Charles Macintosh was born in Glasgow on December 29, 1766.
Waterproof material was invented by Charles Macintosh after conducting experiments with the waste products of Glasgow’s new gas works, opened in 1818. It was the forebear of the now more familiar plastic mac.
His father owned a Glasgow factory producing cudbear, a purple dye obtained from various lichens capable of colouring wool and silk.
After studying at local schools, Charles attended the chemical lectures of Joseph Black at Glasgow University. In 1786 he opened his own chemical works – making sal ammoniac and Prussian blue dye – and the first Scottish alum works in 1797.
On his father’s death, Charles Macintosh inherited the cudbear factory and began experiments with coal-tar naptha, a by-product of distilling tar. The coal-tar naptha dissolved india rubber which Macintosh used to form thin sheets of rubber. One sheet was placed over a piece of woollen cloth which was then bonded onto another, forming a rubber sandwich.
The first waterproof cloth was patented in 1823, but was not without problems. The rubber cement was affected by the natural oils in woollen cloth causing it to crumble in cold weather, and when seaming, tailors punctured the fabric allowing rain to penetrate. Macintosh had the early waterproof garments made in a Manchester factory but they were not comfortable to wear.
They became stiff in winter and it was not until much later in the 1970’s that the wearing of sticky, stuffy, sweaty waterproofing in summer was overcome. However the new material became a replacement for earlier methods of waterproofing such as coating ordinary cloth in either linseed oil or tar.
These problems were overcome by the work of Goodyear (the tyre man) and others who patented methods of vulcanising rubber making it stable.
This was followed by other methods of making cloth water repellent by chemical treatment.
Although Charles Macintosh will be remembered chiefly for the waterproof raincoat he had many other interests and contributed greatly to local industrial innovation. In 1799 he worked with Charles Tennant and together they opened a bleach factory at St Rollox in Glasgow.
Here they produced a solid bleaching agent that was used industrially to bleach cloth and paper well into the 1920’s. Charles Macintosh also helped James Beaumont Neilson perfect the hot blast process of smelting iron.
PVC and the rise of plastics
Then came the revolution in plastics which saw first PVC used as sheeting such as in transparent capes or given a colouring to let loose the imagination of art students. PVC was used as a covering for woven cloth but was supplanted by polyurethane which is now widely used as a coating for proofed fabrics.
The 1970’s also saw the next development in plastics, microcellular plastic that allowed water vapour to pass through the microscopic holes without letting liquid through.
The development of waterproofing has had its less glamorous moments. During the 1950s and 1960s no day excursion would be complete without the flimsy, many shades of grey Pacamac. It was capable of being folded down to a square shape that fitted into a jacket pocket, ready to be unfurled once it started to rain.
It was just as swiftly removed and hastily refolded into a less regular shape once the dark clouds had passed. Although as a utility it had no paramour, as a fashion statement it lacked in modern parlance, street cred.
However Charles Macintosh who died just outside of Glasgow on July 25, 1843 can rest assured that his name, like that of Sandwich and Biro has entered the vocabulary as an item of everyday use.
© John Barber – originally published in the Glasgow Herald 9 April 1998
This page and more in a similar vein comes from a collection in my eBook. An echo from the Green Fields .