404 Major-General Roy’s Account of the 
cond pin. The 'beam being then removed, and one point 
: placed in the interfeclion of the arc and wire, with the other 
: point a dot was made on the third pin, under the middle of 
1 the wire. Upon this dot, as a center, a faint arc was next 
* defcribed on the fame pin where the firft had been traced. In 
this manner the fix times <forty inches were marked off, alter- 
nately with dots and arcs:; a method found by Mr. Ramsden, 
in his practice, .to be more accurate, than when dots only are 
made ufe of. 
The exadt length of twenty feet, thus obtained, was next 
taken between the points of the long beam-compafles, and, 
transferred to the tops of the bell-metal cocks, placed, as has 
been already mentioned, on the tide of the ftandard rod, in 
fuch manner as to leave more than one inch and a half of the 
faid cocks beyond or without the lines denoting the extent of 
the twenty feet. This being done, the meafuring rods were 
fuccefiively placed on the ftandard, and their fides applying 
dole to the cocks, the diftance of twenty feet was readily 
transferred from them to the inlaid ivory pieces, on which fine 
lines were afterwards cut, by marks accurately made for that 
purpofe. 
With regard to the adjuftment of the lips of the bell-metal 
tippings, which extend exa&ly one inch and a half beyond the 
• ivory lines, fo as to make the total length of the rod 243 
inches, it is to be obferved, that they terminate in flat curves 
of 3I inches radius, pafling through the inch and half points, 
to which they were cautioufly ground down, that at firft they 
might rather exceed than be defe&ive in length. Any two 
of the rods, lying in the fame plane, and alfo in the fame 
ftraight line, being brought into contact with each other ; if 
of 
