As shells are shot out of cannons across the country, millions of pounds of fireworks will be blown open into the sky tonight. But just what's behind those rockets' red glares, what's inside those ...

"We just last month finished altering our tables," says Lisabeth Hoffman. "And now. . . " And now? Scientists, rejoice. Hoffman is a chemist who works for Sargent-Welch, a 150-year-old company that ...