xvi INTKODUCTION. 



and extensive contributions have been made to that on Monsoons, 

 Trade Winds, and Cj^clones. Lieutenant Jansen, of the Dutch 

 Navy, has helped me to enrich these with his fine thoughts. The 

 reader will, I am sure, feel, as I do, deeply indebted to him for so 

 much instructive matter, set forth in his very delightful and pleas- 

 ing manner. 

 National Observatory, Washington, April, 1856. 



