 "048 790 164 169 432 003 IL ‘000 999 500 333 083 533 51 "049 742 091 894 814 074 2 ‘001 998 002 662 673 056 52 050 693 114 315 518 118 3 ‘002 995 508 979 798 478 53 "051 643 233 151 838 450 4 "003 992 021 269 537 453 54 ‘052 592 450 119 170 584 1 005 ‘004 987 541 511 039 074 | 1°058 053 540 766 928 029 818 6 7005 982 071 677 547 464 56 054 488 185 284 069 731 di ‘006 975 613 736 425 242 5) 055 434 706 888 100 582 8 ‘007 968 169 649 176 874 58 ‘056 380 333 436 107 639 9 ‘008 959 741 371 471 904. 59 ‘057 335 066 619 269 407 1:010 ‘009 950 330 853 168 083 | 1°060 058 268 908 123 975 776 il ‘010 939 940 038 334 364 61 "059 211 859 631 846 083 12 ‘011 928 570 865 273 802 62 060 153 922 819 747 O91 13 "012 916 225 266 546 328 63 ‘061 095 099 359 810 876 14 "013 902 905 168 991 421 64 "062 035 390 919 452 641 1-015 014 888 612 493 750 655 | 1°065 ‘062 974 799 161 388 435 16 | -015 873 349 156 290 149 66 ‘063 913 325 743 652 797 We "016 857 117 066 422 899 67 ‘064 850 972 319 616 314 18 ‘017 839 918 128 331 000 68 ‘065 787 740 588 003 097 19 "018 821 754 240 587 761 69 ‘066 723 632 042 908 173 1 +020 "019 802 627 296 179 713 | 1°070 ‘067 658 648 473 814 805 21 "020 782 539 182 528 504 ae ‘068 592 791 465 611 716 22 "021 761 491 781 512 692 72 ‘069 526 062 648 610 245 23 "022 739 486 969 489 429 73 ‘070 458 463 648 561 419 24 "023 716 526 617 316 042 74 ‘071 3889 996 086 672 945 1025 ‘024 692 612 590 371 501 | 1°075 ‘072 320 661 579 626 121 26 | °025 667 746 748 577 792 76 "073 250 461 739 592 673 27 026 641 930 946 421 178 77 ‘074 179 398 174 251 512 28 ‘027 615 167 032 973 365 78 ‘075 107 472 486 805 412 29 ‘028 587 456 851 912 555 79 076 034 686 275 997 608 1-030 "029 558 802 241 544 403 | 1°080 ‘076 961 041 136 128 325 31 030 529 205 034 822 873 81 °077 886 538 657 071 225 32 ‘031 498 667 059 370 991 82 "078 811 180 424 289 778 33 ‘032 467 190 137 501 495 83 ‘079 734 968 018 853 559 34 ‘033 434 776 086 237 388 84 ‘080 657 903 017 454 467 1-035 "034 401 426 717 332 396 1:085 7081 579 986 992 422 874 36 035 367 143 837 291 316 86 "082 501 221 511 743 696 37 "036 331 929 247 390 277 87 "083 421 608 189 072 391 38 037 295 784 743 696 896 88 | °084 341 148 433 750 885 39 "038 258 712 117 090 341 89 085 259 843 950 823 419 1:040 039 220 718 153 281 296 } 1°090 "086 177 696 241 052 332 Al "040 181 789 632 831 832 Jil 087 094 706 850 933 767 42 "041 141 943 331 175 177 92 7088 010 877 322 713 299 43 "042 101 176 018 635 394 93 "088 926 209 194 401 509 44 043 059 489 460 446 977 94 ‘089 840 703 999 789 463 1 °045 044 016 885 416 774 327 | 1-095 "090 754 363 268 464 143 46 044 973 365 642 731 158 96 "091 667 188 525 823 792 47 "045 928 931 888 399 803 97 "092 579 181 293 093 194 48 "046 883 585 898 850 420 98 "093 490 343 087 338: 889 49 ‘047 837 329 414 160 128 99 094 860 675 421 484 311 i 1881.] computing Natural and Tabular Logarithms, &e. 389 2. For Preparation. 5. For Full Corrections, Additive. No Natural Logarithm. ; eee Take six significant figures of the quotient, and mers arcs Tae use six significant figures of the cor. from this 1-1 j 0-095 310 179 804 324 869 | formula— D2 0°182 321 556 793 954 626 1°3 0°262 364 264 467 491 052 tab. log cor.=3 tab. log quotient+ °920 8188—2. 1-4 | 0°336 472 236 62] 212 931 Trust all the places thus corrected, that is— 1°5 0°405 465 108 108 164 382 1°6 0°470 003 629 245 735 554 Ibe 0°530 628 251 062 170 396 | For Difference, F 3 1-8 | 0-587 786 664 902 119 008 | or Quotient, Trust in result places, 1°9 0:°641 853 886 172 394 776 ; x 0,100 14 And one place more in each 2 io 0 "693 147 180 559 945 309 "0,894 15 case with a probable error in it 350 PUB OZ 2885668) .109 1691 °0,,284 16 of one unit in defect 4°0 1°386 294 361 119 890 619 “0.100 17 ; 5:0 1°609 437 912 434 100 875 “0 894 18 6:0 1°791 759 469 228 055 001 2 7:0 1:945 910 149 055 313 305 8°0 2:°079 441 541 679 835 928 P 3 F 9-0 2°197 224 577 336 219 383 For intermediate quotients trust the number of 10:0 2-302 585 092 994 045 684 places opposite the next greater. 11°0 2°397 895 272 798 370 544 12°0 | 2°484 906 649 788 000 310 3. Multiples of nat. log 10. 6. For Short Corrections, Additive, giving twelve places. NGuOE Work to thirteen places. Possible error on ‘‘ com- 2 Natural Logarithm. pletion” one unit in the twelfth place. For interme- mult 8 5 : | diate quotients use the correction opposite the next —_— ————] less. 1 2°302 585 092 994 045 684 2 4°605 170 185 988 O91 368 3 6°907 755 278 982 137 052 4 9-210 ae 371 916 182 736 Quotnt.| Cor Quotnt.} Cor. } Quotnt.| Cor 5 11°512 925 464 970 228 420 *0,000 | °0,,00 | :0,707 0,30 | °0,894 | °0,,60 6 13°815 510 557 964 274 104 182 1 715 899 61 7 16°118 095 650 958 319 788 262 2 723 32 904 62 8 18°420 680 743 $52 365 472 311 3 731 33 909 63 348 i 738 34 913 64 9 20°723 265 836 946 411 156 10 23 °025 850 929 940 456 840 0,378 0,,05 "0,745 0,085 0,918 0,,65 il 25°328 486 022 934 502 524 404 6 752 923 12 27°631 021 115 928 548 208 427 7 759 37 928 67 : 448 8 766 38 932 68 13 29°933 606 208 922 593 892 467 9 773 39 937 69 14 32°236 191 301 916 639 576 15 | 34°538 776 394 910 685 260 0,485 | °0,,10 } °0,780 | -0,,40 | -0,941 | -0,,70 16 36°841 361 487 904 730 944 501 1 786 4] 946 517 12 792 42 950 72 531 13 798 43 952 73 4, For no Corrections. 545 14 805 44 959 74 Age Bt "0,558 | °0,,15 | -0,811 | °0,,45 | -0,963 | °0,,75 or Ditterence . , 571 16 817 46 968 76 or Quotient, >! Trust places, uncorrected, 583 7 923 47 972 = iS pans 594 18 829 48 976 7 0,100 9 And one place 606 19 835 49 980 79 0,493 10 more in each case 0,229 11 with a probable | "03616 | °0,020 | °0,841 | °0,,50 | -0,984 | °0,,80 “0,106 12 error in it of one 627 ae a 1 289 81 0,493 13 unit in defect. 637 22 852 52 993 82 “0,229 14 646 23 857 53 997 83 0,106 15 656 24 863 54 0,193 16 i "0,665 | ‘0,525 | °0,868 | °0,,55 674 26 873 56 For intermediate quotients trust the ae a ea of number of places opposite the next 699 29 889 59 gr2ater in the above table. 3890 Mr. A. J. Ellis. Improved Bimodular Method of [Feb. 3, Bimodular Table I].—Tabular Logarithms. 1. Table for Interpolation. No. Tabular Logarithm. No. Tabular Logarithm. 1-000 | *0C0 000 000 000 000 000 | 1-050 021 189 299 069 938 073 i "000 434 077 479 318 641 51 "021 602 716 028 242 220 2 "000 867 721 531 226 912 52 "022 015 739 817 720 259 3 ‘001 300 933 020 418 119 53 "022 428 371 185 486 518 4 | 001 733 712 809 000 530 54 | *022 840 610 876 527 803 1-005 "002 166 061 756 507 676 | 1:°055 023 252 459 633 711 470 6 | :002 597 980 719 908 592 56 023 663 918 197 793 454 7 "003 029 470 553 618 007 57 ‘024 074 987 307 426 268 8 | °003 460 532 109 506 486 58 | *024 485 667 699 166 953 9 | :003 891 166 236 910 522 59 024 895 960 107 485 003 1:010 | -004 321 373 782 642 574 |1-°060 | :025 305 865 264 770 241 11 "004 751 155 591 001 063 61 "025 715 383 901 340 666 12 | ‘005 180 512 503 780 310 62 | °026 124 516 745 450 260 13 005 609 445 360 280 428 63 "026 533 264 523 296 757 14 | :006 037 954 997 317 171 64 | 026 941 627 959 029 378 -1°015 | -006 466 042 249 231 723. | 1°065 027 349 607 774 756 528 16 006 893 707 947 900 450 66 027 757 204 690 553 459 17 007 320 952 922 744 597 67 "028 164 419 424 469 893 18 | -007 747 778 000 739 942 68 | -028 571 252 692 537 612 19 008 174 184 006 426 395 69 | °028 977 705 208 778 017 1-020 008 600 171 761 917 561 4} 1°079 | -029 383 777 685 209 641 21 009 025 742 086 910 247 val ‘029 789 470 831 855 634 22 009 450 895 798 693 927 72 "030 194 785 356 751 218 23 009 875 633 712 160 158 73 030 599 721 965 951 084 24: ‘O10 299 956 639 811 952 74 ‘031 004 281 363 536 802 1-025 010 723 865 391 773 104 | 1-075 031 408 464 251 624 136 26 ‘O11 147 360 775 797 468 76 031 812 271 330 370 371 27 "O11 570 443 597 278 197 77 "032 215 703 297 981 585 28 "O11 993 114 659 256 928 78 032 618 760 850 719 897 29 012 415 374 762 432 929 79 "033 021 444 682 910 673 1-080 | -012 837 224 705 172 205 | 1°080 | -033 423 755 486 949 702 31 013 258 665 283 516 547 81 033 825 693 953 310 343 32 013 679 697 291 192 549 82 034 227 260 770 550 632 33 014 100 321 519 620 579 83 ‘034 628 456 625 320 360 34 ‘014 520 538 757 923 700 84 | -0385 029 282 202 368 120 1-035 "014 940 349 792 936 558 | 1°085 "035 429 738 184 548 315 36 7015 359 755 409 214 218 86 "035 829 825 252 828 1438 37 ‘015 778 756 389 040 962 87 "036 229 544 086 294 540 38 | °016 197 353 512 439 047 88 036 628 895 362 161 100 39 016 615 547 557 177 412 89 | :037 027 879 755 774 956 1:040 | ‘017 033 339 298 780 355 [| 1:°090 037 426 497 940 623 635 41 ‘017 450 729 510 536 156 91 ‘037 824 750 588 341 878 42 | -017 867 718 963 505 669 92 038 222 638 368 718 428 43 "018 284 308 426 530 869 93 038 620 161 949 702 792 44 | -018 700 498 666 243 352 94 | -039 017 321 997 411 969 1 045 019 116 290 447 072 807 1-095 039 414 119 176 137 143 46 "019 531 684 531 255 434 96 "039 810 554 148 350 354 47 | -019 946 681 678 842 334 97 |} -040 206 627 574 711 132 48 020 361 282 647 707 846 98 ‘040 602 340 114 073 104 49 020 775 488 193 557 860 99 040 997 692 423 490 567 1881.] computing Natural and Tabular Logarithms, &c. ool Bimodular Table I1.—Tabular Logarithms—continued. 2. For Preparation. 5. For Full Corrections, Additive. Take six significant figures of the quotient and No. Tabular Logarithm. use six significant figures of the correction from this formula— ll 0:041 392 685 158 225 041 tab. log cor.=3 tab. log quotient+ °645 2501—1. 1:2 0°079 181 246 047 624 828 1°3 0°113 943 352 306 8386 769 ° . § 5 7 9) j re 1°4 0°146 128 035 678 2388 026 ee Quotnt. Trust places 1°5 0°176 091 259 055 681 242 . co DD) ge Lod SS SSS —— — — — — ————————————————— ————— L © 0 poet a wee 659 gz vel 0,100 | °0,434 14 And one more place in each Ly, 0°230 448 921 378 273 929 : ARS z eee of so eae - Ge =, = 0,893 | °0,888 | 15 case with a probable error in 1°8 O-255 272 505 103 306 070 "0,284 0.123 16 it of one unit in defect . a " 59 € si yack ° ey 0°278 753 aut 952 828 962 0,231 | -0,100 | 17 2-0 | 0°301 029 995 663 981 195 | 0s893 | “0.885 | 18 3°0 0°477 121 254 719 662 437 4°0 0-602 059 991 327 962 390 5°0 | 0°698 970 004 336 018 805 For intermediate Differences and Quotients trust 6-0 O°778 151 250 383 643 633 the number of places opposite the next greater. 70 0°845 098 040 014 256 831 8:0 0°903 089 986 991 943 4586 90 0°954 242 3509 4389 324 875 6. For Short Corrections, Additive, giving twelve 10 0 1:000 000 000 000 000 000 places, with a possible error of one unit in the 11°0 17041 392 685 158 225 041 twelfth place on completion. 12°0 1-079 181 246 047 624 827 Quotient. | Correction. | Quotient. | Correction. 3. Multiples of the Bimodulus. 0,000 0,00 0,353 "0,020 104 01 359 21 150 02 365 22 No. of ; 178 03 371 23 ih. Value of Multiple. 199 04 376 24 i a ey Las a eT 0,217 0,05 70,381 Ohiazo 1 | 0-868 588 963 806 503 655 5590 Re OG ars 2 Bem ienocd mols O07, oll 245 07 391 27 3 2°605 766 891 419 510 966 257 08 346 28 4 3°474 355 855 226 014 621 268 09 . 401 29 5 4°342 944 819 032 518 277 “0.278 -0..10 “0.406 0. .30 6 | 5-211 533 782 839 021 932 088 ait “410 31 7 6°080 122 746 645 525 587 296 12 415 32 8 6°948 711 710 452 029 242 305 13 419 33 9 7°817 300 674 258 532 898 313 14 423 34 = 0,320 [Onalo "0,427 0,535 327 16 432 360 ary 334 17 4. For no Corrections. 34] 18 - 348 19 Differ- : Bae. Quotnt. Trust Places For intermediate quotients take the correction Oyen oer |" 9) And one more | °PPosite the next less. 0,653 | °0,282 ! 10 place in each case 0,3U3 | *0,131 | 11 with a _ probable _ : : 0,141 | 0,609 | 12 error in it of one Note.—The natural logarithnis to eighteen places 0,653 | -0,282 | 13. unit in defect. in Table I are either taken direct or calculated (by 0,303 0.13] 14 subtracting nat. logs of 1,000 and 10) from ‘* Wolf- 0,141 “0.609 15 ramii Tabula Logarithmorum Naturalium”’ to forty- 0,653 “0.282 16 eight places, appended to Vega’s ‘‘ Thesaurus Loga- rithmorum Completus,”’ 1794. The tabular logarithms to eighteen places in Table II are taken direct from Mr. Peter Gray’s ‘“‘Tables for the formation of Logarithms and Anti- For intermediate Differences and Quo- Logarithms to twenty-four places,” 1876. tients trust the number of places opposite In both tables the arrangement and corrections are the next greater. original. MiG) KX, ae 392 Mr. A. J. Ellis. Improved Bimodular Method of [Feb. 3, correction changes. The results are given under “5. Full Correc- tions,” in Tables I and II. . But although it is by no means difficult or very troublesome to use the formule (13) and (17) for finding the first correction, it is always inconvenient to use two tables. It would be manifestly impossible to give a table of corrections to six figures within reason- able limits. Hence, leaving the “full correction” to be found, when desired, by these formule, I append a table of ‘short corrections,” so as to obtain twelve places of the result from Tables I and II at sight. The thirteenth place has been allowed for, so that the result may be thoroughly trusted, but in the ‘‘ completion” an error of one unit in the twelfth place may easily creep in unless “ full corrections ” are used. These “short corrections” haye been calculated from the formule (15) and (19), by assuming successive values of the first correction, aS °0,.9, °0,,15, °0,,25 and so on, and calculating the corresponding value of the quotients. But in the table itself these corrections are entered as ‘0,,1, °0,,2, &c. The limiting correction is reached when the corresponding quotient is the next least to that due to the number 1:001. These twelve places are fully as many as are required for ordinary purposes, and for them only thirteen out of the eighteen places in the tables should be used. 66 Section LV.—BimopuLaR TABLES AND HxAMPLES. Table I applies to natural logarithms giving from nine to sixteen places, according to circumstances, with no corrections, twelve places with short corrections, and fourteen to sixteen places with full corrections. Rule to find the logarithn from the number. — Reduce the given number to the form of a decimal fraction with an integer less than 10. Multiply and divide by such whole numbers less than 13 as will reduce the number to one less than 1:1, as shown in Section II. : Find the next less number in ‘1. Table for Interpolation,” and first subtract it from the reduced number, then omit the decimal point, and multiply by 2, forming the “ dividend;”’ secondly, add this next less number to the reduced number, and then omit the decimal point, forming the “ divisor.” Divide the dividend by the divisor by simple contracted division to as many places as are required. Correct the quotient, as may be neces- sary, by the table or formula of correction, No. 6 or 5. Add the logarithms of the divisors and the arithmetical complements of the logarithms of the multipliers used in forming the reduced number, to find the full corrected logarithm. Table II apples to Briggs’s or Tabular Logarithms, giving from nine to sixteen places, according to circumstances, with no correc- 1881.] computing Natural and Tabular Logarithms, Sc. 393 tions, twelve places with short corrections, and fourteen to eighteen places with full! corrections. ftule.—Proceed precisely as for natural logarithms, except that instead of multiplying by 2 it is necessary to multiply by the tabular bimodulus, by help of the multiples given in No. 3. Tables Land II. Rule to find the nwnber from the logarithm.—Sub- tract the logarithm of the next lower power of 10, and then, in order, the next lower logarithm in the lower, and then that in the upper part of the table ‘‘2. For Preparation,’’ and afterwards the next lower logarithm in the table for interpolation. - Py Considering this as an approximate logarithm of a reduced number, find the correction as if it were a quotient by No. 5 or 6, and subtract (instead of adding) the correction, which reduces it to the form of a quotient or approximate logarithm. Add the resulting number to and subtract it from the bimodulus (which is 2 for natural logarithms) and divide the sum by the difference. Multiply the quotient in succession by the numbers corresponding to the logarithms subtracted. The result is the number required. Heamples, fully worked out, with explanations. Let N=192 699 928 576=(76)%. Then calculating the value of 6 nat. leg 76 from Wolfram’s tables appended to Vega’s, and multiplying the result by the tabular modulus we find to twenty places— nat. log N=25°984 400 041 717 986 473 06 tab. log N=11:284 881 553 684 748 111 78 These numbers serve as checks to the correctness of the following work. Here a, 6, c form the “preparation” of N. As a begins with 1°9, where the first decimal place is more than 3 times the integer, a is multiplied by 6 to produce 11°56 . . ., a decimal fraction of which the integer 11 is less than 13 and more than twice the first integer 5. Both 5 and 4 would have also answered. The divisor 11 is separated off by ), and in the quotient c the next less number 1051 in the table for interpolation is similarly separated. This leaves c—1:051 to the right of ), with the decimal point already omitted. Then this diffe- rence is multiplied by the bimodulus 2, to obtain the dividend d. The whole of ¢ is added to the separated part 1051, and then the decimal point is omitted, giving e. As the difference c=‘0,905, lies between 0,106 and 0,495, we can certainly obtain twelve places without cor- rection (Table I, No. 4), and as it lies between ‘0,1 and °0,894 we can obtain seventeen places with full corrections (Table I, No. 5). We 2F 2 394 My. A. J. Ellis. Jmproved Bimodular Method of [Feb. 3, Er. 1, To Table I.—Find nat. log N to sixteen places. The letters refer to the following explanations. Every figure required by the most moderate calculator is inserted. a=N+10". 1. <92"- 699 928° 576 a b=6a. Lb 56 No F ae 456 b c=b—11. 1°05 1)09 051 950 545 454 54 ¢ d e 210 209 051 950 545 454 54 )18 103 901 090 909 09 DOr stats Cpa pany aa 16 816 724 156 043 63 (8 f 000 086 123 318 301 099 1 287 176 934 865 46 iy ee 53 233 1 261 254 311 703 27 (6 h 049 742 091 894 814 074 25 922 623 162 69 k * 2°397 895 272 798 370 544 21 020 905 195 05 L 8:°208 240 530 771 944 999—10 4 901 717 967 14 m 25 °328 436 022 934 502 524 4 204 181 0389 01 (2 n 25 °984 400 041 717 986 473 697 536 928 13 630 627 155 90 (8 d=2(c—1 051) x 10! =dividend. 66 909 772 23 e=2(c+1-051) x 10"%=divisor. 63 062 715 59 (8 = d+ e= quotient. 3 847 056 64 g= full correction, see below. 2 102 090 64 @ h=nat. log 1 ‘051. 1 744 966 12 k=nat. log 11. 1 681 672 41 (8 J=arithm. comp. of nat. log 6. 63 293 71 m=\11 nat. log 10. 63.062 72 CG n=nat. log N, true to 18 places. 230 99 210. 21 (Ol Caleulation of g. Log f, taking six significant places, 20 78 =log 0,861 233= -9385 1206 — 5 13) 92°08 3 log f=2 805 3618 —15 1 86 + °920 8188 — 2 1 29249 log g=log 0,3532 329= -726 1806 —14 prepare, then, for seventeen places, by carrying the quotient ¢ far enough to allow of obtaining eighteen places, that is, fourteen signifi- cant places of the quotient f. As at least 2 digits of the divisor must remain for the last contracted divisor, we shall require only fifteen places of the divisor, and the last five are rejected (shown by drawing a line under them). The successive digits of the quotient are written to the right after ( (following Briggs’s use), and are collected inf. The rest of the process is evident from the notes 1881.] computing Natural and Tabular Logarithms, &c. 399 made. The result happens to be correct to eighteen places, in place of the guaranteed seventeen; but this is quite accidental, as the last or eighteenth place of all the logarithms used is always in excess or defect. Hz. 2. To Table II.—Find tab. log N to twelve places by the short corrections. a=—=N—10. b=5a. c=—b+9. d=5 X bimodulus x 1029. alee. K198: hoe anos: xX bY ox “e a=l'x ‘ aod 59 8x - 7X 4 ox A ox 5 ox <4 6 xX i r 699 928 576 880 19 9) 6 499 642 iL - O)55 515 875 556 43 429 4, 342 434: 08 4, & bo 412 Mr. A. J. Ellis. On the Potential Radix, §&¢. [Feb. 3, 1 ‘004 a | 1 004 006 004 OOL b=(1 ‘001)4, next greater 2-008 006 004 001 b+a, divisor 12 008 002 2(b—a), dividend 000 005 980 062 796 661 85 2(b—a)+(b+a), quotient Ore 17 82. correction= 7, x ((0,5980) 000 005 980 062 796 679 67 log b—loga 003 998 001 332, 334 132 67 logb 003 992 021 269 537 453 00 log a=log b—(log b—log a) The result is correct to the last or twentieth place. If we had formed log a from the next less or (1:001)%, the difference between the numbers would have been so large that the result would have been correct to thirteen piaces only, and we should have required higher stages in the radix to obtain twenty places. Hence the nearest number should always be selected. To find —nat. log (1—‘004) =—nat. log -996, we should deduce it from—nat. log. (1— ‘001)*, and as the difference in this case, which is always the approximate quotient, and hence logarithm, is less than ‘0,6, and ~; x (‘0,6)’="0),18, we should obtain sixteen places without correction, and four with correction, or twenty places in all. We thus proceed to form the whole of this stage of the numerical radix, but we cannot obtain twenty places in all cases. Thus for 1:009, the difference from (1:001)? is -0,36084, the quotient is "0,3508, and the correction=~, x (0,3508)’='0),3594, so that we should obtain only eighteen places, that is to say, although the potential radix is calculated to twenty-one places, it will not furnish a numerical radix of more than eighteen places when we begin with the stage 1°0,1, and hence will not give logarithms of general numbers to more than sixteen places certain. In the stage 1°01 the radix of that stage will not furnish so many places, and we have to reduce to the preceding stage, which is now supposed to be fully calculated for both the positive and negative numerical radixes. Thus for nat. log 1:04 as derived from 4 nat. log 1:01, the difference is °0,6040, giving correction ‘0,)1856, and hence fourteen places. But on dividing by 1:04 we obtain 1:0,58 ... and the difference from 1°0,6, of which the natural logarithm in a pre- ceding stage is known, is 0,2 .. ., the logarithm of which can be found to eighteen places. If more still were required we should divide by 1:0,5, obtaining 1:0,8 . . . of which we can find the logarithm through that of 1°0,8, to twenty places at least. Hence ifthe potential radix has been commenced ata sufficiently high stage and to a sufficient number of decimal places, a numerical radix for natural logarithms can be calculated to any number of places, and from it the natural logarithm 1881.] On the Musical Pitch of Harmonium Reeds. A13 of any number, such as the modulus of any other system of logarithms can be found, and its reciprocal, whence the radix for that system can be calculated by simple multiplication. This is sufficient to show the practicability of the present method, and generally the comparatively small trouble which it would occasion for the first construction of logarithmic tables. VI. “On the Influence of Temperature on the Musical Pitch of Harmonium Reeds.” By ALEXANDER J. ELLIS, B.A., F.RB.S., F.S.A. Received January 17, 1881. In my “ Notes of Observations on Musical Beats,” I stated (“‘ Proc. Roy. Soc.,” vol. 30, p. 532) that the influence of temperature on harmonium reeds was, so far as I was aware, unknown. Since then I have made some observations which at least approximately deter- mine it, but there are so many sources of small errors (stated below) that still more uncertainty must attach to the results, than to the determination of the influence of temperature on the pitch of tuning- forks (ibid., p. 523). Roughly we may say that the pitch of harmo- nium reeds is affected in the same direction as that of tuning-forks (heat flattening and cold sharpening), and very nearly to twice the amount, that is, by about 1 im 10,000 vibrations for each degree Fahrenheit. The following is the process pursued with the exact figures obtained :— Towards the end of November, 1879, in the South Kensington Museum, with artificial temperatures (observed in each case) varying from 53° to 60° F. on different days, I determined the beats which all the reeds of Appunn’s treble tonometer (ibid., p. 527) made with Scheibler’s forks (vbid., p. 525). On Ist September, 1880, and again on 3rd September, 1880, at constant natural temperatures of 73° and 79° F. respectively, I took the beats of twelve of the reeds (the same on each occasion) with the same forks of Scheibler with which I had measured those reeds in November, 1879. It is, of course, impossible to say whether either forks or reeds were precisely of the same temperature as the air. The reeds were inclosed in the wooden chest of the tonometer, which had been reposing in a olass wall-case in the same room during he night, and might not have fully acquired the general steady temperature of the room. The beats for each reed were counted 10 times each for 10 seconds, with each of two, and sometimes three forks, and the mean of each set of beats was employed. The known pitch of the forks at 59° F. (dbid., p- 525) was then reduced to the temperature of the observation on the supposition that the number of vibrations altered by 1 in 20,000 for Al4 Mr. A. J. Ellis. On Influence of Temperature [Feb. 38, 1° F. (ibid., p. 523). By adding or subtracting the mean of the observed beats from this calculated pitch of the fork, the pitches of the harmonium reeds at those temperatures were determined, and the mean of all the determinations for each reed was taken. Im all cases I calculated to two places of decimals, but the second place cannot be depended on when counting the beats; and as the result is consider- ably affected by the second place, the process is not so satisfactory as could be wished, and must be regarded as only preliminary. The loss of pitch in proceeding from the lower to the higher temperatures thus determined was divided by the number of vibrations at the lower tem- perature, and also by the number of degrees F. of difference of tempe- rature. The result or coefficient of temperature, being the alteration for 1 vibration and 1° F., would serve to reduce one pitch to the other, on the supposition, which cannot be more than approximately correct, that the alteration for temperature is uniform, and is the same for reeds of very different pitches and makes. Such a coefficient is, how- ever, clearly better than none at all, and is especially useful in deter- mining pitch by Appunn’s instrument. In the following table the number of the reed is that marked on Appunn’s treble tonometer (ibid., p. 527). The “pitch” means the number of double vibrations in a second made by the reed, on the three occasions of observation already mentioned, and as the tempe- rature was variable during the first observations, made on different days, though constant on the same day, this is annexed in a separate column. As harmonium reeds are subject to rather sudden small alterations from causes not yet investigated, it is not possible to be perfectly sure that all the reeds would have shown precisely the same pitch at the same temperature for observations made at intervals of more than nine months. Iam inclined to think that reeds 22 and 23 must have so altered. In other observations on reed 22, made 14th July, 1880, at 71°°5 F., I obtained practically the same results as here, differing from those of all the other reeds. The observations on that day were not sufficiently numerous nor exact to be here recorded, but they agree very well with those now given. The flattening of the reeds for each increase of temperature is quite unmistakable, even in the passage from pitch II to III, with a difference of only 6° F. The pitch III of reed 26 is certainly a bad observation, as the results of the determinations by the two forks differed much more than usual, and it should, therefore, be thrown out of consideration. Altogether for such a small difference as 6° F. the observations could not be made with sufficient accuracy to secure trustworthy results. Even for the greatest difference of temperature, 26° F., the difference of pitch never amounts to so much as ‘9 vibration in a second for the reeds observed. The three last columns give the coefficients of temperature arising from comparing these three pitches two and two, namely, I and II, 1881.] A15 Tand III, Iland III. The results marked + should, I think, be re- jected, because of the probable alteration in reeds 22 and 23, the badness of the observation on reed 26 pitch III, and the too great closeness of the temperatures for pitches Il and III. Rejecting these, we obtain, as the mean of the results from I & II, and II & III respec- tively, the coefficients 0000938 and -0000930; so that either ‘00009 or ‘0001, that is, an alteration of 9 in 100,000 or 1 in 10,000 vibrations in a second for each change of 1° F. may be used with tolerable certainty, diminishing for heat and increasing for cold. Thus a tuning-fork like Scheibler’s of 440 vibrations at 59° F. (his standard tuning A), an harmonium reed like Appunn’s, and an open metallic flue-pipe of an organ, both in unison with the fork at the same tempe- rature (the last having a coefficient of ‘00104 acting in the opposite direction) would become 439°56, 439°12, and 44915, at 79° F. respec- tively, so that it would be quite impossible to play the organ and harmonium together. on the Musical Pitch of Harmonium Reeds. Table of the Pitch of Reeds at different Temperatures. Pitch of the Reed. Coefficient of Temperature. No. of |—--—_, 3 Aiea Reed I ah II at III at From From From PBs) 79°. Tand II. | I and III. | Iland III. (6) 25404 | 55°5 | 253°67 | 253°55 | -000 0844 | 000 0976 |+:000 0723 3 266711 eS 26555 | 265-41 1192 © 1114 +816 9 289°96 55 289°45 289°30 1159 948 7864 14 309 66 ss 309°18 | 3809°06 861 807 +647 22 B4Ie3h | 53° 340°91 | 340°76 +586 +620 +733 23 345°35 is 34488 | 34465 +680 +780 +1112 25 35350 ie 352°92 | 352°66 820 914. +1223 26 ao7 ok ty 356°9U | +356°85 853 +1125 +0234 33 385-30 | 59° | 38477 | 38464 945 960 +563 36 B20) 5, 396°75 | 396°55 809 818 +840 43 42448 | 60° 424-42 | 424°23 1014 929 +746 AG AeG Zl |, 436-21 | 435-96 881 904 4955 Mean, rejecting results marked +, 000 0988 | -000 0930 416 Capt. W. de W. Abney. On the [ Feb. 10, February 10, 1881. THE PRESIDENT in the Chair. The Presents received were laid on the table, and thanks ordered for them. The Right Hon. Mountstuart Elphinstone Grant Duff was admitted into the Society. The following Papers were read :— I. «On the Influence of the Molecular Grouping in Organic Bodies on their Absorption in the Infra-red Region of the Spectrum.” By Captain W.pE W. ABNEY, R.E., F.R.S., and Lieutenant-Colonel FEsTiInc, R.E. Received February 5, 1881. (Abstract.) The authors describe the apparatus used by them in their research and their plan of mapping the absorption spectra, the results being given in wave-lengths. The source of light for obtaining a continuous spectrum was the incandescent positive pole of an electric light, the electricity being generated by an M. Gramme machine. The light was passed through tubes containing the fluid, and the absorption spectra photographed in the infra-red region. The absorptions they met with they class as follows :— lst. General absorption at the least refrangible end of the spectrum. { Fuzzy. Sharp. Both edges sharply defined. Bands : Lines .. One edge sharply defined. Both edges less sharply defined. The authors next discuss the causes of the different absorptions met with in various fluids. From experiment they show that a large number of lines which are formed in hydrocarbons containing no oxygen are common to substances containing hydrogen and no carbon, and that in carbon tetrachloride and carbon disulphide, no lines or bands are to be met with. By this eliminating process they deduce the fact that the presence of lines is due to the hydrogen in the bodies. 1881.] Influence of Molecular Grouping, &§e. 417 They show that the termination of the bands in liquids contaiming carbon, hydrogen, and oxygen corresponds with the position of these hydrogen lines. It therefore appears to them that the bands are in reality a blocking out of radiation between two hydrogen lines. By increasing the thickness of the fluid in front of the slit, the bands may be widened to another hydrogen line, each hydrogen line acting as a stepping-stone, or they may remain constant if both edges are defined, or they may be obliterated by general absorption. On the other hand, lines may be spread out to bands as the thickness of liquid is increased. When the thickness of the fluid is diminished the lines may disappear, and the bands become lines, or the bands may remain constant though fainter. The authors then point out that each radical has its own definite absorption in the infra-red, and that such a radical can be detected in a more complex body. Italso seems possible that the hydrogen which is replaced may be distinguished by a comparison with other spectra. They next point out coincidences between some of the lines obtained, the absorption spectra of the hydrocarbons, and the spectra of bodies containing no carbon with solar lines, from which they reason that at present it is not safe to infer that such lines in the solar spectrum are not necessarily due to water. Whether the lines mapped are due to hydrogen or not, it is perfectly evident that every organic body has a definite absorption spectrum which connects it with some series. The paper closes with an appendix giving tables of the bands and lines found in the following substances, of which also there are maps :— Methy! iodide. Ethyl sulphide. Acetoacetic ether. Ethyl iodide. Aldehyde. Diethyl acetoacetic ether. Propy! iodide. Paraldehyde. Benzylethyl ether. Amyl iodide. Formie acid. Methyl salicylate. Phenyl! iodide. Acetic acid. Cinnamice alcohol. Ethyl bromide. Propionic acid. Phenylpropyl alcohol. Amyl bromide. Methyl alcohol. Ethyl alcohol. Propyl alcohol. _ Isopropyl! alcohol. Tsobutyl alcohol. Pseudobutyl alcohol. Amy] alcohol. Diethyl ether. Amy! ether. Ethyl nitrate. Ethyl! oxalate. Tsobutyric acid. Valerianic acid. Glycerine. Benzene. Phenyl bromide. Benzyl chloride. Nitrobenzole. Aniline. Dimethyl aniline. Turpentine, Olive oil. Dibenzy! acetic ether. Allyl alcohol. Ally sulphide. Anethol. Citraconic anhydride. Water. Nitric acid. Hydrochloric acid. Sulphuric acid. Ammonia. Chloroform, 418 Dr Vi Marcet. [ Feb. 10, If. “Experiments undertaken during the Summer, 1880, at Yvoire (1,230 feet), Courmayeur (3,945 feet), and the ‘ Col de Géant’ (11,030 feet), on the Influence of Altitude on Respiration.” By Win~iiAM Marcet, M.D., F.R.S. Re- ceived January 24, 1881. Former communications on the influence of altitude on respiration have appeared in the ‘“‘ Proceedings of the Royal Society” for 1878 and 1879. I have continued the inquiry; and my present object is to give an account of my latest investigations on that subject. I must beg leave to premise that'a work of this kind is not free from difficulties; some of these are of a physiological nature, and refer to the task of taking into account the different circumstances bearing on the state of the body at the time of the experiment ; respiration is, if I may so express-it, so delicately balanced in its relations with the other functions, that any one of them becoming either quiescent or in a state of activity reacts immediately upon it. Then the capacity of the bags for collecting the air expired gave some little trouble to determine accurately ; and, moreover, the manipu- lations, which would require both care and practice to be carried on satisfactorily in a laboratory where all that can be wanted is at hand, were found much less easy to perform in the open air, at the summit of some high mountain, in a cold cutting wind, and where the omission of a trifling article, such as a cork or a piece of string, might render much labour useless. There is also a circum- stance in a work of this kind having a tendency to detract from the value of its results, inasmuch as what is observed with one person may not apply to another. It is not easy to find many people ready to submit to a stay of several days in the Alps, at altitudes ranging up to 10,000 feet and above; and I know by experience that the increased _ length of time required to repeat the experiments on different persons may prove very inconvenient. This last summer, however, I was most fortunate in obtaining the company and help of a young gentle- man from Geneva, M. Hlie David, the assistant of the Professor of Natural Philosophy at the University of that town, Professor Wart- mann. M. David submitted to experiment with great patience and much intelligence, and the results obtained on both of us may be accepted as perfectly trustworthy. My method of investigation has been much improved since my last paper was communicated to the Royal Society, and the substitution of the vacuum process for the aspiration with water, in order to transfer air from the bag into the cylinder for analysis, has added not a little to the accuracy of the results. New and larger india-rubber bags than those used at first have been made, of improved material, and 1881.] On the Influence of Altitude upon Respiration. 