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Feb. 1 1 . — A discussion on Mr. Wonfor's paper on 

 " Flint." After which, a number of .objects, 

 illustrative of the various Avays in which silex 

 presents itself in nature, was exhibited, under 

 microscopes, by the following gentlemen : — Mr. 

 R. Smith exhibited thin sections of flints, con- 

 taining xanthidia, corals, sponge spicules and 

 dendritic oxides (commonly called moss agates), 

 and chei't, containing Pixidiilaria and other 

 organisms. — Mr. J. Dennant showed a mass of 

 silex found among the ashes of a wheat-stack 

 destroyed by fire, and silicious cuticles of wheat, 

 Indian corn, and equisetum.— Mr. R. Glaisyer 

 exhibited polycistina, from Barbadoes deposit; 

 stellate hairs of Dcutzia scahra and D. gi-acilis, 

 on young leaves, in which tlie hairs were packed 

 close together ; disintegrated glass, showing 

 markings similar to those on some diatoms ; and 

 sections of silicified coniferons wood. — Mr. 

 Hennah showed sections of flint containing a 

 sponge siphonia pyriformis and seed vessels ; 

 sections of quartz, through the optic axis, by 

 which the coloured rings were shown ; and 

 artificial diatoms, obtained from a gaseous con- 

 dition of silex by the process described by 

 Max Schultze, in which markings similar to 

 those on real diatoms were seen. These objects 

 werp exhibited under one of R. and J, Beck's 

 new large miscroscopes, with concentric rotating 

 stage, and iris diaphragm, which was kindly 

 lent by Mr. J. Beck for the occasion. There 

 was an especial interest attached to the iris 

 diaphragm, as it was the invention of Mr. 

 J. Brown, a member of the Society. — Mr. T. 

 Cooper exhibited recent and fossil sponge spi- 



