W H E 



W H E 



\icck. This button is fitted and received into a fockct, in 

 which it can freely turn round, but cannot draw out end- 

 ways. It is made in a piece of metal, which is cylindrical 

 on the outfide, and of the fame fize as the axle. It is made in 

 two halves, which feparate longitudinally to introduce or 

 take out the button at the end of the axle ; but when the 

 two halves are put together, the focket-piece forms as it 

 were a continuation of the axle. When the axle is put 

 into the box with this focket-piece at the end of it, the two 

 halves of the focket will be confined together, fo that they 

 cannot feparate ; and to prevent them from drawing out of 

 the box, a fcrew-bolt is put through the box, arid pafles 

 through both halves of the focket : this holds the focket 

 and the axle in their places. 



Mr. Ackermann has recently obtained a patent (1818) 

 for a valuable improvement in the application of the fore- 

 wheels to four-wheeled carriages. In our article Coach- 

 Maiing, vol. viii. we have defcribed thofe methods which 

 were then known of applying the fore-wheels, fo as to 

 make a four-wheel carriage turn with fafety, and in a fmall 

 fpace. See alfo Perch. 



Mr. Ackermann's improvement effefts this in the moft 

 perfeft manner. Each of the fore axle-trees is connefted 

 with the carriage by means of a vertical axle, formed in the 

 fame piece with the horizontal axle, and upon which the 

 wheel turns, the two axles being fituated at right angles to 

 each other. Thefe vertical axles are fitted mto focketf, 

 formed at the two extremities of a crofs beam of the frame 

 of the carriage, which is called the fore-ipring tranfom. 

 Upon thefe axles, as centres of motion, the axle-arms and 

 wheels can be turned about horizontally, in order to place 

 them obliquely to the direftion of the hinder-wheels when 

 the carriage is required to turn ; but each axle turns upon 

 a feparate centre of motion, and thefe centres are very near 

 to their refpeftive wheels, being at the extremities of the 

 crofs-beam or tranfom ; hence the fore-wheels do not 

 change their place upon the ground when they are placed 

 obliquely. i 



In a common carriage, the axles of the two fore-wheels are 

 both fixed to one piece of timber, called the axle-bed, 

 which is placed beneath the fore- tranfom, and united to it 

 by a vertical pin called the perch-bolt, paffing through the 

 middle of the axle-bed. On this pin, as a centre, the axle- 

 bed is turned round. When the wheels are to be placed 

 obliquely, it is evident, that, in fo turning upon a fingle 

 centre, one wheel muft advance forwards, and the other muft 

 retreat backwards, fo as to diminifh the bearing of the 

 carriage-wheels on the ground in a lateral direftion, and at 

 the fame time the horfes are pulling in that direction which 

 tends to overturn the carriage. Another inconvenience is, 

 that one of the wheels will touch the perch of the carriage, 

 if placed very oblique. 



In the new improvement, two feparate centres of motion 

 being ufed, and thefe being removed from each other as far 

 as poflible, many defirable properties are attained. 



To give the oblique direAion to the wheels, each vertical 

 axle has a lever proceeding backwards from it ; and thefe 

 two levers are united together by a conneding-bar, which 

 obliges both axles to move at the fame time with a fympa- 

 tbetic aftion. The pole of the carriage is united to the 

 piece, called the futchel, in the ufual manner ; and the 

 futchel is united to the fpring- tranfom by a perch-bolt, in 

 the ufual pofition ; alfo the hinder end' of the futchel is 

 jointed to the middle of the conneAing-bar, between the 

 two levers of the vertical axles. The conneding-bar like- 

 wife anfwers the purpofe of a fway-bar. 



When the horfes move to one fide, the pole and futchel 

 9 



turn upon the perch-bolt, as a lever upon a centre of motion ; 

 and the extreme end of the futchel afts upon both vertical 

 axles at once by means of the conneAing-bar, fo as to place 

 both of the fore-wheels in an oblique direAion. This is 

 the invention of M. Lankenfperger of Munich. 



Wheel, Arijlotle's. See Rota Ariflotelica. 



Wheel, Bloivlng, a machine contrived by Dr. Defagu- 

 liers for drawing out the foul air of any place, or for forcing 

 in frefh, or doing both fucceffively, without opening doors 

 or windows. See Phil. Tranf. N° 437. 



The intention of this machine is the fame as that of 

 Dr. Hales's ventilator, but not fo effeAual, nor fo con- 

 venient. See Defagul. Courfe of Exper. Philof. vol. ii. 

 p. 563. 568. 



This wheel is alfo called a centrifugal ivheel, becaufe it 

 drives the air with a centrifugal force. 



Wheels, Bufhes or Boxes of, the infide metal linings of 

 the naves. See Wheel. 



Wheel, Cutting Roller, in Agriculture, a tool of the 

 cutting and reducing fort, ufed for the purpofe of working 

 over crops in fome cafes. In Oxfordlhire a cutting roller 

 of this fort has been invented, which is compofed of twelve 

 wheels, two inches and a half in thicknefs ; and between 

 each of them is a fpace of two inches and a half. They are 

 three feet in diameter. It is a load in working fo as to be 

 fufBcient exertion for a ftrong team to draw it : it is pafled 

 over wheat after it has been fown, or after it is come up ; 

 and if dry, crofs and crofs. It has alfo been ufed in the 

 fpring upon wheat ; it leaves the furface rough in a fort of 

 diamond forms, which is found very beneficial in fome of 

 the wheat-lands of that diftriA. It is alfo capable of being 

 ufed in breaking down the furface of ftiff tillage -land in 

 many other cafes and circumftances. 



Wheel, Draining, a wheel conftruAed for the purpofe 

 of cutting or making drains. Wheels differently formed 

 are ufed for this fort of work. In Eflex they employ 

 workmen who make ufe of a caft-iron wheel which weighs 

 about four hundred weight, and which is four feet in diame- 

 ter ; the cutting edge or extreme circumference of the wheel 

 being half an inch in thicknefs, which incrcafes in this way 

 as it approaches towards the nave or centre ; and will, at 

 fifteen inches deep, fcour out or cut a drain half an inch 

 wide at the bottom, and four inches wide at the top. The 

 wheel is fo placed in a frame, that it may be loaded at plea- 

 fure, and be made to pafs to a greater or lefs depth, as the 

 nature of the land may be. 



The writer of the Middlefex Report on Agriculture 

 advifes the ufe of a common fix-inch cart-wheel, on the 

 felly of which, all round, a fort of ridge-formed addition of 

 wood is to be fixed, and a rim of iron of a triangular fhape 

 fattened to the wood. A wheel of this kind put on the 

 axle of a cart, in the ufual way, will, of courfe, reft on the 

 edge of the rim of iron ; and which, on driving the horfe 

 forward, will make a fmall indent or depreffion in the 

 ground merely by the revolution of it ; but in order ..to 

 make it prefs down to the depth of fix or eight inches, that 

 fide of the cart (hould be loaded with ilones, iron baUaft, 

 or any other heavy material that may happen to be at hand, 

 until the whole of the parts, if neceifary, fink into the foil. 

 It would however be as well, or better, it is faid, if the rim 

 parts added to the wheel were in one piece of calf -iron ; as 

 the iiicreafed weight of it would enable it to cut or fink 

 without the aid ot ballaft, or with lefs than ufual. The 

 cart (hould then be drawn along in fuch a manner, that the 

 cutting or depreffing wheel may revolve where the drains are 

 intended to be made. In land that is in ridges and furrows, 

 it will fometimes be neceffary to draw the wheel along every 



furrow. 



