the weakeji Natural or Artificial Eleclrlcity. xxxi 
The experiment on the evaporation of water, which did not 
anfwer fo well at Paris, lucceeded much better in London, 
where I bethought me of throwing water upon the lighted coals, 
which were kept in an mfulated chafing-difh. In this manner 
the electricity of the evaporation never fails to eieCtrify^ the 
chafing-difh negatively, and ftrongly enough tor the electricity 
to be difcovered by the Ample electrometer; it will even afford 
a fpark, if the condenfer is ufed. The firft experiment u- this 
fort was made at Mr. bennet’s, who is a great lover pf electri- 
city, in prefence of Mr. bennet, Mr. cavallo, and Mr. 
kirwan, members of the Royal Society, and of Mr. walker, 
leCturer of experimental philo fophy. 
Another time this experiment was repeated with luccefs at 
Mr. cavallo’s, in the following manner. A fmall crucible,, 
containing three or four fmall coals lighted, was mfulated 5 
then a fpoonful of water was thrown upon the coals, and im- 
mediately after, an cleCtrometer, which communicated with the 
coals by means of a wire, diverged with negative eleCtncity. 
Thele are the experiments which I have had the opportunity 
to make hitherto ; in relating which I muff not omit to obfeive, 
that although the condenfing apparatus has not been always 
indifpenfably neceffary, Mr. cavallo’s very fenfible electro- 
meter alone having been often lufficient for the puipofe; vet it 
muff be con ft {fed, that it was the condenfing apparatus which 
fuggefted thele experiments* and by the help of which even 
the eleCtric fpark could be obtained. Thele experiments have 
juft opened the way to a vaff field, which deierves much far- 
ther inveffigation. It is natural to fuppofe, that if compaCt 
bodies, when they are rarefied or become an elaffic fluid, re- 
quire an additional quantity of eleCtric fluid, and confequently 
leave thofe bodies, with which they are connected, negatively 
eleCtrified; it muff happen, on the contrary, that when va- 
uours condenfe they muff part with fofne eieCtric fluid, that is, 
muff produce a pofitive eleCtricity. This, however, remains 
to be proved experimentally, and I have already imagined feve- 
ral ways of trying it, which will be put in praftice as foon as I 
fhall have the opportunity. Mean while 1 beg leave to con- 
clude 
