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XL VI.— THE BLACK MAKBLE OF KILKENNY. By W. N. 

 HARTLEY, F.B. S., Professor of Chemistry, Royal College 

 of Science, Dublin. 



[Read, February 15, 1887.] 



This well-known marble is highly esteemed on account of its jet- 

 black appearance and the high polish which it is capable of receiv- 

 ing. Last April I visited the quarries from which it is procured, 

 and observed certain properties belonging to it of which I can find 

 no description. It is mentioned in Sir Robert Kane's work on 

 "The Industrial Resources of Ireland" that the exposed and 

 weathered surfaces of the rock possess a yellow ochreous colour. 

 This might be due to the colour of the freshly-hewn stone being 

 caused by the presence either of ferrous sulphide or of ferrous 

 carbonate, which, in presence of carbonic acid and air, became dis- 

 solved and oxidised. The disappearance of the black colour from 

 the surface was remarkable. On striking a block of the marble 

 with a hammer or large stone it emitted a ringing metallic sound. 

 When portions were broken off, the fractured surface smelt of sul- 

 phuretted hydrogen. Under similar circumstances the German 

 "Stinkstein" is said to smell of bituminous matter. The con- 

 stituents of the mineral were determined by Mr. J. E. Purvis, a 

 student in the Royal College of Science ; the results of his exami- 

 nation are here given : — 



Chemical Analysis. 



When the mineral was finely powdered and thoroughly mixed 

 its colour was a little lighter, but still what may be described as 

 black. Carbon dioxide was determined by Fresenius and Will's 

 method : the escaping gas smelt of sulphuretted hydrogen. 



Estimation of Sulphuretted Hydrogen. — It was found by Mr. 

 Fred Ibbotson, who made a qualitative examination of the 

 mineral, that sulphuretted hydrogen was liberated by acetic 

 acid, also that precipitated ferrous sulphide is decomposed by 

 acetic acid ; therefore nothing could be learnt by dissolving the 



