diff --git a/Cantera/src/Func1.cpp b/Cantera/src/Func1.cpp
index d4d39a453..6fcc8d53f 100644
--- a/Cantera/src/Func1.cpp
+++ b/Cantera/src/Func1.cpp
@@ -1,5 +1,7 @@
 #include "Func1.h"
 #include "stringUtils.h"
+#include "global.h"
+
 using namespace std;
 
 namespace Cantera {
@@ -13,12 +15,24 @@ namespace Cantera {
 
     Func1& Sin1::derivative() const {
         Func1* c = new Cos1(m_c);
-        return newTimesConstFunction(*c, m_c);
+        Func1* r = &newTimesConstFunction(*c, m_c);
+#ifdef DEBUG_FUNC
+        cout << "Sin1::derivative: \n";
+        cout << "function = \'" + write("x") + "\'\n";
+        cout << "derivative = \'" + r->write("x") + "\'\n";
+#endif 
+        return *r;
     } 
 
     Func1& Cos1::derivative() const {
         Func1* s = new Sin1(m_c);
-        return newTimesConstFunction(*s, -m_c);
+        Func1* r = &newTimesConstFunction(*s, -m_c);
+#ifdef DEBUG_FUNC
+        cout << "Cos1::derivative: \n";
+        cout << "function = \'" + write("x") + "\'\n";
+        cout << "derivative = \'" + r->write("x") + "\'\n";
+#endif 
+        return *r;
     }
 
     Func1& Exp1::derivative() const {
@@ -30,11 +44,23 @@ namespace Cantera {
     }
 
     Func1& Pow1::derivative() const {
-        Func1* f = new Pow1(m_c - 1.0);
-        if (m_c != 1.0) 
-            return newTimesConstFunction(*f, m_c);
-        else
-            return *(new Const1(1.0));
+        Func1* r;
+        if (m_c == 0.0) {
+            r = new Const1(0.0);
+        }
+        else if (m_c == 1.0) {
+            r = new Const1(1.0);
+        }
+        else {
+            Func1* f = new Pow1(m_c - 1.0);
+            r = &newTimesConstFunction(*f, m_c);
+        }
+#ifdef DEBUG_FUNC
+        cout << "Pow1::derivative: \n";
+        cout << "function = \'" + write("x") + "\'\n";
+        cout << "derivative = \'" + r->write("x") + "\'\n";
+#endif 
+        return *r;
     }
 
     string Func1::write(std::string arg) const {
@@ -314,6 +340,11 @@ namespace Cantera {
     }
     
     Func1& newCompositeFunction(Func1& f1, Func1& f2) {
+        //#ifdef DEBUG_FUNC
+        //cout << "creating new composite function." << endl;
+        //cout << "f1 = " << f1.write("x") << "  " << f1.ID() << endl;
+        //cout << "f2 = " << f2.write("x") << "  " << f2.ID() << endl;
+        //#endif
         if (isZero(f1)) {
             delete &f1; delete &f2;
             return *(new Const1(0.0));
@@ -337,11 +368,6 @@ namespace Cantera {
             delete &f2;
             return *(new Pow1(c1c2));
         }
-        if (isTimesConst(f1)) {
-            Func1& p = newTimesConstFunction(f2, f1.c());
-            delete &f1;
-            return p;
-        }
         return *(new Composite1(f1, f2));
     }
 
@@ -364,6 +390,15 @@ namespace Cantera {
         if (c == 0.0) {
             return f;
         }
+        if (isConstant(f)) {
+            doublereal cc = f.c() + c;
+            delete &f;
+            return *(new Const1(cc));
+        }
+        if (f.ID() == PlusConstantFuncType) {
+            f.setC(f.c() + c);
+            return f;
+        }
         return *(new PlusConstant1(f, c));
     }
 
diff --git a/Cantera/src/Func1.h b/Cantera/src/Func1.h
index 4e5b47775..246845d3e 100644
--- a/Cantera/src/Func1.h
+++ b/Cantera/src/Func1.h
@@ -11,6 +11,9 @@
 #ifndef CT_FUNC1_H
 #define CT_FUNC1_H
 
+#undef DEBUG_FUNC
+
+
 #ifdef WIN32
 #pragma warning(disable:4786)
 #pragma warning(disable:4503)
@@ -224,8 +227,6 @@ namespace Cantera {
         Sum1(Func1& f1, Func1& f2) {
             m_f1 = &f1;
             m_f2 = &f2;
-            if (m_f1 == m_f2) 
-                cout << "Same functions!" << endl;
             m_f1->setParent(this);
             m_f2->setParent(this);
         }
@@ -300,7 +301,6 @@ namespace Cantera {
         }
 
         virtual ~Product1() {
-            //cout << "In Product1 destructor, deleting" << m_f1 << " " << m_f2 << endl;
             delete m_f1;
             delete m_f2;
         }
@@ -379,7 +379,6 @@ namespace Cantera {
         }
 
         virtual ~PlusConstant1() {
-            //cout << "PlusConstant1: deleting " << m_f1 << endl;
             delete m_f1;
         }
         virtual int ID() const { return PlusConstantFuncType; }
@@ -413,7 +412,6 @@ namespace Cantera {
             m_f2 = &f2;
         }
         virtual ~Ratio1() {
-            //cout << "Ratio1: deleting " << m_f1 << " " << m_f2 << endl;
             delete m_f1;
             delete m_f2;
         }
@@ -465,11 +463,22 @@ namespace Cantera {
             return dup;
         }
         virtual Func1& derivative() const {
-            Func1& d1 = m_f1->derivative();
-            Func1& d3 = newCompositeFunction(d1, m_f2->duplicate());
-            Func1& d2 = m_f2->derivative();
-            Func1& p = newProdFunction(d3, d2);
-            return p;
+            Func1* d1 = &m_f1->derivative();
+
+            Func1* d3 = &newCompositeFunction(*d1, m_f2->duplicate());
+            Func1* d2 = &m_f2->derivative();
+            Func1* p = &newProdFunction(*d3, *d2);
+#ifdef DEBUG_FUNC
+            cout << "Composite1::derivative: \n";
+            cout << "f1 = " << m_f1->write("x") << endl;
+            cout << "f2 = " << m_f2->write("x") << endl;
+            cout << "d1 = " << d1 << " " << d1->write("x") << endl;
+            cout << "d3 = " << d3->write("x") << endl;
+            cout << "d2 = " << d2->write("x") << endl;
+            cout << "function = \'" + write("x") + "\'\n";
+            cout << "derivative = \'" + p->write("x") + "\'\n";
+#endif 
+            return *p;
         }
         virtual std::string write(std::string arg) const;
         virtual int order() const { return 2; }