230 HANDBOOK OF NATURE STUDY 



. .> 

 It has also been found that agriculture has a great effect 



upon the climate of a country. At the time of Caesar, 

 Holland, Belgium, and Germany were covered with inter- 

 minable swamps and forests and had a very cold and cloudy 

 climate. To-day these countries have been transformed into 

 sunny gardens and fields, where all the grains and fruits of 

 the north temperate zone flourish. Old chroniclers and old 

 settlers tell us that in this country the winters were more 

 severe formerly than they are now and that snow and rain 

 were more abundant. Although the different reports of such 

 changes must be accepted with caution, they are no doubt true 

 in general. Can you see why agriculture should make a coun- 

 try drier and warmer ? Is such a change beneficial in every 

 respect ? How can some of its attendant evils be avoided ? 



America furnishes us a very interesting chapter in the 

 history of civilization and in the history of mankind. About 

 two hundred and fifty years ago small bands of white people 

 from England, Ireland, Scotland, Holland, Germany, and 

 Sweden settled on our eastern coast and hewed small clear- 

 ings into the dark, boundless forests. They had brought 

 with them their domesticated animals and cultivated plants. 

 Many weeds, now common, and many insect pests, and also 

 such pests as domestic mice and rats, were accidentally 

 introduced. To-day the white man and the animals and 

 plants which, purposely or accidentally, he brought over 

 with him are in possession of the continent; a continent 

 which is among the most productive, but which nevertheless 

 had never developed a high, general civilization. 



REFERENCE BOOKS 



The teacher and mature pupils will find the following books very 

 interesting and very instructive : 



Tarr. Physical Geography. The Macmillan Company. 1897. $1.40. 



Shaler. Nature and Man in America. Scribner, New York. 1891 . $1.50. 



Gnyot. The Earth and Man. Scribner, New York. $1.75. 



Shaler. Story of our Continent. 



