WATER. 



diftinft cell to receive each arm, and they are faftened into 

 the cells by wedges and fcrew-bolts, bui a flat flanch with 

 tlie intervals filled up by blocks is more fimple and fecure. 

 Modern wheels are very frequently made with caft-iron arms, 

 which in this cafe are attached to the axis by a fimilar 

 centre-piece. 



The circular rims of water-wheels are commonly made of 

 wood, put together in two or three thickneffes, the joinings 

 of one ring not coinciding with thofe of the other, and 8 or 

 lo fegments in each thicknefs, according to the fize of the 

 wheel ; the thicknefles are united together by rivets. The 

 arms are attached to the ring by notching them in, and fe- 

 curing them by bolts. Caft-iron rings are now generally ufed, 

 and with great advantage, becaufe the neceffary mortifes 

 can be made in iron, without weakening the ring ; but the 

 ftrength of a wooden ring is greatly impaired by the mor- 

 tifes through it. 



The number of rings in a wheel depend upon its breadth; 

 when the wheel is four feet wide, two rings will fupport the 

 float-boards or buckets, but the rings fhould not be more 

 than five feet afunder, or the floats may bend and yield ; for 

 want of a fufGcient fupport each ring is framed with its fet 

 of arms, fo that every one derives its ftrength from the 

 axis. When a wheel is of great breadth, the whole will be 

 Tery much ilrengthened, by applying oblique braces, ex- 

 tending from the centre-pieces of the outfide rings to the 

 circumference of the middle ring, by firmly attaching thefe 

 oblique braces to the arms of all the rings which they inter- 

 cept ; they form trufs-franies which prevent the wheel and 

 the axis from bending by its weight : this is particularly 

 ufeful in wide overfhot wheels. 



In breaft and underfhot wheels the float -boards are nailed 

 to pieces of wood called ftarts, which are fixed into the mor- 

 tifes in the rings, and projeft outwards for that purpofe. 



In overfliot-wheels, the rings of the wheels are covered by 

 boards laid parallel to the axis, well jointed together, and 

 fpiked down to the rings like the boards of a floor to the 

 joifts. This boarding forms a clofe cyhnder, which is called 

 the fole of the wheel, and is the foundation for the buckets. 

 When the rings of the wheel are of iron, holes are left in 

 the cartings in the edge of the rings, at regular diftances 

 round the circumference, and thefe are filled up with plugs 

 of wood, into which the nails can be driven to fatten on the 

 boarding of the fole. The fole of the wheel is fometimes 

 made of iron plates rivetted together, and rivetted alfo to 

 the rings of the wheel. 



At the ends of the fole-boards, two circular rings of 

 wood or iron, called fhrouds, are fitted on perpendicularly 

 to the fole to form the ends of the buckets ; and it is ufual, 

 if the wheel is wide, to apply a fhrouding over each ring of 

 the wheel, and then the buckets are divided into lengths of 

 about four or five feet. In the flat furfaces of the ihroud- 

 ings, grooves are made for the reception of the ends of the 

 bucket-boards. It is ufual to make the firft board, which 

 is in the direftion of a radius, of wood, and the outfide one 

 is generally made of iron plate ; but fometimes the whole 

 are made of plate iron, and both parts of the buckets are 

 then bent up out of one piece, and the ends of the plate ; and 

 alfo that part of tlie edge which is to apply to the fole, is 

 turned fquare to lie flat againft the fole and the flirouding, 

 fo that rivets and nails may unite all together, and make 

 water-tight joints. 



When the (hrouding is of caft-iron, it is made to ferve 

 inftead of the rings of the wheel, becaufe it has fuf&cient 

 ftrength to ferve both purpofes : the arms of the wheel are 

 in this cafe applied flat againft the ring of flirouding, and 

 bolted to it. 



Vol. XXXVIII. 



The breaft-wheel,/^. 3. Plafell. Water-'wheels, at MeflVs. 

 Strutt's works, which we have already noticed, is deferving of 

 further notice from the manner of putting it together. The 

 rings of the wheel are made of caft-iron, and the float-boards 

 arc mcluded between the rings in the manner of an overftiot 

 wheel, but the arms are only of wrought iron, being made 

 of fmall round iron rods, which are very light, and have little 

 ftrength to refift bending ; but as they are all tied in from 

 the centre, the ring cannot deviate from its true circular 

 figure, and to fuftain the wheel fideways, oblique bars are 

 extended from the centre-pieces at each end of the axis, and 

 are united to the circular ring in the middle of its breadth, 

 which is 15 feet. We have feen two overfhot -wheels of 24 feet 

 diameter, and 9 feet broad, made in the fame way. It is 

 plain that in this conftrudlion the axis of the wheel can do 

 no office but to fupport the weight of the wheel ; for though 

 thefe arms are fufficiently ftrong for that purpofe, they can 

 have little ftrength by way of levers to tranfmit the force 

 of the circular motion of the rim of the wheel to the axis ; 

 but the power is tranfmitted in a better way than from the 

 axis, •viz. by a ring of cogs fcrewed to the circular rim of 

 the wheel, and working in a pinion which conveys the mo- 

 tion to the mill. There is another fimilar ring of cogs at 

 the other fide of the wheel, which works into a pinion fixed 

 on the fame fliaft, by this means nearly all the ftrain is taken 

 from the axis of the water-wheel ; for the pinion is placed 

 on the defcending fide of the wheel, fo that the weight of the 

 water adting on the float -boards is immediately tranfmitted to 

 the pinions by the ftrength of the rings of the wheel. 



This method of tranfmitting the power is alfo apphed to 

 other wheels than thofe which are made with flight arms 

 like the above ; the ring of cogs is fometimes placed in the 

 middle of the breadth of the wheel, and then afts upon one 

 pinion, but it is much bttter to place it at one fide or both 

 fides, if the wheel is very broad, becaufe the circle of the 

 teeth may then be made rather lefs than the diameter of 

 the rings of the wheel, and the fide of the ring being clofely 

 fitted to the ftone-work of the race, the water may be ex- 

 cluded from the cogs. 



It is obvious that of the various conftruftions of water- 

 wheels, that is the ftrongeft which communicates its motion 

 by means of a ring of cogs immediately attached to its rim, 

 where the power of the water is alfo applied, the leaft pof- 

 fible ftrain being thus thrown on its arms and axis. 



The only objeftion to this plan is, that as the teeth of 

 the cog-wheel are in moft cafes conftantly wet, which pre- 

 vents the greafe from adhering, the ufual mode of occa- 

 fionally greafing the cogs is of little or no ufe, and the dirt 

 in the water grinds away the teeth ; or, were the water even 

 free from dirt, there would be much unneceflary friftion and 

 wafte of power. 



Greafing Maehine for the Cog-Wheel of a Water- Wheel. — 

 Mr. Buchanan mentions two water-wheels of this kind, in 

 which the rings of the teeth were wearing very faft, and 

 knowing the trouble and expence of renewnig them, he was 

 folicitous to difcover fome means of rendering them more 

 durable. The only way which prefented itfelf was by fome 

 contrivance to keep them well greafed. 



This he did by a machine ftiewn v\ fg. 8. Plate!. Watcr- 

 -juheeh ; it is nothing more than a kind of pinion, with one 

 or more of its teeth made hollow to contain the- givaiy fub- 

 ftance, and the metal plate of which the hollow cog is com- 

 pofed is perforated with fmall hole?, for oxudating the 

 greafe through tliofe parts which come in contaft with the 

 teeth of the wheel. 



Fig. 8. is a feftion of the greafing macliine ; A B repre- 

 fents part of the ring of teeth on the circumference of the 



N > water- 



