“Not by any means as scientific as it might be, or as it ought to be,” I replied, laughing. “But, really, if you wish to understand these things you should not be too much afraid of the bugbear ‘science.’ Science makes the world go nowadays, and everybody ought to know a little about it, just as everybody with any pretensions to education a hundred years ago had to learn more or less Greek and Latin. But let me continue a little farther. Since the force of attraction on the moon is only one sixth as great as it is on the earth, the weight of all bodies is in the same proportion. Pardon me if I guess at your weight; it is, perhaps, 120 pounds. Very well, translated to the moon you would weigh only 20 pounds.” “Dear me, then skipping the rope may be the favorite pastime of middle-aged ladies on the moon.” “And throwing somersaults that of gray-haired lunar gentlemen. Let me tell you of one very interesting consequence of the small force of the moon’s gravity, which affects not merely the weight of bodies but the flight of projectiles, and, indeed, all motions of every kind. You will see, when we come to the photographs, that some of the lunar volcanoes are of a magnitude almost incredible. This is doubtless due to the fact that the ejections from volcanic craters there were able, with no greater expenditure of explosive force, to attain an elevation six times that which they would attain if thrown from a volcano on the earth. During the eruption of Vesuvius in April, 1906, the column of smoke, steam, and cinders from its crater reached, according to the measures of Professor Matteucci, a maximum height of about eight miles. On the moon the same force would have blown these things almost fifty miles high! It is not difficult, in view of such facts, to see how the giant volcanic craters and mountain rings of the moon were formed.” In the meantime the eclipse continued, and, having tired of watching it, we returned to the drawing-room. “When shall we see these famous photographs and begin our imaginary journey in the moon?” my companion asked. “To-morrow,” I replied. “But I shall have to demand one more brief exercise of your patience this evening, while I finish with this subject of eclipses.” “Then we are not through yet?” “Not quite, for I have not yet told you why the moon is not eclipsed every time she approaches the earth’s shadow, and why she does not eclipse the sun once every month at the time of New Moon.” “Well, tell me then, and I promise to be as interested as possible; only please don’t talk any more mathematics than is absolutely necessary.”