not shown electrodes 3 are connected to lead wires 4 and 5 which extend through a glass seal 6 in a mount stem 7 to the electrical contacts of base 8 fixed at both ends of the sealed glass envelope a pair of contact pins 11 and 12 extend from each of the bases 8 and are electrically connected to associated leads 4 and 5 the inert gas is typically argon or a mixture of argon and krypton at a low pressure of about 10 4 torr the inert gas acts as a buffer or means for limiting the arc current the envelope 2 includes an inner wall 2a having a segmented first coating or layer 14 of metal oxide particles a second or conductive layer 15 covering the layer 14 and any exposed portions of the inner wall 2a along the length of the tube 2 a protective or barrier layer 16 covering the layer 15 and a phosphor layer 17 covering the barrier layer 16 these layers are described more fully below the layer 14 comprises spaced segments 14a and 14b disposed adjacent associated end portions 34 a 34 and 34 b 34 at each end of the lamp 1 each of the segments 14a and 14b extends from a location adjacent its associated electrode 3 toward the center of the envelope an.