# Popular Science Monthly/Volume 64/March 1904/The Metric System: Shall it Be Compulsory?

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* THE METRIC SYSTEM: SHALL IT BE COMPULSORY?
By Professor W. LE CONTE STEVENS,
WASHINGTON AND LEE UNIVERSITY.
NO tribe of savages has ever been found that did not present some evidence of the existence of individual property among them. By force of character and personal prowess the chief acquires possessions of increasing variety. Where compulsion can not be directly applied resort is had to exchange, and this at once develops the need for measurement of values. Local convenience suggests conventional standards for the measurement of quantity, and custom tends to fix such standards. When a number of tribes have become aggregated into an embryonic nation, the different standards are soon found to need revision. From a group of temporary standards some fall into disuse and the most convenient are retained. The readiest standard of length is some part of the human body, such as the forearm or hand. The cubit is thus one of the most ancient of units. The foot, the pace, the palm, the digit, the inch as the length of the last bone of the thumb, the yard as arm length from mouth to finger tip, all of these are units of unknown antiquity, and accurate enough for the common needs of many who are moderately civilized to-day.
The unit of length is the primary unit to which finally all others are referred. To derive from it units of surface and volume would appear most natural, and it seems but a short step farther to derive a unit of mass from the unit volume of some selected kind of matter, such as water or earth. But it is safe to say that such a process of derivation was unknown until within the last few centuries or even less. For the comparison of masses scales were early developed, and with the advance of civilization linear units derived from human bodies of variable size gave place to metallic standards prepared and kept by some central authority. From the buried city of Pompeii have been taken steelyards carrying inscriptions which showed that they had been 'proved' by comparison with the standards kept in the Temple of Jupiter at Rome.
In England the standard of length during the last eight or nine centuries has been the yard, traditionally derived from the length of the arm of King Henry I. about the year 1101. A rod or bar of this length was kept in London, and copies of it, of various grades of crudeness, received the royal stamp which made them legal measures. One third of this length was called a foot, although about one fifth ​longer than the average masculine foot. Both in England and on the continent legislation relating to standards of measurement was exceedingly lax, and in every important town the local magistrate developed or maintained his own municipal system of weights and measures. A comparison of nomenclature in different languages shows that the foot has been the generally selected unit of length; and the Latin word pondus meaning a weight, has been used with variations, such as pound and pfund, to express the popular unit of weight. With such unlimited local freedom, such imperfect means of communication, and such scanty diffusion of education, it is not remarkable that even so recently as a century ago the number of different units of length and weight, called by similar names, should be so great as almost to defy numeration. Even as late as 1850, in a 'Dictionary of Weights and Measures' at that time known, 5,227 of these were recorded. There were 135 varieties of foot; 60 of the inch; 29 of the pint; 53 of the mile, and 235 of the pound. The names foot and pound, or their equivalents in widely different languages, have been applied to magnitudes, nominally constant but practically variable, during the last 2,000 years. The Olympic foot, in use among the ancient Greeks, was traditionally derived from the foot of Hercules. To eradicate the popular devotion to these standards, variable as they may be, can not be accomplished in a generation. The range of variation among different values of the foot has been from 8.75 inches to 23.22 inches, or over 165 per cent.
Standards of weight and measure are thus the products of the people. The fundamental condition to be fulfilled is that a standard shall be definite and invariable. The function of legislation is not to create standards, but to adopt and protect them. This necessity was appreciated certainly as far back as the time of the Romans, but the recognition of it implies a degree of civilization that was not shared with them by the peoples they had nominally conquered. In England there is no record of such legislation prior to the thirteenth century. By statute of King Henry III., A. D. 1266, the combined standard of money, weight and capacity was defined by the statement that 'an English penny, called a sterling, round and without any clipping, shall weigh thirty-two wheat corns in the midst of the ear ; and twenty pence do make an ounce, and twelve ounces one pound, and eight pounds do make a gallon of wine, and eight gallons of wine do make a London bushel, which is the eighth part of a quarter. ' This pound, thus equal to the weight of 7,680 wheat grains, was known as the sterling or easterling pound, and had long been in use among the nations of eastern Europe. It is supposed to have been brought to England in the time of the Crusades. The troy pound and the avoirdupois pound additionally came into use, their origin and time of introduction being ​unknown. The pound sterling continued to be the legal standard until 1496, when it was superseded by the pound troy.
