A Mr. Langdon had brought forward a newly invented hydraulic machine, which was supposed to possess the power of raising water to a greater height than had hitherto been considered possible. A company of mechanics and others became interested in this machine, and appointed Mr. Fessenden their agent for the purpose of obtaining a patent in London. He was, likewise, a member of the company. Mr. Fessenden was urged to hasten his departure, in consequence of a report that certain persons had acquired the secret of the invention, and were determined to anticipate the proprietors in securing a patent. Scarcely time was allowed for testing the efficacy of the machine by a few hasty experiments, which, however, appeared satisfactory. Taking passage immediately, Mr. Fessenden arrived in London on the 4th of July, 1801, and waited on Mr. King, then our minister, by whom he was introduced to Mr. Nicholson, a gentleman of eminent scientific reputation. After thoroughly examining the invention, Mr. Nicholson gave an opinion unfavorable to its merits; and the question was soon settled by a letter from one of the Vermont proprietors to Mr. Fessenden, informing him that the apparent advantages of the machine had been found altogether deceptive. In short, Mr. Fessenden had been lured from his profession and country by as empty a bubble as that of the perpetual motion. Yet it is creditable both to his ability and energy, that, laying hold of what was really valuable in Langdon's contrivance; he constructed the model of a machine for raising water from coal-mines, and other great depths, by means of what he termed the "renovated pressure of the atmosphere." On communicating this invention to Mr. Nicholson and other eminent mechanicians, they acknowledged its originality and ingenuity, and thought that, in some situations, it might be useful. But the expenses of a patent in England, the difficulty of obtaining patronage for such a project, and the uncertainty of the result, were obstacles too weighty to be overcome. Mr. Fessenden threw aside the scheme, and, after a two months' residence in London, was preparing to return home, when a new and characteristic adventure arrested him.