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Until within these last hundred years, the nature of the sub- 

 stances, which form the subject of our present inquiry, was so little 

 understood ; that the most vague, and unphilosophical ideas, were 

 universally entertained respecting them. Men of considerable 

 learning, either contented themselves with the popular otions ,or, 

 substituted for them theories, still more silly and preposterous. 

 Thus our countryman Lhvvydd, in his Ichnographia Lithophylacti 

 Britannici, Langius in his Historia Lapidum figuratorum Helvetia , 

 Dr. Plott in his Natural History of Oxfordshire, and numerous other 

 writers, so little suspected the real origin of these bodies, that they 

 described their peculiar forms as the sports of nature ; or attributed 

 their formation to the action of a certain Plastic power, destined to 

 the subterranean formation, of these regularly formed concretions. 



So far was fancy indulged, whilst endeavouring to account for 

 their origin, that it was even supposed, as I remarked in my last, 

 that the seminal principles of various beings, raised by evaporation, 

 and carried by the air, or by subterranean currents, were deposited 

 in the several cavities of the bowels of the earth. These were sup- 

 posed to have grown, during an anomalous kind of life ; and to 

 have assumed a similar nature, with that of the particular matrix, 

 in which they had been deposited. 



Others among whom Tournefort and Camerarius deserve parti- 

 cular mention, fully believed in the vegetation of stones : and were 

 convinced, that their seminal principles diffused, as well through 

 the seas, as the earth, were gradually developed, and reduced into 

 their appropriate forms, by a regular apposition of their particles ; 

 somewhat in the same manner, as in the formation of regularly 

 formed crystals. Every figured stone was supposed to have had 

 its peculiar seed, its nourishment, and its growth. The beautiful 

 and variously formed stalactites, which adorn the subterraneous 

 caverns of Derbyshire, and of many other parts of the world, were 

 supposed to be proofs of this species of vegetation; since their 



