replace the barium chloride solution when flowing out. The tube a t the dropping point then has the crosssection shown at c. I think t h a t i t is unnecessary, especially when the solution contains only moderate amounts of sulfate, to stir during precipitation when using this dropper, as, the two solutions being a t about the same temperature, the boiling continues vigorously, and further agitation is not required. The precipitation of barium sulfate in this manner requires no attention after the solution is set on the hot plate except t o tip up the tube and t o set aside t o digest later, and one man can carry on a number of precipitations a t one time. I n the determination of sulfur trioxide in cement in a limited time I obtain the best results under the following constant conditions: wt. cement, z grams :
hot water added, 30 cc:. ; conc. HC1 added, 8 cc. (making about 3 cc. free acid in final solution or about 0 . j per cent. acidity) ; boiling I minute, filtering, washing twice ; precipitating volume, 2 5 0 cc. ; volume BaCl, solution, I O cc. I O per cent. ; time adding BaC1, solution, about z minutes; time boiling after adding BaCl, solution, j minutes; time digesting. I hour; filtering; washing 5 times. 4 series of fifty determinations of sulfur trioxide in cement made recently by this method gave the following results : Gram iiverage weight T(aS04 for series.. . . . . . . . . 0.091s Weight BaS04 from composite (1). . . . . . . . . . . . . . 0.0918 Weight BaSOl from composite ( 2 ' ) .. . . . . . . . 0.0923
Per cent. SOs 1.575 1.575 1.58
Although small amounts of barium sulfate can bc recovered after several hours' standing from filtrate5 obtained after one hour digestion on hot plate, still results by the above method have always been found to be consistent, and to wait twelve hours or so in order t o add a possible one-hundredth of one per cent to a result seems unnecessary in technical work. If the above method were universally used there mould probably be much closer agreement in the results o f different analysts. especially in the cement industry. THE TEXAS PORTLAND CEMEST C o CEVIENT.TEXAS
AN ADAPTED WILEY EXTRACTOR FOR RUBBER EXTRACTIONS R y CHARLES P.
The ordinary Soxhlet extractor is too small f u r acetone extractions when large quantities of rubbw are desired. The Proctor extractor used in tannin extractions is also not satisfactory for rubber work. For charges up to 2 j o grams, a modified or adapted Wiley extractor has been used for several years and has given satisfactory results. This apparatus consists of the well-known Wiley metallic condenser, b u t in place of the original reservoir, a large ( 2 inches in diameter), long (IS inches), a.nd strong glass tube with ground thick lipped top is substituted. The uniform diameter of the tube permits of large charges of thin sheeted rubber carefully rolled upon fabric being inserted into the tube, suspended from the condenser within range of the drip of the condensed and falling solvent. To prevent a contamination of the purified rubber by accidental splashing of the resin solution, a disk of filter paper or cotton is inserted between the hanging charge and the solvent reservoir. A metal spiral made of sheet tin is useful in prcvcnting a superheating of the solvent and consequent foaming. A steam bath may be utilized in furnishing the rcquired heat for acetonic and alcoholic extractions. Higher temperatures for nitrobenzene or kerosene work are obtained by direct flame carefully regulated. or by a paraffine bath. 395 DOYLESTREET AKRON,OHIO
ADDRESSES COMMENTS ON THE REPORT OF THE INVESTIGATION O F THE UNITED STATES PATENT OFFICE' BY L. H . BAEKELAND Received April 18, 1913
Whoever is interested in the patent situation of this country. should make it his duty to read the unusually interesting publication just issued by the U. S. Government, which covers 624 closely printed pages. On August z I , 19 I 2 , the following joint resolution was passed: "That the President of the United States be, and he is hereby, I Sixty-second Congress. 3 d Session, House of Representatives, Document S o . 1110. Report of the Investigation of the United S t a t e s P a t e n t Office. made by the President's Commission on Economy and Efficiency, TI-ashington, December 9 , 1 9 1 2 .
