The great Persian Empire extended from the shores of the Mediterranean right away to the east, far beyond the knowledge of the Greeks. Indeed, their knowledge of the interior of Asia was very imperfect, and Alexander's expedition was rather that of an explorer than of a conqueror. How he overthrew the Persians and subdued an area as large as Europe in the space of twelve years reads like a romance rather than fact, and it is not for us to tell the story in detail. Rather let us take up the story after Alexander has fought and conquered the Persians twice, besieged Tyre, taken the Phœnician fleet, occupied Egypt, marched across the desert and crossed the Euphrates, passed over the plain and followed the Tigris to near Nineveh, where he crossed that river too, fought another famous battle over the Persians, which decided the fate of King and Monarchy and opened to him the capitals of Babylon and Susa, wherein the immense treasures of the Persian Empire were stored. King of all Asia, he sat on the throne of the Persian kings under a golden canopy in the palace of Persepolis.

So far the whole expedition was over country known, if imperfectly, to the Greeks. Now we have to follow the conquering hero more closely as he leads us into an unknown land away to the east, known as "the farthest region of the inhabited world towards the east, beyond which lies the endless sandy desert void of inhabitants." And all the while the great land of India lay beyond, and beyond again was China, and away far over the ocean sea lay America—and they knew it not.

Alexander was a young man yet, only twenty-six. It was four years since he had left Europe, and in that short time he had done wonders. He had conquered the whole eastern half of the Persian Empire. Now he resolutely turned his face to the unknown east and started forth on an expedition of exploration.

Following the main highway from Media, which to-day leads from Teheran, capital of modern Persia, into the land of the Turkomans and the borders of Russia, he found himself between the great salt desert and the mountains, which to-day mark the frontier of Persia. Suddenly, to his great surprise, the Caspian Sea came into sight. It seemed about the same size as the Black Sea, and he concluded it was connected with the Sea of Azof; though the men of his day were certain enough that it was the most northern of four great gulfs connected with the outer ocean which flowed round the world.

Onwards towards the east he marched with his great army. To conciliate the tribes through which he passed, he adopted Persian dress. This annoyed his Greek countrymen, but, "as they admired his other virtues, they thought he might be suffered to please himself a little and enjoy his vanity."

Arrived at the modern boundary between Persia, Afghanistan, and Russia, he and his men pushed on across Afghanistan, by the caravan route that had long existed from the shores of the Caspian, by modern Herat, Kandahar, which still bears the conqueror's name, and Kabul to India. Their way lay through deep snow, deeper than they had ever seen before; and by the time they had reached the mountains of Kabul it was midwinter.

Between Alexander and India still lay the lofty range of the Hindu Koosh or Indian Caucasus. But before going south toward India, he turned northwards to explore the unknown country which lay about the river Oxus. They found the Oxus, a mighty stream, swollen with melting snows. There were no boats and no wood to build them, so Alexander pioneered his men across in "life-preservers" made out of their leather tent coverings and stuffed with straw. This river impressed the Greeks even more than the Euphrates and Tigris, as it impressed many an explorer and poet since these early days. Let us recall Matthew Arnold's famous description of the Oxus, now seen for the first time by the Greeks.

Here in this valley the Greeks met more determined opposition than they had yet encountered since entering Asia, and over two years were occupied in reducing this single district (now Bokhara and Turkestan) to submission, though it was only some three hundred and fifty miles square, and in one single year Alexander had conquered a kingdom over one thousand miles in width.

It was not till the spring of 827 that he was ready to cross the Hindu Koosh and begin the great expedition into India. The night before the start Alexander discovered that his troops were now so heavily laden with spoils that they were quite unfit for the long march. So in the early morning, when they were all ready to start, he suddenly set fire to his own baggage, and, giving orders that all his men were to do the same, the army started for the passes of the lofty mountain range. And—

The banks of the river of Kabul were reached at last. Sending part of the army by the now famous Kyber Pass toward the Indus, Alexander himself undertook to subdue the mountain tribes and get control of the Chitral passes. The shepherds of this region opposed him vigorously, but swiftly and pitilessly the King of Asia sacked their peaceful homes, and city after city fell to him as he advanced towards the boundaries of Kashmir.

At last the valley of the Indus was reached. A bridge of boats was hastily thrown over, and Alexander and his army passed to the other side.

Porus, the ruler of the country between the Indus and the river Hydaspes (Jehlam), sent presents of welcome to the invader, including three thousand animals for sacrifice, ten thousand sheep, thirty elephants, two hundred talents of silver, and seven hundred horsemen. The new king was also greeted with presents of ivory and precious stones. Even from far Kashmir came greetings to Alexander, whose fame was spreading rapidly. He now entered the Punjab, the "Land of the Five Rivers." But on the other side of the river Hydaspes a different reception awaited him.

