48 AMERICAN WHEAT AND CORN. 



extended these experiments to all the cereals, and weighing them at in- 

 tervals found that under the conditions which he employed they with- 

 out exception lost about the same amount from summer to winter that 

 they would gain from winter to summer, and that when artificially dried 

 and again exposed to the air, a few minutes would suffice for the absorp- 

 tion of several per cent, of moisture. 



The importance commercially of this capacity for absorbing or losing 

 moisture is of course apparent, and experiments were undertaken before 

 the appearance of Brewer's report for a more thorough investigation of 

 the subject, in reference especially to mill products. 



The materials were exposed in the balance-room of the laboratory of 

 the department properly protected by a screen from exterior influences 

 other than atmospheric. The condition of the atmosphere was noted by 

 means of a psychrometer at the time of weighing. 



The first series consisted of a number of flours from Minnesota, all 

 milled by the roller process from hard spring wheats. Three of the five 

 contained nearly 8 per cent, of water originally, one a little over 9, and 

 one over 13. The first day of exposure was comparatively dry for the 

 climate of Washington, but evidently moist as compared to the locali- 

 ties from which all the flours but one had come, because there was a 

 large gain in the part of three, a small gain by the Pillsbury "A," and 

 a loss by the only one holding originally a large amount of moisture 5 in 

 fact, the result was an approximation to equalization of moisture in all^ 

 as would be expected. If we add the gains and subtract the losses the 

 figures, though not representing actual percentages, would appear for 

 moisture as follows, on the second day : 



The first day's exposure was sufficient, therefore, to equalize the moist- 

 ure in all the flours, and following them through the succeeding weeks 

 ^hey all appear to be susceptible to the changes in condition of moist- 

 ure in about the same degree. 



A specimen of the whole grain exposed beside the flour proved itself 

 .not as susceptible as the finer material, but nevertheless responded to 

 -a certain degree to the daily changes in humidity. A tabulation of the 

 results follows : 



