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37 J. Crim. L. & Criminology 346 (1946-1947)
Police Science Technical Abstracts and Notes

handle is hein.journals/jclc37 and id is 354 raw text is: POLICE SCIENCE TECHNICAL ABSTRACTS AND NOTES Joseph D. Nicol* A New Light Source for the Laboratory. A description is given in a paper written by W. D. Buckingham and C. R. Deibert, published in the May issue (Vol. 36:245-250) of the Journal of the Optical Society of America, of work done at the Western Union Telegraph Company on a concentrated arc source. In a spot .003 inches in diameter a bright- ness of 100 candle per square mm. is attained. This is accomplished by making a specially prepared cathode the source of light. Lamps have been made in the following wattages: 2, 10, 25 and 100, with life spans in the hundreds of hours. The radiation emitted covers the spectral range of 2500A to 10,000A. The brightness of the arc may be adjusted by controlling the current. Intensities approach that of the carbon arc. Special powers supplies are needed consisting of a starting high poten- tial and the running potential. These may be operated from a 110 volt source. The lamp burns quietly with uniform brightness with no need of adjustment. As a point source it has use in photography, lensless projection, studies in oblique lighting of indented writing, etc. More elementary treatments with the applications to photography emphasized may be found in the following publications: U. S. Camera, 9:13, 50, 67 (May, 1946); U. S. Camera, 9:25,51 (June, 1946); Popular Photography, 18:74, 122 (June, 1946). A Test Paper Holder. In order to eliminate contamination in gas analysis and permit acid or alkali cleaning, E. B. Parks has designed a test paper holder for all glass construction. This he describes in The Analyst, 71:287 (1946), with diagrams enabling the duplication in any lab. equipped With a few tools for glass and metal work. The design is simple. Carbon Monoxide in Blood. In the Analyst of March, 1946 (71:107- 10) a method is described for the rough estimation of carbon monoxide in blood samples using quantities as small as 0.25 ml. The analysis as given by C. H. Gray and Marjorie Sandiford in A Micro-diffusion Method for the Estimation of Carbon Monoxide in Blood may be done either by absorptiometry or colorimetry. Volatile Saturated Fatty Acids. The use of fatty acids in the range from propionic to valeric acids as components of stench bombs makes a means of separation and identification of these acids necessary. An article on Separation and Identification of the Volatile Saturated Fatty Acids by L. L Ramsey and W. I. Patterson in the Journal of the Association of Official Agricultural Chemists, 28:644-656 (1945), relates a method applied in biological research. The analysis makes use of chromatographic adsorption on a silica gel column using 1% butanol in chloroform as the solvent. Brom cresol green is used as. the indicator. The separated acids are then identified by standard tests. he procedure and identifying tests are described for amounts less than 2 ml. of N/10 acid. The Use of the Police Club. Various methods for the use of the police club are suggested by Wesley Brown, Jr., In Defense of the Police Club *Firearms Identification Technician, Chicago Police Scientific Crime Detection Laboratory.

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