C A]° ) 
I eftitnoniaJs, forne other Certificates whereby it will 
further appear, that the Marine Surveyor has the Pre- 
ference of the Log , viz. 
“ We the underwritten Matters of Ships, &c, do 
“ certify ail whom it may concern, That this 2 iff of 
‘ Oftober 1725, we accompanied Mr. henry de Sat * - 
<c marez, On board the Richard Yatch, in order to 
u make an Experiment of an Jnftrument invented by 
“ him, call’d the Marine -Surveyor ; and as by it he 
c ‘ propos’d to afeertain the Way of a Ship in the Sea, 
“ much more corredtly than by any Thing hitherto 
“ invented for that Purpofe, we tried it between Lon- 
<c don and Gravefend with the Log (which we hove 
“ feveral Times) to which it appears to us to have 
“ the Preference^ for by its conttant and regular Mo- 
“ tion, the Ship’s Diftance fail’d mutt be more exadly 
“ attain’d than by the Log\ which being hove but 
“ once in an Hour or two, cannot be fo corred, in 
“ regard the Wind may increafe or letten foon af- 
“ ter the Log is hove, in fuch Manner, that it entire- 
“ ly depends on him who chalks the Log-board to 
“ allow for it. As therefore very confiderable Errors 
■ u muff arife from thence, if a proper Allowance is 
c ‘ not made for an Increafe and Decreafe of Wind \ and 
“ as the Marine-Surveyor is not fubjecl to this, but 
“ keeps a regular Motion, according as the Wind is 
“ more or lefs : We are therefore of Opinion, that 
<c this new Invention is not only an ingenious Con- 
“ trivance in its Kind, but is exactly calculated for 
u the Ends propofed. As witnefs our Hands this 21ft 
“ of O Bober 1715. 
J Michael Hales , 
Benjamin Hut chin f bn , 
Jojiah Hales , 
Peter Perchard, 
Robert Gamble. “ Thefe 
