Connection is made from the stopcock R to the hose connection on the lantern proper, and this is the passageway of the gas from the generator to the burner. As soon as the stopcock is opened the water rises through the tube and flows to the carbide. The advantage of the cartridge being submerged in the water is to reduce and absorb as much of the heat liberated by generation as is possible. These lanterns have been tested up to a distance of 10 miles with the naked eye, and under favorable conditions can be used over a range somewhat in excess of this. With a 30-power telescope the flash can be read at a distance of 30 miles.
Operation and care.—Take the lamp and generator from the case by aid of the handle attached to the lamp; screw the complete outfit on a heliograph tripod, or stand the outfit on a level object; remove the cover of generator, to which is attached the flexible frame ([fig. 9]); detach spring from the catch of the flexible frame; tear off flaps from the ends of carbide cartridge (or pry off small caps) and attach the cartridge as shown in [figure 9]. Then attach to frame as shown in [figure 10], being careful to see that both rubber plugs fit tightly into the holes in the cartridge; fasten the latch of the spring over the metal catch; close stopcock R on service pipe; completely fill the outer can of generator with water, the object being to have the generator level full of water when the lamp is in service, then immerse the frame and cartridge, pressing the top of the generator down tight. In doing this the water will overflow the sides of the generator tank. Now connect by rubber tubing the stopcock with the gas inlet at the bottom of the lamps, as shown in [figure 4]; then (1) open front door of the lamp, (2) light a match, (3) open stopcock, and (4) light the gas at the burner. In doing this hold the key open. In the new model the key and hose connection are on the side of bottom of lamp.
When the gas is ignited, the lamp is ready for signaling, and the key can be operated as is the Morse telegraph instrument, but of course not so rapidly.
In the event of the flame being too high when the key is closed, adjustment can be made by loosening the set screw ([fig. 4], indicated by an arrow) and adjusting the light by turning screw b. When at the proper height, tighten the set screw which locks the by-pass in its proper position. In the new model this is accomplished by aid of the regulator by-pass valve at the left-hand side of bottom of lamp. The lamp is properly adjusted when shipped and should not be changed unless absolutely necessary. Connect the rubber tube to the burner before opening the stopcock on the generator.
To recharge the generator, take the frame and the old cartridge from the case, throw away the old case and replace with a fresh one, proceeding as before. See that fresh water is put in the generator each time a new cartridge is used.
Fig. 7.
In the tube through which the service pipe passes is a felt filter for taking the dust out of the gas. If the filter clogs, unscrew the cap to which the service pipe is attached, clean the felt, or replace it with a new filter, binding it in place by a stout thread or string.
If the burner of the lamp does not produce a perfectly flat flame it has become clogged and should be cleaned with the burner cleaner furnished, or a new burner should be substituted, care being taken to put a little white lead on the nipple, if practicable, so as to insure a tight joint.