Lint of Coiifribufors. vii 



PAGE 



SoLLAs, W. J., LL.D., F.R.S., and G. A. J. Cole, F.G.S. 



The Origin of certain Marbles : A Suggestion, . . .124 



SoLLAs, W. J., LL.D., F.R.S. 



On a Fragment of Garnet Hornfels, ..... 48 



On Homotccchus {ArchcBocidaris Harteana, Baily), a New 

 Genus of Palaeozoic Ecbinoids, ..... 152 



On the Structure and Origin of the Quartzite Rocks in the 

 Neighbourhood of Dubhn (Plate XV.), . . . .169 



Stoney, G. Johnstone, M.A., D.Sc, F.R.S. 



On the Cause of Double Lines and of Equidistant Satellites 

 in the Spectra of Gases (Abstract ; see Transactions, 

 Royal Dublin Society, Vol. IV., Part XL), . . .201 



Analysis of the Spectrum of Sodium, including an Enquiry 

 into the True Place of the Lines that have been regarded 

 as Satellites (Plates XVI. and XVIL), . . . .204 



On the Appreciation of Ultra-visible Quantities, and on a 

 Gauge to help us to appreciate them, .... 530 



Why there is no Atmosphere on the Moon (Abstract ; see 

 Transactions, Royal Dublin Society, Vol. V., Part I., 

 p. 1), 546 



WiGHAM, J. R. 



Improvements in Lighthouse Lights, with an Exhibition of 

 proposed New Burners and their Flames, . . . 147 



