By Porter Lang
It is raining, again, and you are looking for a coat. Before you buy a “mac”, it helps to know that the word started as a method and not a style. The method was this: take a rubber solution, paint it on one layer of cloth, press a second layer on top, and let it dry.
We read seven sources: the Science Museum Group’s collection record, Encyclopaedia Britannica, the National Records of Scotland, the Linda Hall Library’s science history page, a popular how-things-are-made biography, a retailer-sponsored blog post and Wikipedia. They agree on the outline and disagree on some dates, and we show both.
The chemist
Charles Macintosh was a Glasgow chemist and textile businessman. The National Records of Scotland says he set up the first alum works in Scotland in 1797 and developed new methods for bleaching, printing and dyeing cloth, and for making iron. It says he was elected to the Royal Society for discoveries in chemistry. So he was not a tailor. He was a man who understood waste.
The waste mattered. The Linda Hall Library says naphtha was one of the components of coal tar, a cheap by-product of coal-gas production, and that Macintosh found it was an excellent solvent for rubber. A second source, a how-things-are-made biography, calls it a waste product of the city’s gasworks.
The method
Britannica says that in 1823 he found that coal-tar naphtha dissolved India rubber, and he used the solution as a cement. He painted one side of wool cloth with the rubber preparation and pressed a second layer of wool on top. The Linda Hall Library says the cloth was fully waterproof once dry.
Our reading: the outer layers did the wearing and the rubber in the middle did the keeping-out. The coat was a laminate before the word was common.
The coat was not instantly loved
The Science Museum Group’s record says the waterproofs smelled unpleasant and were not at first popular. Orders from the armed services and stagecoach travellers kept the business going. The retailer-sponsored blog adds that the seams were easy to pierce and that the fabric went stiff in the cold and sticky in the heat. That blog is promotional, and it is the only one of our sources to describe the stiffness and stickiness, so we mark it as a single-source claim.
Dates in order
- 1766: Macintosh is born in Glasgow. The date is disputed; see below.
- 1823: the patent, according to the National Records of Scotland and Britannica’s year for the discovery.
- 1824: a factory is persuaded into being beside a mill in Chorlton-on-Medlock, Manchester, according to the Science Museum Group.
- 1825: the chemist Thomas Hancock improves the process, according to the Science Museum Group.
- 1831: Hancock becomes a partner and the businesses merge, according to the Science Museum Group.
- 1836: “mackintosh” has come to mean any raincoat, according to the Science Museum Group.
- 1839: vulcanised rubber becomes available, according to Britannica. This is a different date from the next entry; see below.
- 1843: Macintosh dies; Hancock is credited by the Science Museum Group with discovering vulcanisation the same year, at about the same time as Charles Goodyear in the United States.
- 1851: the company wins an award at the Great Exhibition, according to the Science Museum Group.
Side by side
Three small disagreements. First, the patent: the National Records of Scotland and the how-things-are-made biography say 1823, the Linda Hall Library says 1824, and Wikipedia credits the invention of the raincoat to 1824 without giving a patent date. Second, his birthday: the National Records of Scotland gives 29 November 1766, while Britannica, Wikipedia and the Linda Hall Library give 29 December. The National Records page also says he was baptised on 10 December, which makes a November birth easier to fit. That is our reading, not the page’s. Third, vulcanisation: Britannica says it was available in 1839 and greatly improved the garment, while the Science Museum Group says Hancock discovered it in 1843. We show all three and choose none.
The spelling
Two of our sources say the origin of the “k” is a mystery. The retailer-sponsored post says it was added later. The Linda Hall Library notes that Macintosh’s own name was spelled without it, while the coat appears with a “k” in a usage the library attributes to Franklin.
What kind of sources these are
The Science Museum Group is a national museum collection. The National Records of Scotland is the national archive. Britannica is a reference work. The Linda Hall Library is an independent science library. The how-things-are-made biography is a popular reference site. The blog post is promotional, written for a coat retailer, and we use it only for the points marked above. Wikipedia can be edited by anyone.
Questions a buyer would ask
What does the label say the coat is made of? A “mac” today may be rubberised cotton or something else entirely; none of our sources says the name is legally protected, and that is our reading, not a finding. Ask whether the seams are sealed or glued, because the history says seams were the weak point. Ask for the care instructions in writing; we give none, as none of our sources does.
What we left out
Prices, factory names still trading, living makers, the later rubber and tyre business, and a Google doodle some sources mention.
Quick answers
Who invented the mackintosh? According to Britannica and the National Records of Scotland, Charles Macintosh, a Glasgow chemist, who patented a rubber-and-naphtha waterproofing method in 1823.
Why did early mackintoshes smell? The Science Museum Group says the waterproofs smelled unpleasant at first, and that this made them unpopular until orders from the armed services and stagecoach travellers kept the business going.
Why is it spelled with a k? Sources do not know. The Linda Hall Library says nobody knows how the name became “Mackintosh” for the coat, though the chemist’s own name had no k.
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Roam first. Shop later.