368 



Dr. F. Clowes. 



[June 20, 



the surface inwards into the crystalline sulphate. Farther, barium 

 sulphate is known to occur as a pseudomorph of barytocal'cite. 



The abundant presence of calcium sulphate in the sandstone in the 

 neighbourhood of Nottingham points to the probability of the barium 

 sulphate having been formed in situ by the process of double decom- 

 position, and probably from barium carbonate which has been found 

 elsewhere in sandstone beds of the same formation. 



XV. " Deposits of Barium Sulphate from Mine-water." By 

 Frank Clowes, D. Sc., Principal and Professor of Chemistry 

 and Metallurgy in University College, Nottingham. Com- 

 municated by Professor Armstrong, F.R.S. Received 

 June 6, 1889. 



Specimens of remarkable deposits which have formed in the water- 

 boxes of coal-mines in the neighbourhood of Newcastle-upon-Tyne 

 have been for many years in the possession of the Museum of the 

 Durham College of Science. 



A rough analysis has been published by J. T. Dunn (' Transactions 

 of the Newcastle Chemical Society,' vol. 3, p^. 261) of an apparently 

 similar deposit, which was formed during the autumn of 1876 in the 

 Jane Pit at Walker. During this short period the sectional area of the 

 box had been reduced by the deposit from seven and a half square 

 inches to less than half a square inch, and had been in places almost 

 completely closed. The deposit consisted of layers which were 

 alternately white and brown, and was moderately soft. Analysis 

 showed the percentage composition to be 90 of BaS0 4 , 8 of SrS0 4 , 

 1 of CaS0 4 , the remainder consisting mainly of Si0 2 , A1 2 3 , and 

 Fe 2 3 . The water passing though the box at the time of the 

 examination contained no trace of barium or of strontium. 



Another similar deposit was found by Dr. Richardson (.* Brit. 

 Assoc. Report,' 1863) to contain about 90 per cent, of barium 

 sulphate and 3 of calcium sulphate, the remainder consisting of 

 silica, alumina, ferric oxide, and moisture. 



Professor Lebour states the pipes which convey water from the 

 colliery workings of the Newcastle district are frequently entirely 

 blocked in a short space of time with deposits, amongst which barium 

 sulphate is seldom absent, and is often the chief constituent ; and he 

 draws attention to the fact that veins of barium sulphate are by no 

 means uncommon in the coal measures of that district. 



This deposition of barium sulphate is of interest in connexion 

 with the discovery of the sulphate as a cementing material in sand- 

 stone near Nottingham, and as no complete analysis existed of the 

 water-box deposits in the Durham College Museum, Professors 



