DOI Seite / Zitierlink:
https://doi.org/10.11588/diglit.62828#0071
Operation.—Let G be the given point on the bale line GV.
Take then the * radius G O, or any other at pleafure, and turn
the arch OS. Fix again your compafs foot in O, and, without
any alteration, interfedf the arch at P. On P, with the fame open-
ing of the compaffes, make another faction at S, and from thole
points S P turn an arch each way, and their interfedtion will
form a point perpendicular with the given point G, as required.
This may alfo be effected another way with more difpatch,
but perhaps not always with equal accuracy.
Operation.—Let ME, Fig. 14, Plate *2, be the bafe, and E the
point whence you would eredt a perpendicular. With any open-
ing of the compaffes, and with one of its legs fixed any where out
of the line, as at S, fweep the arch b, d till it cut the bafe line,
as at b. Then from b draw b r through the center S, cutting
the arch at d, and their fedtion will form a point perpendicular
to E, as required.
Thefe problems maybe very ufeful to an Upholfterer when
he is laying down the plan of a room for a carpet, as it is not
convenient always to take a fquare with him. Befides, by a
good line, bradaul, and chalk, a perpendicular may be raifed
* Radius, a right line drawn from the center of a circle to its circumference. This
right line, I conceive, anfwers to the rays of light (in an optical fenfe), which, falling upon
the eye every where in right-lined directions, form a horizon to our fight.
3 with
Take then the * radius G O, or any other at pleafure, and turn
the arch OS. Fix again your compafs foot in O, and, without
any alteration, interfedf the arch at P. On P, with the fame open-
ing of the compaffes, make another faction at S, and from thole
points S P turn an arch each way, and their interfedtion will
form a point perpendicular with the given point G, as required.
This may alfo be effected another way with more difpatch,
but perhaps not always with equal accuracy.
Operation.—Let ME, Fig. 14, Plate *2, be the bafe, and E the
point whence you would eredt a perpendicular. With any open-
ing of the compaffes, and with one of its legs fixed any where out
of the line, as at S, fweep the arch b, d till it cut the bafe line,
as at b. Then from b draw b r through the center S, cutting
the arch at d, and their fedtion will form a point perpendicular
to E, as required.
Thefe problems maybe very ufeful to an Upholfterer when
he is laying down the plan of a room for a carpet, as it is not
convenient always to take a fquare with him. Befides, by a
good line, bradaul, and chalk, a perpendicular may be raifed
* Radius, a right line drawn from the center of a circle to its circumference. This
right line, I conceive, anfwers to the rays of light (in an optical fenfe), which, falling upon
the eye every where in right-lined directions, form a horizon to our fight.
3 with