STEAM. 



The circumference of the earth measures twenty-five thousand 

 miles ; if it were begirt with an iron railway, such a train as 

 above-described, carrying two hundred and forty passengers, 

 would be drawn round it by the combustion of about three 

 hundred tons of coke, and the circuit would be accomplished in 

 five weeks. 



28. The enormous consumption of coals produced by the appli- 

 cation of the steam-engine in the arts and manufactures, as well 

 as to railways and navigation, has of late years excited the fears 

 of many as to the possibility of the exhaustion of our coal-mines. 

 Such apprehensions are, however, altogether groundless. If the 

 present consumption of coal be estimated at sixteen millions of 

 tons annually, it is demonstrable that the coal-fields of this country 

 would not be exhausted for many centuries. 



But in speculations like these, the probable, if not certain 

 progress of improvement and discovery ought not to be overlooked ; 

 and we may safely pronounce that, long before such a period of time 

 shall have rolled away, other and more powerful mechanical agents 

 will supersede the use of coal. Philosophy already directs her finger 

 at sources of inexhaustible power in the phenomena of electricity 

 and magnetism. The alternate decomposition and recomposition 

 of water, by electric action, has too close an analogy to the alter- 

 nate processes of vaporisation and condensation, not to occur at 

 once to every mind : the development of the gases from solid 

 matter by the operation of the chemical affinities, and their sub- 

 sequent condensation into the liquid form, has already been 

 essayed as a source of power. In a word, the general state of 

 physical science at the present moment, the vigour, activity, and 

 sagacity with which researches in it are prosecuted in every 

 civilised country, the increasing consideration in which scientific 

 men are held, and the personal honours and rewards which begin 

 to be conferred upon them, all justify the expectation that we are 

 on the eve of mechanical discoveries still greater than any which 

 have yet appeared ; that the steam-engine itself, with its gigantic 

 powers, will dwindle into insignificance in comparison with the 

 energies of nature which are still to be revealed ; and that the day 

 will come when that machine, which is now extending the blessings 

 of civilisation to the most remote skirts of the globe, will cease to 

 have existence except in the page cf history. 



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