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314 IDEAL HOME LIFEFigure W is called a stile or gnomon. Before making this, one must know the latitude of the place in which he lives. This may be found in any geography, or any teacher will help a boy to lay out the figure and explain the way the dial works. The angle at E in drawing W represents the latitude of the place (New York, in this instance). The back of the stile may be cut away as in drawing at G, as long as the angle at E is not changed.
For the face of the dial draw the line AB, then the line CD at right angles to AB. The points C and D will be your six o'clock points. Where the lines cross at B, draw a circle with radius EF, in Figure W. Then another circle with radius equal to the base of Figure W. Divide your half circle into six equal parts, then each of these into two equal parts, making twelve as points 1, 1, dotted line. The inside one the same, 2, 2. Draw lines parallel to CD, from each of the points of division in the two quarter circles, then draw lines parallel to AB, from each point 2 on the inner circle.
Marking the points where the lines cross, from the central point B, draw lines across the intersection, and where these lines cross the circles will be your hour-points. The half and quarter hours may be made the same way.
In laying out a dial in this way no allowance has been made for the width of stile. If a thin stile, like 1/16 inch, no allowance is made, but if 3/16-inch or 1/4-inch wood is used, then in- . stead of line AB, there must be two parallel lines the same distance apart or the width of the gnomon, and instead of using B as a center for the compass, two semi-circles must be made. An easier method would be to cut the draft into two equal parts along the line AB, and place between them a strip of paper the width of the gnomon.
Writer ClockPeople who are fond of old-fashioned gardens still have their sun dials, but there was another way of telling time which is very interesting although not used now, from which sprang our own clocks. This is called the clepsydra or water |
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