AB is the axis of rotation, BC an adjustable FIG.
Wiechert has also constructed a seismometer on the same principle, but in which the stationary mass is smaller, being adjustable between 80 and 200 kilos (180 and 440 lb).
One form consists of adjustable diagonals, rods or bars, properly fastened to the columns in the building; these diagonals may run through one floor and be attached to the columns at the floor above.
The con - nexion with the hori - zontal bar is through the medium of an adjustable cam.
The magnet between the poles of which the rectangular signal coil moves is built up of a number of thin flat horseshoe-shaped permanent magnets of a special quality of steel, and is provided with adjustable pole pieces.
This in its simplest form consisted of a ring of wire nearly closed terminating in spark balls very close together, adjustable as to distance by a micrometer screw.
A metal contact-piece adjustable by a screw could be made to just touch a point at the centre of the disk.
D and spark gap, has the same natural time period of oscillation as the open circuit consisting of the antenna, secondary coil and adjustable inductance.
The mechanic's instrument known as a bevel consists of a rule with two arms so jointed as to be adjustable to any angle.
It then possesses four adjustable constants, and more can therefore be expected from it.