Chemical Engineering April 2023 - 27

Chem Chronicles
" Pott Ash Maker " : The U.S.' First Patent Holder
By David Cole, Science History Institute
R
obert Fulton, Eli Whitney,
Thomas
Edison, Henry
Ford - these are some of
the larger-than-life figures
who spring to mind when reflecting
on the history of innovation and invention
in the U.S. But the first person
in American history to secure
a U.S. government patent for an
invention is not a household name.
That distinction lies with Samuel
Hopkins, a Quaker tradesman of no
particular distinction who, in middle
age, and at the dawn of the American
republic, launched a second
career as an innovator, entrepreneur
and self-described " chemist. "
Hopkins' second career was built
on his interest in what his contemporary,
the American promoter and
pamphleteer Tench Coxe, referred to
as " a form of alchemy " - an effort
that promised to be a catalyst for the
early U.S. industrial economy.
Born in Maryland in 1743 (a first
cousin, once removed, of the Johns
Hopkins who founded the eponymous
university), Samuel Hopkins
identified as a " merchant " in Philadelphia
until the census of 1790, when
his vocation was recorded as " Pott
Ash Maker. " This change in professional
identity
was occasioned by
Hopkins' timely response to the recent
creation of an institution that
would help transform
his
young
country into a nation of inventors: the
U.S. patent system. Anticipated in Article
I of the U.S. Constitution, the first
federal patent statute was passed by
Congress in April 1790, authorizing
the government to grant letters patents
for a fourteen-year period for the
invention of " any useful art, manufacture,
engine, machine or device, or
any improvement therein not before
known or used " that could be established
as " useful and important. "
In 1836, a fire at the U.S. Patent
Office destroyed the records of many
patents sought and granted from
1790 until that date, but the one
granted to Hopkins survived. Now
in the holdings of the Chicago Historical
Society, this document (Figure
1) was signed by President George
Washington and by then-Secretary
of State Thomas Jefferson (who, in
that capacity, was initially charged
with superintending the Patent Office
and examining patent applications).
The document certifies Hopkins'
patent for " An Improvement ... in the
making of Pot-ash and Pearl-ash by
a new Apparatus and Process. "
'Principal industrial chemical'
Potash (potassium carbonate) has
been described
by
the
historian
William L. Roberts as " the principal
industrial chemical of the 18th century. "
Through variations on a simple
process familiar to American farmers
of the period, timber that was not
suitable for fuel or building material
was burned in large cauldrons or
" pots " (hence the name, " pot-ash, "
often hyphenated during this
era).
The resulting ashes were blended
with water and heated, producing
a residual black substance. Further
heating to remove additional impurities
yielded " pearl ash, " a more
refined product. Drawing on large
quantities of timber harvested from
the northern U.S., numerous independent
producers of pot and pearl
ash addressed burgeoning demand
for these products in the manufacture
of soaps, glass, fabric dyes,
saltpeter and detergents, among
others. Potash was also a significant
American export good in the 18th
and 19th centuries, and its value in
domestic and foreign markets, coupled
with the low costs and barriers
to entry in its production, induced
many American farmers and tradesmen
to supplement their primary incomes
with potash asheries.
Into this " potash boom " stepped
Hopkins, whose patent claims rested
on a key improvement to the
traditional potash-making process
- " burning the raw ashes previous
to their being dissolved and boiled in
water. " Furnaces built according to
Hopkins's patent specifications purportedly
would generate 50% more
pearl ash from a given yield of raw
ash than would common methods
of leaching and boiling the residual
CHEMICAL ENGINEERING WWW.CHEMENGONLINE.COM
APRIL 2023
Smithsonian
FIGURE 1. The first patent issued in the U.S. was
for a new process for making and refining potash
" black leys. "
On the heels of securing his patent,
Hopkins produced a pamphlet
extolling the technical virtues and
profit-making potential of his method,
with the aim of licensing the technology
to the thousands of potash/pearl
ash producers already operating in
the U.S. and Canada. He obtained
testimonials to the superiority of his
method from leading scientific figures
of federal-period Philadelphia, including
Caspar Wistar and Benjamin
Rush, whom he described as " well
acquainted with chemistry. "
Traveling across the northern U.S.,
Hopkins pursued collaborative ventures
with large landowners (such as
the speculator Robert Morris), who
sought to generate income from newly
acquired, timber-rich holdings. Charging
hefty licensing fees, and constructing
his potash works for as much as
$200 per works, Hopkins banked on
the assumption that substantially increased
yields of high-end pearl ash
would justify the large initial capital expenditures
that licensees would need
to invest in his technology.
Sadly for Hopkins, most potential
customers remained wedded to less
efficient, but less capital-intensive,
traditional production methods. In the
years before his death (most likely in
1818), Hopkins left Philadelphia as an
entrepreneurial failure, reliant on his
children in New Jersey for material
support. But while Hopkins' invention
was not a financial success, he
forged a legacy as the first American
- and first chemist - to obtain a
patent. The " Pott Ash Maker's " place
in inventing history is secure.
n
Editor's note: This column was authored by David Cole, president
and CEO of the Science History Institute (Philadelphia, Pa.; www.
sciencehistory.org).
27
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Chemical Engineering April 2023

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