A Russian reader:
Mr. Derbyshire — You should be advised that Derbysh is actually an old Cossack name. According to this web page (which is in Russian) there was someone named Derbysh in a Cossack census of 1632. The author thinks that the man got his name as an adult, and that the name itself most likely derives from a verb or verbs with the following three meanings: (1) to look for easy money, (2) to hit someone, or (3) to get drunk.
[Me] That is obviously a lineage completely unrelated to the English Derbyshires. We hardly ever hit people.
A different reader offers this:
Mr. Derbyshire — No discussion of Russian names is complete without referencing the Gershwin/Weill masterpiece “Tschaikovsky.” Made famous by Danny Kaye in the musical “Lady in the Dark,” the song goes through a tongue-twisting high-speed list of Russian composers. While there is a shameful paucity of good performances of the song on YouTube, the Amazon page for the recent British revival cast recording has a nice long selection from the song here.
[Me] Thank you, Sir. For this fifties kid, Danny Kaye will for ever be the court jester.