[en] The limiter in a tokamak draws significant particle and energy fluxes from the plasma and sharply reduces the interaction between the plasma and the wall, thereby protecting the wall from damage and protecting the plasma from catastrophic contamination. The temperature of a movable limiter in the T-10 tokamak has been measured using the IR emission from the surface of the limiter. When the results of these measurements are interpreted with reference to certain models for the boundary layer at the wall it becomes possible to calculate the heat flux to the limiter. This heat flux is 2--3 kW/cm² in normal discharges and ranges up to 10 kW/cm² in discharges with disruptions. The total power drawn by the limiter is thus comparable to the power deposited in the discharge under these conditions. The measurements reveal that the radial decay of the longitudinal energy flux in the peripheral layer of the plasma column is exponential. The results also yield the constant of this decay. During discharges with disruptions, in the initial and final stages of normal discharges and also when microwave power is injected into a plasma, there is a highly nonuniform heating of the limiter surface. This nonuniformity indicates a definite structure for the peripheral plasma. An overall result of this study is that the limiter can be used successfully in a role in addition to its primary role. Specifically, it can be used as a diagnostic probe in a close contact with the plasma which is not achievable by other means