Specification of John Henry Johnson
Subtitle: instruments for assisting the sense of hearing
Publisher: Great Seal Patent Office
Published: 1861
Place of publication: London
Language: eng
Subjects: Hearing Aids
Notes: Cover title.

At head of title: A.D. 1860, 26th December. No. 3164.

John Henry Johnson, of 47, Lincoln's Inn Fields, in the county of Middlesex, and of 166, Buchanan Street, in the city of Glasgow".