Assertion: flask's wall | /r/HasProperty | silvered on the vaccum
Facets:
Source sentences:
text: it consists a double walled glass vessel having a vaccum between the walls.both these walls are silvered on the vaccum side.no heat can enter or leave the inner flask by convection oor conduction across vaccum.a small amount of heat can be gained by the flask through by radiation but the silver surface to control radiant heat and reduce it to a minimum