DOI Page / Citation link:
https://doi.org/10.11588/diglit.62828#0082
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On the Sector*.
The SecStor is a moft univerfal inftrument, and ufed for
various purpofes in the different branches of mathematical
learning. Nor is it without its ufefulnefs in the art of drawing,
and therefore thofe who are concerned wTith defigning ought,
in fome meafure, to be acquainted with it.
To this end let us firft confider the moft flmple part of it,
which is, to divide any given right line into any number of
equal parts.
The line to be divided by the feftor is 7.7, Plate I. Fig. 5,
w hich is to be divided into feven.
Firft, Look for the line of lines on the fedor, which may
be found by obferving two brafs centers marked with l on
each limb of the inftrument.
Second, Take the length of the line 7.7 in your compares,
and place one foot on the point 7 on the line of lines, and open-
ing the fecftor, extend it till the other leg of the compares co-
* Sector; it is fo called becaufe, when it is opened, it comprehends a portion of a
.circle between two femidiameters, making an angle at the center, as O A 4, Plate I. Fig. 6.
incides
On the Sector*.
The SecStor is a moft univerfal inftrument, and ufed for
various purpofes in the different branches of mathematical
learning. Nor is it without its ufefulnefs in the art of drawing,
and therefore thofe who are concerned wTith defigning ought,
in fome meafure, to be acquainted with it.
To this end let us firft confider the moft flmple part of it,
which is, to divide any given right line into any number of
equal parts.
The line to be divided by the feftor is 7.7, Plate I. Fig. 5,
w hich is to be divided into feven.
Firft, Look for the line of lines on the fedor, which may
be found by obferving two brafs centers marked with l on
each limb of the inftrument.
Second, Take the length of the line 7.7 in your compares,
and place one foot on the point 7 on the line of lines, and open-
ing the fecftor, extend it till the other leg of the compares co-
* Sector; it is fo called becaufe, when it is opened, it comprehends a portion of a
.circle between two femidiameters, making an angle at the center, as O A 4, Plate I. Fig. 6.
incides