Εικόνες σελίδας
PDF
Ηλεκτρ. έκδοση

WEIGHTS AND MEASURES.

3

AVOIRDU POIS WEIGHT.

......cwt.

437.5 grains (gr.)

1 ounce

oz. 16 ounces

1 pound

.lb. 100 pounds

1 hundredweight 20 cwt., or 2,000 lb..

= 1 ton...

T. 1 T. = 20 cwt. =

2,000 lb.

32,000 oz. = 14,000,000 gr. The avoirdupois pound contains 7,000 grains.

LONG TON TABLE.

16 ounces 112 pounds. 20 cwt., or 2,240 lb.

= 1 pound
= 1 hundredweight
= 1 ton

Ib. ......cwt.

T.

TROY WEIGHT.

24 grains (gr.)

= 1 pennyweight 20 pennyweights

= 1 ounce 12 ounces...

= 1 pound 1 lb. = 12 oz. = 240 pwt.

5,760 gr.

-pwt. ....02.

lb.

DRY MEASURE.

qt.

2 pints (pt.)

= 1 quart 8 quarts

1 peck

pk. 4 pecks.

1 bushel

bu. 1 bu. 4 pk. 32 qt.= 64 pt. The U. S. struck bushel contains 2,150.42 cu. in. = 1.2444 cu. ft. By law, its dimensions are those of a cylinder 181 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 i of a struck bushel.

For approximations, the bushel may be taken at 11 cu. ft.; or a cubic foot may be considered of a bushel.

The British bushel contains 2,218.19 cu. in. 1.2837 cu. ft. = 1.032 U. S. bushels.

.pt.

LIQUID MEASURE. 4 gills (gi.)

1 pint 2 pints

= 1 quart

qt. 4 quarts

= 1 gallon

gal. 31$ gallons.

= 1 barrel

bbl. 2 barrels, or 63 gallons = 1 hogshead

.hhd. 1 hhd. = 2 2 bbl. = 63 gal. = 252 qt.

2,016 gi. The U. S. gallon contains 231 cu. in. = .134 cu. ft., nearly; or 1 cu. ft. contains 7.481 gal. The following cylinders contain the given measures very closely:

504 pt.

Gill
Pint
Quart

Diam.
13 in.
3} in.
31 in.

Height.

3 in, 3 in, 6 in.

Diam.
Gallon 7 in.

8 gallons 14 in.
10 gallons 14 in.

Height.

6 in. 12 in. 15 in.

When water is at its maximum density, 1 cu. ft. weighs 62.425 lb. and 1 gallon weighs 8.345 lb.

For approximations, 1 cu. ft. of water is considered equal to 7} gal., and 1 gal. as weighing 81 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 British to U. S. liquid gallons, multiply by 1.2. Conversely, to convert U. S. into British liquid gallons, divide by 1.2; or, increase the number of gallons

MISCELLANEOUS TABLE.

12 articles 1 dozen. 20 quires 1 ream.
12 dozen
1 gross.

1 league 3 miles. 12 gross 1 great gross.

1 fathom 6 feet. 2 articles 1 pair.

1 hand

4 inches. 20 articles 1 score.

1 palm 3 inches. 24 sheets 1 quire.

1 span

9 inches. 1 sea mile (U. 8.) = 6,080 ft. = 14 statute miles (roughly). 1 meter 3 feet 33 inches (nearly).

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 (do), and milli (robo). 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 LENGTH. 10 millimeters (mm.)

1 centimeter 10 centimeters

1 decimeter 10 decimeters

=1 meter 10 meters

1 decameter 10 decameters

1 hectometer 10 hectometers.

1 kilometer

cm. ..dm.

m. Dm. Hm, Km.

MEASURES OF SURFACE (NOT LAND). 100 square millimeters (mm.) = 1 square centimeter ......cm?. 100 square centimeters

= 1 square decimeter ...... dm?. 100 square decimeters

1 square meter

..m.

MEASURES OF VOLUME. 1,000 cubic millimeters (mm3.) =1 cubic centimeter....... cm3 1,000 cubic centimeters =1 cubic decimeter dm. 1,000 cubic decimeters.

1 cubic meter

.m3

MEASURES OF CAPACITY. 10 milliliters (ml.)

= 1 centiliter..

...cl. 10 centiliters

= 1 deciliter

dl. 10 deciliters

1 liter

.... 10 liters

1 decaliter 10 decaliters.

= 1 hectoliters 10 hectoliters

1 kiloliters

.KI. NOTE.-The liter is equal to the volume that is occupied by 1 cubic decimeter.

DI. .HI.

MEASURES OF WEIGHT.

1 gram

10 milligrams (mg.)

= 1 centigram

cg. 10 centigrams

=1 decigram

dg, 10 decigrams 10 grams

1 decagram.

Dg. 10 decagrams

1 hectogram

.Hg. 10 hectograms

1 kilogram

.Kg. 1,000 kilograms

1 ton

T. 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.

.4300

TEMPERING OF STEEL. The following colors may be made use of in tempering steel-cutting tools:

Corresponding

Temperature Ě. Lancets

Pale yellow Razors

Straw yellow

4500 All kinds of wood-cutting Darker straw yellow tools.

4700 Screw taps

Yellow

4900 Chipping chisels, hatchets,

Brown yellow..

-5000 and saws

Brown (slightly tinged
All kinds of percussive tools

purple)
Light purple

5300

Clear black Springs

.5700 Dark blue..

6000

.5200

CONVERSION TABLES. By means of the tables on pages 8 and 9, metric measures can be converted into English, and vice versa, by simple addition. All the figures of the values given are not required, four or five digits being all that are commonly used; it is only in very exact calculations that all the digits are necessary. Using table, proceed as follows: 1,828.8 Change 6,471.8 feet into meters. Any number, as

121.92 6,471.8, may be regarded as 6,000 + 400 + 70 +1

21.336 +.8; also, 6,000 1,000 X 6; 400 100 X 4, etc.

.3048 Hence, looking in the left-hand column of the

.2438 upper table, page 8, for figure 6 (the first figure of

1,972.6046 the given number), we find opposite it in the third column, which is headed “Feet to Meters,” the number 1.8287838. Now, using but five digits and increasing the fifth digit by 1 (since the next is greater than 5), we get 1.8288. In other words, 6 feet = 1.8288 meters; hence, 6,000 feet 1,000 x 1.8288 = 1,828.8, simply moving the decimal point three places to the right. Likewise, 400 feet 121.92 meters; 70 feet = 21.336 meters; 1 foot =.3048 meter, and .8 foot = .2438 meter. Adding as shown above, we get 1,972.6046 meters.

Again, convert 19.635 kilos into pounds. The 22.046 work should be perfectly clear from the explana

19.8416 tion given above. The result is 43.2875 pounds.

1.3228 The only difficulty in applying these tables lies

.0661 in locating the decimal point; it may always be

.0110 found thus: If the figure considered lies to the left

43.2875 of the decimal point, count each figure in order, beginning with units (but calling unit's place zero), until the desired figure is reached, then move the decimal point to the right as many places as the figure being considered is to the left of the unit figure. Thus, in the first case above, 6 lies three places to the left of 1, which is in unit's place; hence, the decimal point is moved three places to the right. By exchanging the words “right" and "left," the statement will also apply to decimals. Thus, in the second case above, the 5 lies three places to the right of unit's place; hence, the decimal point in the number taken from the table is moved three places to the left.

« ΠροηγούμενηΣυνέχεια »