11,752 of 1854, for an "Improved Pen and Pencil Case". Both Lownds and Wilmarth were active in New York City in the 1850s.
Commodore Stephen Champlin (US Navy records up through 1882 list no other S. Champlin who served as an officer). Born in Rhode Island in 1789, Champlin was a first cousin of Oliver Hazard Perry, and commanded the Scorpion at the Battle of Lake Erie in 1813. Champlin was reportedly the last survivor of that battle, living until 1870, though his career was cut short by crippling injuries suffered in an engagement in 1814.
US Navy ships have been named after Stephen Champlin, as has the town of Champlin, Minnesota.
UPDATE: This very pen-pencil appears to have been mentioned in Champlin's will, signed December 17, 1869, bequeathed to a grandson:
"Item Fourth: I give, devise and bequeath, to my daughter, Eliza Ellen Cook, mine and my wife's portraits and frames for same, writing desk formerly used by my wife, gold pen and holder, picture and key, entitled Union, with frames, photographic album containing fifty pictures, and eighteen numbers of Shakespeare's pictures; and to her son, Stephen Champlin, my gold pencil case and pen."Other gold pens are mentioned, but no other pencils or pencil cases, as mechanical pencils were then called.
Maiden Lane was the center of the Manhattan jewelry trade throughout the 19th century, including pen manufacture.