342 Review of Alger^s Phillips^ Mineralogy, 



Later analysts do not discover the cerium supposed to be detected 

 in it by Dr. Thomson. 



Polyadelphiteoi Thomson, (p. 135.) This mineral, from Sus- 

 sex Co., N. J., is nothing but a yellowish granular garnet, as is 

 readily seen at the locality. Compare the analysis, p. 135, with 

 the composition of garnet, on pages 23, 24 and 25 of our author. 



MarmoZzVe of Nuttall, (p. 153.) This mineral, from Hoboken, 

 N. J., is still continued as a species, although long since determined 

 by Shepard to be identical in composition with serpentine. The 

 analyses of Vanuxem* and Lychnellf lead to the same conclusion. 



Boltonite, (p. 154.) This mineral has been united by Mr. Al- 

 ger with Picrosmine, and we think without sufficient reason, as 

 the Boltonite, according to Thomson's analysis, is anhydrous, 

 while Picrosmine contains nearly seven and a half per cent, of 

 water, and its resemblance in other respects is not very close. 



97-33, Magnus. 



Talc, Chlorite, Soapstone, (pp. 155, 150.) Talc and chlorite 

 are united in one species by Mr. Alger, and steatite separated from 

 talc. The investigations of Lychnell have shown that steatite 

 (soapstone in the arts, speckstein of the Germans) is identical with 

 talc in composition, and that both are anhydrous. The soap- 

 stone of Cornwall, [saponite,) confounded by Mr. A. with steatite, 

 is a hydrous species, quite peculiar in its butter-like consistence 

 when moist, and its white earthy appearance on drying. Chlo- 

 rite contains 8 to 12 per cent, of water, and is wholly distinct 

 from talc. Von Kobell separates chlorite on chemical grounds 

 into the two species, chlorite and ripidolite-X Nacrite, which is 

 united, in the work before us, with talc, has the unctuous feel of 

 this mineral, but is aluminous instead of magnesian. 



Danhurite oi Shepard, (p. 172,) is a doubtful species, as stated 

 in Vol. xLiv, p. 384, of this Journal. 



* J. Acad. Sci. Philadelphia, iii. t K. Vet. Ac. Hand. 1826. 



t Erdmann's Jour. xvi. 



