Apr., 1915
T H E JOURNAL OF I N D U S T R I A L A N D ENGINEERING CHEMISTRY
both for the chemist and the manufacturer. Under such conditions the preserver of fruit and vegetable products will, by the application of chemistry, be able to utilize all waste and even retain and preserve the bloom on the fruit and the spicy odor of it as well-and thus beat out the meat packer, who admits losing the squeal. SAXFRAXCISCO, CALIFORNIA
CONTRIBUTIONS OF THE CHEMIST TO T H E POTABLE WATER INDUSTRY B y Ww. P. MASON Professor of Chemistry Rensselaer Polytechnic Institute
Less than a generation ago, the chemist approached the question of “Potable Water” with a confidence born of his ignorance, and he issued his pronouncements after an examination less thorough than that required to determine the fitness of a water for boiler uses. E. Frankland and J. A Wanklyn in England, and W. R. Nichols in America recognized that something more was needed than a knowledge of “total solids,” “mineral matter” and “loss on ignition” before an opinion could be formulated as to the potability of the sample, and to them are largely due the beginnings of that advance in the technique of water examination which has taken such strides in our day. It was perhaps to have been expected that, in their enthusiasm over their improved analytical processes, the water chemists should make the blunder, into which the bacteriologists fell a t a later day, of demanding more from their recent discoveries than could with reason be asked. Thus we find Wanklyn dogmatizing upon the infallibility of the ‘‘ albuminoid ammonia” process and insisting upon the reliability of a fixed standard for all waters, which measure should divide the good from the bad with accuracy Slowly, however, there crept into the minds of chemists the conviction that general standards could not be maintained, as waters were too various for their application; and therefrom developed the tendency towards that breadth of view in the matter of interpretation of analytical results which has led to a recognition of the great importance of what is now termed the “Sanitary Survey ” Considering that any one of the sundry items reported in an ordinary water analysis, is in itself harmless, and, therefore, is scrutinized only because of the possible bad company it might keep, it was soon admitted that an unusually high reading might be accounted for through some perfectly innocent cause in water from one locality and, therefore, justify a favorable report, while the same data from water derived elsewhere might determine condemnation of the sample. The dictum is not new but it is as true as when first uttered that “no opinion should be risked as to the quality of a water from an unknown source.’’ It IS even possible to add this further word, that, although we need all the light that chemistry, bacteriology and microscopy can throw upon the question as to the suitability of a water supply, nevertheless if but a single branch of inquiry be available the “Sanitary Survey” is the one to be chosen. While declining to be bound by the hard and fast “standards of purity” advocated in the past, chemists have nevertheless done faithful work towards the establishment of suitable “comparates” where such records can be of service. For instance, those chemists who undertook a determination of the “normal chlorine” of Massachusetts and Connecticut, and who gathered the data for plotting the “iso-chlors” of those states, certainly added much towards making an interpretation of analytical results more reliable. Analytical averages for gound waters are now separated from those of surface supplies; the measure of “hardness” is so defined that the non-chemical laundry-man or boiler .user can
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easily secure the information he needs; and, further, the public is informed as to how much iron would likely be objected to by the average community. “Turbidity” and “color” are no longer described in words but are reported in definite “parts per million,” as are the other items of the analysis, to the great advantage of the manager of the city filter, whose duty it is to watch the work done by the purification plant for which he is responsible. The day is passed when a municipal filter is expected to run itself, except during its period of occasional cleaning. A chemist and bacteriologist will now be found continually on duty, ready to detect faulty operation on the part of the plant and prepared to apply those remedies which experience has shown to be proper under the circumstances. “ Pin-point coagulation ” and its relation to water temperature is one of the disturbances of a mechanical filter that the chemist in charge must watch, for as the late autumn approaches, and the thermometer reads forty or less, the flocks of aluminum hydroxide decrease in size and tend more and more to pass through the sand bed. Without a trained man in charge, aluminum compounds are likely to pass the filter a t any time, for it is an easy matter to carelessly allow an overdose of alum to reach the filtered water; but the detection of too great an addition of coagulant is one of the simplest jobs the attending chemist has to do and it requires small