The Metric System. The Metric System. (Prepared for the U. S. Government by the Bureau of Standards. Department of Commerce.) UNITS OF WEICHT AND MEASURE. 87 THE fundamental unit of the metric system is the meter, the unit of length. From this the units of capacity (liter) and of weight (gram) were derived. All other units are the decimal subdivisions or multiples of these. These three units are simply related, e. g., for all practical purposes 1 cubic decimeter equals 1 liter and 1 liter of weight weighs 1 kilogram. The metric tables are formed by combining the words "meter," "gram," and "llter" with tife six numerical prefixes, as in the following tables: All lengths, areas, and cubic measures in the following tables are derived from the international meter, the legal equivalent being 1 meter = 39.37 inches (law of July 28, 1866). In 1893 the United States Office of Standard Weights and Measures was authorized to derive the yard from the meter, using for the purpose the relation legalized in 1856, 1 yard = 3600-3937 meter. The customary weights are likewise referred to the kilogram (Executive order approved April 5,-1893). This action fixed the values, inasmuch as the reference standards are as perfect and unalterable as it is possible for human skill to make them at this time. All capacities are based on the equivalent 1 liter equals 1.000027 cubic decimeters. The decimeter is equal to 3.937 inches in accordance with the legal equivalent of the meter given above. The gallon referred to in the tables is the United States gallon of 231 cubic inches. The bushel is the United States bushel of 2.150.42 cubic inches. These units must not be confused with the British units of the same name, which differ from those used in the United States. The British gallon is approximately 20 per cent larger and the British bushel 3 per cent larger than the corresponding units used in this country. The customary weights derived from the international kilogram are based on the value 1 avoirdupois pound = 453.5924277 grams. The value of the troy pound is based upon the relation just mentioned and also the equivalent 5760-7000 avoirdupois pounds equals 1 troy pound. DEFINITIONS OF UNITS. LENGTH. Fundamental Units-A meter (m) is a unit of length equivalent to the distance between the defining lines on the international prototype meter at the International Bureau of Weights and Measures when this standard is at the temperature of melting ice (0° C). A yard (yd.) is a unit of length equivalent to 3600-3937 of a meter. Fundamental Units: 1 liquid pint 1-8 gallon 1-2 liquid quart= 1 gill 1-32 gallon = 1-4 liquid pint = 7,21875 1 fluid ounce 1-128 gallon = 1-16 liquid pint. 1 peck = 1-4 bushel 537.605 cubic inches. = 1 dry quart = 1-32 bushel 1-8 peck = 67.200625 cubic inches. 1 dry pint = 1-64 bushel 1-2 dry quart 33.6003125 cubic inches. 1 barrel (for fruit, vegetables and other dry commodities) = 7056 cubic inches = 105 dry quarts. The barrel capacity was fixed by United States statute, approved March 4, 1915. MASS. A kilogram is a unit of mass equivalent to the mass of the international prototype kilogram at the International Bureau of Weights and Measures. An avoirdupois pound is a unit of mass equivalent to 0.4535924277 kilogram. A gram is a unit of mass equivalent to one-thousandth of the mass of the international prototype kilogram at the International Bureau of Weights and Measures. A troy pound is a unit of mass equivalent to 5760-7000 of that of the avoirdupois pound. Multiples and Submulti ples. 1 metric ton = 1000 kilograms. 1 hectogram = 100 grams = 0.1 kilogram. 1 dekagram = 10 grams = 0.01 kilogram. 1 decigram = 0.1 gram. 1 centigram = 0.01 gram. 1 milligram = 0.001 gram. == 1 avoirdupois ounce = 1-16 avoirdupois pound. 1 gram = 1-700 avoirdupois pound = 10-4375 1 apothecaries' pound = 1 troy pound = 5760-7000 avoirdupois pound. 1 apothecaries' or troy ounce 1-12 troy pound = 480-7000 avoirdupois pound = 480 grains. 1 apothecaries' dram = 1-96 apothecaries' pound = 1-8 apothecaries' ounce = 60 grains. 