March 30, 1883.] 



SCIENCE. 



215 



in Fig. 13. In this arrangement, the terminals 

 to which the conductors from the lamp and 

 those from the two machines are connected have 



practicallj' the same relative positions as in 

 the previous case. From these terminals pass 

 stout copper strips, which can be clamped bj' 

 binding-screws bearing the same numbers as 

 the terminals. The locking-pieces in connection 

 with tne terminals of the machine can be con- 

 nected b^- thick copper strips bj' the binding- 

 screws corresponding to the lamp-cables ; and 

 to facilitate this coupling, the locking-pieces 

 are more or less raised, so that the strips may 

 cross each other without touching. In this 

 waj' perfect contacts are obtained ; but a longer 

 time is required to change the combinations. 

 Fig. 13 shows the connections when machine 

 No. 2 is coupled for quantity. Fig. 14 allows 

 the difference in height of the locking-pieces 

 to be seen, and shows how machine No. 1 is 

 coupled for quantit}-. 



The metallic rails upon which the regulator 

 rests have already been described. These 

 rails are in direct communication with the large 

 cable ; and it is bj' them that the current arrives 

 at the frame of the regulator, and thence to 

 the carbons. The cable of the electro-magnet 

 and the small cable are attached to two termi- 

 nals (H and H', Fig. 15) with insulated springs. 



These springs, pressing on two contacts under 

 the lamp, make the appropriate connections. 



The regulator itself is a combination of the 

 Serrin and Berjot lamps. It comprises the two 

 electro-magnets of the latter lamp, the arma- 

 tures of which form an internal core, — one 

 magnet having coarse wire, and placed direct 

 in the circuit ; the other having fine wire, and 

 mounted in a derived current. The former 

 acts on the articulated frame carrj'ing the lower 

 carbon ; the latter acts on the disk brake con- 

 trolling the clock-work. 



Fig. 15 shows at S the electro-magnet with 

 coarse wire acting bj' the arm Q on the frame. 

 R and R' are the springs which tend to raise 

 this frame. L is the lever which serves to regu- 

 late the tension of the spring R : it is controlled 

 by a screw, V, which can be turned by insert- 



^^^- 



ing a key at the hole O. The magnet with 

 fine wire is placed sj'mmetricaUy with the other 

 on the opposite side of the clock-work. 



