niton. The platinum becomes deep black and thus entirely loses its transparency; and it is impossible after a few minutes to see any light through the platinized plates. But before the attack began a few observations were made indicating as the refraction (-1) of niton a figure approximating 0.001633 for white light, or about 45 times that of helium, 0.000035. You will perhaps remember that Mr. Cuthbertson pointed out a very curious relationship among the figures expressing the refractions of inert elements. Those of helium, neon, argon, krypton, and xenon show the simple relation 1,2, 8, 12, and 20. That of niton seems to be in relationship with the others.

The possibility of weighing such minimal quantities suggests investigations which must be very interesting. We might, for instance, calculate the thickness of the layers of gas attached to solid objects, for their weights are quite perceptible. Dr. Whitlaw-Gray weighed a very light capsule of gold with a surface of about 2.5 square centimeters. After heating it to redness he at once replaced it on the balance and counterpoised it. It gained in weight for two days, the total increase being 1,000 millionths of a milligram. Calculating the thickness of such a layer of air, it appears to be seven molecules thick. There is evidently much to be done in that respect, for the substances, the nature of the gas, the temperature, and the pressure may be varied at pleasure.

We have also learned another extraordinary fact. We needed pure water which should leave no solid residue in evaporation. Although we distilled water in vessels of platinum, silica, and silver, we could never obtain a drop but there remained after evaporation a crystalline deposit. We even attempted synthetic water prepared by burning hydrogen in contact with chilled vessels of glass, silica, platinum, and silver. The drops obtained all left a similar deposit weighing about 100 millionths the drop. We spent a weary fortnight in attempts of this kind, and finally discovered that no residue is obtained when water is evaporated in a current of air filtered through cotton wool. The residue came from the dust suspended in the air. According to their appearance the crystals consisted for the most part of common salt, carbonate of lime, and sulphate of lime.

Thus it is evident that water in evaporating is charged with electricity and attracts dust, which possesses a relatively great weight. Gentlemen, these are some of the experiments we have been carrying out during the last few years. Instruments such as the spectroscope, the microscope, and the electroscope have been highly perfected for the investigation of minimal quantities. We have often had reason to regret that our means of determining the quantity of matter by its weight and volume have lagged so much behind. I trust we have not wearied you in giving some account of our attempts to see the invisible, to touch the intangible, and to weigh the imponderable.

85360°-SM 1912-16

THE LATEST ACHIEVEMENTS AND PROBLEMS OF THE

CHEMICAL INDUSTRY.1

By Prof. Dr. Carl DUISBERG,

Of Eberfeld, Germany.

Probably in no domain of human knowledge and endeavor have the combined forces of theory and practice, intimately acting and reacting upon each other, made such immense strides and led to the solution of such difficult problems as in the chemical industry, an industry which, indeed, had its beginnings in the distant past, but in its vast development and international character is essentially a child of modern times. Success has so emboldened this industry that it considers itself capable of solving any problem, provided the men in its service are well trained in theory and practice and ready to devote themselves to the best of their ability, with patience and perseverance, to the object in view. This has been shown by the struggle between the contact process of producing sulphuric acid and the old “chamber process"; by the rivalry between the Solvay process and the Le Blanc method in the manufacture of soda; by the production of nitric acid and its salts by direct oxidation of nitrogen of the air under the influence of the heat of the electric discharge; by the manufacture of ammonia from atmospheric nitrogen indirectly via calcium cyanamide, and directly by combination with hydrogen; by the replacement of madder by alizarine, and of natural by synthetic indigo, as well as by innumerable other instances in the color, perfume, and pharmaceutical industries.

If, before an audience not wholly consisting of chemists, I venture, within the brief period of an hour, to describe the latest achievements of the chemical industry and to recount the problems that are engaging our attention, I must restrict myself to a great extent both in the choice of the subject matter and its mode of presentation. We can, indeed, merely touch upon the most important happenings in our industry and must, from the very outset, refrain from a thorough discussion of the subject, either from the purely chemical or the technical side. However, what can not be described for lack of

1 General lecture at Eighth International Congress of Applied Chemistry, College of the City of New York, Sept. 9, 1912. Reprinted by permission from author's pamphlet.

time, and what we should very much like to add for the sake of those chemists who are present, is illustrated by that rich collection of diagrams, products, and materials of all kinds. What can neither be mentioned in my paper nor illustrated by these exhibits will be demonstrated by means of lantern slides, and, should you possess patience enough, I shall show you at the conclusion of my address one of the newest factories which the German chemical industry has built on the Rhine, with its various manufacturing departments, and, above all, its provisions for the welfare of its employees.

