During his studies he wrote a doctorate thesis on the treatment of kidney stones with the salt magnesium carbonate.

[3] Like most 18th-century experimentalists, Black's conceptualisation of chemistry was based on five principles of matter: Water, Salt, Earth, Fire and Metal.

Black's research was guided by questions relating to how the principles combined with each other in various different forms and mixtures.

[5] Throughout his career he used a variety of diagrams and formulas to teach his University of Edinburgh students how to manipulate affinity through different kinds of experimentation.

He found that limestone (calcium carbonate) could be heated or treated with acids to yield a gas he called "fixed air."

Black related an experiment conducted by Daniel Gabriel Fahrenheit on behalf of Dutch physician Herman Boerhaave.

Additionally, Black observed that the application of heat to boiling water does not result in a rise in temperature of a water/steam mixture, but rather an increase in the amount of steam.

Black provided significant financing and other support for Watt's early research in steam power.

Black's discovery of the latent heat of water would have been interesting to Watt,[14] informing his attempts to improve the efficiency of the steam engine invented by Thomas Newcomen and develop the science of thermodynamics.

In addition to regularly introducing cutting-edge topics and meticulously selecting visually impressive experiments, Black employed a wide array of successful teaching tools that made chemistry accessible to his students (many of whom were as young as 14 years old).

[16][17] His students came from across the United Kingdom, its colonies and Europe, and hundreds of them preserved his lectures in their notebooks and disseminated his ideas after they left university.

His voice in lecturing was low, but fine; and his articulation so distinct, that he was perfectly well heard by an audience consisting of several hundreds.

He died peacefully at his home 12 Nicolson Street[24] in south Edinburgh in 1799 at the age of 71 and is buried in Greyfriars Kirkyard.

In 2011, scientific equipment believed to belong to Black was discovered during an archaeological dig at the University of Edinburgh.