Note 22 — Chapter IV · CONTEMPORARY DOCUMENTS.
Reading edition
[This limit is a mistake of Professor Böttger’s. The longitudinal tone of an unstrained iron or steel wire 10 inches long would be a note about four octaves above the middle c of the piano; whereas, in fact, any note of the whole piano-gamut down to the lowest note, can be reproduced by such a wire, as stated in preceding footnote.]—S. P. T.