(concurring).
I agree that appellee reduced the invention to practice and that, through the acts of his assignee, he suppressed the invention. Under 35 U.S.C. § 102(g), a second inventor is not entitled to a patent unless the first inventor abandoned, suppressed, or concealed the invention. In an interference the burden of proving abandonment, suppression, or concealment falls on the second inventor, regardless of who filed first. Young v. Dworkin, 489 F.2d 1277, 1279 (CCPA 1974).
This court has consistently held that suppression or concealment, to amount to forfeiture of the right to a patent in favor of a later inventor, must be deliberate or intentional. Pingree v. Hull, 518 F.2d 624, 629 (CCPA 1975); Young v. Dworkin, supra at 1280-81; Woofter v. Carlson, 367 F.2d 436, 54 CCPA 917, 930 (1966), cert. denied, AMP Inc. v. General Motors, 389 U.S. 847, 88 S.Ct. 39, 19 L.Ed.2d 114 (1967); Dewey v. Lawton, 347 F.2d 629, 632, 52 CCPA 1573, 1577-78 (1965); Schnick v. Fenn, 277 F.2d 935, 941, 47 CCPA 1174, 1183 (1960); Gallagher v. Smith, 206 F.2d 939, 947, 41 CCPA 734, 745 (1953). Young v. Dworkin, however, was a harbinger of the outcome of this case. It was not redundancy1 when, speaking for the majority of this court, I wrote “Mere delay, without more, is not sufficient to establish suppression or concealment.” Mere delay is to be contrasted with excessive or unreasonable delay, which, without more, is sufficient to establish suppression or concealment. The four-year delay in this case, without more, is excessive.
Such delay, however, only gives rise to an inference of intent to suppress. Young v. Dworkin, supra at 1281 n. 3. It shifts the burden to the first inventor to explain the *656delay by showing that there was no intent to suppress. Appellee has failed to do so since he has presented virtually no evidence covering the two-and-a-half year gap between reduction to practice and the arrival of attorney Black. This failure decides the case.
The majority indulges in dictum which would engraft onto the statute a policy “favoring . . . the party who expeditiously starts his invention on the path to public disclosure ... by filing a patent application.” (Emphasis added.) It implies that the failure to hire a sufficient number of attorneys to deal with a backlog of patent applications results in forfeiture of the patent right to one who has been “expeditious.” However, not even diligence is required after reduction to practice. Bowers v. Valley, 149 F.2d 284, 287, 32 CCPA 1039, 1045 (1945).
The public policy referred to in Brokaw v. Vogel, 429 F.2d 476, 480, 57 CCPA 1296, 1301 (1970), is that prescribed by Congress in § 102(g). The party with the right to a patent is the first inventor unless he has abandoned, suppressed, or concealed the invention. The policy is concerned with the action or inaction of the first inventor — not that of his opponent. Brokaw was awarded “priority” by the court “because he is the one who was the first to start the invention on its way to being disclosed to the public and because, so far as the record here shows, the public would never have gained knowledge of it through the efforts of Vogel.” (Emphasis added.)
The “expeditious” standard created by the majority is not the standard of deliberate or intentional suppression required by the statute. Nor do the cases cited by the majority support it. In Pingree v. Hull, supra, intent to suppress was found as a result of a five-and-a-half year delay and spurring; similarly, in Young v. Dworkin, supra, intent to suppress was found as a result of a two-and-a-half year delay during which the inventor prepared for commercial production. If the standard prescribed by the statute is to be changed, that is a matter for the Congress. In re McKellin, 529 F.2d 1324, 1332 (CCPA 1976) (Markey, C. J., concurring).
. The error of the superfluous comment in footnote 10 of the majority opinion is demonstrated by the statement of the obvious in the opinion itself: “Surely, the word ‘mere’ does not imply a total absence of a limit on the duration of the delay.” The language in Young v. Dworkin was taken from Gallagher v. Smith, 206 F.2d 939, 946, 41 CCPA 734, 743 (1953).