Page:Popular Science Monthly Volume 29.djvu/203

Rh round, it would strike j to the left. The effect would be this: g would move to the right and i to the left, thus pushing the weight at i from the little shelf on which it was balanced, and causing it to tumble toward the floor.



You can imagine that the force set in motion by the hour-hand of the watch, even of a "bull's-eye," was not enough to start a very heavy weight. Therefore, the dropping of the weight at i was not enough of a noise to awaken the boys, but the force that was exerted was enough, applied at the end of a long lever, to transfer itself to a point where it would do more good. The weight i, in dropping, pulled a string that was fastened on the long arm of the lever k m. This lever was fastened to the edge of the same table that held the square board by a gimlet, or nail, as a fulcrum, at l. When i dropped, it pulled k down and pushed m up. The sudden jerk at m pushed over a nicely balanced table, upon which had been placed nearly all the chairs and other furniture in the room. This certainly made enough noise to awaken the occupants of the room, and it is not likely there was much sleep after that. It was a great deal of trouble to adjust so nicely all the different parts of this primitive alarm-clock; but it never failed to work when care was taken with all the details. Let us praise the boys for studying out a scheme which others have adopted and called their own. They preferred to lie in bed as long as possible, and did not propose to keep awake all night, if any machinery could be devised to do the awaking for them.

A few words in regard to the dial on the face of the clock. The dial of a clock, if it is a cheap one, is made of wood and painted white. If the dial is small and expensive, it is made of copper on which is baked a white enamel surface. The figures are marked in black paint, which is sometimes burned or "baked in." The usual size of the