E tee: J 
meafure of nitrous air, fhakes the 
) tube in the moment the two 
airs come: into contaét, and, after 
fome repofe, he moves again the 
o of the brafs fcale to the place 
where the columns of air and water 
meet, and writes down the degree 
of the f{cale which corres ponds with 
the next mark of. the lake tube 
: above the water. Aiter this he lets 
23 a a Sas gmeatare of nitrous air, 
the fcale arent e with rie 
next mark of the glafs tube above 
the water, and thus finifhes the 
whole operation, if the air exa- 
as, common air: for -no 
diminution of this air would 
- ., Dappen” _— more nitrous air was : 
= eae as three meafures. of | ni- 
ug trous air are fufficient to faturate 
3 
