DEPARTMENT OF BOTANICAL RESEARCH. 95 



EQUIPMENT. 



The developraent of facilities for control of temperatures has 

 included the construction of a glass compartment 12 by 20 feet, with 

 an attached work-room, at the Coastal Laboratory. An attached work- 

 room shelters the switchboards and current controls. Darkened 

 chambers for similar purposes have also been equipped in the main 

 building at the Coastal Laboratory and at the Desert Laboratory. 

 These features have already demonstrated their usefulness. 



The principal instrumental additions include a set of 12 auxographs 

 designed by the Director for the purpose of recording variations in vol- 

 imie accompanying growth, and for measuring the swelhng of colloids. 



A food-cage 30 by 60 feet, inclosed with wire netting, has been 

 constructed for growing solanums, to serv^e as food for the beetles used 

 in Professor Tower's experimental work in evolution. Other changes 

 in the equipment have consisted principally in minor replacements 

 and repairs and minor improvements in machines and apparatus 

 already on hand. 



FIELD WORK. 



The practical radius of action in the study and connotation of 

 natural conditions has now been extended 60 to 100 miles by improve- 

 ment in motor transportation. In addition to frequent excursions 

 to such distances, some detached field parties have been sent out 

 during the year. One party, accompanied by Dr. W. T. Hornaday, 

 of the New York Zoological Park, traversed the region southwest of 

 Tucson to the Ajo Mountains and north to Casa Grande in October 

 1915. A second party went northward through Arizona to the 

 Grand Canyon, eastward to the Painted Desert of the Little Colorado, 

 and southward by two different regions. A westward line was carried 

 across the drainage of the Colorado River, the Mohave Desert, and the 

 Coast Range to Carmel. The region between Tucson and the summit 

 of the Santa Catalina Mountains is covered frequently. Workers 

 at the Desert Laboratory easily visit the points of interest in an area 

 of about 5,000 square miles, and material from this area is readily 

 procurable for experimental purposes. 



