Charles Macintosh is born in Glasgow, Scotland. He will be remembered as the inventor of rubberized waterproof clothing, especially the raincoat that bears his name.
Son of a dye maker, Macintosh developed an early interest in chemistry and science. By age twenty he was already running a plant producing ammonium chloride and Prussian blue dye, introducing new techniques for dyeing cloth. In partnership with Charles Tennant, Macintosh developed a dry bleaching powder that proved popular, making a fortune for both men. The powder remained the primary agent for bleaching cloth and paper until the 1920s.
Macintosh began experimenting with waterproofing fabric, using waste by-products from the dye process. That included coal tar, which could be distilled into naphtha. By joining two sheets of fabric with dissolved India rubber soaked in naphtha, he made the first truly waterproof fabric that was supple enough for clothing. He patented it in 1823.
When the waterproof fabric was made into a raincoat, the garment quickly became known as the mackintosh. (The k comes from the spelling preferred by the chief of clan Mackintosh.) The coat came into widespread use by the British army and the general public. The fabric got stiff when cold, and sticky when warm. And wool’s natural oils caused the rubber cement to deteriorate. But the process was improved over time and was effective enough to be used for one of Sir John Franklin’s Arctic expeditions.
But Macintosh was no one-trick pony. Besides developing rubberized fabric and bleaching powder, he also helped devise a hot-blast process for producing high-quality cast iron.—TL