432 Dr. Stenhouse on Theine and its Preparation. 



hot water. They are readily soluble also in alcohol and aether, 

 Their great solubility renders it a little difficult to purify 

 them. The best way of doing so is by repeatedly crystallizing 

 them out of water, and by pressing them between the folds of 

 blotting-paper. When purified they are neutral, or at least 

 redden litmus paper very feebly. The smallest portion of 

 an alkali when added to their solution renders it alkaline. 

 When heated they readily sublime, and are deposited in fine 

 shining crystals on any cold object. They lake fire easily and 

 burn with a bright flame. They do not give off ammonia 

 when heated with potash. 



They occasion no precipitate or change of colour in solu- 

 tions of nitrate of silver, acetate of lead, or sulphate of iron. 



I hope soon to subjoin the results of their analysis, with a 

 more minute account of their properties. 



5th. Two lbs. of coarse black bohea tea, such as usually 

 sells for three shillings a pound, gave 99*5 grs. theine = 

 0*70 per cent. 



Analysis of the sublimed Theine. — 0*285 substance gave 

 0'5 125 carbonic acid, and 0*132 water = 



Calculated Number. 

 Carbon ... 49*72 49*79 



Hydrogen 5*14 5*08 



Analysis of Theine from Paraguay Tea. — 0*2905 dried at 

 212° gave 0*525 carbonic acid, and 0*1345 water = 



Calculated Number. 

 Carbon... 49*96 49*79 



Hydrogen 5*145 508 



The want of material unfortunately prevented me from de- 

 termining the nitrogen also. 



Hydrochlorate of theine forms a double salt with chloride 

 of platinum. It may be easily obtained in small but very 

 distinct orange-coloured crystals by adding chloride of pla- 

 tinum to a hot solution of theine in hydrochloric acid. In a 

 few minutes as the liquor cools the crystals begin to form, 

 and gradually subside as a mass to the bottom of the vessel. 

 When dried at 212° and burnt, 



Calculated 

 Per cent. Number. 



I. 0*461 grs. salt gave 0*112 of platinum = 24*29 . . . 24*48 



II. 0*529 ... 0*130 ... = 24*57 

 111.0*5828 ... 0*143 ... = 24*53 

 IV. 0*458 ... 0*112 ... =24*45 



These numbers lead to the rational formula C 16 H 10 N 4 O 4 

 H CI + Pt Cl% which gives 24*48 per cent, platinum, and 

 double the ordinary atomic weight of theine. 



