372 SECTION MECHANICS. 



pany's S.S. Pera, by which I have had the pleasure of travelling), is 

 now before me. 



I will conclude this part of the subject by saying, that to the com- 

 bination of science and sound practice is due the fact of the con- 

 sumption of coal having within the last ten years been reduced in the 

 marine engine from 5 Ibs. per gross indicated horse-power per hour 

 to an average of 2% Ibs., and in exceptional instances to as small a 

 quantity as i^lbs. per horse per hour. 



Let us now devote a little of the time that is left to the considera- 

 tion of the locomotive on the common road as well as on the railway. 

 I have before me, No. 2145, a model of the actual Cugnot engine in 

 the Conservatoire des Arts et Metiers, which, in 1769, journeyed, 

 slowly it is true, but did journey, and did carry passengers along the 

 roads in Paris. 



It is a most ingenious machine ; it has three wheels, and the motive 

 power is applied to the front the castor or steering wheel so that 

 engine and boiler turn with the wheel, precisely as within the last few 

 years Mr. Perkins has caused the engine and boiler to turn with the 

 steering wheel of his three-wheeled common road locomotive. The 

 steam makes the pistons in a pair of inverted single acting cylinders to 

 reciprocate, and their rods, by means of ratchet wheels, give rotary 

 motion to the castor wheel, and thus propel the carriage. I think 

 there is no doubt but what we must look upon this engine of Cugnot 

 as the father of steam locomotion in the same way as we must regard 

 Symington's engine as the parent of marine propulsion. I have before 

 me, No. 1926, Trevethick's engine of 1802. I have also before me a 

 Blenkinsop rail, one that has been in actual use for many years, 

 provided, as you will see, with teeth, into which a cogged flange 

 on the side of the driving wheel, geared, to insure that adequate 

 traction should be obtained. This plan has been revived within the 

 last few years, to enable the steam locomotive to climb the Righi. A 

 sketch of the Righi engine and rail is on the wall. It will be seen 

 that in the Righi instance the teeth, instead of projecting, as in the 

 Blenkinsop plan from the side of the rail, are ranged between two- 

 parallel bars, like the rungs of a ladder. 



On the ground floor of the Exhibition we have the veritable 