419 their capacity has been determined with the greatest care by means of a gas-holder or bell-jar, having a scale of cubic feet divided into hundredths and tested as to correctness. I must beg to take this opportunity of returning my best thanks to Mr. Henry Sporne, Inspector of Gas Meters for the city of London, for his kindness in determining in my presence the capacity of the bag used in these experiments, by means of one of his beautifully graduated gas-holders, made for testing the delivery of gas meters. The capacity of others of my experi- mental bags was ascertained by the same means. The bulk of air held by the bag employed in all the experiments referred to in the present communication was determined as follows :-— The gas-holder having been filled with air, and the pressure of the in- strument regulated to one inch of water, it was placed in communication with the bag laying flat and quite empty on a table. This bag was also connected through one of its necks and india-rubber tubing with another water-gauge. All these connexions being perfectly air-tight, the height of the air-holder was read off, and the air admitted into the bag from the holder. After some minutes the bag became fully dis- tended, and the water began rising in the gauge connected directly with it. As soon as a pressure of one inch in the bag was attained, the delivery from the air-holder was read off; it had by that time all but done falling, moving downward very slowly, to the extent of a delivery of about one-hundredth of a cubic foot and then stopped; if the bag was then handled, one or two more hundredths of a cubic foot might be given out from the holder. One experiment gave a delivery of from 4 to 7:18 on the index = 3:18 cubic feet, read off as soon as the water in the gauge connected with the bag showed a pressure of one inch; on waiting two or three minutes, 3°19 cubic feet were read off; and, after handling the bag, the volume of air delivered into it rose to 3°22 cubic feet. In another experiment the reading on the holder was made to commence at 6, and when the bag was full it had fallen to 9°19, giving a bulk of 5:19 cubic feet of air delivered into the bag; after handling the bag, the air given out rose to 3°22 cubic feet. I have therefore taken 3°20 cubic feet, or 90°6 litres, as the correct estimation of the air contained in the bag under the pressure of one ‘inch of water. In this last experiment the temperature of the air in the bag was ascertained to be the same as that of the room, and, moreover, the holder had been filled with air for some hours previously, so that it is very unlikely that its temperature should have been different from that of the external atmosphere; the temperature of the water in the gas-holder was a trifle below that of the room. I proposed this last summer to make the Col du Géant (altitude 11,030 feet) my highest experimental station, as this spot was easy to reach with the necessary instruments, and a small wooden hut had been lately erected at the summit of the pass, where we could make 420) Dr. W. Marcet. [Feb. 10, our residence during our stay at that place. The experiments were repeated at Yvoire near the Lake of Geneva (altitude 1,230 feet), and at Courmayeur (3,945 feet) at the foot of the Col du Géant on the Italian side. Hence, there were three series of data obtained in the course of about three months on two persons in good health, though very different in age, weight, and other respects. ‘Two sets of experiments were made at Courmayeur, the first before ascending to the Col du Géant, and the second on our return; the object being to ascertain whether the influence of the sojourn at the higher station showed itself on our breathing for some time after we had left it. The experiments were invariably made in the sitting posture, and in the open air, away from every possible source of contamination with carbonic acid, and care was taken to remain perfectly quiet for a short time before collect- ing the air expired. With the object of determining the amount of air expired within a given time, and the carbonic acid it contained, breathing was carried on through a face-piece connected with the india-rubber bag, and adapting itself perfectly over the mouth and nose; the face-piece was supplied with valves, so that fresh air was taken in at each inspiration, while the expired air was collected in the bag. P.M. of the 21st, in three succeeding days had long intervals of complete immobility. On the 25th, at 4h.2m. A.m., another slight shock was felt; this, although of small intensity, we have faithfully transmitted to paper, because, in our opinion, it is important to show the gradual change of focus of seismic radiation during the whole time. The direction of the undulation was from H. 26° N. to W. 26°S., and only reached a total amplitude of 3° 45’. The movement of trepi- dation was inappreciable, as the index of the vertical pendulum departed only 0-7 millim. from its normal position. 1881.] Notes on the Karthquakes of July, 1880, at Manila. 467 “We will now recapitulate briefly what we understand by the figures. | “On the 14th, which is that represented in fig. 1, we notice two foci of seismic radiation, the first situated in the second quadrant, wher eit began, and the second situated in the first quadrant, where it terminated. In the earthquakes of the 18th we also discover the same two foci; but two others also appear which impelled the pen- dulum in every imaginable direction, as may be seen in fig. 2. “ Proceeding to that of 3 p.m. on the 20th, we find that the focus of the second quadrant acted with astounding violence, and the others disappeared (fig. 3). We turn now to fig. 4, which represents to us the violent repetition of 10 p.m. on the 20th, and we observe a great variation with regard to the foci of seismic radiation. In it we see that the oscillations from east to west, and which correspond to the focus, which before had acted with so much violence, were gradual and of much less intensity. On the contrary, that from north-east to south-west showed a great degree of undulation from these points. HIG, 5: ‘“‘ Finally, in fig. No. 5, which represents the last important oscil- lation on the morning of the 25th, we only note the focus of seismic radiation of the first quadrant operating with very little intensity, the other foci having entirely disappeared. We do not care at present to form deductions from the above observations, we have preferred to present them to general notice in order that scientific persons might form their own conclusions without being biassed by our opinions. ‘“‘Note Ist. Observe, that in speaking of the swing of seismic un. dulation from both sides of the centre of reference (place of instru- ment), we do not mean to say that the buildings moved from one side to the other like the pendulum, because it is very clear that the latter was only moved in one of the semi-undulations by the effect of the 468 Commander Wi B. Pauli. [Feb. i, impulse, or inclination, of the building, the other being the effect of the velocity acquired in the first semi-oscillation. The object of alluding to the double motion on either side of the centre of reference was to give freedom to the opinion which some people held, that earth- waves are similar to waves of sound in the air; while others aver that they are caused by the rising and sinking of the ground in localities more or less distant from the post of observation. ‘“‘ Note 2nd. A great number of lines will be observed in the figures which appear not to be connected with the rest; we can only explain the fact as being caused by frequent vertical shocks, jerking the pendulum violently and causing it to leave one curve to follow another commenced by the new impulse. ‘We can assure our readers that the curves as they are repre- sented in the different figures were transferred from the lycopodium to the paper with the greatest fidelity.” This ends Father Faura’s observations on the earthquakes, and in forwarding these he informs me that he will later on publish a more complete account. He is also engaged in establishing stations for meteorological observation in various parts of Luzon—which will be in telegraphic communication with Manila—and thence with Hong Kong; the chief object being to announce the advent of typhoons. As these storms invariably travel from about east by south, or east- south-east to west by north, or west-north-west, the Philippine islands, especially Luzon, are well situated for the object of giving _ storm warnings to the coast of China. No doubt these stations will also be supplied with mstruments, and receive instructions to observe the direction and force of earth-waves. If such stations had existed in July, the accounts would have been more complete and useful, and although reports from many places are recorded, they are in most cases unreliable and contradictory, and deal chiefly with the destruction caused to buildings, loss of life, and ‘Injury to persons. The captain of the British steam-ship “ Esmeralda,” then at anchor in the Bay, states that in the earthquake at 6 p.m., on the 20th July, ‘“‘ the water bubbled and boiled up noisily allaround the ship and the vessel tossed as if in a heavy gale;” that the wreck of a ship (which had been sunk for some years) ‘‘ was thrown right up out of the water and one of her iron masts was seen to give way.” He describes the sensation on board ship as well as on shore as that “of being suddenly connected with a galvanic battery strongly charged,” and as being a “ tremendous strain on the nerves.” Accounts are also given of fissures in the ground in various places, from which sand and water were emitted, especially in the neigh- bourhood of the Laguna de Bay, where hot sulphur springs have always existed. 1881.] Notes on the Karthquakes of July, 1880, at Manila. 469 I will now give a translation of a letter to a local paper from a resident near the spot, giving an account of the behaviour of the Volcano of Taal before and during the earthquakes of July. This letter was written in consequence of exaggerated reports of great eruptions of that volcano, and professes to give a true relation of the facts. “The crater of the Volcano of Taal ceased to send up smoke as usual on Monday, 12th July. At nightfall on Wednesday the 14th, subterranean noises were heard, and a heavy swell was observed in the lake ”’ (the volcano is on an island in the Lake of Taal), ‘“‘ which ceased after the earthquake of the same night; louder subterranean noises were heard during the earthquake. “On Thursday the 15th, two columns of smoke continued to issue, with intervals, until the 16th, when they almost disappeared, and the volcano subsided to its usual state. “On Sunday the 18th, in the neighbouring villages of Tanauan, Sto. Tomas, and Talisay, and nearly as far as Lipa, a fog of smoke, with smell of sulphur, was observed, which disappeared suddenly at noon; a short time after occurred the violent earthquake of Sunday, at 12h. 40m.p.m. In the afternoon of the same day, the 18th, the volcano again threw up the two columns of smoke, at intervals, until Tuesday the 20th, at 10h. a.m., when it ceased smoking entirely. In the afternoon, at 3h. and some minutes, the violent earthquake, felt at Manila, which was also most intense at Batangas and towards the Laguna, occurred... From eight to ten on Tuesday night, a brightness was seen over the volcano, as if reflecting the hight of fire from the crater on the vapours which arose from it. This brightness ceased suddenly and the atmosphere cleared entirely, and at ten began the strong shocks of earthquakes, the first being the violent shock felt in Manila. These continued in the Province of Batangas ”’ Gn which Taal is situated) ‘“‘during the night and were sensible for several days. “On Wednesday the 21st, in the morning, the volcano threw up a great quantity of smoke, to a considerable height, in one column, the whole size of the crater, and continues to do so up to the time of writing this notice. “In the evening, the Volcano of Maquiling, which had been con- sidered extinct, gave forth much smoke, which caused terror in-the province, because the people feared the crater there would break out again, and they called to mind the terrible eruption of the Volcano of Taal, on 12th December, 1754, when the lava destroyed the villages of Tanauay, Sapa, Lipa, and Taal, which villages were after- wards rebuilt in a position more remote from the volcano.” Among other strange phenomena recorded, it is stated from other sources that the great mountains of Banajoa, Maquiling, and San 470 Prof. G. G. Stokes. On a Simple [Feb. 24, Cristobal were observed at the time of the earthquake to be covered by clouds of, to all appearance, gaseous vapour; and the Padre Bravo, Curate of Lilio, asserts, that the movement of Banajoa was so awiul to behold that residents of that village, situated at the base of the mountain, feared that it would fall over and bury them beneath it. The two sheets containing diagrams of the five principal shocks were lithographed at Manila, under the careful supervision of Father Faura, and I thought it better to send them as received rather than attempt a tracing, the lines being so complicated. I have not appended a translation of the few descriptive notes on the sheets, as the terms used are almost identical with their English signification. February 24, 1881. THE PRESIDENT in the Chair. The Presents received were laid on the table, and thanks ordered for them. The following Papers were read :— I. “On a Simple Mode of Eliminating Errors of Adjestment im Delicate Observations of Compared Spectra.” By Pro- fessor G. G. STOKES, Sec. R.S. Received February 12, 1881. When the identity or difference of position of two lines, bright or dark, in the spectra of two lights from different sources has to be compared with the utmost degree of accuracy, they are admitted simultaneously into different but adjacent parts of the slit of a spec- troscope and viewed together. It was thus, for instance, that Dr. Huggins proceeded in determining the radial component of the velocity of the heavenly bodies relatively to the earth. It is requisite that the two lights that are to be compared should fall in a perfectly similar manner on the slit: and it will be seen, from a perusal of his paper, how careful Dr. Huggins was in this respect. In a paper read before the Royal Society on the 3rd instant, Mr. Stone has proposed to make the observation independent of a possible error in the exact coincidence of the lights compared by constructing a reversible spectroscope, by which the light should be refracted alternately right and left, supposing for facility of explanation the slit to be vertical. 1881.] Mode of Eliminating Errors of Adjustment, &¢. A71 The idea is an elegant one, but I apprehend that there would be considerable difficulty in carrying it out. For a spectroscope giving large dispersion is of considerable weight, and the reversal of so heavy an apparatus would be liable to introduce possible errors arising from flexure.* It would be difficult to make sure that such did not exist, at any rate, unless the instrument were constructed with great nicety and firmness, which would add considerably to the cost; and even then the care and time required for the reversal would help to oblite- rate the observer’s memory of what he had seen in the first position of the instrument. A method has occurred to me of effecting the reversal without re- versing the spectroscope, but merely giving a lateral push to a little apparatus which need not weigh more than a few grains. If the base of an isosceles prism be polished as well as the sides, and a ray of light parallel to the base and in a plane perpendicular to the edge fall on one of the equal sides of the prism so as to emerge from the other, after suffering an intermediate reflection (which will necessarily be total) at the base, its course after refraction will be parallel to its course before incidence; and there will, moreover, be no lateral displacement, provided the lateral distance of the base from the incident ray be such that the point of reflection is at the middle of the base. ; If the slit of the spectroscope be covered by such a prism, placed close to the slit and facing the collimating lens, to the axis of which its base is parallel, it will not disturb the general course of the light incident on the spectroscope, nor even produce a lateral displacement provided the lateral position be that mentioned above; but in conse- quence of the reflection there will be a reversal as regards right and left, and any error in the placing of the lights to be compared will thus be detected and eliminated, by comparing the spectra seen with the light from the slit direct or reflected. If the prism be placed quite close to the slit it may be made very minute in section, though it should be long enough to cover the slit, and then the change of focus which it produces will be insignificant. There will be no need, however, to make the prism so very minute, nor to place it so close to the slit, provided it be associated with a plate to take its place in the direct observation, and compensate for the change of focus which is produced by its introduction. Let ABCD be a section of the prism, let M be the middle point of the base AB, KLMNO the course of a ray passing as above described, which is supposed to be the axis of the pencil coming through the * After the present paper was sent in to the Society, I was informed by Mr. Stone that the spectroscope he had in his mind was a direct-vision one, which could be turned in its socket, the slit and cylindrical lens remaining fixed. To such an instrument the objection as to flexure would not apply. MOB. XXXI. 21 A772 On Eliminating Errors of Adjustment, §c. [Feb. 24, middle of the slit. Let ¢ be the angle of incidence, which will be half the angle of the prism, and the complement of either angle A or B, @ the angle of refraction, » the index of refraction, b the base AB, I the length of path, LM+ MN, of the ray within the glass, p=LN. In spectroscopic work it is the focus of rays in the primary plane that we have to deal with ; and we get for the shortening (s) of the focus, or,in other words, the distance by which the slit is virtually brought nearer to the collimating lens, But since MBL=90°—¢ and MLC 90°—q@’ we have 1=p°8P , also p=l cos (6—¢’) ; cos whence s=b cos (GW) = p ercomg ale ={1- *) cos gp’ pb cos? @ where ¢ is the thickness of a compensating plate which shall produce the same shortening of focus. In the figure, the part of the prism which is out of use is represented as cut away, to make the instrn- ment more compact, and HFGH represents the compensating plate. The faces CD of the truncated prism, and EF, HG, of the plate, of course need not be polished, and had better perhaps be blackened. In the figure I have taken 80° for the angle of the prism, and sup- posed yx to be 1°52, which data give t=1:225), nearly. A blunter angle would have made the instrument a little more compact in the direction AB, but I wished to avoid needless loss of light by the two reflections that accompany the refractions. The size of the prism and compensating plate must depend upon its distance from the slit, and 1881. ] Notes on Physical Geology. 473 the angle subtended at the slit by the objective of the collimator. It should be a little larger than what is just sufficient to take in the largest pencil that is to be observed, but not beyond that. The object in keeping it as small as conveniently may be, is that only a trifling change of focus may be required when the instrument is pushed aside altogether, and the slit viewed directly through the spectroscope, without the slight loss of ight due to the two reflections, The compensating plate is represented as placed at the narrow end of the prism, which permits of the two being cemented together, thereby facilitating the support. I do not think that the minute quantity of light which is reflected at L, and scattered at the surface (even though blackened) FC in such a direction as to mingle with the direct light would be any inconvenience, being too faint to be visible at all. Ifit were wished to avoid this, or to get more easy access to the surfaces AD, BC, for cleaning if requisite, the plate might be placed at the other side; but in that case it must not be cemented to AB, as that surface is wanted for total reflection. The little instrument I have suggested may conveniently be called a slit-reverser, to distinguish it from other arrangements which have been proposed, and in which the spectrum itself is reversed. P.S. Feb. 21.—The method proposed above is more directly appli- eable to such an object as the comparison of really or apparently coincident lines in the spectra of two elements than to astronomical measurements, because in the latter case a great part of the difficulty arises from a want of perfect accuracy in the clockwork movement of the equatoreal. Yet I cannot help thinking that even for astronomical work the method will be found useful; for we can pass in a moment from the direct to the reflected image of the sht, and vice versd, and by taking the measures alternately in the two modes, and combining them exactly as in weighing with a balance that is still swinging, any error progressive with the time would tend to be eliminated. II. “Notes on Physical Geology. No. VII. On the Secular Inequalities in Terrestrial Climates depending on the Peri- helion Longitude and Eccentricity of the Earth’s Orbit.’ By the Rev. SAmuEL HaucurTon, Professor of Geology in the University of Dublin. Received February 19, 1881. The attention of geologists was first called by M, Adhémar, and afterwards more fully by Mr. James Croll, to the possible importance of these long inequalities in climate, in explaining the climates of geological periods, which differ considerably from those of the present 242 ATA Rev. 8. Haughton. [Feb. 24, time in the same places; but, so far as I know, no one has written down these inequalities in a mathematical form, or calculated nume- rically the effects upon climate they are capable of producing. I shall attempt to do so in the present note. The temperature of any place at any time depends upon sun-heat and terrestrial radiation, and involves the solution of the following differential equation :— dé@__Adg(z) dt r where 0=temperature of place in Fahrenheit degrees, LR(@+a) 4 ot. A=a solar constant, @(z) =a known function of the sun’s zenith distance, 7=distance of earth from sun, B=a local atmospheric constant depending on latitude and local conditions, a=another local atmospheric constant depending on latitude and local conditions. When the absorption of sun-heat by the atmosphere is neglected (2) =cos z, and the first term of the equation can be integrated for one day in terms of t, and afterwards summed for all latitudes, for one year; but when we take account of the absorption of sun-heat by the atmosphere, @(z) becomes an exponential function of cos z, that cannot be inte- - grated, even by series. It has been shown, however, that, whether we take account of the _atmospheric absorption or not, the quantity of sun-heat represented by I) taken for the whole summer is the same, at similar latitudes, Fe in the northern and southern hemispheres; and, in like manner, the winter sun-heats are the same in the two hemispheres, whatever may be the perihelion longitude and eccentricity of the earth’s orbit. This being so, the secular inequalities of climate under discussion, must arise from the second term of equation (1), depending on terres- trial radiation, and ultimately on the fact that the summers and winters in the two hemispheres differ in length, that difference depend- ing on the perihelion longitude and eccentricity, as is well known. Before discussing the second (or radiation) term of equation (1), I shall explain my reasons for assuming it to have the form —B(0+a), and show what that form implies. 1881. ] Notes on Physical Geology. 475, The heat received from the sun by the layer of atmosphere next the ground is dissipated in the following ways :— 1. By convection, or ascent of the warmer surface air into the higher layers of the atmosphere, until it is cooled down to a temperature* a, such that its direct radiation into space is equal to the heat received from the sun and lower layers of the atmosphere at that height in the atmosphere. | 2. By conduction, or transfer of heat from layer to layer, as in solids. 3. By direct radiation from the surface layer across the atmosphere into star-space. The third of these sources of loss of heat may be neglected, because the atmosphere, which absorbs about one-fourth of the luminous sun- heat passing through it vertically, will absorb nearly all non-luminous heat and allow only an infinitesimal fraction to escape into star-space. The first source of loss of heat (convection) is much more influential than the second (conduction), but for my present purpose it is not necessary to make any distinction between them, for the loss of heat from both causes will follow the same law and is proportional to the difference of temperature between the surface layer of the atmosphere and the upper, or equilibrium control layer; that is, the loss of heat is proportional to (@+a). The radiation is therefore represented by Radiation= B(@+a)dt. This expression cannot be summed without assuming some relation between 9 and ¢, which I do as follows:—It is well known that the diurnal temperature does not reach its maximum and minimum at midday and midnight, but some hours after the sun’s passage of the upper and lower meridian ; and it is also well known that the hottest and coldest days of the year do not occur at midsummer and mid- — winter, but some days after. This law of diurnal and annual change of temperature presents so close an analogy to the law of the diurnal and annual tides, as to justify us in assuming for its mathematical expression formule similar to those of the well-known equations of the diurnal and annual tides. I therefore assume— oT a, cosh % Ceri Le eee Paro eee ce Ged where @)>=mean diurnal temperature, h=sun’s hour angle. * As ais probably below zero for all latitudes, I shall reckon it positive below zero, and @ positive above zero. A76 Rey. 8. Haughton. [Feb. 24, Integrating (2) for one day, we have— Diurnal radiation=27B(@)+a)- - . «-. (8)- Again, assuming = a, cos L Oo = Onde e int i asm le where @)=mean annual temperature, 1=sun’s longitude. Summing for the whole year, we find— Annual radiation=3((0)+a) +4 tao ee nt) Ob. +p) re but, by the theory of the earth’s motion, we have— ae T(1—e?)> Z 60 t= a 6), Qar (1+e cos 6)? (6) l=0+oa, where T=earth’s periodic time of revolution, e=eccentricity of earth’s orbit, 6=true anomaly, #=earth’s perihelion longitude. Substituting in (5) and summing, we find, for the year, Anrmolisendintion=2nb Ul): yx 4 (a1 +52) +0) (2 es se} (7); or, neglecting quantities of the order of the square of the eccentricity, | sin (OF Necealedtitan 2 at ( (+a) + gy 8 =e) en From this equation, we find— Secular range of temperature=2eVa2P2+B2 . . . . . (9), =e xX Annual range of temperature. From this we may calculate the secular range of temperature in the northern and southern hemispheres, with the following results :— 1881. ] Notes on Physical Geology. AT7 Northern Hemisphere. | Lat. N. peng Rane paeres Secular | Maximum* Secular ange. Range. 0 2-2 ¥F. 0-037 F. 0-185 F 10 45 ,, 0-075 ,, 0-375 ,, 20 13°2 ,, 0 -220 ,, 1:100 ,, 30 24°8 ,, OFAliS > 2-065 ,, 40 33-0 ,, 0 °550 ,, 2°750 ,, 50 AAD, 0-737 ,, 3-685 ,, 60 53 ,, 0-922 ,, 4610 ,, 70 59°8 0:997 ,, 4-985. ,, 80 ts) Lie 0-985 ,, Ze Pats a The secular range of mean annual temperature in the southern hemisphere is as follows :— Southern Hemisphere. Present Secular Maximum Secular Lat. 8S. Annual Range. Pompe Renee! 0 WT 0-037 F, 0-185 F. 10 7-0 ,, 0-117 ,, 0-585 ,, 20 LOSS, 5 O7E7by 5. 0 °875 ,, 30 13°3 ,, 0-222 ,, 1'110 ,, 40 11°8 ,, 0-197 ,, 0-985 ,, 50 Sion; 0-142 ,, O2TOss 60 GES); 0°108 ,, 0-540 ,, As extreme examples of the respective types of climate in the northern and southern hemispheres, I may give the result of my calcu- lations for North Grinnell Land and Kerguelen Island. | Tae Present Mean Maximum Secular ee Annual Temperature. Range. North Grinnell Land | 81 44. 2-42 F. 6°5 F. Kerguelen Island....| 50 OS. | +40°7 ,, OLO OE: | * Because the maximum eccentricity of the earth’s orbit is 4th instead of ,yth, as at present. 478 Action of an Intermittent Beam of Heat, $c. [Feb. 24. III. “ Further Experiments on the Action of an Intermittent Beam of Radiant Heat on Gaseous Matter. Thermometric Measurements.” By J. TYNDALL, F.R.S. Received Feb- ruary 21, 1881. | ; In the concluding paragraph of the note communicated on the 10th of January to the Royal Society these words occur :—‘‘ The vapours of all compound liquids will, 1 doubt not, be found sonorous in the inter- mittent beam.” Since that time I have examined eighty different liquids, both at the ordinary temperature of the air and at their boiling temperatures, and have verified so far the prediction just quoted. In all cases I have obtained musical sounds—some feeble, some moderate, and some exceedingly strong. I have, moreover, determined by ther- mometric expansion the absorptions exerted by the vapours of more than twenty of these liquids, and it is my intention to subject the whole of them to this test. The harmony and mutual support exhibited by two series of experiments, conducted in accordance with these two diverse methods, are on the whole admirable. The investigation, how- ever, is laborious, and many weeks must elapse before I am able to submit it in extenso to the Royal Society. Tested by the thermometric method, my old experiments on aqueous vapour again affirm their validity. A long and narrow glass tube, bent into the form of a \J, was partially filled with coloured water. One leg of the (J was connected with the recipient which contained the gaseous substances submitted to experiment, while the other end was left open to the air. Before permitting the beam to pass, the liquid stood at the same level in both legs of the tube. Cleansing the reci- pient thoroughly, and filling it with well-dried air, a powerful beam was sent through it. There was no sensible expansion and consequently no perceptible motion of the thermometric column. Air similarly dried was then passed over bibulous paper, moistened by water of a temperature of 14° C. The modicum of vapour carried forward at this temperature by the dried air, when smitten by the beam, produced instantly a depression of 55 millims. in the leg of the tube connected with the recipient, and an equal elevation in the other leg. The difference of level in the two legs amounted, therefore, to 110 millims. No trace of haze or sign of condensation could be detected within the recipient. Its boundaries were as bright, and its contents as free from turbidity, as when the dry air alone was employed. With a conical tube of a certain size, stopped at its base by a trans- parent plate of rocksalt, I have obtained a considerable intensification of the sounds. Abandoning the ear-tube altogether, and filling the 1881.] Presents. , 479 hollow cone with olefiant gas, its music has been heard at a distance of 18 feet from the source of sound. Presents, February 3, 1881. Transactions. London :—Statistical Society. Journal. Vol. XLIII. Part 4. 8vo. London 1880. The Society. Manchester:—Public Free Libraries. Report, 1878-79. 8vo. Manchester 1879. The Committee. Montpellier:—Académie des Sciences et Lettres. Mémoires, Sci- ences. Tome IX. Fasc. 3. Médecine. Tome V. Fasc. 2. Lettres. Tome VI. Fase. 4. 4to. Montpellier 1879-80. The Academy. Montreal :—McGill College. Annual Calendar, 1880-81. 8vo. Mon- treal 1880. The College. Naples :—Zoologische Station. Mittheilungen. Band II. Heft 2. 8vo. Leipzig 1880. The Station. Philadelphia :—American Philosophical Society. Proceedings. Vol. XVIII. No. 105. 8vo. 1880. The Society. Pisa :—Societa Toscana di Scienze Naturali. Processi Verbali. Nov., 1880. 8vo. The Society. St. Gallen:—Schweiz. Naturforschende Gesellschaft. Verhand- lungen. Jahresb. 1878-79. 8vo. St. Gallen 1879. 62e Réunion Générale. (1879.) 8vo. The Society. St. Louis:—Academy of Science. Transactions. Vol. IV. No. 1. Svo. St. Lows, Mo. 1880. The Academy. Missouri Historical Society. Publications. Nos. 1-4. 8vo. The Society. St. Petersburg :—K. Akademie der Wissenschaften. Repertorium fiir Meteorologie. Band VII. Heft 1. 4to. St. Petersburg 1880. The Academy. Tokio :—University. Calendar of the Departments of Law, Science, and Literature. 2539-40 (1879-80). 8vo. Tokio. Memoirs of the Science Department. Vol. I. Part.1. Vol. Il. 8vo. Tokio, Japan 2539 (1879). The President of the Departments. Observations and Reports. Washington : —Bureau of Navigation. American Ephemeris 1883. 8vo. Washington 1880. Astronomical Papers prepared for the use of the American Ephemeris. Vol. 1. Parts 2 and 3. 4to. Washington 1880. The Bureau. 480 Prosenes [Feb. 10, Observations, &c. (continued). United States Coast Survey. Report, 1876. Text and Prose Sketches. 