cessive 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 interruptions, 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; but I have preferred giving the results from Messrs. Philips' and Lee's apparatus, both on account of its greater extent, and the greater uniformity of the lights, which rendered the comparison with candles less difficult.

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 volume xli. of the Transactions of the Royal Society, so long ago as the year 1739, gave an account of some observations and experiments made by him, which clearly manifest his knowledge of the inflammable property of the gas, which he denominates "the spirit of coals;" but the idea of applying it as an economical substitute for oils and tallow does not appear to have occurred to this gentleman, and I believe I may, without presuming too much, claim both the first idea of applying, and the first actual application of this gas to œconomical purposes.

XIX. Description of an improved Ship Stove. By Mr. JOSEPH COLLIER, of Crown-Street, Soho, London *. THIS His stove is represented in the engraving Plate IV. Fig. 1. is the stove, with the front partly closed by the circular * From Transactions of the Society for the Encouragement of Arts, Manufac tures, and Commerce, for 1807.-Fifteen guineas were voted to Mr. Collier for this improvement, and a model is placed in the Society's repository. slide

H 4

inconvenience and danger, resulting from the sparks and frequent snuffing of candles, is a circumstance of material importance, as tending to diminish the hazard of fire, to which cotton mills are known to be much exposed.

The above particulars, it is conceived, contain such information, as may tend to illustrate the general advantages attending the use of the gas light; but nevertheless the Royal Society may perhaps not deem it uninteresting to be apprized of the circumstances which originally gave rise in my mind to its application, as an economical substitute for oils and tallow.

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 the gases produced by 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.

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 inter mediate points, was burned through apertures of vari forms and dimensions. The experiments were made u coal of different qualities, which I p parts of the kingdom, for the purpo would give the most economical r washed with water, and other m rify it.

slide A, which is moved from the back by the brass handle B. C a moveable plate attached to the slide A, now supported by the latch catching a pin, by which means it acts as a blower to cause the fire to burn more briskly, but which slides down also to shut the fire up.

D another plate, now hanging on its latch, but which can be let down to shut up the ash-pit or dish I, which can be drawn out when the side facings FF are pulled up. Ga circular plate or cap, which slides so as to shut the chimney up close.

Fig. 2. The body of the stove with the slider A moved round to the back, and thus leaving the fire-place completely open.

Fig. 3. The ash-dish shown separate.

Fig. 4. One of the side facings taken out to show the figure H, which slides into a hole made in the corner of the stove to hold it.

The expense of one of these stoves of twelve inches diameter is about eight pounds.

XX. Method of preparing and applying a Composition for Painting in Imitation of the Ancient Grecian Manner, called Encaustic Painting. By Mrs. HOOKER, of Rottingdean, near Brighton*.

PUT into a glazed earthen vessel four ounces and a half of gum arabic, and eight ounces (or half a pint wine measure) of cold spring water; when the gum is dissolved, stir in seven ounces of gum-mastich, which has been washed, dried, picked, and beaten fine. Set the earthen vessel containing the gum-water, and gum-mastich, over a slow fire, continually stirring and beating them hard with a spoon, in order to dissolve the gum-mastich: when sufficiently boiled, it will no longer appear transparent, but will become opaque, and stiff, like a paste. As soon as this is the case, and that the gum-water and mastich are quite boiling, without taking them off the fire, add five ounces of white wax, broken into

From Transactions of the Society for the Encouragement of Arts, Manufac tures, and Commerce, for 1807.

small

small pieces, stirring and beating the different ingredients together, till the wax is perfectly melted and has boiled. Then take the composition off the fire, as boiling it longer than necessary would only harden the wax, and prevent its mixing so well afterwards with water. When the composition is taken off the fire, and in the glazed earthen vessel, it should be beaten hard, and whilst hot (but not boiling) mix with it by degrees a pint (wine measure) or sixteen ounces more of cold spring water, then strain the composition, as some dirt will boil out of the gum-mastich, and put it into bottles: the composition, if properly made, should be like a cream, and the colours when mixed with it, as smooth as with oil. The method of using it, is to mix with the composition upon an earthen palette, such colours in powder as are used in painting with oil, and such a quantity of the composition to be mixed with the colours as to render them of the usual consistency of oil colours; then paint with fair water. The colours when mixed with the composition may be laid on either thick or thin, as may best suit your subject, on which account, this composition is very advantageous, where any particular transparency of colouring is required; but in most cases it answers best, if the colours be laid on thick, and they require the same use of the brush, as if painting with body colours, and the same brushes as used in oil painting. The colours if grown dry, when mixed with the composition, may be used by putting a little fair water over them; but it is less trouble to put some water when the colours are' observed to be growing dry. In painting with this composition the colours blend without difficulty when wet, and even when dry the tints may easily be united by means of a brush and a very small quantity of fair water. When the painting is finished, put some white wax into a glazed earthen vessel over a slow fire, and when melted, but not boiling, with a hard brush cover the painting with the wax, and when cold take a moderately hot iron, such as is used for ironing linen, and so cold as not to hiss, if touched with any thing wet, and draw it lightly over the wax. The painting will appear as if under a cloud till the wax is perfectly cold, as also, whatever the

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