PLASTIC FORCE 235 



mortuum of the Cinnabar of Antimony. To such a Salt 

 may also be referred our Brontice or Ombrice, and all 

 the Echinites, some whereof are plainly, all in some 

 measure stellated at the Top. 



" The Belemnites, which are all striated from a Center, 

 yet in the whole affect a Pyramidal Form, seem to have 

 somewhat also of an Antimonial, but a more prevalent 

 Quantity of a Nitrous Salt. 



" The Conchites, Pectinites and Ostracites, whether 

 transversely striated, or from the Commissures to the 

 Rim, seem to owe their origin to Urinous Salts, which 

 start likewise from a Center (as suppose from the Hinges 

 of these Stones), but generally are most extended to one 

 side, as may be seen in the branched Figure formed 

 on the Surface of Urine by freezing, as in Mr. Hook's 

 Micrography, whose Stria not obtaining much above 

 the Quadrant of a Circle, whatever other Differences 

 they may be, in this respect at least is agreeable to 

 our Stones. 



" To which add the Ophiomorphit's or Cornua Ammonis, 

 most probably formed either by the Salts shooting dif- 

 ferent ways, which by thwarting one another make a 

 Helical Figure, just as two opposite Winds or Waters 

 make a Turbo, or else by some simple, yet unknown 

 Salt, that affects such a Figure : perhaps the Stems 

 and Branchings bended in a most excellent and regular 

 Order, like the ribs of some of our Ophiomorphit's, 

 observed by Mr. Hook in Eegulus Martis Stellaris, 

 might not a little conduce to the clearing of this 

 Matter." 



The difficulties which beset this explanation are duly 

 considered and disposed of ; the last of them is so 

 quaintly treated that I cannot forego the pleasure of 

 quoting it. " That it seems quite contrary to the in- 

 finite Prudence of Nature, which is observable in all 



