Raincoats are often called "macs", invented in the year 1823, it came from the Surname of Charles Macintosh. He made a cloth waterproof by sandwidhing a layer of rubber between two lengths of a cotton.
Back then, when it get wet it weighed a ton and smell awful. Todays raincoats are made of waterproof fabrics like Gore-Tex and coated nylons. These fabrics allow some air to pass through, allowing the garment to 'breathe' so that sweat vapour can escape.
