WATER. 



wheel can at all times take the utmoil fall of the water, even 

 when its height varies from three to four feet. A A is the 

 pentrough made of caft-iron ; the end of it is formed by a 

 grating of broad flat iron bars, which are inchned in the 

 proper pofition to direft the water through them into the 

 buckets of the wheel. The fpaces between the bars are (hut 

 up by a large (heet of leather, which is made fall to the bottom 

 of the iron trough at a, and is applied againft the bars ; and 

 the preflure of the water keeps it in clofe contaft with the 

 bars, fo as to prevent any leakage. This is the real (huttle, and 

 to open it fo as to give the required ftream of water to the 

 wheel, the upper edge of the leather is wrapped round a 

 fmaller roller b ; the pivots at the ends of this roller are re- 

 ceived in the lower ends of two racks, which are made to 

 Aide up and down by the aftion of two pinions fixed upon 

 a common axis which extends acrofs the trough ; this axis 

 being turned, raifes up or lowers down the roller, and the 

 leather (huttle winds upon it as it defcends, or unwinds from 

 it as it afcends, fo as to open more of the fpaces between the 

 bars, or clofe them as it is required. In order to make 

 the roller take up the leather, and always draw it tight, a 

 ftrap of leather is wound round the extreme ends of the 

 jj-oUers, beyond the part where the leather (huttle rolls upon 

 It. Thefe ftraps are carried above water and applied on 

 wheels, which wind them up with a very confiderable tenfion 

 by the aftion of a band and weight wrapped on the cir- 

 cumference of a wheel, which is on the end of the axis of 

 thofe wheels. 



The water runs over the upper fide of the roller, and flows 

 through the fpaces between the grating into the buckets of 

 the wheel ; the defcent of the water pafling through the 

 bars, and afterwards in falling before it ftrikes the bottom 

 of the bucket, is found fully fufficient to produce the ne- 

 cefTary vtlocity of the water, for a fall of four inches pro- 

 duces a velocity of more than four feet per fecond. 



We recommend this as the beft; method of applying the wa- 

 ter, as we fee in all other forms that a much greater portion of 

 the fall is given up in order to make the water flow into the 

 wheel ; not that any fuch depth as is commonly given is at 

 all necelfary, but the aperture in the trough mull be placed 

 fo low that the water will run through it in the very loweft 

 Hates of the water, otherwife the wheel mull Hop at fuch 

 times. 



On (he Manner ef framing Waler-nvheeh. — The weight of 

 every wheel mult be fupported by its axis, which therefore 

 demands the firll confideration. If the axis is to be of wood 

 it fhould be made of a tree of hard and durable wood, of a 

 length and fize proportioned to the lize and weight of the 

 wheel ; mto each end a gudgeon or centre fliould be fixed 

 for the wheel to turn upon. There are two methods of fixing 

 the gudgeon into a wooden axis ; one is, by forming the 

 gudgeoi; with acrofs, which is let into the end of the tree, 

 and faftened by fcrews, and the wood is comprefled round 

 the crofs by two or three iron hoops, fitted on the end of 

 the tree iud wedged ; this is explained in the article MlLL- 

 Work. The other method is, to make a Itrong iron box in a 

 piece w'th the gudgeon, into which box the end of the tree is 

 received and fecured by wedges. The box being of an ofta- 

 gon Ihape, and the wo d being cut to the fame figure, it 

 cannot flip round withni \\p box. 



Of late years it has btc i il'ual to make the great axis of 

 water-wheels of cail-iroii, which is a very good plan, pro- 

 vided the axis is made of fufficient dimenfions. This was 

 firll prailifed by Mr. Smeaton, but he was rather unfor- 

 tunate, as fevenJ of them broke after having been many 

 years in ufe : he then employed hollow lubes of call -iron of 

 large dimenfions and confiderable thicknefs of metal. Even 



now that the ftrength of call -iron is better underftood, it is 

 not uncommon for the axis of a water-wheel to break, par- 

 ticularly in cold and frofty weather, and for this reafon fome 

 millwrights ufe wrought iron, but the hollow tube is fo much 

 ftronger, as to be very fecure from accident. 



