David Orrell

David Orrell. Writer and Mathematician

Truth or Beauty: errata

    Pg 18. When discussing the Pythagorean ratios of musical consonances, I wrote that the ratios 2:1, 3:2 and 4:3, played on separate strings, would produce a major triad. As McGill music professor Jon Wild pointed out by email, this is incorrect, as "you need a major third, whose ratio is 5:4, for a major triad." He goes on: "The proportion 2:3:4 gives an octave divided 'authentically', in music-historical terms, i.e. at the 5th (C-G-C), if we are talking about frequencies, and an octave divided 'plagally', i.e. at the fourth (C-F-C), if we are talking about string lengths. String lengths were the only known basis for ratios of musical intervals until the late Renaissance. The major triad would be given by the proportion 4:5:6 in terms of frequency, and 10:12:15 in terms of string lengths."

    Pg. 51. The speed of light is calculated by dividing the distance traveled by the time, not vice versa as stated.

    Pg. 76. The line "radius of the nucleus was about 10^32 centimeters" should read 10^-12 centimeters.

    Pg. 76. The line "the loss of a proton in the nitrogen atom turned it into oxygen" is incorrect. The alpha particle knocks out one protein, but donates two others.

    Pg. 144. The line "the beta particles used by Rutherford to probe the structure of the atom" should refer instead to alpha particles.

    Pg. 219. The line "the RNA is transcribed to make a protein molecule" should read "the RNA is translated".

    Thanks very much to readers who have written in with comments and corrections.