sire of vindicating a father's fame has hada principal share in making an author of the son, Mr. Peckston may read in this fact a valuable lesson on the advantage, in the long run, of even-handed justice.

But the "Practical Treatise" of Mr. Clegg, jun. (for, as if more peremptorily to challenge comparison, he adopts the same title as Mr. Peckston) is no family affair. There is, in truth, much less of the son in the one book, than there is of the brother-in-law in the other. To write a complete and true history of the rise and progress of the gas-light manufacture, without making more frequent and prominent mention of Mr. Clegg than any other person, is, for the reasons before stated, impossible; and such a history is simply what Mr. Clegg, jun., has achieved, with far less indulgence in language of praise towards the chief actor in it, than might have been expected, and would readily have been excused. Anxiety to place the services of a near relation fairly before the public, has not prevented him from doing everywhere full justice to the claims of others. He has enjoyed, he tells us, "access to, and the free use of, his father's manuscripts and notesthe result of his long labours and experience in this department of engineering;" and so far he has had greatly the advantage over Mr. Peckston and every other writer on the subject.

Mr.

Mr.

Peckston's experience dates no farther back than about twenty years, but that of Mr. Clegg, sen., embraces twice twenty years-goes back, in fact, to the very origin of lighting by gas. Clegg, jun., has brought, besides, to the execution of his task, talents and attainments of his own of no mean order; some considerable experience, too, acquired under the immediate eye and fostering care of the Nestor of the art; and of these personal qualifications the volume before us exhibits many pleasing proofs.

The early history of gas-lighting is related much in the same way in both Treatises; and is, in its general features, familiar to most readers. The following incidents, which we quote from the Clegg treatise, we do not remember to to have met with before :

SIR HUMPHREY DAVY ON GASOMETERS.

"The great prejudice entertained against the introduction of gas-lighting, not only by

the public, but also by men of science, seemed at one time to present an insurmountable obstacle to its further progress. Lighting a town with gas was still thought a visionary scheme. Sir Humphrey Davy considered the idea so ridiculous, that he asked "if it were intended to take the dome of St. Paul's for a gasometer? to which Mr. Clegg replied, that he hoped to see the day when gasometers would not be much less. They are now (1841) made 100 feet diameter, and 39 feet deep."

ROYAL SOCIETY SCIENCE AND WISDOM.

"After the works at Peter-street had been some time in operation, Sir Joseph Banks and several other members of the Royal Society were deputed to examine and report upon the gas apparatus. The deputation strongly recommended Government to oblige the Company to employ gasometers em. bracing not more than 6,000 cubic feet, secured in strong buildings. As Sir Joseph Banks, and some of the other members of the deputation were considering on the danger of a leak in the gasometer if a light happened to be near, Mr. Clegg called to a man, desiring him to bring a pick-ate and candle; he then struck a hole in the side of the vessel, and applied the light to the issuing gas, to the no small alarm of all present, most of whom quickly retreated; contrary to their expectation, no explosion resulted from the experiment. This practical proof, however, did not seem to convince them of their error, and the Chartered Gas Company was put to considerable expense in making small gasometers surrounded by strong buildings."

DIFFICULTIES IN PUSHING A NEW TRADE.

"The Chartered Gas Company at first fitted up and supplied shops and houses with gas free of expense, in order to induce others to adopt the plan; so things went on for nearly two years, with only a few retorts in action.

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*

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the Peace of 1814, when the Allied Sovereigns visited England, the devices in gas lights far exceeded in splendour anything before or since exhibited; the principal illumination was a pagoda, erected by order of government in St. James's park. This pagoda was octagonal, composed of wood, eighty feet high, at each angle of which a perforated pipe was fixed; a projecting pipe was also placed at every angle of each story, in the form of a griffin's head, pierced with small holes, through which issued jets of gas. At the lowest orifice of each perpendicular pipe a small oil lamp was concealed, which, when lighted, ignited the first jet of gas; this communicated the light to the next jet, and soon to the summit. The burners of each angle were thus simultaneously ignited, and the gas light rose into the air with the majesty of a rocket; and the pagoda illuminated by more than 10,000 burners, was fired in a few seconds, the whole appearing like a mass of living light. This device was fortunately exhibited to the Prince Regent, and most of the royal family, at their request, on the night previous to the general illumination; their highnesses walked in Carlton-gardens to witness the effect, and expressed great approbation. The night on which this first grand display of gas lighting was to have been exhibited to the public, Sir William Congreve, contrary to Mr. Clegg's advice and request, insisted upon letting off fireworks from the pagoda, before the gas should be turned on; the consequence was, that the whole erection was burned to the ground. The accident was not only mortifying, on account of the expense and trouble incurred by the Gas Company in this affair, but still more unfortunate, as gas lighting had only been lately introduced, and all new schemes (as great improvements are generally called) have many enemies. A report was spread abroad the following day, that the gas had set fire to the pagoda; the public was never entirely undeceived."