In an iron axis it is advifeable to make the bearings of the 

 axis clofe to the fides of the water-wheel, and leave the ends 

 of the axis projecting beyond the bearings, in order to attach 

 the cog-wheel, by which the power of the wheel is to be 

 communicated to other machinery. This diminifhes tl-.e 

 length of the axis between the bearings, and renders it much 

 ftronger ; wooden axes mutl have the gudgeons at the ex- 

 treme ends. 



The next point to be confidered is, the beft means of afEx- 

 ing the arms of the wheel firmly to the axis. If the arms 

 are of wood, and the axis alfo, the mod obvious plan is to 

 mortife the arms into the axis ; but this is the worll method 

 that can be adopted, becaufe the axis is much weakened, and 

 the water being admitted into the centre of the tree caufes it 

 foon to decay, nor can an arm be eafily replaced without 

 taking all the wheel to pieces. 



A better way is to ufe eight timbers for the arms, and put 

 them together fo as to interfeft each other at right angles, 

 (as is fliewn v^fig- "]• Plate I. ) leaving a fquare opening in the 

 centre for the reception of the axis, which is made up to a 

 fquare by adding pieces of wood to it, and the wheel is faf- 

 tened on by wedges. The only objeftion to tliis is, that 

 the arms are weakened by interfefting each other, and 

 they fupport the circular rim of the wheel in unequal feg- 

 ments. 



In Mr. Buchanan's water-wheel, which we have before 

 defcribed in Jigs. 4 and 5, Plate I. Water -ivheels, is a parti- 

 cular conftruftion of the arms formed by thin planks of wood. 

 He ftates that this plan is applicable to any kind of water- 

 wheel ; and fince 1 790, when he firfl conltrufted a wheel 

 with arms on that principle, a confiderable number of large 

 wheels have been erefted in Scotland on the fame plan. It 

 is evident that arms, fuch as are commonly fixed in mortifes 

 in the axis, are weakell in one direftion, and that commonly 

 in the direftion of the ftrain. To remedy this defeft the 

 feather-pieces F F are applied all round, having their broad- 

 elt ends towards the centre of the wheel, and being at right 

 angles to the breadth of the principal arms. In order to 

 unite them ftrongly to the principal arms, and conneft the 

 whole more firmly together, a ring of iron, R, is applied 

 on each fide ; blocks of wood being put in the vacant fpaces 

 between, and the keys or wedges, K K, bind the whole clofe 

 to the axis. 



The very beft method of uniting the arms to the axis is to 

 have a caft-iron centre-piece, or ftrong hoop, to fit on the 

 wooden axis with a broad projefting flanch round it, againft 

 the flat furface of which the arms of the wheel are applied, 

 and the intervals between them filled up by wooden blocks 

 or wedges ; the arms and blocks are firmly bound to the iron 

 flanch by iron rings applied to the arms on the oppofite fide 

 to the flanch, with fcrew bolts to go through the whole. 

 This fame plan is applicable to an iron axis, and will be more 

 clearly underftood by a reference to the article Mill, and 

 Plate XXXIV. Mechanics ; but it is there defcribed that the 

 broad circular flanch to fcrew the arms againft, is caft in the 

 fame piece with the axis. This was Mr. Smeaton's original 

 plan, but the flanch fhould be made in a feparate piece, and 

 faftened on .the axis v/ith wedges ; for' if caft in the fame 

 piece, the contradioa of the metal contained in the flanch 

 when cooling, renders the metal of the axis fpongy at the part 

 where it joins to the flanch, and caufes them to break at that 

 part. Sometimes the caft-iron centre -piece is made with a 



diftiuA ; 



