ARABIAN AND MEDIEVAL SCIENCE. 



79 



experiments related to the calcination of quicksilver, of which he states 

 six pounds heated for eight days gained in weight three pounds. This 

 increase was largely over-estimated by Eck, although he clearly proved 

 the fact of the augmentation, which he explained by supposing that in 

 the calcination a spirit (spiritus) is united to the body of the metal, and 

 he mentions as proof of this, that when the calx is submitted to distil- 

 lation a spirit is disengaged. We shall show that more than three cen- 

 turies after these observations of the German alchemist were made, the 

 the same experiments became in the hands of Priestley and Lavoisier 

 the starting-point of modern chemistry. 



The writings of BASIL VALENTINE, also a German of the fifteenth 



FIG. 31. ALEMBIC- AND RECEIVER. 



century, contain the earliest records of several important chemical pre- 

 parations and operations. He first made known the properties of the 

 metal antimony; the preparation of "spirits of salt" (i.e., hydrochloric 

 acid) by the distillation of common salt with green vitriol (i.e., sulphate 

 of iron) ; the extraction of metals in the " wet way" as when a piece 

 of iron is immersed in a solution of copper ; the distillation from beer 

 of spirits of wine, and the concentration of the spirit : and, most re- 

 markable of all, the discovery of ether by distillation of oil of vitriol 

 with spirits of wine. 



Many of the most commonly used processes of the modern chemist 

 were practised by the alchemists, who contrived for the purpose, 



