Urea: Extracted from Urine with Alcohol, Precipitated as the Nitrate, Freed with Barium Carbonate

The second way Thorpe's Dictionary (1913) gives to get urea from urine: evaporate the urine to a syrup, extract the urea with alcohol, and throw it down as the sparingly soluble urea nitrate with concentrated nitric acid. Boiling the nitrate with barium carbonate and alcohol frees the urea, which crystallises from the filtered liquid. Concentrated nitric acid burns: goggles, gloves, fume hood. The picture: our diagram.