Primary dry cell having a novel venting closure

A magnesium dry cell comprising a metal anode cup having an open end and having a cathode mix therein, a central cathode rod protruding through said open end of said anode cup, and a closure for said open end, said closure including a central bore having at least three protrusions in contact with said cathode rod and adapted to be in interference fitting relationship when positioned on said central cathode rod, said central bore including a first section having a uniform and smooth surface which is slightly smaller in diameter than the diameter of said cathode rod and a second section extending downwardly from said first section and tapering outwardly away from said cathode rod and a venting sleeve defined by an annular groove in said closure and being disposed proximate said central bore, said venting sleeve being adapted to be urged outwardly away from said central cathode rod upon the development of a predetermined gas pressure within said cell thereby permitting venting of gas from the interior of said cell.