On the Compressibility of Water. 347 
The answer is obvious. Let every man fuagnish his barn, 
as well as his house, with a lightning rod. In the case of 
such low buildings, a rod, which, without a curvature, may 
pass up at one end, would cause but a trifling expense, and, it 
is believed, would, in most cases, prove a perfect security. 
When the barn is very long, it may be better to let the rod 
pass over the middle of the roof, or else to have two rods— 
one at each end of the building. 
Art. XVI.—On the Com essibilty of Water ; by Jacon 
ae from the P Philoso, heal Transactions of 
n wd Ban ihe sD June 29, 1820, 
pee ee to the editor Ses Journal, by the author. 
(With Notes, by a Gacteiiaaans: 
‘Havine believed, for many years, that water was an elas- 
tic fluid, [ was induced to make some experiments, to ascer- 
tain the fact. (a) This was done by constructing an instru- 
(a) Although the seria ents detailed i in this paper atargae a tps cole of 
beats 
the compressibility of w ¢ 
they. cannot, be: regarded. at as the first hei? 
a : 
off the Lealed eu of the tube of a water or oil thermometer, and admitting 
the pressure of the air upon the column of the fluid, it instantly sunk. But, 
ca! it to the ——— of the fluid, he resorts for an 
mi whit 
