1316 
IV. The electro-magnetic clamp K,. Except during the period of 
rest, this clamp must remain closed and consequently is in circuit. 
Therefore it has been arranged in such a way, that a current of 0,45 
Ampere is sufficient. For the rubber tubes 17 and 19 has been used 
common bicycle valve-tube. 
V. The: pulley-contact-arrangement. The pulley-shaft runs very 
lightly between two conical pivots. The floater is made of glass 
and contains mercury at the bottom. A thin cord runs over one 
pulley and bears a weight at its other end. In fig. 4 to the right 
is shown, that in the newest model the second pulley is larger, 
which magnifies the movement of the forks 8 and 9 and enables 
us to fix the contacts C, and C, more accurately. 
As appears from the description, | have always used mercury 
in the contact-arrangements, which was done because mercury- 
contacts are absolutely trustworthy, contrary to brushes of other 
metals and because force is not wanted for bringing about the 
connection. 
It would not be an easy matter to keep the mercury in the 
glass tubes C, and C, clean, when soiled by sparks. With the 
amperage used sparks only occur on breaking the current, therefore 
it was necessary to break the cireuits [ and Il somewhere else 
before the forks 8 or 9 rise out of the mercury. This end has been 
attained by adding to 
VI. the automatic mercury switch, an arrangement of levers (not 
shown in fig. 1), by which, again with the aid of mercury- 
contacts, the circuits | and II can be broken, when the switch has 
reached the required position and further action of the solenoids 
S, or S, is superfluous. With this arrangement a double purpose 
has been attained: 18* the spark of breaking is removed to a place 
where the mercury must not so anxiously be kept clean; 2rd the 
loss of electricity in the solenoids is limited to a minimum. — 
At the first trials of the switch it appeared, that in consequence 
of the elastic fall of the iron forks in the mereury-cups, the switch 
recoiled halfway after a moment. To prevent this, the clockmaker 
J. Mussias devised a brake, consisting of a couple of metal springs, 
checking the movement of the lever. One of them has been rendered 
in the diagram as No. 23. 
The mercury-cups of the contacts C, to C, are bored out in 
ebonite blocks. At the bottom of the cavities there end the iron 
screws of the “terminals” put up at the sides, carrying the current 
to the mercury. 
VIL The clockwork U,. The proportion of the cog-wheels and the 
