52 MEXICO, CENTRAL AMERICA, WEST INDIES. 



The soutlierlv or south-easterly storms, which have received from the missionaries 

 the curious name of Cordonazo de San Francisco, or " Scourge of St. Francis," 

 rarely penetrate far into the interior, although a town of Michoacan, near the 

 verge of the central Mexican uplands, has with good reason been named Ario, 

 that is, the " Stormy " in the Tarascan language. 



On the west side, the prevailing currents are the so-called papagai/os, or north- 

 easterly trades, and the south-western monsoons, that is, the trades of the southern 

 hemisphere attracted to the north of the equator, and deflected from their original 

 course. 



Owino- to the contrasts in the relief of the land, the differences of temperature, 

 and the irregularity of the winds, the rainfall is distributed very unequally through- 

 out Mexico, thouo-h it is chiefly regulated according to the seasons. Towards the 

 middle of May, when the sun stands near the zenith of the northern hemisphere, 

 the rains begin to fall. The clouds, following the track of the sun along the 

 ecliptic, discharge frequent torrential downpours, at least on the slopes facing 

 seawards. Usually, the approaching storm is indicated by a great black cloud 

 risino- from the sea " like a huge torso with half -mutilated limbs." It is locally 

 called the giganton, or " Giant," who will soon swallow up all the heavens. In 

 the afternoon the clouds are rent asunder, and lit up by flashes of lightning 

 accompanied with thunder, in which the ancient Aztecs recognised the voice of: 

 the god Tepeyolotl, or " Heart of the Mountain," rumbling in long echoes over 

 the hills. The sudden downpours are followed by rain lasting usually till 

 nio-htfall. Then it clears up, and by dawn the winds have already dried the 

 ground. 



On the Mexican plateau the tropical rains, brought by the north-easterly 

 winds, fall regularly only during the four months from June to September, and 

 the showers generally last less than an hour. The rains are also interrupted, 

 especially in July and August, by numerous fine days, and even by weeks of dry 

 weather, " St. Anne's Spring," as it is then called. They cease altogether in Octo- 

 ber, when winter begins, which however presents some of the features of a Euro- 

 pean summer ; hence its name of est'io, " summer," or tiempo de secas, " dry season." 

 It is the lack of moisture in the ground, rather than the low temperature, 

 that strips the trees of their foliage, and thus imparts a wintry aspect to the land- 

 scape. But the lofty ranges also assume their snowy mantle at an altitude of 

 13,000, and even 12,500 feet. In exceptional years, the Ahualco Pass (11,5*20 

 feet) has been covered with snow all the way from Popocatepetl to Ixtaccihuatl, 

 and a few flakes have even at times fallen so low as Morelia (6,400 feet). 



Numerous irregularities, however, are everywhere caused by the differences 

 in the relief and aspect of the land. Thus two contiguous districts will some- 

 times have a totally different distribution of moisture. In certain regions, notably 

 the temperate zone of Jalapa and Orizaba, from 1,500 to 8,000 feet high, the 

 vapours brought by the northern winds are condensed in fogs which lie on the 

 surface and precipitate a fine but persistent mist. This is the so-called chipichipi, 

 which is awaited M-ith impatience by the natives, for whom it is the essential 



