A locomotive dispatched irom Laporte, Ind , to Chicago, for physicians to attend Robert Doxtader, Esq, President of the road, who died at that place of appoplexy, ran the entire distance and back, in one hour and tor-ty minutes. The distance is 58 miles each way, making a speed of 116 miles in 100 minutes. This is fully up, if not superior to the speed daily attained on the English Great Western Railroad between Paddington and London.