From the Report of J. Lawrence Smith, United .States Commissioner to Paris Exposition. Comlmstion of Pyrites Compared idth that of Sulphur.—It is found, in making sulphuric acid from pyrites, that larger chambers are required, and a larger quantity of niter in proportion to the sulphur burnt, than when sulphur is used. This arises from the higher temperature of the vapor from the pyrites, and from the greater quantity of inert gas 1 hat circulates through the apparatus. Too much attention cannot bo given to diminishing the temperature of the gases, but in most works it is neglected ; some, however, pass the gases through a kind of tubular boiler of lead surrounded by water, and thus cool down the vapors before they enter the chamber. Another precaution to be observed is, not to let the lump pyrites exceed the size of an egg, and to free it from fine matter that would clog the openings. There is very convenient machinery devised that will answer this purpose very well. The little loss by the augmentation of inert gas in the chamber where pyrites is used may be diminished by determining, by frequent analyses, the proportion of sulphurous acid introduced into the chamber, a method now slowly growing into use ; tests being made with a solution, titre, of iodine, colored by starch. The gas 13 drawn from the chamber by means of an aspirator, and the water flowing from the aspirator is measured in a graduated vessel, which gives the bulk of the inert gases mixed with the sulphurous acid. This last is absorbed and calculated from the iodine solution through which the gases are made to pass. The mean of these analyses gives nine per cent of sulphurous acid, which, according to the composition of the air and pyrites, ought to be mixed with 79 of n'trogen and 8J of oxygen. This method of testing is well adapted to chambers where nitric acid is used or having nitrification furnaces constructed at the base of the chambers; but this testing can be used for all chambers at the exit, where the gases commonly contain six per cent ot oxygen. It would be well to diminish this quantity, taking care, however, that the oxygen does not disappear entirely, as this is a guarantee against the loss of binoxide of nitrogen, which is not absorbable by the cascade of sulphuric acid of Gay Lussac, when the proprietors of works are prudent enough to use his method of preventing loss of nitrous vapors. Proper manipulation of the pyrites method depends on the nature of the combustion of the pyrites and the regulation of the draft of air. When the furnaces are well constructed with this in view, there can be obtained 120 parts of sulphuric acid for 100 parte of pyrites of 45 per cent of sulphur, thereby utilizing as much as 42 per cent of the sulphur. There is no greater drawback to this method of making sulphuric acid than the admission of too much air. Oxidation of Snlplmrous Acid by Nitrous Acid Vapors.— The compounds of nitrogen and oxygen are used as agents to complete the oxidation of the sulphurous acid by a reaction familiar to chemists. The introduction of the nitrous vapors into the lead chambers is carried on in several ways in Kuhl-mann's large works at Lille, and in other factor! s in France a S'i.all stream of nitric acid is allowed to flow into the nitrification chamber, the size of the stream being regulated so as to furnish the proper proportion where it reacts on the sulphurous acid at a comparatively low temperature. It is a good process, and may be regarded as a more natural process than any other in supplying the nitrous vapors. The acid is allowed to enter into the first chamber in a small stream ; iX Is made to strike on glass gutters, or a stone-ware vessel, in such a manner that the liquid acid is divided into spray. As this falls into the chamber, and comes in contact with the sulphurous acid, it only furnishes the useful nitrous products, there being no formation of protoxide of nitrogen, or nitrogen, as sometimes happens from a rapid action on the niter pans, as when they are carelessly heated red-hot. The operation is very regular, and the economy in nitric acid more than compensates for the expense of first forming the nitric acid. The more common process is by the action of sulphuric acid on nitrate of soda, and passing the vapors thus produced into the lead chambers. The method usually employed in England 13 the best for carrying out this decomposition, it being carried on in one instead of several vessels, and placing the vessel very near the entrance into the lead chambers. The quatitity of nitrate of soda used by the several manufacturers for every 100 parts of sulphur, as stated by G. R. Wright, is For pyrites containing 45 to FOpercent pulphur.............. R'~ per cent. For pvritrs containing 80 to 50 per cent sulphur;............. 12-0 per cent. For pyrites containing 35 average percent sulpliur.......... 