across the whole breadth of the generator, and pierced with very small holes on the outer side. These are to supply the steam necessary to wash up in the fuel, towards the end of the run, the gases from the heavier hydrocarbons, which sink in the fuel instead of rising. The air-blast K enters below the bars from one side. A Roots blower is better than a fan, as it gives an absolute pressure. It should be large as compared with the work it has to do, as a good deal of economy is derived from a very rapid, and what a few years ago would have been considered an excessive, "blow," as the more complete the combustion-i.e., the less carbon monoxide-the less fuel is used to gain a given temperature.

The form of the generator, although awkward, is of importance, as when using a tar or heavy oil, there is a lot of carbon liberated from it; and I find that if the gases have to pass through the top layer of but little heated coke, it acts as a filter, and does away with a good deal of the risk of choking in the superheater. The deposited carbon also is brought down by the coke to the zone of combustion, and is utilized; while the coke itself is dried and heated before being burnt. The superheater has the top part built in with a chequer work of fire-brick, which can rest on a grating at L; while the lower part is built up of pig iron or old furnace bars, which during the run decompose any surplus steam to hydrogen, and are again reduced to iron in the next blow. The floor of the superheater must slope down to the exit M; so that if, as the result of improper temperatures, any tar condenses, it will run down to the hydraulic seal.

In working the generator, the fuel is put in until full up to the top of the charging-shoot, all openings are closed gas-tight, and the "snift-valve" N is opened. This valve consists of a heavy iron cap working on the faced top of the blow-off pipe, to which it is hinged, as shown. It works very well in practice; and the importance of doing away with valves for the hot gases cannot be overrated. The fuel being lighted, the blast is turned on, and is kept blowing until the fuel shows red through the sight-hole O, consisting of an iron pipe with easily removable cap glazed with mica, which has to be taken off and cleaned from time to time, as a little tar vapour condenses on it. When the fuel shows red at the sight-hole, the air-blast must be cut off (there must be a valve between the blower and the generator, as close to the generator as possible), the snift-valve closed, and the oil and high-pressure steam turned on to the three injectors; the exhauster being started to give a level gauge at the gene

rator. The minimum quantity of steam must be used; and after the injectors have been going a minute, the steam is turned on below, and the run continued until the temperature seen at the sight-hole is reduced from a bright to a dull red. The oil and steam to the injectors are then stopped; but the steam at the bottom is continued for a minute, to wash all hydrocarbon vapours out of the fuel and superheater. When the steam is cut off, the snift-valve is opened, and the blast turned on full until the temperature again shows bright red.

Pipes must lead from the generator and other parts of the apparatus to a series of gauge glasses fixed on the same board, so that the man in charge can regulate the speed of the exhauster. There should be a manhole into the superheater at the side P; and in making the generator, it should be so constructed that every part is easily accessible. In case of a failure in the carbide supply, this generator works equally well with "solar distillate" or other gas-making oil.

Discussion.

Mr. T. G. MARSH (Manchester) said he had not had an opportunity of examining this water-gas plant; but he had, on several occasions, seen a description of it, before it came into use. Water-gas plants that were in use now took up considerably more space than the generator in this plant would appear to do. The plants which he had seen on the other side of the Channel were so large that there would be considerable difficulty in putting them into many of the Irish gas-works, in con. sequence of the price of the generators. The generator in this plant appeared to him to lend itself more particularly to mediumsized works. With the generators he saw on the other side of the Channel, a very great amount of care had to be exercised, because, if the operator in charge of the machine was at all careless in the time of his passage of air and his passage of steam, the result would be that a very serious defect would be encountered. For instance, if he continued to run steam too long through the generator, the coke became sodden; and they would find, in addition to getting the carbonic oxide sent forward, that they would send forward a large percentage of carbonic acid. They all knew that, if they sent carbonic acid forward, they had to take it out again; and consequently there was considerable expenditure required for purifying material. Further, the extra quantity of carbonic acid sent forward required to be enriched by the oil; and therefore they would have to incur an extra cost for oil as well as for purifying material. The apparatus

before them looked to him to be much simpler. It was very compact. It had the generator and the superheater all in one. As to how the carburettor acted in the same generator, he was not in a position to say. This was a matter which could only be found out by a series of tests, which, he felt confident, no one was more competent to make than their President, Mr. Tully, who he knew had given a considerable amount of time to the chemical aspects of the subject. The advantage of this gas of Professor Lewes's was that there was nothing like the quantity of carbon monoxide that there was in water gas as used generally. As he had said, one of the difficulties with water gas was the quantity of carbonic acid sent forward, through no want of care. Mr. J. W. Helps, of Croydon, applied to him some time ago in regard to this matter, and said he found that though the man attending to his generators had very little work-all he had to do being to look after some valves, and close one for seven, and open the other for three minutes— he had to watch the clock. This seemed to be looked upon as no work at all; but Mr. Helps said that if he had to do it he would think it very hard labour, and that the only possible man they could get to undertake it would be a man without any thought or mind at all—that, in fact, it was a most arduous job. In a few instances, they had an electric bell. Mr. Helps told him if they made a run a minute too long, the carbonic acid increased by 9 or 10 per cent., which was, of course, disastrous. He suggested that some mechanical means might be arranged; and there would be very little difficulty about that. He (Mr. Marsh) was fixing up there now a simple arrange. ment by which they could check the man, and see if he kept the time required-in fact, make his life a little bit more miserable than it was at present. In addition to this, he had made a machine which he had just patented, and which was rather a peculiar one. It was an automatic analyst. It was a machine which would make a diagram, in the same way that a pressure register did, and show the proportion of carbonic acid there was in the gas, as it was made and as it was sent forward; so that the manager could himself see the diagram in the morning, and ascertain the proportion of carbonic acid which had been sent out during the night. This, of course, was a thing which was more applicable to medium and large-sized works than to small With the apparatus in question, they would not have nearly the amount of trouble they had at present. In the matter of the price of coal, he was entirely at one with the President that the ill had its remedy; and though the high price they had

