» The USE and DESCRIPTION of a NEW-INVENTED 
‘ INSTRUMENT for SA ON: by which every 
. Na Cafe. in plane: middle Latitude or Mercator’s Sailing may be per- 
| «formed, without Logarithms, Tables, or any numerical Calculations 
hoe: ys “neti COOKE, Yam M.R.L A. 
>. Se 
r 
By 2 
eae © Lis e 
ia HE. bie: 0§; ‘thie Ae acon, is to eee the art ee Read ae 
navigation, | by ' refolving mechanically every problem neceflary “’ Bi 
in failing. 
If is compofed of a val perpendicular, a femicircle, and 
+ an ‘index; which are fo connected by flides, as to be capable of 
being moved into every neceffary pofition. The femicircle con- 
tains the degrees of the circle, and alfo the points of the com- 
ie pais, for the purpofe of laying off the courfe ; the index, per- 
We pendicular and outfide edge of the bafe reprefent the diftance, 
: - departure and proper latitude refpectively ; they are equally 
graduated, and’ each divifion ftands for a mile. There is: alfo 
S another 