effort on his part to keep down the alum bill. When “bleach” is needed, as so often is the case, its strength in “available chlorine” must be determined, not only that the management may know the quality of the goods for which payment is made but also that a proper “dose” may be added to the water. Enough must be turned into the supply to do the work demanded, but an overdose should be avoided lest its disagreeable taste be complained of by the consumers. Who but the chemist in charge is to fix the proper value for the dose of “bleach” and who else can suggest a remedy if the right quantity should accidentally be exceeded? It would not seem a very complex matter to supply properly purified water to a few people, but when this procedure is to be undertaken upon a large scale, the duties of the chemist in charge of the work become most varied. He has to examine and report not only upon the water product itself but also upon all the odds and ends of supplies and equipments that enter the establishment. Such a chemist must of necessity be a bacteriologist, and it would be of advantage to him should he be an electrician, mechanical engineer, biologist and general sanitarian as well. So it is seen that the old rivalries between the chemist and the bacteriologist in the field of water supply have been outgrown and extinguished in that fusion of activities which produced the present water purveyor. There is yet much of the chemist in his makeup because there is much that is chemical in the detail of his daily work. Without bacteriology, he admittedly could not go far, because with that branch of his mental equipment he detects the present danger lurking in the water under investigation, but it is to chemistry he must turn in order to inquire as to the future and to estimate the probability of a yet distant danger following upon present safety. No better example of what is meant could be given than to cite a very recent instance falling within the writer’s experience Two wells, each fifty feet in diameter, were sunk eighteen feet deep in a sandy soil, within a half mile of each other. They were intended for use “in tandem” upon the same water service. One of these was, by bacteriological examination, shown to be grossly contaminated, a showing which was confirmed by both chemical analysis and the sanitary survey; the water from the other well appeared to be singularly good from the bacteriological standpoint but the chemical analysis indicated very material “past pollution” and the sanitary survey
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THE JOURNAL OF INDUSTRIAL A N D ENGIXEERING CHEMISTRY
located the cause for such indication. The sandy soil had filtered out and removed all offending organispls but the soluble material which accompanied them had passed on and revealed a threatening danger. Of course, the objection to the water was, not what it contained a t the time of observation, but what i t would be likely t o contain in the future should the protective barriers of nature be overworked or broken down. Without the chemical side of the investigation no comprehensive report could have been rendered in this case. And so, in short, chemistry takes its position on the prophetic side of water examination, and i t is aided, not supplanted, by the science of the bacteriologist. The latter's work has to do with showing things as they now exist, while the chemist's field reaches back into the past and throws as well no uncertain light into the future. TROY, NEWYORK
CONTRIBUTIONS O F T H E CHEMIST TO T H E CELLULOID AND NITROCELLULOSE INDUSTRY By R. C. S C H ~ ~ P P H A U S Consulting Chemist
When we bear in mind that the discovery of nitrocellulose was due to chemical research, w e perceive a t once that the development of industries based on this discovery must be indissolubly linked with the patient work of the chemist. It need hardly be dwelt upon t h a t the hopes built on the availability of nitrocellulose as a successor t o gunpowder were realized only forty years later. Yet the new material quickly found its place in the arts of peace, first as photographic and surgical collodion. The employment of nitrocellulose as the base or an ingredient of explosives, either propelling or shattering agents, is beyond the scope of this article and will not be discussed. However, i t must not be forgotten that the work done by chemists in this field, both for war offices and private manufacturers, was of great assistance to the workers in other directions and t h a t the results achieved by this second line of investigators paved the way for the manufacture of gelatinated explosive nitrocellulose compounds, the modern powders and explosives. ,411 the applications of nitrocellulose in the arts are based on the fact that the structure of its various forms may be broken down by the action of suitable solvents. The discoverer of nitrocellulose was already in possession of its colloid solution. The differences between soluble and insoluble varieties (in certain solvents) were quickly recognized, and representatives of four great groups of solvents were known a t the very dawn of the nitrocellulose industries, viz. : I-Alcohols : Methyl and ethyl alcohols. a-Esters : Methyl and ethyl acetates. 