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LITERATURE CITED. 
BEATTIE, JAMES H. 
1921. Tomatoes for canning and manufacturing. U. S. Dept. Agr., 
Farmers’ Bul. 1233, 20 p., 7 fig. 
HARVEY, R. B. 
1918. Hardening process in plants and developments from frost in- 
jury. Jn Jour. Agr. Research, v. 15, no. 2, p. 83-112, 3 fig., 
pl. 7-11, A(col.) Literature cited, p. 108-111. 
1919. Importance of epidermal coverings. Jn Bot. Gaz., v. 67, no. 5, 
p. 441-444, 2 fig. 
TAYLOR, GEORGE F. 
1920. Some improvements on the needle type thermocouple for low 
temperature work. Jn Jour. Ind. and Eng. Chem., v. 12, 
no. 8, p. 797-798, fig. 1. 
WriGHT, R. C., and Harvey, R. B. 
1921. The freezing point of potatoes as determined by the thermoelec- 
tric method. U. S. Dept. Agr. Bul. 895, 7 p., 1 fig. 
WricuHtT, R. C., and TAYLoR, GEORGE F. 
1921. Freezing injury to potatoes when undercooled. U. S. Dept. Agr. 
Bul. 916, 15 p., 1 fig., 1 pl. Literature cited, p. 15. 
[Youne, FLoyp DILLon ]. 
1920. Frost and the prevention of damage by it. U. S. Dept. Agr., 
Farmers’ Bul. 1096, 48 p., 24 fig. 
10 
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