January 28, 1892] 



NA TURE 



II 



prepare all the members in the following series, and, with th : 

 exception of Nos. 4 and 10, all of them have been isolated 

 (I) CSI3, (,2) CsBrlg, (3) CsBrJ, (4) CsClIj, (5) CsClBrI, (6) 

 CsCIjI, (7) CsBrg, (8) CsClBrj; (9) CsCUBr, (10) CsClj. The 

 characteristics of these compounds have been fully studied. — 

 The law of elastic lengthening, by J. O. Thompson. The 

 author has made an extended and thorough investigation on 

 Hooke's law. The experiments were carried out at the Physical 

 Institute of the University of Strassburg, with the advice and 

 help of Prof. Kohlrausch. They lead to the following con- 

 clusions : — (i) The generally accepted law of elastic lengthening, 

 X ■= aP, according to which the lengthening x is proportional to 

 the stretching weight P is only an approximation. (2) The 

 relation between elastic extension and stretching weight can be 

 expressed by an equation of the following form : — 



X = oP+ /8P'' + T-ps, 



(3) The modulus of elasticity of the undeformed body can be 

 calculated with the help of the equation 



(»L-- 



(4) The true moduli of elasticity, calculated in this way, may be 

 as much as 16 per cent, larger than those determined in the 

 ordinary way. Consequently it will be necessary to recalculate 

 physical constants which depend on the modulus of elasticity. — 

 A method for the quantitative separation of strontium from 

 calcium by the action of amyl alcohol on the nitrates, by P. E. 

 Browning. — The relation of melting-point to pressure in case of 

 igneous rock fusion, by C. Barus. From the experiments on 

 diabase the relation of melting-point to pressure at 1200° is 

 dUldp — 021 ; at 1100°, d^ldp ='029. And since the probable 

 silicate value of dTjdp = "25 at 1170°, and as this falls within 

 the margin (020 to 030) of corresponding data for organic sub- 

 stances such as spermaceti, paraffin, &c., it is inferred that the 

 relation of melting-point to pressure, in case of the normal type 

 of fusion, is nearly constant, irrespective of the substance 

 operated upon. — The discovery of Clymenia in the fauna of the 

 Intume-cens zone (Naples beds) of Western New York, and its 

 geological significance, by John M. Clarke. — A new meteoric 

 iron from Garrett Co., Maryland, by A. E. Foote. A plate 

 accompanies this paper. — Farrington, Washington Co., Kansas, 

 aerolite, by G. F. Kunz and E. Weinschenk, — The skull of 

 Torosaurus, by O. C. Marsh. 



SOCIETIES AND ACADEMIES. 

 London. 



Royal Society, January 2i. — "Additional Observations on 

 the Development of Apleryx." By T. Jeffery Parker, B.Sc, 

 F.R.S. 



The paper is founded upon the study of three embryos of 

 Apteryx aiistralis obtained since the author's former communi- 

 cation on this subject was written. 



The youngest (stage E') is intermediate between E and F of 

 the former paper, the next (F') between F and G, the most 

 advanced (G') between G and II. 



In E' the characteristic form of the beak has already 

 appeared. 



in F' the pollex is unusually large, giving the fore-limb the 

 normal characteristics of an embryo wing. 



Several important additions and corrections are made to the 

 former ace >unt of the skull, especially with regard to the pre- 

 sphenoid region, the basi-cranial fontanelles, and the relations 

 between the trabecular and para-chordal regions. 



The account of the shoulder-girdle is amended. In Apteryx 

 oweni the coracoid region is solid, and no pro-coracoid appears 

 ever to be formed : in A. australis a ligamentous pro-coracoid 

 is present at a comparatively early period (stage F', and perhaps 

 E'). 



An intermedium is present in the carpus in all three specimens, 

 in addition to the elements previously described. 



The brain in stage G' is interesting, as being at what may be 

 called the critical stage ; the cerebellum is fully developed, and 

 the optic lobes have attained the maximum proportional size 

 and are lateral in position. In all essential respects the brain 

 of this emr.ryo is typically avian. 



Royal Microscopical Society, January 20.— Dr. R. 

