VOL. XLII.] PHILOSOPHICAL TRANSACTIONS. 705 



Again : the single bell Avoirdupois pound, with the less scales, on the mediuui 

 of two experiments, counterchanging the weights, the basins not being move- 

 able, was found to weigh 14 Troy ounces 11 penny-weight and IS grains; or 

 was equal in weight to 7002, and the ounce to 437.62 Troy grains. 



The single Avoirdupois bell pound, against tne flat Avoirdupois pound weight, 

 was found, on a medium of two like experiments, to be heavier by two Troy 

 grains and a half: whence the fiat Avoirdupois single pound weight weighs only 

 699Q.5, and the ounce 437-46 Troy grains. 



The Royal Society's Avoirdupois pound was, in like manner, found to be 

 lighter than the Exchequer single bell pound weight, by one grain. 



And their Troy pound weight to be lighter than the 8 and 4 ounce Troy 

 weights at the Exchequer, taken together, by half a grain. 



The Founders' Company of London are, by their charter from King James 

 the First, authorized and directed to have the sizing and marking of all manner 

 of brass weights, to be made or virought, or to be uttered, or kept for sale, 

 within the city of London, or 3 miles from the same. And the weights de- 

 livered to them from his Majesty's Exchequer, and now kept in their hall, as 

 their standards for the uses abovementioned, are a pile of flat brass Troy 

 weights, from 256 ounces, down to the l6th part of an ounce, all sealed with 

 the Exchequer seal, and marked with c. r. crowned l684, and a stamp of the 

 initial letters of the maker's name: as also a set of bell brass Avoirdupois weights, 

 sealed and marked in like manner. And here the following trials were made, 

 before the abovenamed gentlemen, by Mr. Read, but with a large balance, com- 

 monly used for trials at the hall, in their office for that purpose ; and found to 

 turn with about the same weight as the former ; and also with a less one, turn- 

 ing in like manner under these circumstances, with about half a grain, which 

 balance belonged likewise to the hall, as did also the penny and grain weights 

 made use of, but which were not kept by them as standard weights. 



And here it was found on a medium of 4 trials, made in like manner as be- 

 fore, at the Exchequer, that 15 pounds Avoirdupois, being their 14 pounds, 

 and single pound standard weights, were counterpoised by 218 Troy ounces, 15 

 penny-weight and 23 grains : whence the Avoirdupois pound is deduced equal to 

 7001.53, and the ounce to 437.59 Troy grains. 



Again : the single Avoirdupois standard pound weighed, on a medium of 2 

 experiments, counterchanging the weights, as before, 14 Troy ounces, ll 

 penny-weight, 164 grains : or was equal to 7000.5, and the ounce to 437.53 

 Troy grains. 



Again : this standard Avoirdupois pound, at a medium as before, outweighed 

 the Royal Society's Avoirdupois pound, by 2 grains and -J^th : and the Troj 



VOL. VIII. 4 X Q 



