plurality of vertically spaced horizontally extending insulating plate members 23 26 having apertures provided therein 18 21 to accommodate the vertical opening and closing movements of the movable rod shaped contact 5 as shown more clearly in fig2 of the drawings the establishment of arcing 13 results in a plurality of series arc portions 13a 13b 13c and 13d which are subjected to transverse zig zag flows of arc extinguishing fluid in the manner indicated by the arrows 27 30 also it will be noted that as previously mentioned the two pressure generating chambers 7 10 are so arranged and isolated in a compartmentalized fashion from the adjacent transverse flow passageways 9 12 as to force the two flows 28 30 in a circuitous fashion prior to the subsequent injection of the thus cooled fluid 14 into the arc portions 13b 13d a distinct effort is made in the instant disclosed construction to isolate the pressure generating chambers 7 10 from the remote point of fluid ejection 9 12 this is more clearly illustrated in fig2 with particular reference being directed to the fluid flow direction arrows 27 30 as shown in fig2 a vertically extending plate portion 33 constituting a partition means 34 is disposed laterally of the.