April 26, 19CX)] 



NATURE 



627 



without absorption, which indicates that the light-producing 

 mechanism is quite different from what it is in flames. — Analysis 

 of oscillating jar discharges by means of the Braun tube, by F. 

 Richarz and W. Ziegler. The authors note A. curious appearance 

 produced in a Braun kathode-ray tube when the fluorescent 

 screen is moved in a direction at right angles to the oscillation 

 of the beam influenced by the discharge. It is a kind of herring- 

 bone structure, in which the slanting ribs are produced by the 

 apparent coalescence of the points of reversal, where the track 

 is brightest and the motion slowest. — A mixture of three 

 powders for producing electric dust figures, by K. Burker. A 

 mixture far superior to the ordinary minium-sulphur combina- 

 tion may be obtained by mixing five volumes of flowers of 

 sulphur with one volume of powdered carmine and three volumes 

 of lycopodium seed. The colours are reversed with respect to 

 the ordinary mixture. — Efi"ect of ultra-violet light upon gaseous 

 bodies, by P. Lenard. The author proves that not only kathode 

 and Becquerel rays are able to make air electrically conducting, 

 produce nuclei of condensation in it, and convert part of it into 

 ozone, but the same efi'ectsare produced, though only to a slight 

 extent, by the extreme ultra-violet rays. The source of light 

 used was the electric spark, but the arc light, and even sun- 

 light, contain some rays effective in this respect. — Quincke's 

 rotations in the electric field, by L. Graetz. Instead of sus- 

 pending spheres of the dielectrics by threads, the author mounts 

 them in the electrolyse on points, so that they have freedom of 

 rotation. The speed of rotation, when it becomes constant, 

 gives a measure of the conductivity of the dielectric. This 

 mode of measurement may be applied to measuring the con- 

 ductivity of air ionised by Rontgen rays. — Electrolytic inter- 

 ruptor for feeble currents, by A. von Rzewuski. If the pressure 

 of the acid upon the anode is increased, the current* is inter- 

 rupted at feebler E.M.F.'s. This is done by either making a 

 current of acid flow against the anode, or by suspending the 

 reservoir of the acid some distance above the anode and con- 

 necting it by a tube. 



In Syinons's Monthly Meteorological Magazine for April, ^Ir. 

 A. B. ^lacDowall draws attention to a curious fact about London 

 summers. Since 1841, the mean temperature of the summer 

 months (June-August) at Greenwich has fluctuated between 

 the extremes 57"'4 and 65"i. If we select all the summers 

 reaching or exceeding 63", and all those reaching or falling 

 below 60°, it will be observed that the hottest summers are 

 nearly all in years ending with the figures 5 to 9, and that the 

 coolest summers are mostly in years ending with o to 4. It 

 would appear, therefore, that the earlier summers in a decade 

 tend to be cooler, and the later summers hotter. The data pre- 

 vious to 1841 are not so trustworthy, but if we take Dr. 

 Buchan's figures as the most dependable, it might be shown 

 that as far back as 1810, at least, the same contrast is indicated. 

 The author of the paper would be glad of any explanation of 

 the cause of this feature in our summer weather. 



SOCIETIES AND ACADEMIES. 

 London. 

 Chemical Society, March 29. — Annual General Meeting. — 

 Prof. Thorpe, President, in the chair. — After the delivery of the 

 presidential address, a ballot was held for the election of officers 

 and council lor the ensuing year. — At an extra meeting held in 

 the evening, Sir H. E. Roscoe, Vice-President, delivered the 

 Bunsen Memorial Lecture. — April 5. — Prof. J. M. Thomson, 

 Vice-President, in the chair. — ^The following papers were read : — 

 The liquefaction of a gas by " self-cooling " (a lecture experi- 

 ment), by G. S. Newth. The author exhibits the liquefaction 

 of nitrous oxioe by rapidly passing the gas from the slightly- 

 warmed storage cylinder through a fine copper tube spiral in- 

 serted in a vacuum-jacketed test-tube. — Note on partially 

 miscible aqueous inorganic solutions, by G. S. Newth. — The 

 decomposition of chlorates. Part ii. Lead chlorate, by W. H. 

 Sodeau. The slow decomposition of lead chlorate by heat 

 consists of the two independent reactions : (i) Pb(C103)~ = 

 PbCl2 + 302,and(2) Pb(C103)2 = PbOj-f Cl.,-l-20.,. Thereaction 

 PbOo + Cl.^ = PbCIa + Go simultaneously proceeds to a greater or 

 less extent. — The bromination of benzeneazophenol, by J. T. 

