173 



Supposing the fluoric acid to be united with lime, and to consti- 

 tute fluor spar, the constitution of the mineral is thus expressed : 



11A13S4- \ f > 3S + liCal3S + 2Mag3S + 2Aq 



( Mn ) 

 The mineral is designated in honor of Dr. Holmes, Prof, of Chem- 

 istry in the McGill College of Montreal. 



2. Compact Feldspar, from JBytown, Lower Canada. Sp. gr. 

 2.8617. 



According to Dr. Thomson, it is identical with Amphodelite, 

 which he considers a variety of Scapolite. The formula of Scapo- 

 liteis2AlS4-CalS. 



3. Deweylite ?* Sp. gr. 2.0964. 



Silica, . . . . 50.70 



Magnesia, 

 Water, 

 Alumina, 

 Protox. iron. 



23.65 



20.60 



3.55 



1.70 



* The locality of this mineral is not known. 



