"I have shown two ways by which a saving may be effected; the first by simply closing the throttle valve, and reducing the necessary number of fires; the other by working expansively. The evident advantage possessed by the latter mode points out that the former ought only to be resorted to by steamers which are not fitted with the expansive gear. "I will now call your attention to the manner in which steamers have heretofore, with rare exceptions, been handled at sea; and which I declare to be in direct violation of the dictates of common sense. I question not my assertions on this head will also be denied ; but by the blessing of Providence, unless they falsify their own logs, I will make good my charge; let them so stultify themselves, if they please; I heed not, but shall take particular care that such conduct be brought under the consideration of the Ephori, to be dealt with according to its merits. "Were I to write with more warmth, I could show sufficient reason; for as yet, any attempt on my part to elicit information has been met both with ridicule and contempt; so painfully have I felt this in some instances, that I have refrained from visiting the engine rooms, and asking any questions, though urged by the strong necessity of obtaining certain information, ere I expressed a decided opinion; and was therefore driven to the only alternative of wading through entire works, when one single reply to a question would have solved all doubt. These charges I do not prefer against the junior classes alone, for some palliation might be found for their folly, but when men high in rank in the service hope to deter me by such speeches as this, what can I think? 'I assure you, you are quite mistaken: it is impossible to reduce the consumption of fuel, and by that means add to the general efficiency of steamers; for my attention, with all the advantages of situation,-of command, has been directed to it for years without effect. With what show then of reason can your expectations be founded?' Such arguments, being addressed to one endowed with a naturally indomitable temper, served only to stimulate, but could not deter. "The case to which I allude is where full power is kept up, steaming against a head sea; when it is evident, from the number of revolutions, that half the steam must be running to waste. This is a contest between folly and nature, therefore not difficult to divine which must be the victor. All seem to consider it essential to keep full power on to make any head way; but the pressure is a constant quantity, and if the piston does not descend the steam must escape somewhere; at times, however, it will act to the injury of the engine; for, should the wheels momentarily be freed by the vessel's sending, they will revolve with a speed even above the number that imparts the maximum velocity, and when they are again immersed receive a check that reduces their revolu tions to less than one-half.* The watchful seaman whose sagacious eye, 'On sure experience may with truth rely; 'Who from the reigning cause foretells th' effect, This barbarous practice ever will reject.' "I wish to record the following opinion, but shall not support it by argument, as my judgment has been formed on a careful consideration of a number of secondary causes which, taken separately, would fail to convince: The greatest exertion of power does not at all times impart the greatest velocity; decrease your power, and you will, against a head sea increase the velocity! "As I have taken some liberties with the works of Doctor Lardner and Captain Otway, I think it but right to acknowledge, that to those gentlemen, in conjunction with Hugo Reid, I am indebted for such information as was essentially necessary to enable me to carry out the above reasoning." The Oregon is the name given to a steam-boat recently launched at New York, which is 10 feet longer than the Great Britain. She is about to be placed on the New York and Providence station. Locomotive Manufactory at St. Petersburgh.-There exists in the capital of Russia an immense establishment of the above description, belonging to Messrs. Eastwick and Harrison, of Philadelphia, who have entered into a contract with the Russian Government to furnish all the machinery necessary for the construction and working of the vast lines projected in the whole empire. They employ at St. Petersburg not fewer than 3,000 workmen. To keep in good order this congre gation of men, composed of Americans, Germans, Englishmen, and Russians, a company of soldiers is alway's stationed at the manufactory, and a special body of police is appointed to attend there. Men of turbulent conduct, if foreigners, are dismissed at once on any grave contravention of the regulations; and if Russians, they are tied up to a triangle and whipped with the knout. Messrs. Eastwick and Harrison have several times protested against this mode of punishment but unavailingly. Submerged Side Propellers.