This beautiful door knob was made by the P & F Corbin Company in New Britain, Connecticut. The Cairo pattern first appeared in their 1905 catalog.
This knob appears to be a bronze-cast piece. Door knobs made before 1900 and immediately after by the eastern coast companies often times were bronze cast, as well as brass. From the dark hue that this knob has, our guess is that it is bronze.
The pattern consists of six leaf sprays projecting from a center daisy. The top of the knob is crimped onto the base, giving the knob a belt around its edge.
This fine heavy knob measures 2 1/4 inches across.