King Edward II., in 1324, provided by statute that the inch should have the length of 'three barley corns, round and dry, laid end to end.' Of these inches 12 were to make one foot, and 36 of them one yard. The length of a barley corn must have been known to be quite as variable as that of the royal arm. Yard sticks were indeed kept in the royal exchequer, but care in preservation seems to have been quite as unknown as methods of precision in construction.
By the middle of the eighteenth century the influence of such men as Sir Isaac Newton had produced a very perceptible effect on English civilization. The Royal Society of London, chartered in 1662 and including all the scientific leaders of the kingdom, recognized the chaotic condition of English weights and measures; and in 1742 a standard yard was constructed by one of its members, George Graham, who determined the ratio of its length to that of a pendulum beating seconds. This pendulum length he found to be 39.14 inches. It is most unfortunate that this length was not adopted as that of the yard, even if its value was not known with the utmost precision. Had the inch been defined as one fortieth part of this length, and the foot as ten inches, not only would the foot have been made to accord with the actual length of the average masculine foot, but a decimal division of it would have been established. The binary division of the yard would have been maintained, and its value would have been so nearly the same as that of the meter, afterward adopted as an international unit of length, that identification of the British and metric units would have been easy. But the people were not seeking ideals. Graham's yard was constructed for the Royal Society and there is no evidence of its adoption by the government. The official standard until 1824 was a brass rod made in 1570. It had been broken and mended so badly that the joint was described to be 'nearly as loose as that of a pair of tongs.' A copy of Graham's yard was made by Mr. Bird for a parliamentary committee in 1758 and another in 1760, but not adopted until 1824. This was known as the 'imperial standard yard.' At the same time a brass weight which had been in the custody of the House of Commons since 1758 was adopted as the 'imperial standard troy pound.' But the avoirdupois pound was also officially recognized, the difference between the two being that the troy pound was defined to be 5,760 grains and the avoirdupois pound 7,000 grains. The 'imperial standard gallon' was made the official standard of capacity for both liquid and dry measure. Under certain standard conditions of measurement this was defined to be the volume of 10 avoirdupois pounds of water, or 227.274 cubic inches. The wine gallon of 231 cubic inches had previously been the standard of capacity since 1706.
​The subdivisions and multiples of these standards were such as to necessitate much confusion. The troy pound was divided into 12 ounces of 480 grains each, and the avoirdupois pound into 16 ounces of 437.5 grains each. The troy pound is less than the avoirdupois pound and the troy ounce greater than the avoirdupois ounce. A distinction has to be made additionally between dry ounces and fluid ounces. Various bushels and tons of widely different values continue in use. Although the original English standards were destroyed by fire in 1834, they were subsequently reproduced with reasonable accuracy. They are now the standards of the British empire with a total population of nearly 400,000,000 people, among whom a multitude of other unstandardized units of weight and measure are in current use.
The American colonies naturally employed such coins, weights and measures as were used in the mother country, and in no two of them were the 'systems' alike. A decimal system of currency proposed by Thomas Jefferson was introduced in 1792 and has continued in satisfactory use ever since. In taking this rational step the American republic set an example which has subsequently been followed by a large majority of the civilized nations of two hemispheres. Different monetary units are employed, such as the dollar, the franc and the florin, but the great advantage of decimal multiplication and division is almost universally recognized. The constitution authorizes congress to fix all standards of weight and measure for the entire country, and Mr. Jefferson urged the adoption of a decimal system for these as well as for our coinage. But this plan was not followed, and now after the lapse of a century American weights and measures are still in a state of confusion; some of them reasonably definite, others unintelligible except by the use of qualifying circumlocutions, and none of them connected by very simple numerical relations. A copy of the English yard was tentatively adopted in 1814 as the American linear standard. A copy of the troy pound was in 1828 made the standard of weight for the mint, and in 1830 the avoirdupois pound, deduced from the troy pound, was legalized as the standard of weight for ordinary commercial transactions. At the same time the wine gallon of 231 cubic inches was adopted as the standard of capacity for liquids, and the Winchester bushel of 2,150.42 cubic inches for solids. It will be observed, therefore, that the British gallon exceeds the American gallon by 20 per cent. The British bushel contains 2,218.192 cubic inches, and thus exceeds the American bushel by a little over 3 per cent. If we speak of a gallon or bushel, the meaning is thus not clear without further specification. But without reference to English units, or units that are obsolete or infrequently employed, we have in general use in America two different pounds, two different ounces, two different quarts, two different tons, two different miles, and a complex relation between linear, square ​and cubic measures, and between volume and weight. This diversity is not so confusing as it might be, because the foot and inch are perfectly definite in value, and a pound is generally understood to mean an avoirdupois pound.