12-G? ner cent. For pure sulphur.................................................10-Oper cfnt. Efforts to Produce Sulphuric Acid mtJiout tlte Agency of Nitric Acid or Nitrous Vapor.—Several methods have been proposed, but no one of them has proved successful. Ten-nant Dunlap has approximated to success by a method which is in use, whereby, having once produced the requisite supply of nitrous vapors no more are required except to make up the unavoidable loss. As this process is not familiar to most of our manufacturers, it will here be described, although it has been in successful operation for several years in the gigantic chemical works of C. Tennant Co. Instead of treating nitrate of sofia with sulphuric acid, and employing the nitric thus obtained, a mixture of nitrate of soda and of chloride of sodium is decomposed, which yields, together with sulphate of soda, chlorine gas and nitrous acid. These gases are separated by passing them through concentrated sulphuric acid of not less than 1'75 sp. gr., when the nitrous acid is absorbed, the chlorine being utilized for the production of chloride of lime. The sulphuric solution of nitrous acid is allowed to flow into the chambers, where, by appropriate apparatus, it is brought into contact with water, which disengages the nitrous acid. At the works of Messrs. C. Tennant Co., where this process is in use, they employ Gay Lussac's process for absorbing the nitrous acid from the escaped gases of the chambers, and M. Dunlap's process is used to such an extent as is found needful to provide for the waste of nitrous acid which occurs, notwithstanding the use of Gay Lussac's process. It will thus be seen that the immense quantity of sulphuric acid made by the Messrs. Tennant ".., is formed without anynitrate of soda used specially for obtaining nitrous gas to bo applied to the oxidation of sulphurous acid. Condensation of Nitrous Vapors l/y Gay Imami* Process. —The condensation of the excess of nitrous vapors that escape at the exit of the furnace in sulphuric acid works, by Gay Lussac's process, is very generally employed in France, but to a very small extent ir. England, where eight to ten parts of nitrate of soda are employed to every 100 parts of sulphur burnt. In all well-directed establishments this apparatus should be usad to save the excess of nitrous vapors, and, while its use requires skill and care, it will reduce the quantity of nitrate required to less than two thirds, and the saving will very much more than pay for the increase of expense and attention. This method has been long known, and is fully described in works on industrial chemistry, so that no detail of it need b given in this report. Purification of Stdphuric Add from Arsenic.—The acid is sometimes boiled with a little common salt, and the arsenic goes off as terchloride of arsenic. But probably the most efficient and practical method is that adopted by Kuhlmann in his large acid chambers. The sulphurous acid from the combustion of the pyrites passes into a small chamber of 1,500 cubic feet capacity, that communicates with the furnace by a large leaden pipe forty or fifty feet long, sustained on its inside by iron bands covered with lead. In this way the sulphurous acid is cooled before it reaches the acid chambers, and several condensible products are deposited, among them the arsenious acid. It is also purified by means of sulphide of barium, at Che-s-sy, as it comes from the lead chamber, or by sulphureted hydrogen ; this last is successfully used at Freiberg in the following way : The apparatus used for making the sulphureted hydrogen is composed of two large leaden vessels, placed side by side, and communicating with each other at the bottom. One of the vessels is filled with sulphide of iron and the other with diluted sulphuric acid. The gas as it is produced enters a long column full of coke, while the acid from the chamber is run through the coke by a kind of receptacle that alternately fills and empties itself, thus giving an intermitting flow. As the acid has time to spread over the coke, the sul-phydric acid and the arsenious acid react on each other. The flow of gas is regulated according to the quantity of arsenic present. The acid thus acted on falls into a leaden recepta-Cie, is allowed to settle before it is concentrated in the lead pans, and, finally, in the platinum still. The separation and purification from nitrous acid, when the sulphuric acid contains it, can be effected by adding either a little sulphate of ammonia or alcohol in the lead pans used in the first concentration. Concentration of Sulphuric Acid.—It is well known that the acid, as it comes from the lead chambers. 