TIMBER EMPLOYED IN COACH-BUILDING. 369 



fibrous than an elastic wood, and is well calculated to 

 bear the concussions to which the supporting frame- 

 work of a coach is exposed ; it is best fitted for use 

 when arrived at maturity, but before it has attained 

 its extreme size. It is sometimes white at the heart, 

 sometimes red ; the former is best suited for the pur- 

 pose in view. It is sometimes so wrinkled and twisted 

 in the grain as to render it almost impossible to plane 

 it out smooth; but it is then in its toughest state, and it 

 acquires by boiling or steaming a plastic property, 

 which enables it to be bent to a form suited to carriage 

 timbers. These various qualities, together with the 

 absence of any tendency to warp or twist, render ash 

 better fitted than any other kind of timber for the 

 skeleton framework of a coach. 



Elm is used sometimes for strong planking ; of 

 the two kinds hedge-row elm is more employed than 

 wych elm. The grain of this wood is curly and wavy, 

 difficult to work, brittle, and apt to split ; but, when 

 once brought into workable form, elm possesses great 

 strength, especially for the naves of wheels. Oak is 

 not employed to any considerable extent in coach- 

 building, yet it forms the spokes of wheels. The 

 nave, a cylindrical block of wood into which the 

 spokes are fitted, is sometimes of elm and forms the 

 centre of the wheel ; it is pierced longitudinally with 

 a hole to receive the axle. The spokes are, of course, 

 the radiating arms framed into the nave at equal 

 distances, and the felloes are circular segments framed 

 or fitted on to the outer extremities of the spokes and 

 forming collectively the periphery or rim of the wheel. 

 The first thing to be considered is the wheel. Each 

 felloe has at least two spokes ; felloes are sometimes 

 made in one piece of wood which is bent into a 



2 B 



