402 Descripition and Use of 
stance. This scale has degrees on one side of the surface, 
and inches and parts of inches on the other. 
Directions for using the Sectograph. 
The letters and figures referred to in the following die 
rections are marked on the instrument. 
Open the instrument by pulling A and B asunder, until 
the exterior nearly forms a square. Hold it im the hand, 
or place it on paper, with A next to you: the points will 
then appear in line, and numbered from left to right 0, 2, 45 
&c. and may be made to recede from or advance to each 
other at pleasure. For dividing lines, place @ on the he- 
ginning, and the 2d, 3d, 4th, &c. on the other point or 
distance to be divided, and press down the intermediate 
points, or as many as may be required. When a transfer 
or copy is to be taken, take care to clamp the instrument 
by the milled head as soon as it is set. For measuring 
distances, place 0 on one point, and the point of the op- 
posite corner on the other: the scale on the side where the 
divisions are marked 1, 2, 3, 4, &c. (indicating inches) will 
give, at the clamp, the inches and parts of the required di- 
stance. For Jaying down angles, (the other side of the 
scalé marked 10, 20, 30, &c. are the degrees, the point A 
the angular point, and the other two points 0 and 8 form 
with A the sides of the angle,) set the division of the clamp 
to the number of degrees, clamp the instrument, and apply 
the points to the paper, or other surface. For measuring 
angles, place the point A in the angle, and the other points 
to the sides respectively, clainp the instrument, and the 
scale will give the number of degrees. For angles of one 
degree, &c. set the instrument to ninety degrees, and clamp: 
it; then place A, 8, on one side of the angle and let fall the 
point O, press gently the points A and 0, loosen the clamp, 
hft the point 8, and move the required number of degrees, 
either for measuring or laying down angles. By tse scale 
of inches the points are placed one inch, one-half, one- 
quarter, one-eighth, or one-sixteenth, from each other. 
The intermediate distances may be had by the scale of iaches, 
In order to get the hundredth part of an inch, set the clamp 
to 5 inches, beyond which are ten divisions; then place the 
7th point in the dot where you want the hundreds to com- 
mence ; let fall the 8th point, on which place the second 
finger of the right hand firmly; with the other hand hold 
the end 0, letting the fingers touch the paper; them raise 
the 7th point, still keeping the sth down, and move the 
points towards cach other until you come to the first of the’ 
ten 
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