384 



NATURE 



{Feb. 1 6, 



condensed upon it. — Mr. Peddle also read a note showing 

 that the phenomenon of "electric-absorption" must be 

 exhibited if a dielectric has a film of gas condensed on 

 its surface. — Prof. Tait communicated a paper by Mr. Albert 

 Campbell on the change in the thermo-electric properties 

 of tin at its melting-point. While the tin is solid its line on 

 the thermo-electric diagram is inclined upwards. Liquefaction 

 occurs before the line reaches that of iron. At this point the 

 direction of the line changes and becomes nearly identical with 

 that of iron. Thus the "specific heat of electricity" in tin 

 changes sign at the melting-point. This shows that the loosening 

 of molecular attraction, which occurs at the melting-point, pro- 

 duces the same effect in tin as is produced in iron, while still 

 solid, at the higher of the two temperatures at which its magnetic 

 and other properties suddenly alter, — Prof Tait read a paper on 

 the thermo-electric properties of Signor Battelli's iron ; and 

 showed from Mr. Omond's Ben Nevis observations that ice- 

 crystals may, in the greater number of cases, have at least a 

 share in the production of the observed phenomena. 



Paris. 



Academy of Sciences, February 6.— M. Janssen in the 

 chair. — Second note on the law of probabilities as applied to 

 target-firing, by M. J. Bertrand. The paper deals specially with 

 the objections urged by General Putz in the Revue d'Artilleric 

 against the principle admitted by Poisson, and against the law of 

 probability now generally adopted in schools of gunnery. 

 Reference was also made by General Menabrea to the important 

 researches of M. Siacci in this field of inquiry. — Remarks in 

 reply to an objection raised by M. Khandrikoff to the theory of 

 solar spots and protuberances, by M. H. Faye. During his 

 observation of the recent lunar eclipse Prof. Khandrikoff noted 

 some protuberances, the presence of which in the absence of 

 spots for some days before the eclipse seemed to militate against 

 M. Faye's well-known theory. To this objection M. Faye replied 

 at some length, pointing out that it is partly based on a misunder- 

 standing of the true character and bearing of his views. — On 

 perfect numbers, by Prof Sylvester. Recently M. Servais 

 stated that a perfect number (if such exist) containing only three 

 distinct prime factors is necessarily divisible by 3 and 5. It 

 is here shown that no such number exists, the line of argument 

 employed at the same time demonstrating the theorem that there 

 exists no perfect number containing less than six distinct prime 

 factors. — Observations made at the Observatory of Algiers 

 during the total lunar eclipse of January 28, by M. Ch. Trepied. 

 These observations comprise, among other matters, a study of 

 the colours assumed by the lunar disk ; a spectroscopic examina- 

 tion of the eclipsed portion of the disk ; and the occuitations of 

 the stars contained in the list prepared by the Observatory of 

 Pulkowa for the purpose of obtaining an exact determination of 

 the apparent diameter of the moon. Communications were also 

 received from the Observatories of Bordeaux and Nice on various 

 phases of the same occurrence. — Ephemeris of the planet 252 for 

 the opposition of the year 1888, by M. Charlois. The true 

 positions, right ascension and declination, are given for the 

 period from March 5 to March 19. At opposition (March 12) 

 the magnitude will be I3'4. — Note on permanent deformations 

 and thermodynamics, by M. Marcel Brillouin. Two propositions 

 are established : (i) that for most elastics solids there exists no 

 finite relation between the temperature t, the mechanic variable 

 X, and the geometric variable x ; (2) that for most solid bodies 

 there exists a linear equation with total differentials between t, 

 X, and j; : or, more correctly, there exist as many equations of 

 this class as there are independent geometric variables. In a 

 future communication the theoretic results of this study will be 

 announced. — Influence of diet in determining the fixation and 

 elimination of carbon in man, by MM. Hanriot and Ch. Richet. 

