Prof. How on the Mineralogy of Nova Scotia. 37 



as large as a hen's egg, generally consisting of silky white fibrous 

 crystals ; these form with the dull blue matrix fine cabinet spe- 

 cimens. It is found also in common white gypsum, in selenite, 

 and in fibrous gypsum ; sometimes it has on its surface crystals 

 of calcite or Arragonite. At Newport it appears to be much less 

 abundant than at Brookville, and to occur in white gypsum only. 

 At both these places the mineral is imbedded in the matrix in 

 solitary nodules ; in one case I observed a nodule in a cavity 

 whose base was lined with crystals of selenite, among which it 

 was implanted. The nodules lately found, especially at New- 

 port, are not always visibly crystalline, and are generally, even 

 when silky fibrous, much harder in the interior than on the out- 

 side, the difference being about as 3 to 1. Careful analysis, 

 however, shows them to contain water, lime, boracic acid, and 

 soda, the latter being unmistakeably found in essential quantity 

 after removal of boracic and silicic acids by heating with fluor 

 and sulphuric acid : the crystalline form was seen under the mi- 

 croscope to be distinctly prismatic. Hence there is no doubt of 

 the mineral being natroborocalcite. 



As regards the composition of this mineral, I gave at a former 

 page a modification of the formula originally proposed by myself, 

 which, as at first given, was 



Na0 2B0 3 + 2CaO,3B0 3 + 15HO. 



This was proved by Dr. Kraut (Chemical News, February 22, 

 1867) to express most correctly the results of the best analyses 

 of the mineral by different chemists, but was objected to by Dr. 

 Lunge (loc. cit.) 9 who preferred the formula 



2(NaO 2 BO 3 ) + 5 (CaO, 2 BO 3 ) + 42 aq. 



The concordance of the analytical percentages with those calcu- 

 lated from these two expressions is as follows : — 





Lunge. 



A 



H 



ow. 



A 





Calc. 



Found. 



Calc. 



Found. 



Soda . . 



. 5-82 



5*58 



7-82 



721 



Lime 



. 1295 



12-69 



14-12 



14-20 



Magnesia . 



. . 



•50 







Water . . 



. 35-49 



36-85 



3404 



34-49 



Boracic acid 



. 45-74 



44-38 



44-02 



4410 



100-00 100-00 10000 100-00 



In my analysis all sulphuric acid was removed by washing with 

 cold water, a previous examination having given sulphuric acid 

 1*29, and magnesia 0'04 per cent. Dr. Lunge says the mineral 

 (he alludes probably to that from Peru) " is never found pure, 

 but always mechanically mixed with, and often perfectly pene- 



