since apparently the exemplar of the University of Virginia ( https://books.google.be/books?id=XN4NAAAAYAAJ ) is not downloadable even from the USA (what I hoped, because from here it is only poorly searchable), I finally found the needed volume... on the DLI again and under the title

"louis de law valle poussin memorial volume" (sic, a mix of Narendra Nath LAW/LA Vallée Poussin?)

(the front-cover, if there was one, is apparently missing)

I attach the table of contents (the whole volume deserves to be uploaded to Archives.org ; sorry for being myself unable to do that and make combined .pdf with the DLI stuff)

Thank you to all who kindly have tried to help,

Best wishes,

Christophe