Autograph Letter Signed, to Mr. C.St.Barbe, recommending “a Young French Captain [Courtois St Clair] who is cast upon your Town [Lymington] by an extraordinary adventure”, and sending [here present] a printed pamphlet [8 pp.] containing letters by Kelly, entitled ‘Facts relating to The Nautical Almanac and Connoissance des Tems’ (1812). 3 pp. 9 x 7½ inches, folds, in good condition. Finsbury Square, 10 January 1812. Patrick Kelly (1756-1842), mathematician, astronomer and metrologist, best known for his comparative studies of weights and measures collected in his works Universal Cambist (1811) and Oriental Metrology; comprising the monies, weights, and measures of the East Indies, and other trading places in Asia, reduced to the English standard. … To which is added an Appendix on Oriental measures of time (London, 1832). He was also instrumental in the establishment of the Imperial system of measurement through the Weights and Measures Act 1824. He was for many years master of a successful private school called the Mercantile School in Finsbury Square.