904 TjnAxsAcrioys of the American Isstitute. 



and waslied ; afterward the filtrate is evaporated to dryness in a 

 water bath ; the residiie is exhausted with absolute alcohol, and the 

 cvanine precipitated from its solution therein b}' means of ether. 

 Cj^anine does not crystallize, is soluble in water and alcohol, and 

 insoluble in ether; acids turn it red, and alkalies green ; it is a very 

 sensitive re-agent for both. lieduciug agents decolorize cyanine ; 

 oxygen restores the color. The red coloring matter of flowers is 

 extracted in a similar manner, and, once isolated, exhibits characters 

 identical with cyanine. 



Reseaeciies ox Resins. 

 M. Sacc, in a paper published in the Annales de Chcmie et de 

 Physique, gives the result of experiments with resins, embracing 

 copal, amber, dammar, colophony or common resin, lac or shellac, 

 elemi, sandarac, mastic and carnauba wax. All these resins fused 

 quietly when heated, excepting amber, shellec, elemi, sandarac and 

 mastic, which swell up and increase in bulk. Only the carnauba 

 wax melts in boiling water; resin becomes pasty therein ; while dam- 

 mar, shellac, elemi and mastic agglutinate, copal, amber and sandarac 

 do not change. iVlcohol of eighty-six per cent strength dissolves 

 neither amber nor dammai", but agglutinates copal partly dissolves 

 elemi and carnauba wax, and coui])letely dissolves resin, shellac, san- 

 darac and mastic. Ether dissolves danimar, resin, elemi, sandarac 

 and mastic; partly dissolves carnauba wax, makes copal swell, but 

 does not dissolve amber and shellac. Acetic acid causes copal to 

 swell, acts slightly on carnauba wax, but has no effect on the other 

 resins. A hot solution of caustic soda (sp. gr. 1.074) dissolves shel- 

 lac readily, resin with difficulty, but has no action on the rest. In 

 bisulphide of carbon, amber and shellac are insoluble, dammar and 

 resin are soluble, copal simply swells, while elemi, sandarac, mastic 

 and carnauba wax are dissolved with difficulty. Oil of turpentine 

 dissolves, readily, mastic, dammar, resin, elemi, sandarac, carnauba 

 wax ; it causes copal to swell up, but has no action on amber or shel- 

 lac. Sulphuric acid of 1.83 specific gravity has no effect on carnauba 

 wax ; all other resins it dissolves and colors brown, excepting dam- 

 mar, which becomes a bright red. Nitric acid of 1.320 specific 

 gravity does not dissolve the resins, but colors carnauba wax straw 

 yellow, elemia dirty yellow, and mastic-and sandarac bright brown. 

 Ammonia does dissolve some of these resins, but causcs.copal, sandarac 

 and mastic first to swell and finally to dissolve; resin it dissolves 

 Tcry re;idily. 



