432 pkoceedijS'gs or the geological society. [June 28, 



fact that improved drainage had been found to exert a marked in- 

 fluence upon the average number of deaths by consumption in 

 certain districts. The chief result arrived at by an examination of 

 fifty- eight registration districts in Kent and Sussex was, that " wet- 

 ness of the soil is a great cause of consumption ;" and this depends 

 not only upon the perviousness or imperviousness of the soils, but 

 upon their position as regards elevation and slope. 



Discussion. 



Prof. Bbaylet mentioned a paper by Mr. Maekinnon on the same 

 subject, communicated to the Eoyal Society some years ago. 



Dr. Duncan commented on the value of such inquiries, and men- 

 tioned that in Devonshire families living in the valleys were pecu- 

 liarly liable to consumption, while those living on the hills were free 

 from the disease. 



8. On the Volcanic Phenomena of Hawaii. By the Rev. C. G. 

 Williamson. Communicated by Sir R. I. Murohison, Bart., 

 P.R.S., V.P.G.S. 



[Abstract.] 



The author describes the general configuration of the island of 

 Hawaii, and refers especially to the arrangement of the three great 

 volcanic cones which form its highest points. Mount Kea (13,953 

 feet) and Hualalai (10,000 feet) have been quiescent for many 

 years*; but Mount Loa (13,760 feet) is still in a state of constant 

 activity. In the extreme north of the island is the Kohala ridge of 

 cones (about 5000 feet), which appear to have been long extinct. 

 The bases of the three great volcanoes, which stand nearly in an equi- 

 lateral triangle, are united by an elevated plateau forming the centre 

 of the island, sparingly clothed with vegetation, and having many 

 conical hills, from which lava appears to have flowed, scattered over 

 it. In descending from the high grounds there is a belt of woods, 

 in which the vegetation gradually becomes more tropical in its cha- 

 racter ; and this continues to be the case on the lowlands to the coast. 

 The fertile districts are all within the limit of rains ; and here the older 

 lavas, of which the surface consists, are more or less decomposed. 

 The author describes the general characters of the surface, and states 

 that the greatest alteration of the surface has taken place in the 

 northern parts of the island ; hence he concludes that the centre of 

 volcanic energy in the island has gradually been moving southward, 

 the outpourings from the Kohala hills and Mount Kea, which have 

 undergone most alteration, being, in his opinion, the oldest, and the 

 southernmost volcano, that of Mount Loa (including Kilauea), being 

 the only one now in activity. 



The author notices the history of the activity of Mount Loa since 

 the year 1832, when its first recorded eruption took place. A 



* The last eruption of Hualalai took place in 1801. 



