ON THE DETERMINATION OF HYGROSCOP- 

 IC WATER IN AIR-DRIED FODDERS. 



The determination of moisture is one of the most important 

 operations in fodder anal3^sis, but as j-et Httle attention has been 

 given to fixing a standard method, based on the results of actual 

 experiments. The amount of dry matter, which serves as a basis 

 for the calculation of the amount of ether-extract, nitrogen, ash, 

 crude fibre, and nitrogen-free extract being directly dependent on 

 the amount of moisture, any inaccuracy in this determination af- 

 fects the amount of the several other constituents found. 



Dr. Jenkins of the Connecticut Experiment Station, in his report 

 to the Committee on Cattle Foods of the Association of Official 

 Agricultural Chemists, published in Bulletin No. 19, Division of 

 Chemistr}^ Department of Agriculture, gave results obtained (i) 

 by drying at 100° in an air bath ; (2) by drying in a current of 

 hydrogen at the same temperature ; and (3) by drying in hydrogen 

 at iio°-ii5°. 



He shows that in three samples of fodder the amount of moist- 

 ure found is larger when the current of hydrogen is employed — 

 also that a temperature of iio°-i 15° causes a greater loss than 

 takes place at 100°. In a similar report, as yet unpublished, he 

 obtains somewhat similar results. 



The following experiments were undertaken to throw some 

 further light on this important matter. 



Three samples of fodder, viz. : hay, wheat bran, and cotton-seed 

 meal, were pulverized as for a complete analysis. Ten different 

 methods of drying were tested, described briefly as follows : 



A. — Drying in watch-glasses in a boiling water bath, tempera- 

 ture quite constant viz., 97°. 



B. — Drying in watch-glasses in an air bath. The temperature 

 did not vary one degree either way from 100°. 



C. — Similar to B, the temperature, however, being raised to 

 iio°-ii5°. 



D. — The substance was placed in a tube through which a cur- 

 rent of dry air was passed, the tube being heated in the water bath 

 at 97°. 



E. — The substance was treated, as in D, with the temperature 

 at 100° 



