"One important advantage gained by the cir cumstance that so small a quantity of gas being necessary for the burners, the gasometer required may be small in proportion. The gasometer is the most bulky part of a gas apparatus, and that least capable of concentration; it occupies room to the exclusion of every thing else. It, in a great number of cases, brings the size of the apparatus within what can be allowed in private houses; and, in consequence of the rapidity with which the retort can be worked, the gasometer may again be reduced to a still smaller size.

"Another advantage gained by the small quantity of gas required for a flame, is the proportionate diminution of heat arising from the lights. The quantities of heat and light produced by the combustion of inflammable gases, are by no means in the same constant relation to each other; one frequently increases, whilst the other diminishes; and this is eminently the case when coal gas and oil gas are burned against each other. The quantity of heat liberated is, speaking generally, as the quantity of gas consumed, and this is the greatest with the coal gas; but the quantity of light is nearly as the quantity of carbon that is well burnt in the flame; and this greatest in the oil gas.

"The very compact state in which the apparatus necessary for the decomposition of oil can be placed, the slight degree of attention required, its

certainty of action, its cleanliness, and the numerous applications it admits of in the use of its furnace for other convenient and economical purposes, render it not only unobjectionable, but useful in manufactories and establishments; and these favourable circumstances are accompanied, not by any inferiority in the flame or increased expense, but by an improved state of the first, and saving in the latter."*

In short, the writer concludes by stating that the only residuum in the retorts is a small quantity of carbon; and the only products besides the gas are a minute quantity of sebacic and acetic acid,† all of which are easily separated by passing the gas through a vessel containing water. How far some of the particulars contained in the preceding statement are consistent either with truth or candour, the public, though unable at that time to form an estimate, have since been qualified to decide by the indubitable evidence of facts. Certain qualities unquestionably belong to oil gas, which must occasion it always to be admired; and it possesses advantages which, in many cases and situations, must ever render it an object of great

* Journal of Science and the Arts, Vol. VI. page 108,' 1819.

↑ Whoever may have encountered this residuum of oil gas need not be told how far it will bear a comparison with sulphuretted hydrogen in its odoriferous qualities.

utility; therefore it needed not to be invested with such as do not belong to it. Besides, by attempting to depreciate the value of coal gas, and by ascribing to it properties and inconveniences of which it was divested, or could be so, tended only to disclose the views of those who endeavoured to make the degrading and unjust comparison. It seemed as if oil gas, and its patent apparatus, were to be obtruded and recommended by a system similar to that which had been formerly employed with regard to coal gas by Mr. Winsor; abating, however, something of his extravagancies of expression, and assumption of mystery. In some respects a striking resemblance will be recognized; but knowledge had now been too widely diffused, and the public mind had become too enlightened, for plausible representations to receive unlimited credit without examination, whatever might be the character of the writer, or however elegant his phraseology. That a journal professedly devoted to science and the arts, and so highly respectable for the useful and important information which it generally conveyed, should be made the vehicle of interested and fallacious purposes, was the occasion of much serious and deep concern to many who were its sincerest friends and admirers.

CHAPTER XII,

EXTRACTS FROM THE Journal of SCIENCE AND THE ARTS RELATIVE TO GAS-LIGHT ILLUMINATION, WITH REMARKS.

The writer of the article contained in the preceding chapter is still unknown to the public, and perhaps it is now of little consequence who he was; but the object in quoting it has been to display some of the means which were first employed to advance oil gas into public notice. How far they comported with the dignity of the scientific character, or even accorded with honourable commercial competition, are questions which each individual will decide as his feelings and views may influence the conclusions of his judgment. Suffice it to observe, that the same plan was pursued, and similar statements were made, in a subsequent publication, which, if style and sentiment afford any indications to judge of an author, the writer of the former article may be distinctly recognized. It contains, however, some additional remarks with respect to the advantages of oil gas, which are worthy of notice. The article is entitled "A few Facts relating to Gas Illumina

tion ;" and the most prominent parts will be found in the following extracts.

"The producing from coal an aëriform fluid, which could be distributed at pleasure in every direction, for the purpose of economical illumination, has justly been ranked amongst the greatest benefits which the science and enterprise of this country have conferred upon mankind.

“Important as is the discovery, many defects and inconveniences have arisen on its adoption; coals contain a large proportion of sulphur, which is volatalized with the gas, and it has hitherto been found impossible to purify it sufficiently for lighting close rooms. The suffocating smell, and the property which it has of tarnishing every thing metallic, exclude its use from dwelling-houses, on account of the injury it would do to our health, our furniture, books, pictures, plate, paint, &c. At the same time that the gas which affords light is produced from coal, another gas (hydrogen) is also formed and mixed with it in a large proportion, which, on being ignited, occasions great, heat without adding to the light; these effects render coal gas unpleasant in sitting rooms, and have nearly confined its use to open shops and street lamps.

"It is generally found that the sulphuretted hydrogen which is often mixed with coal gas very rapidly destroys and stops up the smaller pipes which are used for its conveyance; and much in