55 



worm-gear (when mounted in place on the polar 

 axis), and the construction of the driving-clock, 

 was done by our own mechanicians. A necessary 

 part of the undertaking was the building of a 

 mountain road over 9 miles long, the transporta- 

 tion of the telescope and the steel building with 

 its revolving dome to the summit, and their erec- 

 tion by our construction corps. 



FIG. 41. Great Cluster in Hercules. 



Five years of work with this telescope have 

 brought out all of its admirable qualities and pro- 

 vided a rich store of photographs for the study of 

 stellar evolution. These are of the most varied 

 character, including star clusters (showing in one 

 case some 30,000 stars), nebulae, stellar spectra, 

 and occasionally the moon, planets, and comets, 

 though the three latter classes of objects are not 

 included in our present scheme of research. 