13 first concentrated in lead pans. Little or no improvement has been made in this part of the concentration. In these pans the acid can only be brought to a degree of concentration equal to 1'70 sp, gr. Further concentration is carried on in glass or in platinum vessels. The high price of platinum, and its monopoly 1 y the Kus-sian Government, from which it gets into the hands of a few manufacturers, has driven many of the makers of sulphuric acid to return to the use' of glass which they had .nc; abandoned. In addition io this there has been considerable improvement in the manufacture of largo lead-glass vessels so that now about four filths of the acid made in England and Belgium is concentrated in glass, of which the original price and breakage, etc., do not exceed half of the annual interest of the cost of platinum stills. The vessels are very large, and are heated in open fire, or in iron pots, with a thin layer of sand between them and the sides of the pots. The vessels are kept constantly at work. The acid is drawn off by a. siphon, and the vessels arc immediately refilled with hot r.cid. The, temperature of the room must be kept very warm, and it. proper provision should be made for carrying o-tf the vapors. The heat and the presence of the vapors of acid are very injurious to the workmen, and they suffer more or loss- frein them. In this way, in South Laneasier alone, 'iCO tuns of sulphuric acid of 1'85 sp. gr. are manufactured weekly. In France platinum stills are almost altogether used, and the manufacturers of these vessels have exercised their ingenuity to diminish their cost, andnoneof them has succeeded so well in this ;lir ction as Messrs. Johnson Matthcy, of Hatton Garden, London. In 1862, in London, they exposed a still capable of concentrating from two to four tuns 01 acid in twenty-four hours, for not much more thaft twenty-five per cent of the foimer prices. The apparatus cost $3,300. in 1867, when I visited their establishment, they wero actively engaged in the manufacture of platinum stills, making some with the neck of the still directed upward, to prevent the violent boiling of the acid from throwing over portions of concentrated acid, The platinum stills exhibited coming from the establishments of Dcsmontes, Chapins, ant] Quenncfscn. in Paris ; Herasus, of Ilr.nau ; and Johnson and Mai they, of London, were most beautifully executed. In soldering all of these makers use gold, except the last-mentioned firm, who burn the sheets of the metal together at the seams and joints with the oxyhydrogen blowpipe, and for large vessels of platinum the last-mentioned manufacturers turn out work more to my satisfaction than any of the others. It is not usually understood that while platinum is not virtually acted on by sulphuric acid it does experience a little and gradual lose of substance by the action of the acid, and this especially when it contains nitrous acid, but this last can be prevented by adding a little sulphate of ammonia prior to distilling. Even when this precaution is taken there is still a loss, lessin new and more in old vessels, commencing with a loss of one gram and gradually incrcaninp; to two gnvms ior every tun of acid concentrated. When the platinum contains iridium the loss is diminished 50 per cent, but the Paris manufacturers, I bel;eve, are the only ones who have used iridium in their platinum, and they do not do it except by express order, for platinum that contains it is moie difficult to work. With this I will terminate the brief review of the present condition of the manufacture of sulrdinric acid in the world, as brought out by the Exposition of 1867, and by the exumi-nation of old and well-established factories. An Incident at Hie Fair ol'tlte iircrican Institute. One morning, says the Tribune, the Secr:.tary of the Board of Managers, Mr. John. W. Chambers, was having his boots blacked at the entrance of the Fair l:y a small bey, shceh-?s and stockingless. The Secretary, in his urbane manner, told this boy that if he would wash himself, and come to him the. next day, he would admit him to the Exhibition. The next morning, a young lad, with his face polished by the use of snap, appeared in the office, and asked to be admitted to (he Exhibition, as he had been promised. " When did I promise yon?" said the Secretary. " Yesterday morning, when I polished your boots." " If you are the lad, come in." He passed him to the Exhibition. Half an hour afterward, while the Secretary was passing one of the pianos, he noticed a crowd surrounding the instrument, and, to his surprise, found the young bootblack delighting the audience by the brilliant tones he was drawing from the instrument. It is a pleasure to record the fact that this young lad has teen taken into the store of the manufacturers whose piano he was then playing. These gentlemen have furnished him with a new suit of clothes, and every evening he has been heard at the Exhibition playing equally well on the piano or electric organ. The boy is an orphan. His father, a tit-iman musician, taught his infant son to play, but after the former' death his son was thrown unprotected upon the world, and, finding nothing to do, earned a precarious