Chapter V. DR. CORTLANDT'S HISTORY CONTINUED."In marine transportation we have two methods, one for freight and another for passengers. The old-fashioned deeply immersed ship has not changed radically from the steam and sailing vessels of the last century, except that electricity has superseded all other motive powers. Steamers gradually passed through the five hundred-, six hundred-, and seven hundred-foot-long class, with other dimensions in proportion, till their length exceeded one thousand feet. These were very fast ships, crossing the Atlantic in four and a half days, and were almost as steady as houses, in even the roughest weather.
"Ships at this period of their development had also passed through the twin and triple screw stage to the quadruple, all four together developing one h
