ni] PLANT CONSTITUENTS 33 



Cool somewhat, place the warm crucible and contents in a 600 cc. beaker and care- 

 fully add about 100 cc. of water. After the initial violent action has ceased, wash 

 the material out of the 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 determine sulphates in 200 cc. of the filtrate as directed under II, 20. 



18 CHLORIN IN PLANTS.— TENTATIVE. 



Moisten 5 grams of the substance in a platinum dish with 20 cc. of a 5% solution of 

 sodium carbonate, evaporate to dryness, and ignite as thoroughly as possible at a 

 temperature not exceeding dull redness. Extract with hot water, filter and wash. 

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

 add this solution to the water extract and determine chlorin as directed under 15. 



BIBLIOGRAPHY. 



' Sutton. Volumetric Analysis. 10th ed., 1911, p. 145. 