In 1790, the same year in which Jefferson presented to American legislators his decimal system of coinage, weights and measures, Prince Talleyrand in France distributed among the members of the Constituent Assembly at Paris a proposal to found a new system of weights and measures upon some natural and invariable standard, with the hope that it might become a world system and thus displace the multitude of complexities which constituted a serious barrier to commerce. The cooperation of Great Britain was particularly desired, and a special invitation was conveyed to the British parliament to send commissioners from the Royal Society for the purpose of conference with a similar commission from the French Academy of Sciences. The British government withheld even the courtesy of an acknowledgment. Spain, Italy, the Netherlands, Denmark and Switzerland were represented in the conference. The result is now too well known for special recital. The metric system of weights and measures was born amid the throes of the French Revolution. With the reign of terror it had nothing in common. It was a model of simplicity and consistency, but it had two important elements of weakness. The first of these is found in the fact that there had been no popular demand for it. The second is that it was based on the false assumption that an absolute and invariable standard can be found in nature. Each of these elements is worth consideration.
The function of legislation in connection with science is to utilize science for the general welfare only so far as the people are prepared to accept improvement. In a community where ignorance prevails even sanitary science can not be enforced for the saving of human life from pestilence, unless military despotism is substituted for local self-government until the causes of pestilence are eradicated. Water as clear and sparkling as the freshest dew-drop may contain in solution tasteless poison that spreads typhoid fever or cholera among the ill-informed skeptics who are unwilling to be taxed for their own protection. The French people knew nothing of the branch of applied science now called metrology. They felt no evils as the outcome of a multitude of unrelated weights and measures, incomprehensible to most of the world. The new decimal system was easy to brand as the fiction of doctrinaires, just as the taxpayers in a fever-stricken community denounce and resist the officers of the law who close an infected spring of water. The logical outcome of the French revolution was the military despotism of Napoleon, and by this means the metric system was forced upon an unwilling people. The generation on whom ​the imposition was laid never really adopted it. The succeeding generations have been gradually losing the memory of the old weights and measures, and the inherent merits of the new system are such that relapse to the old barbarism is now impossible, whatever may be the modifications gradually imposed in practise upon a system of metrology which owed its existence to special creation rather than evolution. The case is quite comparable with the new era of sanitation in Cuba. Yellow fever has been almost wholly stamped out. The superiority of the new conditions is now recognized, and the Cubans will probably never return voluntarily to the régime of filth which fixed a scourge upon Havana for two centuries.
Prior to the French revolution various propositions and experimental attempts had been made to secure an absolute standard of length. In England Graham had tried to establish the length of a seconds pendulum as a standard, but without permanent success. In France several years were devoted by Delambre and Méchain to the determination of the length of an arc of the meridian between Dunkirk and Barcelona. The quadrant as computed from this survey was 10,000,000 times the length of the adopted standard, the meter. The outcome was no more absolute than any other product of human skilled labor. The opponents of the metric system have been fond of calling attention to the mistake in computed value of the meter. The labors of Bessel, Schubert and Clarke have established the existence of an error of about one part in 7,000. This means that the meter is shorter than it ought to be by an average hair's breadth; but this small error is quite sufficient to prove that the actual meter is an arbitrary standard. The fact is admitted as readily by the advocates as it is proclaimed by the opponents of the system. The most enthusiastic of these opponents have been the members of a small clique, led by the late Piazzi Smyth of Edinburgh, who claimed to have discovered in the pyramids of Egypt convincing evidence that the British inch is the only absolute unit, a definite fraction of the earth's polar diameter. Such conclusions are quite harmless ; equally unassailable and incapable of proof. The real merit of the metric system is found in its definiteness and simplicity, and not at all in any approximate relation between its fundamental unit and the earth's polar circumference, or any other terrestrial dimension, whatever may have been the intention of its originators.