living by blacking boots. His names is Charles Knubel ; he is now ioutreen years of age,and we have no doubt but that he will honorably be heard of in the future. CURIOSITIES car A CITY .DIRECTORY. — It is an entertaining pastime to look over the pages of a city directory and seethe variety of curious naines and the great number of the same name it contains. For instance, the "New York City Directory, for 18C9," has the name and address of Smith recorded two thousand and fifty-nine times ; one hundred and eighty-nine bearing the given nann of John. The Murphy s number seven hundred and sixteen; sixty two bearing the name of James, one hundred and nine John, tint I fifty-nine Patrick. WE are much gratified to state that since the inauguration of President Grant, the public debt has been reduced $Ci,852,-070?5. This fact not only demonstrates the efficiency ot the present administration in the collection of revenues, "rut the the immense resources of the country. 324 Tlie New State Capitolj! Illinois. We give a view of the New State Capitol now in the course of erection in Springfield, 111. The ground plan is that of the Greek cross, arranged to present lour fronts of similar style. The order adopted is the Corinthian. The north, east, and southern fronts of the superstructure are each to be supplied with a portico of eight detached columns in front, the outer two on each side being coupled. The western faade presents the same exterior, except that when entering the building you pass into the basement through a stylobate, the portico not projecting as far as on the opposite fiont. The tambour of the dome comprises two stories, the first ornamented with disengaged columns in pairs ; and the second with pilasters. From the top of the latter springs the dome, surmounted by a lantern. There is a balustrade on the top of the entablature of the first story, consisting of pedestals and balusters. The liight from the ground to the top of the lantern is 254ft. The dome at its base is 83ft. in diameter, outside the walls. The building is 354ft. long by 240ft. wide ; the hight is 95ft. The interior is to be finished in the same elaborate style. Messrs. Cochrane Garnsey, of Chicago, are the architects ; Mr. J. W. Ackermann (late of London), acting as draftsman. The corner-stone was laid with Masonic ceremonies on the 5th day of October, 1868. The whole structure will cost $3,000,000. Rcfinlii? Oil.—How it is Done. Our readers, says the Oil City WeeMy Times, are probably, most of them, aware that petroleum is a product found in many parts of the world, and that it has been known to man for more than two thousand years ; a spring of it, on the island of Zante, one of the Ionian group, being described by Herodotus. And we read that at Agrigentum, in Sicily, petroleum was collected and burned in lamps as a substitute l'or oil ; and in more modern times Parma and Genoa in Italy were lighted with supplies of this oil obtained in Amiano and other places. We also know large supplies of it have been obtained at Bakoo, in Georgia, on the borders of the Caspian Sea, and at Rangoon, on the Irrawaddy, in Burmah, for several centuries, and that it has been for a long time in use in Persia and India, both for its lubricating and illuminating purposes, and also for preserving timber against insects and as a medicine. It has been known and collected in this region from its earliest settlement by the whites, and was previously known and used by the aborigines. The product was used in a crude state, and though its qualities were known, no progress was made in the manner of distilling it until Reichenbach, of Moravia, undertook an investigation of its properties, the results of which were published in 1830-31. These attracted the attention of scientific men, and stimulated experiments, and, in 1834, a patent was issued to Sel lique, a French chemist, for his process of refining, which, with subsequent improvements introduced and patented by him up to 1845, is the same, with a few modifications of the apparatus employed, as that now practiced. The invention was introduced into England by James Young, of Glasgow, and incidentally also into the United States. As this branch of industry just at present is occupying much attention among ? ur people, and possesses in itself considerable interest, we give below a description of the process of refining as it is now practiced. We avoid the use of technical terms, in order that we may be easily understood by all. In the early days of refining in this country stills of a capacity of from 15 to 200 barrels were used. Lately tank shaped stills of a capacity of 500 to 2,;~00 barrels have been substi tuted. These stills are filled with crude oil, and fire applied in the furnaces beneath them, and as the heat increases it causes vapors to arise on the surface, which are carried forward to pipes immersed in water, and the vapors flowing through these