E. I. Du Pont De Nemours & Co. v. Glidden Co‪.‬

We have again examined the record as to Doerflingers prior use in 1913-1919, and are still of opinion that it was not adequately proved. We may assume that he did on occasion reduce viscosity below Flahertys limit, but what he used, except experimentally, was solution 415, and the viscosity of that is most uncertain. Doerflinger used acetic acid to stop the reaction of ammonia, the reducing agent; the more ammonia that combined, the greater the reduction in viscosity. He added enough acetic acid to neutralize two-thirds of the ammonia; and after its addition the solution was neutral, not acid. The defendants experts allowed either all the ammonia, or much more than a third to combine; Schlatter, one of plaintiffs witnesses, after adding the amount of acetic acid specified by Doerflinger, found that the result was acid; more than a third of the ammonia had been used. Naturally there was a greater reduction of viscosity. Clark, the other, did not test to see whether the solution was neutral or not. Moreover, the temperatures of Doerflingers experiments could not be reproduced, as they were not accurately measured at the time, and, besides, his memory was not reliable after nearly twenty years. Therefore, whatever Doerflinger did, it is not definitely proved that he discovered a lacquer suitable in other respects, and of thick covering, produced by keeping within 4.6 seconds viscosity. If in his experiments he chanced upon some such, it was not an anticipation, unless he came to rest upon a formula which contained the elements of the patented composition. Lacquer made under formula 415 made no impression upon the art, either by its appearance or disappearance; and it is improbable that this would have been so, had it been that composition which in 1921 was at once recognized as a new and important advance. This circumstance fortifies our doubts as to the identity of the two, as it did before.