“Ah!” said the professor, more than half speaking to himself, “a circumference of 1,400 miles would give a diameter of about 450 miles. That would be approximately about one-sixteenth of the diameter of the earth.” Raising his voice, he continued, “Gentlemen, in order to complete my account of my comet Gallia, I require to know its area, its mass, its volume, its density, its specific gravity.” “Since we know the diameter,” remarked the lieutenant, “there can be no difficulty in finding its surface and its volume.” “And did I say there was any difficulty?” asked the professor, fiercely. “I have been able to reckon that ever since I was born.” “Cock-a-doodle-doo!” cried Ben Zoof, delighted at any opportunity of paying off his old grudge. The professor looked at him, but did not vouchsafe a word. Addressing the captain, he said, “Now, Servadac, take your paper and a pen, and find me the surface of Gallia.” With more submission than when he was a school-boy, the captain sat down and endeavored to recall the proper formula. “The surface of a sphere? Multiply circumference by diameter.” “Right!” cried Rosette; “but it ought to be done by this time.” “Circumference, 1,400; diameter, 450; area of surface, 630,000,” read the captain. “True,” replied Rosette, “630,000 square miles; just 292 times less than that of the earth.” “Pretty little comet! nice little comet!” muttered Ben Zoof. The astronomer bit his lip, snorted, and cast at him a withering look, but did not take any further notice. “Now, Captain Servadac,” said the professor, “take your pen again, and find me the volume of Gallia.” The captain hesitated. “Quick, quick!” cried the professor, impatiently; “surely you have not forgotten how to find the volume of a sphere!” “A moment’s breathing time, please.” “Breathing time, indeed! A mathematician should not want breathing time! Come, multiply the surface by the third of the radius. Don’t you recollect?” Captain Servadac applied himself to his task while the by-standers waited, with some difficulty suppressing their inclination to laugh. There was a short silence, at the end of which Servadac announced that the volume of the comet was 47,880,000 cubic miles. “Just about 5,000 times less than the earth,” observed the lieutenant. “Nice little comet! pretty little comet!” said Ben Zoof. The professor scowled at him, and was manifestly annoyed at having the insignificant dimensions of his comet pointed out in so disparaging a manner. Lieutenant Procope further remarked that from the earth he supposed it to be about as conspicuous as a star of the seventh magnitude, and would require a good telescope to see it. “Ha, ha!” laughed the orderly, aloud; “charming little comet! so pretty; and so modest!”