British economist and entomologist (1783–1860). ALS signed “W. Spence,” one page, 4.5 x 6, no date. Letter to Jno. Bradley. In part: “I will with pleasure accept Harris which will be very valuable to me on condition that you however do Caulder in his duo decimo cup with a place in your superb collection.” Letter is inlaid to a slightly larger off-white sheet. Scattered toning and a couple small pencil notations, otherwise fine condition. RR Auction COA.