Fl>X
Received March 2 2 . 1913
II
requested to cause the accountants and experts from official and private life now or hereafter employed in the inquiry into meth ods of transacting the public business of the Government in the several executive departments and other executive Government establishments, known as the Commission on Economy and Efficiency, to investigate fully and carefully the administration of the Patent Office with a view of determining whether or not the present methods, personnel equipment, and building of said office are adequate for the performance of its functions taking into consideration the present character and volume o l business, and also such increase in complexity or volume as may reasonably be expected in the future, and to ascertain and recommend specifically to Congress not later than December I O ,
418
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T H E J O U R N A L OF I N D U S T R I A L A N D E,VGINEERING C H E M I S T R Y
VOI.5 , No. 5
1912,what changes in law, what increases in appropriations As to the needed changes in our patent laws, the remark is made that the present law is substantially the same as the act and what additional building accommodations, may be necessary of 1836. There is a significant allusion to the conservativeness to enable the Patent Office to discharge its functions in a thorof lawyers and their opposition against any changes in procedure. oughly efficient and economical manner, and to what extent any expenditures which may be recommended can be met by “No change, hon-ever much it may be needed to keep pace increases of Patent Office fees. with changed conditions, can be made xrithout vigorous oppo“A411expense incurred in carrying out the purposes of this sition due to a large extent to that inherent prejudice against resolution shall be paid out of any funds in the Treasury of the disturbing the daily routine life and the inconvenience of adaptUnited States not otherwise appropriated, and the sum necesing one’s mind to a new course of action. . . . . . . . Recommendasary for said purposes is hereby appropriated: PROVIDED,tions made by the present Commissioner of Patents for the That the total expense authorized by this resolution shall not amendment of laws to effect what he considers are improvements exceed the sum of $IO,OOO.” in the methods of the office and to expedite its work, are opposed The report, as presented, is signed by Frederick A. Cleveland, by those who do not agree with him as to the wisdom of the Walter I%-.Wanvick, and illerrit 0. Chance, Commissioners on changes as well as by those whose financial interests would be Economy and Efficiency. affected unfavorably the commission is convinced that This interesting report enters into the many ramifications any proposed change in the patent law and almost any proposed of our patent system, shows up its defects and indicates in a change in the methods of procedure in the Patent Office, will practical way possible methods of improvement. arouse opposition from some persons interested in securing patents.” An enormous amount of precise information has been collected This statement is very well corroborated by the answers to by the above-mentioned commission, but what is more impresthe list of questions sent out by the Economy Commission to sive is that all this has been accomplished with the expenditure members of the bar, inventors and others interested in matters of such a comparatively small sum of money as $10,000, and before the Patent Office. More than 400 replies were received. the report should have been prepared and published three months On most questions there was a considerable divergency of and a half after the resolution was approved. This in itself is opinion. a worthy example of “economy and efficiency.” But even here it is significant that on question No. 24, relative With these data a t hand, in addition to the report of the to the desirability of creating one single Court of Patent Appeals, hearings on the Oldfield Bill (see report No. 1161, to accompany H. R. 23,417, by Hon. W. A Oldfield, House of Representatives, the answers were practically all affirmative and only a few op62nd Congress, zd Session), any future commission for the re- posed. Questions I , 2 , and 3 asking opinions as to the advisability vision of our patent system will have its work much simplified. of abolishing one of the two appeals in the office and creating Certain defects in the handling of the personnel of the patent one appeal board of five or six members mere answered in the office are pointed out; for instance, it is mentioned that there affirmative in about 80 per cent of the replies. The direct are no efficiency records for the examining force and that for many years there have been no examinations for the purpose negative to these questions mas less than 20 per cent. The trend of the opinions expressed lies decidedly toward a single of determining the efficiency of examiners and regulating their appeal to a board in the office, particular stress being laid on promotions and reductions. Such efficiency records, in conthe importance of having the work of the primary examiner junction with a n examination system, would tend to encourage all employees to do their best work and would make adequate performed in a thorough and capable manner. The great majority of answers opposed the sitting of the commissioner, salaries a real and lasting benefit to the