DOI Seite / Zitierlink:
https://doi.org/10.11588/diglit.62828#0335
( =55 )
Prob. XIV. Fig. 15. Plate XVIII.
To find the Repref ent ation of a Number of Squares when the Dif
tance is out of the Limits of the PiHure.
The double lines which include the fquares, are the boun-
daries of the paper, board, or picture wedraw on.
Operation.—Let r be the center, and kt r d be fuppofed half
the length of the point of diftance. Make then a fcale on the
ground line, whofe equal parts fhall be equal to half the fide of
the fquares to be reprefented, as 3,4, 5.. Lay on from 3 to 4
half the fide of the fquare A, and from 4 draw a line to d, half
the diftance, which will cut the vifual 3 r in the fame point as
it would have been cut if d had been twice its prefent diftance
from j, and the whole fide of the fquare had been laid on the
ground line, as at 5; for it is evident, that a line from 5 through
t would terminate in a point on the horizon twice the diftance
of r d. From 4 lay on 5, 6, equal 3, 4, and drawing lines to d,
we fhall have the fquares B C. Here the learner muft obferve
another difficulty arifing; for the ground line of the picture is
filled up at 6, and we are fuppofed to want the reprefentation
of three more fquares; and as the point 6 is near the extremities
of
Prob. XIV. Fig. 15. Plate XVIII.
To find the Repref ent ation of a Number of Squares when the Dif
tance is out of the Limits of the PiHure.
The double lines which include the fquares, are the boun-
daries of the paper, board, or picture wedraw on.
Operation.—Let r be the center, and kt r d be fuppofed half
the length of the point of diftance. Make then a fcale on the
ground line, whofe equal parts fhall be equal to half the fide of
the fquares to be reprefented, as 3,4, 5.. Lay on from 3 to 4
half the fide of the fquare A, and from 4 draw a line to d, half
the diftance, which will cut the vifual 3 r in the fame point as
it would have been cut if d had been twice its prefent diftance
from j, and the whole fide of the fquare had been laid on the
ground line, as at 5; for it is evident, that a line from 5 through
t would terminate in a point on the horizon twice the diftance
of r d. From 4 lay on 5, 6, equal 3, 4, and drawing lines to d,
we fhall have the fquares B C. Here the learner muft obferve
another difficulty arifing; for the ground line of the picture is
filled up at 6, and we are fuppofed to want the reprefentation
of three more fquares; and as the point 6 is near the extremities
of