DOI Page / Citation link:
https://doi.org/10.11588/diglit.62828#0201
*
( I4I )
How to diminifh any Column, from the inferior to the fuperior Di-
ameter, by means of an elliptic Curve not exceeding in its Swell
the inferior Diameter.
Fig. i. Plate XIII. is Vignola’s method of diminifhing a co-
lumn, the principles of which I have taken from Sir William
Chambers’ Treatife on Architecture, but have here defcribed it
in my own way, as follows. Determine the height of the draft
as at c d, and draw a line for its axis. Next, draw b a at pleafure,
and at right angles with the axis. Let b c be half the inferior,
and nd half the fuperior diameter. Take be half the under
diameter, and with the compafles place it from n, the extreme
point of the upper diameter, to any point where it falls on the
axis of the column, as at o. From n draw a line through o,
and proceed till it cut the bafe line b a at a. Draw a line at
pleafure from b, the extreme point of the inferior diameter,
parallel with cd\ and divide this line into a number of equal
parts, as 2, 4, 6, 8, &c. From a, the center, draw a ray or
right line to each of thefe divifions, which will pafs ob-
liquely through the axis, in proportion to their diftance from
the inferior diameter be. Take then be, half the diameter,
and place it from 1 to 2, from 3 to 4, and fo on of all the reft.
Laftly, through each of thefe points draw a curve line, and the
diminution
( I4I )
How to diminifh any Column, from the inferior to the fuperior Di-
ameter, by means of an elliptic Curve not exceeding in its Swell
the inferior Diameter.
Fig. i. Plate XIII. is Vignola’s method of diminifhing a co-
lumn, the principles of which I have taken from Sir William
Chambers’ Treatife on Architecture, but have here defcribed it
in my own way, as follows. Determine the height of the draft
as at c d, and draw a line for its axis. Next, draw b a at pleafure,
and at right angles with the axis. Let b c be half the inferior,
and nd half the fuperior diameter. Take be half the under
diameter, and with the compafles place it from n, the extreme
point of the upper diameter, to any point where it falls on the
axis of the column, as at o. From n draw a line through o,
and proceed till it cut the bafe line b a at a. Draw a line at
pleafure from b, the extreme point of the inferior diameter,
parallel with cd\ and divide this line into a number of equal
parts, as 2, 4, 6, 8, &c. From a, the center, draw a ray or
right line to each of thefe divifions, which will pafs ob-
liquely through the axis, in proportion to their diftance from
the inferior diameter be. Take then be, half the diameter,
and place it from 1 to 2, from 3 to 4, and fo on of all the reft.
Laftly, through each of thefe points draw a curve line, and the
diminution