Two small boats, one on each side of the line, work as follows: As soon as a mine is dropped the boat on the corresponding side moves to it, picks up the buoy, pulls the rope taut, notes the submergence of the mine, transmits the data to the planter, and holds up an oar or a flag in prolongation of the buoy rope. The observers at the ends of the base line take observations on this marker and are thus able to plot the position of the mine accurately. This process is repeated for each mine. These boats also serve as guides to the planter in dropping mines by holding on to their buoys until the adjacent mines are planted. With automatic anchors the line may not be marked otherwise than in this manner. After the mine is dropped, the members of the distribution box boat party remove the lashing from the cable, insert the Turk’s-head in the proper slot, make a temporary joint between it and the corresponding conductor of the multiple cable, and telephone to the casemate operator. The latter opens all the power switches on the corresponding operating board, closes switch No. 7 up (this throws D. C. power on the mil-ammeter lead), and then plugs in on the upper jaw of the power switch of the mine under test. If the D. C. voltage be 110, the mil-ammeter should read about 40 mil-amperes; if the voltage be 80, the reading should be about 30. If this test be satisfactory, the joint is made permanent. For the last mine the telephones are removed from the corresponding conductor, a temporary joint is made in the boat, and the test made as above. By arrangement with the casemate operator the mine is left on two minutes for test. At the end of this time the joint is opened and the telephones put back. If the casemate operator reports the test satisfactory, the telephones are again removed and a permanent joint is made. When the last joint has been made, the distribution box is closed and the raising rope fastened to its lid. The box is then lowered. This is done by the distribution box boat if it is provided with the necessary davit and power, otherwise it is done by the planter. Generally the anchor rope is made fast to a buoy by a bowline, and the raising rope of the distribution box is secured to the bight of the bowline. After the distribution box is lowered all buoys are removed except that for the box, and such others as it may be desired to place for marking the ends of lines. The marking boats may remove the mine buoys as they work, provided they are notified from the mine commander’s station that proper observations for plotting have been obtained. Such notification is usually sent by telephone to the distribution box boat. In time of war decoy buoys judiciously placed would be very useful in deceiving the enemy. CHAPTER VI. TESTS OF MINES AND APPARATUS.