out.

The second mine was discovered several miles from the first by avion. These two mines being so widely separated made the exact location of the mine field difficult, so that it was necessary to use a large number of vessels to explore for the exact location of the field. An area six miles wide and ten miles long was declared dangerous and closed to navigation. This large area had to be completely swept in order to be sure to get the mines. The low-powered vessels worked close inshore while the larger sweepers worked farther out. By figuring very closely on the tides it was possible, with the draft of our vessels, to sweep safely about five hours every day. The first sweep was made and no mines discovered. On the second day of the sweeping operations four mines were cut, three having been cut by one United States vessel and the fourth by a French vessel. Up to that time, three was the greatest number of mines which any one United States sweeper had cut on any one day.

The location of these four mines was such as accurately to determine the line of the field, and for the next week sweeping operations were conducted by small groups of sweepers. In all 12 mines were discovered or cut in that area in one week. Several of them were exploded and several sunk by gun fire and two of them were exploded submerged, the mine-sweeping gear striking the antennæ of the mines instead of cutting the cables. No mines were fouled by the gear, so that the score for the sweepers on that mine field was perfect.

On the particular day that the location of the mine field was accurately determined by the cutting of four mines, we had assisting us in the work of location, a captive balloon, several flying boats, patrol vessels, and the auxiliary vessels which were used to shoot up the mines.

As a spectacle the operation on that day has never been equalled. The weather conditions were ideal and all hands returned to port that night feeling that a good day's work had been accomplished.

For a mechanical device, the Ronarc'h drag, in the hands of amateurs, possesses more peculiarities and queer traits than even the crankiest of cranky automobiles.

The system of signals used was simple. It consisted of signals of formation, signals for putting the drag over, taking it in, and such casualties as one might expect. The signal for cutting the

mine was the tooting of the whistle. When a mine was cut the sweeping division continued on their course as previously planned, the mine being sunk by a small power boat which accompanied the sweeping group. In case no extra vessel was taken along the duty of sinking the mines fell to the lot of the last vessel in formation. He would upon discovering a mine floating, take in his drag and proceed to sink the mine..

The rules of the Hague Convention required that a mine when it came adrift was to be rendered harmless. The German mines were rigged with a device for extracting the primer when a mine came adrift, but I am firmly convinced that every floating mine was dangerous, because all mines which were captured and examined indicated that the releasing apparatus was not properly attached. Whatever rules there were in regard to mines, the enemy religiously violated them.

It is believed that neutral vessels were engaged in laying mines off the French coast, and it is likewise known that German submarines mostly laid mine fields off the French coast.

The lines of mines were laid usually in the shape of U's, V's and L's, generally on some well-known navigational range or

within the circles of visibility of more prominent navigational lights along the French coast. Toward the end of the war there was no particular regularity in their methods of laying mines, owing to the fact that their Kultur was either lived down or outgrown to such an extent that the submarine captains dared to exercise a little originality. The mine fields were generally laid by submarines engaged solely in this diabolical occupation.

German submarines engaged in laying mines were very particular not to be seen or discovered prior to laying their mines,

and likewise seldom engaged in attacks on merchant vessels until after the mine fields had been laid, and then generally in a zone far removed from the mine field..

A case is on record of a vessel laying a mine field in the vicinity of St. Nazaire and sinking vessels in the Mediterranean Sea.

The operation of the German mine is entirely an automatic one. The mine with its anchor is a complete unit and is carried in a torpedo tube from which it can be fired, or is carried in a tunnel in the submarine from which it is released. Mines may be laid either submerged or on the surface, the chances being that the majority of the mines were laid with the vessels travelling