Sir James Hall on the Consolidation of the Strata. 9 



ing the boiling point of brine. But no sooner was this dryness accom- 

 plished, than, I imagined, the temperature of the mass would begin to rise 

 above that pitch ; the portion of it next the fire would gradually acquire a 

 red-heat ; that then the salt, being made by the heat in part to assume an 

 elastic form, would be sent in fumes through the dry cake just described, 

 and thus, by partially melting the contiguous particles, produce an agglu- 

 tination. 



" Such being my theoretical views, no time was lost in submitting 

 them to the test of experiment. Taking it for granted that a quantity of 

 sea-salt must frequently be formed and deposited, along with sand and 

 gravel, at the bottom of the ocean, (in the manner I shall have occasion to 

 describe at another stage of this paper), where the water has been collect- 

 ed by its superior specific gravity, in the form of brine, I proceeded to 

 make the following experiments: — 



" Dry salt was placed along with sand, sometimes in a separate layer, 

 at the bottom of the crucible, and sometimes mixed throughout the expe- 

 riment : the whole was then exposed to heat from below. I found that 

 the salt was invariably sent in fumes through the loose mass, and by its 

 action produced solid stone in a manner completely satisfactory, as illustra- 

 tive of the facts in Aikengaw ; and so as to give a good explanation of the 

 production of sandstone in general. 



" These artificial stones are of various degrees of durability and hard- 

 ness; — some of them do not stand exposure to the elements, and crumble 

 when immersed in water ;— some resist exposure for years ; — others are 

 so soft as not to preserve their form for any length of time ; — while some 

 bear to be dressed by the chisel : and, it may be remarked generally, that, 

 as far as the results of my experiments have been compared with natural 

 sandstone, the same boundless variety exists in both cases. A striking in- 

 stance of this resemblance occurs in the case of the Salt-heugh, the sand- 

 stone of which, when immersed in water, crumbles down, exactly in the 

 same manner as those results of my experiments which taste much of 

 salt. 



" The fumes of the salt, no doubt, act, in all these cases, as a flux on the 

 siliceous matter, and thus cement the adjacent particles together. The So- 

 ciety are, doubtless, well aware of the power of salt fumes in glazing pot- 

 tery ; and the analogy, I conceive, 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 superincumbent cool 

 ocean would interfere with the process, on the principles of latent heat. 

 To put this to the test, I proceeded 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 suffi- 



