74 REPORT — 1851. 



attracts all the impurities in water, or envelopes them in itself, as alum or 

 albumen or lime is used to clear water, but I don't see any of these acting to 

 cleanse the streams to any extent. 



The decoloration of water is not so striking on cultivated laud, because 

 the colour is not so great ; but the colour on the hills which are covered with 

 peat is of a deep brown, and it is curious that we have from such places the 

 finest water. 



I have observed in several places that where the brown streams have been 

 led into reservoirs on the top of the hill, or on the sides of the hill, or even at 

 the bottom of the hill, these reservoirs have continued brown. The canal also 

 from Leeds to Manciiester is brown, although the water is brought down a 

 considerable distance. When these streams are led through artificial conduits 

 or pipes, they do not become colourless ; at least the Sheffield water, although 

 it may clearitself to some extent on the way, is still delivered in the town of 

 a decidedly peaty colour. It is believed that plants obtain carbonic acid by 

 the oxidation of humus and analogous substances ; but it is difficult to believe 

 that in the course of a few miles so much oxidation should take place on the 

 surface of a stream as to remove colour. Many of the streams come out pure 

 from the hill, and, although fi-om a bed of peat of great thickness, are brilliant 

 and colourless. These hills may be found covered above, and in all hollow 

 and flat places, with water which is of a deep brown colour, and strong taste. 

 It has been said that the purification is made by the dashing among the peb- 

 bles and mingling with the air, but the most highly-aerated water is not found 

 in these streams. If this were a very important agent in purifying a short 

 water-course, the streams would have around them an atmosphere of car- 

 bonic acid, or they would sparkle with increased beauty as they proceeded, 

 until they bubbled with carbonic acid. I have never traced a stream in this 

 state of purification ; there is generally an influx of other water from various 

 points which influence its purity, and which probably contribute more to it 

 than the action of the air. It is curious, too, that the streams are brighter 

 in summer, although the water dissolves more peaty matter ; for then stronger 

 solutions of peat are to be found on the hills and in some streams. 



The water, however, may often be observed in tiie act of being cleared. On 

 the top of a hill we see a swamp over which it is difficult and indeed impos- 

 sible to pass without sinking deep enough to become wet ; we go round it, and 

 on every side it is dry. Very often there is one side depressed with a passage 

 for the water down the hill. This passage is often wet all the way down ; the 

 water collects from all sides and forms into a stream. I shall describe a pretty 

 common case as I have observed it at Tintwisle. There was no perceptible 

 passage of water from the swamp, although there was an easy natural flow 

 whenever the water rose high enough to take that mode of discharging itself. 

 This bed, if it may be so called, was at the time I examined it quite dry ; under 

 the turf there was coarse gravel, the surface of the white siliceous rock being 

 considerably broken. The v/ater in the swamp above was very brown ; going 

 further down there issued from the side of the hill a stream of pure water ; 

 the water came from the swamp through the gravel, and went down the side 

 of the hill pure; before getting down it was lost again, entirely disappearing 

 through some more gravel, but it made its appearance again still lower down. 

 It was nearly lost a third time by going into some grass land, which it made 

 very swampy, before it got finally down to the main brook. There was no 

 want of an opportunity to clear itself; the space was not above a few hundred 

 yards in which it sunk twice and re-appeared. After having seen this, I began 

 to find that it was common ; I found two streams near together, each draining 

 a considerable amount of wet land ou a hill neap Buxton, and disappearing 



