768 
Journal of Agricultural Research voi. xxvii, No. 10 
from similar fruit colored in the usual way with kerosene stoves. How¬ 
ever, attempts to isolate ethylene from stove gas were unsuccessful. 
When mixed with air in varying proportions by volume, concentra¬ 
tions of ethylene down to i to 200,000 colored lemons in 5 to 8 days. 
Concentration down to 1 to 2,000,000 required 6 to 10 days. The lowest 
concentration tried (1 to 5,000,000) required about 14 days, indicating 
that this concentration represents the highest dilution at which the rate 
of coloring is markedly influenced. High concentrations appear to retard 
coloring, since 80 per cent ethylene for 7 days gave only slight coloring. 
Absence of oxygen prevented coloration of the fruit by ethylene. 
Coloration was not measurably hastened by ethylene at a temperature 
of 45 0 F., but the rate of coloring increased with increasing temperatures, 
from 57 0 to 82°. A reduction in rate, however, was observed at 93°. 
Both ethylene and stove gas increased the rate of respiration of lemons. 
The carbon dioxid output was increased about 150 to 250 per cent. 
Ethylene is now a commcercial article and can be bought as a com¬ 
pressed gas in steel cylinders. Gas in measured quantities may be released 
from the cylinder in a convenient manner and brought in contact with the 
fruit by use of an apparatus devised for the purpose. 
The effect upon green lemons of many other substances, including 
carbon monoxid, acetylene, methyl chlorid, formaldehyde, acetalde¬ 
hyde, pyridin, amyl acetate, and chlorin, was tested. 
ACKNOWLEDGMENTS 
The writer wishes to express his appreciation of the cooperation given 
by the Lemon Men's Club of Southern California, which furnished all of 
the fruit and part of the equipment necessary for carrying on the experi¬ 
ments, and by the Whittier Citrus Association*of Whittier, Calif., which 
granted the exclusive use of three large fruit storage rooms. Grateful 
acknowledgement is also made of the hearty cooperation of L. A. 
Brundige, and of his assistants, M. H. Wood and B. B. Clark, at the 
Whittier Citrus Association packing house. Finally, the advice and 
suggestions of E. M. Chace, chemist in charge, Laboratory of Fruit and 
Vegetable Chemistry, Bureau of Plant Industry, United States Depart¬ 
ment of Agriculture, who inaugurated and supervised the experiments,, 
are acknowledged. 
literature CITED 
(1) Anonymous. 
1923. poisoning by illuminating gas. In Nature, v. hi, p. 293-295. 
(2) Burrell, G. A., and Gauger, A. W. 
1919. VITIATION OP GARAGE AIR BY AUTOMOBILE EXHAUST GASES. In U. S„ 
Dept. Interior, Bur. Mines Tech. Paper 216, 12 p. 
(3) Curme, G. O., Jr. 
1921. sources and uses of ethylene and propylene. In Chem. and Met. 
Engin., v. 25, p. 907-909. 
(4) Denig, Fred. 
1921. pyrolysis of some hydrocarbons. In Chem. and Met. Engin., v. 25,. 
P- 751 - 753 - 
(5) Dennis, L. M. 
1913. gas analysis. 434 p., no fig. New York. 
