Graduation of Afronomlcal Infir uments. 39 
their entry, into which fmooth taper pins are to be driven ; not 
with violence, but moderately, that no fenfible firetching of 
the folid parts may take place thereby ; then cutting off and 
fmoothing the heads, fhift the vifes fo as to receive another 
couple of holes, and a third couple in the fame end of the hoop ; 
and proceed progreffively in the fame manner, from the middle 
to the other end of the rivet plate ; then gently feparate the in- 
ternal brafs mould with a thin knife, or fuch like inftrument ; 
and cutting off, and very lightly ri vetting the inner ends, pro- 
ceed to fix the other rivet plate, in the fame manner, on the 
other fide : by this means the hoop will be firmly joined in the 
very pofition given it by the faddle plates and mould. Thefe 
plates may then be removed, the infide of the hoop cleared and 
fmoothed, if neceffary ; and the outfide will have the middle 
part clear where the divifions lie, and that without fenfible lofe 
or gain in the juncture* 
Method of transferring the Divifions of the Hoop to a dividing Plate . v 
The hoop being thus refitted for the chock, that fhould be 
turned down to leave a fhoulder on one fide, that the hoop, now 
reduced to an equal breadth, may be forced againft it ; and the 
divifions, being equally diflant from one of its edges, will be 
all found in a circle, as if turned upon it. It fhould be very 
carefully fitted to the chock, that it may go on with a fufficient 
degree of tightnefs, and without the neceffity of much forcings 
and it will be no inconvenience now, if it goes on upon a very 
flight degree of taper of the chock, as the internal fpring of the 
materials will eafily accommodate it to this fhape without any 
injury to its general truth : a flight degree of a groove fhould 
