SANITARY ASPECTS. Toward the close of the nineteenth century the attention both of sani tarians and of those interested in gas manufac ture was directed to the sanitary aspects of the use of illuminating gas. The importance of this phase of the subject had recently been increased by the frequent substitution of water-gas for ceal-gas. In water-gas the most poisonous agent —carbonic acid—is increased, as compared with coal-gas, from 6 or 7 per cent. to about 30 per cent. This change, however, was not necessary to make illuminating gas an active poison to breathe. The danger in the use of illuminating gas arises from two sources: (1) From unburned gas which escapes into the atmosphere through defective pipes or fixtures, or through burners accidentally open, and (2) from vitiation of the atmosphere through the products of burning gas.
The National Board of Fire Underwriters has published a table of gas losses compiled from data furnished by fifteen companies, which shows that over 14 per cent. of the total product of gas plants leaks into the streets and houses of the cities supplied. The danger to houses from escaping gas is much greater in the winter time, when the street surface is frozen, and when houses, on account of their higher temperature, act as chimneys to draw in the ground air, and with it the gas which has leaked into the soil. Gas thus escaping may follow water or sewer pipes, and enter even those houses which have no gas connections.
In order to remove the constant menace to life and property, through explosion and asphyxia tion, which is afforded by leaky gas-mains, the whole matter should be under the strictest sur veillance and control by the public. The intro duction in our large cities of subways for under ground pipes and wires would remedy the evil by rendering gas-mains easily accessible for con stant inspection. In this way the slightest leak would be detected. The danger of deterioration of the mains through rust. and of their breaking through settlement of the soil, would also be removed.
While the consumption of gas does vitiate the atmosphere of a room to a certain extent, an ideal system of ventilation is possible, in which burning gas is not a hindrance, but an essential part. An example of such a system
is the British Houses of Parliament, in which, by means of flues placed over the jets, the heat or surplus energy of the gas-flame assists in producing a pure atmosphere. A similar system of ventilation could be carried on in an ordinary room with a thirteen-foot ceiling, in conjunction with the chimney in the room, and the combus tion of one cubic foot of gas could be made, by a suitable flue, to change the atmosphere of a room 15 X 15 X 11 feet once per hour. In this event, the three feet per hour consumed by an incandescent burner could be made abundantly to light and ventilate that space.
BIBLIOGRAPHY. Journals devoted to the subBibliography. Journals devoted to the sub- ject of the manufacture and distribution of gas appear in all the leading languages, and of these the Journal of Gas Lighting (London) was first issued in 1849. For a full description of the subject of gas-lighting, see: Articles on "Gas" in Encyclopmdia of Chemistry (Philadelphia, 1877) ; Spon's Encyclopmdia of Industrial Arts (London and New York, 1879) ; Thorp, Diction ary of Applied Chemistry (London, 1891) ; Wag ner, Handbook of Chemical Technology (New York, 1895) ; Richards, A Practical Treatise on the Manufacture and Distribution of Coal Gas (London, 1877) ; Kings Treatise on the Science and Practice of the Manufacture and Distribu tion of Coal Gas, edited by Newbigging and Few trell (London, 1878) ; Colyer, Gas Works: Their Arrangement, Construction, Plant, and Ma chinery (London, 1884) ; Chester, Bibliography of Coal Gas (Nottingham, 1892) ; Atkinson Butterfield, The Chemistry of Gas Manufacture (Philadelphia, 1896) ; O'Connor, The Gas Engi neer's Pocket-Book (New York, 1898) ; Wank lyn, The Gas Engineer's Chemical Manual (Lon don, 1888) ; Dent and others, "Lighting," in Chemical Technology, vol. ii. (Philadelphia, 1895) ; Hunt, "Gas Lighting," in Chemical Tech nology, vol. iii. (Philadelphia, 1900).