service. the assistant commissioners, or any administrative officer on Emphatic stress is laid on the unsuitability of the present this board, the idea being expressed that thc commissioner Patent Office. should be left free to devote his time to purely administrative “ I n the preliminary survey preceding the investigation the commission was impressed with the idea that the building ac- duties. Answering question No. 14 “to what extent should the decommodations for the Patent Office are soinadequate as to render cision on such appeal operate as a final adjudication of patentextremely difficult any substantial improvement in the work ability,” a small number answered that the decision should be of the office. This impression has been changed as a result of final, and a few that it should not be final. Some favored it the investigation until it has become a settled conviction that being final only as to adverse decisions. Other suggestions any permanent improvement in the quantity and quality of were: It should be final, b u t not as against newly discovered work done by the office, if done a t a reasonable cost, must wait, upon provision being made for adequate office accommoda- prior a r t . in case of litigation under the patent; decision of the Patent Office in interference cases to be final and only to be tions for the force of more than goo people employed in the opened in court upon new evidence found, as the proceedings Patent Office.” are far less expensive in the office than in the courts. I t is a hopeful sign that the Bulkley Bill (H. R. 28,193, 62d Chapter 4 is devoted entirely to a n examination of our cumCongress, 3d Session) should already have taken up this matter, brous and time-robbing system of interference. The commisand intends to provide a $4,000,000 fireproof building. I t is questionable, however, whether this sum of money will be sioners conclude that it would be better not to make any important changes in our present interference procedure. They sufficient for the purpose. When we take in consideration that the Patent Office has now a n accumulated surplus of $7,000,000 seem to overlook the fact that our interference system, as it over all its expenses, there is no reason why this surplus should stands to-day, hardly protects the “first” inventor if the latter does not possess the abundant cash required to defend his rights not be used for providing a suitable building, and the equipment against wcalthy opponents. Furthermore, a good patent systhat goes with it tem should be devised in the interest of the nation, the public Through the courtesy of the authorities of the German Patent Office, I have recently been enabled to inspect that magnificent a t large, and not for the limited individual benefit of some inventor or another. patent office building in Berlin, and its operation. I have The essence of good patent law is to induce inventors to disbeen more than ever impressed with the fact how antiquated close their invention as promptly as possible, so that the public a n d inadequate our Washington Patent Office equipment has may have the early benefit of such publication. Our interferbecome in vieT1- of the enormously increased development of ence proceedings, in conjunction with other defects in our methods our country.
of allowing patents, encourage systematic delay in the publication of patents; in reality, a premium is noiv put on such delays. All this would be much simpler if in all interference cases priority were allowed to the independent inventor who has filcd his patent first, provided he has not copied nor stolen the invention from others. The German law allows an almost absolute claim to priority to tbc earlier applicant. This system, therefore, has the great advantage of simplicity over the system in practice in the United States, but it may become a source of injustice in case the later applicant is really the earlier inventor. However, the later applicant has only himself to blame if he does not file his application in due time, instead of doing as is now the case, purposely postponing the filing of his claims under the immunity of our interference rules. This finally comes down to the question whether it is better to confer the right of priority to the earlier datc of application which can clearly and instantly be established. or to the date of conceiving the invention and reducing it to practice, which brings forth all the uncertainties, vagueness, which frequently make our interference proceedings so absurdly long, complicated and expensive. Our present intcrference rules are undeniably a great handicap to the inventor of limited means; and our system is detrimental to the best interests of the nation. Indeed. it delays the essential benefit of publication of the invention; furthermore, in some eases it becomes a positive danger to any industrial enterprise when nobody knows whether he is infringing some unpublished patent rights which h a r e been silently ripening to interference proceedings, protected by all the possible customary delaj-s sanctioned by our rules of practice. The German and British systems permit the filing of opposition proceedings vithin a certain period after a patent is allowed; this is a n excellent simplified substitute for our interference proceedings. Members of the German patent office have invariably declared that they attach considerable importance to thc maintenance of this system. because it tends to reduce the