SCIENTIFIC SUMMARY. 



XIII. — Recently discovered Minerals. — By Eichard Pearce, Jun., 



Swansea. 



^URINGr the last three years, the science of Mineralogy has 

 been greatly enriched by the discovery of a number of very 

 interesting Minerals ; and by far the greater number of these 

 have been found in Cornwall. 



Some time ago, Professor Maskelyne, of the British Museum, 

 discovered, associated with the Arseniates of Copper of Cornwall, 

 two new minerals ; and they have been named Langite and War- 

 ringtonite. Both these minerals are basic sulphates of copper, 

 and are allied in composition to Brochantite. 



Not long after the discovery of the latter minerals. Professor 

 Maskelyne noticed another mineral on the Langite, which he 

 named Lyellite. M. Pisani, a French chemist, was, however, the 

 first to make known its chemical composition and characters ; and 

 he has called it Devilline, in honour of Deville, the distinguished 

 French chemist. Its composition is, according to M. Pisani, the 

 following : Cu 0, Ca 0, Fe 0, 3 S 0^ + 3 Aq.,— a sulphate of Cop- 

 per, Iron, and Lime. According to Professor Church, the Oxide 

 of Iron is an accidental impurity, and does not enter into the 

 chemical composition of this mineral. 



Langite occurs in beautiful blue crystals, with the Arseniates 

 and other Copper minerals. Mr. Tailing, of Lostwithiel, has told 

 me that it is not confined to one locality in Cornwall. 



Last year, Mr. Tailing found the mineral Atacamite at St. 

 Just. It is an Oxychloride of Copper ; and, until recently, it was 

 thought to occur only in Chili, and in the craters of volcanoes. 

 Professor Church, of the Royal Agricultural College, Cirencester, 

 was, I believe, the first to examine chemically the mineral which" 

 came from Cornwall. He found that there were two varieties of 



