June 4, 1903] 



NATURE 



17 



fugalised and the deposit examined microscopically. This 

 spe.-ies of trypanosoma seems to differ from that found in j 

 human trypanosomiasis (7". Gamhiense, Dutton) by being 

 less motile, by the micro-nucleus being situated nearer the 

 extremity, and by the vacuole being larger. Should it prove 

 to be a new species, the author suggests that it should be 

 named the Trypanosoma Ugandense. The author had 

 previously isolated a streptococcus in this disease ; he now 

 suggests as a working hypothesis that sleeping sickness | 

 is due to a trypanosoma, and that in the last stages there is 

 a concomitant streptococci infection. 



In a note to this communication the secretary of the 

 Royal Society (Sir M. Foster) states that a telegram has 

 been received from Colonel Bruce, who is continuing Dr. 

 Castellani's investigations in Uganda, announcing that he 

 has found trypanosomes in the cerebro-spinal fluid in every 

 one of thirty-eight cases examined, and in the blood in 

 twelve out of thirteen cases. 



Physical Society, May 22. — Dr. R. T. Glazebrook, 

 F.R.S., president, in the chair. — Mr. J. Stttttner gave an 

 exhibition of Nernst lamps, showing their development from 

 the experimental form up to the most recent types. The 

 oxides used for the glowers are thoria, zirconia, and other 

 rare earths thereto related, such as oxides of yttrium and 

 cerium. A paste of these is formed, and small rods or tubes 

 are pressed through a suitable nozzle. These are hardened 

 and cut into small lengths, and practically the principal 

 part of the lamp is finished. The chief difficulty in the 

 practical lamp is in the design of a durable automatic heater 

 to heat the filament up to conducting point. A number 

 of automatic arrangements which have been designed for 

 disconnecting the heater were shown. Another important 

 part of a Nernst lamp is the bolstering resistance, which 

 in its final development consists of a thin iron wire sealed 

 in a glass bulb filled with hydrogen gas. If a lamp is used 

 without a bolstering resistance, as soon as a certain critical 

 potential is reached the current increases, at first slowly and 

 then quicker and quicker, the potential remaining constant, 

 until the lamp burns itself out. — Mr. T. H. Blakesley 

 gave an exhibition of a diagram for single-piece lenses. 

 The properties of a single-piece lens are determined by four 

 factors : — the two radii of curvature, the thickness of the 

 lens, and the value of the refractive index of the material of 

 which it is composed. In the case of a lens of a particular 

 thickness made of a material of definite refractive index, 

 the variables reduce to two, namely, the ratios of the radii 

 of curvature to the thickness of the lens. Any property of 

 the lens requires a relation between these quantities. It is 

 therefore possible, for any property, to draw a curve, with 

 r,/d as ordinates and r^/d as abscissae, such that any point 

 on the curve represents a lens having that property. Mr. 

 Blakesley has drawn curves representing several properties. 

 Where two curves cut there is a point which gives a lens 

 having the properties due to both curves. By means of 

 such a diagram various lenses have been constructed, and 

 three of them were shown at the meeting. Of these, one 

 was equivalent to a Huyghens eye-piece and another to a 

 collimator. — A paper on an instrument for measuring the 

 lateral contraction of tie-bars, and on the determination of 

 Poisson's ratio, was read by Mr. J. Morrow. Practical 

 methods for the determination of the ratio of lateral to 

 linear strain in a tie-bar may be divided into three classes. 

 First, those in which two coefficients of elasticity are deter- 

 mined and Poisson's ratio calculated; second, those depend- 

 ing on the deformation of the section of a beam ; and lastly, 

 methods by which the two strains are actually measured. 

 The experiments described in the paper belong to the third. 

 From a table of results, it appears that the average values 

 of <r are for mild steel 0275, Sheffield spindle steel 0276, 

 wrought iron 0277, Muntz metal 0341, and drawn copoer 

 I. ,27. The specimens were not annealed, and were mostly 

 about one inch in diameter. For the experiments on cast 

 iron, two series of specimens were carefully cast of material 

 of good average quality. These were loaded several times 

 in order to eliminate permanent set. The first series gave 

 an average value <r =0246 and the second <r =0-252. 



