"''••' Scientific IntelUgence: 417 



ciated with phosphoric acid, thorina, oxide of cerium, oxide' of 

 tin, &c., in the monazite of Miask. ai-J >g oiu 



2. CJiemical Composition of DatoUte and Botryolite. — It' re- 

 sults from the analyses of Carl Rammelsberg (Poggend. No. 5, 

 1839, p. 169), that datolite and botryolite are distinguished 

 from each other by their proportion of water of composition, — 

 botryolite containing double the quantity of water of datolite. 



3. Andalusite and Chiastolite varieties of the same Species.— 

 From the experiments of R. Bunsen of Cassel, in Poggendorff's 

 Annalen, No. 5, for 1839, p. 186, it appears that the chief in- 

 gredients of andalusite and chiastolite are as follows : — Anda- 

 lusite, silica, 40.66; alumina, 59.34 = 100.00. Chiastolite, 

 silica, 40.03; alumina, 59.97 = 100.00. Hence it appears 

 that, on chemical principles, andalusite and chiastolite are 

 identical, or only varieties of the same species. .^.^-j 



4. Chemical Composition of Mikrolin. — The mikrolin is pro- 

 posed by Breithaupt as a distinct species, and separated from 

 felspar. The separation rests chiefly on small differences in 

 the angles of the crj^stals. As the determination of the true 

 nature of this mineral was also of importance in a geological 

 point of view, M. J. v. Ewreinoff, captain in the Russian En- 

 gineers, analysed it under the eye of G. Rose, and obtained 

 the following result, which shews that this mineral agrees with 

 felspar in chemical composition, with exception of the small 

 quantity of lime, which has taken the place of a portion of the 

 potash :— Silica, 65.761; alumina, 18.308; lime, 1.200; potash, 

 14.060; soda, magnesia, and oxide of iron, a trace, = 99.329. 

 —Poggendorff's Annal No. 5, p. 196, 1839. 



5. Chemical Composition of Monazite. — This is one of the 

 many new mineral species added to the system by Breithaupt 

 (in 1829). As it cannot well be compared with any known 

 species, and appears in some degree isolated in the system, he 

 named it Monazite. Its peculiar chemical constitution also 

 shews the name to be well chosen. Kersten of Frcyberg (i)«V/e 

 Poggcndorff, No. 6, 1839, p. 385,) found its composition to be 

 as follows : — oxide of cerium, 26.00 ; oxide of lantan, 23.40 ; 

 thorina, 17.95 ; oxide of tin, 2.10 ; oxide of manganese, 

 1.86 ; lime, 1.68 ; titanic acid and potash, a trace ; phospho- 

 ric acid, 28.50 = 101.49. 



