larger stations, and a probable outlay of ten millions. If the capital account was to be closed, then for three years no dividend would be paid, though such traffic would bring three millions more net revenue, and add sixty millions to the value of the undertaking. Now, considering the class of persons who held that property, such an act as that would be one of confiscation. Then again, there was the question, under what circumstances and conditions could branch lines and extensions be usefully and beneficially undertaken? And again, the connection between the Government and the railways, on which extreme opinions existed. There were those who thought that the Government should take the railways into their own hands, as they had done the telegraphs; while others considered it better that the railways should be independent of the Government. His own feeling was that an intermediate course might be taken with advantage to all parties. The discussion which took place at this Institution on the Atmospheric Railway,' if it did not entirely prevent the waste of capital in the attempt to carry out that system, certainly lessened the expenditure that would otherwise have been incurred; and he believed there never was in the Institution a more useful discussion, or one which had been more practically beneficial. Mr. Mosse's Paper had opened up another point which was introduced by Colonel Morrison, who seemed to be under the impression, that Mauritius being an island rather less than 40 miles in extent, with a rough surface, the money expended on the railways would have been more usefully laid out in perfecting the ordinary roads. Looking at the district passed through, and the sparse populations in immediate contiguity with the railways, he thought it probable that the improvement of the roads of the island might have given greater general accommodation, and have duced a better effect than a railway through one part of the island only. He readily conceived that might be the case; therefore the remarks he had made as to the advantages of railways generally must be taken as being to a great extent governed by the questions of common sense and commercial requirements. pro Mr. HAWKSHAW, Past-President, said the estimate for the North line was £342,530, and that for the Midland line £434,131, making a total of £776,661, and he believed those estimates had not been exceeded, in any appreciable degree, so far as the works were concerned, and that the colonists voluntarily entered upon this expenditure. The ultimate total average cost of £21,876 per mile was due to other causes. There was what was called the Town line, about 1 mile in length, which was projected by the 1 Vide "The Peculiar Features of the Atmospheric Railway System," by G. Berkley. Minutes of Proceedings Inst. C.E., vol. iv., p. 251. colonists themselves, and with which he had nothing to do excepting to direct the works. That line was very costly, but whether profitable or not it was a matter for the colonists themselves. Again, the land, which it might have been supposed in a colony like Mauritius would have been obtained for a small sum, had cost £195,144. The general opinion appeared to be that the price paid for the land was excessive; but it was a matter over which an engineer had no control. Then labour had to be imported to such an extent that a sum of £64,000 was put into the original contract for this contingency. If railways were made where labourers were scarce, it could not be expected that the work could be executed at a small cost. The wages of carpenters ranged from 3s. to 4s. per day; of masons from 3s. 6d. to 4s.; blacksmiths 3s. 6d. to 4s. 6d.; Creole fitters 3s. 6d. to 6s. 6d.; and labourers (exclusive of rations, &c.) 18. 2d. to 1s. 6d. per day; and though these wages might not appear excessive, it must be taken in connection with the quantity of work done per man, which was small. The average amount of earthwork excavated per man per day was about 11 yard, and the average amount of embankment from the loose soil and stone of adjacent fields was about 11 yard per man; so that the labour was in fact costly. With regard to the working expenses of the line per train mile, no doubt they were heavy; but coal cost 45s. per ton, the wages of drivers and of skilled labour were high, and the per-centage of working expenses, as stated in the Paper, had not much bearing on the question, because that depended upon the amount of the traffic. On this line the traffic had hitherto been limited-first, because the line had only recently been opened; secondly, on account of the extraordinary mortality which occurred in the island, and which in Port Louis alone averaged as many as 207 per day-a rate sufficient to have exhausted the whole population of the island in a year or two; and, lastly, the island had been visited by one of the most terrible hurricanes ever experienced, which destroyed the crops, and a large number of buildings. These calamities, occurring almost simultaneously, were certain to diminish the traffic. The weight of the eight-wheeled coupled locomotive engines was 46 tons and not 48 tons. Fig. 1 showed the leading dimensions and form of these engines, and the way in which the weight was distributed, from which it would be seen that the weight upon any pair of wheels was in fact less than was common in this country. He certainly could not explain how it was that an alteration of th of an inch in the lead of the slide-valves should have increased the power of the engines 10 per cent., and he was very doubtful about the fact. In the first place it could not be done unless the power of the engine previously was less than the amount of adhesion, which he doubted. The Author had expressed the opinion, that for a long rise no gradient should be steeper than 1 in 40, and, on the other hand, in the course of the discussion Mr. Longridge had alluded to gradients of 1 in 12. On the subject of gradients, without attempting to enter at present into the large