OX THE COMPLEXION. 



reasonal >ly be inferred that the moon has no influence whatever 

 in this case. 



Among the maxims of Pliny we find that grapes should be 

 dried by night at new moon, and by day at full moon. 



Wheu the moon is new it is below the horizon during the night, 

 and above it during the day ; and when it is full it is above the 

 horizon during the night, and below it during the day. The 

 maxim of Pliny, therefore, is equivalent to a condition requiring 

 that the grapes should be dried when the moon is below the 

 horizon. It is evident that the absence of the moon is not 

 required in this case in consequence of any effect which her light 

 might produce if she were present ; for when the moon is new she 

 affords no light, even when in the firmament, the illuminated 

 side being turned from the earth. If the maxim be founded upon 

 any reason, it must, therefore, either be on some influence which 

 the moon is supposed to produce when present, independent 

 of her light (the absence of which influence is desired), or it may 

 be that she may be supposed to transmit some effect through the 

 solid mass of the earth when on the other side of it which she is 

 incapable of producicg without its intervention. The maxim is 

 probably as absurd and groundless as the other effects imputed to 

 the moon. 



5. Supposed Lunar Influence on the Complexion. It is a prevalent 

 popular notion in some parts of Europe, that the moon's light is 

 attended with the effect of darkening the complexion. 



That light has an effect upon the colour of material substances 

 is a fact well known in physics and in the arts. The process of 

 bleaching by exposure to the sun is an obvious example of this 

 class of facts. Vegetables and flowers which grow in a situation 

 excluded from the light of the sun are different in colour from 

 those which have been exposed to its influence. The most 

 striking instance, however, of the effect of certain rays of solar 

 light in blackening a light -coloured substance, is afforded by 

 chloride of silver, which is a white substance, but which imme- 

 diately becomes black when acted upon by the rays near the 

 violet extremity of the spectrum. This substance, however, 

 highly susceptible as it is of having its colour affected by light, 

 is, nevertheless, found not to be changed in any sensible degree 

 when exposed to the light of the moon, even when that light is 

 condensed by the most powerful burning lenses. It would seem, 

 therefore, that as far as any analogy can be derived from the qua- 

 lities of this substance, the popular impression of the influence of 

 the moon's rays in blackening the skin receives no support. 



M. Arago (who generally inclined to favour rather than 

 oppose prevailing popular opinions), thought it possible that 



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