diff --git a/Cantera/python/tutorial/tut2.py b/Cantera/python/tutorial/tut2.py
index 68038cb83..5bd811fb8 100755
--- a/Cantera/python/tutorial/tut2.py
+++ b/Cantera/python/tutorial/tut2.py
@@ -1,12 +1,15 @@
 ####################################################################
-#
-#    Tutorial 2: Using your own reaction mechanism files
-#
+print """
+
+    Tutorial 2: Using your own reaction mechanism files
+
+"""
 ####################################################################
+from time import clock
 
 # You can build a gas mixture object by importing element, species,
 # and reaction definitions from input files in the format described in
-# the document "Defining Phases and Interfaces"). A set of input files
+# the document "Defining Phases and Interfaces". A set of input files
 # in this format is contained in the data folder. 
 
 # Many existing reaction mechanism files are in "CK format," by
@@ -21,32 +24,53 @@
 # Cantera format.
 
 from Cantera import *
-gas1 = IdealGasMix('gri30.cti')
+t0 = clock()
+gas1 = importPhase('gri30.cti')
+print 'time to create gas1 = ',clock() - t0 
 
 # This statement creates a mixture that implements GRI-Mech 3.0, much
 # like function GRI30 does. File 'gri30.cti' is in the 'data'
-# directory. Under Windows, this directory is in
-# C:\Program Files\Common Files\Cantera.
+# directory. Under Windows, this directory is in C:\Program
+# Files\Common Files\Cantera and/or C:\CANTERA\DATA. On most other
+# platforms, it is usually in /usr/local/cantera/data.
 
 # A Cantera input file may contain more than one phase specification, or may
 # contain specifications of interfaces (surfaces).
 
 # Use importPhase to import a phase:
+t0 = clock()
 gas2 = importPhase('diamond.cti', 'gas')        # a gas
+print 'time to create gas2 = ',clock() - t0
+
+t0 = clock()
 diamond = importPhase('diamond.cti','diamond')  # bulk diamond
+print 'time to create diamond = ',clock() - t0
 
 # Use importInterface to import a surface:
+t0 = clock()
 diamonnd_surf = importInterface('diamond.cti','diamond_100',
                                 phases = [gas2, diamond])
-# Note that the bulk (i.e., 3D) phases that participate in the surface reactions
-# must also be passed as arguments to importInterface.
+print 'time to create diamond_surf = ',clock() - t0
+
+# Note that the bulk (i.e., 3D) phases that participate in the surface
+# reactions must also be passed as arguments to importInterface.
+
+# Multiple phases defined in the same input file can be imported with
+# one statement:
+t0 = clock()
+[gas3, diamond2] = importPhases('diamond.cti', ['gas','diamond'])
+print 'time to create both gas3 and diamond2 = ',clock() - t0
+
+# Note that importing from a file is much faster the second time. This
+# is because the file is only read and converted to XML once. The XML
+# tree is kept in memory once it is read in case it is needed later.
 
 # How does Cantera find input files like diamond.cti?  Cantera always
 # looks in the local directory first. If it is not there, Cantera
 # looks for it on its search path. It looks for it in the data
 # directory specified when Cantera was built (by default this is
 # /usr/local/cantera/data on unix systems). If you define environment
-# variable CANTERA_DATA_DIR, it will also look there, or else you can
+# variable CANTERA_DATA, it will also look there, or else you can
 # call function addDirectory to add a directory to the search path.
 
 # Warning: when Cantera reads a .cti input file, wherever it is
@@ -56,5 +80,13 @@ diamonnd_surf = importInterface('diamond.cti','diamond_100',
 # you can use it instead of the .cti file, which will result in
 # somewhat faster startup.
 
