251 



we added successively in concentrations of 1 mol. percentage, the 

 following chemically pure preparations: 



Observed and reduced 

 Melting points: 



14415 M.V. = 1382° 

 14506 M.V. = 1414° 

 14304 M.V. = 1397° 

 14585 M.V. = 1420° 

 14530 M.V. = 1416° 



14357 M.V. = 1402° 

 14593 M.V. = 1421° 



1. Jadeite: NaAlSi^O^, synthetical. 



2. Leucite: KAlSi^Og, synthetical, anhydrous. 



3. Lithiumod'ide: Li^O. 



4. Alumina: Al^O^. 



5. Silica : SiO, (quartz). 

 And in concentrations of 2 mol. perc: 



6. Pseudowollastonite: G^SY(^3, synthetical. 



7. Sillimannite: Al^SiOr^, synthetical. 

 Keeping in mind, that the pure substance melts at 1417° C 



(G. Th.), we can deduce from these experiments, that : 



a. An excess of Li^O lowers the meltingpoint of the compound 

 LiAlSioO^, while the influence of an excess of SiO^ is somewhat 

 uncertain, but seems to produce a slight increase. 



b. That a lowering of the meltingpoint is also produced by an 

 excess of synthetical jadeite, leucite and pseudowollastonite, which can 

 be considered as the principal admixtures of the natural kunzites 

 and spodumenes. 



c. That on the contrary, an /?icrmóY of the meltingpoint is produced 

 by an excess of alumina and of alumo silicates, like e. g. pure 

 sillimannite. 



In how far these facts, which of course will be studied moi-e in 

 detail, when the ternary system: Li J) — Al^O^—SiO^ is investigated 

 completely, can be used for the explanation of the phenomena, 

 observed in the case of the natural spodumenes, will be shown in the 

 next paper. 



Groningen, May 1914. Laboratory of Inorganic Chemistry 



of the University. 



Cliemistry. — "Studies in the Field of Silicate-Chemistry. III. On 

 the Lithiumaluminiumsilicates, lohose composition corresponds 

 to that of the Minerals Eucryptite and Spodumene" . By 

 Prof. Dr. F. M. Jaeger and Dr. Ant. Simek. (Continued). 

 (Communicated by Prof. P. van Romburgh.^ 



(Communicated in the meeting of May 30, 1914). 



§ 12. For the purpose of comparison of the properties of the 

 described artificial product with the mineral itself, we have inves- 

 tigated a number of natural spodumene-s^eaies in an analogous way. 



