DEPARTMENT OF BOTANICAL RESEARCH. 63 



The New Chemical Laboratory at Carmel, by H. A. Spoehr. 



In March of 1921 work was begun on the construction of the new 

 laboratory at Carmel. The apparatus and equipment of the chemical 

 laboratory at Tucson was packed and shipped to Carmel and in 

 August the new laboratory was ready for occupancy. This building 

 is a single-story structure, 42 bj^ 32 feet, built of brick, with partitions 

 of the same material and a concrete basement. The latter is entirely 

 below ground and contains two constant-temperature rooms to the 

 construction of which special attention was devoted in order to secure 

 perfect insulation. Floors, inside partitions, and doors are insulated 

 by means of hair-matting, a dead-air space, and mineral wool. The 

 upper floor contains a chemical laboratory 23 by 18 feet, a room for 

 physiological work, with water thermostats, etc., 20 by 15 feet, an 

 office 16 by 13 feet, and a machine and store room 21 bj^ 11 feet. A 

 glass-inclosed porch 12 by 12 feet provides excellent outside working 

 space. The entire building is equipped with water, gas, vacuum, 

 compressed air, and numerous receptacles for 110 and 220 volt alter- 

 nating-current electricity. A 3.5 k. w. motor generator set provides 

 direct current. The gas is produced by a de Laitte gas-machine of 

 320 cubic feet per hour capacity^ placed in a separate small building. 



Anaerobic Experiments with Argon, by W. A. Cannon and E. E. Free. 



In the annual reports of this Department for 1919 and 1920 there 

 were described experiments in which helium was used, instead of the 

 more usual nitrogen, as the diluting gas in experiments with the growth 

 of roots and other plant parts under partial anaerobic conditions. 

 It was discovered that nitrogen and helium did not behave exactly 

 alike, the amount of oxygen necessary for growth being somewhat 

 greater when the diluting gas was nitrogen than when this was helium. 

 It was suggested that the explanation of these effects might lie in 

 the greater rapidity of diffusion of oxygen through helium than through 

 nitrogen. 



In order to test this diffusional hypothesis, experiments have now 

 been made in which argon was used as the diluting gas; the results 

 are the same as those with nitrogen. The same concentration of 

 oxygen is necessary in each case for a given plant activity. It is 

 believed that this result furnishes strong confirmation of the diffu- 

 sional hjTDothesis, the rate of diffusion of oxygen through argon being 

 practically the same as through nitrogen, while the argon is as free 

 from suspicion of direct chemical activity as is helium. 



Tests in which hydrogen was used as the diluting gas indicate that 

 this gas behaves almost the same as does helium. This fact is also 

 confirmatory of the diffusional hypothesis, but the tests with hydrogen 

 are not sufficiently numerous to constitute important evidence. 



