1846.] 



THE CIVIL ENGINEER AND ARCHITECPS JOURNAL. 



353 



for allowiog any surplus to flow into the Thames witliout going back into 

 the sewer ; at the same time that the company confidently anticipate, after 

 the farmers shall have had experience of the value of the manure, that the 

 demand will be greater thau the supply. The supply is calculated at 

 60,000,000 tons annually, producing, at 2d. per ton, an income of 50,000/,, 

 which would leave above the outlay a net profit of 13,000(. on an estimated 

 expenditure of 120,000/. It will require 2S,000 acres to consume the 

 60,000,000 tons, of which it is expected that two-thirds will be taken for 

 the irrigation of meadow, and one-third for the enrichment of tillage land. 

 As the process of pamping will be conducted in a closed building, so con- 

 structed as to carry any foetid exhalations that may arise from the water 

 during the short period it is exposed to the atmosphere, into the furnace of 

 the steam engine, there to be destroyed, the committee arrived at the con- 

 clusion, not only that this station-house will be unobjectionable, but that 

 by the proposed means the liquid will be removed in a far less ofl'ensive 

 state than that in which it is now found, when backed in the open sewer 

 by the high tide, and stagnating for hours together in the immediate vicinity 

 of a thickly inhabited district, to be subsequently poured forth at low tide 

 into the open bed of the river. The only remaining danger or inconvenience 

 to be apprehended was from the breakage of the pipes or the ultiniats dis- 

 tribution of the water upon the land ; but as it had been clearly established 

 in evidence, first, that sewage water is not corrosive in its nature or liable 

 to generate explosive gases, and next that its distribution is not attended 

 with an ofl'ensive effluvium unless in hot weather, when, owing to its rapid 

 absorption into earth, the unpleasantness is of very short duration, the 

 committee had no hesitation in believing that it may be as safely conveyed 

 in iron pipes as the water of the Thames is at present by the several com- 

 panies who supply the metropolis ; and that in its application to the land 

 it will be less ofl'ensive than manure in i(s solid state. The report contains 

 some very interesting evidence from scientific men, supported by that of 

 skilful farmers, and showing, that under an improved system of husbandry, 

 by the application of the science of chemistry to that of agriculture, the 

 soil, no matter what its nature or locality, may be rendered by many de- 

 grees more productive and more profitable. A minute chemical analysis 

 of the sewer water of London, besides being unintelligible to the general 

 reader, would be out of place in a mere abstract. All capacities, however, 

 can understand the result, as given in the evidence of Mr. Miller, Profes- 

 sor of Chemistry in King's College. He found in it considerable portions 

 of amraoniacal salts, alkaline salts, and earthy phosphates, substances 

 which are found in the soil in only small quantities, but which are never- 

 theless absolutely essential to the maintenance of vegetable life. These 

 ingredients are principally derived from the ashes of our bodies, resulting 

 from the food we have digested ; and as we have received them either di- 

 rectly from plants, or indirectly through animals from plants, it is evident 

 they must be the food of plants, and that plants receive them from the soil, 

 which they gradually exhaust. Mr. Miller stated also this curious fact — 

 that the money value of those ingredients as poured into the Thames from 

 the King's Scholar's Pond Sewer alone, assuming that the quantity falling 

 from that sewer is 12,000 tons a day, amounts to no less than G2/. every 

 twenty-four hours, or 22,030/. a year. The report likewise contains much 

 useful information derived from the experiments of practical men in the 

 application of sewage water to land, showing in all instances that it pos- 

 sesses a much greater fertilising power than either guano or the ordinary 

 farm-yard manure. A Mr. Thompson, of Clitheroe, in Lancashire, on ap- 

 plying eight tons of it to one acre, fifteen tons of common manure to another, 

 and three cwt. of guano to a third, found that the grass raised by the sewage 

 water, compared with the quantity produced in the other two cases, was 

 as fifteen tons against eight. The Duke of Portland is stated by means of 

 the sewage water of Mansfield, and a cost of 30/. an acre for bringing the 

 land into a proper form for irrigation, to have raised its value from 4s. Gd. 

 to 14/. an acre. Mr. Dickinson, au extensive keeper of horses, by the use 

 of liquid manure derivtd therefrom, got ten crops of Italian rye grass in 

 twelve months, some of them more than three feet high, out of land (on his 

 farm atWillesden, near London), which a Lincolnshire man had previously 

 said he would not give 12s. an acre for, if at his own door; and which a 

 Norfolk man declared he would not farm as a freehold. Speaking of the 

 present year, Mr. Dickinson stated, that the first crop was cut in January, 

 yielding more than four tons an acre, (hat the second gave about double 

 that, and that the fourth, which had been cut in the month of June, had 

 produced at least twelve tons an acre. From his calculations it appeared 

 that one horse supplied sufficient manure for one acre ; and when pressed 

 for a direct opinion upon the subject, he replied, that he had no doubt 

 whatever that every animal that lived, by his refuse being economised, 

 would produce more than he could consume. This is an important fact 

 for the agriculturists, especially at the present moment, and it is to be 

 hoped they will not lose sight of it, but endeavour, like Mr. Dickinson, to 

 make their land more productive, and thereby not only benefit themselves 

 and the country, but materially serve tlie cause of science 



Fall of Railway Bridges, Embankments, kc. have occurred at numerous 

 places. At Aberdeen, several arches of the inclined plane ; between Lin- 

 ton and Dunbar, three bridges ; on the Tynemouth Extension line, three 

 yaads of tunnel ; on the Newbury line, several bridges ; fifty yards of cut- 

 ting on the iiiighton and Hastings line. 



