XXXIII. Thermal expansion of simple solids at low temperatures and Grüneisen's law

This is the authors' abstract. We don't add key points for this paper.

Experimental results on the thermal expansion of copper, aluminium, and iron are discussed in relation to Grüneisen's law. This law is shown to break down at temperatures below about 0·3θ, the thermal expansion becoming bigger than the values predicted by Grüneisen's law. A possible explanation is given.