The measurements of gas phase H2SO4 in the stratosphere have been continued. It has been realized that the measurements may include other sulfur-containing species such as HSO3 and HSO5. The technique has been improved through the use of a mass spectrometer with a larger mass range and better measurements of the parameters involved in the derivation of the H2SO4 concentration. The results from the first two flights of this new instrument are reported, and the older data have been