unreasonable. The municipal erees, in their Report on the Construction | no means of Gas-burners,' &c., stated their conclu- authorities objected that the burner was too sions as follows: costly for common use, and also that the What a boiler is to coal and the generation flame was very sensitive to draughts; but of steam, so is a burner to gas and the devel- on the other side it was maintained that opment of light. One ton of coal in a loco- the cost of the burner was not greater than motive of the present day generates as much that of the standard burners previously in force as six tons did forty years ago, simply use, and that it was impossible to improve owing to the superior construction of the lo- the light-giving capacity of gas-burners comotive. In like manner, as regards the il-without increasing their delicacy, just as is luminating power of gas, there are good burners and bad ones. Moreover, as every scientifically constructed boiler is devised specially for a given amount of coal, by the consumption of which the boiler develops the maximum of power relative to the quantity of fuel used, so every well-constructed burner is devised to consume a fixed quantity of gas. Indeed, for every burner, whether good or bad, there is a certain rate of consumption at which the burner does more justice to the illuminating power of the gas than at other rates, whether greater or less. To disregard these considerations, is to render experiments wholly useless and misleading. An argand burner is fitted to consume a special quantity of gas of a given quality, just as much as a rifle is specially adapted for a special ball and charge of powder. And the same is true of every kind of gas-burner. First, as to good burners and bad ones. Take two burners, each of which gives its maximum of light (i.e., does more justice to the gas) at the same rate of consumption: nevertheless the light emitted by one of the burners may be much greater or much less than that of the other. Secondly, as to the misuse of burners. Take a burner which does most justice to the gas when the rate of consumption is five feet per hour: then if the rate of consumption be either increased or diminished from that point, the gas will of course give out less light in proportion to the quantity consumed than before. Both of these facts, simple as they are, seem for long never to have been even suspected. the case with most other kinds of appa ratus. But the most important aspect of the question relative to the choice of this standard burner remains to be stated. It was a matter of vital importance to the Gas Companies financially. As already shown, the amount of light obtained from gas varies immensely according to the burner employed; and as the Gas Companies are required under heavy penalties to supply gas of a fixed degree of illuminating power, it was of the utmost importance to them that the burner employed in testing the gas should be such as to yield the utmost possible amount of light from the gas. The new burner thus chosen as the standard entirely satisfied them in this respect, but for the same reason, it did not satisfy the municipal authorities, who complain that an act of jugglery has been practised upon them and likewise upon Parliament. And undoubtedly, as has since been fully acknowledged, this remarkable and unsatisfactory effect has resulted from successive changes in the burners officially employed for testing London gas, that, although during the last twenty years Parliament has raised the illuminating power required of dles to sixteen candles, the actual illuminatthe Gas Companies from that of twelve caning quality of the gas is at present no greater than it used to be previous to 1860. When the Act of 1860 was passed, the immense difference which different kinds of burners make upon the light given by gas had attracted little attention from men of science, and no attention was given to it by Parliament. By that Act Parliament meant to raise the illuminating power of the gas supplied to London to the extent of As the result of their elaborate testings and examinations of all the gas-burners then in use, the referees in the spring of 1869, chose as the standard burner for London gas, to be employed in the official testingstations, a new argand burner invented by Mr. Sugg, of Westminster-a manufacturer who has done more than any other to improve the construction of gas-burners, and whose argands were reported upon by the gas referees as the best of the kind. The standard burner thus fixed by the referees admittedly gives a beautiful white light, and, what is also important, a very steady light, agreeable to the eyesight. But the adoption of this burner as the standard gave rise to much opposition on the part of the municipal authorities; and although it has been approved by successive parliamentary committees, the opposition was byly different results being dependent upon two candles,' and accordingly the Act prescribed that the illuminating quality of the gas should be equal to that of fourteen sperm candles; but the standard burner which Parliament prescribed for the testing was merely described as an argand burner with fifteen holes and a six-inch glass chimney. As has since been found, such a burner may be either a very bad one, or as perfect a burner as can be devised these wide their presence in the gas is not noxious to phur in the gas, because when burnt it pro- the size of the holes and other arrange- | bonic oxide have never been regarded as ments. A few years afterwards (about impurities in Acts of Parliament, and no 1864), Dr. Letheby, in conjunction with penalty has been attached to them, because Mr. Sugg, produced a greatly superior argand of this kind to any previously constructed; and almost simultaneously the Birmingham' argand was produced, giving equally good results with the Sugg Letheby burner. The effect of this improvement was that two candle-power more light was obtained from the same quality of gas-the old twelve-candle gas became fourteen-candle gas-and thus the Gas Companies