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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 N G I N E E R I N G C H E M I S T R Y
“butter” from the seeds, of the malma or illupei tree in India is described. (P. 908.) The mineral products of Ireland include coal, iron ore, fire clay, bauxite, rock salt, barytes, soap stone, ocher, umber, and pyrite. (P. 909.) The construction of large blast furnaces in Rouen, France, was started, to use ore from Spain, Algeria, and Sweden. [Report of consul dated July 2 2 . 1 (P.938.) The use of esparto fiber from Algeria, for the manufacture of paper, mats, etc., is described. (P. 972.) High pressure incandescent gas lamps are being tried a t Montevideo, Uruguay, using gas at a pressure of 2 t o 2.5 meters of water. The mantles are inclosed in silica globes. (P. 990.) The Egyptian phosphate output is increasing, being shipped principally to Japan. (P. 991.) Peach kernels from California have been shipped to Germany t o be used in the manufacture of prussic acid, and “bitter almonds.” (P.I I IO.) The market for American cottonseed oil in India is discussed. (Pp. 1111-5.) The possibility of Americans obtaining a supply of German dyestuffs Via Holland is discussed. (P. I I IS.) Rubber shipments from the Amazon valley show a slight decrease. (P. I I 19.)
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The principal mineral products of Alsace-Lorraine are iron ore, coal, salt, potash, petroleum, and asphalt. (Pp. 1126-7.) The cultivation of kapols for fiber, in Ceylon is described. (P. 1160.) The status of the iron, zinc, lead, copper, coal, petroleum and sulfur industries in Japan is discussed. (Pp. 897-907.) Information as to rubber cultivation in India is given. (P. 1034.1 An appropriation of $50,000 for promoting trade with Latin America is now available, (P. 1041.) A list of publications on South American trade is given. (Pp. 1012-20.) Many requests have just been received from “Latin American countries” for various articles, including: Soap, cement, paper, starch, sugar, matches, oils, paints, drugs, photographic supplies, glassware, enameled ware, kerosene, coal, coke, soda, pig iron, galvanized iron, sheep dip, wax candles, malt, copper, and tin plate. (PP. 849, 929, 977, 1109,1042,1156.) An immediate market is needed for many supplies from Latin America, including : Cacao, wax, hides, tallow, balata, quebracho wood and extract, divi-divi, bones, sodium nitrate, copper, tagua nuts, sarsaparilla, tin, tungsten, rubber, copper, silver, and linseed. (Pp. IOIO, 1071, 1156.) A demand is received from Canada for shipments of steel, window glass, white lead, and flaxseed. (P. 1011.)
BOOK REVIEWS
The Occupational Diseases, their Causation, Symptoms, TreatM.D. ment and Prevention. By W. GILMANTHOMPSON, New York and London: D. Appleton and Company. 1914. Pp. xxvi 724, with 118 illustrations. Price, $5.00 net. The reviewer recently referred t o the growing interest which various American organizations are taking in the diseases of occupation.’ Until the publication of this treatise, however, there had been no work of reference on the subject by a n American authority on industrial hygiene. “To supply in some measure this lack, the present work has been undertaken, particularly with the aim of meeting the needs of American practitioners of medicine, as well as those whose industrial or philanthropic interests require a comprehensive summary of the nature and prevalence of the occupational disease hazards as they obtain in this country.” In preparing this work, which is more comprehensive than Arlidge’s “ Diseases of Occupation,” Weyl’s “ Arbeiterkrankheiten,” Roth’s “ Kompendium der Gewerbekrankheiten,” Hirt’s “ Krankheiten des Arbeiter,” Albrecht’s “ Gewebehygiene,” Layet’s “ Gewerbepathologie,” or Oliver’s “ Diseases of Occupation,” Dr. Thompson has enriched medical science with much new material. His investigations of the phenomena of industrial diseases, some of which are published herein for the first time, and still more his improvement of professional treatment have won for him a permanent reputation; but above all else he is inclined t o assist his fellow-men to the utmost of his power. And this he has done in this noteworthy treatise, the preparation of which, as even one familiar with but medical propaedeutics can observe, has been a labor of love. The work is divided into seven parts: Part I, History Classification, General Pathology and Etiology ; Part 11, General Remedial Measures; Part 111, Diseases Due to Irritant Substances; Part IV, Diseases Due to Harmful Environment; Part V, Special Occupational Diseases; Part VI, Influence of Special Conditions on the Occupational Diseases; and Part VII, Miscellaneous Occupational Diseases Grouped by Industries not Included in the Foregoing Classification. There are also four appendices: Tabulated List of the Principal Harmful Substances and Their Effects; Tabular List of Important In1
THISJOURNAL, 6 , 526.
