Before 1901, units of soldiers from all six Australian colonies had been active as part of British forces in the Boer War. When the British government asked for more troops from Australia in early 1902, the Australian government obliged with a national contingent. Some 16,500 men had volunteered for service by the war's end in June 1902. But Australians soon felt vulnerable closer to home. The Anglo-Japanese Alliance of 1902 "allowed the Royal Navy to withdraw its capital ships from the Pacific by 1907. Australians saw themselves in time of war a lonely, sparsely populated outpost." The impressive visit of the US Navy's Great White Fleet in 1908 emphasised to the government the value of an Australian navy. The Defence Act of 1909 reinforced the importance of Australian defence, and in February 1910, Lord Kitchener provided further advice on a defence scheme based on conscription. By 1913, the Battle Cruiser Australia led the fledgling Royal Australian Navy. Historian Bill Gammage estimates on the eve of war, Australia had 200,000 men "under arms of some sort".