4to. Washington 1879. The Surrey United States Geological Survey of the Territories. Report. Vol. XII. Fresh Water Rhizopods, by J. Leidy. 4to. Washing- ton 1879. Miscellaneous Publications, No. 12. North American Pinnipeds, by J. A. Allen. 8vo. Washington 1880. Bulletin. Vol. V. No. 4. 8vo. Washington 1880. The Survey. United States Naval Observatory. Subject-Index to the Publi- cations of the Observatory. 4to. Washington 1879. Catalogue of the Library. Part I. Astronomical Bibhography. 4to. Washington 1879. The Observatory. Wellington :—Colonial Museum and Geological Survey. Manual of the New Zealand Coleoptera. By Captain T. Broun. 8vo. Weilington 1880. Manual of the New Zealand Mollusca. By F. W. Hutton. 8vo. Wellington 1880. Fifteenth Annual Report on the Museum and Laboratory. 8vo. Wellington 1880. The Museum. Wiltshire :—Wiltshire Rainfall, 1879. 8vo. Marlborough 1880. Rev. T. A. Preston. Clausius (R.) Ueber die Anwendung des electrodynamischen Potentials zur Bestimmung der ponderomotorischen und electro- motorischen Krafte. 8vo. Bonn [1880]. The Author. Erichsen (John Eric), F.R.S. Address to the Royal Medical and Chirurgical Society. 8vo. London 1880. The Author. Hirst (T. Archer), F.R.S. On the Complexes generated by two Correlative Planes. 8vo. [1879.] The Author. Hull (Edward), F.R.S. On the Relations of the Carboniferous, Devonian, and Upper Silurian Rocks of the South of Ireland to those of North Devon. 4to. Dublin 1880. On the Geological Relations of the Rocks of the South of Ireland to those of North Devon and other British and Continental Districts. 8vo. | London 1880. | The Author. Presents, February 10, 1881. Transactions. Birmingham :—Philosophical Society. Proceedings, Vol. II. Part 1. 8vo. Birmingham 1880. The Society. Breslau :—Schlesische Gesellschaft. Jahres- Bericht, 1879. S8vo. Breslau 1880. The Society. 1881. ] Presents. 481 Transactions (continued). Brinn :—Naturforschender Verein. Verhandlungen. Band XVII. Svo. Brinn 1879. The Association. Venice:—R. Istituto Veneto. Memorie, Vol. XX. Parte 2, 3. Vol. XXI, Parte 1. 4to. Venezia 1878-80. Atti. Serie 5. Tomo IV. Disp. 10. Tomo V. Disp. 1-10. Tomo VI. Disp. 1-9. 8vo. Venezia 1877-80. The Institution. Vienna :—K. K. Geographische Gesellschaft. Mittheilungen, 1879. Band XXII. 8vo. Wien 1879. The Society. Wellington :—New Zealand Institute. Trans. and Proc. Vol. XII. Svo. Wellington 1880. The Society. Observations. Stonyhurst:—Observatory. Results of Meteorological and Mag- netical Observations, 1879. 8vo. Roehampton 1880. The Rev. 8. J. Perry, F.R.S. Sydney :—International Exhibition, 1879. New Zealand Court. Appendix to Official Catalogue. 8vo. Wellington 1880. The Commission. Observatory. Results of Rain and River Observations, 1879. 8vo. Sydney 1880. Results of Meteorological Observations, 1875. 8vo. Sydney 1880. The Government Astronomer. Turin :—Osservatorio della Regia Universita. Bolletino, 1879. oblong. Torino 1880. (2 copies.) Hffemeridi del Sole, della Luna, e dei Principali Pianeti, 1880-81. 8vo. Torino 1879-80. The Observatory. Upsala :—Observatoire de lUniversité. Bulletin Météorologique. Vols. VIII, IX. 4t0. Upsal 1877-78. The Observatory. Euclid. The Elements of Geometrie of the most auncient Philosopher Hvelide of Megara. Translated by H. Billingsley. Preface by M. I. Dee. 4to. London [1570]. R. Etheridge, F.R.S. Newton (Sir Isaac) Philosophie Naturalis Principia Mathematica. 4 vols. in 2. 8vo. Glasgue 1822. R. Etheridge, F.R.S. Reade (T. Mellard) The Glacial Beds of the Clyde and Forth. 8vo. Liverpool 1880. Oceans and Continents. 8vo. [London 1880]. The Author. Rosse (The Earl of) Observations of Nebule and Clusters of Stars made with the Six-foot and Three-foot Reflectors at Birr Castle, 1848-78. No. 3. 4to. Dublin 1880. The Author. Siemens (C. W.), F.R.S. The Dynamo-electric Current in its Appli- cation to Metallurgy, to Horticulture, and to Locomotion. 8vo. London [1880]. The Author. 482 Presents. [Feb. 17, Stone (H. J.) A Stereographic Projection, showing the Distribution of the Stars contained in the Cape Catalogue 1880, between 110° and 180° N.P.D. Single sheet. (2 copies.) The Author. Presents, February 17, 1881. ‘T'ransactions. Copenhagen :—Carolinska Medico-Chirurgiska Institutet. Fest- skrift. royal 8vo. Stockholm 1879. The Institute. K. Danske Videnskabernes Selskab. Oversigt. 1879, No. 3. 1880, No. 1. 8vo. Kjébenhavn. Skrifter. dte Rekke. Afd. 12, Bd. V. 4to. Kjdbenhavn 1880. The Academy. Danzig :—Naturforschende Gesellschaft. Festschrift. 8vo. Danzig 1880. The Society. Geneva :—Institut National Genevois. Bulletin. Tome XXIII. 8vo. Geneve 1880. The Institute. Halifax (Nova Scotia):—Nova Scotian Institute of Natural Science. Proceedings and Transactions. Vol. V. Part 2. 8vo. Halifaa (Nova Scotia) 1280. The Institute. Reports, Observations, &e. Birmingham :—Mason Science College. Calendar 1880-81. 8vo. Birmingham 1881. The Trustees. Caleutta :—Second Yarkand Mission. Scientific Results. Mammalia by W. T. Blanford. Lepidoptera by F. Moore. Rhyncota by W. L. Distant. Syringospheride by P. M. Duncan. 4to. Calcutta 1879. The India Office. Salford :—Museum, Libraries, and Parks Committtee. Annual Report, 1579-80. 8vo. Manchester. The Committee. Zi-ka-wei:—Observatory. Bulletin Mensuel. Jan. to Aug., 1880. Ato. On the Storms of the Chinese Seas, and On the Storm of the 19thand 20th March, 1880. By R. F. M. Dechevrens, 8.J. Ato. Zi-ka-wei 1880. The Observatory. Journals. Bulletino di Bibliografia e di Storia. Marzo, 1880. 4to. Roma. The Prince Boncompagni. Flora Batava. Afi. 251, 252. 4to. Leyden. : H.M. the King of the Netherlands. Indian Antiquary. Vol. IX. Part 113. 4to. Bombay 1880. The Editor. 1881.] Presents. A83 Creak (Staff-Commander EH. W.), R.N. Variation Chart of the World, 1880. The Author. Galloway (Robert L.) The Steam Engine and its Inventors. 8vo. London 1881. The Author. Jones (T. Rupert), F.R.S. On the Nature and Origin of Peat and Peat-bogs. 8vo. [1880]. On the Practical Advantages of Geo- logical Knowledge. 8vo. [1880. | The Author. Tennant (Col. J. F.), F.R.S. 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Calcutta 1880. Proceedings. 1880. Nos. 2-8. 8vo. Calcutta 1880. The Society. Cambridge (Mass.) :—Harvard College. Museum of Comparative Zodlogy. Memoirs. Vol. VI. No. 1. Vol. VII. No. 1 and No. 2. Part 1. 4to. Cambridge 1880. Bulletin. Vol. VI. Nos. 8-11. Vol. VII. No. 1. Vol. VIII. Nos. 1, 2. 8vo. Cambridge 1880. Annual Report of the Curator. 8vo. Cambridge 1880. Annual Reports of the President and Treasurer of Harvard College. 8vo. Cambridge 1881. The College. Cardiff :—Naturalists’ Society. Report and Transactions. Vol. XI. 8vo. London 1880. The Society. Jena :—Medicinisch-Naturwissenschaftliche Gesellschaft. Denk- schriften. Band I. Text and Atlas. 4to. Jena 1880. Jenaische Zeitschrift. Band XV. Heft 1. 8vo. Jena 1881. f The Society. 484 Presents. [Feb. 245 Transactions (continued). London :—Saint Bartholomew’s Hospital. Reports. Vol. XVI. 8vo. London 1880. The Hospital. Sanitary Institute. Report of the Fourth Congress: Exeter. 8vo. London 1880. The Institute. Observations and Reports. Mount Hamilton :—Report to the Trustees of the “ James Lick Trust”? of Observations made on Mount Hamilton. Ato. Chicago 1880. The Trustees. Vienna:—K. K. Central-Anstalt. Jabrbiticher. Jahrg. 1877-79. Ato. Wien 1880. The Office. Wellington :—Colonial Museum and Geological Survey. Paleeonto- logy of New Zealand. Part 4. 8vo. Weillington 1880. The Museum. Office of the Registrar-General. Statistics of the Colony of New Zealand. 1879. folio. Wellington 1880. The Registrar-General of New Zealand. Westminster :—Free Public Libraries. Annual Report, 1878-79. 8vo. Westminster 1880. The Commissioners. Presented by A. J. Ellis, F.R.S. :— Byrne (Oliver) Practical, short, and direct Method of Calculating the Logarithm of any given Number. 8vo. London 1849. Flower (Robert) The Radix, a new way of making Logarithms. London 1771. [MS. Transcribed from the Copy in the Graves Collection, University College, London. | Gardiner (William) Tables of Logarithms. 4to. London 1742. Hoppe (Reinhold) ‘Tafeln zur dreissigstelligen logarithmischen Rechnung. 8vo. Leipzig 1876. Houél (J.) Tables de Logarithmes a cing Décimales. 8vo. Paris S77. Koralek (Philippe) Méthode nouvelle pour calculer rapidement les Logarithmes. 8vo. Paris 1851. Leonelli ( ) Supplément Logarithmique. 2° Edition. 8vo. Paris 1876. | Namur (A.) ‘Tables de Logarithmes 4 douze Décimales. 8vo. Bruwelles et Paris. 1877. | Pineto (S.) Tables de Logarithmes Vulgaires a dix Décimales. Svo. St. Petersbourg 1871. Queipo (V. Vazquez) Tables de Logarithmes a six Décimales. 9° Hdition. 8vo. Paris 1876. 1881.] 485 Presented by A. J. Ellis, F.R.S. (continued) :— Schron (l.) Table d’Interpolation pour le Calcul des Parties Pro- portionelles, &c. 8vo. Paris 1873. Steinhauser (A.) Kurze Hilfstafel zur bequemen Berechnung finfzehnstelliger Logarithmen. 8vo. Wien 1865 Wace (Rev. Henry) On the Calculation of Logarithms. 8vo. [ London 1873. ] Last of Candidates for Election. March 3, 1881. THE PRESIDENT in the Chair. The Presents received were laid on the table, and thanks ordered for them. In pursuance of the Statutes, the names of Candidates recommended for election into the Society were read, as follows :— Alderson, Henry James, Col. R.A. Ayrton, Prof. William Edward. Bates, Henry Walter. Bristowe, John Syer, F.R.C.P. Browne, James Crichton, M.D., DL.D., F.R.S.E. Buchanan, George, M.D.,F.R.C.P. Christie, William Henry Mahoney, M.A., Sec. R.A.S. M.D., Clarke, Charles Baron, M.A., HES... BGS. Creak, Ettrick William, Staff- Commander, R.N. Dallas, William Sweetland, F.L.S. Darwin, Francis, M.A., M.B., aS: Day, Francis. Day, John, M.D. Dickie, Prof. George, A.M., M.D., BATS. Dobson, George Edward, Surgeon- Major, M.A., M.B., F.L.S. Douglass, James Nicholas,M.1.C.E. Foster, Prof. Balthazar Walter, F.R.C.P. VOL. XXXI. Glazebrook, Richard Tetley, M.A. Goodeve, Prof. Thomas Minchin, M.A. Grantham, Richard Boxall, F.G.S., M.1.C.E. Groves, Charles Edward, F.C.S. Herschel, Prof. Alexander Stewart. Hutchinson, Prof. Jonathan, F.R.C.S. Kempe, Alfred Bray, B.A. Lee, John Edward, F.S.A., F.G.S. Ley, Rev. W. Clement, M.A. Liversidge, Prof. Archibald, 1 (EeiS a oA Ca geal al Dts Macalister, Prof. Alexander, M.D., Sec. R.LA. McLeod, Prof. Herbert, F.I.C., F.C.S. Miller, Francis Bowyer, F.C.S. Niven, William Davidson, M.A. Ord, William Miller, M.D., F.L.S., F.R.C.P, Palgrave, Robert Henry Inglis, DSS ESy Phillips, John Arthur. Preece, William Henry, C.H. 2 M 486 Sir J. Conroy. | [Mar. 3, Pritchard, Urban, M.D., F.R.C.S. | Stoney, Bindon Blood, M.A. Radcliffe, Charles Bland, M.D., M.I.C.E. F.R.C.P. Tidy, Prof. Charles Meymott, Ransome, Arthur, M.A., M.D. M.B., M.R.C.S., L.8.A. Ranyard, Arthur Cowper, F.R.A.S. | Traquair, Ramsay H., M.D.: Rawlinson, Robert, C.B., M.I.C.E. | Warren, Charles, Lieut.-Col. R.E. Reinold, Prof. Arnold William, | Watson, Rev. Henry William, M.A. M.A. Williams, Charles Theodore, M.A., Rodwell, George F., F.R.A.S., 5D egal a Bs Cal Be F.C.S. | Wright, Charles R. Alder, D.Sc. Samuelson, Bernhard, M.I.C.E. Wright, Edward Perceval, M.A., Spiller, John, F.C.S. M.D., F.LS. The following Papers were read :— I. “Some Experiments on Metallic Reflexion. No. HI.” By Sir JOHN Conroy, Bart., M.A. Communicated by Professor STOKES, Sec. R.S. Received February 12, 1881. Professor Stokes did me the honour of communicating to the Royal Society a short paper (‘‘ Proc. Roy. Soc.,” vol. 28, p. 242) giving an account of some determinations I had made of the values of the prin- cipal incidence for, and the principal azimuth of, red hght, when reflected by a gold plate in contact with air, water, and carbon bisulphide. These experiments I have continued, using light of different refran- gibilities, and gold and silver plates, and also thin films of these metals. The observations were made by causing a beam of light which had been polarised elliptically, by passing through a nicol with its prin- cipal section at an angle of 45° with the plane of incidence, and a ‘quarter undulation plate,” with one of the neutral axes in that plane, to fall on the metal plate, and then altering the angle of incidence till the reflected light was plane polarised. The angle of incidence at which this was the case was different, according as one or other of the neutral axes of the quarter plate was in the plane of incidence, and the mean of these two values was taken as the true principal incidence. The goniometer used in these experiments was described in the former paper, but had an additional vertical divided circle attached to the inner end of the tube fixed to the collimator arm, in order to facilitate the adjustment of the quarter plate, and to permit the plate being changed, without the necessity of determining each time the position of the neutral axes. Brewster’s law, that the tangent of the angle of polarisation is equal 1881.] Some Experiments on Metallic [teflexion. 487 to the refractive index of the medium, not having been, as far as I was aware, ever experimentally verified in the case of transparent bodies in contact with media other than air, it appeared desirable to make some experiments on this point, though there was every reason for supposing that the law would be found to hold good. A crown glass prism was fastened to the vertical stage, the quarter undulation plate and the analysing nicol removed, the polarising nicol placed with its principal section in the plane of incidence, and the angle of polarisation determined, a paraffine lamp being used as the source of light. The thin glass vessel was then placed on the vertical stage, and filled successively with water and carbon tetrachloride, and the angles of polarisation again determined. Glass Prism. Peter nolanisation air.) 2. ee. 57 14 57 02 bea ss Widbelee a Marte ee es AD AL 49 43° carbon tetrachloride... 46 32 46 23 99 99 The angles of polarisation in air are the mean of twelve and four observations respectively, those in water of eight and twelve, and those in carbon tetrachloride of twelve observations. When the surface of the glass was in contact with water or carbon tetrachloride, its reflective power was so much diminished that it was not possible to determine the angle at which the minimum amount of light was reflected, and therefore the angles at which the light ceased to be visible were observed, and the mean of these taken as the angle of polarisation. The tangents of the angles of polarisation in water and carbon tetra- chloride, when multiplied by the refractive indices of these liquids, give the following values for the angle of polarisation in air :— | Angle of polarisation in air observed.......... 57 14 57 02 Angle of polarisation in air calculated from ob- MeGMIOMS LIT! WALED. . 0. soe os cleans se ete Oe 57 28 «57 33 Angle of polarisation in air calculated from ob- servations in carbon tetrachloride.......... ov, Ol, Soran The distilled water which was used in these experiments had not been freed from air, and this may account for the values of the angles of polarisation in air, calculated from the measurements made in water, being somewhat too high. These observations show that, within the limits of experimental error, Brewster’s law holds good for glass in contact with water and carbon tetrachloride, as well as air, and that in all probability it is universally true for transparent bodies. 2m 2 488 Sir J. Conroy. 7 [ Mar. 3, The same gold plate which had been used in the previously de- scribed experiments was fastened to the stage of the goniometer, and the principal incidences and azimuths observed with yellow and blue light, when the plate was in air, water, and carbon bisulphide. An alcohol flame with a salted wick and a paraffine lamp, with a glass trough filled with ammonio-sulphate of copper placed in front of it, were used as the sources of hight. The light transmitted by the deep red glass used in the previous experiments and by the ammonio- sulphate was not homogeneous. The light of the greatest intensity in the one case was slightly more refrangible than C, and in the other of a refrangibility nearly midway between F' and G. j The polarising nicol was placed with its principal section at an angle of 45° with the plane of incidence in each of the four quadrants successively, and two observations made with the nicol in each posi- tion ; so that the value of the principal incidence and the principal azimuth for each position of the “ quarter undulation plate” is the mean of eight observations. The iollgnie table contains the results of these experiments ; the values for red light, which had been previously obtained, are included in it for the sake of comparison :— Quarter plate. Quarter plate. Corrected if Vat: numbers. Pal. AY. Pale Ae PA P.A. iets Plate atvA. | 80) 137) 435 52 =cSe0s = poor Piokd inate, | Ba atB. 7045 3557 73 45 35 21 redlight. (Meanvalue 7529 3554 7554 8532 760 35 27 ea! Plateat A. 7633 3812 7359 36 27 Gold in air, Plate at B. 68 33 37 39 72 5d 36° 20 Meanvalue 72 33 37 55-- 73 27 36 23 73°28) 40.22 Plate at A. 65 32 30 19 60 27 32 ol Plateat B. 6903 2944 71 51 32 09 Meanvalue 6717 3001 6609 38220 67 24 29 47 yellow light. Gold in air, blue light. Plate at A. 7646 37 13 74 46 86 0 Plate at B. 6646 3550 7025 £36 49 Meanvalue 7146 3631 7235 38624 7246 36 23 Plate at A. 73 47 3805. 7005 37 28 Plate at B. 65 29 88 27 6851 36 22 Mean value 69 38 38816 6928 3655 69 28 36 52 Plate at A. 6151 28 30 5709 31 35 Plate at B. 65 26 2906 7059 3101 Meanvalue 63 88 2848 6404 3118 63 36 28 38 red light. Gold in water, yellow light. Gold in water, blue light. | Gold in water, } 1881.] Some Experiments on Metathe Reflexion. 489 Quarter plate. Quarter plate. Corrected ie AYalig numbers. Bale 12 uN pale PAG Pal pee ° 4 ° 4 bisulphide, + Plateat B. 62 44 38740 68 26 36 43 ° / fe) / fe) é ° 4 Gold in ide | Pat fin dk, CG, Oe) Bil AAS yl BY | RG SE) red light. Meanvalue 69 27 3744 7001 3651 7003 36 48 bisulphide, 4 Plateat B. 6150 38 24 6602 37 10 Gold in carbon {vit at As Gl LO) 3909) 67 02) 937 17 yellow light. LMeanvalue 66 25 388 46 6632 38713 6632 37 12 bisulphide, < Plateat B. 61 30 3313 67 56 31 08 blue light. Meanvalue 6040 3221 6110 3012 6040 32 23 Gold in hid, Pa at A. 5951 3130 5424 2917 The last column gives the values as corrected by Professor Stokes’ method (loc. cit., p. 248). The table shows, that for red and yellow light the observations made with plate I, and for blue light those made with plate VI, are but of little value; whilst for red and yellow light the observations made with plate VI, and for blue light those made with plate I, lie very close to the corrected numbers. All subsequent experiments were therefore made with plate VI for red and yellow light, and with plate I for blue light. The gold plate used in these experiments had been polished with rouge, and from time to time rubbed with a little rouge, and then with a clean chamois leather to remove the polishing powder. From some experiments with a silver plate, it appeared probable that the optical constants of the plate might depend to a certain extent on the nature of the polishing powder used, and therefore the gold plate was dismounted and polished with putty powder, and then well rubbed with a clean chamois leather, and the principal incidences and azimuths determined. Four observations were determined in each position of the quarter plate, two with the principal section of the polarising nicol on the right, and two on the left of the plane of incidence; the plate VI being used with red and yellow light, and plate 1 with blue ght. Red. light. Yellow light. Blue light. PA 12 ashe PL. PeAG PI. PA. Gold plate in alr. Plate at B. 7145 41 29 7121 4057 6634 34 55 fo} / fo} / fo) / fo) / (o) 4 fo} / {. at A. » 75: 57 Aeo7 72 18 41 40 67 38 384 44, Meanvalue 73 51 41 23 7149 4118 6706 £34 49 After an interval of two months the measurements were repeated, the plate being first rubbed with a clean chamois leather. 490 Red light. iPr IPA. fo) / o} / teeinis Plate at A. 76 20 42 40 pe ebiate an | Pht at B. 71 49 42 05 te Mean value 7404 42 22 Sir J. Conroy. Yellow light. Pal eRe 7216 Al 07 7059 41 14 71 38 41 10 [ Mar. 3, Blue light. PT: P.A. 67 59 37 12 66 29 35 50 67 14) 336r3h The measurements were then made with the plate in water and carbon bisulphide. Red light. Yellow light. Blue light. PAL P.A. P.I. P.A. Pi. « see See Plate at A. 7243 4236 6923 4210 6350 36 44 eee L )ziateat B. 6807 42.89 6728 4101 6239 35 12 water. “ (Meanvalue 7025 4287 6825 4135 6314 35 58 eae Plateat A. 7317 4210 6711 3925 6427 36 07 pate ae Plateat B. 6818 42 24 6636 4225 6225 36 41 waner- 11. | Meanwalue 70 24 49 17° 6653. 400551) s6sGmeeGEed Gold platein ;-Plateat A. 7152 4287 6658 4126 6141 36 19 carbon | Pit at B. 6657 4229 6614 41-56 58 29 37°35 bisulphide. Mean value 69 24 4233 6636 4141 6005 36 57 The mean values of these two series of determinations are— Gioloisiniaimaneds cs cusete ee » water. eucar bom bisulphide. . Red light. Pale P.A. 73 57 = =41 52 70 24 42 27 69 24 42 33 Yellow light. Pi PA. ° / O° / 7143 41 14 67 39 «41 15 66 36 «041 41 Blue light. Pa Poa te) / ie) / 67 10 35 40 63 20 36 11 60 05 36 57 The values of the principal azimuths are considerably higher (about 6°) than those previously observed; and in the case of red and yellow light, when the gold plate was in air or water the principal incidences are lower (about 2°) than with the plate polished with rouge; but with blue light, and also when the plate was in contact with carbon bisulphide, there was but little difference in the values of the principal invidences. The plate was again cleaned with rouge, and the measurements in air repeated. Red light. Yellow light. Blue light. Pan P.A. IPATE P.A, Pale PAC ie} / O° / io} tA .¢] f ° é ce) ‘4 Plate at A. 76 41 41 07 Gold in air. } Plate at B. 7205 41 16 Mean value 74 26 41 11 Plate at A. 76 31 4047 7246 4039 6907 . 3444 Gold in air. | Pit at B. 72 11° 40°15 72-06. 39°40 9267 55.9 seu0s Mean value 74 21 4031 7226 4009 68 31 38 54 1881. ] Some Haperiments on Metallic Reflexion. AS] Polishing the plate with rouge appears to have had the effect of increasing the values of the principal incidences and diminishing those of the azimuths, but not to such an extent as might have been antici- pated from the difference between the values obtained with the plate before and after it had been polished with putty powder. This may be due to the original smoothing and polishing with rouge having altered the surface of the plate to a greater extent than could be effected by repolishing with rouge the already polished plate. The gold plate, which was a long narrow one, having been con- stantly rubbed in one direction whilst being polished, it was thought possible that the direction of the furrows produced by the polishing might influence the result: the plate was therefore turned so that these were perpendicular to the plane of incidence, instead of parallel with it. This alteration in the position of the plate did not appear to alter the value of the constants. Red light. Pale Pov. Pilatevat As. se: 76 42 4.0) 4.4. Gold in air 1 Phi Bitillaessteses TS DE 39 54 Mean value..... 74 32 40 19 In order to obtain a gold surface free from the influence of any polishing powder, a sheet of gold leaf was placed between two pieces of paper, and the paper and gold cut into strips with a sharp pair of scissors, the gold leaf transferred to glass slips, floated out with water, in the manner described by Faraday, and the water allowed to drain off, leaving the gold leaf stretched out on the glass. Some of the pieces of gold leaf were thinned by being floated on a dilute solution of potassium cyanide, the cyanide solution washed away with water as soon as the thickness of the gold had been sufhi- ciently reduced, and the gold leaf left adhering to the glass. Gold leaf treated in this way has a very fairly smooth surtieet sufficiently good to act as a tolerable mirror, and both the ordinary leaf, and that thinned by the action of potassium cyanide, is trans- parent, the transmitted light being, as is well known, green. In order to determine the thickness of the gold, the glass slips were carefully cleaned and weighed before the gold was transferred to them, and then, after being dried, again weighed. The area of the gold was measured, and the specific gravity being taken as 19°36 (“‘ Watts’ Dictionary,’’ vol. ii, p. 926), the thickness calculated. The average thickness of gold leaf is stated in “ Watts’ Dictionary ”’ (Joc. cit.) not to exceed 55,4. of an inch (‘0001270 millim.), and in 200000 “* Roscoe and Schorlemmer’s Chemistry ” to be about ‘0001 millim., 492 Sir J. Conroy. [Mar. 3, numbers that agree very fairly well with those determined in the above-mentioned manner, especially when the actual weight of the gold (in no case exceeding ‘0029 grm.) and the uncertainty as to its true specific gravity in the state of gold leaf is taken into account. The glass slips were fastened to the goniometer, and the constants determined for the gold-air surface; four observations being made in each position of the quarter plate, two with the principal section of the polarising nicol on the right, and two on the left, of the plane of incidence ; the plate VI being used with red and yellow light, and plate I with blue light. No. of film. Thickness. a es 0 -0000645 millim. sad cope aes ee 0 0000709 Dag Sa a ee () 0000837 AED, A So fem | 0 -0001107 SOE 2 Pint ra GF 0 0001135 oo E ox NT bo Red light. Yellow light. Blue light. Pe 1 Reale Hale PAS deaf PEAS O° / ° / fo} / fo) / Oo é/ ° / Plate at A. 74 43 40 5 44. 05 40 51 68 18 37 2 No. 2 Plate at B. 70 39 4] 14 69 26 40 11 65 54 37 02 Mean value 72 41 4102 7015 40382 - 676633570 Plate at A. 7516 40 42 W232, 40 10 68 56 35) 1 No. 7. Plate at B. 71 48 40 26 70 45 40 21 66 20 35 36 Mean value 73 32 40 34 71 38 40 15 67 38 Be) Plate at A. 76 44 43 27 73 59 41 45 69 51 38 30 No. 5. | Plt RIB 72) Bh 43 30 72 Ad 42 22 67, 5! 38 16 Mean value 7451 43 28 73 20 4203 6851 £38 23 Plate at A. 76 27 43 32 73 06 42 39 69 54 388 59 No. 4. | Plate ate. mieo9 42 42 Fy eR: 42, 21 67 21 38 52 «Mean value 74 33 4307 7214 42830 68 37 38 55 Plate at A. 76 34 42, 56 73 20 42 O02 69 49 39 09 No. 3. J Bit abe 222A 72 16 4l 59 67 16 38 31 Mean value 7428 4255 7248 42 0 68 32 £38 459 Numbers 2 and 7 had been thinned with potassium cyanide, the other three (3, 4, and 5, being all cut from different leaves) were of | their original thickness. The. table shows that, as the thickness of the leaf increases, the principal incidence and the principal azimuth increase, and to about the same amount for all three kinds of light, although only portions of the same leaf appear to be strictly comparable with each other. The values obtained with the gold leaf and with the gold plate cleaned with putty powder agree fairly well together; the principal 1881.] Some Experiments on Metallic Reflexion. 493 incidences and azimuths being somewhat higher, especially with blue light, in the case of the gold leaf. It therefore appears probable that of the two sets of values for the gold plate, those obtained after the plate had been polished with putty powder are nearest the truth. A large number of determinations of the principal incidences and principal azimuths were made with a silver plate in air, water, and carbon tetrachloride, with both the quarter undulation plates. The silver plate had been polished with rouge, and during the course of these experiments, which were carried on at intervals during some months, rubbed with a little rouge from time to time, and although afterwards well rubbed on a clean chamois leather, in certain hghts it appeared to have a reddish tinge, although the surface was most brilliant. In some few of the earlier experiments sixteen observations were made in each position of the quarter plate, four with the polariser in each quadrant; but most of the numbers are the means of eight observations, two for each position of the polariser. The following table contains the measurements made with the quarter plate V1 for red and yellow light, and with quarter plate I for blue light :— Red light. Yellow light. Blue light. Pit, PAG Pare pe AY, alle Dose oO / fe} / [o) / fo} / [o) / fo} / st Plateat A. 7813 3250 7606 3540 7006 38 43 ver in air. Plate at B. 7504 3158 75 40 3544 7316 39 26 Meantyalue “76°38 32°25 75 53° 35°42 7 4 39702 "5 42 3510 7216 88 45 se Mee Pits at. B 70. 32 47 5 21 : 34.50 172 24 -38 46 Meanvalue™ 75 5b 32 54° 975 31 985 04 72°20 > 3845 {rin ate De Sas Ol Bltoneae 71s $342. 7B 1 36 4767 09 4onos Silver In Plate at B. 7116 3312 7220 3527 6908 40 07 NE Meanvalue 7314 3327 7245 3607 6808 4006 Silver in RiateahA. 7 04 32°52" 70 2 35 41 6432 £389 36 Pen. | Bi at B. 7101 3234 7050 85 22 6732 39 10 tetrachloride. \.Meanvalue 73 02 3243 7088 35 81 6602 89 23 The values of the principal incidences and principal azimuths were also determined by a somewhat different method. The principal section of the polarising nicol was placed successively in the plane of incidence, and at right angles to it, and the neutral axes of the quarter undulation plate (plate VI being used) at an angle of 45° with this plane. The angle of incidence, and the azimuth of the analysing nicol by AO4 Sir J. Conroy. [ Mar. 3, which the ight was reduced to a minimum, were observed ; two such observations were made, and then the quarter plate turned through an angle of 90° and two more observations made, so that the values for each position of the polarising nicol are the means of four observations. The retardation produced by the plate not being equal to 90° for the wave-length of the light employed, the resultant beam was ellipticaily polarised, the major and minor axes of the ellipse being in the plane of incidence, and in the plane perpendicular to it, or vice versa. The relative position of the axes depending on the position of the polarising nico]; and on the amount of retardation produced by the plate (we., whether it was less or more than 90°). An elliptical vibration being equivalent to two rectilinear vibrations in the planes of the axes, differmg in phase by a quarter of an undu- lation, and of different amplitudes, this method affords a ready means of producing with the same retarding plate a difference of phase of exactly 90° between the vibrations in the plane of incidence and the plane perpendicular to it with light of different wave-lengths. Hence the angle at which light polarised in this manner is reflected by a metallic plate as plane polarised ight is the true angle of principal incidence; the azimuth, however, of the reflected lhght is not the principal azimuth. The azimuths are different, both in sign and in amount, for the two positions of the polarising nicol, according as the major or the minor axis of the ellipse is in the plane of incidence, the vibration in the plane of incidence being the one retarded and reduced in amplitude by the act of reflexion. The ratio of the semi-axes of the ellipse being called y, and the observed azimuths a, and ay, the ratio of the amplitudes of the vibra- tions in the plane of, and perpendicular to, the plane of incidence after reflexion by the metallic plate (the amplitudes in the incident beam being equal), or, in other words, the principal azimuth 6, is determined by the equations— tan a= ah ; a which give tan a, tan a,=6". The table contains the determinations made in this way with the silver plate in air, water, and carbon tetrachloride; the position of the principal section of the polarising nicol, with reference to the plane of incidence, being stated in the first column, and the mean values of the principal incidences, and the values of the principal azimuths, caleu- lated by the above-mentioned formula, in the last line of each portion of the table— 1881.] Some Experiments on Metallic Reflexion. 495 Red light. Yellow light. Blue light. Pt. AS Pal A. PAL \. ° / ° / ° / fo} / te) / ° / pll. 76 03 36 11 75 20 35 52 72 07 31 44 ppd: 76 19 29 26 75 35 35 30 72 32 47 38 Silver in air. fon ut: 32 43 75 27 35 41 72 19 39 28 Silver in pll. 7358 38734 7256 8684 6948 31 14 water. ppd. 7403 3057 7313 8552 6959 48 14 74 01 34 11 73 05 36 13 69 53 39 29 Silver incarbon f pl. 73 04 38 50 72 59 37 48 68 49 31 44 tetrachloride. Lppd. 73 09 31 17 72 38 37 07 68 19 49 44 73 07 34 58 72 47 37 27 68 34 40 30 The azimuths for silver in air and water with yellow light were so close to one another, that the mean was taken in these two cases as the principal azimuth. The determinations of the reflexion constants of the silver plate made by the two different methods agree fairly well together, but are not in accordance with subsequent observations made with films of chemically deposited silver, or with M. Jamin’s experiments (‘‘ Cours de Physique,” edit. 1866, vol. 111, p. 693), the principal incidences being somewhat too high, and the principal azimuths having different values for hght of different refrangibilities, instead of being nearly the same for all kinds of hght. The plate having been polished with rouge, and haying, as has already been mentioned, a reddish tinge, due in all probability to minute particles of the powder having become embedded in its surface, it appeared possible that the difference in the values of the azimuths for the three kinds of light might be due to the rouge; the piate was therefore dismounted and well polished with putty powder, which was chosen as being nearly white, and then the measurements repeated in the usual manner. Red light. Yellow light. Blue light. PAT: IPeA: 1 | eae) ah: = Pale BeAS ° / ° / ° / re) / ° / / Plate at A. 78 26 4402 75 O 4411 71 28 42 56 Silver in air. | Pt at B. 7433 43 41 7414 4316 7139 £43 04 Mean value 76 29 43 51 7437 43 22 7133 43 O oo PlateatA. 7618 4427 7238 4454 6715 43 10 ilves im Plate at B. 7137 4346 7122 4320 6823 43 05 water. I. (Mean value 7357 4406 72 0 4407 6749 48 07 neat Plate at A. 7553 4359 7302 4437 6627 43 51 phen Plate at B. 7153 4359 7159 4346 6742 48 41 water. IT. Mean value 73 53 4359 7230 4411 6704 43 46 496 Sir J. Conroy. [Mar. 3, Red light. Yellow light. Blue light. Pop PAR Po. PA. Pek. iPeAS fo) / ro) / / fe) / re) / Silver in Plate at A. 7409 4426 7205 4831 65 20 45 25 carbon st Plt at B. 70480" 44°12 7) 12" 43°09) G7 sso chloride. I. LMeanvalue 72 26 4419 7138 43 20 6626 44 23 Silver in f Plate at A. 975 Wil 44. 34 72,13 43 56 67 10 45 44 carbon tetra- 4 Plate at B. 70 386 4409 7110 4405 6751 £48 37 chloride. II. \.Meanvalue 72 53 44 21- 7141 44 0 6730 44 40 Mean value. Silver in air. "6 29 AS) bik 74. 37 43 22 71 33> 423 Silver in water. VIB) IE 44, 02 72 A 44, 09 67 26 43 26 Silver in carbon tetrachloride. 