4 BULLETIN 764, U. S. DEPARTMENT OF AGRICULTURE. 
the effect of its relative moisture content immediately becomes 
evident. Corn with a low moisture content requires a much longer 
time to reach that stage designated as ‘‘hot” or to become discolored 
or ‘‘damaged” by the process of heating, than corn with a high 
moisture content, while corn with a high moisture content will heat, 
become discolored, and lose weight by evaporation quickly, and the 
processes of deterioration are accelerated with each additional per 
cent of moisture much more rapidly than the proportionate increase 
in the moisture content. When corn of a low moisture content is 
found in a heating condition, it can ordinarily be restored to a cool 
condition with but a slight amount of handling and ventilating and 
without much, if any, loss in value through discoloration, while corn 
with a high moisture content, when heated in any considerable bulk, 
quickly becomes badly discolored and damaged and is restored to a 
cool condition with great difficulty and a great amount of handling 
only with more or less damage to its quality and a corresponding loss 
in value. 
It will be noted from the following charts and tables that many of 
the samples showed a higher moisture content at the time of discharge 
in Europe than the corn had at the time of loading. It is not thought 
possible under ordinary conditions of ocean transportation for corn or 
other grain, confined as it is in the holds of ships, to take on moisture 
from the air, as grain from semiarid regions is said to do when other- 
wise transported to more humid regions. This is especially true when 
the moisture content of the corn as shipped is high. There are two 
means by which the moisture content in any part or the whole of the 
ship’s corn cargo may be increased during transportation: (1) 
Transfer of moisture by air currents caused by changes in temperature, 
and (2) by chemical changes within the corn kernel. As to the first 
means, corn containing excessive moisture and situated so that the 
moisture can escape when subjected to heat, will give off moisture and 
become drier. The moisture thus given off in a ship’s hold, in case 
the temperatures in the hold are not uniform, finds its way to the 
usual air space above the corn and under the deck, passing thence as 
water to other parts of the hold where it condenses on the cooler corn, 
the cooler deck, and the sides of the ship. This process, augmented 
as time goes on by the second means, may increase considerably the 
moisture content of the corn in some portions of the hold or cargo. 
The second means by which the moisture content of the corn may be 
increased is by the change in the chemical composition of the kernel, 
the effect of which is more evident in corn that is heating badly. Con- 
ditions of temperature and moisture may be favorable in some part of 
the cargo for fermentation to begin and to continue with more or less 
vigor. The heat generated in this process is gradually transmitted to 
the surrounding portions, starting and increasing fermentation, which 
