the compressibility of water. 327 
compress it half its size, but to separate the neck from the 
body of the bottle. 
Experiment 4. An empty porter bottle, the strongest that 
could be found, was stopped in the following manner. A 
cork with a large head was firmly driven into the neck ; it 
was then covered with six layers of fine linen, saturated with 
a composition of tar and wax ; over them was applied a 
covering of leather, and all perfectly secured by being well 
bound at the neck. The bottle thus prepared was sunk two 
hundred and seventy fathoms. When drawn in, it was 
found perfectly sound, and the sealing unchanged ; but filled 
with water to within an inch of the cork. The coverings 
were taken off, layer after layer, but no signs of moisture 
were visible. Had the bottle remained down a sufficient 
length of time to have completely filled, it would undoubtedly 
have been broken by the expansion of the water upon being 
drawn towards the surface, as was the case in the former ex- 
periment. It is worthy of remark, that when the water from 
this bottle was poured into a tumbler, it effervesced like mi- 
neral water. 
Experiment 5. In this experiment two strong bottles were 
sunk to the depth of five hundred fathoms. One of them 
was stopped with a ground glass stopper, and well cemented, 
then placed in a strong canvass bag. When the bag was 
drawn in, it was found that the bottle had been crushed into 
many thousand pieces,. The other bottle was very tightly 
corked, but not having been left down a sufficient length of 
time, it came up whole, having filled to within one and a half 
inch. The cork had been driven in and remained so ; but the 
