The bounties on scalps and prisoners were another occasion of royal complaint. Twenty crowns had been offered for each male white prisoner, ten crowns for each female, and ten crowns for each scalp, whether Indian or English. [15] The bounty on prisoners produced an excellent result, since instead of killing them the Indian allies learned to bring them to Quebec. If children, they were placed in the convents; and, if adults, they were distributed to labor among the settlers. Thus, though the royal letters show that the measure was one of policy, it acted in the interest of humanity. It was not so with the bounty on scalps. The Abenaki, Huron, and Iroquois converts brought in many of them; but grave doubts arose whether they all came from the heads of enemies. [16] The scalp of a Frenchman was not distinguishable from the scalp of an Englishman, and could be had with less trouble. Partly for this reason, and partly out of economy, the king gave it as his belief that a bounty of one crown was enough; though the governor and the intendant united in declaring that the scalps of the whole Iroquois confederacy would be a good bargain for his Majesty at ten crowns apiece. [17] [15] Champigny au Ministre, 21 Sept., 1692. [16] Relation de 1682-1712. [17] Mémoire du Roy aux Sieurs Frontenac et Champigny, 1693; Frontenac et Champigny au Ministre, 4 Nov., 1693. The bounty on prisoners was reduced in the same proportion, showing that economy was the chief object of the change. The river Ottawa was the main artery of Canada, and to stop it was to stop the flow of her life blood. The Iroquois knew this; and their constant effort was to close it so completely that the annual supply of beaver skins would be prevented from passing, and the colony be compelled to live on credit. It was their habit to spend the latter part of the winter in hunting among the forests between the Ottawa and the upper St. Lawrence, and then, when the ice broke up, to move in large bands to the banks of the former stream, and lie in ambush at the Chaudière, the Long Saut, or other favorable points, to waylay the passing canoes. On the other hand, it was the constant effort of Frontenac to drive them off and keep the river open; an almost impossible task. Many conflicts, great and small, took place with various results; but, in spite of every effort, the Iroquois blockade was maintained more than two years. The story of one of the expeditions made by the French in this quarter will show the hardship of the service, and the moral and physical vigor which it demanded.