On the Magnetic Influence of the Lunar Spectrum. i:\ 



placed in the blue rays ; the head in the red rays. 2. The 

 point was placed in the extreme violet rays ; the head in the 

 dark space beyond the violet rays. 3. The needle was placed 

 longitudinally in the blue or violet rays. 4. It was also placed 

 longitudinally in the red rays. The change however was 

 effected more rapidly when the influence of the blue or violet 

 rays acted on the needle, than when it was exposed to the 

 red rays, but in all cases its head pointed to the north, al- 

 though it had previously pointed to the south. 



6. Several subsequent experiments proved that the needles 

 so acted upon, retained their newly acquired magnetic pro- 

 perties, for twenty-four hours at least, after they had been 

 submitted to the power of the refracted solar rays. But it is 

 evident that this change of the poles was a phaenomenon in- 

 dicating some alteration in the relations of reciprocity between 

 the previously existing magnetic properties of the needle and 

 those of the earth. 



7. As a series of inferential arguments had already induced 

 the conclusion, that the magnetizing influence in all cases can- 

 not be a gravitating or attractive force, but one which only 

 interferes with, or controls that force ; and that it is in some 

 way connected with the production of light — although it may 

 prevail where there is no illuminating process — I imagined 

 that by making experiments upon the lunar instead of the 

 solar beam, it would be possible to separate the cause of the 

 illuminating property, from all those calorific and gravitating 

 influences which are the accompaniments of light in the sun- 

 beam. 



8. The reflected moon-beam is the manifestation of an oc- 

 casional and variable influence, acting within that region of 

 space between the earth and the moon, which is the medium 

 of a direct gravitating force : this force has nearly the same 

 intensity at all times, due allowances being made lor the ellip- 

 tical character of the lunar orbit. But as regards the reflec- 

 tion of the solar light from the moon's surface, it is an indi- 

 rect and borrowed influence, which is at its climax in rela- 

 tion to the earth when the moon is full, but altogether null 

 when she is new. 



9. It must also be remembered, that when the moon is full 

 the most delicate experiments have not detected heat in her 

 rays ; therefore it may be demonstrated, that the astronomi- 

 cally reflected light of the sun's rays is separated from those 

 rays in his direct beam, which evolve heat to a greater or less 

 extent, in the portion of the earth's surface on which it shines; 

 and this method of considering iiidirect or reflected light in 

 relation to the moon-beam, enables us to treat it, or its causcj 



