﻿Prof. How on the Mineralogy of Nova Scotia. 273 



Calculated. 



20 HO . . 



= 180-00 



18-40 



Found. 

 18-00 



HCaO . . 



= 308-00 



31-47 



31-14 



8 SO 3 . 



= 320-00 



32-69 



31-51 



SiO 2 . 



= 30-81 



3-14 



4-98 



4B0 3 . 



, =140-16 



14-30 



[14-37] 



978-97 100-00 100-00 



The agreement here, though not quite so close as in the pre- 

 ceding case, is sufficient to show that the formula chosen most 

 probably represents the composition of the substance analyzed ; 

 and the resemblance of the results to those from No. 1 proves 

 that we have to do with closely related minerals. In fact I view 

 the second as theoretically derived from the first by the inter- 

 change of one atom of boracic acid and a little silica for one of 

 sulphuric acid, and as being a variety of the species for which I 

 propose the name Winkworthite. 



This new species is intermediate between selenite and silico- 

 borocaleite (Howlite), thus : — • 



I. =«. II. sa/3. 



fllCaO llCaO (ap n 



sin* s,n2 4ta(J 



Winkwor-J 9 gQ 3 8 gQ 3 Silicoboro-j2SiO* 



thite= '] 3B0 3 4BQ 3 calcite= ] 5BO» 



L20HO 20HO l - nU 



and it may originate from the reaction of their elements during 

 or after deposition. The nodular form, which is the charac- 

 teristic of Howlite as contradistinguished from the crystalline 

 habitude of selenite, seems to show that the former was the ori- 

 ginal deposit, in which case Winkworthite would be a pro- 

 duct of its alteration by selenite. Nodules of selenite occasion- 

 ally occur in the gypsum-beds here resembling exactly the amor- 

 phous forms of the borates, of which they are probably the 

 pseudomorphs. I have examined several specimens of Howlite 

 for sulphuric acid : in some cases mere traces were present, both 

 in the hard crystalline and the soft opaque conditions of the mi- 

 neral ; while in other specimens, respectively similar, the quan- 

 tity has been decided and sometimes considerable, even after 

 every precaution had been taken to exclude selenite, which, as 

 mentioned in my original description (Phil. Mag. Jan. 1868), is 

 often present in bands traversing the borate. 



In describing the distinct acicular prisms as a new form of 

 natroborocalcite (Ulexite, Dana), I named the locality Newport 

 (Phil. Mag. April 1870) ; but it should have been called Newport 



