186 



fallen.- dews and moisture necessary for vegetation. They 

 also defend the roots from the too sudden and scorching heat 

 of the sun in the day. They seem admirably suited for this 

 purpose, as their texture is such as to imbibe heat rather 

 slowly. Thus their being common is a happy providence, 

 and it is very reasonable to suppose that every pebble has 

 its destined use. 



A great deal more might be mentioned respecting their 

 utility in agriculture; but if what has been said is attended to,, 

 it will be found sufficient in this place. We may observe 

 that, when free from flaws and of a good colour, they will 

 bear cutting, engraving, and polishing, as well as the orien- 

 tal carnelians, which they partly resemble in their shining 

 fracture, and almost equal hardness. 



