On the first excursion, June 7th, the American squadron planted a mine field 47 miles long, containing 3,400 mines, in 3 hours and 36 minutes. Everything went without a hitch. One ship emptied herself of 675 mines without a single break, one mine every 11-1/2 seconds through more than two hours, a record never before equalled.

ONE OF THE PERILS OF MINE-SWEEPING

An explosion close astern of the Patapsco. The greatest care was exercised to avoid accidents of this character, but to eliminate them entirely was impossible.

THE MINE-SWEEPERS PROVED WONDERFUL SEA BOATS

These tiny craft rode many a rough sea which worried larger and more powerful ships.

UNITED STATES NAVAL OFFICES IN IMPORTANT COMMANDS

Left to right: Admiral Sims, Admiral Mayo, Captain Nathan C. Twining, Captain O. P. Jackson, Admiral Wilson.