What Painting Is: How to Think about Oil Painting ... - Victoria Vesna

122 WHAT PAINTING IS
species of vapors as they rise from the boiling sample. All that is
required to make a sharp, evilsmelling moonshine from table
wine is a distilling vessel, a cooling tube, and a collection vessel
(Figure 3). The main vessel, called an alembic, has a swollen belly
—the matrass or cucurbit—and a rounded condensing head,
leading to the “snake” and eventually the collection vessel. In
this case, the tube is curved and it passes through a barrel of cold
water, but those are unnecessary elaborations. (In modern
chemistry the barrel would be called a “cold-water jacket.”)
Artists can make their own turpentine by distilling it from pine
pitch, leaving a residuum called colophony. 4 In modern
chemistry, fractional distillation is the name of a method for
extracting several volatile substances from one sample by
arranging tubes and collecting vessels at different heights above
the sample, as in Figure 4. When crude oil is boiled in a covered
flask, the first substances to evaporate are benzene, gasoline,
kerosene, and naphtha; as the temperature rises, progressively
heavier oils will evaporate until there is nothing left in the flask
except the buttery petroleum derivatives such as vaseline and
paraffin. It is possible to catch different volatile oils in different
collection vessels by arranging them at various heights above the
crude oil. The higher the collection vessel, the hotter the
substance that will be caught, so that a single heating of a sample
of oil might yield a half-dozen different substances. If a plant is
boiled to extract its oils, the first to evaporate are the essential oils
that smell the same as the plant itself; they appear even before
the water has come to a boil. Later, as the water is boiling
furiously the fatty oils will appear in the collection vessel. They
are often odorless: when it is first extracted linseed oil has no
odor. After the water has nearly boiled away and the plants are
reduced to a mush, the still will extract the empyreumatic oils,
which are heavier and smell burnt. The heaviest oils will remain
in the alembic. 5 Oil of Dippel is the name for the especially
viscous oil that remains after repeated attempts to putrefy,
dissolve, and distill animal parts.
The alchemists understood some of that, but they also confused
fractional distillation with an illogical kind of distillation where
tubes and collection vessels all separate from a common point
like the spokes of a wheel. According to modern theory, the same
substances would have to be collected in each. Alchemists also
mixed the scientific and unscientific methods in all sorts of