work done by the fan would not be represented. So far as his experience went the water-gauge was generally fixed in the fan drift, and not in the pit. If he had made his experiments with the water-gauge at the separation doors, the comparison would have been of little use. Replying to Mr. Stokes's remark as to a ton of coal not being of much value, colliery proprietors had their own opinion, and if one ton of coal was not of much value, many tons were of much value. Mr. Stokes had pointed to the results of some of these experiments, and he was obliged for it, because he had omitted to state in the table that in experiment 5, where the watergauge was 3.00 inches for 120,600 cubic feet of air, the separation doors were slightly opened, so as to produce exactly a 3-inch water-gauge, the object being to test the guarantee of the makers that the fan should give a certain quantity of air with a 3-inch water-gauge. The other experiments, he thought, would be found to agree theoretically as nearly as possible with the practical results. As to the position of the water-gauge, it would be seen he had made a number of experiments with the object of trying to get at the true place in which to fix the gauge. He then took the mean of these results and therefrom determined the fair position for the gauge; it was very important to ascertain the true position for the water-gauge, as a large apparent difference of useful effect could be arrived at by varying its position. Its proper place to give correct results must be ascertained before detailed observations could be relied on. That he had endeavoured to do by making these trials with the water-gauge before fixing on any position.

The CHAIRMAN-Gentlemen, is it your pleasure that the discussion shall be adjourned or closed?

Mr. LUPTON-I move that it be adjourned.

The proposal was seconded and carried.

DISCUSSION UPON MR. G. BLAKE WALKER'S PAPER “ON COALGETTING BY MACHINERY."

Professor LUPTON said this was an interesting and instructive paper. He should, however, venture to criticize it in one or two points, but would do so with the utmost respect to the author, and not with the least intention of detracting from the value of the paper. In the first place, the suggestion that colliers do not now put forward the same amount of physical exertion that they used to do in days gone by, he thought, was not entirely accurate. Also, the author's opinion, that in the future the most successful coal-cutting machines would be actuated by electricity, was not conclusive; and his remarks as to the great amount of loss of power in the use of compressed air for coal-cutting were capable of explanation, and certainly required confirmation. Without in the least degree desiring to limit electricians in anything they might do in the future, he did ask for a little evidence of the superiority of electricity over compressed air. As soon as that evidence was brought forward he should be ready to welcome it and make use of it. Mr. Walker

had limited the useful effect of compresed air to 20 per cent., but with reasonable care he (Professor Lupton) had no doubt two or three times that amount, from 40 to 60 per cent. of useful effect, might be got. Because, at those collieries where they produce material which will burn, but which, as had just been stated, could not be sold at any price, there had not as yet been put down the most efficient air-compressors, and consequently the results in these cases did not show a high theoretical efficiency, it did not follow that a high efficiency was unattainable. Compressed air was so suitable to be taken into the innermost recesses of a mine that he did think it a mistake to advocate with confidence the use of electrical machines as superior in efficiency without some proof of the proposition. He had had some little experience of coal-cutting machines, and had carefully studied them for the last twenty-five years. It was twenty-five or twenty-six years since he went down the pit, which was now under Mr. Walker's charge, to start the first of the coal-cutting machines in that pit. He had watched them with great interest since, and it seemed to him that the difficulty in getting coal-cutting machines more generally used was not because colliers would not put forth great physical force, but because they actually did put forth so much force that it was difficult for steam power to compete with them in seams of the kind chiefly wrought. These were the actual facts as against the theories of people who spoke a priori. The fact was, in ordinary seams coal-cutting machines had not hitherto been able to maintain themselves against hand labour as a general rule; but where the seam was thin, or the holing hard, or the management more than usually determined, they were more successful.

Mr. LONGDEN said, in his opinion, compressed air as a motive power was extremely wasteful, and electricity was by comparison distinctly economical. Mr. Blake Walker's paper was one of extreme value, and he should be sorry indeed if the discussion were to be closed without allowing full time for discussion. The question of electrical coal-getters had been taken up very thoroughly by the Institution of Civil Engineers, and Mr. Arnold Lupton had replied, upholding compressed air, and had been replied to at great length by electrical engineers. Without disparaging mining institutes, he thought the electrical part of the problem had been maintained by the civil engineers in a more thorough manner than mining engineers could do. He was now speaking as a mining engineer, and with the knowledge that electrical engineers were in the room. In a short time he purposed asking the members of the Institute to see air-compressors and dynamos in use at collieries with which he was connected.

