"And you actually got a plunge-bath every morning? said the Sub-Warden, seemingly in continuation of a conversation with the Professor. "Even at the little roadside-inns?"
"Oh, certainly, certainly!" the Professor replied with a smile on his jolly face. "Allow me to explain. It is, in fact, a very simple problem in Hydrodynamics. (That means a combination of Water and Strength.) If we take a plunge-bath, and a man of great strength (such as myself) about to plunge into it, we have a perfect example of this science. I am bound to admit," the Professor continued, in a lower tone and with downcast eyes, "that we need a man of remarkable strength. He must be able to spring from the floor to about twice his own height, gradually, turning over as he rises, so as to come down head first."
"Why, you need a flea not a man!" exclaimed the Sub-Warden.
"Pardon me," said the Professor. "This particular kind of bath is not adapted for a flea. Let us suppose," he continued, folding his table-napkin into a graceful festoon, "that this represents what is perhaps the necessity
