168 RECENTLY DISCOVERED MINERALS. 



Atacamite — the green and the hlue. They differ slightly in their 

 chemical composition. The green variety he has named Botal- 

 lackite; and the blue, Tallingite. The following formulae will 

 indicate the relative compositions of Atacamite, Botallackite, and 

 Tallingite : — 



p / Atacamite— Cu^ CI + 3 Cu 0, H + Aq. 

 ijrreen | Botallackite— Cu", CI + 3 Cu 0, H + 3 Aq. 



Blue.— Tallingite— Cu^ CI + 4 Cu 0, H + 4 Aq. 



These minerals have evidently been formed by the alteration 

 of the cupreous compounds which occur in the lodes, through the 

 agency of the Chlorides of Sodium and Magnesium of the sea- 

 water in its passage through the natural joints of the rock. I 

 should suppose that the varieties are one and the same mineral, 

 in the different stages of its formation. 



This Atacamite group, as well as that which I had previously 

 mentioned, are undoubtedly minerals of comparatively recent 

 origin. They are definite chemical products, resulting from slow 

 decomposition of the more stable Copper Minerals, which occur 

 so abundantly in our lodes. 



Some years ago, Mr. Tailing found a Mineral which, from Mr. 

 Church's analysis, consists of a Hydrated Phosphate of Lime and 

 Alumina ; its formula being : 3 (Ca 0, P 0^) Al", 0^ + 3 H O. It 

 was found in the neighbourhood of Tavistock, associated with 

 Iron and Copper Pyrites and Childrenite. It is said to resemble 

 Wavellite in its physical characters. 



The mineral perhaps of greatest interest among those recently 

 discovered, is Churchite, named after the discoverer. Professor 

 Church. Its composition is a Hydrated Phosphate of Cerium. 

 It is found in a copper lode, on quartz and kiUas. The colour of 

 the mineral, according to Professor Church, is a pale smoky grey, 

 with a tinge of flesh red. It is an extremely rare mineral, and is, 

 I believe, the first Cerium compound that has ever been found of 

 British origin. 



Bayldonite is also a new mineral. It was found by Mr. 

 Tailing among a lot of minerals which formerly belonged to the 

 late Dr. Potts, and was supposed to be Arseniate of Copper. 

 Professor Church has, however, proved the presence of Lead and 



