42 On the Magnetic Influence of the Lunar Spectrum, 



as an influence wholly distinct from the gravitating lunar 

 force which mainly occasions the rise and fall of the tides, as 

 well as from those calorific qualities which accompany the 

 direct light of the sun. 



10. It is evident, that the phsenomenon which we term 

 light, can only be a relation to an animal sense of perception , 

 or to a seeing organ in an animal body, which is affected in 

 a peculiar manner by some reciprocal influence acting be- 

 tween the organ and the object perceived. But the influence 

 of solar or lunar light, thus made manifest to one of our 

 senses, must be attfibuted to some real property direct or 

 reflected of the sun or moon ; for illumination in the case of 

 the moon-beam is evidence in favour of the existence of some 

 force derived from the sun, which is separated from the heat- 

 ing and gravitating forces by the process of reflexion. Hence, 

 supposing a magnetic influence to be the force which pro- 

 duces light when it acts upon our organs of vision, we are justi- 

 fied in the speculation that this result is not the onli/ conse- 

 quence of its prevailing in space to such an extent, as to 

 enable us to perceive the immensely distant fixed stars. 



11. It becomes, therefore, an experiment of the first im- 

 portance, to examine whether the reflexion of the sun's light 

 from another heavenly body, when it is divested of those 

 heating and gravitating influences which always accompany 

 it in the solar beam, is capable of occasioning peculiar mag- 

 netic phsenomena on the earth's surface : — not only was I pre- 

 pared for some such development, but for the manifestation of 

 a much higher and more sublimed influence than that dis- 

 covered in the above-mentioned experiments on the solar 

 spectrum. 



12. When the first prismatic observation was made with 

 the lunar instead of the solar rays, the moon was nearly full, 

 and the sun had been for some time below the horizon ; but 

 on a subsequent occasion it was repeated an hour before sun- 

 set, four days before full moon, with great care and accuracy; 

 and as the interposition of glass had already been found to 

 ofler no impediment to the magnetizing influence of the solar 

 beam, I was enabled to make my observations in a well- 

 closed room, and to prevent any trifling currents of air from 

 acting upon the surface of the water or from moving the float- 

 ing needle. 



13. The presence of day-light, as I expected, did not dimi- 

 nish, or in any way interfere with, the lunar influence, although 

 it rendered the experiment more difficult, because it hindered 

 me from seeing the prismatic image of the moon upon the 

 table, and from determining the suitable position in which the 



