302 Sir James Hall on the Consolidation of the Strata. [Oct. 



of submitting to a variety of chemical tests ; being for ever on 

 the watch for sucli natural scenes as might illustrate these prin- 

 ciples, as well as for opportunities of making experiments, to 

 determine whether such modifications on the action of heat 

 were, or were not, sufficient to justify the expectations of Dr. 

 Hutton. 



It was in prosecution of these views that I formerly under- 

 took a set of experiments, proving, I believe to the satisfaction 

 of the scientific world, the identity of Whinstone and Lava, of 

 which a full detail is given in your Transactions. In farther 

 illustration of the same topic, my experiments on Carbonate of 

 Lime were formerly undertaken, by which it was shown, that 

 calcareous matters, exposed to heat under pressure, might be 

 fused ; and, on cooling, would crystallise, so as in every respect 

 to resemble marble. To these I beg leave likewise to refer the 

 Society. 



The immediate object of the paper I have now the honour of 

 submitting to the Society — the consolidation of the strata — has 

 been pursued in a similar spirit, and with similar views to those 

 formerly announced. In making efforts to trace the modifica- 

 tions which the action of heat would undergo, when compelled 

 to act under the influence of compression, or of other circum- 

 stances, all of which, in company, I have always been willing 

 to distinguish by the name of Plutonic, (although the term was 

 originally suggested, ironically, by one of our keenest antago- 

 nists, the late celebrated Dr. Kirwan), I was led to the par- 

 ticular topic of this paper, by an unexpected scene which pre- 

 sented itself in my own neighbourhood, in the country. 



It had often been urged, and apparently with good reason, 

 against this branch of the Huttonian Theory, that no amount of 

 heat appHed to loose sand, gravel, or shingle, would occasion 

 the parts to consolidate into a compact stone. And as all my 

 experience led to the same conclusion, I saw that, unless, along 

 with heat, some flux were introduced amongst the materials, no 

 agglutination of the particles would take place. The striking 

 circumstance above alluded to, as occurring near Dunglass, and 

 which will be particularly described presently, having suggested 

 to me the idea that the salt of the ocean might possibly have 

 been the agent in causing the requisite degree of fusion, 1 insti- 

 tuted a series of experiments, the details of which I am about 

 to bring before the Society. By these, I conceive it will be 

 shown, that this material, under various modifications, is fully 

 adequate to explain the consolidation of the strata, and many 

 other effects which we see on the surface of the Earth. 



My success, from the first, was such as to promise the most 

 satisfactory result, though it is only within the last year that I 

 have been able to command the repetition of the experiments 



