232 UTILIZATION OP MINUTE LIFE. 



France, where it is called Corne de Dame, or Cliar 

 de Neptune. There are some splendid specimens of 

 this and its allied species in the British Museum. 

 Immense masses of its beautiful and wonderful 

 structure are employed to manufacture lime for 

 building and manure. The inhabitants of the 

 Polynesian and Australian islands burn it to pro- 

 duce the lime with which they chew their betel, and 

 scour the Holothuria which they collect for the 

 Chinese, etc., as we have already seen. The lime 

 thus produced is very much superior to any that can 

 be obtained from lime stone, however pure. When 

 employed as manure, it would be better to crush it 

 without burning it, as it would thus retain its animal 

 matter ; but some varieties are so hard, that the 

 crushing can only be effected with very powerful 

 machines. Madrepora and other closely- allied po- 

 lypes such as Porita, Astroea, Meandrina, Caryo- 

 phyllea (Fig. 30) contain from 90 to 95 per cent, 

 of carbonate of lime, with a little carbonate of 

 magnesia ; they also contain a very small quantity 

 of fluoride of calcium and phosphate of lime, which 

 latter, small as the quantity is, renders them still 

 more valuable for agricultural purposes. 



An analysis which I made of Madrepora muri- 

 cata, in 1859, gave me 5 per cent, of organic 

 matter, 0'4 of silica, 92 '2 7 of carbonate of lime, 

 0'69 of carbonate of magnesia, 0'65 of phosphate 



