The following external link does not, in my opinion, provide sufficient added value as to meet the criteria presented in the Wikipedia:External links guidelines page.
"They showed that the wavelength of this ultraviolet light corresponded exactly to the 4.9 eV of energy that the flying electron had lost; for visible light, different wavelengths correspond to different colours." (What is the purpose of the clause after the semicolon?)
'In his Nobel lecture, Franck admitted that it was "completely incomprehensible that we had failed to recognise the fundamental significance of Bohr’s theory, so much so, that we never even mentioned it once in the relevant paper."' (Confusing. Which "relevant paper"? They must be referring to their 1914 paper, since the 1918 paper fully acknowledged Bohr.)
"In supervising doctoral students, Franck had to ensure that their thesis topics were well-defined, that they would teach the candidate how to conduct research, and while staying within the limits of their ability, their equipment and their budget, that they would contribute original science." (Seems a bit run-on.)
Y Changed to: "In supervising doctoral candidates, Franck had to ensure that thesis topics were well-defined, and would teach the candidate how to conduct original research, while still staying within the limits of the candidate's ability, the laboratory's equipment and the institute's budget." Hawkeye7 (talk) 21:42, 10 August 2015 (UTC)[reply]