SQUARE MEASURE.

144 square inches (sq. in.).......

=

1 square foot

sq. ft. sq. yd.

sq. rd.

sq. yd.

3,097,600

1 acre

The acre contains 4,840 sq. yd., or 43,560 sq. ft., and in form of a square is 208.71 ft. on a side.

1 T. 20 cwt. 2,000 lb.

32,000 oz. = 14,000,000 gr.

The avoirdupois pound contains 7,000 grains.

= 1.2444

The U. S. struck bushel contains 2,150.42 cu. in. cu. ft. Its dimensions are, by law, 18 in. in diameter and 8 in. deep. The heaped bushel is equal to 14 struck bushels, the cone being 6 in. high. The dry gallon contains 268.8 cu. in., being bu.

For approximations, the bushel may be taken at 14 cu. ft.; or a cubic foot may be considered of a bushel.

The British bushel contains 2,218.19 cu. in. 1.032 U. S. bushels.

1.2837 cu. ft.

The U. S. gallon contains 231 cu. in. = .134 cu. ft., nearly; or 1 cu. ft. contains 7.480 gal. The following cylinders contain the given measures very closely:

With water at its maximum density (weighing 62.425 lb. per cu. ft.), a gallon of pure water weighs 8.345 lb.

For approximations, 1 cu. ft. of water is considered equal to 7 gal., and 1 gal. as weighing 8 lb.

The British imperial gallon, both liquid and dry, contains 277.274 cu. in. .16046 cu. ft., and is equivalent to the volume of 10 lb. of pure water at 62° F. To reduce U. S. to British liquid gallons, divide by 1.2. Conversely, to convert British into U. S. liquid gallons, multiply by 1.2; or, increase the number of gallons }.

THE METRIC SYSTEM.

The metric system is based on the meter, which, according to the U. S. Coast and Geodetic Survey Report of 1884, is equal to 39.370432 inches. The value commonly used is 39.37 inches, and is authorized by the U. S. government. The meter is defined as one ten-millionth the distance from the pole to the equator, measured on a meridian passing near Paris.

There are three principal units-the meter, the liter (pronounced lee-ter), and the gram, the units of length, capacity, and weight, respectively. Multiples of these units are obtained by prefixing to the names of the principal units the Greek words deca (10), hecto (100), and kilo (1,000); the submultiples, or divisions, are obtained by prefixing the Latin words deci (), centi (1), and milli (oo). These prefixes form the key to the entire system. In the following tables, the abbreviations of the principal units of these submultiples begin with a small letter, while those of the multiples begin with a capital letter; they should always be written as here printed.

MEASURES OF VOLUME.

1,000 cubic millimeters (mm3)= 1 cubic centimeter 1,000 cubic centimeters......... 1 cubic decimeter 1,000 cubic decimeters.......= 1 cubic meter

MEASURES OF CAPACITY.

cm3.

dm3.

m3.

NOTE.-The gram is the weight of 1 cubic centimeter of pure distilled water at a temperature of 39.2 F.; the kilogram is the weight of 1 liter of water; the ton is the weight of 1 cubic meter of water.