mediate contact with important and relevant instrumental applications. This approach is executed very well and will appeal to many readers. To some others, especially the beginner in the laboratory, there is a trade-off of problems. For example, the operational amplifier is used in Module 1, whereas the principles of amplification and operational amplifiers are not introduced until later in Module 2. Thus, in return for early establishing the relevance of a real device, the beginner must use the device as a "black box," for which little feeling or understanding is possessed. A unique modular format provides the series in four, inexpensive paperback forms either with detailed experiments or with laboratory summaries. In addition, the entire series is available as a hardbound text/reference with laboratory summaries. Together, Modules 1, 2, and 3 comprise a contemporary course in analog and digital electronics, combined with transducers and major concepts of instrumental, scientific measurements. Modules 3 and 4 especially reflect the 'state of the art' and are excellent reference books for capable scientists while still being understandable for the beginner, providing time is available for careful reading. The introduction to electronic instrumentation in Module 1 presumes little background in electronics and is written clearly and understandably. The basic concepts of charge and current are made immediately relevant by studying familiar transducers having current outputs. A similar approach is followed with voltage source transducers. Modern null measurements, as illustrated by servo measurement systems, completes the first Module. Module 2 begins with a study of circuit elements including resistors, capacitors and inductive devices, and their uses in measurement and control. The section on electronic switching includes an excellent summary of the mechanisms of conduction at junctions. For example, the review of metal-metal junctions including contact potential, thermal potential, and thermoelectric effects with and without currents provides in a few pages information that is generally scattered among a variety of references. The presentation of power supplies, amplification and automatic feedback control has been extensively updated and modified from the earlier presentation in "Electronics for Scientists," resulting in greater clarity, depth, and relevance to the experimentalist. Module 3 treats the encoding of data in the three electrical data domains: analog, time, and digital. The characteristics of signals in these do-
mains are developed first, followed by many applications in scientific instrumentation. The organization concepts are new and are helpful in putting order into an otherwise bewildering array of modern digital instrumentation and measurement techniques. The optimization of electronic measurements is studied in Module 4 by consideration of techniques for improving the signal-to-noise ratio of electronic measurements. These include control of frequency response via analog filters and modulation/ demodulation techniques. The problems of sampling a time varying continuous analog signal and the proper choice of sampling parameters are related to optimization. Finally, the most up-to-date enhancement techniques, including lock-in amplification, boxcar integration, multichannel integration, and correlation techniques, are discussed. The experimental sections are difficult to review meaningfully, since many users will have to modify the experiments to match the laboratory facilities available. We have found the directions generally clear and explicit, with helpful schematic diagrams. The addition of a Table of Contents of Experiments would be useful. The experiments causing the most trouble were those which used unspecified components, such as LED's, photoconductive cells, etc. These experiments could be written so that the student could check the performance of the components and determine whether they passed the required specifications before using them in complicated circuits, so often requiring extensive debugging. The operational amplifier experiments are written for use only with the expensive $10 to $50 variety operational amplifiers. Most could just as easily have been written for the inexpensive 741 variety, thus significantly lowering the cost of replacing blown amplifiers. Instructors will find grading the laboratory writeups awkward, since the text needed by students for study and the laboratory worksheets needed for grading are in the same book. The entire contents of the four modules would best be studied over an academic year. Many instructors having available only a single quarter must skip interesting and important sections to achieve the desired course breadth. Despite making the reading a bit choppy for the student and placing added responsibility on the instructor for topic selection and smoothing the transitions, the great diversity in content and up-to-dateness of the book add to a resounding plus. The many illustrative problems, together with their solutions, are particularly useful for self-study. For graduate students
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Books whose researches will often require designing and using advanced instrumentation, the portions of the text treated lightly in a course will prove to be gold mines of information long after the formal course has ended. There is little doubt but that "Electronic Measurements for Scientists" will find a place on the bookshelves of most scientists, alongside their wellworn copies of "Electronics for Scientists."
