2 Introduction to the S'udy of Science 



period, such as an bour, a day, a week, or even for a season. 

 The total series of weather changes and conditions is generally 

 described by the term climate. This term is sometimes con- 

 sidered to be equivalent to the average weather of a region. 

 Such a use of the term is inadequate, because climate must in- 

 clude several factors neglected in any account of the average 

 weather. Some of the factors which climate necessarily in- 

 cludes are these : the extremes, the irregular variations, and 

 the mean of such unusual temperatures ; the humidity, cloudi- 

 ness, rainfall, and the amount of rainfall accompanying cyclonic 

 and local storms ; the distribution, duration, and frequency 

 of any weather conditions. If you consider the average 

 weather of your own locality, you will at once realize that you 

 get from it a very inadequate idea of the climate, that is, the 

 total series of weather conditions. 



3. Kinds of climate. Climates are roughly distinguished 

 from one another by such descriptive terms as mild or rigorous, 

 hot or cold, wet or dry ; or as the climate of Florida, California, 

 New England, the Bermuda Islands, Italy, Siberia, and so on. 

 We are familiar also with the classification of climates by zones, 

 as the tropical, the two temperate, and the two polar zones. 

 There are other classifications based on the conditions affect- 

 ing plant life, animal life, or general geographic considerations. 

 Perhaps the following classification is as useful as any: the 

 oceanic climate, sea level continental climate, and mountain 

 climate, with such subdivisions as coast climate, desert climate, 

 and monsoon climate. This classification gives due considera- 

 tion to the conditions which actually control climate, namely, 

 sun, water, land, and altitude. It gives moreover a peculiar 

 definiteness to the several climate zones. 



4. Prediction of weather changes. Common consideration 

 of the weather does not stop with the mere statement of the 

 present conditions of the atmosphere, but it leads to the effort 

 to forecast the kind of weather changes to be expected. Men 

 have learned that while the unfavorable features of the weather, 



