I have been reading A Tale of Seven Elements by Eric Scerri. The book discusses the discovery of
the remaining seven elements “lighter” than uranium in the Periodic Table
following Henry Moseley’s key finding in 1913 that the elements should be
ordered according to atomic number rather than mass. Coincidentally, we
discussed key experiments on the structure of the atom, atomic numbers, mass
numbers and isotopes in my General Chemistry class on Monday morning.
The seven elements in the order they were discovered between
1917 and 1945 are protactinium (#91), hafnium (#84), rhenium (#100), technetium
(#43), francium (#87), astatine (#85) and promethium (#61). The spirit of
nationalism in between two world wars contributed to some of the rivalry and
bitter disputes over these discoveries. Scientists can be rather passionate when
it comes to intellectual property. Summarizing the work of sociologist Robert
Merton, Scerri writes: “[In discussing] scientific knowledge as a form of
property… the protagonists in a [commercial] dispute can often resolve their
differences because there is money to made from the property in question. But
in academic life a discovery leads to intellectual property, which is seldom
commercially exploitable [at least prior to Merton’s writing in 1957]. As a
result, the only thing that the
scientist can benefit from… is the fame from having discovered the knowledge.
Small wonder then that scientists will fight so ferociously to retain the only
benefits that might come from their hard-won intellectual property.”
In the book’s introduction, Scerri puts this issue of
priority disputes front and center of his book in a section titled “The Nature
of Science and Priority Disputes”. Here is an excerpt from the first few
paragraphs that convey the gist:
“Whereas theories and concepts that appear in textbooks are
presented as being fully formed, real science is in a constant state of flux.
When science is reported in the press, one seldom hears of the errors that led
up to a discovery. In fact, actual science is full of mistakes and wrong turns…
The best we can hope for is an approach to the truth, perhaps in an incremental
fashion, meaning that current science is necessarily incorrect. To better
understand science is to face up to the historical twists and turns and the
mistakes. Moreover, the practice of science often involves struggles between
individuals or teams of scientists trying to establish priority, not because
scientists are egotists, although some are, but because scientific society
rewards the winners who can boldly assert their claims.”
As he goes through each of the seven elements, Scerri pays
particular attention to the disputes of competing individuals and groups. What
it means to “discover” an element is not so straightforward. Is finding the
element in a compound sufficient? Or must it be isolated as the pure element?
If so, how much? Must the isotope be stable or relatively long-lived?
Interestingly, there was a time when “artificially” produced isotopes had lower
priority over “natural” discoveries, the latter often coming from the
painstaking grinding up of ores and subjecting them to chemical separation
techniques. While the synthesis of urea by Fredrich Wohler in 1873 is the archetypical
example blurring the demarcation of organic and non-organic chemistry, it was
only in 1947 when Fritz Paneth declared that the “chemist no longer [should]
discrimate between natural and artificial elements”. He also laid out the rules
for assigning names and symbols, as summarized by Scerri:
“(1) The right to name an element should go to the first to
give definitive proof of the existence of one of its isotopes. (2) In deciding
the priority of the discovery, there should be no discrimination between
naturally occurring and artificially produced isotopes. (3) If a claim to such
a discovery has been accepted in the past, but refuted in later research, the
name given should be deleted and replaced by one chosen by the real
discoverer.”
Scerri’s vignettes are interesting, but the narrative as a
whole feels like it could have used more editing. It is choppy in some areas
and repeats itself, sort of like my PhD thesis, which consisted of trying to
find prose to connect a bunch of papers I “pasted” together. Hopefully my writing
has improved since then. I enjoyed Scerri’s earlier book The Periodic Table: Its story and its significance. A Tale of Seven Elements is his
follow-up, but the earlier book is better written in my opinion. But the
stories move briskly and the writing feels aimed at a more general audience;
the earlier book was more dense and geared towards readers with some background
in history and philosophy of science.
While I had bits and pieces of knowledge about the discovery
of some of the seven elements, the book helped bring these different threads
together. I did not know much about hafnium (#72) so almost all of it was new
and interesting. The chapter on technetium (#43) included a vignette to the
“natural” Oklo reactor; this was really interesting as I was unaware of
it even though the discovery was back in 1972. In any case, if you’re
interested in the discovery stories of these seven elements and priority
disputes, Scerri’s book is a nice quick read.
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