Chemical Society, May 20 —Prof. W, A. Tilden, F.R.S., i 

 pif'sident. in the chair.— The following papers were read :— 

 riio conditions of decomposition of ammonium nitrite, by 

 \'. II. Veley. The decomposition of ammonium nitrite into 



NO. 1753, VOL. 68] 



nitrogen and water proceeds according to the general law 

 log. A/A — x — afi, whether the reaction follows its normal 

 course or is accelerated by the addition of another sub- 

 stance. The decomposition is either impeded or stopped 

 by ammonia, aliphatic, benzenoid or pyridine amines and 

 aromatic hydrazines, and to a less degree by oximes, but 

 is accelerated by aliphatic amides. — Freezing point curves 

 for some binary mixtures of organic substances, chiefly 

 phenols and amines, by Dr. J. C. Philip. When freezing 

 point curves for mixtures of two substances are constructed 

 two types are obtained : — (a) a curve consisting of two 

 branches, starting from the freezing points of the con- 

 stituents and cutting each "other at a eutectic point; (6) the 

 two branches are cut by a third intermediate curve, which 

 may sometimes have a summit. Examples of the latter 

 type have been found for the systems phenol — urea, p-cresol 

 — aniline, phenol — a-naphthylaniine , phenol — p-toluidine, 

 a-naphthol — p-toluidine, phenol — picric acid. — Isomeric 

 partially racemic salts containing quinquevalent 

 nitrogen. Part xi. Derivatives of ti/-methylhydrindamine 

 and d/-neo-methylhydrindamine. Isomeric salts of the type 

 NR,R2H3, by G. Tattersali and F. S. Kippinar. A de- 

 scription of these compounds was given. — The action of 

 liquefied ammonia on chromic chloride, by W. R. Lang^ and 

 C. M. Carson. In this reaction a salmon-coloured powder 

 is produced from which water extracts two unstable, crystal- 

 line compounds with the formulae Cr2Cl5,i2NH3,2HjO and 

 Cr^Clj.ioNH,. — ^Note on the action of methylamine on 

 chromic chloride, by W. R. Lang and E. H. Jolliffe. The 

 reaction is similar to the foregoing, the product being a 

 pink substance of the composition Cr2Clj,ioCH3.NH,. — 

 Cholesterol, by R. H. Pickard and J. Yates. The oxida- 

 tion and hydrolytic products of cholesterol obtained from 

 gall stones have been studied ; among the former is arachidic 

 acid. — Sulphocampholenecarboxylic acid, by Messrs. Hardy 

 and Lap^orth. — Optically active esters of ;8-ketonic and 

 )3-aldehydic acids. iii. Azo-derivatives of menthyl aceto- 

 acetate, by A. Lapworth. — Hydrogen cyanide in fodder 

 plants, by J. C. Briinnich. The observation of Dunstan 

 and Henry that the amount of prussic acid producible from 

 the Sorghum plant increases as the plant matures and de- 

 creases after the production of seed has been confirmed by 

 a, series of determinations of the prussic acid obtainable from 

 manured and unmanured plants at all stages of growth. — 

 The chemical reactions involved in the rusting of iron, by 

 Prof. W. R. DMnstan, F.R.S. It is shown that the 

 presence of liquid water and oxygen is necessary for the 

 formation of iron rust ; this action is merely accelerated, not 

 conditioned by the presence of carbon dioxide. No rusting 

 occurs when pure iron is kept in presence of oxygen and 

 water vapour at constant temperature ; the rusting of iron 

 is prevented by the presence of solutions of such salts as 

 decompose hydrogen pero.xide, whilst its formation is not 

 inhibited in solutions of salts in presence of which hydrogen 

 peroxide is stable. The deduction is therefore drawn that 

 hydrogen peroxide is the active agent in the production of 

 iron rust. 



Geological Society, April 29.— Mr. J, J. H. Teall, F.R.S., 

 vice-president, in the chair. — The age of the principal lake- 

 basins between the Jura and the Alps, by Dr. Charles S. 

 Du Riche Preller. The author deals with the question 

 reserved from a preceding paper, that is, to which subse- 

 quent period the formation of Swiss lake-basins should be 

 assigned. By the light of further recent investigations in 

 the different localities, he first considers the conditions of 

 the Zurich lake-valley, and then applies his conclusions to 

 the other principal lake-basins lying in the same zone along 

 the edge of the Alps. Evidence is adduced to show that the 

 deep-level gravel-beds in the Limmat Valley near and below 

 Zurich are essentially fluviatile, composed of the charac- 

 teristic Alpine material of the Rhine and Linth drainage- 

 areas, and similar to the gravel now carried by the River 

 Sihl. Ihese gravel-beds rest upon Glacial clay of the second 

 glaciation, which fills the Molasse-bed "of the valley to a 

 great depth, and are overlain by the moraine-bars of the 

 third glaciation, the latter being overlain by the post-Glacial 

 alluvia of the Sihl. On mechanical grounds, it is difficult 

 to conceive how glaciers could either bridge or completely 

 fill with ice such extensive basins as those of the principal 

 .\Ipine lakes. .'\s regards the more recently enunciated , 



