Graduation of Agronomical InjOrumenU . 35 
1 20 holes from the beginning; you then proceed in the fame 
manner with the other ftrap. 
Method of drilling the Hoop . 
You are now prepared to commence the work upon the 
long or hoop-plate ; and you proceed therewith, in forming the 
firft hole with the chaps, as before dire£ted by Hindley, and 
this firft hole you call o. You then place the ftraps one on 
each fide the hoop, with their gaged edges upward, and put 
the pin through the holes denominated 60 upon the ftraps, 
and through the firft hole already made, and denominated o 
upon the hoop ; then, bringing the gaged edges of the fteel 
plates to be even with the upper or working fide of the hoop, 
you pinch them together in the vife, and drill and broach the 
hole through the fteel plates, which will make the hole, num- 
ber 60, upon the hoop. This done, you put the pin through 
the left-hand hole of the chaps, and the hole marked o upon 
the hoop-plate firft made, and proceed to drill with the chaps 
to 59 holes inclufive, which will fill up the whole fpace from 
o to the 60th divifion before obtained. 
You now again have recourfe to the ftraps, and placing them 
one on each fide the hoop -plate, you put the pin through the 
1 20th hole of the ftraps, and through the hole marked o 
upon the hoop -plate; and regulating the fteel plates to the 
hoop-plate as before, you drill and form a hole with the fteel 
plates, which will correfpond with the 120th hole upon the 
hoop-plate; and afterwards filling up the 59 holes wanting, 
by means of the chaps, you then have all completed to the 
1 20th divifion, which is one-twelfth of the whole circle. 
F 2 
You 