The metric system was adopted in France in 1795 and made obligatory in 1801. The change was too sudden for the people and compromise was found necessary. The full enforcement of the law dates from 1840, and the system has since become gradually and quite thoroughly established. France is a republic, and the law would long ago have been repealed if good reason for such action existed. At the close of the Franco-German war an important step in the unification of the ​new German empire was the substitution of the metric system for the many widely different local systems of metrology. The German people are now accustomed to it, and there is no more danger of its abandonment in Germany than in France. A list of forty-three countries could be given, the governments of which have adopted the metric system. This includes the greater part of continental Europe and of the American continent south of the United States. It has been legalized, but not made obligatory, in the United States and Great Britain. In Denmark it has not yet been fully adopted, but is largely used in trade, in coinage and in the railway system. In Austria, it has been established since 1876 ; in Norway and Sweden since 1889 ; in Turkey since 1891. In all cases it is reported to have given great satisfaction to the commercial classes, the chief obstacle being the ignorance and consequent opposition of the peasantry. From a carefully prepared list it is found that the population of the countries that have adopted the metric system is now a trifle less than 500,000,000. In 1863 it was about 140,000,000. The number has been more than trebled in forty years. In Russia a decree looking to its general adoption has been prepared by the minister of finance, approved by the administrative council, and is now awaiting the signature of the Czar. Should this be given, the system receives an addition of over 100,000,000 people to be put in training.
In the United States the first general legislation on the subject of weights and measures was an act of congress in 1866, by which the use of the metric system was made lawful, but not obligatory. No recognition of the theoretic superiority of any system is ever sufficient to induce the people to discard the system to which they are accustomed, however cumbrous this may be. The law of 1866 might be defined as merely legislative politeness. In 1875 an international conference was agreed upon by the most important nations of the world with a view to the promotion of some common system of metrology. The result was the establishment of the international bureau of weights and measures at Paris, maintained jointly by the participating governments. The first object to be attained was the preparation of a new international standard meter and a new international standard kilogram, certified copies of which were to be furnished to each government. The preparation of these was the work of a number of years. The copies sent to the United States were officially adopted by Congress, April 5, 1893, as the American national standards. The yard is hence legally defined as a definite fraction of a meter, and the pound as a definite fraction of a kilogram. This was an important step, but was regarded by many as of no practical importance, the use of the British standards being still protected by law.
The next step forward in this country was the adoption, July 12, 1894, of eight units for the measurement of electrical magnitudes. ​Electricity as a quantitative science is founded on the metric system. The congress of electricians at Chicago in 1893 fixed the electrical units for the entire world, and these have been legalized by all the governments represented in that congress. In one branch of industry, of great and growing importance, the civilized world is thus united in the use of a common system of measurement. It would probably be hard to find an electrical engineer in England or America who is not in favor of the universal adoption of the metric system.
During the last dozen years there has been a growing popular demand among the commercial classes throughout the English speaking world for the general adoption of the metric system. This demand is not based on any theoretic ground, such as its simplicity and consistency, but on the commercial need of international uniformity. It would have no existence if all civilized nations used the British system. New markets can not be secured if customers are unable to understand the mode of measuring what is bought or must present their specifications in terms that are unsuited to the machinery employed in manufacture. Moreover, those who are already accustomed to a simpler system can not be expected to adopt in its place what is to them complex, unintelligible, indefinite and radically incapable of being made simple. Whatever may be the claims made by those who are accustomed to a bad system of metrology, or who have property that would be made valueless by its abolition, there is scarcely any conceivable prospect of the universal adoption of the British system. In the race for commercial supremacy there is little respect shown for theory, sentiment, old habits or corporate vested interests. The demands of trade must finally be met, even if vested interests should be strong enough to retard satisfactory legislation. The demand for international uniformity will continue to grow. The choice of the whole world has to be made between two systems of metrology, and only two, the British and the metric. All others have been practically eliminated from such a contest. If England and America should completely dominate the trade of the rest of the world the British system will be established; if not, it is doomed. Its total destruction will not be witnessed by any now living, but uniformity of weights and measures for the civilized world is as reasonably to be expected as was the establishment of Jefferson's monetary system throughout the union of American states.
