The liquid then contains nothing but nitroprusside and nitrate of potash or soda.
"A System of Instruction in the Practical Use of the Blowpipe" by Anonymous
The nitroprusside, however, gives a beautiful crimson-purple coloration.
"The Chemistry of Hat Manufacturing" by Watson Smith
Add a few drops of sodium nitroprusside solution, make alkaline with ammonia, then saturate with ammonium sulphate crystals.
"The Elements of Bacteriological Technique" by John William Henry Eyre