PRODUCTS OF THE ERUPTIONS 253 



The discovery of argon in the gases of Pele is interesting. 



Hydrochloric acid is one of the gases often found in volcanic emis- 

 sions, and it is frequently inferred that it signifies that sea water has 

 gained admission, but I doubt this conclusion, as chlorine may be a 

 constituent of the earth's interior. At Vesuvius chlorine is given out 

 which becomes hydrochloric acid as it leaves the liquid lava. Chlorine 

 or hydrochloric gases have as yet not been recorded from Pele. 



Professor Lacroix * and his colleagues have also made observations on 

 the temperature of the expiring gases. f They speak of many fumaroles 

 on the slopes of mont Pele which emitted gases hot enough to melt lead, 

 though not copper wire. 



In a paper on the volcanic conditions in Martinique, Paris Academy 

 of Sciences, April 6, 1903, Professor Lacroix stated that the fiery clouds 

 produced in the eruption of mont Pele have been observed by him. 

 They consist of large volumes of hot gases and vapors carrying great 

 quantities of fragmentary products, and are the principal agents of de- 

 struction. Finally, it is encouraging to know that the able French 

 commission under the leadership of Professor M. A. Lacroix is contin- 

 uing its researches in the gases of Pele\ 



Other features of the volcano, some of which excited the greatest 

 current interest, were the lightning, the earthquakes, and the magnetic 

 storms. 



The terrifying lightning accompanying the eruption has been ex- 

 plained away as a secondary phenomenon, the product of the friction 

 resulting from the ascension of currents of hot steam. This explana- 

 tion may not be entirely true, but the subject is immaterial to our 

 story 



The earthquake tremors were local, not general (earth wide), in their 

 effects and most probably due to the vibrations caused by the explosive 

 work we have described. 



No satisfactory explanation has been offered concerning the cause 

 of the great magnetic storm which occurred simultaneously with the 

 eruption, but it is a singular coincident, suggestive of conditions pre- 



* The Geographical Journal, March, 1903. 



fThe intense temperature within the depths of the volcano can be but faintly conceived by 

 any observations of the materials which cooled upon reaching the atmosphere. This gave off 

 its heat slowly. The ash layers of Saint Pierre were still as hot as the hand could bear several 

 miles from the crater twenty-two days after the eruption only a few inches below the surface. 

 Six kilometers from the crater this material, eight days after the eruption, had a temperature 

 exceeding 100 degrees, according to Lacroix. Lacroix has also stated that the temperature of 

 the ash clouds of an eruption 6 miles from the crater was over 150 and under 250 degrees centi- 

 grade The temperature within the orifice was certainly sufficient to melt hypersthene-horn- 

 hlende-andesite, and in the depths it was probably sufficient to convert all or nearly all the 

 materials of the earth's interior into gases or a condition to become gases on release of pressure. 



