270 U.S. 390 (1926)
This is a suit for the infringement of the plaintiff's patent for an improvement in welding and cutting apparatus alleged to have been the invention of one Whitford, although the suit embraced other matters this is the only one material here.1 The application for the plaintiff's patent was filed on March 4, 1911, and the patent was issued June 4, 1912, with no evidence carrying Whitford's invention further back.2
The defense is that Whitford was not the first inventor of the thing patented, and the answer gives notice that to prove the invalidity of the patent evidence will be offered that one Clifford invented the thing, his patent being referred to and identified, with Clifford's application filed on January 31, 1911, before Whitford's, and his patent issued on February 6, 1912.3 It is not disputed that this application gave a complete and adequate description of the thing patented to Whitford, but it did not claim it.4
The District Court gave the plaintiff a decree, holding that, while Clifford might have added this claim to his application, yet as he did not, he was not a prior inventor, 297 Fed. Rep. 846.5 The decree was affirmed by the Circuit Court of Appeals, 1 Fed. (2d) 227.6 There is a conflict between this decision and those of other Circuit Courts of Appeals, especially the sixth.7 Therefore a writ of certiorari was granted by this Court, 266 U.S. 596.8
Whether a complete description of an invention in an earlier patent application that does not claim the invention prevents a later applicant from obtaining a valid patent on the same invention?9
Yes. Clifford filed his application containing a complete description on January 31, 1911, prior to Whitford's filing on March 4, 1911, and this description was adequate to disclose the invention to the public upon issuance of Clifford's patent.12 The absence of a claim in Clifford's application does not alter the bar because the invention is made public property by the description in the same manner as if it had been published in a periodical.13 The policy of the patent law demands that the patentee actually be the first inventor.14
The description shows that Whitford was not the first inventor.15
A complete description of an invention in an earlier patent application that does not claim the invention prevents a later applicant from obtaining a valid patent on the same invention.16