October 17, 1895J 



NATURE 



611 



HiiUetiii dd t Academic Koyale dc Relgigiie, No. 6. — The con- 

 (lilions under which hydrogen peroxide is decomposed, by W. 

 Spring. The cataly.sis of hydrogen peroxide takes place without 

 chemical action by contact with various substances when the 

 formation of water is favoured. Any substance which is more 

 easily impregnated with water than with HjO.j l)rings about the 

 decomposition of the latter. K solution of Jl.jO^ containing 

 salts is the seat of a decomposition whose activity increases with 

 the temperature. — Chemical study of eight earths of the Lower 

 Congo, by E. Stuyvaert. The analysis of earths from Boma, 

 Zenze, Banza-Kasi, Mayombe, and \ungu-Mumba proves that 

 the soils of the Lower Congo, sandy as well as calcareous, are 

 provided with reserves of phosphoric acid and potash which 

 insure a high fertility. It is certain that in the territories where 

 the disappearance of forests has not modified the rainfall, as in 

 Mayombe, the cultivation of coffee, cocoa, anfl other economic 

 ])lants can be carried on for a long time without the use of 

 manure. — On the critical temperatures of solution and their 

 application to general analysis, by L. Crismer. The critical 

 temperatures of solution may be used for the identification of 

 chemical bodies without the necessity of weighing them, and 

 they firm a valuable additional criterion for the purpose of 

 <_jualitative analysis. The critical temjierature of solution is 

 intlepeiident of the amount of either body present. It varies 

 very much fr<jm one substance to another, liut is constant for the 

 same substance. I'or a mixture of two bodies, it is sensibly 

 equal to the arithmetical mean of those of the constituents 

 liken singly. Just as the surface tension of a liquid is reduced 

 to zero at the critical temperature of vaporisation, so the surface 

 tension of the lower liquid tends towards zero at the critical 

 temperature of solution, and the meniscus separating them 

 becomes a plane. .\n optical method of determining these 

 critical temperatures may be based upon this fact. 



Wicdentaiiii i: Annalen dcr fhy.iik tiiid Chcmii.\ Xo. 9. — 

 Double refraction of electromagnetic rays, by Peter Lebedew. 

 The author succeeded, by a modification of Hertz's apparatus, in 

 dealing with waves not ntore than 0'6 cm. long, and in demon- 

 strating the phenomena of polarisation, reflection, and refraction 

 with apparatus of the size ordinarily used in optics. The 

 resonator used was a small ihermo couple of iron and " constan* 

 tane.'' An ebonite prism i 'S cm. long showed refraction to 

 within 3° of arc. Rhombic sulphur showed measurable double 

 refraction, and a " N'icoll prism" was successfully constructed 

 <jf two sidphur prisms w ith a plate of ebonite in place ot the 

 Canada balsam. — Luminescence of organic substances in the 

 three states, by K. Wiedemann and (i. C. Schmidt. Many 

 <irganic vapours show true fluorescence, and some, like naphtha- 

 lene, give composition spectra under the electric discharge, with- 

 out being dissociated. Kathode luminescence is shown by many 

 organic liquids, and the colour correspontls to that of the vapour. 

 But the luminescence of the solid bodies often differs from that 

 in the li(|uid state. Solid anthracene shows green, gaseous 

 anthracene blue luminescence. — A vibration galvanometer, by 

 II. Rubens. This instrument somewhat resembles Wien's optical 

 telephone, and is used for measuring the intensity of alternating 

 I'urrents. It consists of a soft iron armature attached to a 

 stretched wire. This executes torsional vibrations w hich are timeil 

 to the period of the alternating current. The latter traverses 

 four electromagnets ranged round the armature, and when the 

 jieriods are identical the armature executes strong torsional 

 vibrations whose amplitude is measured by the width of a slit as 

 seen reflected in a mirror attached to the wire. This arrange- 

 ment is much more sensitive than the electrodynamometer. - - 

 Theory of the broadening of spectrum lines, by B. llalitzin. 

 The nu)lecular theory is superior to those based upon l)op]>ler*s 

 |)rinciple, upon Kirchhoff's law, or upon dam]>ing. It admits 

 "jf a development based upon the electromagnetic theory, that of 

 molecular resonators. The broadening is a consetjuence of the 

 forced vibrations produced by the collision of molecules. The 

 want of synnnelry of the broadening, and tlie influence of 

 temperature and pressure are immediate consequences of the 

 jnolecular theory as developed by the author. 



TllK numbers of the Awr/zd/ ty' /)V>/(i/y/ for August-October 

 contain several articles of interest to descriptive botanists. 

 Mr. K. G. Baker concludes his revision of the African species 

 J if Eriosema, and Mr. A. li. Rendle his description of Mr. 

 -Scott Elliot's tropical .Xfrican orchids, including a large 

 number of new species; Mr. D. Train continues his account of 

 the genus Argtiiwiir : Mr. E. .-\. L. Bailers contributes a 

 list of .Marine .\lg.e new to Hritain ; and Mr. Arthur Bennett 



NO. 1355. VOL. 52] 



.some notes on British Characcv. — There are biographical 

 notices of the late I'rofs. W. C. Williamson and C. C. 

