coolness produced elsewhere by rains, is here brought 

 about by fresh breezes, from the cooler regions. 



This is chiefly owing to the Andes, which running not 

 far from, and nearly parallel with the shore, and rising 

 immensely higher than any other mountains in America, 

 form on their sides a prodigious tract of lanrj, where, ac- 

 cording to their different heights, all kinds 'of climates 

 may be found, at all seasons of the year. These moun- 

 tains intercept great part of the eastern winds, which 

 generally blow on the continent of America, cool that 

 part of the air which comes over their tops, and keep it 

 cool by the snows, with which they are always covered. 

 Thus by spreading the influence of their frozen crests, 

 to the neighbouring coasts and seas, they cause the tem- 

 perature and equability which constantly prevail there, 

 But when they leave these mountains, they experience 

 in a short time an entire change of climate, and iu two 

 or three days pass from the temperate air of Peru, to 

 the sultiy atmosphere of the West Indies. 



The sparks which appear on striking fire with a flint 

 arid steel, are discovered by the microscope, to be so 

 many spherical balls of iron, detached by the blow from 

 the mass. They are then red hot. After they cool, 

 they are a sort of scoriae or dross. 



2. Fire is generated chiefly, either by collecting the 

 sun-beams by a glass, or by rubbing hard bodies against 

 each other. Either way the subtle matter is collected 

 from all sides, aud put into a rapid circular motion. 

 This continues together, as long as it is supplied with 

 inflammable substances. The particles of these being 

 divided by the fire, are scattered hither and thither, and 

 the fire goes out unless fresh fuel be brought : as it does 

 if air be wanting. For as that subtle matter is dissipa- 

 ting continually, it soon fails, unless recruited from the 

 air. If water or dust be thrown upon fire, it is like- 

 wise quickly extinguished. For these interrupt that in- 

 ternal motion, which is essential to it. 



