448 



NA TURE 



[September i, 1904 



SOCIETIES AND ACADEMIES. 



Edinburgh. 

 Royal Society, July 4. — Prof. Geikie in the chair.— 

 Prof. Cunningham read an obituary notice of the late Prof. 

 His, honorary fellow.— Dr. J. Halm, in a note on the 

 structure of the series of line spectra, gave an interesting 

 extension of Balmer's formula for the distribution of lines 

 in a spectrum. Various other formula have been given by 

 Rydberg, Kayser and Runge, and others, but none are satis- 

 factory in the sense of being applicable to all substances. 

 Balmer's formuliE for the two hydrogen series may be put 

 in the forms i/n = airr, and i/n = a(m-4)-, where a is a 

 constant and n is the difference of the oscillation frequencies 

 of the last line of the series and of the mth line in the 

 spectrum. Dr. Halm finds that the series of any other 

 substance can be represented with great accuracy by either 

 of the formula; i/H = ain- + b, i/n = a{m-if + b, where b 

 is a constant characteristic of the particular substance. 

 The whole sets of series for all substances may be repre- 

 sented very concisely by a geometric figure consisting of 

 one set of radiants and a set of transversals each one of 

 which corresponds to the line spectrum of a substance. — 

 Mr. J. R. Milne described some of the modifications of his 

 new form of spectrophotometer for measuring the light 

 absorption of dilute solutions. The main feature considered 

 was the use of a WoUaston prism so as to act in the reverse 

 way, that is, to bring together two different rays, instead 

 of separating one ray into two. — The Rev. F. H. Jackson 

 communicated a paper giving the complete solution of the 

 differential equation satisfied by his generalised form of 

 Bessel function. 



July 18. — Sir John Murray in the chair. — Dr. T. H. 

 Bryce read a paper on the histology of the blood of the 

 larva of Lepidosiren (part ii., histogenesis). The paper 

 dealt with the development of the blood corpuscles, and 

 was fully illustrated with lime-light projections. One of 

 the most important results concerned the origin of the 

 leucocytes. They were found arising in situ, before the 

 appearance of thymus or spleen, in specialised tracts of the 

 mesenchyme, first in the splanchnic layer and slightly later 

 in the tissue round the nephric tubules. — Mr. J. R. Milnci 

 in some notes on experiments in spectrophotometry, gave 

 an account of his method for obtaining what might be called 

 an artificial line spectrum, and so enabling him to use a 

 powerful and steady source of light. In front of the photo- 

 graphic plate an opaque screen with a series of fine trans- 

 parent slits was set. Only the parts of the continuous 

 spectrum corresponding in position to these slits were photo- 

 graphed on the plate. When a solution of an absorbent 

 substance was introduced, the spectrum photographed was 

 shortened and a fewer number of lines were photographed ; 

 but by widening the slit and so increasing the intensity of 

 light it was possible to obtain the original length of spec- 

 trum. In this way, in terms of the intensities of light, an 

 estimate of the absorbing power of different solutions could 

 be obtained, probably quite as accurate as by any of the 

 other known methods. — In a note on the magnetic condition 

 of nickel demagnetised by decreasing reversals, Mr. J. 

 Russell discussed the production of magnetisation at right 

 angles to a magnetising force which is made to act upon 

 a toroidal tube of nickel after the metal has been de- 

 magnetised by reversals. The force was applied at various 

 orientations relatively to the direction of the original 

 magnetisation, which was apparently destroyed by the re- 

 versals. Results for iron have already been published, 

 and the results for nickel are similar, though differ- 

 ing considerably in detail. Thus in nickel the trans- 

 verse induction is much smaller than in iron, being roughly 

 speaking about a twentieth. Also the maximum, which in 

 the case of iron is obtained when the applied field makes 

 an angle of 45° with the original direction of magnetisation, 

 is obtained in the case of nickel at other orientations. — Prof. 

