heoretically the sum of the reflecting, absorbing and transitting powers should be unity, but from the above table it will : noticed that they exceed 100 per cent., by amounts greater an can be accounted for by experimental error. This disepancy, the author thought, might be attributed to the law of sines not being exactly fulfilled. Mr. A. P. Trotter said he d been interested in the subject of diffusion for many years th a view to obviating the glare of arc lamps. Some experients he made on reflecting power gave unsatisfactory results, ing, as he now saw, to his not taking the solid angles subided by the reflecting surfaces into account. The reflecting wer of substances was of great importance in the illumination rooms; in one case measured by Dr. Sumpner and himself, o-thirds of the total illumination was due to the walls. It uld greatly simplify measurement of reflecting power if some Ostance could be adopted as a standard. Referring to the ane law, he said he had found it true, except when the angles incidence approached 90°. In cases where considerable total lection took place the apparent brightness near the normal ection was greatly in excess of that in other directions. ese points he illustrated by polar curves. He had also conered what should be the nature of a roughened or grooved face to give the cosine law of diffusion. No simple ge»rical form of corrugations, &c., seemed to fulfil the required ditions. Dr. Hoffert said the high numbers given for the ecting powers of substances were very interesting. Most ple had noticed the effect of laying a white table cloth in an He had also observed that wall papers of the inary room. same pattern, but slightly different in colour, had very different effects in producing increased illumination, and wished to know if the influence of small differences in colour and texture on diffusing power, had been investigated. Mr. Blakesley defended the cosine law, and suggested that the summation of the powers exceeding unity might be due to the fact that the enclosure reflected heat as well as light, thus raising the temperature and increasing the efficiency of the radiant. Mr. Addenbrooke said the importance of the subject was impressed on him when he passed through America three years ago and noticed the crude manner in which electric lighting was there carried out. If using good reflecting surfaces increased the illumination of a room 50 per cent., it was like reducing the cost of electricity from 8d. to 4d. per unit. He could hardly conceive any subject of more practical importance than the one before the meeting. Dr. C. V. Burton did not understand why the cosine law should be objected to, for it was possible that no surface was perfectly diffusive. The effect of reflection from walls, &c., say in illuminating a book would not, he thought, be so great as would appear from the numbers given, for one usually read near a light, and the reflected light falling on the book was only a small part of the whole, on account of the greater distances of the walls. Another member pointed out that in experiments such as those described, it was very important to screen the photometer and surfaces from all radiation other than that under test. He rather doubted whether any surface reflected as well as mirrors. White surfaces might ap ear to do so, but this was probably because the eye would overestimate it, owing to the superiority of white in aiding distinct vision. Dr. Sumpner in reply said he had, as stated in the paper, used white blotting paper as a standard of reflecting power and found it very convenient. His most careful measurements had been made on whitish surfaces and not on coloured ones. Where one colour, say red, preponderates in a room, the average light would be much redder than that emitted by the source owing to the other colours being absorbed. In considering illumination as related to distinct vision, it was necessary to take account of the eye itself, for the pupil contracted in strong lights and opened in feeble ones. This subject he hoped to treat fully in a subsequent paper. Entomological Society, December 7.-Frederick DuCane Godman, F.R.S., President, in the chair. -The President announced the death, on December 2, of Mr. Henry T. Stainton, F. R.S., an ex-President and ex-Secretary of the Society. Mr. Jenner Weir exhibited a spec es of Acræa from Sierra Leone, which Mr. Roland Trimen, F. R.S., who had examined the specimen, considered to be a remarkable variety of Telchinia encedon, Linn. It was a very close mi ic of Limnas alcippus, the usual West African form of Limnas chrysippus. The upper wings of the specimen were rufous and the lower white, as in the model, and the resemblance in other respects was heightened by the almost total suppression of the black spots in the di-c of the upper wings, characteristic of the usual markings of T. encedon.