July 12, 1888] 



NATURE 



263 



though it was necessary to introduce numerous modifications of 

 detail and also new modes of experimentation. The bars experi- 

 mented on were of specially prepared wrought-iron and cast-steel ; 

 all the rods were finely polished, and the general physical pro- 

 perties of the metals are given in Table B. Steel bars were em- 

 ployed in some of the experiments, because after magnetization by 

 the coil their subsequent influence as permanent magnets could 

 be observed. The reagents employed as electrolytes consisted 

 of various solutions of bromine, ferric chloride, and chlorine 

 water, ferrous sulphate, ferric chloride, cupric chloride, ctipric 

 iulphate, cupric nitrate, cupric acetate, cupric bromide, nickel 

 chloride, hydrochloric, acid, nitric acid, and potassium chlorate. 

 A pair of bars in each experiment were immersed as elements in 

 the solution in the special apparatus employed, in circuit also 

 with a delicate galvanometer, and after normal galvanic equili- 

 brium had been obtained the bar within the coil was magnetized 

 for various periods and the magneto-chemical effect observed. 

 It was found to vary with the nature of the metal and solution 

 employed, and also with the extent of the magnetization of the 

 metals. The average results of many repeated experiments are 

 given in numerous detailed tables, and it was generally found 

 that a magnetized bar became electro-positive to an unmagnetized 

 one. In Parts I. and II. a total of near 600 iron and steel bars 

 have been experimented upon. Experiments were also made 

 showing that local currents were developed in a magnetized bar 

 between the more highly and less magnetized parts thereof, 

 when the rod was immersed in suitable solutions acting 

 chemically upon it. 



Interesting experiments have also been made in c mnection 

 with the influence of magnetization on the action of strong nitric 

 acid on iron and steel. In course of the research the results of 

 an extensive quantitative study of magneto-chemical phenomena 

 have been recorded, the effect in connection with a considerable 

 variety of typical reagents having been carefully observed ; with 

 some reagents the effect was found to be comparatively small, in 

 other instances it was somewhat considerable. The general 

 conclusion was that under the conditions recorded a magnetized 

 bar was electro-positive to an unmagnetized one, when the two 

 were immersed in suitable solutions, and that the extent of the 

 result was in some degree dependent both on the nature and 

 s 1 rength of the solution, and also on the extent of the magnetiza- 

 tion of the metal. 



June 7. — " Note on the Volumetric Determination of Uric 

 Acid." By A. M. Gossage, B.A. Oxon. 



It seemed improbable that the method recently proposed by 

 Dr. Haycraft for the volumetric determination of uric acid in 

 urine could be accurate, since both Salkowski and Maly had 

 previously shown that the precipitate of silver urate obtained 

 from urine contains variable quantities of other urates. To test 

 the method, I examined samples of various urines both by his 

 method and by that of Salkowski, which is universally acknow- 

 ledged to be the most trustworthy. The mean percentages of 

 uric acid found were as follow : — 



Experiment 

 Haycraft's method 

 Salkowski's method 



I. II. III. IV. V. 



0*108 0*076 0*082 0072 o - io8 

 0084 0035 0051 o oj5 0*084 



The results obtained by Haycraft's method were always con- 

 siderably higher than th^se obtained by Salkowski's. The 

 reason of this is that Dr. Haycraft has assumed that the silver 

 precipitate from urine consists of a urate containing only 1 atom 

 of silver in the molecule, whereas the proportion of silver in 

 silver urate corresponds more nearly to 2 atoms in the molecule. 

 Assuming, then, that there are 2 atoms of silver in all the 

 molecules of the urate, and dividing the results obtained by 

 Haycraft's method by two, we see that the results so obtained 

 are usually lower than those obtained by Salkowski's method, 

 and that the proportion between the results by the two methods 

 varies, as would be expected from Salkowski's researches. 



Edinburgh. 

 Royal Society, June 4. — Dr. John Murray, Vice-President, 

 in the chair. — Dr. G. Sims VVoodhead exhibited a series of 

 photographs of large sections of the lung. — A paper by the 

 Astronomer-Royal for Scotland on Scottish meteorology for the 

 last thirty-two years was read. — Dr. E. Sang read a paper on 

 John Leslie's computation of the ratio of the diameter to the 

 circumference of a circle. — A paper by Lord Maclaren on the 

 figure of aplanatic lenses was read. — Prof. Tait submitted some 

 quaternion notes. 



