Charles Lamb, Letters
(November 25, 1819, to Dorothy Wordsworth):
It is hard to discern the oak in the acorn, or a temple like St. Paul's in the first stone which is laid; nor can I quite prefigure what destination the genius of William Minor hath to take. Some few hints I have set down, to guide my future observations. He hath the power of calculation in no ordinary degree for a chit. He combineth figures, after the first boggle, rapidly; as in the tricktrack board, where the hits are figured, at first he did not perceive that 15 and 7 made 22; but by a little use he could combine 8 with 25, and 33 again with 16,--which approacheth something in kind (far let me be from flattering him by saying in degree) to that of the famous American boy.
The notes in my Everyman's Library edition of Lamb's letters do not identify the famous American boy. My guess is that he was Zerah Colburn
. On Colburn see Martin Gardner, Mathematical Carnival
(New York: Vintage Books, 1977), pp. 67-68.