seven o'clock
`` I see that the members of your Congress insist that a protective tariff is for the primary purpose of preventing foreign competition with home industries . As I do not believe that you will find an aviation industry on the Yukon , I guess I am safe in letting you take your machine through . '' The boys also visited the police barracks and found their three friends of the forest patrol whom they again heartily thanked . At seven o'clock , at what would have been night anywhere else , they went aboard the `` Yukoner '' with the aeroplane , and an hour later cast off lines for Dawson . Here another exhibition was made , and under Swiftwater 's guidance a visit paid to the mining camps . Two days later , Colonel Snow and the boys , accompanied by Swiftwater , having taken leave of their new made friends at Dawson , embarked on a small launch -LRB- a new importation from the States -RRB- and started on a leisure trip down the Yukon , intending to use this means of river travel as far as the military post at Fort Gibbon , at the mouth of the Tanana , up which river Swiftwater was to proceed to the Fairbanks mining district , the latest discovered and most important in Alaska . Colonel Snow 's plan was to drop down the river in the swift motor boat , stopping at several army posts where he had friends , some of whom had come up from Seattle with the party and had extended the hospitalities of the various posts to them .