1842.] 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



267 



through the pumps, and partly by imperfect application of the water to the 

 wheel. 



II. Taylors North TJ'/ieel, 50 feet diameter, 6j feet broad ; was supplied 

 with 5199 gallons of water per niinute= r8""5 h.p. expended. It made 5 

 revobitions per minute, and worlied 6 pumps with a stroke of 6 feet ; weight 

 of the columns of water in those pumps 44,689 lbs., which was raised 30 ft. 

 per niinute = 40'63 h.p. reahzed ; being ol-6 per cent, of the power e.\- 

 pended. 



III. Taylor's South JJ'/ieel, 40 feet diam. 4 J feet broad ; supplied with 

 416"-4 gallons = 30-5 h.p. expended. It worked 2 pumps. feet stroke, 

 5 strokes per minute ; weight of columns 30-270 lb. = 27'53 h.p. realized ; 

 being 54'3 per cent. 



IV. Brentoa's /(Viee/, 32 feet diam. 7j feet broad; supplied with 8897'4 

 gallons = S6-3 h.p. expended. It worked 5 pumps, 6 feet stroke, 4} strukes 

 per minute; weight of column 30-092 lb. = 24-03 h.p. realized; being only 

 28-5 per cent, of the power expended, which is to l)e accounted for by the 

 additional friction of a great length of horizontal rods by which this wheel 

 works its pumps. 



OvEasHOT W.iTER Wheels AT Whe.^l Betsy JIi.nes, in July, 1811. 



I. Job's Wtieel, 42 feet diam., supplied with 2890 gallons of water per 

 minute = 36-78 h.p. expended. It made 4 revolutions per minute. Weiglit 

 of the columns of water in the pumps 28-314 Ih. feet stroke = 20-6 h.p. 

 realized ; being 36 per cent. 



II. Williams's W'Aec?, 40 feet diam. ; 3027 gallons per minute = 36-6S h.p. 

 expended. It made 4.^ revolutions. \Veight of columns 26-434 lb. ; "i feet 

 stroke = 26'43 h.p. realized; being 721 per cent. 



III. Buller's Wheel, 40 feet diam., 1912 gaIIon3 = 23-17 h.p. expended. 

 It made 3 revolutions. Weight of columns 22-901 lb. 7i feet stroke = 

 15'61 H.p. realized ; being 67-4 per cent. 



IV. Carpenter's Wtieel, 44 feet diam., 1983 gallons = 26-46 h.p. expended. 

 It made 4^ revolutions. Weight of columns 18-0C2 1b., 6 feet strokes 

 15'26 H.p. realized ; being 57'6 per cent. 



Conclusion. — If Brentoa's Wheel at Wheal Friendship is rejected, as an 

 extreme case, the average performance of the other three wheels at Wheal 

 Friendship will be 5S-3 per cent. ; and of the four wheels at Wheal Betsy 

 63-3 per cent. Or the average performance of all the seven wheels will be 

 61-2 per cent. 



Wheal r Old Sump 69-4 ] 



rriendshp. ^aylor^ North .... 51-6 I 58-5 per cent. 



' L Taylor 3 South .... 54-o J 



{Job's 50-0 "] 



Williams's 72-1 ^, „ 



Buller's 67-4 \ ^^'^ P''" •^«"'- 



Carpenter's 57-6 J 



Mr. Jordan described the turbine to consist of three principal parts : — 



1st. A cylinder with a base upon which are fixed the guide curves, direct- 

 Big the water at a certain angle upon the buckets of tlie moving ring. 



2nd. A sluice regulating the flow of water from the bottom of the cylinder 

 upon the buckets, and 



3rd. The external or revolving ring with its buckets, and its upright shaft 

 whence the motion is communicated to the machinery to be driven. 



The buckets are confined between two annular plates, tlie lower one being 

 attached to the vertical shaft, in the bottom of which is fitted a hardened 

 steel thimble, into which a pivot of " glass-hard steel " works ; tliis inversion 

 of the ordinary arrangement of the pivot, is to prevent any particles of sajid 

 or other substances from getting upon the point, and producing friction. Oil 

 is introduced to this pivot by a tube connected with a small pump, worked 

 by the machinery at the requisite speed to keep it lubricated. 



The form of the buckets is a mathematical curve, and on the pertection 

 with which this is traced, will depend tlie efficiency of tlie turbine. 



These parts are enclosed within a cylinder, so arranged that it shall serve 

 as the reservoir, whence the water is admitted upon tlio moving parts by the 

 sluice, which must be well fitted to prevent a loss of water, and is uniformly 

 raised or lowered by gearing placed on the top of the cylinder. When the 

 height of the fall is considerable, the cylinder is closely covered, and the 

 moving shaft passes through a stuffing bo.x in the centre, but with low falls 

 the cylinder is open at the top. 



A great advantage in the machine is, that the castings and iron work com- 

 posing it, are (with the exception of the buckets) very simple, they require 

 little adjustment, and only a few parts are turned or bored, so that tlie con- 

 struction ought to be economical. 



