1840.] 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



421 



without bliock, and quits it again Tivitliont velocity. A notion of its eonstrnc- 

 tion may readily l)e formed, by supposing an ordinary water-wlieel laid on 

 its side, the water being made to enter from the interior of the wheel by the 

 imier circumference of the crown, flowing along the buckets, and escaping at 

 the outer circumference. Then centrifugal force becomes a substitute for the 

 of gravity. A drawing was here exhibited of a Turbine of about 5 horse force 

 power, the fall being 3 feet, and the expenditure of water 20 cubic feet per 

 second. It was explained that the Turbine consists essentially of — 1. A re- 

 servoir, the bottom of which is divided into radial compartments by curved 

 plates, serving to guide the water to take a particular direction of efflux. 2. 

 A circular sluice, capable of nicety of adjustment. 3. The wheel with curved 

 buckets, on to which, when the sluice was raised, tlie water entered at every 

 point of the inner circiunference, and flowing along the buckets, escaped at 

 every i>oint of the outer circumference. This latter is a cliaracteristic feature 

 in tlin Turbines of Fourneyron. Reference was made to the principal Tur- 

 bines erected in France and Germany, — particularly to that at Inval, near 

 Gisors. and tliose at Miillbach .and Jloussay, as illustrative of their use for 

 falls varying from 9 inches to 10 feet. And, again, to those at St. Blasier, 

 in the Black Forest, as instances of high falls, — the one lieing 70v feet, the 

 other 345 feet ; the one expending 5 cubic feet per second, the other 1 cubic 

 foot per second; the one being 56 horse power, the other very nearly 60 

 horse power ; the one giving an eiHciency of upwards of TO, the other of up- 

 wards of 80 per cent, of the theoretical efl^'ect. A drawing of the latter was 

 exhibited — full size. It is 14-j inches diameter. Its extreme dejith or breast 

 is -225 inch, or less than I. It makes 2,200 to 2,300 revolutions jier minute. 

 It serves a factory, in which are 8,000 water spindles, 34 fine and 36 coarse 

 carding-engiues, 2 cleansers, and other accessories. The conclusions drawn 

 by Morier from his experiments on these wheels with the Break dynamome- 

 ter, or friction strap, are these: — 1. That Turbines are with equal advantage 

 a])plicable for high and for low falls. 2. That their net useful effect equals 

 70 to 78 per cent, of the theoretical effect of the power. 3. That they may 

 work at speeds varying from 



3-3 V 5-6 V 



Where »i = number of revolutions; V = velocity due to fall; R = extreme 

 radius. The useful effect still not dift'ering notably from the maximum. 4. 

 That they work at ver)' considerable depths under water, the relation of use- 

 ful to theoretical effect not being thereby much diminished. 



Mr. Smith (Deanstown) said, there was much in the principle for very high 

 and very low falls, and for varying falls. The principle had Ijeen long applied 

 in Perthshire, but in that part of the country a great velocity is obtained at a 

 great expenditure of power. — Prof. Gordon stated, that for all falls above 50 

 and below 10 feet, the Turbine is to be preferred.^Mr. Fairbairn : The com- 

 mon water-wheel at Gisors, in France, was made by himself and comparative 

 trials were made witli it against tlie Turbine. Mr. Fairbairn was quite satis- 

 fied, by Arago's experiments, and otherwise, that the Turbine is a very im- 

 portant machine, and gives a result of 70 to 75 per cent, of tlie theoretical 

 eflfect. — Mr. Smith proposed, that as he had peculiar facilities for experiment- 

 ing on the subject, he, along with Prof. Gordon and Mr. Fairbairn, should 

 investigate the comparative merits of the Tm-bine and other water-wheels 

 before tlie next meeting of the Association. 



" On prodncing True Planes or Surfaces on Metals." By Mr. Jos. Whit- 

 worth. 



Surface plates were exhibited, intended to illustrate the proper mode of 

 preparing surfaces where great accuracy is required. If one lie put upon the 

 other, it will float, until by its weight it has excluded some of the air, wheu 

 they will adhere together with considerable force. These surfaces were got 

 up without grinding. The only operations performed spon them were those 

 of planing, filing, and scraping. Practically, the excellence of a surface con- 

 sists in the number and equal distriliution of the bearing points ; the more 

 numerous these are, and the nearer together, the more perfect is tlieir action. 

 But, if a ground surface be carefully examined, the bearing points wUl be 

 generally found lying together in in'egular masses, vrith extensive cavities in- 

 tervening. The cause of this irregularity is evident in the unmanageable na- 

 ture of the process. The action of the grinding powder is under no control. 

 There are no means for securing its equal diflfusion, or for modifying its ap- 

 plication with reference to the particular condition of different parts of the 

 surface ; while the practical result is, that the mechanic neglects the proper 

 use of the file, knowing that grinding will follow, to efface all evidence either 

 of care or neglect. In various departments of the arts and manufactures, the 

 want of improvement in this respect is already felt. The valves of steam 

 engines, for example, the tallies of printing presses, stereotype plates, slides 

 of all kinds, require a degree of truth much superior to that they now possess, 

 for want of which there is great waste constantly accruing in time, in steam 

 power, in wear and tear, and, above all, in skill misapplied. The improve- 

 ments so much to be desired will follow upon the discontinuence of grinding, 

 The surface plate and the scraping tool will then come into vogue, and a new 

 field will be opened to the skill of the mechanic. Supposing him to be pro- 

 vided with a true surface plate, he will find no difficulty, after a little practice, 

 in bringing up his work to the required nicety. For this purpose he will find 

 it advantageous to employ a scraping tool made from a three-sided file, and 

 carefully sharpened on a Turkey stone, the use of which must be frequently 

 repeated. X light colouring matter, such as red chalk and oil, being spread 

 over the surface plate, and the work in hand applied thereto, friction will 



cause the prominent places to be marked, which will instruct the experienced 

 mechanic where and liow to operate to the greatest advantage. 



