=Care and Adjustments.=—Care must be exercised when a board is installed to make sure that the frame is in a vertical and level position. When assembled at the factory, all adjustments are made with the board in a vertical position and all operations conductive to satisfactory service depends on this prerequisite being observed. The line signals of the monocord switch boards are of the gravity type and require careful adjustment. Any adjustment further than that done at the factory should be made by an expert who is thoroughly familiar with this work. During transportation and installation of this board, the line drop shutters should be held closely by the flat springs previously described. The burning out of a fuse when excessive current comes in on a line that is detached by an open circuit on that line. A bad fuse generally shows plainly against the white background on the panel. However, if it is not possible to see whether or not the fuse is burned out, the line may be short circuited momentarily by means of a piece of bare copper wire placed across the two line terminals. The operators is then inserted in the jack of the unit under test, and the magneto crank turned. If the fuse is burned out, the crank will turn over easy; if not, it will turn hard, indicating that the open circuit is elsewhere on the line. A burned out fuse should be replaced immediately in order to keep all lines working. Several spare fuses should be kept on hand at all times but in case no fuse is available, a strand of small copper wire may be connected across the upper and lower fuse clips. To remove a fuse, take the bottom metal cap of the fuse between the thumb and finger and push upward against the spring holder on the line terminal block, at the same time pulling outward. To install a fuse, hold it in the same manner and put the other end of the fuse in the upper spring contact, forcing it upward until the bottom ends slip into place. Care should be taken to keep the small air gap between the toothed washer and the line terminal clean. If this precaution is not taken, and the air gap is allowed to clog up with dust and dirt, it will introduce a leak to ground or between wires with resulting poor transmission. All mounting screws and all wire connections should be kept tight. Whenever the unit is damaged, it should be replaced by another one, the damaged unit being sent back to headquarters for repair. In this connection it should be noted that the American unit panels and parts have been made interchangeable with the French to facilitate repair. To remove a unit from the frame, it is only necessary to disconnect the line terminals and remove the top and bottom screws which engage the brass bars behind the board. In handling the switchboard cords, they should be grasped by the plug, not by the cord. The connection of the wires to the tip and sleeve of a plug will break, is subject to undue strain or abuse, and by taking hold of the