e. In the filtration field, the
following attained considerable distinction: Harvey Ricker's Half-Minute
pot, employing a cotton sack with re-inforced bottom, introduced about
1881; the Kin-Hee pot of 1900; Cauchois' Private Estate coffee maker,
using Japanese filter paper, introduced in 1905; Finley Acker's
percolator, introduced the same year, which also employed a filter paper
between two cylinders having side perforations; the Tricolator, 1908;
King's percolator, using filter paper, in 1912; and the "Make-Right",
1911, with its adaptation as presented in the Tru-Bru pot of 1920.

[Illustration: THE TRICOLATOR IN OPERATION]

The Make-Right was the invention of Edward Aborn, New York, and
comprised two telescoping open wire frames, or baskets, with a flat
piece of muslin between them. In the Tru-Bru pot, the same idea was
employed, except that the wire frames were so constructed as to furnish
four drip points to afford better distribution on the ground coffee and
to lessen the time of filtration. There was also a porcelain top, to
house and to raise the filtration device, above the brew with an opening
through which the boiling water could be poured without exposing the
ground coffee.

[Illustration: KING PERCOLATOR, AS APPLIED TO A HOTEL OR RESTAURANT URN]

Among later developments of the genuine percolator principle that have
attracted attention in this country, mention should be made of the
Phylax coffee maker, and the Galt pot.

In 1914-16, there was a revival of interest in the United States in the
double glass-globe method of making coffee, introduced into France as
"double glass balloons" in the first half of the nineteenth century.
American ingenuity produced several clever adaptations, and several
notable filter improvements. Advertising developed a great demand for
glass percolators, as they were first called; but although five attained
considerable prominence, only two survived and, at this writing, are
still being manufactured. Both are double glass-globe filters employing
a spirit lamp, gas, or electricity as heating agents.

[Illustration: THREE TYPES OF AMERICAN COFFEE MAKERS IN OPERATION

Left, Blanke's Cloth Filter--Center, Phylax--Right, Galt Vacuum device]

Within the last few years, it has become the fashion to obtain patents
in the United States on "the art of brewing coffee", or the "art of
making coffee". Instances are the patents issued to Messrs. Calkin and
Muller. In the Calkin patent