110 Mr Haidinger on a Remarkable Variety of Boracite. 



shale, and still the gas continued to escape through the shale 

 from the floor of the pit ; in quantities, however so small, as 

 not to prevent the miners from working all day ; they now 

 complain more of the loathsome sulphureous odour, which they 

 still experience at the bottom of the pit, than of any difficulty 

 in breathing* The pit is now 100 feet deep, and no wa- 

 ter has beeen found. Its mouth is situated about fifty yards 

 from, and is elevated about twelve feet above high water mark. 



I collected all the information, now communicated, from 

 the workmen, four of whom were eye-witnesses of the events. 

 It will give me much pleasure to make any further inquiry 

 you may think necessary.* 



I have the honour to be, 

 Dear Sir, 



Yours most faithfully, 



Leith, 23d May 1825. John Coldstream. 



Art. XXIII. — Notice of a Remarkable Variety of Boracite. 

 By William Haidixger, Esq. F. R. S. E Communi- 

 cated by the Author. 



A very interesting variety of Boracite hasbeen lately discovered 

 at Liineburg, in crystals of the form represented in the annexed 

 figure. Dr Turner has favoured me with a specimen which 

 he had received from Professor Stromeyer of Gottingen. The 

 crystals are engaged in a mixture of gypsum and anhydrite, 

 both of them, but particularly the latter, crystallized in the 

 drusy cavities, distributed throughout the rock. The general 

 appearance of the crystals is that of a combination of the hexa- 

 hedron, the octahedron, and the dodecahedron, in which the 

 faces of the octahedron take the greater share in limiting the 



* Since the above was written, quantities of the gas have several times 

 suddenly rushed from the bottom of the bore, with a noise like thunder, 

 but a sufficient quantity has not again been accumulated to admit of explo- 

 sion on the approach of fire. It was attempted to collect in bottles some 

 of the gas on those occasions ; but in none of these (one of which Dr Tur- 

 ner was so kind as submit to a careful examination) could anything but 

 the common ingredients of the atmosphere be detected. It is probable, 

 however, that the explosive gas was carburetted hydrogen. — J. C. 



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