It should be mentioned that it was by the examination of Epsom salts that Black was led to his epoch-making discovery of the distinction between the alkaline earths, and also of fixed air, in 1754.
In Quincy’s “Dispensatory” (1724), medicinal waters like those of Epsom are described as Aquæ Aluminosæ. It is stated that there are many in England, scarce a county without them. The principal ones about London are at Epsom, Acton, Dulwich, and North-hall. They all “abound with a salt of an aluminous and nitrous nature,” and “greatly deterge the stomach and bowels.” But it is easy to take them too frequently, so that “the salts will too much get into the blood, which by their grossness will gradually be collected in the capillaries and glands to obstruct them and occasion fevers.” After some more advice Quincy adds—
“It is difficult to pass this article without setting a mark upon that abominable cheat which is now sold by the name of Epsom waters. Dr. Grew, who was a most worthy physician and an industrious experimenter, made trial how much salt these waters would leave upon evaporation, and found that a gallon left about two drams, or near, according to my best remembrance, for I have not his writings by me. He likewise found the salt thus procured answered the virtues of the water in its cathartic qualities. Of this an account was given before the Royal Society in a Latin dissertation. But the avaricious craft of a certain furnace-philosopher could not let this useful discovery in natural knowledge rest under the improvement and proper use of persons of integrity; but he pretended to make a great quantity for sale; and to recommend his salt translated the Doctor’s Lecture into English to give away as a quack-bill.”
Quincy proceeds to tell us how other competitors came in, and how the price was so reduced that what was first sold at one shilling an ounce, and could not honestly be made under (Quincy apparently refers to the salt made by evaporation), came down in a short time to thirty shillings per hundredweight.
Ether.
The action of sulphuric acid on spirit of wine is alluded to in the works of Raymond Lully in the thirteenth century, and in those attributed to Basil Valentine, by whom the product is described as “an agreeable essence and of good odour.” Valerius Cordus, in 1517, described a liquor which he called Oleum Vitrioli Dulce in his “Chemical Pharmacopœia.” This was intended to represent the Spiritus Vitrioli Antepilepticus Paracelsi. It was prepared by distilling a mixture of equal parts of sulphuric acid and spirit of wine, after this mixture had been digested in hot ashes for two months. Probably the product obtained by Cordus was what came to be called later the sweet oil of wine, and not what we know as sulphuric ether.
The first ether made for medicinal purposes was manufactured in the laboratory directed by Robert Boyle, and it is said that he and Sir Isaac Newton made some experiments with it at the time. A paper describing his ether investigations was published by Newton in the “Philosophical Transactions” for May, 1700. In 1700 a paper on ether was published by Dr. Frobenius in the “Philosophical Transactions,” and in the same publication in 1741 a further paper appeared giving the process by which Frobenius had prepared his “Spiritus Vini Ethereus.” Equal parts of oil of vitriol and highly rectified spirit of wine by weight were distilled until a dense liquid began to pass; the retort was then cooled, half the original weight of spirit was added, and the distillation again renewed. This process was repeated as long as ether was produced. Frobenius had been associated with Ambrose Godfrey in Boyle’s laboratory, and Godfrey had been supplying ether for some years, but he does not seem to have published his process. It was in Frobenius’s first paper, published in 1730, that the name of ether was first proposed for the product, which had been previously known as Aqua Lulliana, Aqua Temperata, Oleum Dulce Paracelsi, and such-like fancy titles. Frobenius, it was understood, was a nom de plume. Ambrose Godfrey Hanckwitz, Boyle’s chemist, sharply criticised Frobenius’s article, said it was a rhapsody in the style of the alchemists, and that the experiments indicated had been already described by Boyle. Godfrey was, in fact, at that time making and selling this interesting substance. In France, the Duke of Orleans, a clever chemist, who was suspected to have had some association with the famous poisonings of his time, and whose laboratory was at the Abbaye Ste. Genevieve, was the first to produce ether in quantities of a pint at a time.
Hoffmann’s “Mineral Anodyne Liquor,” the original of our Spiritus Ætheris Co., was a semi-secret preparation much prescribed by the famous inventor. He said it was composed of the dulcified spirit of vitriol and the aromatic oil which came over after it. But he did not state in what proportion he mixed these, nor the exact process he followed.
The chemical nature of sulphuric ether was long in doubt. Macquer, who considered that ether was alcohol deprived of its aqueous principle, was the most accurate of the early investigators. Scheele held that ether was dephlogisticated alcohol. Pelletier described it as alcohol oxygenised at the expense of the sulphuric acid. De Saussure, Gay-Lussac, and Liebig studied the substance, but it was Dumas and Boullay in 1837, and Williamson in 1854, who cleared up the chemistry of ethers.