358 0. C. Farrington — Studies of Brazilian Favas. 



composition suggests that of the mineral hamlinite with 

 barium replacing strontium, but the ratios do not seem to 

 warrant identifying the two minerals. The ratios give the 

 formula: 2Ba0.4Al,0 3 .3P 5 5 .llH 2 0, which written in the 

 form of a normal phosphate becomes 



(BaOH) (A10H) 4 (P0 4 ) 3 .3H,0. 



Calculating the JSTa 2 and CaO of the analysis as BaO, reckon- 

 ing F as H.,0, omitting Fe 2 3 and calculating to 100, the per- 

 centages found by the analysis and calculated on this formula 

 compare as follows : 



Calc. Found 



BaO 22-90 23-06 



A1 3 3 30-51 30-24 



P 2 6 31-81 32-00. 



HO 14-78 14-70 



100-00 100-00 



A mineral phosphate of this formula has not before been 

 observed and it may be that a new mineral species should here 

 be recognized, but owing to the lack of crystal form and the 

 possibility that the substance may be a mixture, it would seem 

 to the writer advisable to obtain confirmatory evidence before 

 assigning to it a specific character. The substance of this fava 

 was tough, apparently homogeneous and cryptocrystalline. It 

 fused at 3 with swelling to a white enamel and gave off acid 

 water in a closed tube. Of its optical properties nothing can 

 be stated since, unfortunately, all the substance of the fava was 

 used for the chemical analysis. 



So far as analyses indicated, no favas in the lot corresponded 

 in composition to goyazite. It will be remembered that 

 Schaller* urged that Damour's goyazite was in reality hamlin- 

 ite. One of Schaller's reasons for this conclusion was a doubt 

 expressed by Hartley as to the accuracy of the method 

 employed by Damour for separating A1„0 3 from P 2 O a in an 

 analysis of plumbogummite made by Damour in 1840. 

 Damour's analysis of goyazite was made in 1884, and even if 

 the same method of analysis was employed in the two cases, it 

 does not seem to the writer certain that it was especially 

 defective. While the occurrence of a hydrous calcium alumi- 

 num phosphate of the composition described by Damour evi- 

 dently needs confirmation, the present evidence hardly seems 

 to the writer sufficient for regarding goyazite and hamlinite 

 the same. If instead of comparing the similarities of the two 

 * This Journal (4), xxxii, 359, 1911. 



