I N D U S T R I A L A N D ENGINEERING CHEMISTRY
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1 ‘
gives a pattern with the copper lattice practically identical with the supposed lattice of a silver-rich solid solution with the K, radiation, and there is little doubt that Drier’s conclusions are erroneous. CYRILSTANLEY SMITH RESEARCH LABORATORY AMEFUCAN BRASSCo. WATEREURY CONN. June 15, 1831
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Editor of Industrial and Engineering Chemistry: It is possible that, as Mr. Smith suggests, the spectral lines attributed to silver are due to a MoKB reflection from the copper lattice. It is more probable that the spectral lines are partially due to such cause, inasmuch as the x-ray spectrum of spectroscopically silver-free copper gave no evidence of the silver lattice. It is an unfortunate coincidence that a MoK, reflection from a silver lattice and a MoKb reflection from copper coincide so closely. At the time the work was done, molybdenum radiation was the only one available, for otherwise some other radiation would have been used in corroboration. Mr. Smith refers to Stockdale as being in direct disagreement with my conclusions. I n the paper by Stockdale referred to, Stockdale concludes, “ . . . . .at room temperature silver is almost insoluble in copper.” Mr. Smith, in “Constitution of Copper-Silver Alloys,” a paper prepared for the Nonferrous Data Sheet Committee of the Institute of Metals Division of the American Institute of Mining and Metallurgical Engineers, refers t o Hirose who states that the solubility of silver in copper decreases rapidly to a negligible amount at 500’ C. Manifestly, if it is negligible at 500” C., it is still less soluble at room temperature. In the same paper Smith states “both Erdal and Weinbaum have determined the solubility (of silver in copper) from crystal structure measurements but their results are not convincing.” This is the same reference he uses in criticizing my manuscript. The writer appreciates Mr. Smith’s critical efforts, but in view of the vast disagreement of the literature cited they do not seem t o be a t all conclusive. ROY W. DRIER DEPARTMENT OF METALLURGY MICHIGAN COLLEGE OF MININGAND TECHNOLOGY HOUGHTON, MICHIGAN July 2, 1931
Editor of Industrial and Engineering Chemistry: On page 710 [IND. ENG. CHEM.,23, 708 (1931)], Elizabeth W. Aldrich and Dale W. Querfeld say that “the boiling points of ethanol solutions are somewhat higher than those of methanol solutions having equal freezing points.” This statement is incorrect when speaking of solutions having freezing points between 0 ” and -15’ C. The data contained in this article are no doubt quite accurate, since, as the authors have indicated, they agree very well with other literature on the same subject. The error is that the abovementioned statement is not corroborated by either the prior literature or by the article in question. The following abbreviated table may be formed by making a few additions to Table 111, page 710 from data contained in Tables I and 11:
c. -5
- 10 - 15 - 20 etc.
ROILINGPOINT
Methanol-Water 0
c.
92.0 88.2 86.0 84.0 etc.
Ethanol-Water 0
These data vary slightly, depending upon the literature used as an authority, but in general it can be said that the boiling points of aqueous ethanol solutions are lower than those of aqueous methanol solutions having equal freezing points, when the freezing points are between 0’ and -15’ C. If the freezing points are below -15’ C. (+5’ F.), then the boiling points of ethanol solutions are higher than those of methanol solutions which have the same freezing points. R. J. KEPFER CHEMICAL DEPARTMENT DU PONTAMMONIA CORP. WILMINGTON, DEL. June 11, 1931
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Editor of Industrial and Engineering Chemistry: Mr. Kepfer is correct in stating “that the boiling points of aqueous ethanol solutions are lower than those of aqueous methanol solutions having equal freezing points, when the freezing points are between 0’ and -15’ C.” The original statement t o which exception has been taken was intended to refer to solutions of such concentration as are normally used in antifreeze mixtures, and hence reference was not made to solutions having freezing points above -15’ C. ELIZABETH W. ALDRICH BUREAU OF STANDARDS WASRINGTON, D. C. July 7, 1931