1 pennyweight = 1-20 troy ounce = 24 grains. 1 apothecaries' scruple = 1-3 apothecaries' dram 20 grains. 1 metric carat 200 milligrams = 0.2 gram. 1 short hundredweight = 100 avoirdupois pounds. 1 long hundredweight = 112 avoirdupois pounds. 1 short ton = 2000 avoirdupois pounds. 1 long ton = 2240 avoirdupois pounds. STANDARDS FOR MEASUREMENT, Units of measurement should be distinguished from standards for measurement, particularly in the case of length and capacity. Units of length are fixed distances, independent of any other consideration, while length standards are affected by the expansion and contraction with changes of temperature of the material of which the standard may be composed. It is therefore necessary to fix upon some temperature at which the distance between the defining lines or end surfaces of the standards shall be equal to the unit. The same is true of standards of capacity, which at some definite temperature contain a given number of units of volume. The temperature at which metric length standards are customarily made correct is 0° C, although 20° C is also used for steel tapes and some other standards intended for use at room or average outdoor temperatures. The temperature at which standards of length of the customary system are made correct is 62° F. For measurements of high precision it is also necessary to specify the manner of support of the standards, whether at certain points only or throughout their entire length, and in the case of tapes it is also necessary to give the tension applied to the tape when in use. In the United States the capacity standards, both metric and customary, are made to hold the specified volumes at 4° C. Standards of capacity are usually made of brass so the capacity at any other temperature may be computed by the use of the coefficient of cubical expansion, usually assumed to be 0.000054 per degree centigrade. In the purchase and sale of liquids a more important consideration than the temperature of the measures is the temperature of the liquid when measured, for the reason that the large coefficient of expansion of many liquids makes the actual mass of a given volume delivered vary considerably with temperature. For this reason, the custom of buying and selling liquids by weight instead of by measure is recommended. It is further recommended that, when liquids are sold by volume, 68° F or 20° C be adopted as the standard temperature of the liquid. While the temperature of a weight does not affect its mass, it is nevertheless important that when two weights are compared in air they both be at the same temperature as the air. If there is a difference between the temperature of the air and the weights, convection currents will be set up and the readings of the balance will be thereby affected. Also, since weights are buoyed up by the surrounding air by amounts dependent upon their volumes, it is desirable that the weights of any set be of the same material. If two weights of the same density balance in air of a certain density they will balance in vacuo or in air of a different density. Brass is the material most widely used for standard weights, although platinum is quite commonly used for weights of 1 gram or less. In the absence of any knowledge as to the actual density of weights, those made of brass are assumed to have a density of S.4 at o° C, while those of platinum are assumed to. have a density of 21.5 at o° C. SPELLING AND ABBREVIATION OF UNITS. The spelling of the names of units adopted by the National Bureau of Standards is that given in the list below. The spelling of the metric units is in accordance with that given in the law of July 28, 1866, legalizing the metric system in the United States. Following the names of each unit in the list below is given the abbreviation which the Bureau has adopted Attention is called to the following principles: 1. The period is omitted after the abbreviations of the metric units, while it is used after those of the customary system. 