Abstract: A damper is provided which includes a first cylinder containing a viscous fluid. The first cylinder is sealed at both ends by end plates. The first cylinder is adapted for connection to a structure such as a building or a bridge. A piston head within the first cylinder is adapted for reciprocation with respect to the first cylinder. A piston rod is connected to the piston head. The other end of the piston rod extends through the end plate and is adapted for connection to the structure. A second piston rod extends from the piston head through the second end plate. A first ring surrounds the piston head and is constructed from a material having a high coefficient of thermal expansion such as plastic. A second ring surrounds the first ring and is constructed from a material having a low coefficient of thermal expansion such as metal.