§ 233. Quality marks; description. All quality marks applied to any
article shall be equal in size and equally visible, legible, clear and
distinct and no quality mark which is false, deceptive or misleading
shall be applied to any article or to any descriptive device therefor.
No more than one quality mark shall be applied to any article and such
quality mark shall be applied to such article in only one place thereon
except as elsewhere in this article specifically permitted.

Wherever in this article provision is made for marking the number of
parts or percentage of metals, such number or percentage shall refer to
weight and not to volume, thickness or any other basis.