Sergeant Long hastened to the narrow passage from which opened the outer door of the fort, and heard the cries redoubled, and combined with violent blows on the postern gate, surrounded by high walls, which gave access to the court. The Sergeant pushed open the door, and plunging into the snow, already a foot deep; he waded through it, although half-blinded by the cutting sleet, and nipped by the terrible cold.

“What the devil does any one want at this time of night?” exclaimed the Sergeant to himself, as he mechanically removed the heavy bars of the gate; “none but Esquimaux would dare to brave such a temperature as this!”

“Open! open! open!” they shouted from without.

“I am opening,” replied Sergeant Long, who really seemed to be a long time about it.

At last the door swung open, and the Sergeant was almost upset by a sledge, drawn by six dogs, which dashed past him like a flash of lightning. Worthy Sergeant Long only just escaped being crushed, but he got up without a murmur, closed the gate, and returned to the house at his ordinary pace, that is to say, at the rate of seventy-five strides a minute.

But Captain Craventy, Lieutenant Jaspar Hobson, and Corporal Joliffe were already outside, braving the intense cold, and staring at the sledge, white with snow, which had just drawn up in front of them.

A man completely enveloped in furs now descended from it,

“Fort Reliance?;” he inquired.

“The same,” replied the Captain.

“Captain Craventy?”

“Behold him! Who are you?”

“A courier of the Company.”

“Are you alone?”

“No, I bring a traveller.”

“A traveller! And what does he want?”

“He is come to see the moon.”

At this reply, Captain Craventy said to himself the man must be a fool. But there was no time to announce this opinion, for the courier had taken an inert mass from the sledge, a kind of bag covered with snow, and was about to carry it into the house, when the Captain inquired

“What is that bag?”

“It is my traveller,” replied the courier.

“Who is this traveller?”

“The astronomer, Thomas Black.”

“But he is frozen.”

“Well, he must be thawed.”

Thomas Black, carried by the Sergeant, the Corporal, and the courier, now made his entrance into the house of the fort, and was taken to a room on the first floor, the temperature of which was bearable, thanks to a glowing stove. He was laid upon a bed, and the Captain took his hand.

It was literally frozen. The wrappers and furred mantles, in which Thomas Black was rolled up like a parcel requiring care, were removed, and revealed a man of about fifty. He was short and stout, his hair was already touched with grey, his beard was untrimmed, his eyes were closed, and his lips pressed together as if glued to one another. If he breathed at all, it was so slightly that the frost-work on the windows would not have been affected by it. Joliffe undressed him, and turned him rapidly on to his face and back again, with the words —

“Come, come, sir, when do you mean to return to consciousness?”

But the visitor who had arrived in so strange a manner showed no signs of returning life, and Corporal Joliffe could think of no better means to restore the lost vital heat than to give him a bath in the bowl of hot punch.

Very happily for Thomas Black, however, Lieutenant Jaspar Hobson had another idea.

“Snow, bring snow!” he cried.

There was plenty of it in the court of Fort Reliance; and whilst the Sergeant went to fetch the snow, Joliffe removed all the astronomer’s clothes. The body of the unfortunate man was covered with white frost-bitten patches. It was urgently necessary to restore the circulation of the blood in the affected portions. This result Jaspar Hobson hoped to obtain by vigorous friction with the snow. We know that this is the means generally employed in the polar countries to set going afresh the circulation of the blood arrested by the intense cold, even as the rivers are arrested in their courses by the icy touch of winter. Sergeant Loin soon returned, and he and Joliffe gave the new arrival such a rubbing as he had probably never before received. It was no soft and agreeable friction, but a vigorous shampooing most lustily performed, more like the scratching of a curry-comb than the caresses of a human hand.

And during the operation the loquacious Corporal continued to exhort the unconscious traveller.

“Come, come, sir. What do you mean by getting frozen like this. Now, don’t be so obstinate!”

Probably it was obstinacy which kept Thomas Black from deigning to show a sign of life. At the end of half an hour the rubbers began to despair, and were about to discontinue their exhausting efforts, when the poor man sighed several times.

“He lives; he is coming to!” cried Jaspar Hobson.

After having warmed the outside of his body, Corporal Joliffe hurried to do the same for the inside, and hastily fetched a few glasses of the punch. The traveller really felt much revived by them; the colour returned to his cheeks, expression to his eyes, and words to his lips, so that Captain Craventy began to hope that he should have an explanation from Thomas Black himself of his strange arrival at the fort in such a terrible condition.

At last the traveller, well covered with wraps, rose on his elbow, and said in a voice still faint

“Fort Reliance?”

“The same,” replied the Captain.

“Captain Craventy?”

“He is before you, and is happy to bid you welcome. But may I inquire what brings you to Fort Reliance?”

“He is come to see the moon,” replied the courier, who evidently thought this a happy answer.

It satisfied Thomas Black too, for he bent his head in assent and resumed —

“Lieutenant Hobson?”

“I am here,” replied the Lieutenant.

“You have not yet started?”

“Not. yet, sir.”

