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II.— ON A TRAVERTINE FROM BALLISODARE, NEAR 

 SLIGO, CONTAINING A CONSIDERABLE AMOUNT OF 

 STRONTIUM, BY EDWARD T. HARDMAN, f.c.s. 



[Read, May 21st, 1880.] 



Along the shores of _the minor bays which indent the coast 

 near Sligo, there is often a considerable deposit of travertine, 

 owing to the water which trickles over the limestone cliffs, dis- 

 solving a portion of the carbonate of lime, and again depositing 

 it in a porous form on the slope. Travertine is thus found in 

 abundance at Drumcliif Bay, to the north, and at Ballisodare Bay, 

 to the south ; and that at the latter place is interesting from the 

 fact that it contains a very appreciable amount of the rare metal, 

 strontium — probably the only instance in which it is known to 

 occur in a recent calcareous deposit. 



The manner in which I noticed this is sufficiently curious to be 

 mentioned. A silver-lead, and zinc mine is at present being 

 worked close by. A mining captain, who was brought from 

 England to examine this, saw the travertine deposit, declared 

 it to be zinc ore, equal to anything he had seen in Spain, and took 

 some specimens for analysis to England. The owner asked my 

 opinion about it, and was incredulous when I pronounced it to 

 be common travertine. However, eventually it was proved to 

 the satisfaction of himself and his practical friend that it was 

 nothing else. 



As I had been making some researches on the presence of zinc 

 in limestone rocks, I obtained some specimens for analysis, deeming 

 it likely that from its proximity to the zinciferous limestone the 

 deposit might contain a small amount of the metal. It proved, 

 however, to contain not the slightest trace ; but in the course of 

 the examination the presence of strontium was clearly marked. 



It is easy to render this visible. Chloride of strontium is 

 soluble in alcohol, and on ignition gives out the well known 

 crimson colour. 



