“The big one is twice as large, and so it will go twice as fast,” said Rollo.
“We shall see,” said Mary.
She then drew them both carefully out a little way on one side, and holding them there steadily a moment, she let them go. They immediately began to swing back and forth, together.
After a few oscillations, however, the large stone began to gain a little upon the other, and seemed to be moving faster. Presently it had gained half an oscillation, i. e. when the large one was moving forward, the small one would be coming back.
“The big one moves the fastest,” said Rollo.
“Not much,” said Mary.
“No,” said Rollo, “not much.”
“And I don’t think it is owing to the difference in the bigness of the stones.”
“What else can it be?” said Rollo. “They are exactly alike in all other respects.”