 Babington, with a portrait of the latter. 



AW/. diUa Soc. Sisiiiol. //a!., vol. i., 1S95, No. 5. — .Some ob- 

 servations made on Vesuvius on June 21, 1895, by M. Baratta. 

 — \'esuvian notes (January-June 1895), by (j. Mercalli. — Hydro- 

 thermal observations at Eiumecaldo from January io .\pril 1895, 

 by C. Ciuzzanti. — Notices of Italian earthquakes, .\pril 1895. 

 .\ valuable record of the observations of the first after-shocks of 

 the Laibach earthquake of .\pril 14 from a large number of 

 Italian stations. 



SOCIETIES AND ACADEMIES. 



London. 



Entomological Society, October 2. — Trof. Raphael .Mel- 

 dola, !•'. R.S., President, in the chair. — Mr. .McLachlan 

 exhibited, on behalf of Mr. Bradley, of Birmingham, the 

 specimens of Uiptera attacked by a fungus of the genus 

 Jiiiipusa, of which an account had recently appeared in the 

 Eiifoniologist' s Monthly Magnzim-. — Mr. H. Tunalcy exhibited 

 ; specimens of Lohopliora virclala from the neighbourhood of 

 j Birmingham. .Specimens of the green dark form were shown 

 in their natural positions on the bark, and specimens of the 

 yellow form were shown on leaves on which they rested. — Mr. 

 J. W. Tutt exhibited cases formed by a lepidopterous insect re- 

 ceive<l from the .\rgentine Republic, which he said he recognised 

 as being either identical with, or closely allied to, ThyridoptiTyx 

 cp/ii-iiit:r(,-fonins, which ilid great damage to many orchard and 

 I forest trees in North -America. Mr. Tutt also exhibited a series 

 ai LyCiTiia ctgoii captured by Mr. Massey, of IJidsbury, on the 

 mosses in Westmoreland. The males were remarkable in bear- 

 ing two very distinct shades of colour. The females also differed 

 considerably from the form occurring in the South of England. 

 He also exhibited a long series of .^'(//vA/a /«iVH^, captured in 

 the mosses near Warrington, and for comi>arison a series of 

 Hydnccia paliidis, and he read notes on the various specimens 

 exhibited. — Dr. Eritz- Midler connnunicated a paper entitled 

 " Contributions towards the history of a new form of larva; of 

 I'sychodid.v (Dipteral, from Brazil." — Baron Osten-.Sacken com- 

 municated a paper, supplemental to the preceding one, entitled 

 " Remarks on the homologies and differences between the first 

 stages of I'ericoma and those of the new Brazilian sjiecies."* — 

 The Kev. .\. E. Eaton also contributed some sujiplementary 

 notes to Dr. Fritz-Miiller's paper. — Lord Walsingham, E. R.S., 

 read a paper entitled •' New Species of North .\merican Tortri- 

 cida;. " In this paper twenty-nine species were dealt with, of 

 which twenty-.six were described as new, from I'lorida, Cali- 

 fornia, N. Carolina, -\rizona, and Colorado. The paper also 

 included certain corrections made by the author in the nomen- 

 clature of genera. 



I'AKIS. 



Academy of Sciences. October 7. — M. Jan>sen in the 



chair. — On an ascension to ihe summit of .Mont Blanc, and on 



the work carried out during the suunner of l895on the ** massif* 



of this mountain, by M. J. Janssen. The ascent is described, 



together with an account of the cloud phenomena observe<l 



j during a day in the higher regions. Passing on to describe the 



' 033 m. telescope about to be erected at the observatory, it is re- 



' markeil that the parts, now all assembled at the summit, will be 



mounted as a polar siderostat. .\ O'Om. mirror is to be mounted 



with the telescope. The observer will control all movements 



from a chamber of observation, which will Ix; heated as 



may Ix; required. .\s the instrument could not' Ix: taken 



down anil remounted, it was bodily moved on to a new lase 



1 formed of strong plates frozen on to the ice, and its pendulum 



then beat as regidarlyas at Paris. Observations with a Duboscq 



two-prism spectroscope in this very dry atmosphere failed Io 



j show any rays of aqueous origin in the solar light. The obser- 



I vatory has suffered a slight downwar<l settling towards Cha- 



i mounix ; this took place in 1893 and 1894, and the ntove- 



ment is nosv insignificant. (See Our .\stronomical Column. ) 



— Study of some meteorites, by M. Henri Moissan. Iron from 



I Kendal county in Tex.as contained amorphous carbon, but neither 



graphite nor diamond. Iron from Newstead (Roxburghshire) 



yielded aniorphous carbon and graphite, but not diamond. 



I Deesite, found in 1866 in the Sierra Dees,a in Chili, contained a 



form of graphite only. Caillite, iron from Toluca-Xiquipils.), 