- Mr. F. J. Hanbury exhibited a remarkable variety of Lycana adonis, caught in Kent this year, with only one large spot on the under side of each upper wing, and the spots on the lower wings entirely replaced by suffused white patches. He also exhibited two specimens of Noctua xanthographa of a remarkably pale brownish grey colour, ap: proaching a dirty white, obtained in Essex, in 1891; and a variety of Acronycta rumicis, also taken in Essex, with a dark hind margin to the fore wings.-Mr. H. J. Elwes exhibited a living specimen of a species of Conocephalus, a genus of Locustide, several species of which, Mr. McLachlan stated, had been found alive in hothouses in this country -Dr. T. A. Chapman exhibited immature specimens of Taniocampa gracilis, T. gothica, T. populeti, T. munda, T. instabilis and T. leucographa, which had been taken out of their cocoons in the autumn, with the object of showing the then state of development of the imagos. Mr. F. W. Frohawk exhibited a living specimen of the larva of Carterocephalus palæm»n (Hesperia paniscus) hybernating on a species of grass which he believed to be Bromus asper. The Rev. Canon Fowler and Mr. H. Goss expressed their interest at seeing the larva of this local species, the imagos of which they had respectively collected in certain woods in Lincolnshire and Northamptonshire. Mr. Goss stated that the tood-plants of the species were supposed to be Plantago major and Cynosurus cristatus, but that the larva might possibly teed on Bromus asper.—Mr. C. G. Barrett exhibited a long series of remarkable melanic varieties of Boarmia repandata, bred by Mr. A. E. Hall from larvæ collected near Sheffield.—Mr. W. Farren exhibited four varieties of Papilio machaon from Wicken Fen; also a series of two or three species of Nepticula pinned on pith with the "minutien Nadeln," for the purpose of showing these pins.-Canon Fowler exhibited specimens of Xyleborus perforans, Woll.. which had been devastating the sugar-canes in the West Indies.-Mr. E. B. Poulton, F.R. S., showed, by means of the oxy-hydrogen lantern, slides of various larvæ and pupæ, in illustration of his paper, read at the October meeting, entitled, "Further experiments upon the colourrelation between certain lepidopterous larvæ and their surroundings." He stated that he believed that nineteen out of twenty larvæ of Geometrida possessed the power of colour adjustment. Mr. F. Merrifield, the Rev. J. Seymour St. John, and Mr. Jacoby took part in the discussion which ensued. -Mr. F. Merrifield read a paper entitled, "The effects of temperature on the colouring of Pieris napi, Vanessa atalanta, Chrysophanus phlaas and Ephyra punctata," and exhibited many specimens thus affected. Mr. Poulton, Dr. F. A. Dixey, Mr. Elwes, and Mr. Jenner-Weir took part in the discussion which ensued. Mr. Kenneth J. Morton communicated a paper entitled, "Notes on Hydroptilida belonging to the European Fauna, with descriptions of new species."-Dr. T. A. Chapman read a paper entitled, "On some neglected points in the structure of the pupa of Heterocerous Lepidoptera, and their probable value in classification; with some associated observations on larval prolegs." Mr. Poulton, Mr. Tutt, Mr. Hampson, and Mr. Gahan took part in the discussion which ensued. Mr. J. Cosmo-Melvill communicated a paper entitled, Description of a new species of butterfly of the genus Calinaga, from Siam."-Mr. W. L. Distant communicated a paper entitled, Descriptions of new genera and species of Neotropical Rhynchota.' 66 66 PARIS. Academy of Sciences, December 12.-M. d'Abbadie in the chair. On certain asymptotic solutions of differential equations, by M. Emile Picard.-Description of a new electric furnace, by M. Henri Moissan. The furnace consists of two bricks of quicklime one upon the other, the lower one of which is provided with a longitudinal groove which carries the two electrodes, and between them is a small cavity serving as crucible, which contains a layer of several centimetres of the substance to be experimented upon. The latter may also be contained in a small carbon crucible. The highest temperature worked with was 3000° C., produced by a current of 450 amperes and 70 volts consuming 50 horse-power. In the neighbourhood of 2500°, lime, strontia and magnesia crystallized in a few minutes. At 3000° the quicklime composing the furnace began to run like water. At the same temperature the carbon rapidly reduced the oxide of calcium to the metallic state. The oxides of nickel, cobalt, manganese, and chromium were reduced in a few seconds at 2500°, and a button of uranium weighing 120 gr. was obtained from the oxide in ten minutes at 3000°.