Ira Rensen (ca. 1846-1927) founded the Department
of Chemistry at John Hopkins University and initiated the first
center
for chemical research in this country. Rensen was reading a textbook
on chemistry where the statement said "nitric acid acts upon copper".
He was working in a doctor's office at the time and determined to see
what
"acts on" meant. He sacrificed a copper penny and poured some nitric
acid on the penny on a table. "But what was this wonderful thing
which I beheld? The cent was already changed, and it was no small
change
either. A greenish blue liquid foamed and fumed over the cent and
over the table. The air in the neighborhood of the performance became
dark red. A great colored cloud arose. This was disagreeable
and suffocating--how should I stop this? I tried to get rid of the
objectionable mess by picking it up and throwing it out of the window,
which I had meanwhile opened. I learned another fact--nitric acid
not only acts upon copper but it acts upon my fingers. The pain led
to another unpremeditated experiment. I drew my fingers across my
trousers and another fact was discovered. Nitric acid also acts upon
trousers. Taking everything into consideration, that was the most
impressive experiment, and, relatively, probably the most expensive
experiment
I ever performed. I tell of it even now with interest. It was
a revelation to me. It resulted in a desire on my part to learn more
about that remarkable kind of action. Plainly the only way to learn
about it was to see its results, to experiment, to work in a
laboratory."