Observations on Sir W. Congreve's Report on Gas Light Establishments. By M. Ricardo, Esq.

(To the Editor of the Annals of Philosophy.)

Brighton, May 18, 1823.

DEAR SIR, I HAVE been favoured with a copy of the Report of the Royal Society, and two additional Reports of Sir W. Congreve to the Secretary of State of the Home Department, which were laid before the House of Commons, and ordered to be printed, and on which I beg to offer some few observations through the medium of your journal. The first Report, which was signed by some of the leading members of the Society, was made nine years ago (1814), in consequence of an inquiry being instituted to ascertain the probable danger of gas light establishments; the second and third Reports by Sir W. Congreve were delivered in Jan. 1822 and 1823. This gentleman has not confined himself to noticing the dangers which are likely to arise from the diffusion of this mode of lighting, and pointing out what he thinks are the best methods of avoiding them; but he has also entered somewhat fully into the nature and management of the various companies, and has thrown out some hints for legislative enactments to regulate their future conduct, of which I shall take some notice hereafter.

Sir W. Congreve has enriched the Report with some tables of the proceedings of the three principal Companies :-the three stations of the Chartered Company, the City of London Com New Series, Voi, VỊ,

pany, and the South London Company. When I first saw these, I expected to derive some valuable information from them, which would enable me to come to more correct conclusions in my inquiries relative to the comparison between oil and coal gas, but I have been sadly disappointed. A slight examination soon proved to me that the statements which they contain could not be at all depended on, and I was, therefore, led to enter into a more minute analysis of them. I endeavoured, if possible, to account for the very different results which appeared in the different Companies, but with very little satisfaction, as I cannot come to any conclusions that can be relied on. Although this is a subject which I fear will not afford much entertainment to your readers, nor do I think that the private transactions of Companies are fit subjects for public investigation, yet I am induced to send you the result of my inquiries in as concise a form as possible, and chiefly so, as Sir W. Congreve has founded his Reports on these statements, and no doubt relying on their correctness, has thought it necessary to recommend legislative enactments upon them.

In imitation of Sir W. Congreve's plan, I have also annexed a table of the proceedings of the different Companies, part of which is borrowed from his, and the remainder, the results of my own calculations. In the progress of my examination, the observations so accumulated upon me, that I was anxious to devise some mode for putting them in a concise but yet intelligible form, and I saw no better method by which it could be effected than the one I have adopted. Here the whole management of the different works, together with the very different results, may be seen at one view, and any of your readers who, like myself, may be interested in the subject, will be able to form their own judgment as to the probable correctness of the state

ments.

The information which I was chiefly desirous of obtaining, was the quantity of gas that was consumed by a given number of lights, the quantity that was wasted or lost, the capital that is employed, the cost in labour, wear and tear, and management, the profit, &c. but these will be found to vary so much that it will be impossible to come to any correct conclusion.

With regard to the quantity of gas consumed by the different Companies, the mode by which that is estimated in the tables in the Report is so obviously incorrect, that I have adopted another method in order to ascertain it, which, though liable to error, is certainly a nearer approximation than the other. The lights in the Report are divided into two sorts, private lights and public lights; the private lights are stated to burn upon an average throughout the year; that is, for 313 days, excluding Sundays, one with another, four hours per night, consuming, by one Company, 4 cubic feet; another 6, and another 6 feet per hour: the public lights are stated to burn nine hours per night for 365 nights, consuming the same quantity of

