THOJfPSOLV O X S C I E N T I F I C PREPARATION A N D APPLIC.4TlON OF P A I N T . “Who manufactures waterproof paper?” ‘ ‘ W h a t is the practice in the use of the titer test a s applied to red oil?” “\That is the present address of J. E. Teeple, of New York?” ‘ ‘ l v h a t is the price of and who sells the Hoskins’ Electric Furnace?” “Please find in a recent number of Pouer an article on the Westinghouse Gas Producer. ” ‘‘\That is the so-called New York-Liverpool test for soda a s h ? ” As you will readily see, these questions are of a most varied sort, and require a wide familiarity with the contents of the library, for we never know what may be asked next. We must ever keep before US the entire resources of the collection, and trust largely to our ingenuity and cooperation of all the laboratory members in finding satisfactory replies to these inquiries. Aznis of the I,zbl-ary.-This brings us to the aims of our library: I t s first purpose must b.e to keep apace with the growing business of the laboratory and build up its resources in the most valuable way to handle the work. But this is not enough. We should be so keen to the situation as to try to sense the advance direction and movement of the business, and aim to build up our collection to meet the needs as they appear. 9 o t only this, we must bear in mind the matters of vital interest to individuals. One man wants us to note for him everything we see on fibers, another would have us watching for articles on new steels, another for anything coming from the pen of a certain writer. A11 of these must be kept constantly in mind. But with these duties, which emanate from without, we should not be satisfied. I t is for us to call also to the attention of those whom we may think will be interested such new developments, . processes, in\-entions, treatises, and SO forth, as make their appearance, for we are indeed privileged aboye the others in seeing so much that is diversified each day. With this privilege must go the added responsibility. Furthermore, we aim to keep in cooperative touch with other similar small libraries, as well as with the larger libraries, such 3 s the Boston Public Library, the Library of the Mass. Inst. of Technology, and other institutional libraries, knowing that often we must go to those sources as a last resort when our own facilities have been exhausted. A sign of real progress in the general library field which has attracted our earnest attention of late is the formation of the Special Libraries Association, which hopes to unite the interests of all small special libraries, and to be of suggestive value to them in the solution of their varied and peculiar problems. We aim to keep in close touch with this movement. Conclusion.-In conclusion, the library a s a n ad-
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junct to the industrial laboratory may be said to be a n actual necessity as soon as the laboratory h a s come to any size, and has a n accumulated history. I t facilitates the working of the organization, safeguards its resources, assists its specialists in their daily work, and makes for general efficiency. If i t fully meets its purposes, i t smooths the way and acts a s a lubricant to the wheels of the laboratory progress, encouraging and building up the office cooperation, and enlivening the esprzt d e corps among its members. The library must become “ a weapon of business,” as has been aptly said before,l rather than a mere storehouse for books, if i t is to be a real living and necessary adjunct to the industrial laboratory, and right here very much depends upon the missionary spirit of its staff. BOSTOX,1\IASS, Dec 30, 1909,
SCIENTIFIC PREPARATION AND APPLICATION O F PAINT. B y G \V THOMPSOV Received January 10, 1910
The object of this paper is to discuss, abstractly, certain questions which arise in connection with the manufacture and use of paint. I t is our purpose to see how far science will be able to help us and what the limits are, if such exist, to science as applied to the preparation and application of paint. Our purpose is to differentiate between science proper and that species of pseudo-science which is something in the nature of quackery. I t is too common a practice in th? arts to label a given product as “scientifically prepared,” on the assumption that the popular mind will purchase i t with avidity and with resulting large profit to the manufacturer. lye are glad to admit that imitation is the sincerest form of flattery. Unfortunately, this form of flattery does not help science, but, on the contrary, tends to put i t in disrepute. -1s a general proposition, scientists should condemn the misuse of the name of “science” and should not be parties to it, This does not mean that science should not be popularized. There is no scientific proposition or problem but has its human side.’ The work of Faraday, Tyndall, and Huxley in the popularization of science are monumental examples that we should pattern after. Their methods, particularly, deserve study and imitation. lye think that with them no false conclusion could possibly h a w been reached, because each conclusion was reached after careful logical thought, each premise was carefully examined before it was used and all its limitations noted, and when a final conclusion was reached, all the limitations of that conclusion were also stated. 1
From a paper entitled “The Library and t h e Business Man,” by
G. W. Lee, p:esented a t the 29th annual meeting of the American Library .4ssociation.
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T H E JOURNAL OF INDUSTRIAL A N D ENGINEERING C H E M I S T R Y .
