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.
Ether is alcohol, two molecules deprived of H_{2}O [alcohol,
C_{2}H_{5}O HO; ether, (C_{2}H_{5})_{2}O]. Distilling spirit of wine
and sulphuric acid together, it seemed obvious that the sulphuric
acid should possess itself of the H_{2}O, and leave the ether. But on
this theory it was not possible to explain the invariable formation
of sulphovinic acid (a sulphate of ethyl) in the process, nor the
simultaneous distillation of water with the ether. Williamson proved
that the acid first combined with the alcohol molecule, setting
the water free, and that then an excess of alcohol decomposed the
sulphovinic acid thus formed into free sulphuric acid and ether, this
circuit proceeding continuously.