The Babington principle nebulizer, useful for the introduction of samples containing suspended solids, or having high viscosities, into flames or plasmas, has been developed and characterized. Smaller versions of the nebulizer have been shown to provide higher sensitivity and reduced memory relative to the larger devices used previously. Data showing the sensitivities observed with a Babington type nebulizer and a flame emission spectrophotometer at varying flow rates of both the nebulizing gas and the sample solution are presented, along with an evaluation of several nebulizer configurations and tip sytles. The effect of nebulizing gas orifice size upon sensitivity is discussed. Although the Babington principle nebulizer will tolerate samples of varying viscosity, the nebulization efficiency is affected by the sample solution viscosity. A Babington type nebulizer employing a sample heater has been constructed and evaluated using motor oils of differing grades, and has been shown to reduce the effect of viscosity for this class of samples. This heated Babington type nebulizer has been used to develop a method for the analysis of wear metals in oil which does not require sample pretreatment. The effect of polymeric viscosity index improving additives commonly added to motor oils on the sensitivity of the method has been explored, as well as the effect of different complexing agents which may be used in the preparation of standards. A new method is described for numerically evaluating the inverted Abel integral equation, used to extract information about interior regions of flames and plasmas from spatially resolved data obtained from side-on measurements. This method, based upon cubic spline approximations, is compared to modifications of two methods drawn from the literature over a range of data set sizes and with varying amounts of noise superimposed upon the signal. The results of this study give a basis for selecting the best method for transforming experimental data of varying quality, and also for estimating the reliability of the results of the computation. An appendix describes the design and development of an instrument, computer interface, and software package which allow spatial mapping of spectroscopic sources at high speed. Suggestions are given for future work in these areas.