﻿Prof. How on the Mineralogy of Nova Scotia. 271 



masses composed of white pearly scales : the largest was made 

 up almost exclusively of Howlite ; there was a little overlying 

 fibrous silky Ulexite, and a partial covering of the former by 

 some grey earthy carbonated gypsum, of which the quantity was 

 small -, the weight of the whole was about seven ounces avoir- 

 dupois : the second specimen was not much smaller ; the largest 

 previously known to me weighed only about two ounces. Along 

 with these fine and interesting specimens was one which at 

 once struck me as different from any I had seen ; this I did not 

 hesitate to beg, and I was kindly allowed to have it for exami- 

 nation. On looking over some nodules subsequently received 

 from the same place, I found two which resembled Mr. Brown's 

 so closely that I proceeded to analyze them. The results of 

 my investigation snowed that the 'unfamiliar nodules consisted 

 of a new mineral containing much sulphuric acid in addition 

 to the elements of silicoborocalcite. 



The nodule first examined (that from Mr. Brown's cabinet) 

 weighed about 470 grains; it had nearly the size and outline of 

 a walnut, and small colourless crystals of considerable lustre co- 

 vered the greater part of its exterior ; a small portion consisted 

 of earthy gypsum ; the rest of the mass was colourless and trans- 

 lucent. The fracture was nearly flat, and the new surfaces were 

 covered with glistening irregular facets. Under the microscope, 

 scrapings were seen to be transparent oblique-angled plates. 

 The hardness of the interior was about 3, that of the exterior 

 about 2. In the closed tube, fragments gave water and became 

 opaque ; before the blowpipe, decrepitated and fused readily to 

 a clear bead, giving from the first a bright green flame ; on con- 

 tinued blowing, frothing took place, the head became opaque, 

 and the flame was no longer coloured green. Hence the blow- 

 pipe reactions partake of those* which are so characteristic of 

 Howlite, as pointed out in my original description (Phil. Mag. 

 January 1868), and those of selenite. The following results 

 were obtained from the air-dry mineral ; the old nomenclature 

 and notation, still commonly used in mineralogy, are retained: — 



No. I. 

 Water ......... . . 18-80 



Lime 31*66 



Sulphuric acid .... 36*10 



Silicic acid 3*31 



Boracic acid (by difference) [10*13] 



100*00 



* It is curious that no reference is made to these well-marked reactions 

 in the description of this species in Dana's e Mineralogy,' fifth edition, 

 p. 598 ; in cases of possible doubt they promptly distinguish Howlite from 

 Ulexite. 



