from Cumberland, R. I. 109 



the sample, powdered for analysis, was kept for two hours at a 

 temperature of 110° C. 



In executing the following analyses the water was deter- 

 mined by direct weight, the pulverized mineral being heated to 

 faint redness in a glass tube and the water collected in a 

 weighed chloride of calcium tube. The ferrous oxide was de- 

 termined by the ammonium fluoride method given beyond, the 

 soda by heating with calcium carbonate and ammonium chlo- 

 ride, and the other constituents by fusion with sodium carbon- 

 ate in the usual manner. To corroborate the determination of 

 ferrous oxide a calculation was made from the difference be- 

 tween the weight of the water found and the actual loss sus- 

 tained by the sample, this difference presumably representing 

 the amount of oxygen required to convert the ferrous oxide 

 into ferric. The average of four water determinations is 3*56 

 per cent, while the average loss by heat was 1*03 per cent. 

 The difference, 2*53 per cent, represents oxygen, and corre- 

 sponds to 22 '11 per cent of ferrous oxide, corroborating the 

 results obtained by the other method, which are the figures 

 used in the following analyses. 



1. 2. 



Si0 2 - 52-13 51-03 



Fe 2 3 15-93 17-88 



FeO 21-25 21-19 



MgO. 0-22 0-09 



Na 2 6-26 6-41 



H 2 3-95 3-64 



Total 99-74 99-94 



There seem to be good grounds for considering the water 

 basic, and an essential constituent, for it requires nearly, if not 

 quite, a red heat to drive it all out, and the taking up of oxy- 

 gen at the same time shows a molecular rearrangement. Under 

 the supposition that the water is basic the empyrical formula 

 suggested is Fe 3 Na 2 H 4 Fe,Si 9 27 , or 3FeO, Na 2 0, 2H 2 0, Fe 2 0„ 

 9Si0 2 , which requires the percentages given in the first 

 column of the table below, the second column giving the ratio 

 calculated from the same figures by dividing the percentages of 

 the oxides found by their molecular weights, and the third col- 

 umn the ratio calculated from the average of the two analyses 

 given above. 



1. 1. 3. 



Si0 2 53-25 -887 -860 



Fe 2 3 ... 15-78 -098 '105 



FeO 21-31 -296 '299* 



Na 2 6-11 ' -098 -102 



H 2 3-55 -197 *210 



* With the MgO. 



