In the first of these illustrations we have the “Governor” of the steam-engine, that wonderfully ingenious and simple piece of mechanism which controls the force of the steam, and, without the superintendence of man, acts almost as a living being might.
It is composed of two heavy metal balls, hinged, as shown in the illustration, to a movable collar which slides up and down the central rod. When the engine is at work the Governor revolves, and the harder it works, the more rapid is the revolution. Consequently, as it revolves, the balls diverge and draw the sliding collar up the rod.
Here lies the whole beauty of the invention. The sliding collar is connected with the safety-valve. Thus, if the engine should be working beyond its proper powers, the Governor draws up the collar, and releases sufficient steam to take the undue pressure off the boiler. Thus the engine may be left, so to speak, to manage itself.
Next are shown two examples of Centrifugal Force as applied in ancient warfare, namely, the Sling, which is now retained merely as a boy’s toy, and the Amentum, which was practically a sling attached to a spear. Both weapons have been superseded by the modern firearms, but the Sling is really a more formidable offensive weapon, in skilful hands, than is generally suspected.
A good slinger is as sure of his aim as a good rifleman, and can send his missile to a wonderful distance. Were I to be armed with the best pistol hitherto invented, I should be sorry to fight an accomplished slinger, unless under cover.
The really tremendous power of the Sling is obtained by Centrifugal Force, the weapon, with its missile, being whirled in the air, and then one string being loosed with a peculiar knack something like the “loose” of a good archer. In consequence, the centrifugal force is converted into direct force, and the missile flies directly forwards.
The Amentum is simply a cord tied to a javelin, so that the thrower has the advantage of a lever, which, after all, is only the conversion of centrifugal force.
The very familiar Mop, flinging off its moisture to a considerable distance, needs no description; but I have introduced it to show the action of centrifugal force in small as well as in great things.
The next illustration shows how this very same power acts upon the greatest as well as the least of objects, and enables them to maintain positions which otherwise they must of necessity fail to do. Take, for example, our own Earth, and its peculiar position of being tilted on one side, so as to give us the alternative seasons as it flies on its annual course.