There the king (Porus) had assembled a sturdy, well-disciplined troop to dispute the passage of the river, which separated the new King of Asia from his territory. But under cover of a mighty thunderstorm Alexander contrived to cross, though the river was rushing down yellow and fierce after the rains. Secretly the Greeks put together their thirty-oared galleys hidden in a wood, and utterly surprised Porus by landing on the other side. In their strange wanderings the Greeks had fought under varying conditions, but they had never faced elephants before. Nevertheless, they brilliantly repulsed an onslaught of these animals, who slowly retreated, "facing the foe, like ships backing water, and merely uttering a shrill, piping sound." Despite the elephants the old story was repeated, civilised arms triumphed over barbarians, and the army of Porus was annihilated, his chariots shattered, and thirty-three thousand men slain.

The kingdom beyond the Hydaspes was now Alexander's. Ordering a great fleet of rafts and boats to be built for his proposed voyage to the mouth of the Indus, he pushed on to complete the conquest of the Five Stream Land, or the Punjab—the last province of the great Persian Empire. This was India—all that was known at this time. The India of the Ganges valley was beyond the knowledge of the Western world—the Ganges itself unknown to the Persians. And Alexander saw no reason to change his mind.

"The great sea surrounds the whole earth," he stoutly maintained.

But when he reached the eastern limit of the Punjab and heard, that beyond lay a fertile land "where the inhabitants were skilled in agriculture, where there were elephants in yet greater abundance and men were superior in stature and courage," the world stretched out before him in an unexpected direction, and he longed to explore farther, to conquer new and utterly unknown worlds!

But at last his men struck. They were weary, some were wounded, some were ill; seventy days of incessant rain had taken the heart out of them.

"I am not ignorant, soldiers," said Alexander to the hesitating troops, that during the last few days the natives of this country have been spreading all sorts of rumours to work upon your fears. The Persians in this way sought to terrify you with the gates of Cilicia, with the plains of Mesopotamia, with the Tigris and Euphrates, and yet this river you crossed by a ford and that by means of a bridge. By my troth, we had long ago fled from Asia could fables have been able to scare us. We are not standing on the threshold of our enterprise, but at the very close. We have already reached the sunrise and the ocean, and unless your sloth and cowardice prevent, we shall thence return in triumph to our native land, having conquered the earth to its remotest bounds. I beseech you that ye desert not your king just at the very moment when he is approaching the limits of the inhabited world."

But the soldiers, "with their heads bent earthwards," stood in silence. It was not that they would  not follow him beyond the sunset; they could  not. Their tears began to flow, sobs reached the ears of Alexander, his anger turned to pity, and he wept with his men.

"Oh, sir," at last cried one of. his men, "we have done and suffered up to the full measure of the capacity of mortal nature. We have traversed seas and lands, and know them better than do the inhabitants themselves. We are standing now almost on the earth's utmost verge, and yet you are preparing to go in quest of an India unknown even to the Indians themselves. You would fain root out, from their hidden recesses and dens, a race of men that herd with snakes and wild beasts, so that you may traverse as a conqueror more regions than the sun surveys. But while your courage will be ever growing, our vigour is fast waning to its end. See how bloodless be our bodies, pierced with how many wounds and gashed with how many scars! Our weapons are blunt, our armour worn out! We have been driven to assume the Persian dress! Which of us has a horse? We have conquered all the world, but are ourselves destitute of all things."

The conqueror was at last conquered. The order to turn back was reluctantly given by the disappointed king and leader. It was received with shouts of joy from the mixed multitudes of his followers, and the expedition faced for home. Back they marched through the new lands where no less than two thousand cities had owned his sway, till they came to the banks of the river where the ships were building. Two thousand boats were ready, including eighty thirty-oared galleys.

It was now September 326

Nearchus from Crete was made Admiral of the new fleet, which at dawn one October morning pushed out upon the river Hydaspes and set sail downstream towards the unknown sea, Alexander standing proudly on the prow of the royal galley. The trumpets rang out, the oars moved, and the strange argosy, "such as had never been seen before in these parts," made its way down the unknown river to the unknown sea. Natives swarmed to the banks of the river to wonder at the strange sight, marvelling specially to see horses as passengers on board! The greater part of the army followed the ships on land, marching along the shores. At last the waters of the Hydaspes mingled with those of the Indus, and onwards down this great river floated the Persian fleet. Alexander had no pilots, no local knowledge of the country, but with his "unquenchable ambition to see the ocean and reach the boundaries of the world," he sailed on, "ignorant of everything on the way they had to pass." In vain they asked the natives assembled on the banks how far distant was the sea; they had never heard of the sea! At last they found a tide mixing its salt waters with the fresh. Soon a flood-tide burst upon them, forcing back the current of the river, and scattering the fleet. The sailors of the Mediterranean knew nothing of the rise and fall of tides. They were in a state of panic and consternation. Some tried to push off their ships with long poles, others tried to row against the incoming tide; prows were dashed against poops, oars were broken, sterns were bumped, until at last the sea had flowed over all the level land near the river mouth.

Suddenly a new danger appeared! The tide turned and the sea began to recede. Further misfortunes now befell the ships. Many were left high and dry; most of them were damaged in some way or another. Alexander sent horsemen to the seashore with instructions to watch for the return of the tide and to ride back in haste so that the fleet might be prepared.

Thus they got safely out to sea on the next high tide.

