774 PROF. W. H. MILLER ON THE CONSTRUCTION OF THE NEW STANDARD POUND. 
Then, original error of K=+0'006 grain. Error of K in 1829 = original error 
+ 0’014 grain (wood) +0'014 grain (oxygen) = +0’034 grain. Error of K in 1844 
= error of K in 1829 —0‘014 grain (wood) +0'd08 grain (oxygenj = +0'028 grain. 
The comparisons of the troy pounds Ex, L, Ed, D with each other in 1814 give 
Ex+0 0102 grain =L+0"0061 grain =Ed = D. 
This result agrees with the conclnsion already derived from the comparison of Ex, L, 
Ed, D with Sb and K, in showing that the differences between Ex, L, Ed, and D 
have very sensibly changed in the course of twenty years. 
The troy pound R, which is much tarnished, is about 0*012 grain lighter than U, 
and therefore cannot be either of the weights used by Captain Kater in finding the 
errors of K and Kn. 
The discrepancies presented by the weighings of the brass troy pounds at different 
times, due to the effect of oxidation or other causes, are so large, that I resolved, with 
the consent of the Astronomer Royal, to rest for the evidence of the weight of the 
lost standard entirely on the comparisons of the two platinum troy pounds Sp and 
RS. In a note appended to Professor Schumacher’s paper in the Transactions of the 
Royal Society for 1836, p. 471, Mr. Baily observes, that, for some unexplained reason, 
Mr. Cary, who was commissioned to construct the troy pound RS, used for this pur- 
pose some platinum of his owm instead of that which was supplied to him by the 
Royal Society. The exchange, whatever may have been the cause of it, does not 
appear to have been detrimental, for the surface of RS, though certainly inferior to 
that of the newly made platinum kilogrammes and metre bars which 1 saw in Paris 
in 1844, is superior to that of Sp, in which plugs have been inserted to fill up holes 
left by drilling out defective .places, and is much better than that of the other pound 
weights made since of platinum prepared in England. 
If we consider tl)e discordances presented by the weighings of the brass troy 
pounds simply as errors of observation, without paying any regard to their* pt*obable 
causes, the resulting value of U will not be very different from that given by the 
platinum troy pounds alone. 
By the observations of 1824 and 1829, — 
gr. weight. 
U= Sp +0-0081 30 
U= RS + 0-0030 14 
U= Sb +0-0103 6 
U= K -0-0339 9 
U=REx + L + Ed + D)-0-0022 6 
By the observations of 1844, — 
gi*. 
RS =Sp +0-0057 
Sb =Sp +0-0030 
K =Sp +0-0363 
Ex + L + E(l + D=2(Sb + K) + 0-0260 
Whence, supposing the errors of the weighings to be insensible compared with the 
discordances of the brass troy pounds, — 
