As to Essai sur l'infanterie légère, there existed two online versions:

Googlebook: https://books.google.com/books?id=-BZOAAAAYAAJ

ETH: https://www.e-rara.ch/zut/wihibe/content/titleinfo/9645667

They were both published in 1814, but different in typesetting. Since the 1864 edition is the third edition, could we attest which one was the first, which one was the second?