18 
Captain Kater/s account of the 
Troy Pound No. 4. 
The mean of four comparisons gave 
— ,0022 4- ,004 — 
The mean of six other comparisons gave 
— ,0021 + j° 02 = 
The mean of eight other comparisons 
Grains. 
+ ,0018 
— ,0001 • 
+ ,0041 
Troy Pound No. 5. 
The mean of five comparisons gave 
- — - ,0044 4 " ,006 — “ 4 " ,0016 
The mean of seven other comparisons gave 
-—,001 4 “ >°° 2 — - 4 “ j ° oi ° 
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 was 
divided by the sum of the comparisons. In this manner the 
following errors of each of the troy pounds was determined. 
No. 1. 
- 
Grains. 
- 4- ,0005 
2 . 
- 
- —,0015 
3 - 
- 
4 " >0021 
4. 
- 
4" »° 022 
5. 
- 
4" >°oio 
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 