Heat Transmission to Water Flowing in Pipes Editor of Industrial and Engineering Chemistry: A. E. Lawrence and T. K. Sherwood [IND.ENG.CHEM.,23,301 (1931) J state that the power of cz/& was found t o be 0.5. Our exhaustive research checks this value exactly. There is an indication that the power of c z / & gradually diminishes as the value of this modulus increases. It is possible that the value 0.37 which has been observed by many investigators is merely a result of a n average. Lawrence and Sherwood state that tube length has only a very slight effect on f ilm coefficients. Their conclusion may be correct in their particular tube sheet assembly for a single-pass tube. However, in a commercial multi-pass exchanger, there is d turbulence factor expressed by McAdams and Frost as (1 50/r), and substantiated by our research, which clearly indicates that film coefficients inside tubes vary inversely as a power of the tube length. No mention was made as to the type of solder used in their thermocouple junctions. We have encountered difficulty with copper-constantan thermocouples with soldered junctions a t temperatures above 175” F. (79.44’ C.). Any solder containing lead, zinc, and tin alloys undergoes a change in state a t about 185”F. (85’ C.) or higher, which would make the use of solder in this case questionable. We wish to agree with these investigators in that there is no discrepancy between the heating and cooling coefficients such as reported by Stanton, and Morris and Whitman. Our research involved an exhaustive series of tests covering steam to oils, oil t o oil, water to oils, steam to water, water to water, steam to air, and water to air. L. J. COULTHURST L. P. SCOVILLB
+
Freezing and Boiling Points of the Ternary System EthanolMethanol- Wa ter
FREEZING POINT
Vol. 23, No. 8
SOUTHWESTERN ENCINEERIKG CORPORATION 4800 SANTAFE AVE. Los ANGELES, CALIF. June 2 2 , 1931 ..............
c.
91.1 87.8 86.0 84.8 etc.
Editor of Industrial and Engineering Chemistry: The comments of Coulthurst and Scoville substantiating the use of the exponent of 0.5 on the c s / k group are indeed gratifying.
August, 1931
I-VDUSTRIA L A.VD ENGINEERING CHEMISTRY
Our own data covered such a small range of variation of this group that the indication of an exponent of 0.5 was by no means conclusive. The writers do not state whether the length effect found in the commercial multi-pass exchanger was with oil or water. Although our data show no effect of length for water, we were careful to state that an effect of length might be found when heating an oil. This has been borne out recently by data which we hope will form the basis of a future publication. The solder used on the thermocouples was ordinary solder as used in electric work and was not analyzed. It is not clear how a change in state in the solder, if such occurs, could be expected
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to influence the reading of a thermocouple when using a potentiometer. An extremely small amount of solder was used a t the junction, and it would seem that as long as the solder remained a good electrical conductor, errors would not be expected. We note with interest that Coulthurst and Scoville have concluded an exhaustive series of tests on heating and cooling oils, water, and air. It is to be hoped that these much-needed data will be published a t an early date. THOMAS K. SHERWOOD DEPARTMENT OF CHEMICAL ENGINEERING MASSACHUSETTS INSTITUTE OF TECHNOLOGY CAMBRIDGE, MASS. July 6, 1931
BOOK REVIEWS The Manufacture of Artificial Silk with Special Reference to the Viscose Process. BY E. WHEELER. 2nd edition. 176 pages. D. Van Nostrand Company, Inc., New York, 1931. Price, $5.00. This is a second edition of the work under a similar name which appeared in November, 1927. In the preface t o the first edition, the author says, “The present monograph cannot claim to be an exhaustive treatise on the subject, but its object is to provide a description of the essential chemical and engineering details of the modern methods of manufacturing, and of the properties and uses of artificial silk.” In this brief statement the author well outlines the contents of the book. A short historical introduction is followed by a brief discussion of the four standard processes for the manufacture of synthetic fiber. The next three chapters are devoted to the viscose process; two chapters take up the cuprammonium process; and one chapter each is devoted to the nitrocellulose process and the cellulose acetate process. Brief mention is then made of five processes which have been suggested but have never proved commercial, after which there are two chapters devoted t o the properties of synthetic fibers; one chapter to uses; and one on other artificial fibers such as synthetic wool, staple fiber, and artificial straw. A brief consideration of the economics of artificial silk production is then presented, and a description of laboratory methods for controlling the manufacture and testing the product conclude the work. It is too much to expect so short a book to go into intimate details, but the author has succeeded in presenting an accurate picture of the manufacture of the various synthetic fibers. In some slight details he is not entirely up t o date, as, for example, in the chapter on nitrocellulose where no mention is made of the modem method of dehydrating with alcohol. Also, in the chapter on properties no reference is made to the developments of the last few years in increasing the strength of viscose rayon. The illustrations are numerous and of an excellent character and there is a very good index. The book is to be recommended to anyone not familiar with the rayon industry who would like to obtain an idea of the various ways in which rayon is made and the JR. properties of the resulting products.-GusTAvus J. ESSELEN,
