M. Lege had constructed a towing fish-torpedo from which he expected great things. Its cost was insignificant when compared with the Whitehead torpedo; the principal mechanism being that which kept it at any desired depth while it was drawn along. The main part of the body of the torpedo was filled with cork, which was found to be cheaper and more serviceable than any airtight construction. The inventor proposed that at sea a torpedo boat would tow the torpedo at the end of 1000 yards of very fine wire, moving so as to place the torpedo on the far side of an enemy's vessel, and then hauling it in so that it struck the ship's far side below the waterline.