Early Manufacture of Sulphuric Acid. MESSRS. EDITORS :—In the SCIEKTIFIC AMERICAK, of October 16th, on page 246, I find an article treating on the subject of sulphuric acid, showing its great utility and the manner of its production. Ihere take the liberty to place before your readers, some facts relative to the first manufacture of sulphuric acid, or oil of vitriol, in America, and give (as well as my memory serves me) a correct description of the apparatus used, tho mode of its manufacture, by whom manufactured, and where made. Previously to the year 1810, but .little of the article was used in this country ; and that little was imported from other countries, and until that time, its manufacture was unknown in America as an article of commerce. In tho year 1810, Mr. H. Baldwin, a native of the town of Woodbridge, in the county of New Haven, Cennecticut, a graduate of Yale College (assisted financially by Mr. Lott Newell, a fellow grad uate), who conceived the idea of erecting a laboratory for the purpose of making experiments in chemistry, and for the further purpose of manufacturing sulphuric acid, or oil of vitriol, for the market. He procured for that purpose a building which belonged to my father, situated on the post road leading from New Haven to Humphreysville, it being seven miles from New Haven, and three from Humphreysville. In this building he established his laboratory which was arranged m two rooms, each 9 by 18 feet, one of which was elevated about six feet above the other and lined with heavy gh eet lead, and having a door about three feet square in each end, which closed perfectly air tight. In the middle of this room upon a large stone was a kettle that would hold from fifteen to twenty gallons. The kettle was filled with brimstone and a small quantity of saltpeter, which he had previously ground together in an old fashioned wo-den ring and wheel mill made for grinding apples for cider. The floor of this room was covered about four inches deep with waier. The brim stone in the kettle was set on fira by means of a stone or bit of iron which was heated sufciently hot to ignite it when thrown into it. The doors were then closed and remained shut twenty-four hours, at which time they were opened, the kettle refilled, and again set on fire. This operation was repeated f "r six days in succession, during which time th e water had become as sour as ordinary vinegar by the nitrous substance deposited from the smoke. This water was then drawn off and boiled down in glass retorts (buried in a sand bath), until its weight indicated it to be of sufficient strength. The furnace was in the other room situated on the ground and was constructed with two parallel walls of brick about two and one half feet high, and about eight feet in length, with a grate, and ash pit at one end, and a chimney rising from the other end. The top waB a corrugated sheet of metal on which was sand of sufficient depth to cover the retorts, wliich contained the water. Each retort contained about two gallons, and the number used at one time did not exceed twelve. In several instances his retorts were burnt and he came near losing his life from the fumes produced by the boiling vitriol. With this apparatus he continued his experiments, and subsequently manufactured it for two years, retailing a large portion of his product to the country cloth dressers, at 83 cents per lb.; the residue was sent to market in New Haven and New York, where it attracted the attention of a business firm, one of whom (a Mr. Morrison) came to Woodbridge and arranged with Mr. Baldwin to remove his laboratory to New York, and there, with the aid of proffered capita], to erect a chemical factory on a larger scale. Accordingly his leaden room was stripped of its lining, the sheet of lead being rolled in large rolls, which, with such other portion of his equipage as was movable, were taken by ox teams to Derby, and from thence to New York, where it was again put up for use. The location was in the north-western suburbs of the city, near the banks of the Hudson river. I think the p"!ace was called Greenwich at that time. Mr. Baldwin continued to supcrintent the manufacture of this establishment for several years, nnt.il his health became so impaired that 1 was obliged to retire, when he returned to the home of his childhood wh re he remained until his death. In the above, I have given a brief description of the origin of the chemical factory in New York, and the mode by which the oil of vitriol was first manufactured in this country. Skanea teles, ?. Y. JOEL G NORTHBUP. Tlie Discovery of Oersted Contested. MESSRS. EDITOBS :—In one of the latest numbers of an industrial journal of this city, appears the following passage : 'The real discoverer of the fundamental principle which lies at the base of all the present different systems of telegraphs in use, was Oersted, of Copenhagen. For more than a century a relation had been known to exist between electricity and magnetism, but the nature of this relation remained a profound secret until, in 1819, Oersted discovered what has been called, after him, the law of Oersted, namely, that the magnetic polarity lies at right aDgles around the electric current, and vice versa; the direct result is that any compass needle will place itself across the electric current, and the experiment illustrating this is called the experiment of Oersted. If ever a discovery was important in its far-reaching results it was this, and in the whole field of human progress there is scarcely another instance in which one single and simple principle bore such rich fruits, not only in regard to useful, practical application, but also in divulging to us some of the hidden mysteries of forces which appear, to lie at the foundation of our very existence as living beings." I should have refrained from quoting these sentences, if they did not truly express the belief of the authors of our text-books on physics and kindred sciences But, this being the case, I cannot but call attention to the fact that the Russian savant, M. Ham-el (vide the Bulletin de l'Acadmie de St. Petersburg, vol. ii. p. 110), nine years ago, proved that the discovery so unanimously ascribed to Oersted, had been made seventeen years earlier —in Slay, 1803—by the Italian physicist Romagnosi ; it having first been published in the Gazette of Trent. Undoubtedly, political, hole-and-corner journals are not the proper depositories for scientific discoveries, and it would rather be surprising if Oersted had searched for anything of this kind in such papers. However, an account of the experiments of Romagnosi was also inserted in ham's Manuel du Galvanisme, and in Aldini's Essai thorique experimental sur la Galvanisme, both of which were published in Paris in 1804. The discovery of Romagnosi must therefore have been known in scientific circles ; besides, Oersted was in Paris in 1802, 1803, ana 1813. He even maintained a lively correspondence with the author of the last-named work. It can hardly be possible, therefore, that the Danish sonant was not acquainted with the facts in question. Of these the first-mentioned treatise states that " Romagnosi, a physicist of Trent, has discovered that the magnetic needle is deflected by the galvanic current." And in the latter, " according to the observations of Romagnosi, a physicist of Trent, the magnetic needle suffers a deflection wher exposed to the electric current." This, neither mora nor less, constitutes Oersted's often-Iraised discovery. With all due respect to this investigator, one cannot but confess that, in relating his own experiments, it would have conferred more praise upon him if he had also mentioned the labors of others. And it is characteristic that the discovery of the Italian scientist is still not recognized, although Can-tu,in a pamphlet published in Milan, in 1835, again called attention to it. We learn from this that the exact sciences have also their dogmas to which they adhere, no matter whether they have been disproved or not ; and, further, we learn that it is not sufficient to make discoveries, but that one must also understand how to present them to the world. Now York city. ADOLPTX OTT. [We publish in another column an account of the discovery above alluded to, and which has been generally attributed to Oersted.—EDS.