Who was Joseph Black? #
Joseph Black (1728–1799) was the Scottish chemist who discovered carbon dioxide, transformed our understanding of heat, and helped lay the foundations of modern chemistry.
Friendly, curious, and famously modest, he taught at the University of Edinburgh and influenced generations of scientists—including his friend James Watt.
Joseph Black is one of Scotland’s quiet scientific giants—a chemist whose ideas changed the way we understand gases, heat, and the physical world around us.
Born in Bordeaux to a Scottish wine merchant and an Irish mother, Black came to Scotland to study medicine. He quickly became fascinated by what materials were made of. In the 1750s, he made a discovery that students still learn today: he identified carbon dioxide, which he called “fixed air.” At a time when people still believed in vague ideas like “phlogiston,” Black’s neat experiments proved that gases had weight, behaved differently, and could be identified one from another. This was revolutionary.
But he didn’t stop there. Black also introduced the concepts of latent heat and specific heat—showing that heat isn’t just about temperature, but about the energy absorbed or released during changes of state. These ideas became essential to physics, engineering, and later, the Industrial Revolution.
In Edinburgh, where he became Professor of Chemistry, Black was loved for his gentle teaching style. He kept meticulous lecture notes, preferred simple experiments over dramatic ones, and encouraged students to think rather than memorise. His straightforward, practical approach attracted huge audiences.
One of Black’s most important friendships was with James Watt, the engineering genius who improved the steam engine. Black encouraged Watt’s early experiments with steam, supported him financially, and provided the scientific grounding that helped Watt develop the separate condenser. This invention powered factories, mines, and eventually global industry.
Despite his enormous influence, Black remained humble. He shunned publicity, avoided arguments, and famously refused to publish until he was sure. However, his legacy is evident everywhere: in chemistry textbooks, physics classrooms, and the technologies that have shaped the modern world.
