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 fm-ther : " 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 sen abundant specimen of soft gray 

 ooze. . . . That one trial was quite enough to show that the 

 difficulties Avliich 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 successfid 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 



1 Sir William Thomson has also an- rate of silver, measures the height of 



other sounding-machine, with which it the column of water to the pressure of 



is possible to take soundings iu from which the sinker has been subjected, 



twenty to one hundred fathoms in a Soundings of one hundred and twenty 



sailing yacht, without once rounding to fathoms have been made by steamers 



or reducing speed. He accomplishes of the Anchor Line while running at the 



this by the use of a long galvanized- rate of twelve knots. The " Britannic " 



iron sinker, provided with tubes lined has made a sounding of one hundred 



with chromate of sUver. The compres- and thirty fathoms over the Banks of 



sion of the air in the tubes, indicated Newfoundland while steaming at the 



by the line of white lining of the chlo- rate of sixteen knots. 



