[ 206) | 
XX. 
ON A GRAPHITIC SCHIST FROM CO. DONEGAL. By 
RICHARD J. MOSS, F.C.S., F.LC. 
[Read Junz 21; Received for publication Junz 23; Published August 24, 1893.] 
GRAPHITE is recorded as occurring at a number of places in Ire- 
land. Mr. G. H. Kinahan, in his Paper on Irish Metal Mining, 
mentions localities of the mineral in the counties Clare, Donegal, 
Kilkenny, Mayo, Tipperary, Wexford, and Wicklow. I have 
been unable to find a published analysis of the graphite from any 
of these localities; accordingly, I take the opportunity of placing 
on record the chemical composition of a graphitic mineral which 
has recently come under my notice. The specimen is from Glen- 
down, in the parish of Gartan, Letterkenny, Co. Donegal, a 
locality in which the occurrence of graphite has not previously 
been recorded. The rock was found in large quantity by a Mining 
Company in sinking a shaft in the metamorphic schists. The 
specific gravity of the rock is 2°662, and it yielded the following 
results on analysis :— 
H20, expelled at 100°C., : : 0:98 
a S a red heat, . c é 3°68 
Carbon, : : : : E 3°15 
Sulphur, : : j é 4 4:03 
Ash, allowing for the displacement of sulphur 
by oxygen, : : j 5 SENG) 
99°73 
I found the ash to consist of-— 
$102, . : . . . 58°91 
‘ATOs, . 19°87 
Fe203, . 5 5 . . 7°40 
CaO, : é c P : 4°86 
MgO, : 5 - 1:68 
Naz,0, 5 . A 2 x 3°54 
K,0, : ; ; : : 3°73 
99°94 
With traces of Mn and Ni. 
1 Scientific Proceedings, Royal Dublin Society, N.S., vol. v., p. 250. 
