8 A Catalogue of 
hermetically inclofed within a glafs tube for 
the pocket. 
39 Air levels, with telefcope lights, mounted on 
a three-legg’d ftaff; they have a particular 
contrivance, by which they may be adjufted 
(if put out of order) to a true level at any 
one ftation. 
40 Gunners levels, generally called perpendicu* 
lars. 
41 Levelling Haves 
42 Plotting fcales, 
43 Feather edged fcales. 
44 Pantographers, for reducing, or enlarging, or 
copying plans of furveys, pictures of any 
kind, and reducing fhadows of the human 
lide face, and this without any previous ha^ 
bit of drawing. 
45 Pedometers to meafure the way in walking. 
46 Perambulators, way-wifers, or meafuring- 
wheels, ditto for coaches. 
47 Major General Williamfon’s new inftrument 
for elevating pieces of ordnance. 
Optical Inflruments* 
Effecting tellefcopes, 12 inches. 5 
Ditto 18 inches. 8 
Ditto 2 feet. —• 12 
Ditto on a rack Hand. 21 
Achromatic profpedts for the pocket. 1 
Achromatic tellefcopes, either in nurfe 
Hein for the pocket, or mahogany 
tubes, 2 feet. — 2 
54 Ditto 3 feet. -—- 3 
54 Ditto 4 feet. 4 
49 
50 
5 2 
53 
CL O 
8 o 
12 o 
o o 
1 6 o 
2 o 
3 0 
4 o 
And 
