U.S. BUREAU OF STANDARDS TABLE OF METRIC EQUIVALENTS
Meter = 39.37 inches.
Legal Equivalent Adopted by Act of Congress July 28, 1866.
Length.
| Centimeter | = 0.3937 inch |
| Meter | = 3.28 feet |
| Meter | = 1.094 yards |
| Kilometer | = 0.621 statute mile |
| Kilometer | = 0.5396 nautical mile |
| Inch | = 2.540 centimeters |
| Foot | = 0.305 meter |
| Yard | = 0.914 meter |
| Statute mile | = 1.61 kilometers |
| Nautical mile | = 1.853 kilometers |
Area.
| Sq. centimeter | = 0.155 sq. inch |
| Sq. meter | = 10.76 sq. feet |
| Sq. meter | = 1.196 sq. yards |
| Hectare | = 2.47 acres |
| Sq. kilometer | = 0.386 sq. mile |
| Sq. inch | = 6.45 sq. centimeters |
| Sq. foot | = 0.0929 sq. meter |
| Sq. yard | = 0.836 sq. meter |
| Acre | = 0.405 hectare |
| Sq. mile | = 2.59 sq. kilometers |
Weight.
| Gram | = 15.43 grains |
| Gram | = 0.772 U. S. apoth. scruple |
| Gram | = 0.2572 U. S. apoth. dram |
| Gram | = 0.0353 avoir. ounce |
| Gram | = 0.03215 troy ounce |
| Kilogram | = 2.205 avoir. pounds |
| Kilogram | = 2.679 troy pounds |
| Metric ton | = 0.984 gross or long ton |
| Metric ton | = 1.102 short or net tons |
| Grain | = 0.064 gram |
| U. S. apoth. scruple | = 1.296 grams |
| U. S. apoth. dram | = 3.89 grams |
| Avoir. ounce | = 28.35 grams |
| Troy ounce | = 31.10 grams |
| Avoir. pound | = 0.4536 kilogram |
| Troy pound | = 0.373 kilogram |
| Gross or long ton | = 1.016 metric tons |
| Short or net ton | = 0.907 metric ton |
Volume.
| Cu. centimeter | = 0.0610 cu. inch |
| Cu. meter | = 35.3 cu. feet |
| Cu. meter | = 1.308 cu. yards |
| Cu. inch | = 16.39 cu. centimeters |
| Cu. foot | = 0.283 cu. meter |
| Cu. yard | = 0.765 cu. meter |
Capacity.
| Millimeter | = 0.0338 U. S. liq. ounce |
| Millimeter | = 0.2705 U. S. apoth. dram |
| Liter | = 1.057 U. S. liq. quarts |
| Liter | = 0.2642 U. S. liq. gallon |
| Liter | = 0.908 U. S. dry quart |
| Dekaliter | = 1.135 U. S. pecks |
| Hectoliter | = 2.838 U. S. bushels |
| U. S. liq. ounce | = 29.57 millimeters |
| U. S. apoth. dram | = 3.70 millimeters |
| U. S. liq. quarts | = 0.946 liter |
| U. S. dry quarts | = 1.101 liters |
| U. S. liq. gallon | = 3.785 liters |
| U. S. peck | = 0.881 dekaliter |
| U. S. bushel | = 0.3524 hectoliter |
AVOIRDUPOIS WEIGHT.
| 1 pound | = | 16 ounces | = 256 | drams |
| 1 ounce | = 16 | " |
TROY (APOTHECARIES') WEIGHT (U. S.)
| 1 pound | = | 12 ounces | = 96 drams | = 288 scruples | = 5,760 grains |
| 1 ounce | = 8 drams | = 24 scruples | = 480 grains | ||
| 1 dram | = 3 scruples | = 60 grains | |||
| 1 scruple | = 20 grains |
WINE (APOTHECARIES) LIQUID MEASURE (U. S.)
| 1 gallon | = 8 pints | = 128 fl. ozs. | = 1,024 fl. drams | = 61,440 minims |
| 1 pint | = 16 fl. ozs. | = 128 fl. drams | = 7,689 minims | |
| 1 fl. oz. | = 8 fl. drams | = 480 minims | ||
| 1 fl. dram | = 60 minims |
To find diameter of a circle multiply circumference by .31831.
To find circumference of a circle, multiply diameter by 3.1416.
To find area of a circle, multiply square of diameter by .7854.
To find surface of a ball, multiply square of diameter by 3.1416.
To find side of an equal square, multiply diameter by .8862.
To find cubic inches in a ball, multiply cube of diameter by .5236.
Doubling the diameter of a pipe, increases its capacity four times.
One cubic foot of anthracite coal weighs about 53 lbs.
One cubic foot of bituminous coal weighs from 47 to 50 pounds.
A gallon of water (U. S. standard) weighs 8-1/3 pounds and contains 231 cubic inches.
A cubic foot of water contains 7-1/2 gallons, 1728 cubic inches and weighs 62-1/2 pounds.
To find the number of pounds of water a cylindrical tank contains, square the diameter, multiply by .785 and then by the height in feet. This gives the number of cubic feet which multiplied by 62-1/2 gives the capacity in pounds of water. Divide by 7-1/2 and this gives the capacity in gallons.
A horse-power is equivalent to raising 33,000 pounds 1 foot per minute, or 550 pounds 1 foot per second.
The friction of water in pipes is as the square of velocity. The capacity of pipes is as the square of their diameters; thus, doubling the diameter of a pipe increases its capacity four times.
To find the diameter of a pump cylinder to move a given quantity of water per minute (100 feet of piston being the standard of speed), divide the number of gallons by 4, then extract the square root, and the product will be the diameter in inches of the pump cylinder.
To find the horse-power necessary to elevate water to a given height, multiply the weight of the water elevated per minute in pounds by the height in feet, and divide the product by 33,000 (an allowance should be added for water friction, and a further allowance for loss in steam cylinder, say from 20 to 30 per cent).
To compute the capacity of pumping engines, multiply the area of water piston, in inches, by the distance it travels, in inches, in a given time. Deduct 3 per cent for slip and rod displacement. The product divided by 231 gives the number of gallons in time named.
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.
To find the area of a required pipe, the volume and velocity of water being given, multiply the number of cubic feet of water by 144 and divide the product by the velocity in feet per minute. The area being found, the diameter can be learned by using any table giving the "area of circles" and finding the nearest area, opposite to which will be found the diameter to correspond.