72 39 4420 713839 4340 6658 44 81 The values of the principal incidences are nearly the same as when the plate had been cleaned with rouge, but the principal azimuths, in addition to being considerably higher, differ but little for the three kinds of light instead of increasing with the refrangibility of the hght. Films of silver chemically deposited on glass were prepared by Martin’s process (“‘ Ann. de Chimie,” 4th Series, vol. xv, p. 94). Glass slips, similar to those used for mounting microscopic objects, were well cleaned, polished with rouge, washed with water, a little nitric acid poured over them, and then again washed and dried. A rectangular frame (about 15 centims. by 7 centims.), formed of two glass rods, the ends of which were fixed into pieces of wood, was placed in a shallow earthenware dish partly filled with distilled water ; the surfaces of the pieces of glass which were to be silvered were wetted with a mixture of equal parts of alcohol and potassium hydrate solu- tion, and then the glass slips placed with their ends resting on the glass rods, and with their wetted surfaces downwards. There was just sufficient water in the dish for the lower surfaces of the glass slips to be in contact with it, whilst the upper remained dry. The silvering solutions were mixed in another dish, care being taken that the depth of the silvering solution was the same as that of the water, and the frame with the slips resting on it, transferred from one dish to the other. The room in which the silvering was carried on being very cold the action was slow, and till at least five minutes had elapsed there was hardly any deposit; the slips were removed successively after 8, 1], 14, and 18 minutes, well washed with water, and placed on edge to dry. The reflexion constants in air, water, and carbon tetrachloride were observed, and then after the area of the silver had been measured, and the slips dried and weighed, the silver was rubbed off with a damp cloth, and the glass again dried and weighed, and from the loss of weight and the area, the thickness of the films calcuiated. The 1881.] Some Laperiments on Metallic Reflexion. A97 density of the silver being taken ay 10°62, that being the value for silver, finally divided by precipitation, given in ‘‘ Watts’ Dictionary,” Vol. Pp. 277. Thickness. Film I, removed after 8 minutes, () ‘00004035 miilim. ee L, a Se ie | by 0 00006848 —_,, + val a ee eee A - 0-000077 72, aL “5 aon MS 5 0) 0000399 aar These values for the thickness of the silver films agree fairly well, being of the same order, with those determined by Quincke (“ Pogg. Ann.,”’ vol. exxix, p. 177), who found that similar films varied from 00000089 millim. to 0°000075 millim. Silver films in air. Red light. Yellow light. Blue light. P.I. eats PA P.A. lle ev AG xe) / (oe) / (o) / rn) / (o) / fo) / Plate at A. 7255 30 14 68 57 28 24 66 30 31 02 Lig Plate at B. 68 35 30 02 68 31 26 32 66 29 30 54 Mean value 70 45 30 08 68 44 27 28 66 30 30 58 { Plate at A. 73°39 40 16 LOr23 39 26 66 56 40 31 II. Plate at B. 69 03 39 39 69 36 38 05 66 43 38 39 Mean value 71 2) 38957 6959 38 45 6649 £89 35 Plate at A. 74 04: 41 25 70 53 42 05 66 40 40 55 1B Plate at B. 69 42 41 10 70 01 41 39 67 17 40 15 Mean value (aso TA Ore ie Ale 52 iGo 5S eA0no> Plate at A. 74 32 Al 21 He LO Ale S9 66 36 40 35 EV. Plate at B. 69 35 41 08 "0 37 41 17 67 19 41 © Mean value 72, 03 41 14 70 48 41 28 66 57 40 47 Silver films in water. Red light. Yellow light. Blue light. Par TRANS P.I. PAN Pale IPS Ae Plate at A. 69 53 29 32 67 07 33 25 61 39 33 44 ii | Pla at B. 66 42 38l 09 67 08 34 40 63 32 34 20 Mean value 6817 3020 6708 3401 6235 £34 02 Plate at A. 70 22 39 34 66 56 89 07 62 30 389 O1 ee | Pt at B. 65 41 39 05 66 47 88 44: 62 43 39 14 Mean value 68 01 3919 6651 38855 6236 £389 07 Plate at A. 69 37 4127 6606 4059 62 0 389 09 S0b Plate at B. 65 13 AN IL 66 02 40 24 62 32 388 42 Mean value 67 25 41 19 66 04 40 41 62 16 38 55d Plate at A. 70 384 41 02 66 41 41 O1 62 44 39 12 IV. Plate at B. 65 23 40 26 66 O 41 11 63 12 39 14 Mean value 67 58 4044 6620 4106 6258 #=3918 A98 Sir J. Conroy. (Mewes Silver films in carbon tetrachloride. Red light. Yellow light. Blue light. Pale P.A. P.I. P.A. Pale P.A. fe) {e) / o) / fo) 4 ° 7 fe) 4 Plate at A. 69 20 385 30 3665 59 38419 60 55 384 5 I. | Ps at B. 65 13 33 24 64 20 34 54. 61 31 34 40 Mean value 6716 38427 6519 8436 6113 34 49 Plate at A. 69 38 3951 6629 3849 6149 #£87 54 II. Plate at B. 64 30 88 59) 65 20 937-25 62 13 388 14 Mean value 67 04 38925 6554 38807 6201 £38 04 Plate at A. 68 21 40 42 - 6430 3912 60 26 37 39 III. Plate at B. 63 20 40 22 £464 09 4014 6057 88 22 Mean value 65 50 40 32 64 19 39 43 #60 41 38 0 Plate at A. 68 54 41 20. 65 05 40 G 61 05 38 21 IV. Plate at B. 63 56 40 24 6446 39 45 61 46 40 50 Mean value 66 25 4052 6455 39 52 6125 #39 35 Five similar glass slips were silvered in the same manner, being removed from the silvering solution after 7, 10,13, 16, and 19 minutes, and the reflexion constants for air determined. The thickness of the films was not ascertained, as they were required for some other experi- ments, and were therefore kept. Silver films in air. Red light. Yellow light. Blue light. P.I. P.A. Bad P.A. P.I. Peas 4 f / te) ° ° ° fo) 4 te} f Plate at A. 73 0 3025 69 387 38132 6648 33 11 V. | Pit at B. 68 27 28 10 70 02 30 52 66 24 3217 Mean value 7043 2917 6949 8112 66 386 32 44 Plate at A. 73 18 3710 6950 88 07 66 42 38 29 WAL | Bt at B. 68 39 387 36 68 47 3\7/ SIL 66 04 387 35 Mean value 7058 38723 6918 38749 66 23 £38 02 Plate at A. 74 06 41 24 7049 4114 #4267 32 40 0O VI. | at B. 69 53 4049 7010 4047 6632 £40 04 Mean value 72 0 4106 7030 41 O 6702 £40 02 Plate at A. 74 43 41 20 W125" 4 54) Gea 41 02 VIII. {Bae at B. 70 18 Al 25 70 51 40 24 6656 £40 52 Mean value 72,28 . 41-22 71 08 41 09 67 18 40 57 Plate at A. 75 21 4220 7147 =42 24 6636 £42 09 IDG | Bit at B. 7042 4232 7047 4219 6725 41 62 Mean value 73 O1 A2 26 Ab ers yA) PAL 67 O 41 O 1881. | Some Haxpermments on Metallic Reflexion. 499) The table for the silver film in air shows that with the increase of the thickness of the film the principal incidence increases for all three kinds of light, but the increase is greatest with red and least with blue light. ‘The principal azimuth also increases with the thickness, but does so more rapidly, the difference between the values for films I and II and between V and VI being very considerable, whilst the values for films IT, III, and IV and VII, VIII, and IX lie close together, With films II, V, and VI the azimuths increase from red to blue, whilst with the thicker films they decrease; film I, however, furnishes an exception, for, although very thin, the azimuths decrease from red to blue. In this respect the thicker films behave like the silver plate cleaned with putty powder (p. 496), and the actual values of the azimuths in both cases are about the same; the principal incidences, however, are much lower with the films than with the plate. The difference in the values of the principal incidences may possibly be due to the effect produced on the plate by the pressure necessary to polish it. When the films were in water and carbon tetrachloride, the prin- cipal incidences decreased to a slight extent with the increased thickness, but the variation was small in amount. The azimuths in the case of film I in water increased from red to blue, but in carbon tetrachloride, and with the other films in both liquids, the azimuths decreased from red to blue. When the films were in contact with the liquids, the principal inci- dences were lower, except with film I, than in air, and the principal azimuths were also lower, instead of being higher, as had been the case with the gold and silver plates. , Quincke (“‘ Pogg. Ann.,” vol. cxxix, p.177) made a large number of observations with silver films and red light, and found that the values of the principal incidences increased with the thickness, and tended to a constant value, and also that as soon as the thickness of the metal exceeded 0°00002 millim. there was but little further change in the valiie of the principal incidence. In the short paper which appeared in the ‘‘Proc. Roy. Soc.,” vol, 28, p. 242, it is stated that the numbers obtained by multiplying the tangents of the angles of principal incidence for red light and the gold plate in water and carbon bisulphide, by the refractive indices of these media, were somewhat higher than the tangents of the angles of principal incidence for air: This isalso the case for the determinations made with the gold plate and yellow and blue light, and for those made with gold leaf, the silver plate, and the silver films with all three kinds of light. Thus for the silver plate cleaned with putty powder the values are as follow :— 500 Sir J. Conroy. | Mar. 3, Red light. Yellow light. Blue light. Principal incidence in air observed 76 29 74 37 71 33 Calculated from observations made AM Water gc sau eee ee Gan wee 71 Ad 76 30 72 46 Caleulated from observations made in carbon tetrachloride........ 77 54 Ze Us (a 62 In the case of the silver films the difference between the observed and calculated values is greatest with the thinner films (amounting to nearly 4° for the thinnest, with red light) and diminishes as the films increase in thickness. The values for the refractive index for gold were also calculated by the formula given by Lundquist (“‘ Poge. Ann.,” vol. clii, p. 405), n?, = tan?A(1—sin?A.sin?20), and the values for the relative indices for water and carbon bisulphide multiplied by the refractive indices of these media, but the numbers thus obtained did not agree with those deduced from observations of the principal incidence and azimuth in air. These experiments appear to show, first, that with glass in contact with media other than air, the tangent of the angle of polarisation is equal to the relative refractive index of the media. Second, that the optical constants of a polished metallic plate depend, to a certain extent, on the substance with which it has been polished, and that this surface condition is a fairly permanent one, not being destroyed by contact with liquids or by a considerable amount of rubbing with a clean chamois leather. Third, that when the plate is in contact with media other than air, the principal indices are lower, and the principal azimuths higher than in air; but that there is no simple relationship discoverable between the change in the values of the constants and the indices of the media. Fourth, that with metallic films the principal incidence and the prin- cipal azimuth increase with the thickness of the film, and that therefore more than one layer of molecules is concerned in the act of reflexion. The fact that with the increase of the thickness of the films the principal azimuth increases appears to show that the surface layers reflect light polarised in the plane of incidence more abundantly than light polarised perpendicularly to that plane, and that as the number of reflecting layers increases, the amount of light polarised perpendicu- larly to the plane of incidence which is reflected increases also ; or, in other words, the light polarised perpendicularly to the plane of inci- dence penetrates to a greater depth than that polarised in the plane of incidence. 1881.] Dr.G. Thin. On the Trichophyton tonsurans. 501 Il. “On the Trichophyton tonsurans (the Fungus of Ringworm).” By Gerorce Tun, M.D. Communicated by Professor Huxuey, Sec. R.S. Received February 19, 1881.* (Abstract. ) When hairs affected with the Trichophyton tonsurans are cultivated in cells, the development of the spores on the sides of the hairs can, if it occurs, be observed in situ under the microscope. When the attempted cultivation takes place on the surface of a fluid in a test-glass, it is also possible, after maceration in solutions of potash, to decide whether the spores in the hairs have grown out from the surface of the hair, and to distinguish between a growth of adventitious fungi and the erowth of the Trichophyton. The paper gives an account of experiments made by the use of cells and test-glasses, which were kept at a temperature of between 92° and 98° F., but in a few instances at the ordinary room temperature. The Trichophyton remained sterile in cultivations attempted with a solu- tion of phosphate of soda and tartrate of ammonia, with Cohn’s fluid, milk, carrot infusion, turnip infusion, salt solution (0°75 per cent.), ege albumen, egg albumen and potash, and vitreous humour and potash. The only method by which it was grown was by moistening the hairs with vitreous humour. When moistened with vitreous humour, the spores on the sides of the hairs placed in cells were seen to grow into a mycelium, and free growth took place when the hairs were floated on the surface of this fluid in test-tubes. It did not grow in cells when the hairs were immersed in a large drop, nor in test- tubes when the hairs were kept at the bottom of the tube. The growth observed consisted in a formation of mycelium, which sprouted from the spores in the hairs, and in the formation of spores in the newly-formed mycelium. The successful cultivations were, with one exception, at the incubator temperature. In the exceptional instance the fungus grew at room temperature, but more feebly and slowly than at the incubator temperature. It was shown by experiments in which Aspergillus, Penicillium glaucum, and other fungi grew around the hairs, whilst the spores of the Trichophyton remained sterile, that the latter is essentially distinct from the common fungi whose spores are present in the atmosphere. The development of the spores by the only method found successful could not be relied on as certain in any given case. It was not found * ‘Towards the expenses of this research a grant was made by the British Medical Association on the recommendation of the Scientific Grants Committee of the Asso- ciation. VOL, KXXT. 2N 502 Dr. G. Thin. On Bacterium decalvans. [ Mar. 3, successful in hairs that had been kept for a period of weeks folded in paper, nor in nineteen cultivations attempted with hairs taken from patients under treatment. ‘The negative value of these latter experi- ments is diminished by the occasional failure with hairs freshly extracted from untreated cases. The fact that the spores of the Trichophyton will not grow when immersed in vitreous humour, whilst they do grow when only moist- ened by it, explains why inflammatory exudation from the blood- vessels cures ringworm of the scalp. Ill. “On Bacterium decalvans: an Organism associated with the Destruction of the Hair in Alopecia areata.” By GEORGE Turn, M.D. Communicated by Professor HUXLEY, Sec. B.S. Received February 19, 1881. (Abstract. ) The author having in several cases of Alopecia areata found bacteria adherent to the roots of extracted hairs, subjected hairs in six selected cases to processes designed to demonstrate the existence of organisms, should they be present, in the substance of the diseased hairs. In five cut of the six cases an object was observed in the hairs which he believes to be a bacterium. It was seen as a rounded or elongated spheroid, and was found frequently in pairs, the long diameter of the two spheroids forming a continuous straight line. Sometimes three were found in line, a delicate rod-shaped sheath enveloping the three. These bodies were, as was shown by the processes to which the hairs were subjected, neither oily particles nor crystals, and they could be distinguished from the granules always present in hairs. In all the cases their size and form were the same, and they had the refractive qualities of bacteria. In hairs which were only slightly affected they were found between the inner root-sheath and the hair-shaft, and in small clusters on the hair-shaft beneath the cuticle of the hair. In hairs which were much diseased they were found in great numbers inside the cuticle of the hair, in the disintegrated hair substance. Some hairs were found split into ribbon-like bands not far from the root and the organisms were found on the bands. They were found only in the part of the hair which is under the surface of the skin, and most abundantly not far from the root. In seven consecutive cases the diseas® was at once and definitely arrested by a treatment designed to destroy the vitality of any bacteria which might be present on the surface of the skin, and at the same 1881.] Dr.G. Thin. Adsorption of Pigment by Bacteria. 503 time to present a mechanical obstacle to their progress in growth from one hair follicle to another.* IV. “On the Absorption of Pigment by Bacteria.” By GEORGE Tun, M.D. Communicated by Professor HUXLEY, Sec. B.S. Received February 19, 1881. Whilst occupied with cultivation of ringworm hairs in vitreous humour at a temperature of 92 to 98° F., I had occasion to observe in studying the hairs under the microscope, amongst the forms of bacteria which were invariably found in these cultivations, certain appearances that seem worthy of note. For the present, I shall limit my remarks to one of these ap- pearances. It is known that certain fungi possess the property of taking up colouring matter from the medium in which they grow; and I have had occasion to observe in the Trichophyton tonsurans that both in man and in the horse the fungus may acquire a dark colour from absorbed pigment. In the case of the horse, I have found the mycelial wall represented by an apparently empty dark tube; and I have found, at the same time, spores blackened with a coating of pigment. I have found an analogous appearance in bacteria. The bacteria found in these cultivations are seen in the transition forms of a spore or coccus, an elongating spore, rods, elongated rods, sometimes of great length, long rods, with the first appearance of a differentiation of the protoplasm into sporules, and finally as tubes full of spores or cocci. These appearances have been now followed in several specific organisms, and notably, and first of all, in the Bacillus anthracis. They would seem to indicate the ordinary life-history of at least many bacteria. I observed that frequently the preparations contained long bacteria rods which had taken up pigment from the hair. This pigment was often found at one end of a long rod, whilst towards the other end the rod was free from it; and in the part of the rod in which the pigment was found the spore formation could, in several instances, be * As treatment which is destructive of bacteria would also arrest the develop- ment of a fungus, it is desirable to add that in none of these cases, nor in previous ones, was the author able to find the fungus described by Gruby, although a large number of hairs were examined. The examinations thus made were so exhaustive that he can only explain the alleged existence of a fungus in this disease by assum- ing that the distinction between Alopecia areata and some of the forms of ringworm has not been always kept in view. ZNee, 504 Mr. W. M. Hicks. On Toroidal Functions. [Mar. 3, seen to be more advanced than at the part which was free from pig- ment. The pigment was packed in the tubes around and between the spores; but, by focussing, it could be seen that the substance of the | spore was free from it. The free spores and short rods were free from pigment. The bacteria in which it was observed showed no other peculiarities, and were of about the same calibre as the rod bacteria usually observed. The fact is noted as affording proof that bacteria can take up minute solid particles through their walls. V. “On Toroidal Functions.” By W. M. Hicks, M.A. St- John’s College, Cambridge. Communicated by J. W. L. GLAISHER, F.R.S. Received February 21, 1881. (Abstract. ) This paper contains the development of a theory for functions which satisfy Laplace’s equation, and are suitable for conditions given over the surface of a circular anchor ring, and which therefore seem important in the possibility of their application to the theory of vortex rings, as well as other physical problems. From the nature of the case, it will not be easy to give an intelligent and full abstract of the results without making it unduly long, but it may be possible to give some idea of its scope and the method of development. Curvilinear co-ordinates are employed, the orthogonal surfaces being those formed by the revolution of a system of circles through two fixed points, and the circles orthogonal to them, whilst the third system are planes through the axis of revolution. Calling these v, U, W, it is shown that any potential function can be expanded in the form— p= V cosh u—cos v EE (APn 2+ BQn.n) cos (nv +2) cos (mw+ Bf) where Pring Qn.n are particular integrals of a certain differential equa- tion, and which are the toroidal functions whose discussion forms the principal part of the paper. They are in fact the same as spherical harmonics of the first and second kinds of imaginary argument, and of orders of the form (2p+1)/2. It is shown how the P can be expressed in terms of the first and second complete elliptic integrals F, H; and the Q in terms of the complementary integrals F’, E’. Several in- teresting results are arrived at, amongst others on relations between the P and Q functions, e.g., between the zonal functions (m—v) Prx1Q.—PQua=5/(nt+D). The P, serve for expansions in the space outside a tore, whilst the Q, serve for space within. 1881.] Microscopical Researches in High Power Definition. 505 Section 11 is devoted to the consideration of zonal functions, 2.e., functions suitable when the conditions are symmetrical about an axis. Section 1 deals with the general case, whilst in the last section illustrations of the use of the functions are given by application to several problems, such as the potentials of tores under the action of an electrified ring, or point of electricity, and the velocity potential when a tore moves parallel to itself in a fluid. Among the results obtained, which may be mentioned here, is the electrical capacity of an anchor ring. When the section of the ring is not very large com- pared with the central opening, a very close approximation is given by the formula— SO Bien EH’ / Roe 2 where SS R+ JR R, 7 being the radii of the circular axis, and generating circle of the ring respectively. The approximation is so close that the formula only makes an error of about ‘3 per cent. when r is so large as 1 R. If a tangent be drawn from the centre to the anchor ring, anda sphere be described with this for radius, the capacity of the tore measured in terms of that of the sphere is when R=10r this is -36049, when R=5r this is ‘43405. VI. “Microscopical Researches in High Power Definition. Pre- liminary Note on the Beaded Villi of Lepidoptera-Scales as seen with a Power of 3,000 Diameters.” By Dr. Royston-Picott, F.R.S. Received January 15, 1881. In carrying out the investigation of the molecular structure of imsect scales, under the finest attainable amplification, the discovery has been made that the striated surfaces of these scales, though appearing approximately beaded, are really covered with villi, chenille or velvet pile, terminating in a spherule. The recognised object of these striz regarded as corrugations is to give strength to a most delicate tissue, which are again supported by ross strice. Upon these transverse striz I have discovered villi erected 506 Mr. W. H. Preece. On the Conversion of [Mar. 10, upon them by twos and threes, and summits consisting of a refracting spherule. This very difficult observation appears to open a new field of research. The object upon which these beaded villi were first. detected is the scale of the Vanessa Atalanta, or Red Admiral. March 10, 1881. THE PRESIDENT in the Chair. The Presents received were laid on the table, and thanks ordered for them. The following Papers were read :— I. “On the Conversion of Radiant Energy into Sonorous Vibra- tions.” By WititiaM Henry PREECE. Communicated by the PRESIDENT. Received February 21, 1881. Messrs. Graham Bell and Sumner Tainter* have shown that, under certain conditions, intense rays of light, if allowed to fall with periodic intermittence upon thin disks of almost every hard substance, will set up disturbances in those disks corresponding to this periodicity which result in sonorous vibrations. Mr. Bell has subsequently shown that such effects are not confined to hard substances, but that they can be produced by matter in a liquid form. These discoveries have elicited a considerable amount of interest, and have led to the inquiry whether the sonorous effects are due, as the discoverers themselves surmised, to light, or as the President of the Royal Society, Professor Tyndall, and others have suggested to radiant heat. ‘ Messrs. Bell and Tainter have partially answered this question by showing that the disturbances are not necessarily due to light, for they found that sheets of hard rubber or ebonite—a substance opaque to lhght—do not entirely cut off the sounds, but allow certain rays to pass through, which continue the effect. M. Mercadier, who has studied the subject with great care,t has shown that the effects are confined to the red and ultra-red rays. Moreover, Professor Tyndall has shown? that gases, such as sulphuric ether, which he had proved to be highly absorbent of heat rays, while they are transparent to * American Association for the Advancement of Science. Boston, August 27, 1880. + “Comptes Rendus,” tome 91, p. 929. tf “ Journal of the Society of Telegraph Engineers,” vol. 9, p. 404. 1881.] Radiant Energy into Sonorous Vibrations. 507 light rays, are remarkably sensitive to this intermittent action. Dr. Tyndall has more recently read a paper before the Society* proving that these sonorous effects are a function of all gases and vapours ‘ absorbing radiant heat, and that the intensity of the sounds produced is a measure of this absorption. The negative proof of Messrs. Bell and Tainter can be rendered positive if it can be shown that ebonite is diathermanous. The author provided himself with several sheets of different substances, and a sensitive radiometer. A standard candle and a lime-light were used as sources of energy, the former fixed four inches and the latter four feet from the radiometer, which was carefully screened from all dis- turbing influences but that of the source. The number of revolu tions made by the radiometer per minute was counted, first without any screen, and then with each sheet successively interposed; and the average of several observations was taken. The following is the result, and the numbers indicate the relative diathermancy of the substances used to the source of light used :— 1. Experiments on Diathermancy. Source of radiant energy. Material. Candle, 4 inches. | Lime-light, 4 feet. SAT ae «sie « sen 100 100 Ebonite, No. 1 ( 4, millim. ye 60 91 i: Pe eaGouniliina,) >: 24.°3 79 °3 » me Hp eee 24.3 79 °3 ” » & ” sees 24 °3 68 °2 ” » O 24°3 68 °2 F » 6 (4 savin. ). 0 9 India-rubber MGabIVe)i one aaa: 4A 3 61 °4 33 (prepared) . yes 60 54:°5 iy (vulcanized) . O 0 (and ozoker exit). 0 6°8 Ozokerit (‘5 millim a 0°14 9 Carbon (2 millims.) . Sieh on 0 @arbomised paper 6. .-.. oe ee. 0 MEE MOOISCAD «5 wake eo ee e's 5.00 0 45 Witremmote paper'...... 2.2... 0) 4°5 MIMO MENON, 1. 5s sc wee en a « 0 "LISSTLG c.g ce et eRe REIS 0°6 Ebonite was, however, proved to be very variable, and while some pieces proved to be as diathermanous as rocksalt, others of the same thickness were found to be quite athermanous. Hbonite therefore, being sometimes diathermanous and opaque, it is clear that the sonorous vibrations of Bell and Tainter are the result of * “ Proc. Roy. Soc.,” vol. 31, p. 307. 508 Mr, W. H. Preece. On the Conversion of.) Mars os disturbances produced by some thermic action rather than by any luminous effect. Several other experiments made by them confirm this conclusion, notably those made upon crystals of sulphate of copper, a substance which Mr. Crookes has shown to be highly opaque to rays of low refrangibility.* Now, the questions arise, is this thermic action expansion and con- traction of the mass due to its absorption of heat? Or is it a disturb- ance due to molecular pressure similar to that which produces the rotation of the radiometer P Or is it due to some other cause ? The argument against the first assumption when applied to hard disks, is that time is a material element in such actions, and that the rate of cooling of warmed diaphragms is too slow to admit of such effects. Lord Rayleigh has questioned the validity of this argument, and has shown that if the radiating power of the body experimented on were sufficiently high a slow rate of cooling would be favourable to rapid fluctuations of temperature. It became desirable to test this point experimentally. The following apparatus was constructed for the purpose. | AB is a thin strip cr wire 6 centims. in length of the substance to be examined, fixed to a platinum “make and break” M, and adjusted to a lever S, round whose axis is fastened a silk thread, the end of which is attached to the strip or wire at A, and whose position could be adjusted by a screw C. Any variation of tension due to expansion or contraction of the wire would produce intermission in the electric currents passing through the telephone T, which if periodically pro- duced would result in sonorous vibrations in the telephone. Heat from various sources and at various distances from bright lime-light to dull heat from hot metallic surfaces, was allowed to fall through rotating vanes intermittently on AB; but notwithstanding every pre- caution, and the many materials used, not more than six interruptions per second could be produced, although the system was beautifully sensitive to the smallest changes of temperature. * “ Phil. Trans.,” vol. 169, § 268. + “ Nature,’ January 20, 1881. 1881. ] Radiant Energy into Sonorous Vibrations. 509 The best effect was obtained when AB was a thin ebonite wire about *5 millim. in diameter, and 6 centims. in length. It was evident from these experiments that the sonorous effects of hard disks could not be explained by the change of volume due to the impact of heat rays, and their absorption by the mass of the disk.* Is the action then due to molecular pressure similar to that which produces the rotation of the radiometer ? It is quite true that the radiometer effect is one visible only in very high exhaustions, but Mr. Crookes (“ Phil. Trans.,” vol. 169, § 220) detected “‘the existence of molecular pressure when radiation falls on a black surface in air of normal density.” Whenever radiant energy falls on an absorbent surface in air, such as a disk of blackened wood, its wave-length is degraded or lowered, and it is converted in thermometric heat. The molecules of air striking this warmed surface acquire heat, and move away from it with increased velocity, and as action and reaction are always alike in moving away, they give the body a “kick.” Since there is no such action on the other side of the disk, there is a difference of pressure between the two sides, which gives it a tendency to move away from the source of energy. The effect is very much smaller in air at ordinary pressures than in air at a very low vacuum, because in the former case, the mean free path of the molecules is very small, and the rebounding molecules help to keep back the more slowly ap- proaching molecules. Nevertheless, molecular pressure is experienced, and if of sufficient magnitude and rapidity, it ought to produce sonorous vibrations. It seemed probable that the element of time does not enter here so prominently as in the previous case, for the radiometer effect is a mere surface action of the disk, and not one affecting its mass. Hence it was hoped that the retarding effects would be eliminated. If the sonorous action, therefore, be due to a radiometer action, a difference of effect would be observed if the side * This conclusion was confirmed by subsequent experiments, notably by Experi- ments 7 and 41. 510 Mr. W. H. Preece. On the Conversion of — [Mar. 10, of a disk exposed to the source of energy, be either blackened by lamp- black or camphor carbon, or if it be polished or whitened. An apparatus was constructed similar in principle to that described. by Messrs. Bell and Tainter. The source of light (L) was an oxy- hydrogen lime-light. The rotating disk (R) was of zinc perforated with holes, which could be noiselessly rotated, so as to obtain 1,000 intermissions per second. Glass lenses (G) were employed to focus the light upon the perforations of the rotating disk, and another (G’), to render the rays parallel on the other side of the disk. A mahogany WIS | 5 ool case or cup (C) to retain the disks to be experimented upon was: constructed as shown in section in fig. 3, and fixed 400 centims. from the source L; a, being the disk 5 centims. im diameter, clamped on by screws; 0, a brass tube, to which the india-rubber hearing tube (h) was fixed; c,a circular air space behind the disk 6 centims. in diameter, and 3 millims. to 5 millims deep. Cavities of various dimensions and forms, spherical, conical, and trumpet-shaped, were tried, but the ones described were those which gave the best effects. Haperiment 2.—An ebonite disk well blackened on one side when exposed to the intermittent rays was found to produce sounds, which Professor Hughes estimated to be about 20 as compared with his sonometer scale.* * Professor Hughes’ Sonometer (“ Proc. Roy. Soc.,” vol., 29, p. 56) proves an excellent apparatus to estimate the relative intensity of low sounds, for by shifting the induction coil from one side to the other, we can pass from an absolute zero, or pure silence, to a limit of sound of considerable intensity. The scale divides this space passed over into 100 equal parts, any number of which give a fairly approxi- mate value of the sounds compared. The ear has to determine the equality of the 1881. | Radiant Energy into Sonorous Vibrations. att 3.* A similar ebonite disk equally well whitened, gave slightly less. intense sounds estimated at 18. 4, A zine disk blackened gave sounds =8. 5. A similar disk polished gave only sounds =2. 6. A mica disk blackened gave scarcely any sounds at all. 7. A clean mica disk gave sounds =d. These effects were produced many times, and on different occasions, and they were so unsatisfactory as to throw doubts on the accuracy of the radiometer explanation. They were not so decided as theory led one to anticipate. The effects produced by the zinc disk, though very weak, favoured the theory ; those given by the mica disk com- pletely refuted it; while those given by the ebonite disks were almost of a neutral character. It was, however, thought that if D be the disk (fig. 4), and C the source of light, then if the excursions of the disks to and fro were due to expansion from the absorption of heat, it would first bulge towards A, since the side towards the source of light would expand first. If, on the other hand, it were due to the radiometer effect, it would first bulge towards B. ~ 8. An extremely delicate electrical contact arrangement was con- structed to determine this by means of a telephone, which recorded the excursions to and fro of the disk; but the result was sometimes in one direction, and sometimes in the other. Moreover, the effect was slow, and we failed to obtain more than five distinct vibrations per second. This result raised the question whether in Bell and Tainter’s ex- | periments the disks vibrated at all. intensity of the twe sounds, i.e., of the sonometer and the source investigated, and the value of the latter is given in terms of the scale of the former. * The consecutive figures indicate the number of tle experiments. a” 512 Mr. W. H. Preece. Ohi the Conversion of — [Mar. 10, 9. A delicate microphone was fixed in various ways on the case, fie. 3. Although the sounds emitted in the hearing tube were as intense as indicated in Experiment 1, scarcely any perceptible effect was detected on the microphone. Had the disk sensibly vibrated, its _ vibrations must have been taken up by the case. A microphone never | fails to take up and magnify the minutest mechanical disturbances. It was thus evident that the disk did not play a prime part in this phenomenon, but it appeared as Professor Hughes suggested, that the result might be due wholly to an expansion and contraction of the ,, air contained in the air space ¢, fig. 3. >= “ An entirely new set of cases and disks were now constructed, but of the same dimensions. 