DOI Seite / Zitierlink:
https://doi.org/10.11588/diglit.62828#0116
( 64 )
any convenient number of equal parts. From thefe diviiions
(fuppofe four) raife perpendicular lines to the Periphery- or
circumference, which are called the Ordinates of that circle.
Obferve, the diameter of this circle is always equal to the con-
jugate diameter of the oval.—Proceed now to draw a line on
the fuppofed fmooth fur face, on which to determine the length
of the long diameter; which divide into the fame number of
equal parts from the center each way as the femi-diameter of
the circle is divided into. From thefe diviiions draw lines acrofs,
as the figure ihews. Number the ordinates of the circle, as
i, 2, 3, 4, and do the fame to thofe of the intended oval. Take
then the compaifes, and fixing one foot in i on the circle, ex-
tend the other to the point where that line touches the circum-
ference. Transfer this opening of the compaifes to the lines
1.1 for the oval, and make a pencil mark at the point each way
from the diameter. Take the ordinate 2 from the circle, and
place it each way from the diameter on the ordinates 2.2 for
the oval, and mark the points with a pencil as before. In this
way proceed till all the ordinate lines are taken from the circle
and transferred to their correfponding ordinates for the oval;
after which nothing will remain but to draw a fmooth curved
line through each point, and the oval will be complete.
* Periphery, from peri, about, and pbcro, I bear or carry; which derivation,
if I am not miftaken, alludes to the hand bearing the radius about its center, in order to
dvfcribe the circumference of the circle.
Prob
any convenient number of equal parts. From thefe diviiions
(fuppofe four) raife perpendicular lines to the Periphery- or
circumference, which are called the Ordinates of that circle.
Obferve, the diameter of this circle is always equal to the con-
jugate diameter of the oval.—Proceed now to draw a line on
the fuppofed fmooth fur face, on which to determine the length
of the long diameter; which divide into the fame number of
equal parts from the center each way as the femi-diameter of
the circle is divided into. From thefe diviiions draw lines acrofs,
as the figure ihews. Number the ordinates of the circle, as
i, 2, 3, 4, and do the fame to thofe of the intended oval. Take
then the compaifes, and fixing one foot in i on the circle, ex-
tend the other to the point where that line touches the circum-
ference. Transfer this opening of the compaifes to the lines
1.1 for the oval, and make a pencil mark at the point each way
from the diameter. Take the ordinate 2 from the circle, and
place it each way from the diameter on the ordinates 2.2 for
the oval, and mark the points with a pencil as before. In this
way proceed till all the ordinate lines are taken from the circle
and transferred to their correfponding ordinates for the oval;
after which nothing will remain but to draw a fmooth curved
line through each point, and the oval will be complete.
* Periphery, from peri, about, and pbcro, I bear or carry; which derivation,
if I am not miftaken, alludes to the hand bearing the radius about its center, in order to
dvfcribe the circumference of the circle.
Prob