828 TrANSACTIOXS of the AmERICAX lyS'UTVTE. 



itself must have undergone very remarkable changes since the period 

 of its activity, for it has become so dark and smooth as to be closed 

 now amongst the " desert wastes " in contra-distinction to the l)right 

 rugged appearance of the more recent formations. 



If those regions were merely the earlier formations smoothed down 

 into "desert wastes," they would have become brighter instead of 

 darker in appearance, because no matter what may be the nature of 

 any material, the smoother its surface the more light it will reflect ; 

 consequently those ancient regions have not only been denuded and 

 smoothed, but some other change must have been added to have pro- 

 duced the dark shade which they present. 



If we examine the ray systems which emanate from Copernicus, 

 Kepler and Aristarchus, we shall find that the darkest portions are 

 the lowest, and in ascending from the valley toward the apex of the 

 streak or rims of the basin, it becomes gradually lighter until the 

 higher regions come out in light. Now, if an observer upon the 

 moon turned a telescope upon the mountain region of our own earth, 

 exactly this phenomenon would be presented to his view ; and it 

 would be occasioned by the mountain tops being bare and conse- 

 quently reflecting more light, and as the vision descended into the 

 valley, a gradual darkening would take place in the exact proportion 

 in which vegetation increased in luxurious development. 



The sun itself bears testimony in the same direction. Those dark 

 regions appear of a luminous gray in which the blue predominates, 

 and consequently they should photograph more brigliter than they 

 look — instead of which they take so darkly as to resemble very much 

 the effects produced in the photograph by our own vegetable greens, 

 which implies that the color seen in the telescope is not that of the 

 actual local color of the so called " desert wastes" of the moon. 



If those regions were either red, yellow or orange, they would 

 photograph almost or quite black ; but as the tints wiiich they give 

 are not black, and yet sensibly darker than they appear in the teles- 

 cope, it follows that the true color must be a compound of blue, with 

 red or yellow ; it cannot be a compound of the three primary colors, 

 as that would be gray, which would photograph just as it appears ; 

 nor can it be the compound of red and blue, which is purple, 

 because that effects the photographs just like the grays ; conse- 

 quently the facts force upon us the conclusion that the true color ot 

 those so called " desert wastes" is green, as that is the only compound 

 left in the whole chromatic scale which would produce the eftects to 



