A Practical Treatise on Gas-light / Exhibiting a Summary Description of the Apparatus and Machinery Best Calculated for Illuminating Streets, Houses, and Manufactories, with Carburetted Hydrogen, or Coal-Gas, with Remarks on the Utility, Safety, and General Nature of this new Branch of Civil Economy.

by Friedrich Christian Accum

Mr. Walker further observes, that it is these sudden changes, and not the nature of candle-light itself, that do so much injury to the eye of the student and artist; and that that injury may be easily prevented, by laying aside the snuffers, and in the place of one large candle, let two small ones be used in the manner stated.

The following observations on this subject are copied from the Monthly Magazine, 1805, p. 206.

“It is scarcely necessary to observe, that the combustion of candles proceeds the quicker in proportion as the inclination is greater. From the experiments which I have made, I should consider an angle of forty degrees with the perpendicular as the maximum of inclination, beyond which several considerable inconveniencies would occur; and I should take 25 degrees as the minimum of inclination, less than which does not sufficiently expose the point of the wick to the action of the air.

“By those who are much in the habit of reading or writing by candle-light, it will also be esteemed no inconsiderable addition to the advantages already mentioned, that the trouble of seeking and applying the snuffers is superseded. A candle of common size in a vertical position, requires the application of the snuffers forty-five times during its complete consumption.

“But I found an obstacle to the adoption of Mr. Walker’s plan, which, from the inclined position of the candle, it did not immediately occur to me by what means to counteract. Any agitation of the air of the room, occasioned either by the opening or shutting of a door, or by the quick passage of a person near the candle, caused the melted tallow to run over, or, in more familiar language, caused the candle to gutter; which, with the candle in this position, became an insuperable bar to the use of it.

“For the prevention of this inconvenience, I have had a wire skeleton-shade adapted to a rod bearing the same inclination as the candle, and which at bottom joins the candlestick in an horizontal line of about two inches, terminating in a nozzle fitting that of the candlestick.—The distance of this rod from the candlestick, or, which is the same thing, the length of the foot or horizontal line, is of course to be determined by the distance between the two circles which form the upper and lower apertures of the shade.—It may serve, perhaps, more familiarly to describe this part of the apparatus, to state, that it bears a perfect resemblance to the two first strokes of the written figure 4; and the third stroke, if carried up as high as the first, and made sloping instead of upright, will very well represent the situation of the candle.

“When a strong light, for the purposes of reading or writing, be required, a white silk or paper may be used, as is common, over the skeleton; but when it be required that the light should be dispersed over the room, a glass of a similar shape may be adopted, for the purpose of preventing the flame from being influenced by any agitation of the air of the room. If the upper circle of the shade be four inches in diameter, the apex of the flame will be within it during more than half the time of the complete consumption of the candle; the shade will not, therefore, require adjusting for the purpose of preventing injury to the silk, or whatever else may be used over the skeleton, more than once during that time.

“Being myself much averse to the interruptions which a candle used in a vertical position occasions, and which, though short, may, under some circumstances, be highly vexatious, I wish to extend to others a benefit which I prize rather highly.”

Lord Stanhope[9] has published a simple method of manufacturing candles, which, according to his Lordship’s statement, is superior to the method usually employed. The principles upon which the process depends are the following:—First, the wick of the candle is to have only three-fourths of the usual number of cotton threads, if the candle be of wax or spermaceti; and only two-thirds of the usual number, if the candle be of tallow. Secondly, it is required that the wick in all cases be perfectly free from moisture, a circumstance seldom attended to in the manufacturing of candles; and thirdly, to deprive the wick of wax candles, of all the air which is entangled in its fibres, and this may conveniently be done, by boiling it in melted wax, till no more air bubbles, or froth appear on the surface of the fluid.