ADVANTAGES OF GAS.

95

Since the foregoing experiments and calculations were made, the mineral oils of Americahave come into competition with gas, and in those places abroad where the increased costof gas-making necessarily raises the price as high as 12s. or 15s. per 1000 feet, petroleummay be a cheaper means of illumination than gas. It appears from experiments made inthe United States by Messrs. Booth and Garnett, recorded in the ‘Journal of the FranklinInstitute,’ to ascertain the relative economic values of mineral oil and gas, that where theprice of 15-candle gas is 9s. per 1000 feet, and refined petroleum is Is. 9 \d. per gallon,gas-light is twice as costly as the light produced by burning mineral oil. At the same time,the experimenters observe :—“ It would be a partial, and perhaps culpable, view of the sub-ject, if we were to omit a notice of danger in the use of mineral oils, whether obtained fromcoal or petroleum.” They further state:—“ It is not to be apprehended in the slightestdegree that the oils will supersede the use of gas, especially in cities and towns, nor even inmany country houses.” The following Table shows the value of gas as an illuminatingagent compared with petroleum and candles :—

Name of Material.

Quantity for an equalamount of light.

Price of unit of quantity.

Cost of quantityfor equal light.

Gas.

Petroleum.

o rSpermaceti.

'S Paraffin.

Cj ^Adamantine.

1000 cubic feet,gals.

37 lbs.

36* „

47 „

2.25 dols. per 1000.0.45 per gal.

0.50 ,, lb.

0.32 „ „

0.25 „ „

2.25 dols.1.07

18.50

11.68

11.75

The magnesium light also threatens to compete with gas; but at present, neither the priceat which magnesium can be manufactured, nor the modes of its combustion, make it aformidable rival. The results of a series of experiments undertaken by Br. Franklandwere recorded in vol. xiv. of the ‘Journal of Gas-Lighting,’ page 102, in which it is stated,that the light produced by the combustion of 2i ounces of magnesium is equal to that of20 lbs. of stearine candles, and to 404 cubic feet of gas. The price of the new metal wasthen one guinea an ounce, and it was assumed by Dr. Frankland, that with the utmost im-provements that can be made in its production, according to the only process known, of redu-cing it by means of sodium, it could never be sold for less than 2 s. an ounce, at which pricethe light, though it would be considerably cheaper than that of candles, would still be nearlythree times dearer than coal gas in London. The dazzling brilliancy of the rays of themagnesium light would also prevent its application for the general purposes of illumination.The same objection applies to the lime-light and to the electric light, neither of which canbe produced nearly so economically as an equal amount of light by gas.

In addition to the advantages which gas presents as an economical means of illumination,it is also very applicable in many circumstances as a cheap and extremely convenient sub-stitute for ordinary fuel. It cannot, indeed, compete with coal in the common purposes ofcooking, and of heating apartments; but when an occasional fire is required for a shorttime, the combustion of gas is not only more convenient, but is less costly than coal. Thefollowing statement, which was the result of many experiments, shows the relative cost of