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CHAPTER XVI 



LIFE AND LIVING CREATURES 



393. The World without Life. The World as a whole 

 may be compared to a great house. Geology describes its 

 materials, records the process of building, and keeps account 

 of the alterations which are always being carried out. Ocean- 

 ography has to do with the currents of water interchanged 

 between the tropical boilers fired by the central furnace of 

 the Sun and the polar refrigerators. It explains the arrange- 

 ments by which those rooms most exposed to the furnace are 

 cooled down by iced water, whilst those more remote have 

 their temperature raised by copious hot streams. Geology 

 records many past contests between the furnace and ice- 

 house in controlling the heating arrangements, and many 

 changes in the direction of the hot and cold water-pipes. 

 Meteorology discusses the still more complicated and vari- 

 able methods of ventilation in use in various rooms, depend- 

 ing as they do on the circulation of water and on the structure 

 of the buildings. Astronomy has something to say as to 

 the arrangements for lighting the great house, explaining 

 how each room is illuminated with a certain brilliancy for 

 a special time. Astronomy also supplies reasons for the 

 changes in the strength of furnace and refrigerators in the 

 past. Geography concerns itself with the plan of the house 

 so far as it is completed, showing the dominant style of 

 architecture and tracing the modifications adopted in the 

 several parts, and gives a general view of all the arrange- 

 ments. 



