His Master's Voice

    Number of validations : 1902

Image challenge

This recording is probably the oldest understandable record of a human voice singing.

The author claims authorship of the process and has written a book in which he expresses his grievances against a globally renowned scientist.
1. In this work, he attributes to him a patent number dated December 19, 1877, what is it?
This scientist filed hundreds of patents, including one on February 19, 1878.
2. What is this patent's number as it appears in the original description?
On the last page of this description, he mentions another one from March 26, 1877.
3. Under which number does he mention it?
(Example: 264879 747,969 601)