24 METHODS OF ANALYSIS. 



the crucible from time to time in order to bring any particles adhering to the 

 sides into contact with the oxidizing material. Allow to remain over the lamp 

 for ten minutes after fusion is complete. Cool somewhat. Place warm crucible 

 and contents in a GOO cc beaker and carefully add about 100 cc of water. After 

 violent action has ceased, wash material out of crucible, make slightly acid 

 with hydrochloric acid (adding small portions at a time), transfer to a 500 cc 

 flask, cool, and make to volume. Filter, and take a 200 cc aliquot for deter- 

 mination of sulphates by precipitating with barium chlorid in the usual manner. 



9. Chlorin in Plants. Provisional. 



Impregnate 5 grams of substance in a platinum dish with 20 cc of a 5 per 

 cent solution of sodium carbonate, evaporate to dryness, and ignite as 

 thoroughly as possible. Extract the residue with hot water, filter, and wash. 

 Return to the platinum dish, ignite to an ash, dissolve in nitric acid, and 

 determine chlorin by the Volhard method (p. 23). 





