34 Prof. How on the Mineralogy of Nova Scotia. 



Water . . 

 Lime . 



Sulphuric acid 

 Magnesia . 

 Silica . . . 

 Boracic acid 



I. 



, -*- -, II. 



Mean. 



11-51 11-60 11-55 11-62 



28-90 28-90 28-04 



1-03 1-03 0-80 

 .... trace trace 

 15-12 15-27 15-19 15-44 

 43-33 44-10 



100-00 10000 



The softest mineral, found in nodules imbedded in gypsum, 

 is so unlike the preceding in hardness that at first I thought it 

 might be effloresced glauber-salt which I had formerly met with 

 in a similar matrix (see papers above referred to). It is like soft 

 chalk or coherent flour, so that it is very difficult to separate 

 pieces of the rock holding it without losing a great deal under 

 the blows of the hammer. Its flame and blowpipe-reactions, 

 except that it does not decrepitate, are those of the harder mi- 

 neral ; it colours turmeric and gelatinizes with equal ease. Ana- 

 lysis of a specimen like flour, obtained by myself among debris 

 at the quarry, gave (air-dried) :— IIr 



Water ...... 12-20 



Lime 28*85 



Sulphuric acid .... 1 '86 



Magnesia trace 



Silica . 14-64 



Boracic acid .... 42*45 



100-00 



These results agree so closely with the foregoing from different 

 specimens in a distinct matrix, that there can be no doubt they 

 all relate to a different mineral whose composition is constant in 

 its varying physical conditions. The percentages correspond 

 remarkably well with those calculated from the formula to which 

 they lead. The results placed below as found are those of III., 

 the analysis just given, after deduction of the quantity of gypsum 

 equal to the sulphuric acid obtained, which is much greater in 

 this than in the preceding analyses, whose numbers are so ob- 

 viously similar that deduction in all is quite superfluous : — 

 Calculated. 



, A v Found. 



5HO = 45 11-43 11-84 



4CaO = 112 28*44 28-69 



2Si0 2 = 61-62 15-65 15-25 



5B0 3 = 175-20 44*48 44*22 



393-82 100-00 100-00 



