414 EXPERIMENT STATION RECORD. [Vol. 38 



variation in tiie composition of the ether extract of silage, depending upon 

 changes in the sample itself on standing and upon the drying operations em- 

 ployed. Further studies are being made to ascertain the causes of such 

 variation. 



A constant temperature and humidity room for the testing of paper, tex- 

 tiles, etc., F. P. Veitch and B. O. Eeed {Jour. Indus, and Engin. Chem., 10 

 (1918), No. 1, pp. 38-J^Jf, fujs. 6). — This article describes the specially constructed 

 and automatically controlled constant-temperature and humidity room at the 

 Bureau of Chemistry, U. S. Department of Agriculture. The room is used in 

 the testing of paper, but it is pointed out that the control of humidity is of 

 importance in many industrial lines, and is being applied to the ripening of 

 fruit, curing of cheese, drying of lumber, etc. 



A method for determining the absorbency of paper, E. O. Reed {Jour, Indus, 

 and Engin. Chem., 10 (1918), No. 1, pp. U--i7). 



The cost of producing maple products in 1912 and 1913, C. J. Feink (Ver- 

 mont Sta. Bui. 203 (1917), pp. 17-24, fi&s. 3).— The author has collected from 

 a number of sugar producers in Vermont data concerning the cost of production 

 of maple products and prices received for the same during the seasons of 1912 

 and 1913 and has arranged the data in the form of tables and graphs. 



The relation between total cost per pound and production per bucket is con- 

 sidered significant. A decrease in the cost per pound coincides with increased 

 yield per bucket. The graph of this relationship gives a general idea of the 

 probable cost of a pound of sugar for any given average bucket production. 

 A 1-lb. per bucket yield showed a manufacturing cost of 11 cts. for 1 lb. of 

 sugar while a 3-lb. per bucket yield reduced the cost to 7.5 cts. per pound. 



Vinegar from waste fruits, W. V. Ceuess (California Sta. Bui. 287 (1917), 

 pp. 169-184, figs. 11). — This bulletin describes the necessary apparatus and 

 procedures for the alcoholic fermentation, acetic acid fermentation, and clarifi- 

 cation and filtration of the product in the conversion of waste fruit juices into 

 vinegar. Brief notes on vinegar diseases are included. 



The canning industry. — Some accomplishments and opportunities along 

 technical lines, H. A. Baker (Jour. Indus, and Engin. Chem., 10 (1918), No. 1, 

 pp. 69-71). — This includes a brief history of the canning industry in the United 

 States, an outline of some of the problems confronting the industry and their 

 solution, and suggestions as to further possibilities of conservation by the dis- 

 covery of methods of utilizing waste products. The importance of chemists in 

 the industry is emphasized. 



METEOROLOGY. 



Climatic control of cropping systems and farm operations, J. F. Voorhees 

 (Proc. 2. Pan Amer. Sci. Cong., 1915-16, vol. 2, pp. 127-1S2) .—T\\q author main- 

 tains on the basis of his study of conditions in Tennessee that all successful 

 cropping systems must be so planned that they make use of all favorable climatic 

 conditions. " To do this to the best advantage the time required for each crop 

 to mature under any given conditions nmst be known. The eifect of variations 

 in heat intensity upon the various stages of the life history of insect pests 

 should also be known." The discussion is confined " to the broad and com- 

 paratively unchanging features of climate and disregards the more change- 

 able features of weather . . . [such asl the average conditions of temperature, 

 rainfall, and growing season at a given place for a long period of years." These 

 are considered with reference to continuous cropping, two-crop, and one-crop 

 .systems of farming. 



A marked correlation between intensity of temperature and time required 

 for crops to mature was shown in studies carried on by the author in coopera- 



