Chemistry.
The science treating of atomic and molecular relations of the elements
and of chemical compounds of the same.
Chimes, Electric.
An apparatus employed to illustrate the principles of the electrostatic
charge, involving the ringing of bells by electrostatic attraction and
repulsion. It is used in connection with a frictional, or influence
electric machine. Two bells are employed with a button or clapper
suspended between them. One bell is connected to one of the prime
conductors, q. v., of the machine. The other insulated therefrom is
connected to earth, or if an influence machine is used, to the other
prime conductor. The clappers are hung by a silk thread, so as to be
entirely insulated. On working the machine the bells become oppositely
excited. A clapper is attracted to one, then when charged is repelled
and attracted to the other, it gives up its charge and becoming charged
with similar electricity to that of the bell it touches, is repelled and
attracted to the other, and this action is kept up as long as the
excitement continues, the bells ringing continuously.
Fig. 84. ELECTRIC CHIMES.
Chronograph, Electric.
An apparatus for indicating electrically, and thereby measuring, the
lapse of time. The periods measured may be exceedingly short, such as
the time a photographic shutter takes to close, the time required by a
projectile to go a certain distance, and similar periods.
A drum rotated with even and known velocity may be marked by a stylus
pressed upon it by the action of an electro-magnet when a key is
touched, or other disturbance. Then the space between two marks would
give the period elapsing between the two disturbances of the circuit. As
it is practically impossible to secure even rotation of a drum, it is
necessary to constantly measure its rate of rotation. This is effected
by causing a tuning-fork of known rate of vibration to be maintained in
vibration electrically. A fine point or bristle attached to one of its
arms, marks a sinuous line upon the smoked surface of the cylinder. This
gives the basis for most accurately determining the smallest intervals.
Each wave drawn by the fork corresponds to a known fraction of a second.
For projectiles, the cutting of a wire opens a circuit, and the opening
is recorded instead of the closing. By firing so as to cut two wires at
a known distance apart the rate is obtained by the chronograph.
Synonym--Chronoscope.