 Brailhwaite, President, in the chair.— the Society adjourned 

 after passing a vote of sympathy and condolence to His Royal 

 Highness the Prince of Wales (Patron of the Society) on the 

 sad loss he had sustained.— This being the annual meeting, the 

 President's address, which was to have been read, was therefore 

 postponed till the next meeting, February 17. 



Edinburgh. 

 Royal Society, January 4.— Prof. Sir W. Turner, Vice- 

 President, in the chair. — Dr. Noel Paton read a paper on the 

 action of the auriculo-ventricular valves. It has hitherto been 

 supposed that, when these valves close, the two flaps are floated 

 up by the fluid, and, partially overlapping, prevent the passage 

 of the fluid by being pressed against each other. Thus it has 

 been supposed that, when closed, the upper surface of one flap 

 presses against the under surface of the other. Dr. Paton 

 has found, by direct experiment, that the flaps remain, on the 

 whole, in a pendant position, the upper surfaces of the two 

 being pressed together. — Mr. John Aitken read the second part 

 of a paper on the number of dust particles in the atmosphere of 

 certain places in Great Britain and on the Continent, with remarks 

 on the relation between the amount of dust and meteorological 

 phenomena. — Dr. Thomas Muir read a paper on a theorem re- 

 garding a series of convergents to the roots of a number. 

 The investigation was suggested by some work of the late Dr. 

 Sang. The series does not converge rapidly, and so cannot 

 be of great practical use.— Mr. Malcolm Laurie read a paper 

 on the development of the lung-books of Scorpio, and the 

 relation of the lung-»books to the gills of aquatic forms. He 

 was led to investigate this subject by observations made on the 

 allied fossil forms described in his paper read at the previous 

 meeting of the Society. He concludes that the lung-books are 

 not formed by a process of invagination, as is usually supposed 

 to be the case. He considers that the cavities are formed by 

 the growth of a protecting plate which finally adheres to the body. 



Sydney. 



Royal Society of New South Wales, November 4, 

 1891.— H. C. Russell, F.R.S., President, in the chair.— The 

 following papers were read : — Notes on Artesian water in New 

 South Wales, by Prof. David. — On the constitution of the sugar 

 series, by W. M. Hamlet. 



December 2.— H. C. Russell, F.R.S., President, in the 

 chair. — The following papers were read : — On kaolinite from 

 the Hawkesbury sandstone, by H. G. Smith. — Notes on some 

 New South Wales minerals (Note No. 6), by Prof. Liversidge, 

 F.R.S. — Notes on the rate of growth of some Australian trees, 

 by H. C. Russell, F.R.S. —Some folk-songs and myths from 

 Samoa, translated by the Rev. G. Pratt, with introductions and 

 notes, by Dr. John Fraser. 



Paris. 



Academy of Sciences, January 18. — M. Duchartre in the 

 chair. — Obituary notice on the late Sir George Biddell Airy, by 

 M. Faye. — On the mass of the atmosphere, by M. Mascart. It 

 is shown that the determination of the mass of the atmosphere 

 by observations of the pressures at the surface is open to serious 

 objections, and involves a notable error. The mass, calculated 

 by means of the formulae developed by M. Mascart, is one- 

 sixth greater than that usually obtained. The quantity of air 

 situated at a height of 64 kilometres is 1/700 of the total mass. 

 Particles of ice and water are suspended at this height, although 

 the air is so rarefied. It is therefore presumed that the density 

 does not diminish uniformly with increase of height above sea- 

 level, but decreases more slowly in high than in low strata. [On 

 this point see a note in Nature, p. 259.]— New note on the 

 resistance and small deformations of helical springs, by M. H. 

 Resal.— On solar statistics for 1891, by M. Rodolf Wolf. (See 

 Our Astronomical Column.) — Observations of Wolf's periodic 

 comet, made in 1891 with the great equatorial of Bordeaux Ob- 

 servatory, by MM. G. Rayet.L. Picart, and Courty. Observations 

 of position are given, extending from June 27 to December 27. — 

 On integrals of differential equations of the first order, possessing a 

 limited number of values, by M. P. Painleve. — On an arithmetical 

 theorem of M. Poincare's, by M. Victor Stanievitch. — On 

 organic compounds as solvents for salts, by M. A. Etard. — 

 Action of carbon monoxide on iron and manganese, by M. 



NO. I 161, VOL. 45] 