The scientific study of any subject involves the following steps : First: The accumulation of facts and their careful study, so that there may be no question that the facts are reliable and safe within their limitations. Second: The description of these facts, which description must be accurate, careful and not subject to more than one interpretation. Proper words must be used in this description and their definitions must be clear and accurate. Third: The study sf the interrelations of these facts and the development of such numerical values for these relations as may be found to exist. Fourth: By the comparison of all the facts we may reach the condition where a hypothesis may be justifiable, for the purpose of explaining the interrelations of facts. There is no justification for the development of a hypothesis until sufficient facts are available. I n proportion as a hypothesis connects facts, so far is i t desirable, and, while i t may not explain all facts, it should not be contrary to any fact. The development of a hypothesis involves the use of the imagination, and, in so far as the use of the imagination is confined to the development of a hypothesis and is not allowed to color facts or dictate conception of laws, it performs a useful function. FLJth: Laws may be developed by the classification and the organization of facts. Hypotheses may help in the discovery of laws, but hypotheses themselves must never be confused with laws. A law is something about which there is no exception. It should, if properly stated, rest on a firm foundation of all known facts. Too a p t are we to use the word law loosely and improperly; such misuse of the word law is unscientific and cannot be too much condemned. To the scientific study of paint, no one has contributed a greater fund of information and valuable suggestions than is to be found collectively in the classical articles by the late Dr. C. B. Dudley, which appeared in the Railroad Engineering Journal a score of years ago. These articles of Dr. Dudley are worthy of reproduction and study, and to every student of paints they should be a n inspiration. The death of Dr. Dudley is a loss irreparable to the student of applied science. Facts and Conclusions.-We have outlined the scope involved in the scientific study of any subject. All facts are contributive to science, so that the accumulation of facts is a scientific operation or step. It is proper, therefore, to refer to any classified accumulation of facts as scientific, and the more carefully these facts are classified, defined and described, the more scientific their accumulation is; but, when one attempts to apply these facts and to draw conclusions from them, then the operation is scientific only whep all of the known facts are considered and the conclusions represent a complete and unbroken
Mar., 1910
chain of reasoning, without any lapses or assumptions either of facts or relation. We hear a great deal about paints “scientifically prepared,” without evidence being presented that these paints rest upon scientific foundations, properly so-called. We are told, for instance, that the best paint should have the minimum of voids in so far a s its pigment is concerned, and then we are told that a certain paint or a certain group of paints has been scientifically prepared, without evidence being offered that these paints, in so far as the pigment is concerned, do have minimum of voids. This is not right. No conclusion should be based upon one fact only and no assumption should be made as to law or theory, but each should rest upon all available, known and applicable facts; and, if there is any gap which can be supplied by experiment, that experiment should be made so as to complete the links of available evidence. Undoub tedly, science does contribute and assist in all manufacture of paint, gives information and facts that are enlightening and helpful to the manufacturer; but, to call the manufacture of paints scientific, simply because science furnishes facts, is very much like the use of the word electric in connection with carpet cleaning where electricity only is used for power. I n both cases, there is a tendency to deceive. I n the manufacture of a given paint, one scientific fact may be utilized and a hundred scientific facts may be ignored, and my contention is that no one is justified in describing a paint as scientifically prepared unless all known facts and relations are considered in its preparation. Commercially, in my opinion, this is impracticable. A small amount of paint could be prepared in this way, b u t there would have to be considered the surface to be paigted, the weather conditions in which the painting was to be done and the personal equation of the painter together with all the variables peculiar to the pigment and vehicle used. I would not, for one moment, be considered as condemning the application of science to paint manufacture; there is no limit to the usefulness of science in this respect. We are learning more and more every day, and the paint industry is advancing by leaps and bounds with the knowledge that science is furnishing it. As illustrating my views, I would mention that, a t a meeting of the American Society for Testing Materials in 1907, I suggested that a test should be made to determine the effect of pigment upon the corrosion of iron and steel. This test involved the agitation and aeration of water containing a given pigment in contact with a weighed piece of steel. A number of tests were to run a t once, SO that the agitation, aeration, etc., should be uniform. The tests, which were made at my suggestion, indicated that certain pigments accelerated corrosion,
