LZ2 OF THE MENSURATION

Paris ? This is the question, upon which every-thing relating to this subject depends. Sir IsaacNewton considered it in the following manner.The diurnal rotation of the earth is performedround an imaginary line, which passes throughthe two poles; and as the equator is fartherdistant from its center, than any other circlewhich is parallel to it, it is plain, that thoseparts of the earth which lie under the equator,will move with a greater velocity than thosewhich are nearer to the poles ; and of course,the equatorial regions will become more ele-vated than the polar ones; so that if the earthwere an entire fluid, and the waters met with noobstacles in their progress, they would recedefrom the poles towards the equator, and by thatmeans flow in continually till they had formedan equilibrium, and could rife no higher.

This tendency of bodies to fly off from thecenter round which they move, is called thecentrifugal force, the nature and existence ofwhich, may be made evident in a number ofways. When a mop is turned upon the arm,by a quick circular motion, the threads, orthrumbs, are observed to rise highest in themiddle ; and the swifter the mop is whirled, thegreater will be the force, and the particles willfly off with the greater velocity. The famething is observable, when a stone is turnedswiftly round, by means of a fling; the arm

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