596 Proceedings of the Royal Irish Academy, 



LXXXI. — Repoet ojs" the Cieaeln'g of Peatt "Watees. Paet II. 

 By Geeeaed A. Etxahan. 



[Eead, April 24, 1882]. 



Introductory Remarks. 



In the previous Eeport^ laid before the Academy it was shown, after a 

 coloronietric examination and comparison of certain streams, " that 

 peaty colouring matter does not seem to be removed by direct oxida- 

 tion." Since then I have been enabled, through the courtesy of Pro- 

 fessor Hartley, P.P.S.E., &c., to make in his laboratory, at the Royal 

 College of Science, analyses of samples of peaty waters in which there 

 were facilities for oxidation, viz., aeration when falling from a great 

 height. 



In this Report it is proposed to lay before the Academy — First, 

 the results of these analyses, and, in continuation, the analyses of some 

 waters that receive a large amount of mineral drainage, with a short 

 sketch of the nature of this di-ainage, and its effect on the peaty waters. 



In the analyses the method adopted for estimating the organic car- 

 bon and nitrogen was a modification of Dittmar and Robinson's process. 



The nitrogen, as nitrates and nitrites, was estimated in the follow- 

 ing manner : — 



100 cc. of the water was boiled for a short time ; then, when cold, 

 a small piece of clean platinum foil and some magnesium ribbon were 

 put in, with a fragment of recently fused sodic chloride ; after stand- 

 ing about 12 hours the ammonia was distilled off, and estimated by the 

 JN'essler test, and from this the nitrogen calculated. 



This process is especially applicable to the estimation of very small 

 quantities of nitrates and nitrites. 



Waters hecoming much Aerated. 



The first waters to be described were taken from the Dargle river, 

 at Powerscourt waterfall, in the autumn of last year (October, 1881). 

 The day was bright, fine, and warm ; but during the two previous days 

 misty rain had fallen on the hills, so that there was a slight flood in 

 the river, but it was not at all turbid, although it was stated by Lord 

 Powerscourt's game-keeper, who accompanied me, to be unusually peaty. 



The first sample was taken a short distance above the fall, at a 

 point where the river flowed rapidly through a deep channel, four feet 

 wide, in the solid rock (mica schist). Prom this to the foot of the 

 fall, where the second sample was taken, the river flowed altogether 

 over solid rock, excepting a few loose boulders and some coarse gravel 

 lying in the channel above the top of the fall. ISo visible drainage of 

 any kind enters the river between these two points, which are sepa- 

 rated, horizontally 800 feet, and vertically 360 feet. 



^ Vide ante, p. 447. 



