Clear glas reagent bottle labelled 'CUPRIC SULPHATE', 1930.
© Science Museum / Science & Society Picture Library
Reagent bottle with an embosed, fired label and a ground glas stopper. A reagent is a substance or mixture used in chemical analysis. Many laboratory chemicals are stored in this type of bottle. Copper (Cupric) Sulphate (CuSO4) forms characteristic blue crystals which are readily soluble in water.