Of the various expeditions which have departed from our shores, for the purpose of extending discovery into the arctic regions, none have appeared more likely to achieve the grand object in view, than that which has just sailed under the orders of Captain Back, nor is it possible to contemplate the various acquisitions made to geography, by the several modern voyages of discovery in the vicinity of Baffin’s Bay, without feeling more than ordinary interest in the result of that which is now going forward. It is not with respect to the actual possibility of the passage to Bhering’s Strait north of America, that our interest is now excited—that is a question which we have considered as settled since the first memorable expedition conducted by Sir Edward Parry; and whenever the north-west passage to China shall be performed by any ship, it may be considered a fortuitous event which the energy and intrepidity of British seamen have shewn to be practicable, under circumstances of weather, &c. favourable to navigation. The object of the present expedition may literally be considered to lie, in defining the north-east extreme of the American continent. Until the arrival of Captain Back in England, from his land journey in search of Sir John Ross, we were to consider the western boundary of Prince Regent’s Inlet as this north-eastern extreme; but no sooner does Captain Back appear, than “the wide, the open sea,” is reported some hundreds of miles to the southward and westward of that part of the arctic regions, and also that a tide was running into it from the westward. At page 623 of our last volume, the reader will find some account of the last discovery of Back; and it is for the purpose of tracing the shore of this “open sea,” from the mouth of the river Back, to the eastward as far as Melville peninsula, and to the westward as far as Cape Turnagain, that the Terror has departed from England. Were we to hazard an opinion, we should say, that it appears likely that the land called North Somerset by Parry will be found to consist of a series of islands.

The Terror sailed from the Nore on the 16th of June, accompanied by the Rhadamanthus steam-vessel (for the purpose of towing her as far as wind and weather would permit,) and on clearing the Pentland Frith, Captain Back would shape his course for Cape Farewell, and, passing up Hudson Strait, would enter Wager River or Repulse bay as most convenient, and, having secured the ship there, would then proceed to cross the isthmus which separates them from the bottom of Prince Regent’s Inlet. Two light boats will be conveyed across this Isthmus, one of which will proceed to explore the coast to the north-east, as far as the Strait of the Fury and Hecla, while the other will go west towards the mouth of the river Back. Thus the southern shore of the Boothian Gulf will be defined, and thereby also the breadth of the Isthmus connected with Melville Peninsula, which separates it from the Atlantic waters.

In the immediate neighbourhood of their proceedings, is the position of the magnetic pole; and the magnetic observations which will be obtained by Captain Back and his officers, will give additional interest to the results of this voyage. The time it may require to be performed in must remain uncertain, as it is more than probable that such discoveries may be made, either of a geographical or other nature, as will induce Captain Back to avail himself of the discretionary power invested in him of wintering in Wager river, in which case his return would be looked for by the end of next summer. He is accompanied by officers who are well qualified to assist him in his arduous enterprise. Lieutenants Smyth and Owen Stanley are officers already well known; the former from his late journey from Lima to Para, and the latter from his surveys in the Mediterranean; and the services of Mr. Saunders, the master, will no doubt be turned to a good account in the numerous scientific pursuits which will occupy the whole party during their interesting voyage.