Paneth, Fritz

What I hope to have added to the discussion has been a philosophical reflection on the nature of the concept of element and in particular an emphasis on elements in the sense of basic substances rather than just simple substances. The view of elements as basic substances, is one with a long history. The term is due to Fritz Paneth, the prominent twentieth century radio-chemist. This sense of the term element refers to the underlying reality that supports element-hood or is prior to the more familiar sense of an element as a simple substance. Elements as basic substances are said to have no properties as such although they act as the bearers of properties. I suppose one can think of it as a substratum for the elements. Moreover, as Paneth and before him Mendeleev among others stressed, it is elements as basic substances rather than as simple substances that are summarized by the periodic table of the elements. This notion can easily be appreciated when it is realized that carbon, for example, occurs in three main allotropes of diamond, graphite and buckminsterfullenes. But the element carbon, which takes its place in the periodic system, is none of these three simple substances but the more abstract concept of carbon as a basic substance. 

A stream of tetramethyllead vapor, (CH3)4Pb, was passed through a quartz tube which was heated at one spot a mirror of metallic lead was deposited at the hot point, and the gas escaping from the tube was found to be chiefly ethane. The tube was next heated upstream of the lead mirror while more tetramethyllead was passed through a new mirror appeared at the hot point, the old mirror disappeared, and the gas escaping from the tube was now found to be chiefly tetramethyllead. Experiments like this, done by Fritz Paneth at the University of Berlin, were considered the first good evidence for the existence of short-lived free radicals like methyl, (a) Show how these experimental results can be accounted for in terms of intermediate free radicals, (b) The farther upstream the tube was heated, the more slowly the old mirror disappeared. Account for this. 

I will draw liberally on the work of my thesis grandfather, the chemist, Fritz Paneth. I use the term somewhat unusually, because Paneth was not the person who advised my own advisor Heinz Post but was, in fact, his natural father, from whom Heinz presumably developed an interest in the philosophical aspects of science. I will touch on such areas as realism, including naive realism, the nature of the periodic system, metaphysical aspects of chemistry, and, as suggested by the editors, the reduction of chemistry. 

Post founded the department of history and philosophy of science at what was then Chelsea College, London University, and which subsequently merged with King s College, London. He has also been one of the most influential postwar philosophers of science in Great Britain. His father, Fritz Paneth, one of the founders of radiochemistry, had a deep interest in philosophical aspects of chemistry, as can be seen in his collected essays (Paneth, 1965). 

The discovery of the simpler but more reactive methyl radical dates back to experiments by Fritz Paneth in the late 1920s showing reversible thermal decom-... 

Nevertheless, Dingle who founded the British Journal for the Philosophy of Science was sufficiently interested in chemistry to act as the co-editor of the philosophical essays by the chemist Fritz Paneth (Dingle and Martin 1964). 

Following a brief period with Haber, Georg Hevesy began work with Rutherford at Manchester in 1910. In 1913, he began work with Fritz Paneth in Vienna and conducted the first radiotracer experiments. At that time, it was known that one of the products of radium decay was a substance, having its own unique decay signature, called radium-D. Hevesy tried unsuccessfully to separate radium-D from lead. In 1913, Alexander Fleck (1889-1968), working with Soddy, found that radium-D, radium-B, thorium-B, and actinium-B were chemically inseparable from lead and were, therefore, isotopes of lead. 

In the Berichte der Deutschen Chemisches Gesellshaft for 1926 (59B, 2039), the eminent radiochemist Fritz Paneth and K. Peters published a paper entitled "On the Transmutation (Verwandlung) of Hydrogen Into Helium." Paneth had developed a method for the measurement of very small quantities of helium. In this paper, he reported that 1 g... 

In light of this fact, finding explicit bivalence in the official definition of chemical element, at the very heart of chemistiy, seems odd. The historical and disciplinary reasons behind it have been the topic of several articles in the philosophy of chemistry arena. ° The definition originated with Fritz Paneth in 1931, in association with his successful work on the stams of isotopes, which had been a vexing problem of early twentieth century chemistry. 

When Fritz Paneth s group in 1953 tried to determine meteorite ages by the He/U method (Paneth et al. 1953), they found much larger amounts of helium than could be accounted for by uranium decay and thus stumbled on the discovery of cosmic-ray-induced nuclear reactions in meteorites that subsequently became the subject of extensive research. Many radionuclides with half-lives ranging from days to millions of years as well as some stable spallation products have been identified in meteorites. From the amounts found, the exposure ages of meteorites in space and the average cosmic-ray flux and its time variation can be deduced (see, e.g., Schaeffer 1968). 

Some authors believe that the interpretation of the properties of the elements passed from chemistry to physics as a result of the discovery of radioactivity. They speak of the redefinition of Mendeleev s chemical element, which would lead to its appropriation by physics. 1 believe this view to be overly reductionistic, as presumably did Fritz Paneth, who formulated his intermediate position in order to uphold the integrity of the chemical view of the elements and of the periodic system. ... 

In using the word metaphysical, 1 am following the work of Fritz Paneth on this question. Some contemporary philosophers of chemistry, e.g., Paul Needham and Robin Hendry, deny any metaphysical notion when discussing the question of basic substances. 

The next major resuscitation of Mendeleev s real elements took place at a rather crucial historical juncture at which the rapid discovery of isotopes threatened to render the chemist s periodic table redundant. Some chemists pointed out that the number of elements seemed to have grown out of all proportion and that it would necessitate moving to a table of isotopes. But as Austrian born Fritz Paneth recognized, this would have represented putting all emphasis on the elements as simple substances that could actually be isolated or, in other words, on the isotopes. If attention were placed on unobservable elements, in the manner recommended by Mendeleev, the chemist s periodic table could be salvaged. The only change required was to characterize these real elements by their atomic number rather than by their atomic weights as Mendeleev had done. 

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