In the Story of Corn and Tobacco we touch the superstitions about rain, the most desired thing in the desert. The mahkais used tobacco in their incantations, both for curing sickness and for making rain. It would appear that the Piman mind confused clouds of smoke and clouds of vapor, and because tobacco made clouds it was probably supposed to be potent in begetting rain. The Pimas told me that the Doctor's Square Stone was used in the incantations for rain, and there appears to have been a connection in Piman thought between feathers and clouds, and therefore between feathers and rain, and it will be noticed that when Geeheesop went to get Tobacco's help in making rain he took feathers and both kinds of Doctor-stone.
This story seems to profess to give the origin of tobacco, giant cactus and of tiswin.