 The first seeding experiment since the Cirrus disaster was attempted on September 16 , 1961 , into Hurricane Esther by NHRP and the United States Navy aircraft . Eight cylinders of silver iodide were dropped into Esther 's eyewall , and winds were recorded as weakening by 10 percent . The next day , more seeding flights were made . This time , the silver iodide did not fall into the eyewall , and no reduction in windspeed was observed . These two results were interpreted as making the experiment a " success " . 
