232 CARNEGIE INSTITUTION OF WASHINGTON. 



since then Miss Coral Wolfe has been in charge. The accessions of 

 bound volumes during the year number 580, of which 285 were 

 acquired by purchase, 266 by binding, and 29 by gift. The total 

 number of bound volumes now in the library is 3,130. 



CONSTRUCTION DIVISION. 



The fact that the 100-inch disk would prove suitable for use in the 

 telescope, which was determined soon after the completion of the last 

 annual report, has led to a great increase of activity in the Construc- 

 tion Division. As long as it remained uncertain whether a suitable 

 glass disk for this telescope could be obtained it did not appear to be 

 wise to proceed with the construction of the dome and mounting; 

 but when the uncertainty was removed work was pushed forward 

 in all departments. The Director and the Assistant Director have 

 remained in charge of all construction, and have given much atten- 

 tion to the problems of design and execution of work. Mr. Ritchey 

 has gone forward with the work on the 100-inch mirror and the 

 60-inch plane mirror for testing the former. Since the resignation of 

 Mr. Drew on March 1, Mr. Pease has been in charge of all work of 

 the drafting department, including the design of the 100-inch mount- 

 ing, to which he has devoted most of his attention. Mr. Jones has 

 remained in charge of building construction in Pasadena and on 

 Mount Wilson, and Mr. Ayers has continued to superintend the work 

 of the instrument shop. Dr. Anderson and Mr. Jacomini, aided 

 by the instrument shop, have carried forward the work on the ruling- 

 machine so rapidly that it is now nearly ready for a definitive test. 



The problems connected with the construction and erection of the 

 100-inch telescope mounting and dome and the large auxiliary instru- 

 ments required in its use have made two serious demands upon the 

 observatory equipment. The first of these was for a more rapid 

 means of transportation of large amounts of heavy material over the 

 Mount Wilson road. The second was for larger machine tools with 

 which to construct such portions of the telescope mounting, driving 

 mechanism, and instrumental equipment as could be made to the 

 best advantage in the Observatory shops. Much careful study was 

 given to the question of meeting these two requirements. 



MOUNTAIN TRANSPORTATION. 



The experience of the Pasadena and Mount Wilson Toll Road 

 Company during the winter of 1912-13 had shown that motor trucks 

 could be operated successfully over the 9-mile road leading to the 

 summit of the mountain, and in March of this year a 1-ton truck 

 was purchased by the Observatory. This was followed in April by 

 the purchase of a similar truck of 3 tons capacity. Both trucks are 

 provided with excess water capacity to guard against overheating 



