I began referring to "heavy rock" in the Times one or two years before the "metal" part crept in. I was writing about "heavy bottom," i.e., prominent bass and deep chords, then "Iron Butt" slipped into my sentences as a logical addendum to the "heavy bottom" thought, then the "iron" from Iron Butterfly and the Led from you-know-who got tossed into the mix. Steppenwolf came along with "heavy metal thunder," referring to a vehicle, and one thing led, as it so often does, to another; the phrase "heavy metal" emerged.