Harold Ladd Pierce v. Herman Muehleisen and Muehleisen Perlite Processing, Inc.

Appellees filed an action in the trial court seeking a judgment declaring United States patent No. 2,501,962 ■ (hereafter referred to as the Pierce patent) invalid. After trial duly had the trial court held the said patent invalid on several grounds, among which is non-invention. We think the finding as to non-invention is correct and the judgment should be affirmed on that ground.

The Pierce patent, here in issue, teaches a two-step process for commercial expansion of perlite, a glassy volcanic rock which, when expanded, forms material suitable for various commercial uses, that is, as a light weight concrete and plaster aggregate, for roof and wall slabs, for insulation, as a filler for paints. Its geological background is apparent from the definition of perlite offered in the Encyclopedia Americana, vol. 23, pages 606-607:

Pierce developed what he describes as:

35 U.S.C.A. § 103 provides as follows:

The district court found that the scope of the art extends to various expansible materials other than perlite, the subject of the patent, and that the pre-heating step employed in processing such other materials constituted such “road signs” that the adaptation of the method to…