2. Undivided command in an expedition is the first of all rules; but if there be any division of command in a subordinate expedition by sea or land, the duties and rights of its commander must be clearly and exactly defined. In recent times the command of a Polar expedition has sometimes been conferred not on a seaman, but on a man of science, as in the cases of Kane, Hayes, Nordenskjöld, and Torell. Where the investigation of questions connected with Natural History is the aim and object, this precedent is admissible, but it should never be observed where the commander has an important part to fulfil as a navigator. The command of an expedition has never been conferred on a man of science by the English government. In the very commencement, indeed, of Polar discovery, an English expedition was placed under the command of Sir Hugh Willoughby, who was not bred a sailor, but down to the seventeenth century, even in their naval campaigns, such men were appointed to naval commands. The Dutch expeditions of the sixteenth century generally adopted a destructive division of command, under supercargoes and pilots, representing the mercantile and nautical elements: confusion and discord were the inevitable consequences. 3. Next to the selection of a commander, the selection of the crew demands the greatest care. This ought to be made some time before the expedition starts, in order that those unfit for the service may be discovered, and their places supplied by others; this cautious mode of procedure, and not a preference for any particular nationality, will secure the most effective crew. Although seamanlike qualities do not belong in the same degree to every nation, time and pains only are needed to secure a picked crew for a North-Pole expedition from almost any nation. Endurance of cold is not the only test of effectiveness, although this is a very common assumption; but a sense of duty, perseverance, and resolution are the virtues of a seaman. Habit soon teaches men to conquer cold, and inexorable necessity often hardens weaklings into heroes for Arctic discovery. A certain degree of intelligence is of high importance in the crew. In many cases resolution in the midst of dangers depends on their capacity to observe and think, even on their possessing certain branches of knowledge. The greater part of the crew of the _Tegetthoff_ had these advantages. But men who, in a heavily-laded sledge, leave the old and take to recently-formed ice, without noticing the difference,—who observe a frost-bitten foot several hours after the mischief has been done,—who lose their cartridges, know nothing of their rifle, and little more of their compass, or who pass on without observing the configurations of the land, possess an indifference indeed, but of a kind very dangerous to themselves and to the whole party, though they may despise death as much as Achilles is said to have done.