114 New Secondary Cell for Electrical Storage. 



reduced, the copper element becoming oxidised ; the oxide 

 combines with the acid, and forms cupric sulphate, the 

 solution returning to its original azure blue colour. This 

 change in colour forms a beautiful means of knowing when 

 the cell is fully charged. The power of this cell is very 

 great and constant ; it can be made to last for hours, the 

 length of time being dependent on the quantity of cupric 

 sulphate being decomposed in solution. I have, by the 

 decomposition of one pint of solution cupric sulphate, 

 obtained over two hours' effective work as electric energy. 



It will be seen from the foregoing that this method of 

 conserving energy has a wide field before it. 



Note 1. — The amalgamated lead electrode will not 

 per oxidise if free cupric sulphate crystals are present in 

 the solution, it being essential that the solution become 

 acid. 



Note 2. — The charging is accompanied with a peculiar 

 rattling noise, and is not due to escaping gas, as the noise 

 occurs when no gas escapes from the solution, but may be 

 due to change of form in spiral due to deposition of copper. 



ADDENDUM. 



The secondary, in its present form, consists of a flat copper 

 case, having the form of the outer containing vessel of a 

 Grove's cell. In this copper cell is a sheet of lead amalga- 

 mated with mercury, and which has a piece of flannel, or 

 other porous material, enveloping it tightly, the object of 

 which is to prevent the peroxide (which forms a thick 

 layer) from falling off by the wash of the solution, or by 

 jarring. I have removed as much as six ounces of peroxide, 

 which has been formed in a single charge in one of my 

 cells. 



The amalgamated plate is supported in middle of copper 

 cell by being held in a groove in a piece of parrafined wood 

 lying at the bottom of copper cell, and also by a parrafined 

 wood cap, which closes the top ; it is charged with a solution 

 of cupric sulphate, containing one-twelfth of hydfic sul- 

 phate. 



The amalgamated lead is made the positive electrode, and 

 the copper case the negative, the inner surface of the 

 copper case receiving the deposited copper when charging 

 with electricity. The electromotive force of the cell is 

 about two volts. 