2. The exponents, "2" and '3," are used to signify area and volume, respectively, in the case of the metric units instead of the longer prefixes "sq." or "cu." In conformity with this principle the abbreviation for cubic centimeter is "cm3," instead of c. c. or c. cm.' The term "cubic centimeter" as used in chemical work is, in fact, a misnomer, since the unit actually used is the "milliliter," which has a slightly larger volume. 3. The use of the same abbreviation for both singular and plural is recommended. This practice is already established n expressing metric units and is in accordance with the spirit and chief purpose of abbreviations. 4 It is also suggested that, unless all the text is printed in capital letters, only small letters be used for abbreviations except in the case of A. for acre, where the use of the capital letter is general. Feet Cubic yards Cubic ¡Cubic meters meters Ft., Yds, Miles, Acres, Qts., Etc., With Metric Equivalents. 89 FEET, YARDS, MILES, ACRES, QTS, ETC,, WITH METRIC EQUIVALENTS. (By S. W. Stratton, Director of the United States Bureau of Standards, Department of Commerce.) Feet Meters Meters 0.30480 3.28083 .60960 6.56167 .91440 9.84250 13.12333 3.82280 4.58736 5.35192 6.11648 6.88104 7.64559 8.41015 9.17471 9.93927 10.70383 11.46839 Acres Hectares Hectares Acres 8 14.8260 18.5325 5.39593 10 4.04687 10 2 22.2390 24.0922 25.9455 27.7987 29.6520 31.5052 33.3585 35.2117 1 4.45156 3 5.26093 5.66562 6.07031 6.47300 6.87968 7.28437 7.68906 8.09375 20 8.49843 8.90312 1.21406 Kilos Kilos 90 Ft., Yds., Miles, Acres, Qts, Etc., With Metric Equivalents-Cont. TABLES OF INTER-RELATION OF UNITS OF MEASUREMENT. UNITS OF LENGTH. 1 in. = 0.126263 links = 0.083333 ft. = 0.027777 | 0.25 chains = 0.003125 yds. = 0.005050 rds. 0.001262 chains = 0.000015 | 5.029210 meters iniles 2.540 cms. =0.025400 meters. 1 yd. = 36 36 ins. ins. 4.54545 links = 3 ft. = 0.181818 rds. = 0.0454545 chains = 0.000568 miles = 91.440 cms. = 0.914401 meters. 1 chain = 792 ins. = 100 links=66 ft. = 22 yds. = 4 rds. 0.0125 miles. 2011.684 cms. 20.11684 meters. = 1 mile 63360 ins. = 8000 links = 5280 ft. = 1760 yds. 320 rds. 80 chains 160934.72 cms. = 1609.= 3472 meters. = 1 cm. = 0.39 ins. = 0.049709 links = 0.03280833 ft. = 0.010936 yds. = 0.001988 rds. = 0.00049709 chains= 0.0000062 miles = 0.01 meters. 1 meter = 39.37 ins. = 4.970960 links = 3.280833 ft. = 1.093611 yds. = 0.198838 rds. = 0.04970960 chains 1 rd. 198 ins. = 25 links 16.5 ft. 5.5 yds. = = = = 0.0006213 miles 100 cms. UNITS OF AREA. = 1 sq. in. = 0.0159423 sq. links = 0.00694444 sq. yds. | 4356 sq. ft. 484 sq. yds. = 16 sq. rds. = 0.1 acres = 0.000025507 sq. rds. 0.000001 sq. chains = 0.00015625 sq. miles = 404687 sq. cms. 404.6873 0.000000159 acres 0.0000000002491 sq. miles = sq. meters = 0.0404687 hectares. 6.4516 cms. = 0.000645 sq. meters = 0.000000064 hectares. = 1 sq. link=62.7264 sq. ins. 0.4356 sq. ft. = 0.0484 sq. yds. = 0.0016 sq. rds. = 0.0001 sq. chains0.00001 acres 0.0000000156 sq. miles = 404.6873 sq. cms. 0.040468 sq. meters = 0.000004046 hectares, 1 sq. ft. 144 sq. ins. = 2.295684 sq. links = 0.1111111 sq. yds. = 0.00367309 sq. rds. = 0.000229 sq. chains= 0.000022956 acres = 0.0000000358701 sq. miles 929.0341 sq. cms. = 0.092903 sq. meters = 0.000009290 hectares. 1 sq. yd. 1296 sq. ins. 20.6612 sq. links 9 sq. = ft.= 0.03305785 sq. rds. = 0.00206612 sq. chains = 0.000206612 acres = 0.000000322831 sq. miles = 8361.307 sq. cms. 0.836130 sq. meters = 0.000083613 hectares. = 1 sq. rd. =39204 sq. ins. = 625 sq. links = 272.25 | sq. ft. - 30.25 sq. yds. = 0.0625 sq. chains = 0.00625 acres = 0.0000097656 sq. miles = 252929.5 sq. cms. =25.29295 sq. meters = 0.002529295 hectares. 1 sq. chain = 627264 sq. ins. 10000 sq. links = UNITS OF 1 cu. in = 0.000578704 cu. ft. = 0.000021-43347 cu. yds. 16.387102 cms. = 0.01638716 cu dms. 0.00001638716 cu. meters. ་ 1 cu. ft. = 1728 cu. ins. ins. = 0.0370370 cu. yds. 28317.016 eu. ems. 28.317016 cu. dms. = 0.028317 016 cu. meters. 1 sq. mlle 4014489600 sq. ins. = 64000000 sq. links 27878400 sq. ft. 3097600 sq. yds. = 102400 sq. rds. 6400 sq. chains 640 acres 2589998470 = = sq. cms. 2589998 sq meters = 258.9998 hectares. 