Dec. 1 8, 1879] 



NATURE 



151 



during twenty years, ar.d with many of which the readers 

 of NATURE have been made familiar from time to time. 



The basis of these experimental researches is the 

 secondary battery, originally devised by Ritter, but which 

 in M. Planters hands has become developed into what is 

 practically a new and important source of electricity. M. 

 Plante", by employing for his secondary cells large plates 

 of lead immersed in dilute sulphuric acid, charged by a 

 small Bunsen's or Grove's battery, and by arranging the 

 secondary cells in such a manner that they can be charged 

 in multiple arc, and discharged in series, obtains during 

 the ten minutes or so during which the discharge continues 

 currents not only of as great electromotive force as would 

 be obtained from a Grove's battery of a much larger 

 number of cells, but also of much greater " quantity ; " 

 the internal resistance of these secondary cells being 

 excessively small. 



In studying the construction and operation of these 

 secondary batteries, M. Plante" has brought to light a 

 large number of interesting facts. He finds that such 

 batteries improve with use, the two lead electrodes gradu- 

 ally becoming spongy, thereby holding in loose combina- 

 tion larger quantities of the oxygen and hydrogen gases, 

 respectively, than new plates of lead. He observes several 

 highly suggestive analogies between this electro-chemical 

 accumulation of the energy of the current, and the electro- 

 static accumulation of the Leyden jar. This analogy ex- 

 tends even to the existence of a residual charge. It appears 

 that the electromotive force of such a cell well charged 

 may be as high as 27187 volts, while the internal resist- 

 ance may be as low as 0*05 ohm, and that the actual 

 quantity of the primary current which may be realised 

 after being thus accumulated amounts to 88 per cent. 

 These data are given amongst the stores of information 

 in the first section of M. Plante" s work. The second 

 section treats of the practical uses which have been made 

 by M. Trouve" and others of the currents from secondary 

 batteries, and which embrace a wide range of applica- 

 tions, chief amongst which is the application to surgical 

 cautery by means of wires raised to a white heat, for 

 which operation a powerful current of short duration only 

 is required. Another suggestion, to employ such batteries 

 as accumulators of the current supplying electric lights 

 has already been seized upon by more than one inventor 

 amongst others by Mr. Edison. 



The third section of the work before us deals with 

 sundry phenomena produced by the discharge of the 

 powerlul currents of large secondary batteries. To obtain 

 these effects M. Plante - has used batteries of from 2co to 

 Soo secondary elements. Luminous liquid globules and 

 delicate fl.ime-like aureoles are produced at the surface of 

 liquids » hen the current is led into them under certain 

 conditions : even a globule of fused mica has been pro- 

 duced by the current, and wandered about in a manner 

 suggestive of the alleged behaviour of the " balls of fire" 

 sometimes accompanying violent thunderstorms. The 

 disclnrge may even be employed to write upon glass 

 which is etched away under the negative pole of the 

 secondary battery. The many analogies presented by 

 these experiments with some of the less understood of 

 natural phenomena, globular lightning, auroras, and 

 wreathed lightning discharges, &c, are treated in detail 

 in the fourth section. M. Plante considers the " Fire of 



Saint Elmo" to be a phenomenon of discharge of nega- 

 tive electricity, whilst he compares the globular lightning 

 to the phenomena observed in the discharges at the posi- 

 tive pole of his batteries. One of the most curious of his 

 speculations is that concerning the spiral nebulae, which 

 he compares with the spiral forms produced at the nega- 

 tive pole when dilute acid is electrolysed by a moderately 

 strong current between copper electrodes in the presence 

 of a powerful electromagnet. These " electrodynamic " 

 spirals consist of streams of particles of oxide of copper 

 whirled off from the end of the electrode and which, con- 

 ducting the current, undergo a rotatory displacement 

 under the influence of the neighbouring magnet. These 

 spirals, which therefore indicate the lines of flow of the 

 current, resemble the spirals obtained by the present 

 writer in iron filings under the joint influence of a magnet 

 and a current traversing it longitudinally, and which 

 differed from those of M. Plante" in indicating lines of 

 magnetic induction, not lines of current flow. So strongly 

 does the analogy of form weigh with M. Plante" that he 

 asks (p. 243) whether the nucleus of a spiral nebula is not 

 truly an "electric focus," and "whether the spiral form 

 is not probably determined by the presence in the neigh- 

 bourhood of strongly magnetised heavenly bodies!" 

 Another astronomical analogy is discovered by the author 

 between the sun-spots and certain " crateriform perfora- 

 tions " which are produced in moistened paper beneath 

 the positive pole of the secondary battery. 



The fifth, and last part of the work, explains the con- 

 struction and operation of the author's " rheostatic 

 machine," which is a series of mica condensers which 

 are charged in multiple arc from a battery of 600 or 800 

 secondary elements, and discharged in series in very 

 rapid succession. This instrument is capable of pro- 

 ducing almost continuously the effects of intense dis- 

 charges of statical electricity, and promises to prove of 

 great utility as an instrument of research. 



We have preferred to give the reader a brief n'sume of 

 the contents of this delightful narrative of researches, 

 rather than to criticise in detail the many salient points 

 which it presents. Experimental researches of the present 

 day are seldom conducted with such patient and ingenious 

 endeavour as those now published in M. Plante" s volume. 

 The student of electrical theory will find in them but little 

 that he did not know before. The phenomenal not the 

 theoretical aspect of the question is ever uppermost ; and 

 in default of theory there is a tendency to ride the analogies 

 too hard. But none can help admiring the beauty and 

 originality of the experiments here recorded, nor doubt 

 the very high value of the results obtained. There will, 

 too, be many readers who will long that all treatises on 

 experimental science were written in so clear, concise, 

 and elegant a style as that of the author. 



Silvanus P. Thompson 



NATURAL HISTORY OF THE ANCIENTS 

 Cleanings from the Natural History 0/ the Ancients. By 

 the Rev. W. Houghton, M.A., F.L.S. Illustrated. 

 (London : Cassell, Petter, and Galpin, 1880.) 



THIS interesting volume consists of a series of short 

 lectures treating of most of the animals known to 

 the early inhabitants of Egypt, Palestine, Assyria, Greece, 



