90 CARNEGIE INSTITUTION 



should control at least one of these wells and its immediate water- 

 shed. 



It is not known how difficult it would be to obtain a large supply 

 of water at any other place near the summit of Mount Wilson. It 

 is certain that wells or tunnels at many places w T ould prove failures, 

 as did the first one that was designed to furnish a supply of water 

 for Martin's camp. Martin's camp is, in an air line, about half a 

 mile south of the summit, and 700 or 800 feet lower. It is now 

 supplied by a tunnel on the west side of the mountain at a distance 

 of perhaps 500 feet in altitude below the summit. It is possible 

 that the resources of this tunnel might be materially increased by 

 extending it further into the mountain, or by running drifts parallel 

 to the mountain side. This, however, is by no means certain. The 

 result of further tunneling would depend almost entirely upon the 

 character and arrangement of the strata encountered in making 

 these extensions, and what these would be in a granite mountain 

 densely covered with brush is not easily foretold. 



As it stands today, the tunnel that supplies Martin's camp does 

 not seem to afford a sufficient supply of water for a large commu- 

 nity, such as might eventually grow up around an important observa- 

 tory, and it certainly would not furnish the abundant supply that 

 would enable water to be used extensively for irrigation, which 

 would be necessary, for a time at least, if an attempt were made to 

 clothe the barren slides with a covering of chaparral. The greater 

 distance of the present tunnel below the summit as compared with 

 the wells at Strain's camp is a forceful argument in favor of the 

 latter. 



An undulating ridge connects Mount Wilson with San Gabriel 

 peak. Upon this ridge, at a distance of perhaps half a mile from 

 the Casino, is a summit locally known as Alta, which rises about 

 60 feet higher than Mount Wilson itself. Alta is not of large 

 dimensions. If an observatory were placed upon Mount Wilson it 

 would be the most favorable site available for the storage of water. 

 The pressure obtained from a reservoir placed here would not be 

 very great, but would be enough to make it of extreme importance 

 as a protection against fires and as a distributing center, etc. 



While in southern California, from April 17 to July 19 (with the 

 exception of the interval from July 8 to 16, when I was in Arizona), 

 I watched the drift of ocean fog over the land in reference to its 

 bearing upon the height at which an observatory would have to be 

 placed in order to be above its prevailing higher levels. 