In the spirit of Faust, "Who brings much will bring something to many," I invite you to make a flight with me in an airship, as it were, over the fields where the chemical industry holds sway, and, from our point of vantage, to take a bird's-eye view of the latest achievements of this industry. Now and then we shall make a landing and examine the most attractive features a little more closely.

PRODUCTION OF POWER.

The question of power, which is of the utmost importance in every industry, and especially in the great synthetic processes by means of which nitric acid and ammonia are manufactured, is now dominated by the perfected utilization of hydraulic power and the development of the turbine. Not only does the transmission of electric energy render it possible to utilize water power at great distances, but it also allows of the transmission of power evolved at the coal mines and the peat fields to distant points, thus eliminating the necessity of transporting the fuel itself. Recently we also learned to apply the principles of the water turbine to the steam turbine. But this advance over the piston steam engine, which Watt so ingeniously constructed about 150 years ago, has already been surpassed by benzine, petroleum, or oil motors (Diesel motors), and, above all, by the reliable gas engines which are driven by blast-furnace gases, Mond gas, and more recently by peat gas.

PRODUCTION OF BY-PRODUCTS.

The manufacture of by-products goes hand in hand with this more direct generation of energy from fuel. These products include ammonium sulphate, of such great importance in agriculture, and the tar distillation products, so indispensable in the color industry. The latest and most rational method of utilizing the peat or turf beds, which are so plentiful in Germany and in many other countries, is practiced in Schweger Moor, near Osnabrück, according to a process discovered by Frank and Caro. There peat gas is produced and utilized and ammonia obtained as a by-product, the required power being generated in a 3,000-horsepower central electric power station.

The moorland, after removal of the peat, is rendered serviceable for agricultural purposes.

At that place nearly 2,500 to 2,600 cubic meters of gas, with 1,000 to 1,300 calories of heat, were obtained from 1,000 kilograms of absolutely water-free peat in the form of air-dried peat, with 45 to 60 or 70 per cent of moisture. This gas represents energy equal to 1,000 horsepower hours, equal to 700 kilowatt hours, after deducting the heat and power used for the operation of the gas works. In addition 35 kilograms of ammonium sulphate were produced from the above quantity of peat, which contains 1 per cent of nitrogen.

The greatest problem of power production, the direct conversion of coal into electric energy by means of gas batteries, a problem which we had hoped to solve 25 years ago, is still to-day nothing more than a dream.

PRODUCTION OF COLD.

Besides the problem of power and heat, the question of refrigeration is one of growing importance to the chemical industry. Instead of the ammonia machines with which a temperature of minus 20° C. can be attained, we employ to-day sulphurous-acid machines, or, better still, resort to the carbonic-acid gasifier, which yields a temperature of 40° C. below zero. It is hoped in the near future to produce. refrigerating machines which, by the use of suitable hydrocarbons, will give temperatures of minus 80° C. Plants for the liquefaction of air, producing as low a temperature as minus 190° C., are becoming more and more common, and are especially profitable where gas mixtures rich in oxygen, or where pure nitrogen, which are simultaneously produced, can be utilized. Diagrams showing the process invented by Linde for the rectification of liquid air with the object of isolating nitrogen and oxygen are exhibited here. The Badische Anilin and Soda Fabrik in Ludwigshafen on the Rhine intends to manufacture hydrogen from water gas in a similar way and to utilize the carbon monoxide, which is simultaneously obtained, as a source of power. In a large plant which is being erected the firm is going to produce ammonia synthetically by combining, according to Haber's invention, pure nitrogen, obtained by the liquefaction and rectification of air, with hydrogen manufactured as above. Particulars about this process will be given during the congress by Prof. Bernthsen in his lecture on "Synthetic ammonia."

SIZE OF APPARATUS.

Influenced by the Solvay process for the manufacture of soda and its pecuniary advantages, the apparatus used in the chemical industry have enormously increased in size. In this respect the United States, no doubt on account of the example set by the iron industry,