Silver medal, 51 mm by H.Stokes, impressed around edge 'Charles Macintosh & Co., Manchester - Indiarubber Goods. In original satin-lined box). 92gr. Charles Macintosh Frs (1766, 1843) was a Scottish chemist and the inventor of waterproof fabric. The Mackintosh raincoat (the variant spelling is now standard) is named after him.