DOI Seite / Zitierlink:
https://doi.org/10.11588/diglit.19572#0022
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The preceding Rule exemplified in Objects beneath the Horizon. See Fig. XIL
Plate IV.
Having ruled the Horizontal Line A B, fix the Point of Sight as at C ; then,,
according to your Judgment, make a Dot for the Feet of your Figure as at D, and
another for the Head as at K ; then rule a Line from C to D, and from C to E, and
thefe two Diagonals will (hew the true Height of any Number of Figures that can
be wanted. Make Dots for the Place of the Feet of any Figure where you would
have them fraud, as at F, G, H, I, and K : now to know the Height of each reflec-
tively, draw parallel Lines from the Dots F, G, H, I, and K, to the Diagonal C D;
then raife Perpendiculars from the Points where the Parallels interfecl this Diagonal
at L Q_, M R, N S, O T, and P U, and the Perpendicular L Q_fhews the Height
of the Figure at F, as does M R of that at G, N S of that at H, OT of that at fr
and P U of that at K.
Note, You will be obliged always to fix the Height of one Figure as at D E, in.
order to find the Size of the reft ; and the Point cf Sight may be placed at any JJif-
tance you pleafe from the firft fuppofed Figure on the Horizontal Line.
From a Line given to form a Square. See Fig. XIII. Plate IV.
Rule your Bafe Line of any Length you pleafe, as at A B ; then raife Perpendi-
culars (as in Fig. II.) from A to C, and from B to D ; next take with your Com-
pares the Length from A to B, and, fetting one Foot in A, turn the Arch E F ; then
with the fame Extent of Compafles fet one Foot in B, and' defcribe the Arch G H;
Iaftly, rule a Line from I to K, touching the outward Parts of the two Arches where
they interfecf. the Perpendiculars, and you have the Square required.
From a given Line to form a Parallelogram. See Fig. XIV. Phte IV.
Rule a given Line of the Length required, as at A B ; then raife a Perpendicular
at A, and another at B, (as in Fig. II.) and on them fet ofT the proper Heights, as
A C and B D; join C D with a Line, and your Parallelogram is complete.
F I G. XV. Plate IV.
In this Figure we have attempted to fhew how to drawr with Certaintv, that Curved
Line, which Mr. Hogarth, in his ingenious /Inalyfis, has ftiled the Line of Beauty*-
There has, however, been an Objection nifed by fome, that he has omitted the Rule
whereby this truly ujeful Line may be found : For which Reafon, and in order to
enforce the Study of it, we have given chis Figure, not as an Infult upon that celebrated
Author (whofe Meaning is very clear), but as a Line well deferving of Attention-,
being of itfelf fingle and eafily drawn ; and as we are defirous of following the
Method of that great Artift, in the Explanation of our Ideas by the molt familiar
Obje&s, we here inform the Student, that it may be plainly feen in that well-known
Amufement of the School-Boy, a iix-pointed Star; in which the contrafted Halves
cf any two oppoiite Points give the Line which is with great Propriety (tiled ib*
Lint of Beauty.
To
The preceding Rule exemplified in Objects beneath the Horizon. See Fig. XIL
Plate IV.
Having ruled the Horizontal Line A B, fix the Point of Sight as at C ; then,,
according to your Judgment, make a Dot for the Feet of your Figure as at D, and
another for the Head as at K ; then rule a Line from C to D, and from C to E, and
thefe two Diagonals will (hew the true Height of any Number of Figures that can
be wanted. Make Dots for the Place of the Feet of any Figure where you would
have them fraud, as at F, G, H, I, and K : now to know the Height of each reflec-
tively, draw parallel Lines from the Dots F, G, H, I, and K, to the Diagonal C D;
then raife Perpendiculars from the Points where the Parallels interfecl this Diagonal
at L Q_, M R, N S, O T, and P U, and the Perpendicular L Q_fhews the Height
of the Figure at F, as does M R of that at G, N S of that at H, OT of that at fr
and P U of that at K.
Note, You will be obliged always to fix the Height of one Figure as at D E, in.
order to find the Size of the reft ; and the Point cf Sight may be placed at any JJif-
tance you pleafe from the firft fuppofed Figure on the Horizontal Line.
From a Line given to form a Square. See Fig. XIII. Plate IV.
Rule your Bafe Line of any Length you pleafe, as at A B ; then raife Perpendi-
culars (as in Fig. II.) from A to C, and from B to D ; next take with your Com-
pares the Length from A to B, and, fetting one Foot in A, turn the Arch E F ; then
with the fame Extent of Compafles fet one Foot in B, and' defcribe the Arch G H;
Iaftly, rule a Line from I to K, touching the outward Parts of the two Arches where
they interfecf. the Perpendiculars, and you have the Square required.
From a given Line to form a Parallelogram. See Fig. XIV. Phte IV.
Rule a given Line of the Length required, as at A B ; then raife a Perpendicular
at A, and another at B, (as in Fig. II.) and on them fet ofT the proper Heights, as
A C and B D; join C D with a Line, and your Parallelogram is complete.
F I G. XV. Plate IV.
In this Figure we have attempted to fhew how to drawr with Certaintv, that Curved
Line, which Mr. Hogarth, in his ingenious /Inalyfis, has ftiled the Line of Beauty*-
There has, however, been an Objection nifed by fome, that he has omitted the Rule
whereby this truly ujeful Line may be found : For which Reafon, and in order to
enforce the Study of it, we have given chis Figure, not as an Infult upon that celebrated
Author (whofe Meaning is very clear), but as a Line well deferving of Attention-,
being of itfelf fingle and eafily drawn ; and as we are defirous of following the
Method of that great Artift, in the Explanation of our Ideas by the molt familiar
Obje&s, we here inform the Student, that it may be plainly feen in that well-known
Amufement of the School-Boy, a iix-pointed Star; in which the contrafted Halves
cf any two oppoiite Points give the Line which is with great Propriety (tiled ib*
Lint of Beauty.
To