200 INTRODUCTION 



unwearied Industry, led us on a great way in the knowledge of 

 another of the great Masses, the AIR, though the same also hath 

 not been unmindful of considering this very subject, here treated of ; 

 forasmuch as He, before he would see or hear any thing of this 

 Prodromus, did upon occasion candidly declare to the Author of 

 this Version, (who bona fide here publickly attests it,) 



" First, That he doth, upon several inducements, suppose, the 

 generality of Transparent Gems or Precious Stones to have been 

 once Liquid substances, and many of them, whilst they were either 

 fluid, or at least soft, to have been imbraced with Mineral Tinctures, 

 that con-coagulated with them ; whence he conceiveth, that divers 

 of the real qualities and vertues of Gems (for he doubts, most 

 ascribed to them are fabulous) may be probably derived. And 

 as for Opacous Gems and other Medical Stones, as Bloud-Stones, 

 Jaspers, Magnets, Emery, etc. He esteems them to have, for the 

 most part, been Earth (perhaps in some Cases very much diluted 

 and soft,) impregnated with the more copious proportion of fine 

 Metallin or other Mineral Juyces or Particles; all which were after- 

 wards reduced into the forme of Stone by ^e supervenience (or the 

 exalted action) of some already in-existent petrescent liquor or 

 petrifick Spirit, which he supposeth may sometimes ascend in the 

 forme of Steams ; from whence may be probably deduced not only 

 divers of the Medical Vertues of such stones, but some of their 

 other Qualities, as Colour, Weight, etc. and also explained. How it 

 may happen what He hath (and, he doubts not, others may have 

 also) observed of Stones of another kind, or Marcasites, or even 

 Vegetable and perhaps Animal substances, that have been found 

 inclosed in solid Stones ; For, these Substances may easily be con- 

 ceived to have been lodged in the Earth, whilst it was but Mineral 

 Earth or Mud ; and afterwards to have been, as 'twere cased up by 

 the supervenient Petrifick Agents that pervaded it.^ 



" Nor are these Petrescent liquors the only ones, to which he sup- 

 poseth that many Fossils may owe their Origin, since he thinks, 



don, 1725, pp. 15-98. The edition of Boyle's works by Thomas Birch (first edition, 1744, in 

 five volumes, the second, 1772, in six) has not been accessible to me. 



' " Of these Pretious Stones this Noble Philosopher was pleased to leave with the Publisher 

 a Manuscript of his composure, now ready to be Printed, which he assur'd him it had been 

 several Years ago." 



H. O. refers to Boyle's The Origin and Virtues of Geim, published in 1672. Cf. Shaw, 

 VoL III, pp. 99-143, and above, p. 198. 



