9 o THE POPULAR SCIENCE MONTHLY. 



the elixirs, but they also made it practicable to collect the liquids 

 placed in the alembics. 



At last, however, the operators of the middle ages perceived 

 that the manipulations could be conducted more rapidly, the dis- 

 tillations, for instance, by cooling the cap and the connected tube 

 that conducted to the last receiver. For that purpose they first 

 fixed around the boiler cap a bucket filled with cold water ; this 

 facilitated the condensation, but caused a part of the liquefied 

 vapors to fall back into the boiler. A new improvement the one 

 described by Porta consisted in bending the tube between the 

 cap and the receiver and giving it the form of a serpent. This 

 was the origin of the modern still-worm. It was surrounded by 

 cold water in a wooden vessel. But the use of the serpentine ar- 

 rangement spread very slowly, and was still regarded as recent by 

 the authors of the eighteenth century. 



Let us observe here that we are using the word distillation in 

 the modern sense of evaporation followed by a condensation of 

 liquid ; but in many authors of the middle ages the sense is more 

 vague. The word means, in its literal sense, a flow drop by drop, 

 and is applied equally to filtration and all refining and purifica- 

 tion. The word distill is often employed in the same sense in 

 modern language. It also comprehended from the Greco-Egyp- 

 tian epoch two fundamentally distinct operations, viz., the con- 

 densation of dry vapors into a solid form such as calamines or 

 metallic oxides, sulphur, metallic sulphurets, arsenious acid and 

 metallic arsenic (which was the second mercury of the Grecian 

 alchemists), and at a later date chlorides of mercury, sal ammo- 

 niac, etc. the process which is now called sublimation. It re- 

 quires special apparatus, which the ancients devised and used, and 

 which gave rise to the Arabian aludel. We mention this here on 

 account of its connection with many modern industries, although 

 it has no relation to the discovery of alcohol. 



I proceed now to describe distilled liquids and the successive 

 steps made in their study. " Celestial things above, terrestrial 

 things below," was the phrase by which the Grecian alchemists 

 designated the products of all distillation and sublimation. They 

 declared that "the sublimed vapor emitted from below up is 

 called divine. . . . White mercury is likewise called divine, be- 

 cause it, too, is emitted from below up. . . . The drops which 

 affix themselves to the covers of boilers are likewise called di- 

 vine." In this expression we find the marks of Aristotle, Dios- 

 corides, and Alexander of Aphrodisias. The alchemists, accord- 

 ing to their usage, interpreted these purely physical ideas by 

 symbols and a curious mysticism. Democritus (or the alchemic 

 author who took that name) called the spherical apparatus in 

 which the distillation of water was carried on " celestial natures." 