871
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dustries in which the Workman is Subjected to Several Hazards; Tabulated List of the Principal Industries in which Dust Constitutes the Essential Hazard; and Main Provisions of Existing Laws (1914)Relative to the Reporting of Occupational Diseases by Physicians. Theoretical toxicological details are omitted as are discussions of .disputed scientific points. Owing to the general excellence of all parts of this treatise, one were unappreciative of diligence did he not feel tempted to refrain from critical comment thereon. However, an endeavor to be helpful prompts the reviewer t o indicate whereby its usefulness might be further augmented. Dr. Thompson is, of course, eminently equipped with the very special knowledge required to describe and discuss the pathology of the lesions set up and the preventive measures necessary to combat them; but his descriptions of manufacturing operations, evidently taken largely from medical reports, and his purely chemical considerations, are less accurate ; in fact, the book is in need of chemical revision. Shellac is not “secreted by a scale-forming insect” (p. 166); lead does not enter into the manufacture of aluminum foil (p. 199);i t should have been noted that acroleic vapors arise when metal articles are dipped into molten fat in galvanizing and tinning (p. 3 0 5 ) ; the account of the formation of nitrous gases (p. 372) is inaccurate; the highly poisonous nature of osmium tetroxide (p. 375) is due to the reduction by the tissues to metallic osmium; picric acid (p. 375) is manufactured by the nitration of phenol; “chinin” and “chinon” are mentioned (pp. 376 and 688), the first as a “petroleum by-product,” reference being had to quinine and quinone ; paraphenylenediamine (p. 381)is not manufactured from petroleum; asphalt is classed under “insoluble inorganic dusts” on p. 400, and under “organic dusts” on p. 692; plate glass is cast, not blown (p. 409), although the time is approaching when it will be blown mechanically; oxalic acid is not properly classified on p. 420 (in this connection i t may be noted that a t the only oxalic acid manufactory in this country the preparation is carried on in open vessels); sodium and potassium chlorides are not “made by electrolysis” (p. 589); flint is hardly a “silicious variety of quartz” (p. 620); and cinnabar is mentioned in the place of stibnite on p. 665.
T H E J O U R N A L O F I N D U S T R I A L A N D ENGIiVEERING C H E M I S T R Y
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The chemical industry offers naturally a wide field for the occurrence of occupational diseases; but it can take credit for the way in which the incidence of industrial poisoning has been minimized in view of the extent of the risks which often threaten. Despite all hygienic regulations, however, the risk of poisoning cannot be entirely banished : wholly to prevent accidents and illness is as impossible as totally to prevent accidents by the mechanical guarding of machinery. I
Dr. Thompson’s book is not burdened with morbidity and mortality statistics, eight pages being devoted to these subjects. This is pleasing, for undigested statistics are indeed a fruitful source of nightmare. Apparently alarming increases in disease, based on comparison with ten, twenty or fifty years ago, generally overlook the most probable cause for the increase, the more complete and accurate statistics of the present day. I n this connection, it may be noted, however, that later statistics relating to the German chemical industries than those for I907 (p. 29) were available prior to the publication of this work; for instance, the disease statistics of the chemical industries for 191I were reported by Curschmann in Chemische Industrie, 36, 5 8 , and the annual report of the Koniglich Preuss. Regierungs- und Gewerberate for 1912 appeared in the Chemiker-
Zeitung, 37,
1020.
