260 



PROCEEDINGS OF THE AMERICAN ACADEMY 



TABLE X. 



The readiiijjs in the sixth column cannot be reduced to wave-lengths 

 directly, since they fall outside of the limits of Table VI, The curve 

 on wliich this table was based was accordingly prolonged, and a curve 

 drawn giving for large readings the corresponding wave-lengths. In 

 the columns of Table XI. these values are given for intervals of half a 

 turn of the micrometer screw. 



TABLE XL 



The readings in the fourth column of Table X. serve to test ihc 

 flexure of tlic spectroscope by showing whether the zero was the same 



