TV’s “Alfred Hitchcock Presents” premiered on this day in 1955. For years the famed director himself appeared at the start of each show to set up his mysteries. One mystery Hitchcock never had to face was “why must gardeners use gas leaf blowers at 7 a.m.”? If Hitchcock had his way they’d surely have been history before the end of act one. Instead, scientists have stepped up to save the day with a battery-powered electric leaf blower that creates a 190-mile-per-hour air stream, but at only 60 decibels, compared to 75 decibels for gas models. It’s compact and weighs only 10 to 20 pounds depending on the size battery used. And that’s the On The House tip for today.