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Ordinary Meeting, February 2()th, 1872. 



E. W. BiNNEY, F.RS, F.G.S., President, in the Chaii-. 



The President said that at the meeting of the Society 

 on the 9th of January last he alluded to the probability of 

 the genus Zygopteris being found in the limestone nodules 

 of the Foot Mine near Oldham. He had lately had an 

 opportunity of inspecting the collection of Mr. James 

 Whitaker of Watershedding, and he there recognised a 

 specimen of the Zygopteris Lacattii of M. Regnalt. There 

 was a difference between the Autun and Oldham specimens ; 

 for whilst the vascular bundles in the petiole of the former 

 were shaped like a double anchor, in the latter they came 

 nearly together and formed a circle; but he thought this 

 difference scarcely sufficient to form another species. 



Dr. J. P. Joule, F.R.S., described some experiments he 

 had been making on the polarization by frictional electricity 

 of platina plates, either immersed in water or rolled together 

 with wet silk intervening. The charge was only diminished 

 one half after an interval of an hour and a quarter. It was 

 ascertained both in quality and quantity by transmitting it 

 through a delicate galvanometer. He suggested that a con- 

 denser on this principle might be useful for the observation 

 of atmospheric electricity. 

 Peoceedings— Lit. & Phil. Soc— Yol. XI.— 'No. 10.— Session 1871-2. 



