In 1755, when Cook was twenty-seven years old, war broke out between England and France, and there was a great demand for seamen for the navy of England. At that time the system of impressment was in vogue, and when Britain wanted sailors she took them, wherever and whenever she could find them. Press-gangs were sent out, under one or more officers, by ships of war in port needing more men. They visited the drinking-places and taverns of the town and captured all the seamen they could find, usually more or less intoxicated, and compelled them to go on board of the man-of-war. They were forced to do duty. Sometimes the unlucky tars were taken from the vessels to which they belonged, whether in port or at sea. This impressment was not always confined to British seamen, and this system was one of the causes which led to the war of 1812 between England and the United States. Though the law sanctioning this abuse was never repealed, press-gangs became obsolete half a century ago. Cook's ship was in the Thames at this time, and he was liable to impressment, for mates were not exempt, though captains were. Like all British seamen, he had a dread of being forced into the naval service, oftener because they were forced than for any other reason. He concealed himself, and used all the precautions he could to avoid such a calamity, as he then regarded it. But he faithfully reconsidered the subject, and concluded to enter the navy by voluntary enlistment, thus escaping impressment, which would be an outrage upon his manhood. He began his service on board the Eagle, a sixty-gun ship, which was soon after commanded by Captain Palliser. Cook was not only an able and skilful seaman, but he diligently and faithfully performed every duty, so that he soon attracted the attention of his officers. His friends at home had endeavored to do something for him, and his commander received a letter from a member of Parliament commending the seaman to his favor. The captain acknowledged the merit of Cook in his reply, but stated that he had been in the navy for so brief a period that he could not be made a commissioned officer, but in due time, if he proved worthy, a master's warrant might be obtained for him. Four years after he entered the service a strong interest secured this promotion for him. In this capacity he was assigned to the frigate Mercury, which was ordered to North America, where she became one of the fleet that operated in connection with the army of General Wolfe in the siege of Quebec.