696 



This curve therefore appears to possess the peculiarity, that the 

 rotation at first rapidly increases for greater wave-lengths, but 

 decreases then very steeply in the vicinity of tiie absorption-band, 

 to assume the opposite algebraic sign at circa 6260 A.U. The right- 

 handed rotation now reached, shows a minimum at about 6400 A.U. , 

 and decreases at first rapidly, afterwards more slowly, so that the 



