Of discussion, pro and con, there was much. Indeed, they sat up until after midnight after the reading of Dr. Todd's letter, talking over the contemplated journey, and gradually the details of the trip, including all preparations for it, were worked out.

Jack and Mark put into the affair, once they were determined to aid the professor, their characteristic energy. Professor Henderson wired his brother scientist that he would undertake the journey to Alaska, and accepted the ten thousand dollars to defray expenses. Andy Sudds made characteristic preparations for hunting the big game of the Alaskan mountains. Washington White built a traveling coop of very light but strong material for his pet Shanghai, and then announced himself as ready to depart for the Arctic Circle.

The instructions and map furnished by Dr. Todd, locating the very spot beyond the Endicott Range where the rare herb had been plucked by the miner, showed it to be in a very wild region indeed. There was a native settlement named Aleukan within a hundred miles of the valley where the herb was supposed to grow in abundance. Professor Henderson determined to lay their course for this place.

But the nearest white man's town was Coldfoot, on the other side of the mountains. There was a trail, however, passable in summer for a dogtrain from Coldfoot to Aleukan; and a dogtrain could likewise pass from the native village to the valley where the miner had found the herb.

These facts the professor and his young associates discovered as soon as Dr. Todd's instructions arrived. They made their plans accordingly.

By telegraph the professor ordered a trainload of supplies to be started at once from Fort Yukon. First, these supplies would go by boat down the Yukon Flats and up the Chandler River, past Chandler and Caro, beyond which latter town there was a good road over a small range of hills to Coldfoot. This trail was open at all seasons and there was a regular system of transportation into Coldfoot.

From that town dogs and men would be hired to take the supplies on to Aleukan. These arrangements were made through an express company, and in three days the professor received word that the supplies were already aboard a small steam vessel which had left the Fort Yukon dock for the trip to Caro.

The trip by boat and overland for the supply train would consume about a week or two, providing nothing untoward happened to delay it. And the season was favorable to a quick journey.

But the professor and his young comrades figured that the Snowbird, following the shortest air-line to the far side of the Endicott Range, could make the trip in much shorter time. The distance "as the crow flies" was from 3,700 to 3,800 miles from their point of departure. Under favorable conditions the great flying machine should travel ninety miles an hour on the average. Unless there was a breakdown, or they ran into a heavy storm, which would necessitate their descending to the earth, they could count upon the Snowbird being in the vicinity of Aleukan within three or four days' time at the longest.

In the flying machine itself they could carry a supply of concentrated foods, medicines, necessities of many kinds, and their arms. It was probable that meat could be had for the killing in the valley to which they were bound, and the Indians at Aleukan could be hired to supply necessary food for a time. But the professor did not propose to take his friends into the wilderness without completely warding off disaster.