O. G. Harrington — Studies of Brazilian Favas. 359 



minerals as was done by Schaller, the differences be compared, 

 the following appear : 



Differences between goyazite and hamlinite. 



Goyazite Hamlinite 



Percent P,0 6 14-87 20-92 



" A1,0 3 50-66 32-30 



" H,0 16-67 12-00 



" F O'OO 1-93 



Infusible Fusibility 4 

 Not attacked by acids. Slowly soluble in acids. 



Schaller has also suggested* that hamlinite, plumbogummite, 

 gorceixite and florencite form a single group of phosphates 

 having the type formula [R /// (OH) 2 ] 6 E / '.[K / PO;j 2 .[R // (P0 4 ) J ] 

 thus making the formula of gorceixite [Al(OH) 2 ] 6 .Ba.[HPOJ 5 . 

 [Ba(POJ 2 ]. If the percentages given by this formula be com- 

 pared with those obtained by analysis the discrepancy seems to 

 the writer too great to favor the acceptance of this view. 

 Taking the mean of Hussak's two analyses of gorceixite as 

 reduced to 100 per cent by him and comparing the percentages 

 with those required by Schaller's formula the result is as 

 follows : 



Mean of 



Hussak's Schaller's 

 Analyses Formula 



P 2 5 24-00 27-76 



Al s O s 38-12 29-91 



BaO(Ca,Ce) 21-94 30-01 



HO 15-94 12-32 



100-00 100-00 



Unless later analyses should give different results, Hussak's 

 formula for gorceixite, therefore, seems preferable. On the 

 other hand it may be noted that Hussak's formula for hamlin- 

 ite, 2Sr0.3Al 2 3 .2P 2 5 .5H 2 0, gives too low a percentage of 

 water and also fails to take note of the content of fluorine in 

 that mineral. The percentage of water and fluorine obtained 

 by Penfield in his analysis of hamlinite was 13'93 per cent and 

 of water by Florence in his analysis 14-01 per cent. Yet the 

 percentage of water required by Hussak's formula is only 

 10*14 per cent. 



One of the favas of the lot obtained from Brazil differed 

 from those previously described in being nearly infusible and 

 turning black B. B. It also gave no characteristic flame color. 



*Loc. eit., p. 364. 



