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ical operations, particularly in the manufacture of sulfuric acid, and the chemist has assisted considerably in determining the best leads for such purposes. The development of lead alloys since modern chemistry has made its influence felt has been comparatively slight. Metallographical work has thrown a great deal of light upon these alloys and indicated many things with regard to their constitution and possible usefulness. It has helped in the determination of relative values. It cannot be considered, however, that chemistry has developed new lead alloys of great commercial value. The uses of metallic lead have increased considerably, more, however, through the development of other branches of science. When we come t o the compounds of lead and their uses, we find that here too most of the processes now in general operation were developed before the advent of modern chemistry. White lead is still made by the old Dutch process, and while in Germany and France the chamber and precipitation processes have been developed, no new qualities of value have been imparted to white lead by these processes, and Dutch process white lead is still considered the standard. I n this country the manufacture of white lead by the Carter process has shown considerable growth, and it was the understanding of the chemical reactions taking place in the manufacture of white lead CONTRIBUTIONS OF THE CHEMIST TO THE LEAD by the Dutch process that brought about the final developINDUSTRY ment of the Carter or cylinder process, as well as the more recent By G. W. THOMPSON so-called " mild " process invented by Rowley. Chief Chemist, National Lead Company Chemistry has indeed been a great help in the understanding To start with, we must admit t h a t the possibilities for accom- of all of the reactions t h a t take place in the manufacture of plishment in the lead industry by the chemist are, for obvious white lead and it has helped here to reduce manufacturing costs reasons, much more limited than in some of the newer indus- and save losses. All of these things have been accomplished tries. Lead smelting and the manufacture of most lead com- simply because of the better understanding of the reactions which take place. No specifically great improvement, however, has pounds was fairly well developed before modern chemistry beresulted from this better understanding of reactions. The gan. Lead was known t o the ancients, as well as were most of the lead compounds, which are now produced in large quan- oxides of lead, litharge and red lead, are manufactured practities. The great help modern chemistry has afforded is in the tically as they were before the advent of modern chemistry. It is true that in the manufacture of nitrite of soda by the lead direction of preventing losses and systematizing smelting and method, a considerable amount of litharge was made until manufacturing operations. I n the smelting of lead, there have been no radical departures the advent of cheaper methods of manufacture of nitrite of due t o the influence of chemistry. The old methods of oxida- soda as a by-product of the nitrate industry in Norway. The tion and reduction are still in vogue. Many attempts have development of the storage battery industry has created a been made by chemists, particularly electrochemists, to develop great demand for red lead and litharge, and as the storage batsimpler methods for the production of lead from its ores. None tery industry is electrochemical in its character, it may be considered with propriety t h a t in this branch of industry chemisof these, however, has been commercially successful. The principal influence of the chemist, as indicated above, try has been of great assistance. The use of lead oxides in has been in the study of the losses incident t o smelting and the . the curing and vulcanization of rubber goes back to the time of reducing of these losses to a minimum. The chemist has thereGoodyear, and it is very doubtful if a t t h a t time or even a t fore contributed here principally to a better understanding of the present day, the function which lead oxides perform is propthe operations of smelting. His influence has also been felt erly understood. The best information obtainable indicates in the development of methods for the concentration of lead that the lead oxides act as catalyzing agents, producing greater from its ores. Nost of these methods are, however, distinctly uniformity in vulcanization, carrying on reactions which are mechanical, and while the modern methods of oil flotation started either with or without heat and bringing the curing and may be considered chemical, their influence upon lead concen- vulcanization about with more uniform results. The oxides tration has not been so great as it has been