Mid Nineteenth Century
The valves are used to change notes.
Valves were added over the course of the 19th century
Valves for brass instruments weren't developed until around the year 1800.
Yes, but there are trombones that do have valves. Bugles- no valves
They are called valves.
Not all brass instruments have valves. For example, the trombone has a slide. The trumpet, euphonium, and french horn have three valves.
Valves!
Brass instruments such as the trumpet, cornet, French horn and tuba.
I'm no brass instrument, but rotary valves are used for several instruments. French horns all seem to have them. They're pretty common on tubas as well. There are even some rotary valve trumpets out there. I don't know, though, anything about the advantages and/or disadvantages of rotary valves as opposed to the piston valves that seem to be more common for most brass instruments.
No, a saxophone has keys like other woodwind instruments. Brass instruments have valves.
Trombones are played by moving a slide, while other brass instruments use valves to change notes.