Pocketbook of Useful Formulæ and Memoranda
for Civil and Mechanical Engineers

96 moleswobth's pocket-book Moetar, Cement, &c. Mortar.—1 of lime to 2 to 3 of sharp river sand. Or 1 of lime to 2 sand and 1 blacksmith’s ashes, or coarsely-ground coke. Coabse Mortab.—1 of lime to 4 of coarse gravelly sand. Concrete.—1 of lime to 4 of gravel and 2 of sand. Hydraulic Mortar.—1 of blue lias lime to 2f of burnt clay, ground together. Or 1 of blue lias lime to 6 of sharp sand, 1 of puzzolana and 1 of calcined ironstone. Beton.—1 of hydraulic mortar to 1J of augular stones. Cement.—1 of sand to 1 of cement.—If great tenacity is required, the cement should be used without sand. Waterproof Mastic Cement.—1 of red-lead to 4 of ground lime and 5 of sharp sand mixed with boiled oil. Or 1 of red-lead to 5 of whiting and 10 of sharp eand mixed with boiled oil. Portland Cement is composed of clayey mud and chalk ground together, and afterwards cal- cined at a high temperature—after calcining it is ground to a fine powder,