(SCIENTISTS.) BIOT, JEAN-BAPTISTE. Two Autograph Letters Signed, "J.B. Biot" or "Biot," to François Arago or "My very dear friend," in French. The first, requesting that no announcement be made about any "drawings colored by atmospheric radiation" [photographic prints] brought to the Academy darkroom unless his own name is associated with them, because there are other very different processes that could produce apparently similar results. The second, sending notes on capillary action and refraction. Together 4 pages, 4to or 8vo, second written on folded sheet; faint staining at lower edge of first, folds. Paris, 24 March 1839; Np, nd
