196 president's address — section J. 



np or wasted, as science will discover some new source of 

 power ; he then showed that there is no other source of 

 power, all other material on earth having long ago combined 

 with oxygen, liberated heat, and is at rest ; organic carbon, 

 coal or wood, is the only material that is still in a state of 

 unstable equilibrium ready to combine with oxygen and give 

 out heat. 



When we consider the monstrous scale on which the con- 

 sumption of coal is carried on, the problem of its coming 

 scarcity, if not total exhaustion, will very soon become a 

 subject for practical consideration, and not, as hitherto, a 

 speculation to amuse a leisure hour. Great Britain alone 

 consumes 165 millions of tons every year; this quantity is 

 sufficient to build a wall of coal thirteen feet high and four 

 feet thick right round the world. 



It is fair to su]:)pose that the time is not far distant when 

 North and South America, China, Japan, and Australia Avill, 

 in proportion to their population, consume as much coal as 

 England does, and the quantity would be so enormous that 

 it seems incredible to snpj^ose the supply can last veiy long. 

 When our fuel is done, civihsation, as we know it, must 

 decline, as it exists only by consuming the products of tlie 

 earth faster than they can be re])laced, or using up such as 

 can never be replaced. The world will look to engineers to 

 make our stores of fuel last for an indefinite time by dis- 

 coveries in the method of turning heat into power that shall 

 take the place of the wasteful steam engine. Possijjly elec- 

 tricity may come to our aid in a new channel if the discovery 

 should be made of producing electrical energy directly from 

 heat without the use of a steam engine. 



These anticipations are in advance of our time. At present 

 the only method we have to turn heat into power is to convert 

 water into steam and use the elastic pressure of the steam for 

 our purposes. Mechanical engineers have left no stone 

 unturned to bring the steam engine to perfection, and since 

 it was invented improvements have never ceased. For a 

 long time attention was almost exclusively directed to the 

 engine, which was compounded and jacketed with steam to 

 make the most that was possible out of the expansion of the 

 steam. As economy continually called for more ex])ansion, 

 this, in its turn, demanded higher j)i'essure of steam, which 

 required a thorough re-organisation of the boiler until the 

 latest practice is to employ three, or even four, cylinder 

 engines, with steam of 160 pounds pressuiv. fresh water 



