scale; as, for instance, in the works of Messrs. Allhuson & Sons, at Newcastle-on-Tyne, which, although not the largest, consumes weekly the following enumerated materials, in tons: coal, 2,250; pyrites, 350: nitrate of soda, 10; chalk, 900; salt, 450; manganese, 100; lime, 125.

The weekly production is: 450 tons crystallized soda, 150 tons refined alkali; 100 tons bicarbonate soda; 30 tons of caustic soda; and 110 tons chloride of lime-in all, 830 tons chemical products; enough to freight a good-sized ship.

It is not the province of this report to detail the general character of the articles exposed by the different exhibitors, except so far as this or that article may possess some special merit.

Industrial chemistry has its greatest expansion and widest range of production in France and England, especially as regards what are called the staple articles; but in the manufacture of many of the less abundant products Germany is not surpassed, and in the last five or ten years has taken rapid strides towards competing successfully with France and England in the manufacture of almost all substances.

Of course, a necessarily hurried and somewhat confused examination of the great variety of products found in the Exposition must interfere with a very satisfactory criticism in many points; and as to the pro cesses, a knowledge of them could only be obtained from more or less imperfect descriptions by the exhibitors, except when time afforded an opportunity to visit the factories, and where the owners were willing to be communicative, and allowed free access to all the apparatus when in operation.

The most striking progress, since 1862, is the invention of new colors from coal-tar, (toluidine and methylaniline,) better known as aniline colors, but especially in the improvement in the quality, and a wonder ful diminution in the cost of those previously known; the transforma tion of naphthaline into benzoic acid; the manufacture on a large scale of fluosilicic acid, destined to play an important part in the manufacture of soda and potash; and finally, other inventions and improvements which will be alluded to in detail in this report. It is proper, however, to state that the progress of the chemical arts during the past five years has not been so remarkable for any great discovery of new processes as it has been in perfecting those which had already been employed, so as to fur nish more abundant and cheaper products.

In this report the labors of the scientific men with whom I had the good fortune to be associated will be used whenever required, and without reserve, when it is conceived necessary to furnish correct and useful information to the American public; and I take this opportunity to acknowledge my indebtedness to the kindness of my associates on juries, and in the grand council, among whom I would enumerate the French and continental chemists MM. Ballard, Dumas, Liebig, St. Claire De ville, Bouterêlle, Kuhlmann, Daubrée, Hofmann, and others.

The natural subdivisions of the products of industrial chemistry bring into the foreground the acids and the alkalies. As they constitute the substructure of the chemical arts, and as of this substructure sulphuric acid is the corner stone, this acid and its manufacture will be viewed in all its bearings upon the chemistry of the Great Exposition of 1867.

2

INDUSTRIAL CHEMISTRY.

CHAPTER I.

THE MANUFACTURE OF SULPHURIC ACID.

IMPORTANCE OF this acid TO THE USEFUL ARTS-VARIOUS METHODS PROPOSED TO AVOID THE USE OF CHAMBERS-SUBSTANCES EMPLOYED IN THE MANUFACTURE-SULPHUR, EXHIBITION OF, AND PRINCIPAL SOURCES-SULPHUR FROM SODA-WASTE— BLACK-ASH, MOND'S PROCESS-SULPHUR FROM COAL GAS-FROM PYRITES-METHODS AND PROCESSES OF MANUFACTURE-SULPHUR FURNACES-LEAD CHAMBERS-PYRITES FURNACES-GERSTENHOFFER'S FURNACE-UTILIZATION OF THE RESIDUE FROM THE PYRITES FURNACE-COMBUSTION OF PYRITES COMPARED WITH THAT OF SULPHUROXIDATION OF SULPHUROUS ACID-EFFORTS TO PRODUCE SULPHURIC ACID WITHOUT THE AGENCY OF NITRIC ACID-GAY LUSSAC'S PROCESS-PURIFICATION OF THE ACID FROM ARSENIC-CONCENTRATION OF SULPHURIC ACID-PLATINUM STILLSDESCRIPTION IN DETAIL OF THE CONSTRUCTION OF SULPHURIC ACID WORKS. I-APPLICATIONS AND PROGRESS OF THE MANUFACTURE. When we glance over the chemical products that influence to the greatest extent the useful arts of society, we find them among the acids and alkalies; for by the chemical reaction of these compounds, furnished by nature or art, the manufacturing and domestic arts generally obtain a multitude of useful compounds. But of all substances that have made their imprint on the modern progress of the arts, there is no one approaching sulphuric acid in importance, produced as it is from the cheapest materials furnished by nature, and of which there seems to be inexhaustible supplies. Glass making, soap making, bleaching, calico printing, dyeing, &c., are all large debtors to sulphuric acid. It is said that the consumption of sulphuric acid in any country will show, with that of iron, its industrial activity. The low price of the acid is one of its great merits; the ordinary form known as oil of vitriol, being the most concentrated form in ordinary use, is now made in France at a cost of about one and a quarter cent per pound, and in England for a shade less; in this country ill-advised legislation makes a much higher and fluctuating

