Recall that for a Hausdorff locally convex space $X$ the Mackey topology $\tau (X^*,X)$ is the topology in its topological dual $X^*$ of uniform convergence on all weakly compact absolutely convex subsets of $X$.
Does this definition amount to saying the following?
Let $\mathcal{C}$ be the family of absolutely convex and $\sigma (X,X^{*})$-compact subset of $X$ let $\{x_n^*\}_n\subset X^*$ be a sequence and $x^*\in X^*$ then :
$$ x_n^*\overset{\tau (X^*,X)}{\longrightarrow} x^* \Longleftrightarrow \forall K\in \mathcal{C}~:~\text{$x_n^* \longrightarrow x^*$ uniformly on $K$} $$