diff --git a/include/GyotoRegister.h b/include/GyotoRegister.h
index 0d4bac31..73b0b155 100644
--- a/include/GyotoRegister.h
+++ b/include/GyotoRegister.h
@@ -82,9 +82,29 @@ namespace Gyoto {
    *            function inside it throws an Gyoto::Error. If nofail
    *            is 2 or more, such conditions are silently ignored. If
    *            nofail is one, those conditions trigger a warning.
+   *
+   * \return void* handle to the dlopen'ed plug-in.
    */
   void * loadPlugin(   char const * const plugname, int nofail = 0);
+
+  /**
+   * \brief Check whether a given plug-in has already been loaded
+   *
+   * \param[in] plugname std::string Plug-in name.
+   */
   bool havePlugin(std::string plugname);
+
+  /**
+   * \brief Load a plugin by name, only if not loaded yet
+   *
+   * \param[in] plugname std::string Plug-in name.
+   *
+   * \param[in] nofail int Unless nofail evals to true, the inability
+   *            to find a plug-in or to run the initialization
+   *            function inside it throws an Gyoto::Error. If nofail
+   *            is 2 or more, such conditions are silently ignored. If
+   *            nofail is one, those conditions trigger a warning.
+   */
   void requirePlugin(std::string plugname, int nofail = 0);
 }
 
diff --git a/include/GyotoScenery.h b/include/GyotoScenery.h
index f8a9c518..30ef2468 100644
--- a/include/GyotoScenery.h
+++ b/include/GyotoScenery.h
@@ -406,8 +406,8 @@ class Gyoto::Scenery
   void secondary (bool sec) ; ///< Set ph_.secondary_
   bool secondary () const ; ///< Get ph_.secondary_
 
-  void parallelTransport (bool sec) ; ///< Set ph_.secondary_
-  bool parallelTransport () const ; ///< Get ph_.secondary_
+  void parallelTransport (bool pt) ; ///< Set ph_.parallel_transport_
+  bool parallelTransport () const ; ///< Get ph_.parallel_transport_
 
   void maxiter (size_t miter) ; ///< Set ph_.maxiter_
   size_t maxiter () const ; ///< Get ph_.maxiter_