Spodunwne and its Alterations. 



33; 



In the determination of loss by ignition in Aglaite (XII), it 

 was found that this micaceous and porous mineral obstinately 

 retained some hygroscopic water above 100° C. 

 By long-continued heating, it lost — 

 At 110° C, 0.23 per cent (moisture). 



At red heat, 3.01 " " (water of combination and or- 

 ganic matter). 



The corresponding results, obtained on the fragment of origi- 

 nal Cymatolite received from Prof. Shepard, were as follows : 

 At 110° C, 0.37 per cent (moisture). 



At red heat, 3.28 " " (water of combination and or- 

 ganic matter). 



The sum of the latter figures closely approaches the result 

 reported by Prof. Burton (3.78 per cent.), which was obtained 

 (as he has informed me) from the mineral dried at 100° C. 



It may here be added, that the analytical figures given in my 

 preliminary notice of the composition of this mineral (Am. 

 Chem., I, 300, 1871),* and there temporarily assigned to Pihlite 

 in accordance with Dana's view (Syst. of Min., 455, 1869), are 

 too imperfect for further consideration. 



Theoretical Constitution. — From the average composition of 

 the mineral, given in column VII, the following elementary 

 constitution and ratios may be deduced, reckoning . 

 Mn, Mg, Ca=2 E 1 . 



Eatios 



Atomic. 



Percentages. 

 Si 27.39 





, ^- 



978 



12. 



Al 

 Fe 



12.31 

 1.02 



451 

 18 



- 469 



5.7 



Mn 



.19 



3^ 







Mg 



.38 



16 







Ca 



.44 



11 







Li 



.08 



11 



> 481 



5.9 



Na 



5.01 



218 







K 



4.88 



125 







n 



i\n [ basic 

 ( as aq. 



67 



163 



2. 







47.63 





2977 



36.5 



Quantivalent. 



3912 

 1407 



481 



163 



* Afterwards quoted in 2d App. to Dana's Min., 44, 1875, and Eoth's Allj 

 I, 382. 



u. Chem. Geol., 



