224 



Proceedings of' Philosophical Societies, [March^ 



a female narwal , so that the fact of the tusk being peculiar to 

 the nia'e is made out beyoDd doubt. 



A paper by Dr. Wollaston vvas'also read, showing A Method of 

 T>r jji uisf very fine Wire. Muschenbroek mentioMs tliat an artist 

 of Nurember!^ drew gold wire so fine that 500 inches of it only 

 Wi-ightd one grain ; but he says nothing about the method. It 

 may be done thus : take a wire of fine silver, of a moderate 

 diameter, and drill a hole through its centre one-tenth of the 

 diameter of the whole. Fill this hole exactly with a wire of fine 

 gold. Draw out tlie silver wire, say to the fineness of -gi^-th of 

 an iiich. It is obvious that the gold wire will now be only -^-^ 

 of an inch. Put the wire into v.'arm nitric acid. The silver 

 will be dissolved, and the gold wire will remain. It being diffi- 

 cult to drill a hole in fine silver, on account of its toughness, 

 Dr. Wo*]aston tried platinum, and found it to answer. He 

 made a mold for a silver wire, fixed in its centre a fine platinum 

 ■wire, and then filled the mold with melted silver. The wire 

 was now dr.:wn out, and the silver dissolved by aqua fortis. By 

 this means he easily obtained wires of the diameters of TfV-o Tr 

 ___!__th of an inch, which is fine enough for every useful pui pose. 

 To make use of such wires the best way is to take the requisite 

 length before the silver is dissolved off, to give it the shape of an 

 U, make a hook at each extremity, suspend it by a gold wire, dip 

 it into the aqua fortis, and leave a portion of the silver at the ends, 

 which will make it much more manageable. Ihere seems to be 

 no limit to this method, except the ductility of the metals. Dr. 

 Woliaston obtained platinum wire as fine as -3-0-^^-^ th of an inch) 

 but it was impossible to obtain it thus fine of any length, 



LINN^AN SOCIETY. 



On the 2d of February a description of a plant found in India 

 by Col. Hardwicke was read, which he conceived to constitute a 

 new genus. It was found in the Mysore, and transported by the 

 Colonel to his garden, where it grew luxuriantly. It belongs to 

 the natural order of Malvactce, Its greatest length was about 

 12 feet, and its stem was about 3 inches diameter. Hence it 

 was too weak to resist violent winds when removed from the 

 forest. It belongs to the cl^ss 2J^A ov^.ev Monodtlphici Poly aii^ 

 dria. Its essential characters are, a double calyx, the outer of 

 three leaves, the inner of five. The corolla has five petals. The 

 seed vessel is divided into ten cells, containing each about ten 

 seeds in two rovv/s. Col. Hardwicke, if it should turn out to be 

 a new genus, proposes to name it after Lord Valentia, Amies- 

 ley ana, 



A description of seven new species of shells by Mr. Brooks, 

 described from his own collection, was also read. The first a 

 chama, which was figured by Gualtierij but not hitherto conss- 



4 



