Gravesande, Willem Jacob 's
,
An essay on perspective
Text
Text Image
Image
XML
Thumbnail overview
Document information
None
Concordance
Notes
Handwritten
Figures
Content
Thumbnails
Table of handwritten notes
<
1 - 3
[out of range]
>
<
1 - 3
[out of range]
>
page
|<
<
(65)
of 237
>
>|
<
echo
version
="
1.0RC
">
<
text
xml:lang
="
en
"
type
="
free
">
<
div
xml:id
="
echoid-div227
"
type
="
section
"
level
="
1
"
n
="
119
">
<
p
>
<
s
xml:id
="
echoid-s1563
"
xml:space
="
preserve
">
<
pb
o
="
65
"
file
="
0119
"
n
="
137
"
rhead
="
on PERSPECTIVE.
"/>
being produced, will meet each other in the
<
lb
/>
Horizontal Line.</
s
>
<
s
xml:id
="
echoid-s1564
"
xml:space
="
preserve
"/>
</
p
>
</
div
>
<
div
xml:id
="
echoid-div229
"
type
="
section
"
level
="
1
"
n
="
120
">
<
head
xml:id
="
echoid-head126
"
xml:space
="
preserve
">CHAP. V.</
head
>
<
p
style
="
it
">
<
s
xml:id
="
echoid-s1565
"
xml:space
="
preserve
">Of throwing Figures into Perſpective, when
<
lb
/>
the Perſpective Plane is conſider’d as being
<
lb
/>
inclined.</
s
>
<
s
xml:id
="
echoid-s1566
"
xml:space
="
preserve
"/>
</
p
>
</
div
>
<
div
xml:id
="
echoid-div230
"
type
="
section
"
level
="
1
"
n
="
121
">
<
head
xml:id
="
echoid-head127
"
xml:space
="
preserve
">
<
emph
style
="
sc
">Problem</
emph
>
I.</
head
>
<
p
style
="
it
">
<
s
xml:id
="
echoid-s1567
"
xml:space
="
preserve
">81. </
s
>
<
s
xml:id
="
echoid-s1568
"
xml:space
="
preserve
">TO find the Perſpective of a Figure in the
<
lb
/>
<
note
position
="
right
"
xlink:label
="
note-0119-01
"
xlink:href
="
note-0119-01a
"
xml:space
="
preserve
">Fig. 44.</
note
>
Geometrical Plane.</
s
>
<
s
xml:id
="
echoid-s1569
"
xml:space
="
preserve
"/>
</
p
>
<
p
>
<
s
xml:id
="
echoid-s1570
"
xml:space
="
preserve
">Let X be the Vertical Plane; </
s
>
<
s
xml:id
="
echoid-s1571
"
xml:space
="
preserve
">S I the Station
<
lb
/>
Line, S the Station Point, and H the Interſecti-
<
lb
/>
on of the Station Line and Baſe Line. </
s
>
<
s
xml:id
="
echoid-s1572
"
xml:space
="
preserve
">Now
<
lb
/>
draw the Vertical Line H V through the Point H,
<
lb
/>
making an Angle with S I, equal to the Angle
<
lb
/>
of Inclination of the perſpective Plane; </
s
>
<
s
xml:id
="
echoid-s1573
"
xml:space
="
preserve
">then
<
lb
/>
raiſe the Perpendicular I O to S I, in the Sta-
<
lb
/>
tion Point S, equal to the Height of the Eye;
<
lb
/>
</
s
>
<
s
xml:id
="
echoid-s1574
"
xml:space
="
preserve
">and through the Extremity of the ſaid Perpen-
<
lb
/>
dicular, draw the principal Ray O V, paral-
<
lb
/>
lel to S I, and cutting H V in the Point of
<
lb
/>
Sight V.</
s
>
<
s
xml:id
="
echoid-s1575
"
xml:space
="
preserve
"/>
</
p
>
<
p
>
<
s
xml:id
="
echoid-s1576
"
xml:space
="
preserve
">Now it is evident, that O V determines the
<
lb
/>
Length of the principal Ray, and H V the Di-
<
lb
/>
ſtance from the Baſe Line to the Horizontal
<
lb
/>
Line; </
s
>
<
s
xml:id
="
echoid-s1577
"
xml:space
="
preserve
">and ſince the Demonſtration of the
<
lb
/>
Problems in the aforegoing Chapters regarding
<
lb
/>
the Geometrical Plane, have alſo Relation to
<
lb
/>
the perſpective Plane being inclined, the ſaid
<
lb
/>
Problems may be here uſed; </
s
>
<
s
xml:id
="
echoid-s1578
"
xml:space
="
preserve
">and conſequently,
<
lb
/>
this inclined perſpective Plane is reduced to a
<
lb
/>
Perpendicular one, view’d by an Eye, whoſe
<
lb
/>
Height is H V, and Diſtance O V.</
s
>
<
s
xml:id
="
echoid-s1579
"
xml:space
="
preserve
"/>
</
p
>
</
div
>
</
text
>
</
echo
>