€h. VII. SOUTH AMERICA. S:; 



tending themselves under the plains, and traversing 

 them in several directions. This being admitted, it 

 will appear, that in whatever country volcanoes, or 

 depositaries of these substances, are very common, the 

 plains will be more diversified with these ramifica 

 tions ; for we are notto ini i2:ine thatit is onlv within 

 the bosoms of mountains that substances of this na- 

 ture exist, and that they are not disseminated through 

 all the parts of the adjacent region. Thus the coun- 

 try now under consideration, abounding in these igne- 

 O'lis substances more than any other, must by the conti- 

 nual inflammation which necessarily follows their na- 

 tYiral preparation for it, be m^re exposed to earth- 

 quakes. 



Besides the suggestions of natural reason, that a 

 country containing many volcanoes must also be every 

 where veined v. ith ramifications of correspondent sub- 

 stances, it is confirmed by experiment in Peru ; where 

 we find almost universally mines of nitre, sulphur, 

 vitriol, salt, bitumen, and other inflammatory sub- 

 stances, which sufficiently confirm the truth of these 

 iiiferences. 



The soil both of Quito and Valles, particularly 

 the latter, is hollow and spongy, so as to be fuller of 

 cavities or pores, than is usually seen in that of other 

 countries ; and consequently abounds with subterra- 

 neous waters. Besides w^hich, as I shall presently 

 shew more at large, the waters, from the ice continu- 

 ally melting on the mountains, being filtrated through 

 these pores during their descent, penetrate deep into 

 the cavities of the earth; and during their subterra- 

 neous course, moisten, and turn into a kind of paste, 

 those sulphureous and nitrous substances; and though 

 they are not here in such prodigious quantities as in 

 volcanoes, yet they are sulricient, from their uifiatn- 

 matory quality, to rarefy the air contained in them, 

 wdiich easily incorporating itself with that ronfuied in 

 the innumerable pores, cavities, or veins of the ear(h, 



comprcrsL • 



