Page:Repository of Arts, Series 1, Volume 01, 1809, January-June.djvu/113

disadvantage to be set against them, although I have tried this improved method for several months.

The three principles upon which the new candles are to be made, are the following: First, the new wick has only three quarters 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, the wick must, in all cases, be perfectly free from damp, which essential circumstance is frequently not attended to. And, thirdly, with respect to the manufacture of wax-candles, the wick must be previously prepared by being kept in melted wax till it has lost all the common air that it contained: whilst that operation is performing on the wick, the melted wax appears to be full of froth.

If this plan should become general, we should no longer be in danger of running short of the raw material; but, at all events, the individuals who adopt it, will receive the benefit above-mentioned.

I am, Sir,
Your obedient servant,
Stanhope.

The following table will enable any person who is willing to try the candles manufactured upon Lord Stanhope’s plan, to ascertain the real value of the improvements suggested by his lordship. It shews the result of experiments, to ascertain the expence of burning chamber oil in lamps with wicks of various sizes.

A taper lamp, withe eight threads of cotton, will consume in one hour 325/1000 oz. of spermaceti oil: at six shillings per gallon, the expence of burning twelve hours is 13.71 farthings.

At seven shillings, it is 15.995 farthings.

At eight shillings, it is 18.280 farthings.

N. B. This gives as good a light as the candles of eight and ten in the pound. This lamp seldom wants snuffing, and casts a steady and strong light.

A taper, chamber, or watch lamp, with four ordinary threads of cotton in the wick, consumes 1.664 oz. of spermaceti oil in one hour: the oil at seven shillings per gallon, the expence of burning twelve hours, 7.02 farthings.

At eight shillings, it is 8.022 farthings.

At nine shillings, it is 9.024 farthings.

Experiments to determine the real and comparative expence of burning candles of different sorts and sizes.

A small wick. A large wick. With wax’d wick

Number of candles in one pound. Weight of one candle. The time one candle lasted. The time that one pound will last. The expence in twelve hours when candles are at 12s. per dozen, which also shews the proportion of the expence at any price, per dozen.

18¾ 19 16½ 12 10¾ 7¾ 8 5¾ Mould candles. 5⅞ 4 3

Oz. Dr. 0 14 0 13½ 0 15½ 1 5¾ 1 8 2 1 2 0 2 13 Each. 2 12 4 0 5 2¾

Hr. Min. 3 15 2 40 2 40 3 27 3 36 4 9 4 15 5 19

7 20 9 3 17 30

Hr. Min. 59 26 50 34 44 2 41 24 38 24 21 12 34 0 30 15

42 39 36 20 52 30

Farthings and hundredth parts. 9.70 11.40 13.08 13.92 15.00 17.88 16.94 19.06 Moulds at 14d. per dozen. 15.74 18.56 16.825

The time each candle lasted, was taken from an average of several trials on each size.