 Those urea studies aimed to understand the processes occurring in living organisms and hinted that formic acid and urea should react at ambient conditions and form formylurea.After his return to the Collège de France in 1898 Matignon generalised his work to the thermodynamics of chemical systems and formulated an empirical law which Walther Nernst named the "Le Chatelier-Matignon rule".The law stated that for an equilibrated system of one gaseous
and one or more solid phases the ratio of the heat Q evolved at constant pressure and of the temperature T at which the gaseous pressure is equal one atmosphere is Q/T = 32.