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THE POPULAR SCIENCE MONTHLY.— SUPPLEMENT. 



ing larger and more diffused. In a splendid view, 

 taken April 19, 1872, when the moon was a day 

 older, the light region can be clearly recognized. 

 In a view of the full moon taken June 2, 1871, I 

 can detect no trace of the crater. 



I note also that in a view of the moon near her 

 first quarter, taken by Mr. Ellery, with the great 

 reflector of the Melbourne Observatory, the differ- 

 ence of tint of the region occupied by the supposed 

 new crater can be most distinctly recognized. 



It is hardly necessary to point out, perhaps, 

 that the recognition of a decided difference of 

 color in this part of the so-called Sea of Vapors, 

 where none of the lunar map-makers have indi- 

 cated any peculiarity of the kind, tends to throw 

 some degree of doubt on the negative evidence 

 which can alone be adduced in favor of a change 

 of any sort. If the light-tinted spot which has 

 certainly existed since 1865, and doubtless for 

 ages, escaped the scrutiny of lunarians, so also 

 might a dark spot such as is seen when the crater 

 is under low solar illumination. The light-tinted 

 spot is not a mere photographic feature — to dis- 

 tinguish thus a peculiarity of tint which shows 

 in a photograph yet escapes ordinary visual ob- 

 servation. The feature exists still. It can be 

 recognized when the moon is ten days old, though 

 it is not so obvious to the eye as in the photo- 

 graph. I find, however, that even those observers 

 whose attention has been specially directed to 

 the supposed new crater have failed to recognize 

 the light spot which comes into view a day or so 

 after the crater has assumed the same tint as the 

 surrounding plain. Thus it seems quite possible 

 that the crater may have been always in its pres- 

 ent condition. 



But, in any case, there has probably been no 

 volcanic change. Here, if a change has taken 

 place at all, the floor of a crater two miles in 

 diameter, after undergoing for millions of years 

 the expansion resulting from the tremendous heat 

 of lunar mid-day (with a sun nearly vertical) and 

 the contraction resulting from the fearful cold of 

 lunar midnight, has at length yielded to lunar 

 gravity, falling in fragments upon the sloping 

 walls of the hollow space beneath. That changes 

 such as this should from time to time — though 

 probably at enormously long intervals — take 

 place in the moon's crust, is to be expected. So 

 far from regarding them as incredible or even 

 surprising, we should perhaps consider the real 

 wonder to be that they are not more frequently 

 recognized in a surface exposed to such amazing 

 vicissitudes of heat and cold. Whether the rec- 

 ognition of the downfall of a wall here or of a 

 crater-floor there is an adequate reward for the 

 labors devoted to lunar phenomena by men like 

 Schroter, Lohrmann, Madler, and Schmidt, may 

 be a question with many — precisely as many fail 

 to understand how a coleopterist can devote the 

 best part of his life to determine the genealogy of 

 Pediculus Meiittae. But we can only hope to 

 learn from labors such as these the actual con- 

 dition of our companion-planet ; and perhaps we 

 may thus even learn something of the changes 

 which will affect our own earth millions of years 

 hence — 



" When the old hulk we tread shall be a wreck, 

 A slag, a cinder— drifting through the sky, 

 Without its crew of fools." 



Contemporary Review. 



ALCOHOLIC BEAIN-DISOKDEES. 



By EOBEET LAWSON, M. B. 



THE large number of cases of insanity which 

 owe their origin, directly or indirectly, to 

 excessive drinking, not only makes the observa- 

 tion of such cases, when massed in a large asy- 

 lum, comparatively easy, but renders it necessary 

 that an accurate knowledge of the varieties and 

 tendencies of this form of brain-disease should be 

 arrived at. In the notes which I am about to 

 record I shall not presume to aim at anything like 

 a complete study of the subject, more especially 

 as Dr. Magnan's excellent work on Alcoholism, 



translated by Dr. Greenfield, has so recently been 

 placed in the hands of the English public. My 

 motive will be to record, in as simple a manner 

 as possible, some casual observations which have 

 been almost thrust upon me while engaged as an 

 assistant medical officer in asylums which have 

 provided' shelter and treatment for the insane al- 

 coholic patients of the densely-populated counties 

 of Middlesex and York. For my own convenience 

 I shall speak of cases of alcoholic brain-disorder 

 under two heads. The first class of cases will 



