KiNAHAN — On the Clearing of Peaty Waters. 457 



placed at the bottom of a vessel containing peaty water. There is a 

 marked analogy between this layer of clear water at the bottom of the 

 vessels, and that mentioned by Professor Hartley, as occurring at the 

 bottom of some of the Scotch lakes. 



Magnesia was not found to affect the peaty colouring ; pure car- 

 bonate of lime has only a very slight effect on the peaty colouring ; 

 pounded up chalk and limestone were found to reduce the tint slightly. 



A hard water has only a very slight effect on the peaty colouring ; 

 but, on precipitating the carbonate of lime in the mixed waters, either 

 by boiling or by adding to it lime-water, a large quantity of the peaty 

 colouring is removed. 



Lime-water added to a peaty water precipitates the peaty colouring. 



By mixing some fresh hydrate of alumina and water together, filter- 

 ing the solution, and adding some of the filtered liquid to some peaty 

 water, the colouring matter was precipitated. By similarly treating 

 hydrates of iron and manganese no precipitation of peaty matter was 

 obtained. 



In the field it was remarked that during frost, or when there was 

 considerable snow in the drainage area of the river, the waters did not 

 run nearly so peaty as at ordinary times, and often ran quite colour- 

 less, and mountain streams which at other times were deeply tinted were 

 under these circumstances perfectly clear. Therefore some peaty water 

 was frozen in tall cylinders, and it was found that although the peaty 

 colouring matter was not precipitated, yet the behaviour was interest- 

 ing, as the colouring appeared to resist freezing. 



In such water, when the freezing took place gradually from above 

 downwards, a layer of deeply coloured peaty water collected at the 

 bottom, but the water resulting from the thawing of the small cylinder 

 of ice was quite free from peaty colouring. When the freezing took 

 place from the sides, a central core of darkly coloured peaty water 

 collected. When the solidification took place rapidly, the darkly- 

 coloured peaty water appeared enclosed in small patches through the 

 block of ice, as though squeezed out of the freezing water, and concen- 

 trated in these patches which did not seem to freeze. 



On freezing a cylinder of peaty water gradually from above down- 

 wards, then taking out the block of ice, leaving the layer of deeply 

 coloured water at the bottom of the cylinder, refilling with peaty water 

 and again freezing, and repeating this several times, a very small quan- 

 tity of brown sediment settled down to the bottom. 



Boiling peaty water gently for some time does not precipitate the 

 peaty colouring matter ; before a boiling temperature is reached, bub- 

 bles of gas escape from the liquid. 



The discolouration which results from boiling peat for some time 

 with distilled water can be almost entirely removed by filtering; but by 

 adding a little ammonia to the water before warming, a large quantity 

 of colouring matter becomes dissolved, giving the water a very dark 

 colour. This colour is removed neither by filtering nor by boiling the 

 water for a considerable time. 



