450 Mr. G. W. Wigner on Grove's Battery. 



in favour of nitrosulphuric acid ; and the results I have obtained 

 are very satisfactory, amounting in one case to a loss of only 18 

 per cent, in the light, ten hours after setting up the batteries, 

 more than six hours of which the batteries were in circuit. 

 If only four or five hours' work is required from the battery, 2 

 lbs. nitric acid (1-860 spec, grav.) to 5 lbs. sulphuric acid (1'845 

 spec, grav.) will be a very good proportion ; but if more work is 

 required, the proportion of nitric acid maybe increased to 3J lbs. 

 I once worked sixty cells very satisfactorily for four hours with 

 only 1 lb. nitric to 5 lbs. sulphuric. 



I do not find that any excessive action on the zinc takes place 

 owing to this change ; and its economy as regards the acid is self- 

 evident. 



The diluted sulphuric acid which I use is generally 1 to 6 by 

 bulk. 



Now a few words as to the mode of filling the cells. 



The old plan of jug and funnel is slow and unsatisfactory ; and 

 I have adopted with great success the siphon principle, as follows. 

 I mix the acids in two large stone bottles fitted with corks 

 having two holes in each. Through one of these holes a glass 

 tube passes to the bottom of the bottle, bent over outside for 

 some two or three inches. Attached to this is a piece of india- 

 rubber tube about 6 feet long, with a jet not more than 3 inches 

 in length at its end. This jet is formed of a piece of glass tubing, 

 slightly flattened in the lamp, for convenience in inserting it into 

 the cells. To regulate and stop the flow of the acid, I use one 

 of Mohr's spring pinchcocks, which clamps the india-rubber tube. 

 The other hole in each cork is for a blowing-tube, passing a very 

 short distance into the bottle, to charge the siphons with. These 

 being once charged, it is very easy to pass the jet from cell to 

 cell (stopping the acid meanwhile by the pinchcock) without 

 spilling a single drop ; and so quickly can this be done, that I 

 have repeatedly charged sixty cells with both acids (without as- 

 sistance) in from 20 to 25 minutes. The bottles, of course, should 

 stand some four feet above the level of the battery. The india- 

 rubber tube should be rinsed out immediately after use, with 

 water containing a little alkali ; it will then last for a very long- 

 time. 



As to the results which I have obtained by these various 

 alterations, it will perhaps be sufficient to give a few measures of 

 the power of the light between charcoal-points reduced to stand- 

 ard sperm candles. They are as follows : — 



Sixty cells as usually constructed and putl -, anr\ -n 

 together gave a light of ..... J 

 Size of platinum 5 x 2J. 



