THE question of meteors on the moon is not now raised for the first time. In my article on astronomy in “Science in Modern Life”, vol. i., p. 35 (I give this, not as being the first mention of the subject, but because it is the most accessible source), I wrote:—“There is one puzzling question raised by Prof. Shaler, i.e. how is it that the fall of meteors on the moon, which must be as dense as those falling on the earth, has not covered all the markings with a veil and obliterated the differences of tint? It has, however, been calculated that even if the atmospheric density at the surface be only 1/10,000 of that on earth (a quantity which it may well exceed), then, since the rate of decrease is so much slower than on the earth, at a height of something over 40 miles the densities of the atmospheres would be equal, and at still greater heights that of the moon would be the denser. Now most of the meteors that enter our air are completely burnt up at greater heights than this, so that the thin lunar atmosphere may actually be as effective for stopping meteors as our own”.