Concept
Diameter
Overview
straight line segment that passes through the center of a circle; its length
Overview adapted from Wikipedia (CC BY-SA 4.0; see the article history for authors).
Possible passages
Found by search and not yet checked by a person; they may only mention the idea in passing.
The diagrams generally approach in form to a succession of more or less irregular ellipses or ovals, with their longer axes directed to different points of the compass during the same day or on succeeding days. The stems therefore, sooner or later, bend to all sides; but after a stem has bent in any one direction, it commonly bends back at first in nearly, though not quite, the opposite direction; and this gives the…
Charles Darwin, The Power of Movement in Plants
Close in meaning to Diameter; the term itself is not named.
To make this clear, some illustration will be necessary. Suppose we take an orange, and, assuming the marks of the stalk and the calyx to represent the poles, cut off round the line of the equator a strip of peel. This strip of peel, if placed on the table with its ends meeting, will make a ring shaped like the hoop of a barrel--a ring of which the thickness in the line of its diameter is very small, but of which…
Herbert Spencer, Essays
Names Diameter several times; states what Diameter is.
The manner in which a full-grown shell assumes its ordinary shape, at first appears very perplexing:[129] it has to change from a cylinder, at first probably not much above the 1/50th of an inch in diameter, to a cylinder nearly one inch in diameter: and this is not effected by the growth of the radii, for the radii never reach the basis, and the basis of course has to increase in diameter like the rest of the…
Charles Darwin, A Monograph on the Sub-class Cirripedia
Names Diameter several times; opens on Diameter.
Related ideas
Place in the tradition
Part of Pre-Socratic philosophy.