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Here's what I found.
William Jackson & Co., Sheaf Island Works - Pond Hill, Sheffield, UK

Apparently the name predates 1852 as Ashton died in 1846 and Jackson changed the name in 1852.

That's the generally accepted answer. Others say 1892 because of the McKinley Tariff Act of 1891 which among other things stated that all items imported into the US had to be marked with their...