CHEMISTRY, APPLIED. Applied chemistry refers to the use made in other sciences and arts of data which have been established through chemical research. An absolutely sharp distinction between pure and applied chemistry, so-called, is well nigh impossible. The difficulties encountered in each class of work are comparable, and the ability demanded for success is equal in the two cases. The methods differ, but the principal difference is in the scale of operations and in the immediate objective. Not only do larger masses as encountered in industry involve changes in the prescribed temperature, time and concen trations, but the equipment can seldom be made of the same materials. For pure research we may draw upon platinum, quartz, alloys as may be required and laboratory glassware. In industry there must be substituted wood, iron, steel, concrete, ceramic products, alloys and other well-known and important materials of great size and strength. Often the greatest difficulty is en countered in selecting suitable apparatus for the plant, bearing in mind length of life and commercial economy. A striking example is the recently perfected method for the manufacture of nitric acid by the oxidation of ammonia, thereby displacing Chilean nitrate as a raw material for this important acid. The perfection of chrome steel and chrome iron has made possible the economic operation of this process. Application of the re search in this case awaited the production of these alloys.
C. F. Kettering has said that pure science involves getting facts when they are not needed, while applied science is obtaining these facts when they are wanted, sometimes most urgently. R. A. Millikan believes that all research, to be justified, must ulti mately be useful. The attitude of a generation or two ago, when researchers expressed the hope that their work might never be come useful and that science might always remain pure, has materially changed, due in some degree to the recognition on the part of industrialists of the vital importance of pure or funda mental research.
It is in applied chemistry that the public has the greatest interest, for it measures the value of scientific work by commercial products which it may enjoy and by other results which appeal to the aesthetic sense and make for creature comforts. The con tributions of chemistry are seldom recognized by the ultimate consumer, for their identity has become lost. The achievements of most sciences are more readily comprehended by the non technical public and it is only within a decade that efforts have been made to remedy the situation. To-day a larger proportion of the public recognizes the relations of chemistry to all activities of modern life, and without claiming for that science too large a share of credit, it may be conservatively said that with physics and mathematics chemistry occupies a fundamental place in the scheme of things.
In industry uniform results are obtained only with raw mate rials of constant quality within established limits. The simplest application of chemistry has to do with the analysis of these raw materials to ascertain whether they can be used to advantage, and particularly to guard against certain impurities or interfering sub stances which if present might result in the production of un profitable seconds or in unsalable merchandise. Analytical chem istry is the basis of plant control and at many stages in manu facture must be relied upon for the guidance of operations. This is true in the manufacture of sugar and in the production of steel, where the molten metal is often held awaiting the report of the chemist before pouring. Obviously the analyst must work at top speed. In other cases samples of ores are rushed to the labora tory, that analysis may be made while the cars are in transit, so that proper proportions may be chosen upon arrival. Another familiar application of analytical chemistry in industry is the check upon finished work which forms the basis of guarantees, particularly where goods are bought on specification or which, though finished, are semi-manufactured products for some other purpose.
Not forgetting that analytical chemistry, which tells how much of various materials are present, underlies all chemical work, attention may be directed to more difficult industrial applications. Success in the utilization of by-products and the elimination of waste in industry are two classical examples of applied chem istry. The employment of by-products has led many a manu facturer into an entirely new line. Thus, a New England lumber ing firm took up the manufacture of pulp. The installation of a plant to manufacture their own bleach gave hydrogen as a by product, and this latter was used for the hydrogenation of oil to produce hard fat for cooking purposes. Further balancing of plant operations has led this firm into a dozen chemical fields, in all of which it has become a factor of recognized importance.
The reduction of costs, elimination of waste, utilization of by-products, improvement of processes and development of en tirely new products, indicate something of applied chemistry in industry. Difficult as these applications frequently are, it is when we consider chemistry as an ally of medicine and surgery that our admiration is most excited. The extremely delicate bal ance which characterizes the human body, the multiplicity of chemical reactions constantly in progress in the cells of the body, and the lack of positive knowledge concerning these body pro cesses enormously complicate the situation which confronts chem istry applied to medicine. Beginning in many cases with natural remedies long used for various cases of illness, the chemist's first contribution has been the purification and standardization of these naturally occurring active principles. This in itself has been a noteworthy accomplishment and in several cases has been followed by the synthesis of the active principle, yielding a com pound of far greater usefulness. Some specifics like chaulmoogra oil could be used only with the greatest difficulty but a soluble salt made in the laboratory from the acids contained in the oil provided a remedy of the greatest promise in combating leprosy. The physician now has at his disposal a long list of synthetic compounds nowhere found in nature, which not only permit a varied attack upon some diseases but offer- for the first time in history specifics for certain ailments.
