“Very well,” said Rollo, “we will; and then we shall see that the big one will vibrate the quickest.”
“Let us think, first, what other circumstances there are, that it may depend upon.”
“I can’t think of any thing else,” said Rollo.
“Why, there is the nature of the body which we suspend. A piece of cork may oscillate differently from a piece of stone.”
“Yes,” said Rollo, “it will oscillate slower.”
“We must not decide,” said Mary, “in our own minds, before we try the experiment. We must leave our minds free to observe the facts, and wait until we make the experiment, before we come to any conclusion, or else we shall not be good experimenters.”
“Why not?” said Rollo.
“Because,” said Mary, “when persons make up their minds beforehand what the facts will be, they are very apt not to observe fairly. So good observers or experimenters always take care to keep their minds free and unbiassed.”
“Well,” said Rollo, “and what else is there that the oscillations may depend upon?”