54 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1934 



toes. He also repeated and published measurements on phototropism 

 in oat coleoptiles. These measurements are of such extreme accuracy 

 in indicating the relations of sensitiveness of bending to wave length 

 that the curve seems to be accurate in much of its length to less than 2 

 percent. Dr. Johnston also carried through in the open sunlight a 

 series of experiments to determine the influence on wheat of modifying 

 the supply of carbon dioxide. The results are exceptionally striking 

 and will form a paper in the Smithsonian Miscellaneous Collections. 



Dr. Florence E. Meier continued experimental studies of the influ- 

 ence of different colored rays on the multiplication of the alga Sticho- 

 coccus bacillaris. Further check t^xperiments are contemplated. She 

 published results on the lethal action of ultraviolet rays on Chlorella 

 vulgaris. 



L. B. Clark made up many valuable designs of glass and electrical 

 appliances for all members of the staff and also for the staff of the 

 Astrophysical Observatory. His technical skill and wise counsel in 

 these fields were indispensable. 



Dr. F. S. Brackett, part-time consulting physicist, made progress 

 in preparing apparatus for absorption spectral investigations, and 

 designed therefor very ingenious devices. Much of his time, however, 

 was absorbed in the preparation of an important technical monograph 

 on radiation measurements, to be published under the auspices of the 

 National Research Council. Dr. Brackett's experience in such work 

 makes this contribution of extreme value. 



Respectfully submitted, 



C. G. Abbot, Director. 



The Secretary, 



Smithsonian Institution, 



