A rule with four joints, each of which contained about 5 inches
9-tenths of our measure. I think there was another in two parts, which
answered to the same proportion.
II.
Philosophical transactions, Vol. L. Part I. For the year 1757. Giving some account of the present undertakings, studies, and labours, of the ingenious, in many considerable parts of the world. · 第 11 / 75 题