10c Washington single on cover
used; position 52R. The stamp prepaid a single rate for a cover that traveled more than 300 miles, from New York City to the Canadian-U.S. border.
The usual transit mark of a Canadian exchange office is missing, which might lead one to assume the U.S. stamp prepaid the "through" rate to the Canadian address, which was adopted on April 6, 1851. However, that is impossible because of the manuscript "4 ½" rate, being the Canadian postage from the border to Montreal, and the fact that we know the letter was mailed in 1850.