ARBORICULTURE 



a monthly magazine. 



Published in the Interest of the 

 International Society of Arboriculture. 



Subscriptiou. $2.00 per annum. 



J. P. Brown, Editor, Connersville, Indiana. 



Volume 1 1. 



Indianapolis, September, 190:5. 



Number 



Mexico's Volcanos. 



We illustrate in this number two of 

 Mexico's historic mountains. Popocatepetl 

 which has long been extinct as a volcano, 

 and Colima now in active operation. 



The surface formation throughout Mexico 

 shows a distinctive volcanic origin and the 

 remains of craters and volcanic peaks are 

 very numerous. Many of the higher mesas 

 are covered with rough, igneous rocks, while 

 over a large area of the rolling lands are 

 porous strata indicating the flow of volcanic 

 mud which has hardened to a greater or 

 less degree, yet not always into solid stone. 

 In plowing some of the fields a shallow 

 layer of soil has been formed by action of 

 the elements while immediately beneath 

 lies this volcanic deposit. 



Among the most noted volcanoes are 

 Popocatepetl, 17,784 feet elevation, Ixtacci- 

 huatl, 15,705, and Malintzi, 12,462, all long 

 since extinct, while Colima the only active 

 valcano is 12,728 feet high. 



Large portions of the earth surface have 

 during the world's history, been convulsed 

 with earthquake upheavals and volcanic 

 eruptions. It has been a great period since 

 the volcanoes of Mexico were pouring forth 

 fire and lava. The country is now and has 



been for a great while tranquil. 



Colima, in the southwestern portion of 

 the Republic is intermittently active. Its 

 crater seems not to be totally closed, but a 

 small quantity of vaper escapes continually. 

 Ashes or fine sand are deposited upon the 

 slope of the mountain when a sudden ex- 

 plosion occurs. 



This is probably in the character of a 

 steam safety valve which permits the 

 escape of gases from within the earth which 

 would otherwise force an outlet with earth- 

 quake violence. 



Parties who have ascended to the summit 

 of Popocatepetl have preserved photo- 

 graphs which show the great extent of ice 

 and snow at this elevation, although but 

 nineteen degrees removes from the equator. 



A volcano in action is one of the grand- 

 est sights which human eyes ever beheld. 

 One watches the little stream of smoke or 

 vapor, scarcely distinguishing it from the 

 floating clouds which hang above the top of 

 the high mountain, the wind from the east 

 carrying the vapor in a slight horrizontal 

 stream. When suddenly an explosion takes 

 place, the column pours out with such force 

 and volume that it rises to the height of 

 several miles, apparently, in whirling, curl- 

 ing masses as is seen on our engraving of 

 Colima, driven upwards by a force greater 

 by far than any power of which man has any 

 knowledge. 



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