Hart. — On Terrestrial Magnetism. 131 



atmosphere and to abuonnally excite the magnetism of its 

 oxygen. This abnormally - magnetized oxygen, in the usual 

 circulation of the air occasioned by the heat of the tropics 

 flowing over towards the poles and becoming condensed, dis- 

 charges its abnormal electro-magnetism in light. 



The fact of the earth's atmosphere being thus rendered 

 self-luminous suggests the probability that the luminosity of 

 the sun is due to the friction of the planets rolling round him 

 acting upon suitable materials. 



I am persuaded that, when opportunities of observation 

 have been afforded, and the facts are ascertained, it will be 

 found that the magnetic poles of the earth are not fixed in 

 position, but movable. They are nearest to the axial poles 

 of the earth at the times of the equinoxes, and farthest from 

 them at the times of the solstices. 



The electro-magnetism of the earth's atmosphere on trees, 

 plants, and animals has a vitalising influence. Upon trees 

 and plants it operates by aiding the circulation of the sap. In 

 man it influences the animal spirits. This can be proved by 

 observation. The southerly breeze in this City of Wellington 

 brings its oxygen into a normal electro-magnetic state. The 

 breeze coming from the north in its passage over trees and 

 plants has parted with some of its electro-magnetism, and is 

 not so refreshing. Still more noticeable is the efl'ect on a day 

 of cloud and fine rain — for then trees and plants, rendered by 

 the moisture which clings to them more than usually good con- 

 ductors of electricity, are drawing from the atmosphere its 

 electro-magnetism and almost visibly growing, while man and 

 other animals are dull, and, as far as they are liable to be 

 affected by weather, dispirited. 



In high latitudes the strength of men is not only due to 

 the warm clothing and oleaginous food the consumption of 

 which helps to keep up the animal heat, together with the 

 action of the oxygen of the atmosphere upon the blood, but is 

 also to be attributed to the electro-magnetism of that oxygen, 

 which, while the air at a temperature many degrees below 

 freezing-point is being inhaled, acts upon the nervous system, 

 quickens the circulation of the blood, and vitalises the system. 



