240 



ELECTRIC LIGHTING. 



FIG. 2. 



the ratchet-wheels; but when the current in- 

 creases, from the turning out of any of the 

 lamps in the circuit, the electro-magnet shown 

 above the gearing becomes strengthened, and 

 draws down its armature. By means of the 

 connecting-rod from the lever carrying the 

 armature to the reciprocating pawl, this latter 

 is depressed, and then engages with the lower 

 ratchet-wheel, which is moved one tooth with 

 each vibration of the pawl The spur-wheel 

 on its shaft turns the intermediate one, caus- 

 ing the brushes on the machine to be shifted 

 toward the neutral points, lessening the cur- 

 rent. When the strength of the lamp-circuit 

 diminishes, the armature of the electro-mag- 

 net is drawn away by the spring on the farther 

 end of the leve.-, and the pawl then engages 

 with the upper ratchet-wheel, which shifts the 

 commutator-brushes in the reverse direction, 

 increasing the current furnished the field of 

 the generators. 



The lamp known as the Sawyer-Man lamp, 

 illustrated in the " Annual " of 1878, has been 

 further improved by Mr. Sawyer, and is now 

 pronounced by him to be perfected. The change 

 in the new lamp consists in substituting for the 

 small piece of carbon a thin pencil, some eight 

 inches long, which is slowly fed upward as it 

 wastes away. The waste is stated by Mr. Saw- 

 yer to be from one hundredth to one fiftieth of 

 an inch per hour, giving the carbon a life of 

 from four hundred to eight hundred hours. 

 When entirely consumed it can be replaced at 

 a small expense. By means of a switch, oper- 

 ating so that the current is gradually admitted 

 to the lamp, the light can be varied, as with a 

 gas-flame. Four lamps, each giving 27*4 can- 

 dles, the inventor states, can be maintained per 

 horse-power. Mr. Sawyer has also designed a 

 lamp-regulator (shown in Fig. 3), which acts 

 by inserting a greater or less number of re- 



sistances in the circuit as 

 the number of lamps in use 

 varies. He states that it 

 works satisfactorily, but is 

 of the opinion that such de- 

 vices are not of sufficient 

 value to have a place in a 

 system of general lighting. 

 Resistance - coils are placed 

 in the base and connected 

 with the studs F, so that 

 the current which enters at 

 the base of the insulated 

 contact plate E, and tra- 

 verses the arms H and G, 

 will pass through a greater 

 or less number of them as 

 the arms G and H rise and 

 fall. This movement of the 

 arms is effected by the cyl- 

 inder A, which moves tightly 

 in the cylinder B. Water 

 is admitted by the tube D, 

 and flows out by the pipe O. 

 A tightly fitting piston, 0, 

 has two valves, K and M, which are closed 

 by the lever L, operated by the electro-magnet 

 K. When the core is not magnetized, the valve 

 N is opened, and water enters above the piston 



FIG. 8. 



ESI 

 E2 

 BS 



E34 

 E3 

 EG 

 E7 

 EJS 

 EO 

 E lo 

 EH 

 E12 

 E13 

 EH 

 JFG15 

 E 16 

 E17 

 EH 



and raises the cylinder A. When the core is 

 magnetized, the armature is attracted, and opens 

 the valve M, allowing the water to flow out 

 and the cylinder A to fall. 



