138 
which appeared to him irreconcilable with the conclusion 
arrived at by Sir Robert Kane, namely, that in the granite 
of the Dublin and Wicklow granites soda existed in great ex- 
cess, and that only in some cases they contain a small quantity 
of replacing potash; and in which he stated his opinion that 
we could not rest such a conclusion on an argument which 
appeared to him too circuitous, especially when the investi- 
gation might be conducted in a simpler and more direct man- 
ner than that pursued by Sir Robert Kane, namely, the 
analysis of surface water, and the examination of rock speci- 
mens taken from the district ; and that he did not think that 
mineralogists would feel themselves safe in adopting Sir 
Robert Kane’s conclusions, until it was supported by the re- 
sults of experiments made directly on the felspars themselves. 
‘‘ Feeling the importance of this suggestion, it occurred 
to me that good service might be done to the sciences, both 
of mineralogy and geology, if I were to undertake the che- 
mical examination of the minerals whose character was called 
in question, in order, if possible, to arrive at the determination 
of such an interesting question. And that I might not fall 
on these ‘ particular spots where orthose or potash-felspar was 
to be found,’ I cast my eye over the map of Dublin and its 
adjacent county, and selected a number of localities pretty 
evenly distributed over the range commencing at Dalkey and 
extending as far as Glenmalur, situated on the flanks of Lug- 
na-quilla, which is about thirty-six miles from Dublin. 
‘The results of these analyses I beg to lay before you. 
The distances of the localities from which the specimens were 
taken may be stated as follows :— 
From Dalkey to Three Rock Mountain, . . . . 5 miles. 
55 Three Rock Mountain to Lough Bray, .5 ,, 
»» ~duough Bray to Lough Dan, . . 2. 25. es 
»» Lough Dan to Glenmacanass, ...... Rivss 
s» Glenmacanass to Glendalough, ..... Ges, 
», Glendalough to Glenmalur, ....... 2 
39 
