Page:The story of geographical discovery.djvu/26

 22 voyage was winding, and might possibly bring the vessel comparatively near to Byzantium, though there might be no direct road between the two cities. There was one rough way of determining how far north a place stood: the very slightest observation of the starry heavens would show a traveller that as he moved towards the north, the pole-star rose higher up in the heavens. How much higher, could be determined by the angle formed by a stick pointing to the pole-star, in relation to one held horizontally. If, instead of two sticks, we cut out a piece of metal or wood to fill up the enclosed angle, we get the earliest form of the sun-dial, known as the gnomon, and according to the shape of the gnomon the latitude of a place is determined. Accordingly, it is not surprising to find that the invention of the gnomon is also attributed to Anaximander, for without some such instrument it would have been impossible for him to have made any map worthy of the name. But it is probable that Anaximander did not so much invent as introduce the gnomon, and, indeed, Herodotus expressly states that this instrument was derived from the Babylonians, who were the earliest astronomers, so far as we know. A curious point confirms this, for the measurement of angles is by degrees, and degrees are divided into sixty seconds, just as minutes are. Now this division into sixty is certainly derived from Babylonia in the case of time measurement, and is therefore of the same origin as regards the measurement of angles.

We have no longer any copy of this first map of the world drawn up by Anaximander,