DISCOVERY OF ALCOHOL AND DISTILLATION. 87 



sels. But, before this process could be carried out iu a practical 

 form, the modern improvements in the process of distillation had 

 to be discovered. 



Similar processes to that mentioned by Alexander of Aphro- 

 disias are described by Dioscorides and Pliny, in the first century 

 A. D., for the preparation of two liquids so different as mercury 

 and spirits of turpentine. These discoveries, also met in acci- 

 dental observations, began to make more general the ideas of the 

 industrial men and physicists of the time. Cinnabar, or sulphuret 

 of mercury, has been used from remote antiquity as a red coloring 

 matter (vermilion) ; the Romans got it from Spain, where the 

 principal mines of mercury in Europe are still situated. It was 

 early remarked that, in heating in an iron vessel to purify it, it 

 disengages vapors of mercury, which are condensed on neighbor- 

 ing objects, chiefly on the cover of the vessel. This discovery was 

 the origin of the regular extracting process, described by Dioscori- 

 des and Pliny. The cinnabar was placed in a capsule of iron in 

 the middle of an earthenware pot. The cover was sealed on, and 

 heat was applied. After the operation the cover was scraped, in 

 order to detach and collect the globules of mercury which had 

 sublimed from the capsule. Thus was obtained artificial quick- 

 silver, which the ancients supposed to have different properties 

 from natural quicksilver, or that which occurs in Nature in mines. 

 This was an illusion, the mercury being identical, whatever the 

 mode of extraction. At any rate, the process employed for the 

 extraction of mercury by vaporization is the same as that de- 

 scribed by Alexander of Aphrodisias for making sea-water po- 

 table ; and this process, as I shall shortly explain, was the begin- 

 ning of the alembic. 



Another rudimentary process, the first that was applied to the 

 extraction of an essential oil, is described by Dioscorides and by 

 Pliny. It is for the distillation of pine resins, which are now 

 called turpentines. They were heated in vessels over which wool 

 was spread ; this condensed the vapor ; then the wool was pressed, 

 in order to extract from it the liquefied product, spirits of turpen- 

 tine, which was then called resin oil or flower of resin. It soon 

 assumed an important function in the composition of the inflam- 

 mable substances used in the arts and in war. But these terms 

 seem at first to have designated also and at the same time the most 

 liquid part of the resins, as well as the water charged with their 

 soluble principles, which was floating on these resins like whey on 

 milk, at the moment of their extraction ; and, lastly, the distilled 

 and odorous water which was vaporized at the same time with the 

 essence. The ancients were in some confusion about these sub- 

 stances, which are distinct in modern chemistry ; and this it is which 

 makes the reading and interpretation of the old authors so hard. 



