[ 70 ] 
I to 9. But I multiplied by 10 produces 10, and 
9 multiplied by 10 produces 90, And lo on for all 
the intermediate units. 
X. A Reco7?tmendation of Hadley’s Quadrant 
for furveymg^ efpectally the furveymg of 
Harbours^ together with a particular Ap- 
plication of it m fome Cafes of Pilotage, 
Py the Rev. John Michel), B. D. F. R. S. 
Read Feb. 14, T 
1765. 
H E ufe of Hadley’s quadrant, as 
' an inftrument to take altitudes at 
fea, is already fo well eftablifhed, that it wants no 
farther recommendation but there are feveral other 
purpofes, to which it may be applied, with great 
advantage, which, though obvious enough, feem 
yet to be hardly fufficiently attended to. There is 
no inftrument fo well adapted to many kinds of fur- 
veying, cither for exadnefs or conveniency, and par- 
ticularly the laft; but the furvcying of harbours, or 
fuch fands, as lie v/ithin fight of land, may often- 
times be performed by it, not only with vaflly more 
eafe, but alfo with a much greater degree of preci- 
fion, than can be hoped for by any other means, as 
it is the only inlfrument in ufe, in which neither the 
exadnefs of the obfervations, nor the eafe with 
which they may be taken, are fenfibly affeded by the 
motion of a veffel : and hence a fingle obferver, in a 
boat, may generally determine thefituation of anyplace 
he 
