 He also found that both types of ice can be kept at normal atmospheric pressure in a stable condition so long as the temperature is kept at that of liquid air, which slows the change in conformation back to ice Ih.In later experiments by Bridgman in 1912, it was shown that the difference in volume between ice II and ice III was in the range of .This difference hadn't been discovered by Tammann due to the small change and was why he had been unable to determine an equilibrium curve between the two.