Latest Francis A. Macdonald Stories
The Geological Society of America will recognize outstanding scientific achievements and distinguished service to the profession at its 2014 Annual Meeting & Exposition in Vancouver, British
Scientists find signs of 'snowball Earth' amidst early animal evolution.
- A pivoted catch designed to fall into a notch on a ratchet wheel so as to allow movement in only one direction (e.g. on a windlass or in a clock mechanism), or alternatively to move the wheel in one direction.