SM Intelligence and Miscellaneous Articles. 



Oxygen. 



Silica 45-97 '23-880 . . 5 



Alumina 3208 14-982 . . 3 



Magnesia 10-32 ~] 



Protoxide of iron 3-83 > 4-956 . . 1 



Protoxide of manganese 041 J 



Water 5-49 4-879 . . 1 



Lime, oxides of lead, ^ 



copper, cobalt, and > 0-45 



titanium J 



98-55 



Formula ^ > So + 3 A S + aq. 



It might be therefore considered as dichroite containing water, or 

 as Fahlunite with half the quantity of water. 



APHRODITE. 

 Berlin has undertaken the examination of this Swedish mineral, 

 which has been considered as meerschaum. That from Taberg in 

 Wermeland and from Salm, has exactly the same composition as 

 serpentine, and is nothing else than serpentine with the form of 

 meerschaimi. But the so-called meerschaum of Langbanshyttan, 

 which is similar to the foregoing in other respects, has a different 

 composition, and on account of its similarity to meerschaum is named 

 aphrodite (from d<f>pos, Schaum, froth, foam) . It is composed of 



Oxygen. 



Silica 51-55.. 51-58 26-79.. 8 



Protoxide of manganese 1-62.. 1-49 



Protoxide of iron 059 . . 055 > 013 > 13-65 . . 4 



Magnesia 33-72 . . 34-07 



Alumina 020.. 0-13 



Water 12-32.. 11-34 10-07 .. 3 



which gives the formula of 4 M So -f 3 Aq. We possess therefore 

 three natural compounds of bisilicate of magnesia combined with 

 different quantities of water. 



Pikrosmine 2 M So + aq. 



Pikrophylle 3 M Sg + 2 aq. 



Aphrodite 4 M So + 3 aq. 



CORAL REEFS. 

 Mr. Darwin's long-expected work on this interesting subject has 

 just appeared, it is entitled, " The Structure and Distribution of Coral 

 Reefs : being the first part of the Geology of the Voyage of the Bea- 

 gle, under the command of Captain Fitzroy, R.N., during the years 

 1832 to 1836. London, 1842." (pp.xii. and 214.) It is illustrated 

 by three plates, and some engravings in wood : the former of these, 

 1st, showing the resemblance in form between barrier coral reefs 

 surrounding mountainous islands, and atolls or lagoon-islands ; 2nd, 

 map and section of the Great Chagos Bank, and maps of the Men- 

 chioofF Atoll, Mahlos Mahdoo Atoll, New Caledonia, and Maldiva Ar- 

 chipelago ; 3rd, showing the distribution of the different kinds of coral 

 reefs, together with the ])osition of the active volcanos in the map. 



0-34 ~| 



0-13 J> 



13-18J 



