"What is known in navigation as Great Circle Sailing," replied Bramsdean. "If a start is made somewhere on the 50th parallel North, the halfway time will be somewhere 50 degrees South, with a difference of 180 degrees of longitude."
"That's it," agreed Sir Reginald. "Now the difficulty arises where to find two suitable places answering to these conditions. With the exception of a small part of Cornwall the whole of Great Britain lies north of latitude 50.... Therefore, to reach the 50th parallel in the Southern Hemisphere would mean making a position far south'ard of New Zealand--where, I take it, there are no facilities for landing and taking in petrol.
"Nor is the vast extent of the United States any better off in that respect. I think I am right in saying that there is no habitable land diametrically opposite to any place in Uncle Sam's Republic."
Fosterdyke produced a small globe from a corner of the room in order to confirm his statement.
"And the old Boche is a jolly sight worse off," said Kenyon. "I don't suppose any British Dominion will tolerate him. It's certain he won't be allowed to fly over any Allied fortress, so where is he?"
"Paying the penalty for his misdeeds," replied Sir Reginald, grimly. "It's not exactly a case of vae victis. If he'd played his game, he would have taken his licking with a better grace because it wouldn't have hurt him so much."
"How many competitors are there for the Chauvasse Stakes, sir?" asked Bramsdean.
"A Yank, a Hun, and myself," replied Fosterdyke. "That is, up to the present. For some reason the idea hasn't caught on with our fellows. Probably there'll be a rush of entries later on--perhaps too late. I'll show you my little craft; but before doing so I'll give you a few details of the contest.
"My idea is to start from Gibraltar--for the actual race, of course. I'll have to take my airship there, but that's a mere detail. Why Gibraltar? Here's an encyclopædia, Kenyon. Look up the position of Gib."
"Lat. 36° 6' N.; long. 5° 21' W.," replied Kenyon, after consulting the work.