16 
per square inch. It was about 14 inches long and bent in 
the form of a square-ended siphon. The gap in the wire 
was about J inch, and the water extended about IJ inches 
on each side of the gap. The ends of the pipe were open, 
and the jar charged in the same manner as before with 
about 100 turns of a 12 inch plate machine. The surface 
of the jar is about a square foot, and the discharge when 
effected with the common rod took place through about 
2 inches of air. 
This tube was shivered at the first discharge. That part 
opposite the gap and for some way beyond is completely 
broken up into fragments which present more the appear- 
ance of having been crushed by a hammer than of being the 
fragments of a pipe burst under pressure. Some of the 
fragments show that the interior of the pipe has been 
reduced to powder. 
These fragments were scattered to some feet on all sides, 
but there was nothing like an explosion. I held the pipe 
in my hand at the time of the discharges, and the sensation 
was that of a dead blow. There was no noise beyond the 
ordinary crack of the discharge. 
The manner in which this pipe was destroyed clearly 
showed that a larger one might have been broken. But as 
it was two o’clock and my fire was out, I did not continue 
the experiments. 
It is not easy to conceive the precise way in which a 
pressure of probably more than 1,000 atmospheres could be 
produced and transmitted in a pipe of water the ends of 
which were open. It might have been caused by the sud- 
den formation of a very minute quantity of steam, or by 
the expansion of the water; but whichever way it was, its 
effect was due to its instantaneous character, otherwise 
there would have been an explosion, 
When we consider the great strength of this pipe (which 
might have been used for a gun without bursting), and when 
