On certain Electrical Pheenomena. 287 
gether, and then complains that in my “ limited survey’’ I did 
not. notice the objections of both; when he knows that in his 
“ Reflections” he stated only his own objections but none of 
theirs, and consequently J had only the former to notice, ‘ The 
experiments are of a delicate kind, and [ stated that they only 
‘succeed in certain states of the weather. The period when 
I made them was dry sunny weather, and I] have never found 
them to succeed easily but in the middle of summer.” Mr. Do- 
novan in the above sentences has endeavoured to define the 
state of the weather in which his delicate experiments will 
succeed; but unfortunately he has not accomplished his inten- 
tion. ‘The period when he made them, he says, was div and 
sunny.’ Now we may have dry and sunny weather in spring, 
summer, autumn, and winter; and consequently it might have 
been inferred that in such a case the experiments might be 
made in either of these seasons: but this inference seems to be 
doubtful; for he immediately adds, ‘‘ I have never found therm 
to sueceed easily but in the middle of summer.” Here, though 
the time or season of the year is determined, the state of the 
weather is left undetermined; for the middle of summer is not 
always dry and sunny, but is sometimes dry and cloudy, and 
sometimes wet and cloudy. This uncertainty with respect to 
the weather seems to have prevented Mr. Donovan from re- 
‘peating his experiments; but when he receives the intelligence 
that they may with a litile care be successfully performed in 
every stale of the weather, on any day in the year, and at any 
hour. of the day, he will doubtless be much gratified to find 
that he needs not wait till midsummer to ascertain the fallacy of 
his own, or the correctness of mine. “ It is very difficult to 
determine what body is positive or what negative; for positive 
bodies will, under certain circumstances, attract positive bodies, 
and negative bodies will attract negative.” 1 deny that it is 
very difficult to determine what body is positive or what negative, 
for in most cases it is extremely easy to determiite it; and if 
Mr. Donovan has really experienced any difficulty in such cases, 
he has experienced it where no other electrician has experienced 
any. If He alludes particularly to the experiments in dispute, 
[ still deny the fact ; for there are several methods by which the 
electrical states of the phial may be ascertained with ease and 
certainty. The reason that he assigns for the above difficulty is, 
that ‘* positive bodies will, under certain circumstances, attract 
positive bodies; and negative bodies will attract negative.” Let 
this be granted, and I ask, will positive bodies repel negative 
Lodies, or negative bodies repe! positive bodies, under any cir- 
cumstances whatever? Tor, if they will not, this difficulty of 
Mr. Donovan’s must vanish in a moment. The electrometer 
of 