Regarding the strictly medical phases of the sutlject, the following critical comments are made in the hope that they may he suggestive when the book is revised: The intraocular action of certain new alloys which have industrial application, e. g., those of iron with aluminum, nickel, tungsten, chromium and copper, is not mentioned; we are aware t h a t Graham-Rogers regarded ‘‘ brass-founders’ ague” as “zinc poisoning,” but i t is more likely due t o the inhalation of zinc oxide and not zinc fumes (p. 170); until recently only founders were exposed to the fumes of molten zinc or brass, but the perfection of the acetylene-oxygen torch has greatly extended autogenous welding and brazing, and from this “braziers’ disease,” identical with “ brass-founders’ ague,” has arisen; concerning copper (p. 188), Lehmann has shown experimentally that as an industrial poison this metal is not important; in connection with the manufacture of electric accumulators (p. 224), the Regulation of the Secretary of State of Great Britain, dated 1903, should have been mentioned; when lead is temporarily fixed in the tissues, this is later mobilized and i t is likely t h a t it enters the circulation as a soluble lead-protein compound, which might have been mentioned on p. 247 in connection with the occurrence of the lead in the urine in plumbism; Bezzolal has shown that the serious nature of the poisoning is indicated during the period of lead colic by the cytological evidence, although albumin may be absent or present (p. 248); no mention of the“electro1ytic bath” treatment for the removal of lead is made on p. 283 ; no space is devoted to very rare nickel carbonyl poisoning on p. 298, but the very thorough investi.gations of Armit’ were worthy of mention; in regard t o Shuber’s report (p. 299), i t may be observed that argyrosis occurred in the silvering of glass pearls owing t o the introduction of a silver nitrate solution into the beads by mouth-suction-suction pumps are now employed; concerning vanadium poisoning (p. 300)~ Lees3 failed to find that there is any such disease as “vanadiumism” arising from external contact with vanadium compounds; regarding amyl acetate (p. 307), 5 mg. per liter produce irritation of the mucous membranes; cyclohexanol acetate is also of technical importance and 3 mg. per liter produce irritation; the hygienically preferable use of benzine and sulfur chloride for vulcanizing is not mentioned on p. 3 19; it is not noted that carbon monoxide (p. 323) is not widely distributed in the blood poisoned by it, as shown by Wachholz;* diethyl sulfate is not included (p.
.
1 2
8 4
SOL.med. b i d , session June 28, 1913. J . H y g . . 1907, 526: 1908, 565. Enn. M i n . J . . 92, 99. Vinleljahreschr. Ger. Med., 47, 205.
