November io, 1904] 



NA TURE 



47 



poisons may act are discussed in the paper, and it is 

 suggested that in many cases they enter into chemical com- 

 bination with the enzyme. 



Royal Microscopical Society, October 19.— Dr. Dukin- 

 field H. Scott, F.R.S., president, in the chair.— A com- 

 munication from Mr. W. D. Colver described the antennx 

 of Fidex irritant, on the terminal joint of which Mr. Win. 

 Jenkinson, of Sheffield, had discovered a lamellated struc- 

 ture that he believed to have an olfactory function. Mr. 

 Jenkinson had found similar structures in several other 

 members of the family Pulicida;. A slide showing the 

 entire antenna, and another showing the terminal joint, 

 were exhibited under microscopes, and photographs of the 

 latter slide were exhibited in the room and on the screen. 

 — Part xvii., being the concluding part, of Mr. Millett's 

 report on the recent Foraminifera of the Malay Archipelago 

 was taken as read. — The President then gave a demonstra- 

 tion on the reconstruction of a fossil plant. The plant 

 selected was Lyginodendroii Oldhamium. The growth of 

 our knowledge of its construction was illustrated by a 

 number of actual sections and lantern slides shown on the 

 screen. The identification of the stem of a Pinites, the 

 fern-like petiole of Rachiopieris aspera, and the foliage of 

 Sphenopicris Honinghaiisi as being corresponding parts 

 of Lyginodendron was demonstrated. It was discovered 

 that the stem was frequently branched, and certain fossil 

 seeds are now, on structural evidence and association, con- 

 sidered to be the fruit of this plant. The reconstruction 

 of the plant is, however, still incomplete, for the male 

 organs have not yet been identified with certainty. The 

 position of Lyginodendron as a seed-bearing plant allied at 

 once to cycads and ferns was now established. A picture of 

 the reconstructed plant was shown on the screen, and 

 models of the seed lent by Prof. F. W. Oliver were exhibited. 

 Physical Society, October 28. — Dr. R. T. Glazebrook, 

 F.R.S., president, in the chair. — An interference apparatus 

 for the calibration of extensometers : J. Morrow and E. L. 

 Watkin. The paper describes an apparatus for calibrating 

 extensometers and similar instruments by comparison with 

 the wave-length of sodium light. The apparatus is self- 

 contained and easily made ready for use. It consists 

 essentially of two metal cylinders of equal diameter, with 

 their axes in the same straight line, but with a small gap 

 between their adjacent ends. The gap is increased or de- 

 creased by the movement of a lever actuating a screw, and 

 the alteration in its amount is measured by the interference 

 rings produced in an optical system situated inside the gap. 

 --.\ sensitive hygrometer: Dr. W. M. Thornton. The 

 instrument is made by enclosing the cooled surface of a 

 Regnault's hygrometer in a glass globe so that only the 

 mass of vapour contained in the vessel is available for con- 

 densation. The cooled surface is made much smaller than 

 usual — about i sq. cm. The surface-density of the deposited 

 moisture depends on the total quantity of water-vapour pre- 

 sent. If this is more than a minimum to be determined 

 later, it will be visible either by the loss of brightness by 

 scattering, or by observing, as in the Dines hygrometer, 

 the scattered light itself. Little is known as to the manner 

 in which moisture is deposited on smooth cold surfaces. 

 Dr. Park has shown that the thickness of the deposit is 

 of the same order as that of the black spot in interference 

 lilms. The reflection of light from such a clear layer of 

 uniform thickness backed by a bright surface is considered 

 in the paper, and it is shown that the loss of light due to 

 the thinnest possible films can be perceived. The opposite 

 case to that of a smooth layer is that of clear spherical 

 particles resting on the surface. This is also considered, 

 and the surface-density to give a visible deposit is calcu- 

 lated. In connection with this an interesting note was re- 

 ceived from Lord Rayleigh in reply to an inquiry, in which 

 he shows that the maximum brightness of a cloud is about 

 4x10-^ that of the sun. Comparing all values, it is taken 

 that 10- ' grams per sq. cm. can be detected by unaided 

 \ision with diffused light. The time taken for moisture to 

 diffuse from a state of uniform distribution throughout the 

 globe towards the centre is then calculated, and found to 

 be less than ten minutes for a sphere of :!o cm. diameter. 

