107 



FOR REFERENCE. 



Diameter multiplied by 3.1416 equals circumference. 



Circumference multiplied by .3183 equals diameter. 



Radius multiplied by 6.2831 equals circumference. 



Square of the diameter multiplied by .7854 equals area. 



Diameter multiplied by .8862 equals side of equal square. 



Area of a rectangle equals length multiplied by breadth. 



Doubling the diameter of a circle increases its area 

 four times. 



Side of a square multiplied by 1.128 equals diameter of 

 circle of equal area. 



Surface of a sphere equals square of diameter multiplied 

 by 3.1416. 



Area of a triangle equals ba*e multiplied by one-half 

 the altitude. 



Area of a sector of a circle equals one-half the length 

 of the arc multiplied by the radius of the circle. 



1 cu. ft. of water weighs 62 1-3 Ib. and contains 7ft gals. 



1 gal. of water (U. S. Standard) weighs 8 1-3 Ib. 



To find the capacity (U. S. gallons) of cylindrical tanks, 

 square the diameter expressed in inches, multiply by the 

 length and by .0034. 



The pressure of still water in Ib. per sq. in. against the 

 ides of any pipe, channel or vessel of any shape whatever 

 la due solely to the "head" or height of the level surface 

 of the water above the point nt which the pressure la 

 considered, and is equal to .43302 Ib. per sq. in. or 62.355 

 Ib. per sq. ft. for every foot of head. 



STANDARD SPECIFICATIONS FOR CEMENT. 



General Conditions. 



1. All cement shall be inspected. 



I. Cement may be inspected either at the place of 

 manufacture or on the worK. 

 3. In order to allow ample time for inspecting and test- 



