Hartley — On the Black Marble of Kilkenny. 487 



mineral in acetic acid. The gases evolved by hydrochloric 

 acid acting upon ten grams of the substance were passed 

 through two U tubes containing acidulated solution of copper 

 sulphate : a brown precipitate formed only in the first limb 

 of the first tube ; this was collected on a filter, washed, dried, and 

 weighed. It was considered that as the quantity collected was very 

 small, and water was contained in the mineral, that the sulphu- 

 retted hydrogen was in solution in fluid enclosures too small to be 

 visible, and that possibly it was present as calcium sulphydrate. 

 A large quantity of the substance was crushed under distilled 

 water, and on testing the liquid with lead paper a black stain of 

 lead sulphide was obtained. The aqueous solution was filtered; 

 the filtrate was evaporated to dryness, and a light-brown residue 

 was left. Examined with the spectroscope, the residue was found 

 to contain a compound of calcium only. Another portion, crushed 

 under water, filtered, and treated with ammonium chloride, am- 

 monia, and ammonium oxalate, yielded a white precipitate, small 

 in amount, and consisting of calcium oxalate. A portion of the 

 residue left after evaporation of the aqueous solution was oxidised 

 with nitric acid, and tested with barium chloride, by which treat- 

 ment a precipitate of barium sulphate was obtained. 



Copper. — After solution of the mineral in hydrochloric acid 

 and evaporation to dryness, to separate silica in the usual way, a 

 eurrent of sulphuretted hydrogen, passed for some time through the 

 hot solution, separated a small quantity of copper sulphide. This 

 was filtered, washed, dried, transferred to a crucible, heated with a 

 few drops of strong nitric acid, and the iron precipitated by ammo- 

 nium chloride and ammonia, dried, and weighed. 



Calcium and Magnesium. — These were precipitated in the usual 

 manner. 



Organic Matter. — The black residue, insoluble in hydrochloric 

 acid, was collected on a weighed filter, washed well with hot water, 

 and dried at a temperature of 100° 0. A weighed portion of this 

 was placed in a platinum boat, and burnt in a current of oxygen ; 

 a very slight residue, apparently ferric oxide, remained. The carbon 

 dioxide and water were collected in the usual manner and weighed. 

 The organic matter was almost entirely carbon : no hydrogen could 

 be calculated from the amount of water collected, hence the car- 

 bonaceous matter was apparently of the nature of anthracite. 



