J J Thomson, nobel prize-winner and widely credited with discovering the electron, caused a degree of consternation in Cambridge in 1884 when he was appointed to succeed Lord Rayleigh as Professor of Experimental Physics at the Cavendish Laboratory in Cambridge. Thomson was only 28 and known more as a theoretical than an experimental physicist; he was not the obvious candidate.
I have recently found evidence showing that before putting himself forward, Thomson actually spearheaded a campaign to attract another candidate to the post. This candidate was Sir William Thomson (no relation to J J), the most eminent physicist of the day. Sir William had been asked to fill this post twice before and had refused each time: once when the Laboratory was founded in 1871 ( Clerk Maxwell was appointed instead), and again in 1879 on Maxwell’s death.
The Cambridge University Registry Guard Book for physics (a sort of scrapbook archive of documents relating to the physics laboratory) contains a copy of a memorial addressed to Sir William, urging him to take the chair. The campaign was led by J J and all members of the university who supported it were urged to contact him.
The case may have seemed hopeless, and J J had, so far, managed significantly fewer signatures on his memorial (24) than the equivalent petition to Lord Rayleigh five years earlier in 1879 (around 100) . But it is interesting in showing that J J was already asserting his leadership within the Cambridge physics community – and raising his profile in this way clearly did him no harm when he came to apply for the post himself.
 Cambridge University Library, University Registry Guard Book, CUR 39.33, item 66
 Cambridge University Library, University Registry Guard Book, CUR 39.33, item 56