360 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



[October, 



immense blocks of stone, contributing to bind the whole together, will 

 then be laid upon it, beginning as far beneath the sand as practicable, 

 and continued full twelve feet above high water mark, and upon this 

 the shaft will be raised, the whole superstructure being left to the skill 

 and taste of the engineer. I have only to add that the expence of the 

 wells, however numerous they may be, will be comparatively trifling, 

 and wholly unworthy consideration, taking into account the vast im- 

 portance of this truly national undertaking. 



M. 



ENGINEERING IN IRELAND. 

 Improvement of the River Shannon. 



g IR _I shall feel obliged by your inserting the enclosed paper, re- 

 ferring to a portion of the extensive improvements which are in pro- 

 gress in the river Shannon, in the forthcoming number of the Journal. 



I forward with it a small plan of the site, shewing the weir A. B., 

 and describing (by dotted lines) the three large portions into which 

 the works were divided by dams, for the convenience of their execu- 

 tion. I am > Sir i 



Killaloe, County of Clare. Your obedient servant, 



4M Sept. 1843. Thomas Barton", 



Resident Engineer. 



Scale, 800 ft. to an inch. 

 Reference. 

 C. C County ot Clare. C. T., County of Tipperary. A. E., The Weir. 

 The budge which crosses the river leads from Killaloe, county of Clare, to 

 Ballena, county of Tipperary. C, canal. 



On Tuesday, 15th August, Lieut. Col. Harry D. Jones, R.E., Shannon 

 Commissioner, and Thomas Rhodes, Esq., principal engineer, accom- 

 panied by William Mackenzie, Esq., the contractor for many of the 

 important works on the line of the Shannon, arrived at Killaloe, and 

 on the following day, inspected the works which are in progress in 

 that beautiful neighbourhood, and are fast verging to completion ; 

 after which Col. Jones proceeded on his periodical tour of inspection 

 to the works in the Lower Shannon ; having previously visited the 

 Sc.irriff River, where an improvement is carrying on that is likely to 

 be of the utmost advantage to the Towns of Scarriff and Touryvaney, 

 and to a very extensive agricultural district surrounding them. 



On Tuesday (22nd ultimo) the gallant Colonel returned to Killaloe 

 for the purpose of witnessing on Wednesday, according to arrange- 

 ment, the admission of the water to that part of the great regulating 

 weir, which had lately been completed, but Old Shannon, grown impa- 

 tient, would no longer be held in artificial bonds, and bursting forth, 

 resumed his dominion, sweeping with magnificent and easy flow along 

 the improved level of his bed, and thus anticipated the spectacle in- 

 tended to have taken place on Wednesday. 



In October last, a portion of the weir, on the Clare side of the river, 

 amounting to GOO ft. in length, had been finished, and the water being 

 turned over it, dams were made, and the Tipperary side of the river 

 was laid dry for the purpose of reducing the shoal, and constructing 

 the remaining portion of the weir, during which operations the river 

 had been confined to a channel of one half its usual capacity. 



The Shannon, at Killaloe, now flows over a line of weir 1100 ft. in 

 length, and it is anticipated that this erection will effect a very con- 

 siderable permanent reduction of the winter flood, and solve the prob- 

 lem (somewhat difficult to be understood by persons not conversant 

 with the laws of fluids in motion, but which is clearly appreciated by 

 the hydraulic engineer), that a Bar or Weir may be constructed across 

 a river in such a manner as to obtain an increased discharge. 



There is in the apex at the weir, a small deviation of level at one 

 period, so formed as to assist in the annual migration of the salmon, a 

 deep pool being constructed at the foot of the weir, opposite this 

 point, for the purpose of facilitating the leaping of the fish, and at the 

 termination where the weir adjoins to the rock on the Tipperary side, 

 there is a roughly formed inclined plane, by which the young eels, 

 spawned in the estuary, will be enabled to climb the summit of the 

 weir, and pass into the upper waters. 



Leaving the question of navigation untouched, some notion may be 

 formed of the improvement likely to result with reference to drainage 

 only, when it is stated that the maximum height of floods at Killaloe, 

 have been known to attain to 9 ft. above the level of the apex of this 

 weir, and that hereafter their utmost height will scarcely surpass 

 three feet above the same datum. 



It must be a source of peculiar gratification to Mr. Rhodes, the 

 commissioners' principal engineer, to see, after years of unceasing 

 study and anxiety, that his arrangements are attaining completeness, 

 and evincing success such as could only follow the workings of a 

 genius like his, so particularly fitted to this abstruse branch of the pro- 

 fession, and of which Lord Stanley, (then the Rt. Hon. E. G. S. Stanley) 

 seems to have been so well aware, when, in 1S31, he directed this 

 eminent gentleman's attention to The Shannon.' our own Shannon.' 

 the dominant stream of Ireland, and the pride of British rivers ! 



T. B. 



REVIEWS. 



Illustration* of lh Crohn Auuiduct. By J. B. Tower, of the 

 Engineer Department, (U. S.) Wiley and Putnam, New York and 

 London, 1843. 



We have here* an elaborate memoir of one of the greatest works 

 of our Anglo-American brethren, a work entailing an expence of up- 

 wards of a million sterling, and of that colossal character as to take 

 a high rank among the triumphs of engineering science. It is one of 

 those works which the people of English race on both sides of the 

 Atlantic can look upon with equal pride. We have no doubt that the 

 elaborate and extensively illustrated volume of Mr. Tower will be 

 acquired by many of our readers no less as a record of the Croton 

 aqueduct, than of the high standing which the engineering profession 

 has taken in America, and of the way in which its reputation is 

 mentioned. To do adequate justice to it, it would be necessary to 

 give several illustrations, and we hope at some future time to be able 

 to do this. We make the following extract, to show the reason why 

 the aqueduct form was adopted. 



" Having fixed upon the Croton River as a stream possessing the requisite 

 advantages for a supply, questions naturally arose as to the manner in which 

 it should be conveyed to the city. The distance being ahout forty miles, OTer 

 a country extremely broken and uneven, and following a direction for a por- 

 tion of this distance, parallel with the Hudson River, encountering the 

 streams which empty into it and form deep valleys in their courses. It will 

 be interesting to notice the different plans which were suggested for forming 

 a channel-way to conduct the water. The following modes were presented: 

 — a plain channel formed of earth, like the ordinary construction of a canal 

 feeder : — an open channel, protected against the action of the current >>y 

 masonry: — an arched culvert or conduit, composed essentially of masonry, 



