light for sixty hours, and the expense, at a moderate price of oil, will be (allowing for coals, labour, &c.) not more for one burner than three farthings per hour.

"Such a burner will be equal in intensity of light to two Argand oil lamps, or to ten mould candles. "The expense of Argand oil lamps is usually admitted to be 13d. per hour each.

Supposing ten mould candles to be burning (at four to the pound, will be two and a half pounds, costing 2s. 11d.), one-tenth part will be consumed in each hour, and the cost of the light is then 3 d. per hour.

"If wax candles be employed, the expense of a quantity of light, equal to a gas burner for one hour, by the same mode of reckoning, allowing a candle to burn ten hours, and taking the price of wax candles at 4s. 6d. per pound, will cost about 1s. 2d.

"The account will stand thus:

8. d.

Argand burner, oil gas, per hour...... 0 0% Argand lamp, sperm oil, ditto........ 0 1

"In many cases it may be desirable to use a much smaller quantity of light than such an one above calculated upon might produce, and, instead of the light of ten candles, that of one or more may

be given, by using burners of a different description, and the expenditure of gas and the cost, will be reduced in proportion.

"The calculations, on the cost of light from oil gas are taken on the usual price of good whale oil; but it is observed, that cheaper oils will answer the purpose nearly as well.

"Mr. Deville, in the Strand, is inclined to estimate the average produce of gas from a gallon of oil at eighty cubic feet.

“A single jet burner, giving light equal to two and a half candles, consumes half a cubic foot per hour; a double jet, three-quarters of a cubic foot, to give twice the above quantity of light; and a treble jet requires one foot..

"The light of an Argand burner of coal gas, compared with one of spermaceti oil, may be estimated as two and a half to one, and of coal gas to oil gas as nine to five.

"A curious fact respecting Argand burners for gas is, that those with few holes consume a comparatively larger quantity of gas than those having a great number. Thus

Fifteen holes consume 2 cubic feet per hour.

Twelve...

Ten

21

..2, the holes being of

the same dimensions in each burner.*

• Journal of the Royal Institution, Vol. VII. p.313, 1819.

These extracts may perhaps be deemed more than sufficiently long, but their importance will become evident as we advance in the history of Oil Gas; for the statements which they contain gave rise to an interesting controversy, which rendered considerable service to Gas-lighting.

CHAPTER XIII.

mr. george LOWE'S REMARKS ON THE JOURNAL OF SCIENCE AND THE ARTS. MR. DAVID GORDON'S PATENT FOR PORTABLE GAS-VESSELS, &c.

In the communications which had appeared in the Journal of Science and the Arts, with a view to favour and to recommend the general introduction of oil gas, its advantages were so strongly portrayed, as to make it evident that the picture was sketched by partiality and shaded by prejudice, if interest did not furnish the colour as well as guide the pencil. But it also awakened suspicion in scientific and inquiring men, who were not likely to permit such glaring and apparently illusive delineations to be exhibited without minutely

scrutinizing and comparing them with the standard of truth. Hence the comparative qualities of coal and oil gas, with respect to their illuminating power and cheapness, became a subject of discussion in various public journals; and facts as well as arguments were opposed to assumed positions and unqualified assertions, which wanted the corroboration of evidence.

Mr. George Lowe, of Derby, was the first and most conspicuous person who entered this field of controversy; and his accurate and extensive knowledge of the subject peculiarly qualified him for engaging in the contest. In a letter addressed to the Philosophical Magazine, he rigidly and somewhat sarcastically examined the statements in the Journal of Science. He pointed out their disingenuousness and inconsistency with facts; and, by a few simple, but judicious calculations, on the comparative cost and illuminating power of coal and oil gas, he demonstrated the fallacy and impropriety of the fascinating and highly-coloured pictures which had been delineated of oil gas, particularly as regarded its cheapness, though he admitted that he was an admirer of it, and also allowed it a superiority with respect to its light. But as his mode of reasoning is characterised by a naïveté and force that are admirable, not to give them in his own words would be to do him injustice; and the following extracts not only con

vey some useful information, but will afford a fair specimen of his manner of treating the subject.

He commences his letter with observing, that his "remarks have arisen from the perusal of a most extraordinary fact-perverting paper among the highly interesting pages of the Quarterly Journal for July last." In reply to the assertion of its being "impossible to purify coal gas sufficiently for lighting close rooms," he observes, "fortunately, I have not far to wander for a confutation the most satisfactory. At this moment, my nose, my eyes, have as conclusive an evidence before them as any Argand lamp can produce, or man the most fastidious could desire; and that the whole of the brewery, offices, dwelling-house, and even the bed-rooms, partake of the comfort it affords. As to any the slightest degree of suffocating smell' arising from the gas, how can this be? for, when it tests one twenty-thousandth part of sulphuretted hydrogen, the lime for purifying is changed." He designates the writer as being "either an interested or an enthusiastic admirer of oil gas, and determined to add fictitious brilliancy to its brightness from the shorn beams' of poor coal gas."

He then proceeds to animadvert upon the statement of the economy of light from various sources, and says, "we are merely told that one gallon of whale oil will yield ninety cubic feet of gas." Mr.