VOL. XLIl.J PHILOSOPHICAL TRANSACTIONS. 703 



on it, exceed the forementioned Exchequer standard of a yard, by O rev. 8.9 

 div. = .011 1 = -tV- 



The standard yard, belonging to the Clockmaker's Company, was delivered 

 to ihein from the Exchequer, by indenture, the 4th of September, 23 Car. II. 

 A. D. 1671. It is a brass rod of eight sides, near half an inch in thickness, 

 sealed with the Exchequer Seal, and c. r. crowned, near each end ; and on 

 which the length of the yard is expressed, by the distance between two upright 

 pins, or small cheeks, filed away to their due quantity : this was procured by 

 Mr. Graham, to be brought to the president's house of the Royal Society, on 

 Saturday the 7 th of May last, where all the above-named Company then met, 

 to collate their respective notes of these several trials, all which were found to 

 agree with each other : at which last meeting, Mr. John Machin, of Gresham 

 College, the other Secretary of the Society, was present also : and the length 

 of this last yard measure was then tried, and found to fall short of the Exchequer 

 standard yard measure, now very carefully added on the middle line of the 

 Royal Society's brass rod, O rev. 16.8 div. = .021 = xt'.-bt- 



Now, as to the weights, those in the Chamberlain's Office in his Majesty's 

 Exchequer, and which are esteemed the standards, are a pile, or box, of hollow 

 brass Troy weights, from 256 ounces downwards, to the l6th part of one 

 ounce, all severally marked with a crowned e: but they have no penny- weights, 

 nor grain weights, that are any ways considered as standards. 



The weight mentioned in all our old acts of parliament, from the time of 

 King Edward the First, is universally allowed to be the Troy weight, its pound 

 consisting of 12 ounces, each containing 20 penny- weights : and as the pound 

 is the weight of the largest single denomination commonly mentioned in those 

 acts, 12 ounces taken from the pile of Troy weights abovementioned, as there 

 is no single Troy pound weight, must now be reputed the true standard of the 

 Troy pound, used at this day in England. 



Besides which Troy standards, there are also kept in the Exchequer the fol- 

 lowing standards for Avoirdupois weights: that is to say, a 14 pound bell weight 

 of brass, marked with a crowned e, and inscribed 



XIIII. POVNDE AVERDEPOIZ. 

 ELIZABETH. REGINA. 



1582. 

 As also a 7 pound, a 4 pound, a 2 pound, and a single pound, like Avoirdupois 

 bell-weights, and severally marked as follows, excepting the variations for the 

 number of pounds in each respective weight. 