-Action of a high temperature on metallic oxides, by M. Henri Moissan. In all the experiments, the simple elevation of temperature produced the crystallization of all the metallic oxides experimented upon.-On the existence of the diamond in meteoric iron of the Cañon Diablo, by M. C. Friedel. A careful analysis has placed beyond doubt the existence of diamond in a portion of the Arizona meteorite presented to the Ecole des Mines. It occurs in small grains or a fine powder disseminated through the iron. — On the laws of expansion of fluids at constant volume; coefficients of pressure, by E. H. Amagat.-On the means of diminishing the pathogenic power of fermented beet-root pulp, by M. Arloing. -On the employment of free balloons for meteorological observations at very great heights, by M. Ch. Kenard.-Photographic observations of Holmes's comet, by M. H. Deslandres.-On the locus of the mean distances of a point of an ordinary epicycloid, and of the successive centres of curvature which correspond to it, by M. G. Fouret.-On ordinary linear differential equations, by M. Jules Cels.-On the common cause of the evaporation and surface tension of liquids, by M. G. van der Mensbrugghe. -On the relation between the velocity of light and the size of the molecules of refracting liquids, by M. P. Joubin. From a comparison of a large number of substances the following law is deduced: The refraction is proportional to the square root of the quotient of the weight of the molecule by the number of constituent atoms (mean weight of the atom).-On the anomalous propagation of the light waves of Newton's rings, by M. Ch. abry. On transparent diffusing globes, by M. Frédureau. On a relation between molecular heat and the dielectric constan by M. Runolfsson.-On the employment of guard-ring c densers and absolute electrometers, by M. P. Curie.-On ik density of oxide of carbon and the atomic weight of carbs, M. A. Leduc.-Critical reduction of Stas's fundamental ce minations on potassium chlorate, by M. G. Hinrichs.-0 chloro-iodide of carbon, by M. A. Besson.-Action of an drous hydrofluoric acid on the alcohols, by M. Maurice Mesha -Action of sulphuric acid on citrene, by MM. G. Bouchard and J. Lafont.-Analysis of sulphate of quinine and quantita determination of quinine in presence of the other cinch | alkaloids, by M. L. Barthe.--On the assimilation of the omac to the abomasum of the Ruminants from the point of view the formation of their mucous membrane, by M. J. A. Corder -On the differential osteological characters of rabbits and have comparison with leporides, by M. F. X. Lesbre.-Remarks the preceding communication, by M. Milne-Edwards. -My sporidia of the bile-duct of fishes; new species, by M. Thélohan. Method for ensuring the conservation of vitali plants brought from distant tropical regions, by M. Max Cornu. On the difference of transmissibility of pressures ligneous, herbaceous, and suculent plants, by M. Ga Bonnier. On the structure of the Gleicheniacea, by M. Geom Poirault.-Salivary secretion and electric excitation, by MA Wedensky. -Action of the extract of cows' blood on anim affected with glanders, by M. A. Babes.-The blizzard December 6 and 7, 1892, by M. Ch. V. Zenger. BOOKS and SERIALS RECEIVED. Books-The Elements of Graphic Statics: L. M. Hoskins (Mam!-Qualitative Analysis Tables and the Reactions of certain rganic stances: Dr. E. A. Letts (Belfast, Mayne and Byd).-L rd Rosse Gospel Modernized by E. L. Garbett (W. Reeves) -An Atlas of As nomy Sir R. S. Ball (Philip). -Pioneers of Science: Prof. O. Lodge X millan).-Collected Mathematical Papers of Prof. A. Cayley: (Camb. Univ. Press).- British Journal Photographic Almanac (Greenwood).-A Manual of Bacteriology: Dr. G. M. Sternbera X York, Wood).- La Terre Les Mers et Les Continents: F. Prien J. B. Baillière). SERIALS-L'Anthropologie, Ton. 3. No. 5 (Paris, Masson) —Eont Journal, December (Macmillan and Co ).—Journal of the Chemical ser December (Gurney and Jackson). CONTENTS. Mr. C. Dixon on Bird-Migration Vasey: "Grasses of the Pacific Slope, including Letters to the Editor: Macculloch's Geological Map of Scotland.-Prof. J Glaciers of Val d'Herens.-William Sherwood The Earth's Age.-Bernard Hobson; Dr. Alfred P GLASS-TOPPED BOXES, CARD TRAYS, &c. HUGH FULTON (Conchologist), WIMSHURST MACHINES. With Glass Plates, all sizes, double and multiple LARGE CATALOGUE, Fifth Edition, Royal 8vo, KING, MENDHAM, & Co., Western Electrical Works, Bristol London Address: 12 FENCHURCH STREET, E.C. (W. B. ALLISON, AGENT.) ESTABLISHED 1876. NOTICE.