A farmer boarding a city-bound train found himself next to a man who was acting strangely-- glancing quickly out of the window, muttering to himself, glancing again. Curiousity overpowered him, and he asked the stranger if anything were the matter. "No, indeed," was the answer. "I'm a lightning calculator, you see. Just for fun, I count the number of cars parked on the street as we pass towns, the number of people in the stations, the number of trees in a grove-- I never make a mistake." "Wonder full," said the farmer. "In a few moments we're going to pass my pasture. I know the exact number of cows grazing there-- would you care ...?" The lightning calculator was delighted to be put to the test. As the train flashed past he gave one glance at the cows and announced "157." "Amazing," exclaimed the farmer. "How did you do it?" "It's easy," replied the calculator. "All I did was count the cow's teats and divide by four."