.1 NEW METHOD OF RESEARCH. 



J 3 



ever, that the possibilities of the new method were much greater than 

 had been indicated by the work so far accomplished. It seemed certain 

 that our knowledge of the finer details of the calcium clouds would be 

 greatly increased if provision could be made for photographing a much 

 larger solar imago with a spectroheliograph of improved design. And 



Fig. 5.— The Rumford. Spectroheliograph attached to the Yerkes Telescope. 



it was furthermore evident that other applications of the instrument, 

 involving the use of different spectral lines, and the employment of 

 principles which had not entered in the Kenwood work, might reason- 

 ably be hoped for. 



The construction of the great forty-inch telescope of the Yerkes 



