Of XFO ^T>^SHI\E. 7 



of there are foriie in the Quarrys near Shot over, fo clear and hard, 

 that they come not much behind the Briflol-ftones, and are in fi- 

 gure (though had from the fame Quarry) as various as Viamants ; 

 fome of them being comprifed in/even, others in nine, others in 

 eleven, and fome in thirteen planes, as may eafily be computed 

 from their trigonal, tetragonal, pentagonal, and hexagonal pyramids, 

 reprefented in Tdb.^.Fig.io. to which, adding theplanes of their 

 columns, and the planes of their bafts, whereby they are fix'd to 

 their fubjefts, thofe numbers of Hedr* rftuft needs be concluded* 



52. As to the origin and texture of Spars, I take them to be 

 much of the fame with Chryftals (though we feldom find them 

 of their hexagonal figure, or their columns ever interceding two 

 pyramids') and that they differ in lufter and hardnefs according t6 

 the more clofe or loofe texture of the/tones whereon they fit, and 

 out of which they have fw eat? as through a ftrainer or colanden 

 Though it muft not be denyed, but what is arTerted by the inge- 

 nious and obferving Steno' 1 concerning Chryflals, may haveplac 

 alfo in the increafe and growth of thefe, which he fays (what- 

 ever may be the manner of their firft delineation) is by external 

 appofition of new Chryjlalline matter to the external planes of the 

 already delineated Chryftal; which he alfo obferves, not to b 

 joined to all its planes, but for the moftpartto the//<772wof the 

 top only ; nor to thefe all at a time, nor in the fame quantity. 

 Whence it is, that the extream or top planes of Spars as well as 

 Chryflals, axe feldom of never equal, and not always triangular, 

 but rifing with unequal fides and angles from the planes of their 

 columns, as in that feparate piece of Spar or Chryftal near Fig. 10. 

 which I take to be arguments furn'cieritly concluding the ftmilitudi 

 of their growth and texture of parts, notwithstanding the planes 

 of the columns of Spars ate notftreaked, nof fo plainly ihew the 

 places of appofition, as they do on Chryftal ; which ftreaks, for 

 the Readers more ready apprehenfion, are therefore cut on the fe- 

 parate column near Fig. 1 o. though otherwife indifferently to be 

 underftood either for Spar or Chryjlall. 



53. Some of thefe Spars fall fo little fliort, either of Chryftals 

 or BriflolDiamants, either in lufter or hardnefs, that we may very 

 welladmit what is faid of them by Aldrdvandtis*, that they are 

 gemm& inchoate, is- non perjeft*. And that Boetim h in all likely. 



1 Vrodrem. de Chryftallo-propo[itionil>. i. 2, 3. * Mufisum Metall.lib. 4.. **/>. 76. b DeLapid.& 

 Gem. cap. 304.. 



N hood 



