INTRODUCTION TO THE STUDY 



OF SCIENCE 



CHAPTER I 



THE WEATHER 



I. How FORECASTS ARE MADE 



1. The atmosphere and life. The ocean of air at the bot- 

 tom of which we live is one of the most important parts of our 

 world. We do not usually recognize its importance unless we 

 are threatened with deprivation of it, or are subjected to air 

 that is bad and unsafe to breathe. Without air, however, life 

 is impossible. Air that is impure or robbed of its usual proper- 

 ties undermines health and causes life to become feeble and 

 miserable. 



No other part of our world exercises so great and uninter- 

 rupted influence upon all living things as does the air. The 

 air and its changes determine largely our manner of living and 

 working, the kind and amount of things we grow in the soil or 

 produce in factories, the sort of food we eat, and the kind of 

 shelter and clothing we enjoy. It may indeed be said that it 

 determines the kind of civilization the people of any given region 

 of the earth may have. 



2. Weather and climate. The changes in the conditions 

 of the atmosphere from one state to another, such as hot or 

 cold, wet or dry, clear or cloudy, calm or windy, are generally 

 summed up in the term weather. By this term we refer to 

 the conditions of the air at any particular time or for a given 



B 1 



