596 



REPORT — 1889. 



session, proved the undoubted presence of barium, though entirely in the form of 

 carbonate. Since this sandstone consists of the keuper basements beds, and belongs 

 therefore to the same geological period as the beds at Bramcote, it becomes an interest- 

 ing question to geologists whether barium compounds are in any way characteristic 

 of the keuper sandstones. Bischof describes sandstone of character similar to the 

 above as occurring in Miinzenberg in the Witterau, and further mentions instances 

 of disintegrated granite and of sand and clay being cemented by barium sulphate. 



In discussing the curious nature of this sandstone with Professor Bedson, D.Sc, 

 I was informed of the remarkable deposits, consisting largely of barium sulphate, 

 which are rapidly formed in the pipes and water-boxes connected with the pumps 

 of the Durham collieries. Mr. J. T. Dunn ' mentions an instance of this deposition 

 occurring so rapidly in the Jane Pit at Walker that a pipe of seven and a half 

 square inches section was almost completely closed by it in the course of one 

 autumn. Analysis of this deposit showed that it contained 90 per cent, of BaSO^, 

 8 of SrS04, 1 of 0aSO4, and of small quantities of SiO^, Al^Oj, and Fe.fiy 



Dr. Richardson ^ had already found a similar composition for an analogous pipe 

 deposit. The further examination of these deposits appeared to me of interest in 

 connection with the occurrence of the sandstone already referred to. I have accord- 

 ingly made full analyses of several characteristic pipe deposits kindly furnished to 

 me from the Durham College Museum by Professors Bedson and Lebour. The 

 results obtained were as follows : — - 



Professor Bedson ^ and others have found barium chloride to be a common con- 

 stituent of the colliery waters of the Durham colliery district, and it would appear 

 possible that the barium present in this form might be precipitated as sulphate in 

 a more or less coherent state by coming into contact with water charged with sul- 

 phates resulting from the oxidation of the pyrites in the coal. The occurrence of 

 barium sulphate in the Nottingham sandstone and in the Durham collieries may, 

 however, have been due to the alteration into sulphate which barium carbonate 

 can undergo when in contact with solutions of sulphates. Bischof has proved this 

 by laboratory experiments {loc. cit.), and Haidinger has observed the process occur- 

 ring in natural deposits of mountain limestone at Alston Moor.* The original 

 deposit may therefore have been one of barium carbonate from water containing 

 the bicarbonate in solution, and in the mine this may have undergone alteration 

 from the products of oxidation of pyrites or from other soluble sulphates. In the 

 case of the Nottingham sandstone the calcium sulphate which is present in abun- 

 dance may have effected the change. Bischof also states that a hot spring may 

 contain BaCOj and Na3S04 together in solution, and deposit BaSO^ only on cooling by 



' Trans. Newcastle Chera. Soc. vol. iii. p. 261. 

 » Brit. Assoc. Report, 1863. 

 ' Journ. Soc. Chem. Tnd. vol. vi. p. 712. 

 * Pogg. Ann. vol. ii. p. 376. 



