Abstract : A variable-temperature FALP/SIFT apparatus has been built which combines the essential features of the versatile Flowing Afterglow/Langmuir Probe (FALP) and Selected Ion Flow Tube (SIFT) apparatuses. It has been used to determine the coefficients for the recombination reactions of NO+ and 02+ ions with electrons over the temperature range 200-600 K and for the attachment reactions of SF6, CCl4 and Cl2 with electrons at 300 K. The results of these studies are reported and are shown to resolve some of the differences which are apparent between the result of previous studies of some of these reactions. A reassessment, based on laboratory data, of the ion-ion recombination coefficients appropriate to the stratosphere is also presented and the new values are in good agreement with those derived from in-situ stratospheric observations by other workers. (Author)