There was a John Sellar of Wick who marked his silver in various ways, he has marked a piece with just JS on its own, but there are several ways he marked items, sometimes with Wick or with Tain (eight in total) but there is a mark of his with JS WICK JS JS.
Also there was a James Stobie of Perth, l have four entries for him, he also had JS twice but an eagle in between.
John Sellar was working between 1825-1835 and his marks have been found on tableforks and spoons
James Stobie 1821-1866 marks on toddy ladle
l am afraid l have no pics
Apologies, I have been very tied up for a couple of months.
Sadly, I cannot help with this one, it is not a mark that I have seen before.
It is not like any JS that I have seen previously, as the 'J' is virtually a reversed 'L', with alonger stroke at the bottom than was used by Sturrock or Sellar or Stobie. It does look like a handmade punch, so it is definitely 'Provincial', but for what country,I have not the faintest idea.
The lack of a drop tells us that it was forged out of one piece of silver.
Richard
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