Index: lib/tzinfo/country_timezone.rb
===================================================================
--- lib/tzinfo/country_timezone.rb	(revision 386)
+++ lib/tzinfo/country_timezone.rb	(revision 387)
@@ -1,5 +1,5 @@
 #--
-# Copyright (c) 2006-2010 Philip Ross
+# Copyright (c) 2006-2012 Philip Ross
 # 
 # Permission is hereby granted, free of charge, to any person obtaining a copy
 # of this software and associated documentation files (the "Software"), to deal
@@ -74,10 +74,9 @@
     # current CountryTimezone (has the same identifer, latitude, longitude
     # and description).
     def ==(ct)
-      ct.respond_to?(:identifier) && ct.respond_to?(:latitude) &&
-      ct.respond_to?(:longitude)  && ct.respond_to?(:description) &&
-      identifier == ct.identifier  && latitude == ct.latitude &&
-      longitude == ct.longitude   && description == ct.description         
+      ct.kind_of?(CountryTimezone) &&
+        identifier == ct.identifier  && latitude == ct.latitude &&
+        longitude == ct.longitude   && description == ct.description         
     end
             
     # Returns true if and only if the given CountryTimezone is equal to the
Index: lib/tzinfo/timezone_transition_info.rb
===================================================================
--- lib/tzinfo/timezone_transition_info.rb	(revision 386)
+++ lib/tzinfo/timezone_transition_info.rb	(revision 387)
@@ -1,5 +1,5 @@
 #--
-# Copyright (c) 2006-2010 Philip Ross
+# Copyright (c) 2006-2012 Philip Ross
 # 
 # Permission is hereby granted, free of charge, to any person obtaining a copy
 # of this software and associated documentation files (the "Software"), to deal
@@ -98,7 +98,7 @@
     # considered to be equal by == if offset, previous_offset and at are all 
     # equal.
     def ==(tti)
-      tti.respond_to?(:offset) && tti.respond_to?(:previous_offset) && tti.respond_to?(:at) &&
+      tti.kind_of?(TimezoneTransitionInfo) &&
         offset == tti.offset && previous_offset == tti.previous_offset && at == tti.at
     end
     
@@ -109,8 +109,7 @@
     # which just requires the at times to be equal regardless of how they were
     # originally specified.
     def eql?(tti)
-      tti.respond_to?(:offset) && tti.respond_to?(:previous_offset) &&
-        tti.respond_to?(:numerator_or_time) && tti.respond_to?(:denominator) &&
+      tti.kind_of?(TimezoneTransitionInfo) &&
         offset == tti.offset && previous_offset == tti.previous_offset &&
         numerator_or_time == tti.numerator_or_time && denominator == tti.denominator        
     end
Index: lib/tzinfo/timezone_period.rb
===================================================================
--- lib/tzinfo/timezone_period.rb	(revision 386)
+++ lib/tzinfo/timezone_period.rb	(revision 387)
@@ -1,5 +1,5 @@
 #--
-# Copyright (c) 2005-2010 Philip Ross
+# Copyright (c) 2005-2012 Philip Ross
 # 
 # Permission is hereby granted, free of charge, to any person obtaining a copy
 # of this software and associated documentation files (the "Software"), to deal
@@ -165,17 +165,19 @@
     # Returns true if this TimezonePeriod is equal to p. This compares the 
     # start_transition, end_transition and offset using ==.
     def ==(p)
-      p.respond_to?(:start_transition) && p.respond_to?(:end_transition) &&
-        p.respond_to?(:offset) && start_transition == p.start_transition &&
-        end_transition == p.end_transition && offset == p.offset
+      p.kind_of?(TimezonePeriod) &&
+        start_transition == p.start_transition &&
+        end_transition == p.end_transition &&
+        offset == p.offset
     end
     
     # Returns true if this TimezonePeriods is equal to p. This compares the
     # start_transition, end_transition and offset using eql?
     def eql?(p)
-      p.respond_to?(:start_transition) && p.respond_to?(:end_transition) &&
-        p.respond_to?(:offset) && start_transition.eql?(p.start_transition) &&
-        end_transition.eql?(p.end_transition) && offset.eql?(p.offset)
+      p.kind_of?(TimezonePeriod) &&
+        start_transition.eql?(p.start_transition) &&
+        end_transition.eql?(p.end_transition) &&
+        offset.eql?(p.offset)
     end
     
     # Returns a hash of this TimezonePeriod.
Index: lib/tzinfo/time_or_datetime.rb
===================================================================
--- lib/tzinfo/time_or_datetime.rb	(revision 386)
+++ lib/tzinfo/time_or_datetime.rb	(revision 387)
@@ -1,5 +1,5 @@
 #--
-# Copyright (c) 2006-2010 Philip Ross
+# Copyright (c) 2006-2012 Philip Ross
 # 
 # Permission is hereby granted, free of charge, to any person obtaining a copy
 # of this software and associated documentation files (the "Software"), to deal
@@ -251,7 +251,7 @@
     # constructed with the same type (DateTime, Time or timestamp) as this 
     # TimeOrDateTime.
     def eql?(todt)
-      todt.respond_to?(:to_orig) && to_orig.eql?(todt.to_orig)      
+      todt.kind_of?(TimeOrDateTime) && to_orig.eql?(todt.to_orig)      
     end
     
     # Returns a hash of this TimeOrDateTime.
Index: lib/tzinfo/timezone_offset_info.rb
===================================================================
--- lib/tzinfo/timezone_offset_info.rb	(revision 386)
+++ lib/tzinfo/timezone_offset_info.rb	(revision 387)
@@ -1,5 +1,5 @@
 #--
-# Copyright (c) 2006 Philip Ross
+# Copyright (c) 2006-2012 Philip Ross
 # 
 # Permission is hereby granted, free of charge, to any person obtaining a copy
 # of this software and associated documentation files (the "Software"), to deal
@@ -71,7 +71,7 @@
     # Returns true if and only if toi has the same utc_offset, std_offset
     # and abbreviation as this TimezoneOffsetInfo.
     def ==(toi)
-      toi.respond_to?(:utc_offset) && toi.respond_to?(:std_offset) && toi.respond_to?(:abbreviation) &&
+      toi.kind_of?(TimezoneOffsetInfo) &&
         utc_offset == toi.utc_offset && std_offset == toi.std_offset && abbreviation == toi.abbreviation
     end