“The gas-burners made use of in our manufactory produce jets of flame, which in our business, where much soldering with the blow-pipe must be done, have a decided superiority over Argand’s lamps. We are not nice concerning the quality of the gas—a great part of it is burned from the gasometer, without allowing it to purify itself in the gasometer, because our gasometer is not large enough to store up the whole quantity of gas we want for use.”

THEORY
OF
THE PRODUCTION OF GAS-LIGHT,
AND
DESCRIPTION
OF
A PORTABLE APPARATUS
FOR EXHIBITING, IN THE SMALL WAY, THE GENERAL
NATURE OF THIS SPECIES OF LIGHT.

To obtain carburetted hidrogen, or coal-gas, from common pit-coal, and to apply it for the purposes of illumination, the coal is introduced into large iron cylinders, called retorts, to the apertures of which iron pipes are adapted, terminating in a vessel, or vessels, destined to purify and collect the gas. The retorts charged with coals and made air-tight, are placed upon the fire, the action of which extricates the gazeous products from the coals, together with an aqueous ammoniacal vapour, and a tenaceous bituminous fluid, or tar, &c. The liquid substances are conveyed into proper vessels, and the gazeous products are conducted, by means of pipes, under the gasometer, where the gas is again washed, and remains ready for use. There are also other pipes leading from the gasometer, which branch out into smaller ramifications, until they terminate at the places where the lights are wanted. The extremities of the pipes have small apertures, out of which the gas issues, and the streams of gas being lighted at those apertures burn with a clear and steady flame as long as the supply of gas continues. All the pipes which come from the gasometer are furnished at their extremities with stop-cocks to regulate the admission of the gas. The burners are formed in various ways, either a tube ending with a simple orifice, at which the gas issues in a stream, and if once lighted will continue to burn with the most steady and regular light imaginable, as long as the gas is supplied; or two concentric tubes of brass, or sheet-iron, are placed at a distance of a small fraction of an inch from each other, and closed at the bottom. The gas which enters between these cylinders, when lighted, forms an Argand lamp, which is supplied by an internal and external current of air in the usual manner. Or the two concentric tubes are closed at the top with a ring having small perforations, out of which the gas alone can issue, thus forming small distinct streams of light.

[Larger image] (279 kB)

The gas-apparatus, [plate 2], will be found very convenient for exhibiting, in the small way, the general nature of this new art of illumination, whilst at the same time it may serve to ascertain, at a trifling expence, the comparative value of different kinds of coals intended to be employed for the production of this species of light, as well as other occasional purposes connected with the gas-light system of illumination.

It consists of three distinct apparatus:—namely, a portable furnace, [fig. 1, plate 2], by means of which the gas is prepared—[fig. 2], a purifyer, or condenser, which separates and purifies the products obtained from the coal, so as to render the gas fit for the purpose of illumination—[fig. 3], a gasometer, or reservoir for receiving and preserving the purified stock of gas, and from which it may be transferred and distributed as occasion may require. The following statement will explain more fully the general nature of this portable chamber apparatus:—a, represents a cast iron retort, such as is used for chemical operations in the small way. This retort rests upon a tripod of hammered iron, placed upon the bars of the grate of the chemical furnace. Into this retort the coals are put for furnishing the gas. It is provided with a solid iron stopper ground air-tight into the mouth of the retort, and the stopper is secured in its place by an iron wedge passing over it in the centre; by means of which the mouth of the retort when charged with coal is readily made air-tight, and the stopper may easily be removed by knocking out the iron wedge. b. is a metal pipe which conveys all the distillatory products from the retort into the purifier [fig. 2]. This tube is bent at right angles at the extremity where it enters the intermediate vessel [fig. 2]. The purifier [fig. 2], is divided into three compartments marked c. d. e. The first compartment is filled with water, and by means of it an air-tight communication is established with the retort which furnishes the gas. The second compartment, d, contains a solution of caustic pot-ash composed of about 2 parts of caustic pot-ash and 16 of water, or a mixture of quick-lime and water of the consistence of very thin cream. The object of this compartment is to separate the non-inflammable gases and other products evolved during the distillation of the coal, from the carburetted hidrogen or coal-gas, so as to render it fit for use. The third compartment e is left empty to receive the tar and other liquid products. Into the first compartment c, all the gazeous and liquid products are delivered, as they become evolved during the distillation, by means of the pipe b. The compartment d, of the purifier, or alcali vessel, is furnished with a wide perpendicular pipe, which serves to make an air-tight communication with the retort, by allowing the tube b, to pass readily through it. From the chamber c, the liquid and gazeous products pass to the tar-chamber, or compartment e, by means of the descending pipe f. The tar and other condensible substances are therefore deposited at e, whilst the gazeous products alone ascend from the tar-chamber e, by the pipe g, and down again the pipe h, (which is closed at the top) into the compartment d, of the vessel or purifier, [fig. 2]. The gas being thus made to pass from the compartment e, up into the pipe g, and down the pipe h, (which is closed at the top) into the purifier d, is brought into contact with the liquor in that vessel, where it is opposed to a pressure in proportion to the perpendicular height of the column of liquid which it contains. The funnel in the compartment c, is considerably higher than the purifying apparatus, it therefore allows the liquid which it contains, when pressed upon by the gas, to ascend into it, without overflowing the apparatus, and to descend again as the pressure diminishes—i is another wide-mouth funnel, by means of which the chamber d, is filled with the alcaline solution, or mixture of lime and water. The carbonic acid gas and sulphuretted hidrogen, evolved during the distillation of the coal, are thus made to combine with the alcali or lime, in the compartment d, of the purifier, forming carbonate and hidro-sulphuret of lime. The carburetted hidrogen, being left more or less pure, is conveyed through the pipe k, into the gasometer, [fig. 3]. The communication of the purifier, [fig. 2], with the gasometer, is made by means of the well-known water-valve l, placed so that the communicating tube k, may be easily removed at pleasure—m, is a cock for drawing off the tar, &c. n, a gauge-cock for ascertaining the height of the liquid in the chamber d. The gasometer, [fig. 3], the object of which is to store up the gas, consists of two principal parts—namely, a large interior vessel designed to contain the gas, and an outer cistern or vessel, of rather greater capacity, in which the former is suspended, designed to contain the water by which the gas is confined. The interior vessel which contains the gas is suspended by chains or cords hung over pullies, to which weights are attached, so as to nearly equipoise it. o is a pipe, which communicates with the water-valve l, and by means of which the gas passes from the purifier, [fig. 2], into the gasometer. The upper end of this pipe is covered, in the manner of a hood, by a cylindrical vessel p, open at bottom, but partially immersed beneath the surface of the water contained in the outer cistern of the gasometer, and perforated round near the lower edge with a number of small holes. The gas displaces the water from this receiver p, and escapes through the small holes, rising in bubbles through the water, so as to expose a large surface to its action, that it may be properly washed, &c. After rising through the water the gas enters the gasometer, which is suspended to move up and down by the chains, pullies, and balance-weights, q. From the centre of the gasometer a tube, r, descends, which includes a pipe, s, fixed perpendicular from the bottom of the cistern. The fixed pipe r, forms a guide to keep the gasometer always perpendicular. t is also an iron pipe made fast in the centre of the inner vessel, and communicates with the upright tube, s, in the outer vessel. This contrivance obliges the gas to pass into the pipe t, whilst it also serves to keep the gasometer steady when nearly out of the outer cistern.