“Then,” replied Thomas Black, “I have only to thank you, and to go to sleep until to-morrow morning.”

The Captain and his companions retired, leaving their strange visitor to his repose. Half an hour later the fête was at an end, and the guests had regained their respective homes, either in the different rooms of the fort, or the scattered houses outside the enceinte.

The next day Thomas Black was rather better. His vigorous constitution had thrown off the effects of the terrible chill he had had. Any one else would have died from it; but he was not like other men.

And now who was this astronomer? Where did he come from? Why had he undertaken this journey across the territories of the Company in the depth of winter? What did the courier’s reply signify?— To see the moon! The moon could be seen anywhere; there was no need to come to the hyperborean regions to look at it!

Such were the thoughts which passed through Captain Craventy’s mind. But the next day, after an hour’s talk with his new guest, he had learned all he wished to know.

Thomas Black was an astronomer attached to the Greenwich Observatory, so brilliantly presided over by Professor Airy. Mr Black was no theorist, but a sagacious and intelligent observer; and in the twenty years during which he had devoted himself to astronomy, he had rendered great services to the science of ouranography. In private life he was a simple nonentity; he existed only for astronomy; he lived in the heavens, not upon the earth; and was a true descendant of the witty La Fontaine’s savant who fell into a well. He could talk of nothing but stars and constellations. He ought to have lived in a telescope. As an observer be had not his rival; his patience was inexhaustible; he could watch for months for a cosmical phenomenon. He had a specialty of his own, too; he had studied luminous meteors and shooting stars, and his discoveries in this branch of astronomical science were considerable. When ever minute observations or exact measurements and definitions were required, Thomas Black was chosen for the service; for his clearness of sight was something remarkable. The power of observation is not given to everyone, and it will not therefore be surprising that the Greenwich astronomer should have been chosen for the mission we are about to describe, which involved results so interesting for selenographic science.

We know that during a total eclipse of the sun the moon is surrounded by a luminous corona. But what is the origin of this corona? Is it a real substance? or is it only an effect of the diffraction of the sun’s rays near the moon? This is a question which science has hitherto been unable to answer.

As early as 1706 this luminous halo was scientifically described. The corona was minutely examined during the total eclipse of 1715 by Lonville and Halley, by Maraldi in 1724, by Antonio de’Ulloa in 1778, and by Bonditch and Ferrer in 1806; but their theories were so contradictory that no definite conclusion could be arrived at. During the total eclipse of 1842, learned men of all nations — Airy, Arago, Keytal, Langier, Mauvais, Otto, Struve, Petit, Baily, &c.— endeavoured to solve the mystery of the origin of the phenomenon; but in spite of all their efforts, “the disagreement,” says Arago, “of the observations taken in different places by skilful astronomers of one and the same eclipse, have involved the question in fresh obscurity, so that it is now impossible to come to any certain conclusion as to the cause of the phenomenon.” Since this was written, other total eclipses have been studied with no better results.

Yet the solution of the question is of such vast importance to selenographic science that no price would be too great to pay for it. A fresh opportunity was now about to occur to study the much-discussed corona. A total eclipse of the sun — total, at least, for the extreme north of America, for Spain and North Africa — was to take place on July 18th, 1860. It was arranged between the astronomers of different countries that simultaneous observations should be taken at the various points of the zone where the eclipse would be total. Thomas Black was chosen for the expedition to North America, and was now much in the same situation as the English astronomers who were transported to Norway and Sweden on the occasion of the eclipse of 1851.

It will readily be imagined that Thomas Black seized with avidity the opportunity offered him of studying this luminous halo. He was also to examine into the nature of the red prominences which appear on different parts of the edge of the terrestrial satellite when the totality of the eclipse has commenced; and should he be able satisfactorily to establish their origin, he would be entitled to the applause of the learned men of all Europe.

Thomas Black eagerly prepared for his journey. He obtained urgent letters of recommendation to the principal agents of the Hudson’s Bay Company. He ascertained that an expedition was to go to the extreme north of the continent to found a new fort. It was an opportunity not to be lost; so he set out, crossed the Atlantic, landed at New York, traversed the lakes to the Red River settlement, and pressed on from fort to fort in a sledge, under the escort of a courier of the Company; in spite of the severity of the winter, braving all the dangers of a journey across the Arctic regions, and arriving at Fort Reliance on the 19th March in the condition we have described.

Such was the explanation given by the astronomer to Captain Craventy. He at once placed himself entirely at Mr Black’s service, but could not refrain from inquiring why he had been in such a great hurry to arrive, when the eclipse was not to take place until the following year, 1860?

“But, Captain,” replied the astronomer, “I heard that the Company was sending an expedition along the northern coast of America, and I did not wish to miss the departure of Lieutenant Hobson.”

“Mr Black,” replied the Captain, “if the Lieutenant had already started, I should have felt it my duty to accompany you myself to the shores of the Polar Sea.”

And with fresh assurances of his willingness to serve him, the Captain again bade his new guest welcome to Fort Reliance.