were enabled to evade the parliamentary requirement, and supplied no better gas than before. In 1868 the continued complaints of the public as to the bad gas,' the poorness of the light which it gave, induced Parliament to make a further increase in the illuminating power, which was thereupon fixed at sixteen candles. But still no attention was given to the importance of the burn-wise been attached to the presence of suler employed in testing-which was as great and as fatal a mistake as if Parliament had required that some article should be supplied to the public at 3s. 9d. the bushel, without stating whether it was to be weighed by the Winchester, or any of the other different bushel-measures. Indeed the mistake was even greater than this; for the difference produced by the common and by the improved burners is much greater than that which exists between any of our weights and measures. But the Companies had become fully alive to the matter. Before the passing of the Act of 1868, Mr. Sugg had devised a new and still better argand, giving two candles more light than the Sugg-plied to the public; and in 1868 the maxiLetheby one-no mention of which was made when the Act of 1868 was under consideration. But as soon as the Act was passed, the new burner was produced, and the gas referees, as already stated, felt themselves bound by the terms of the Act to accept this new burner as the standard. And so it remains and so the remarkable state of matters has been produced that, although Parliament has twice meant to raise the illuminating quality of London gas, and has twice done so as explicitly as it was able to do, first from twelve to fourteen candles, and thereafter to sixteen candles, nevertheless London gas is actually of no better illuminating power at the present day than it was twenty years ago, before Parliament had dealt with the matter at all. Next, as to the Purity under which London gas is required to be supplied by the Companies who enjoy the monopoly. Coalgas contains several impurities, namely, carbonic acid and carbonic oxide, ammonia, and sulphur-acids. Carbonic acid and car Since 1860 Parliament has absolutely prohibited, under penalties, the presence of sulphuretted hydrogen (an easily extractable impurity) in any quantity in the gas sup mum quantity of the two other impurities (viz., ammonia and bisulphide of carbon) to be allowed was to be left to the decision of the gas referees, with an injunction to alter or lower the maxima for these impurities 'from time to time,' as the science of gasmanufacture progressed. The ammonia maximum was fixed by the gas referees at five grains per hundred feet of gas in 1869, and at half that quantity in 1871; but the fixing of a maximum for the other impurity 6 termed in the Gas Acts of 1860 and 1868 sulphur in other forms than sulphuretted hydrogen,' and which is now known to be bisulphide of carbon-gave rise to a great and prolonged difficulty, technically termed the Sulphur Question,' the correspondence and reports upon which subject between the municipal authorities, the Board of Trade, and the gas referees, occupies a parliamentary paper of considerable size. Until about a quarter of a century ago it was not known that any such impurity as this existed in coal-gas, and it was the dele stated in 1870, it came to be doubted whether the sulphur in coal-gas (other than sulphuretted hydrogen) was bisulphide of carbon at all.' The field of inquiry was thus a tabula rasa, and Mr. Patterson, who ultimately solved the problem, began by experimenting with the two component parts of the impurity separately. He found that two entirely opposite kinds of chemical affinity could be brought to bear upon the bisulphide of carbon. By the affinity of similars, or of like to like,' he found that by employing sulphur powder, together with a chemically inert substance, such as sawdust, he could extract two-thirds of the amount of sulphur remaining in purified coal-gas. Then, as bisulphide of carbon is an acidulous body, he employed the ordinary affinity of opposites, or of alkalies for acids, and he found that an alkaline solution, viz., of soda or ammonia, extracted a considerable portion of the sulphur, provided the gas were suitably prepared by the previous extraction of the carbonic acid so largely contained in it. Finally, by a combination of these two processes, he fully achieved his purpose, ascertaining that each and all of the alkaline sulphides will purify coal-gas from the residual sulphur, provided that the gas be previously prepared for such operation by being freed from its other impurities, which being acids would destroy the alkaline sulphides. He also devised a process by which alkaline sulphides could be produced in gas-works, terious action of this impurity which at length led to its detection. Faraday and other chemists of high standing were called in, and the investigation, which was made at the Athenæum Club and elsewhere, proved that the damage was caused by sulphur acids, although the gas was perfectly free from sulphuretted hydrogen, and by no tests applied to the gas itself could the presence of sulphur be detected. Dr. Letheby, then at the outset of his career, thereupon devised an apparatus know as the 'Letheby sulphur test," in which the gas was burnt in small quantity for twenty-four hours, and the products of combustion were analyzed, whereupon the presence of sulphur in some form or other was made manifest. By the Act of 1860, a heavy penalty was imposed for this impurity if it exceeded twenty grains per hundred feet of gas. The Gas Companies, however, were wholly unable to comply with this maximum; the sulphur constantly exceeded twenty grains; but as no one could tell how this sulphur could be extracted, no penalties were ever inflicted. In the proceedings before the parliamentary committees of 1866-67-68, this question was investigated afresh, and as admittedly there was no process known by which this impurity could be extracted or controlled, Parliament handed over the difficulty to be dealt with by