1 Lowitz procured aether of this gravity by the following process. To aether reduced to .746 specific gravity by means of carbonate of potassa in the usual method he added as much dry powdered chloride of lime as it would dissolve. On standing, the mixture separated into two parts; the alcohol holding the salt in solution sunk to the bottom : the aether swam on the surface. When separated from the inferior liquor, its specific gravity was now only .632 in the temperature of 60°. Thomson's Chymistiy, 4th ed. ii. 443.

The theory of the formation of aether is still unsettled. It has been contended, that the balance of affinities between the constituents of the alcohol is broken by the acid, the oxygen of which attracting a portion of the hydrogen of the alcohol forms water; while a portion of its carbon, at the same time set free, forms the residuary black matter found in the retort; and, by a new combination of the remaining hydrogen, carbon, and oxygen, the aether is produced. This explanation, however, which supposes a partial decomposition of the acid, has been denied by Fourcroy and Vauquelin, who, from a series of very ingenious experiments 1 concluded, that the acid suffers no decomposition, except towards the end of the process, which is to be attributed to the carbonaceous matter collected in the retort; but that it produces the decomposition of the alcohol without being itself decomposed, by the exertion alone of a disposing affinity, abstracting water or its elements from the alcohol. The aether, according to them, is the result of the new combination of the components of the alcohol, part of its oxygen and hydrogen first combining to form water, and a large portion of its carbon being separated without entering into any new combination; so that aether differs from alcohol only in containing a greater proportion of hydrogen and oxygen, and a smaller proportion of carbon.

Thus, alcohol, according to the analysis of Saussure, is a compound of carbon 52.17, oxygen 34.79, and hydrogen 13.04 in 100 parts; or of one equivalent of etherine = 28.48 + 2 of water = 18 = 46.48 : whilst aether consists of carbon 67.98, oxygen 17.62, and hydrogen 14.40: or of one equivalent of etherine = 28 + 1 equivalent of water = 9 = 37.48: or alcohol consists of 2 atoms of carbon = 12.24 + 1 atom of oxygen = 8, + 3 atoms of hydrogen = 3, making the equivalent = 23.24; whilst aether consists of 4 eq. of carbon = 24.48 + 5 of hydrogen = 5 + 1 of oxygen, making the equivalent = 37.48; or it is a hydrate of etherine. Mr. Hennel found that two equivalents of sulphuric acid being added to two of alcohol, the acid undergoes great changes, and is converted into sul-phovinic acid, which is a compound of sulphuric acid and a carburet of hydrogen; and he supposes that it is a stage in the formation of this ether. It is present in greatest quantity when the-meterials are first mixed; but as the distillation proceeds and the aether is formed, the sulphovinic acid diminishes in quantity, until it entirely disappears. (See Journ. of Science, vol. xxi. p. 331.) The sulphurous and carbonic acids, and the charry residue formed in the process, are produced by the decomposition of a portion of the alcohol by the sulphuric acid, which is set free at the end of the process.

Berzelius regards aether as a compound of ethule, a substance consisting of 4 eq. of carbon + 1 of hydrogen, and the addition of 1 eq. of oxygen forms aether; or in other words, that aether is a protoxide of ethule.

1 Annates de Chimie, xxiii. 203.

Qualities.- Aether has a fragrant, penetrating odour, and a hot, pungent ta9te. It is colourless and perfectly limpid; and is the most volatile of liquids, drying immediately if poured on the hand, and producing a great degree of cold by its evaporation. Its sp. gr. is from 0.750 to 0.632 when perfectly pure: but it is seldom procured in the shops under 0.733. When it is of a density 0.720 it boils in the open air at 96°, and in vacuo at 20°, a temperature 12 degrees below the common freezing point; and, but for the pressure of the atmosphere, it would always be in a gaseous form. When cooled down to 46° below zero of Fahr., aether congeals in brilliant transparent plates. It is extremely inflammable, taking fire on the approach of an ignited body; a circumstance which requires to be attended to in pouring it from the phial to a glass by candle-light. During its combustion, water and carbonic acid are formed, and traces of charcoal are left behind. It. unites with alcohol in every proportion, and also readily mixes with ammonia; but ten parts of water take up or dissolve one only of aether.

It dissolves balsams, wax, volatile oils, bitumens, camphor, extractive, gum-resins, resins, sulphur in small proportions, narcotina and bichloride of mercury, but it does not dissolve the fixed alkalies. It is decomposed by sulphuric acid, which converts it into sweet oil of wine.1 Aether is sometimes adulterated: if it contain sulphuric acid from imperfect rectification, this may be detected by a precipitate being formed on the addition of solution of baryta; when alcohol is present, a milky solution is formed with phosphorus, which is not the case when it is pure. It should be kept in an obscure place, for, when exposed to light, in a bottle partially filled, it absorbs oxygen, and acetic acid is generated.

Medical properties and uses.- Sulphuric aether is stimulant, narcotic, and antispasmodic. In large doses its operation resembles alcohol, but it is more diffusable, and its effects are less permanent. It is beneficially employed as a cordial in typhoid and low fevers, particularly when nausea, subsultus

1 When sulphuric and hydrochloric aethers are mixed together in equal proportions, the evaporation is very rapid, and a degree of cold considerably below o of Fahrenheit is produced.

tendinum, and other spasmodic symptoms are present. As an antispasmodic, it relieves the paroxysm of spasmodic asthma, whether it be taken into the stomach, or its vapour only be inhaled into the lungs; in which latter form it is also useful in simple dyspnoea and in catarrh. Much caution, however, is required in inhaling the vapour of aether, as the imprudent inspiration of it has produced lethargic and apoplectic symptoms. It is employed with advantage in hysteria, tetanus, cramp of the stomach, hiccough, and in cholera morbus, to check the vomiting; and it also allays the violence of seasickness. The usual dose of sulphuric aether is from xx. to f3j.; but it has been given in much larger doses with the most beneficial effects: and in all cases the dose must be repeated at short intervals to produce the full effect of the remedy. As an external application, aether acts either as a stimulant or a refrigerant, according to the mode in which it. is applied. The first occurs when it is prevented from evaporating, by being confined over the spot to which it is applied: in which case it often proves useful in relieving headache and other muscular pains : the second, its refrigerant effect, is produced by its rapid evaporation, on which account it is applied to burns, and to assist in the reduction of strangulated hernia. We have seen it produce almost immediate relief in earache, when dropped into the external meatus.

Officinal preparation. - Spiritus Aetheris Sulphurici comp. L.