|Pass #17236 George Underhill, Shropshire, butcher|
The passes begin at Image 33 with number 17228. To find an ancestor pass, just find the name in the list at Immigrants proceeding to Upper Canada via New York 1817-1819 , copy the pass number then go to Canadiana.org and paste the pass number into the search engine that says "Search within this reel"
For example one name on the list is
17236 George Underhill, Shropshire, butcher, wife + 4 ch
If this were your ancestor you would use the Canadiana.org link above and enter 17266 into the search engine on that site. You can see his pass above.
[Source: Upper Canada Sundries, Reference: RG 5 A1, Volume 37, passes numbered 17228-17578, microfilm: C-4601. Civil Secretary's Correspondence - Passes signed by British Consul, New York, for Emigrants from Great Britain, 1817-1819. Microfilm available at Canadiana.org but it is not indexed]