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.