1 64 CARNEGIE INSTITUTION OF WASHINGTON. 



lent stone can be rendered easily accessible by the extension of roads 

 constructed for work now in progress. 



Numerous fallen trees on Mount Wilson, which are not yet 

 greatly decayed, will furnis'h an abundant supply of fire-wood for 

 many years to come. They can not be depended upon, however, to 

 yield any wood for building purposes, and as the living trees may not 

 be destroyed, all lumber must be taken to the summit of the mountain 

 from Pasadena. This raises the question of transportation over the 

 mountain trail — a matter of vital importance in constructing an obser- 

 vatory. The "Toll Road" or "New Trail." which extends from the 

 summit of the mountain to the foot of Eaton Canyon, is well adapted 

 for all ordinary packing with animals, though it is much too narrow 

 to permit wagons to pass over it. At present, all except the heaviest 

 articles are taken to the summit of the mountain by means of burros 

 and pack-mules, each of Which can carry a load ranging from 80 to 

 200 pounds. It is evident that transportation of building materials 

 by this means must be very slow and expensive, since the trail is 9 

 miles in length to the foot of Eaton Canyon, 6^ miles distant by road 

 from Pasadena. But, as compared with most mountains. Mount 

 Wilson is unusually accessible from cities, Pasadena being so close 

 at hand, and Los Angeles, with its large sources of supply, being 

 only 9 miles farther away. 



For transporting heavy castings and other similar articles, we 

 have found it necessary to construct a special four-wheel carriage, 

 2 feet in width. On this loads of a thousand pounds have been 

 taken to the summit without difificulty. By widening the trail 

 to 6 feet, the heaviest castings required for a solar observatory prob- 

 ably could be transported. 



WEATHER. 



So far as cloudiness is concerned, the records of the Weather 

 Bureau at Los Angeles are of comparatively little value for our 

 present purposes. The fog rolls in from the ocean night after 

 night, and sometimes hangs over Los Angeles throughout the day 

 during the winter season. But Mount Wilson reaches far above 

 this layer of clouds, and thus frequently enjoys sunshine when the 

 valley below is completely covered. Our daily percentage record 

 of cloudiness, beginning on April 18. 1904, may be found in the 

 following table. A dash signifies that no observation was made. 



There were many days which were cloudy at the time of observa- 

 tion, but nevertheless suitable at other hours for solar work. Add- 

 ing these to the record, it may be said that the actual number of days 



