“ Both he and Mr. Madded examined the patents of the claimant, and Mr. Madden also examined the correspondence on file. From the beginning the latter insisted that the invention of the stamp book issued by the Department was his own, being independent of the claimant's patent. In March, 1909, the Third Assistant Postmaster-General addressed a letter to the claimant's attorney, expressly asserting that the Department's stamp book was not an infringement. It was in these circumstances that the government commenced the manufacture of its stamp books on March 26, 1900. ”

“ Madden learned for the first time that it was claimed that there were letters patent covering the proposed stamp book, and before issuing the same to the public he requested the Assistant Attorney General for the Department to examine all such claims and letters patent, and to advise him whether his book would constitute an infringement. ”

“ It is apparent that these facts furnished no basis for a finding of implied contract on the part of the government to pay for the use of the invention,-the only ground upon which the petitions were cognizable in the court of claims. ”