Feb. 1900. New Mineral Occurrences — Farrington. 223 



obtained at each. The following are the percentages of loss obtained: 

 At no , 3.88%; at 240 , 1.94%; at 310 , 0.10%; at faint redness, 

 1.00%; total, 6.92%. Of the above amount, 5.99% was taken up 

 again by the mineral on exposure to ordinary air. This amount may, 

 therefore, be regarded as water of crystallization. On continuous 

 heating at faint redness, the mineral turned dark and showed a gain 

 in weight doubtless from oxidation of manganous compounds. It 

 was evident, therefore, that water could not be correctly determined 

 by loss upon ignition. 



A direct determination was made, therefore, upon a separate 

 portion by Penfield's method,* a blast lamp being used for the final 

 heating. This determination gave 8.20% of water. It could be dis- 

 tinctly seen on application of the higher heat of the blast lamp that 

 more water was given off at the high temperature, showing beyond 

 question that some of the water was present as water of constitution. 

 If the percentage of water taken upon exposure to air, 5.99%, be 

 regarded as water of crystallization, then the remainder, 2.21%, may 

 be considered to denote the percentage of combined water. This 

 agrees well likewise with Barwald's observations, he having found 

 1.97% of water given off above 300 . It is evident from the above 

 experiments also that determination of water as loss upon ignition 

 would certainly give too low a result. This may account for the low 

 percentage, 7.17%, obtained by Flink. 



The remainder of the analysis was performed by the methods 

 commonly employed for the analysis of silicates. A sodium carbon- 

 ate fusion was made, the bases separated from silica by solution with 

 hydrochloric acid, iron precipitated by ammonia, manganese by bro- 

 mine and calcium by ammonium oxalate. Results of the analysis 

 with ratios are as follows : 



, — „r at i _ — , 



SiO* 4489 748 748 1.64 



MnO 36.53 5i7l 



FeO 2.48 034! 699 1.53 



CaO 8.24 148] 



MgO tr. 



H,Ocryst 5-^9 336) 4$6 u 



H,Oconst 2.21 i2of 



100.34 

 Sp. Gr. (det. by Thoulet's solution) — 2. 965. 



The ratio of Si 2 : R O : H 2 is thus nearly 1.5 : 1.5 : 1. Consid- 

 ering the ratio of water of crystallization to water of constitution 

 s 3 : i, and of Mn : Ca = 4 : 1, the formula can be expressed as 



♦Amer. Jour. Sci., 3rd Ser., Vol. 48, p. 30. 



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