208 EXPERIMENT STATION RECORD. [Vol.38 



eqiiipment for evaporators, p:iring machines, bleachors, slicers, etc.; plans of 

 evaporators ; the curing room ; and color, uniformity, cut, etc., of the finished 

 product. 



Canned foods, A. W. Bitting {U. S. Dept. Com., Bur. Foreifjn and Dom. Com., 

 Misc. tier.. No. SJf {1911), pp. 79, figs. 39). — This bulletin describes and discusses 

 modern processes of commercial canning in the United States, the general sys- 

 tem of grading, and products available for export. 



Home and farm canning, W. V. Cruess {California Hta. Circ. 158, reo. ed. 

 {1917), pp. 32, figs. 10).— In this revision (E. S. R., 36, p. 509), special direc- 

 tions for meats and some notes on ptomaine and botulinus poisoning and on new 

 methods of sterilizing fruits and vegetables have been added. 



For vegetables low in acidity, the addition of lemon juice and sterilization 

 at 212° F. was found to sterilize the material completely, but not in any way 

 to be injurious to its flavor or texture. Since heating fruits at 212° always 

 changes more or less tlie flavor, texture, and appearance, experiments were 

 carried out to determine the lowest temperature at which complete sterilization 

 was elfocted. Temperatures of from 165 to 175° were found to be sufllcient 

 and to yield most satisfactory products. 



A German substitute for jute {Agr. Jour. India, 12 {1911), No. 1, pp. 159, 

 160). — A material designated as " textilose " made from paper pulp which has 

 passed through machines and been spun into thread or cord preparatory to weav- 

 ing into a tough cloth is briefly noted. The material is reported as possessing 

 remarkable wearing qualities and to be a creditable substitute for the natural 

 fiber, though higher priced. 



METEOROLOGY. 



Relation between temperature and crops, D. A. Sp:eley {Abs. in U. S. Mo. 

 Weather Rev., 45 {1911), No. 1, pp. 354-359, figs. 3).— Previous attempts to de- 

 termine the relation between weather and crop production are reviewed, espe- 

 cially with reference to the methods employed. 



Observations at East Lansing, aiich., during 1915 and 1916 on the tem- 

 perature of the plant itself under varying atmospheric conditions are recorded. 

 These show that the plant is much warmer than the air when bathed in sun- 

 shine, the excess in clear weather averaging about 15°, in partly cloudy 

 weather, 10°, and in cloudy weather, less than 1° F. " Curves expressing 

 plant growth rates and plant temperatures show parallelisms more decided than 

 other temperatures observed, including maximum and mean air temperatures, 

 soil temperatures, and readings of the ' black-bulb in vacuo.' A test of the 

 number of heat units required to cause a cherry tree to blossom in the green- 

 house and out of doors shows remarkably close results when plant temperatures 

 are considered, but a consideration of air temperatures alone gives a wide 

 variation. 



"A formula is evolved for determining the effectiveness of air temperature in 

 promoting crop development, as follows : 



T=<+15C+10P, 

 t being the sum of maximum temperatures above 42° during a certain period, 

 after that amount has been subtracted from each temperature, C being the num- 

 ber of clear, and P the number of partly cloudy days during the period." 



A list of references to literature bearing on the subject is given. 



Killing frost and length of growing season in various sections of Ken- 

 tucky, F. J. Walz {Kentucky Sta. Circ. 19 {1911), pp. 121-132, figs. 4; U. S. 

 Mo. Weather Rev., 45 {1911), No. 1, pp. 3J,8-353, figs. //).— This paper sum- 

 marizes and presents in tables and charts the results of a study of the dates of 



