60 J. F. Tennant— Ort Standard Weiglts. [No. 1, 



3rd, on the error due to the fraction of P. 03 which is involved in 



its determination, 

 4th, on the error generated in the weighings of the series. 

 The following Table shows the error from each source separately. 



Weights. 



Squares of Probable Errors from 



Probable 

 Error x 106. 





Equil. 

 Weights. 



p 



■"-•0 3 



Weighments 

 of Series. 



Total. 



• 0, 



52900 



5225 



1179 



514116 



573420 



757 



0; 



119025 



5225 



449 



685488 



810187 



900 



0. 



211600 



11968 



2259 



1199600 



1425427 



1194 



0. 



330625 



18624 



4747 



1713720 



2067716 



1438 



0.0 



1922500 



47022 



47581 



5826648 



7813751 



2795 



In making these calculations, I have neglected to attend to the fact 

 that the P weights used have a common origin ; the sum of the squares 

 of the probable errors given in the Table at the end of Section VIII 

 is taken, and here (as will be seen by turning back) the error from their 

 common origin O. ^ is unf elt, but this is not always the case. 



Among the weights in the Assay Office is a bronze Standard Troy 



Pound in a wooden case, on which case is stamped | p^^^^ | > in ink 

 is written 



J. Prinsep. ") 

 Std. 1 a 5 

 On the weight itself is engraved — 



British Troy Pound, 

 = 5760 grains. 

 aSogal JTunt. 



The surface of the weight is thinly oxidized, but it seems to be quite 

 uninjured. I some time ago compared it, as well as I could, with the 

 weights of the Gilt Troy set belonging to the Assay Office, which were 

 supplied many years ago, and which were made by Bates in 1824. No 

 record of any previous comparisons of these exists. The conclusion I 

 came to was, that Prinsep's Troy Pound was about a mean of all the Gilt 

 Pounds, the latter weights having sensible errors, I have then thought 

 it worth while to determine the value of the Prinsep's Pound, and I find — 

 Prinsefs Pound = O^^ + 0^ + + P.^^ — 0-487 P. 03 



= 5760-148354 grains, 

 from a single complete comparison. 



