great public service, in supplying a purer gas for combustion in rooms. II. That the rotary arrangement suggested by Mr Reid, and practically carried out by him at the gas-works in Leith, is a great improvement upon the apparatus hitherto employed for that purpose. III. That whilst the purification of air is best carried out by removing the source of the contamination, yet, where such is impracticable, the washing of the air will be beneficial, and Mr Reid's apparatus is the best arrangement which has as yet been suggested for accomplishing that end. IV. That Mr Reid's paper deserves the special attention of the Prize Committee, for the material improvement it effects in the means for the purification of coal gas and ordinary air. STEVENSON MACADAM, Ph.D., Convener. ROBERT AYTOUN. EDINBURGH, 15th March 1867. Observations on the Construction of the Track of Railways. By W. J. COCKBURN MUIR, C.E., F.R.S.S.A.* Mr PRESIDENT AND GENTLEMEN,-The permanent way, as the track is termed in this country, forms so serious an item, both in the first cost and the maintenance of railways, that in pointing out a method by which, in both directions, I believe a large saving may be effected, and at the same time increased efficiency secured, I hope to enlist your attention either as being technically concerned, or as shareholders having an eye to dividends. In this country passenger-rates are generally much higher than on the Continent. The average rates in Great * Read before the Society, and models and drawings exhibited, 25th March 1867. Awarded the special thanks of the Society. VOL. VII. 2 N Britain are one penny, three halfpence, and twopence per mile, for the third, second, and first class respectively. In some cases, as for example where there are competing lines, the through fares are reduced a fraction below the average. But frequently the second class fare is a penny-threefarthings, and even twopence per mile, and the first class twopence halfpenny, or more. On the other hand, in France the average is a fraction under a penny (Fr. 0·095) for the third, a penny-farthing (Fr. 0-13) for the second, and a fraction under a pennythree-farthings (Fr. 0.17) per English mile for the first class; being the same as for the second on many of our lines. In Prussia the average is still lower, being four-fifths of a penny (pfen. 8) for the third, one penny and a tenth (pfen. 11) for the second, and only a penny and three-fifths (pfen. 16) per English mile for the first, or about the same as our second class. In some parts of Westphalia and East Prussia, there is a fourth class for the poor peasantry at less than a halfpenny (pfen. 4). Although exceptional, this is a fact worth noting. The minimum is reached in Belgium and some of the Rhenish lines. The third class is a little more than a halfpenny (Fr. 0.06); the second, a little under a penny (Fr. 0·10); and the first, a penny farthing (Fr. 0·13)—just the rate of the French second, and less than our second by a farthing a mile. Then we must remember how superior are the fittings and appointments of the second class carriages in these countries. In merchandise freights also the proportions are about the same as those quoted for passengers. The causes which render low rates possible and profitable there are various. The preliminary expenses are enormously less than ours. The cost of obtaining legal sanction is merely nominal. Parliamentary contests are absolutely unknown. Cost of surveys is less. Value of land is very much less. Labour is cheaper, and although, as is well known to engineers who have been engaged abroad, the quantity of work done per man per day is less than at home, there is a balance in the long run in favour of the foreign labour. In working expenses there is some advantage against us, owing to the smaller salaries which content the officials. Something is also due to governmental assistance by guarantees, though not to the extent laid down by a writer in the last "Edinburgh Review." He assumes that the Continental public "pay in taxation for the saving to travellers and the gain to shareholders." That is a startling announcement for those who are familiar with the working of railways in Western Europe; because we know that, as a rule, on the main routes the returns are fairly remunerative of the capital outlay, apart from any complication of the question by government guarantee. As regards the subsidiary lines, it is very uncertain whether they will ever become the burden on the State, assumed by the reviewer as probable, for instance, in France. But admitting the probability, it is a question of the future, and does not affect the results of the past. The causes on which low rates of usance depend on the Continent are, however, so special in character, that they can never become operative in this country. We may reduce parliamentary expenses, but we cannot make land cheaper, nor labour, nor reduce the cost of staff service. Therefore, in indicating the contrast between foreign and home rates, it is not intended to assume that we can ever travel so cheaply here as, for example, in Belgium,—such a hope would be quite delusive,-but, by pointing out how high we stand in our scale of charges, whilst our dividends are notoriously meagre, to lead us to consider the importance of economising our operations in every direction which, on examination, may appear possible. If we may not hope to accomplish any sweeping and ambitious economy, we may at least attain appreciable results in considerable items. It is with the belief that in one of these items, the permanent way, a considerable reduction in the present outlay is to be had, that I ask you to consider with me the bearings of the question as deduced in the progress of trackconstruction. In what I have the honour to lay before you, I shall endeavour to avoid mere theoretical probabilities, and confine myself to the results of trial and experience. Within the limits of an occasional paper it would be impossible, and if possible, excessively wearisome, to give an exhaustive view of the whole subject. For the sake of your patience I will condense as much as possible the many considerations involved. First, to explain why I prefer to use the Americanism "Track," rather than the usual phrase "Permanent Way." The latter was originally used as distinctive from the "temporary roads" laid by the contractors in building the line, and not as expressive of a positive quality of permanence in the road. Because under any circumstances this requires to be renewed at intervals, and cannot, therefore, be said to be "permanent" in the same sense as a bridge or culvert. So that "track" better expresses the nature of the thing, and it is shorter. Before we can form an opinion on the relative merits of different systems, we must have clearly before us the essential conditions to be fulfilled by any track. The simple statement of the work to be done is, that trains are to be carried. But there are very important variations in the degree of that work. According to the nature of the traffic, the trains may be light or heavy; may have to run at a low or at a high speed. For light trains at a low speed it matters little, so far as safety merely is concerned, what kind of track be used. For heavy trains at a low speed, we have only to see that we have sufficient bearing-surface and sufficient strength of rail and fastenings. The true final test, then, of a good system of track is, that it will carry heavy trains at high speed with assured safety. It is obvious that a system which will bear this test may be adapted for all gradations of traffic, down to a minimum, by merely reducing the dimensions, or sections, or strengths, which are different expressions for the same. thing, of the various members. What, then, are the conditions a track must fulfil in order to do this work? Assuming that we have a stable and even surface, or "formation," on which to lay the track, we find the first essential to be-that the actual bearing surface be kept constantly dry. If the wet accumulate, in however small quantities, under |