Complex sentence: Another innovation, of which he was very proud of, was an automatic self-recording mercury barometer that produced on a strip of paper its measurements; with this meteorological instrument he kept a continuous barometric record that covered a span of 30 years.
Split into simpler sentences: Another innovation, of which he was very proud of, was an automatic self-recording mercury barometer that produced on a strip of paper its measurements. From this meteorology instrument he kept a continuous barometric record that covered a span of 30 years.