Mr. C. E. RHODES said this question of coal-cutting machinery was a most

important one, especially for those working thin seams where the waste due to cutting by hand labour was an important element, and as he had had many opportunities of seeing Mr. Walker's coal-cutting machinery at work at the Lidgett Colliery, he could speak with some amount of confidence upon the subject. Anybody who, like himself, had had an opportunity of seeing the system in operation there, would come to the conclusion that the commercial prosperity of that colliery

was due to the admirable manner in which this system of coal-getting by machinery had been applied. There was no doubt that the seam, if it had to have been holed by hand, with the strong floor that exists there, would have been simply chopped to pieces in the process of holing, and the saving in small, due to cutting by the machine, with such a valuable coal as the one in question, had made all the difference between a commercial success on the one hand, and a heavy loss on the other. In addition to the advantage just indicated there was another, and that was that the coal, when it was once holed, could be got down and practically filled into corves in a great measure by unskilled labour; that was to say, the skilled labour could be confined to men following the machine and timbering the places and making them safe after it. There was no doubt in his mind that in the future the introduction of coal-cutting machinery would form an important point in connexion with mining. He lately introduced a heading machine which he had previously seen in operation at the collieries of the Staveley Coal and Iron Co., and the result was that they were enabled to head a number of yards in a day which previously would have taken a week by manual labour. He did not think so much was saved in the cost per yard, but there was an enormous advantage in being able to open out a colliery at the rate of 60 yards per week, and thus develop and prove a coal-field with a rapidity it would be impossible to achieve by any system of hand labour. With regard to the power for driving this machinery, there could be no two opinions as to the economy of electricity over compressed air, not only in respect of the useful effect obtained from the initial power, but also the comparative economy in conveying it. No one could get with compressed air more than from 30 to the very outside 40 per cent. of useful effect, at least he himself had never been able to do it, but with electric machinery there was no doubt a very much higher useful effect could be obtained. The difficulty, he said, with regard to the application of electricity, especially in fiery mines, was the danger of sparking, and it seemed to him an absurdity for coal owners who had gone to the expense of introducing safety. lamps, abolishing gunpowder and all explosives of a nature calculated under any circumstances to ignite gas, which there was no doubt had involved an increased cost of production of from 3d. to 6d. per ton, then to introduce a power, simply on the ground of its economy, which threw off sparks, and which in itself therefore was as bad as a naked light. This was the only, but grave, objection he saw to the introduction of electricity for mining operations. It was a difficulty possibly which in the immediate future electricians would be enabled to overcome. Such enormous strides had been made in the last few years by the ingenuity of those gentlemen to whom all owed so much that he thought they would be able to achieve what was essential to the safety of those employed in mines, if electricity was to be largely used, and that was to overcome the danger due to this sparking. It was a point, he thought, that all would agree to commend to their special efforts, and he had no doubt that during the next few years some means would be discovered to obviate this grave danger.

Mr. DEACON said, with reference to the last remark, there was an electrical machine or appliance somewhat of the type suggested now at work. It was called the Davis and Stokes safety commutator, in which the brushes being placed inside the commutator, instead of outside, and the whole cased in, all the sparking took place inside the commutator chamber, and could not communicate with the air of the mine. It had been run for a week perfectly satisfactorily, and he (Mr. Deacon) believed he was to have the honour of fixing the first in a pit of the Blackwell Company. In reply to Prof. Lupton, he added that it would be employed for pumping in a colliery which was worked with safety-lamps.

