1841.] 



THE CIA IL ENGINEER AND ARCHITECTS JOURNAL. 



23.5 



them to throw up tlieii- frout ends, and thus present their hind ends opposite 

 to abutments formed in tlie face of the carrier, which, coming in contact 

 with the hinder ends of the cogs, turn the paddle-wheel round. In the event 

 of this wheel being struck by a heavj- sea, the blow causes it to revolve faster 

 than the carrier, and thereby relieves it from the injurious effects of the con- 

 cussion. When the force of the sea is expended, the abutments again come 

 in contact with the cogs, and the wheel is driven round by the effects of the 

 engine. A mode of placing paddle-wheels in an incUned position is shown, 

 by wliich means external projecting paddle-boxes are dispensed with. — Ibid. 



IMPROVEMENTS IN STOPCOCKS. 



Henry Bridge Cowell, of Lower-street, St. Mary's, Islington, Middlesex, 

 ironmonger, for improvements in taps, to be used for or in the manner of 

 stopcocks, for the purpose of drawing off and stopping the tlow of fluids. 

 Enrolled June 2, at the Roll's Chapel Office. 



The first part of this invention consists in applying a moveable stopper to 

 the spout of a tap, such stopper being suspended at the lower ends of two 

 upright connecting links, one at each side of the spout, which link pass down 

 through holes or sockets in the metal of the head of the tap. The upper 

 ends of these links are connected to a piece of metal or collar, situated above 

 the head, and fitted around a screw that turns in the same, so that on the 

 screw being turned it will either rise or fall, and consequently raise or lower 

 the stopper, thereby opening or shutting the spout of the tap. The fluid 

 which escapes round the sides of the orifice of the spout on the stopper being 

 lowered will be collected in the hollow mouth of the tap, so as to run out in 

 a compact stream from the lower orifice. 



Tlie second part of this invention consists in applying to a ball-cock (similar 

 in its parts to the tap just described) a second ball and lever, provided with 

 a click or detent, having a tooth, which catches into a notch or notches cut 

 in the circumference of an enlarged head on the end of the screw before 

 mentioned. The click is mounted on a centre pin fixed in the collar of the 

 screw, so that whenever the other ball descends the tooth catches into one 

 of the notches, and turns back the screw, thereby opening the passage through 

 the cock for the wafer. The usual ball is kepc submerged during the flowing 

 in of the water into the cistern, by means of the click preventing the screw 

 to wiiich it is attached from being turned ; but when (he surface of the water 

 reaches the second ball, and raises the same upwards, the click will be lifted 

 up about its centre of motion, so as to disengage its tooth from the notch in 

 the head of the screw, whereupon the other ball will immediately rise to the 

 fop of the water by its power of floatation, and close the passage of the cock. 



The third part of this invention consists of another kind of tap, similar in 

 some respects to the one first described. — The moveable stopper is fitted in 

 the manner of a piston into the cylindrical hollow of the head of the tap, so 

 as to move up and dowu therein Ijy the action of a screw working in a cap 

 that surmounts the head of the tap ; by turning this screw round, the stopper 

 is pressed dowu on the upper orifice of the water-passage of the spout, and 

 at the same time over the annular orifice of a circular channel formed within 

 the head of the tap, and passing round the water-passage, tlirough which 

 channel the water is conveyed to the passage. Thus ou depressing the stopper 

 the flow of water will be stopped, but on raising the same the water will be 

 permitted to flow again. — Inventors' Advocate. 



FROCESDINGS OF SCIENTIFIC SOCIETIES. 



INSTITUTION OF CIVIL ENGINEERS. 



February 23. — M'illiam Cubitt, V.P. in the Chair. 



The fallowing were balloted for and elected : Colonel Sir Frederick Smith, 

 R.E., William Chadwick, John Bazley White, jun., Charles Lorimer Hensman, 

 Joseph Whitworth, and Evan Hopkins, as Associates. 



" Description of a new mode of Steering, as applied to boats of light draught 

 of water, navigating shallow and rapid rivers.'' By Captain Henderson, 

 Assoc. Inst. C.E. 



The ordinaiT method of steering with a single rudder, fixed in the usual 

 manner, will bring a vessel round in about four times its length, upon an axis 

 at the point of union between the dead wood of the vessel and the nidder. 

 It was found desirable for the particular service on the Ganges and Burham- 

 pooter, for which the vessel in question was designed by the Assam Company, 

 that great facility should be given for coming round rapidly ; to accomplish 

 this, the stem and stern of the vessel are alike provided with rudders, of a 

 form adapted to the curvature of the craft. The stern rudder is considerably 

 larger than the other, and occupies the space usually allotted to the dead 

 wood, which is cut away ; a more immediate influence is thus exerted upon 

 the boat. The rudders are raised or lowered according to the draught of 

 water, by means of capstans fixed upon the projecting ends of the shaft of a 

 pinion, which is geared into a tootlied racked of peculiar constnicfion, on the 

 back of each rudder post. The effect of this arrangement is, that the centre 

 of revolution is transferred to a point nearer the centre of the vessel, and de- 



viating from the true centre, in proportion to the relative dimensions, posi- 

 tion and figure of the two rudders, and of the lines forward and abaft the 

 vessel, which is thus brought round in little more than its own length. 



