The International Metric System Of Weights And Measures

DEPARTMENT OF COMMERCE AND LABORBXiREAU OF STANDARDSS.W. STRATTON,DirectorTHE INTERNATIONALMETRIC SYSTEMWEIGHTS AND MEASURESWASHINGTONGOVERNMENT PRlNTiNG OFFICK1906

DEPARTMENT OF COMMERCE AND LABORBUREAU or STANDARDSS.W. STRATTON,DirectorTHE INTERNATIONALMETRIC SYSTEMOPWEIGHTS AND MEASURESWASHINGTONGOVERNMENT PRINTING OFFICE1906

THE INTERNATIONAL METRIC SYSTEM OF WEIGHTSAND MEASURES.INTRODUCTION.Thefollowing was prepared to answer some of the more simplequestions addressed to the Bureau of Standards in regard to themetric system of weights and measures andits use.The essential features of the system were embodied in a reportmade to the French National Assembly by the Academy of Sciencesin 1 791.A number of other nations were invited to cooperate withFrance in establishing the new system, and Holland, Denmark,Switzerland, Spain, and several minor States were represented onan international commission which met in Paris in 1799 to acceptthe metric standards constructed under the direction of the FrenchInstitute.Although the metric system very soon attracted the favorableit was not until forty years later that itsuse became general in France.Since 1840, however, its use hasattention of other nations,rapidly spread until at the present timeisiteither obligatory orpermissive in every civilized country in the world.made" lawful throughout theUnited States"byItsuse wasact of Congress insame time provision v/as made to supply everyUnion with a set of metric weights and measures.No organized effort had been made up to this time to supply the1866, and at theState in thedifferent countries with authentic copies of the metric prototypeswhich were preservedthedemandin the archives of France.for accurate standardswhoseIn order to meetrelation to one anotherwould be known with the highest precision, metric conventionswere held in Paris in 1870 and 1872, which were attended by official delegates from about thirty countries.At these conferencescommittees were appointed to investigate the best form and material3

BUREAU OF STANDARDS.4newIn 1875 a treaty was signed forpermanentorganization of an International Bureau of Weights and Measuresfor theParisproposedby seventeenstandards.of the principal nations of the world, theunder the direction of an International Committee. The mostimportant work of the International Committee was to provide forthe construction of a sufficient number of platinum-iridium metersand kilograms to meet the demand of the interested nations. Thecomparison of all these standards with one another and with theoriginal meter and kilogram was made at the International Bureauwhich had been established near Paris on neutral territory ceded tothe International Committee by the French Government.This work was completed in 1889, and after selecting a certainmeter and a certain kilogram as the international prototypes, theothers were distributed by lot to the different countries.The international meter and kilogram have values identical with the originalmeter and kilogram, are preserved in a special underground vaultat the International Bureau, and are accessible only to the International Committee.The United States secured two meters andtwo kilograms, which are now preserved at the Bureau of Standardsat Washington and serve as the fundamental standards of lengthand mass of the United States. It is the plan of the InternationalCommittee to intercompare all the national meters and kilogramswith the international prototypes at regular intervals or wheneverconsidered necessary.At the present time the International Bureau of Weights andMeasures is supported jointly by the following countries: TheUnited States, Great Britain, Germany, Russia, France, AustriaHungary, Belgium, Argentine Confederation, Spain, Italy, Mexico,Peru, Portugal, Roumania, Servia, Sweden, Norway, Switzerland,Venezuela, Japan, and Denmark.The advantages claimed for the metric system are:(1) The decimal relation between the units.(2) The extremely simple relation of the units of length, areajvolume, and weight to one another.(3) The uniform and self-defining names of units."Thein 1799.original meterand kilogram "of the Archives" were adoptedas standard

