Epsom Salts after Epsom Spa
In his book Epsom Wells, Maurice Exwood says that a Dr. N. Grew in 1679 read a paper to the Royal Society on the salts of mineral waters which set out the different constituents. Grew expounded on this in a work published in 1695 and established the name ‘Epsom Salts’ for what we now know as the salt magnesium sulphate, a constituent of most spa mineral waters. Maurice Exwood goes on to explain how Grew is reported to have discovered a well at Acton with water having the same properties as the Epsom water and to have set up a works there to produce 20,000 lbs of salts per annum. Other wells of a similar nature were discovered and a chemist, Francis Moult, claimed he had been manufacturing and selling the salts for years using the waters of Shooters Hill Well prior to Grew going into production. Furthermore, in 1723, a John Brown reported to the Royal Society that Epsom Salts were being manufactured from the ‘bitterns’ left after crystallisation of common salt from sea water – in other words as a byproduct of the manufacture of common salt.
It is probably no coincidence that the number of visitors to Epsom spa declined rapidly after 1723. Maurice Exwood also provides the information that Epsom Salts are still sold under that name, not just for traditional purposes, but as an ingredient for other useful medicaments and are included in some rose fertilisers.
After reading Maurice’s book I thought no more about Epsom Salts until idly browsing the entries under Epsom on the internet and coming across a reference to the Epsom Salt Industry Council based at Rutherford, New Jersey, USA, which has numerous members, many able to deliver Epsom Salts by the truckload. It made me wonder about the present day uses of Epsom Salts. Given the diet of many Americans, I can think that they might find the salts helpful when used in the traditional way (as a laxative), but supplies by the truckload?
It appears that magnesium sulphate has a variety of modern uses, including the finishing of cotton fabrics and in the dyeing of fabrics. It is added to certain types of cement and is used in the leather industry. One of its medical applications is in surgery as a wet dressing for wounds. Maurice mentions its inclusion in rose fertilisers. This arises from its ability to supply magnesium to magnesium deficient soils and has led to the widespread use of magnesium sulphate on many crops: it has proved particularly beneficial for citrus fruits, potatoes and clover hay for which it has brought about increased yields. Magnesium is a basic part of chlorophyll and so is essential to all plants. The deficiency is most likely to occur in acid soils.
There are numerous sources of magnesium sulphate: Epsom has never been a commercial source. In some parts of the world it is found as a natural crystalline deposit, and these include Stassfurt (Germany), Kentucky and British Columbia. These natural deposits have a variety of names, such as kieserite, epsomite and hairsalt.
When magnesium sulphate is produced from sea water it is done by progressive evaporation. Seawater contains something like 3% of solids. (If all the seas dried up the entire ocean would yield salt amounting to about 15 times the bulk of the entire continent of Europe above high-water mark). The main constituent of the salt is common salt (sodium chloride). Magnesium sulphate forms about 6.5% of the total solids. Separation of the different salts is possible because each one has its own saturation point in the solution. The evaporation is done either in open pans or in vacuum vessels. Either method needs careful control to get the quality of salt required.
Exwood, Maurice, Epsom Wells (Epsom & Ewell Borough Council, 1989).
Sarah Mapp, the bone-setter
In my book, Epsom Past, I gave a brief account of the life of Sarah Mapp. My wife, Barbara, has recently come across the following reference to her in The History of Signboards by Jacob Larwood and John Camden Hotten, published in 1866, in connection with an inn in Whitechapel:
On Friday, several persons who had the misfortune of lameness, crowded to the White Hart Inn in Whitechapel, on hearing Mrs. Mapp, the famous bone-setter, was there. Some of them were admitted to her, and were relieved as they apprehended. But a gentleman who happened to come by declared Mrs. Mapp was at Epsom, on which the woman thought proper to move off. The genuine Mrs. Sarah Mapp was a female bone-setter, or ‘shape mistress’, the daughter of a bone-setter of Hindon, Wilts. Her maiden name was Wallis. It appears that she made some successful cures before Sir Hans Sloane, in the Grecian Coffee- house. For a time she was in affluent circumstances, kept a carriage and four, had a plate of ten guineas run for at the Epsom races, where she lived, frequented theatres, and was quite the lion of a season. Ballads were made upon her, songs were introduced on the stage, in which the ‘Doctress of Epsom’ was exalted to the tune of Derry Down; in short, she was called the ‘Wonder of the Age’. But alas! The year after all this éclat we read in the same Grub Street Journal, that had recorded all her greatness ‘December 22, 1737. Died last week at her lodgings, near the Seven Dials, the much-talked of Mrs. Mapp, the bonesetter, so miserably poor, that the parish was obliged to bury her’. Sic transit gloria mundi.