That's only the case if Congress adjourns within ten days after the bill is passed. If Congress is still in session at the ten day point and the President has not signed the bill, it becomes law. The former is called a pocket veto and there's a pretty lively history of its use, going back to Lincoln.
Thanks for clarifying
I do know one tidbit about Johnson who became President by default when Lincoln was murdered. He had the most vetoes in history if I am not mistaken.
"Damn the torpedoes, full speed ahead!" -Admiral Farragut @ Battle of Mobile Bay 05AUG1864