diff --git a/lemon/capacity_scaling.h b/lemon/capacity_scaling.h
--- a/lemon/capacity_scaling.h
+++ b/lemon/capacity_scaling.h
@@ -301,6 +301,10 @@
 
     /// @}
 
+  protected:
+
+    CapacityScaling() {}
+
   public:
 
     /// \brief Constructor.