new standards of weights and measures. 1 1 



The Imperial Troy pound is in the custody of G. Whittam, 

 Esq. Clerk to the House of Commons, who obligingly per- 

 mitted me to compare two weights with the standard at his 

 house in Abingdon-street. These being intended merely as 

 rough models for Mr. Bate to copy, it was not thought 

 necessary to waste time in adjusting them with the utmost 

 precision, and they were left a little in excess. 



The five Troy pounds being completed by Mr. Bate from 

 the copy of the Imperial pound taken at Mr. Whittam's, I 

 proceeded to compare them with the Imperial Troy pound, 

 which was then confided to my care for that purpose. The 

 balance employed in making the comparisons was made by 

 Mr. Robinson, an artist who has directed much of his atten- 

 tion, and with great success, to the improvement of this 

 instrument. The beam is only ten inches long, and toge- 

 ther with the scale pans weighs eight hundred grains. The 

 scale pans are attached to agate planes, which rest upon knife 

 edges. The ultimate angle of the central knife edge is 

 120 degrees. This balance, with one pound avoirdupois in 

 each scale, it may be seen by the following details, varies 

 immediately one division, equal to about one-tenth of an 

 inch, on the addition of one-hundreth of a grain. 



Adjustment of the standard troy pounds. 



In order to distinguish the troy pound weights from each 

 other, they were marked in the following manner : 



