aluminum seat fitted with clamps to screw to the framework, and
handles to grasp hold of tightly when the craft was in mid-air.

"Let her go," cried Frank, as soon as the delighted Billy had taken
his place.

Sanford and Le Blanc, one at each of the propellers, gave them a few
twists, and after about the third silent revolution there came the
startling roar of the exhaust that told the boys that all the
cylinders were getting down to work. Blue flames and smoke belched out
of the vents and the mechanics sprang back, as the propellers whirled
round at a pace that made them seem blurred shadows.

"Hang on till I get up speed," shouted Frank to the two mechanics,
who, with several volunteer helpers, seized hold of the rear framework
and held the struggling aeroplane back with all their might. Her frame
shook as if it was being swept by some mighty convulsion. The racket
was terrific, ear-splitting. The wind from the propellers blew hats in
every direction and streamed out the hair of the men holding the
aeroplane back, as if they had been poking their faces into an
electric fan.

Faster and faster the propellers revolved, as Frank increased the
power of his mixture and advanced the spark. At last, when the men
holding the craft were shouting that they couldn't hang on much
longer, Frank dropped his hand, the signal that the craft was to be
released.

Like a scared jack-rabbit, the big-winged craft shot forward over the
uneven ground at race-horse speed. Several boys on bicycles, who