Mr. Scott Russell presented the Report of the Committee On the Form of 

 Vessels : the members of this Committee were Sir John Robison, Mr. Smith, 

 (Jordan Hill), and liimself. 



Since their appointment by the Association, the Committee had been con- 

 stantly engaged in carrying out the various investigations committed to their 

 charge ; and it had been their earnest desire to discharge their duties in such 

 a manner as conclusively to settle the many important practical questions in 

 naval arcliitecture whicli were matters of uncertainty and dispute, especially 

 in reference to steam navigation. The importance of precise knowledge in 

 constructing a mercantile navy.shijis of war, and steam vessels, was reckoned 

 so great, that in almost all civilized kingdoms experiments had been under- 

 taken at the national expense, and Italy, Spain, Sweden, and France had ob- 

 tained by those means a very superior knowledge of the principles of the con- 

 struction of ships. In this country the labours of individuals had supplied 

 the only experiments of this nature ; and it was matter of regret, that these 

 were not of such a description as to furnish the ship-builder with any certain 

 foundation for rules of art. The new demand upon the invention of the naval 

 architect by the introduction of steam power, had also contributed much to 

 augment the disparity which already subsisted between the data of experi- 

 mental hydrodynamics and the demands of the practical builder of ships. It 

 had also been thought not improbable, that certain singular phenomena in 

 hydrodynamics, recently discovered, might considerably modify the views 

 hitherto entertained of the nature of fluid resistance ; and the Association 

 had, therefore, resolved on the appointment of this Committee, for the pur- 

 pose of giving this subject a thorough and searching examination. The first 

 subject of concern with the Committee, was the mechanism by whicli to con- 

 duct experiments on a scale sufticiently large to render the results of juactical 

 value, and at the same time sufficiently manageable to free the experiments, 

 as far as possible, from elements foreign to the immediate subject of examina- 

 tion. It was desirable to obtain, for experiment, a force capable of moving 

 the vessels subjected to experiment, through the water with an uniform force 

 and velocity capable of being continued for a considerable interval of time 

 over a considerable length of space. All the forms of apparatus hitherto 

 adopted for the purpose of experiment, were examined with the view of 

 adopting the best. None of them appeared fully to answer the end in view, 

 and it became necessary to invent another and better apparatus for giring 

 motion to the vessels. This had been found ; a simple contrivance of Mr. 

 Russell's had beeii adopted, by which a force, perfectly uniform, could lie ap- 

 plied witliout inconvenience throughout any given space, free from the usual 

 errors of friction, rigidity, &e., whicli had become interwoven with the results 

 of former experiments. This apparatus he regarded as an engine of experi- 

 ment so important to the future acquisition of knowledge of the resistance of 

 fluids, that he was desirous to communicate it to the distinguished men around 

 liim taking an interest in the sidiject, in order that if it met their approba- 

 tion, they might avail themselves of it in future investigation. He then pro- 

 ceeded to give a description, with illustrative drawings, of an apparatus by 

 which experiments were made of from a small scale up to 100 feet in length, 

 over a sheet of water from 100 feet to half a mile or a mile in length. For 

 each scale of experiment, strings, cords, and ropes of various thickness were 

 employed ; and for the most delicate experiments, a slender Indian fibre, 

 brought home by Sir John Robison, had lieen found most useful. Two 

 chroiiometers by Robert, of Paris, also brought over by Sir John Robison, 

 were employed with great advantage, as observations were obtained which 

 could be depended on within two-tenth parts of a second. The next point 

 to be determined was. tlie general metliod of conducting the experimental 

 inquiry, so as to elicit the most valuable truths, and those most apposite to 

 practical art. For this purpose the most eminent ship-builders were consult- 

 ed, as to the points upon wliicli they most wanted information, and were re- 

 quested to point out what were the forms of vessel which they would wish to 

 have tried. More than 100 models of vessels of various sizes, from 30 inches 

 to 25 feet in length, had been constructed. These were drawn tlirough the 

 water with various velocities, and at difl'erent degrees of immersion, so as to 

 determine the resistance of all the various forms that might be adopted in 

 practice, and enable the builder to adopt the form best suited to his purpose. 

 A large pile of papers, laid on the talile, contained the results of the experi- 

 ments, which were still continued. Of these experiments, different series 

 were conducted with very various objects. One class regarded the transverse 

 sections of sliips ; another the water-lines of the bow ; another the water- 

 lines of the stern; another the form of ribbaud-line and of buftock-hne; 

 another class, the place of greatest breadth, and so on. From these experi- 

 ments it resulted that vessels might be made fidler than usual at some points 

 and finer in others, with great advantage, A peculiar class of lines, called by 

 Mr. Russell " wave lines," appeared best adapted for high velocities both in 

 smooth water and at sea. It also appeared, that the manner in which the 

 particles were displaced by a moving body, and replaced themselves after its 

 passage, was very different from what was generally supposed. There also 

 appeared to be three different conditions of fluid motion and resistance, ac- 

 companied with distinct characteristic phenomena : motion slower than that 

 of the wave — motion on the wave — motion on wings of water. The last oc- 

 curred only at vei7 high velocities, and when two high and beautiful films of 

 water spread themselves in the air, and carried the boat as on gossamer wings 

 along the snrface of the water. Mr. Russell concluded the report, by stating, 

 that the experiments would soon be published, and submitted to the examina- 