responsibility of the examiners and to enhance public confidence in the integrity and capability of the hoard of examiners: this in itself checks criticism to which such sensitive men as inventors are only too prone after thay have encountered some disappointments in the office. I have noticed the same uniformly favorable opinion among German inventors, as \;-ell as patent attorneys and manufacturers, as to the advantages of the so-called opposition proceedings. Many of them, however, are of the belief that the British system, (which allo7vs opposition to a patent during a certain period after the latter has been printed and published) is, however, more practical and expedicnt than the German method where opposition has to be filed bejove the patent has been printed, and before copies are rcadily obtainable except by means of special copies ma& from the pending application a t the patent office. As another check to worthless patents, the German law provides a safeguard in the method of annulment proceedings. Such proceedings are quite distinct and independent from any infringement proceedings. Any person, whether sued for infringement or not, may apply to the patent office for the annulment of any patent if he can prove that a t the time of application the subject matter was publicly known, or was claimed in a prior patent, or was illegally appropriated by the patentee. Hon-ever, in the latter case, annulment proceedings can be instituted only by the person from x h o m the invention was appropriated. In a similar manner, a person who believes he can prove that he is prior inventor of a n invention patented to another, and that the patentee has stolen his invention, can sue the patentee for an assignment of the patent to him. There is still another safeguard in the German lam. called the which prevents the danright of prior use (’C’orbenutzu~~gsrecht) gerous possibility which now exists in the United States, that a
business enterprise, started in good faith. might be held up a t any timeTon account of a long secretly pending patent application. I n Germany, any person who. a t the date of application of a patent, has already used the invention in that country, or made the necessary preparations for such use, has the right to use the invention for the requirements of his oivn business in his oivn works; but this right can only be transferred to others together with the good-will of the business. I t should be noted here that sometimes the suggestion has been made to cut down entirely our examination system, as well as our interference system, and to come back to a plain registration system, which \vas abandoned in this country 76 years ago, but is now knoxvn as the French system. The report oi‘ the commission says emphatically: “To return to such a system would be a backvard step.” “n‘hile there are some persons interested in the subject who believe that the L-nitcd States should return to the system of registering patents and allon- all questions of validity and priority of invention to be determined in the courts, these persons are decidedly in the minority.” In France, a.patent may exist for years before an examination is made as to priority and patentability, because such a scrutiny only takes place in case of a patent suit: and even then, the examination is not made by technical experts but by the ordinary courts, who may or may not decide to hear experts. This absurd system accounts for the scant csi.eem with xvhich patents are treated in the Latin countrics where the French system is in use. The French system has certainly not shown the stimulating cff ect to invention and enterprise which the American system has introduced in such nations like Germany, England and the Scandinavian countries, which have adopted it in a more or less modified form. It should be mentioned, furthermore, that in all countries xvhere the French system is used, a patent really begins to be looked upon as serious af tcr the corresponding German patent has been issued. This in itself, is the best tribute to the practical value of the prcliminary examination system. The most striking incongruity in our American system is that after a patent ha5 been granted by a technical board, in infringcment cases, this same patent is reexamined as to validity and patentability by a non-technical judge, in a non-technical court. This is the main reason Tvhy our systcm has been defined as “best in the vorld for lairycrs and worst for inventors.” (H. IY.Leonard, E k c t r z c d Tl’orld, 51, ~ o j j . ) In this relation, the following words are very significant: “The commission has been unable to see the benefit of the present system by which every question relating to a patent can be litigated in any part of the country. “XYhen the Patent Office shall haiTe been furnished with adequate quarters and equipment and the most efficient personnel, it Trill be time LO consider to what extent the decision of this officeought to be final in patcnt matters. IYhen that time comes, it may be found advisable to consider Tvhethcr a patent should not be madc \-alid by lax\- to the extent of giving the patentee a right to an injunction in a case against alleged infringers. “This would probablj- require the adoption of the practice of publishing applications n-hen ready for allon-ance, v i t h the opportunity for anyone t o file opposition within a limited time, and if none were filed or it was decided that the patent should be issued, it ought to he held valid for all purposes until declared invalid by court. Such a system would probably require also that any person claiming to be injured by the grant of a patent could file annulment proccedings within a limited period ..... “There is a general complaint, although the commission is not advised as to the facts of the matter, that a grant of a patent is of no value to a n inventor if it is in the interest of any person or corporation of financial strength to infringe it. The results after a patentee wins a n infringement suit arc often not of rcal
