WORD SPIRTAL

Starting from 1, fill in the grid clockwise with four-letter words. The last letter of each word becomes the first letter of the next to reveal a famous physicist. 1. Lock openers 2. Painful 3. Catch sight of 4. Egg part 5. Eager 6. Christmas 7. Plant part 8. Swift, quick 9. Snare 10. Mountain lion 11. Female relative 12. Rain heavily 13. Castle surround 14. A native of Thailand 15. Concept 16. Atmosphere