140 FUNDAMENTAL UNITS OF MEASURE. 



reliable account dates back to tlie time of Henry VII (about A. d. 1400). 

 In tbe Transactions of tlie Royal Society it is recorded that in 1742 

 "some curious gentlemen, botb of tbe Royal Society of London and of 

 tbe Royal Academy of Sciences at Paris, tbinking it migbt be of good 

 use for tbe better comparing togetber tbe success of experiments made 

 in England and in France, projjosed some time since tbat accurate 

 standards of tbe measures and weigbts of botb nations, carefully exam- 

 ined and made to agree witb eacbotber, migbt be laid up and preserved 

 in tbe arcbivesbotb of tbe Royal Society bere and of tbe Royal Academy 

 of Sciences at Paris," and determined to bring about an excbange of 

 copies of tbe standards of weigbt and mass of tbe respective countries. 

 Tbis led to an examination of tbe original standards of tbe excbequer 

 and tbeir copies. It was found tbat tbe standard yard tben in use was 

 a square rod of brass, of breadtb and tbickness of about half an incb. 

 Tbe ends were neitber exactly flat nor parallel. Tbe standard was an 

 end measure and a matrix was provided for it. Near eacb end of tbe 

 yard was stamped a crowned E and it dated from about 15SS. Con- 

 sidered as a standard, its cbaracter was very inferior, but less so tban 

 tbe old standard of King Henry VII, wbicb was examined at tbe same 

 time. This is described as an '' old eigbt-sided rod of brass, of tbe tbick- 

 ness of about balf an incb, very coarsely made, and as rudely divided 

 into 3 feet, and one of tbese feet into incbes." Tbis is tbe standard 

 wbicb dates from A. D. 141)0, and is tbe earliest known material yard. 



In 1758, under instruction from a committee appointed by Parliament, 

 Jobn Bird constructed copies of tbe tben existing standanls (Eliza- 

 betban), one of wbicb, a line measure, was recommended for adoption 

 as tbe legal standard of lengtb. A copy of tbis was made by tbe same 

 artist in 1700, and is known as Bird's standanl of 17G0, to distiiiguisb 

 it from bis tlrst copies made in 1758. Altbougb tbe subject received 

 much consideration during tbe next balf century, it was not until 1824 

 tbat any actifm was actually taken by Parliament. It follows tbat up 

 to tbis date tbe legal standard of lengtb in(Jreat Britain and ber colo- 

 nies continued to be tlie very imperfect standard of Elizabetb referred 

 to above. In 1824, bowever, it was finally enacted tbat Bird's standard 

 of 17(jO sbould be tbe fundamental unit of lengtb, and in tbe same act 

 it was provided tbat in case of loss it sbould be reproduced by means 

 of its suj^posed known ratio to tbe lengtb of a seconds pendulum at 

 London. In 1834, tbe Parliament bouses, in (me of wbicb tbis standard 

 bad been pi;(^served, were destroyed by fire. It is interesting to note 

 tbat tbe conflagration was due to tbe burning of the " tallies" or sticks 

 on wbicb accounts bad been kept by means of notcbes, and in the use 

 of wbicb the Government officials bad persisted for many years after it 

 bad almost become a lost art elsewhere, thus exhibiting a conservatism 

 characteristic of tbe whole course of tbe English (lovernment in refer- 

 ence to metrology and allied sciences. 



Tbe legal standard having been destroyed in this manner, it was 



