70 



such far greater changes of cUmate formerly, or to some 

 independent agency, not yet discoverable, the circumstance is 

 not one that need much alarm us. Geologists tell us that 

 climates were very different ages back; that land and sea 

 have, perhaps more than once, changed places, causing by 

 their altered relative position a dis-arrangementof the meteoro- 

 logical conditions of whole latitudes. In this way countries 

 once arctic have become warmer; those that were once 

 tropical have become temperate. But these changes date 

 back to a period very remote, probably long before the appear- 

 ance of man on this earth. If the same changes are still 

 going on, they advance by such slow degrees as to be only 

 perceptible after the closest looking into all the phenomena 

 by which they are accompanied. 



Before our climate can again experience a complete reversal 

 of its present character, man may have run his course. He 

 need not fear, therefore, any interruption of those operations 

 in the field which he looks to as the main sources, not merely 

 of his daily sustenance, but of his wealth and prosperity. 

 He may continue to " plough in hope." If now and then he 

 has a bad season to contend with, he has a good one another 

 year to set against it ; or if the yield be deficient in one 

 country, it is met by more abundant supplies elsewhere. He 

 may trust the existing order of things. He has the promise 

 that, " while the earth remaineth," so long at least as it is 

 needed for man in his present state and circumstances, 

 " seed-time and harvest, and cold and heat, and summer and 

 winter, and day and night, shall not cease." 



