Tuning forks
Circular receptor hearing device, ca. 1875
Bilateral circular receptor, 19th century
Stethoscope tube, ca. 1840
Black metal conversation tube, 19th century
Open ball receptor, 19th century
Itchin model adjustable resonator hearing device, ca. 1875
Closed ball resonator hearing device, ca. 1875
Conversation tube with pipe-shaped receptor, 19th century
Rubber conversation tube, 19th century
Rubber conversation tube, 19th century
Heap's topophone.
Marshall's Collector ear trumpet, 19th century
Elliptical receptor or artificial hand, ca. 1875
Black ear trumpet, 19th century
Super-ear, ca. 1926
Small ear trumpet, 19th century
Aurolese phone floral tube, ca. 1810
Super-Ear, ca. 1929
Aurolese phones, 1830