MASONRY. 



A perch of stone is 24.75 cubic feet ; when built in the 

 wall, 22 cubic feet make 1 perch, 2| cubic feet being 

 allowed for the mortar and filling. 



Three pecks of lime and four bushels of sand to a perch 

 of wall. 



To find the number of perches of stone in walls. 



RULE. Multiply the length in feet by the height in feet, 

 and that by the thickness in feet, and divide the product by 

 22, and the quotient will be the number of perches of stone 

 in the wall. 



