OF HEAT. 155 



terrible in its heat that all the vegetation is on fire, 

 and the abodes of mankind crumbling into powder at 

 a considerable distance before its march of terrific 

 desolation. So also, if it is situated under the sea, 

 no matter for the depth, let there be but heat enough, 

 and the substance which opposes that will be sent 

 burning to the atmosphere, although the very depth 

 of mid-ocean lie between. Indeed, the water tends 

 in two ways to facilitate the ascent of the submarine 

 volcano. First, it consolidates the external crust 

 by cooling it, and thus prevents the spread of the 

 matter over the bottom ; and, in the second place, 

 as water presses in proportion to the depth, and 

 presses equally in all directions, the pressure on the 

 .top of any mass is less than the pressure upon an 

 equal portion on one of the sides. Thus, there is a 

 considerable resemblance between the ascent of a 

 volcanic column through the water of the sea, and 

 the ascent of a column of smoke through the air ; 

 and so, by means of the cooling influence and pres- 

 sure of the water acting jointly, buildings may be 

 erected there far more gigantic than any which man, 

 or any power of nature with which we are ac- 

 quainted, could erect upon the land. 



Those who look at the productions of nature, 

 without taking nature's powers of producing into 

 the account, are in the habit of considering it a very 

 marvellous thing to find shells and other productions 

 which are not only of the sea, but of the very depths 

 of the sea, near the summits of some of the loftiest 

 mountains on the surface of the earth ; but truly it 

 it is difficult to imagine how the case could be other- 

 wise ; for there is nowhere on the globe an apparatus 

 in which great mountains could be manufactured but 

 just the great ocean ; and it is very likely that so 

 much of the earth's surface is covered with the 

 ocean just in order that those powers with which 

 the Almighty has endowed matter for the accom- 

 plishment of his pleasure, and which, measureless 