price.

No material change has taken place in the last ten years or more in the manufacture of sulphuric acid. The well-known method of converting sulphur into sulphurous acid, and completing the oxidation of it by the oxygen of the air, aided by one of the oxygen compounds of nitrogen, is still the predominant method, and, in fact, all of this acid that is manufactured, except the small quantity made by distilling copperas, and called Nordhausen acid, is made by this process.

It will not, however, be unprofitable to the readers of this report to enumerate some of the various attempts made in the last twenty years to supplant the present method in lead chambers. Lealand and Deacon,

in 1854, suggested the use of chambers made of stone, or earthenware. Simon, in 1860, proposed vulcanized gutta-percha, but on trial this substance was found more destructible than lead. Peter Ward, in 1862, proposed a series of glass sheets to increase the surface and hasten the reaction; that, however, had been used before, and as the formation of sulphuric acid is not dependent on surface action, it is of no advantage. Philips and Kuhlmann, as far back as 1838, proposed the use of heated air, and sulphurous acid passed over spongy platinum, but this has been almost forgotten. Fouché and Lepelletier, in 1850, employed a series of large Woolfe bottles instead of the lead chambers, at Javelle near Paris, but this has been long since abandoned. Kuhlmann proposed to pass a mixture of sulphide of hydrogen, obtained by proper means from soda waste, through nitric acid in stone-ware bottles, but the method was never put in practice. Petrie, in 1860, applied a system of stone-ware columns, filled with pebbles, through which currents of nitric acid and sulphurous acid in proper proportions were passed; but this has not been successfully applied. Several years ago Persoz accomplished the oxidation "by passing the sulphurous acid gas through nitric acid. diluted with from four to six volumes of water, and heating to 2129 F.. or through a mixture of nitric acid, or a nitrate with hydrochloric acid. The reaction takes place in a comparatively small vessel of suitable material; the gas arising from the deoxidation of the nitric acid is reconverted into nitrous acid by air and water. Theoretically, it works without a loss of nitric acid; nevertheless the process has never been adopted in practice, possibly from want of suitable material to withstand the com bined action of the two strong acids."

II. SUBSTANCES EMPLOYED IN THE MANUFACTURE OF SULPHURIC ACID,

SULPHUR.

There was a most beautiful display of specimens of sulphur from the south of Italy and from Sicily; and these countries furnish all the sul phur that is employed in the arts and in agriculture, except some little that is employed for domestic use in countries producing it, of which notice will be taken a little further on. While we now obtain the larger proportion of sulphuric acid made in Europe from pyrites, it is very much to be desired that new and abundant supplies of sulphur may be found, for the acid made from this substance directly is purer, and the apparatus required less expensive, than when pyrites is used. Besides the sulphur exhibited from southern Italy and Sicily, there were speci mens from Apt, in France, which locality furnishes a poor sulphur mineral. Also in the neighborhood of Constantine, in Algiers, there is native sulphur. In central Italy, near Bologna, there is a vein of sulphur ore about fifteen miles long, but the mineral is not rich, and is necessa rily taken from a great depth, sometimes over 800 feet. About 12,000 tons are produced here annually, which is almost entirely consumed