REPORT OF THE CHEMIST. 



101 



The interest of the analyses centers in the presence of so much sugar 

 and soluble albuminoids. The sugar has been calculated to percentage 

 as if it were dextrose. It does not reduce Fehling's solution until in- 

 verted by acids. It is dextro-rotatory, by inversion becoming less so, 

 but not laevo-rotatory. It is uncertain whether it is formed from starch 

 which may be present through the action of some ferment in the germ ; 

 but it seems probable, especially since so much soluble nitrogen is 

 present pointing to diastatic action, and it may be classed somewhere 

 between dextrine and maltose. In fact it has been found that the water 

 extract if left in contact with the residue of the germ would soon be the 

 cause of a peculiar fermentation. This shows the bad effect the pres- 

 ence of this soluble albuminoid would have in flour, causing a fermenta- 

 tion or putrefaction which would injure and discolor it. The oil in the 

 germ is also an additional source of trouble, in that it is readily oxidized 

 under certain circumstances and tends to blacken the flour. 



THE RELATIONS OF THE WHEAT GRAIN AND ITS PRODUCTS TO THE 

 HUMIDITY OF THE AIR. 



In the report of W. H. Brewer on the cereals, in Yol. Ill of the Cen- 

 sus for 1880, he gives the results of certain experiments by Hilgard, of 

 California, showing the changes in weight of wheat when exposed to 

 alternations of dry and moist air. California wheat, being particularly 

 dry as it comes from the hot valleys where it grows, absorbs a large amount 

 of moisture in the seaports or during transportation by sea. Brewer 

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

 intervals, found that under the conditions which he employed they 

 without 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 

 absorption 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 ; 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 : 



