of the smartest and fastest craft on the coast.--_Belgravia._ SUPPOSED CHANGES IN THE MOON. In this Magazine for August last I considered the moon's multitudinous small craters with special reference to the theory that some among those small craters may have been produced by the downfall of aerolithic or meteoric masses upon the moon's once plastic surface. Whether it be considered probable that this is really the case or not with regard to actually existent lunar craters, it cannot be doubted that during one period of the moon's history, a period probably lasting many millions of years, many crater-shaped depressions must have been produced in this way. As I showed in that essay, it is absolutely certain that thousands of meteoric masses, large enough to form visible depressions where they fell, must have fallen during the moon's plastic era. It is certain also that that era must have been very long-lasting. Nevertheless, it remains possible (many will consider it extremely probable, if not absolutely certain) that during sequent periods all such traces were removed. There is certainly nothing in the aspect of the present lunar craters, even the smallest and most numerous, to preclude the possibility that they, like the larger ones, were the results of purely volcanic action; and to many minds it seems preferable to adopt one general theory respecting all such objects as may be classed in a regular series, than to consider that some members of the series are to be explained in one way and others in a different way. We can form a series extending without break or interruption from the largest lunar craters, more than a hundred miles in diameter, to the smallest visible craters, less than a quarter of a mile across, or even to far smaller craters, if increase of telescopic power should reveal such. And therefore many object to adopt any theory in explanation of the smaller craters (or some of them) which could manifestly not be extended to the largest. Albeit we must remember that certainly if any small craters had been formed during the plastic era by meteoric downfall, and had remained unchanged after the moon solidified, it would now be quite impossible to distinguish these from craters formed in the ordinary manner.