American astronomer and mathematician (1809-1880), remembered for his accurate computation of the perturbations of Uranus and Neptune, for his studies of the rings of Saturn, and for his papers on a new mathematical field, Linear Associative Algebra. ALS signed “B. Peirce,” one page both sides, 5.25 x 8, March 23, 1862. Letter to his sister. In part: “I suppose you expected to have heard from Lucy yesterday but I forgot to write…I went out to have some photographs taken yesterday.” In fine condition, with intersecting folds one through a single letter of signature, a bit of scattered light toning, and a trimmed left edge. RRAuction COA.