diff --git a/Doc/Manual/D.html b/Doc/Manual/D.html
index dbc505d1e..1db6569a5 100644
--- a/Doc/Manual/D.html
+++ b/Doc/Manual/D.html
@@ -143,15 +143,15 @@
 <p>The full chain of type conversions when a director callback is invoked looks like this:</p>
 
  <div class="diagram"><pre>      type CPPClass::method(type a)
-        ↑                     ↓
+        &uarr;                     &darr;
    &lt;directorout&gt;         &lt;directorin&gt;
-        ↑                     ↓
+        &uarr;                     &darr;
      ctype methodCallback(ctype a)    C++
  ::::::::::::::::::::::::::::::::::::::::::
      imtype methodCallback(imtype a)    D
-        ↑                     ↓
+        &uarr;                     &darr;
   &lt;ddirectorout&gt;       &lt;ddirectorin&gt;
-        ↑                     ↓
+        &uarr;                     &darr;
       dtype DClass.method(dtype a)</pre></div>