Occurrence at Hebron, Maine. 



219 



The following are the results of the analyses : 



Single piece. 



Weight of substance taken 



i. ir. 



0-6260 11291 



Loss by heating at 125°-130' 

 Loss by heating at 165°-170* 

 Loss by heating to red heat. 

 Loss by intense ignition 



1-49 

 0-04 



H 2 0. 



SiOo.. 



A1 2 3 



CaO . 



Cs 2 0. 



K 2 



Na 2 



Li 2 0_ 



1-53 



43-48 

 16-41 



0-21 

 36-?? 



0-4? 



1-72 



0-03 



[1-53] 



43-59 



16-39 



0-22 



35-36 



0-51 



203 



0-04 



III. 



IV. 



09491 



1-0205 



o-oo 





. .__ 



0-03 



1-50 



1-56 



.... 



0-02 



Two separate 

 pieces. 



V. 

 1-4826 



0-01 

 1-50 

 0-03 



1-50 



43-51 



16-30 



0-22 



36-10 



0-48 



1-68 



0-05 



1-58* 1-53* 



100-62 99-67 99-84 



The ratio calculated from No. Ill, and the calculated com- 

 position, giving the alkalies the same proportion as in the 

 analysis, but omitting lime and lithia as insignificant, is given 

 below : 



Hebron Pollucite. 

 Ratio from analysis III. 



Si0 2 



A1 2 3 ... 



CaO 



Cs 2 .... 



K 2 



Na a O-__. 



Li 2 



H 2 



•004^1 

 •128 | 

 •005 y 

 •027 | 

 •002 J 



•725 or 

 •160 



166 



•083 



4-53 



r 



052 



9-06 



2- 



2-08 



104 



Calculated for 

 H 2 B/ 4 Al 4 (Si0 3 )9 



Si0 2 43-55 



A1 2 3 16-45 



Cs 2 36-38 



K 2 0-48 



Na 2 1-69 



H 2 :_.. 1-45 



100-00 



The sharpness of the ratio and the agreement of the analysis 

 with the calculated composition are all that could be desired. 

 There can be* no doubt, then, that the composition of the 

 Hebron mineral is represented by the formula 9Si0 2 . 2A1 2 3 . 

 2K / 2 . H 2 or H 2 K' 4 Al 4 (Si0 3 ) 9 . The theoretical composition 

 for H 2 Cs 4 Al 4 (Si0 3 ) 9 , supposing no alkalies except Cs 2 to be 

 present, is, 



Si0 2 .- 40-72 



A1 2 3 1 5-39 



Cs 2 42-53 



H a O 1-36 



100-00 



A comparison of all the ratios given in this article, as shown 

 in the following table, makes it probable that the new formula 



* Not including, respectively, 0-03 and 001 per cent of water lost at 165°-170°. 



