"I thought not; it is of no use waiting for your puzzle-brains to make it out. I must talk to those who can understand."
The professor took the cube, and, on attaching it to the hook of the steelyard, found that its apparent weight was one kilogramme and four hundred and thirty grammes.
"Here it is, gentlemen; one kilogramme, four hundred and thirty grammes. Multiply that by seven; the product is, as nearly as possible, ten kilogrammes. What, therefore, is our conclusion? Why, that the density of Gallia is just about double the density of the earth, which we know is only five kilogrammes to a cubic decimeter. Had it not been for this greater density, the attraction of Gallia would only have been one-fifteenth instead of one-seventh of the terrestrial attraction."
The professor could not refrain from exhibiting his gratification that, however inferior in volume, in density, at least, his comet had the advantage over the earth.
Nothing further now remained than to apply the investigations thus finished to the determining of the mass or weight. This was a matter of little labor.
"Let me see," said the captain; "what is the force of gravity upon the various planets?"
"You can't mean, Servadac, that you have forgotten that? But you always were a disappointing pupil."
The captain could not help himself: he was forced to confess that his memory had failed him.