Mr. G. J. BINNS did not think there was much reference in Mr. Walker's paper to the Harrison coal-getter, and as he had failed in obtaining information as to where that machine could be obtained in England, he should be glad if Mr. Walker or any other gentleman could tell him. It was one which was largely used in America, and its use obviated many of the objections which might be raised to the ordinary type of rotary coal-cutting machine. It was a percussive coal-cutter; in fact, a rock-drill on wheels, which could be moved anywhere in a moment. One man could work it, holding the handles, while another shovelled away the débris, It was a very small machine, and very inexpensive. There was another machine of the same kind, made by the Ingersoll Rock-Drill Company, which appeared to be as good as the Harrison. The object with the rotary coal-cutter was to make the whole machine fast to the rails; whereas the object of the other was to have it as free on the road as a perambulator in the street.

Mr. J. R. GILCHRIST apologized for the absence of Mr. Walker, who had fully intended being present at this discussion, but was called away at the last moment. In his absence, he (Mr. Gilchrist) should have been glad to answer any questions that might have been put. But only one remark appeared to call for any comment on his part, and that was made by Professor Lupton, who appeared to be somewhat in error as to what Mr. Walker mentioned as the percentage of useful effect that could be got out of compressed air. He understood Professor Lupton to remark that Mr. Walker maintained that only 20 per cent. of useful effect could be obtained, whereas referring to Mr. Walker's paper, he said, "If 40 per cent. of the power put into the steam cylinder issues from the air cylinder into the mains, it must be considered an exceedingly good result," and in referring to the 20 per cent., Mr. Walker was applying this as the probable useful effect at the face of the workings, after allowing for loss of leakage, etc., at the numerous joints of pipes. As regarded coal-cutting machines, he believed they would be more largely used in the thin seams than the thicker ones, and could corroborate the remarks made by Mr. Rhodes as to their working in a thin seam at Lidgett Colliery. There, the underholing was very strong, and it was a case where he did not think they could get manual labour to do it. Coal-cutting machines enabled this colliery to work to advantage; whereas without machines it could not be successfully worked, at any rate, commercially.

Professor LUPTON moved, Mr. JACKSON seconded, and it was agreed nem. con. that the discussion be adjourned.

The CHAIRMAN said they were not in a position to discuss Mr. Russell's paper, and therefore the proceedings were now at an end. He must congratulate the Institutes on their first joint meeting, and hoped that it was only the first of many meetings that might be held jointly to the benefit of each institute.

Mr. LONGDEN moved, and Professor LUPTON, seconded a vote of thanks to the Chairman, which was carried and duly acknowledged.

DINNER AT THE ROYAL VICTORIA HOTEL.

MR. JOSEPH MITCHELL, PRESIDING.

After the usual loyal toasts,

Mr. THOMAS CARRINGTON (Past-President of the Midland Institute and VicePresident of the Federated Institution of Mining Engineers) said that he only supposed he had been asked to propose the toast which had been placed in his hands in consequence of the absence of Mr. Parker Rhodes (whose seat he occupied) and Mr. Emerson Bainbridge. As that was so, and as he had been called upon at a moment's notice, he trusted they would extend to him a good deal of indulgence and forbearance, particularly as he had, as it were, to propose two toasts in one. They were, "Success to the Chesterfield and Midland Counties Institution of Engineers and the Midland Institute of Engineers," and the "Learned and Scientific Societies." In proposing a toast which involved the healths of the "Mining, Civil, and Mechanical Engineers," and "Learned and Scientific Societies," he was really proposing the healths of their "noble selves," and doing it twice over, too. No institution of civil, mechanical, or mining engineers could be carried on successfully without due attention to the laws of nature; in fact, the application of physical forces of various kinds, and their conversion, adoption, and application to the uses of man was their daily occupation; therefore they as engineers must be ever closely identified with the learned and scientific societies, the latter being as it were the pioneers in discovering physical laws which it was the duty and province of engineers to apply for the purpose of obtaining practical results. During the last few years it had become more necessary than ever that they should keep pace with the times; for instance, they had seen already what an investigation of the laws of the forces of nature with regard to electricity had resulted in, and what marvellous developments had followed and will still follow. And when they remembered that in America there were kindred Institutions, who were as much alive as they were to the benefits of careful observations and verifications of facts in regard to physical science and the conclusions to be drawn therefrom, it was more incumbent on them than ever to carefully investigate these same laws and to interrogate physical phenomena to the fullest extent. With regard