REGULATOR. In machinery,. a gen eral name for any contrivance of which the object is to produce the uniform movement of maohmes. The regulators most commonly applied are the fly and the governor, for which see the respective terms.
The regulator of a watch, is the spiral spring attached to the balance. This in genious contrivance, the invention of Hooke, has contributed as much to the improvement of watches as the pendul nm to the improvement of clocks.
The present Astronomer Royal of En gland has investigated the mathematical problem of the motion of the regulator applied to the clock-work by which mo tion is given to large equatorial telescopes. For this purpose, absolute uniformity of motion is of very great importance. The construction, usually adopted, in this country at feast, depends on the same principle as that of the governor of the steam-engine. Two balls, suspended from the upper part of a vertical axis by rods of a certain are made to ex pand by the rotatory velocity of the axis ; and when the expansion reaches a certain limit, a lever is pressed against some re volving part, whereby a friction is pro duced immediately cheeks the ve locity. Now the uniformity of the ro
tatory motion of the.spindle depends up on the assumption, that if upon the whole the retarding forces are equal to the ac celerating forces, the balls will move in a circle, and in no other curve. But this assumption is incorrect; for the halls may move in a curve differing insensibly from an ellipse; and, in some instances, Mr. Airy observed the balls to revolve in an ellipse of considerable eccentricity. When this takes place, the rotatory mo tion of the spindle becomes exceedingly variable. This injurious effect may be partly counteracted by constructing the apparatus so that the revolutions shall be either very slow or very quick ; the for mer method has the effect of giving great er smoothness of motion, but the second insures more completely that the object observed shall remain steady in the field of the telescope.