cular apertures or perforations, of about a thirtieth of an inch in diameter, one at the point of the cone, and two lateral ones, through which the gas issues, forming three divergent jets of flame, somewhat like a fleur de lis. The shape and general appearance of this tube, has procured it, among the workmen, the name of the cockspur burner.

"The number of burners employed in all the buildings, amounts to 271 Argand, and 653 cockspurs, each of the former giving a light equal to that of four candles of the description abovementioned; and at each of the latter a light equal to two and a quarter of the same candles; making, therefore, the total of the gas light a little more than equal to that of 2,500 candles, six to the pound. When thus regulated, the whole of the above burners require an hourly supply of 1250 cubic feet of the gas produced from cannel coal; the superior quality and quantity of the gas produced from that material having given it a decided preference in this situation over every other coal, notwithstanding its higher price.

"The time during which the gas light is used may, upon an average of the whole year, be stated at two hours per day out of twenty-four hours. In some mills, where there is over-work, · it will be three hours; and in the few where

night-work is still continued, nearly twelve hours. But taking two hours per day as the common average throughout the year, the consumption in Messrs Phillips and Lee's mill will be 1250 × 2

2500 cubic feet of gas per day; to produce

which, 7 cwt. of cannel coal is required in the retort. The price of the best Wigan cannel coal, (the sort used,) is thirteen-pence halfpenny per hundred weight, (twenty-two shillings and sixpence per ton,) delivered at the mill, or say about eight shillings for the 7 cwt. Multiplying by the number of working days in a year, (313,) the annual consumption of coal will be one hundred and ten tons, and its cost one hundred and twenty-five pounds.

"About one third of the above quantity, or say forty tons of good common coal, value ten shillings per ton, is required for fuel to heat the retorts, the annual amount of which is twenty pounds.

"The 110 tons of cannel coal, when distilled, produce about seventy tons of good coke, which is sold upon the spot at 1s. 4d. per cwt., and will therefore amount annually to the sum of ninetythree pounds.

"The quantity of tar produced from each ton of cannel coal, is from eleven to twelve ale gallons, making a total annual produce of about twelve

hundred and fifty ale gallons, which not having been sold, its value cannot yet be determined.

1 A

"The interest of the capital expended in the necessary apparatus and buildings, together with what is considered as an ample allowance for wear and tear, is stated by Mr. Lee at about five hundred and fifty pounds per annum, in which some allowance is made for this apparatus being made upon a scale adequate to the supply of a still greater quantity of light than he has occasion to make use of.

"Mr. Lee is of opinion, that the cost of attendance upon candles would be as much, if not more, than upon the gas apparatus; so that in forming the comparison, nothing need be stathat score on either side.

ted upon

"The economical statement for one year, then, stands thus:

“Cost of 110 tons of cannel coal .

Ditto of 40 tons of common ditto to carbonize

Deduct the value of 70 tons of coke.

The annual expenditure in coal, after deducting the value of the coke, and without allowing any

And the interest of capital sunk, and wear and

tear of apparatus

Making the total expense of the gas apparatus,}

per annum, about

D

52

550

600

"That of candles to give the same light, would be about 2000. For, each candle consuming at the rate of four-tenths of an ounce of tallow. per hour, the 2500 candles, burning upon an average of the year two hours per day, would, at one shilling per pound, the present price, amount to nearly the sum of money above-mentioned.

"If the comparison were made upon an average of three hours per day, as in most cases would perhaps be nearer to the truth, and the wear and tear remaining nearly the same as in the former case, the whole costs would not exceed six hundred and fifty pounds, while that of the tallow would be three thousand."

Such is Mr. Murdoch's plain, modest, clear, and methodical statement; and it must be allowed that it afforded very cogent evidence of the superior economy of burning coal gas to procure light in preference to lamps or candles. Subsequent experience confirmed the correctness of his calculations; and the consequences of this publication were important, because the account furnished a criterion for estimating the advantages of Gaslighting.*

* When Mr. Lee was examined before a committee of the House of Commons, in May, 1809, he stated, that the first apparatus he ever saw for lighting by means of gas was about the year 1804; it was a small experiment made at his own house,

But it will be observed that, though his representations appear to be generally favourable, they were very far below the "wonderful" statements of Mr. Winsor, who had boldly asserted that his would "stand the test of the best calculators and chemists." The unembellished detail of Mr. Murdoch is intelligible, instructive, and satisfactory; while, on the contrary, no one can now read Mr.

to determine whether it was applicable to the mills, and he lighted the house first to try if it was wholesome. As the experiment succeeded, in 1805 he ordered, from Messrs Bolton and Watt, an apparatus for lighting the cotton-mills, which was in part put up in 1806, and completed in 1807, and perfectly answered its intended purposes. The cost of the apparatus was between five and six thousand pounds. In the course of his evidence he gave a very minute account of the methods that were used to ascertain the illuminating power of the gas, as compared with candles, in order to determine their respective cost. He stated, as the result of the experiments, that the light produced by a candle of six in the pound required one hundred and seventy-five grains of tallow in an hour, and that half a cubic foot of gas produces the same quantity of light in the same time, and, consequently, from this fact was deduced the comparative cost of each. He also gave many other interesting particulars, which tend to illustrate and confirm the statements of Mr. Murdoch, as well as to evince the accuracy of his observation. They also shew to how great a degree of perfection Mr. Murdoch had attained at this period in the art of Gaslighting, and his great superiority to Mr. Winsor.