April 12, 1877] 



NA TURE 



52. 



but in the stratified liquid marked differences appeared between 

 the layers on readings being taken every five minute?. Thus in 

 ten minutes the readings were 31° (below), 18 "5° (middle), 18° 

 (top) ; after twenty minutes, 44°, I9*5°, 18° ; after fifty-five 

 minutes, 77°, 40°, 21°. The numbers prove, then, that in liquids 

 of decreasing density heat is distributed very slowly from below 

 upwards. Experiments in cooling led to a similar result. 



Prof. Quincke, of Heidelberg, has long experimented as 

 to whether gases can penetrate through the pores of glass. A 

 pressure of forty to one hundred and twenty atmospheres is 

 found to be incapable of forcing a perceptible quantity of 

 carbonic acid or hydrogen gas through a glass wall i '5 mm. 

 thickness, during a period of seventeen years. No loss of 

 weight was perceptible. M. Quincke, however, will not draw 

 the inference that the molecules of hydrogen and carbonic acid 

 have larger dimensions than the molecules or pores of the glass. 

 The distance at which the molecular forces of the glass act on 

 the gas-particles is of course greater thni the dimensions of the 

 molecules themselves. The pore walls of the glass may get 

 coated with an " absorbed " gas layer, which itself becomes im- 

 movable through the nearness of the solid substance, and hinders 

 the passage of gas particles from the interior of the glass tube 

 into the outer air. Perhaps, too, there may be dropable liquid 

 in the pores of the glass, preventing outflow of the gas. A 

 similar objection applies (according to M. Quincke) to M. 

 Traube's method ot determining the size of the molecules of a 

 substance from the possibility of passing through a so-called 

 " precipitate-membrane." 



A DROUGHT in excess of any that have occurred during the 

 last fourteen years, as regards long continuance and severity, has 

 prevailed for some months in Victoria and parts of Australia 

 adjoining. It terminated about February 12, and from that 

 date to the 22nd of the same month, when the mail left, heavy 

 thunderstorms and rainfall had prevailed, and cooler weather 

 set in. The reports from Deniliquin and other places in the 

 interior state that not a blade of grass was to be seen on the 

 plains, and cattle were dying in thousands. 



The Russian Naval Department proposes to send a ship this 

 summer to the mouths of the Obi and Jenissei to make a 

 thorough maritime survey of both gulfs. 



The Western Review of Science and Industry is the title of a 

 new monthly devoted to various departments of science, and 

 published in Kansas City, Mo. 



In view of the promising future of the African continent M. 

 Bernardin, of Ghent, has done a good service by publishing a 

 brochure (compiled from the works of various travellers), on the 

 commercial products of Central Africa. An excellent map of 

 Petermann's, showing the standpoint reached by exploration up 

 to September, 1876, is included in the pamphlet. 



The death is announced of Prof. P. Panceri, the eminent 

 Italian anatomist. He died suddenly whilst lecturing in the 

 University at Naples. 



The additions to' the Zoological Society's Gardens during the 

 past week include a Common Wolf {Cants lupus) European, 

 presented by Mr. J. A. Parlet ; a Ceylon Fish Owl {Ketupa 

 ceyloneusis) from Ceylon, presented by Capt. B. B. Turner; a 

 Vulpine Phalanger [Pkalangista vulpind) from Australia, pre- 

 sented by Mr. \V. Bazeley ; two' Sykes's Hemipodes ( Turnix 

 syhesii), a Rain Quail {Coturnix coromandelica), an Asiatic Quail 

 {Perdicula asiatica) from India, three Chinese Quails {Coturmx 

 chinensis) from China, presented by Mrs. Wood Mason ; an 

 Entellus Monkey {Semnopit/iecus entellus) from India, received 

 in exchange; a Collared Fruit Bat {Cynonycteris collaris) born 

 in the Gardens. 



