No. 4. J WP:ATnER AND ITS INFLUENCE. 43 



tioiis, which may well bear further study: "If the causes 

 are not tracea])le to atmospheric conditions, might they be 

 ascribed to the absence of the electro-magnetic conditions 

 which produce daylight?" "Would the use of artificial 

 means at night ha\'e any pei"ce})tible effect in stimulating the 

 organism of a patient whose critical condition requires more 

 of a vitalizer than rest?" " In cases where medicines have 

 been abandoned and certain treatment is being used for the 

 sole purpose of prolonging life, considering that when cer- 

 tain forms of electro-magnetic energy are exhibited deaths 

 are less frequent, would the introduction of strong electric 

 light to dispel darkness and its attendant morbidity 1k' an 

 auxiliary ? " 



Man is affected mentally and to some extent physically by 

 the tveatJier changes ; but the factor that really determines 

 whether a person can reside in any given locality, and con- 

 trols the growth and variety of vegetation, is climate. 



For example, an excessive rainfall for one or two seasons 

 may cause a luxuriant growth of vegetation on land usually 

 somewhat barren, or a succession of dry seasons will enable 

 one to work and cultivate land usually too wet for the 

 plough, while it is the average rainfall for five, ten or fifty 

 years that determines the agricultural value of the place. 

 Records show that because of a succession of wet seasons, 

 settlers have })ushed out into some parts of Kansas and 

 Nebraska that are usually semi-arid, and that with the one 

 or two dry seasons the crops have failed, and the land must 

 needs be abandoned, or else irrigation be resorted to. 



The climate of any section depends on the temperature, 

 moisture and wind. For temperature we must consider 

 monthly and annual means, the mean diurnal variability, the 

 monthly and annual extremes, the average dates of the latest 

 and earliest frosts, the mean intensity of the sunshine and 

 the extreme temperature of the soil at various depths. Com- 

 plete and valuable monthly and annual isothermal charts of 

 the world have been made, and from them Ave find the tem- 

 perature decreasing from the equator toward the poles, but 

 very irregularly and variably, especially in the northern 

 hemisphere. We find that the decrease in temperature 

 toward the poles is most rapid over large land areas and 



