ROYAL DUBLIN SOCIETY. 
HUNDRED AND FIFTIETH SESSION, 1880-81. 
MINUTES OF PROCEEDINGS. 
Monpbay EVENING, NOVEMBER 15TH, 1880. 
Sections I. and II.—Physical and Expervmental Science, and 
Applied Science. 
With which the “ Dublin Scientific Club’’ is associated. 
WENTWORTH ERCK, LL.D., F.R.A.S., in the Chair. 
The following Communications were laid before the Section :— 
C. E. Burton, B.A., F.R.A.S., and Howarp GRuBB, M.E., F.R.A.S.—“A 
New Form of Ghost Micrometer for Astronomical Instruments.” 
(Proceedings, Vol. III., N.S., Part 1.) 
WIM Smita, c.e.—“ Preliminary Note on the Manufacture of Paper 
from Purple Melic Grass (Molinia coerulea). 
(Proceedings, Vol. ITI., N.S., Part I.) 
G. F. Firz@eRAp, F.T.c.D.—‘ Recent Advances in Physical Science” :-— 
1. Captain Galton’s mode of determining the heights and distances of 
Clouds. 
2. Professor Osborne Reynolds’s Theory of how Oil stops the pro- 
pagation of Waves on the surface of Water. 
Section ITI.—Natural Science. 
(With which the “ Royal Geological Society of Ireland” is 
associated. : 
G. H. KinaAHAN, President R.G.S.L, in the Chair. 
The following Communications were laid before the Section :— 
R. J. Ussuer and Dr. LerrH ApAms, F.R.s.—“ Explorations in the 
Bone Cave of Ballynamintra, near Cappagh, Co. Waterford ;” with a 
description of the Physical Features of the vicinity, by G. H. Kryanay, 
President, B.G.8.1. 
(Transactions, Vol. L., Part XIV., i press.) 
Percy E. Frexe.— North American Birds in Europe.” 
(Proceedings, Vol. III., N.S., Part L) 
Davip M‘Arpite.—* Notes on some new and rare Irish Hepatice.” 
(Proceedings, Vol. III., N.S., Part I.) 
