Hogsheads and casks of tobacco were branded with the symbols or initials
of the original owners. Many of the brands are recorded explicitly in
the ledger. Mercer, at the beginning of his career, used a symbol M. As
his plantations multiplied, however, three symbols were adopted, based
on his own two initials. Tobacco casks from Bull Run were marked
I^[B.]M. Those from Sumner's Quarters bore the brand I^[S.]M, while the
"Home Plantation" at Marlborough had casks marked I^[C.]M (fig. 8).
The interpretation of these symbols warrants some digression. In the
17th century, and indeed in the 18th century also, the triangular cipher
to indicate the initials of man and wife was commonly used to mark
silver, pewter, china, delftware, linens, and other objects needing
owners' identifications. The common surname initial was placed at the
top, the husband's first-name initial at the lower left, and the wife's
at the lower right. This arrangement was used consistently in the 17th
century. In the 18th century, however, variations began to appear in the
colonies, although not, apparently, in England. Silver made in New York
and Philadelphia during the 1700's presents the initials reading from
left to right, with the husband's at the lower left, the wife's at top
center, and the surname initial at the lower right. The large keystone
of the Carlyle house in Alexandria, built in 1751, bears a triangular
arrangement of John and Sarah Carlyle's initials: J^[S.]C.[88]
Like Carlyle, Mercer used initials in this fashion, but also, as we have
seen, in two other combinations in which "J. M." remains constant, the
upper center initial having a subordinate significance. "S" signifies
Sumner's Quarters, and "B," Bull Run Quarters. "C" on seals and brands
having to do with Marlborough apparently refers to Catherine, honoring
her as Mercer's wife and mistress of the home plantation. The
possibility that "C" stands for Cave's warehouse may be dismissed as
being inconsistent with the other two marks, the tobacco from Sumner's
Quarters having also been shipped through Cave's, and that from Bull Run
Quarters having been stored at the Occaquan warehouse.[89]
John Withers also used the left-to-right arrangement, I^[H.]W, although
Henry Tyler, a planter whose account is mentioned in Mercer's Ledger,
used the conventional three-letter cipher, H^[T.]M. These marks occurred
on casks transmitted to Mercer as payments, and are recorded in Ledger G
(fig. 7).