700 PHILOSOPHICAL TRANSACTIONS. [aNNO 1743. 



brass, of the breadth and thickness of about half an inch ; the one called the 

 yard, and the other the ell. The ends of neither are exactly flat and parallel, 

 or, if they were so once, they have since suffered some bruise or damage, and 

 that possibly by the impressing near each end the seal of a crowned e; by 

 which it appears, they were placed here during the reign of Queen Elizabeth, 

 and probably at the same time when the several standard weights, hereafter 

 mentioned, were lodged here also. 



To tiiese rods there belongs a substantial brass bar, of about the length of 

 •19 inches, the breadth of an inch and a half, and the thickness of an inch: on 

 one edge of this bar is a hollow bed or matrix, fitted to receive the square rod 

 of a yard: and on another, a like bed fitted to receive that of an ell; and into 

 these beds they usually fit the yard and ell measures brought to be examined 

 and sealed at this office. The square yard and ell rods fit sufficiently well into 

 these respective beds, so as neither to rub or shake very sensibly ; yet as neither 

 the ends of the rods, or of the hollow beds, are accurately flat and parallel, the 

 greatest lengths of those beds must, of necessity, be somewhat greater than 

 the greatest lengths of the rods intended to be placed in them: by which 

 greatest lengths of those rods, and which were considered by all the gentlemen 

 present, as the real and proper lengths of those rods, are meant the distances 

 of 1 parallel planes or cheeks, so placed as to touch the rods respectively at 

 both ends. 



Besides all which, there also remains in this office an old 8-sided rod of 

 brass, of the thickness of about half an inch, very coarsely made, and as 

 rudely divided, into 3 feet, and one of those feet into 12 inches. This is 

 marked near each end with an old English J^ crowned; and is supposed to have 

 been the old standard of a yard, lodged there in the time of King Henry the 

 7th, and used as such, till the other above-mentioned, and now accounted the 

 standard, was made to supply its place. 



Now, as the yard is from very old time mentioned in our acts of parliament, 

 as containing 3 feet, or 36 inches; and the ell is not therein particularly de- 

 scribed, though universally reputed equal to one yard and a quarter, or to 45 

 inches; we shall in the following comparison suppose, that the length of the 

 square brass yard rod, here kept, and marked with a crowned e, by that length 

 meaning, as above, its greatest length between two parallel planes., to be the 

 true and genuine length of the English yard, or of 3 English feet; and with 

 that length we shall compare the others here mentioned, expressing how much 

 they respectively exceed, or fall short of, this supposed standard measure. 



To examine all which, Mr. Graham was provided with very exact and curious 

 beam-compasses of different sorts, and adapted to the several purposes they 



