diff --git a/gtsam/base/Manifold.h b/gtsam/base/Manifold.h
index 1190822ed..c5554fd1a 100644
--- a/gtsam/base/Manifold.h
+++ b/gtsam/base/Manifold.h
@@ -70,7 +70,8 @@ struct is_manifold: public boost::false_type {
 // defaults to dynamic, TODO makes sense ?
 typedef boost::integral_constant<int, Eigen::Dynamic> Dynamic;
 template<typename T>
-struct dimension: public Dynamic {
+//struct dimension: public Dynamic {
+struct dimension : public boost::integral_constant<int, 1> {  // just temporary fix to minimize compiler errors while refactoring
 };
 
 /**
diff --git a/gtsam/base/concepts.h b/gtsam/base/concepts.h
index 68752bdff..6d5a5d74d 100644
--- a/gtsam/base/concepts.h
+++ b/gtsam/base/concepts.h
@@ -41,7 +41,7 @@ template<typename T>
 struct dimension;
 }
 template <typename T> struct traits_x {
-  // todo: remove anything in here ASAP.
+  // TODO: remove anything in here ASAP.
   // This is just here during development to avoid compilation
   // errors while implmenting traits for everything.
   enum { dimension = traits::dimension<T>::value };
diff --git a/gtsam/base/numericalDerivative.h b/gtsam/base/numericalDerivative.h
index 9ee25349d..188647525 100644
--- a/gtsam/base/numericalDerivative.h
+++ b/gtsam/base/numericalDerivative.h
@@ -195,10 +195,10 @@ inline Matrix numericalDerivative21(Y (*h)(const X1&, const X2&), const X1& x1,
 template<class Y, class X1, class X2>
 Matrix numericalDerivative22(boost::function<Y(const X1&, const X2&)> h,
     const X1& x1, const X2& x2, double delta = 1e-5) {
-  BOOST_STATIC_ASSERT_MSG(traits::is_manifold<Y>::value,
-      "Template argument Y must be a manifold type.");
-  BOOST_STATIC_ASSERT_MSG(traits::is_manifold<X2>::value,
-      "Template argument X2 must be a manifold type.");
+  BOOST_STATIC_ASSERT_MSG( (boost::is_base_of<gtsam::manifold_tag, typename traits_x<X1>::structure_category>::value),
+       "Template argument X1 must be a manifold type.");
+  BOOST_STATIC_ASSERT_MSG( (boost::is_base_of<gtsam::manifold_tag, typename traits_x<X2>::structure_category>::value),
+       "Template argument X2 must be a manifold type.");
   return numericalDerivative11<Y, X2>(boost::bind(h, x1, _1), x2, delta);
 }