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330) ; carbon tetrachloride, chloroform, and the chlorinated derivdives of acetylene are not referred to; dinitrochlorobenzene. wh:ch causes a violent dermatitis,‘ should have been mentioned on p. 344; concerning roburite (p. 344), in the Witten roburite factory during 1890-7 almost all the workmen had been ill; regarding the prognosis of phosphorus poisoning (p. 354), mention is not made t h a t early operative interference has succeeded in preserving the periosteum which enabled the new bone t o form; regarding Oliver’s views (p. 364), it has been demonstrated that drying paints emit no metallic vapors, although they do produce carbon monoxide;2 it should have been- mentioned on p. 381 that paraphenylenediamine leads to poisoning generally from the use of ursol as a dye, and that its irritant action on the mucous membranes of the respiratory tract is more prominent than its production of kidney inflammation; it is not noted on p. 400 t h a t asphalt dust may cause severe affection of the cornea in workmen exposed thereto, and the full discussions of the lesions produced by the dust and vapor of asphalt in a number of contributions by Truc and Fleig are not referred to; besides wearing a respirator, goggles, a regulation sand blasting helmet, and heavy canvas overalls, leggings and gloves, sand blast operators (p. 418) should be provided with a heavy leather belt, equipped with a snaphook t o engage a ring in a collar near the hose nozzle, t o hold the hose securely and to prevent its getting out of the grasp; ones acquainted with the glass industry in this country state that buccal musculature atrophy and pneumatocele are practically unknown among blowers (cf. p. 409); regarding the effect of siliceous dusts, Rossle3 has recently concluded t h a t laborers in the glass, porcelain, lime and cement industries are relatively favored with regard to tuberculosis; the author differs from Rambousek (p. 443), who considers t h a t “industrial poisoning from tobacco is not proved;” the unpleasant fumes given off during the boiling of linseed oil with oxidizing agents (see p. 462) may also be prevented by closely fitting covers and condensation of the fumes; the action of ultraviolet rays should have been referred to on p. 512; concerning the effects of radium (p. 514), a good discussion of possible injuries is given in Deut. wed. Wochschr., 40, 633, wherein it is shown that handling radioactive substances may cause disturbances of general health, particularly of the blood picture and of the function of the genital glands, besides lesions of the skin; welders should wear aluminum helmets, equipped with combination blue and red glass lens for the eyes (p. 515); it should have been mentioned on p. 570 t h a t Butler’ has shown t h a t chronic carbon monoxide poisoning is one of the principal etiological factors in nystagmus occurring among coal miners; the disease aspects of dermatitis developed when aniline dyes with turpentine or varnish act on the skin5 might have been noted on p. 579; on p. 586 no reference is made t o phenylenediamine, which is widely used in the dyeing of hair or furs and frequently causes eczematous, cutaneous eruptions, which irritant effects are due to a n oxidation product, quinonediimine, and may be prevented by using a sufficient amount of a salt with a reducing action along with the oxidizing agents required for dyeing; Rybak’s elaborate investigations on socalled poisoning by fire-damp are not referred to on p. 612; in regard to ceramic glazing (p. 619), tile-dipping machines are now in use by which handling of the glaze is reduced t o a minimum, and the fettling and cleaning of the glaze from the edge of the tile is practically abolished; Eickmeyer’s study of the injuries t o the cornea by artificial fertilizers6 was worthy of note on p. 633; and on p. 657 the use of alkaline solutions in skinning fruit is not referred to. W. A . HAMOR 1
Bernstein, Lancet, 174, 1534.
2
THISJOURNAL, 6, 9 1 and Drugs, Oils and Paints, 30, 10.
a Milnch. med. Wochschr., 61, 7 5 6 . , Ophlhalmoscope, 1912, 680. 8 See Sachs. Arch. Dermafol., 116, 555. 4
8
Inaug. Diss., Rostock. 1911.
Qct., 1914
T H E J O C R N A L O F I S D U S T R I A L A N D h i V G I L I T E E R I S GC H E J f I S T K E 7
The Electrical Conductivity and Ionization Constants of Organic Compounds. A bibliography of the periodical literature from 1889 to I!IIO inclusive, including all important work before 1889 and corrected to the beginning of 1913. Giving numerical data for the ionization constants a t all temperatures a t which they have been measured: and some numerical data of the electrical conductivity. By HEYWARD SCUDDER, B.A., B.S., h1.D. Pp. 568. New York: D . Van Nostrand Company. 