WEIGHTS AND MKASl'KKS, STANDARD. 



WEIGHTS AND MEASURES, STANDARD. 



pert of n inch. The apparatus u dencribed ia Mr. Baily'n ' Report to 

 the Royal Astronomical Society on their Standard Scale ' (published 

 in the ninth volume of their Memoir*), from which much . i ti.,- 

 pretent article U taken. 



The first attempt* to be scientific in matters of measurement made in 

 this country date from the beginning of the 1 7th century. Previously 

 to this time men of information probably believed that the Roman and 

 Kngliah foot were the same, and that the pound troy was deducibli- 1 1 . >m 

 the Roman Libra. Bishop Tonatal, in hit Arithmetic (1622), where he 

 only treats what U necessary for common life, " ad vitam communem 

 tnmaigendam neceacaria," cites Columella on measures of length, 'and 

 deduces the system of coinage from Budmus on the Roman As. The 

 other writers of the same century pass over the mode of obtaining 

 measures, as if it were perfectly fixed, and generally refer to the three- 

 barleycorn inch as a standard. In the early part of the 17th century we 

 find Oughtred (' Circles of Proportion,' pp. 55-57) referring to actual 

 measures of the con tents of the gallon made by the celebrated Briggs, and 

 also by one William Twine, but taking the Roman foot as " very little 

 less, if not exactly the same," as the English foot. Later in the 

 century, Dr. Wybard (' Tactometria,' p. 268, published in 1650) gives 

 an account of experiments, at which he was present, for the determi- 

 nation of the same gallon ; and later still, in 1688, we have the 

 experiment with the same object [GALLON], at which Flamsteed and 

 lialley were present, which is referred to in the Report of the Com- 

 mittee of the House of Commons in 1758. As far as measurements 

 are concerned, had it not been for Greaves [GREAVES, JOHN, in Bioo. 

 Drv.J, we might have summed up the efforts of the 1 7th century by 

 saving they were mostly directed to finding, within one, how many 

 cubic inches there were in the several gallons. Greaves first directed 

 attention to the difference between the Roman foot and the English, 

 by tolerably accurate determinations of the former. [WEIOHTS AND 

 MEASURES.] He also attempted the investigation of the Roman 

 weights, and must be considered as the earliest of the scientific 

 metrologista. He was followed by Dr. Bernard [BERNARD, EDWARD, 

 in Bioo. Dry.], whose treatise on ancient weights and measures (1685 

 and 1688) must have given a great impetus to the spirit of comparison. 

 A work of this kind soon shows its consequences: Jeake's 'Arithmetic' 

 (folio, 1696) contains a hundred pages on the subject. Towards the 

 end of the century the measures of Auzout and Picard awakened 

 attention to the comparison of standards in France. Roth countries 

 were thus prepared to desire some information from each other on the 

 subject of their measures ; and a communication took place in 1742 

 between the Royal Society and the Academy of Sciences for an inter- 

 change of standards. Then, for the first time, as far as we can learn, a 

 yard was taken off on a brass rod from a standard kept in the Tower 

 of London (which we believe is not now in existence). But the legal 

 standard, usually so considered, was one which was kept at the 

 Exchequer ; there was another at the Guildhall, and another in the 

 possession of the Clockmakers' Company. When these came to be 

 compared with one another and with the Exchequer standard by 

 Graham (who also laid down an Exchequer yard on the same brass 

 rod), it appeared that the shortest and the longest differed by seven- 

 hundredths of an inch, a little more than the height of an o or an a in 

 this work. But had the difference been greater, it would not have 

 mattered much, considering the way in which standards were to be 

 used. In our own day, after nearly a century of communication 

 between statesmen and philosophers on the subject of a uniform 

 measure, Mr. Baily visited the Exchequer standard (from which the 

 copies we shall presently mention were made), and his account (Report 

 above cited, p. 146) is as follows : " Since the preceding sheets were 

 printed, I have had an opportunity of seeing this curious instrument, 

 of which it is impossible at the present day to speak too much in 

 derision or contempt, . A common kitchen poker, filed at the ends in 

 the rudest manner by the most bungling workman, would make as 

 good a standaid. It has been broken asunder, and the two pieces have 

 been dovetailed together, but so badly that the joint is nearly as loose 

 as that of a pair of tongs. The date of this fracture I could not ascer- 

 tain, it having occurred beyond the memory or knowledge of any of 

 the officers at the Exchequer. And yet, till within the last ten years, 

 to the disgrace of this country, copies of this measure have been circu- 

 lated all over Europe and America, with a parchment document 

 accompanying them (charged with a stamp that costs SI. I0t., exclusive 

 of official fees), certifying that they are true copies of the English 

 ttandard." 



In 1 758, a committee of the House of Commons began to investigate 

 this subject, and was followed by another in 1759 : both committees 

 made full Report*. Both . committees caused to be made, by Bird, a 

 copy of the Royal Society's (or Graham's) copy of the Exchequer stan- 

 dard, and these copies, which remained in the official possession of the 

 Speaker of the House of Commons, were called Bird's parliamentary 

 standards of 1758 and 1760 : it should be stated, however, that the 

 latter was only a copy of the former. The Reports were agreed to by 

 the House : a bill was brought in, according to their recommendation, 

 namely, that Bird's standard of 1758 should be the national standard; 

 but it was not carried through. A committee, appointed in 1 790, did 

 nothing, and the matter was thus abandoned. Private individuals and 

 scientific societies began to provide themselves with standards 

 Shuckburgh ( PhiL Trans.,' 1798) had one made by Troughton, which 



ha compared with the parliamentary standards and other*. Troughtou 

 made one for himself, and first introduced the micrometer micro- 

 scopes into the comparisons ; this last was made from one which Bird 

 had made for the then assay-master of the Mint. Another was nude 

 for General Roy, and was used by him in the great survey ; another. 

