Mr. H. F. Morley on Grove's Gas-Battery, 275 



For the couple with unjoined plates — 



,. rx i. * -r Volume lost, in 



May8. Oct. 4. Loss. cubic centi ^ 8 . 



Hydrogen 63'9 59*3 4*6 '90 



Oxygen 64-1 61*3 2*8 '44 



For the couple with no plates — 



Hydrogen 92-0 86-9 5*1 1-30 



Oxygen 9(H) 85'4 4'6 -74 



In this case a good deal of gas seems to have been lost by dif- 

 fusion. 



The ratio of hydrogen lost to oxygen lost in the three cases 

 is 4*8, 2*1, and 1*8 respectively. If we assume that 1*8 is the 

 ratio of the gases lost through diffusion, and that the loss of 

 oxygen in the first two cases is due solely to this cause, we 

 shall find that 1*79 and *11 cubic centim. of hydrogen respec- 

 tively still remain to be accounted for in the two cases. I 

 attribute this loss to local currents in the second case, and 

 partly to these but chiefly to the main current in the first 

 case, most of the necessary oxygen being supplied by the air 

 to the liquid. 



IV. If the hydrogen in a gas-couple with submerged plates 

 be warmed by the hand, the current is increased ; and if it be 

 cooled the current is diminished : indeed it is very sensitive 

 to changes of temperature, and of pressure also ; and hence it 

 is hardly possible to determine its strength with much accu- 

 racy. The further any horizontal layer of liquid in the hy- 

 drogen-tube is from the gas, the less hydrogen does it contain. 

 Any expansion of the gas from heat or decrease of pressure 

 brings a more saturated solution into contact with the immersed 

 plate and the current increases, whereas contraction produces 

 the opposite effect. 



Y. When a cell has been recently charged by electrolysis 

 the current is at first very strong ; but it soon falls off, and at 

 last remains of nearly constant strength. This is because the 

 water was at first saturated with the gas, but this gas being- 

 used up by the current takes some time to be restored by so- 

 lution at the surface, and when equilibrium is attained the 

 liquid round the plate will contain less dissolved gas the further 

 it is from the surface. M. Gaugain attributed the falling-off 

 in the strength of the current to the deposition of hydrogen 

 on the positive plate ; there is no need, however, for any such 

 supposition. 1 employed a battery in which the plates were 

 wholly immersed ; and the final current varied with the depth 

 of the top of the plate in the hydrogen-tube from the surface, 

 and with the resistance in circuit, as the following Table 

 shows : — 



T2 