-We observe in the last American papers, a notice of the launch of a steam-packet ship, called "The Virginia," which is stated to be fitted with submerged wheels, one on each side, near the keel, with engines of from 60 to 70-horse power. The vessel is 150 feet in length, 23 feet 10 inches in breath of beam, has four masts, and will carry 353 tons of goods: and, on an experimental trip, before the masts were rigged, with a full cargo, she averaged nine miles and a half per hour. We presume the wheels are on the horizontal plan, and similar to those lately patented in England by Mr. W. H. Taylor. Were that beautiful invention, called the Archimedean Screw, more justly appreciated, many of these objections would necessarily vanish. = EXPERIMENTAL TRIALS IN PROPELLING WITH PADDLES AND SCREW. 297 EX PERIMENTAL TRIALS IN PROPELLING WITH PADDLES AND SCREW, MADE AT PORTSMOUTH BY H. M. S. V. BEE, 22ND SEPT.-8TH OCT., 1845. THE PRINCIPLES AND PRACTICE OF DRAINAGE. [During the last Session of the Institution of Civil Engineers, a very valuable paper by the President, Sir John Rennie, was read, containing a historical and descriptive account of the Ancholme Drainage in the county of Lincoln-a most successful, but prodigiously protracted work, no less than 556 years having elapsed since it was first commenced. The modern and most important portions of the works have been completed under the direction of Sir John Rennie, assisted by Mr. Adam Smith. After the reading of the paper the following discussion on it took place.] Mr. J. OLDHAM bore testimony to the success of the works of the Ancholme drainage, in the beneficial effects they had produced in the district. Sir JOHN RENNIE said, it would be observed that in the paper he had brought prominently forward, some leading principles of drainage, which he thought were very important. These were, 1st. The formation of " catchwater" drains, which separated the highland from the lowland waters, and conveyed each to independent sluices, at the lowest practicable outfalls. This system was, he believed, first practised by the late Mr. Rennie, about the year 1801, in the Witham drainage. 2nd. The straightening, deepening, and general improvement of the main river, separating, as much as possible, the navigation from the drainage; and 3rd. The formation of over-fall weirs and reservoirs, for arresting the sand and mud, and preventing the drains from being choked. The advantages of these plans must be evident, particularly for a flat district, surrounded by high lands. He was of opinion, that the defects complained of in the Bedford level, might be attributed, in a great degree, to the neglect of these principles, and the continuance of the old Dutch plan, of simply cutting a series of straight drains to the nearest point in the river, without sufficient regard to the outfall, where only as much of the water was discharged, as was allowed by the time the sluice gates could be permitted, on account of the tide, to remain open. This plan alone was, he believed, still pursued in Holland. The attempts to drain the Pontine Marshes, under Pius VII., had been conducted on that principle, and even M. Prony, who was sent to Italy by Napoleon, for the purpose of reporting on the drainage of those marshes, made no other suggestion. It had been asserted, that the Carr Dyke, which was constructed at the foot of the high lands between Peterborough and Lincoln, had been intended, by the Romans, for a "catch-water" drain and for a canal; but there was not any distinct evidence of the fact. The works of the Nene Outfall, which were executed under Mr. Telford and Sir John Rennie, had cost about 160,000l. By that great work, the low-water mark had been lowered 10 feet 6 inches, and in conjunction with the North Level drainage works, which were executed under Mr. Telford, nearly 200,000 acres of land were most effectually drained, which, previously to that time, had been almost without cultivation. A further example of the effect of drainage, might be given, in the Thorney estate, of 20,000 acres, belonging to the Duke of Bedford. It was stated, that at times, previous to the drainage, scarcely any rent had been paid; but now, in consequence of the improvement of the land, from the system of drainage, towards which his Grace had contributed about 100,000., an annual rental of nearly 25,000. was paid. The navigation of the Nene up to Wisbeach, was also so much improved, that large vessels now arrived there, and the trade had been nearly trebled. At Sutton Bridge, about eight miles below Wisbeach, where previously, only moderate-sized colliers could arrive, even at spring tides, vessels of nearly 700 tons burden could now be brought up, at ordinary spring tides. The flow of the tide, which formerly seldom exceeded between 11 feet and 12 feet, now attained a height of upwards of 21 feet, besides securing at low water a depth of between 5 ft. and 6 ft. in the channel down to the sea. Mr. R. STEPHENSON said, that the system of "catch-water" drains would not be generally applicable in Holland, on account of the flatness of the country, there being little high land, except near Utrecht. Sir JOHN RENNIE thought the Dutch, with all their talent and patient industry, had been somewhat too strongly attached to their old plans. In his opinion, if they had done more by warping on their coasts, they would have succeeded better, and would have saved much expense of embanking. Mr. GILES thought the "catch-water" drains indispensable for all well-laid-out plans of drainage. It was also essential to establish the outfall at the lowest practicable point, and to place the cill of the sluice at about 2 feet below the