question which Mr. Bidder was desirous should some day be discussed, he would say he should be sorry if any precise rules were laid down either about curves or gradients. Attempts had been made to do so for the last thirty years. He remembered the time when, in the House of Commons, it was urged that trains should not be taken round curves of 40 chains' radius faster than a limited speed per hour: and he also remembered when it was said that locomotives ought not to be employed for gradients steeper than 1 in 50. All these propositions were hourly set at nought: and he trusted no attempt would now be made to lay down such laws. The fact was, all these questions were matters of experience, and it was the duty of the engineer to consider the particular circumstances and physical features of the country where railways had to be constructed, and then to devise that mode of construction which was the cheapest and the best for those circumstances and for that country. It was idle to say, if railways were wanted in a country the surface of which was like a pyramid, that the lines must not pass over its surface, more especially if the population lived there; and if the lines did pass over the surface, then the gradients must conform to the natural configuration of the country. Whatever discussion was entered into, either now or at any future time, he should strongly object to any one laying down rules which would cripple and check the inventive talent which had made railways what they were: what they might be ten or twenty years hence no one could pretend to say. Mr. GREGORY, President, said, in the face of the extreme interest of the subjects which the Paper had opened, he regretted that the discussion upon it must be closed. Under the circumstances he would not attempt to sum up the discussion; and, indeed, much that he might have said had been anticipated by those who had spoken. While interested in the discussion that had taken place on the effect of gradients on the working of railways, that subject had been by no means treated exhaustively; and he was sure all would agree with Mr. Bidder, that there was still a large field of discussion open connected with railway operations, in the Economy and Politics of Railways. It must not, however, be attempted to crowd too much into one Paper. There were some branches of those subjects which could be treated by Mr. Bidder with an ability to which few could hope to attain; and he hoped that gentleman would carry out his own suggestion, by favouring the Institution with a Paper on one or other of those important questions. Meanwhile, there were many members who must have valuable experience as to the effect of gradients upon the working of railways. He was lately looking through the Minutes of Proceedings of the Institution, and he found the information on that subject, though very useful, scattered through a large number of Papers. He thought if some member would take up the special subject of the effect of gradients on the working of railways, giving the results of experiments and facts within his own knowledge, certain rules might perhaps be established which would serve as a guide in deciding upon the gradients which, under different circumstances, would be most economical, where nature and circumstances gave an engineer a choice; but, as was justly said by Mr. Hawkshaw, very often it was necessary to take such gradients as Nature would allow, and with respect to which no choice was left. February 9, 1869. CHARLES HUTTON GREGORY, President, in the Chair. THE discussion upon the Paper, No. 1,202, "The Mauritius Railways-Midland Line," by Mr. Mosse, occupied the whole of the evening, to the exclusion of any other subject. February 16, 1869. CHARLES HUTTON GREGORY, President, No. 1,214.-" On the Lagoons and Marshes of certain parts of the THERE are many important departments of Engineering in which considerations of Physical Geography and Geology enter largely and directly, and cannot safely be neglected. In subjects of this kind the observations of those who are not by profession Civil Engineers, but whose pursuits are in some measure analogous, have been too often and too directly appreciated by the Members of this Institution to admit of any doubt as to the reception of a Memoir treating on one of the most interesting among them. No apology need therefore be offered, for submitting the result of inquiries and observations made within the last three years, on the northern shores of the Mediterranean and the eastern coast of Corsica, with a view to determine the history of the lagoons, salt marshes, and swamps, that are there frequently accompanied by the worst forms of malaria, and of which there are so many examples. The Author is the more induced to direct attention to this subject, as he believes it to be certain, that a careful study of the mode in which the lagoons have been formed will in some cases suggest a simple method of sanitary improvement, and in others may point out in what way the marshy lands, now useless and poisonous, may be converted into cultivated fields, yielding luxuriant and profitable crops. He will endeavour to show that certain principles, based on the physical geography of these coasts, and dependent on their local geology, explain all the peculiarities of each separate case, and that a knowledge of these principles is indispensable for the effectual and economical removal of the evil, either by drainage, or by retaining the waters near a fixed level and uniformly salt. In justification for venturing to offer an opinion and advice, in a matter which may seem almost too exclusively engineering for a geologist to treat upon, it may be stated that the Author has from time to time had occasion to visit and examine professionally a number of instances of malarious coast connected with lagoons; that he is familiar, not only with those of the Mediterranean and of the Black Sea, but with others in the West Indies and in North America, and that he is acquainted |