Plate Glass Company of Paris, has been thoroughly 

 tested by the most exacting methods and is now 

 being polished and figured in our optical shop. 



To carry such a mirror with perfect freedom 

 from flexure and with the high precision which 

 modern photographic methods demand, a tele- 

 scope mounting of exceptional size is required. 



FIG. 62. Erecting Steel Building for loo-inch Reflector. 



This is now under construction at the Fore River 

 Ship Yard in Quincy, Massachusetts, where ma- 

 chinery used for building the largest battleships 

 is available. The smaller parts of the mounting, 

 and others requiring special accuracy of fitting, 

 are being made in our own machine-shop in 

 Pasadena. 



