184 PROCEEDINGS OF SOCIETIES. 



Presented by 



Beitracr zu einer MonoE^rapliie der Sciarinen, von Joh. 



Winnertz in Crefeld . . . Author. 



The Microscope, 4tli edition, by Dr. Carpenter . Ditto. 



Die Diatomeen der Hohen Satra bearbeit, von J. Seliu- 



niann . . . . , Ditto. 



Diagnosen der in Ungarn und Sclavonien Bisher Beo- 



bachteten Gelasspfianzen, Verliandlunofen der kai- 



serlich-koiii^licben Zoologisch-botanibchen Gessell- 



schaft in Wien .... Ditto. 



The attention of the Society was called to a set of models of the 

 gizzard of the PhilocUna roseola, made by the Hon. and Rev. the 

 Lord Sydney Godolphin Osborne. 



Mr. Heisch read a description of improvements be had effected 

 in Nacbet's Stereo-pseudoscopic Binocular Microscope. (See 

 'Trans.,' p. 112.) 



Mr. Bbooke explained the action of Nachet's construction. 

 _ A paper was then read " On Fungoid Growths in Aqueous Solu- 

 tions of Silica, and their Artificial Fossilization," by William 

 Chandler Roberts, F.C.S., Associate of the Royal School of 

 Mines, and Henry J. Slack, F.G.S., Sec. R.M.S. "(See ' Trans ,' 

 p. 105.) 



Mr. Roberts gave some further account of the mode of pre- 

 paring silica solutions and their behaviour. 



Mr. Barff, F.C.S., stated that, in his experiments referred to in 

 the paper, every care was taken to exclude dust. The silica solution 

 was dialysed in a vegetable parchment dialyser covered with filterino- 

 paper. After the potash and acid had passed away, the solution of 

 silica was filtered. Some growths were found on the filter, and 

 growths came abundantly in the solutions kept in University 

 College Laboratory. Some gelatinized specimens contain dozens of 

 the fungoid plants. As the gelatinized silica dries, the process does 

 not seem to go on by steady evaporation. He had observed a layer 

 of water on the top of some silica in a flask, as if it had been squeezed 

 out from the mass below. Peculiarities in the mode of drying mio-ht 

 account for the fungoid branches keeping their form during the 

 contraction of solidification. From some experiments he thought 

 that the presence of alkalies prevented these fungoid growths. 

 Where the growths had occurred the plants had no nutriment but 

 what they might derive from silica, air, and water. He thought 

 further observations might lead to a better understanding of the 

 part played by silica in agriculture. He considered that the 

 importance of silica had not been fully recognised hitherto. 



Mr. Browning said that he had heard the vegetable appearance 

 compared with the peculiar fractures produced by electrical perfora- 

 tions in glass, but their actual growth was conclusive as to their 

 character. 



Mr. Slack observed that the foliated aspect of glass perforations 



