THE WEDGE. 93 



vests, that the wheat has actually been allowed to rot, 

 because it would not repay the cost of carriage." 

 Again, "When the Spanish government required a 

 supply of grain to be transferred from Old Castile to 

 Madrid, 30,000 horses and mules were necessary for 

 the transportation of four hundred and eighty tons of 

 wheat. Upon a broken-stone road of the best sort, one 

 hundredth of that number could easily have done the 

 work." He further adds, in speaking of the improve- 

 ments in roads made by Marshal Wade in the Scottish 

 Highlands, " His military road is said to have done 

 more for the civilization of the Highlands than the 

 preceding efforts of all the British monarchs. But the 

 later roads, under the more scientific direction of Tel- 

 ford, produced a change in the state of the people wliich 

 is probably unparalleled in the history of any country 

 for the same space of time. Large crops of wheat now 

 cover former wastes ; farmers' houses and herds of cat- 

 tle are now seen where was previously a desert ; estates 

 have increased seven-fold in value and annual returns ; 

 and the country has been advanced at least one hund- 

 red years." 



SECTION VII. 

 THE WEDGE. 



The wedge is a double inclined plane, the power 

 .being apphed at the back to urge it forward. It be- 

 comes more and more powerful as it is made more 

 acute ; but, on account of the enormous amount of 

 friction, its exact power can not be very accurately es- 

 timated. It is nearly always urged by successive 



