Engelhard Posts Flat 3rd-Quarter Results  NEW YORK (Reuters) - Specialty chemicals company Engelhard  Corp. &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=EC.N target=/stocks/quickinfo/fullquote"&gt;EC.N&lt;/A&gt; on Monday posted flat third-quarter results as  higher raw material costs and an unusually severe hurricane  season offset slightly higher sales.