- I continued to practice the method I had set for myself. In addition to following its rules for all my thoughts generally, I set aside certain hours specifically to apply the method to solving mathematical problems or even to questions from other sciences. By removing these questions from the less certain principles of those sciences, I made them almost as precise as mathematical problems. You can see evidence of this in the many examples included in this volume.
- Early Cretaceous (Wikipedia)
The Early Cretaceous (geochronological name) or the Lower Cretaceous (chronostratigraphic name) is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 145 Ma to 100.5 Ma.