54 LOCALIZED ELECTRIZATION. 



paratus iu my rooms, for my bells, chamber telegraph, and electric 

 clock, while other fifteen elements had been at rest for the same 

 period. The latter were nearly as much soiled and enfeebled as 

 the former. 



I shall show hereafter how, by means of an apparatus that I 

 have called the isolator and distributor of the battery currents, 

 I have been able to moderate this rapid exhaustion. The sulphate 

 of mercury battery, however, wastes but little during the intervals 

 of its application, and may, without doubt, be kept in activity a 

 considerable time, as much as six or eight mouths, for certain 

 purposes. The power to preserve a sulphate of mercury battery 

 for so long a time without having to devote to it incessant care, 

 gives it an incontestable superiority over the Daniell's ; and the 

 ao-o-regate of all these advantages induces me to give the pre- 

 ference to the sulphate of mercury, for the application of con- 

 tinuous currents for physiological and therapeutical purposes. 



The description of this battery is not yet to be foun 1 in standard 

 works ; and I will therefore describe here the one that I have had 

 constructed upon the model of that at the Ministry of the Interior. 

 Each element is composed (1) of an exterior glass cylinder (V, fig. 

 13) ; (2) of a cylinder of zinc, Z ; (3) of a porous cylindrical cell, 

 D; and of a piece of carbon, C, placed within it. The external 

 cylinder, eight centimetres high and six in diameter, is one-third 

 full of water, in which is immersed the zinc. This is seven centi- 

 metres high, and is formed into a cylinder four centimetres and a 

 half in diameter. The porous cell, as high as the zinc and three- 

 and-a-half centimetres in diameter, is a third full of paste of 

 protosulphate of mercury,^ in which is placed a piece of carbon 

 twelve centimetres high, two-and-a-half wide, and twelve milli- 

 metres in thickness. A plate of copper, riveted and soldered at 

 one extremity to the zinc of one element, is placed in communica- 

 tion wdth the carbon of the next. It is unnecessary to say that a 

 battery formed of forty of such elements is put together like all 

 other i3atteries for obtaining physiological efiects. The details are 

 given in elementary treatises on physics. Many inconveniences 

 have led me to doubt the excellence of this battery. The plates 

 of copper oxidize rapidly at their points of contact with the 

 carbon ; and break on account of their amalgamation with 

 the mercury. I have obviated these inconveniences by giving the 

 pieces of carbon such a height that the acid mercurial solution 



9 To make the paste, a sufficient quan- ! it into a paste. The preparation should 

 tity of water should be poured upon ' be made at the time of setting up the 

 enough powdered proto-sulphate of mer- pile, 

 oury for all the elements, and mixed with 



