There is another system of producing illuminating gas, which, though not used extensively, is still in vogue. The gas is obtained by the complete evaporation of suitable spirits. Such fluids arc obtained from crude oils by fractional distillation. They are highly inflammable bodies, and possess the Germany the use of the gas was at one time entirely prohibited, and in oar own country an Order in Council, dated February 26, 1897, was made, prohibiting the keeping of carbide of calcium without a license. That stringent Order was somewhat relaxed in the following July, the Order now in force running thus: -

"The quantity of carbide of calcium which may be kept without a license shall be as follows: - (a) Where it is kept in separate substantial hermetically-closed vessels containing not more than 1 lb. each, ........ ..... 5 lbs,

(A) Where it is kept otherwise, ...... None.

The necessity for these regulations is manifest when we remember that moisture, acting on the carbide of calcium, liberates acetylene, which, when mixed with air in certain proportions, provides a highly-explosive compound.

A more recent Order in Council (dated November 26, 1897) deals with liquid or compressed acetylene, and is so important that it must be quoted almost in extento: -

"Whereas acetylene when liquid or subject to a certain degree of compression is specially dangerous to life or property by reason of its explosive properties.

Now, therefore. Her Majesty is pleased by and with the advice of Her Privy Council to order and declare, and be it ordered and declared as follows: -

Acetylene when liquid or when subject to a pressure above that of the atmosphere capable of supporting a column of water exceeding one hundred inches in height and whether or not in admixture with other substances, shall be deemed to be an explosive within the moaning of the said Act, subject to the following exception: that if it be shown to the satisfaction of the Secretary of State that acetylene, declared to be explosive by this Order when in admixture with any substance, or in soy form or condition, is not possessed of explosive properties, the Secretary of State may by Order exempt such acetylene from being deemed to be an explosive within the said Act.

And whereas by section 43 of the Explosives Act, 1875, it is provided that Her Majesty from time to time by Order in Council, may prohibit, either absolutely or except in pursuance of a license of the Secretary of State under the said Act, or may subject to conditions or restrictions the manufacture, keeping, importation from any place out of the United Kingdom, conveyance, and sale, or any of them, of any explosive which is of so dangerous a character that in the judgment of Her Majesty it is expedient for the public safety to make such Order.

And whereas it is in the judgment of Her Majesty expedient for the public safety that acetylene, when an explosive within the meaning of this Order, shall he prohibited.

Now, therefore, in pursuance of the above-mentioned provision of this Act, Her Majesty is pleased by and with the advice of Her Privy Council, to order and prescribe that acetylene declared to be an explosive by this Order shall be prohibited from being manufactured, imported, kept, conreyed, or told" - ED.

property of being entirely converted into gas. They have a very low flashing point, many degrees below that of freezing point, and are readily volatile at ordinary temperatures. The two principal kinds of petroleum spirit used for the purpose are gasoline and carburine. The former has a specific gravity of 660, and the latter of 680. The liquid is invariably stored in the open air. As gasoline requires another step in its preparation beyond carburine, and is consequently more expensive, the latter (or 680 spirit) is most frequently used.

The apparatus used for the conversion of this liquid into gas for illuminating purposes is very compact, consisting of a small gasholder 3 feet 6 inches in diameter, capable of holding from six to eight cubic feet of gas. The columns of this gasholder, currying the guide-runners, support a platform, on which a diminutive retort is placed. The retort is heated by atmospheric burners. A pipe leading from the spirit-tank, which is fixed at a higher level, enters the retort, the supply of liquid being regulated by a valve of an ingenious design and careful workmanship. The outlet from the retort is placed at the top, and is connected to the inlet of the gasholder below. Upon starting the apparatus, the supply of gas is automatic. The burners under the retort are ignited, and a temperature between 400° and 500° Fahr. imparted to the vessel. The cock admitting the liquid from the tank is opened, and the supply of gas is controlled by the valve. The valve-lever is connected to the gasholder, and the rising or falling of the holder actuating the valve decreases or increases the flow of spirit into the- retort. The carburine, coming in contact with the heated surface of the retort, is immediately and completely vaporized into a rich illuminating gas, which, by the pressure created, passes into the holder.

The rapidity with which the supply of gas can be obtained, and the readiness with which the process will adapt itself to the consumption of one or three hundred lights, have procured for this system a considerable amount of patronage. The gas, however, although of a rich illuminating power (being of some 60 to 70 candles in value), is expensive, casting from 6s. to 7s. per thousand cubic feet, according to carriage, which is considerable with this class of inflammable material.

Of all the methods described for producing illuminating gases, this system demands the least attention or cleaning. The spirit is entirely evaporated into gas, and leaves no deposit in the holder or retort. It is quickly brought into action, and as quickly stopped. It will produce a sufficient quantity for 300 lights, or for maintaining only the two atmospheric burners necessary for heating the retort. The retort and gasholder can be placed in the cellar of the house without danger or nuisance. Ordinary oil-burners, or mushroom regenerative burners, may be used for its consumption.