702 PHILOSOP«ICAL TRANSACTIONS. [aNNO 1 743. 



same metal, brass, as none of the differences we are concerned about are very 

 great, and as the change of the weather was not very considerable between the 

 days of trial; it has been thought this last consideration might safely be neg- 

 lected, in setting down the following particulars. Which are, that 



The greatest length of the matrix of the yard measure, at the Exchequer, 

 exceeded the square standard yard by O rev, 8.'^ div. = . 0102 = -g^.Vs-- — The 

 yard inscribed on the Royal Society's rod, exceeded the same by O rev. 6.0 div. 

 = .0075 = T-rT.T- — The old brass standard at the Exchequer marked with the 

 crowned J^, fell short of the same by O rev. 5.7 div. = .007 1 = -ti-b-.t- — The 

 standard ell rod, at the Exchequer, exceeded 45 inches, of such as the standard 

 yard contains 36, by 1 rev. 19.5 div. = .0494 = ■^]-^^. 



At Guildhall, the standards of long measure there used, are only two beds, 

 or matrices, the one of a yard, and the other of an ell, cut out of two of the 

 edges of a substantial brass bar, much like that at the Exchequer, but not alto- 

 gether so thick ; which bar is sealed with the Exchequer seal, and marked at 

 both ends with c. r. crowned; and also, as it seems, with w. m. crowned in like 

 manner. But there are here no rods fitted to these beds; so that all that seemed 

 requisite and proper to be done, was to take both the greatest lengths of these 

 beds, and also the least lengths of the same ; the last being nearly the lengths 

 of such square rods as might be so fitted into the beds, as to go in every way 

 close, and without sensibly shaking; and, on taking the said measures, it ap- 

 peared, that 



The greatest length of the yard bed, at Guildhall, exceeded the standard 

 yard, at the Exchequer, by 1 rev. 14.7 div. = .0434 = tt.Vt- — The least 

 length of the same bed, exceeded the said standard of a yard by 1 rev. 1 1 .7 div. 

 = .0396 = -rT.T- — The greatest length of the ell bed, at Guildhall, exceeded 

 45 Exchequer standard inches by 1 rev. 15.5 div. = .0444 = -j-J-. — The least 

 length of the same bed exceeded the same number of like inches by 1 rev. 0.7 

 div. = .0258 = W.T- 



The standard of a yard, in the Tower of London, belongs to the Office of 

 Ordnance, and is kept in the drawing-room there; it is a solid brass rod, about 

 tIj. of an inch square, and about 41 inches long; on one side of which is laid 

 off the measure of a yard, divided into 3 feet, and each foot into 12 inches; 

 the first foot has the inches divided into lOths, the second into I2ths, and the 

 third into 8ths of an inch, and the first inch of all is divided into 100 parts, 

 by diagonal lines. This rod is said to have been provided by the late Mr. 

 Rowley ; it is sealed with the Exchequer seal, and two other seals of g. h. 

 crowned, near one of the ends, together with his Majesty's mark commonly 

 called the broad arrow. And the length of the yard, or of the 3 feet inscribed 



