ANOMALOUS ELECTRO-CHEMICAL EFFECTS. 389 



In this experiment the liquid was exposed for twenty-four 

 hours, during ten of which the discharges were kept up, while 

 in the previous experiments less than an hour was sufficient, 

 and the water had not cooled from its preliminary boiling 

 before the experiment was completed. 



6th. I next tried a strong solution of sulphuric acid, specific 

 gravity 1*23 ; the gas from the coated point, which was positive, 

 contracted to O'2 of its volume ; the residue was hydrogen. 



7th. I used a still stronger solution, specific gravity 1*45, 

 both points being coated ; the volume from the negative pole 

 was to that from the positive as 4*5 to 3*25 ; the gas from the 

 negative pole contracted in the eudiometer to only 0*95 of its 

 volume ; the residue was pure oxygen ; the gas from the posi- 

 tive pole contracted to 0-5 ; the residue was hydrogen. Here, 

 to my surprise, there was, after the first contraction, a resi- 

 duum of oxygen in the ratio of more than 2 volumes to I of 

 the residuum of hydrogen. The experiment was repeated 

 with acid of specific gravity 1*5 ; from the positive point 3*3 

 volumes were collected, from the negative 2*6 ; the gas from 

 the negative pole contracted to 0*9 of its volume ; the resi- 

 duum was pure oxygen ; that from the positive contracted to 

 0*4 of its volume, the residue being hydrogen. 



8th. I now tried a saturated solution of sulphate of cop- 

 per with a few drops of sulphuric acid added ; a remarkable 

 difference was shown in the conducting power of this solution 

 as compared with the dilute acid ; the contact-breaker of the 

 primary coil gave very minute sparks, unattended with the 

 usual snapping noise ; it was much as if the terminals of the 

 secondary coil had been united by a metallic connection ; and 

 the superiority of the conducting power of the solution of sul- 

 phate of copper in this experiment over dilute sulphuric acid 

 was far greater than is shown in ordinary electrolysis by the 

 voltaic battery. The coated point was positive, the plate nega- 

 tive ; the gas from the positive point detonated, leaving a 

 very slight residue ; but on the interior of the collecting tube, 

 near the point, was a deposit of pulverulent metallic copper. 

 On the negative plate there was no deposit, and no gas was 

 given off from it. Here the copper deposit was evidently 

 a reduction occasioned by the excess of hydrogen, but there 



