Page:Theophrastus - History of Stones - Hill (1774).djvu/318

 breaks into, both thee Forms. It is unwillingly I dient in a few Particulars, from an Author with whom Reaon and Obervation command me to agree in a great many: But this is a Doctrine which trikes at the Root of all accurate Knowledge in repect of this Body.

By this Account Spar would be two Things, not one: Its Atoms would have two Figures; and we hould loe the great Ditinction by which it is kept eparate from all other Bodies. I have examined this Point with all poible Attention; and find the pyramidal Figures of Spar, whether in greater or maller Pieces, to be a econdary Form; compoed always of Rhombs: But the rhombic Figure never to have any Form in its contituent Parts beide its own. The Pyramids, great or mall, eparate into Rhombs; the Rhombs never into Pyramids. The true Way of dividing Spar is, by an Acid, carefully managed; for the Parts are always eparated, before they are diolved.

It is a ingular and a jut Obervation of the ame Author, that no pentagonal Spar has ever been found; tho' Angles in mot other Numbers are frequent; but this is not to be attributed with him, to an imaginary Salt, Alcaline, and Muriatic; it rets upon a much more olid Bae: Which is, that the particular Figure of the Rhombs of Spar, admit the contructing any other angulated Form, only not pentagonal. It