Perhaps clear up this...Does it read Mount (MT.) Washington House or My Washington House...a big difference as Longfellow's House in Boston is where Washington once lived and Mount Washington could refer to some other structures. And the dating could bear on the maker or retailer marks....for instance Henry Guild (using full name mark) was a Boston manufacturing jeweler in the middle decades of the 19th century. Some of these guys might have alternate marks as maker or retailer.