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3. Note on the Electricity developed during Evaporation 
and during Effervescence from Chemical Action. By 
Professor Tait and J. A. Wanklyn, Esq. 
One of Professor W. Thomson’s Divided-Ring Electrometers 
having been recently procured for the Natural Philosophy collection 
in the University, we have made use of it in repeating and extend- 
ing the experiments of Volta, Pouillet, and others, on the elec- 
tricity produced during the evaporation of various bodies. In some 
cases our results agree with those already known, but in others we 
find effects differing totally in kind or degree from the accepted 
ones ; and with some substances we find occasionally contradictory 
indications among our own results. 
The Electrometer is in every respect a far superior instrument to 
the gold-leaf electroscope, which (sometimes with the addition of a 
condenser) was used by former experimenters, and enables us to give 
our results in a form easily reducible to absolute measure. The 
charge of the instrument was such that, when the half rings were 
respectively connected with the zinc and platinum of a single 
Grove’s cell, the deflection observed amounted to about 5*8 scale 
divisions. This was found to be the most useful charge for the bulk 
of our experiments, but it was easily increased twenty or thirty fold 
when we sought to verify any very delicate indications. 
Our apparatus consisted of a platinum dish, placed on an in- 
sulating stand, and connected with the insulated half ring. A 
lamp could be placed on the stand so as to heat the dish; and while 
this was going on the indications of the electrometer gave us the 
atmospheric charge. The experiments were all conducted when the 
latter was very small, so that although the sputtering of the fluids 
dropped on the hot plate may have prevented us from observing some 
slight effects, the large deflections we observed in many instances can 
have nothing to do with the electric state of the air of the room. 
With a different disposition, which enabled us to use a Bunsen lamp 
to heat the dish, we obtained the atmospheric potential by burning 
a little ether or alcohol on the dish itself, when the lamp was 
removed. 
We agree generally with previous experimenters, that during the 
continuance of the spheroidal state, there is little, if any, perceptible 
