class="x-ebookmaker-pageno" title="Page 33" id="pgepubid00048"/> reckoning eastward, and would not have resulted in any serious distortion of the truth; but instead of this, he adopted as his point of departure the Fortunatæ Insulæ, or Canary Islands, and every degree measured to the east of these was one-fifth too great, since he assumed that it was only fifty miles in length. I may mention that so great has been the influence of Ptolemy on geography, that, up to the middle of the last century, Ferro, in the Canary Islands, was still retained as the zero-point of the meridians of longitude.

Another point in which Ptolemy's system strongly influenced modern opinion was his departure from the previous assumption that the world was surrounded by the ocean, derived from Homer. Instead of Africa being thus cut through the middle by the ocean, Ptolemy assumed, possibly from vague traditional knowledge, that Africa extended an unknown length to the south, and joined on to an equally unknown continent far to the east, which, in the Latinised versions of his astronomical work, was termed "terra australis incognita," or "the unknown south land." As, by his error with regard to the breadth of the earth, Ptolemy led to Columbus; so, by his mistaken notions as to the "great south land," he prepared the way for the discoveries of Captain Cook. But notwithstanding these errors, which were due partly to the roughness of the materials which he had to deal with, and partly to scientific caution, Ptolemy's work is one of the great monuments of human industry and knowledge. For the Old World it remained the basis of all geographical knowledge up to the beginning of the last century, just as his astronomical work was only finally abolished by the work of Newton. Ptolemy has thus the rare distinction of being the greatest authority on two important departments of human knowledge—astronomy and geography—for over fifteen hundred years. Into the details of his description of the world it is unnecessary to go. The map will indicate how near he came to the main outlines of the Mediterranean, of Northwest Europe, of Arabia, and of the Black Sea. Beyond these regions he could only depend upon the rough indications and guesses of untutored merchants. But it is worth while referring to his method of determining latitude, as it was followed up by most succeeding geographers. Between the equator and the most northerly point known to him, he divides up the earth into horizontal strips, called by him "climates," and determined by the average length of the longest day in each. This is a very rough method of determining latitude, but it was probably, in most cases, all that Ptolemy had to depend upon, since the measurement of angles would be a rare accomplishment even in modern times, and would only exist among a few mathematicians and astronomers in Ptolemy's days. With him the history of geographical knowledge and discovery in the ancient world closes.

In this chapter I have roughly given the names and exploits of the Greek men of science, who summed up in a series of systematic records the knowledge obtained by merchants, by soldiers, and by travellers of the extent of the world known to the ancients. Of this knowledge, by far the largest amount was gained, not by systematic investigation for the purpose of geography, but by military expeditions for the purpose of conquest. We must now retrace our steps, and give a rough review of the various stages of conquest. We must now retrace our steps, and give a rough review of the various stages of conquest by which the different regions of the Old World became known to the Greeks and the Roman Empire, whose knowledge Ptolemy summarises.

[Authorities: Bunbury, History of Ancient Geography, 2 vols., 1879; Tozer, History of Ancient Geography, 1897.]

CHAPTER II

THE SPREAD OF CONQUEST IN THE ANCIENT WORLD

In a companion volume of this series, "The Story of Extinct Civilisations in the East," will be found an account of the rise and development of the various nations who held sway over the west of Asia at the dawn of history. Modern discoveries of remarkable interest have enabled us to learn the condition of men in Asia Minor as early as 4000 B.C. All these early civilisations existed on the banks of great rivers, which rendered the land fertile through which they passed.

We first find man conscious of himself, and putting his knowledge on record, along the banks of the great rivers Nile, Euphrates, and Tigris, Ganges and Yang-tse-Kiang. But for our purposes we are not concerned with these very early stages of history. The Egyptians got to know something of the nations that surrounded them, and so did the Assyrians. A summary of similar knowledge is contained in the list of tribes given in the tenth chapter of Genesis, which divides all mankind, as then known to the Hebrews, into descendants of Shem, Ham, and Japhet—corresponding, roughly, to Asia, Europe, and Africa. But in order to ascertain how the Romans obtained the mass of information which was summarised for them by Ptolemy in his great work, we have merely to concentrate our attention on the remarkable process of continuous expansion which ultimately led to the existence of the Roman Empire.

All early histories of kingdoms are practically of the same type. A certain tract of country is divided up among a certain number of tribes speaking a common language, and each of these tribes ruled by a separate chieftain. One of these tribes then becomes predominant over the rest, through the skill in war or diplomacy of one of its chiefs, and the whole of the tract of country is thus organised into one kingdom. Thus the history of England relates how the kingdom of Wessex grew into predominance over the whole of the country; that of France tells how the kings who ruled over the Isle of France spread their rule over the rest of the land; the history of Israel is mainly an account of how the tribe of Judah obtained the hegemony of the rest of the tribes; and Roman history, as its name implies, informs us how the inhabitants of a single city grew to be the masters of the whole known world. But their empire had been prepared for them by a long series of similar expansions, which might be described as the successive swallowing up of empire after empire, each becoming overgrown in the process, till at last the series was concluded by the Romans swallowing up the whole. It was this gradual spread of dominion which, at each stage, increased men's knowledge of surrounding nations, and it therefore comes within our province to roughly sum up these stages, as part of the story of geographical discovery.

Regarded from the point of view of geography, this spread of man's knowledge might be compared to the growth of a huge oyster-shell, and, from that point of view, we have to take the north of the Persian Gulf as the apex of the shell, and begin with the Babylonian Empire. We first have the kingdom of Babylon—which, in the early stages, might be best termed Chaldæa—in the south of Mesopotamia (or the valley between the two rivers, Tigris and Euphrates), which, during the third and second millennia before our era, spread along the valley of the Tigris. But in the fourteenth century B.C., the Assyrians to the north of it, though previously dependent upon Babylon, conquered it, and, after various vicissitudes, established themselves throughout the whole of Mesopotamia and much of the surrounding lands. In 604 B.C. the capital of this great empire was moved once more to Babylon, so that in