SIR JAMES HALL on the Consolidation of the Strata. 317 



the case may be very different, where that same cause acts at 

 the bottom of a deep sea, and under various modifying circum- 

 stances, by which its operation could not fail to be influenced. 



This, indeed, constitutes the essence of the Huttonian Theo- 

 ry, which I learned principally in conversation with its illustrious 

 author ; and which, since his death, I have taken every means of 

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

 watch for such natural scenes as might illustrate these principles, 

 as well as for opportunities of making experiments, to deter- 

 mine whether such modifications on the action of heat were, 

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



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

 took a set of experiments, proving, I believe to the satisfac- 

 tion of the scientific world, the identity of Whinstone and 

 Lava, of which a fuh 1 detail is given in your Transactions. In 

 farther illustration of the same topic, my experiments on Car- 

 bonate of Lime were formerly undertaken, by which it was 

 shewn, 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 re- 

 fer 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 ori- 

 ginally suggested, ironically, by one of our keenest antagonists, 

 the late celebrated Dr KIR WAN), I was led to the particular topic 

 of this paper, by an unexpected scene which presented itself in 

 my own neighbourhood, in the country. 



