64 



THK PRINCIPAL DSKS OF WOOD. 



The best woods for naves are babul, sissu, sal, black-wood, teak, 

 various Albizzias, and satin-wood. 



The wood of spokes should be all heart-wood, very strong and 

 hard, elastic yet rigid enough, not liable to warp or split, perfectly 

 straif^ht-grained, and without knots and any trace of unsoundne-ss. 

 It should be remembered that the whole weight of the carriage or 

 wagon is borne successively by an individual spoke in each wheel, 

 so that a single bad spoke spoils an otherwise perfect wheel. To 

 prevent the tires from becoming- loose in hot, dry weather, the 

 length of the spokes should not be liable to vary much with alter- 

 nations of atmospheric humidity. The most suitable woods for 

 spokes are sissu, sundri, teak, and babul. 



The felloes should be made of some wood that is able to resist 

 crushing, is hard, elastic and strong, does not warp or split and 

 is not liable to excessive expansion or contraction with varying 

 quantities of imbibed water. Durability is also an essential 

 quality, and hence no sapwood should be allowed to remain. To 

 preserve all the strength and elasticity of the wood, the fibres 

 should be cut across as little as possible, and hence the advisability 

 of using naturally curved timber. When such pieces are not 

 obtainable, then the felloes should be hewn out of split sections, as 

 represented in Fig. 12, so that the concentric rings may all lie 



Mode of cutting out fellies. 



