Moss — Chemical Notes on a Stone Lamp from Ballijbetagh. 165 

 I suggest the following as the probable composition of this saline 



matter :- 



Sodium chloride, 



51-55 



Sodium sulphate, 



11-66 



Ammonium chloride. 



10-57 



Calcium sulphate, . 



8-26 



Magnesium sulphate. 



3-35 



Iron sulphate, 



4-21 



Sodium not accoimted for in the above salts, 177 



Water and organic matter, . 



8-63 



100-00 



The presence of this easily soluble saline matter, consisting mainly of 

 common salt, proves conclusively that the vessel could not have been exposed 

 to the weather. It is highly probable that the vessel had in fact remained, 

 as my informant supposed, in possession of his family for a long time; and I 

 suggest that it had been used as a lamp by some of his predecessors. 



Professor Henry J. Seymom- has been good enough to make a petrological 

 examination of some fragments of the rock of which the cup is made. He 

 identified a white and a green chloritic mica, plagioclase, granules of quartz, 

 and flakes of kaolin, and fx-om these results and the general appearance of the 

 rock, he concludes that it is a decomposed schistose epidiorite or diabase. It 

 is probable that the vessel was made from a boulder ; the nearest locality 

 from which the boulder might have been derived is Bohernabreena, which is 

 about eight miles north-west of Ballybetagh. 



An analysis of a small portion detached from a cavity in the base of the 

 vessel gave the following lesults : — 



Silica, 









5r86 



Alumina, 









18-92 



Ferrous oxide, 









1-31 



Ferric oxide. 









9-22 



T.ime, 









trace 



Magnesia, 









9-83 



Potash, 









•31 



Soda, 









2-51 



Water, 









6-19 



100-15 



R.I.A. PROO., VOL. XXVIJI., SECT. 



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