XVlii REPORT—1840. 
1839. 
Report on the present state of our knowledge of Refractive 
Indices for the Standard Rays of the Solar Spectrum in dif- 
ferent media, by the Rev. Baden Powell, M.A., F.R.S., F.G.S., 
F.R.Ast.S., Savilian Professor of Geometry, Oxford. 
Report on the distribution of Pulmoniferous Mollusca in the 
British Isles, by Edward Forbes, M.W.S., For. Sec. B.S. 
1840. 
Report on the recent progress of discovery relative to Radiant 
Heat, supplementary to a former Report on the same subject 
inserted in the first volume of the Reports of the British Asso- 
ciation for the Advancement of Science, by the Rev. Baden 
Powell, M.A., F.R.S., F.R.Ast.S., F.G.S., Savilian Professor 
of Geometry in the University of Oxford. 
Supplementary Report on Meteorology, by James D. Forbes, 
Esq., F.R.S., Sec. R.S. Ed., Professor of Natural Philosophy in 
the University of Edinburgh. 
—— —____—. 
The following Reports of Researches undertaken at the request 
of the Association have been published, viz. 
1835. 
On the comparative measurement of the Aberdeen Standard 
Scale, by Francis Baily, Treasurer R.S., &c. 
On Impact upon Beams, by Eaton Hodgkinson. 
Observations on the Direction and Intensity of the Terrestrial 
Magnetic Force in Ireland, by the Rev. H. Lloyd, Capt. Sabine, 
and Capt. J. C. Ross. 
On the Phenomena usually referred to the Radiation of Heat, 
by H. Hudson, M.D. 
Experiments on Rain at different Elevations, by Wm. Gray, 
jun., and Professor Phillips. 
Hourly observations of the Thermometer at Plymouth, by 
W.S. Harris. 
On the Infra-orbital Cavities in Deers and Antelopes, by A. 
Jacob, M.D. 
On the Effects of Acrid Poisons, by T. Hodgkin, M.D. 
On the Motions and Sounds of the Heart, by the Dublin 
Sub-Committee. 
On the Registration of Deaths, by the Edinburgh Sub- 
Committee. 
1836. 
Observations on the Direction and Intensity of the Terres- 
