204 



High-Pressure Electric Accumulator, 





(T)\ 



(r^ 





^ 









H 



5^v 



] 



A 











, 



* 



■V 



J 









4 1 

 c 



viy 



this has been at work (i. e. has been charged and discharged 

 as an accumulator) for eighteen months, 

 is shown in the cut. A is a strong lead 

 vessel, well lined with rubber varnish, 

 to prevent any solution of the lead being 

 formed. 0, H, are platinized platinum 

 cylinders, in inverted tubes held in 

 their proper position by pieces of rub- 

 ber. M is a manometer. The terminals 

 B, C are brought through insulating 

 stoppers. A 10-per-cent. mixture of sul- 

 phuric acid and water is used as the 

 liquid. With this arrangment a pressure 

 of seven atmospheres can be easily used; and thus the tubes, 

 one of which has twice the capacity of the other, can contain 

 64 times the gas that they would do at the usual pressure, A 

 second form has been made by Messrs. Becker Co., for the 

 author. In this a U-shaped glass tube is used, the manometer 

 being attached to the bend, and the sheets of platinum being 

 fused into each leg. This form, although well suited for lecture- 

 purposes, will bear but a small pressure. A curious point 

 observed, and one that is now being carefully worked out, is 

 that the E.M.F. appears to vary much with the pressure. 



The author has, in addition to the experiment described, 

 charged small Faure or lead secondary batteries under pres- 

 sure, the result being that the life of the battery is length- 

 ened by being charged under pressure. Sufficient data 

 have not as yet been collected concerning the variation 

 of the E.M.F. under pressure, and the behaviour of the lead 

 battery under pressure, to put into print. Should others 

 experimentalize in the direction of high -pressure accumu- 

 lators, a caution must be added with regard to the air-space 

 left in the lead chamber: that quantity of air must be left 

 which may be compressed, say, to seven atmospheres of pres- 

 sure before the gas in rises outside. 



Oxygen produced by electrolytic action almost instantly 

 acts on the best India-rubber tubing or varnish, causing splits 

 and cracks to be formed in it. The chambers are now made 

 of lead to which a harder metal has been added. 



Taunton, Feb. 15, 1883. 



