Commons, in 1809, asked the witness: "Do you mean to tell us that it will be possible to have a light without a wick?" "Yes; I do indeed," replied Murdock. "Ah, my friend," replied the member, "you are trying to prove too much."

It was but natural, seeing that oil-lamps and candles were the only The dawn of gas lighting. forms of artificial illumination in use prior to the introduction of gas lighting, that the earliest attempts at illumination by gas should be in imitation of the effects produced by those means. Accordingly we find that one of the first gas-burners employed was the Argand, modelled upon the oil-lamp of that name, which had been found to give superior results; while in more general use, and for some time almost the sole apparatus available, were single jets, giving a flame similar in appearance to that of a common candle, together with various combinations of these jets. A fair idea of the mode of illumination practised during the earliest period of gas lighting may be gleaned from the following extract from a paper describing the lighting of Messrs. Phillips and Lee's cotton-mill at Manchester, read before the Royal Society, in 1808, by Mr. William Murdock:—

Fig. 1.—Early Gas-Burners.
(From Accum's "Treatise on Gas-Lights.")

Nor was much advance made upon these arrangements down to the year 1816, judging from Accum's "Treatise" (before cited), as the subjoined extract from that work, together with the above illustrations, will show:—

It is interesting, in view of the present demand for increased illumination, and for burners of high illuminating power, to note the amount of light produced by the burners then in use. In Mr. Murdock's paper we find it stated that each of the Argands in use at Messrs. Phillips and Lee's establishment gave "a light equal to that of 4 candles (mould candles of 6 to the pound);" and each of the cockspurs "a light equal to 2¼ of the same candles." From which meagre results we conclude that, besides being burnt in an ignorant and wasteful manner, the gas consumed was wofully deficient in illuminating power.

THE BATSWING BURNER.

Who invented the batswing burner? A notable advance was made when the batswing burner was invented. To whom we are indebted for this invention seems involved in some doubt. Although Clegg, in the historical introduction to his valuable work,[2] says, very distinctly, that "the batswing burner was introduced by a Mr. Stone, an intelligent workman employed by Mr. Winsor," it is not so much as mentioned by Accum, even in the third edition of his "Treatise;" and Accum, it may be remarked, was for some time closely associated with Winsor in the promotion of the latter's ambitious and visionary schemes. Yet, if Clegg's statement be correct, it would almost appear to fix the date of the introduction of this burner as prior to 1816. But to whomsoever is due the credit of its invention, certain is it that the batswing burner was a considerable improvement upon the old cockspur. Producing a better light for the gas consumed, it assisted to demonstrate still further the superiority of gas lighting over other methods of illumination; and as it could be supplied at a trifling cost, and contained no delicately adjusted nor easily injured parts, it enabled the benefits of the new method of lighting to be extended to wherever artificial light was required.

Fig. 2.—Batswing Burner.

From the cockspur and single jet burners the gas ascended in streams, Superiority of the batswing over the cockspur burner. rising into the air until it came in contact with sufficient oxygen to completely consume it. In order that this might take place without producing a flame of an inordinate length, and without much smoke, the orifices were restricted to a very small size; and the gas issuing from these at considerable pressure tended to draw in, and mix with the air in its course. Besides the loss of illuminating power caused by this mixture of air with the gas flame (similar to what takes place in a Bunsen burner), the cooling influence upon the small body of flame of the mass of metal composing the burner, operated still further to reduce the quantity of light which the gas was calculated to yield. With the batswing the gas was spread out producing, when ignited, a thin sheet of flame, by which means the gas was enabled to combine more readily with the air necessary to effect complete combustion. The size of the flame being, in comparison with that of the cockspur, so much larger proportionately to the metal burner, the cooling effect of the latter was not so apparent. The increased size of flame, also, of itself, tended to improve the illuminating power; each portion of flame contributing to elevate and sustain the temperature of the whole, and so to heighten the intensity of incandescence to which the light-giving particles were raised.

Even with the Argands of that day, the batswing compared not unfavourably. The former burner, having the regulation of its air supply under complete control, gives the best results when the gas is Batswing and Argand burners compared. supplied to it at a low pressure; as then the requisite quantity of air to ensure complete combustion of the gas can be delicately adjusted by means of a chimney of suitable length. When the gas and air have been nicely adjusted to each other, the flame becomes extremely sensitive to any change of pressure in the gas supply; a diminution of the supply, by reducing the quantity of gas issuing from the burner without at the same time proportionately diminishing the supply of air, tends to destroy the illuminating power by the cooling action of the surplus air; while an increased pressure, by allowing more gas to issue than the air can consume, causes the flame to smoke. But at the time to which I now refer the principles of combustion were little understood, still less applied in the construction of burners. Besides this, the pressure of the gas in the mains was excessive; and there being no method