mt1955 writes: "This would be really cool (pun intended) Using a difference engine to run cars with liquid nitrogen. IO9 reports: With all the hype surrounding electric cars and hydrogen-powered fuel-cells, it's easy to think hydrogen is the future of automobiles. But as people start developing and popularizing these enviro-friendly cars, some problems are becoming apparent. And meanwhile, there's a new kid on the block that is threatening to overturn our assumptions about electric cars — and its name is liquid nitrogen. What do you think slashdotters? Could a liquid nitrogen difference engine be the next big thing since the horseless carriage?"