On Isothermally Conjugate Nets of Space Curves.

this type. KHSO4 affords a notable example where three curves of this type meet in a triple point. For a liquid, As always decreases with increasing temperature on either a rising or a falling curve. On the rising transition curves there are 37 cases of normal variation of Av and 5 of abnormal variation; on the falling curves 8 normal and 8 abnormal cases. The relative compressibility, thermal expansion, and specific heat of neighboring phases is significant. It is natural to expect that the phase of smaller volume will have the smaller compressibility and thermal expansion, and that the phase stable at the higher temperature will have the higher specific heat. If we call this behavior 'normal,' then on rising curves we find 9 cases of normal and 11 of abnormal compressibility, and on falling curves 1 normal and 7 abnormal. The expansion shows 5 normal and 7 abnormal cases on rising curves and 2 normal and 4 abnormal on falling curves. Cp is normal in 5 cases and abnormal in 7 cases on rising curves, and normal in 6 cases and abnormal in 1 on falling curves. The fact of abnormal C. is of considerable significance from the point of view of the quaatum hypothesis. It means (if we may apply the same consideratios to Cp as to C,, which is usually done) that the specific heat curves of the two modifications cannot be of the same characte, but that somewhere between the transition point and absolute zero the one which is lower at the transition point must cross and lie above the other. In addition to the substances enumerated above, about 100 others have been examined without finding other forms.