1826.] Sir James Hall on the Consolidation of the Strata. 307 



suited was less perfect in its structure, tasted strongly of salt, 

 and sometimes crumbled to sand when placed in water. 



Many of these early experiments were accomplished with, 

 tolerable success. But still the result was somewhat precarious, 

 and could not be announced with the confidence that I felt iix 

 presenting my former experiments to this Society. 



The cause of this uncertainty I traced to the chemical ope- 

 ration of the salt, acting as a flux upon the porcelain vessels 

 employed. This very action, I was well aware, was the main 

 agent and cause of our success, when kept within proper 

 bounds ; but, on being allowed to pass those limits, and to act 

 on the containing vessel as well as on the experiment, it de- 

 stroyed the vessel, and converted the whole into a confused 

 mass of slag. 



After numberless unsuccessful attempts, and after returning 

 again and again to the charge, with an interval sometimes of 

 years, I at last met with a quality in some of the materials to 

 me altogether unlocked for, by means of which may be obtained 

 successful results, with scarcely any risk of failure. 



I found that the action of the salt upon the substances of the 

 crucibles of clay, did not exert itself in the 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 the 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 expectations. 



Similar results, in all respects, were produced by exposing 

 pure pounded quartz to the action of the salt fumes, — and also 

 when gravel, or any other mass of loose materials, was used 

 instead of sand. 



Having now shown, in a satisfactory manner, that salt, whe- 

 ther in a dry state mixed along with loose materials, or driven in 

 fumes through them, or applied in the state of brine, and ex- 

 posed to heat, is a sufficient agent to produce a consolidation, 

 such as we see in natural sandstones and other stratified rocks, 

 it remains to be investigated, whether an adequate supply of this 

 flux may be reckoned upon in nature. 



It is well known that great diversity exists in the degree of 

 saturation of the sea by salt, at different places ; and Buffbn has 

 been at much pains in collecting examples of this diversity in 

 his geological volumes, introductory to his Natural History. It 

 is known that, in many of the communications between sea and 

 sea, a constant current sets one way, indicating that the evapo- 

 ration from the sea, to which this stream flows, surpasses in 

 quantity its supply of fresh-water from the rivers, rains, and 

 springs. This is remarkably the case with the Mediterranean, 

 into which a perpetual stream sets from the ocean, at the Gut of 



X 2 



