This plate is identical to one that appeared in the Magazine Antiques in March 1986.  According to the article, similar plates were owned by a well-established merchant and justice in York, Maine, named Jonathan Sayward (1713-1797).  The plates were purchased in 1760 by Sayward's son-in-law, Nathaniel Barrell (1732-1831), during the course of Barrell's three year hiatus in England.  While the above set of plates appears to have a more pronounced black outline around the water buffalo and surrounding foliage, the plate on display here is identical in design and coloration to those in Maine.   Although it may be impossible to verify, the Hammond-Harwood House plate may have also come from York Harbor, Maine.  Indeed, the original donor had a summer house in the same vicinity and, reportedly, collected a number of objects from York antiques dealers.   Both plates are exquisite examples of the Chinese sensitivity to animal and plant forms.