98 



Scientific Proceedings, Royal Dublin Society. 



liumic acid results in an insoluble compound to which he assigns 

 the formula C54H47NO19, which he states may be regarded as 

 derived from humic acid, thus : — 30i 8 H 16 7 + NH 3 - H 2 0. He 

 regards this compound as comparable to aspartic acid. 



When I first became aware of the nature of the Sluggan speci- 

 men I decided to determine its acidity by the method devised by 

 Dr. Tacke for determining the acidity of peat and soil. I sub- 

 sequently ascertained that this method had already been applied to 

 dopplerite by Professor Immendorff, who obtained the following 

 results : — 



Assuming that Mayer's formula for humic acid C 17 H 1B 8 is 

 correct, that it contains one carboxyl group, and that the liberation 

 of carbonic acid in Tacke's method is due simply to displacement 

 by humic acid, the above results correspond to the following 

 quantities of free humic acid in 100 parts of the dry substance 

 from the places mentioned : — 



Elizabethfehn, . 



Pilatus, 



Papenburg, 



70-48 

 41-52 



36-43i 



I have determined the acidity both of Sluggan dopplerite, and 

 of the peat immediately associated with it, employing the following 



1 These figures I quote from a private communication from Prof. Immendorff, who 

 informs me that an error crept into his former calculations, and that the figures origin- 

 ally published in Mitteil. d. Ver. z. Ford. d. Moorkultur, 1900, p. 232, are wrong. 



