264 LOCALIZED ELECTRIZATION. 



G. — The Battery. 



From the beginning of my researches and until 1858, I 

 had employed Bunsen's battery in my volta - faradic instru- 

 ments, because it combines with sufficient power a considerable 

 degree of constancy. I modified it only by arranging it in a flat 

 form, so that it could be contained in a drawer. Instead of im- 

 mersing the carbon in nitric acid, I poured the acid over a plate 

 of carbon so as to saturate its pores, and then put this plate into a 

 zinc cell containing a small quantity of solution of sea-salt. My 

 only diaphragm was thus a thin layer of saline solution ; by which 

 arrangement the resistance of the battery was much diminished, 

 and its power proportionately increased. 



Such a battery as this was perfectly in accord with the force of 

 my first instrument. But, since I have fully doubled the original 

 length of the coils and of their wires, it has been insufficient to 

 develop the full power of the apparatus. I have therefore been 

 compelled to seek a battery yielding electricity of higher tension. 

 For this purpose I have diminished by one-half the surface of 

 the elements, and have increased their number to three or even 

 four. 



The inconveniences due to the employment of nitric acid, that is 

 to say, the inevitable liberation of nitrous gas, which was a cause 

 of the rapid deterioration of the several parts of the apparatus, in- 

 duced me to replace the nitric by sulphuric acid. For more than 

 a year I had employed this new arrangement, when M. Marie- 

 Davy made known his battery with bisulphate of mercury, which, 

 with some modifications, I adopted for my instruments. It is to 

 this source of electricity that I have now for six years given the 

 preference for my portable forms of apparatus , and a description 

 of it has already been given to the reader. It possesses the advan- 

 tage that it may be carried from place to place, without fear of 

 spilling any liquid. It is sufficient to place a piece of hard caout- 

 chouc between the cloth and the zinc, carefully cleaned, in the 

 intervals between the applications; and when we wish to put 

 the battery in action, to pour a little water upon the cloth, and to 

 remove the plates of caoutchouc. The same bisulphate of mercury 

 will last from fifteen days to three weeks. 



The pieces connecting the system of induction with the carbon, 

 composed originally of copper, platinized at its contact with the 

 carbon, were rapidly destroyed by oxydation. I have replaced 

 them by platinum wires, and they are now unalterable. The two or 

 three small elements which form a part of my volta-electric appa- 

 ratus, allow me to have, at the bedside of the patient a power of 



