130 



A NATURALIST IN MEXICO. 



as described above. For three hundred years the sewers 

 of the city have attempted to discharge into lake Texcoco, 

 but the refuse matter is continually floating back again, 

 and so the filth of nearly five hundred years is accumu- 

 lated beneath the streets of the city. It is to assist this 

 drainage, also, that these works are being carried on. 



Two days were spent at Zumpango, and a good deal 

 of information gained concerning the geological formation 

 of the valley. On our return to Mexico we passed the lit- 

 tle town of Popotla, in which is the famous Arbol de la 

 Noche Triste, the ''Tree of the Sorrowful Night," under 

 which Cortez was said to have wept when driven from the 

 City of Mexico. This was an old cypress with blasted, 

 jagged limbs, and black trunk. It was surrounded by a 

 railing to keep curiosity hunters from carrying the tree 

 away. 



On the twenty-fifth of May we left the City of Mexico, 

 for the last time, for Veracruz, by the way of Tehuacan, 



where we wished to visit the 

 onyx quarries. As we sped 

 along the shore of lake Tex- 

 coco, the two mountains, Popo- 

 cateptl and Ixtaccihuatl, stood 

 out bold and clear as though 

 bidding us farewell. About 

 noon we arrived at Esperanza, 

 where we change from steam to 

 • mule traction for Tehuacan. 

 These tram-cars were very pe- 

 culiar, being divided into com- 

 -^z=: partments like an English rail- 

 TEEE OF THE SAD .NIGHT. ^' way Carriage. The line ran be- 

 tween two ranges of limestone hills, and was continually 

 descending. As we got deeper among the hills palmetto 



