222 Journal of the Asiatic Society of Bengal. [N.S., XVIII, 
The problem resolves itself into— 
(1) “Making” the 3 circuits in the correct order with 
an interval of (say) 5 seconds between each ‘‘ make.” 
(2) Keeping the circuits ‘‘made”’ for 5 minutes (ist 
stationary state). 
(3) ‘‘ Breaking ’’ the 3 circuits in the reverse order. 
(4) Keeping them “ broken” for 10 minutes (2nd sta- 
tionary state). 
An American clock (Fig. 1) with an alarm system is 
employed to actuate the various keys. The axis 00’ (which is 
the axis of the striking system 
in the clock) and all wheels 
and cams on it (P, Q, R, 8, e) 
remains stopped or can be 
rotated by the clock: if free 
to rotate 00’ makes one revo- 
lution in a few seconds, during 
which, 
(i) Excentric cam Q actu- 
ates a lever L which 
depresses D into its 
mercury cups 
« makes ” the heating 
circuit ; 
(ii) The contact piece 
m 

bi 
(iii) Excentric cam P actuates a plunger F which“ makes’ 
the coil primary circuit and starts the tube. 
According to the angular adjustment on the axis of the 
two cams P and Q and the contact piece e the order of the 
above operations is determined. The order of contacts is 
actually that described above. 
The process by which the motion of the axis 00’ is started 
and stopped so as to produce 5 seconds intervals between 
the 3 contacts and 5 and 10 minute stationary states, 18 7° : 
follows :— 
The axis 00’ is set in motion by a double release system *— 
(i) by the lever M disengaging from the slots r of r’ on 
the wheel R, in which case the axis is free to rotate 
ie through 180° unless prevented by ; 
(ii) the catch N which engages with a pin on the wheel C 
and stops the motion of 00’ even if M is raised. 
(Figs. 1 and 2). 



