A well drawn comparison. MES and Cendrars do not ignore convention so much as reveal its insufficiency.
Who Captain Lacroix was is beyond me - there's no obvious candidate, but on the other hand if the candidate was obvious, Cendrars would never have mentioned him. What a wonderful phrase that is - Language is a thing that perverted me. And what an interesting connection to The Fall. As for the Sonia Delaunay pochoir for the Prose of the Trans-Siberian - I have now seen 3 different copies, plus various ones reproduced in books or as here on the web, and every one is different. Not just subtle differences, but different colours differently applied. She really at this stage was using pochoir (stencil) as an incredibly flexible and beautiful art form. Later Delaunay, Matisse, and Lanskoy would create great lasting works of art in this medium, but the collaboration between Delaunay and Cendrars remains pochoir's finest moment.
Captain Lacroix is Louis Lacroix, a sea captain during the 19th century. His books are still published in French (see http://www.antiqbook.com/boox/mariti/56128.shtml
Great post, thank you and have a nice week.