THE

AMERICAN COLLEGE

VOL. I

FEBRUARY, 1910

No. 5

THE ESTABLISHMENT OF UNITS

AND STANDARDS

By HERBERT T. WADE

THE question of units and standards is one usually considered as obvious, for their use is so necessary that their evolution, and especially the fundamental principles underlying their derivation, often receive but scant attention. Not only does all scientific knowledge depend upon measurement, but also commerce and in fact every department of life where comparisons or values are involved; for measurement and valuation are essentially processes of comparison, and a given quantity must be stated in terms of a second quantity which by common consent is taken as a unit, and which when realized in some concrete form for useful application becomes a standard. Now the development of units and standards has been contemporaneous with the intellectual progress of the human race; units and standards being evolved as occasion demanded, and improved or supplanted with the growth of scientific thought and method. Applied as they are in ordinary life with but little thought of their origin and direct significance, yet the derivation and preservation of various units and standards has been one of the most important tasks of scientific men and economists, and their improvement in the interest of accuracy and national or international uniformity is always an important question. In fact by international agreement the leading nations of the world maintain on a piece of ground, made absolutely neutral and under their joint control, an international bureau to care for the primary standards of weight and other measures, and to conduct scientific researches looking to their maintenance in their original integrity. In addition this bureau, which is located in one of the suburbs of Paris, prepares secondary standards and gives constant attention to the investigation and discussion of all fundamental problems in metrology, whether of practical utility or of mere theoretic interest. Aside from this international bureau each of the large nations maintains establishments known as bureaus of standards, offices of weights and measures, or national physical laboratories, where national standards are maintained and similar work is done for the scientific and manufacturing

interests of the country. Finally individual states and smaller communities provide facilities for securing the uniformity of weights and measures so indispensable to industry and commerce.

Thus bringing to mind that the subject of units and standards is an ever-present problems it is of interest to consider just how a policy of uniformity and standardization has developed, especially in its more recent phases. For example in the case of the units of weight and length there has been considerable progress in this respect since the end of the eighteenth century when the word pound was applied in Europe to 391 different units of weight and the word foot to 282 different units of length. To-day the international kilogram has superseded over 370 of these different pounds, and the meter, and to a less extent the British foot, a corresponding number of these feet.

In the early days of civilization primitive man was forced to evolve a system of units and standards for his daily life, and their development came naturally and in much the same manner as the ideas of number and language. Soon after the idea of number had been attained in this epoch of primitive culture, a comparison between objects as to their weight or dimensions, between distances, between intervals of time, between the capacities of different baskets, earthenware or other utensils, and other similar quantities gradually would be made, and after being applied in the daily economy of the individual or tribe would figure in the rude commerce of the time. The unit of value in remote antiquity was apparently the ox or cow, and after a man's family and slaves were considered, his wealth was estimated by the number of oxen or cows he possessed. These were used as a standard of value in the purchase or exchange of various commodities. The reason for this was that cattle were universally distributed and were approximately uniform with but slight variation among the individual animals, and what is essential they were universally known and understood by the members of the tribe and their neighbors. Next after the ox or the cow as a unit of value probably came gold on account of its uniform scarcity, and for its measure were taken either seeds, when it was weighed in a simple form of balance, or quills when it was measured by a unit of capacity, or some linear unit when the metal was hammered out in the form of strips or wire. The idea of the seeds survives in the modern grain of the Anglo-Saxon measures and the carat (from the Arab carob bean) used in measuring precious stones. The seeds were both units and standards of weight just as the quill or a gourd became units of capacity, and some linear measure, such as the finger or palm breadth, became a standard for the measure of gold wire. Of quite as much practical utility, but bearing less perhaps on commerce, were the primitive measures of length derived from the human body. Thus the foot was a convenient unit, as were likewise the fore-arm or cubit, the step or single pace, the finger, the palm or hand breadth, and the fathom or distance between the extended arms. It was

also appreciated that these various units bore a relation to each other so that here was a system of units complete in itself. Now with the foot for a unit. it was very important as soon as any approach to exactness was required, as in masonry work or carpentry, to define the foot to be used and mark it off on some surface for use as a standard. Manifestly there would be a difference in the length of the foot of a man five feet two inches in height and that of one six feet or more. The pace of the former would be quite a different quantity from that of the latter, and when used in the measure of land would be the source of striking discrepancies. Consequently it was inevitable that a certain foot should be taken as a standard either by common consent, or what was more usual by the decree of headman, chief, high-priest or king, and then this foot or other unit reproduced in some permanent and concrete form as on a stone monument or on a wooden measuring rod. Such standards frequently were entrusted to the priests and were located in the temples from which they have been excavated for modern study. They illustrate what has always been an interesting circumstance in the history of weights and measures, that units and standards were fixed by decree or edict, and in such units as the "black cubit," which figured in an important early measurement of the earth made under Caliph Al Mamun, the distance represented according to tradition the length of the arm of a favorite black slave. Tradition also assigns the origin of the length of the English yard to the length of the arm of Henry I. Latter day standards tho on hardly as arbitrary a basis as these were promulgated by the various rulers, and even in the United States more has been done by executive orders towards establishing accuracy and national uniformity of standards than by exercise of that power of regulating weights and measures specifically conferred on Congress by the Constitution.

In such ways as we have outlined each nation developed one or more systems of measures to suit their needs and purposes, which were arranged on a binary, decimal or duodecimal plan according to their systems of mathematical reckoning. The standards representing the units of the systems became no longer objects of priestly care but were either retained in royal mints or treasuries, or in the case of standards of length, in addition to metal or wooden bars, the distance between stones or plugs, as in the wall of a public building, might be legalized for this purpose. Such standards differing in various countries and even in different cities of the same country sufficed for the limited commerce of the middle ages and the centuries immediately following, and the middlemen or merchants buying by one system of units and selling by another were called upon to make the transformations, which were accomplished usually with due profit to themselves. But there were no standards between countries or, as we have said, often between different sections of the same country. In fact in an old chronicle of Saxon times* we find the statement,

*Bishop Fleetwood, Chronicon Preciosum, London, 1748 p. 27.