FORBES' SHIP LIFE-BOATS. After the meeting, Mr. Doull, jun., exhibited a model of, and described a system, proposed by Mr. James Forbes, for lowering and raising ships' boats, and also the construction of a Cylindrical Ship Life-Boat, which latter, it was contended, approached nearer, than any other construction, the combination of the qualities considered requisite for a boat of that class. The Cylindrical Life-Boat was 30 feet long, 8 feet wide, and 2 feet deep, when opened out; it would carry, with ease, sixty persons, with provisions for a week, in the air-tight seats,-could not be upset, or swamped,-could be pulled either end foremost, was steered with an oar,-had extra buoyancy in watertight compartments, and was só constructed, that a hole might be knocked into one, or more divisions, without danger to the whole, and was fully stowed with masts, sails, oars, and everything complete, so as to be always ready for use, on any sudden emergency. When folded up, it was perfectly cylindrical, and on reaching the water it opened out, and could, in a minute, be made a stiff boat; and the dimensions could be modified to suit any vessel. The cylindrical form, and its lightness of construction, would enable a boat of this sort to be put over the bulwarks by six men, without tackle of any kind, and by merely cutting a lashing when in the water, it would fall open, when all the stores, &c., would be found made fast within, and ready for use. The apparatus for lowering boats consisted of two davits, with tubular stems, down which the ropes passed, through sockets in the bulwarks, to a drum on which they were coiled, so as to be easily wound up by a wheel and pinion, with the exercise of very little power, and in lowering, a friction-break could be used with great advantage. By this means the boat would swing out very easily, as the davits could turn entirely round, and it would be nearly impossible that a boat could be swamped, in the heaviest sea, or under circumstances of the greatest difficulty. November 23, 1852. JAMES MEADOWS RENDEL, President, No. 880. "On the Drainage of Towns." By ROBERT THE Drainage of Towns is so comprehensive a subject, that its full and complete treatment, within the limit of a communication to be read at one evening meeting, would be a useless attempt; the object of the present paper, therefore, is restricted to furnishing topics for a discussion, during the course of which, it may be anticipated, that the merits, and demerits, of the different systems of sewerage, will be fully developed and freely canvassed. Town drainage may be considered historically, politically and socially. The historical portion of the question need not be entered into, further, than to say, that remains of what appear to have been drains are found in the long-buried cities of Syria, and the sewers of ancient Rome partake of the fame of "The Eternal City;" indeed the Cloaca Maxima is asserted, by some authors, to have been the work of a people older than Romulus. Livy, however, gives the reign of Tarquinius Superbus, as the date of its formation. Politically-the question of the best system of town sewerage and of house drainage, is very urgent, and at no period has it ever been of greater importance, than at the present time. It may be clearly shown, that the progress, if not the permanence of civilization is dependent upon a correct appreciation of its merits; as the healthy existence of town populations must ever be influenced by their sanitary condition. Misery, pauperism, vice and crime find a forcing-bed in the unsewered parts of towns, and amidst the foul air of undrained houses. The discussion upon this Paper extended over portions of four evenings, but an abstract of the whole is given consecutively. * Drainage and sewerage, as connected with towns, are treated in this paper as synonymous. Sewerage is, probably, the proper term, as applied to towns, and drainage to the country. This may not be self-evident, on a cursory consideration, but facts and figures, which will not admit of contradiction, can be brought in aid of the assertion. The tendency of modern civilization has been to congregate the human race in masses, and in Great Britain, the extension of towns is unprecedented. In 1841 the population in one hundred and seventeen districts, comprising the chief towns was 6,612,958 souls. In 1851 in the same districts the number was 7,795,882, being an increase of 1,182,924 in ten years. When it is remembered, that the greater portion of the area, thus populated, is comparatively low and flat; such as in seaports, on the banks of inland rivers, or in valleys intercepted by canals, it is not surprising, that this crowding should produce disease, as is proved by the almost constant presence of fever, and a recurrence of the more deadly cholera. It is quite true, that disease, in some terrible form, or other, has ever been associated with man, when thickly congregated, whether in cities, in towns, or in armies-but it may also be shown, that much of this disease has been of that class, which, by due precaution, might have been averted. A full elucidation of this portion of the subject, belongs rather to the medical department, than to that of Engineering; it may, however, be stated, that the averages of mortality, though much higher in town, than in country districts, do not reveal the worst