This is a suit by the respondent to restrain the petitioner from infringing claims 8 and 9 of reissue patent No. 20,370. The application for reissue was filed September 25, 1936, and granted May 18, 1937. The original patent was No. 1,998,878, applied for March 22, 1932, and granted April 23, 1935, to Theodore Emile Lefort of Paris, France, for a 'Process for the Production of Ethylene Oxide'. The application was based on earlier French patents. The respondent purchased the United States patent in April 1936, and, as a result of its study thereof, the patentee was persuaded to apply for the reissue.
If the reissue patent is valid, no question is now raised as to petitioner's infringement of the claims in suit. The District Court held the patent valid and infringed. The Circuit Court of Appeals affirmed. We took the case because of an apparent conflict with decisions of this court and several Circuit Courts of Appeals, to the effect that a reissue patent must, under the statute, be for the same invention as the original patent. The petitioner also raised a question as to intervening rights which, in the view we take, need not be considered or decided.
Ethylene is a hydrocarbon gas, C2H4. For a long time it was thought impossible directly to oxygenize it to form C2H4O by bringing oxygen and ethylene into contact, though the formation of ethylene oxide by direct oxidation was commercially desirable. Efforts at direct oxidation, instead of producing the oxide, resulted in less desirable oxygenated compounds such as aldehydes. Lefort conceived the idea of effecting the oxidation by catalytic reaction, that is, the use of a substance, which, in some unexplained way, causes a chemical union or reaction when the two substances to be affected are brought into contact in its presence under given conditions. He recognized one incident of the direct oxidation process as applied to ethylene tending to decrease its efficiency, namely, that, in addition to the principal reaction producing C2H4O, there occurs a side reaction by which a portion of the ethylene is converted into carbon dioxide and water, and, to that extent, the ethylene is wasted. He found that, by certain control of the process, this side reaction could be so restricted as not to decrease the production of ethylene oxide below a profitable level.
According to both the original patent and the reissue, ethylene and oxygen are to be introduced into a heated reaction chamber in the presence of a catalyzer. The petitioner insists that the original patent also treats as a mandatory or necessary step the voluntary introduction of water, whereas the reissue in specification and claims 8 and 9 omits this requirement, and therefore describes a different process. The respondent, on the other hand, asserts that as both patents describe the oxygen of air as that which may be used, and as atmospheric air contains moisture, the first, specifying water, and the reissue specifying air, both contemplate the introduction of water in some form and therefore are for the same process. This dispute must be resolved by a comparison of the disclosures of the two instruments. If that comparison leads to the conclusion that the reissue is not for the same invention as the original, the reissue is void as not within the terms of the statute.
We shall postpone discussion of the tests of identity or difference of invention, and the use of expert testimony, to a statement of the criteria of judgment furnished by the language of the specifications and claims of the two documents.
The opening paragraph of the original patent is:
'This invention has for object a process for the production of ethylene oxide which mainly consists in subjecting ethylene to the simultaneous action of the oxygen of air and of water in presence of a catalyzer and, if need be, of hydrogen.'
After referring to the use of hydrogen as optional, the specification deals with the character and composition of metals to be used as catalyzers. It then speaks of the elements to be used to obtain the desired reaction thus: 'The ethylene can be obtained from any source of supply: * *
*'Water can be admitted to the reaction vessel, either in the liquid state, or as steam.
'The oxygen can be the oxygen of the air, this latter gas being introduced in the reaction.'
'The efficiency of the reaction is increased by diminishing the CO2 which is formed, by introduction, in this reaction, of a suitable quantity of water. A suitable quantity of CO2 can also be previously introduced in the reacting gases.'