In the US, 'crapper' means lavatory; one theory is that the word was brought back by American troops serving in Britain during the First World War who were impressed by Thomas Crapper's products. But if the word 'crap' was used to mean defecate as far back as 1846, Thomas Crapper cannot have been responsible, since he was only ten years old at the time.
Thomas Crapper was a successful London plumber who was employed by the royal family when they refurbished Sandringham House in the 1880s. He may also have invented the siphonic flush---but that is most unlikely. He certainly did not invent the water-closet.
Crapper was born in 1836---the year before Victoria came to the throne---in the little town of Thorne, near Doncaster in Yorkshire, England. Thorne was then a thriving port; barges came up the River Don and unloaded cargo on the docks. Thomas' dad was a sailor, and his brothers were dockers, but he must have been unhappy at home, for at the age of eleven, according to Reyburn, he walked 165 miles to London and got himself apprenticed to a plumber in Chelsea. By 1861 he had his own business, which became Thos Crapper & Co, Marlborough Works, Chelsea, and survived until 1966. Thomas lived for the last 13 years of his life at 12 Thornsett Road, Bromley, London, died on 27 January 1910, and was buried in Elmers End cemetery, near to cricketer WG Grace.
Mr Crapper's firm has been revived and has a Web site!
Wallace Reyburn, Crapper's biographer, is noticeably silent about the date of this patent. Fortunately it is possible at the old patent office to look up all the patents taken out by a particular person. Mr Crapper took out exactly nine plumbing patents, starting with one in 1881 (No. 1628) for ventilating house drains, and ending in 1896 with one (No. 4333) for an improved pipe-joint. None of his patents was No. 4990. None of his patents was for a valveless water-waste preventer (WWP).
During the 1880s various types of siphonic systems were being patented at the rate of about 20 a year---but none by Thomas Crapper.
George Crapper of Marlborough Works---Thomas' nephew---took out in 1897 a patent (No. 724) for "improvements in one or relating to automatic syphon flushing tanks." But this was more than 40 years after the first siphons.
In fact the first patent for a siphonic flush was taken out by Joseph Adamson in 1853, eight years before Crapper started his business, and 28 years before he took out his first patent.
So alas it seems almost certain that Thomas Crapper did not invent the siphonic flush; he certainly did not patent it, as he implied in his advertising.
Born in Edinburgh in 1773, Cumming moved to London and became an accomplished watchmaker in Bond Street. He wrote books about clock and watch work, about the effect on roads of carriage wheels with rims of various shapes, and on the influence of gravity. He became a magistrate and a Fellow of the Royal Society.
His water-closet had a pan with a sliding valve across the bottom. When the user arrived, it contained a few inches of water, held in by this valve. Having finished, the user pulled a lever to slide the valve open and release the contents of the pan to the trap below, and thence into the sewer. The same pull turned on the water to clean the pan, and the valve was then shut so that the pan contained some water for the next person.