1914. Price, S3.00. The data which are given in this book cover the period of time stated in the sub-title. Since 1910, the ground has been covered by the Tables Annuelles Internationales des Constantes et Donnees Xum6riques. The amount of labor expanded by Dr. Scudder in the compilation must ha1.e been enormous. It is to be hoped that the end attained will justify this and that the book will be used extensively. Twenty-three pages of “Explanation” a t the beginning show the arrangement of the material and give a detailed description of the tables. The tables follow, and then are given Formula Index, Author List, Subject Index, and Journal List. Without having undertaken a careful and detailed study of the tables, i t appears to the reviewer that the work as a whole has been well done. The appearance of the book, including the printing and general arrangement, is excellent. The data will save many chemists much searching through the literature. This book will find its place more and more, as time goes on, covering as i t does a certain field of physical organic chemistry of the past. It should find a place as a reference book in every chemical library. K. G. FALK Chemistry of Dyeing. BY J O H N KERFOOT ~ ’ O O D , D.Sc. New York: D. \-an h-ostrand Company. 1913. 7’1, X 5. Pp. 80 viii. Price, 75c. net. This book is a small monograph giving the present status of the various theories relating to the dyeing process. Without undertaking an extended discussion of the various theories involved, the author has nevertheless given their main points in a very concise manner. He has also criticized the different theories which have been put forward to account for the phenomena of dyeing in an intelligent and conservative manner, The subject is approached from the standpoint of the chemist rather than the technical dyer, and while this book would be of considerable interest t o the general chemist and those chemists who are interested in dyestuffs and dyeing processes, it is doubtful if the manner of presentation of the facts would be of any special interest to the practical dyer. The nature of the dyeing process is discussed as a question in physical chemistry, and of course this is the only proper method of approaching the subject in a scientific manner. The author is unencumbered with preconceived notions and is unprejudiced by any one particular view or theory. Consequently he has given a very fair criticism of the different theories and in a rather impartial manner has suggested a means of bringing the several theories together under one statement of fact. I n order to do this he has had to take a divided view of the dyeing process and instead of regarding it as simple in character and as the result of a single operation, he adopts the view that there are two stages in the dyeing process, the first of which may be called the absorption stage where the dyestuff or coloring matter is simply absorbed from solution, and the second a fixation stage where the coloring matter so absorbed becomes fixed permanently in the fiber which is dyed. In the absorption stage it is probable that the dyestuff is merely absorbed by the fiber by a process of diffusion of the dye solution into the fiber substance and there is no particular theory needed to account for this, i t being entirely governed by the usual laws of absorption and diffusion. Owing to the peculiar structure of the textile fibers this absorption and
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diffusion of the dyestuff solution is slow and k ’ n o t uniformly distributed throughout the fiber but allows of a greater deposit of the dyestuff a t the surface so that the process can lie included under absorption phenomena. As the fibers are considered to be hygroscopic colloids, the manner in which they ahsorh dycstuffs is in accordance with general laws; for instance, all colloidal substances absorb others according to the law embodied in the expression C1, C?v= k , where CI and CB represent concentration in the aqueous and in the other- phase, rmpectively a t the end of the ashorption, k is a constant and u is a constant coefficient. Zacharias has shown that this formula may be deduced mathematically from the laws of diffusion and is applicable not only to the dyeing of textile fibers hut also to other suhstances such as charcoal, aluminum hydroxide, etc. The formula is the same as that representing the distribution of a suhstance between immiscible solvents where homogeneous solutions are formed. The second phase of the dyeing process may bring into play other forces besides those ol a purely physical character. There may be more or less of a chemical reaction involved in the union between certain dyestuffs and fihtir.; or between certain dyestuffs and mordants previously fixed in the fibers. There may be also various physical forces operating in this same connection and a theory of fixation which might l x suitable to explain the action of one dyestuff toward silk for instance, might not satisfactorily explain the action of some other dyestuff towards cotton. Therefore, it cannot be hoped to explain all the processes of the dyeing of all manner of dyestuffs on the various textile fibers by one simple theory. The author gives a t the end of the book a w r y complete hibliographl- referring to the original papers by various chemists on t h e suhject of the chemistry of dyeing. There is one omission to be noticed in the book and that is the work of Prof. Bancroft on the theor>of the dyeing process, but probably this omission ha.; been due to the fact that the matter for the book was written previour to the appearance of Prof. Bancroft’s published work. J. M. MATTHEW The Organometallic Compounds of Zinc and Magnesium. By HENRYWREK,11.A4., D.Sc., PH.D. Chemical LIonographs, No. I , Edited by A4.C. CEMMINGS,D.Sc., F.R.S.E. S e w York: D. \-an Xostrand Company. 