The maker's mark "WS" is very difficult to attribute as there were so many makers with these initials operating at this time. I have attributed these tongs to William Stroud as being the most likely maker. This is a guess - at best. William Stroud entered his first mark on 7th July 1788 as a plate-worker. William Stroud had been apprenticed to John Wirgman who we know made sugar tongs. His second mark was not entered until 9th March 1821, some 33 years later. An interesting observation about this maker is that his maker's marks are very often struck twice. Two examples are shown below.
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Two examples of maker's marks struck twice