850 ADDITIONS TO THE REVISED EDITION OF 1880. 



a small quantity of nitrate of bismuth ; then freely adding a con- 

 centrated solution of carbonate of soda, or some potash lye ; then 

 heating to the boiling-point. If sugar be present, the bismuth 

 turns gray, then black. This test may be used in addition to others, 

 but is less delicate than the copper test. 