 The results are tabulated of mixed nitrogenous, fat, and feculent 

 diets, including beef, bread, potatoes, butter, cheese, sugar, wine, 

 and coffee, continued for a period of fifteen days, — On the 

 presence of striated muscles in mollusks, by M. Raphael 

 Blanchard. M. Hermann Fol's recent statement that true 

 transversal striation of the muscular fibre is found in no mollusk, 

 is shown to be erroneous and based on defective observation of 

 these organisms, in some of which true transversal striation cer- 

 tainly occurs. — On the endomorphic modifications of the granu- 

 litic systems in Morbihan, Brittany, by M. Charles Barrois. This 

 paper is devoted to a careful study of the remarkable endo- 

 morphic modifications and mechanical transformations of the 

 Guemene, Saint -Jean Brevelay, and Grandchamp granulitic 



formations, which traverse the Department of Morbihan in its 

 entire length, and the typical constituents of which are : 

 (i) zircon, apatite, black mica, oligoclase, orthose, and quartz ; 

 (2) orthose, microcline, quartz, tourmaline, and white mica. — On 

 the Senonian and Danian systems of South-East Spain, by M. 

 Rene Nickles. Without attempting accurately to determine the 

 respective limits of these formations, the author indicates the 

 presence of extensive marine deposits in the Devonian contain- 

 ing fossiliferous limestones with several species of Hemipneustes 

 associated with large banks of Hippurites and Pironea. — General 

 Menabrea presented to the Academy the prospectus of a new 

 edition of the works of Galileo, in about twenty-five volumes, 

 which is about to be issued at the expense of the Italian Govern- 

 ment, and copies presented to all the more important public libra- 

 ries, — The Administrative Commission of the Academy announces 

 that it has decided to supply Corresponding Members with the 

 Coniptes rendtis free of charge from January i, 1888. Cor- 

 respondents are requested to acknowledge receipt of the first 

 number, and notify their change of address to Messrs. Gauthier- 

 Villars et Fils, publishers, Paris. 



BOOKS, PAMPHLETS, and SERIALS RECEIVED. 



A Treatise on Photography, 5th edition : Capt. Abney (Longmans). — The 

 Story of Creation : E. CloUd (Longmans). — British Dogs, parts 15 and 16 : H. 

 Dalziel (U. Gill). — Beobachtungen der Rtissischen Polarstation an der Lena- 

 miindung, ii. Thiel, Meteorologische Beobachtungen: A. Eigner ; H. Liefg. 

 Beobachtungen vom Jahre 1883-84 : R. Len2. — Meteorological Observations 

 at Stations of the Second Order for the Year 1883 (Eyre and Spottiswoode). 

 — The Geographical Distribution of the Family Charadnidae, H. Seebohm 

 (Sotheran). — Annuario publicado pelo Imperial Observatorio do Rio de 

 Janeiro, 1885-86-87 (Rio de Janeiro). — Memoirs and Proceedings of the 

 Manchester Literary and Philosophical Society, 4lh Series, vol. i. No. 2. — 

 (Manchester). — Proceedings of the Manchester Literary and Philosophical 

 Society, vol. xxvi. (Manchester). — Zeitschrift der Gesellschaft fiir Erdkuml 

 zu Berlin, Nos. 133 und 134 (Reimer, Berlin). 



CONTENTS. PAGE 



Kinematics and Dynamics. By Prof. A. G. Green- 

 hill ." 361 



Atlas of the Distribution of Plants 362 



Our Book Shelf:— 



McCook : " Tenants of an Old Farm " 363 



Daly : " Digging, Squatting, and Pioneering Life in 

 the Northern Territory of South Australia "... 363 



' ' Photography Simplified " 363 



Letters to the Editor : — 



An Explanation explained. — Prof. John W. Judd, 



F.R.S 363 



Reason and Language. — Dr. St. George Mivart, 



F.R.S 364 



Mechanical Equivalent of Heat. — Prof. Alfred 



Lodge 365 



" Is Hail so formed ? " — Cecil Carus- Wilson . . . 365 

 The New Army Regulations. — Henry Palin Gurney 365 

 "British and Irish Salmonidae." — Dr. Francis Day ; 



Your Reviewer 366 



Modern Views of Electricity. Part III. — Magnetism. 

 VIII. {Illustraied.) By Dr. Oliver J. Lodge, 



F.R.S 366 



The Mechanism of the Flight of Birds. {Illustrated.) 



By Prof. E. H. J. Marey 369 



Technical Education 374 



Threatened Scarcity of Water. By Charles Harding 375 



Professor Asa Gray 375 



Notes 377 



Our Astronomical Column : — 



Melbourne Observatory 381 



The American Nautical Almanac Office 381 



Astronomical Phenomena for the Week 1888 



February 19-25 381 



Geographical Notes 381 



Our Electrical Column 382 



Making Glass Specula by Hand. By A. Ainslie 



Common, F.R.S 382 



Societies and Academies 3^3 



Books, Pamphlets, and Serials Received 384 



