INTRODUCTION. 



T^HIS catalogue of the " non-metallic minerals " in the collec- 

 ■*- tion of the Royal Institution of Cornwall forms the first of a 

 series which it is intended to publish from time to time. 



The old primary classification of the mineral series into two 

 "divisions," non-metallic and metaUic, has been retained — not 

 because it is thought to be the most philosophical arrangement 

 possible-— little can be said of it in this respect — but because it has 

 many practical advantages in a mining locality. 



The non-metallic division is again subdivided into the following 

 '* classes." 



1. (Carbon and Boron. 



2. Sulphur and Selenium. 



3. Haloids and Salts. 



4. Earths. 



5. Silicates and Aluminates. 



These being the classes adopted for the collection at the Royal 

 School of Mines in London. 



The several classes are again subdivided into groups, each group 

 being characterised by the presence of some common and dis- 

 tinctive ingredient in considerable proportions ; or, in the case 

 of the SiHcates, by some mineral possessing marked physical 

 characters. 



This I St division of the mineral collection occupies the whole of 

 the first five cases and one half of the sixth, the numbering being 

 from left to right throughout. The following specimens are par- 

 ticularly worthy of notice : — 



Case I. — The various forms of native Bitumen, from Mines near 

 Redruth, and from Castleton in Derbyshire (Nos. 18-22) ; the 

 Hatchetiite formerly found in cavities of ironstone at Merthyr 



