Oct. 14. 1918 Chemistry of Sweet-Clover Silage 115 



represented the extract from i gm. of silage. This was on the assumption 

 that the average moisture content was 70 per cent. This method of 

 procedure involved a slight error which is without significance in this 

 work. The jar was closed and placed on a shaking machine for two 

 hours, after which the material was strained through a linen cloth into 

 a 500-CC. centrifuge cup, and centrifuged for five minutes at the rate of 

 2,400 revolutions per minute. The average relative force, times gravity, 

 is 1,344 ^-t this speed, according to the statement of the manufacturer. 

 This gave a clear but dark-colored supernatant liquid. In order not to 

 stir up the sediment in the bottom of the cup, it was necessary to allow 

 the centrifuge to come to a stop without using the brake. Because of 

 the presence of some light particles which would not settle to the bottom, 

 it was necessary to filter on folded filters. This filtrate was then used 

 for the following determinations : 



(i) Acidity by titrating to phenolphthalein. 



(2) Acidity by using the hydrogen electrode. 



(3) The nitrogen in amino form, by titrating in the presence of formal- 

 dehyde using thymolphthalein as indicator. 



(4) The nitrogen in amino form by titrating in the presence of for- 

 maldehyde to a certain hydrogen-ion concentration, using the hydrogen 

 electrode. 



(5) Total nitrogen in the water extract. 



(6) Total nitrogen in water extract not precipitated by phosphotungs- 

 tic acid. 



An attempt was made to determine nitrogen in the water extract by 

 Stutzer's method, but the amounts were so small that differences were 

 within the analytical error. 



METHOD OF MAKING THE ALCOHOLIC EXTRACT OF SILAGE 



When each bottle was opened, 100 gms. of the silage were weighed into 

 a quart Mason jar and 250 cc. of 95 per cent alcohol added. The jar was 

 then sealed and allowed to stand till a convenient time for doing the 

 work. This was necessary, as the work on the water extract had to be 

 finished at once, and occupied the available time. On the basis of total 

 moisture in the silage, previously determined, enough carbon-dioxid-free 

 water was added to the jar to make the volume 500 cc. This would make 

 the percentage of the alcohol about 50. After adding this water the jar 

 was sealed, shaken, and allowed to stand for an hour, when the material 

 was strained through linen cloth. From this point the precedure was 

 the same as with the water extract, and the same chemical determina- 

 tions were made. 



