274 FOSSIL FOOD 



living in the Caspian and the Black Sea alike testify to the 

 old line of water communication. One fine morning (date 

 unknown) the intermediate belt began to rise up between 

 them ; the water was all pushed off into the Caspian, 

 but the shells remained to tell the tale even unto this day. 

 Now, when a bit of the sea gets cut off in this way 

 from the main ocean, evaporation of its waters generally 

 takes place rather faster than the return supply of rain by 

 rivers and lesser tributaries. In other words, the inland 

 sea or salt lake begins slowly to dry up. This is now just 

 happening in the Caspian, which is in fact a big pool in 

 course of being slowly evaporated. By-and-by a point is 

 reached when the water can no longer hold in solution the 

 amount of salts of various sorts that it originally contained. 

 In the technical language of chemists and physicists it 

 begins to get supersaturated. Then the salts are thrown 

 down as a sediment at the bottom of the sea or lake, exactly 

 as crust formed on the bottom of a kettle. Gypsum is 

 the first material to be so thrown down, because it is less 

 soluble than common salt, and therefore sooner got rid of. 

 It forms a thick bottom layer in the bed of all evaporating 

 inland seas ; and as plaster of Paris it not only gives rise 

 finally to artistic monstrosities hawked about the streets 

 for the degradation of national taste, but also plays an im- 

 portant part in the manufacture of bonbons, the destruction 

 of the human digestion, and the ultimate ruin of the 

 dominant white European race. Only about a third of the 

 water in a salt lake need be evaporated before the gypsum 

 begins to be deposited in a solid layer over its whole bed ; 

 it is not till 93 per cent, of the water has gone, and only 

 , 7 per cent, is left, that common salt begins to be thrown 

 down. When that point of intensity is reached, the salt, 

 too, falls as a sediment to the bottom, and there overlies 

 the gypsum deposit. Hence all the world over, wherever we 