PORT OF DUBLIN. 



Improvements of the Gr.\nd Canal Docks at Ringsend. 



flfith an Engraving, Plate XVII.J 



Among the chief commercial interests of the city of Dublin is the extensive 

 trade of the Shannon and the Grand Canal. The enlargement of the canal 

 docks has therefore been long considered a subject of great mercantile im- 

 portance, and from a Report of Sir John Macneill, now before us, there ap- 

 pears every probability of this great improvement being speedily effected. 



The principal features of the undertaking are the formation of a new Tida 

 basin, the diversion of the river Dodder and the construction of a new en- 

 trance to the Floating and Graving Docks. The task of preparing a design 

 for effecting these objects has been confided to Mr. McMcllen, and has 

 been performed in the most simple and satisfactory manner. The plan pro- 

 posed by Mr. McMuIlen is made the subject of a warm eulogium in Sir J. Mac- 

 neill's report, which speaks of its extreme " simplicity," and the " extraordinary 

 facilities which every where exist for carrying it into execution." The 

 following extracts from the Report, and a reference to the Plate XVII. will 

 sufficiently explain the nature of the proposed improvement. 



It is impossible to cast the eye over your Company's splendid Floating 

 Basin, covering, as I understand, twenty-five statute acres, with a depth of 

 water which I find is now steadily maintained at 18 feet or thereabouts, 

 without a feeling of great regret, that facilities, such as are thus afl^orded, 

 both for the foreign and coasting trade of the port of Dublin, and the im- 

 portant adjacent districts, should not be as available for the advantage of 

 that trade as they unquestionably can be rendered ; and for the accomplish, 

 ment of this most desirable object, I freely admit that I have seen no project 

 or plan at all comparable to that now before me, either as to the extent of 

 the advantages which it is calculated to secure, or the comparatively small 

 cost at which it is capable of being executed. 



Of the several operations which the carrying out of the project involves, 

 there is none the necessity for which is so manifest, or the cost of which 

 would be so trifling, compared with its importance, as the turning out of the 

 Dodder upon the South Bull. An enormous deposit is carried down and 

 lodged in the channel opposite the entrance to the docks. The dredging 

 out of the narrow, and as yet quite inadequate channel, forming the ap- 

 proach to Camden and Buckingham Locks, and of that portion of the rivei 

 immediately opposite, has, this year, as I am informed, occupied the two 

 powerful steam dredgers of the Ballast Corporation, for a period of about; 

 two months, at an expense which cannot but be very heavy, and which must 

 recur annually, and inevitably after the winter floods, as long as the river 

 is allowed to remain ia its present course. The necessity for an improve- 

 ment so obvious has been long felt. I find that it was recommended by the 

 Irish House of Commons on various occasions, and attached to their pro- 

 ceedings of the date of 26th February, 1785, there is a ground plan of the 

 new course into which it was proposed the river should then be turned, 

 which scarcely at all differs from that laid down in the present plan. And 

 this was further followed up by the enactment contained in the act, creating 

 the present Ballast Corporation, by which the directors of that corporation 

 are authorized to carry out and complete the measure. In accomplishing it, 

 there is no actual necessity for the removal of the present weir, although 

 this would render the results more useful to the adjacent grounds, and in 

 this case a supply of water to the neighbourhood could be readily obtained 

 from the river above Ball's bridge, and a reservoir formed on the site of the 

 mill-pond of the old distillery, as sketched on the plan. I have examined 

 the ground which it is proposed the new course should occupy. In length 

 it is about 600 yards. 



An apprehension has, as I am informed, been expressed in some quarter, 

 assumed to be entitled to attention, and in this way brought under your no- 

 tice, to the effect that the sand, carried down by the river, and which, in the 

 event of the proposed change of its course, would be deposited on the south 

 strand, might possibly be drifted across the Bay towards the entrance of 

 Kingstown harbour, and produce inconvenience or obstruction there. Such 

 a result I consider to be altogether out of the question, and the anticipated 

 suggestion of it, destitute of the slightest rational foundation. 



In turning to the plan for the formation of the Tidal Basin, it is impossi- 

 ble not to be struck with the fact, and it is one of manifest importance, 

 namely, how much of the work has been already done, and how little, for 

 the realization of the whole project, remains to be accomplished ? while of 

 this latter, the entire is of the plainest, every-day character, and quite free 

 from any thing which could be regarded as an engineering difiiculty. The 

 whole is in fact comprised in the excavation of the ground, the extension of 

 the present south quay wall, the lining of the interior with cut-stone facing, 

 well puddled, and the constractiou of the entrance gates. The proposed 

 Lock for the admission of steamers of the largest class to the upper basin 

 does not appear so indispensable to the successful working of the plan, as to 

 call for its being immediately undertaken. It may be prudent to wait the 

 result of the trials of the screw propeller now in progress, and in the mean- 

 while the outer basin will afford a very large amount of accommodation to 

 the ordinary class of paddle steamers. In reference to the excavation of the 

 basin, it is well deserving of notice, that the ground inside of the Queen's 



46 



