So Nature's 



will recede to the level maintained before the 

 shot was put in. On the contrary, if we 

 should pour an equal bulk of cork or pith balls 

 into the jar the water would not be displaced, 

 because the balls are lighter than the water 

 and would lie on top of it; if, however, the 

 water is removed from the jar, the cork will 

 immediately go to the bottom of the jar, be- 

 cause the cork is heavier than the air which 

 has taken the place of the water. We wish to 

 impress upon the mind of the reader the fact, 

 that all substances of a fluidic nature, whether 

 in the fluid or gaseous state, have weight, and 

 obey the laws of gravitation, and the heavier 

 portions will always seek the lower levels, and 

 in doing this will displace the lighter por- 

 tions, causing them to rise. There is no ten- 

 dency in any substance to rise of itself, but 

 the lighter substance rises because it is forced 

 to do so by the heavier, which displaces it. 

 This law lies at the bottom of all of the phe- 

 nomena of air currents. 



If we are at certain points on the seashore 

 in the summer time we may notice that about 

 9 o'clock in the morning a breeze will spring 

 up from the ocean and blow toward the land; 

 this will increase in intensity until about 2 

 o'clock in the afternoon, when it has reached 

 its maximum velocity, and from this time it 

 gradually diminishes, until in the evening 

 there will be a season of calm, the same as 



