— 25 — 



air, was used as a measure of tfiose coustitueuts. The amount of 



carbonic acid obtained from three gms. of the different substances 



was as follows : 



At ioo° At no" 



Hay, - - .0156 .0213 



Bran, - - - .0032 .0069 



Cottonseed Meal, .0026 .0042 



The hay loses nuich more by volatilization and oxidation than 

 the bran or cottonseed meal. 



In another experiment, indicating loss by oxidation alone, the 

 current of air was passed through the sulphuric acid and potash 

 bulb without the inlerposition of the copper oxide. Coloration in 

 the sulphuric acid showed the volatile constituents to have been 

 absorbed there ; the yield of carbonic acid was as follows : 



100 cc. no cc. 



Hay, - - .0069 .0125 



Bran, - - - .0020 .0030 



Cottonseed Meal, .0008 .0013 



The hay contains a larger percentage of easily oxidizable con- 

 stituents, with volatile oxidation products than the other two. 



It is evident from these results that in the determination of 

 moisture in fodder there is a decided choice as to methods of treat- 

 ment. Drying by heat with exposure to air is plainly inadmissi- 

 ble, as it involves more or less of substance not moisture, which is 

 even evident to the senses if done in an open dish at 110°. Dry- 

 ing in vacuum over sulphuric acid may be free from any such ob- 

 jection, but requires too much time. Drying in hydrogen at 110° 

 gave such a large increase in loss of weight over the loss at 100° 

 as to arouse suspicion, which was supported by the following re- 

 sults : when this hydrogen was carried from the substance 

 through potash, the increase in weight of the potash bulb after 

 three hours treatment at 100° was less than one mgm. ; but it was 

 from 3 to 20 mgms. with a heat of 1 10°, on another portion of the 

 substance. The hydrogen used may possibly have contained a 

 little oxygen, being made in an ordinary generator, from chemi- 

 cally pure zinc and sulphuric acid, and this might have affected 

 the result somewhat, although slightly. 



Drying at 100° in a current of hydrogen appears, therefore, all 

 things considered, to offer the least objection, and the nearest ap- 

 proach to a correct determination of the hygroscopic moisture in 

 fodder. W. P. CUTTER. 



