Heating coil
FIG. 1 is a top plan view of a heating coil showing my design disposed in a radiant heater; 
     FIG. 2 is a top plan view of the heating coil shown in FIG. 1; 
     FIG. 3 is a side elevation view thereof; 
     FIG. 4 is a bottom plan view thereof; 
     FIG. 5 is a top plan view of the heating coil of FIG. 2, viewed through a glass surface when the heating coil is energized to illuminate through said glass surface; 
     FIG. 6 is a second embodiment of a heating coil showing my new design disposed in a radiant heater; 
     FIG. 7 is a top plan view of the heating coil shown in FIG. 8; 
     FIG. 8 is a side elevation view thereof; 
     FIG. 9 is a bottom plan view thereof; and, 
     FIG. 10 is a top plan view of the heating coil shown in FIG. 7, viewed through a glass surface when the heating coil is energized to illuminate through said glass surface. 
     The broken line showing of a radiant heater in FIGS. 1 and 6, and of a rod of a radiant heater in FIGS. 5 and 10, is for illustrative purposes only and forms no part of the claimed design. 
     The broken line showing of a glass surface in FIGS. 5 and 10 is for illustrative purposes only and forms no part of the claimed design.