■( JO.,;,. 
learned Gentlemen afore* mentioned, which is plainly 
made appear from the following Figure, wherein the 
Pofition of the Fork, in live different Motions of the 
Veffel, is reprefented. See Fig. 3, 
This needs no Explanation, for it plainly appears, 
that the Pallets will be more or lefs affefted by the 
Refinance of the Water, according to the Pofition 
they are in j and therefore the Revolutions in a fwift 
or flow Motion, in the fame Diftance, cannot be 
equal. 
Being now fully perfuaded, that the Fork would 
not revolve equally in the fame Diftance, and in dif- 
ferent Motions of the Veffel, I now began to repair 
this Defed by calculating fome Tables, which render 
it ftill a very ufeful Inftrument. On what Founda- 
tion I formed thefe Tables, there will be no need for 
me to mention, lince I ftiall go on to fliew what fur- 
ther Improvements I have made of this Inftrument, 
and that it is now every Way ufeful without them. 
And this, I think, I cannot better do, than by en- 
tering here the Extraft of a Letter to Dr. Defa- 
guUers from a learned Mathematician in Holland^ 
whofe Company I was honoured with feveral Times, 
whilft I was making my Experiments on that Side, 
viz, 
‘‘ Mr.Z>^ Saumarez having defired me to acquaint 
you of the Succefs of the Experiments, which I 
have feen him make of this Machine, for the meafu- 
“ ring the Way of a Ship in the Sea, it is with Pleafure 
“ I undertake it, fincc I am fully perfuaded you 
“ will not be wanting to contribute all in your Power 
“ to promote an Invention fo ufeful and advantage* 
" ous as this is. 
“ The 
