When I was a kid in Kansas in the 50s, all we had was a 'water cooler'. It was a metal box with a mesh screen inside where a layer of shredded wood they called 'excelsior' was wrapped. At the top of the unit was a trough where a garden hose was attached and turned to just a trickle. A squirrel cage fan blew slightly cooled, moist air into the house. However, it was only really helpful when you stood reasonably close it it. I remember going with my father to buy a new mat after a couple of years.

Our old 37 Chevvy had a similar gadget that hung on the car window. You'd regularly stop and add some water to the reservoir.

(I have tried a commercial version of the dampened neck wrap. It actually helps.)