Thermal Conductivity of Solid $^{4}$He in Vycor

In addition to non-classcial rotational inertia (NCRI) observed in torsional oscillator (TO), we have carried out thermal conductivity measurement of solid $^{4}$He embedded in porous Vycor glass to search for possible anomaly related to the onset of NCRI. Because of the high thermal conductivity of bulk solid $^{4}$He, it is difficult to resolve any small `extra' thermal conductivity signal due to the onset of supersolidity. However, when it is confined in porous Vycor, the thermal conductivity of solid $^{4}$He is significantly reduced. This makes it easier to single out possible anomaly. Preliminary measurements show a rounded peak in the thermal conductivity near 0.1 K.