Note {9} — Chapter I · THE VOYAGE TO THE BRAZILS.
Reading edition
The sextant is a mathematical instrument by which the different degrees of longitude and latitude are determined, and the hour known. The chronometers also are set by it. In order to find the latitude the ship is in, an observation is taken at noon, but only when the sun shines. This last is absolutely necessary, since it is from the shadow cast upon the figures of the instrument that the reckoning is made. The longitude can be determined both morning and afternoon, as the sun, in this case, is not necessary.