During his chemical revolution, Lavoisier created a new instrument for precisely measuring out gases. He called this instrument the gazomètre. He had two different versions; the one he used in demonstrations to the Académie and to the public, which was a large expensive version meant to make people believe that it had a large precision, and the smaller, more lab practical, version with a similar precision. This more practical version was cheaper to construct, allowing more chemists to use Lavoisier's instrument.