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PHILOSOPHICAL 
TRANS ACTIONS. 
L A Second Paper on Hygrometry . 
% J. A, De Luc, jE/^, K i?. $* 
Read December 9, 1790. 
I N a Paper which I had the honour to prefent to the Royal 
Society in the year 1773, I iketched the following propo- 
rtions, as fundamental for the conftrudtion of an hygrometer * 
ift 5 That fire, confidered as the caufe of heat , was the only 
agent by which abfolute drynefs could be immediately produced 
(§ 5.). 2d, That water, in its liquid ftate, was the only fure 
immediate means of producing extreme moijlure in hygrofcopic 
bodies (§ 8, and feql). 3d, That there was no reafon, d priori, 
to expedt, from any hygrofcopic fubftance, that the meafurabie 
< Vol. LXXXL B effe&s 