low-water mark of ordinary spring tides. This was much wanted in the drainage of the south and middle and Bedford Level, wherein, if the outlets were carried to below Lynn, the depth of the drainage would be increased nearly 6 feet, and little or no pumping, even for the lowest fens, would be required, throughout the district. THE PRINCIPLES AND PRACTICE OF DRAINAGE. Mr. J. SMITH (Deanston) did not consider the drainage of the middle Bedford Level sufficient for cultivation; the water should be drawn to at least 4 feet beneath the surface. He admired the principles insisted upon in the paper; the combined effects of a straight and capacious main river, with the "catchwater" drains, must be advantageous. It would be practicable, also, to make use of the power of the high-land water collected in the "catch-water" drains, for working water-wheels, either for draining the lower fens, if any existed, where natural drainage was impracticable, or for other useful purposes, either of agriculture or manufactures. He thought, that the cill of the outlet sluice should be placed more than 2 feet below the low-water mark, as the greater the cubic content of the outlet drain, the greater would be the quantity of water discharged, in a given time, and the greater would be the freedom of the discharge. In the fen districts, the ground ordinarily was so flat, that if the cill was only 2 feet below low-water mark, it would be difficult to reduce the level of the water to 4 feet below the surface, which he must contend for, on behalf of the agriculturist. Sir JOHN RENNIE explained, that at Ferraby sluice, the tide in the Humber rose between 26 feet and 28 feet, and he had found, practically, that the cill was placed so low, that the farmers in the lowest and the most distant parts of the fen, were quite satisfied with the extent of the drainage. Mr. J. SMITH (Deanston) said, that possibly the farmers were satisfied, because the present state of the district was so much superior to its former condition; but if the level of the water was reduced still more, they might perhaps be better satisfied. With respect to the overfall weirs and reservoirs for arresting the sand and mud, there was no doubt of their actual utility, and every district would be improved by their introduction. In the present system of surface drainage, large quantities of the lighter particles of the soil were carried by the water, along the open furrows, into the drains ; thus filling them up, and at the same time depriving the fields of their soil. This would, however, be in a great degree prevented, when subsoil drainage was more extensively introduced. The surface of the land would then be so arranged, that the rain would filter through into the drains, and it was now found, that even in very rainy seasons, the water from subsoil drains was but little charged with sand, or earthly particles, and that it could be used for many purposes, for which the drainage water had previously been unfit. 299 Mr. GILES must contend, that there was no necessity for placing the cill of the outlet sluice lower than 2 feet below low-water mark. It was not possible to drain to below that point by natural means; and no extra amount of discharge would be obtained by going deeper. But, on the other hand, there would be a considerable deposit of silt against a cill placed deeper than 2 feet, and the gates would be prevented from shutting accurately. Mr. J. WALKER said, although it was true that natural drainage could not be carried below low-water mark, yet in order to drain down to that level, the cill of the outlet sluice should be placed as much lower as was practicable. It should be recollected, that the gates only remained open for a short time, during which period it was desirable to discharge as much water as possible; then as the quantity passing through the gates, could be appreciated by multiplying the depth of 2 feet down to the cill, into the width of the opening, and by the time the gates remained open, it was evident that if the cill was fixed at 6 feet or 8 feet below low-water mark, the greater depth, multiplied into the same width, would give a greater sectional area, for the passage of the water, in the same time. The friction of the water would also be less when flowing in a mass of good depth, than when it ran in a comparatively thin stream over the cill. There was one point in Sir John Rennie's excellent paper, which Mr. Walker would particularly notice. He could not admit, as a general principle, the propriety of giving to the bottom of the main drains, an inclination of 4 inches per mile from the outlet upward; as in a considerable distance, the depth of the main drains would be so diminished as to materially injure the lateral drainage. He was an advocate for the bottom of the drain being quite level, and at the extreme end, from the outlet, in proportion as the extent of the lateral drains decreased, the width of the main drain might be diminished, but the depth should remain the same throughout its length. The efficiency of the drainage did not depend upon any velocity given to the water by the rise of the bottom, which was virtually so inconsiderable, that the water was sluggish or even almost stagnant. It was, however, much affected by the body of water which was pounded up, at an