260 AN ACCOUNT OF THE 
stretched by 28 Ibs. Supposing what is most probable, that the length of 
the chain was adjusted from the standard brass scale, when at the same 
temper ature of 55, » We? get its length in 62 = 100 feet 01987 x T= 
100 — 037 = 1199-913, and the distance of the registers consequently 
1199-96 inches, that is supposing the chain stretched by a weight of 19 Ibs. 
Inches. 
But the rods it has been seen exceed the registers by °054. Their length 
inches. 
will therefore be 1200-014. Comparator being 1093. ‘This operation was - 
performed before commencing the measurement. 
42, Tur second comparison was made on the 8th February, The 
register heads had remained fixed inthe same ‘position in .which the former 
comparison had been made, although there was no reason for suspecting 
any derangement, yet it was thought proper to verify them, and by a mean 
of several comparisons, their distance was found, the chain being reduced 
to 55, and stretched by weights of, 14 lbs. 28 Ibs. 
1200°072  1200:036 
Tue rods were then substituted between the registers over the zero 
lines, of which silk threads were stretched at right angles, to the axis of 
Inches, - 
the rods, and the rods were found to be less than the registers, 174, 
1.2—2.3 3.4—4.5 
Now the Nonti were,.... 0°703 & 0:303 
Zero GivisloNs,.s-cevsseae L°3OO 0-237 
Inches. Inches. 
—°597 = -149 — 0°066* == -036 
Inches. 
The sum of these 18,...ce.cce+ee 180 
Soe 
* Tue divisions of this Nonius were as was before remarked, réckoned im a reverse order. 
