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2. On the Extraction of Mannite from the Dandelion. By 



Messrs Smith ; with an Analysis of the Mannite, by 

 Dr Stenhouse. Communicated by Dr George Wilson. 



Messrs Smith stated that thoy had extracted from the dandelion, 

 a largo amount of a crystalline sweet substance, having all the physi- 

 cal characters of mannite. It was analysed by Dr Stenhouse, and 

 found to contain carbon, hydrogen, and oxygen, in the proportions 

 which characterise the accepted formula for mannite ; viz., Cg Hj Og, 

 so that it certainly was the substance it was supposed to be. 



Messrs Widnmann and Frickhinger, it was stated, had anticipated 

 Messrs Smith in the separation of mannite from the dandelion juice, 

 and were led to believe that the mannite did not pre-exist ready 

 formed in the dandelion ; but was formed in the juice as the result 

 of a peculiar fermentation which it underwent. This result was con- 

 firmed by the Messrs Smith, who experimented with large parcels 

 of the plant, and found that even from quantities of the fresh root, so 

 large as 40 lb., no mannite could be extracted, if the expressed juice 

 were prevented from fermenting ; whilst, if fermentation were per- 

 mitted, the same weight of roots yielded a large quantity of mannite, 

 which appears to be derived from the sugar, inulin, &c., of the dan- 

 delion, which were converted into mannite, gum, and lactic acid. 



The Messrs Smith stated, in conclusion, that they had not been 

 able to confirm the statement of Polex, that the dandelion contains 

 a bitter crystallizable substance, such as he had described under the 

 name of Taraxacine. 



3. On some new Voltaic arrangements .with Chlorous and 

 Chromic Acids, with an account of a Battery, yielding elec- 

 tricity of great intensity, in which the negative, as well as 

 the positive element is Zinc. By Dr Thomas Wright. 

 Communicated by Dr G. Wilson. 



The author, after referring to the principle on which the intense 

 batteries of Daniel and Grove are constructed, and to the disadvan- 

 tages connected with the use of the porous cells in those arrange- 

 ments, stated that he had some time ago instituted a series of expe- 

 riments, with a view to the construction of a voltaic circle of high 

 electro-motive force, capable of being excited by a single solution, 

 similarly to the battery of Mr Smec. Having employed a great 