The advantages of gas lighting, as contrasted with artificial light obtained from other sources, are very fully discussed in both Treatises. Mr. Peckston concludes a long chapter of directions for ascertaining the comparative illuminating power and cost of wax and tallow candles, wick lamps, and gas lamps, with a Table of results, from which it appears that when gas, at 9s. per thousand cubic feet, is burnt to the best advantage, which is in a fifteen hole argand, with a flame three feet in height, the comparison stands as follows:-One gas lamp supplies as much light for 41. 2s. 2d. per annum as would cost 167. if procured from tallow can

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dles at 8d. per pound, or 431. 10s. if from wax, at 2s. 6d., or 157. 15s. if from sperm oil at 9s. per gallon. Mr. Clegg's estimates differ considerably from these, which apparently arises, in the first place, from his making allowance for the increase of illuminating effect consequent on any increase in the specific gravity of the gas-a very necessary element in the calculation, but not taken into account by Mr. Peckston in his Comparative Table, though made the subject of a special notice towards the end of his work, (as if it had been an afterthought;) and, secondly, from his adopting higher rates of cost for the gas, and lower for the contrasted articles than Mr. Peckston has done. Clegg's estimate is that 6,000 cubic feet of coal gas of the specific gravity 400, when supplied with a sufficient volume of oxygen for its complete combustion, is equal to the light from 2,400 candles, eight in the pound; and that the difference in favour of the gas at 12s. the 1,000 cubic feet, (a high rate,) is compared with tallow candles at 64d. per lb., (a low rate,) as 15s. 1d. to 27s. 1d.

Mr.

It seems to be agreed that coal gas cannot be manufactured with economy by means of any apparatus at present known on a small scale. The point of economy does not, however, descend so low but that every town in the kingdom without exception, might be lighted with gas at a profit. Mr. Clegg gives a statement of the outgoings and receipts of a country gas establishment for 64 public and 72 private lamps, which exhibits an annual profit of no less than 1917. 7s. 10d. The inducement to erect such establishments is the greater that there is no variableness in the results-no chance of loss one year to be set off against the profits of another.

"Upon a well-regulated system, the cost of producing every 1,000 cubic feet of gas with the same coal, will not vary one penny the whole year round; the quantity of gas made will be adequate to the demand, and no more. The wear and tear of the machinery will be exactly that which was anticipated, and therefore the annual outlay will be known; the sale of the products of the establishment may be depended upon with equal certainty, and the income, with the profit arising from the difference, is thus obtained."-Clegg.

"The price of coals can exert but little influence upon the price of the gas produced from them, for where coals are plentiful it

follows that they will be cheap, and hence also will be the coke produced therefrom; but where coals are dear, the coke will also sell for a higher price, and find a more ready market."-Peckston.

In the early days of gas-lighting, the quantity of gas obtained from the distillation of a ton of coal did not much exceed 6,000 cubic feet, by the consumption of half a ton of coal for heating the retorts, but so great have been the progressive improvements in this branch of the art, that the product per ton is now seldom less than 9,000 cubic feet, and amounts frequently to much more; while the fuel expended on the carbonization has been reduced from 50 to 25, and in some cases to as low even as 16 per cent. Among these improvements, the principal have been, a reduction in the size of he retorts from 20 inches to 12 and 10 in diameter, so as to admit of the coal being carbonized in thin layers-the substitution for circular retorts, of retorts of a form more or less approaching to the semicircular-and the setting of these retorts, of whatever form in ovens, instead of subjecting them to the direct action of the fire. Mr. Peckston gives the preference to retorts of an elliptical form over all others, and there was a time when he claimed the invention of that form for his friend Mr. Malam, though in his present edition he does not once mention Mr. Malam's name in connexion with it. Mr. Clegg seems to prefer the D-shaped retorts, but not very decidedly, and with a disingenuousness, which is unusual with him (indeed this is almost the only instance of the sort we have observed,) does not once notice the elliptical.

According to Mr. Peckstone, there is a saving of 2,8061. to be realized on the production of 44,598,684 cubic feet of gas per annum by the adoption of elliptical retorts; and this is advantage enough, to entitle the data on which it is founded to the most attentive examination.

