216 



All incomplete analysis made by Dr. Max Buchner at Heidelberg 

 gave the following result; 



P^O^ 31.53 



CO' 7.31 



Fe=0» 2.83 



CaO 37.38 



MgO 2.17 



H'O to 110° C. ... 1.48 



H'O from 110—1250° C. 3.86 



insoluble residue . . 0.19 



86.75 



Qualitatively still a considerably large tjuantity of organic matter 

 and moreover thioiine and traces of chlorine was shown. The com- 

 position points to the fact, that 68.90''/„ tiicalcium-phosphale ought 

 to be present in the rock, which is less than witli most of the 

 phosphates from the Pacitic, whose typical representatives contain 

 38 to 407„ P'0\ 



Whereas 31.537„ P^'O* recjuire for the formation of the calcium- 

 tripliosphate 37.3770 t!aO, for the likewise occurring 7.317„ CO' 

 however no less than y.30°/„ CaO is required for CaCO^ there is a 

 residue of phosphoric acid extant that can only be bound to the 

 magnesium and the iron. Further it appeared that not the entire 

 CaCO' is mechanically mixed with the other substances. When it was 

 namely removed by means of acetic acid, the treatment with hydro- 

 chloric acid showed a very perceptible development of carbondioxyde, 

 so that we have decidedly to do with a carbonophosphate, which are 

 likewise the minerals Dahllite, Podolite and Francolite. The Nauruite, 

 moreover always contains fluorine, as likewise the phosphorite of Ajawi. 



P. Hambruch gives as formula for this mineral 

 3 (Ca'P'^0^) . CaCO' . CaF^ ') 



C. Elschner on the contrary 



/CaO 1 

 xCa^P'0"+ Ca(OH)' , in which x = 3 to 5") 

 ICaF' ! 



It is however clear, that witii the impurities, that are found in 

 all phosphates from the Pacitic, it is for the present decidedly 

 impossible to find a satisfactory formula. 



1) I. c. p. 680. 



-) Entstehung, Bildung und Lagening des Phosphats auf Nauru. Zeitschr. Gesellsch. 

 f. Erdkunde. Berlin 19112, p. 59. 



