184 PROCEEDINGS OF SOCIETIES. 



Presented by 



Beitra? zu einer Monographie der Sciarinen, von Joli. 



"Winnertz in CrefeW . . . Autlior. 



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



Die Diatomeeu der Holieu Satra bearbeit, von J. Schu- 

 mann ..... Ditto. 



Diagnosen der in Ungarn und Sdavonien Bisher Beo- 

 bachteteii Gelasspflanzen, Verhandlungen der kai- 

 serlich-koniglichen Zoologisch-botauischen Gessell- 

 schaft in Wien .... Ditto. 



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

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

 Lord Sydney Godolphin Osborne. 



Mr. Heisch read a description of improvements he had effected 

 in Nachet's Stereo-psendoscopic Binocular Microscope. (See 

 'Trans.,' p. 112.) 



Mr. Brooke 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 

 Chandlee 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, Baeef, F.C.S., stated that, in his experiments referred to in 

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

 was dialvsed in a vegetable parchment dialyser covered with filtering 

 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 might 

 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 miglit derive from silica, air, and water. He thought 

 furtlier ()bservati>ns 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. BuoWNiNG 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 



