6G2 
]vni. AIET’S ACCOrZsT OF THE COXSTErCTIOX OF 
the authority of this original yard was called in question, he laid down, subsequently, a 
second yard marked Excheq.^ which he took with great care* from an old Standard of 
Elizabeth kept at the Exchequer as the legal Standard. These two yards were found 
by Geaham to be thus related 
Tower Yard E= Exchequer Yard ^a’c^C£. + 0“ -0075. 
“ This Tower Yard E is generally called the ‘ Royal Society’s Standard Yard,’ by the 
earlier authorities. 
“ I do not know when Bied made his original scale, but from his method of diriding 
mural quadrants, a well-divided scale must, I think, have been in his possession before 
the graduation of the Greenwich Mural Quadrant. In 1758 and 1760, he made two 
Standard bars for a Committee of the House, which are kno’UTi by those dates, the 
Standard of 1760 being in 1821 declared to be the legal Imperial Standard, which I am 
attempting to restore. I find, from some notices by Maskeltxe, in the Philosophical 
Transactions for 1768, pp. 324, &c., that Bied’s oim scale Avas just 0“ -001 in 3 feet shorter 
than Geaham’s Tower Yard Ef ; and I believe, though I have no absolute eAudence of 
the fact, that his own scale was the type followed by Bied in constructing his Standards 
of 1758 and 1760, and in fact all the scales Avhich issued from his hands ; so that Bied’s 
scales are, errors excepted, 0'" ‘001 shorter than Geaham’s ToAA^er Yard E. It is certain 
that Teoughton, in laying doAvn his oAvn scale, took the fundamental length from a scale 
by Bied (Philosophical Transactions, 1798, p. 137). Hence, as a general rule, all scales, 
haring Bied or Teoughtox for their authors, Avill be found to be about 0“ -001 shorter 
in 36 inches than Geaham’s ToAver Yard E ; although accidental eiTors, to half that 
amount at least, may occur in any of the older scales Avhich have been examined by 
Shuckbuegh, Katee, &c. 
“ If this account be, in the main, correct, Ave see hoAv it comes to pass that Shuckbuegh's 
scale by Teoughton should be nearly of the same length as Bied’s Standard of 1758 and 
1760, since they are all of the same family. The statements of Shuckbuegh and Katee 
as to the identity of the measures must be qualified, and Teoughtox’s belief in the 
perfection and similarity of his own scales cannot be fully admitted;|;. 
“ Another family of scales, viz. General Roy’s scale and Ramsdex’s scale, are said to 
have been carefully compared Avith Geaham’s ToAver Yard E, and to haA e agreed exactly 
with the Exchequer Standard, pages 548 and 550, their difference appeared to be — 0'’'"0075 
= 0‘'' '0036. But the Excliequer Standard (a rude end-standard) could not be very exactly compared; and 
it seems probable that the origin of the discordance is not in the inaccuracy of the transfer, but in tlie inac- 
curacy of comparison through the Exchequer Standard. — G. B. A. 
* That is, with as great care as the nature of the case permitted. The construction of the Exchequer 
Standard did not admit of accurate transfer. — G. B. A. 
t “ These are not Maskeltne’s very words, but his meaning applied to my oaa’u nomenclature.” 
X “ From SHTJCKBUEaH’s measures of the 6-inch spaces of his scale, we may gather that the yard (F"-, . .36'”' 
exceeded the yard about 0*"'’00045, and thC'G-incli space 30*'’-..,3G*'’- exceeded the G-inch space 
36'"'...42i"' by 0‘"--00053.” 