 The paper is an attempt to make the somewhat neglected 

 Regnault hygrometer an instrument of precision in the 

 detection of small quantities of moisture. — ;\ote on 



NO. 1828, VOL. 71] 



a property of lenses: Dr. G. E. Allan. A well 

 known method of testing the concavity or convexity of 

 a lens consists in holding the lens at arm's length and, 

 while looking through it, moving it from side to side or 

 up and down, when the image in the convex lens is found 

 to move in the opposite direction to that of the lens, whilst 

 in the case of the concave lens it moves in the same direction. 

 The above facts hold if, instead of the naked eye, we employ 

 a microscope. 



P.ARis. 



Academy of Sciences, October 31. — M. Mascart in the 

 chair. — Presentation of vol. xi. of the " Annales de 

 rObservatoire de Bordeaux " : M. Loewy. — Trypano- 

 somiasis in French West Africa : .\. Laveran. The sleep- 

 ing sickness is endemic in several regions of Senegal ; an 

 examination of six specimens of biting flies from this district 

 showed that they were all Glossiim palpalis, the fly which, 

 according to the researches of Dr. Bruce, propagates human 

 trypanosomiasis. In the blood of horses from French 

 Guinea, in two cases numerous trypanosomes were 

 encountered. In the flies from this region, Glossina palpalis 

 predominated. On the Ivory Coast, sporadic cases of 

 human trypanosomiasis are common ; here one specimen of 

 G. palpalis was found, together with several G. morsitans. 

 Round Lake Tchad numerous trypanosomes, having the 

 characteristics of Trypan. Brucei, were found in the blood 

 from infected horses ; G. tachinoides here appears to be the 

 characteristic tsetse fly. — On a case of long phosphorescence 

 emitted by the wood of a cherry tree : M. Clos. — The 

 rotation of Venus : P. Lowell. The results of spectro- 

 scopic observations show a velocity of about 0005 kilometre 

 a second, which favours a long period of rotation. 

 For a twenty-four hour period, the velocity would 

 be 0450 kilometre a second. — The rotation of Mars : 

 P. Lowell. The spectroscopic measurements give a 

 velocity of 0228 kilometre per second, as against 0241 

 kilometre calculated from the previous eye observations. — 

 On a new micrometer. History of the question : G. 

 Millochaii. An account of previous applications of the use 

 of parallel glass plates as a micrometer. — On a new safety 

 arrangement for electrical mains at high tension : L. Neu. 

 Each line is furnished' at its source with an interrupter 

 which works automatically in the case of a wire breaking, 

 of a bad insulation, or in the event of an accidental contact 

 between the high tension wire and a telegraph or telephone 

 wire. — On the atomic weight of aluminium : M. Kohn- 

 Abrest. .\luminium, the impurities in which had been 

 determined by analysis, was treated with acid, and the 

 evolved hvdrogen burnt to water. The mean of seven experi- 

 ments gave 99- 15 parts of water from 100 parts of the pure 

 metal, corresponding to an atomic weight for the aluminium 

 of 2705 (oxvgen, 15.88).— The action of halogen derivatives 

 of the metalloids on halogen alkyl compounds : V. Augrer. 

 The alkyl iodides, bromides, and chlorides react with phos- 

 phorus "iodide, giving alkylphosphinic acids. No reaction 

 occurs with the chloride of arsenic ; chloride of bismuth 

 simply gives rise to an exchange of halogens, whilst with 

 chloride of antimonv the quantity of antimony-alkyl was 

 too small to separate.— The tetrahydride and decahydride 

 of naphthalene : Henri Leroux. these addition products 

 were obtained from naphthalene by means of the Sabatier 

 and Senderens reaction. Their properties and those of some 

 halogen derivatives are described. — The action of the 

 chlorides of phosphorus on the organoinagnesium compounds 

 of the aromatic series : R. Sauvage. The action of phos- 

 phorus oxychloride upon organomagnesium compounds of 

 the aromatic series leads to the production of compounds 

 of the type R, : P : O and R.. = POCl, the latter, after treat- 

 ment with water, giving acids R, = PO.OH. The tetraoxy- 

 cyclohexane-rosanilines : Jules Schmidlin. The author 

 quotes some experiments of Lambrecht and Weil as affording 

 a new confirmation of his views on the quinonic structure 

 of these compounds, and also as showing that the benzene 

 ring of the carbinol passes through the hexahydrobenzene 

 ring before forming the quinone ring. — The density of nitrous 

 oxide and the atomic weight of nitrogen : Philippe A. Guye 

 and Alexandre PIntza. The nitrous oxide used in these 

 experiments was prepared from sodium nitrite and hydroxyl- 

 amine sulphate. .After weighing the flask full of the gas, 

 the latter was condensed by connecting the flask with a 



