  The heat capacity of low-dimensional spin systems is studied using
theoretical and numerical techniques. Keeping only two energy states, the
system is mapped onto the two -level-system (TLS) model. Using the low
temperature Lanczos method, it is confirmed that the behavior of $T_{M}$ and
the energy gap as functions of the control parameter is the same in the two
models studied; a conclusion that can probably be extrapolated to the general
case of any system that possesses an energy gap.
