STORAGE CELL (DISMANTLED)

Fig. 103.

(b) If specific gravity is very low take out some electrolyte and add 1.200 specific gravity electrolyte. (This used to be 1.400.)

7o Keep battery-room well ventilated, especially while charging.

8o Never bring an exposed flame into battery-room while charging. (The gases given off are explosive when mixed with air.)

9o Keep the floor and all parts of the room clean, iron, copper, and metal work free from corrosion; keep all connections tight and clean; never allow verdigris to collect anywhere.

Q. Describe a searchlight.

A. It consists of an iron cylinder mounted on an iron pedestal in a yoke. The cylinder contains a parabolic mirror in the back, a series of glass strips in the front, and two "carbons" in the middle.

The electric current in passing through the carbons heats the points to a very high degree, producing a brilliant light. This light is reflected by the mirror towards the front, and the mirror, being of a curved form, also converges the rays of light. Underneath most searchlights are electric motors for traversing and elevating, and these motors are started or stopped by means of switches in a contrivance called a "controller," which is always placed at a distance from the light.

Q. Point out the following parts of a 36" searchlight: hand star-wheel for slow vertical movement; wheel for throwing out split nut used for connecting or disconnecting the drum from the base mechanism; wheel for slow horizontal movement; hand star-wheel for clamping turntable to center-pin for electrical control; wood handles on drum for moving drum by hand; hand-wheel for clamping hand star-wheel A when electric control is used; controller-switch; controller-handle; controller fuse-box; controller-coupling for connecting cable from the projector; focusing-screw; socket for inserting wrench to operate lamp-switch used for cutting out feeding-magnet; socket for inserting wrench when feeding by hand; door used for adjusting the carbons and for cleaning the front door; door used when carbons are to be adjusted or changed; front door; door used when adjusting negative carbons or cleaning the mirror; horizontal peepsights; vertical peepsights; sliding case to be opened when lamp mechanism is to be inspected; projector main switch; latches for fastening base-sheeting; base-sheeting.

A. See Fig. 104.