Sheathed string of christmas tree lights

Claim 1

In a string of lights for a Christmas tree, the combination comprising a light transmitting generally tubular flexible sheath, an electric circuit enveloped by said sheath, a series of electric light sockets connected to said circuit at periodically spaced intervals, individual electric light bulbs in and received by said periodically spaced sockets, said sheath being a flexible membrane, having a set cross section in the shape of the spiral of Archimedes with the ends of the cross-section overlapped so that the sheath is held in place by the force of the set spiral of Archimedes and being capable of being forced to spread apart at any place along its length so as to expose a particular light or a particular light bulb socket and when so spread apart the two cross-sectional ends no longer overlap whereby a light bulb may be readily replaced without removing the entire or a substantial part of the circuit from the sheath, said sheath of said cross-section having a memory so that, when the spreading force is released, the spread apart plastic sill remember to return to the shape of the spiral or Archimedes.