18 



Captain Kater's account of the 



Troy Pound No. 4. 



The mean of four comparisons gave 



— ,0022 -f- ,004 = - - - 

 The mean of six other comparisons gave 



— ,0021 + ,002 := - - « 

 The mean of eight other comparisons 



Grains. 

 + ,0018 



— ,0001 

 + ,0041 



Troy Pound No. 5. 



The mean of five comparisons gave 



— ,0044 + ,006 =----}- ,0016 

 The mean of seven other comparisons gave 



— ,001 + ,002 = - _ - + ,0Q10 

 The mean of four other comparisons - - ,0000 



In order to deduce a final mean from these results, each 

 result was multiplied by the corresponding number of com- 

 parisons, and the sum of the products thus obtained vv^as 

 divided by the sum of the comparisons. In this manner the 

 following errors of each of the troy pounds was determined. 



Grains. 



These errors being so small and mostly in excess, it was not 

 thought necessary to make any attempt to correct them. 

 The five troy pounds previous to their being delivered to 



