Southern Co. Quarterly Profit Rises  NEW YORK (Reuters) - Southern Co. &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=SO.N target=/stocks/quickinfo/fullquote"&gt;SO.N&lt;/A&gt;, which supplies  power to the U.S. Southeast, said Thursday its third-quarter  earnings rose slightly, as increased energy use in the  industrial sector and more customers outweighed mild weather  and hurricane damage.