At the start of 1830, the Pushkin-Delvig camp began a new periodical, «Литературная газета» [The Literary Gazette], to counteract the malign influence of Bulgarin and Grech (the editors of the reactionary Northern Bee); Delvig was editor-in-chief, with Orest Somov as the main critic and assistant. It was not expected to last long (such ventures have always tended to be ephemeral), and in fact was shut down after a year and a half; on April 26 Vyazemsky wrote to Pushkin: “Дельвиг — ленив и ничего не пишет, а выезжает только sur sa bête de somme ou de Somoff” [Delvig is lazy and writes nothing, and he relies exclusively sur sa bête de somme ou de Somoff]. That little pun makes use of the French idiom bête de somme ‘beast of burden,’ which is an interesting relic.
In French, un somme is a nap and une somme is a sum, but this is neither; it’s used only in this phrase, which goes back to the 12th century, and it’s from Late Latin sauma/salma/soma ‘packsaddle,’ derived from Latin sagma, a straight borrowing of Greek σάγμα. It’s allegedly a feminine noun, but how can you tell when it’s only used in this phrase? My question to French speakers is: do you have any sense of this somme as a word in its own right, or is it just an unanalyzable (and presumably mysterious) part of the phrase bête de somme?