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Retorts made of fire-clay instead of iron, have been adopted. Mr. Peckston says they were thought likely to be very durable, and also to produce very extraordinary results; but on being tried they were found neither to possess durability, nor to effect any other advantages over cast iron retorts of the same shape and size:" and with these general observations he dismisses them to the lumber

tise:

"It appears that clay retorts have great power to retain their heat, when brought to the proper temperature for decomposing the coal, viz. 27° of Wedgewood, and the introduction of a fresh charge is not nearly so much felt by them as by metal. This is a practical point-one which I have been at much pains to ascertain, and which I would not state were I not convinced of its correctness by personal observation. Mr. Grafton, the inventor and patentee, afforded me every facility for experiments, and is willing to do so to all who have a desire to test his retorts. This power of retaining heat is proved by constant practice to produce 1,000 cubic feet of gas per ton from the same coal more than the average of the London produce, and the consumption of fuel is not more than 22 or 23lbs. of coke to carbónize 100lbs. of Newcastle coal, taking the average of six months' working; it is even less with the Staffordshire or Lancashire coal. When properly constructed, these retorts are not in any degree liable to fracture, or to the escape of gas, but are of such strength as to resist the greatest pressure which is likely to be put upon them. The coke, also, made by them is also considerably of better quality, and produces less breeze or waste. The advantages of the fire clay retorts, combined with their great durability, will ere long be generally acknowledged and their use will consequently be more extensive."

The gas, after it leaves the retorts, has

to undergo several processes of purification before it is fit for use; of which the most important is the passing it through lime more or less slaked with water, in order to free it from the sulphuretted hydrogen with which it is always largely intermixed, Mr. Peckston states, "that when coal gas was first employed for the purpose of procuring light, it was allowed to proceed to the place where it was intended to be burnt, without undergoing any purifying process other than passing it through water; and it appears that some time elapsed before lime and water were used as a purifying medium." (p. 233.) Mr. Clegg, he elsewhere says,

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put up the first purifier." (p. 93.) We regret to have here again occasion to find fault with Mr. Peckston for grossly offending (from ignorance it can hardly be) against the truth of history. The first gas apparatus ever erected (1805) was that at the cotton mill of Mr. Henry Lodge, of Sowerby Bridge, near Halifax; the second, that of Messrs. Phillips and Lee, of Manchester (1805); the third, one for lighting the private residence of Mr. Lodge (1806); the fourth, Messrs. Knight's, of Longsight (1809); the fifth, Mr. Harris's, of Coventry (1809); and the sixth, that of the Catholic College of Stonyhurst (1811); the whole of which were erected by Mr. Clegg, with the exception of the second, which was erected by Mr. Murdoch, who had, by some previous experiments on a small scale, at the Soho manufactory, demonstrated for the first time the practicability of lighting by gas, and acquired thereby a just title to be regarded throughout all time as the father, or inventor, of gas-light illumination. Now, in the third of these cases, it was attempted to purify the gas by introducing lime into the tank of the gasometer; in the fifth, a paddle was added, to agitate the lime; and in the sixth, the gas was passed through a separate vessel filled with lime water, previous to its entering the gasometer,-the mode of purification which has continued to be followed, with but little variation, to the present day. The "some time," therefore, which Mr. Peckston tells us, "elapsed before lime and water were used," amounts, as nearly as possible, to just no time at all; for Mr. Clegg made use of it in the very second apparatus he ever erected, which was within less than a year of the first; and there were not in all more than two sets

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erected without such an appendage-Mr. Clegg's first, and Mr. Murdoch's first. Nor did Mr. Clegg merely "put up the first purifier," as Mr. Peckston, with most ungenerous stintedness of phrase, relates; he was the true and first inventor of the thing; he instantly perceived that without purification there was to be no progress made in the application of coal gas to purposes of illumination; and almost as instantly, by the resources of his very inventive genius, overcame it.

Mr. Peckston is not, we regret to say, the only individual at whose hands the claims of Mr. Clegg, in respect of this invention, have been unfairly slighted. In 1808, Dr. Henry communicated to the Royal Society a paper, in which he described the application of lime water, on a large scale, for the purification of gas from sulphuretted hydrogen, as a contrivance of his own; though, as we have seen, it had been reduced to practice by Mr. Clegg two years before; and Dr. Henry appears, from circumstances stated by Mr. Clegg, jun., to have been well aware of this fact.

