ORDER IV. PRISMATIC GLAUBER-SALT. 81 



yet been ascertained, if perhaps the above analysis by KLAF- 

 ROTH does not belong to the present species. It seems to 

 differ from the hemi-prismatic Natron-salt, chiefly by its 

 containing a smaller quantity of water. It is, like the for- 

 mer, subject to decomposition, by which it loses its water, 

 and is reduced to a powder ; yet this effect does not take 

 place so easily and so quickly, as in the hemi-prismatic 

 species. If they are both contained in the carbonate of so- 

 da of commerce, the crystals of prismatic Natron-salt are 

 very often found to be quite fresh in the drusy cavities, 

 while those of the hemi-prismatic, are already entirely de. 

 composed. 



GENUS II. GLAUBER-SALT. 

 1. PRISMATIC GLAUBEE-SALT. 



Prismatic Glauber Salt. JAM. Syst. Vol. III. p. 31. Man. 

 p. 7. Glauber Salt. Sulphate of Soda. PHIL. p. 191. 

 Naturlich Glaubersalz. WERN. Hoffm. H. B. Th. 

 III. 1. S. 245. - Glaubersalz. HAUSM. III. S. 835. 

 Schwefelsaures Natron. LEONH. S. 617, Soude sul- 

 fate'e. HAUY. Tabl. comp. p. 19. Traite, 2de. Ed. T. 

 II. p. 189. 

 HAIDINGER. Edinb. Phil. Journ. No. XX. p. 305. 



Fundamental form. Scalene four-sided pyramid. 



p = ISP io'} ; uo 23/ ; 105 6K Inclina - 



tion = 14 41' in the plane of the long diagonal. 

 Vol. I. Fig. 41. R. G. 



a : b : c : d = 3-816 : 7'005 : 3-188 : 1. 

 c If T> /A jP f " 1 f 93 12' 1 



Simple forms. P Gc(Z); - | z | = | 81 o 10 . |; 



