Typical Cumulus Cloud (image) Harvard University Caption Lead author Scot Martin and his colleagues expect their ability to isolate relatively "pure" aerosol particles will help elucidate natural aerosol-cloud interactions in the Amazon Basin. Pictured is a typical cumulus cloud; sheets of rain can be seen underneath. Credit Courtesy of Scot Martin, Harvard School of Engineering and Applied Sciences, and colleagues. Usage Restrictions None Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.