e
420
T H E JOURNAL OF I X D C S T R I A L AA’D ESGI.YEERI!VG CHEAVIISTRY
bcnefit to him, for, if he survives the suit, the actual recovery of adequate damages is exceptional. “ I t would seem that the remedy for many of the difficulties of the present situation regarding patents will be found in the development of the Patent Office as a n administrative court in which all questions relating to patents, excepting the question of infringement, will be finally decided, subject only to a review by an appeal to a court of patent appeals, with possibly a provision for certain questions going to the Supreme Court. Giving such jurisdiction to the Patent Officc, and to one court, will tend to the development of a system of patent law that mill be a benefit to the public and a protection to real inventors.” Chapters 5 and 6 are devoted to the classification division and to the scientific library and the search room. They point out the existing defects and contain many excellent suggestions. The fact that in the files of the patent office, there are still missing copies of 60,000 German patents and of 6,000 French patents, is significant. It is true that for a certain period, France discontinued publishing its patents. Several other countries, for instance, Canada and Belgium, do not publish their patents, excepting by title. Yet copies of every one of the patents published in those countries ought to be available in our search room; indeed, many of these patents contain important disclosures which have a direct bearing on the validity of the patents issued by the U. S.Patent Office. I t would not involve a n exorbitant expense to have typewritten copies made of the patents filed by those countries. -4more satisfactory method would be t o compel all countries, which belong to the International Union, to print every patent issued by them. This subject should be taken up a t the next meeting of the International Convention, and could hardly cause any opposition, since almost all countries belonging to the convention already print these patents. A very detailed criticism of the totally inadequate conditions of the building and the equipment of the patent office is made, and specific recommendations are offered for remedying this intolerable condition. The commission overlooks the fact that the equipment of a new patent office will never be complete unless provision be made for a chemical, a physical and a mechanical laboratory, wheie simple direct tests can be made under the supervision of two or three experts-a chemist, a physicist, and an engineer; so that many simple questions which now baffle the examiners in their decisions on patentability could easily and quickly be decided by a direct test. Such a laboratory exists in the German Patent Office building. The report is accompanied by several appendices, all of which make interesting reading. These appendices are as follows : A. History of the United States patent system. B. United States laws and rules of practice relating to patents, trade-marks, and prints and labels. C. The German patent law. D. The English patent law. E. Discussion of the German patent law and patent procedure. F. A comparison of the patent laws and procedure in Germany, England and the United States. G. Methods of examining applications. H . Publications of the patent office. I. Statement of the business of the patent office. J. Bibliography of the United States Patent Officc. K. Classification of patents and printed publications. Specially instructive are appendices E and F, \mitten exprcssly by Prof. Dr. Albert Osterrieth and Mr. A. du Bois-Reymond, both of Berlin, and leading authorities on the subject. The latter paper not only compares the advantages of the laws of Germany, England and the United States, but points out their relative defects which experience has proved to exist and, furthermore, discusses the differences in procedure in these countries.
1’01. 5 , NO. 5
This discussion of the advantages and defects of the leading patent systems of the world is a most valuable contribution and will be very useful in the consideration of changes that arc suggested in thc law and procedure of the patent system of the United States. I t is specially interesting to read the comments on the practical value of the so-called compulsory working clause or compulsory license clause in Germany and England, in view of the fact that an attempt is being made by the Oldfield Bill, and other proposed measures, to introduce this innovation in the United States. I n Germany, the compulsory working of patents has practically been abandoned and is merely kept up as a club to compel some countries like England, France and others into reciprocity treaties waiving the compulsory working of patents. To the credit of the present commissioner of patents, it should be mentioned that he has already negotiated a ‘treaty to that effect