This is what the most common kind of swamp cooler looked like in the 1950s

 It usually had a hole beneath it through into the roof and there was a fan inside the 3 foot by 3 foot box shape. IN the sides were water running through something like hay or something like that which made the whole house smell a little like a swamp or if rain came down on Hay in a field or something like that. This was the most common way to cool your home in the 1950s before the prices on air conditioning came down to where average people could afford them. You never got cold or cool with a swamp cooler because it was based upon evaporation but at least you tended not to die of the heat with one of these installed in your home or office anywhere in the U.S.