120 U. S. BUREAU OF FISHERIES 
The more technical aspects of drying will not be discussed here, nor 
will a review of the literature on drying (which is large) be taken up.® 
Much research has been carried out on air drying in connection with 
the chemical and allied industries and in the fruit and vegetable 
dehydrating field. Many of the papers deal with the reaction of 
various substances to varying drymg conditions and may include a 
discussion of the principles of air drying. Others discuss drier design, 
a subject treated but briefly in this article. Some experimenting on 
rather complete moisture removal has been done, but apparently no 
study has ever been made of partial dehydration of fish as applied to 
the sardine-canning industry. This problem will be shown to be 
somewhat different from more complete dehydration. 

Fic. 22.—Experimental drying equipment 
THE PROBLEM 
The problem with respect to partial dehydration of raw and 
steamed fish for canning as sardines is, first, to determine, by experi- 
ment, the behavior of the fish under different drying conditions. 
With these data in hand, and having determined just what the 
function of drying is in the different methods of preparing the fish 
and the extent to which it should be carried out, one will be able to 
apply that which is already known on air drying to improving and 
cheapening this important step. 

43 The technical side of air drying is thoroughly covered in the following papers and books: ‘The rate of 
drying solid materials.’””, By W. K. Lewis. Journal of Industrial and Engineering Chemistry, vol. 13, 
pp. 427-432. Easton, Pa., 1921. ‘‘The theory of atmospheric evaporation with special reference to com- 
partment driers.” By W.H.Carrier. Jbid., pp. 432-438. ‘‘The compartment drier.’?’ By W. H. Carrier 
and A. E. Stacey, jr. Jbid., pp. 438-447. ‘Tunnel driers.’”’ By Graham B. Ridley. JIbid., pp. 453-460. 
“High-temperature drying.’”’ By Burt S. Harrison. American Heating and Ventilating Engineers’ Guide 
for 1922, pp. 49-60. New York. ‘‘The temperature of evaporation.’”? By W.H. Carrier. JIbid., pp. 61-82. 
“Principles of chemical engineering.’’ By William H. Walker, Warren K. Lewis, and William H. 
McAdams. Chap. XVI. New York, 1923. ‘Industrial drying, the apparatus and how it works.”’ By 
Lucien Buck. Chemical and Metallurgical Engineering, vol. 29, pp. 626-631. New York, 1923. ‘Fan 
Engineering.” By W.H. Carrier. 2d ed. Buffalo, N. Y., 1925. 
