Sulphuretted Hydrogen Gas.
This gas is transparent and colourless; it has the property of inflammability, and when set on fire in the open air, burns with a bluish flame, and deposits a certain portion of sulphur. It is distinguished by an excessively fœtid smell, which has been aptly compared to that of rotten eggs. Its habitudes with other gases are interesting and important; by admixture with chlorine, it immediately undergoes decomposition, yielding its hydrogen, so as to form hydro-chloric acid (muriatic acid), and consequently depositing its sulphur; with ammoniacal gas it combines, and forms an hydro-sulphuret of ammonia; when mingled with sulphurous acid gas, the hydrogen of the former combines with the oxygen of the latter, and the sulphur of both is precipitated; when passed over ignited charcoal it is converted into carburetted hydrogen gas, and sulphur is deposited.
It is soluble in water, and the solution precipitates the different metals from their saline solutions, in the form of sulphurets; a property which at once distinguishes this gas from every other.
It has been long considered a very energetic poison, and it would, at the same time, appear to be a very insidious one; for sensibility is quickly destroyed by it, without any previous suffering. We are acquainted with a chemist who was suddenly deprived of sense, as he stood over a pneumatic trough, in which he was collecting the gas. It would seem to act upon the nervous system through the medium of the blood, in which it is extremely soluble. It constitutes the particular gas of privies, and is the immediate cause of those accidents which we have already described in a former part of this work, vol. 1, page 100; since the printing of which we have heard of the death of four persons from emptying a privy at Brompton. This gas will be sometimes developed during the imperfect combustion of wet coals[[504]]; and it was probably owing to its presence, or to that of carburetted hydrogen, that the accident arose which is recorded by Mr. Sutleffe in the Medical Repository. “He was hastily summoned to a neighbouring family at bed-time, where he found a female domestic labouring under a shrill, laborious inspiration; she had taken up from a good kitchen fire, a panful of live coals, from which a sudden suffocating blast seized her.”
Carburetted Hydrogen Gas.
This gas is developed by several chemical processes. We have just stated that if, during the burning of charcoal, moisture be present, it is evolved in abundance. It appears to be particularly fatal to animal life. Dr. Beddoes made many experiments upon the subject, from which it would seem to destroy life by rendering the muscular fibre inirritable without producing any previous excitement. In order to decide this question, Sir Humphry Davy[[505]] ventured to take three inspirations of the gas produced from the decomposition of water by charcoal. “The first inspiration produced a sort of numbness and loss of feeling in the chest, and about the pectoral muscles; after the second,” says he, “I lost all power of perceiving external things, and had no distinct sensation, except a terrible oppression on the chest; during the third expiration, this feeling disappeared; I seemed sinking into annihilation, and had just power enough to drop the mouth-piece from my unclosed lips. There is every reason to believe, that if I had taken four or five inspirations, instead of three, they would have destroyed life immediately, without producing any painful sensation.”
Chlorine—Oxy-muriatic Acid Gas.
This gas, which is now considered as an elementary body, has received from Sir Humphry Davy the name of chlorine, from the green colour which characterises it. Its odour is so penetrating and insupportable that it is impossible to respire it, even when considerably diluted with atmospheric air, and yet it will support combustion. It discharges vegetable colours, whence it forms the basis of various bleaching preparations. According to the experiments[[506]] of M. Nysten, this gas is not absorbed when respired pure, but appears to act only by irritating the bronchiæ locally; and so energetic is its action, that the animal dies before there is sufficient time for asphyxia to take place from the circulation of black blood. When it is respired in a dilute form, it produces a severe cough, and, according to Fourcroy, it occasions a phlegmonic inflammation of the bronchial membranes. The death of the ingenious and indefatigable Pelletier was occasioned by his accidentally inhaling a proportion of this gas; a consumption was the consequence, which in a short time proved fatal. In the London Medical and Physical Journal for November, 1821, a case of a person is recorded who was poisoned by bleaching liquor.
Sulphurous Acid Gas.
The gas is generated by the combustion of sulphur. It is colourless; has a pungent smell, resembling that of burning sulphur, and is very soluble in water. It would appear to destroy life by a peculiar action on the blood.