with other metals. of lead which are used in the glass industry are made by the old It is true also t h a t the chemist has done his part in those opera- methods. The glass industry itself follows the old empirical tions connected with the recovery, utilization and production methods, in which chemistry has had little part in improving under controlled conditions of fumed products, particularly in results. The study of glass, however, has resulted in the dethe production of basic sulfate of lead and the leaded zinc oxides. velopment of a better understanding of what glass is and how it In the refining of lead the chemist has helped through the can be made more suitable and permanent. introduction of electrolytic methods, as in the Betts process. The function of lead salts in, driers in the paint industry is This process, however, could hardly compete in cost with the practically chemical, and much information has been obtained older methods devised by Pattinson and Parkes, which methods, as to the action of driers, giving quantitative knowledge, which while involving principles of physical chemistry, can hardly be con- has helped in the preparation of better driers and product considered as distinctly chemical processes. The use of the Betts protaining them. The influence of the chemist upon the paint incess has been particularly serviceable in the recovery of bismuth dustry involving the use of lead compounds has been entirely from metallic lead, which bismuth remains as a slime or mud. subordinate t o the practical results obtained. Undoubtedly It can hardly be said that the uses of metallic lead have been the influence of the chemist has been felt in the better underincreased through the help of the chemist. Sheet lead and lead standing of paint problems, but progress in this direction has pipe have, of course, been used to a large extent in most chem- been unfortunately handicapped by the development of many
I n the essential oil field also the chemist has rendered great service. It is no longer necessary to depend wholly upon the nose test in judgiug the value of an essential oil. Such progress has been made in the way of analysis t h a t the perfumer is enabled t o obtain not only pure oils, but such t h a t are rich in active constituents. The composition and properties of the essential oils are so well understood to-day that the Pharmacopoeias have adopted requirements concerning them which are specific and exacting. While not a n extremely large industry, perfumery does figure in the daily life of the average American, and without a doubt brings occasional aesthetic delights to every living being who is blessed with the sense of smell. I n the United States, the value of finished products, in which perfumery plays a n important part, amounted to several hundred million dollars last year. Just as the chemist has found the delightful fragrance of new mown hay t o be due to the crystalline lactone coumarin, so in time he will discover and synthesize the refreshing odor of the sea-borne breeze, the exhilarating fragrance abounding within the forest after a warm rain, and the many charming odors which prevail a t the various seasons in the fields. 712 THIRD STREET,BOONE,IOWA
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fallacious hypotheses, which the chemist is only now beginning t o overcome. Very few new salts of lead have been developed having commercial value or importance. Acetate of lead and nitrate of lead are still manufactured by the old processes and chemistry has helped in their manufacture only to a slight extent. The use of arsenate of lead as a n insecticide having qualities superior t o the ordinary arsenates and arsenites of copper, etc., has grown within the last few years, with promise of still greater progress. Arsenate of lead has the advantage over other arsenical compounds of not injuring foliage to as great a n extent, and remaining where it is put for a longer time. It will be seen, therefore, that what I stated in the beginning is true. The chemist’s principal influence in the lead industry has been in the better understanding of chemical reactions involved in the production, manufacture and use of lead and its compounds. Chemistry has helped in the modification of lead products t o make them better and more suitable for use. It cannot be said, however, that outside of lead refining by the Betts process, the use of lead compounds in storage battery manufacture and in the production of arsenate of lead, that chemistry has had a conspicuous part. Chemistry has undoubtedly been responsible for many lead industries being able to hold their own in competition with other products, but beyond this and the part which this has in the general application of chemical knowledge, chemistry has done little. 129 YORKSTREET, BROOKLYN, N. Y.