uniform depth, in the whole length of the main drain, and which acquired a velocity, due to its own gravity, immediately the outlet-gates were opened, and in travelling along, it carried away any silt which might have been deposited in the drain, or at the cill: for it must be remem bered, that the operation was repeated every tide, thus leaving only a short time for the deposition of silt. His experience, therefore, led him to believe, that the outlet-cill should be laid at 6 feet or 8 feet, below the level of the low-water mark, of the lowest spring tides, in order to produce the utmost effect. The overfall weirs and reservoirs, were, he thought, good precautions, as they materially decreased the necessity for frequently cleansing the drains. With respect to the question of the sepa ration of navigation from drainage, to whoever the credit of the introduction belonged, there could not be any doubt of the correctness of the principle. He had insisted upon that system, in the drainage of the Middle Level, and it would be there carried into effect to a greater extent than, he believed, in any other district, and he would have an account of the works prepared for the institution. In that district, in a distance of 30 miles, there was only a rise of 18 inches, so that a level main drain was indispensablė. It was somewhat extraordinary, that there was so little known of the history of the embankment of the river Thames, which, whether examined with respect to its extent or efficiency, was equally remarkable. It was generally attributed to the Romans, and there was every reason to believe, that it was owing to the sound principles upon which the works had been commenced, that they had been enabled to be continued and kept up since in their present state.* It would be observed, that the land on both sides of the river, beyond the bank, was 7 feet. beneath the level of ordinary spring tides, and 10 feet below that of the extra spring tides. The action of the tide had caused the formation of a fore-shore against the banks, which materially assisted them. In short, the embankment of the Thames was, perhaps, the 'most useful work the Romans had executed in this country, and if they exhibited such a practical knowledge of hydraulic works in one instance, it might be presumed, that they had constructed the Carro dyke, with the intention of its serving as a 66 catchwater" drain, for which its position evidently fitted it. It was not always practicable to establish such drains, but wherever they could be formed, there could be no doubt of their advantage to a system of drainage. * Vide Dugdale's History of Embanking and Draining; 2nd edition, by Cole (folio; London, 1772); and Cruden's History of Gravesend, p. 23 (royal 8vo; London, 1843.) This latter work contains very good information on these interesting labours of the Romans, and on the present mode of keeping them up. Mr. J. SMITH (Deanston sirable to place was decidedly of opinion, that if was the cill of the outlet sluice 2 feet below lowmark, it would be more advantageous water cert as much as 8 feet below. The great point to be attained, was the freedom of discharge, which would be more readily accomplished, by having a considerable column and great cubic section, than by attempting to obtain great velocity. The silting up, would be more completely obviated, by a considerable mass of water, than by the passage of a less stream, at a greater velocity. The practicability of obtaining a level main drain, must depend, in some degree, on the nature of the district and the height of the surface of the land. There could not be any doubt of the advantage of giving ample depth of water, and it was decidedly preferable to diminish the width, rather than the depth of the upper end of the drain, particularly in very flat districts, where, in an extent of many miles, there was not more than 3 feet, or 4 feet fall, from the upper point to the outlet. Mr. FAREY said, that the opinion expressed by Mr. Walker accorded, in a remarkable manner, with that of Smeaton, as recorded in some of his unpublished MSS., from which he had extracted the following passages Deeping Fen Drainage. Letter from Mr. Grundy to Mr. Smeaton, dated "I have taken the levels and surveys; it is a tract of near 40,000 acres, and its uppermost extent, from its proper outfall, near 16 miles, and in breadth 6 miles. Preparatory to forming a scheme for the more perfect drainage of Deeping Fens, near Spalding, I am ordered, by the adventurers of Deeping Fens, to confer with our brother Tofield on the subject matter of draining these fens. As we have made separate reports without any communication with each other, it is no wonder there are some differences in opinion, but one point we cannot reconcile, and therefore have agreed to refer the matter to you. Mr. Tofield recommends digging our drains and rivers to a dead level, or horizontal bottom, from the outfall to the lowest lands to be drained. My opinion, as well as practice is, to form them into one inclined plane, parallel with the mean surface of the country through which they are cut, by which method much expense in digging is saved, and, as I conceive, equally eligible." From Mr. Tofield, dated March 8th, 1770. "I had a conference with your friend Mr. Grundy at Retford, upon the subject of |