172 The Natural Hijiory Part I 



Colour^ or outward Appearance^ is not 

 at all to be trufted. A common Mar-^i 

 e^te or Pyrites fliall have the Colour 

 of Gold moft exaftly : and fliioe with 

 all the Brightnels of it, and yet upoa 

 tryal, after all, yield nothing of worthy 

 but Vitriol , and a little Sulphur : 

 whilfl: another Body, that hath only 

 the Refemblaoce of an ordinary Peble^ 

 fhall yield a confiderable quantity of 

 Metallick and valuable Matter. So 

 likewife a Mais, which, to the Eye, 

 appears^ to be nothing but meer fimple 

 Ear«h, jliall, to the Smell or Tafte, 

 difcover a plentiful Admixture of Sul- 

 phur, Alum, or fome other Mineral 



Nor may we with much better Se- 

 curity rely upon F/^^re, or. external 

 Form. Nothing more uncertain and 

 Varying. 'Tis ufual to meet with the 

 very fame Metall or Mineral, naturally 

 ITiot into quite different Figures : as 

 ^^tis to find quite different kinds of them 

 all oi the fame Figure* And a Body, 

 that has the ihape and appearance of a 

 Diamond, may prove, upon Exami- 

 nation, to be nothing but Cryftal, or 

 Seknitis : nay perhaps only: common 

 Salt, -or Alum, natoraliy cryftallized 

 m4 'febt iota that Form. ' 3 



