FORCE OP ITS ASCENT. 245 



Now, if we suppose that the surface, acted under 

 by the heat, was only a circle of about one hundred 

 and twenty fathoms in diameter, we shall form a 

 rude estimate of the power employed. The surface 

 is about 11,310 square fathoms, or 407,160 square 

 feet, or 56,631,040 square inches, which at three 

 hundred weight on the square inch, gives a pressure 

 from the weight of the water alone of the vast 

 amount of 8,794,656 tuns. But as there were other, 

 and probably greater, resistances to overcome, the 

 force exerted at that single spot must have been far 

 greater than would suffice to blow all the navies in 

 the world into the air. That spot, too, was but a 

 mere point on the surface of the globe ; so that it is 

 utterly impossible to imagine any material weight, 

 or material strength, which those powers could not 

 overcome. 



It is only under the pressure of a depth of water 

 that such a phenomenon could take place, as the 

 water both supports and consolidates the upper part, 

 and so enables the crust to rise in a mass, which, in 

 the air, would burst and discharge the melted matters 

 in an eruption, as is the case in those volcanoes that 

 are on land. 



The second observation of Hotham Island was 

 made on the 13th, two days after the first ; and the 

 account was, the appearance of columns of smoke, 

 the hearing of a sound like that of the paddle-wheels 

 of a steamboat ; and dark matter rising up to a 

 height, and then falling with force into the sea : all 

 those appearances, which we have stated in nearly 

 the words of the eyewitnesses, agree in establishing 

 the same fact; namely, that by that time the vol- 

 canic matter had reached the surface, and been broken 

 when it came in contact with the air, or even when 

 so near the surface that the pressure upon it was 

 much diminished. The smoke was a sure sign thai 

 the surface was reached, the hissing was the solid 

 matter coming in contact with water at a lower 

 X2 



