These two towns were built upon the prosperity of the whale fishery.  When it languished their fortunes sunk, never to rise to their earlier heights, though cotton-spinning came to occupy the attention of the people of New Bedford, while Nantucket found a placid prosperity in entertaining summer boarders.  And even during the years when whales were plentiful, and their oil still in good demand, there came periods of interruption to the trade and poverty to its followers.  The Revolution first closed the seas to American ships for seven long years, and at its close the whalers found their best market—­England—­still shut against them.  Moreover, the high seas during the closing years of the eighteenth and the opening of the nineteenth centuries were not as to-day, when a pirate is as scarce a beast of prey as a highwayman on Hounslow Heath.  The Napoleonic wars had broken down men’s natural sense of order and of right, and the seas swarmed with privateers, who on occasion were ready enough to turn pirates.  Many whalers fell a prey to these marauders, whose operations were rather encouraged than condemned by the European nations.  Both England and France were at this period endeavoring to lure the whalemen from the United Colonies by promise of special concessions in trade, or more effective protection on the high seas than their own weakling governments could assure them.  Some Nantucket whalemen were indeed enticed to the new English whaling town at Dartmouth, near Halifax, or to the French town of Dunkirk.  But the effort to transplant the industry did not succeed, and the years that followed, until the fateful embargo of 1807, were a period of rapid growth for the whale fishery and increasing wealth for those who pursued it.  In the form of its business organization the business of whaling was the purest form of profit-sharing we have ever seen in the United States.  Everybody on the ship, from captain to cabin-boy, was a partner, vitally interested in the success of the voyage.  Each had his “lay”—­that is to say, his proportionate share of the proceeds of the catch.  Obed Macy, in his “History of Nantucket,” says:  “The captain’s lay is generally one-seventeenth part of all obtained; the first officer’s one-twenty-eighth part; the second officer’s, one-forty-fifth; the third officer’s, one-sixtieth; a boat-steerer’s from an eightieth to a hundred-and-twentieth, and a foremast hand’s, from a hundred-and-twentieth to a hundred-and-eighty-fifth each.”  These proportions, of course, varied—­those of the men according to the ruling wages in other branches of the merchant service; those of the officers to correspond with special qualities of efficiency.  All the remainder of the catch went to the owners, who put into the enterprise the ship and outfitted her for a cruise, which usually occupied three years.  Their investment was therefore a heavy one, a suitable vessel of 300-tons burden costing in the neighborhood of $22,000, and her outfit $18,000 to $20,000.