The aim of this work is to investigate the use of degenerate four-wave mixing (DFWM) as a probe for measuring temperatures and species concentrations in hostile environments. 1994 was the first year of the project. A hydrogen cell Raman-shifter was coupled to the 248nm output of a narrowband KrF excimer laser to use as a high intensity tuneable source for the DFWM experiments. First order anti-Stokes radiation at 225nm was observed and laser-induced fluorescence (LIF) was performed on the nitric oxide molecule at room temperature in a cell to confirm that the tuning capabilities of this modified laser system was suitable to probe NO resonances. Some excellent results were acquired due to the smaller laser linewidth obtained from the use of a grating in the laser oscillator. LIF excitation experiments in NO were also performed in an hydrogen-oxygen flame. Recently, we have performed DFWM in a H2/O2 flame, using an Excimer-Pumped dye laser at 226 nm. After performing some temperature measurements in a flame, we will attempt to apply DFWM to a practial shock-tube flow.