The rounded form ofy is found with the value of G in R EC E I, which is probably the dative of rex.

EF is the change of volume corresponding to a change of pressure BE when no heat is allowed to escape and the path is the adiabatic BF, EC is the change of volume for the same change of pressure BE when the path is the isothermal BC. These changes of volume are directly as the compressibilities, or inversely as the elasticities.

C, Cordylus, composed of flattened ectoderm ec covering a large-celled endodermal axis en.