Measurement.define(:ton) do |unit|
  unit.alias :'short ton', :'short tons', :tons
  unit.convert_to(:cwt) { |value| value * 20.0 }
  unit.convert_to(:lb) { |value| value * 2_000.0 }
  unit.convert_to(:oz) { |value| value * 32_000.0 }