Troy, and exhibited it at the Rensselaer Institute. From thence he proceeded to Princeton, New Jersey, and submitted it to the examination of Professor Henry, where he first learned that Professor Henry had procured a vibratory motion from magnets. He next visited Philadelphia, and exhibited his machine to Professors Bache, Hamilton, and others, at the Franklin Institute. Professors Henry and Bache both gave Mr. Davenport flattering certificates as to the originality and importance of his invention. He then proceeded to Washington, and deposited his specification in the patent office. After his return from Washington he went to Springfield, Massachusetts, where, with the assistance of some mechanics, he built a small circular rail-way, on which he placed an Electro-Magnetic Engine. With this apparatus he proceeded to Boston in December, 1835, and exhibited the same two weeks at the Marlboro' Hotel. Notwithstanding it was favourably noticed in some of the Boston Papers, he met with no offers of assistance towards a farther prosecution of his plan. During the whole period Mr. Davenport employed his time, when not travelling, in experiments on this science. In the summer of 1836 he visited Saratoga Springs, where he exhibited his machine two weeks. Here he became acquainted with Mr. Ransom Cook, a mechanic of that place; who being the owner of a fine shop, with excellent machinery, moved by steam power, more readily appreciated the value of Mr. Davenport's invention, than could have been expected from many others. Struck with its value and importance on his first examination, Mr. Cook offered, from benevolent motives alone, to assist Mr. Davenport in bringing it into public use. As the patent had not yet been obtained, Messrs. Davenport and Cook commenced building a model to deposite in the patent office. As the work progressed, Mr. Cook made an important alteration in the arrangement of the machine, and became more and more enamoured with the invention. Every well established fact, and every new discovery in this interesting science, served to confirm Mr. Cook in his first favourable opinion, and increase his confidence in the ultimate successful application of this power. On Mr. Davenport's offer of an interest in the invention, Mr. Cook suspended an active business at home, and embarked in the enterprise with all his energies. Through the last fall, and part of the winter, Messrs. Davenport and Cook spent their time in active experiments on this subject, and employed several hands in building models for their own use, as well as various sets to be sent to the different countries of Europe. They came to this city with their models in February last. On ascertaining the expense of procuring patents in Europe, and the probable cost of building a large power, in order to give the most convincing proof of the value of this discovery, the proprietors found the amount too heavy to be met by themselves. The panic, as it is termed, had also commenced, and the miracle was not to be expected of meeting with an individual who had more money than he wanted for his own immediate use. Under these circumstances, the proprietors, with the advice of their friends, threw the invention into a Joint Stock Association, consisting of three thousand Shares. By the Articles of Association, dated March 3, 1837, they deliver to Edwin Williams, Secretary of the American Institute, a portion of the stock, with which he is to raise funds, to "build models and machinery for giving to this invention its greatest possible value, for the benefit of the Stock Holders, (the constructions so made, to belong to the Association ;) also, for securing the exclusive use of said invention in Europe, for the benefit of the Association." Sufficient Stock has already been sold to prosecute improvements thus far, and to secure the patent in England, Ireland, Scotland, and the British dependances; which letters passed the King's seal a short time previous to his death. Preliminary arrangements have also been made for securing the patent in the remaining countries of Europe. It is desirable immediately to sell sufficient stock to refund the expenses incurred in securing the patent for the remainder of Europe, and to enable the proprietors to build a large working power; which, as soon as put in operation, will no doubt advance the stock several hundred per cent. Since the proprietors have been in this city they have been engaged in a series of rapid improvements in the power of this engine. So great have been the advances since the invention, that by the accurate experiment of lifting weights with the machine, it is found that the power has been increased five hundred and twenty-eight fold: that is, a single pound of iron wrought into a machine on the present arrangement, gives as much power as could have been obtained from a machine weighing five hundred and twenty-eight pounds, if made according to the first invention. Notwithstanding this astonishing increase of power, and the prospect that it may yet be increased as much more, no departure from the principle of the original invention has been or can be made. That principle was the production of rotary motion by repeated changes of magnetic poles; this it is which is secured by patent; and no peculiarity of arrangement, or modification of the magnets, can be made to move without adopting the essence of the first invention. Hence no patent was probably ever obtained, which in its nature was more inviolable than this. It has been often remarked that this machine carries with it the test of truth: that is, that the better its principles are understood; the more they are investigated, the more highly it is prized. It has been steadily growing into favour under the scrutiny of the best judges in the country, and has never failed to make a friend of every individual who well understands it. Error and imposition, on the contrary, always wither beneath investigation. It is not to be expected that those whose interests and fortunes are embarked in the use of steam power, should feel very anxious for the success of this machine. Yet even in this class there are several whose benevolence desires the good of all, and who are among its warmest supporters. Among other illustrations, the proprietors have built five different grades of machines, varying in size and weight. From a principle in the course of the magnetic currents, and the improved energy of the magnets by induction, it is found that the power of the machines increase in a greater ratio than they are increased in weight. As this power is procured by the action of the galvanic fluid upon iron; as both iron and the galvanic fluid can be obtained in the greatest abundance; no reason can be assigned why any amount of power necessary for human purposes may not be brought into subserviency on this principle. PROFESSOR SILLIMAN'S REMARKS. FROM SILLIMAN'S AMERICAN JOURNAL OF SCIENCE AND ARTS, Notice of the Electro-Magnetic Machine of Mr. Thomas Many years have passed since motion was first produced by galvanic power. The dry columns of De Luc and Zamboni caused the vibration of delicate pendulums and the ringing of small bells, for long periods of time, even several years, without intermission. In 1819-20, Professor Oersted, of Copenhagen, discovered that magnetism was evolved between the poles of a galvanic battery. Professor Sweigger of Halle, Germany, by his galvanic multiplier, succeeded in rendering the power manifest, when the galvanic battery was nothing more than two small wires, one of copper and the other of zinc, immersed in as much acidulated water as was contained in a wine-glass. The power thus evolved, was made to pass through many convolutions of insulated wire, and was thus augmented so as to deflect the magnetic needle sometimes even 90°. Professor Moll of Utretcht, by winding insulated wire around soft iron, imparted to it prodigious magnetic power, so that a horseshoe bar, thus provided and connected with a galvanic battery would lift over one hundred pounds. About the same time, Mr. Joseph Henry of Albany, now Professor Henry of Princeton College, by a new method of winding the wire, obtained an almost incredible magnetic force, lifting six or seven hundred pounds, with a pint or two of liquid, and a battery of corresponding size; nor did he desist, until a short time after, he lifted thousands of pounds, by a battery |