56 
BRITISH ASSOCIATION.- 1835 . 
ignorance and wilfulness of the workmen, proposed a plan for the 
security of the lamp from injury and mismanagement. 
Professor Graham noticed with regard to safety lamps, on the 
theory of which he has been some time engaged, that wire gauze is 
rendered much more impervious to flame by being first dipped in an 
alkaline solution, which also protects the wire from oxidation. 
On a new Electrometer . By William Snow Harris, F.R.S ., fyc. 
Report of the Committee appointed to consider the subject of Chemical 
Symbols. By Dr. Turner. 
[This Report, with the remarks of several of the members of the 
Committee, will appear in the next volume of the Transactions of 
the Association.] 
GEOLOGY AND GEOGRAPHY. 
On the Geological Map of Ireland. By R. J. Griffith. 
Mr. Griffith presented his Geological Map of Ireland, the result 
of many years’ research and labour, assisted in part by the publica¬ 
tions of Weaver, Conybeare, Buckland, and Berger. Mr. Griffith, in 
pointing out the inaccuracies of existing maps of Ireland, dwelt on 
the advantages which will be derived from the publication of the Ord¬ 
nance maps of Ireland, four counties of which have now appeared. 
At present great difficulties attend the allocation of geological phse- 
nomena, which are frequently misplaced in relation to each other, 
from the necessity of following the defects of the old maps. Mr. Grif¬ 
fith, as an example, stated that in Arrowsmith’s map, Benwee Head 
is placed twenty miles north of the parallel of Sligo, though it 
is actually due w*est of that town. The remarkable position of 
the mountain masses was first pointed out. They occur on the 
margin of the island, and inclose the great central limestone plain; 
an arrangement which shortens the courses of the rivers, rising as 
they do in the higher grounds, and rapidly descending to the sea. 
The Shannon is an exception, having a course of 140 miles; but it 
also is affected by the peculiarity alluded to, its stream falling eighty 
feet in the first twenty miles of its course, and only eighty feet more 
in the remaining 120. On the great plain which occupies the centre 
of the island numerous beds of gravel occur, called Escars, which 
though constant in direction when considered in reference to small 
spaces, are variable when the comparison extends over greater 
limits. Mr. Griffith considers the great bogs as due to these accu¬ 
mulations of gravel, which, by damming in the water, facilitate the 
growth of Sphagnum palustre. Under the bogs are deep deposits of 
marl, underlaid by clay and gravel, which further support the idea 
of ancient lakes. The marl was stated to be in one instance fortv feet 
V 
