[ 68 S ] 
When I firft ckfigned to have an Inftmment con- 
ftru&ed anfwering to the foregoing Principles of 
Big. i. I drew a Figure of it, wherein I propofed 
the Lever AT) to have terminated in two Arches of 
Circles made out of one Piece of Brafs > the fmaller 
Arch formed on the Radius a A to be loaded with 
a Quantity of Metal fufficlent to overcome all the 
Fridtion of the feveral Parts, fo as to prefs down 
with a confiderable Weight, and always to reft upon 
the Point A of the upright Rod AB j at a the Axis, 
on which they were to turn 5 and the larger Arch 
form'd on the Radius aT), was propofed to be a Sex- 
tant, the outward Edge of which was to be toothed, 
which Teeth were to play into the Teeth of a fmali 
brafs Wheel carrying a ftcel Index like the Minute- 
hand of a Clock, which fmali Wheel with the Hand 
was to make one Revolution nearly by the utmoft 
Rife and Fall of the Sextant at B ; or, inftead of 
Teeth, I propofed a Piece of a Watch-Chain to be 
fatten'd to the upper Limb of the Sextant, and fo to 
be brought downwards, and patting nearly round 
the fmali Wheel in one Groove, to be fallen d to it : 
In another Groove in this fmali Wheel was another 
Piece of Watch-Chain to be fallen d 7 which, being 
palfed contrary wife round the faid Wheel, was to 
have a Weight hung to it that would be a Counter- 
poife to the Sextant 5 bur, upon confulting my two 
ingenious Friends Mr. Geo . Graham and Mr. John 
Ellicot two worthy Members of this Society , they 
each of them perfuaded me to lay afide that more 
complexed Conftrudlion, and to have the Inllrument 
made in the plain and finiple manner in which Mr. 
Jackfon 
