diff --git a/lib/gibbler/history.rb b/lib/gibbler/history.rb
index 039df3a..49530ee 100644
--- a/lib/gibbler/history.rb
+++ b/lib/gibbler/history.rb
@@ -53,7 +53,7 @@ def gibble_revert
   
 end
 
-class Hash
+class Gibbler::Hash
   def gibble_revert
     raise "No history (#{self.class})" unless has_history?
     @@mutex.synchronize {
@@ -65,7 +65,7 @@ def gibble_revert
   end
 end
 
-class Array
+class Gibbler::Array
   def gibble_revert
     raise "No history (#{self.class})" unless has_history?
     @@mutex.synchronize {
@@ -77,7 +77,7 @@ def gibble_revert
   end
 end
   
-class String
+class Gibbler::String
   def gibble_revert
     raise "No history (#{self.class})" unless has_history?
     @@mutex.synchronize {
diff --git a/tryouts/50_history_tryouts.rb b/tryouts/50_history_tryouts.rb
index f453b93..4ef0f8d 100644
--- a/tryouts/50_history_tryouts.rb
+++ b/tryouts/50_history_tryouts.rb
@@ -117,7 +117,6 @@ class ::String
     a.gibble_revert
   end
   
-  
 end