Alexander's explorations were now at an end. Leaving Nearchus to explore the seacoast at the mouth of the Indus, he left the spot near where the town of Hyderabad now stands, and turned his face toward the home he was never to reach. We must not linger over his terrible coast journey through the scorching desert of Beluchistan: the billows of sand, the glare of the barren sea, the awful thirst, the long hungry marches of forty miles a day under the burning Eastern sun.

Our story is one of discovery, and we must turn to Nearchus, Admiral of the fleet, left behind at the mouth of the Indus to explore the coast to the Persian Gulf, where he was to meet Alexander if possible. Shortly after the fleet had emerged from the mouth of the Indus a violent south-west monsoon began to blow and Nearchus was obliged to seek shelter in a harbour, which he called the port of Alexander, but which to-day is known as Karachi, the most western seaport of India. The waters of the Indian Ocean were quite unknown to the Greeks, and they could only coast along in sight of land, anchoring at different points for the men to land and get water and food. Past the wild barren shores of Beluchistan they made their way; the natives subsisted on fish entirely even as they do to-day—even their huts being made of fish bones and their bread of pounded fish.

They had but one adventure in their five months' cruise to the Persian Gulf, but we have a graphic account of how the terrified Greeks met a shoal of whales and how they frightened the whales away. Here is the story. One day towards daybreak they suddenly saw water spouting up from the sea, as if being violently carried upwards by whirlwinds. The sailors, feeling very frightened, asked their native guides what it meant. The natives replied that it was caused by whales blowing the water up into the air. At this explanation the Greek sailors were panic-stricken and dropped the oars from their hands. Nearchus saw that something must be done at once: So he bade the men draw up their ships in line as if for battle and row forward side by side towards the whales, shouting and splashing with their oars. At a given signal they duly advanced, and when they came near the sea-monsters they shouted with all their might and blew their trumpets and made all possible noise with their oars. On hearing which, says the old story, "the whales took fright and plunged into the depths, but not long after came to the surface again close to the sterns of the vessels and once more spouted great jets of water. Then the sailors shouted aloud at their happy and unlooked-for escape," and Nearchus was cheered as the saviour of the fleet. It is not uncommon to-day for steamers bound from Aden to Bombay to encounter what is called a "school of whales" similar to those which alarmed the fleet of Nearchus in the year 323

The expedition was completely successful and Nearchus pioneered his fleet to the mouth of the Euphrates.

But the death of Alexander the Great and the confusion that followed set back the advance of geographical discovery in this direction for some time.

Alexandria—one of the many towns founded by Alexander—had become the world centre of the learned from Europe, Asia, and Africa. Its position was unrivalled. Situated at the mouth of the Nile, it commanded the Mediterranean Sea, while by means of the Red Sea it held easy communication with India and Arabia. When Egypt had come under the sway of Alexander, he had made one of his generals ruler over that country, and men of intellect collected there to study and to write. A library was started, and a Greek, Eratosthenes, held the post of librarian at Alexandria for forty years, namely, from 240&endash;190 During this period he made a collection of all the travels and books of earth description—the first the world had ever known—and stored them in the Great Library of which he must have felt so justly proud. But Eratosthenes did more than this. He was the originator of Scientific Geography. He realised that no maps could be properly laid down till something was known of the size and shape of the earth.

By this time all men of science had ceased to believe that the world was flat; they thought of it as a perfect round, but fixed at the centre in space. Many had guessed at the size of the earth. Some said it was forty thousand miles round, but Eratosthenes was not content with guessing. He studied the length of the shadow thrown by the sun at Alexandria and compared it with that thrown by the sun at Syene, near the first cataract of the Nile, some five hundred miles distant, and, as he thought, in the same longitude. The differences in the length of these two shadows he calculated would represent one-fiftieth of the circumference of the earth, which would accordingly be twenty-thousand miles. There was no one to tell him whether he had calculated right or wrong, but we know to-day that he was wonderfully right. But he must know more. He must find out how much of this earth was habitable. To the north and south of the known countries men declared it was too hot or too cold to live. So he decided that from north to south, that is, from the land of Thule to the land of Punt (Somaliland), the habitable earth stretched for some three thousand eight hundred miles, while from east to west—that is, from the Pillars of Hercules (Straits of Gibraltar) to India—would be some eight thousand miles. All the rest was ocean. Ignoring the division of the world into three continents, he divided it into two, north and south, divided by the Mediterranean and by a long range of mountains intersecting the whole of Asia.

Then the famous librarian drew a map of the world for his library at Alexandria, but it has perished with all the rest of the valuable treasure collected in this once celebrated city. We know that he must have made a great many mistakes in drawing a map of his little island world which measured eight thousand miles by three thousand eight hundred miles. It must have been quaintly arranged. The Caspian Sea was connected with a Northern Ocean, the Danube sent a tributary to the Adriatic, there was no Bay of Biscay, the British Isles lay in the wrong direction, Africa was not half its right size, the Ganges flowed into the Eastern Ocean, Ceylon was a huge island stretching east and west, while across the whole of Asia a mountain chain stretched in one long unbroken line. And yet, with all his errors, he was nearer the truth than men three centuries later.