After operating the lead mine for five years, Dacosta's company failed, and "Mill Grove" again passed into other hands; it was finally sold to Samuel Wetherill in 1813.[146] If our inferences are correct, the mortgages by which the Audubon and Rozier interests were protected were repeatedly transferred, and the first considerable amount of ready money that had appeared in the entire series of transactions was furnished by Mr. Wetherill. It is doubtful if Jean Audubon ever received any returns from his American farm after the advent of Dacosta in 1803. The ultimate failure of the lead mine was assuredly not the fault of this exploiter, but his dubious methods of accounting and probable failure to keep his contracts no doubt led the naturalist to denounce him as a swindler. It may be recalled that in their "Articles of Association" Audubon and Rozier had agreed that the house at "Mill Grove" should be "an object separate from all business, in order that we may control this property as long as we desire," but the conditional sale to Dacosta apparently included the farmhouse as well as the land. Many of Audubon's references to "Mill Grove" were apparently wide of the mark, but viewed in the light which we have endeavored to shed upon this involved affair, they would be in harmony with the essential truth; in writing to the elder Rozier, who became a partner in the enterprise, there was no motive which could have led him to depart from it.[147] We will now return to the story of Audubon's life in New York. While he was supposed to be learning the exporting business with Benjamin Bakewell, his heart was in the woods and fields, and every hour that could be snatched from the counting-room found him in the pursuit of birds or drawing their portraits. He used the pencil and black crayon point combined with pastels, and while much of his artistic work at this time was hastily done, he was capable of producing excellent likenesses. A very delicate drawing of the Wood Thrush, signed with his initials, and dated at "Mill Grove, Pennsylvania, 14 _aout_, 1806," is numbered 209, showing that his collection of American birds was already extensive, even if it did not include many that were well known. In the winter of 1806-7, while in New York, Audubon paid most attention to the waterfowl, frequently visiting the shore and the markets for his subjects. The sketches which he then made were all in full size, and, as an evidence of the rapidity with which he worked, it may be noticed that he would often complete two or more large drawings of ducks on the same day. New York at this time was a city of about 75,000 people; Audubon said that by walking briskly he could pass from one end to the other in a few minutes.