At the same time when the affirmation is made that the moon is 'a world where there is no weather, and where nothing ever happens,' the most careful modern students of lunar matters would be the first to question such a statement. Even supposing it to be true that no concrete evidence of change upon the lunar surface can be had, this would not necessarily mean that no change takes place. The moon has certainly never been studied to advantage with any power exceeding 1,000, and the average powers employed have been much less. Nasmyth puts 300 as about the profitable limit, and 500 would be almost an outside estimate for anything like regular work. But even assuming the use of a power of 1,000, that means that the moon is seen as large as though she were only 240 miles distant from us. The reader can judge how entirely all but the very largest features of our world would be lost to sight at such a distance, and how changes involving the destruction of large areas might take place and the observer be none the wiser. When it is remembered that even at this long range we are viewing our object through a sea of troubled air of which every tremor is magnified in proportion to the telescopic power employed, until the finer details are necessarily blurred and indistinct, it will be seen that the case has been understated. Indeed it may be questioned if the moon has ever been as well seen as though it had been situated at a distance of 500 miles from the earth. At such a distance nothing short of the vastest cataclysms would be visible; and it is therefore going quite beyond the mark to assume that nothing ever happens on the moon simply because we do not see it happening. Moreover, the balance of evidence does appear to be inclining, slightly perhaps, but still almost unquestionably, towards the view that change does occur upon the moon. Some of the observations which seem to imply change may be explained on other grounds; but there is a certain residuum which appears to defy explanation, and it is very noteworthy that while those who at once dismiss the idea of lunar change are, generally speaking, those who have made no special study of the moon's surface, the contrary opinion is most strongly maintained by eminent observers who have devoted much time to our satellite with the best modern instruments to aid them in their work.