to ascertain a Standard of Weight and Measure. 171 
and found it to agree exactly with that of 1758 ; at least it did 
not differ from it more than ,0002 inch*. 
(§• 39-) I was now to examine the old standards kept in 
the Exchequer: these Mr. Charles Ellis, Deputy Chamber- 
lain of the Tally Court at the receipt of the Exchequer, was so 
good as to supply me with ; viz. the standard yard of the 30th 
of Eliz. 1588, and also the standard ell of the same date. 
These are what have been constantly used, and are indeed the 
only ones now in use, for sizing measures of length -f. They 
are made of brass, about 0,6 inch square, and are very rudely 
divided indeed, into halves, quarters, eighths, and sixteenths ; 
the lines being two or three hundredths of an inch broad, and 
not all of them drawn square, or at right angles to the sides of 
the bar, so that no accuracy could possibly be expected from 
such measures. However, the middle point of these transverse 
lines, between the sides of the bar, was taken as the intended 
original division ; and these divisions, such as they were, were 
transferred, by a dividing knife, to the reverse side of my 
brass scale made by Mr. Troughton, the thermometer be- 
ing at 63°; and, at my leisure afterwards, I found as follows. 
The ends of these venerable standards having been bruised 
a little, or rounded, in the course of so many years’ usage, I 
conceived a tangent to be drawn to the most prominent part, 
which was about the centre or axis of the bar, and this point 
* These quantities then being so small, I shall consider them as wholly insensible; 
and shall say, that Mr. Bird’s parliamentary standards of 3 feet exactly correspond 
with Mr. Trough ton’s scale. 
f There was also a standard yard of Henry VII. but of very rude workmanship 
indeed ; now quite laid by, and at what time last used, no information remains : but 
of this more hereafter. 
Z2 