3-Ketones : -4cetone. 4-Mixed solvents : Ethyl alcohol and ethyl ether. With these fundamental facts to start from there began a long line of chemical activity. Among the industries developed, the manufacture of pyroxylin plastics occupies the first place, and the other developments, such as the production of photographic films, artificial leather, pyroxylin varnishes and even artificial silk made from collodion may be regarded as offshoots from this branch. The activity of the chemist in this industry is twofold, covering research and control of operations. It was necessary to investigate and select the best raw materials, devise methods for their purification and to solve the problem of the production of a nitrocellulose of even composition on a large scale. The various industries require pyroxylin of different characteristics, such as nitrogen content, solubility in specified solvents and viscosity of such solutions. These conditions were worked out in the factories, and the x-ork done in their laboratories would fill volumes. reedless t o say that the influence of proportion of acid t o cellulose, the composition of the acid bath, temperature and time factors were known to the chemists in these industries long before the laboratories of scientific insti-
Vol. 7 , NQ. 4
tutions took these matters up. Important discoveries concerning the connection between solubility, viscosity and mode of production were made and put to practical use. The methods of analysis of the acids and their mixtures as well as of the nitrocellulose and its finished compounds were brought to the greatest refinement and developed to a state which permitted the quick attainment of results that technical operations call for. 'The determination of oxalic acid in the nitrating bath, For instance, which the latest literature lays much stress on, has been a routine operation for a long period in well-conducted factories. Other problems sprang from the demand for perfectly transparent materials, requiring special methods of mashing and stabilizing the nitrated cellulose. In the designing of the most efficient apparatus for the manufacture of the ever-growing quantities of nitrocellulose the chemist took a promincnt part. The urgent call for an economical method of regenerating the weakened acid bath was met by the simple and elegant process of adding fuming sulfuric acid to the fortifying mixture Tvhich enables a skilled operator to avoid any accumrilation of spent acids with all its drawbacks. The best way of removing the larger part of water from the washed nitrocellulose consists in displacing the water by alcohol. While the problems prcseiitcd appear a t first glance purely physical, yet their solution required the alert cooperation of the chemist. So much for the basic material. I n the industry of pyroxylin plastics the original Spill solvent of 1869, commercial grain alcohol and camphor, still reigns supreme. I n the intervening years many expedients have been tried, owing to the fiscal policies of various countries in regard to alcohol, and wood alcohol and fusel oil or its separate constituents have found wide application. The other groups of solvents were advantageously extended by the introduction of the esters of the alcohols of fusel oil and of polyatomic alcohols, of ethers of higher alcohols and phenols, of aromatic nitroderivatives and other compounds. These solvents are, however, of more importance in the allied industries. With the rising price of camphor, which is nearly treble of what it was thirty years ago, the old attempts to produce the material From cheaper products were stimulated, and today large factories exist for its manufacture, thus putting a check on unreasonable advances. The same cause led t o the elaboration of methods of recovering camphor from scrap materials that cannot be utilized in other ways. The feverish searching for a camphor substitute has been less successful though large classes of solid solvents of pyroxylin were discovered. X few of them, belonging t o the group of acid derivatives of aromatic amins, find a limited application for special purposes. Chemical investigation has led to a revision of the old mixing formulas for the manufacture of pyroxylin plastics, and the old empirical standards have been abandoned. The chemist is continually called upon for advice regxding the application of coloring matters and other materials €or ob taining special effects. The allied industries are based on the same principles. In the nianulacture of photographic films, varnishes and artificial silk from pyroxylin flowing solutions are prepared. Artificial silk niade from dissolved nitrocellulose and subsequently (preferably) denitrated is being superseded by threads made from cellulose brought into solution by other means. There is not a factory of pyroxylin compounds of any importance in existence today that has not its busy stafl of analytical, managing and research chemists. 175 P E A R L STREET, N E W Y O R K
CONTRIBUTIONS OF THE CHEMIST TO T H E GLASS INDUSTRY By A. A. ROUGHTOM Vice-president Corning Glass Works
The first experiments dealing with the chemical composition of glass of which we have record were directed toward producing
