174 UEEA. 



a water-bath ; exhaust the residue with hot alcohol ; 

 evaporate the solution to dryness; take up with 

 absolute alcohol; evaporate the solution to .dryness, 

 when crystals of urea will be obtained. 



2. Evaporate a solution of cyanate of ammonium to 

 dryness on a water-bath; crystals of urea will be 

 obtained. 



3. Urea is very soluble in water, and alcohol, nearly 

 insoluble in ether ; on heating, it melts and then de- 

 composes. Examine the crystals under the micro- 

 scope. 



4. Take a small quantity of urea, dissolve in water, 

 add a saturated solution of sodium carbonate, place 

 the whole in a flask, and distil through a Liebig's 

 condenser previously well washed with distilled water ; 

 collect the distillate ; on adding some Nessler test- 

 solution a dark-brown colour will be immediately 

 formed, proving the decomposition of the urea into 

 ammonia and carbonic acid. 



5. Add to an aqueous solution of urea a solution of 

 nitrate of mercury; a white precipitate of mercuric 

 oxyde and nitrate of urea falls. 



6. Half fill a test-tube with an aqueous solution of 

 urea, fill up the tube with a solution of hypochlorite, 

 close the test-tube with the thumb, invert the whole 

 once or twice to mix the contents thoroughly, and, 

 finally, invert the tube under the surface of a saturated 

 aqueous solution of salt. Allow to stand ; bubbles of 

 gas will soon be disengaged, and collect in the upper 

 part of the test-tube. This gas is nitrogen formed 

 from the decomposition of the urea. 



