APPENDIX. 



WATER. 



One gallon of water weighs 8^ pounds and contains 231 cubic 

 inches. One cubic foot of water contains 7^ gallons, 1,728 cubic 

 inches, and weighs 62^ pounds. One cubic inch of water evaporated 

 under atmospheric pressure is converted into approximately one 

 cubic foot of steam. The height of a column of fresh water equal 

 to 1 pound pressure per square inch is 2.31 feet. In usual computa- 

 tion this is taken at 2 feet. 



To find the pressure in pounds per square inch of a column of 

 water, multiply the height of the column in feet by 0.434. Approxi- 

 matel}^ every foot elevation is equal to one-half pound pressure per 

 square inch, allowing for friction. 



Pressure of irater for each foot in height. 



Feet in height. 



Pounds 



per 

 square 

 inch. 



Feet in height. 



Pounds 



per 

 square 

 inch. 



Feet in height. 



Pounds 



per 

 square 

 inch. 



1 



0.43 



.86 



2.16 



4:33 



15 



6.49 



8.66 



10. S2 



17.32 



50 



21.65 





20 .. 



70 -. . . 



30 32 



5 .... 



25 



80 



34. 65 



10 



40 



100 



43.31 











To find the velocity in feet per minute necessary to discharge a 

 given volume of water in a given time., multiply the number of cubic 

 feet of water by 144 and divide the product by the area of the pipe 

 in inches. Doubling the diameter of a pipe increases its capacity 

 four times. A miner's inch of water is approximately equal to a sup- 

 ply of 12 gallons a minute. 



Jleasurenient of an open stream by velocity and cross section. — 

 Measure the depth of the water at from 6 to 12 points across the 

 stream at equal distances between. Add all the depths in feet and 

 inches together and divide by the number of measurements. This 

 will give the average depth, which when multiplied by the width will 

 give the area of the cross section. 



The velocity of the stream can be found by laying off 100 feet 

 along the bank and throwing a float into the middle, noting the 

 time taken in passing over 100 feet. Do this a number of times and 

 take the average. Then divide this distance by the time, and it will 

 be the velocity at the surface. As the top of the stream flows faster 



57 



