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."
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.
I WANT TO THANK U FOR YOUR REPLY. IT IS VERY MUCH APPRECIATED AND RIGHT ON.~~D.