30 CARNEGIE INSTITUTION OF WASHINGTON. 



The optical parts of the 6o-inch reflecting telescope have been made ready 

 for mounting, but owing to the labor strikes at San Francisco the completion 

 of the dome for the telescope may delay its erection until the spring of 1908. 



The novel tower telescopic apparatus, part of which is above and part of 

 which is belov/ the ground level, has been substantially completed. This 

 consists essentially of a vertical telescope with a 12-inch objective and 60 feet 

 focal length in combination with a Littrow grating spectrograph of 30 feet 

 focal length, thus furnishing a powerful component in the battery of instru- 

 ments for direct observations of the sun. 



Preparations for grinding, figuring, and testing the 1 00-inch reflector, 

 whose construction, as explained in my preceding report, was rendered pos- 

 sible by the gift of Mr. J. D. Hooker, have likewise gone forward. A fire- 

 proof building for this v/ork has been constructed and the necessary grinding- 

 machine is nearing completion. In the meantime it is expected that the Plate 

 Glass Company of St. Gobain, France, will soon have the large disk for this 

 reflector ready for shipment, since it was successfully cast on August 28th 

 last. In the rough this disk will weigh about 4.5 tons. 



Simultaneously with these varied works of construction, daily photohelio- 

 graphic and spectroheliographic observations have been made by aid of the 

 Snow Telescope. Daily studies of the sun and sun-spot spectra have supple- 

 mented these observations, and to them have been added pyrheliometric and 

 solar magnetic measurements, along with numerous laboratory investigations 

 bearing directly on the physical properties of the sun. 



The year for this department has been one of varied activities and one 



specially fruitful in the quantity and quality of the results attained. The 



operations have embraced magnetic surveys of the North 



Department of Terres- Pacific Ocean; surveys on land in Alaska, Bermuda 

 trial Magncttsm. ' ■' ' 



Islands, Canada, Central America, China, Mexico, and 



South Pacific Islands ; and office work combined with special observational 



studies at Washington, D. C. 



The ship Galilee, used in the magnetic survey of the Pacific, started from 

 San Diego, California, on her third cruise on December 22, 1906. Sailing 

 by way of the Marquesas Islands, Samoan Islands, and Yap Island, she 

 arrived at Shanghai, May 8, 1907. From this point she sailed east to Mid- 

 way Islands, and thence to Sitka, where she arrived July 14, 1907. Leaving 

 Sitka, August 10, she started on a cruise to the South Pacific by way of 

 Honolulu, Jaluit, Marshall Islands, and New Zealand; returning thence by 

 way of Callao to San Francisco. It is expected that she will complete this 

 cruise about May i, 1908, when she will be returned to her owners. 



Up to September i, 1907, the Galilee had traversed nearly 50,000 miles in 

 the Pacific Ocean along courses where few magnetic observations have been 

 made hitherto. Complete measurements of magnetic declination, dip, and 



