545 
disengagement of electricity. We also agree with the statement 
that the main effect is produced while the fizzing sound that accom- 
panies the loss of the spheroidal state is heard, and that during the 
continuance of the mechanical action to which that sound is due, the 
indications of the electrometer in general steadily increase. That 
the greater part of the electricity produced is due to friction is proved 
by the fact that, when fluids are forcibly squirted upon the hot dish, 
the electrical indications are very much increased, and that a con- 
cave surface gives far more powerful deflections than a convex one 
at the same temperature. The sputtering or violent boiling which 
succeeds the fizzing state, shows little, if any, disengagement of 
electricity. The principal interest of the results which we have 
obtained is in the cases of iodine, bromine, and various other 
bodies which do not seem to have been before examined. We have 
as yet met with no discordance in our own results as far as simple 
bodies are concerned. 
In giving the following numbers, we have not attempted any cor- 
rection for the loss of electricity which is caused by the high tem- 
perature of the platinum dish. 
Mean Electric Effects given by a few substances during the continuance 
of the fizzing sound which immediately folloivs the disappearance 
of the Spheroidal State, 5'8 representing the Electromotive Force 
of a Single Grove’s Element . 
Bromine, 
Iodine, .... 
Bromide of Ethyl, . 
Iodide of Methyl, . . | 
Benzole, 
Valerianic Ether, . 
Common Ether, 
Chloroform, . 
Ammonia, 
Alcohol, 
Mercury, 
Chloride of Sulphur, 
Water (distilled), containing' 
only a trace of carbonic 
acid, which was too small 
to be detected by lime- 
water, . . . 
* This sample was in fine crystals, 
obtained from it in powder. 
+ 400 
+ 90 * 
+ but very small indeed, if any 
In many experiments strong -f , but 
in three cases pretty strong — 
No effect 
No effect 
Very slight and dubious effects 
— if plate very hot, q- if colder 
- 200 
- 10 
- 75 
- 100 
Far higher effects (also positive) were 
