The invention in controversy is a method and apparatus for generating steam, and is primarily intended for use in connection with motor vehicles. The invention as a method is stated in count 3, as follows:

“(1) In a steam generator, the method of causing positive circulation within the generator consisting in creating a difference in pressure between portions of the generator and causing such differential pressure to operate mechanical water forcing means for supplying water from the portion of lower pressure to the portion of higher pressure.”

And as apparatus is stated in count 9, as follows:

“ (9) In a generator for generating steam, the combination of a pressure chamber, and a heating coil connected at both ends with the pressure chamber, 'and a unit steam pump having its steam end connected between the steam end of the heating coil and the upper part of the pressure chamber .and having its water end connected between the lower part of the pressure chamber and the inlet end of the heating coil.”

Crabb filed his application on January 21, 1921, and is the senior party. Barlow filed on August 30, 1922, and the burden of proof is accordingly upon him. The Examiner of Interferences found upon the evidence that Crabb had actually reduced the invention to practice not later than June 30, 1920, by installing and successfully operating the same upon an automobile, but under the evidence found no earlier date than this for Crabb’s conception. It is the claim of Barlow that he conceived the invention and reduced it to practice in the year 1917 by a like successful use upon an automobile. It was found, however, by the Examiner, that this alleged operation was but an unsuccessful experiment, and did not amount to an actual reduction to practice. The Examiner therefore found that Barlow had not reduced the invention to practice, prior either to Crabb’s actual reduction to practice in 1920, or his constructive reduction to practice on January 21,1921, and that Barlow was lacking in the necessary diligence during that period, and for this reason the Examiner awarded priority to Crabb.

*1006An appeal was taken by Barlow to the Board of Examiners in Chief, who affirmed the decision of the Examiner of Interferences, and the decision of the board was affirmed upon appeal by the Commissioner of Patents, from whose decision the present appeal was taken. We have examined the evidence in the ease, together with the briefs of the respective counsel, and wé find no reason apparent in the record to require a reversal of the concurrent decisions below.

The decision of the Commissioner of Patents is therefore affirmed.