Oliver Wendell Holmes, Jr.

“ It is said that oil does it by coating the metal particles and that of course a substance in solution could not do that. There is no 'of course' as to what nature can do, except as proved by observation and experiment. A substance in solution can combine chemically with another and become a solid. Whether a given thing will unite mechanically or whether by its presence it will promote an activity in which it does not share, is to be found out by trial not by reasoning, and the petitioner agrees that in this case we do not know. ”

“ It is disclosed that it was well known there were other substances besides oil that had the preferential affinity and that could be used. The nature of the affinity is not specified and it cannot be confined to the kind of action shown by oil. It is neither said nor implied that the added element must be insoluble or that it must coat the metal, although it is assumed in accordance with the prevailing theory that the metal will be coated when the oil mentioned in the claims is used. All that is required is that in some effective way the other substance should pick the metal out. ”

“ The public was directed to make a 'simple preliminary test to determine which oily substance yields the proportion of froth or scum desired.' The patent having been held good as to the oils although experiment was necessary to find out what oil would work best with a given ore the disclosure was an anticipation although experiment might be necessary to chose among the substances having the required affinity the one that would produce the best result. ”