( 37 ) to Copper, and the reft in like Manner. In his Compendium of Tranfmutation, dedicated to Robert King of England, he doth particu larly teach the Way of making artificial pre cious Stones, by a Mixture of the Waters of divers Metals, as beautiful and of the fame Virtue as the natural ones are. A Knowledge over and above other excellent Qualities of that rare Perfon, which feems to out go Hu man Capacity. But it is the eafier to be be lieved, becaufe we fee Efmalts made of divers Colours, by a Compofition of Minerals ground to Powder and Glals, and falfe Stones made in the fame Manner. Tranfparent precious Stones have many Faults in them, which by Reafon of their Clearnefs are fooner difcover’d by the Eye, than thofe in common Stones, as Spots ap pear the moil in fineft Garments ; and it is rare to find a Stone that hath not fome De feat or other; either Spots, or Hair, Cloud, Shadow, Salt, or other thing fubjetft to be engendred in them, bccaufe the Humour of which it is made is not all of one Colour. A Shadow arifes from the Humours being more obfcure in that Part. A Cloud comes from the Humours being too white in that Part. Hairs, which are ofteneft found in the Saphir, and Salt which particularly hurts the Opalos, as Lead doth the Emerald, are Impediments of different Colours from the true Colours of the Stone in which they are, CHA£.