INTERNATIONAL METRIC SYSTEM.5SYNOPSIS OF THE SYSTEM.The fundamental unit ofFrom thisunit of length.the metric systemweight (gram) were derived.divisions or multiplesrelated;e.g.,forallofistheMETER—thethe units of capacity (liter) and ofAll other units are the decimal sub-these.practicalThese three units are simplypurposes one cubicdecimeterequals one LITER and one LITER of water weighs one kilogram.The metricformed by combining the words "METER,""gram," and "liter" with the six numerical prefixes, as in thetables arefollowing Uo- one thousandthone hundredthoneunits1.001lOOO"meter" for length,1.01lOO1tenth.1lOone" gram " for weight or1lOtenone hundivdone thousandlOO1lOOOImass.10100"liter" for capacity.1000UNITS OF LENGTH.milli-metercenti-meterdeci-meter METER"deka-meterhecto-meterkilo-meter.001 meter,.01.1.1- 101001,000Where miles are used in England and the United States formeasuring distances, the kilometer (i,ooo meters) is used in metriccountries.The kilometer is about 5 furlongs. There are about1,600 meters in a statute mile, 20 meters in a chain, and 5 metersin a rod.a One meter equals 39.37 inches exactly.

BUREAU OF STANDARDS.6The meteris used, forstruction, building,used.TheThe meterdry goods, merchandise, engineering con-and other purposes where the yard and foot areisabout a tenth longer than the yard.centimeter and millimeter are used instead of the inch anditsmachine construction and similar work. The centimeter, as its name shows, is the hundredth of a meter.It is usedin cabinet work, in expressing sizes of paper, books, and many caseswhere the inch is used. The centimeter is about two-fifths of aninch and the millimeter about one twenty-fifth of an inch. Themillimeter is divided for finer work into tenths, hundredths, andfractions inthousandths.iiiijiiiiiiiijiiti21Illlllllliiii iiii43mi i iFig. I Mil iiilLilliiiiiiiiiOiiii iiiimii iiii iiii liComparison Scale: 10 Centimeters and 4 Inches.(ActualSize.)a number of distances in millimeters, meters, and kilometers areThey are added as dollars,to be added, reduction is unnecessary.dimes, and cents are now added.For example, " 1,050.25 meters "Ifnot read " i kilometer, 5 dekameters, 2 decimeters, and 5 centimeters," but " one thousand and fifty meters, twenty-five centimeters," just as " 1,050.25 " is read "pne thousand and fifty dollars,istwenty-five cents."AREA.Theformed by squaring the length measures,For land measure 10 meters square isas in our common system.The side of one are iscalled an "are" (meaning "area").HECTARE is 100 meters square, and, as its nameabout 2,2) fi An acre is about 0.4acres.indicates, is 100 ares, or abouttable of areasis

INTERNATIONAL METRIC SYSTEM.7standard United States quarter section contains almostsquare kilo7neter contains 100 hectares.exactly 64 hectares.Theof surface the square meter is used.measuresFor smallerForyard.squarethethanlargersquare meter is about 20 per centsquareinchstill smaller surfaces the square centimeter is used.hectare.AAAcontains about6 square centimeters.VOLUME.cubic measures are the cubes of the linear units. The cubic(sometimes called the stere., meaning "solid") is the unit ofTheONE CUBICDECIMETERONE LITERUNIT OF CAPACITYONE KILOGRAMOF WATERi.Fig. 2.Cubic Decimeter.(ActualSize.)