10. With a new clean case and an ebonite disk, the sonorous effects were feeble, viz., 15 on the sonometer scale. 11. If, however, a lens (d) were placed close in front of the ebonite - disk a, (fig. 5), the sonorous effects were magnified considerably, rising at once to about 40. 12. A case was constructed similar to that shown in fig. 5, but with a tube at the side, as well as one at the back, communicating with the air cavity in front of the disk, as well as that behind, and whether one listened at one place or the other, the effect was equally good, indicating that the results were most probably due to the expansions of the contained air. 13. When the one tube was stopped and opened by a cork while the other tube was used for listening, the quality of the sounds varied more than the intensity, but there was distinct evidence of variation. 14. The ebonite disk of this case was now fitted with an extremely delicate microphone, which in this case gave good indications upon the telephone, but whether the vibrations were the results of the 1881.] Radiant Energy into Sonorous Vibrations. 513 vibrations of the disk itself, or of the air in which the microphone was placed, was doubtful. 15. If the lens d, fig. 5, were removed, and the disk left supported without any air cavity, either behind or in front of it, no perceptible sound could be obtained, proving that the effects were really due to the vibrations of the confined air, and not to those of the disk. It was therefore determined to dispense with the disk altogether. ‘16. Case (No. 1) similar to fig. 5 was taken, and the disk removed, but the lens remaining, the sonorous effects were mil. 17. Another case (No. 2), also similar to fig. 5, was taken under similar circumstances, 7.e., without the disk, but the effects were very loud—60 ; in fact, the best results which had yet been obtained. Now, the only difference between the one case or cup and the other, was that the one was blacked in the interior, and the other was not. 18. Hence Case No. 1 was again taken without the disk, and though when clean 1t gave no effect, when its interior was blacked by camphor smoke, it gave sounds as strong as those in Experiment 17, viz., 60. It was thus evident that the sonorous effects were materially assisted _ by coating the sides of the containing vessel with a highly absorbent substance, such as the carbon deposited by burning camphor. It re- mained to be seen how far the lens played a part in this phenomenon. 19. The lens was now removed from the front of the case, and it was replaced by a moveable glass plate (1°5 millims. thick) (e) fig. 6; the. sounds were the same, but they gradually ceased on gradually un- covering the front opening of the case, so as to give the air room to expand. 20. The glass plate e was replaced by a heavy rigid plate of rock- salt 13 millims. thick, and the sounds were equally loud, namely, =60. 514 Mr. W. H. Preece. On the Conversion of _[Mar. 10, 21. The plate e was replaced by white note paper. The sounds were very faint but perceptible. 22. It was replaced by thin cardboard, and the effect was nvl. 23. All these effects were produced equally well, whether the cases were placed at C, fig. 2, 400 centims. from the source of light, or 16 centims. from the rotating disk R, but in the latter case their intensity was of course always increased. Hence it is abundantly evident that these sonorous vibrations are due to the motions of the contained air, and not to those of the disk; that they are actually improved by the removal of the disk, that their production is materially assisted by lining the surface of the containing space with an absorbent substance, that they are dependent on the heat rays that pass through, and that they disappear when the rays are cut off from the air cavity by an athermanous diaphragm. 24. Dr. Tyndall having shown in the paper already referred to, that water vapour responded actively to these intermittent actions, a clean empty one-ounce glass flask was taken and exposed to the inter- mittent beams. No sound was produced. 25. It was then filled with water vapour by pouring a small quantity of water into it, and warming it in a flame, fair sounds of an intensity 25 were the result. 26. The flask was filled with the dense smoke from burning camphor, and the sounds were intensified considerably. 27. The case (fig. 6) was taken and a glass plate 1°5 millims. thick fixed in front of it as before. a. When the glass was dry, sounds were 20. b. When the glass was wetted on the inside, sounds were 25. 28. Another clear one-ounce glass flask was taken. a. When clear, sounds = 0. b. When filled with tobacco smoke, sounds = 5. c. When filled with heavy camphor smoke, sounds = 30. 29. One side of the flask was blackened on the outside, the other side remaining clear. a. On exposing the clear side to the light fair sounds 25 were obtained. b. On exposing the blackened side, no sounds were produced. 30. The flask was blackened 7 the interior on one side only. a. When the blackened side was near the source, sounds = 25. b. When it was away from the source, sounds = 30. c. When the flask was cleaned, all sounds disappeared. 31. A thin glass plate was now blackened on one side and placed i0 front of the case, fig. 6. a. When the black surface was outside, no sownds were ob- tained. 1881. ] Radiant Energy into Sonorous Vibrations. 515 b. When the black surface was inside, good sounds, 30, were the result. c. When the glass was cleaned, the sounds became = 50. 32. An ebonite plate was similarly treated. a. When the blackened surface was outside, sounds = 15 were obtained. 6. When the blackened surface was inside, the sounds were=3. This being an anomalous result, several experiments were now made to test the behaviour of opaque and transparent bodies, when used as disks, for while in the previous experiments the effect was greatest when the blackened surface faced the interior, here we find the opposite result produced, viz., the greatest effect was produced when the blackened surface was on the exterior. 33. Another ebonite disk 0°6 millim. thick was made dull on both sides by rubbing it with emery paper. It was fixed in case (No. 2), fig. 5, without the lens. a. It gave sounds = 15. b. It was now blacked on one side, and when that side was turned to the source, it gave sounds = 30. c. The unblackened side was turned to the source, and it gave sounds = 15. 34. A thin glass plate (1°5 millims. thick)— a. When clear, gave sounds = 50. b. When blackened thinly on one side, and that side turned to the source, it gave sounds = 20. c. When blackened thickly on one side and thinly on the other— 1. Thick side to light, sounds = 0. ) 2. Thin side to light, sounds = 20. 35. A glass plate (3 millims. thick) was blackened on one side. a. Black outside, sounds= 2. pe = inside, a SoU: 36. A clean mica plate (1'2 millims. thick)— a. Gave sounds = 30. b. When blacked on one side. 1. Black outside, sounds = 10. 25°94, inside, Po) 37. Thin copper foil blacked on either side, sounds were nil, 38. A copper disk (0-2 millim. thick) blacked on one side. a. Black outside, sounds = 3. ob \., . inside, Sus 39. Zinc foil blacked on one side. a. Black outside, sounds = 10. ee, . imside, yee 516 Mr. W. H. Preece. On the Conversion of [ Mar. 10, 40. Zine disk (0°7 millim. thick) blacked on one side. a. Black outside, sounds = 10. b. » Inside, ee lt thus appears that transparent bodies behave in an opposite way to opaque bodies. Glass and mica can be rendered athermanous and silent by making the carbon deposit sufficiently thick. Zine, copper, and ebonite can produce sonorous effects by a proper disposition of carbon. The effect in these latter cases may be due either to molecular pressure, in fact, to a radiometer effect, though very feeble in intensity ; or it may be the result of conduction through the mass of the dia- phragm, that is, radiant heat is reduced to thermometric heat by absorption by the carbon deposit on the outside of the disk, this heat is transmitted through the disk and radiated to the absorbent gases in the interior. 41. To test these questions, a delicate microphone was fixed on a zine disk (0°7 millim. thick) without any air-cavity in front of or behind it. a. The disk was blackened ; no measurable trace of sound was perceptible. b. The disk was cleaned, with precisely the same result. 42, The zine disk was now replaced on the case, fig. 5, with the air- - cavity, and sounds = 10. were emitted as before. a. The zinc was neatly covered with white paper—a highly athermanous substance; the sounds were nil. b. The paper was blackened ; the sounds were still nl. c. The zinc was covered with clear mica; faint but unmeasur- able sounds were heard. t d. The mica was blackened; no perceptible sounds were obtained. e. The zine disk was blackened slightly in the usual way; sounds = 10 were obtained. | f. The zine was thickly blackened; all sounds disappeared. 43. Ebonite disks of different thicknesses were used, and layers of carbon of different thicknesses were deposited on the thinnest of them. The sounds became fainter and fainter as the thickness of the layer of carbon and the thickness of the ebonite increased, until they dis- appeared altogether. These experiments fully establish the inference that the effect is one — of conduction, and that the blackened surface of an opaque body like zine acts as though the source of heat were transferred to the outside surface of the disk. 44. Tubes of various sizes and dimensions were now tried, to con- firm Messrs. Bell and Tainter’s observations on tubes. They invariably gave out satisfactory sounds when the intermittent rays were directed 1881. ] Radiant Energy into Sonorous Vibrations. 517 into the interior of the tubes, which were always considerably in- tensified by blackening their interiors, and closing the open end with a glass plate. 45. Since the sounds varied considerably in intensity, according to the number of intermittences per second transmitted, white and ruby glass plates were used, and it was found that the maximum effect (60) was produced when the note corresponding to the intermittences was— With white glass ...... d’=297 vibr. per sec. WHEE ruby yy, 6 aes 2 ee ee a This showed that the element of time was a function of the amount of radiant energy transmitted through the plate. 46. The two cases, which possessed air-cavities of different dimen- sions, were tried with white glass : Case 1 gave b=247 vibr. per sec. Case, 0 =297 = ie Hence it is evident that there is a time element, and that the loud- ness of the note emitted depends upon the rapidity with which the contained air not only absorbs the degraded energy, but upon the rapidity with which it gives up its heat to the sides of the case and the exits open to it. Though the pitch of the maximum note varied with the cavity and the amount of radiant heat transmitted, its quality never varied, notwithstanding the great diversity of materials used as diaphragms. 47. Since these sonorous effects are due to the expansions of absorbent gases under the influence of heat, and since wires are heated by the transference of electric currents through them, it seemed pos- sible that if we inclosed a spiral of fine platinum wire P (fig. 7) na dark cavity, abcd, well blacked on the inside, and sent through it, by means of the wheel-break W, rapid intermittent currents of elec- tricity from the battery B, heat would be radiated, the air would expand, and sounds would result. This was done, and the sounds produced were excellent. In fact, with four bichromate cells, sounds more intense than any previously cbserved were obtained. Furthermore it was evident that if the wheel-break (W) were re: placed by a good microphone transmitter, articulate speech should be heard in the case abed. This was done, and an excellent telephone receiver was the consequence, by means of which speech was per- fectly reproduced. The explanation of these remarkable phenomena is now abundantly clear. It is purely an effect of radiant heat, and it is essentially one due to the changes of volume in vapours and gases produced by the degrada- tion and absorption of this heat in a confined space. The disks in Bell Seb. XXXI. 2 0 518 Mr. W. H. Preece. On the Conversion of _[Mar. 10, and Tainter’s experiments must be diathermanous, and the better their character in this respect the greater the effect; remove them, and the effect is greater still. Messrs. Bell and Tainter* showed that the sounds maintained their fvmbre and pitch notwithstanding variation in the substance of the disk, and M. Mercadier found that a split or cracked plate acted as well as when it was whole. These facts are consistent with the expansion of the contained air, but not with any mechanical disturbance of the disks. Moreover, M. Mercadier showed that the effect was improved by lampblack, but he applied it in the wrong place. The disks may, and perhaps do under certain conditions, vibrate,. but this vibration is feeble and quite a secondary action. The sides of the containing vessel must possess the power to reduce the incident rays to thermometric heat, and impart it to the vapour they confine, and the more their power in this respect, as when blackened by carbon, the greater the effect. The back of the disk may alone act in this respect. Cigars, chips of wood, smoke, or any absorbent sur- faces placed inside a closed transparent vessel will, by first absorb- ing and then radiating heat rays to the confined gas, emit sonorous vibrations. The heat is dissipated in the energy of sonorous vibrations. In all cases, time enters as an element, and the maximum effect depends on * “ Journal of Society of Telegraph Engineers,’ December 8, 1880. 1881.] Radiant Energy into Sonorous Vibrations. 519 the diathermancy of the exposed side of the cavity, on its dimensions and surfaces, and on the absorbent character of the contained gas. The remarkable property which deposited carbon possesses of reducing radiant energy to thermometric heat is strikingly shown by these experiments, and it suggests an important field for inquiry for those who are working in the region of radiant heat. It is only necessary to add that, in carrying out these experiments, I have had the benefit of the presence and advice of Professor Hughes, and the inestimable advantage of the great mechanical skill, philoso- phical character, and experimental ability of Mr. Stroh, without whom, in fact, the inquiry could not have been accomplished. Additional Note. Received March 14, 1881. Professor Stokes has suggested that the action is due not to the ex- pansion of the contained vapour through its absorption of thermome- tric heat generated on the lamp-black surface, but to the contact of the air molecules with this surface. It is clear that when the carbon is warmed, the rapidly moving air molecules which strike it and bound off have their retreating motion increased in velocity. This increased velocity means increased pressure, which in its turn produces increased volume, and this when intermittent, produces sonorous vibrations. This explanation is quite in accordance with the observed facts, for the difference of the intensity of the sounds emitted by dry air and air charged with absorbent vapours is very much less, when a lamp-black surface is used, than was anticipated. Dry air gives excellent results with lamp-black, but is silent without it. Indeed it leads one to conceive that as charging the air with heavy smoke produces the same effect as coating the containing surface with lamp-black, each particle of smoke becomes a warmed surface from which the colliding air molecules, whose dimensions are infinitely smaller, retreat with increased velocity. Moreover, if we conceive the. smoke particles replaced by the compound molecules of absorbent vapours such as sul- phuric ether, olefiant gas, or ammonia, and if we assume the dimen- sions of these molecules greater than those of the air, we have an explanation not only of the absorbent power of these gases, but of the reasons for their behaviour in converting radiant energy into sonorous vibrations. It is clear that if the compound molecule act as a smoke particle, the radiant energy becomes degraded into thermometric heat, for the motion of the ether is transferred to the motion of the mole- cule. The minute air molecules move unaffected in the undulating ether, but the larger compound molecules of the absorbent gas take up the waves of the ether, and assume that form of motion which is known as thermometric heat. Hence, the greater the number of molecules and the larger their dimensions, the greater the absorption 2 0 2 520 Mr. J. B. Hannay. [| Mar. 10, of heat and the more the production of sonorous vibrations, for a greater number of air atoms will collide with warmed surfaces in a given time. That this assumption is justified is proved by the fact that this absorption of radiant energy renders the particles of disso- ciated nitrite of amyl and other vapours visible as well as warm, and therefore they can assume dimensions that are comparable with the particles of smoke. II. “On the Limit of the Liquid State.” By J. B. Hannay, F.R.S.E. Communicated by Professor G. G. STOKES, Sec. R.S. Received February 22, 1881. (Abstract. ) In this paper the author gives an extended account of the work under- taken to determine whether the liquid state extends above the critical temperature, or whether it is bounded by an isothermal line passing through the critical point, as had been indicated in a former paper. A large apparatus was constructed, with several improvements before described, details of construction being given in the full paper. It was found that manometers with small bores gave higher readings than those with larger internal diameter, so the manometers used were of the largest size compatible with the strength required to resist the pressure. The thermometers were carefully prepared by heating and cooling, and compared with the standard at Kew. All the usual pre- cautions were taken to obtain accurate numbers. The critical tem- perature and pressure of the liquids were first determined accurately, and then a quantity of a gas insoluble in the liquid was compressed over the liquid, and the critical temperature again determined under increased pressure. When the densities of the two bodies, e.q., alcohol and hydrogen, are far apart from each other, the gas shows no effect in lowering the critical temperature, as is the case with carbon dioxide and air, whose densities approach much nearer, but simply acts as a spring against which the upper surface of the alcohol bears, thus having a surface free for observation at pressures far above that of the vapour of the liquid. When the liquid passes the critical temperature at any pressure the meniscus is lost, and the fluid freely diffuses into the superincumbent gas, but this does not occur at temperatures below the critical, except where very high pressure has made the gas appreciably soluble in the liquid. Thus the curve of vapour tension, that is, the curve representing the temperatures at which a given pressure will produce liquefaction suddenly becomes isothermal at the critical pomt, and passes along the co-ordinate denoting the critical temperature. As surface tension is the only property by which the liquid state 1881.] On the Limit of the Liquid State. 521 can be known, the capillary height of the liquid at various tempera- tures was next determined. The capillary height becomes zero at the critical temperature, and this is the case whether the pressure is the critical pressure or a higher one. Curves indicating the loss of capillarity with rise of temperature are given, and the observations repeated at higher pressures, the pressures being obtained by com- pressing hydrogen over the liquid. The surface tension is lowered a little by the action of the compressed hydrogen, but the change of Fia. 1. PCE Be Ce aa BREE 113 Psa Ps erate epi ys] ei Ty feshicslie hs (cz feisspy Spee es esp Seale ay, s [ess asta is Paeieis prepa eee peaehe | | : [ees 200 250 S500 : eapillarity follows that of the liquid alone very closely, and the capillarity smks to zero a few degrees below the critical temperature. Nitrogen may be substituted for hydrogen with the same results, and various other liquids being used—carbon bisulphide, carbon tetrachloride, and methyl alcohol. Curves are given, showing their behaviour under high pressures, as in the case of alcohol. In no case could any of the properties of the liquid state be found to exist above the critical temperature. The paper concludes: ‘ Three H22 On the Limit of the Liquid State. [| Mar. 10, curves have been drawn to show the slight depression of the critical temperature with increase of pressure, and these lines have been con- tinued down the curve of vapour pressure to show the break at the critical point.” This will be clearly seen in the annexed fig. 1. The consideration of these results yields a novel mode of looking at the states of matter which I have shown at fig. 2. From this, it appears we might classify matter under four states: First, the gaseous, which exists from the highest temperatures down to an isothermal passing through the critical point, and depending entirely upon temperature or molecular velocity. Second, the vaporous, bounded upon the upper side by the gaseous state, and on the lower by absolute zero, and depending entirely upon the length of the mean free path, because shortening of the mean free path alters the state. Third, the liquid state, bounded upon the upper side by the gaseous, and on the lower by the solid or absolute zero. Fourth, the solid state. Fig. 2. LIQUID- SOLID PRESSURESS— = —. t Lu ia = = @ te Lu o SS LJ fs The gaseous state is the only one which is not affected by pressure alone, or in which the molecular velocity is so high that the collisions cause a rebound of sufficient energy to prevent grouping at any pres- sure. Another distinction between the gaseous and vaporous states is, that the former is capable of acting as a solvent of solids, while the latter has not that power. The two conclusions arrived at are :— . “1st. The liquid state has a limit which is an isothermal passing through the critical point. “2nd. The vaporous state can be clearly defined as a distinct state of matter.” 1881.] Prof. R. W. Atkinson. On the Diastase of Koji. 023 III. “On the) Diastase of Koji.” By R. W. AtTKInson, B.Sc. (Lond.), Professor of Analytical and Applied Chemistry in the University of T6ki6, Japan. Communicated by Pro- fessor A. W. WILLIAMSON, For. Sec. R.S. Received March 3, 1881. (Abstract. ) The paper contains the results of an investigation into the nature of the material used in Japan for converting starch into sugar in the brewing operations. This substance ‘ kdji” is prepared from steamed rice by allowing the spores of a fungus, mixed with the grain, to vegetate over the surface. Details of the manufacture are given, and it is shown that the rice suffers a loss of 11 per cent., calculated upon the substance dried at 100° C. At the same time a great evolu- tion of heat occurs. | A solution of the soluble portion of the “koji” thus prepared is shown to possess properties analogous to those of malt-extract, although differing from it in some important respects. It rapidly inverts cane- sugar and hydrates maltose and dextrin. It liquefies starch-paste, forming at first maltose and dextrin, but giving as ultimate products dextrose and dextrin. Curves accompany the paper showing the action of the extract of ‘‘koji”’ upon starch-paste at different tem- peratures. The paper concludes with an examination of the change which the rice grain undergoes by the growth of the mycelium of the fungus, and it is pointed out that the principal effect produced by the growing plant is to render the insoluble albuminoids previously existing in the rice soluble. 524. Electrical Resistance of Thin Liquid Films. [Mayr. 17, March 17, 1881. THE PRESIDENT in the Chair. The Presents received were laid on the table and thanks ordered for them. ! Professor J. Hmerson Reynolds was admitted into the Society. The following Papers were read :— I. “On the Electrical Resistance of Thin Liquid Films, with a Revision of Newton’s Table of Colours.” By A. W. REINOLD, M.A., Professor of Physics in the Royal Naval College, Greenwich, and A. W. Rucker, M.A., Professor of Physics in the Yorkshire College, Leeds. Communicated by Professor W. GRYLLS ADAMS, F.R.S. Received March 3, 1881. (Abstract. ) The authors have made numerous measurements of the electrical resistance of cylindrical liquid films. Their object was to determine’ whether a thinning film gave evidence by change in its specific re- sistance of an approach to a thickness equal to twice the radius of molecular attraction, and also to devise a method of finding the amount of water which might be absorbed by or evaporated from it. This change of constitution had been neglected by previous observers of the properties of films. The thickness of the films was determined fom their colour. This necessitated a revision of Newton’s table of colours, which was carried out partly by observations on Newton’s rings, partly by more than 2,000 observations on the films themselves. ‘T'wo simultaneous but. independent measures of the thickness of the film were made by observing two portions illuminated by light incident at different angles. In 84 per cent. of the measures made during the final series of experiments described in the paper, the difference between the two values of the thickness thus obtained did not exceed 2 per cent. of its value. The films were enclosed in a glass case in which they could be formed without admitting any external air. Hlaborate precautions were taken to maintain the aqueous vapour within the case at the tension proper to that in contact with the soap solution. The resistance of the films was measured by piercing them with 1881. ] Molecular Electro-Magnetic Induction. 525) gold wires which were in connexion with the opposite pairs of quad- rants of a Thomson’s electrometer. The resistance of the film between the needles was calculated by comparing the deflection caused by the difference of potential of the two wires when a current was passing through the film, with that produced by the difference of potential above and below a known resistance placed in the same circuit. A novel method, the same in principle with the above, was also used to determine the specific resistance of the liquids from which the films were formed. This was deduced from the difference of potential of two platinum wires cemented into a glass tube in which the liquid was. contained. As these were at some distance from the electrodes, errors due to polarisation were got rid of. The results of some test experi- ments made on solutions of sulphuric acid agreed with those of Kohlrausch to within 0-7 per cent. The authors conclude that their experiments show that the specific: resistance of a soap film thicker than 3°74 x 107° centims. (the least thickness at which trustworthy observations were made) is inde- pendent of the thickness, and is equal to that of the liquid from which it is formed. They have, therefore, detected no indication of an approach to a thickness equal to the diameter of molecular attraction, and this leads. to the deduction that its magnitude must either be less than is supposed by Quincke (0°5 x 10-5 centims.), or that the mean specific resistance of the surface layer, the thickness of which is equal to that magnitude, does not differ by 17 per cent. from that of the liquid in mass. They have further found that soap films, even in an enclosed space,, may, if the precautions above referred to are not. taken, readily lose 23 out of the 57°7 volumes of water contained in every 100 volumes of solution, and their experiments show that this quantity may probably be largely exceeded. They think, therefore, that in all accurate observa- tions on soap films these profound modifications of constitution must either be prevented or measured by a method similar to their own. They criticise from this point of view the observations of Plateau* and Liidtge,+ and conclude by pointing out the extreme sensitiveness. of the electrical method of investigation. II. “Molecular Electro-Magnetic Induction.” By Professor D. E. Hugues, F.R.S. Received March 7, 1881. The induction currents balance which I had the honour of bringing before the notice of the Royal Society{ showed how extremely sen- * “Statique des Liquides,’”’ (1873), vol. i, p. 210. + “ Pogg. Ann.,” (1870), vol. cxxxvii, p. 620. t “Proc. Roy. Soc.,” vol. 29, p. 56. 526 Prof. D. E. Hughes. [ Mar. 17, sitive it was to the slightest molecular change in the composition of any metal or alloy, and it gave strong evidence of a peculiarity in iron and steel which its magnetic properties alone failed to account for. We could with all non-magnetic metals easily obtain a perfect balance of force by an equivalent piece of the same metal, but in the case of iron, steel, and nickel it was with extreme difficulty that I could obtain a near approach to a perfect zero. Two pieces of iron cut off the same bar or wire, possessing the same magnetic moment, never gave identical results; the difficulty was, that notwithstanding each bar or wire could be easily made to produce the same inductive reaction, the time during which this reaction took place varied in each bar; and although I could easily change its balancing power as regards inductive force by a change in the mass of the metal, by heat or magnetism, the zero obtained was never equal to that obtained from copper or silver. This led me to suppose the existence of a peculiarity in magnetic metals which could not be accounted for except upon the hypothesis that there was a cause, then unknown, to produce the invariable effect. Finding that it would be impossible to arrive at the true cause without some new method of investigation, which should allow me to -observe the effects from an electrical circuit, whose active portion should be the iron wire itself, I constructed an apparatus or electro-magnetic induction balance, consisting of a single coil reacting upon an iron wire in its axis, and perpendicular to the coil itself; by this means the iron or other wire itself became a primary or secondary, according as the current passed through the coil or wire. Now, with this appa- ratus we could induce secondary currents upon the wire or coil, if the coil was at any angle, except when the wire was absolutely perpen- dicular; in this state we could only obtain a current from some dis- turbing cause, and the current so obtained was no longer secondary but tertiary. The whole apparatus, however, is more complicated than the general idea given above, as it was requisite not only to produce effects ‘but to be able to appreciate the direction of the electrical current ob- tained, and have comparative measures of their value. In order to fully ‘understand the mode of experiments, as well as the results obtained, I will first describe the apparatus employed. The electro-magnetic induction balance consists of—Ist, an instru- ment for producing the new induction current; 2nd, sonometer or balancing coils; 35rd, rheotome and battery ; 4th, telephone. The essential portion of this new balance is that wherein a coil is .so arranged that a wire of iron or copper can pass freely through, forming its axis. The iron or copper wire rests upon two supports 20 centims. apart; at one of these the wire is firmly clamped by two ‘binding screws; the opposite end of the wire turns freely on its sup- 1381. ] Molecular Electro-Magnetic Induction. 527 port, the wire being 22 centims. long, having 2 centims. projection beyond its support, in order to fasten upon it a key or arm which shall serve as a pointer upon a circle giving the degrees of torsion which the wire receives from turning this pointer. A binding screw allows us to fasten the pointer at any degree, and thus preserve the required stress the time required. The exterior diameter of the coil is 55 centims., having an interior vacant circular space of 34 centims., its width is 2 centims.; upon this is wound 200 metres of No. 32 silk-covered copper wire. This coil is fastened to a small board so arranged that it can be turned through any desired angle in relation to the iron wire which passes through its centre, and it can also be moved to any portion of the 20 centims. of wire, in order that different portions of the same wire may be tested for a similar stress. The whole of this instrument, as far as possible, should be con- structed of wood, in order to avoid, as far as possible, all disturbing inductive influences of the coil upon them. The iron wire at its fixed end is joined or makes contact with a ‘copper wire, which returns to the front part of the dial under its board and parallel to its coil, thus forming a loop, the free end of the iron wire is joined to one pole of the battery, the copper wire under the board is joined to the rheotome and thence to the battery. The coil is joined to the telephone; but, as in every instance we can either pass the battery current through the wire, listening to its induc- tive effects upon the wire, or the reverse of this ; I prefer, generally, in order to have no voltaic current passing through the wire, to join the iron wire and its loop direct to the telephone, passing the voltaic eurrent through the coil. In order to balance, measure, and know the direction of the new induction currents by means of a switching key, the sonometer* I described to the Royal Society is brought into the circuit. The two exterior coils of the sonometer are then in the circuit of the battery, and of the coil upon the board containing the iron wire or stress bridge. The interior or movable coil of the sonometer is then in the circuit of the iron wire and telephone. Instead of the sonometer con- structed as described in my paper to the Royal Society, I prefer to use one formed upon a principle I described in “‘ Comptes Rendus,” December 30, 1878. This consists of two coils only, one of which is smaller and turns freely in the centre of the outside coil. The exterior coil being stationary, the centre coil turns upon an axle by means of a long (20 centims.) arm or pointer, the point of which moves over a graduated arc or circle. Whenever the axis of the interior coil is perpendicular to the exterior coil, no induction takes place, and we * “Proc. Roy. Soc.,”’ vol. 29, p. 65. 