Note 64 — Chapter IV
Reading edition
It is thus that in our teaching, but by means of lines of different colours, we present the proportions reproduced in Fig. 108. Experience has demonstrated to us that this replacement of letters by conventional lines renders the proportions more easily appreciable, and that these lines, striking the eye more forcibly, then impress themselves better on the memory. Fig. 111 bears the same relation to Fig. 110.