[5] One of the reasons which induced Kennedy thus early to begin the business of mule-spinning has been related as follows. While employed as apprentice at Chowbent, he happened to sleep over the master's apartment; and late one evening, on the latter returning from market, his wife asked his success. "I've sold the eightys," said he, "at a guinea a pound." "What," exclaimed the mistress, in a loud voice, "sold the eightys for ONLY a guinea a pound! I never heard of such a thing." The apprentice could not help overhearing the remark, and it set him a-thinking. He knew the price of cotton and the price of labour, and concluded there must be a very large margin of profit. So soon as he was out of his time, therefore, he determined that he should become a cotton spinner. [6] The subject will be found fully treated in Mr. Fairbairn's own work, A Treatise on Mills and Mill-Work, embodying the results of his large experience. [7] Lives of the Engineers, vol. iii. 416-40. See also An Account of the Construction of the Britannia and Conway Tubular Bridges. By William Fairbairn, C.E. 1849. [8] Useful Information for Engineers, 2nd series, 225. The mere list of Mr. Fairbairn's writings would occupy considerable space; for, notwithstanding his great labours as an engineer, he has also been an industrious writer. His papers on Iron, read at different times before the British Association, the Royal Society, and the Literary and Philosophical Institution of Manchester, are of great value. The treatise on "Iron" in the Encyclopaedia Britannica is from his pen, and he has contributed a highly interesting paper to Dr. Scoffern's Useful Metals and their Alloys on the Application of Iron to the purposes of Ordnance, Machinery, Bridges, and House and Ship Building. Another valuable but less-known contribution to Iron literature is his Report on Machinery in General, published in the Reports on the Paris Universal Exhibition of 1855. The experiments conducted by Mr. Fairbairn for the purpose of proving the excellent properties of iron for shipbuilding--the account of which was published in the Trans actions of the Royal Society eventually led to his further experiments to determine the strength and form of the Britannia and Conway Tubular Bridges, plate-girders, and other constructions, the result of which was to establish quite a new era in the history of bridge as well as ship building. [9] House of Commons Debate, 7th July, 1862.