316 IDEAL HOME LIFE
make. A consists of a tomato can with a small pipe out of which the water flows. As the water runs out, the time is noted, on the same principle that you have seen illustrated when the sand ran out of the little glass on your breakfast table, when your mother was timing your egg. C is made of three cans. You know that the more water there is in a can the faster it will run out, so the interval changes as the water gets lower. To overcome this several cans are used, and the water in the can next to the bottom is kept at the same level by an overflow pipe in the can above. Can 3 in C contains a float with a rod in it, which rises with the float, as the water runs in. A stick with marks to show hours, halves, and quarters may be fastened to the can, and as the float rises the rod will point to these lines. D can be made of a broken saw and a clock wheel. The idea is the same as in C.
If a more elaborate water clock is wanted, drawing F may be followed. The principle is the same as above. Get an old box which will easily hold your cans, put in shelves for them. In can 3 put a float to which is attached by a string a weight. Just above can 2 put a half-inch dowel rod which will revolve. On the front of the box put a clock face, and to the dowel attach a copper or some kind of hand. Make a small door in the side of the box to get at the cans.
Fill can 1. The overflow will run into can 2, while the rest runs into 3 and raises the float which makes the dowel rod revolve and moves the hand. Can 3 should fill in about an hour. Find out by experiment how to keep the water at the same level in can 2. The surplus overflows into can 4.
tc& «5» «<5*
Wind and Weather Gauges
by grace vincent
The vane given in Figure 26, A, is made of 1/2-inch wood, and laid out in one piece. This may be made any size, but