528 Prof. D. E. Hughes. [Marte have a perfect zero: by turning the interior coil through any degree we have a current proportional to this angle, and in the direction in which it is turned. As this instrument obeys all the well-known laws for galvanometers, the readings and evaluations are easy and rapid. If the coil upon the stress bridge is perpendicular to the iron wire, and if the sonometer coil is at zero, no currents or sounds in the tele- phone will be perceived, but the slightest current in the iron wire produced by torsion will at once be heard; and by moving the sono-. meter coil in a direction corresponding to the current, a new zero will be obtained, which will not only balance the force of the new current but indicate its value. A perfect zero, however, will not be obtained with the powerful currents obtained by the torsion of 2 milims. diameter iron wire, we then require special arrangements of the sono- meter which are too complicated to describe here. The rheotome is a clockwork, having a rapid revolving wheel which gives interruptions of currents in fixed cadences in order to have equal intervals of sound and silence. J employ four bichromate cells or eight Daniell’s elements, and they are joined through this rheotome to the coil on the stress bridge, as I have already described. The magnetic properties of iron, steel, nickel, and cobalt, have been so searchingly investigated by ancient as well as by modern scientific authors, that there seems little left to be known as regards its molar magnetism. JI use the word molar here simply to distinguish or separate the idea of a magnetic bar of iron or steel magnetised longi- tudinally or transversely from the polarised molecules which are supposed to produce its external magnetic effects. Molar magnetism, whilst having the power of inducing an electric current in an adjacent wire, provided that either has motion, or the magnet a change in its magnetic force, as shown by Faraday in 1832, has no power of inducing an electric current upon itself or its own molar constituent, either by motion or change of its magnetic moment. Molecular magnetism (the results of which, I believe, I have been the first to obtain) has no, or a very feeble, power of inducing either magnetism or an electric current in an adjacent wire, but it possesses. the remarkable power of strongly reacting upon its own molar wire, inducing (comparatively with its length) powerful electric currents, in a circuit of which this forms a part. In some cases, as will be shown, we may have both cases existing in the same wire; this occurs when the wire is under the influence of stress, either externa! or internal; it would have been most difficult to- separate these two, as it was in my experiments with the induction balance, without the aid of my new method. Ampere’s theory supposes a molecular magnetism or polarity, and. that molar magnetism would be produced when the molecular mag- #351; | Molecular Electro-Magnetic Induction. 529 netism became symmetrical ; and his theory, I believe, is fully capable of explaining the effects I have obtained, if we admit that we can rotate the paths of the polarised molecules by an elastic torsion. Matteucci made use of an inducing and secondary coil in the year 1847,* by means of which he observed that mechanical strains in- creased or depressed the magnetism of a bar inside this coil. Wertheim published in the ‘‘ Comptes Rendus,” 1852,+ some results similar to Matteucci; but in the ‘“‘ Annales de Chimie et de Physique,” 1857,* he published a long series of most remarkable experiments, in which he clearly proves the influence of torsion upon the increment or decrement of a magnetical wire. Vilari showed§ increase or diminution of magnetism by longitudinal pull according as the magnetising force is less or greater than a certain critical value. Wiedemann,|| in his remarkable work “‘ Galvanismus,”’ says that an iron wire through which an electric current is flowing becomes mag- netised by twisting the wire. This effect I have repeated, but found the effects very weak, no doubt due to the weak battery i use, viz., four quart bichromate cells. Sir W. Thomson shows clearly in his remarkable paper ‘‘ Effects of Stress on the Magnetisation of Iron, Nickel, and Cobalt,” the critical value of the magnetisation of these metals under varying stress, and also explains the longitudinal magnetism produced by Wiedemann as due to the outside molar twist of the wire, making the current pass as in a spiral round a fixed centre. Sir William Thomson also shows clearly the effects of longitudinal as well as transversal strain, both as regards its molar magnetism and its electric conductivity. My own researches convince me that we have in molecular mag- netism a distinct and separate form of magnetism from that when we develop, or render evident, longitudinal or transversal magnetism, which I have before defined as molar. Molecular magnetism is developed by any slight strain or twist other than longitudinal, and it is only developed by an elastic twist ; for, however much we may twist a wire, provided that its fibres are not separated, we shall only have the result due to the reaction of its remaining elasticity. If we place an iron wire, say 20 centims. long, 1 millim. diameter, in the axis of the coil of the electro-magnetic balance, and if this wire is joined, as described, to the telephone, we find that on passing a electric * “ Compt. Rend.,” t. xxiv, p. 301, 1847. + “Compt. Rend.,” t. xxv, p. 702, 1852. t “Ann. de Chim. et de Phys.,” (8), t. 1, p. 385, 1857. § “ Poggendorff’s Annalen,”’ 1868. || Wiedemann. “Galvanismus,” p. 447, { ‘“ Phil. Trans.,’’ 1879, p. 55. 530 Prof. D. E. Hughes. Men! te current through the inducing coil no current is perceptible upon the iron wire; but if we give a very slight twist to this wire at its free end—one-eighteenth of a turn, or 20°—-we at once hear, clear and comparatively loud, the currents passing the coil; and although we only gave a slight elastic twist of 20° of a whole turn, and this spread over 20 centims. in length, making an extremely slight molar spiral, yet the effects are more powerful than if, using a wire free from stress, we turned the whole coil 40°. The current obtained when we turn the coil, as just mentioned, is secondary, and with the coil at any angle any current produced by its action, either on a copper, silver, iron, or steel wire ; in fact, it is simply Faraday’s discovery ; but the current from an elastic twist is no longer secondary under the same ~ conditions, but tertiary, as I shall demonstrate later on. The current passing through the coil cannot induce a current upon a wire perpen- dicular to itself, but the molecules of the outside of the wire, being under a greater elastic stress than the wire itself, they are no longer perpendicular to the centre of the wire, and consequently they react upon this wire as separate magnets would upon an adjacent wire. It might here be readily supposed that a wire having several twists, or a fixed molar twist of a given amount, would produce similar effects. It, however, does not, for in most cases the current obtained from the molar twists are in a contrary direction to that of the elastic torsion. Thus, if I place an iron wire under a right-handed elastic twist of 20°, i find a positive current of 50° sonometer ; but if I continue this twist so that the index makes one or several entire revolutions, thus giving a permanent molar twist of several turns, I find upon leaving the index free from any elastic torsion, that I havea permanent current of 10°, but it is no longer positive, but negative, requiring that we should give an elastic torsion in the previous direction, in order to produce a positive current. Here a permanent elastic torsion of the molecules is set up in the contrary direction to its molar twist, and we have a negative current, overpowering any positive current which should have been due to the twisted wire. The following table shows the influence of a permanent twist, and that the current obtained when the wire was freed from its elastic tor- sion was in opposition to that which should have been produced by the permanent twist. Thus, a well-softened iron wire, 1 millim. in dia- meter, giving 60° positive current for a right-handed elastic torsion of 20°, gave after 1°80 permanent torsion a negative current of 10°. 1 complete permanent torsion (right-handed) negative .... 10 2 9? 99 99 ecee 15 3 99 99 99 eeee 15 4 99 99 99 ecco 16 o rs 2 29 roe 12 1881. | Molecular Electro-Magnetic Induction. 531 6 complete permanent torsion (right-handed) negative .... 10 is Ms Es eat ash MD 8 M 35 a BS eo) 4s 9 e 30 53 3 10 3 5 3 At this point the fibres of a soft wire commence to separate, and we have no longer a complete single wire, but a helix of separate wires upon a central structure. If now, instead of passing the current through the coil, I pass it through the wire, and place the telephone upon the coil circuit, I find that I obtain equaily as strong tertiary currents upon the coil as in the previous case, although in the first case there was produced longitudinal electro-magnetism in the perpendicular wire by the action of the coil, but in the latter case none or the most feeble electro-magnetism was produced, yet in these two distinct cases we have a powerful current produced not only upon its own wire, but upon the coil, thus proving that the effects are equally produced both on the wire and coil. If we desire, however, in these reversible effects to produce in both cases the same electromotive force, we must remember that the tertiary current when reacting. upon its own short wire produces a current of great quantity, the coil one of comparative higher intensity. We can, however, easily convert the great quantity of the wire into one of higher tension by passing it through the primary of a small induction coil whose resistance is not greater than one ohm. We can then join our telephone, which may be then one of a high resistance, to the secondary of this induction coil, and by this means, and without changing the resistance of the telephone, receive the same amount of force, either from the iron wire or the coil. Finding that iron, steel, and all magnetic metals produce a current by a slight twist, if now we replace this wire by one of copper or non- magnetic metals we have no current whatever by an elastic twist, and no effects, except when the wire itself is twisted spirally in helix, and whatever current we may obtain from copper, &c., no matter if from its beg in spiral or from not being perpendicular to the axis of the coils, the currents obtained will be invariably secondary and not tertiary. If we replace the copper by an iron wire, and give it a certain fixed torsion, not passing its limit of elasticity, we find that no increase or decrease takes place by long action or time of being under strain. Thus a wire which gave a sonometric force of 50° at the first observation, remained perfectly constant for several days until it was again brought to zero by taking off the strain it had received. Thus we may consider that as long as the wire preserves its elasticity, exactly in the same ratio will it preserve the molecular character of its magnetism. O32 Prot. Dea eine hess: | Mano alige It is not necessary to use a wire to produce these effects; still more powerful currents are generated in bars, ribbons, or sheets of iron; thus, no matter what external form the iron may possess, it still produces all the effects I have described. It requires a great many permanent twists in a wire to be able to see any effect from these twists, but if we give to a wire, 1 millim. diameter, forty whole turns (or until its fibres become separated) we find some new effects; we find a small current of 10° in the same direction as its molar twist, and on giving a slight twist (20°) the sonometric value of the sound obtained is 80°, instead of 50°, the real value of a similar untwisted wire; but the explanation will be found by twisting the wire in a contrary direction to its molar twist. We can now approach the zero but never produce a current in the contrary direction, owing to the fact that by the spiral direction, due to the fibrous molar turns, the neutral position of its molecules is no longer parallel with its wire, but parallel with its molar twist, con- sequently an elastic strain in the latter case can only bring the mole- cules parallel with its wire, producing no current, and in the first case the angle at which the reaction takes place is greater than before, consequently the increased value of its current. The measurements of electric force mentioned in this paper are all sonometric on an arbitrary scale. Their absolute value has not yet been obtained, as we do not, at our present stage, require any except comparative measures.* Thus, if each wire is of 1 millim. diameter and 20 centims. long, all render the same stress in the axis of its coil. I find that the following are the sonometric degrees of value :— Ob OnaN Hy Aas Boe een te 60 Tertiary current. ard cirim trom. saree eee 50 s ye Borbisteelict sees. Rese aee ar Ad uf on Hard tempered steel ............ 10 Fe = Coppers silveriex. 22 eae —0 Copper helix, 1 centim. diameter, 20 turns in 20 centims......... 45 Secondary currents. Tron; spiral (dittovc; 5 ee, Ad i. 35 Sibeel ears he ae tals A5 99 99 The tertiary current increases with the diameter of the wire, in a proportion which has not yet been determined ; thus, an ordinary hard iron wire of 1 millim. diameter giving 50°, one of 2 millims. diameter gave 100°; and the maximum of force obtained by any degree of torsion is at or near the limit of elasticity, simce as soon as we pass this point, producing a permanent twist, the current decreases, as I have already shown in the case of a permanent twist. Thus, the * 50° sonometer has the same electromotive force as 0°10 of a Daniell battery. 1881.| Molecular Electro-Magnetie Induction. 533 critical point of 1 millim. hard iron wire was 20° of torsion, but in hard steel it was 45°. Longitudinal strains do not produce any current whatever, but a very slight twist to a wire, under a longitudinal strain, produces its maximum effects: thus, 20° of torsion being the critical point of iron wire, the same wire, under longitudinal strain, required but from 10° to 15°. It is very difficult, however, to produce a perfect longitudinal strain alone. I have, therefore, only been able to try the effect of longitudinal strain on fine wires, not larger than | millim. in diameter, but as in all cases, no effect whatever was produced by longitudinal strain alone, I believe none will be found if the wire be absolutely free from torsion. The molecules in a longitudinal strain are equally under an elastic strain as in torsion, but the path of their motion is now parallel with its wire, or the zero of electric inductive effect, but the longitudinal and transverse strains of which the compound strain is composed, react upon each other, producing the increased effect due to the compound strain. The sonometer is not only useful for showing the direction of the current and measuring it by the zero method, but it also shows at once if the current measured is secondary or tertiary. If the current is secondary its period of action coincides with that of the sonometer, and a perfect balance, or zero of sound, is at once obtained, and its value in sonometric degrees given, but if the current is tertiary, no zero is possible, and if the value of the tertiary is 60°, we find 60° the nearest approach to zero possible. But by the aid of separate induction coils to convert the secondary into a tertiary, a perfect zero can be obtained if the time of action and its force correspond to that which we wish to measure. If I place a copper wire in the balance and turn fhe coils at an angle of 45°, I obtaim a current for which the sonometer gives a perfect zero at 50°, voveonetnines as already said, that it is eecondaee, If I now -replace the copper by an iron wire, the coil remaining at 45°, I have again exactly the same value for the iron as copper, viz., 50°, and in both cases secondary. Now, it is evident that in the case of the iron wire there was produced at each passage of the current a strong electro-magnet, but this longitudinal magnetism did not either change the character of the current or its value in force. _ A most beautiful demonstration of the fact that longitudinal mag- netism produces no current, but that molecular magnetism can act equally as well, no matter the direction of the longitudinal magnetism, consists in forming an iron wire in a loop, or taking two parallel but Separate wires, joined electrically at their fixed ends, the free ends being each connected with the circuit, so that the current generated must pass up one wire and down the adjacent one. On testing this loop, and if there are no internal strains, complete silence or absence VOL. XXXI. 2 P 534 Prof D. E. Hughes. [ Mar. 17, of current will be found. Now, giving a slight torsion to one of these wires in a given direction, we find, say, 50° positive; twisting the parallel wire in a similar direction produces a perfect zero, thus, the current of the second must have balanced the positive of the first. If, instead of twisting it in similar directions, we twist it in the con- trary direction, the sounds are increased in value from 50° positive to 100° positive, showing, in this latter case, not only a twofold increase of force, but that the currents in the iron wires travelled up one wire and down the other, notwithstanding that both were strongly magnetic by the influence of the coil in one direction, and this experiment also proves that its molar magnetism had no effect, as the currents are equally strong in both directions, and both wires can double or efface the currents produced in each. If, instead of two wires we take four, we can produce a zero, or a current of 200°, and with twenty wires we have a force of 1,000°, or an electromotive force of two volts. We have here a means of multiplying the effects by giving an elastic torsion to each separate wire, and joining them electrically in tension. If loops are formed of one iron and one copper wire, we can obtain both currents from the iron wire, positive and negative, but none from the copper, its réle is ‘simply that of a pedlngian upon which torsion has no effect. I have already mentioned that internal strains will give out tertiary currents, without any external elastic strain being put on. In the case of iron wire, these disappear by a few twists in both directions, but in flat bars or forged iron, they aré more permanent; evidently, portions of these bars have an elastic strain, whilst other portions are free, for I find a difference at every inch tested: the instrument, how- ever, is so admirably sensitive, and able to point out not only the strain, but its direction, that I have no doubt its application to large forged pieces, such as shafts or cannon, would bring out most interest- ing results, besides its practical utility ; great care is therefore neces- sary in these experiments that we have a wire free from internal strains, or that we know their value. Maenetising the iron wire by a large steel permanent magnet has no effect whatever. A hard steel wire thus placed becomes strongly magnetic, but no current is generated, nor has it any influence upon the results obtained from molecular movement, as in elastic torsion. A fiat wide iron or steel bar shows. this better than iron wire, as we can here produce transversal, instead of longitudinal, but neither shews any trace of the currents produced by molecular magnetism. I have made many experiments with wires and bars thus magnetised, but as the effect in every case was negative when freed from experimental errors, | will not mention them; but there is one very interesting proof which the instrument gives, that longitudinal magnetism first passes through its molecular condition before and during the discharge, 1881.] Molecular Electro-Magnetic Induction. D390 or recomposition of its magnetism. For this purpose, using no battery, I join the rheotome and telephone to the coil, the wire having no exterior circuit. If Istrongly magnetise the two ends of the wire, I find by rapidly moving the coil, that there is a Faradaic induction of 50° at both poles, but very little or none at the centre of the wire; now fixing the coil at the centre or neutral point of the wire, and listening intently, no sounds are heard, but the instant I give a slight elastic tor- sion to the free pole, a rush of electric tertiary induction is heard, whose value is 40°. Again, testing this wire by moving the coil, I find only @ remaining magnetism of 10, and upon repeating the experiment of elastic torsion, | find a tertiary of 5; thus we can go on gradually dis- charging the wire, but it will be found that its discharge is a recom- position, and that it first passed through the stage I have mentioned. Heat has a very great effect upon molecular magnetic effects. On iron it increases the current, but in steel the current is diminished. For experimenting on iron wire, which gave a tertiary current of 50° positive (with a torsion of 20°), upon the application of the flame of a spirit-lamp, the force rapidly increases (care being taken not to ap- proach red heat), until the force is doubled, or 100 positive. The same effects were obtained in either direction, and were not due to a molar twist or thermo-current, as if care had been taken to put on not more than 10° of torsion, the wire came back to zero at once on removal of the torsion. Hard tempered steel, whose value was 10° whilst cold, with a torsion of 45°, became only 1° when heated, but returned (if not too much heated) to 8° when cold. I very much doubted this experiment at first, but on repeating the experiment with steel several times, | found that on heating it, I had softened the extreme hard (yellow) temper to that of the well-known blue temper. Now, at blue temper, hot, the value of steel was but 1° to 2°, whilst soft iron of a similar size gave 50° of force cold, and 100° at red heat. Now, as I have already shown that the effects I have described depend on molecular elasticity, it proves at least, as far as iron and steel are concerned, that a comparatively perfect elastic body, such as tempered steel, has but slight molecular elasticity, and that heat reduces it, but that soft iron, having but. little molar elasticity, has a molecular elasticity of a very high degree, which is increased by heat. The objects of the present paper being to bring the experimental facts before the notice of the Royal Society, and not to give a theoretical solution of the phenomena, I will simply add, that if we assume with Poisson, that the paths of the molecules of iron are circles, and that they become ellipses by compression or strain, and also that they are capable of being polarised, it would sufficiently explain the new effects. Joule has shown that an iron bar is longer and narrower during magnetisation than before, and in the case of the transverse strain, the exterior portions of the wire are under a far greater strain than those ID 536 Mr. C. G. Willams. | [Mar. 17, near the centre, and as the polarised ellipses are at an angle with the molecules of the central portions of the wire, its polarisation reacts upon them, producing the comparatively strong electric currents I have described. | III. (“On the Action of Sodium upon Chinoline.” By C. GREVILLE WILLIAMS, F.R.S. Received March 8, 1881. In 1867 I made some experiments on the action of sodium upon chinoline and lepidine, and found that a substance was produced which dyed silk a beautiful but fugitive orange coiour. I announced this fact in a paper “ On the Higher Homologues of Chinoline.’* I made analyses of the products at the time, but the difficulties in the way of preparing them pure were so great, and the time at my disposal was so limited, that I did not make public any quantitative results until March, 1878, when I published a short note “‘On the Action of Sodium on Chinoline and Lepidine.”+ In that paper I gave the results of an analysis of a product from chinoline, which agreed with the formula CHUN? HCl, which is obviously that of the hydrochlorate of dichino- line. I also gave an analysis of the nitrate of dilepidine, which agrees almost perfectly with the theoretical values; but I did not enter into the details of the modes of preparation. In the course of my investigation of #-lutidine, it was natural that I should study the action of sodium upon it, but I met with so many and unexpected difficulties that I determined to prepare myself for a new attack upon the subject by a fresh investigation of the action of sodium upon chinoline. As I find that other observers are working upon chinoline, B-lutidine, and f-collidine,¢ I have thought it desirable to bring before the Society the results obtained, although the investigation is still proceeding. Action of Sodium upon Chinoline. The action of sodium on chinoline is exceedingly remarkable, not merely because it polymerises the base, for a similar result, as is well known, takes place with picoline, but because the products have pro- perties which are, I think, different from any yet observed among organic substances. For a yellow oil like dichinoline to yield a true although fugitive dye, in the form of a brilliantly red crystalline * “ Laboratory,’ May, 1867, p. 109. + “ Chemical News,’ March 1, 1878. + Richard, “ Bull. Soc. Chim.,”’ [2] xxxii, 486—489 ; Boutlerow and Wischnegrad- sky, loc. cit., No. 9, June 5, 1880; Oechsner de Coninck, “ Bull. Soc. Chim.,” Nos. 4 and 5, p. 210, September 5, 1880. The latter chemist has repeated several of my older experiments, evidently under the impression that they had not been made before. 1881.] On the Action of Sodium upon Chinoline. D37 hydrochlorate, is probably a unique reaction. To obtain this product of the utmost beauty, it appears to be necessary that the chinoline should be perfectly free from any impurity, except, perhaps, its next homologue. The most successful preparations were made from chino- line obtained from fine crystals of the chromate.* Chinoline prepared from the chromate is almost colourless, and becomes yellow, on keeping, with extreme slowness as compared with the base prepared without that precaution. In the following experi- ments it is to be understood that all the chinoline was obtained from the crystallised chromate. Chinoline was boiled with sodium, the fluid, which became purplish crimson, was treated with water, which at once converted the crimson colour into a dirty yellow. Hydrochloric acid was then added, and the solution became of an intense orange colour. The solution was boiled, filtered, and allowed to stand two days, the crystals of hydro- chlorate of dichinoline were filtered off, and the mother-liquid was precipitated fractionally by solution of platinic chloride. The first precipitate was of a light orange colour, the second a deep orange, the third Naples yellow, the fourth was in the form of a brown crystal- line powder. The platimum was determined in each with the follow- ing results :— No. of precipitate. Percentage of platinum. Deepens vey ayenin elie Susy shaiesiakes «hea > 2 22°59 Ds airs aiciatly cheicnge sayewpardt ses 23°83 STUDI eS ep cody thaecvses mms cosas # yaa 28°30 Vie thes ecpeway i sceporstirg aud cd pa,034,0 28°59 The first result agrees with the numbers required for the formula— 2(C18H'4N?) HCl. PtCl4, which requires 22°18 per cent. of platinum. The second is probably a mixture of the substance having the formula of the first precipitate with some of that having the formula of the third, which latter agrees fairly with a salt having the formula— Cl8H14N?.3HC1.PtCls, which requires 28°00 per cent. of platinum. The formula— C18H'MN? 2HCI1.PtCls, requires 29°51 per cent. There are other formule which agree with * It is much to be desired that those chemists who believe in the identity of chinoline and leucoline, and who possess the latter in a pure state, would study the action of sodium upon it; as, if it yields the crystalline scarlet hydrochlorate, the question might be considered as settled. 538 Mr. C. G.- Williams. [Mar. 17, the numbers obtained, but they do. not appear to me so readily admis- sible. For instance, a substance having the formula— 2(C18H14N2) PtCl, would require 23°13 per cent. of platinum, which would agree with the amount of metal obtained from the second precipitate, but the formation of such a substance in the presence of free hydrochloric acid appears most unlikely. Nevertheless, it is remarkable that the platinum salts obtained from the products of the action of sodium on chinoline and #-lutidine, often agree in their percentages of platinum with substances having formule of the polymerised bases united directly to platinic chloride. Action of Sodium Amalgam on Chinoline. 25 grms. of chinoline and 20 grms. of sodium amalgam containing” 10 per cent. of sodiam were mixed. The action commenced in the cold, and red streaks appeared where the base and the amalgam were in contact. When the action ceased in the cold, the mixture was warmed on the water-bath; the reaction started again immediately, and the whole became of a deep red colour. No gas was given off. The next day the mixture had assumed the consistence of thick treacle ; when heated on the water-bath it softened, but the amalgam remained hard ; the fluid had turned from purplish red to yellow, but reddish streaks were still formed on stirring, showing that the reaction was. not complete. . At this stage 5 grms. more amalgam were added. After four or five hours of constant stirring on the water-bath the red streaks ceased to appear, and the whole became a greenish yellow oil, the greater portion of which was poured off, and the residue contaming much undecomposed amalgam was treated with hot water. The amalgam decomposed with violence, and when the action was over excess of hydrochloric acid was added, and the solution was boiled and filtered. Three liquors were taken off and kept separate from each other, each solution gave on cooling crystals of the hydrochlorate of dichinoline;. they were in the form of needles of so brilliant a scarlet that, on com- parison with a sample of the finest vermillion, the latter looked brown by contrast with them. The first solufion yielded 1‘1 grams of air- dried product, the second 0-4, and the third 0°25, in all 1:75 grms. from 25 grms. of chinoline. The scarlet crystals bleach on exposure to ight and become pale brown on drying in the water-oven, and the brown colour itself rapidly bleaches on exposure to light. The mother-liquors of the scarlet crystals on evaporation to a quarter of their original bulk, deposited a pale yellow precipitate too small for analysis ; it was nearly insoluble in cold water. The mother-liquors affording no further crystals on evaporation, were treated with excess of potash to enable the chinoline to be 1881.] = On the Action of Sodium upon Chinoline. 539 recovered ; 11 grms. were obtained, being 44 per cent. on the chinoline taken ; deducting the recovered chinoline from that originally em- ployed, the produce of the scarlet crystals become 12°5 per cent. on the base originally taken. Action of Sodium Amalgam on the Recovered Chinoline. The recovered chinoline was dried by sticks of potash for a short time, and then rectified to see if its boiling-point had undergone any alteration by the treatment with sodium amalgam ; however, it came over at almost exactly the same point as it did before. It is very remarkable that in spite of the fact last mentioned, the product of the action of the amalgam upon the recovered base was of a totally different character to that of the same reagent upon the original chinoline. The 11 grms. of recovered chinoline were treated with 20 grms. of amalgam, effervescence took place, and much heat was developed; this was possibly caused by traces of moisture remaining in the base. When the effervescence was over, 5 grms. more amalgam were added, being in all 30 grms. for 11 of base, whereas in the first experiment equal parts of base and amalgam were used; this fact has to be remembered in considering the causes of the different result. The red coloration took place as before ; it is, however, a very ephemeral reaction, the colour on a glass rod soon disappears, and does so imme- diately on spreading the substance in a thin layer on the side of the beaker in which the operation is conducted. ' The experiment was made precisely as with the original chinoline, and the reaction appeared to proceed exactly in the same manner as before; but, on boiling out with dilute hydrochloric acid, the product of hydrochlorate of dichino- line was much smaller, and the crystals were too small to be distin- guished as such by the naked eye. The mother-liquors were treated with potash, as before, to enable the chinoline to be recovered, when to my surprise a solid yellow base was obtained, which on boiling some time with water to expel any adhering chinoline, became, on cooling, a hard resinous mass: cn drying in the air.it weighed 7 grms., or 63 per cent. on the 11 grms. of recovered chinoline used. ; In order to gain some insight into the nature of the new solid base, it was converted into a hydrochlorate and fractionally precipi- tated with platinic chloride. 