"Go easy, carry lots of quinine, don't waste ammunition, and count ten before you pick a quarrel with a native," had been his simply laid-down rules for getting along in Africa, and these rules the boys had determined to adhere to strictly.
"Say, is this going to be a hunting trip or an invasion of Africa?" inquired Billy, quizzically as Harry sorted out and Frank read off ceaselessly the apparently interminable inventory of the supplies of the Chester party. "I'm getting writer's cramp."
"A hunting party of course," laughed Frank, "but you know that hunters who go into the bush depending on their rifles usually come out a good deal thinner than when they went in.
"That's so," assented Billy, "but when we have a sixty-mile aeroplane like the Golden Eagle II we can easily fly out to civilization in case of necessity."
"Yes, if we have enough gasoline," assented Harry, "but how much can we carry into the bush?"
"Just enough for our purposes and no more," replied Frank, readily, "fortunately the soluble tablets of picric and glycerine will help out our supply materially. A few of these tablets dissolved in gasoline render the efficiency of one ordinary gallon equal to three; but I don't care to use them except in a case of absolute necessity as they are very hard on an engine."
"Then we can count on every gallon we carry being of triple efficiency?" asked Billy.
"Certainly," replied Frank, who had invented the tablets in question, and which were an extremely useful addition to the equipment of the modern aviator. As the boys worked on and the equipment, as it was classified, was packed away in the cases assigned to each class of articles, there came a sharp knock at the door of the garage building and a servant entered with a special delivery letter to Frank. The boy tore it open eagerly and then gave a low whistle of astonishment.
"Read it out, Harry," he said, handing the missive to his brother. "It concerns all of us."
Harry took it and read as follows: