METEOROLOGY REVOLUTIONIZED BY THE WEATHER-MAP. 43 



tion, as they near the centre, is that of a spiral curve rather than a straight Hne. 

 The heated air at the centre of "Low" ascends in a like manner as boiling 

 water. The clouds brought by the winds generally precipitate before they reach 

 the centre, but not always. 



At times when a storm-centre is near us, yet not as near but what the clouds 

 are a little broken, if we will look heavenward we will see other lighter clouds 

 travelling in an opposite direction from those near the surface. These upper 

 currents are caused by the ascending currents at "Low," rushing outward to 

 fill the space on the upper part of the column of air in the regions of " High." 

 So we have " Low" moving in great horizontal circles along the earth's surface, 

 and in combination therewith the atmosphere moving in great perpendicular — 

 hoop-like — circles towards the track of these horizontal circles. 



The air from the bottom of " High " is being drawn from to supply " Low," 

 when it ascends and travels back to supply the top of the column "High," from 

 whence it was drawn. Thus the round of motion of the atmosphere, and thus 

 Nature's plan to keep the air we breath in healthy activity. Man in his small 

 way can never hope to equal this grand plan of Nature. 



If we were unacquainted with the peculiarities of Nature we would be apt 

 to think that the nearer we were to the equator the warmer it would always be. 

 It is generally warmer, that is, the general heat of the tropics is greater than 

 that of the temperate zones, and yet we know that it is oftentimes hotter from 

 45° to 50° N. Latitude than at or near the Equator. Before we had the per- 

 fected Weather-Map this phenomenon could not have been explained, but now 

 we not only can readily explain it but we can the better understand the infinite 

 wisdom in having it so. 



The Earth is .far more productive in consequence of the laws that govern the 

 concentration of the heat of the Sun, causing "Low" to frequently travel on 

 very high lines of latitude, whereby the necessary heat for the propagation of 

 plants, vegetables and fruits, essential for the existence of high animal life is ex- 

 tended so far from the Equator. 



There are portions of our earth's surface which never receive any benefits 

 from " Low," and these are desert places where there is no water present. There 

 is no heat in the earth, at least along its surface ; all the heat we have we derive 

 from the Sun. Desert places during the day are heated more readily and to a 

 greater degree than where there is an abundance of water present, but they 

 become very cold during the night. Between sunset and sunrise they lose the 

 greater portion of the heat they have received during the day. Wherever there 

 is water sufficient to generate clouds a more even temperature will be maintained 

 than where there is no water. " Low " will not stop over night where there is no 

 moisture. The clouds, including all moisture in the air, act as a canopy, or an 

 agent to retain the heat, so in order to convert a desert into a fruitful country, 

 one that will be visited by "Low," we must introduce water in some way, suffi- 

 cient at least to grow hardy trees and shrubs. 



The Map proves that the winds blow in general lines towards the "Low." 



