In the days that followed Tom and his friends worked hard. The air glider was made as nearly perfect as any machine is, and in a fairly stiff gale, that blew up about a week later, Tom did some things in it that made his friends open their eyes. The young inventor had it under nearly as good control as he had his dirigible balloons or aeroplanes.
The big airship, too, was made ready for the long voyage, extra large storage tanks for gasolene being built in, as it was doubtful if they could get a supply in Siberia without arranging for it in advance, and this they did not want to do. Besides there was the long ocean flight to provide for.
"But if worst comes to worst I can burn kerosene in my motor," Tom explained, for he had perfected an attachment to this end. "You can get kerosene almost anywhere in Russia."
At last word was received from Russia, from some Revolutionist friends of the exile, stating that his brother was supposed to be working in a certain sulphur mine north of the Iablonnoi mountains, and half way between that range and the city of Iakutsk.
"But it might be a salt mine, just as well," said Mr. Petrofsky, when he told the boys the
