32 



BULLETIi!^ lOi, U. S. DEPARTMENT OF AGRICULTURE. 



to tlie fact that tlie short horizontal lines gradually drop below the original 

 base line. Each vertical line which shows above the corresponding horizontal 

 base line on its right should be counted as part of the record. 



A^ 



>=>Z.y*7/'V 



Jkf 



Fig. 3. — Details of Pag(! impact machine for testing cementing value. 



The number of blows required to destroy the specimen is called its cementing 

 value. An average of five determinations is taken. 