1 grm. was dissolved in 50 cub. centims. of hot diluted hydrochloric acid, on cooling a part separated out; this could have been prevented by a great excess of hydrochloric acid, but, on this occasion, the separation was permitted as a mode of purification. The precipitate was filtered off, and some hydrochloric acid was added to prevent the water in the solution of platinic chloride from causing a further precipitation. On adding the pla- 540 Mr. C. G. Wilhatns. [ Mar. 17, tinum solution, a dense bright yellow precipitate was formed; to the filtrate more platinum solution was added, and so on until four pre- cipitates were obtained. The second, third, and fourth were buff coloured, but the last on standing became of a dirty brown colour. The two last were in too small quantity for analysis. The first precipitate gave 18°47 per cent. of platinum. Assuming for the present that the yellow solid base from the recovered chinoline is isomeric with that which yields the scarlet hydrochlorate, it may be mentioned that a salt having the formula— 2 (CHAN?) 4HCl. PtCl* would require 19°76 per cent. of platmum. The second precipitate gave 23°49 per cent. of platinum, and yielded, therefore, almost the same percentage of the metal as the second precipitate obtained from the product of the action of sodium upon the original chinoline, and the remarks made upon that precipitate apply equally to the present one. Experiments were subsequently made to ascertain if, in presence of excess of hydrochloric acid, platinum salts of a different constitu- tion would be formed. For this purpose 1 grm. of the new solid base was treated with 10 cub. centims. of strong hydrochloric acid, it dissolved with effervescence as if carbonic anhydride had been absorbed ; the solution took place with moderate readiness; it was filtered and treated with solution of platinum as before, a buff coloured precipitate was obtained; at this point 10 cub. centims. more hydrochloric acid were added, the precipitate became smaller, 25 cub. centims. more hydrochloric acid were added at this stage, and the solution was heated to about 90° and filtered; much of the platinum salt remained on the filter, and, after drying, gave 23°92 per cent. of platinum, the mother-liquid on cooling gave another precipitate containing 24°55 per cent. of platinum; both these pre- cipitates appear, therefore, in spite of the great excess of acid in which they were formed, to be constituted like the second precipi- tates previously obtained. The solid yellow base contained 3°06 per cent. of ash, which con- sists of carbonate of lime with a trace of iron, both derived from the chemicals used in its preparation. The solid base when heated fuses to a yellow oil, giving off pre- cisely the same odour as chinoline compounds generally; near a red heat it boils away leaving some carbon which, contrary to the usual rule in such cases, burns away readily. Nitric acid dissolves the base easily, giving a reddish brown solu- tion which on dilution with water affords a yellow precipitate; ammonia turns the solution red, and partially dissolves the pre- cipitate. 1881.] — On the Action of Sodium upon Chinoline. d41 Preparation of the Platinwm Salt from the Scarlet Hydrochlorate of Dichinoline. The scarlet hydrochlorate of dichinoline was dissolved in boiling water, and precipitated while boiling by an excess of platinic chloride. The high temperature of the solution was necessary to prevent the precipitation of the hydrochlorate with the platinum salt. The latter was of a beautiful pale cadmium yellow colour. The filtrate on cooling yielded fine needles in extremely small quantity. The pre- cipitate contained 24°54 per cent. of platinum, and probably, there- fore, had the same composition as those before mentioned, containing the same or nearly the same amount of platinum. The needles con- tained 35°7 per cent. of platinum, and it is most likely that the presence of a small quantity of this salt was the cause of the high platinum in the first precipitate. A direct combination of dichinoline with platinic chloride— CBHI N?, PtCls, would require 33:11 per cent. of platinum, butit is not easy, as I have said before, to admit such a formula, when it is remembered that the precipitation took place in the presence of hydrochloric acid. A salt of the formula— 2(Cl8HUN2) HCL2PtCl, would require 35°66 per cent. of platinum, and would only differ from the salt— 2(C18H"*N?) HCI. PtCl*, before alluded to, and which contains 22°18 per cent. of platinum, by containing one more equivalent of platinic chloride. It must, however, be distinctly stated that the numbers in this paper are given provisionally, and that the subject is still under study. Presents, March 3, 1881. ‘Transactions. Hastbourne :—Natural History Society. Papers, 1879-80. 8vo. The Society. Hdinburgh :—Geological Society. Transactions. Vol. III. Part 3. 8vo. Hdinburgh 1880. The Society. Scottish Meteorological Society. Journal. New Series. Nos. 55-59. 8vo. Hdinburgh. The Society. Glasgow :—Philosophical Society. Proceedings. Vol. XII. No. 1. 8vo. Glasgow 1880. The Society. D42 ; Presents. [Mar. 3, Transactions (continued). Huddersfield :—Yorkshire Naturalists’ Union. The “ Naturalist.’’ Nos. 60-67. 8vo. Huddersfield 1880. The Union. Watford :—Hertfordshire Natural History Society and Field Club. - Transactions. Vol. Ii. Parts 7 and 8. New Series, Vol. I. Parts land 2. 8vo. Hertford 1880. The Society. Reports. | Cambridge (Mass.) :—Harvard College Observatory. Thirty-fifth Annual Report. 8vo. Cambridge 1881.. The Observatory. Melbourne :—Geological Survey of Victoria. Report of Progress. No. VI. 8vo. Melbourne 1880. ~ The Survey. Washington :—United States Commission of Fish and Fisheries. Part VI. Report of the Commissioner for 1878. 8vo. Wash- ington 1880. The Commission. United States Geographical and Geological Survey of the Rocky Mountain Region. Report on Geology of High Plateaus of © Utah. 4to. Washington 1880. With Atlas. The Survey- = Galloway (W.) fPenycraig Disaster. Evidence of Mr. Galloway. Svo. Cardiff 1881. The Author.. Joly (N. et E.) 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Bruzelles (1880 ]. The Author. eB]: Presents. 543 Presents, March 10, 1881. Transactions. Innsbruck :—Ferdinandeum fir Tirol und Vorarlberg. Zeitschrift. Folge 3. Heft 24. 8vo. Innsbruck 1880. The Ferdinandeum. K6nigsberg :—Physikalisch-6konomische Gesellschaft. Schriften. Jahrg. XVIII. Abth. 2. (with Maps) Jahrg. XIX, XX, XXI. Abth. 1. 4to. Konigsberg 1880. The Society. Leeds :—Philosophical and Literary Society. Annual Report, 1879- 80. 8vo. The Society. London :—Royal Asiatic Society. Journal, Vol. XIII, Part 1. 8vo. London 1881. The Society. Sanitary Institute of Great Britain. Calendar, 1881. 8vo. Lon- don 1880. The Institute. Victoria Institute. Journal of the Transactions. Vol. XIV. No. 56. 8vo. London 1881. The Institute. Manchester :—-Geological Society. Transactions. Vol. XVI. Parts 2 and 3. 8vo. Manchester 1880-81. ‘The Society. Observations and Reports. ; Cincinnati :—Observatory. Publications. No. 5. 8vo. Cincinnati 1879. The Observatory. 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Dublin :—Office of the Registrar-General. Weekly Return of Births and Deaths in Dublin, &c. 1880. Vol. XVIT. 8vo. Dublin 1881. Quarterly Return of Marriages, Births, and Deaths. Nos. 66-68. 8vo. Dublin. The Registrar-General for Ireland. Melbourne :—Office of the Government Statist. Statistical Register of the Colony of Victoria. Parts 7-9. Title and Index. The Government Statist. Office of the Minister of Mines. Reports of the Mining Sur- veyors, 30th September, 1880. folio. Melbourne. The Hon. the Minister of Mines. St. Petersburg :—Physikalisches Central-Observatorium. Annalen. Jahrg. 1879. Theil 1, 2. 4to. St. Petersburg 1880. The Observatory. Harnshaw (S.) The Doctrine of Germs, or the Integration of certain Partial Differential Equations which occur in Mathematical Physics. 8vo. Cambridge 1881. The Author. Moore (F.) The Lepidoptera of Ceylon. Part 2. 4to. London 1881. The Government of Ceylon. Mueller (F. von), F.R.S. Eucalyptographia. Decade VII. 4io. Melbourne 1880. The Author. Phillips (J. A.) On the Constitution and History of Grits and Sand- stones. 8vo. Note on the Occurrence of Remains of Recent Plants in Brown Iron-Ore. 8vo. [London 1881. ] The Author. INDEX to VOL. XXXI. ABNEY (W. de W.) and Lieut.-Colonel Festing on the influence of the mole- cular grouping in organic bodies on their absorption in the infra-red region of the spectrum, 416. Absorption, on ‘the influence of the -molecular grouping in organic bodies on their, in the infra-red region of the spectrum (Abney and Festing), 416. - Absorption spectra of cobalt salts, on the (Russell), 51. Actinometrical observations made in India at Mussooree and Dehra in Oc- tober and November, 1879 (Hen- nessey), 154. Action of organic substances on the ultra-violet rays of the spectrum: Part III (Hartley and Huntington), 1 Address of the President, 74. Aleurone grains, on the chemical compo- sition of (Vines), 59. Alopecia areata, on Bacterium decalvans : an organism associated with the de- struction of the hair in (Thin), 502. Altitude, experiments on the influence of, on respiration (Marcet), 418. Anniver sary meeting, 73. Ansted (David Thomas), i Atkinson (R. W.) on the diastase of — k6ji, 528. Auditors elected, 37. report of, 73. Azores, note on the determination of | magnetic inclination in the (Thorpe), 237. Baber (E. C.), researches on the minute structure of the thyroid gland, 279. Bacteria, on the absorption of pigment by (Thin), 503. Bacterium decalwans, on (Thin), 502. Bell (Graham) on methods of preparing selenium and other substances for photophonic experiments, 72. Beresford-Hope (A. J. B.), admitted, 59. . SY SESS A a Beryllium (glucinum), on the essential properties of (Nilson and Pettersson), 37. Bilirubin, account of the artificial pro- duction of the colouring-matters of human urine from (MacMunn), 206. Bimodular method, on an improved, of computing natural and tabular loga- rithms and anti-logarithms to twelve or sixteen places with very brief tables (Ellis), 381. Bottomley (J. T.), additional note to a paper ‘‘ On the thermal conductivity of water,” 300. Broun (J. A.) on gravimeters, with special reference to the torsion-gravi- meter designed by the late (Herschel), 317. Candidates for election, list of, 485. Capillary electroscope, phenomena of the (Gore), 295. Carnelley (T.), preliminary note on the existence of ice and other bodies in the solid state at temperatures far above their ordinary melting points, 284. Chinoline, on the action of sodium upon (Williams), 536. : Chlorobromiodides of silver, on the effects of heat on some (Rodwell), 291. Climates, on the secular inequalities in terrestrial, depending on the perihe- lion longitude and eccentricity of the earth’s orbit (Haughton), 473. Cobalt salts, on the absorption spectra of (Russell), 51. Cochlea of the Ornithorhynchus platypus compared with that of ordinary mam- _ mals and of birds (Pritchard), 149. Colour-blind, how do the, see the diffe- rent colours ? (Holmgren) 302. Colouring-matters of human urine, fur- ther researches into the (MacMunn), 206. Colours, revision of Newton’s table of (Reimold and Ricker), 524. 548 Conroy (Sir J.), some experiments on metallic reflexion: No. II, 486. Co-ordinates of a cubic curve in space, on the forty-eight (Spottiswoode), 301. Council, election of, 101. Critical point, on the (Ramsay), 194. Crookes (W.) on heat conduction in highly rarefied air, 239. onthe viscosity of gases at high exhaustions, 446. note by Professor Stokes on the re- duction of his experiments on the de- crement of the are of vibration of a mica plate oscillating within a bulb containing more or less rarefied gas, 458. Cubic curve, on the forty-eight co-ordi- nates of a, in space (Spottiswoode), 301. Darwin (G. H.) on the tidal friction of a planet attended by several satellites, and on the evolution of the solar sys- tem, 322. Definite integrals, on certain: No. VIIT (Russell), 330. Diastase of k6ji, on the (Atkinson), 523. Dielectric capacity of liquids (Hopkin- son), 347. Diffusion of liquids, influence of voltaic currents on the (Gore), 250. Dinosaur, Polacanthus Foxii, a large undescribed, from the Wealden for- mation in the Isle of Wight (Hulke), 336. Dixey (F. A.) on the ossification of the terminal phalanges of the digits, 63. Donation fund, account of grants from the, in 1879-80, 110. Earthquakes of July, 1880, at Manila, notes on the (Pauli), 460. Electric currents caused by liquid diffu- sion and osmose (Gore), 296. Electric distribution as manifested by that of the radicles of electrolytes, ex- perimental researches into (Tribe), 320. Electric osmose, experiments on (Gore), 253. Electrical resistance of thin liquid films, on the (Reinold and Riicker), 524. Electro-magnetic induction, molecular (Hughes), 525. Electroscope, phenomena of the capil- lary (Gore), 295. Electrostatic capacity of glass, the (Hop- kinson), 148. Ellis (A. J.) on an improved bimodular method of computing natural and tabular logarithms and anti-logarithms INDEX. to twelve or sixteen places with very brief tables, 381. Ellis (A. J.) on the influence of tem- perature on the musical pitch of harmonium reeds, 413. on the potential radix as a means of calculating logarithms to any re- quired number of decimal places, with a summary of all preceding methods chronologically arranged, 398. Errors of adjustment, on a method of destroying the effects of slight, in ex- periments of changes of refrangibility due to relative motions in the line of sight (Stone), 381. on a simple mode of elimi- nating, in delicate observations of compared spectra (Stokes), 470. Essential oils, an examination of, re- searches on the action of organic sub- stances on the ultra-violet rays of the spectrum: Part III (Hartley and Huntington), 1. Evolution of the solar system, cn the (Darwin), 322. Ewing (J. A.) on a new seismograph 440, Fellows deceased, 73. elected, 74. Festing (Lieut.-Col.) and W. de W. Abney on the influence of the mole- cular grouping in organic bodies on their absorption in the infra-red region of the spectrum, 416. Financial statement, 103-105. Fossil wood from the Mackenzie River, note on the microscopic examination of some (Schroter), 147. Friction of water against solid surfaces of different degrees of roughness, on the (Unwin), 54. Fund, donation, account of grants from the, 1879-80, 110. Government (4,000/.), account of appropriations from the, 111. Fungus of ringworm, on the (Thin), 501. Gamgee (Dr.), note on a communica- tion made to the Royal Society by Professor Roscoe, on the absence of potassium in protagon prepared by (Thudichum), 282. Ganglion cells, note on the occurrence of, in the anterior roots of the cat’s spinal nerves (Schafer), 348. Gas, note on the reduction of Mr. Crookes’s experiments on the decre- ment of the are of vibration of a mica plate oscillating within a bulb con- taining more or less rarefied, 458. INDEX. Gases, on the viscosity of, at high ex- haustions (Crookes), 446. Geology, notes on physical, No. VII (Haughton), 473. Gladstone (J. H.), the refraction equiva- lents of carbon, hydrogen, oxygen, and nitrogen in organic compounds, 327. (W. E.), elected, 301. Glass, the electrostatic capacity of (Hop- kinson), 148. Gore (G.) electric currents caused by liquid diffusion and osmose, 296. experiments on electric osmose, 253. — influence of voltaic currents on the diffusion of liquids, 250. on the thermo-electric behaviour of aqueous solutions with platinum electrodes, 244. phenomena of the capillary electro- scope, 290. Government fund (4,0002.), aecount of appropriations from the, 111. Government grant (1,000/.), account of the appropriation of, 110. Grant-Duff (Rt. Hon. M. E.), elected, 860; admitted, 416. Grants from the Donation Fund in 1879- 80, account of, 110. Gravimeters, with special reference to the torsion-gravimeter designed by the late J. Allan Broun, F.R.S. (Herschel), 317. Gray (Asa), admitted, 141. Hair, on Bacterium decalvans, an organ- ism associated with the destruction of the, in Alopecia areata (Thin), 502. Hannay (J. B.) on the limit of the liquid state, 520. Harmonic ratios in the spectra of gases, on (Schuster), 337. Harmonium reeds, on the influence of temperature on the musical pitch of (Ellis), 413. Hartley (W. N.) and A. K. Huntington, researches on the action of organic substances in the ultra-violet rays of the spectrum. Part III. An exami- nation of essential oils, 1. Haughton (Rey. 8.), notes on physical geology: No. VII. On the secular inequalities in terrestrial climates de- pending on the perihelion longitude and eccentricity of the earth’s orbit, 473. Haycraft (J. B.) upon the cause of the striation of voluntary muscular tissue, 360. Heat, action of an intermittent beam of VOL. XXXi. 549 radiant, upon gaseous matter (Tyndall), 307. Heat, further experiments on the action of an intermittent beam of radiant, on gaseous matter. Thermometric measurements (Tyndall), 478. Heat, on the effects of, on the chloride, bromide, and iodide of silver, and on some chlorobromiodides of silver, (Rodwell), 291. Heat conduction in highly rarefied air, on (Crookes), 239. Hennessey (J. B. N.) on actinometrical observations made in India at Mus- sooree and Dehra in October and November, 1879, 154. Herschel (Major J.) on a simplified form of the torsion-gravimeters of Broun and Babinet, 141. on gravimeters, with special refer- ence to the torsion-gravimeter de- signed by the late J. Allan Broun, E_R.S., 317. Hicks (W. M.) on toroidal functions, 504. High power definition, microscopical researches in (Royston-Pigott), 260. Holmgren (Frithiof), how do the colour- blind see the different colours? In- troductory remarks, 302. Hopkinson (J.), dielectric capacity of hquids, 347. —— the electrostatic capacity of glass, 148. Heematin, account of the artificial pro- duction of the colouring-matters of human urine from (MacMunn), 206. Hughes (D. E.), molecular electro- magnetic induction, 525. Hulke (J. W.), Polacanthus Foxti, a large undescribed Dinosaur from the Wealden formation in the Isle of Wight, 336. Huntington (A. K.) and W. N. Hartley, researches on the action of organic substances on the ultra-violet rays of the spectrum: Part III. An exami- nation of essential oils, 1. Ice, preliminary note on the existence of, in the solid state at a temperature above its ordinary melting point, (Carnelley), 284. Immature ovarian ovum, note to the paper on the structure of the, in the common fowl and in the rabbit (Schafer), 282. Induction, molecular electro-magnetic (Hughes), 525. Influence of altitude on respiration, experiments on the (Marcet), 418. Intermittent beam of radiant heat, 2Q 590 action of an, upon gaseous matter (Tyndall), 307. Intermittent beam of radiant heat, further experiments on the action of an, on gaseous matter. Thermome- tric measurements (Tyndall), 478. Tron lines widened in solar spots, on the (Lockyer), 348. Jessel (Sir G.), elected, 59; admitted, 301. Kew Committee, report of the, 115. Koji, on the diastase of (Atkinson), 523. Land-lizard, description of some remains of the gigantic, from Australia: Part III (Owen), 380. Lassell (William), obituary notice of, vil. Limerick (Bishop of), admitted, 141. Liquid diffusion and osmose, electric currents caused by (Gore), 296. Liquid films, on the electrical resistance of thin (Reinold and Riicker), 524. Liquid state, on the limit of the (Han- nay), 520. Liquids, dielectric capacity of, 347. Lloyd (Rey. H.), obituary notice of, xxi. Lockyer (J. N.) on a sun-spot observed August 31, 1880, 72. — on the iron lines widened in solar spots, 348. Logarithms and anti-logarithms, on an improved bimodular method of com- puting natural and tabular, to twelve or sixteen places with very brief tables (Ellis), 381. Logarithms, on the potential radix as a means of calculating (Ellis), 398. MacMunn (C. A ), further researches into the colouring matters of human urine, with an account of their artificial pro- duction from bilirubin, and from hematin, 206. researches into the colouring- matters of human urine, with an ac- count of the separation of urobilin, 26. Magnetic inclination, note on the deter- mination of, in the Azores (Thorpe), 237. Marcet (W.), experiments undertaken during the summer, 1880, at Yvoire, Courmayeur, and the “ Col de Géant,”’ on the influence of altitude on respira- tion, 418. Medals, presentation of the, 95. Megqaiania prisca, description of some remains of, Part III (Owen), 380. Melting-points, preliminary note on the a nn INDEX. existence of ice and other bodies in the solid state at temperatures far above their ordinary (Carnelley), 284. Metallic reflexion, some experiments on, No. IT (Conroy), 486. Microscopical researches in high power definition (Royston-Pigott), 260. Miller (William MHallowes), obituary notice of, il. Minute anatomy of the thymus, further note on the (Watney), 326. Molecular electro-magnetic (Hughes), 525. Molecular grouping in organic bodies, on the influence of the, on their absorp- tion in the infra-red region of the spectrum (Abney and Festing), 416. Molecular heat and volume of the rare earths and their sulphates (Nilson and Pettersson), 46. Muscular tissue, upon the cause of the striation of voluntary (Haycraft), 360. Musical pitch of harmonium reeds, on the influence of temperature on the (Ellis), 413. induction Newton’s table of colours, revision of (Reinold and Ricker), 524. Nilson (lL. F.) and Otto Pettersson on the essential properties and chemical character of beryllium (glucinum), 37. on the molecular heat and volume of the rare earths and their sulphates, 46. Obituary notices of Fellows deceased :— Anusted, David Thomas, 1. Lassell, William, vii. Miller, William Hallowes, ii. Sharpey, William, x. Stenhouse, John, xix. Lloyd, Rev. Humphrey, xxi. Occurrence of ganglion cells in the ante- rior roots of the cat’s spinal nerves, note on the (Schafer), 348. Officers, election of, 101. Organic compounds, the refraction equi- valents of carbon, hydrogen, oxygen, and nitrogen in (Gladstone), 327. Ornithorhynchus plitypus, cochlea of the, compared with that of ordinary mam- mals and of birds (Pritchard), 149. Osmose, electric currents caused by liquid diffusion and (Gore), 296. Ossification of the terminal phalanges of the digits, on the (Dixey), 63. Ovarian ovum in the common fowl and in the rabbit, note to the paper on the structure of the immature (Schafer), 282. Owen (R.), description of some remains of the gigantic land-lizard (Megalania INDEX. prisca, Owen) from Australia, Part III, 380. Pauli (W. B.), notes on the earthquakes of July 1880, at Manila, 460. Pettersson (Otto) and L. F. Nilson, on the essential properties and chemical character of beryllium (glucinum), 37. on the molecular heat and volume of the rare earths and their sulphates, 46. Photophonic experiments, on methods of preparing selenium and other sub- stances for (Bell), 72. Physical geology, notes on, No. VII (Haughton), 473. Pigment, on the absorption of, by bac- teria (Thin), 503. Placentation of the racoon (Watson), 325. Planet, on the tidal friction of a, attended by several satellites (Darwin), 322. Platinum electrodes, on the thermo- electric behaviour of aqueous solutions with (Gore), 244. Polacanthus Foxii, a large undescribed Dinosaur from the Wealden formation in the Isle of Wight (Hulke), 336. Potential radix, on the, as a means of calculating logarithms to any required number of decimal places, with a sum- mary of all preceding methods, chro- nologically arranged (Ellis), 398. Preece (W. H.) on the conversion of radiant energy into sonorous vibra- tions, 506. Presentation of the medals, 95. Presents, lists of, 138, 257, 350, 479. President’s address, 74. Pritchard (U.), the cochlea of the Or- mithorhynchus platypus compared with that of ordinary mammals and of birds, 149. Procyon lotor, on the female organs and placentation of the (Watson), 325. Protagon, note on a communication made to the Royal Society by Professor Roscoe on the absence of potassium in, prepared by Dr. Gamgee (Thudi- chum), 282. Racoon (Procyon lotor), on the female organs and placentation of the (Wat- son), 325. Radiant energy, on the conversion of, into sonorous vibrations (Preece), 506. Radiant heat, action of an intermittent beam of, upon gaseous matter (Tyn- dall), 307. turther experiments on the action of an intermittent beam of, on | 501 gaseous matter, thermometric mea- surements (Tyndall), 478. Ramsay (W.) on the critical point, 194. Rare earths and their sulphates, on the molecular heat and volume of the (Nilson and Pettersson), 46. Rarefied air, on heat conduction in highly (Crookes), 239. Reflexion, some experiments on metallic, No. Il (Conroy), 486. Refraction equivalents, the, of carbon, hydrogen, oxygen, and nitrogen in organic compounds (Gladstone), 327. Refrangibility, on a method of destroy- ing the effects of slight errors of ad- justment in experiments of changes of, due to relative motions in the line of sight (Stone), 381. Reinold (A. W.) and A. W. Riicker on the electrical resistance of thin liquid films, with a revision of Newton’s table of colours, 524. Respiration, experiments on the influence of altitude on (Marcet), 418. Reynolds (J. E.), admitted, 524. Ringworm, on the fungus of (Thin), 501. Roscoe (Professor), note on a communi- cation made to the Royal Society by (Thudichum), 282. Royston-Pigott (G. W.), microscopical researches in high power definition, 260. Riicker (A. W.) and A. W. Reinold on the electrical resistance of thin liqui'l films, with a revision of Newton’s table of colours, 524. Russell (W. H. L.) on certain definite integrals, No. VIII, 330. (W. J.) on the absorption spectra of cobalt salts, 51. Schafer (KH. A.), note on the occurrence of ganglion cells in the anterior roots of the cat’s spinal nerves, 348. note to the paper on the structure of the immature ovarian ovum in the common fowl and in the rabbit, 282. Schréter (C.), note on the microscopic examination of some fossil wood from the Mackenzie River, 147. Schuster (A.) on the harmonic ratios in the spectra of gases, 337. Secular inequalities in terrestrial cli- mates, on the, depending on the peri- helion longitude and eccentricity of the earth’s orbit (Haughton), 473. Seismograph, on a new (Hwing), 440. Selenium, on methods of preparing, for photophonic experiments (Bell), 72. Sharpey (William), obituary notice of, x. Silver, on the effects of heat on the chloride, bromide, and iodide of, and aa Ver 02 on some chlorobromiodides of (Rod- well), 291. Sodium, on the action of, upon chino- line (Williams), 536. Solar system, on the evolution of the (Darwin), 322. spots, on the iron lines widened in (Lockyer), 348. Sonorous vibrations, on the conversion of radiant energy into (Preece), 506. Spectra, on the absorption of cobait salts (Russell), 51. on a simple mode of eliminating errors of adjustment in delicate obser- vations of compared (Stokes), 470. of gases, on harmonic ratios in the (Schuster), 337. Spectrum, action of organic substances on the ultra-violet rays of the. Part III. An examination of essential oils (Hartley and Huntington), 1. on the influence of the molecular grouping in organic bodies on their absorption in the infra-red region of the (Abney and Festing), 416. Spinal nerves, note on the occurrence of ganglion cells in the anterior roots of the cat’s (Schafer), 348. Spottiswoode (W.) on the 48 eo-ordi- nates of a cubic curye in space, 301. Stenhouse (John), obituary notice of,. X1Xx. Stokes (G. G.), note on the reduction of Mr. Crookes’s experiments on the decrement of the are of vibration of a mica plate oscillating within a bulb containing more or less rarefied gas 458. on a simple mode of eliminating errors of adjustment in delicate obser- vations of compared spectra, 470. Stone (E. J.) on a method of destroying the effects of slight errors of adjust- ment in experiments of changes of refrangibility due to relative motions in the line of sight, 381. Striation of voluntary muscular tissue, upon the cause of the (Haycraft), 360. Sun-spot, on a, observed August 31, 1880: (Lockyer), 72. Temperature, on the influence of, on the musical pitch of harmonium reeds (Ellis), 413. Terminal phalanges of the digits, on the ossification of the (Dixey), 63. Thermal conductivity of water, addi- tional note to a paper on the (Bot- tomley), 300. Thermo-electric behaviour of aqueous | | \ INDEX. solutions with platinum electrodes, on the (Gore), 244. Thin (G.) on Bacterium decalvans ; au organism associated with the destruc- tion of the hair in Alopecia areata, 502. Thin (G.) on the absorption of pigment by bacteria, 503. on the Trichophyton tonsurans (the fungus of ringworm), 501. Thorpe (T. E.), note on the determina- tion of magnetic inclination in the Azores, 237. Thudichum (J. L. W.), note on a com- munication made to the Royal Society by Professor Roscoe, on the absence of potassium in protagon prepared by Dr. Gamgee, 282. Thymus, further note on the minute anatomy of the (Watney), 326. Thyroid gland, researches in the minute structure of the (Baber), 279. Tidal friction of a planet attended by several satellites (Darwin), 322. Toroidal functions, on (Hicks), 504. Torsion-gravimeters of Broun and Babinet, on a simplified form of the (Herschel), 141. designed by the late J. Allan Broun, on gravimeters with special reference to the (Herschel), 317. Tribe (Alfred), experimental researches into electric distribution as manifested by that of the radicles of electrolytes, 320.. Trichophyton tonsurans, on the (Thin), 501. Trust funds, 106-10. Tyndall (J.), action of intermittent beam of radiant heat upon gaseous matter, 307. further experiments on the action of an intermittent beam of radiant heat on gaseous matter ; thermometric measurements, 478. Ultra-violet rays of the spectrum, action of organic substances on the, Part III. An examination of essential oils (Hartley and Huntington), 1. Unwin (W. C.) on the friction of water against solid surfaces of different degrees of roughness, 54. Urine, researches intv the colouring- matters of human (MacMunn), 26. further researches into the colour- ing-matters of human (MacMunn), 206. Urobilin, account of the separation of (MacMunn), 26. Vice-Presidents appoimted, 141. INDEX. Vines (S. H.) on the chemical composi- tion of aleurone-grains, 59. Viscosity of gases at high exhaustions, on the (Crookes), 446. Voltaic currents, influeuce of, on the diffusion of liquids (Gore), 250. Water, additional note to a paper on the thermal conductivity of (Bottomley), 300. Dd3 Watney (Herbert), further note on the minute anatomy of the thymus, 326. Watson (M.) on the female organs and placentation of the racoon (Procyon lotor), 325. Wealden formation in the Isle of Wight, a large undescribed Dinosaur from the (Hulke), 336. Wilhams (C. G.) on the action of sodium upon chinoline, 436. END OF THE THIRTY-FIRST YOLUME. TY SOM ks hae a , } an f ry i al { pene og eae fi a ; : lig 1 Ay ih: i La " i . i } A ¢ i » PROCEEDINGS OF THE ROYAL SOCIETY. Gh. XX I; No. 206. CONTENTS. PAGE. Researches on the Action of Organic Substances on the Ultra-Violet Rays of the Spectrum. Part III. An Examination of Essential Oils. By W. N. Harrttey, F.R.S.E., &c., Professor of Chemistry in the Royal College of Science for Ireland, Dublin, and A. K. Breit e F.C.S., Associute of the Royal School of Mines L Researches into the Colouring-matters of Human Urine, with an Account 0% the Separation of Urobilin. By Cuas. A. MacMuny, B.A.,M.D. . . 26 Obituary Notices :— Davip THomas ANSTED . : oS i Wittiku Hattowes Miner. . .« (Antz. - +2 > ii | ee Price Two Shillings. PHILOSOPHICAL TRANSACTIONS. Contents oF Part I, 1880. I. On the Determination of the Rate of Vibration of Tuning-Forks. By HERBERT M‘Lzop, F.C.S., and Grorcr SYDENHAM CrLARE®, Lieut, R.E., Royal Indian Engineering College, Cooper’s Hill. II. The Contact Theory of Voltaic Action—Paper No. III. By Professors W. HE. Ayrton and JoHN PERRY. III. Researches on the Comparative Structure of the Cortex Cerebri. By W. Bevan Lewis, L.R.C.P. (Lond.), Senior Assistant Medical Officer, West Riding Lunatic Asylum, Wakefield. IV. Experimental Researches on the Electric Discharge with the Chloride of Silver Battery. By Warren Der La Roz, M.A., D.C.L., F.RS., and Hueco W. Muir, Ph.D., F.R.S.—Part III. Tube Potential; Potential at a Constant Distance and Various Pressures; Nature and Phenomena of the Electric Are. V. On the Conduction of Heat in Ellipsoids of Revolution. By C.N IVEN, M.A., Professor of Mathematics in Queen’s College, Cork. VI. On some recent Improvements made in the Mountings of the Telescopes at Birr Castle. By the Ear. or Rosss, F.R.S. VII. Concluding Observations on the Locomotor System of Meduse. By GEORGE J. Romangs, M.A., F.LS. ; VIII. Researches on Explosives.—No. II. Fired Gunpowder. By Captain NoBLE (late R.A.), F.R.S., FLR.A.S., F.C.8., &., and F. A. Asst, C.B., E.R.S., V.P.CS., &e., &e. IX. English Repreduction Table. By Dr. W. Farr, F.R.S. X. Agricultural, Botanical, and Chemical Results of Experiments on the Mixed Herbage of Permanent Meadow, conducted for more than twenty years in succession on the same Land.—Part I. By J. B. Lawzs, LL.D., F.R.S., F.C.8., and J. H. GiuBert, Ph.D., F.R.S., F.C.S., F.LS. Index to Part I. PHILOSOPHICAL TRANSACTIONS. Part I, 1880, price £2 5s. Extra volume (vol. 168) containing the Reports of the Naturalists attached to the Transit of Venus Expeditions. Price £3. Sold by Harrison and Sons. Separate copies of Papers in the Philosophical Transactions, commencing with 1875, may be had of Triibner and Co., 57, Ludgate Hill. Vil an occasional visit to the Continent, either for duty or for relaxation. He delighted especially in the scenery of the dolomite mountains of the Italian Tyrol, spending among them many hours of quiet enjoy- ment, while their magnificent outlines were recorded with rare fidelity by the accomplished companion of his life. Happy, then, in his domestic life, happy in the affectionate appre- ciation of numerous friends of varied ages and ranks, he was also happy in seeing his work (though for honours and rewards he cared less than most men) not unacknowledged by his contemporaries. In addition to the honours mentioned above, he received in 1865 the degree of LL.D. from the University of Dublin, and in 1876 that of D.C.L. from Oxford. In 1870 he was awarded a Royal Medal by this Society. He was a Knight of the Order of St. Maurice and St. Lazare of Italy and of the Order of Leopold of Belgium. He was also an honorary member of the Royal Society of Edinburgh, of the Mineralogical Society of France, and of Boston, U.S.A., a foreign member of the Mineralogical Society of St. Petersburg, of the Imperial Royal Academy of Sciences, Vienna, and of the Royal Society, Gét- tingen; and a corresponding member of the Academies of Berlin, Munich, Paris, St. Petersburg, and of Turin. hae . ad ‘ uf - ~ . . + + ‘ : ' a 4 ra ¢ = 4 ; i — \ = rat ‘ : ‘ i : =" ' 2 ” ‘ ' \ > : . Sct ' > - ' ” 1 is 5 | ane i é = 3 . He GOVERNMENT GRANT OF £1000. A Meetine of the Government-Grant Committee will be held in February, 1881. Tt is requested that applications to be considered at that Meeting be forwarded to the Secretaries of the Royal Society, Burlington House, before the 31st December, 1880. GOVERNMENT FUND OF £4000 FOR THE PROMOTION OF SCIENTIFIC RESEARCH. A MerertiIne of the Government-Fund Committee will be held in February, 1881. It is requested that applications to be considered at that Meeting be forwarded to the Secretaries of the Royal Society, Burlington House, before the 31st of December, 1880. CATALOGUE OF SCIENTIFIC PAPERS, COMPILED BY THE ROYAL SOCIETY. Published by Her Majesty’s Stationery Office. 8 yols., 4to. 1800—1873. Per vol.: 20s., cloth ; 28s., half-morocco. On Sale by Murray, Albemarle Street, and Tribner and Co., Ludgate Hill. > = ge HARRISON AND SONS, 45 & 46, ST. MARTIN’S LANE, W.C.. AND ALL BOOKSELLERS. e PROCEEDINGS OF PoeoewOYAL SOCIETY VOL. XXXI. No. 207. CONTENTS. November 18, 1880. PAGE I. On the Essential Properties and Chemical Character of Beryllium (Glucinum). By L. F. Nizson and Orro PETTERsson : 37 II. On the Molecular Heat and Volume of the Rare Earths and their Sulphates. By L. F. Nizson and Orro PrrrEersson i : - 46 III. On the Absorption Spectra of Cobalt Salts. By W.J. Russrrz, Ph.D., F.R.S., Treas. C.S., Lecturer on Chemistry at the Medical School, St. | Bartholomew’s Hospital . . : : : : ; oe IV. On the Friction of Water against Solid Surfaces of Different Degrees of Roughness. By Professor W. C. Unwin, M.I1.C.E., Professor of Hydraulic Engineering at the Royal Indian Engineering College . d4 November 25, 1880. I. On the Chemical Composition of Aleurone-Grains. By 8. H. Vines, M.A., D.Sc., Fellow of Christ’s College, Cambridge II. On the Ossification of the Terminal Phalanges of the Digits. By F. A. Dixty, B.A. Oxon. (Plates 1, 2) : : : : : a Os IIT. On aSun-Spot observed August 31,1880. By J. N. Lockyer, F.R.S. . 