The gradual passing out of existence of Indian slavery, furthermore, was due, in no small measure, to its unsatisfactory character. The leading colonists early made up their minds to this effect. Bienville, in a letter to the Minister of Marine, July 28, 1706, stated that the French colonists earnestly requested negroes to till their lands, for whom they were willing to pay silver, since the colonies found Indian slaves unsatisfactory. He furthermore requested permission for the colonists to transport Indian slaves to the West Indian Islands in exchange for negroes. The fact that the colonists were willing to trade three Indians for two negroes is sufficient proof of the small value of Indians as slaves.[320] Another letter to the home government, in 1717, records the same state of affairs in the colony.[321] Indian slaves were prone to run away, and their use by the French as individual laborers, or their use only in small groups, if worked together, made escape comparatively easy. A letter of Périer to the home government, May 12, 1728, declared that the traffic in Indian slaves and their use in the French colony was contrary to the welfare of the country, since such slaves served but a short time before they escaped back to their own tribes or to neighboring Indians. Moreover, these deserting Indians persuaded the negro slaves to run away with them.[322] A letter from the President of the Navy Board to la Jonquière and Bigot, May 4, 1749, represented that the Indian slaves brought up in the colony by the officers or by the inhabitants, generally left them when they attained a certain age and again became uncivilized; that they were the more dangerous on account of the knowledge which they had acquired of the country, being better able than others to make incursions therein; and that through the habit of keeping these slaves the whites were dissuaded from becoming domestic servants.[323] Among the slaves the boys were not so much to be depended upon as the girls, since they were stubborn, resented more strongly their being held in slavery, and were more inclined to run away. Long’s Journal, 1768–1782, speaking of the western Indians, records: “They are also full of pride and resentment, and will not hesitate to kill their masters in order to gratify their revenge for a supposed injury. The girls are more docile, and assimilate much sooner into the manners of civilization.”[324] It is probable that slaves coming from the Pawnee tribe, and held so largely by the French of Detroit and Canada, were more satisfactory than those coming from other tribes.[325] It has been said that “it would be difficult to find another of the wild tribes of the continent capable of subjection to domestic slavery.”[326] But the Pawnee, like other slaves, ran away.[327]