CHAP. VI. BLENKINSOP'S ENGINE. 85 



his patent, provided that the periphery of the driving- j 

 wheels should be made rough by the projection of bolts 

 or cross-grooves, so that the adhesion of the wheels to 

 the road might be secured. 1 



Following up the presumed necessity for a more 

 effectual adhesion between the wheels and the rails, 

 Mr. Blenkinsop of Leeds, in 1811, took out a patent for 

 a racked or tooth-rail laid along one side of the road, 

 into which the toothed-wheel of his locomotive workecj 

 as pinions work into a rack. The boiler of his engine 

 was supported by a carriage with four wheels without 

 teeth, and rested immediately upon the axles. These!, 

 wheels were entirely independent of the working parts 

 of the engine, and therefore merely supported its weight 

 upon the rails, the progress being effected by means of 

 the cogged-wheel working into the cogged-rail. The 

 engine had two cylinders instead of one, as in Trevi- 

 thick's engine. The invention of the double cylinder 

 was due to Matthew Murray, of Leeds, one of the best 

 mechanical engineers of his time ; Mr. Blenkinsop, who ' 

 was not himself a mechanic, having consulted him as to 

 all the practical arrangements of his locomotive. The 

 connecting-rods gave the motion to two pinions 

 cranks at right angles to each other ; these pinion* 

 communicating the motion to the wheel which worke< 

 into the cogged-rail. 



Mr. Blenkinsop' s engines began running on the rail-| 

 way extending from the Middleton collieries to the 

 town of Leeds, a distance of about three miles and a 

 half, on the 12th of August, 1812. They continued for 



a member of that learned body said, 



nious, no doubt, but unfortunately the 

 machine will never move ; it is too 

 heavy. The wheels will turn round 

 and round in the same place." 



1 The following is the description 



occasionally, or in certain cases, make 



smiling, " Yes, this is all very inge- the external periphery of the wheels 



uneven, by projecting heads of nails, 

 or bolts, or cross groves, or fittings to 

 railroads, when required ; and that in 

 case of hard pull we cause a lever, 

 bolt, or claw to project through the 



given in the specification of the pa- rim of one or both of the said wheels, 

 tent : " It is to be noticed that we do so as to take hold of the ground.'" 



