isig.i 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



237 



that nfarly all the power was used. He admired the details of construction 

 of Mr. Fairhairn's wheels, particularly the arrangement for taking the lift on 

 the loaded sirie of the wheel, and thus making the axle only the means of 

 retaining the wheel in its place. 



Mr. Fairbairn stated, in answer to Captain Moorsom, that he considered 

 tlie form of the hucket did conlrihute materially to the regidarity of motion. 

 It was important to carry the water down as near to the vertical centre as 

 possihle, so as to get the hest effect from it, and yet to begin to part with it 

 as soon as that line was ])assed. That form was also found to till better, and 

 waste less water in times of drought, whilst it worked very easily, and with- 

 out injury from hack-water in times of flood. The ventilating wheels were 

 not so essential for very hi^h falls; they would be more expensive, and the 

 measure of all benefit being the cost, he could not consider them of much 

 advantage for high falls. 



Mr. Beardmoke thought that there was scarcely a situation in Cornwall 

 to which this kind of wheel was applicable, as all the falls were very high. 

 The wheels in that district were chiefly emj)loyed for working stampers, or 

 for pumping. In neither case was regularity of action at all necessary : for 

 pumping, an exertion of force was essential to raise the heavy plunger-rods, 

 and tlien the wheel might run at any velocity during the other portion of its 

 revolution ; and before the next stroke was made, power was accumulated, 

 by the extra filling of these particidar iiuckets,the others possibly not having 

 been more than half-filled : the njilUvright therefore gave plenty of bucket 

 room, and ventilation was alVorded at the extremities. 



where it was important to obtain the utmost regularity of movement. He 

 had heard it remarked, that the yarn spun by water-power obtained a higher 

 price in the market than that produced by steam-power. Mr. Russell had 

 tried some experiments on water-wheels, and found the radial breast-wheels 

 give very good results, with a fall of about 14 feet, and the sluice and 

 water-course so arranged as to bring the water on with as little velocity a! 

 possible, filling the buckets properly — which, however, could only be accom- 

 plished up to a certain speed without a system of ventilation. In high falls, 

 this became even more essential, and, in fact, indispensable. 



Mr. Fairbairn Mplained, that he had tried both methods of taking off 

 the power, and preferred taking it from one side only, as, in addition to the 

 other objections, when the gearing was fixed on both sides, the elasticity of 

 the wrought-iron tension arms tended to break the teeth of the pinions. It 

 could therefore only be done when the wheel was perfectly rigid. Mr. Strutt, 

 of Derby, and the late Mr. Hewes.of Manchester, bad made many important 

 improvements in v\ater-wheels, particularly those on the suspension principle, 

 which appeared now to be acknowledged as the most advantageous con- 

 struction. 



Mr. De Bergue said he had obtained nearly seventy-eight per cent, of 

 power from a breast-wheel, with a good fall, when the periphery was travel- 

 ling at a velocity of 6 feet per second. He had erected several of Poncelet's 

 wheels, and thought well of them ; indeed, for certain situations he thought 

 thev were preferable to any other form, although M. Poncelet had never yet 

 been able to obtain very superior results from wheels erected under his own 



Fig. C, — Water-wheel on Poncelet's system. 



Mr. WicKSTEED considered the wheels in Cornwall and those in Lancashire 

 were so differently employed, that no useful comparison could be drawn 

 between them. He thought, however, that no doubt could exist as to the 

 advantages of Mr. Fairhairn's improvements, where steadiness of action, and 

 the economical use of water, were required. He apprehended that some 

 difBculty might occur in times of flood ; but the form of the buckets was 

 calculated to meet, to some extent, even that objection. Great attention ap- 

 peared to be deservedly given to the angle formed by the bucket with the 

 periphery, and he conceived that it was a question of importance, particularly 

 in relation to the amount of strain upon the axis. Mr. Wicksteed had 

 tried some experiments upon large-sized water-wheels, built both on Smea- 

 ton's and Rennie's systems, but had not obtained from them more than 

 fifty-six per cent, of power: the velocity was generally about 6 feet per 

 second. 



Mr. Scott Russell had rarely seen better designed, or more ably executed 

 machines, than these ventilated water-wheels, and he thought the profession 

 was under obligation to Mr. Fairbairn for the improvement he had intro- 

 duced. He might instance, especially, one point of importance; this was, 

 the method of taking off the power, by inside gearing, from the loaded part 

 of tbe periphery, thus avoiding all risk of straining the wrought-iron tension 

 arms. Attempts had been made to improve upon the system, by taking off 

 the power from the two sides of the wheel ; but they had not been success- 

 ful, as the gearing on both sides did not work well together, and a tremulous 

 motion was communicated, which was very objectionable for spinning-mills, 



superintendence. Mr. De Bergue then exhibited a drawing (fig. 6), and ex- 

 plained the construction of a wheel, on this principle, to be erected at the 

 Loubregat, near Montserrat, in Catalonia; one of the same kind having been 

 already erected by him at Gerona, between Barcelona and Bellegarde. The 

 diameter was IG ft. 8 in., and the width was 30 feet, which, with a fall of 

 6 ft. 6 in., passed 120,000 cubic feet of water per minute, when the periphery 

 travelled at a velocity of 11 to 12 feet per second. An ordinary breast- 

 wheel would require to be 90 feet wide, to use advantageously that quantity 

 of water. It was found that the velocity of the periphery should be about 

 fifty-five per cent, of that of the water flawing through the sluice ; and upon 

 these data the power of the wheel would be about 180-horse power. The 

 buckets were of a curved form, and made of wrought-iron J of an inch 

 thick ; and it would be observed that there was a larger number of buckets 

 than usual, and that the water came upon them at a tangent, through an 

 orifice of such a form and dimensions as to allow the buckets to fill easily, 

 at the rapid speed at which the periphery passed before the sluice. This 

 great primary velocity was very important, as it caused a considerable saving 

 in the gearing of the mill. The main shaft was formed by a hollow cylinder 

 of cast-iron, 4ft. Gin. diameter, in short lengths, bolted together; and the 

 arms were of wrought-iron, made very light, and of the same form as those 

 of a paddle-wheel of a steamer, and placed very close together. The strain 

 was brought entirely upon the main shaft, and the weight of the wheel was 

 thus reduced to about 30 tons, which was very little for so powerful a 

 machine. The sluice was formed of cast-iron plates, with planed joints, 



