BOTANICAL LABORATORY IN THE DESERT. 333 



the volcanic hills, the dark color of the ground affords very appre- 

 ciable relief. 



The general Laboratory is furnished with individual tables, a gen- 

 eral work table and two sources of water supply. It should be noted 

 that, although two miles fiom town and upon an elevation of 300 feet 

 above it. there is abundant water supply. It is to the enlightened in- 

 terest of the citizens of Tucson that this convenience, as well as the 

 electrical connections, acreage and roadways, are to be credited. The 

 immediate source of water is a 300-gallon tanlc, supplied from a pump- 

 ing station at the foot of Sentinel Hill, which stands immediately to 

 the southeast of the laboratory. 



The General Laboratory. 



Adjoining the general laboratory is the stock room, liberally supplied 

 with the necessities for work. This leads into a photographic dark 

 room, with water supply, ventilation and a cement floor, and which 

 may be used as a physiological dark room, with constant temperature. 



The library, which adjoins the stock room, though at present small, 

 contains a carefully selected lot of periodicals and books, the latter 

 chosen with special reference to their bearing upon desert exploration 

 and vegetation. From the library one enters the office of the resi- 

 dent officer, Dr. W. A. Cannon, whose generous treatment and constant 

 sympathy, coupled with the material opportunities afforded, leave little 

 to be desired. 



The view commanded from the laboratory site is a panorama of 