Medicine today, while not discarding the alliance with biology, generally recognizes that the greatest hope of the future lies in a chemical approach to a study of the human body and its diseases. Applied chemistry has shown, for example, the importance of knowing not only the type of food used but the products of this food in the alimentary tract. Perfected methods of determining sugar in the blood were the forerunner of insulin, itself separated from the pancreas, purified, and standardized for the relief of thousands of diabetics by methods based on chemistry. Indeed some regard the chemistry of the ductless glands and a chemical knowledge of the hormones as the next important step in the development of medical science. Surgery has also had its contri butions. Anaesthetics, both old and new, are chemical compounds, the preparation of which involves the utmost care to insure pu rity. The methods upon which asepsis is based rest solidly upon a foundation of applied chemistry and the great decrease in the number of deaths following operations is in no small degree due to the availability of chemical compounds used as antiseptics and germicides.
Chemistry also has a share in the perfection of special steels and alloys (q.v.) for surgical instruments and the various equip ment of the operating room. The ceramic chemist provides the enamelled metalware, the glass and the tiles. The chlorine ef fective in the Carrel-Dakin solution is the same as that used by the textile chemist for the bleaching of the textiles—and so one might run through the whole list of equipment and appur tenances.
Modern methods of food preservation (q.v.) rest on bacteri ology, physics and chemistry; and the transportation of food-stuffs would be impossible but for scientific contributions. In modern building construction further examples of applied chemistry can be found. Cement is produced and used under chemical control, as is the steel of our modern buildings. The multiplicity of col ours, shapes and textures in building units gives mute testimony to applied chemistry and her sister sciences. The strength of materials, whether used in a skyscraper, in an automobile or a pair of shears, is due to the chemical composition and the physical state of these component elements. A great field of applied sci ence has been in heat treatment, particularly of metals, to impart given characteristics due to a rearrangement of the crystalline structure.
A striking example of applied chemistry and chemical engi neering is to be found in the great petroleum (q.v.) industry, for there would already be an embarrassing shortage of motor fuels and lubricants but for applied chemistry. To-day vast quantities of fuel are removed by activated carbons and absorptive proc esses from natural gas and "casinghead" gas, while the pro portion of gasolene prepared by "cracking" continually mounts in comparison with that prepared by the older stripping methods of simple distillation. A forecast of what applied chemistry may do for the automobile and other places where the internal com bustion motor serves is seen in work abroad, where motor fuels are now prepared commercially by the hydrogenation or lique faction of coal and by the synthesis of a motor fuel, for which carbon monoxide and hydrogen derived from coal are the raw materials.
Applied chemistry has not neglected the household, for every room shows its presence. Under the U.S. pure food laws, chem istry guards the food-supply and with bacteriology guards the water-supply and safely disposes of the household wastes. In the house the wall and floor coverings bespeak applied chemistry, as do the colour and finish of the furniture, the dyes of tapestries and rugs, the waxes of the floors, the cleansing powders and soaps, and the brilliance of the illumination, which is due to the pres ence of inert gases in the incandescent bulb (see LIGHTING) and the ductile tungsten of the glowing filament. The glass ware is made by machines under chemical control, whereas for merly it had to be hand blown. The ceramic chemist points with pride to the perfection of china. The metallurgical chemist offers evidences of his contribution not only in the metalware through out the house, but in the kitchen, where his stainless steel owes to chromium this prized characteristic, and where stainless non tarnishing iron or monel metal may compete with aluminium and steel in kitchen utensils. Chemistry has had a part in pro ducing the several motors which now perform the drudgery of the household. It is a chemical compound which circulates in the mechanical refrigerator, expanding to cool the food and being compressed by the motor for expansion again. The record of the phonograph is a molded chemical compound with certain fillers, and chemistry is present throughout the radio set.
Well-meaning efforts to outlaw chemical warfare fail to take into consideration the inseparable relation between the chemicals demanded for all types of lawful peace-time industry and those needed in chemical warfare. The most effective chemical war fare agents are composed of such simple materials as sulphur, chlorine, alcohol and the like. It should also be borne in mind that the by-products of chemical research which are come upon sometimes unexpectedly may also prove to be useful materials in warfare (see CHEMICAL WARFARE).
The natural sciences from astronomy to zoology contribute, often in unexpected ways, to industrial development. It is im proper and unbecoming for any single science to claim an undue share for what has been accomplished, but it seems fair to point out that, whatever may be contributed by the other sciences, chemistry in its application to all forms of human activity may properly be credited certainly with no less than any of her sister sciences. (See various related subjects under other headings.) BIBLIOGRAPHY.--H. E. Howe, ed. Chemistry in Industry, vol. i.Bibliography.--H. E. Howe, ed. Chemistry in Industry, vol. i.
and ii., Chemical Foundation, Inc. (New York) ; J. Stieglitz, ed. Chemistry in Medicine (New York) ; H. E. Howe, Chemistry in the World's Work (New York) ; F. L. Darrow, The Story of Chemistry (Indianapolis) ; E. E. Slosson, Creative Chemistry; R. K. Duncan, Chemistry of Commerce; H. E. Howe and F. M. Turner, Jr., Chemistry and the Home (New York) . (H. E. H.)