THE 



LAWS OF CLIMATIC EVOLUTION. 



The objects of this paper are, to formulate the laws of 

 climatic evolution, and to show: 



1. That in consequence of these laws a hot spheroid, 

 holding water and air, or fluids of similar properties 

 within the sphere of its control, and revolving about 

 a source of solar energy, will be subjected to a series 

 of uniform climates, gradually decreasing in tempera- 

 ture, and terminating in an Ice Age; that this age will 

 be succeeded by a zonal distribution of climates, which, 

 within certain limits, gradually increase in temperature 

 and extent. 



2. That the difficulties met in the attempts to inter- 

 pret present, glacial and pre-glacial climates have been 

 due, in part, to a failure to give due weight to certain 

 of these laws, and to recognize the force of others. 



In attempting to trace the history of the earth back 

 into the infinite past, the first step brings us in con- 

 tact with the question: What was the cause of the Ice 

 Age? Before going farther it might be well to glance at 

 the theories which have been put forward to account for 

 this age, and to briefly consider the present position of 

 the scientific world as regards this first step in the prob- 

 lem. It is not necessary to review all the theories which 

 have been urged.* The principal ones only will be 

 mentioned in two classes. Class I embraces those 



*See The Climatic Controversy, S. V. Wood, Jr., Geol. Mag., 1876 and 

 1883. 

 Report British Assn., 1892, p. 708. 

 The Great Ice Age, Ed. 1894, Chap. IV, Dr. Prof. Geikie. 



