(dissenting).
While I agree with the conclusion of the majority that appellants’ claimed oils are novel, I do not believe the majority has basis for deciding that the board erred in its obviousness rejection, and I believe their conclusion is contrary to the recent decision of this court in In re Spatz, 55 CCPA ___, 387 F.2d 663, 156 USPQ 39.
In that case, as in this, patentability was urged based upon the presence of a very low maximum amount of an impurity. In that case, as in this, the prior art taught purification techniques suitable to remove at least a portion of the impurity. In that case, as in this, the prior art was silent as to the amount of impurity present in its product. And in that case, as in this, the appellants failed to advance any evidence that the prior art materials differed substantially from their claimed material in the critical element.
In an amendment filed in the prosecution of this application, applicants’ attorney stated:
Applicants have found for a fact that the usual naphthenic charge stock for making transformer oil has a nitrogen content typically in the neighborhood of 50 p.p.m., the oil after acid treatment typically contains nitrogen in amount of 4-8 p.p.m. and the finally treated oil typically contains 1-2 p.p.m. of nitrogen. * * *
Since the references relied upon both provide for acid treatment of their oils, it would appear that their oils typically contain 4-8 p.p.m. of nitrogen. To hold that it is unobvious to have a nitrogen content of less than 4 p.p.m. in the claimed oil therefore seems to me to be erroneous.
Had appellants produced evidence showing the specific reference oils to have nitrogen contents above 4 p.p.m., I would agree that they had made out a case for patentability in view of their assertions of criticality of that maximum nitrogen- content. But such evidence is not in this record. I would therefore affirm.