400 WORK DONE BY STEAM ENGINES. 



ing which Coal, and the steam engine, alone supply. It 

 would be quite impossible to procure the fuel necessary for 

 these engines, from any other source than mineral coal. 



The importance of Coal should be estimated, not only by 

 the pecuniary value of the metals thus produced, but by their 

 farther and more important value when applied to the in- 

 tinitely varied operations and productions of machinery and 

 of the arts. 



It has been calculated that in this country about 15,000 

 steam engines are daily at w^ork ; one of those in Cornwall 

 is said to have the power of a thousand horses,* the power 

 of each horse, according to Mr. Watt, being equal to that 

 of five and a half men; supposing the average power of 

 each steam engine to be that of twenty-five horses, we 

 have a total amount of steam power equal to that of about 

 two millions of men. When we consider, that a large pro- 

 portion of this power is applied to move machinery, and 

 that the amount of work now done by machinery in Eng- 

 land, has been supposed to be equivalent to that of between 

 three and four hundred millions of men by direct labour, 

 we are almost astounded at the influence of Coal and Iron, 

 and Steam, upon the fate and fortunes of the human race. 

 " It is on the rivers," (says Mr. Webster,) " and the boatman 

 may repose on his oars ; it is in highways, and begins to 

 exert itself along the courses of land conveyances ; it is at 

 the bottom of mines, a thousand (he might have said, 1800) 

 feet below the earth's surface ; it is in the mill, and in the 



* Wlien Engineers speak of a 25 horse Engine, they mean one which 

 would do the work of that number of horses constantly acting, but supposing 

 that the same horses could work only 8 hours in every 24, there must be 75 

 horses kept at least to produce the effect of such an Engine. 



The largest Engine in Cornwall may, if worked to the full extent, be 

 equal to from a 300 to 350 horse power, and would therefore require 1000 

 horses to be kept to produce the same constant effect. In this way it has 

 been said than an Engine was of 1000 horse power, but this is not accord- 

 ing to the usual computation. 



Letter from J. Taylor, Esq. to Dr. Buckland. 