for which many virtues are claimed by the manufacturers are treated impartially by the author. Flue gas tells an important story if given a chance, and several varieties of instruments are compared which will provide the opportunity. The reader may even essay a comprehensive boiler test, for an outline of instructions is provided in one of the later chapters. In all, thirteen chapters of worth-while information are provided for him who must run while he reads. It will be apparent from the foregoing that the book offers little to the chemical specialist who is interested in the scientific minut i a of some one or two of the several phases treated here from a practical standpoint, nor is it intended by the author to serve more than the stated purpose. It is the outcome of practical experience gained in the service of two English railways. While written principally from the viewpoint of English practice, reference is made t o the current American and continental literature to an extent compatible with the scope of the book. Freedom from typographical errors is noteworthy. For the heat of combustion of one pound of carbon t o carbon dioxide, different values appear on pages 180 and 192, respectively. The king’s English is honored occasionally in the breach rather than in the observance, but this somewhat improves, rather than detracts, from the practical flavor.-L. B. HITCHCOCK The Psychology of the Inventor. A Study of the Patentee. BY JOSEPH ROSSMAN.252 pages. The Inventors Publishing Company, 1266 New Hampshire Avenue, Washington, D. C., 1931. Price, $3.00.
This book, which is an unusual effort upon a previously but little-treated subject, is of much interest and will be found so not only by the scientific worker and engineer, but by any layman who is interested in the development of his country, and even more broadly, in the development of civilization. The work is properly subtitled “A Study of the Patentee,” as the author has based it upon his experiences as an examiner in the United States Patent Office and upon f i s t hand information obtained from a group of over seven hundred inventors. The informatioil so obtained was supplemented by five hundred questionnaires sent to outstanding patent attorneys in the United States The Chemical Technology of Steam-Raising Plant. BY HENRY and three hundred questionnaires sent to the directors of research A-ORYAN BASSETT. 240 pages. Longmans, Green, and and development departments of the largest corporations and companies in this country. Company, New York, 1931. Price, $5.00. The development of the subject is logical and the reader’s interFor the power-house engineer who has had little or no chemis- est is maintained throughout. In fact, the reaching of the end of try, this volume describes in logical sequence the various prob- a chapter finds the reader desiring that the matter being treated lems of a chemical nature with which he should he reasonably be continued. It would be of interest, if space permitted, to summarize briefly each of the chapters, but this is not possible, and conversant today. Chemists will agree with the author that steam-plant management may be materially improved with the hence only the chapter headings will be given with the hope that these will denote somewhat the character of the material discussed: assistance of chemistry, but not all power-house engineers have fully accepted this fact as yet, it is feared. This book, by its I-Civilization and Invention; 11-What Is Invention? ; IIIpractical style and readable descriptive treatment, will do much to Classes of Inventors; IV-The Characteristics of the Inventor; V-Actual Methods of Inventing; VI-The Mental Processes of convince the doubting Thomases if there be such. For steam engineers who believe in chemistry but are embar- the Inventor; VII-Chance and Accident in Invention; VIIIrassed by their ignorance of chemical terminology, this work intro- Multiple Invention; IX-The Occupation of the Inventor; duces in language as non-technical as possible such interesting X-The Motives of Inventors; XI-Obstacles and Pitfalls of aspects of steam generation as the geology of water supplies, Inventors; XII-Heredity and Invention; XIII-Psychological water-softening processes, causes and prevention of scale and Theories of Invention; XIV-Tfaining Inventors; and XV-The corrosion, fuel analyses, and the performance of furnace linings Psychology of Patent Law. and other materials of construction. Commercial preparations The author’s information received from inventors included
