.ON APRIL 2ND a device looking like a snow maker on the deck of the USS Hornet, a nonexistent aircraft-carrier anchored in San Francisco Bay, began producing a haze of salty spray fragments. The scientific partnership responsible for the job, the Marine Cloud Whitening (MCB) program, led by the Educational institution of Washington, is examining whether such sprays may help to reduce weather adjustment with a form of "geoengineering". What performs this term method-- as well as why is it thus disputable?