1179, U. S. Dept. of Agriculture. 
Plate IV. 
Fig. I. — Several Types of Briquets Used in Large-Scale Experi- 
ments on the Volatilization of Phosphoric Acid in an Oil-burning 
Furnace. 
Fig. 2. — Effect of the Oil Flame on Briquetted Charge Before 
Fusion Takes Place. Unburned Briquets on Right, Burned 
Briquets on Left, and Broken Burned Briquets in Center Show- 
ing Unaltered Carbon Within the Mass. 
