38G PHYSIOGRAPHY. CLASS n. 



ably to the delicacy of the individuals in this com- 

 position. 



OBSERVATIONS. 



1. According to the same principles which require us' to 

 consider Red Hematite or fibrous Red Iron-Ore, as a varie- 

 ty of rhombohedral Iron-ore, we must also unite within 

 one and the same species, the Wood-tin of Cornish miners, 

 with the rest of the varieties of pyramidal Tin-ore. The 

 distinction of the two species, Tin-stone and Cornish Tin- 

 Ore in the Wernerian system, rests only npon the state of 

 mechanical composition, and must therefore be abandoned, 

 as has been already done by several mineralogists. 



2. The following ingredients were found by KLAFROTII 

 in a simple variety, by DESCOTILS in a compound one : 



Oxide of Tin 99-00 95-00. 



Oxide of Iron 0-25 5-00. 



Silica 0-75 0-00. 



In its greatest purity it contains nothing but oxide of tin, 

 Sn, composed of 78-67 metal, and 21-33 oxygen. Alone it 

 does not melt before the blowpipe ; but is reducible when in 

 contact with charcoal. It is insoluble in acids. 



3. This ore occurs disseminated in rocks, particularly in 

 granite, also in beds and veins, and in those large irregu- 

 lar masses called Stockwcrke. It is frequently accom- 

 panied by prismatic Scheelium-ore and pyramidal Schee- 

 lium-baryte, rhombohedral Molybdena-glance, also by 

 rhombohedral Quartz and other species. It occurs in 

 pebbles, and is extracted in this shape from stream-works. 

 The varieties called Wood-tin have been hitherto found 

 only in these repositories. 



4. There are but few countries in which the present spe- 

 cies is met with in any notable quantities. These are 

 Saxony, Bohemia, Cornwall in Europe, and the peninsula 

 of Malacca and the island of Banca in Asia. Small quan- 

 tities occur in Galicia in Spain, in the department of Haute 

 Vienne in France, and in the mountain chains called the 