CONTRIBUTIONS OF THE CHEMIST TO THE PAINT AND VARNISH INDUSTRY By MAXIMILIAN TOCR Director of Laboratory of Toch Brothers
The contribution of the chemist to the paint and varnish industry is not a very long story, for prior to twenty-two or twenty-three years ago the paint and varnish industry was based on rule of thumb entirely, and i t is only within the last ten years t h a t the raw materials pertaining t o the manufacture of paint have been systematically classified and illustrated by photomicrographs. If you take the example of white lead, which has been mentioned by Pliny as having been used four hundred years before Christ, re-invented by the Dutch over three hundred years ago, it will be found that this material was empirically made and in a “hit or miss” fashion. It is only within the last few years t h a t the large lead concerns have employed able chemists who have systematized the manufacture of white lead so that all batches are uniformly produced. It was the custom in the paint industry that dry color manufacturers, whose business really was the manufacture of high type chemicals, had practical men who owned formulas and guarded them as zealously as the alleged secrets of the masonic order are hidden. I knew a well-known manufacturer of chrome green, which in the paint industry is a mixture of Prussian blue and chrome yellow, who was entirely a t the mercy of his foreman because his foreman never would divulge the actual working formula of the green that he made. For many years I have enjoyed the confidence of many of our competitors, and it would not be amiss to cite a single example of the method by which the paint or dry color industry was conducted in former years. A very large manufacturer of chrome yellow came to me one day and told me that he made upwards of one million pounds per year and did not make any money. H e showed me the cost of his raw materials and the cost of his labor and could not understand where his loss came in. I examined his factory, calculated for him the amount of acetate of lead necessary to react upon a given amount of potassium dichromate and then made a n analysis of the waste water from
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his factory, and showed him that 40,000 pounds of sugar of lead solution were going into the sewer every year, simply because he had no man in charge who knew what he was doing scientifically. I could give many instances of this kind, and it is a gratification for me to know that many of the chemists now employed in the paint and varnish industry have been originally selected by me, and t h a t my firm, though really insignificant as compared with some of the large paint concerns, has, at this writing, five chemists including myself, and that we have had some slight measure of success is due to the scientific control of the products that we make. Fifteen years ago I doubt whether there was any large varnish concern in the United States who had a chemist; in fact, chemists were then as they are now-frowned down upon by the practical superintendent, who always desired to surround his doings with a witchcraft and chicanery that made him imposing in the eyes of his principal; but fortunately those days have passed and the varnish foreman is more or less dominated now by the chemist. I have been so personally identified with the chemistry of paints and varnishes that those who read or hear this will know that there is absolutely no egotism in what I am saying. I n the oId days of the Chemists’ Club, the late Professor Morris Loeb and I were the targets of every unemployed chemist in the City of h-ew York, a t least that is the way it appeared: the present existing Bureau of Employment was started by me with the help of Professor Loeb, and many of the paint and varnish chemists today owe their positions to this Bureau of Employment. This has been further reaching than the paint and varnish industry, because the oilcloth, linoleum, leather and printing ink industries, all of which use paint and varnish in different forms, are now more or less conducted on scientific principles, and many such large works are supervised by competent chemists who were originally recommended by the Bureau of Employment of the Chemists’ Club. I think this small contribution will indicate what a tremendous influence the chemist has had upon the paint, varnish and allied industries, particularly the paint chemist, who was unknown only a few short years ago. 320 FIFTHAvE., NEWYORK
CONTRIBUTIONS OF THE CHEMIST TO THE PHOTOGRAPHIC INDUSTRY B y FRANCIS C . FRARY Professor of Chemistry, University of Minnesota
If we ask what the chemist has done for photography within the last quarter-century, we may well receive the answer, “everything.” For indeed there is little in modern photography which is more than a quarter-century old, and it is the developments of the last two decades that have popularized photography and a t the same time wonderfully increased its usefulness to science. Among the pioneers in the development of the modern “gaslight” papers, with their wonderful adaptability and variety, we are proud to number one of the foremost chemical engineers in this country; and none of the host of competing papers which has since arisen, could have been produced without the chemist. Careful chemical control of the quality of the paper-stock, the gelatine, and the silver salts used, is one of the first requisites in the manufacture of any photographic paper. The older printing-out paper, with all of its beauty of detail and gradation, required negatives of a quality which the average amateur seldom obtains; and it requires a modern paper t o make a satisfactory print from the under-timed “snap-shots” which are the inevitable result of the popularizing of photography. Moreover, the possibility of making prints by any common artificial light has placed photography within the reach of thousands who could never have used the older papers.
