Wrongful terminology and formulas in the Bruce Candy's Gospel "Metal Detector Basics and Theory" http://www.minelab.com/consumer/xstandard/files/ML_08_007WhitePaper8.pdf Page 5 and following: WRITTEN "mineralisation, mineralized". Should be "ferromagnetism, ferromagnetic". 1/(a 2 + z 2 )3 . Should be a 4 /( a 2 + z 2 )3 2nIa 2 /(a 2 + z 2 )3 / 2 × 2na 2 /(a 2 + z 2 )3 / 2 = 4n 2 Ia 4 /(a 2 + z 2 )3 Page 14: WRITTEN ω = 2π / τ . Should be ω = 1/ τ . Since ω = 2π . f 1 0.159 f = = . 2π τ τ Page 15: WRITTEN frequency in Hz is because , then the characteristic Page 18 and following: WRITTEN "superparamagnetic". Should be "ferromagnetic". It is necessary, we amateur designers to write our "Metal Detecting Bible" containing more formulas and graphs. * * * 1