112 



NA TURE 



[June 2, 1898 



that among the Hopi Indians there are priests sl<illed in the 

 lore of the sun, who determine, by observation of the points on 

 the horizon where the sun rises or sets, the time of the year 

 proper for their religious observances. An important ceremony 

 is performed at the winter solstice, and in December 1897 Dr. 

 Fewkes made a special journey to Arizona to study the ritual on 

 the spot. This is not the place to refer to the ethnological aspects 

 of the ceremonials witnessed by him, but the following extract 

 from the Report of the U.S. Bureau of Ethnology will interest 

 students of primitive astronomy. 



" We are justified in accepting the theory that sun and moon 

 worship is usual among primitive men. Whether that of the 

 sun or of our satellite was the earlier, it is not in the province 

 of this article to discuss, but it is doubtless true that sun worship 

 is a very ancient cult among most primitive peoples. The 

 Pueblos are not exceptions, and while we cannot say that their 

 adoration is limited to the sun, it forms an essential element of 

 their ritual, while their anhydrous environment has led them 

 into a rain-cloud worship and other complexities. I think we 

 can safely say, however, that the germ of their astronomy 

 sprang from observations of the sun ; and while yet in a most 

 primitive condition they noticed the fact that this celestial body 

 did not always rise or set at the same points on the horizon. 

 The connection between these facts and 'the seasons of the year 

 must have been noted early in their history and have led to 

 orientation, which plays such an important part in all their 

 rituals. Thus the approach of the sun to a more vertical position 

 in the sky in summer and its recession in winter led to the 

 association of time when the earth yielded them their crops with 

 its approach, and the time when the earth was barren with its 

 recession. These epochs were noticed, however, not by the 

 position of the sun at midday, but at risings and settings, or the 

 horizon points. The two great epochs, summer and winter, 

 were, it is believed, connected with solstitial amplitudes, and the 

 equinoctial, horizontal points, unconnected with important 

 times to agriculturists, were not considered as of much worth. 

 There is every evidence, however, that the time of day was early 

 indicated by the altitude of the sun, although the connection of 

 the altitude at midday with the time of year was subordinated 

 to observations on the horizon." 



Stellar Radiations.— Referring again to the problem of 

 the measurement of stellar radiations, mentioned in our issue 

 of May 12 (p. 39), the recent improvement in galvanometers 

 ought to help the matter towards solution. At the meeting 

 of the Physical Society on May 13, Prof. Ayrton said that 

 the sensitiveness of these instruments had increased during 

 the last few years in the ratio of 27 to 3,310,000. Of 

 course it must be remembered that these figures apply to a 

 particular class of instrument, and that they are based upon 

 a somewhat empirical definition of the factor of sensitiveness. 

 Nevertheless, they do indicate advance in the refinements of 

 current-measurement. 



It is to be hoped that similar attention may now be given to 

 perfecting an electrometer for extremely small potential-differ- 

 ences ; such an instrument is required for the development of 

 photo-electricity generally. The sensitive plates of the cells 

 used by Prof. Minchin for stellar measurement are only a few 

 square millimetres in area ; the advantage of this is that several 

 of them can be placed together at the focus of a telescope. 

 Their function is, not to give current, but potential differences 

 when exposed to light. They respond chiefly to yellow radiations, 

 and each plate, irrespective of its size, gives from one-third to 

 one-half a volt, for daylight. If electrometers could be im- 

 proved in the ratio 27 to 3,310,000, the experiments made by 

 Pouillet, just fifty years ago, might be extended almost to the 

 circumjovial planets. 



The late Prof. Souillart. — At the meeting of the Paris 

 Academy of Sciences on May 23, M. Callandreau gave a short 

 account of the late Prof. Souillart, whose death we have already 

 announced. Prof. Souillart was elected a Correspondant of the 

 Academy in succession to M. Gylden, the Academy thus show- 

 ing its esteem for the astronomer who during thirty years 

 devoted his leisure to the study of the theory of the satellites of 

 Jupiter, and succeeded in bringing out important complements 

 of the chief work of Laplace. It was while studying under M. 