The vessel, of which a model accompanied the paper, is fitted with con- 

 densing engines working expansively, with a pressure of steam of 20 ft. in 

 the boiler ; the cylinders are placed at an angle towards the paddle shafts, 

 and act directly upon the cranks without the inteiTention of side levers. 



'* Description of a Coffre Dam used in excavating Rock from the navigable^ 

 Channel of the river Ribble." By David Stevenson. 



The navigation of the river Ribble being much impeded by natural bars or 

 weirs of sandstone rock, compact gravel, or loose sand, several ineffectual at- 

 tempts were made to remove these hindrances, and eventually a joint stock 

 company, called the Ribble Navigation Company, was formed for that pur- 

 pose. Messrs. Robert Stevenson and Sons (of Edinburgh) were consulted, 

 and under their directions the present works were commenced : their plaa 

 was to cut a channel in the rock wherever it was necessary, and to remove 

 the gravel and sand by steam dredging, forming at the same time a low ndi- 

 ble wall upwards of a mile in length, for the purpose of directing the course 

 of the river so as to obtain a permanent and straight navigable track for the 

 shipping. The first of these operations is alone treated of in the communi- 

 cation. 



About half a mile below Preston, a bed of sandstone rock, upwards of 300 

 yards in length, stretches quite across the river ; some portions are entirely 

 free from any deposit of sand or mud, and the higher parts are frequently left 

 dry during the summer months. This natural weir exerts such an influence 

 upon the flow of the tides, that neap fides which at 12 miles distance rise \t 

 feet, are not at all perceived at the quay at Preston. 



It was proposed to cut a channel through this bar, 100 feet in breadth, 

 affording an average navigable depth of 20 feet at high water of spring tides. 

 In some places, therefore, the excavation woidd be 13 ft. 6 in. deep. After 

 much consideration it was determined to make use of a series of coffre dams, 

 as the most effectual and economical mode of proceeding. Their constnic- 

 fion may be thus briefly described : — 



A. double row of wrought-iron bars, 2V inches diameter, with ji'Kin/;ec points 

 worked upon them, were inserted vertically into the rock at regular intervals^ 

 of 3 feet apart laterally, the second row being placed 3 feet behind the front 

 row. When a suflicient number of bars were fixed, a tier of planking, 3 inches 

 thick, with clasps to enable the planks to be fixed to the rods, was placed 

 withinside. The lower edges of the planks were cut out roughly to the in- 

 equalities of the rock ; they were then lowered, and by means of an iron rod, 

 with a crooked end, those parts which did not touch the bottom were ascer- 

 tained, and a change in the form made, until the plank rested its whole length, 

 on the rock : the lower edge was then bevelled off, and being finally lowered 

 to its place, the plank was beaten down by the force of a heavy mallet, upon, 

 an upright piece of wood resting upon the upper edge of the planks ; the 

 lower bevelled edge yielding to the blows, sunk into the irregularities of the 

 rock, and thus ultimately, in connexion with the puddle behind it, formed a 

 perfectly water-tight joint. The lower planks being fixed, the upper ones 

 were placed upon them ; transverse tie bars were inserted at intervals ; ancE 

 the clay puddle was formed in the usual manner. In order that the naviga- 

 tion of the river should not be impeded, the diagonal stays were all placed 

 inside the dams. These stays had joints at the <ipper ends, and being slipped 

 over the tops of the iron rods, and kept in their places by cotters, their lower 

 ends could be moved either horizontally or vertically, as the irregularity of 

 the rock required : — as the excavation proceeded, longer stays were easily 

 substituted, by merely removing the cotter, sliding up the short stay, and re- 

 placing it by another suited to the increased depth. The sides of the dani 

 were kept together by bars of iron connected to two horizontal wale pieces, 

 10 inches by 6 inches, placed on the outside of the vertical iron rods. When 

 the dam was thus constructed, the water was pumped out by a steam engine 

 of 10 horses power, with two pumps of 12 inches diameter. 



The whole of the excavation, which was 300 yards in length, and 100 feet 

 in width, was to be completed with three lengths of coffre dams, so contrived 

 as to include within the second stretch the lower side of the first dam, in 

 order to excavate the rock in which that row of piles was fixed. The first 

 and second lengths have been most successfully executed; the third is now 

 in progress, and the excavation is proceeding ven' rapidly. The sandstone 

 rock does not require gunpowder. The total quantity to be excavated is 

 estimated at 31,000 cubic yards; all the stone which is raised is used in the 

 construction of the wall for directing the course of the lower part of the 

 river. 



Some doubt e.xisf ed in the mind of the engineer as to the security of the 

 fastening of the iron rod piles by merely jumping them from 15 to IS inches 

 info the rock ; they have, however, proved to be perfectly firm during heavy 

 floods, when the whole dam has been submerged, and the velocity of the 

 current which was nishing over it was not less than five miles per hour. 



This paper was accompanied by two drawings, showing the general arrange- 

 ment of the work, as well as the details of the construction of the coffre 

 dam. 



March 2. — The Presidext in the Chair. 



The following were balloted for and elected : Peter Hogg, Henry Oliver 

 Robinson, Thomas Oldham, Edward Jones Biven, and Robert Ransome, as 

 .Associates. 



