Two screw-steamers, the _Alert_ of 751 tons, and the _Discovery_ of 668 tons,--being strengthened by every means science could devise for resisting the Polar ice,--were fitted out, and Captain Nares was selected to command the expedition. Commander Markham, who had considerable experience, was appointed to act under him on board the _Alert_. Captain Nares and Commander Markham were the only two officers in the expedition who had previously crossed the Arctic Circle, but all the others were selected for their known high character and scientific attainments. The other officers of the _Alert_ were Lieutenants Aldrich, Parr, Giffard, May, and Sub-Lieutenant Egerton. Various important duties connected with the scientific objects of the expedition were undertaken by them. Dr Colan, the fleet surgeon, was known as a good ethnologist; Dr Moss, in addition to other scientific attainments, was an excellent artist. Captain Fielden went as ornithologist; Mr Wootton, the senior engineer, was an officer of experience; Mr White was the photographer of the _Alert_; and Mr Pullen, the chaplain, was a botanist. Besides the officers, the complement of the _Alert_ was made up of petty officers, able seamen, marines, and others, forty-eight in all, some of whom were well able to assist the superior officers in their scientific duties. Christian Neil Petersen, a Dane, who had served in the expedition of Dr Hayes, was engaged as interpreter and dog-driver on board the _Alert_. The _Discovery_ was commanded by Captain Henry Stephenson. His active staff consisted of Lieutenants Beaumont, Rawson, Archer, Fulford; Sub-Lieutenant Conybeare; Doctors Ninnis and Coppinger; engineers Gartmel and Miller; assistant paymaster Mitchell, a photographer and good artist. Mr Hodson was the chaplain, and Mr Hart the botanist.