Sea Travel.

Before the advent of the steam engine in the nineteenth century, mariners had to depend on sail power in order to propel their vessels. In the mid 1700s a ship leaving London could make the transatlantic crossing to Boston in less than eight weeks. The currents, prevailing winds, storms, and skill of the ship's captain factored in the length of a voyage. A typical deep-sea ship had three masts and square sails and displaced between three hundred to four hundred tons. Although faster than ships in the previous century, these vessels averaged only two to five knots (a knot is one nautical mile per hour). In contrast an American destroyer in World War II could travel thirty-seven knots. Life aboard an eighteenth-century ship was anything but ideal, with cramped conditions, salt provisions, occasional tainted water, and the possibility of illnesses, especially dysentery, smallpox...