After the profit fall-off that they predicted for 1968's first half failed to materialize, U.S. economists waited for the new 10% income-tax surcharge, which affects corporations as well as individuals, to cut back profits in the third quarter. The year may. turn out to be a lot tougher for economists than for corporations. Instead of a slowdown, a Wall Street Journal survey of 438 early-reporting companies found combined third-quarter earnings up by a robust 13.6% over the same period a year ago. A sampling:
> Oil companies, fueled by record world wide production and strong prices on...