 Chrystal read a paper on some particular results in the 

 theory of seiches. The differential equation of free 

 oscillations of a lake of water was found to be capable of 

 a comparatively simple solution when the longitudinal 

 section of the lake was bounded below by a parabola, either 

 concave or convex upwards. The solution was obtained in 

 the form of series which were particular cases of hyper- 

 geometric series, but which do not seem to have been dis- 



cussed. They had properties which were analogous to the 

 properties of sines and cosines, and the functions were 

 accordingly named the seiche-sine, the seiche-cosine, and the 

 hyperbolic seiche-sine and seiche-cosine. In a particular 

 case of special interest in the seiche problem the roots of 

 the cosine and sine are the products 1-2, 34, 56, &c., and 

 -3, 4'5' ^7< ^■<^-' respectively, and this corresponds to the 

 case of the concave parabolic bottom. The roots for the 

 hyperbolic function are not so easily found. They correspond 

 to the case of the convex parabolic bottom, that is, a lake 

 with a shallow in the middle and deeper parts towards the 

 ends. Some promising applications of the investigations 

 have already been made, and it is hoped that when more 

 experimental data are accumulated in regard to the periods 

 of the uni-nodal, bi-nodal, tri-nodal, &c., oscillations, a real 

 explanation of the seiche phenomena will be obtained. 

 Paris. 

 Academy of Sciences, August 22. — M. Mascart in the chair. 

 — The flow of underground water : J. Boussinesq. A 

 continuation of preceding papers on the same subject. — On 

 stelliform or ramefied cartilage : Joannes Chatin. This 

 type of cartilage has been found in the larynx of a mammal. 

 — Thermoelectric inversion and the neutral point : G. 

 de Metz. Previous researches have indicated two simple 

 relations between the temperature of inversion and the 

 neutral point. The author has examined the behaviour of 

 several couples at temperatures down to —185° C, and has 

 found that these equations hold only for the platinum-zinc 

 couple. This couple is therefore valuable for the measure- 

 ment of low temperatures. — The study and synthetical 

 preparation of some symmetrical cyclic thio-ureas : Emm. 

 Pozzi-Escot. The primary amines react- with carbon 

 bisulphide in alcoholic solution in presence of caustic potash, 

 with evolution of sulphuretted hydrogen. Details are given 

 of the properties of several of these thio-ureas. — On the 

 freezing point of milk in health and disease : MM. Giraud 

 and Lasserre. Milk from healthy subjects has a freezing 

 point of — o°55 to — o°-56. In the case of diseased subjects 

 the freezing point is slightly lower, — o°.58 to — o°-6i. 



CONTENTS. PAGE 



American and British Yachting. By Sir W. H. 



White, K.C.B., F.R.S 421 



A Co-nprehensive Work on Physics 422 



Our Book Shelf:— 



Walden: "Wilhelm Oswald."— A. S 422 



Barrett : " The Lepidoptera of the British Islands. A 

 Descriptive Account of the Families, Genera, and 

 Species Indigenous to Great Britain and Ireland, 

 their Preparatory States, Habits, and Localities " . 423 

 Letters to the Editor : 



The Flowering of the Bamboo.— J. S. Gamble, F.R.S. 423 

 The Spontaneous Scintillations of Hexagonal Blende. — 



E. P. Perman . 424 



Sooty Rain. — Prof. J, B. Cohen . . 424 



Adaptive Colours of Eyes. — A. Vincent Napier . . 424 

 An Optical Phenomenon. — C. T. Whitmell , . . 424 

 The Constitution of Matter. — C.Alfred Smith . . 424 

 The Infants' Milk Depot. [lUiistraUd.]. By Prof. 



R. T. Hewlett .425 



Exhibition of Ancient Egyptian Sculpture at the 



British Museum 426 



The British Association at Cambridge 426 



Section E. — Geography. — Opening Address by 



Douglas \^. Freshfield, President of ihe Section 427 

 Section G. — Enpineering. — Opening; Address by Hon. 

 Charles A. Parsons, M.A., F.R.S., M.Inst. 

 C.E., President of the Section . .... 434 



Section H. — Anthropology. — Opening Address by 

 Henry Balfour, M.A., President of the Section . 438 



Notes 444 



Our Astronomical Column : — 



Astronomical Occurrences in September 447 



Catalogue of Stars near the South Pole . .... 447 

 Annual Report of the Paris Observatory (1903) 447 



Photographic Magnitudes and Places of 350 Pleiades 



Stars 447 



University and Educational Intelligence 447 



Societies and Academies 4(8 



NO. 1818, VOL. 70] 