with Germany. The United States, in accord with Germany, might have a decisive influence in abolishing this compulsory working clause in foreign countries, so irksome to American patentees, by passing a law whereby foreigners are compelled to work their patents in the Cnited States, unless their country waives compulsory working of patents issued to American inventors. The first Oldfield Bill had a clause of this kind, but it was so erroneously worded that in some paradoxical way, it gave superior advantages to foreigners over American inventors. As to the compulsory working and compulsory license in Germany, we might best quote Prof. Osterrieth: “ I n fact, very few patents have been revoked in Germany for non-working (one patent out of more than 2 0 0 0 ) . On the other hand, the working clause always threatens the patentee, hanging over his head like the sword of Damocles, as a great expert in patent matters once said. Besides, experience has shown that petitions for revocation arc mostly entered by patent infringers, using the working clause as a defense. “This explains why in the last 15 years, there has been a very strong movement in Germany for abolishing the xorking clause. This first induced the German Government to abolish the obligation of working by international treaties in the relations with Italy, Switzerland and x i t h the United States. And finally the old working clause of the first patent law was abolished by the law of June 6, 19I I . “Since this law came into force, i . e . , July, 1911, no obligation of working a patent exists in Germany. No patent can be revoked on the ground that it is not being worked. Yet, considering the legislation of some countries which threaten foreign patentees with revocation of these patents, if the invention is exclusively or mainly manufactured abroad, the German Government resolved to provide for a similar clause, applicable a t least against such countries where German manufacturers have to suffer from such legislation. “Ithasthereforebeenstatedin theabovementioned law of 191 I , that a patent can be revoked, as far as international treaties do not provide to the contrary, if the invention is exclusively or mainly manufactured or carried out outside the German Empire, and its possessions. This clause does evidently not apply to citizens of the United States, even if an American has acquired a German patent from a patentee belonging to another country. Yet this might lead to abuses. Therefore, there has been provided a complementary clause, saying that transferring a patent to another person is ineffective if this transfer has been made only with the intention of avoiding revocation. “According to the former German lawa patent could be revoked, after cxpiration of three years from the date of granting, if i t appeared i n the Public interest that permission to use the invention be granted to others but the patentee refused to give such permission in return for adequate remuneration with adequate
May, 1913
THE JOURAY.4L OF IAITDl;STRIAL
security. This clause has proved most ineffective as no sing/(, case of rezocatzon o j - a patent o n this ground has been known. Therefore, when the abolition of the working clause was discussed, it was suggested to do away also with that clause on the obligation of granting licenses. I t was objected that cases might happen \There the use of a patented invention by others than the patentee could be necessary for the public weuare, for instance, manufacturing certain drugs in case of an epidemic.” This consideration seemed to justify the insertion of the following clause in that new law of 19I I : “If the patentee refuses to grant license to another for using the invention upon the offer of a n adequate compensation and security, such grant for using the invention can be allowed (compulsory license), if such granting seems necessary in the public interest. The grant. may be limited or subject t o special conditions.” This detailed report of the Commission on Economy and Efficiency is supplemented by some specific recommendations as follolvs: I. That a new building specially designed, equipped, and furnished be constructed on a suitable site in the city of Washington, for the exclusive use of the United States Patent Office. 11. That the number of officers and employees of the United States Patent Office be increased, and the increases and readjustments of salaries be made as shown in detail in this report involving an increase of 36 in the number of employees and a total increase of $236,550 in the pay roll. 111. That the Commissioner of Patents be the head of the Patent Office; that his duties be the same as are now prescribed by law, excepting that he be relieved from the consideration of cases on appeal; that he be aided by a n assistant commissioner and seven supervising examiners in the administrative work, including control of the methods and procedure of the 43 examining divisions in the allowance and rejection of applications for patents. I V . That one appeal within the United States Patent Office be eliminated; that the number of members of the board of examiners in chief of the Patent Office be increased from three to five; that all appeals within the office be taken to that board; that its decision be the decision of the Patent Office; that the appeal therefrom be to the Court of Appeals of the District of Columbia, as now allowed from the decisions of the Commissioner of Patents. V. That