Specification of Joseph Francis Pratt
Subtitle: instruments for relieving deafness
Publisher: Great Seal Patent Office
Published: 1861
Place of publication: London
Language: eng
Subjects: Hearing Aids; Deafness; Therapy
Description: Patent for "improvements in instruments for receiving and transmitting sound, particularly adapted to the relief of deafness".
Notes: Cover title.

At head of title: A.D. 1860, 6th December. No. 2990.

"Joseph Francis Pratt, of Oxford Street, in the county of Middlesex, surgical instrument maker".