January 30, 1902] 



NATURE 



303 



pouring mercury into the long arm. The method is still used for 

 demonstration purposes, but it has certain disadvantages. One 

 of these — namely, the fact that the pressure diminishes as the 

 water passes into the plant — the author now proposes to remove 

 by the use of the apparatus described in a paper on the hydrosi- 

 meter (Amsterdam Academy of .Sciences, vol. iv. , November 

 1901). The arrangement by which this is effected is simple 

 and practical, and may no doubt be useful in other cases where 

 it is desired to subject a plant to prolonged and constant 

 pressure. The paper is illustrated by a drawing of the apparatus, 

 and has the merit of being written in English. 



Light electric motor carriages, or "runabouts" as the 

 Americans have termed this type of vehicle, were a feature of 

 the recent exhibition of automobiles held in New York. 

 According to the Electrical World and Engineer, the Electrical 

 Vehicle Co. of New York was represented by a light car of this 

 type weighing only 394 kg. and provided with a battery of the new 

 Exide cell, capable of driving the carriage 64 km. at a speed 

 of 22 km. per hour. The American Bicycle Co. exhibited an 

 electrical carriage weighing 450 kg. The battery in this case 

 was composed of thirty cells, and was of sufficient power to 

 drive the vehicle for four hours at the rate of 27 km. per 

 hour. The Baker Motor Vehicle Co. showed a light ^' Stan- 

 hope " weighing 405 kg., provided with a battery of ten 

 Plantc cells, capable of driving the carriage 64 km. on one 

 charge. The battery weighed 140 kg. It would have been 

 interesting to know the average life of the plates in these bat- 

 teries under normal road and running conditions, but upon this 

 crucial point nothing is said in the report before us. In large 

 towns, where several generating stations exist, and where the 

 recharging of exhausted batteries is a comparatively simple 

 affair, we believe there is a useful future before this type of 

 motor-vehicle. 



Prof. P. Zeeman, in a paper recently read before the 

 Amsterdam Academy of .Sciences, (November 30, 1901), stated 

 that he had been investigating the limits of resolving power 

 attainable by means of the Michelson Echelon grating spectro- 

 scope, with an instrument consisting of thirty plates, each 7 "8 

 mm. thick, set at steps of I mm. Testing by means of light 

 sources in magnetic fields of gradually increasing intensities, 

 he found that the resolving power was almost equal to its 

 theoretical value. 



In a paper on the energy of the universe in the Revue 

 scienlifiqtie, M. I. Skvortzow discusses the influence of electrical 

 phenomena in cosmogony. lie considers that in the past 

 history of the earth, and of other celestial bodies, electrical and 

 chemical energy have originally played the most important 

 part, and that heat energy has become more and more important 

 in proportion as the earth has assumed a more material form, 

 so that the more its energy has passed from the dynamic to the 

 static form the greater has been the absorption of dynamical 

 energy in overcoming resistances. The heat of the earth M. 

 Skvortzow attributes to electric currents circulating mostly 

 near the surface ; the interior of the earth, on the other hand, 

 he thinks may be as cold as the greatest depths of the ocean. 

 Changes in the aspect of the earth, as well as meteorological 

 phenomena, are attributed to electric currents induced by solar 

 influence. The temperatures of different planets are considered 

 to depend less on their distance from the sun than on their reserve 

 of energy and on the currents which the sun induces in them in 

 virtue of their axial and orbital motions. Will this theory of 

 the electromagnetic origin of the earth's heat reconcile the two 

 opposing views on the age of the earth ? 



The somewhat heated controversy which ensued at the 

 beginning of last year on the occasion of the starting of the 

 NO. 1683, VOL. 65] 



London United Tramway's electrical system has borne after-fruit 

 in the paper on earth currents derived from distributing systems 

 which was read last Thursday before the Institution of Electrical 

 Engineers by Mr. E. B. Wedmore. The author treated the 

 subject of the magnetic disturbance caused by the currents leaking 

 from the rails of a rail-return tramway system from a mathema- 

 tical and practical point of view, and also discussed briefly the 

 electrolytic troubles that may arise. To judge by the paper itself 

 and the discussion, which was of a very quiet nature, the whole 

 subject is in need of further investigation. This applies, 

 perhaps, more particularly to the question of the electrolysis of 

 gas and water pipes. With most of the speakers it seemed to 

 be an article of faith that the leakage currents under Board of 

 Trade rules will not do any damage worth considering, but ex- 

 perimental evidence, which is doubtless very difficult to procure, 

 is wanting. There still remains to be explained the presence of 

 the fifteen amperes which were found flowing in the London 

 United Tramways' rails before the system had started electrical 

 working, and it is not to be wondered at if facts such as these 

 make gas and water engineers feel uncomfortable. Another point 

 brought out by two speakers is worthy of notice ; the term earth 

 currents has for long definitely meant the cosmic phenomena, 

 and should not be applied to the leakage currents from tram- 

 ways, or else confusion is sure to result. 



The Dumoulin process for the electro-deposition of copper in 

 the form of tubes does not appear to have been very successful 

 at Widnes, where a works for operation of this process was 

 built in 1896-1897. According to the fifth annual report of 

 the Electrical Copper Co., it has been decided to close the 

 works permanently and to sell the plant, since at no period of 

 its operation has a profit been earned. This failure to earn 

 profits is ascribed, to the small output — only thirty tons per 

 month, to the high price of fuel, and to the heavy interest 

 charged on the loans raised by the company. The directors in 

 their last report, however, still speak confidently of the value of 

 their patents (which stand in their balance-sheet at 405,000/.), 

 and negotiations are to be opened for the sale of these to 

 refiners able to work the process on a larger scale of operations. 

 We may remind our readers that the Dumoulin process depends 

 upon the electro-deposition of copper upon revolving mandrils ; 

 specially treated strips of skin being used to supply the friction 

 necessary for obtaining smooth and dense deposits. The process 

 differs from the well-known Elmore process chiefly in this sub- 

 stitution of skin for agate burnishers ; and it is noteworthy that 

 in neither case has the financial success realised the early ex- 

 pectations of the promoters of the companies operating these 

 processes. 



A REPORT on the Kampur coal-field, which lies in the Central 

 Provinces of India, north-west of Sambalpur, has been pre- 

 pared by Mr. G. F. Reader {Mem. Geol. Survey, India, vol. 

 xxxii. part ii.). A good steam coal, 7 feet 10 inches thick, and 

 two other seams of workable coal, have been proved to exist. 

 Their extension has, however, to be determined. 



We have received from Mr. A. Gibb Maitland, Govern- 

 ment Geologist, the annual progress report for 1900 of the 

 Geological Survey of Western Australia. A detailed geo- 

 logical map of Kalgoorlie has been prepared and will be 

 published together with a full report on the geology of 

 this important mining centre. The lodes are for the most part 

 bands of basic rocks, which are characterised by strong foliation, 

 by the alteration of amphibole into chlorite and carbonates of 

 iron, lime, manganese and magnesia, and, finally, by the de- 

 velopment of secondary silica, mica, pyrites, gold, tellurides of 

 gold, &c. There are no grounds for believing that the mines of 

 Kalgoorlie have reached the limit of ore deposition, or that the 

 lodes will not prove productive in depth. Reports on other 



