Dr. Alfred's Partheil's Paper, Page 3

are the periodic functions of their atomic weights. This view permits to propose a system of elements, the so called natural or periodic system that - with the changes became necessary since, but mainly after Mendelejeff's proposal - can be formulated as shown on page 469.

In the periodic system families of related elements are clearly recognizable in vertical rows: The noble gases, the alkaline metals, the alkaline earth metals, the element group of nitrogen, the halogens and others appear as natural families. As already emphasized by Mendelejeff, the vertical rows illustrate further the relationships between oxidation number and atomic weights. The ability to combine with hydrogen or halogen rises from row I to row IV and then decreases again, while the ability to combine with oxygen from M2O in row I to M2OT in row VII rises. But one must not be blinded too much by this striking regularity. It is well known that many elements form oxides of which the most suitable ones have been chosen here.

Other properties that clearly show the periodicity are e.g. the specific weight and the atomic volume of the elements and their combinations, the melting points, the thermal expansion, the electric conductivity, the color of the ions, the diffusion velocity of the ions, and others.

The periodic system of the elements does not only give us the main outline of a natural classification of elements, it also allows us to determine the atomic weights of elements of which only the equivalent weight is known. It even allows to predict the properties of so far unknown elements. Based on the periodic system, Mendelejeff was able to predict the existence of an element he called eka-silicone. He also predicted atomic weight, specific weight, atomic volume and a whole row of other chemical and physical properties this element would have. When thirteen years later C.R. Winkler discovered germanium, it was found that this substance had all the properties predicted by Mendelejeff for eka-silicone. Also gallium and scandium have been predicted by the periodic system.

But still the meaning of the periodic system in the form it has today must not be overestimated. So can argon, tellurium and cobalt be put in their right place in the system only through an arbitrary change of position, while we must not forget that today our knowledge of the elements is still insufficient and one sided. That is because the chemical processes that happen in ordinary or slightly raised temperatures have been studied much more in depth than those that happen in high temperatures, and because we have a more extensive knowledge of the reactions that happen in a watery solution than in other solutions. The periodic system we deal with is not a natural law recognized in all details and consequences but merely the foundation on which such a natural law might one day be built.