1913. Pp. \ i i loo. Price, 75 cents. The latest series of chemical monographs on special subjects of which this \-olume is the first is intended primarily for advanced students. The organometallic compounds of magnesium which comprise the greater part of the book, include the group of reactions discovered by Barhier and developed in so many directions by Grignard. All of the important syntheses are given, together with copious references. The first section ( 1 2 pp.j contains the introduction and the experimental method and precautions to be observed in carrying out the reactions; the second section (60 pp.) describes the various syntheses with the Grignard reagents; the third section i,8 pp.) summarizes some of the theoretical views of the constitution of the reagents and the mechanism of the reactions; while in the fourth section (13 p p . ) the analogous reactions and syntheses with the zinc organometallic compounds are gix-en. A bibliography and index complete the book. The material contained in this monograph will be most useful for the purpose for which it is intended. The general appearance and arrangement is excellent and the size of the volume is very convenient. It can be recommended most heartily to those who desire a concise and fairly complete description of the reactions and reagents in question. K . G . FALK
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Chemistry and its Borderland. BY ALFREDW. STEWART. 8vo. Longmans Green & Co. 1914. Price, $1.25. This book, written for the entertainment and instruction
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T H E J O U R N A L OF IiVDCS2’RIAL . i N D ELVCINEERING C H E M I S T R Y
of the uninformed reader, serves its intended purpose rather more happily than does the typical work of this character. The first three chapters, more or less perfunctory and haphazard, are not a felicitous introduction to the body of the work; but after this rather unsatisfactory beginning, the book takes on a decidedly better tone. The essays which follow are entertaining expositions, written in great part from an historical point of view, and in narrative form on the following topics: immuno-chemistry ; colloids and the ultramicroscope ; the work of the spectroscope; chemistry in space; the inert gases; radium; niton; transmutation ; the nature of the elements ; chemical problems of the present and future. Considering the fact that the author presupposes no chemical knowledge on the part of the reader, these chapters are skillfully written: for, though fragmental, they are consecutive and clear, while the points most emphasized in each discussion are those which are important as well as entertaining. The book is not wholly free from incautious and extravagant statements and conjectures, into which nearly all writers of popular scientific expositions seem nowadays to be betrayed. ;Z statement such as that “in the earlier days of chemistry the atcm of a n element was supposed to be the most minute form of matter which could exist” (p. 2 2 3 ) conveys a false impression, especially when it follows one to the effect that “ t h e discovery of radioactive phenomena has undermined the whole structure of the physics and chemistry of yesterday,” so that “ a t the present time we are hurriedly endeavoring to dismantle the older edifice, while utilizing as much of its material as is suitable in the construction of a more modern erection” (p. 214). Such a statement is not only exaggerated. but is essentially false. One might have hoped, also, not again to have encountered in a book which will be read by many as authoritative, the definite and unqualified conjecture that the energy oi radioactive disintegration may one day supplant that of our present coal supply (p. 2 3 3 ) nor the anticipation that the synthesis of pclyFeptides even remotely points to the subsequent creation of lix-ing protoplasm (p, 246). However, such remarks are rare in this book and seldom mar the quality of a generally wholesome and very entertaining group of essays The chemist reader will be interested in the chapter on transmutation, in which the author supports with lively argument the contention that the recent experiments of Collie, Patterson and Rarnsay demonstrate the synthetic transmutation of the elements. The last two chapters are an effective appeal to the public a t large for the more intelligent support of scientific investiga-
tinn Though the need for such appeal is, happily, not as urgent here in America as it probably is in England, correct information nevertheless, concerning the supreme pi actical value of pure scientific research and the best practical means for its encouragement, cannot be too widely disseminated. F. BARRY
The Silicates in Chemistry and Commerce. BP IT. ASCHAND D . ASCH. -\, B. SEARLE,Translator. Yew York: D. Van Sostrand C o . 456 pp. Price, $6.00. The present volume under its promising title represents the e l a h r a t i o n of a thesis having for its object the consideration of a general theory of the structure of silicates analogous to the systems of organic chemistry. The first two sections give an excellent historical review of exi-ting theories concerning the structure of silicates and their critical examination. I n the following sections their new theory is advanced, according to which two types of Si and A I radicals are supposed to exist. The one type supposes the union of six molecules of Si(OH)4, and similarly of six molecules of Al(OH), vr.hich unite to form closed rings, maintaining the tetra- and tri-
1‘01. 6, KO.
