Intelligence and Miscellaneous Articles. 555 



The double chlorogenate contains— 



Chlorogenic acid 63*5 



Potash 7-5 



Caffeine 29- 



Too 7 " 



Caffeine therefore acts the part of a base in the composition of the 

 natural double salt. This new compound exists in its original state 

 in the perisperm of the coffee berry, from which it is readily extracted. 



Among the curious properties of chlorogenic acid, the remarkable 

 power which it possesses of developing a very intense green colour, 

 adds interest to the discovery of the crystallizable compound, which 

 its rapid and variable transformations have hitherto prevented from 

 being observed. — Journ. de Pharm., Octobre 1846. 



ANALYSIS OF TALC AND STEATITE. 



M. Delesse observes that talc and steatite are common in nature, 

 but that mineralogists do not agree as to their composition. Ac- 

 cording to his analysis, the talc of Rhode Island in the United States 

 consists of — 



Silica 61*75 



Magnesia 31*68 



Protoxide of iron .... 1*70 



Water 483 



99-96 

 The water exists so combined that it is impossible to expel it by 

 the heat of a spirit-lamp, as found by M. Marignac in operating 

 on the talc of Chamouny ; to expel the water perfectly the mineral 

 must be kept at a white heat in a calcining furnace. 



The steatite examined by M. Delesse was of a milk-white colour, 

 and came from Nyntsch in Hungary ; it is the Speckstein of German 

 mineralogists ; the water is not expelled from it by the heat of a 

 spirit-lamp. It was found to consist of — 



Silica 64-85 



Magnesia 28*53 



Protoxide of iron .... 1'40 

 Water 5-22 



100* 

 Journ. de Pharm. et de Ch., Septembre 1846. 



CAUSE OF THE EFFLORESCENCE OF LAUMONITE. 



MM. Malaguti and Durocher state, that the efflorescence of lau- 

 monite is owing to the loss of a small quantity of water. This 

 mineral did not suffer the least alteration when kept for several 

 months in a moist atmosphere. Crystals of laumonite altered, re- 

 covered their original transparency and appearance by being im- 

 mersed in water ; and these same crystals, after drying and exposure 



2 P2 



