No. 107 1, Vol. 42J 



NATURE 



47 



precision and increased stability. — Mr. Goodwin exhibited a form 

 of eye-piece for the microscope which gave a large field with con- 

 siderable magnifying power. — Mr. A. W. Bennett gave a resume 

 of a paper, by Mr. W. West, on the fresh-water Al^cc of North 

 Wales. The paper described a collection of fresh-water Algse, 

 chiefly diatoms and desmids, made in various localities in North 

 Wales and Anglesey, and it furnished what was beyond com- 

 parison the richest list of desmids which had ever been prepared 

 in this country. — Prof. M. M. Hartog's paper, on the state in 

 which water exists in live protoplasm, was read. — A paper 

 descriptive of the method adopted by Mr. Halford in mounting 

 the spermatozoa of the Salmonidae was read, and specimens in 

 illustration were exhibited by the lantern. — Mr. E. M. Nelson 

 exhibited on the screen several slides showing under high powers 

 ( ■ 1350) the bordered pits of Finns and Ttlia. He also ex- 

 hibited a small series of slides to show the qualities of a new 

 apochromatic |-in. objective with fluorite lenses and of 95 N.A., 

 which had recently been made by Messrs. Powell and Lealand. 

 — Mr. Mayall mentioned that the gathering which was to have 

 taken place at Antwerp, in celebration of the 300th anniversary 

 of the invention of the microscope, was unavoidably postponed 

 until next year. 



Paris. 



Academy of Sciences, April 28. — M. Herrnite, President, 

 in the chair. — On a class of differential equations of which the 

 general integral is uniform, by M. Emile Picard. — On the 

 characteristic equation of nitrogen, by M. Sarrau. In previous 

 communications the author pointed out that certain experiments 

 with carbonic acid verified an equation analogous to those pro- 

 posed by Van der Waals and Clausius to represent the relation 

 between the pressure, p, the volume, v, and absolute temperature, 

 T. The following is the equation — 



/ = 



v-a {v- fif ' 



where R, o, 0, K, and « are constants. A discussion of the ex- 

 periments made by Regnault and by Amagat on nitrogen shows 

 that its critical point may also be represented by this formula. — 

 On the heats of formation and combustion of several nitrogenous 

 bodies derived from albumenoid matters, by MM. Berthelot and 

 Andre. The bodies experimented upon are glycollamine or 

 glycocoll, alanine, leucine, tyrosine, asparagine, aspartic acid, 

 and hippuric acid. — Researches on the condensation of benzine 

 and acetylene vapour under the action of the silent discharge, by 

 M. P. Schutzenberger. The benzine condenses into a clear, 

 yellow, resinous .solid. Analyses of the liquid employed and of 

 the condensed product are given, and it is.shownthat the amount 

 of oxygen contained in the latter could not have been taken up 

 from the air, but must have passed through the glass tube. — On 

 GoJiiphostrohiis heterophylla, a coniferous prototype from the 

 Permian of Lodeve, by M. A. F, Marion. — Observation of 

 Brooks's comet (a 1890) made with the Brunner equatorial at 

 Toulouse Observatory, by M. E. Co?serat. — General theory of 

 the visibility of interference fringes, by MM. J. Mace de Lepinay 

 and Ch, Fabry. The consequences which follow from the 

 theorem demonstrated are pointed out, and it is proposed to 

 describe the experiments which verify them in a future com- 

 munication. — On the phosphites and the pyrophosphite of lead, 

 note by M. L. Amat. — The action of erythrite upon the alkaline 

 alcoholates, by M. de Forcrand. The author gives a continua- 

 tion of a previous paper, here discussing formulae for the bodies 

 discovered and giving thermal data which explain the behaviour 

 of the new substances when heated. — The action of lead oxide 

 upon toluene and the production of benzene, by M. C. Vincent, 

 The paper treats of this reaction at temperatures below themelt- 

 int^-point of lead. The conclusions are drawn : (i) that oxide 

 'i( lead attack -i toluene below 335°, giving water, carbonic an- 

 hydride, and benzene ; (2) that, at higher temperatures, less ben- 

 zene and more stilbene and higher hydrocarbons are obtained ; 

 (3) that at a red heat, in addition to the above, hydrocarbons pro- 

 duced by the simple heat decompo-ition of benzene and toluene 

 are obtained ; (4) that diphenyl formed during this experiment 

 in small quantity conies rather from the benzene formed by the 

 action of oxide of lead upon the toluene than from benzene con- 

 tained in the toluene employed.— Thermochemical researches on 

 textile fibres (wool and cotton), by M. Leo Vignon. — Experi- 

 ments relative to the loss and gain of nitrogen by fallow or 

 cultivated land, by M. A, Pagnoul. The writer finds in the 



cases examined that the gain of nitrogen in two years is — (i) with 

 bare soil 29 kg. per hectare ; (2) with grass land 394 kg. per 

 hectare ; (3) with land laid down in clover 904 kg. per hectare. 

