The illuminating gas hazard to life and property is explained in clear and intelligent shape by Fire Marshal Davis of Ohio, as follows:
"The swinging gas jet with more than one movable joint is safe in a building only when the gas is shut off at the curb, and one with a single joint should have a stop on each side to prevent its being turned against goods or the wall, unless it is furnished with a glass globe or wire hood. The fixture which causes the most earnest criticism from fire marshals while making inspections, is the swinging jet used alternately to light the coal bin and the furnace door in city dwellings. They usually find spots of char made by it at some part of the woodwork. A gas jet will first char wood which is too close to it and afterward will fire the charcoal it has formed. One having in mind the fact that charcoal is necessary to the explosion in gunpowder or its liability to spontaneous combustion cannot view its formation over a gas jet or under a gas stove without apprehension. A jet should not be within 2 1/2 feet of the ceiling. The greatest distance at which a gas jet is reported as having set fire to a ceiling is 28 1/2 inches.
Gas does not freeze; neither do gas pipes. What may freeze is the vapor of water carried by all gas in larger or smaller percentages. This watery vapor is condensed as frost on the inside of a cold pipe and may build up enough to close it. A very few degrees of heat will reconvert it into water, and when such conversion takes place, a pipe which may have been temporarily closed is open again and permits gas to pass through. This happens frequently in dwellings and explains why a gas light turned low will sometimes go out and gas be subsequently found flowing through the burner. There are many safe lights for the bedroom, and gas is so unsafe that its use for that purpose can only be attributed to ignorance of the danger it involves at all seasons, but especially in winter. The number of fatalities from the leakage of illuminating gas is not only large but increasing. An investigating committee in Boston found that a moderate increase in pressure caused leakage in 89 per cent of all homes examined. One part of gas with six of air makes an explosive compound.
Necessary to the appreciation of the different degrees of danger, from having one of the several kinds of gas in a dwelling, is a knowledge of the constituents of each. When coal is roasted in a retort, coke, tar, ammonia liquor and illuminating gases are produced. These gases are passed from the retort through an iron pipe to the bottom of a large horizontal pipe half filled with water, in which most of the tar and ammonia settle. The gases then pass through a series of tall iron pipes, which cools them; up through a tower filled with coke, down which the water trickles (the 'scrubber'), which dissolves out the ammonia and other soluble gases: then through the purifiers, in which lime and hydrated oxide of iron absorb most of the carbon, dioxide of iron and sulphur compounds; then into the large gas holders.
This product, ready to be pressed into the mains is, speaking broadly, hydrogen one-half, natural gas one-third, with 6 to 11 percent, carbon monoxide which slays its thousands each year, and 3 to 11 per cent. of heavy hydrocarbon (olefiants). The first three in burning produce heat, but practically no light without the hydrocarbons, which contains ethylene. The fine particles separated from the ethylene by becoming white hot give off light, and, not being entirely consumed, unless the gas is mixed with 15 times its volume of air, part of them float away as pure carbon (soot).
Within a few years the practice of mixing water gas with coal gas, or using it separately in the interest of economy, has become general. This at least quadruples its dangers, as shown by chemical analysis and by the alarming increase in the number of gas asphyxia-tions. Water gas is made by forcing steam through charcoal which is at a white heat. The atoms of oxygen in the water, which is in the form of steam, unite with atoms of carbon from the charcoal to form carbon monoxide, liberating the atoms of hydrogen. When piped into homes it is 44 per cent carbon monoxide. So 2 per cent of water gas in the air will kill an adult, because .65 per cent of carbon mon-oxide destroys life. "