| 1 pint of water weighs a pound and a quarter. |
| 1 gal. of water = .1605 cu. ft. = 10 lb. of water at 62° F. |
| 1 knot = 6080 ft. = 1.15 statute miles. |
| 1 lb. (avoirdupois) = 7,000 grains = 453.6 grammes. |
| 1 lb. (Troy) = 5,760 grains. |
| 1 English h. p. = 33,000 ft. lbs. of work done per min. = 746 watts. |
| 1 French h. p. or force de cheval = 4,500 kilogram metres per min. = .9863 English h. p. |
| 1 English h. p. = 1.01385 French force de cheval. |
| 1 board of trade electrical unit = 1,000 watts per hour. |
| Volts X amperes = watts. |
| The pressure of one atmosphere = 14.7 lbs. per sq. in. = 2,116 lbs. per sq. ft. = a column of mercury 760 m/m high. |
| A column of water 2.3 ft. high corresponds to a pressure of 1 lb. per sq. in. |
| Cubic inches of cast iron X 0.26 = lbs. avoirdupois. |
| Cubic inches of wrought iron X 0.28 = lbs. avoirdupois. |
| Thickness of wrought iron plate in inches X 40 = lbs. per sq. ft. |
| Sectional area of wrought iron in inches X 3.34 = lbs. per lineal ft. |
| Dia. of wrought iron in inches squared X 2.64 = lbs. per lineal ft. |
Circum. of a circle = dia. X 3.1416
| Area of triangle = base X half the perpendicular height. |
| Area of circle = dia.2 X 0.7854. |
| Circum. of circle = dia. X 3.14159. |
| Circum. of circle X .31831 = the dia. |
| Dia. of circle X .8862 = the side of an equal square. |
| Side of a square X 1.12837 = the dia. of equal circle. |
| Square root of an area X 1.12837 = the dia. of equal circle. |
| Surface of cylinder = area of both ends + length X circum. |
| Surface of cone = area of base + 1/2 (slant height X circum. of base). |
| Surface of sphere = dia. squared X 3.14159. |
| Solidity of sphere = dia. cubed X .5236. |
| Solidity of cylinder = area of one end X length. |
