Trill with accidental "on the line"
This trill is from an edition published by Oxford University Press in 1925. I have never seen this notation used, with the accidental positioned right on the trill line. Does anyone know what this notation means, in a violin part?
And how should it best be represented in a more conventional way?
I have read "How to create trills and ornaments with accidentals (and playback)" :
but it doesn't cover this specific case where the accidental is positioned on the trill line (neither above nor below).