This is the point of view of the majority of astronomers and it seems well taken. Yet many astronomers who have made a special study of the lunar surface for years under all conditions of illumination and phase, and have most carefully observed and mapped and photographed its characteristic markings, are agreed that there are evidences that changes are taking place on the moon, and recently Prof. W. H. Pickering has expressed the belief, substantiated by drawings, that there is a progressive change of color or darkening within certain lunar craters with the advance of the lunar day, indicating, in his opinion, a rapid vegetational growth that springs up in the height of the lunar day and dies out as the lunar night approaches.