"Yes, by friction against the atmospheric layers: the quicker its motion, the greater resistance it encountered."
"That of course I admit, but your v squared and your v prime squared rattle in my head like nails in a box!"
"The usual effect of Algebra on one who is a stranger to it; to finish you, our next step is to express numerically the value of these several symbols. Now some of them are already known, and some are to be calculated."
"Hand the latter over to me," said the Captain.
"First," continued Barbican: "r, the Earth's radius is, in the latitude of Florida, about 3,921 miles. d, the distance from the centre of the Earth to the centre of the Moon is 56 terrestrial radii, which the Captain calculates to be...?"
"To be," cried M'Nicholl working rapidly with his pencil, "219,572 miles, the moment the Moon is in her perigee, or nearest point to the Earth."
"Very well," continued Barbican. "Now m prime over m, that is the ratio of the Moon's mass to that of the Earth is about the 1/81. g gravity being at Florida about 32-1/4 feet, of course g x r must be—how much, Captain?"
"38,465 miles," replied M'Nicholl.
"Now then?" asked Ardan.
