July 14, 1892] 



NATURE 



163 



Tower, and their exact time of describing certain distances was 

 measured to a hundredth of a second by means of an electric 

 chronograph. The body was fixed to a very light thread wound 

 round a set of inverted cones, each of which held 20m. of thread. 

 The latter passed from one cone to another through two fine 

 springs in contact, which contact was broken by the string 

 pulling through, thus producing a mark on the chronograph. 

 The retardation produced by the string was independently de- 

 termined and found to be less than oooi percent. The follow- 

 ing laws were verified : that the resistance of the air is 

 proportional to the area of the resisting surface ; and that it is 

 independent of the form of the surface. That it is also pro- 

 portional to the square of the velocity was not found to be 

 strictly true, since the resistance increased rather more rapidly. 

 The amount of fall after which the velocity of the weights em- 

 ployed became uniform ranged from 6om. to loom. Contribu- 

 tion to the study of the function of camphoric acid, by M. A. 

 Haller. — A new contribution to the history of morbid associa- 

 tions ; anthrax and paludism, by M. Verneuil. — Fixation of 

 ammoniacal nitrogen on straw, by M. de Vogiie. — On the 

 nature of the rotation of the knife-edge of a pendulum on its 

 plane of suspension, by M. G. Defforges. This rotation is not 

 a simple rolling, as was assumed by Euler and Laplace, but is 

 compounded with a sliding motion, whose existence can be 

 proved by means of interference fringes. The sliding is pro- 

 portional to the amplitude and up to six or seven kgr. to the 

 weight. — On the influence of the place of the external ther- 

 mometer in observations of zenith distances, by M. Perigaud. 

 In calculating the error due to refraction by Arago's method, 

 the density of the layer of air in the neighbourhood of the 

 objective is measured by a thermometer placed outside the 

 room, near the north side of the observatory. It was sought to 

 fulfil the conditions of the problem more rigidly by suspending a 

 thermometer quite close to the objective. The zenith-distances, 

 calculated on the basis of its indications, showed a difference of 

 0-2 too*8 from those obtained by Arago's method, which made 

 the zenith distances too large. The writer's method has been 

 adopted at the great transit-instrument of the Paris Observatory. 

 — On the primary forms of linear differential equations of the 

 second order, by M. Ludwig Schlesinger. — On the precise 

 determination of the critical density, by M. E. Mathias. This 

 determination is aided by the law of the rectilineal diameter, 

 according to which in the curve of temperatures and densities 

 the locus of the midpoints of the chords parallel to the axis of 

 the ordinates is a straight line. This law, recently confirmed by 

 Young's experiments, implies that the critical density is equal to 

 the ordinate of the diameter which corresponds to the critical 

 temperature. Calculated according to this law, the critical 

 densities of methyl, ethyl, and propyl alcohol are found to be 

 the same. — Influence of the mass of the liquid in the 

 phenomena of heating, by W. A. Witz. — Measurement of the 

 dielectric constant by electromagnetic oscillations, by M. A. 

 Pt-'rot. By the method described, the constant K was deter- 

 mined for glass, and found to range from 271 if charged for 

 726 X 10-'" sec. to 5727 if charged for 4537 x 10-'" sec. — On 

 the composition of water and Gay-Lussac'e law of volumes, by 

 M. A. Leduc. The writer's researches on the densities of gases 

 have led him to adopt the value 23'24 for the percentage of 

 oxygen in the air. The density of oxygen was determined by a 

 modification of Dumas's process, in which the hydrogen was 

 absorbed by finely-laminated electrolytic copper. The atomic 

 weight deduced was IS"88, while the mean of the best values 

 for the density is 1 5 '90. This shows that Gay-Lussac's law of 

 volumes is only approximate. — On the nitrogen salts of platinum, 

 by M. M. Vezes. — Researches on the sodic pyrogallols, by M. 

 de Forcrand. — On acetono-resorcine, by M. H. Causse. — 

 Utilization of roasted iron pyrites for the manufacture of iron 

 salts, by MM. A. and P. Buisine. — On the alterations of ferru- 

 nous waters, by M. F. Parmentier. — Reproduction of pure 

 assic nepheline, by M. Andre Duboin. — On the passage of 

 -solved substances through mineral filters and capillary tubes, 



I by M. C. Chabrie. — On haemocyanine, by M. Leon Fredericq. 



I — On the physiological determinism in the metamorphosis of 

 the silk-worm, by M. E. Bataillon. — On a new Teinnocephala, 

 parasite of Astacoides madagascariensis, by M. A. Vayssiere. 

