Alembic apparatus

By the thirteenth century AD, essential oils were being produced along with medicinal and herbal preparations in pharmacies. Around this time improvements in distillation techniques were made, in particular the development of the alembic apparatus, which would eventually estabUsh the quaUty of such matenals. As a result, many of the essential oils in use today are denved from those produced in the sixteenth and seventeenth centunes in terms of odor character, even though production methods have continued to evolve. The current practice of aroma therapy is an indication of this common root of medicinal and fragrance chemistry. 

Egyptians purportedly practiced distillation around 1000—2000 BC by heating wine and making a product called arden spidts. China and India are also said to have carried out distillation in the pre-Christian era. The Chinese reportedly made a distilled beverage from nee beer around 800 BC. The Arabs learned about distillation from the Egyptians and developed an apparatus in the form of a closed heated container that was called an alembic. 

Fig. X. p. 85, represents methods of distilling with an apparatus for cooling the volatile products the lower vessel is an alembic, with a long neck, the upper part of which passes through a vessel containing cold water.

There are many different forms of vessel described and depicted in the alchemical literature and emblematic engravings. There are a seeming multiplicity of forms of retort, pelicans, water baths, alembics, cucurbites, stills, etc. However, in the interior work we will find that all these different outer manifestations of the apparatus reduce to three archetypal forms - which we can call the CRUCIBLE, the RETORT and the STILL. 

M Now place the curcurbite to the West of the Altar, holding the Lotus wand by the black end, perform a magical invocation of the Moon in her decrease and of Cauda Draconis. The curcurbite is then to be exposed to the moonlight (she being in her decrease) for nine consecutive nights, commencing at full moon. The Alembic Head is then to be fitted on. (The flask is reattached to the rest of the apparatus.)... 

The Arabs were the perfecters if not the inventors of the art of distillation, in which a liquid is converted into a vapor by boiling, and then condensed back into a liquid by cooling. The aim of distillation is purification. The alchemists developed different vessels for the distillation process. The lower part of a still, the apparatus used for distillation, is called a cucurbit the liquid is heated in this container. The upper part, where the heated vapor condenses again, is the alembic. The receiver for the distilled liquid is the aludel... 

In other districts where the wines have a strong, earthy flavor somewhat more elaborate apparatus is used. The La Rochelle district uses the Alembic des lies which is a pot still with rectifying equipment. The Midi uses a continuous distilling column of the kind in favor in this country, excepting that it is equipped with a faucet or tap at each plate. This arrangement enables the operator to distil at higher or lower strengths at will. 

The distillation apparatus in Figure 72(a) places the alembic head on top of a wide-mouth flask (a kind of cucurbit, a more squat version of a matrass) This apparatus would be more useful for a less volatile liquid Figure 72(b) is a one-piece pelican. Note how the bird s neck forms a curved arm as it bites its chest When... 

The apparatus in Figure 119b has a built-in efficiency of two collection vessels. This double alembic or distilling head can be made of iron if vegetables are distilled or steam-distilled. However, the distillation of oil of vitriol and other acidic substances (Figure 120) requires tin or tin-lined vessels. Distillation of mercury, Le Fevre notes, can never employ metallic vessels since amalgamation will occur. The diarist Samuel Pepys visited Le Fevre s laboratory on January 15,... 

FIGURE 119. A nice shelf of mid Seventeenth-cenmry glassware and an efficient-looking double alembic (still head) that allows the entire apparatus to be lifted off of the furnace when such control is desired (from Le Fevre s A Compendious Body of Chymistry). 

There are probably more types and styles of distillation apparatus than exist for any other technique in chemistry. Over the centuries, chemists have devised just about every conceivable design. The earliest known types of distillation apparatus were the alembic and the retort (Figure 14.1). They were used by alchemists in the Middle Ages and the Renaissance and probably even earlier by Arabic chemists. Most other distillation equipment has evolved as variations on these designs. 

Other laboratory operations performed by the Alexandrian alchemists included solution, filtration, crystallisation, sublimation, and distillation. The art of distillation shows a steady improvement over the years. In the earliest form of distillation apparatus, the vapours ascending fi om the flask or bikos were condensed in the hood or ambix, and then ran down the spout into the receiver (Figure 2.4). The Arabs later used the name alembic for the condensing hood. This method of condensation was inefficient, and it was not until much later that water-cooled condensers were introduced. The alchemists employed several different kinds of furnace, and also introduced the sand bath and water bath for heating purposes. The water bath is reputed to have been invented by one of Zosimos s predecessors called Maria the Prophetess or Maria the Jewess. Today, when a pan of hot water is used to heat another vessel in the kitchen, the contrivance is still called a bain -Marie. 

Figure 3.3 Chemical apparatus illustrated in Lemery s Cours de Chymie of 1675. The distillation apparatus at the bottom right is equipped with a Moor s head. This surrounds the alembic (still head) and is filled with cold water to bring about more efficient condensation...

Jabir ibn Hayyan (Geber), a Persian, 800 AD, who was the first to use alembics and retorts or multiple chemical apparatus. An alembic (feed flask) and retort (accumulator) are glassware vessels the apparatus has a long tapering neck that slopes downward. The distance between the alembic and the retort acts as a type of air-cooled condenser. 

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