When using a swamp cooler can you use a rheostat to control the motor speed?

A: A swamp cooler uses water flow to control temperatures as the water flow increases the transfer function increases. So yes it will effect the temperature. but for humans at the same time more water in the air will effect our perspiration and cooling in effect basically it will reach an equilibrium whereby more water will not cool us any further. A 70 degrees and 100 % humidity is hotter then 85 degrees dry heat