ing operation was that due to the tide, and it sometimes happened when weather conditions were unusual that the tide did not serve in accordance with the rules.

The gear used by the United States vessels in France in mine sweeping is known as the "Ronarc'h drag," or "single ship drag. A sweep consisted essentially of two cables in the form of a large V, the ends of which were held out by means of submarine kites, which in turn were maintained at a set depth by means of floats. On each arm of the drag several shears were placed which had explosive knives mounted on them for cutting the cables. The apex of the V was connected to a single wire. The apex of the V was held down by means of a plunger plate which acted on the same principle as the submarine kite. The whole was led over the stern of the vessel to a small steam winch which was used for letting out the drag or hauling it in. The speed of the trawler was reduced considerably by having to tow this drag, the revolutions for ten knots in free route giving about 5 to 6 knots when dragging.

The operation of putting over the drag from a sweeper with a well-trained crew consumes anywhere from four to six minutes. First the floats are put over and second the kites. As soon as the kites are in the water and are heading in the proper direction and diverging, the explosive shears are put on. The explosive shears number about seven or eight on each arm of the V and are put on as the cable is being paid out. As soon as the apex of the V is reached the plunger plate is attached by means of a shackle and the single cable paid out until the plunger plate has assumed its proper depth. This depth is determined by the angle which a single cable makes with a horizontal. The apparatus is then clamped, lookouts are stationed aft to report any mines cut, a lookout is stationed aloft to detect, if possible, any mines ahead, and the sweeping operation begins.

When the vessels first attempted to put over a drag, there were many amusing as well as perplexing difficulties to overcome, but patience and persistence finally won out and the art was mastered.

The formations employed were in general of three kinds : the starboard quarter formation, the port quarter formation and the wedge formation. When sweeping convoy routes on "exploration" sweeping, the wedge formation was generally used. In exploration sweeping the vessels covered a very much wider

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area than when dragging on a known field. Each sweeper could drag a width of about 200 yards. The quarter" formation was used when dragging on known fields, the second vessel maintaining his position using the float of the leader as his guide, keeping in such a position that the drags overlapped. In this way no "holidays" would be left in a mine field. The third and fourth kept position on second and third, respectively.

Any one who has done any coastal navigation along the rocky shores of France knows full well the varying tidal conditions one meets, and the unexpected surprises in the way of rocks and shoals. Not only can the rocks be found close inshore, but some project several miles out at sea in the form of delightful menaces to navigation, as well as landmarks. A joy by day becomes a menace by night, and many a rock is a life-saver in a dense fog. Owing to the character of the bottom it is necessary to use considerable care in selecting the depth at which to work, in order to be sure the deep spots are swept clear, and at the same time not to neglect the shallow ones. When conditions like this were met, it was our practice to divide the sweepers into groups, some working in shallow water and others working in deep water. In this way there was a reasonable assurance that the entire area was clear. Except on the long convoy routes fairly far from land, the navigational part of mine sweeping was comparatively simple. The French charts are accurate every church, hill, house, barn, lighthouse, semaphore, rock, tower and windmill has a name, and its position is accurately located on the chart. With these landmarks so well defined it was a simple matter to pick out ranges and to use these ranges in determining positions.

It is apparent that accurate navigation is essential, as without it many a "holiday" would be left in a mine field. The leader in all cases bears the brunt of the navigation, as all other vessels take their position on him.

When a course is laid down it is necessary to take observations at intervals of about two to three minutes, and accurately plot the position. One soon becomes accustomed to taking bearings, sextant angles, spotting ranges, and laying them down speedily and accurately. By taking readings at short intervals it is simple to detect the set and drift and correct the course in order that the field may be accurately swept.

The usual number of vessels in one sweeping group when on a mine field is four, although when sweeping one large mine field off the entrance to one of the principal ports of France we used as many as 12 ships, eight of the United States and four French. The sweeping groups on the west coast of France were organized into a French group, a Franco-American group, and an American group.

The convoy routes were swept whenever a convoy was due in from the west, and whenever a convoy left for the west, and in addition the coastal convoy routes were swept every other day from Penmarc'h Point to Buoy d'Boff. This amount of work naturally kept everybody on the job, preventing them from getting homesick, and constantly living in expectation and hopes of getting a mine or a submarine.

If you think the above is all that was done, you have still a few guesses coming, because when the day's work was over on the mine fields, we were frequently called out to patrol areas or "listen in" for submarines.

Our particular submarine friends were Belle Isle Betsy and Penmarc'h Pete. These wily ships have been known to get as many as three vessels in a convoy in one night, and when these little events occurred, it was our particular little job to go out and endeavor to locate these birds by means of the listening devices on board. Many a ruse was used in order to attract the submarine, but no matter how far out we went, or when we started, or when we came in, the sub was never found. One night we thought we surely had one. A great commotion was heard over the sea tube, a noise not unlike the swish of a propeller-whereupon we got its direction and headed full speed, only to find that the source of our noise was a school of fish playing near the surface of the water.

In the midde of March, 1918, while peacefully engaged in clearing the convoy routes in the northern part of our district, we were suddenly informed by radio that mines had been discovered off the entrance to St. Nazaire. This being one of the principal ports of entry for troops and supplies, it was essential that the channel be cleared at once.

The combined forces of the French and the United States worked on this field. The first mine discovered on the field was picked up by a patrol vessel. The mine was adrift several miles