June 18. — The Hon. Lord Maclaren, Vice-President, in the 

 chair. — The Secretary exhibited M. Amagat's photographs of 

 the crystallization of chloride of carbon under pressure alone. — 

 A paper by Prof. W. Carmichael Mcintosh and Mr. E. E. 

 Prince, St. Andrews' Marine Laboratory, was communicated. — 

 A paper by Prof. Anglin on certain theorems mainly connected 

 with alternants, was read. — Prof. Haycraft and Dr. R, T. 

 Williamson gave a demonstration of a method, which can be 

 used chemically, for estimating quantitatively the alkalinity of the 

 blood. — A preliminary notice of a paper by Dr. G. N. Stewart 

 on electrolytic decomposition of proteid substances was submit- 

 ted. — Papers by Dr. A. B. Griffiths, on the Malpighian tubules 

 of Libelhila depressa, and on a fungoid disease in the roots of 

 Cucumis sativa, were communicated. 



Paris. 



Academy of Sciences, July 2. — M. Janssen, President, in 

 the chair. — Reply to Mr. Douglas Archibald's strictures on the 

 subject of storms, by M. H. Faye. The storm laws, as esta- 

 blished by the observations of Capper, Piddington, Reid, and 

 Redfield, are declared to be one of the greatest disc >veries of 

 the century, and their truth is here vindicated against the recent 

 attacks of Prof. Loomis, Dr. Meldrum, and especially Mr. E. 

 Douglas Archibald, in Nature for June 14 (p. 149). Archi- 

 bald's diagram of the Manilla cyclone of October 20, 1882, is 

 here reproduced, and it is contended that these highly charac- 

 teristic phenomena can be explained only by admitting a 

 descending motion in the central part of the cyclone. But on 

 the opposite supposition it is precisely here that the ascending- 

 current should be strongest, for this central region corresponds 

 exactly to the minimum of barometric pressure. The error in 

 this theory of his opponents is attributed to a confusion between 

 two quite distinct kinds of depressions, a confusion which has 

 for fifty years impeded the progress of meteorological science 

 and increased the perils of navigation. — On the cultivation of 

 Bcemaria in Provence, by M. Naudin. The author reports that 

 the white species (B. nivea), lately introduced from China, 

 thrives well in the Antibes district, where the green variety (/?. 

 utilis) has long been acclimatized. The foliage make-; excellent 

 fodder for cattle. — Automatic control of the velocity in machinery 

 of variable action, by M. H. Leaute. An apparatus, the result 

 of many years' study, is here described, by means of which the 

 action of engines may easily be regulated, even when required 

 to work at varying rates of speed. — On a compass enabling the 

 observer to find the meridian on land or water despite the dis- 

 turbing influence of iron, by M. Bisson. An ingenious appa- 

 ratus is described by means of which the compass may be pre- 

 vented from deviating more than one-tenth of a millimetre, even 

 in the neighbourhood of iron. It has been tested with satisfactory 

 results on board several French ironclads, and works equally 

 well by land or sea. —On the snows, ice, and waters of Mars, by 

 M. Flammarion. In reply to some recent remarks on the 

 meteorological condition of this planet, it is pointed out that the 

 varying state of the polar ice-caps has long been carefully 

 observed by Maedler, Schiaparelli, and others, the inference 

 being that Mars is not in a state of glaciation. On the contrary 

 its temperature is equal to, if not higher, than that of the earth, 

 and its polar snows melt periodically to a far greater extent than 

 on our planet. — On the graphic representation of numerical 

 divisors, by M. Saint- Loup. By adopting a rectangular distribu- 

 tion of the numerals, the author arrives at some practical results 

 on the general grouping of the prime numbers. — On the deter- 

 mination of the constants and of the dynamic coefficient of elas- 

 ticity for steel, by M. E. Mercadier. By the method already 

 indicated (Cumptts rendus, July and August, 1887), the author 



here determines the relation — of the constants for steel. In 



M 

 a future paper will be given the results of the experiment under- 

 taken to determine the coefficients of electricity. — On the 

 mechanism of electrolysis by the process of alternative cur- 

 rents, by MM. J. Chappuis and G. Maneuvrier. The 

 recognized impossibility of electrolysing the sulphate of 

 copper by alternative currents is explained by the theory that 

 the copper deposited on each electrode by one of the currents is 

 immediately dissipated by the inverse current. This explana- 

 tion is here justified by the authors' experiments, which render 

 visible the decomposition of the sulphate of copper, as they had 

 previously done for acidulated water. From this experimental 

 study they hope to deduce the general principles for the prac- 