the gas referees. But the more the case was investigated, the more serious did the difficulty appear; and when at length in 1870 the large Beckton works of the Chartered Company were opened-pure, without cost, and in any quantity that works constructed with all the best appliances then known-the gas there made was actually much fouler with sulphur than that manufactured at any of the other gas-works in London. Moreover, the Beckton gas being mixed with that supplied from the other stations of the Company, the whole gas in the City became fouler than before. Accordingly the complaints of the municipal bodies became more frequent and more urgent than ever. At length, in 1872, this problem, which had baffled the chemists and gas-engineers for fully twenty years, was solved by one of the gas referees. Since 1848 it had been known, from the laboratory experiments of Berzelius, that sulphide of potassium combined with bisulphide of carbon in laboratory experiments, when these two substances, each pure, were brought together in a close vessel; and in 1865, on the suggestion of Mr. Ellisen of Paris and of Mr. Hawksley in this country, several attempts had been made to employ alkaline sulphides for the extraction of the residual sulphur in coal-gas; but all these attempts failed, so that, as Dr. Odling might be desired, simply by regulating the action of the foul gas itself. Moreover, in consequence of the complete extraction of the carbonic acid by this process, the illuminating power of the gas was increased about ten per cent. above what had been previously obtained from any given quantity and quality of coal. The patent for this invention, being opposed by the Chartered Company, led to prolonged litigation. After a hearing, which lasted for no less than seventeen days, the Court of Chancery decided in favor of the patentee on every point, both of fact and of law; but ultimately the House of Lords decided against the validity of the patent, on the ground that, as the inventor was a gas referee at the date of the filing of the patent, and as admittedly he had communicated one part of it to his two colleagues, such communication must be held to have been a publication, or dedication to the public, of that portion of the patent, and that as one part of the patent was thus invalid, the whole of it became invalid. The invention has served its purpose as regards the public and the Lon The Companies maintain the prescribed degree of illuminating power in a most satisfactory manner. It is a case of exceedingly rare occurrence that the gas is ever found to be below sixteen candle-power as tested at the official stations and with the standard burner. As regards purity, however, the transgressions have been very numerous, and for some years after the Act of 1868 these transgressions were frequent even in the case of impurities-such as ammoniawhich can be easily and profitably extracted. Recently, in one or two instances, the municipal authorities have put the penalty clauses for impurity in operation; and this was a very proper step, inasmuch as there is now no difficulty in supplying gas of the required purity, and transgressions will cease when the Companies know that the penalties will be exacted if the gas be foul, not from unavoidable accident, but from a want of due care and diligence. The old difficulty about the sulphur (other than sulphuretted hydrogen) is now so thoroughly overcome, and the maximum fixed for it can be so easily observed, that in some of the London gas-works it has been the practice to purify only a portion of the gas-in one work only two-thirds, and in another only one-half, from this noxious substance; this purified portion of the gas being so thoroughly cleansed from sulphur, that, when the two portions are mixed, the gas is still sufficiently pure to comply with the maximum fixed by the gas referees-thereby showing that the maximum might be fixed at a lower point than it is. don Gas Companies, by all of whom it has | jection to the present situation of the testbeen adopted; so much so, that since 1872 ing-stations, viz., at a thousand yards from the complaints of the municipal authorities the gas-works, and undoubtedly it would be as to the foulness of the gas with sulphur more satisfactory to the public if those stahave wholly ceased, and the Companies tions were always situated within the dishave been able to entirely avoid any in- trict supplied. fringement of the sulphur-maximum, and the heavy penalties attached thereto, while making a large gain from the superior illuminating power of gas when thus purified. As regards the arrangements for testing the gas, so as to ensure the fixed degree of purity and illuminating power, the public of the metropolis may be well content. The testing-stations are fitted up with the best apparatus and appliances, and there is one station for each of the gas-works. Gas examiners are appointed for these testingstations by the municipal bodies, and these officers are under the supervision of two able and experienced gas-chemists, namely, Mr. Keates for the Metropolitan Board of Works, and Mr. Heisch for the Corporation. A considerable improvement was made by Parliament in 1875 relative to these gastestings. By the Act of 1868, the time during which the official testings for illuminating power could be made was restricted to only a portion of the twenty-four hours-namely, in winter, between four and eleven o'clock p.m., and in summer, between eight and eleven p.m. In consequence, the Companies did not always supply gas of the fixed illuminating power (viz., sixteen candles) during the rest of the day, but raised it to the proper quality during the hours of testing. The position of the testing-stations enables such a change to be made within a few minutes' time. These stations, in accordance with the Gas Acts, are situated, as near as may be, at a thousand yards from each gas-work-an arrangement which is certainly unsatisfactory, inasmuch as in not a few cases the testing-station is entirely outside the district to which the