“I cannot say,” observed Tom, “how I should set about it.”
“Well, fetch your kite, and I will explain the method.”
Tom soon produced it, and the tail having been removed, Mr. Seymour proceeded as follows:--
“I now,” said he, “suspend the kite by the loop at its bow, and since it is at rest, we know that the centre of gravity must be exactly below the point of suspension; if, therefore, we draw a perpendicular line from that point, which may be easily done by a plumb-line, with a weight attached to it, such a line will represent the line of direction (as indicated by A B in fig. 13)”.
“It is clear enough,” said Tom, “that the centre of gravity must lie in the line A B, but how are we to find in what part of it?”
“By suspending the kite in another direction,” answered Mr. Seymour, who then hung it up in the position represented at fig. 14, “and then by drawing another perpendicular from the new point of suspension.”
“The centre of gravity,” said Louisa, “will in that case be in the line c d, as it was before in that of a b.”
“In both the lines!” exclaimed Tom, with some surprise; “it cannot be in two places.”