The drawings belong to a personal campaign album. The author is Captain Manuel Isidro Paz and during the peninsular war he was on generals Blunt, Campbell and Bradford's staff.
The album has 140 pages and contains drawn maps from marches,itineraries, and croquis from battles, from February to July 1812. It also has pencil drawings and aquarelles about such themes as daily life, landscapes, portraits and scenes from military life. I took this description from Torre do Tombo's site (the name of the portuguese national archives).
The piece was recently acquired in an antiquarian.
The portuguese historian Claudio Chaby had published some of them. The relevant volume of Chaby's Excerptos Históricos, is on Google:
Unfortunately the drawings were fac similed and with the digitalization they turned quite bad. Look from page 438 to 506 of the PDF file (1228 of the book).
Hope it helps.