William Thomson worked in New York City during 1809-45. His two documented marks are W. Thomsom in script. I would suggest contacting curators at New York museums to see if they have examples in their collection.
Following is from Ensko, "American Silversmiths ...":
"William Thomson New York, at 399 Broadway; William Street, 1811 - 1825. Commissioned to make silver service by the City for Captain Samuel Reid for gallant bravery at the battle of Fayal. In directory until 1845."
The following is from: http://www.electricscotland.com/history/world/reid.htm
"Capt. Reid received many honors and was a popular naval hero. The Thanks of Congress and the Medal of Honor were awarded to him along with a gold sword from the State of New York and a silver tea service from the City of New York. The sword is in the Metropolitan Museum and the tea service is in the Museum of the City of New York."
Re: Re: Re: W. Thomson :early american silversmith
I want to Thank u for an insightful adventure into history. I would like to be able to see his work that is in the NYC Museum. Do u happen to know what the tea service looked liked that he made for Capt.Ried. I would enjoy to see some of his tea sets. Do u know if Thomson was Scottish, Welch, or English? I always love the Scot's humor pg. Thanks for a wonderful precise page into Capt. Ried's life.