REGULATOR

In Machinery, a general name for any of which the object is to produce the uniform movement of machines. The regulators most commonly applied arc Uiefly and the governor, for which see the respective terms. The regulator of a watch is the spiral spring attached to the b dance. This ingenious contrivance, the invention of Hooke, has contributed as much to the improvement of watches as the pendulum to the improvement of clocks. In a paper published in the Memoirs of the Koyal A str on mai cal Society, vol. xi., the present Astronomer Royal has investigated the mathematical problem of the motion of the regulator applied to the clock-work by which motion la 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 least, 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 length, are made to expand by the rotatory velocity of the axis; and when the expansion reaches a certain limit, a lever is pre ed against some revolving part, whereby a friction is produced which immediately checks the velocity. Now the uniformity of the rotatory motion of the spindle depends upon the a umption,that if upon the whole the retarding forces are equal to the accelerating forces, the balls will move in a circle, and in no other curve. But this a umption is incorrectforj the balls 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 motion of the spindle becomes exceedingly variable. This injurious effect may be partly counteracted Uy constructing the apparatus so that the revolutions shall be either very slow or very quick; the former method has the effect of giving greater smoothne of motion, but the second insures more completly that the object observed shall remain steady in the field of the telescope. [s. 1060]