title: XPath in Nokogiri returning empty array [] whereas I am expecting to have results
body: <p>I am trying to parse XML files using Nokogiri, Ruby and XPath. I usually don't encounter any problem but with the following I can't make any xpath request:</p>
  
  <pre><code>doc = Nokogiri::HTML(open("myfile.xml"))
  doc.("//Meta").count 
  # result ==&gt; 0
  
  doc.xpath("//Meta") 
  # result ==&gt; []
  
  doc.xpath(.).count
  # result =&gt; 1
  </code></pre>
  
  <p>Here is an simplified version of my XML File</p>
  
  <pre><code>&lt;Answer xmlns="test:com.test.search" context="hf%3D10%26target%3Dst0" last="0" estimated="false" nmatches="1" nslices="0" nhits="1" start="0"&gt;
    &lt;time&gt;
      ...
    &lt;/time&gt;
    &lt;promoted&gt;
      ...
    &lt;/promoted&gt;
    &lt;hits&gt;
      &lt;Hit url="http://www.test.com/" source="test" collapsed="false" preferred="false" score="1254772" sort="0" mask="272" contentFp="4294967295" did="1287" slice="1"&gt;
        &lt;groups&gt;
          ...
        &lt;/groups&gt;
        &lt;metas&gt;
          &lt;Meta name="enligne"&gt;
            &lt;MetaString name="value"&gt;
            &lt;/MetaString&gt;
          &lt;/Meta&gt;
  
          &lt;Meta name="language"&gt;
            &lt;MetaString name="value"&gt;
              fr
            &lt;/MetaString&gt;
          &lt;/Meta&gt;
          &lt;Meta name="text"&gt;
            &lt;MetaText name="value"&gt;
              &lt;TextSeg highlighted="false" highlightClass="0"&gt;
                La
              &lt;/TextSeg&gt;
            &lt;/MetaText&gt;
          &lt;/Meta&gt;
        &lt;/metas&gt;
      &lt;/Hit&gt;
    &lt;/hits&gt;
    &lt;keywords&gt;
      ...
    &lt;/keywords&gt;
    &lt;groups&gt;
      ...
    &lt;/groups&gt;
  </code></pre>
  
  <p></p>
  
  <p>How can I get all children of <code>&lt;Hit&gt;</code> from this XML? </p>