226 CLASS III.— ORDER 11. 



bright hue, or, by its incessant attrition with harder 

 bodies, is reduced to powder. 



Coral is found at different depths in the heart of 

 the waters, but, notwithstanding the density of the me- 

 dium in which it exists, all aspects are not suitable to 

 it. On the coasts of France it covers those rocks that 

 face the south; it is rarely found on those having an 

 eastern or western aspect, and never on those having a 

 northern one. It is never met with at less than three 

 metres below the surface, nor ever at a greater depth 

 than three hundred metres. 



In the straits of Messina it prefers an eastern as- 

 pect ; on the south it is seldom found, and still less on 

 the rocks of the north or west. They there fish it 

 from a depth of one hundred to two hundred metres. 

 In those straits, which Homer and Virgil have im- 

 mortalised, the solar rays strike more perpendicularly 

 than on the coast of France, their heat penetrates to 

 a greater distance, and the Coral is found even deeper 

 than three hundred metres ; but then its quality no 

 longer compensates for the risks and numerous diffi- 

 culties which attend the procuring it. 



On the north coast of Africa it is not sought be- 

 yond thirty or forty metres in depth, and at a distance 

 of three or four leagues from shore ; they abandon it 

 when it reaches two hundred and fifty or three hun- 

 dred metres. 



The influence of light appears to operate power- 

 fully on the growth of Coral. A foot of this ani- 

 mal production, to acquire a determinate height, re- 

 quires eight years in water of the depth of from 

 three to ten fathoms ; ten years, if the water is from 