 1 arthworms and tuberculosis, by MM. Lortet and Despeignes. 

 .laving that worms can bring the bacillus to the surface, pre- 

 serving all its virulent properties. — On the Californian disease, 

 a disease of the vine caused by Plasmodiophora calif ornica, by 



NO. I 1 85, VOL. 46] 



MM. P. Viala and C. Sauvageau. — An essay on vegetable 

 statics, by M. Augustin Letellier.— On the cavern called the 

 Creux de Souci (Puy-de-Dome), by MM. E. Martel, A. Dele- 

 becque, and G. Gaupillat. — On the lakes of the central plateau 

 of France, by MM. A. Delebecque and E. Ritter. 



Berlin. 



Physical Society, June 3.— Prof. Schwalbe, President, in 

 the chair. — Dr. Gross continued his remarks on the subject of 

 entropy. — Dr. Wien gave an account of experiments on the 

 measurement of high temperatures, made in conjunction with 

 Dr. Holborn, with a view to testing Le Chatelier's platinum 

 and ihodium thernio-elements. They were first compared with 

 an air-thermometer. The latter consisted of a glazed porcelain 

 tube containing slightly rarefied air, the temperature being 

 recorded by a manometer. The thermo-element was introduced 

 into the cavity of the air-thermometer, and the readings of the 

 respective instruments were compared between -80° and -f 

 1500°. Below 500° the thermo- element was not very sensitive, 

 and is hence of use only for high temperatures. Alloys of 

 platinum with 9, 10, 11, 20 and 40 per cent, of rhodium were 

 tried. It was found that the E.M.F. increased with the in- 

 creased percentage of rhodium, but that the most suitable alloy 

 was that containing 10 per cent, of rhodium as recommended by 

 Le Chatelier. The above experiments necessitated the determi- 

 nation of the co-efficient of linear expansion of Berlin porcelain. 

 This was found to be •000004. In some final experiments the 

 melting-point of gold was determined to be 1073° and 1067°, of 

 silver 972" and 968°, and of copper 1082°. 



June 17. — Prof. Kundt, President, in the chair. — Prof. Vogel 

 exhibited a remarkably fine series of coloured prints of oil 

 paintings, &c., prepared in accordance with his method by 

 Messrs. Vogel and Ulrich. The method consists in first taking 

 a red, a yellow, and a blue negative of the object on plates 

 specially sensitized for colours. The three negatives are then 

 printed on to one and the same paper by means of comple- 

 mentarily coloured rollers or stones. In order to obtain the 

 colours exactly complementary to those of the negatives, the 

 colours used for printing were either the coloured sensitizers 

 themselves or some substance whose equivalence to these had 

 been determined spectroscopically. The application of the 

 physical principles involved in the above yielded an approxi- 

 mate reproduction of the natural colours which was surprisingly 

 complete, and will become more so as more and more coloured 

 substances are discovered suitable as sensitizers. — Prof. Koenig 

 described his new spectrophotometer. Its chief improvement 

 consists in the introduction of Lummer and Brodhun's glass- 

 cube, which is, however, so modified as to admit of the measure- 

 ment of the relative intensities of the parallel rays falling into it. 



Physiological Society, June 24. — Prof, du Bois Raymond, 

 President, in the chair. — Prof. Kossel communicated the results 

 of some experiments made by Dr. Monti on the absorption of 

 oxygen by the tissues after death, using for this purpose their 

 reducing action on photographic plates. The suprarenals, 

 spleen, and thymus reduced most actively, while brain- 

 substances produced but little effect. Dr. Lilienfeld had in- 

 vestigated the distribution of phosphorus in various tissues by 

 means of micro-chemical reactions with ammonium molybdate 

 and pyrogallol. The presence of phosphorus was usually 

 strongly marked in the nuclei as compared with the cell- 

 substance, except in the case of the cerebral ganglia, in which 

 the reverse was frequently observed. Prof. Gad drew attention 

 to a phenomenon, brought to his notice by Prof. Litten, which 

 may be observed during normal human respiration, and consists 

 in the downward passage of an obvious wave over the wall of 

 the thorax at each inspiration aud the upward passage of a 

 similar wave at each expiration. 



Amsterdam. 



Royal Academy of Sciences, June 25. — Prof, van der 

 Waals in the chair. — Prof. T. Forster spoke (i) On the action 

 of heat upon tuberculous matter. According to former investi- 

 gations by " pasteurizing" [i.e., warming liquids to a temperature 

 of 60 to 80° C. for a short time and cooling them immediately), 

 bacteria of Asiatic cholera and typhoid-fever are killed at about 