Ia
valencies of Si and Al. These complexes are called hexites. Similarly, by the combination of five molecules of Si(OH)a, and five of Al(OH)a, respectively, the closed ring radicals. to be known as pentites are formed. These radicals provide the nuclei for the acids and anhydrides. “ T h e A1 hydrohexites or hydropentites unite with those of silica and vice tlersu, the hydroxyl groups in the ortho position in these rings splitting off the elements of water, two other OH groups, also in the ortho position of the silicon ring, losing their hydrogen atoms and forming free H20.” Types consisting exclusively of hexites are termed primary, those containing both hexite and pentites are secondary. The analogs of the benzene ring are then carried out step by step down to base and ring isomerism. Thus, as an illustration of the latter case, orthoclase and microcline are cited. The theory is extended to molybdic and tungsten complexes. I n the discussion of the structure oi clays the authors assume the formula 6H?0.6Al& 1 2 S i 0 ~for kaolins and maintain the existence of two kaolinic acids, a and s, according to whether they possess central A1 or Central Si rings. The authors even predict the plasticity of these kaolinic acids, claiming that the a type is more plastic owing to the greater content of water of constitution. I n applying the hexite-pentite theory of clays to various phenomena, the writers make many statements not in agreement with known facts. .kccording to them, clays are not mixtures of “clay substance,” feldspar and quartz, but are of unitary structure. The translator does not help matters by introducing supplementary notes utterly irrelevant to the question of the constitution of clays. Occasionally he saves the day by correcting such a statement as: “Vitrified clays must hc more easily attacked by acids than unvitrified ones.” The discussion is extended to ultramarines. Portland cement, slags. dental cements, glasses and glazes. The treatment of some of these subjects might he termed weird. We learn, for instance, that Portland cements are single hexitepentite compounds and not mixtures and that the tri-calcium silicate is a purely hypothetical compound. Considerable a t tention is given to dental cements from the h. p. standpoint and even their physiological hehavior is discussed. Definite formula arc assumed for many glasses and glazes, a procedure surprising to ceramists whose experience tends to support the T-iew of silicate mixtures. Other topics treated are those relating to water of crystallization; the dissociation theory: the constitution of simple acids: the h. p. theory and carhon compounds: the Airchidhypothesis; the h. p. theory in stereochemistry with reference to di- and polymorphism and isomorphism: optical properties, etc. In a summary, reply is made to various critics oi the German edition. Any attempt to bring unity into the coniusion of the xGws relating to silicate structure is to he welcomed. In so far as the statement of their hexite-pentite theory is concerned, the authors deserve a respectful hearing. They cannot be expected to produce complete proofs for their assumption, considering the enormous difficulties offered by laboratory research along these lines and the comprehensix-eness of their fundamental statement. On the other hand, the proofs cited h y them hascd on the work of others are open to serious doubt and the evident inaccurac>- of many statements does not encourage confidence in the conclusions. The present writers w ~ u l dhave fared much better had they tested their theory by the critical examination oi a small number of typical silicates instead of endeavoring to explain in a wholesale manner ex-ery kind oi fact relating to silicates. For the reader who desires to secure sound technical information concerning silicates the hook is of no value. A . Y. BLEIXIKGER
