196 Proceedings of the Royal Physical Society. 



This average for the silver is probably rather high, since 

 Beringer's assay of a sample from the Beinn Chuirn level 

 gave 



Lead, 68-5%. 



Silver, 3 oz. 12 dwt. per ton. 



Separate assays by both Beringer and Napier, of ore from 

 the main vein where it crosses the Coninish river, show it 

 to be slightly richer there than at Tyndrum. The results are 

 as follows : 



Berin er's i ^^'''^' ^^'^^^ 



° ( Silver, 2 oz. 5 dwt. per ton. 



^ I Silver, 4 oz. 10 dwt. per ton. 



A few other metallic minerals are known to occur at Tyn- 

 drum. Copper pyrites occurs only in very small quantities, 

 as detached grains and crystals disseminated through the 

 veins. Iron pyrites is found accompanying the ores, but not 

 very abundantly, and titanic iron is stated by Thost to have 

 been seen in the mines. Half-way along M'Callum's Level, 

 black and red argentiferous cobalt ore (bloom ?) was found 

 in the hard vein, which at the place contained 4 inches of 

 good ore.^ The cobalt ore was in the centre, with sharply 

 defined bands of galena on each side. This rare mineral 

 only existed as a thin leaf, and exploration of the vein above 

 and below the level failed to show its farther continuance. 

 An assay of the black cobalt gave 



28% cobalt. 



60 oz. silver per ton. 



A trace of red cobalt has also been found at the outcrop 

 of the main vein on Beinn Odhar. 



As secondary or decomposition minerals, we have to note 

 calamine (ZnCOg), which occurs as a white amorphous in- 

 crustation on the sides of the vein in the old workings at 

 Tyndrum. Pyromorphite and malachite are also found as 

 outcrop minerals at the place where the vein crosses the Eas 

 Anie burn. 



^ F. Odemheimer, Highl. Soc. Trans., vol. vii., 1841. 



