[ >55 ] 
I. j 4 true Copy of a ‘Paper found, in the Hand 
Writing of Sir Ifaac Newton, among the 
1 Papers oj the late *Dr. Halley, containing a 
‘Defcription of an Inftrument for obfer^ing 
the Moon's Diftance from the Fixt Stars at 
Sea. 
Read at a. -y the annexed Scheme, BQRS de- 
Royal society, 1 notes a Plate of Brals, accurately di- 
Ociober 18. vided in the Limb ‘DQ, into- De- 
17+2 * grees, ~ Minutes, and Minutes, 
by a Diagonal Scale,* and the \ Degrees, and \ Mi- 
nutes, and ~ Minutes, counted for Degrees, Minutes, 
four Feet long, 
and £ Minutes. 
AB , is a Telefcope, three or 
fixt on the Edge of that Brafs Plate. 
G , is a Speculum , fixt on the faid Brafs Plate per- 
pendicularly, as near as may be to the Objeft-glafs of 
the Telefcope, fo as to be inclined 45 Degrees to the 
Axis of the Telefcope, and intercept half the Light 
which would otherwife come through the Telefcope 
to the Eye. 
C T), is a moveable Index, turning about the Centre 
C, and, with its fiducial Edge, fhewing the Degrees, 
Minutes, and £ Minutes, on the Limb of the Brafs 
Plate ‘P'Qj the Centre C, mull be over-againft the 
Middle of the Speculum G. 
H , is another Speculum , parallel to the former, 
when the fiducial Edge of the Index falls on ood oo / 
oo ,v $ fo that the fame Star may then appear through 
X the 
