Here's a wonderful example of an early Adolphe Sax tenor saxophone from the 50 Rue St. Georges era. This particular saxophone dates to 1859.
As with all original Antoine Joseph Adolphe Sax saxophones this instrument features the double octave mechanism. The player has to manually trigger the neck/body vent tube switch with the left-hand thumb. We take the modern single automatic octave mechanism for granted today, as it was a major development in modernizing the saxophone. The instrument also features soldered on tone holes and post flanges that go through the body tube. Keywork goes from low B to high F.
This instrument was masterfully restored by Saxquest in 2009 and is currently on display in the Saxquest saxophone museum along with an entire quartet of early 1850-1860's Adolphe Sax saxophones.