ividing is
easily done with a pair of compasses, a ruler, and a sharp lead-pencil.

Now we will explain the indicator. It is made of three pieces--a base
and two uprights. The base is fifteen inches long, three wide, and
three-quarters of an inch thick. The uprights are of the same thickness,
and about seven inches high. They are morticed into the base, and have
the shape shown in the picture. A hole half an inch in diameter is bored
through the upright at A, and another at B. Over each of these holes
pieces of tin are tacked, with a little hole in the centre about as
large as a pin's head. When the sun-dial is placed in position, the sun
shines through these holes, and makes a little bright circle on the
other upright. The upper hole, A, is for summer, when the sun is high,
and the lower one, B, for winter. The indicator is pivoted by a large
screw to the centre, C, of the face, so that it can be turned round like
the hand of a clock. At the upper end of the indicator a little pointer
is fastened directly over the scale of hours and minutes. A needle, or a
pin with the head cut off, makes a good pointer.

After the sun-dial is made, the next thing is to set it in its proper
position, which is so that when the pointer is at XII. it will also be
directed exactly south, while the lower end of the indicator is to the
north. Then, at noon by sun time, the sun will make its little bright
circle exactly in the middle of the lower upright. A line should be
drawn up and down to show the middle; then this line will cut the sun
circle equally in two. To find out the time before and after noon, the
indicator is moved so that the sun circle will fall on the same middle
line, and the pointer will show the time. This sun time differs somewhat
from clock time. The difference for every day in the year is given by
the almanacs, and very exactly by the Nautical Almanac. This difference
being added or subtracted, makes known the true clock time. Thus, for
the 1st of March, clock time is twelve minutes faster than sun time.
Hence noon by the sun-dial is just that much later than noon by the
clock. Any of our readers who have a little mechanical skill can make a
sun-dial, on the plan described, that, when put in proper position, will
be more reliable than the best of clocks, and that will be found a
convenient means of setting them right. But don't despise the clocks;
for very likely you will have to resort to one in order to get the
sun-d