j 2 Mr. de Luc on 
In thofe experiments a Angular phenomenon happened in both 
liygrofcopes. The firft effeCt of the immerfion of thofe animal 
fubftances in alcohol (and I fuppofe it would have been the fame 
with vegetable ones) was contraction , foon followed by expanfon\ 
and when they came out into the air, the firft effe<ft was expanfion , 
foon followed by contraction . The caufe of that reciprocal phe- 
nomenon is undoubtedly the affinity of alcohol with water. In 
the immerfion, fome of the moifiure came out of the fubftance, to 
unite with the furrounding alcohol ; by which lofs of water , a con~ 
fraction took place in the fubftance, ’till it came to imbibe the 
alcohol itfelf. In the immerfion, fome of the moijture of the 
air, uniting immediately with the alcohol retained by the fub- 
fhnce, expanded it to the fame degree as if it had been in water ; 
after which, the alcohol evaporating, the fubftance contracted. 
Thofe phenomena did not happen with ether \ this not uniting 
readily with water ; but it expanded thofe fubftances as much 
as alcohol , and nearly as much as water. From thofe pheno- 
mena we may conclude, that the penetration of animal fub« 
fiances by water , and confequently by moijlure , is produced, as 
that of fugar, fund f one , and every other porous fubftance, by 
the faculty of capillary pores , without any affinity between them 
and water , 
i 8. 3 d. Exp. In that theory, of a mere imbibition of water 
by hygrofcopic fubftances of the elajlic kind, a circumftance, 
which feems to point out affinity , was to be explained ; it is that 
of the hygrofcopic equilibrium. In view of that objeCl, I made 
the following experiments, not newin themfelves, but direftedto 
my purpofe. I took fome glafs tubes, of different fmall bores, 
which I firft bent in the fhape of fyphons ; after which I cut 
them in the middle of the bent part. This was to enable me, 
to bring ihto exaCt communication the lower end of two tubes, 
though* 
