“I see the defect,” said Mr. Seymour, “which a little string will easily remedy.”
A piece of string was instantly produced from that universal depot, the breeches pocket of a school-boy. Mr. Seymour said he should bind a portion of it around the end of the piston.
“What do you mean by the piston?” enquired Tom.
“The rod which moves up and down in the cylinder, or tube; and, unless its end fit so exactly as to prevent the admission of air, it is clear that the squirt cannot draw any water. It was for the purpose of making this part fit tightly that I wanted the string, and you will now perceive that the instrument is ready for use:--fetch me a vessel of water.”
Tom soon produced the water, and, on placing it on the ground, requested that he might be allowed to fill the squirt. This he accordingly effected without difficulty, and, on pressing down the handle, he projected a stream of water to a considerable distance.
“I perceive,” said Tom, “that the stream describes a curve, like my ball.”
“To be sure; it is under the joint influence of the same forces, viz. that of projection and of gravity. But explain the operation of the squirt.”
“As soon as I raised the piston, an empty space was left in the lower part of the cylinder, which I suppose would have remained as a vacuum, had not the water rushed into it.”
“And why did the water rush into it?”
Tom hesitated.