2^6 Experimental Comparlfin of Standard Meafures. 



introduftion of the ftandard of Queen Elizabeth; but fuch as it is, 1 haye thought proper ta 

 examine it, and find it as follows: inches. 



On this rod, | or the ift foot, is equal to 1 1,973 °" Troughton's. 

 the 2d foot is - 1 1)948 



the 3d foot is - 12,047 Error, of difference 



Difference. of 3 fci.t. \ 



The mean foot is - 11,989 — ,011 — >Q33 



4 yard, or 18 inches- - = 17,94^ — >o54 — >i°8 



I yard, or 24 inches - =23,921 — ,079 — ,118 



-I yard, Or 27 inches - = 26,937 — ,063 — ,084 



|. yard, or 3I5 inches - = 31,443 — ,057 — ,065 



4.^ yard, or 33^ inches - = 33,665 — ,085 — ,091 



Entire yard, or 36 inches - r: 35,966 — ,034 — ,034 



And the mean prd - - = 35,924 Mean — ,076 



And, by fo much, Mr. Troughton's meafure is longeft. 

 And the probable error, in the divifions of this old ftandard, is about yl^ iach. 



(§• 53') I* ""^y "°^ ^'^ defirable to fee the comparative lengths of thefe various ftand- 

 ards and fcales, reduced to one and the fame meafure, viz. Mr. Troughton's. 



, . , , TT T7-TT /I J J r Inches on Differ- Probable error 



36 inches, on a mean, of Henry V IJ . Itandard of 1490, are Troughton's. cnce. in diviQons. 



equal to - - - - - 



., of ftandard yard of Elizabeth, of 1588 



, of ftandard ell of ditto, of 1588 



* of yard-bed of Guildhall, about 1660 



^___ * of ell-bed of ditto, about 1660 



I. * of ftandard of clock-makers' company, ^671 



, * of the Towrer ftandard, by Mr. Rowley, about 



1720 ... - - 36,004 + ,004 



of Graham's ftandard, by SifTon, of 1742, viz. 



line E - - 



of ditto, ditto, viz. line Exch. 



of Gen. Roy's (Bird's)" 



fcale 



all made probably 

 ■ ofMr. Aubert's, ditto, l^j,^^^.^^^ ^^^ ^^^^^ 



ditto 



of Royal Society's, 



1745 and 1760. 



ditto, ditto 



of Mr. Bird's parliamentary ftandard, of 1758 



of Mr. Troughton's fcale, in 1796 



• Thefe Four quantities are taken from Mr. Graham's account, in the Thil. Tranf. vol. XLII. 



Fronj 



