PROBLEMS OF TERRESTRIAL MAGNETISM 755 



The production of static electric charges by the rapid ejection of 

 particles of steam or vapor is well known. It may thus be possible that 

 the violent and tremendous ejection of vaporous particles from within 

 the volcanic cone produced such a high electrification of the regions 

 above the volcano as to have sufficiently altered the potential of the 

 semi-permanent electrification of the upper regions to have immedi- 

 ately produced an inflow or outflow from outside space of electric 

 charges so as to make the resultant effect comparable to that asso- 

 ciated with a magnetic storm coming from without. 



It will be recalled that the products ejected by the eruption were 

 described to be principally of a vaporous or gaseous character and 

 finely powdered ash. All reports dwell especially upon the electric 

 flashes over the mountain during the eruptions. 



If it is possible, therefore, to disturb the entire earth's magnetism 

 by an explosion on the earth, our conceptions as to the manner of the 

 connection of magnetic disturbances and solar eruptions have had 

 some light shed upon them. 



It is, furthermore, of interest to add that the solution of the actual 

 cause of the rapid and complete destruction of all life in the ill-fated 

 town of St. Pierre may find some assistance in the study of the mag- 

 netic disturbance. Thus it will be recalled that in many instances it 

 was found that the death-dealing, scorching blast passed through 

 the clothing without injuring it, burning the flesh beneath, however, 

 to a crisp. This might be explained, if, for example, there were in 

 the mountain crystals of copper sulphate. The rapid heating of this, 

 accompanied by violent ejection, would be accompanied by enormous 

 electric charges and the production of vaporous sulphur trioxide. The 

 latter, violently ejected, would pass through the clothing, doing 

 comparatively little injury to it, but as soon as the vapor entered the 

 pores of the body, it would combine with the finely divided particles 

 of water in the skin and form sulphuric acid, which in turn burned 

 the flesh and quickly brought death to the afflicted. Certain other 

 substances would have a similar action. 



Had we time, we might bring forth a most interesting case of the 

 relationship between physiographic features of a land area and irregu- 

 larities in the magnetic distribution. Such an instance is shown by the 

 recently completed magnetic survey of Louisiana. 



Permit me to call your attention to the great and promising field 

 of inquiry relating to the role played by the terrestrial magnetic lines 

 of force in deflecting or dissipating such solar radiations as affect the 

 magnetic needle and which are prevented, possibly with benevolent 

 purposes for our welfare, from reaching the lower depths of the atmo- 

 sphere. With respect to such radiations, these magnetic antennae of 

 the earth may perform the same function as does our atmosphere 

 with respect to swarming meteors. 



