Carl Bialik writes "The Wall Street Journal is reporting that 'Using technologies developed for the space program, the U.S. Army is conducting an experiment that could convert the exhaust pipes of military vehicles into water fountains.' The idea is meant to help alleviate the logistical challenges presented by two essential army liquids: water and diesel fuel. A soldier in the desert needs about 20 gallons of water a day, for all purposes; 'Water gets to the front in vulnerable, slow-moving truck convoys that require armed escorts, or it is pumped from local rivers, lakes or ponds and purified by heavy-duty filters.' And maybe, in the future, it will also be extracted from diesel exhaust. The president of a company that developed the test technology tells the WSJ: 'This is one of those things where, when you first hear about it, you think the scientists have gone out of their minds. But once you taste the water, you realize the potential.'"