164 PHYSIOGRAPHY. 



the sulphur is precipitated. According to KLAPBOTH, 

 it consists of 



Tin 34-00. 



Copper 36-00. 



Iron 2-00. 



Sulphur 25-00. 



It is found near St Agnes in Cornwall, with pyramidal 

 Copper-pyrites, dodecahedral Garnet-blende, &c. 



TOERELITE. 

 Torrelite. RENWICK. Ann. of Phil. 



No description. 



The analysis by Professor RENWICK gives 

 Silica 32-60. 



Peroxide of Cerium 12-32. 

 Protoxide of Iron 2 1 -00. 

 Alumina 3-68. 



Lime 24-08. 



Water 3-50. 



It occurs in Sussex county, New Jersey. 



TRONA. 



SALT. 



Trona. HAIDINGER, 



For Synonymes, vide Vol. II. p. 27- Tr 

 Edinb. Journ. of Science. Vol. II. p. 325. 



Hemi-prismatic. Combinations observed resem- 

 bling Fig. 75., without r. Inclination of M on 

 T = 103 J5', of n on n, adj. = 132 30', nearly. 



Cleavage highly perfect, parallel to M 9 traces par- 

 allel to T and n. Fracture uneven. Surface, 

 T often striated parallel to its edges of combi- 

 nation with M. 



Lustre vitreous. Colour white, sometimes yellow- 



