174 FERGUSON'S LECTURES. 



LECT. constructed to work six pumps, capable of raising at each stroke 

 V- a load of water equal to 37,982 pounds seven feet and a half 

 ^ high ; and so perfect was its action, that a bushel of coals raised 

 46 millions of pounds one foot high. 



The application of steam engines to the propelling of car- 

 riages on the public road, has hitherto been considered as a re- 

 finement in mechanics, rather to be wished for than a matter of 

 reasonable expectation. The locomotive engine was first em- 

 ployed for this purpose by Messrs. Trevithick and Vivian, in 1802 ; 

 and it found a ready introduction to the mining districts where 

 rail roads are general. In some cases, five, six, and even ten 

 waggons laden with coal are dragged up an inclined plane by 

 means of these vehicles ; and of course impelled by a high pres- 

 sure engine, from the utter impossibility of carrying condensing 

 water in a moveable vehicle. 



An engine of four horses' power, employed by Mr. Blenkinsop, 

 impelled a carriage lightly loaded on a rail road at the rate of 

 ten miles an hour, and when connected with thirty coal wagons, 

 each weighing more than three tons, its average rate was about 

 one third of that pace. 



When the locomotive engine was first tried, it was found diffi- 

 cult to produce a sufficient degree of re-action between the 

 wheels and the tract road ; so that the wheels turned round with- 

 out propelling the vehicle. This inconvenience was, however, ob- 

 viated by Mr. Blenkinsop, who when he adopted the locomotive 

 engine, took up the common rails, on one side of the whole length 

 of the road, and replaced them by a series of racks, or rails, 

 furnished with large teeth. The impelling wheel of the engine 

 was made to act in these teeth, so that it continued to work in a 

 rack which insured a sufficient degree of re-action. 



From the great weight of an ordinary locomotive engine 

 as well as the construction of its wheel, it must be evident that 

 the employment of this species of prime mover on the public roads 

 would be in the highest degree destructive ; and as such, that its 

 use will still be partially confined to the mining districts, in which 

 the greatest facilities are offered for its general adoption. Indeed, 

 we find in one neighbourhood alone, and within a space of less 

 than thirty square miles, more than eight miles of road admirably 

 adapted for this species of conveyance ; and it is a well known 

 fact, that there are many situations in which iron rail-roads might 

 be advantageously employed, in which it would be quite im- 

 possible to open a navigable canal. In illustration o the above 

 fact, it may be proper to state, that a company, with a large capital, 



