IN PHYSICS. 229 



11. If a vessel of water containing a floating body be 

 placed under the receiver of an air-pump, and the air 

 gradually exhausted, what will be the effect on the floating 

 body? 



12. How will it change the height of the column of 

 mercury in a barometer to incline the tube ? 



13. In the image of a written page seen in a mirror, why 

 does the writing seem to slope to the left ? 



14. Why does a coin placed in a tumbler look i*r&jr 

 when the glass is full of water than when it is empty ? 



15. Two bodies of different bulks weigh the same in 

 water; which will weigh the more in mercury, the larger or 

 the smaller ? 



1 6. flow does the wind drift sand, snow, etc. ? 



1 7. Why does oil " still troubled waters " ? 







1 8. Why does crouching down at the highest points in a 

 swing, and standing up at the lowest point, increase the 

 velocity ? 



19. What difference would it make in the guinea-and- 

 feather experiment to force into the tube additional air, 

 instead of exhausting it, as ordinarily done ? 