THOMPSOiV ON SCIENTIFIC PREPARATION A N D APPLICATION OF P A I N T while other pigments retarded or inhibited corrosion. This test was suggested as giving \-aluable information which, taken in conjunction with other information, would help in the designing of a suitable paint for iron and steel. I n order to determine the value of this test, a number of painting tests were prepared and exposed, using diBerent pigments, b u t the same oil, and with all the paints spread a t a standard rate. It was thought that, while a pigment might be a n accelerator of corrosion in water, i t might act differently in linseed oil. The reports of the inspection of the painting tests so far published give us no information a s to whether the laboratory water-test is reliable or not. Individually, I a m unwilling to express opinion on this point, ahd will not anticipate the report of the Inspection Committee. But, two alternatives are before us: First: If the painting tests confirm the laboratory water-tests, then further work will have to be done to determine to what extent a n accelerating effect possessed bp one pigment can be overcome by admixture with another pigment; also, if a pigment accelerates corrosion, could not special methods of preparation be devised which would overcome this accelerating effect? Second: If the paint tests do not confirm the laboratory water- tests, investigation should be undertaken to find the cause of this disagreement. Broadly speaking, a pigment may be a n accelerator of corrosion and have other valuable properties vchich will commend i t for qprotectiT7.e coatings; and, on the other hand, a pigment may be a good retarder of corrosion b u t have other objectionable qualities which will condemn its use in protective paints. Also, a pigment may give a paint coating that is relatively impermeable, and so prevent corrosion, b u t produce a paint coating that is not reasonably permanent. In such a case, initial impermeability is of small value as compared with lack of permanence. These illustrations are presented simply to bring o u t the point we have in mind that all the qualities of a pigment must be taken into consideration when i t is used or advocated ,scientifically. We cannot discuss in this paper all of the phases of paint manufacture, nor can we consider all of the properties which a pigment might possess, b u t which must be considered when it is to be used in thc preparation of paint. Chemists are more a p t to consider pigments from the chemical, rather than from the physical, side. I t is a common practice for them to analyze a given pigment; then to find from the analysis t h a t the composition accords with what they believe to be a standard composition and then to endorse that pigment as a valuable one. The neglect of the study of the physical properties of pigments has been the cause of a great waste of money, time
and effort in paint manufacture. Analysis is perhaps the most important means of enlightenment that the paint manufacturer possesses, but his examination must not stop here. Too little study has been given to the size and shape of pigment particles and their physical relation to the vehicle used. S i z e aizd .?hafie 01 Pigment Pavticles.--The use of the words f i n e and coayse, with reference to pigments, is often misleading. We would define fineness as a word that expresses the relative number of particles in an absolute unit of volume. If the unit of volume is taken as one cubic centimeter then the word fineness corresponds to the number of particles in “S” grams of the pigment, where “ S ” equals the specific gravity of the pigment. Unfortunately, there have been no measurements of pigment particles which will give us their relative fineness in these terms. We should have this information if we would classify and describe pigments properly, according to their fineness. Practically, a pigment is not considered fine enough when it contains any gritty particles, which grit will ordinarily be caught on a fine silk bolting-cloth; but, on the other hand, a pigment may be too fine for use by itself in certain paints because i t may not contain the proper proportion of relatively coarse particles. Kow, if we had some method of determining the number of particles in an absolute unit of volum?, i t would be comparatively easy to design a paint by the admixture of pigments that would contain any desired number of particles to the absolute unit volume. Microscopic examination has not been sufficiently accurate for this purpose, for the reason that microscopic measurements of fine particles, as a tule, only take in two dimensions; and, as, with the exception of precipitated crystalline pigments, the particles are not symmetrical, i t seems almost impossible to determine the absolute volume of a given unsymmetrical pigment particle. When a pigment is made up of particles of digerent sizes, the difficulty becomes even greater. The finer the pigment is, the greater its oil-taking power is; consequently, this oil-taking power is a n indication of fineness. We do not know, however, that i t is more than a n indication, for the shape of the particles and the surface they expose to contact with the oil are also factors in the oil-taking power of the pigment. I n testing for the oil-taking power of a pigment, i t is desirable that, as far as it is possible, any chemical reaction between the pigment and the oil should be eliminated. Mineral oil is, relatively speaking, inert toward most pigments and is probably the most suitable oil to use to determine the oiltaking power of a pigmmt. There is no subject connected with the paint industry which deserves more scientific investigation than this one of the oil-taking power of pigments. Formulae should be developed to show the relation be-
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7 " I i J O l ~ I < ~ V A01: I . I~\~!ll,'.STl
