THE RACE FOR CHEAP ALUMINUM: HALL VERSUS HEROULT

The factors that determine priority in inventions are illustrated in the development of a commercially acceptable process for preparation of aluminum in 1886 when it was achieved by two young (age 22) men (Hall and Heroult). At least three factors were involved in the parallel achievement. The specific success of Charles Martin Hall in obtaining the US patent was a consequence of a couple of factors. One was likely the assistance of his elder sister; the other was the rule of the United States Patent and Trademark Office concerning priority, viz., first to "reduce to practice" versus the standard in France and other nations, first to submit an acceptable patent application. The Patent and Trademark Office will change rules soon to conform to the practice of other nations.