PEYSSONNEL AND BAKER. 139 



the different proportions of mineral saline particles of 

 the stony or other matter with which they are blended, 

 and of marine salt, which must have a considerable 

 share in such formations, may occasion all the variety 

 we see. Nor does it seem more difficult to imagine 

 that the radiated, starry, or cellular figures along the 

 sides of these corals, or at the extremities of their 

 branches, may derive their production from salts in- 

 corporated with stony matter, than that the curious 

 delineations and appearances of minute shrubs and 

 mosses on slates, stones, &c. are owing to the shoot- 

 ings of salts intermixed with mineral particles ; and 

 yet these are generally allowed to be the work of 

 mineral steams and exhalations, by which must, I 

 think, be meant the finest particles of some metal or 

 mineral incorporated with, and brought into action 

 by, a volatile penetrating acid, which, carrying them 

 along with it into the fissures at least, if not into the 

 solid substance, of such stones or slates, there deter- 

 mines them to shoot into these elegant branchings, 

 after the same manner, and frequently in the same 

 figures, as the particles of mercury, copper, &c. are 

 disposed and brought together by the salts in aqua 

 fortis*." 



Such was the murky atmosphere of Nature's labo- 

 ratory, in which our countryman, John Ellis, found 

 himself plunged when he first undertook his work on 

 British Zoophytes such was the Stygian gloom his 

 labours dissipated. We ought, indeed, to apologize 

 to our readers for detaining them so long from the 



* " Employment for the Microscope," pp. 2ia~220. Lond. 

 1753. 