 — Note by M. Ant. Magnin, on the parasitic castration of Ane- 

 mone ranunculoidis by Vadium leucospermum. — On the dis- 

 covery of a giant land tortoise at Mont Leberon, by M. Ch. 

 Deperet. — On the action of the positive pole of a constant 

 galvanic current upon microbes, and particularly upon the anthrax 

 bacillus, by MM. Apostoli and Laquerriere. Among the con- 

 clusions drawn are the following : the heating effects of the 

 current may be experimentally neutralized, but the destruction 

 or weakening of vitality of the microbe still takes place ; it is the 

 positive pole only which acts upon the microbes, the negative 

 pole and the intermediate space do not give any evidence of 

 adverse action upon the organisms ; the current sui generis has 

 no effect upon the microbes ; the action at the positive pole is 

 due to the disengagement of acids and of oxygen, as will be 

 shown in a further note. — On the existence of tuberculous endo- 

 carditis, note by M. Raymond Tripier. 



Berlin. 



Meteorological Society, April i.— Prof. Schwalbe, Pre- 

 sident, in the chair. — Dr. Perlewitz spoke on the influence of 

 the city of Berlin on local climatic conditions. To investigate 

 this he had compared, for the year 1889, the meteorological 

 records of two stations outside the city with those of three 

 inside. As regards tempe'-ature, some allowance must be made 

 for the fact that the exposure of the thermometers was not 

 identical at all the stations. The differences in temperature 

 between the city and the surrounding country were greater than 

 for Vienna, the maximal difference showing itself in spring and 

 summer, the minimal in winter. The differences were lea.st at 

 2 p.m., greater at 7 a.m., and greatest at 9 p.m. The absolute 

 humidity was much less inside the city than in the neighbouring 

 country, and the difference was, as regards maxima and minima, 

 the exact reverse of that which held good for the temperature ; 

 whereas, on the other hand, the relative humidity followed the 

 same lines as for differences of temperature. The direction of 

 the wind was generally different in the city from that in the 

 surrounding country, but no definite relationship of the two 

 could be deduced from the observations, and the same held 

 good for the frequency and extent of clouds in the two localities. 

 Thunderstorms were observed less frequently in the city than in 

 the country, but here again it must be borne in mind that the 

 conditions under which observations can be made in the former 

 are much less favourable than for the latter. — Prof. Spcirer 

 spoke on the rotation of the sun, and came to the conclusion 

 that the continued endeavours which have been made to 

 determine the rotation of the sun from observations of sun-spots,, 

 cannot lead to any definite conclusions. 



Physical Society, April 18. — Prof, du Bois-Reymond, 

 President, in the chair. — Prof. Planck spoke on the difference 

 of potential of two binary electrolytes. According to recent 

 views there exists, in any uniform dilute solution of an electro- 

 lyte, a complete dissociation of the ions, the latter being in 

 equilibrium, since the sum of the two electricities of the anions 

 and kathions is equal and the osmotic pre.>-sure is everywhere the 

 same, quite independently of the nature of the ions. The 

 electrical charge of the ions and the osmotic pressure are the 

 sole forces which are at work in the solution, and suffice to 

 account for all the phenomena which take place inside it. But 

 in order to calculate the above it is necessar}' to know the 

 mobility of the ions ; this has been determined experimentally 

 by Kohlrausch for a large number of different ions, and he has 

 also measured the electrical charge of the ions, this charge being 

 independent of their nature. If the solution is not of uniform 

 composition, the osmotic pressure leads to a movement of the 

 ions from the more to the less concentrated parts of the solution. 

 Now, since the mobility of the ions varies, being five times as 

 great for hydrogen as for chlorine, it follows that a larger number 

 of hydrogen atoms will pass from the more concentrated parts of 

 the solution, than of chlorine. This, however, leads to an up- 

 setting of the electrical equilibrium, and the electrical affinities 

 work m a direction opposite to that of the flow of atom'--. The 

 speaker had developed a general mathematical formula to ex- 

 press what takes place in the case of two solutions of different 

 concentrations which are in contact with each other through an 

 intervening porous partition. By means of this formula he has- 