 Hewitt and W. G. Aston,— A new glucoside from willow-bark, 



NO. 1 591, VOL. 61] 



by H. A. D. Jowett. The author has isolated, from the bark 

 of a species of Sa/ix, the glucoside of metahydroxybenzaldehyde 

 and gives to it the name salinigrin.^Alkylation by means.of 

 dry silver oxide and alkyl iodides, by G. U. Lander. Dry silver 

 oxide and ethyl iodide react with acetanilide yielding ethyl 

 /■-acetanilide, CgHsN : C(OEt)Me.— The interaction of mesityl 

 oxide and ethyl sodiomethylmalonate, by A. W. Crossley. By 

 the condensation of mesityl oxide with ethyl sodiomethyl- 

 malonate, ethyl trimethyldihydroresorcylate, QaHjgOj, is ob- 

 tained ; on hydrolysis it yields trimethyldihydroresorcinol, 



CMe /CHMe.COXcH 



— The products of the action of fused potash on dihydroxystearic 

 acid, by H. R. Le Sueur. 



Entomological Society, April 4.— Mr. G. H. Verrall, 

 President, in the chair. — Mr. M. Jacoby exhibited specimens of 

 the genus Sagra from Eastern Asia. — Mr. M. Burr exhibited 

 three species of Psetidophyllidae, two new species of Capnoptera 

 (females), and Capnoptera qnadriniactilata, Westw. (female), col- 

 lected in the Siamese Malay States by Mr. N. Annandale. The 

 specimens illustrated the peculiar methods of protection adopted 

 by the insect when alarmed. — Mr. H. J. Elwes communicated a 

 paper on " Bulgarian Lepidoptera," and made some remarks on 

 the more notable species which he had taken in the Balkan 

 Peninsula during the months of June and July 1899. The 

 number of species of /\V«^/a/i9f^ra captured was 120, which, with 

 a further 20 recorded by Haberhauer and Lederer, brings up the 

 total to 140. The mountains visited were an extension of the 

 Rhodope range where the climate was particularly rainy, a great 

 number of ferns flourishing everywhere, in contrast to the drier 

 Balkans, where the number of species of Rhopalocera is not less 

 than 200. Some interesting forms but no new species were 

 encountered. A variety of Colias luyrtnidone occurred much 

 larger and brighter than the Austrian, and more nearly agreeing 

 with the Ural, form. The form of Coettony/npha davus met 

 with showed an affinity with the Asiatic and not the European 

 form. The form of Argynnis pales was intermediate between 

 that found in Greece and the central European Alps, while a 

 form of Erebia, var. gorgone, was taken similar to that in the 

 Pyrenees — a curious instance of interrupted distribution. 



Linnean Society, April 5.— IMr. C. B. Clarke, F.R.S., 

 Vice-President, in the chair.— Mr. W. B. Hemsley, F.R.S., 

 exhibited and made remarks on a selection of plants collected 

 by Dr. A. Henry and Mr. W. Hancock in the neighbourhood 

 of Mengtze and Szemao in Western China. — Dr. D. H. Scott, 

 F.R.S., read a paper " on Sphenopliylhim and its allies, an 

 extinct division of the vascular cryptograms." The author 

 explained that his purpose was not to communicate any new 

 observations, but to give a summary of our present knowledge 

 of the group and to discuss its affinities. He pointed out that 

 the study of the Palreozoic Flora not only greatly widens our 

 conception of the three existing classes of Pteridophyta, but 

 adds a fourth — that of the Sphenophyllales — to their number. 

 The various views which have been held as to affinities of the 

 Sphenophyllales were discussed in the light of the results recently 

 attained. The supposed relation to Hydropteridae, though 

 supported by some ingenious arguments, was rejected as base- 

 less, and as inconsistent with the manifest Filicinean affinities 

 of that family. The author came to the conclusion that the 

 Sphenophyllales were most naturally regarded as the derivatives 

 of a synthetic group, combining the characters of Lycopods and 

 Equisetales, and indicating the common origin of these two 

 classes. 



Paris. 



Academy of Sciences, April 17.— M. Maurice Le'vy in 

 the chair. — On the heat of combustion of some very volatile 

 liquids, by MM. Berthelot and Delepine. The method for 

 burning volatile liquids in the calorimetric bomb previously 

 described by the authors involves the use of collodion films, and 

 as collodion is not infrequently dissolved by the vapours of the 

 liquid under examination, a new method has now been devise<l. 

 The liquid is sealed up in a thin glass bulb, which it completely 

 fills, and this bulb is burst in the bomb by a small piece of 

 camphor, the weight and heat of combustion of which are exactly 

 known. Determinations are given for aldehyde, methylal, 

 methyl formate, ethyl formate, propaldehyde and isopropalde- 



