Sir Benjamin Thompson’s Experiments, &c. 85 
ments, I flatter myfelf that you will not think an account of 
my labours upon this fubjedt altogether uninterefting. 
Before I enter upon the detail of my experiments it will be 
neceflary to premile, that I fhall in general confine myfelf 
merely to the fadts as they appear, without applying them to 
the confirmation or refutation of the theories of others, and 
• * 
without entering into any fpeculative enquiries relative to their 
remote caules ; and in defcribing the different appearances 1 
fhall make ufe of the moll familiar terms. Thus, in fpeaking 
ot the air produced upon expofing raw filk in water to the adtion 
ot light, I fhall fometimes mention it as being yielded by the 
filk ; and 1 fhall fometimes fpeak of the air furni filed by ex- 
pofing water, which has previoufly turned green, in the fun’s 
rays, as being immediately produced by the water, though it is 
probable, that the green matter acts a very important part in 
the produdfion of this air in the one cafe and in the other. But 
how it adts is not well afcertained ; and I had in general much 
rather confine myfelf to a fimple, and even an unlearned, de- 
fcription of fadts, than by endeavouring to give more precife 
definitions, at firff, to involve myfelf in all the difficulties 
which would attend accounting for phenomena, whofe caufes 
are but very imperfectly known. 
You will, therefore, not be furprifed, if you fhould fome- 
times find me fpeaking of appearances in the fame manner as 
a perfon would mention them who faw them for the firff time, 
and who did not know that others had dilcovered them before, 
and how they had endeavoured to account for them. I fhall 
take care that the fadts fhall be faithfully defcribed, and I flat- 
ter myfelf you .will not think them the lefs intereffing on 
account of their being unadorned. — But I haften to give you 
an account of my experiments. 
Expt - 
