omitted to give facts and calculations to corroborate this statement. His publication contains some useful suggestions, and it is alleged that he has taken out a patent for his scheme. A patent has recently been obtained by a Mr. Daniel, for converting rosin into gas by distilling it with the volatile oil that forms one part of the residuum of oil gas. This method has been adopted at the Portable Gas Works, but of the success which may have attended the project, the knowledge is confined to the few persons who may be engaged in its processes. However, this is the latest attempt to introduce improvement into the operations for making gas. A very simple, but ingenious, apparatus has lately been contrived by Mr. Crosley for the purpose of registering the impurities which may remain in the gas. It consists of a circular card which is placed upon an axis communicating with a time-piece. Three circles are described upon the card, and the circles are divided into twenty-four divisions, by lines drawn from the centre to the circumference, corresponding with the number of hours of day and night, and numbered accordingly. The two largest circles are made of equal breadth, and occupy the outer space of the card; these are covered with a solution of the tests usually employed to detect sulphuretted hydrogen and ammonia; and by means of a pipe which has two orifices adapted to each of the circles, a very small jet of gas is made to play constantly upon the tests. The spaces in the inner circle are marked from one to twelve for day, and one to twelve for night, and as the time-piece moves the card by its revolution, the impurities (if any exist) are registered, and the precise time when they occur. As these cards are to be daily changed, a perpetual account may be kept of the state of the gas.* In the preceding pages an attempt has been made to arrange, as nearly as possible in the order of time, the principal facts and inventions connected with the rise and progress of the art of Gas-lighting. To estimate the many advantages which have resulted from its introduction would, perhaps, be impracticable; for, independently of the pleasantness and utility of its light, it has given a most important impulse to several branches of our national manufactures. The erection and adaptation of the numerous large works for its purposes have furnished employment to a large mass of our industrious population, and, at the same time, they have afforded many incentives to the exercise of ingenuity. But it has benefited the iron trade to an incalculable * For a representation of this instrument, see Compen dium of Gas-Lighting. extent; and it has also occasioned a great consumption of metals of other kinds. Its operations have given rise to a large and flourishing branch of manufacture, by the demand for tubing, burners, and various other articles which that part of its processes has rendered necessary; and it may not be unworthy of remark, that to no part of the nation has it been of more service in this respect than the town of Birmingham and its vicinity, where gas-lighting and its advantages were first publicly displayed. The spirit of enterprise which has marked its career reflects honour on our country; and notwithstanding so much has been effected, the art is probably very far from that perfection which it may attain at some future period. It is fair to presume that the present meritorious endeavours widely to diffuse useful knowledge, will have an appropriate influence upon that class of men who are more immediately engaged in gas operations, and enable them to add to the number of its improvements. And from the continual increase of establishments for gas-lighting, it seems not an improbable supposition that its use, as a medium of light, will ultimately become universal. MR. MURDOCH'S OWN ACCOUNT OF THE ORIGIN AND "It is now nearly sixteen years since, in a course of experiments I was making at Redruth, in Cornwall, upon the quantities and qualities of different kinds of gases, produced by the distillation from different mineral and vegetable substances, I was induced by some observations I had previously made upon the burning of coal, to try the combustible property of the gases produced from it, as well as from peat, wood, and other inflammable substances; and being struck with the great quantities of gas which they afforded, as well as with the brilliancy of the light, and the facility of its production, I instituted several experiments with a view of ascertaining the cost at which it might be obtained, compared with that of equal quantities of light yielded by oils and tallow. 66 My apparatus consisted of an iron retort, with tinned, copper, and iron tubes, through which the gas was conducted to a considerable distance; and there, as well as at intermediate points, was burned through apertures of varied forms and dimensions. The experiments were made upon coal of different qualities, which I procured from distant parts of the kingdom, for the purpose of ascertaining which would give the most economical results. The gas was also washed with water, and other means were employed to purify it. "In the year 1798, I removed from Cornwall to Messrs. Boulton, Watt, and Co.'s works for the manufactory of steam-engines at the Soho foundry, and there I constructed an apparatus upon a larger scale, which during many successive nights was applied to the lighting of their principal building, and various new methods were practised of washing and purifying the gas. "These experiments were continued with some interruption until the peace of 1802, when a public display of this light was made by me in the illumination of Mr. Boulton's manufactory at Soho upon that occasion. "Since that period I have, under the sanction of Messrs. Boulton, Watt, and Co., extended the apparatus at Soho foundry, so as to give light to all the principal shops, where it is in regular use, to the exclusion of other artificial light. "At the time I commenced my experiments, I was certainly unacquainted with the circumstance of the gas from coal having been observed by others to be capable of combustion; but I am since informed that the current of gas escaping from Lord Dundonald's tar-ovens had been frequently fired; and I find that Dr. Clayton, in a paper in Vol. XLI. of Transactions of the Royal Society, so long ago as the year 1739, gave an account of some observations |