-Advertisements and business letters for SIR ROGER DE COVERLEY. Reprinted from the Spectator. With Illustrations by HUGH THOMSON. New Edition. Crown 8vo, elegant, 65. Also with uncut edges, paper label, 6s. CRANFORD. By MRS. GASKELL. With Preface by ANNE THACKERAY RITCHIE, and 100 Illustrations by HUGH THOMSON. Crown 8vo, 6s. Also with uncut edges, paper label, 6s. THE VICAR OF WAKEFIELD. By OLIVER GOLDSMITH. A New Edition. With OLD CHRISTMAS. From the Sketch- SKETCHING RAMBLES IN HOL- COACHING DAYS and COACHING 21S. OLD CHRISTMAS AND BRACE- THE OREGON TRAIL. By FRANCIS MACMILLAN AND CO., LONDON. MESSRS. MACMILLAN & CO.'S NEW BOOKS. NEW VOLUME OF SERMONS BY THE LATE CATHEDRAL AND UNIVERSITY SER- BY THE HEAD MASTER OF HAILEYBURY. MOTHERS AND SONS; or, Problems MESSRS. MACMILLAN AND CO.'S NEW BOOKS. NEW BOOK BY PROF. OLIVER LODGE, PIONEERS OF SCIENCE. BY OLIVER LODGE, F.R.S., Professor of Physics in the Victoria University College, Liverpool. With Portraits and other Illustrations. This book takes its origin in a course of lectures arranged for me in the year 1887 by three of my leagues, one of whom gave the course its name. The lectures having been found interesting, it was natural to write them out in full and publish. If I may speak of their merit, I should say it consists in the simple statements and explanations of scientific ts and laws. The biographical details are compiled from all readily available sources; there is no novelty originality about them, though it is hoped there may be some vividness. I have simply tried to present a ing figure of the man, and to trace his influence on the progress of thought.-FROM THE PREFACE. NEW BOOK BY SIR JOHN LUBBOCK. HE BEAUTIES OF NATURE; and the Wonders of the World we Live in. COMPLETION OF PROF. MICHAEL FOSTER'S "PHYSIOLOGY." HE CHEMICAL BASIS OF THE ANIMAL BODY. An Appendix to Foster's "Text-book of Physiology." Fifth Edition. By A. SHERIDAN LEA, M. A., D.Sc., F.R.S., University Lecturer in Physiology in the University of Cambridge; Fellow of Caius College. The following appendix has been written upon the same lines as in former editions, save that it has been enlarged, and in reality v constitutes a treatise on the chemical substances occurring in the animal body. As in former editions it is entirely the work of A. Sheridan Lea. The references given, though extensive, are not intended to be exhaustive. An effort has been made to make references to recent works as complete as possible, other references are to papers, which them elves give full references, and will thereserve as a guide to literature of the subject; and some have been inserted in order to inform the student of the dates at which Sortant results were first described."-From the Preface. Now Ready, 2 Vols. 8vo, 30s. net. LECTRICAL PAPERS. By OLIVER Heaviside. NEW WORK BY MR. R. B. HAYWARD. HE ALGEBRA OF COPLANAR VECTORS AND TRIGONOMETRY. By R. BALDWIN HAYWARD, M. A., F. R. S., Senior Mathematical Master in Harrow School, formerly Fellow of St. John's College, Cambridge. Crown 8vo, Cloth. NEW BOOK ON MECHANISM. ODERN MECHANISM. Exhibiting the latest progress in Mechanics, Motors, and the Transmission of Power. Edited by PARK BENJAMIN, LL.B., Ph. D., Editor of " Appleton's Cyclo of Applied Mechanics" Edition of 1880, Me nber of the American Society of Mechanical Engineers, of the American Institute of Electrical Engineers, and of the British Chartered Institute of Patent Agents. Illustrated. THE FIRST VOLUME OF "NATURE'S STORY BOOKS." Now Ready, Crown 8vo, Cloth, 65. NSHINE. BY AMY JOHNSON, LL.A., formerly Head Mistress of the Royal Academy, Inverness. The first of a series of books intended to present some leading scientific principles in such a form as to arouse the interest of ren. As far as possible Miss Johnson has drawn her illustrations from common things, and has devised her experiments to suit mplest apparatus. SCHOOLMASTER:-"The writer of this book must indeed be a capital teacher, and her lessons should be studied by all who o acquire the art of teaching. The book dealing with the phenomena, usually included under the head of 'Light,' is quite a ouse of novel and interesting experiments, and is a 'boon and a blessing.' The experiments can nearly all be carried out by en, are fully described, do not involve the purchase of expensive material, and are in all cases made subservient to the author's se, which is to enable her youthful pupils to obtain sound knowledge by appealing to nature herself in as pleasant and as gh a way as possible. We can heartily congratulate her upon the success her efforts have met with, and can assure our s that they will certainly find her lessons bright as sunshine.' MACMILLAN AND CO., LONDON. |