The design and application of high temperature thermal analysis equipment is described in this paper. Radiation emitted from the inductively heated samples impinges on an ir semiconductor device, the output of which is amplified and displayed on an X‐Y two‐pen recorder. Small heat effects associated with condensed state phase transitions can readily be detected using the techniques of thermal analysis (TA), derivative analysis (DA), or differential thermal analysis (DTA). Solid state transformations found in thorium dicarbide are illustrated using the various TA techniques. Data presented for phase changes in the uranium present in hypostoichiometric uranium dioxide show that isothermal enthalpy changes of <7 cal can be detected by the TA apparatus when using the DA mode of operation.