Through Asia. E-book. Formato PDF Sven Anders Hedin   -  Forgotten Books, 2017  - 

In making these measurements I used only a compass and a base-line. The latter varied from 200 (656 feet) to 400 (1312% feet) metres, and was in every case accurately measured with the metre-measure. After measuring my base-line, I carefully noted the time it took the caravan, properly laden and travelling at its ordinary average pace, to traverse it from the one end to' the other; at the same time I was scrupulous to make all due allowance for the inclination of the ground and other inequalities of the surface.