 Bird's own private property, was in existence. Thus matters want on 

 until the year 1814, when the House of Commons again appointed a 

 committee to consider the subject. 



In the meanwhile however experimental philosophy had made great 

 advances, and investigators began to look more at the successes of the 

 I ast than at the new difficulties which those very successes had opened 

 into view. As soon as the measurements of the earth began to be 

 attended with some success, the French proposed a standard measure 

 which should be the ten-millionth part of a quarter of the meridian ; 

 which last they hoped, by their great survey, to ascertain so exactly 

 that no future measurement should make even a microscopic alteration 

 of their new metre. In England the pendulum began to be considered 

 a perfect instrument ; and the second being determined invariably by 

 the motion of the earth, it was thought that the length of the seconds' 

 pendulum in a given latitude would be an invariable quantity which 

 could always be recovered. The committee of 1814, on the ev 

 of Playfair and Wollaston, recommended that Bird's standard of 1758 

 should be the one adopted, ami gave it as their opinion that the length 

 of a seconds' pendulum in the latitude of London is 89'13047 inches, 

 of which the above-named standard yard contains 36. Playfair and 

 Wollaston hinted at the necessity of verifying this number, but the 

 committee take it for granted, and assert that any expert watchmaker 

 can make a seconds' pendulum, without stating how that pendulum ia 

 afterwards to be measured, nor at what temperature, pressure, Ac. it 

 is to be swung. They also state that a cubic foot of pure water at 

 56) Fahr. weighs exactly 1000 ounces avoirdupois, as the connecting 

 link between measures of weight and capacity. No bill was brought 

 in consequence of this Report. 



In 1819 the Prince Regent appointed a commission composed of Sir 

 J. Banks, Sir G. Clerk, Davies Gilbert, Wollaston, Young, and Kater. 

 This commission made three Reports, dated June 24, 1819, July 13, 

 1820, and March 31, 1821. In the first (we confine ourselves to 

 matters affecting the standards) the standard yard recommended is 

 that on the scale used by General Roy in the measurement of his 

 Hounslow Heath base, and it was the opinion of the reporters that the 

 mean solar seconds' pendulum in London, at the level of the sea, in a 

 vacuum, and at 62 of Fahr., was 39*1372 inches of this scale. They 

 also take 19 cubic inches of distilled water at 50 to be exactly 10 

 ounces troy. In the Second Report, they announce that an error lias 

 been discovered in their standard, and they propose that Bird's 

 parliamentary scale of 1760 shall be the standard, the seconds' pendu- 

 lum being 39*13929 inches. In the Third Report, they announce, by 

 new experiments, that a cubic inch of distilled water at 62 is 252*72 

 grains of the standard pound of 1 758, when weighed in a vacuum. 

 The House of Commons again appointed a committee in 1821, to which 

 these Reports were submitted : this committee agreed with the com- 

 missioners, and a bill was introduced in 1823. A petition from the 

 Chamber of Commerce at Glasgow to the House of Lords occasioned 

 an investigation in that House also ; Dr. Kelly, one of the witnesses 

 before the committee, called attention to the known effects of variety 

 of attraction on the pendulum, as shown by Captain Kater's own 

 observations, and to the insufficient manner in which the level of ilif 

 sea was known : and bis opinion was that of few others at the time, though 

 now nearly universally received, namely, that " nature seems to refuse 

 invariable standards ; for, as science advances, difficulties are found to 

 multiply, or at least they become more perceptible, and some appear 

 insuperable." The House of Lords adjourned the question over till 

 1824 ; when the act 5 Geo. IV. c. 74, was passed, from whirli extracts 

 will presently be made. This act was to take effect May 1, 1825. Imt 

 in the March of that year ti Geo. IV. c. 12, was passed, deferring the 

 operation of the preceding act till January 1, 1826. There was 

 an inquiry before the House of Commons in 1834, which ended in the 

 statute of 4 & 5 Will. IV. c. 49, and another inquiry before the same 

 House in 1835, which ended in 5 4 6 Will. IV. c. 63, repealing the 

 former act and substituting new provisions. These last acts however 

 contain nothing with reference to the standards, except the following 

 excellent wind-up of the chequered and ill understood legislation upon 

 weights and measures. The Houses of Parliament were burnt in 1834, 

 and with them Bird's standards of 1758 and 1760 (the last Me standard). 

 Nevertheless 5 & 6 Will. IV. c. 63, passed after the fire, takes no 

 notice of the destruction of the standard, but refers to it as still in 

 existence. Seven years * ham since elapsed, but we are not aware of 

 the legislature having yet swung the pendulum to recover the lost 

 measure. 



As to the standards, the act prescribes as follows : 



1. The straight line or distance between the centres of the two points 

 in the gold studs in the straight brass rod now in the custody of the 

 clerk of the House of Commons, whereon the words and figures 

 " Standard yard, 1760" are engraved, shall be the original and genuine 

 standard of that measure of length or lineal extension called a yard . . . 

 the brass being at the temperature of sixty-two degrees of Fahrenheit' i 



* Thli WM written by .Mr. sheepshanks in 1641. 



