4>o8 An Account of the Measurement 
into degrees, and every degree into five minutes ; and the holes 
were afterwards opened with a tool made for the purpose. As gold 
pins had been let into the arch, Mr. Berge was enabled to go 
through the division of it with great success, and afterwards to 
enlarge the holes, without destroying his accurate work. The 
observations will offer a more satisfactory testimony of the credit 
due to his abilities as a workman, than any opinion which I 
might express myself as entertaining, although founded on 
the same data. It remains for me only to observe, that I think 
he has delivered this instrument into my hands without any 
imperfection of execution ; and that I believe it would not have 
been superior, had the ingenious inventor lived to complete it. 
Adjustment of the meridional and horizontal Wires. 
After the arch was divided, the axis of the telescope was laid 
on a pair of Ys connected to a firm support, and made nearly 
horizontal. The tube was then brought up to a level with the 
axis, and sustained at proper intervals, whilst the end of the 
telescope rested on a small piece of metal connected to a fixed 
bar, by means of an adjusting-screw. This end was then moved, 
till an object sufficiently small, (a speck or dot,) at a proper 
distance, appeared nearly in the centre of the field. The tele- 
scope was then properly secured from bending, and rendered 
perfectly steady, but admitting of a small motion sideways, the 
Ys having also a corresponding adjustment. 
A microscope, furnished with a moveable wire, was then 
fastened to a beam attached to the brick wall, and its end 
brought close to the edge of the arch of the telescope. Upon 
this edge, as well as on that of the other arch, Mr. Berge had 
the address to lay off a point, very nearly in that place where the 
