A trip to the Performing Arts Library at Lincoln Center this past week included something equally interesting and fascinating to this researcher: a beautiful 1847 edition of Manuel García's Traité Complet de L'Art du Chant published by Fuzeau (Courlay, France) in 2005.
Original, you say? Very much so. And the musical bible to which all singers and voice teachers should acquaint themselves. Why? García is the father of voice science.
You can find more accessible editions on the Download page along with García's Hints on Singing (1894).