j 2 Mr. kirwan’s Experiments , &c. the fpecific Gravities 
attraction was not very confiderable, yet the following experi- 
ment was more fatis factory . 
I expofed 1440 gr. of this fpirit to marine air for five days, 
the thermometer being at 50° or under; it then weighed 1 562 
gr. and confequently imbibed 122 gr. of marine air; its fpccific 
gravity was then 1,253, which agrees exactly with what it 
fliould be by calculation. 
N. B. I have not repeated the whole of thefe experiments, as 
they were very tedious ; but I began them over again feveral 
times before I could afeertain with any precifion the quantity of 
marine air abforbed, as, when the whole of a cylinder full of 
air was abforbed, it was difficult to flop the bottles fo as to pre- 
vent any mercury from falling in ; and I was obliged every night 
to fill the cylinders with air, left if there remained but a fmall 
quantity it might be imbibed before morning, and the mercury 
fall into the bottles. I alfo made fome allowance for the com- 
mon air which I could not avoid letting into the cylinder with 
the marine air, as will be very apparent to whoever repeats the 
experiment. 
Being now fatisfied I had difeovered the proportion of acid 
and water in fpirit of fait, I was impatient to find it in other 
acids alfo; and for that purpofe I took 180 gr. of very ftrong 
oil of tartar per deliquium , but of whole fpecific gravity I can 
find no note, and found it to be ftiturated by 1 80 gr. of fpirit 
of fait, whofe fpecific gravity was 1,225. Now, by calcula- 
tion it appears, that 180 gr. of this fpirit contains 48,7 gr. of 
acid and 131,3 of water, and hence I drew up the following 
table. 
Marine 
