An improved spectrographic source

Abstract

ConclusionsI. Fatty substances are zeadily decomposed in the compost ; 75% of fatty substances, in the presence of small amounts of S/A, are decomposed in the first fortnight of composting.2. The rate of decomposition of fatty substances in the compost heap is very similar to that observed under laboratory conditions.3. Saponification values f d very rapidly on composting. In the presence of S/A this decrease is more rapid, and the 6nal saponification value is lower than in the absence of S/A. 4. There is no indication in the compost of the synthesis of fatty substances by micro-organisms.The requirements for n spectrographic source of stable characteristics are discussed and a circuit is then described which fulfils these conditions. The circuit has been tested by analysing numerous samples ofa strong alloy to Specification 5L3, and of pure aluminium, and the standard deviations of the results indicate that it is a substantial improvement over the condensed spark source normally employed. A brief discussion of the processes in the analytical gap as they affect choice of circuit conditions, and of the considerations involved in the selection of spectrum line pairs for use in analytical spectrognphy concludes the paper.At the present time, and using equipment commercially available in this country, the application of the spectrographic method is somewhat limited because of the magnitude of its errors, which sometimes compare unfavourably with those of the orthodox chemical procedures. In addition, in its present state of development in Britain, it does not appear to be capable of dealing economically with aluminium alloys containing constituents present in excess of I-I#%.With a view to improving the accuracy of the method, and thus increasing the range of its application, the work described below on the development of a stable discharge source of controllable characteristics has been carried out.