Keywords: Life in Motion Fig 39.png en Fig 39 ”Tuning-fork arranged for causing a smoked-glass plate a to vibrate b electro-magnet; current passes in at c along limb of fork d along platinum wire to platinum contact at e thence by wire f to electro-magnet b thence back to battery by wire from g When b is magnetised the limbs of the fork are drawn together and contact is broken at e The limbs then fly back and again make contact at c and so on Life in Motion or Muscle and Nervehttps //archive org/details/b21929786 John Gray McKendrick 1892 1926 Life in Motion book Tuning forks |