Modification of the Beckman Spectrophotometer with External C Battery Supply and Voltage- Checking Arrangement SIR: In the March issue of A~L~LPTICAL CHEMISTRY [25, 534 (1953)l a modification of the Beckman spectrophotometer a i t h external C battery supply and voltage-checking arrangement 15 given by L. P. Cecchini and Maynard Eicher. This exteinal rupply eliminates the cumbersome inversion of the instrument when the batteries are to be replaced or checked, or when the screen voltage of the 2532 tube is to be altered. I t allows as well checking of the voltages appearing at the terminal strip inside the instrument. An inspection of the wiring diagram of the Beckman spectrophotometer shows that the anode voltage of the 2531 tube is supplied by batteries 3 and 4, but that 3 volts more are taken from battery 2. This means that the latter battery is, in part, conimon to both the photocell and the second stage in the amplifier. I n constructing a power source for the Beckman Dt- spectrophotometer the Fisher Go. [The Laboratory, 22, 118 (1953)] has included a seventh C battery giving the 3 volts more, which are needed for the anode voltage of the 2531 tube and thus removing any possibility of interaction betwreen the amplifier arid the photo detection circuits. The company claims that this modification is recommended by Beckman. When constructing external C battei j supplies according to Cecchini and Eicher I therefore included a seventh C battery. It was connected in series with battery 3; its negative pole connected to that of battery 2 and both to thP seventh terminal of thr selector switch [ J . Opt. SOC.Amer., 31, 682 (1941) {Figure 5);. This is shown in the wiring diagram,’where A shows the oiiginal connection and B the inclusion of the seventh C battery. A double-pole eight-position switch was also connected to the battsries for convenient check of their voltages 113th the aid of a double-pole-double-throw switch a 600-ohm resistor could be
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Inorganic Chromatography. Orsino C. Smith. viii 131 pages. D. Van Nostrand Co., Inc., 250 Fourth .ive., Ye17 York, N. Y., 1952. Price, $5.00. This book is divided into two parts, “History and Theory” and “.-ipplication.” According to the author, “The attempt to apply ohromatography to the analytical groups was carried out before any review of the literature xas made. This was donr purposely so that the past work of others would not influence the author in his endeavor, thus leaving him with a free, unbiased mind.” This would hardly be considered the most profitablc approach to a problem by most research investigators. Part I consists of the introduction (Chapter 1) and abstracts of articles on chromatography (Chapters 2 to 7). The introduction is very incomplete. S o n e of the recent important literature contributions regarding the theory of selectivity or behavior ot substances in column operations was considered. Recent review articles and books on chromatography and related topics were entirely ignored.
connected in parallel during thc, measurement. The eighth position 11as left empty and the switch is kept there in order to avoid discharging any of the batteric? over the 600-ohm resistor by mist akr ,
f
*2
II
f07
*7
II
*3
I
In Sweden the Burgess 5540 batteries are fairly expensive because of transportation and duty. I have therefore replaced them with batteries of Swedish make with about double the capacity. The drain being very small, I hardly expect any lengthening of the service life, but the instrument has become inore stable, perhaps because of the increased capacity or the zeventh C battery or both.
KKE S:SOX
STENIU~
Swedish Forests Products Research Laboi 1tory,
Stockholm, Sweden
The abstracts are, in the opinion of the reviewer, about equal in value t o a reader to a similar collection of abstracts from Chemzml .2bstracts. The headings of the chapters in which these abstracts appear seem to have been chosen rather arbitrarily. Chapters 4, 5, and 6 consider topics sufficiently different to warrant separate headings, Chapter 7 should be included with Chapter 6 , because, chemically, the separation of radioactive tracers by ion exchange is no different from t h a t of stable isotopes of t,hesame elements. The order of presentation of the abstracts within each chapter is neither chronological nor based on any other system discernible to the reviewer. Only a small fraction of the articles published in this field have been abstracted. In some cases, important articles are dismissed with a single sentence or short paragraph, while less important articles, mainly of historical significance, receive much more thorough presentations. The references in the bibliography are arranged neither alphabetically nor in the order in which they appear in the text. The author index refers to 1572
