Abstract
The relative intensities of a group of ten lines of the spectrum of a hydrogen discharge tube have been measured both by conventional photoelectric densitometry and with a logarithmic sector. A statistical analysis of the results showed that, for our instruments, photoelectric densitometry is slightly more accurate than logarithmic sector intensitometry; the former method gave an average coefficient of variation, in the measurement of an intensity ratio, of 2% whereas the latter method gave an average coefficient of variation of approximately 4%. However, for a great many applications in spectrochemical analysis the latter method appears to be sufficiently accurate, at the same time having many advantages. It is faster, simpler; intensity ratios are obtained directly without the need of a calibration curve; the method is self calibrating; it does not involve a considerable amount of complicated equipment that requires frequent attention; intensity ratios can be made over a much greater range for a single exposure of the spectrum.
Get full access to this article
View all access options for this article.