Huh! When you think about it, calling someone an Extension Agent sounds weird--what did/do they extend?
The county agricultural extension agent was an advisor employed by the government to assist people in rural areas with methods of farming and home economics.
I know, I know...you're wondering if there was ever a magazine devoted to advising these advisors, and if there was, could you find it on Google?
About that time, movies were being produced to help tongue-tied agents get the word out, too. So, now there were ads for MOVIES, and PROJECTORS...