 Puiseux, at the Normal School, that M. Souillart had his in- 

 clination turned to celestial mechanics. In 1865 his " Essai sur 

 la theorie analytique des satellites de Jupiter " appeared in the 

 Annals of the School, and formed the basis of two later memoirs 



NO. 1492, VOL. 58 



— one, published by the Royal Astronomical. Society, devoted to 

 the analytical theory of the movements of the satellites ; while 

 the other, dealing with the reduction of the formulae to numbers, 

 appeared in the thirtieth volume of the " Memoires des Savants 

 etrangers." In addition to these publications, a series of notes 

 appeared in the tenth, eleventh, and twelfth volumes of the 

 Bulletin astronomiqtie. The whole of these works formed the 

 basis of the treatment of the satellites of Jupiter given by M, 

 Tisserand in his "Traite de Mecanique celeste." 



When M. Souillart left the Normal School he was appointed 

 professor of mathematics in the Saint-Omer High School, and 

 at the same time was attached to the Faculty of Sciences at 

 Nancy. In 1873 ^e became professor of mecanique rationelle at 

 Lille University, and, some years later, professor of astronomy, 

 which post he occupied at the time of his death. 



THE INDUSTRIAL APPLICATIONS OF 

 ELECTRO-CHEMISTR V. 



T^HAT electricity is able to bring about chemical change 

 -*■ appears to have been observed for the first time about the 

 middle of last century. With Volta's discovery of the principle 

 of his pile, in 1792, it became possible to set larger quantities 

 of electricity in motion, and in 1800, the year in which Volta 

 described his first large battery, the study of the chemical effects 

 of the electric current may be said to have commenced with the 

 observations of Nicholson and Carlisle on the electrolysis of 

 water. They were the first to notice the separate evolution of 

 the products of the decomposition at opposite poles ; so that our 

 knowledge of electrolysis, upon which the majority of the appli- 

 cations of electro-chemistry depend, may be said to have been 

 acquired in the nineteenth century. 



In the early 'thirties it was repeatedly proposed to deposit 

 metals by immersing the object to be coated in a solution of the 

 metal, placing it in contact with a more oxidisable metal. An 

 external source of current was applied to electrotyping in 1839 

 by Jakobi, Spencer and Jordan independently of each other ; 

 the first-named also describes the employment of electrolytic 

 gas in producing lime-light. The use of a current generated by 

 magneto-electric machines was patented in 1842, and, according 

 to Mr. Swan, current generated in this way was employed by 

 Messrs. Elkington at Birmingham in that year. It was not, how- 

 ever, until 1864-5 that the more perfect machines of Pacinotti and 

 Wilde made it possible to produce the electric current at a 

 sufficiently economical rate to permit of its employment in a 

 chemical process on the manufacturing scale. The electrolytic 

 refining of copper was patented by Mr. J. Elkington in 1865 

 and 1869, and in the latter year the first electrolytic copper re- 

 finery was erected at Pembrey, near Swansea. The progress of 

 electro-chemical industry was at first slow, but the improvements 

 in dynamos and steam-engines, stimulated by the rapid exten- 

 sion of the applications of electricity to lighting and other pur- 

 poses, the development of water powers, and last, but not least, 

 the impetus given to the study of electro-chemistry by the 

 theories of Van 't Hoff and Arrhenius, have contributed to make 

 this progress during the past decade extraordinarily rapid. 

 A circumstance, the effect of which on the future development of 

 the applications of electro-chemistry is not to be underrated, is 

 the evolution of a new type of chemist — one, namely, who adds 

 to his knowledge of chemistry a competent knowledge of physics 

 and especially of electricity ; there can be no doubt that the 

 country in which the facilities for obtaining training of this kind 

 are defective will be heavily handicapped in the future. With 

 special electro-chemical laboratories being founded at almost 

 every university and polytechnic in Germany, it is depressing 

 to see so little being done in our own country (more especially 

 since it is apparently becoming increasingly difficult for foreigners 

 to obtain admission to the German laboratories). 



The present position of technical electro-chemistry has not 

 been attained without many failures ; instructive and interesting 

 as many of these are, it is impossible to refer to them within the 

 limits of this article, which must, therefore be confined to a 

 general description of processes actually employed. 



The oldest and most important of these is the electrolytic 

 copper-refining process. The copper containing 0*3 to 2 per 

 cent., or sometimes more, impurity is cast into plates which 

 are suspended, some 3 or 4 inches apart, in large, lead-lined 

 wooden boxes. Between each pair of plates a thin sheet of pure 

 copper is suspended, and the solution, containing 15 to 20 per 



