Van Schooten's Ruler Constructions - Conclusions

We can only speculate why van Schooten wanted to study constructions that did not use a compass.  It seems unlikely that he really mistrusted the accuracy or truth of a compass construction more than he mistrusted making marks on a ruler.  So, it may be that he simply relished the intellectual challenge of using different geometric tools.  Whatever his reasons, we can be grateful for these delightful nuggets of geometry from so long ago.