Mr. Chickering did not continue long in business with Mr. Stewart. The latter withdrew in a few years, and Mr. Chickering carried on the business alone. In 1830 he formed a partnership with Captain John Mackay, a retired ship-merchant. In the new firm Captain Mackay took charge of the finances and the office business, while Mr. Chickering devoted himself entirely to the mechanical department. The operations of the new house were very successful. The improvements made by Mr. Chickering from the first created a demand for their instruments which was sometimes so great that it was difficult to supply it. This demand continued to increase, until the house was perfectly easy as to money matters, and able to enlarge its facilities very greatly. It was Mr. Chickering's design that each separate instrument should be an improvement upon those which had preceded it, and he was careful that this plan should not miscarry. In a few years the firm was enabled to import the foreign materials needed, by the cargo, thus saving the profit which they had hitherto been compelled to pay the importer. Besides this saving, they were enabled to keep on hand a large stock of the woods used in the instrument, and thus it was allowed to become more thoroughly seasoned than that which they had been compelled to purchase, from time to time, in small quantities. In 1841, Captain Mackay sailed from Boston for South America, for the purpose of obtaining a supply of the woods needed by the firm; but he never returned, and as no tidings of him or his ship were ever received, it is supposed that the vessel went down at sea with all on board. Mr. Chickering now decided to continue the business without a partner. His friends supposed that in assuming the management of the concern, in addition to the direction of the mechanical department, and the constant mental labor to which he subjected himself in his efforts to improve the piano, he was undertaking more than he was capable of performing. They feared his health would break down under it. Besides, it was generally believed that, in spite of Mr. Chickering's undoubted skill in his own department, he was not much of a business man. He was confident of his own ability, however, and did not hesitate to assume the new responsibility.