664 
ME. AIET’S ACCOUNT OF THE COXSTEUCTIOX OF 
Shuckbuegh’s scale are not very numerous nor veiy consistent. Those between the 
Imperial Standard and the Ordnance iron bars, A1 and A2, are singularly discordant. 
“ I ought to mention that I selected my terms of comparison 'with the Imperial Stand- 
ard, a])riori, on my otvn opinion of then- value from then’ history. I have not compared 
any scale which appeared to me suspected, for I should not have known how to estimate 
the weight, and mere discordance would not have justified rejection. 
“ Some details and some steps of my comparisons will be found m the Appendix Xo. 3. 
From these I deduce the following approximate value of the lost Standard : — 
“ 1st. From Shuckbuegh’s scale 10'"- . . 46‘“': — 
in. in. in. 
Brass bar 2 = Shuck. 10 — 46 + 0-000222 , 100 Ohs. (Appendix Xo. 3.) 
Shuck. 10‘“- — 46-" =Imp. Stand. + 0-000058 (Mem. R. A. S. vol. Lx. p. 120.) 
.-. Brass bar 2 = Imp. Stand. +0-000280 
“ 2nd. From Shuckbuegh’s scale 0‘“- . . 36‘“- : — 
in. in. in. 
Brass bar 2 = Shuck. 0 — 36 — 0-000006 , 120 Ohs. (Appendix Xo. 3.) 
Shuck. 0'"- — 36'"-=Imp. Stand. +0-000090 (Phil. Trans. 1830, p. 377.) 
.-. Brass bar 2 = Imp. Stand. +0-000084 
“ I have taken Katee’s last value as most worthy of confidence, but I do not much 
trust it, on account of the objectionable mode of resting the microscope apparatus upon 
the scale. 
“ 3rd. From Katee’s scale, made for the Royal Society 1831 : — 
in. in. 
Brass bar 2 =Katee’s scale 36+ 0-000849 , 110 bisections. 
Katee’s scale 36-"-= 35-999380 (Phil. Trans. 1831.) 
.-. Brass bar 2= 36-000229 
“ I have given the values of Brass bar 2 in terms of Imperial Standard from compari- 
sons with A1 and A2 in Appendix Xo. 3. 
in. in. in. 
“ Hence Brass bar 2 = 36-000280 by Shuckbuegh 10 . . 46 and comparisons in 1834, 
= -000084 Shuckbuegh 0 . . 36 and ILatee’s authority. 
= -000229 Katee’s scale. 
= -000303 Al, compared in 1834. 
= -000275 A2, compared in 1834. 
= 36-000234 by a mean of all. 
“ This should be pretty near the truth ; but I prefer 36-00025, if in such a matter such 
a difference be worth notice. 
“ 1 propose, therefore, in constructing- the new standards, to assume that 
Brass bar 2 = 36“' -00025 of lost Imperial Standard at 62° Faheexheit, 
and to make that the base of my future proceedings. 
“ Jw/y 18, 1848. 
“ R. Sheepshaxks. 
