( 4' 8 ) 
c certain Diftance there j upon which I fitted my 
tc Machine to ftrike to that Diftance, and accordingly 
<c it did fo. We then alter’d the Motion of the boat, 
“ and row’d much fafter to the Mark than we had 
<c done before •, however, the Bell flruck, when we 
Cc came up to it, to the greatefl Exaftnefs: And fuch 
<c is the Property of this Inftrument, that it may be 
“ fitted to ftrike to Miles, Leagues, &c. as fhall be 
“ thought proper. This Machine is made of Materi- 
c * als fo durable, that one of them fhall laft 50 or 60 
“ Years 0 and fuch is the Price, that they will prove 
£( as cheap or cheaper to the Government, than the 
“ Log, which is attended with an Expence of fo ma- 
<c ny Lines, Glalfes, &c . As for the making a Trial 
<£ of this Inftrument, it may be as fully done in the 
“ Channel, as in an Eajl. India Voyage ^ for if it an- 
cc fwers to 20, 30, or 40 Leagues, the Reafon holds 
<c good for as many Thoufand. 
2 d. cc The chief Property of the Log is to have it 
“ fwim upright, or perpendicular to the Plane of the 
ct Horizon. This is too often wanting in Logs , be- 
“ caufe but few Seamen examine whether it is fo or 
“ no, and generally take it uponTruft, being fatis- 
ct fied, if it weigh a little more at the Stern than the 
fiC Head. What erroneous Reckonings Bow from hence 
<£ is but too evident *, for if the Log does not fwim 
Ce upright, it will not hold Water, neither remain 
ct fteady in the Place where it is heav’d, fince the 
cc leaft Check of the Hand, in veering the Line, will 
“ make it come up feveral Feet. This repeated, the 
“ Errors become Fathoms, and perhaps Knots, which, 
tC how infignificant foever they may feem, are Miles 
£C and Parts of Miles, and amount to much in a long 
4£ Voyage. 
In 
