( ij6 ) 
the Hand without any {landing Support. In this 
Manner the Altitude of the Sun, Moon, or fome of 
the brighter Stars from the vilible Horizon may be 
taken at Sea, when it is not too rough. 
F i g. IV. {hews an fnftrumeht defigned for this 
Purpofe ; differing from the foregoing Defcription 
chiefly in the placing the Specula and Tele {cope,, 
with regard to the Sedtor and Index ; it has alfo a 
third Speculum N O difpos’d according to the Direc- 
tions when the Angle is greater than 90 Deg. whofe 
Ule is' to obferve the Sun’s Altitude by Means of the 
oppofite Part of the Horizon. In placing thefe two 
fmaller Specula, it will be farther neceflary to take 
care that the Speculum IKGH do not ftand fo as to 
intercept any of the Rays coming from the greater 
one fix’d on the Index to the third N O, nor either 
of them hinder the Index from coming Home to the- 
End of the divided Arch. WQ. is a Director for the 
Sight-, which is neceflary when the Telefcope is not 
made ufe of. This confifts of a long narrow Piece, 
which Aides on another fix’d on the back of the Oc- 
tant, and carries at each End a Sight erected perpen- 
dicularly on it: It may be removed at Pleafure, and 
exchanged for the Telefcope, which Aides on in the 
fame manner, both ferving indifferently with either 
of the two fmaller Specula. The Eye is to be plac’d 
clofe behind the Sight at W ; and the Thread ftretch’d 
acrofs the opening of the other Sight at Q. perpendicu- 
lar to the Inftrument is to aflifttheObferver in holding 
it in a vertical Torture, who is to keep this Thread as 
near as he can parallel to the Horizon, and the Objeft 
near the upright one. How far an Inftrument of this 
Kind 
