Sir James Hall on the Consolidation of the Strata. 11 



of clay, did not exert itself in tbe same manner upon iron; but that a 

 large vessel of cast-iron, 18 inches deep by 10 wide, and a common gun- 

 barrel welded up at tbe breech, and open at the top, enabled me to work 

 With the heat of melting gold, without injuring the vessels, and at any 

 time to produce a perfect freestone; thus satisfying our theoretical expec- 

 tations. . , 



" Similar results, in all respects, were produced by exposing pure pound- 

 ed quartz to the action of the salt fumes,-and also when gravel, s>r any 

 other mass of loose materials, was used instead of sand." pp. 6—12. 



Sir James next proceeds to show, that if this theory of 

 the consolidation of sandstone be admitted as sound, there is 

 an adequate supply of salt to be looked for in nature, or at 

 least of brine, which is nearly the same thing. He conceives, 

 that in the Mediterranean, and other similar seas, where there is 

 a greater evaporation from the surface than supply of fresh 

 water by the rivers, rains, &c, the sea, at the bottom, will 

 gradually approach to a state of brine. And even, without 

 entering into any such theoretical explanation of how this sup- 

 ply of salt is formed, he thinks it sufficient that there are known 

 to exist in the world many large districts of rock-salt, lakes 

 and rivers of salt water, and numerous brine-springs in this 

 and other countries. 



It was objected, as Sir James tells us, to hisTheory, by a mem- 

 ber of the Royal Society, that the influence of the superincum- 

 bent ocean would, in all cases, counteract, by its coolness, the 

 effect of the heat, and prevent the formation of stone : but these 

 experiments most distinctly prove, that this effect, however 

 probable it certainly was, would not take place, since it was easy, 

 by means of his device of the gun-barrel, to look into the heart 

 of the experiment, and discover the red-hot sand under the 

 water, while, at the same time, the temperature of the brine 

 on the top was so low that the hand could be plunged into it 

 without injury. But whenever the same experiment was tried 

 with fresh water instead of brine, no exertion of heat ever pro- 

 duced a red heat. Nothing, certainly, in the history of chemi- 

 cal experiment, is more satisfactory than this ; and the ex- 

 treme simplicity of the contrivance by which so important a 

 fact has been established, instead of diminishing, only adds to 

 our admiration of that ingenuity which seems always to 



