Switch On Front
Turns on the electrically lit pilot light, you turned it on at the start of laundry day and turned it off when you were done to save gas.
I think they were also reducing wear on the ignition system by not making it go through the ignition sequence every time the dryer called for heat.
They only did this on their first two model gas dryers, this dryer was their 2nd gas dryer model, it was built from about 1950-52.
John L.