rature of 40 deg. to 100 deg. F. The temperature
should seldom be allowed to rise above 150 deg. F. The pressure is then
allowed to escape and a partial vacuum created in the apparatus. This
alteration of pressure and vacuum is continued until the desired
maturation is obtained. Desvignes[111] employs a similar procedure,
although he accomplishes seasoning by treating the coffee also with
oxygen or ozone.[112] First the coffee is rendered porous by storage in
a hot chamber, which is then exhausted prior to admission of the oxygen.
The oxygen can be ozonized in the closed vessel while in contact with the
coffee. Complete aging in a few days is claimed.

Weitzmann[113] adopts a novel operation, by exposing bags of raw coffee
to the action of a powerful magnetic field, obtained with two adjustable
electro-magnets. The claim that a maturation naturally produced in
several years is thus obtained in 1/2 to 2 hours is open to considerable
doubt. A process that is probably attended with more commercial success
is that of Gram[114] in which the coffee is treated with gaseous
nitrogen dioxid.

By far the most notable progress in this field, both scientifically and
commercially, has been made by Robison[115] with his "culturing" method.
Here the green coffee is washed with water, and then inoculated with
selected strains of micro-organisms, such as _Ochraeceus_ or
_Aspergillus Wintii_. Incubation is then conducted for 6 to 7 days at
90 deg. F. and 85 percent relative humidity. Subsequent to this incubation,
the coffee is stored in bins for about ten days; after which it is
tumbled and scoured. With this process it is possible to improve the
cupping qualities of a coffee to a surprising degree.

_Renovating Damaged Coffees_

Sophistication has often been resorted to in order ostensibly to improve
damaged or cheap coffee. Glazing, coloring, and polishing of the green
beans was openly and covertly practised until restricted by law. The
steps employed did not actually improve the coffee by any means, but
merely put it into condition for more ready sale. An apparently sincere
endeavor to renovate damaged coffee was made by Evans[116] when he
treated it with an aqueous solution of sulphuric acid having a density
of 10.5 deg. Baume. After agitation in this solution, the beans were washed
free from acid and dried. In this manner discolorations and impurities
were removed and the beans given a fuller appearance.

The addition of glu