Sentence:  It is the uncertainty of rainfall in southern California that doubtless makes this region attractive to the <WSD>rainmaker</WSD>. ... An examination into the methods of the <WSD>rainmaker</WSD> shows a disregard of physical laws, and a review of the history of rainmaking affords no proof of his success. By far the most important feature of his work consists in playing upon the credulity of mankind. 
Meaning of the word marked with <WSD> tags:  Someone or something that causes or attempts to cause rain to fall.