Compton Street, Soho.

The extraordinarily rapid progress which the recent invention of lighting with coal gas has made in this country, is perhaps without a parallel in the history of the useful arts.

It was an invention not exempted from the misfortune common to all innovations on established practises, of encountering opposition, but it had the fortune common to few, of obtaining an almost instantaneous triumph.

A single exhibition of the gas lights in actual use was sufficient to determine the public judgment in favour of the new mode of illumination; to see was in this case, indeed to believe.

The legislature responsive to the popular voice, and fortified in its responsibility, by the results of special enquiries which were ordered to be made into the merits of the invention, and in which I had the good fortune to be professionally engaged, gave the most liberal and decided encouragement to its adoption.

Capital, often wanting even in this opulent country for undertakings of magnitude, came to the promotion of the new art of procuring and distributing light in overflowing abundance; and already ere many years are elapsed, such has been the rapidity with which the gas light illumination has advanced, that there is not a city and scarcely a town of any note in Great Britain, in which the art of lighting by means of gas, has not been carried into effect, or in which active measures are not in progress, to participate in the benefit of this important discovery.

When the art was yet in its infancy, I published a Treatise, containing a description of the apparatus and machinery best calculated for illuminating streets, houses, and public buildings, by means of coal gas, with remarks on the utility, safety, and general nature of this new branch of domestic economy, as far as then understood, and practised in the metropolis.

The universal avidity for information on the subject, more perhaps than any particular merit in the work itself, produced a demand in this country for four large impressions of this work, in the course of a few years, and I have also had the satisfaction of finding that the Treatise has been translated into the French, German, and Italian languages.

Since this work was written, however, the art of manufacturing and applying coal gas, has undergone so many material improvements, all combining to bring it to a degree of simplicity, precision, and economy, far surpassing every thing which the original mode of practice exhibited, that I have felt I should be guilty of an injustice to the constant demand which still exists for my former Treatise, had I not made it my duty to publish the work I now present to the reader; superseding altogether the former publication, but superseding it from circumstances of necessity, and with a view to good, which I trust will be found not illusory.

The present treatise, as its title expresses, is intended to exhibit the superior process of manufacturing coal gas now employed in the metropolis and the provincial towns of Great Britain, and to lay before the reader the elevations, sections, and plans of the improved Gas Light machinery, which has stood the test of practice, and is now in action at the most celebrated Gas Light Establishments.

In the first and second part of the Treatise, I have, as introductory to the rest, given a sketch of the chemical theory and production of Gas Light. I have pointed out the leading objects of public and private utility, to which the art of lighting with gas has been, or remains to be applied: and added such other facts and observations as may serve to remove all doubt in the minds of the reader as to the important benefit which this country in particular, and the world at large, have gained by this discovery.

In the third part I have stated the maximum quantities of gas obtainable in the large way, from different kinds of coal.

In the fourth part, I have given a description of all the various forms and dimensions which the distillatory vessels or retorts have successively assumed, as well as of the improvements that have been made in the mode of setting the retorts, with a view to saving them from undue deterioration, and preventing any improvident waste of fuel. I have here given a particular account of the distillatory apparatus now used at the most celebrated gas works in the metropolis.

The fifth and sixth parts, lead the reader considerably further into a knowledge of the economy and practice of this art. They contain an account of a great variety of experiments which have been pursued on a large scale, in order to ascertain the most profitable mode of employing the retorts, the differences of opinion which have existed among practical men with respect to the degree of temperature fittest to be applied, and the number of hours at a time during which the retorts may most advantageously be kept in action, with the particular results which the experiments instituted into these points have afforded; and such other data, as will enable the reader to adopt that mode of operation, which under every circumstance of locality will be found most advantageous.

The changes which have taken place with respect to the retorts, have been before detailed in part fourth; but in order to give the manufacturer a nearer insight into the superior advantages attending retorts of the construction lately brought into use, I have given in part seventh, a detailed description of the horizontal rotary retorts, the application of which has led to a more economical, expeditious, and easy method of manufacturing coal gas than heretofore practised. I have distinctly pointed out the advantages which these retorts present, the particular results they afford, and the method of applying them.

The purification of coal gas forms the subject of part eighth. I have compared here, the apparatus for purifying coal gas, as it was originally constructed, with the improved machinery lately adopted, showing the inefficacy and defects of the former, and the decided superiority which belongs to the latter.

The ninth part gives an account of the various improved gas holders which have been invented, and now are in action at the most recent establishments, for the purpose of storing large quantities of gas. The improvements that have been made in this department of the Gas Light machinery, are particularly valuable and have contributed more perhaps than any other, to lessen the expence of manufacturing gas for commercial purposes.

In the tenth part, I have given a description of an entirely new machine, called the gas-metre, or self-acting guage, lately adopted at the Birmingham, Chester, and other gas works, which measures and registers the quantity of gas manufactured in any given time, from any given quantity of coal, or consumed during any period, by any number of burners or lamps. The great services which such a machine must render both to the manufacturer and consumer of gas, are particularly pointed out, and illustrated to the manufacturer, by serving as a complete check on his workmen as to the quantity of work that ought to be performed, and to the consumer, as an exact measure of the quantity of gas he receives, and ought to pay for.

The eleventh part is appropriated to the description of another apparatus, called the governor, also of recent invention, and now in use at numerous establishments. The design of this machine is, to regulate the pressure of the gas, before it enters into the mains, the importance of which must be sufficiently manifest. I have also pointed out the application of this apparatus for regulating the magnitude of the flames of gas burners and lamps.

The twelfth part treats on gas mains and branch pipes, I have here stated the rules and practical proceedings necessary to be observed, for applying and distributing gas pipes to the greatest advantage.

The most efficient method of introducing the gas to the interior of houses, forms the subject of part thirteen. All the necessary instructions are here given to workmen, for adapting the gas pipes, and insuring success at the least cost, under every variety of circumstances.

The fourteenth part gives an account of the illuminating power of coal gas—the quantity of gas consumed in a given time, by different kinds of gas burners and lamps, the relative cost of gas, tallow, and oil lights of different intensities, and the most improved method employed for ventilating apartments lighted by gas.

In the fifteenth and sixteenth parts, I have added an account of the manufacture of carburetted hydrogen gas, from coal tar, vegetable tar, and oil, with such other observations as may enable the reader to form a proper estimate of the comparative advantage of manufacturing gas from oil, or tar, under certain circumstances. I have here also given an account of the manufacture of carbonate of ammonia, as now practised, from the ammoniacal liquor obtained in the Gas Light process, and of the manufacture of other saleable products obtainable from coal, namely; pitch, coal tar, and oil.

In conclusion I have to observe that my object throughout has been to make the work a compendium of all the best information which the practice of the art down to the present moment has been able to afford, embodying a great number of data, with which I have been obligingly favoured by gentlemen, the most practically versant in the art, and for which I beg they will individually accept this public expression of my thanks, and obligations, as well as the results which my own labours in this department, neither few, nor inconsiderable have furnished.

To supply the reader with a work of practical utility in a most valuable, and growing branch of national economy has been my object; and I need scarcely add, that the suffrages of the public to the zeal and industry at least with which I have endeavoured to obtain that object, will be a source of infinite satisfaction.

FREDRICK ACCUM.

LONDON, 1819.