Determine the melting temperature of a substance f...

Reassessing phase lines and slopes

The red vertical-ish lines seem to represent the G-axis arrow and axes at 89 and near 90. So, the slopes of 70-80 are closer to vertical lines, not phase lines like I originally thought. The only real diagonal line of interest appears to be moderate-slope, possibly representing one phase. There might be another faint diagonal line, but it’s hard to pinpoint due to its subtlety. For two-phase diagrams, I'd expect a line with a cusp or intersection — this scribble may show a piecewise line, though I only see one apparent line.

Thought for 7m 43s