BUREAU OF STANDARDS.8volume.toAcubic meter of water weighs a metric tonI kiloliter.andisThecubic meterisabout 30 per cent larger.andisequalused in place of the cubic yardThisused for "cuts andisfills"in grading land, measuring timber, expressing contents of tanks andreservoirs, flow of rivers,dimensions of stone, tonnage of ships, andother places where the cubic yard and foot are used.part of the cubic meter (i cubic decimeter)iscalledThe thousandththe WTER. (Seetable of capacity units.)For very small volumes the cubic centimeter (cc or cm ) is used.This volume of water weighs augram, which is the unit of weight orThere are about 16 cubic centimeters in a cubic inch. Themass.cubic centimeteristhe unit of volume used by chemists as well asin pharmacy, medicine, surgery,thousand cubic centimetersmakeand other technical work.Onei liter.UNITS OF CAPACITY. deci-liter LITER'' deka-liter hecto-liter kilo-liter .001 litermilli-litercenti-literThe.01 .1«"""1101001,000hectoliter (100 liters) serves the""same purposesStates bushel (2,150.42 cubic inches), andas the Unitedequal to about 3 bushels,The liter is used for measisA peck is about 9 liters.urements commonly given in the gallon the liquid and dry quarts a liter being 5 per cent larger than our liquid quart and 10 per centsmaller than the dry quart.A liter of water weighs exactly akilogram i. e., 1,000 grams. A thousand liters of water weigh Ior a barrel.metric ton.UNITS OF WEIGHT (OR MASS). centi-gramdeci-gram GRAM deka-gram hecto-gram ,000"10equals 1.05668 liquid quarts or 0.9081 dry quarts.J'One kilogram equals 2.204622 avoirdupois pounds.

LITERPig. 3COMPARISON OFTHE DRY QUART, UTEW.LIQUID QUART. (ACTUAL SIZE.)

lOBUREAU OF STANDARDS.Measurements commonly expressed in gross tons or short tons areThe metric ton comesbetween our long and short tons and serves the purpose of both.stated in metric tons (i,ooo kilograms).FiQ.4, RELATrvE Size of2-Pound and 1-Kiloqram (Brass) Weights. (ActualThe kilogram and"half kilo" serve for everyday trade, the latterThe kilogrambeing lo per cent larger than the pound.imately 2.2 pounds.The gram anditsapprox-multiples and divisions areFig. 6.Relative Size of Avoirdupois Ounce, 30-Gram,AND Troy Ounce ( Brass) Weights. (Actual Size. )Fig. 5.isSize,)Relative Size ofGram and Scruple(Brass) Weights.(ActualSize.)used for the same purposes as ounces, penn5 weights, drams, scruples,and grains. For foreign postage, 30 grams is the legal equivalent ofthe avoirdupois ounce.

STATUS OF THE INTERNATIONAL METRIC SYSTEMTHE UNITED STATES.IN"The Congressof weights***shall have power tofix the standardand measures." (Constitution of the United States.)THE METRIC SYSTEM LEGALIZED.be lawful throughout the United States of America toof the metric system."(RevisedStatutes of the United States, sec. 3569, 1866.)" It shallemploy the weights and measuresTHE METRIC STANDARDS ADOPTED AS FUNDAMENTAL." The office of weights and measures***in the futureregard the international prototype meter and kilogram as fundamental standards, in accordance with the act of July 28, 1866."(Order approved by the Secretar} of the Treasury, April 5, 1893.)FOREIGN POSTAL RATES BASED ON METRIC WEIGHTS." The Postmaster-General shall furnish to the post-offices exchanging mails with foreign countries, and to such other offices as he maydeem expedient, postal balances denominated in grams of the metricsystem, fifteen grams of which shall be the equivalent for postalpurposes, of one-half ounce avoirdupois, and so on in progression."(Revised Statutes of the United States, sec. 3880.)METRIC WEIGHTS USED IN THE COINAGE."The weight ofthe half-dollar shall be twelve grams and one-halfgram; the quarter-dollar and the dime shall be, respectively,one-half and one-fifth of the weight of said half-dollar."(RevisedStatutes of the United States, sec. 3513.)of aCONGRESS PROVIDES METRIC STANDARDS FOR THE STATES OF THEUNION. Be it resolved by the Senate and House of Representatives of theUnited States ofAmerica in Congress assembled That the Secretaryof the Treasury be, and he is hereby, authorized and directed to furnishto each State, to be delivered to the governor thereof, one set of theII