“That is it. Imagine yourself turning around a circular table the center of which is occupied by a lamp representing the sun, while you represent the earth. Each of your walks around the table is one year. To represent things exactly, you must turn on your heels three hundred and sixty-five times while you circle the table once.” “It is as if the earth waltzed around the sun,” Emile suggested. “The comparison is not so well chosen as it might be, but it is exact. It shows that in spite of the giddiness of his age Emile has understood perfectly. A year is divided into twelve months which are: January, February, March, April, May, June, July, August, September, October, November, December. The unequal length of the months is sometimes confusing. Some have 31 days, others 30; February has 28 or 29, according to the year.” “For my part,” said Claire, “I should find it hard to tell whether May, September, and other months have 30 or 31 days. How can one remember which months have 31 days and which 30?” “A natural calendar, engraved on our hands, teaches us in a very simple way. Close the fist of the left hand. At the knuckles the four fingers, other than the thumb, from each a bump, separated by a hollow from the next bump. Place the index finger of the right hand in turn on these bumps and hollows, beginning with the little finger, and at the same time name the months of the year in order: January, February, March, etc. When the series of the four fingers is exhausted, return to the starting-point and continue naming the twelve months on the bumps and hollows. Well, all the months corresponding to the bumps have 31 days; all those corresponding to the hollows, 30. You must except February, answering to the first hollow. That has 28 or 29 days, according to the year.” “Let me try,” proposed Claire. “We’ll see how many days May has: January, bump; February, hollow; March, bump; April, hollow; May, bump. May has 31 days.” “It is as easy as that,” said her uncle. “My turn now,” interposed Jules. “Let us try September: January, bump; February, hollow; March, bump; April, hollow; May, bump; June, hollow; July, bump. And now? I am at the end of my hand.” “Now begin again and go on naming the months,” Uncle Paul instructed him. “You go on at the same point where you began?” “Yes.” “All right. August, bump. There are two bumps in succession. There are then two months together, July and August, that have 31 days?” “Yes.” “I will begin again. August, bump; September, hollow. September has 30 days.” “Why has February sometimes 28 and sometimes 29 days?” asked Claire.