Diweil die Geister, so uber sich get He ben werden, vil reyner und subtiler seind, denn in solchem aufsteigen alles, so schwer, irdisch oder flegmatisch ist, nit hinauf kom-men mag. Darumb die Geyster des weins am fluch-tigsten uber sich, aber anderer materi, so mehr mit flegmatischer feucht behafft, under sich getrieben werden.1)
The perfection of the apparatus for the preparation of distilled waters and oils, which up to that time had received but little attention, seems to have progressed much more slowly and with greater difficulty. In comparison with the readily volatile alcohol, water was considered as that product of distillation most closely related to it, whereas the oil was regarded as the "obese and fatty substance that had to be driven over with a stronger and more violent heat." This had led to the firmly established belief that in the process of purification the volatile and subtle part must penetrate and exhaust the material as much as possible (resolving). As a result all sorts of queer apparatus and sources of heat were invented for producing the so-called circulation. They all resulted in a prolonged digestion and an unintentional loss of the alcohol, ofttimes formed by fermentation, and of the aroma.
1) Hieronymus Brunschwig's De arte destillandi. Vol. 2, liber 1.
Circulation was therefore considered not only as the essence of distillation, but also as an important preparatory part of it. It was believed that the plant and animal material finally to be distilled was thereby prepared for the refinement and purification of the spirit beings ("geistige Wesen") contained in them, and for their better and easier separation and purification. A large variety of vessels, usually constructed after some symbolic prototype, was used for this purpose. The simple Circulatoria were ordinary glass flasks, retorts the tubes of which were bent in a variety of ways, also so-called urine glasses used by physicians for diagnosis.
The operations performed in the pelican (fig. 16) and double or twin Circulatoria1) (fig. 17) provided with reflux tubes were considered as the most perfect kinds of circulation, especially for refining the "spirits."
Still more peculiar than the form of the Circulatoria was the source of heat used for the purpose of circulation, which was usually accompanied by fermentation, and even decomposition processes. Not only was the water bath (balneum Mariae) (fig. 18) and the ash bath (balneum per cinerem) (fig. 19) employed, but also the sun bath (destillatio solis) (fig. 20). The circulation vessels were also immersed in fermenting dough, and heated with this in an oven (destillatio pan is); or they were imbedded in decomposing, well wetted horse manure which was placed in a layer above unslaked lime in pits (destillatio per ventrem equinum) (fig. 21).
With the introduction of aromatic waters as one of the principal forms of medication, the condensation of the vapors gave rise to difficulties, because a greater degree of heat was necessary for their distillation. Plant material lying on the bottom of the still was also easily burnt, and the distillate received therefrom an empyreumatic odor and taste. With a strong heat a serious overheating of the helm and tube, which were usually constructed of lead or tin, took place, while with the employment of a moderate heat the yield of the distillate remained unsatisfactory. In order to overcome these disadvantages, and to prevent the flowing back of the distillate condensed in the helmet, as well as to increase the cooling effect of the air, the helmet known as the "Rosenhut" (fig. 1, p. 40 and fig. 22) was constructed as early as the 15. century. Near its base, at about the height of the outlet tube, a groove extended around the inside of the helmet. Through this the water, condensing on the upper inner wall of the helmet and running down, was conducted into the outlet tube and from there into the receiver. The "Rosenhut" was therefore in itself an inefficient air condenser, which served its purpose with much less efficiency than did the "Mohrenkopf" in the distillation of alcohol (fig. 15, p. 208).
1) duota est vas circulatorium a duabus auribus, vel viro utrumque brachium lateribus application habente, dictum, hujus inferior pars est in modum cucurbitae, cui impositus est alembicus in summo canalem habens; in loco autem conneviente duobus rostris incurnatus et in cucurbitam a capitello humorem, condensatum ducentibus praeditum.
In the preparation of the distilled waters, the first step toward a better condensation with cold water, consisted in surrounding the head of the helmet (alembic) with an oxbladder.
It was securely fastened and provided with a wooden stop-cock. The hood-like basin thus formed (fig. 23) was kept cold by means of flowing water. In a similar manner the helmet was also surrounded by a basin-like metallic addition which was either fastened by luting or soldering. Thus the helmet could be well cooled by running water (fig. 24). By means of an inner horizontal groove like that in the "Rosenhut" (fig. 22) the distillate which condensed on the inner walls of the helmet was conducted into the receiver.