In 1895 a select committee of the house of commons, after carefully considering commercial demands in England, urged upon the government that the metric system be at once legalized and that it be made compulsory by act of parliament after a lapse of two years. A deputation from thirty-nine chambers of commerce, including those of London, Edinburgh, Liverpool, Birmingham and Belfast, urged upon Mr. Balfour the importance of carrying out the recommendations of the ​committee. A large number of other associations representing many thousands of influential business men joined in the demand. Mr. Balfour admitted the merits of the metric system, but was unwilling that it be made compulsory in the near future, because he feared the effect on the small retail dealers and those who buy their goods from such dealers. He did not consider the British public yet ready for so important a change. The result was the legalizing of the metric system in Great Britain, but the defeat of the effort to make it compulsory. A great number of commercial associations, large and small, were added to the first list, and in not a single case did any body of wholesale or retail traders oppose the compulsory adoption of the metric weights and measures.
In 1896 a bill was introduced into congress at Washington for the compulsory use of the metric system in all departments of the government after July 1, 1898, and the adoption of it as the only legal system of weights and measures in the United States after January 1, 1901. This bill was reported favorably by the Committee on Coinage, Weights and Measures, but it was found necessary to delay action upon it. A second trial was made in 1902, and the committee secured the views of prominent representatives of a large number of different professions, trades and manufacturing interests. Of the many written communications, about nine tenths advocated the adoption of the metric system. Of the witnesses who appeared in person before the committee, which included 29 men of recognized standing in their respective callings, 23 were in favor and 6 of them opposed to the bill. Of the 6 opponents 4 represented large manufacturing interests involving the application of mechanical engineering, and 2 were connected with the revenue system of the government. The chief ground of opposition was the expense and inconvenience involved in making the change. Vested interests thus constitute by far the greatest obstacle next to conservatism.
Much could be written in this connection about the many considerations to be weighed by a congressional committee before reaching a final conclusion on a subject of such grave importance. The volume of testimony to which reference has just been made is a remarkably strong presentation of them. Any one who is enough interested to examine it can obtain a copy, gratuitously, by writing to the chairman of the Committee on Coinage, Weights and Measures at Washington.
Hon. J. F. Shafroth, of Colorado, has recently introduced a bill providing that after January 1, 1905, the metric system shall be made compulsory in all departments of the government in the transaction of business requiring the use of weight and measurement, except in completing the survey of the public lands, and that after January 1, 1906, ​it shall be the legal standard of weights and measures of the United States.
Should Mr. Shafroth's bill become a law, it is practically certain that a similar act will be passed by the British parliament soon afterward. Experience in Germany, Switzerland, Austria and other European countries within the last thirty years affords the assurance that, while temporary inconvenience may be expected, the transition will be soon accomplished in all important commercial centers; that persons of middle age and advanced years who have had no previous familiarity with the metric system will continue to use that to which they are accustomed; that the younger generation will everywhere appropriate and appreciate it; and that the agricultural population will be the last to become adapted to the change. Concerted opposition to the metric system by many whose capital would suffer depreciation by change is to be expected. The powerful influence of conservatism will be hard to overcome, however strong may be the arguments of those having commercial interests with Europe and South America. The passage of the metric bill may be again delayed. But the United States has become an exporting country and this necessitates two important changes. One is the removal of unnecessary tariff barriers to foreign trade. The other is the adoption of a system of weights and measures that is equally suited to domestic and foreign trade. Those who have been opposed to the recent American policy of forcible annexation of foreign countries have the partial compensation of knowing that it gives a strong impulse to the unification of weights and measures for the entire world. There may be honest difference of opinion among the advocates of the metric system regarding the advisability of assigning so early a date as 1906 for the legal establishment of this system in our country. Probably all of them will agree that 1905 is not too early a date for the exclusion of the old system and adoption of the new in the different departments of the government. The people will thus be induced to learn the metric system practically and compare its simplicity with the complexity of the system to which they have been accustomed. The opposition to it hitherto has come chiefly from those who have no practical acquaintance with it. They are quite excusable for thinking best to 'let well enough alone,' just as the majority of Englishmen would object to substituting our simple American system of decimal currency for their cumbrous system of farthings, pence, shillings, pounds, crowns and guineas. It is well to remember, moreover, that existing conditions in England and America are quite different from those under which Bismarck introduced the metric system into the newly formed German empire. From the Atlantic to the Pacific, from Mexico to the Arctic circle, there is but a single system of weights and measures, which has some few good features with its many bad ones, and which is ​factory to most of those who use it. Change in our system of metrology is not needed for political unification. Any legal enactment imposing a sudden change will be apt to arouse enough popular opposition to ensure its repeal before the people have had a fair chance to give an impartial test to the new system. A probation period of ten years in the government departments might perhaps be better than one year; or possibly it might be wiser at present to avoid specifying the length of any probation period. It would be better for the demand to come from the people at the end of thirty years than for a repeal of the law to be forced after it has been in operation only a short time.
