230 Annals of the Philosophical Club 



surging sound, audible for a considerable distance on the 

 flanks of the mountain. Replying to his request for an 

 explanation, Mr. Ball and Professor Bonney suggested that 

 an escape of steam, strong but steady, might make the noise 

 and have sufficient force to eject fragments of scoria. Lord 

 Rosse said that he heard a similar noise when he visited 

 Vesuvius. 



Professor Allman described a tubular hydroid, which he 

 had recently examined. It had been dredged up by the 

 Challenger Expedition from a depth of four miles. The 

 unbroken stem must have been about seven feet long, and 

 the polyp at the end, when expanded, about nine inches in 

 diameter ; the corresponding dimensions in a shallow water 

 form being not more than a foot and less than an inch. 

 The stem was formed of an elastic tissue, peculiar in 

 character. The animal was a kind of rose colour. 



June loth, 353rd meeting. M. Cornu (a guest) described 

 a method of controlling by electric magnets a bad astrono- 

 mical clock by a good one. Lord Rosse said he had overcome 

 a similar irregularity in the working of an equatorial clock 

 by the use of electro-magnets with very small battery 

 power. 1 Professor Hughes objected to M. Cornu's method, 

 that no electrical arrangement could overcome the minor 

 errors incident on the employment of electric contacts with 

 the controlling clock. This M. Cornu admitted, but said that 

 such sources of error were so small, that they might be safely 

 neglected where practical not absolute perfection was sought. 



Oct. 28th, 354th meeting. Dr. Huggins exhibited a 

 specimen of the new metallic element Germanium (page 229) 

 discovered by Professor Winkler in an ore of silver. It 

 filled up one of the lacunae in Mendeleeff's series. 



Nov. 25th, 355th meeting. Professor Bonney read part 

 of a letter from Mr. Coutts Trotter, describing a destructive 

 volcanic eruption in Niua-fu, 2 one of the Friendly Islands, 



1 Lord Rosse gave a description in British Association Report, 1884, 

 pages 636-7, to which he referred. 



2 Nature, vol. xxxv. pages 127, 128, gives an account of the eruption 

 and of the glass. 



