So I said to Jack, “Lower the car a little, then take the steering gear in hand and let me try to estimate our speed.”
He let the car descend slowly until he could distinguish the trees and other prominent features of the landscape. Then he took the steering gear into his own hand and I looked over the side of the car. The forest was thick in parts, but there were wide spaces of treeless plain; and we were just passing over a range of hills which I think I am right in identifying with a range that we had observed at a distance of several miles when we were among the blacks.
I took particular notice of the larger trees, trying to guess their distance each from the other and referring to my watch every few seconds.
“What do you make of it?” said Jack at last, when he had raised the car to its former height.
“It is hard to fix it,” said I, “but I cannot think that we are travelling less than twenty-five miles an hour and I should say much more probably thirty.”
[247] Wilbraham. Ah! and how far do you suppose that we have to travel from the start?
Easterley. Say fifteen days passed from our parting with Mr. Fetherston until we reached the valley, and I am pretty sure we made an average of thirty miles a day. But of course that was nearly all westing. I don’t think that our furthest point could be quite as much as three hundred miles from the wire. I don’t think that your own estimate can be much out of the way, but we are perhaps a little under the mark.
Wilbraham. Ah! if the figures are right the sum is easy; we ought to cross the wire about six o’clock.
Easterley. Yes, but look here; thirty miles an hour is possibly an overestimate of our speed; and three hundred miles is possibly an underestimate of our distance. Besides, we shall not be able to keep up our present speed. The wind is already falling, and may be against us in an hour or two. That would knock, say, ten miles an hour off the rate of speed at which we are now travelling.
Wilbraham. It might, but that is another overestimate; we may fairly reckon on travelling all night at within five miles of our present rate of speed.