French Catalan mathematician, physicist, astronomer, and politician (1786-1853). ALS in French, signed “F. Arago,” one page, 8 x 10.25, personal letterhead, August 25, 1839. Letter to Giovanni Plana, “Directeur de l’observatoire de Turin.” Writing in the same week he made his famous lecture on Daguerre’s process to the French Chamber of Deputies (Aug 19th 1839) that revealed the daguerreotype secret to the world, Arago recommends a scientist with whom his correspondent may speak of such diverse subjects as transcendental analysis, mechanics, astronomy, physics “without ever fearing not to be understood.” Second integral page bears an address panel in Arago’s hand and wax seal remnants. In fine condition, with intersecting folds, one lightly passing through single letter of signature, a couple circular areas of toning from red wax seal, some light soiling, and small area of paper loss to second page. RRAuction COA.