1 sq. cm. = 0.1549997 sq. ins. = 0.00247104 sq. links 0.00107638 sq. ft. = 0.00011959 sq. yds. = 0.000003953 sq. rds. = 0.000000247 sq. chains=0.00000002471 acres = 0.00000000003861 sq. miles = 0.0001 sq. meters 0.00000001 hectares. = = 1 sq. meter = 1549.9969 sq. ins. = 24.7104 sq. links = 10.763087 sq. ft. 1.195985 sq. yds. = 0.0395367 sq. rds.0.002471 sq. chains 0.000247104 acres = 0.0000003861006 sq. miles 1000 sq. cms. = 0.0001 hectares. 1 hectare 15499969 sq. ins. 247104 sq. links = = 1076387 sq. ft. 11959.85 sq. yds. 395367 sq. rds. = 24.7104 sq. chains = 2.47104 acres = 0.003861006 sq. miles = 10000000 sq. cms. 10000 sq. meters. VOLUME. 1 cu. dm. 61.02338 cu. ins. = 0.03531445 cu. ft. = 0.001307943 cu. yds. = 1000 1000 cu. cms. 0.001 = = cu. meters. 1 cu. meter = 61023.38 cu. ins. = 35.31445 cu. ft. = 1.3079428 cu. yds. yds. 1000000 cu. cms. = 1000 cu. dms. UNITS OF CAPACITY-LIQUID MEASURE. 1 minim = 0.01666 A. dr. = 0.00208 fl. oz. = 0.000520 gills 0.000130 liq. pts.0.00006510 liq. qts. = 0.000016 gals. 0.06161 ml. = 0.000061 liters= 0.003759 cu. ins. 1 fl. dr. = 60 minims = 0.125 fl. ozs. = 0.03125 gills = 0.007812 liq, pts. = 0.003906 liq. qts. = 0.000976 gals. = 3.69661 mis, = 0.003596 liters = 0.225586 cu. ins. 1 fl. oz. 480 minims = 8 1. drs. 0.25 gills = 0.0625 liq. pts. = 0.03125 liq. qts. = 0.007812 gals = 29.5729 mls. 0.029572 liters = 1.80469 cu. ins. 1 liq. qt. = 15360 minims = 256 fl. drs. = 32 f. ozs. 8 gills 2 liq. pts. 0.25 gals. 946333 mils. = 0.946333 liters = 57.75 cu. ins. = 1 gal. 61440 minims = 1024 fl. drs. 128 fl. ozs. = 32 gills = 8 liq. pts. = 4 llq. qts. 3785.332 mls. = = 3.785332 liters = 231 cu. ins. = 1 ml. 16.231 minims = 0.27051 fl. drs. = 0.0338147 fl. ozs. = 0.008453 gills = 0.002113 liq. pts. 0.0010567 liq. qts. 0.000264 gals. 0.001 İlters = 0.061025 cu. ins. 1 liter 16231.1 minims 270.518 fl. drs. 33.8147 fl. ozs. = 8.45368 gills. =2.11342 liq. pts. 1.05671 liq, qts. = 0.264178 gals. 1000 mls. 61.0250 cu. ins. = 1 cu. in. = 265.974 minims = 4.43290 fl. drs. = 0.554113 fl. ozs. 0.138528 gills = 0.0346320 liq. pts. 0.0173160 llq. qts. 0.004329 gals. = 16.3867 = = mls. 0.0163867 liters. DRY MEASURE. UNITS OF CAPACITY 1 dry pt. 0.5 dry qts. = 0.0625 pks. = 0.015625 bu. =0.550599 liters = 0.055060 dkl. = 33.6003125 cu. ins. 1 dry qt. = 2 dry pts. 0.125 pks. = 0.03125 bu. = 1.101198 liters = 0.110120 dkl. 67.200625 cu. ins. 1 pk. 16 dry pts. = 8 dry qts. 0.25 bu. 8.80958 = liters 0.880958 dkl. = 537.605 cu. ins. 1.81620 dry pts. = 0.908102 dry qts. = pks. 0.028378 bu. = 0.1 dkl. = 61.0250 1 dkl. 18.1620 dry pts. = 9.08102 dry qts. = 1.13513 pks. 0.28378 bu. 10 liters 610.250 cu. ins. 1 cu. in. 0.0297616 dry pts. = 0.0148808 dry qts. 0.00186010 pks. = 0.000465025 bu. = 0.0163867 liters 0.00163867 dkl. Comparison of Metric and Customary Units, 1 to 9. UNITS OF MASS LESS THAN POUNDS AND KILOGRAMS—Continued. 91 1 apoth, or troy lb. = 576 grs. 288 apoth. scruples =240 dwt.=210.6514 av. drs. 96 apoth. drs, = 13.165714 av. ozs. = 12 apoth, or troy ozs. = 0.8228571 av. lbs. 373241.77 mgs. 373.24177 grams=0.373241 kgs. = = 1 av. Ib. = 7000 grs. = 350 apoth. scruples = 291.6667 dwt. dwt. = 256 av. dra. 116.6667 apoth drs. 16 av. ozs. = 14.583333 apoth. or troy ozs. = 1.215277 apoth. or troy lbs. = 453592.427 mgs. = 453.59242 grams= 0.453592 kgs. 1 mg. = 0.015432 grs. = 0.0007716 apoth. scruples= 0.00064301 dwt. = 0.0005643833 av. drs. = 0.000257 apoth. drs. = 0.000035 av. ozs. = 0.000032 apoth. or troy ozs.0.000.002 apoth. or troy lbs. = 0.000002 av. lbs. = 0.001 grams = 0.000001 kgs. UNITS OF MASS GREATER THAN AVOIRDUPOIS OUNCES. 1 av. oz. =0.0625 av. lbs. = 0.000625 short cwt.= 0.00003125 short tons = 0.00002790179 long tons = 0.02834953 kgs. = 0.00002834953 metric tons. = short cwt.=0.8928571 long tons = 907.18486 kgs. = 0.90718486 metric tons. long_ton 1 long ton = 35840 av. ozs. = 2240 av. lbs. = 22.4 short cwt. = 1.12 short tons = 1016.04704 kgs. 1.01604704 metric tons. |