422 KANSAS CITY REVIEW OF SCIENCE. 



tells us that the Moon has no atmosphere, but it would seem before we decide 

 the point that we must first determine what atmosphere is. It is not necessary that 

 the Moon have an atmosphere like the earth in order to be recognized as having 

 an atmosphere. 



But for the presence of water the Earth would have no more atmosphere 

 than the Moon, so atmosphere in the sense as generally understood must be the 

 product of moisture or something resulting therefrom. These remarks about the 

 moon may seem a little of a digression, yet they naturally follow when we come to 

 speak of atmosphere. 



In this connection some may wonder why the planets and Moon are not 

 considered as factors in our meteorological economy — for the simple reason that 

 they have not the least bearing in the case and therefore are not factors. Noth- 

 ing but concentration of heat effects the meteorology of the earth, and only the 

 Sun has power in this direction. There is no heat from the stars, therefore no 

 effect. " How about attraction ? " some may ask. The reply to this is, no one 

 who would study the weather-map for a season and see for themselves how storms 

 travel would be apt to put any dependence upon the accidental relative position 

 of the stars or other heavenly bodies than the Sun. The storms come from the 

 development and concentration of the clouds and movement of the atmosphere, 

 and neither the stars, planets, nor even the Moon, have any power over this de- 

 partment. The earth is beholden to the Sun and only to the Sun for its meteor- 

 ological phenomena ; it alone is the major factor — the great positive, active 

 force, while the earth in relation to it is the minor-negative, passive power. 



The next great factor, or better, factors, for they are really distinctive and 

 peculiar in their results, is the combinations of motions of the earth in space ; its 

 daily motion on its axis — its yearly motion about the Sun, and the gradual oscil- 

 ating motion of its axis which exposes different parts of the Earth's polar axis 

 more directly to the influence of the Sun. 



The daily motion of the Earth on its axis exposing every twenty- four hours 

 the surface of the Earth to the heat of the Sun is the factor of all the daily changes; 

 the yearly motion of the Earth about the Sun is combination with the parallelism 

 of the Earth's axis is the factor of the yearly or season changes. The common no- 

 tion is that the yearly motion of the Earth about the Sun in the only and sole 

 cause of the changes of the seasons, yet but for what science terms the "parallel- 

 ism of the Earth's axis " in connection there with these changes would not take 

 place, for the Sun shining perpendicular to the Equator would produce a same- 

 ness and no variety — all our months would be alike and the habitable portions of 

 the globe would be much reduced, at least for such organisms as at present 

 flourish upon it. 



It is said that we are sometimes nearer to the Sun than at others, but the 

 distance is comparatively so infinitesimal that it amounts to little or nothing, and 

 practically would not be noticed.' The third motion, the gradual change in the 

 angle of the incUnation of the Earth's axis, the oscillation of the poles, whereby 

 the polar axis describes a circle in the heavens of some 25,000 years, is the factor 