Much has been said about the superiority of a binary to a decimal system. It is admitted that the decimal system is better for purposes of computation, but alleged that in the ordinary practical affairs of life people divide into halves and quarters more readily than into tenths. There can be no objection to the simultaneous application of both methods, so far as convenience may suggest. A binary system does not lend itself to decimal notation, while a decimal system does admit of limited, but amply sufficient, binary subdivision. This has been abundantly shown in the use of American money. Half-dollars and quarter-dollars, as divisions, are entirely satisfactory to all advocates of a decimal system. Our fathers coined eighth-dollars and sixteenth-dollars also, but nobody seemed to want them. Half-meters and quarter-meters as linear divisions are quite as good as half-dollars and quarter-dollars. Our idea of a quarter of a dollar is no less definite if it be called twenty-five cents. In like manner, no one can object to calling twenty-five centimeters either a quarter of a meter or a metric foot, agreeing in length with the human foot. That decimal subdivision is quite as natural as binary subdivision is shown by the universal American tendency to express profits and losses as percentages. If there is any real superiority in binary subdivision all dividends should be expressed in thirty-seconds, or sixty-fourths, or hundred-and-twenty-eighths.
It has been urged that a duodecimal system is better than either a binary or a decimal system. This may be granted, but its introduction would involve practical difficulties much greater than any connected with the general adoption of the metric system, including the abolition of the British system. Its consideration has no more practical importance than a proposition to substitute Volapuk for the English language.
The late Sir Joseph Whitworth expressed the opinion that the adoption of the metric system would be easy if its advocates would only lengthen the meter from 39.37 to 40 inches. This would make the inch rather than the meter our unit of length. Such a change would on many accounts be exceedingly desirable. But its consideration could be only the result of compromise in an international conference ​for this purpose. It would require the majority of the nations of the civilized world to change their standard, with all the expense that this implies, for the sake of saving expense to English and American mechanical engineers and capitalists. For the sake of international uniformity such a conference might well be undertaken, although with the assurance that the continental engineers and capitalists would not regard the subject from our standpoint.
Objection has often been made to the nomenclature of the metric system, which is thought to be too diffuse, too high sounding and scholastic to appeal to the masses. Such names as hectare and kilometer are unwelcome to the farmer, who is well satisfied with his acres and miles. There is no good reason to prevent any needed modification in nomenclature so long as the fundamental units and the decimal relation between them are preserved. In our decimal currency the eagles, dimes and mills are for the most part forgotten, while dollars and cents are enough for most purposes. No great inconvenience has resulted from the use of the word 'nickel' for a five-cent piece, or the alleged 'pennies' and Californian 'bits' in the nomenclature of small change. Those who are habituated to the use of the metric system rarely ever speak of decimeters or dekameters, or decigrams or myriagrams. The fathers could not provide for an indefinite future. Elasticity is necessary, and new subordinate units are certainly allowable as long as they serve any useful purpose.
In conclusion, those who advocate the introduction of the metric system will need to be patient and considerate. Those who oppose it must look to the future as well as the present. The well-worn query, 'What has posterity done for me?' is good enough for the local politician but unworthy of the statesman.