gas is supplied. For example, in the case of the largest metropolitan gas-works, the testing-station is placed on a main from which no gas is drawn for the supply of a single house between the works and the testing-station, nor indeed for several miles thereafter. It is therefore quite an easy operation for the manager to change the quality of the gas as it passes from the works to the testing-place in a few minutes' time. These facts having been brought under the notice of the Committee of 1875, the official testings for illuminating power were allowed to be made at any hour of the day, so as to ensure that gas of the proper illuminating quality should be supplied at all times. But there still remains an ob The lime employed in gas-works has been a fruitful source of complaint on the part of the inhabitants in the neighbourhood, owing to the nuisance which it used to occasion. By the processes now employed it has been proved that this nuisance can be greatly abated. Nevertheless, lime is objectionable in the gas-works themselves, not only owing to its being a dirty and disagreeable material to work with, but also on the ground of expense; and on both of these grounds, especially the latter, the Gas Companies are turning their attention to the liquid processes of purification which formed part of Mr. Patterson's now lapsed patent. By these processes, which were specially devised for use in urban gas-works, the entire work of purification is conducted in permanently closed vessels (called washers and scrubbers), from which no effluvia es- | barrier against any such transfer of their cape, and which can be employed without business. The Board of Trade think and nuisance even in the heart of a city. The say that, when all the Gas Companies have Journal of Gaslighting,' referring to these been amalgamated into one, it will be a simprocesses, said (April 8th, 1873): We pler and easier matter for the municipality should rejoice to see the use of lime super- to take the management into its own hands. seded, on account of its expense, as well as The Companies entertain the very opposite the possibility of a nuisance. The success opinion; and, as it seems to us, the Comof Mr. Patterson's process of scrubbing panies take the more correct view of the case. with solutions of alkaline sulphides would The taking over of so vast a business at one solve the difficulty at once; and compara- stroke would prove a most formidable untively unimportant additions to, or altera- dertaking for our municipal representatives. tions of, the present plant would secure Gas-making, it is true, is by far the simplest complete purification, without offence in of all the large manufactures, and is highly any locality. As regards one of these pro- suitable for being conducted by municipal cesses, the Lancet' says: Mr. Patterson's bodies; yet it requires at least tenfold more process of purifying gas entirely by means care and knowledge than the water-supply, of the ammonia contained in it is at once which is the other kind of business which ingenious, effective, and economical.' In may be advantageously entrusted to municifact, by this process, one gas-impurity (am- pal management. Moreover, any undertakmonia) is made to extract all the others-ing, however simple in itself, becomes arduviz., carbonic acid, sulphuretted hydrogen, and bisulphide of carbon-while being itself extracted. No process can possibly compete with this one in cheapness, while it possesses all the advantages of the best of the others. It has been in operation in greater part since 1874 in the works of the South Metropolitan Company, and is manifestly destined to be the process of gas-purification for the future. Such is a narrative and description of the Gas-supply of London. As already stated, three gas-works on the south side of the Thames (belonging to the Phoenix, the London, and the Surrey Consumers' Companies) have not yet been brought under the above-mentioned system of parliamentary regulations; but this will be effected in the course of a year or two, when these Companies have to come to Parliament for leave to raise fresh capital. The conflict between the municipal bodies and the Gas Companies is well nigh at an end. As regards the future, the two matters of interest are the process of amalgamation still going on among the Gas Companies, and the question as to the ultimate purchase of these undertakings by the municipality. These two matters have an important connection with one another, but this connection is viewed in an entirely different light by the Companies and the Board of Trade. The Board of Trade have favoured and freely given facilities for this work of amalgamation, which facilities have been readily accepted by the Companies. But while the avowed object of the Board of Trade in so doing is to facilitate the ultimate transfer of the gas-supply to the municipality, the Companies regard each successive act of amalgamation as raising a fresh ous when existing on so vast a scale of mag- And The advantages which amalgamation would confer upon the Companies in case of attacks from other quarters remain indisputable. It may be taken as certain that London will not much longer exist without some complete form of municipal government, and then will be the time of trial for the Gas Companies. The day may be a little distant, but it would be well for the Companies to prepare for it. They can only effectually meet a complete municipality by a complete amalgamation. Parliament, we believe, in view of the enormous amount of labour which would devolve on untried hands if the undertaking were transferred, would decide to leave them to the care of those who brought them to so much success. In time of peace prepare for war, is a maxim which may be justly urged upon the Gas Companies. The day of trial, as we say, may be distant, but it will cer tainly come; and we can only, once again, urge upon the Companies the advantages they must derive in a struggle by a consolidation of their interests. It will be observed that the London Gas |