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XXI. Intelligence and Miscellaneous Articles, 



ON SECONDARY CURRENTS AND THEIR APPLICATIONS. 

 BY M. G. PLANTE. 



/^BSERVATIONS of the intensity of the secondary current deve- 

 ^-' loped in a voltameter with lead electrodes induced me, in 1860, 

 to construct a pile or secondary battery by which, within certain 

 limits, the work of the voltaic battery could be accumulated*. I 

 have now to describe a new mode of arranging the apparatus, as 

 well as the effects of quantity and of tension which can be obtained by 

 its means. 



The instrument, which I designate secondary quantity battery, con- 

 sists of a rectangular gutta-percha vessel provided with a number of 

 lateral grooves very close to each other, and containing a number of 

 lead plates immersed in water acidulated by sulphuric acid. The 

 odd-numbered plates are all joined, and may be connected with one 

 of the poles of a battery ; the even plates are also joined, and may be 

 connected with the other pole, so that all the plates form one single 

 secondary element of large surface. 



When, on such an apparatus constructed with six lead plates 

 20 centims. square, the current of two small nitric-acid couples is 

 allowed to act, and when the circuit is broken by means of the com- 

 mutator so as to close the secondary one, temporary incandescence 

 is obtained of a platinum wire 1 millim. in thickness and 8 centims. 

 in length — a result which would otherwise be impossible with the 

 feeble source which furnishes the principal current. 



To obtain more powerful effects, I have constructed batteries of from 

 twenty to forty lead plates united together ; these batteries produce 

 very intense calorific effects, such as the fusion of iron or steel rods, 

 when they have been charged by two or three Bunsen's elements 

 from 15 to 20 centims. in height. 



In the production of many of the effects of voltaic electri- 

 city, the quantity of electricity furnished by the current would be 

 insufficient if it were not associated with a certain tension. M. 

 Thomsen of Copenhagen described, in 1865, a polarization battery 

 based on the current produced by platinized platinum electrodes, and 

 by means of which he obtained a series of secondary currents suffi- 

 ciently close to form a continuous series having higher tension than 

 the principal one. 



I thought that the intense current furnished by lead electrodes 

 might be used for producing temporary effects of great tension, and 

 I have attained this object by arranging the secondary couples so 

 that they could be charged simultaneously in quantity and then dis- 

 charged in tension. 



The secondary tension battery which I have constructed consists of 

 forty secondary couples, each formed of a very narrow gutta-percha 

 vessel containing two lead plates, 20 by 20, immersed in dilute acid. 

 The poles of all the couples contained in the same box terminate in 

 a commutator so constructed that it can join them either in surface 

 or in tension. 



If this battery be charged by the aid of three Bunsen's elements 

 * Phil. Mag. S. 4. vol. xix. p. 468. 



