io HISTORICAL INTRODUCTION TO CHEMISTRY CHAP. 



" Commonly in all fat soils or clayey grounds, especially 

 in the white, there is found a kind of stones, round or oval 



in form Which if it is cleansed from the earth, 



and beaten to pieces, looks within of a fair yellow and in 

 streaks, like a gold Marcasite, or a rich gold Ore, but there 

 is no other taste to be perceived in it, than in another 

 ordinary stone ; . . . . Now this stone is nothing else, but 

 the best and purest Mineral (or Ore) of Vitriol, . . . out of 

 which there may be made an excellent medicine, as 

 followeth. 



Take this Ore or Mineral beaten into pieces, and for some 

 space of time, lay or expose it to the cool air, and within 

 twenty or thirty days it will magnetically attract a certain 

 saltish moisture out of the air, and grow heavy by it, and at 

 last it falleth asunder to a black powder, which must remain 

 further lying there still, until it grow whitish, and that it do 

 taste sweet upon the tongue like vitriol. Afterward put it in 

 a glass vessel, and pour on so much fair rainwater, as that it v 

 cover it one or two inches ; stir it about several times in a 

 day, and after a few days the water will be coloured green, 

 which you must pour off, and pour on more fair water, and 

 proceed as before, stirring it often until that also come to be 

 green : this must be repeated so often, until no water more 

 will be coloured by standing upon it. Then let all the green 

 waters which you poured off run through filtering paper, for 

 to purify them ; and then in a glass-body [ i.e., a retort ] cut 

 off short let them evaporate till a skin appear at the top : 

 then set it in a cold place, and there will shoot little green 

 stones, which are nothing else but a pure vitriol : the re- 

 maining green water evaporate again, and let it shoot as 

 before : and this evaporating and crystallising must be 

 continued until no vitriol more will shoot " (Philosophical 

 Furnaces ; Part II. 1651, p. 71 ; Works, 1689, I. 21). 



SUMMARY AND SUPPLEMENT 



Scientific Chemistry begins with Robert Boyle (1627-1691), 

 but was preceded by three periods, namely : 



(i) An Ancient Period, extending up to the Christian era, 

 in which many primitive manufactures were developed ; 