New Books Official Methods of Analysis. Twelfth edition. William Horwitz, Ed. xxi + 1094 pages. Association of Official Analytical Chemists, P.O. Box 540, Benjamin Franklin Station, Washington, DC 20044. 1975. $40 ($41 foreign)
This book contains analytical methods, validated by collaborative studies in laboratories throughout the world, for agricultural products, foods, beverages, drugs, cosmetics, color additives, and other commodities important in public health. New in this edition is a chapter on forensic sciences which includes tested methods for the examination of glass fragments and fingerprints. Human drug methods have been subdivided into five new chapters classified primarily by chemical properties. Some older methods no longer in general use have been removed so that more rapid and sensitive assays could be included. Among these are automated methods for drug analysis, dairy products, and fertilizers, and atomic absorption spectrometric methods for lead in paints, aluminum in baking powder, cadmium and lead in various foods, and nine minor elements in water. The chapters on natural poisons and isolation of extraneous materials, e.g., filth elements such as insect parts and animal hairs, are substantially larger. This edition also contains a series on methods developed by EPA for the examination of waters, eight pesticide formulations methods jointly approved by AOAC and CIPAC (Collaborative International Pesticide Analytical Council Ltd.), and a number of new pesticide residue methods sensitive to the nanogram level. Although not specifically prescribed by law, the methods of the AOAC have long enjoyed status in the courts and are relied upon by regulatory agencies of federal, state, provincial, and municipal governments, the regulated industries, and research workers in agriculture and public health. Approved methods are given official
Books sanction at the AOAC's annual meeting and are published first in the Journal of the Association of Official Analytical Chemists and then collectively in "Official Methods of AnalyConcise Chemical and Technical Dictionary. Third edition. H. Bennett, Ed. xxxix + 1175 pages. Chemical Publishing Co., Inc., 200 Park Ave. South, New York, NY 10003. 1974. $35
About 75,000 definitions are included in this volume which covers every field of scientific and technical development. The nomenclature in this dictionary is that generally adopted by the chemist and the engineer. Thousands of cross-references are included and arranged so that the desired terms can be located with a minimum of effort. A special feature is an up-to-date compilation of thousands of trade name or proprietary products in the synthetic resin, plastics, metal, rubber, textile, food, pharmaceutical, and paint and varnish fields.
Computers in Analytical Chemistry (with emphasis on chromatography). 170 pages. Friedr. Vieweg & Sohn, Verlagsgesellschaft m.b.H., D-3300 Braunschweig, West Germany. 1974. DM 60
This special issue of Chromatographia (Vol. 7, No. 9) includes the papers presented at the International Symposium on Computers in Analytical Chemistry held in Vienna, Austria, September 24-27,1974. The focus is on applications of computers in chromatography and those methods which are often used in combination with chromatography. General topics include computer systems for the laboratory, data acquisition and refinement, documentation and interpretation of analytical information, microprocessors, and control of experiments.
Continuing Series Encyclopedia of Industrial Chemical Analysis, Vol. 20. Foster Dee Snell and Leslie S. Ettre, Eds. xL + 679 pages. John Wiley & Sons, Inc., 605 Third Ave., New York, NY 10016. 1974. $50
This final volume of the "Encyclopedia" gives the contents of volumes 1-19 by title and authors, an alphabetical listing of contributors, and a
general subject index of volumes 4-19. The index of the first three volumes dealing with general analytical techniques can be found at the end of the third volume. Analytical Calorimetry, Vol. 3. Roger S. Porter and Julian F. Johnson, Eds. xii + 818 pages. Plenum Publishing Corp., 227 West 17th St., New York, NY 10011. 1974. $45
The contributions to this volume represent papers presented at the Third Symposium on Analytical Chemistry held at the 167th National Meeting of the ACS, March 30 to April 5,1974. Topics include discussions of identification of polymers and inorganic materials by thermal analysis, applications in forensic science, kinetic reaction studies, and quality control applications in industry. The text is reproduced from typed copy. Guide to Gas Chromatography Literature, Vol. 3. Austin V. Signeur. ix + 1089 pages. Plenum Publishing Corp., 227 West 17th St., New York, NY 10011. 1974. $65
Volume 3 of this series provides exhaustive coverage of the literature from 1967 through late 1971 and contains 15,471 references and authorsubject indices.
The Eberbach Shaker Bath Table Model finds many applications in the fields of microbiology, biochemistry and chemistry. It provides continuous duty shaking in the range of 0 to 350 strokes per minute. The mechanical transmission assures constant speed in spite of variation in line voltage or in load. Temperature of the bath can be controlled from ambient to 80°C plus or minus 0.5°C. Temperatures above 80°C can be obtained with an accessory auxiliary heater and gable type cover. For controlled atmosphere applications an accessory hood is available. Immersion depth is controlled 3 ways; adjustable carrier, adaptors and water level control. Stainless steel flask carrier is 14 by 10 inches. Cat. No. 6250 priced at.
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484 A · ANALYTICAL CHEMISTRY, VOL. 47, NO. 4 , APRIL 1975