be clearer that lsb/msb look for 1 bits

S32-setting-library/Numeric.pod

@@ -19,7 +19,7 @@ DRAFT: Synopsis 32: Setting Library - Numeric
 
     Created: 19 Mar 2009 extracted from S29-functions.pod
 
-    Last Modified: 29 Sept 2013
+    Last Modified: 29 May 2013
     Version: 17
 
 The document is a draft.
@@ -496,13 +496,16 @@ Returns False if C<$x> is known not to be a prime.
 
  multi method lsb ( Int $x: ) is export
 
-Returns the least significant bit position, where 0 is where the 1 bit is, 1 is where the 2 bit is, and so on.
+Returns the least significant bit position containing a 1 bit, counting
+bit positions from least significant to most significant.  (In other
+words, it's the base 2 logarithm of number represented by that 1 bit.)
 
 =item msb
 
  multi method msb ( Int $x: ) is export
 
-Returns the most significant bit position, that is, the base 2 log of the top bit.
+Returns the most significant bit position containing a 1 bit, that is,
+the base 2 logarithm of the top 1 bit.
 
 =back