feature of the case, as the annual number of deaths, in the most unhealthy parts of a town, are frequently as ten to one, compared with the better parts of the same town. That is, if ten out of each thousand die annually, in one district of a town, one hundred out of each thousand perish, in another quarter of the same place-so that a statement, of any given average of deaths, per thousand, would be liable to mislead. The average number of deaths, in English towns, ranges from twenty to thirty per thousand. In country districts, the average does not exceed seventeen, or eighteen, per thousandand amongst the well-regulated classes, only about ten to fifteen deaths, per thousand, occur annually. In the convict prison, on the Isle of Portland, the annual average of deaths is only about five per thousand. There are, however, in that establishment, neither infants, nor very old people, to swell the mortality. This portion of the subject may be closed, by a quotation from a valuable Report, on Cholera in England, recently issued by the Registrar-General, in which he says:-" A large por"A tion of the next generation of Englishmen will be born in town-districts, some of which are high and healthy, while others low, insalubrious, subject to inundations and to the incursions of cholera, present many of the circumstances in which a degradation of race is inevitable. In the dense districts of Lancashire, where the health of parents is depressed, and the circumstances are often so prejudicial to their offspring, that, of the coming generation five, instead of two, of every ten born, are destroyed in the first five years of life, and the survivors, with a few happy exceptions, are left with shattered, feeble, febrile and disorganized frames-degeneration is as inevitable, as the degeneration of horses, oxen, and sheep, in circumstances equally unfavourable." The might of a nation consists in the health and strength of the peopletherefore the supremacy of a country is, in a degree, dependent upon its general sanitary condition. It is, however, to the social effect of town drainage, that the attention of Civil Engineers will be most naturally directed, as under that head, the leading principles of actual practice, and those modifications which have been proposed for adoption, must be brought forward and discussed. So much has been recently said and written upon town drainage, that it will be quite impossible to strike out either a new, or an independent course, nor is it advisable to do so, as to study precedent,—to learn from experience, and to correct from practice, are the chief duties of an Engineer. The much-disputed question of, "in what good town drainage consists," can only be answered by the exhibition of actual works, which do fully answer their intended purpose. The forms and dimensions of sewers, the materials of which they may be constructed, and the depths below the surface at which they should be laid, admit of some moderate difference of opinion; but certainly not to the extent, now permitted in practice. In one position a brick sewer 5 feet high by 3 feet wide will be constructed, at about £2 108. per lineal yard, whilst in a similar situation, there will be laid down an earthenware tube, 1 foot 3 inches in diameter, at an expense of 8s. or 10s. per lineal yard. There must be something positively wrong in such discrepancy of practice as this, and the sooner the truth is discovered and proclaimed, the better will it be for all parties. If that man is a benefactor to his race, who makes two blades of wheat grow, where one only grew before, he is likewise so, in a degree, who constructs two lineal yards of effective sewer, for the price that has before been expended upon one yard; if the cheaper sewer performs its functions more, or even as, perfectly, then is the achievement so much the more worthy; but if it does not perform so well, then the innovation becomes an injury. It has been asserted, that no street sewer ought to be less than will allow a man, or a boy to pass along it. The Legislature has passed an Act to prevent boys being sent up chimneys, and, better arrangements being made for providing water for flushing, it may, some day, be inclined to pass an Act to prevent men from entering sewers. The latter will be more humane than the former; as, it is asserted, that more lives have been destroyed in foul sewers, than ever were lost in crooked chimneys. In town drainage there are three primary considerations: 1st. The line for the outlet sewer, or sewers, if more than one such be necessary. 2nd. The dimensions of these outlet sewers, and their form. 3rd. The materials of which sewers may best be made. The position of the outlet, or outlets will in some measure be governed by natural conditions. They must be in such a relative position as shall least endanger health; and wherever it is practicable, only one outlet should be formed, as the refuse will then be concentrated, either for natural removal, or for agricultural use. The size of outlet-sewers must be fixed by the number of houses to be drained, and the extent of the area upon which they stand. The site to be drained may consist of flat alluvial land, impervious mud, or pervious gravel shingle; or the town may stand on the banks of a tidal river, the surface being very little above the high-water line, or it may be actually below the |