f 45 1 ) 
confequently be of very great Advantage to Naviga- 
tion. The Method ufually pradtifed, is by taking 
the Sun or Stars Meridian Altitude or Zenith Di- 
ftance : In this Cafe, if the Sun does not fhine but 
for fome fmall Time only, before Noon and after, 
though it be clear all the reft of the Day, it is of 
no ule for this purpofe. Mr. Fatio, F.R.S, (in the 
Year 1718) propofed a Method for finding the La- 
titude, from two or more Obfervations of the Sun 
(or Stars) at any Time, the Diftance of the faid 
Obfervations in Time, being given by a Watch ; 
but as his Method requires a vaft Number of Com- 
putations, and a great deal of Skill in Spherical Tri- 
gonometry, it has very feldom been made ufe of, 
and never but by good Mathematicians. The fn- 
ftrument here defcribed will anfwer the fame End, 
and has thefe Advantages ; viz. 
1 J{, It may be very eafily underftood by Seamen! 
idly-, It immediately Ihews the Latitude of the 
Place. 
3 dly, It gives the Time of Day at Sea when no 
other Inftrument can. 
4 thly. It may be made as large, and confequently 
as accurate as is defired. 
A Defer ip ion of the Inftrument. See Fig. z. 
ABC reprefents part of the Hemifphere of a large 
Globe (half the Globe, and the Part below the Tro- 
pick are cut off, that it may take up the lefs room.) 
AC, half the Equator, divided into 12 Hours above, 
and 180 Degrees below, and fubdiyided into Minutes, 
O 0 0 2. as 
