OXYGENA′TION. Syn. The act or process of combining with oxygen. Formerly it was of more general application than the word ‘oxidation,’ with which it has been regarded as synonymous. ‘Oxygenation’ is, however, at the present day practically obsolete.
OXYGENI′SED LARD. Syn. Oxygenated axunge; Axungia oxygenata, L. Prep. (Ph. Bat. 1805.) From prepared lard, 16 parts, melted over a slow fire, and then mixed with nitric acid, 1 part; the combination being promoted by constant stirring with a glass rod, until it ceases to affect litmus paper. It should be extremely white, and should be kept in the dark. See Ointment of Nitric acid.
OXYHYDROGEN BLOWPIPE. See Blowpipe. Deville and Debray (‘Ann. Ch. Phys.’ [3], lvi, 385) employ the oxyhydrogen blowpipe in the following manner for effecting the fusion of platinum and the refractory metals which accompany it. The apparatus consists of the blowpipe C (see below), a furnace ABD, and a crucible GHI. The blowpipe is composed of a copper tube about half an inch in diameter, terminating below in a slightly conical platinum jet about 11⁄2 inch long. Within this tube, which is supplied with hydrogen or coal-gas through the stop-cock H, is a second copper tube C′ for supplying oxygen, terminated also by a platinum nozzle with an aperture of about a twelfth of an inch in diameter.
The furnace ABD consists of three pieces of well-burnt lime of slightly hydraulic quality, which may be turned at a lathe with ease. The cylinder A is about 21⁄2 inches thick, and is perforated by a slightly conical hole into which the blowpipe fits accurately, passing about half-way through the thickness of the mass. A second somewhat deeper cylinder of lime, B, is hollowed into a chamber wide enough to admit the crucible, and leave an interval of not more than a sixth of an inch clear around it. KK are four apertures for the escape of the products of combustion.
The outer crucible HH is also made of lime, but it contains a smaller crucible I of gas coke, provided with a cover of the same material; and in this the substance to be used is placed, the crucible resting on the lime support D′. The conical cover G is made of lime, and its apex should be placed exactly under the blowpipe jet, at a distance from it of 3⁄4 to 11⁄2 inch.
The different pieces of the furnace must be bound round with iron wire to support them when they crack. The oxygen is admitted under a pressure of a column of 16 inches of water. The temperature is gradually raised to the maximum, and in about eight minutes from this time the operation is complete.
By employing a jet of mixed coal-gas and oxygen (EQ, see engr.) in a furnace of lime, Deville and Debray succeeded, at an expense of about 43 cubic feet of oxygen, in melting and refining, in 42 minutes, 25·4 lbs. avoirdupois of platinum, and casting it into an ingot in a mould of gas coke; and much larger masses have since been melted by this method. Lime is so bad a conductor of heat that if a cup of lime not more than 0·8 inch thick be filled with melted platinum the exterior scarcely rises beyond 300° Fahr. (Miller’s ‘Elements of Chemistry,’ 3rd. ed., pt. ii, p. 825.)
OX′YMEL. Syn. Oxymel, L. An acidulous syrup made of honey and vinegar. There are only two oxymels in the last Ph. L. The ingredients in an oxymel should be of such a character, and in such proportions, as to produce a mixture of the proper consistence without evaporation.