  Using the Finite Size Scaling Renormalisation Group we obtain the
two-dimensional flow diagram of the Blume-Capel model, for S = 1 and S = 3/2.
In the first case our results are similar to those of Mean Field Theory, which
predicts the existence of first and second order transitions whith a
tricritical point. In the second case, however, our results are different.
While we obtain, as in the S = 1 case, a phase diagram presenting a
multicritical point, the Mean Field approach predicts only a second order
transition and a critical end point.
