3Jr. Kiriuan's Ref illation of the Huttonimi Theory. 13 



never charged it upon it: fo far was I from wifhing to make 

 ufc of what Mr. Playfair called poifoncd weapons, as he un- 

 jiiftly accufes me of having done. 



It is in vain Mr. Playudr feeks to compare geology with 

 aftronomy and zoologv; neither of thele feicnces requires any 

 notice to be taken of the original conflitution of their ob- 

 je6ls, their aftual (late being very nearly the fame as their 

 primordial ftatc: but, v;hcre hybrid fpecies occur, their origin 

 never fails of being attended to. 



In geology, the cafe is very different: here we meet with 

 ohjects whole original ttate muft have been very different from 

 their actual ftate. Rocks or Ikincs prefenting regular forms 

 muft of ncceflitv have been originally in a (late from which 

 fuch forms could arife. Maffes now hardened into ftone, 

 but prei'enting the impreflions either of vegetables or of other 

 ftones, mult have been originally in a foft ftate. Calcareous 

 il(3nes filled with fhells muft have been originally in a ftatc 

 fitted for the admiflion of thofe fliells ; hence geologifts ne- 

 ccffirily recur to a Hate of inanimate nature prior to the pre- 

 fent. This is admitted by Dr. Hutton as well as by Nep- 

 tunifts; but he thinks the prefent Itate to have originated 

 from a gradual dellruition of a former, as that did from a 

 ftill more anticnt : Hill the moil antient of thcfe worlds either 

 relend^led the ijrelent, or it did not: if not, we can fay no- 

 thing of it 5 if it did, the fame difficulties muft occur, and 

 confequently its primordial ftate muft have been different 

 from its fubfo(|ucnt ftate, as this ftate is fuppofcd to have been 

 fimilar to the prefent. The cryftallized or foft ftate of our 

 prelent rocks Dr. Hutton thinks proceeded from an igneous 

 hifion of the materials of a prior world : but he cannot fup- 

 pofe tliis of the firft of thefc worlds; its fimilarity with ours 

 nnift tlierefore be otherwiCe accounted for. 



I ftiall here conclude my obfervations on Mr. Playfair's 

 obfcrvations. Controverfics managed as this has been by 

 him and Dr. Hutton, whole favourite method of anfwering 

 objections confifts in depretiating or fncering at the undcr- 

 ftanding, and undermining the credit of their author, are a 

 difgrace to philofoptiy, and I'ulliciently expofe the weakncfs 

 f}\ the caufe that obliges to have recourfc to fuch expedients. 



i> am, &;c. &c. 



Mr, Tillvcb, KlCHARD KlR\VAN, 



II. A,t 



