MIDWINTER 133 



lessen the loss of heat from the warmer water 

 below. The coat of ice, once formed, remains on 

 the surface by its buoyancy, the warmer water 

 below is kept fluid, and the life of plants and ani- 

 mals is able to continue. That floating sheet of ice 

 is a diagram of the moving equilibrium of the 

 world. 



