NOVELTY - A cartridge comprises several spaced-apart monoliths (8,9,10) defining several channels for gas flow. Each monolith imparts a swirl to gas flowing through the channels. Adjacent monoliths impart swirls that are of different directions.    USE - As a cartridge e.g. reactor cartridge (claimed). Also use in the field of catalytic fuel reforming, to make hydrogen, which is then used in generating electricity through a fuel cell; in other industrial processes such as oil and gas refining, ammonia and fertilizer production, hydrogenation of oils and chemicals, and iron ore reduction; and as a catalytic or non-catalytic combustor and simple heat exchanger.    ADVANTAGE - The corrugations of the strips in adjacent monoliths are oriented differently, so that successive monoliths impart different swirls to the gases, so as to promote mixing of gases and better heat transfer from the exterior to the interior of the cartridge. The all-metal construction facilitates heat transfer through the entire reactor, and avoids the problems associated with packed ceramic beds.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) a reactor cartridge comprises several spaced-apart monoliths including a pair of flat and corrugated strips which are spirally wound, where at least some of the corrugated strips have corrugations which are oblique relative to a longitudinal axis of the strip, and where corrugations of adjacent monoliths are oriented in different directions; and    (2) making a reactor cartridge involves: (a) affixing pairs of metal strips including a flat strip and a corrugated strip to a mandrel, where the pairs of strips are affixed in series along a length of the mandrel, where corrugated strips of adjacent pairs have corrugations which are oriented in different directions; (b) winding the pairs of strips around the mandrel to form several monoliths; and (c) placing the monoliths in an enclosure.    DESCRIPTION OF DRAWING(S) - The figure shows a perspective view of a portion of a cartridge.    corrugated strips (1,2,3)    flat strips (4,5,6)    monoliths (8,9,10)    spiders (11,12,13)    fragmentary screened portion. (17)