18 On a New Mineral from M'lvor. 



white crust. This latter fume can be driven away by the 

 reducing flame, turning greenish blue ; the yellow crust disap- 

 pears with an azure blue shine. 



" According to these tests the mineral ought to contain sul- 

 phur, antimony, and lead. To make, however, more certain 

 of it, the powdered mineral was mixed with soda, and again 

 brought on charcoal before the reducing flame. The results 

 were fine lead-like globules, with a yellow fume close to 

 them, and a thin bluish-white one further off. As the me- 

 tallic globules appeared rather brittle, they were fused toge- 

 ther, and (to take up the lead) brought into contact with a 

 small portion of boracic acid: the reducing flame produced 

 herewith red pearls of metallic copper, clearly distinguishable 

 on the edge of the slag. 



" The phosphorsalt bead received from the mineral a fine 

 emerald-green colour, identifying the presence of copper. 



" In the open test-tube the heated mineral smelts very easily, 

 causing a white, not fusible, sublimate not far up the tube, 

 and emitting strong fumes of sulphurous acid, which redden 

 blue litmus paper put in at the unheated end of the tube. 

 In the half closed tube the mineral smelts, and sublimates 

 rings of greyish white and white colour ; no smell of sulphu- 

 rous acid perceptible. This latter trial in the tube leaves 

 now some doubt of the presence of antimony, or at least of 

 such a portion of it as to bear an essential part in the chemi- 

 cal composition of the ore as a sulphide. To come to a cer- 

 tain result, however, the ore was brought together with a 

 small piece of iron-wire in a cylindrical hole on the charcoal, 

 and a mixture of borax and soda, in proportion of 1-2, was added 

 as a covering, and the whole mass covered for a while with a 

 good reducing flame. The regulus of lead with antimony 

 (the sulphur having formed a slag with the iron) was taken 

 out of the slag, and, on another piece of charcoal, brought 

 into contact with boracic acid. The reducing flame produced 

 in this way again small reguli of copper, surrounded only by 

 .a very thin white fume, — doubtless oxide of antimony. 



" By way of these tests, and according to Plattner's experi^ 



ments, the ore is cuproplumbit, Pb 2 + Cu., with a small 

 quantity of antimony, or it is a sort of Bournonite; the 

 components of which are commonly given quite in another 

 way. 



" The qualitative analysis gave the following results : — 

 " The finely powdered ore dissolved in nitric acid, with a 

 blueish green colour, leaving a heavy white residue and par- 

 ticles of yellow sulphur suspended in the solution. After 