+gas4 = IdealGasMix('gri30.xml')
+# Note that the function 'IdealGasMix' simply calls 'importPhase', and
+# checks that the phase represents an ideal gas mixture
+
+# Interfaces can be imported from XML files too.
+diamonnd_surf2 = importInterface('diamond.xml','diamond_100',
+                                 phases = [gas2, diamond])
+
 
 
diff --git a/Cantera/python/tutorial/tut3.py b/Cantera/python/tutorial/tut3.py
index 05635db20..b6aa5d57d 100644
--- a/Cantera/python/tutorial/tut3.py
+++ b/Cantera/python/tutorial/tut3.py
@@ -1,7 +1,9 @@
 ######################################################
-#
-#  Getting Help
-#
+print """
+
+  Tutorial 3: Getting Help
+
+"""
 ######################################################
 
 # Python has a built-in help facility. To get help on any class or
diff --git a/Cantera/python/tutorial/tut4.py b/Cantera/python/tutorial/tut4.py
index 6af70cf7a..fc873eb15 100755
--- a/Cantera/python/tutorial/tut4.py
+++ b/Cantera/python/tutorial/tut4.py
@@ -1,7 +1,9 @@
 #################################################################
-#
-#   Tutorial 4:   Chemical Equilibrium
-#
+print """
+
+   Tutorial 4:   Chemical Equilibrium
+
+"""
 #################################################################
 
 # To set a gas mixture to a state of chemical equilibrium, use the
@@ -9,15 +11,15 @@
 #
 from Cantera import *
 g = GRI30()
-set(g,T=300.0,P=OneAtm,X='CH4:0.95,O2:2,N2:7.52')
+g.set(T = 300.0, P = OneAtm, X = 'CH4:0.95,O2:2,N2:7.52')
 g.equilibrate('TP')
 
 # The above statement sets the state of object 'g' to the state of
 # chemical equilibrium holding temperature and pressure
-# fixed. Alternatively, the specific enthalpy and pressure can be
-# held fixed:
+# fixed. Alternatively, the specific enthalpy and pressure can be held
+# fixed:
 
-set(g,T=300.0,P=OneAtm,X='CH4:0.95,O2:2,N2:7.52')
+g.set(T = 300.0, P = OneAtm, X = 'CH4:0.95,O2:2,N2:7.52')
 g.equilibrate('HP')
 
 # Other options are
@@ -25,15 +27,15 @@ g.equilibrate('HP')
 #     'SV'   fixed specific entropy and specific volume
 #     'SP'   fixed specific entropy and pressure
 
-set(g,T=300.0,P=OneAtm,X='CH4:0.95,O2:2,N2:7.52')
+g.set(T = 300.0, P = OneAtm, X = 'CH4:0.95,O2:2,N2:7.52')
 g.equilibrate('UV')
 print g
 
-set(g,T=300.0,P=OneAtm,X='CH4:0.95,O2:2,N2:7.52')
+g.set(T = 300.0, P = OneAtm, X = 'CH4:0.95,O2:2,N2:7.52')
 g.equilibrate('SV')
 print g
 
-set(g,T=300.0,P=OneAtm,X='CH4:0.95,O2:2,N2:7.52')
+g.set(T = 300.0, P = OneAtm, X = 'CH4:0.95,O2:2,N2:7.52')
 g.equilibrate('SP')
 print g
 
@@ -42,15 +44,17 @@ print g
 # progress of all reversible reactions are zero.
 
 # Here is the code to do this:
-set(g,T=300.0,P=OneAtm,X='CH4:0.95,O2:2,N2:7.52')
+g.set(T = 300.0, P = OneAtm, X = 'CH4:0.95,O2:2,N2:7.52')
 g.equilibrate('HP')
 
 rf = g.fwdRatesOfProgress()
 rr = g.revRatesOfProgress()
 for i in range(g.nReactions()):
    if g.isReversible(i) and rf[i] <> 0.0:
-       print ' %4i   %10.4g   %10.4g   %10.4g  ' % (i, rf[i], rr[i], (rf[i] - rr[i])/rf[i])
-
+       print ' %4i  %10.4g  ' % (i, (rf[i] - rr[i])/rf[i])
+# If the magnitudes of the numbers in this list are all very small,
+# then each reversible reaction is very nearly equilibrated, which
+# only occurs if the gas is in chemical equilibrium.
 
 # You might be wondering how 'equilibrate' works. (Then again, you might
 # not, in which case you can go on to the next tutorial now.)  Method