pipes are condensed into a liquid which runs out at the end of the pipe. The first product of the pipe is gasoline, a very light hydrocarbon, weighing on Baum's hydrometer 77. This gasoline is composed of different degrees, beginning as high as 83B., and running as low as 75. The temperature of the stills is necessarily increased as the distillation progresses, and the next product obtained from the pipe is called naphtha, benzine or benzole, which is taken from 75 to 63 B. This mixture of degrees will stand at about 67. The next production of the stills is refined petroleam, called distillate, such as used in lamps. This is produced until as the distillation progresses about eight or ten per cent of the original quantity contained in the still remains, which is called residuum or tar. This is drawn from the bottom of the still and has been generally used as waste and fuel, but of late it has been re-distilled for the purpose of obtaining paraffine and lubricating oil. ParafSne is a fatty material, resembling sperm in appearance. The product, taken off of a gravity between 63B. and the tar, called distillate, still retains a greenish color, and its disagreeable odor, and the next step in the process of refining it is the treatment with sulphuric acid. For this purpose it is placed in a tank where it is violently agitated by means of an air pump, forcing air through the oil, and while thus agitated a quantity of sulphuric acid equal to one and a half or two per cent of the oil is added, after which the agitation is continued fifteen to thirty minutes. The blast of air is then stopped and the oil allowed to settle, when the acid and impurities are drawn from the bottom. The oil is then washed, first with water, and then with caustic soda, by which means the remaining impurities are removed, and any portion of the acid remaining in the oil is neutralized. [Some parties heat the eil before treating in order to get what is called the " fire test."] The oil is then taken to shallow tanks, called bleaching tanks, where it is exposed to light and air, and allowed to settle ; it is then heated by means of a coil of steam pipe running through it, to generate all gaseou3 vapors which will ignite at a temperature below 110 Fahrenheit, and to cause their evaporation. The oil is now called a " fire test " oil and is ready to be barreled and sent to market. Ornamenting Glass, The Mechanics' Magazine states that Mr. George Rees, of Holloway, has lately patented an invention for producing ornaments or devices by vitrifying pounded glass upon glass and glazed ware, or by cementing together fragments of colored glass or glazed ware by vitrifying a layer of pounded glass on to the fragments. The glass, after it Is pounded, is sifted through sieves, the meshes of which correspond to the sizes of the particles of glass to be used on the surface of the glass or glazed ware. The new process is as follows : Take a sheet of glass and prepare the surface by brushing a gummy or other adhesive liquid thereon. Then sprinkle pounded glass over the gum, which adheres to it. The glass thus prepared is placed in a furnace, or under heat in any suitable manner, in order to vitrify the pounded glass upon the surface of the sheet glass. The pounded glass may be of one or a mixture of colors, or the sheet glass may be of a white or other color. When it is required to form a pattern on the surface of the sheet of glass, cover the intended part with gum, and then sprinkle the required colored pounded glass on it. The other portions of the pattern are likewise similarly prepared, and pounded glass of a different color is sprinkled on those. These operations are repeated until the required number of colors are sprinkled on. The sheet of glass is then heated to the required degree to reduce the pounded glass to almost a liquid state ; when the glass is removed from the furnace the pounded glass is found to have fixed itself into or on to the surface, and forms a rough face. If the sprinkled sheet of glass be left under heat for a longer time the pounded glass runs and intermixes itself in the surface, and thus produces a smoother face. In carrying out the second of the above described methods of this process the inventor takes broken or shaped fragments of colored or plain glass, or glazed ware or metal, and arranges them in any desired pattern, placing them in a metal mold. He then spreads over them a layer of pounded glass or other vitreous substance in such a manner that the powder shall enter the interstices between the fragments forming the pattern, and shall cover the entire back surface of the pattern to such a depth as may be convenient. He then removes the whole to a furnace and vitrifies the mass, thus cementing together with a thorough vitrified cement the colored device and giving it a solid back.
This article was originally published with the title "The Manufacture of Sulphuric Acid"