72 TV. On Methods of Preparing Selenium and other Substances for Photo- phonic Experiments. By Professor GRAHAM BELL : “JI bo For continuation of Contents see 4th page of Wrapger. Price Four Shillings. Pa ee PHILOSOPHICAL TRANSACTIONS. OOD aaa ConTENTS OF Part IT, 1880. XI. Double Refraction and Dispersion in Iceland Spar: an Experimental In- vestigation, with a comparison with Huyghen’s Construction for the Extraordinary Wave. By R. T. GuazeBroox, M.A., Fellow of Trinity College, Cambridge. XII. On the Normal Paraffins—Part III. By C. ScnortemueEr, F.R.S., Pro- fessor of Organic Chemistry in Owens College, Manchester. XIII. On the Motion of Two Spheres in a Fluid. By W. M. Hicxs, M.A., Fellow of St. John’s College, Cambridge. XIV. On the Organization of the Fossil Plants of the Coal-Measures.—Part X. Including an Examination of the- supposed Radiolarians of the Car- boniferous Rocks. By W. C. Witttamson, F.R.S., Professor of Botany in Owens College, Manchester. XV. On the Relation between the Diurnal Range of Magnetic Declination and Horizontal Force, as observed at the Royal Observatory, Greenwich, during the years 1841 to 1877, and the Period of Solar Spot Frequency. By Wittiam Euis, F.R.A.S., Superintendent of the Magnetical and Meteorological Department, Royal Observatory, Greenwich. XVI. On the Sensitive State of Vacuum Discharges.—Part II. By Witrram SPoTtTiswooDE, D.C.L., LL.D., President of the Royal Society, and J. FLnercHER Movttoy, late Fellow of Christ’s College, Cambridge. XVII. Tut Baxerian LecturE.—On the Photographic Method of Mapping the least Refrangible End of the Solar Spectrum. By Captain W. pz W. — ABNEY, R.E., F.R.S. XVIII. On the Photographic Spectra of Stars. By Wintr1am Hueeins, D.C.L., LU.D., F.R.S. ' XIX. On the Electromagnetic Theory of the Reflection and Refraction of Light. By Geo. Fras. Firzceraup, M.A., Fellow of Trinity College, Dublin. XX. On the Secular Changes in the Elements of the Orbit of a Satellite revolv- ing about a Tidally Distorted Pianet. By G. H. Darwin, F.RB.S. Index to Part II. ; PHILOSOPHICAL TRANSACTIONS. Part II, 1880, price £2. Extra volume (vol. 168) containing the Reports of the Naturalists attached to the Transit of Venus Expeditions. Price £38. . Sold by Harrison and Sons. Separate copies of Papers in the Philosophical Transactions, commencing with 1875, may be had of Triibner and Co., 57, Ludgate Hill. OF THE EXACI A period of nez dorff's biographical a: work attracted the ; acknowledgment for 1 scientific publications ee eee | awn. antad he vali (80 "/gr 498) BOOLIy ‘(,(@yeUL Ip UU )puepte pe VLIL UL Ip BOTTISVE 99ST HES ‘aqqy — ‘Ul ‘skyd ‘warygo ‘uuy, ‘*sfyd ‘os ‘(gust ‘E£) “d OF vost (FL B ZL8T ‘69 8 99) “DSIO}U) .,, Wayo-TTeISA.1} “(oL-6981) “d FIT ‘opts “SULUJESUOTIUIVG =: met ‘d 6g ‘oT[ejoWlpaq weuegye ‘T7eyshry MZ ss198asQ * i (gL81) “d) | FUT) LOOPS efLoWost TE! Specimen of column af bon dans Vexpérience de Sur les phénoménes de deux rayons de lumiére d différences de marche (Ib sur la polarisation chrom 1850). Allein: Sur les la lumiére dans lair et 1854). De la chaleur pr de VYaimant sur les corp XLV, 1855). — Mit Do: aux démonstrations mi: rend. XVII, 1844). Mit nant Vaction des rayon: ques daguerriennes (Ib. ° interférences des rayons 1847). Allein: Sur w conique (Ib. id.) App a regulateur électromag 1849). Mit J. Regnault: ménes de la vision etc. (J monstration physique ¢ tation de la terre au m XXXII, 1851). Sur un expérimentale du mouve (Ib. XXXV, 1852). Sm rientation des corps toi un axe fixe a la surface Telescope en verre arg 1857). Nouv. polarisew Tortolini, Barn (1829), folgweise Prof. am »Collegio Urbano « (1834), Prof. d. »Int sublime« an d. rémisch Prof. d. »Calcolo sub (1838), auch Prof. am »Pontifico Seminai u. Mitgl. d. philosoph. (1845). Mitgl. d. Socie (Or.), geb. 1808, Nov. 1 Elementi di calcolo int Roma 1844. — Determi di alcune formole differ si trascenditi (Giorn. ar 1832). Teoria analitica pPnmal moar 1 Y lines A DICTIONARY OF THE EXACT SCIENCES, BIOGRAPHICAL AND LITERARY J. C. POGGENDORFF. CONTINUED AND COMPLETED. A period of nearly twenty years has elapsed since the time when Poggen- dorffs biographical and literary dictionary of the exact sciences appeared. That work attracted the notice of the whole scientific world and gained universal acknowledgment for the care with which the abundant matter, represented in the scientific publications of all ages and of all nations, was therein collected and supplemented by reliable biographical notes. A new generation of savants having since then sprung up, the former workers meanwhile still continuing their labours, it has become a work of ne- cessity to issue a supplement in continuation and completion of this important work, his difficult task has been undertaken by the undersigned. He has in his possession the material collected for the purpose by the late Poggendorft (+ 24 Jan, 1877), the editor of the ,,Annalen der Physik und Chemie“ during more than half a century, as well as a large accumulation of literary and biographical notes of his own. But he like his predecessor cannot for all that dispense with the assistance of all living authors whose names should appear in the work if the reliability and completeness aimed at is to be obtained. He will therefore, when occasion requires during the course of his labours, fake the liberty of submitting certain questions to his colleagues and begs of them to have the kindness to return the papers with the answers filled in to the address given below. ge The compiler need hardly say, that all communications respecting the life and works of deceased scientific authors will be received by him most gratefully, as well as all notices, even the most trifling ones, that may seem likely to com- plete or improve the main work. Leipzig, 1880. W. Feddersen, Dr. phil. Carolinenstr, 6. (Germany) Specimen-column of the main work. Specimen -column\ of the continuation. Foucault, Jean Bernard Léon, — Foucautlé, Jean Bern. Léon. — Seit Sohn eines Buchhindlers in Paris; seit 1845 | 1862 Astronom beim »Bureau des longi- Redactour d. wissenschaftl. Theils des Jour- | tudes« & phys. Assist. am Observatorium zu nal des Debats (Quérard, Lit. franc.) (Hé- | Paris, Mitgl.d. Paris. Ac. (Cosmos 20) (Compt. fer, N. biogr. gén.) (Or.), rend. 66) (London, R. Soc. Proc. 17). geb. 1819, Sept. 18, Paris. + 1868, Febr. 11, Paris (geb. 18/, 19). Mit Bolflolat-Lefdrre: De la préparation de la | Ferner: Recueil d. travaux scient., mis en ordre couche sensible qui doit recevoir Vimage de par Gariel, précedé dune notice par Ber- la chambre noire (Ann. chim. phys. Sér. WI, | trand, 624 p., 4°, Paris, 1878. I, TX, 1843). Procédé qui permet de repro- | Ann. chim. phys.: §. la lumiére de V’are vol- duire avee une égale perfection dans une image | taique, 3 p. (3) 58, 1860). Daguerrienne les tons brillants et les tons ob- Compt. rend.: Méth."* pour mesurer la vitesse scurs du modéle ({b. XIX, 1847). Mit Fizeau: | de la lumiére dans 1, milieux transpar., 7 p. Sur lintensité de la Iumidre émise par le char- | (30, 1850), - Emploi d. appareils d’induct. (In- over. * the original work. : Davy (Ib. XI, 1844). s interférences entre ans le cas de grandes . XXVI, 1849). Do et atique etc. (Ib. XXX, ; vitesses relatives de dans Yeau (Ib. XLI, oduite par linfluence s en mouvement (Ib. mé: Appareil destiné sxoscopiques (Compt. Fizeau: Obss. concer- ee sur les pla- XXIII, 1846). Sur les calorifiques (Ib. XXV, 1e horloge a pendule weil photo- you nétique (Ib. XXVIII, Sur autines phéno- b.id.). Allein: Dé- lu mouvement de ro- oyen du pendule (Ib. > nouv. démonstration ment de la terre ete. irnants entrainés par ie la terre etc. (Ib. id.). entée (Ib. XXXXIV, (Ib. XXXXV, 1857). aba. — Dr. Phil. d. mathemat. Physik li Propagande Fide« Universitat (1837), lime« an derselben . mathemat. Physik ‘io Romano« (1845) ~Collegiums in Rom ta Italiana seit 1846 9, Rom. initesimale, T. I, 8°, nazione we integrali anziali si algebriche e cadico di Roma, LVI, delle superficie gene- ‘les phénoménes d’o- | coduzione al Calcolo | Specimen of column of the continuation. terruptor”), 2 & 3 p. (42 & 4.3, 1856). — Téles- | cope“ en verre argenté, 3&2 p. (44 & 47, 1857 & 58). - Procédés* pour reconnaitre la config¢ur. d. surfaces opt., 1 p. (47). - Télescope parabol. en verre argenté, 2p. (49,1859). — Nouv. télese. de Pobservatoire imp., 22 p. (54, 1862). - Dé- term.” expér. de la vitesse de la lumiére, 6 p. (55, 1862). — Solution de Pisochronisme du pen- dule con.; conditions de Visochr., 1 & 2 p. (65 | & 57, id. & 63).—Modific. du moderateur de Watt, 2 p.— Mouvement d’un point oscill. cir- cul. s. u. surface de révol. de 2. ordre, 1 p. — Ré- aay de la lumiére électr., 1 p. (62, 1865). Moyen* * d’atfaiblir 1. rayons du soleil en foyer d. lunettes, 2 p. (6.3, 1866). -S. la construct. du plan opt., 1 p. (69, 1869). Cosmos: Recompos.” d. couleurs du spectre, 1 p. | (2, 1853). - Analyse prismat. & compos. de l’at- mosphere solaire, 4 p. (29, 1861). Genéve, Arch. se. phys.: S.* la conductibilité électr. propre d. liquides etc. 5,3 & 1 p. (24, 25 & 26, 1853 & 54). | Paris, Mém. de Vobsery.: Construction d. téles- re en verre argenté, 40 p. (5, 1859). ergl. Fizeau. Auch: 1 Pogg. Ann. Phys.; 2 Compt. rend.; 3 Phil. Mag.; 4 Carl, Rep. phys. Techn.; > Schlémilch, Ztschr. Math.; © Cosmos; * Astron. Soe. Month. Not. Topsoe, Haldor Frederic Axel. — Dr. phil. (Copenh. 1870). In Copenhagen: 1873 kénigi. Fabrik-Inspector, 1876 Prof. d. Chem. an d. héheren Militaérschule; Mitel. d. dort. Acad. seit 1877 (Or.), geb. 1842, Apr. 29, Skjelskér, Seeland. Krystall.-kemiske Underségelse om d. selensure Salte (Diss.), 70 p. Copenh. 1870. - Veiledning i d. kwalitat. Analyse, 2. Ed., 166 p. ib. 1878. Deutsche chem. Ges. Ber.: Hydrate d. Platinsaure | und platins. Ba, 3 p.—Darstell. & Gehalt d. wasserigen Bromwasserstofisiure, 4 p. (31870). Fresenius, Ztschr. analyt. Chem.: Zur Bestimm. v. Cl, Br & J verbunden mit Pt, 4 p. (9, 1869). Geneve, Arch. sc. phys.: Déterm. d. poids spécif. &d. volumes moléc. de diverssels, 4p. (£5, 1872). Kjébenhayn, Vidensk. Forh. Overs.: Krystall.- kem.* Underségelse over Dobbeltshaloidsalte af Pt, 59 p. (1868 & 69). - D&* over Chloriddobbel- salter af Pd, 4 p. (1870). - D2 over Doppelt- Platonitriter, 28 p. (1879). _ AISK. A ATLL. @ v Krvstal] Kiahenh. a.S --ODU.? UN- XIX ik plac But the effect of Dr. Sharpey’s teaching upon a large number of pupils did not proceed alone from the superiority of the information conveyed, or the implicit reliance which his pupils placed in the fulness, accuracy, and truthfulness of the statements of their teacher, but it was also due to, and greatly enhanced by, the feeling of friendly attachment, and even of filial affection amounting to reverence, which was inspired in the minds of the pupils by his uniform kindness, justice, and candour. In the other public offices held by Dr. Sharpey during the greater part of the time of his residence in London, the superior qualities of his mind had equal scope in conducing to the efficiency and usefulness of his services. As an examiner in the University of London and afterwards as a member of the Senate, as Secretary of the Royal Society, as Member of the General Medical Council, as one of the Science Commissioners and a trustee of the Hunterian Museum, his extensive knowledge, unbiassed judgment, and strict impartiality, while they gave weight to his opinions and suggestions, aided largely in the promotion of measures favourable to the interests of science and the public good. Of the more private features of Dr. Sharpey’s life and character it is difficult for those who have been most intimate with him to express their estimate in sufficiently moderate terms. While he was universally admired for the extent and accuracy of his acquirements and respected for the soundness of his judgment, he was not less esteemed and beloved for the gentleness of his disposition, the kindness of his heart, and the geniality of his nature. His powers of memory, naturally good, were carefully cultivated by the systematic turn of his mind and strengthened by exercise. His friends remember with delight the readiness with which, in the course of conversation, he could call up a desiderated quotation, or supply a fact on some doubtful point in history, philosophy, or science, or tell humorously some anec- dote which was equally apposite and amusing. He had nota single enemy, and he numbered among his friends all those who ever had the advantage of being in his society. Specimen of column of the original work. Vexpérience de Davy (Ib. XT, 1844). Ser ee phon aac des interférences entre denx rayons de Inmiere dans le cas de grandes différences de marche (Ib. XXVI, 1849). Do et sur la polarisation chromatique etc. (Ib, XXX, 1850), Allein: Sur les vitesses relatives de la lumiére dans Yair et dans Yean (Ib. XLI, 1854). De la chaleur produite par Vinfluence de Vaimant sur les corps en mouvement (Ib. XLV, 1855). — Mit Donné: Appareil destiné aux démonstrations Microscopiques (Compt. rend, XVIII, 1844). Mit Fizeau: Obss. concer- nant Vaction des rayons rouges sur les pla- ques daguerriennes (Ib. XXIII, 1846). Sur les interférences des rayons calorifiques (Ib. XXV, 1847), Allein: Sur une horloge a pendule conique (Ib. id.) Appareil photo - électrique a regulateur électromagnétique (Ib. XXVIII, 1849), Mit J. Regnault: Sur quelques phéno- menes de la vision ete. (Ib. id.). Allein: Dé- monstration physique du mouvement de ro- tation de la terre au moyen du pendule (Ib. XXXUJ, 1851). Sur une nouy. démonstration expérimentale du mouvement de la terre ete. (ib. XXXV, 1852). Sur les phénoménes d’o- rientation des corps tournants entrainés par nn axe fixe A la surface de la terre ete. (Ib. id.). Telescope en verre argentée (Ib. XXXXIV, 1857). Nouv. polariseur (Ib. XXXXV, 1857). Tortolini, Barnaba. — Dr. Phil. (1829), folgweise Prof. d. mathemat. Physik am »Collegio Urbano di Propagande Fide« (1834), Prof. d. »Introduzione al Calcolo snblime« an d. rémisch. Universitat (1837), Prof. d. »Caleolo sublime« an derselben (1838), auch Prof. d. mathemat. Physik am »Pontifico Seminario Romano« (1845) u, Mitgl. d. philosoph. Collegiums in Rom (1845). Mitgl. d. Societa Italiana seit 1846 (Or.), geb. 1808, Noy. 19, Rom. Klementi di caleolo infinitesimale, T. 1, 8%, Roma 1844. — Determinazione degl’ integrali di aleune formole differenziali si algebriche e si trascenditi (Giorn. arcadico di Roma, LVI, 1882). Teoria analitica delle superficie gene- rate dal moto di un linea ete. (Ib. LVI, 1882). Ricerche sopra aleuni punti di geometria ana- litica (Tb. LIX, 1888 et LXII, 1834). Trattata del calcolo dei residui (Ib. LXTIH, 1884—35 et LXVU, 1886). Quadratura dell’ellissoide a tre assi ineguali (Ib. LXXVIIT, 1839). Aleune ap- plicazioni del metodo inverso delle tangenti (Ib. LXXIX, 1839). Sopra le trasformazioni e i valori di aleuni integrali definiti che si rife- riscono alle superficie e solidita dei volumi (Ib, LXXX, 1889 et LAXXU, 1840). Sui limiti di aloune espressioni imaginarie (Ib. LXXXVI, 1841). Mem. sull’applicazione del calcolo de’ residui all’integrazione delle equazioni lineari a differenze finite (Ib. XC, XCI et XCI, 1842). Do allintegrazione delle equazioni lineari a de- rivate parziali (Ib. XCTIT, 1842; XCIV et XCV, 1843). Sul passaggio dagl'integradi delle equa- Specimen of column of the continuation. terruptor “),2 & 3 p. (42 & 4.3, 1856). - Téles- cope” en verre argenté, 3&2 p. (44 & £7, 1857 & 58). — Procédés* pour reconnaitre la configur. d. surfaces opt., 1 p. (#7).- Télescope parabol. en verre argenté, 2 p. (49,1859). — Nouv. télese. de Yobservatoire imp., 22 p. (54, 1862). - Dé- term.” expér. de la vitesse de la lumiére, 6 p. (55, 1862). — Solution de Pisochronisme du pen- dule con.; conditions de Visochr., 1 & 2 p. (65 & 57, id. & 63).—Modific. du moderateur de Watt, 2 p.— Mouvement d’un point oscill. cir- cul. s. n. surface de révol. de 2. ordre, 1 p. — Ré- gulateur* de la lumiére électr., 1 p. (67, 1865). Moyen** d’affaiblir 1. rayons du soleil en foyer d. lunettes, 2 p. (6-3, 1866). -S. la construct. du plan opt., 1 p. (69, 1869). Cosmos: Recompos.” d. couleurs du spectre, 1 p. (2, 1853). - Analyse prismat. & compos. de I’at- mosphére solaire, 4 p. (79, 1861). Genéve, Arch. sc. phys.: S.* la conductibilité électr. propre d. liquides ete, 5,3 & 1 p. (24, 25 & 26, 1853 & 54). Paris, Mém. de Vobsery.: Construction d. téles- copes en verre argenté, 40 p. (5, 1859). Vergl. Fizeau. Auch: + Pogg. Ann. Phys.; * Compt. rend.; * Phil. Mag.; * Carl, Rep. phys. Techn.; © Schlémilch, Ztschr. Math.; ® Cosmos; * Astron. Soc, Month. Not. Topsoe, Haldor Frederic Axel. — Dr. phil. (Copenh. 1870). In Copenhagen: 1873 koénigl. Pabrik-Inspector, 1876 Prof. d. Chem. an d. héheren Militirschule; Mite. d. dort. Acad. seit 1877 (Or.), geb. 1842, Apr. 29, Skjelskér, Seeland. Krystall.-kemiske Underségelse om d. selensure Salte (Diss.), 70 p. Copenh. 1870. - Veiledning i d. kwalitat. Analyse, 2. Ed., 166 p. ib. 1878. Deutsche chem. Ges. Ber.: Hydrate d. Platinsiure und platins. Ba, 3 p.—Darstell. & Gehalt d. Wisserigen Bromwasserstofisiiure, 4 p. (-3,1870). Fresenius, Ztschr. analyt. Chem.: Zur Bestimm. vy. Cl, Br & J verbunden mit Pt, 4 p. (9, 1869). Genéyve, Arch. sc. phys.: Déterm. d. poids spécif. &d. volumes moléce. de divers sels, 4 p. (45, 1872). Kjébenhayn, Vidensk. Forh. Oyers.: Krystall.- kem.” Underségelse over Dobbeltshaloidsalte af Pt, 59 p. (1868 & 69). - D&* over Chloriddobbel- salter af Pd, 4 p. (1870). - D2 over Doppelt- Platonitriter, 28 p. (1879). Kjébenh. Vid. Selsk. Afbandl. : Krystall,-opt.e Un- derség. med Hensyn til isomorfe Stoffer (mit C. Christiansen) 147 p. (1878). Stockholm, Ak. Handl. Ofvyers.: Zur krystall. Kenntniss d. Salze d. seltenen Erdmetalle, 39 p. (Bihang 2, 1874). Tidskr. for Phys. & Chem.: Sammensiitning, Krystalform & Viigtfylde, 114 p. (1869-70). Wien, Ak. Sitz.-Ber.: Krystall.-chem.” Untersu- chungen, 42 & 26 p. (66 & 69, 1872 & 74), 2 an kiinstlichen Salzen 40 p. (7:3, 1876), Auch: 'Genadve, Arch. sc, phys.; *Ann. chim. phys. Tortolini, Barn. — Abbé; seit 1866 »Canonico tit.“ an d. Basilica di San Maria ad Martyr; zuletzt gichtleidend(Ann. di mat.(2)7), +1874, Aug. 24, Ariccia (geb. %/,, 08). ‘ . : i 7] i ‘ 4, is / ue oe ‘ iz <4 \ en { ’ 1 rn 4 5 ‘ ¥ mi t : a ui be 1 se Axis f oT ‘ x 5 t “ F i } oy j i 4 ‘ bf a z 4 ast . =e -_ 4 r . ro W ‘ P Gorn, LED. E.R.S. z leet : ; . 295 VII. Electric Currents caused by Lig Diffusion and Osmose. By G. Gore, LL.D., F.R.S. : : . 296 VIII. Additional Note to a Paper “ On the Thermal Conductivity of Water.’ By J. T. Borromiey, Lecturer in Natural Philosophy, and Demon- _ strator in Experimental Physics in the University of Glasgow . . 800 January 18, 1881. I. On the 48 Co-ordinates of a Cubic Curve in Space- By Witir1am Spottiswoopk, M.A., D.C.L., President R.S.. : E : . 801 II. How do the Colour-blind See the different Colours? Introductory Remarks. By FRITHIOF HoLM@REN, Professor of ere Uni- versity, Upsala . : : - 302 III. Action of an Intermittent feean of Radhane Heats oe Gaseous Matter. By JOHN TYNDALL, F:R.S. : ; s : ae e3 (017) For continuation of Contents see 4th page of Wrapper. Price Two Shillings and Sixpence. PHILOSOPHICAL TRANSACTIONS. ConTENTS OF Part ITI, 1880. XXI. A Memoir on the Single and Double Theta-Functions. By A. CayLezy, F.R.S., Sadlerian Professor of Pure Mathematics in the University of Cambridge. XXII. Revision of the Atomic Weight of Aluminium. By J. W. Matzet, F.RS., Professor of Chemistry in the University of Virginia. XXIII. Description of some Remains of the Gigantic Land-Lizard (Wegalania prisca, Ow EN), from Australia.—Part II. By Professor OwEn, C.B., F.RS., &e. | XXIV. On the Ova of the Echidna Hystriz. By Professor OWEN, C.B., F.R.S., &e. XXV. On the Deter mi nation of the Constants of the Cup Anemometer by Experi- ments with a Whirling Machine.—Part II. By T. R. Rozsrnson, D.D., FE.R.S., &e. XXVI. On the Dyn amo-electric Current, and on Certain Means to Improve its Steadiness. By C. Wittiam Sremens, D.C.L., F.R.S. Index to Part ITT. PHILOSOPHICAL TRANSACTIONS. Part ITI, 1880, price £ . Extra volume (vol. 168) containing the Reports of the Naturalists attached to the Transit of Venus Expeditions. Price £3. Sold by Harrison and Sons. Separate copies of Papers in the Philosophical Transactions, commencing with 1875, may be had of Triibner and Co., 57, Ludgate Hill. 1881. | Presents. 359 Transactions (continued). Toulouse :—Académie des Sciences. Mémoires. 8e série. Tome I. ler et 2e semestre. 8vo. Toulouse 1879. The Academy. Turin :—R. Accademia delle Scienze. Atti. Vol. XV. Disp. 1-8. 8vo. Torino 1879-80. The Academy. Utrecht :—Physiologisch Laboratorium der Utrechtsche Hooge- school. 3 Reeks. V. 3de Aflev. 8vo. Utrecht 1880. The Laboratory. Observations and Reports. Cadiz :—Observatorio de Marina de la Ciudad de San Fernando. Almanaque Nautico, 1881-82. 8vo. Madrid 1879-80. The Observatory. Madrid :—Observatorio. Observaciones Meteoroldgicas, 1876-78. Svo. Madrid 1878-79. The Observatory. Moscow :—Observatoire. Annales. Vol. VI. Livr. 2. Vol. VII. Livr. 1. 4to. Moscow 1880. The Observatory. Paris :—Bureau Central Météorologique. Annales, 1878. Partie ITI. Pluies en France. 4to. Paris 1880. The Bureau. Potsdam : — Astrophysikalisches Observatorium. Publicationen. Band I. 4to. Potsdam 1879. The Observatory. Simla :—Home, Revenue, and Agricultural Department. Review of the Report on the Operations of the Survey of India during 1878-79. Folio. The Department. Blomefield (Rev. Leonard) The Winter of 1878-79 in Bath, and Seasons following. 8vo. Bath 1880. The Author. Greig (John Kinloch) Bank Noteand Banking Reform. 8vo. London 1880. The Author. Phillips (Henry), Junr. Some recent Discoveries of Stone Imple- ments in Africa and Asia. 8vo. Notes upon a Denarius of Augustus Cesar. 8vo. 1880. The Author. Sakurai (J.) On Metallic Compounds containing Bivalent Hydro- carbon-Radicals. Part 1. 8vo. London [1880]. The Author. WO. XXXI, 2D O20 Os Society, a Fellow of the Institute of Chemistry, an honorary member of the Berlin Chemical Society, as also of the Philosophical Society of Manchester, and the Pharmaceutical Society of Great Britain. It will be evident from an inspection of the titles of the numerous papers (more than 100 in number) published by Dr. Stenhouse during the past forty years, in the Transactions and Proceedings of the Royal Society, the “ Journal of the Chemical Society,” ‘‘ Liebig’s Annalen,” and other scientific journals (either alone or in conjunction with Mr. C. E. Groves), that these for the most part relate to what may truly be called ‘‘ Organic Chemistry,” the chemistry of com- pounds found in organised bodies, so that his name will long be asso- ciated with numerous carbon compounds obtained from plants, and derivatives formed from them. Among all these he applied himself chiefly to the principles from the lichens, and made known the results in eighteen papers. One of his communications, published in 1880, is worth mention as it relates to “ Betorcinol,” a substance he had discovered some thirty-two years previously. It is but seldom that a chemist lives to complete'a work begun so long before. Although the eminence he attained in organic research is fully recognised, his contributions to our technical knowledge are not so generally known. He was the author of many ingenious and useful inventions in dyeing, waterproofing, sugar manufacture, and tanning ; but the greatest and most permanent benefit has been conferred by his application of the powerful absorbent properties of wood charcoal to disinfecting and deodorising purposes, which took the form of charcoal air-filters and charcoal respirators. Of Dr. Stenhouse’s personal character, those who knew him inti- mately could never speak too highly, his general conversation and fund of anecdote rendering him a most pleasant companion. His in- genuity and quick perception were remarkable, and this combined with his unflagging industry, and patience and resignation in great bodily suffering, enabled him to continue his scientific work with unabated vigour, even after the effects of paralysis prevented him from _per- forming experiments with his own hands. a a ig pc sp NS et a a he i a a a a 4 we if eae ma zeit CONTENTS (continued). January 20, 1881. PAGE TI. On Gravimeters, with special reference to the Torsion-Gravimeter de- signed by the late J. Allan Broun, F.R.S. By Major J. Herscuetn, R.E., F.R.S., Deputy-Superintendent of the Great Trigonometrical ~.- ‘Survey of India. : ; 2 : i : ; : : Bae! -STI. Experimental Researches into Electric Distribution as manifested by that of the Radicles of Electrolytes. By ALFRED geen aT (A Ome Lecturer on Chemistry in Dulwich College . 2 : ‘ . 320 III. On the Tidal Friction of a Planet attended by several icles and onthe Evolution of the Solar System. By G. H. Darwin, F.R.S. . 322 IV. On the Female Organs and Placentation of the Racoon (Procyon lotor). By M. Warsoy, M.D., Professor of Anatomy, Owens College, Manchester : y ; : : : d : ; : . 3825 V. Further Note on the Minute Anatomy of the Thymus. By HERBERT } Watney, M.A., M.D. Cantab. . 4 2 : : : ; . 326 January 27, 1881. I. The Refraction Equivalents of Carbon, Hydrogen, Oxygen, and Ni- trogen in Organic Compounds. By J. H. Guapstone, Ph.D., F.R.S. 327 II. On certain Definite Integrals. No.8. By W. H. L. Russert, F.R.S.. 330 III. Polacanthus Foxii, a large undescribed Dinosaur from the Wealden Formation in the Isle of Wight. By J. W. Hutxe,F.RS. . . 336 IV. On Harmonic Ratios in the aes of Gases. By ARTHUR SCHUSTER, PRD) HRS 5 . : : : : . 337 VY. Dielectric Capacity of Liquide By J. Hopriyson, F.R.S. . : . 347 VI. Note on the Occurrence of Ganglion Cells in the Anterior Roots of the Cat’s Spinal Nerves. By E. A. ScHAFER,F.R.S. . : 3 . 348 VII. On the Iron Lines widened in Bola Cee By J. Norman Lockyer, E.R.S. : : : : : ‘ : ; : . 348 Lists of Presents. : ; Aer . 3850 Obituary Notice :— JOHN STENHOUSE . : : ; : ; 2 ae CATALOGUE OF SCIENTIFIC PAPERS, COMPILED BY THE ROYAL SOCIETY. . Published by Her Majesty’s Stationery Office. 8 vols., 4to. 1800—1873. Per vol.: 20s., cloth ; 28s., half-morocco. On Sale by Murray, Albemarle Street, and Triibner and Co., Ludgate Hill. HARRISON AND SONS, 45 & 46, ST. MARTIN’S LANE, W.C.., AND ALL BOOKSELLERS. PROCEEDINGS OF Pee ROYAL SOCIETY. VOL. XXXI. i Grose No. 210. be fae 2 Gee CONTENTS.” Vay “SB February 3, 1881. ee PAGE I. Upon the Cause of the Striation of Voluntary Muscular Tissue. By JOHN Berry HaycrarFt, M.B., B.Sc., F.R.S.E., Senior Physiological Demonstrator in the University of Edinburgh. (Plate 5) . ; . 360 II. Description of some Remains of the Gigantic Land-lizard (Megalania prisca, OWEN) from Australia. Part ITI. ae Professor OWEN, C.B., E.R.S., &e. . : 380 III, Ona Method of coer the Effects of slight Errors of Canes in Experiments of Changes of Refrangibility due to Relative Motions in the Line of Sight. By E. J. Stone, F.R.S., Director of the Radcliffe Observatory, Oxford . : : : 381 TV. On an Improved Bimodular Method of computing Natural and Tabular Logarithms and Anti-Logarithms to Twelve or Sixteen Places with very brief Tables. By ALEXANDER J. Evuis, B.A., F.R.S., F.S.A. . . 3881 V. On the Potential Radix as a Means of Calculating Logarithms to any Required Number of Decimal Places, with a Summary of all Preceding Methods aes uaa zo ALEXANDER J. Eutis, B.A., Miss. HSA. : 2 Z k . 398 VI. On the Influence of mew agin on the Musical Pitch of Harmonium Reeds. By ALEXANDER J. Ennis, B.A., F.R.S., F.S.A. : : . 413 February 10, 1881. I, On the Influence of the Molecular Grouping in Organic Bodies on their Absorption in the Infra-red Region of the Spectrum. By Captain W. DE W. ABNEY, R.E., F.R.S., and Lieutenant-Colonel Festine, R.K. . 416 Ii. Experiments undertaken during the Summer, 1880, at Yvoire (1,230 feet), Courmayeur (3,945 feet), and the “Col de Géant”’ (11,030 feet), on the Influence of Altitude on ee - Witi1amM Marcet, M.D., F.R.S. ‘ . 418 IIT. On a New Seismograph. By J J. A. Ewine, B.Sc., F.R.S.E., Professor of Mechanical Engineering in the University of T sees J an : : . 440 For continuation of Contents see 4th page of Wrapper. Price Four Shillings. PHILOSOPHICAL TRANSACTIONS. DODO ConTENTS OF Parr III, 1880. XXI. A Memoir on the Single and Double Theta-Functions. By A. Cayury, F.R.S., Sadlerian Professor of Pure Mathematics in the University of Chaba XXII. Revision of the Atomic Weight of Aluminum. By J. W. Mauzet, F.R.S., Professor of Chemistry in the University of Virginia. XXIII. Description of some Remains of the Gigantic Land-Lizard (Megalania prisca, OWEN), , C.B., E.R.S., &e. XXIV. On the Ova of the Echidna Hystrix. By Professor Owen, C.B., F.R.S., &e. XXV. On the Determination of the Constants of the Cup Anemometer by Experi- ments with a Whirling Machine.—Part If. By T. R. Par SOn D_Ds E.R.S., &e. XXVI. On the Dynamo-electric Current, and on Certain Means to Improve its Steadiness. By C. Winniam Siemens, D.C.L., F.R.S. Index to Part ITI. PHILOSOPHICAL TRANSACTIONS. Part III, 1880, price £1 1s. I-xtra volume (vol. 168) containing the Reports of the Naturalists attached to the Transit of Venus Expeditions. Price £3. Sold by Harrison and Sons. Separate copies of Papers in the Philosophical Transactions, commencing with 1875, | may be had of Triibner and Co., 57, Ludgate Hill. 1881.] | Presents. @) <485 Presented by A. J. Ellis, F.R.S. (continued) :— Schron (L.) Table d’Interpolation pour le Calcul des Parties Pro- portionelles, &c. 8vo. Paris 1873. Steinhauser (A.) Kurze Hilfstafel zur bequemen Berechnung finfzehnstelliger Logarithmen. 8vo. Wien 1865. Wace (Rev. Henry) On the Calculation of Logarithms. 8vo. [London 1873. ] . s ) 3 Bs u t t } ; ns y i ‘ \ a é ) ‘ \ ; . - » ‘ r > ea he GaN) i Ee ce 4 Fe ate eee at’) CONTENTS (continued). February 17, 1881. I. On the Viscosity of Gases at High Exhaustions. By W1it11am Crooxzs, E.R.S. Note on the Reduction of Mr. Crookes’s Experiments on the Decrement of the Are of Vibration of a Mica Plate oscillating within a Bulb contain- ing more or less rarefied Gas. By Professor G. G. Stoxzs, Sec. B.S. . IL. Notes on the Earthquakes of July, 1880, at Manila. By Commander W. B. Pav, R.N., Her Britannic Majesty’s Consul at Manila . February 24, 1881. I. On a Simple Mode of Eliminating Errors of Adjustment in Delicate Observations of Compared Spectra. By Professor G. G. Sroxss, Sec. B.S... é é : : ‘ ; F : d : : II. Notes on Physical Geology. No. VII. On the Secular Inequalities in Terrestrial Climates depending on the Perihelion Longitude and Eccentricity of the Earth’s Orbit. By the Rev. Samvurn Haveurton, Professor of Geology in the University of Dublin . III. Further Experiments on the Action of an Intermittent Beam of Radiant Heat on Gaseous Matter. Thermometric Measurements, By J. TYNDALL, F.R.S. . Lists of Presents PAGE 446: 458. 460 470 473 478 479 CATALOGUE OF SCIENTIFIC PAPERS, COMPILED BY THE ROYAL SOCIETY. Published by Her Majesty’s Stationery Office. 8 vols., 4to. 1800—1873. Per vol.: 20s., cloth ; 28s., half-morocco. On Sale by Murray, Albemarle Street, and Triibner and Co., Ludgate Hill. HARRISON AND SONS, 45 & 46, ST. MARTIN’S LANE, W.C., AND ALL BOOKSELLERS. PROCEEDINGS OF THE ROYAL SOCIETY. MO. XX XI. oA No. 211. Ger C- — . we T / Po De ~, ae 45 , Ug j CONTENTS. Sw, one “’ DEPOS* March 3, 1881. List of Candidates for Election iE ie TIE. Some Experiments on Metallic Reflexion. No. II. By Sir Joun Conroy, Bart., M.A. ; On the Trichophyton tonsurans (the Fungus of Ee ae Pe GEORGE Tuin, M.D. ; : : : : : ‘ . On Bacterium decalvans : an Organism associated with the Destruction of the Hair in Alopecia areata. By Guorce Turn, M.D.. . On the Absorption of Pigment by Bacteria. By Grorer Turn, M.D. . . On Toroidal Functions. By W. M. Hicks, M.A., St. John’s College, Cambridge . Microscopical Researches in High Power Definition. Preliminary Note on the Beaded Villi of Lepidoptera-Scales as seen with a Power of 3,000 Diameters. By Dr. Royston-Pieort, F.R.S, March 10, 1881. . On the Conversion of Radiant Energy into Sonorous Vibrations. By Wittam Henry PREECE . On the Limit of the Liquid State. By J. B. Hannay, F.RS.E. . On the Diastase of Kéji.. By R. W. Atkinson, B.Sc. (Lond.), Pro- fessor of Analytical and Applied Chemistry in the University of Tokié, Japan ; 2 : ,; ; : : ‘ For continuation of Contents see 4th page of Wrapper. Price Two Shillings. 505 506 520 523 ! PHILOSOPHICAL TRANSACTIONS. ConTENTS oF Parr IIT, 1880. XXI. A Memoir on the Single and Double Theta-Functions. By A. Cayi@y, F.R.S., Sadlerian Professor of Pure Mathematics in the University of Cambridge. XXII. Revision of the Atomic Weight of Aluminum. By J. W. Mazer, F.RB.S., Professor of Chemistry in the University of Virginia. XXIII. Description of some Remains of the Gigantic Land-Lizard (Megalania prisca, OWEN), from Australia.—Part II. By Professor Own, C.B., E.R.S., Xe. XXIV. On the Ova of the Hchidna Hystrix. By Professor Owen, C.B., F.RBS., &e. XXV. On the Determination of the Constants of the Cup Anemometer by Experi- . ments with a Whirling Machine.—Part II. By T. R. Ropiysoy, D.D., E.R.S., &e. XXVI. On the Dynamo-electric Current, and on. Certain Means to Improve its Steadiness. By C. Witi1aAm Siemens, D.C.L., F.R.S. Index to Part ITI. PHILOSOPHICAL TRANSACTIONS. Part III, 1880, price £1 1s. Extra volume (vol. 168) containing the Reports of the Naturalists attached to the Transit of Venus Expeditions. Price £3. Sold by Harrison and Sons. Separate copies of Papers in the Philosophical Transactions, commencing with 1579, may be had of Tritbner and Co., 57, Ludgate Hill. CONTENTS (continued). I Af March 17, 1881. i PAGE I. On the Electrical Resistance of Thin Liquid Films, with a Revision of Newton’s Table of Colours. By A. W. Reryoup, M.A., Professor of Physics in.the Royal Naval College, Greenwich, and A. W. Rtcxrsr, - A M.A., Professor of Physics in the Yorkshire College, Leeds : . 524 II. Molecular Electro-Magnetic Induction. By Professor D. E. Hucuss, E.R.S. : : : ; , : : . 520 III. On the Action of Sodium upon Chinoline. By C. GREVILLE WILLIAMS, E.RBS. : : : : ; : : : ; . 536 List of Presents : : es ; : : . 54d Obituary Notice :— Rev. HUMPHREY LOYD . : E ; ; 2 : Y 2 2 ee Index ; é y 4 : : : 5 d ; ; : : . 547 Title and Contents. CATALOGUE OF SCIENTIFIC PAPERS, COMPILED BY THE ROYAL SOCIETY. Published by Her Majesty’s Stationery Office. . 8vols., 4to. 1800—1878. Per vol.: 20s., cloth ; 28s., half-morocco. On Sale by Murray, Albemarle Street, and Triitbner and Co., Ludgate Hiil. HARRISON AND SONS, 45 & 46, ST. MARTIN’S LANE, W.C., AND ALL BOOKSELLERS. vee Es ey f, et ite ee! é 1 it Say oI me ee SU eee re eet ok note eee Lt we ade Aaa ee trey | & Veter ler Reteene® ERA cere RR Mie bab be ot ow hh te Bebrhep Aa tet iene. 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