806 Sir James Hall on the Consolidation of the Strata, [Oct. 



flux on the siliceous matter, and thus cement the adjacent par- 

 ticles together. The Society are, doubtless, well aware of tha 

 power of salt fumes in glazing pottery ; and the analogy, I con- 

 ceive, is complete. It is the application alone that is new. 



So far the results were satisfactory. But it next occurred, 

 that it might be plausibly objected, that the presence of the su- 

 perincumbent cool ocean would interfere with the process, on 

 the principles of latent heat. To put this to the test, I pro- 

 ceeded to expose a quantity of sand, covered to the depth of 

 several inches with common salt-water, to the heat of a furnace, 

 and, as the liquid boiled away, replenished it from time to time 

 by additions from the sea. Of course it gradually approached 

 to a state of brine. But this proved a very tedious operation, 

 requiring a continued ebullition, during three weeks without 

 ceasing, before it became sufficiently saturated with salt by the 

 discharge of the fresh-water; and I thought it much easier, 

 and no less satisfactory, to employ brine from the first, formed 

 at once by loading the water with as much salt as it could dis- 

 solve, amounting to about one-third of its weight. 

 * The vessels employed in these early experiments were the 

 large black-lead crucibles used by the brass-founders. I filled 

 the vessel, which was 18 inches high and 10 broad, nearly to the 

 brim with brine of full saturation, the lower portion being occu- 

 pied, to the depth of about 15 inches, with loose sand from the 

 fiea-shore, and thoroughly drenched with the brine. In order 

 to have a view of the progress of the experiment, I placed an 

 earthen-ware tube, about the size and shape of a eun-barrel, 

 closed at bottom, and open at the top, in a vertical position^ 

 having its lower extremity immersed in the sand, and reaching 

 to within about an inch of the bottom of the pot, while the 

 other end rose a foot above the surface of the brine, and could 

 be looked into without inconvenience. 



After a great number of experiments, furnishing an unbounded 

 variety of results, I at length obtained a confirmation of the 

 main object in view. I observed that the bottom of the porce- 

 lain barrel, and of course the sand in which it rested, became 

 red-hot, whilst the brine, which, during the experiment, had 

 been constantly replenished from a separate vessel, continued 

 merely in a state of ebullition : the upper portion of the sand, 

 drenched with the liquid, remained permanently quite loose, 

 but the lower portion of the sand had formed itself into a solid 

 cake. 



On allowing the whole to cool, after it had been exposed to a 

 high heat for many hours, and breaking up the mass, I was 

 delighted to find the result, occupying the lower part of the pot, 

 possessed of all the qualities of a perfect sandstone, as may be 

 seen in the specimens now presented to the Society. Whenever 

 •the heat was not maintained so long, the sandstone which -re- 



