454 Proceedings of the Royal Irish Academy. 



From these two experiments it is evident that it was something 

 dissolved ont of the clay that acted on the peaty matter, and that the 

 insoluble portion had very little to do with it. 



As on examining the clay solution it was found that it contained 

 ferrous sulphate, a solution of ferrous sulphate was prepared ; and of 

 this a few di'ops caused a peculiar turbidity to form, then a brown pre- 

 cipitate settled to the bottom, and the water was found to be free 

 from peaty colouring matter. 



Sulphuric acid, hydrochloric acid, and nitric acid were also found 

 to precipitate the peaty colouring matter to some extent. 



Specimen B. — A disintegrated light yellow red steatitic shale, 

 occurring in a dyke-like mass in the townland of Ballykillageer : — 



It yields with water a turbid yellowish Kquid, which clears on 

 standing, the suspended particles subsiding ; the solution is neutral to 

 test paper, and none of the clay appears to be dissolved in it. 



Insoluble in hydrochloric acid, 78-28 per cent. 



Perric oxide, 8' 12 ,, 



Alumina, 7"96 ,, 



Manganese, trace. 



This specimen also cleared peaty waters of their colouring matter, 

 though not so well as the last. "When sufficient clay was added to 

 entirely clear the water (25 grammes in 1000 cc), the top layer of 

 the sediment, which was formed of the fine particles that had remained 

 longest in suspension, was more deeply coloured than the rest. 



When an insufficient quantity of clay was added to the peaty 

 water, the changes were similar to those taking place with the last 

 specimen, viz., an alteration of the brown colour to a deep olive- 

 green ; after which a cloudiness or turbidity appeared, but it dis- 

 appeared when sufficient clay had been added. 



On digesting aboiit 5-5 grammes of this clay with water, filtering 

 and evaporating the filtrate to dryness, only a very minute inorganic 

 residue is left, showing that there is very little soluble matter in the 

 clay. 



Specimen S. — A bluish clay occurring in a clifi on the Ballyna- 

 gappoge brook. During floods a considerable portion is washed into 

 the stream, and it probably assists in the decolourising of the waters of 

 this brook, as mentioned in the field notes, p. 450, supra. 



Digested with hydrochloric acid, it gives — 



Insoluble portion, 81 '79 per cent. 

 Ferric oxide, 6"72 ,, 



Alumina, 6'47 ,, 



"When mixed with peaty water it seems capable of removing the 

 brown tint, but incapable of removing the greenish tinge; the water, 

 however, remains slightly turbid. 



