  On a Riemann surface $S$ of finite type containing a family of $N$ disjoint
disks $D_i$ (``islands''), we consider several natural conformal invariants
measuring the distance from the islands to $\di S$ and separation between
different islands. In a near degenerate situation we establish a relation
between them called the Quasi-Additivity Law. We then generalize it to a
Quasi-Invariance Law providing us with a transformation rule of the moduli in
question under covering maps. This rule (and in particular, its special case
called the Covering Lemma) has important applications in holomorphic dynamics
which will be addressed in the forthcoming notes.
