Fancy drop cap letter B with draping vines and a formal letter B.
Publishers back in the 1850s relied upon print foundries for fancy letters like theses from Anecdotes for Boys. Entertaining Narratives and Anecdotes Illustrative of Principles of Character. They were sold like movable type and could be inserted into the presses. Gould and Lincoln most likely used the letters in this set in that fashion. The author of the book was Harvey Newcomb.
This image is copyright free and in the public domain anywhere that extends copyrights 70 years after death or at least 120 years after publication when the original illustrator is unknown.