Mr. Rennie had endeavoured to introduce the turbine into notice some 

 years ago, and the nature of the curves had been examined in an article in 

 Herapath's Magazine. Professor Gordon's statement correspondeil very 

 nearly with what he had heard from MM. Foumeyron, Arago and .Morin, and 

 subsequently seen of these machines when in France. He had vi.■^ited a tur- 

 bine erected by a -Mr. Isterwood at a flour-mill at St. Maur, near Paris ; the 

 machine drove ten pairs of millstones 3 feet 4 inches in diameter, at tlie rate 

 of 200 revolutions per minute, equalling 40 h.p. ; subsequently three addi- 

 tional turbines were erected for the purpose of driving ten pairs of stones 

 each, or in all forty pairs of stones by four machines ; each turbine hail a 

 diameter of 3 ft. 2 in. and a depth of bucket of 8 inches, with a fall of water 

 of about 6 ft. : when entirely submerged to the depth of 4 feet, tlie turbine 



continued to make (as in low water) 50 revolutions per minute. Subse- 

 quently, in September 1840, he visited the flour mills of M. D'-A.rblay at 

 Corbeil. These mills are four in number arranged in a quadrangular form ; 

 each mill contains ten pairs of millstones, which were originally driven by 

 four well-proportioned cast iron wheels of about 18 ft. diameter ; two out of 

 the four wheels were still at work, but the other two had been replaced by 

 two turbines similar in dimensions to those at St. Maur. One of them was 

 working ten pairs of stones. The motion was communicated to a horizontal 

 shaft by means of bevil wheels, one fixed on the upper extremity of the up- 

 right spindle of the turbine, the other of smaller diameter fixed ou the end 

 of the horizontal shaft, on which also were fixed the riggers for driving, by 

 means of straps, smaller riggers fixed on the millstone spindles. The work 

 was very regularly done, and the proprietors expressed great satisfaction. 

 The second turbine was then erecting, and the third and fourth water-wheels 

 were to be replaced by similar machines. No fault was attributed to the 

 original wheels, but their efl'ect was not equal to that of the turbines. The 

 maker (.Mr. Isterwood) stated that he had made these machines entirely 

 under the direction of M. Fourneyron, who alone knew how to trace the 

 directing and emissive curves, and that unless they were properly described, 

 the effect would be greatly reduced. He at the same time stated as his 

 opinion, that there was no economy in the construction of the turbine over 

 the common water-wheel, as the former is more complicated and costly. 

 M. Fourneyron seemed to doubt whether any other machinist than himself 

 could construct a turbine properly ; the principal difficulty being in tracing 

 the curves, which had bean the study of his life ; he quoted several instances 

 of failure when strangers had attempted their construction. M. .Vrago and 

 M. Poneelet were of the same opinion ; the former stated that the effect of 

 the curves was contrarj- to theory. M. Morin expressed his confidence in 

 the accuracy of the experiment made with the fr'ene or friction brake of 

 Prony applied to the axes of the turbines. 



Mr. Rennie had seen a cast iron water-wheel with close buckets veiy 

 nicely balanced, 24 ft. diameter and 3 ft. 6 in. wide, made under the direction 

 of his father, realize 80 per cent, of eifective power, and Professor Gordon ia 

 the paper spoke of 82 per cent, for an overshot water-wheel. He did not 

 however by these observations mean to disparage the turbine, with which 

 the mechanical world generally was not sufficiently acquainted. 



r>lr. Taylor thought that Mr. Rennie had overlooked the two prominent 

 advantages of the turbine, in comparing it with other methods of employing 

 water power. 



1st. That of its being equally adapted for very low or for very high falls; 

 in falls under 10 feet the breast-wheel afl^orded but an imperfect mode of 

 using the power, as the actual efficiency fell far below what ought to be ob- 

 tained by a more perfect machine ; and in falls above 50 or 60 feet, if over- 

 shot wheels were used, a number of them must be constructed with the dis- 

 advantnge of increased expense and probable inconvenience in their appli- 

 cation. Instances had been adduced of turbines working with a fall as low 

 as 2 feet and as high as 343 feet ; the efficiency of the former being stated 

 at 64 per cent, and of the latter from 80 to 83 per cent. 



2nd. That they are not affected by back or tail water like almost all other 

 hydraulic machines; it having been shown, by direct experiment, that when 

 working at considerable depths under water, the relative proportion of use- 

 ful effect produced, to the total mechanical effect expended, is not thereby 

 notably diminished. This in his opinion was one of the most important ad- 

 vantages of tlie turbine. 



For high falls, the water-pressure engine and Barker's mill, as improved by 

 Whitelaw and Stirratt, rivalled the turbine ; and for low falls there were 

 many machines which were very effective ; for instance the balance-engine, 

 and the old " flap-jack," with a reservoir of water at one end of a beam and 

 a pump at the other; he had seen such a machine working with a ten-foot 

 stroke, pnmping from a depth of 200 fathoms ; but for falls subject to great 

 fluctuation, none of these machines appeared to equal the accounts given of 

 the turbine. 



Mr. Farey had not collected from the paper, or the discussion, how the 

 quantity of water passing through the turbine had been measured. The 

 power exerted appeared to have been tried by a break applied directly to the 

 axis of the turbine, whereas ordinary water-wheels are usually tried by the 

 work which they actually do perform, and that by the intervention of ma- 

 chinery which causes a considerable loss of power by friction. In order to 

 make a fair comparison, the two kinds of machines should have been 

 experimented upon exactly in the same manner, which did not appear to 

 have been done. 



When Mr. John Taylor stated, that the effect of the best of the large 

 water-wheels used for pumping water out of the mines under his manage- 

 ment, had been calculated to be 69 per cent, of the power expended ; it 

 would be found that the effect produced had been computed by the weight 

 of the columns of water in the pumps, multipUed by the height through 

 which such weight was raised ; such being the usual mode of reckoning. But 

 it is obvious, that much more power was exerted by the water-wheel than 

 would thereby be brouglit to account in the 09 per cent., owing to the fric- 

 tion of the pit-work and pumps by which the water was raised. The turbines 

 appear to have been tried in a way which would not incur much of that loss, 

 but which would bring to account in the per-centage nearly all the power 

 which, in practical operations, must be lost by the friction of the machinery 

 with which a water-wheel or a turbine must of necessity be connected, in 

 order to perform sucli operations. 



