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The E-Sylum:  Volume 9, Number 31, July 30, 2006, Article 16

CYANIDE, CANARIES, AND THE BUREAU OF ENGAVING AND PRINTING

Mark Tomasko writes: "Thanks for the great work you do on The E-Sylum.
I enjoyed the piece about Chris Madden. He was also profiled in the Ohio
State University Alumni Magazine, May-June 2006 issue. Chris is an
excellent engraver, and while the article does not mention it, he did
the Treasury building on the back of the $10 bill. He, Will Fleishell
and Ken Kipperman are the last people employed as bank note picture
engravers in the United States (all at the BEP in DC), to my knowledge.
Another talented engraver who did picture work, Richard Baratz, is now
at the BEP in Texas, though not doing picture work.

As to the cyanide question, potassium cyanide was used to harden steel
once it had been engraved, so that it could be transferred (i.e., die to
transfer roll and transfer roll to document plate). I strongly suspect
that is the use of cyanide referred to. While I have not heard the
canary story, it probably makes sense that there was some crude
mechanism for determining if the fumes got to dangerous levels."

A knowledgeable E-Sylum reader writes: "One of the problems faced by
people who work with engraved steel plates is oxidation, and ultimately
rust.  This was particularly true during humid summers before the advent
of modern HVAC equipment.  Washington, DC occasionally boasts humidity
levels of the sort experienced in equatorial latitudes.  I suspect
that engravers had to protect their work with light oil, cosmoline,
or wax to prevent oxidation.

After an engraving is approved for use on currency, it is transferred
to a working plate.  This occurs in several steps.  The engraving is
transferred to a 'roll', then the 'roll' is transferred to the
working plate.  The working plate also receives impressions from
other rolls that transfer other currency elements such as counters,
lettering, etc.  Additional transfer processes occur when a finished
currency die must be replicated in order to print multiple pieces of
currency in one operation.  US Currency has been printed with plates
containing as few as 1 or 2 subjects, and as many as 32 subjects.

I believe the procedure of transferring engravings to create working
currency plates is known as 'siderography'.  This process is similar
to coin die production from master dies and hubs.  The main difference
between currency plates and coin dies is that coin dies only contain
one coin obverse or reverse whereas currency plates have as many as 32
faces or backs on each plate.

So where does cyanide enter the picture?  Whenever a steel engraving
is transferred, the receiving steel must be heated first.  After the
design is transferred, the receiving roll or plate must be hardened
by being rapidly cooled.  Hot steel is particularly vulnerable to
oxidation.  The chemical bath used to harden the steel must not allow
oxidation to occur.  In the past, the only liquid deemed appropriate
for this process was potassium cyanide.  This procedure was usually
performed in a well ventilated area.  Even in pre-OSHA days, the
deleterious effects of potassium cyanide fumes were well known.

As you may know, American Numismatic Rarities is having a sale in
Denver next month that contains some currency production materials
from the American Bank Note Company.

Example of what I referred to as a 'roll', ANR calls a 'cylinder die':
cylinder die

Example of a finished 3 subject currency plate:
3 subject currency plate

[QUICK QUIZ: Who can name another numismatically-related
use of cyanide? -Editor]

Bob Leuver, former head of the U.S. Bureau of Engraving and
Printing and Executive Director of the American Numismatic
Association writes:

"The canaries were "employed" by the BEP in 1979, the year--and
just before--I arrived at the Bureau.  There were some interesting
and humorous aspects to the fire department's response and the death
of a canary while in Federal service."

[Bob hopes to write a more detailed article on the topic for the
Numismatist magazine, but sent us the following digest in the
meantime. -Editor]

  Wayne Homren, Editor

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