Letter of 2. November 1928 from Hermann Mark to Hermann Staudinger
I was sorry to read in your letter that you feel your priority has been violated by the statements made by Professor Meyer. I am convinced that nothing was further from Professor Meyer’s mind than this and I myself have also tried especially hard to emphasise the importance of your fine work appropriately, not only in our work but also and in particular in my lecture in Hamburg.
I do, however, consider it sensible to introduce the word ‘primary valence chain’, because it refers to structures that are not completely identical to what has been called a molecule up to now. I always associate the word ‘molecule’ with the concept of a large number of completely identical structures, whereas the term primary valence chain is specifically supposed to include the fact that the same substance contains structures that are very similar to each other, cannot be separated from each other by chemical methods but differ from one another a little in their size, so that while it is not possible to indicate a precise molecular weight, an average primary valence chain length can be quoted. If this fact is specifically added to your macromolecule, then the two terms are, as far as I can see, identical and it is a question of convenience whether one says ‘primary valence chains’ or ‘macromolecules of fluctuating size’.
For this reason, I would not want to stress this difference too much; I think that it is much more expedient and much more appropriate to the situation if we agree that we essentially think the same, i.e. that the chemical primary valences play a crucial role in the structure of high-polymer substances. I consider it less important that we give different names to the intermediate factors. The main issue in the near future will, after all, be whether the positions held by you and us as well as Freudenberg, Willstätter and others prevail or whether the people will be proved right who think that it is necessary to assume new kinds of association forces not yet detected in chemistry up to now in order to explain everything that we have experienced. I think that we should proceed together in commenting on this issue and should not emphasise certain differences between our personal views that are in my opinion minor; if we did, the high-polymer community could easily make the mistake that is only too familiar from politics; that a major issue was not given close enough attention and was not presented clearly enough because of minor differences between opinions that were not far apart.
I will try and find a way to come to Freiburg again as soon as possible, because I would like very much to talk to you in detail about this issue.
Until then I remain