Faure s Secondary Battery. 59 



struction of the battery the effects produced were very 

 similar to those observed in the case of the original Plante 

 secondary element, the effects merely lasting for a very short 

 time. 



Parchment paper, from its toughness, has been found by me 

 to be best adapted for the preparation of secondary elements. 



The oxide of lead should, previous to applying it to the 

 lead plate, be well mixed with the acid. If water simply be 

 used for this purpose the cells are with difficulty charged, 

 and oxygen and Irydrogen gases are given off, the lead oxide 

 being only decomposed on the outer surfaces. 



After a time it was observed that the lead terminal which 

 in charging had been connected with the positive pole of the 

 battery had become brittle, possibly from absorption of 

 oxygen. 



It may be observed that the chemical action going on in 

 the Faure battery is not at present well understood ; but it 

 seems that the first action which takes place consists in the 

 removal of the lower oxide present in the red lead by the 

 action of the sulphuric acid with the formation of lead 

 sulphate. 



In charging the lead plates, which, a,s arranged, may be 

 looked upon as a form of voltameter, the one connected with 

 the positive pole of the primary battery becomes surcharged 

 with oxygen, while in the plate connected with the negative 

 pole hydrogen is absorbed with the formation of water and 

 reduction of the oxide of lead to the metallic state. 



The metallic lead so formed, being in a very porous condi- 

 dition, may then be capable of absorbing large quantities of 

 hydrogen. 



Two Callans cells put on to one cell of the Faure battery 

 cause a considerable disengagement of free hydrogen, whilst 

 apparently no oxygen was eliminated. 



In the case of the same number of Callans used with 

 four secondary cells nothing like so much gas was evolved. 



Unfortunately, up to the present, I have been unable to 

 charge the instrument by means of the dynamic machine, 

 either by using an intensity or a quantity armature.* 



For the use of these machines I am indebted to the kindness 

 of Messrs. Josephs and Danks. 



* Note. — Since the paper was read, we have succeeded in charging the 

 secondary cells by making them part of the circuit of a dynamic machine 

 in the act of producing light. Curiously enough, under these circumstances, 

 the electric light appeared, if anything, better and steadier. 



