No throw of the dice was ever watched more intently than those first proof tests. Upwards of forty million dollars had been staked on them and were already half spent. Results on the first day made us feel easy, but it was two days more—from various delays—before we succeeded in exploding a full loaded mine. This had been planted in Chesapeake Bay, well marked and guarded, in the very same deep hole where a whirlpool effect troubled the German submarine _Deutschland_ on her first return trip. It was not possible to place the mine far from the fairway, however, since the water elsewhere was not deep enough for our purpose. Early the second morning, the battleship _Arizona_ came along, heading too near it. The signal “You are standing into a minefield!” sent her rudder hard over and engines full speed astern. We could see the mud stirred up, from two miles away. Since we could not get the mine up, what a relief it was when it was set off at last by sweeping! The final proving of the mine as a whole, which was completed in April, off Cape Ann, did not take place until after several cargoes of mine parts had been shipped abroad, but the mine’s success, from its first trials, showed how careful and observant had been all those who were concerned in its designing and testing. The prospect in October was that the shipment of mines would begin in January, but through delay in completing the detailed plans and from the abnormal industrial conditions prevailing, these shipments did not attain a regular flow until May, so that the ships and the mines were ready together. Secrecy, as well as timely delivery, caused the manufacturing to be partitioned among 500 contractors and sub-contractors, some of them as far west as the Mississippi. Certain mine parts from different makers were put together by still others, and all parts flowed toward Norfolk, Virginia, the trans-Atlantic shipping point. Planning this dividing up, placing the contracts, and arranging for the inspection of all—taking into account the transportation involved and the many different kinds of firms—wire rope makers, automobile concerns, foundries, machine shops, electricians, die-presses, and even candymakers—it was indeed a complex web. What tireless industry and what endless patience under pressure went into this work, only Commander Fullinwider and his assistants can fully appreciate.