Proceedings, dx.,for 1886. 263 



The President then asked Mr. Lucas to read Mr. W. M. Bale's 

 paper, entitled "The Genera of the Plumulariidje, with Observa- 

 tions on Various Australian Hydroids." 



Mr. Lucas read an abstract of the paper, and, after a few remarks 

 from some of the members, the proceedings closed. 



September dth, 1886. 



Present, the President, Professor Kernot, M.A., C.E. (in the 

 chair), and 30 members and associates. 



Mr. Walter E. T. Powell, of Goode Island, Queensland, was 

 duly elected by ballot as a country member. 



The President announced that the Council of the Society had 

 recommended Dr. R. D. M. Verbeek, of Buitenzorg, Java, as an 

 honorary member of the Society, under clause 24 of the laws of 

 the Society. 



Dr. Verbeek, having been duly nominated by Dr. Jamieson and 

 Mr. Arthur Lynch, was unanimously elected by ballot an honorary 

 member of the Society. 



The President called on Mr. G. S. Griffiths to read his paper 

 " On the Official Reports of the Tarawera Eruption." Accepting 

 the official description of the occurrence, he disputed the conclusions 

 arrived at. He thought it was incorrectly described as a purely 

 hydrothermal phenomenon, and as a merely local movement; and 

 alleged that the chemical composition and plutonic nature of the 

 ejecta were inconsistent with such a conclusion. 



Captain F. C. Rowan had just returned from New Zealand, 

 where he had heard from Dr. Hector a more detailed description of 

 the eruption and fuller reasons for his conclusions. He thought 

 that until the complete report had been received it was premature to 

 criticise the instalment of it which had come to hand. 



The President reported some observations made by himself at 

 Vesuvius on the periodicity of the puffs of steam twice in a minute. 

 A similar periodicity in the emission of steam had been observed in 

 other active volcanoes. 



Mr. Lucas questioned the correctness of the chemical composition 

 attributed to the ejecta, which he considered andesitic rather than 

 obsidian. Only surface and light materials having been ejected, 

 favoured Dr. Hector's view of the eruption not being deep-seated. 

 He did not think that generation of steam was an indispensable 

 cause of volcanic eruptions. 



Mr. Thompson remarked on the general proximity of volcanoes 

 to the seaboard, and inquired as to the local geology at Tarawera. 



Dr. Ralph showed Mr. Percy Smith's map of Tarawera. 



Mr. White remarked that explosions were not always accom- 

 panied by low atmospheric pressure. 



After some remarks froin Mr. Selby and Mr. Lynch, 