ones.

been charged for coal now might appear to them to be likely to reduce their profits, he was satisfied in his own mind that it was one of the great benefits they had that occasionally their raw material went up in price, for the simple reason that if they got a thing too cheap, they became wasteful of it, and did not seek to save it. In regard to coal as it was used in gas-works now, and as it was employed some twenty years ago, they were selling 10 per cent. more gas per ton than they made then. The result was that, with the high price of coal, those who used it would apply the resources of science, and do everything they possibly could to save the coal. The price would then go down; and, when this happened, they would have much greater profits. He believed an advantage would come to them in this way. The price of coke would be most materially enhanced on account of the high price of the coal with which it competed. But, in addition to this, water gas had been introduced very largely, not so much for the purpose of competing with coal gas (because water gas was not very much cheaper than coal gas when they had to use oil which had also gone up in price), as to enable them to meet sudden contingencies. These water-gas plants would use up a large proportion of coke; and when this occurred, a scarcity of coke would be experienced-not an artificial scarcity, but a real one.

Mr. G. W. NORMAN (Dublin) said he would like to ask the President, for the information of gas managers in smaller towns than his own, about the general cost of the plant. He wished to know whether it would be useful for smaller works, and whether they could go in for it at once.

Mr. S. B. LANGLANDS (Coleraine) asked if Mr. Marsh could tell them whether the apparatus he spoke of for showing the overplus of carbonic acid was a chemical appliance.

Mr. MARSH said he did not know that there was any particular secret about the machine, because it simply carried out mechanically the old process which the ordinary analyst did, and marked it on a diagram. Of course, he had had a great many troubles in connection with it, as they had in most things-the idea, for instance, in connection with automatic meters, which he first brought out. But he thought he had got this thing right, and that in a few months' time they would have illustrations of it pretty generally.

The PRESIDENT said, in reply to a remark by Mr. Marsh, that, of course, it was possible to carburet the gas in the apparatus, by introducing the oil into the superheater at the top; but he did not intend to do so. He meant to carburet the gas as it

left the works for the town, through an independent carburettor. As to carbon monoxide, they would see that Professor Lewes's carburetted water gas contained 15 per cent., as against 33 per cent. in ordinary carburetted water gas; and it came very close to ordinary coal gas-being only 5 per cent. more. It was this fact that induced him to adopt Professor Lewes's process. Mr. Norman asked the cost of the plant. He thought that an ap. paratus such as he had could be fitted up complete, with blower and gas-engine, for from £200 to £250. That was a plant capable of making 50,000 cubic feet of gas per day.

ENRICHMENT OF GAS WITH BENZOL OR OTHER LIGHT HYDROCARBONS.

The PRESIDENT introduced this subject. Referring to the accompanying diagram, he said that some time last winter he looked into the question of the enrichment of gas with benzol, and he set about designing and constructing the apparatus before the members, which had been working since February last. In the period from the 8th of February to the 8th of July, 9,166,000 cubic feet of gas were made, of which 4,583,000 cubic feet, or about 50 per cent., of the whole, was passed through the apparatus in the hours between 30 minutes before sunset and II p.m. The enriching medium he used was crude naphtha —the first runnings—of about 8'928 sp. gr. They had used 106 gallons of naphtha, at iod. per gallon. The total cost of enrichment was £4 7s. 6d., and the cost per 1000 cubic feet worked out at 0'23d. Coke baffling was used in the apparatus. The gas he supplied ordinarily was of about 15-candle power, and this enriched it up to about 18 candles. He found that the gas passed through the town in from five to ten minutes. The naphtha vapours were taken off at the ordinary temperatures, and they had not time to deposit, and did not deposit, in the town mains; neither had they affected the meters. The appliance was exceedingly simple.

[The President had a small glass experimental apparatus on the table, with one light burning unenriched gas, and another enriched gas. The effect of the enrichment was quite apparent.]

In answer to a question, the PRESIDENT said the cost of the apparatus would be, perhaps, from £50 to £70, according to size. He must say that he would be very sorry now to be without it. He had it fitted after the governor.