| Answer | Crossword Clue |
|---|---|
| TREATISE | Euclid's "Elements," e.g. |
| SUBSTANCES | Elements, e.g. |
| TETRAD | The classical elements, e.g. |
| PLANEGEOMETRY | Euclid's "elements"? |
| PLANEGEOMETRY | Subject in Euclid's "Elements" |
| PLANEGEOMETRY | First subject in Euclid's "Elements" |
| ETHICS | Spinoza treatise modeled after Euclid's "Elements" |