SOCIETIES AND ACADEMIES 

 London 

 Chemical Society, April 5. — Prof. Odling, F.R.S., in the 

 chair. — A lecture on the discrimination of crystals by their 

 optical characters was delivered by Prof. N. S. Maskelyne, 

 F.R.S. After a few general remarks on the use, to the chemist, 

 of the methods employed by crystallographers, the lecturer pro- 

 ceeded to consider the methods of determining the symmetry of 

 crystals by their optical characters. The origin and meaning of 

 various terms used in crystallography were explained and illus- 

 trated by models, &c. ; the lecturer then threw on the screen, by 

 means of a polarising apparatus and the electric light, the 

 beautiful coloured effects produced by crystals of cerussite, 

 barytes, borax, &c., the effect of heat in altering the position of 

 the optical axes of a crystal of gypsum being especially beautiful. 

 In conclusion, the lecturer pointed out the ready means, which 

 the examination of the optical characters of a crystal under the 

 polarising microscope often afforded to the chemist, of acquiring 

 a great deal of information in a very short time, and expres^sed a 

 belief, that if chemists would work up suitable groups of crystals 

 for examination by the crystallographer, very important know- 

 ledge as to the functions of various groups of molecules in a 

 crystal would be gained. 



Anthropological Institute, March 27. — Col. A. Lane Fox, 

 F.R.S., V.P., in the chair.— Capt. W. Samuells, of the Bengal 

 Staff Corps, was elected a member. — An account of some 

 Kitchen Middens near Ventnor, by Mr. Hodder M. Westropp 

 was read by the director. A corn-crusher, of Scandinavian 

 appearance, was found in one of them, and in another higher up 

 in the cliff, there was discovered a small cinerary urn of un- 

 usual shape encircled with a pattern of coralline sea-weed. — 

 Messrs. W. Power and E. Laws communicated a short paper on 

 a Kitchen Midden near Tenby ; Dr. Crockley Clapham a paper 

 on the brain-weights of the Chinese and Pelew Islanders ; and 

 Mr. James Shaw some notes on right-handedness and improved 

 instinct in animals during the human period. Dr. Clapham 

 found that the weight of the brain both of the Chinese and the 

 Islanders was above the average, but they presented certain 

 peculiarities in their convolutions, The skulls of the Pelew 

 Islanders were markedly dolichocephalic. The size of the brain 

 of the Chinese and the Islanders was in no wise an index of the 

 intelligence possessed by them. 



Manchester 

 Literary and Philosophical Society, February 6.— E. W. 

 Binney, F.R.S., president, in the chair. — Notice of the Junior 

 Literary and Philosophical Society of Manchester, 1806-1807, by 

 W. E. A. Axon, M.R.S.L. — On compound combinations, by 

 Prof. Cayley, F.R.S., &c. — On ternary differential equation*, by 

 Robert Rawson. — On the powerful oxidising action of animal 

 charcoal upon organic matters as shown by the analysis of the 

 drainage from a large heap of a mixture of night-soil and animal 

 charcoal, by William Thomson, F.R.S. Edin. — A plea for the 

 word "Anglo-Saxon," by Rooke Pennington, LL.B., F.G.S. 



Cambridge 

 Philosophical Society, March 12. —Prof. Cayley, vice- 

 president, in the chair. — Prof. Clerk Maxwell communicated to 

 the Society a paradox in the theory of attraction. 

 P Q 



A 



B 



Let the line AB be divided in any given point C, and let 



PC-^ - AC-^ = eg-' - CB-' 

 be the condition of correspondence of two points P and Q, in 

 the segments A C, CB respectively, then if P and Q vary simul- 

 taneously, still remaining correspondent, 



PC—'d{PC) - CQ-'d(CQ), 

 or the corresponding elements are to each other as the squares of 

 their distances from C. If we now suppose that AB is a material 

 line of uniform density, the law of attraction being the inverse 

 square of the distance, the attractions of corresponding elements 

 on the point C will be equal and opposite. But every element 

 of .^C has a corresponding element in CB, and hence we might 

 conclude that the attraction of ^C on C is equal and opposite to 

 that of CB on C, which is evidently not the case, unless 

 AC= CB. The paradox is explained by considering that all 

 that we have proved is that the attraction of APon Cis equal 

 and opposite to that of QB on C, and this however near to C the 