We come now to the invention of the meter, by which the gas, after it has been made fit for consumption, is measured out to the consumers. The long standing dispute between Mr. Clegg and Mr. Malam (or rather Peckston pro Malam) on this subject, is now reduced by admissions on both sides to so narrow a point, that there is happily little left for us to do, beyond recording the agreement at which the disputants have arrived. "Some one may say," quoth Mr. Peckston, "that Mr. Malam only invented the L pipe and receiving chamber; be it so; if that be admitted, the rest follows, for the former completely changed the mode of entrance of the gas into the meter, and removed the great obstacle to the action of such an instrument." p. 367. "The merit," says Mr. Clegg, jun., with admirable candour (under all the circumstances,) "of applying a pipe on one side of the axis to convey the gas into the meter, is due to Mr. Malamdecidedly the most important improvement since its invention." p. 22. Nothing could be more distinct or unreserved than these reciprocal admissions, that Mr. Malam but improved what Mr. Clegg invented; yet it will hardly be believed that, in spite of Mr. Peckston's "be it so," he is not content that it should rest so; for he still persists every

where else in speaking of Mr. Malam as "the inventor of the gas meter," not the improver of it; and in order that a due share of solemnity might not be wanting to crown this intolerable inconsistency, he gravely adds, "we do so under the most perfect conviction that we are correct !""

A word or two before we leave this subject on the conduct observed towards Mr. Clegg and Mr. Malam, by that very sapient and eminently useful and respected body, the Society of Arts. In the summer of 1838, Mr. Clegg sent to that Society an account of his then still novel experiments in gas lighting, and the sages of the Adelphi, in order to testify to all future generations, how sensibly alive they were to the vast importance of the new art-how grateful to its most assiduous and successful, if not earliest cultivator-and how munificently liberal of encouragement to perseverance, awarded to Mr. Clegg their silver medal! But when, fourteen years afterwards, Mr. Malam presented himself to their notice as the inventor of the meter, which it is now established, past all dispute, he only improved-with this feather in his cap, snatched from the plume of his early master and preceptor, (Mr. Malam was originally a draughtsman in Mr. Clegg's office,) the Society, with the same magnanimous regard for the claims of genius, and the interests of science, which they had before displayed-with the same keen solicitude to show how well qualified they were (as every one knows they still are,) to sit in judgment on matters of this high import, awarded to the pretender-pupil for his single borrowed feather, the highest mark of approval in their power to bestow, namely, their gold medal! Who can but wonder that so nice a society as this should ever have fallen into decay?

The "Distribution of gas through Mains" forms the subject of an excellent and most useful chapter in the Clegg Treatise, but it is only very partially treated of in that of Mr. Peckston. It includes a set of "Tables of the different quantities of coal gas of the specific gravity 420, delivered in one hour from horizontal pipes of different diameters and lengths, and under different pressures,' which will be found of great practical value to all gas establishments. It appears to be well ascertained that the quantities of gas of any given specific

gravity, discharged in equal times by horizontal pipes of different lengths, under the same pressure, are to one another in the inverse ratio of the square roots of the lengths; and also that the obstruction to the flow of gas through pipes is very nearly as the number of bendstwo semicircular bends, for example, making twice the difference, three bends three times, and so on.

For regulating the flow of gas at the point of inflammation, both Treatises agree in recommending Platow's double cone burner as the most efficient. "This arrangement causes the light produced to burn steadily, and renders it very soft and agreeable. A saving of gas is effected by its use, amounting to about 10 per cent., whilst the heat generated, thereby is proportionably less than when the common Argand burner is used."— Peckston. "This description of burner is by far the best Argand, and should be universally adopted."-Clegg.

The "Secondary Products" of gas establishments, as coke, coal tar, ammoniacal liquor, naphtha, &c., are more sparingly treated of by both writers, than their importance in an economical point of view demanded. We quote from Mr. Clegg's Treatise the following notice of an application of the naphtha, lately discovered by the ingenious Mr. Lowe, which seems to promise very important results.

Naphthalizing Coal Gas.

"If coal gas is conducted through naphtha before being burned, the light is increased in brilliancy more than 50 per cent. I witnessed an experiment on this at Mr. Lowe's house, a few weeks ago, and certainly the effect was dazzling. The naphtha was contained in a sponge placed in an airtight cap or vase below the burner. Mr. Lowe has also obtained this increase of illuminating power by filling the meter with naphtha, and thus describes his method :

"As it regards the first part of the same, or in

creasing the illuminating power of such coal gas as is usually produced in gas works by impregnating

such gas with naphtha, commonly called spirit of coal tar, or with any other volatile hydro-carbonaceous liquid: the method I adopt for so impregnating the said gas, is by merely filling the case of the common gas meter to the usual height, with any of the said liquids instead of water, by which means the said gas discharged by the meter to the burners is during the operation of measuring, sufficiently impregnated with the said liquid in the meter case."

Neither Mr. Peckston nor Mr. Clegg take the least notice of Mr. Gurney and