[660] [This observation has been verified; for tolerably large quantities of indigo are now extracted from the _Polygonum tinctorium_, which is cultivated in some parts of France and Belgium for that purpose.] VANES. WEATHERCOCKS. If the poet Seneca was well informed, mankind, in the infancy of navigation, had no particular names for distinguishing the principal winds[661]. This is not at all incredible; because with their rafts and floats, which were the first vessels, they for a long time ventured out to sea only so far that they could easily return to the shore; and therefore while navigation continued in this state, they had little reason to trouble themselves about the direction of the winds. It is more certain that those nations respecting whom we have the oldest information, distinguished by names the four principal winds only. This is generally proved by a passage in Homer, where he intends to mention all the winds, and names only four[662]; but this proof is of little weight; for what poet at present would, with the like view, think of boxing the compass, or of introducing into a poem the names of all the thirty-two points? Would he not rather be satisfied with the names of the four chief winds alone? If more names, therefore, were usual in Homer’s time, he would not consider it necessary to name them. In another passage he names only two winds[663]; and from these some have endeavoured to prove that no more were then known; but this assertion indeed is completely refuted by the passage first quoted. It can, however, be easily proved, that for a long time names were given to the four principal winds only. It is easily seen what at first gave rise to this distinction. The sun at noon stands always over one point of the horizon, which appears to the observer as a circle, having the place where he himself is at its centre. This point is called the meridian or south, and the one opposite to it the north. If the observer turns his face towards the north, he will have on his right-hand the east, and on his left the west. The space between these principal winds contains ninety degrees, or a right angle. The number, however, must soon have been raised to eight, and this division was usual in the time of Aristotle[664]. Afterwards twelve points in the heavens were adopted, also as many winds; and in the time of Vitruvius twenty-four were distinguished and named, though this division was very little used. To determine the names, however, employed in the last two divisions is attended with some difficulties; and it almost appears as if writers did not always apply to them the same meaning.