Hutton and Black. Engraving of James Hutton (left), British geologist, and James Black, British chemist. Hutton (1726-97) proposed that rocks took part in a continuous process of erosion into sediments and compaction of those sediments into rock (geological uniformitarianism). Black (1728-99) discovered 'fixed air' (carbon dioxide). He found that chemicals needed the same amount of energy to raise them through the same temperature rise (specific heat) but that extra energy (latent heat) was needed to change their physical state. The two scientists were part of an Edinburgh intellectual group which also included Adam Ferguson, James Hall and John Playfair.