Antique book from 1787 Regras das sinco ordens da arquitetura

You really need the services of an Antiquarian book seller to help you out with this one, here is a link:

http://www.abebooks.com/?cm_mmc=ggl-_-CA_AbeBooks_Brand-_-Top+Brand-_-abebooksabebooks

Vignola was an assistant to Michaelangelo and wrote a book titled "The 5 Orders of Architecture".  Yes, your book is in Portuguese and is a reprint of his original, which was published in 1563, and has been translated many times.  His book undertook to formulate the rules for proportioning the orders appearing in the buildings of the ancient Romans.  It is one of histories most published works and  is considered by many to be an authority.  It has been in continuous use since he wrote it, being translated till the present day.

If I were you, I would take more pics and send them to the Metropolitan Museum of Art, who has some early copies of his book.  You quite possibly might have a very rare edition and since I know that the Met has some early copies of the original work, I would most definitely contact them.  You have nothing to lose.