8o 



which seeks to express a wide range of phenomena 

 under a single mathematical law. As already in- 

 dicated, the policy of the Observatory is to enlist 

 in this endeavor the ablest mathematical astron- 

 omers and physicists, of Europe or America, whose 

 cooperation can be secured. 



Fie,. 56. Large Measuring MachiiiL- for Solar Spectra 

 INSTRUMENT AND OPTICAL SHOPS. 



The equipment of the instrument and optical 

 shops has grown steadily with the demands of the 

 work in progress. Our requirements range from 

 the accurate cutting of the teeth of worm-gears 14 

 feet in diameter dow r n to the smallest attachments 

 of microscopes, galvanometers, and other delicate 



