KI^'AHAX — On the CJear'mg of Feat >j Waters. 453 



tlie cylinder tised was 6 inehes lugh, in others 18 iaches ; this vessel 

 of the sample experimented on was compared, on a white surface, 

 with a precisely similar vessel of the same water, which had been 

 previously freed from peaty eolouiing matter by mixing with it a large 

 enough quantity of clay. By so treating any peaty water it was 

 found that the peaty colouring matter could be completely removed, 

 provided only sufficient clay were added. 



Specimen A. — This is a fine cream-coloured clay from the foot wall 

 of the gossan (iron ore) of the Ballymurtagh IS'orth sulphur lode, of 

 which it forms the " selvage." Scattered through it is a small 

 quantity of fragments of iron pyrites and milk quartz ; with water it 

 yields a clear solution, having an acid reaction, and containiag a small 

 percentage of ferrous sulphate and sulphate of alumina. 



Insoluble in hydrochloric acid, 92-51 per cent. 



Perric oxide, 2-35 per cent. 



Alumina, 2-43 per cent. 



It was found to be a most efficient decolouriser of peaty waters. 



TThen added to peaty water, the greater portion settled down almost 

 immediately, but the very fine particles remained in suspension for a 

 considerable time ; when these had subsided, if sufficient clay had been 

 used, the water was very clear ; the top layer of the sediment being 

 brown, as if the colouring matter had been carried down in it. 



If an insufficient C[uantity of this clay were added to the water, 

 several different stages were to be noted. 



A very small quantity of clay altered the colour from a brown to 

 a brown-green, and on adding a little more clay the colour altered to 

 an olive-green. "Wlien more clay was added, but not sufficient to clear 

 the water, a peculiar turbidity or cloudiness formed, which remained 

 persistent, and did not appear to decrease on filtering. TVTien this 

 turbidity was removed by adding more clay, the water was freed from 

 peaty colouring matter. 



"With the specimen of peaty water used in these experiments it 

 was found that working with 1000 cc. of water not very darkly 

 coloured, 1 gramme of clay brought on the brown-green stage; 1-5 

 grammes of clay the olive-green; 2-5 grammes produced a persistent 

 turbidity ; and that 4 grammes removed the cloudiness and the peaty 

 coloujing. 



In order to determine what the active ingredient in this clay might 

 be, some of it was digested iu hydrochloric acid; the insoluble portion 

 after being well washed was found to have very little perceptible 

 action on the peaty water. 



A strong aqueous solution of the clay was prepared (10 grammes 

 of clay to 300 cc. of distilled water) ; this solution with a small quan- 

 tity of the suspended particles was found to be capable of freeing the 

 water fi'om peaty colouring. After filtering the clay solution, it was 

 found that the filtrate possessed the same property. 



2P2 



