A pound of feathers is heavier than a pound of gold, if we assume that feathers are measured in pounds avoirdupois and gold is measured in pounds troy.

With the same assumption, an ounce of gold is heavier than an ounce of feathers, since one troy ounce is about 1.09714 avoirdupois ounces.

The explanation that there are 16 ounces in a "feathers pound" and only 12 ounces in a "gold pound" is incomplete, since the ounces are different in the two cases; but we'll give 50% credit on this one in an elementary class (30% credit maybe in advanced classes).

An "apparently reliable" resource for this thread might be the one at Rowlett, Univ North Carolina. (Link to ounces page) He seems to have done a lot of work on odd units.

John