16 CARNEGIE INSTITUTION OF WASHINGTON. 



cumstance and on account of the fact that the departments on the 

 average, as well as the present administration, will have completed 

 a first decade in the Institution's history a year hence, it seems 

 desirable to reserve any more elaborate summaries of work accom- 

 plished and now under way, whether of departments or of research 

 associates, until that time. Accordingly this section of the present 

 report is limited to something less than the usual extent. 



Studies of the Salton Sea,* carried on during the past seven years 



by this department in collaboration with a number of contributing 



, specialists, have been brought together during the 



Department of ^ . ' . j xi x--i iirT^u 



Botanical year m a volume now m press under the title ihe 

 Research. g^lton Sea: A study of the geography, the geology, 

 the floristics, and the ecology of a desert basin," as publication No. 

 193. A great number of interesting questions in geography, geology, 

 botany, chemistry, micro-biology, plant physiology, climatology, etc., 

 are discussed in this volume. Of these, an instructive abstract is 

 given by the Director in his current report. 



Among many researches carried on by the Director, mention may 

 be made of his cultivation of second and third generations of mutants 

 arising from ovarial treatments of plants and resulting in further note- 

 worthy morphological and physiological departures from the original 

 parent stocks. Of members of the departmental staff. Dr. Cannon 

 has extended his fruitful studies of root systems of desert plants to 

 include the corresponding characteristics of trees in the coastal climate 

 of California and to the problem of treelessness in prairie regions. 

 Dr. Forrest Shreve has given special attention to the factors involved 

 in the transpiration of rain-forest plants and to the effects of moun- 

 tain slopes and climatic conditions varying with altitudes and with 

 exposures. Dr. Spoehr has continued his investigations of the action 

 of light and heat in producing chemical changes in plant organisms, 

 giving promise thus of important advances in the newer field of 

 phytochemistry and photolysis. 



Several collaborators have contributed to the varied work of the 

 department during the year. Sections of the Director's report are 

 thus devoted to accounts of the further experiments of Professor 

 W. L. Tower on the evolution of chrysomelid beetles, for which facili- 

 ties are provided at the Desert Laboratory ; to the physical studies of 



♦Often by earlier writers called Cahuilla Basin, more frequently called Salton Sink, 

 and now called Blake Sea, in honor of Professor Blake, who, as geologist of the 

 Williamson survey of 1853, first accurately interpreted this remarkable depression 

 below sea-level. 



