Coal, a great source of our wealth. 29 



estimated at about 71^ millions. In the United 

 States of America there are about five thousand 

 telegraph stations, and 75,000 miles of line, which 

 transmit yearly about 11,500,000 messages. The 

 telegrams of Great Britain number about one- 

 fourth of a million per week. The world's telegrams 

 during the year 1877 numbered nearly 130 millions ; 

 and the world's letters about 3,300 millions, or 9^ 

 millions each day. Even the little phosphorus match 

 is being manufactured and consumed at a rate 

 estimated at more than ten thousand millions 

 daily. 



Much of the wealth of this country, resulting from 

 science, has been very easily obtained by its pos- 

 sessors. That acquired by means of our coal has 

 especially been obtained without commensurate effort. 

 The amount of that substance raised in Great Britain 

 during the year 1876 was 734 millions of tons. To 

 draw upon a great stock of that mineral is like 

 drawing money from a bank, because coal, unlike 

 any other abundant substance (except wood and 

 petroline), contains in itself an immense store of 

 energy, which is evolved as heat during combustion, 

 and may be utilized. Each piece of coal contains 

 sufficient energy to lift its own weight twenty-three 

 hundred miles, but it costs only a small proportion of 

 that power to extract and raise it from the mine. I 

 do not mean by these remarks to imply that the 

 wealth accruing from this great store of power in 

 coal is derived chiefly by the owners of coal mines. 



