Thompson's school days, however, were now to be cut short. By the 20th of May, 1784, the formalities were completed by which he was bound apprentice to the Hudson's Bay Company for seven years; and he at once embarked from the Port of London on the Company's ship, Prince Rupert, en route for North America. The lines were cast off, and the vessel with its cargo of goods for the Indian trade drifted lazily down stream with the tide, carrying Thompson away for ever from the sights and sounds of London, which he knew and loved so well.

The voyage was uneventful, except for the usual incidents that attended the westward journey of the Company's annual fleet. Not a detail, however, escaped the keen eye of the young traveller, unaccustomed as he was to anything but the quiet life of the school, and thirsting to see something of the world, which he knew only in the pages of Gulliver and Robinson Crusoe. The ship sailed up the North Sea to Stromness in the Orkneys, there to wait three weeks for the two vessels which were to accompany her across the Atlantic, and to receive final instructions and sailing orders. As they lay in the harbour of Stromness, Thompson's keen eyes noted the strange life of the kelp-burners on shore, men, women, and children who, half-naked, gathered the dripping sea-weed in baskets, and lugged it on their shoulders to the kilns. Gazing at the rocky shore line and the low, dark cottages with their smoky peat fires, which dotted the barren hills, he was smitten with regret for the rich meadows and woods of England, and for a moment he wished himself back amid the scenes of his school life. Yet in his rambles ashore, the lad found much to interest him. He observed with amusement the quaint habits of the cottagers, who combined a brisk trade in smuggled liquor with lengthy and solemn weekly devotions at the old-fashioned Kirk by the shores of the harbour.

Sailing orders finally arrived from London, and the little fleet was soon off on its hazardous journey across the stormy North Atlantic. Presently the sight of icebergs drifting south with the Arctic current, warned the crews that they were nearing Hudson Straits. It was a month before they had worked their way through the floating ice of the Straits; after which the three ships separated, one for the factories at Moose and Albany rivers, the second for York, while the Prince Rupert, with Thompson aboard, headed for Churchill, the most northerly of the Company's settlements on the west side of the Bay. Before long, they sighted the granite coast, which they followed southward. This ended at Churchill in a low point of rock and sand, surmounted by the grim stone battlements of Fort Prince of Wales, which two years before had been gutted by the French in their raid on the Bay. Rounding this point, they found themselves in the mouth of the Churchill, a noble stream, almost a mile in breadth. Up the river they made their way for a distance of five miles to a small bay at the head of the estuary, where they cast anchor before the log huts of the still unfinished new fort.

The arrival of the annual ship was the event of the year. Hurried preparations were made for discharging the cargo of provisions for the factory and supplies for the Indian trade, and taking on board the year's accumulation of furs, which were destined to adorn the persons of the fashionable world of England and the Continent. In the midst of this confusion, the new apprentice was taken ashore, and within ten days the Prince Rupert sailed away, leaving him to face the rigours of his new life on the dismal shores of Hudson Bay.

It was indeed a new life in which David Thompson found himself. Apart from the officers, there was a staff of sixty artisans and servants in the fort. These were all busy from dawn till dark; for, besides conducting their trade with the Indians, they had to maintain themselves as a community in an utterly barren land. At six each morning in summer, and eight in winter, the duty bell summoned to their toil, accountant, steward, armourer, shipwright, carpenter, cooper, blacksmith, mason, tailor, and labourers. Assisted by his officers, the governor, gorgeous in scarlet tunic and ruffles, his sword and pistols in his belt, supervised the labours of the factory.

By the early part of October, the myriads of wild geese and ducks which each summer lived in the vast swamps to the south of Churchill had winged their way to warmer climes. The middle of the month saw the marshes stiff with frost, and snow lying on the ground. The polar bear made his appearance, waiting for the ice to extend some distance from the shore, when he left to prey on the seal, his favourite food. By the fifteenth of November, the broad and deep river was frozen solid from bank to bank, not to break up until the middle of June in the following year. Till the end of December, the staff were able to keep the yard of the fort clear of snow. At that time, a three days' blow from the north-east filled the fort with snow to a depth of six feet, with drifts as high as the stockades. Thereafter it was enough if they could keep paths cleared from one hut to another.

The cold was intense. The noise of rocks split by the frost broke the silence of the night with a sound like that of a cannon shot. On the interior walls of the still unfurnished huts, the rime collected to a depth of four inches, and on this the shivering inhabitants threw pails of water in order that it might form a coat of ice to increase the warmth of the houses. Owing to the haste with which the huts had been thrown up, there had been no time to lay in a sufficient supply of firewood for the winter; and all the wood that could be gathered for fuel allowed only one fire in the morning and one in the evening. During the rest of the day, if the weather was bad, Thompson, with the others, had to pace the guard room floor, muffled to the eyes in his beaver coat, in order to keep himself from freezing. On clear days, however, he passed his time in shooting grouse, and this activity he enjoyed except for the tumbles in the snow and the sore feet and ankles that resulted from his eager efforts to walk in snow-shoes.

The dreary winter seemed endless, when, in the middle of June, summer burst with the suddenness of dawn in the Tropics, bringing with it torments which made Thompson regret even the discomforts of winter. "Hudson Bay," he says in his narrative, "is certainly a country which Sinbad the sailor never saw, for he makes no mention of musketoes." These pests rose from the marshes in clouds, driving man and beast to distraction. The dogs in the fort howled in their agony, rolling themselves on the ground and hiding in the pools. Even the fox was in a fighting humour, barking and snapping; and, hungry though he was, he was forced to seek shelter in his hole.

Such was Thompson's first year on the Bay. He had expected, when he reached the Fort, to be employed as a clerk, but he soon found that his only business was to amuse himself, "in winter growling at the cold, and in the open season shooting gulls, duck, and plover and quarreling with musketoes and sand flies." Fortunately, however, he had for company three of the officers of the factory, the deputy governor, the sloop-master, and the surgeon. To these gentlemen he felt himself greatly indebted for the loan of various books on history and natural science, by reading which he was able to put his hours of idleness to profitable use.

The governor at that time was Samuel Hearne, a handsome giant with a rubicund face. It was Hearne who in 1782 had surrendered without a blow the great stone fort at the mouth of the river. That fort had cost the Company forty years to build, and it was barely completed when Hearne raised the white flag at the challenge of the French admiral, La Pérouse. To the mind of young Thompson, this act was enough to stamp the governor as a coward. It was, none the less, the same Hearne who had succeeded in penetrating as far North as the mouth of the Coppermine river, and was thus the first white man to reach the margin of the Arctic ocean. Nevertheless, Thompson disliked him. Like so many others at the close of the eighteenth century, Hearne was infected with the doctrines of Voltaire, and his atheism shocked the sensitive mind of the pious boy. To a lad of Thompson's ambition, the life of a hunter afforded no sort of satisfaction, and he dreaded lest he should succumb to the deadening influence of his surroundings. He complained to Hearne that his lack of clerical employment might lead to the loss of his penmanship, and was barely satisfied when the governor handed him an invoice or two to copy, and gave him occupation for a few days upon the manuscript of his Journey to the North.