the fee for filing an application be increased from$15 to $20; that appeal fees be adjusted to the conditions arising from the elimination of one appeal; that a fee of 2 5 cents be charged for each additional patent, etc., included in one instrument presented for record; that all fees be paid directly to the Patent Office; that refundment of fees paid by mistake be made by the financial clerk and not by warrant from the Treasury. VI. That the life of a patent be so limited as to expire 19 years from the date of filing the application therefor, excluding the time (not exceeding two years) during which a n application may be involved in interference. VII. That the work of reclassifying patents and digesting of printed publications, and providing facilities for simplifying and making more accurate the search, be recognized by an appropriation for an adequate force to be employed upon such work. VIII. That the subscription price of the Official Gazette be increased froin $5.00 to $10.00 and the method of distribution to libraries be changed toreduce the number of copies so distributed. IX. That all the work of producing the publications of the Patent Office, including copies of patents, be done a t the Government Printing Office. X. That a n appropriation be made for the repair of thc rooms occupied by the Patent Office and for the installation of suitable lighting and ventilating facilities and for the purchase of new furniture and equipment. YONKERS, S. Y
1 21
THE PLASTICITY O F CLAY BY
JOHS
STE!V>\K’F
I t is one of the peculiaritics of hum:m endeavor t h a t action taken for a certain purpose often results in the accomplishment of an entirely different and unexpected result. A priori it would hardly be expected that a study of the organic phosphorus of the soil would have any bearing on the plasticity of clay, but such is the infinite inter-ramification of the facts of nature that they lead to strange results. So far as the writer is aware, no satisfactory explanation of the cause of the plasticity of clay has ever been advanced. Numerous attempts to explain the phenomenon have been madc, hut none of the results has met with general acceptance. HilgardZreviewed some of the most important of these attempts, but indicated by his trcatment of the subject that the question \vas still a n open one. Hopkins3 mentions plasticity as a ProPerty of clay. Thorp,4 in his exposition of the chemistry of the ceramic industries, offers no explanation of the cause of the plasticity of clay, although without this property the indust r y could not exist. Ashley5 reviewed the literature of colloids and of clay, and made a study of the absorptivc power of some clays for certain dyes. His Tvork was based on the idea that “clay is . . . a mixture of granular matter and a colloid gel,” and had for its purpose the development of a method of measuring the plasticity of clay by utilizing the absorptive power of colloids for this purpose. In a later publication, Ashleye discusses plasticity of clay on the same general lines. He sa$s: “The colloid matter of clays may be considered as consisting of complex mineral and organic acids and salts. ” Bleininger’ studied the effects of heating clays to tcmperatures under 400’. He found t h a t the plasticity \vas decreased and t h a t there \\-as not a corresponding change in the absorptive poxers of the clay. Acheson,s in 1901, ground clay in a water extract of straw and found t h a t this treatment increased the plasticity, He considered this result to be due t o the organic matter in the water extract. In 1904 this result was claimed to he due to gallotannic acid, and seems8 t o have been regarded as a physical and not a chemical action. Thus the importance of Acheson’s observation does not seem to have been recognized by investigators. P. Rohland’O attributed the plasticity of clay t o hydroxides of Si, Al, and Fe. He noted that fuller’s earth absorbs unsaturated hydrocarbons, and he recommended the use uf clay to purify factory wastes. There arc some facts relating to the plasticity of clay which have received general recognition and acceptance as being truc. . . . . . i t is First, pzwe clay is not plastic. Hilgard” says: readily mistaken for chalk (and is sometimes used as such), being powdery to the touch and entirely devoid of plasticity . , . . . ” Those engaged in the ceramic industries call the purcr clays “lean” on account of their lack of plasticity. Second, i m p u r e clays are the plastic ones. These arc the “fat” clays, so-called by those engaged in the ceramic industries because of their possession of plasticity. Third, it is a common practice in the ceramic industries to mine the clay :And allow it to weather” for months before use. This is said to increase the plasticity. Fourth, ignitioit destroys the plasticity of clay. Attempts to ‘ I .
Paper presented a t the Eighth Internatiunal Congress of Applied Chemistry, S e w York, Septemlier, 19 12. oils,” 1906, pp. 5 7 - 6 2 , 3 Hopkins’ “Soil Fertility and Permanent Agriculture,” P . .5< 4 “Outlines of Industrial Chemistry,” 1909, pp. l ~ J l - Z ~ l l . C . S . G . S..Bull. 388 (1909). 0 C. A , , 5, 174-5 (1911). I b i d . , 5, 175 (1911). “Some Chemical Problems oi To-day,” H . K . I l u n c n n , 1911. P I I . 118-1 19.
“Soils,” 1906, p. 5 9 . T h o r p “Outlines of Industrial Chemistry,” 1909, 194, Roscoe and Schorlemmer. “Treatise on Chemistry,” [ I ] 2, 4 9 5 ( 1 S 8 3 > , new editiiJn. 12