gas per hour: now among the public lights are estimated what I have termed occasional lights, such as are used at the theatres, public bodies, churches, meeting houses, &c. which, upon an average, consume a much smaller quantity of gas than the private lights, instead of equalling the public. In the Westminster station, the number of these occasional lights is stated, the private lights being 10,660, the public or street ditto 2,248, and the occasional 3,894. In the other stations, the number of public bodies is given without stating the number of lights. I have, therefore, assumed they are only one half; the whole number, therefore, in the Chartered Company is 21,886 private, 3,452 public, and 5,097 occasional lights, for which a rental is paid of 125,9771. According to the rate of charges, a gas light burning from sunset till nine o'clock, pays 47. per annum. I have estimated in a former paper that this upon an average burns for 20 hours per week, the estimate in the report is four hours per night, or 24 hours per week. This extra allowance will account for those lights which extend beyond nine o'clock, and for which an extra charge is made. The nearest approximation then to an average charge would be for each private light, 41. 4s. The average consumption of each burner where experiments have been tried has always been stated to be 5 feet per hour, and it is upon this quantity and price I have founded my calculation. A private light burning four hours, 5 feet per hour, consumes 20 feet per night, which, multiplied by 313, the number of days, amount to 6,260, which again multiplied by 21,886, the number of lights, will give the whole quantity consumed by the private at 137,006,360 feet, and at 41. 4s. per light, the rental of these will amount to 91,9217. or about 13s. 6d. per 1000 feet.

The public or street lights are I understand usually charged at 51. 5s. each; they are estimated to burn the same quantity as the private lights, and the average time of burning per night throughout the year is nearer ten than nine hours, the nightly consumption of each light then will average 50 feet for 365 nights, and the annual 18,250, which, multiplied by 3,552, the number of street lights, give 64,824,000. At 5l. 5s. per light, the rental of the public lights will amount to 17,981, or about 5s. 9d. per

1000 feet.

The rental then for the private and public lights will amount to 109,902/. which, deducted from the whole rental 125,9777. leaves for occasional lights 16,0751. We may consider that the charge for these lights will be at the same rate as the private lights, or 13s. 6d. per 1000 feet, which would give a consumption for the above-named sum, of 23,814,000 feet. By this mode of calculating, the whole consumption of gas will amount to 225,644,360, leaving a deficiency for waste of 22,499,640, or nearly 10 per cent. I have by the same method estimated the consumption of the City of London Company, and the South London Company.

Those columns marked thus (*), are copied from the tables in the Report; the others are from my own calculations.

My first observations will be directed to the quantity of gas produced and consumed, and here we not only observe a very considerable variation in each Company, but also a very marked difference in the different stations of the same Company. At the Westminster station, it will be found the whole consumption of gas for all lights by my mode of calculating leaves a minus quantity of 5,612,900, which would be considerably more if estimated, as they have done all, as public lights. At the Brick Lane station, the overplus or waste is above 21 per cent.; and in the Curtain Road, nearly 20 per cent. At the City of London Road Works, the waste will be found to be nearly 46 per cent. and at the South London 38 per cent. It will be impossible to account for the extraordinary difference which exists in these statements, but by supposing there must be some error: but the most surprising discrepancy is in the Westminster. The proportion is so different from either of the others, I should be very strongly inclined to think that the quantity of gas produced from a given quantity of coal varied very materially, although it is stated that at each station one chaldron of coals produces 12,000 feet of gas. Unless they have an accurate gas-meter through which all their gas enters as it is made, previous to its passing into the gasometers, I know not by what means they can possibly ascertain what quantity of gas is made, as at times, particularly in the long nights, they must be producing and delivering at the same time; to assume that, because a chaldron of coals has upon one or two trials produced 12,000 feet of gas, it must always produce the same quantity, is certainly a very imperfect datum to calculate upon. At the City of London Works, where it is stated the greatest waste takes place, there are strong grounds for presuming that they over-calculate the quantity of gas produced. By the tables in the Report, a chaldron of coals is stated in all the Companies to yield the same quantity of gas and the same quantity of coke. The Chartered and South London give in addition 10 gallons of tar and 11 gallons of ammoniacal liquor, as it is there termed, while the City of London Works produce 16 gallons of the former, and 18 gallons of the latter. Now it is not very probable that a chaldron of coals in their hands should obtain an excess of 13 gallons of two products without any diminution of the others. The more likely supposition is, that if there be this excess in these, there must be a corresponding deficiency in the other; it is on this account that I have made my calculations upon the quantity of coals used, and not upon the quantity of gas produced. In the one case it is most probable they are correct; while, in the other, their accuracy is more than doubtful. In examining the tables, we are struck with the very great advantages which the Chartered Company possesses over the other two. As we are oftentimes puzzled by the exhibition of a large number of figures, and do not readily see the exact proportions, I have reduced the scale to one