I did some more "research" trying to find evidence of old SRs.

In the French Encyclopedia (1762-77), among the more than 3000 plates with
tens of thousands of illustrated items, I can find only one SR-like. It
isn't logarithmic however - only evenly divided scales. It is found under
'astronomy'. None under 'math'.

The famous Samuel Johnson's Dictionary (1756 and 1843) has no mention of
SRs.

The 20 volume edition of the Oxford English Dictionary has the first
literary reference from Samuel Pepys (1663). But that only concerns a 'slide
rule for measuring timber'. The next reference is from 1838, about slide
rules for 'working mechanics'.

I also looked in the 1897 Sears catalog. It only shows a sector-like item
among carpenter's accessories. It is called a 'slide rule' and one leg has a
'Gunter's slide'. (Price 25 cents!) No 'regular' SRs.

With regards,
John Mosand