[ '5S ] 



of many other manufadures, as well as to fnpplying the immenfc 

 confumption of the capital. It is a happy circumftancc that the 

 obfervations that lead to its invcfligation are, of all others, the 

 leaft fallible and ambiguous. To colled thefe, I have perufed all 

 thofe hitherto made on coal-mines, and the ftrata that ufually 

 accompany them. The moft important, and which may ferve 

 to guide us in our refearches, being but few, and perhaps not 

 generally known, at leaft in this kingdom, I take the liberty of 

 laying before the Academy, to which every attempt to promote 

 the public utility, however deftitute of merit in other refpeds, 

 cannot fail of being acceptable. 



General Obfervations. 



When wc confider the interior conftrudion of mountains, 

 hills or plains, and the materials of which they confift, we are 

 eafily led to acknowledge not only that the greater part were 

 formed in water, but that fome of them are of later formation 

 than others. Thus fome are formed of huge Ihapelefs mafTcs, 

 without any regular fiffures ; but if thefe mafles be attentively 

 infpeded, they will be found to confift of fmall grains of ftones, 

 of different forts, concreted together, and hence called granites j 

 the exad adaption of thefe grains to each other, and the regular 

 cryftallized fhape of fome of them, rtiew that they muft have 

 been originally in a foft or even in a fluid ftate ; their continuity, 

 and want of regular fiflures, indicate their fimultaneous concre- 

 tion ; the fuperior difficulty of their folution at prefent, and 

 the immenfc fpace they occupy in the globe, of which they 



conftitute 



