XIX. An Account of fome Improvements of 
the Mariners Compafs, in order -to render 
the Card and Needle, propofed hy DoBor 
Knight, of general Ufe , by John Smeaton, 
Philofophical lnflrument -maker. ■' 
Cover of , the \? odcn 
Box being taken oft, the 
ations. 
Compafs is in a Condition to be made ufe of 
in the Bittacle, when the Weather is moderate : 
But it the Sea' runs high, as the inner Box is hung 
very free upon its Centres (the better to arifwer its 
other Purpofcs) it will be neccftarv to flacken' the 
mill’d Nut, placed' ftpon one of the Axes that fup- 
ports the Ring, and to tighten the Nut on the Out- 
fide that correfponds to it. Bv this men'fts the inner 
Box and Ring will' be lifted' up from the Edges, 
upon which they reft, when free; and the Friftion 
will be increafed, and that to any Degree nccefiary 
to prevent the too great Vibrations; which o her- 
wife would be occafioncd by the Motion of the 
Ship. : 
To make the Compafs ufeful in taking the mag- 
netic Azimuth, or Amplitude of the Sun and Stars, 
as alfo the Bearings of Head lands, Ships, and other 
Objects at a Diftance,' the -brats 'Ed ip*, defigned at 
fit ft to fupport the Card, and throw the Weight 
thereof as near the Circumference as poftible, is 
itfclf divided into Degrees and Halves 5 wnich may 
be cafily eftimated into imaller Parts, if nccefiary. 
The 
