ASTRONOMY — HALS. 85 



Other Construction. 



Apart from the large amount of work done on the 60-inch mounting, 

 and the construction of the grinding and polishing machines for the 

 optical shop, the instrument shop has accomplished a great deal during 

 the year. The globe-measuring machine, after construction in its original 

 form, was completely remodeled, as already described. A large circular 

 dividing engine was also built and provided with a 36-inch circle by 

 Warner & Swasey, which is guaranteed to have no error greater than 2 

 seconds of arc. This engine will be used for dividing the fine circles of the 

 60-inch reflector. It has already been of service in dividing the circles of 

 the heliomicrometer, and for other purposes. The completion of the 

 5-foot spectroheliograph, and of the 18-foot Littrow spectrograph, used 

 with the Snow telescope, should also be mentioned. Electric heating 

 apparatus has also been made for the mirrors of the Snow telescope, and 

 a large amount of special apparatus for the spectroscopic laboratory on 

 Mount Wilson. The erecting house for the mounting of the 60-inch 

 reflector ; the wooden frame of the electric crane ; and the carpentry in 

 the rooms of the computing division, including the shelves and tables, 

 were the work of our men. A very large number of patterns have been 

 made in the pattern shop. 



The small amount of construction done by our workmen on Mount 

 Wilson includes the addition of a wing to the Monastery and the erection 

 of a concrete storehouse, adjoining the spectroscopic laboratory. A large 

 amount of brush was cut on the mountain as a further safeguard against 

 forest fires. 



Mount Wilson Road. 



Through the kind cooperation of Director D. T. MacDougal, of the 

 Department of Botanical Research, it has been possible to entrust the 

 superintendence of the important work of widening the new trail to Mr. 

 Godfrey Sykes, who is acting under the general direction and with the 

 active cooperation of Mr. Ritchey. At present about 120 men are em- 

 ployed, working in three gangs. Every effort is being made to hasten the 

 work, so as to avoid the delays and serious expense which might result if 

 it were greatly prolonged after the opening of the rainy season. It now 

 appears probable that the only work which will remain uncompleted at 

 that time will be the rock-blasting on the sides of Mount Harvard. It 

 is hoped that the repairs to the road that will undoubtedly be neces- 

 sitated by the winter rains can be completed within a short time in the 

 early spring, so that the heavy program of construction on Mount Wilson 

 planned for the summer of 1907 can be carried out. 



