EQUIPMENT. 5 
actually submerged at each instant was applied tangentially 
to the circumference of the wheel by the friction of a cord 
wound round a groove in the circumference and kept suitably 
tightened by a weight.” 
He says further: * When from two thousand to twenty-five 
hundred fathoms were running off the wheel, I began to have 
some misgivings of my estimations of weight and application 
of resistance to the sounding-wheel. But after a minute or 
two more, during which I was feeling more and more anxious, 
the wheel suddenly stopped revolving, as I had expected it to 
do a good deal sooner. The impression on the men engaged 
was that something had broken, and nobody on board, except 
myself, had, I believe, the slightest faith that the bottom had 
been reached . . . until the brass tube with valve was unscrewed 
from the sinker and showed an abundant specimen of soft gray 
ooze. .. . That опе trial was quite enough to show that the 
difficulties which had seemed to make the idea of sounding by 
wire a mere impracticable piece of theory have been altogether 
got over." 
The first experiment was made in the Bay of Biscay, near a 
point where the charts showed a depth of twenty-six hundred 
fathoms. It was entirely successful so far as determining the 
depth was concerned ; and although the machinery for reeling 
in the wire was defective, the problem had been solved, and the 
machine only needed very slight modifications to become avail- 
able for general use. "These modifications have since been 
effected, and many ocean steamers in the English service are 
now provided with the new machine of Sir William Thomson.! 
All the steamers of the submarine telegraph companies are also 
! Sir William Thomson has also an- rate of silver, measures the height of 
other sounding-machine, with which it 
is possible to take soundings in from 
twenty to one hundred fathoms in a 
sailing yacht, without once rounding to 
or reducing speed. He accomplishes 
this by the use of a long galvanized- 
iron sinker, provided with tubes lined 
with chromate of silver. The compres- 
sion of the air in the tubes, indicated 
by the line of white lining of the chlo- 
the column of water to the pressure of 
which the sinker has been subjected. 
Soundings of one hundred and twenty 
fathoms have been made by steamers 
of the Anchor Line while running at the 
rate of twelve knots. The “Britannic” 
has made a sounding of one hundred 
and thirty fathoms over the Banks of 
Newfoundland while steaming at the 
rate of sixteen knots. 
